JP2016099561A - Projection device, projection method, program, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain display quality of an image while calibrating projected laser light by preventing generation of stray light when a laser is emitted during a blanking period.SOLUTION: A light beam emitted by light beam emission means is scanned over a scanning area by scanning means. The scanning area includes an imaging area for projecting an image and a non-imaging area. Control means controls the scanning means such that a light beam corresponding to an image is emitted while scanning the imaging area and a reference beam is emitted while scanning the non-imaging area. At least a portion of the reference beam is received by a photosensitive element which outputs a signal indicative of intensity of the received light to correction means. The correction means corrects the light beam emitted by the light beam emission means based on the signal from the photosensitive element. The control means changes the intensity of the reference beam in accordance with brightness of an image produced in the imaging area.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a technique for calibrating laser light projected by a projection apparatus.

  A projection device that displays an image by projecting light beams of a plurality of colors is known. For example, in Patent Document 1, in order to detect the deviation of the spot centers of light beams of a plurality of colors, a light beam is irradiated in a time zone (so-called blanking period) in which no image signal is input, A light beam scanning image projection apparatus that receives light and detects a positional shift of each color beam is disclosed.

  In Patent Document 2, in an image display device that projects an image by raster scanning a laser having a light amount based on an image signal emitted from a laser diode, image blanking is performed to calculate the temperature characteristics of the laser diode. In the period, there is disclosed a test output of a laser with different current values.

International Publication WO2009 / 154134 JP 2014-130256 A

  In each of the above-described conventional techniques, the laser beam emitted during the blanking period of the image is detected and monitored by the light receiving element, thereby calibrating the positional deviation and brightness of the beam.

  When the laser is emitted during the blanking period, it is generally considered to provide a light shielding mask that surrounds the image display area as an opening so that laser light emitted during the blanking period is not projected onto the projection surface. . However, in reality, stray light may appear to leak into the image display area due to tolerances in the dimensions of members such as optical components and light shielding masks and diffusion of unnecessary light by the optical elements.

  Examples of the problem to be solved by the present invention are as described above. The main object of the present invention is to calibrate the projected laser light while preventing stray light when the laser is emitted during the blanking period and maintaining the display quality of the image.

  The invention described in claim 1 is a projection device for projecting an image, and includes a light beam emitting means for emitting a light beam, and the light beam within a scanning region comprising a drawing region and a non-drawing region of the projected image. Scanning means that scans the drawing area, and the scanning means emits a light beam corresponding to the image while scanning the drawing area, and the scanning means emits a reference beam while scanning the non-drawing area. Based on the control means for controlling the beam emitting means, the light receiving element for receiving at least a part of the reference beam and outputting a signal relating to the intensity of the received light, the light output based on the signal output from the light receiving element Correction means for performing correction related to the light beam emitted by the beam emitting means, and the control means determines the reference beam according to the brightness of the image drawn in the drawing area. And wherein the changing the degrees.

  The invention described in claim is a projection method executed by a projection apparatus that includes a light beam emitting unit, a scanning unit, and a light receiving element, and projects an image, and the light beam is emitted by the light beam emitting unit. A light beam emitting step, a scanning step of scanning the light beam in a scanning region composed of a drawing region and a non-drawing region of the projected image by the scanning unit, and the scanning unit scanning the drawing region A control step of controlling the light beam emitting means to emit a light beam corresponding to the image, and causing the scanning means to emit a reference beam while scanning the non-drawing area, and A light receiving step for receiving at least a part of the beam and outputting a signal relating to the intensity of the received light, and the light beam emitting means based on the signal output from the light receiving element. And a correction step of performing correction on the light beam emitted from the light source, wherein the control step changes the intensity of the reference beam in accordance with the brightness of the image drawn in the drawing region. .

  The invention described in the claims is a program that is executed by a projection device that includes a light beam emitting unit, a scanning unit, a light receiving element, and a computer, and that projects an image. A scanning step of scanning the light beam in a scanning region composed of a drawing region and a non-drawing region of the image to be projected by the scanning unit, and the scanning unit scans the drawing region. A control step of controlling the light beam emitting means to emit a light beam corresponding to the image during scanning and causing the scanning means to emit a reference beam while scanning the non-drawing region; Based on a light receiving step of receiving at least a part of the reference beam and outputting a signal related to the intensity of the received light, and a signal output from the light receiving element, A correction step for performing correction on the light beam emitted by the light beam emitting means, and the control step performs the step of controlling the reference beam according to the brightness of the image drawn in the drawing area. It is characterized by changing the intensity.

