JP2007047355A - Optical scanner and image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner or the like in which the generation of crosstalk between adjacent pixels is reduced and a high resolution image is displayed. <P>SOLUTION: The optical scanner scans a light beam corresponding to an image signal and has: a light source part which supplies the light beam; a scanning part which scans the light beam from the light source part in a first direction and a second direction which is substantially orthogonal to the first direction in a region to be irradiated with the light beam. The scanning part is driven so that the frequency at which the light beam is scanned in the first direction may be higher than the frequency at which the light beam is scanned in the second direction. The light source part is driven so that the lighting time ton of the light beam for forming one pixel may be not longer than the time in which the light beam is scanned in the distance which is given by subtracting the length dx of the spot SP in the first direction formed by the light beam in the region to be irradiated from the length Px of the pixel in the first direction formed according to the image signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical scanning device and an image display device, and more particularly to a technology of an optical scanning device for displaying an image by scanning a laser beam modulated in accordance with an image signal.

  An optical scanning device that scans a laser beam is used as an image display device that displays an image by scanning the laser beam. The optical scanning device scans a laser beam modulated in accordance with an image signal in a two-dimensional direction. The image display device displays an image by causing laser light from the optical scanning device to enter a screen or the like. As a technique of an image display device that displays an image by scanning a laser beam, for example, there is one proposed in Patent Document 1.

JP 11-295630 A

  The laser beam forms a spot in an irradiated area such as a screen. When laser beam modulation is performed using the timing at which the center position of the spot enters the pixel area, the laser beam spot for displaying one pixel may enter the pixel area adjacent to the pixel. is there. For this reason, according to the conventional technique, there is a problem in that so-called crosstalk may occur, in which an image is blurred when modulated light is incident on a position different from the address information of the image signal. When crosstalk occurs, it becomes difficult to display a high-resolution image because the outline of the image becomes unclear. The present invention has been made in view of the above problems, and provides an optical scanning device and an image display device that can reduce the occurrence of crosstalk between adjacent pixels and display a high-resolution image. With the goal.

  In order to solve the above-described problems and achieve the object, according to the present invention, there is provided an optical scanning device that scans a beam of light according to an image signal. A scanning unit that scans the beam light in a first direction and a second direction substantially orthogonal to the first direction in the irradiated region, and the scanning unit scans the beam light in the first direction. The frequency is driven so as to be higher than the frequency for scanning the light beam in the second direction, and the light source unit has a lighting time of the light beam for forming one pixel formed according to the image signal. It is driven so as to be less than the time for scanning the beam light at a distance obtained by subtracting the length in the first direction of the spot formed in the irradiated region by the beam light from the length of the pixel in the first direction. An optical scanning device is provided. Door can be.

  As the length of the spot in the first direction, for example, the length between positions where the beam light attenuates to about half the intensity of the peak intensity of the beam light can be set. The maximum lighting time of the light beam for forming one pixel is determined from the length of the pixel and the length of the spot in the first direction. By determining the maximum lighting time for each pixel in this way, it is possible to prevent the beam light for displaying one pixel from entering the area of the pixel adjacent to the pixel. By keeping the laser light in the area of each pixel, it is possible to reduce the occurrence of crosstalk between adjacent pixels in the first direction. As a result, the occurrence of crosstalk between adjacent pixels can be reduced, and an optical scanning device for displaying a high-resolution image can be obtained.

  Further, according to a preferred aspect of the present invention, the light source unit is driven so as to express the gradation according to the image signal, and the light beam lit so as to express the gradation of one pixel is the minimum level. It is desirable to drive so as to pass through the boundary between pixels at a timing of attenuation to an intensity higher than the intensity for expressing the key. The occurrence of crosstalk between pixels can be reduced by setting the lighting time of the beam light for each pixel to be equal to or shorter than the above maximum lighting time. On the other hand, if the lighting time of the beam light for each pixel is made too short, a portion where the intensity of the beam light is extremely lowered is generated at each boundary between pixels. When a dark portion generated at each pixel boundary is recognized by an observer, it is difficult to display a high-quality image. Therefore, by determining the minimum lighting time of the beam light for each pixel according to this aspect, it becomes possible to make the boundary between the pixels inconspicuous. Thereby, an optical scanning device for displaying a seamless and high-quality image can be obtained.

