JPH0651262A - Projection liquid crystal display - Google Patents

Abstract

PURPOSE:To use a projection lens having an F value equal to that obtained when a lenticular microlens and a polarizing optical system are used independently of each other by combining the lenticular microlens and the polarizing optical system together in using them. CONSTITUTION:A projection type liquid crystal display is so designed that the direction of alignment of lenticular microlenses 6 is perpendicular to the direction of alignment of first and second outgoing beams 5, 6 of light emitted from a polarizing optical system 3.

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, and more particularly to a projection type liquid crystal display device suitable for applying both a microlens and a polarization conversion optical system, which are techniques for increasing the brightness of a projected image on a screen. Type liquid crystal display device.

[0002]

2. Description of the Related Art Conventionally, as a technique for increasing the brightness of a projected image on a screen in a projection type liquid crystal display device,
Microlenses and polarization conversion optical systems have been proposed.

A technique for increasing the brightness by using a microlens is disclosed in, for example, Japanese Patent Application Laid-Open No. 57-157215, and the aperture ratio of the liquid crystal light valve is provided by a microlens provided corresponding to each pixel of the liquid crystal light valve. Is to improve.

On the other hand, in the technique of increasing the brightness by using a polarization conversion optical system, for example, as described in Japanese Patent Laid-Open No. 61-90584, an incident light beam from a light source is divided into a first emission light beam and a second light beam in the same polarization direction. Of the first and second outgoing light fluxes, and both of them are used as illumination light for the liquid crystal light valve.

The techniques such as the microlens and the polarization conversion optical system can be used independently to obtain the effect of increasing the brightness.

[0006]

However, when both the microlens and the polarization conversion optical system are used in combination at the same time, it has become clear that the following problems occur. Hereinafter, this problem will be described in detail with reference to the drawings.

FIGS. 4 and 5 are a side view and a top view of a conventional projection type liquid crystal display device using a microlens, respectively. The incident light flux 2 from the light source 1 passes through the mirror 10 and
It enters the microlens 11. Micro lens 11
Are provided corresponding to each pixel of the liquid crystal light valve 7, and collect light at the opening of the liquid crystal light valve 7 to improve the aperture ratio. Light flux 1 emitted from the liquid crystal light valve 7
2 is enlarged and projected on a screen (not shown) via the projection lens 9.

For the sake of simplicity, only the luminous flux incident on the center of the liquid crystal light valve 7 will be described. The angle range of the incident light beam 2 on the microlens 7 is a1, and the microlens 7 is
The angular range of the outgoing light flux 12 from is a2, the F value of the microlens 7 is F1, and the F value of the projection lens 9 is F2. Angle range a2 of the luminous flux 12 emitted from the microlens 11
Is the angular range a1 of the incident light beam 2 on the microlens 11.
To the angle range of the microlens 11 having an F value of F1. That is,

[0009]

## EQU00001 ## a2 = a1 + 2.times.arcsin (1 / (2.times.F1)). The F-number F2 of the projection lens is calculated using this angle range a2.

[0010]

## EQU00002 ## F2 = 1 / (2.times.sin (a2 / 2)). For example, if a1 = 10 ° and F1 = 5.7, then a2 = 20 ° and F2 = 2.9.

Next, FIGS. 6 and 7 are a side view and a top view of a projection type liquid crystal display device using a polarization conversion optical system, respectively. An incident light beam 2 from the light source 1 is separated into a first outgoing light beam 4 and a second outgoing light beam 5 via a polarization beam splitter 3a and a mirror 3b of a polarization conversion optical system 3, both of which are liquid crystal light valves 7 Is used as the illumination light. The light emitted from the liquid crystal light valve 7 is enlarged and projected on a screen (not shown) via the projection lens 9.

