JP2016127543A - Projection apparatus, projection method, program, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection apparatus capable of detecting a failure in an early stage regardless of lightness of an image to be drawn.SOLUTION: In the projection apparatus, a light source emits light constituting an image. Light receiving means receives a part of the light emitted from the light source and outputs an output value corresponding to the quantity of the light. On the basis of the lightness of the image, setting means sets a first reference value corresponding to an allowable upper limit value for an intensity of the light emitted by the light source and a second reference value corresponding to an allowable lower limit value for an intensity of the light emitted by the light source. Control means stops emission of the light by the light source when the output value output by the receiving means exceeds the first reference value that is set by the setting means or when the output value output by the receiving means is lower than the second reference value that is set by the setting means.SELECTED DRAWING: Figure 3

Description

  The present invention relates to output control of laser light projected by a projection device.

  Projection devices such as in-vehicle head-up displays are expected to increase the brightness of images projected on the projection surface, but from the viewpoint of protecting the eyes of the observer, of course, It is necessary to prevent an excessive amount of light from being emitted in the event of any failure of the projection apparatus.

  For example, Patent Literature 1 discloses a technique for preventing excessive light emission of a laser light emitting element. The laser drawing apparatus described in Patent Document 1 includes a laser level detection circuit that detects whether or not the detection output of a photodetector that detects the laser output of a laser light emitting element is outside an allowable range. When the laser level detection circuit detects that the detection output of the photodetector is outside the allowable range, the automatic power control circuit of the laser light emitting element drives the laser light emitting element drive signal to reduce or stop the laser output in preference to the control signal. To control. This prevents excessive light emission of the laser light emitting element, thereby preventing danger to the human body and damage to the drawing surface due to excessive light emission.

JP-A-3-15887

  In the method of Patent Document 1, when the automatic power control circuit or the laser light emitting element fails and the laser output becomes a safe value or more, the detection output of the photodetector is out of the allowable range, so that the laser output is reduced or stopped. However, if the image to be drawn is dark, the laser output under normal conditions is weak, so it is possible that the detection output of the photodetector will fall within the allowable range even if some kind of failure occurs. May have been delayed.

  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 a projection device capable of detecting a failure at an early stage regardless of the brightness of an image to be drawn.

  The invention described in the claims is a projection device that projects an image, and controls a light source that emits light constituting the image and an intensity of light emitted by the light source based on an image signal indicating the image. Control means; setting means for setting a first reference value corresponding to an allowable upper limit value of the intensity of light emitted from the light source based on brightness of an image indicated by the image signal; and Light receiving means for receiving a part of light and outputting an output value corresponding to the received light quantity, wherein the control means is a first reference value in which an output value output by the light receiving means is set by the setting means. The emission of light by the light source is stopped when exceeding.

  The invention described in the claims is a projection device that projects an image, and controls a light source that emits light constituting the image and an intensity of light emitted by the light source based on an image signal indicating the image. Control means; setting means for setting a second reference value corresponding to an allowable lower limit value of the intensity of light emitted from the light source based on brightness of the image indicated by the image signal; and Light receiving means for receiving a part of light and outputting an output value corresponding to the received light quantity, and the control means is a second reference value in which the output value output by the light receiving means is set by the setting means. In the case where it is less than the above, emission of light by the light source is stopped.

  The invention described in claim includes a light source that emits light constituting an image, and a light receiving unit that receives a part of the light emitted from the light source and outputs an output value corresponding to the received light amount. A projection method executed by a projection apparatus, the control step of controlling the intensity of light emitted from the light source based on an image signal indicating the image, and the brightness of the image indicated by the image signal, A setting step for setting a first reference value corresponding to an allowable upper limit value of the intensity of light emitted from the light source, and in the control step, an output value output from the light receiving means is set by the setting step. When the first reference value is exceeded, the light emission by the light source is stopped.

  The invention described in claim includes a light source that emits light constituting an image, and a light receiving unit that receives a part of the light emitted from the light source and outputs an output value corresponding to the received light amount. A projection method executed by a projection apparatus, the control step of controlling the intensity of light emitted from the light source based on an image signal indicating the image, and the brightness of the image indicated by the image signal, A setting step for setting a second reference value corresponding to an allowable lower limit value of the intensity of light emitted from the light source, and in the control step, an output value output from the light receiving means is set by the setting step. When the second reference value is not satisfied, the light emission by the light source is stopped.

