JP2015118359A - Optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection device capable of improving safety in a projection device and reducing speckle due to laser coherency without providing a despeckle element.SOLUTION: The projection device includes: a plurality of laser sources 10 in which drive timing signals are each in synchronization; scan means 25 for scanning a laser beam from the laser source and projecting an image on a projection surface; and a control section 40 which, when the same image is displayed on the projection surface by the plurality of laser sources, controls emission timing of the plurality of laser sources so that a position irradiated with one of the plurality of laser sources is different from a position irradiated with other laser sources. This reduces speckle.

Description

  The present invention relates to a projection apparatus, and more particularly to a projection apparatus that scans a plurality of laser projectors and projects an image on a projection surface.

  In recent years, small-sized laser projectors that can be connected to small-sized information devices such as mobile phones and laptop computers have been used as projection devices. In such a laser projector, a MEMS (Micro Electro Mechanical Systems) mirror may be used to reduce the size of the optical system. Predetermined information is displayed on a projection surface such as a screen by two-dimensionally scanning laser light emitted from a semiconductor laser (hereinafter also referred to as LD) with this MEMS mirror.

  Patent Document 1 discloses a technique for displaying an image on a screen by scanning in the X and Y directions using vibration of a MEMS mirror provided in the projection apparatus using one laser projector. Yes. FIG. 14 is a schematic diagram showing a locus of laser light by the projection apparatus of Patent Document 1. This projection apparatus scans a spot of laser light with a MEMS mirror to form a locus as shown by a dotted line and a solid line in FIG.

  Patent Documents 2 and 3 are documents on a technique for forming an image on a screen using a plurality of projection lights. Patent Document 2 discloses an image display device capable of sharing the scanning of the beam light using a plurality of optical scanning units and displaying a high-quality image in which the joint portion between the scanning regions is not conspicuous. . Patent Document 3 discloses a projection system that forms a composite image on an object by projecting a plurality of partial images onto a stereoscopic (three-dimensional) screen using a plurality of projectors.

  Further, in Patent Document 4, the same scanning line is scanned by two light beams in duplicate, and dot rows with a dot interval d formed by each light beam at that time are each d / 2 in the main scanning direction. There is disclosed an image forming apparatus that shifts to an image. In Patent Document 5, in a light beam scanning method of scanning a light beam on a surface to be scanned by rotating a micromirror, a plurality of light beams having different scanning positions on the surface to be scanned are used. A light beam scanning method is disclosed in which a plurality of light beams are time-divided several times during scanning.

JP 2013-164503 A (page 6-7, FIG. 2) JP 2007-25190 A (page 8-9, FIG. 12) JP 2013-118596 A (page 8-9, FIG. 1) JP 2004-223754 A JP 2005-338512 A

  The technique disclosed in Patent Document 1 is a projection apparatus using one laser projector, and only one laser light source is used. Therefore, in order to obtain a sufficient amount of light with this one laser light source, it is necessary to increase the light amount of the laser light source. However, if the amount of light is increased in one laser light source, it may exceed the safety standard of laser light when it enters the human eye and may affect the function of the eye.

  In addition, when an image is formed by a single laser light source, speckle due to laser coherency may occur, and it may be necessary to provide a separate despeckle element in order to reduce the speckle.

  In Patent Document 2 and Patent Document 3, there is no mention of the image synchronization or composition method of each projector for reducing speckles of the composite projection image by a plurality of projectors. Therefore, the projectors of Patent Document 2 and Patent Document 3 may still cause speckle.

  An object of the present invention is to provide a projection apparatus capable of improving the safety of the projection apparatus and reducing speckles caused by laser coherency.

A projection apparatus according to the present invention includes a plurality of laser light sources each of which synchronizes drive timing signals, a scanning unit that scans laser light from the laser light sources and projects an image on a projection surface, and a plurality of laser light sources When displaying the same image on the projection plane, the position of one of the plurality of laser light sources is different from the position irradiated by the other laser light source. And a control unit for controlling the light emission timing.
In the above projection apparatus, it is preferable that the control unit controls a predetermined pixel on the projection surface so that one laser light source and another laser light source irradiate in different frame periods.
In the above projection apparatus, it is preferable that the control unit simultaneously irradiates different scanning lines on the projection surface with one laser light source and another laser light source.
In the projection apparatus, it is preferable that the control unit irradiates different pixels on the projection surface with one laser light source and another laser light source for a predetermined time.

In the above projection apparatus, it is preferable that the projector further includes a detection unit that detects the distance from the laser light source to the projection surface as depth information, and the control unit controls the light emission timing based on the depth information.
In the above projection apparatus, the laser light source includes a plurality of laser beams having different colors and light emitting points on the same plane, and each projection point of the plurality of laser beams is arranged in a line along the scanning direction of the scanning unit on the projection plane. It is preferable to emit light so as to line up with each other.

In the above projection apparatus, the laser light source can emit each color laser beam having a different color from a plurality of fibers divided for each color, and the projection point of each color laser beam is scanned by the scanning means on the projection surface. It is preferable to further include a fixture that fixes the plurality of fibers so as to be aligned in a line along the direction.
In the above projection apparatus, the scanning unit is preferably a plurality of MEMS scanners provided corresponding to each of the plurality of laser light sources and scanning the projection surface by deflecting the laser light from the corresponding laser light sources. .

