JP2023136540A - projector - Google Patents

Abstract

To provide a projector that enables a reduction in size and thickness as a whole while avoiding deterioration in an image.SOLUTION: The projector includes: a plurality of display elements 11r, 11g, and 11b for emitting light having mutually different wavelength bands; a plurality of diffraction elements 21r, 21g, and 21b (first diffraction element DE1) that diffracts each color light GLr, GLg, and GLb emitted from the plurality of display elements 11r, 11g, and 11b; a second diffraction element DE2 that is a synthetic diffraction element for synthesizing each color light GLr, GLg, and GLb from the plurality of diffraction elements 21r, 21g, and 21b; a projection optical system 30 that projects image light GL as synthetic light generated by the second diffraction element DE2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a small-sized projector using a hologram.

An optical unit that can be applied to a projection type display device is known as an optical unit that combines light from three panels equipped with light emitting elements using a dichroic prism that includes two intersecting dichroic mirrors (Patent Document 1). .

Further, as a multicolor projection device, one that utilizes diffraction by a hologram is known (Patent Document 2).

JP 2019-174515 Publication Japanese Patent Application Publication No. 3-198491

However, if an attempt is made to miniaturize the device while using a dichroic prism as exemplified in Patent Document 1, the dichroic prism itself will inevitably be miniaturized. There is a concern that the effects of image quality deterioration in these areas will be greater. Note that Patent Document 2 above discloses an aspect that does not use a dichroic prism, but such a configuration does not require much effort, such as making it easily portable or being able to be incorporated into other equipment. It is not always possible to form high-definition images while downsizing the entire device. At least in Patent Document 2, there is no sufficient disclosure to enable miniaturization to such a size.

A projector according to one aspect of the present invention includes a plurality of display elements that emit light in different wavelength bands, a plurality of diffraction elements that diffract each color light emitted from the plurality of display elements, and a plurality of color lights emitted from the plurality of diffraction elements. and a projection optical system that projects the composite light generated by the composite diffraction element.

FIG. 2 is a conceptual side sectional view for explaining the projector of the first embodiment. FIG. 2 is a conceptual plan view showing how a projector projects images onto a screen. FIG. 2 is a conceptual perspective view showing an example of the external appearance of a projector. FIG. 3 is a conceptual front view showing an example of an arrangement of display elements. FIG. 7 is a conceptual side sectional view showing a modified example of a composite diffraction element. FIG. 7 is a conceptual side sectional view for explaining a projector according to a second embodiment. FIG. 2 is a conceptual plan view showing how a projector projects images onto a screen. It is a conceptual side sectional view for explaining the projector of a modified example. FIG. 2 is a conceptual side sectional view showing an example of the external shape of the projector. FIG. 2 is a conceptual diagram showing an example of application of a projector. FIG. 7 is a conceptual side sectional view for explaining another modified example of the projector.

[First embodiment]
DESCRIPTION OF THE PREFERRED EMBODIMENTS A projector according to a first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a conceptual side sectional view for explaining a projector 100 of this embodiment. Further, FIG. 2 is a conceptual side sectional view showing how the projector 100 projects onto the screen SC. As shown in FIG. 1, the projector 100 includes a light source section 10, a light guide device 20, and a projection optical system 30. Note that each of these parts is housed in the housing CS along with various circuits, power supplies, etc., which are not shown.

Note that in FIG. 1 and the like, X, Y, and Z are an orthogonal coordinate system, and the +Z direction indicates the emission direction of the image light GL in the light source section 10 and indicates the optical axis direction. Further, the X direction corresponds to the lateral direction (horizontal direction) of the light source section 10, and the Y direction corresponds to the vertical direction (vertical direction) perpendicular to the lateral direction (horizontal direction).

The light source section 10 includes three (plural) display elements 11r, 11g, and 11b that emit light in different wavelength bands, and a support substrate BS that supports them. Each display element 11r, 11g, 11b is represented by, for example, an organic EL (organic electro-luminescence), an inorganic EL, an LED array (micro LED array), an organic LED, a laser array, a quantum dot light-emitting element, etc. It is a self-luminous display device that forms still images or moving images of each color on a two-dimensional display section parallel to the XY plane.