  According to a preferred aspect of the present invention, it is desirable that the light source unit is driven in accordance with a drive signal whose amplitude is controlled in accordance with an image signal. As a result, the beam light can be modulated using amplitude modulation.

  As a preferred aspect of the present invention, it is desirable that the light source unit is driven according to a drive signal whose pulse width is controlled according to an image signal. Thereby, the beam light can be modulated by using pulse width modulation (hereinafter referred to as “PWM”).

  As a preferred aspect of the present invention, the light source unit is preferably driven according to a pulse signal having a pulse width set around the timing at which the beam light scans the center position of the pixel in the first direction. . In PWM, the pulse width for turning on the light beam is changed according to the image signal. By setting the pulse width around the timing at which the light beam scans the center position of the pixel, even when the light beam is reciprocated in the first direction, the incident timing of the light beam to each pixel can be made uniform. It becomes possible. By aligning the incident timing of the beam light with respect to each pixel, it is possible to reduce the displacement of the pixel position in the first direction. Thereby, an optical scanning device for displaying a higher quality image with little deviation can be obtained.

  Moreover, as a preferable aspect of the present invention, it is desirable that the light source unit forms a spot having a shape longer in the second direction than in the first direction in the irradiated region. By forming a short spot in the first direction, it is possible to reduce the occurrence of crosstalk and increase the lighting time of the beam light for one pixel. Further, by forming a long-shaped spot in the second direction, it is possible to reduce the gap between pixels in the second direction. As a result, an optical scanning device for displaying a bright image that is seamless and has little crosstalk can be obtained.

  Furthermore, according to the present invention, there is provided an image display device for displaying an image by light from an optical scanning device, wherein the optical scanning device is the optical scanning device described above. Can do. By providing the above optical scanning device, occurrence of crosstalk between adjacent pixels can be reduced, and a high-resolution image can be displayed. Thereby, the occurrence of crosstalk between adjacent pixels can be reduced, and an image display device capable of displaying a high-resolution image can be obtained.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 shows a schematic configuration of an image display apparatus 100 according to Embodiment 1 of the present invention. The image display device 100 is a so-called rear projector that supplies laser light to one surface of the screen 110 and observes an image by observing light emitted from the other surface of the screen 110. An optical scanning device 120 provided in the image display device 100 scans a laser beam corresponding to an image signal. The optical scanning device 120 includes a laser device 101, an illumination optical system 102, and a scanning unit 200. The image display device 100 displays an image with a laser beam from the optical scanning device 120.

  FIG. 2 shows a schematic configuration of the laser apparatus 101. The laser device 101 includes an R light source 121 </ b> R that supplies red laser light (hereinafter referred to as “R light”) that is beam light, and green laser light (hereinafter referred to as “G light”) that is a beam light. Light source unit 121G for supplying G light and B light source unit 121B for supplying blue laser light (hereinafter referred to as “B light”) which is beam light.

  Each color light source unit 121R, 121G, 121B supplies laser light modulated in accordance with an image signal. The laser device 101 is provided with two dichroic mirrors 124 and 125. The dichroic mirror 124 transmits R light and reflects G light. The dichroic mirror 125 transmits R light and G light and reflects B light. The R light from the R light source unit 121 </ b> R passes through the dichroic mirrors 124 and 125 and is then emitted from the laser device 101.

  The G light from the G light source 121G is reflected by the dichroic mirror 124, whereby the optical path is bent by approximately 90 degrees. The G light reflected by the dichroic mirror 124 passes through the dichroic mirror 125 and is then emitted from the laser device 101. The B light from the B light source 121B is reflected by the dichroic mirror 125, so that the optical path is bent by approximately 90 degrees. The B light reflected by the dichroic mirror 125 is emitted from the laser device 101. In this way, the laser device 101 supplies R light, G light, and B light modulated according to the image signal.

