JP2893083B2 - Projection type liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type liquid crystal display device.

[0002]

2. Description of the Related Art Recently, as a liquid crystal display device for displaying a television image or the like using a liquid crystal panel, light from a light source is made incident on the liquid crystal panel, and light emitted from the liquid crystal panel is projected on a screen to form an image. Projection type liquid crystal display devices for displaying images have been developed.

There are two types of projection type liquid crystal display devices: one for projecting light emitted from a liquid crystal panel onto a screen through a linear projection optical path, and one for projecting light emitted from a liquid crystal panel onto a screen with a bent projection optical path. The projection type liquid crystal display device includes a projection mirror that reflects projection light from the liquid crystal panel in a predetermined direction to form a bent projection optical path.

[0004]

However, in a projection type liquid crystal display device in which a projection optical path from a liquid crystal panel to a screen is a bent optical path having a projection mirror, light for forming an image to be displayed on a screen is reflected by the projection mirror. When the light is reflected by the light source, the light intensity is attenuated and the light intensity is reduced, so that the image displayed on the screen is darkened.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a projection optical path from a liquid crystal panel to a screen using a bent optical path having a projection mirror. Another object of the present invention is to provide a projection-type liquid crystal display device that can project a light forming an image displayed on a screen onto a screen with almost no attenuation and display a bright image.

[0006]

According to the present invention, in order to achieve the above object, light from a light source is incident on a liquid crystal panel.
The light emitted from the liquid crystal panel is converted into a light having a projection mirror.
Image projected on lenticular screen through curved light path
In the projection type liquid crystal display device, the inclination direction of the projection mirror forming the refraction optical path is changed by the lenticular.
While arranged to substantially perpendicular to the vibration direction of the light forming the image displayed on over the screen, the
Adjust the length direction of the lens part of the lenticular screen
Characterized in that the direction is almost perpendicular to the direction of light oscillation.
Things.

[0007]

According to the above construction, the projection
Image light is reflected at a higher reflectance by the
The image light reaching the lean is not attenuated, and
The image light is transmitted through the
Image light emitted from the screen without attenuation
You.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows an overall configuration of a projection type liquid crystal display device, and FIG. 2 shows a projection unit therein.
The projection type liquid crystal display device of this embodiment is provided with a transmission type screen on the front surface of the device, and projects light transmitted through a liquid crystal panel provided inside the device onto the transmission type screen from the back side, and this screen This is a rear projection type in which an image displayed by the projected light is observed from the front side of the apparatus.

The projection type liquid crystal display device of this embodiment has three liquid crystal panels. The first liquid crystal panel has a red image, the second liquid crystal panel has a green image, and the third liquid crystal panel has a third liquid crystal panel. A blue image is displayed on the screen, and the red, green, and blue lights emitted from the respective liquid crystal panels are projected on a screen to display a full-color image.

In FIGS. 1 and 2, reference numeral 1 denotes a case of a projection type liquid crystal display device, and a display window opened on the front surface of the case 1 has a large number of stripe-shaped micro-width lens portions in parallel on its surface. A transmissive screen 2 having a lined lenticular lens 3 is provided.

Reference numeral 4 denotes a projection unit provided in the case 1, 5 and 6 denote two projection mirrors constituting a refracted projection optical path, and the projection light (full color image light) from the projection unit 4 is the first projection mirror. The light is reflected by the projection mirror 5 toward the second projection mirror 6.
Is reflected toward the screen 2.

The structure of the projection unit 4 will be described.
In FIG. 2, 7R, 7G, and 7B are three liquid crystal panels. Each of the liquid crystal panels 7R, 7G, and 7B has the same pixel arrangement and the same liquid crystal orientation direction. These liquid crystal panels 7R, 7G, 7B are of the TN (twisted nematic) type, and an incident light polarizing plate 8 is provided on a light incident surface thereof, and an image forming polarizing plate 9 is provided on a light emitting surface thereof. The liquid crystal therein is twist-aligned with respect to the polarization axis direction of the incident light polarizing plate 8.

Among these liquid crystal panels, 7R is a liquid crystal panel for displaying a red image for displaying a red image, 7G is a liquid crystal panel for displaying a green image for displaying a green image, and 7G.
B is a blue image display liquid crystal panel for displaying a blue image, and these liquid crystal panels 7R, 7G, 7B
Are to display images of the same color components of red, green, and blue, respectively.

