CN112114480A - Laser projection device - Google Patents

Abstract

The invention provides laser projection equipment, which comprises a whole machine shell, a light source, an optical machine and a lens, wherein the light source is arranged on the whole machine shell; the light source comprises a red laser component, a green laser component and a blue laser component, wherein the red laser component and the green laser component are arranged in parallel, and the blue laser component is vertical to the red laser component and the green laser component; and a second light combining mirror is arranged at the intersection of the blue laser, the green laser and the red laser after light combination, reflects the red laser and transmits the blue laser and the green laser, and outputs the three-color laser to a light source light outlet. The laser projection equipment has small light loss of red laser, is beneficial to maintaining the power ratio or the color ratio of three-color laser beams, and can present a projection picture with high brightness and good color.

Description

Laser Projection Equipment

technical field

The present invention relates to the technical field of laser projection display, in particular to a laser projection device.

Background technique

The laser light source has the advantages of good monochromaticity, high brightness and long life, and is an ideal light source. As the power of laser devices increases to meet the requirements of industrial applications, lasers are gradually used as light sources for illumination. For example, in recent years, lasers have been used as projection light sources in projection equipment, gradually replacing mercury lamp illumination. Compared with LED light sources, lasers also have the advantages of small etendue and high brightness.

Lasers are divided into blue lasers, red lasers and green lasers according to the type of light emission, which emit blue lasers, red lasers and green lasers respectively. Among them, due to the different light-emitting mechanisms, as shown in Figure 22, the red laser light-emitting chip has two light-emitting points, but one light-emitting chip corresponds to one collimating lens. Therefore, one collimating lens collimates the two light-emitting points. The straightening effect is worse than the collimating effect of a collimating lens on a light-emitting point, which makes the divergence angle of the red laser light from the light-emitting surface of the laser component larger than that of the other two color lasers. The three-color laser is shared. In the process of beam transmission, the optical lens experienced usually has its own light-receiving range or has a high light processing efficiency within a certain angle range. For red laser, due to the faster divergence degree , so that the beam with a large angle range is easily lost, so the light loss of the red laser is usually large, and this loss rate is difficult to estimate, and it is difficult to solve it by the method of power compensation.

It is necessary to propose a solution to solve the problem of the large light loss of the red laser in the application of the three-color laser, which leads to the imbalance of the color ratio of the system and the poor quality of the projected image.

SUMMARY OF THE INVENTION

The invention provides a laser projection device, which includes a three-color laser light source, and can present a projection screen with high brightness and good color.

The invention provides a laser projection device: a complete machine casing, a light source, an optical machine and a lens;

The light source includes a red laser component and a green laser component installed in parallel, and a blue laser component perpendicular to the red and green laser components; a first light combining mirror is arranged at the intersection of the blue laser and the green laser, and the first light combining mirror The blue laser is transmitted, the green laser is reflected, and a second light combining mirror is arranged at the intersection of the combined blue laser, green laser and red laser, and the second light combining mirror reflects the red laser and transmits the blue and green lasers, Output the three-color laser to the light outlet of the light source;

Further, the light reflectivity of the first light combining mirror and the second light combining mirror are both greater than their light transmittances;

Further, the luminous power of the green laser component is smaller than the luminous power of the red laser component and the blue laser component;

Further, the spot size of the red laser light reaching the second light combining mirror is larger than that of the blue laser and the green laser;

Further, in the light path from the second light combining mirror to the light outlet of the light source, a homogenizing element and a condensing lens group are also arranged in sequence;

Further, a diffusing sheet is also provided in the light path from the first light combining mirror to the second light combining mirror, for diffusing and transmitting the green laser and the blue laser;

Further, the homogenizing element is a diffuser with regularly arranged microstructures, or the homogenizing element is a two-dimensional diffractive element;

Further, the light beam of the three-color light source enters the light-receiving part through the diffusing wheel after exiting from the light-source light outlet;

Further, a half-wave plate is also provided in the light path from the first light combining mirror to the second light combining mirror;

The half-wave plate is set corresponding to the wavelength of the green laser, or the half-wave plate is set corresponding to the wavelength between the green laser and the blue laser.

Further, half-wave plates are respectively provided in the light paths between the light-emitting surfaces of the blue laser components and the green laser components to the first light combining mirror, and the half-wave plates are respectively arranged corresponding to the wavelength of the blue laser and the wavelength of the green laser;

Further, the polarization directions of the blue laser and the green laser are the same, and the polarization directions of the red laser and the above-mentioned two color lasers are different;

Further, the luminous power of the red laser component is 24W~56W, the luminous power of the blue laser component is 48W~115W, and the luminous power of the green laser component is 12W~28W.

The laser projection device of one or more of the above embodiments uses a three-color laser light source, the red laser is output from the light source light outlet after one reflection, the blue laser is transmitted twice, and the green laser is transmitted once and reflected once and then output from the light source. The output of the light source light outlet, the light loss of the red laser is small, which is conducive to maintaining the power ratio or color ratio of the three-color laser beam. The above-mentioned laser projection equipment can present a projection image with high brightness and good color.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

FIG. 1 is a schematic diagram of the overall structure of a laser projection device in an embodiment of the present invention;

2 is a schematic diagram of a DLP projection architecture according to an embodiment of the present invention;

3 is a schematic diagram of an ultra-short-focus projection imaging optical path in an embodiment of the present invention;

4 is a schematic diagram of an ultra-short-focus projection system in the implementation of the present invention;

5 is a structural diagram of an ultra-short-focus projection screen in an embodiment of the present invention;

Fig. 6 is the reflectivity change diagram of projection screen to projection beam among Fig. 5;

FIG. 7 is a schematic structural diagram of a light source of a laser projection device in FIG. 1 according to an embodiment of the present invention;

FIG. 8 is a schematic exploded view of the structure of FIG. 7;

FIG. 9 is a schematic diagram of the assembly of a laser assembly in an embodiment of the present invention;

10 is a schematic diagram of another laser group assembly in the embodiment of the invention;

11 is a schematic diagram of an exploded structure of a laser assembly in an embodiment of the invention;

12 is a schematic diagram of an exploded structure of another laser assembly in an embodiment of the invention;

13 is a schematic diagram of an exploded structure of another laser assembly in an embodiment of the invention;

14 is a schematic structural diagram of an MCL laser;

FIG. 15 is a schematic diagram of the packaging structure of the laser circuit in FIG. 14;

16 is a schematic diagram of the principle of the light path of a light source in an embodiment of the present invention;

17 is a schematic diagram of the optical path principle of another light source in an embodiment of the present invention;

18 is a schematic structural diagram of another angle light source in an embodiment of the present invention;

19 is a schematic diagram of a heat dissipation system of a red laser component in an embodiment of the present invention;

FIG. 20 is a schematic diagram of the assembly of the heat dissipation system of the blue or green laser component in the embodiment of the present invention;

FIG. 21 is an exploded schematic diagram of a heat dissipation system of a blue or green laser component in an embodiment of the present invention;

Figure 22 is a schematic diagram of the structure of a red laser chip;

23 is a schematic diagram of the optical path principle of a laser projection system according to an embodiment of the present invention;

24 is a schematic diagram of the optical path principle of another laser projection system according to an embodiment of the present invention;

25 is a schematic structural diagram of a diffuser sheet according to an embodiment of the present invention;

26 is a schematic diagram of the energy distribution of the laser beam after passing through the diffuser shown in FIG. 25 according to an embodiment of the present invention;

27 is a schematic diagram of a light spot in an optical path according to an embodiment of the present invention;

Figure 28 is a schematic diagram of the optical axis of a wave plate;

Figure 29 is a schematic diagram of the principle of a 90-degree change in linearly polarized light;

30 is a schematic diagram of the polarization directions of P light and S light;

Figure 31 is a schematic diagram of wave plate rotation setting;

32 is a schematic diagram of an optical path principle in an embodiment of the present invention;

33 is a schematic diagram of another optical path principle in an embodiment of the present invention;

34 is a schematic diagram of another optical path principle in an embodiment of the present invention;

Description of reference numbers:

10-laser projection equipment, 101-housing;

100-light source, 102-light source housing, 1021-window, 1022-air pressure balance device, 1023-adjustment structure installation position, 103-first light outlet, 104-fixing bracket, 1041-light transmission window, 1042-third seal Pieces; 105-sealing glass, 1051-first sealing piece, 1052-second sealing piece, 106-first light combining mirror, 107-second light combining mirror, 108-diffusion sheet, 109-homogenization element, 110- Blue laser assembly, 111-converging lens group, 120-green laser assembly, 130-red laser assembly, 121, 131, 141, 151, 140-half-wave plate;

1101-collimating lens group, 1102-metal substrate, 1103-laser pin, 1104a, 1104b-PCB board;

200-optical machine, 201-second light entrance, 202-third light exit, 210-illumination light path, 220-DMD digital micromirror array, 230-galvanometer, 250-light receiving part, 260-diffusion wheel;

300-lens, 310-refractive lens group, 320-reflector group;

400-projection screen, 401-substrate layer, 402-diffusion layer, 403-uniform medium layer, 404-Fresnel lens layer, 405-reflection layer;

500 - circuit board;

601- cooling fin, 602- heat pipe, 603- heat conduction block, 604- first fan, 605- second fan, 606- third fan, 607- fourth fan, 610- cold head, cold row-611, liquid replenishment Device - 612, 613 - Thermal Block.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

First, according to the laser projection device shown in FIG. 1 , the structure and working process of the laser projection device of this embodiment will be described.

FIG. 1 shows a schematic structural diagram of a laser projection device. The laser projection device 10 includes a complete casing 101, and according to the optical functional parts, also includes a light source 100, an optical engine 200, and a lens 300. These optical parts have corresponding casings Packing is carried out, and certain sealing or airtight requirements are met. For example, the light source 100 is airtightly sealed, which can better prevent the problem of light decay of the light source 100 . The light source 100 , the optical machine 200 , and the lens 300 are installed in the whole casing 101 . Wherein, the optical machine 200 and the lens 300 are connected and arranged along the first direction of the whole machine casing 102. As shown in FIG. 1, the first direction can be the width direction of the whole machine, or according to the usage mode, the first direction can be viewed by the user. relative direction. The light source 100 is arranged in the space enclosed by the optical machine 200 , the lens 300 and a part of the whole casing 101 . The light source 100 is a pure three-color laser light source, emitting red laser, blue laser and green laser.

