JP2000089166A - Polarization device and projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarization device and a projection type display device by which high luminance and uniform illumination are realized. SOLUTION: The devices are provided with a first lens plate 2, in which plural lenses are arranged in a planar manner and approximately parallel fluxes emitted from a light source are divided into plural light fluxes by an aperture constituted of the plural lenses, a second lens plate 3, in which plural lenses are arranged in a planar manner and the lenses are respectively arranged at the focal positions of the plural lenses of the plate 2, a polarization beam splitter array 4, which is made by pasting plural polarization beam splitters arranged on the light emitting surface side of the plate 3 together in a planar manner, a 1/2 wavelength phase plate 5, which is arranged on the light emitting surface of the polarization light beam splitters forming the array 4 and converts one of the P polarized light beams or the S polarized light beams emitted from the light emitting surface to other polarization light beams, and a light reflecting layer 8 which is located between the light emitting surface of the plate 3 and the array 4 and arranged at the position corresponding to the boundary of the lenses constituting the plate 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing device and a projection type display device for converting a light source light into a single polarized light and illuminating a liquid crystal light valve.

[0002]

2. Description of the Related Art A light valve illuminating device shown in FIG. 5 is known as a device for converting light from a light source into single linearly polarized light and illuminating the light valve with the polarized light. The configuration of this device will be described. Light source light of a substantially parallel light flux emitted from a light source 101 composed of a lamp and a concave mirror having a parabolic mirror shape is incident on a first lens plate 102 in which a plurality of lenses 102a are arranged in a plane. Divided injection is performed by an opening determined by the outer shape. The outer shape of each lens 102a is similar to that of the light valve 107, which is the object to be illuminated, and is proportionally reduced. The position of the focal point of each lens 102a of the first lens plate 102 is
The second lens plate 103 in which the second lens 103a is arranged in a plane corresponding to the lens 102a of the lens plate is arranged.

Further, a polarizing beam splitter array in which a plurality of polarizing beam splitters 104 are arranged in a plane is arranged on the exit surface side of the second lens plate 103. The width of the cross-sectional shape of the polarizing beam splitter 104 constituting the polarizing beam splitter array is equal to the width of the lens 10 of the second lens plate.
That is, the polarizing beam splitter 104 constituting the array is arranged at a position corresponding to a boundary position and a substantially central position of the lens 103a. Further, a half-wave phase plate 105 is arranged on the exit surface of the polarization beam splitter arranged at the substantially central position.

Further, the polarization beam splitters 104 of the polarization beam splitter array are all arranged in parallel. Because of the arrangement of the first lens plate 102 and the second lens plate 103 as described above, the parallel light source luminous flux incident on each lens 102a of the first lens plate is emitted and the second light beam corresponding to each lens is emitted.
The light is condensed and incident on the lens 103a of the lens plate, and forms a bright spot on the second lens plate. The light emitted from the luminescent spot of the second lens plate is incident on a polarization beam splitter arranged substantially at the center of the emission section of the second lens 103a, is reflected by the polarization separation section and is incident on an adjacent polarization beam splitter. S-polarized light reflected and emitted by the polarization splitting unit of the polarization beam splitter and P-polarized light transmitted through the polarization splitting unit. The polarized light is S-polarized light by the 波長 wavelength phase plate disposed on the emission surface. And is separated into light to be emitted.

As described above, in the conventional example, the emitted S-polarized light is emitted from the condenser lens 106 disposed near the exit surface.
By illuminating the light valve 107 in a superimposed manner by the number of lenses of the first lens plate through the above, uniform illumination with single linearly polarized light is possible. The light valve 107 is a transmissive light valve in which a liquid crystal panel is sandwiched between two polarizing plates. The polarizing plate disposed in front of the incident surface transmits S-polarized light and absorbs P-polarized light. It has the following characteristics.

