JP2015040955A - Projection device, control method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection device capable of appropriately reducing obstruction to broadcast or communication by a pixel clock.SOLUTION: The projection device for protecting an image onto a projection surface comprises: emission means for emitting a light beam modulated on the basis of a video signal; a mirror element for reflecting the light beam and scanning on the projection surface; generation means for generating, as a pixel clock for the video signal which is the basis of modulation of the light beam emitted by the emission means, a pixel clock of a frequency derived by multiplying the resonance frequency possessed by the mirror element by a first multiplication number; and acquisition means for acquiring reception state information indicating the reception state of reception means for receiving broadcast or communication. The generation means switches the first multiplication number to a second multiplication number in accordance with the reception state information as it generates the pixel clock.

Description

  The present invention relates to a technical field of a projection apparatus that projects an image.

  2. Description of the Related Art Conventionally, projection apparatuses that perform raster scanning using a resonant optical scanner such as a MEMS (Micro Electro Mechanical Systems) mirror are known. In such a projection apparatus, a technique for performing control for making the resonance frequency of the resonance type optical scanner coincide with the horizontal scanning frequency in order to obtain a large display width of horizontal scanning is known. However, due to individual variations of the resonant optical scanner, temperature changes, and changes over time, the resonant frequency of the resonant optical scanner may not be constant, and it may be difficult to match the resonant frequency with the horizontal scanning frequency.

  For example, Patent Literature 1 proposes a technique for solving such a problem. In Patent Document 1, an image signal is temporarily stored in a buffer memory, and based on a readout clock (pixel clock) generated by using a PLL circuit from a horizontal scanning drive signal that performs resonance vibration, the above-described method is used. A technique for reading out an image signal of each horizontal line from a buffer memory has been proposed.

JP-A-11-146222

  By the way, when the projection apparatus as described above is applied to an in-vehicle head-up display or the like, since the installation position of the projection apparatus is in the vicinity of the windshield, an antenna used for terrestrial digital broadcasting, GPS (Global Positioning System), etc. There is a tendency for the distance to the projection apparatus to be closer. For this reason, a pixel clock generated in the projection apparatus and its harmonics may interfere with reception of communication using such radio waves. This is because the pixel clock frequency is generally high. Here, in the technique described in Patent Document 1 described above, since the frequency of the pixel clock changes due to individual variations of mirror elements, temperature changes, changes with time, etc., the pixel clocks interfere with a wide frequency band. There was a possibility.

  Examples of the problem to be solved by the present invention are as described above. It is an object of the present invention to provide a projection apparatus and the like that can appropriately reduce interference with broadcasting or communication due to a pixel clock.

  In the invention described in the claims, the projection device that projects an image on the projection plane emits a light beam modulated based on an image signal, and scans the projection plane by reflecting the light beam. Generation means for generating a pixel clock having a frequency obtained by multiplying a resonance frequency of the mirror element by a first multiplication number as a pixel clock of an image signal which is a basis of modulation of the light beam emitted by the emission element. And acquisition means for acquiring reception status information indicating the reception status of the reception means for receiving broadcast or communication, and the generation means sets the first multiplication number to a second value according to the reception status information. The pixel clock is generated by switching to a multiplication number of.

  In the invention described in claim, there is provided an emission unit that emits a light beam modulated based on an image signal, and a mirror element that reflects the light beam and scans it on the projection surface. The control method executed by the projection apparatus for projecting an image onto the mirror is configured such that the resonance frequency of the mirror element is a first multiplication number as a pixel clock of an image signal that is a basis of modulation of the light beam emitted by the emission unit. A generation step of generating a pixel clock having a multiplied frequency, and an acquisition step of acquiring reception status information indicating a reception status of a receiving means for receiving broadcast or communication, wherein the generation step is in accordance with the reception status information. The pixel clock is generated by switching the first multiplication number to the second multiplication number.

  In the invention described in claim, there is provided an emission unit that emits a light beam modulated based on an image signal, a mirror element that reflects the light beam and scans it on a projection surface, and a computer, A program executed by a projection device that projects an image on a projection surface is configured to first multiply a resonance frequency of the mirror element as a pixel clock of an image signal that is a basis of modulation of a light beam emitted by the emission unit. Causing the computer to function as a generation unit that generates a pixel clock having a frequency multiplied by a number, an acquisition unit that acquires reception status information indicating a reception status of a reception unit that receives broadcast or communication, and the generation unit According to the situation information, the pixel clock is generated by switching the first multiplication number to the second multiplication number.

