JP2002244211A - Image projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide new lighting technology which actualizes both high light use efficiency and a small-sized optical system, with respect to an image projection device using a liquid crystal panel which uses light emitting diodes as light sources and modulates polarized light. SOLUTION: The LED light sources 101 to 103 composed of light emitting diodes corresponding to light sources of red, green, and blue and are so constituted as to put the three color lights by a dichroic prism 121 and lighten up a liquid crystal light valve 131. Polarized light converting elements 111 to 113 functions to polarize the lights emitted by the light emitting diodes so that the liquid crystal light valve is lit up. A polarizing beam splitter 131 functions as a polarizer which make uniform the polarized lights made incident on the liquid crystal light valve and also functions as an analyzer for projection lights. The light modulated by the liquid crystal light valve 141 is projected on a screen 161 by a projection lens 151.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a projection type image display device, and more particularly to an image projection device using a light emitting diode as a light source.

[0002]

2. Description of the Related Art In a conventional projection display device, a discharge lamp such as a high-pressure mercury lamp or a metal halide lamp is generally used as a light source. The light from the light source is guided to a light valve such as a liquid crystal, and the light modulated by the light valve is guided to a projection lens as projection light and projected on a screen. However, such a discharge lamp is large, and there is a problem that the size of the entire optical system becomes large.

Further, since the above-mentioned lamp emits white light, in order to perform color display, the lamp is separated into three colors.
A method has been adopted in which a light valve is provided for each color light, and the light modulated by the light valve is combined again and guided to a projection lens. Therefore, there has been a problem that the optical system is further increased for the purpose of spectroscopy and synthesis.

[0004] As another method, there is also known a method of performing modulation using a single liquid crystal light valve provided with a color filter without performing spectroscopy. However, since the number of pixels of the light valve is limited, this method requires three light valves.
The number of pixels is reduced to 1/3 compared to the method using
There is a problem that high-definition display cannot be performed.

On the other hand, a projection type display device using a light emitting diode (LED) as a light source has recently been proposed. Since the light emitting diode itself is small, there is a possibility that a small device can be realized. In addition, the light emitting diode can be switched on and off instantly,
There is also an advantage that display in a so-called filled sequential system is possible. This is to sequentially turn on the LEDs of three colors RGB using one light valve, and to switch the light valve in synchronization with it. According to this method, color display can be performed by one light valve without lowering the resolution.

In an image projection apparatus using a liquid crystal panel as a modulation element, the liquid crystal panel forms an image by modulating the polarization state of incident light. Therefore, a polarizer such as a polarizing plate or a polarizing beam splitter is used between the liquid crystal panel and the light source. Since the illumination light is generally non-polarized light, if it is illuminated as it is, more than half of the light is lost by the polarizer. Therefore, in a recent apparatus, a polarization conversion element is provided between a light source and a light valve to convert illumination light into only desired polarized light.

FIG. 9 is a configuration diagram showing a typical example of the structure of a conventional polarization conversion element as described above. The polarization conversion element includes a polarization beam splitter 241 and an optical path changing unit 242 such as a mirror for making one polarized light separated by the polarization beam splitter parallel to the optical axis of the other polarized light;
A phase difference plate 243 is provided in the optical path of one polarized light and changes the plane of polarization by 90 ° with respect to the incident light. In the configuration of FIG. 9, as can be seen from the figure, one width of the light beam is doubled. This increases the optical path length for reducing the light flux to the size of the light valve, and increases the size of the entire optical system.

FIG. 10 is a configuration diagram showing a configuration example of another conventional polarization conversion element. The polarization conversion element array 240 has a structure in which a plurality of polarization conversion elements shown in FIG. 9 are arranged as one unit. This polarization conversion element array has a fly-eye integrator optical system 292,2 as shown in FIG.
93 used in combination with the second fly-eye lens 2
By providing the beam near 93 at the narrowed portion,
This is to increase the efficiency of capturing light rays and to perform polarization conversion without expanding the beam diameter. For this reason, a small and highly efficient image projection device can be realized.

[0009]

On the other hand, since a light emitting diode alone has insufficient luminance as a light source of a projection display device, it is necessary to arrange a plurality of light emitting diodes. In such a configuration of the multi-light source 201 of light emitting diodes, as shown in FIG.
When the polarization conversion element 3 and the polarization conversion element 240 are combined, light from different light sources cannot be accurately converged on the polarization beam splitter of the polarization conversion element, thereby causing a loss of light amount due to shaking or the like. Thus, in a system using a discharge lamp and a polarization conversion element,
When the light source is a light emitting diode light source, it has been difficult to achieve both high light use efficiency and a small optical system.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and provides an image projection apparatus using a light-emitting diode as a light source and a liquid crystal panel that modulates polarization to achieve high light use efficiency and a small optical system. It aims to provide a new lighting technology that is compatible with both.