  The invention described in the claims includes a light source that emits light constituting an image, a light receiving unit that receives a part of the light emitted by the light source, and outputs an output value corresponding to the received light amount, a computer, A control step for controlling the intensity of light emitted by the light source based on an image signal indicating the image, based on the brightness of the image indicated by the image signal, A setting step of setting a first reference value corresponding to an allowable upper limit value of the intensity of light emitted from the light source, causing the computer to execute an output value output from the light receiving means according to the setting step; The light emission by the light source is stopped when the set first reference value is exceeded.

  The invention described in the claims includes a light source that emits light constituting an image, a light receiving unit that receives a part of the light emitted by the light source, and outputs an output value corresponding to the received light amount, a computer, A control step for controlling the intensity of light emitted by the light source based on an image signal indicating the image, based on the brightness of the image indicated by the image signal, A setting step of setting a second reference value corresponding to an allowable lower limit value of the intensity of light emitted from the light source, and causing the computer to execute an output value output from the light receiving means according to the setting step. When the set second reference value is not satisfied, light emission by the light source is stopped.

  The invention described in the claims is a projection device that projects an image, and controls a light source that emits light constituting the image and an intensity of light emitted by the light source based on an image signal indicating the image. Based on the brightness of the image indicated by the control signal and the image signal, a first reference value corresponding to an allowable upper limit value of the intensity of light emitted from the light source, and an allowable lower limit value of the intensity of light emitted from the light source Setting means for setting a second reference value corresponding to the value; and light receiving means for receiving a part of the light emitted from the light source and outputting an output value corresponding to the received light quantity, and the control means When the output value output by the light receiving unit exceeds the first reference value set by the setting unit or when the output value does not satisfy the second reference value set by the setting unit, Special feature to stop light emission To.

It is a block diagram which shows the structure of the projection apparatus which concerns on 1st Example. It is a graph which shows the function data memorize | stored in a non-volatile memory. It is a flowchart of the light emission stop process which concerns on 1st Example. It is a block diagram which shows the structure of the projection apparatus which concerns on 2nd Example. It is a flowchart of the light emission stop process which concerns on 2nd Example.

  In a preferred embodiment of the present invention, a projection device that projects an image has a light source that emits light constituting the image, and a control that controls the intensity of the light emitted by the light source based on an image signal indicating the image. Means for setting a first reference value corresponding to an allowable upper limit value of the intensity of light emitted from the light source based on the brightness of the image indicated by the image signal, and one of lights emitted from the light source. And a light receiving means for outputting an output value corresponding to the received light quantity, and the control means outputs the first reference value set by the setting means as the output value output by the light receiving means. When exceeding, the light emission by the light source is stopped.

  In the above projection device, the light source emits light constituting the image. The light receiving means receives a part of the light emitted from the light source and outputs an output value corresponding to the light quantity. The setting means sets a first reference value corresponding to an allowable upper limit value of the intensity of light emitted from the light source based on the brightness of the image. The control means stops light emission by the light source when the output value output from the light receiving means exceeds the first reference value.

  Thereby, the emission of light is stopped when an abnormality occurs in the light source or the light receiving means. Further, since the first reference value is set to an appropriate value based on the brightness of the image, it is possible to detect an abnormality of the apparatus at an early stage without being affected by the brightness of the image.

  In one aspect of the above projection apparatus, the setting unit sets the first reference value based on an integrated value of brightness of a predetermined section in the image signal, and the control unit receives the light reception during the predetermined period. When the integrated value of the output values output by the means exceeds the first reference value, the light emission by the light source is stopped. In this aspect, since the first reference value is set based on the brightness of a predetermined section in the image signal, it is possible to remove influences such as instantaneous noise due to some reason.

  In another aspect of the above projection apparatus, the light source includes a plurality of light emitting elements that emit the respective three primary colors, and the setting unit includes each of the three primary colors of the image indicated by the image signal. A first reference value corresponding to an allowable upper limit value of the combined light intensity of the light emitted by the plurality of light emitting elements is set based on the brightness of each of the light emitting elements, and the light receiving unit is configured to output the combined light emitted by the light source. A part of the light is received. In this aspect, all of the plurality of light emitting elements can be stopped based on the intensity of the combined light.

