JP2007041212A - Illuminating device and image projection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminating device capable of forming a color image by a single optical spacial modulation element without using a mechanically driven motor, and to provide an image projection apparatus using the illuminating device. <P>SOLUTION: The illuminating device includes: a plurality of light sources; a condensing optical system by which light emitted from the plurality of light sources is condensed into the same optical path; and the single optical spacial modulation element. The illuminating device synchronizes the plurality of light sources and the single optical spacial modulation element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illumination device and an image projection device using the same, and more particularly to an illumination device using a plurality of light sources and an optical spatial modulation element and an image projection device using the illumination device.

Conventionally, an image projector (optical projector) using a spatial light modulator such as a liquid crystal panel or a DMD (Digital Micro mirror Device) element has been proposed. For example, three liquid crystal panels as shown in FIG. There is known a three-plate image projection apparatus 100 using the above.
In FIG. 3, the illumination light emitted from the discharge lamp 101 is made substantially parallel light by the reflector 102 and then uniformly irradiated to the liquid crystal display elements 117 to 119 by the illumination optical system composed of the optical components 103 to 116. The At the same time, the three primary colors are separated from the illumination light by the dichroic mirrors 107 and 108 arranged in the illumination optical system, and the liquid crystal display elements 117 to 119 corresponding to the respective colors are irradiated. The light spatially modulated for each color by the liquid crystal display elements 117 to 119 is synthesized again by the cross prism 120 and projected onto the screen 122 by the projection lens 121.
In such a three-plate image projection apparatus 100, the illumination light is separated into three primary colors by the illumination optical system and applied to each liquid crystal display element. Therefore, the illumination light itself does not need to be modulated. Therefore, three liquid crystal display elements are required, and the light modulated for each color must be synthesized again. Therefore, the cross prism 120 is necessary. There is a problem of becoming.

Therefore, for example, as shown in FIG. 4, a single-plate image projection device 130 using a color wheel 134 and a DMD element 136 has been proposed (see Patent Document 1).
In FIG. 4, the illumination light emitted from the discharge lamp 131 is substantially collimated by the reflector 132 and then uniformly irradiated to the DMD element 136 by the illumination optical system configured by the optical components 133 to 135. The light spatially modulated by the DMD element 136 is projected onto the screen 138 by the projection lens 137. In the case of the single-plate image projection apparatus as described above, the original video signal input to the DMD element 136, which is a light spatial modulation element, is a signal corresponding to one frame of the image, further red, green, and blue. The signals are separated into three primary colors, and are configured in a time-sharing manner, for example, in the order of red, green, and blue.

The color wheel 134 arranged in the illumination optical system has a structure as shown in FIG. 5, for example. Of the incident illumination light, the R region is only red light and the G region is only green light. , B region has a spectral characteristic such that only blue light is transmitted.
Further, the color wheel 134 is provided with a motor (not shown), and for example, the R region, the G region, and the B region are sequentially rotated so as to pass through the illumination optical path. The rotation period is synchronized with the video signal time-divided for each color. For example, when a signal corresponding to a red portion of the video signal is input to the DMD element 136, the color wheel Since the R region of 134 passes through the illumination optical path, only the red light is applied to the DMD element 134.
Next, for example, when a signal corresponding to a green portion is input, since the G region passes through the illumination optical path, only green light is irradiated. Similarly, only blue light is emitted for the blue signal. In this way, it is known that a color image can be created with a single spatial light modulator if the video signal and the rotation of the color wheel 134 are synchronized.

JP 2001-92003 A

  However, in the single-plate image projector 130 using the color wheel 134 and the DMD element 136 shown in FIG. 4, the color wheel 134 is rotated by a mechanical drive using a motor. The life of the motor is greatly related, and when the life of the motor is exhausted, there arises a problem that the life of the image projection apparatus is also exhausted.

  In addition, when trying to improve the performance of the image projection device, it is necessary to increase the rotation speed of the motor, and as the rotation speed of the motor driven by mechanical drive increases, the rotation sound of the motor becomes a problem as noise. There is also.

  In consideration of the above-described points, the present invention provides an illuminating device that can create a color image by using a single light spatial modulation element without using a mechanically driven motor, and an image projection device using the same. Is.

  An illumination device according to the present invention includes a plurality of light sources, a condensing optical system that condenses light emitted from the plurality of light sources in the same optical path, and a single light spatial modulation element, It is set as the structure which synchronizes between a light source and the said single light spatial modulation element.

Preferably, at least one of the plurality of light sources of the illumination device according to the present invention is a semiconductor laser.
More preferably, the single light spatial modulation element of the illumination device according to the present invention is a liquid crystal display element.

