JP2000029135A - Video projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video projection device by which the video light beams of red, green and blue are synthesized without using a dichroic prism. SOLUTION: A pyramid body mirror 1 is formed into a triangular pyramid shape provided with a first reflection surface 1a reflecting a blue light video emitted from a first video display panel 11 in the upper direction of the figure, a second reflection surface 1b reflecting a green light video emitted from a second video display panel 12 similarly in the upper direction and a third reflection surface 1c reflecting a red light video emitted from a third video display panel 13 similarly in the upper direction. The video light beams of the respective colors of the video display panels 11, 12 and 13 are synthesized by the pyramid body mirror 1 and a color video light beam obtained by synthesis is led to a projection lens 2 arranged on the upper side of the pyramid body mirror 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video projection device used for a rear projection type or front projection type video display device.

[0002]

2. Description of the Related Art FIG. 8 is a plan view showing a three-plate (R, G, B) type image projection device 60 in a projection type image display device. Light emitted from a lamp (halogen lamp or metal halide lamp) 62 a is reflected by a condenser reflector 61, ultraviolet and infrared rays are removed by a UV / IR filter 63, emitted from a light source device 62, and incident on a dichroic mirror 51. I do. The dichroic mirror 51 transmits red light (R) and reflects green light (G) and blue light (B). The red light separated by the dichroic mirror 51 is reflected by a total reflection mirror 52 and provided to a red liquid crystal panel 53 that displays a red image. The red light passes through the liquid crystal panel 53 with its transmittance changed, and is then given to a dichroic prism 54 as a light combining means.

On the other hand, the green light and the blue light reflected by the dichroic mirror 51 are given to a dichroic mirror 55. This dichroic mirror 55 is green (G)
And reflects the blue light (B). The green light separated by the dichroic mirror 55 is provided to a green liquid crystal panel 56 that displays a green image. The green light passes through the liquid crystal panel 56 with its transmittance changed, and is then given to the dichroic prism 54.

[0004] The blue light transmitted through the dichroic mirror 55 is reflected by total reflection mirrors 57 and 58 and is applied to a blue liquid crystal panel 59 for displaying a blue image.
The blue light passes through the liquid crystal panel 59 after changing its transmittance, and is then provided to the dichroic prism 54.

[0005] The image lights of the respective colors that have entered the dichroic prism 54 are combined and emitted as color image light. Then, the projected color image light is transmitted to the projection lens 6.
4 and projected on a screen (not shown).

[0006]

Since the dichroic prism 54 is obtained by polishing four right-angle prisms and depositing a thin film on the polished surface and bonding them, the manufacturing cost is high. Therefore, the conventional video projector using the dichroic prism 54 has a disadvantage that it is expensive.

An object of the present invention is to provide an image projection apparatus that combines image lights of R, G, and B colors without using a dichroic prism in view of the above circumstances.

[0008]

In order to solve the above-mentioned problems, an image projection apparatus according to the present invention comprises: a first reflection surface for reflecting a blue light image emitted from a first image display panel in a predetermined direction; A second reflecting surface for reflecting the green light image emitted from the second image display panel in the substantially same direction as the predetermined direction; and a red light image emitted from the third image display panel in the substantially same direction as the predetermined direction. A pyramidal mirror having at least a third reflecting surface that reflects light is arranged, and the pyramidal mirror is used to combine image light of each color.

With the above arrangement, the image light of each color is synthesized by the pyramid mirror. Since the pyramid mirror is easier to manufacture than the dichroic prism and can reduce the manufacturing cost, the price of the image projection device can be reduced.

A specific example of the video compositing requirements in the above-described video projection device is as follows. That is, a first reflecting surface for reflecting a blue light image emitted from the first image display panel in a predetermined direction, and a second reflecting surface for reflecting a green light image emitted from the second image display panel in the same direction as the predetermined direction. A pyramid mirror having at least a third reflecting surface for reflecting a red light image emitted from the reflecting surface and the third image display panel in substantially the same direction as the predetermined direction, and combining each color image light by the pyramid mirror. A projection lens for projecting color image light, wherein the optical axis of the projection lens intersects the apex of the pyramidal mirror, and the perpendicular to the display surface starting from the center of the display area in the video display panel is the pyramid. The vertical line and the optical axis of the projection lens intersect with the vertex of the body mirror, and coincide with the input / output optical path in the light incident / reflected relationship via the reflecting surface of the pyramidal mirror.

