JP2017143014A - Light source device and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate various kinds of optical adjustment in a light source device using a laser light source.SOLUTION: A light source device includes: a laser light source emitting each of red, blue and green laser lights; a first collimator module (204), a second collimator module (205) and a third collimator module (206) which perform outgoing radiation angle adjustment and focus adjustment of each of the laser lights; a first shift module (207), a second shift module (208) and a third shift module (209) which perform position adjustment of each laser light; and a first dichroic mirror (210), a second dichroic mirror (211) and a third dichroic mirror (212) which emit each of the laser lights to a prescribed direction.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a light source device and an image display device using the light source device, and is suitable for, for example, a light source device using a laser light source and an image display device for displaying an image formed by an image forming unit using the light source device. is there.

  Laser display devices that project images onto the screen using laser light such as red, blue, and green, and recently, surface reflection (or half mirror) on glass surfaces and free-form surface mirrors Development of an image display device that displays an image in a space by using a virtual image optical system in combination with the above has progressed.

  In particular, application to an image display device called a head-up display mounted on a moving body such as a passenger car is expected. For example, in a head-up display mounted on a passenger car, light modulated by image information is projected toward a windshield (front glass), and the reflected light is irradiated to the eyes of the driver.

  As a result, the driver can see a virtual image of the image in front of the windshield. For example, the vehicle speed, temperature, etc. are displayed as a virtual image. Recently, it has been considered to display a navigation image or an image that alerts a driver of a real passerby as a virtual image.

  In the head-up display, a laser light source such as a semiconductor laser can be used as a light source. In this configuration, the laser beam scans the screen while the laser beam is modulated in accordance with the video signal. On the screen, the laser light is diffused and the area of the light irradiated to the driver's eyes is expanded. As a result, even if the driver moves his head to some extent, the eyes do not come out of the irradiation area, and the driver can see the image (virtual image) well and stably.

  By using a laser light source, the optical system that scans the laser beam on the screen can be miniaturized, and in combination with a virtual image optical system having a large optical magnification, a large virtual image can be displayed despite the smaller body size. Therefore, the effect of increasing the number of models equipped with a head-up display is expected.

  The following Patent Document 1 is an image projection apparatus for projecting a two-dimensional color image, and has a support, a laser assembly for emitting a plurality of laser beams having different wavelengths, and a working distance from the support. A scanner for sweeping the pattern of scan lines in space, a controller for generating an image by making selected pixels appear illuminated by the laser beam, and focusing the laser beam approximately together. And an optical assembly for forming a composite beam directed to the scanner by linear alignment.

Special table 2008-529069 gazette

  In a light source device and an image display device, it is necessary to adjust laser light such as red, blue and green emitted from a light source such as a semiconductor laser. Specifically, it is necessary to make the emission angle and the optical axis center coincide with each other so that the red, blue, and green laser beams become one point on the projection surface, and focus adjustment and the like must be performed carefully. If these various optical adjustments are not made accurately, when an image is displayed from the image display device, the light emission points of the respective colors may be shifted to cause the colors to appear to be separated or to become blurred images. .

  In addition, due to variations in mounting of laser diodes or variations in flatness of scanning mirrors, the focus position of the laser beam varies from color to color, or individual variations occur, resulting in degradation of the display image. There arises a problem that the quality of the displayed image varies from individual to individual.

  In order to solve the above-described problems, a light source device of the present invention includes a laser light source that emits laser light, and a first adjustment mechanism that adjusts a laser light emission angle and a focus by receiving the laser light from the laser light source. A laser beam from the first adjustment mechanism is incident, a second adjustment mechanism for adjusting the position of the incident laser beam, a laser beam from the second adjustment mechanism is incident, and the incident laser beam is And a mirror that emits light in a predetermined direction.

  An image display device according to the present invention includes the light source device.

