JP2009075171A - Adjusting device, method of manufacturing and optical scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily adjust the position of a scanning module with respect to a casing when the scanning module including a micromirror for scanning a light beam is mounted on the casing. <P>SOLUTION: A light beam IL for adjustment emitted from a laser light radiation apparatus 22 is radiated on the micromirror 2 in the scanning module 1 mounted on the casing 50. The beam diameter of the light beam IL for adjustment is larger than the outer diameter of the micromirror 2, and a portion of the beam passes beyond the micromirror and is made incident to a quartered photodiode of a light receiving apparatus 25. When the micromirror 2 is shifted in XY direction with respect to the center of the light beam IL for adjustment, the light quantities received by the respective light receiving regions of the quartered photodiode are different from one another, thus the XY-shift of the micrometer 2 is detected on the basis of the difference in the received light quantity on a shift detection apparatus 26 and the XY-shift is displayed on a monitor 27. An operator drives micrometers MMX1, MMX2, MMXY1 and MMY2 to adjust the XY position of the scanning module 1 on the casing 50. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an adjusting device that adjusts the mounting position of the scanning module with respect to the housing when a scanning module including a micromirror that scans a light beam is attached to the housing, and the manufacture of an optical scanning device using the adjusting device. The present invention relates to a method and an optical scanning device having a scanning module including the micromirror.

  2. Description of the Related Art Conventionally, a scanning module for forming a projected image by scanning a laser beam (light beam) modulated by an image signal is known (see, for example, Patent Document 1). This type of scanning module is used, for example, in the field of image formation and the field of image reading. In the field of image formation, it is used in a retinal scanning display device, a projector, a laser printer, laser lithography, and the like that scan a light beam on the retina and directly display an image. On the other hand, in the field of image reading, it is used for facsimiles, copying machines, image scanners, bar code readers and the like.

The scanning module described in Patent Document 1 includes a small mirror (micromirror) and a vibrating body for torsionally vibrating the micromirror. Due to the oscillation of the micromirror by the vibrating body, the light reflected by the reflection surface of the micromirror is scanned in one direction.
JP-A-11-203383

  In this type of scanning module, in order to efficiently perform one-dimensional scanning of reflected light, it is desirable that the light beam is always incident on the same position on the reflecting surface of the micromirror. For this purpose, it is necessary that the center of the cross section of the light beam and the center of the micromirror coincide. In order to make the centers coincide, it is necessary to adjust the position of the micromirror on the casing when the scanning module is attached to the casing of the apparatus in the manufacturing process of the apparatus in which the scanning module is incorporated.

  However, such a micromirror is very small, and the position adjustment is very difficult and time-consuming work. Further, the orientation of the micromirrors in the scanning module varies depending on the scanning module, and the variation makes it difficult to adjust the micromirrors.

  The present invention has been made in order to solve the above-described problem, and an adjustment device capable of easily realizing the adjustment of matching the center of the cross section of the light beam with the center of the micromirror that scans the light beam, It is an object of the present invention to provide an optical scanning device manufacturing method using the adjusting device and an optical scanning device suitable for the adjusting device and the manufacturing method.

  In order to achieve the above object, the adjustment device according to claim 1 includes a micromirror that scans a light beam, and the shape of the micromirror is 2 m (m is an integer of 2 or more) with the cross-sectional central axis as a symmetry axis. An adjustment device that adjusts the mounting position of the scanning module with respect to the housing when the scanning module configured to be rotationally symmetric is attached to the housing, and positions the housing at a predetermined position. And a stage for mounting the scanning module on the casing, and an adjustment light beam in which the effective diameter of the beam is at least larger than the diameter of the maximum circumscribed circle determined for the mirror shape A light beam irradiating unit that irradiates a micromirror in the scanning module placed on the housing, and the adjustment optical beam that has passed outside the micromirror. A displacement detection unit that detects a displacement of the center of the micromirror with respect to a beam cross-sectional center of the adjustment light beam, and the scanning on the housing based on the displacement detected by the displacement detection unit. And an adjustment unit for adjusting the position of the module.

  According to a second aspect of the present invention, in the adjustment device according to the first aspect, the displacement detector receives the adjustment light beam that has passed outside the micromirror, and depends on the amount of light received. And a photoelectric conversion means for outputting an electrical signal, wherein the displacement of the center of the micromirror with respect to the cross-sectional center of the adjustment light beam is detected based on the electrical signal output from the photoelectric conversion means. .

  According to a third aspect of the present invention, there is provided the adjusting device according to the second aspect, wherein the light receiving surface of the photoelectric conversion means is 2n (n is a rotational symmetry about the center of the cross section of the adjusting light beam). (An integer greater than or equal to 2) regions, and detecting the displacement of the center of the micromirror with respect to the cross-sectional center of the adjustment light beam according to the difference in the amount of light received in each of the divided regions. Features.

  According to a fourth aspect of the present invention, in the adjustment device according to the third aspect, the light receiving surface of the photoelectric conversion means is divided into four regions that are rotationally symmetric.

  According to a fifth aspect of the present invention, in the adjustment device according to the second aspect, the displacement detection unit is configured such that each of the light receiving surfaces is 2n (n is 1 or more) with the cross-sectional center of the adjustment light beam as a center. 2n photoelectric conversion means arranged rotationally symmetrically, and based on the difference in the amount of light received by each photoelectric conversion means, the displacement of the center of the micromirror with respect to the cross-sectional center of the adjustment light beam It is characterized by detecting.

  The adjustment device according to claim 6 is the adjustment device according to claim 2, wherein the photoelectric conversion means receives the adjustment light beam that has passed through the outside of the micromirror and corresponds to the light reception result. An image sensor that outputs an image data signal to be detected, wherein the displacement of the center of the micromirror with respect to the cross-sectional center of the adjustment light beam is detected based on the image data signal output from the image sensor .

