JP2003330106A - Lighting device and projection display device - Google Patents

Abstract

(57) [Problem] To provide a small and lightweight lighting device and a projection display device. An illumination device used in a projection display device of the present invention includes an LED array that emits light of different colors, and a uniform illumination that emits light with uniform illuminance of incident light from the LED array. Means. The uniform illumination means has a function of narrowing the angular distribution of the incident light and making the illuminance distribution of the incident light uniform, and includes a plurality of rod lenses 8 provided with diffraction gratings on both the incident end face and the exit end face. Are constituted by a rod lens array 3 arranged in a plane or a curved surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting device and a projection type display device, and more particularly to a structure of a small and thin lighting device.

[0002]

2. Description of the Related Art Conventionally, there is known a projection type display device which synthesizes image light by using a light modulator such as a liquid crystal light valve and enlarges and projects the synthesized image light on a screen through a projection optical system including a projection lens. Has been. In a lighting device used for this type of projection display device, light emitted from a light source such as a metal halide lamp usually has a non-uniform illuminance distribution in which a central part is bright and a peripheral part is dark. Therefore, in order to uniformize the illuminance distribution in the illuminated area, specifically, the liquid crystal light valve, the illumination device for the projection display device has a fly-eye integrator composed of two fly-eye lenses or a rod-shaped guide. A uniform illuminating unit such as a rod integrator including an optical body (hereinafter, also referred to as a rod lens) is provided.

[0003]

The conventional projection type display device is provided with many optical systems such as a color separation optical system and a color synthesis optical system in addition to the above-mentioned illumination device, and the devices themselves compare with each other. It was very large. Therefore, in recent years, along with the widespread use of projection type display devices, there has been a demand for smaller and thinner devices.

Among the above uniform illumination means, the fly-eye integrator divides the incident light into a plurality of partial light fluxes by a plurality of lenses and superimposes these partial light fluxes on an illuminated area (liquid crystal light valve). This is to obtain illumination light with a uniform illuminance distribution. Therefore,
The distance between the two fly-eye lenses and the distance between the fly-eye integrator and the light valve need to be increased to some extent, which has been an obstacle to downsizing and thinning of the device. Further, in order to shorten the distance, it is necessary to make the eccentricity of the lens large, which makes it difficult to process the lens. Further, there is a problem that the boundary between the two fly-eye lenses causes unnecessary scattering.

On the other hand, the rod integrator makes the illuminance distribution uniform by repeating the internal reflection of the incident light a plurality of times in the rod lens, and the more the internal reflection of the incident light increases, the more Uniformized light is obtained. To increase the number of internal reflections of incident light,
It is necessary to reduce the diameter or length of the rod lens. However, reducing the diameter of the rod lens is limited by the size of the light source and the size of the light valve, which is the illuminated region, and cannot be made too small. Further, if the length of the rod lens is increased, the illuminating device becomes large, which is an obstacle to downsizing and thinning of the device.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a small and thin projection type liquid crystal display device, and an illumination device suitable for use in the same.

[0007]

In order to achieve the above-mentioned object, an illuminating device of the present invention is provided with a light source and a uniform illuminating means for making the illuminance of incident light from the light source uniform and emitting it. The apparatus is characterized in that the uniform illumination means includes a diffractive optical element having a function of narrowing an angular distribution of the incident light and uniformizing an illuminance distribution of the incident light.

Whereas the conventional uniform illuminating means comprises a fly-eye integrator or a rod integrator and in any case utilizes refraction by a lens, the uniform illuminating means of the present invention is provided with a diffractive optical element and the incident light It utilizes the diffraction phenomenon of. That is, in the case of the present invention, since the incident light is deflected by utilizing the diffraction by the diffractive optical element, the incident light can be easily bent at a larger angle than in the case where the refraction by the lens is used. as a result,
The illuminance distribution of incident light can be made uniform over a short distance, and the illumination device can be made smaller and thinner.

Further, the uniform illuminating means can spread the light source light emitted from a limited area at a wide angle up to the size of the diffractive optical element and emit the light at an angle nearly parallel to the optical axis. As described above, it has a function of narrowing the angular distribution of incident light. Thereby, for example, when adopted in a projection type display device, light can be made incident on the liquid crystal light valve from a direction close to the normal direction, and an effect of improving contrast can be obtained.

