JP2003107579A - Liquid crystal projector device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the contrast of a liquid crystal projector device. SOLUTION: An attenuation plate 22 having color selectivity for selectively attenuating at least one color light component of RGB light included in the light emitted by a lamp 2 according to visual angle characteristics of a liquid crystal panel is arranged nearby a condenser lens 8 to attenuate part of the RGB light emitted by the lamp 2, thereby improving the contrast without any deterioration in picture quality due to lighting unevenness.

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 device, and is suitable for improving the contrast of a projected image projected on a screen.

[0002]

2. Description of the Related Art There is known a liquid crystal projector device capable of optically modulating light output from a light source by, for example, a transmissive liquid crystal panel to form image light, and enlarging and projecting the image light on a screen for display. Has been. For example, in a liquid crystal projector device capable of displaying a color image on a screen, a light beam emitted from a light source and containing red (R), green (G), and blue (B) color light components is emitted for each color light. An illumination optical system that separates and focuses each on a predetermined optical path, a liquid crystal panel (light valve) that is provided for each color light, and that modulates each color light that is separated by the illumination optical system, and a light by each liquid crystal panel And a light combining section for combining the modulated color lights. Then, the color image combined by the light combining unit is enlarged and projected on the screen by the projection lens to display the color image on the screen.

[0003]

By the way, the liquid crystal panel provided in the liquid crystal projector device as described above is
It has a so-called viewing angle characteristic in which the contrast changes depending on the incident angle of the light beam incident from the illumination optical system. Further, in the liquid crystal projector device, the light ray incident angle from the illumination optical system to the liquid crystal panel has any angle within a range of, for example, about ± 10 ° to 15 ° (deg), and the light intensity is different. To be taken.

Therefore, in the liquid crystal projector device, the contrast of the color image displayed on the screen is determined by the viewing angle characteristics of each liquid crystal panel and the incident angle of the light beam incident from the illumination optical system on each liquid crystal panel. And the light intensity distribution indicated by the light intensity and the viewing angle characteristics of each liquid crystal panel.

The viewing angle characteristics of the liquid crystal panel will be described with reference to FIG. FIG. 7A is a diagram showing the viewing angle characteristics of a certain liquid crystal panel, and FIG. 7B is a diagram showing the measurement conditions of the viewing angle characteristics shown in FIG. 7A.

The viewing angle characteristics of the liquid crystal panel 100 shown in FIG. 7A are shown by a contour diagram showing the change in contrast in the liquid crystal panel. The contrast of the liquid crystal panel is, for example, a brightness level of 0 IRE and 100 IRE.
It is defined by the ratio with the luminance level of.

The viewing angle characteristics of the liquid crystal panel 100 shown in FIG. 7A are as shown in FIG. 7B, the XY plane (panel surface) of the liquid crystal panel 100 and the Z orthogonal to the panel surface.
A measurement position P where the axis intersects, a position tilted by θ ° (θ = 0 ° to 10 °) from the Z axis on the emission surface side (front surface side) of the liquid crystal panel is an observation position Q, and the incident surface side of the liquid crystal panel 100. On the (rear side), the light source 101 having a constant light intensity is arranged on the extended line of the broken line connecting the observation position Q and the measurement position P, and the observation position Q is set to the Y axis (φ = φ) with the Z axis as the rotation axis.
It is obtained by rotating φa (φa = 0 ° to 360 °) from 0 °.

From the viewing angle characteristics shown in FIG. 7A, it can be seen that the liquid crystal panel 100 has the best contrast in the area A near the center, and the contrast decreases as the distance from the area A increases. That is, it can be seen that the contrast decreases as the angle θ between the Z axis and the observation position Q increases. This means that in the liquid crystal panel 100 shown in FIG. 7A, the contrast decreases as the incident angle θ of the light beam from the light source 101 increases. It is also found that the contrast of the liquid crystal panel 100 changes when the observation direction φa of the liquid crystal panel 100 is changed as a two-dimensional plane of XY. In other words, this means that the contrast of the liquid crystal panel 100 changes even when the direction of incident light from the light source 101 changes.