For simplicity of explanation, the liquid crystal light valve 7
Only the luminous flux incident on the center of is mentioned. The vertical angle range of the incident light beams 4, 5 to the liquid crystal light valve 7 is v1, the horizontal angle range is h1, and the liquid crystal light valve 7 is
It is assumed that the vertical angle range of the outgoing light beam 12 from is v2, the horizontal angle range is h2, and the F value of the projection lens 9 is F2. The vertical angle range v1 of the incident light beams 4, 5 to the liquid crystal light valve 7 is equal to the angular range a1 of the incident light beam 2 from the light source 1. That is, v1 = a1. On the other hand, the horizontal angular range h1 of the incident light beams 4, 5 to the liquid crystal light valve 7 is approximately twice the vertical angular range v1 of the incident light beams 4, 5 to the liquid crystal light valve 7. That is, h
1 = 2 × v1. Further, since the liquid crystal light valve 7 is not provided with the microlens 6, v2 = v1,
h2 = h1. Here, since h2> v2, the F value F2 of the projection lens 9 is

[0013]

## EQU00003 ## F2 = 1 / (2.times.sin (h2 / 2)). For example, in the case of a1 = 10 °, h2 = 20
And F2 = 2.9.

Next, FIGS. 8 and 9 are a side view and a top view of a projection type liquid crystal display device using the microlens 11 and the polarization conversion optical system 3, respectively. Incident light flux 2 from light source 1
Is separated into a first outgoing light beam 4 and a second outgoing light beam 5 via the polarization beam splitter 3a and the mirror 3b of the polarization conversion optical system 3, both of which enter the microlens 11. The microlens 11 is provided corresponding to each pixel of the liquid crystal light valve 7.
The light is condensed in the opening of the to improve the aperture ratio. The light flux 13 emitted from the liquid crystal light valve 7 is enlarged and projected on a screen (not shown) via a projection lens 14.

For simplicity, only the luminous flux incident on the center of the liquid crystal light valve 7 will be described. The angle range in the vertical direction of the incident light beams 4 and 5 to the microlens 11 is v1,
The angle range in the horizontal direction is h1, the angle range in the vertical direction of the light flux 13 emitted from the liquid crystal light valve 7 is v2, the angle range in the horizontal direction is h2, the F value of the microlens 11 is F1, and the F value of the projection lens 14 is Let it be F2. Micro lens 11
The angular range v1 of the incident light beams 4 and 5 in the vertical direction is equal to the angular range a1 of the incident light beam 2 from the light source 1. That is, v1 = a1. On the other hand, the horizontal angular range h1 of the incident light beams 4, 5 to the microlens 11 is the vertical angular range v of the incident light beams 4, 5 to the microlens 11.
It is almost twice as large as 1. That is, h1 = 2 × v1.
Here, since the liquid crystal light valve 7 is provided with the microlens 11,

[0016]

## EQU00004 ## h2 = h1 + 2.times.arcsin (1 / (2.times.F1)) v2 = v1 + 2.times.arcsin (1 / (2.times.F1)). Here, since h2> v2, the projection lens 1
The F value F2 of 4 is

[0017]

F2 = 1 / (2 × sin (h2 / 2)) For example, in the case of a1 = 10 ° and F1 = 5.7,
h1 = 20 °, h2 = 30 °, and F2 = 1.9.

As described above, when the microlens 11 and the conversion / conversion optical system 3 are combined, the projection lens 14 having a smaller F value is required. The projection lens 14 having a small F value generally has a large aperture and has a large number of lens components, so that the projection lens 14 becomes large in size and expensive.

Therefore, it is an object of the present invention to use a projection lens having an F-number equivalent to that when a microlens or a polarization conversion optical system is used in combination when a microlens and a polarization conversion optical system are used in combination. Type liquid crystal display device.

[0020]

In order to achieve the above object, in the present invention, the microlens lens is a lenticular type microlens lens, and the direction in which the lenticular type microlenses are arranged and the light emitted from the polarization conversion optical system. The first outgoing light flux and the second outgoing light flux are arranged so that the direction of arrangement thereof is perpendicular to each other.

