JP2017181956A - Optical deflector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique that allows for identifying a state of a movable unit of an optical deflector configured to swing the movable unit by causing a peripheral edge of the movable unit to roll on a reference surface.SOLUTION: An optical deflector disclosed herein comprises: a base unit having a reference surface; a movable unit provided with a reflective section that reflects light and at least two transmissive sections that transmit light and supported by the base unit in such a way that the movable unit can swing by rolling a peripheral edge thereof on the reference surface; a drive unit configured to drive the movable unit to swing; a detection unit configured to detect a pattern of diffraction light diffracted by the at least two transmissive sections; and a processing unit configured to identify a state of the movable unit based on the pattern of the diffraction light.SELECTED DRAWING: Figure 1

Description

  The present specification relates to an optical deflector.

  Patent Document 1 discloses an optical deflector. This optical deflector is a movable part having a base part having a reference surface and a reflection part for reflecting light, the movable part supported by the base part so as to be rotatable while rolling the periphery on the reference surface, and the movable part. A drive device that rotates is provided. In this optical deflector, the reflection angle can be adjusted to an arbitrary azimuth angle by rotationally driving the movable portion by the driving device. Moreover, in this optical deflector, since the periphery of the movable part is elliptical, a different angle of attack is realized with respect to the same azimuth each time the movable part rotates once. According to this optical deflector, it is possible to scan in two directions, the longitude direction and the latitude direction. In addition, the azimuth angle as used in this specification means the angle made with a reference line in the reference plane of the base. As used herein, the longitude direction refers to the direction in which the azimuth angle increases or decreases. In addition, the angle of attack in this specification refers to an angle formed with the reference plane of the base. As used herein, the latitude direction refers to the direction in which the angle of attack increases or decreases.

JP 2013-246382 A

  In the technique of Patent Document 1, when the movable unit is rotated by the driving device, the state of the movable unit, for example, the angle of attack of the reflecting unit, the azimuth angle of the reflecting unit, the number of rotations of the moving unit, and the like can be specified. Can not. In an optical deflector that rotates a movable part while rolling the periphery of the movable part on a reference plane, a technique capable of specifying the state of the movable part is expected.

  The present specification provides a technique for solving the above problems. The present specification provides a technique capable of specifying the state of a movable part in an optical deflector that rotates the movable part while rolling the periphery of the movable part on a reference plane.

  An optical deflector disclosed in the present specification is a movable part including a base part having a reference surface, a reflection part that reflects light, and at least two light-transmitting parts that transmit light, and a peripheral edge on the reference surface. Based on a movable part that is supported by a base so as to be rotatable while rolling, a driving device that rotationally drives the movable part, a detection device that detects a pattern of diffracted light diffracted by at least two light transmitting parts, and a pattern of diffracted light And a processing device for specifying the state of the movable part.

  In the above optical deflector, most of the incident light is reflected by the reflecting portion, and a part of the incident light is diffracted by at least two light transmitting portions, so that a diffracted light pattern is formed at the base. The pattern of this diffracted light changes depending on the state of the movable part. In the above optical deflector, the processing device specifies the state of the movable part based on the pattern of diffracted light. According to the above optical deflector, the state of the movable part can be specified in the optical deflector that rotates the movable part while rolling the periphery of the movable part on the reference plane.

  In the above optical deflector, the processing device specifies the shape of the 0th order light due to the interference of the diffracted light diffracted by the at least two light transmitting portions in the diffracted light pattern, and the angle of attack of the reflecting portion is determined from the shape of the 0th order light. Can be configured to identify.

  The zero-order light due to the interference of diffracted light diffracted by at least two light transmitting portions has the highest light intensity in the pattern of diffracted light, and the shape thereof can be easily specified. The shape of the zero-order light due to interference is uniquely determined by the position of the contact point between the periphery of the movable part and the reference surface in the movable part, and the angle of attack of the reflection part is also the contact between the periphery of the movable part and the reference surface. It is uniquely determined by the position of the point in the movable part. Therefore, the angle of attack of the reflecting portion can be specified by specifying the shape of the zero-order light due to interference.

  The optical deflector can be configured such that the processing device specifies the rotation angle of the 0th-order light in the diffracted light pattern and specifies the azimuth angle of the reflecting portion from the rotation angle of the 0th-order light.

