JP3473075B2 - Lighting device and projection display device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination device for uniformly illuminating a rectangular object and a projection display device for enlarging and displaying an image of a liquid crystal panel on a screen.

[0002]

2. Description of the Related Art As a method of uniformly illuminating a rectangular object, there is a method of using an integrator composed of two lens plates. The integrator is a lens plate having a plurality of lenses closely arranged, that is, a so-called fly-eye lens arranged in parallel, and divides a non-uniform light beam irradiated on one lens plate into a plurality of light beams. That is, the light flux is superimposed and imaged on the illumination target.

FIG. 1 shows a basic configuration when an illumination system using an integrator is applied to a liquid crystal projector which is one of projection type display devices. The light emitted from the light source lamp 101 is reflected by the reflector 102 and emitted as a substantially parallel light beam. The first lens plate 103 has a configuration in which a plurality of rectangular lenses are arranged in a matrix, and each rectangular lens forms an image of the light emitting portion of the light source lamp 101 at the center of the corresponding rectangular lens in the second lens plate 104. And
The image of each rectangular lens of the first lens plate 103 is superimposed and formed on the display unit of the liquid crystal panel 109 by the functions of the second lens plate 104 and the auxiliary lens 106. Here, the first lens plate 103 and the second lens plate 104 having the same structure are used, and the focal length of each rectangular lens is equal to the distance between them. The focal length of the auxiliary lens 106 is equal to the distance between the auxiliary lens 106 and the liquid crystal panel 109. The collimating lens 108 collimates the divergent light flux from the integrator and makes a vertical light flux incident on the entire surface of the liquid crystal panel 109, and is necessary to make the contrast ratio of the image uniform on the entire display surface. The condenser lens 110 condenses the light flux transmitted through the liquid crystal panel 109 on the entrance pupil of the projection lens 112, and the image of the second lens plate 104 of the integrator is formed on the entrance pupil. In a three-panel liquid crystal projector that projects and displays a color image by using three liquid crystal panels, in order to separate the illumination light flux into three primary color lights,
A color separation system 10 is provided between the integrator and the liquid crystal panel 109.
7 is arranged, and a color combination system 111 is arranged between the liquid crystal panel 109 and the projection lens 112 in order to combine the light beams emitted from the three liquid crystal panels into one. A specific method of using an integrator in a liquid crystal projector is described in detail in Japanese Patent Laid-Open No. 3-111806.

A high-definition television is a promising medium in the future, and the display of this high-definition television has an aspect ratio of 9:16, which is considerably longer than the aspect ratio of NTSC television 3: 4. Has become. In a liquid crystal projector for high definition television, the aspect ratio of the rectangular lenses included in the two lens plates of the integrator is 9:16, which is the same as the aspect ratio of the display section of the liquid crystal panel. An example of the configuration of the integrator in this case is shown in FIG.
Shown in (A) and (B). The first lens plate 103 has a configuration in which fifteen rectangular lenses 202 having an aspect ratio of 9:16 are arranged in a matrix, and the entire lens plate has a size that is substantially inscribed in the reflector 102 in FIG. The second lens plate 104 has exactly the same configuration as the first lens plate 103, and a light source image 105 that is an image of the light emitting portion of the light source lamp 101 is formed at the center of each rectangular lens.

[0005]

However, in the integrator using the rectangular lens having the aspect ratio of 9:16, the blank area 204 without the light source image exists between the light source images 105 formed on the second lens plate. However, the second lens plate is larger than necessary. When an illuminating device having a large second lens plate is used in a liquid crystal projector, there are problems such as occurrence of color unevenness due to the angle dependence of a color separation system or a color combination system, and the need for making the projection lens larger than necessary. It was There is also a problem that the size of the color separation system becomes large.

Further, in order to improve the effective aperture ratio of the liquid crystal panel by arranging a microlens array on the light beam incident side of the liquid crystal panel, the arrangement of the light source images 105 on the second lens plate 104 and the liquid crystal panel are arranged. There is a problem in that the microlens array cannot be used because the pixel arrays do not match.