  In the above projection apparatus, the plurality of laser light sources can emit a plurality of sets of laser beams each including red, green, and blue laser beams from a plurality of fibers, and projection points of the plurality of sets of laser beams are projection surfaces. It is preferable to further include a fixture for fixing the fibers of the plurality of laser light sources so as to be shifted from each other in a direction crossing the scanning direction of the scanning unit.

  ADVANTAGE OF THE INVENTION According to this invention, the safety | security in a projector can be improved and the projector which can reduce the speckle resulting from the coherency of a laser can be provided.

FIG. 3 is a schematic diagram for explaining a configuration of the projection apparatus 1. 2 is a diagram for explaining a configuration of a laser projector 2. FIG. 1 is a schematic diagram of a MEMS scanner 25. FIG. It is a figure for demonstrating the ferrule 23 and a fiber bundle. It is the figure which showed the modification of the fiber bundle. It is sectional drawing which showed the green laser diode 12 light-emitted green using the SHG element mounted with high integration. It is the figure which showed the scanning line Lp of the 1st laser projector. It is the figure which showed the scanning line Lq of the 2nd laser projector. It is the figure which showed the state which accumulated the scanning line of the 1st laser projector, and the scanning line of the 2nd laser projector. It is the figure which showed the state which accumulated the scanning line Lp of the 1st laser projector, and the scanning line Lq of the 2nd laser projector in the case of the one-side scanning. It is the schematic diagram which showed the scanning line of the 1st laser projector and the scanning line of a 2nd laser projector in a modification. It is a schematic block diagram of the projection apparatus 1 '. It is the figure which showed the example of the positional relationship of the fibers 22a and 22b fixed by the ferrule 23 ', and the scanning lines Lp and Lq by each group RGB laser beam. It is the schematic diagram which showed the locus | trajectory of the laser beam by the conventional projector.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The technical scope of the present invention is not limited to these embodiments.

  FIG. 1 is a schematic diagram for explaining the configuration of the projection apparatus 1. The projection apparatus 1 includes a first laser projector 2a and a second laser projector 2b arranged in parallel, and projects laser light 28 from the respective laser projectors onto the projection surface 50. Hereinafter, the first laser projector 2a and the second laser projector 2b are not distinguished from each other and are also simply referred to as “laser projector 2”.

  The first laser projector 2a is on the host side and has timing control means 60 inside. The second laser projector 2b is on the slave side, and is controlled by receiving a synchronization signal or the like from the first laser projector 2a on the host side. The timing control means 60 controls the light emission timings of the plurality of laser light sources so that the position irradiated by one laser light source among the plurality of laser light sources is different from the position irradiated by another laser light source.

  In the projection apparatus 1, the timing control means 60 transmits a synchronization signal or the like from the host-side laser projector 2 to the slave-side laser projector 2 with one laser projector 2 as a host and the other laser projector 2 as a slave. . However, it is also possible to provide the timing control means 60 independently of the laser projector 2 and to control the laser light scanning position and the light emission timing of the laser projector 2 by the timing control means 60.

  FIG. 2 is a diagram for explaining the configuration of the laser projector 2. Each of the laser projectors 2 includes a laser light source 10, an emitting unit 20, a detecting unit 30, and a control unit 40 as main components. The laser projector 2 outputs the laser light of each color emitted from the laser light source 10 from each of the plurality of fibers 21 bundled by the ferrule 23, and scans in a two-dimensional manner via the oscillating MEMS scanner 25. An image is projected on the projection surface 50.

  The laser light source 10 includes laser diodes (LD) 11, 12, and 13 that emit red (R), green (G), and blue (B) laser beams. In the laser light source 10, the light emission timing, light emission intensity, and the like of each of the laser diodes 11, 12, and 13 are controlled by the control unit 40 according to the image data of the projected image. At this time, since the images are projected on the projection surface 50 by the laser light sources 10 of the two laser projectors 2, it is possible to reduce the emission intensity of the laser light sources 10 per unit.

  The emission unit 20 emits each color laser beam from the laser light source 10 toward the projection surface 50. The emitting unit 20 includes a plurality of fibers 21, a ferrule 23, a projection lens 24, a MEMS scanner 25, a MEMS driver 26, and a shielding unit 29.

  The plurality of fibers 21 include a fiber for transmitting each color laser beam from the laser light source 10 and a dummy fiber (not shown). Each fiber is, for example, a single mode optical fiber. Hereinafter, the fibers that transmit the R, G, and B laser beams from the laser diodes 11, 12, and 13 are referred to as an R fiber, a G fiber, and a B fiber, respectively. These fibers are collectively referred to as RGB fibers. The dummy fiber is called D fiber. The laser projector 2 has one R fiber, one G fiber, and one B fiber, and a plurality of D fibers.

  The ferrule 23 is an example of a fixture, and binds and fixes an R fiber, a G fiber, a B fiber, and a D fiber at the end opposite to the laser light source 10. The RGB laser beams are emitted from the emission end face of each fiber 21 at the end of the ferrule 23.