Among the plurality of display elements 11r, 11g, and 11b, the display element 11r, which is the first display element, emits light in the red wavelength band as light in the first wavelength band. The display element 11g, which is the second display element, emits light in the green wavelength band as light in the second wavelength band. The display element 11b, which is the third display element, emits light in the blue wavelength band as light in the third wavelength band. The support substrate BS is a single plate-like member, and its surface is parallel to the XY plane. The support substrate BS is a panel substrate that supports each of the display elements 11r, 11g, and 11b and is provided with a drive circuit for driving them.

In the illustrated example, the three display elements 11r, 11g, and 11b are arranged on the surface of the support substrate BS, with the display element 11b, which is the third display element emitting light in the blue wavelength band, that is, the light in the shortest wavelength band, being the center. That is, they are arranged in a line in the vertical direction (Y direction) in one plane (XY plane).

The light guide device 20 includes a first light guide member 21 and a second light guide member 22. The first light guide member 21 includes a first diffraction element DE1, a first glass substrate GS1 that is a plate-like member and is transparent, and a plurality of collimating lenses COr, COg, and COb. Among these, the first diffraction element DE1 is composed of three (plural) diffraction elements 21r, 21g, and 21b, and is attached and fixed to the first glass substrate GS1. Each diffraction element 21r, 21g, 21b is provided so as to face the display element 11r, 11g, 11b, respectively, and is a transmissive type that diffracts each color light emitted from the display element 11r, 11g, 11b. It is a hologram element. Here, it is considered that a volume hologram is employed as the transmission type hologram element, but it is also possible to use other hologram elements.

Here, each of the collimating lenses COr, COg, and COb is a collimator that collimates the light beams of each color light passing through, and is located between the display elements 11r, 11g, and 11b and the diffraction elements 21r, 21g, and 21b, i.e. It is provided at the front stage (−Z side) of the diffraction elements 21r, 21g, and 21b. Thereby, each color light from the display elements 11r, 11g, and 11b enters the diffraction elements 21r, 21g, and 21b in a collimated state.

The second light guide member 22 includes a second diffraction element DE2 and a second glass substrate GS2 that is a single plate-like member and is light-transmissive. The second diffraction element DE2 is a synthetic diffraction element that synthesizes the light from the first diffraction element DE1, that is, each color light from the three display elements 11r, 11g, and 11b, and is attached and fixed to the second glass substrate GS2. . Further, the second diffraction element DE2 is a transmission type hologram element, and emits the combined light toward the projection optical system 30 while diffracting it. Here, it is considered that a volume hologram is employed as the transmission type hologram element, but it is also possible to use other hologram elements.

The projection optical system 30 projects the composite light generated by the second diffraction element DE2, which is a composite diffraction element, as image light GL. That is, as illustrated in FIG. 2, the image light GL that has passed through the projection optical system 30 is emitted toward the screen SC to form an image.

Hereinafter, the generation and projection of the image light GL with the above configuration will be explained along the optical path of each color light. Here, regarding the three display elements 11r, 11g, and 11b that generate respective component lights constituting the image light GL, the light emitted from the display element 11r is defined as red light GLr, and the light emitted from the display element 11g is defined as green light. The light GLg is assumed to be light, and the light emitted from the display element 11b is assumed to be blue light GLb.

First, the red light GLr emitted from the display element 11r is collimated by the collimating lens COr of the first light guide member 21 and enters the diffraction element 21r. When the red light GLr whose traveling direction is in the +Z direction is incident on the diffraction element 21r, it is deflected as a whole to include the -Y direction slightly due to diffraction at the diffraction element 21r, and the red light GLr travels in the second light guide member 22. It heads toward the diffraction element DE2.

Next, the green light GLg emitted from the display element 11g is collimated by the collimating lens COg and enters the diffraction element 21g. When the green light GLg whose traveling direction is in the +Z direction is incident on the diffraction element 21g, it is deflected as a whole to slightly include the +Y direction by diffraction at the diffraction element 21g, and heads toward the second diffraction element DE2.

Finally, the blue light GLb emitted from the display element 11b is collimated by the collimating lens COb and enters the diffraction element 21b. When the blue light GLb whose traveling direction is in the +Z direction is incident on the diffraction element 21b, it is deflected by diffraction at the diffraction element 21b so as to be concentrated closer to the center, and then heads toward the second diffraction element DE2.

As described above, each color light GLr, GLg, and GLb is deflected so as to be concentrated on one second diffraction element DE2 during diffraction at the first diffraction element DE1.