  According to the image display device of the present invention, the laser beam emission angle adjustment and the focus adjustment can be performed by the first adjustment mechanism, and the position adjustment of the laser beam can be performed by the second adjustment mechanism. And is easy to adjust.

  The effects and significance of the present invention will become more apparent from the following description of embodiments. However, the embodiment described below is merely an example when the present invention is implemented, and the present invention is not limited to what is described in the following embodiment.

FIGS. 1A and 1B are diagrams illustrating a usage pattern of the image display device according to the embodiment. FIG. 2 is a diagram illustrating a schematic configuration of the image display apparatus according to the embodiment. FIG. 3 is a schematic diagram illustrating a schematic configuration of the optical module (light source device) according to the embodiment. FIG. 4 is a perspective view showing an appearance of the optical module (light source device) according to the embodiment. FIG. 5 is a perspective view showing the inside of the optical module (light source device) according to the embodiment. FIG. 6 is a perspective view showing an appearance of a collimator module in the optical module (light source device) according to the embodiment. FIG. 7 is an exploded perspective view showing the configuration of the collimator module in the optical module (light source device) according to the embodiment. FIG. 8 is a perspective view showing a part of the internal structure of the optical module (light source device) according to the embodiment. FIGS. 9A and 9B are cross-sectional views showing how the collimator module is mounted in the optical module (light source device) according to the embodiment. FIG. 10 is a perspective view showing an appearance of the shift module in the optical module (light source device) according to the embodiment. FIG. 11 is an exploded perspective view showing the configuration of the shift module in the optical module (light source device) according to the embodiment. FIG. 12 is a schematic diagram illustrating the operation of the shift module in the optical module (light source device) according to the embodiment. FIG. 13 is a perspective view showing a partial configuration of the optical module (light source device) according to the embodiment. FIG. 14A is a diagram showing the condensing positions of red light, green light, and blue light in the conventional configuration, and FIG. 14B is the condensing positions of red light, green light, and blue light in the embodiment. FIG.

  Hereinafter, a light source device and an image display device according to embodiments of the present invention will be described with reference to the drawings.

  First, FIG. 1 is a diagram showing a usage pattern of a light source device and an image display device 120 having the light source device according to an embodiment of the present invention. FIG. 1A is a perspective view of the inside of the vehicle 101 from the side of the vehicle 101, and FIG. 1B is a view of the front of the traveling direction from the inside of the vehicle 101. In this embodiment, as an example, the present invention is applied to an in-vehicle head-up display using a light source device.

  As shown in FIG. 1A, the image display device 120 is installed inside the dashboard 111 of the vehicle 101. As shown in FIG. 1A and FIG. 1B, the image display device 120 applies the laser light modulated by the video signal to the projection region 113 disposed near the driver seat below the windshield 112. Project.

  The laser light is reflected by the projection area 113 and is irradiated to a horizontally long area (eye box area) around the eye position of the driver 102. Thus, the predetermined image 130 is displayed as a virtual image in the field of view ahead of the driver 102. The driver 102 can superimpose an image 130 that is a virtual image on the scenery in front of the windshield 112. That is, the image display device 120 forms an image 130 that is a virtual image in a space in front of the projection area 113 of the windshield 112.

  FIG. 2 is a schematic diagram showing an internal configuration of the image display device 120. As shown in FIG. 2, the image display device 120 includes an optical module 121 (light source device) and a virtual image optical system 122.

  Further, FIG. 3 is a schematic diagram showing an internal configuration of the optical module 121. The optical module 121 includes LD 201, LD 202, and LD 203 which are laser diodes (hereinafter referred to as LDs) as laser light sources, and emits laser light modulated by a video signal (not shown). In the present invention, the LD 201 is a blue semiconductor laser light source, the LD 202 is a green semiconductor laser light source, and the LD 203 is a red semiconductor laser light source.