Referring to FIG. 1 and FIG. 8 , the light source 100 has a first light exit 103, and the optomechanical 200 has a second light entrance 201 and a third light exit 202. According to the design of the light path of the internal lighting of the optomechanical, the second light entrance 201 and the third The light outlet 202 is located on different sides of the optical machine in a vertical relationship, and the vertical here is the vertical in the spatial position relationship. . The first optical outlet 102 of the light source 100 is connected to the second optical inlet 201 of the optical machine 200. The light beam of the light source 100 enters the optical machine 200, passes through the illumination light path inside the optical machine 200 and reaches the light modulation device, and the light modulation device converts the illumination beam. Output to lens 300.

Specifically, the optical machine 200 contains a light modulation device, which is the core component of the system. Light modulation device (also called light valve) can be divided into liquid crystal light valve LCD, liquid crystal on silicon LCOS, and DMD digital micromirror chip. The DMD chip is used in the DLP projection architecture.

Figure 2A shows a DLP (Digital Light Processing) projection architecture, in which a DMD (Digital Micromirror Device) digital micromirror array is the core device of the entire projection architecture. The following takes a single-chip DMD application as an example for description. DMD220 is a reflective light valve device. The illumination beam output from the light source usually needs to pass through the illumination optical path 210 at the front end of the DMD220. After passing through the illumination optical path 210, the illumination beam conforms to the illumination size and incident angle required by the DMD220. The surface of the DMD220 includes thousands of tiny mirrors, each of which can be driven to deflect independently. For example, in the DMD chip provided by TI, it can be deflected by plus or minus 12 degrees or plus or minus 17 degrees. Among them, the light reflected by a positive deflection angle is called ON light, and the light reflected by a negative deflection angle is called OFF light. . The ON light is an effective light beam that the tiny reflecting mirror on the surface of the DMD light valve receives the illumination light beam and enters the lens part 300 through a positive deflection angle, and is used for projection imaging.

In this example, the optomechanical 200 applies a DLP projection architecture, and uses a DMD reflective light valve as the light modulation device.

Referring to FIG. 1 , the lens 300 is connected to the optomechanical 200 through the third light outlet 202 , and the specific connection may be locked by screws through the end faces of the respective housings, wherein part of the lens group of the lens 300 also extends into the first part of the optomechanical 200 . Sanguang exit 202.

The lens part 300 includes a plurality of lens combinations, which are usually divided into groups, and are divided into three-stage front group, middle group, and rear group, or front group and rear group. group, the rear group is the lens group close to the light-emitting side of the light modulation device. According to the combination of the above-mentioned various lens groups, the lens part 300 may also be a zoom lens, a fixed-focus adjustable focus lens, or a fixed-focus lens.

The laser projection device in this example is an ultra-short-throw projection device, so the lens part 300 is an ultra-short-throw projection lens, and its throw ratio is generally less than 0.3, such as 0.24. The ultra-short focal projection lens can be the one shown in FIG. 3 , including a refractive lens group 310 and a mirror group 320 , and the mirror group 320 can be a curved mirror. As shown in FIG. It is projected obliquely upward to the projection screen 400 for imaging, which is different from the traditional telephoto projection in which the optical axis of the projection beam is located on the vertical line of the projection screen. The ultra-short focus projection lens usually has 120%~150% relative to the projection screen. offset.

Due to the small size of the DMD chip, for example, the size of the DMD chip currently provided by TI is 0.66 inches, 0.65 inches, and 0.47 inches, and the projection screen size is usually above 70 inches, such as between 80 inches and 150 inches, so for the lens For the part 300, it is necessary to achieve hundreds of times magnification, correct aberrations, and have good resolution to present high-definition projection images. The design of ultra-short-focus projection lenses is much more difficult than long-focus projection lenses.

In the ultra-short-throw projection equipment, the center vertical line of the light-emitting surface of the DMD light valve is usually parallel to the optical axis of the lens, but not coincident, that is, the DMD is offset to the lens part 300, and the light beam emitted from the light-emitting surface of the DMD is obliquely incident at a certain angle In the lens portion 300 , through transmission and reflection of partial regions of the plurality of lenses, the final projection light beam is emitted obliquely upward from the lens portion 300 .

As a light modulation device, the DMD is driven by an electrical signal to modulate the light, so that the light beam carries image information, and is finally enlarged by the lens to form a projection image.

On the basis of the relatively fixed resolution of the DMD itself, in order to achieve a higher definition and resolution image, as shown in FIG. 3, a galvanometer 230 can also be set in the light path of the DMD exit light path to the lens, and the galvanometer 230 It is a transmissive flat sheet structure. Through one-dimensional vibration, the galvanometer angularly displaces the successively transmitted image beams, so that two adjacent images will be dislocated and superimposed and then imaged on the projection screen. Using the visual persistence effect of the human eye, the information of the two images is superimposed. As an image information, the details of the image perceived by the human eye increase, and the resolution of the image is also improved.

The galvanometer can also perform two-dimensional motion, such as moving in four positions, up, down, left, and right, so that the four images can be dislocated and superimposed together, and the above-mentioned principle of information superposition can be used to achieve the effect of improving the resolution perceived by the human eye. Whether the above two images are superimposed or four images are superimposed, the two sub-images or the four sub-images need to be decomposed by a high-resolution image in advance, and the decomposition method needs to be matched with the movement mode of the galvanometer. , in order to overlay correctly without cluttering the image.

The galvanometer is usually set between the DMD light valve and the lens. The beam transmitted between the DMD and the lens can be approximately regarded as a parallel beam. The parallel beam can still maintain good parallelism after being refracted by the flat plate, but if the divergence angle is relatively After a large beam is refracted through a flat plate, the angle of refraction changes greatly, which may cause uneven brightness or chromaticity when the two image beams passing through the galvanometer successively are superimposed.

Referring to FIG. 1 , a space enclosed by the optical machine 200 , the lens 300 and another part of the whole machine casing 101 is provided with a plurality of circuit boards 500 , and the plurality of circuit boards 500 include a power supply board, a TV board, a control board, a display board, etc., The plurality of circuit boards 500 are usually stacked in layers, or a part of the plurality of circuit boards 500 may be placed along the bottom surface of the whole casing 101 , and some are arranged along the side surface of the whole casing 101 .

In addition, in the laser projection apparatus 10, along the inner side of the whole casing 101, structures such as a speaker, a fan, and a heat sink are also provided.

In the laser projection equipment provided by the above-mentioned embodiments, the optical machine 200 and the lens 300 are arranged along the first direction of the whole casing 101 of the equipment, and the whole machine is divided into two parts, one part can accommodate the light source, and the other part can accommodate the circuit board, These two parts are the left and right parts as shown in Figure 1, respectively. Such a division can be viewed as separating the optical and electrical parts. It should be noted that the optical part is also usually provided with a drive circuit, but since the circuit parts such as the display panel, signal panel, and power supply panel are smaller in size and less complex, it can be considered that the left half of the main body is optical part, the main body of the right half is the circuit part. In this way, different main bodies are set separately, which is not only convenient for the assembly and debugging of the whole machine, but also convenient for the design requirements of the optical part and the electrical part, such as heat dissipation, wiring, and electromagnetic testing.

And, in the laser projection device provided in this example, the optical machine 200 and the lens 300 are arranged in the same direction, and part of the lens group of the lens 300 extends into the optical machine 200, which is beneficial to reduce the assembled volume of the optical machine and the lens. And according to the light output characteristics of the reflective light valve, although subject to different illumination light path structures, the light beam of the light source 100 may be turned several times and finally enter the lens 300, but the direction of the light beam emitted from the first light outlet 103 of the light source 100 and the lens Compared with the beam direction of the light incident surface of the light source 300 , it can be considered that the optical axis direction of the light beam of the light source 100 and the optical axis direction of the lens 300 have a vertical relationship in spatial position. The light source 100 , the optomechanical 200 and the lens 300 are connected and assembled to form an L shape, which provides a structural basis for the turning of the optical axis of the beam, and not only reduces the difficulty of designing the optical path of the optomechanical 200 incident lens 300 . The overall layout of the above-mentioned laser projection equipment is relatively compact, and the optical path structure is also more concise.

Therefore, in this example, the light source 100 is used to provide light source illumination for the opto-mechanical 200 . Specifically, the light source 100 provides the opto-mechanical 200 with illumination beams by sequentially and synchronously outputting three primary color illumination beams.

The light source 100 can also be non-sequential output, and there are superimposed output periods of different primary colors. For example, red and green have superimposed output periods. Increasing the proportion of yellow in the beam period is beneficial to improve the brightness of the image, or red, green, and blue at the same time. Part of the time period is lit, and the three colors are superimposed to form white, which can improve the brightness of the white point.

And, when other types of light modulation components are used, in order to cooperate with the three-piece LCD liquid crystal light valve, the three-color primary light in the light source part can simultaneously light up and output mixed white light. In this example, although the light source unit 100 outputs three primary colors of light in a sequential manner, according to the principle of three-color mixing, the human eye cannot distinguish the color of the light at a certain moment, and still perceives mixed white light. Therefore, the output of the light source unit 100 is generally also referred to as mixed white light.

7 is a schematic diagram of a partial structure of the light source 100 in FIG. 1 , and FIG. 8 is a schematic diagram of an exploded structure of FIG. 7 . An example of a three-color laser light source will be described below with reference to the accompanying drawings.

As shown in FIG. 7 , the light source of the light source 100 includes a light source housing 102 , and blue laser components 110 , green laser components 120 and red laser components 130 installed on different sides of the light source housing 102 , respectively emitting blue laser light and green laser light. and red laser. The green laser assembly 120 and the red laser assembly 130 are installed side by side on the same side, and both are perpendicular to the blue laser assembly 110 in spatial position, that is, the light source housing where the green laser assembly 120 and the red laser assembly 130 are located The side surface is perpendicular to the side surface of the light source housing where the blue laser assembly 110 is located, and the two side surfaces are both perpendicular to the bottom surface of the light source housing 102 or the bottom surface of the entire machine housing 101 .