The diffractive optical element may be constituted by, for example, a rod-shaped light guide body having a diffraction grating provided on at least an incident end surface or a tubular light guide body having an inner surface or an outer surface as a reflecting surface. The "rod-shaped light guide" or "tube-shaped light guide whose inner surface or outer surface is a reflective surface"
Is a so-called conventional rod lens. Further, in the case of a tubular light guide, "the inner surface or the outer surface is a reflective surface" means that the place where the reflective surface is provided may be the inner surface or the outer surface of the tube, but in either case, the side where the light is reflected is the tube. It means inside. According to this structure, a diffractive optical element suitable for the uniform illumination means of the present invention can be easily manufactured only by providing a diffraction grating on the incident end surface of the rod lens.
Further, the deflection angle of the incident light can be easily adjusted by changing the pitch of the unevenness of the diffraction grating. With this configuration,
Processing of the diffractive optical element is not so difficult, and light scattering or loss does not occur inside the diffractive optical element.

In that case, it is desirable to provide a diffraction grating also on the exit end face side of the diffractive optical element. According to this configuration, the light that has been spread by the diffraction grating on the incident end face side to a relatively wide area on the emission end face can be deflected by the diffraction grating on the emission end face side to an angle nearly parallel to the optical axis.

The light guide may have the same diameter from the entrance end face side toward the exit end face side, but may have a tapered shape with a divergence. When the rod lens has a taper shape with a divergent shape, each time the light is reflected by the inner surface of the lens, the light is bent in a direction close to the optical axis, and thus light having an angle closer to parallel to the optical axis can be obtained.

The light source is, for example, a light emitting diode (hereinafter abbreviated as LED).
It is possible to use a planar light source in which a plurality of solid-state light emitting elements such as the above are arranged in a plane or curved shape. According to this configuration,
A small and thin lighting device can be easily realized.

The projection type display device of the present invention comprises the above-mentioned illumination device of the present invention, a light modulator for modulating the light from the illumination device, and a projection lens for projecting the light modulated by the light modulator. It is characterized by having.

According to this structure, since the lighting device of the present invention is provided, it is possible to realize a small and thin projection type display device. Further, since the illumination device emits light having a narrow angular distribution and a uniform illuminance distribution, it is possible to reproduce an image with high brightness and little unevenness in brightness.

Another projection type display device of the present invention is a planar light source in which a plurality of light sources capable of emitting color lights of different colors in a time-sequential manner are arranged in a plane or curved surface, and an incident light from the planar light source. Uniform illumination means having a diffractive optical element having a function of narrowing the angle distribution of light and making the illuminance distribution of the incident light uniform, and of each color light emitted from the light source through the uniform illumination means in time sequence. It is characterized in that it is provided with a light modulating means composed of a light valve which is time-divisionally driven in synchronization with the emission timing, and a projection lens for projecting the light modulated by the light modulating means.

This projection type display device employs a drive system called "color sequential drive system". Therefore, unlike the conventional three-panel projection type display device that uses three light valves for each color light, only one light valve is required (becomes a single-panel system), and an optical system for illuminating the light modulator. Only one system is required. Further, since the color separation optical system and the color synthesis optical system are unnecessary, the number of parts can be greatly reduced, the device configuration can be simplified, and the cost can be reduced.

Still another projection type display apparatus of the present invention is provided with a plurality of planar light sources capable of emitting color lights of different colors, and provided on each emission side of the plurality of planar light sources. A plurality of uniform illumination means having a function of narrowing the angular distribution of the incident light from the light source and uniformizing the illuminance distribution of the incident light, and provided on the emission side of each of the plurality of uniform illumination means. A plurality of light modulators each including a light valve that modulates each color light emitted from the light source through the uniform illuminating means; a color combiner that combines the color lights modulated by the plurality of light modulators; And a projection lens for projecting the light combined by the color combining means.