  Laser light emitted from each LD is shaped as a substantially coaxial laser beam via the first dichroic mirror 210, the second dichroic mirror 211, and the third dichroic mirror 212, and is incident on the scanning unit 213. Thereafter, the laser beam is guided to the virtual image optical system 122 shown in FIG. 2 through a scanning mirror 213a and a screen driving unit 213b for three-dimensional display in the scanning unit 213.

  In FIG. 3, 204 is a first collimator module, 205 is a second collimator module, 206 is a third collimator module, 207 is a first shift module, 208 is a second shift module, and 209 is a third shift module. is there. Specific configurations of the first collimator module 204, the second collimator module 205, the third collimator module 206, the first shift module 207, the second shift module 208, and the third shift module 209 will be described later.

  Next, reference numeral 214 denotes a spectroscopic mirror that passes about 95% of the laser light from each LD and reflects about 5%. The reflected laser beam of about 5% is guided to the luminance monitor 215 ahead of the laser beam and used for luminance adjustment or the like in the image display device.

  The scanning mirror 213a has an axis that reciprocates at a resonance frequency of about 20 kHz (referred to as a high speed axis for convenience) and an axis that reciprocates at an image frame rate (60 Hz in the embodiment) (for convenience, a low speed axis). Have two rotation axes.

  Returning to FIG. 2, the virtual image optical system 122 includes a curved reflection surface 122 a and a planar reflection surface 122 b. Laser light emitted from the optical module 121 is reflected by the virtual image optical system 122 toward the windshield 112. The laser light reflected by the windshield 112 is applied to the eyes 102a of the driver 102. The optical system of the optical module 121 and the virtual image optical system 122 are set so that the virtual image 130 is displayed in a predetermined size in front of the windshield 112.

  In this embodiment, the example in the case of developing to a windshield type head-up display that observes a virtual image through a windshield has been described, but a head-up type called a combiner type that observes a virtual image through an optical component called a combiner. It can also be expanded to a display.

  In this embodiment, the scanning mirror 213a has an optical configuration using a reciprocating mirror using a so-called MEMS structure using an effect of applying distortion by a piezoelectric material, an electromagnetic force, or static electricity. As long as the laser beam is scanned, a polygon mirror or a galvanometer mirror can be used.

  Next, FIG. 4 shows the appearance of the optical module 121. In the figure, reference numeral 600 denotes a shield cover, and a projection window 600a is formed in a part thereof. Reference numeral 700 denotes a cooling unit for radiating heat generated in the optical module 121. The cooling unit 700 includes a Peltier element, a heat sink, and the like, but a detailed description thereof is omitted.

  5 is a perspective view showing an internal configuration of the optical module 121. In FIG. 5, 500 is an optical base portion on which a portion surrounded by a broken line in FIG. 3 is mounted, and 501 is a scanning portion 213. The scanning base unit 502 is a combined base unit on which the optical base unit 500 and the scanning base unit 501 are mounted. Reference numeral 500e denotes an opening formed to guide the luminance detection laser beam split by the spectral mirror 214 to the luminance monitor 215 (see FIG. 3).

  6 shows an external appearance of the collimator module, and FIG. 7 shows an exploded perspective view of the collimator module. Since the first collimator module 204, the second collimator module 205, and the third collimator module 206 have the same structure, the description will be made based on the first collimator module 204 as a representative.

  6 and 7, 301 is a focus slider, 301a is a rail abutting portion that abuts on a focus rail (see 308 and 309 in FIG. 8), 301b is a protruding portion, and 301c is a screw hole formed in the protruding portion 301b. , 301d and 301e are screw holes into which the emission angle adjusting screws 306 and 307 are inserted, 301f is an opening through which laser light from each LD passes, and 301g is a recess.