[0006]

The above is a description of the principle of a conventional polarizing device that converts a light source light into a single polarized light (S-polarized light) and superimposes the light, and is formed on a lens 103a of a second lens plate 103. The bright spot (light source image) to be formed has a point shape. However, actually, the bright spot (light source image) formed on the lens 103a of the second lens plate 103 is not a point shape but has a finite size, and particularly the lens 103a on or near the optical axis. The image formed thereon is large and may be larger than the lens 103a. This size becomes smaller as it is closer to the optical axis and closer to the periphery. This is due to the fact that the light emitting portion of the lamp of the light source 101 has a finite size instead of a point shape, but has the following problem due to the size of the luminescent spot. Turned out to be.

FIG. 6 is a diagram for explaining a problem in a conventional polarizing device. The light emitted from the single bright spot A near the optical axis is polarized and separated by the polarization beam splitter 104a.
The transmitted P-polarized light is converted into S-polarized light by a half-wave plate provided on the exit surface of the polarizing beam splitter. On the other hand, the S-polarized light separated and reflected by the polarization beam enters the adjacent polarization beam splitter, is reflected by the polarization separation surface, and is emitted as illumination light of the light valve. However, the light source image (bright point) formed on the lens 103a in the vicinity of the optical axis may be over the entire lens 103a according to the above description, or
It is larger than that, and also has a bright portion near the vicinity of the lens 103a and the adjacent lens 103a. For example, considering light emitted from a single bright point A ′ near the boundary between the bright portion and the adjacent lens in the drawing, the light is emitted from the portion, enters the polarization beam splitter, passes through the polarization separation unit, and exits as it is. P-polarized light and S-polarized light reflected by the polarization splitter and incident on the adjacent polarization beam splitter are reflected by the polarization splitter of the polarization beam splitter,
The light is converted into P-polarized light by the half-wavelength phase plate 105 formed at the emission part of the polarization beam splitter and emitted. As described above, the light emitted from the luminescent spot A ′ is emitted to the light valve 107 in FIG. 5 as unnecessary P-polarized light which is supposed to be originally illuminated with S-polarized light, and illuminated.

For this reason, there is a problem that the S-polarized light incident on the liquid crystal panel of the light valve 107 decreases and the brightness of the projected image decreases. Furthermore, since the polarizing plate disposed on the light-incident surface of the light valve 107 is configured to absorb P-polarized light, when the output of the light source is increased, the amount of P-polarized light inevitably increases. The polarizing plate absorbs the P-polarized light, and the heat generated thereby causes a problem that the performance of the polarizing plate is deteriorated.

An object of the present invention is to solve the above problems and to provide a polarizing device and a projection type display device which realize uniform illumination with high brightness.

[0010]

An embodiment of the polarizing device of the present invention is a lens plate in which a plurality of lenses are arranged in a plane, and an approximately parallel light beam emitted from a light source is formed by an aperture formed by the plurality of lenses. A first lens plate that divides the light into a plurality of light beams, and another lens plate that has a plurality of lenses in a plane, wherein the lenses are respectively disposed at focal positions of the plurality of lenses of the first lens plate. No. 2 lens plate, a polarizing beam splitter array in which a plurality of polarizing beam splitters disposed on the second lens plate emitting surface side are planarly bonded, and an emitting surface of the polarizing beam splitter constituting the polarizing beam splitter array A half-wave phase plate for converting one of P-polarized light or S-polarized light emitted from the emission surface into the other polarization, and the emission surface of the second lens plate and Between the optical beam splitter array is one in which a structure having a light reflection layer disposed at a position corresponding to the boundary of the lenses constituting the second lens plate.

