JP2000193924A - Liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accomplish the miniaturization of a projector, and also, to project an image without causing color unevenness by controlling the focal distance of a light condensing means and a distance from a position where a secondary light source is formed to the front principal plane position of the light condensing means within a specified extent. SOLUTION: Provided that the focal distance of the light condensing means is expressed by f2, the distance from the position where the secondary light source is formed to the front principal plane position of the light condensing means is expressed by Of2, a condition; 1/4 < Of2/f2 < 3/4 is satisfied. By sifting the main plane position of an illuminating/light condensing system from the position where the secondary light source image is formed to a liquid crystal display device 113 side so as to satisfy the condition, the spice of the focal distance f2 of the light condensing system is secured, besides, the open angle of a luminous flux made incident on a dichroic mirror from the secondary light source image 2 through an illuminating/light shielding lens 108 is made smaller on design, then, the color unevenness on a screen is reduced. Besides, by arranging an optical path bending mirror 107 between the secondary light source image and the front main plane position of the illuminating/light condensing means, the system which is made compact as a whole is accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector, and more particularly to, for example, using a polarized light beam from a light source section having a random polarization direction with a uniform polarization direction to brighten an image based on a liquid crystal display device or the like on a screen. More particularly, the present invention relates to a liquid crystal projector suitable for high-brightness, enlarged projection while suppressing color unevenness.

[0002]

2. Description of the Related Art Conventionally, an image is displayed using a liquid crystal panel, the liquid crystal panel is illuminated by a light beam from a light source, and an image based on transmitted light or reflected light from the liquid crystal panel is enlarged and projected on a screen by a projection lens. Various liquid crystal projectors have been proposed.

A TN type liquid crystal panel from which a high-contrast image can be obtained relatively easily utilizes the polarization characteristics of liquid crystal. For this purpose, a polarizing filter such as a polarizer or an analyzer is usually provided before and after the liquid crystal panel. The polarizing filter has a characteristic of transmitting a specific polarization direction of incident light and blocking a polarization direction orthogonal thereto. Therefore, at least half of the light used in the liquid crystal projector is blocked by the polarizing filter, and the brightness of the projected image tends to decrease.

As a lighting device for a liquid crystal projector,
A polarization conversion element that converts incident light into a light beam having a polarization plane in a specific direction and emits the light, and a uniform illumination unit (optical integrator) for uniformly illuminating the irradiated surface.
For example, Japanese Patent Application Laid-Open No. Hei 8-304739 proposes a polarized light illuminating device that illuminates an illuminated area while effectively utilizing a light flux from a light source.

An illumination device using a rod integrator has been proposed, for example, in Japanese Patent Application Laid-Open No. 8-278503.

FIG. 9 is a schematic view of a main part of a polarized light illuminating device proposed in Japanese Patent Application Laid-Open No. 8-304739. In the polarized light illuminating device shown in FIG. 9, reference numeral 310 denotes a polarization conversion element, which is arranged near the condenser lens array 304. The polarization separation prism array (polarization conversion element) 310 is formed of a plate-like element in which a plurality of polarization beam splitters 305 and a total reflection prism unit 306 are arranged as one unit (optical unit).

Reference numeral 303 denotes a first lens plate, of which one array lens 307 condenses the image of the light source 301 on the corresponding array lens 308 of the condenser lens array 304 as a secondary light source image, and then polarizes the image. Beam splitter 3
The light enters the optical unit 05. The polarizing beam splitter 305 splits the incident light into two linearly polarized lights (P-polarized light and S-polarized light) whose polarization planes are orthogonal to each other. Among them, the linearly polarized light (for example, P-polarized light) transmitted through the polarization beam splitter 305 is inverted in phase by 90 degrees by a half-wave plate 309 disposed on the exit surface of the plate-shaped polarization conversion element 310, and the transmitted light is transmitted. Is linearly polarized light (S-polarized light) having a different polarization plane.

On the other hand, the linearly polarized light (S-polarized light) reflected by the polarization beam splitter 305 is further reflected by a total reflection section 306.
And is emitted in the same direction as the transmitted light. However,
Since the half-wave plate 309 is not applied to the reflected light emitting portion, the transmitted light (P-polarized light) has the same polarization plane as the phase-converted light (S-polarized light).

Arranged lenses 307 of first lens plate 303
Are eccentric and have a positive refractive power as a whole. Thus, the light beam from the first lens plate 303 is emitted in parallel and guided to the polarization conversion element 310.

Here, the reason why the light is guided to the polarization conversion element 310 with substantially parallel light is to minimize the angle dependence of the polarization beam splitter 305. The linearly polarized light having the same polarization plane is configured to illuminate the liquid crystal panel surface 312 in a rectangular shape by the condenser lens 311 on the emission side.

The liquid crystal projector shown in FIG. 9 uses a polarizing beam splitter and a half-wave plate to improve the light use efficiency by aligning the vibration planes of the polarization components.

The principal plane position is near the position of the array lens 308 where the secondary light source image is formed, or the condenser lens 311.
Are provided at positions substantially apart from each other by a focal length.

[0013]

In designing an illumination system for a liquid crystal projector, it is important to increase the light use efficiency while considering matching with a projection lens. For example, with respect to an optical system (polarization illuminator) that uses a fly-eye lens and polarization conversion means as described above, shortening the focal length of the illumination condensing system can produce an image of a light source having a finite size. A small image can be formed on the second fly-eye lens.

For this reason, light may be vignetted around the pupil due to the characteristics of the light emission angle distribution of most arc tubes, but the light use efficiency tends to increase as shown in FIG. Further, since the light source image can be formed on the second fly-eye lens in a small size, flicker on the screen surface due to fluctuation of the light source unit is reduced, and the quality is stabilized.

However, when the focal length of the illumination light condensing system is shortened, the color separation system is not used in the configuration disclosed in Japanese Patent Application Laid-Open No. 8-304739 where the main plane position of the illumination light condensing system is very close to the pupil position. Even if the space for arranging is insufficient, even if space can be secured, the apparent light source image position seen from the dichroic mirror is close, so the color characteristics of the color separation film, especially the color in the color separation cross-section direction on the screen, It was difficult to suppress unevenness.

Further, according to the configuration as disclosed in Japanese Patent Application Laid-Open No. Hei 9-112384, when the pupil is seen from the color separation film, the pupil is seen at infinity, so that the occurrence of color unevenness on the screen as described above can be suppressed. However, there is a drawback that the entire apparatus becomes large.

An object of the present invention is to provide a liquid crystal projector capable of projecting an image based on a liquid crystal display device in a reduced size and without uneven illuminance (uneven color).

[0018]

According to a first aspect of the present invention, there is provided a liquid crystal projector comprising: a light source for emitting white light; and a first fly-eye lens for forming a plurality of secondary light sources from light from the light source. A second fly's eye lens disposed near a position where the plurality of secondary light sources are formed, and a light condensing means for superimposing light beams from the plurality of secondary light sources on an irradiated surface;
A color separation unit that separates the light beam passing through the light collection unit into a plurality of color lights; and a light source that condenses the light beam passing through the color separation unit so that the plurality of secondary light sources form an image at a substantially infinite distance. Image forming means provided for each color light, a liquid crystal display device arranged in an optical path through the image forming means for each color light, and color combining for combining each color light transmitted through the liquid crystal display device for each color light. And a projection lens for projecting an image based on the liquid crystal display device for each color light through the color synthesizing means, wherein the focal length of the condensing means is f2 and the secondary light source is formed. When the distance from the position to the front main plane position of the light condensing means is Of2, the following condition is satisfied: 1/4 <Of2 / f2 <3/4.

According to a second aspect of the present invention, there is provided a liquid crystal projector.
2. The method according to claim 1, wherein a random polarization vibration component is aligned in a predetermined direction near the second fly-eye lens.
It is characterized by having polarization conversion means provided with two plates.

According to a third aspect of the invention, there is provided a liquid crystal projector.
In the invention according to claim 2, the polarization conversion means is characterized in that a plurality of light beam splitting elements are combined based on a rod-shaped light beam splitting element having a polarized light beam splitting surface and a reflecting surface.

A liquid crystal projector according to a fourth aspect of the present invention
The invention according to claim 3 is characterized in that the polarized light beam splitting surfaces of the light beam splitting element are arranged in parallel with each other.

A liquid crystal projector according to a fifth aspect of the present invention
The invention according to claim 3 is characterized in that the polarized light beam splitting surface of the light beam splitting element is arranged symmetrically with respect to the optical axis of the illumination system including the light collecting means.

A liquid crystal projector according to a sixth aspect of the present invention
In the invention according to claim 3, 4, or 5, an optical axis from the light source unit to the polarization conversion unit and an optical axis from the condensing unit to the illuminated surface are the same as those of the light beam splitting element stacked in a plurality of stages. It is characterized by being shifted by half the pitch.

According to a seventh aspect of the present invention, there is provided a liquid crystal projector.
The invention according to claim 1, further comprising an optical path bending unit for bending an optical path between a position where the plurality of secondary light sources are formed and a front main plane position of the condensing unit.