1 shows a configuration of an image drawing apparatus according to a first embodiment. A mode that the laser beam which comprises an image is scanned is shown. A method for adjusting the intensity of light emission for calibration will be described. It is a flowchart of the intensity adjustment process of the light emission for calibration by 1st Example. The structure of the image drawing apparatus which concerns on 2nd Example is shown. It is a flowchart of the intensity | strength adjustment process of the light emission for calibration by 2nd Example. The structure of the image drawing apparatus which concerns on 3rd Example is shown.

  In a preferred embodiment of the present invention, the projection device for projecting an image includes a light beam emitting means for emitting a light beam, and the light beam within a scanning region composed of a drawing region and a non-drawing region of the projected image. Scanning means for scanning; and the light beam so that the scanning means emits a light beam corresponding to the image while scanning the drawing area, and the scanning means emits a reference beam while scanning the non-drawing area. Based on a control means for controlling the emission means, a light receiving element that receives at least a part of the reference beam and outputs a signal relating to the intensity of the received light, and the light beam based on the signal output from the light receiving element Correction means for performing correction related to the light beam emitted by the emission means, and the control means determines the reference beam according to the brightness of the image drawn in the drawing area. Changing the degree.

  According to the above projection apparatus, the light beam emitted from the light beam emitting means is scanned in the scanning region by the scanning means. The scanning area includes a drawing area and a non-drawing area of an image to be projected. The control unit controls the scanning unit to emit a light beam corresponding to the image while scanning the drawing area, and to emit a reference beam while scanning the non-drawing area. At least a part of the reference beam is received by the light receiving element, and a signal related to the intensity of the received light is output to the correction means. The correcting means corrects the light beam emitted by the light beam emitting means based on the signal from the light receiving element. The control means changes the intensity of the reference beam according to the brightness of the image drawn in the drawing area. Thereby, the influence of the light leakage of a light beam can be suppressed.

  In one aspect of the above projection apparatus, the control unit stops the emission of the reference beam when the brightness of the image drawn in the drawing area is darker than a predetermined brightness. In this aspect, when the image to be drawn is dark, light leakage is conspicuous, so the emission of the reference beam is stopped to prevent the influence of light leakage.

  In a preferred aspect of this case, the image processing apparatus includes detection means for detecting the brightness of the external environment, and the control means is configured to detect the reference when the brightness of the external environment detected by the detection means is brighter than a reference brightness. Do not stop the beam injection. In this aspect, light leakage is not noticeable when the external environment is bright, and the reference beam emission is stopped only when the external environment is dark. Thus, correction by the correction unit is performed without stopping the emission of the reference beam as much as possible.

  In another aspect of the projection apparatus, the control unit emits the reference beam at a first intensity when the brightness of the image drawn in the drawing area is equal to or higher than a predetermined brightness, When the brightness of the image drawn in the drawing area is darker than the predetermined brightness, the reference beam is emitted at a second intensity that is weaker than the first intensity. In this aspect, light leakage is conspicuous when the drawn image is dark. Therefore, the influence of light leakage is suppressed by reducing the intensity of the reference beam.

  A preferable aspect in this case includes a detection unit that detects the brightness of the external environment, and the control unit detects the reference when the brightness of the external environment detected by the detection unit is brighter than a reference brightness. The intensity of the beam is maintained at the first intensity. In this aspect, light leakage is not noticeable when the external environment is bright, and therefore the intensity of the reference beam is reduced only when the external environment is dark.

  In another preferred embodiment of the present invention, a projection method that includes a light beam emitting unit, a scanning unit, and a light receiving element and that is executed by a projection apparatus that projects an image includes a light beam emitted from the light beam emitting unit. A light beam emitting step of emitting; a scanning step of scanning the light beam within a scanning region composed of a drawing region and a non-drawing region of the projected image by the scanning unit; and the scanning unit scanning the drawing region. A control step of controlling the light beam emitting means so that the light beam corresponding to the image is emitted, and the scanning means emits a reference beam while scanning the non-drawing region, and the light receiving element A light receiving step of receiving at least a part of the reference beam and outputting a signal related to the intensity of the received light; and the light beam emission based on the signal output from the light receiving element. Comprising a correction step of performing correction for the light beam means is emitted, the said control process, in accordance with the brightness of the image to be drawn in the drawing area, varying the intensity of said reference beam. Also by this projection method, the influence of light leakage of the light beam can be suppressed by changing the intensity of the reference beam according to the brightness of the image drawn in the drawing area.

