JP2012026936A - Sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor device capable of detecting an object existing in front of a planar irradiated surface.SOLUTION: A sensor device comprises a timing management part 414 that outputs a timing signal at a timing corresponding to each of discrete scan points of a light beam LB1 on an irradiated surface 410a. A signal processing part 415 comprises: an image generation part 415a that stores an output of an optical detection part 404 as a reference signal in a memory 416 based on the timing signal corresponding to each of the discrete scan points of the light beam LB1 when a detection target space 405 contains no object 406, and generates an image in which a difference between the reference signal and a detection signal including the output of the optical detection part 404 based on the timing signal corresponding to each scan point after the reference signal is stored in the memory 416 is set as a pixel value for each scan point; and an object extraction part 415b that extracts the object 406 existing in the detection target space 405 based on the image generated by the image generation part 415a.

Description

  The present invention relates to a sensor device.

  Conventionally, an object recognition sensor having a configuration shown in FIG. 12 has been proposed (Patent Document 1). This object recognition sensor includes a light emitting element 501 that emits a light beam α, a light beam shaping lens 502, an optical scanner 503 that scans the light beam α two-dimensionally, a light receiving element 504, and a scanner drive. A circuit 505 and a signal processing unit 506 are provided.

  The above-described light emitting element 501 is configured by a semiconductor laser element, a light emitting diode, or the like. The light beam shaping lens 502 is provided for condensing or collimating the light beam α emitted from the light emitting element 501.

  The optical scanner 503 includes a vibration plate 511 and a piezoelectric element 512. The vibration plate 511 is formed of a silicon thin plate material. A scanning portion 514 is provided at one end of an axial elastic deformation portion (torsion bar) 513 that resonates in a bending deformation mode and a torsional deformation mode, and vibration is generated at the other end. An input unit 515 is provided. On the surface of the scanning unit 514, a mirror surface (not shown) is formed by performing mirror processing. A laminated piezoelectric element 512 is bonded to the vibration input unit 515. Therefore, the vibration plate 511 is supported by the piezoelectric element 512 in the vibration input unit 515, and the scan unit 514 is supported by the elastic deformation unit 513.

  The light receiving element 504 is configured by a photodiode or the like.

Further, the scanner drive circuit 505 includes an AC voltage V _B (t) having a frequency equal to the resonance frequency in the bending deformation mode of the elastic deformation portion 513 and an AC voltage V _T (t) having a frequency equal to the resonance frequency in the torsion deformation mode. Is applied to the piezoelectric element 512. Therefore, the elastic deformation portion 513, bending twisting and vibration of the deformation mode performs deformation mode vibration at the same time, rotates the scanning unit 514 in the vertical and horizontal (rotation of theta _B direction in FIG. 12 is a vertical direction times dynamic, theta _T direction of rotation is the rotation of the left-right direction). As a result, the optical scanner 503 can continuously scan the light beam α emitted from the light emitting element 501 within the two-dimensional scanning region 507.

In the object recognition sensor described above, since the scanning angle of the light beam α (or the deflection angle of the scanning unit 514) can be known by detecting the voltage V (t) applied to the piezoelectric element 512, the piezoelectric element The applied voltage values V _B (t) and V _T (t) to 512 are output from the scanner drive circuit 505 to the signal processing unit 506 as scanning angle information (or deflection angle information) 510.

  In this object recognition sensor, when the object 508 exists in the scanning region 507 of the light beam α, the light beam α emitted from the light emitting element 501 and scanned by the optical scanner 503 is incident on the surface of the object 508 and reflected. The scattered light reflected by the object 508 is received by the light receiving element 504, and the presence of the object 508 is detected. Here, in the object recognition sensor, the light reception signal 509 of the light receiving element 504 is input to the signal processing unit 506. When the signal processing unit 506 receives the light reception signal 509 from the light receiving element 504, the signal processing unit 506 reads the scanning angle information 510 at that moment, converts it into coordinates, and detects the two-dimensional position of the object 508.

  Patent Document 1 describes that an object recognition sensor can be used in the fields of a code reader, a human body detection sensor, a two-dimensional photoelectric sensor, and the like.

JP-A-6-44398

  By the way, in the sensor device such as the object recognition sensor having the configuration shown in FIG. 12, a member (for example, a planar irradiated surface in which the light beam α is scanned two-dimensionally in the scanning region 507 of the light beam α (for example, , Screen, wall, stage, etc.), even when there is no object 508 in front of the irradiated surface, the light receiving intensity of the light receiving element 504 depends on the scanning angle of the light beam α (or the swing angle of the scanning unit 514). There is a concern that the object 508 cannot be recognized correctly. In short, the object recognition sensor having the configuration shown in FIG. 12 is easily affected by the background of the object 508 in the scanning region 507.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide a sensor device capable of detecting an object existing in front of a planar irradiated surface.

  The sensor device of the present invention includes a light source that emits a light beam, and the light beam emitted from the light source is reflected to a detection target space side so that the light beam is on a planar irradiated surface in the detection target space. A two-dimensionally scanable deflector, a drive unit for generating a drive signal for driving the deflector, and the light beam reflected by the deflector and reflected by the detection target space side to receive the received light amount A light detection unit that generates an output according to the timing, a timing management unit that outputs a timing signal at a timing corresponding to each of the discrete scanning points of the light beam on the irradiated surface based on the drive signal, and A signal processing unit that performs signal processing on the output of the light detection unit based on a timing signal; and a memory that can store the output of the light detection unit, wherein the signal processing unit includes an object in the detection target space. Shi The output of the light detection unit is stored as a reference signal in the memory based on the timing signal corresponding to each of the discrete scanning points of the light beam on the irradiated surface, and stored in the memory. The difference between the reference signal and the detection signal composed of the output of the light detection unit based on the timing signal corresponding to each scanning point after the reference signal is stored in the memory is a pixel value for each scanning point. And an object extraction unit that extracts the object existing in the detection target space based on the image generated by the image generation unit.

  In this sensor device, it is preferable that the timing management unit instructs the signal processing unit to rewrite the reference signal of the memory at each preset time.

  The sensor device includes an operation unit for instructing to update the reference signal, and when the timing management unit receives the instruction signal from the operation unit, the timing management unit is stored in the memory with respect to the signal processing unit. It is preferable to instruct rewriting of the reference signal.

  In this sensor device, the deflector includes an outer frame portion, a movable frame portion arranged inside the outer frame portion and supported by the outer frame portion via a pair of first twisted spring portions, and the movable frame portion. Reflects the light beam supported by the movable frame portion through a pair of second twisted ribs positioned inside the frame and arranged in parallel to the direction in which the first twisted ribs are juxtaposed. A mirror portion having a mirror surface to be formed, a first fixed electrode provided on the movable frame portion side in the outer frame portion, and a first movable electrode provided on the outer frame portion side in the movable frame portion. An electrode, a second fixed electrode provided on the mirror part side in the movable frame part, and a second movable electrode provided on the movable frame part side in the mirror part. The driving unit is configured to switch between the first movable electrode and the first fixed electrode and between the second movable electrode and the second fixed electrode so that the light beam is scanned in the horizontal direction. A horizontal drive circuit for applying a drive voltage of a first drive frequency to the first movable electrode and between the first fixed electrode and the second movable electrode so that the light beam is scanned in the vertical direction. It is preferable to have a vertical drive circuit that applies a drive voltage of the second drive frequency to the other side between the second fixed electrodes.

