JP2009086371A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device in which lower power consumption is performed by shortening the emission time of light to be detected with a light detection means. <P>SOLUTION: The image display device which displays an image with scanned light has: a light emission means which emits light corresponding to an image signal; an optical scanning means which two-dimensionally scans the light emitted from the light emission means; the light detection means arranged at a position which is outside of an effective scanning region out of the scanning region of the optical scanning means; and a control means which adjusts the timing and the intensity of the light emitted from the light emission means on the basis of the light detected with the light detection means, wherein the control means detects the scanning state of the optical scanning means by emitting the light for inspection from the light emission means in a unit of one or more scanning lines to be detected with the light detection means, thereafter detects the scanning state of the optical scanning means by emitting the light for inspection at a timing when the light for inspection is located at a position within a prescribed range including the light detection means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image display device, and in particular, includes a light emitting unit that emits light according to an image signal, and an optical scanning unit that two-dimensionally scans light emitted from the light emitting unit. The present invention relates to an optical scanning type image display device that displays an image by light scanned by an optical scanning unit.

  Conventionally, the present invention relates to an image display device, and in particular, has a light emitting means for emitting light according to an image signal and an optical scanning means for two-dimensionally scanning light emitted from the light emitting means. 2. Description of the Related Art An optical scanning type image display device that displays an image with light scanned by a scanning unit is known.

The image display device includes a light detection unit that detects light scanned by the light scanning unit. The light scanning unit detects light scanned line by line along the scanning line by the light scanning unit. Based on the detection timing, the scanning state (timing) of the optical scanning unit is detected to control the operation timing of the optical scanning unit (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2003-131151

  However, in the above conventional image display device, the light emitting means emits light in units of one or more lines so that the light scanned by the light scanning means can be detected by the light detecting means. There was a problem.

  Accordingly, an object of the present invention is to provide an image display device capable of reducing power consumption by shortening the light emission time to be detected by the light detection means.

  In view of this, the present invention according to claim 1 includes: a light emitting unit that emits light according to an image signal; and an optical scanning unit that two-dimensionally scans the light emitted from the light emitting unit. In the image display device for displaying an image by the light, the light detecting means arranged at a position outside the effective scanning range of the scanning range by the light scanning means, and the light based on the light detected by the light detecting means. Control means for adjusting the timing and intensity of light emitted from the emission means, and the control means outputs one or more scanning lines for emission of the inspection light to be detected by the light detection means from the light emission means. The scanning state of the optical scanning unit is detected in a unit, and thereafter, the inspection light is emitted at a timing including the light detecting unit and within a predetermined range to detect the scanning state of the optical scanning unit. Detect And wherein the Rukoto.

  According to a second aspect of the present invention, there is provided the image display device according to the first aspect, wherein the image display device is provided at least around the light detection means in a position outside the effective scanning range, and the light to the light detection means is provided. Is characterized by comprising shielding means for shielding light outside the effective scanning range without shielding.

  Moreover, in this invention which concerns on Claim 3, in the image display apparatus of Claim 1, the said optical scanning means has a reflective mirror which reflects the light radiate | emitted from the said light-projection means, The said reflective mirror is used. Resonating type optical scanning means for resonating and scanning light emitted from the light emitting means, and the control means emits the inspection light when the optical scanning means is in a non-resonant state. When the scanning state of the light scanning means is detected in units of scanning lines, and then the light scanning means is in a resonance state, the inspection light is emitted at the timing of the position of the light detecting means. The scanning state of the scanning means is detected.

According to a fourth aspect of the present invention, in the image display device according to the third aspect of the present invention, the image display device further includes a shielding unit that shields the inspection light. The inspection light is sometimes provided in a range where it does not enter, and the blocking means is a maximum range in which the inspection light emission is scanned by the optical scanning means when the optical scanning means is in a non-resonant state. And a position within the predetermined range other than the light detection means.