The liquid crystal projector according to the invention of claim 8 is:
The invention according to claim 1 is characterized in that the color synthesizing means is formed of a quadrangular prism as a whole by combining four triangular prisms.

According to a ninth aspect of the present invention, there is provided a liquid crystal projector.
The invention according to claim 1 is characterized in that the color synthesizing means comprises at least one quadrangular prism formed by combining two triangular prisms, and at least one dichroic mirror.

According to a tenth aspect of the present invention, in the liquid crystal projector according to the first aspect, the plurality of secondary light sources and the stop position of the projection lens are substantially conjugated.

According to an eleventh aspect of the present invention, in the liquid crystal projector according to the first aspect, a part of the projection lens is disposed between the liquid crystal display device and the color combining means. I have.

A liquid crystal projector according to a twelfth aspect of the present invention is a liquid crystal projector, comprising: a light source for emitting white light; a secondary light source forming means for forming a secondary light source by condensing a light beam from the light source;
A rod-shaped element for totally reflecting the light beam from the secondary light source inside and guiding the light beam to the exit aperture; a relay lens group for taking in the light beam from the rod-shaped element and forming a plurality of tertiary light sources from the secondary light source; A light collecting means for superimposing a light beam from the next light source on the surface to be irradiated, a color separating means for separating the light beam passing through the light collecting means into a plurality of color lights, and condensing the light beam passing through the color separating means. An imaging means provided for each color light such that the plurality of tertiary light sources form an image at infinity; a liquid crystal display device arranged in an optical path through the imaging means for each color light; A liquid crystal projector comprising: a color synthesizing unit that synthesizes each color light transmitted through the liquid crystal display device for each light; and a projection lens that projects an image based on the liquid crystal display device for each color light through the color synthesizing unit. The focal length of the light collecting means is f2,
When the distance from the position where the next light source is formed to the position of the front main plane of the light condensing unit is Of2, the following relationship is satisfied: 1/4 <Of2 / f2 <3/4.

A liquid crystal projector according to a thirteenth aspect of the present invention is the liquid crystal projector according to the twelfth aspect, further comprising a λ / 2 plate near a position where the tertiary light source is formed, for aligning a random polarization vibration component in a predetermined direction. It is characterized by having conversion means.

According to a fourteenth aspect of the present invention, in the liquid crystal projector according to the thirteenth aspect, the polarization conversion means includes:
It is characterized in that a plurality of light beam splitting elements are combined based on a rod-shaped light beam splitting element having a polarized light beam splitting surface and a reflecting surface.

A liquid crystal projector according to a fifteenth aspect of the present invention is the liquid crystal projector according to the fourteenth aspect, wherein:
The polarized light beam separating surfaces are arranged parallel to each other.

According to a sixteenth aspect of the present invention, in the liquid crystal projector according to the fourteenth aspect, the polarized light beam splitting surface of the light beam splitting element is symmetrically arranged with respect to the optical axis of the illumination system including the light collecting means. It is characterized by.

A liquid crystal projector according to a seventeenth aspect of the present invention is the liquid crystal projector according to the twelfth aspect, wherein an optical path bending means for bending an optical path is disposed between the light source unit and the rod-shaped element.

In a liquid crystal projector according to an eighteenth aspect of the present invention, in the seventeenth aspect, the optical path bending means is provided with a reflective film having a wavelength selection characteristic.

A liquid crystal projector according to a nineteenth aspect of the present invention is the liquid crystal projector according to the twelfth aspect, wherein a lens is disposed near the incident surface of the rod-shaped element.

According to a twentieth aspect of the present invention, in the liquid crystal projector according to the nineteenth aspect, the lens surface on the light source side of the lens disposed near the incident surface of the rod-shaped element is a convex surface.

According to a twenty-first aspect of the present invention, in the liquid crystal projector according to the twelfth aspect, the exit surfaces of the rod-shaped elements are arranged at the lens surfaces of the relay lens group disposed closest to the light source unit. And is held in contact with.

A liquid crystal projector according to a twelfth aspect of the present invention is the liquid crystal projector according to the twelfth aspect, wherein the exit surface of the rod-shaped element is held in contact with a parallel flat plate.

According to a twenty-third aspect of the present invention, in the twelfth aspect, when the length of the longitudinal section of the exit surface of the rod-shaped element is D and the length in the optical axis direction is L, 6.5 < It is characterized by satisfying L / D <9.0.

According to a twenty-fourth aspect of the present invention, in the liquid crystal projector according to the twelfth aspect, at least one lens in the relay lens group has an aspherical surface.

The liquid crystal projector according to a twenty-fifth aspect of the present invention is the liquid crystal projector according to the fourteenth, fifteenth or sixteenth aspect, wherein an optical axis from the light source to the polarization conversion means and a light from the light condensing means to the illuminated surface. The axis is shifted by half of the pitch of the plurality of bar-shaped light beam splitting elements.

According to a twenty-sixth aspect of the present invention, in the liquid crystal projector according to the twelfth aspect, an optical path is formed such that an optical path is bent between a position where the plurality of tertiary light sources are formed and a front main plane position of the condensing means. It is characterized by having bending means.

A liquid crystal projector according to a twenty-seventh aspect of the present invention is the liquid crystal projector according to the twelfth aspect, wherein the color synthesizing means is formed of a quadrangular prism formed by combining four triangular prisms. .

According to a twenty-eighth aspect of the present invention, in the liquid crystal projector according to the twelfth aspect, the color synthesizing means comprises at least one of a combination of two triangular prisms.
It is characterized by being constituted by two square prisms and at least one dichroic mirror.

A liquid crystal projector according to a twenty-ninth aspect of the present invention is the liquid crystal projector according to the twelfth aspect, wherein the plurality of tertiary light sources and the vicinity of the stop position of the projection lens are substantially conjugated.

According to a thirtieth aspect of the present invention, in the liquid crystal projector of the first aspect, a part of the projection lens is disposed between the liquid crystal display device and the color synthesizing means. 13. The liquid crystal projector according to claim 12, wherein:

In the liquid crystal projector according to the thirty-first aspect, a light source unit, a first fly-eye lens forming a plurality of secondary light sources from light from the light source unit, and the plurality of secondary light sources are formed. A second fly's eye lens disposed in the vicinity of the position, a condensing means for superimposing light beams from the plurality of secondary light sources on a surface to be irradiated, a liquid crystal display device disposed on the surface to be irradiated, and a liquid crystal display In a liquid crystal projector having a projection lens for projecting an image based on the device, a focal length of the light-collecting means is f2, and a distance from a position where the secondary light source is formed to a front main plane position of the light-collecting means is f2. It is characterized by satisfying 1/4 <Of2 / f2 <3/4 when Of2 is satisfied.

A liquid crystal projector according to a thirty-second aspect of the present invention is the liquid crystal projector according to the thirty-first aspect, further comprising: a polarization conversion unit having a λ / 2 plate near the second fly-eye lens for aligning a random polarization vibration component in a predetermined direction. It is characterized by having.

According to a thirty-third aspect of the present invention, in the liquid-crystal projector according to the thirty-second aspect, the polarization conversion means comprises:
It is characterized in that a plurality of light beam splitting elements are combined based on a rod-shaped light beam splitting element having a polarized light beam splitting surface and a reflecting surface.

A liquid crystal projector according to a thirty-fourth aspect is characterized in that, in the thirty-third aspect, the polarized light beam splitting surfaces of the light beam splitting elements are arranged in parallel to each other.

According to a thirty-fifth aspect of the present invention, in the liquid crystal projector according to the thirty-third aspect, the polarized light beam splitting surface of the light beam splitting element is arranged symmetrically with respect to the optical axis of the illumination system including the condensing means. It is characterized by.

The liquid crystal projector according to a thirty-sixth aspect of the present invention is the liquid crystal projector according to the thirty-third, thirty-fourth, or thirty-fifth aspects, wherein the optical axis from the light source to the polarization conversion means and the light from the light condensing means to the illuminated surface. The axis is shifted by half of the pitch of the light beam splitting elements stacked in a plurality of stages.

A liquid crystal projector according to a thirty-seventh aspect of the present invention is the liquid crystal projector according to the thirty-first aspect, wherein the optical path is bent between a position where the plurality of secondary light sources are formed and a front main plane position of the condensing means. It is characterized by having bending means.

A liquid crystal projector according to a thirty-eighth aspect of the present invention is characterized in that, in the first aspect of the invention, the plurality of secondary light sources and the stop position of the projection lens are substantially conjugated.

A liquid crystal projector according to a thirty-ninth aspect of the present invention is a liquid crystal projector, comprising: a light source unit; secondary light source forming means for converging a light beam from the light source unit to form a secondary light source; A rod-shaped element which is totally reflected by the light-emitting element and guided to the exit aperture, a light beam from the rod-shaped element is taken in, a relay lens group forming a plurality of tertiary light sources from the secondary light source, and a light beam from the plurality of tertiary light sources. In a liquid crystal projector comprising a light collecting means for superimposing on an irradiation surface, and a projection lens for projecting an image based on a liquid crystal display device arranged on the light receiving surface, the focal length of the light collecting means is f2, The distance from the position where the light source is formed to the front main plane position of the light collecting means is Of2.
Where と し た <Of2 / f2 <3/4 is satisfied.

