JPH0980371A - Projection type color liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a brighter display without increasing the luminance of a light source, reducing the light source for the improvement of parallelism, or increasing the diameter of a spot incident on each pixel of a liquid crystal display element. SOLUTION: For each of pieces of luminous flux which has a different wavelength range and is made incident at an angle of incidence prescribed in a 1st plane corresponding to the wavelength, a liquid crystal display element 12 which performs optical modulation processing for every luminous flux is provided, and 1st and 2nd luminous flux groups for projection are generated by a rotary elliptic surface mirror 2, a polarization beam splitter 13, etc., from the light of a white light source 1, and the 1st and 2nd luminous flux groups for projection are made incident on the liquid crystal display element 12 so that the optical axes of two pieces of luminous flux in each group having the same wavelength range are at a constant angle in a 2nd plane different from the 1st plane and the angles of incidence of pieces of luminous flux with respective wavelengths on the liquid crystal display element 12 are mutually different angles of incidence prescribed in the 1st plane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type color liquid crystal display device, and more particularly to effective use of light from a light source used as projection light in a single plate type liquid crystal display device.

[0002]

2. Description of the Related Art A projection type television using a liquid crystal display element has been developed as an alternative to an image display device of the type which projects an image displayed on a cathode ray tube on a screen. As a projection type color image display device using such a liquid crystal display element, there is a single plate type using one liquid crystal display element as disclosed in Japanese Patent Laid-Open No. 60538/1992, which has an optical system. It is known to be suitable for simple and compact systems.

FIG. 7 is a diagram showing a configuration of a color liquid crystal display device which is an example of such an image display device. In the figure, reference numeral 200 denotes a color liquid crystal display device having a transmissive liquid crystal display element 12 and its white light source 1, and the light emitted from the white light source 1 is arranged so that its first focus coincides with the position of the light source. The light is reflected by the spheroidal mirror 2 and focused on the second focal point of the spheroidal mirror.

The light focused on the second focal point is made into a divergent light by making the angular distribution of the light uniform by the integrator 11 arranged near the second focal point, and the light is collimated by the condenser lens 3. . The collimated light is separated into three primary colors of red, green, and blue by dichroic mirrors 4R, 4G, and 4B that selectively reflect red, green, and blue light, respectively. It is incident on each picture element corresponding to each color inside.

Here, each liquid crystal display element 12 is arranged on a liquid crystal display panel 20 that modulates incident light based on a display signal, and is arranged on the light incident side, and the incident light of each color is displayed on the corresponding picture element of the liquid crystal panel 20. Microlens array 10 for focusing light on
And an incident side polarization plate 8 arranged on the light incidence side of the microlens array 10 and an emission side polarization plate 9 arranged on the light emission side of the liquid crystal display panel 20.

FIG. 8 is a schematic sectional view showing the detailed structure of the liquid crystal display panel 20.

The liquid crystal display panel 20 has a structure in which a liquid crystal layer 30 is sandwiched between a pair of substrates 33 and 26 arranged so as to face each other. A plurality of picture element electrodes 21 are arranged in a matrix on the surface of one of the two substrates (hereinafter referred to as an active matrix substrate) 33. Further, on the substrate 33, a signal line 24 is provided corresponding to each column (or each row) of the picture element electrodes, and a gate line is provided corresponding to each row (or each column) of the picture element electrodes. Has been. Further, on the substrate 33, a thin film transistor (T) for driving each pixel electrode 21 is provided.
FT) 22 and an auxiliary capacitor 23 are provided, and each T
The gate 25 of the FT 22 is connected to the corresponding gate line and its source is connected to the corresponding signal line 24. The drain of the TFT is connected to the corresponding pixel electrode 21 and one electrode of the corresponding auxiliary capacitor 23. A potential at the same level as that of a counter electrode described later is applied to the other electrode of the auxiliary capacitance 23. Incidentally, 22a is a semiconductor layer which constitutes the TFT 22, and 22b is a gate insulating film.

Further, this active matrix substrate 33
A counter electrode 27 and a light-shielding film 28 are sequentially formed on the inner surface of the counter substrate 26 facing each other via the liquid crystal layer 30, and the light-shielding film 28 has an opening (a pixel opening) at a position facing the pixel electrode 21. ) 32 is formed. Here, the both substrates 3
As the liquid crystal layer 30 enclosed between 3 and 26, for example, a twisted nematic aligned liquid crystal layer is used. Further, here, one picture element is the picture element electrode 2
1, a TFT 22, a storage capacitor 23 and the like.

FIG. 9 is a schematic view showing a cross-sectional structure of the liquid crystal display panel 20 and the microlens array 10 which constitute the liquid crystal display element 12. As shown in FIG. 9, the microlens array 10 is composed of a plurality of microlenses 10a. The incident angles of the respective colors with respect to the respective microlenses 10a are set so that the condensed spots of the light fluxes of the respective colors are formed only on the picture element openings 32 of the corresponding colors. Here, the microlens array 1
Reference numeral 0 indicates that a plurality of hexagonal microlenses 10a in which the outer peripheral portions of the spherical lenses are fused with each other are produced by using the ion exchange method, and the relative arrangement between the microlenses 10a and the pixel array is shown. The physical relationship is shown in FIG.