  Returning to FIG. 1, the laser light from the laser device 101 enters the scanning unit 200 after passing through the illumination optical system 102. The light from the scanning unit 200 enters the reflection unit 105 after passing through the projection optical system 103. The illumination optical system 102 and the projection optical system 103 image the laser light from the laser device 101 on the screen 110. The reflection unit 105 reflects the laser light from the scanning unit 200 toward the screen 110. The housing 107 seals the space inside the housing 107.

  The screen 110 is provided on a predetermined surface of the housing 107. The screen 110 is a transmissive screen that transmits laser light modulated in accordance with an image signal. The light from the reflection unit 105 enters from the surface of the screen 110 on the inner side of the housing 107 and then exits from the surface on the viewer side. The observer observes the image by observing the light emitted from the screen 110.

  FIG. 3 shows a schematic configuration of the scanning unit 200. The scanning unit 200 has a so-called double gimbal structure having a reflection mirror 202 and an outer frame portion 204 provided around the reflection mirror 202. The outer frame portion 204 is connected to a fixed portion (not shown) by a torsion spring 206 that is a rotating shaft. The outer frame portion 204 rotates around the torsion spring 206 using the twist of the torsion spring 206 and the restoration to the original state. The reflection mirror 202 is connected to the outer frame portion 204 by a torsion spring 207 that is a rotation axis substantially orthogonal to the torsion spring 206. The reflection mirror 202 reflects the laser light from the laser device 101. The reflection mirror 202 can be configured by forming a highly reflective member, for example, a metal thin film such as aluminum or silver.

  The reflection mirror 202 is displaced so that the laser beam is scanned in the Y direction (see FIG. 1) on the screen 110 when the outer frame portion 204 rotates about the torsion spring 206. The reflection mirror 202 rotates about the torsion spring 207 using the twist of the torsion spring 207 and the restoration to the original state. The reflection mirror 202 is displaced so as to scan the laser beam reflected by the reflection mirror 202 in the X direction by rotating about the torsion spring 207. Thus, the scanning unit 200 repeatedly scans the laser light from the laser device 101 in the X direction and the Y direction.

  FIG. 4 illustrates a configuration for driving the scanning unit 200. Assuming that the side on which the reflection mirror 202 reflects the laser light is the front side, the first electrodes 301 and 302 are spaces on the back side of the outer frame portion 204 and are provided at substantially symmetrical positions with respect to the torsion spring 206. Yes. When a voltage is applied to the first electrodes 301 and 302, a predetermined force corresponding to the potential difference, for example, an electrostatic force, is generated between the first electrodes 301 and 302 and the outer frame portion 204. The outer frame portion 204 rotates about the torsion spring 206 by alternately applying a voltage to the first electrodes 301 and 302.

  Specifically, the torsion spring 207 includes a first torsion spring 307 and a second torsion spring 308. A mirror-side electrode 305 is provided between the first torsion spring 307 and the second torsion spring 308. A second electrode 306 is provided in the space behind the mirror side electrode 305. When a voltage is applied to the second electrode 306, a predetermined force according to the potential difference, for example, an electrostatic force, is generated between the second electrode 306 and the mirror side electrode 305. When a voltage having the same phase is applied to any of the second electrodes 306, the reflection mirror 202 rotates about the torsion spring 207. The scanning unit 200 rotates the reflection mirror 202 in this way, thereby scanning the laser light in the two-dimensional direction. The scanning unit 200 can be created by, for example, MEMS (Micro Electro Mechanical Systems) technology.

  For example, during one frame period of the image, the scanning unit 200 causes the reflection mirror 202 to reciprocate the laser light a plurality of times in the horizontal X direction while scanning the laser light once in the vertical Y direction. Displace. Assuming that the X direction is the first direction and the Y direction is the second direction substantially orthogonal to the first direction, the scanning unit 200 has a frequency at which the laser beam is scanned in the first direction. Driven to be higher than the frequency of scanning light. In order to scan the laser beam in the X direction at high speed, it is desirable that the scanning unit 200 be configured to resonate the reflection mirror 202 around the torsion spring 207. By resonating the reflection mirror 202, the amount of displacement of the reflection mirror 202 can be increased. By increasing the displacement amount of the reflection mirror 202, the scanning unit 200 can efficiently scan the laser beam with less energy. Note that the reflection mirror 202 may be driven without using resonance.