  In this sensor device, a half mirror that reflects and transmits the light beam is provided between the light source and the deflector, the optical axis between the light source and the deflector, and between the deflector and the light detection unit. The optical axis is preferably matched between the deflector and the half mirror.

  In the sensor device of the present invention, it is possible to detect an object existing in front of a planar irradiated surface.

The sensor apparatus of embodiment is shown, (a) is a schematic block diagram, (b) is a principal part block diagram. (A) shows the other example of a structure of a sensor apparatus same as the above, (b), (c) is operation | movement explanatory drawing. It is operation | movement explanatory drawing of a sensor apparatus same as the above. It is a schematic exploded perspective view of the deflector in a sensor apparatus same as the above. It is a schematic perspective view of the deflector in a sensor apparatus same as the above. It is principal process sectional drawing for demonstrating the manufacturing method of the deflector in a sensor apparatus same as the above. It is operation | movement explanatory drawing of a sensor apparatus same as the above. It is operation | movement explanatory drawing of a sensor apparatus same as the above. (A) shows the other example of a structure of a sensor apparatus same as the above, (b)-(d) is operation | movement explanatory drawing. It is explanatory drawing of the application example of the other structural example of a sensor apparatus same as the above. It is operation | movement explanatory drawing of another structural example of a sensor apparatus same as the above. It is a schematic block diagram of the object recognition sensor of a prior art example.

  Hereinafter, the sensor device of the present embodiment will be described with reference to FIGS.

  The sensor device emits a light beam LB1 and a planar irradiated surface 410a that reflects the light beam LB1 emitted from the light source 401 toward the detection target space 405 and causes the light beam LB1 to be in the detection target space 405. A deflector 403 capable of two-dimensional scanning is provided. Here, the deflector 403 can scan the light beam LB1 in the vertical direction and the horizontal direction. Therefore, the light beam scanning apparatus can scan the light beam LB1 in the vertical direction and the horizontal direction on the planar irradiated surface 410a as shown in FIGS. 1A and 2, for example.

  The sensor device also receives a drive unit 413 that generates a drive signal for driving the deflector 403, and the light beam LB1 reflected by the deflector 403 and reflected by the detection target space 405, and outputs an output corresponding to the amount of received light. And a generated light detection unit 404.

  Furthermore, the sensor device outputs a timing signal at a timing corresponding to each of the discrete scanning points 450 (see FIG. 3) of the light beam LB1 on the irradiated surface 410a based on the drive signal, A signal processing unit 415 that performs signal processing on the output of the light detection unit 404 based on a timing signal from the timing management unit 414; The sensor device recognizes the object 406 by the signal processing unit 415. The sensor device also includes a memory 416 that can store the output of the light detection unit 404.

  In addition, the sensor device includes a half mirror 402 that reflects and transmits the light beam LB1 between the light source 401 and the deflector 403. Here, as shown in FIG. 2A, the sensor device includes an optical axis OA1 between the light source 401 and the deflector 403 and an optical axis OA2 between the deflector 403 and the light detection unit 404. The half mirrors 402 are preferably matched.

  In addition, as shown in FIG. 2A, the sensor device places a light beam LB1 positioned between the half mirror 402 and the light detection unit 404 and reflected by the half mirror 402 on the light receiving surface 404a of the light detection unit 404. It is preferable to provide a lens 407 that collects light. 2, the one-dot chain line in (a) indicates the optical axis, and the solid line arrow in (b) indicates the travel path of the detection light beam LB1 emitted from the detection light source 401 to the detection target space 405. The solid line arrow in (c) indicates the traveling path of the detection light beam LB1 reflected by the irradiated surface 410a.

  As the light source 401, a semiconductor laser that emits infrared light as the light beam LB1 is used. The light source 401 is not particularly limited as long as it can emit the light beam LB1, and may be, for example, a light emitting diode. Further, the wavelength of the light beam LB1 is not particularly limited.

  The deflector 403 is configured by a MEMS mirror (MEMS optical scanner) which is a MEMS (micro electro mechanical systems) device. Specifically, as shown in FIGS. 4, 5, and 6 (f), the deflector 403 is formed using an SOI (Silicon on Insulator) substrate 100 that is a semiconductor substrate, and a mirror surface 21 on the movable portion 20. Is provided. Further, the deflector 403 includes a first cover substrate 2 bonded to one surface of the mirror forming substrate 1 where the mirror surface 21 is provided. Further, the deflector 403 includes a second cover substrate 3 bonded to the other surface side of the mirror forming substrate 1.

The mirror forming substrate 1 is formed by processing the above-described SOI substrate 100 by a bulk micromachining technique or the like. In this SOI substrate 100, an insulating layer (SiO ₂ layer) 100c is interposed between a conductive first silicon layer (active layer) 100a and a second silicon layer (silicon substrate) 100b. In the SOI substrate 100, the thickness of the first silicon layer 100a is set to 30 μm, and the thickness of the second silicon layer 100b is set to 400 μm. However, these numerical values are examples, and are not particularly limited. Absent. The surface of the first silicon layer 100a, which is one surface of the SOI substrate 100, is a (100) plane.

  The mirror forming substrate 1 includes an outer frame portion 10, the above-described movable portion 20 disposed inside the outer frame portion 10, and an outer frame portion 10 disposed so as to sandwich the movable portion 20 inside the outer frame portion 10. A pair of first torsion spring portions 30 and 30 connected to the movable portion 20 are provided. Each of the first torsion spring portions 30 and 30 can be torsionally deformed.

  The outer frame portion 10 has a frame shape (here, a rectangular frame shape), and each of an outer peripheral shape and an inner peripheral shape is formed in a rectangular shape. Here, in the deflector 403, the outer peripheral shape of each of the mirror forming substrate 1 and each of the cover substrates 2 and 3 is rectangular, and the outer dimensions of each of the cover substrates 2 and 3 are matched with the outer dimensions of the mirror forming substrate 1. It is.

  The outer frame portion 10 of the mirror forming substrate 1 is formed using the first silicon layer 100a, the insulating layer 100c, and the second silicon layer 100b of the SOI substrate 100, respectively. In the mirror forming substrate 1, a portion of the outer frame portion 10 formed by the first silicon layer 100 a is joined to the outer peripheral portion of the first cover substrate 2 over the entire periphery. Of these, the portion formed by the second silicon layer 100 b is bonded to the outer periphery of the second cover substrate 3 over the entire periphery.

  Further, the movable part 20 and the first torsion spring parts 30, 30 of the mirror forming substrate 1 are formed using the first silicon layer 100 a of the SOI substrate 100 and are sufficiently thinner than the outer frame part 10. It has become. The mirror surface 21 provided on the movable part 20 reflects the light beam LB1 from the light source 401, and a metal film (on the part formed by the first silicon layer 100a in the movable part 20). For example, it is constituted by the surface of the reflective film 21a made of an Al—Si film or the like. In the present embodiment, the thickness of the reflective film 21a is set to 500 nm, but this numerical value is an example and is not particularly limited.