16 is a schematic diagram of an optical path of the light source 100. As shown in FIG. 16, the green laser assembly 120 and the red laser assembly 130 are arranged side by side, and the light exit surface of the blue laser assembly 110 faces the light exit port of the light source. The light beam emitted by the blue laser assembly 110 is transmitted and output to the light outlet of the light source 100 without the need for turning the light path.

The light beam from the red laser component exits from the light outlet after one reflection, and the light beam from the green laser component exits from the light exit after one reflection and one transmission. It can be seen that in the above schematic diagram of the optical path, the red laser has the shortest optical path and the least number of reflections.

Referring to FIGS. 7 and 5B , the laser components of any color above output a rectangular light spot, and the laser components of any color are vertically installed on the side surface of the light source housing 102 along the longitudinal direction of the respective rectangular light spots. In this way, the laser light spot output by the three-color laser assembly will not form a "cross"-shaped light spot when combining light, which is beneficial to the reduction of the combined light spot size and the higher homogenization degree.

As shown in FIG. 8 , the light source housing 102 includes a plurality of side surfaces, a bottom surface and a top cover, and a plurality of optical lenses in the light source 100 are arranged on the bottom surface of the light source housing 102 . In order to increase the heat dissipation area, the top cover of the light source housing 102 is fin-shaped. A plurality of windows 1021 are opened on the side of the light source housing 102 to install the above-mentioned plurality of laser components. The light beams emitted by the above-mentioned laser components of any color are incident on the internal cavity of the light source 100 from the corresponding installation windows, and pass through the plurality of laser components. Optical lenses form a light transmission path.

In this example, some control circuit boards (not shown) are also installed on the top cover of the light source housing 102, and, as shown in FIG. There is an adjustment structure installation position 1023 for an optical lens.

And, as shown in FIG. 18 , an air pressure balancing device 1022 is also provided on the bottom surface or the top cover of the light source housing 102 . The air pressure balancing device 1022 can be a filter valve, which can be used to connect the inner cavity of the light source with the outside to realize the exchange of air flow. When the temperature of the inner cavity of the light source increases, the inner air flow flows out, and when the temperature recovers and cools, the outer air flow can also be used. Entering the inner cavity of the light source, since the filter valve can be set as an airtight and waterproof filter membrane, it can filter the particles, dust, etc. within a certain diameter range from the outside, block it, and maintain the cleanliness of the inner cavity of the light source. Alternatively, the air pressure balancing device is a retractable air bag, and the air bag can be made of elastic rubber, which is used to increase the volume of the light source cavity when the air pressure increases, so as to relieve the air pressure of the light source cavity. The above-mentioned air pressure balancing devices can be used as pressure relief devices. When the temperature of the inner cavity of the light source rises too high, the pressure is released to the outside through communication or by forming a gas containing structure to increase the volume of the sealed space in the inner cavity of the light source. The air pressure of the cavity is balanced, and the reliability of the optical devices in the cavity of the light source is improved.

Since the assembly structure of the three-color laser assembly and the light source housing is basically the same, in order to simplify the connection between the laser assembly and the light source housing, the following will take the assembly structure of any one of the color laser assemblies as an example for description.

The above three-color laser components are all MCL-type laser components, that is, a plurality of light-emitting chips are packaged on a substrate to form a surface light source output. As shown in FIG. 14 and FIG. 15, an MCL type laser includes a metal substrate 1102, and a plurality of light-emitting chips (not shown in the figure) are packaged on the metal substrate 1102. The plurality of light-emitting chips can be connected in series or arranged in a row Or the columns are driven in parallel. Multiple light-emitting chips can be arranged in a 4X6 array, or other array arrangements, such as a 3X5 array, or a 2X7 array, or a 2X6 array, or a 4X5 array. The overall luminous power of lasers with different array numbers is different. Pins 1103 protrude from both sides of the metal substrate 1102. By connecting these pins with electrical signals, the light-emitting chip can be driven to emit light. A collimating lens group 1101 is also disposed on the light-emitting surface of the MCL laser, and the collimating lens group 1101 is usually fixed by gluing. The collimating lens group 1101 includes a plurality of collimating lenses, which generally correspond to the light-emitting positions of the light-emitting chips one-to-one, and perform corresponding collimation on the laser beam.

As shown in FIG. 15 , the MCL laser assembly also includes PCB boards 1104a and 1104b arranged on the outer peripheral side of the MCL laser. The PCB boards 1104a and 1104b are parallel to or in the same plane as the light-emitting surface of the laser, so as to drive the laser pins 1103 , as The laser provides the drive signal. As shown in the figure, the circuit board is a flat plate structure, and the two sides of the laser have pins 1103. The pins 1103 are respectively welded or plugged on the side circuit boards 1104a and 1104b that are almost parallel to the plane where the laser is located. Among them, 1104a and 1104b It can be integrally formed and surround the outer side of the laser component substrate 1102, or 1104a and 1104b can also be two independent circuit boards, which enclose the laser component, so that the packaged laser component is basically a flat structure, which is convenient for It is easy to install, saves space, and is also conducive to the miniaturization of light source equipment.

FIG. 9 and FIG. 11 are respectively a schematic diagram of the assembly structure of any color laser assembly and a fixing bracket, and a schematic diagram of an exploded structure.

As shown in FIG. 8 , the laser components of any color are installed at the window 1021 of the corresponding light source housing through the fixing bracket 104 , and the fixing bracket 104 and the light source housing 102 are locked by screws, thereby fixing the laser component at the position of the window 1021 . Any color laser assembly includes MCL type laser assembly and fixing bracket.

The laser components of any color are locked on the fixing bracket by screws. Specifically, the metal substrate of the MCL laser is provided with an assembly hole, which can be locked with the fixing bracket.

As shown in FIG. 11 , the fixing bracket 104 is a sheet metal part with a light-transmitting window 10211 . The front side of the light-transmitting window 1401 of the fixing bracket 104 is installed close to the window 1021 of the light source housing 102 , and the laser components of any color are installed on the fixing bracket 104 . On the installation position on the back of the light-transmitting window 10211 of the bracket. In addition, in order to improve the sealing performance of the installation structure, a third sealing member 1042 is provided at the rear installation position of the light-transmitting window 10211 of the fixing bracket. the front of the laser, and then fix the MCL laser assembly at the installation position. The third sealing member 1042 can also play a buffer role to prevent the collimating lens group on the surface of the MCL laser from being damaged due to hard contact with the sheet metal part.

The MCL laser assembly is composed of the MCL laser and the corresponding PCB board 1104 . The MCL laser assembly is fixed to the fixing bracket 104 and becomes an assembly unit, and is installed together at the position of the window 1021 corresponding to the light source housing 102 . Specifically, there are studs around the window 1021, and the studs around the window are driven through the studs of the fixing bracket by screws.

Since the light source 100 is provided with a plurality of optical lenses, which are precision components, and the energy density during the beam transmission process is very high, if the internal environment is not clean, dust particles will accumulate on the surface of the precision lenses, resulting in a decrease in the light processing efficiency. As a result, the light decay of the optical path is caused, and the brightness of the entire laser projection equipment will also decrease accordingly. In this example, dustproofing the inside of the light source can alleviate the above-mentioned problem of light decay. Specifically, as shown in FIG. 12 , a sealing glass 105 is also provided at the window 1021 , and the sealing glass 105 is installed between the inner cavity of the light source and the window 1021 The laser components are isolated, so that external dust, etc. will not enter the cavity of the light source from the opening of the window. The sealing glass 105 can be arranged on the surface of the inner cavity of the light source, such as by bonding, or it can be arranged on the side of the light source housing close to the laser assembly, for example, by setting an installation position on the outer surface of the light source housing, and sequentially connecting the laser assembly. , the sealing glass is installed on the outside of the light source housing window.

As shown in the exploded structure shown in FIG. 12 , in order to facilitate the installation of the sealing glass, in this example, the sealing glass 105 is installed on the side of the window 1021 close to the laser assembly. There is also a first accommodating groove on the front of the fixing bracket 104 for accommodating the first sealing member 1051 , and a second accommodating groove at the window 1021 of the light source housing for accommodating the second sealing member 1052 . The sealing glass 105 is located between the first sealing member 1051 and the second sealing member 1052. Specifically, the second sealing member 1052 is placed in the second accommodating groove at the window 1021. 105 is matched with the fixing slot, the sealing glass 105 is placed in the fixing slot, and the first sealing member 1051 is installed into the first accommodating slot of the light-transmitting window 10211 of the fixing bracket through interference fit, and then the fixing bracket is installed. Any color laser assembly composed of the MCL laser assembly is installed at the window 1021 of the light source housing, and the first sealing member 1051 is in pressing contact with the sealing glass 105. With the completion of the fixing of the laser assembly, the sealing glass 105 is also clamped. The first sealing member 1051 and the second sealing member 1052 are fixed.

And, in the above examples, the MCL laser assembly of any color is fixed to the fixing bracket by the shoulder screw, and a shock absorber is also arranged between the shoulder screw and the fixing bracket, which can reduce the laser at higher frequencies. Noise transmission generated during driving.

The assembly structure of the laser assembly and the light source housing has been described above. The above-mentioned laser assembly is mounted on the light source housing, emits a laser beam under the control of a driving signal, forms an optical path output inside, and cooperates with an optical machine and a lens to perform projection imaging.

In laser projection equipment, the light source is the main heat source, and the high-density energy beam of the laser irradiates the surface of the optical lens to generate heat. The DMD chip has an area of tenths of an inch, but needs to withstand the beam energy required for the entire projected image, and its heat generation is also very high. On the one hand, the laser has a set working temperature to form a stable light output, taking into account the service life and performance. At the same time, the device contains multiple precision optical lenses, especially the ultra-short focal lens contains multiple lenses. If the temperature is too high, the heat will accumulate, which will cause the "warm drift" of the lens in the lens, and the image quality will be seriously degraded. In addition, components such as circuit board devices are driven by electrical signals and generate a certain amount of heat, and each electronic device also has a set operating temperature. Therefore, good heat dissipation and temperature control are very important guarantees for the normal operation of laser projection equipment.