  The scanning unit 200 is not limited to a configuration that is driven by an electrostatic force corresponding to a potential difference. For example, the structure driven using the expansion-contraction force or electromagnetic force of a piezoelectric element may be sufficient. The scanning unit 200 may include a reflection mirror that scans the laser light in the X direction and a reflection mirror that scans the laser light in the Y direction. Furthermore, the scanning unit 200 is not limited to a configuration using a galvanometer mirror, and may use a polygon mirror that rotates a rotating body having a plurality of mirror pieces.

  FIG. 5 explains the shape of the spot SP of the laser beam in the irradiated region on the screen 110 and the lighting time of the laser beam for forming one pixel. Here, the description will be made focusing on one color light of R, G, and B. FIG. 5 shows a state in which the laser beam for forming the spot SP scans the area of the pixel P in the right direction that is the plus X direction.

  For example, it is assumed that the intensity distribution of the laser light in the spot SP substantially matches a Gaussian distribution having a peak at the center position of the spot SP in the X direction and the Y direction. The outer edge of the spot SP can be a line that attenuates to approximately half the intensity of the peak intensity of the laser beam at the spot SP. The spot SP has an elliptical shape in which the length dx in the X direction, which is the first direction, is the short axis, and the length dy in the Y direction, which is the second direction, is the long axis. Each color light source unit forms a spot SP having a shape longer in the second direction than in the first direction in the irradiated region. For shaping the spot SP, for example, a refraction action by a lens or a prism can be used.

  In the spot SP at the timing T1 at which the laser beam is turned on to display the pixel P, the left boundary line bl of the pixel P and the left end of the spot SP substantially coincide. Thereafter, the right boundary line br of the pixel P and the right end of the spot SP substantially coincide with the spot SP at the timing T2 at which the laser beam is turned off. The interval ΔS between the spot SP at the timing T1 and the spot SP at the timing T2 substantially matches the distance obtained by subtracting the length dx of the spot SP in the X direction from the length Px of the pixel P in the X direction.

  A time ton between the timing T1 and the timing T2 is a lighting time of the laser light for forming the pixel P. The lighting time ton is shorter than the time tp for scanning the pixel P with the laser beam. Each color light source unit is driven so that the lighting time ton substantially coincides with the scanning time of the laser light at a distance obtained by subtracting the length dx of the spot SP from the length Px of the pixel P.

  FIG. 6 explains the light source drive pulse signal and the intensity of the laser beam in each pixel. Here, description will be made assuming that the laser light is modulated so that the maximum gradation is expressed in each pixel. The light source drive pulse signal is used to turn on the laser light at the lighting time ton described with reference to FIG. At timing T1, the laser light takes an intensity distribution L1 that peaks at timing T1. Similarly, at the timing T2, the laser light has an intensity distribution L2 that peaks at the timing T2. The observer recognizes the laser beam having an intensity obtained by integrating the intensity of the laser beam scanned during the lighting time ton.

  FIG. 7 explains the intensity of the laser light on the boundary between the pixels P. FIG. It is assumed that the laser light is turned off at the timing T2 for one pixel P, and the lighting of the laser light is started for the next pixel P at the timing T1 '. At timing T2, the intensity of the laser beam that is turned on to display the next pixel is added to the peak intensity Imax of the intensity distribution L2. At a timing Tb that passes over the boundary between the pixels P, the intensity Imax / 2 of the intensity distribution L2 and the intensity Imax / 2 of the intensity distribution L1 'are integrated to obtain a peak intensity Imax. At timing T <b> 1 ′, the intensity of the laser light that has been lit for the previous pixel is added to the peak intensity Imax of the intensity distribution L <b> 1 ′. Therefore, the laser beam is supplied to the irradiated region with an envelope intensity distribution L0 that attenuates at each timing Tb.

  For example, assuming that the time tp for passing over the pixel P is all the laser light lighting time, the intensity distribution L0 is substantially linear. In addition to a substantially linear intensity distribution, if a laser beam spot for displaying one pixel P enters an area of an adjacent pixel, crosstalk is likely to occur. On the other hand, according to the present embodiment, it is possible to prevent laser light having an intensity of Imax / 2 or more for forming one pixel P from entering the region of the pixel P adjacent to the pixel P. By keeping laser light having an intensity of Imax / 2 or more in the area of each pixel, occurrence of crosstalk between the pixels P can be reduced. As a result, the occurrence of crosstalk between adjacent pixels can be reduced, and an effect that a high-resolution image can be displayed is achieved.