  Next, reference numeral 302 denotes a collimator holder, which has a concave portion 302a, an opening 302b through which laser light from each LD passes, and a step portion 302c for positioning the collimator lens 303. The collimator lens 303 includes the step portion 302c. Adhered and fixed to. The collimator holder 302 is accommodated in a recess 301g formed in the focus slider 301. At that time, the collimator holder 302 is pressed by the pressing portion 304a of the collimator shift spring 304 also accommodated in the recess 301g, and is deployed without rattling. The

  Reference numeral 305 denotes a metal collimator cover having an opening 305a in the center and a plurality of holding claws 305b around the collimator holder 302, which is housed in the recess 301g of the focus slider 301, and a collimator It is attached to the focus slider 301 so as to cover the shift spring 304.

  The laser light emitted from the LD is emitted in a direction connecting the light emitting point of the LD and the optical center of the collimator lens. Therefore, the emission angle of the laser beam can be adjusted by turning the emission angle adjusting screws 306 and 307, pressing the collimator holder 302 with the tip of the screw, and changing its position.

  FIG. 8 shows a state in which the first collimator module 204, the first shift module 204, and the first dichroic mirror 210 are removed from the configuration shown in FIG. As shown in the figure, the optical base portion 500 is formed with a recess 500a for mounting the first collimator module 204, and further, an elongated round adjustment hole 500b is formed on the bottom surface thereof.

  A focus rail 308 and a focus rail 309 are provided in the recess 500a. A recess and an adjustment hole are similarly formed under the second collimator module 205 and the third collimator module 206, and a focus rail is provided in the recess.

  Next, FIG. 9A and FIG. 9B are cross-sectional views showing the first collimator module 204 incorporated in the optical base unit 500. As shown in the drawing, the first collimator module 204 is attached with a screw 600 and a spring 601 through the adjustment hole 500b from a recess 500c formed on the back side of the optical base unit 500.

  The first collimator module 204 is pulled in the direction of arrow F (see FIG. 9B) by the spring 601, and the rail contact portion 301a is pressed against the focus rail 308 and the focus rail 309. Yes. Therefore, the first collimator module 204 is attached to the optical base unit 500 without rattling.

  Further, the first collimator module 204 is attached with a focus adjustment screw 602 inserted through a screw hole 500d formed on the back surface of the optical base unit 500. Since the spring 603 is disposed between the back surface of the optical base unit 500 and the first collimator module 204 and is pressed in the direction of arrow E, the first collimator module 204 is rotated by the rotation of the focus adjustment screw 602. Since it can slide on the focus rail 308 and the focus rail 309 without shaking, and the position can be adjusted in the direction of arrow D, the focus adjustment in the optical axis direction of the collimator lens 35 can be performed.

  The emission angle adjusting screws 306 and 307 are inclined 45 ° above the horizontal as shown in FIG. 9B. Therefore, as shown in FIG. 5, even if the first collimator module 204, the second collimator module 205, and the third collimator module 206 are arranged close to each other, the adjustment screws are easily turned and adjusted by a screwdriver or the like. Be able to.

  Next, FIG. 10 shows an appearance of the first shift module 207, and FIG. 11 shows an exploded perspective view of the first shift module 207. Since the first shift module 207, the second shift module 208, and the third shift module 209 have the same structure, the description will be made based on the first shift module 207 as a representative here.

  10 and 11, 401 is a rotation base, 401 a is a hole portion into which the tip end portion 420 a of the rotation shaft portion 410 is inserted, and 401 b is an extension portion having a receiving portion 401 c that receives the tip end of the angle adjusting screw 409. , 401d is a groove portion into which the fixing screws 406 and 407 enter, 401e is a bearing portion, and 401f is a screw hole to which the fixing screws 406 and 407 are attached.

  Reference numeral 402 denotes a movable table, to which a shift glass 403 made of a parallel plate is attached by a metal shift glass cover 404. Reference numeral 402a denotes an extension portion having a screw hole 402c to which the position adjusting screw 409 is attached, and 402b denotes a rotation shaft, which is placed on the bearing portion 401e of the rotation base.

  Reference numeral 408 denotes a bearing plate for attaching the movable table 402 to the rotation base 401. The bearing plate 408 has a hole 408 a for the fixing screws 406 and 407 and a bearing hole 408 b that holds the rotating shaft 402 of the movable table 402.