One of the liquid crystal panels 7R, 7G, 7B, for example, a green image display liquid crystal panel 7G, is disposed so that its light exit surface faces the projection lens 10, and the other two liquid crystal panels. The panel, that is, the red image display liquid crystal panel 7R and the blue image display liquid crystal panel 7B
Light emitting surfaces are arranged on both sides of an image synthesizing dichroic prism 11 arranged between the green image display liquid crystal panel 7G and the projection lens 10, and the respective liquid crystal panels 7R, 7G, 7B are further arranged. Respectively
They are arranged at the same distance from the center of the dichroic prism 11.

Reference numeral 12 denotes each of the liquid crystal panels 7R, 7G, 7B.
The light source 12 is provided for each liquid crystal panel 7.
It is provided to face the green image display liquid crystal panel 7G facing the projection lens 10 among R, 7G, and 7B. The light source 12 includes a light source lamp, and a parabolic mirror reflector that reflects light emitted from the light source lamp as parallel light toward the green image display liquid crystal panel 7G.

The reference numerals 16a and 16b denote light for separating light (white light) from the light source 12 into three primary colors of red, green and blue.
The first dichroic mirror 16a is used for separating blue light. The dichroic mirror 16a for separating blue light is illuminated from the light source 12 between the light source 12 and the liquid crystal panel 7G for displaying a green image. It is arranged to be inclined at an angle of 45 ° with respect to the optical axis of light (hereinafter referred to as a light source optical axis) O ₀ .

This blue light separating dichroic mirror 1
Reference numeral 6a denotes a blue light separating dichroic mirror 16a of the light from the light source 12, which transmits blue component wavelength light and reflects other wavelength light, that is, red and green component wavelength light.
The blue light B transmitted through a, the blue light B transmitted through the light-source optical axis O ₀ (blue light separating dichroic mirror 16a between the blue light separating dichroic mirror 16a and the green image display liquid crystal panel 7G Dichroic mirror 16a for separating blue light at an angle of 45 ° with respect to the optical axis)
And a blue light reflecting first electrode disposed at an angle of 90 °.
It is reflected in a direction orthogonal to the light source optical axis O ₀ by the mirror 17a.

Further, beside the first mirror 17a,
A blue light reflecting second mirror 17b is arranged in parallel with the first mirror 17a, and the blue light B reflected by the first mirror 17a is parallel to the light source optical axis O ₀ by the second mirror 17b. Blue light reflecting liquid crystal panel 7B, which is reflected at an angle of 45 ° and faces the second mirror 17b at an angle of 90 °. The light is reflected by the third mirror 17c toward the blue image display liquid crystal panel 7B.

On the other hand, the red-green light RG reflected by the blue light separating dichroic mirror 16a is directed to a side opposite to the side on which the blue light reflecting second and third mirrors 17b and 17c are arranged, and to a blue light separating light RG. The blue light B reflected by the light source optical axis O ₀ and the blue light reflecting second mirror 17b is reflected by a red-green light reflecting mirror 18 provided in parallel to the blue light separating dichroic mirror 16a so as to face the dichroic mirror 16a. Is reflected in a direction parallel to the optical axis O _{1 of the} red-green light reflecting mirror 1 at an angle of 45 ° with respect to this optical axis.
Then, the light enters a second dichroic mirror 16b which is disposed so as to face 90 at an angle of 90 °.

The second dichroic mirror 16b
Divides the red-green light RG reflected by the blue light separating dichroic mirror 16a into red light R and green light G. The red-green light separating dichroic mirror 16b
Is designed to transmit red component wavelength light and reflect other wavelength light, that is, green component wavelength light.

The red light R transmitted through the red-green light separating dichroic mirror 16b is opposed to the light incident surface of the red image display liquid crystal panel 7R at an inclination angle of 45 ° and the red-green light separating dichroic mirror 16b. Dichroic mirror 16
The light is reflected toward the red image display liquid crystal panel 7R by a red light reflection mirror 19 arranged in parallel with and opposed to b.