  In another preferred embodiment of the present invention, a projection device that projects an image controls a light source that emits light constituting the image and an intensity of the light emitted by the light source based on an image signal indicating the image. Control means for setting, setting means for setting a second reference value corresponding to an allowable lower limit value of the intensity of light emitted from the light source based on the brightness of the image indicated by the image signal, and light emitted by the light source Light receiving means for receiving a part of the light and outputting an output value corresponding to the received light quantity, wherein the control means is a second reference in which the output value output by the light receiving means is set by the setting means. When the value is not satisfied, the light emission by the light source is stopped.

  In the above projection device, the light source emits light constituting the image. The light receiving means receives a part of the light emitted from the light source and outputs an output value corresponding to the light quantity. The setting means sets a second reference value corresponding to the allowable lower limit value of the intensity of light emitted from the light source based on the brightness of the image. The control means stops light emission by the light source when the output value output from the light receiving means is less than the second reference value.

  Thereby, the emission of light is stopped when an abnormality occurs in the light source or the light receiving means. In addition, since the second reference value is set to an appropriate value based on the brightness of the image, it is possible to detect an abnormality of the apparatus at an early stage without being affected by the brightness of the image.

  In one aspect of the above projection apparatus, the setting unit sets the second reference value based on an integrated value of brightness of a predetermined section in the image signal, and the control unit receives the light reception during the predetermined period. When the integrated value of the output values output by the means is less than the second reference value, the light emission by the light source is stopped. In this aspect, since the second reference value is set based on the brightness of a predetermined section in the image signal, it is possible to remove the influence of instantaneous noise or the like for some reason.

  In another aspect of the above projection apparatus, the light source includes a plurality of light emitting elements that emit the respective three primary colors, and the setting unit includes each of the three primary colors of the image indicated by the image signal. A second reference value corresponding to an allowable lower limit of the intensity of the combined light of the light emitted from the plurality of light emitting elements is set based on the brightness of each light, and the light receiving unit is configured to output the combined light emitted from the light source. A part of the light is received. In this aspect, all of the plurality of light emitting elements can be stopped based on the intensity of the combined light.

  In another preferred embodiment of the present invention, a light source that emits light constituting an image, and a light receiving unit that receives a part of the light emitted from the light source and outputs an output value corresponding to the received light amount. The projection method executed by the projection device includes: a control step of controlling the intensity of light emitted from the light source based on an image signal indicating the image; and a brightness of the image indicated by the image signal. A setting step of setting a first reference value corresponding to an allowable upper limit value of the intensity of light emitted from the light source, and in the control step, an output value output from the light receiving means is set by the setting step. If the first reference value is exceeded, light emission by the light source is stopped.

  This method also stops the emission of light when an abnormality occurs in the light source or the light receiving means. Further, since the first reference value is set to an appropriate value based on the brightness of the image, it is possible to detect an abnormality of the apparatus at an early stage without being affected by the brightness of the image.

  In another preferred embodiment of the present invention, a light source that emits light constituting an image, and a light receiving unit that receives a part of the light emitted from the light source and outputs an output value corresponding to the received light amount. The projection method executed by the projection device includes: a control step of controlling the intensity of light emitted from the light source based on an image signal indicating the image; and a brightness of the image indicated by the image signal. A setting step for setting a second reference value corresponding to an allowable lower limit value of the intensity of light emitted from the light source, and in the control step, an output value output from the light receiving means is set by the setting step. If the second reference value is not satisfied, the light emission by the light source is stopped.

  This method also stops the emission of light when an abnormality occurs in the light source or the light receiving means. In addition, since the second reference value is set to an appropriate value based on the brightness of the image, it is possible to detect an abnormality of the apparatus at an early stage without being affected by the brightness of the image.

  In another preferred embodiment of the present invention, a light source that emits light constituting an image, and a light receiving unit that receives a part of the light emitted from the light source and outputs an output value corresponding to the received light amount. And a computer program executed by a projection device comprising: a control step of controlling intensity of light emitted from the light source based on an image signal indicating the image; and a brightness of an image indicated by the image signal. A setting step of setting a first reference value corresponding to an allowable upper limit value of the intensity of light emitted from the light source, and causing the computer to execute an output value output from the light receiving means in the setting step. When the first reference value set by (1) is exceeded, the light emission by the light source is stopped.

  By executing this program, light emission is stopped when an abnormality occurs in the light source or the light receiving means. Further, since the first reference value is set to an appropriate value based on the brightness of the image, it is possible to detect an abnormality of the apparatus at an early stage without being affected by the brightness of the image.

