JP5731660B2 - Projection apparatus, control method, and program - Google Patents

Description

  The present invention relates to a technical field for correcting an optical axis shift of laser light.

  A technique for detecting a deviation of the optical axis of each color light source used for drawing an image is known. For example, in Patent Document 1, in an image drawing apparatus having a plurality of light sources, the first light source is turned on and off and the second light source is turned on and off, and the first light source in the light receiving region of the light receiver is controlled. A technique for detecting a deviation between the optical axis of the first light source and the optical axis of the second light source is proposed based on the reception timing of the light and the reception timing of the second light in the light receiving region of the light receiver. Yes.

JP 2010-20087

  When detecting the optical axis deviation, if the entire scanning area is scanned every frame as in the case of normal image drawing, the speed at which the laser beam passes over the light receiving element is high. Is required.

  Examples of the problem to be solved by the present invention are as described above. The main object of the present invention is to provide an optical axis deviation correction apparatus, a control method, and a head-up display capable of detecting and correcting an optical axis deviation without requiring high detection accuracy of a light receiving element. And

According to the first aspect of the present invention, there is provided a projection device that projects an image, and a first beam emitted from a first light source and a second beam emitted from a second light source are applied to a scanning region at a predetermined frame rate. Scanning means for scanning along a scanning line, a light receiving element disposed at a position capable of receiving the first beam and the second beam scanned on the scanning region, the first beam and the second beam Control means for changing the position irradiated in the scanning region in the main scanning direction or the sub-scanning direction for each frame period with respect to the scanning region, and the timing at which the light receiving element receives the first beam; Based on the difference detected with the timing at which the second beam is received, detection means for detecting a deviation of the optical axes of the first beam and the second beam, and based on the deviation detected by the detection means Correction means for correcting an optical axis shift of the first beam or the second beam, and the control means causes the first beam and the second beam to enter the scanning region in the period of the one frame. The irradiation position is set to a plurality of continuous scanning lines in the scanning region, and the irradiation position is changed in the sub-scanning direction every period of the one frame.

The invention according to claim 7 is a projection device for projecting an image, wherein the first beam emitted from the first light source and the second beam emitted from the second light source are applied to the scanning region at a predetermined frame rate. Scanning means for scanning along a scanning line, a light receiving element disposed at a position capable of receiving the first beam and the second beam scanned on the scanning region, the first beam and the second beam The control means for drawing a predetermined pattern on the scanning area and changing the drawing position of the pattern in the main scanning direction or the sub-scanning direction every one frame period, and the light receiving element is the first beam Detecting means for detecting a deviation of the optical axes of the first beam and the second beam according to the difference between the timing of receiving the light beam and the timing of receiving the second beam, and Correction means for correcting an optical axis deviation of the first beam or the second beam based on the detected deviation, and the control means includes the first beam and the second beam during the one frame period. The pattern drawn by the beam is constituted by a plurality of continuous scanning lines in the scanning region, and the drawing position of the pattern is changed in the sub-scanning direction every period of the one frame.

In the invention according to claim 8, scanning the second beam emitted from the first beam and the second light source is irradiated from the first light source to scan along the scan lines to the scanning area at a predetermined frame rate A control method executed by a projection apparatus that projects an image , comprising: a means; and a light receiving element disposed at a position capable of receiving the first beam and the second beam scanned in the scanning region, A control step of changing a position at which the first beam and the second beam are irradiated in the scanning region in the main scanning direction or the sub-scanning direction with respect to the scanning region every one frame period; and A detecting step for detecting a shift of an optical axis between the first beam and the second beam according to a difference between a timing at which the first beam is received and a timing at which the second beam is received; And a correction step of correcting an optical axis shift of the first beam or the second beam based on the shift detected by the first beam, and the control step includes the first beam and the second beam during the one frame period. The position at which the two beams are irradiated onto the scanning area is set to a plurality of continuous scanning lines in the scanning area, and the irradiation position is changed in the sub-scanning direction every period of the one frame. And

In a ninth aspect of the present invention, a head having a light axis deviation correcting device for correcting an optical axis deviation between the first beam emitted from the first light source and the second beam emitted from the second light source. An up-display, wherein the first beam and the second beam are scanned along a scanning line with respect to a scanning region at a predetermined frame rate, and the first beam and the scanning beam scanned on the scanning region A light-receiving element disposed at a position where the second beam can be received, and a position at which the first beam and the second beam are irradiated in the scanning region are subjected to main scanning for each frame period with respect to the scanning region. Depending on the difference between the control means for changing the direction or the sub-scanning direction, and the timing at which the light receiving element receives the first beam and the timing at which the second beam is received. And detecting means for detecting the optical axis deviation of the second beam, and correcting means for correcting the optical axis deviation of the first beam or the second beam based on the deviation detected by the detecting means. The control means sets a position at which the first beam and the second beam are applied to the scanning region in a period of the one frame to a plurality of continuous scanning lines in the scanning region, and The irradiation position is changed in the sub-scanning direction every one frame period .

  [0010]
    FIG. 1 shows a configuration of an image drawing apparatus according to the present embodiment.
    FIG. 2 shows an arrangement example of a microlens array and a light receiving element.
    FIG. 3 is an image diagram showing a specific example of optical axis misalignment.
    FIG. 4 is a diagram showing a change in the position of a scanning target row in time series and a corresponding change in received light level when a scanning area is scanned one line per frame by a green laser beam.
    FIG. 5 is a diagram showing a change in the position of a scanning target row in a time series and a change in a received light level corresponding to this when a scanning region is scanned one row per frame by a blue laser beam.
    FIG. 6 is a diagram showing a change in the position of a scanning target row in time series and a change in a received light level corresponding to this when a scanning region is scanned one row per frame by a red laser beam.
    [Fig. 7] ViceIt is a flowchart which shows the procedure of the optical axis deviation correction process of a scanning direction.
    FIG. 8 is a diagram showing a change in the position of a pixel to be scanned and a change in received light level in time series when scanning is sequentially performed by one pixel per frame with a green laser beam.
    FIG. 9 is a diagram showing a change in the position of a pixel to be scanned and a change in received light level in a time series when scanning is sequentially performed by one pixel per frame with a blue laser beam;
    FIG. 10 is a diagram showing a change in the position of a pixel to be scanned and a change in a received light level in a time series when scanning is sequentially performed by one pixel per frame with a red laser beam.
    FIG. 11 mainIt is a flowchart which shows the procedure of the optical axis deviation correction process of a scanning direction.
    FIG. 12 is a diagram illustrating the position of a scanning target pixel when the scanning target pixel is on the light receiving element when the light receiving element has a size of 4 pixels.
    FIG. 13 is a diagram illustrating a change in the position of a scanning target row and a light receiving level when the scanning target row is on the light receiving element when the light receiving element is arranged over a plurality of pixels.
    FIG. 14 ViceIt is a figure which shows the position of the scanning object line in a scanning area | region at the time of setting two adjacent lines in a scanning direction as a scanning object line.
    FIG. 15 is a diagram illustrating a position of a scanning target pixel according to a first example of a modification example;
    FIG. 16 is a diagram illustrating a change in a position of a scanning target pixel and a light reception level corresponding to the position of a scanning target pixel according to a second example of the present modification.
    FIG. 17 shows a configuration example of a head-up display.
BEST MODE FOR CARRYING OUT THE INVENTION

  In one preferred embodiment of the present invention, there is provided an optical axis deviation correction apparatus that corrects an optical axis deviation between a first beam emitted from a first light source and a second beam emitted from a second light source, Scanning means for scanning the first beam and the second beam with respect to a scanning region; a light receiving element disposed at a position capable of receiving the first beam and the second beam scanned in the scanning region; Control means for changing a position at which the first beam and the second beam are irradiated in the scanning region in a main scanning direction or a sub-scanning direction for each scanning period of each scan repeated a plurality of times with respect to the scanning region; When the control unit scans the first beam and the second beam with respect to the scanning region, the timing at which the light receiving element receives the first beam and the timing at which the second beam is received. Detecting means for detecting a deviation of the optical axes of the first beam and the second beam according to the difference between the first beam and the second beam, based on the deviation detected by the detecting means. Correction means for correcting the optical axis deviation.