Moreover, in this invention concerning Claim 5, the image display apparatus of any one of Claims 1-4 scans the light modulated according to the said image signal by the said optical scanning means, A user is made. It is a retinal scanning image display device that projects an image on at least one of the retinas and displays the image.

  According to the present invention, after detecting the scanning state of the light scanning unit, the inspection light is emitted by the light emitting unit at the timing of the position of the light detecting unit, so on the scanning line passing through the light detecting unit, When the light scanning means scans a position other than the position of the light detecting means, the light emitting means does not emit the inspection light, so that the emission time of the inspection light by the light emitting means can be shortened. Power consumption can be reduced.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the following description, an example of a retinal scanning type image display device that projects an image on at least one retina of a user by scanning light modulated according to an image signal by an optical scanning unit and displays the image is taken as an example. However, the present invention is not limited to this. For example, an image is projected on a projection surface such as a screen by scanning a laser beam modulated in accordance with an image signal with an optical scanning unit. The present invention can be applied to other image display devices that display an image by scanning light, such as an optical scanning image display device that performs projection display.

  FIG. 1 is an explanatory diagram showing an image display device in the present embodiment, FIG. 2 is an explanatory diagram showing an operation mode of an optical scanning unit in the present embodiment, and FIG. 3 is a light detecting unit in the present embodiment. FIG. 4 is an explanatory diagram illustrating a control unit of the image display apparatus according to the present embodiment, and FIG. 5 is an explanatory diagram illustrating a scanning mode of inspection light according to the present embodiment. FIG. 6 is an explanatory diagram showing processing performed by the control unit of the image display apparatus according to the present embodiment.

  As shown in FIG. 1, an image display device 1 according to the present embodiment includes a light source unit 2 serving as a light emitting unit that emits light modulated in accordance with an image signal input from the outside, and the light source unit 2 And a control unit 110 as control means for controlling the operation of an optical scanning means having a horizontal scanning system 19 and a vertical scanning system 21 described later.

  The light source unit 2 includes a video signal supply circuit 3 that generates signals serving as elements for synthesizing video based on image signals input from the outside. By operating according to various control signals input from the control unit 110 to be described in detail, the timing and intensity of the emitted light are adjusted.

  The light source unit 2 emits a red laser beam, an R laser beam 13 that emits a green laser beam, and a blue laser beam as a plurality of light sources respectively corresponding to the three primary colors. And a red (R), green (G), and blue (B) video signal 4 (4r, 4g, 4b) transmitted as a video signal 4 from the video signal supply circuit 3. In addition, an R laser driver 10, a G laser driver 9, and a B laser driver 8 are provided for driving the R laser 13, the G laser 12, and the B laser 11, respectively, so as to emit intensity-modulated laser beams. ing.

  Further, the light source unit 2 includes a collimating optical system 14 that collimates the laser light emitted from each laser into parallel light, a dichroic mirror 15 that combines the collimated laser light, and the combined laser light. And a coupling optical system 16 leading to the fiber 17. As the R laser 13, G laser 12, and B laser 11, a semiconductor laser such as a laser diode or a solid-state laser may be used.

  Further, the image display apparatus 1 of the present embodiment includes an optical scanning unit that two-dimensionally scans the laser light emitted from the light source unit 2 that is a light emitting unit. This optical scanning unit is shown in FIG. As described above, the collimating optical system 18 that guides the laser light propagated from the light source unit 2 to the horizontal scanning system 19, and the laser light collimated by the collimating optical system 18 is scanned in the horizontal direction using the galvanometer mirror 19a. A scanning system 19, a first relay optical system 20 that guides laser light scanned by the horizontal scanning system 19 to the vertical scanning system 21, and a laser that is scanned by the horizontal scanning system 19 and incident via the first relay optical system 20 A vertical scanning system 21 that scans light in the vertical direction using a galvano mirror 21a, and a second relay optical that guides laser light scanned by the vertical scanning system 21 to the pupil 24 of the user And a 22.

