JP2011075948A - Image display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To select an appropriate laser from a plurality of lasers different in wavelength as a laser which emits a timing detection laser light to be detected by a light detection part. <P>SOLUTION: The image display which scans laser light emitted from lasers 63, 64, 65 having different wavelengths with a scanning part 30 includes: the light detection part 97 which is disposed at a position to which the laser light scanned with the scanning part 30 is made incident and outputs a BD signal based on the intensity of the incident laser light; and a driving control part 10 which allows a light source part 20 emit the timing detection laser light and makes the laser light incident to the light detection part 97, and controls the emitting timing of the laser light from the light source part 20 on the basis of the output timing of the BD signal from the light detection part 97. The deriving control part 10 detects the intensity variations of the laser light emitted from the plurality of lasers 63, 64, 65, respectively, and picks up the laser having the least intensity variation among the plurality of lasers 63, 64, 65 as the laser which emits the timing detection laser light. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image display device. More specifically, the present invention relates to an image display device that scans laser light emitted from a plurality of lasers having different wavelengths in a two-dimensional direction and projects the image onto a projection target to display an image.

  Conventionally, a scanning type in which laser beams emitted from a plurality of lasers having different wavelengths (for example, a red laser, a green laser, and a blue laser) are scanned in a two-dimensional direction by a scanning unit and projected onto a projection target to display an image. An image display device is known. As this type of scanning image display device, for example, a retinal scanning image display device and a screen scanning image display device are known. The retinal scanning image display apparatus uses a user's retina as a projection target, and the screen scanning image display apparatus uses a projection target as a screen.

  In the scanning image display device, a light detection unit is arranged on the scanning locus of the laser beam by the scanning unit, and based on the detection timing of the laser beam by the light detection unit, the laser beam from the laser that is the light source unit. The emission timing is adjusted (for example, refer to Patent Document 1).

JP 2009-086371 A

  The scanning image display device includes a plurality of lasers having different wavelengths such as a red laser, a green laser, and a blue laser, and a laser beam (hereinafter, referred to as a laser beam) that is detected by any one of these lasers. (Referred to as “timing detection laser light”).

  However, each of the plurality of lasers does not have the same deterioration characteristics, and if a laser that deteriorates quickly is set as a laser that emits timing detection laser light, the detection accuracy of the light detection unit increases with time. There is a risk of getting worse. Further, even when the timing detection laser beam is emitted from the laser having a slow deterioration, as a result of the replacement repair, the laser having the most deterioration may be a laser that emits the timing detection laser beam.

  Further, when an optical fiber cable or the like is provided between each laser and the light detection unit, for example, the carrying form of the optical fiber cable is changed by carrying the scanning image display device, and the waveguide according to the wavelength is changed. May cause efficiency fluctuations. At this time, if a laser beam having a wavelength whose waveguide efficiency greatly fluctuates is used as a timing detection laser beam, the detection accuracy in the light detection unit may be deteriorated.

  The present invention has been made in view of such problems, and it is possible to select an appropriate laser from a plurality of lasers having different wavelengths as a laser for emitting timing detection laser light to be detected by the light detection unit. An object of the present invention is to provide an image display device that can be used.

  In order to achieve the above object, the invention according to claim 1 scans the laser light emitted from the light source part in a two-dimensional direction, including a light source part including a plurality of lasers respectively emitting laser lights having different wavelengths. A scanning unit; a light detection unit arranged at a position where the laser beam scanned in the invalid scanning range of the scanning unit enters; and outputs a detection signal based on the intensity of the incident laser beam; and the scanning Projecting the laser beam scanned in the effective scanning range of the scanning range of the unit onto the projection target, projecting an image onto the projection target, and emitting the timing detection laser beam from the light source unit A control unit that controls the emission timing from the light source unit of the laser beam that is incident on the light detection unit and is scanned in the effective scanning range based on the detection signal output from the light detection unit, The controller detects intensity fluctuations of laser light respectively emitted from the plurality of lasers, and selects a laser having the smallest intensity fluctuation among the plurality of lasers as a laser for emitting the timing detection laser light. An image display device characterized by

  According to a second aspect of the present invention, in the image display device according to the first aspect, the control unit emits laser light from each of the lasers in an invalid scanning range of the scanning range of the scanning unit. The intensity of the light is detected by a light detection unit, and the fluctuation of the intensity of the laser light of each laser is detected based on the detection result of the light detection unit.

  According to a third aspect of the present invention, in the image display device according to the second aspect, the control unit emits laser beams having different wavelengths from the plurality of lasers with a predetermined intensity, and the light detection unit A correction process for correcting the detection value by multiplying the detection value of each laser beam by the photodetection unit by a coefficient corresponding to the spectral sensitivity of the photodetection unit. In addition, the intensity variation of each laser beam is detected from the temporal variation of the detection value corrected by the correction process.

  According to a fourth aspect of the present invention, in the image display device according to the second or third aspect of the present invention, the image display device further includes a storage unit that stores a corrected detection value every time the correction process is performed, and the control unit When correction processing is performed, a difference between the corrected detection value and the corrected detection value already stored in the storage unit is calculated for each laser beam, and the difference is the largest among the plurality of lasers. A laser that emits a small amount of laser light is a laser that has the least intensity variation.

  The invention according to claim 5 is the image display device according to claim 2 or 3, further comprising a storage unit that stores a first calculation result when the calculation process is performed for the first time. When calculation processing is performed, the difference between the calculation result and the first calculation result stored in the storage unit is calculated for each laser beam, and the laser beam having the smallest difference among the plurality of lasers is emitted. A laser is selected as a laser that emits the timing detection laser beam.

  According to a sixth aspect of the present invention, in the image display device according to the first aspect of the present invention, the controller controls the intensity of the laser light emitted from each laser based on a coefficient corresponding to the spectral sensitivity of the light detection unit. The laser light having the adjusted intensity is emitted from each of the lasers and is detected by the light detection unit, and the temporal variation of the detection value of the laser light of each laser by the light detection unit is detected. Thus, the intensity variation of the laser beam is detected.

  According to a seventh aspect of the present invention, in the image display device according to the first aspect, the light source unit includes a second light detection unit that detects the intensity of the laser light emitted from each of the lasers. The control unit emits laser beams having different wavelengths from the plurality of lasers in the invalid scanning range of the scanning range of the scanning unit, and causes the second light detection unit to detect the intensity of the laser beams. The intensity variation of the laser beam of each of the lasers is detected based on the detection result of the second light detection unit.

  According to an eighth aspect of the present invention, in the image display device according to any one of the first to seventh aspects, the plurality of lasers include at least a red laser and a laser of another color, and the control unit When selecting a laser that emits the timing detection laser beam, first, an intensity variation of the laser beam emitted from the red laser is detected, and if the detected intensity variation is within a set range, The red laser is selected as a laser for emitting the timing detection laser light without detecting intensity fluctuations of lasers of other colors.

  The invention according to claim 9 is the image display device according to any one of claims 1 to 8, further comprising notification means for notifying the failure of the laser, wherein the control unit When a laser whose intensity fluctuation exceeds a set range is detected among the lasers, it is determined that the laser exceeding the set range is a failure, and the failure of the laser is notified by the notification means.

  According to the present invention, it is possible to provide an image display device capable of selecting an appropriate laser among a plurality of lasers having different wavelengths as a laser for emitting timing detection laser light to be detected by a light detection unit. it can.

