JP2610087B2 - Illumination optical system and projection type liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to three primary colors of white light, R (Red), G (Green), and B (Blue).
And an illumination optical system for uniformly illuminating an illuminated surface such as a liquid crystal panel or a transmissive film, and a projection type liquid crystal display device for enlarging and projecting an image of a liquid crystal light valve with a projection lens. About.

[0002]

2. Description of the Related Art A conventional illumination optical system is disclosed in Japanese Patent Publication No. 3-786.
As an illumination device used for a semiconductor exposure device such as an optical device for illumination No. 07 and a projection display device for projecting using a liquid crystal panel, a technical report of the Institute of Television Engineers of Japan, Showa 6,
"Full-color video projector using TFT-LCD" announced on August 5, 2001, and Technical Report of the Institute of Television Engineers of Japan 8
"High-definition liquid crystal projection display" announced on October 27, 1997.

[0003]

However, when the above-mentioned conventional illumination optical device is used, it is particularly effective for light requiring parallelism, but this method uses an elliptical reflecting mirror. Since the light is collected at the second focal point and the light is treated as a point light source, the light collection efficiency of the light source is extremely low. For example, an optical system that enlarges and projects an image is insufficient. In a video projector presented by the inventors at a conference in 1986, the distance to the irradiation surface of the illumination light was short, and the center of the irradiation surface was shadowed during color separation due to the thickness of the cross-type mirror. There are problems such as shading and uneven color due to different distances of the three colors to the irradiation surface after color separation.

Further, as a method of reducing such color unevenness, an irradiation method by a method in which the distance to an irradiation surface is substantially reduced by using a relay optical system as described in a 1989 paper has been devised. However, in the illumination optical system using the relay optical system, the performance can be exerted under the conditions close to the point where the light source is issued, that is, a point light source. However, in a lamp such as a metal halide lamp having an arc length of several millimeters, color unevenness occurs. Was difficult to reduce.

Further, regarding the illuminance ratio on the irradiation surface,
It became dominant due to the illuminance distribution diverging from the light condensing system, and could not be an effective means for making the illuminance distribution uniform such that the center of the irradiation surface was high and the periphery was dark.

In the case of a conventional projection type liquid crystal display device, the distance from the light source to the light valve surface differs for each color.
The illuminance distribution on the illuminated surface is different from each other, which causes color unevenness, and even if the distance to the illuminated surface is equal, in the case of metal halide lamp discharge, the center of the display area is affected by the difference in the excitation temperature of each halide metal. And the occurrence of color unevenness having different colors in the peripheral portion was remarkable.

Further, when a projection type display device in which more light is incident on a very small liquid crystal light valve (for example, a diagonal dimension of 1 to 2 inches), the arc length of the lamp is reduced. In the case of a metal halide lamp of about 5 mm, the size of the reflector is 80 mm to 10 mm.
A reflector having a diameter of 0 mm was required, so that it was difficult to condense the light in the periphery to a small light valve surface, and as a result, the projected image had a drawback such as darkness.

Also, 9: 1 such as a high-definition television is used.
Sufficient characteristics could not be obtained with respect to the illuminance ratio of the display screen in a landscape screen having an aspect ratio of 6.

An illumination optical system of the present invention and a projection type liquid crystal display device using the same are intended to solve the above-mentioned problems. A plurality of light sources are formed by lenses, and the light is separated into three primary colors of light by a cross dichroic mirror. Each of the color lights separated in three directions is arranged in a conjugate relationship with the first multi-lens lens. By irradiating a plurality of light sources onto the desired irradiation surface as integrated light by the multi-lens lens of the above, the irradiation surface of each of the three colors can provide an illumination optical system capable of reducing the color unevenness of the light source. To provide. Further, from a plurality of secondary light sources, three second light sources are used.
The present invention provides a bright and desired illuminance distribution by illuminating the irradiation surface with the multi-lens lens so that the optical axis is aligned or shifted with respect to the irradiation surface.