  In another preferred embodiment of the present invention, a light source that emits light constituting an image, and a light receiving unit that receives a part of the light emitted from the light source and outputs an output value corresponding to the received light amount. And a computer program executed by a projection device comprising: a control step of controlling intensity of light emitted from the light source based on an image signal indicating the image; and a brightness of an image indicated by the image signal. A setting step of setting a second reference value corresponding to an allowable lower limit value of the intensity of light emitted from the light source, and causing the computer to execute an output value output from the light receiving means in the setting step. When the second reference value set by (2) is not satisfied, the light emission by the light source is stopped.

  By executing this program, light emission is stopped when an abnormality occurs in the light source or the light receiving means. In addition, since the second reference value is set to an appropriate value based on the brightness of the image, it is possible to detect an abnormality of the apparatus at an early stage without being affected by the brightness of the image.

  In another preferred embodiment of the present invention, a projection device that projects an image controls a light source that emits light constituting the image and an intensity of the light emitted by the light source based on an image signal indicating the image. And a first reference value corresponding to an allowable upper limit value of the intensity of light emitted from the light source based on brightness of an image indicated by the image signal, and an allowable intensity of light emitted from the light source. A setting means for setting a second reference value corresponding to a lower limit value; and a light receiving means for receiving a part of the light emitted from the light source and outputting an output value corresponding to the received light quantity. When the output value output from the light receiving unit exceeds the first reference value set by the setting unit, or when the output value is less than the second reference value set by the setting unit, the light source The light emission by is stopped.

  In the above projection device, the light source emits light constituting the image. The light receiving means receives a part of the light emitted from the light source and outputs an output value corresponding to the light quantity. The setting means has a first reference value corresponding to an allowable upper limit value of the intensity of light emitted from the light source and a second reference value corresponding to an allowable lower limit value of the intensity of light emitted from the light source based on the brightness of the image. Set the value. The control unit stops light emission by the light source when the first reference value set by the setting unit is exceeded or when the second reference value set by the setting unit is not satisfied.

  Thereby, the emission of light is stopped when an abnormality occurs in the light source or the light receiving means. Further, since the first reference value and the second reference value are set to appropriate values based on the brightness of the image, it is possible to detect an abnormality of the apparatus at an early stage without being affected by the brightness of the image. .

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

[First embodiment]
(Device configuration)
FIG. 1 shows a configuration of a projection apparatus 1 according to the first embodiment. As shown in FIG. 1, the projection apparatus 1 includes an image signal input unit 2, a video processing unit 3, a frame memory 4, a ROM 5, a RAM 6, a laser driver 7, a MEMS driver 8, and a MEMS mirror 95. The laser light source unit 9 includes a microlens array 13, a field lens 14, a timing controller 21, an MCU (Micro Controller Unit) 22, and a nonvolatile memory 23. The projection device 1 is used 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 Si input from the outside and outputs it to the video processing unit 3.

  The video processing unit 3 writes the image data input from the image signal input unit 2 into the internal frame memory, and reads the data as needed according to the drive timing of the MEMS mirror 95, and the red (R), green (G), and blue (B ), A control signal corresponding to the brightness of each pixel is sequentially transmitted to the laser driver 7 for each color. Further, the video processing unit 3 integrates the luminance of each pixel of image data in a predetermined section (here, one frame as an example) for each color, and uses the integrated values Vfr, Vfg, and Vfb for each color as a signal Sv. Send to.

  The timing controller 21 controls the read timing of image data from the frame memory of the video processing unit 3. The timing controller 21 also controls the operation timing of the MEMS driver 8 based on the scanning position information Sc output from the MEMS mirror 95.

  The ROM 5 stores a control program and data for operating the video processing unit 3. Various data are sequentially read from and written into the RAM 6 as a work memory when the video processing unit 3 operates.

  The laser driver 7 is a block that generates a signal for driving a laser diode provided in a laser light source unit 9 described later. The laser driver 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 element LD1 based on the control signal output from the video processing unit 3. The blue laser driving circuit 72 drives the blue laser element LD2 based on the control signal output from the video processing unit 3. The green laser driving circuit 73 drives the green laser element LD3 based on a signal output from the video processing unit 3.