The green light G reflected by the red-green light separating dichroic mirror 16b is opposed to the light incident surface of the green image display liquid crystal panel 7G at an inclination angle of 45 ° and the red-green light separating dichroic mirror. The light is reflected toward the green image display liquid crystal panel 7G by the green light reflection mirror 20 disposed in parallel with and opposed to 16b.

In this embodiment, the green light reflecting mirror 20 is arranged back to back with the first blue light reflecting mirror 17a. However, the green light reflecting mirror 20 and the first blue light reflecting mirror 17a are arranged. May be a single mirror having both surfaces as reflection surfaces, or when these two mirrors are separated, they may be arranged apart from each other. In this embodiment, the mirrors 17a, 17b, 17c, 18,
The mirrors 19 and 20 are increased reflection mirrors whose reflection surfaces are provided with a reflection coating, or are dichroic mirrors, and each of the mirrors 17a, 17b, 17c, 18,
If 19 and 20 are increased reflection mirrors, the light reflectance can be increased.

Each of the mirrors 17a, 17b, 17c,
When the dichroic mirrors 18, 19 and 20 are used, each mirror may reflect the color light incident on the mirror with its wavelength band narrowed slightly, and transmit the light of the remaining wavelength band. If each mirror is a dichroic mirror as described above, each of the liquid crystal panels 7R, 7G,
The red, green, and blue lights incident on 7B can be made closer to the primary colors. When both the green light reflecting mirror 20 and the blue light reflecting first mirror 17a arranged back to back are dichroic mirrors, the two mirrors 2 are used.
It is necessary to provide a light-absorbing layer for absorbing transmitted light on the back of 0 and 17a (between the mirrors when both mirrors 20 and 17a are superposed).

The green light reflecting mirror 20 and the red-green light separating dichroic mirror 16b are connected to the optical axis O _{3 of the} green light G reflected by the green light reflecting mirror 20 toward the green image display liquid crystal panel 7G. Are arranged so as to coincide with the light source optical axis O ₀ , and the blue light reflecting second and third mirrors 17 b and 17 c, the red-green light reflecting mirror 18 and the red-green light separating dichroic mirror 1 are further arranged.
6b and a red light reflecting mirrors 19, the green light G reflected by the optical axis O ₁ and the green light reflection mirror 20 is reflected by the second mirror 17b for blue light reflected blue light B and the optical axis O ₃ the spacing a _1, distance a ₂ and the a and the optical axis O ₃ of the green light G reflected by the optical axis O ₂ and green light reflecting mirror 20 of the red light R transmitted through the red green light separating dichroic mirror 16b ₁ =
As the A _2, it is arranged at equal distances from the light source optical axis O _0.

The red light reflecting mirror 19 and the third blue light reflecting mirror 17c are
The optical axes of the red light R and the blue light B that are reflected by c and pass through the red image display liquid crystal panel 7R and the blue image display liquid crystal panel 7B and enter the image synthesizing dichroic prism 11 have a green light reflection mirror 20. The optical axis O of the green light G reflected by the light and transmitted through the green image display liquid crystal panel 7G and incident on the image synthesizing dichroic prism 11
₃ and the center of the dichroic prism 11.

Then, each of the liquid crystal panels 7R, 7G, 7B
Are arranged at the same distance from the center of the dichroic prism 11 as described above, and the light paths of the red, green and blue lights R, G and B are light paths which are bent at right angles. To red image display liquid crystal panel 7R
The light path length of the red light R, the light path length of the green light G from the light source 12 to the liquid crystal panel 7G for displaying a green image, and the light source 12
And the optical path length of the blue light B from the liquid crystal panel 7B to the blue image display liquid crystal panel 7B are all equal.

As described above, each of the liquid crystal panels 7
The reason why the optical path lengths to R, 7G, and 7B are equal is that the intensities of red, green, and blue light incident on the liquid crystal panels 7R, 7G, and 7B are equalized.

That is, if the light from the light source 12 is perfectly parallel light, the intensities of the red, green, and blue light incident on each of the liquid crystal panels 7R, 7G, 7B are determined by the dichroic mirrors 16a and 16b. In fact, even if the reflector of the light source 12 is a parabolic mirror reflector, the light from the light source 12 is not completely parallel light but light that travels while spreading to some extent. The longer the optical path from 12, the larger the light beam spreads.