  In another preferred embodiment of the present invention, a program executed by a projection apparatus that includes a light beam emitting unit, a scanning unit, a light receiving element, and a computer and that projects an image is transmitted by the light beam emitting unit. A light beam emitting step of emitting a beam, a scanning step of scanning the light beam in a scanning region composed of a drawing region and a non-drawing region of the projected image by the scanning unit, and the scanning unit includes the drawing region. A control step of controlling the light beam emitting means to emit a light beam corresponding to the image during scanning, and the scanning means to emit a reference beam while scanning the non-drawing area; A light receiving step of receiving at least a part of the reference beam and outputting a signal related to the intensity of the received light; and a signal output from the light receiving element. And a correction step for performing correction on the light beam emitted by the light beam emitting means, and the control step performs the reference beam according to the brightness of the image drawn in the drawing area. Vary the intensity. By executing this program, the influence of the light leakage of the light beam can be suppressed by changing the intensity of the reference beam according to the brightness of the image drawn in the drawing area. This program can be stored and handled in a storage medium.

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

[First embodiment]
(Configuration of image drawing device)
FIG. 1 shows a configuration of an image drawing apparatus 1 to which the projection apparatus according to the first embodiment 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 an optical system 10. 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 95, and is an ASIC (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.

  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 driving circuit 71 drives the red laser LD1 based on the signal output from the light emission pattern conversion unit 33. The blue laser drive circuit 72 drives the blue laser LD2 based on the signal output from the light emission pattern conversion unit 33. The green laser drive 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 95 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 95 based on a signal from the timing controller. The driver circuit 82 amplifies the control signal of the MEMS mirror 95 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, and reflection mirrors 92a to 92c.

  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, respectively. The reflection mirror 92b reflects the blue laser light Lb. 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 lights Lb and Lg reflected by the reflection mirror 92 a are incident on the MEMS mirror 95.

  At a position where laser light is emitted from the laser light source unit 9, a light shielding mask 11, an optical element 12, a microlens array 13, and a field lens 14 are provided as an optical system 10 for displaying an image. Yes.

  The MEMS mirror 95 reflects the laser light incident from the reflection mirror 92a toward the microlens array 13 which is an example of EPE (Exit Pupil Expander). The MEMS mirror 95 basically displays the image input to the image signal input unit 2 (hereinafter referred to as “input image”) under the control of the MEMS control unit 8. The scanning position information (for example, information such as the angle of the mirror) at that time is output to the video ASIC 3 as scanning position information Sc.

  The microlens array 13 has a plurality of microlenses arranged thereon, and the laser beam reflected by the MEMS mirror 95 is incident thereon. The field lens 14 enlarges an image formed on the radiation surface of the microlens array 13 and projects it on a projection surface (not shown). For example, when the image drawing apparatus 1 is used as a light source for a head-up display, the field lens 14 emits light constituting a display image to a combiner or the like.

  FIG. 2A shows the optical system 10 viewed from the MEMS mirror 95 side (in the direction of arrow Z in FIG. 1). A light shielding mask 11 is provided at a position closest to the laser light source unit 9 in the optical system 10. A microlens array 13 and a field lens 14 are provided behind the light shielding mask 11. The light-shielding mask 11 covers the scannable region of the laser beam by the MEMS mirror 95, and an opening 11x is provided at substantially the center. The opening 11x corresponds to the position of the microlens array 13 and the field lens 14 provided behind, and corresponds to the image display area 15 for displaying an input image. The light shielding mask 11 is preferably composed of a black member in order to reduce stray light generated by reflection of light constituting the image.

  The laser light of each color is scanned by the MEMS mirror 95 according to the scanning line 16 shown in the figure. Of the laser light scanned along the scanning line 16, only the laser light that has passed through the opening 11 x enters the microlens array 13. To reach.