It is an external view of a retinal scanning image display apparatus. It is a figure which shows the electrical structure and optical structure of a retinal scanning-type image display apparatus. It is operation | movement explanatory drawing of the scanning part of a retinal scanning type image display apparatus. It is a figure which shows the structure of a photon detection part. It is a figure for demonstrating operation | movement of a photon detection part. It is explanatory drawing of each means with which CPU of a control part functions by executing a control program. It is a flowchart of the operation processing in a control part. It is a flowchart of the operation processing in a control part. It is a figure which shows the mode of integration of PD signal output from a photon detection part. It is explanatory drawing of the spectral sensitivity of a photon detection part. It is a flowchart of the operation processing in a control part. It is a flowchart of the other operation | movement process in a control part. It is a figure which shows the electrical structure and optical structure of another retinal scanning-type image display apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, a retinal scanning image display device that scans laser beams emitted from a plurality of lasers having different wavelengths, projects an image on at least one retina of a user, and displays the image is provided. The description will be given by way of example, but the present invention is not limited to this. For example, a screen scanning type image display device that scans laser beams with intensities emitted from lasers having different wavelengths and projects an image on a screen by scanning with a scanning unit. The present invention can be applied to other image display apparatuses.

[1. First Embodiment]
[1.1. Configuration of Retina Scanning Image Display Device]
First, the configuration of the retinal scanning image display apparatus (hereinafter referred to as “RSD”) according to the first embodiment will be specifically described with reference to FIGS. 1 and 2.

[1.1.1. Appearance of RSD1]
As shown in FIG. 1, the RSD 1 according to the present embodiment includes a control unit 2 and a head mounting tool 5, and the control unit 2 and the head mounting tool 5 are connected via a transmission cable unit 4. ing. The transmission cable unit 4 includes an optical fiber cable 50 (see FIG. 2) that transmits the laser light emitted from the control unit 2. Further, the transmission cable unit 4 includes a high-speed drive signal 61 and a low-speed drive for synchronizing with the light source unit 20 described later as well as the high-speed scanning unit 80 and the low-speed scanning unit 90 provided in the projection unit 6 described later. A drive signal transmission cable for transmitting the signal 62 is also provided.

  The control unit 2 generates an image signal S based on content information F stored in a built-in content storage unit 12 to be described later, and a laser beam having an intensity corresponding to the image signal S (hereinafter also referred to as “image light”). ) To the transmission cable section 4. Note that the control unit 2 can input an image signal, content information, and the like from an external input / output terminal (not shown). Here, the content information is composed of still image data, moving image data, and the like including a character image and a picture image.

  The head mounting tool 5 includes a projection unit 6 and a glasses-type frame 14 that supports the projection unit 6. The projection unit 6 scans the image light transmitted through the optical fiber cable 50 of the transmission cable unit 4 in a two-dimensional direction and projects the image light onto the user's eyes. Thereby, the image scanned in the two-dimensional direction is projected on the retina of the user's eye, and the user visually recognizes the image corresponding to the image signal S.

  The projection unit 6 is provided with a half mirror 15 at a position facing the user's eye 101. The external light La (see FIG. 2) passes through the half mirror 15 and enters the user's eye 101, and the image light Lb (see FIG. 2) emitted from the projection unit 6 is reflected by the half mirror 15 and reflected by the user's eye. 101 is incident. Thereby, the user can visually recognize the image by the image light Lb superimposed on the outside scene by the outside light La.

  As described above, the RSD 1 is a see-through type head mounted display that projects image light onto the user's eye 101 while transmitting external light.

[1.1.2. Electrical configuration and optical configuration of RSD1]
Next, the electrical configuration and optical configuration of the RSD 1 will be described with reference to FIG.

  The control unit 2 includes a drive control unit 10, a light source unit 20, and an operation unit 40.

  The drive control unit 10 includes a control unit 11 that controls the entire RSD 1, a content storage unit 12 that stores the content information F, and a drive signal supply circuit 13 that generates a signal that is an element for combining images. is doing.

  The control unit 11 controls the entire RSD 1 by executing predetermined processing described later according to a control program stored therein. The control unit 11 includes a CPU, a flash memory, a RAM, a VRAM, a plurality of input / output I / Fs, and the like, which are connected to a data communication bus, and transmit / receive various information via the bus. I do. In the following, the flash memory is an internal flash memory and the RAM is an internal RAM.

  The CPU is an arithmetic processing unit that operates each part of the RSD 1 by executing a control program stored in the flash memory, and executes various functions provided in the RSD 1. In addition, the CPU acquires information input from the operation unit 40 and performs processing according to the information. For example, the CPU converts the content information F into an image signal S of a predetermined format (for example, an NTSC composite signal, a component signal) based on information input from the operation unit 40 and outputs the image signal S to the drive signal supply circuit 13.

  Based on the image signal S, the drive signal supply circuit 13 generates each signal that is an element for forming an image in units of pixels. That is, the drive signal supply circuit 13 generates and outputs an R (red) drive signal 60r, a G (green) drive signal 60g, and a B (blue) drive signal 60b. The drive signal supply circuit 13 outputs a high-speed drive signal 61 used in the high-speed scanning unit 80 and a low-speed drive signal 62 used in the low-speed scanning unit 90, respectively.

  The light source unit 20 is provided with an R laser driver 66, a G laser driver 67, and a B laser driver 68. The R laser driver 66, the G laser driver 67, and the B laser driver 68 are based on the R drive signal 60r, the G drive signal 60g, and the B drive signal 60b output from the drive signal supply circuit 13, respectively. Drive currents are supplied to the laser 64 and the B laser 65, respectively. Each of the lasers 63, 64, 65 emits laser light (also referred to as “light beam”) whose intensity is modulated in accordance with the drive current supplied from each of the laser drivers 66, 67, 68. Each laser 63, 64, 65 can be configured as, for example, a semiconductor laser or a solid-state laser with a harmonic generation mechanism. If a semiconductor laser is used, the drive current can be directly modulated to modulate the intensity of the laser beam. However, if a solid-state laser is used, each laser is equipped with an external modulator, and the intensity of the laser beam is modulated. I do.

  Furthermore, the light source unit 20 is provided with collimating optical systems 71, 72, 73, dichroic mirrors 74, 75, 76 for combining the collimated laser beams, and a coupling optical system 77. The laser beams emitted from the lasers 63, 64, and 65 are collimated by collimating optical systems 71, 72, and 73, respectively, and then enter the dichroic mirrors 74, 75, and 76. Thereafter, these dichroic mirrors 74, 75, and 76 reflect and transmit the laser beams of the three primary colors selectively to reach the coupling optical system 77, and are combined and emitted to the optical fiber cable 50. Thus, the laser light emitted to the optical fiber cable 50 is the image light Lb, and is obtained by combining the laser light of each color whose intensity is modulated.

  The projection unit 6 is disposed between the light source unit 20 and the user's eye 101, and includes a scanning unit 30, a second relay optical system 95, and a light shielding unit 96 and a light detection unit 97 described later. The scanning unit 30 includes a collimating optical system 79, a high-speed scanning unit 80, a low-speed scanning unit 90, and a first relay optical system 85.

  The collimating optical system 79 collimates the laser light generated by the light source unit 20 and emitted through the optical fiber cable 50.

  The high-speed scanning unit 80 and the low-speed scanning unit 90 scan and scan in the first direction and the second direction so that the laser beam incident from the optical fiber cable 50 can be projected as an image onto the user's retina 101b. It is an optical system that uses a light beam. The high-speed scanning unit 80 reciprocally scans the incident laser light that has been collimated by the collimating optical system 79 in the first direction for image display. The low-speed scanning unit 90 scans in the first direction by the high-speed scanning unit 80 and scans the laser light incident via the first relay optical system 85 in the second direction substantially orthogonal to the first direction. Here, in the first direction and the second direction, the horizontal direction of the image to be displayed is the first direction and the vertical direction of the image to be displayed is the second direction, but the first direction is the vertical direction and the second direction. May be in the horizontal direction.