  In the illumination device of the present invention, a color image can be created with a single light spatial modulation element without using a mechanically driven motor.

  An image projection apparatus according to the present invention includes a plurality of light sources, a condensing optical system that condenses light emitted from the plurality of light sources on the same optical path, a single light spatial modulation element, and the single light A projection optical system that projects an image modulated by the light spatial modulation element, and is configured to synchronize between the plurality of light sources and the single light spatial modulation element.

  In the image projection apparatus of the present invention, a color image can be created with one light spatial modulation element without using a mechanical drive motor.

  According to the lighting device of the present invention, since a color image can be created without using a mechanically driven motor, the lifetime of the lighting device can be extended.

  According to the image projection apparatus of the present invention, since a color image can be created without using a mechanically driven motor, the life of the image projection apparatus can be extended.

  Hereinafter, examples of the best mode for carrying out the image projection apparatus according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the following examples. The illumination device according to the present invention will be described together with an image projection device.

FIG. 1 is a schematic configuration diagram of an image projection apparatus 1 according to an embodiment of the present invention.
As shown in FIG. 1, the light source 2 of the image projection apparatus 1 according to this example includes a red laser diode 41 that emits red light that can be modulated, a green laser diode 42 that emits green light, and a blue light that emits blue light. It is composed of a plurality of light sources composed of a laser diode 43. For these laser diodes, semiconductor lasers manufactured using compounds such as gallium, arsenic, indyllium, and phosphorus are used. The light source is not limited to a laser diode, and an LED (light emitting diode) may be used as long as modulation is possible.

  In this example, the plurality of light sources constituting the light source 2 are all configured by semiconductor lasers. However, all the light sources are not limited to semiconductor lasers. For example, semiconductor lasers are used for red and blue light sources. The green light source may be configured using a solid-state laser. Further, a semiconductor laser may be used for the red light source, and an LED may be used for the blue and green light sources.

  In the image projection apparatus 1 of this example, a cross prism 44 that condenses each light in the same optical path is disposed at a position facing the light emission side of each laser diode 41 to 43. On the optical axis on the light emission side of the cross prism 44, first and second fly-eye lenses 45 and 46 for uniforming the spatial distribution of the light beam and a condenser lens 47 are arranged in this order. The added condensing optical system is configured. The illumination device 10 is configured by the illumination optical system including the first fly-eye lens 45, the second fly-eye lens 46, and the condenser lens 47 and the light source 2.

  On the optical axis on the light emission side of the condenser lens 47, a single transmissive liquid crystal display device 48, which is an optical spatial modulation element, is disposed so as to face the condenser lens 47. The transmissive liquid crystal display device 48 is formed in a so-called single plate shape. In this example, the transmissive liquid crystal display element 48 is used as the light spatial modulation element, but the light spatial modulation element is not limited to this, and for example, a reflective liquid crystal display element or a DMD element may be used. The liquid crystal display device is prepared by, for example, providing a striped ITO electrode on a transparent glass substrate and enclosing the liquid crystal. A voltage is applied to the ITO electrode of the liquid crystal display device in advance and irradiated. The liquid crystal display device is operated so as to change the polarization state of the light to be read by changing the voltage applied to the liquid crystal according to the intensity of the light to be read.

  A projection lens 49 for projecting the light modulated by the transmissive liquid crystal display device 48 onto the screen is disposed on the optical axis of the light transmission side of the transmissive liquid crystal display device 48. Is provided with a screen 50. The illumination device 10 and the projection lens 49 constitute the image projection device 1.

  The video circuit unit 51 connected to the light source 2 or the like is a video signal for generating a synchronization signal for synchronizing the input unit 21 to which an input video is input, the laser diodes 41 to 43 of each color, and the transmissive liquid crystal display device 48. The processing unit 22, the signal adjustment unit 23 that generates a modulation signal for adjusting image information, and the modulation signal generated by the signal adjustment unit 23 are separated for laser driving and liquid crystal display device driving. A signal separating unit 23, a control unit 25 that synchronizes the driving of the laser diode and the driving of the liquid crystal display device by a synchronizing signal, the liquid crystal driving unit 26 that drives the transmissive liquid crystal display device 48, and the red laser 41. A red laser driving unit 31 for driving, a green laser driving unit 32 for driving the green laser 42, and a blue laser driving unit 33 for driving the blue laser 43 are configured.

  The red laser diode 41, the green laser diode 42, the blue laser diode 43, and the transmissive liquid crystal display device 48, which is a light spatial modulation element, constituting the light source 2 of the illumination device 10 are connected to a part of the video circuit unit 51. Yes.