The structure of the projection apparatus which concerns on a present Example is shown. The processing flow concerning a present Example is shown.

  In one aspect of the present invention, a projection apparatus that projects an image on a projection plane emits a light beam modulated based on an image signal, and scans the projection plane by reflecting the light beam. Generation means for generating a pixel clock having a frequency obtained by multiplying a resonance frequency of the mirror element by a first multiplication number as a pixel clock of an image signal which is a basis of modulation of the light beam emitted by the emission element. And acquisition means for acquiring reception status information indicating the reception status of the reception means for receiving broadcast or communication, and the generation means sets the first multiplication number to a second value according to the reception status information. The pixel clock is generated by switching to a multiple of.

  In the above projection apparatus, the generating means uses a pixel clock having a frequency obtained by multiplying the resonance frequency of the mirror element by the first multiplication number as the pixel clock of the image signal that is the basis of modulation of the light beam emitted by the emitting means. The generating and acquiring unit acquires reception status information indicating a reception status of a receiving unit that receives broadcast or communication (for example, television or radio broadcast or GPS communication). The generating means generates a pixel clock by switching the first multiplication number to the second multiplication number in accordance with such reception status information. Thus, by applying the pixel clock generated based on the multiplication number switched according to the reception status information, it is possible to appropriately reduce the interference by the pixel clock with respect to the broadcast or communication being received by the receiving means.

  In one aspect of the above projection apparatus, the acquisition unit acquires the reception status information including reception channel information indicating a reception channel of the reception unit, and the generation unit changes each time the reception channel information changes. A pixel clock is generated by switching the first multiplication number to the second multiplication number. Thereby, it is possible to switch to an appropriate multiplication number every time the reception channel of the reception means is switched.

  In another aspect of the projection apparatus, the acquisition unit acquires the reception status information including reception quality information indicating reception quality of the reception unit, and the generation unit sets the resonance frequency to the second frequency. The reception quality indicated by the reception quality information when the pixel clock multiplied by the multiplication number is generated is the reception quality indicated by the reception quality information when the pixel clock obtained by multiplying the resonance frequency by the first multiplication number is generated. If it is better, the pixel clock is generated with the second multiplication number fixed. Thereby, it is possible to apply a pixel clock generated based on the multiplication number that optimizes the reception quality of the receiving means.

  In another aspect of the projection apparatus, the acquisition unit acquires the reception status information including reception channel information indicating a reception channel of the reception unit, and the generation unit sets the resonance frequency to the first frequency. When the harmonic component of the pixel clock multiplied by the multiplication number is included in the frequency band corresponding to the reception channel indicated by the reception channel information, the pixel clock is switched from the first multiplication number to the second multiplication number. Is generated. Thereby, a pixel clock generated based on an appropriate multiplication number corresponding to the reception channel of the reception unit can be applied.

  In another aspect of the above projection apparatus, the projector further includes a resolution conversion unit that converts a resolution of an image signal that is a basis for modulation of the light beam emitted by the emission unit, and the generation unit includes the resolution conversion unit. The resolution of the image signal is converted so that the size of the image projected on the projection plane does not change according to the multiplication number by which the resonance frequency is multiplied. Thereby, the change in the size of the projection image due to the change in the pixel clock can be appropriately suppressed.

  In another aspect of the present invention, the image forming apparatus includes: an emission unit that emits a light beam modulated based on an image signal; and a mirror element that reflects the light beam and scans the projection surface. The control method executed by the projection device for projecting the image is obtained by multiplying the resonance frequency of the mirror element by a first multiplication number as the pixel clock of the image signal that is the basis of modulation of the light beam emitted by the emission means. A generation step of generating a pixel clock of a frequency, and an acquisition step of acquiring reception status information indicating a reception status of a receiving means for receiving broadcast or communication, wherein the generation step is based on the reception status information, A pixel clock is generated by switching the first multiplication number to the second multiplication number.

  In still another aspect of the present invention, the projection apparatus includes: an emission unit that emits a light beam modulated based on an image signal; a mirror element that reflects the light beam and scans it on a projection surface; and a computer. A program executed by a projection device that projects an image on a surface has a resonance frequency of the mirror element as a pixel clock of an image signal that is a basis of modulation of a light beam emitted by the emission unit, and a first multiplication number. Causing the computer to function as a generating unit that generates a pixel clock having a frequency multiplied by 1 and an acquisition unit that acquires reception status information indicating a reception status of a receiving unit that receives broadcast or communication. The pixel clock is generated by switching the first multiplication number to the second multiplication number according to the information.