  The projection lens 24 shapes so that each color laser beam emitted from the emission end face of each fiber 21 is irradiated to the MEMS scanner 25.

  The MEMS scanner 25 is an example of a scanning unit, and is swung at a high speed, for example, in the horizontal direction and the vertical direction by the MEMS driver 26. In the horizontal direction, the MEMS scanner 25 is resonantly driven at, for example, about 20 KHz, and the scanning angle changes with time in a sine wave shape. In the vertical direction, the MEMS scanner 25 is driven at, for example, 60 Hz by a sawtooth forced drive, and its scanning angle changes with time in a sawtooth manner. As a result, the MEMS scanner 25 scans each color laser beam from the projection lens 24 two-dimensionally on the projection surface 50.

  The MEMS driver 26 drives the MEMS scanner 25 according to the control data from the control unit 40, and swings the MEMS scanner 25 in the horizontal direction and the vertical direction at high speed. As the driving method, any of an electrostatic method, an electromagnetic method, a piezo method, and the like may be used. Different driving methods may be combined for horizontal scanning and vertical scanning.

  The shielding unit 29 is a frame having a rectangular opening 29 a (see FIG. 1), and shields the periphery of the scanning region of the laser light 28 scanned by the MEMS scanner 25. The laser beam 28 passing through the opening 29 a of the shielding unit 29 displays an image on the projection surface 50.

  The detection unit 30 detects the distance (hereinafter referred to as depth information) from the emission point of the laser light at the emission unit 20 to the projection plane 50. The detection unit 30 includes an infrared irradiation unit 31 and an infrared detection unit 32. The infrared irradiation unit 31 irradiates infrared light in the space where the laser projector 2 is installed. The infrared detection unit 32 is, for example, an infrared camera, and receives reflected light reflected by an object in the space, a floor, a wall, or the like, which is emitted from the infrared irradiation unit 31. The detection unit 30 uses, for example, a time-of-flight (TOF) method, and measures the depth of flight by measuring the flight time of light from when the infrared irradiation unit 31 emits infrared rays until the infrared detection unit 32 receives reflected light. Detect information. The detection unit 30 notifies the control unit 40 of the depth information. In the projection apparatus 1, the detection unit 30 is installed separately from the laser light source 10. As will be described later, a laser diode that irradiates infrared rays or the like is provided together with the laser light source 10, and a fiber for infrared rays or the like is provided. It is also possible to detect depth information.

  The control unit 40 controls the operation of the laser projector 2. The control unit 40 includes a CPU 41, a RAM 42, a ROM 43, and an I / O 44. The I / O 44 is an interface for transferring data between the laser light source 10, the emission unit 20, and the detection unit 30. The control unit 40 controls the light emission timing of the laser light source 10 as described later according to the image data and the depth information acquired from the detection unit 30. Further, the control unit 40 controls the emitting unit 20 to project the laser light 28 onto the projection surface 50.

  Although not shown in FIG. 2, the laser projector 2 serving as a host has timing control means 60 (see FIG. 1) inside, and has a function of transmitting a synchronization signal to the laser projector 2 serving as a slave. . On the contrary, in the laser projector 2 serving as a slave, the control unit 40 has a function of receiving a synchronization signal from the laser projector 2 serving as a host. The function of the timing control unit 60 may be realized by the control unit 40 of the laser projector 2 on the host side, or the timing control unit 60 may be a control unit different from the control unit 40.

  When each laser projector 2 swings the MEMS scanner 25, the projection point 51 of the laser light 28 moves in the direction of the arrow in FIG. 1 to draw a sinusoidal locus L1 indicated by a broken line and a solid line. The locus L1 of the projection point 51 scans the projection surface 50 in a two-dimensional manner while repeatedly reciprocating in the horizontal direction on the projection surface 50.

  In FIG. 1, the horizontal direction is the X direction and the vertical direction is the Y direction. The laser beam 28 is scanned within a rectangle surrounded by the X-direction display width A1 and the Y-direction display width B1. The locus L1 of the projection point 51 moves in the direction of the arrow along a sine wave curve indicated by a broken line and a solid line with the point P1 as a starting point. The locus L1 periodically repeats the movement of drawing a curve in the X direction like the locus La1 and La2 in the opening 29a and drawing a curve like the locus Lb1 and Lb2 on the shielding part 29. When the locus L1 reaches the lowermost point P2, the locus L1 moves upward along the sinusoidal curves Lc1 and Lc2 indicated by fine dotted lines and returns to the starting point P1. Thereby, drawing for one screen is completed. Each laser projector 2 continuously projects images by repeating the above operation.

  The scanning in each laser projector 2 is as described above. In the projection apparatus 1, the timing control means 60 in the first laser projector 2a serving as the host transmits a synchronization signal to the second laser projector 2b serving as the slave, and the scanning position and light emission timing of the second laser projector 2b. To control.

