WO2005033771A1 - 光スキャナおよびそれを備えた画像形成装置 - Google Patents
光スキャナおよびそれを備えた画像形成装置 Download PDFInfo
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- WO2005033771A1 WO2005033771A1 PCT/JP2004/012964 JP2004012964W WO2005033771A1 WO 2005033771 A1 WO2005033771 A1 WO 2005033771A1 JP 2004012964 W JP2004012964 W JP 2004012964W WO 2005033771 A1 WO2005033771 A1 WO 2005033771A1
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- light
- reflection surface
- optical scanner
- intensity
- incident
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Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
- G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
- G02B26/10—Scanning systems
- G02B26/105—Scanning systems with one or more pivoting mirrors or galvano-mirrors
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
- G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
- G02B26/0816—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements
- G02B26/0833—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/02—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes by tracing or scanning a light beam on a screen
Definitions
- the present invention relates to an optical scanner that scans reflected light from a reflective surface by changing the angle between the reflective surface that reflects the incident light and the incident direction of the incident light.
- the present invention relates to a technique for controlling the intensity of light reflected from a reflection surface.
- an optical scanner that scans light an optical scanner that scans reflected light from the reflecting surface by changing the angle between the reflecting surface that reflects the incident light and the incident direction of the incident light.
- an optical scanner that scans reflected light from the reflecting surface by changing the angle between the reflecting surface that reflects the incident light and the incident direction of the incident light.
- This type of optical scanner is used, for example, in the field of image formation and in the field of image reading.
- it is used for applications such as retinal scanning display devices, projectors, laser printers, and laser lithography that directly display an image by scanning a light beam on the retina, while in the field of image reading.
- optical scanner is a type in which light travels by swinging a reflection surface, and another example is one in which the light is rotated by rotating the reflection surface in one direction. It is a form to do.
- an example of a type in which the reflecting surface is rotated in one direction is an optical scanner that uses a polygon mirror having a plurality of reflecting surfaces adjacent to each other and arranged in a line.
- the optical scanner using the polygon mirror is an optical scanner of the above-described type in which the reflecting surface is swung, in which scanning is repeatedly performed by repeatedly using the same reflecting surface in that scanning is repeatedly performed by sequentially using a plurality of reflecting surfaces.
- the required intensity of the reflected light may not be obtained depending on the angle of the reflection surface with respect to the incident light.
- a photodetector that detects that reflected light from the optical scanner is deflected to a specific angular position is used in order to stabilize scanning start timing.
- a photodetector is usually used when an optical scanner is oriented at an angle out of the angle range of the reflective surface for realizing the intended use of the optical scanner. It is positioned so that reflected light is incident.
- the angle of the reflection surface is different between the case where the light reflected from the reflection surface is incident on the photodetector and the case where the intended use is realized. Therefore, the intensity of the incident light is changed according to the angle of the reflecting surface so that the angle is large at the angle at which the reflected light is incident on the photodetector and small at the angle for realizing the intended use. For example, it is possible to satisfy the requirements from the photodetector and the requirements for realizing the intended use together.
- the present invention scans reflected light from the reflective surface by changing the angle between the reflective surface that reflects the incident light and the incident direction of the incident light.
- the purpose of the present invention is to optimize the intensity of light reflected from the reflection surface of an optical scanner.
- An optical scanner that scans reflected light from the reflecting surface by changing the angle between the reflecting surface that reflects the incident light and the incident direction of the incident light
- An optical scanner including a controller that controls the intensity of the incident light based on a reflection surface angle that is an angle of the reflection surface with respect to the incident direction.
- the intensity of the light incident on the reflection surface is optimized in relation to the angle of the reflection surface, so that the intensity of the light reflected from the reflection surface, that is, the intensity of the scanning light is optimized.
- This optical scanner can be configured as, for example, the above-described swing type or the above-described one-way rotating type.
- the light incident on the reflecting surface can be configured as parallel light with a constant cross-sectional area along the traveling direction, or as convergent light or diffused light with a changing cross-sectional area. It is.
- cross-sectional area means, for example, when the reflected light is a light beam (light beam) having a circular cross section, means the area of a circle corresponding to the beam diameter. A large relationship is established.
- the cross section of the illuminating light is set so that the illuminating light illuminated toward the reflecting surface for traveling runs on the reflecting surface without any loss, and the illuminating light is partially reflected.
- the cross section of irradiation light so that it is not allowed to enter the surface (that is, when the irradiation light includes both required light that is incident light and unnecessary light that is not incident light) Can be considered. Comparing the two cases with each other, as will be described in more detail below, in the former case, the entire limited-reflection surface can be used for light scanning as effectively as possible. It is more difficult in the latter case.
- the irradiation light directed to the reflection surface includes the necessary light incident on the reflection surface and the unnecessary light not incident on the reflection surface, it is possible to allow the existence of the unnecessary light and traverse the irradiation light. Since the surface can be set, it becomes easy to use the entire reflecting surface of a limited area for light traveling as effectively as possible.