  According to a seventh aspect of the present invention, in the adjustment device according to the second aspect, the photoelectric conversion means is an element in which a resistance layer is provided on the surface of the photodiode.

  The adjusting device according to claim 8 is the adjusting device according to any one of claims 1 to 7, wherein the adjusting unit includes an actuator, and the actuator is driven to drive the adjusting device. Displacement is given by contact-pressing the scanning module, and the position of the scanning module on the housing is adjusted.

  The adjustment device according to claim 9 is the adjustment device according to claim 8, wherein the adjustment unit is provided with two actuators opposite to each other in directions in which the micromirror is displaced. It is characterized by being.

  An adjustment device according to a tenth aspect is the adjustment device according to the eighth or ninth aspect, wherein the actuator is a piezoelectric element.

  The manufacturing method according to claim 11 includes a housing and a micromirror that scans a light beam, and the shape of the micromirror is shortened by 2 m (m is an integer of 2 or more) with respect to the central axis of the cross section. A method of manufacturing an optical scanning device having a scanning module configured to be rotationally symmetric, wherein a beam is applied to a micromirror in the scanning module placed on a housing positioned at a predetermined position. An irradiation step of irradiating an adjustment light beam having an effective diameter that is at least larger than a diameter of a maximum circumscribed circle determined for the mirror shape; and the adjustment light beam that has passed outside the micromirror. Based on a displacement detection step of detecting a displacement of the center of the micromirror with respect to the beam cross-sectional center of the adjustment light beam, and a change detected by the displacement detection step. Based on the position of the scanning module on the housing, characterized in that it comprises a, an adjustment step of adjusting by using an actuator.

  The manufacturing method according to claim 12 further includes a step of fixing the scanning module to the casing after the adjustment step is performed in the manufacturing method according to claim 11. .

  The optical scanning device according to claim 13 is configured so that the shape is substantially rotationally symmetric by 2 m (m is an integer of 2 or more) with respect to the central axis of the cross section, and the light beam is reflected by the reflection of the cross section. When the adjustment light beam, which is larger than the diameter of the maximum circumscribed circle determined at least with respect to the mirror shape, is incident on the micromirror, the adjustment light is scanned. A frame that allows the beam to pass from the outside of the micromirror and holds the micromirror in a swingable manner.

  The optical scanning device according to claim 14 is the optical scanning device according to claim 13, wherein the frame can be mounted and the adjustment that has passed outside the micromirror held by the mounted frame. The apparatus further includes a housing having a light passage portion that further allows the light beam to pass therethrough.

  According to the adjustment device of the first aspect, in a state where the housing is positioned at a predetermined position and the scanning module is placed on the housing, the micromirror included in the scanning module is The adjustment light beam having a beam diameter that is practically determined is larger than the diameter of the maximum circumscribed circle determined for the shape of the micromirror. The displacement detection unit detects the displacement of the center of the micromirror with respect to the beam cross-sectional center of the adjustment light beam based on the adjustment light beam that has passed outside the micromirror. Further, the adjustment unit adjusts the position of the scanning module on the housing based on the detected displacement.

  That is, in this adjustment device, the displacement of the center of the micromirror with respect to the beam cross-sectional center of the adjustment light beam is detected based on the adjustment light beam that has passed through the outside of the micromirror. Therefore, the displacement of the center of the micromirror can be detected with high accuracy. Further, the position of the scanning module on the housing is adjusted based on the detected displacement, and the center of the cross section of the adjustment light beam and the center of the micromirror can be easily matched.

  According to the adjustment device of the second aspect, the displacement detection unit includes a photoelectric conversion unit that receives the adjustment light beam that has passed through the outside of the micromirror and outputs an electrical signal corresponding to the received light amount. Therefore, the displacement of the center of the micromirror with respect to the center of the cross section of the adjustment light beam can be detected based on the electrical signal output from the photoelectric conversion means.

  According to the adjustment device of the third aspect, the light receiving surface of the photoelectric conversion means is divided into 2n (n is an integer of 2 or more) regions that are rotationally symmetric about the center of the cross section of the adjustment light beam. Therefore, the difference in the amount of light received in each divided region represents the displacement of the center of the micromirror with respect to the center of the cross section of the adjustment light beam. Therefore, the displacement of the center of the micromirror with respect to the center of the cross section of the adjustment light beam can be detected from the difference in the amount of light received in each divided region.

  According to the adjustment device of the fourth aspect, the light receiving surface of the photoelectric conversion means is divided into four regions that are rotationally symmetric about the center of the cross section of the adjustment light beam. Can detect the displacement of the center of the orthogonal biaxial micromirror with respect to the cross-sectional center of the adjustment light beam.

  According to the adjustment device of the fifth aspect, the displacement detectors are arranged such that the mutual light receiving surfaces are rotationally symmetrical by 2n (n is an integer of 1 or more) times around the center of the cross section of the adjustment light beam. Since 2n photoelectric conversion means are provided, the difference in the amount of light received by each photoelectric conversion means represents the displacement of the center of the micromirror with respect to the cross-sectional center of the adjustment light beam. From the difference in the amount of light received by each photoelectric conversion element, the displacement of the center of the micromirror with respect to the center of the cross section of the adjustment light beam can be detected.

  According to the adjustment device of the sixth aspect, the photoelectric conversion means is an imaging element that receives the adjustment light beam that has passed through the outside of the micromirror and outputs an image data signal corresponding to the light reception result. Based on the image data signal output from the image sensor, the displacement of the center of the micromirror with respect to the center of the cross section of the adjustment light beam is detected. This image data signal is a signal corresponding to the image of the micromirror by the adjustment light beam. Therefore, the displacement of the center of the micromirror with respect to the cross-sectional center of the adjustment light beam can be detected from the image data signal.