In particular, the liquid crystal panel 1 shown in FIG. 7 (a).
00 has a relatively small change in contrast when viewed from the Y-axis direction (φa = 0 °, 180 °), even if the observation angle (light ray incident angle) θ becomes large, but the X-axis direction (φa = It can be seen that when viewed from 90 ° and 270 °), the contrast tends to deteriorate as the observation angle (light incident angle) θ increases. Furthermore, when observing the liquid crystal panel 100 from the lower side, that is, 180 °
When observed from a direction of up to 360 °, it can be seen that the contrast is significantly deteriorated as the observation angle (light ray incident angle) θ is increased.

Therefore, when a liquid crystal projector device is constructed by using the liquid crystal panel 100 having the viewing angle characteristics shown in FIG. 7A, the influence of the contrast deterioration caused by the light beam incident from above the liquid crystal panel. By
There is a drawback that the contrast of the projected image displayed on the screen is deteriorated.

Therefore, the inventor of the present application has proposed to arrange a light shielding plate in a part of the optical path of a certain color light (for example, blue light B) in order to improve the contrast (Japanese Patent Application No. 2000-242242). 2000-38183).

However, Japanese Patent Application No. 2 proposed by the present inventor
000-38183 (hereinafter referred to as prior art)
In case of limiting the luminous flux of only one color,
It is necessary to arrange the attenuating plate at a position where the red, green and blue lights are monochromatic. As a place where the red, green, and blue light fluxes are monochromatic, there is the vicinity of the liquid crystal panel.However, if an attenuating plate is placed at this place, the attenuating plate causes uneven illumination of the liquid crystal panel, Image quality deterioration (luminance unevenness) on the screen will occur.

In order to prevent uneven illumination on the liquid crystal panel, for example, an attenuating plate may be arranged near the multi-lens array. In the vicinity of the multi-lens array, red, green, and blue light beams are emitted. Since they are in a mixed state (white), if an attenuator is placed at this position, all three colors will be attenuated by the attenuator, which will result in a decrease in the required amount of colored light. become.

Further, for example, when an attenuating plate is arranged in the vicinity of the multi-lens array and it is desired to attenuate the light flux incident on the liquid crystal panel from above, the attenuating plate is usually arranged above the multi-lens array. However, in the case of an illumination optical system in which only the optical path of a certain colored light is an unequal length system, the relay lens arranged in the unequal length optical path inverts the light beam vertically and horizontally, The light flux incident on the liquid crystal panel from below is attenuated. In other words, the light flux in the portion with good viewing angle characteristics will be limited.

As described above, in the previously proposed prior art, when the attenuating plate is arranged in the vicinity of the liquid crystal panel, there is a problem that the attenuating plate causes uneven illumination of the liquid crystal panel, and in the vicinity of the multi-lens array. If an attenuating plate is placed, it affects not only the desired color light but also other color lights, resulting in problems such as loss of the required amount of color light and the elimination of light rays that should not be removed. was there.

Therefore, the present invention has been made in view of the above points, and improves the contrast without deteriorating the image quality of the projected image due to the uneven illumination of the liquid crystal panel and without affecting other colored light. It is an object of the present invention to provide a liquid crystal projector device capable of performing the above.

[0017]

In order to achieve the above object, a liquid crystal projector device of the present invention has a light source which emits light rays containing red, green and blue color light components, and a predetermined light ray which is emitted from the light source. From the liquid crystal panel, an illumination optical system capable of converging into the optical path of each of the above and separating each color light component, and a liquid crystal panel for optically modulating each color light separated by the illumination optical system and converged to a predetermined optical path. Illumination for attenuating a part of light rays emitted from a light source, a color synthesizing means for synthesizing output lights of respective colors to be output, a projection lens for projecting an optical image synthesized by the color synthesizing means on a screen. An attenuating plate having a color selectivity that is arranged at a predetermined position of the optical system and selectively attenuates at least one of the color light components emitted from the light source.

According to the present invention, at least any one of the RGB color light components contained in the light emitted from the light source.
Uneven illumination occurs on the liquid crystal panel by arranging an attenuator that can selectively attenuate one of the three color light components so as to attenuate part of the luminous flux emitted from the light source in the optical path of the light emitted from the light source. It is possible to improve the contrast without affecting the other color lights.