  In the following, as shown on the left side of FIG. 4, the direction orthogonal to the parallel arrangement direction of the pair of first torsion springs 30, 30 in plan view is the x-axis direction, and the pair of first torsion springs 30, 30. In the following description, the parallel arrangement direction is defined as the y-axis direction, and the direction orthogonal to the x-axis direction and the y-axis direction is defined as the z-axis direction.

  In the mirror forming substrate 1, a pair of first torsion spring portions 30, 30 are arranged in parallel in the y-axis direction, and the movable portion 20 is a pair of first torsion spring portions 30, 30 with respect to the outer frame portion 10. It can be displaced around 30 (it can be rotated around an axis in the y-axis direction). That is, the pair of first torsion spring portions 30, 30 connects the outer frame portion 10 and the movable portion 20 so that the movable portion 20 can swing with respect to the outer frame portion 10. In other words, the movable part 20 disposed inside the outer frame part 10 is connected to the outer frame via two first torsion spring parts 30 and 30 that are continuously and integrally extended in two opposite directions from the movable part 20. The part 10 is supported so as to be swingable. Here, the pair of first torsion spring portions 30 and 30 are formed such that a straight line connecting the center lines along the y-axis direction passes through the center of gravity of the movable portion 20 in plan view. Each of the torsion spring portions 30 and 30 has a thickness dimension (dimension in the z-axis direction) set to 30 μm and a width dimension (dimension in the x-axis direction) set to 5 μm, but these numerical values are examples. There is no particular limitation. Further, the inner peripheral shape of the outer frame portion 10 is not limited to a rectangular shape, and may be a circular shape, for example.

  The mirror forming substrate 1 described above is perpendicular to the direction in which the pair of first torsion spring portions 30 and 30 are connected in the movable portion 20 (the direction in which the pair of first torsion spring portions 30 and 30 are juxtaposed) (that is, Comb-shaped first movable electrodes 22 formed on both sides in the x-axis direction) are provided. Further, the mirror forming substrate 1 is a comb-shaped first fixed electrode 12 having a plurality of fixed comb teeth 12 b formed on the outer frame portion 10 and facing the plurality of movable comb teeth 22 b of the first movable electrode 22. It has. Here, the mirror forming substrate 1 is applied between the first movable electrode 22 and the first fixed electrode 12 by applying a drive voltage between the first movable electrode 22 and the first fixed electrode 12. The movable part 20 is swung by the electrostatic force generated in the above. This operation will be described later.

  The first fixed electrode 12 has a comb shape in plan view, and a portion of the outer frame portion 10 formed by the first silicon layer 100a in the frame piece portion along the y-axis direction is comb-shaped. The bone part 12a is comprised. The first fixed electrode 12 has a pair of fixed comb teeth 12b on the surface facing the movable portion 20 in the comb bone portion 12a (inner side surface along the y-axis direction in the outer frame portion 10). The torsion spring portions 30 are arranged in a line along the direction in which the torsion spring portions 30 and 30 are juxtaposed. Here, each fixed comb tooth piece 12b is constituted by a part of the first silicon layer 100a.

  On the other hand, the first movable electrode 22 is a fixed comb on the side surface (side surface along the y-axis direction in the movable portion 20) of the comb portion 12 a on the comb bone portion 12 a side of the first fixed electrode 12 in the movable portion 20. A large number of movable comb teeth 22b respectively facing the teeth 12b are arranged in the parallel direction. Here, each movable comb-tooth piece 22b is constituted by a part of the first silicon layer 100a.

  In the first fixed electrode 12 and the first movable electrode 22, the comb bone portions 12 a and 22 a face each other, and each fixed comb tooth piece 12 b of the first fixed electrode 12 corresponds to the first movable electrode 22. The fixed comb teeth 12b and the movable comb teeth 22b are spaced apart from each other in the y-axis direction. Therefore, in the mirror forming substrate 1, a voltage is applied between the first fixed electrode 12 and the first movable electrode 22, whereby the first fixed electrode 12 and the first movable electrode 22 are interposed. An electrostatic force is generated that acts in a direction that attracts each other. In addition, what is necessary is just to set the clearance gap between the fixed comb-tooth piece 12b and the movable comb-tooth piece 22b in a y-axis direction suitably in the range of about 2 micrometers-5 micrometers, for example.

  By the way, the movable part 20 includes a frame-like (here, rectangular frame-like) movable frame part 23 supported by the outer frame part 10 through a pair of first torsion spring parts 30 and 30 in a swingable manner, A mirror part 24 provided inside the movable frame part 23 and provided with a mirror surface 21 and a mirror part 24 arranged inside the movable frame part 23 so as to sandwich the mirror part 24 are connected and twisted. It has a pair of 2nd torsion spring parts 25 and 25 which can be changed.

  The second torsion spring portions 25, 25 are arranged in parallel in a direction (x-axis direction) orthogonal to the parallel arrangement direction (y-axis direction) of the first torsion spring portions 30, 30. In short, the movable portion 20 has a pair of second torsion spring portions 25, 25 arranged in parallel in the x-axis direction, and the mirror portion 24 is a pair of second torsion spring portions 25 with respect to the movable frame portion 23. , 25 (displaceable around the axis in the x-axis direction). That is, the pair of second torsion spring portions 25, 25 connect the movable frame portion 23 and the mirror portion 24 so that the mirror portion 24 can swing with respect to the movable frame portion 23. In other words, the mirror part 24 disposed inside the movable frame part 23 is movable frame part via two second torsion spring parts 25, 25 extended continuously and integrally from the mirror part 24 in two opposite directions. 23 is swingably supported. Here, the pair of second torsion spring portions 25 and 25 are formed such that a straight line connecting the center lines along the x-axis direction passes through the center of gravity of the mirror portion 24 in plan view. Each second torsion spring portion 25 has a thickness dimension (dimension in the z-axis direction) set to 30 μm and a width dimension (dimension in the y-axis direction) set to 30 μm. However, these numerical values are only examples. There is no particular limitation. Moreover, the planar view shape of the mirror part 24 and the mirror surface 21 is not restricted to a rectangular shape, For example, a circular shape may be sufficient. Further, the inner peripheral shape of the movable frame portion 23 is not limited to a rectangular shape, and may be a circular shape, for example.

  As can be seen from the above description, the mirror portion 24 is configured to rotate around the axis of the pair of first torsion spring portions 30 and 30 and rotate around the axis of the pair of second torsion spring portions 25 and 25. Is possible. In short, the deflector 403 is configured such that the mirror surface 21 of the mirror unit 24 is two-dimensionally rotatable, and can scan the light beam LB2 two-dimensionally. Here, the movable portion 20 is integrally provided with a frame-shaped (rectangular frame-shaped) support body 29 that supports the movable frame portion 23 on the opposite side of the movable frame portion 23 to the first cover substrate 2 side. The support 29 can be rotated integrally with the movable frame portion 23.