Specifically, in the liquid crystal display panel 20, the picture elements corresponding to each color are repeatedly arranged in the order of red, green, and blue for each horizontal line of the display screen, corresponding to each picture element. The display area to be turned is an area inside the opening portion (picture element opening portion) 32 of the light shielding film 28. And the picture element opening 3
The array of 2 is an array in which square blocks are arranged vertically and horizontally and laterally shifted by half each of the widthwise dimensions, and each hexagonal microlens has its optical axis. The center is aligned with the center of the green picture element.

With the above dichroic mirror, red, green,
Of the incident light of red, green, and blue reflected at a predetermined angle for each color of blue, only P-polarized light is transmitted through the P-polarized transmissive polarizing plate 8, and, for example, S-polarized light of the incident light is It is absorbed by the polarizing plate 8.

Then, the green P-polarized light is incident perpendicularly on the microlens array 10 to form a focused spot in the green G pixel 32, and the red and blue P-polarized lights are the green P-polarized light. The red R picture element 32 and the blue B picture, which are incident on the microlens array 10 from the directions tilted to the left and right with respect to the light (up and down on the paper surface of FIG. 9) and are arranged on the left and right of the green picture element, respectively. A spot is formed in the element 32.

As described above, in the above conventional liquid crystal display device,
The light flux of each color is condensed on each of the red, green, and blue picture elements in one liquid crystal display element 12, and the light transmitted through each picture element is the polarizing plate 9, the field lens 5, and the projection lens 6.
A color image is displayed by being projected on the screen 7 via.

[0014]

However, in the above-mentioned conventional projection type color liquid crystal display device, light is incident on the liquid crystal display element when the illumination light has poor parallelism or in a direction different from the expected direction. In this case, the contrast of display and the color purity may be lowered.

Further, of the light condensed by the microlens array 10, the light having a poor parallelism which protrudes from the size of the pixel aperture 32 does not pass through the liquid crystal display element 12. Therefore, it is necessary to improve the parallelism of the illumination light as much as possible.

For example, the pixel pitch is 100 μm both vertically and horizontally.
m, the size of the pixel opening 32 is 50 μm in the vertical direction and 70 μ in the horizontal direction.
In the case of a 3-inch panel having m, the number of picture elements is 450 vertically and 600 horizontally, the focal length of the microlens array 10 is
A distance corresponding to a thickness of 1.1 mm (n = 1.53) of the counter substrate 26 (distance in air = 1.1 mm / 1.53 =
0.72 mm), the permissible amount of parallelism of the light incident on the opening of the green picture element is ± tan ^-1 (2) in the vertical direction of the picture element.
5/720) = ± 2.0 °, lateral direction = ± tan ⁻¹ (35
/720)=±2.8°. In addition, the light incident on the opening of the red or blue picture element has a direction of the principal ray of the parallel light flux of ± tan ^-1 (100/720) =
The inclination of ± 8 ° and the allowable degree of parallelism of light are the same as the vertical direction of the picture element = ± 2.0 ° and the horizontal direction = ± 2.8 °.

On the other hand, a metal halide lamp having a light source of 250 W and an arc length of 3.0 mm was used as the light source, and the first focal length was 22 mm, the second focal length was 110 mm, and the effective diameter was 80 m.
When a liquid crystal display element was irradiated with parallel light having an effective diameter of φ80 mm by using an elliptic mirror of m, the parallelism of the light was about ± 10 ° max.

That is, in the conventional type liquid crystal display device, the light source light that can be effectively used is such that the parallelism of irradiation light having a parallelism of about ± 10 ° max is at most ± 2.
Only the light up to 0 ° and ± 2.8 ° in the horizontal direction of the picture element was available, and the light with poorer parallelism could not be used.

Therefore, in the conventional liquid crystal display device,
To realize a brighter device, it is necessary to increase the brightness of the light source or improve the parallelism of light.

For example, when a bright light source is used to realize a brighter liquid crystal display device, the magnitude of the arc becomes large. Therefore, the parallelism of the light deteriorates, and the light that can be effectively used decreases. In addition, in order to improve the parallelism of light and increase the amount of light that can be effectively used,
When the size of the arc of the light source is reduced or the size of the illumination light incident on the liquid crystal display element is increased, the absolute light amount of the light source decreases in the former case and the light protruding from the liquid crystal display element increases in the latter case. . In other words, it is difficult to realize a brighter liquid crystal display device in the conventional method, and up to now, there has been no projection type color liquid crystal display device that solves the above problems.

The present invention has been made to solve the above-mentioned conventional problems, and increases the brightness of the light source, reduces the size of the light source, and reduces the diameter of the incident spot on each picture element of the liquid crystal display element. An object of the present invention is to obtain a projection type color liquid crystal display device capable of realizing brighter display without increasing parallelism due to increase.