  The MEMS driver 8 controls the MEMS mirror 95 based on a signal output from the timing controller 21. The MEMS driver 8 includes a servo circuit and a driver circuit. The servo circuit controls the operation of the MEMS mirror 95 based on the signal from the timing controller 21. The driver circuit amplifies the control signal for the MEMS mirror 95 output from the servo circuit 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 7. Specifically, the laser light source unit 9 includes a red laser element LD1, a blue laser element LD2, a green laser element LD3, collimator lenses 91a to 91c, reflection mirrors 92a to 92c, and a light receiving unit 24. .

  The red laser element LD1 emits red laser light (also referred to as “red laser light Lr”), the blue laser element LD2 emits blue laser light (also referred to as “blue laser light Lb”), and a green laser. The element LD3 emits green laser light (also referred to as “green laser light Lg”). 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 reflects a part of the red laser light Lr and transmits the remaining part. The reflection mirror 92a transmits part of the blue and green laser beams Lb and Lg and reflects the remaining part. 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. Further, part of the red laser light Lr, the blue laser light Lb, and the green laser light Lb is irradiated to the light receiving unit 24.

  A microlens array 13 and a field lens 14 are provided at positions where laser light is emitted from the laser light source unit 9. 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 scans the microlens array 13 under the control of the MEMS driver 8 in order to display an image input to the image signal input unit 2 (hereinafter referred to as “input image”). The scanning position information (for example, information such as the angle of the mirror) at that time is output to the timing controller 21 as the 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 projection 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.

  The light receiving unit 24 includes a photodetector, receives the combined light of the red laser light Lr, the blue laser light Lb, and the green laser light Lb, and outputs a signal Sd indicating a voltage corresponding to the intensity of the combined light to the MCU 22. .

  The nonvolatile memory 23 stores a function indicating an integrated value of luminance in one frame period of image data and an integrated value of one voltage period output from the light receiving unit 24 for each color of R, G, and B. ing. Examples of function data stored in the nonvolatile memory 23 are shown in FIGS.

  FIG. 2A shows a light receiving unit as a design value (ideal value) when the integrated value of one component of the R component luminance of the image data is Vfr and the integrated value of the luminance of the G and B components is zero. 24 is function data indicating an integrated value Oir for one frame period of the voltage value output by 24. Here, “Vfr” includes a plurality of luminance values from zero to the maximum value. That is, FIG. 2A shows standard function data of the integrated value Vfr of the R component luminance and the integrated value Oir of the output voltage.

  Similarly, FIG. 2B shows a design value (ideal value) when the integrated value of the G component luminance of the image data in one frame period is Vfg and the integrated value of the R and B component luminances is zero. As the function data indicating the integrated value Oig for one frame period of the voltage value output by the light receiving unit 24. FIG. 2C shows a light receiving unit as a design value (ideal value) when the integrated value of the B component luminance of the image data in one frame period is Vfb and the integrated value of the R and G component luminances is zero. 24 is function data indicating the integrated value Oib of one voltage period of the voltage value output by 24. As shown in FIGS. 2A to 2C, the slope of the function data differs depending on the color because the voltage value output from the light receiving unit 24 by the color (that is, the wavelength) is the same luminance. This is because they are different.

  As these function data, data actually measured for each product at the time of manufacture may be stored instead of the design value. Thereby, it is possible to suitably cope with variations in individual products.

  The MCU 22 performs laser light emission stop processing based on the voltage value output from the light receiving unit 24 and the integrated values Vfr, Vfg, and Vfb for each color output from the video processing unit 3.

(Light emission stop processing)
Next, the light emission stop process according to the first embodiment will be described. The light emission stop process is a process for stopping the light emission of the laser element when it is recognized that there is an abnormality in the laser elements LD1 to LD3 or the light receiving unit 24 based on the output voltage from the light receiving unit 24.

  FIG. 3 is a flowchart of the light emission stop process according to the first embodiment. This process is mainly performed by the MCU 22 executing a program prepared in advance. Further, this process is repeatedly executed during the operation of the projection apparatus 1.

  First, the MCU 22 calculates a laser light amount value Of based on the output of the light receiving unit 24 (step S1). Specifically, the MCU 22 AD-converts the output voltage of the light receiving unit 24 with a predetermined sampling clock (typically the same as the pixel clock), and acquires it as a digital value. Then, the MCU 22 uses the timing signal received from the timing controller 21 as a trigger, and integrates the digital value of the output voltage from the light receiving unit 24 in one frame period of the image data to obtain the average luminance of the combined light in one frame period. The corresponding laser light amount value Of is calculated.