Specifically, as shown in FIG. 20 and FIG. 21 , the heat transfer block 603 is in contact with the heat sink of the green or blue laser assembly to conduct heat, the outer surface of the heat pipe 602 is in contact with the heat transfer block to realize heat transfer, and one end of the heat pipe 602 in contact with the heat transfer block 603 It is the hot end, and the other end is in contact with the cooling fins, which is the cold end. The heat pipe is a closed system with liquid inside, and the heat conduction is realized by the change of liquid gas and liquid. The heat dissipation fins in contact with the cold end of the heat pipe are usually cooled by air cooling, so that the cold end of the heat pipe is also cooled, and the gas is liquefied and returned to the hot end of the heat pipe.

And, as shown in FIG. 19 , the red laser assembly is connected to the cold head 610 to dissipate heat by means of liquid cooling. In the liquid cooling circulation system, the cold head takes away the heat of the heat source components and returns to the cold row, the cold row is cooled, and the cooled coolant, for example, commonly used water, flows back to the cold head again, and circulates the heat source in turn. Conduct heat transfer. In the liquid cooling circulation system, a pump is also included to drive the cooling liquid in the liquid cooling circulation system to keep flowing. In this example, the pump and the cold head are integrated to reduce the volume of the components. The cold head mentioned below It can refer to the integrated structure of the cold head and the pump. And, in the liquid cooling circulation system of the laser projection device of this example, a liquid replenisher is also included, which is used for replenishing the liquid cooling circulation system, so that the liquid pressure in the entire liquid cooling circulation system is greater than the external pressure of the system, so that the external gas will not Due to the volatilization of the coolant or the poor sealing of the pipe joints, it enters the circulation system, causing internal noise in the circulation system, and even cavitation and damage to the device.

Compared with the air-cooled heat dissipation system, the liquid-cooled circulation system is more flexible in that the volume of the cold head and the cold row is smaller than that of the traditional heat dissipation fin, and the choice of its own shape and structure position is more diverse. Since the cold head and the cold exhaust are connected through pipes, it is always a circulation system, so the cold exhaust can be set close to the cold head, or there can be other relative positions, which is determined by the space of the laser projection equipment.

A plurality of circuit boards 500 and a second fan are also arranged in the space enclosed by the optical machine, the lens and another part of the whole casing.

In the laser projection apparatus, the light source 100 is a laser light source, and the included laser components of different colors have different operating temperature requirements. Among them, the working temperature of the red laser component is less than 50 °C, and the working temperature of the blue laser component and the green laser component is less than 65 °C. The operating temperature of the DMD chip in the optical machine is usually controlled at about 70°C, and the temperature of the lens part is usually controlled below 85°C. For the circuit board part, the temperature control of different electronic devices is different, usually between 80°C and 120°C. It can be seen that due to the different temperature tolerance values of optical components and circuit parts in the device, the operating temperature tolerance value of the optical part is generally lower than that of the circuit part, so the airflow from the optical part to the circuit part can make both parts achieve the purpose of heat dissipation and maintain its normal work.

It should be noted that since the operating temperature of the red laser component is less than 50°C, for example, when the temperature is controlled below 45°C, the liquid cooling method is used, and the surface temperature of the cold row and the surface temperature of the cold head are controlled within the range of 1~2°C. In other words, if the surface temperature of the cold head is 45°C, the surface temperature of the cold row is 43°C to 44°C, where the surface temperature of the cold head refers to the temperature of the contact surface between the cold head and the heat sink of the laser assembly. Specifically, the first fan sucks in the wind at ambient temperature, which is usually 20-25°C, and performs air cooling and heat dissipation on the cold row, reducing the surface temperature of the cold row to 43°C. While the operating temperature of the blue laser component and the green laser component is below 65℃, the temperature of the heat dissipation fin needs to be between 62℃~63℃, and the temperature difference between the temperature of the heat dissipation fin and the heat sink of the laser assembly is in the range of 2~3℃ Inside. It can be seen that the temperature of the cold row is lower than the temperature of the heat dissipation fins, therefore, the cold row is arranged at the front end of the heat dissipation path, and also before the heat dissipation fins in the heat dissipation path. The airflow formed by the rotation of the fan dissipates heat from the cold radiator and then blows it to the heat dissipation fins again, so that the heat dissipation fins can still be dissipated.

In the same way, since the working temperature of the lens is controlled at 85°C and the temperature of the cooling fins is 63°C, which is still lower than the working temperature of the lens, the second airflow after passing through the cooling fins is still cold air compared to the lens. , can use heat dissipation. The operating temperature of the circuit board is generally higher than the operating temperature of the lens. Therefore, the airflow after cooling the lens is still cold air compared to most circuit boards, and can continue to flow through multiple circuit boards for heat dissipation.

In this example, the cold radiator, heat dissipation fins, lenses, and circuit boards have gradually increasing operating temperature thresholds. The above structural layout is also conducive to the design of heat dissipation paths, and the heat dissipation airflow can flow from components with lower operating temperature thresholds to the operating temperature threshold. The higher components can dissipate heat for multiple heat source components in turn in one heat dissipation path, which can not only meet the working heat dissipation requirements of multiple heat source components, but also has high heat dissipation efficiency of the whole machine.

In another specific implementation, in order to enhance the heat transfer coefficient of the heat dissipation fins, the surface of the fins can be structurally improved to increase the heat dissipation area, or to increase the flow velocity of the wind, thereby increasing the heat dissipation capacity.

In the laser projection device provided by the above embodiment, the luminous power range of the red laser component can be 24W~56W, the luminous power range of the blue laser component can be 48W~115W, and the luminous power range of the green laser component can be 12W~28W . Preferably, the luminous power of the red laser component is 48W, the luminous power of the blue laser component is 82W, and the luminous power of the green laser component is 24W. The above three-color lasers all use MCL type laser components. Compared with BANK type lasers, the volume is greatly reduced under the same luminous power output.

From the above description, in the laser projection equipment, the heat dissipation requirement of the light source 100 is the most stringent, and it is the part with relatively low operating temperature control in the whole equipment. Specifically, the working temperature of the red laser assembly is lower than the working temperature of the blue laser assembly and the green laser assembly, which is determined by the light-emitting principle of the red laser. The blue and green lasers are generated using gallium arsenide luminescent material, and the red laser is generated using gallium nitride luminescent material. The red laser has low luminous efficiency and high calorific value. Red laser light-emitting materials also have stricter temperature requirements. Therefore, when dissipating heat for the light source components composed of three-color lasers, it is also necessary to set up different heat dissipation structures according to the temperature requirements of different laser components, which can ensure that the lasers of each color work in a better state and improve the use of laser components. life, and its luminous efficiency is also more stable.

The air-cooled heat dissipation method can control the temperature difference between the hot end and the cold end of the heat source at about 3°C, while the temperature difference control of the liquid-cooled heat dissipation can be more precise and smaller, such as 1~2°C. For red laser components with a lower operating temperature threshold, liquid cooling is used, while for blue and red laser components with relatively high operating temperature thresholds, air cooling is used, which can meet the operating temperature requirements of the red laser. , it can dissipate heat at a lower heat dissipation cost, and it is enough to satisfy a small temperature difference control, so that the speed requirement of the fan can be reduced. However, the component cost of liquid cooling is higher than that of air cooling.

Therefore, in the laser projection device in this example, a mixed heat dissipation method of liquid cooling and air cooling is adopted for the heat dissipation of the light source, which can satisfy the working temperature control of different laser components and is economical and reasonable.

Specifically, referring to FIG. 19 , the metal substrate on the back of the red laser assembly 110 is connected to the cold head through the first heat conducting block 613 , the area of the first heat conducting block 613 is larger than that of the heat conducting surface of the cold head, and the area of the first heat conducting block is also larger than that of the red head The area of the heat transfer surface of the heat sink on the back of the laser assembly 110 . In this way, the heat of the heat sink of the laser assembly can be quickly concentrated and transferred to the cold head, thereby improving the heat conduction efficiency.

In the heat dissipation system structure shown in FIG. 19 , the outlet of the cold head 610 is connected to the inlet of the cold row 611 through a pipe, and the outlet of the cold row 611 is connected to the inlet of the cold head 610 through a pipe. In the liquid cooling circulation system composed of the cold head 610, the cold row 611 and the pipeline, a liquid replenisher 612 is also provided. As mentioned above, the liquid replenisher 612 is used to supplement the cooling liquid for the system circulation, so the liquid replenisher can be set for the entire circulation system. According to the system structure space and other factors, there can be one or more liquid refills, which can be connected with the pump or set close to the cold row.

In this example, the blue laser assembly and the green laser assembly have the same operating temperature control and share a heat sink fin structure. Specifically, as shown in FIGS. 20 and 6C , the heat sinks on the back of the blue laser assembly 120 and the green laser assembly 130 are in contact with the heat pipes 602 through the heat conducting blocks 603 , and the heat pipes 602 extend into the heat dissipation fins 601 . Corresponding to laser components of different colors, for example, corresponding to blue laser components, the thermal conductive block 603 is the second thermal conductive block for the convenience of distinction, and corresponding to the green laser component, the thermal conductive block 603 is the third thermal conductive block. The second heat-conducting block and the third heat-conducting block can be two independent parts, which conduct heat conduction for different laser components respectively, or can be a whole structure, which is convenient for installation, and when the heat dissipation requirements of the two colors of laser components are the same, the Easy to control temperature.

Wherein, the above-mentioned heat pipes are a plurality of heat pipes, and preferably, the number of heat pipes corresponding to the blue and green laser components is the same. In this example, the heat pipe is a straight heat pipe, there are a plurality of heat pipes, and a plurality of through holes are formed in the heat dissipation fin for inserting the plurality of heat pipes. The heat dissipation fins 601 are arranged close to the blue and green laser components. Multiple heat pipes can be directly inserted into the heat dissipation fins without being bent. The straight heat pipes are beneficial to reduce the transmission resistance in the change of gas and liquid inside the heat pipe and improve the heat conduction efficiency.