  Specifically, the red laser diode 41 of the video circuit unit 51 is connected to the red laser diode 41 of the light source, and the green laser drive unit 32 of the video circuit unit 51 is connected to the green laser diode 42 of the light source. The blue laser diode 43 of the video circuit 51 is connected to the blue laser diode 43 of the light source. The transmissive liquid crystal display device 48 is connected to the liquid crystal driving unit 26 of the video circuit unit 51. Further, the color laser driving units 31 to 33 and the liquid crystal driving unit 26 of the video circuit unit 51 are connected to each other via the control unit 25. The video circuit 51 is connected to a power source 52 that supplies power for driving each drive unit.

  In the video circuit unit 51, when video displayed on a screen or the like is input to the input unit 21, this video signal is sent from the input unit 21 to the video signal processing unit 22. Next, in the video signal processing unit 22, a control synchronization signal is generated based on the video signal sent from the input unit 21, and this synchronization signal is sent to the control unit 25. Next, the signal adjustment unit 23 generates a modulation video signal and a laser modulation signal for the liquid crystal display element for adjusting the image information based on the video signal sent from the video signal processing unit 22. Are sent to the signal separator 24. Next, in the signal separation unit 24, the signal sent from the signal adjustment unit 23 is used to drive the red laser modulation signal for driving the red laser 41, the green laser modulation signal for driving the green laser 42, and the blue laser 43. The blue laser modulation signal to be transmitted and the liquid crystal display element modulation signal for driving the transmissive liquid crystal display device 48 are separated, and the laser modulation signals of the respective colors are supplied to the laser driving units 31 to 33 corresponding to the respective colors. Is sent to the liquid crystal drive unit 26.

  Further, when a synchronizing signal is sent from the control unit 25 of the video circuit unit 51 to the liquid crystal driving unit 26 and the laser driving units 31 to 33 for the respective colors, the transmissive liquid crystal display device 48 is driven by the liquid crystal driving unit 26 and the lasers for the respective colors. The laser diodes 41 to 43 of each color are driven at a predetermined timing by the driving units 31 to 33.

  Specifically, when a liquid crystal display element modulation signal is sent from the liquid crystal driving unit 26 to the transmissive liquid crystal display device 48, the transmissive liquid crystal display device 48 is driven according to the waveform of the modulation signal. When a red laser modulation signal is sent from the red laser driving unit 31 to the red laser diode 41, the red laser diode 41 is driven according to the waveform of this signal. When the green laser modulation signal is sent from the green laser driving unit 32 to the green laser 42, the green laser 42 is driven according to the waveform of this signal. When a blue laser modulation signal is sent from the blue laser driving unit 33 to the blue laser diode 43, the blue laser diode 43 is driven according to the waveform of this signal. That is, the transmissive liquid crystal display device 48 and the laser diode 41 shell 3 of each color are driven by the liquid crystal display element modulation signal output from the liquid crystal driving unit 26 and the laser modulation signal of each color, and the transmissive liquid crystal display element 48 is driven. A spatial light modulation is performed in FIG.

  FIG. 2 shows the relationship between the waveform of each color laser modulation signal output from the laser driving unit and the waveform of the liquid crystal display element modulation signal output from the liquid crystal driving unit.

  As shown in FIG. 2, the liquid crystal drive unit 26 outputs a liquid crystal display element modulation video signal 61 having a waveform as shown in the figure. Further, the red color laser modulation signal 62, the green color laser modulation signal 63, and the blue color laser modulation signal 64 having waveforms as shown in the figure are output from the laser driving units 31 to 33 for the respective colors. Further, as shown in the figure, the red laser modulation signal 62, the green laser modulation signal 63, and the blue laser modulation signal 64 are composed of waveforms set so that their output regions do not overlap each other.

  The liquid crystal display element modulating video signal 61 is configured to time-divide portions corresponding to red, green, and blue of the original video signal for one frame. That is, the liquid crystal display element modulating video signal 61 includes a portion 61-a corresponding to a red video signal for one frame, a portion 61-b corresponding to a green video signal, and a portion 61- corresponding to a blue video signal. Time division is performed in the order of c. In this example, the liquid crystal display element modulating video signal 61 is configured to be continuous in the order of red, green, and blue. However, the order of the colors of the time-division video signals is not limited to this. For example, the order may be green, red, and blue.

  Further, as shown in FIG. 2, the liquid crystal display element modulation video signal 61 and the red laser modulation signal 62, the green laser modulation signal 63, and the blue laser modulation signal 64 are set to be synchronized with each other. Has been. That is, when the portion 61-a corresponding to red is output from the liquid crystal display element modulation video signal 61, the red laser modulation signal 62 is output from the red laser driving unit 31 and the red laser diode 62 is turned on. Is set to Further, while the red laser diode is lit, the green laser diode 63 and the blue laser diode 64 other than red are set to be turned off.

