JP2001281760A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection type display device which uses plural solid- state light sources as illumination light sources, is high in light utilization efficiency, and makes it possible to obtain bright and high-grade projected videos. SOLUTION: This device has the plural solid-state light sources 201 arranged in a matrix form and an illumination system which is composed of beam- condensing optical system 202 and polarized light conversion optical system 203 corresponding to the light emitting points of the solid-state light sources and generates RGB light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a projection display device for projecting and displaying an image displayed on a two-dimensional light modulator, and more particularly to a projection display device using a liquid crystal light valve.

[0002]

2. Description of the Related Art A light valve type liquid crystal projector using a liquid crystal display element is widely used. This liquid crystal projector uses a so-called TN (Twisted Nematic) liquid crystal mode or an ECB (Electrically Controlled Birefringence) mode to polarize light. An image is formed by controlling the state. Using a thin film transistor or a transistor on a Si semiconductor substrate as a driving element, a fine image is formed as a transmission type or reflection type liquid crystal light valve.

[0003] By the way, such a light-bulb type projection display device requires a projection light source. In the prior art, a high-intensity discharge lamp such as a high-pressure mercury lamp or a metal halide lamp is generally used as the light source. Have been.

Further, a projection type display device using a solid light source such as a laser diode as a projection light source as disclosed in Japanese Patent Application Laid-Open Nos. 10-293545 and 11-65477 has been devised. However, those devices make the light source light incident on the light valve as it is.

[0005]

However, when a high-intensity discharge lamp such as a metal halide lamp or a xenon lamp is used as a light source as in the prior art, the light-collecting efficiency of the light source is poor. On the other hand, when a solid-state light source is used, There is a problem in that energy cannot be used because the polarized light cannot be used effectively.

In general, such a projection type display device requires a light source of three primary colors for color display. However, since a high-intensity discharge lamp is a white light source, color separation for separating light into three primary colors by a dichroic mirror or the like. An illumination optical system is required, and an air cooling device for heat dissipation is also required, which has been a bottleneck in downsizing the device.

On the other hand, solid-state light sources such as semiconductor lasers and light-emitting diodes have lower outputs than high-intensity discharge lamps, and cannot be said to be sufficient for use as a single light source.

SUMMARY OF THE INVENTION An object of the present invention is to provide a small-sized projection type display device which is bright by controlling a plurality of solid-state light sources and the polarization of the light from the light sources, has no unevenness in the light amount.

[0009]

In order to achieve the above object, the invention according to claim 1 comprises: an illumination system for generating at least red light, green light, and blue light; In a two-dimensional light modulator that modulates light in accordance with image information and a projection display device that projects modulated light from the two-dimensional light modulator, the illumination system includes a plurality of solid-state elements arranged in a matrix. A light source, a condensing optical system for condensing light from the solid-state light source, and a polarization conversion optical system for polarizing light from the condensing optical system to the two-dimensional light modulator. I do. According to this, the size of the illumination optical system can be remarkably reduced, and since the light emitting point of the light source is small, ideal light control can be performed, and loss of the light amount can be suppressed to a small value.

The invention according to claim 2 is characterized in that the plurality of solid-state light sources are constituted by a plurality of light emitting diodes. According to this, light with a narrow wavelength band and high color purity can be obtained, so that images and videos with a wide color reproduction range can be obtained.

Further, in the invention according to claim 3, the polarization conversion optical system is configured such that a polarization beam splitter for separating incident light into P-polarized light and S-polarized light and one of the P-polarized light and the S-polarized light is polarized by 90 degrees. It comprises a rotating half-wave plate and a reflecting mirror prism that bends the traveling direction of light. According to this, polarized light can be effectively used for projection without waste.

According to a fourth aspect of the present invention, the condensing optical system comprises a condensing lens array having a positive power, and a focal length of the condensing optical system is defined by a position of a polarization beam splitter of the polarization conversion optical system and a light emitting point. The position is set to be substantially conjugate. According to this, the light from the light source can be effectively introduced into the polarization conversion system.

Further, the invention according to claim 5 is characterized in that a mounting area of the light source array including the plurality of solid-state light sources is larger than a light receiving area of the two-dimensional spatial light modulator.
According to this, it is possible to reduce a component deviating from the entrance pupil of the projection lens.

The invention according to claim 6 is characterized in that the number of light sources corresponding to red light, green light, and blue light of the light source array composed of the plurality of solid-state light sources is not the same. According to this, a projected image with good color balance can be obtained.