  According to the adjustment device of the seventh aspect, the photoelectric conversion means is an element in which a resistance layer is provided on the surface of the photodiode, and the adjustment light beam is based on an electric signal output from the element. The displacement of the center of the micromirror with respect to the center of the cross section is detected. This electrical signal is a signal corresponding to the light receiving position of the adjustment light beam that has passed outside the micromirror. Therefore, the displacement of the center of the micromirror with respect to the cross-sectional center of the adjustment light beam can be detected from the electrical signal.

  According to the adjustment device of the eighth aspect, the adjustment unit has the actuator, and adjusts the position of the scanning module on the housing by driving the actuator and pressing the scanning module on the housing. To do. Therefore, it is possible to make the center of the cross section of the adjustment light beam coincide with the center of the micromirror.

  According to the adjustment device of the ninth aspect, since the two actuators whose directions of displacing the micromirrors are opposite to each other are provided so as to face each other, the micromirror can be seen from the + side and the-side. This makes it possible to adjust the position of the lens, and it is possible to perform positioning at higher speed and more accurately.

  According to the adjustment device of the tenth aspect, the actuator of the adjustment unit is a piezoelectric element, and the position of the scanning module on the casing is adjusted by driving the piezoelectric element and pressing the scanning module on the casing. adjust. Since the piezoelectric element is an actuator that can be micro-driven to be controlled, the position of the micro mirror can be finely adjusted.

  According to the manufacturing method of the eleventh aspect, the housing is positioned at a predetermined position, and the scanning module is placed on the housing. The micromirror included in the scanning module is irradiated with an adjustment light beam having a beam diameter that is effectively determined larger than the diameter of the maximum circumscribed circle determined for the shape of the micromirror. Next, based on the adjustment light beam that has passed through the outside of the micromirror, a displacement of the center of the micromirror with respect to the beam cross-sectional center of the adjustment light beam is detected. Further, the position of the scanning module on the housing is adjusted based on the detected displacement. As a result of this adjustment, the center of the micromirror can be made coincident with the center of the cross section of the designed light beam.

  According to the manufacturing method of claim 12, since the scanning module is fixed to the housing after the position of the scanning module on the housing is adjusted, the center of the beam cross section of the light beam and the center of the micromirror The scanning module can be fixed to the housing in a state in which these are matched.

  According to the optical scanning device of the thirteenth aspect, the frame that holds the micromirror has an effective diameter of the beam that is at least larger than a diameter of a maximum circumscribed circle determined for the shape of the micromirror. Since the large adjustment light beam is passed from the outside of the micromirror, the adjustment light beam that has passed the outside of the micromirror can be received as it is. Therefore, this optical scanning device is suitable for detecting the displacement of the center of the micromirror with respect to the center of the cross section of the adjustment light beam.

  According to the optical scanning device of the fourteenth aspect, since the casing further passes the adjustment light beam that has passed through the outside of the micromirror held by the frame, the adjustment light that has passed through the outside of the micromirror. The beam can be received as it is. Therefore, this optical scanning device is suitable for detecting the displacement of the center of the micromirror with respect to the center of the cross section of the adjustment light beam.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  The optical scanning device adjusted by the adjusting device according to the embodiment of the present invention is used in, for example, a retinal scanning display device. FIG. 1 is a schematic diagram illustrating a schematic configuration of a retinal scanning display device 100. The retinal scanning display device 100 is a device that directly forms an image on the retina F of the eyeball E of the observer.

  As shown in FIG. 1, the retinal scanning display device 100 includes a light source unit 10, an optical fiber 11, a collimating optical system 12, a scanning module 1, a first relay optical system 13, a galvano mirror 14, A second relay optical system 15, a horizontal scanning drive circuit 16, a photo sensor 17, and a vertical scanning drive circuit 18 are provided. Here, the scanning module 1 is an example of an optical scanning device, and is adjusted by an adjusting device 200 in FIG. 3 to be described later.

  In FIG. 1, the light source unit 10 includes a laser that emits blue laser light, a laser that emits green light, and a laser that emits red light (all not shown). The light source unit 10 combines the laser beams emitted from the lasers based on the input video signal to generate video light. The light source unit 10 emits the generated image light toward the collimating optical system 12 via the optical fiber 11. The collimating optical system 12 converts the image light emitted from the light source unit 10 through the optical fiber 11 into parallel light.

  The image light from the collimating optical system 12 is applied to the micromirror 2 of the scanning module 1. The micromirror 2 oscillates at a constant cycle, and by this oscillation, the image light is reflected and scanned in the horizontal direction.

  The horizontally scanned image light is applied to the galvanometer mirror 14 via the first relay optical system 13. The galvanometer mirror 14 reflects the image light and scans in the vertical direction by the swing of the mirror surface by the magnetic field. The vertically scanned image light is imaged on the retina F of the eyeball E via the second relay optical system 15.

  The light source unit 10 outputs a horizontal synchronizing signal to the horizontal scanning driving circuit 16 and outputs a vertical synchronizing signal to the vertical scanning driving circuit 18. The horizontal scanning driving circuit 16 outputs a driving signal to the scanning module 1 based on the horizontal synchronizing signal, and swings the micro mirror 2. The oscillation in this case is based on the resonant oscillation of the micromirror 2. The vertical scanning drive circuit 18 supplies a magnetic field to the galvanometer mirror 14 based on the vertical synchronization signal, and swings the galvanometer mirror 14. The photosensor 17 receives a part of the light horizontally scanned by the horizontal scanning drive circuit 16, converts it into an electric signal, and outputs it to the light source unit 10. The light source unit 10 detects the timing of horizontal scanning using the electrical signal input from the photosensor 17, and determines the start timing of the video signal based on the detected timing.

  In the retinal scanning display device 100, vertical scanning is performed using the galvanometer mirror 14, but the scanning module 1 can be used instead. The frequency of vertical scanning is about 60 Hz, for example. Therefore, the swinging of the mirror part is performed by the twist angle control by the electric signal without using the resonance vibration.

