JPH06265887A - Projection type display device - Google Patents

Abstract

PURPOSE:To display a bright image of high quality with a uniform illuminance distribution without any color unevenness by using plural light sources, using a lighting device which has a uniform lighting optical element, and also arranging a field lens. CONSTITUTION:The light sources 101a and 101b are used and luminous flux reflected by a curved surface reflecting mirror 102 travels to the center part of a liquid crystal panel 109. The uniform lighting optical element 118 consists of a 1st lens plate 103 and a 2nd lens plate 104 and the respective lenses in the 2nd lens plate 104 forms images of the corresponding lenses in the 1st lens plate 103 in the display area 306 of the liquid crystal panel 109 one over another. At this time, the lighting luminous flux to the liquid crystal panel 109 is diverged light from the 2nd lens plate 104, so the field lens 108 is required to make parallel light incident on the liquid crystal panel 109. Thus, the main light beam is made incident on the entire surface of the liquid crystal panel 109 in a nearly parallel state and luminous flux transmitted through the liquid crystal panel 109 is made incident on a projection lens 116, and then enlarged and projected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a projection type display device for enlarging and displaying an image of a light valve for light flux modulation on a screen.

[0002]

2. Description of the Related Art A liquid crystal projector using a transmissive liquid crystal panel as a light valve is one of the projection type display devices, and has been put to practical use mainly for home use because of its small size and light weight. In this liquid crystal projector, uniformization of display color and display brightness has become a major issue. In a normal liquid crystal projector, for example, radiated light from a metal halide lamp is collimated by a parabolic reflector to directly illuminate the liquid crystal panel, so that color unevenness caused by uneven light emission of the lamp occurs on the display screen, and Since the center becomes considerably brighter than the peripheral portion, the display quality was inferior to that of a CRT direct-view image.

As one method for uniformly illuminating the liquid crystal panel, there is a method using an integrator which is generally used in an exposure machine or the like. In this integrator, two lens plates each having a plurality of rectangular lenses arranged in a matrix are arranged at a light source light emitting portion, and each light beam cross section cut out by the first lens plate is illuminated by the second lens plate. The image is superimposed and imaged on top. Illuminating the liquid crystal panel in this way makes the illuminance distribution extremely uniform,
Color unevenness is also eliminated. The specific method is described in detail in Japanese Patent Laid-Open No. 3-111806.

[0004]

However, in the prior art, since a single light source is used, nothing is displayed when the light source does not turn on for some reason such as life.

Further, because of the wavelength characteristic peculiar to the lamp,
In order to obtain desired color characteristics on the screen, some kind of color correction must be applied. For example, in a metal halide lamp, the red light is weak, and therefore the light flux of blue or green light must be attenuated in order to achieve white balance, so that the light utilization efficiency is reduced.

Further, generally, even if the power consumption is increased in order to increase the brightness, there is a problem that the light emitting portion becomes large, the light collecting efficiency is lowered, and the power consumption is not bright.

Therefore, the present invention solves such a problem, and an object thereof is to provide a lighting device of a liquid crystal projector with a plurality of light sources and use a uniform lighting optical element such as the integrator described above. It is an object of the present invention to provide a projection display device in which the brightness distribution of illumination is extremely uniform, there is no unevenness in brightness or color on the display screen, the light utilization efficiency is high, and the brightness is good and the white balance is good.

[0008]

A projection type display device of the present invention provides an illuminating device which emits light containing color components of three primary colors and an optical image which modulates the output light of the illuminating device and corresponds to video information. In a projection display device comprising a light valve to be formed and a projection lens which receives output light from the light valve and projects an optical image of the light valve onto a screen,
The illuminating device is composed of a plurality of light sources, and at least one lens plate having a configuration in which a plurality of lenses are arranged in a plane perpendicular to the main axis of the output light of the illuminating device, between the illuminating device and the previous light valve And a field lens for converging a divergent light beam from the lens plate on the projection lens, on the light beam incident side of the light valve.