Through the above-mentioned combined heat dissipation structure, the light source components can be dissipated, thereby ensuring the normal operation of the three-color laser light source components. The light source emits three-color lasers, providing high-quality illumination beams, and projecting a projection image with high brightness and good color. Since the three-color laser components are arranged in different spatial positions, multiple optical mirrors are also required in the cavity of the light source to combine the laser beams in different directions, and perform light processing such as homogenization.

In the laser projection device provided in this embodiment, in the schematic diagram of the optical path of the light source shown in FIG. 16 , a first light combining mirror 106 is provided at the intersection of the blue laser and the green laser, and the first light combining mirror transmits the blue laser , reflecting the green laser light, and a second light combining mirror is provided at the intersection of the combined blue laser, green laser and red laser light, the second light combining mirror reflects the red laser and transmits the blue and green lasers. Output to the light outlet of the light source.

Specifically, the light emitting surface of the blue laser assembly 110 is disposed facing the light outlet of the light source. The green laser light emitted by the green laser component 120 is reflected by the first light combining mirror 106 and then incident on the second light combining mirror 107 , and the blue laser light emitted by the blue laser component 110 is transmitted through the first light combining mirror 106 , and passes through the first light combining mirror 106 . The mirror 107 can combine the blue laser and the green laser to output.

The output direction of the blue laser and the green laser outputted by the first light combining mirror 106 is perpendicular to the output direction of the red laser emitted by the red laser assembly 130, and has an intersection, and a second combining beam is arranged at the intersection of the three beams. The light mirror 107 and the second light combining mirror 107 reflect red laser light and transmit green laser light and blue laser light. The three-color laser beams are combined to form a beam of light that is incident on the homogenizing element 109 , and the light spot is reduced by the condensing lens group 111 , and then exits from the light outlet of the light source.

In the light source structure diagram shown in FIG. 8 , the green laser component 120 and the red laser component 130 are installed side by side on one side of the light source housing, and the blue laser component 110 is installed on the other side of the light source housing 102. These two The sides of the light source housing are in a vertical relationship. The three-color laser components all output rectangular light spots, and are vertically installed on the side surface of the light source housing along the longitudinal direction of the respective rectangular light spots. And the red laser assembly 130 is disposed close to the light outlet of the light source.

In the inner cavity of the light source 100, a plurality of light combining mirrors and a condensing mirror group are also arranged. Specifically, the first light combiner 106 is located between the blue laser assembly 110 and the green laser assembly 120, at the intersection of the two. The second light combining mirror 107 is disposed obliquely toward the light emitting surface of the red laser assembly 130 , reflects the red laser light, and transmits the blue laser light and the green laser light. The first light-combining mirror 106 and the second light-combining mirror 107 are generally arranged in parallel, and are arranged at 45 degrees to the light-emitting surface of the corresponding laser component. The first light combining mirror 106 and the second light combining mirror 107 are supported and fixed on the bottom surface of the light source housing 102 by the base, and considering the assembly tolerance, the angles of the first light combining mirror and the second light combining mirror are also It can be fine-tuned, such as within plus or minus 3 degrees.

The second light combining mirror 107 is disposed close to the condensing mirror group 111 , and outputs the combined three-color laser beams to the condensing mirror group 111 .

Wherein, the first light combining mirror is a reflecting mirror, and the second light combining mirror is a dichroic plate.

In addition, the light reflectivity of the first light combining mirror and the second light combining mirror are both greater than their light transmittances. For example, the light reflectivity of the two light combining mirrors can reach 99%, and the transmittance is usually 95%-97%.

The three-color laser components provided in this example are all MCL-type lasers. As shown in Figure 14, the MCL laser includes multiple light-emitting chips packaged on a metal substrate. Due to different light-emitting principles, the light-emitting power of light-emitting chips of different colors It is also different. For example, the luminous power of green chips is about 1W per chip, while the luminous power of blue chips is more than 4W per chip. When the above three-color lasers are arranged with the same number of chips, for example, they all use the 4X6 package type, the overall luminous power is also different. The luminous power of the blue laser component, the luminous power of the red laser component is less than the luminous power of the blue laser component.

Meanwhile, in the above embodiment, the red laser component, the blue laser component and the green laser component are packaged in the same array of light-emitting chips, for example, a 4×6 array. However, due to the difference in the light-emitting principle of the red laser, as shown in Figure 22, there will be two light-emitting points at one light-emitting chip, which makes the divergence angles of the red laser in the fast-axis and slow-axis directions compared with those of the blue laser and the green laser. In the process of optical path transmission, for the same optical lens, the red laser has a certain light-receiving range or better light processing performance in a certain angle range due to the large divergence angle of the red laser, so that the red laser passes through. The longer the optical path or optical path, the more serious the degree of divergence, and the lower the light processing efficiency of the rear optical lens for the red laser. Although the luminous power of the red laser component is greater than that of the green laser, the optical loss rate of the red laser is greater than that of the green and blue lasers after passing through the same length of the optical path.

In the light source structure shown in FIG. 8 , the light-emitting surface of the blue laser assembly 110 faces the first light outlet 103 of the light source. After the blue laser is output along the light-emitting surface of the blue laser assembly, it is transmitted twice and passes through the homogenizing element. 109 and the condensing lens group 111 then exit from the first light exit port 103 . As for the green laser, it will be reflected once and then transmitted once, and then enters the homogenizing element 109 and the converging lens group 111 and exits from the first light exit port 103 . The red laser light enters the homogenizing element 109 and the condensing mirror group 111 after being reflected once, and exits from the first light exit port 103 . It can be seen that before output from the first light outlet of the light source, the light path of the red laser is shorter than that of the blue laser and the green laser, so that the light loss of the red laser during the transmission of the light path can be reduced. And, without considering the influence of the light path on the light loss, after the red laser is reflected by the second light combiner, the light energy can reach about 99%*1=99%. It should be noted that here for the red laser light The calculation of energy efficiency does not take into account the large divergence angle of the red laser and the presence of large-angle light loss, and only considers the influence of the transmittance of the optical lens.

While the blue laser is transmitted twice, when only considering the effect of transmittance on light loss, the light energy output by the green laser from the second light combiner can reach about 97%*97%=94%, and the green laser is transmitted once With one reflection, the light energy output from the second combiner mirror can reach about 99%*97*=96%. In practical applications, the luminous power of the blue laser can be higher, and the visual function of the human eye for blue is relatively low. Therefore, the red laser has the shortest path, and the loss of transmittance through the lens is also the smallest, but the red laser has the largest divergence angle in the transmission optical path, which is easy to lose. Based on the above-mentioned laser light source layout, under the different optical characteristics of each color laser, the loss of each color laser beam in the transmission process can be well balanced, so that the power ratio of the three color lasers is close to the preset value, and there will be no obvious imbalance. , it is also beneficial to achieve the color ratio and desired white balance in line with the theoretical design. However, when the three-color laser beams are combined and output from the third beam combining mirror, the light paths experienced by the three are the same, and it is easy to achieve the same light loss.

The above-mentioned lasers are arranged in a flat and elongated shape, which is relatively regular, which is beneficial to the structural design, and can reserve a regular space for the casing, which is convenient for arranging the heat sink.

The above-mentioned laser components all use MCL-type laser components. Compared with the traditional BANK-type laser components, the volume of the MCL-type laser components is significantly smaller. Therefore, in this embodiment, the light source of the laser projection equipment shown in FIG. 1 and FIG. 8 is used. , its structural volume is significantly smaller than the traditional use of BANK laser components, so that more space can be reserved near the light source, which provides convenience for heat dissipation design, such as the radiator, the placement of the fan will be more convenient. In order to be flexible, and it is also possible to provide structures such as circuit boards, it is also beneficial to reduce the length of the whole machine structure in a certain direction, or the volume of the whole machine.

As a modification of FIG. 16 , the same as the optical path shown in FIG. 16 , the positions of the blue laser assembly and the green laser assembly can also be exchanged. For example, as shown in FIG. 17 , the green laser assembly 120 is transmitted through the first light combiner. 106, the blue laser component 110 is reflected by the first light combining mirror 106, so, according to the above-mentioned transmittance calculation, the light energy loss of the green laser is 1-97%*97%=6%, and the The light energy loss is 1-99%*97%=4%, and by increasing the duty ratio of the green primary color in the entire light-emitting cycle, the brightness of the green primary color light can also not be reduced. Therefore, the overall light loss rate of the two can be regarded as almost the same.

In the above-mentioned embodiments, by arranging the red laser component close to the light outlet of the light source, the blue and green lasers respectively pass through the turning optical paths and then merge with the red laser, and the red laser has the shortest optical path, which can reduce the light path of the red laser. The transmission light loss, and the red laser is only reflected by the optical element once, the blue laser and the green laser are respectively subjected to multiple transmission and reflection treatments, specifically, the blue laser is transmitted twice, and the green laser is transmitted once and reflected once. Then output from the light outlet of the light source. Therefore, the loss of the red laser in the transmittance of optical components is correspondingly the lowest. Therefore, it can ensure that the light loss of the red laser before the beam is reduced as much as possible, which is conducive to maintaining the ratio of the beam power and color of the three-color light source, and making the system white balance. Close to the theoretical setting value to achieve higher projected picture quality.

Referring to Fig. 8, Fig. 16, Fig. 17, the light source in the application embodiment of the above-mentioned laser projection equipment, after the three-color laser is combined by the light combining mirror, it also passes through the homogenizing element and the condensing lens group to homogenize and condense the beam. processing, so as to improve the light collection efficiency and homogenization efficiency of the light-receiving element in the subsequent optical engine.

Specifically, as shown in FIG. 8 , FIG. 16 , and FIG. 17 , the light source 100 further includes a homogenizing element 109 and a condensing lens group 111 . The homogenizing element 109 is disposed between the second light combining mirror 107 and the condensing mirror group 111 . Specifically, the homogenizing element can be a diffusion sheet with regularly arranged microstructures, as shown in FIG. 25 . The microstructure of the commonly used diffuser is random and irregular. The homogenized diffuser used in the light source structure uses a regularly arranged microstructure, similar to the principle of beam homogenization by a fly-eye lens, which can convert the energy of the laser beam. The distribution changes from a Gaussian shape to the shape shown in Figure 26. As shown in Figure 26, the energy near the central optical axis of the laser is greatly weakened and becomes smooth, and the divergence angle of the laser beam also increases, so that the energy is homogenized. The effect is much better than the commonly used diffuser with irregularly arranged microstructures.