  The optical axis deviation correction device corrects an optical axis deviation between the first beam emitted from the first light source and the second beam emitted from the second light source, and includes a scanning unit, a light receiving element, and a control unit. And detecting means and correcting means. The scanning unit scans the scanning region with the first beam and the second beam. The control means changes the position at which the first beam and the second beam are irradiated in the scanning region in the main scanning direction or the sub-scanning direction for each scanning period of each scan repeated a plurality of times with respect to the scanning region. The detecting means detects the first beam according to the difference between the timing at which the light receiving element receives the first beam and the timing at which the second beam is received when the first beam and the second beam are scanned in the scanning region. And a deviation of the optical axis of the second beam is detected. The correction unit corrects the optical axis shift of the first beam or the second beam based on the shift detected by the detection unit. As described above, the optical axis deviation correcting device scans the scanning region by changing the irradiation position in the main scanning direction or the sub-scanning direction for each scanning period of each scanning repeated a plurality of times with respect to the scanning region. The optical axis deviation is corrected based on the light reception timing of the beam and the light reception timing of the second beam. As a result, the optical axis deviation correction device can easily measure the light reception timing and correct the optical axis deviation without depending on the detection accuracy of the light receiving element, even when the laser beam passes through the light receiving element at high speed. Can be performed.

  In one aspect of the optical axis deviation correcting apparatus, the scanning unit scans the scanning region with the first beam and the second beam over a predetermined scanning period, and the control unit includes the first beam and the second beam. The position irradiated with the second beam is changed in the main scanning direction or the sub-scanning direction for each scan repeated a plurality of times every predetermined unit time at a frame rate, and the detection means is configured to change the position in the unit time. The optical axis shift is detected according to the difference between the timing at which the light receiving element receives the first beam and the second beam. The above unit time indicates 1 second when scanning is performed every 60 FPS (Frames Per Second), for example. In this case, the number of times is 60, and the length of the scanning period is 1/60 seconds. As a result, the optical axis deviation correction device can easily measure the light reception timing and correct the optical axis deviation without depending on the detection accuracy of the light receiving element, even when the laser beam passes through the light receiving element at high speed. Can be performed.

In one aspect of the optical axis misalignment correction apparatus, the control unit determines a position at which the first beam and the second beam are irradiated on the scanning region in the scanning period. set pixel, and changing the sub scanning direction for each of the scanning period. This aspect, the optical axis deviation correcting apparatus, and if the light receiving element is disposed in a boundary area of each pixel, even when the width of the sub-scanning direction is large, a suitably optical axis shift in the sub scanning direction It can be corrected.

In another mode of the optical axis deviation correcting apparatus, the number of the plurality of successive rows being irradiated, the sub-scanning direction of the irradiation region during the unit time on the scanning surface of the light receiving element is arranged Is set to be larger than that of the light receiving element.

In another mode of the optical axis deviation correcting unit, wherein, the amount of changing the irradiation area for each of the scanning period, to a value smaller than the sub-scanning direction size of the light receiving element. These embodiments, the optical axis deviation correcting apparatus, even if the width of the sub-scanning direction of the light receiving element is large, it is possible to preferably correct the optical axis deviation.

In another aspect of the optical axis misalignment correction apparatus, the control unit may determine a position at which the first beam and the second beam are applied to the scanning region in the scanning period for one column in the scanning region. And change in the main scanning direction for each scanning period. By doing so, the optical axis deviation correction apparatus can correct the optical axis deviation in the main scanning direction quickly and with high accuracy.

In another aspect of the optical axis misalignment correction apparatus, the control unit determines a position at which the first beam and the second beam are irradiated on the scanning region in the scanning period in a main scanning direction in the scanning region. Are set to consecutive pixels. By doing so, the optical axis deviation correction apparatus can suitably correct the optical axis deviation in the main scanning direction.

  In another aspect of the optical axis misalignment correction apparatus, the control unit may determine a position at which the first beam and the second beam are irradiated in the scanning region in a main scanning direction or a sub-scan for each scanning period. In the direction, the light receiving element is changed according to the movement width corresponding to the width in the main scanning direction or the sub-scanning direction. According to this aspect, the optical axis deviation correction apparatus can perform optical axis deviation correction more quickly.

In another mode of the optical axis deviation correcting apparatus, the control means, the position where the first beam and the second beam is irradiated at the scanning area, for each of the scanning period, continuously sub scanning direction Or, it is changed toward the main scanning direction. According to this aspect, the optical axis deviation correction apparatus can preferably scan the entire scanning region and measure the light reception timing of the light receiving element.

  In another aspect of the optical axis deviation correcting apparatus, the control unit causes the first beam and the second beam to scan the scanning region separately. According to this aspect, the optical axis deviation correction apparatus can preferably measure the light reception timing of the first beam and the second beam.

  In another aspect of the optical axis misalignment correction apparatus, the light correction element is configured such that the light receiving element in the unit time is scanned when the first beam and the second beam are scanned over the scanning region. The light emission timing of the first light source or the second light source is controlled so that the timing of receiving the first beam matches the timing of receiving the second beam. According to this aspect, the optical axis deviation correction apparatus can suitably correct the optical axis deviation.

  In another preferred embodiment of the present invention, there is provided an optical axis deviation correction device that corrects an optical axis deviation between a first beam emitted from a first light source and a second beam emitted from a second light source, Scanning means for scanning the first beam and the second beam with respect to a scanning region; a light receiving element disposed at a position capable of receiving the first beam and the second beam scanned in the scanning region; A predetermined pattern is drawn on the scanning area by the first beam and the second beam, and the drawing position of the pattern is changed in the main scanning direction or the sub-scanning direction for each scanning period of each scan repeated a plurality of times. And a control unit for causing the light receiving element to receive the first beam and the second beam when the control unit scans the first beam and the second beam with respect to the scanning region. Detection means for detecting a deviation of the optical axes of the first beam and the second beam according to a difference with the timing of receiving the light beam, and based on the deviation detected by the detection means, the first beam or the Correction means for correcting an optical axis shift of the second beam. Even in this embodiment, the optical axis misalignment correction apparatus can easily measure the light reception timing without depending on the detection accuracy of the light receiving element, even when the laser beam passes through the light receiving element at high speed, and the optical axis. Deviation correction can be performed.

  In still another preferred embodiment of the present invention, the optical axis shift between the first beam emitted from the first light source and the second beam emitted from the second light source is corrected, and the first beam and the second beam are corrected. An optical axis misalignment correction apparatus comprising: scanning means for scanning a scanning region with respect to a scanning region; and a light receiving element arranged at a position where the first beam and the second beam scanned on the scanning region can be received. A control method to be executed, wherein a position at which the first beam and the second beam are irradiated in the scanning region is determined in a main scanning direction for each scanning period of each scanning repeated a plurality of times with respect to the scanning region. Alternatively, when the first beam and the second beam are scanned in the scanning region by the control step, the timing at which the light receiving element receives the first beam. And detecting the shift of the optical axis of the first beam and the second beam according to the difference between the timing of receiving the second beam and the second beam, and based on the shift detected by the detection step, And a correction step of correcting an optical axis shift of the first beam or the second beam. By executing this control method, the optical axis misalignment correction device can easily measure the light reception timing without depending on the detection accuracy of the light receiving element, even when the laser light passes through the light receiving element at high speed. It becomes possible to correct the optical axis deviation.