The projection type display device of the present invention includes an illuminating device which emits light containing color components of three primary colors, a light valve which modulates output light of the illuminating device and forms an optical image according to image information, In a projection display device including a projection lens that receives output light from the light valve and projects an optical image of the light valve onto a screen, the illumination device has at least one light source and the same randomly polarized light source. At least one lens plate, which is composed of a polarization conversion element that converts the light into polarized light, is provided between the lighting device and the light valve in the previous stage and in which a plurality of lenses are arranged in a plane perpendicular to the main axis of the output light of the lighting device. A single lens is arranged, and a field lens for substantially collimating the divergent light beam from the lens plate is arranged on the light beam incident side of the light valve.

The projection display device of the present invention is characterized in that the focal length of the field lens is made substantially equal to the optical path length between the lens plate and the field lens.

The projection type display device of the present invention is characterized in that a plurality of light sources of the illumination device have different spectral characteristics.

The projection display device of the present invention is characterized in that at least one of the light sources of the illuminating device is a light source capable of instantaneous lighting.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A projection display device according to the present invention will be described in detail below with reference to the drawings.

(Embodiment 1) FIGS. 1 and 2 are views showing an optical configuration of the present invention. As the light sources 101a and 101b, those having a light emitting portion close to a point such as a halogen lamp, a metal halide lamp, and a xenon lamp are used.
The luminous flux emitted from the light emitting portion is reflected by the curved reflecting mirror 102.

In order to increase the brightness with a single light source, it is sufficient to increase the power of the light source, but since the light emitting portion also increases in accordance with the normal power, the light collection efficiency decreases and the light does not become bright in proportion to the power consumption. . According to the invention, a plurality of light sources 1
Since 01a and 101b are used, the power can be increased while keeping the light emitting unit small, and thus brightness proportional to power consumption can be realized.

For example, if the power is doubled with a single light source and the size of the light emitting portion is also doubled, the light collection efficiency is reduced to about half, and the brightness on the screen remains almost unchanged. However, if two light sources with the same size of the light emitting section are used, the light collection efficiency remains the same and the brightness is doubled.

Even if one of them does not light up,
Since the display is performed by being illuminated by the other light source, the viewer does not feel uncomfortable and there is no need to interrupt the display for replacing the light source. Although two light sources are used in this embodiment, two or more light sources may be used.

In FIG. 1, an elliptical surface is used as the curved surface shape of the curved reflecting mirror 102, and the first focus thereof is the light source 101a,
The second focal point corresponds to the light emitting portion of the liquid crystal panel 101b.
Since it is at the center position of 9, the light flux reflected by the curved reflecting mirror 102 is directed to the center of the liquid crystal panel 109.

The uniform illumination optical element 118 is the first lens plate 1.
03 and the second lens plate 104, the second lens plate 1
The size of 04 is smaller than the size of the first lens plate 103. The centers of the lenses in the first lens plate 103, the centers of the lenses in the second lens plate 104 that correspond one-to-one, and the centers of the liquid crystal panel 109 are aligned in a substantially straight line.

Therefore, each lens in the second lens plate 104 forms an image of the corresponding lens in the first lens plate 103 on the display area 306 of the liquid crystal panel 109 in an overlapping manner. The apparent light source position seen from the liquid crystal panel 109 coincides with the position of the second lens plate 104.

For example, the display area 306 of the liquid crystal panel 109
The principal ray 302 of the light beam incident on the end of the second lens plate 104 coincides with the line segment connecting the center of the second lens plate 104 and the end of the display region 306.

That is, since the illumination light flux to the liquid crystal panel 109 is divergent light from the second lens plate 104, the field lens 108 is required to make the parallel light incident on the liquid crystal panel 109.

The focal length of the field lens 108 is made substantially equal to the distance between the second lens plate 104 and the field lens 108, and in the figure, it is a plano-convex lens with the convex surface facing the liquid crystal panel 109 side. The two-lens plate 104 may be directed, or a biconvex lens or a Fresnel lens may be used. The principal ray of the light flux passing through the end of the liquid crystal panel 109 is parallel to the optical axis 305 of the entire illumination system.

In this way, the principal ray is incident on the entire surface of the liquid crystal panel 109 substantially in parallel, so that the influence of the clear viewing direction is eliminated and a uniform contrast ratio can be obtained over the entire surface.