This projection type display device requires a plurality of light valves, unlike the above-mentioned device.
However, unlike the conventional device, a plurality of light sources are configured to emit color lights of different colors, and a light valve is provided for each color light, so that a color separation unit is not required. As a result, the device configuration becomes simpler than that of the conventional device. Further, since it is not necessary to synchronize the driving of the light source and the light valve as in the above-mentioned device, the driving is not complicated and the light valve does not need to have such a high response speed.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. In this embodiment mode, an example of a projection type color liquid crystal display device of a color sequential drive system is shown. FIG. 1 is a schematic diagram showing the overall configuration of a projection display apparatus 1, in which reference numeral 2 is an LED array (planar light source), 3 is a rod lens array (uniform illumination means), 4 is a PBS array, and 5 is A liquid crystal light valve (light modulator) 6 is a projection lens.

The projection type display device 1 of the present embodiment is shown in FIG.
As shown in FIG. 2, an LED array 2 in which a plurality of LEDs 7r, 7g, 7b (solid-state light-emitting elements) capable of emitting R, G, and B color lights are arranged in a plane or curved surface, and an LED 7r,
A rod lens array 3 in which a plurality of rod lenses 8 for equalizing the illuminance of each color light emitted from 7g and 7b are arranged in a planar shape or a curved surface, and a rod lens array 3
A PBS array 4 for converting the polarization of light incident from
A liquid crystal light valve 5 that modulates each color light incident from the PBS array 4 to synthesize an image, and a projection lens 6 that magnifies and projects the image synthesized by the liquid crystal light valve 5 onto a screen 9 are roughly configured. Among these, the illumination device of the present embodiment is composed of the LED array 2 and the rod lens array 3 shown in FIG.

The LED array 2 is connected to the light source drive circuit 10, and the light source drive circuit 10 causes the LEDs 7 to operate.
The timing at which r, 7g, and 7b emit light is controlled, and each L
From ED7r, 7g, 7b, for example, R, G, B, R, G,
B, ... The color light can be emitted in time sequence.

As shown in FIG. 2, the rod lens array 3 includes a plurality of rod lenses 8 (diffractive optical elements) each formed of a wedge-shaped glass column and arranged in a plane or curved shape corresponding to each LED 7r, 7g, 7b. It was done. In FIG. 2, the left side surface of the rod lens 8 is the incident end surface 8a, and the right side surface is the output end surface 8b. FIG. 3 is a sectional view showing one rod lens 8 taken out. Rod lens 8
Is a tapered shape that is divergent from the incident end face 8a side toward the emitting end face 8b side. The incident end face 8a and the emitting end face 8b are
Diffraction gratings 9a and 9b are respectively formed on both sides. The pitch of the grooves of the diffraction gratings 9a and 9b is, for example, large at the central portions of both end surfaces of the rod lens 8 and small at the peripheral portions. For example, the minimum pitch is about 1 μm and the maximum groove depth is about 0.35 μm. Also, each LED7
The r, 7g, 7b and each rod lens 8 do not necessarily have to correspond to 1: 1 and, for example, one rod lens may correspond to a plurality of LEDs.

The light emitted from each of the LEDs 7r, 7g, 7b has an illuminance distribution in which the illuminance at the center of the LED is high and the illuminance at the peripheral edge is low when the light reaches the incident end face of the rod lens array 3. There is. However, in the diffraction grating 9a on the incident end surface 8a of each rod lens 8, the light flux that hits the central portion of the LED is diffracted at a large angle so as to spread further outward. Then, the incident light is repeatedly reflected on the inner surface of the rod lens 8, and the illuminance is in a uniform state at the time of being emitted from the emission end surface 8b. Further, the light is diffracted by the diffraction grating 9b on the side of the emitting end face 8b to an angle nearly parallel to the optical axis and emitted.

That is, the diffraction grating 9a on the incident end face 8a side
And the diffraction grating 9b on the emitting end face 8b side have slightly different functions. The diffraction grating 9a on the incident end face 8a side mainly functions as an illuminance homogenizing means, while the diffraction grating 9b on the emission end face 8b side has a function as an angle conversion element so that light becomes closer to parallel. The narrowed angular distribution reduces the amount of light emitted by the projection lens and improves the light utilization efficiency. If the brightness of the light source is sufficiently high depending on the application, the diffraction grating may be sufficient only on the incident end face side.