  Further, the mirror forming substrate 1 is perpendicular to the direction connecting the pair of second torsion spring portions 25, 25 in the mirror portion 24 (ie, the direction in which the pair of second torsion spring portions 25, 25 are juxtaposed) (that is, Comb-shaped second movable electrode 27 formed on both sides in the y-axis direction) and a plurality of fixed comb teeth formed on movable frame portion 23 and opposed to a plurality of movable comb-teeth pieces 27b of second movable electrode 27 And a comb-shaped second fixed electrode 26 having a piece 26b. Here, the mirror forming substrate 1 is applied between the second movable electrode 27 and the second fixed electrode 26 by applying a driving voltage between the second movable electrode 27 and the second fixed electrode 26. The mirror portion 24 swings due to the electrostatic force generated in the above. This operation will be described later.

  The above-described second fixed electrode 26 has a comb shape in plan view, and the comb bone portion 26 a is constituted by a part of the movable frame portion 23. A large number of fixed comb teeth pieces 26b are formed on a surface facing the mirror portion 24 of the comb portion 26a of the second fixed electrode 26 (an inner surface along the x-axis direction of the movable frame portion 23). The second torsion spring portions 25 are arranged in a line along the direction in which the second torsion spring portions 25 and 25 are juxtaposed. On the other hand, the second movable electrode 27 is configured by a part of the mirror portion 24, and the side surface of the second fixed electrode 26 on the side of the comb portion 26 a (the side surface along the x-axis direction in the mirror portion 24). A large number of movable comb teeth 27b facing the fixed comb teeth 26b are arranged in the parallel direction. Here, in the comb-shaped second fixed electrode 26 and the comb-shaped second movable electrode 27, the comb bone portions 26a and 27a are opposed to each other, and each fixed comb tooth piece 26b of the second fixed electrode 26 is The fixed comb tooth piece 26b and the movable comb tooth piece 27b are spaced apart from each other in the x-axis direction. Therefore, the mirror forming substrate 1 is applied between the second fixed electrode 26 and the second movable electrode 27 by applying a voltage between the second fixed electrode 26 and the second movable electrode 22. Electrostatic forces acting in the direction of attracting each other are generated. In addition, what is necessary is just to set the clearance gap between the fixed comb-tooth piece 26b in the x-axis direction and the movable comb-tooth piece 27b suitably in the range of about 2 micrometers-5 micrometers, for example.

  Further, the mirror forming substrate 1 is arranged in parallel at substantially equal intervals on the outer frame portion 10 so that the three pads 13 are aligned in a straight line in a plan view. On the other hand, the first cover substrate 2 is provided with three through holes 202 that expose the pads 13 separately. Each pad 13 has a circular shape in plan view, and is composed of a metal film (for example, an Al—Si film). In this embodiment, the film thickness of each pad 13 is set to 500 nm, but this numerical value is an example and is not particularly limited.

  The mirror forming substrate 1 is formed with a plurality of (here, three) slits 10 a in the portion formed by the first silicon layer 100 a in the outer frame portion 10, and the first in the movable frame portion 23 of the movable portion 20. A plurality of (here, four) slits 20a are formed in a portion formed by the silicon layer 100a. Thereby, in the mirror forming substrate 1, the middle pad 13 (13b) in FIG. 4 among the three pads 13 is electrically connected to the first fixed electrode 12 to have the same potential, and the right pad 13 (13a). Are electrically connected to the first movable electrode 22 and the second movable electrode 26 to have the same potential, and the left pad 13 (13c) is electrically connected to the second movable electrode 27 of the mirror portion 24. The potential is the same.

  Here, the plurality of slits 10a of the outer frame portion 10 are formed with a depth reaching the insulating layer 100c. The deflector 403 employs a structure in which the slits 10a are formed in the outer frame part 10 by forming each slit 10a as a trench and making the shape of each slit 10a in plan view not open to the outer surface side of the outer frame part 10. However, it is possible to prevent the bondability between the outer frame portion 10 and the first cover substrate 2 from being lowered, and to ensure the airtightness of the space surrounded by the outer frame portion 10 and the cover substrates 2 and 3. Yes.

  In addition, each slit 20a of the movable frame portion 23 in the movable portion 20 is a trench, and the above-described support 29 is configured by a part of the insulating layer 100c of the SOI substrate 100 and a part of the second silicon layer 100b. The depth reaches the insulating layer 100c. In short, the deflector 403 employs a configuration in which a plurality of slits 20 a are formed in the movable frame portion 23, but the movable frame portion 23 and the support 29 have the shafts of the pair of first torsion spring portions 30 and 30. It is possible to rotate integrally around. Here, the support 29 is formed in a frame shape that covers a portion of the movable frame portion 23 excluding each fixed comb tooth piece 26b and each movable comb tooth piece 22b (see FIG. 5). In addition, the plurality of slits 20a of the movable frame portion 23 is such that the center of gravity of the movable portion 20 including the support 29 has a center line along the y-axis direction of the pair of first torsion spring portions 30 and 30 in plan view. The shape is designed so that it is located approximately in the middle of the connecting straight line. Accordingly, in the deflector 403 in the present embodiment, the movable portion 20 smoothly swings around the axis of the pair of first torsion spring portions 30 and 30, and the reflected light is scanned appropriately. In the present embodiment, the thickness of the portion constituted by the second silicon layer 100b in the support 29 is set to the same thickness as the portion constituted by the second silicon layer 100b in the outer frame portion 10. However, it is not limited to the same, and may be thicker or thinner.

  The first cover substrate 2 is formed by using a first glass substrate 200 formed by stacking and joining two glass plates each made of Pyrex (registered trademark) glass in the thickness direction. . The second cover substrate 3 is formed using a second glass substrate 300 made of Pyrex (registered trademark) glass or the like. In addition, although the thickness of the 1st glass substrate 200 and the 2nd glass substrate 300 is set in the range of about 0.5 mm-1.5 mm, these numerical values are an example and it does not specifically limit it. Absent.

  The first cover substrate 2 uses the first glass substrate 200 as described above, and penetrates in the thickness direction of the first glass substrate 200 to expose each pad 13 over the entire circumference. A through hole 202 is formed. Here, each through hole 202 of the first glass substrate 200 is formed in a tapered shape in which the opening area gradually increases as the distance from the mirror forming substrate 1 increases. Each through-hole 202 is formed by sandblasting. The method of forming each through-hole 202 is not limited to the sand blast method, and a drilling method, an etching method, or the like may be employed.

  The deflector 403 has a circular shape in plan view of each pad 13 so that the opening diameter of each through-hole 202 on the first mirror forming substrate 1 side is larger than the diameter of each pad 13. is there. The diameter of each pad 13 is set to 0.5 mm, but is not particularly limited. Further, the planar view shape of each pad 13 is not necessarily a circular shape, and may be a square shape, for example, but in order to reduce the opening diameter of each through hole 202, the circular shape is more preferable than the square shape. preferable.

  By the way, when a part of each pad 13 overlaps with the first cover substrate 2 in the thickness direction, the bondability and airtightness are impaired by the influence of the thickness of each pad 13, and the yield during manufacture is reduced and the operation is stable. There is concern that it may cause a decrease in stability and stability over time. Therefore, in such a case, it is necessary to increase the width dimension of the outer frame portion 10 (the distance between the outer surface and the inner surface of the outer frame portion 10), and the size reduction of the deflector 403 is limited. It is possible.