[0019]

1 is a diagram showing a configuration of an optical system of a liquid crystal projector device according to an embodiment of the present invention. The liquid crystal projector device 1 shown in FIG.
A three-plate type liquid crystal projector device is provided in which a liquid crystal panel for RGB light is provided for each color light of (red), G (green), and B (blue). In FIG. 1, a lamp 2, which is a light source, includes a light emitting unit 2 a that emits light (white light) containing color light components of three primary colors (RGB), and a light emitting unit 2 for example.
The reflector 2b reflects the light of a, and the light emitting portion 2a is arranged at the focal position of the reflector 2b.

In this case, in the lamp 2, the light emitted from the light emitting portion 2a is reflected by the reflector 2b to be emitted as light substantially parallel to the optical axis from the opening. With respect to the light emitted from the lamp 2, unnecessary light rays in the infrared region and the ultraviolet region are cut (cut) by an IR-UV cut filter 3 provided in the subsequent stage as an illumination optical system, and only effective light rays are mirrored. The direction of travel is bent, for example, by 90 ° by 4 and is guided to the multi-lens array.

As the multi-lens array, a first multi-lens array 5 and a second multi-lens array 6 are provided. First and second multi-lens arrays 5, 6
Has a plurality of lens cells having an outer shape ratio substantially equal to the aspect ratio of the effective apertures of the liquid crystal panels 13, 18, and 27, and the lens cells of the first multi-lens array 5 and the second multi-lens array. The lens cells of are arranged so as to correspond to each other.

The unpolarized light (P-polarized wave + S-polarized wave) emitted from the first and second multi-lens arrays 5 and 6 is transmitted by the P / S integrator 7 to the liquid crystal panel 1.
It is converted into a polarized wave (for example, a P polarized wave) in a predetermined deflection direction corresponding to 3, 18, and 27 and is incident on the plano-convex lens 8 which is the first condenser lens.

The plano-convex lens 8 is used for each liquid crystal panel 13, 1.
Along with the plano-convex lenses 11, 16 and 25 which are the second condenser lenses arranged near the lenses 8 and 27, the light flux that has passed through each lens cell of the second multi-lens array 6 is condensed to form the liquid crystal panel 13 , 18, 27 are provided to be superimposed on each other.

The light beam condensed by the plano-convex lens 8 is incident on the dichroic mirror 9. Dichroic mirror 9
Is configured to reflect only the light flux of the red light R included in the light flux incident from the plano-convex lens 8 and to transmit the light fluxes of the green light G and the blue light B. This dichroic mirror 9
Only the light flux of the red light R reflected by is bent by 90 ° by the mirror 10 and guided to the liquid crystal panel 13 for R light through the plano-convex lens 11 and the polarizing plate 12.

On the other hand, the luminous fluxes of the green light G and the blue light B which have passed through the dichroic mirror 9 are incident on the dichroic mirror 15. The dichroic mirror 15 is configured to reflect only the light flux of the green light G and transmit the light flux of the blue light B. Only the light flux of the green light G reflected by the dichroic mirror 15 is reflected by the plano-convex lens 16 and the polarizing plate. 1
It is led to the liquid crystal panel 18 for G light via 7. Also,
The light flux of the blue light B transmitted through the dichroic mirror 15 is guided to the liquid crystal panel 27 for B light through the first relay lens 20, the mirror 21, the second relay lens 23, the mirror 24, the plano-convex lens 25, and the polarizing plate 26. To be punished.

Therefore, in the liquid crystal projector device 1 of the present embodiment, comparing the optical path lengths of the RGB light components,
The optical path length of the blue light B is an unequal length system different from the optical path lengths of the red light R and the green light G.

Then, liquid crystal panels 13, 1 for RGB light
The light fluxes of the respective color lights that have been light-modulated in 8 and 27 are passed through the polarizing plates 14, 19 and 28, and dichroic prism 29.
Is incident on. The dichroic prism 29 has, for example, an outer shape formed by joining a plurality of glass prisms, and interference filters 29a, 29b having predetermined optical characteristics are formed on the joining surface of each glass prism.