The second diffraction element DE2 exhibits different diffraction effects depending on the wavelengths and angles of incidence of the incident color lights GLr, GLg, and GLb, and synthesizes the respective color lights GLr, GLg, and GLb into image light. Form GL. That is, color synthesis is performed corresponding to the viewing angles of the display elements 11r, 11g, and 11b. In other words, the second diffraction element DE2 performs different diffraction actions corresponding to the light in each wavelength band from the three display elements 11r, 11g, and 11b, and aligns the optical paths of the respective color lights GLr, GLg, and GLb. . Thereby, the second diffraction element DE2 functions as a composite diffraction element that combines the respective color lights GLr, GLg, and GLb.

The image light GL formed by color synthesis in the second diffraction element DE2 is projected by the projection optical system 30 toward the screen SC (see FIG. 2). That is, the image light GL forms an image on the screen SC. As described above, a color still image or moving image is formed on the screen SC.

Note that the second diffraction element DE2 has a one-layer structure using a transmission hologram created by simultaneous exposure to three color lights, for example, red light (R light), green light (G light), and blue light (B light). However, it is also possible to have a multilayer structure. The second diffraction element DE2 is a synthetic diffraction element that performs light synthesis by diffraction effect for each color light, and it is also possible to have a multilayer structure in which diffraction elements corresponding to each color light are stacked. Note that an example of the multilayer structure will be described in detail later with reference to FIG. 5.

As described above, in the projector 100, by arranging the first diffraction element DE1 and the second diffraction element DE2, it is possible to synthesize each color light using the diffraction effect. This eliminates the need to consider the effects of image quality deterioration due to miniaturization, as is the case with dichroic mirrors formed by crossing dichroic mirrors, and allows the overall device to be miniaturized while maintaining high image quality. It is also possible to form high-brightness images while saving power. Furthermore, the light source unit 10 is a self-luminous display device that can be configured to emit high-intensity light, and in this case, a separate light source or a large power supply unit that supplies power to the light source is not required, and the entire projector 100 in size and weight. In addition, in the above, since the components of the corresponding angle of view of each color light GLr, GLg, and GLb are ultimately imaged at the same point on the screen SC (see FIG. 2), the components of the second diffraction element DE2 and It can also be considered that the projection optical system 30 is working together to synthesize light.

Further, in this case, by using the first diffraction element DE1 and the second diffraction element DE2, which are plate-shaped and transmissive, the projector 100 can be made linear and extremely compact. Therefore, for example, as shown in state AR1 and state AR2 in FIG. 3, the projector 100 can be shaped like a pen, and the image light GL can be emitted from a portion corresponding to the pen tip. . Note that in the example shown in state AR1, the casing CS that defines the external appearance of the projector 100 has a cylindrical shape, and in the example shown in state AR2, the casing CS that defines the external appearance of the projector 100 has a prismatic shape.

An example of the arrangement of the three display elements 11r, 11g, and 11b that constitute the light source section 10 will be described below with reference to FIG. 4. In FIG. 4, state BR1 is a front view showing the example arrangement described above. As shown in the figure, the three display elements 11r, 11g, and 11b are rectangular panel-type elements that are horizontally long (longer in the Y direction than in the X direction), and in one plane (XY plane). (Y direction). In this case, when viewed from the front, the light source section 10 can have an overall vertically elongated configuration with less spread in the X direction (horizontal direction). However, the arrangement is not limited to this arrangement; for example, the three display elements 11r, 11g, and 11b may be arranged in a triangular shape in one plane (XY plane), as shown in state BR2 or BR3. It's okay. That is, one of the three display elements 11r, 11g, and 11b is placed on the top side (+Y side), and the other two are placed on the bottom side (-Y side), or the other two are placed on the bottom side (-Y side). It is also conceivable to have the arrangement upside down. In this case, as shown in state BR2, when viewed from the front, the light source section 10 can have an overall horizontally elongated configuration with increased spread in the X direction (lateral direction). Alternatively, as shown in state BR3, when viewed from the front, the light source section 10 can have an overall circular shape or a shape close to this (a shape that spreads isotropically from the center).

In addition, in the case of a triangular arrangement as shown in state BR2 etc., the arrangement of the diffraction elements 21r, 21g, 21b corresponding to the three display elements 11r, 11g, 11b is also shown in front view as shown by broken lines in the figure. The second diffraction element DE2 is arranged in a triangular shape, and the second diffraction element DE2 is arranged at the center or near the center when viewed from the front, as shown by the dashed line in the figure.