  FIG. 2 is an exploded perspective view showing the configuration of the scanning module 1. As shown in FIG. 2, the scanning module 1 includes a scanner 9 having a micromirror 2 having a substantially circular reflection surface (cross section), a pedestal 5 constituting a swinging space, and a ceramic substrate 6. ing. The scanner 9 holds the micromirror 2 via the support portion 4 so that the micromirror 2 that performs the swing motion, the support portion 4 that forms the swing axis of the micromirror 2, and the microphone mirror 2 can swing. A frame portion (frame) 3 is provided.

  In the scanner 9 of the scanning module 1, the micromirror 2, the support portion 4, and the frame portion 3 are integrally formed. For example, these are formed in a lump through a photolithography process and an etching process on a semiconductor substrate. The frame portion 3 is formed so as to surround the micromirror 2 and is fixed to the upper surface of the pedestal 5. A stepped portion 8 is formed on the frame-shaped pedestal 5, and a region corresponding to the stepped portion 8 is a beam portion 7. The micromirror 2 is held by the beam portion 4 via the support portion 4. Has been.

  A piezoelectric body (not shown) is bonded and fixed to the boundary (see the dotted line shown in FIG. 2) between the beam portion 7 and the other portions in the frame portion 3, and an alternating voltage is applied to the piezoelectric body. The beam part 7 vibrates by vibrating. The vibration of the beam portion 7 is transmitted to the support portion 4, and the micro mirror 2 swings around the support portion 4 as the swing axis (X axis).

  The substrate 6 is a base for holding the scanner 9 and the base 5 and has a frame shape.

  As described above, the micromirror 2 performs one-dimensional scanning of image light by swinging a substantially perfect reflection surface within a predetermined angle range. In order to perform one-dimensional scanning of image light with high accuracy, the projection light is always incident on the same position in the reflection surface of the micromirror 2 even if the micromirror 2 is swung. desirable. Otherwise, since the reflecting surface has a surface shape, the scanning direction of the image light changes slightly. In order to make the projection light always enter the same position in the reflection surface of the micromirror 2, the center of the cross section of the image light incident on the reflection surface of the micromirror 2 being oscillated and the reflection of the micromirror 2 are reflected. The center of the surface must match. In order to make the center of the beam cross section of the image light coincide with the center of the reflection surface of the micromirror 2, the scanning module 1 scans on the casing before being fixed on the casing of the retinal scanning display device 100. It is necessary to adjust the position of the module 1.

  FIG. 3 is a diagram illustrating a configuration of an adjustment device 200 according to an embodiment of the present invention for adjusting the scanning module 1 on the housing when the scanning module 1 is attached to the housing. As shown in FIG. 3, the adjustment device 200 includes an LD control circuit 21, a laser beam irradiation device 22, a stage ST, four micrometers MMX1, MMX2, MMY1, MMY2, a light receiving device 25, and a displacement detection device. 26 and a monitor 27. The light receiving device 25 and the displacement detection device 26 constitute a displacement detection unit, and the four micrometers MMX1, MMX2, MMY1, and MMY2 constitute an adjustment unit.

  The LD control circuit 21 drives the light emitting diode 23 of the laser light irradiation device 22 to emit laser light from the light emitting diode 23 in the −Z direction. This laser light is converted into parallel light having a predetermined cross-sectional shape by the collimating lens 24 of the laser light irradiation device 22 and emitted in the −Z direction. The beam cross section of the parallel light (hereinafter referred to as “adjustment light beam IL”) has a substantially perfect circle shape, and the diameter thereof is larger than the diameter of the reflection surface of the micromirror 2.

  The stage ST has a frame shape and is installed on a body (not shown) of the adjusting device. The adjustment light beam IL emitted from the laser beam irradiation device 22 can pass through the frame of the stage ST. Further, above the stage ST, two micrometers MMX1 and MMX2 along the X-axis direction and two micrometers MMY1 and MMY2 along the Y-axis direction are respectively attached to the body of the adjusting device 200. .

  The light receiving surface of the light receiving device 25 faces the + Z direction, and is provided so as to receive the adjustment light beam IL that has passed through the frame of the stage ST. A photodiode is provided on the light receiving surface of the light receiving device 25. The laser light emitted from the laser light irradiation device 22 enters the photodiode. In this photodiode, the light receiving region is divided into four. The light receiving areas divided into four are arranged so as to be rotationally symmetric with respect to the center of the cross section of the adjustment light beam IL incident on the light receiving surface.

  The light receiving device 25 outputs four electrical signals corresponding to the amounts of received light in the four light receiving regions to the displacement detecting device 26. The displacement detection device 26 detects the difference in the amount of light received in each light receiving region of the light receiving device 25 based on each electrical signal, and based on the difference in the amount of received light, the object (main book) placed on the stage ST is detected. In the embodiment, the displacement of a micromirror 2) described later is detected. The monitor MT displays the detection result (XY displacement of the micromirror 2).

  The micrometer MMX1 has its head facing the + X direction. When the operator operates the micrometer MMX1, the object that contacts the head can be pressed in the + X direction. The micrometer MMX2 has its head facing the -X direction. When the operator operates the micrometer MMX2, the object that contacts the head can be pressed in the -X direction. The head of the micrometer MMY1 faces the + Y direction. If the operator operates the micrometer MMY1, the object that contacts the head can be pressed in the + Y direction. The micrometer MMY2 has its head facing the -Y direction. If the operator operates the micrometer MMY2, the object that contacts the head can be pressed in the -Y direction.

  The laser beam irradiation device 22, the stage ST, and the light receiving device 25 are fixed to a machine body that holds the micrometers MMX1, MMX2, MMY1, and MMY2, and their positional relationship is fixed.

  Next, a method for manufacturing an optical scanning device according to an embodiment of the present invention using the adjusting device 200 will be described. Here, the optical scanning device includes the above-described scanning module 1, a casing and a fixture that will be described later. FIG. 4 is a flowchart showing this manufacturing method.