The above-mentioned homogenizing diffusion sheet can be provided with microstructures arranged regularly on one side, or can be provided on both sides.

After being homogenized by the above-mentioned homogenizing and diffusing sheet, the laser beam passes through the condensing lens group to reduce the spot size. On the one hand, homogenizing the high-energy laser beam first can reduce the impact on the uneven energy distribution of the rear components; The difficulty of homogenizing again.

In addition, the above-mentioned homogenizing element 109 can also be a two-dimensional diffractive element, which can also achieve a better homogenizing effect.

In this example, the converging lens group includes two convex lenses, such as a combination of a biconvex lens and a convex-concave lens. The above two lenses are spherical lenses. Of course, aspherical lenses can also be used, but spherical lenses are both in molding and precision control. It is easier and cheaper than aspherical lenses. In this example, the condensing lens group is used to condense the light beam, and the focal point of the condensing lens group is set at the light-receiving port of the rear light-receiving element, that is, the focal plane of the converging lens group is located at the light-incident surface of the light-receiving element, The light-receiving efficiency of the light-receiving element is improved.

As shown in FIG. 8 , the condenser lens group is located at the first light outlet 103 of the light source housing. Specifically, the rear lens or the entire lens group in the condenser lens group can be installed at the first light outlet 103, and the condenser lens The group 111 and the casing around the first light outlet 103 are filled with sealing members, such as sealing rubber rings. In this way, while the condensing lens group is fixed, the air-tight sealing of the inner cavity of the light source can also be maintained, so as to prevent dust particles and the like from being brought in from the first light outlet, which is used as a light-transmitting window to exchange with the external airflow. Moreover, directly fixing the condenser lens group at the position of the first light outlet is also beneficial to shorten the light path and reduce the volume of the light source housing.

The light beam in the convergent state output from the first light outlet of the light source is finally collected by the light receiving part of the light path of the optomechanical illumination. As shown in FIG. 23 , a schematic diagram of the principle of the optical path, in this example, the light receiving component 250 is a light pipe. The light pipe has a rectangular light entrance surface and a light exit surface. The light guide serves as both a light receiving part and a light homogenizing part. The light incident surface of the light pipe is the focal plane of the condensing lens group 111 , and the condensing lens group 111 inputs the condensed light beam into the light pipe 250 . Since a homogenizing diffuser is arranged in the optical path at the front end, a better three-color mixing and homogenizing effect can be achieved by homogenizing the light guide here, and the quality of the illumination beam is improved.

Since the light source is a pure three-color laser light source, speckle is a unique phenomenon of the laser. In order to obtain a higher display quality of the projected image, the three-color laser needs to be dissipated. In an example, a diffusing wheel 260, that is, a rotating diffusing sheet, is further disposed between the condensing lens group 111 and the light receiving member 250. The diffusing wheel 260 is located in the condensing light path of the condensing lens group 111 , and the distance between the surface of the diffusing wheel 260 is about 1.5-3 mm from the light receiving part 250 to the light incident surface of the light pipe. The diffuser wheel can diffuse the beam in the convergent state, increase the divergence angle of the beam, and increase the random phase. And, because the human eye has different speckle sensitivity to different color lasers, the diffusing wheel can be divided into divisions, such as a first division and a second division, the first division is used to transmit red laser light, and the second division is used to transmit blue laser light and green laser, the divergence angle of the first partition is slightly larger than that of the second partition. Or, it is divided into three partitions, corresponding to red laser, green laser, and blue laser respectively. Among the above three partitions, the divergence angle of the red laser partition is related as follows: the red laser partition has the largest divergence angle, and the blue laser partition has the largest divergence angle. Minimum angle. When the diffusing wheel has corresponding divisions, the rotation period of the diffusing wheel may be consistent with the period of the light source. Generally, when the diffusing wheel is a diffusing sheet, its rotation period is not particularly limited.

The light pipe has a certain light-receiving angle range. For example, the light beam within the range of plus or minus 23 degrees can enter the light pipe and be used by the rear lighting light path, while other large-angle light beams become stray light and are blocked out, resulting in light loss. The light-emitting surface of the diffusing wheel is arranged close to the light-entering surface of the light guide, which can increase the light quantity of the diffused laser beam collected into the light guide, and improve the light utilization rate.

In addition, the said light receiving member may be a fly-eye lens member.

And, as mentioned above, since the homogenizing and diffusing sheet 109 is disposed in the optical path at the front end, the light beam of the light source is condensed by the condensing lens group 111 after homogenizing, and incident on the diffusing wheel 260 . The laser beam first passes through a stationary diffuser, and then passes through a moving diffuser. In this way, on the basis of the beam homogenization by the static diffuser, the laser beam is diffused and homogenized again, which can enhance the homogenization of the laser beam. The effect is to reduce the energy ratio of the beam near the optical axis of the laser beam, thereby reducing the degree of coherence of the laser beam, and the speckle phenomenon presented by the projection image can be greatly improved.

In the light source provided by the above embodiment, the light source beam is incident on the light pipe to receive light and homogenize again, and the applicant measures the light spot distribution on the light entrance surface of the light pipe to show a relatively obvious color boundary phenomenon between the inner and outer circles. For example, the converging light spot is circular, the outermost circle is red, and inwards are purple, blue and other concentric apertures. As shown in Figure 27. Through research, it is found that, as mentioned above, the divergence angle of the fast and slow axes of the red laser component is larger than that of the blue laser and the green laser due to the different light-emitting principles. Although in this example, the three-color laser components are arranged in an array with the same number of chips, and the dimensions are the same in volume appearance, but due to the characteristics of the red laser itself, the spot size of the red laser beam during transmission is larger than that of the blue laser beam. Spot size of laser and green laser. This kind of light already exists when the three-color combined light is performed, and with the increase of the transmission distance of the optical path, its divergence angle increases faster than that of another color laser, so that although the three-color combined light will be homogenized, Condensation, and possibly re-diffusion and homogenization through a rotating diffuser, but there is always a red laser with a larger spot size. The test spot on the light entrance surface of the light pipe also showed this phenomenon.

In order to improve the coincidence of the three-color laser spots, the length of the light guide can be increased to improve the mixing and homogenization effect, but this will increase the length of the optical path and increase the volume of the structure.

In this example, a solution is proposed. Specifically, on the basis of the optical path schematic diagrams provided in the aforementioned Figures 16 and 17, as shown in Figure 24, a diffuser is set in the combined optical path of the blue laser and the green laser. In the plate 108, the blue laser and the green laser are diverged first and then combined with the red laser beam. The diffusing sheet 108 is disposed in the light path between the first light combining mirror 106 and the second light combining mirror 107 . Of course, stationary diffusers may also be provided for the blue laser and the green laser, for example, in the light paths between the light-emitting surfaces of the two-color laser components and the corresponding light combining mirrors.

By arranging a diffuser in the light path of the blue laser and green laser, the blue laser and green laser can be expanded, for example, a diffusion angle of 1 degree to 3 degrees is set. After passing through the diffuser, the beam expands The blue and green lasers are then combined with the red laser. At this time, the spot sizes of the three-color lasers are the same, and the spot overlap is improved. The three-color light spot with a high degree of coincidence is also conducive to the homogenization and dissipation of the subsequent light path, and the beam quality is improved.

The laser emitted by the laser is linearly polarized light. In the process of emitting red laser, blue laser and green laser, the resonator oscillation direction is different, resulting in linearly polarized red laser light, blue laser linearly polarized light, and green laser linearly polarized light. The polarization direction is 90 degrees, the red laser is P-ray polarized light, and the blue and green lasers are S-ray polarized light.

In the above embodiments, in the light sources shown in Fig. 1 and Fig. 8, a red laser component and a blue laser component are used, and the polarization direction of the green laser component is 90 degrees, wherein the red laser is P light, the blue and Green laser is S light. The three-color beams projected by the laser projection equipment have different polarization directions.

In practical applications, in order to better restore color and contrast, laser projection equipment is usually equipped with a projection screen with high gain and contrast, such as an optical screen, which can better restore high-brightness and high-contrast projection images.

An ultra-short-focus projection screen is shown in Figure 5, which is a Fresnel optical screen. Along the incident direction of the projection beam, it includes a base material layer 401 , a diffusion layer 402 , a uniform medium layer 403 , a Fresnel lens layer 404 and a reflection layer 405 . The thickness of the Fresnel optical screen is usually between 1 and 2 mm, and the thickness ratio occupied by the base material layer 401 is the largest. The substrate layer also serves as the support layer structure of the entire screen, and has a certain light transmittance and hardness. The projection beam first transmits through the base material layer 401 , then enters the diffusion layer 402 for diffusion, and then enters the uniform medium layer 403 . The light beam is transmitted through the homogeneous medium layer 403, enters the Fresnel lens layer 404, and the Fresnel lens layer 404 converges and collimates the light beam. Layer 403, diffuser layer 402, and substrate layer, 401 and incident into the user's eye.

During the research and development process, the applicant found that the ultra-short-focus projection image using the above-mentioned three-color laser light source will have partial color cast, resulting in uneven chromaticity such as "color spots" and "color blocks". One of the reasons for this phenomenon is that in the currently used three-color laser, the polarization directions of the laser beams of different colors are different, and there are usually multiple optical lenses in the optical system, such as lenses, prisms, and the optical lenses themselves. There is a difference between the transmittance and reflectivity of P polarized light and S polarized light. For example, the transmittance of optical lenses for P light is greater than that for S light. On the other hand, because of the screen material structure, with the With the change of the incident angle of the ultra-short-focus projection beam, the ultra-short-focus projection screen itself will show obvious changes in the transmittance and reflectivity of the beam with different polarization directions, as shown in Figure 6, for the red projection beam, when the projection angle When it is about 60 degrees, after testing, the reflectivity of the projection screen to the red projection beam of the P light type and the reflectivity of the red projection beam of the S light type differs by more than 10 percentage points, that is, the ultra-short focus projection screen is sensitive to P light. The reflectivity is greater than the reflectivity of the S light, so that more P light will be reflected by the screen into the human eye, while the S light reflected by the screen into the human eye will be relatively reduced. This kind of light of the same color with different polarization directions The difference in transmission and reflection also exists when the projection beam is of other colors, and when the three primary colors of light are in different polarization states, after passing through the above-mentioned projection optical system and projection screen, especially the projection screen has relatively obvious difference in transmission and reflection, It will cause the luminous flux of different colors of light reflected by the screen to enter the human eye to be unbalanced, which will eventually lead to a color cast in a local area on the projection screen, which is especially obvious when displaying color images.

