JP2010271443A - Projector and picture-displaying method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector which displays a resolution-heightened picture, without increasing the scanning speed of laser light by an optical scanner, and to provide a picture-display method. <P>SOLUTION: Laser light 2 is emitted from a laser light source 1 toward a two-dimensional MEMS (microelectromechanical systems) mirror 3. The two-dimensional MEMS mirror 3 makes the laser light 2 two-dimensionally scan toward a transmission-type liquid crystal panel 5. In each pixel of the transmission-type liquid crystal panel 5, the intensity of the laser light 2 is modulated, and the laser light 2 is projected to a screen 10 to display a picture 9; the resolution of the displayed picture 9 is determined by the number of the pixels of the transmission-type liquid crystal panel 5; when the laser light 2 scans the pixel of the transmission-type liquid crystal panel 5 as a whole by the MEMS mirror 3, within a period of time in which a single frame of the picture 9 is displayed, the high-resolution picture 9 is displayed, irrespective of the scanning speed by the two-dimensional MEMS mirror 3. Accordingly, the high-resolution picture 9 is displayed without increasing the scanning speed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a projector and an image display method for projecting and displaying an image on a screen or the like.

  Conventionally, a projector has been used as a device for displaying a large screen image. In such a projector, the intensity of light from a light source is modulated by a liquid crystal display (LCD) or the like, and an image is displayed by projecting the light onto a large screen or the like.

  A projector using a laser light source as a light source has been developed (see, for example, paragraph [0073] of FIG. 6 and FIG. 6). In the projector described in Patent Document 1, a laser beam emitted from a laser light source is scanned on a screen by a scanning unit such as a MEMS (Micro Electro Mechanical Systems) mirror to display an image. When the laser light is emitted, the output level of the laser light source is modulated in accordance with the luminance level of the video signal, thereby expressing the gradation of the displayed video.

JP 2008-288616 A

  However, in the projector described in Patent Document 1, in order to display a high-resolution image with a large number of pixels on the projection screen, the scanning speed of the laser beam by the scanning unit must be high. If the scanning speed of the laser beam is high and the number of scans of the laser beam within the time for displaying one frame of the image is not large, a high-resolution image having a large number of pixels is not displayed.

  In order to increase the scanning speed of the laser beam, the scanning unit that scans the laser beam must operate at a high speed. However, the scanning unit may be destroyed by operating at a high speed. In particular, when the scanning unit is formed in a small size for the purpose of downsizing the projector, the possibility that the scanning unit operating at high speed is destroyed increases.

  In view of the circumstances as described above, an object of the present invention is to provide a projector and an image display method capable of displaying a high-resolution image without increasing the scanning speed of the laser beam by the optical scanner. .

In order to achieve the above object, a projector according to an embodiment of the present invention includes a laser light source, an optical modulator, and an optical scanner.
The laser light source emits laser light.
The optical modulator modulates the intensity of the laser beam to display an image.
The optical scanner scans the emitted laser light two-dimensionally toward the optical modulator.

  According to this projector, the resolution of the displayed image is determined by the optical modulator, and the optical scanner scans the laser beam toward the optical modulator. Accordingly, if laser light is scanned over the entire optical modulator by the optical scanner within the time for displaying one frame of the video, a high-resolution video is displayed regardless of the scanning speed of the optical scanner. Thereby, it is possible to display a high-resolution image without increasing the scanning speed of the laser beam by the optical scanner.

  The optical modulator may include a plurality of pixels that individually modulate the intensity of the laser light. In this case, the beam diameter of the scanned laser beam may be larger than the area of each pixel.

  In order for an image to be displayed, laser light must be scanned across the pixels of the optical modulator within the time that one frame of the image is displayed. In the projector of this embodiment, the beam diameter of the laser beam is larger than the area of each pixel, so that light is scanned over the entire pixel with a small number of scans. Thereby, a high-resolution video can be displayed without increasing the scanning speed.

The projector may further include a lens system.
The lens system is disposed between the laser light source and the optical scanner, and makes the beam diameter of the emitted laser light larger than the area of each pixel.

  In this projector, the beam diameter of the laser light emitted from the laser light source is made larger than the area of each pixel by a lens system disposed between the laser light source and the optical scanner, and the laser light is transmitted by the optical scanner. Scanned to a light modulator.

The laser light source may emit the laser light having a first polarization plane. In this case, the light modulator includes a transmissive liquid crystal panel and a polarizing plate.
The transmissive liquid crystal panel can transmit the laser light while rotating the first polarization plane.
The polarizing plate transmits the laser light having a second polarization plane different from the first polarization plane out of the laser light transmitted through the transmissive liquid crystal panel.