For this reason, the liquid crystal panel 7 from the light source 12
If there is a difference in the optical path lengths to R, 7G, and 7B, the optical path length from the light source 12 is smaller than the spread of the luminous flux of the green light G incident on the green image display liquid crystal panel 7G having the shorter optical path length from the light source 12. The spread of the luminous flux of the red light R and the blue light G incident on the red image display liquid crystal panel 7R and the blue image display liquid crystal panel 7B, which are long, becomes large. Therefore, the red image display liquid crystal panel 7R and the blue image display The illuminance per unit area of the light incident on the liquid crystal panel 7B is reduced, and the intensity of the light incident on the red image display liquid crystal panel 7R and the blue image display liquid crystal panel 7B is reduced.

Therefore, in this embodiment, as described above, the optical path lengths from the light source 12 to the liquid crystal panels 7R, 7G, 7B are equal, and if the optical path lengths are equal, the liquid crystal panels 7R, 7G, 7B are equal. Since the spread of the red, green, and blue light beams incident on the liquid crystal panel are all equal, each liquid crystal panel 7
Light of equal intensity can be incident on R, 7G, and 7B.

Further, the dichroic mirror 13a,
13b and light reflecting mirrors 17a, 17b, 17c, 1
8, 19 and 20 all have a polarizing action,
The transmittance and reflectance of the light incident on the dichroic mirrors 13a and 13b differ depending on the vibration direction of the light.
Also, the light reflecting mirrors 17a, 17b, 17c, 18, 1
The reflectance of the light incident on the light sources 9 and 20 also differs depending on the vibration direction of the light.

That is, of the light transmitted through the dichroic mirror, the light vibrates in a direction perpendicular to the optical axis on a plane perpendicular to the dichroic mirror surface and along the direction of inclination of the dichroic mirror (plane along the plane of the drawing in the figure). The light of the P-polarized component is transmitted at a high transmittance with almost no attenuation, and vibrates in a direction perpendicular to the optical axis on a plane perpendicular to the tilt direction of the dichroic mirror (a plane perpendicular to the paper plane in the figure). Since the polarized light component is transmitted with a certain degree of attenuation, the light transmitted through the dichroic mirror becomes light having a strong P-polarized light component. The ratio between the transmittance of the P-polarized light component and the transmittance of the S-polarized light component of light transmitted through one dichroic mirror differs depending on the material of the dichroic mirror, the wavelength of incident light, and the like.
0: 9.

On the other hand, the light reflected by the dichroic mirror is reflected by the dichroic mirror because the S-polarized light component is reflected at a high reflectance and the P-polarized light component is attenuated to some extent, contrary to the transmitted light. The light has a strong S-polarized light component (in this case, the ratio of the reflectance of the S-polarized light component to that of the P-polarized light component is about 10: 9, for example).

The same applies to the light reflected by the light reflecting mirror. The S-polarized light component is reflected at a high reflectance, while the P-polarized light component is attenuated to some extent. Not noticeable,
The light reflected by the light reflecting mirror also has a strong S-polarized light component.

In the above embodiment, since the light incident system on each of the liquid crystal panels 7R, 7G, 7B is configured as described above, the red light R
Is reflected by the blue light separating dichroic mirror 16a and the red-green light reflecting mirror 18, passes through the red-green light separating dichroic mirror 16b, is reflected by the red light reflecting mirror 19, and enters the red image display liquid crystal panel 7R. The green light G is reflected by all of the blue light separating dichroic mirror 16a, the red-green light reflecting mirror 18, the red-green light separating dichroic mirror 16b, and the red light reflecting mirror 19, and enters the green image display liquid crystal panel 7G. , Blue light B
Passes through the dichroic mirror 16a for blue light separation,
Since the light is reflected by the three blue light reflecting mirrors 17a, 17b, and 17c and enters the blue image display liquid crystal panel 7B,
Light incident on each of the liquid crystal panels 7R, 7G, 7B is all light having a strong S-polarized component.

That is, looking at blue light B, for example, the blue light B passes through the blue light separating dichroic mirror 16a and is separated into blue light B, and the S-polarized light component is attenuated as shown in FIG. Although the P-polarized light component in the P direction becomes strong light, this blue light B is thereafter reflected by three blue light reflecting mirrors 17a, 17b, and 17c and guided to the blue image display liquid crystal panel 7B. , And enters the blue image display liquid crystal panel 7B with almost no attenuation of the S-polarized component.