  In still another preferred embodiment of the present invention, an optical axis deviation correction device that corrects an optical axis deviation between a first beam emitted from a first light source and a second beam emitted from a second light source is provided as a light source unit. The optical axis deviation correcting device includes: scanning means for scanning the scanning region with the first beam and the second beam over a predetermined scanning period; and scanning the scanning region. A light receiving element disposed at a position capable of receiving the first beam and the second beam, and a position at which the first beam and the second beam are irradiated in the scanning region, with respect to the scanning region, Control means for changing in the main scanning direction or the sub-scanning direction for each scanning period of each scanning repeated a plurality of times every predetermined unit time, and the first beam and the second beam for the scanning region The light of the first beam and the second beam according to the difference between the timing at which the light receiving element receives the first beam and the timing at which the second beam is received during the unit time. Detecting means for detecting an axis deviation; and correcting means for correcting an optical axis deviation of the first beam or the second beam based on the deviation detected by the detecting means. The head-up display is equipped with the above-mentioned optical axis deviation correction device in the light source unit, so that even when laser light passes through the light receiving element at high speed, the light receiving timing does not depend on the detection accuracy of the light receiving element. Can be easily measured and the optical axis deviation can be corrected.

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

[Configuration of Image Drawing Device]
FIG. 1 shows a configuration of an image drawing apparatus 1 to which an optical axis deviation correction apparatus according to the present invention is applied. As shown in FIG. 1, the image drawing apparatus 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. And comprising. The image drawing apparatus 1 is used as a light source for a head-up display, for example, and emits light constituting a display image to an optical element such as a combiner.

  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 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 “Sc” input from the MEMS mirror 10, and the ASIC (Application) It is configured as a 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.

  The synchronization / image separation unit 31 separates the image data displayed on 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 to the frame memory 4.

  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 a signal representing the light emission pattern of each laser.

  The timing controller 34 controls the operation timing of the synchronization / image separation unit 31 and the bit data conversion unit 32. The timing controller 34 also controls the operation timing of the MEMS control unit 8 described later.

  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. Various data are sequentially read from and written into the RAM 6 as a work memory when the video ASIC 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. The laser driver ASIC 7 includes a red laser driving circuit 71, a blue laser driving circuit 72, and a green laser driving circuit 73.

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

  The MEMS control unit 8 controls the MEMS mirror 10 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 MEMS control unit 8 and the laser driver ASIC 7 function as “control means”.

  The servo circuit 81 controls the operation of the MEMS mirror 10 based on a signal from the timing controller.

  The driver circuit 82 amplifies the control signal of the MEMS mirror 10 output from the servo circuit 81 to a predetermined level and outputs the amplified signal.

  The laser light source unit 9 emits laser light based on the drive signal output from the laser driver ASIC 7. Specifically, the laser light source unit 9 mainly includes a red laser LD1, a blue laser LD2, a green laser LD3, collimator lenses 91a to 91c, reflection mirrors 92a to 92c, a microlens array 94, and a lens. 95 and the light receiving element 100.

  The red laser LD1 emits red laser light (also referred to as “red laser light LR”), the blue laser LD2 emits blue laser light (also referred to as “blue laser light LB”), and the green laser LD3. Green laser light (also referred to as “green laser light LG”) is emitted. The collimator lenses 91a to 91c convert the red, blue, and green laser beams LR, LB, and LG into parallel beams and emit the parallel beams to the reflection mirrors 92a to 92c. The reflection mirror 92b reflects the blue laser light LB, and the reflection mirror 92c transmits the blue laser light LB and reflects the green laser light LG. The reflection mirror 92a transmits only the red laser beam LR and reflects the blue and green laser beams LB and LG. The red laser light LR transmitted through the reflection mirror 92 a and the blue and green laser beams LB and LG reflected by the reflection mirror 92 a are incident on the MEMS mirror 10.

  The arbitrary two laser beams of the lasers LD1, LD2, and LD3 are examples of the “first light source” and the “second light source” in the present invention, and the arbitrary two laser beams of the laser beams LR, LB, and LG. Are examples of the “first beam” and the “second beam” in the present invention.

  The MEMS mirror 10 functions as a “scanning unit” in the present invention, and reflects the laser light incident from the reflection mirror 92a toward a microlens array 94 which is an example of an EPE (Exit Pupil Expander). The MEMS mirror 10 basically moves so as to scan the microlens array 94 as a screen under the control of the MEMS control unit 8 in order to display the image input to the image signal input unit 2. The scanning position information at that time (for example, information such as the angle of the mirror) is output to the video ASIC 3. In the microlens array 94, a plurality of microlenses are arranged, and the laser beam reflected by the MEMS mirror 10 is incident thereon. The lens 95 enlarges an image formed on the radiation surface of the microlens array 94.

  The light receiving element 100 is provided in the vicinity of the microlens array 94. Specifically, the microlens array 94 is provided at a position including a drawing area “RR” (corresponding to an area for displaying an image (video) to be presented to the user; the same shall apply hereinafter). On the other hand, the light receiving element 100 is provided at a position corresponding to a predetermined area outside the drawing area RR. A specific arrangement of the light receiving element 100 will be described later with reference to FIG. The light receiving element 100 is configured by a photoelectric conversion element such as a photodetector, and supplies a detection signal “Sd”, which is an electrical signal corresponding to the amount of incident laser light, to the video ASIC 3.

  The video ASIC 3 detects the optical axis shift of the red laser light LR, the blue laser light LB, and the green laser light LG based on the detection signal Sd from the light receiving element 100. Further, the video ASIC 3 performs processing for correcting the optical axis deviation based on the detected optical axis deviation. Specifically, the video ASIC 3 corrects the optical axis deviation by changing the light emission timing of the red laser LD1, the blue laser LD2, and / or the green laser LD3. At this time, the video ASIC 3 changes the above-described adjustment amount of the light emission timing based on whether the optical axis shift direction is the main scanning direction or the sub-scanning direction. Thus, the video ASIC 3 functions as “detection means” and “correction means” in the present invention.

  FIG. 2 is a diagram illustrating an arrangement example of the microlens array 94 and the light receiving element 100. FIG. 2 shows a diagram in which the microlens array 94 and the light receiving element 100 are observed from the direction along the traveling direction of the laser light (the arrow “Z” direction in FIG. 1). A scannable region “SR” represented by a broken line is a region corresponding to a range where scanning by the MEMS mirror 10 is possible, that is, a range where drawing is possible. A microlens array 94 is disposed in the scannable region SR. A region represented by a one-dot chain line in the microlens array 94 indicates a drawing region RR.

  The light receiving element 100 is an area within the scannable area SR and is provided below the microlens array 94. That is, the light receiving element 100 is provided at a position corresponding to a region outside the drawing region RR so as not to disturb the display. In this example, the position of the light receiving element 100 is on the arrangement surface of the microlens array 94, but is not limited thereto, and may be anywhere within the scannable region SR.

The MEMS mirror 10 causes an image (video) to be displayed to be drawn in the drawing region RR by scanning the laser beam a plurality of times (that is, performing a raster scan) as indicated by an arrow in FIG. In this specification, as shown below in Figure 2, call the main scanning direction of the laser beam as "lateral direction", a vertical sub-scanning direction to the main scanning direction is also referred to as a "vertical direction".

  Further, the MEMS mirror 10 scans a laser beam for a predetermined scanning region “Rtag” including the position of the light receiving element 100 within the scanable region SR and outside the drawing region RR when correcting the optical axis deviation. . A specific scanning method will be described later.