Further, the invention according to claim 7 is characterized in that an illumination lens for multiplexing an image of light near the condensing optical system on the two-dimensional spatial light modulator is provided. According to this, it is possible to provide uniform illumination to the two-dimensional spatial light modulator.

The invention according to claim 8 is an illumination system for generating at least red light, green light and blue light, and a two-dimensional light for modulating each of the red light, green light and blue light according to image information. A modulator and a projection display device that projects modulated light from the two-dimensional light modulator, wherein the illumination system includes a plurality of solid-state light sources arranged in a matrix and a plurality of light-emitting points of the solid-state light sources. A condensing optical system arranged so as to project onto one lens of a condensing lens array in which a plurality of lenses are formed, and polarization conversion optics for polarizing light from the condensing optical system to the two-dimensional light modulator It is characterized by being composed of a system. According to this, it is possible to project a larger amount of light.

Further, according to a ninth aspect of the present invention, there is provided an illumination system that generates at least red light, green light, and blue light, and modulates each of the red light, green light, and blue light according to image information.
In a projection display device that projects modulated light from the two-dimensional light modulator and the two-dimensional light modulator, the illumination system includes:
A plurality of solid-state light sources arranged in a line, a condensing optical system arranged to project the linear light-emitting points of the solid-state light source to one lens of a cylindrical lens array, and light from the condensing optical system. It is characterized by comprising a polarization conversion optical system for polarizing the two-dimensional light modulator. According to this, a simple condenser lens system can be configured.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a basic configuration diagram of an optical system of a projection display according to a first embodiment of the present invention. Red light (R light), green light (G light), blue light (B light) with two dichroic coatings with different visible regions
Around the dichroic prism 101 that synthesizes
Three two-dimensional spatial light modulators 102, 103, and 104 for red (R), green (G), and blue (B) are arranged on the three surfaces. The projection lens 105 is arranged on the remaining surface. These two-dimensional spatial light modulators 102, 103, 10
For four, illumination systems 106, 107, and 108 comprising solid-state light sources of corresponding colors are provided.

The two-dimensional spatial light modulator 102 used here,
Reference numerals 103 and 104 denote devices for modulating the transmittance of incident light according to image information of each color. For example, a transmission type liquid crystal display element is typical, and specifically, a liquid crystal display element provided with a thin film transistor (TFT) for each pixel, a so-called active matrix type TN (Twisted Nematic) liquid crystal display element is generally used. It is. The two-dimensional spatial light modulator used in this embodiment is a polysilicon TFT-LCD.
It is. The principle of operation is to control the light transmittance by controlling the electro-optic effect of the liquid crystal, in particular, the polarization state by the electric field.

Next, when an image corresponding to each RGB is formed on each of the two-dimensional spatial light modulators 102, 103 and 104, these are synthesized by a dichroic prism 101 and formed on a screen (not shown) by a projection lens 105. Projected. Thus, a color image is reproduced.

FIG. 2 is a sectional view of the illumination system of the projection display device of the present invention. In order to simplify the description, only one color is taken out. Reference numeral 201 denotes a solid-state light source, specifically, a light-emitting diode. And the solid-state light source 201
A plurality, for example, 16 light sources are arranged in a matrix on a substrate 209 made of alumina ceramic. Light from the solid-state light source 201 is condensed by a condensing optical system 202. The light collecting optical system 202 is a lens array having a positive refractive power, for example, a light collecting lens array including a convex lens.

The light condensed by the condensing optical system 202 enters the polarization conversion optical system 203. The polarization conversion optical system includes a polarization beam splitter 204 and a half-wave plate 205. After splitting incident light into P and S polarized light, one of the polarization components is rotated by 90 ° by the half-wave plate 205. When either the P-polarized light or the S-polarized light separated in this way is reflected by the reflecting mirror prism 206 in the same direction as the traveling direction of the light, light having the same polarization can be generated effectively. In this case, the polarization splitting film of the polarization beam splitter 204 needs to have polarization selectivity only in the emission spectrum region of the light emitting diode, so that a narrow band design is sufficient. Further, in the present embodiment, the polarization beam splitter 204, the reflection mirror prism 206, and the half-wave plate 205
01 and corresponding positions correspond to each other and are arrayed. Each lens of the condensing optical system 202 corresponds to a light emitting point of the light emitting diode 201 which is a solid light source.