[0011]

According to a first aspect of the present invention, there is provided a light source comprising a plurality of light emitting diodes, a liquid crystal light valve which is illuminated by light from the light source and modulates a polarization state of the incident illumination light. An image projection apparatus comprising: a projection lens for projecting light emitted from the liquid crystal light valve; and a polarization conversion element array for individually performing polarization conversion on light emitted from each of the light emitting diodes. It was done.

According to a second aspect of the present invention, in the first aspect of the present invention, a lens is provided in an optical path of each of the light emitting diodes so that light emitted from each of the light emitting diodes converges, and the polarization conversion element is provided. The array is provided near the convergence point where the emitted light converges, corresponding to the arrangement of the light emitting diodes.

According to a third aspect of the present invention, in the first aspect of the present invention, the polarization conversion element array is provided in an optical path near the light emitting diodes and in which beams emitted from the light emitting diodes do not substantially intersect. It is characterized by being arranged.

According to a fourth aspect of the present invention, in the second aspect of the invention, there is provided a lens for converging light emitted from the light emitting diode,
And the polarization conversion element array is disposed in the vicinity of the light emitting diodes and in an optical path in which beams emitted from the respective light emitting diodes do not substantially intersect.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, a lens array is provided in the divergent light path near the polarization conversion element, for converting the light beam into substantially parallel light. It was done.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the plurality of light emitting diodes are two-dimensionally arranged, and a plurality of light emitting diodes are arranged between the plurality of light beams emitted from the polarization conversion element array. Are substantially equal in the vertical and horizontal directions.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the aspect ratio of the arrangement pitch of the light emitting diodes is set to about 2, and the arrangement direction of the polarization conversion elements is changed to a direction in which the arrangement pitch of the light emitting diodes is longer. It is characterized by being adapted to.

According to an eighth aspect of the present invention, in the sixth aspect of the present invention, the aspect ratio of the arrangement pitch of the light emitting diodes is made substantially equal, and the arrangement direction of the polarization conversion element is made approximately 45 degrees from the arrangement direction of the light emitting diodes. It is characterized by being arranged at an angle of °.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the polarization conversion element array includes:
The device is characterized in that a unit element including a polarizing beam splitter, a light beam reflecting element, and a half-wave plate is arranged.

According to a tenth aspect of the present invention, in the light emitting device according to any one of the first to ninth aspects, a light source in which light emitting diodes having the same color are arranged as one light source array, The liquid crystal light valve is illuminated by combining light from an array.

According to an eleventh aspect of the present invention, in the tenth aspect of the present invention, the multicolor display is performed by sequentially switching the light emission of the plurality of light source arrays and operating the liquid crystal light valve in synchronization with the switching. It is characterized by performing.

[0022]

(Embodiment 1) FIG. 1 is a schematic diagram showing an entire configuration of an embodiment of an image projection apparatus according to the present invention. In FIG. 1, 101 to 103 are light sources (LED light sources) including a plurality of light emitting diodes, 111 to 113 are polarization conversion elements, 121 is a dichroic prism, 131
Denotes a polarizing beam splitter, 141 denotes a reflection type liquid crystal light valve, 151 denotes a projection lens, and 161 denotes a screen. In this embodiment, the light-emitting diodes 101 to 103 correspond to blue, green, and red light sources, respectively, and combine three color lights with the dichroic prism 121 to form a liquid crystal light valve 141.
Is configured to be illuminated. Polarization conversion elements 111-
Reference numeral 113 functions to align light emitted from the light emitting diode to a polarization state for illuminating the liquid crystal light valve.

The polarizing beam splitter 131 functions not only as a polarizer for aligning the polarized light incident on the liquid crystal light valve 141 but also as an analyzer for the emitted light. This configuration is an example. For example, the light emitting diode group of the light source is one unit, the dichroic prism is omitted, or a transmissive liquid crystal light valve is used as shown in FIG. 4, and a polarizing plate is used instead of the polarizing beam splitter. 142 and 143 can also be used. In addition, a field lens for expanding or reducing the illumination light, an integrator optical system for equalizing the illumination light, or the like is inserted between the polarization conversion elements 111 to 113 and the liquid crystal light valve 141 as necessary. You can also.