  In this projector, a transmissive liquid crystal panel and a polarizing plate are used as an optical modulator. Since the laser light having the first polarization plane is emitted from the laser light source, there is no need to dispose a polarizing plate between the laser light source and the transmissive liquid crystal panel. That is, in the projector of this embodiment, if one polarizing plate is disposed behind the liquid crystal panel, an image is displayed, which is advantageous for downsizing the projector and simplifies the structure of the projector.

When the laser light source emits the laser light having the first polarization plane, the light modulator may include a reflective liquid crystal panel and a polarization separator.
The reflective liquid crystal panel can reflect the laser light while rotating the first polarization plane.
The polarization separator has the second polarization plane different from the first polarization plane among the laser beams incident on the reflection-type liquid crystal panel and reflected by the reflection-type liquid crystal panel. A laser beam is projected.

  In this projector, a reflective liquid crystal panel and a polarization separator are used as an optical modulator. The polarization separator reflects the laser light having the first polarization plane and transmits the laser light having the second polarization plane. Alternatively, the laser beam having the first polarization plane is transmitted and the laser beam having the second polarization plane is reflected. In any case, the laser light is incident on the reflective liquid crystal panel by the polarization separator, and the laser light is reflected by the reflective liquid crystal panel so as to return to the polarization separator again. Then, the laser beam is projected by being reflected or transmitted by the polarization separator.

The light modulator may have a plurality of micromirrors.
The plurality of micromirrors reflect the laser light, and the angle at which the laser light is reflected is controlled to individually modulate the intensity of the laser light.

  The laser light source may emit the red, green, and blue laser lights in a time-sharing manner. In this case, the optical modulator modulates each intensity of the red, green, and blue laser beams. Thereby, in the projector of this embodiment, a full-color image is displayed.

An image display method according to an aspect of the present invention includes emitting laser light toward an optical scanner.
The laser beam is scanned two-dimensionally toward the optical modulator by the optical scanner.
An image is displayed by modulating the intensity of the laser beam scanned on the optical modulator by the optical modulator.

  As described above, according to the present invention, a high-resolution image can be displayed without increasing the scanning speed of the laser beam by the optical scanner.

1 is a perspective view schematically showing a configuration of a projector according to a first embodiment. It is a top view of the projector shown in FIG. It is a top view which shows the laser beam scanned on the transmissive liquid crystal panel by the two-dimensional MEMS mirror. It is a top view which shows the laser beam scanned on the transmissive liquid crystal panel by the two-dimensional MEMS mirror. It is a top view which shows schematically the projector which concerns on 2nd Embodiment. It is a top view which shows roughly the projector which concerns on 3rd Embodiment. It is a top view which shows roughly the projector which concerns on 4th Embodiment. It is a top view which shows roughly the projector which concerns on 5th Embodiment. It is a top view which shows roughly the projector which concerns on 6th Embodiment. It is a figure for demonstrating the timing when the video signal of each color and the emitted signal of each color are output by a control part. It is a figure which shows the frame of 3 colors projected on a screen corresponding to the timing shown in FIG. It is a figure which shows the modification of the projector which concerns on 1st Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
[Projector configuration]
FIG. 1 is a perspective view schematically showing a configuration of a projector according to the first embodiment of the present invention. FIG. 2 is a plan view of projector 100 shown in FIG. The projector 100 includes a laser light source 1 that emits laser light 2, a two-dimensional MEMS mirror 3 that scans the emitted laser light 2 two-dimensionally, and an optical modulator 4 that modulates the intensity of the laser light 2. .

  As the laser light source 1, for example, a semiconductor laser, a gas laser, a solid laser, or the like is used. Alternatively, these may be used in combination with a crystal or the like that converts the wavelength. Alternatively, a laser light source 1 that combines a plurality of laser beams having different wavelengths with a dichroic mirror, a prism, or the like and emits the combined laser beam as a laser beam 2 may be used.

  In the present embodiment, the laser light 2 emitted from the laser light source 1 is linearly polarized light, and its polarization plane is determined in one direction. For example, a laser beam 2 having a polarization plane defined in one direction is provided in the path of the laser beam 2 in the laser light source 1 by providing a polarization element that transmits or reflects only the laser beam having a specific polarization plane. Is emitted from the laser light source 1.

  The two-dimensional MEMS mirror 3 has a tilt angle controlled by electrostatic force, magnetic force, piezoelectric effect, or the like. Thereby, the reflection angle of the laser beam 2 is controlled, and the laser beam 2 is scanned two-dimensionally. In the present embodiment, ESS212 manufactured by Nippon Signal is used.

  Instead of the two-dimensional MEMS mirror 3, two or more one-dimensional MEMS mirrors may be used, and the laser beam 2 may be scanned two-dimensionally. Alternatively, two or more galvanometer mirrors or polygon mirrors may be used, or a combination thereof may be used to scan the laser beam 2 two-dimensionally.