  The horizontal scanning system 19 in the optical scanning means performs high-speed scanning that scans the laser beam at a high speed relative to the horizontal direction, which is the first scanning direction, for each scanning line of an image to be displayed. The galvanometer mirror 19a that scans the laser beam in the horizontal direction and a horizontal scanning control circuit 19c that controls the driving of the galvanometer mirror 19a are provided.

  As shown in FIG. 2, the galvanometer mirror 19a of the horizontal scanning system 19 has a deflecting surface 19b as a reflecting mirror that reflects the laser light emitted from the light source unit 2, and this deflecting surface 19b is arranged on the rotation axis L. And functions as a resonance type optical scanning unit that scans the laser light emitted from the light source unit 2.

  The horizontal scanning control circuit 19c is a circuit that drives the deflection surface 19b by resonance by applying a driving voltage according to the driving signal input from the control unit 110 to the galvano mirror 19a.

  In the present embodiment, the laser light emitted from the light source unit 2 is projected onto the projection surface when the horizontal scanning control circuit 19c does not apply a driving voltage to the galvano mirror 19a (the galvano mirror 19a is not rotating). The galvanometer mirror 19a is arranged so that the deflecting surface 19b faces in the direction projected at the center position of.

  Further, the galvano mirror 19a as the resonance type optical scanning means has a small rotation angle of the deflecting surface 19b from the time of starting (at the start of applying the drive voltage) to the state of resonance, and the galvano mirror 19a is in the resonance state. After that, the rotation angle of the deflection surface 19b becomes maximum.

  Further, the vertical scanning system 21 in this optical scanning means scans the laser beam in a second direction which is a direction intersecting or orthogonal to the first scanning direction, and one frame of an image to be displayed. 1 functions as a low-speed scanning unit that vertically scans laser light from the first scanning line toward the last scanning line at a low speed relative to the vertical direction, which is the second scanning direction, as shown in FIG. As described above, a galvano mirror 21a that performs vertical scanning and a vertical scanning control circuit 21c that performs drive control of the galvano mirror 21a are provided.

  Further, as described above, the horizontal scanning system 19 is designed to scan the laser beam at a higher speed than the vertical scanning system 21, that is, at a high frequency. Further, as shown in FIG. 1, the horizontal scanning system 19 and the vertical scanning system 21 are connected to the control unit 110 and the video signal supply circuit 3 respectively, and drive signals input from the control unit and the video signal supply circuit 3. The laser beam is scanned based on the horizontal synchronizing signal 5 and the vertical synchronizing signal 6 inputted from the above.

  In the image display device 1 according to the present embodiment, the laser beam is emitted by the horizontal scanning system 19 and the vertical scanning system 21 included in the optical scanning unit, in the first scanning direction and the first scanning direction substantially perpendicular to the first scanning direction. By scanning in two scanning directions, a laser beam corresponding to an image signal is scanned in a two-dimensional direction to form an image in units of frames.

  In addition, as shown in FIGS. 3A and 3B, the image display device 1 of the present embodiment has an image obtained by scanning a laser beam in accordance with an image signal in a scanning range Z of the laser beam by the optical scanning unit. Is provided at a position outside the effective scanning range Za, which is a range in which is displayed or formed, and is a light detection for detecting inspection light described below that is emitted from the light source unit 2 and scanned outside the effective scanning range Za A BD (Beam Detector) sensor 31 is provided as means. In FIG. 1, the BD sensor 31 is configured to be provided above the effective scanning range Za of the laser beam. However, the arrangement position of the BD sensor 31 is not limited to this. It may be configured to be provided below the effective scanning range Za or both above and below.

  Further, the image display device 1 is provided outside the effective scanning range Za of the laser beam and at least around the BD sensor 31, and the laser beam to the BD sensor 31 is not shielded, and the outside of the effective scanning range Za is scanned. Provided with a light shielding mask 31a that functions as a shielding means for shielding the inspection light.