In the case of this embodiment, the rod lens 8
Has a divergent tapered shape, so each time light is reflected on the inner surface of the lens, it can be bent in a direction close to the optical axis.
It is possible to obtain light having an angle closer to parallel to the optical axis.

The PBS array 4 is a combination of a plurality of PBSs having a polarization separation film 4a and a reflection film 4b and a ½ wavelength plate 4c (phase difference plate). One of the p-polarized light and the s-polarized light (linearly polarized light) included in (1) is converted into the other polarized light. Therefore, the positional relationship between the LEDs 7r, 7g, 7b and the PBS array 4 is so arranged that the light emitted from the LEDs 7r, 7g, 7b first enters the polarization separation film 4a.

The liquid crystal light valve 5 includes a thin film transistor as a pixel switching element.
or, hereinafter, abbreviated as TFT), a TN mode active matrix transmissive liquid crystal cell 31 is used, and an incident side polarizing plate 32 and an outgoing side polarizing plate 33 are transmitted to the outer surface of the liquid crystal cell 31. The axes are arranged so as to be orthogonal to each other. For example, in the off state, the s-polarized light incident on the liquid crystal light valve 5 is converted into p-polarized light and emitted, while in the on-state, the light is blocked. The LED array 2, the rod lens array 3, the PBS array 4, and the liquid crystal light valve 5 may be arranged separately from each other, but in order to reduce the size and thickness of the device, they may be arranged in close contact with each other. desirable.

As shown in FIG. 1, the liquid crystal light valve 5 is connected to a liquid crystal light valve drive circuit 11, and the liquid crystal light valve drive circuit 11 causes the liquid crystal light valve 5 to correspond to each incident color light. It has a structure that can be driven sequentially in time. Further, in the projection display device 1 of the present embodiment, the synchronization signal generation circuit 1
2 is provided, and the synchronization signal SYNC is generated by the synchronization signal generation circuit 12 and is input to the light source drive circuit 10 and the liquid crystal light valve drive circuit 11 to emit colored light from the LEDs 7r, 7g, 7b. The structure is such that the timing and the timing of driving the liquid crystal light valve 5 corresponding to the colored light can be synchronized.

That is, in the projection display apparatus 1 of this embodiment, one frame is time-divided and the LEDs 7r, 7g, 7
Each of the R, G, and B color lights is emitted sequentially from b to L
By synchronizing the timing of emitting the colored light from the ED 7r, 7g, 7b and the timing of driving the liquid crystal light valve 5, the liquid crystal light valve 5 is time-sequentially corresponded to the colored light emitted from the LEDs 7r, 7g, 7b. By driving and outputting an image signal corresponding to the color light emitted from each of the LEDs 7r, 7g, 7b, a color image can be combined.

The projection type display device of the present embodiment employs a driving method called a so-called "color sequential driving (color sequential) method". Therefore, unlike the conventional three-panel type projection display device that uses three liquid crystal light valves for each color light, only one liquid crystal light valve is required (it becomes a single plate type), and the light modulation means is illuminated. Only one optical system is required. Further, since the color separation optical system and the color synthesis optical system are unnecessary, the number of parts can be greatly reduced, the device configuration can be simplified, and the cost can be reduced.

Particularly, in the rod lens array 3, since the incident light is deflected by utilizing the light diffraction phenomenon by the diffraction gratings 9a and 9b, the incident light can be easily made at a large angle as compared with the case where a simple rod lens is used. Can be bent. As a result, the illuminance distribution of the incident light can be made uniform over a short distance, and the illumination device can be made smaller and thinner, and thus the projection display device can be made smaller and thinner. Also,
By the action of the rod lens array 3, light having a narrow angle distribution and a uniform illuminance distribution is emitted from the illuminating device, so that it is possible to reproduce a high-contrast image with less uneven brightness.