  As shown in FIG. 4, first, in step S1, the housing is positioned. Here, as shown in FIG. 5, the casing 50 of the retinal scanning display device 100 is installed on the stage ST. The casing 50 is partially bent, and is installed so that the bent portion is in contact with the + X side end of the stage ST. Thereby, the housing | casing 50 comes to be positioned in a predetermined position. When the housing 50 is positioned at this position, the positional relationship between the housing 50 and the adjustment light beam IL is determined. The adjustment light beam IL is set so as to pass through a position corresponding to the incident position of the projection light after assembling the retinal scanning display device 100. The adjustment light beam IL is a reference for mounting the scanning module 1 on the housing 50. Become.

  Returning to FIG. 4, in the next step S2, the fixing bracket is placed. Here, as shown in FIG. 6, the fixing bracket 51 is placed on the housing 50. The fixing metal 51 is a frame-shaped frame. The both ends of the fixing metal 51 in the X-axis direction are bent to the + Z side, and both ends in the Y-axis direction are bent to the −Z side. The width of the housing 50 in the Y-axis direction and the width of the fixing bracket 51 in the Y-axis direction are the same. When the fixing bracket 51 is placed on the housing 50, the Y-axis direction both end portions 51Y of the fixing bracket 51 have a convex shape. Directional movement is completely restricted. As a result, the fixing bracket 51 can slide on the housing 50 only in the X-axis direction.

  Returning to FIG. 4, in the next step S3, the scanning module is mounted. Here, as shown in FIG. 6, the scanning module 1 is placed on a fixing bracket 51 mounted on the housing 50. The width of the fixture 51 in the X-axis direction and the width of the scanning module 1 in the X-axis direction are the same. When the scanning module 1 is placed on the fixing bracket 51, the X-axis direction both end portions 51X of the fixing bracket 51 have a convex shape. Directional movement is completely restricted. As a result, the scanning module 1 can slide on the fixture 51 only in the Y-axis direction.

  Returning to FIG. 4, in the next step S4, the micrometer is adjusted. Here, as shown in FIG. 7, the installation positions of the micrometers MMX1 and MMX2 are adjusted so that the head portions of the micrometers MMX1 and MMX2 are in contact with both end portions 51X in the X-axis direction of the fixing bracket 51, and the micrometer MMY1 The installation positions of the micrometers MMY1 and MMY2 are adjusted so that the head portions of the MMY2 come into contact with both ends of the scanning module 1 in the Y-axis direction. Accordingly, when the micrometer MMX1 is driven, the fixing bracket 51 and the scanning module 1 are pressed and moved in the + X direction, and when the micrometer MMX2 is driven, the fixing bracket 51 and the scanning module 1 are moved in the −X direction. It is pushed and moves. On the other hand, when the micrometer MMY1 is driven, the scanning module 1 is pressed and moved in the + Y direction, and when the micrometer MMY2 is driven, the scanning module 1 is pressed and moved in the + Y direction.

  The fixing bracket 51 and the scanning module 1 are placed in a roughly positioned state so that the laser light emitted from the laser light irradiation device 22 strikes the micromirror 2 in the scanning module 1. There is a need.

  Returning to FIG. 4, in the next step S5, displacement detection is performed. First, the adjustment light beam IL is emitted from the laser light irradiation device 22 via the LD control circuit 21. The adjustment light beam IL is applied to the micromirror 2 in the scanning module 1 placed on the housing 50. Since the diameter of the cross section of the adjustment light beam IL is larger than the diameter of the reflection surface of the micromirror 2, the light beam of the adjustment light beam IL that passes outside the outer periphery of the micromirror 2 passes through as it is. It enters the quadrant photodiode.

  FIG. 8A is a diagram illustrating an example of a state in which the adjustment light beam IL is incident on the quadrant photodiode of the light receiving device 25. Here, in the four-divided photodiode of the light receiving device 25, a region arranged on the + X side among the four divided regions is a light receiving region A, and a region arranged on the −X side is a light receiving region C. The region disposed on the + Y side is referred to as a light receiving region B, and the region disposed on the −Y side is referred to as a light receiving region D.

  As shown in FIG. 8A, since the micromirror 2 is present on the optical path of the adjustment light beam IL, the cross-sectional shape of the adjustment light beam IL incident on the four-divided photodiode is substantially annular. . Here, in order to simplify the explanation, it is assumed that the support portion 4 that forms the swing axis of the micromirror 2 is sufficiently thin and does not affect the light receiving state of the adjustment light beam IL in the light receiving device 25. In FIG. 8A, the center of the cross section of the adjustment light beam IL coincides with the center of the micromirror 2, and the ring of the adjustment light beam IL in which the cross sectional shape incident on the quadrant photodiode is annular. Of the light receiving regions A and C are the same, and the light receiving amounts of the light receiving regions B and D are the same.

  FIG. 8B is a diagram illustrating an example of a state in which the center of the micromirror 2 is displaced in the + X direction and the + Y direction with respect to the cross-sectional center of the adjustment light beam IL. As shown in FIG. 8B, when the position of the micromirror 2 is displaced to the + X side, the amount of light received by the light receiving region A located on the + X side is reduced, and the light received on the −X side. The amount of light received in region C increases. Further, when the position of the micromirror 2 is displaced to the + Y side, the amount of light received by the light receiving region B located on the + Y side is reduced, and the amount of light received by the light receiving region D located on the −Y side is increased. .

  The displacement detection device 26 inputs an electrical signal corresponding to the amount of light received in each of the light receiving areas A to D. Then, the displacement detection device 26 obtains the difference between the received light amounts based on the electrical signal corresponding to the received light amount in the light receiving region A and the electrical signal corresponding to the received light amount in the light receiving region C, and based on the difference. Thus, the X displacement of the micromirror 2, that is, the X displacement of the scanning module 1 is detected. In addition, based on the electric signal corresponding to the amount of light received in the light receiving region B and the electric signal corresponding to the amount of light received in the light receiving region D, the difference in the amount of received light is obtained. The Y displacement, that is, the Y displacement of the scanning module 1 is detected. The X displacement and Y displacement of the scanning module 1 are displayed on the monitor MT.