  Note that the above program may be handled in a state of being recorded on a recording medium.

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

[Device configuration]
FIG. 1 shows a configuration of a projection apparatus 1 according to the present embodiment. For example, the projection apparatus 1 is used by being mounted on a vehicle. In one example, the projection device 1 is applied to a head-up display that visually recognizes an image as a virtual image from the position (eye point) of the user's eyes.

  As shown in FIG. 1, the projection apparatus 1 mainly includes an image signal input unit 2, a video processing unit 31, a timing controller 32, a frame memory 4, a ROM 5, a RAM 6, a laser driver 7, and a MEMS. A driver 8, a laser light source unit 9, an MCU (Micro Control Unit) 10, and a screen 11 are provided. Below, the outline | summary of each component which the projector 1 has is demonstrated.

  The image signal input unit 2 acquires an image signal Si input from the outside, and outputs the image signal Si to the video processing unit 31.

  The video processing unit 31 is a block that controls the laser driver 7 based on the image signal Si or the like input from the image signal input unit 2, and is configured as, for example, an ASIC (Application Specific Integrated Circuit). Specifically, the video processing unit 31 writes digital data corresponding to the image signal Si to the frame memory 4, and stores the digital data in the frame memory 4 based on the pixel clock signal Sp corresponding to the pixel clock generated by the timing controller 32. The written digital data is read and converted into bit data. Then, the video processing unit 31 converts the converted bit data into a signal representing a light emission pattern of each laser and outputs the signal to the laser driver 7.

  The timing controller 32 is a block that controls the MEMS driver 8, and is configured as an ASIC, for example. Specifically, the timing controller 32 operates the timing of the MEMS mirror 12 via the MEMS driver 8 based on the scanning position information signal Sc indicating the scanning position information input from the MEMS mirror 12 in the laser light source unit 9. To control. In this case, the timing controller 32 controls the drive frequency of the MEMS mirror 12. In addition, the timing controller 32 uses an instruction signal Sin for switching the frequency of the pixel clock from the MCU 10 (corresponding to a signal for instructing switching of the multiplication number) or the like, so that an internal multiplier (not shown) has a pixel. A clock is generated, and a pixel clock signal Sp corresponding to the generated pixel clock is output to the video processing unit 31. In this case, the multiplier in the timing controller 32 generates a pixel clock by multiplying the drive frequency of the MEMS mirror 12 by a multiplication number corresponding to the instruction signal Sin.

  Image data separated by the video processing unit 31 is written into the frame memory 4. The ROM 5 stores a control program and data for operating the video processing unit 31 and the like, and various data are sequentially read and written in the RAM 6 as a work memory when the video processing unit 31 and the like operate.

  The MCU 10 controls the video processing unit 31 and the timing controller 32. Specifically, the MCU 10 acquires the reception quality information signal Sr corresponding to the reception quality information indicating the reception quality of the receiver 101 from the receiver 101 provided outside the projection apparatus 1, and receives the reception quality information signal Sr. Accordingly, the instruction signal Sin for switching the frequency of the pixel clock, that is, the instruction signal Sin for switching the multiplication number used by the multiplier in the timing controller 32 is output to the timing controller 32. Here, the receiver 101 corresponds to a television, radio tuner, GPS receiver, or the like. The reception quality information is information including at least one of S / N, C / N, audio level, bit error rate, and the like of the signal demodulated by the receiver 101. Note that the receiver 101 is not limited to be provided outside the projection apparatus 1, and the receiver 101 may be provided inside the projection apparatus 1.

  The laser driver 7 is a block that generates a signal for driving a laser diode (LD) provided in the laser light source unit 9, and is configured as, for example, an IC (Integrated Circuit). The laser driver 7 includes a red laser driving circuit 71, a green laser driving circuit 72, and a blue laser driving circuit 73. The red laser driving circuit 71, the green laser driving circuit 72, and the blue laser driving circuit 73 are respectively based on a signal (specifically, a signal representing a light emission pattern) output from the video processing unit 31 and a red laser LD1, a green laser. The LD2 and the blue laser LD3 are driven.

  The MEMS driver 8 controls the MEMS mirror 12 based on a signal output from the timing controller 32.

  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 mainly includes a red laser LD1, a green laser LD2, a blue laser LD3, collimator lenses 91a to 91c, dichroic mirrors 92a to 92c, and a MEMS mirror 12. .