- the cross-sectional area of the incident light to the reflection surface that is, the cross-section of the necessary light (that is, the area where the incident light enters the reflection surface) Of the reflecting surface in the incident direction) changes depending on the angle of the reflecting surface with respect to the incident direction of the incident light (hereinafter also referred to as “reflecting surface angle”).
- the projection light is obtained by projecting the cross-sectional area corresponding to the reflection surface of the incident light, that is, the area where the incident light is incident on the reflection surface in the incident direction.
- the area changes according to the angle of the reflecting surface
- the change in the angle of the reflecting surface prevents the intensity of the light reflected from the reflecting surface from changing.
- the "cross-sectional area” means the area of a figure drawn on a plane perpendicular to the optical axis of the incident light.
- the incident light is, for example, a light beam having a circular cross section
- the cross-sectional area means the area of a circle represented by the beam diameter of the light beam, and the relation that the larger the beam diameter is, the larger the cross-sectional area is established. I do.
- the "incident light” in this section can be configured as parallel light having a constant cross-sectional area along its traveling direction, or can be configured as convergent light or diffused light whose cross-sectional area changes. is there.
- the cross-sectional area of the incident light is defined as the cross-sectional area corresponding to the reflecting surface. Is defined.
- the cross-sectional area of the incident light means the projected incident area of the area where the incident light is incident on the reflecting surface (that is, the area on the reflecting surface) in the direction of the incident light. Is formed as convergent light or diffused light, the cross-sectional area of the incident light is geometrically specified.
- the optical scanner is used together with a light source that emits light and modulates the intensity of the emitted light based on a modulation signal, and the controller outputs the modulation signal supplied to the light source to the light source.
- a light source capable of modulating the intensity of the emitted light is used, and the intensity of the light emitted from the light source is modulated, so that the intensity of the light reflected from the reflecting surface is adjusted appropriately.
- the optical scanner is used together with the light source
- the optical scanner means that when the light source is configured as a device independent of the optical scanner, the optical scanner is used together with the light source. Means that However, this does not mean that the optical scanner does not include the light source as one of the components. That is, here, it merely means that the light source is used for operation by the optical scanner, whether or not the optical scanner includes the light source as one of its components. The same applies to the following interpretations.
- the optical scanner is used together with a light source that emits light and a modulator that receives light from the light source and modulates the intensity of the incident light based on a modulation signal.
- the optical scanner according to (1) or (2), wherein the modulation signal supplied to the modulator is controlled based on the reflection surface angle.
- a modulator capable of modulating the intensity of light emitted from the light source is used, and the intensity of light emitted from the light source and trying to enter the reflection surface is modulated. This optimizes the intensity of the light reflected from the reflection surface.
- this optical scanner it is possible to control the intensity of light incident on the reflecting surface without using a light source.
- intensity modulation of incident light is usually performed using at least one of the light sources individually provided for the three primary colors. Therefore, in this case, it is important to take care that the balance between the colors constituting the image does not change before and after the intensity modulation of the incident light.
- the optical scanner according to this section can be implemented in a mode in which a modulator is arranged so as to modulate the intensity of one light beam in which the light beams of the three primary colors are combined. .
- a modulator is arranged so as to modulate the intensity of one light beam in which the light beams of the three primary colors are combined.
- the optical scanner may be embodied in a mode in which the modulator is arranged so that light emitted from the modulator directly enters the reflection surface of the optical scanner without passing through any optical element. It is possible. According to this aspect, the light whose intensity has been accurately modulated by the modulator can be prevented from being adversely affected by another optical element before entering the reflecting surface. Therefore, if this mode is adopted, it becomes easy to accurately modulate the intensity of light incident on the reflection surface.
- An image forming apparatus for forming an image by running a light beam
- a scanning unit having the optical scanner according to any one of (1) to (4) and configured to scan a light beam emitted from the light source;
- An image forming apparatus including: (6) The light source modulates the intensity of a light beam emitted from the light source based on an image signal corresponding to the image, and the controller converts the image signal supplied to the light source to the reflection surface.
- the image signal supplied to the light source is corrected based on the angle of the reflecting surface in order to realize the original use of the image forming, so that the intensity of the reflected light from the reflecting surface is improved. Is optimized.
- This image forming apparatus can be implemented in a mode in which the intensity modulation function of the light source is used for both image formation and optimization of the intensity of reflected light. If this mode is adopted, it is not indispensable to add dedicated hardware for performing intensity modulation in order to optimize the intensity of the reflected light, and the component point of the image forming apparatus due to the optimization of the intensity of the reflected light becomes unnecessary. It is easy to suppress an increase in the number.
- a modulator for modulating the intensity of the emitted light beam based on the modulation signal based on the modulation signal, wherein the controller generates the modulation signal based on the reflection surface angle and generates the modulation signal.
- the intensity of the light reflected from the reflection surface is optimized by controlling the modulator that modulates the intensity of the light beam emitted from the light source based on the reflection surface angle. .
- this image forming apparatus it is possible to perform intensity modulation for optimizing the intensity of reflected light independently of intensity modulation for image formation.
- the light source directs the light beam toward the reflection surface in a state where the light beam has a cross section that generates both necessary light incident on the reflection surface and unnecessary light not incident on the reflection surface.