  The light modulator 4 includes a transmissive liquid crystal panel 5 and a polarizing plate 6. The transmissive liquid crystal panel 5 has liquid crystal molecules sandwiched between a pair of transparent electrodes, and the polarization plane of light transmitted through the transmissive liquid crystal panel 5 can be rotated. Examples of the driving method of the transmissive liquid crystal panel 5 include a VA (Vertical Alignment) type, an IPS (In-Plane Switching) type, and a TN (Twisted Nematic) type.

  The transmissive liquid crystal panel 5 has a plurality of pixels (not shown), and individually rotates a polarization plane of light transmitted through each pixel for each pixel. The number of pixels is, for example, the resolution of the image 9 displayed on the screen 10 shown in FIG. 1. In this embodiment, 1920 pixels are provided in the horizontal direction and 1080 pixels in the vertical direction in the transmissive liquid crystal panel 5. It has been. In the present embodiment, laser light 2 having a beam diameter larger than the area of each pixel is emitted from the laser light source 1.

  The polarizing plate 6 transmits only light having a polarization plane in one direction out of the light transmitted through the transmissive liquid crystal panel 5. The polarizing plate 6 is not limited to a plate shape, and for example, a film shape may be used. In the present embodiment, a polarizing plate 6 that transmits only light having a polarization plane of the laser light 2 emitted from the laser light source 1 and a polarization plane that is substantially orthogonal is used.

  As shown in FIG. 2, the projector 100 includes a control unit 7 that comprehensively controls driving of the laser light source 1, the two-dimensional MEMS mirror 3, and the transmissive liquid crystal panel 5. For example, the control unit 7 includes a laser driver that drives the laser light source 1, a driver that drives the two-dimensional MEMS mirror 3, a liquid crystal driver that drives the transmissive liquid crystal panel 5, and the like.

  For example, the control unit 7 may be realized by hardware, or may be realized by both software and hardware. Typically, the hardware is a CPU (Central Processing Unit), MPU (Micro Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array). ), Application Specific Integrated Circuit (ASIC), Network Interface Card (NIC), Wireless NIC (WNIC), and the like. Various programs constituting the software are stored in a ROM or other storage device.

[Projector operation]
When the video signal 50 is input to the control unit 7, the liquid crystal driver applies a voltage to each pixel of the transmissive liquid crystal panel 5 based on the video signal 50, so that the transmissive liquid crystal panel 5 generates an image. Further, the control unit 7 outputs an emission signal 55 to the laser light source 1 and outputs a scanning signal 60 to the two-dimensional MEMS mirror 3. Upon receiving the emission signal 55, the laser light source 1 emits laser light 2 having a certain intensity toward the two-dimensional MEMS mirror 3. The two-dimensional MEMS mirror 3 scans the laser beam 2 in a two-dimensional manner toward the transmissive liquid crystal panel 5 in accordance with the scanning signal 60.

  3 and 4 are plan views showing the laser beam 2 scanned on the transmissive liquid crystal panel 5 by the two-dimensional MEMS mirror 3. 3 and 4, the plurality of pixels of the transmissive liquid crystal panel 5 are not shown.

  First, the laser beam 2 is scanned from the upper left position a of the transmissive liquid crystal panel 5 toward the upper right position b of the transmissive liquid crystal panel 5. Since the position b is located on the transmissive liquid crystal panel 5 below the position a, the laser light 2 is scanned obliquely from the position a to the position b.

  Next, the laser beam 2 is scanned obliquely from the position b toward the position c below the position a. The laser beam 2 is scanned from the position c to the position d below the position b, from the position d to the position e below the position c, and thereafter similarly following the alphabet shown in FIG. . In FIG. 3, the locus of the center of the scanned laser beam 2 is indicated by a broken line.

  An area where the laser beam 2 is not irradiated between the locus formed by the spot of the laser beam 2 scanned from the position a to the position b and the locus formed by the spot of the laser beam 2 scanned from the position c to the position d. The laser beam 2 is scanned so that there is no gap. Similarly, the laser beam 2 is scanned at other positions, so that there is no region that is not irradiated with the laser beam 2 in the locus formed by the spot of the laser beam 2 scanned two-dimensionally.

  The region scanned from the position b to the position m includes an overlapping region where the laser beam 2 is scanned twice. A uniform illuminance distribution is obtained in this overlapping region where the laser beam 2 having a constant intensity is scanned twice. Therefore, if an effective pixel area Z (area surrounded by a broken line in FIG. 4) in which all the pixels of the transmissive liquid crystal panel 5 are arranged is installed in this area, an image 9 having a uniform illuminance distribution can be obtained. In the effective pixel region Z, the laser beam 2 is incident on each pixel.