  FIG. 3 is a schematic diagram of the MEMS scanner 25. The MEMS scanner 25 has a structure in which a micro mirror 251 serving as a reflection surface is supported by torsion bars 252 and 253. When the torsion bar 252 is twisted, the micro mirror 251 swings in the horizontal direction (X direction) with the shaft 254 as the central axis. As a result, the normal line of the reflecting surface of the micromirror 251 changes in the X direction, so that the reflection angle of the laser light incident on the micromirror 251 changes in the X direction. Further, the micro mirror 251 swings in the vertical direction (Y direction) about the axis 255 orthogonal to the axis 254 as the torsion bar 253 is twisted. As a result, the normal line of the reflecting surface of the micromirror 251 changes in the Y direction, so that the reflection angle of the laser light incident on the micromirror 251 changes in the Y direction. In this way, the laser beam is scanned two-dimensionally by the MEMS scanner 25.

  4A to 4C are diagrams for explaining the ferrule 23 and the fiber bundle. FIG. 4A is a cutaway perspective view of the ferrule 23. FIG. 4B is a cross-sectional view of the fiber bundle fixed by the ferrule 23. FIG. 4C is a diagram for explaining which fiber each fiber 21 shown in FIG. 4B is.

  The ferrule 23 is configured in a cylindrical shape by, for example, zirconia. The ferrule 23 fixes a total of seven fibers, one R fiber 21r, one G fiber 21g, and one B fiber 21b, and four D fibers 21d, in a cylindrical through hole 23a.

  Each fiber 21 has a core 211 and a clad 212 covering the periphery of the core. The core 211 is formed at the center of the core of the fiber 21 and transmits laser light. The clad 212 is formed on the outer periphery of the core 211 and has a refractive index lower than that of the core 211. Laser diodes 11, 12, and 13 are connected to each of the RGB fibers at an end (not shown) opposite to the end shown in FIG. And each color laser beam is radiate | emitted from each edge part of the RGB fiber shown to FIG. 4 (A).

  Six fibers other than the G fiber 21g are arranged concentrically so as to surround the G fiber 21g serving as the center. Furthermore, the R fiber 21r, the G fiber 21g, and the B fiber 21b are arranged so as to be aligned in the A direction in FIG. The diameter of each fiber 21 is substantially equal, and the distance between two adjacent cores 211 is also substantially equal. The ferrule 23 fixes the fiber bundle bundled in such an arrangement. The ferrule 23 is fixed with respect to the laser projector 2. That is, the arrangement of the fibers 21 is fixed for each laser projector (for each device).

  As described above, in the laser projector 2, the light from each of the RGB fibers is not coupled to one fiber, but a plurality of fibers 21 including the RGB fibers are simply bundled to form a fiber bundle and fixed by the ferrule 23. Thereby, in the laser projector 2, the use efficiency of a laser beam is improved by suppressing the influence between the fibers which may occur in the fused fiber.

  The ferrule 23 may be made of other materials such as stainless steel. Further, the fiber bundle may be fixed using a fixing tool different from the ferrule 23. Furthermore, a combiner can also be used.

  Moreover, the detection part 30 of FIG. 2 can also be integrated in a fiber bundle. FIG. 5A and FIG. 5B are diagrams showing modifications of the fiber bundle. The combinations of the plurality of fibers 21 fixed by the ferrule 23 include, for example, two types shown in FIGS. 5A and 5B in addition to those shown in FIG. 4C.

  FIG. 5A shows a modification in which one of the dummy D fibers is a fiber that outputs infrared rays for detecting depth information. Hereinafter, this fiber is referred to as an IR fiber. An IR fiber is an example of an infrared irradiation fiber. In this modification, the position of the IR fiber may be any of the four locations (other than the RGB fiber) where the D fiber was present.

  In the case of FIG. 5A, a laser diode (LD) (not shown) for irradiating infrared rays is provided together with the laser light source 10. Then, before projecting the image, the infrared rays generated by the laser diode are irradiated from the end of the ferrule 23 through the IR fiber before projecting the image. The depth information is detected by the infrared detection unit 32 receiving the reflected infrared light emitted from the IR fiber. In this case, it is not necessary to provide the infrared irradiation unit 31 of the detection unit 30 externally, and the detection unit 30 may include only the infrared detection unit 32.

  FIG. 5B shows a modified example in which the three D fibers shown in FIG. 5A are fibers to which infrared reflected light from the IR fiber is input. Hereinafter, this fiber is referred to as a PD fiber. The PD fiber is an example of an infrared receiving fiber. In this modification, a photodiode (PD) (not shown) is provided at the end of the PD fiber opposite to the ferrule 23. Of the reflected light reflected by the projection surface, only a solid angle corresponding to the size of the MEMS scanner 25 enters the respective PD fibers and is received by the photodiode.

  In the case of FIG. 5B, the depth information is detected when the three PD fibers receive the infrared reflected light emitted from the IR fiber. That is, the depth information is detected not by the external detection unit 30 but by the IR fiber and the PD fiber fixed together with the ferrule 23 together with the RGB fiber. As described above, when the IR fiber and the PD fiber for detecting depth information are bundled together with the ferrule 23 together with RGB, it is not necessary to provide the external detection unit 30, so that the laser projector 2 can be further downsized. become.

