JP3010806B2 - LCD projector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector for projecting an image using a liquid crystal panel.

[0002]

2. Description of the Related Art Conventionally, there has been known a liquid crystal projector device which projects an image using, for example, a transmission type liquid crystal panel as shown in FIG. In this liquid crystal projector, the light emitting unit 51 is driven by the power supply 59, and the light emitting unit 51 is driven.
The light generated by the light emission is incident on a dichroic prism 52 for color separation.

Here, since the light generated by the light emission of the light emitting section 51 diverges in almost all directions, only a small part of the light passes through the dichroic prism 52 and the liquid crystal 54, and the light that can be taken into the projection lens 56 is reduced. Would.

Therefore, a conventional liquid crystal projector is
The reflector 60, which is a so-called parabolic mirror having a parabolic reflection surface, has been used. The light emitting section 51 is provided so as to be located at the focal point of the paraboloid of the reflector 60, and the light emitting section 51 and the reflector 60 constitute a light source section. The diffused light from the light emitting unit 51 is reflected by the reflector 60 and is incident on the dichroic prism 52 for color separation as parallel light. Therefore, the amount of parallel light incident on the dichroic prism 52 for color separation can be increased. Thus, the conventional liquid crystal projector device has the screen 57
To improve the brightness of the video projected on the screen.

In order to increase the amount of parallel light incident on the dichroic prism 52 for color separation without using the reflector 60, the amount of light emitted by driving the light emitting section 51 with high power is increased. The light emitting unit 51 generates heat when emitting light. For this reason, driving the light emitting unit 51 with a large amount of power generates high heat, which adversely affects surrounding circuits and the like, which is not preferable.

[0006] Conventional liquid crystal projector devices include:
In order to prevent the adverse effect of the heat generated by the light emission of the light emitting unit 51, an infrared cut filter 50 for preventing the transmission of heat by radiation and a cooling device 58 such as a fan for air cooling are provided. The infrared component contained in the light is removed by the infrared cut filter 50, and the heat of the light emitting section 51 itself is radiated by the cooling device 58.

[0007] The dichroic prism 52 decomposes the parallel light incident from the light source unit into red (R), green (G), and blue (B) light. Of the light of each color decomposed by the dichroic prism 52,
The red light is incident on the liquid crystal panel for red 54R via the mirror 53a and the mirror 53b. The green light is directly incident on the green liquid crystal panel 54G, and the blue light is incident on the blue liquid crystal panel 54B via the mirrors 53c and 53d.

[0008] The liquid crystal panels 54R, 54G for each of the above colors,
54B is controlled to display an arbitrary image by an image display circuit (not shown). For this reason, the light of each color corresponding to the above-mentioned arbitrary image is transmitted through the liquid crystal panels 54R, 54G, and 54B for each of the colors. The transmitted light of each color is incident on a dichroic prism 55 for color synthesis. The color synthesizing dichroic prism 55 includes a liquid crystal panel 54R for each color.
The transmitted lights of the respective colors that are respectively incident through the 54G and 54B are combined. The combined transmitted light is projected on a screen 57 through a lens 56 as image light.

Thus, an arbitrary color image is displayed on the screen 57.

[0010]

However, as shown in FIG. 7, the conventional liquid crystal projector uses the reflector 60 in order to effectively use the light generated by the light emitting section 51 emitting light. Is going to be incident on the dichroic prism 52 for color separation, but the divergent light B and C, which are diffused lights that cannot be converted into the parallel light A, are generated by the reflector 60 at present. is there.

For this reason, as shown in FIG. 8, for example, the parallel light A is incident on a parallel light area 70 which is a circumscribed circle of the liquid crystal panels 54R, 54G, 54B, and the divergent lights B, C are The light is incident on a divergent light region 71 which is a circular region surrounding the parallel light region 70. As can be seen from FIG. 7, even if the parallel light A is actually incident on the liquid crystal panels 54R, 54G and 54B, the parallel light A
This is about 60% of the whole, and the remaining 40% is
R, 54G and 54B are not incident. The divergent lights B and C correspond to 30% of the entire light incident on the dichroic prism 52 for color separation from the reflector 60, and are not incident on the liquid crystal panels 54R, 54G and 54B.