[0010]

According to a first aspect of the present invention, there is provided a light emitting device comprising: a light source; A first multi-lens lens forming a light source, and a cross dichroic mirror for color separating light from the first multi-lens lens
Comprising a chromatography, and the cross dichroic by dichroic mirror color separated plurality of second arranged to irradiate on each irradiation surface of the plurality of the illuminated object color lights multiview lens,
Each lens constituting the first multi-lens lens and the second lens
The lenses constituting the multi-lens are of the same size, and the lenses constituting the second multi-lens irradiate the light from the lens on the irradiation surface in a superimposed manner. In addition, a part of the optical axis is shifted from the center. The invention according to claim 2 provides an illumination optical system according to claim 1, and three liquid crystal light valves that modulate each light from three second multi-lens lenses in the illumination optical system.
A light combining means for combining the lights modulated by the three liquid crystal light valves and a projection lens for receiving the light from the light combining means. Claim 3
The invention of claim 1 reflects the light from two of the three second multi-lens lenses in the illumination optical system of claim 1 and the direction of the light from the remaining one, respectively. Reflective means for modulating each light from the three multi-lens lenses whose light directions coincide with each other; and inputting each light modulated by the three liquid crystal light valves. And two projection lenses.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows an embodiment of an illumination optical system according to the present invention.
(B) is a perspective view showing the configuration of the multi-lens lens in an easy-to-understand manner, and the main components will be described below.

FIG. 1A shows the configuration of an illumination optical system according to the present invention. A luminous flux radiated from a lamp 1 such as a halogen lamp, a xenon lamp, or a metal halide lamp is reflected by a parabolic reflector 2 and is substantially reflected therefrom. The light becomes parallel and enters the first multi-lens lens 3. The multi-lens lens is as shown in FIG. That is, the first multi-lens lens 3
And the three second multi-lens lenses 4 are a combination of a plurality of rectangularly cut lenses, and the position of the focal length a of each lens of the first multi-lens lens 3 is the second multi-lens lens. It is located at the apparent entrance pupil position of the ophthalmic lens 4 and forms an image there. The shape of the lens cut into a rectangle is similar to the shape of the irradiation surface. For example, if the irradiation surface is rectangular, a plurality of rectangular lenses cut into a rectangle are attached to each other. The optical axis (indicated by a dashed line in the figure) of the first multi-lens lens 3 is provided at the center of each rectangular lens, while the second multi-lens lens 4 is provided with a first multi-lens lens 4. The optical axis is shifted from the optical axis of the ophthalmic lens 3 and forms a so-called tilt optical system that differs depending on the amount of superposition of the optical axis on the irradiation surface.

The shapes of these multi-lens lenses are arranged so as to be inscribed or circumscribed within the rim diameter of the parabolic reflector 2 when viewed from the light emitting surface side of the light source. The cross dichroic mirror 5 is a color-selective mirror in which a dichroic mirror having a reflecting surface at 45 degrees to the light incident surface is formed in an X shape. For example, when white light is incident, R is the three primary colors of light. , G and B are color-separated in three directions. A second multi-lens 4 is arranged in each of these three directions.

FIGS. 2A and 2B illustrate a basic configuration of a multi-lens lens relating to the illumination optical system of the present invention. FIG. 2A is a configuration diagram, and FIG. It is a schematic diagram.

The light from the lamp 1 is reflected by the parabolic mirror 2 as substantially parallel light rays and enters the first multi-lens lens 3. Each lens of the first multi-lens 3 is arranged in a conjugate relationship with the second multi-lens 4, and the first multi-lens 3 has a focal length f1 = a and the first multi-lens 3 has a focal length f1 = a. Expression lens 3
The distance between the second multi-lens lens 4 and the second multi-lens lens 4 is set to be a, and guides light beams from a plurality of light sources to the entrance pupil position of the second multi-lens lens. These multi-lenses are shown in FIG.
As shown in (a), a rectangular lens divided into 20 is arranged so as to be inscribed in the circle of the parabolic mirror 2, and this arrangement is for swallowing more light from the lamp. .