  Next, the MCU 22 refers to the non-volatile memory 23 and calculates a standard light amount value Ofref (step S2). Specifically, the MCU 22 refers to the standard function data stored in the nonvolatile memory 23, and the integrated value received from the video processing unit 3 for the same frame as the frame for which the laser light amount value Of is calculated in step S1. The integrated values Oir, Oig, Oib in one frame period for each color corresponding to Vfr, Vfg, Vfb are detected. Then, the MCU 22 sets the sum of the detected integrated values Oir, Oig, Oib for each color as the standard light amount value Ofref. The standard light amount value Ofref obtained in this way is a large value when the image indicated by the image signal is bright, and a small value when the image is dark.

  Next, the MCU 22 determines an allowable upper limit value OHlim and an allowable lower limit value OLlim based on the calculated standard light amount value Ofref (step S3). Specifically, the MCU 22 sets a value larger than the standard light amount value Ofref calculated in step S2 by a predetermined ratio as the allowable upper limit value OHlim, and sets a value smaller than the standard light amount value Ofref by a predetermined ratio as the allowable lower limit value OLlim. . The allowable upper limit value OHlim and the allowable lower limit value OLlim thus obtained are large values when the image indicated by the image signal is bright, and are small values when the image is dark.

  The predetermined ratio is appropriately set based on experiments. The predetermined ratio may be 50%, for example. Further, the ratio may be different between the upper limit value and the lower limit value. That is, the allowable upper limit value OHlim may be 50% larger than the standard light amount value Ofref, and the allowable lower limit value OLlim may be 30% smaller than the standard light amount value Ofref.

  Next, the MCU 22 compares the laser light amount value Of calculated in step S1 with the allowable upper limit value OHlim and the allowable lower limit value OLlim determined in step S3 (step S4). When the laser light amount value Of is within the range between the allowable upper limit value OHlim and the allowable lower limit value OLlim (step S4: Yes), the MCU 22 determines that there is no abnormality and ends the process. On the other hand, when the laser light amount value Of is outside the range between the allowable upper limit value OHlim and the allowable lower limit value OLlim (step S4: No), the MCU 22 determines that there is an abnormality and controls the laser driver 8 to switch the laser elements LD1 to LD3. Stop (step S5).

  Specifically, when the laser light amount value Of exceeds the allowable upper limit OHlim, it can be considered that light emission by any of the laser elements LD1 to LD3 is excessive. In this case, by stopping the laser elements LD1 to LD3, an adverse effect on the human body of the user who views the projection image due to excessive light emission is prevented.

  On the other hand, the laser elements LD1 to LD3 are stopped even when the laser light quantity value Of is less than the allowable lower limit value OLlim, for example, for fail-safe against a failure of the photodetector of the light receiving unit 24. If the photodetector fails, the correct amount of light cannot be detected, and there is a possibility of overlooking the excessive light emission of the laser. Furthermore, in the case of a projection apparatus that corrects the drive current of the laser elements LD1 to LD3 so that a target light quantity can be obtained based on the light quantity received by the photodetector, the drive current will not be output if the photodetector fails and no detection voltage is output. May be further increased. Therefore, when the laser light amount value Of is less than the allowable lower limit value OLlim, such a problem is addressed by stopping the light emission of the laser elements LD1 to LD3.

  As described above, in the first embodiment, the reference value for detecting the abnormality of the apparatus is changed according to the brightness of the image to be projected, so that the allowable upper limit value and the allowable lower limit value are fixed. Since it is easy to detect an abnormality regardless of the brightness of the image, the abnormality can be detected more quickly.

[Second Embodiment]
(Device configuration)
In the first embodiment, the light amount of the combined light of the three colors of laser light is detected by one light receiving unit 24, and when there is an abnormality, all of the three laser elements LD1 to LD3 are stopped. Instead, in the second embodiment, a light receiving portion is provided for each color, and abnormality of the laser element is detected individually.

  FIG. 4 shows the configuration of the projection apparatus 1a according to the second embodiment. As can be seen from a comparison with FIG. 1, in the second embodiment, the laser light source unit 9 is provided with light receiving units 24r, 24b, 24g for each color and reflecting mirrors 94r, 94g, 94g. The other configuration is the same as that of the first embodiment.