According to a forty-ninth aspect of the present invention, in the liquid-crystal projector according to the thirty-ninth aspect, there is provided a polarized light having a λ / 2 plate near a position where the tertiary light source is formed, for aligning a random polarized vibration component in a predetermined direction. It is characterized by having conversion means.

In a liquid crystal projector according to a forty-first aspect, in the forty-ninth aspect, the polarization conversion means may include:
It is characterized in that a plurality of light beam splitting elements are combined based on a rod-shaped light beam splitting element having a polarized light beam splitting surface and a reflecting surface.

The liquid crystal projector according to a twenty-second aspect of the present invention is the liquid crystal projector according to the forty-first aspect, wherein:
The polarized light beam separating surfaces are arranged parallel to each other.

A liquid crystal projector according to a thirty-third aspect of the present invention is the liquid crystal projector according to the thirty-first aspect, wherein the polarized light beam splitting surface of the light beam splitting element is symmetrically arranged with respect to the optical axis of the illumination system including the light collecting means. It is characterized by.

In a liquid crystal projector according to a forty-fourth aspect, in the thirty-ninth aspect, an optical path bending means for bending an optical path is disposed between the light source unit and the rod-shaped element.

A liquid crystal projector according to a forty-fifth aspect of the present invention is the liquid crystal projector according to the forty-fourth aspect, wherein the optical path bending means is provided with a reflection film having a wavelength selection characteristic.

A liquid crystal projector according to a forty-sixth aspect is characterized in that, in the thirty-ninth aspect, a lens is disposed near an incident surface of the rod-shaped element.

A liquid crystal projector according to a forty-seventh aspect of the invention is characterized in that, in the forty-sixth aspect of the invention, the lens surface on the light source side of the lens disposed near the incident surface of the rod-shaped element is a convex surface.

In a liquid crystal projector according to a forty-eighth aspect of the present invention, in the thirty-ninth aspect, the exit surface of the rod-shaped element is formed by a lens surface of a lens disposed closest to the light source in the relay lens group. And is held in contact with.

A liquid crystal projector according to a fifty-ninth aspect is characterized in that, in the thirty-ninth aspect, the emission surface of the rod-shaped element is held in contact with a parallel flat plate.

A liquid crystal projector according to a fifty aspect of the present invention is the liquid crystal projector according to the thirty-ninth aspect, wherein the length of the longitudinal section of the exit surface of the rod-shaped element is D, and the length in the optical axis direction is L. 6.5 < It is characterized by satisfying L / D <9.0.

A liquid crystal projector according to a fifty-first aspect of the present invention is the liquid crystal projector according to the thirty-ninth aspect, wherein at least one lens in the relay lens group has an aspherical surface.

A liquid crystal projector according to a fifty-second aspect of the present invention is the liquid crystal projector according to the forty-first, forty-second, or forty-third aspects, wherein an optical axis from the light source unit to the polarization conversion means and a light from the condensing means to the illuminated surface. The axis is shifted by half of the pitch of the plurality of bar-shaped light beam splitting elements.

A liquid crystal projector according to a fifty-third aspect of the present invention is the liquid crystal projector according to the thirty-ninth aspect, wherein an optical path is bent between a position where the plurality of tertiary light sources are formed and a front main plane position of the condensing means. It is characterized by having bending means.

A liquid crystal projector according to a fifty-fourth aspect is characterized in that, in the thirty-ninth aspect, the plurality of tertiary light sources and the vicinity of the stop position of the projection lens are substantially conjugated.

A liquid crystal projector according to a fifty-fifth aspect of the present invention provides a light source unit for emitting white light, secondary light source forming means for forming a plurality of secondary light sources from light from the light source unit, and the plurality of secondary light sources. Light collecting means for superimposing the light flux from the light-receiving surface on the surface to be irradiated, a color separating means for separating the light flux passing through the light collecting means into a plurality of color lights, a liquid crystal display device arranged in the optical path, and a light source for each color light. A liquid crystal projector comprising: a color synthesizing unit for synthesizing respective color lights transmitted through the liquid crystal display device; and a projection lens for projecting an image based on the liquid crystal display device for each color light through the color synthesizing unit.焦点 <f2 / f2 <3/4, where f2 is the focal length of the light source, and Of2 is the distance from the position where the secondary light source is formed to the front main plane position of the light condensing means. And

A liquid crystal projector according to a fifty-sixth aspect of the present invention is the liquid crystal projector according to the fifty-fifth aspect, wherein λ /
It is characterized by having polarization conversion means provided with two plates.

In a liquid crystal projector according to a fifty-seventh aspect, in the fifty-sixth aspect, the polarization conversion means comprises:
It is characterized in that a plurality of light beam splitting elements are combined based on a rod-shaped light beam splitting element having a polarized light beam splitting surface and a reflecting surface.

A liquid crystal projector according to a fifty-eighth aspect of the present invention is characterized in that, in the invention of the fifty-seventh aspect, the polarized light beam splitting surfaces of the light beam splitting elements are arranged in parallel with each other.

According to a fifty-ninth aspect of the present invention, in the liquid crystal projector according to the fifty-seventh aspect, the polarized light beam splitting surface of the light beam splitting element is symmetrically arranged with respect to the optical axis of the illumination system including the light collecting means. It is characterized by.

A liquid crystal projector according to a 60th aspect of the present invention is the liquid crystal projector according to the 57th, 58th or 59th aspect, wherein the optical axis from said light source section to said polarization conversion means and the light axis from said focusing means to said illuminated surface. The axis is shifted by half of the pitch of the light beam splitting elements stacked in a plurality of stages.

A liquid crystal projector according to a sixteenth aspect of the present invention is the liquid crystal projector according to the fifty-fifth aspect, wherein the optical path is bent between a position where the plurality of secondary light sources are formed and a front main plane position of the condensing means. It is characterized by having bending means.

The liquid crystal projector according to the invention of claim 62 is characterized in that, in the invention of claim 55, the color synthesizing means comprises a quadrangular prism as a whole by combining four triangular prisms. .

In the liquid crystal projector according to the invention of claim 63, in the invention of claim 55, the color synthesizing means comprises at least one of a combination of two triangular prisms.
It is characterized by being constituted by two square prisms and at least one dichroic mirror.

The liquid crystal projector according to the invention of claim 64 is characterized in that, in the invention of claim 55, the plurality of secondary light sources and the stop position of the projection lens have a substantially conjugate relationship.

A liquid crystal projector according to a sixty-fifth aspect of the present invention is the liquid crystal projector according to the fifty-fifth aspect, wherein a part of the projection lens is disposed between the liquid crystal display device and the color synthesizing means. I have.

A liquid crystal projector according to a 66th aspect of the present invention is the liquid crystal projector according to the 55th aspect, wherein said secondary light source forming means comprises a solid rod-shaped lens.

The liquid crystal projector according to the sixteenth aspect of the present invention provides a liquid crystal projector, a light source unit, a secondary light source forming means for forming a plurality of secondary light sources from light from the light source unit, and a light beam from the plurality of secondary light sources. In a liquid crystal projector including a light-collecting unit that is superimposed on an irradiation surface, a liquid crystal display device disposed on an object to be irradiated, and a projection lens that projects an image based on the liquid crystal display device, the focal length of the light-collecting unit is f2, When the distance from the position where the secondary light source is formed to the front main plane position of the light condensing unit is Of2, the following condition is satisfied: 1/4 <Of2 / f2 <3/4.

A liquid crystal projector according to a sixty-eighth aspect of the present invention is the liquid crystal projector according to the sixty-seventh aspect, wherein λ /
It is characterized by having polarization conversion means provided with two plates.

The liquid crystal projector according to claim 69 is the liquid crystal projector according to claim 68, wherein the polarization conversion means is
It is characterized in that a plurality of light beam splitting elements are combined based on a rod-shaped light beam splitting element having a polarized light beam splitting surface and a reflecting surface.

A liquid crystal projector according to a 70th aspect of the present invention is the liquid crystal projector according to the 69th aspect, wherein the polarized light beam splitting surfaces of the light beam splitting elements are arranged in parallel with each other.

A liquid crystal projector according to a seventy-first aspect of the present invention is the liquid crystal projector according to the sixty-ninth aspect, wherein the polarized light beam splitting surface of the light beam splitting element is symmetrically arranged with respect to an optical axis of an illumination system including the light condensing means. It is characterized by.

A liquid crystal projector according to a seventy-second aspect of the present invention is the liquid crystal projector according to the sixty-ninth aspect, wherein the optical axis from the light source unit to the polarization conversion means and the light axis from the condensing means to the illumination surface The axis is shifted by half of the pitch of the light beam splitting elements stacked in a plurality of stages.

A liquid crystal projector according to a 73rd aspect of the present invention is the liquid crystal projector according to the 67th aspect, wherein the optical path is bent between a position where the plurality of secondary light sources are formed and a front main plane position of the condensing means. It is characterized by having bending means.