An embodiment of the projection type display device according to the present invention is a light source for emitting a substantially parallel light beam, and a lens plate on which a plurality of lenses are arranged in a plane. A first lens plate that divides the light into a plurality of light beams by an aperture formed by the first lens plate, and another lens plate having a plurality of lenses in a plane, wherein the first lens plate is located at a focal position of the plurality of lenses. , A polarizing beam splitter array in which a plurality of polarizing beam splitters disposed on the second lens plate exit surface side are bonded in a plane, and an exit surface of the second lens plate. A polarizing device including, between the polarizing beam splitter array, a light reflecting layer disposed at a position corresponding to a boundary of a lens configuring the second lens plate;
A color separation optical system that color-separates the light emitted from the polarizing device into R, G, and B color lights; and R, G, and B colors that image-modulate the color lights separated by the color separation optical system. A light valve, a color combining optical system that combines the color lights modulated by the light valve, and a projection optical system that projects the light combined by the color combining system as a projection image onto a screen. Things.

[0012]

(First Embodiment) FIG. 1 is a configuration diagram showing a first embodiment of a light valve illuminating device using a polarizing device of the present invention. FIG. 2 is a configuration diagram showing the polarizing device of the present invention. FIG. 1 will be described. A substantially parallel light source luminous flux emitted from a light source 1 composed of a lamp and a concave mirror having a parabolic shape is incident on a first lens plate 2 on which a plurality of lenses 2a are arranged in a plane,
At an opening determined by the outer shape of the lens 2a, the light beams are divided into the number of light beams equal to the number of the lenses 2a, and the light beams are emitted from the lenses. The outer shapes of the lenses 2a are all the same, and the outer shape of a light valve, which will be described later, is a proportionally reduced shape.

At the focal position of each lens 2a of the first lens plate 2, a second lens plate 3 in which a second lens 3a is arranged in a plane at a corresponding position is arranged. Second lens plate 3
The reflection layer 8 is disposed close to (in contact with) the exit surface of the second lens plate at a position corresponding to the boundary between the lens 3a and the adjacent lens of the second lens plate in the longitudinal direction of the polarizing beam splitter (in the direction perpendicular to the paper surface). The reflection layer 8 is not disposed at the exit portion corresponding to the central portion of the lens plate 3a.

In the polarization beam splitter array, a reflection layer 8 is sandwiched between the array and the second lens plate 3, and the polarization beam splitters 4p of the plurality of polarization beam splitters 4 constituting the array are all arranged in parallel. It has a bonded configuration. The length (width) of one side of the shape shown by the cross-sectional shape of the polarizing beam splitter 4 is the second lens 3 a of the second lens plate 3.
Is approximately half the width of the lens plate 3 and the lens plate 3 is arranged so as to coincide with the center of the lens 3a or the boundary position with the adjacent lens.

Further, of the polarization beam splitters 4 constituting the polarization beam splitter array, a half-wavelength phase plate is provided only on the exit surface of the polarization beam splitter 4 disposed at the center of the lens 3a of the second lens plate 3. 5 is arranged. A condenser lens 6 is arranged near the exit surface of the polarization beam splitter array. In addition,
In the present embodiment, the light valve 7 as an illuminated object is a transmission type light valve, and the configuration is such that a switching element such as a TFT in which a plurality of pixels are arranged for each pixel can be switched based on an image signal. In addition, it is possible to change the incident polarized light into the polarized light having a vibration direction different from the incident polarized light, from the light emitted from the liquid crystal layer portion corresponding to the pixel related to the switching.

That is, the transmission type light valve 7 has a configuration in which a liquid crystal panel having the above-mentioned function is sandwiched between polarizing plates constituting orthogonal Nicols. Is configured to be absorbed by the polarizing plate on the emission surface side and not emitted. Further, details of the polarizing device of the present invention will be described with reference to FIGS. FIG. 3 shows another configuration of the polarizing device including the first lens plate, the second lens plate 3, the reflecting plate 8, the polarizing beam splitter array, and the half-wave phase plate 5, excluding the first lens plate. It is a perspective view of a member. Note that this drawing is a configuration diagram viewed obliquely from the exit surface side.