  The high-speed scanning unit 80 resonates the deflection element 81 having a deflection surface (reflection surface) 82 for scanning the laser light in the first direction, and resonates the deflection element 81 to shake the deflection surface 82 of the deflection element 81. A high-speed scanning drive circuit 83 that generates a drive signal to be moved based on the high-speed drive signal 61 is provided.

  On the other hand, the low-speed scanning unit 90 includes a non-resonance type deflection element 91 having a deflection surface (reflection surface) 92 for scanning laser light in the second direction, and the deflection surface 92 of the deflection element 91 is swung in a non-resonance state. A low-speed scanning drive circuit 93 that generates a drive signal to be moved based on the low-speed drive signal 62. The low-speed scanning unit 90 scans laser light for forming an image in the second direction from the first scanning line toward the last scanning line for each frame of the image to be displayed. Here, “scanning line” means one scanning in the first direction by the high-speed scanning unit 80.

  Here, galvanometer mirrors are used as the deflecting elements 81 and 91. However, as long as the deflecting surfaces 82 and 92 can be swung or rotated so as to scan the laser beam, piezoelectric driving or electromagnetic driving is possible. Any driving method such as electrostatic driving may be used. In this embodiment, a resonance type deflection element is used for the high-speed scanning unit 80 and a non-resonance type deflection element is used for the low-speed scanning unit 90. However, the present invention is not limited to this. For example, a resonance type deflection element may be used for the low-speed scanning unit 90, or both may be non-resonance type deflection elements.

  The first relay optical system 85 that relays the laser light between the high-speed scanning unit 80 and the low-speed scanning unit 90 converts the laser light scanned in the first direction by the deflection surface 82 of the deflection element 81 to the deflection element 91. It converges on the deflection surface 92. The laser beam is scanned in the second direction by the deflection surface 92 of the deflection element 91. The laser beam scanned by the deflection element 91 is transmitted by the half mirror 15 positioned in front of the eye 101 via the second relay optical system 95 in which two lenses 95a and 95b having positive refractive power are arranged in series. It is reflected and enters the user's pupil 101a. Thereby, an image corresponding to the image signal S is projected on the retina 101b, and the user recognizes the laser light (image light Lb) incident on the pupil 101a as an image. Further, the half mirror 15 transmits the external light La so as to enter the user's pupil 101a, so that the user can visually recognize an image in which an image based on the image light Lb is superimposed on an external scene based on the external light La. Can do.

  In the second relay optical system 95, the respective laser beams are made substantially parallel to each other by the lens 95a and converted into convergent laser beams. The laser beams are converted into substantially parallel laser beams by the lens 95b, and the center lines of these laser beams are converted so as to converge on the user's pupil 101a. In the present embodiment, a projection unit is configured by the lens 95b and the half mirror 15.

[1.2. Laser beam emission timing adjustment process]
Next, laser beam emission timing adjustment processing in the RSD 1 will be described.

[1.2.1. Laser beam emission timing]
3 shows the maximum scanning range G (the range formed by the high-speed scanning maximum range Xa and the low-speed scanning maximum range Ya shown in FIG. 3) and effective scanning by the deflection elements 81 and 91 of the high-speed scanning unit 80 and the low-speed scanning unit 90. The relationship with the range Z (the range formed by the high-speed effective scanning range X1 and the low-speed effective scanning range Y1 shown in FIG. 3) is shown. Here, the “maximum scanning range G” means the maximum range in which the deflection element 81 of the high-speed scanning unit 80 and the deflection element 91 of the low-speed scanning unit 90 can scan the laser beam.

  Among the maximum scanning range G, laser light (hereinafter referred to as “image forming laser”) that is intensity-modulated in accordance with the image signal S from the light source unit 20 at the timing when the scanning position by the deflection element 81 and the deflection element 91 is within the effective scanning range Z. Light ") is emitted. As a result, the image forming laser beam is scanned in the effective scanning range Z by the deflection element 81 and the deflecting element 91, and the image forming laser beam for one frame is scanned in the effective scanning range Z. This scanning is repeated for each frame image. The image forming laser beam scanned in the two-dimensional direction by the scanning unit 30 in this way is projected onto the user's retina 101 b via the second relay optical system 95 and the half mirror 15. Thereby, although the user responded to the image signal S, the image can be visually recognized. FIG. 3 virtually shows a locus γ of the laser beam scanned by the deflection element 81 and the deflection element 91 when it is assumed that the laser beam is always emitted from the light source unit 20. However, the number of scanning lines in the first direction X by the deflecting element 81 is about several hundreds or thousands per frame, and FIG. 3 simply shows the locus γ of the laser beam.

[1.2.2. Detection of scanning position of scanning unit 30]
In the scanning unit 30, the deflection surface 82 of the deflection element 81 is swung by the high speed drive signal 61 output from the high speed scan drive circuit 83, and the deflection of the deflection element 91 is performed by the low speed drive signal 62 output from the low speed scan drive circuit 93. The surface 92 is swung.

  However, the swing trajectories γ1 and γ2 (see FIG. 3) of the deflection surfaces 82 and 92 do not completely coincide with the signal waveforms of the drive signals 61 and 62, and a phase difference (jitter) or the like occurs. In particular, since the deflection element 81 is a resonance type deflection element that swings the deflection surface 82 at a high speed, the phase difference from the signal waveform of the high-speed drive signal 61 becomes large.

  Therefore, in the RSD 1 according to the present embodiment, as shown in FIGS. 2 and 3, the light detection unit 97 is arranged to detect the scanning timing of the laser light by the deflection surfaces 82 and 92. The drive control unit 10 of the RSD 1 adjusts the emission timing of the laser light for image formation from the light source unit 20 by causing the light detection unit 97 to detect the timing detection laser beam emitted from the light source unit 20.

  The light detection unit 97 is disposed at a position where the timing detection laser beam scanned in the invalid scanning range W outside the effective scanning range Z in the maximum scanning range G is incident. In addition, in order to prevent the timing detection light scanned outside the effective scanning range Z and the later-described intensity detection laser light from entering the user's eye 101 behind the light detection unit 97 in the invalid scanning range W. A light shielding portion 96 is provided. The light shielding unit 96 and the light detection unit 97 are disposed at the intermediate image plane position. For example, as illustrated in FIG. 2, the light shielding unit 96 may be a non-transmissive plate-like member having an opening in the effective scanning range Z in the maximum scanning range G at the intermediate image plane position.

  The drive control unit 10 emits timing detection laser light from the light source unit 20 and enters the light detection unit 97, and based on the detection timing of the timing detection laser light by the light detection unit 97, the light source of the image forming laser light The emission timing from the unit 20 is controlled.

  Here, it is assumed that an image forming laser beam for forming an image of 800 × 600 pixels in the effective scanning range Z is scanned, and an image of 1000 × 800 pixels can be formed in the maximum scanning range G at this time. Shall. It is assumed that 60 frames of images are formed per second.

  Since the deflection surface 92 of the deflecting element 91 swings 1/60 second and swings at a relatively low speed, the swing locus γ2 (see FIG. 3) of the deflection surface 92 is a low-speed drive signal 62. The phase difference produced between the two signal waveforms is small and the variation is small. For this reason, the drive control unit 10 emits the timing detection laser light from the light source unit 20 in consideration of the phase difference. In the present embodiment, the light detection unit 97 is arranged so as to straddle two or more continuous lines in consideration of variations.