  Further, by forming a spot SP having a shape that is longer in the Y direction, which is the second direction, than the X direction, which is the first direction, in the irradiated region, the occurrence of crosstalk is reduced, and a laser for one pixel is formed. It becomes possible to increase the lighting time ton. Further, by forming a spot SP having a long shape in the Y direction, it is possible to reduce a gap between pixels in the Y direction. This makes it possible to display a bright image that is seamless and has little crosstalk.

  FIG. 8 shows a block configuration for controlling the image display apparatus 100. The image signal input unit 711 performs characteristic correction and amplification of the image signal input from the input terminal. For example, the image signal input unit 711 outputs an intensity signal for light source modulation in an analog format by amplifying the analog image signal. In addition, the image signal input unit 711 may be configured to convert a digital image signal into an analog signal. The synchronization / image separation unit 712 separates the signal from the image signal input unit 711 into an image information signal, a vertical synchronization signal, and a horizontal synchronization signal for each of R light, G light, and B light, and outputs them to the control unit 713. To do. The image processing unit 721 in the control unit 713 divides the image information into information for each frame and outputs the information to the frame memory 714. The frame memory 714 stores the image signal from the image processing unit 721 in units of frames.

  The scanning control unit 723 of the control unit 713 generates a drive signal for driving the scanning unit 200 based on the vertical synchronization signal and the horizontal synchronization signal. The scan driver 715 drives the scanner 200 in response to a drive signal from the controller 713. The horizontal angle sensor 716 detects the swing angle of the reflection mirror 202 (see FIG. 3) that scans the laser beam in the X direction on the screen 110. The vertical angle sensor 717 detects the swing angle of the reflection mirror 202 that causes the screen 110 to scan the laser beam in the Y direction. The signal processing unit 718 generates a frame start signal F_Sync from the displacement of the vertical angle sensor 717 and a line start signal L_Sync from the displacement of the horizontal angle sensor 716, and outputs them to the control unit 713.

  The control unit 713 generates a pixel timing clock based on the linear velocity calculated from the frame start signal F_Sync, the line start signal L_Sync, the vertical synchronization signal, and the horizontal synchronization signal. The pixel timing clock is a signal for knowing the timing at which the laser beam passes on each pixel, and is for causing the laser beam modulated in accordance with the image signal to enter an accurate position. The controller 713 further generates a light source driving pulse signal from the pixel timing clock. With the light source drive pulse signal, it becomes possible to turn on the laser beam at an interval ΔS that substantially matches the distance obtained by subtracting the length dx of the spot SP from the length Px of the pixel P formed in the irradiated region by the image signal. . The laser beam lighting time ton (see FIG. 5) is obtained by dividing the length of ΔS by the linear velocity of the laser beam in each pixel P.

  The R light source drive unit 732R drives the R light source unit 121R based on the image information signal and the light source drive pulse signal for the R light read from the frame memory 714 by the light source control unit 722. The R light source driving unit 732R controls ON / OFF of the R light source unit 121R according to the light source driving pulse signal. The R light source driving unit 732R modulates the R light according to the drive signal whose amplitude is modulated according to the image information signal. The G light source driving unit 732G also drives the G light source unit 121G in the same manner as the R light source driving unit 732R. Similarly to the R light source driving unit 732R, the B light source driving unit 732B drives the B light source unit 121B. Each color light source unit 121R, 121G, 121B is driven according to a drive signal whose amplitude is controlled according to an image signal. Therefore, as shown in FIG. 9, laser light whose intensity is modulated in accordance with the image signal is supplied.