  The position where the light receiving element 100 is disposed is not limited to that shown in FIG. The light receiving element 100 can be arranged at various positions as long as it is located in the scannable area SR and corresponds to an area outside the drawing area RR.

  Next, a specific example of the optical axis deviation will be described with reference to FIG. FIG. 3A shows an example of the red laser light LR, the blue laser light LB, and the green laser light LG emitted from the image drawing device 1. Here, the case where the optical axis shift has arisen in red laser beam LR, blue laser beam LB, and green laser beam LG is illustrated. FIG. 3B corresponds to each of the red laser light LR, the blue laser light LB, and the green laser light LG irradiated on the microlens array 94 disposed at the position “P” in FIG. An example of a spot to be performed is shown. In FIG. 3B, the circles with the letters “R”, “B”, and “G” written therein indicate the spots of the red laser beam LR, the blue laser beam LB, and the green laser beam LG, respectively. (The same shall apply hereinafter). In this example, the optical axis of the blue laser light LB is shifted upward by 2 pixels (dots) relative to the optical axis of the red laser light LR, and the optical axis of the green laser light LG is the red laser light. With respect to the optical axis of LR, it is shifted downward by 2 pixels and is shifted rightward by 1 pixel. In the present embodiment, the image drawing apparatus 1 controls the light emission timings of the lasers LD1 to LD3 so that the optical axes of the laser beams LR, LB, and LG coincide when such an optical axis shift occurs. .

[Optical axis deviation correction method]
Hereinafter, the optical axis deviation correcting method according to the present embodiment will be specifically described. The image drawing apparatus 1 performs optical axis deviation correction at a predetermined timing such as when a predetermined input is received from the user or when the image drawing apparatus 1 is activated. The image drawing apparatus 1, first, after the correction of the optical axis deviation of the sub-scanning direction, performing a correction process in the main scanning direction of the optical axis deviation. Each of these correction processes will be specifically described below.
(1) the optical axis deviation correcting process in the sub-scanning direction will be described first optical axis deviation correcting method of the sub-scanning direction. Schematically, the image drawing apparatus 1 sequentially scans one line per frame from the top row of the scanning region Rtag by each laser beam, and the light receiving element 100 detects the received light at each frame for each laser beam. Based on whether or not, the optical axis deviation is detected and corrected. Note that the image drawing apparatus 1 draws each frame for each scanning period of each scan repeated a plurality of times per unit time. For example, in the case of 60 FPS, the image drawing apparatus 1 draws each frame for each scanning period of each scan repeated 60 times per second.

Here, specific examples of the optical axis deviation correcting method of the sub-scanning direction will be described with reference to FIGS. 4 to 6 for the case where the optical axis deviation occurs. Hereinafter, the number indicating the frame number when counting from the frame in which the uppermost row of the scanning region Rtag is scanned is referred to as “frame number Nf”, and the light receiving element 100 detects the highest light receiving level. This frame number is also referred to as “detection frame number Nfd”. A row (scanning line) in the scanning region Rtag to be scanned for each frame is also referred to as a “scanning target row Ltag”.

  FIG. 4 is a diagram showing a change in the position of the scan target row Ltag in a time series and a change in the light reception level detected by the light receiving element 100 when the scanning region Rtag is scanned one row per frame by the green laser beam LG. It is. Specifically, FIGS. 4A to 4E show the positions of the scan target row Ltag corresponding to the frames having the frame numbers Nf of “1” to “5”, respectively, and FIGS. j) shows the change in the light receiving level detected by the light receiving element 100 during the scanning shown in FIGS. Similarly, FIG. 5 shows a change in the position of the scan target row Ltag and a change in the received light level detected by the light receiving element 100 in time series when scanning is performed on the blue laser beam LB, and FIG. It is a figure which shows the change of the position of the scanning object line Ltag and the change of the light reception level which the light receiving element 100 detects in the time series at the time of performing a scan for the red laser beam LR.

  As shown in FIGS. 4 to 6, in this example, the blue laser beam LB has an optical axis shift of one pixel in the downward direction with respect to the green laser beam LG, and the red laser beam LR in the upward direction. An optical axis shift for one pixel occurs. Therefore, in this case, the detection frame number Nfd of each laser beam differs depending on the direction and width of the optical axis deviation. Specifically, the frame number Nfd when detecting the green laser beam LG is “3” (see FIGS. 4C and 4H), whereas the frame number Nfd when detecting the blue laser beam LB is “2”. (See FIGS. 5B and 5G), and the frame number Nfd at the time of detection of the red laser beam LR is “4” (see FIGS. 6D and 6I).

  As described above, when the frame numbers Nfd at the time of detection of the respective laser beams are different, the image drawing apparatus 1 sets the optical axis of the predetermined laser beam as a reference (fixed) and uses the reference laser beam (“reference laser beam”). Also, the optical axis of the other laser beam is moved based on the difference between the detection frame number Nfd and the other laser beam detection frame number Nfd. More specifically, the image drawing device 1 sets the optical axis of the laser beam having the detection frame number Nfd smaller than the detection frame number Nfd of the reference laser beam Lst to the difference between the detection frame numbers Nfd. The optical axis of the laser beam having a detection frame number Nfd that is larger than the detection frame number Nfd when the reference laser beam Lst is detected is equivalent to the difference between the detection frame numbers Nfd. Move down by the number of pixels you want.

  Therefore, in the example of FIGS. 4 to 6, when the green laser light LG is used as the reference laser light Lst, the image drawing apparatus 1 detects the blue laser light LB when detecting the blue laser light LB than the detection time frame number Nfd. Since the number Nfd is smaller by “1”, the optical axis of the blue laser beam LB is moved upward by one pixel. Further, the image drawing apparatus 1 has the detection time frame number Nfd of the red laser light LR larger by “1” than the detection time frame number Nfd of the green laser light LG, so that the optical axis of the red laser light LR is directed downward. Move one pixel.

  As described above, the image drawing apparatus 1 scans each row of laser light by one row per frame, so that the light in the vertical direction for each pixel is compared with the case of scanning all rows in one frame. Axial misalignment can be detected with high accuracy and optical axis misalignment can be corrected. The scan target row Ltag is an example of the “pattern” in the present invention.

Figure 7 is an example of a flowchart showing a processing procedure for correcting the optical axis deviation of the sub-scanning direction. The image drawing apparatus 1 repeatedly executes the processing of the flowchart shown in FIG. 7 according to a predetermined cycle.

  First, the image drawing apparatus 1 turns on the reference laser beam Lst, and scans the scanning region Rtag one by one for each frame in order from the top (step S101). Here, the image drawing apparatus 1 selects the green laser beam LG as the reference laser beam Lst. Then, the image drawing apparatus 1 determines whether or not the light receiving element 100 detects laser light for each frame (step S102). When the light receiving element 100 detects the laser beam (step S102; Yes), the image drawing apparatus 1 advances the process to step S103. At this time, the image drawing apparatus 1 specifies the detection frame number Nfd when the light receiving element 100 detects the green laser light LG. On the other hand, when the light receiving element 100 does not detect the laser beam (step S102; No), the image drawing device 1 shifts the scanning target row Ltag downward by one row and continues scanning one row per frame (step). S101).

  Next, in step S103, the image drawing apparatus 1 turns on a predetermined laser beam (in this case, the blue laser beam LB) other than the reference laser beam Lst, and targets 1 per frame for the scanning region Rtag. Scanning is performed for each row in order from the top (step S103). Then, for each frame, the image drawing apparatus 1 determines whether or not the light receiving element 100 has detected laser light (step S104). When the light receiving element 100 has detected laser light (step S104; Yes), The process proceeds to step S105. At this time, the image drawing apparatus 1 specifies the detection frame number Nfd when the light receiving element 100 detects the blue laser beam LB. On the other hand, when the light receiving element 100 does not detect the laser beam (step S104; No), the image drawing apparatus 1 continues scanning by shifting the scanning target row Ltag by one row downward (step S103).