[0021]

The lenticular type microlenses have a lens action in the direction of arrangement, but have no lens action in the direction orthogonal to the direction of arrangement. Therefore, the angle formed by the light emitted from the liquid crystal light valve increases only in the direction in which the lenticular microlenses are arranged.

On the other hand, similarly in the polarization conversion optical system, the angle formed by the light emitted from the liquid crystal light valve increases only in the direction in which the first emitted light flux and the second emitted light flux emitted from the polarization conversion optical system are arranged. To do.

As described above, both the lenticular type microlens and the polarization conversion optical system increase the angle formed by the light emitted from the liquid crystal light valve only in one direction. Therefore, by allocating the respective increasing directions to the directions orthogonal to each other. The angle at which the emission angle is stretched is not increased.

[0024]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a perspective view of the projection type liquid crystal display device of the present invention. 2 and 3 are a side view and a top view, respectively, of the projection type liquid crystal display device of the present invention. An incident light beam 2 from the light source 1 is separated into a first outgoing light beam 4 and a second outgoing light beam 5 via a polarization beam splitter 3a and a mirror 3b of a polarization conversion optical system 3, both of which are lenticular type micro It is incident on the lens 6. The lenticular type microlens 6 is provided corresponding to each pixel of the liquid crystal light valve 7, and collects light at the opening of the liquid crystal light valve 7 to improve the aperture ratio. The arrangement direction of the lenticular microlenses 6 is configured to be perpendicular to the arrangement direction of the first outgoing light flux 4 and the second outgoing light flux 5 emitted from the polarization conversion optical system 3. There is. The light flux 8 emitted from the liquid crystal light valve 7 is enlarged and projected on a screen (not shown) via a projection lens 9.

For simplicity, only the luminous flux incident on the center of the liquid crystal light valve 7 will be described. The angle range in the vertical direction of the incident light beams 4 and 5 entering the liquid crystal light valve 7 is v1,
The angle range in the horizontal direction is h1, the angle range in the vertical direction of the light beam 8 emitted from the liquid crystal light valve 7 is v2, the angle range in the horizontal direction is h2, and the lenticular lens type microlens 6 is used.
Let F1 be the F-number and F-number of the projection lens 9 be F2. The vertical angle range v1 of the incident light beams 4, 5 to the liquid crystal light valve 7 is equal to the angular range a1 of the incident light beam 2 from the light source 1. That is, v1 = a1. On the other hand, the horizontal angle range h1 of the incident light beams 4 and 5 entering the liquid crystal light valve 7
Is approximately twice the vertical angular range v1 of the incident light beams 4, 5 to the liquid crystal light valve 7. That is, h1 = 2 ×
v1 = 2 × a1. Here, since the liquid crystal light valve 7 is provided with the lenticular type micro lens 6,

[0027]

## EQU00006 ## v2 = v1 + 2.times.arcsin (1 / (2.times.F1)) = a1 + 2.times.arcsin (1 / (2.times.F1)) h2 = h1 = 2.times.a1. Here, if the F value F1 of the lenticular microlens 6 is set so that h2 = v2, the F value F2 of the projection lens 9 will be

[0028]

## EQU00007 ## F2 = 1 / (2.times.sin (h2 / 2)) = 1 / (2.times.sin (a1)), and the F value of the projection lens 9 required when only the polarization conversion optical system 3 is used. Can be the same as At this time,

[0029]

Since a1 = 2 × arcsin (1 / (2 × F1))

[0030]

## EQU9 ## F1 = 1 / (2 × sin (a1 / 2)). Therefore, it can be seen that the relationship of F1 = 2 × F2 substantially holds. That is, the F value F1 of the lenticular microlens 6 may be set to be approximately twice the F value F2 of the projection lens 9.

For example, when a1 = 10 °, h2 = 2
0 °, F2 = 2.9, F1 = 5.8.

As described above, in this embodiment, even though the lenticular type microlens 6 and the polarization conversion optical system 3 are combined, the same microlens 11 and polarization conversion optical system 3 as in the prior art are used. F-number projection lens 9
Could be used.