- the irradiating light is applied so that all the irradiating light applied to the reflecting surface for scanning is completely incident on the reflecting surface.
- the cross section compared to setting the cross section of the irradiation light so that a part of the irradiation light is not allowed to enter the reflection surface, The whole It is difficult to use the light for running as effectively as possible.
- the cross section of the irradiation light is set smaller than the reflection surface.
- the shape of the cross section of the irradiation light and the shape of the reflection surface are close to each other, for example, both the shape of the cross section of the irradiation light and the shape of the reflection surface are circular. Even in the situation where the irradiation light is set so that the irradiation light enters the reflecting surface without leakage, the irradiation light is allowed so that a part of the irradiation light is not allowed to enter the reflecting surface. It is more difficult to use the entire limited-reflection surface for light scanning as effectively as possible than when setting a cross-section of the light.
- the light source has a cross section in which the necessary light incident on the reflecting surface and the unnecessary light not incident on the reflecting surface are generated together. In such a state, the light beam is emitted toward the reflection surface.
- this image forming apparatus it is possible to set the cross section of the light emitted from the light source to the reflecting surface while allowing the presence of the unnecessary light. It is easy to use the entire surface for running light as effectively as possible.
- the "cross section” in this section means a figure drawn on a plane perpendicular to the optical axis of the incident light.
- the incident light is, for example, a light beam having a circular cross section
- the cross section means a circle represented by the beam diameter of the light beam.
- the required light and the unnecessary light are generated by irradiating the light beam toward the reflecting surface. It is not essential to determine the cross section of the light emitted from the light source (ie, the light emitted from the light source toward the reflecting surface) so that it is incident on the entire reflecting surface.
- the cross section of the light emitted from the light source may be determined so that there is a region where the required light does not enter on a part of the reflection surface.
- the running unit includes:
- Main scanning means for causing the light beam emitted from the light source to travel at a high speed in the main scanning direction; and sub-scanning means for causing the light beam emitted from the light source to travel at a low speed in a sub-scanning direction intersecting with the main scanning direction.
- the main scanning means includes the optical scanner according to any one of (1) and (4), wherein the controller is configured to control the reflection surface of the optical scanner in the main scanning means.
- the image forming apparatus according to (8), wherein the intensity of the light beam incident on the reflection surface is controlled based on the reflection surface angle.
- the image forming apparatus As described above, in order to achieve high resolution, it is necessary to enlarge the cross-sectional area of the reflected light from the reflecting surface.
- the image forming apparatus By using the optical scanner described in any of (1) to (4), it becomes easy to give the reflected light a large cross-sectional area for the area of the reflecting surface. This means that the area of the reflecting surface needs to be small compared to the cross-sectional area of the reflected light, and the reflecting mirror on which the reflecting surface is formed can be light. On the other hand, the heavier the reflection mirror part, the lower the scanning frequency of the reflection surface tends to be.
- the running unit that runs the light beam emitted from the light source is a main running unit that runs the light beam at a high speed in the main running direction, and the main running direction thereof.
- the optical scanner according to any one of (1) to (4) is a main scanning device that scans a light beam at a higher speed than the sub-scanning means, that is, at a higher frequency.
- this image forming apparatus it is easy to achieve both improvement in resolution and increase in running frequency in the main running unit, which is more difficult than the sub-running unit.
- FIG. 1 is a system diagram showing a retinal scanning type display device including an optical scanner 104 according to a first embodiment of the present invention.
- FIG. 2 is a perspective view showing the optical scanner 104 in FIG. 1 in an assembled state.
- FIG. 3 is an exploded perspective view showing the optical scanner 104 in FIG. 1.
- FIG. 4 is a longitudinal sectional view showing a part of a vibrating body 124 in FIG. 2.
- FIG. 5 is a perspective view showing a vibrating body 124 in FIG. 2.
- FIG. 6 is a block diagram showing a hardware configuration of a horizontal traveling drive circuit 180 in FIG. 1.
- FIG. 7 is a perspective view for explaining a beam diameter of irradiation light used for the optical scanner 104 in FIG. 2.
- FIG. 8 is an optical path diagram for explaining how the cross-sectional areas of incident light and reflected light change in accordance with the angle of the reflecting surface 120 in FIG.
- FIG. 9 is a graph showing the relationship between the reflection surface angle ⁇ ⁇ ⁇ ⁇ and the intensity of reflected light in the optical scanner 104 in FIG. 1.
- FIG. 10 is a block diagram conceptually showing the overall processing of the retinal scanning display device shown in FIG. 1.
- FIG. 11 is a flowchart conceptually showing the contents of a video signal correction program executed by video signal correction section 240 in FIG. 1 using a computer.
- FIG. 12 is a system diagram showing a retinal scanning display device including an optical scanner 104 according to a second embodiment of the present invention.
- FIG. 13 conceptually shows the overall processing of the retinal scanning display device shown in FIG. It is a figure.
- FIG. 14 is a graph showing the relationship between the reflection surface angle ⁇ ⁇ ⁇ ⁇ and the intensity of reflected light in the optical scanner 104 in FIG.