Therefore, the present invention solves such a problem, and an object thereof is to provide an illuminating device using an integrator in which the size of the second lens plate is made as small as possible. It is to be. Further, by using this illuminating device for a projection display device, it is possible to realize a projection display device which is easy to design an optical path and a projection lens, has a small size, and is capable of displaying bright and high-quality images. . Another object of the present invention is to provide a projection display device that is brighter and has higher light utilization efficiency by using a microlens array that further improves the effective aperture ratio of the liquid crystal panel.

[0008]

An illumination device according to the present invention includes a light source lamp, a reflector which reflects a light beam emitted from the light source lamp in one direction, and a light beam which is reflected from the reflector in a direction perpendicular to a central axis of the light beam. A first lens plate arranged on the reflector side of the two lens plates, in which a plurality of rectangular lenses are closely arranged. In the illuminating device which has a configuration in which a plurality of lenses are closely arranged by a second lens plate arranged at a certain distance, and which uniformly illuminates a rectangular illumination target perpendicular to the central axis of the light flux, the first lens plate And the array of the lenses included in the second lens plate are the same, and the lens optical axis of the rectangular lens is formed by the rectangular lens from the center of the rectangular lens. Is shifted in the direction of the center of the column that,
By making the dimension of the second lens plate in the direction smaller than the dimension of the first lens plate in the direction,
The aspect ratio of the entire lens plate is different from the aspect ratio of the second lens plate.

The aspect ratio of the entire first lens plate is approximately 1:
2, and the aspect ratio of the entire second lens plate is approximately 1: 1.

A polarization beam splitter and a polarization conversion system including a half-wave plate are arranged between the reflector and the first lens plate.

The present invention is characterized in that two light source devices each including the light source lamp and the reflector are provided, and the respective emitted light beams are applied to the first lens plate in parallel.

The aspect ratio of the rectangular lens included in the first lens plate is 9:16, and the lens included in the second lens plate is substantially square.

The aspect ratio of the rectangular lens included in the first lens plate is 9:16, and the lens included in the second lens plate is approximately a hexagon.

The projection type display device of the present invention includes the above-mentioned illumination device, a liquid crystal panel that modulates a light beam from the illumination device to form an optical image, and an optical image formed on the liquid crystal panel on a screen. With a projection optical system
A lens is arranged in the vicinity of the liquid crystal panel to form an image of a light flux emission portion of the illumination device in an entrance pupil of the projection optical system.

[0015]

[0016]

[0017]

[0018]

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

FIG. 3 shows a basic configuration example of the illumination device of the present invention.
Shown in. A configuration example is shown in FIG. The light source lamp 101 is a light source close to a point such as a halogen lamp, a metal halide lamp, and a xenon lamp, and the light flux emitted from the light emitting portion is reflected by the reflecting mirror 102 and becomes a light flux that is nearly parallel. The first lens plate 301 of the integrator has a configuration in which rectangular lenses that are similar to the shape of the illumination target are arranged in a matrix, and is shown here as illuminating the liquid crystal panel 109 having an aspect ratio of 16: 9. Therefore, the aspect ratio of the rectangular lens is also 9:16. Further, the shape of the entire first lens plate 301 is a circular reflector 1.
The shape is close to a square inscribed with 02. On the other hand, the second lens plate 302 uses a square lens as the first lens plate 3.
The rectangular lenses in No. 01 are arranged in the same arrangement, and the vertical size of the entire second lens plate 302 is the first.
Same as the lens plate 301, the horizontal size is about one half of the first lens. The light source image 105 is formed at the center of each square lens on the second lens plate.
There is no blank area as seen in (B). In this way, in order to closely arrange the light source images 105 on the second lens plate 302, the lens optical axis 303 of the rectangular lens on the first lens plate 301 is slightly shifted from the rectangular center 304. That is, of the three columns, the lens optical axis 303 is shifted in the direction of the central column, and the lens optical axis 303 is also shifted in the direction of the central column in the right column. Therefore, the second lens plate 3
The light source image 105 at 02 is compressed only in the lateral direction.