  An optical element 12 is provided above the opening 11x of the light shielding mask 11. The optical element 12 is for performing calibration for adjusting the intensity of the laser beam. The optical element 12 is in a scannable region where the laser beam is scanned by the MEMS mirror 95 and in an area outside the image display region 15 (hereinafter, “ This is called a “blanking area”. In this embodiment, the optical element 12 is provided above the opening 11x as shown in FIG. 2A, but the optical element 12 may be provided anywhere within the blanking region. The light receiving element 12 outputs a detection signal Sd indicating the amount of incident laser light to the video ASIC 3.

  In the above configuration, the laser light source unit 9 is an example of the light beam emitting unit of the present invention, the MEMS mirror 95 is an example of the scanning unit of the present invention, and the video ASIC 3 is the control unit and the correcting unit of the present invention. It is an example.

  Next, display control by the video ASIC 3 will be described. The video ASIC 3 outputs a light emission intensity signal for designating the light emission intensity to the laser driver ASIC 7 based on the input image input to the image signal input unit 2. The laser driver ASIC 7 controls the laser drive circuits 71 to 73 in accordance with the emission intensity signal, and changes the current for driving the lasers LD1 to LD3. Further, the video ASIC 3 outputs a timing signal to the MEMS control unit 8 so as to scan the laser light within the image display area 15 according to the input image. Thus, the laser beam corresponding to the input image is scanned in the image display area 15.

  Further, the video ASIC 3 outputs to the laser driver ASIC 7 a light emission intensity signal designating a preset light emission intensity so that the calibration laser light is incident on the light receiving element 12 in the blanking region. Note that laser light emission for calibration is referred to as “calibration light emission”. Note that the calibration light emission may emit RGB laser light for each color, or may emit multiple colors of laser light simultaneously. The light emission for calibration only needs to be performed when the laser beam scanned by the MEMS mirror 95 passes through the optical element 12, and is a period of one scanning line in the main scanning direction (X direction) of the MEMS mirror 95. It may be performed, or may be performed for a period shorter than one scanning line as long as the laser light is surely incident on the optical element 12. For example, calibration light emission may be performed only during a period in which the laser light is scanned on the optical element 12, or the laser light may be emitted in a spot shape at a timing when the laser light is on the optical element 12.

  The light receiving element 12 outputs to the video ASIC 3 a detection signal Sd corresponding to the amount of laser light incident by the calibration light emission. The video ASIC 3 acquires the detection signal Sd, detects a difference from a reference value (hereinafter referred to as “calibration reference value”), and corrects the emission intensity signal so that the difference is reduced. The calibration reference value is a value indicating a desired light emission intensity that is set in consideration of the temperature characteristics of the laser element, aging, and the like.

  In this way, the video ASIC 3 uses the blanking area to emit light for calibration, so that the amount of laser light can be monitored even when the image drawing apparatus 1 is in use. It is possible to correct the change in the light amount due to the change and the temperature characteristic, and always display an image with a desired brightness.

  In the present embodiment, the light shielding mask 11 is provided on the front side of the microlens array 13 as described above. However, even if the light shielding mask 11 is provided, diffusion by an optical member existing on the optical path of the laser light, etc. Light leakage may occur due to the stray light. This light leakage is inconspicuous when the displayed image is bright, but becomes conspicuous when the image is dark, particularly when the image displayed when used at night in a vehicle is dark.

  Therefore, in this embodiment, as a first method, the calibration light emission is stopped according to the brightness of the input image. Specifically, the video ASIC 3 calculates the average brightness of the image from the data of the input image to the image signal input unit 2, and if the average brightness is equal to or lower than the predetermined brightness, calibration is performed. Stops flashing. Thereby, it is possible to prevent the user from recognizing light leakage caused by light due to light emission for calibration. Note that the brightness of the image can be calculated based on, for example, the luminance signal of the image data and the level of the RGB signal.