In the example shown in FIG. 1, the interference filter 29 is used.
a reflects, for example, the blue light B from the liquid crystal panel 27,
The green light G from the liquid crystal panel 18 and the red light R from the liquid crystal panel 13 are transmitted. The interference filter 29b reflects the red light R from the liquid crystal panel 13 and transmits the green light G from the liquid crystal panel 18 and the blue light B from the liquid crystal panel 27.

Therefore, in the dichroic prism 29 shown in FIG. 1, the red light R is reflected by the interference filter 29b toward the projection lens 30, and the blue light B is reflected by the interference filter 29a toward the projection lens 30. Further, the green light G reaches the projection lens 30 by passing through the interference filters 29a and 29b. As a result, the RGB color lights are combined into one optical axis, and the combined image is projected from the projection lens 30 onto a screen (not shown).

By the way, as described above, the contrast of the image projected on the screen of the liquid crystal projector device depends on the viewing angle characteristic of each liquid crystal panel that optically modulates RGB light and the incidence from the illumination optical system to the liquid crystal panel. It is determined by the total contrast obtained by superimposing the light intensity distribution (light incident angle and light intensity) of the light rays to be generated. Therefore, from the illumination optical system to each liquid crystal panel,
By limiting the light rays incident at an angle, the contrast of each color light can be improved.

Therefore, the liquid crystal panels 13, 18 provided in the liquid crystal projector device 1 according to the present embodiment,
27 is, for example, the liquid crystal panel 10 shown in FIG.
Assuming that the liquid crystal panel has a viewing angle characteristic similar to that of 0 and deterioration of the contrast is remarkable when the liquid crystal panel is observed from the lower side, each of the liquid crystal panels 13,
By limiting the luminous fluxes that are incident from above 18 and 27 at an angle, it is possible to improve the contrast of the RGB color lights.

Here, the prior art proposed by the present inventor,
In order to clarify the difference from the present invention described later, the prior art will be specifically described with reference to FIG. First, as a premise, the liquid crystal panels 13, 18, 27
In the same manner as the liquid crystal panel 100 shown in FIG. 7A, the viewing angle characteristic with respect to a light ray from above is poor, and therefore it is desired to limit the light flux incident at an angle from above. Then, when adjusting the white balance, the light amount of the green light G has a margin and the light amount of the green light G may be limited, but the light amounts of the red light R and the green light G are not desired to be limited. In addition, the optical path length of the blue light B is an unequal length system from the optical path lengths of the other two colors.

In this case, since it is desired to improve the contrast of the green light G, according to the prior art, an attenuating plate is provided in the optical path behind the dichroic mirror 15 in which the light from the lamp 2 is monochromatic only for the green light G. Will be placed. However, in this case, the arrangement position of the attenuating plate is too close to the liquid crystal panel 17, which causes uneven illumination on the liquid crystal panel 17. Therefore, the liquid crystal panel 17
The attenuating plate is arranged near the second multi-lens array 6 which is not near, but at this position, the light rays from the lamp 2 are in a state (white) in which RGB color lights are mixed. Therefore, if the attenuating plate is arranged at this position, all the RGB color lights will be attenuated. That is, the red light R and the blue light B, which should not be restricted, are also restricted by the attenuating plate. In particular, in the liquid crystal projector device shown in FIG. 1, the optical path of the blue light B is an unequal length system, and the vicinity of the second multi-lens array 6 is the lower part of the vicinity of the second relay lens 23. In this case, the light rays from below having a good viewing angle characteristic are limited.

Therefore, also in this embodiment, as in the prior art, the plano-convex lens 8 provided in the illumination optical system is used.
In the vicinity of (or the multi-lens array), an attenuating plate 22 is arranged so as to attenuate a part of a light beam emitted from the lamp 2 that is incident on the liquid crystal panel at an angle from above, for example. However, in the present embodiment, the attenuating plate 22 arranged in the vicinity of the plano-convex lens 8 is provided with at least one of the RGB color lights emitted from the lamp 2 (eg, green light G). Is characterized by being formed by a filter having color selectivity capable of selectively attenuating.