As described above, reducing the size of the second lens plate is advantageous in the optical system of the projection display device. As shown in FIG. 3, the white light flux emitted from the second lens plate 302 then enters a color separation system 107 for separating the light flux into three primary color lights. The color separation system 107 is composed of a dichroic mirror, and its color separation characteristic has angle dependence. Therefore, the smaller the apparent light source, the smaller the variation in the angle of the incident light beam, and the better the color separation characteristic. There is a tendency. In addition, the color separation system 107
Can be made smaller as the size of the second lens plate 302 becomes smaller. Further, in the projection display device, the image of the second lens plate 302 is formed in the entrance pupil of the projection lens 112 in FIG. 1, so that if the size of the second lens plate 302 is small, the size of the projection lens is also small. be able to. Alternatively, since the luminous flux incident on the projection lens does not pass through the peripheral portion of the effective diameter of the projection lens so much, the resolution of the projected image is improved.

FIG. 4 is a diagram showing a configuration example of the illuminating device according to the present invention. In the lighting device used for the projection display device,
In order to reduce the overall thickness of the device, a reflector whose top and bottom are cut may be used, and in such a case, a configuration to which the present invention is applied is shown. Since the reflector 102 is cut at the top and bottom, the cross section of the emitted light beam has a shape close to an ellipse. Therefore, the first lens plate 401 is
As shown in the figure, it becomes a horizontally long array. Similar to the method described above, if the method of shifting the lens optical axis of the rectangular lens included in the first lens plate 401 from the rectangular center is used, the light source image 1 formed in the second lens plate 402 is formed.
05 can be closely arranged, and similarly to the previous example, the rectangular lens included in the second lens plate 402 can have a shape close to a square. Also in this example, the lateral width e of the second lens plate 402 is considerably smaller than the lateral width d of the first lens plate 401, and the overall shape of the second lens plate 402 is close to a square. Since the entrance pupil of the projection lens used in the projection display device is generally circular, the second lens plate 40
When the shape of 2 is not horizontally long like the first lens plate 401 but is close to a circle, the design of the projection lens is facilitated and the utilization efficiency of the light flux is improved.

Next, FIG. 5 shows a structural example of the illuminating device of the present invention when two light source lamps are used. The light source device including the light source lamp 101 and the reflector 102 has two
The first lens plates 501 of the integrator are arranged in the light emitting portion of the light flux so as to substantially cover the cross section of the light flux. Therefore, the first lens plate 501 has an aspect ratio close to 1: 2. On the other hand, the second lens plate 502 is compressed only in the lateral direction, and the lateral width g of the second lens plate 502 is about one half of the lateral width f of the first lens plate 501.
Since the aspect ratio of the rectangular lens 501 included in the first lens plate 501 is also 9:16, the second lens plate 502.
Has a shape close to a square, and since each rectangular lens has a square shape, the light source image is the second lens plate 50.
2 are evenly arranged over the entire area. In the projection display device, the image of the second lens plate 502, which is the secondary light source, is formed on the entrance pupil of the projection lens, and since the entrance pupil is circular, the compatibility with the square secondary light source is good. The use of two light source devices in a projection display device is an advantageous method for energy saving because it is possible to turn off either one of the lamps when brightness is not required so much. In addition, the PDL in which the liquid crystal panel 109 controls the incident light flux by the scattering degree.
When the C element is used, there is an advantage that either one of the lamps can be turned off to double the contrast ratio. Note that, as shown in FIG. 5, the first lens plate 501 can reduce the decentering amount of the decentered rectangular lens included in the first lens plate 501 by disposing the two lens plates slightly inward. .