In order to solve the above problems and phenomena, improvements are made on the basis of the light sources provided in the above embodiments, and another light source structure embodiment is proposed.

In this embodiment, the blue laser component and the green laser component are arranged adjacent to each other, and a phase retarder is arranged in the output paths of the blue laser and green laser and before the third light combining mirror is incident to change the blue laser and the green laser. The polarization direction of the laser is the same as that of the red laser, which solves the color cast phenomenon of the projection screen caused by different polarization directions.

First, let's introduce the working principle of the phase retarder. The phase retarder is a wavelength corresponding to a certain color. The thickness of the crystal growth affects the degree of phase change of the transmitted beam. In this example, the phase retarder is a half-wave plate, also known as a λ½ wave plate, which can convert the wavelength corresponding to the color wavelength. The phase of the light beam is changed by π, that is, 180 degrees, and the polarization direction is rotated by 90 degrees, such as changing P light into S light, or changing S light into P light. As shown in Figure 28, the wave plate is a crystal, the crystal has its own optical axis W, located in the plane where the wave plate is located, and the wave plate is arranged in the optical path, perpendicular to the optical axis O of the light source, so the optical axis W of the wave plate and the light source are The optical axes O are perpendicular to each other.

As shown in Figure 29, a coordinate system is established with the optical axis W of the wave plate, and the coordinate system formed by the P-polarized light along the optical axis W and the direction perpendicular to the optical axis W has components Ex, Ey, where Ex, Ey can both utilize light waves formula to represent. The P light can be regarded as the spatial synthesis of the two-dimensional waves of the components Ex and Ey.

When the P light passes through the wave plate, the phase changes by π, that is, 180 degrees. The phase constants of Ex and Ey both have a change of π. For the light wave at a certain moment in the original polarization direction, b0, c0, and a0 are carried out by 180 degrees. After the phase is changed, after the light waves of the two direction components are superimposed, the polarization position of the spatial position changes, forming b1, c1, a1, thus becoming the light in the S polarization direction. The above-mentioned spatial position changes of b0, c0, a0 and b1, c1, a1 are only for illustration.

After passing through the half-wave plate, the light in the original P-polarization direction becomes the light in the S-polarization direction. As shown in Figure 30, the two polarization directions are perpendicular to each other.

Based on the above description, as shown in the schematic diagram of the optical path shown in FIG. 32 , phase retarders of corresponding wavelengths are respectively arranged in the light exit paths of the blue laser component and the green laser component, and the phase retarder is specifically a half-wave plate. In this example, the central wavelength of the blue laser is about 465 nm, and the central wavelength of the green laser is about 525 nm. When the schematic diagram of the optical path shown in FIG. 32 is shown, the half-wave plate 121 is located in the light-emitting path of the blue laser. Corresponding to the central wavelength setting of the blue laser, the half-wave plate 131 is located in the light-emitting path of the green laser, and it is set corresponding to the central wavelength of the green laser, so that the polarization directions of the green laser and the blue laser can be changed by 90 degrees. becomes P light.

Based on the above-mentioned optical path principle, in a specific implementation, the above-mentioned half-wave plate can be arranged in the inner cavity of the light source, between the inner side of the light source housing and the light combining mirror corresponding to the laser assembly, by arranging a lens base on the bottom surface of the light source housing , to fix the half-wave plate.

Alternatively, the half-wave plate may be disposed inside the window provided for the laser assembly on the light source housing, for example, fixed inside the window by gluing or fixing a bracket.

Alternatively, the half-wave plate can be arranged between the laser component and the outside of the light source housing window. For example, the half-wave plate is mounted or fixed on the outside of the window, and the laser component (including the fixing bracket) is then installed on the outside of the window through the fixing bracket. position.

Alternatively, when sealing glass is provided at the window glass, the half-wave plate may be located between the sealing glass and the light-emitting surface of the laser assembly. As shown in the exploded view of the structure of the laser assembly shown in FIG. 13 , there is a support table (not shown in the figure) on the front of the light-transmitting window 10211 of the fixing bracket of the laser assembly, and the half-wave plate 140 can be fixed on the support table by gluing , there is also an accommodating groove around the bearing platform for accommodating the first sealing member 1051 . FIG. 10 shows a schematic diagram of the half-wave plate installed on the front of the fixing bracket, wherein the half-wave plate 140 is installed at the position of the light-transmitting window 10211 of the fixing bracket, and is glued and fixed through the dispensing grooves around it. The length and width of the half-wave plate 140 are respectively 25-30 mm and 21-28 mm; the length and width of the light transmission window of the fixed bracket are respectively 20-24 mm and 18-20 mm. For example, in an embodiment, the half-wave plate Select 30mm*28mm, and the size of the light transmission window is 24mm*20mm.

After the half-wave plate 140 is fixed on the fixed bracket 104, the MCL laser assembly mounted on the fixed bracket and the fixed bracket 104 are installed on the installation position of the window 1021 of the light source housing 102. As mentioned above, the light source The installation position of the window 1021 of the housing is further provided with a second accommodating groove for accommodating the second sealing member 1052, and the sealing glass 105 is sandwiched by the first sealing member 1051 and the second sealing member 1052 on the laser assembly. Based on the above structure, after the light beam of the laser assembly is emitted from the light-emitting chip, it sequentially passes through the half-wave plate 140 and the sealing glass 105 and then enters the light source cavity through the window 1021 of the light source housing.

In the above light source structure, half-wave plates of corresponding colors are installed on the fixing brackets of the blue laser component and the green laser component, so that after passing through the corresponding half-wave plates, the polarization polarity of the beam changes by 90 degrees. When the green laser is incident on the first light combining mirror, it is already P light, and when the blue laser is incident on the first light combining mirror, it is already P light, so the blue laser and the green laser are combined by the first light combining mirror and output. The light beams are all P-polarized light, which is the same as the polarization direction of the red laser. The second light combining mirror combines the three-color beams with the same polarization directions and outputs them, and then goes through the homogenization, beam reduction and other processing, and enters the light path of the optical machine. , reflected by DMD into the lens, and projected onto the screen by the lens for imaging. Due to the consistent polarization directions of the three colors, the phenomenon of uneven chromaticity such as "color spots" and "color blocks" in the projected image can be eliminated or greatly alleviated.

As a modification of the above-mentioned embodiment, in this example, the blue laser and the green laser are combined first and then combined with the red laser. At this time, the half-wave plate can also be arranged after the blue laser and the green laser are combined. In the light path before combining with the red laser. Specifically, as shown in FIG. 33 , which provides another schematic diagram of the optical path of the light source, the half-wave plate 141 can be arranged between the first light combining mirror 106 and the second light combining mirror 107 , and the transmission from the first light combining mirror 106 The combined beam of the outgoing blue laser and green laser. Based on the above-mentioned optical path principle, the green laser light and the blue laser light output S-polarized light respectively, the green S light is incident on the first light combining mirror 106 and is reflected, the blue S light is incident on the first light combining mirror 106 and transmitted, and the first light combining mirror 106 is transmitted. A light combiner 106 combines the blue laser and green laser, both of which are S light, and passes through the half-wave plate 141. The half-wave plate 141 changes the polarization directions of the green laser and the blue laser, and then enters the second light combiner. 107.

Specifically, the half-wave plate 141 can be set for the wavelength of one of the colors, for example, for the wavelength of the green laser. After the green laser passes through the half-wave plate, the polarization direction is rotated by 90 degrees, changing from the original S light to P light. After the blue laser passes through the half-wave plate, since the wavelength of the half-wave plate is not set corresponding to the blue wavelength, the polarization direction of the blue laser is not 90 degrees, but close to the P polarization direction. Low, the sensitivity to blue is low, and the visual discomfort is more obvious when there is a color cast such as red and green. Alternatively, the half-wave plate 141 can also be set for the middle value of the blue and green central wavelengths, so that the polarization directions of the green laser and the blue laser are not changed by 90 degrees, but are close to 90 degrees, although the blue laser and the green laser are not changed by 90 degrees. None of the lasers is deflected from S light to P light, but neither is the original S light polarization state. It can also improve the consistency of the light processing process of the entire system for the three primary colors of red, green and blue, and can improve the local area presentation on the projection screen. The technical problems of uneven chromaticity such as "color spots" and "color blocks" will not be repeated.

In the above example, the half-wave plate 141 can be fixed by a fixing base disposed on the bottom surface of the light source housing.

In an optical system, for different wavelengths, the same optical lens has the same transmittance to P light and S light of different wavelengths, and the same reflectivity to P light and S light. The optical lenses here include various optical lenses in the entire laser projection device, such as the condensing lens group, the lens group in the illumination light path in the optomechanical section, and the refractive lens group in the lens section. Therefore, when the light beam emitted by the laser light source passes through the entire projection optical system, this difference in transmission and reflection is the result of the superposition of the entire system, which will be more obvious.

Before adding a half-wave plate, especially when the primary color light is P light and S light polarized light, whether it is the optical lens of the optical system or the projection screen, their selective transmission of P light and S light is more obvious. For example, with the different incident angles of the projection beam, the transmittance of the projection screen for P light (red light) is significantly greater than that for S light (green light and blue light), which results in a partial projection of the screen. The problem of uneven chromaticity, that is, the phenomenon of "color spots" and "color blocks" appearing on the screen.