  The voltage applied to each pixel by the liquid crystal driver is held by, for example, a capacitor provided for each pixel. Depending on the magnitude of this voltage, the polarization plane of the laser light 2 incident on each pixel changes the liquid crystal molecule. Is rotated by. The laser beam 2 whose polarization plane has been rotated next enters the polarizing plate 6, but the intensity of the laser beam 2 that passes through the polarizing plate 6 varies depending on the degree of rotation of the polarization plane. The laser beam 2 whose polarization plane is not rotated by the liquid crystal molecules is blocked by the polarizing plate 6. That is, according to the voltage applied to each pixel, the intensity of the laser beam 2 incident on the pixel is modulated, and the image 9 is displayed by projecting the laser beam 2.

  According to the projector 100, the resolution of the displayed image 9 is determined by the number of pixels of the transmissive liquid crystal panel 5, and the two-dimensional MEMS mirror 3 scans the laser light 2 toward the transmissive liquid crystal panel 5. . Accordingly, if the laser light 2 is scanned over the entire pixel of the transmissive liquid crystal panel 5 by the two-dimensional MEMS mirror 3 within the time (typically 1/60 second) in which one frame of the image 9 is displayed, Regardless of the scanning speed of the two-dimensional MEMS mirror 3, a high-resolution image 9 is displayed.

  In the projector 100 of the present embodiment, since the beam diameter of the laser light 2 is larger than the area of each pixel, 1920 pixels in the horizontal direction and 1080 pixels in the vertical direction of the transmissive liquid crystal panel 5 are arranged at the position a. To the position n can be scanned with a small number of scans. As a result, the high-resolution video 9 can be displayed without increasing the scanning speed.

  As the beam diameter of the laser beam 2 is larger, the laser beam 2 is scanned over the entire pixels of the transmissive liquid crystal panel 5 with a smaller number of scans. Therefore, the scanning speed of the two-dimensional MEMS mirror 3 can be reduced. The beam diameter of the laser beam 2 is set as appropriate so that a desired scanning speed (number of scans) can be realized.

  In the projector 100 of the present embodiment, the laser light source 1 emits laser light 2 that is linearly polarized light, and the polarization plane of the laser light 2 is determined in one direction. Therefore, it is not necessary to dispose a polarizing plate between the laser light source 1 and the transmissive liquid crystal panel 5, and if one polarizing plate 6 is disposed on the side of the transmissive liquid crystal panel 5 on which the laser light 2 is emitted, an image 9 is obtained. Is displayed. Thereby, it is advantageous for miniaturization of the projector 100, and the structure of the projector 100 can be simplified.

  In FIGS. 1 and 2, trajectories created by the laser light 2 scanned by the two-dimensional MEMS mirror 3 are indicated by broken-line square pyramids X and triangles Y, respectively. Since the laser beam 2 has high directivity, the laser beam 2 is projected linearly from the apex V of the quadrangular pyramid X and the triangle Y located on the two-dimensional MEMS mirror 3, and an image 9 is displayed. As a result, even if an imaging device such as a projection lens is not used, the image 9 is displayed without blurring. Since the imaging device is not used, focus adjustment is not necessary, and a blurred image 9 is displayed no matter what distance the screen 10 is placed from the projector 100. Further, since no imaging device is used, it is advantageous for downsizing the projector 100 and the structure of the projector 100 can be simplified.

<Second Embodiment>
FIG. 5 is a plan view schematically showing a projector according to the second embodiment of the present invention. In the following description, the description of the same parts as those of the projector 100 described in the above embodiment will be omitted or simplified.

  In the projector 200 according to the present embodiment, the lens system 220 is disposed between the laser light source 1 and the two-dimensional MEMS mirror 3 in the projector 100 according to the first embodiment. The lens system 220 makes the beam diameter of the laser light 2 emitted from the laser light source 1 larger than the area of each pixel of the transmissive liquid crystal panel 5. The laser beam 2 having a beam diameter increased by the lens system 220 is scanned on the transmissive liquid crystal panel 5 by the two-dimensional MEMS mirror 3.

  The lens system 220 includes a concave lens 220a that diffuses the laser light 2 emitted from the laser light source 1, and a convex lens 220b that condenses the laser light 2 diffused by the concave lens 220a. However, the configuration is not limited to this, and a single concave lens or convex lens may be used as the lens system 220, or two or more lenses may be used in combination.

  The beam diameter of the laser light source 1 may be increased by appropriately setting the structure of the laser light source 1, but the laser light source 1 can be obtained by installing the lens outside the laser light source 1 as in the present embodiment. The structure can be simplified.