Next, in step S105, the image drawing apparatus 1 determines whether the detection frame number Nfd when the light receiving element 100 detects the blue laser beam LB in step S104 is the same as the detection frame number Nfd of the reference laser beam Lst. It is determined whether or not (step S105). Thus, the image drawing unit 1 determines whether the optical axis shift of the sub-scanning direction between the blue laser beam LB running scanning green laser beam LG is a reference laser beam Lst. Then, when the reference laser beam Lst and the detection time of the frame number Nfd were identical (step S105; Yes), the image drawing unit 1 determines that in these laser light having no optical axis shift of the sub-scanning direction, The process proceeds to step S107. On the other hand, the reference laser beam Lst if detected during a frame number Nfd are not identical (step S105; No), the image drawing unit 1, the optical axis of the blue laser beam LB in accordance with the deviation of the detection time frame number Nfd sub Move in the scanning direction (step S106). Thus, the image drawing unit 1 and the optical axis of the blue laser light LB of the green laser beam LG is a reference laser beam Lst, to match in the sub-scanning direction.

  Next, in step S107, the image drawing apparatus 1 turns on the unscanned red laser light LR, and scans the scanning region Rtag one by one for each frame in order from the top (step S107). Then, the image drawing apparatus 1 determines whether or not the light receiving element 100 has detected laser light (step S108). When the light receiving element 100 has detected laser light (step S108; Yes), the image drawing apparatus 1 The process proceeds to step S109. At this time, the image drawing apparatus 1 specifies the detection frame number Nfd when the light receiving element 100 detects the red laser light LR. On the other hand, when the light receiving element 100 does not detect the laser beam (step S108; No), the image drawing apparatus 1 continues scanning by shifting the scanning target row Ltag by one row downward (step S107).

In step S109, the image drawing apparatus 1 determines whether or not the detection time frame number Nfd of the red laser light LR is the same as the detection time frame number Nfd of the reference laser light Lst (step S109). When the hour frame numbers Nfd are the same (step S109; Yes), the process of the flowchart is ended. On the other hand, if the reference laser beam Lst and the detection time of the frame number Nfd are not identical (step S109; No), the image drawing unit 1, the optical axis of the red laser beam LR according to the deviation of the detection time frame number Nfd sub Move in the scanning direction (step S110). Thus, the image drawing unit 1 and the optical axis of the red laser beam LR of the green laser beam LG is a reference laser beam Lst, to match in the sub-scanning direction.

  As described above, the image drawing apparatus 1 preferably moves each optical beam of the laser light other than the reference laser light Lst according to the difference in timing at which the light receiving element 100 receives each laser light. The optical axes can be matched.

(2) the main scanning direction of the optical axis deviation correcting process will be described in the main scanning direction of the optical axis deviation correcting method. Schematically, the image drawing apparatus 1 scans each laser beam by detecting the frame number at the time of detection for each laser beam by sequentially scanning from the pixel in the top row of the scanning region Rtag by one pixel (dot) per frame. Nfd is calculated, and the optical axis deviation is detected and corrected so that the detected frame numbers Nfd coincide. Incidentally, preferably, the image drawing device 1, after performing the optical axis deviation correcting process in the sub-scanning direction as described above, performs the optical axis deviation correcting process in the main scanning direction.

Here, a specific example of the optical axis deviation correction method in the main scanning direction when the optical axis deviation occurs will be described with reference to FIGS. Hereinafter, when correcting the optical axis deviation in the main scanning direction, the pixel (pixel) of the scanning region Rtag to be scanned for each frame is also referred to as “scanning target pixel Ptag”.

  FIG. 8 shows the position of the scan target row Ltag in time series when the green laser beam LG, which is the reference laser beam Lst, is sequentially scanned from the pixel in the uppermost row of the scan region Rtag by one pixel per frame. It is a figure which shows the change of this, and the change of the light reception level which the light receiving element 100 detects. Specifically, FIGS. 8A to 8E show the positions of the scan target pixels Ptag corresponding to the frames having the frame numbers Nf of “1”, “19” to “21”, and “40”, respectively. FIGS. 8F to 8J show changes in the received light level during scanning shown in FIGS. 8A to 8E, respectively. Similarly, FIG. 9 shows a change in the position of the scanning target row Ltag and a change in the light receiving level detected by the light receiving element 100 when scanning is performed on the blue laser light LB, and FIG. 10 shows the red laser light LR. FIG. 6 is a diagram illustrating a change in a position of a scan target row Ltag and a change in a light receiving level detected by the light receiving element 100 when scanning is performed on the target.

  As shown in FIGS. 8 to 10, in this example, the blue laser beam LB has an optical axis shift of one pixel in the right direction with respect to the green laser beam LG that is the reference laser beam Lst, and the red laser The optical axis of the light LR is shifted by one pixel in the left direction. Therefore, in this case, the detection frame number Nfd of each laser beam differs depending on the direction and width of the optical axis deviation. Specifically, the frame number Nfd when detecting the green laser beam LG is “20” (see FIGS. 8C and 8H), whereas the frame number Nfd when detecting the blue laser beam LB is “19”. (See FIGS. 9B and 9G), and the frame number Nfd at the time of detection of the red laser beam LR is “21” (see FIGS. 10D and 10I).

  As described above, when the frame numbers Nfd at the time of detection of the respective laser beams are different, the image drawing apparatus 1 causes a shift between the frame numbers Nfd at the time of detection of the reference laser beam Lst and the frame numbers Nfd at the time of detection of other laser beams. Based on this, the moving direction and moving width of the optical axis of the other laser light are determined. More specifically, the image drawing device 1 sets the optical axis of the laser beam having the detection frame number Nfd smaller than the detection frame number Nfd of the reference laser beam Lst to the difference between the detection frame numbers Nfd. The optical axis of the laser beam having the detection frame number Nfd that is larger than the detection frame number Nfd when the reference laser beam Lst is detected corresponds to the difference between the detection frame numbers Nfd. Move to the right by the number of pixels you want.

  Accordingly, in the example of FIGS. 8 to 10, the image drawing apparatus 1 uses the blue laser because the frame number Nfd when detecting the blue laser beam LB is smaller by “1” than the frame number Nfd when detecting the green laser beam LG. The optical axis of the light LB is moved leftward by one pixel. Further, the image drawing apparatus 1 has the detection time frame number Nfd of the red laser light LR larger by “1” than the detection time frame number Nfd of the green laser light LG, so that the optical axis of the red laser light LR is directed rightward. Move one pixel.

  As described above, the image drawing apparatus 1 scans each laser beam by one pixel per frame, so that the laser beam on the light receiving element 100 is compared with the case where the entire scanning region Rtag is scanned in one frame. Without being affected by the speed at which the light passes, the optical axis deviation in the horizontal direction for each pixel can be detected with high accuracy, and the optical axis deviation can be corrected. The scanning target pixel Ptag is an example of the “pattern” in the present invention.

FIG. 11 is an example of a flowchart showing a processing procedure for correcting the optical axis deviation in the main scanning direction. The image drawing apparatus 1 executes the process of the flowchart shown in FIG. 11 after the execution of the flowchart shown in FIG.