  Although the shape of the 0th-order light due to interference is uniquely determined according to the angle of attack of the reflecting part, when the azimuth angle of the reflecting part is different, the rotation angle of the 0th-order light with respect to the base is different. The rotation angle of the zero-order light with respect to the base due to the interference is uniquely determined by the position of the contact point between the periphery of the movable part and the reference surface at the base. Further, the azimuth angle of the reflecting portion, that is, the azimuth angle of the contact point between the periphery of the movable portion and the reference surface is uniquely determined by the position of the contact point between the periphery of the movable portion and the reference surface at the base portion. According to the above optical deflector, by specifying the shape of the 0th-order light due to interference, it is possible to specify the angle of attack of the reflecting portion, and further by specifying the rotation angle of the 0th-order light due to interference, The azimuth angle of the reflection part can also be specified.

  In the optical deflector, the movable part is supported on the base by a support column that protrudes upward from the reference plane, and the processing device causes the diffracted light from at least one translucent part to be reflected by the support column in the pattern of diffracted light. Thus, the shape of the non-light-projecting area that is not projected can be specified, and the amount of displacement of the movable portion with respect to the support column can be specified from the shape of the non-light-projecting area.

  As described above, in the optical deflector in which the movable part is supported on the base by the support column, the movable part may rotate in a state of being displaced from the support column. If the movable part rotates in a state shifted from the support, the angle of attack and the azimuth angle of the reflecting part will be different from those assumed in the design. In the above optical deflector, the non-projection area that becomes the shadow of the support in the diffracted light pattern is specified, and the shift amount of the movable part with respect to the support is specified from the shape of the non-projection area. Thereby, for example, when the amount of displacement of the movable part with respect to the support column becomes large, the processing apparatus can be configured to output an abnormal signal.

  In the optical deflector, the processing device specifies the rotation angle of the non-projection area in the diffracted light pattern, and specifies the rotation speed of the movable part from the change over time of the rotation angle of the non-projection area. Can be configured.

  The non-light-projecting region that becomes the shadow of the support in the diffracted light pattern rotates once with respect to the base every time the movable portion rotates once with respect to the base. Therefore, by specifying the rotation angle of the non-projection area in the diffracted light pattern, the rotational speed of the movable part can be specified from the change with time of the rotation angle of the non-projection area.

  The above-described optical deflector can be configured such that the periphery of the movable part is elliptical.

  According to the above optical deflector, it is possible to scan in two directions of the longitude direction and the latitude direction.

  According to the technique disclosed in this specification, the state of the movable part can be specified in the optical deflector that rotates the movable part while rolling the periphery of the movable part on the reference plane.

It is a longitudinal cross-sectional view which shows the schematic structure of the optical deflector 2 which concerns on an Example. It is a top view of the movable part 6 of the optical deflector 2 which concerns on an Example. It is a top view of the base 4 of the optical deflector 2 which concerns on an Example. In the optical deflector 2 which concerns on an Example, it is a figure which shows the relationship between the azimuth angle (theta) of the contact point seen from the base 4, and the angle of attack (phi) of the reflective surface of the movable part 6. FIG. In the optical deflector 2 which concerns on an Example, it is a figure which shows the shift | offset | difference of the phase of the base 4 and the movable part 6 when the movable part 6 rotates 1 round. FIG. 6 is a diagram illustrating a principle in which a phase shift occurs between the azimuth angle θ of the contact point viewed from the base portion 4 and the phase angle α of the contact point viewed from the movable portion 6 in the optical deflector 2 according to the embodiment. It is a top view which shows the deformation | transformation form of the movable part 6 in the optical deflector 2 which concerns on an Example. It is a top view which shows another modification of the movable part 6 in the optical deflector 2 which concerns on an Example. It is sectional drawing which shows the diffraction of the light in the light transmission holes 24b and 24c in the optical deflector 2 which concerns on an Example. It is a figure which illustrates the shape of the 0th-order light by interference in the optical deflector 2 which concerns on an Example. It is a figure which shows the example of another arrangement | positioning of the light transmission holes 24b and 24c in the optical deflector 2 which concerns on an Example. It is a figure which shows the example of another arrangement | positioning of the light transmission holes 24b and 24c in the optical deflector 2 which concerns on an Example. It is a figure which shows the example of another arrangement | positioning of the light transmission holes 24b and 24c in the optical deflector 2 which concerns on an Example. It is a figure which shows the example of another arrangement | positioning of the light transmission holes 24b and 24c in the optical deflector 2 which concerns on an Example. It is a figure which shows the example of another arrangement | positioning of the light transmission holes 24b and 24c in the optical deflector 2 which concerns on an Example. It is a figure which shows the example of another arrangement | positioning of the light transmission holes 24b and 24c in the optical deflector 2 which concerns on an Example. It is a figure which shows the example of another arrangement | positioning of the light transmission holes 24b and 24c in the optical deflector 2 which concerns on an Example. It is a figure which shows the example of the pattern 40 of the diffracted light in the optical deflector 2 which concerns on an Example. It is a figure which shows another example of the pattern 40 of the diffracted light in the optical deflector 2 which concerns on an Example. It is a figure which shows another example of the pattern 40 of the diffracted light in the optical deflector 2 which concerns on an Example.