  The deflection surface 82 of the deflecting element 81 swings for one line (one swing in the first direction) is 1 / 60,000 seconds, and swings at high speed. Further, the rocking locus γ1 (see FIG. 3) of the deflection surface 82 has a large phase difference from the signal waveform of the drive signal 62, and the variation thereof is also large. Furthermore, one line is for 800 pixels, and the readout time per pixel is ten and several nanoseconds. Moreover, since the deflection surface 82 oscillates in resonance, the oscillation angular velocity is not constant, and the time per pixel is the shortest at the oscillation center Y0 of the deflection surface 82.

  Therefore, in the RSD 1 according to this embodiment, in order to detect the scanning of the laser beam in the first direction by the deflecting surface 82 of the deflecting element 81 with higher accuracy, the laser beam scanned near the oscillation center of the deflecting surface 82 is detected. The light detection unit 97 is arranged at the incident position. Further, in order to improve the detection accuracy, the light detection unit 97 outputs a BD signal that rises when passing through a predetermined position N (see FIG. 5) of the light detection unit 97.

  FIG. 4 shows the configuration of the light detection unit 97. As shown in FIG. 4, the light detection unit 97 includes photodiodes PD1 and PD2, amplifiers AMP1 and AMP2, and a comparator COMP.

  When a current I1 flows through the photodiode PD1, the amplifier AMP1 outputs a voltage V1 corresponding to the current I1. The amplifier AMP1 has a reference voltage of + Va. Further, when the current I2 flows through the photodiode PD2, the amplifier AMP2 outputs a voltage V2 corresponding to the current I2. The amplifier AMP2 has a reference voltage of 0V.

  The outputs of the amplifiers AMP1 and AMP2 are input to the comparator COMP for comparison. The comparator COMP outputs a low level signal when the output of the amplifier AMP1 is higher than the output of the amplifier AMP2, and outputs a high level signal when the output of the amplifier AMP1 is equal to or lower than the output of the amplifier AMP2. When the current incident on the photodiodes PD1 and PD2 is small, a low level signal is output.

  Since the light detection unit 97 is configured as described above, for example, when laser light is scanned from the photodiode PD1 side to the photodiode PD2 side, the light detection unit 97 sets the scanning position of the laser light to a predetermined position N. When this happens, the BD signal that rises is output (see FIG. 5). The drive control unit 10 can detect the timing when the scanning position of the laser beam reaches the predetermined position N by inputting the BD signal. As described above, the light detection unit 97 uses the BD signal binarized with the threshold value corresponding to the amount of light incident on the photodiodes PD1 and PD2 as the signal corresponding to the intensity of the incident laser light, and the intensity of the incident laser light. A PD signal that changes according to the output is output.

[1.2.3. Selection of laser that emits laser light for timing detection]
The RSD 1 has a plurality of lasers having different wavelengths (R laser 63, G laser 64, and B laser 65), and a timing detection laser to be detected by the light detection unit 97 from any one of these lasers. Light is emitted.

  Each of the lasers 63, 64, 65 does not have the same deterioration characteristics. For this reason, as described above, for example, if a laser that deteriorates quickly is selected as a laser for emitting timing detection laser light, the detection accuracy of the light detection unit 97 may deteriorate. In addition, since the optical fiber cable 50 is provided between the lasers 63, 64, 65 and the light detection unit 97, the routing configuration of the optical fiber cable 50 changes according to the movement of the user's body. Waveguide efficiency varies according to the wavelength. At this time, if the laser light whose waveguide efficiency greatly fluctuates is used as the timing detection laser light, the detection accuracy in the light detection unit 97 may be deteriorated as in the case of deterioration.

  Therefore, in the RSD 1 of the present embodiment, the laser with the smallest intensity variation is selected from the plurality of lasers 63, 64, 65 having different wavelengths as the laser for emitting the timing detection laser light to be detected by the light detection unit 97. is doing.

  Hereinafter, processing for detecting intensity fluctuations of the laser beams of the lasers 63, 64, and 65 will be described with reference to FIGS. This detection process is a process executed when an image display operation is performed by a user operation on the operation unit 40.

  The intensity fluctuations of the laser beams of the lasers 63, 64, 65 are detected by the control unit 11. In this control unit 11, the CPU executes a control program stored in the flash memory. Thereby, as shown in FIG. 6, the control unit 11 functions as a PD signal output voltage integration unit 110, a sensitivity correction unit 111, an integral value variation calculation unit 113, a variation integral value comparison unit 114, and the like, and integrates the internal RAM. A laser that functions as the value storage unit 112 or the like and emits a timing detection laser is selected.

  The following process is a process performed by the CPU of the control unit 11, and is executed by the CPU of the control unit 11 using an internal flash memory or an internal RAM. Further, it is assumed that the control unit 11 drives the scanning unit 30 by outputting a control signal to the drive signal supply circuit 13. At this time, the drive signal supply circuit 13 swings the deflecting surface 82 of the deflecting element 81 and the deflecting surface 92 of the deflecting element 91 so that the trajectory of the scanning position of the scanning unit 30 becomes the trajectory γ shown in FIG. I have control.

  When the image display process is started, the control unit 11 sets a PD value acquisition period as shown in FIG. 7 (step S10). The PD value acquisition period is information stored in the internal flash memory, and the CPU of the control unit 11 reads the PD value acquisition period information from the internal flash memory and stores it in the internal RAM. The PD value acquisition period information can be changed by a user operation on the operation unit 40.

  Next, the control unit 11 performs a PD value acquisition process for acquiring an R-PD value, a G-PD value, and a B-PD value (step S11). This PD value acquisition process is a process from steps S20 to S27 shown in FIG. 8, and will be described in detail later.

  Next, the control unit 11 uses the R-PD value, the G-PD value, and the B-PD value, that is, a laser that emits timing detection laser light (hereinafter, “timing detection laser”). Is also determined (step S12).

  Thereafter, the control unit 11 drives the drive signal supply circuit 13 to drive the laser determined in step S12 to perform BD signal acquisition processing (step S13). Based on the control signal from the control unit 11, the drive signal supply circuit 13 determines the laser (hereinafter, “timing detection laser”) determined in step S 12 when the scanning position of the scanning unit 30 is in the invalid scanning range W. The timing detection laser light is emitted from the light detection unit 97 and a BD signal output from the light detection unit 97 is acquired. For example, it is assumed that the light detection unit 97 is arranged across the 20th line and the 25th line from the top line of the maximum scanning range G as described above. At this time, when the scanning position of the scanning unit 30 reaches the 20th line, the control unit 11 controls the drive signal supply circuit 13 to start emitting timing detection laser light from the timing detection laser. Then, the control unit 11 controls the drive signal supply circuit 13 immediately before the scanning position of the scanning unit 30 reaches the 26th line, and stops emission of the timing detection laser beam from the timing detection laser. The control unit 11 acquires BD signals sequentially output from the light detection unit 97 when the timing detection laser beam is emitted from the timing detection laser. The drive signal supply circuit 13 determines the emission timing of the image forming laser light with reference to the rising edge of the BD signal output from the light detection unit 97.

  Next, the control unit 11 performs image display processing (step S14). This image display processing is performed by the control unit 11 reading the content information F from the content storage unit 12, generating the image signal S, and inputting it to the drive signal supply circuit 13. When the image signal S is input, the drive signal supply circuit 13 generates an R drive signal 60r, a G drive signal 60g, and a B drive signal 60b based on the determined emission timing of the image forming laser light, and the laser drivers 66 and 67. , 68 respectively. As a result, when the scanning position of the scanning unit 30 is within the effective scanning range Z, the laser light for image formation whose intensity is modulated in accordance with the image signal S is emitted from each of the lasers 63, 64, 65. It is scanned and projected onto the retina 101b of the user's eye 101.