The focal length of the condenser optical system 202 is set so that the position of the polarization beam splitter 204 of the polarization conversion optical system 203 and the position of the light emitting point of the solid-state light source 201 are substantially conjugate. By doing so, almost all of the light from the solid-state light source 201 can be made incident on the polarization beam splitter 204. In the case of FIG. 2, the polarizing beam splitter 204, the reflecting mirror prism 206, the half-wave plate 20
5 are linearly accumulated in a direction perpendicular to the paper surface of FIG. This is because simpler manufacturing is possible than an individual array.

Further, an image in the vicinity of the condensing optical system 202 is, for example, a two-dimensional spatial light modulator 2 of a polysilicon TFT-LCD.
Illumination lens array 210 to form multiple images at 08
An illumination lens 207 is designed. In addition, the condensing optical system 202 has a configuration in which a plurality of rectangular single lenses similar to the display unit of the two-dimensional optical modulator 208 are arranged in a matrix. With the above configuration, uniform illumination can be given to the two-dimensional spatial light modulator 208. In FIG. 2, light rays are described for one central condensing lens of the condensing optical system 202. However, light passing through the other condensing lenses is of course similarly applied to the two-dimensional spatial light modulator 20.
8 is focused on the display unit.

The light-emitting diodes as the solid-state light sources 201 are mounted in a matrix on an alumina ceramic substrate 209 with a heat sink.

The mounting area of the light emitting diode arrays arranged in a matrix is formed to be larger than the light receiving area of the two-dimensional spatial light modulator 208. This condenses the light source light on the entrance pupil of the projection lens and reduces a component deviating from the entrance pupil of the projection lens caused by a shift of the optical axis between the polarized light transmitted through the polarization conversion optical system 203 and the polarized light whose polarization plane has been rotated. That's why. By doing so, a bright projected image can be obtained without using a large-diameter projection lens.

For the purpose of color balance, the number of light emitting diodes mounted on the light emitting diode array is not the same, but four red light emitting diodes of 2 × 2 and two green light emitting diodes are used.
It is also possible to adjust the number of blue light-emitting diodes to four (× 2) and nine (3 × 3) light-emitting diodes.

As described above, according to the present embodiment, since the spectral width of each of the RGB colors of the solid-state light source 201 is narrower than that of the illumination light color-separated by a conventional dichroic mirror or the like, the dichroic prism for synthesis is used. 10
There is an advantage that the three primary colors can be sufficiently synthesized even if the wavelength selection characteristic of the first coating is not steep.

Next, a modification of the embodiment of the present invention will be described. This modification is a case where a larger amount of light is required as compared with the above-described embodiment. That is, when a larger amount of light is required, it is necessary to integrate many solid-state light sources 301 as shown in FIG. As a result, the solid state light source 30
The light emitting points are too close to each other. However, in this case, as shown in FIG. 3, a plurality of solid-state light sources 301 are made to correspond to one lens of the condensing optical system 302 so as to irradiate the position of one polarization beam splitter 304. This allows a large amount of light to be required.

Although the solid-state light source 301 is formed as a matrix array, the present invention is not limited to this. For example, as shown in FIG.
1 is formed in a line shape, and a cylindrical lens array 4 is formed.
02 may be a condensing lens array, and the light may be condensed linearly on the polarization conversion optical system 403. Note that reference numeral 404 denotes an illumination lens.

[0031]

As described above, the projection type display device of the present invention does not need to separate the light source light into RGB as in the conventional liquid crystal projection type display device, and the size of the illumination optical system can be remarkably reduced. Since the light emitting point of the light source is small, ideal light control is possible, and the loss of light quantity can be suppressed to a small value. Further, the efficiency of the polarization conversion system is improved, and the light from the light source can be effectively used for projection without waste. If a plurality of light sources are arrayed as in the present application in order to increase the light output of the projected image, the load per element can be reduced and the heat generation can be dispersed, which has the effect of improving the reliability of the light source . Further, the cooling system, which was indispensable for the light source, can be simplified. Since light from a plurality of solid-state light sources can be combined and used, a projection image with sufficient brightness can be easily obtained. Further, according to the present invention, even if the light source varies or even one of the light sources fails, the function of the projection display device is not lost. The light utilization efficiency is high, and a bright projected image can be obtained. Furthermore, according to the present invention, since illumination with uniform illuminance can be given to the two-dimensional spatial light modulator, it is possible to obtain a high-definition projected image without uneven brightness. In addition, since the solid-state light source can obtain light with high color purity in a narrow wavelength band, according to the present invention, the color reproduction range is wider than when a white light source according to the related art is used, and as a result, a sufficiently high color reproduction range is obtained. A high quality projected image can be obtained.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of an optical system of a projection display according to an embodiment of the present invention.

