JP5198561B2 - Optical scanning actuator and method of manufacturing optical scanning actuator - Google Patents

Description

  The present invention relates to an optical scanning actuator that scans a predetermined range with light emitted outward, and a method for manufacturing the optical scanning actuator.

  Conventionally, scanning laser radar devices, laser scanners, laser printers, laser markers, object monitoring devices, and the like are known as devices that use scanning devices such as laser light. Among these devices, one movable mirror is swung or rotated by a motor as an optical scanning actuator for use in a scanning laser radar device for preventing collision of a vehicle, and the light from the laser light source is movable. A technique for irradiating a mirror and scanning a predetermined range using the reflected light as exploration light is known (see, for example, Patent Document 1).

  FIG. 10 is a perspective view showing a configuration of a conventional optical scanning actuator. In the optical scanning actuator 31 shown in the figure, the base end portions of a pair of plate springs 34a and 34b arranged in parallel up and down are fixed to a fixing member 33 assembled to a base member 32 (the plate spring 34b is Not shown). The distal ends of the leaf springs 34a and 34b are fixed to a mirror holder 35 that holds a mirror 36 that reflects light emitted from a predetermined light source. The mirror holder 35 is movable according to the movement of the leaf springs 34a and 34b. In the mirror holder 35, a pair of coils 37a and 37b are disposed at symmetrical positions around the origin position of the leaf springs 34a and 34b.

  An arcuate yoke 38 is fastened to the base member 32 of the optical scanning actuator 31. The arc-shaped portion of the yoke 38 is composed of a lower portion 38a and an upper portion 38b that are parallel to each other, and the lower portion 38a passes through the opening surfaces of the coils 37a and 37b. A magnet 39 is fixed to the surface of the upper portion 38b that faces the lower portion 38a.

  The optical scanning actuator 31 having the above configuration forms a magnetic circuit in which the yoke 38 and the magnet 39 are closed. For this reason, the mirror holder 35 holding the coils 37 a and 37 b is driven by the electromagnetic force generated according to the current flowing through the coils 37 a and 37 b, and swings together with the mirror 36. Therefore, a predetermined range can be scanned with the light emitted from the mirror 36 to the outside.

International Publication No. 02/008818

  In the conventional optical scanning actuator 31 described above, the mirror 36 is positioned on the outer peripheral side with respect to the tips of the leaf springs 34a and 34b when viewed from the fixing member 33, and therefore the mirror when the mirror holder 35 swings. The amount of movement of 36 was large. For this reason, in order for the mirror 36 to always reflect the light from the fixed light source, the area of the mirror surface of the mirror 36 must be increased in accordance with the amount of movement of the mirror 36, and the light in a narrow space is required. In some cases, it is difficult to arrange the scanning actuator 31.

  The present invention has been made in view of the above, and an optical scanning actuator that can reduce the area of the mirror surface of a mirror that emits scanning light and can be disposed in a narrow space, and It is an object of the present invention to provide a method for manufacturing an optical scanning actuator.

  In order to solve the above-described problems and achieve the object, an optical scanning actuator according to the present invention is an optical scanning actuator that scans a predetermined range with light emitted toward the outside, and includes a leaf spring, A fixing member that fixes one end of the leaf spring, a movable member that holds the other end of the leaf spring, is movable according to the movement of the leaf spring, is attached to the movable member, and is projected from the outside. A mirror that reflects the light, a movable member, and a swinging means that swings the mirror, wherein the mirror surface of the mirror is fixed to the fixed member of the plate spring and the movable member It is located on the plane which passes between the free ends of the said leaf | plate spring hold | maintained by characterized by the above-mentioned.

  The optical scanning actuator according to the present invention is characterized in that, in the above invention, the mirror surface is orthogonal to the main surface of the leaf spring in an initial state where the leaf spring is not bent.

  In the optical scanning actuator according to the present invention, in the above invention, the mirror surface is an intersection of a tangential plane of the free end at a predetermined deflection position of the leaf spring and a main surface of the leaf spring in the initial state. It passes through the vicinity of the line or the line of intersection, and is perpendicular to the tangent plane.