<Third Embodiment>
FIG. 6 is a plan view schematically showing a projector according to the third embodiment of the present invention. The projector 300 according to the present embodiment uses a reflective liquid crystal panel 305 and a polarization beam splitter 306 as the light modulator 304.

  The reflective liquid crystal panel 305 has liquid crystal molecules sandwiched between a reflective electrode and a transparent electrode, and reflects light incident from the transparent electrode side by the reflective electrode. When light is reflected, the plane of polarization of the light rotates according to the voltage applied to the reflective electrode and the transparent electrode. Examples of such a liquid crystal panel include an LCOS (Liquid crystal on silicon) type liquid crystal panel. Similar to the transmissive liquid crystal panel 5 described in the first embodiment, the reflective liquid crystal panel 305 has a plurality of pixels, and the number of pixels is the resolution of the displayed image.

  The polarization beam splitter 306 separates the light incident on the polarization beam splitter 306 by its polarization plane. The polarizing beam splitter 306 of the present embodiment is a prism type, and is configured by bonding two triangular prisms 306a made of, for example, glass. On the bonding surface 306b of the two prisms 306a, an optical thin film such as a dielectric multilayer film or a metal thin film is formed by a vacuum deposition method, a sputtering method, or the like. Transmits polarized light. A planar type may be used as the polarization beam splitter 306.

[Projector operation]
A voltage is applied to each pixel of the reflective liquid crystal panel 305 based on the video signal. At this time, the laser light source 301 emits laser light 302 that is S-polarized light toward the bonding surface 306 b of the polarization beam splitter 306 toward the two-dimensional MEMS mirror 303. The emitted laser beam 302 is scanned two-dimensionally by the two-dimensional MEMS mirror 303 toward the bonding surface 306 b of the polarization beam splitter 306. The incident angle of the scanned laser beam 302 with respect to the adhesive surface 306b is approximately 45 degrees.

  Since the laser beam 302 scanned on the bonding surface 306b of the polarization beam splitter 306 is S-polarized light, the traveling direction is bent by about 90 degrees and reflected by the bonding surface 306b. The reflected laser beam 302 enters each pixel of the reflective liquid crystal panel 305, and the plane of polarization is rotated by liquid crystal molecules to which a voltage is applied. The laser light 302 is reflected by the reflective electrode of the reflective liquid crystal panel 305 and is incident on the adhesive surface 306 b of the polarizing beam splitter 306 again.

  In each pixel of the reflective liquid crystal panel 305, the laser light 302 whose polarization plane has been rotated passes through the adhesive surface 306 b of the polarization beam splitter 306 and is projected onto the screen 10. At this time, the intensity of the laser light 302 transmitted through the bonding surface 306b varies depending on the degree of rotation of the polarization plane. Therefore, by controlling the voltage applied to each pixel, the intensity of the laser beam 302 incident on each pixel is modulated, and an image is displayed by projecting the laser beam 302.

  In the transmissive liquid crystal panel 5 described in the first embodiment, the area through which the laser light 2 can pass in each pixel is reduced by the wiring connected to the pair of transparent electrodes. That is, in the transmissive liquid crystal panel 5, the aperture ratio of each pixel is small. On the other hand, in the reflective liquid crystal panel 305 of the present embodiment, the wiring and the like connected to the reflective electrode and the transparent electrode are provided on the side of the reflective electrode opposite to the side where the liquid crystal molecules are provided. That is, the reflective liquid crystal panel 305 has a larger aperture ratio of each pixel than the transmissive liquid crystal panel 5. Therefore, the utilization efficiency of the laser beam 2 is increased, and an image with high luminance is displayed. Further, since the polarization disturbance in the liquid crystal molecules of each pixel is small, the contrast of the displayed image is increased.

<Fourth Embodiment>
FIG. 7 is a plan view schematically showing a projector according to the fourth embodiment of the present invention. The projector 400 according to the present embodiment uses a reflective liquid crystal panel 405 and a wire grid polarizer 406 as the light modulator 404. Similar to the polarization beam splitter 306 described in the third embodiment, the wire grid polarizer 406 separates light incident on the wire grid polarizer 406 by its polarization plane.

  The wire grid polarizer 406 has a fine groove structure in which a metal thin film such as aluminum or tungsten formed on a transparent substrate is periodically formed extending in one direction. The metal thin film is formed by, for example, a vacuum deposition method or a sputtering method. The minute groove for dividing the metal thin film is formed by, for example, combining an interference exposure method and an etching method. Instead of the interference exposure method, an electron beam drawing method, an X-ray lithography method, or the like may be combined with the etching method. The wire grid polarizer 406 of this embodiment transmits light that becomes P-polarized light and reflects light that becomes S-polarized light with respect to an incident surface 406b on which light is incident.