(Example)
FIG. 1 shows an optical deflector 2 of this embodiment. The optical deflector 2 includes a base portion 4, a movable portion 6, a drive device 8, a detection device 10, and a processing device 12.

  The base 4 includes a support substrate 14, a support layer 16, a detection substrate 18, a surface substrate 20, and support columns 22. The support substrate 14 is formed from, for example, a silicon wafer. A support layer 16 is bonded to the upper surface of the support substrate 14. The support layer 16 is formed from, for example, a silicon wafer. The support layer 16 is formed with a central hole 16a through which the support column 22 passes and an accommodation hole 16b in which the drive device 8 is accommodated. A detection substrate 18 is bonded to the upper surface of the support layer 16. The detection substrate 18 is formed from, for example, a silicon wafer. A central hole 18a through which the support column 22 passes is formed in the detection substrate 18. The detection substrate 18 is formed with a plurality of photodetectors 18b that each detect the light intensity. As shown in FIG. 3, the plurality of photodetectors 18 b are arranged side by side in the vertical direction and the horizontal direction on the detection substrate 18, and constitute a photodetector array. As shown in FIG. 1, the surface substrate 20 is bonded to the upper surface of the detection substrate 18. The surface substrate 20 is made of a transparent nonmagnetic material such as acrylic. Hereinafter, the upper surface of the front substrate 20 is also referred to as a reference plane P. Hereinafter, directions orthogonal to each other in the reference plane P are referred to as an X direction and a Y direction, and a direction orthogonal to the reference plane P is referred to as a Z direction. A central hole 20 a through which the support column 22 passes is formed in the surface substrate 20. The support column 22 is a rod-shaped member made of a magnetic material. The lower end of the column 22 is fixed to the support substrate 14. The support column 22 projects through the center hole 16 a of the support layer 16, the center hole 18 a of the detection substrate 18, and the center hole 20 a of the surface substrate 20 and protrudes to the upper surface side of the surface substrate 20. The support column 22 is formed in a shape in which the cross-sectional area decreases in the vicinity of the upper end in the vicinity of the upper end. Hereinafter, the upper end of the support column 22 is also referred to as a support point S.

  As shown in FIGS. 1 and 2, the movable portion 6 includes a reflecting plate 24 formed in an elliptical flat plate shape, and a columnar permanent magnet 26 fixed to the lower surface of the reflecting plate 24. Hereinafter, the major axis direction of the ellipse of the reflecting plate 24 is the pitch axis of the movable part 6, the minor axis direction of the ellipse of the reflecting plate 24 is the roll axis of the movable part 6, and the direction orthogonal to the reflecting plate 24 is the movable part 6. The yaw axis. The reflector 24 is made of a magnetic material. A reflection film 24 a that reflects incident light is formed on the upper surface of the reflection plate 24. The reflective film 24a is a deposited film such as Al. The surface of the reflective film 24a is also referred to as a reflective surface. As shown in FIG. 2, two light transmitting holes 24 b and 24 c are formed in the reflecting plate 24. The light transmitting holes 24b and 24c are through holes that penetrate the reflecting plate 24 from the surface of the reflecting film 24a to the back surface side. The light transmitting holes 24b and 24c may be filled with a transparent or translucent material, or may not be filled with anything. The light transmitting holes 24b and 24c are arranged side by side within a range smaller than the spot diameter of light irradiated to the optical deflector 2 when the reflector 24 is viewed in plan from the yaw axis direction. In the example shown in FIG. 2, the translucent holes 24 b and 24 c are permanent magnets, which will be described later, between one end (the end of B in FIG. 2) in the minor axis direction of the reflector 24 and the center of the reflector 24. It is arranged at a position close to the center of the reflector 24 within a range that does not overlap with 26. In the example shown in FIG. 2, the light transmitting holes 24 b and 24 c are symmetrical with respect to a straight line passing through one end portion (end portion of B in FIG. 2) in the minor axis direction of the reflecting plate 24 and the center of the reflecting plate 24. It is arranged in the position.