  Further, as a second method, the intensity of the calibration light emission may be changed instead of stopping the calibration light emission. Specifically, the video ASIC 3 calculates the average brightness of the image from the data of the input image input to the image signal input unit 2, and when the average brightness is equal to or lower than the predetermined brightness. Reduce the intensity of light emission for calibration. As the intensity of light emission for calibration, a plurality of intensities are set in advance according to the average brightness of the input image. The preset light emission intensity becomes weaker as the average brightness of the input image is darker. The video ASIC 3 performs calibration light emission at a light emission intensity corresponding to the calculated average brightness. According to this method, when the input image is dark, the intensity of calibration light emission becomes weak, so that even if light leakage occurs, it can be made inconspicuous.

  In the following description, it is expressed as “adjusting the intensity of the calibration light emission” including both stopping the light emission for calibration and reducing the light emission intensity of the light emission for calibration. To do.

  FIG. 3 schematically shows how the intensity of light emission for calibration is changed according to the average brightness of the input image. 3A and 3B, the thickness of the arrow 16 indicates the emission intensity, and the thicker the arrow 16, the higher the emission intensity.

  FIG. 3A shows a case where the input image is bright. As indicated by the arrow 16, the intensity of light emission for calibration passing over the optical element 12 is strong, but since the input image is a bright image, it is not so noticeable even if some light leakage occurs. FIG. 3B shows a case where the input image is dark. Since the input image is a dark image, it becomes noticeable even with a slight amount of light leakage. Therefore, the intensity of light emission for calibration is reduced to make the light leakage less noticeable. In this way, if the intensity of the calibration light emission is adjusted according to the average brightness of the input image, the calibration light emission can be performed even if the input image is a dark image, and the brightness of the image is always maintained. Can be corrected.

  In the above example, the target area (hereinafter referred to as “brightness monitoring area”) when calculating the average brightness of the input image is the entire input image, but instead, a part of the input image is used. Only the brightness monitoring area may be used. That is, the average brightness of only a part of the input image may be calculated, and the intensity of light emission for calibration may be adjusted based on the average brightness.

  When the brightness monitoring area is a part of the input image, the brightness monitoring area is preferably set to an area close to the optical element 12. For example, as shown in FIG. 2B, when the optical element 12 is located above the image display area 15, the brightness monitoring area 17 is set above the image display area 15. This is because the brightness of the image in the region close to the region where the calibration light emission is performed greatly affects the conspicuousness of light leakage. Therefore, unlike FIG. 2B, for example, when the optical element 12 is positioned below the image display area 15, a part of the lower side of the image display area 15 may be set as the brightness monitoring area. .

  In the example of FIG. 2B, the brightness monitoring area is a half of the input image, but this is only an example. The size of the brightness monitoring area may be set as appropriate according to the influence of light leakage from the calibration light emission. That is, the brightness monitoring area may be the entire image display area 15 or may be an arbitrary ratio such as 3/4 or 1/2 according to the influence of light leakage.

  FIG. 4 is a flowchart of calibration light emission intensity adjustment processing. This process is mainly performed by the video ASIC 3 and adjusts the intensity of light emission for calibration. This process includes both the case where the light emission for calibration is stopped and the case where the light emission intensity is lowered.

  First, the video AISC 3 calculates the average brightness of the input image based on the input image data input from the image signal input unit 2 (step S1). Note that the brightness monitoring area at this time is set to the whole or a part of the image display area 15 as necessary as described above.

  Next, the video ASIC 3 determines whether or not the calculated average brightness of the input image is darker than a predetermined brightness set in advance (step S2). When the average brightness of the input image is not darker than the predetermined brightness (step S2: No), the video ASIC 3 sets the intensity of light emission for calibration to the reference intensity (step S4). Then, the process proceeds to step S5.

  On the other hand, when the average brightness of the input image is darker than the predetermined brightness (step S2: Yes), the video ASIC 3 stops the light emission for calibration or sets the intensity of the light emission for calibration as described above. Decrease (step S3). Then, the process proceeds to step S5.

  In step S5, the video ASIC 3 determines whether or not the input image is finished, that is, whether or not the input of the image to the image signal input unit 2 is stopped (step S5). If the input image has not ended (step S5: No), the process returns to step S1. Thus, even if the input image changes, the intensity of light emission for calibration is adjusted according to the average brightness of the input image. On the other hand, when the input image ends (step S5: Yes), the process ends.

  As described above, in the first embodiment, the intensity of light emission for calibration is adjusted according to the average brightness of the input image, so that light leakage of light emission for calibration can be made inconspicuous.