  The light shielding mask 31a shields the inspection light outside the effective scanning range Za, and the light shielding mask 31a is provided in a range where the inspection light is not incident when the optical scanning unit is in a non-resonant state. .

  That is, the light-shielding mask 31a has a maximum range in which the inspection light is scanned by the optical scanning unit when the optical scanning unit is in a non-resonant state, and a position within a predetermined range other than the position where the BD sensor 31 is disposed. Be placed. Note that, as described above, the predetermined range is a scanning range of the inspection light emitted from the light source unit 2 in consideration of an error such as a temperature change.

  When the optical scanning means is in the non-resonant state, the swing angle is extremely small compared to that in the resonant state. If the light scanning means is in a non-resonant state and the light shielding mask 31a is not provided, when the inspection light is emitted from the light emitting means, a part of the retina of the user is irradiated with a considerably high intensity light.

  In view of this, in the image display apparatus 1 according to the present embodiment, when the optical scanning unit is in a non-resonant state, the inspection light is shielded from the maximum range scanned by the optical scanning unit. In addition, the BD sensor 31 is provided at a position close to this range, and there is an advantage that the detection after the optical scanning means enters the resonance state is easy.

  Here, the light shielding mask 31a serving as the shielding means includes a maximum range (first range) in which the inspection light is scanned by the optical scanning means when the optical scanning means is in a non-resonant state, and an arrangement position of the BD sensor 31. It is supposed to be provided as an integral member in a range including a position within a predetermined range (second range) other than the above. The light shielding mask 31a may be formed of different members for the first range and the second range, respectively. At this time, it is preferable to configure the distance between the two as narrow as possible. The low-speed scanning of the inspection light may be performed from the non-resonant state, but it is preferable to start the low-speed scanning after the resonance state in order to prevent leakage of the inspection light.

  Thus, by providing the light-shielding mask 31a, it is possible to prevent the inspection light from entering the eyes of the user and prevent the inspection light from appearing in the display image and making the display image difficult to see. be able to.

  This BD sensor 31 outputs a current corresponding to the intensity of the received inspection light to the control unit 110 as a detection result signal (hereinafter referred to as “BD signal 7”) at the timing when the inspection light is received. It is composed of elements, and is arranged outside the effective scanning range Za by the optical scanning means between the vertical scanning system 21 and the pupil 24 of the user.

  In particular, in the present embodiment, as shown in FIGS. 3A and 3B, the BD sensor 31 is located above the effective scanning range Za and in the center of the horizontal scanning line (Y axis shown in FIG. 3). Since the BD sensor 31 does not detect the inspection light until the galvanometer mirror 19a of the horizontal scanning system 19 is in a resonance state, the galvanometer mirror 19a of the horizontal scanning system 19 When the resonance state is reached, the inspection light is detected.

  Further, as shown in FIG. 4, the control unit 110 of the image display device 1 according to the present embodiment includes a CPU (Central Processing Unit) 102 and stores (stores) various programs executed by the CPU 102. A ROM 107 as a storage device, a RAM 106 functioning as a work area when the CPU 102 executes various programs, and an input / output interface 105 for transmitting / receiving various signals to / from an external circuit are provided. The CPU 102, RAM 106, ROM 107, and input / output interface 105 are electrically connected via a system bus 101.

  The ROM 107 stores an operating system (OS) program for providing basic functions as a computer, a program for receiving an external image signal, a conversion program for converting an external image signal, and a converted image signal. An output program to be output, a program to receive the BD signal 7 from the inside, a program to control the horizontal scanning system 19 and the vertical scanning system 21 based on the BD signal 7, the intensity of the laser light emitted from the light source unit 2 and the laser light A program for adjusting the emission timing is stored by the CPU 102, and functions according to these programs are executed by the CPU 102.

  The input / output interface 105 has a function of transmitting and receiving various signals in the image display apparatus 1. Specifically, the input / output interface 105 receives the BD signal 7 from the BD sensor 31, the horizontal synchronization signal 5 from the video signal supply circuit 3, the vertical synchronization signal 6, various signals from the inside, and the like. There are a control signal indicating an RGB intensity instruction to the signal supply circuit 3, a control signal indicating a laser light emission timing, a control signal indicating an inspection light emission instruction, a system clock, an internal video signal, various control signals, and the like. Is output.