  The red laser LD1 emits red laser light, the green laser LD2 emits green laser light, and the blue laser LD3 emits blue laser light. Hereinafter, when the red laser LD1, the green laser LD2, and the blue laser LD3 are used without being distinguished from each other, they are simply referred to as “laser LD”, and the red laser light, the green laser light, and the blue laser light are used without being distinguished from each other. In this case, it is simply expressed as “laser light”. Further, in this specification, laser light may be referred to as “beam” or “light beam”.

  The collimator lenses 91a, 91b, and 91c convert the red laser light, the green laser light, and the blue laser light into parallel lights and emit them to the dichroic mirrors 92a to 92c, respectively. The dichroic mirror 92b reflects green laser light, and the dichroic mirror 92a transmits green laser light and reflects red laser light. The dichroic mirror 92c transmits only blue laser light and reflects green laser light and red laser light. The blue laser light transmitted through the dichroic mirror 92 c and the green laser light and red laser light reflected by the dichroic mirror 92 c are incident on the MEMS mirror 12.

  The MEMS mirror 12 reflects the laser beam incident through the dichroic mirror 92c as described above toward the screen 11. Specifically, the MEMS mirror 12 operates to scan the screen 11 with laser light so as to display an image corresponding to the image input to the image signal input unit 2 under the control of the MEMS driver 8. Further, the MEMS mirror 12 detects scanning position information (for example, information indicating the rotation angle of the MEMS mirror 12) by a built-in piezo element (not shown), and timings a scanning position information signal Sc corresponding to the scanning position information. Output to the controller 32.

  The screen 11 receives the beam reflected by the MEMS mirror 12. Therefore, scanning with the laser beam is performed on the screen 11 by the operation of the MEMS mirror 12 as described above. For example, the screen 11 functions to form an intermediate image of an image to be displayed. In one example, a diffusion plate such as EPE (Exit-Pupil Expander) can be applied as the screen 11.

  The red laser LD1, the green laser LD2, and the blue laser LD3 correspond to an example of “emission means” in the present invention. The MEMS mirror 12 corresponds to an example of a “mirror element” in the present invention. The timing controller 32 (which may include the MCU 10) corresponds to an example of “generating means” in the present invention. The MCU 10 corresponds to an example of “acquiring means” in the present invention. The video processing unit 31 corresponds to an example of “resolution conversion means” in the present invention. The screen 11 corresponds to an example of a “projection plane” in the present invention, and the receiver 101 corresponds to an example of a “reception unit” in the present invention.

[Control method]
Next, a control method executed by the projection apparatus 1 in the present embodiment will be described. In this embodiment, the projection apparatus 1 performs control to change the pixel clock in accordance with reception quality information indicating the reception quality of the receiver 101 in order to reduce interference with broadcast or communication being received by the receiver 101. . In this case, each component in the projection apparatus 1 performs control as presented below.

  First, the timing controller 32 controls the MEMS driver 8 so that the MEMS mirror 12 is driven at a standard horizontal scanning frequency (corresponding to a standard resonance frequency of the MEMS mirror 12 to be used). The timing controller 32 then passes through the MEMS driver 8 based on the scanning position information signal Sc acquired from the piezoelectric element in the MEMS mirror 12 when the drive frequency of the MEMS mirror 12 is changed from the standard horizontal scanning frequency. Feedback control of the MEMS mirror 12 is performed. By doing so, the timing controller 32 detects the drive frequency at which the amplitude of the MEMS mirror 12 is maximized. The timing controller 32 uses the detected drive frequency as the resonance frequency of the MEMS mirror 12 (specifically, the resonance frequency relating to the scanning in the horizontal direction; the same shall apply hereinafter).

  Next, the MCU 10 sets the multiplication number used when the multiplier in the timing controller 32 generates the pixel clock to the first multiplication number (hereinafter, referred to as “first multiplication number a” as appropriate). An instruction signal Sin is output to the timing controller 32. The multiplier in the timing controller 32 generates a pixel clock by multiplying the resonance frequency of the MEMS mirror 12 detected as described above by the first multiplication number a in accordance with the instruction signal Sin. Then, the MCU 10 acquires the reception quality information signal Sr output from the receiver 101 when the pixel clock generated as described above is applied.

  Next, the MCU 10 sets the multiplication number used when the multiplier in the timing controller 32 generates the pixel clock to the second multiplication number (hereinafter, referred to as “second multiplication number b” as appropriate). Is output to the timing controller 32. That is, the instruction signal Sin for switching the multiplication number used by the multiplier from the first multiplication number a to the second multiplication number b is output. The multiplier in the timing controller 32 generates the pixel clock by multiplying the resonance frequency of the MEMS mirror 12 detected as described above by the second multiplication number b in accordance with the instruction signal Sin. Then, the MCU 10 acquires the reception quality information signal Sr output from the receiver 101 when the pixel clock generated as described above is applied.