Since a microlens is generally manufactured by molding an optical resin, birefringence phase difference occurs due to residual strain during processing. In the conventional microlens 11, since the optical axis of birefringence is distributed on the radiation,
No matter which direction the linearly polarized light was made incident, the polarized light was always disturbed to be elliptically polarized light. On the other hand, in the lenticular type microlens 6 used in the present embodiment, the optical axes of birefringence are aligned in the direction parallel to the parallel direction of the lenses, and therefore, this alignment direction and the polarization conversion optical system 3 are arranged. Since the linearly polarized light beams 4 and 5 emitted from the and incident on the lenticular type microlens 6 are arranged so that the polarization directions 4a and 5a thereof are perpendicular to each other, the polarization is not disturbed and becomes an elliptically polarized light. There is also.

[0034]

As described above, according to the present invention,
The lenticular type microlens lens is used as the microlens lens, and the direction of arrangement of the lenticular type microlens and the direction of arrangement of the first outgoing light flux and the second outgoing light flux emitted from the polarization conversion optical system are perpendicular to each other. With this configuration, when the microlens and the polarization conversion optical system are used in combination, it is possible to use the projection lens having the same F value as that when the microlens or the polarization conversion optical system is used alone.

Further, according to the present invention, the arrangement direction of the lenticular type microlenses and the polarization direction of the linearly polarized light incident on the lenticular type microlens are parallel or perpendicular to each other. The polarized light incident on is not disturbed and becomes elliptically polarized light.

[Brief description of drawings]

FIG. 1 is a perspective view of a projection type liquid crystal display device of the present invention.

FIG. 2 is a side view of the projection type liquid crystal display device of the present invention.

FIG. 3 is a top view of the projection type liquid crystal display device of the present invention.

FIG. 4 is a side view of a conventional projection type liquid crystal display device.

FIG. 5 is a top view of a conventional projection type liquid crystal display device.

FIG. 6 is a side view of a conventional projection type liquid crystal display device.

FIG. 7 is a top view of a conventional projection type liquid crystal display device.

FIG. 8 is a side view of a conventional projection type liquid crystal display device.

FIG. 9 is a top view of a conventional projection type liquid crystal display device.

[Explanation of symbols]

1 ... Light source, 2 ... Incident light flux, 3 ... Polarization conversion optical system, 3a ...
Polarization beam splitter, 3b ... Mirror, 4 ... First emitted light flux, 5 ... Second emitted light flux, 6 ... Lenticular microlens, 7 ... Liquid crystal light valve, 8 ... Light flux, 9 ... Projection lens.

Claims (3)

[Claims] 1. A light source, a polarization conversion optical system for separating an incident light beam from the light source into a translational first outgoing light beam and a second outgoing light beam, and a first outgoing light beam emitted from the polarization conversion optical system. A liquid crystal light valve that uses both the first and second emitted light beams as illumination light, a lenticular microlens provided in the liquid crystal light valve, and a projection lens that magnifies and projects the image of the liquid crystal light valve on a screen, Projection type, characterized in that the arrangement direction of the lenticular type microlenses and the arrangement direction of the first outgoing light flux and the second outgoing light flux emitted from the polarization conversion optical system are perpendicular to each other. Liquid crystal display device. 2. An F of a lenticular lens type microlens
The projection type liquid crystal display device according to claim 1, wherein the value is approximately twice the F value of the projection lens. 3. A light source, a polarization conversion optical system that converts an incident light beam from the light source into a linearly polarized light, a liquid crystal light valve that uses an emitted light beam of the linearly polarized light emitted from the polarization conversion optical system as illumination light, and a liquid crystal light. The lenticular type microlens provided corresponding to each pixel of the bulb is provided, and the alignment direction of the lenticular type microlens and the linearly polarized light flux emitted from the polarization conversion optical system and incident on the lenticular type microlens are mutually A projection type liquid crystal display device characterized by being configured to be parallel or vertical.