[0022]

A projection type color liquid crystal display device according to the present invention (Claim 1) has incident wavelengths which are different from each other and are defined in a first plane corresponding to the respective wavelength ranges. A liquid crystal display element that performs light modulation processing for each light flux with respect to a plurality of light rays that enter at an angle, and each light flux that is provided on the light emission side of the liquid crystal display element and that passes through the liquid crystal display element is displayed on the display screen. And an optical system for projecting and synthesizing a color image. Further, the liquid crystal display device corresponds to a first light flux group generating means for generating a first projection light flux group including a plurality of light fluxes having different wavelength ranges, and each light flux in the first projection light flux group. And a second light flux group generating means for generating a second light flux group for projection composed of a plurality of light fluxes having the same wavelength range as that of each light flux, and the first and second light flux groups for projection. The optical axes of the two light beams of each set having the same wavelength range between them form a constant angle in the second plane different from the first plane, and the wavelength range of each wavelength range for the liquid crystal display element is And an optical unit for making the light beams incident on the liquid crystal display element such that the light beams have different incident angles defined in the first plane. Thereby, the above object is achieved.

According to a second aspect of the present invention, in the projection type color liquid crystal display device according to the first aspect, the liquid crystal display element is provided corresponding to each pixel for each color corresponding to each of the wavelength ranges. A plurality of color display electrodes for driving liquid crystals by receiving independent display signals for each color, and two light fluxes of each set having the same wavelength band between the first and second projection light flux groups, A microlens array for condensing light on a liquid crystal portion driven by a color display electrode having a color corresponding to a wavelength range is configured.

Hereinafter, the operation of the present invention will be described.

In the present invention (claim 1), for each of a plurality of light beams having different wavelength ranges, which are incident at an incident angle defined in the first plane corresponding to the respective wavelength ranges, Equipped with a liquid crystal display element that performs light modulation processing on
The optical axes of the first and second projection luminous flux groups of the two luminous fluxes in each set having the same wavelength range between them form a constant angle in a second plane different from the first plane. Moreover, the liquid crystal display element is made to enter the liquid crystal display element such that the incident angles of the light fluxes in the respective wavelength ranges with respect to the liquid crystal display element are different from each other defined in the first plane. Means that two projection light flux groups each having a light flux corresponding to a wavelength range required for color display are incident from different directions.

Therefore, the brightness of the light source is increased,
The amount of light of each color incident on each picture element can be increased without reducing the light source for improving the parallelism or increasing the diameter of the incident spot on each picture element of the liquid crystal display element. .

For example, light that is absorbed by a polarizing plate disposed on the incident surface side of the liquid crystal display element is formed with the transmitted light that passes through the polarizing plate at a constant angle with the optical axis of the transmitted light. The light can be incident on the liquid crystal display element from any direction. This makes it possible to effectively use the light that was conventionally wasted.

In the present invention (claim 2), two light fluxes of each set having the same wavelength band between the first and second projection light flux groups are formed on the picture element corresponding to the wavelength band. Since the positional relationship between the microlens array and the picture elements forming the liquid crystal display element is set so as to form the focused spot on the light source, all the light of the first and second projection light flux groups is It can be assigned to each picture element of the liquid crystal display element, and the light of the first and second projection light flux groups can be used without waste, and the amount of light transmitted through the liquid crystal display element can be increased.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In these figures, the same reference numerals indicate the same or corresponding parts.

(Embodiment 1) FIGS. 1 and 2 are views for explaining a single plate type liquid crystal display device according to a first embodiment of the present invention, and FIG. 1 (a) is the single plate type liquid crystal display device. 2A is a plan view schematically showing the structure, FIG. 1B is a rear view showing the structure of the apparatus viewed from the direction of the arrow Ib in FIG. 1A, and FIG.
FIG. 2 is a left side view showing the structure of the device as seen from the direction of arrow IIa in FIG.

In the drawings, the same reference numerals as those in FIGS. 7 to 9 designate the same parts as the conventional liquid crystal display device 200, and 101 is a single plate type using one liquid crystal display element 12 according to the first embodiment. In the projection type color liquid crystal display device, a white light source 1 has a metal halide lamp of 250 W and an arc length of 3.0 mm, and the light emitted from the light source 1 has its first focus at the position of the light source. The light is reflected by the spheroidal mirror 2 and is focused on the second focal point of the spheroidal mirror. Here, the spheroidal mirror 2 has a first focal length of 22 mm, a second focal length of 10 mm, and an effective diameter φ of 8 mm.
0 mm is used.

In the liquid crystal display device 101, the condenser lens 3 and the dichroic mirrors 4R, 4G,
4B, a polarization beam splitter 13 that transmits P-polarized light of the light source light (first projection light flux group) and reflects S-polarized light of the light source light is disposed. In the subsequent stage of 13, the S polarized light,
A mirror 14 is provided that reflects the transmitted P-polarized light at an angle of 2φ. Also, the mirror 1
A λ / 2 plate 15 for converting the S-polarized light reflected by the mirror 14 into P-polarized light (second projection light flux group) is disposed in the subsequent stage of 4. Here, the P-polarized light transmitted through the λ / 2 plate 15 and the P-polarized light transmitted through the polarization beam splitter 13 are respectively dichroic mirror 4 described above.
The light beams of respective colors are separated by R, 4G, and 4B and are incident on the liquid crystal display device 12.