In the present embodiment, the incident end face 8a,
Although the rod lens array 3 is configured by using only the tapered rod lens 8 in which the diffraction gratings 9a and 9b are provided on both the exit end faces 8b, the rod lens array as shown in FIG. 4 is used instead of this configuration. May be. That is, in the rod lens array 21 shown in FIG. 4, a rod-shaped rod lens 22 having the same diameter is further connected to the exit end face 8b side of the rod lens array 3 shown in FIG. 2 on the entrance end face 22a side and the exit end face 22b side. It has a configuration. According to this configuration,
Even if the rod lens array 3 shown in FIG. 2 is thin, if the uniformity of the illuminance distribution and the reduction of the angular distribution are still insufficient, the action of the added rod lens array 21 increases the thickness of the illuminating device. It is possible to further improve the function of making the illuminance distribution uniform.

[Second Embodiment] The second embodiment of the present invention will be described below.
Embodiments will be described with reference to FIGS. The basic structure of the projection type display device of this embodiment is exactly the same as that of the first embodiment, and only the structure of the rod lens array (uniform illumination means) is different. Therefore, the description of the entire projection type display device will be omitted, and only the rod lens array will be described.

In the first embodiment, the rod lens array is composed of tapered rod lenses, whereas in the present embodiment, as shown in FIG. 5, the incidence end face side and the emission end face side are the same. The rod lens array 50 is configured using rod-shaped rod lenses 51 having a diameter. That is, the rod lens array 50 according to the present embodiment includes a plurality of rod lenses 51 (diffractive optical elements) each formed of a glass column and each LED 7
It is arranged in a plane or curved shape corresponding to r, 7g, and 7b. In FIG. 5, the left side surface of the rod lens 51 is the incident end surface 51a, and the right side surface is the emission end surface 51b.

FIG. 6 is a sectional view showing one rod lens 51 taken out. Incident end face 51 of rod lens 51
Diffraction gratings 52a and 52b are formed on both a and the emission end face 51b. In this embodiment also, each L
The EDs 7r, 7g, 7b and the rod lenses 51 do not necessarily have to correspond to each other in a ratio of 1: 1.
One rod lens may correspond to D.

The light emitted from each of the LEDs 7r, 7g, 7b has an illuminance distribution in which the illuminance at the central portion of the LED is high and the illuminance at the peripheral portion is low when the light reaches the incident end surface of the rod lens array 50. There is. However, in the diffraction grating 52a of the incident end surface 51a of each rod lens 51,
The light flux that hits the central portion of the LED is diffracted at a large angle so as to spread outward. Then, the incident light is repeatedly reflected on the inner surface of the rod lens 51, and the illuminance is in a uniform state at the time of being emitted from the emission end surface 51b.
Further, the light is diffracted by the diffraction grating 52b on the side of the emitting end face 51b to an angle nearly parallel to the optical axis and emitted.

Instead of the simple grooved diffraction gratings 52a and 52b shown in FIG. 6, blazed diffraction gratings 53a and 53b may be provided as shown in FIG. 7, for example. In this case, since the diffracted light can be concentrated on a specific order, it is easy to control the light, that is, make the illuminance distribution of the light uniform.

[Third Embodiment] The third embodiment of the present invention will be described below.
The embodiment will be described with reference to FIGS. 8 and 9. In the first and second embodiments, the example in which the rod lens array is used as the uniform illuminating means is given, but in the present embodiment, an example in which the rod lens array is not used in the uniform illuminating means will be described.

In this embodiment, instead of the rod lens having the diffraction grating described in the first and second embodiments, as shown in FIG. 8, two diffraction gratings 54a are used without using the rod lens. , 54b alone to form a uniform illumination means as a space between them. Further, as shown in FIG. 9, diffraction gratings 56a and 56b may be provided on the curved surfaces of each of the two lenses 55, and the diffraction gratings 56a and 56b may be blazed. Also in the present embodiment, by providing the uniform illuminating unit having the above-described configuration, it is possible to achieve the function of narrowing the angle distribution of incident light and making the illuminance distribution of light uniform.