[Projector operation]
Laser light 402 that becomes P-polarized light is emitted from the laser light source 401 to the incident surface 406 b of the wire grid polarizer 406. The emitted laser light 402 is scanned two-dimensionally by the two-dimensional MEMS mirror 403 toward the incident surface 406 b of the wire grid polarizer 406.

  Since the laser beam 402 scanned on the incident surface 406b of the wire grid polarizer 406 is P-polarized light, it passes through the incident surface 406b and enters each pixel of the reflective liquid crystal panel 405. The incident laser beam 402 has its polarization plane rotated at each pixel and reflected toward the wire grid polarizer 406. Then, the light is reflected by the incident surface 406b of the wire grid polarizer 406 and projected onto a screen or the like. At this time, the intensity of the laser beam 402 reflected by the incident surface 406b varies depending on the degree of rotation of the polarization plane. An image is displayed by projecting the laser beam 402.

  The incident angle with respect to the incident surface 406b of the laser light 402 scanned on the incident surface 406b of the wire grid polarizer 406 by the two-dimensional MEMS mirror 403 varies depending on the scanned position. However, the wire grid polarizer 406 has a higher polarization separation function with respect to the incident angle of incident light than the polarizing beam splitter 306 described in the third embodiment. For example, the transmittance of the P-polarized light and the reflectance of the S-polarized light with respect to the laser light 402 having an incident angle different from 45 degrees than the transmittance of the P-polarized light and the reflectance of S-polarized light with respect to the laser light 402 having the incident angle of 45 degrees. Is unlikely to go down. Therefore, the projector 400 according to the present embodiment using the wire grid polarizing plate 406 displays an image having higher brightness and contrast than the projector 300 using the polarizing beam splitter 306.

<Fifth Embodiment>
FIG. 8 is a plan view schematically showing a projector according to the fifth embodiment of the invention. In the projector 500 according to the present embodiment, a light modulator 504 in which a plurality of minute mirrors are arranged two-dimensionally is used. The plurality of micromirrors are typically formed by MEMS technology, and the tilt angle is controlled by electrostatic force, magnetic force, piezoelectric effect, or the like. Examples of such a device include DMD (registered trademark) (Digital Micro-mirror Device) used for a projector of DLP (registered trademark) (Digital Light Processing) system. The pixel of the displayed image corresponds to each minute mirror, and the number of the plurality of minute mirrors is the resolution of the displayed image.

  FIG. 8A shows a case where the laser light 502 scanned by the light modulator 504 by the two-dimensional MEMS mirror 503 is projected on the screen 10. Hereinafter, this state is referred to as an ON state. In the ON state, the laser beam 502 is reflected toward the screen 10 by a plurality of micro mirrors whose inclination angles are controlled.

  FIG. 8B shows a case where the laser beam 502 scanned by the micromirror is not projected on the screen 10. Hereinafter, this state is referred to as an OFF state. In the OFF state, the laser beam 502 is reflected toward the blocking unit 530 that absorbs and blocks the laser beam 502 by the plurality of micro mirrors whose inclination angles are controlled.

  The inclination angles of the plurality of micromirrors are individually controlled, and the above-described ON state and OFF state can be taken with respect to the incident laser beam 502 for each micromirror. Therefore, the inclination angle of each micromirror is controlled at high speed, and the intensity of the laser beam 502 incident on each micromirror is modulated by switching between the ON state and the OFF state at high speed. The intensity of the laser beam 502 scanned by the light modulator 504 by the two-dimensional MEMS mirror 503 is modulated by each micromirror that is individually driven, and the laser beam 502 is projected to display an image.

  In the projector 500 of this embodiment, optical elements such as the polarizing plate, the polarizing beam splitter, and the wire grid polarizing plate used in the above embodiments are unnecessary. Therefore, it is advantageous for downsizing the projector 500, and the structure of the projector 500 can be simplified.

<Sixth Embodiment>
FIG. 9 is a plan view schematically showing a projector according to the sixth embodiment of the present invention. The projector 600 according to the present embodiment includes a laser light source 601 that emits red, green, and blue laser beams 602R, 602G, and 602B in a time division manner. Other configurations are the same as those of the projector 100 according to the first embodiment.

  The laser light source 601 includes a red laser light source 601R that emits red laser light 602R, a green laser light source 601G that emits green laser light 602G, and a blue laser light source 601B that emits blue laser light 602B. The beam diameters of the laser beams 602R, 602G, and 602B of the respective colors are substantially equal and larger than the pixel area of the transmissive liquid crystal panel 605.

  For example, a semiconductor laser is used as the red laser light source 601R and the blue laser light source 601B. As the green laser light source 601G, for example, a combination of a semiconductor laser that emits infrared light and a SHG (Second Harmonic Generation) element is used.