  Further, in the optical scanning actuator according to the present invention, in the above invention, the swinging means has a couple of forces whose central axes are axes parallel to the main surface of the leaf spring and the mirror surface in the initial state. It adds to a movable member, It is characterized by the above-mentioned.

  In the optical scanning actuator according to the present invention as set forth in the invention described above, the swinging means is held by the magnet, a yoke to which the magnet is fixed, and a closed magnetic circuit together with the magnet, and the movable member. A coil through which the magnetic flux of the magnetic circuit penetrates, and an opening surface of the coil is parallel to a main surface of the leaf spring in the initial state and intersects with a plane including the mirror surface. .

  The optical scanning actuator according to the present invention includes a plurality of the leaf springs in the above invention, and in the initial state, the main surface of each leaf spring is located on the same plane and the longitudinal direction of each leaf spring is The magnet, the yoke, and the coil are arranged in parallel with each other in a substantially parallel state, and are located between any two adjacent leaf springs.

  In the optical scanning actuator according to the present invention, the width of the mirror surface along the swing direction in which the movable member and the mirror swing is the width of the movable member along the swing direction. It is characterized by being less than the width.

  An optical scanning actuator manufacturing method according to the present invention is an optical scanning actuator manufacturing method for manufacturing the optical scanning actuator according to the invention, wherein a plurality of candidate positions are set as the mirror installation position candidates. And the amount of movement of the mirror from the initial state according to the amount of deflection of the leaf spring when the mirror is arranged at each of the set candidate positions, and the amount of movement is minimized. The method includes a step of setting the candidate position as the installation position of the mirror.

  According to the present invention, a leaf spring, a fixing member that fixes one end of the leaf spring, a movable member that holds the other end of the leaf spring and is movable according to the movement of the leaf spring, and attached to the movable member A mirror that reflects the light projected from the outside, a movable member and a rocking means that rocks the mirror, and the mirror surface of the mirror is fixed to the fixed end of the leaf spring and the movable member fixed by the fixed member Therefore, the movement amount in the swinging direction in which the mirror swings can be reduced. Therefore, the area of the mirror surface of the mirror can be reduced, and the mirror can be arranged in a narrow space.

FIG. 1 is a block diagram showing a configuration of an object detection apparatus including an optical scanning actuator according to an embodiment of the present invention. FIG. 2 is a perspective view showing a configuration of an optical scanning actuator according to an embodiment of the present invention. FIG. 3 is a diagram in which a part of the configuration of the object detection apparatus is added to the partial cross-sectional view along the line AA in FIG. FIG. 4 is a diagram for explaining the installation positions of the mirrors provided in the optical scanning actuator according to the embodiment of the present invention. 5 is a cross-sectional view taken along the line CC of FIG. FIG. 6 is a diagram illustrating a driving mode of the optical scanning actuator according to the embodiment of the present invention. FIG. 7 is a diagram schematically showing an outline of the process of determining the mirror installation position in the method of manufacturing an optical scanning actuator according to one embodiment of the present invention. FIG. 8 is a diagram showing the amount of movement of the rotation axis of the mirror. FIG. 9 is a diagram illustrating the relationship between the deflection of the leaf spring and the amount of movement. FIG. 10 is a perspective view showing a configuration of a conventional optical scanning actuator.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. The drawings are schematic, and when the same object is shown in different drawings, the dimensions, scales, and the like may be different.

  FIG. 1 is a block diagram illustrating a configuration of an object detection apparatus that includes an optical scanning actuator according to an embodiment of the present invention and detects an object using light emitted from the optical scanning actuator. The object detection apparatus 100 shown in the figure emits light toward the outside, and the optical scanning actuator 1 that scans a predetermined range with the emitted light, and the projection that irradiates the optical scanning actuator 1 with light. Control of the light unit 2, the position detection unit 3 that detects the position of a predetermined portion of the optical scanning actuator 1, the light receiving unit 4 that receives the reflected light of the light emitted from the optical scanning actuator 1, and the control of the object detection device 100 The control part 5 which performs is provided. The light projecting unit 2 includes a laser diode and irradiates the optical scanning actuator 1 with laser light. The light receiving unit 4 includes a photodiode that receives laser light.