In the above, considering the degree of diffraction, the arrangement is such that the blue light GLb, which is the light in the shortest wavelength band, is emitted from the center side where it is thought that there is the least bending due to diffraction, but the arrangement relationship is The present invention is not limited to this, and various embodiments are possible.

Hereinafter, referring to FIG. 5, it is a conceptual side sectional view showing a modified example of the second diffraction element DE2, which is a composite diffraction element.

Here, as described above, an example will be shown in which the second diffraction element DE2 has a multilayer structure. In the example shown in state CR1 in FIG. 5, the second diffraction element DE2 has a three-layer structure ( It consists of 3 sheets). That is, the blue diffraction element 22b exhibits a diffraction effect on the blue light (B light) GLb component among the three color lights having a predetermined wavelength band that constitute the image light GL from the light source section 10, while diffraction action is performed on the component of the blue light (B light) GLb. It has no effect on light and allows it to pass through. Similarly, the red diffraction element 22r exhibits a diffraction effect only on the component of red light (R light) GLr, and the green diffraction element 22g exhibits a diffraction effect only on the component of green light (G light) GLg. It has become. With such a configuration, the utilization efficiency of each color light can be further improved.

In the example shown in state CR1, the blue diffraction element 22b, red diffraction element 22r, and green diffraction element 22g corresponding to each wavelength have a thickness of about 20 to 40 μm, and are made of light-transmitting resin. Alternatively, it is configured by being attached to a glass substrate BSb, BSr, or BSg. Note that the thickness of the substrates BSb, BSr, and BSg may be approximately 0.3 mm, but may be made thinner. The diffraction elements 21b, 21r, and 21g attached to the substrates BSb, BSr, and BSg are fixed with intervals (gap) DD1 and DD2 of about 50 μm. The distances DD1 and DD2 are ensured by attaching spacers SS to peripheral portions of the diffraction elements 21b, 21r, and 21g that do not exhibit optical effects. By providing such intervals DD1 and DD2, an air layer AL is formed between the layers of the three-layer structure, and it is possible to avoid unintended total reflection on the substrate BSb and the like. Further, by having the thickness as described above, even if the second diffraction element DE2 has a three-layer structure, the device as a whole can maintain a certain degree of thinness in the Z direction. Further, in this case, the second glass substrate GS2 may be omitted if it has sufficient strength.

On the other hand, if there is no risk of unintentional total reflection as described above due to the angle of incidence, etc., the example shown in state CR2 may be used without providing the spacer SS or the resulting intervals DD1 and DD2. With such a configuration, the second diffraction element DE2 having a three-layer structure may be further miniaturized.

In the illustrated second diffraction element DE2, the diffraction elements for blue, red, and green are arranged in order from the light incident side, but the order of arrangement is not limited to this, and may be arranged in various ways. be able to.

As described above, the projector 100 of the present embodiment includes a plurality of display elements 11r, 11g, and 11b that emit light in different wavelength bands, and each color light GLr and GLg emitted from the plurality of display elements 11r, 11g, and 11b. , GLb (first diffraction element DE1), and a first diffraction element which is a synthetic diffraction element which synthesizes each color light GLr, GLg, GLb from the plurality of diffraction elements 21r, 21g, 21b. It includes a second diffraction element DE2 and a projection optical system 30 that projects image light GL as a composite light generated by the second diffraction element DE2. In the projector 100, the second diffraction element DE2 combines the color lights GLr, GLg, and GLb that have passed through the diffraction elements 21r, 21g, and 21b, thereby improving the image quality at the center of the image compared to, for example, a case where a cross prism is used. The entire device can be made smaller while maintaining a high level of brightness, and high-brightness images can be formed while saving power.

[Second embodiment]
The projector according to the second embodiment will be described below with reference to FIG. 6 and the like. FIG. 6 is a conceptual side sectional view for explaining an example of the projector 100 of this embodiment, and corresponds to the side sectional view shown in FIG. As shown in the figure, this embodiment differs from the first embodiment in that reflective hologram elements are used as the first diffraction element DE1 and the second diffraction element DE2.

In this embodiment, the light guide device 20 includes a first diffraction element DE1 composed of a plurality of reflective diffraction elements 21r, 21g, and 21b as the first light guide member 21, and a first diffraction element DE1 as the second light guide member 22. , a reflective second diffraction element DE2. That is, in the light guide device 20, the first diffraction element DE1 and the second diffraction element DE2 are reflective hologram elements, and the first diffraction element DE1 and the second diffraction element DE2 face each other as shown in the figure. It is arranged as follows. Here, a volume hologram may be used as the reflective hologram element, but other hologram elements may also be used.