  In this embodiment, a light source driving pulse signal is generated such that the lighting time ton substantially coincides with the time for scanning the laser beam at a distance obtained by subtracting the length dx of the spot SP from the length Px of the pixel P. By setting the lighting time ton as the maximum lighting time, laser light for displaying one pixel can be prevented from entering the pixel area adjacent to the pixel. Furthermore, the lighting time ton may be driven so as to be equal to or shorter than the time for scanning the laser beam at a distance obtained by subtracting the length dx of the spot SP from the length Px of the pixel P. The occurrence of crosstalk between pixels can be reduced by setting the lighting time of the laser light for each pixel to be equal to or shorter than the maximum lighting time. On the other hand, if the lighting time of the laser beam for each pixel is too short, a portion where the intensity of the laser beam is extremely lowered is generated at each pixel boundary. When a dark portion generated at each pixel boundary is recognized by an observer, it is difficult to display a high-quality image.

  FIG. 10 illustrates the minimum lighting time of laser light for displaying one pixel. For example, the timing T2 at which the laser beam is turned off for one pixel can be determined so as to attenuate to the minimum gradation Imin at the timing Tb that passes on the boundary between the pixels P. In this case, at the timing Tb, the intensity Imin of the intensity distribution L2 and the intensity Imin of the intensity distribution L1 'are integrated. It is possible to ensure at least twice the intensity of the minimum gradation Imin at the boundary between the pixels P and make the boundary between the pixels inconspicuous. In this way, the minimum lighting time for displaying one pixel can be determined. The laser light that is turned on to express the gradation of one pixel passes through the boundary between the pixels at a timing that is attenuated to an intensity that is greater than or equal to the intensity that expresses the minimum gradation. An image can be displayed.

  As the modulation according to the image signal, PWM may be used in addition to amplitude modulation. When PWM is used, as shown in FIG. 11, a light source driving maximum pulse signal having the above-mentioned lighting time ton as the maximum pulse width is generated. Then, a light source drive pulse signal whose pulse width is modulated according to the image information signal is generated with the pulse width of the light source drive maximum pulse signal as the maximum gradation. Each of the light source driving units 732R, 732G, and 732B modulates the laser light in accordance with the light source driving pulse signal generated in this way. Each color light source unit is driven according to a light source drive pulse signal whose pulse width is controlled according to an image signal.

  FIG. 12 explains the timing of the light source drive pulse signal. In PWM, the pulse width for turning on the laser beam is changed according to the image signal. For example, it is assumed that a light source drive pulse signal whose rise is simultaneously with the light source drive maximum pulse signal is generated. In this case, the spot is shifted to the left side of the pixel while the laser beam is scanned rightward and to the right side of the pixel while the laser beam is scanned rightward. As described above, when a pulse deviated from one of the rising timing and falling timing of the maximum pulse is generated, a pixel shift occurs between the forward path and the backward path of the laser beam in the X direction.

  Therefore, as shown in FIG. 12, each of the pulses P1, P2, and P3 of the light source driving pulse signal has a pulse width centered at a timing Tc at which the laser beam scans the center position of the pixel in the X direction, which is the first direction. Is set. Each color light source unit is driven in accordance with a pulse signal of a light source driving unit having a pulse width set around the timing Tc at which the laser beam scans the center position of the pixel in the X direction. By setting the pulse width around the timing Tc at which the laser beam scans the center position of the pixel, when the laser beam is reciprocated in the first direction, the incident timing of the laser beam on each pixel can be made uniform. Become. By aligning the incident timing of the laser beam to each pixel, it is possible to reduce the displacement of the pixel position in the X direction. Thereby, it is possible to display a higher quality image with little deviation.

  Even when the intensity distribution of the laser beam in the spot SP is different from the Gaussian distribution, the laser beam lighting time may be set in the same manner as in this embodiment. In this case, according to the intensity distribution of the laser light in the spot SP, the outer edge of the spot SP may be other than a line that attenuates to approximately half the intensity of the peak intensity. By appropriately applying this embodiment, it is possible to reduce the occurrence of crosstalk according to the characteristics of the laser beam from the optical scanning device 120.

  FIG. 13 shows a schematic configuration of an image display apparatus 1700 according to the second embodiment of the present invention. The image display device 1700 is a so-called front projection projector that supplies laser light to a screen 1705 provided on the viewer side and observes an image by observing light reflected by the screen 1705. The image display device 1700 includes the optical scanning device 120 as in the first embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. Laser light from the optical scanning device 120 passes through the projection optical system 103 and then enters the screen 1705. Also in the present embodiment, the occurrence of crosstalk between adjacent pixels can be reduced, and a high-resolution image can be displayed on the screen 1705.