  FIG. 2 is a perspective view showing the configuration of the optical scanning actuator 1 according to the present embodiment. FIG. 3 is a diagram illustrating a configuration of a main part of the optical scanning actuator 1, and is a diagram obtained by adding a part of the configuration of the object detection device 100 to the AA line partial cross-sectional view of FIG. The optical scanning actuator 1 includes two plate springs 11 and 12 having a thin plate shape, a fixing member 13 fixed to a predetermined place and fixing one end of the plate springs 11 and 12, and the plate springs 11 and 12. A movable member 14 that can move according to the movement of the leaf springs 11 and 12, a mirror 15 that is attached to the movable member 14 and reflects the laser light emitted by the light projecting unit 2, and 2 The magnets 16 and 17, the magnets 16 and 17 are fixed, the yoke 18 that forms a closed magnetic circuit together with the magnets 16 and 17, and the movable member 14 is held, and the magnets 16 and 17 are positioned in the vicinity of the magnets 16 and 17 and the yoke 18. And a coil 19 to be provided.

  The leaf springs 11 and 12 have the same shape, and their main surfaces are located on the same plane in the initial state where the leaf springs are not bent (the state shown in FIG. 2). In addition, the longitudinal directions of the leaf springs 11 and 12 in the initial state are parallel to each other. As shown in FIG. 3, the fixed end 11 a of the leaf spring 11 is a boundary between a portion where the leaf spring 11 is held by the fixing member 13 and a portion where the leaf spring 11 is not held. On the other hand, the free end 11b of the leaf spring 11 is a boundary between a portion where the leaf spring 11 is held by the movable member 14 and a portion where the leaf spring 11 is not held. The fixed end 12a and the free end 12b of the leaf spring 12 are at the same positions as the fixed end 11a and the free end 11b of the leaf spring 11, respectively.

  Of the end portions of the leaf springs 11 and 12, the end portions held by the fixing member 13 are provided with electrode terminal portions 111 and 121 that protrude in the opposite direction to the direction in which the leaf springs 11 and 12 extend. ing. Lead wires for electrically connecting the leaf springs 11 and 12 and the controller 5 are attached to the electrode terminal portions 111 and 121, respectively. On the other hand, the other end of the lead wire whose one end is connected to the winding end of the coil 19 is connected in the vicinity of the end fixed to the movable member 14 among the ends of the leaf springs 11 and 12. For this reason, the control unit 5 and the coil 19 are electrically connected via the leaf springs 11 and 12. Thus, by making the leaf springs 11 and 12 function as substitutes for the lead wires, the coil energization circuit can be simplified.

  The leaf springs 11 and 12 are made of a thin leaf spring material such as beryllium copper, phosphor bronze, or stainless steel, and are formed by stamping or press forming by pressing.

  The movable member 14 has a substantially columnar shape orthogonal to the longitudinal direction of the leaf springs 11 and 12 in the initial state of the leaf springs 11 and 12, and is a plate that holds the distal end side from the free ends 11b and 12b of the leaf springs 11 and 12, respectively. A spring holding portion 141, a mirror mounting portion 142 that is formed in a substantially column shape extending from the upper end of the leaf spring holding portion 141 to the fixing member 13 side perpendicular to the leaf spring holding portion 141, and the mirror 15 is attached to the upper surface, and a leaf spring holding In the state in which the coil 19 is sandwiched by the two columnar portions, extending from the substantially central portion of the portion 141 to the fixing member 13 side along the longitudinal direction in the initial state of the leaf springs 11 and 12. And a coil holding part 143 for holding.

  The fixed member 13 and the movable member 14 are formed by injection molding an engineering plastic such as a liquid crystal polymer (LCP) or polyphenylene sulfide (PPS) filled with a lightweight and highly rigid glass fiber. When the fixed member 13 and the movable member 14 are formed, the leaf springs 11 and 12 may be integrally formed as an insert material.

  In the mirror 15, the width of the mirror surface along the swing direction in which the movable member 14 and the mirror 15 swing is equal to the width along the swing direction of the movable member 14. More generally, the width of the mirror surface in the swing direction may be equal to or less than the width of the movable member in the swing direction. The mirror 15 is realized using a light metal such as glass, synthetic resin, or aluminum, and has a mirror surface that is formed smoothly by aluminum vapor deposition or the like. You may provide the protective layer which consists of thin films, such as a silicon dioxide, with respect to this mirror surface.