Since the P-polarized light component of the blue light B is attenuated each time it is reflected by the blue light reflecting mirrors 17a, 17b and 17c, the blue light B is reflected by the first blue light reflecting mirror 17a. Then, the P-polarized light component is attenuated to become light in which the S-polarized light component and the P-polarized light component are substantially equal, and further reflected by the blue light reflecting second mirror 17b and the third mirror 17c, thereby reducing the P-polarized light component. Decays heavily.
That is, the blue light B incident on the blue image display liquid crystal panel 7B is light that has been transmitted once and reflected three times.
It is a strong light having an S-polarized component only once.

The same applies to the red light R incident on the red image display liquid crystal panel 7R.
Also, since the red light R is transmitted through one transmission and three reflections, the red light R also has an S-polarized light component which is attenuated only once by transmission.
It is light with a strong polarization component. The green light G incident on the green image display liquid crystal panel 7G is light having no transmission and having undergone four reflections. Therefore, this green light G is a light having a strong S-polarized component with almost no attenuation of the S-polarized component. It is.

On the other hand, the liquid crystal panels 7R, 7G, 7B
Respectively adjust the direction of the polarization axis of the incident light polarizing plate 8 to the direction of oscillation of the S-polarized light components of the red, green, and blue lights incident on the liquid crystal panels 7R, 7G, and 7B. The same liquid crystal panel is twisted at approximately 90 degrees or 270 degrees with respect to the polarization axis direction of the light polarizing plate 8 as a reference. It is provided in parallel with the polarization axis direction of the polarizing plate 8.

That is, each of the liquid crystal panels 7R, 7G,
7B uses the S-polarized light component of the light incident thereon as incident light, and the red, green, and blue light incident on each of the liquid crystal panels 7R, 7G, and 7B has a strong S-polarized light component as described above. Light, and this S-polarized component light is incident light polarizer 8
Is transmitted to the liquid crystal panels 7R, 7G, and 7B, so that high-intensity light can be incident on all of the liquid crystal panels 7R, 7G, and 7B.
The red, green, and blue lights transmitted (emitted) through R, 7G, and 7B, and further transmitted through the image forming polarizing plate 9 to become image light all become high-luminance light. It should be noted that the image light of each color is s-polarized light because the polarization axis direction of the image forming polarizing plate 9 of each of the liquid crystal panels 7R, 7G, and 7B is parallel to the polarization axis direction of the incident light polarizing plate 8. Remains.

The red, green, and blue image lights transmitted through the liquid crystal panels 7R, 7G, and 7B and the image forming polarizing plate 9 are incident on the image synthesizing dichroic prism 11, respectively. Red,
The three primary color lights RGB of green and blue are combined into one overlapped full-color image light, and enlarged and projected by the projection lens 10.

In this case, of the red, green, and blue image lights (S-polarized light components) incident on the image synthesizing dichroic prism 11, the red image light and the blue image light are refracted by the dichroic prism 11. Therefore, similarly to the reflection of light by the mirror, the light is emitted from the dichroic prism 11 with almost no attenuation, whereas the green image light traveling straight through the dichroic prism 11 is transmitted through the dichroic mirrors 16a, 16b, 16c. However, as described above, the green light G incident on the green image display liquid crystal panel 7G is light that has not been transmitted and has undergone four reflections, and is therefore a light for red image display. The intensity of the S-polarized component by one transmission of the red light R and the blue light B incident on the liquid crystal panel 7R and the blue image display liquid crystal panel 7B. Because there is a strong light, green image light emitted from the dichroic prism 11 is approximately equal intensity light and red image light and blue image light by the light attenuation of the dichroic prism 11. Therefore, the full-color image light synthesized by the dichroic prism 11 is an image light having a good color balance in which the light intensities of red, green and blue are almost equal.

On the other hand, the projection mirrors 5 and 6 forming refraction optical paths for guiding the light projected from the projection unit 4 by the projection lens 10 toward the transmission type screen 2 on the front surface of the case are respectively provided on the screen 2. Image light of each color forming a full-color image to be displayed, that is, orthogonal to the vibration direction of red, green, and blue light transmitted through each of the liquid crystal panels 7R, 7G, and 7B and further transmitted through the image forming polarizing plate 9. Are arranged in an inclined direction.