FIGS. 6A and 6B are diagrams showing an example of constructing a highly efficient polarized light source device to which the present invention is applied. The light flux emitted from the light source lamp 101 is reflected by the reflector 102 and is incident on the aspherical lens 601 to be a uniform and parallel light flux. The reflector 102 distributes the light flux with poor parallelism reflected at the central portion to the peripheral portion of the aspherical lens 601,
A light beam with good parallelism reflected by the peripheral portion of the reflector is made to enter the aspherical lens 601 slightly inward. Therefore, a light beam having a substantially uniform angular distribution is incident on the aspherical lens 601, and the aspherical lens 601 converts the principal ray of each light beam into a direction substantially parallel to the optical axis. It is necessary to form a parallel and uniform light flux in this way in order to minimize the influence of the angle dependence of the polarization beam splitter 602 that is incident next. The polarization beam splitter 602 transmits incident p-polarized light and reflects s-polarized light at an angle of 90 degrees. The polarization beam splitter 602 has no problem with the angle dependence of the incident light beam within an angle range of ± 5 degrees, but at a larger angle, the p-polarized light is not transmitted and is reflected, so that the efficiency is high. In order to increase the value, it is necessary to make a uniform and parallel light beam incident. Now, the p-polarized light is transmitted through the polarization beam splitter 602, and the reflected s-polarized light is further reflected by the reflecting mirror 603, and travels in substantially the same direction as the p-polarized light. The light flux reflected by the reflecting mirror 603 converts its polarization direction into p-polarized light, and therefore has a wavelength of λ / 2.
The plate 604 is passed. Therefore, the two light fluxes that are emitted with the same polarization direction enter the first lens plate 605 next. The shape of the first lens plate 605 is horizontally long as in the case of FIG. 5, and the aspect ratio of the rectangular lenses included in the first lens plate 605 is 9:16. As for the second lens plate 606, the overall shape is substantially square as in the case of FIG.
In a liquid crystal projector that uses a liquid crystal panel as a modulation element, only one of the light beams incident on the liquid crystal panel 109 is used. Therefore, an illuminating device that converts all the light beams emitted from the light source lamp 102 into the same polarized light as described above. There is an effect that the efficiency of light utilization is approximately doubled. Further, this lighting device may be configured as shown in FIG. In this case, two polarization beam splitters 602 and reflecting mirrors 603 in FIG. 6A are arranged symmetrically with respect to the optical axis. However, here, in FIG.
The reflecting mirror 603 in FIG.
Replaced by. Two polarization beam splitters 602
The p-polarized light is transmitted as it is, and the s-polarized light is split into two and reflected by the prism 607. This prism 607 may be a flat plate reflecting mirror, but if it is configured with a prism, the reflecting surface can be totally reflected, and if all five surfaces of the triangular prism are optically flat surfaces, the prism 607 will be The leaking light flux can be returned to the inside by total internal reflection. With this configuration, the thickness of the polarization beam splitter can be halved, and the optical path can be shortened to half, which is very advantageous in terms of efficiency.

FIGS. 7 (A) and 7 (B) are diagrams showing a configuration example of an integrator used in the lighting apparatus of the present invention. Figure 7
As shown in (A), in the first lens plate 701, the rectangular lenses arranged in the row direction are displaced from each other by a half of the width of the rectangular lenses with respect to the upper and lower ones, not in a matrix arrangement in a grid pattern. Will be placed. Each rectangular lens has an aspect ratio of 9:16, and the aspect ratio of the entire lens plate is 1: 2. In the second lens plate 702, as shown in FIG. 7B, each rectangular lens is close to a square, and the entire lens plate is close to a circle. In addition, the second lens plate 7
Each lens included in 02 may be a hexagon. Thus, when the rectangular lenses in the column direction are arranged in a zigzag manner, the light source images 105 formed on the second lens plate 702 also have the same arrangement, and as described later, a microlens array is used for the liquid crystal panel of the liquid crystal projector. It is an array suitable for each case.

FIGS. 8 (A) and 8 (B) show a structure in which a series of lenses in the column direction are moved up and down alternately. Also in this case, the entire first lens plate 801 has an aspect ratio of 1 :.
2, the included rectangular lens has an aspect ratio of 9:16.
As shown in FIG. 8B, two types of second lens plates 802 and 803 can be considered, in which the constituent lenses have a substantially square shape and a hexagonal shape. In the case of the hexagonal shape, it can be a regular hexagon, and at this time, the lateral width of the second lens plate 803 is equal to that of the second lens plate composed of square lenses.
It is smaller than that of the lens plate 802. Further, since the hexagon is closer to a circle than a square, the light source image 105 is likely to fit.

The structure of the integrator shown in FIGS. 9A and 9B is designed to make the second lens plate 902 close to a circle. The number of rectangular lenses in the column direction on the first lens plate 901 is increased toward the central portion. In the second lens plate 902, the central lens has a pentagonal shape and the peripheral part has a hexagonal shape. Also, these lenses may be square. In this configuration, the second
Since the lens plate 902 can be formed into a substantially circular shape, when the integrator of this configuration is used in the projection display device, the matching property with the entrance pupil of the projection lens is excellent.