That is, since the light rays from the lamp 2 passing through the plano-convex lens 8 are mixed with the respective RGB color light components, in the present embodiment, the attenuating plate 22 outputs only a specific color light (for example, green light G). By forming the filter by a filter that can be selectively attenuated, the light amount loss of the other two color lights (red light R and blue light B) is minimized.

The structure of the attenuating plate 22 provided in the liquid crystal projector device according to the present embodiment and its position will be specifically described below. Note that the liquid crystal panels 13, 18 and 27 are shown in FIG.
It is assumed that the liquid crystal panel 100 shown in FIG. It should be noted that the viewing angle characteristics of the liquid crystal panel are actually different for each liquid crystal panel. Although a detailed description of the factor causing the viewing angle characteristic in the liquid crystal panel is omitted, it is attributed to the alignment direction of the liquid crystal molecules forming the liquid crystal panel, that is, the rubbing direction.

2 and 3 are views showing an example of the arrangement position of the attenuation plate 22 in the case of improving the contrast of the green light G in the liquid crystal projector device 1 according to the present embodiment. It should be noted that the same parts as those in FIG.

First, as shown in FIG. 2, the green light G contained in the light beam emitted from the lamp 2 includes the IR-UV cut filter 3, the first and second multi-lens arrays 5, 5.
6. Since the liquid crystal panel 17 reaches the liquid crystal panel 17 via the plano-convex lenses 8 and 16, when the liquid crystal panel 17 has the viewing angle characteristic as shown in FIG. Further, if the attenuation plate 22 is arranged so as to attenuate only the luminous flux of the green light G incident from above the liquid crystal panel 17 at a required angle, the contrast of the green light G can be improved.

Therefore, in this case, the attenuating plate 22 is formed by, for example, a G reflection trimming filter capable of attenuating only the green light G and transmitting the other two color lights (red light R and blue light B). This damping plate 22 is shown in FIG.
As shown in (b), it is arranged on the incident side of the plano-convex lens 8 so as to attenuate part of the green light G emitted from the lamp 2.

In this case, the attenuation range d of the green light G by the attenuation plate 22 shown in FIG.
It may be set as appropriate according to the viewing angle characteristic (contrast). However, in reality, the light amount of the green light G decreases as the attenuation range d by the attenuating plate 22 increases, so that the light shielding range d by the attenuating plate 22 is the contrast and the light amount of the projection image projected on the screen. It will be set appropriately in consideration of the above.

FIG. 4 shows the spectral transmittance characteristics of the G reflection trimming filter used in the attenuating plate 22 for attenuating the green light G described above. As can be seen from FIG. 4, the G reflection trimming filter has a wavelength of, for example, 430 nm to 49 nm.
Blue light B of about 0 nm and a wavelength of 640 nm to 770 n
The wavelength is 4 with almost no attenuation of the red light R of about m.
It is possible to attenuate only the green light G of about 90 nm to 550 nm.

Therefore, in the liquid crystal projector device 1 of the present embodiment, if the attenuation plate 22 formed by the G reflection trimming filter having the spectral transmittance characteristic as shown in FIG. 4 is arranged near the plano-convex lens 8. , Only the green light G can be attenuated without attenuating the light amounts of the red light R and the blue light B included in the light emitted from the lamp 2, and the contrast of the green light G can be improved by the attenuation plate 22. Will be possible. Further, since it does not affect the blue light B, it also has an advantage that it does not affect the up / down / left / right inversion problem in the unequal length system.

Further, in this case, since the attenuation plate 22 is arranged near the plano-convex lens 8 which is separated from the liquid crystal panel 17, the attenuation plate 22 is arranged on the liquid crystal panel as when the light shielding plate is arranged near the liquid crystal panel 17. Since the illumination unevenness does not occur, the image quality of the projection image projected on the screen does not deteriorate.