A liquid crystal projector according to a seventy-fourth aspect is characterized in that, in the sixty-seventh aspect, the plurality of secondary light sources and the aperture position of the projection lens are substantially conjugated.

A liquid crystal projector according to a seventy-fifth aspect of the present invention is the liquid crystal projector according to the sixty-seventh aspect, wherein the secondary light source forming means comprises a solid rod-shaped lens.

[0093]

(Embodiment 1) FIG. 1 is a schematic view of a main part of Embodiment 1 of the present invention.

This embodiment shows a case where the present invention is applied to a three-panel type liquid crystal projector. In FIG. 1, reference numeral 101 denotes a light source (light source unit), and 102, a reflector.
The light beam from the light source 01 is reflected and emitted as a substantially parallel light beam. 103 is a first fly-eye lens, 104 is a second fly-eye lens, and each of the first and second fly-eye lenses is composed of a plurality of rectangular condenser lenses.

Reference numeral 105 denotes a polarization conversion element which emits incident light with the polarization directions thereof aligned. 106 is a first condenser lens, 107 is a mirror, 108 is a second condenser lens (condensing lens), 109 is a red transmission dichroic mirror, 110 is a blue transmission dichroic mirror, 1
11 is a mirror, 112 (112R, 112G, 112
B) is a field lens, 113 (113R, 113)
G, 113B) is a liquid crystal display device, and 114 is a cross dichroic prism, which combines B, G, and R color lights and emits them from one direction.

115 is a relay lens, 116 is a mirror,
Reference numeral 117 denotes a relay lens, 118 denotes a mirror, and 119 denotes a projection lens. Each image based on the liquid crystal display device 113 is synthesized by the cross dichroic prism 114 and projected on a screen. Reference numeral 120 denotes an aperture in the projection lens 119.

The light source unit 101 is composed of a short arc light source having a good color rendering property such as a metal halide lamp or a xenon lamp and having an arc length of 1.5 mm or less.

In the present embodiment, the light beam from the light source 101 is converted into a substantially parallel light beam by the parabolic reflector 102 and enters the first fly-eye lens 103. The light incident on the fly-eye lens 103 is formed into a plurality of secondary light sources on the pupils of the corresponding rectangular lenses of the second fly-eye lens 104 by the respective rectangular condenser lenses. ing.

Further, on the flat surface of the first fly-eye lens 103, a film for blocking light in the UV (ultraviolet region) and IR (infrared region) other than the visible region is provided. It protects the polarizing plates placed before and after.

Further, the first fly-eye lens 103 and the surface of the liquid crystal display device 113 are configured to maintain a conjugate relationship. However, as a countermeasure against dust adhesion and the like, an adjusting mechanism and the like are provided to slightly reduce the conjugate relationship. I am staggering.

Further, regarding the shape of the second fly-eye lens 104, an optical system using a parabolic mirror is used, and the luminous flux from the arc of the light source 101 having a finite size is efficiently reflected on the liquid crystal display device 113. The first fly-eye lens 103 has the same shape as that of the first fly-eye lens 103 in order to converge light to the first fly-eye lens 103 and also from the viewpoint of easy production.

The light beam emitted from the second fly-eye lens 104 is incident on the polarization conversion element 105 arranged near the converging point where the plurality of condensed images of the secondary light sources are formed, and the light beam vibrates randomly. The faces are aligned in one direction.

Next, the configuration of the polarization conversion element 105 will be described with reference to FIG. The polarization conversion element 105 is obtained by arranging a plurality of light beam splitting elements so as to correspond to the individual lenses of the second fly-eye lens 104, and each element is a polarization splitting surface 7a and an S-polarized light reflected by the polarization splitting surface 7a. 90 light paths
It has a reflecting surface 7b to be bent, and a half-wave plate (λ / 2 plate) 7c provided in the optical path of P-polarized light transmitted through the polarization separating surface 7a or the optical path of reflected S-polarized light.

In FIG. 8, a λ / 2 plate 7c is provided in the optical path of the P-polarized light transmitted through the polarization separation surface 7a. Polarization separation surface 7
a are parallel to each other (note that, in the embodiment described later, the polarization separation surfaces are arranged in opposite directions with respect to the optical axis, but the same effect is obtained).

The light beam incident on the polarization conversion element 105 is separated by the polarization separation surface 7a into S-polarized light and P-polarized light whose polarization directions are orthogonal to each other ((., ← →)). S-polarized light (•) reflected by the reflection surface 7b
Reflected by

Accordingly, a plurality of light beams having the same polarization direction are emitted from the polarization conversion element 105. A plurality of light beams from the polarization conversion element 105 are combined on the liquid crystal display device 113 by the condenser lens 108 and the field lens 112.

In the case where the polarization conversion element 105 as in this embodiment is used, as described above, the first
The optical axis of the block from the condenser lens 106 to the liquid crystal display device 113 is deliberately shifted so that the arrangement of the secondary light source images is symmetrical with respect to the optical axis (by half the pitch of the polarization conversion element 105). . This suppresses the occurrence of color unevenness on the screen.

In the present embodiment, the second fly-eye lens 10
By disposing a polarization conversion element having a λ / 2 plate for aligning random polarization vibration components near 4, high brightness of the set is realized.

As described above, the second fly-eye lens 104
In the vicinity, a second light source image is formed by the first fly-eye lens 103. If the light emitting light source is small or a small light source image can be formed by the first fly-eye lens 103, an empty space of about half the pitch of the lens array is formed for each lens of the second fly-eye lens, and the polarized light beam separation is performed. If the pupil plane can be effectively used by using a polarization conversion element having a surface and a reflection surface, the polarization component can be converted with high efficiency.

Further, as shown in FIG. 6, the polarization conversion element 105 may be configured to be vertically symmetric with respect to the optical axis including the illumination condensing means.

According to this, as shown in FIG. 6, light rays incident on the polarization separation film at an optical axis symmetrical angle respectively illuminate the polarization separation sections on the liquid crystal display device, so that the cause of color unevenness can be canceled. Can be.

Alternatively, when a polarization conversion element having a configuration in which polarization separation surfaces are parallel to each other as in this embodiment is employed, the optical axis from the light source section to the polarization conversion element and the light condensing means to the surface of the liquid crystal display device are used. The optical axes are shifted by about half of the pitch of the rod-shaped polarized light beam splitting elements stacked in a plurality of stages.

According to this configuration, as can be seen from the polarization separation optical path in FIG.
It can be seen that the distribution of the secondary light source image formed near 4 is also asymmetrical with respect to the optical axis on the pupil. Therefore, the luminous flux from the secondary light source image is formed as a tertiary light source image in the vicinity of the stop surface of the projection lens. However, the tertiary light source image naturally has a biased distribution and adverse effects such as uneven brightness on the screen. Exert.

Further, in an optical system in which a color combining system is combined with a cross prism by using a cross prism, the tertiary light source image of the liquid crystal display device is compared with that of the other two colors only in the optical path of the color employing the relay lens system. Are inverted with respect to the optical axis including. For this reason, the polarization separation section of the stop of the projection lens is colored at both ends, causing color unevenness on the screen.

Therefore, in the present embodiment, in order to superimpose the tertiary light source image on the aperture surface for each color, a polarization conversion element in which the polarization separation surface is symmetrically arranged with respect to the optical axis is employed, or the polarization separation surface is used. When they are parallel to each other, they are configured as described above so that the secondary light source image is formed symmetrically with respect to the polarization separation section with respect to the optical axis including the illumination light condensing system.

A light beam from each secondary light source image formed near the second fly-eye lens 104 is condensed on the liquid crystal display device 113 by the second condenser lens 108 composed of two sheets.

With respect to the focusing means (first and second condenser lenses 106 and 108), the focal length f2 = 1
55 (mm) (Units are shown in mm for convenience, but mm
Other units may be used. In the following, the front principal point position is Of2 = 71 from the secondary light source image forming position.
(Mm), and a compact arrangement as shown in FIG. 1 is realized by the above-described effect.

That is, the condition (1) is satisfied. In the present embodiment, the first effect is obtained by shifting the main plane position of the illumination light condensing system from the position where the secondary light source image is formed toward the liquid crystal display device so as to satisfy the conditional expression (1). Due to the focal length f2 of the light-collecting system, which has been set short to realize high luminance, it is possible to secure a space that is too short to dispose the color separation system.

Further, as a second effect, the opening angle of a light beam incident on the dichroic mirror from the secondary light source image can be designed to be small (the apparent pupil position is far from the dichroic mirror) by the illumination condensing lens 108, so that it can be designed on the screen. Color unevenness can be reduced.

Further, the cross dichroic prism 114
In the case of using such a color synthesizing means, the refracting power of the relay lens closest to the light source in the relay lens system can be designed to be small, and this also has an advantageous effect on the imaging performance of the relay lens system.

If the lower limit of conditional expression (1) is exceeded, the principal plane position of the illumination light condensing system is close to the position of the secondary light source image, as described above. It is not preferable because unevenness occurs. Conversely, when the value exceeds the upper limit, it is advantageous for color unevenness, but it is not preferable because the entire apparatus becomes large.