  Next, the MCU 10 is based on the reception quality information signal Sr acquired when the first multiplication number a is used and the reception quality information signal Sr acquired when the second multiplication number b is used. Then, it is determined whether the reception quality of the receiver 101 when the second multiplication number b is used is better than the reception quality of the receiver 101 when the first multiplication number a is used. When the reception quality when the second multiplication number b is used is better than the reception quality when the first multiplication number a is used, the MCU 10 uses the multiplication used by the multiplier in the timing controller 32. The number is fixed to the second multiplication number b. On the other hand, when the reception quality when the second multiplication number b is used is not better than the reception quality when the first multiplication number a is used, the MCU 10 The multiplication number used by the multiplier is fixed to the first multiplication number a. The MCU 10 causes the timing controller 32 to send an instruction signal Sin for causing the multiplier to set the multiplier (the first multiplier a or the second multiplier b) thus determined in the timing controller 32. Output.

  According to the control method described above, it is possible to appropriately reduce interference caused by the pixel clock with respect to broadcast or communication being received by the receiver 101.

  Note that, when performing control to change the pixel clock as described above, the video processing unit 31 converts the resolution of the image so that the size of the image (projected image) projected by the projection device 1 does not change. It is preferable to carry out the treatment. Specifically, when the multiplication factor for generating the pixel clock is changed under the control of the MPU 10, the video processing unit 31 restores the image data stored in the frame memory 4 so that the projected image does not expand or contract. It is preferable to sample, convert it to a signal representing the emission pattern of each RGB laser beam, and supply it to the laser driver 7. The reason for this is as follows. Since the horizontal scanning speed of the MEMS mirror 12 is a speed corresponding to the resonance frequency, it does not depend on the frequency of the pixel clock. Therefore, if the initial value of the frequency of the pixel clock generated using a certain multiplication number is “fp0” and the frequency of the pixel clock generated using the multiplication number changed from the multiplication number is “fp1”, For example, when “fp1” is higher than “fp0”, when the image data stored in the frame memory 4 is read as it is, the image per horizontal line is displayed in a contracted manner. On the other hand, when “fp1” is lower than “fp0”, if the image data stored in the frame memory 4 is read as it is, the image per horizontal line will be stretched and displayed.

  Therefore, the video processing unit 31 stores the image in the frame memory 4 at a timing based on the pixel clock signal Sp input from the timing controller 32 in order to suppress a change in the size of the projection image caused by the change in the pixel clock. Resampling the image data to convert the resolution. Specifically, the video processing unit 31 changes the frequency of the pixel clock from “fp0” to “fp1” if the horizontal resolution is composed of M pixels when the frequency of the pixel clock is “fp0”. In this case, a process of changing the horizontal resolution from M pixels to N pixels (N = M × fp1 / fp0) is performed. For performing such resolution conversion, various known techniques can be applied. In one example, when the number of pixels of the image to be displayed is larger than the number of pixels of the original image data (image data input from the image signal input unit 2), the video processing unit 31 displays an image of the insufficient pixels. Data is generated using the original image data (for example, processing is performed using image data of pixels around the deficient pixels), and the pixel of the image to be displayed is more than the pixel of the original image data When the number is reduced, a process of reading out the image data obtained by thinning out the original image data is performed.

  In addition, the video processing unit 31 performs the resolution conversion as described above, and at the same time, emits laser light of each color of RGB so that the projection position of the image does not shift according to the change in the multiplication factor for generating the pixel clock. It is preferable to perform processing for changing the output timing of a signal representing a pattern.

[Processing flow]
Next, a processing flow according to the present embodiment will be described with reference to FIG. FIG. 2 shows a flowchart for determining the multiplication number to be adopted. In this flow, by examining the reception quality of the receiver 101 when each of the two multiplication numbers (the first multiplication number a and the second multiplication number b) is used, that is, generated from each of the two multiplication numbers. The multiplication factor to be adopted is determined by examining the influence of the interference on broadcasting or communication caused by the pixel clock. Specifically, the multiplication number with the better reception quality of the receiver 101 out of the two multiplication numbers is determined as the multiplication number to be adopted. That is, of the two multiplication numbers, the multiplication number that is less affected by the interference with broadcasting or communication due to the pixel clock is determined as the multiplication number to be adopted.