The vibration direction of the light forming the image displayed on the screen 2 is the direction of the polarization axis of the image forming polarizing plate 9, and therefore, the projection mirrors 5, 6
What is necessary is just to arrange it inclining in the direction orthogonal to the polarization axis of the polarizing plate 9 for image formation.

The reason why the inclination directions of the projection mirrors 5 and 6 are set as described above is to project light forming an image displayed on the screen 2 onto the screen 2 with almost no attenuation.

That is, the projection mirrors 5, 6 are tilted in the same direction as the light reflection mirrors 17a, 17b, 17c, 18, 19, 20 constituting the light incidence system to the liquid crystal panels 7R, 7G, 7B. To reflect the S-polarized component light oscillating in the direction orthogonal to
Image light of each color forming a full-color image displayed on the screen 2, that is, red, green, and blue light from the liquid crystal panels 7R, 7G, and 7B are all S-polarized light components as described above. If the projection mirrors 5 and 6 are tilted as described above, red light from each of the liquid crystal panels 7R, 7G and 7B can be obtained.
Green and blue lights are reflected by the projection mirrors 5 and 6 with high reflectance.

Therefore, according to the above-mentioned projection type liquid crystal display device, while the projection optical path from the liquid crystal panels 7R, 7G, 7B to the screen 2 is a bent optical path provided with the projection mirrors 5, 6, the screen 2 Screen 2 with little attenuation of the light forming the image to be displayed
And a bright image can be displayed on the screen 2. The red, green, and blue lights from the liquid crystal panels 7R, 7G, and 7B are hardly attenuated.
, The full-color image light synthesized by the dichroic prism 11 is directly enlarged, red, green,
A full-color image with a good color balance and a substantially equal blue light intensity can be displayed on the screen 2.

The lenticular lens 3 formed on the surface of the transmissive screen 2 on the front of the case diffuses the image light projected from the back side of the screen 2 and emitted to the screen surface side to diffuse the screen projection image. The lenticular lens 3 on the screen surface is used to widen the viewing angle, as shown in FIGS. 1 and 3.
The stripe-shaped minute width lens portions 3a, 3 are arranged in a direction (vertical direction in this embodiment) orthogonal to the vibration direction of the image light reflected on the projection mirrors 5, 6 and projected on the screen 2.
a is formed.

The reason for this is to reduce the reflection of the image light on the surface of the lenticular lens 3, and the lens portions 3a, 3a of the lenticular lens are formed.
Is the smallest when the screen incident light is light that vibrates in the width direction of the lens portion 3a (bending direction of the lenticular surface), the lens portions 3a of the lenticular lens 3 have the same reflectivity. Is formed in the direction orthogonal to the vibration direction of the image light reflected by the projection mirrors 5 and 6 as described above, the image light reflected by the projection mirrors 5 and 6, that is, the light of the S-polarized component Each lens unit 3 for the lenticular lens 3 on the surface
As shown in FIG. 3, the light oscillating in the width direction of a and 3a is incident on the screen 2.

Since the red, green, and blue lights RGB of the full-color image light incident on the screen 2 are all oscillating lights (light of an S-polarized component) in the same direction, the red, green, and
Since all of the blue light RGB is transmitted to the screen surface side with almost no surface reflection at the lenticular lens 3, the full-color image viewed from the front side of the apparatus is an image with good color balance and high brightness.

In the above embodiment, the dichroic mirrors 16a, 16a, 1b are arranged such that the light incident system on the liquid crystal panel faces the light incident surface of each of the liquid crystal panels 7R, 7G, 7B.
Although a mirror is arranged to make each color light separated by 6b incident on each liquid crystal panel as light having a strong polarization component in the same direction, the light incident system is not limited to the structure of the above embodiment. Absent.

In the above embodiment, each liquid crystal panel 7
An image forming polarizing plate 9 is provided on each of the light emitting surfaces of R, 7G, and 7B. Only one image forming polarizing plate 9 is provided on the emitting surface of the dichroic prism 11, and each of the liquid crystal panels 7R, 7G, The light transmitted through 7B may be commonly used as image light, and the polarization axis of the image forming polarizing plate 9 may be changed in direction of the polarization axis of the incident light polarizing plate 8 of each of the liquid crystal panels 7R, 7G, and 7B. It may be provided substantially perpendicular to the axis.