  If there is an error between the center of the micromirror 2 on the basis of the outer shape and the point that should coincide with the center of the beam cross section due to a manufacturing error of the micromirror 2, the scanning module is considered in consideration of the error. One X displacement and Y displacement may be calculated.

  Returning to FIG. 4, in the next step S6, the position of the scanning module is adjusted. The operator looks at the monitor 27 and operates the micrometers MMX1, MMX2, MMY1, and MMY2 to adjust the XY position of the scanning module. For example, as shown in FIG. 8B, when the amount of light received in the light receiving region A is small and the amount of light received in the light receiving region C is large, the displacement amount in the + X direction is displayed. The operator operates the micrometer MMX2 to shift the scanning module 1 in the −X direction. Further, when the amount of light received in the light receiving region B is small and the amount of light received in the light receiving region D is large, the displacement amount in the + Y direction is displayed. The operator operates the micrometer MMY2 to move the scanning module 1 by the amount of displacement in the −Y direction. If it does in this way, it will be in the state shown in Drawing 8 (A), and the center of micromirror 2 will come in agreement with the section center of light beam IL for adjustment.

  Finally, in step S7, the scanning module is fixed. Here, an adhesive such as a UV curing agent is injected between the scanning module 1 and the fixing bracket 51 or between the fixing bracket 51 and the housing 50 and irradiated with ultraviolet rays. Is fixed on the housing 50. Thereby, after the assembly of the retinal scanning display device 100 is finally completed, the center of the beam cross section of the projection light coincides with the center of the micromirror in the scanning module 1, so that the micromirror 2 vibrates. However, the projection light is incident at the same position on the reflection surface, and the one-dimensional scanning of the reflection light is not affected by the surface shape of the micromirror 2, so that the projection light can be scanned with high accuracy. Realized.

  As described above in detail, according to the present embodiment, the scanning module 50 is positioned in a predetermined position on the stage ST and the scanning module 1 is placed on the housing 50. 1 is irradiated with an adjustment light beam IL having a substantially circular cross section in which the beam diameter is larger than the diameter of the substantially circular reflecting surface of the micromirror 2. The displacement detection device 26 detects the displacement of the center of the micromirror 2 with respect to the beam cross-sectional center of the adjustment light beam IL based on the amount of light received by the adjustment light beam IL that has passed outside the micromirror 2. Furthermore, based on the detected XY displacement, the position of the scanning module with respect to the housing 50 is adjusted using the micrometers MMX1, MMX2, MMY1, and MMY2. As a result, the center of the micromirror 2 can be matched with the center of the beam cross section of the projection light.

  Since the micromirror 2 swings around the X axis as a base axis, there is a possibility that the reflection surface of the micromirror 2 is not parallel to the XY plane. According to the present embodiment, even if the reflection surface of the micromirror 2 is slightly inclined, the micro-axis with respect to the beam cross-sectional center of the adjustment light beam IL is based on the adjustment light beam IL that has passed through the outside of the micromirror 2. The center displacement of the mirror 2 can be detected with high accuracy.

  Note that the shape of the reflection surface of the micromirror 2 may not be a substantially perfect circle shape, and it may be approximately 2m (m is an integer of 2 or more) rotational symmetry with the central axis of the reflection surface as the axis of symmetry. . For example, it may be a square, a regular hexagon, or a regular octagon.

  The effective diameter of the adjustment light beam IL only needs to be larger than the diameter of the maximum circumscribed circle determined for the shape of the reflecting surface of the micromirror 2. For example, when the shape of the reflection surface of the micromirror 2 is substantially rotationally symmetric four times (m = 2, the shape of the reflection surface of the micromirror 2 is square), the effective diameter of the adjustment light beam IL is When a circumscribed circle including the four vertices of the square micromirror 2 on the circumference is formed, the diameter only needs to be larger than the diameter of the circumscribed circle.

  Further, the cross-sectional shape of the adjustment light beam IL may not be a substantially perfect circle shape, and may be 2p (p is an integer of 1 or more) times rotational symmetry. For example, even if the cross-sectional shape of the adjustment light beam IL is rotationally symmetric twice, adjustment in either the X-axis direction or the Y-axis direction is possible. Even if the adjustment is made in one direction, if the center of the beam cross section of the projection light is made incident on the oscillation axis of the micro mirror 2 in the scanning module 1, the projection light is reflected by the micro mirror 2. The light always enters the same position on the surface, and the one-dimensional scanning of the reflected light is not affected by the surface shape of the micromirror 2.

  Further, according to the present embodiment, the light receiving device 25 receives the adjustment light beam IL that has passed through the outside of the micromirror 2 and outputs an electrical signal corresponding to the amount of light received. Based on the electrical signal, the displacement of the center of the micromirror 2 relative to the center of the cross section of the adjustment light beam IL is detected.

  The light receiving surface of the light receiving device 25 is divided into four regions that are rotationally symmetric about the center of the cross section of the adjustment light beam IL. The difference in the amount of light received in each of the divided areas represents the displacement of the center of the micromirror 2 with respect to the center of the cross section of the adjustment light beam IL. Therefore, the displacement of the center of the micromirror 2 in at least one direction with respect to the center of the cross section of the adjustment light beam IL can be detected from the difference in the amount of light received in each divided region. The displacement detection device 26 detects the displacement of the center of the micromirror 2 with respect to the center of the cross section of the adjustment light beam IL according to the difference in the amount of light received in each divided area. By doing so, it becomes possible to detect the displacement of the center of the micromirror 2 having two XY orthogonal axes with respect to the cross-sectional center of the adjustment light beam IL.