  The permanent magnet 26 is, for example, a cylindrical neodymium magnet. The permanent magnet 26 is arranged so that the center of the permanent magnet 26 and the center of the reflecting plate 24 coincide with each other when the movable part 6 is viewed in plan from the yaw axis direction. As shown in FIG. 1, the permanent magnet 26 is arranged so that the direction of the polarity of the magnetic force coincides with the yaw axis direction of the movable portion 6. The movable portion 6 is supported by the base portion 4 when the lower surface of the permanent magnet 26 contacts the support point S at the upper end of the support column 22. The movable portion 6 is attracted to the support point S at the upper end of the column 22 by the magnetic attractive force acting between the permanent magnet 26 and the column 22. The movable portion 6 is supported so as to be swingable with respect to a support point S at the upper end of the support column 22 with respect to three axes of a pitch axis, a roll axis, and a yaw axis.

  As shown in FIG. 3, the drive device 8 includes six electromagnets 28a, 28b, 28c, 28d, 28e, and 28f. The electromagnets 28 a, 28 b, 28 c, 28 d, 28 e, 28 f are all accommodated in the accommodation holes 16 b of the base 4. The electromagnets 28a, 28b, 28c, 28d, 28e, and 28f are arranged at positions that divide the circumference of a circle centered on the support point S of the support 22 into six equal parts when the base 4 is viewed in plan from the Z direction. Yes. The electromagnets 28 a, 28 b, 28 c, 28 d, 28 e and 28 f are arranged so that the direction of the polarity of the magnetic force coincides with the direction orthogonal to the reference plane P of the surface substrate 20. Generation of magnetic force by the electromagnets 28a, 28b, 28c, 28d, 28e, and 28f can be individually controlled.

  For example, when a magnetic force is generated in one electromagnet 28a of the driving device 8, a magnetic attractive force directed to the electromagnet 28a acts on the reflector 24, which is a magnetic body, and the movable portion 6 swings. Thereby, as shown in FIG. 1, the periphery of the reflecting plate 24 contacts the reference plane P in the vicinity of the electromagnet 28a. Next, when the generation of the magnetic force in the electromagnet 28a is stopped and the magnetic force is generated in the electromagnet 28b arranged next to the electromagnet 28a, the magnetic attraction force toward the electromagnet 28b acts on the reflecting plate 24, and the reflecting plate 24 The peripheral edge rotates around the yaw axis while rolling on the reference plane P, and the peripheral edge of the reflector 24 shifts to a state where it contacts the reference plane P in the vicinity of the electromagnet 28b. In this way, by sequentially switching the electromagnets 28a, 28b, 28c, 28d, 28e, and 28f that generate magnetic force, the reflector 24 continues to rotate around the yaw axis while rolling the periphery on the reference plane P.

  4 shows the azimuth angle θ (see FIG. 3) of the contact point when viewed from the base 4 when the reflector 24 is rotated around the yaw axis while rolling the periphery of the reflector 24 on the reference plane P. 24 shows the relationship of the angle of attack φ (see FIG. 1) of 24 reflecting surfaces. Here, the azimuth angle θ represents the rotation angle from the X axis in the reference plane P, and the angle of attack φ represents the tilt angle with respect to the XY plane (that is, the reference plane P). The reflecting plate 24 is formed in a shape in which the distance in the direction orthogonal to the yaw axis from the center to the periphery changes in accordance with the phase angle α (see FIG. 2). Here, the phase angle α indicates a rotation angle from the pitch axis in a plane orthogonal to the yaw axis. Accordingly, the phase angle α of the contact point viewed from the reflector 24 also changes in accordance with the change in the azimuth angle θ of the contact point viewed from the base portion 4, and the angle of attack φ of the reflection surface of the reflector 24 also changes accordingly. To do. The reflection angle of the optical deflector 2 is defined by the azimuth angle θ of the contact point viewed from the base 4 and the angle of attack φ of the reflection surface of the reflection plate 24.

  As shown in FIG. 5, in the optical deflector 2 of the present embodiment, the reference point (for example, one end in the major axis direction, that is, the end of A in FIG. 2) is in contact with the reference plane P. When the reflecting plate 24 is rotated once around the yaw axis from the state and the reference point comes into contact with the reference plane P again, the reflecting plate 24 is out of phase with the base 4 by a predetermined angle δ. This is due to the following reason.