  On the other hand, in the deflector 403 according to the present embodiment, the first cover substrate 2 does not overlap each pad 13, and one pad 13 is provided between the first cover substrate 2 and the outer frame portion 10. There is no intervening part. Therefore, the deflector 403 can prevent the bonding between the first cover substrate 2 and the outer frame portion 10 of the mirror forming substrate 1 from being hindered by the pads 13. As a result, in the deflector 403 in the present embodiment, it is possible to prevent the bondability and airtightness from being impaired due to the influence of the thickness of each pad 13, and the yield can be increased without increasing the width dimension of the outer frame portion 10. The cost can be reduced by the improvement, and the decrease in the operational stability and the temporal stability can be suppressed.

  Further, in the deflector 403, the movable portion 20 is configured while reducing power consumption by making the airtight space surrounded by the outer frame portion 10 of the mirror forming substrate 1 and the cover substrates 2 and 3 a vacuum (vacuum atmosphere). In addition, the mechanical deflection angle of the mirror unit 24 can be increased. Therefore, in the deflector 403, the airtight space is evacuated and non-evaporated to an appropriate portion inside the portion of the second cover substrate 3 facing the mirror forming substrate 1 that is joined to the outer frame portion 10. A mold getter (not shown) is provided. The non-evaporable getter may be formed of, for example, an alloy containing Zr as a main component or an alloy containing Ti as a main component. Further, in the deflector 403, the airtight space surrounded by the outer frame portion 10, the first cover substrate 2, and the second cover substrate 3 may be an inert gas atmosphere (for example, a dry nitrogen gas atmosphere). Good. In the above-described deflector 403, the mirror surface 21 can be prevented from being oxidized regardless of whether the airtight space is a vacuum atmosphere or an inert gas atmosphere. It is possible to suppress the change with time of the reflection characteristics.

  The first glass substrate 200 has a first recess 201 for securing a displacement space of the movable portion 20 on the surface facing the mirror forming substrate 1. Here, the first glass substrate 200 is formed by joining two glass plates as described above. Therefore, the first glass substrate 200 penetrates in a thickness direction in a portion corresponding to the first recess 201 in a glass plate (hereinafter referred to as a first glass plate) disposed on the side close to the mirror forming substrate 1. A glass plate (hereinafter referred to as a second glass plate) that forms the aperture and is disposed on the side far from the mirror-forming substrate 1 has a flat plate shape. Therefore, the first glass substrate 200 can have a smooth surface on the inner bottom surface of the first recess 201 as compared with the case where the first recess 201 is formed by sandblasting or the like. Diffuse reflection, light diffusion, scattering loss, and the like on the inner bottom surface of 201 can be reduced.

  Further, the second cover substrate 3 has a second recess 301 for securing a displacement space of the movable portion 20 formed on the one surface of the second glass substrate 300 on the mirror forming substrate 1 side.

  Here, when forming the 2nd recessed part 301 in the said one surface of the 2nd glass substrate 300, what is necessary is just to form by the sandblasting method etc., for example. Similarly to the first cover substrate 2, the second cover substrate 3 may be formed by joining two glass plates. A glass plate (hereinafter referred to as a glass plate disposed on the side close to the mirror forming substrate 1). A glass plate (hereinafter referred to as a fourth glass plate) disposed on the side far from the mirror forming substrate 1 while forming an opening portion penetrating in the thickness direction at a portion corresponding to the second recess 301 in the third glass plate). (Referred to as a glass plate) may be flat. Since the second cover substrate 3 does not need to transmit light, the second cover substrate 3 is not limited to the second glass substrate 300 but can be easily bonded to the mirror forming substrate 1 and is made of a material of the semiconductor substrate (SOI substrate 100). A substrate formed of a material having a small difference in linear expansion coefficient from Si may be used. For example, the substrate may be formed using a silicon substrate. In this case, the second recess 301 is formed by a photolithography technique and an etching technique. What is necessary is just to form using.

  Further, in the deflector 403 according to the present embodiment, the airtight space surrounded by the outer frame portion 10, the first cover substrate 2 and the second cover substrate 3 is evacuated so that the power consumption can be reduced. Since the mechanical deflection angle of the portion 20 can be increased, the airtight space is evacuated and the getter described above is disposed on the inner bottom surface of the second recess 301.

  In the present embodiment, the thicknesses of the first cover substrate 2 and the second cover substrate 3 are set in a range of about 0.5 mm to 1.5 mm, and the first concave portion 201 and the second concave portion 301 are formed. Although the depth is set in the range of 300 μm to 800 μm, these numerical values are merely examples, and may be set appropriately according to the amount of displacement of the movable part 20 in the z-axis direction (that is, the rotation of the movable part 20). The depth is not particularly limited as long as the depth does not hinder dynamic movement.

  As described above, Pyrex (registered trademark), which is borosilicate glass, is employed as the glass material of each glass substrate 200, 300, but is not limited to borosilicate glass, for example, soda lime glass, non-alkali glass, Quartz glass or the like may be employed.

  Hereinafter, the manufacturing method of the deflector 403 will be described with reference to FIG. 6, and FIGS. 6A to 6F show schematic cross sections of a portion corresponding to the cross section AB in FIG. 4.

  First, by performing an oxide film forming step of forming silicon oxide films 111a and 111b on the one surface side and the other surface side of the SOI substrate 100, which is a semiconductor substrate, by thermal oxidation or the like, FIG. Get the structure shown.

  Thereafter, a first silicon oxide film patterning step for patterning the silicon oxide film (hereinafter referred to as the first silicon oxide film) 111a on the one surface side of the SOI substrate 100 is performed using a photolithography technique and an etching technique. As a result, the structure shown in FIG. In the first silicon oxide film patterning step, the portion of the first silicon oxide film 111a corresponding to the portion other than the region where the reflective film 21a is to be formed in the movable portion 20, the first torsion spring portions 30, 30 and the like. The first silicon oxide film 111a is patterned so as to leave the above.

  After the first silicon oxide film patterning step, a metal film (for example, an Al—Si film) having a predetermined film thickness (for example, 500 nm) is formed on the one surface side of the SOI substrate 100 by a sputtering method, an evaporation method, or the like. FIG. 6C shows a metal film patterning process for forming each pad 13 and the reflective film 21a by performing a metal film forming process and patterning the metal film using a photolithography technique and an etching technique. Get the structure. In this embodiment, since the material and film thickness of each pad 13 and the reflective film 21a are set to be the same, each pad 13 and the reflective film 21a are formed simultaneously. When the material and film thickness of the film 21a are different, the pad forming process for forming each pad 13 and the reflective film forming process for forming the reflective film 21a may be provided separately.

  After forming each of the pads 13 and the reflective film 21a, the movable frame portion 23, the mirror portion 24, and the pair of first torsion spring portions 30 in the first silicon layer 100a are formed on the one surface side of the SOI substrate 100. 30 corresponding to the pair of second torsion spring portions 25, 25, the outer frame portion 10, the first fixed electrode 12, the second movable electrode 22, the second fixed electrode 26, and the second movable electrode 27. A first resist layer 130 patterned so as to cover the portion is formed. Thereafter, by using the first resist layer 130 as a mask, a first silicon layer patterning step (surface-side patterning step) for patterning the first silicon layer 100a is performed to obtain the structure shown in FIG. In the first silicon layer patterning step, the first silicon layer 100a is etched to a depth that reaches the insulating layer 100c (first predetermined depth). Etching of the first silicon layer 100a in the first silicon layer patterning step may be performed by a dry etching apparatus capable of highly anisotropic etching, such as an inductively coupled plasma etching apparatus. In the first silicon layer patterning step, the insulating layer 100c is used as an etching stopper layer.