- FIG. 15 is a flowchart conceptually showing the contents of an intensity modulation program executed by modulation signal output section 262 in FIG. 12 using a computer.
- FIG. 16 is a perspective view for explaining the beam diameter of irradiation light used in the conventional optical scanner 300.
- FIG. 1 systematically shows a retinal scanning display device according to the first embodiment of the present invention.
- This retinal scanning display device (hereinafter abbreviated as “RSD”) forms an image of a retina 14 via a pupil 12 of an observer's eye 10 while appropriately modulating its wavefront and intensity.
- This is a device for projecting an image directly on the retina 14 by causing the laser beam to be incident on a surface, and to be two-dimensionally scanned with a laser beam on the image forming surface.
- the RSD includes a light source unit 20, and includes a running device 24 between the light source unit 20 and the eye 10 of the observer.
- the light source unit 20 includes an R laser 30 that emits red laser light in order to combine three laser lights having three primary colors (RGB) into one laser light to generate an arbitrary color laser light;
- a G laser 32 that emits green laser light and a B laser 34 that emits blue laser light are provided.
- Each of the lasers 30, 32, 34 can be configured as, for example, a semiconductor laser.
- the laser beams emitted from the lasers 30, 32, and 34 are collimated by the collimating optical systems 40, 42, and 44, respectively, in order to combine the laser beams.
- the laser light is made incident on the aperture mirrors 50, 52, and 54, whereby each laser beam is selectively reflected and transmitted with respect to wavelength.
- the red laser light emitted from the R laser 30 is collimated by the collimating optical system 40, and then is incident on the dichroic mirror 50.
- the emitted green laser light is made incident on a dichroic mirror 52 via a collimating optical system 42.
- the blue laser light emitted from the B laser 34 is made incident on the dike opening mirror 54 via the collimating optical system 44.
- the laser beams of the three primary colors that have respectively entered the three dichroic mirrors 50, 52, 54 finally enter one dichroic mirror 54 representing the three dichroic mirrors 50, 52, 54. And then condensed by the coupling optics 56.
- the light source unit 20 includes a signal processing circuit 60 mainly composed of a computer.
- the signal processing circuit 60 is designed to perform signal processing for driving each of the lasers 30, 32, and 34 and signal processing for scanning a laser beam based on an externally supplied video signal. ing.
- the signal processing circuit 60 In order to drive each of the lasers 30, 32, and 34, the signal processing circuit 60 generates a laser beam for each pixel on the image to be projected on the retina 14 based on an image signal supplied from the outside. Driving signals necessary for realizing necessary colors and intensities are supplied to the respective lasers 30, 32, 34 via the respective laser drivers 70, 72, 74. Signal processing for laser beam scanning will be described later.
- the light source unit 20 described above emits a laser beam in the coupling optical system 56.
- the laser beam emitted therefrom travels through an optical fiber 82 as an optical transmission medium and a collimating optical system 84 that collimates the laser beam emitted from the rear end of the optical fiber 82 in that order.
- Light is incident on the device 24.
- the running device 24 includes a horizontal running system 100 and a vertical running system 102.
- the horizontal scanning system 100 is a horizontal scanning that scans a laser beam horizontally along a plurality of horizontal scanning lines for each frame of an image to be displayed (this is an example of main scanning). ).
- the vertical scanning system 102 vertically scans the laser beam from the first scanning line to the last scanning line for each frame of the image to be displayed (this is an example of the sub-scanning).
- the horizontal scanning system 100 is designed to scan the laser beam faster, that is, at a higher frequency than the vertical scanning system 102. Has been.
- the horizontal scanning system 100 is provided with an optical scanner 104 that swings the mirror by vibrating an elastic body having a mirror that performs mechanical deflection.
- the optical scanner 104 is controlled based on a horizontal synchronization signal supplied from the signal processing circuit 60.
- FIG. 2 is a perspective view showing the optical scanner 104 in an assembled state.
- FIG. 3 shows the optical scanner 104 in an exploded perspective view.
- the optical scanner 104 has a main body 110 mounted on a base 112.
- the main body 110 is formed using an elastic material such as silicon. As shown in the upper part of FIG. 3, the main body 110 has a thin rectangular shape having a through hole 114 through which light can pass.
- the main body 110 has a fixed frame 116 on the outside, and a vibrator 124 having a reflection mirror 122 on which a reflection surface 120 is formed on the inside.
- the base 112 includes, as shown in the lower part of FIG. 3, a support portion 130 to which the fixed frame 116 is to be mounted in the mounted state with the main body 110, It is configured to have a vibrating body 124 and a concave portion 132 opposed thereto.
- the concave portion 132 is formed so as to have a shape and shape that does not interfere with the base 112 even when the vibrating body 124 is displaced by vibration in a state where the main body 110 is mounted on the base 112.
- the reflection surface 120 of the reflection mirror unit 122 is swung about a rotation center line 134 which is also a center line of symmetry thereof.
- the vibrating body 124 further includes a beam portion 140 extending from the reflection mirror portion 122 on the same plane as the reflection mirror portion 122 and joining the reflection mirror portion 122 to the fixed frame 116.