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

As described above, according to the present invention, in the illumination device using the integrator, the aspect ratio of the first lens plate and the aspect ratio of the second lens plate are different from each other,
By closely arranging the light source images formed on the second lens plate, it is possible to make the entire secondary light source a minimum size. Further, when the cross section of the light beam from the light source device is horizontally long, the light beam can be compressed only in the horizontal direction, and the shape of the entire secondary light source can be made to have a shape with an aspect ratio close to 1: 1.

Further, in the projection display device of the present invention, the size of the color separation system can be reduced by using the above-mentioned illumination device, and the size of the projection lens can be further reduced. Therefore, a small projection display device can be realized.

[0034]

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a conventional lighting device and a projection display device.

FIG. 2A is a first diagram used in a conventional lighting device.
The figure which shows the structure of a lens plate. FIG. 6B is a diagram showing a configuration of a second lens plate used in a conventional lighting device.

FIG. 3 is a diagram showing a basic configuration of a lighting device of the present invention.

FIG. 4 is a diagram showing a configuration example of a lighting device of the present invention.

FIG. 5 is a diagram showing a configuration example of a lighting device of the present invention.

FIG. 6A is a diagram showing a configuration example of a lighting device of the present invention. FIG. 6B is a diagram showing a configuration example of a lighting device of the present invention.

FIG. 7A is a diagram showing a configuration of a first lens plate used in the illumination device of the present invention. FIG. 6B is a diagram showing the configuration of the second lens plate used in the lighting device of the present invention.

FIG. 8A is a diagram showing a configuration of a first lens plate used in the illumination device of the present invention. FIG. 6B is a diagram showing the configuration of the second lens plate used in the lighting device of the present invention.

FIG. 9A is a diagram showing a configuration of a first lens plate used in the illumination device of the present invention. FIG. 6B is a diagram showing the configuration of the second lens plate used in the lighting device of the present invention.

[Explanation of symbols]

101 light source lamp 102 reflector 103 First lens plate 104 second lens plate 105 light source image 108 Parallelizing lens 109 LCD panel 112 Projection lens 602 Polarizing beam splitter 604 λ / 2 plate

Claims (7)

(57) [Claims] 1. A light source lamp, a reflector for reflecting a light beam emitted from the light source lamp in one direction, and two lens plates arranged perpendicularly to a central axis of a light beam reflected from the reflector, Of the two lens plates, the first lens plate arranged on the reflector side has a configuration in which a plurality of rectangular lenses are closely arranged, and the second lens plate arranged at a certain distance from the first lens plate. Is a configuration in which a plurality of lenses are closely arranged, in an illumination device for uniformly illuminating a rectangular illumination target perpendicular to the central axis of the light flux,
The arrangement of the rectangular lenses included in the first lens plate and the arrangement of the lenses included in the second lens plate are the same, and the lens optical axis of the rectangular lens is formed by the rectangular lens from the center of the rectangular lens. By shifting the dimension of the second lens plate in the direction to be smaller than the dimension of the first lens plate in the direction, the aspect ratio of the entire first lens plate and the 2. An illuminating device characterized in that the overall aspect ratio of the two lens plates is different. 2. The aspect ratio of the entire first lens plate is approximately 1: 2, and the aspect ratio of the entire second lens plate is approximately 1: 2.
The lighting device according to claim 1, wherein the lighting device is 1. 3. A polarization beam splitter and a polarization conversion system including a ½ wavelength plate are arranged between the reflector and the first lens plate. Illumination device described. 4. The illuminating device according to claim 2, wherein the light source device including the light source lamp and the reflector is provided in two lines, and the respective luminous fluxes emitted from the light source device are irradiated in parallel to the first lens plate. . 5. The aspect ratio of the rectangular lens included in the first lens plate is 9:16, and the lens included in the second lens plate is substantially square. The lighting device according to any one of 1. 6. The aspect ratio of the rectangular lenses included in the first lens plate is 9:16, and the lenses included in the second lens plate are substantially hexagonal. The illumination device according to any one of claims 1 to 4. 7. The illuminating device according to claim 1, a liquid crystal panel that modulates a light beam from the illuminating device to form an optical image, and an optical image formed on the liquid crystal panel is enlarged and displayed on a screen. And a projection optical system for forming a lens, the lens is disposed in the vicinity of the liquid crystal panel, and an image of a light flux emitting portion of the illumination device is formed in an entrance pupil of the projection optical system. .