  After the first silicon layer patterning step, the first resist layer 130 on the one surface side of the SOI substrate 100 is removed. Thereafter, a second resist layer 131 is formed on the entire surface of the SOI substrate 100 on the one surface side. Subsequently, on the other surface side of the SOI substrate 100, a third resist layer 132 patterned so as to expose portions other than the portions corresponding to the outer frame portion 10 and the support 29 in the second silicon layer 100b is formed. . Thereafter, a second silicon layer patterning step of patterning the second silicon layer 100b is performed using the third resist layer 132 as a mask, thereby obtaining the structure shown in FIG. In the second silicon layer patterning step, the second silicon layer 100b is etched to a depth that reaches the insulating layer 100c (second predetermined depth). Etching of the second silicon layer 100b in the second silicon layer patterning step may be performed by a dry etching apparatus having high anisotropy and capable of vertical deepening, such as an inductively coupled plasma etching apparatus. In the second silicon layer patterning step, the insulating layer 100c is used as an etching stopper layer.

  After the second silicon layer patterning step, the mirror forming substrate 1 is formed by performing an insulating layer patterning step of etching unnecessary portions of the insulating layer 100c of the SOI substrate 100 from the other surface side of the SOI substrate 100. Subsequently, the second resist layer 131 and the third resist layer 132 are removed. Thereafter, by performing a joining step of joining the mirror forming substrate 1 to the first cover substrate 2 and the second cover substrate 3 by anodic bonding or the like, the deflector 403 having the structure shown in FIG. 6F is obtained. .

  In the above-described bonding process, from the viewpoint of protecting the mirror surface 21 of the mirror forming substrate 1, after performing the first bonding process of bonding the first cover substrate 2 and the mirror forming substrate 1, It is preferable to perform a second joining process for joining the second cover substrate 3. Here, in the first bonding process, first, a laminated body in which the first cover substrate 2 in which the first concave portion 201 and each through hole 202 are formed on the first glass substrate 200 and the mirror forming substrate 1 are overlapped. Is heated to a predetermined bonding temperature (for example, about 300 ° C. to 400 ° C.) in a vacuum with a predetermined degree of vacuum (for example, 10 Pa or less), between the first silicon layer 100a and the first cover substrate 2. A predetermined voltage (for example, about 400 V to 800 V) may be applied between the first cover substrate 2 side and the low potential side, and this state may be maintained for a predetermined bonding time (for example, about 20 minutes to 60 minutes). . In the second bonding process, anodic bonding between the second silicon layer 100b and the second cover substrate 3 is performed in accordance with the first bonding process described above. The bonding method for bonding the mirror forming substrate 1 and the cover substrates 2 and 3 is not limited to anodic bonding, and for example, a room temperature bonding method may be used. In addition, after the first silicon layer patterning step, the SOI substrate 100 and the first cover substrate 2 are bonded together, and then the second silicon layer patterning step and the insulating layer patterning step are performed, so that the mirror forming substrate 1 is formed. Then, the mirror forming substrate 1 and the second cover substrate 3 may be bonded. In manufacturing the deflector 403, the mirror forming substrate 1, the first cover substrate 2, and the second cover substrate 3 are each in a wafer state until the bonding process is completed, and after the bonding process. Thus, a dicing process for separating the individual deflectors 403 may be performed.

  Next, the operation of the deflector 403 will be described.

  In the deflector 403, a pulse voltage for driving the movable portion 20 is applied via the pair of pads 13 and 13 between the first movable electrode 22 and the first fixed electrode 12 facing each other. Electrostatic force is generated between the first movable electrode 22 and the first fixed electrode 12, and the movable portion 20 rotates about the axis in the y-axis direction. Therefore, in the deflector 403, an electrostatic force can be periodically generated by applying a pulse voltage having a predetermined driving frequency between the first movable electrode 22 and the first fixed electrode 12, and the movable portion 20 can be swung.

  Here, the above-described movable portion 20 is not in a horizontal posture (a posture parallel to the xy plane) and is tilted slightly though it is stationary due to internal stress. For example, the first movable electrode 22. When a pulse voltage is applied between the first fixed electrodes 12, even when in a stationary state, a driving force in a direction substantially perpendicular to the movable portion 20 (z-axis direction) is applied, and the movable portion 20 is paired. The pair of first torsion springs 30 and 30 are rotated while being twisted, with the first torsion springs 30 and 30 as rotation axes. When the driving force between the first movable electrode 22 and the first fixed electrode 12 is released when the movable comb tooth piece 22b and the fixed comb tooth piece 12b are completely overlapped, The portion 20 continues to rotate while twisting the pair of first torsion spring portions 30 and 30 by inertial force. Then, when the inertial force in the rotation direction of the movable portion 20 and the restoring force of the pair of first torsion spring portions 30 and 30 become equal, the rotation of the movable portion 20 in the rotation direction stops. To do. At this time, when a pulse voltage is applied again between the first movable electrode 22 and the first fixed electrode 12 to generate an electrostatic force, the movable portion 20 causes the restoring force of the pair of first torsion spring portions 30 and 30. And the driving force between the first movable electrode 22 and the first fixed electrode 12 starts to rotate in the opposite direction. The movable portion 20 repeats the rotation by the driving force between the first movable electrode 22 and the first fixed electrode 12 and the restoring force of the pair of first torsion spring portions 30, 30, and thereby a pair of torsion spring portions. Oscillate about 30 and 30 as pivot axes.

  Note that the application form and frequency of the drive voltage between the first movable electrode 22 and the first fixed electrode 12 are not particularly limited, and for example, between the first movable electrode 22 and the first fixed electrode 12. The applied voltage may be a sine wave voltage.

  By the way, the deflector 403 uses, for example, the first fixed electrode 12 and the second movable electrode with the potential of the pad 13a where the first movable electrode 22 and the second fixed electrode 26 are electrically connected as a reference potential. By periodically changing the potential of each of the electrodes 27, the movable portion 20 can be rotated about the axis of the pair of first torsion spring portions 30, 30, and the mirror portion 24 can be turned to the pair of second torsion springs. The torsion springs 25 and 25 can be rotated around the axis. In short, in the deflector 403 in the present embodiment, a pulse voltage for driving the movable portion 20 is interposed between the opposed first fixed electrode 12 and first movable electrode 22 via the pair of pads 13b and 13a. As a result, an electrostatic force is generated between the first fixed electrode 12 and the first movable electrode 22, and the movable portion 20 rotates around the y-axis direction. Further, in this deflector 403, a pulse voltage for driving the mirror portion 24 is applied between the opposed second fixed electrode 26 and second movable electrode 27 via the pair of pads 13a and 13c. As a result, an electrostatic force is generated between the second fixed electrode 26 and the second movable electrode 27, and the mirror portion 24 rotates about the axis in the x-axis direction. Therefore, in the deflector 403 in the present embodiment, an electrostatic force is periodically generated by applying a pulse voltage having a predetermined first driving frequency between the first fixed electrode 12 and the first movable electrode 22. The entire movable part 20 can be swung, and furthermore, by applying a pulse voltage of a predetermined second driving frequency between the second fixed electrode 26 and the second movable electrode 27, An electrostatic force can be periodically generated, and the mirror part 24 of the movable part 20 can be swung. The mirror forming substrate 1 is formed on the surface of the portion of the first silicon layer 100a where the reflective film 21a is not formed on the space surrounded by the outer frame portion 10 and the first cover substrate 2. A film 111a (see FIG. 6F) is formed.