  When the portion 61-b corresponding to green is output from the liquid crystal display element modulation video signal 61, the green laser modulation signal 63 is output from the green laser driving unit 32, and the green laser diode 42 is turned on. It is set to be. In this case, the red laser diode 62 and the blue laser diode 64 other than green are set to be turned off. Furthermore, when the portion 61-c corresponding to blue is output in the liquid crystal display element modulation video signal 61, the blue laser modulation signal 64 from the blue laser driving unit 33 is in an output state, and the blue laser diode is output. 64 is set to be turned on, and the red laser diode 62 and the green laser diode 63 other than blue are set to be turned off.

  The illumination lights of the respective colors emitted from the laser diodes 41 to 43 of the respective colors enter the cross prism 44, then are refracted in the cross prism 44, pass through the same optical path, and are transmissive liquid crystal that is a light spatial modulation element. The light enters the display element 48. As described above, the light incident on the transmissive liquid crystal display element 48 is synchronized for each color, and red, green, and blue images are sequentially and spatially modulated in a time division manner. The light spatially modulated by the transmissive liquid crystal display element 48 is incident on the projection lens 49. In the transmissive liquid crystal display device 48, the display image is switched instantaneously for each color, so that the display projected on the screen 50 through the projection lens 49 is an image of each color at very short intervals on the screen. Are displayed in sequence. For this reason, since the image on the screen appears as an afterimage to the eyes, a full-color image is recognized.

  According to the lighting device of this example, a plurality of light sources are electrically modulated and driven without using a color wheel that is operated by a mechanical drive using a motor or the like, and synchronized with a single light spatial modulation element. Since the color sequential is realized by this, the life of the lighting device can be extended as compared with the conventional color wheel rotating type. In addition, since the electric modulation drive is used without using the mechanically driven motor that generates the rotation sound, the noise generated by the rotation sound of the motor can be reduced.

  In addition, according to the illumination device of this example, the light source is configured for each of the three primary colors, and a single light spatial modulation element is used, so there is no need for a device for separating the light source into three colors. Since it is not necessary to use a color hole, the illumination optical system can have a simple configuration. Therefore, according to the illumination device of this example, the entire illumination device can be made inexpensive and small. In addition, according to the illumination device of this example, since the light spatial modulation element is constituted by one piece as compared with the conventional three-plate image projection device, the number of parts can be reduced, and the illumination device can be made inexpensive and small. can do.

  According to the image projection apparatus of this example, the life of the entire image projection apparatus can be extended by using an illumination device that can extend the life. Further, according to the image projecting apparatus of this example, the entire image projecting apparatus can be made inexpensive and compact by using an illumination device that can be made inexpensive and compact.

FIG. 1 is a schematic configuration diagram of an image projection apparatus according to the present invention. FIG. 2 shows the relationship between the waveform of the laser modulation signal of each color and the waveform of the liquid crystal display element modulation signal. FIG. 3 is a schematic configuration diagram of a conventional three-plate image projector. FIG. 4 is a schematic configuration diagram of a conventional single-plate image projection apparatus. FIG. 5 is an enlarged view of a color wheel used in a conventional single-plate image projector.

Explanation of symbols

1 .... Image projection device 2 .... Light source 10 .... Illumination device 41 ... Red laser 42 ... Green laser 43 ... Blue laser 44 ... Cross prism 45 ... First fly eye lens 46 .. Second fly-eye lens 47.. Condensing lens 48.. Transmission type liquid crystal display device 49.. Projection lens 50.. Screen 51.

Claims (6)

Multiple light sources;
A condensing optical system for condensing the light emitted from the plurality of light sources in the same optical path;
A lighting device comprising a single spatial light modulator,
A lighting device, wherein the plurality of light sources and the single spatial light modulator are synchronized. The lighting device according to claim 1, wherein at least one of the plurality of light sources is a semiconductor laser. The lighting device according to claim 1, wherein the single light spatial modulation element is a liquid crystal display element. Multiple light sources;
A condensing optical system for condensing the light emitted from the plurality of light sources in the same optical path;
A single spatial light modulator;
A projection optical system that projects an image modulated by the single light spatial modulation element,
An image projection apparatus, wherein the plurality of light sources and the single light spatial modulation element are synchronized. The image projection apparatus according to claim 4, wherein at least one of the plurality of light sources is a semiconductor laser. The image projection apparatus according to claim 4, wherein the single light spatial modulation element is a liquid crystal display element.

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