  As described above, the control unit 110 configured as described above reads out and executes the various programs stored in the ROM 107 by the CPU 102, thereby controlling the entire image display apparatus 1 and performing inspection light from the BD sensor 31. Based on the detection timing, the operation timing of the horizontal scanning system 19 and the vertical scanning system 21, the emission timing of the laser beam emitted from the light source unit 2, and the intensity of the laser beam are adjusted. The laser beam emission timing is an important timing used for determining the effective scanning range Za, the display start timing of the image in units of frames, and the like.

  In particular, the control unit 110 according to the present embodiment emits the inspection light to be detected by the BD sensor 31 from the light source unit 2 when the image display apparatus 1 is started up in units of one or more scanning lines. The scanning state by the scanning system 19 and the vertical scanning system 21 is detected.

  That is, when the galvano mirror 19a is in a non-resonant state from when the image display device 1 is activated until the galvano mirror 19a of the horizontal scanning system 19 is in a resonating state, the control unit 110 returns to FIG. As shown, emission from the light source unit 2 is performed in units of scanning lines. FIG. 5A shows the moment when the galvanometer mirror 19a of the horizontal scanning system 19 is in a resonance state.

  In the present embodiment, as described above, the BD sensor 31 is provided at a position where the inspection light is not detected until the galvanometer mirror 19a of the horizontal scanning system 19 is in a resonance state. When the rotation angle of the galvanometer mirror 19a of the system 19 is small and the BD sensor 31 does not detect the inspection light, it can be detected that the galvanometer mirror 19a of the horizontal scanning system 19 is in a non-resonant state.

  On the other hand, as shown in FIG. 5A, the control unit 110 causes the light source unit 2 to emit light in units of scanning lines, and the inspection light scanned outside the effective scanning range Za causes the BD sensor to emit light. Since the BD sensor 31 detects the inspection light when crossing, it is possible to detect that the galvano mirror 19a of the horizontal scanning system 19 is in the resonance state by the detection timing of the inspection light by the BD sensor 31. it can.

  At this time, the control unit 110 determines the position of the galvano mirror 19a at the time when the BD sensor 31 detects the inspection light from the arrangement position of the BD sensor 31 and the timing (detection time) when the BD sensor 31 detects the inspection light. It is possible to accurately detect which direction the deflection surface 19b is directed, that is, which position on the projection surface the optical scanning unit is scanning.

  Since the galvanometer mirror 19a of the horizontal scanning system 19 performs a reciprocating rotation operation at a predetermined resonance frequency after being in a resonance state, the controller 110 first starts the BD sensor 31 after the image display device 1 is activated. Using the time when the inspection light is detected as a reference, it is possible to calculate the timing at which laser light corresponding to the image signal is emitted from the light source unit 2 when displaying an image of one frame thereafter.

  In addition, as described above, the control unit 110 accurately detects the orientation of the deflection surface 19b of the galvanometer mirror 19a at the time when the BD sensor 31 first detects the inspection light after the image display device 1 is activated. After that, while the galvanometer mirror 19a of the horizontal scanning system 19 is operating in the resonance state, the optical scanning means is set to BD every predetermined time from the time when the BD sensor 31 first detects the inspection light. It can be predicted that the position of the sensor will be scanned.

  Therefore, after the image display apparatus 1 is activated, the control unit 110 according to the present embodiment first detects the inspection light, that is, after the galvano mirror 19a of the horizontal scanning system 19 enters the resonance state. The light source unit 2 can emit the inspection light at the timing when the scanning position by the horizontal scanning system 19 and the vertical scanning system 21 becomes the arrangement position of the BD sensor 31. The emission of the inspection light at this time is a predetermined range including the BD sensor 31 so that the BD sensor 31 receives the inspection light even when there is an error such as a change in the scanning position of the optical scanning unit due to a temperature change. To do.