Next, the operation will be described.

The light emitted from the white light source 1 is reflected by the spheroidal mirror 2 and condensed at the second focal point of the spheroidal mirror. At this time, the light condensed is made uniform in angular distribution by the integrator 11 arranged near the second focal point, and the diverged light is collimated by the condenser lens 3. The P-polarized light of the collimated light is transmitted through the polarization beam splitter 13, and the S-polarized light of the collimated light is in the vertical plane (the arrival direction of the S-polarized light and the liquid crystal display element). Is reflected in a predetermined direction (in a plane including the vertical direction of the display surface). Then, the reflected S-polarized light is reflected by the mirror 14 in a direction forming an angle difference 2φ with respect to the P-polarized light (first P-polarized light) within the vertical plane, and the λ / 2 plate 15 is reflected. Through P
It is converted into polarized light (second P-polarized light).

Next, the red, green and blue lights of these first and second P-polarized lights are dichroic mirrors 4R and 4R.
G, 4B are selectively reflected so that each has a predetermined reflection angle in a horizontal plane (a plane including the horizontal direction of the display surface of the liquid crystal display element and perpendicular to the vertical plane).
It is separated into three light fluxes of red, green, and blue.

As a result, light of the same color is incident on the liquid crystal display element 12 from the two directions with an angle difference φ in the vertical plane, and light of three colors is incident on the liquid crystal display element 12 from the three directions with an angle difference θ in the horizontal plane. Light beams of the respective directions enter the picture elements of the corresponding color in the liquid crystal display element 12 from the respective directions. The light transmitted through each picture element is projected on the screen 7 through the polarizing plate 9, the field lens 5, and the projection lens 6 to display a color image.

More specifically, the light condensed by the spheroidal mirror 2 is made uniform in the angular distribution of light by an integrator 11 arranged near the second focal point, and the diverged light is a condenser lens. Parallelized at 3. The collimated light is split by the polarization beam splitter 13 into P-polarized light and S-polarized light. That is, the P-polarized light is transmitted through the polarization beam splitter 13, and the S-polarized light is reflected by the polarization beam splitter 13 in the direction perpendicular to the paper surface of FIG. 1A (see FIG. 2A).

The S-polarized light reflected by the polarization beam splitter 13 is reflected by the mirror 14 so as to form an angle difference 2φ with respect to the P-polarized light (first P-polarized light) transmitted through the polarization beam splitter 13. And further λ
The / 2 plate 15 converts the light into P-polarized light (second polarized light).

Next, these first and second polarized lights are
The dichroic mirrors 4R, 4G, and 4B that selectively reflect red, blue, and green light separate the three primary colors of red, blue, and green. At this time, the dichroic mirror separates the lights such that the red and blue lights form a predetermined angle θ with respect to the green light.

As a result, in each picture element of the liquid crystal display element 12, two directions forming an angle difference φ with the direction perpendicular to the light incident surface of the liquid crystal display element are formed in a plane parallel to the paper surface of FIG. 1B. Therefore, the light of the same color of the first and second P-polarized light is incident. Also,
Light of different colors of the first and second P-polarized light is shown in FIG.
In the plane parallel to the paper surface of the liquid crystal display element, light enters the liquid crystal display element from three directions, that is, a direction perpendicular to the light incident surface of the liquid crystal display element and two directions forming an angle difference θ with the light incident surface, and then enters the corresponding color picture element. Will be done. That is, light from a total of six directions is incident on the liquid crystal display element 12.

The liquid crystal display element 12 has the same structure as the conventional one, and the microlens array 10 is used.
And a liquid crystal display panel 20. In the liquid crystal display panel 20, one picture element has a picture element electrode 2 as shown in FIG.
1, a thin film transistor (TFT) 22 for driving this,
The storage capacitor 23 and the like are included. Further, the light shielding film 28 formed on the counter substrate is provided with an opening portion (picture element opening portion) 32 which is aligned with the picture element electrode 21.

Here, the incident angles of the respective colors with respect to the individual microlenses 10a are as shown in FIG.
As shown in FIG. 3A, the red light flux and the blue light flux form θ with respect to the green light flux, respectively, and FIG.
As shown in, the light fluxes of different colors having different incident directions form an angle φ with respect to the lens optical axis, and the condensed spots of the respective colors are set to be incident on different picture element openings. . For convenience of explanation, FIG. 3 shows only the principal rays of the luminous flux, and FIG. 3B shows only the principal ray of the green luminous flux.

The microlens array 10 is, for example, a hexagonal microlens 10a in which the outer peripheral portions of spherical lenses are fused with each other by a plurality of ion exchange methods. The relative positional relationship of is as shown in FIG.