- a pair of beams 140 extend from opposite sides of the reflection mirror 122 in opposite directions.
- Each beam portion 140 includes one mirror-side leaf spring portion 142, a pair of frame-side leaf spring portions 144, and a connection for connecting the mirror-side leaf spring portion 142 and the pair of frame-side leaf spring portions 144 to each other.
- Part 146 is configured.
- the mirror side leaf spring portion 142 is formed on the rotation center line 134 on the rotation center line 134 from each of a pair of edges of the reflection mirror portion 122 facing each other in the direction of the rotation center line 134 to the corresponding connection portion 146. Extending along.
- the pair of frame-side leaf spring portions 144 are connected to the rotation center line 134 from the corresponding connection portions 146. And extends along the rotation center line 134 in a posture of being offset in the opposite direction.
- each of the driving sources 150, 152, 154, and 156 is mainly composed of a piezoelectric body 160 (also referred to as a "piezoelectric vibrator” or a “piezoelectric element”).
- the piezoelectric body 160 is attached to one surface of the vibrating body 124 in a thin plate shape, and is sandwiched between the upper electrode 162 and the lower electrode 164 in a direction perpendicular to the attachment surface.
- the upper electrode 162 and the lower electrode 164 are respectively connected to a pair of input terminals 168 provided on the fixed frame 116 by respective lead wires 166.
- the drive sources 150, 152, 154, and 156 attached to the four frame-side leaf springs 144, respectively are located on one side with respect to the rotation center line 134.
- a pair of drive sources 150 and 152 sandwiching the reflection mirror unit 122 and a pair of drive sources 154 and 156 located on the other side and sandwiching the reflection mirror unit 122 are two piezoelectric materials belonging to each pair.
- the 160 free ends are bent so as to be displaced in the same direction as each other.
- a pair of drive sources 150 and 154 located on one side of the reflection mirror unit 122 and sandwiching the rotation center line 134 and a pair of drive sources 152 located on the other side and sandwiching the rotation center line 134 are provided.
- And 156 are bent so that the free ends of the two piezoelectric bodies 160 belonging to each pair are displaced in opposite directions.
- each frame-side leaf spring portion 144 has a function of converting a linear displacement (lateral displacement) of the piezoelectric body 160 attached thereto into a bending motion (longitudinal displacement). It has a function of converting the bending motion of the frame-side leaf spring portion 144 into the rotation motion of the mirror-side leaf spring portion 142.
- the reflecting mirror section 122 is rotated by the rotational movement of the mirror side leaf spring section 142.
- the two driving sources 150 and 152 forming the first pair and the two driving sources 154 and 156 forming the second pair are displaced in directions opposite to each other, so that the reflection mirror section is formed.
- the alternating voltage is applied to the first pair of two driving sources 150 and 152 in the same phase.
- the alternating voltage having the opposite phase is applied to the second pair of the two driving sources 154 and 156 in the same phase.
- the horizontal running system 100 includes a horizontal running drive circuit 180 shown in FIG.
- the oscillator 182 In the horizontal scanning drive circuit 180, as shown in FIG. 6, the oscillator 182 generates an alternating voltage signal based on the horizontal synchronization signal input from the signal processing circuit 60.
- the oscillator 182 is connected to a first pair of two driving sources 150 and 152 via a first path via a phase shifter 184 and an amplifier 186, while passing through a phase inverting circuit 188, a phase shifter 190 and an amplifier 192. Via a second path, it is connected to a second pair of two driving sources 154, 156.
- the phase inversion circuit 188 inverts the phase of the alternating voltage signal input from the oscillator 182 and supplies it to the phase shifter 190. Since the phase inversion circuit 188 is provided only in the second path, the two driving sources 150 and 152 forming the first pair and the two driving sources forming the second pair In 154 and 156, the phases of the alternating voltage signals supplied from the corresponding amplifiers 186 and 192 are opposite to each other.
- phase shifters 184, 190 are provided in any of the paths.
- the laser beam horizontally scanned by the optical scanner 104 described above is transmitted to the vertical scanning system 102 by the relay optical system 194, as shown in FIG.
- This RSD has a beam detector 200 at a fixed position.
- the beam detector 200 is provided to detect the position of the laser beam in the main scanning direction by detecting the laser beam deflected by the optical scanner 104 (that is, the laser beam scanned in the main scanning direction). ing.
- One example of a beam detector 200 is a photo diode.
- the beam detector 200 outputs a signal indicating that the laser beam has reached a predetermined position as a BD signal, and the output BD signal is supplied to the signal processing circuit 60.
- the signal processing circuit 60 waits for a set time from the time when the beam detector 200 detects the laser beam, and outputs a necessary drive signal to each laser driver 70. , 72, 74.
- the image display start timing is determined for each scanning line, and the image display is started at the determined image display start timing.
- the vertical running system 102 includes a galvano mirror 210 as a swing mirror that performs mechanical deflection.
- the laser beam emitted from the horizontal scanning system 100 is condensed by the relay optical system 194 and enters the galvanomirror 210.