Here, the inventor of the present application verified the contrast by the attenuation plate 22. An example of the verification result is shown in FIG. Also in this case, the attenuating plate 22 is formed by the G reflection trimming filter described above. Figure 5 (a)
In FIG. 5B, the measurement results of the light amounts and the contrasts of the RGB color lights without the attenuation plate 22 are shown. In FIG. 5B, the light amounts and the contrasts of the RGB color lights with the attenuation plate 22 disposed near the convex lens 8 are shown. 5C shows the measurement results of the light amount and the contrast of each color light of RGB by disposing the light shielding plate instead of the attenuation plate 22 in FIG. 5C.

As can be seen by comparing the measurement results of FIGS. 5A and 5B, when the attenuation plate 22 is arranged near the convex lens 8, the light amount of the green light G is reduced by about 10%. It was found that the contrast of the green light G can be improved. It was also confirmed that there is almost no loss of light amount of red light R and blue light B due to the attenuation plate 22.

According to the liquid crystal projector device of the present embodiment, the contrast between the red light R and the blue light B is improved, if not so much as the contrast of the green light G. This is because the transmittances of the red light R and the blue light B in the G reflection trimming filter forming the are not 100%.

From the measurement results shown in FIGS. 5 (b) and 5 (c), when a light shielding plate is arranged near the plano-convex lens 8, the contrast can be improved for each of the RGB color lights, but the color is red. It can be seen that the light amounts of the light R and the blue light B are reduced.

In the measurement result of FIG. 5 (c), the improvement of the contrast of the blue light B is smaller than that of the red light R and the green light G, in the liquid crystal projector device of the present embodiment. Since B is an unequal length system, when a light shielding plate is arranged above the plano-convex lens 8, not the blue light B which is incident from above the liquid crystal panel 27, but the blue light which is incident from below the liquid crystal panel 27. This is because the blue light B that is generated is limited.

Further, in the present embodiment described so far, in order to improve the contrast of the green light G, only the green light G included in the light beam emitted from the lamp 2 is attenuated in the vicinity of the plano-convex lens 8. Although the case where the attenuating plate 22 is arranged has been taken as an example, the red light R and the blue light B can be attenuated by the same configuration to improve the contrast.

For example, when the contrast of the red light R is improved, the attenuation plate 22 formed by a filter capable of attenuating only the red light R near the plano-convex lens 8.
Should be placed. To improve the contrast of the blue light B, an attenuation plate 22 formed by a filter capable of attenuating only the blue light B may be arranged near the plano-convex lens 8.

The arrangement position of the attenuation plate 22 for improving the contrast of the red light R is, for example, the liquid crystal panel 13.
In the case of limiting the incident light incident from the upper side of the above, it may be arranged above the plano-convex lens 8 as in the case of the green light G described above.

On the other hand, the arrangement position of the attenuating plate 22 for improving the contrast of the blue light B is, for example, when the incident light incident from the upper side of the liquid crystal panel 13 is limited. In the liquid crystal projector device 1 of the embodiment, since the blue light B is an unequal length system, the blue light B is arranged at a position where the above-mentioned arrangement position of the green light G (or the red light R) and the vertical (horizontal) position are reversed. It will be.

FIG. 6 shows an example of the arrangement position of the attenuation plate 22 when the contrast of the blue light B is improved.
It should be noted that the same parts as those in FIG. As shown in FIG. 6, the optical path of the blue light B emitted from the lamp 2 is incident on the liquid crystal panel 27 through the optical path as shown in FIG. It is understood that when limiting the blue light B generated in the vicinity of the plano-convex lens 8, the attenuating plate 22 may be arranged below the plano-convex lens 8.

In this embodiment, the case where only the luminous flux of the green light G incident from the upper side of the liquid crystal panel is attenuated is described as an example, but this is merely an example,
It goes without saying that the attenuation plate 22 may be arranged so as to attenuate the light rays incident from the lower side of the liquid crystal panel 17 or the left and right directions according to the viewing angle characteristics of the liquid crystal panel.

Further, in the present embodiment, the damping plate 2
Although any one of the RGB color lights is limited by 2 according to the example, this is merely an example, and the plano-convex lens may be used depending on the viewing angle characteristics of the RGB liquid crystal panels 13, 18, and 27. Attenuator plates 22 for limiting the R light, the G light, and the B light may be arranged in the vicinity of 22, respectively.