  Further, in addition to the above fiber, a fiber connected to a visible color detection PD may be bundled. Further, a fiber bundle of laser light including other than RGB may be replaced with a multi-core fiber.

  Next, a laser light source used in the projection apparatus 1 that is a scanning projection display apparatus will be described.

  In the laser light source 10, a direct-emitting laser diode is used for the red laser diode 11 and the blue laser diode 13, and an SHG laser using an excitation semiconductor laser and an SHG (Second Harmonic Generation) element is used for the green laser diode 12. use. However, SHG lasers may be used for all three colors.

  FIG. 6 is a cross-sectional view showing the green laser diode 12 that is mounted with high integration and emits green light using an SHG element.

  The green laser diode 12 includes a Si platform 70, a near-infrared LD 71 for excitation, a waveguide type SHG element 73, an optical fiber 75, a base portion 78, and a constant temperature block 79. The LD 71, the SHG element 73 and the optical fiber 75 are mounted on the Si platform 70. The constant temperature block 79 is a Peltier element, for example, and is fixed to the lower surface of the Si platform 70 via a base portion 78 made of a metal material having good thermal conductivity. The near-infrared LD 71 is an SLD (Super Luminescence Diode) type LD having a broad emission spectrum, and is used by forming an external resonance circuit in combination with a grating element and causing laser oscillation at a specific wavelength. The Si platform 70 is formed by forming wiring patterns, lands, logic LSIs, temperature sensors and the like on a Si substrate, and further forming optical wirings and waveguides serving as circuits.

  In the green laser diode 12, the LD 71 and the SHG element 73 are positioned and joined to the upper surface of the Si platform 70 so that the waveguides 72 and 74 of the LD 71 and the SHG element 73 are optically coupled. The optical fiber 75 is also positioned and bonded so that the core 76 and the waveguide 74 of the SHG element 73 are optically coupled.

  The LD 71 and the SHG element 73 are arranged and fixed extremely close to each other, and the near infrared light emitted from the waveguide 72 of the LD 71 is incident on the waveguide 74 of the SHG element 73 by direct optical coupling, and green light is emitted in the waveguide 74. Is output from the SHG element 73. The output green light is further guided to the core 76 of the optical fiber 75. On the other hand, near-infrared light transmitted without being converted is reflected by an FBG (Fiber Bragg Grating) type reflection element 77 incorporated in the optical fiber 75 and selected by an external resonator formed by the LD 71 and the FBG reflection element 77. Is incident on the SHG element 73 at the resonant wavelength reflected. In this way, the green laser diode 12 increases the conversion efficiency and emits green converted light.

  Next, a projection method using a plurality of laser projectors 2 will be described.

  A plurality of laser projectors 2 adjusted so that arbitrary patterns of RGB and NIR (Near Infra-Red) can be projected on the same area from the laser light source 10 and the emitting unit 20 having a multiplexed structure such as a fiber bundle type, Installed with respect to the projection plane 50. Each laser projector 2 has a function of acquiring a NIR projection pattern such as an M-Array with an NIR camera and calculating depth information by triangulation in the detection unit 30.

  First, the reference point is projected from the first laser projector 2a on the host side to the projection position of the projection plane 50. As the projection surface 50, a screen object can be used, and a palm or a table top that is close to each other can be used.

  Next, the reference point projected on the projection position of the projection surface 50 is acquired by the camera provided in the second laser projector 2b on the slave side, and the reference point on the slave side is set.

  In the detection unit 30 of the first laser projector 2a on the host side, depth sensing is performed to obtain geometric correction data related to depth information.

  In addition, the sensing unit 30 of the second laser projector 2b on the slave side performs depth sensing to acquire geometric correction data related to depth information.

  The control unit 40 of the first laser projector 2a on the host side performs geometric correction based on the geometric correction data, and projects the corrected grid pattern onto the projection plane 50.

  Next, the grid pattern projected on the host side is acquired in the second laser projector 2b on the slave side.

  Next, the control unit 40 of the second laser projector 2b corrects the grid pattern on the slave side so as to overlap the grid pattern projected on the host side acquired on the slave side.

  Then, the control units 40 of the first laser projector 2a and the second laser projector 2b project the RGB images corrected by the correction patterns on both the host side and the slave side onto the projection plane 50. At this time, the host and the slave drive the projection timing synchronously so that the host side pattern and the slave side pattern do not interfere with each other. As described above, the timing control unit 60 of the projection apparatus 1 synchronizes the projection timing of the host and the slave by controlling the light emission timing of the laser light source of each laser projector based on the depth information acquired by depth sensing. Drive.

  Next, a method of superimposing display images from the two laser projectors 2, that is, display pixels will be described.

  The projection device 1 simultaneously projects images that interpolate the odd and even lines of the same image / video from the two laser projectors 2 like interlace. At this time, the first laser projector 2a and the second laser projector 2b are set so that the phase of the resonance vibration direction is shifted by 180 ° and the irradiation positions are different from each other. Since two laser projectors 2 scan at the same time and interpolate odd and even lines of the same image / video, the number of scanning lines in the vertical direction is larger than that of a single laser projector 2. Is substantially doubled.