The first diffraction element DE1 as the first light guide member 21 diffracts the image light GL from the light source section 10 so as to reflect it. To explain more specifically along the optical path of each color light GLr, GLg, and GLb, first, in the light source section 10, the red light GLr emitted from the display element 11r enters the diffraction element 21r. is deflected by the diffraction of the light beam, and is directed toward the second diffraction element DE2 as the second light guide member 22. Similarly, when the green light GLg emitted from the display element 11g enters the diffraction element 21g, it is deflected by diffraction at the diffraction element 21g and heads toward the second diffraction element DE2, and the blue light emitted from the display element 11b When GLb enters the diffraction element 21b, it is deflected by diffraction at the diffraction element 21b and heads toward the second diffraction element DE2. However, in the illustrated example, the three display elements 11r, 11g, and 11b are arranged in a line in this order from the -Y side, and in order to combine them in the second diffraction element DE2, the optical path is bent by each diffraction action. The degree is different.

In the illustrated example, considering the degree of diffraction, the arrangement is such that light with longer wavelength bands is emitted from the -Y side, where the bending due to diffraction is greatest, but the arrangement is limited to this. However, various embodiments are possible.

The respective color lights GLr, GLg, and GLb collected in the second diffraction element DE2 as described above are combined in the second diffraction element DE2. At this time, the second diffraction element DE2 as a composite diffraction element also performs angle compensation for the diffraction angles in each of the diffraction elements 21r, 21g, and 21b. That is, when the color lights GLr, GLg, and GLb are emitted from the second diffraction element DE2, they are emitted at the same angle as the incident angle to the diffraction elements 21r, 21g, and 21b. For example, the image light GL, which is a composite light obtained by combining the color lights GLr, GLg, and GLb that have entered the diffraction elements 21r, 21g, and 21b from the +Z direction, is emitted toward the +Z direction. The image light GL that has passed through the second diffraction element DE2 is projected by the projection optical system 30 toward the screen SC (see FIG. 7).

In the above example, an air layer is formed between the light source section 10, the first diffraction element DE1, and the second diffraction element DE2.

Here, regarding the first diffraction element DE1 (diffraction elements 21r, 21g, 21b) and the second diffraction element DE2, for example, the first glass substrate GS1 and the second glass substrate GS2 (Fig. 1) etc., and the three display elements 11r, 11g, 11b constituting the light source section 10 may be supported by a support substrate BS. For example, as shown in FIG. In place of the air layer, a light transmitting member 23 which is a plate-shaped transparent member is provided, and the light source section 10 (display elements 11r, 11g, 11b), the first diffraction element DE1 and A configuration may be adopted in which the second diffraction element DE2 is attached and each color light GLr, GLg, and GLb to become the image light GL is guided inside the light transmitting member 23.

In this embodiment, by using reflective hologram elements as the first diffraction element DE1 and the second diffraction element DE2, the device can be made thinner. For example, when it is housed in a casing as illustrated in FIG. 9, it is possible to make the parts other than the projection optical system (projection lens) 30 thinner. As a result, for example, as shown in state DR1 in FIG. 10, the projector 100 is incorporated into a thin portable device MD such as a smartphone equipped with various devices such as a camera CA to project an image. becomes possible. Furthermore, as illustrated in state DR2 in FIG. 10, the projector 100 can be easily installed in the glasses GA worn by the observer or wearer US, and the real space beyond the line of sight of the observer or wearer US It becomes possible to perform image projection on the image. Furthermore, by adding a switching mechanism CH that can project an image from the projector 100 onto the glasses lens LG of the glasses GA, the glasses GA can be configured as a head-mounted display. Further, as illustrated in state DR3 in FIG. 10, the degree of freedom in installing the projector 100 is increased for the viewer M, and installation becomes easier. The projector 100 can be easily installed on the seating area CM or ceiling CL of the viewer M, and the viewer M can view the image using the wall surface of the wall WA as the screen SC. Note that the seating portion CM can also be used as a driver's seat of an automobile. It should be noted that each of the above-mentioned incorporation aspects may be employed not only in this embodiment but also in the first embodiment within the scope of applicability.