[Fourth Embodiment] The fourth embodiment of the present invention will be described below.
The embodiment will be described with reference to FIG. This embodiment is also an example of a projection type color liquid crystal display device,
While the third embodiment is an example of a single plate system of color sequential driving system, this embodiment shows an example of a three plate system.
FIG. 10 is an enlarged view showing the schematic configuration of the projection display device. In FIG. 10, the same components as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the first embodiment, the light source is R,
LEDs 7r, 7 capable of emitting colored lights of different colors G and B
While the LED array 2 in which g and 7b are arranged in the same plane is used, in the projection type liquid crystal display device 36 of the present embodiment, as shown in FIG. 10, LEDs capable of emitting R color light are used.
LED array 2r having 7r arranged in the same plane, LED array 2g having LED 7g capable of emitting the colored light of G arranged in the same plane, LED array 2b having LED 7b capable of emitting the colored light of B arranged in the same plane, 3 are used as planar light sources. Then, each LED array 2r, 2g, 2b
A rod lens array 3 including a rod lens 8 having diffraction gratings 9a and 9b (not shown in FIG. 10) similar to those used in the first embodiment is arranged on the emission side of. The LED array 2r, 2g, 2b for each color light and the rod lens array 3 constitute the illumination device of the present embodiment. Therefore, the projection type display device of the present embodiment has three illumination devices for each color light.

PBS is provided on the exit side of each rod lens array 3.
An array 4 is provided, and a liquid crystal light valve 5 that modulates each color light of R, G, and B is also provided. The three color lights modulated by each liquid crystal light valve 5 are configured to enter the cross dichroic prism 25 (color combining unit). This prism 2
5 is the one in which four right angle prisms are pasted together,
A dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in a cross shape on the inner surface. The three color lights Lr, Lg, and Lb are combined by these dielectric multilayer films to form light representing a color image. The color-combined light is projected on the screen 9 by the projection lens 6,
The enlarged image is displayed.

The projection type display device of this embodiment is different from the device of the first embodiment in that it has three liquid crystal light valves 5.
Is what you need. However, unlike the conventional device, the three lighting devices are configured to emit colored lights of different colors, and the liquid crystal light valve 5 is provided for each colored light.
Is provided, there is no need for color separation means such as the dichroic mirror in the conventional device. As a result, the device configuration becomes simpler than that of the conventional device. Also,
As in the device of the first embodiment, the LED arrays 2r, 2
Since it is not necessary to synchronize the driving of g and 2b with the liquid crystal light valve 5, the driving is not complicated, and the liquid crystal light valve does not need to have a high response speed.

Also in this embodiment, since the rod lens array 3 having the diffraction grating is used, it is possible to easily bend the incident light at a larger angle than when a simple rod lens is used. It is possible to make the illuminance distribution of the incident light uniform over a distance, which makes it possible to reduce the size and thickness of the lighting device, and thus the projection type display device to a smaller size and thickness. The same effect as that of the first embodiment can be obtained.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the diffractive optical element used in the uniform illuminating means of the present invention may be any element that deflects the incident light by using the diffraction phenomenon of the incident light. For example, in addition to the rod lens having the diffraction grating used in the above embodiment, a lens having a diffraction grating formed on a flat surface or a curved surface can be used.
Further, although general examples are given as the optical components used for the polarization converting means, the light modulating means, the color synthesizing means, and the like, as long as they have the above-mentioned functions, those of the above-mentioned embodiments can be used. Other selections may be made as appropriate. In applications where brightness is not important, the polarization conversion means may be omitted.
Further, as the configuration of the projection type display device, the arrangement of the uniform illuminating means and the polarization converting means may be opposite to that of the above embodiment. In the above embodiment, an example in which the illumination device of the present invention is used for the projection type display device is shown, but it is also possible to use it for the direct view type display device.

[0047]

As described above in detail, according to the present invention, since the incident light is deflected by utilizing the diffraction by the diffractive optical element in the uniform illuminating means, a larger angle than that when a simple lens is used. Thus, the incident light can be easily bent, the illuminance distribution of the incident light can be made uniform over a short distance, and the illumination device can be downsized and thinned. Then, by adopting this illuminating device, a small and thin projection type display device can be realized. Further, since the illumination device emits light having a narrow angular distribution and a uniform illuminance distribution, it is possible to reproduce an image with high brightness and little unevenness in brightness.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a projection display device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of an illumination device that constitutes the projection display device.

FIG. 3 is a cross-sectional view showing one rod lens including a diffraction grating that constitutes the illuminating device.

FIG. 4 is a cross-sectional view showing a modified example of the lighting device.