  First, in step S <b> 11, the timing controller 32 detects the resonance frequency of the MEMS mirror 12 (hereinafter referred to as “resonance frequency fc” as appropriate). Specifically, the timing controller 32 is based on the scanning position information signal Sc acquired from the piezo element in the MEMS mirror 12 when the drive frequency of the MEMS mirror 12 is changed from the standard horizontal scanning frequency. The resonance frequency fc is detected. In this case, the timing controller 32 detects the drive frequency at which the amplitude of the MEMS mirror 12 is maximum as the resonance frequency fc. Then, the process proceeds to step S12.

  In step S12, the MCU 10 acquires the current reception channel of the receiver 101 and stores it in the RAM 6 or the like. Then, the process proceeds to step S13.

  In step S13, the MCU 10 outputs an instruction signal Sin for setting the multiplication number used by the multiplier in the timing controller 32 to the first multiplication number a to the timing controller 32, and the multiplier in the timing controller 32 In accordance with the instruction signal Sin, the resonance frequency fc detected in step S11 is multiplied by the first multiplication number a to generate a pixel clock. In this case, the multiplier generates a pixel clock having a frequency obtained from “fc × a” (hereinafter referred to as “first frequency fp0” as appropriate). The projection apparatus 1 projects an image using the pixel clock having the first frequency fp0 generated in this way. Then, the process proceeds to step S14.

  In step S14, the MCU 10 acquires the reception quality information signal Sr output from the receiver 101 when using the pixel clock generated in step S13. Then, the MCU 10 stores the reception quality information corresponding to the reception quality information signal Sr in the RAM 6 or the like. Thereafter, the process proceeds to step S15.

  In step S15, the MCU 10 obtains the instruction signal Sin for setting the multiplication number used by the multiplier in the timing controller 32 to the second multiplication number b, that is, the multiplication number used by the multiplier from the first multiplication number a. The instruction signal Sin for switching to the second multiplication number b is output to the timing controller 32, and the multiplier in the timing controller 32 sets the resonance frequency fc detected in step S11 to the second frequency according to the instruction signal Sin. The pixel clock is generated by multiplying by the multiplication number b. In this case, the multiplier generates a pixel clock having a frequency obtained from “fc × b” (hereinafter referred to as “second frequency fp1” as appropriate). The projection apparatus 1 projects an image using the pixel clock having the second frequency fp1 generated in this way. Then, the process proceeds to step S16.

  In step S16, the MCU 10 acquires the reception quality information signal Sr output from the receiver 101 when using the pixel clock generated in step S15. Then, the MCU 10 stores the reception quality information corresponding to the reception quality information signal Sr in the RAM 6 or the like. Thereafter, the process proceeds to step S17.

  In step S17, the MCU 10 acquires the current reception channel of the receiver 101, and the reception channel has not changed from the reception channel acquired in step S12 (that is, the reception channel stored in the RAM 6 or the like in step S12). It is determined whether or not. That is, the MCU 10 determines whether or not the reception channel has changed during the processing of steps S13 to S16. In this determination, since the influence of the interference on the broadcast or communication caused by the pixel clock tends to change depending on the reception channel, in order to eliminate the influence due to the change of the reception channel, it is fixed to one reception channel. Is performed to determine an appropriate multiplication number corresponding to the reception channel.

  If the reception channel has not changed (step S17: Yes), the process proceeds to step S18. On the other hand, when the reception channel changes (step S17: No), the process returns to step S12. In this case, the process after step S12 is performed again.

  In step S18, the reception quality of the receiver 101 when the MCU 10 uses the second multiplication number b based on the reception quality information stored in the RAM 6 or the like in steps S14 and S16 is the first multiplication number a. It is determined whether or not the reception quality of the receiver 101 is improved.

  If the reception quality when the second multiplication number b is used is better than the reception quality when the first multiplication number a is used (step S18: Yes), the process proceeds to step S19. In step S19, the MCU 10 determines the multiplication number used by the multiplier in the timing controller 32 as the second multiplication number b. Then, the MCU 10 outputs to the timing controller 32 an instruction signal Sin for causing the multiplier in the timing controller 32 to set the second multiplication number b thus determined. Then, the process ends.

  On the other hand, when the reception quality when the second multiplication number b is used is not better than the reception quality when the first multiplication number a is used (step S18: No), the process is step S20. Proceed to In step S20, the MCU 10 determines the multiplication number used by the multiplier in the timing controller 32 as the first multiplication number a. Then, the MCU 10 outputs to the timing controller 32 an instruction signal Sin for causing the multiplier in the timing controller 32 to set the first multiplication number a thus determined. Then, the process ends.