  The combined light from the reflection mirror 92a in the laser light source unit 9 enters the reflection mirror 94b. The reflection mirror 94b transmits the blue laser light Lr to enter the light receiving unit 24b, and reflects the red laser light Lr and the green laser light Lg. The reflection mirror 94g reflects the green laser light to enter the light receiving unit 24g and transmits the red laser light Lr. The reflection mirror 94r reflects the red laser beam Lr and makes it incident on the light receiving unit 24r. The output voltages of the light receiving units 24r, 24b, and 24g for each color are input to the MCU 22, respectively.

(Light emission stop processing)
FIG. 5 is a flowchart of the light emission stop process according to the second embodiment. This process is also repeatedly performed by the MCU 22 executing a program prepared in advance. In the second embodiment, the same processing is performed for the three colors of R, G, and B laser beams, and FIG. 5 shows only the processing related to the red laser beam representing the three colors. Similar processing is performed for other colors.

  First, the MCU 22 calculates the laser light amount value Of-r of the red laser light from the output of the light receiving unit 24r (step S11). Specifically, the MCU 22 AD-converts the output voltage of the light receiving unit 24r with a predetermined sampling clock, and acquires it as a digital value. Then, the MCU 22 uses the timing signal received from the timing controller 21 as a trigger, and integrates the digital value of the output voltage from the light receiving unit 24r in one frame period of the image data, whereby the average luminance of the red laser light in one frame period A laser light amount value Of-r corresponding to is calculated.

  Next, the MCU 22 refers to the nonvolatile memory 23 and calculates a standard light amount value Ofref-r of the red laser light (step S12). Specifically, the MCU 22 refers to the standard function data stored in the nonvolatile memory 23 and receives from the video processing unit 3 the same frame as the frame for which the laser light amount value Of-r is calculated in step S11. An integrated value Oir for one frame period of red corresponding to the integrated value Vfr is detected. Then, the MCU 22 sets the detected red integrated value Oir as the standard light amount value Ofref-r. The standard light amount value Ofref-r thus obtained is a large value when the red component of the image indicated by the image signal is large, and a small value when the red component is small.

  Next, the MCU 22 determines an allowable upper limit value OHlim-r and an allowable lower limit value OLlim-r based on the calculated standard light amount value Ofref-r (step S13).

  Next, the MCU 22 compares the laser light amount value Of-r calculated in step S11 with the allowable upper limit value OHlim-r and the allowable lower limit value OLlim-r determined in step S13 (step S14). When the laser light amount value Of-r is within the range between the allowable upper limit value OHlim-r and the allowable lower limit value OLlim-r (step S14: Yes), the MCU 22 indicates that there is no abnormality with respect to the red laser element and the red light receiving unit 24r. Determine and end the process. On the other hand, when the laser light quantity value Of-r is outside the range between the allowable upper limit value OHlim-r and the allowable lower limit value OLlim-r (step S14: No), the MCU 22 determines that there is an abnormality and controls the laser driver 8. The red laser element LD is stopped (step S15).

  The above processing is similarly executed for the blue laser light and the green laser light.

  In the second embodiment, an abnormality can be detected for each of R, G, and B colors, so that only the laser element of the color determined to be abnormal can be stopped. Therefore, although the color of the projected image is different from that in the normal state, it is possible to continue projecting the image by emitting only the laser element having a color in which no abnormality is recognized.

DESCRIPTION OF SYMBOLS 1, 1a Projection apparatus 3 Image processing part 7 Laser driver 8 MEMS driver 22 MCU
23 Non-volatile memory 24 Light receiving part 95 MEMS mirror

Claims (12)