In the multiple embodiments provided above, by setting half-wave plates in the light exit paths of blue laser and green laser, when half-wave plates with corresponding wavelengths are respectively set for blue laser and green laser, the targeted blue laser The polarization directions of both the color laser and the green laser can be changed by 90 degrees. In this example, the polarization direction of the S light is changed to the polarization direction of the P light, which is consistent with the polarization direction of the red laser. When the projection screen is reflected into the human eye, the transmittance of the blue laser and green laser that become P-polarized light in the optical lens is equivalent to the transmittance of the red laser that is P light, and the consistency of the light processing process is close to , and the difference in the reflectivity of the projection screen to the three-color laser is also reduced, and the consistency of the light processing process of the entire projection system for the three-color primary light is improved, which can fundamentally eliminate the "color spots" and "color spots" that appear in local areas on the projection screen. The color cast phenomenon of "block" improves the display quality of the projected picture.

And, when a half-wave plate is set in the combined light path of the blue laser and the green laser, the polarization direction of one of the green laser or the blue laser can be changed by 90 degrees, or the polarization direction of the two colors of lasers can be changed. Both are not changed to 90 degrees, but both are close to 90 degrees. It can also reduce the polarization difference with the red laser P light. Based on the above principle, it can also improve the consistency of the light processing process of the entire system for the three primary colors of red, green and blue, and can improve the "color" presented in the local area on the projection screen. Technical problems such as uneven chromaticity such as spots” and “color blocks”.

And, since the transmittance of the optical lens to P-polarized light in the optical system is usually greater than that of S-polarized light, and the projection screen applied in this example also has a greater reflectance to P-polarized light than to S-polarized light. Therefore, by converting the S-polarized blue laser and green laser into P-polarized light, so that the red, green, and blue lasers are all P light, the light transmission efficiency of the projection beam in the entire system can also be improved, The brightness of the entire projection picture can be improved, and the quality of the projection picture can be improved.

In order to solve the technical problems of uneven chromaticity such as "color spots" and "color blocks" appearing on the above-mentioned projection screen, this embodiment provides a laser projection device, which applies the light source part as shown in FIG. 34 . In this example, a half-wave plate corresponding to the red wavelength is provided before the red laser beam is combined with the blue and green laser beams. For example, the half-wave plate 151 is disposed between the red laser assembly 110 and the second light combining mirror 107 .

For the setting scheme of the half-wave plate, please refer to the scheme of setting the half-wave plate for the blue laser and the green laser respectively in the previous embodiment.

For example, the half-wave plate can be arranged in the inner cavity of the light source, in the light path between the inner side of the light source housing and the third light combining mirror, and the half-wave plate can be fixed by arranging a lens base on the bottom surface of the light source housing.

Alternatively, the half-wave plate may be arranged inside the window provided for the red laser component on the light source housing, for example, fixed inside the window by gluing or fixing a bracket.

Alternatively, the half-wave plate can be arranged between the red laser component and the outside of the light source housing window. For example, the half-wave plate is mounted or fixed on the outside of the window, and the laser component (including the fixing bracket) is then installed on the outside of the window through the fixing bracket. on the installation position.

Alternatively, when sealing glass is provided at the window glass, the half-wave plate may be located between the sealing glass and the light-emitting surface of the laser assembly. The specific installation method can also refer to the introduction in FIG. 13 , which will not be repeated here.

The half-wave plate 151 corresponds to the wavelength setting of the red laser. Similarly, the polarization direction of the red laser can be rotated by 90 degrees through the half-wave plate, and the red laser can be changed from P-polarized light to S-polarized light.

It should be noted that the above-mentioned solution of setting a half-wave plate for the red laser is also applicable to the optical path schematic diagrams shown in FIG. 16 , FIG. 17 , FIG. 23 , and FIG. 24 of the present invention.

In the above example, by setting a half-wave plate in the output light path of the red laser, the red laser that was originally P-polarized light is converted into S-polarized light, which is consistent with the polarization directions of the blue laser and green laser, so that the three-color light of the system is The polarization directions are the same. Referring to the principle description of the previous embodiment, the transmittance of the projection optical system to the red laser, blue laser and green laser that are both S-polarized light is smaller than that of the polarized light with different polarization directions. The reflectivity of the focal projection screen to the three-color light that is also S-polarized light is basically the same, so that the light processing consistency of each primary color is improved, which can eliminate or improve the "color spots" and "color blocks" displayed on the projection screen. uniform phenomenon.

And, in the above-mentioned embodiments, the laser light-emitting surface is rectangular, correspondingly, the phase retarder is correspondingly arranged in the light output path of one color or two colors, and its shape is also a rectangle, wherein the laser rectangular light-emitting area is The long side and the short side are respectively parallel to the long side and the short side of the rectangular light-receiving area of the retarder.

Due to the high energy of the laser beam, optical lenses, such as lenses and prisms, will be accompanied by temperature changes during the working process, and the optical lenses will form internal stress during the manufacturing process. Refraction, and this stress birefringence will cause light beams with different wavelengths to have different phase delays, which can be regarded as secondary phase delays. Therefore, in the actual optical path, the phase change of the beam is based on the superimposed effect of the stress birefringence of the half-wave plate and the optical lens, and the inherent retardation caused by the optical lens will vary according to the system design. When the technical solutions of the above-mentioned embodiments of the present application are applied, it is preferable to correct the secondary phase delay caused by the actual system, so as to approach or reach the theoretical value of changing the polarization direction of the beam by 90 degrees.

The half-wave plate has an optical axis in the plane where the flat plate is located. As shown in Figure 28, the optical axis W of the half-wave plate is spatially perpendicular to the optical axis O of the system, and the optical axis of the half-wave plate is parallel to the length of the half-wave plate. side or short side. When the solution of the above embodiment is specifically applied, as shown in FIG. 31 , the half-wave plate is set as follows: along the long side or short side of the rectangular half-wave plate, the half-wave plate is rotated according to a preset angle, such as C degrees, such as Shown in dashed line in the figure. After the above angle deflection, the optical axis of the half-wave plate is also deflected by about positive and negative C degrees, so that the change of the beam phase is about 180 degrees ± 2 C degrees, and then superimposed with the secondary phase delay of the system optical lens , and finally the polarization direction of the beam is changed at about 90 degrees, which is close to the theoretical design value. In the foregoing multiple embodiments of the present application, C can take a value of 10.

In one or more of the above embodiments, for the three primary colors of light with different polarization directions of the laser projection light source, by setting half-wave plates in the light output paths of one color or two colors in the light source of the laser projection equipment, changing the corresponding transmittance. The polarization direction of one or two colors of light that has passed through is consistent with the polarization directions of other colors, and the polarization polarities of the three primary colors of light output by the laser projection device are the same, so that the laser beam emitted by the light source of the laser projection device passes through the same direction. When the optical imaging system is set and reflected into the human eye through the projection screen, the transmittance of the optical system to the three-color laser is close, and the difference in the reflectance of the projection screen to the three-color laser is also reduced. The consistency of the light processing process is improved, which can fundamentally eliminate the phenomenon of uneven chromaticity such as "color spots" and "color blocks" in local areas on the projection screen, and improve the display quality of the projection screen.

Those skilled in the art can understand that when solving the problem of displaying the projected image caused by the different polarization directions of the three primary colors of light and the obvious difference in the transmittance of the light with different polarization directions of the projection screen in the above-mentioned embodiments, the red laser is used as the P light, blue and green lasers are illustrated as S light, and are not limited to this combination of P light and S light. Those skilled in the art can combine the color and polarization direction of the actual light beam with the embodiment of the present application. The core principle of the invention can be adaptively changed, and the above-mentioned changes should also fall within the protection scope of the present application.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. scope.

Claims (12)

1. A laser projection device, characterized in that, comprising a complete machine housing, a light source, an optical machine and a lens; The light source includes a red laser component and a green laser component installed in parallel, and a blue laser component perpendicular to the red and green laser components; A first light combining mirror is arranged at the intersection of the blue laser and the green laser, the first light combining mirror transmits the blue laser and reflects the green laser, And, a second light combining mirror is arranged at the intersection of the combined blue laser, green laser and red laser, the second light combining mirror reflects the red laser and transmits the blue and green lasers, and outputs the three-color lasers to the light source light exit. 2 . The laser projection device according to claim 1 , wherein the light reflectivity of the first light combining mirror and the second light combining mirror are both greater than their light transmittances. 3 . 3 . The laser projection device according to claim 1 , wherein the luminous power of the green laser component is smaller than the luminous power of the red laser component and the blue laser component. 4 . 4. The laser projection device according to claim 2 or 3, wherein the spot size of the red laser light reaching the second light combining mirror is larger than the spot size of the blue laser light and the green laser light. 5 . The laser projection device according to claim 1 , wherein a homogenizing element and a condensing lens group are arranged in sequence in the light path from the second light combining mirror to the light outlet of the light source. 6 . 6. The laser projection device according to claim 2 or 3, wherein a diffuser is further provided in the light path from the first light combining mirror to the second light combining mirror, for diffusing and transmitting the Green and blue lasers. 7 . The laser projection device according to claim 5 , wherein the homogenizing element is a diffuser with regularly arranged microstructures, or the homogenizing element is a two-dimensional diffractive element. 8 . 8 . The laser projection device according to claim 1 or 5 , wherein the light beams of the three-color light source exit from the light source light outlet and enter the light receiving part through a diffusing wheel. 9 . 9. The laser projection device according to claim 1, wherein a half-wave plate is further provided in the optical path from the first light combining mirror to the second light combining mirror; The half-wave plate is set corresponding to the wavelength of the green laser, or the half-wave plate is set corresponding to the wavelength between the green laser and the blue laser. 10 . The laser projection device according to claim 1 , wherein half-wave plates are respectively provided in the light paths between the light-emitting surfaces of the blue laser components and the green laser components and the first light combining mirror. 11 . , the half-wave plates are respectively set corresponding to the blue laser wavelength and the green laser wavelength. 11 . The laser projection device according to claim 1 , wherein the polarization directions of the blue laser and the green laser are the same, and the polarization directions of the red laser and the two color lasers are different. 12 . 12. The laser projection device according to any one of claims 1 to 10, wherein the luminous power of the red laser component is 24W to 56W, the luminous power of the blue laser component is 48W to 115W, and the green laser component has a luminous power of 48W to 115W. The luminous power of the laser components is 12W~28W.

Images