[Second Embodiment]
As described above, the light leakage caused by the calibration light emission is not noticeable when the input image is bright. Therefore, for example, when the image drawing apparatus of the embodiment is applied to a head-up display mounted on a vehicle, light leakage is less noticeable in a bright external environment such as daytime. Therefore, in the second embodiment, a sensor for detecting the brightness of the external environment is provided, and for calibration only according to the brightness of the input image as in the first embodiment, only when the external environment is dark, such as at night. Control to adjust the intensity of light emission is performed.

  FIG. 5 shows a configuration of an image drawing apparatus 1a according to the second embodiment. The image drawing apparatus 1a is configured in the same manner as the image drawing apparatus 1 shown in FIG. 1 except that an optical sensor 19 that detects the brightness of the external environment is provided. The optical sensor 19 detects the amount of external light and outputs a detection signal to the video ASIC 3. The optical sensor 19 is an example of the detection means of the present invention.

  The video ASIC 3 is used for calibration according to the brightness of the input image, as in the first embodiment, when the external environment is dark, that is, when the external light amount indicated by the detection signal from the optical sensor 19 is not more than a predetermined value. A process for adjusting the intensity of light emission is performed. On the other hand, when the external environment is bright, that is, when the external light quantity is a predetermined value or more, the process of adjusting the intensity of light emission for calibration is not performed.

  FIG. 6 is a flowchart of calibration light emission intensity adjustment processing according to the second embodiment. This process is mainly performed by the video ASIC 3.

  First, the video ASIC 3 detects the external light quantity based on the detection signal from the optical sensor 19 (step S11). If the external light amount is smaller than the predetermined threshold, that is, if the external environment is dark (step S12: Yes), the process proceeds to step S13. Steps S13 to S15 are the same as steps S1 to S3 of the first embodiment, and the intensity of light emission for calibration is adjusted according to the average brightness of the input image. Then, the process proceeds to step S17.

  On the other hand, when the external light amount is larger than the predetermined threshold, that is, when the external environment is bright (No at Step S11), the video ASIC 3 sets the intensity of light emission for calibration to the reference intensity (Step S16). Then, the process proceeds to step S17.

  In step S17, the video ASIC 3 determines whether or not the input image has been completed. If the input image has not ended (step S17: No), the process returns to step S11. On the other hand, when the input image ends (step S17: Yes), the process ends.

  As described above, in the second embodiment, processing for adjusting the intensity of light emission for calibration is performed only when the external environment is dark. As a result, when the external environment is bright, it is possible to always perform calibration light emission at the reference intensity to correct the brightness of the image.

[Third embodiment]
In the first and second embodiments, the light receiving element 12 is provided at the position of the light shielding mask 11. Instead, in the third embodiment, the light receiving element 12x is provided at a position in front of the MEMS mirror 95.

  FIG. 7 shows a configuration of an image drawing apparatus 1b according to the third embodiment. As can be seen from comparison with FIG. 1, the image drawing apparatus 1 b according to the third embodiment is the first embodiment except that the light receiving element 12 x is provided in the laser light source unit 9 at a position in front of the MEMS mirror 95. It has the same configuration as the image drawing apparatus 1 of the example. The light receiving element 12x has the same function as the light receiving element 12 of the first embodiment, and outputs a detection signal Sd indicating the amount of incident laser light to the video ASIC 3. Similar to the first embodiment, the video ASIC 3 adjusts the intensity of light emission for calibration according to the brightness of the input image.

  Also in the third embodiment, since light emission for calibration is performed during the period in which the MEMS mirror 95 scans the blanking region, a problem of light leakage may occur. However, in the first and second embodiments, the laser beam scanned by the MEMS mirror 95, that is, the scanning beam is incident on the optical element 12, whereas in the third embodiment, the laser beam before being scanned by the MEMS mirror 95 is used. The laser light is directly, that is, more reliably incident on the optical element 12x. Therefore, since the light emission time for performing the calibration light emission can be shortened as compared with the first and second embodiments, the influence can be reduced even if light leakage occurs. As a result, the reference value of the brightness of the image used when determining whether or not to adjust the intensity of light emission for calibration (“predetermined brightness” in step S2 in FIG. 4 and step S14 in FIG. 6). Can be lowered. As a result, the frequency with which the intensity of calibration light emission is adjusted decreases, and the probability that calibration light emission is performed at the reference intensity increases.