As described above, each light beam incident on the lens 2a of the first lens plate and divided by each lens 2a forms an image on the lens 3a of the second lens plate disposed at a position corresponding to the first lens 2a. However, as described in the related art, it does not always form an ideal point-shaped bright spot image. In particular, the second lens 3a corresponding to the optical axis position (near the center) has a large area. (Beyond the boundary with the adjacent lens) to form the image. The size of this image is
As the distance from the center increases, the size of the bright spot becomes smaller. Hereinafter, this spread image is referred to as a bright portion.

Light emitted from a single bright spot near the optical axis of the bright portion formed on the lens 3a near the optical axis of the second lens plate exits the second lens and travels to the polarizing beam splitter array. The light emitted from a single bright spot near the boundary between the bright portion and the adjacent lens enters the reflective layer 8 and undergoes a reflection action, and travels backward in the direction of the light source.
Thus, the light from the lens plate 3 does not directly enter the polarizing beam splitter 4 disposed at the boundary position of the lens 3a of the second lens plate 3. Therefore, the light passes through the polarization beam splitter 4 or reflects from the polarization splitting unit and enters the adjacent polarization beam splitter from the side surface. As a result, there is no emission of P-polarized light.

Further, the light traveling backward and traveling in the direction of the light source passes through the first lens plate 2 and travels in the direction of the light source, is reflected by the concave mirror, is incident on the lens plate 2 again, and is used as light source light. Is used again as illumination light, but the light of the light which enters the reflection plate 8 via the second lens plate is similarly reflected again, so that the light is transmitted and proceeds. Emitted as polarized light also disappears.

The light incident on the polarization beam splitter 4 disposed at a position corresponding to the center of the lens 3a is polarized and separated by the polarization separation section 4p of the polarization beam splitter 4, and the P-polarized light that travels through the section. The polarized light, which is converted into S-polarized light by the half-wavelength phase plate disposed on the exit surface, is reflected and incident on the adjacent polarizing beam splitter, reflected by the polarization splitting unit, and emitted as it is. S
It is polarized and separated into polarized light. As described above, the light emitted from the single bright point is reflected by the reflection layer 8, becomes light that goes backward to the light source side, and returns to the second lens again. Of the returned light, the light that has progressed to the vicinity of the center of the lens 3a of the lens plate 3 enters a polarization beam splitter disposed at the center of the lens 3a. The return light passes through the polarization beam splitter and is converted by the half-wavelength phase plate disposed on the exit surface to become S-polarized light. On the other hand, the S-polarized light reflected by the polarization beam splitter of the polarization beam splitter enters the adjacent polarization beam splitter from the side, and becomes S-polarized light reflected by the polarization beam splitter of the polarization beam splitter. Both can illuminate the light valve with their polarization directions aligned.

By arranging the reflective layer 8 at the above-mentioned position, P-polarized light is not emitted, and a part of the light returning to the light source in the reverse direction is illuminated as S-polarized light. Therefore, high-brightness illumination with single linearly polarized light of the light valve 7 can be achieved. Further, since the P-polarized light as in the conventional example is not mixed with the illumination light, the absorbed polarized light is not made incident on the polarizing plate disposed on the incident surface of the light valve. The performance of the polarizing plate does not deteriorate due to heat.

In the above embodiment of the present invention, the polarized light incident on the light valve is S-polarized light, but it may be P-polarized light having a vibration direction in another direction. For this purpose, the half-wave phase plate disposed on the exit surface of the polarization beam splitter is different from the case of the present embodiment and is the exit surface of the polarization beam splitter and corresponds to the portion of the lens plate 3 adjacent to the lens 3a. The polarization beam splitter may be disposed on the exit surface of the polarization beam splitter disposed at the position where the light beam is split.

As shown in FIG. 3, the reflecting layer 8 is physically formed on the exit surface of the lens plate 3 such that aluminum is used as a reflecting layer, for example, so as to be parallel to a strip at positions corresponding to adjacent portions of the lens 3a. It may be formed by an evaporation method.
As still another means, a structure in which aluminum is formed in the same band shape on a transparent glass plate as the reflection layer 8 may be arranged between the lens plate 3 and the polarizing beam splitter array. (Second Embodiment of the Invention) In the second embodiment of the present invention, a light absorption layer is disposed instead of the reflection layer 8 used in the previous embodiment. Therefore, the configuration diagram is the same as that of FIG. 1, and the configuration is such that the reflection layer 8 is replaced with a light absorption layer. In the case of this light absorbing layer, the light incident on the absorbing layer is absorbed by the layer, is not reflected, and does not pass through to enter the polarizing beam splitter.