  First, the image drawing apparatus 1 turns on the reference laser beam Lst, and scans the scanning region Rtag in order from the upper left corner pixel by one pixel per frame (step S201). Here, the image drawing apparatus 1 selects the green laser beam LG as the reference laser beam Lst. Then, the image drawing apparatus 1 determines whether or not the light receiving element 100 detects laser light for each frame (step S202). When the light receiving element 100 detects the laser beam (step S202; Yes), the image drawing apparatus 1 advances the process to step S203. At this time, the image drawing apparatus 1 specifies the detection frame number Nfd when the light receiving element 100 detects the green laser light LG. On the other hand, when the light receiving element 100 does not detect the laser beam (step S202; No), the image drawing apparatus 1 adjoins the scanning target pixel Ptag in the downward direction when the pixel adjacent to the right or the scanning target pixel Ptag is at the right end. The scanning is continued by setting the pixel at the left end of the row to be performed (step S201).

  Next, in step S203, the image drawing apparatus 1 turns on a predetermined laser beam (in this case, the blue laser beam LB) other than the reference laser beam Lst, and targets 1 per frame for the scanning region Rtag. Scanning is performed in order from the upper left corner pixel by pixel (step S203). Then, the image drawing apparatus 1 determines whether or not the light receiving element 100 detects the laser beam for each frame (step S204), and when the light receiving element 100 detects the laser light (step S204; Yes), The process proceeds to step S205. At this time, the image drawing apparatus 1 specifies the detection frame number Nfd when the light receiving element 100 detects the blue laser beam LB. On the other hand, when the light receiving element 100 does not detect the laser beam (step S204; No), the image drawing apparatus 1 moves downward when the pixel to be scanned Ptag is adjacent to the right or when the pixel to be scanned Ptag is at the right end. Next, scanning is performed by setting the pixel at the left end of the row adjacent to (step S203).

Next, in step S205, the image drawing apparatus 1 determines whether the detection frame number Nfd when the light receiving element 100 detects the blue laser light LB in step S204 is the same as the detection frame number Nfd of the reference laser light Lst. It is determined whether or not (step S205). As a result, the image drawing apparatus 1 determines whether or not there is an optical axis shift in the main scanning direction between the green laser light LG that is the reference laser light Lst and the blue laser light LB that has been scanned. If the reference laser beam Lst and the detection frame number Nfd are the same (step S205; Yes), the image drawing apparatus 1 determines that these laser beams have no optical axis deviation in the main scanning direction, The process proceeds to step S207. On the other hand, when the reference laser beam Lst and the detection frame number Nfd are not the same (step S205; No), the image drawing apparatus 1 mainly sets the optical axis of the blue laser beam LB in accordance with the deviation of the detection frame number Nfd. Move in the scanning direction (step S206). As a result, the image drawing apparatus 1 matches the optical axis of the green laser light LG, which is the reference laser light Lst, with the optical axis of the blue laser light LB in the main scanning direction.

  Next, in step S207, the image drawing apparatus 1 turns on the unscanned red laser light LR, and scans the scanning region Rtag one by one from the pixel in the upper left corner in order (step S207). S207). Then, the image drawing apparatus 1 determines whether or not the light receiving element 100 has detected laser light (step S208). When the light receiving element 100 has detected laser light (step S208; Yes), the image drawing apparatus 1 The process proceeds to step S209. At this time, the image drawing apparatus 1 specifies the detection frame number Nfd when the light receiving element 100 detects the red laser light LR. On the other hand, when the light receiving element 100 does not detect the laser light (step S208; No), the image drawing apparatus 1 moves downward when the pixel to be scanned Ptag is adjacent to the right side or when the pixel to be scanned Ptag is at the right end. Next, scanning is continued by setting the pixel at the left end of the row adjacent to (step S207).

In step S209, the image drawing apparatus 1 determines whether or not the detection time frame number Nfd of the red laser light LR is the same as the detection time frame number Nfd of the reference laser light Lst (step S209). If the hour frame numbers Nfd are the same (step S209; Yes), the process of the flowchart is terminated. On the other hand, when the reference laser beam Lst and the detection frame number Nfd are not the same (step S209; No), the image drawing apparatus 1 mainly sets the optical axis of the red laser beam LR according to the deviation of the detection frame number Nfd. Move in the scanning direction (step S210). As a result, the image drawing apparatus 1 matches the optical axis of the green laser light LG, which is the reference laser light Lst, with the optical axis of the red laser light LR in the main scanning direction.

  As described above, the image drawing apparatus 1 preferably moves each optical beam of the laser light other than the reference laser light Lst according to the difference in timing at which the light receiving element 100 receives each laser light. The optical axes can be matched.

[Modification]
Next, modified examples suitable for the present invention will be described. The following modifications may be applied to the above-described embodiments in combination.

(Modification 1)
4 to 6 and 8 to 10, the light receiving element 100 has a size of one pixel and is arranged at a position overlapping only with one predetermined pixel. However, the configuration to which the present invention is applicable is not limited to this. Instead of this, the light receiving element 100 may have a size of one pixel or more, and may be arranged at a position overlapping a plurality of pixels.

First, the case where the size of the light receiving element 100 is 2 pixels or more will be specifically described with reference to FIG. 12 by taking an optical axis deviation correction process in the main scanning direction as an example.

  FIG. 12 shows changes in the position of the scanning target pixel Ptag and the light receiving level detected by the light receiving element 100 when the scanning target pixel Ptag is on the light receiving element 100 when the light receiving element 100 has a size of 4 pixels. FIG. Specifically, in FIGS. 12A to 12D, the positions of the scan target pixels Ptag corresponding to the frames having the frame numbers Nf of “12”, “13”, “20”, and “21”, respectively. Show.

  As shown in FIG. 12, in this case, the light receiving element 100 detects light reception over four frames. Therefore, in this case, the image drawing apparatus 1 sets the frame number Nfd at the time of detection to, for example, the median value (in this case, “13” or “20”) of the frame number Nf when light reception is detected, or the light reception level is the highest. It is set to the frame number Nf corresponding to the time of high scanning or the frame number Nf for scanning having the longest detection period. In these cases, the image drawing apparatus 1 needs to scan all the pixels in the scanning region Rtag. Therefore, the image drawing apparatus 1 does not determine whether or not the light receiving element 100 detects light reception in steps S104 and S108 in FIG. 7 and steps S204 and S208 in FIG. Determine if a row or pixel has been scanned.

Similarly, in the case of correcting the optical axis of the sub-scanning direction when the light receiving element 100 having a size of more than 2 pixels is an image drawing apparatus 1, the detection time frame number Nfd, when it is detected light It is set to the median value of the frame number Nf, or the frame number Nf corresponding to the scanning with the highest light reception level, or the average value of the frame numbers Nf at which light reception is detected. Then, the image drawing apparatus 1 moves the optical axis of the laser light other than the reference laser light Lst according to the difference in the detection frame number Nfd, as in the description of the embodiment.

Next, a case where the light receiving element 100 is disposed at a position overlapping part and a plurality of pixels will be specifically described with reference to FIG. 13 as an example of the optical axis deviation correcting process in the sub-scanning direction.

  FIG. 13 shows the detection of the position of the scanning target row Ltag and the light receiving device 100 when the scanning target row Ltag is on the light receiving device 100 when the light receiving device 100 is arranged so as to partially overlap a plurality of pixels. It is a figure which shows the change of the received light level. Specifically, FIGS. 13A and 13B show the position of the scan target row Ltag in the third frame and the fourth frame, respectively, and FIGS. 13C and 13D show the positions of 3 and 4, respectively. The change of the light reception level at the time of scanning in the frame and the fourth frame is shown.

  As shown in FIGS. 13A and 13B, in this case, the light receiving element 100 receives light when scanning two frames corresponding to the case where the scanning target row Ltag is the third row and the fourth row, respectively. Detect. On the other hand, the area in which the pixels in the third row overlap with the light receiving element 100 is larger than the pixels in the fourth row. Therefore, as shown in FIGS. 13C and 13D, the light reception level corresponding to the scanning of the frame having the frame number Nf “3” corresponds to the scanning of the frame having the frame number Nf of “4”. It is higher than the light reception level. Therefore, in this case, the image drawing device 1 sets the frame number Nf (here “3”) having the highest light reception level as the frame number Nfd at the time of detection.