  When the process of step S14 ends, the CPU of the control unit 11 determines whether or not the PD value acquisition timing has come based on the PD value acquisition period information stored in the internal RAM (step S15). The PD value acquisition timing is generated every predetermined period (for example, 1 hour). In addition, a temperature detection unit may be provided, and it may be determined that the PD value acquisition timing has been reached when there is a predetermined temperature fluctuation. If it is determined that the PD value acquisition timing has come (step S15: YES), the control unit 11 proceeds to step S11.

  On the other hand, if it is determined that the PD value acquisition timing has not come (step S15: NO), the control unit 11 detects an end instruction (step S16). When determining that the display end instruction has been detected (step S16: Yes), the control unit 11 ends the image display process. On the other hand, when determining that the display end instruction has not been detected (step S16: No), step S13 is performed. Repeat the process from.

  Next, the PD value acquisition process in step S11 will be described with reference to FIG.

  When this PD value acquisition process is started, the control unit 11 controls the drive signal supply circuit 13 to emit laser light with a predetermined intensity (hereinafter referred to as “intensity detection laser light”) from the R laser 63 (step S20). ). For example, it is assumed that the light detection unit 97 is arranged across the 20th line and the 25th line from the top line of the maximum scanning range G. At this time, when the scanning position of the scanning unit 30 reaches the 20th line, the control unit 11 controls the drive signal supply circuit 13 to start emission of intensity detection laser light from the R laser 63. Thereafter, the control unit 11 controls the drive signal supply circuit 13 immediately before the scanning position of the scanning unit 30 reaches the 22nd line, and stops emission of the intensity detection laser light from the R laser 63.

As shown in FIG. 9, the control unit 11, as the PD signal output voltage integrating unit 110, outputs PD signals (R−) sequentially output from the light detection unit 97 according to the intensity detection laser light emitted from the R laser 63. The voltage V _R of the PD signal) is integrated (step S21).

Next, when the scanning position of the scanning unit 30 reaches the 22nd line, the control unit 11 controls the drive signal supply circuit 13 to emit intensity detection laser light from the G laser 64 (step S22). integrating the voltage V _G of the PD signals sequentially outputted from the light detection unit 97 (G-PD signal) in response to the the strength detection laser light emitted from the (step S23). Thereafter, the control unit 11 stops the emission of the intensity detection laser beam from the G laser 64 by controlling the drive signal supply circuit 13 immediately before the scanning position of the scanning unit 30 reaches the 24th line. .

Next, when the scanning position of the scanning unit 30 reaches the 24th line, the control unit 11 controls the drive signal supply circuit 13 to start emission of intensity detection laser light from the B laser 65 (step S24). The voltage V _B of the PD signal (B-PD signal) sequentially output from the light detection unit 97 according to the intensity detection laser beam emitted from the laser 65 is integrated (step S25). Thereafter, the control unit 11 controls the drive signal supply circuit 13 immediately before the scanning position of the scanning unit 30 reaches the 26th line, and stops emission of the intensity detection laser light from the B laser 65.

As described above, the integrated values ∫V _R dt, ∫V _G dt, and ∫V _B dt of the voltages of the detected PD signals are obtained when the intensity detection laser beams are emitted from the lasers 63, 64, and 65 with the same intensity. But they are different. This is because the light detection unit 97 has, for example, the spectral sensitivity shown in FIG. 10, and the detection sensitivity of the laser light in the light detection unit 97 differs depending on the wavelength.

Therefore, the control unit 11 uses, as sensitivity correction means, light to the integrated values ∫V _R dt, ∫V _G dt, and ∫V _B dt of the voltages of the PD signals corresponding to the R, G, and B intensity detection laser beams. The sensitivity coefficients K _R , K _G , and K _B corresponding to the spectral sensitivity of the detection unit are multiplied (step S26). The values K _R ∫V _R dt, K _G ∫V _G dt, and K _B ∫V _B dt thus multiplied are referred to as R-PD value, G-PD value, and B-PD value, respectively.

When the light detection unit 97 has, for example, the spectral sensitivity shown in FIG. 10, when the laser beam for intensity detection is emitted from each laser with the same intensity, the voltage level of the PD signal is R: G: B≈1: 5:10. Therefore, the reciprocal of the voltage level of the PD signal is used as a sensitivity coefficient corresponding to the spectral sensitivity of the light detection unit. For example, the sensitivity coefficient K _R = 10 for red laser light, the sensitivity coefficient K _{G for} green laser light = 5, and the sensitivity coefficient K _B = 1 for blue laser light.

The control unit 11 integrates the calculated R-PD value (K _R ∫V _R dt), G-PD value (K _G ∫V _G dt), and B-PD value (K _B ∫V _B dt). The data is stored in the internal RAM 112 (step S27). In this way, the control unit 11 uses the detection coefficient ∫V _R dt, ∫V _G dt, and ∫V _B dt of each laser beam by the light detection unit 97, and the sensitivity coefficient K _R corresponding to the spectral sensitivity of the light detection unit 97, respectively. performs correction processing for correcting the detection value by multiplying the K _G, K _B.

  Next, with reference to FIG. 11, the used laser determination process in step S12 will be described.

  When the used laser determining process is started, the control unit 11 stores the previously stored R-PD value, G-PD value, B-PD value and the currently stored R-PD value, G- Read PD value and B-PD value. Then, the control unit 11 serves as the integral value fluctuation calculating means 113 to calculate the difference ΔR between the previously stored R-PD value and the currently stored R-PD value, the previously stored G-PD value, and the currently stored G-PD value. The difference ΔG, the difference ΔB between the B-PD value stored last time and the B-PD value stored this time are calculated (step S30).

  Next, the control unit 11 determines whether or not the differences ΔR, ΔG, ΔB exceed the limit values as the fluctuation integration value comparison unit 114 (step S31). When the differences ΔR, ΔG, ΔB exceed the limit values (step S31: YES), the control unit 11 reads the content information F for displaying that the laser is out of order from the content storage unit 12, and outputs it to the image signal S. The signal is converted and output to the drive signal supply circuit 13 (step S38). Thereafter, the control unit 11 ends the display process. Thus, an image indicating that the laser is out of order is projected onto the retina 101b of the user's eye, and the user can grasp that the laser is out of order. Note that as the notification means, for example, a speaker may be provided in the control unit 2 or the head-mounted device 5, and the control unit 11 may notify that the laser is out of order by sound from the speaker. Further, an abnormality notification LED may be provided in the control unit 2 or the head-mounted device 5, and the control unit 11 may notify that the laser is out of order by lighting or blinking the abnormality notification LED. Thus, by notifying that the laser is out of order as an image but notifying the speaker or the abnormality notification LED, it is possible to notify without using the failed laser. Furthermore, after notifying that the laser is out of order, the control unit 11 prevents the light source unit 20 from generating laser light, thereby preventing the user from displaying an image with degraded quality. it can. Further, an interface with the network may be provided, and the control unit 11 may notify a predetermined server of the failure using this interface. In this way, it is possible to respond more quickly to a failure.