FIG. 2 is a schematic diagram showing a first configuration example of the illumination unit of the image projection device according to the present invention. A lens 20 for controlling the spread of the emitted light is formed on the front surface of the arranged light emitting diodes 11 to 15. Reference numeral 40 denotes a polarization conversion element, which includes a polarization beam splitter 41, an optical path changing element 42 including a mirror and a polarization beam splitter, and a half-wave plate 43. The polarization conversion element is provided corresponding to each light emitting diode, and is configured to individually convert a beam from each light emitting diode.

As described above, each of the light emitting diodes 11 to 1
By providing the polarization conversion element 40 before the light beams from 5 intersect, loss of light amount due to the boundary of the polarization conversion element 40 can be prevented, and a highly efficient illumination system can be constructed. Generally, it is difficult to make the emitted light from the light emitting diode completely parallel. To provide the polarization converting element 40 before the light beams from the light emitting diodes 11 to 15 intersect as in the present invention, the polarization converting element 40 must be provided. It is preferably provided immediately after the light emitting diode. In FIG. 2, it is preferable that the light emitting diodes 11 to 15 are also arranged in a direction perpendicular to the paper surface.

(Embodiment 2) FIG. 3 is a schematic diagram showing a second configuration example of the illumination section of the image projection apparatus according to the present invention. Lenses 20 and 30 for controlling the spread of emitted light are formed on the front surfaces of the arranged light emitting diodes 11 to 15. Reference numeral 40 denotes a polarization conversion element. In this embodiment, the light emitted from the light emitting diodes 11 to 15 is
It is configured to converge by 0 and 30. A polarization conversion element array 40 is provided near the convergence point in correspondence with the arrangement of the light emitting diodes 11 to 15.

By adopting the above-described configuration, similarly to the first embodiment, it is possible to prevent a light quantity loss due to the boundary of the polarization conversion element 40 and to construct a highly efficient illumination system. Further, by providing the polarization conversion element 40 in the vicinity of the converging portion, the pitch of the polarization conversion element 40 can be reduced to about 、, and the spread of the beam can be suppressed.
This makes it possible to reduce the size of the entire illumination system.

In the configuration of FIG. 3, two lenses 2
Although the converging optical system is constituted by the set of 0 and 30, it is also possible to constitute the converging optical system only by the lens 20, for example. In general, it is difficult to make the light emitted from the light emitting diode completely parallel.
In order to converge the light beams before the light beams from to 15 intersect and guide the light beams to the polarization conversion element 40, it is preferable to provide the focusing lenses 20, 30 and the polarization conversion element 40 immediately after the light emitting diodes.

In FIG. 3, reference numeral 50 denotes a microlens array, which has a function of converting a divergent light beam emitted from the polarization conversion element 40 into a substantially parallel light beam. Further, the microlens array 50 may be located before the polarization conversion element 40. More preferably, the lens array 50 is provided to suppress the spread of the light beam and to reduce the size of the optical system. Further, as in the first embodiment, it is preferable that the light emitting diodes 11 to 15 are also arranged in a direction perpendicular to the paper surface.

(Embodiment 3) FIG. 5 is a schematic diagram showing a configuration example in which the uniformity of illuminance is improved in the image projection apparatus according to the present invention. FIG. 5 illustrates the relationship between the polarization conversion element array and the arrangement of the light emitting diodes when the polarization conversion element is viewed from the emission side. In FIG. 5, reference numeral 40 denotes a polarization conversion element array.
0a are arranged. The pitch of the arrangement of the light emitting diode arrays differs vertically and horizontally, and in this example, the vertical direction is arranged at twice the pitch. The arrangement direction of the polarization conversion element array 40 (the direction adjacent to the polarization conversion element) matches the long pitch direction of the light emitting diodes.

In this embodiment, of the light emitted from the photodiode, the light transmitted through the polarizing beam splitter is 10%.
The light emitted from the position a and the reflected light of the polarization beam splitter are emitted from the position 10b. That is, the emission positions are uniformly distributed, and the uniformity of the surface illuminance of the light emitted from the polarization conversion element, that is, the uniformity of the illuminance of the projected image can be improved.