- the galvanomirror 210 is swung around a rotation axis that intersects the optical axis of the laser beam incident on the galvanomirror.
- the starting timing and the rotation speed of the galvanometer mirror 210 are controlled based on a vertical synchronization signal supplied from the signal processing circuit 60.
- the relay optical system 214 includes a plurality of optical elements 216 and 218 arranged side by side on the optical path.
- the optical scanner 104 of the present embodiment as shown in FIG. 7, a part of the laser beam having a generally circular cross section irradiated toward the reflection surface 120 is reflected on the reflection surface 120.
- the size of the beam diameter of the laser beam is set so as not to be incident. Specifically, in the present embodiment, the beam diameter is set so that the laser beam is incident on the entire reflecting surface 120, and as a result, the beam diameter becomes larger than the maximum dimension of the reflecting surface 120. I have.
- the cross section 234 of the laser beam directed to the reflecting surface 120 becomes larger than the reflecting surface 120. Therefore, the total irradiation light, which is the laser beam directed to the reflecting surface 120, includes the necessary light that is the incident light that enters the reflecting surface 120 and the unnecessary light that does not enter the reflecting surface 120.
- a cross-sectional area corresponding to the reflection surface 120 of the incident light that is, a projection in which the area where the incident light is incident on the reflection surface 120 is projected in the incident direction.
- the incident area changes as the angle of the reflecting surface 120 with respect to the incident direction (hereinafter, simply referred to as “reflecting surface angle ⁇ ”) changes between the maximum angle and the minimum angle.
- the term “reflection surface angle ⁇ " refers to the incident light in a direction perpendicular to both the incident direction of the incident light and the normal direction of the reflection surface 120 (the direction perpendicular to the paper surface in FIG. 8). And the reflection surface 120, it is defined as the smaller of the two angles formed at the intersection of the optical axis of the incident light and the straight line representing the reflection surface 120.
- FIG. 8 (a) shows that reflection on the reflection surface 120 is performed when the reflection surface angle ⁇ is the maximum angle. This is shown in the optical path diagram. Here, a state in which the cross-sectional area of the incident light corresponding to the reflecting surface 120 is maximized, and accordingly, the cross-sectional area of the reflected light from the reflecting surface 120 is also maximized is shown.
- FIG. 8B shows an optical path diagram in which the reflection on the reflection surface 120 is performed when the reflection surface angle ⁇ is the minimum angle.
- the position of the reflecting surface 120 when the reflecting surface angle ⁇ is the maximum angle is shown by a broken line for comparison.
- a state is shown in which the cross-sectional area of the incident light corresponding to the reflecting surface 120 is minimized, and accordingly, the cross-sectional area of the reflected light from the reflecting surface 120 is also minimized.
- the reflected light since the cross-sectional area corresponding to the reflecting surface 120 of the incident light and the cross-sectional area of the reflected light depend on the reflecting surface angle ⁇ , if no countermeasure is taken, the reflected light also depends on the reflection surface angle ⁇ . Specifically, as shown by the broken line graph in FIG. 9, when the reflection surface angle ⁇ is the maximum angle, the intensity of the reflected light is maximum, while the reflection surface angle ⁇ is the minimum angle. In some cases, the intensity of the reflected light depends on the angle of the reflecting surface ⁇ , such that the intensity of the reflected light is the minimum.
- the intensity of the incident light is controlled based on the reflection surface angle ⁇ .
- this control as shown in FIG. 9, assuming that the intensity of the reflected light when the reflection surface angle ⁇ is a neutral angle is equal to the target intensity, in a region where the reflection surface angle ⁇ is larger than the neutral angle, Dimming correction is performed to reduce the intensity of the incident light.
- Dimming correction is performed to reduce the intensity of the incident light.
- brightening correction for increasing the intensity of the incident light is performed.
- the intensity of the reflected light is maintained to substantially coincide with the target value despite the change in the reflection surface angle ⁇ ⁇ , as shown by the solid line graph in FIG.
- FIG. 10 is a block diagram conceptually showing the overall electrical and optical processing in the RSD according to the present embodiment in chronological order.
- a laser drive signal is generated based on a video signal supplied from the outside, which defines the color and intensity for each pixel in the image, and the laser driver 70, 72, 74 Is output to The lasers 30, 32, and 34 generate laser light in response to the laser drive signal, and the generated laser light is used as a laser beam by the scanning device. Incident on the device 24 where it is scanned. The scanned laser beam is projected on the retina 14 and an image is displayed to an observer.
- the video signal supplied from the outside is changed according to the reflection surface angle ⁇ . It is corrected so that the intensity is modulated.
- the reflection surface angle is detected with reference to the timing at which the beam detector 200 detects the traveling light from the optical scanner 104.
- the signal processing circuit 60 includes the video signal correction unit 240 to correct the video signal.
- the video signal correction unit 240 is configured by a part of the computer of the signal processing circuit 60 that executes a video signal correction program.
- FIG. 11 is a flowchart conceptually showing the contents of the video signal correction program. This video signal correction program is repeatedly executed.
- step S1 (hereinafter simply referred to as "S1"; the same applies to other steps), an external video signal is input as an original video signal.