  When none of the differences ΔR, ΔG, and ΔB exceeds the limit value (step S31: NO), the control unit 11 determines whether or not the difference ΔR is smaller than the difference ΔG as the fluctuation integral value comparison unit 114 (step S31: NO). Step S32). If it determines with difference (DELTA) R being smaller than difference (DELTA) G (step S32: YES), the control part 11 will determine whether difference (DELTA) R is smaller than difference (DELTA) B as the fluctuation | variation integral value comparison means 114 (step S33). If it determines with difference (DELTA) R being smaller than difference (DELTA) B (step S33: YES), the control part 11 will determine as a laser which uses R laser 63 (step S34), and will end use laser determination processing.

  If it is determined in step S32 that the difference ΔR is not smaller than the difference ΔB (step S33: NO), the control unit 11 determines that the B laser 65 is used (step S35), and ends the used laser determination process. To do.

  Further, when it is determined in step S32 that the difference ΔR is not smaller than the difference ΔG (step S32: NO), the control unit 11 determines whether or not the difference ΔB is smaller than the difference ΔG as the fluctuation integration value comparison unit 114. Determination is made (step S36). If it determines with difference (DELTA) B being smaller than difference (DELTA) G (step S36: YES), the control part 11 will determine as a laser which uses B laser 65 (step S35), and will complete | finish a use laser determination process. On the other hand, if it determines with the difference (DELTA) B not being smaller than the difference (DELTA) G (step S36: NO), the control part 11 will determine as a laser which uses the G laser 64 (step S37), and will complete | finish a use laser determination process.

  In this way, the control unit 11 emits laser beams having different wavelengths from the plurality of lasers 63, 64, 65, respectively, and causes the light detection unit 97 to detect their intensities. Then, the control unit 11 performs a correction process for correcting the detection value by multiplying the detection value of each laser beam by the light detection unit 97 by a sensitivity coefficient corresponding to the spectral sensitivity of the light detection unit 97. Furthermore, the control unit 11 detects the intensity variation of each laser beam from the temporal variation of the detection value corrected by the correction process for each laser beam. Therefore, it is possible to detect fluctuations in the laser beams of the lasers 63, 64, 65 by the light detection unit 97 that detects the timing detection laser light. As a result, for example, a laser beam whose waveguide efficiency largely varies when the routing configuration of the optical fiber cable 50 changes due to the movement of the RSD 1 or the like can be used as the timing detection laser beam.

  In the above embodiment, when performing the correction process, the control unit 11 calculates, for each laser beam, the difference between the corrected detection value and the previous corrected detection value stored in the internal RAM for each laser beam. However, the present invention is not limited to this. For example, the intensity fluctuations of the lasers 63, 64, 65 may be detected with reference to the corrected detection value stored in the internal RAM when the RSD 1 is manufactured. In this case, in step S30, the corrected detection value stored in the internal RAM at the time of manufacturing the RSD 1 is used as the first calculation value, and these are compared with the detection value after correction this time. By doing so, it is possible to detect the intensity fluctuation from the initial value, and it is possible to more accurately detect the intensity fluctuation of the laser that deteriorates over time. It should be noted that the first calculation value may be the first calculation value, not the time of manufacture, but the first calculation value every time RSD 1 is started. In the above embodiment, the correction process is periodically performed at a predetermined timing. However, the correction process may be performed only when the RSD 1 is activated. In this case, when the process of step S14 is completed, the process proceeds to step S16 without performing the process of step S15.

  Further, in the above-described embodiment, laser light for intensity detection having a constant intensity is emitted from each of the lasers 63, 64, 65, and the PD signal output from the light detection unit 97 is corrected according to the spectral sensitivity of the light detection unit 97. I did it, but it is not limited to this. For example, the PD signal correction for the intensity detection laser light emitted from the laser 63 is not performed, and the PD signal correction for the intensity detection laser light emitted from the lasers 64 and 65 is performed according to the spectral sensitivity of the light detection unit 97. May be performed.

Further, the laser light whose intensity has been corrected according to the spectral sensitivity of the light detection unit 97 is emitted from each of the lasers 63, 64, 65, and the PD signal output from the light detection unit 97 is not corrected. You can also. In this case, the control unit 11 adjusts the intensity of the laser light emitted from each of the lasers 63, 64, 65 based on the sensitivity coefficient corresponding to the spectral sensitivity of the light detection unit 97, and uses the laser light whose intensity has been adjusted for each laser 63. , 64, 65 to be detected by the light detector 97. And the control part 11 detects the intensity fluctuation | variation of the laser beam of each color by detecting the time fluctuation | variation of the detected value of the laser beam of each laser 63,64,65 by the light detection part 97. FIG. For example, the intensity of the laser light is emitted from each of the lasers 63, 64, 64 as R: G: B = K _R : K _G : K _B.

  In the above description, it is assumed that the loss for each laser beam is the same on the optical path from each laser 63, 64, 65 to the light detection unit 97, except for changes due to the routing state of the optical fiber cable 50. The loss is not limited to this, and the loss may vary depending on the wavelength. In this case, it is possible to cope with the loss difference by adjusting the coefficient for correcting the integral value of the PD signal or by adjusting the intensity of the laser light emitted from the lasers 63, 64, 65.

[2. Second Embodiment]
In the first embodiment, the intensity variation of the laser light emitted from each of the lasers 63, 64, 65 is detected. In the RSD of the second embodiment, first, the laser emitted from the R laser 63 is used. Detects fluctuations in light intensity. If the detected intensity fluctuation is within the set range, the R laser 63 is selected as the timing detection laser without detecting the intensity fluctuation of the lasers 64 and 65 of other colors. This will be specifically described below. The RSD 1 of the first embodiment differs from the RSD 1 only in a part of the control program stored in the internal flash memory, and the rest of the configuration is the same, and will be described using the same reference numerals as those of the first embodiment.

  When the image display process is started, the control unit 11 sets a PD difference allowable value as shown in FIG. 12 (step S50). This PD difference allowable value is information stored in the internal flash memory, and the CPU of the control unit 11 reads the PD difference allowable value from the internal flash memory and stores it in the internal RAM. The PD difference allowable value can be changed by a user operation on the operation unit 40. At this time, for safety, it is better to set a range that can be changed by the user at the time of shipment.

  Next, the control unit 11 sets a PD value acquisition period and acquires only the R-PD value (steps S51 and S52), similarly to the processes in steps S10, S20, and S21 of the first embodiment.

  Next, the control unit 11 reads the previously stored R-PD value and the currently stored R-PD value in the internal RAM which is the integral value storage unit 112. And the control part 11 calculates the difference (DELTA) R of the R-PD value memorize | stored last time and the R-PD value memorize | stored this time as the integral value fluctuation | variation calculation means 113, respectively (step S53).

  Thereafter, the control unit 11 determines whether or not the difference ΔR is smaller than the PD difference allowable value as the fluctuation integration value comparison unit 114 (step S54). When it is determined that the difference ΔR is smaller than the PD difference allowable value (step S54: YES), the control unit 11 determines that the R laser 63 is used (step S55), and ends the use laser determination process (step S54). S55).

  On the other hand, if it is determined that the difference ΔR is not smaller than the PD difference allowable value (step S53: NO), the control unit 11 starts a use laser determination process (step S56). This use laser determination process is the same process as the process of step S12 of the first embodiment. That is, the intensity fluctuation of the laser light emitted from each of the lasers 63, 64, 65 is detected, and the laser with the smallest intensity fluctuation is determined as the laser emitting the timing detection laser light.

  Then, the control part 11 performs the process similar to the process of step S13-S16 of 1st Embodiment (step S57-S60).

  As described above, the control unit 11 detects the intensity variation of the laser light emitted from the R laser 63, and does not detect the intensity variation of the other lasers 64 and 65 if the intensity variation is within the set range. The R laser 63 is selected as the timing detection laser.