Further, as shown in FIG. 11, the light source section 10 projects component light EL having a transmission wavelength that passes through the first diffraction element DE1 as a component other than the image light GL toward the screen SC, and also projects the component light EL as a component other than the image light GL. Of these, a configuration may also be considered in which a light receiving section RR that receives the return light RL from the screen SC is provided. To explain more specifically, in any one of the three diffraction elements 21r, 21g, and 21b (in the illustrated example, the diffraction element 21r) constituting the first diffraction element DE1, an image such as ultraviolet light or infrared light is generated. The design is such that it does not exhibit a diffraction effect on components other than light GL (components other than visible light in a specific wavelength band) and allows them to pass through. In this case, for example, as the component light EL, the light in the wavelength band of infrared light is emitted from the display element 11r of the light source section 10, while the component in the wavelength band included in the component light EL can be detected. It is conceivable that the light receiving section RR is constituted by a photodetector or the like and is separately arranged so that the light receiving surface of the light receiving section RR is aligned with the light emitting surface of the display element 11r. Note that for the component light EL emitted from the light source section 10, for example, in the display element 11r, an infrared light array or the like may be arranged in the panel.

In this case, by emitting component light EL (infrared light) toward the front (+Z direction) of the projector 100 as sensing light, it is possible to detect the position of the screen SC and further to sense the shape of the projection surface. can. In the illustrated example, an optical element OL for condensing the returned light RL is provided, but various types of optical elements such as a diffraction element in addition to a lens can be employed as the optical element OL.

In this embodiment as well, the second diffraction element DE2 synthesizes the respective color lights GLr, GLg, and GLb that have passed through the diffraction elements 21r, 21g, and 21b, thereby reducing the size of the entire apparatus while maintaining high image quality. It is also possible to form high-brightness images while saving power. In particular, this embodiment allows the entire device to be made thinner. For example, this is particularly effective for a mobile device MD equipped with the projector 100 of this embodiment illustrated in state CR1 in FIG. 10, and it is possible to improve the quality of images projected by the mobile device MD.

[Other variations]
Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments, and can be implemented in various forms without departing from the gist thereof. Modifications such as the following are also possible.

In the projector 100 of each of the embodiments described above, a self-luminous light source unit 10 that includes an organic EL element, a micro LED array, etc. is used, but instead of this, a device that uses a laser light source etc. is also applicable. It is also possible to do so.

Further, when the light source section 10 is configured with an organic EL element, a micro LED array, etc., the direction of the emitted image light GL may be adjusted using a micro lens array or the like. Further, if sufficient collimation is thereby possible, a configuration may be considered in which the collimating lenses COr, COg, and COb are not provided in FIG.

In addition, if there is a possibility that color separation may occur during diffraction at the first diffraction element DE1 because the light source has a predetermined wavelength bandwidth for each colored light, the second diffraction element DE2 may compensate for this. It may be configured as follows.

Furthermore, it is also possible to employ the projector 100 of each of the embodiments described above to constitute a head-up display.

In a specific embodiment, the projector includes a plurality of display elements that emit light in different wavelength bands, a plurality of diffraction elements that diffract each color light emitted from the plurality of display elements, and a plurality of diffraction elements that diffract each color light emitted from the plurality of display elements. It includes a combining diffraction element for combining, and a projection optical system for projecting the combined light generated by the combining diffraction element.

In the above projector, by using a composite diffraction element to combine each color light that has passed through multiple diffraction elements, the overall device can be made smaller while maintaining a high image quality in the center of the image compared to, for example, a case where a cross prism is used. In addition, it is possible to form high-brightness images while saving power.

In a specific aspect, the plurality of display elements includes a first display element that emits light in a first wavelength band, a second display element that emits light in a second wavelength band, and a third display element that emits light in a third wavelength band. The composite diffraction element performs different diffraction actions corresponding to the light in each wavelength band from the plurality of display elements, and aligns the optical paths of the respective color lights. In this case, each color of light emitted from the three display elements as a plurality of display elements can be synthesized by diffraction.

In a specific aspect, the plurality of display elements are three panel type elements, and are arranged in one direction in one plane. In this case, the planar range in which the display elements are arranged can have an elongated configuration with less spread in a direction different from one direction.

In a specific aspect, the plurality of display elements are three panel type elements and are arranged in a triangular shape within one plane. In this case, the planar range in which the display elements are arranged can be configured to have an isotropic spread.