As described above, in the conventional liquid crystal projector, even if the reflector 60 is used, there is wasted light that does not enter the liquid crystal panels 54R, 54G, and 54B for the respective colors, so that the light is projected on the screen. The brightness of the image is insufficient, and it is difficult to recognize the image projected on the screen 57 without darkening the entire room where the screen 57 is provided.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and light generated when a light emitting section emits light can be incident on each of red, green, and blue liquid crystal panels without waste. It is an object of the present invention to provide a liquid crystal projector device capable of increasing the luminance of an image formed by image light projected on a projector.

[0014]

SUMMARY OF THE INVENTION According to the present invention, there is provided a liquid crystal panel in which light from a light source section having a parabolic mirror for reflecting light emitted from a light emitting section is incident on a liquid crystal panel, and an image generated by passing through the liquid crystal panel. In a liquid crystal projector device for projecting light onto a screen, an opening for passing the light from the light source unit as it is and entering the liquid crystal panel is provided to surround the opening, and diffused light from the light source unit is provided. A deflecting unit having a deflecting unit for deflecting light by refraction and entering the liquid crystal panel.

[0015]

In the liquid crystal projector according to the present invention, the light from the light source unit is incident on the liquid crystal panel through the opening of the deflecting unit, and the diffused light of the light from the light source unit surrounds the opening. To the liquid crystal panel via the deflecting unit provided as described above.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a liquid crystal projector according to the present invention will be described below with reference to the drawings. As shown in FIG. 1, the liquid crystal projector device according to the present embodiment includes a light emitting unit 1, a reflector 2 for deflecting diffused light diffusely emitted from the light emitting unit 1 into parallel light, and a Fresnel as a deflecting unit. An infrared cut filter 12 that is provided between the lens 3 and, for example, the reflector 2 and the Fresnel lens 3 and removes an infrared component from the incident light; and converts the incident parallel light into red (R), green (G), for example. , A dichroic prism 5 for color separation for separating light into blue (B) light. The light emitting section 1 and the reflector 2 constitute a light source section.

Further, the liquid crystal projector device according to the present embodiment includes a mirror 4a and a mirror 4b which reflect the red light among the lights of the respective colors separated by the dichroic prism 5 for color separation; A red liquid crystal panel 7R on which the red light is incident via the mirrors 4a and 4b, and mirrors 4c and 4d for reflecting the blue light among the lights of the respective colors decomposed by the dichroic prism 5. A blue liquid crystal panel 7B, into which the blue light is incident via the mirrors 4c and 4d, and a dichroic prism 5 for color separation.
And a green liquid crystal panel 7G into which the green light is incident among the lights of the respective colors decomposed by the above.

The liquid crystal projector device according to the present embodiment includes a color synthesizing dichroic prism 6 into which the transmitted light of each color generated by transmitting through the liquid crystal panels 7R, 7G, 7B of each color is incident. A lens 8 for projecting image light generated by the color synthesizing dichroic prism 6 on the screen 9 generated by synthesizing the transmitted lights of the respective colors, and a lens 8 for removing heat generated by the light emission of the light emitting unit 1 for air cooling, for example. Cooling device 1 such as a fan
0 and a power supply 11 for supplying power to the light emitting unit 1 and the like.

The reflector 2 is, for example, a parabolic mirror whose reflecting surface has a parabolic surface, and the light emitting section 1 is provided so as to be located at the focal point of the parabolic surface which is the reflecting surface of the reflector 2.