  As shown in FIG. 10, with the rotation shaft 402 b of the movable table 402 placed on the bearing portion 401 e of the rotation base 401, the rotation shaft 402 b of the movable table 402 is passed through the bearing hole 408 b of the bearing plate 408. The fixing screw 406 is used for fixing. Similarly, the bearing plate 408 is fixed with a fixing screw 407 on the opposite side.

  Further, on the fixed screw 406 side, the winding portion 405a of the spring member 405 is passed through the rotation shaft 402b of the movable table 402, and the hook portion 405b is hooked to the rotation base 401 side as shown in the figure, and the other hook portion. 405 c is hung on the movable table 402. As a result, the movable table 402 is urged in the direction of arrow H in FIG. 10 and does not rattle.

  Then, by turning the angle adjusting screw 409 in the arrow I direction, the movable table 402 can be rotated around the rotation shaft 402b, and the inclination of the shift glass 403 can be adjusted in the arrow G direction. Further, the optical axis of the laser beam can be adjusted by rotating the rotation base 401 with respect to the rotation shaft portion 410 as indicated by an arrow J.

  Returning to FIG. 8, the first shift module 207 is attached to the opening 500 f formed in the optical base unit 500. Although not visible in the figure, the second shift module 208 and the third shift module 209 are similarly attached to the apertures formed in the optical base unit 500.

  Next, FIG. 12 is a schematic diagram for explaining optical axis adjustment of laser light. When there is no shift glass 403 (or the plane is parallel to a plane orthogonal to the optical axis), the optical axis of the laser light is as indicated by a broken line. Here, when the movable table 402 is rotated in the direction of arrow P about the rotation axis 402b, the optical axis moves as indicated by a solid line. On the other hand, when the movable table 402 is rotated about the rotation axis 402b in the direction of the arrow Q or R, the optical axis of the laser light moves in the opposite direction.

  FIG. 13 is an external view showing a part of the back side of the optical module. The luminance monitor 215 is disposed on the same surface as the surface on which the LD 201, LD 202, and LD 203 are attached. As described above, the spectroscopic mirror 214 is configured so that about 5% of the laser light is dispersed in the direction of the arrow S and reaches the luminance monitor 215. By arranging in this way, various wirings for input and output can be connected from the same surface side, so that the wiring can be easily handled.

The configuration of the light source device and the image display device in the present embodiment has been described above. Next, the adjustment procedure of the optical module 121 will be described.
(1) Output laser light emission angle and focus coarse adjustment a. The optical module is attached to an emission angle adjusting jig (not shown).

  b. Using an autocollimator, the emission angle adjustment screw 306 and the emission angle adjustment screw 307 of the first collimator module 204 are rotated and coarsely adjusted so that the emitted laser light falls within the observation range of the monitor.

  c. The focus adjustment screw 602 of the first collimator module 204 is turned so that the spot size of the laser beam on the monitor is minimized.

d. Similarly, for the second collimator module 205 and the third collimator module 206, adjustment of the emission angle of the emitted laser light and coarse focus adjustment are performed so that the red, blue, and green color beam spots overlap each other. To do.
(2) Coarse adjustment of beam position of emitted laser light a. The optical module is attached to a beam position adjusting jig (not shown).

b. The position adjusting screw 409 of the first shift module 207 and the rotation table 401 itself are rotated to adjust the angle of the shift glass 403 so that the emitted laser light comes to a predetermined position. Similarly, with respect to the second shift module 208 and the third shift module 209, the angle of the shift glass is adjusted so that the beam spots of red, blue, and green overlap each other.
(3) Fine adjustment of focus of emitted laser beam a. The beam profiler is set to a predetermined observation distance (not shown).

b. Adjust the first collimator module 204, the second collimator module 205, and the third collimator module 206 to finely adjust the focus so that the beam width (short axis) at the position of the beam intensity 1 / e ² (13.5%) is minimized. To do.

  c. The shift glasses of the first shift module 207, the second shift module 208, and the third shift module 209 are moved and adjusted so that the beam of the emitted laser light comes to the center of the scanning mirror 213a (beam position correction).