The focal length f2 of the second multi-lens lens 4 is
Assuming that the distance between the second multi-lens lens 4 and the image generating means 7 such as a liquid crystal panel or a transparent film is b,

[0018]

F1 = 1 / {(1 / a) + (1 / b)}

The second multi-lens lens 4 is a tilted lens in which the optical axis of each lens is shifted. The second multi-lens lens 4 has a shape similar to the shape of the irradiation surface of the first multi-lens lens 3 to the image generating means 7. This is to superimpose and form an image of a light source block that is configured in advance. Therefore, even if the distance to the irradiation surface changes, the size of the irradiation surface can be kept constant by the focal length f2 of the second multi-lens lens. The projection lens 8 is a lens for projecting the image of the image generating means 7, and the lens preferably has an F-number having a swallow angle equal to or larger than the light divergence angle of the image generating means 7.

(Embodiment 2) FIGS. 3A and 3B are configuration diagrams of an optical system showing an embodiment of a projection type liquid crystal display device using an illumination optical system according to the present invention. FIG. ) Is a front view.

The light source comprises a lamp 1 such as a metal halide lamp or a xenon lamp, and a parabolic reflecting mirror 2, and is incident on a first multi-lens 3. The illumination optical system includes a first multi-lens 3, a cross dichroic mirror 5 arranged in a cross shape, and three second multi-lenses 4, and the light enters the first multi-lens 3. The white light becomes a light source which can be regarded as a plurality of light sources divided into a plurality of light sources. The light emitted from the plurality of light sources is color-separated by the cross dichroic mirror 5 into three primary colors of light, R, G, and B. Each color light is incident on a second multi-lens lens 4 having a plurality of entrance pupils arranged in a conjugate relationship with the first multi-view mirror 3. The light emitted from the second multi-lens lens 4 is R,
The light is guided to the liquid crystal light valve 14 at the image forming position of the second multi-lens lens 4 via the reflecting mirror 13 corresponding to each of the color lights of G and B. These second multi-lens lenses 4 are shown in FIG.
As shown in (1), a plurality of light sources of a first multi-lens lens 3 having a similar shape are superposed and irradiated on a rectangular irradiation surface having an aspect ratio of 16: 9, such as a high-definition television.

The liquid crystal light valve 14 forms an image by light modulation corresponding to each color, that is, a change in transmittance according to a signal voltage, and enters the light synthesizing means 15.

The light synthesizing means 15 is composed of a dichroic prism which is also used as a color synthesizing means shown in a conventional conference presentation. This prism is obtained by coating a dichroic film on the ridges of four triangular prisms. The light from the directions is uniaxially combined, and the image data modulated by the liquid crystal light valve is uniaxially combined. Enlarged projection is performed by the combined light projection lens 8.

FIG. 4 is a configuration diagram showing an embodiment in which the distance to the irradiation surface in the illumination optical system of the projection type liquid crystal display device is partially different.

The light emitted from the lamp 1 enters the cross dichroic mirror 5 via the first multi-lens lens 3. The incident light is, for example, 4 due to the reflection characteristics of the color selection surface.
Blue color light having a wavelength characteristic of 00 to 480 nm;
It is reflected and separated into red color light having a wavelength characteristic of 90 to 700 nm, and transmits the remaining light of 480 to 590 nm. The separated color lights of the three colors enter the second multi-lens lens 4. The distance from the second multi-lens lens 4 to the liquid crystal light valve 14 is such that the green color light is shorter than the red or blue color light, and therefore the focal length of the second multi-lens lens 4 is set to be shorter by green. Irradiate. In order to make the illuminance distribution on the irradiation surface the same for each color light, there are two types of distances between the second multi-lens lens 4 and the liquid crystal light valve surface, but the area of the irradiation surface does not change. The illuminance distribution is the same.

These uniformly illuminated color lights project an image modulated by a liquid crystal light valve onto a screen 16 by projection lenses provided for each of the three colors. The screen 16 in this case does not limit the present invention whether it is a reflection type or a transmission type.