Further, by providing means (mirror 107) for bending the optical path between the secondary light source image formed on the second fly-eye lens 104 and the front main plane position of the illumination condensing means, it is necessary to provide It is possible to arrange the optical elements densely in the projection set,
A compact system as a whole is easily realized.

Further, when considering the field lens 112 as a reference, the apparent pupil position can be set as far as about 270 mm, and the color unevenness on the screen is reduced.

In the present embodiment, since the second condenser lens 108 is composed of two pieces, the refracting power of the illumination light condensing system can be shared, and the light condensing performance on the liquid crystal display device 113 is improved. In addition, the second fly-eye lens 104
Each element up to the condenser lens 108 is provided with an antireflection coat or a reflection coat having a wide band characteristic in order to transmit or reflect white light before being color-separated.

Regarding the color separation system (109, 110), in the present embodiment, due to the characteristics of the lamp 101, approximately equal-magnification relay lens systems 115, 117 are provided in the blue light path and connected to the liquid crystal display device 113B. In particular, without being limited to this example, a red light path may be selected for the relay lens system depending on the characteristics of the lamp 101 and the aim of the white balance. Further, the relay lens system is provided with a coat that matches the wavelength band, and further employs an aspherical lens for improving the imaging performance and light use efficiency.

Color separation dichroic mirrors 109 and 11
If the color unevenness on the screen is remarkable at 0, a gradient film may be employed in the direction of the color separation cross section. In the examples, the mirrors 111, 116 and 118 do not need to have a particularly wide band characteristic, and may be dichroic mirrors having appropriate wavelength selectivity.

In this embodiment, the first and second condenser lenses 106 and 108 and the field lens 11
Reference numeral 2 constitutes one element of the imaging means.

The field lens 112 is the liquid crystal display 1
Although it is desirable to make the light beam telecentrically incident on the projection 13, it is better to optimize the shape without being particularly limited to this depending on the pupil characteristics of the succeeding projection lens 119. In particular,
Unless the pupil with the projection lens 119 is sufficiently matched with respect to each color optical path, color unevenness occurs particularly at the periphery of the screen, and the image quality deteriorates.

The surface of the field lens 112 on the side of the liquid crystal display device 113 or the like may be made flat, and a suitable coating such as a dichroic filter may be applied to improve the color purity. Further, an anti-reflection coating is applied to each surface of the lens constituting the projection lens 119 in order to improve transmittance.

As for the color synthesizing system, a cross dichroic prism 114 is used. That is, it is constituted by a quadrangular prism formed by combining four triangular prisms, whereby the color synthesis system is compactly designed, and the back focus of the projection lens for enlarging and projecting an image based on the liquid crystal display device is designed to be short. To reduce the design load on the projection lens.

By designing the plurality of light source images on the second fly-eye lens 104 and the vicinity of the position of the stop 120 of the projection lens 110 in a substantially conjugate relationship, good matching between the illumination system and the projection lens can be achieved, and High light utilization efficiency is obtained for the entire projector.

It is to be noted that the first and second fly-eye lenses may be constituted by a solid rod-shaped lens in which both are integrated.

In this embodiment, the present invention can be similarly applied to a single-panel type liquid crystal projector. In the present embodiment, the second fly-eye lens does not need to be particularly provided.

(Embodiment 2) FIG. 2 shows Embodiment 2 of the present invention.
FIG.

This embodiment shows a case where the present invention is applied to an illumination system for a three-panel type liquid crystal projector. In FIG. 2, 201 is a light source, 202 is a reflector, and 203 is a first light source.
Fly-eye lens 204, second fly-eye lens, 2
05 is a polarization conversion element, 206 is a mirror, 207 is a condenser lens, 208 is a blue transmission dichroic mirror,
209 is a red transmission dichroic mirror, 210 is a mirror, 211 (211B, 211G, 211R) is a field lens, 212 (212B, 212G, 212R).
Are liquid crystal display devices, 213 (213B, 213G, 213).
R) is a field lens of the projection lens 217, 214 is a blue transmission dichroic mirror, 215 is a mirror, 216
Denotes a color combining prism, 217 denotes a projection lens, and 218 denotes an aperture in the projection lens 217.

The present embodiment is different from the first embodiment shown in FIG. 1 in that the shape of the polarization conversion element 205 is symmetrical with respect to the optical axis including the light condensing system as shown in FIG. In the case of using the polarization conversion element as in the present embodiment, it is not necessary to intentionally shift the optical axis of the block from the condenser lens 207 to the liquid crystal display device 212 with respect to the polarization separation section as described above, and as described in FIG. This makes it possible to suppress the occurrence of color unevenness on the screen.

Thereafter, the light flux from each secondary light source image is condensed on the liquid crystal display device 212 via the field lens 211 by the condenser lens 207 composed of one sheet. With respect to the focusing means (condenser lens 207), the front principal point is located at a position where Of2 = 78 mm from the position where the secondary light source image is formed (second fly-eye lens 204) with respect to the focal length f2 = 150 mm. As a result, a compact arrangement as shown in FIG. 2 is realized by the above-described effect.

When the field lens is considered as a reference, the apparent pupil position can be set as far as about 300 mm, thereby reducing color unevenness on the screen.

In the present embodiment, the condenser lens 20
7 is constituted by one sheet. Regarding the color separation systems 208 and 209, in the present embodiment, the blue transmission dichroic mirror 20 is used.
8 (DM) are installed. This is the projection lens system 217
In this optical path, the blue transmission dichroic mirror 2
An eccentric aberration occurs when the light passes through the light-receiving element 14, and this is a result of considering this and the luminosity characteristics together.

If the generation of the eccentric aberration is to be avoided, the color combining mirror of the blue transmission dichroic mirror 214 and the color combining prism such as the color combining prism 216 and the triangular prism for the mirror 215 may be used.

In this case, the color separation mirror of the blue transmission dichroic mirror 208 is not particularly limited to blue transmission. In the case where color unevenness on the screen is remarkable in the color separation dichroic mirror, an inclined film may be employed in the color separation section direction.

In the examples, the mirrors 210 and 215 do not need to have a particularly wide band characteristic, and may be dichroic mirrors having an appropriate wavelength selectivity.

The field lens of the projection lens system 217 can be designed such that the diameter of each lens from the stop 218 of the color combining prism 216 and the projection lens 217 to the surface of the liquid crystal display device 212 can be designed to be small. Has adopted.

In this embodiment, a color synthesizing prism 216 and a dichroic mirror (blue transmitting dichroic mirror) 214 are used for the color synthesizing system.

In this embodiment, since the color synthesizing system comprises at least one quadrangular prism formed by combining two triangular prisms and at least one dichroic mirror, the back focus of the projection lens becomes long. Would.

However, comparing with the point that the white balance can be easily obtained and the type in which the four prisms shown in FIG. 1 are combined, the light scattering at the junction where the prisms are combined causes shadows on the screen. There are advantages such as a reduction in image quality such as visible lines. In addition, it is possible to obtain the prism at a low cost because the accuracy of the angle and the like is not required on the surface for manufacturing the prism, and either type may be adopted as the color synthesizing system.

When a color combining system of a type combining two prisms is used, the lens LR disposed closest to the liquid crystal display device with respect to the projection lens is changed to the color combining system disposed closest to the liquid crystal display device and the liquid crystal display device. By arranging the liquid crystal display between the projection lens and the liquid crystal display device, the diameter of each lens is reduced from the stop of the projection lens.

When the color synthesizing system is formed by combining two triangular prisms, the color synthesizing prism can be made small as a whole.
If the refracting power of the lens LR is too large, the divergence angle of the light beam incident on the color synthesizing dichroic film becomes large, so that the color unevenness on the screen may be increased. Ffm focal length
m, -0.0033 / mm <1 / ff <
It is preferable that it is in the range of 0.0033 / mm. The other points are the same as those in the first embodiment, and thus detailed description is omitted.

This embodiment can also be applied to a single-panel type liquid crystal projector.

(Embodiment 3) FIG. 3 shows Embodiment 3 of the present invention.
FIG. This embodiment shows a case where the present invention is applied to an illumination system for a three-panel liquid crystal projector. 3, reference numeral 301 denotes a light source, 302 denotes a reflector, 3
03 is a UVIR cut mirror, 304 is a correction lens, 3
Reference numeral 05 denotes a rod-shaped element, which is composed of, for example, a rod integrator.

306 is a parallel plane plate, 307 is a relay lens group, 308 is a polarization conversion element, 309 is mirrors 1 and 31
0 is a condenser lens, 311 is a red transmission dichroic mirror, 312 is a blue transmission dichroic mirror, 31
3 is a mirror, 314 (314R, 314G, 314B)
Are field lenses and 315 (315R, 315G, 3
15B) is a liquid crystal display device, 316 is a cross dichroic prism, 317 is a relay lens, 318 is a mirror, 319
Is a relay lens, 320 is a mirror 4, 321 is a projection lens, and 322 is a stop in the projection lens 321.

The light source 301 has a good color rendering property such as a metal halide lamp or a xenon lamp, and is composed of a short arc light source having an arc length of 1.5 mm or less.

In the present embodiment, the light beam from the light source 301 becomes a condensed light beam by an elliptical reflector 302, is reflected by a mirror 303 that blocks (transmits) UVIR component light, passes through a correction lens 304, and passes through a rod integrator 305. A secondary light source image is formed on the incident surface of.

Here, the reflector 302 and the correction lens 3
04 forms one element of the secondary light source forming means.

In the UVIR cut mirror 303,
In addition to the effect of cutting harmful light beams outside the visible region, the use of a mirror as shown in FIG. 3 contributes to a compact set.

The correction lens 304 has a positive refracting power as a whole. The convex surface on the light source side reduces the magnification of the light source image to take in the light beam into the rod integrator 305, and the concave surface on the rear side is the lens. Has the function of making the reflector surface and the exit surface of the rod conjugate, and has the effect of increasing the light use efficiency as a whole.

The light incident on the rod integrator 305 is based on the principle that the light from a plurality of arc virtual images corresponding to the incident surface illuminates the exit surface in a superimposed manner by the manner of total reflection inside the rod integrator 305. . Therefore, the rod integrator emits light at an angle corresponding to the position where the virtual arc image is formed.

The rod integrator 30 in the present embodiment
5 has a quadrangular prism shape, and has an exit angle equal to the magnitude of the incident angle of the light beam. The exit surface is held in contact with a parallel flat plate 306 to prevent dust and improve light use efficiency. The rod portion is a portion through which white light is transmitted. The material is borosilicate crown glass (specifically, BSL7 (OHARA)) in consideration of internal transmittance characteristics and the like.
It is made of wood. This portion is not limited to the glass rod, and may be formed by a hollow mirror.

The rod integrator 305 converts the luminous flux from the plurality of virtual arc images divided into the relay lens group 3
07 forms a tertiary light source image. The number of light source image divisions at this time is determined by the shape of the rod integrator. In this embodiment, the light source image is divided into a plurality of 9 × 12 tertiary light source images. 308 are arranged.

This polarization conversion element 308 is the same as the type used in the second embodiment. As described above, the light passing through the center of the exit aperture of the rod integrator 305 is sufficiently parallel to the tertiary light source image plane. Since a degree of power is required, an aspherical surface is employed for the final lens surface of the relay lens group 307. Also, a color separation system (311, 31) from the correction lens 304 to the condenser lens 310.
Each element up to 2) is coated with a broadband anti-reflection coating for higher luminance.

Thereafter, the light beam from each tertiary light source image is condensed on the liquid crystal display device 315 by a condenser lens (condensing means) 310 composed of one sheet. This light collecting means 3
10, with respect to the focal length f2 = 120 (mm), the front principal point position is shifted Off from the tertiary light source image formation position.
2 is set to about 53 (mm), and a compact arrangement as shown in FIG. 3 is realized by the above-described effect. Also, when the field lens 314 is considered as a reference, the apparent pupil position can be set as far as about 204 (mm), and color unevenness on the screen is reduced.

A color separation dichroic mirror (31)
In (1,312), when color unevenness on the screen is remarkable, a gradient film may be employed in the direction of the color separation cross section.

As described above, in the present embodiment, as the light source dividing means for dividing the light source image into a plurality of light source images, the rod-shaped element 305 is used instead of the fly-eye lens shown in FIGS.

Further, by providing a means (mirror 303) for bending the optical path between the light source unit 301 and the rod-shaped element 305, it is possible to arrange necessary optical elements with high density in the projection set, and to reduce the size as a whole. The optical system is easily realized. The mirror 303 blocks (transmits) UV and IR component light outside the visible region included in the light beam from the light source unit 301, and has a light reflection characteristic with respect to visible light.

The purpose of blocking UV is to protect a polarizing plate disposed near the liquid crystal display device, and the purpose of blocking IR components is to prevent temperature rise of the device.

Further, in order to efficiently use the light beam from the light source unit 301, a correction lens 304 is arranged near the rod integrator 305. In particular, regarding the correction lens 304, the convex surface on the light source side reduces the image of the light source, and the subsequent concave surface has a function of efficiently condensing the light flux from the end of the light source to the liquid crystal display device, thereby improving the light use efficiency. ing.

However, this rod integrator 305
Regarding the correction lens 304 disposed in the vicinity, the optimum shape of the convex surface in particular greatly changes depending on the specification of the maximum allowable light ray angle (F value of the illumination system) incident on the liquid crystal display device. When the radius of curvature of the convex surface is reduced, the size of the light source image formed on the incident surface of the rod integrator 305 can be made sufficiently small, and an illumination system that is stable against light source fluctuation can be formed. The maximum angle of the light beam incident on the device, that is, the size of the tertiary light source image increases.

Since the maximum allowable angle of the light beam incident on the liquid crystal display device is determined by the aperture diameter (F value) of the succeeding projection lens for enlarging and projecting the picture on the liquid crystal display device, the angle out of this aperture diameter is determined. The light flux becomes light loss and the light use efficiency is reduced. Therefore, the optimum shape of the correction lens 304 disposed near the rod integrator 305 is determined by the balance between the light use efficiency and the flutter level on the screen.

The emission surface of the rod integrator 305 is held in contact with each other by an element having a flat surface on the light source side disposed closest to the light source in the relay lens group 307 or a plane portion of a parallel flat plate. Is preferred.

As a result, since the light is not lost by the emission holding area of the rod integrator, which has been required conventionally, the extra illumination area can be reduced with respect to the illuminated area, and the light use efficiency can be improved. .

Further, since the exit surface of the rod integrator 305 is in contact with the flat portion as described above, the possibility that dusts and other dusts, which pose a problem, will be greatly reduced. Further, the clearance between the flat portion and the rod integrator due to thermal expansion or the like can be secured by holding the rod incident surface side with an elastic spring or the like.

Assuming that the length of the longitudinal section of the exit surface of the rod integrator is D and the length of the rod in the optical axis direction is L, the conditional expression (3) is satisfied as described above.

6.5 <L / D <9.0 ‥‥‥ (3) This conditional expression is a formula that defines the length of the rod integrator in the optical axis direction with respect to the size of the exit aperture, and exceeds the lower limit. And the length of the rod integrator becomes shorter. Therefore, the number of times that light rays (light rays incident at the maximum angle) taken into the rod from the outermost edge of the reflector are totally reflected inside the rod integrator is reduced, and the illuminance uniformity on the liquid crystal display device surface is reduced. Conversely, if the upper limit is exceeded, the length of the rod integrator becomes too long, and the entire device becomes large, and the loss such as light scattering and absorption inside the rod integrator increases,
Not preferred.

It is important that each principal ray passing through the center of the optical axis of the exit surface of the rod integrator forms a tertiary light source image as a light beam substantially parallel to the optical axis. In the present optical system that requires sufficient parallelism from the center to the periphery of the tertiary light source image plane, it is preferable to employ at least one aspheric lens in the relay lens system. In particular, it is effective to adopt the surface closest to the tertiary light source image forming position.

The other points are the same as those of the first embodiment, so that detailed description will be omitted.

(Embodiment 4) FIG. 4 shows Embodiment 4 of the present invention.
FIG.

This embodiment shows a case where the present invention is applied to an illumination system for a three-panel liquid crystal projector. In FIG. 4, reference numeral 401 denotes a light source, 402 denotes a reflector, and 403 denotes UV.
IR cut filter, 404 is a correction lens, 405 is a rod integrator, 406 is a relay lens group, 4
07 is a polarization conversion element, 408 is a mirror, 409 (condensing means) is a condenser lens, 410 is a blue transmission dichroic mirror, 411 is a red transmission dichroic mirror,
12 is a mirror, 413 (413B, 413G, 413).
R) is a field lens, 414 (414B, 414)
G, 414R) is a liquid crystal display device, and 415 (415B, 4
15G, 415R) are field lenses of the projection lens unit 419, 416 is a blue transmission dichroic mirror, 417
Denotes a mirror, 418 denotes a color combining prism, 419 denotes a projection lens, and 420 denotes a stop in the projection lens 419.

This embodiment is different from the third embodiment in that UV
Filter 403 that blocks IR (ultraviolet, infrared) components
It has.

In addition, the emission part of the rod integrator 405 is held in contact with the flat part of the lens closest to the light source in the relay lens group 406.

Regarding the light condensing means, the light flux from each tertiary light source image is condensed on the liquid crystal display device 414 by a condenser lens 409 composed of one sheet. This light collecting means 4
For the focal length f2 = 132 (mm), the front principal point position is shifted Off from the tertiary light source image forming position.
It is set at about 2 = 52 (mm), and a compact arrangement as shown in FIG. 4 is realized by the effect described above.

Also, considering the field lens as a reference, the apparent pupil position can be set as far as about 207 (mm), thereby reducing color unevenness on the screen. In the case where color unevenness on the screen is remarkable in the color separation dichroic mirror, an inclined film may be employed in the color separation section direction.

The other points are the same as those of the synthesizing system of the second embodiment, so that the detailed description will be omitted.

[0183]

According to the present invention, (a-1) an image based on a liquid crystal display device is brightened on a predetermined surface (screen surface),
Moreover, it is possible to achieve a liquid crystal projector capable of projecting without color unevenness.