The Fresnel lens 3 has a substantially rectangular outer shape, for example, as shown in FIG. 2, and is provided with a circular opening 3a having a center point coincident with the center point of the Fresnel lens 3. ing. The size of the diameter of the opening 3a is slightly smaller than the inner diameter 2a of the reflector 2 shown by the dotted line in FIG. The other part of the Fresnel lens 3 than the opening 3a serves as a deflecting unit 3b for deflecting the incident divergent light into parallel light.

Such a Fresnel lens 3 is similar to that shown in FIG.
As shown in FIG. 5, the center of the opening of the reflector 2 and the center of the opening 3a of the Fresnel lens 3 coincide with each other with the infrared cut filter 12 interposed therebetween. Is provided.

The color separating dichroic prism 5, the green liquid crystal panel 7G, the color synthesizing dichroic prism 6 and the lens 8 are provided so that their respective center points coincide with the center point of the Fresnel lens 3.

In the description of the present embodiment, the Fresnel lens 3 shown in FIG. 2 is used as the deflecting means, but the deflecting means has a substantially circular outer shape as shown in FIG. Like the lens 3, the opening 30a has a substantially circular shape slightly smaller than the inner diameter 2a of the reflector 2, and the deflecting portion 30 is a portion other than the opening 30a.
The glass lens 30 having b may be used.

Next, the operation will be described. In this liquid crystal projector, the light emitting unit 1 is driven by the power supply 1. Thereby, the light emitting section 1 emits light. The light generated by the light emitting unit 1 emitting light is diffused light. The reflector 2 deflects the diffused light into parallel light and emits it. Light that cannot be deflected to parallel light by the reflector 2 (hereinafter referred to as divergent light) is generated. The parallel light and the divergent light are incident on the infrared cut filter 12, respectively. The infrared cut filter 12 removes an infrared component from the incident parallel light and divergent light. The parallel light from which the infrared component has been removed by the infrared cut filter 12 enters the opening 3a of the Fresnel lens 3 and
The divergent light is incident on the deflecting portion 3b of the Fresnel lens 3.

As described above, the opening 3a of the Fresnel lens 3 allows incident parallel light to pass through as it is.
Therefore, as shown in FIG. 4, the parallel light A is incident on the color separation dichroic prism 5 through the opening 3a of the Fresnel lens 3. On the other hand, the deflecting unit 3b of the Fresnel lens 3 corrects the divergence angle of the incident divergent light and emits it as parallel light. Therefore, as shown in FIG. 4, the divergent light incident on the deflecting unit 3b is corrected into parallel light, and is incident on the dichroic prism 5 for color separation.

As a result, as shown in FIG. 5, the parallel light A passing through the opening 3a is transferred to a parallel light area 20 which is an inscribed circle area of the liquid crystal panels 7R, 7G, 7B for each color described later. The parallel lights B and C that have been incident and deflected by the deflecting unit 3b into parallel lights are incident on a parallel light area 21 that is a circumscribed circle area of the liquid crystal panels 7R, 7G, and 7B.

Therefore, the liquid crystal panels 7R, 7R for the respective colors are used.
It is possible to increase the amount of parallel light incident on each of G and 7B.

Dichroic prism for color separation 5
Decomposes light incident through the Fresnel lens 3 into, for example, red (R), green (G), and blue (B) light. The red light of the light of each color decomposed by the dichroic prism 5 is incident on the red liquid crystal panel 7R via the mirrors 4a and 4b. The green light is directly incident on the green liquid crystal panel 7G, and the blue light is reflected by the mirror 4c and the mirror 4c.
The light is incident on the blue liquid crystal panel 7B via d.

The liquid crystal panels 7R, 7G, 7B for each of the above colors
Is controlled to display an arbitrary image by an image display circuit (not shown). For this reason, the light of each color corresponding to the above-mentioned arbitrary image is respectively transmitted to the liquid crystal panel 7 for each of the above-mentioned colors.
R, 7G and 7B are transmitted. The transmitted light of each color enters the dichroic prism 6 for color synthesis. Dichroic prism 6 for color synthesis
Synthesizes the transmitted light of each color which is incident through the liquid crystal panels 7R, 7G, 7B for each color. The combined transmitted light is projected on the screen 9 through the lens 3 as image light.

