JP2016118603A - Image display device and image correction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device having a simple configuration, capable of reducing the luminance unevenness of an image caused by the resonance of a mirror and to provide an image correction method.SOLUTION: An image display device 100 of the present invention includes a light source part (RGB laser diode 101), a mirror (a horizontal scanner 210 and a vertical scanner 220) which reflects light emitted from the light source part, a vertical mirror driving part 240 which changes the angle of the mirror on the basis of an applied driving voltage, a vertical mirror angle detection part 270 which detects the angle of the mirror, a vertical mirror control part 300 which applies a driving voltage to the vertical mirror driving part 240, an angle error calculation part 310 which calculates a differential value between a detection angle detected by the vertical mirror angle detection part 270 and the target angle of the mirror, and a light source control part 320 which controls the light quantity of the light source part, so as to cancel the luminance error of a display image caused by the differential value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image display device and an image correction method.

  2. Description of the Related Art An image display device that displays an image by irradiating a screen or the like while scanning laser light with an optical scanner is known.

  Patent Document 1 describes an image display device that can reduce luminance unevenness of an image that occurs due to a decrease in scanning speed in the peripheral portion of a screen when laser light is scanned in the horizontal direction. The image display device of Patent Document 1 controls the laser in synchronization with the variable pixel clock, and changes the laser irradiation position in accordance with the scanning speed of the mirror. As a result, it is possible to reduce the uneven brightness of the image at the periphery of the screen.

  Patent Document 2 describes an image display device that acquires luminance and hue on a screen with an imaging camera and adjusts the output of a laser based on the result. The image display device of Patent Document 2 can reduce unevenness in the brightness of an image by controlling the laser output while feeding back the brightness and hue on the screen.

JP 2014-95787 A JP-A-8-223519

  In an image display device using an optical scanner, generally, as described in Patent Document 1, scanning of a mirror in the vertical direction is performed based on a sawtooth ramp waveform. In the mirror scanning based on the ramp waveform, a sudden angular acceleration is applied to the mirror when returning from the lower end to the upper end of the image, so that resonance based on the natural vibration frequency of the mirror is likely to occur. For this reason, uneven brightness tends to occur near the upper end of the image.

  The image display device described in Patent Document 1 can reduce the luminance unevenness in the horizontal direction, but cannot reduce the luminance unevenness in the vertical direction scanned based on the ramp waveform. In addition, since the detection result of the mirror angle is not used and the laser irradiation position is merely changed based on a predetermined variable pixel clock, the luminance correction of the image corresponding to the mirror angle in real time can be performed. Can not.

  Since the image display device described in Patent Document 2 uses an imaging camera, the configuration of the device is complicated and the cost is high. And since the image projected on the screen is imaged, it cannot be applied to an image display device that does not use a screen such as a head-up display.

  The present invention has been made to solve such problems, and it is an object of the present invention to provide an image display apparatus and an image correction method with a simple configuration capable of reducing uneven brightness of an image due to resonance of a mirror. .

An image display device according to the present invention includes:
A light source unit;
A mirror that reflects the light emitted from the light source unit;
A mirror drive unit for changing the angle of the mirror based on the applied drive voltage;
An angle detector for detecting the angle of the mirror;
A mirror controller for applying the drive voltage to the mirror driver;
An angle error calculation unit that calculates a difference value between a detection angle detected by the angle detection unit and a target angle of the mirror;
A light source control unit that controls a light amount of the light source unit so as to cancel a luminance error of the display image generated based on the difference value.

An image correction method according to the present invention includes:
A light source unit;
A mirror that reflects the light emitted from the light source unit;
A mirror driving unit that changes an angle of the mirror based on an applied driving voltage, and an image correction method in an image display device,
Detecting the angle of the mirror,
Calculating a difference value between the detected angle of the detected mirror and the target angle of the mirror;
The luminance correction of the display image is performed by controlling the light amount of the light source unit so as to cancel the luminance error of the display image generated based on the difference value.

  According to the present invention, it is possible to provide an image display apparatus and an image correction method having a simple configuration that can reduce unevenness in luminance of an image due to mirror resonance.