FIG. 4 is a diagram illustrating the installation position of the mirror 15 and is a diagram illustrating the positional relationship between the leaf spring 11 and the mirror 15 when viewed from the direction of arrow B in FIG. Hereinafter, the leaf spring 11 and the leaf spring 12 are assumed to swing in substantially the same manner. In FIG. 4, the leaf springs 11 and 12 are each bent at a predetermined deflection angle θ ₀ (0 ° <θ ₀ <90 °). The “deflection angle” here refers to the plane P0 that passes through the main surface in the initial state of the leaf springs 11 and 12, the tangential plane of the free end 11b of the leaf spring 11 (the plane P1 in the case of FIG. 4). It is an angle formed by. In the present embodiment, the rotation axis Q that passes through the mirror surface of the mirror 15 and becomes the rotation center at the time of swinging is formed between the plane P0 and the tangential plane P1 of the free end 11b of the leaf spring 11 at the deflection angle θ ₀ . The position coincides with the intersection line. The value of the deflection angle θ ₀ that determines the installation position of the mirror 15 can be arbitrarily set. For example, it can be a value when the leaf springs 11 and 12 are most bent.

  5 is a cross-sectional view taken along the line CC of FIG. The yoke 18 is made of a soft magnetic material such as pure iron and is a block having a substantially E-shaped uniform cross section, and the portion corresponding to the central horizontal line among the three E-shaped horizontal lines is the hollow part of the coil 19. It penetrates. In addition, flat magnets 16 and 17 are fixed to the inner peripheral side of portions corresponding to the two upper and lower horizontal lines among the three E-shaped horizontal lines. The yoke 18 is fixed to the fixing member 13. The fixed position of the yoke 18 is a position where when the movable member 14 swings, the yoke 18 can pass through the recess 14 a surrounded by the leaf spring holding portion 141 and the coil holding portion 143 of the movable member 14. Note that a yoke having a substantially B-shaped closed cross section may be configured by attaching a flat soft magnetic material to a portion of the yoke 18 having an open substantially E-shaped cross section.

  The coil 19 is held by the coil holding part 143 of the movable member 14. In the initial state of the leaf springs 11 and 12, the opening surface of the coil 19 is parallel to the main surface of the leaf springs 11 and 12. The opening surface of the coil 19 intersects with a plane including the mirror surface of the mirror 15. As described above, a portion of the yoke 18 corresponding to the horizontal line at the center of the E shape passes through the hollow portion of the coil 19. Note that the coil 19 may be added as an insert material when the fixed member 13 and the movable member 14 are formed.

  The operation of the optical scanning actuator 1 having the above configuration will be described. 2, 3, and 5, when the control unit 5 supplies a drive current to the coil 19, the coil 19 is parallel to the main surfaces of the leaf springs 11 and 12 and the mirror surface of the mirror 15. A couple (size 2F) is generated with the axis passing through the center of the coil 19 (axis O in FIG. 5) as the central axis, and acts on the movable member 14 as a driving force for driving the movable member 14 and the mirror 15. . In this sense, the magnets 16 and 17, the yoke 18, and the coil 19 constitute swinging means that swings the movable member 14 and the mirror 15 based on the drive current sent from the control unit 5.

  FIG. 6 is a diagram showing a driving mode of the optical scanning actuator 1 viewed from the direction of arrow B in FIG. When receiving a driving force from the coil 19, the movable member 14 starts swinging together with the leaf springs 11 and 12 in the vertical direction of FIG. When the light projecting unit 2 irradiates the oscillating mirror 15 with laser light, the mirror 15 reflects the laser light. The optical scanning actuator 1 scans a predetermined range with the reflected light.

  While the movable member 14 and the mirror 15 are oscillating, the position detection unit 3 detects the position of a predetermined portion of the leaf spring 11, the movable member 14 or the mirror 15 and outputs it to the control unit 5. The control unit 5 controls the drive current that flows through the coil 19 by using the position information of the leaf spring 11, the movable member 14, or the mirror 15 sent from the position detection unit 3.