  The number of divisions of the photodiodes on the light receiving surface of the light receiving device 25 is not limited to four, but is 2n (n is an integer of 2 or more) regions that are rotationally symmetric about the center of the cross section of the adjustment light beam IL. It only needs to be divided.

  Instead of the light receiving device 25, photoelectric sensors such as 2n photodiodes whose mutual light receiving surfaces are arranged rotationally symmetrical by 2n (n is an integer of 1 or more) about the center of the cross section of the adjustment light beam IL. A conversion means may be used. The difference in the amount of light received by each photoelectric conversion means represents the displacement of the center of the micromirror with respect to the center of the cross section of the adjustment light beam IL. In this case, an electric signal corresponding to the amount of light received by each photoelectric conversion means is input to the displacement detection device 26. The displacement detection device 26 detects the displacement of the center of the micromirror 2 with respect to the center of the cross section of the adjustment light beam IL based on the difference in the amount of light received by each photoelectric conversion means. This also makes it possible to make the center of the micromirror 2 in at least one direction coincide with the center of the cross section of the adjustment light beam IL.

  The light receiving surface of the light receiving device 25 receives an adjustment light beam IL that has passed through the outside of the micromirror 2 and outputs an image data signal corresponding to the light reception result, such as a CCD (charge coupled device). May be provided. This image data signal is a signal corresponding to the image of the micromirror by the adjustment light beam IL. In this case, an image data signal output from the image sensor is sent to the displacement detection device 26. The displacement detection device 26 performs image processing on the image data signal to detect the XY displacement of the center of the micromirror with respect to the center of the cross section of the adjustment light beam IL. This also makes it possible to make the center of the micromirror 2 in at least one direction coincide with the center of the cross section of the adjustment light beam IL. The light receiving surface of the light receiving device 25 is provided with a two-dimensional PSD (Position Sensitive Detector) element that receives the adjustment light beam IL that has passed through the outside of the micromirror 2 and outputs an electrical signal corresponding to the light reception result. It may be done. This PSD element is, for example, an element in which a resistance layer is provided on the surface of a photodiode.

  In the present embodiment, four micrometers MMX1, MMX2, MMY1, and MMY2 are used as the XY position of the scanning module 1, but a piezoelectric element may be used instead. . That is, a piezoelectric element is installed in place of the micrometers MMX1, MMX2, MMY1, and MMY2, and these are driven by voltage to press the scanning module 1 on the casing 50, whereby the position of the scanning module 1 on the casing 50 is determined. May be adjusted. Even in this manner, the position of the micromirror 2 can be finely adjusted. In addition, if two piezoelectric elements having opposite directions of pressing the micromirror 2 are provided to face each other, the position of the micromirror 2 can be changed from the + side and the − side as in the present embodiment. Adjustment is possible.

  In this embodiment, the micrometers MMX1, MMX2, MMY1, and MMY2 are driven by the operator's operation to adjust the position of the scanning module 1, but the XY displacement of the scanning module 1 detected by the displacement detection device 26 is adjusted. Based on this, the micrometers MMX1, MMX2, MMY1, and MMY2 may be driven to automatically adjust the XY position of the scanning module 1.

  In the present embodiment, the pair of actuators for adjusting the displacement of each axis is arranged in a line, but the actuators may be arranged in two lines in the X-axis direction or the Y-axis direction. In this way, it is possible to adjust the rotational deviation around the Z axis of the scanning module 1.

  Further, according to the method of manufacturing the optical scanning device according to the present embodiment, the housing 50 is positioned at a predetermined position, and the scanning module 1 is placed on the housing 50. The micromirror 2 included in the scanning module 1 is irradiated with the adjustment light beam IL having a substantially circular cross-sectional shape in which the beam diameter is larger than the diameter of the reflection surface of the micromirror 2. Next, based on the adjustment light beam IL that has passed through the outside of the micromirror 2, a displacement of the center of the micromirror 2 with respect to the beam cross-sectional center of the adjustment light beam IL is detected. Further, the position of the scanning module 1 on the housing 50 is adjusted based on the detected displacement. As a result of this adjustment, it is easy to make the center of the micromirror 2 coincide with the center of the cross section of the designed light beam.

  In addition, according to the manufacturing method according to the present embodiment, after the position of the scanning module 1 on the housing 50 is adjusted, the scanning module 1 is fixed to the housing 50, so The scanning module 1 can be fixed to the housing 50 in a state where the center of the mirror 2 is matched.

  Further, according to the scanning module 1 according to the present embodiment, the scanner 9 including the micromirror 2, the pedestal 5, and the substrate 6 have a structure that allows the adjustment light beam IL to pass from the outside of the micromirror 2. The adjustment light beam IL that has passed through the outside of the micromirror 2 can be directly received by the light receiving device 25 of the adjustment device 200. Therefore, the scanning module 1 is suitable for detecting the displacement of the center of the micromirror 2 with respect to the center of the cross section of the adjustment light beam IL.

  Further, according to the optical scanning device according to the present embodiment, the adjustment light beam IL that has passed through the outside of the micromirror 2 held by the frame portion 3 via the support portion 4 is converted into the fixing bracket 51, the housing 50, and Since the stage ST further passes, the adjustment light beam IL can be received by the light receiving device 25 of the adjustment device 200 as it is. Therefore, the retinal scanning display device 100 is suitable for detecting the displacement of the center of the micromirror 2 with respect to the center of the cross section of the adjustment light beam IL.

  The scanning module 1 according to the present invention is not limited to the retinal scanning display device 100, but also a projection-type optical scanning display device that projects scanning light on a projection screen or a building wall, projector, laser printer, laser lithography. Of course, the present invention can be applied to other apparatuses such as apparatuses, facsimiles, copying machines, image scanners, and bar code readers.