[0027]

As described above, according to the present invention, the light from the light source which can be treated as a plurality of light sources by the first multi-lens divided into a plurality of light sources is used by the color selective reflection surfaces. The color is separated by a cross dichroic mirror crossing at right angles, and the color-separated color light is applied to an irradiation surface of a liquid crystal panel, a film, or the like by three second multi-lens lenses for guiding light in three directions. By forming an image in the form of a plurality of light source images of an expression lens, it is possible to uniformly guide light to an irradiation surface with less color unevenness, so that an efficient illumination optical system can be obtained.

By using this illumination optical system in a projection type liquid crystal display device, a bright display is possible, and the second multi-lens lens is adjusted to a swallow angle determined from the F-number value of the projection lens. Thus, a bright projection type liquid crystal display device can be provided.

[Brief description of the drawings]

FIG. 1 shows an embodiment of an illumination optical system according to the present invention.
2A is a configuration diagram of an illumination optical system, and FIG. 2B is a perspective view of a multi-lens used in the illumination optical system.

FIGS. 2A and 2B show a basic configuration of a multi-lens lens of the illumination optical system according to the present invention, wherein FIG. 2A is a configuration diagram, and FIG. .

3A and 3B show a configuration of an optical system of a projection display device configured using the illumination optical system of the present invention, wherein FIG. 3A is a plan view and FIG. 3B is a front view.

FIG. 4 is a configuration diagram showing an embodiment in which the distance to the irradiation surface in the illumination optical system of the projection display device of the present invention is partially different.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lamp 2 Parabolic reflector 3 First multi-lens lens 4 Polarization beam splitter 5 Cross dichroic mirror 7 Image generation means 8 Projection lens 13 Reflection mirror 14 Liquid crystal light valve 15 Light combining means 16 Screen

Continuation of front page (56) References JP-A-4-367836 (JP, A) JP-A-61-99118 (JP, A) JP-A-5-346557 (JP, A) JP-A-62-292912 (JP, A) JP-A-4-104241 (JP, A) JP-A-6-202063 (JP, A) JP-A-5-134230 (JP, A) JP-B-3-78607 (JP, B2) 1991 INTERNAL DISPLAY RESEARCH CONFERENCE P. 151-P. 154 A. H. J. VAN DEN BRANDT ET. AL. , "NEW PL USFACTORS IN AN LC D-PROJECTOR: HOMOGE NEOUS ILLUMINATION N, QUICK LAMP (RE-) START, RELIABLE CON SYNCTION, FULL RESOLUTION"

Claims (3)

(57) [Claims] The light emitted from the light source lamp has a light collecting property.
To form a plurality of secondary light sources
From the first multi-lens lens and the first multi-lens
For color separation of lightCross dichroic mirror
And theCross dichroic mirrorColor separated by
Each color light is projected onto each irradiation surface of a plurality of illuminated objects.
A plurality of second multi-lens lenses arranged in such a manner that each lens constituting the first multi-lens lens and the second
The lenses that make up the multi-view lens of
The respective lenses constituting the second multi-lens lens are
Light from the lens is superimposed on the irradiation surface and irradiated.
As shown in the figure, some of the optical axes are
Characteristic illumination optical system. 2. The illumination optical system according to claim 1, and said illumination optical system.
Modulate each light from the three second multi-lenses at
Three liquid crystal light valves and the three liquid crystal light valves
Light synthesizing means for synthesizing each light modulated by the light,
Having a projection lens for receiving light from the combining means
A projection type liquid crystal display device characterized by the above-mentioned. 3. An illumination optical system according to claim 1, and said illumination optical system.
From two of the three second multi-lenses at
Each light reflects and matches the direction of light from the other one
Reflecting means, and the three multi-view systems in which the directions of light coincide with each other
Three liquid crystal light valves that modulate each light from the lens
And each light modulated by the three liquid crystal light valves
Characterized by having three incident lenses for incidence
Projection type liquid crystal display device.