- step S2 a BD signal indicating whether or not the scanning light from the optical scanner 104 has been detected is input from the beam detector 200.
- the reflection surface angle ⁇ is detected based on the input BD signal.
- the intensity correction amount which is the correction amount of the laser light intensity (incident light intensity) represented by the original video signal
- the intensity correction amount corresponding to the detected reflection surface angle ⁇ is determined as the current intensity correction amount according to the value stored in the computer memory of the signal processing circuit 60 in advance.
- the relationship between the correction amount and the angle is set in consideration of the relationship between the reflection surface angle ⁇ shown in the graph of FIG. 9 and the intensity deviation of the reflected light (the difference between the target intensity and the intensity before correction). I have.
- the input video signal is corrected based on the determined current intensity correction amount. That is, a corrected video signal is generated. Then, in S6, the generated corrected video signal is output to the laser drivers 70, 72, and 74.
- the optical scanner 104 constitutes an example of the “optical scanner” according to the above mode (1), and the signal processing circuit 60 operates as the above (1).
- the controller constitutes an example of the “controller” in any of (3).
- the RSD constitutes an example of the “image forming apparatus” according to the above item (5)
- the light source unit 20 constitutes an example of the “light source” of the above item (6)
- the signal processing circuit 60 forms an example of the “controller” in the same section
- the video signal correction section 240 forms an example of the “signal correction section” in the same section.
- the light source unit 20 constitutes an example of the “light source” in the above item (8)
- the optical scanner 104 constitutes an example of the “main scanning means” in the above item
- the no-mirror 210 forms an example of the “sub-scanning means” in the same section
- the signal processing circuit 60 forms an example of the “controller” in the same section.
- this embodiment differs from the first embodiment only in the elements that control the intensity of the light incident on the reflection surface 120, and therefore, only the different elements will be described in detail.
- the common elements will be referred to using the same reference numerals or names, and will not be described in detail.
- the intensity modulation function of the lasers 30, 32, and 34 is used to control the intensity of the light incident on the reflection surface 120 based on the reflection surface angle 34. Functions required for display are used.
- an AO modulator for modulating the intensity of light incident on the reflection surface 120 is provided between the light source unit 20 and the optical scanner 104.
- 260 are set up.
- No optical element eg, lens, mirror, etc.
- the intensity of the light incident on the reflecting surface 120 is controlled based on the reflecting surface angle ⁇ .
- the signal processing circuit 60 is configured to include a modulation signal output unit 262, and the modulation signal output from the modulation signal output unit 262 By being supplied to the optical device 260, the intensity of the light emitted from the light source unit 20, which is about to enter the optical scanner 104, is modulated.
- FIG. 13 is a block diagram similar to FIG. 10, illustrating the overall processing of the RSD according to the present embodiment.
- the intensity modulation of the light incident on the optical scanner 104 in the horizontal scanning system 100 that runs faster than the vertical scanning system 102 is performed based on the modulation signal. Is determined based on ⁇ .
- the reflection surface angle ⁇ is detected with reference to the BD signal from the beam detector 200, as in the first embodiment.
- the lasers 30, 32, and 34 and the AO modulator 260 have a common force S in that the laser beam intensity can be modulated, and the lasers 30, 32, and 34 increase or decrease the laser beam intensity. It is different from the A ⁇ modulator 260 in that it can be executed only in intensity reduction.
- the modulation signal output unit 262 includes a reflection signal as shown in the graph of FIG.
- the output of the lasers 30, 32 and 34 is set so that the surface angle ⁇ is the minimum angle, that is, the intensity of the reflected light at the time when the intensity of the reflected light is the minimum is equal to the target intensity, If the reflection surface angle ⁇ ⁇ ⁇ ⁇ ⁇ is larger than the minimum angle, the dimming correction is performed so that the intensity of the incident light decreases according to the reflection surface angle ⁇ .
- the modulation signal output unit 262 is configured by a part of the computer of the signal processing circuit 60 that executes an intensity modulation program.
- FIG. 15 is a flowchart conceptually showing the contents of the intensity modulation program. This intensity modulation program is also repeatedly executed.
- BD signal indicating whether or not scanning light from the optical scanner 104 has been detected is input from the beam detector 200.
- the reflection surface angle is detected based on the input BD signal.
- a predetermined modulation amount between one angle and the reflection surface angle ⁇ ⁇ ⁇ between the intensity modulation amount that is the modulation amount of the intensity of the laser beam (the intensity of the incident light) emitted from the light source unit 20 In accordance with the relationship stored in advance in the memory of the computer of the signal processing circuit 60, the intensity modulation amount corresponding to the detected reflection surface angle ⁇ is determined as the current intensity modulation amount.
- the relationship between the modulation amount and the angle is graphically shown in FIG. It is set in consideration of the relationship between the reflection surface angle ⁇ and the intensity deviation of the reflected light (the difference between the target intensity and the intensity before correction).
- a modulated signal is generated based on the determined current intensity modulation amount.
- the generated modulated signal is output to ⁇ modulator 260.