  As shown in FIG. 6, the reflector 24 rotates around the yaw axis while rolling the peripheral edge on the reference plane P, and the azimuth angle θ of the contact point viewed from the base 4 changes by a minute angle dθ. If the phase angle α of the contact point viewed from the point of view changes by a minute angle dα, assuming that no slip occurs between the reflector 24 and the reference plane P, the following equation holds from the geometrical relationship.

  Therefore, if the amount of deviation of the angle between the azimuth angle θ of the contact point viewed from the base 4 and the phase angle α of the contact point viewed from the reflector 24 is a phase shift δ, the following relationship is established.

  Therefore, the phase shift δ that occurs while the azimuth angle θ of the contact point viewed from the base 4 increases by 2π is given by the following equation.

  Due to the above-described phase shift δ between the azimuth angle θ and the phase angle α, as shown in FIG. 4, every time the movable part 6 rotates once, the angle of attack φ is different with respect to the same azimuth angle θ. Is realized. Thereby, according to the optical deflector 2 of a present Example, the combination of arbitrary azimuth angles (theta) and angle of attack (phi) is realizable by rotating the movable part 6 repeatedly. According to the optical deflector 2 of the present embodiment, it is possible to scan in two directions, the longitude direction and the latitude direction.

  It should be noted that the shape of the reflecting plate 24 when viewed on a plane orthogonal to the yaw axis can be various shapes other than the elliptical shape as described above.

  For example, the reflector 24 can be circular. Alternatively, as shown in FIG. 7, the reflector 24 can be polygonal. Alternatively, as shown in FIG. 8, the reflecting plate 24 may be a Roule polygonal shape. Alternatively, although not shown, the reflector 24 can be shaped like a heart shape or a star shape.

  The detection apparatus 10 shown in FIG. 1 includes a plurality of photodetectors 18b on the detection substrate 18. Each photodetector 18b detects the light intensity and outputs it to the processing device 12.

  The processing device 12 specifies the pattern of diffracted light formed on the detection substrate 18 based on the detection signal from the photodetector 18b of the detection device 10. Hereinafter, a pattern of diffracted light formed on the detection substrate 18 in the optical deflector 2 will be described.

  FIG. 9 shows light diffraction at the two light transmitting holes 24b and 24c. When light is incident on the optical deflector 2, most of the incident light is reflected by the reflecting film 24a of the reflecting plate 24, and part of the incident light is diffracted by the light transmitting holes 24b and 24c. The diffracted light diffracted by the light transmitting holes 24 b and 24 c passes through the transparent surface substrate 20 and is projected onto the detection substrate 18.

And light-transmitting hole 24b, the distance 24c and d, the optical path difference of the incident light caused by the inclination angle β of the reflecting plate 24 with respect to the incident light and [Delta] X _1, the optical path of the diffracted light caused by the inclination angle γ with respect to the reflection plate 24 of the diffracted light When the difference between [Delta] X _2, the following relationship holds.

In the position where the sum of [Delta] X ₁ and [Delta] X ₂ (or difference) is an integer multiple of the wavelength λ of the incident light, the diffracted light is mutually reinforce. Therefore, on the detection substrate 18, a diffracted light pattern is formed in which the light intensity increases at a position where the following relationship is established.

  In particular, in the above formula, the case where m = 0 is referred to as zero-order light. In the diffracted light pattern on the detection substrate 18, the light intensity is the strongest at the position where the zero-order light is formed.

  The shape of the zero-order light in the pattern of diffracted light on the detection substrate 18 changes according to the phase angle α viewed from the reflector 24 at the contact point between the peripheral edge of the reflector 24 and the reference plane P.