(Embodiment 4) FIG. 6 is a schematic diagram showing another configuration example in which the uniformity of the illuminance is improved in the image projection apparatus according to the present invention. FIG. 6 illustrates the relationship between the polarization conversion element array and the arrangement of the light emitting diodes when viewed from the emission side of the polarization conversion element. In FIG. 6, reference numeral 40 denotes a polarization conversion element array, on the back surface of which light emitting diodes 10a are arranged. The aspect ratio of the arrangement pitch of the light emitting diodes is set substantially equal, and the polarization conversion element 4
The arrangement direction of 0 is arranged so as to form an angle of approximately 45 ° with the arrangement direction of the light emitting diodes 10a.

With the above-described configuration, the reflected light of the polarization beam splitter in the polarization conversion element is reflected by the adjacent four light beams.
The light is emitted from the center of the square formed by the centers of the two light emitting diodes, and the emission positions are uniformly distributed, so that the surface illuminance of the light emitted from the polarization conversion element is uniform, that is, the illuminance uniformity of the projected image Can be improved.

FIG. 7 is a diagram for explaining a preferred arrangement of the phase difference plate in the configuration shown in FIG. The strip-shaped retardation plate 43 is arranged so as to form an angle of 45 ° with the direction of the arrangement of the polarization conversion elements. The phase difference plate 43 is provided on either the optical path of the transmitted light or the reflected light of the polarization beam splitter of the polarization conversion element. With such a configuration, even when the arrangement direction of the light emitting diode and the polarization conversion element is inclined, the retardation plate can be easily arranged at a corresponding position.

(Embodiment 5) FIG. 8 is a diagram for explaining a preferred example for performing high-definition color display in the configuration of FIG. A microlens array 171 composed of a convex lens is provided between the blue LED light source 101 and the polarization conversion element 111, and a second microlens array 181 is provided between the polarization conversion element 111 and the dichroic prism 121. I have. Green LE in the same way
The D light source 102 and the red LED light source 103 are also provided with microlens arrays 172, 173 and first and second microlens arrays 182, 183, respectively, and constitute an optical system as shown in FIG.

The substantially parallel lights that have exited the microlens arrays 181 to 183 are color-combined by the dichroic prism 121, and enter the polarization beam splitter 131. A lens 191 provided between the polarizing beam splitter 131 and the dichroic prism 121 is a field lens for reducing the size of the light source to the size of the liquid crystal light valve 141, and includes a micro lens 192,
193 is an integrator optical system for equalizing the illumination light on the liquid crystal light valve.

In FIG. 8, reference numeral 141 denotes a reflection-type liquid crystal light valve, which is configured to be illuminated with S-polarized light from the polarization beam splitter 131 in this embodiment. Therefore, the polarization conversion elements 111 to 113 are also configured to enter the polarization beam splitter 131 as S-polarized light. The light reflected by the liquid crystal light valve 141 and modulated so that the plane of polarization is rotated passes through the polarization beam splitter 131 and is projected on the screen 161 via the projection lens 151.

In the structure of this embodiment, the number of the liquid crystal light valves 141 is one as shown in the figure. In order to perform color display in such a structure, the light emitting diodes are sequentially turned on, and the light valves are synchronized with the light valves. 141
Modulation. That is, when the blue light is on, a blue image is displayed, and similarly for red and green, lighting of the light emitting diode and modulation by the light valve are performed with a time lag.

In this embodiment, the liquid crystal light valve has one
Since only a single sheet is used and the size of the illumination optical system is smaller than that of a conventional optical system that performs spectroscopy using a discharge lamp, there is an advantage that the size of the entire optical system can be designed to be small. Furthermore, the illumination system using the polarization conversion optical system according to the present invention has a high efficiency, so that the number of light emitting diodes to be used can be reduced, so that there is an advantage that a more compact illumination system can be configured. Since such a field sequential system requires high-speed switching characteristics, a liquid crystal light valve using a ferroelectric liquid crystal is particularly preferably used.

In the above description, the configuration of the illumination system of the present invention in which the light emitting diode and the polarization conversion element are combined and the polarization conversion is performed before the light emitted from each light emitting diode array intersects has been described with reference to FIGS. However, the present invention is not limited to this. For example, a plurality of light emitting diodes of a plurality of colors may be arranged in one lighting unit, and the polarization conversion optical system may be used in combination with the one lighting unit. In addition, as the light emitting diode, a plurality of units can be used side by side, or a light emitting diode formed in advance as an array can be used.

As the liquid crystal light valve, either a transmission type or a reflection type can be used. In the embodiment, the case of using a dichroic prism has been described with respect to color synthesis, but a configuration such as a combination of a cross dichroic mirror and a dichroic mirror can be adopted.