The light flux transmitted through the liquid crystal panel 109 enters the projection lens 116 and is enlarged and projected. Projection lens 11
If the lens 6 is a telecentric lens, uniform display of brightness, color, and contrast ratio can be obtained.

In FIG. 2, a parabolic surface is used as the curved surface shape of the curved reflecting mirror 102, and the light emitting portions of the light sources 101a and 101b coincide with the focal point of the parabolic surface, so that the reflecting surface is reflected by the curved reflecting mirror 102. The formed light flux becomes a light flux substantially parallel to the optical axis 305 of the illumination system.

The uniform illumination optical element 118 is the first lens plate 1.
03, the second lens plate 104, and the third lens 301, the first lens plate 103 and the second lens plate 104 have the same size, and the same lens plate is used. Second
Since each lens in the lens plate 104 forms an image of the corresponding lens in the first lens plate 103 at infinity, in this case, the third lens 301 is further added to form an image that should be infinity. Are formed on the display area 306 of the liquid crystal panel 109. The focal length of the third lens 301 is substantially equal to the distance between the third lens 301 and the liquid crystal panel 109. The second lens plate 104 and the third lens 301 may be integrally formed. Even with such a configuration of the uniform illumination optical element, the field lens 108 is arranged on the light flux incident side of the liquid crystal panel 109, basically the same as in the case of FIG.

The most suitable one for the uniform illumination optical element 118 shown in FIGS. 1 and 2 is an integrator generally used in an exposure machine. FIG. 3 shows a basic configuration when used in a projection display device.

The first lens plate 103 includes a plurality of rectangular lenses 201 in a matrix, and the second lens plate 104 includes a plurality of rectangular lenses 202 in a matrix. The shape of each rectangular lens 201 of the first lens plate 103 is similar to the shape of the liquid crystal panel to be illuminated, and the image of each rectangular lens 201 is displayed on the liquid crystal panel by the corresponding rectangular lens 202 of the second lens plate 104. Since the image is superimposed and formed on the liquid crystal panel, the liquid crystal panel is illuminated with uniform illuminance with almost no color unevenness.

First lens plate 103 and second lens plate 104
Need not be separated, and the rectangular lenses 201,
If the number of 202 is increased and the lens plates 103 and 104 are brought closer to each other, they can be integrated into one lens plate. As for the number, four or more rectangular lenses 201, 202
By using, it becomes possible to perform sufficient uniform illumination.

The second lens plate 104 does not necessarily have to be formed of a rectangular lens, and for example, hexagonal lenses may be arranged. Various other arrangements and methods of configuring a plurality of lenses included in each lens plate are conceivable, and details are described in the above-mentioned Japanese Patent Laid-Open Publication.

(Embodiment 2) FIG. 4A is a block diagram showing another embodiment of the present invention. A light flux emitted from an illumination device configured by the light sources 101a and 101b and the curved reflecting mirror 102 is incident on the polarization conversion element 401, and polarized light whose polarization planes are aligned is incident on the uniform illumination optical element 118.

Then, as in the first embodiment, the liquid crystal panel 109 is uniformly illuminated by passing through the field lens 108, and the modulated image is enlarged and projected by the projection lens 116.

Here, the liquid crystal panel 109 performs display in a mode that requires the polarizer 405. Originally, half of the incident light is eliminated by the polarizer 405, so that the brightness is halved, but since the polarization plane is aligned by the polarization conversion element 401, the polarization plane of the polarizer 405 is aligned. , The efficiency is doubled and the brightness is doubled. Further, since the polarizer 405 does not absorb light, deterioration due to heat is prevented and reliability is improved.

FIG. 4B shows an example of the structure of the polarization conversion element 401. It is composed of a polarization separation element 402, a reflection mirror 403, and a polarization rotation element 404.

A light beam 406 incident on the polarization separation element 402
Is random polarized light, which is separated into P polarized light 407 and S polarized light 408, and P polarized light 407 is transmitted. The S-polarized light 408 is reflected, further reflected by the reflection mirror 403, and enters the polarization rotation element 404. A 1/2 wavelength plate is typically used as the polarization conversion element 404, but any one that rotates the polarization plane by 90 degrees, such as a mica wavelength plate or a TN liquid crystal plate, may be used. The light passing through the polarization rotation element 404 is P
It is emitted as polarized light 407.