In a specific aspect, the plurality of diffraction elements and the composite diffraction element are transmission holograms. In this case, it is possible to reduce the size of the apparatus without causing deterioration in image quality, which would occur if, for example, a dichroic prism is also used.

In a specific aspect, a plurality of collimating lenses are provided between the plurality of display elements and the plurality of diffraction elements to collimate the light passing therethrough. In this case, the desired diffraction effect can be reliably produced.

In a specific aspect, the plurality of diffraction elements and the composite diffraction element are reflective holograms. In this case, the device can be made thinner without deteriorating the image quality as would be the case if, for example, a dichroic prism is also used.

In a specific aspect, the combining diffraction element combines colored lights while performing angular compensation for diffraction angles in a plurality of diffraction elements.

In a specific aspect, the composite diffraction element has a single layer structure. In this case, it is possible to have a simple configuration and downsize the device.

In a specific aspect, the composite diffraction element has a multilayer structure. In this case, for example, by performing appropriate diffraction for each color light, it becomes possible to use light with high efficiency.

In a specific aspect, in the multilayer structure, an air layer is provided between each layer. In this case, the occurrence of unintended total reflection inside the composite diffraction element can be avoided or suppressed.

In a specific aspect, the plurality of diffraction elements and the composite diffraction element are configured by volume holograms. In this case, the intended diffraction effect can be accurately produced.

In a specific aspect, the display element includes either an organic EL element or a micro LED array. In this case, a stable amount of light can be ensured with a simple configuration while reducing power consumption.

DESCRIPTION OF SYMBOLS 10... Light source part, 11b, 11g, 11r... Display element, 20... Light guide device, 21... First light guide member, 21b, 21r, 21g... Diffraction element, 22... Second light guide member, 22b... Diffraction for blue color Element, 22g... Diffraction element for green color, 22r... Diffraction element for red color, 23... Light transmission member, 30... Projection optical system, 100... Projector, AL... Air layer, BS... Support substrate, BSb, BSr, BSg... Substrate, CA...Camera, CH...Switching mechanism, CL...Ceiling, CM...Seating section, COb, COg, COr...Collimating lens, CS...Housing, DD1, DD2...Interval, DE1...First diffraction element, DE2...Second Diffraction element, EL... component light, GA... glasses, GL... image light, GLb... blue light, GLg... green light, GLr... red light, GS1... first glass substrate, GS2... second glass substrate, LG... glasses lens , M...Viewer, MD...Mobile device, OL...Optical element, RL...Return light, RR...Light receiving section, SC...Screen, SS...Spacer, WA...Wall

Claims (13)

a plurality of display elements that emit light in different wavelength bands;
a plurality of diffraction elements that diffract each color light emitted from the plurality of display elements;
a synthesizing diffraction element that synthesizes the respective color lights from the plurality of diffraction elements;
A projector comprising a projection optical system that projects composite light generated by the composite diffraction element. The plurality of display elements includes a first display element that emits light in a first wavelength band, a second display element that emits light in a second wavelength band, and a third display element that emits light in a third wavelength band. is,
2. The projector according to claim 1, wherein the composite diffraction element performs different diffraction actions corresponding to the light in each wavelength band from the plurality of display elements to align the optical paths of the respective color lights. 3. The projector according to claim 2, wherein the plurality of display elements are three panel type elements arranged in one direction in one plane. 3. The projector according to claim 2, wherein the plurality of display elements are three panel type elements arranged in a triangular shape within one plane. The projector according to claim 1, wherein the plurality of diffraction elements and the composite diffraction element are transmission holograms. The projector according to claim 5, further comprising a plurality of collimating lenses that are provided between the plurality of display elements and the plurality of diffraction elements and collimate the light that passes therethrough. The projector according to claim 1, wherein the plurality of diffraction elements and the composite diffraction element are reflection holograms. 8. The projector according to claim 7, wherein the combining diffraction element combines the colored lights while performing angular compensation for diffraction angles in the plurality of diffraction elements. The projector according to any one of claims 1 to 8, wherein the composite diffraction element has a one-layer structure. The projector according to any one of claims 1 to 8, wherein the composite diffraction element has a multilayer structure. The projector according to claim 9, wherein in the multilayer structure, an air layer is provided between each layer. The projector according to any one of claims 1 to 11, wherein the plurality of diffraction elements and the composite diffraction element are configured by volume holograms. 13. The projector according to claim 1, wherein the display element includes one of an organic EL element and a micro LED array.

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