  In the above-described embodiment, each color light source unit is configured to supply laser light. However, the configuration is not limited to this as long as beam-shaped light can be supplied. For example, each color light source unit may be configured to use a solid light emitting element such as a light emitting diode element (LED). Further, the optical scanning device of the present invention may be used in an electronic apparatus that scans laser light, such as a laser printer, in addition to the image display device.

  As described above, the optical scanning device according to the present invention is suitable for use in an image display device that scans light according to an image signal.

1 is a diagram illustrating a schematic configuration of an image display apparatus according to Embodiment 1 of the present invention. The figure which shows schematic structure of a laser apparatus. The figure which shows schematic structure of a scanning part. The figure explaining the structure for driving a scanning part. The figure explaining the shape of a spot and the lighting time of a laser beam. The figure explaining the light source drive pulse signal and the intensity | strength of a laser beam. The figure explaining the intensity | strength of the laser beam on the boundary between pixels. The figure which shows the block structure for controlling an image display apparatus. The figure explaining amplitude modulation. The figure explaining the minimum lighting time of a laser beam. The figure explaining PWM. The figure explaining the timing of a light source drive pulse signal. FIG. 5 is a diagram illustrating a schematic configuration of an image display device according to a second embodiment of the invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Image display apparatus, 101 Laser apparatus, 102 Illumination optical system, 103 Projection optical system, 105 Reflection part, 107 Case, 110 Screen, 120 Optical scanning apparatus, 200 scanning part, 121RR Light source part for 121G G light Light source unit, 121B B light source unit, 124, 125 dichroic mirror, 202 reflecting mirror, 204 outer frame unit, 206 torsion spring, 207 torsion spring, 301, 302 first electrode, 305 mirror side electrode, 306 second Electrode, 307 first torsion spring, 308 second torsion spring, P pixel, SP spot, 711 image signal input unit, 712 synchronization / image separation unit, 713 control unit, 714 frame memory, 715 scanning drive unit, 716 horizontal Angle sensor, 717 Vertical angle sensor, 718 signal Processing unit, 721 Image processing unit, 722 Light source control unit, 723 Scan control unit, 732R R light source driving unit, 732G G light source driving unit, 732R B light source driving unit, 1700 Image display device, 1705 screen

Claims (7)

An optical scanning device that scans a beam according to an image signal,
A light source unit for supplying the light beam;
A scanning unit that scans the beam light from the light source unit in a first direction in a region to be irradiated and a second direction substantially orthogonal to the first direction;
The scanning unit is driven such that a frequency at which the light beam is scanned in the first direction is higher than a frequency at which the light beam is scanned in the second direction.
The light source unit is configured to emit light from the light beam from a length of the first direction of the pixel formed in accordance with the image signal in order to form a single pixel. An optical scanning device that is driven so as to be equal to or shorter than a time during which the beam light is scanned at a distance obtained by subtracting the length of the spot formed in the region in the first direction.   The light source unit is driven so as to express a gradation corresponding to the image signal, and the light beam that is turned on so as to express the gradation of one pixel is higher than an intensity for expressing the minimum gradation. 2. The optical scanning device according to claim 1, wherein the optical scanning device is driven so as to pass through a boundary between the pixels at a timing attenuated to an intensity of 2.   The optical scanning device according to claim 1, wherein the light source unit is driven according to a drive signal whose amplitude is controlled according to the image signal.   3. The optical scanning device according to claim 1, wherein the light source unit is driven in accordance with a drive signal having a pulse width controlled in accordance with the image signal.   5. The light source unit is driven according to a pulse signal in which the pulse width is set around a timing at which the beam light scans the center position of the pixel in the first direction. The optical scanning device according to 1.   6. The light according to claim 1, wherein the light source unit forms the spot having a shape that is longer in the irradiated region than the first direction in the second direction. Scanning device. An image display device that displays an image by light from an optical scanning device,
The image display device according to claim 1, wherein the optical scanning device is the optical scanning device according to claim 1.

Images