Generally, the polarization separation element 402 and the polarization rotation element 404 do not have flat wavelength characteristics, and the spectral characteristics of the emitted light beams are different. If they are simply combined, color unevenness will occur on the screen. However, in the present invention, the uniform illumination optical element 118 enables uniform and color-uniform illumination.

A bright projection display device having no color unevenness or illuminance unevenness can be achieved even with a single light source. Further, by using a plurality of light sources, the brightness can be increased and the effect of the above-described embodiment can be exhibited.

(Embodiment 3) The light source 101 of the above embodiment
A case where lamps having different spectral characteristics are used for a and 101b will be described.

In general, in order to obtain a desired chromaticity and white balance on a screen with a single light source, it is common to attenuate the strong intensity color light of the three primary colors of light to match the weak intensity color light. Is. In addition, light sources with different spectral characteristics,
Since the size of the light emitting portion is different and the light condensing characteristics are also different, even if they are combined, color unevenness occurs.

In the present invention, a metal halide lamp having strong blue light and green light and a halogen lamp having strong red light are combined. Furthermore, by using the uniform illumination optical element 118, it is possible to obtain a display having excellent white balance and no color unevenness.

A metal halide lamp was used for one light source 101a, and a halogen lamp was used for the other light source 101b. FIG. 5 shows the spectral characteristics of the metal halide lamp and the halogen lamp. The dotted line is the metal halide lamp, the chain line is the halogen lamp, and the solid line is the spectral characteristics when combined.

By thus combining the light sources having different spectral characteristics, it was possible to efficiently obtain the desired chromaticity and white balance on the screen without attenuating any color light.

Although a metal halide lamp having a high luminous efficiency is mainly used as a light source, it has been a problem that it takes time to stabilize after lighting. It is possible to instantly turn on halogen lamps and xenon lamps and instantly turn them on again, but the luminous efficiency is low. Therefore, by using a metal halide lamp having a high luminous efficiency and combining at least one light source capable of instantaneous lighting or relighting, efficient instantaneous display can be achieved.

(Embodiment 4) Another embodiment of the projection type display device of the present invention is shown in FIG. The basic configuration is similar to that of the first embodiment.

Light sources 101a and 101b and curved reflecting mirror 10
The luminous flux emitted from the illuminating device constituted by 2 passes through the uniform illumination optical element 118 constituted by the first lens plate 103 and the second lens plate 104, and is reflected by the blue-green reflection dichroic mirror 105 and the blue reflection dichroic mirror 106. , Enters the color separation optical system including the reflecting mirror 107.

The blue light contained in the white light from the light sources 101a and 101b is reflected by the two dichroic mirrors of the color separation optical system, and the red light is transmitted by the blue-green reflection dichroic mirror 105 and then reflected by the reflecting mirror 107. To be done. The green light is reflected by the blue-green reflection dichroic mirror 105 and then passes through the blue reflection dichroic mirror 106.

The respective color lights have the same optical path distance from the uniform illumination optical element 118 to the liquid crystal panel 109.

Next, each color light enters the field lenses 108a, 108b, 108c, respectively, and the divergent light flux from the uniform illumination optical element 118 is collimated. The collimated color lights are respectively reflected by the field lenses 108a, 1a.
Liquid crystal panel 109 placed immediately after 08b and 108c
Image information corresponding to each color light is added by being incident on a, 109b, and 109c and modulated.

Liquid crystal panels 109a, 109b, 109c
The respective color lights modulated by are then incident on a color combining optical system including a blue reflection dichroic mirror 110, a blue-red reflection dichroic mirror 111, and a reflection mirror 107. Blue light is reflected and red light is transmitted to the blue reflection dichroic mirror 110. Further, since the green light is transmitted to the blue-red reflection dichroic mirror 111 and the red light and the blue light are reflected, all the color lights are combined on the same optical axis.

The optical image thus synthesized is projected onto the projection lens 1
It is projected and displayed on the screen 117 by 16. As the projection lens 116, one close to a telecentric system is used.