  The laser beams 602R, 602G, and 602B of the respective colors emitted from the laser light sources 601R, 601G, and 601B of the respective colors are emitted toward a dichroic mirror 625 provided inside the laser light source 601. The dichroic mirror 625 is an optical element that reflects light of a predetermined (range) wavelength and transmits light of other wavelengths. By this dichroic mirror 625, the laser beams 602R, 602G, and 602B of the respective colors are appropriately selected and reflected or transmitted. By providing the dichroic mirror 625 at an appropriate position in the laser light source 601, the optical axes of the laser beams 602R, 602G, and 602B of the respective colors emitted from the laser light source 601 are aligned.

[Projector operation]
When the video signal 650 is input to the control unit 607, the control unit 607 detects the red video signal 650R, the green video signal 650G, and the blue video signal 650B from the video signal 650, and outputs them to the liquid crystal driver. To do. The liquid crystal driver applies a voltage to each pixel of the transmissive liquid crystal panel 605 based on the video signals 650R, 650G, and 650B of the respective colors. Further, the control unit 607 outputs the emission signals 655R, 655G, and 655B of the respective colors to the laser light sources 601R, 601G, and 601B of the respective colors. In FIG. 9, the scanning signal output from the control unit 607 to the two-dimensional MEMS mirror 603 is omitted.

FIG. 10 is a diagram for explaining the timing at which the control unit 607 outputs the video signals 650R, 650G, and 650B for each color and the emission signals 655R, 655G, and 655B for each color. FIG. 11 is a diagram showing three-color frames R ₁ , G ₁ , and B ₁ projected onto the screen 10 in accordance with the timing shown in FIG.

  As shown in FIG. 10, the control unit 607 outputs a red video signal 650R to the liquid crystal driver. In synchronization with this, the control unit 607 outputs a red emission signal 655R to the red laser light source 601R via the laser driver. (Step 1). In step 1 of FIG. 10, the state where the red emission signal 655R is output is illustrated as the ON state.

The red laser light source 601R emits red laser light 602R having a constant intensity while receiving the red emission signal 655R. The emitted red laser light 602R is incident on the two-dimensional MEMS mirror 603 and is scanned over the entire pixel of the transmissive liquid crystal panel 605 by the two-dimensional MEMS mirror 603. As a result, the red frame R ₁ created by only the red laser beam 602R shown in FIG.

Next, the control unit 607 outputs the green video signal 650G to the liquid crystal driver, and outputs the green emission signal 655G to the green laser light source 601G via the laser driver so as to synchronize with this (step 2). The green laser light source 601G that has received the green emission signal 655G emits the green laser light 602G. Green laser light 602G is scanned across pixel of the transmissive liquid crystal panel 605 by a two-dimensional MEMS mirror 603, a green frame G ₁ shown in FIG. 11 is projected on the screen 10.

Next, the control unit 607 outputs the blue video signal 650B to the liquid crystal driver and outputs the blue emission signal 655B to the blue laser light source 601B. (Step 3). The blue laser light 602B emitted from the blue laser light source 601B is scanned over the pixels of the transmissive liquid crystal panel 605 by the two-dimensional MEMS mirror 603. As a result, the blue frame B ₁ shown in FIG. 11 is projected onto the screen 10.

By performing the operation from step 1 to step 3 within the time when one frame of the video is displayed, the three-color frames R ₁ , G ₁ , and B ₁ are projected onto the screen 10 in a time division manner, so that the full color Is displayed. The same steps continue after step 4.

The three color frames R ₁ , G ₁ , and B ₁ may be projected a plurality of times within the time when one frame is displayed. For example, a red frame R _1, green frame G _1, blue frame B ₁ is being projected sequentially, red frame R _1, green frame G _1, blue frame B ₁ is being projected sequentially again. That is, a total of six frames of three colors R ₁ , G ₁ , and B ₁ may be projected within a time period during which one frame is displayed. As a result, a full-color image in which the chromaticity changes smoothly can be obtained.

When the three color frames R ₁ , G ₁ , and B ₁ are projected a plurality of times within the time for displaying one frame, a large number of times of scanning the entire pixel of the transmissive liquid crystal panel 605 is required. In this embodiment, since the entire pixel of the transmissive liquid crystal panel 605 can be scanned with a small number of scans, it is easy to project the three color frames R ₁ , G ₁ , and B ₁ multiple times.

Further, since the full-color image is displayed by projecting the three color frames R ₁ , G ₁ , and B ₁ in a time division manner, for example, a color filter, red, green, It is not necessary to provide sub-pixels for displaying blue and blue, respectively. Thereby, the structure of the transmissive liquid crystal panel 605 can be simplified.

  Also in the other embodiments described above, full-color images are displayed by using laser light sources that emit laser beams of three colors as in the present embodiment.