  Since the quality of the R laser 63 is stable and the deterioration speed is slow, first, the intensity fluctuation of the R laser 63 is detected. If the intensity fluctuation is within a predetermined range, the intensity fluctuations of the other lasers 64 and 65 are detected. Do not detect. As a result, the power consumption can be reduced, and the processing load due to the used laser determination process can be reduced.

  When the lasers 63, 64, and 65 have a stable quality and little deterioration are the G (green) laser 64 and the B (blue) laser 65, the laser has a stable quality and little deterioration instead of the R laser 63. If the intensity fluctuation is within a predetermined range, the intensity fluctuation of other lasers is not detected.

[3. Other Embodiments]
In the first and second embodiments, the intensity detection laser beam is detected by the light detection unit 97, but the present invention is not limited to this. For example, as shown in FIG. 13, an R detection unit 51, a G detection unit 52, and a B detection unit 53 are provided as second light detection units in the vicinity of the emission ports of the lasers 63, 64, 65, and these detection units 51 are provided. , 52, 53 may detect the intensity detecting laser beam. In the RSD 1 ′ shown in the figure, the intensity variation of the laser light emitted from each laser 63, 64, 65 based on the intensity of each laser light detected by the R detection unit 51, the G detection unit 52, and the B detection unit 53. Is detected. In the case where a laser incorporating a light detection unit is used as the lasers 63, 64, 65, the built-in light detection unit can be used as the second light detection units 51, 52, 53.

'In, each correction coefficient to the integral value of the voltage of the PD signal output from the detector 51, 52, 53 K _R' RSD 1 13 performs a correction process by multiplying the, K _G ', K _B'.

For example, the intensity of the laser light emitted from each of the lasers 63, 64, and 65 is L _R , L _G , and L _B, and the detection sensitivities of the detection units 51, 52, and 53 are X _R , X _G , and X _B. At this time, the correction coefficients K _R ′, K _G ′, and K _B ′ are 1 / L _R X _R , 1 / L _G X _G , and 1 / L _B X _B , respectively.

Note that by the _{1 / L R X R = 1} / L G X G = 1 / L B X B, the control unit 11, the correction coefficient K _R ', K _G', without using a K _B ', Intensity fluctuations of the lasers 63, 64, 65 can be detected, and the processing load can be reduced.

  Moreover, in the said embodiment, although the light detection part 97 was arrange | positioned in the optical path after scanning in the two-dimensional direction by the scanning part 30, it is not restricted to this. For example, a half mirror is disposed on the optical path after the laser beam is scanned in the first direction by the high-speed scanning unit 80, and the light detection unit 97 ′ is disposed at a position where the light reflected by the half mirror is incident. Also good. In this case, the laser light transmitted through the half mirror is scanned in the second direction by the low-speed scanning unit 90 via the first relay optical system 85. Even in this case, the control unit 11 detects the timing from the light source unit 20 when the scanning position of the scanning unit 30 is in the invalid scanning range so that the timing detection laser beam does not enter the user's eye. A laser beam is emitted. Accordingly, in this case as well, as described above, the light detection unit 97 ′ is disposed at a position where the laser beam scanned in the invalid scanning range G in the scanning range of the scanning unit 30 is incident.

  In the above description, an example in which lasers of three primary colors (R laser 63, G laser 64, and B laser 65) are used has been described. However, the present invention is not limited to this. For example, lasers of different colors, two or four or more The same applies to the case of using the above laser.

  Although the present invention has been described through the above-described embodiments, the following effects can be expected according to this embodiment.

  (1) In the RSD 1, 1 ′ according to the present embodiment, the light source unit 20 including a plurality of lasers 63, 64, and 65 that respectively emit laser beams having different wavelengths and the laser beam emitted from the light source unit 20 are two-dimensionally displayed. BD signal (detection signal) based on the intensity of the incident laser beam, which is disposed at a position where the scanning unit 30 that scans in the direction and the laser beam scanned in the invalid scanning range W of the scanning range G of the scanning unit 30 is incident Projecting the laser beam for image formation scanned in the effective scanning range Z in the scanning range G of the scanning unit 30 onto the retina of the user's eye, which is the projection target, Based on a BD signal (detection signal) output from the light detection unit 97, a timing detection laser beam is emitted from the light source unit 20 and the lens 95b that projects an image on the retina. range In and a drive control unit 10 that controls the emission timing of the light source unit 20 of the laser beam for image formation to be scanned. Then, the drive control unit 10 detects the intensity variation of the laser light emitted from each of the plurality of lasers 63, 64, 65, and detects the timing of the laser having the smallest intensity variation among the plurality of lasers 63, 64, 65. This is selected as a laser that emits laser light for use. Therefore, an appropriate laser can be selected from a plurality of lasers having different wavelengths as lasers for emitting timing detection laser light to be detected by the light detection unit, and the timing detection laser light in the light detection unit can be selected. Deterioration of detection accuracy can be prevented.

  (2) Further, the drive control unit 10 emits laser beams from the lasers 63, 64, 65 in the invalid scanning range W of the scanning range G of the scanning unit 30, and detects their intensities by the light detection unit 97. Then, based on the detection result by the light detection unit 97, the intensity variation of the laser light of each laser 63, 64, 65 is detected. Therefore, it is possible to detect the fluctuation of the laser light of each laser in the light detection section that actually detects the timing detection laser light. For example, the movement of the RSD 1, 1 ′, carrying, external vibration, etc. When the routing configuration changes, the waveguide efficiency may vary depending on the wavelength. However, it is possible to suppress the laser beam whose waveguide efficiency greatly varies from being a timing detection laser beam. It is possible to prevent the detection accuracy from deteriorating.

(3) Further, the drive control unit 10 emits laser beams having different wavelengths from the plurality of lasers 63, 64, 65, respectively, and causes the light detection unit 97 to detect their intensities. detection values of the laser light by the _{(∫V R dt, ∫V G dt} , ∫V B dt) detection value by multiplying the coefficient corresponding to the spectral sensitivity of each light detection section 97 (∫V _R dt, ∫V Correction processing for correcting ( _G dt, ∫V _B dt) is performed, and intensity fluctuations of the respective laser beams are detected from temporal variations (ΔR, ΔG, ΔB) of detection values corrected by the correction processing for each laser beam. Therefore, even if the detection sensitivity at the light detection unit varies depending on the wavelength, the intensity fluctuation of each laser beam can be compared in the same range, so that it is easy to select the laser that emits the timing detection laser beam. It can be carried out.

  (4) Further, an internal RAM (storage unit) that stores the corrected detection value every time correction processing is performed, and when the correction processing is performed, the drive control unit 10 detects the corrected detection value and the internal value. The difference (ΔR, ΔG, ΔB) from the corrected detection value already stored in the RAM (storage unit) is calculated for each laser beam, and the difference (ΔR, ΔG, A laser that emits a laser beam with the smallest ΔB) is a laser with the least intensity fluctuation. By doing so, the intensity fluctuation can be detected by storing the previous detection result, and the intensity fluctuation can be easily detected. Further, by storing the detection results up to a plurality of times before, it is possible to grasp the transition of the intensity fluctuation, and to perform the intensity fluctuation detection with higher accuracy. For example, even if the detection level of the laser beam becomes abnormally high or low due to a temporary cause, the intensity fluctuation detection can be made more accurate by averaging the detection results obtained several times before. It can be carried out. In addition, by utilizing the time history data of laser intensity fluctuations, for example, bandpass filter processing is performed to see only the vicinity of the frequency of external vibration that occurs when a person walks, thereby identifying the fluctuation factors and presenting countermeasures. If this is done, it is possible to obtain timing signals that are more resistant to fluctuations.