[0042]

According to the present invention, there is provided an image projection apparatus comprising a light source comprising a plurality of light emitting diodes, a liquid crystal light valve illuminated by light from the light source and modulating the polarization state of incident light, and a projection lens. It is characterized by providing a polarization conversion element array that individually converts the polarization of the light emitted from the diode.With such a configuration, it is possible to guide the light emitted from the light emitting diode to the polarization conversion element without loss, A highly efficient image projection device can be realized.

Further, a lens is provided in the light path of the light emitted from each light emitting diode so that the light emitted from each light emitting diode converges, and a polarization conversion element array is provided near the convergence point in correspondence with the arrangement of the light emitting diodes. In the image projection apparatus according to the present invention, since the emitted light can be guided to the polarization conversion element more efficiently, an image projection apparatus with higher efficiency can be realized.

Further, a lens or a polarization conversion element array for converging the light emitted from the light emitting diode is disposed near the light emitting diode and in an optical path where the light beams emitted from the respective light emitting diodes do not substantially intersect. In an image projection apparatus in which the element array is located in the vicinity of the light emitting diodes and is arranged in an optical path where the emitted beams from the respective light emitting diodes do not substantially intersect, the polarization conversion element is used in a state where the emitted lights from the light emitting diodes are not mixed. Therefore, the emitted light beam can be guided to the polarization conversion element without being shaken, so that an even more efficient image projection device can be realized.

Further, in an image projection apparatus characterized in that a lens array for converting light rays into substantially parallel light is provided in a divergent light path near the polarization conversion element, the spread of light emitted from the polarization conversion element can be suppressed. Therefore, the optical system can be designed to be small, and the entire device can be configured to be small.

Further, in an image projection apparatus characterized in that light emitting diodes are two-dimensionally arranged and the pitch between light beams emitted from the polarization conversion element array is substantially equal in the vertical and horizontal directions. The intensity distribution can be made more uniform, and an image projection device with higher display uniformity can be realized.

Further, the aspect ratio of the arrangement pitch of the light emitting diodes is set to about 2, and the arrangement direction of the polarization conversion elements is adjusted to the long direction of the pitch of the light emission diodes. It is an object of the present invention to provide a preferable novel realizing means in which the pitch between the light beams emitted from the array is substantially equal in the vertical and horizontal directions.

Further, the aspect ratio of the arrangement pitch of the light emitting diodes is made substantially equal, and the arrangement direction of the polarization conversion elements is arranged so as to form an angle of about 45 ° with the direction of the arrangement of the light emitting diodes. The apparatus provides a preferable novel realizing means having a configuration in which the pitch between the light beams emitted from the polarization conversion element array is substantially equal in the vertical and horizontal directions.

Further, an image projection apparatus in which the polarization conversion element array is an arrangement of a polarization beam splitter, a light beam reflection element, and a unit element having a half-wave plate, is a preferred specific configuration example of the polarization conversion element. Is provided.

Further, a light source in which light-emitting diodes having the same color are arranged is used as one light source array, light from the light source arrays of different light colors is combined to illuminate the liquid crystal light valve, and a plurality of light sources are provided. An image projection apparatus that performs multi-color display by sequentially switching the light emission of the array and operating the liquid crystal light valve in synchronization with the light emission of the array allows the optical system to be configured to be extremely small. An apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of an embodiment of an image projection apparatus according to the present invention.

FIG. 2 is a schematic diagram showing a first configuration example of a lighting unit of the image projection device according to the present invention.

FIG. 3 is a schematic diagram illustrating a second configuration example of the illumination unit of the image projection device according to the present invention.

FIG. 4 is a schematic diagram showing a configuration example using a transmission type liquid crystal light valve and a polarizing plate in the configuration of FIG. 1;

FIG. 5 is a schematic diagram showing a configuration example in which the uniformity of illuminance is improved in the image projection apparatus according to the present invention.

FIG. 6 is a schematic diagram showing another configuration example in which the uniformity of the illuminance is improved in the image projection apparatus according to the present invention.

FIG. 7 is a view for explaining a preferred arrangement of a retardation plate in the configuration as shown in FIG. 6;

FIG. 8 is a diagram for describing a preferred example of performing high-definition color display in the configuration of FIG. 1;

FIG. 9 is a schematic diagram showing a typical structure example of a conventional polarization conversion element.

FIG. 10 is a schematic diagram illustrating a configuration example of another conventional polarization conversion element.

FIG. 11 is a diagram showing an example in which an integrator optical system and a polarization conversion element are combined.