Specifically, in the liquid crystal display panel 20, the picture elements corresponding to the respective colors are repeatedly arranged in the order of red, green and blue for each horizontal line of the display screen, and each picture element is It is located so as to face the opening portion (picture element opening portion) 32 of the light shielding film 28. That is, the arrangement of the picture element openings 32 is such that square blocks are arranged vertically and horizontally with each row being laterally displaced by half the width dimension thereof.
The individual prism-shaped microlenses are arranged so that the center of the lens optical axis is on the center of the boundary line between the blue and red picture elements. However, in addition to this arrangement, the lens optical axis center should be on the center of the boundary line between the red and green picture elements, or the lens optical axis center should be on the center of the boundary line between the green and blue picture elements. May be.

Then, the first and second P-polarized light that is incident light on the liquid crystal display element 12 is transmitted through the (P-polarized light transmission type) polarizing plate 8, and the green light flux thereof is included in the microlens array 10.
From the direction tilted up and down by φ in the vertical plane with respect to the optical axis of
In the horizontal plane, the light is incident without inclination and forms a spot in the green pixel. The red and blue luminous fluxes are arranged on the left and right sides of the green picture element from the direction inclined at an angle θ to the left and right with respect to the green luminous flux in the horizontal plane, and from the direction inclined at an angle φ up and down in the vertical plane, It is incident on the red or blue picture element to form a spot. Strictly speaking, the green light fluxes of the first and second P-polarized light rays condensed by the individual microlenses 10a form focused spots on the green picture elements corresponding to the respective microlenses 10a. To do. Concerning the blue and red light fluxes of the first and second P-polarized light, similarly to the green light flux, focused spots are formed on the blue and red picture elements corresponding to the respective microlenses 10a.

The light transmitted through each picture element in this way is polarized temporary 9.
A color image is displayed by being projected on the screen 7 through the field lens 5 and the projection lens 6.

Next, a method of setting the angles 2φ and θ will be described.

For example, the picture element pitch is 100 μm both vertically and horizontally.
m, the size of the pixel opening is 50 μm in length, 70 μm in width, and the number of pixels is 450 in length and 600 in width, the focal length of the microlens array is 1.1 mm (n = 1.53) (distance in air = 1.1 mm / 1.53 = 0.72 mm), in the horizontal plane including the optical axis of the microlens (FIG. 3A).
), The permissible amount of parallelism of light incident on the opening of the green pixel is ± tan ⁻¹ (35/720) = ± 2.8.
It becomes ゜.

Next, with respect to the light incident on the opening portion of the red or blue picture element, the direction of the principal ray of the parallel light flux is the direction of the parallel light speed principal ray of the light incident on the opening portion of the green picture element. With respect to θ = ± tan ⁻¹ (100/720) = ± 8 °, the allowable incident angle of light is ± (tan ⁻¹ ((100 + 35) / 720) to tan ^−1.
((100-35) / 720)) = ± (10.6 ° ~
5.2 °). In other words, the allowable amount of parallelism of light with respect to a light beam in which the principal ray is inclined by θ = ± 8 ° with respect to the optical axis of the microlens in the horizontal plane is ± (2.6 ° to (-2.8 °)). Becomes

Next, within the vertical plane including the optical axis of the microlens (see FIG. 3B), light incident on the green, blue, or red picture element from two directions symmetrical with respect to the optical axis. Is
The direction of the principal ray of the parallel luminous flux is φ = ± tan ⁻¹ (100/720) = ± 8 with respect to the optical axis of the microlens.
The angle of incidence is ± (tan ^-1 ((100 + 25) / 720) to tan ^-1 ).
((100-25) / 720)) = ± (9.8 ° -5.
9 °). In other words, the allowable amount of parallelism of light with respect to a light beam in which the principal ray is inclined by φ = ± 8 ° with respect to the optical axis of the microlens in the vertical plane is ± (1.8 ° to (-
2.1 °)).

Therefore, in the first embodiment, for example,
The first P-polarized light transmitted through the polarization beam splitter 13 is taken into the corresponding picture element of the liquid crystal display element 12 from the direction inclined by φ = 8 ° with respect to the lens optical axis within the vertical plane, and the conventional waste is further reduced. The S-polarized light, which has become, is also converted into the second P-polarized light, and is φ with respect to the lens optical axis within the vertical plane.
The same amount is taken into the corresponding picture element of the liquid crystal display element from the direction inclined by -8 °. Therefore, the brightness of the display is improved to about twice that of the conventional one.

Further, unlike the conventional case, since the S-polarized light is not blocked and absorbed by the polarizing plate and is not replaced with heat, the polarizing plate is not melted or burned.

(Embodiment 2) FIG. 4 is a schematic diagram for explaining a single plate type liquid crystal display device according to Embodiment 2 of the present invention. FIG. 4 (a) is a plan view of the device. 4B is a view of the apparatus viewed from the direction of arrow IVb in FIG. 4A (rear view), and FIG. 4C is a view of the apparatus viewed from the direction of arrow IVc in FIG. 4A ( (Left side view).