Although the polarization conversion element is not omitted in FIG. 6, it is clear that the effect of the above-described second embodiment can be obtained if it is inserted between the illumination device and the uniform illumination optical element. is there.

Although the illumination optical system is arranged on the left side of the paper surface in FIG. 6, it may be arranged below the paper surface to replace the blue-green reflection dichroic mirror 105 with a red reflection dichroic mirror. Also, the two lens plates 10
Since a reflecting mirror can be arranged between 3, 104 to bend the optical path by 90 degrees, there is a considerable degree of freedom in the arrangement of the lighting device. Furthermore, the order in which each color of light is separated and combined is completely free by selecting the dichroic mirror.The light of the three primary colors is separated into three colors, modulated by the liquid crystal panel, and then the three colors are combined. It is compatible with all liquid crystal projectors that project images.

[0054]

As described above, according to the present invention, a plurality of light sources are used in an optical system of a liquid crystal projector,
By using the illuminating device having the uniform illuminating optical element and further disposing the field lens, it is possible to realize a projection display device which displays a brighter and higher-quality image than the conventional one without unevenness in color with a uniform illuminance distribution.

Further, since a plurality of light sources are used, it is possible to display even if one light source is not turned on, and by combining light sources having different spectral characteristics, a projection type display with excellent color characteristics can be obtained efficiently. A device can be provided.

By combining at least one light source such as a halogen lamp that can be instantly turned on, display can be performed at the moment when the power of the device is turned on.

Further, by using the polarization conversion element, it is possible to realize a projection type display device which is free from unevenness in color and unevenness in illuminance and has a dramatically improved brightness.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a projection display device of the present invention.

FIG. 2 is a configuration diagram of another embodiment of the projection display device of the present invention.

FIG. 3 is a configuration diagram of a uniform illumination optical element used in the projection display device of the present invention.

FIG. 4A is a configuration diagram of another embodiment of the projection display device of the present invention. FIG. 3B is a configuration diagram of a polarization conversion element used in the projection display device of the present invention.

FIG. 5 is a spectral characteristic diagram of a light source in an embodiment of the projection display device of the present invention.

FIG. 6 is a configuration diagram of another embodiment of the projection display device of the present invention.

[Explanation of symbols]

 101a, b Light source 102 Curved mirror 103 First lens plate 104 Second lens plate 108 Field lens 109 Liquid crystal panel 116 Projection lens 118 Uniform illumination optical element 201, 202 Rectangular lens 301 Third lens plate 401 Polarization conversion element 405 Polarizer

Claims (5)

[Claims] 1. A lighting device that emits light containing color components of three primary colors, a light valve that modulates output light of the lighting device to form an optical image according to image information, and output light from the light valve. In the projection display device including a projection lens that receives the optical image of the light valve on a screen, the illumination device includes a plurality of light sources, and a plurality of lenses are provided between the illumination device and the previous light valve. A uniform illuminating optical element including at least one lens plate having a structure in which is arranged in a plane perpendicular to the main axis of the output light of the illuminating device is arranged, and a divergent light beam from the lens plate is provided on a light beam incident side of the light valve. And a field lens for condensing the light on the projection lens. 2. An illumination device that emits light containing color components of three primary colors, a light valve that modulates the output light of the illumination device to form an optical image according to image information, and an output light from the light valve. In a projection display device including a projection lens that receives the optical image of the light valve on a screen, the illumination device includes at least one light source and polarization conversion that converts random polarization of the light source into the same polarized light. At least one lens plate having a plurality of lenses arranged in a plane perpendicular to the main axis of the output light of the illuminating device is arranged between the illuminating device and the light valve of the previous period. A projection type display device is provided with a field lens for substantially collimating the divergent light flux from the lens plate on the light flux incidence side. 3. The projection display device according to claim 1, wherein the focal length of the field lens is substantially equal to the optical path length between the lens plate and the field lens. 4. The projection display device according to claim 1, wherein a plurality of light sources of the lighting device have different spectral characteristics. 5. The projection display device according to claim 1, wherein at least one of the light sources of the lighting device is a light source that can be instantly turned on.