Further, according to the present invention, (a-2) a liquid crystal projector for projecting a picture such as a liquid crystal display device on a screen brightly and enlarging while suppressing luminance and color unevenness using polarized light having a uniform polarization direction. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a main part of an optical system according to a first embodiment of a liquid crystal projector of the present invention.

FIG. 2 is a schematic diagram of a main part of an optical system according to a second embodiment of the liquid crystal projector of the present invention.

FIG. 3 is a schematic diagram of a main part of an optical system according to a third embodiment of the liquid crystal projector of the present invention.

FIG. 4 is a schematic diagram of a main part of an optical system according to a fourth embodiment of the liquid crystal projector of the present invention.

FIG. 5 shows the relationship between the ratio of the focal length f2 of the illumination light condensing system to the light output on the screen.

FIG. 6 is an explanatory diagram of a color unevenness reducing effect by a polarization conversion element.

FIG. 7 is an explanatory diagram of setting of an optical axis including a lighting unit.

FIG. 8 is an explanatory diagram of the polarization conversion element in FIG. 1;

FIG. 9 is an explanatory view of a conventional polarized illumination device.

[Explanation of symbols]

 Reference Signs List 101 light source 102 reflector 103 first fly-eye lens 104 second fly-eye lens 105 polarization conversion element 106 condenser lens 107 mirror 108 condenser lens 109 dichroic mirror 110 dichroic mirror 111 mirror 112 field lens 113 liquid crystal display device 114 cross dichroic prism 115 relay lens 116 Mirror 117 Relay lens 118 Mirror 119 Projection lens 120 Aperture 216 Color combining prism 214 Dichroic mirror 304 Correction lens 305 Rod integrator 306 Parallel plane plate 307 Relay lens

Claims (75)