  That is, after the galvanometer mirror 19a of the horizontal scanning system 19 is in a resonance state, the control unit 110 determines that the scanning position by the optical scanning means is the position where the BD sensor 31 is disposed, as shown in FIG. The inspection light can be emitted from the light source unit 2 only during a certain period. In FIG. 5B, outside the effective scanning range Za, a period in which the light source unit 2 does not emit inspection light is indicated by a dotted line, and a period in which inspection light is emitted is indicated by a solid line. .

  As described above, in the image display device 1 of the present embodiment, only after the galvano mirror 19a of the horizontal scanning system 19 is in the resonance state, the scanning position by the optical scanning unit is only during the period when the BD sensor 31 is disposed. Since the control unit 110 causes the light source unit 2 to emit the inspection light, the inspection light emission time can be shortened compared to the case where the inspection light is always emitted in units of lines. The power consumption of the device 1 can be reduced.

  Then, the control unit 110 displays an image for each frame from the timing at which the BD sensor 31 detects the inspection light at a predetermined cycle after the galvanometer mirror 19a of the horizontal scanning system 19 enters the resonance state. The timing for emitting the laser beam corresponding to the image signal from the light source unit 2 is adjusted.

  Thus, since the control unit 110 adjusts the emission timing of the laser beam for displaying the image, the image display device 1 can accurately scan the laser beam for image display within the effective scanning range Za. It is possible to suitably prevent the frame from being shifted during image display.

  In addition, the control unit 110 of the image display device 1 performs feedback control so that the current value of the BD signal 7 input from the BD sensor 31 becomes a constant value.

  Therefore, even when the intensity of the laser light emitted from the light source unit 2 changes due to heat generated from the light source unit 2, the intensity of the laser light can be returned to a predetermined reference value. Therefore, the luminance of the display image can be prevented from changing irregularly.

  Next, processing performed by the control unit 110 of the image display apparatus 1 configured as described above will be described with reference to FIG.

  Here, based on the detection result of the BD sensor 31, which is the main part of the present invention, the scanning state of the optical scanning means is detected, and control is performed to emit inspection light from the light source unit 2 according to the detection result. Only the inspection light emission control process executed by the unit 110 will be described.

  This inspection light emission control process is a process that is started when the image display apparatus 1 is turned on and is repeatedly executed until the power is turned off.

  When the image display apparatus 1 is powered on, the control unit 110 first activates the optical scanning unit (step S01) and then moves the process to step S02 as shown in FIG.

  Here, the control unit 110 outputs drive signals to the horizontal scanning control circuit 19c and the vertical scanning control circuit 21c, and the reciprocating rotation operation of the galvano mirror 19a of the horizontal scanning system 19 and the galvano mirror 21a of the vertical scanning system 21. To start.

  Next, in step S02, the control unit 110 outputs a control signal to the light source unit unit 2 to continuously emit inspection light, and then the process proceeds to step S03.

  Here, as shown in FIG. 5A, the control unit 110 performs a process of continuously scanning the inspection light in units of lines in the scanning range Z above the effective scanning range Za. At this time, immediately after starting the optical scanning means, the galvano mirror 19a of the horizontal scanning system 19 is in a non-resonant state, so that the inspection light scans in the vicinity of the approximate center of the scanning range Z above the effective scanning range Za. Thereafter, when the galvanometer mirror 19a of the horizontal scanning system 19 is in a resonance state, the inspection light is scanned so as to cross the scanning range Z above the effective scanning range Za to the left and right.

  Next, in step S03, the control unit 110 determines whether or not the BD signal 7 indicating that the inspection light is detected is received from the BD sensor 31, and when it is determined that the BD signal 7 is received. (Step S03: Yes), the process proceeds to step S04, and when it is determined that the BD signal 7 has not been received (step S03: No), the process proceeds to step S02.