1 is a block diagram illustrating a configuration of an image display device according to Embodiment 1. FIG. 3 is a perspective view illustrating a configuration of an optical scanner of the image display device according to Embodiment 1. FIG. 3 is a cross-sectional view illustrating a configuration of an optical scanner of the image display device according to Embodiment 1. FIG. FIG. 3 is a perspective view illustrating a configuration of the back surface of the FPC board of the optical scanner in the image display device according to the first embodiment. FIG. 3 is a diagram showing a state in which the reflection surface of the mirror is parallel to the magnetic field in the image display device according to Embodiment 1. In the image display device according to Embodiment 1, it is a diagram showing a state in which the reflection surface of the mirror has an angle with respect to the magnetic field. In the image display device according to Embodiment 1, the magnetic field detection axis of the Hall element is shifted from a state orthogonal to the magnetic field. FIG. 3 is a diagram illustrating a drive waveform and an angle detection waveform in the image display device according to the first embodiment. FIG. 5 is a diagram showing an error differential waveform for controlling the amount of laser light corresponding to mirror resonance in the image display apparatus according to Embodiment 1; 3 is a flowchart illustrating an image correction method in the image display apparatus according to the first embodiment.

[Embodiment 1]
Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram illustrating a configuration of an image display apparatus 100 according to the present embodiment. The image display device 100 is a device that displays an image by projecting a laser beam while scanning the screen or the like, and is, for example, a head-up display or a projector. A vertical direction of a display image displayed by scanning with laser light is also referred to as a V (Vertical) axis direction, and a horizontal direction of the image is also referred to as an H (Horizontal) axis direction.

  The image display apparatus 100 includes an RGB laser diode 101, an optical scanner 200, a vertical mirror angle detection unit 270, a vertical mirror angle detection temperature compensation circuit 280, a controller 102, a reference waveform data generation circuit 103, and a digital-analog. Conversion circuits 104 and 105 (DAC: Digital to Analog Converter), drive amplifier 106, vertical mirror driving unit 240, horizontal mirror driving unit 230, vertical mirror control unit 300, angle error calculation unit 310, and light source control Part 320.

  The RGB laser diode 101 emits laser light of three colors of red (R), green (G), and blue (B) by driving the light source control unit 320. The RGB laser diode 101 is a light source unit that emits a laser beam. The RGB laser diode 101 creates various drawing forms used for the projected display image by controlling the emission intensity and emission time of each color.

  The optical scanner 200 includes a horizontal scanner 210 and a vertical scanner 220. Each of the horizontal scanner 210 and the vertical scanner 220 has a mirror, and scans the light beam by oscillating the mirror at an angle corresponding to the driving voltage and reflecting the light beam. The mirror of the vertical scanner 220 can swing in the vertical direction, and scans the light beam in the vertical direction. The mirror of the horizontal scanner 210 can swing in the horizontal direction and scans the light beam in the horizontal direction.

  The vertical scanner 220 is an optical scanner that reflects the laser light emitted from the RGB laser diode 101 and scans the light flux in the vertical direction by swinging the mirror based on a signal from the vertical mirror control unit 300. The horizontal scanner 210 is an optical scanner that reflects the laser light emitted from the RGB laser diode 101 and scans the light flux in the horizontal direction by swinging a mirror based on a signal from the drive amplifier 106.

  In the image display device 100 according to the present embodiment, the horizontal scanner 210 reflects the laser light from the RGB laser diode 101, and the vertical scanner 220 further reflects the reflected light from the horizontal scanner 210, thereby displaying on the projection surface. An image is being drawn. It can be said that the vertical scanner 220 and the horizontal scanner 210 constitute an optical scanner 200 that reciprocates in the vertical and horizontal directions. For example, the vertical scanner 220 and the horizontal scanner 210 may be a single two-axis (two-dimensional) optical scanner. The vertical scanner 220 and the horizontal scanner 210 can use various methods such as a piezoelectric film method, an electrostatic method, and a coil driving method.

  The horizontal scanning of the mirror in the horizontal scanner 210 is performed by the horizontal mirror driving unit 230 based on a sinusoidal driving voltage. The vertical scanning of the mirror in the vertical scanner 220 is performed by the vertical mirror driving unit 240 based on the driving voltage of the ramp waveform.