  FIG. 7 is a diagram showing the scanning line Lp of the first laser projector, and FIG. 8 is a diagram showing the scanning line Lq of the second laser projector. FIG. 9 is a diagram showing a state in which the scanning lines of the first laser projector and the scanning lines of the second laser projector are overlapped. That is, the irradiation position of the image (pixel) displayed by the first laser projector 2a and the image (pixel) displayed by the second laser projector 2b are different, but the same image is displayed. Yes. In the case of this method, when scanning is performed in a reciprocating manner, the scanning lines overlap in the vicinity of the center, so that the effective resolution cannot be increased. Therefore, it is preferable that each laser projector 2 perform one-side scanning with the laser light source 10 turned off in La2 and the like in FIG.

  FIG. 10 is a diagram showing a state in which the scanning line Lp of the first laser projector and the scanning line Lq of the second laser projector are overlapped in the case of one-side scanning. Of the scanning lines Lp and Lq, it is assumed that the laser light source 10 is turned on (on) in the solid line portion and the laser light source 10 is turned off (off) in the broken line portion.

  When the images of the two laser projectors 2 are superimposed with a phase shift of 180 ° with respect to the frame period on the resonance side, the other laser projector 2 is interpolated so as to interpolate the scanning lines of one laser projector 2 as shown in FIG. The scanning lines overlap. For this reason, compared with the case where there is one laser projector 2, the number of vertical scanning lines at one-side scanning is doubled, and the vertical resolution can be doubled. In addition, since the scanning lines are substantially parallel in the effective display area because of one-side scanning, the scanning lines do not overlap each other.

  FIG. 11A and FIG. 11B are schematic views showing the scanning lines of the first laser projector and the second laser projector in the modification. In this modification, so-called interlace scanning is performed, and the irradiation positions of the two laser projectors are set to be different from each other.

  As shown in FIG. 11A, in the odd-numbered frames, the projection apparatus 1 scans the odd-numbered scanning lines with the first laser projector 2a (Lo1), and the even-numbered frames with the second laser projector 2b. Are scanned (Lo2). In addition, as shown in FIG. 11B, in the even-numbered frame, the projection apparatus 1 scans the odd-numbered scanning lines by the second laser projector 2b (Le2), and the first laser projector 2a The even-numbered scanning lines are scanned (Le1). That is, the timing control means 60 controls the laser light sources of the two laser projectors 2 to irradiate each pixel on the projection plane in different frame periods.

  In the example shown in FIGS. 10 to 11A, the timing control unit 60 controls the laser light sources of the two laser projectors 2 to simultaneously irradiate different scanning lines on the projection surface. Further, in the example shown in FIGS. 10 to 11A, the timing control means 60 is configured to detect the laser light sources of the two laser projectors 2 in the irradiation time necessary for one-side scanning among the beam trajectories scanned continuously. Control is performed so that different pixels on the projection surface are irradiated.

  By performing the scanning as described above, the resolution in the vertical direction is doubled, and the image from the first laser projector 2a and the image from the second laser projector 2b are alternately placed at the same position on the projection surface. Therefore, it is possible to multiplex angles by irradiating the same part from different positions, and speckles can be reduced by the square root (1 / √2) of multiplicity (2 in the case of this modification). It becomes. Note that the present modification can also be applied to a projection apparatus using three or more laser projectors.

  As a further modification of the projection apparatus 1, the same image or video can be projected by shifting the horizontal synchronization signal by one pixel between one laser projector 2 and the other laser projector 2. That is, the irradiation position is shifted by one pixel between the two laser projectors 2. Thereby, the resolution in the horizontal direction can be improved. At this time, if the frames are synchronized, scanning may be performed with the pixels shifted.

  In the projection apparatus 1 and its modification, the projection is performed on the projection plane 50 from the two laser projectors 2, but the projection may be performed on the projection plane 50 using a larger number of laser projectors 2. In addition, although the MEMS scanner 25 is used in the laser projector 2, LCOS (Liquid Crystal on Silicon) may be used.

  In the projection apparatus 1 and its modification, since the projection is performed on the projection surface from a plurality of laser projectors having independent light sources, speckle caused by laser coherency can be reduced. In particular, since laser beams are projected at different angles from a plurality of laser projectors, speckle reduction by angle multiplexing is possible. Further, since the image is formed by the laser beams from a plurality of laser projectors, the light amount of the laser projectors per unit for obtaining a predetermined light amount can be reduced. For this reason, it is possible to improve safety such as when laser light enters the eye.

  The projection apparatus 1 includes a plurality of laser projectors 2, and each laser projector 2 includes a laser light source 10 and a MEMS scanner 25. However, the projection apparatus can be realized by a single laser projector having a plurality of sets of RGB laser light sources and one scanning unit. Hereinafter, such a projection apparatus will be described.