The image projection apparatus according to the present invention further comprises a first reflecting surface for reflecting a blue light image emitted from the first image display panel in a predetermined direction, and a green light image emitted from the second image display panel. A second reflecting in substantially the same direction as the predetermined direction;
A micro pyramid in which a plurality of micro pyramid mirrors each having at least a reflecting surface and a third reflecting surface for reflecting a red light image emitted from the third image display panel in a direction substantially the same as the predetermined direction are arranged. A body mirror plate is arranged, and the video light of each color is synthesized by the minute pyramid mirror plate.

With the above arrangement, the image light of each color is synthesized by the minute pyramid mirror plate. This micro pyramid mirror plate can be manufactured, for example, by performing anisotropic etching or the like on a Si base, and can be manufactured more easily and at a lower manufacturing cost than a dichroic prism, so that the price of an image projection device can be reduced. it can. In this configuration, the first image display panel, the second image display panel, and the third image display panel each include a minute lens for each pixel, and each minute lens has a corresponding minute pyramid mirror. It is desirable that the lens is formed so as to have a focal length corresponding to the distance to the camera.

[0013]

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1A is a perspective view showing an arrangement relationship of main elements in the image projection apparatus according to this embodiment.
FIG. 2B is a plan view showing an arrangement relationship of the main elements, FIGS. 2A and 2B are side views showing an arrangement relation of the main elements, and FIG. 3 is a pyramid. It is explanatory drawing at the time of adopting a quadrangular pyramid as a mirror. Note that a configuration (color separation optical system) for dispersing white light emitted from a lamp (not shown) (halogen lamp or metal halide lamp) into red light, green light, and blue light and leading the liquid crystal display panel for each color to: This can be realized by applying a configuration substantially similar to the configuration of FIG. 8 described in the item of the conventional example.

The bottom surface of the pyramid mirror 1 forms an equilateral triangle, and the three side surfaces form an isosceles triangle having the same shape.
The angle formed between the bottom surface and the side surface is 45 °. The three side surfaces are mirror-processed to form a first reflecting surface 1a, a second reflecting surface 1b, and a third reflecting surface 1c. The pyramid mirror 1 is easier to manufacture than the dichroic prism, and the manufacturing cost can be reduced.

The first image display panel 11 and the second image display panel 11 are arranged so as to face the three reflecting surfaces 1a, 1b and 1c, respectively.
An image display panel 12 and a third image display panel 13 are arranged. The image display surface of the first image display panel 11 is parallel to the bottom of the first reflection surface 1a and perpendicular to the bottom of the pyramid mirror 1. The image display surface of the second image display panel 12 is parallel to the bottom of the second reflection surface 1b and perpendicular to the bottom of the pyramid mirror 1. The image display surface of the second image display panel 12 is parallel to the bottom of the third reflection surface 1c and perpendicular to the bottom of the pyramid mirror 1. Then, the first reflection surface 1a reflects the blue light image emitted from the first image display panel 11 in the upward direction in the figure, and the second reflection surface 1b is emitted from the second image display panel 12. The green light image is also reflected upward, and the third reflection surface 1c
Are configured to reflect the red light image emitted from the third image display panel 13 upward similarly.

The optical axis of the projection lens 2 (indicated by a dashed line in FIG. 2A) and the image display panels 11, 1
2 and 13 (indicated by a dashed line in FIG. 2A), the respective images after reflection by the pyramidal mirror 1 have their centers coincident with each other and the projection lens 2 The light is guided to the projection lens 2 in accordance with the optical axis. In other words, the optical axis of the projection lens 2 intersects the apex of the pyramid mirror 1, and the perpendicular (image center line) to the display surface starting from the center of the display area in the image display panels 11, 12, 13 is The vertical line and the optical axis of the projection lens 2 intersect with the apex of the pyramid mirror 1, and coincide with the incident / emission optical path in the light incident / reflection relation via the reflection surface of the pyramid mirror 1.

Each of the image display panels 11, 12, and 13 is composed of, for example, a liquid crystal panel, and displays a blue image, a green image, and a red image in a color image, respectively, but their arrangements (display directions) are not the same. For example, "A"
Is displayed on the first video display panel 11 as shown in the figure, the second video display panel 12 is arranged such that "A" is displayed in a substantially right and left opposite direction, and the third video display panel 13 Are arranged such that “A” is displayed substantially upside down. Then, by the above pyramid mirror 1,
The color image lights of the image display panels 11, 12, and 13 are combined, and the color image light obtained by the combination is guided to the projection lens 2 disposed above the pyramid mirror 1. Note that the specific display direction of each panel can be easily known by arranging a character having the letter “A” above the apex of the pyramidal mirror 1 and viewing the image reflected on each reflecting surface. it can.