  The vertical mirror angle detection unit 270 detects the mirror angle of the vertical scanner 220 and sends the mirror detection angle to the vertical mirror control unit 300 and the angle error calculation unit 310. For example, the vertical mirror angle detection unit 270 may detect a change in the magnetic field strength of the magnet using a Hall element provided on the back surface of the mirror, and calculate the angle of the mirror from the detected magnetic field strength.

  The vertical mirror angle detection temperature compensation circuit 280 is a circuit for correcting the mirror angle value detected by the vertical mirror angle detection unit 270 according to the ambient temperature. In order to perform temperature correction of the magnetic flux density of the magnet and the sensitivity characteristic of the Hall element, a correction vertical mirror angle detection temperature compensation circuit 280 is mounted. Therefore, it is possible to obtain a detection voltage proportional to the mirror angle by correcting the error due to temperature. The vertical mirror angle detection temperature compensation circuit 280 includes a temperature detection element.

  The controller 102 performs processing such as data rearrangement on the input image data and outputs the processed image data to the reference waveform data generation circuit 103. The controller 102 may be realized by hardware such as an FPGA (Field Programmable Gate Array), or may be realized by a program stored in a flash memory and a CPU (Central Processing Unit).

  An image data signal is input from the controller 102 to the reference waveform data generation circuit 103. The reference waveform data generation circuit 103 generates a digital signal having a target reference waveform according to the signal output from the controller 102. The target reference waveform used for driving the vertical scanner 220 is preferably a sawtooth ramp waveform, for example. The reference waveform data generation circuit 103 generates vertical scan waveform data in accordance with the horizontal drawing data read timing, and outputs the waveform data to the digital-analog conversion circuit 105.

  The digital-analog conversion circuits 104 and 105 are electronic circuits that convert digital electric signals into analog electric signals. The digital-analog conversion circuits 104 and 105 convert the target reference waveform generated by the reference waveform data generation circuit 103 into an analog signal. The digital-analog conversion circuit 105 receives a digital signal having a target reference waveform for vertical scanning from the reference waveform data generation circuit 103. The digital-analog conversion circuit 104 receives a digital signal of a target reference waveform for horizontal scanning from the reference waveform data generation circuit 103.

  First, the controller 102 sequentially extracts video data from the memory and generates waveform data of a target reference waveform for horizontal scanning. The generated target reference waveform for horizontal scanning is output to the digital-analog conversion circuit 104. The horizontal scanning waveform data is output to the drive amplifier 106 as a sine waveform by the digital-analog conversion circuit 104.

  The reference waveform data generation circuit 103 generates waveform data of a target reference waveform for vertical scanning in accordance with the data read timing for drawing in the horizontal direction, and outputs the waveform data to the digital-analog conversion circuit 105. The vertical scan waveform data is output as a ramp waveform by the digital-analog conversion circuit 105. The vertical scanner 220 scans in synchronization with the scanning of the horizontal scanner 210 by a servo, thereby drawing a display image.

  The vertical mirror driver 240 and the horizontal mirror driver 230 change the mirror angle based on the applied drive voltage. The vertical mirror driver 240 changes the mirror angle of the vertical scanner 220, and the horizontal mirror driver 230 changes the mirror angle of the horizontal scanner 210. The vertical mirror driving unit 240 and the horizontal mirror driving unit 230 may be configured by a coil provided on the back of the mirror and a magnet provided around the coil. The vertical mirror driving unit 240 and the horizontal mirror driving unit 230 change the direction of the current flowing in the coil and change the direction of the Lorentz force applied to the coil, so that the mirror can be swung.

  The vertical mirror control unit 300 controls the deflection angle, the scanning frequency, and the like so that the mirror of the optical scanner 200 follows the target reference waveform. The vertical mirror controller 300 generates a drive voltage waveform so that the mirror of the optical scanner 200 can obtain a desired deflection angle and frequency. The vertical mirror control unit 300 may be realized by hardware such as an FPGA or an operational amplifier, or may be realized by a program stored in a flash memory and a CPU.

  The vertical mirror controller 300 applies a driving voltage to the vertical mirror driver 240. The vertical mirror control unit 300 includes a mixer 301, an amplifier 302, a phase compensation circuit 303, and a drive amplifier 304. A digital-analog conversion circuit 105, an amplifier 302, a phase compensation circuit 303, a vertical mirror angle detection temperature compensation circuit 280, and a subtractor 311 are connected to the mixer 301. A mixer 301 is connected to the input terminal of the amplifier 302. A drive amplifier 304 and a phase compensation circuit 303 are connected to the output terminal of the amplifier 302.