  FIG. 12 is a schematic configuration diagram of the projection apparatus 1 ′. The projection apparatus 1 ′ is composed of one laser projector similar to the laser projector 2 shown in FIG. 2, and includes a laser light source 10 ′, an emission unit 20 ′, a detection unit 30, and a control unit 40 as main components. As a component. About the detection part 30 and the control part 40, since it is the same as that of the laser projector 2, description is abbreviate | omitted. The control unit 40 of the projection apparatus 1 ′ controls the light emission timings of the plurality of laser light sources so that the position irradiated by one laser light source among the plurality of laser light sources is different from the position irradiated by another laser light source. To do.

  The laser light source 10 ′ includes laser diodes 11 a, 12 a and 13 a and laser diodes 11 b, 12 b and 13 b as two sets of RGB laser light sources, and further, a fused RGB that combines the RGB laser lights of each set. It has combiners 15a and 15b. The laser diodes 11a and 11b emit red laser light, the laser diodes 12a and 12b emit green laser light, and the laser diodes 13a and 13b emit blue laser light, respectively. The RGB laser beams from the laser diodes 11a to 13a are combined by a fusion type RGB combiner 15a, and the RGB laser beams from the laser diodes 11b to 13b are combined by a fusion type RGB combiner 15b.

  The emission unit 20 ′ has fibers 22a and 22b, a ferrule 23 ′, a projection lens 24, and a MEMS scanner 25 as main components, and projects two sets of RGB laser light from the laser light source 10 ′. It emits toward 50. Since the projection lens 24 and the MEMS scanner 25 are the same as those of the laser projector 2, description thereof will be omitted. Although not shown, the emission unit 20 ′ also includes a MEMS driver similar to that of the emission unit 20 of FIG. 2 and a shielding unit.

  The fibers 22a and 22b respectively guide the respective sets of RGB laser beams combined by the fusion type RGB combiners 15a and 15b. The ferrule 23 ′ is an example of a fixture, and has a cylindrical shape like the ferrule 23 shown in FIG. The ferrule 23 'bundles and fixes the fibers 22a and 22b at the end opposite to the laser light source 10'. As shown in FIG. 12, the fibers 22a and 22b are fixed at different positions on the circular cross section of the ferrule 23 '. The RGB laser light of each color is emitted from the emission end faces of the fibers 22a and 22b at the end of the ferrule 23 '.

  Instead of using the fusion type RGB combiners 15a and 15b, a plurality of sets of R fiber, G fiber, and B fiber that respectively guide the RGB laser light may be bundled by the ferrule 23 'to form a fiber bundle. The laser light source 10 'may be provided with three or more sets of RGB laser light sources, and three or more sets of RGB laser light may be emitted from the end of the ferrule 23'.

  FIG. 13 is a diagram showing an example of the positional relationship between the fibers 22a and 22b fixed by the ferrule 23 'and the scanning lines Lp and Lq by each set of RGB laser beams. In the projection apparatus 1 ′, as indicated by an arrow C in FIG. 13, by rotating the ferrule 23 ′ around the optical axis, the scanning line Lp by the RGB laser light from the fiber 22a and the RGB laser light from the fiber 22b are obtained. The distance from the scanning line Lq is adjusted. The ferrule 23 ′ fixes the fibers 22 a and 22 b so that the projection points of the two sets of laser light are shifted on the projection plane 50 in the vertical scanning direction (direction intersecting the horizontal scanning direction) of the MEMS scanner 25. Thus, in the projection apparatus 1 ′, it is possible to optimize the interval between the scanning lines Lp and Lq by the two sets of RGB laser light by finely adjusting the angle of the fiber bundle formed by the ferrule 23 ′. Become.

  The two sets of RGB laser light scanning by the projection apparatus 1 ′ are preferably single-sided scanning as in the case of the projection apparatus 1 described above with reference to FIGS. 10 to 11B. As shown in FIG. 13, since the scanning lines are shifted in the vertical scanning direction (Y direction) by the rotation of the ferrule 23 ', the scanning lines of the two sets of RGB laser light do not overlap each other if one-side scanning is performed.

  Further, similarly to the projection apparatus 1, the projection apparatus 1 'also performs interlace scanning as shown in FIGS. 11 (A) and 11 (B). That is, in the odd-numbered frame, the projection device 1 ′ scans the odd-numbered scanning lines with the laser diodes 11a to 13a (Lo1), and scans the even-numbered scanning lines with the laser diodes 11b to 13b (Lo2). At the same time, in the even-numbered frame, the odd-numbered scanning lines are scanned by the laser diodes 11b to 13b (Le2), and the even-numbered scanning lines are scanned by the laser diodes 11a to 13a (Le1). In other words, the control unit 40 of the projection apparatus 1 ′ causes the two sets of RGB laser light to irradiate different scanning lines on the projection plane 50 at the same time, and irradiate each pixel on the projection plane 50 in different frame periods. The light emission of the laser light source 10 ′ is controlled. In addition, the control unit 40 of the projection apparatus 1 ′ allows the laser diodes 11a to 13a and the laser diodes 11b to 13b to be different pixels on the projection surface during the irradiation time required for one-side scanning among the continuously scanned beam trajectories. Control to irradiate.