<Modification>
The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  For example, in the projector according to each of the embodiments described above, since the laser beam whose polarization plane is set in one direction is emitted, an image is displayed even if a polarizing plate is not disposed between the light source and the optical modulator. Is done. However, in order to further improve the brightness and contrast of the displayed image, a polarizing plate may be disposed between the light source and the optical modulator, and the polarization plane of the emitted laser light may be further aligned.

  Further, the polarization beam splitter used in the third embodiment and the wire grid polarizing plate used in the fourth embodiment are not limited, and other polarization separators may be used. A combination of a GLV (Grating Light Valve) element and a film that transmits only diffracted light may be used as the light modulator.

  The method of scanning a laser beam two-dimensionally with a two-dimensional MEMS mirror is not limited to that described above. For example, in the first embodiment, the effective pixel area Z of the transmissive liquid crystal panel may be divided into a plurality of areas, and the laser beam 2 may be scanned for each area. In addition, any scanning method may be used as long as the laser light 2 is irradiated to the entire pixels of the transmissive liquid crystal panel 5 within the time for displaying one frame of the image.

  FIG. 12 is a diagram illustrating a modification of the projector 100 according to the first embodiment. In the projector 100, two laser light sources 1a and 1b and two two-dimensional MEMS mirrors 3a and 3b are used.

As shown in Figure 12, the laser beam 2a emitted from the laser light source 1a is a two-dimensional MEMS mirror 3a, it is scanned in the transmission region Z ₁ of the lower half of an effective pixel region Z of the liquid crystal panel 5. Laser beam 2b emitted from the laser light source 1b is a two-dimensional MEMS mirror 3b, it is scanned in the region Z ₂ of the upper half of the effective pixel area Z.

  As described above, a plurality of laser light sources and two-dimensional MEMS mirrors may be used, and laser light may be scanned for each of the divided effective pixel regions. As a result, the entire pixel of the transmissive liquid crystal panel is irradiated with laser light without increasing the scanning speed of each two-dimensional MEMS mirror. A plurality of laser light sources and two-dimensional MEMS mirrors may be used not only in the first embodiment but also in other embodiments.

  The projector described in each embodiment may be used as a front type projector or a rear type projector.

DESCRIPTION OF SYMBOLS 1,301,401,501,601 ... Laser light source 2,302,402,502 ... Laser light 3,303,403,503,603 ... MEMS mirror 4,304,404,504,604 ... Optical modulator 5,605 ... Transmission type liquid crystal panel 6,606 ... Polarizing plate 9 ... Video 100, 200, 300, 400, 500, 600 ... Projector 305,405 ... Reflection type liquid crystal panel 306 ... Polarizing beam splitter 406 ... Wire grid polarizing plate 601R ... Red laser Light source 601G ... Green laser light source 601B ... Blue laser light source 602R ... Red laser light 602G ... Green laser light 602B ... Blue laser light

Claims (8)

A laser light source for emitting laser light;
An optical modulator that modulates the intensity of the laser beam to display an image;
An optical scanner that scans the emitted laser light two-dimensionally toward the optical modulator. The projector according to claim 1,
The light modulator has a plurality of pixels that individually modulate the intensity of the laser light,
The beam diameter of the scanned laser beam is larger than the area of each pixel. The projector according to claim 2,
A projector further comprising a lens system disposed between the laser light source and the optical scanner and configured to make the beam diameter of the emitted laser light larger than the area of each pixel. The projector according to claim 1,
The laser light source emits the laser light having a first polarization plane;
The light modulator is
A transmissive liquid crystal panel capable of transmitting the laser light while rotating the first polarization plane;
A projector comprising: a polarizing plate that transmits the laser light having a second polarization plane different from the first polarization plane out of the laser light transmitted through the transmissive liquid crystal panel. The projector according to claim 1,
The laser light source emits the laser light having a first polarization plane;
The light modulator is
A reflective liquid crystal panel capable of reflecting the laser light while rotating the first polarization plane;
Polarized light that projects the laser light having a second polarization plane different from the first polarization plane out of the laser light that is incident on the reflective liquid crystal panel and reflected by the reflective liquid crystal panel. A projector having a separator. The projector according to claim 1,
The light modulator has a plurality of micromirrors,
The plurality of micromirrors reflect the laser light, and the angle at which the laser light is reflected is controlled to individually modulate the intensity of the laser light. The projector according to claim 1,
The laser light source emits the red, green, and blue laser light in a time-sharing manner,
The light modulator modulates each intensity of the red, green, and blue laser beams. Laser light is emitted toward the optical scanner,
The laser beam is scanned two-dimensionally toward the optical modulator by the optical scanner,
An image display method for displaying an image by modulating the intensity of the laser beam scanned on the optical modulator by the optical modulator.

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