As a result, as compared with the previous embodiment, the illumination of the light valve is achieved with single linearly polarized light (S-polarized light), the P-polarized light is not mixed with the light, and the light is arranged on the light valve incident side. Although the performance is not degraded by the light absorbed by the polarizing plate, the reflected light and the light that contributes to the illumination again in the previous embodiment are also absorbed. , The illumination luminance of the correspondingly decreases.

In the case of this embodiment, the structure of the light absorbing layer is as follows.
Similar to the reflector in the previous embodiment, a light absorbing layer coated with black paint, black, or the like may be formed on the exit surface side corresponding to the lens boundary portion of the lens plate 3, and further, a glass plate member Similarly, the structure in which the absorption layer is formed may be arranged between the lens plate 3 and the polarizing beam splitter array so that the absorption layer is arranged at a predetermined position. (Third Embodiment of the Invention) This embodiment is an embodiment of a lighting apparatus using a reflection type light valve as a light valve. FIG. 4 is a configuration layout diagram of the entire projection display device using the polarizing device and the illumination device of the present invention. For R light, G
Reflection type light valves are arranged for light and B light, respectively. For comparison with the illuminating device of the first embodiment, only the progression of G light will be described.

The difference from the first embodiment resides in that the light valve is a reflection type light valve 16G and that a polarizing beam splitter 12G is arranged immediately before the light valve. The components of the polarizing device are the same as in the first embodiment, and a description thereof will be omitted.

The illumination light emitted from the condenser lens 6 is the same as that in the first embodiment, and is S-polarized light. Of the light, the G light is a B light reflecting dichroic mirror 9B and an R, G light reflecting dichroic. The light is color-separated by a cross dichroic mirror 9 composed of a mirror 9RG, further reflected by a bending mirror 13 and a G light reflecting dichroic mirror 14, and is incident on a polarization beam splitter 12G. The G color light incident on the polarization beam splitter 12G is reflected by the polarization splitting unit 12p disposed in a direction to reflect the incident S-polarized light, travels, and is a reflection type light disposed near the exit surface of the polarization beam splitter 12G. The light valve 16G is illuminated. Reflective light valve 16G
Is transmitted as P-polarized light through the polarization beam splitter 12G, passes through the cross dichroic prism 18 which is a color combining optical system, and is combined with other colors not described. The combined emission light is projected on a screen by the projection optical system 19.

In the case of the present invention, the polarizing beam splitter 1
Since the light is incident on the 2G through the polarizing device according to the present invention, the incident light does not include P-polarized light, and all the light incident on the polarizing beam splitter is not transmitted, but is all reflected and is a light valve. It is incident on 16G. Although only the G color light has been described here, the same applies to the R color light and the B color light.

Compared to the case where the device shown in FIG. 5 shown in the conventional example is applied to an illumination device of a reflection type light valve, the illumination brightness can be improved, and since there is no mixing of P-polarized light, a polarization beam splitter is used. There is no waste light that passes through, and the light does not become scattered light to generate a ghost image. Note that the polarizing device according to the present invention can be used for a similar projection display device having a configuration in which a transmission type light valve is arranged for each color light, and it is needless to say that a projection display device having a similar effect can be provided. Nor.

[0030]

As described above, in the light valve illuminating device using the polarizing device having the reflective layer according to the present invention, conventionally, discarded P-polarized light is converted into S-polarized light and is incident on the light valve. Thus, it is possible to achieve a high luminance illumination, and it is possible to achieve a great effect that a high luminance illumination by single linearly polarized light can be achieved even when the same light source as in the related art is used. In the present invention, since a so-called fly-eye integrator using the first lens plate and the second lens plate is used, the number of lenses of the first lens plate 2 depends on the number of lenses.
Since the superposed illumination of the light valve is performed, an effect of achieving uniform illumination can also be achieved.