In the figure, the same reference numerals as those in FIGS. 1 to 3 designate the same elements as those in the first embodiment, and 102 is a single-plate type liquid crystal display device according to the second embodiment. It has white light sources 1, 1 '. Here, as each of the light sources, a metal halide lamp of 250 W and an arc length of 3.0 mm is used. In addition, for each light source 1, 1 ′, the paraboloidal mirror 2 a that rotates so that the focal point matches the position of each light source,
2a 'is arranged. These rotating parabolic mirrors 2a,
2a 'has a focal length of 22 mm and an effective diameter φ of 80 m.
It has become m.

The first and second lights emitted from the light sources 1 and 1'are reflected by the rotating parabolic mirrors 2a and 2a 'and collimated. At this time, the chief rays of the collimated light sources form the same angle 2φ as in the first embodiment in the vertical plane (the plane including the direction of the incoming light and the direction perpendicular to the display surface of the liquid crystal display element). It is like this.

These lights are dichroic mirrors 4R, 4G and 4 which selectively reflect red, blue and green lights, respectively.
B separates the three primary colors of red, blue, and green. The red and blue lights separated at this time form an angle θ with respect to the green light in a horizontal plane (a plane perpendicular to the vertical direction of the display surface of the liquid crystal display element).

As a result, the same color of first and second light is incident on each picture element of the liquid crystal display element 12 from two directions forming an angle difference φ with the lens optical axis in the vertical plane. . Also,
Light of different colors of the first light and the second light is incident on the liquid crystal display element from three directions, that is, the lens optical axis direction in the horizontal plane and two directions forming an angle difference θ with the lens optical axis direction, and the light of the corresponding color is displayed on the picture element of the corresponding color. It will be incident. That is, light from a total of six directions is incident on each picture element in the liquid crystal display element 12 corresponding to each color.

Also in the second embodiment, the incident angle of the light of each color on each microlens 10a is set so that the condensed spot of the light flux of each color is incident only on the pixel opening of the corresponding color. There is.

The relative positional relationship between the picture element array and the microlenses in the liquid crystal display element is as shown in FIG. 2 as in the first embodiment.

As a result, the S-polarized light of the incident light (first and second light) that has reached the liquid crystal display element 12 is absorbed by the P-polarized transmission type polarizing plate 8 and only the P-polarized light is transmitted. . At this time, the green light is incident on the liquid crystal display panel 20 from two directions which are inclined vertically by an angle φ with respect to the lens optical axis in the vertical plane and without being inclined with respect to the lens optical axis in the horizontal plane.
A spot is formed in the green picture element. Further, the red and blue lights are tilted with respect to the green light in the horizontal plane by an angle θ with respect to the lens optical axis, and in the vertical plane with respect to the lens light axis by a vertical angle φ. The light enters the liquid crystal display panel from two different directions, and spots are formed only in the picture elements of the corresponding colors of red and blue, which are arranged on the left and right of the green picture element.

The light transmitted through each pixel in this way is polarized by the polarizing plate 9,
A color image is displayed by being projected on the screen 7 via the field lens 5 and the projection lens 6.

Therefore, in the second embodiment, the light flux from one light source 1 is taken into the corresponding picture element of the liquid crystal display element from the direction inclined by the angle φ with respect to the lens optical axis in the vertical plane, for example. Further, the same amount of light flux from another light source 1'is taken into the corresponding picture element of the liquid crystal display element from the direction inclined by the angle (-φ) with respect to the lens optical axis. Therefore, the brightness of the display is improved to about twice that of the conventional one.

In this embodiment, the light source is 250 W,
An arc length of 3.0 mm was used, but when using two light sources like this, for example, one light source is 125 W,
An arc having a short arc length, such as an arc length of 1.5 mm, whose output is suppressed is used. For example, the rotating parabolic mirrors 2a, 2a '
It is also possible to reduce the light beam diameter while keeping the parallelism of the parallel light incident on the liquid crystal optical element as it is by making the focal length thereof smaller than 11 mm and the effective diameter φ40 mm. As a result, other optical elements such as lenses are made smaller, the apparatus is made smaller, and the cost is reduced.

(Third Embodiment) FIG. 5 is a left side view for explaining a single plate type liquid crystal display device according to a third embodiment of the present invention.

In the figure, 103 is the liquid crystal display device of the third embodiment, which has a white light source 1 having a metal halide lamp of 250 W and an arc length of 3.0 mm. A rotary parabolic mirror 2a is provided for the white light source 1 so that the focal point coincides with the position of the light source. The rotating parabolic mirror 2a
Has a focal length of 22 mm and an effective diameter of φ80 x 160 mm.
It has become. That is, the rotary parabolic mirror 2a has a rectangular opening, and its effective length and width are 80 × 160 mm.
It has become. Further, a wedge prism 16 is arranged on the parallel light emitting side of the rotating parabolic mirror 2a, and the prism 16 allows the parallel light from the rotating parabolic mirror 2a to travel within the vertical plane. It is adapted to be converted into two light beams (first and second light beams) whose axes form an angle 2φ.

Next, the function and effect will be described.

The light emitted from the light source 1 is reflected by the rotating parabolic mirror 2a and collimated. Then, the collimated light passes through the wedge prism 16,
The chief ray m of the reflected light (first light flux) from the parabolic mirror 2a ₁ on the left side of the paper in FIG. 5 and the parabolic mirror 2a ₂ on the right side of the paper in FIG.
The principal ray m ′ of the reflected light (second light flux) from is having the same angular difference 2φ as the two rays directed to the dichroic mirror in the first embodiment.

In the horizontal plane, these lights are converted into three lights of three primary colors of red, blue and green by dichroic mirrors 4R, 4G and 4B which selectively reflect red, blue and green lights, respectively. To be separated. This separation of the light is performed so that the red and blue lights make an angle θ with the green light.

As a result, light of the same color enters the liquid crystal display panel from the two directions with an angle difference φ in the vertical plane, and light of three colors enters the liquid crystal display panel from the three directions with an angle difference θ in the horizontal plane. Light from a total of six directions that has entered the panel enters each picture element in a liquid crystal display element (not shown) corresponding to each color.

At this time, the incident angle of each color with respect to each microlens is set so that the condensed spot of the light flux of each color is incident only on the pixel opening of the corresponding color.

Further, the relative positional relationship between the picture element array and the microlens array in the liquid crystal display element is as shown in FIG. 2B as in the first embodiment.

As a result, of the incident light that has reached the liquid crystal display element 12, the S-polarized light is absorbed by the P-polarized transmission type polarizing plate 8, and only the P-polarized light is transmitted. At this time, the green light is incident on the liquid crystal display element from two directions that are tilted up and down with respect to the lens optical axis in the vertical plane by an angle φ with respect to the lens optical axis in the horizontal plane. A focused spot is formed inside. In addition, the red light and the blue light respectively form an angle θ with respect to the lens light axis in the horizontal plane with respect to the green light.
From the tilted direction, the liquid crystal panel is incident from two directions which are tilted up and down by an angle φ with respect to the lens optical axis in the vertical plane, and the corresponding colors of red and blue are arranged on the left and right of the green picture element. Form spots only within the picture element.

The light transmitted through each picture element in this way is polarized by the polarizing plate 9,
A color image is displayed by being projected on the screen 7 via the field lens 5 and the projection lens 6.

Therefore, also in the third embodiment, the reflected light beam from the left side portion of the rotary parabolic mirror 2a corresponds to the liquid crystal display element from the direction inclined by the angle φ with respect to the lens optical axis in the vertical plane, for example. The light flux reflected from the right side portion of the rotary parabolic mirror 2a is further captured in the corresponding picture element of the liquid crystal display element from a direction inclined at an angle (−φ) with respect to the lens optical axis. It is taken in as much as that of. Therefore, the brightness of the display is improved to about twice that of the conventional one.

Further, in the third embodiment, the optical system is simpler and the required optical elements are smaller than those in the other first and second embodiments, so that the effect of downsizing the apparatus and reducing the cost is great.

In the third embodiment, a wedge prism is used to obtain two parallel rays whose optical axes form an angle of 2φ. However, the method of obtaining such two rays is not limited to this. It is not limited.

As another method, for example, the rotating parabolic mirror 2a shown in FIG. 5 is rotated clockwise about the light source 1 by a constant angle and the same is rotated in the opposite direction by the same angle. As shown in FIG. 6, a main ray m of the reflected light from the parabolic mirror portion 2b ₁ on the left half of the rotation parabolic mirror 2b and the parabolic mirror portion 2b on the right half of the rotation parabolic mirror 2b as shown in FIG. The angle difference between the principal ray m ′ of the reflected light from ₂ is 2φ.
You may make it.

A rotating parabolic mirror 2b having a shape as shown in FIG.
By using, it is possible to obtain two parallel lights whose optical axes form an angle 2φ without increasing the number of optical elements such as wedge prisms, which is preferable because the cost of the apparatus can be further reduced.

[0079]

As described above, according to the liquid crystal display device of the present invention (Claim 1), the liquid crystal display devices have different wavelength ranges.
The first and second projections are provided with a liquid crystal display element that performs light modulation processing on each of a plurality of light beams that are incident at an incident angle defined in the first plane corresponding to each wavelength range. The luminous flux groups for use in the liquid crystal display element are arranged such that the optical axes of the two luminous fluxes of each set having the same wavelength range between them form a constant angle in the second plane different from the first plane. Since the light beams in the wavelength range are made incident on the liquid crystal display element so that the incident angles are different from each other defined in the first plane, the liquid crystal display elements are required to perform color display. Two projection light flux groups having light fluxes corresponding to the wavelength range are incident from different directions, and therefore,
Without increasing the brightness of the light source, reducing the light source for improving the parallelism, or increasing the diameter of the incident spot on each pixel of the liquid crystal display element, The amount of light can be increased.

For example, light absorbed by a polarizing plate disposed on the incident surface side of the liquid crystal display element forms a constant angle with the optical axis of the transmitted light together with the transmitted light that passes through the polarizing plate. The light can be incident on the liquid crystal display element from any direction. As described above, according to the present invention, since the light from the light source can be used without waste, there is an effect that the display image becomes very bright as compared with the conventional one.

According to the present invention (claim 2), in the liquid crystal display element, two light fluxes of each set having the same wavelength band between the first and second projection light flux groups are:
Since the positional relationship between the microlens array and the picture elements forming the liquid crystal display element is set so as to form the focused spot on the picture element corresponding to the wavelength range, the first and second projections are performed. All the light of the luminous flux group for light can be assigned to each picture element of the liquid crystal display element, and the light of the first and second luminous flux groups for projection can be used without waste and transmitted through the liquid crystal display element. You can increase the amount of light. As a result, a highly efficient and bright liquid crystal display device can be realized.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a projection type color liquid crystal display device according to a first embodiment of the present invention, FIG. 1 (a) is a plan view schematically showing the configuration of the liquid crystal display device, and FIG. FIG. 2B is a rear view showing the structure of the device as seen from the direction of arrow Ib in FIG.

2 is a diagram for explaining the projection type color liquid crystal display device according to the first embodiment, and FIG. 2 (a) is a view of the liquid crystal display device as seen from a direction of an arrow IIa in FIG. 1 (a). FIG. 2B is a left side view showing the structure, and FIG. 2B is a view showing the positional relationship between the picture elements and the microlens array in the liquid crystal display element.

3A is a diagram showing a structure of a liquid crystal display element in the liquid crystal display device according to the first embodiment in a horizontal plane and a path of an incident light beam, and FIG. 3B is the liquid crystal display element. It is a figure which shows the structure in the vertical plane of, and the path of an incident light beam.

FIG. 4 is a diagram for explaining a projection type color liquid crystal display device according to a second embodiment of the present invention, FIG. 4 (a) is a plan view schematically showing the configuration of the liquid crystal display device, and FIG. 4B is a rear view showing the structure of the device as seen from the direction of arrow IVb in FIG. 4A, and a left side view showing the structure as seen from the direction of arrow IVc of FIG. 4C.

FIG. 5 is a left side view for explaining a projection type color liquid crystal display device according to a third embodiment of the present invention.

FIG. 6 is a left side view for explaining a projection type color liquid crystal display device according to a modification of the third embodiment of the present invention.

FIG. 7 is a plan view showing a conventional projection type color liquid crystal display device.

FIG. 8 is an enlarged cross-sectional view showing an enlarged structure of a liquid crystal display element that constitutes a conventional liquid crystal display device.

FIG. 9 is a view showing a structure of a liquid crystal display element in a conventional liquid crystal display device in a horizontal plane.

FIG. 10 is a diagram for explaining a positional relationship between a picture element of a liquid crystal display element and a microlens array in a conventional liquid crystal display device.

[Explanation of symbols]

1, 1'Light source 2 Rotating ellipsoidal mirror 2a, 2a ', 2b Rotating parabolic mirror 2a ₁ , 2a ₂ , 2b ₁ , 2b ₂ Parabolic mirror part 3 Condenser lens 4R, 4G, 4B Dichroic mirror 5 Field lens 6 Projection Lens 7 Screen 8, 9 Polarizing Plate 10 Microlens Array 10a Microlens 11 Integrator 12 Liquid Crystal Display Device 13 Polarizing Beam Splitter 14 Total Reflection Mirror 15 λ / 2 Plate 16 Wedge Prism 20 Liquid Crystal Panel 21 Picture Element Electrode 22 Thin Film Transistor 23 Auxiliary Capacitance 24 Signal line 25 Gate line 26 Counter substrate 27 Counter electrode 28 Light shielding layer 30 Liquid crystal layer 32 Picture element opening 33 Glass substrate 101, 102, 103 Projection color liquid crystal display device

Claims (2)

[Claims] 1. A liquid crystal display for subjecting a plurality of light fluxes having different wavelength ranges, which are incident at an incident angle defined in a first plane corresponding to the respective wavelength ranges, to each light flux. An element, an optical system provided on the light emission side of the liquid crystal display element, for projecting each light flux transmitted through the liquid crystal display element onto a display screen to synthesize a color image, and a plurality of optical systems having different wavelength ranges from each other. A first light flux group generating means for generating a first projection light flux group composed of a light flux, and a wavelength range corresponding to each light flux in the first projection light flux group, and having the same wavelength range as that of each light flux. A second light flux group generating means for generating a second projection light flux group composed of a plurality of light fluxes, and a first light flux group for projection and a second light flux group for projection, each of which has a same wavelength range between them. The optical axes of the two light beams form a constant angle in a second plane different from the first plane. And a projection type optical device that makes the liquid crystal display element incident on the liquid crystal display element so that the incident angles of the light fluxes in the respective wavelength ranges with respect to each other are different from each other defined in the first plane. Color liquid crystal display device. 2. The projection type color liquid crystal display device according to claim 1, wherein the liquid crystal display element is provided corresponding to each pixel for each color corresponding to each wavelength range, and an independent display signal for each color. And a plurality of color display electrodes for driving the liquid crystal, and two light fluxes of each set having the same wavelength band between the first and second projection light flux groups of the color corresponding to the wavelength band. A projection type color liquid crystal display device comprising: a microlens array that transmits light to a liquid crystal part driven by a color display electrode.