  In the deflector 403 in the present embodiment, the resonance frequency of the vibration system configured by the movable portion 20 and the pair of first torsion spring portions 30 and 30 between the first fixed electrode 12 and the first movable electrode 22. By applying a pulse voltage having a frequency approximately twice that of the movable portion 20, the movable portion 20 is driven with a resonance phenomenon, and the mechanical deflection angle (inclination with respect to a horizontal plane parallel to the xy plane) is increased. Further, in the deflector 403 in the present embodiment, the vibration system configured by the mirror portion 24 and the pair of second torsion spring portions 25 and 25 is disposed between the second fixed electrode 26 and the second movable electrode 27. By applying a pulse voltage having a frequency approximately twice the resonance frequency, the mirror unit 24 is driven with a resonance phenomenon, and the mechanical deflection angle (parallel to the surface of the movable frame unit 23 on the first cover substrate 2 side) is driven. The inclination with respect to the surface becomes larger.

  By the way, the above-described driving unit 413 applies a driving voltage (driving signal) of the first driving frequency between the second movable electrode 27 and the second fixed electrode 26 so that the light beam LB1 is scanned in the horizontal direction. And a driving voltage (driving signal) having a second driving frequency between the first movable electrode 22 and the first fixed electrode 12 so that the light beam LB1 is scanned in the vertical direction. And a vertical drive circuit (not shown) for applying. Depending on the arrangement of the deflector 403, the horizontal drive circuit may apply a drive voltage of the first drive frequency between the first movable electrode 22 and the first fixed electrode 12, and the vertical drive circuit may A driving voltage having the second driving frequency may be applied between the two movable electrodes 27 and the second fixed electrode 26.

  The light detection unit 404 also includes a light receiving element 404a made of a photodiode having sensitivity to infrared light, an amplification unit 404b that amplifies the output of the light receiving element 404a, and analog-digital conversion of the output of the amplification unit 404b. A / D converter 404c, and the output changes according to the amount of light received by the light receiving element 404a. Therefore, in the sensor device, the amount of light received by the light receiving element 404a of the light detection unit 404 changes and the output changes according to the presence or absence of the object 406 on the optical path of the light beam LB1.

  By the way, the above-described timing management unit 414 generates the first reference pixel timing signal and the second reference pixel timing signal at frequencies that match the first driving frequency and the second driving frequency, respectively. A generation unit 414a, a reference pixel timing adjustment unit 414b that adjusts and outputs phases of the first reference pixel timing signal and the second reference pixel timing signal generated by the reference pixel timing generation unit 414a, and a reference pixel timing A corresponding pixel calculation unit 414c that calculates the position of the pixel corresponding to the scanning point of the light beam LB1 in real time based on the first reference pixel timing signal and the second reference pixel timing signal output from the adjustment unit 414b. ing.

  The reference pixel timing generation unit 414a generates a first reference pixel timing signal whose pulse width is sufficiently shorter than the driving voltage when the driving voltage of the first driving frequency rises, and generates the driving voltage of the second driving frequency. A second reference pixel timing signal whose pulse width is sufficiently shorter than the driving voltage is generated at the time of rising.

  The reference pixel timing adjustment unit 414b matches the first reference pixel timing signal generated by the reference pixel timing generation unit 414a with the timing of the horizontal reference position signal from the deflector 403. Of the second reference pixel timing signal so that the timing of the second reference pixel timing signal generated by the reference pixel timing generation unit 414a matches the timing of the vertical reference position signal from the deflector 403. Adjust the phase.

  By the way, the drive unit 413 generates a drive voltage of the first drive frequency applied between the second movable electrode 27 and the second fixed electrode 26 of the deflector 403 from the horizontal drive circuit and has a higher frequency than the drive voltage. A second voltage applied between the first movable electrode 22 and the first fixed electrode 12 of the deflector 403 from the vertical drive circuit while superimposing a first voltage (hereinafter, a voltage for specifying the horizontal reference position). A second voltage (voltage for specifying the vertical reference position) having a frequency higher than that of the drive voltage is superimposed on the drive voltage of the drive frequency. Here, the waveforms of the first voltage and the second voltage are preferably sine waves.

  Here, according to the change in the relative position (mechanical deflection angle) of the mirror part 24 with respect to the movable frame part 23, a change occurs in the capacitance between the second movable electrode 27 and the second fixed electrode 26, A minute change occurs in the current value (amplitude) based on the first voltage. This current value becomes the largest when the horizontal reference position, that is, the mechanical deflection angle is zero. From this, the reference pixel timing adjustment unit 414b monitors the current flowing through the pad 13c connected to the second fixed electrode 26, thereby obtaining a corresponding current value when the deflector 403 is at the horizontal reference position. It can be obtained as a horizontal reference position signal. Further, according to the change in the relative position (mechanical deflection angle) of the movable frame portion 23 with respect to the fixed frame portion 10, a change occurs in the capacitance between the first movable electrode 22 and the first fixed electrode 12, A minute change occurs in the current value (amplitude) based on the second reference position specifying voltage. From this, the reference pixel timing adjustment unit 414b monitors the current flowing through the pad 13b connected to the first fixed electrode 12, thereby obtaining a corresponding current value when the deflector 403 is at the vertical reference position. It can be obtained as a vertical reference position signal.

  The corresponding pixel calculation unit 414c uses the timing at which the first reference pixel timing signal and the second reference pixel timing signal output from the reference pixel timing adjustment unit 414b coincide with each other as the reference (center) pixel, and the light beam LB1 Identify the pixel being scanned. Here, the corresponding pixel calculation unit 414c specifies the position of the pixel based on the elapsed time from the time when the first reference pixel timing signal and the second reference pixel timing signal are simultaneously input, and the light beam LB1 The timing signal corresponding to each of the discrete scanning points 450 is output. The relationship between the elapsed time and the pixel may be calculated in advance and stored in the internal memory as a time table. The elapsed time described above may be measured using a counter. In this case, the counter is reset every time the first reference pixel timing signal and the second reference pixel timing signal are input simultaneously. What should I do?

  The timing management unit 414 described above may be configured by a microcomputer or the like, and by installing an appropriate program in the microcomputer, the reference pixel timing generation unit 414a, the reference pixel timing adjustment unit 414b, and the corresponding pixel calculation The part 414c can be realized. However, the timing management unit 414 is not limited to a microcomputer, and may be configured by a plurality of electronic components.

  By the way, the sensor device includes an optical axis OA1 (see FIG. 2) between the light source 401 and the deflector 403 and an optical axis OA2 (see FIG. 2) between the deflector 403 and the light detection unit 404. The mirrors 402 are matched.