  (5) In addition, a flash memory (storage unit) that stores the first calculation result when the calculation process is performed for the first time is provided, and when the calculation process is performed, the drive control unit 10 The difference (ΔR, ΔG, ΔB) from the first calculation result stored in the storage unit) is calculated for each laser beam, and the laser having the smallest difference (ΔR, ΔG, ΔB) among the plurality of lasers 63, 64, 65. A laser that emits light is selected as a laser that emits laser light for timing detection. By doing so, it is possible to detect the intensity fluctuation from the initial value, and it is possible to more accurately detect the intensity fluctuation of the laser that deteriorates over time.

  (6) Further, the intensity of the laser light emitted from each of the lasers 63, 64, 65 is adjusted based on the coefficients corresponding to the spectral sensitivities of the drive control unit 10 and the light detection unit 97, and each of the laser beams whose intensity has been adjusted is adjusted. Each laser beam is emitted by being emitted from each of the lasers 63, 64, 65 and detected by the light detection unit 97, and by detecting temporal variations in the detection values of the laser beams of the lasers 63, 64, 65 by the light detection unit. Detects intensity fluctuations. Therefore, even if the detection sensitivity at the light detection unit varies depending on the wavelength, the intensity fluctuation of each laser beam can be compared in the same range, so that it is easy to select the laser that emits the timing detection laser beam. It can be carried out.

  (7) The light source unit 20 ′ further includes second light detection units 51, 52, and 53 that detect the intensity of the laser light emitted from each of the lasers 63, 64, and 65. The drive control unit 10 includes: In the scanning range G of the scanning unit 30, laser beams having different wavelengths are emitted from the plurality of lasers 63, 64, 65 in the invalid scanning range W, and the intensities thereof are output by the second light detection units 51, 52, 53. Based on the detection results of the second light detectors 51, 52, 53, the intensity fluctuations of the laser beams of the lasers 63, 64, 65 are detected. As described above, since the light detection unit for detecting each laser beam is provided, by adjusting the detection sensitivity of each light detection unit, it is possible to detect fluctuations in the intensity of each laser beam without performing correction processing. The processing load due to the laser used determination process can be reduced.

  (8) The plurality of lasers include at least an R (red) laser 63 and lasers 64 and 65 of other colors, and the drive control unit 10 selects a laser that emits timing detection laser light. First, the intensity fluctuation of the laser beam emitted from the R laser 63 is detected, and if the detected intensity fluctuation is within the set range, the intensity fluctuations of the lasers 64 and 65 of other colors are not detected. The R laser 63 is selected as a laser for emitting timing detection laser light. The R laser 63 has a stable quality and a slow deterioration rate. Accordingly, if the intensity fluctuation of the R laser 63 is within the predetermined range, the power consumption can be reduced by detecting the intensity fluctuation of the other lasers 64 and 65, and the laser used. The processing load due to the determination process can be reduced.

  (9) In addition, a notification means (for example, a speaker or an abnormality notification LED) for notifying the failure of the lasers 63, 64, 65 is provided, and the drive control unit 10 has the intensity of the plurality of lasers 63, 64, 65. When a laser whose fluctuation exceeds the set range is detected, it is determined that the laser exceeding the set range is a failure, and the failure of the laser is notified by the notification means. Therefore, it is possible to detect a laser failure only by adding a process for determining whether the intensity fluctuation of the laser light exceeds the set range, and further providing a notification means to notify the user of the laser failure. Can do.

1 Retina scanning image display (RSD)
DESCRIPTION OF SYMBOLS 10 Drive control part 11 Control part 20 Light source part 30 Scan part 40 Operation part 50 Optical fiber cable 63 R laser 64 G laser 65 B laser 97 Photodetection part

Claims (9)

A light source unit including a plurality of lasers each emitting laser light having different wavelengths;
A scanning unit that scans the laser beam emitted from the light source unit in a two-dimensional direction;
A light detection unit arranged at a position where the laser beam scanned in the invalid scanning range of the scanning unit is incident, and outputs a detection signal based on the intensity of the incident laser beam;
A projection unit that projects the laser beam scanned in an effective scanning range of the scanning unit to the projection target and projects an image on the projection target;
A laser beam for timing detection is emitted from the light source unit, is incident on the light detection unit, and is scanned from the light source unit of the laser light scanned in the effective scanning range based on the detection signal output from the light detection unit. A control unit for controlling the emission timing of
The control unit detects intensity fluctuations of laser beams respectively emitted from the plurality of lasers, and selects a laser having the smallest intensity fluctuation among the plurality of lasers as a laser for emitting the timing detection laser lights. An image display device characterized by the above.   The control unit emits laser beams from the lasers in the invalid scanning range of the scanning range of the scanning unit, detects the intensity of the laser beams in the light detection unit, and based on the detection result of the light detection unit The image display apparatus according to claim 1, wherein a fluctuation in intensity of laser light of each of the lasers is detected.   The control unit emits laser beams having different wavelengths from the plurality of lasers with predetermined intensities, detects the intensities thereof with the light detection unit, and sets the detection values of the laser beams by the light detection unit, respectively. A correction process for correcting the detection value by multiplying by a coefficient corresponding to the spectral sensitivity of the light detection unit is performed, and the intensity of each laser beam is determined from the temporal variation of the detection value corrected by the correction process for each laser beam. The image display apparatus according to claim 2, wherein a fluctuation is detected. A storage unit that stores the corrected detection value every time the correction process is performed,
The control unit, when performing the correction process, calculates a difference between the corrected detection value and the corrected detection value already stored in the storage unit for each of the laser beams, and 4. The image display device according to claim 2, wherein a laser that emits a laser beam having the smallest difference is a laser having the least intensity fluctuation. 5. A storage unit for storing the first calculation result when the calculation process is performed for the first time,
When the control unit performs the calculation process, the control unit calculates a difference between the calculation result and the first calculation result stored in the storage unit for each laser beam, and the difference is the largest among the plurality of lasers. The image display apparatus according to claim 2 or 3, wherein a laser that emits a small amount of laser light is selected as a laser that emits the timing detection laser light.   The control unit adjusts the intensity of the laser beam emitted from each laser based on a coefficient corresponding to the spectral sensitivity of the light detection unit, and emits the laser beam with the adjusted intensity from each of the lasers. 2. The intensity variation of the laser beam is detected by detecting by a light detection unit and detecting a temporal variation of a detection value of the laser beam of each laser by the light detection unit. Image display device. The light source unit includes a second light detection unit that detects the intensity of laser light emitted from each laser,
The control unit emits laser beams having different wavelengths from the plurality of lasers in an invalid scanning range of the scanning range of the scanning unit, and causes the second light detection unit to detect the intensity of the laser beams, The image display device according to claim 1, wherein a fluctuation in the intensity of the laser light of each laser is detected based on a detection result by the light detection unit. The plurality of lasers include at least a red laser and other color lasers,
When selecting the laser that emits the timing detection laser beam, the control unit first detects the intensity fluctuation of the laser light emitted from the red laser, and if the detected intensity fluctuation is within a set range. 8. The method according to claim 1, wherein the red laser is selected as a laser that emits the timing detection laser light without detecting intensity fluctuations of the lasers of the other colors. The image display device according to item. Informing means for informing about the failure of the laser,
When the control unit detects a laser whose intensity fluctuation exceeds a set range among the plurality of lasers, the control unit determines that the laser exceeding the set range is a failure, and notifies the failure of the laser by the notification unit. The image display device according to claim 1, wherein:

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