  Signals output from the digital-analog conversion circuit 105, the vertical mirror angle detection temperature compensation circuit 280, and the phase compensation circuit 303 are input to the mixer 301, added by the mixer 301, and then output to the amplifier 302. The In other words, the mirror drive voltage is adjusted by feeding back the outputs of the vertical mirror angle detection temperature compensation circuit 280 and the phase compensation circuit 303.

  The phase compensation circuit 303 compensates for the phase of the feedback signal in order to stably perform feedback control. In general, when performing negative feedback control, if the output signal is simply fed back to the input signal, the mirror control may become unstable due to the phase characteristics of the amplifier 302 and the sensor. By providing the phase compensation circuit 303, feedback control can be performed stably.

  The drive amplifiers 106 and 304 are amplifiers that amplify current and power. Since the electrical resistances of the coils of the vertical mirror driving unit 240 and the horizontal mirror driving unit 230 are small, an amplifier capable of flowing a large amount of current to the vertical mirror driving unit 240 and the horizontal mirror driving unit 230 is necessary to drive the mirror.

  The angle error calculation unit 310 calculates a difference value between the detection angle detected by the vertical mirror angle detection unit 270 and the target angle of the mirror. The angle error calculation unit 310 includes a subtractor 311. A vertical mirror angle detection temperature compensation circuit 280 and a mixer 301 are connected to the non-inverting input terminal of the subtractor 311. A digital-analog conversion circuit 105 is connected to the inverting input terminal of the subtractor 311. The output (angle detection waveform) of the vertical mirror angle detection temperature compensation circuit 280 is input to the non-inverting input terminal of the subtractor 311, and the input to the inverting input terminal is output from the digital-analog conversion circuit 105. Target reference waveform.

  The light source control unit 320 controls the amount of light of the light source unit (RGB laser diode 101) that renders the display image so as to cancel the luminance error of the display image that occurs based on the difference value between the angle detection waveform and the target reference waveform. The light source control unit 320 includes a differentiation circuit 321, a cancellation amount adjustment circuit 322, and a laser drive circuit 323.

  The difference value signal output from the subtractor 311 is input to the differentiation circuit 321. The differentiating circuit 321 generates a differential value signal (error differential waveform) by differentiating the differential value signal and outputs the differential value signal.

  The differential value signal output from the differentiation circuit 321 is input to the cancellation amount adjustment circuit 322. The cancel amount adjustment circuit 322 calculates a cancel amount to be added to the drive current of the RGB laser diode 101 from the differential value signal, and outputs it to the laser drive circuit 323. For example, the cancellation amount can be calculated by inverting the polarity of the differential value signal.

  The laser drive circuit 323 outputs a drive current to the RGB laser diode 101 in accordance with input image data supplied from the controller 102. The laser drive circuit 323 outputs a drive current obtained by adding the cancel amount calculated by the cancel amount adjustment circuit 322 to the drive current corresponding to the input image data.

  In the light source control unit 320, a difference value signal between the target reference waveform and the angle detection waveform is output from the subtractor 311, and an error differential waveform obtained by differentiating the difference value signal is output from the differentiation circuit 321. The adjustment amount of the laser drive voltage is calculated from the differential waveform. Then, the laser drive circuit 323 adds the adjustment amount to the normal laser drive voltage. The cancel amount adjustment circuit 322 adjusts the cancel amount so that the luminance unevenness is minimized.

  The configuration of the vertical scanner 220 will be described with reference to FIGS. The vertical scanner 220 shown in FIGS. 2 to 4 has a configuration capable of scanning a light beam in one axial direction. FIG. 2 is a perspective view illustrating a configuration of the vertical scanner 220 of the image display apparatus 100. FIG. 2 shows a state in which the vertical scanner 220 is viewed from the front side. FIG. 3 is a cross-sectional view illustrating the configuration of the vertical scanner 220 of the image display apparatus 100. FIG. 4 is a perspective view showing the configuration of the back surface of the vertical scanner 220. The horizontal scanner 210 is generally a resonance type scanner that obtains a driving force by a piezoelectric film, but may have the same configuration as the vertical scanner 220.