Furthermore, in the present embodiment, the attenuating plate 22 is arranged near the plano-convex lens 8, but this is merely an example, and the attenuating plate 22 is positioned near the multi-lens array 6 as the present invention. The point is that it may be arranged at a position where a part of the luminous flux emitted from the lamp 2 to each liquid crystal panel can be attenuated according to the viewing angle characteristics of the liquid crystal panel.

Furthermore, in the present embodiment, a three-plate type liquid crystal projector device has been described as an example, but this is merely an example, and the present invention is limited to such a three-plate type liquid crystal projector device. Not a thing.

[0058]

As described above, the liquid crystal projector device of the present invention has a color selectivity that selectively attenuates at least one color light component of each color light included in the light emitted from the light source. By disposing the attenuating plate at a predetermined position of the illumination optical system and attenuating a part of the light flux emitted from the light source, the projection image projected on the screen can be projected without deterioration of the image quality of the projection image due to uneven illumination. It becomes possible to improve the contrast.

Therefore, in the liquid crystal projector device of the present invention, for example, after adjusting the white balance,
When the light quantity of a certain color light has a margin more than the light quantity of another color light, it is possible to improve the contrast after white balance without reducing the light quantity of the projected image. Also,
When it is necessary to reduce the amount of light of a certain color light when adjusting the white balance, if an attenuation plate is arranged according to the viewing angle characteristics of the liquid crystal panel corresponding to the certain color light, the amount of light can be limited. The contrast can be improved at the same time as the white balance is adjusted.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of an optical system of a liquid crystal projector device according to an embodiment.

FIG. 2 is a diagram showing an example of an arrangement position of an attenuation plate when attenuating green light.

FIG. 3 is a diagram showing an example of an arrangement position of an attenuation plate when attenuating green light.

FIG. 4 is a diagram showing characteristics of a G reflection trimming filter used as an attenuating plate.

FIG. 5 is a diagram showing measurement results of contrast and light amount.

FIG. 6 is a diagram showing an example of an arrangement position of an attenuating plate when attenuating blue light.

FIG. 7 is a diagram for explaining viewing angle characteristics of a liquid crystal panel.

[Explanation of symbols]

1 liquid crystal projector device, 2a light emitting part, 2b reflector, 2 lamp, 3 IR-UV cut filter,
4 10 21 24 mirror, 5 6 multi-lens array, 7 P / S integrator, 8 11 16
25 (condenser lens) Plano-convex lens, 9 15 dichroic mirror, 12 14 1719 26 2
8 polarizing plate, 13 18 27 liquid crystal panel, 20 2
3 relay lens, 22 light shield, 29a 29b interference filter, 29 dichroic prism, 30 projection lens

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03B 21/14 G03B 21/14 A

Claims (4)

[Claims] 1. A light source that emits light rays containing red, green, and blue color light components, and an illumination that can focus the light rays emitted from the light source on a predetermined optical path and separate each color light component. An optical system, a liquid crystal panel that individually modulates the respective color lights that are separated by the illumination optical system and converged to a predetermined optical path, and a color combining unit that combines the output lights of the respective colors output from the liquid crystal panel, A projection lens for projecting the optical image synthesized by the color synthesizing means onto a screen, and a predetermined position of the illumination optical system so as to attenuate a part of the light beam emitted from the light source, and the light emitted from the light source. An attenuating plate having a color selectivity for selectively attenuating at least one of the color light components to be generated, the liquid crystal projector device. 2. The liquid crystal projector according to claim 1, wherein the attenuating plate selects a color light component to be attenuated according to a viewing angle characteristic of the liquid crystal panel provided for each color light. apparatus. 3. The liquid crystal projector device according to claim 1, wherein the attenuating plate is arranged near a first condenser lens provided in the illumination optical system. 4. The liquid crystal projector according to claim 1, wherein the attenuating plate sets an attenuation range for attenuation according to a viewing angle characteristic of the liquid crystal panel provided for each color light. apparatus.