  In the optical scanning actuator 1, the position of the rotation axis Q of the mirror 15 hardly moves due to the swing of the mirror 15. For this reason, even if it does not enlarge the area of the mirror surface of the mirror 15 like the prior art of the patent document 1 mentioned above, the light with which the light projection part 2 irradiates can be made to reach a mirror surface reliably. Therefore, the width of the mirror 15 in the swing direction can be reduced, and the width of the fixed member 13 and the movable member 14 in the swing direction can be reduced accordingly. As a result, the entire optical scanning actuator 1 can be downsized and installed in a narrow space.

By the way, the movable member 14 and the mirror 15 do not swing with each part drawing a complete arc. For this reason, the position of the rotation axis Q of the mirror 15 slightly changes with the magnitude of the deflection angle θ ₀ .

FIG. 7 is a diagram showing an outline of the process of determining the installation position of the mirror 15 in the method for manufacturing an optical scanning actuator according to one embodiment of the present invention. When determining the installation position of the mirror 15, the plurality of candidate positions (four candidate positions 15a~15d in the case shown in FIG. 7), gradually increases up to the deflection angle theta reaches a predetermined deflection angle theta ₀ The amount of movement of the rotation axis of the mirror 15 from the initial state at this time is obtained, and the candidate position where the amount of movement is minimized is set as the installation position of the mirror 15.

FIG. 8 is a diagram illustrating a specific example of the amount of movement of the rotation axis of the mirror 15 when the mirror 15 is installed at the candidate position 15a. In FIG. 8, the rotation axis of the mirror 15 when the leaf springs 11 and 12 are in the initial state is represented by Qa, while the leaf spring 11 and 12 is deflected at a certain deflection angle θ (≦ θ ₀ ). The rotation axis is Qa ′, and the amount of movement from the rotation axis Qa to the rotation axis Qa ′ is ha. In FIG. 8, the tangent plane of the free end 11b of the leaf spring 11 at the deflection angle θ is P2 (the tangent plane P2 when θ = θ ₀ is nothing but the tangent plane P1).

FIG. 9 is a diagram illustrating the relationship between the deflection ν of the leaf springs 11 and 12 and the amount of movement h. In FIG. 9, the amount of deflection of the free ends 11b and 12b when deflected at the deflection angle θ ₀ is ν _max . The four straight lines La to Ld shown in FIG. 9 correspond to the case where the mirror 15 is disposed at each of the candidate positions 15a to 15d. Of the four straight lines La to Ld, the straight line Lc has the smallest movement amount h with respect to the same deflection ν. Therefore, in the case shown in FIG. 9, the candidate position 15 c is the installation position of the mirror 15.

  By the way, the rotation shaft Q shown in FIG. 4 is most preferable as the installation position. However, since only a finite number of candidate positions can actually be examined, the rotation axis of the mirror 15 at the candidate position does not always coincide with the rotation axis Q. Further, if the rotation axis of the mirror 15 at the candidate position is in the vicinity of the rotation axis Q, the movement amount of the rotation shaft is minute compared to the movement amount when the tip portions of the leaf springs 11 and 12 are swung. For this reason, even if the rotation axis of the mirror 15 at the candidate position does not coincide with the rotation axis Q, there is no practical problem.

  In addition, when calculating | requiring the relationship shown in FIG. 9, you may obtain | require by actual measurement and may obtain | require by the simulation using a computer.

  In this way, since the mirror is installed at a position where the amount of movement of the rotation axis of the mirror 15 corresponding to the amount of deflection from the initial state of the leaf springs 11 and 12 is minimized, the movement of the mirror during swinging is minimized. can do.

  According to the embodiment of the present invention described above, the leaf spring, the fixing member that fixes one end portion of the leaf spring, and the other end portion of the leaf spring are held and movable according to the movement of the leaf spring. A movable member, a mirror attached to the movable member and reflecting light projected from the outside, and a swinging means for swinging the movable member and the mirror are provided, and the mirror surface of the mirror is fixed by the fixed member Since it is located on a plane passing between the fixed end of the leaf spring and the free end of the leaf spring held by the movable member, the amount of movement in the swinging direction in which the mirror swings can be reduced. Therefore, the area of the mirror surface of the mirror can be reduced, and the mirror can be arranged in a narrow space.