  The second embodiment may be combined with the third embodiment. That is, in the image drawing apparatus 1b of the third embodiment shown in FIG. 7, an optical sensor 19 is further provided as in the second embodiment, and the intensity of calibration light emission is adjusted by the same method as in the second embodiment. Also good.

[Modification]
In the above embodiment, the brightness of the image is corrected by light emission for calibration, but the application of the present invention is not limited to this. For example, the present invention may be applied to correction of color deviation or position deviation (color balance) of laser light by light emission for calibration in the blanking region.

1, 1a, 1b Image drawing device 3 Video ASIC
7 Laser driver ASIC
8 MEMS Control Unit 10 Optical System 11 Shading Mask 12, 12x Optical Element 13 Micro Lens Array 14 Field Lens 95 MEMS Mirror

Claims (8)

A projection device for projecting an image,
A light beam emitting means for emitting a light beam;
Scanning means for scanning the light beam in a scanning region composed of a drawing region and a non-drawing region of the image to be projected;
Control for controlling the light beam emitting means so that the scanning means emits a light beam corresponding to the image while scanning the drawing area, and the scanning means emits a reference beam while scanning the non-drawing area. Means,
A light receiving element that receives at least part of the reference beam and outputs a signal related to the intensity of the received light;
Correction means for correcting the light beam emitted by the light beam emission means based on the signal output from the light receiving element;
With
The projection device characterized in that the control means changes the intensity of the reference beam in accordance with the brightness of the image drawn in the drawing area.   The projection apparatus according to claim 1, wherein the control unit stops the emission of the reference beam when the brightness of the image drawn in the drawing area is darker than a predetermined brightness. Equipped with detection means for detecting the brightness of the external environment,
The projection apparatus according to claim 2, wherein the control unit does not stop the emission of the reference beam when the brightness of the external environment detected by the detection unit is brighter than the reference brightness.   The control means emits the reference beam at a first intensity when the brightness of the image drawn in the drawing area is equal to or higher than a predetermined brightness, and the brightness of the image drawn in the drawing area 2. The projection apparatus according to claim 1, wherein when the height is darker than the predetermined brightness, the reference beam is emitted at a second intensity that is weaker than the first intensity. Equipped with detection means for detecting the brightness of the external environment,
5. The control unit according to claim 4, wherein when the brightness of the external environment detected by the detection unit is brighter than a reference brightness, the intensity of the reference beam is maintained at the first intensity. The projection apparatus described in 1. A projection method that includes a light beam emitting unit, a scanning unit, and a light receiving element, and that is executed by a projection device that projects an image,
A light beam emitting step of emitting a light beam by the light beam emitting means;
A scanning step of scanning the light beam in a scanning region composed of a drawing region and a non-drawing region of the image to be projected by the scanning unit;
Control for controlling the light beam emitting means so that the scanning means emits a light beam corresponding to the image while scanning the drawing area, and the scanning means emits a reference beam while scanning the non-drawing area. Process,
A light receiving step of receiving at least a part of the reference beam by the light receiving element and outputting a signal related to the intensity of the received light;
A correcting step for correcting the light beam emitted by the light beam emitting means based on the signal output from the light receiving element;
With
The projection method characterized in that the control step changes the intensity of the reference beam in accordance with the brightness of the image drawn in the drawing area. A program that includes a light beam emitting unit, a scanning unit, a light receiving element, and a computer and that is executed by a projection device that projects an image,
A light beam emitting step of emitting a light beam by the light beam emitting means;
A scanning step of scanning the light beam in a scanning region composed of a drawing region and a non-drawing region of the image to be projected by the scanning unit;
Control for controlling the light beam emitting means so that the scanning means emits a light beam corresponding to the image while scanning the drawing area, and the scanning means emits a reference beam while scanning the non-drawing area. Process,
A light receiving step of receiving at least a part of the reference beam by the light receiving element and outputting a signal related to the intensity of the received light;
A correcting step for correcting the light beam emitted by the light beam emitting means based on the signal output from the light receiving element;
To the computer,
The control step includes changing the intensity of the reference beam according to the brightness of the image drawn in the drawing area.   A storage medium storing the program according to claim 7.