However, when the polarization axis of the image forming polarizing plate 9 is substantially orthogonal to the polarizing axis of the incident light polarizing plate 8, the light transmitted through the incident light polarizing plate 8 and incident on each of the liquid crystal panels 7R, 7G, 7B. And the vibration direction of the image light transmitted through the image forming polarizing plate 9 is shifted by approximately 90 degrees.
When the light of each color separated by the dichroic mirrors 16a and 16b is incident on each of the liquid crystal panels 7R, 7G and 7B as light having a strong polarization component in the same direction by the mirror, the light passes through each of the liquid crystal panels 7R, 7G and 7B. And red, green, and the like that have passed through the image forming polarizing plate 9 and become image light.
All the blue light becomes high-brightness light.

Also in this case, the liquid crystal panels 7R, 7
The projection mirrors 5 and 6 forming a refraction optical path from G and 7B to the screen 2 are used to transmit light forming an image displayed on the screen 2, that is, polarized light that passes through each of the liquid crystal panels 7 R, 7 G and 7 B and further forms image forming polarized light. If the liquid crystal panels 7R, 7R are arranged in such a manner as to be inclined in a direction orthogonal to the vibration directions of the red, green, and blue light transmitted through the plate 9, as in the above-described embodiment.
Since the red, green and blue lights from G and 7B are reflected by the projection mirrors 5 and 6 with high reflectance and can be projected onto the screen 2 with almost no attenuation, the full-color image displayed on the screen 2 can be displayed in red, green and blue. A high-quality image can be obtained in which the intensities of the green and blue colors are balanced.

Further, in the above embodiment, the liquid crystal panel facing the projection lens 10 via the dichroic prism 11 is a green image display liquid crystal panel 7G, and the liquid crystal panels arranged on both sides of the dichroic prism 11 are red and blue image display. Liquid crystal panels 7R and 7B,
The arrangement of these liquid crystal panels 7R, 7G, 7B is not limited to the above embodiment.

[0057]

According to the projection type liquid crystal display device of the present invention, a light source
These lights enter the liquid crystal panel and exit the liquid crystal panel
The illuminated light through a bent optical path with a projection mirror.
Projection-type liquid crystal that displays images on a projection screen
In the display device, a projection mirror constituting the bent optical path
Form the image displayed on the screen
To be almost orthogonal to the vibration direction of the
And the lens portion of the lenticular screen
The length direction is a direction substantially orthogonal to the light vibration direction.
The projection mirror.
Since the image light is reflected with higher reflectance, the screen
The image light reaching the light source is not attenuated, and
Image light is transmitted with higher transmittance on a color screen
As a result, the image light from the screen exits without attenuation
A bright image can be displayed well.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a projection type liquid crystal display device showing one embodiment of the present invention.

FIG. 2 is an enlarged view of a projection unit in the display device.

FIG. 3 is an enlarged sectional view taken along the line III-III of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Case 2 ... Screen 5, 6 ... Projection mirror 7R, 7G, 7B ... Liquid crystal panel 8 ... Incident light polarizing plate 9 ... Image forming polarizing plate 10 ... Projection lens 11 ... Image synthesis dichroic prism 12 ... Light source 16a, 16b ... dichroic mirrors 17a, 17b, 17c, 18, 19, 20 ... light reflecting mirrors

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03B 21/28 G02F 1/13 505 G02F 1/1335 520 G03B 33/12 H04N 5/74

Claims (2)

(57) [Claims] A light from a light source is incident on a liquid crystal panel.
The light emitted from the liquid crystal panel is bent by a projection mirror.
Via the light pathLenticularProject the image on the screen
In the projection type liquid crystal display device for displaying, the inclination direction of the projection mirror forming the refraction optical path is set to
LenticularForm an image to be displayed on the screen
For the direction of light oscillationWhen they are arranged almost orthogonally
Together, The length direction of the lens part of the lenticular screen
A direction substantially orthogonal to the light vibration direction. Features
Projection type liquid crystal display device. 2. The projection type liquid crystal according to claim 1, wherein an inclination direction of the projection mirror is orthogonal to a polarization axis of an image forming polarizing plate on which light emitted from the liquid crystal panel is incident. Display device.