[Explanation of symbols]

10a: light emitting diode, 10b: emission position, 11-1
5: light emitting diode, 20, 30, lens, 40: polarization conversion element, 41: polarization beam splitter, 42: optical path changing element, 43: 1/2 wavelength plate (phase difference plate), 50: micro lens array, 101 ... Blue LED light source, 102
... green LED light source, 103 ... red LED light source, 111-
113: polarization conversion element, 121: dichroic prism, 131: polarization beam splitter, 141: reflection type liquid crystal light valve, 142, 143: polarization plate, 151
... Projection lens, 161 ... Screen, 171, 172
173: micro lens array, 181, 182, 18
3 micro lens array, 191 lens, 192
193: micro lens, 201: multi light source, 240
.., Polarization conversion element array, 241, polarization beam splitter, 242, optical path changing means, 243, phase difference plate, 29
2,293 ... Fly eye integrator optical system.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 5/30 G02B 5/30 19/00 19/00 G02F 1/13 505 G02F 1/13 505 1/1335 1/1335 1/13357 G03B 21/00 E G03B 21/00 33/12 33/12 G02F 1/1335 530 (72) Inventor Takanobu Osaka 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company, Ltd. 72) Inventor Ikuo Kato 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Kazuya Miyagaki 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Company (reference 2H042 CA06 CA10 CA14 CA17 2H049 BA05 BA06 BA42 BA43 BB03 BB63 BC22 2H052 BA01 BA02 BA09 BA14 2H088 EA13 HA13 HA17 HA20 HA21 HA23 HA24 HA25 HA28 2H091 FA05X FA05Z FA08X FA10X FA10Z FA11X FA11Z FA14Z X FA29X FA29Z FA45X FA45Z FD24 GA02 LA11 LA15 LA17

Claims (11)

[Claims] A light source comprising a plurality of light emitting diodes;
A liquid crystal light valve that is illuminated by the light source light from the light source and modulates a polarization state of the incident illumination light, and an image projection apparatus that includes a projection lens for projecting light emitted from the liquid crystal light valve, An image projection apparatus, comprising: a polarization conversion element array for individually converting polarization of light emitted from each of the light emitting diodes. 2. A lens is provided in an optical path of light emitted from each of the light emitting diodes so that light emitted from each of the light emitting diodes converges, and the polarization conversion element array is arranged near a convergence point at which the light is converged. 2. The image projection device according to claim 1, wherein the image projection device is provided corresponding to the arrangement of the light emitting diodes. 3. The polarization conversion element array according to claim 1, wherein the polarization conversion element array is arranged in an optical path near the light emitting diodes and in which beams emitted from the light emitting diodes do not substantially intersect. The image projection device according to any one of the preceding claims. 4. A lens for converging light emitted from a light emitting diode, and a polarization conversion element array is disposed in the vicinity of the light emitting diode and in an optical path in which beams emitted from each light emitting diode do not substantially intersect. The image projection device according to claim 2, wherein: 5. In a divergent light path near the polarization conversion element,
The image projection device according to claim 1, further comprising a lens array that converts light beams into substantially parallel light beams. 6. A plurality of light emitting diodes are arranged two-dimensionally, and a pitch between a plurality of light beams emitted from the polarization conversion element array is substantially equal in a vertical direction and a horizontal direction. 6. The image projection device according to any one of 1 to 5. 7. The light emitting diode according to claim 6, wherein the aspect ratio of the arrangement pitch of the light emitting diodes is about 2, and the arrangement direction of the polarization conversion elements is adjusted to the long direction of the arrangement pitch of the light emitting diodes. The image projection device according to any one of the preceding claims. 8. An arrangement in which the aspect ratio of the arrangement pitch of the light emitting diodes is substantially equal, and the arrangement direction of the polarization conversion elements is arranged so as to form an angle of approximately 45 ° with the direction of the arrangement of the light emitting diodes. The image projection device according to claim 6. 9. The polarization conversion element array according to claim 1, wherein the polarization conversion element array includes a polarization beam splitter, a light beam reflection element, and a unit element including a half-wave plate. 2. The image projection device according to 1. 10. The liquid crystal light valve according to claim 1, wherein a light source comprising light emitting diodes having the same light emitting color is arranged as one light source array, and light from the light source array of different light emitting colors is combined to illuminate the liquid crystal light valve. The image projection device according to claim 1, wherein: 11. The multicolor display according to claim 10, wherein the liquid crystal light valve is operated in synchronization with the switching while sequentially switching the light emission of the light source array of a plurality of colors. Image projection device.