  In this way, each adjustment is completed. In the above procedure, the description of the adjustment in the scanning unit 213 is omitted.

  FIG. 14A is a diagram plotting the condensing positions of red light, green light, and blue light when the conventional configuration is adopted and optical adjustment is performed, and FIG. 14B is a diagram illustrating the present embodiment. The condensing positions of red light, green light, and blue light with respect to the optical axis direction when the configuration described in the embodiment is adopted and optical adjustment is performed are shown. The conventional configuration mentioned here is a case where a laser diode and a collimator lens are first module-unitized and then mounted on an optical module.

  As shown in FIG. 14 (a), the condensing position of the laser light emitted from the optical module is substantially the same for green light and red light, but for blue light, it is retracted by about 1 cm. Furthermore, it can be seen that there is also a variation in the light beam diameter at the condensing position and the focus position between the optical modules.

  On the other hand, as shown in FIG. 14B, when the adjustment mechanism in the present embodiment is adopted, the condensing position of each color light is approximately the same position, and the light beam diameter is approximately 50 to 70 micrometers. It was in time, and individual variations between optical modules could be reduced.

  As a result of the above, it has been possible to eliminate the phenomenon that the displayed video appears blurred only by a specific color due to a blur or a focus position shift for each color.

  The configuration described in the above embodiment is merely an example, and it is needless to say that the configuration other than the modes illustrated in the description and the drawings can be appropriately described.

  The present invention enables various optical adjustments of a light source device using a laser light source, and is applicable to an image display device using the light source device.

DESCRIPTION OF SYMBOLS 120 ... Image display apparatus 121 ... Optical module (light source device)
122 ... Virtual image optical system 201 ... LD (blue laser diode)
202 ... LD (green laser diode)
203 ... LD (red laser diode)
204 ... 1st collimator module 205 ... 2nd collimator module 206 ... 3rd collimator module 207 ... 1st shift module 208 ... 2nd shift module 209 ... 3rd shift module 210 ... 1st dichroic mirror 211 ... 2nd dichroic mirror 212 ... Third dichroic mirror 214 ... Spectroscopic mirror 215 ... Luminance monitor 303 ... Collimator lens 306 ... Emission angle adjustment screw 307 ... Emission angle adjustment screw 308 ... Focus rail 309 ... Focus rail 401 ... Rotation base 402 ... Movable table 403 ... Shift glass 409 ... Angle adjustment screw 410 ... Rotating shaft 602 ... Focus adjustment screw

Claims (6)

A laser light source for emitting laser light;
A first adjustment mechanism that receives the laser light from the laser light source and adjusts the emission angle and focus of the laser light;
A second adjustment mechanism that adjusts the position of the incident laser beam, upon which the laser beam from the first adjustment mechanism is incident;
A light source device comprising: a mirror that receives laser light from the second adjustment mechanism and emits the incident laser light in a predetermined direction. The light source device according to claim 1,
The first adjustment mechanism includes a collimator lens and an adjustment mechanism that changes an optical center of the collimator lens. The light source device according to claim 1,
The second adjustment mechanism includes a parallel plate that transmits the laser light, an adjustment mechanism that changes an inclination of the parallel plate, and an adjustment mechanism that rotates the parallel plate. The light source device according to claim 1,
The laser light source includes a first laser light source that emits red laser light, a second laser light source that emits blue laser light, and a third laser light source that emits green laser light. A light source device. The light source device according to claim 4,
A light source device comprising the first adjustment mechanism and the second adjustment mechanism for each of the first laser light source, the second laser light source, and the third laser light source.   An image display device comprising the light source device according to claim 1.