Further, by employing a lighting device having the above-mentioned effects in a projection display device, it is possible not only to obtain a high-brightness color projection image but also to employ a so-called fly-eye integrator. , A projection image with uniform brightness can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a polarizing device and an illumination optical system according to first and second embodiments.

FIG. 2 is an explanatory diagram of a polarizing device that is a main part of the illumination device according to the first and second embodiments.

FIG. 3 is a configuration perspective view of a polarization device, which is a main part of the illumination device according to the first and second embodiments.

FIG. 4 is an explanatory diagram of a configuration of a projection display device when a reflective light valve according to a third embodiment is used.

FIG. 5 is an explanatory diagram of a configuration of a conventional light valve illumination optical system.

FIG. 6 is an explanatory view of a polarizing device which is a main part of a conventional light valve illumination optical system.

[Explanation of symbols]

Reference Signs List 1 light source 2 first lens plate 2a lens forming first lens plate 3 second lens plate 3a lens forming second lens plate 4 polarizing beam splitter forming polarizing beam splitter array 5 1/2 wavelength phase plate 6 Optical lens 7, 7 'Light valve 8 Light reflecting layer or light absorbing layer

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 5/74 H04N 5/74 A F term (reference) 2H042 AA04 AA18 AA26 2H088 EA14 EA15 EA16 EA18 HA13 HA15 HA20 HA21 HA23 HA24 HA25 HA28 MA04 MA06 2H099 AA12 BA09 CA01 DA05 5C058 AA06 AB05 BA05 BA35 EA02 EA11 EA12 EA26 5G435 AA02 AA03 BB12 BB15 BB16 BB17 DD14 FF03 FF05 FF07 GG01 GG02 GG03 GG04 GG08 GG28

Claims (2)

[Claims] 1. A lens plate having a plurality of lenses arranged in a plane, the first lens plate dividing a substantially parallel light beam emitted from a light source into a plurality of light beams by an aperture formed by the plurality of lenses. Another lens plate having a plurality of lenses in a plane,
A second lens plate in which the respective lenses are disposed at the focal positions of the plurality of lenses of the first lens plate and a plurality of polarization beam splitters disposed on the exit surface side of the second lens plate are planarly bonded. A polarizing beam splitter array, and a half wavelength for converting one of P-polarized light or S-polarized light emitted from the emission surface into the other polarization on an emission surface of the polarization beam splitter constituting the polarization beam splitter array. A phase plate; and a light reflection layer disposed between the exit surface of the second lens plate and the polarizing beam splitter array at a position corresponding to a boundary of a lens constituting the second lens plate. A polarizing device. 2. A light source which emits a substantially parallel light beam, and a lens plate on which a plurality of lenses are arranged in a plane, wherein the light source light emitted from the light source is transmitted to a plurality of light beams by an aperture formed by the plurality of lenses. A first lens plate divided into a plurality of lenses, and another lens plate having a plurality of lenses in a plane,
A second lens plate in which the respective lenses are disposed at the focal positions of the plurality of lenses of the first lens plate and a plurality of polarization beam splitters disposed on the exit surface side of the second lens plate are planarly bonded. A polarizing beam splitter array; and a light reflecting layer disposed between the exit surface of the second lens plate and the polarizing beam splitter array at a position corresponding to a boundary of a lens constituting the second lens plate. Polarizing device provided with: R (red), G (green), B
A color separation optical system for color separation into each color light of (blue), and R for image-modulating each color light separated by the color separation optical system.
A light valve for each color of G and B, a color synthesis optical system for synthesizing each color light modulated by the light valve, and a projection optical system for projecting the light synthesized by the color synthesis system as a projection image onto a screen. A projection display device, comprising: