JP2011154324A - Image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display apparatus capable of properly correcting an image drawing position when vibration is added. <P>SOLUTION: In the image display apparatus 1, an infrared laser LD4 is installed in a laser light source unit 9. Also, a photodetector 12 for receiving the laser beam of the infrared laser LD4 is installed on the outside of the image drawing region V of a screen 11. Thus, drawing timing of an image is corrected using the output signal of the photodetector 12 as a reference. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image display device that displays an image by projecting light emitted from a light source such as a projector or a head-up display onto a screen or the like.

  An image display device such as a projector or a head-up display has an image display unit such as a screen for displaying an image, two or more types of laser light sources such as red, blue, and green as light sources, and laser light emitted from the laser light source. And a main body having drawing means such as a MEMS (Micro Electro Mechanical Systems) mirror that scans the display and draws an image.

  When this type of image display device is mounted on a vehicle such as an automobile, the image drawn on the screen vibrates up and down due to vibrations that occur while the vehicle is running, which makes it difficult to see or cause motion sickness. There was a problem of having pleasure.

  For such a problem, for example, a video information display system described in Patent Document 1 has been proposed. The video information display system described in Patent Literature 1 includes a vibration sensor, and suppresses blurring of irradiation video information irradiated on a screen based on a signal from the vibration sensor.

JP-A-11-161216

  However, if the vibration is suppressed by the vibration sensor as in the video display system described in Patent Document 1, for example, even when vibration is applied but the relative position between the main body and the screen is not shifted, the vibration is suppressed by the detected vibration. Therefore, the image displayed on the screen may be shifted.

  In addition, even when vibration is applied to the main body, when moving in parallel in the vertical direction and when the irradiation angle to the screen moves, the latter has a larger amount of image movement on the screen, but with one vibration sensor, In order to distinguish one of them, it is necessary to provide a plurality of vibration sensors. Therefore, there is a problem that costs increase due to an increase in the number of parts and complicated control.

  Therefore, an object of the present invention is to provide an image display device that can appropriately correct the drawing position of an image when vibration is applied, for example.

In order to solve the above problem, an image display device according to claim 1 includes an image display unit on which an image is displayed, a plurality of first laser light sources that form the image, and the first laser light source. A second laser light source that emits a laser beam having a wavelength other than visible light in an image display device comprising:
Reflecting means for reflecting the laser light emitted from the second laser light source toward the image display unit, and a laser provided outside the image display area of the image display unit and emitted from the second laser light source A light receiving element that receives light, and a correction unit that corrects a position of the image drawn on the image display unit based on a signal received by the light receiving element are provided.

1 is a block diagram of an image display apparatus according to a first embodiment of the present invention. It is the block diagram which showed the laser light source unit and screen of the image display apparatus shown by FIG. It is explanatory drawing which showed the relationship between the image drawing area | region and light receiving element, and scanning locus | trajectory in a normal screen. FIG. 4 is a waveform diagram in the case of FIG. 3. It is explanatory drawing which showed the case where an image drawing area | region moved below by vibration. FIG. 6 is a waveform diagram in the case of FIG. 5. It is explanatory drawing which showed the correction | amendment of FIG. It is explanatory drawing which showed the case where an image drawing area | region moved to the right direction by vibration. FIG. 9 is a waveform diagram in the case of FIG. 8. It is explanatory drawing which showed the correction | amendment of FIG. It is explanatory drawing of correction | amendment operation | movement in the case of moving to right direction largely. FIG. 12 is a waveform diagram of the MEMS mirror driving current and the output waveform of the light receiving element in the case of FIG. 11. It is the block diagram which showed the laser light source unit and screen at the time of using a laser light source of 2 wavelengths. It is explanatory drawing which showed the relationship between the image drawing area | region and light receiving element, and a scanning locus | trajectory in the image forming apparatus shown in FIG. It is a block diagram of the image display apparatus concerning 2nd Example of this invention. FIG. 16 is a configuration diagram illustrating a laser light source unit and a screen of the image display device illustrated in FIG. 15. It is a block diagram of the image display apparatus concerning the 3rd Example of the present invention. It is the block diagram which showed the laser light source unit and screen of the image display apparatus shown by FIG. It is explanatory drawing which showed the structure of the 4-part dividing light receiving element.

  Hereinafter, an image display apparatus according to an embodiment of the present invention will be described. An image display device according to an embodiment of the present invention reflects a laser beam having a wavelength other than visible light emitted from a second laser light source toward an image display unit by a reflection unit, and displays an image on the image display unit. The laser beam emitted from the second laser light source is received by the light receiving element provided outside the region, and the position of the image drawn on the image display unit is corrected by the correcting means based on the signal received by the light receiving element. Therefore, in order to perform correction based on the positional relationship on the laser light source side with respect to the image display unit detected by the light receiving element, if the relative position does not deviate, the correction is not performed. Even when the image moves small due to parallel movement in the vertical direction or when the image moves largely due to movement of the irradiation angle, the drawing position of the image can be corrected appropriately.

  The drawing unit may also serve as the reflecting unit. By doing so, there is no need to provide a separate reflecting means, and the image display device can be downsized.

  Further, the correction means may correct the image drawing timing with reference to the signal received by the light receiving element. By doing so, the vibration is corrected electrically, so that only the second laser light source and the light receiving element are added, and it is not necessary to add a mechanical member, and the vibration is corrected at low cost. be able to.

  The signal received by the light receiving element is a pulse signal that rises when the light receiving element receives the laser beam and falls when the laser beam stops receiving the laser beam. The pulse signal falls and the drawing means is driven. The image drawing timing may be corrected based on the signal. In this way, even when the image is greatly shifted in the left-right direction, correction can be made reliably, and the area outside the display area of the image display unit can be reduced and the image display area can be increased. In addition, the light receiving element can be reduced in size.

  The image forming apparatus further includes a drawing direction changing unit that changes a drawing direction of the drawing unit, and the correction unit changes the drawing direction of the drawing direction changing unit based on the signal received by the light receiving element to correct the drawing position of the image. Also good. In this way, since the correction can be made mechanically, it is not necessary to change the drawing timing control and the like, and changes in the circuit and software can be reduced.

  Further, a reflection direction changing means for changing the reflection direction of the reflection means is provided, and the reflection direction changing means receives the laser beam of the second laser light source at the center of the light receiving element based on the signal received by the light receiving element. The reflection direction of the reflection unit may be changed, and the correction unit may correct the position of the image drawn on the image display unit based on the signal received by the light receiving element. By doing so, control is performed so that the laser beam of the second laser light source is always received at the center of the light receiving element, and correction is performed based on the control. It is also possible to cope with a case where the relative position on the laser light source side with respect to the light receiving element greatly deviates in a short time due to a strong impact.

  The reflection direction changing unit may also change the drawing direction of the drawing unit. By doing in this way, a drawing means can also be controlled according to control of a reflection direction change means, and both control can be performed by one mechanism.

  In addition, one of the first laser light sources may include a laser light source that emits two-wavelength laser light including the second laser light source. By doing so, the number of laser light sources can be reduced, so that the image display device can be miniaturized.

  An image display apparatus 1 according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the image display device 1 includes an image signal input unit 2, a video ASIC 3, a frame memory 4, a ROM 5, a RAM 6, a laser driver ASIC 7, a MEMS control unit 8, and a laser light source unit 9. , A screen ASIC 3, and a video ASIC 3, a frame memory 4, a ROM 5, a RAM 6, a laser driver ASIC 7, a MEMS control unit 8, and a laser light source unit 9 are housed in a single housing as a main body. Are mounted in the vehicle cabin.

  The image signal input unit 2 receives an image signal input from the outside and outputs it to the video ASIC 3.

  The video ASIC 3 as correction means is a block that controls the laser driver ASIC 7 and the MEMS control unit 8 based on the image signal input from the image signal input unit 2 and the scanning position information input from the laser light source unit 9. (Application Specific Integrated Circuit). The video ASIC 3 includes a synchronization / image separation unit 31, a bit data conversion unit 32, a light emission pattern conversion unit 33, and a timing controller 34. In this embodiment, a light reception signal from a light receiving element 12 described later is also input.

  The synchronization / image separation unit 31 separates the image data displayed on the screen 11 serving as the image display unit and the synchronization signal from the image signal input from the image signal input unit 2 and writes the image data in the frame memory 4. The synchronization signal is output to the timing controller 34.

  The bit data converter 32 reads the image data written in the frame memory 4 and converts it into bit data.

  The light emission pattern conversion unit 33 converts the bit data converted by the bit data conversion unit 32 into signals representing the light emission patterns of a red laser LD1, a green laser LD2, and a blue laser LD3, which will be described later. Further, the light emission pattern conversion unit generates a signal representing the light emission pattern of the infrared laser LD4 based on later-described scanning position information (for example, information such as the angle of the MEMS mirror 98).

  The timing controller 34 controls the operation timing of the synchronization / image separation unit 31 and the bit data conversion unit 32 based on the synchronization signal input from the synchronization / image separation unit 31 and the light reception signal from the light receiving element 12. The timing controller 34 also controls the operation timing of the MEMS control unit 8 described later. That is, the timing controller 34 controls the vibration correction in this embodiment.

  In the frame memory 4, the image data separated by the synchronization / image separation unit 31 is written. The ROM 5 stores a control program and data for operating the video ASIC 3. The RAM 6 sequentially reads and writes various data as a work memory when the video AISC 3 operates.

  The laser driver ASIC 7 is a block that generates a signal for driving a laser diode provided in a laser light source unit 9 described later, and is configured as an ASIC (Application Specific Integrated Circuit). The laser driver ASIC 7 includes a red laser driving circuit 71, a green laser driving circuit 72, a blue laser driving circuit 73, and an infrared laser driving circuit 74.

  The red laser driving circuit 71 drives the red laser LD1 based on the signal output from the light emission pattern conversion unit 33. The green laser driving circuit 72 drives the green laser LD2 based on the signal output from the light emission pattern conversion unit 33. The blue laser drive circuit 73 drives the blue laser LD3 based on the signal output from the light emission pattern conversion unit 33.

  The infrared laser driving circuit 74 drives the infrared laser LD4 based on the signal output from the light emission pattern conversion unit 33.

  The MEMS control unit 8 controls a MEMS mirror 98 described later in the laser light source unit 9 based on a signal output from the timing controller 34. The MEMS control unit 8 includes a servo circuit 81 and a driver circuit 82.

  The servo circuit 81 controls the operation of the MEMS mirror 98 based on the signal from the timing controller 34.

  The driver circuit 82 amplifies the control signal of the MEMS mirror 98 output from the servo circuit 81 to a predetermined level and outputs the amplified signal.

  As shown in FIG. 2, the laser light source unit 9 includes a red laser LD1, a green laser LD2, a blue laser LD3, an infrared laser LD4, collimator lenses 91, 92, 93, 94, and a wavelength selective element 95. A polarizing beam splitter 96, a quarter-wave plate 97, and a MEMS mirror 98.

  The red laser LD1 as the first laser light source emits red laser light. The green laser LD2 as the first laser light source emits green laser light. The blue laser LD3 as the first laser light source emits blue laser light.

  The infrared laser LD4 as the second laser light source emits infrared laser light having a wavelength other than visible light.

  The collimator lens 91 converts the laser light incident from the red laser LD1 into parallel light and emits it to the wavelength selective element 95. The collimator lens 92 converts the laser light incident from the green laser LD2 into parallel light and emits it to the wavelength selective element 95. The collimator lens 93 converts the laser light incident from the blue laser LD3 into parallel light and emits it to the wavelength selective element 95. The collimator lens 94 converts the laser light incident from the infrared laser LD4 into parallel light and emits it to the wavelength selective element 95.

  The wavelength selective element 95 reflects the laser light emitted from the red laser LD1 toward the polarization beam splitter 96 by the reflection surface 95a, and reflects the laser light emitted from the green laser LD2 to the polarization beam splitter 96 by the reflection surface 95b. The laser beam emitted from the blue laser LD3 is reflected by the reflecting surface 95c toward the polarization beam splitter 96, and the laser beam emitted from the infrared laser LD4 is transmitted. By doing in this way, the emitted light from each laser is superimposed.

  The polarizing beam splitter 96 reflects the laser beam emitted from the wavelength selective element 95 toward the quarter-wave plate 97.

  The quarter-wave plate 97 transmits the laser beam reflected by the deflection beam splitter 96, and the transmitted laser beam is directed to the MEMS mirror 98.

  The MEMS mirror 98 as a drawing unit reflects the laser light transmitted through the quarter wavelength plate 97 toward the screen 11. Further, in order to display an image input to the image signal input unit 2, it is movable so as to scan the screen 11 under the control of the MEMS control unit 8, and scanning position information at that time (for example, an angle of the MEMS mirror 98, etc.) Is output to the video ASIC 3.

  The screen 11 serving as an image display unit displays (draws) an image emitted from the laser light source unit 9. Further, the screen 11 has an image drawing area V in the approximate center, and a light receiving element 12 is provided outside the image drawing area V, that is, on the outer periphery of the screen 11.

  The light receiving element 12 is an element that receives laser light emitted from the infrared laser LD4, and is configured by an element that can receive infrared light. Further, the light receiving element 12 may be provided at an arbitrary position on the screen 11 as long as it is an area outside the image drawing area V (an area to be overscanned) within a range scanned by the laser light source unit 9. In FIG. 2, it is arranged at the upper right of the screen as an example.

  Next, the vibration correction operation in the image display apparatus 1 having the above-described configuration will be described with reference to FIGS.

  First, the case where vibration is not applied is shown in FIGS. FIG. 3 shows the relationship between the image drawing region V on the screen 11 and the light receiving element 12 and the scanning locus S of the laser light source unit 9 (MEMS mirror 98). FIG. 4 shows the drive current of the MEMS mirror 98 in the horizontal direction in the case of FIG. 3, the drive current (solid line) and angle information (dotted line) of the MEMS mirror 98 in the vertical direction, the light receiving element output, the signal indicating the drawing area, infrared It is the wave form diagram which displayed the signal which shows ON / OFF of a laser.

  If the point A in the figure is the scanning start point, the scanning trajectory S is scanned from left to right for a predetermined number of scanning lines and drawn for one frame, from the last line at the bottom to the point A. It also shows that the operation of returning and scanning the next frame is repeated.

  In FIG. 4, the drive current of the MEMS mirror 98 in the left-right direction in the case of FIG. 3 is a sine wave with a constant frequency. Here, when the drive current of the MEMS mirror 98 in the left-right direction is positive current, it is scanned to the right side, and when it is negative current, it is scanned to the left side. In addition, the drive current of the MEMS mirror 98 in the vertical direction becomes a negative current after the point A and becomes a positive current before the point A. When the current is negative, an image is drawn and the angle information is gradually drawn. Is downward, and in the case of positive current, the angle information is upward because it returns to the point A from the lowermost end.

  The output of the light receiving element 12 is a pulse signal that occurs when the scanning trajectory S passes through the light receiving element 12, that is, a pulse signal that rises when laser light is received and falls when no laser light is received. In the case of 3, when the point A is used as a reference, the second wave and the third wave are generated at the maximum value (top of the mountain) of the sine wave of the drive current of the MEMS mirror 98 in the left and right directions. That is, at this time, the scanning locus S passes through the light receiving element 12. The signal indicating the drawing area indicates a range in which an image is drawn (lighting regions of the red laser LD1, the green laser LD2, and the blue laser LD3 that are the image drawing regions V). The signal indicating the drawing area is generated t2 hours after the fall of the output pulse of the light receiving element 12. This t2 is a value determined in advance from the position and size of the light receiving element 12 and the speed (refresh rate) of the scanning locus S.

  A signal indicating ON / OFF of the infrared laser LD4 is turned ON on the plus side (peak side) in the sine wave of the drive current of the MEMS mirror 98 in the left-right direction. That is, it is turned on in the right overscan region where the light receiving element 12 of the screen 11 is provided. This operation is performed by the video ASIC 3. Note that since the infrared laser LD4 is not visible light, scanning with the image display region V lit along the scanning trajectory S has almost no effect on the image.

  Here, FIGS. 5 to 7 show cases where the image drawing region V is shifted downward due to vibration or the like. FIG. 5 shows a case where the line is shifted downward by one line with respect to FIG. In this case, the output of the light receiving element 12 is generated from the maximum value in the sine wave of the drive current of the MEMS mirror 98 in the left-right direction of the first wave when A is a reference. The waveform in this state is shown in FIG. Before the drawing area correction, the drawing is started at the same timing as that in FIG. 4 before the correction, and after the drawing area correction, the drawing is started at the corrected timing. A signal indicating ON / OFF of the infrared laser LD4 is omitted.

  The signal indicating the drawing area is normally generated immediately after the output pulse of the first light receiving element 12 as shown in FIG. That is, the image is drawn immediately after the output pulse of the first light receiving element 12. Therefore, in the case of FIG. 5 as well, correction is performed so that an image is drawn immediately after the output pulse of the first light receiving element 12 is generated (red laser LD1, green laser LD2, and blue laser LD3 are driven). As shown in FIG. 4, it is possible to eliminate the deviation of the position of the image drawing area V on the screen 11 from the normal case. That is, it is possible to always draw at the same position on the screen 11. That is, the image drawing timing is corrected based on the signal received by the light receiving element 12.

  Next, the case where the image drawing area V is shifted rightward due to vibration or the like is shown in FIGS. In this case, since the time during which the scanning locus S passes through the region of the light receiving element 12 becomes longer, the width of the output pulse of the light receiving element 12 becomes wider. The waveform in this state is shown in FIG. Before the drawing area correction, the drawing is started at the same timing as that in FIG. 4 before the correction, and after the drawing area correction, the drawing is started at the corrected timing. A signal indicating ON / OFF of the infrared laser LD4 is omitted.

  The signal indicating the drawing area is generated t2 hours after the fall of the output pulse of the light receiving element 12, as shown in FIG. When the width of the output signal of the light receiving element 12 becomes wider, it becomes less than t2 from the fall of the output pulse of the light receiving element 12, so that the signal indicating the drawing area is shifted so as to be t2, that is, the image drawing timing is shifted. By correcting in this way, the position of the image drawing area V on the screen 11 can be prevented from deviating from the normal case, as shown in FIG.

  The same applies to the case of shifting to the left direction. When shifting to the left direction, the width of the output pulse of the light receiving element 12 becomes narrow, but the signal indicating the drawing area is sent to the falling edge of the output pulse of the light receiving element 12. From t to t2, the position of the image drawing area V on the screen 11 can be prevented from deviating from the normal case.

  Further, if the amount of image drawing area V is shifted to the right due to vibration or the like, the scanning locus S exceeds the light receiving element 12 as shown in FIG. 11, and therefore the output pulse of the light receiving element 12 as shown in FIG. The center of is once recessed. Since the normal falling f of the output pulse of the light receiving element 12 is always generated after the maximum value in the sine wave of the drive current of the MEMS mirror 98 in the left-right direction, in the sine wave of the drive current of the MEMS mirror 98 in the right direction. By detecting the falling f of the output pulse of the light receiving element 12 that occurs after detection of the maximum value m, it is possible to correct correctly. This is the same even when the light receiving element is provided on the left side of the screen 11 and the amount shifted in the left direction is large. That is, the image drawing timing is corrected based on the falling edge f of the pulse signal and the drive signal of the drawing means.

  According to this embodiment, in the image display device 1, the infrared laser LD 4 is provided in the laser light source unit 9, and the light receiving element 12 that receives the laser light of the infrared laser LD 4 is provided outside the image drawing region V of the screen 11. Since the image drawing timing is corrected based on the output signal of the light receiving element 12, the image can be always drawn at the same position on the screen 11. When the image is added, the drawing position of the image is appropriately corrected even when the image moves small due to the relative position moving parallel in the vertical direction or even when the image moves largely due to the movement of the irradiation angle. be able to.

  Further, since the correction for vibration is performed electrically, the vibration correction can be performed at low cost by adding only the infrared laser LD4 and the light receiving element 12 and without adding a mechanical member.

  In addition, since the image drawing timing is corrected by detecting the falling f of the output signal of the light receiving element after the detection of the maximum value m of the MEMS mirror driving current in the left-right direction, even when the image is greatly shifted in the right direction. Correction can be performed reliably, and the area outside the display area of the image display unit can be reduced to increase the image display area. In addition, the light receiving element can be reduced in size.

  In the embodiment described above, one light receiving element 12 is provided, but a plurality of light receiving elements 12 may be provided. For example, in the case of FIG. 2, it is provided at the upper right of the screen 11, but if it is also provided at the lower left that is point-symmetric with respect to the center of the screen 11, vibration correction can be performed twice within one frame. Therefore, the detection accuracy can be further improved. The position of the light receiving element 12 may be an arbitrary position as long as it is an over-scanned outer peripheral area outside the image drawing area V of the screen. Correction may be made from the beginning of the frame.

  In the above-described embodiment, the infrared laser LD4 is provided independently. However, any one of the red laser LD1, the green laser LD2, and the blue laser LD3 may be a two-wavelength laser capable of emitting infrared laser light. . In this case, as shown in FIG. 13 and FIG. 14, the infrared laser light (two-dot chain line in FIG. 13) of the two-wavelength laser LD5 is compared to the other three colors of laser light (one-dot chain line in FIG. 13). The emission position is slightly shifted. Therefore, the scanning locus S is also shifted to S ′. However, if the deviation is known in advance, the correction may be performed in consideration of the deviation, and the above-described method can be applied. In other words, the timing when there is no previously known vibration is used as a reference, and if it deviates from that reference, it may be corrected to match that reference.

  Next, an image display apparatus 1 according to a second embodiment of the present invention will be described with reference to FIGS. 15 and 16. The same parts as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

  This embodiment is different from the first embodiment in that a galvano control circuit 83 is added to the MEMS controller 8 as shown in FIG. 15, and a galvano mechanism 99 is added as shown in FIG.

  The galvano mechanism 99 as the drawing direction changing means is a mechanism that mechanically changes the angle (drawing direction) of the MEMS mirror 98 to correct the image drawing region V, and is controlled by the galvano control circuit 83. The galvano control circuit 83 is controlled by a control signal from the timing controller 34 based on the output signal of the light receiving element 12. Therefore, the galvano mechanism 99 is corrected by the output signal of the light receiving element 12. The image drawing operation (scanning operation) of the MEMS mirror 98 is controlled from the driver circuit 82 as in the first embodiment. That is, the galvano mechanism 99 performs only the correction operation at the time of vibration detection independently of the image drawing operation.