  At this time, when the BD signal 7 is received, the control unit 110 determines that the galvano mirror 19a of the horizontal scanning system 19 is in a resonance state, and when the BD signal 7 is not received, It is determined that the galvanometer mirror 19a is still in a non-resonant state.

  In step S03, when the control unit 110 receives the BD signal 7, it is determined that the galvanometer mirror 19a of the horizontal scanning system 19 is in a resonance state, and the process proceeds to step S04. Instead of step S03, when the control unit 110 receives the BD signal 7 at a predetermined resonance period, it is determined that the galvano mirror 19a is in a resonance state, and the process proceeds to step S04. While the BD signal 7 is not received at this resonance period, it may be determined that the galvanometer mirror 19a is in a non-resonant state, and the process may proceed to step S02.

  This not only prevents the control unit 110 from misidentifying that the galvano mirror 19a is in the resonance state by chance that the BD sensor 31 detects the inspection light when the galvano mirror 19a is in the non-resonance state. Even when the BD sensor 31 is disposed at the center of the scanning line, the control unit 110 can reliably detect that the galvano mirror 19a is in a resonance state, and therefore the area of the light shielding mask 31a can be increased. Therefore, the optical scanning unit can be downsized.

  Next, in step S04, the control unit 110 outputs a control signal to the light source unit unit 2, causes the light source unit unit 2 to intermittently emit an inspection signal, and then proceeds to step S05.

  Here, from the reception timing of the BD signal 7 received in step S03, that is, the time when the BD sensor 31 detects the inspection signal, the control unit 110 next determines the position where the BD sensor 31 is disposed. The time until scanning is calculated based on the system clock, and the inspection light is intermittently emitted at the calculated time interval so that the scanning position by the optical scanning means comes to the position where the BD sensor 31 is disposed. Only the light source unit 2 is caused to emit inspection light.

  Next, in step S05, the control unit 101 determines whether or not the BD signal 7 indicating that the inspection light is detected is received from the BD sensor 31, and when it is determined that the BD signal 7 is received. (Step S05: Yes), the process proceeds to step S06, and when it is determined that the BD signal 7 has not been received (step S05: No), the process proceeds to step S02.

  Here, when the control unit 101 receives the BD signal 7, the control unit 101 determines that the galvano mirror 19 a of the horizontal scanning system 19 maintains the resonance state, and when it does not receive the BD signal 7, the horizontal scanning is performed. It is determined that the galvanometer mirror 19a of the system 19 is in a non-resonant state.

  Next, in step S06, the control unit 110 determines whether an image signal is input from the outside to the video signal supply circuit 3, and when determining that the image signal is input (step S06: Yes), The process proceeds to step S07, and when it is determined that no image signal is input (step S06: No), the process proceeds to step S08.

  Here, when the control unit 110 detects that the horizontal synchronization signal 5 and the vertical synchronization signal 6 are output from the video signal supply circuit 3, the control unit 110 determines that an image signal is input to the video signal supply circuit 3, If it is not detected that the horizontal synchronizing signal 5 and the vertical synchronizing signal 6 are output from the video signal supply circuit 3, it is determined that no image signal is input to the video signal supply circuit 3.

  Next, in step S07, the control unit 110 performs a process of displaying an image, and then moves the process to step S04.

  Here, the control unit 110 outputs a control signal for emitting a laser beam corresponding to the image signal to the light source unit unit 2 to display images sequentially in units of frames.

  Further, in step S08, the control unit 101 determines whether or not a predetermined time has elapsed since the image signal is no longer input. If it is determined that the predetermined time has not elapsed (step S08: No), the control unit 101 performs processing. The process proceeds to step S04, and when it is determined that the time has elapsed (step S08: Yes), the inspection light emission control process is terminated.