  According to the processing flow described above, pixels for broadcast or communication being received by the receiver 101 while appropriately ensuring a wide horizontal scanning display width regardless of variations or changes in the resonance frequency of the MEMS mirror 12. It is possible to appropriately reduce the interference caused by the clock.

  Note that when the MCU 10 determines the multiplication number used by the multiplier in the timing controller 32 in step S19 or S20, the MCU 10 also determines the determined multiplication number (the first multiplication number a and the second multiplication number). b) is output. This is because the video processing unit 31 performs processing such as resolution conversion as described above.

  Further, when the reception channel of the receiver 101 changes after the processing flow of FIG. 2 ends, the processing flow may be executed again. In short, every time the reception channel changes, the multiplication number to be adopted may be determined based on the reception quality of the receiver 101. This is because the multiplication factor to be adopted tends to change as the influence of the interference on the broadcast or communication caused by the pixel clock changes according to the reception channel.

[Modification]
Below, the modification suitable for an above-described Example is shown. It should be noted that the following modifications can be applied to the above-described embodiments in any combination.

(Modification 1)
In the above-described embodiment, the pixel clock is generated by switching the two multiplication numbers (the first multiplication number a and the second multiplication number b), but the pixel clock is generated by switching three or more multiplication numbers. You may do it. In that case, by checking the reception quality of the receiver 101 when each of the three or more multiplication numbers is used, that is, broadcasting or communication caused by the pixel clock generated from each of the three or more multiplication numbers It is only necessary to determine the multiplication factor to be adopted by examining the influence of interference on the system. Specifically, among the multiples of three or more, the multiplication number with the best reception quality of the receiver 101, that is, the influence of interference on broadcasting or communication due to the pixel clock among the multiples of three or more. The number of multiplications with the least number may be determined as the number of multiplications to be adopted.

(Modification 2)
In the above-described embodiment, the multiplication number to be adopted is determined based on the reception quality of the receiver 101. However, the multiplication number to be adopted may be determined based on the reception channel of the receiver 101. In other words, in the above-described embodiment, the multiplication number of the pixel clock that is less disturbed for a certain reception channel is determined based on the reception quality of the receiver 101. Accordingly, the applied multiplication number may be changed. In that case, instead of acquiring the reception quality information indicating the reception quality from the receiver 101, the MCU 10 may acquire the reception channel information indicating the reception channel from the receiver 101. The reception quality information and the reception channel information are included in “reception status information” indicating the reception status of the receiving means (receiver 101) in the present invention.

  Specifically, the MCU 10 performs the following processing. First, the frequency band corresponding to each reception channel is stored in advance in the ROM 5 or the like, and the MCU 10 acquires the frequency band corresponding to the reception channel indicated by the reception channel information acquired from the receiver 101 from the ROM 5 or the like. The resonance frequency fc of the MEMS mirror 12 detected by the timing controller 32 is acquired from the timing controller 32. Then, the MCU 10 obtains a harmonic component of the pixel clock from the acquired resonance frequency fc, and determines the multiplication number of the pixel clock based on the harmonic component and the frequency band corresponding to the acquired reception channel. Specifically, the MCU 10 determines the multiplication number of the pixel clock so that the harmonic components of the pixel clock do not overlap within the frequency band corresponding to the reception channel.

  For example, in a configuration in which two multiplication numbers (first multiplication number a and second multiplication number b) are switched and used, the MCU 10 determines the first frequency from the resonance frequency fc, the first multiplication number a, and the natural number n. The frequency of the harmonic component of the pixel clock when the multiplication number a is used is obtained from “fc × a × n”. Then, the MCU 10 determines whether or not the frequency of the obtained harmonic component is included in the frequency band corresponding to the reception channel. When the frequency of the determined harmonic component is included in the frequency band corresponding to the reception channel, the MCU 10 determines the multiplication number used by the multiplier in the timing controller 32 as the second multiplication number b.

  In addition, in the configuration in which three or more multiplications are switched and used, the frequency of the harmonic component of the pixel clock is obtained for each of the three or more multiplications, and each of the obtained harmonic component frequencies and the reception channel are supported. By comparing the frequency band to be used, it is only necessary to determine a multiplication number such that the frequency of the harmonic component is not included in the frequency band corresponding to the reception channel among the three or more multiplication numbers. In this case, when there are two or more multiplications that do not include the frequency of the harmonic component in the frequency band corresponding to the reception channel, the reception quality of the receiver 101 among the two or more multiplications. Should determine the best multiplication factor.