- the optical scanner 104 constitutes an example of the “optical scanner” according to the above item (1)
- the signal processing circuit 60 includes the above (1)
- the AO modulator 260 constitutes an example of the “controller” in the item (2) or (4)
- the AO modulator 260 constitutes an example of the “modulator” in the item (4).
- the RSD constitutes an example of the “image forming apparatus” according to the above item (5)
- the signal processing circuit 60 corresponds to the “controller” in the above item (5) or (7).
- the modulation signal output unit 262 constitutes an example of the “signal output unit” in the above item (7)
- the AO modulator 260 constitutes an example of the “modulator” in the same item.
- the optical scanner 104 in order to stabilize the intensity of the scanning light, that is, the reflected light by the optical scanner 104 and to display an image well, the optical scanner 104 is used.
- the intensity of irradiation light (including necessary light incident on the optical scanner 104 and unnecessary light not incident on the optical scanner 104) is changed according to the reflection surface angle ⁇ .
- the beam detection by the beam detector 200 is ensured, and the intensity of the beam projected on the retina 14 is optimized (for example, the exposure amount of the beam is limited to a degree that is not too dazzling to an observer).
- the present invention can be implemented in a mode in which the intensity of irradiation light to the optical scanner 104 is changed according to the reflection surface angle ⁇ .
- the intensity of the light illuminating the optical scanner 104 is adjusted such that the light is incident on the beam detector 200 at a high intensity while being incident on the retina 14 with a small intensity. It is possible to carry out the present invention in a mode that can be changed according to the conditions.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Theoretical Computer Science (AREA)
- Mechanical Optical Scanning Systems (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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US11/390,102 US7235778B2 (en) | 2003-09-30 | 2006-03-28 | Optical scanner reflecting and outputting light with controlled intensity and image forming apparatus using same |
Applications Claiming Priority (2)
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JP2003-339151 | 2003-09-30 | ||
JP2003339151A JP4023426B2 (ja) | 2003-09-30 | 2003-09-30 | 網膜走査型ディスプレイ装置 |
Related Child Applications (1)
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US11/390,102 Continuation US7235778B2 (en) | 2003-09-30 | 2006-03-28 | Optical scanner reflecting and outputting light with controlled intensity and image forming apparatus using same |
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WO2005033771A1 true WO2005033771A1 (ja) | 2005-04-14 |
Family
ID=34419148
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PCT/JP2004/012964 WO2005033771A1 (ja) | 2003-09-30 | 2004-09-07 | 光スキャナおよびそれを備えた画像形成装置 |
Country Status (3)
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US (1) | US7235778B2 (ja) |
JP (1) | JP4023426B2 (ja) |
WO (1) | WO2005033771A1 (ja) |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
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JP4929965B2 (ja) * | 2006-10-12 | 2012-05-09 | セイコーエプソン株式会社 | アクチュエータ、光スキャナおよび画像形成装置 |
JP2008164489A (ja) * | 2006-12-28 | 2008-07-17 | Nyuurii Kk | レーザ光走査装置が走査するレーザ光の読取装置及び方法 |
JP5320673B2 (ja) * | 2007-01-16 | 2013-10-23 | セイコーエプソン株式会社 | アクチュエータ、光スキャナおよび画像形成装置 |
JP4965284B2 (ja) * | 2007-03-07 | 2012-07-04 | 株式会社リコー | 光走査装置・画像形成装置 |
US7697188B2 (en) * | 2007-12-19 | 2010-04-13 | Silicon Quest Kabushiki-Kaisha | Projection display system for modulating light beams from plural laser light sources |
JP4503076B2 (ja) * | 2008-01-18 | 2010-07-14 | 三菱電機株式会社 | 揺動駆動装置 |
JP5426459B2 (ja) | 2010-04-08 | 2014-02-26 | 株式会社ミツトヨ | マイクロメータ |
JP5978852B2 (ja) | 2012-08-17 | 2016-08-24 | セイコーエプソン株式会社 | 情報端末、携帯情報端末および映像表示システム |
JP6191563B2 (ja) * | 2014-09-01 | 2017-09-06 | 富士電機株式会社 | 光走査装置 |
WO2019135494A1 (ko) | 2018-01-08 | 2019-07-11 | 주식회사 에스오에스랩 | 라이다 장치 |
US10591598B2 (en) | 2018-01-08 | 2020-03-17 | SOS Lab co., Ltd | Lidar device |
KR101977315B1 (ko) * | 2018-05-14 | 2019-05-20 | 주식회사 에스오에스랩 | 라이다 장치 |
KR102050677B1 (ko) | 2018-05-14 | 2019-12-03 | 주식회사 에스오에스랩 | 라이다 장치 |
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JPS6443323U (ja) * | 1987-09-10 | 1989-03-15 | ||
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JPH04255874A (ja) * | 1990-08-20 | 1992-09-10 | Xerox Corp | ラスタ出力スキャナ強度制御の手段及び方法 |
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Also Published As
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JP2005107070A (ja) | 2005-04-21 |
US7235778B2 (en) | 2007-06-26 |
JP4023426B2 (ja) | 2007-12-19 |
US20060169880A1 (en) | 2006-08-03 |
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