  As described above, the projection apparatus 1 ′ uses the laser light sources 10 ′, which are a plurality of sets of RGB laser light sources, and scans by shifting the projection points of the RGB laser beams of each set in the vertical scanning direction (Y direction). The number of alternating scanning lines in the Y direction is increased. In the projection apparatus 1 ′, the interval between the scanning lines by the two sets of RGB laser light can be finely adjusted by the rotation angle of the ferrule 23 ′, so that higher resolution in the vertical scanning direction can be easily realized as compared with the projection apparatus 1. it can. It should be noted that the deviation in the horizontal scanning direction (X direction) of the projection point caused by each set of RGB laser light can be canceled by moving the emission timing of each laser diode back and forth.

  Further, in the projection apparatus 1 ′, since a plurality of sets of RGB laser light sources are projected onto the projection surface, speckles can be reduced depending on the combination of lasers used, for example, using lasers of the same color with slightly different wavelengths. . In addition, since an image is formed by laser beams from a plurality of sets of RGB laser light sources, it is also possible to reduce the amount of light of the RGB laser light sources per set for obtaining a predetermined amount of light. Instantaneously, the beam spots from the two light sources are scanning different positions. For this reason, it is possible to improve safety such as when laser light enters the eye.

  Since the projection apparatus 1 ′ can increase the number of scanning lines by the multiplicity of the RGB laser light source, it can be applied as an optical engine such as a light field display (Light Field Display). In the conventional configuration, a plurality of pico projectors are arranged in the horizontal direction and the vertical direction to form a light field. However, this makes it difficult to simultaneously reduce the size and increase the definition of the device and increase the manufacturing cost. It was. However, since the projection apparatus 1 ′ can reduce the size and definition of the apparatus itself, it can be applied to a light field display or the like.

  In addition to the fibers 21, 22 a, and 22 b, the ferrules 23 and 23 ′ also bundle fibers that guide light of wavelengths other than RGB, and in addition to the RGB laser light from the ends of the ferrules 23 and 23 ′, For example, near infrared rays or visible light with other wavelengths may be emitted together.

DESCRIPTION OF SYMBOLS 1,1 'Projection apparatus 2 Laser projector 2a 1st laser projector 2b 2nd laser projector 10, 10' Laser light source 11, 11a, 11b Red laser diode 12, 12a, 12b Green laser diode 13, 13a, 13b Blue laser Diodes 15a, 15b Fusion type RGB combiner 20, 20 ′ Emitting part 21, 21r, 21g, 21b, 21d, 22a, 22b Fiber 211 Core 212 Clad 23, 23 ′ Ferrule 24 Projection lens 25 MEMS scanner 251 Micro mirror 252, 253 Torsion bar 254, 255 axis 26 MEMS driver 28 laser light 29 shielding unit 30 detection unit 31 infrared irradiation unit 32 infrared detection unit 40 control unit 41 CPU
42 RAM
43 ROM
44 I / O
50 Projection surface 51 Projection point 60 Timing control means 70 Si platform 71 Near infrared LD
72, 74 Waveguide 73 SHG element 75 Optical fiber 76 Core 77 FBG reflection element 78 Base part 79 Constant temperature block

Claims (9)

A plurality of laser light sources each synchronizing drive timing signals;
Scanning means for projecting an image on a projection surface by scanning laser light from the laser light source;
When the plurality of laser light sources display the same image on the projection plane, a position irradiated by one laser light source among the plurality of laser light sources is made different from a position irradiated by another laser light source. A control unit for controlling the light emission timing of the plurality of laser light sources;
A projection apparatus comprising:   The projection apparatus according to claim 1, wherein the control unit controls a predetermined pixel on the projection surface to irradiate the one laser light source and the other laser light source in different frame periods.   The projection apparatus according to claim 1, wherein the control unit simultaneously irradiates different scanning lines on the projection plane by the one laser light source and the other laser light source.   The projection apparatus according to claim 1, wherein the control unit irradiates different pixels on the projection surface with the one laser light source and the other laser light source at a predetermined time. A detector that detects the distance from the laser light source to the projection plane as depth information;
The projection device according to claim 1, wherein the control unit controls the light emission timing based on the depth information.   The laser light source includes a plurality of laser beams having different colors and light emitting points on the same plane, and projection points of the plurality of laser beams are arranged in a line along the scanning direction of the scanning unit on the projection plane. The projection apparatus according to any one of claims 1 to 5, which emits light like this. The laser light source can emit each color laser light having a different color from a plurality of fibers divided for each color,
The projection apparatus according to claim 6, further comprising a fixture that fixes the plurality of fibers so that the projection points of the respective color laser beams are arranged in a line along the scanning direction of the scanning unit on the projection surface.   The scanning means is a plurality of MEMS scanners provided corresponding to each of the plurality of laser light sources and scanning the projection surface by deflecting laser light from the corresponding laser light sources. The projection device according to any one of the above. The plurality of laser light sources are capable of emitting a plurality of sets of laser beams each including red, green and blue laser beams from a plurality of fibers,
The apparatus further comprises a fixture for fixing the fibers of the plurality of laser light sources so that projection points of the plurality of sets of laser beams are shifted from each other in a direction intersecting a scanning direction of the scanning unit on the projection surface. 5. The projection device according to any one of 4.

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