  As shown in FIGS. 2 to 4, the vertical scanner 220 includes a case 6, an FPC (Flexible printed circuits) substrate 20, a magnet 4, and a yoke 5. As shown in FIG. 3, the magnet 4 and the yoke 5 are accommodated in the case 6. The magnet 4 generates a magnetic field. The yoke 5 is provided around the magnet 4. The yoke 5 concentrates the magnetic field generated by the magnet 4 around the mirror 31. An FPC board 20 is attached to the front surface of the case 6.

  As shown in FIG. 4, the FPC board 20 includes a frame portion 21, a base 22, a beam 23, a terminal 24, a wiring 25, and a wire spring 26. The frame portion 21, the base 22, and the beam 23 are integrally formed. A base 22 is supported inside the frame portion 21 via a beam 23. The base 22 and the frame part 21 may be reinforced by a backing material such as a polyimide plate. The beam 23 is provided between the base 22 and the frame portion 21. The base 22 is supported by the beam 23 and the wire spring 26 so as to be swingable about the mirror rotation shaft 40.

  As shown in FIGS. 3 and 4, a mirror 31 is provided on the front surface of the base 22, and a driving coil 32 and a hall element 33 are provided on the back surface. The mirror 31 has a reflecting surface that reflects light. The driving coil 32 is provided so as to surround the hall element 33. The mirror 31, the base 22, the driving coil 32, and the Hall element 33 constitute a mirror unit 30. The drive coil 32 and the magnet 4 constitute a vertical mirror drive unit 240.

  The terminal 24, the wiring 25, and the wire spring 26 are formed of a conductive member such as copper, and a circuit that guides an electric signal from the external circuit to the driving coil 32 and a detection signal from the hall element 33 to the external circuit. And a circuit that leads to An external circuit is connected to the terminal 24, and an electric signal input from the terminal 24 is input to the driving coil 32 through the wire spring 26. The detection signal output from the hall element 33 is output to an external circuit via the wiring 25 and the terminal 24. The coil driving current may be supplied through the wire spring 26 or may be supplied through the wiring 25. Since the beam 23 on the FPC board 20 is thin, the number of wires that can be wired to the beam 23 is limited. However, by supplying power to the driving coil 32 through the wire spring 26, the current capacity that can be supplied can be increased.

  When a voltage is applied from the vertical mirror control unit 300 to the driving coil 32, the driving coil 32 receives the Lorentz force from the magnetic field generated by the magnet 4, so the direction of the base 22 is changed according to the driving voltage, The base 22 swings around the mirror rotation axis 40.

  As shown in FIG. 4, the Hall element 33 is provided on the back surface of the base 22 and detects the magnetic field strength of the magnet 4. The image display device 100 detects the angle of the mirror 31 based on the magnetic field intensity detected by the Hall element 33. The hall element 33 and the magnet 4 function as the vertical mirror angle detection unit 270.

  A mechanism in which the Hall element 33 detects the rotation angle of the mirror 31 will be described with reference to FIGS. As shown in FIG. 5, the magnetic field 42 generated by the magnet 4 is concentrated on the mirror unit 30 of the vertical scanner 220 using the yoke 5. The mirror unit 30 swings about the mirror rotation axis 40. The mirror unit 30 includes a mirror 31 and a hall element 33 provided on the opposite surface of the mirror 31. The Hall element 33 can detect a magnetic field in the normal direction of the detection surface. In FIG. 5, the magnetic field detection axis 41 of the Hall element 33 faces rightward in the drawing, and the magnetic field detection axis 41 and the magnetic field 42 are orthogonal to each other, so that the magnetic field detected by the Hall element 33 is zero. .

As shown in FIG. 6, when the mirror unit 30 rotates and the reflection surface of the mirror 31 tilts upward, the angle formed by the magnetic field detection axis 41 of the Hall element 33 and the magnetic field 42 deviates from the state of FIG. 5.
As shown in FIG. 7, when the angle formed by the axis 43 perpendicular to the magnetic field 42 and the magnetic field detection axis 41 is θ (°), the output voltage Vh (V) of the Hall element has a magnetic flux density of B (T) and a Hall When the current is Ih (A) and the coefficient is K (V · A ⁻¹ · T ⁻¹ ), Vh = K · Ih · B · sin θ is calculated.