(Modification 3)
In the above-described embodiment, it has been described that the multiplication number to be adopted should be determined based on the reception quality of the receiver 101 every time the reception channel changes, but the reception quality of the receiver 101 is not considered. In addition, every time the reception channel changes, the multiplication number to be adopted may be switched. For example, every time the reception channel changes, the applied multiplication number may be switched between the first multiplication number a and the second multiplication number b.

(Modification 4)
In the above-described embodiment, the image signal Si is input to the video processing unit 31 from the outside via the image signal input unit 2, but a GDC (Graphics Display Controller) or the like instead of the image signal input unit 2 is a projection device. 1 may be provided so that an image signal corresponding to an image drawn by the GDC is input to the video processing unit 31.

(Modification 5)
In the above-described embodiment, an example in which the projection apparatus 1 is applied to an in-vehicle head-up display has been shown, but the present invention is not limited to application to a head-up display. The present invention can be applied to various display devices.

DESCRIPTION OF SYMBOLS 1 Projection apparatus 2 Image signal input part 4 Frame memory 7 Laser driver 8 MEMS driver 9 Laser light source part 10 MCU
12 MEMS mirror 31 Video processing unit 32 Timing controller 101 Receiver

Claims (7)

A projection device that projects an image on a projection surface,
An emission means for emitting a light beam modulated based on an image signal;
A mirror element that reflects the light beam and scans the projection surface;
Generating means for generating a pixel clock having a frequency obtained by multiplying a resonance frequency of the mirror element by a first multiplication number as a pixel clock of an image signal that is a basis of modulation of the light beam emitted by the emitting means;
An acquisition means for acquiring reception status information indicating a reception status of a reception means for receiving broadcast or communication;
With
The generation unit generates a pixel clock by switching the first multiplication number to a second multiplication number in accordance with the reception status information. The acquisition means acquires the reception status information including reception channel information indicating a reception channel of the reception means,
2. The projection apparatus according to claim 1, wherein the generation unit generates the pixel clock by switching the first multiplication number to the second multiplication number each time the reception channel information changes. The acquisition means acquires the reception status information including reception quality information indicating reception quality of the reception means,
The generation means is a pixel clock in which the reception quality indicated by the reception quality information when generating the pixel clock obtained by multiplying the resonance frequency by the second multiplication number is the resonance frequency multiplied by the first multiplication number. 3. The projection according to claim 1, wherein a pixel clock is generated while being fixed to the second multiplication number when the reception quality indicated by the reception quality information at the time of generating is improved. apparatus. The acquisition means acquires the reception status information including reception channel information indicating a reception channel of the reception means,
The generating means may perform the first multiplication when a harmonic component of a pixel clock obtained by multiplying the resonance frequency by the first multiplication number is included in a frequency band corresponding to a reception channel indicated by the reception channel information. The projection apparatus according to claim 1, wherein a pixel clock is generated by switching a number to the second multiplication number. Further comprising a resolution conversion means for converting the resolution of the image signal that is the basis of the modulation of the light beam emitted by the emission means,
The resolution conversion means converts the resolution of the image signal so that the size of the image projected on the projection plane does not change according to the multiplication number by which the generation means multiplies the resonance frequency. The projection apparatus according to claim 1, wherein the projection apparatus is characterized. An emission unit that emits a light beam modulated based on an image signal, and a mirror element that reflects the light beam and scans it onto the projection surface, and is executed by a projection device that projects an image on the projection surface. Control method,
Generating a pixel clock having a frequency obtained by multiplying a resonance frequency of the mirror element by a first multiplication number as a pixel clock of an image signal that is a basis of modulation of the light beam emitted by the emission unit;
An acquisition step of acquiring reception status information indicating a reception status of a receiving means for receiving broadcast or communication;
With
The control method characterized in that the generating step generates a pixel clock by switching the first multiplication number to a second multiplication number in accordance with the reception status information. Projection apparatus for projecting an image on the projection surface, comprising: an emission unit that emits a light beam modulated based on an image signal; a mirror element that reflects the light beam and scans the projection surface; and a computer. A program executed by
Generating means for generating a pixel clock having a frequency obtained by multiplying a resonance frequency of the mirror element by a first multiplication number as a pixel clock of an image signal that is a basis of modulation of a light beam emitted by the emitting means;
An acquisition means for acquiring reception status information indicating a reception status of a reception means for receiving broadcast or communication;
Function the computer as
The generating means generates a pixel clock by switching the first multiplication number to a second multiplication number in accordance with the reception status information.

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