  The best mode for carrying out the present invention has been described so far, but the present invention should not be limited only by the above-described embodiment. For example, in the present invention, the position where the mirror is installed need not necessarily be above the leaf spring.

  In the present invention, the mirror surface of the mirror may face the fixed end side of the leaf spring.

  In the present invention, the leaf spring may have a shape whose width gradually decreases from the fixed end held by the fixed member toward the free end held by the movable member.

  The number of leaf springs applied in the present invention is not limited to two, and may be one or three or more.

  In the present invention, the coil and the control unit may be electrically connected without using a leaf spring.

  INDUSTRIAL APPLICABILITY The present invention is suitable for irradiating a laser beam to the outside in a scanning laser radar device, a laser scanner, a laser printer, a laser marker, an object monitoring device, etc., and scanning a predetermined range with the irradiated laser beam. is there.

DESCRIPTION OF SYMBOLS 1, 31 Actuator for light scanning 2 Light projection part 3 Position detection part 4 Light receiving part 5 Control part 11a, 12a Fixed end 11b, 12b Free end 11, 12, 34a, 34b Leaf spring 13, 33 Fixed member 14 Movable member 14a Recessed part 15, 36 Mirror 15a, 15b, 15c, 15d Candidate position 16, 17, 39 Magnet 18, 38 Yoke 19, 37a, 37b Coil 32 Base member 35 Mirror holder 38a Lower part 38b Upper part 100 Object detection device 111, 121 Electrode Terminal part 141 Leaf spring holding part 142 Mirror mounting part 143 Coil holding part

Claims (8)

An optical scanning actuator that scans a predetermined range with light emitted toward the outside,
Leaf springs,
A fixing member for fixing one end of the leaf spring;
A movable member that holds the other end of the leaf spring and is movable according to the movement of the leaf spring;
A mirror attached to the movable member and reflecting light projected from the outside;
Rocking means for rocking the movable member and the mirror;
With
The mirror surface of the mirror is located on a plane passing between a fixed end of the leaf spring fixed by the fixing member and a free end of the leaf spring held by the movable member. Actuator for optical scanning. The mirror surface is
2. The optical scanning actuator according to claim 1, wherein the plate spring is orthogonal to a main surface of the plate spring in an initial state where the plate spring is not bent. The mirror surface is
Passing through or near the intersection of the tangential plane of the free end at a predetermined deflection position of the leaf spring and the main surface of the leaf spring in the initial state, and perpendicular to the tangential plane The optical scanning actuator according to claim 2. The swinging means is
4. The optical scanning actuator according to claim 2, wherein a couple of forces having a central axis parallel to the principal surface of the leaf spring and the mirror surface in the initial state is applied to the movable member. 5. The swinging means is
A magnet,
A yoke on which the magnet is fixed and forms a closed magnetic circuit with the magnet;
A coil held by the movable member and through which the magnetic flux of the magnetic circuit penetrates;
With
The opening surface of the coil is
5. The optical scanning actuator according to claim 2, wherein the actuator for optical scanning is parallel to a main surface of the leaf spring in the initial state and intersects with a plane including the mirror surface. A plurality of the leaf springs, and in the initial state, the main surfaces of the leaf springs are located on the same plane and the longitudinal directions of the leaf springs are arranged in parallel with each other in a substantially parallel state;
6. The optical scanning actuator according to claim 5, wherein the magnet, the yoke, and the coil are positioned between any two adjacent leaf springs.   The width of the mirror surface along the swinging direction in which the movable member and the mirror swing is less than or equal to the width of the movable member along the swinging direction. The optical scanning actuator according to claim 1. It is a manufacturing method of the optical scanning actuator which manufactures the optical scanning actuator as described in any one of Claims 1-7,
A plurality of candidate positions are set as candidates for the installation position of the mirror, and the mirror from the initial state according to the deflection amount of the leaf spring when the mirror is arranged at each of the plurality of set candidate positions. A method of manufacturing an optical scanning actuator, comprising a step of obtaining a movement amount and setting a candidate position where the movement amount is minimum as the installation position of the mirror.

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