  As shown in FIG. 8, the vertical scanning of the vertical scanner 220 is performed by applying a driving voltage of a driving waveform W1 (shown by a broken line) to the driving coil. The drive waveform W1 of the vertical scanner 220 is a sawtooth ramp waveform. In FIG. 8, the laser emits light within a vertical drawing range from A to B, and an image is displayed. A corresponds to the upper end of the image, and B corresponds to the lower end of the image. In FIG. 8, the horizontal axis indicates time in milliseconds, and the vertical axis indicates signal intensity in voltage [V].

  The angle detection waveform W2 (indicated by a one-dot chain line) detected by the vertical mirror angle detection unit 270 corresponding to the angle of the mirror 31 vibrates unlike the drive waveform W1 when returning from the lower end of the image to the upper end. I am doing. This is because a large angular acceleration is applied to the mirror 31 when returning from the lower end of the image to the upper end, so that resonance occurs at the natural frequency of the peristaltic part including the mirror 31, and the vibration waveform is added to the ramp waveform. Because.

  Since the mirror 31 resonates in the rotational direction, the rotational angular velocity of the mirror 31 in the drawing area varies. Therefore, when the rotation angular velocity of the mirror 31 is increased, the luminance of the corresponding portion of the display image is decreased, and when the rotation angular velocity is decreased, the luminance of the corresponding portion of the display image is increased. Due to the increase / decrease in the rotation speed due to the resonance of the mirror 31, uneven brightness occurs on the display image.

  FIG. 9 is a diagram showing an error differential waveform W4 for controlling the light amount of the RGB laser diode 101 in accordance with the resonance of the mirror 31. As shown in FIG. In FIG. 9, the horizontal axis indicates time in milliseconds. In the vertical axis, the signal intensity of the waveforms W1 to W3 is indicated by voltage [V] on the left side, and the signal intensity (error differential voltage) of the waveform W4 is indicated by voltage [V] on the right side. In FIG. 9, the target reference waveform W3 is indicated by a thin solid line, and the error differential waveform W4 is indicated by a thick solid line. The target reference waveform W3 is a ramp waveform generated by the reference waveform data generation circuit 103 and converted into a digital signal by the digital-analog conversion circuit 105, and is a waveform corresponding to the target angle of the mirror 31.

  The error differential waveform W4 is calculated by calculating a difference value between the angle detection waveform W2 and the target reference waveform W3 and differentiating the difference value. That is, the error differential waveform W4 is a time series plot of differential values calculated by differentiating the difference value signal. In the image display device 100, the subtractor 311 subtracts the target reference waveform W3 from the angle detection waveform W2, and calculates a difference value between the detection angle of the mirror 31 and the target angle. Then, the differentiating circuit 321 differentiates the difference value to generate an error differential waveform W4. The error differential waveform W4 can be said to be a relative angular velocity signal of the detection angle of the mirror 31 with respect to the target angle of the mirror 31.

  When the difference value between the angle detection waveform W2 and the target reference waveform W3 is constant, the difference between the detection angle of the mirror 31 and the target angle is constant, and the differential value indicating the relative angular velocity is zero. When the difference value between the angle detection waveform W2 and the target reference waveform W3 is small, the detection angle of the mirror 31 is delayed from the target angle, and the mirror 31 moves faster than the target. When the difference value between the angle detection waveform W2 and the target reference waveform W3 becomes large, the mirror 31 moves slower than the target.

  The higher the voltage of the error differential waveform W4, the slower the rotational angular velocity of the mirror 31 and the higher the brightness of the image. The amount of light emitted from the RGB laser diode 101 is controlled by a reverse phase waveform of the error differential waveform W4. Accordingly, the laser drive circuit 323 adjusts the amount of cancellation so that the higher the voltage of the error differential waveform W4, the lower the brightness, so that the uneven brightness of the display image caused by resonance can be canceled.

  The image correction method in the image display apparatus 100 will be described with reference to FIG. First, the vertical mirror angle detector 270 detects the angle of the mirror 31 (ST401). Next, angle error calculation section 310 calculates a difference value between the detected angle of detected mirror 31 and the target angle of mirror 31 (ST402).