It is a schematic diagram which shows schematic structure of the retinal scanning display apparatus using the scanning module adjusted with the adjustment apparatus which concerns on one Embodiment of this invention. It is a disassembled perspective view which shows the structure of a scanning module. It is a figure which shows the structure of the adjustment apparatus which concerns on one Embodiment of this invention. 4 is a flowchart illustrating a method for manufacturing an optical scanning device according to an embodiment of the present invention. It is a figure explaining a manufacturing process (the 1). It is a figure explaining a manufacturing process (the 2). It is a figure explaining a manufacturing process (the 3). FIG. 8A and FIG. 8B are diagrams for explaining the relationship between the adjustment light beam that has passed the outside of the micromirror and the displacement of the micromirror.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Scan module 2 Micro mirror 3 Frame part 4 Support part 5 Base 6 Substrate 7 Beam part 8 Step part 9 Scanner 10 Light source part 11 Optical fiber 12 Collimating optical system 13 First relay optical system 14 Galvano mirror 15 Second relay optical System 16 Horizontal scanning synchronization circuit 17 Photo sensor 18 Vertical scanning synchronization circuit 21 LD control circuit 22 Laser light irradiation device 23 Light emitting diode 24 Collimator lens 25 Light receiving device 26 Displacement detection device 27 Monitor 50 Housing 51 Fixing bracket 100 Retina scanning display device 200 Adjustment device E Eyeball F Retina IL Adjustment light beam MMX1, MMX2, MMY2, MMY3 Micrometer ST Stage

Claims (14)

A scanning module including a micromirror that scans a light beam and configured so that the shape of the micromirror is approximately rotationally symmetric about 2 m (m is an integer of 2 or more) with respect to the central axis of the cross section. An adjusting device that adjusts an attachment position of the scanning module with respect to the housing when attaching,
A stage for positioning the casing at a predetermined position and mounting the scanning module on the casing;
An adjustment light beam whose effective diameter is determined to be at least larger than the diameter of the maximum circumscribed circle determined for the mirror shape is irradiated to the micromirror in the scanning module mounted on the housing. A light beam irradiation unit to
A displacement detection unit that detects a displacement of the center of the micromirror with respect to the beam cross-sectional center of the adjustment light beam based on the adjustment light beam that has passed outside the micromirror;
An adjustment device comprising: an adjustment unit that adjusts the position of the scanning module on the housing based on the displacement detected by the displacement detection unit. The displacement detector is
Photoelectric conversion means for receiving the adjustment light beam that has passed outside the micromirror and outputting an electrical signal corresponding to the amount of light received,
2. The adjustment device according to claim 1, wherein a displacement of a center of the micromirror with respect to a cross-sectional center of the adjustment light beam is detected based on an electric signal output from the photoelectric conversion means. The light receiving surface of the photoelectric conversion means is divided into 2n (n is an integer of 2 or more) regions that are rotationally symmetric about the center of the cross section of the adjustment light beam,
The adjustment device according to claim 2, wherein a displacement of a center of the micromirror with respect to a cross-sectional center of the adjustment light beam is detected according to a difference in received light amount of each of the divided areas.   The adjusting device according to claim 3, wherein the photoelectric conversion means has a light receiving surface divided into four regions that are rotationally symmetric. The displacement detector is
2n photoelectric conversion means arranged such that the mutual light receiving surfaces are rotationally symmetrical 2n (n is an integer of 1 or more) around the center of the cross section of the adjustment light beam,
3. The adjustment device according to claim 2, wherein a displacement of the center of the micromirror with respect to a center of a cross section of the adjustment light beam is detected based on a difference in received light amount of each photoelectric conversion means. The photoelectric conversion means includes
An image sensor that receives the adjustment light beam that has passed outside the micromirror and outputs an image data signal corresponding to the light reception result;
The adjustment device according to claim 2, wherein a displacement of a center of the micromirror with respect to a cross-sectional center of the adjustment light beam is detected based on an image data signal output from the imaging element.   The adjusting device according to claim 2, wherein the photoelectric conversion means is an element in which a resistance layer is provided on a surface of a photodiode. The adjustment unit has an actuator,
The displacement is given by driving the actuator to contact and press the scanning module on the casing, and the position of the scanning module on the casing is adjusted. The adjusting device according to one item. The adjustment unit is
The adjusting device according to claim 8, wherein two actuators whose directions of displacing the micromirrors are opposite to each other are provided to face each other.   The adjusting device according to claim 8, wherein the actuator is a piezoelectric element. A scanning module including a housing and a micromirror that scans a light beam, and the shape of the micromirror is approximately rotationally symmetric about 2m (m is an integer of 2 or more) with the central axis of the cross-section as a symmetry axis A method of manufacturing an optical scanning device comprising:
The micro-mirror in the scanning module placed on the housing positioned at a predetermined position has an effective beam diameter that is at least larger than the maximum circumscribed circle diameter determined for the mirror shape. An irradiation step of irradiating the adjustment light beam;
A displacement detection step of detecting a displacement of the center of the micromirror with respect to the beam cross-sectional center of the adjustment light beam based on the adjustment light beam that has passed outside the micromirror;
An adjustment step of adjusting the position of the scanning module on the housing using an actuator based on the displacement detected by the displacement detection step. After the adjustment process is performed,
The manufacturing method according to claim 11, further comprising a step of fixing the scanning module to the housing. A micromirror that is configured to be rotationally symmetric about 2 m (m is an integer of 2 or more) with respect to the central axis of the cross section, and whose shape scans the light beam by reflection of the cross section;
When an adjustment light beam having an effective beam diameter larger than at least the diameter of the maximum circumscribed circle defined for the mirror shape is incident on the micromirror, the adjustment light beam is passed through the micromirror. An optical scanning device comprising: a frame that can pass from the outside and that holds the micromirror in a swingable manner.   The apparatus further comprises a housing having a light passage portion on which the frame can be mounted and further allowing the adjustment light beam that has passed outside the micromirror held by the mounted frame to pass therethrough. 14. An optical scanning device according to 13.

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