  FIG. 10 shows an example of the shape of the zero-order light in the diffracted light pattern on the detection substrate 18. FIG. 10A shows a case where the contact point between the reflecting plate 24 and the reference plane P is the end of A in FIG. 2, that is, the phase angle α of the contact point viewed from the reflecting plate 24 is 0 °. ing. FIG. 10B shows the case where the contact point between the reflecting plate 24 and the reference plane P is the end of B in FIG. 2, that is, the phase angle α of the contact point viewed from the reflecting plate 24 is 90 °. ing. FIG. 10C shows a case where the contact point between the reflector 24 and the reference plane P is the end of C in FIG. 2, that is, the phase angle α of the contact point viewed from the reflector 24 is 180 °. ing. FIG. 10D shows a case where the contact point between the reflecting plate 24 and the reference plane P is the end of D in FIG. 2, that is, the phase angle α of the contact point viewed from the reflecting plate 24 is 270 °. ing. As shown in FIGS. 10A to 10D, the shape of the 0th-order light in the diffracted light pattern changes according to the phase angle α of the contact point viewed from the reflector 24. Therefore, the processing device 12 stores in advance the correspondence between the phase angle α of the contact point viewed from the reflecting plate 24 and the shape of the 0th-order light at that time, and the 0th-order light based on the detection signal from the detection device 10. By specifying the shape, the phase angle α of the contact point viewed from the reflecting plate 24 can be specified. Since the angle of attack φ of the reflector 24 is uniquely determined from the phase angle α of the contact point viewed from the reflector 24, the angle of attack φ of the reflector 24 is specified from the phase angle α of the contact point viewed from the reflector 24. can do.

  Note that the zero-order light in the above-described diffracted light pattern is detected in a state of rotating around the Z axis with respect to the base 4 in accordance with the azimuth angle θ of the contact point viewed from the base 4. Accordingly, the processing device 12 specifies the shape of the zero-order light and the rotation angle around the Z axis based on the detection signal from the detection device 10, so that the angle of attack φ of the reflector 24 and the base 4 It is possible to specify the azimuth angle θ of the contact point as seen. Depending on the shape of the reflector 24 and the arrangement of the light transmitting holes 24b and 24c, there may be cases where the 0th-order light has the same shape and rotation angle even though the angle of attack φ and azimuth angle θ of the reflector 24 are different. obtain. In this case, the angle of attack φ and the azimuth angle θ of the reflecting plate 24 are not uniquely determined from the shape of the zero-order light and the rotation angle. In such a case, for example, from the continuity of the shape of the previous zero-order light and the rotation angle (that is, the angle of attack φ and the azimuth angle θ of the immediately preceding reflector 24), the angle of attack φ of the reflector 24 is The correct attack angle φ and azimuth angle θ can be identified from the azimuth angle θ candidates. Alternatively, the light transmitting holes 24b and 24c are formed with respect to the support column 22 from the direction in which the non-light-projecting region 30 (see FIGS. 18 to 20) that is a shadow of the support column 22 when viewed from the light transmitting holes 24b and 24c described later. By specifying the direction in which the light is positioned, the angle of attack φ and the azimuth angle θ of the reflector 24 can be uniquely specified from the shape and rotation angle of the zero-order light and the positions of the light transmitting holes 24b and 24c.

  In addition, the arrangement | positioning of the light transmission holes 24b and 24c in the reflecting plate 24 can be various arrangements other than the above. For example, the light transmitting holes 24b and 24c may be arranged as shown in FIG. In the example shown in FIG. 11, the light transmitting holes 24 b and 24 c are arranged side by side on a straight line passing through one end part (the end part of B) in the minor axis direction of the reflecting plate 24 and the center of the reflecting plate 24. Further, it is arranged at a position close to the center of the reflector 24 within a range not overlapping the permanent magnet 26.

  Or you may arrange | position the translucent holes 24b and 24c, as shown in FIG. In the example shown in FIG. 12, the light transmitting holes 24 b and 24 c are within a range that does not overlap with the permanent magnet 26 between one end portion (the end portion of A) in the major axis direction of the reflecting plate 24 and the center of the reflecting plate 24. These are disposed at positions close to the center of the reflecting plate 24. In the example shown in FIG. 12, the translucent holes 24 b and 24 c are arranged at line-symmetrical positions with a straight line passing through one end (the end of A) in the major axis direction of the reflector 24 and the center of the reflector 24. Has been.

  Or you may arrange | position the translucent holes 24b and 24c, as shown in FIG. In the example shown in FIG. 13, the light transmitting holes 24 b and 24 c are arranged side by side on a straight line passing through one end (the end of A) in the major axis direction of the reflecting plate 24 and the center of the reflecting plate 24. It is arranged at a position close to the center of the reflector 24 within a range that does not overlap with the permanent magnet 26.

  Or you may arrange | position the translucent holes 24b and 24c, as shown in FIG. In the example shown in FIG. 14, the translucent hole 24 b is reflected within a range that does not overlap with the permanent magnet 26 between one end (the end of A) in the major axis direction of the reflector 24 and the center of the reflector 24. It is arranged at a position close to the center of the plate 24. The light transmitting hole 24c is close to the center of the reflecting plate 24 in a range that does not overlap the permanent magnet 26 between the other end portion (the end portion of C) in the major axis direction of the reflecting plate 24 and the center of the reflecting plate 24. Placed in position.