Similarly, scanning the light receiving element 100 in the case of an optical axis deviation correcting process in the sub-scanning direction when placed partially overlapping a plurality of pixels, the image drawing device 1, the light receiving level becomes highest The frame number Nf corresponding to the time is set to the detection frame number Nfd. Then, the image drawing apparatus 1 moves the optical axis of the laser light other than the reference laser light Lst according to the difference in the detection frame number Nfd, as in the description of the embodiment.

  Note that when the light receiving element 100 has a size of one pixel or more, or / and is disposed at a position that partially overlaps a plurality of pixels, the image drawing device 1 includes a modification 2 and a later-described modification. By executing the processing according to the third modification, the optical axis deviation can be corrected with higher accuracy.

(Modification 2)
When the optical axis deviation correcting process in the sub-scanning direction, the image drawing unit 1 is a scanning line of interest Ltag was set on one line of pixels, the method to which the present invention is applicable is not limited thereto. Instead of this, the image drawing apparatus 1 may set a plurality of rows of pixels as the scan target row Ltag. This will be specifically described with reference to FIG.

Figure 14 is a diagram illustrating the position of the scanned line Ltag being scanned region Rtag of setting the two rows of pixels adjacent to the scanned row Ltag in the sub scanning direction. Specifically, FIG. 14A shows the position of the scan target row Ltag in the frame with the frame number “2”, and FIG. 14B shows the scan target in the frame with the frame number “3”. The position of the row Ltag is shown, and FIG. 14C shows the position of the scan target row Ltag in the frame whose frame number is “4”.

  As shown in FIG. 14, the image drawing apparatus 1 scans all the rows in the scanning region Rtag by shifting the scanning target row Ltag downward by one row for each frame. Then, the image drawing apparatus 1 calculates the average value of the light reception level for each frame, and sets the frame number having the highest average value as the detection frame number Nfd. In FIG. 14, since the area of the light receiving element 100 that overlaps the scanning target row Ltag becomes the largest during the scanning of the third frame, the image drawing apparatus 1 sets the detection frame number Nfd to “3”.

  As described above, the image drawing device 1 accurately specifies the frame number Nfd at the time of detection of each laser beam even when a plurality of adjacent rows are set as the scan target row Ltag, and the frame number Nfd at the time of detection is determined. Based on the difference, the optical axis deviation can be corrected appropriately. In particular, the image drawing apparatus 1 appropriately determines the frame number Nfd at the time of detection of each laser beam even when the light receiving elements 100 are arranged in an overlapping manner over a plurality of rows as in the example shown in FIG. Therefore, the optical axis shift can be corrected more accurately.

Also, preferably, the image drawing device 1 may determine the number of rows specified in the scanning line of interest Ltag based on the width of the light-receiving element 100 in the sub-scanning direction. For example, the image drawing apparatus 1 designates the number of rows (“2” in the example of FIG. 14) at the position overlapping with the light receiving element 100 as the number of rows to be scanned Ltag. By doing in this way, the image drawing device 1 can uniquely determine the detection frame number Nfd corresponding to the position of the light receiving element 100 even when the area where the light receiving element 100 is arranged is large, Optical axis deviation can be corrected with higher accuracy.

(Modification 3)
In the description of FIGS. 8 to 10, the image drawing apparatus 1 sets the scanning target pixel Ptag to one pixel at the time of correcting the optical axis deviation in the main scanning direction. It is not limited. Instead of this, the image drawing apparatus 1 may set a plurality of pixels as the scanning target pixel Ptag. This will be described with reference to two specific examples of the first example and the second example.

  First, a first example will be described with reference to FIG. FIG. 15 is a diagram illustrating the position of the scan target pixel Ptag according to the first example of the present modification. Specifically, FIGS. 15A to 15C show the positions of the scan target pixels Ptag corresponding to the frames having the frame numbers Nf of 3 to 5, respectively.

  As shown in FIG. 15, in the first example, the image drawing device 1 designates one column of pixels as the scanning target pixel Ptag, and puts it to the leftmost in the scanning region Rtag for each column per frame. Scanning is performed in order from the position of the line to the rightmost line. Then, the image drawing apparatus 1 sets the frame number Nfd at the time of detection to the number of the frame in which the light receiving element 100 detects the received light. In addition, when there are a plurality of frames in which the light receiving element 100 detects light reception, the image drawing apparatus 1 sets the frame number Nf at the time of detecting the highest light reception level, for example, as the detection frame number Nfd.

As described above, according to the first example, since scanning is performed for each column per frame, the image drawing apparatus 1 can shorten the time required for the optical axis deviation correction processing in the main scanning direction. Further, according to the first embodiment, the image drawing unit 1, before performing the optical axis deviation correcting process in the sub-scanning direction, it is also to perform an optical axis deviation correcting process in the main scanning direction.

In the first example, similarly to the second modification, the image drawing apparatus 1 scans a plurality of consecutive columns per frame and shifts the column to be scanned one column at a time. Good. As a result, similarly to the second modification, even when the light receiving element 100 is arranged near the boundary between columns, or when the width of the light receiving element 100 in the main scanning direction is larger than one pixel. The image drawing apparatus 1 can uniquely set the detection frame number Nfd and correct the optical axis deviation.

  Next, a second example will be described with reference to FIG. FIG. 16 is a diagram illustrating the position of the scanning target pixel Ptag according to the second example of the present modification and the change in the received light level corresponding thereto. Specifically, FIGS. 16A to 16E show the positions of the scanning target pixels Ptag at the time of scanning in the respective frames whose frame numbers Nf are “13” to “17”, respectively, and FIG. ... (J) show changes in the received light level detected during the scanning shown in FIGS.

  As shown in FIGS. 16A to 16E, in this example, the image drawing apparatus 1 designates three pixels adjacent in the left-right direction as scanning target pixels Ptag, and moves one pixel to the right by one frame. When the scanning target pixel Ptag is moved and all the pixels in the row being scanned are scanned, the three pixels at the left end of the lower adjacent row are scanned as the scanning target pixel Ptag. As shown in FIGS. 16B to 16D, in this example, the light receiving element 100 detects light reception in the 14th to 16th frames. In this case, for example, the image drawing apparatus 1 sets the frame number Nf (“15” in the example of FIG. 16) corresponding to the median value among the consecutive frame numbers Nf in which light reception is detected as the detection frame number Nfd. As described above, the image drawing apparatus 1 can more reliably suppress the detection omission of received light and the like and increase the accuracy of the optical axis deviation correction by designating a plurality of pixels as the scanning target pixel Ptag.

(Modification 4)
In the above description of the embodiments and modifications, the image drawing unit 1, the optical axis deviation correcting process in the sub-scanning direction, only one line scanned line Ltag is moved downward for each frame. Alternatively, the image drawing apparatus 1 may determine the movement width of the scan target row Ltag according to the width in the sub scanning direction of the light receiving element 100. For example, image drawing apparatus 1, the movement width of the scanned row LTAG, set to less than the width in the sub scanning direction of the light receiving element 100. Specifically, when the width of the sub-scanning direction of the light receiving element 100 is less than 2 pixels or more and 3 pixels, the image drawing unit 1 sets the movement width of the scanned object line Ltag two rows (pixels). This also image drawing device 1 can be detected with a laser beam to the light receiving element 100, and can quickly complete the optical axis deviation correcting process in the sub-scanning direction.