  Next, the light source control unit 320 controls the light amount of the light source unit so as to cancel the luminance error of the display image generated based on the difference value (ST403). Specifically, in the image display device 100, the differentiation circuit 321 differentiates the difference value signal to generate a differential value signal. The cancellation amount that the cancellation amount adjustment circuit 322 adds to the drive current of the light source unit is calculated from the differential value signal. The laser drive circuit 323 outputs a drive current obtained by adding the cancel amount calculated by the cancel amount adjustment circuit 322 to the drive current corresponding to the input image data to the light source unit. Thereby, the light source control part 320 controls the light quantity of a light source part.

  The image display apparatus 100 according to the present embodiment feeds back the difference value between the target angle and the detection angle of the mirror 31 to the light source control unit 320 and cancels the luminance error of the display image that occurs based on the difference value. The amount of light of the diode 101 is controlled. Thereby, the luminance unevenness of the display image resulting from the resonance of the mirror 31 can be reduced.

  Furthermore, the image display apparatus 100 according to the present embodiment controls the light amount of the RGB laser diode 101 based on the angle of the mirror 31 detected by the vertical mirror angle detection unit 270. Therefore, it is not necessary to use a complicated configuration such as an imaging camera, and the configuration is simple. In addition, the image display apparatus 100 according to the present embodiment reduces unevenness in luminance of the display image due to resonance of the mirror 31 by controlling the light amount of the RGB laser diode 101. Therefore, it is not necessary to use a damping material or to finely adjust the drive waveform of the mirror 31, so that the configuration is simple.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 5 ... Yoke 6 ... Case 20 ... Board | substrate 21 ... Frame part 22 ... Base 23 ... Beam 24 ... Terminal 25 ... Wiring 26 ... Wire spring 30 ... Mirror part 31 ... Mirror 32 ... Driving coil 33 ... Hall element 40 ... Mirror rotation axis DESCRIPTION OF SYMBOLS 41 ... Magnetic field detection axis 42 ... Magnetic field 43 ... Axis orthogonal to magnetic field 100 ... Image display apparatus 101 ... RGB laser diode 102 ... Controller 103 ... Reference waveform data generation circuit 104, 105 ... Digital-analog conversion circuit 106, 304 ... Drive amplifier DESCRIPTION OF SYMBOLS 200 ... Optical scanner 210 ... Horizontal scanner 220 ... Vertical scanner 230 ... Horizontal mirror drive part 240 ... Vertical mirror drive part 270 ... Vertical mirror angle detection part 280 ... Vertical mirror angle detection temperature compensation circuit 300 ... Vertical mirror control part 301 ... Mixer 302. Amplifier 3 3 ... phase compensating circuit 304 ... drive amplifier 310 ... angular error calculating section 311 ... subtractor 320 ... light source control unit 321 ... differentiating circuit 322 ... cancellation adjustment circuit 323 ... laser drive circuit

Claims (5)

A light source unit;
A mirror that reflects the light emitted from the light source unit;
A mirror drive unit for changing the angle of the mirror based on the applied drive voltage;
An angle detector for detecting the angle of the mirror;
A mirror controller for applying the drive voltage to the mirror driver;
An angle error calculation unit that calculates a difference value between a detection angle detected by the angle detection unit and a target angle of the mirror;
An image display device comprising: a light source control unit that controls a light amount of the light source unit so as to cancel a luminance error of a display image that is generated based on the difference value. The image display device according to claim 1, wherein the light source control unit differentiates the difference value to calculate a differential value, and controls the light amount of the light source unit according to the differential value.   The image display device according to claim 2, wherein the light source control unit increases or decreases the amount of light of the light source unit according to a sign of the differential value. The mirror is swingable in a vertical direction;
The vertical scanning of the mirror is performed based on the driving voltage of the ramp waveform by the mirror driving unit,
The said mirror control part calculates the angle error of the said angle of the said perpendicular direction of the said mirror acquired from the said angle detection part, and the said target angle of the said perpendicular direction. Image display device. A light source unit;
A mirror that reflects the light emitted from the light source unit;
A mirror driving unit that changes an angle of the mirror based on an applied driving voltage, and an image correction method in an image display device,
Detecting the angle of the mirror,
Calculating a difference value between the detected angle of the detected mirror and the target angle of the mirror;
An image correction method for correcting luminance of the display image by controlling a light amount of the light source unit so as to cancel a luminance error of the display image generated based on the difference value.

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