As described above, by using the Fresnel lens 3, the liquid crystal panels 7R, 7G,
It is possible to increase the amount of parallel light incident on each of the pixels 7B. Therefore, the amount of image light generated by the dichroic prism 6 for color synthesis and projected on the screen 9 can be increased, and the image projected on the screen 9 can be recognized even in a bright room. become.

As is clear from the above description, in the liquid crystal projector device according to the present embodiment, of the light emitted from the light source section, the parallel light is passed as it is, and the divergent light is corrected by correcting the divergence angle. By providing the Fresnel lens 3 that emits light as light, more parallel light can be incident on the liquid crystal panels 7R, 7G, 7B for each color, and thus the liquid crystal panels 7R, 7G, 7B for each color. The amount of image light generated from the transmitted light that has passed through can be increased.

Therefore, it is possible to increase the brightness of the image projected on the screen 9 and to realize a liquid crystal projector device capable of recognizing the image projected on the screen 9 even in a bright room. .

[0033]

According to the liquid crystal projector of the present invention, the light from the light source enters the liquid crystal panel through the opening of the deflecting means, and the diffused light out of the light from the light source passes through the opening. Since the light is incident on the liquid crystal panel via the deflecting unit provided so as to surround, more light can be incident on the liquid crystal panel. Therefore, the amount of image light generated from the transmitted light transmitted through the liquid crystal panel can be increased, and the luminance of the image projected on the screen can be increased.

Therefore, it is possible to realize a liquid crystal projector device that can recognize an image projected on the screen even in a bright room.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a liquid crystal projector device according to the present invention.

FIG. 2 is a schematic diagram showing a Fresnel lens provided as a deflection unit in the liquid crystal projector device according to the present invention.

FIG. 3 is a schematic view showing a glass lens provided as a deflecting unit in the liquid crystal projector device according to the present invention.

FIG. 4 is a schematic diagram for explaining the function of the Fresnel lens.

FIG. 5 is a schematic diagram for explaining how parallel light passing through the Fresnel lens is incident on a liquid crystal panel for each color.

FIG. 6 is a schematic diagram showing a configuration of a conventional liquid crystal projector device.

FIG. 7 is a schematic diagram for explaining light emitted from a light source unit.

FIG. 8 is a schematic diagram for explaining how light emitted from a light source unit of a conventional liquid crystal projector device enters a liquid crystal panel for each color.

[Explanation of symbols]

1 Light-emitting unit 2 Reflector 3 Fresnel lens 3a Opening 3b Deflecting unit 4a-4d Mirror 5 Dichroic prism for color separation 6 Dichroic prism for color synthesis 7R: red liquid crystal panel 7G: green liquid crystal panel 7B: blue liquid crystal panel 8.・ ・ ・ ・ ・ ・ ・ ・ ・ Lens 9 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Screen 10 ・ ・ ・ ・ ・ ・ ・ ・ ・ Cooling device 11 ・ ・ ・ ・ ・ ・ ・ ・ ・ Power supply 12 ・ ・ ・ ・ ・ ・····· Infrared cut filter 30 ········ Glass lens 30a ······ Opening 30b ······· Deflection

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G03B 33/12

Claims (1)

(57) [Claims] 1. A liquid crystal projector for projecting light from a light source unit having a parabolic mirror for reflecting light emitted from a light emitting unit to a liquid crystal panel, and projecting image light generated through the liquid crystal panel onto a screen. In the device, an opening through which light from the light source unit passes as it is and enters the liquid crystal panel, and is provided so as to surround the opening, and the light from the light source unit is deflected by refraction to diffuse light. A liquid crystal projector device comprising: a deflecting unit having a deflecting unit for entering a liquid crystal panel.