A projection device for projecting an image,
A light source that emits light constituting the image;
Control means for controlling the intensity of light emitted by the light source based on an image signal indicating the image;
Setting means for setting a first reference value corresponding to an allowable upper limit value of the intensity of light emitted from the light source based on the brightness of the image indicated by the image signal;
A light receiving means for receiving a part of the light emitted by the light source and outputting an output value corresponding to the received light amount;
With
The control device stops emission of light from the light source when an output value output from the light receiving device exceeds a first reference value set by the setting device. The setting means sets the first reference value based on an integrated value of brightness of a predetermined section in the image signal;
The said control means stops emission of the light by the said light source, when the integrated value of the output value which the said light-receiving means outputs in the said predetermined period exceeds the said 1st reference value. Projection device. The light source includes a plurality of light emitting elements that emit each of the three primary colors,
The setting means corresponds to a first allowable upper limit value of the intensity of combined light of the light emitted by the plurality of light emitting elements, based on the brightness of each of the three primary colors of the image indicated by the image signal. Set the reference value,
The projection apparatus according to claim 1, wherein the light receiving unit receives a part of the combined light emitted from the light source. A projection device for projecting an image,
A light source that emits light constituting the image;
Control means for controlling the intensity of light emitted by the light source based on an image signal indicating the image;
Setting means for setting a second reference value corresponding to an allowable lower limit value of the intensity of light emitted from the light source based on the brightness of the image indicated by the image signal;
A light receiving means for receiving a part of the light emitted by the light source and outputting an output value corresponding to the received light amount;
With
The control unit stops the emission of light by the light source when an output value output from the light receiving unit is less than a second reference value set by the setting unit. The setting means sets the second reference value based on an integrated value of brightness of a predetermined section in the image signal,
The said control means stops emission of the light by the said light source, when the integrated value of the output value which the said light-receiving means outputs in the said predetermined period does not satisfy the said 2nd reference value. The projection device described. The light source includes a plurality of light emitting elements that emit each of the three primary colors,
The setting means has a second lower limit corresponding to the allowable lower limit of the intensity of the combined light of the light emitted from the plurality of light emitting elements, based on the brightness of each of the three primary colors of the image indicated by the image signal. Set the reference value,
The projection device according to claim 4, wherein the light receiving unit receives a part of the combined light emitted from the light source. A projection method executed by a projection apparatus comprising: a light source that emits light constituting an image; and a light receiving unit that receives a part of the light emitted from the light source and outputs an output value corresponding to the received light amount Because
A control step of controlling the intensity of light emitted from the light source based on an image signal indicating the image, and an allowable upper limit value of the intensity of light emitted from the light source based on the brightness of the image indicated by the image signal. A setting step for setting a corresponding first reference value;
Have
The control method includes a step of stopping light emission by the light source when an output value output from the light receiving unit exceeds a first reference value set by the setting step. A projection method executed by a projection apparatus comprising: a light source that emits light constituting an image; and a light receiving unit that receives a part of the light emitted from the light source and outputs an output value corresponding to the received light amount Because
A control step of controlling the intensity of light emitted from the light source based on an image signal indicating the image; and an allowable lower limit value of the intensity of light emitted from the light source based on the brightness of the image indicated by the image signal. A setting step for setting a corresponding second reference value;
Have
The projecting method characterized in that the control step stops light emission by the light source when an output value output from the light receiving means is less than a second reference value set in the setting step. A light source that emits light constituting an image, a light receiving unit that receives a part of the light emitted from the light source, and outputs an output value corresponding to the received light amount, and a computer, and is executed by a projection device A program
A control step of controlling the intensity of light emitted from the light source based on an image signal indicating the image; corresponding to an allowable upper limit value of the intensity of light emitted from the light source based on the brightness of the image indicated by the image signal A setting step for setting the first reference value
To the computer,
The control step stops the emission of light by the light source when an output value output from the light receiving unit exceeds a first reference value set in the setting step. A light source that emits light constituting an image, a light receiving unit that receives a part of the light emitted from the light source, and outputs an output value corresponding to the received light amount, and a computer, and is executed by a projection device A program
A control step of controlling the intensity of light emitted from the light source based on an image signal indicating the image; corresponding to an allowable lower limit of the intensity of light emitted from the light source based on the brightness of the image indicated by the image signal A setting step for setting a second reference value
To the computer,
The control step stops the emission of light by the light source when the output value output from the light receiving means is less than the second reference value set in the setting step.   A storage medium storing the program according to claim 9 or 10. A projection device for projecting an image,
A light source that emits light constituting the image;
Control means for controlling the intensity of light emitted by the light source based on an image signal indicating the image;
Based on the brightness of the image indicated by the image signal, the first reference value corresponding to the allowable upper limit value of the intensity of light emitted from the light source, and the allowable lower limit value of the intensity of light emitted from the light source. Setting means for setting a second reference value;
A light receiving means for receiving a part of the light emitted by the light source and outputting an output value corresponding to the received light amount;
With
The control means, when the output value output by the light receiving means exceeds the first reference value set by the setting means, or when the output value is less than the second reference value set by the setting means, A projection apparatus that stops light emission by the light source.

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