When a video projection device having such a structure is provided in a rear projection type video display device, for example, a reflection mirror (not shown) is arranged on the projection light direction of the projection lens 2 and reflected by this reflection mirror. The image light is projected on the back side of the diffusion screen (not shown).

The pyramid mirror is not limited to a triangular pyramid, but may be a quadrangular pyramid (side surface isosceles triangle). In this case, as shown in FIG. 3, the four reflecting surfaces 15a, 1
Three surfaces among 5b, 15c and 15d will be used. When the character "R" is to be formed as shown as a virtual image in the figure, the video display panels 11, 12, and 13 are arranged as shown in the figure.

In the above-described embodiment, the angle formed between the bottom surface and the side surface of the pyramid mirror 1 is 45 °. However, the present invention is not limited to this. For example, a virtual line shown in FIG. The angle may be smaller than 45 ° as shown, and the display panel may be arranged as shown by a virtual line. That is, as described above, the optical axis of the projection lens 2 and
The image center lines of the respective image display panels coincide with each other, and the images reflected by the pyramid mirror 1 are guided to the projection lens 2 with their centers coincident with each other and with the optical axis of the projection lens 2. It should just be. Further, it is more preferable to irradiate each color light from diagonally above to each liquid crystal display panel so that all of the light transmitted through each video display panel easily hits the reflection surface of the pyramid mirror 1. In this case, In the color separation optical system, the optical path may be designed so that each color light is emitted to each liquid crystal display panel from obliquely above.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to FIGS.

FIG. 4 is a perspective view showing an arrangement relationship of main elements in the image projection apparatus according to this embodiment. In addition,
The configuration for dispersing the white light emitted from a lamp (not shown) into red light, green light, and blue light and guiding the same to the liquid crystal display panel for each color is substantially the same as the configuration of FIG. It can be realized by applying something.

A first video display panel 21, a second video display panel 22, and a third video display panel 23 are arranged so as to surround the micro pyramid mirror plate 20 from three directions.
The blue light image emitted from the first image display panel 21 is reflected upward by the small pyramid mirror plate 20, and the green light image emitted from the second image display panel 22 is similarly reflected upward by the small pyramid mirror plate 20. The red light image emitted from the third image display panel 23 is also reflected upward.
In this reflection, the image lights of the three colors are combined and guided to the projection lens 24.

FIG. 5 is an enlarged perspective view of the micro pyramid mirror plate 20. The minute pyramid mirror plate 20 includes a large number of minute quadrangular pyramid mirror portions 20a corresponding to the number of pixels and the arrangement of pixels of the image display panel. Since the number of images is three, that is, a blue image, a green image, and a red image, three of the four reflecting surfaces in the quadrangular pyramid mirror unit 20a are used. Minute pyramid mirror plate 20
Is obtained, for example, by using a single crystal silicon substrate sliced along the (100) plane and performing anisotropic etching on the substrate surface using an alkaline solution such as sodium hydroxide. Then, by forming a reflective film of aluminum or the like on the substrate surface by vapor deposition or the like, each quadrangular pyramid becomes the quadrangular pyramid mirror section 20a. The minute pyramid mirror plate 20 can be manufactured by a mold in addition to the above-described manufacturing method by etching. The micro-pyramid mirror plate 20 that can be manufactured in this way can be manufactured more easily than the dichroic prism, and the manufacturing cost can be reduced. Further, the convex portion is not limited to a pyramid, and the concave portion may be formed in a pyramid shape. Such a concave part formed in a pyramid shape is also included in the concept of the micro pyramid mirror. Further, the pyramid mirror is not limited to a quadrangular pyramid, but may be a triangular pyramid.

FIG. 6 shows that the image light of each color from the three image display panels 23 enters the three reflecting surfaces of one quadrangular pyramid mirror portion 20a from obliquely above, and is reflected upward, whereby the color is reflected. This shows how the light becomes image light.

FIG. 7 shows an image display panel 21 (22, 2).
3) is shown in an enlarged manner, and also shows how light emitted from one pixel is reflected by one quadrangular pyramid mirror unit 20a corresponding to the pixel. Video display panel 2
In 1 (22, 23), a micro lens 24 is formed corresponding to each pixel. And each micro lens 2
4 has a focal length corresponding to the distance to the reflection surface of the corresponding quadrangular pyramid mirror section 20a.