  Or you may arrange | position the translucent holes 24b and 24c, as shown in FIG. In the example shown in FIG. 15, the light transmitting hole 24 b is in a range that does not overlap the permanent magnet 26 between one end portion (end portion of B) in the minor axis direction of the reflecting plate 24 and the center of the reflecting plate 24. It is disposed at a position close to the center of the reflector 24. The light transmitting hole 24c is close to the center of the reflecting plate 24 in a range that does not overlap the permanent magnet 26 between the other end in the minor axis direction (the end of D) of the reflecting plate 24 and the center of the reflecting plate 24. It is arranged at the position to do.

  Or you may arrange | position the translucent holes 24b and 24c, as shown in FIG. In the example shown in FIG. 16, the light transmitting holes 24 b and 24 c are arranged side by side on a straight line passing through one end portion (end portion of B) in the minor axis direction of the reflecting plate 24 and the center of the reflecting plate 24. The reflector 24 is disposed at a position close to the periphery of the reflector 24.

  Or you may arrange | position the translucent holes 24b and 24c, as shown in FIG. In the example shown in FIG. 17, the light transmitting holes 24 b and 24 c are formed between the center of the reflecting plate 24 and the peripheral edge between one end (the end of A) in the major axis direction of the reflecting plate 24 and the center of the reflecting plate 24. It is arranged in the middle position. In the example shown in FIG. 17, the translucent holes 24 b and 24 c are arranged in line-symmetric positions with a straight line passing through one end (end of A) in the major axis direction of the reflector 24 and the center of the reflector 24. Has been.

  With respect to the pattern of diffracted light formed on the detection substrate 18, the state of the movable portion 6 can also be specified from features other than the zero-order light. As shown in FIG. 18, a concentric diffracted light pattern 40 is formed on the detection substrate 18 by interference, but a non-light-projecting region 30 that becomes a shadow of the support column 22 when viewed from the light transmitting holes 24b and 24c. Then, diffracted light is not projected. In such a non-light emitting region 30, the light intensity is substantially zero. As shown in FIGS. 18 and 19, the direction in which such a non-light-projecting region 30 is formed varies depending on the positions of the light transmitting holes 24 b and 24 c with respect to the column 22. Accordingly, the processing device 12 specifies the direction of the non-light-projecting region 30 from the diffracted light pattern 40 formed on the detection substrate 18, so that the light transmitting holes 24 b and 24 c are positioned with respect to the support column 22. Can be specified. In addition, the non-light emitting region 30 rotates once on the detection substrate 18 every time the reflecting plate 24 rotates once with respect to the base 4. Therefore, the processing device 12 can specify the number of rotations of the movable unit 6 relative to the base 4 by specifying the number of rotations of the non-light-projecting region 30. For example, the processing device 12 compares the switching frequency of the electromagnets 28a, 28b, 28c, 28d, 28e, and 28f of the drive device 8 with the rotational speed of the movable part 6 specified above, and there is a difference between the two. Alternatively, it may be determined that an abnormality has occurred in the optical deflector 2 and an abnormality signal may be output.

  In the optical deflector 2, the permanent magnet 26 of the movable portion 6 can slide with respect to the support point S of the column 22. Therefore, in the optical deflector 2, the center of the permanent magnet 26 of the movable part 6 may rotate with the support point S shifted. When such a deviation occurs, the pattern of diffracted light formed on the detection substrate 18 changes, and the shape of the non-light-projecting region 30 changes. Accordingly, the processing device 12 stores in advance the amount of deviation of the movable portion 6 with respect to the support point S and the shape of the non-light emitting area 30 when the amount of deviation occurs in association with each other on the detection substrate 18. By specifying the shape of the non-projection region 30 from the formed diffracted light pattern, it is possible to detect the amount of deviation of the movable portion 6 from the support point S. The processing device 12 determines that an abnormality has occurred in the optical deflector 2 and outputs an abnormality signal when the amount of deviation of the movable part 6 detected as described above from the support point S exceeds a predetermined value. You may comprise.