[Claims] 1. A light source unit for emitting white light, a first fly-eye lens forming a plurality of secondary light sources from light from the light source unit, and a vicinity of a position where the plurality of secondary light sources are formed A second fly-eye lens, a light condensing means for superimposing light beams from the plurality of secondary light sources on a surface to be illuminated, and a color separation device for separating the light beam passing through the light condensing means into a plurality of color lights Means for focusing each light beam through the color separation means so that the plurality of secondary light sources form an image at approximately infinity; and an image forming means provided for each color light. A liquid crystal display device arranged in an optical path through an image unit, a color combining unit that combines respective color lights transmitted through the liquid crystal display unit for each color light, and a liquid crystal display device of each color light through the color combining unit. A projection lens for projecting an image based on When the focal length is f2 and the distance from the position where the secondary light source is formed to the front main plane position of the light condensing unit is Of2, the following inequality is satisfied: 1/4 <Of2 / f2 <3/4. LCD projector. 2. The liquid crystal projector according to claim 1, further comprising: a polarization conversion unit having a λ / 2 plate for aligning a random polarization vibration component in a predetermined direction near the second fly-eye lens. 3. The polarization conversion means is based on a rod-shaped light beam splitting element having a polarized light beam separation surface and a reflection surface,
3. The liquid crystal projector according to claim 2, comprising a plurality of light beam splitting elements combined. 4. The liquid crystal projector according to claim 3, wherein the polarized light beam splitting surfaces of the light beam splitting elements are arranged in parallel with each other. 5. The liquid crystal projector according to claim 3, wherein the polarized light beam splitting surface of the light beam splitting element is symmetrically arranged with respect to an optical axis of the illumination system including the light collecting means. 6. An optical axis from the light source unit to the polarization conversion unit and an optical axis from the light collecting unit to the illuminated surface,
6. The liquid crystal projector according to claim 3, wherein the liquid crystal projector is shifted by a half of a pitch of the light beam splitting elements stacked in a plurality of stages. 7. The liquid crystal projector according to claim 1, further comprising an optical path bending unit that bends an optical path between a position where the plurality of secondary light sources are formed and a front main plane position of the condensing unit. . 8. The liquid crystal projector according to claim 1, wherein said color synthesizing means comprises a quadrangular prism formed by combining four triangular prisms. 9. The liquid crystal projector according to claim 1, wherein said color synthesizing means includes at least one quadrangular prism formed by combining two triangular prisms, and at least one dichroic mirror. . 10. The liquid crystal projector according to claim 1, wherein the plurality of secondary light sources and a stop position of the projection lens have a substantially conjugate relationship. 11. The liquid crystal projector according to claim 1, wherein a part of the projection lens is disposed between the liquid crystal display device and the color synthesizing unit. 12. A light source unit that emits white light, a secondary light source forming unit that collects a light beam from the light source unit to form a secondary light source, and totally reflects the light beam from the secondary light source inside. A rod-shaped element that guides the light to the exit aperture, a relay lens group that takes in the light beam from the rod-shaped element and forms a plurality of tertiary light sources from the secondary light source, and a light beam from the plurality of tertiary light sources on an irradiated surface. A light condensing means for superimposing the light beam, a color separating means for separating the light beam passing through the light collecting means into a plurality of color lights, and a light beam passing through the color separating means for converging the plurality of tertiary light sources. Imaging means provided for each color light so as to form an image at a distance, and a liquid crystal display device arranged in an optical path through the imaging means for each color light,
In a liquid crystal projector including a color combining unit that combines the respective color lights transmitted through the liquid crystal display device for each color light, and a projection lens that projects an image based on the liquid crystal display device of each color light through the color combining unit, When the focal length of the light condensing means is f2 and the distance from the position where the tertiary light source is formed to the front main plane position of the light condensing means is Of2, １ ／ <Of2 / f2 <3/4. Liquid crystal projector characterized by satisfaction. 13. The liquid crystal projector according to claim 12, further comprising: a polarization converter having a λ / 2 plate for aligning a random polarization vibration component in a predetermined direction near a position where the tertiary light source is formed. . 14. The liquid crystal according to claim 13, wherein said polarization conversion means is based on a rod-shaped light beam splitting element having a polarized light beam splitting surface and a reflecting surface, and is formed by combining a plurality of light beam splitting elements. projector. 15. The liquid crystal projector according to claim 14, wherein the polarized light beam splitting surfaces of the light beam splitting elements are arranged in parallel with each other. 16. The liquid crystal projector according to claim 14, wherein the polarized light beam splitting surface of the light beam splitting element is arranged symmetrically with respect to an optical axis of an illumination system including the light collecting means. 17. Between the light source unit and the rod-shaped element,
13. The liquid crystal projector according to claim 12, further comprising an optical path bending unit for bending an optical path. 18. The liquid crystal projector according to claim 17, wherein said optical path bending means is provided with a reflection film having a wavelength selection characteristic. 19. The liquid crystal projector according to claim 12, wherein a lens is arranged near an incident surface of said rod-shaped element. 20. The liquid crystal projector according to claim 19, wherein a lens surface on the light source side of a lens arranged near the incident surface of the rod-shaped element is a convex surface. 21. The emission surface of the rod-shaped element is held in contact with each other on a lens surface of a lens disposed closest to the light source unit in the relay lens group. 12 liquid crystal projectors. 22. The liquid crystal projector according to claim 12, wherein an emission surface of the rod-shaped element is held in contact with a parallel flat plate. 23. When the length of the longitudinal section of the exit surface of the rod-shaped element is D and the length in the optical axis direction is L, 6.5 <L / D <9.0 is satisfied. The liquid crystal projector according to claim 12. 24. At least one of the relay lens groups
13. The liquid crystal projector according to claim 12, wherein each of the lenses has an aspherical surface. 25. An optical axis from the light source section to the polarization conversion means and an optical axis from the light condensing means to the illuminated surface are only half the pitch of the plurality of stacked bar-shaped light beam splitting elements. 2. The method of claim 1, wherein the object is shifted.
4, 15 or 16 liquid crystal projectors. 26. The liquid crystal projector according to claim 12, further comprising an optical path bending unit for bending an optical path between a position where the plurality of tertiary light sources are formed and a front main plane position of the light collecting unit. . 27. The liquid crystal projector according to claim 12, wherein said color synthesizing means comprises a quadrangular prism formed by combining four triangular prisms. 28. The liquid crystal projector according to claim 12, wherein said color synthesizing means is composed of at least one quadrangular prism formed by combining two triangular prisms, and at least one dichroic mirror. . 29. The liquid crystal projector according to claim 12, wherein the plurality of tertiary light sources and the vicinity of the stop position of the projection lens are substantially conjugate. 30. The liquid crystal projector according to claim 12, wherein a part of the projection lens is disposed between the liquid crystal display device and the color synthesizing unit. 31. A light source unit, a first fly-eye lens for forming a plurality of secondary light sources from light from the light source unit, and a second fly-eye lens disposed near a position where the plurality of secondary light sources are formed. A fly-eye lens, light collecting means for superimposing light beams from the plurality of secondary light sources on a surface to be irradiated, a liquid crystal display device arranged on the surface to be irradiated, and projection for projecting an image based on the liquid crystal display device In a liquid crystal projector including a lens, the focal length of the light condensing means is f2, and the distance from the position where the secondary light source is formed to the front main plane position of the light condensing means is Of2. A liquid crystal projector satisfying Of2 / f2 <3/4. 32. A polarization converter comprising a λ / 2 plate near the second fly-eye lens for aligning random polarization vibration components in a predetermined direction.
LCD projector. 33. The liquid crystal device according to claim 32, wherein said polarization conversion means is formed by combining a plurality of light beam splitting elements based on a rod-shaped light beam splitting element having a polarized light beam splitting surface and a reflecting surface. projector. 34. The liquid crystal projector according to claim 33, wherein the polarized light beam splitting surfaces of the light beam splitting elements are arranged in parallel with each other. 35. The liquid crystal projector according to claim 33, wherein the polarized light beam splitting surface of the light beam splitting element is arranged symmetrically with respect to an optical axis of the illumination system including the light collecting means. 36. An optical axis from the light source section to the polarization conversion means and an optical axis from the light condensing means to the illuminated surface are shifted by a half of a pitch of the plurality of stacked light beam splitting elements. 35. The method according to claim 33, wherein
Or 35 liquid crystal projectors. 37. The liquid crystal projector according to claim 31, further comprising an optical path bending unit for bending an optical path between a position where the plurality of secondary light sources are formed and a front main plane position of the condensing unit. . 38. The liquid crystal projector according to claim 31, wherein the plurality of secondary light sources and a stop position of the projection lens have a substantially conjugate relationship. 39. A light source unit, secondary light source forming means for converging a light beam from the light source unit to form a secondary light source, and totally reflecting the light beam from the secondary light source inside to guide the light beam to an emission opening. A rod-shaped element, a relay lens group that takes in the light beam from the rod-shaped element and forms a plurality of tertiary light sources from the secondary light source, and a light-collecting device that superimposes the light beams from the plurality of tertiary light sources on an irradiated surface Means and a projection lens for projecting an image based on a liquid crystal display device disposed on the surface to be illuminated. A liquid crystal projector which satisfies 1/4 <Of2 / f2 <3/4, where Of2 is the distance to the front main plane position of the light collecting means. 40. The liquid crystal projector according to claim 39, further comprising: a polarization conversion unit having a λ / 2 plate for aligning a random polarization vibration component in a predetermined direction near a position where the tertiary light source is formed. . 41. The liquid crystal device according to claim 40, wherein said polarization conversion means is formed by combining a plurality of light beam splitting elements based on a rod-shaped light beam splitting element having a polarized light beam splitting surface and a reflecting surface. projector. 42. The liquid crystal projector according to claim 41, wherein said polarized light beam splitting surfaces of said light beam splitting element are arranged in parallel with each other. 43. The liquid crystal projector according to claim 41, wherein the polarized light beam splitting surface of the light beam splitting element is arranged symmetrically with respect to an optical axis of an illumination system including the light collecting means. 44. Between the light source unit and the rod-shaped element,
40. The liquid crystal projector according to claim 39, further comprising an optical path bending unit for bending an optical path. 45. The liquid crystal projector according to claim 44, wherein said optical path bending means is provided with a reflection film having a wavelength selection characteristic. 46. The liquid crystal projector according to claim 39, wherein a lens is disposed near an incident surface of said rod-shaped element. 47. The liquid crystal projector according to claim 46, wherein a lens surface on the light source side of a lens disposed near the incident surface of the rod-shaped element is a convex surface. 48. The emission surface of the rod-shaped element is held in contact with each other by a lens surface of a lens disposed closest to the light source unit in the relay lens group. 39 LCD projectors. 49. The liquid crystal projector according to claim 39, wherein an exit surface of said rod-shaped element is held in contact with a parallel flat plate. 50. When the length of the longitudinal section of the exit surface of the rod-shaped element is D and the length in the optical axis direction is L, 6.5 <L / D <9.0 is satisfied. 40. The liquid crystal projector according to claim 39. 51. At least one of the relay lens groups
The liquid crystal projector according to claim 39, wherein the lenses have an aspherical surface. 52. The optical axis from the light source section to the polarization conversion means and the optical axis from the light condensing means to the illuminated surface are only half the pitch of the plurality of stacked bar-shaped light beam splitting elements. 5. The method according to claim 4, wherein the position is shifted.
1, 42 or 43 liquid crystal projector. 53. The liquid crystal projector according to claim 39, further comprising an optical path bending unit that bends an optical path between a position where the plurality of tertiary light sources are formed and a front main plane position of the light collecting unit. . 54. The liquid crystal projector according to claim 39, wherein the plurality of tertiary light sources and the vicinity of the stop position of the projection lens are substantially conjugate. 55. A light source unit for emitting white light, secondary light source forming means for forming a plurality of secondary light sources from the light from the light source unit, and light beams from the plurality of secondary light sources on an irradiated surface. A light-collecting unit that overlaps the light-collecting unit, a color separating unit that separates a light beam passing through the light-collecting unit into a plurality of color lights, a liquid crystal display device that is disposed in an optical path, and a light-transmitting liquid crystal display device for each color light. In a liquid crystal projector comprising a color synthesizing means for synthesizing color lights and a projection lens for projecting an image of each color light through the color synthesizing means based on a liquid crystal display device, the focal length of the light condensing means is f2, 2 A liquid crystal projector which satisfies Ｏ <Of2 / f2 <３ when a distance from a position where a next light source is formed to a front main plane position of the light condensing unit is Of2. 56. The liquid crystal projector according to claim 55, further comprising: a polarization conversion unit provided near the plurality of secondary light sources with a λ / 2 plate for aligning a random polarization vibration component in a predetermined direction. 57. The liquid crystal device according to claim 56, wherein said polarization conversion means is formed by combining a plurality of light beam splitting elements based on a rod-shaped light beam splitting element having a polarized light beam splitting surface and a reflecting surface. projector. 58. The liquid crystal projector according to claim 57, wherein the polarized light beam splitting surfaces of the light beam splitting elements are arranged in parallel with each other. 59. The liquid crystal projector according to claim 57, wherein the polarized light beam splitting surface of the light beam splitting element is arranged symmetrically with respect to an optical axis of an illumination system including the light collecting means. 60. An optical axis from the light source section to the polarization conversion means and an optical axis from the light condensing means to the illuminated surface are shifted by a half of a pitch of the plurality of stacked light beam splitting elements. 57. The method according to claim 57, wherein
Or a liquid crystal projector of 59. 61. The liquid crystal projector according to claim 55, further comprising an optical path bending unit that bends an optical path between a position where the plurality of secondary light sources are formed and a front main plane position of the light collecting unit. . 62. The liquid crystal projector according to claim 55, wherein said color synthesizing means comprises a quadrangular prism formed by combining four triangular prisms. 63. The liquid crystal projector according to claim 55, wherein said color synthesizing means comprises at least one quadrangular prism formed by combining two triangular prisms, and at least one dichroic mirror. . 64. The liquid crystal projector according to claim 55, wherein said plurality of secondary light sources and a stop position of said projection lens are substantially conjugated. 65. The liquid crystal projector according to claim 55, wherein some lenses of said projection lens are arranged between said liquid crystal display device and said color synthesizing means. 66. The liquid crystal projector according to claim 55, wherein said secondary light source forming means comprises a solid rod lens. 67. A light source unit, secondary light source forming means for forming a plurality of secondary light sources from light from the light source unit, and the plurality of secondary light sources.
A liquid crystal projector comprising: a light condensing means for superimposing a light beam from a next light source on a surface to be illuminated; a liquid crystal display device disposed on the object to be illuminated; The focal length of the means is f2,
A liquid crystal projector characterized by satisfying 1/4 <Of2 / f2 <3/4 when a distance from a position where a next light source is formed to a front main plane position of the condensing unit is Of2. 68. The liquid crystal projector according to claim 67, further comprising: a polarization conversion unit provided near the plurality of secondary light sources and having a λ / 2 plate for aligning a random polarization vibration component in a predetermined direction. 69. The liquid crystal device according to claim 68, wherein said polarization conversion means is formed by combining a plurality of light beam splitting elements based on a rod-shaped light beam splitting element having a polarized light beam splitting surface and a reflecting surface. projector. 70. The liquid crystal projector according to claim 69, wherein said polarized light beam splitting surfaces of said light beam splitting element are arranged in parallel with each other. 71. The liquid crystal projector according to claim 69, wherein the polarized light beam splitting surface of the light beam splitting element is arranged symmetrically with respect to an optical axis of an illumination system including the light collecting means. 72. An optical axis from the light source section to the polarization conversion means and an optical axis from the light condensing means to the illuminated surface are shifted by a half of a pitch of the plurality of stacked light beam splitting elements. 70. The method according to claim 69, wherein:
Or 71 liquid crystal projector. 73. The liquid crystal projector according to claim 67, further comprising an optical path bending unit that bends an optical path between a position where the plurality of secondary light sources are formed and a front main plane position of the light collecting unit. . 74. The liquid crystal projector according to claim 67, wherein the plurality of secondary light sources and a stop position of the projection lens have a substantially conjugate relationship. 75. The liquid crystal projector according to claim 67, wherein said secondary light source forming means comprises a solid rod lens.