According to the above configuration, since the micro-pyramidal mirror plate 20 which can be easily manufactured and whose manufacturing cost can be reduced is used, the price of the image projection apparatus can be reduced. Further, since each image display panel is disposed obliquely above the micro pyramid mirror plate 20, the distance between each pixel of the image display panel and each corresponding quadrangular pyramid mirror portion 20a is different. Since each video display panel includes the micro lens 24 for each pixel, image blur due to the difference in the distance is prevented.

[0029]

As described above, according to the present invention, it is possible to combine the image lights of the respective colors of R, G and B without using a dichroic prism, so that the cost of the image projection apparatus can be reduced. .

[Brief description of the drawings]

FIG. 1 is a perspective view showing an arrangement relationship of main elements of a video projection device according to a first embodiment of the present invention.

FIG. 2A is an explanatory diagram showing a state in which image light from an image display panel is reflected by a pyramidal mirror and travels toward a projection lens in the configuration of FIG. 1, and FIG. It is explanatory drawing which showed the modification of arrangement | positioning of a pyramid mirror and a video display panel.

FIG. 3 is an explanatory diagram in the case where a quadrangular pyramid mirror is employed as a pyramid reflecting mirror;

FIG. 4 is a perspective view showing an arrangement relationship of main elements of a video projection device according to a second embodiment of the present invention.

FIG. 5 is an enlarged perspective view showing a micro pyramid mirror plate according to a second embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a state in which image light of each color is reflected by one quadrangular pyramid mirror portion of the micro pyramid mirror plate of FIG. 5 to become color image light.

FIG. 7 is a modified example of the second embodiment of the present invention, in which light emitted from a substantially central pixel of a video display panel including a microlens is substantially square quadrangular pyramid mirror corresponding to the pixel; FIG. 5 is an explanatory diagram showing a state of being reflected by a section.

FIG. 8 is a plan view of a conventional video projection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pyramidal mirror 1a Reflection surface 2 Projection lens 11 1st image display panel 12 2nd image display panel 13 3rd image display panel 20 Micro pyramid mirror plate 20a Square pyramid mirror part 21 1st image display panel 22 2nd image Display panel 23 Third image display panel 24 Micro lens

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H088 EA14 EA15 MA20 2H089 QA16 TA16 TA17 UA05 2H091 FA14X FA26X FA50X FD07 LA30 MA07

Claims (5)

[Claims] A first reflecting surface for reflecting a blue light image emitted from the first image display panel in a predetermined direction; and a green light image emitted from the second image display panel in substantially the same direction as the predetermined direction. A pyramid mirror including at least a second reflecting surface for reflecting the light and a third reflecting surface for reflecting the red light image emitted from the third image display panel in the same direction as the predetermined direction; An image projection device, wherein image light of each color is synthesized by a mirror. 2. A first reflecting surface for reflecting a blue light image emitted from a first image display panel in a predetermined direction, and a green light image emitted from a second image display panel in substantially the same direction as the predetermined direction. A pyramid mirror having at least a second reflecting surface and a third reflecting surface that reflects a red light image emitted from the third image display panel in substantially the same direction as the predetermined direction;
A projection lens for projecting color image light obtained by synthesizing each color image light by the pyramid mirror, wherein an optical axis of the projection lens intersects a vertex of the pyramid mirror, and a center of a display area in the image display panel. The perpendicular to the display surface starting from the intersection point intersects the apex of the pyramidal mirror, and the perpendicular and the optical axis of the projection lens coincide with the input / output optical path in the light incident / reflective relationship via the reflecting surface of the pyramidal mirror. An image projection device characterized by the following. 3. The image projection device according to claim 1, wherein each color light applied to each image display panel is emitted obliquely from above. 4. A first reflecting surface for reflecting a blue light image emitted from the first image display panel in a predetermined direction, and a green light image emitted from the second image display panel in substantially the same direction as the predetermined direction. A plurality of planar pyramid mirrors each having at least a second reflecting surface for reflecting and a third reflecting surface for reflecting a red light image emitted from the third image display panel in a direction substantially the same as the predetermined direction are arranged in a plane. An image projection device, wherein a micro pyramid mirror plate is arranged, and video light of each color is synthesized by the micro pyramid mirror plate. 5. The first video display panel, the second video display panel, and the third video display panel each include a micro lens for each pixel, and each micro lens has a micro pyramid mirror corresponding to the micro lens. The image projection device according to claim 4, wherein the image projection device is formed to have a focal length according to the distance.