  As shown in FIGS. 14 and 15, when the translucent holes 24 b and 24 c are arranged at positions that sandwich the support 22 when the reflector 24 is viewed in plan from the yaw axis direction. As shown in FIG. 20, a non-light-projecting region 30 is formed in a range that becomes a shadow of the support column 22 when viewed from the light transmitting holes 24b and 24c. In this case, the diffracted light is projected from only one of the light transmitting holes 24b and 24c, and the diffracted light from the other of the light transmitting holes 24b and 24c is not projected to the non-light projecting region 30. Accordingly, in this case, the non-projection region 30 has less fluctuation due to the location of the light intensity compared to other locations where the diffracted light interferes. Even when such a non-light-projecting region 30 is formed, the rotational speed of the movable part 6 and the shift amount of the movable part 6 with respect to the support point S can be specified in the same manner as described above.

  In the various embodiments described above, if the diameters of the light transmitting holes 24b and 24c are too small, the diffracted light from the respective light transmitting holes 24b and 24c becomes weak and it is difficult to detect the pattern of the diffracted light on the detection substrate 18. It becomes. However, if the diameters of the light transmitting holes 24b and 24c are too large, direct light that linearly passes through the light transmitting holes 24b and 24c is projected onto the detection substrate 18, and the diffracted light on the detection substrate 18 is projected. The pattern cannot be detected. On the other hand, if the diameters of the light transmitting holes 24b and 24c are too large, the light reflected by the reflection film 24a of the reflection plate 24 becomes weak. Accordingly, the diameters of the light transmitting holes 24b and 24c can secure the intensity of the diffracted light on the detection substrate 18, and there is no direct light passing straight through the light transmitting holes 24b and 24c, and the reflected light It is necessary to have a diameter that can ensure strength.

  In the above-described embodiment, the case where the detection device 10 includes a plurality of photodetectors 18b arranged on the detection substrate 18 has been described. However, the detection device 10 may be mounted on the detection substrate 18 (or the surface substrate 20). Any pattern may be used as long as the pattern of diffracted light can be detected. For example, a camera capable of photographing a diffracted light pattern on the detection substrate 18 (or the front substrate 20) may be used as the detection device 10.

  In the above-described embodiment, the configuration in which the driving device 8 uses the magnetic force to rotate the movable portion 6 around the yaw axis while rolling the periphery of the movable portion 6 on the reference plane P has been described. In addition to the above, various forms can be used. For example, the driving device 8 may be configured to rotationally drive the movable unit 6 around the yaw axis while rolling the periphery of the movable unit 6 on the reference plane P using electrostatic force.

  As mentioned above, although the Example of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

2: optical deflector; 4: base; 6: movable part; 8: driving device; 10: detection device; 12: processing device; 14: support substrate; 16: support layer; 16a: central hole; 18: Detection substrate; 18a: Center hole; 18b: Photodetector; 20: Surface substrate; 20a: Center hole; 22: Supporting column; 24: Reflector; 24a: Reflection film; 24b: Light transmission hole; 28a: electromagnet; 28b: electromagnet; 28c: electromagnet; 28d: electromagnet; 28e: electromagnet; 28f: electromagnet; 30: non-light emitting area;

Claims (6)

A base having a reference surface;
A movable part comprising a reflecting part for reflecting light and at least two light-transmitting parts for transmitting light, the movable part being supported by the base so as to be rotatable while rolling the periphery on a reference plane;
A driving device for rotationally driving the movable part;
A detection device for detecting a pattern of diffracted light diffracted by at least two light transmitting portions;
An optical deflector including a processing device that identifies a state of a movable portion based on a pattern of diffracted light.   The processing device specifies a shape of zero-order light due to interference of diffracted light diffracted by at least two light-transmitting portions in the pattern of diffracted light, and specifies an angle of attack of the reflecting portion from the shape of the zero-order light. Light deflector.   The optical deflector according to claim 2, wherein the processing device specifies the rotation angle of the zero-order light in the pattern of diffracted light, and specifies the azimuth angle of the reflecting portion from the rotation angle of the zero-order light. The movable part is supported on the base by a support column protruding upward from the reference plane,
The processing device identifies the shape of the non-light-projecting area where the diffracted light from at least one light-transmitting part is not projected as a shadow of the support in the diffracted light pattern, and the support post of the movable part is determined from the shape of the non-projection area The optical deflector according to any one of claims 1 to 3, wherein a deviation amount with respect to is specified.   5. The optical deflector according to claim 4, wherein the processing device specifies a rotation angle of the non-light projection region in the diffracted light pattern and specifies a rotation speed of the movable portion from a change with time of the rotation angle of the non-light projection region.   The optical deflector according to claim 1, wherein a peripheral edge of the movable portion has an elliptical shape.