  In the first embodiment, the image drawing timing is changed based on the output signal of the light receiving element 12. However, in this embodiment, the image drawing area V is drawn based on the output signal of the light receiving element 12. Correct the direction. For example, as shown in FIG. 5, when the galvano mechanism 99 is shifted down by one line, the angle of the MEMS mirror 98 is changed so that the galvano mechanism 99 is shifted up by one line, so that the drawing can always be performed at the same position on the screen 11. That is, the drawing position of the image is corrected by changing the drawing direction of the galvano mechanism 99 based on the signal received by the light receiving element 12.

  According to the present embodiment, since the position of the image drawing region V is corrected by the galvano mechanism 99 based on the output signal of the light receiving element 12, it can be corrected mechanically, so that the drawing control and the like are changed. There is no need to change the circuit and software.

  Next, an image display apparatus 1 according to a third embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first and second embodiments described above are denoted by the same reference numerals and description thereof is omitted.

  In this embodiment, an error signal generation circuit 101 is added as shown in FIG. 17, the light receiving element 12 is changed to a light receiving element 12 ′, and an infrared ray is added to the laser light source unit 9 as shown in FIG. Mirror 100 is added, and the polarization beam splitter 96 is changed to a polarization beam splitter 96 ′ that transmits only the laser beam from the infrared laser LD 4 to the infrared mirror 100, and the galvano mechanism 99 as the reflection direction changing means is a MEMS. The difference from the second embodiment is that the angle (drawing direction) of both the mirror 98 and the infrared mirror 100 is changed.

  As shown in FIG. 19, the light receiving element 12 'is divided into four parts A, B, C, and D, and outputs a signal corresponding to the amount of light received by each part. The error signal generation circuit 101 generates vertical and horizontal error signals from the four output signals of the light receiving element 12 ′ and outputs them to the galvano control circuit 83.

  The infrared mirror 100 reflects the laser light emitted from the infrared laser LD 4 toward the light receiving element 12 ′ of the screen 11.

  In the present embodiment, the laser light emitted from the infrared laser LD4 is normally reflected toward the center of the light receiving element 12 ′ by the infrared mirror 100. Therefore, in the state where no vibration is applied, light is equally applied to the respective light receiving areas A, B, C, and D, and the error signal generation circuit 101 does not generate error signals in the vertical and horizontal directions. However, when the vibration is applied, the error signal generation circuit 101 generates an error signal in the vertical direction or the horizontal direction because the laser beam is biased toward any one of the light receiving areas A, B, C, and D. The galvano control circuit 83 operates the galvano mechanism 99 in a direction to cancel the error signal to change the angle of the infrared mirror 100. That is, the light receiving element 12 ′, the error signal generation circuit 101, and the galvano control circuit 83 form a feedback loop to perform servo control. Therefore, in this embodiment, the MEMS control unit 8 functions as a correction unit. The galvano mechanism 99 corrects the image drawing region V by operating the angle of the MEMS mirror 98 in the same manner as the infrared mirror 100. That is, the galvano mechanism 99 changes the reflection direction of the infrared mirror 100 and the MEMS mirror 98 so that the laser beam of the infrared laser LD4 is received at the center of the light receiving element 12 based on the signal received by the light receiving element 12. The MEMS control unit 8 corrects the position of the image drawn on the screen 11 based on the signal received by the light receiving element 12.

  According to the present embodiment, the light receiving element 12 is made into a four-divided light receiving element 12 ', the infrared mirror 100 is provided, and the galvano mechanism 99 is centered on the light receiving element 12' based on the output signal of the light receiving element 12 '. Since the MEMS mirror 98 is also operated in the same way as the infrared mirror 100 during the servo control, the correction can always be performed instead of in units of frames, so that even a vibration with a high frequency can be obtained. It is also possible to cope with the case where the relative position on the laser light source side with respect to the light receiving element 12 ′ is greatly shifted in a short time due to a strong impact.

  In particular, when the galvano mechanism 99 is used, the correction range can be made large, so that the screen is not limited to vibration caused by traveling of the vehicle, for example, when the occupant touches the screen 11 or the angle is changed. Can also be displayed.