FIG. 2 is a sectional view of an illumination system of the projection display device according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view of an illumination system including a plurality of light emitting points according to the embodiment of the present invention.

FIG. 4 is a perspective view of an illumination system of the linear solid-state light source array according to the embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 101 dichroic prism 102, 103, 104 two-dimensional spatial light modulator 105 projection lens 106, 107, 108 illumination system composed of solid light sources of R, G, B colors 201 solid light source 202 condensing optical system 203 polarization conversion optical system 204 Polarizing beam splitter 205 1/2 wavelength plate 206 Reflecting mirror prism 301 Plural light emitting points 302 Condensing lens array 401 Linear solid light source array 402 Cylindrical lens array

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H04N 9/31 H04N 9/31 BF term (Reference) 2H088 EA14 EA68 HA08 HA13 HA18 HA20 HA24 HA25 HA28 JA05 MA06 MA20 2H091 FA10X FA10Z FA11X FA11Z FA14Z FA21Z FA26X FA26Z FA41Z FA45Z LA15 LA16 MA07 5C060 BA04 BA08 BC05 EA00 GA01 GB02 GB06 HC00 HC01 HC25 HD07 JB06 5G435 AA03 AA04 AA18 BB12 BB15 BB17 CC09 CC12 DD05 EE26 GG05 GG25 GG07 GG07 GG05 GG07 GG05 GG07 GG05 GG07 GG25 GG05 GG07 GG07 GG07 GG05 GG07 GG07 GG07 GG05 GG07 GG25 GG25 GG25 GG05 GG25 GG25 GG25 GG25 GG25 GG15 GG25 GG15 GG07 GG25 GG25 GG25 GG25 GG15 GG25

Claims (9)

[Claims] 1. An illumination system that generates at least red light, green light, and blue light, a two-dimensional light modulator that modulates each of the red light, green light, and blue light according to image information, and the two-dimensional light. In a projection display device that projects modulated light from a modulator, the illumination system includes a plurality of solid-state light sources arranged in a matrix, a light-collecting optical system that collects light from the solid-state light sources, A projection display device comprising a polarization conversion optical system that polarizes light from a condensing optical system to the two-dimensional light modulator. 2. The projection type display device according to claim 1, wherein said plurality of solid-state light sources are constituted by a plurality of light-emitting diodes. 3. The polarization conversion optical system converts incident light into P-polarized light,
A polarizing beam splitter for separating into S-polarized light and the P-polarized light,
1/2 of rotating one of the S-polarized light by 90 degrees
2. The projection type display device according to claim 1, comprising a wave plate and a reflection mirror prism for bending a traveling direction of light. 4. The condensing optical system comprises a condensing lens array having a positive power, and has a focal length such that the position of a polarization beam splitter of the polarization conversion optical system and the position of a light emitting point are substantially conjugate. The projection display device according to claim 1, wherein the setting is set. 5. The projection display device according to claim 1, wherein a light emission area of the light source array including the plurality of solid-state light sources is larger than a light reception area of the two-dimensional spatial light modulator. 6. The projection display apparatus according to claim 1, wherein the number of light sources corresponding to red light, green light, and blue light of the light source array including the plurality of solid-state light sources is not the same. 7. An image of light in the vicinity of the condensing optical system,
2. The projection display device according to claim 1, further comprising an illumination lens for forming an image on the three-dimensional spatial light modulator in a multiplex manner. 8. An illumination system that generates at least red light, green light, and blue light, a two-dimensional light modulator that modulates each of the red light, green light, and blue light according to image information, and the two-dimensional light. In a projection type display device for projecting modulated light from a modulator, the illumination system may include a plurality of solid-state light sources arranged in a matrix and a plurality of light-emitting points of the solid-state light sources formed of a plurality of lenses. A light condensing optical system arranged so as to project onto one lens of the optical lens array, and a polarization conversion optical system for polarizing light from the light condensing optical system to the two-dimensional light modulator. Characteristic projection display device. 9. An illumination system that generates at least red light, green light, and blue light, a two-dimensional light modulator that modulates each of the red light, green light, and blue light according to image information, and the two-dimensional light. In a projection display device for projecting modulated light from a modulator, the illumination system includes a plurality of solid-state light sources arranged in a line, and a line-shaped light-emitting point of the solid-state light source, which is one lens of a cylindrical lens array. And a polarization conversion optical system that polarizes the light from the light collection optical system to the two-dimensional light modulator.