FIG. 5 is a cross-sectional view showing a configuration of an illumination device that constitutes a projection display device according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view showing one rod lens including a diffraction grating that constitutes the illumination device.

FIG. 7 is a sectional view showing a modification of the rod lens of the same.

FIG. 8 is a sectional view showing a structure of a uniform illuminating means according to a third embodiment of the present invention.

FIG. 9 is a sectional view showing a modified example of the uniform illumination means.

FIG. 10 is a schematic configuration diagram showing a projection display device according to a fourth embodiment of the present invention.

[Explanation of symbols]

1, 36 Projection type display device 2 LED array (planar light source) 3,50 Rod lens array (uniform illumination means) 4 PBS array 5 Liquid crystal light valve (light modulation means) 6 Projection lens 7r, 7g, 7b LED (light source) 8, 22, 51 Rod lens 9 Screen 9a, 9b, 52a, 52b, 53a, 53b, 54
a, 54b, 56a, 56b Diffraction grating 25 Cross dichroic prism (color combining means)

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G02B 19/00 G02F 1/13 505 2H099 27/28 1/133 520 2K103 G02F 1/13 505 1/1335 3K042 1/133 520 1/13357 1/1335 F21Y 101: 02 1/13357 F21M 1/00 R // F21Y 101: 02 F term (reference) 2H049 AA04 AA14 AA60 AA64 2H052 BA02 BA09 BA14 2H088 EA12 EA13 EA14 EA47 EA48 HA06 HA08 HA13 HA15 HA18 HA21 HA23 HA24 HA25 HA28 HA30 JA05 MA02 MA20 2H091 FA05X FA05Z FA07X FA07Z FA11Z FA14Z FA19X FA19Z FA23Z FA26X FA41Z FA45Z GA11 GA13 HA07 LA11 LA17 LA30 MA07 2H093 NA63 NA64 NA65 NC16 NC41 NC43 ND04 ND42 ND54 NF05 2H099 AA11 BA09 CA02 CA08 DA05 2K103 AA05 AB07 BA02 BC20 BC42 3K042 AA01 AC06 BA09 BE02

Claims (8)

[Claims] 1. An illuminating device comprising a light source and a uniform illuminating means for equalizing and emitting illuminance of incident light from the light source, wherein the uniform illuminating means narrows an angular distribution of the incident light. An illuminating device comprising a diffractive optical element having a function of making the illuminance distribution of the incident light uniform. 2. The diffractive optical element comprises a rod-shaped light guide body having a diffraction grating provided on at least an incident end surface or a tubular light guide body having an inner surface or an outer surface as a reflecting surface. The lighting device according to 1. 3. The illumination device according to claim 2, wherein a diffraction grating is also provided on the exit end face side of the diffractive optical element. 4. The illuminating device according to claim 2, wherein the light guide body has a tapered shape that is divergent from the incident end face side toward the emitting end face side. 5. The lighting device according to claim 1, wherein the light source is a planar light source in which a plurality of solid state light emitting elements are arranged in a plane or a curved surface. 6. The lighting device according to claim 1, a light modulator for modulating light from the lighting device, and a projection lens for projecting light modulated by the light modulator. And a projection type display device. 7. A planar light source in which a plurality of light sources capable of temporally sequentially emitting colored lights of different colors are arranged in a plane or curved surface, and an angle distribution of incident light from the planar light source is narrowed, and Uniform illumination means having a diffractive optical element having a function of making the illuminance distribution of incident light uniform, and time-division driving in synchronization with the emission timing of each color light emitted from the light source through the uniform illumination means in time sequence. And a projection lens for projecting the light modulated by the light modulating means. 8. A plurality of surface light sources capable of emitting color lights of mutually different colors, and provided on each emission side of each of the plurality of surface light sources to narrow the angular distribution of incident light from each surface light source, And a plurality of uniform illuminating means provided with a diffractive optical element having a function of making the illuminance distribution of the incident light uniform, and provided on each emission side of the plurality of uniform illuminating means, the uniform illuminating means from the light source. A plurality of light modulation means consisting of a light valve for modulating each color light emitted through, and a color combination means for combining the color light modulated by the plurality of light modulation means,
A projection type display device, comprising: a projection lens that projects the light combined by the color combining unit.