  According to the embodiment described above, the following image display device 1 is obtained.

(Supplementary note) Screen 11 on which an image is displayed, a plurality of red laser LD1, green laser LD2, and blue laser LD3 that form an image, and laser light emitted from red laser LD1, green laser LD2, and blue laser LD3 are screened An image display device 1 having a MEMS mirror 98 that draws an image by scanning
An infrared laser LD4 that emits laser light having a wavelength other than visible light;
A MEMS mirror 98 that reflects the laser light emitted from the infrared laser LD4 toward the screen 11,
A light receiving element 12 provided outside the image display area V of the screen 11 and receiving a laser beam emitted from the infrared laser LD4;
A video ASIC 3 for correcting the position of an image drawn on the screen 11 based on a signal received by the light receiving element 12;
The image display apparatus 1 characterized by the above-mentioned.

  According to this image display device 1, correction is performed based on the positional relationship on the red laser LD1, green laser LD2, and blue laser LD3 side with respect to the screen 11 detected by the light receiving element 12. Even when the vibration is applied, even if the image moves small due to the relative position moving parallel in the vertical direction, or even when the image moves largely due to the movement of the irradiation angle, the image is drawn appropriately. The position can be corrected.

  In addition, the Example mentioned above only showed the typical form of this invention, and this invention is not limited to an Example. That is, various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Image display apparatus 3 Video ASIC (correction means)
8 MEMS control unit (correction means)
11 Screen (image display part)
12 light receiving element 12 'light receiving element 98 MEMS mirror (drawing means, reflecting means)
99 Galvano mechanism (drawing direction changing means, reflection direction changing means)
100 Infrared mirror (reflection means)
LD1 Red laser (first laser light source)
LD2 Green laser (first laser light source)
LD3 Blue laser (first laser light source)
LD4 infrared laser (second laser light source)
LD5 2 wavelength laser (laser light source that emits laser light of 2 wavelengths)

Claims (8)

An image display unit that displays an image, a plurality of first laser light sources that form the image, and a laser beam emitted from the first laser light source scans the image display unit to draw the image. In an image display device comprising a drawing means,
A second laser light source that emits laser light having a wavelength other than visible light;
Reflecting means for reflecting the laser light emitted from the second laser light source toward the image display unit;
A light receiving element that is provided outside the image display area of the image display unit and receives the laser light emitted from the second laser light source;
Correction means for correcting the position of the image drawn on the image display unit based on a signal received by the light receiving element;
An image display device comprising:   The image display apparatus according to claim 1, wherein the drawing unit also serves as the reflection unit.   The image display apparatus according to claim 1, wherein the correction unit corrects the drawing timing of the image with reference to a signal received by the light receiving element. The signal received by the light receiving element is a pulse signal that rises when the light receiving element receives laser light and falls when the laser light is no longer received.
The image display apparatus according to claim 3, wherein the correction unit corrects the drawing timing of the image based on a fall of the pulse signal and a driving signal of the drawing unit. A drawing direction changing means for changing a drawing direction of the drawing means;
3. The image according to claim 1, wherein the correction unit corrects a drawing position of the image by changing a drawing direction of the drawing direction changing unit based on a signal received by the light receiving element. Display device. A reflection direction changing means for changing the reflection direction of the reflection means;
The reflection direction changing means changes the reflection direction of the reflection means so that the laser beam of the second laser light source is received at the center of the light receiving element based on a signal received by the light receiving element,
The image display apparatus according to claim 1, wherein the correction unit corrects a position of the image drawn on the image display unit based on a signal received by the light receiving element.   The image display apparatus according to claim 6, wherein the reflection direction changing unit also changes a drawing direction of the drawing unit.   8. One of the first laser light sources is constituted by a laser light source that emits laser light having two wavelengths including the second laser light source. The image display device according to item.

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