Similarly, the image drawing unit 1, the optical axis deviation correcting process in the main scanning direction, instead of moving only one pixel per frame scanned pixel PTAG, according to the width in the main scanning direction of the light receiving element 100 scanning The movement width of the target pixel Ptag may be determined. For example, the image drawing apparatus 1 sets the movement width of the scanning target pixel Ptag to be equal to or smaller than the width of the light receiving element 100 in the main scanning direction. Also by this, the image drawing apparatus 1 can cause the light receiving element 100 to detect the laser beam and can quickly complete the optical axis deviation correction process in the main scanning direction.

(Modification 5)
The above-described image drawing apparatus 1 is preferably applied to a head-up display. A specific example of this will be described with reference to FIG.

  FIG. 17 shows a configuration example of a head-up display according to the present invention. The head-up display shown in FIG. 17 causes the driver to visually recognize the virtual image “Iv” via the combiner 26.

  In the configuration shown in FIG. 17, the light source unit 1A functions as the image drawing device 1 of the above-described embodiment. The light source section 1A is attached to the ceiling section 22 in the passenger compartment via the support members 11a and 11b, and includes map information including the current location, route guidance information, traveling speed, and other information for assisting driving (hereinafter referred to as “driving assistance”). Light constituting a display image indicating “information” is emitted toward the combiner 26. Specifically, the light source unit 1A generates an original image (real image) of the display image in the light source unit 1 and emits light constituting the image to the combiner 26, thereby allowing the driver to visually recognize the virtual image Iv. .

  The combiner 26 projects a display image emitted from the light source unit 1 and reflects the display image to the driver's viewpoint (eye point) “Pe” to display the display image as a virtual image Iv. And the combiner 26 has the support shaft part 27 installed in the ceiling part 22, and rotates the support shaft part 27 as a spindle. The support shaft portion 27 is installed, for example, in the vicinity of the ceiling portion 22 near the upper end of the front window 20, in other words, in the vicinity of a position where a sun visor (not shown) for the driver is installed.

  Note that the configuration of the head-up display to which the present invention is applicable is not limited to this. For example, the head-up display does not include the combiner 26, and the light source unit 1A may reflect the display image on the front window 20 to the driver's eye point Pe by projecting the light onto the front window 20. The position of the light source unit 1 </ b> A is not limited to being installed on the ceiling unit 22, and may be installed inside the dashboard 24. In this case, the dashboard 24 is provided with an opening for allowing light to pass through the combiner 26 or the front window 20.

  The present invention can be used for various video devices using RGB lasers, such as laser projectors, head-up displays, and head-mounted displays.

1 Image drawing device 3 Video ASIC
7 Laser driver ASIC
8 MEMS control unit 9 Laser light source unit 100 Light receiving element

Claims (9)

A projection device for projecting an image ,
Scanning means for scanning the first beam emitted from the first light source and the second beam emitted from the second light source along the scanning line with respect to the scanning region at a predetermined frame rate;
A light receiving element disposed at a position capable of receiving the first beam and the second beam scanned in the scanning region;
Control means for changing the position at which the first beam and the second beam are irradiated in the scanning region in the main scanning direction or the sub-scanning direction for each frame period with respect to the scanning region;
Detecting means for detecting an optical axis shift of the first beam and the second beam according to a difference between a timing at which the light receiving element receives the first beam and a timing at which the second beam is received;
Correction means for correcting the optical axis deviation of the first beam or the second beam based on the deviation detected by the detection means;
Have
The control means sets a position at which the first beam and the second beam are applied to the scanning region in a period of the one frame to a plurality of continuous scanning lines in the scanning region, and the 1 A projection apparatus, wherein the irradiation position is changed in the sub-scanning direction every frame period. The number of the plurality of continuous scanning lines to be irradiated is such that the size of the irradiation region in the sub-scanning direction in the period of the one frame on the scanning surface on which the light receiving element is arranged is larger than that of the light receiving element. The projection apparatus according to claim 1, wherein the projection apparatus is set to be The projection apparatus according to claim 2, wherein the control unit sets an amount of changing the irradiation area for each period of the one frame to a value smaller than the size of the light receiving element in the sub-scanning direction. The control means determines the position at which the first beam and the second beam are irradiated in the scanning region in the main scanning direction or the sub-scanning direction in the main scanning direction or the sub-scanning direction for each frame period. 4. The projection apparatus according to claim 1, wherein the projection apparatus changes in accordance with a movement width corresponding to a width in a direction or a sub-scanning direction. 5. 5. The projection apparatus according to claim 1, wherein the control unit causes the first beam and the second beam to separately scan the scanning area. 6. When the first beam and the second beam are scanned with respect to the scanning region, the correction unit detects the timing at which the light receiving element receives the first beam in the period of the one frame and the second beam. 6. The projection apparatus according to claim 1, wherein the light emission timing of the first light source or the second light source is controlled so that the timing at which the light is received coincides. A projection device for projecting an image ,
Scanning means for scanning the first beam emitted from the first light source and the second beam emitted from the second light source along the scanning line with respect to the scanning region at a predetermined frame rate;
A light receiving element disposed at a position capable of receiving the first beam and the second beam scanned in the scanning region;
Control means for drawing a predetermined pattern on the scanning region by the first beam and the second beam, and changing the drawing position of the pattern in the main scanning direction or the sub-scanning direction every period of the one frame; ,
Detecting means for detecting an optical axis shift of the first beam and the second beam according to a difference between a timing at which the light receiving element receives the first beam and a timing at which the second beam is received;
Correction means for correcting the optical axis deviation of the first beam or the second beam based on the deviation detected by the detection means;
Have
The control means comprises the pattern drawn by the first beam and the second beam in the period of the one frame by a plurality of continuous scanning lines in the scanning region, and for each period of the one frame. A projection apparatus characterized in that the drawing position of the pattern is changed in the sub-scanning direction. A second beam irradiated from the first beam and the second light source is irradiated from the first light source, a scanning means for scanning along a scanning line to the scanning area at a predetermined frame rate,
A control method executed by a projection device that projects an image , comprising: a light receiving element disposed at a position capable of receiving the first beam and the second beam scanned in the scanning region;
A control step of changing a position at which the first beam and the second beam are irradiated in the scanning region with respect to the scanning region in a main scanning direction or a sub-scanning direction for each frame period;
A detection step of detecting a deviation of the optical axes of the first beam and the second beam according to a difference between a timing at which the light receiving element receives the first beam and a timing at which the second beam is received;
A correction step of correcting an optical axis shift of the first beam or the second beam based on the shift detected by the detection step;
Have
The control step sets a position at which the first beam and the second beam are applied to the scanning region in a period of the one frame to a plurality of continuous scanning lines in the scanning region, and the 1 A control method characterized by changing the irradiation position in the sub-scanning direction every frame period. A head-up display having an optical axis deviation correction device for correcting an optical axis deviation between the first beam emitted from the first light source and the second beam emitted from the second light source,
Scanning means for scanning the first beam and the second beam along a scanning line with respect to a scanning region at a predetermined frame rate;
A light receiving element disposed at a position capable of receiving the first beam and the second beam scanned in the scanning region;
Control means for changing the position at which the first beam and the second beam are irradiated in the scanning region in the main scanning direction or the sub-scanning direction for each frame period with respect to the scanning region;
Detecting means for detecting an optical axis shift of the first beam and the second beam according to a difference between a timing at which the light receiving element receives the first beam and a timing at which the second beam is received;
Correction means for correcting the optical axis deviation of the first beam or the second beam based on the deviation detected by the detection means;
Have
The control means sets a position at which the first beam and the second beam are applied to the scanning region in a period of the one frame to a plurality of continuous scanning lines in the scanning region, and the 1 A head-up display characterized in that its irradiation position is changed in the sub-scanning direction every frame period.

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