  As described above, in the image display apparatus 1 according to the present embodiment, the control unit 110 is above the effective scanning range Za until the galvano mirror 19a of the horizontal scanning system 19 included in the optical scanning unit changes from the non-resonant state to the resonant state. In the scanning range Z, the inspection light is emitted from the light source unit 2 so that the inspection light is scanned line by line, and the inspection light is detected by the BD sensor 31, so that the scanning position of the optical scanning means After the galvanometer mirror 19a of the horizontal scanning system 19 is in a resonance state, the light source unit 2 is used for inspection only when the scanning position of the optical scanning means comes to the position where the BD sensor 31 is disposed. Since the control for emitting the light is performed, the emission time of the inspection light can be shortened, whereby the power consumption of the image display device 1 can be reduced.

  Further, in the inspection light emission control process shown in FIG. 6, the inspection light is continuously emitted (step S02) immediately after the optical scanning unit is activated (step S01). The time from when the galvanometer mirror 19a of the scanning system 19 is activated until the resonance state is obtained is measured, and the measurement result is stored in the RAM 106 of the control unit 110, and stored in the RAM 106 after the process of step S01. The process of step 02 may be performed after the time until the resonance state is reached.

  By performing the inspection light emission control process in this way, the number of times that the inspection light is continuously emitted before the BD sensor 31 detects the inspection light can be reduced, so that the power consumption of the image display device 1 can be reduced. This can be further reduced.

It is explanatory drawing which shows the image display apparatus in this embodiment. It is explanatory drawing which shows the operation | movement aspect of the optical scanning means in this embodiment. It is explanatory drawing which shows the arrangement | positioning position of the photon detection means in this embodiment. It is explanatory drawing which shows the control part of the image display apparatus in this embodiment. It is explanatory drawing which shows the scanning aspect of the inspection light in this embodiment. It is explanatory drawing which shows the process which the control part of the image display apparatus in this embodiment performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical scanning device 2 Light source unit part 19 Horizontal scanning system 19a Galvano mirror 21 Vertical scanning system 21a Galvano mirror 31 BD sensor 31a Shading mask 110 Control part

Claims (5)

In an image display device, comprising: a light emitting unit that emits light according to an image signal; and an optical scanning unit that two-dimensionally scans the light emitted from the light emitting unit, and displays an image by the scanned light ,
A light detecting means arranged at a position outside the effective scanning range of the scanning range by the light scanning means;
Control means for adjusting the timing and intensity of the light emitted from the light emitting means based on the light detected by the light detecting means;
The control means detects the scanning state of the light scanning means by performing emission from the light emitting means of the inspection light to be detected by the light detection means in units of one or more scanning lines, and thereafter An image display apparatus characterized in that the inspection light is emitted at a timing including a position within a predetermined range including the light detection means to detect a scanning state of the light scanning means.   Among the positions outside the effective scanning range, there is provided shielding means that is provided at least around the light detection means and shields light outside the effective scanning range without shielding light to the light detection means. The image display device according to claim 1. The optical scanning unit includes a reflection mirror that reflects light emitted from the light emission unit, and is a resonance type optical scanning unit that resonates the reflection mirror and scans the light emitted from the light emission unit. Yes,
The control means detects the scanning state of the recording scanning means by emitting the inspection light in units of one or more scanning lines when the optical scanning means is in a non-resonant state, and then the optical scanning means 2. The image display device according to claim 1, wherein when in a resonance state, the inspection light is emitted at a timing corresponding to a position of the light detection unit to detect a scanning state of the optical scanning unit. A shielding means for shielding the inspection light;
The light detection means is provided in a range in which the emission of the inspection light is not incident when the light scanning means is in a non-resonant state,
The blocking means includes a maximum range in which emission of the inspection light is scanned by the optical scanning means when the optical scanning means is in a non-resonant state, and a position within the predetermined range other than the light detection means. The image display device according to claim 3, wherein the image display device is disposed on the screen.   The image display device according to any one of claims 1 to 4, wherein an image is projected onto at least one retina of a user by scanning the light modulated according to the image signal with the optical scanning unit, An image display device which is a retinal scanning image display device for displaying an image.

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