  On the other hand, as shown in FIG. 7A, when the light beam LB1 is incident on the planar irradiated surface 410a, the light beam with respect to the irradiated surface 410a even when there is no object 406 in front of the irradiated surface 410a. The output of the light receiving element 404a of the light detection unit 404 differs depending on the incident angle of LB1. Here, when the light beam LB1 is repeatedly scanned in the vertical direction of FIG. 7A, the output of the light receiving element 404a fluctuates (fluctuates) as shown in FIG. 7B. Regarding the reflected light from the irradiated surface 410a, the regular reflection component (the solid arrow with the arrowhead on the right side in FIG. 7A indicates the regular reflection component, and the broken arrow with the arrowhead on the right side indicates the incident light and the reflected light. If the reflection component in the same direction is dominant, the intensity of the reflected light from the end of the irradiated surface 410a is weaker than the intensity of the reflected light from the central portion of the irradiated surface 410a. . That is, when the light beam LB1 enters the center of the irradiated surface 410a, the output of the light receiving element 404a reaches the maximum value in FIG. 7B, and when the light beam LB1 enters the end of the irradiated surface 410a. In addition, the output of the light receiving element 404a becomes the minimum value shown in FIG. In this case, the light beam LB1 is irradiated when the scanning point 450 is positioned approximately at the center in the vertical direction of the irradiated surface 410a when the deflection angle of the mirror 240 in the deflector 403 is 0, and when the deflection angle is maximum. A scanning point 450 is located at either end of the surface 410a in the vertical direction. Therefore, if the light beam LB1 is scanned as indicated by an arrow indicated by a one-dot chain line in FIG. 7A, the output of the light receiving element 404a changes as in a period of one cycle T in FIG. 7B. . Therefore, in order to detect the object 406 in the entire area of the irradiated surface 410a, it is necessary to distinguish between the reflected light from the end of the irradiated surface 410a and the reflected light from the object 406.

  On the other hand, in the sensor device according to the present embodiment, the signal processing unit 415 described above has discrete scanning points 450 of the light beam LB1 on the irradiated surface 410a when the object 406 is not present in the detection target space 405. Based on the timing signal corresponding to each, the output of the light detection unit 404 is stored in the memory 416 as a reference signal. Then, the signal processing unit 415 detects a reference signal stored in the memory 416 and a detection composed of an output of the light detection unit 404 based on the timing signal corresponding to each scanning point 450 after the reference signal is stored in the memory 416. An image generation unit 415b that generates an image having a difference from the signal as a pixel value for each scanning point 450, and an object extraction that extracts an object 406 existing in the detection target space 405 based on the image generated by the image generation unit 415b Part 415c.

  Therefore, for example, as shown in FIG. 8A, when the object 406 is present in front of the irradiated surface 410a, the object extraction unit 415c determines, for example, that the image generated by the image generation unit 415b is 2 By binarizing, a binarized image as shown in FIG. 8B is obtained, and an area that is equal to or less than the threshold is extracted as the object 406. In FIG. 8B, in the image generated by the image generation unit 415b, the pixel of the binarized image is black at a pixel whose pixel value is smaller than the threshold value (hatching is applied in FIG. 8B). In the image generated by the image generation unit 415b, the pixel of the binarized image is white in the pixel whose pixel value is equal to or greater than the threshold value. Therefore, a black area is extracted as an object 406 from such a binarized image.

  The sensor device of the present embodiment described above includes the light source 401 that emits the light beam, the deflector 403, the drive unit 413, the light detection unit 404, the timing management unit 414, the signal processing unit 415, and the like. Since the signal processing unit 415 includes the above-described image generation unit 415a and the object extraction unit 415b, the object 406 existing in front of the planar irradiated surface 410a can be accurately detected. It becomes possible.

  Therefore, for example, the signal processing unit 415 is associated in advance with the gesture recognition unit that recognizes a predetermined gesture based on the movement history of the object 406 extracted by the object extraction unit 415c and the gesture recognized by the gesture recognition unit. If a control unit that provides the control output to the control target device is provided, it is not necessary to go to the installation location and touch the control target device or the control switch of the control target device, thereby improving convenience.

  Further, in the sensor device, if the timing management unit 414 instructs the signal processing unit 415 to rewrite the reference signal of the memory 416 at each preset time, a decrease in detection accuracy due to disturbance is suppressed. It is possible to improve reliability.

  In the above-described sensor device, an operation unit (not shown) for instructing update of the reference signal is provided, and when the timing management unit 414 receives the instruction signal from the operation unit, the signal processing unit 415 stores the memory. The rewriting of the reference signal stored in 416 may be instructed. By adopting such a configuration, it is possible to more reliably suppress a decrease in detection accuracy due to disturbance, and reliability is improved.

  In addition, as described above, the sensor device of the present embodiment includes the optical axis OA1 (see FIG. 2) between the light source 401 and the deflector 403 and the optical axis OA2 between the deflector 403 and the light detection unit 404 (see FIG. 2). ) Is matched between the deflector 403 and the half mirror 402, the S / N ratio of the detection signal can be improved, and the reliability is improved.

  Further, in the sensor device of the present embodiment, the deflector 403 includes the outer frame portion 10 described above, the pair of first twisted spring portions 30, 30, the movable frame portion 23, and the pair of second twisted spring portions 25, 25, a mirror section 34, a first fixed electrode 12, a first movable electrode 22, a second fixed electrode 26, a second movable electrode 27, and the like. Since the drive circuit is provided, it is possible to increase the degree of freedom of setting each of the first drive frequency and the second drive frequency that are the drive frequencies of the deflector 403, and the detection target space 405 while achieving downsizing. (The deflection angle of the deflector 403 in each of the horizontal direction and the vertical direction can be increased).

  Incidentally, in addition to the light source 401 (hereinafter referred to as the detection light source 401) that emits the above-described light beam LB1 (hereinafter referred to as the detection light beam LB1), the sensor device has a configuration as shown in FIG. A light source 411 (hereinafter referred to as a display light source 411) that emits a light beam LB2 (hereinafter referred to as a display light beam LB2) for displaying a desired image may be provided on the irradiated surface 410a. In the configuration of FIG. 9A, the surface of the display unit 410 on which an image formed by two-dimensionally scanning the display light beam LB2 from the display light source 411 forms the irradiated surface 410a. is doing. As the display light source 411, a semiconductor laser that emits red light is used as the display light beam LB2, but the wavelength of the display light beam LB2 is not particularly limited.

  The sensor device further includes a dichroic mirror 412 positioned between the light source 401 for detection and the half mirror 402. The dichroic mirror 412 is optically designed to reflect the display light beam LB2 emitted from the display light source 411 to the half mirror 402 side and transmit the detection light beam LB1 from the detection light source 401.

  Here, the sensor device is configured such that the first optical axis between the display light source 411 and the deflector 403 and the second optical axis between the detection light source 401 and the deflector 403 are connected between the dichroic mirror 412 and the deflector 403. Are matched. Therefore, in this sensor device, most of the optical axes of both the optical system for displaying an image on the irradiated surface 410a and the optical system for detecting the object 406 can be aligned on the same axis. Compared to the case where separate optical paths are set in these optical systems, the optical path between the detection light beam LB1 and the display light beam LB2 in the detection target space 405 can be reduced in size and weight. Can be accurately matched.

  This sensor device includes a lens 407 positioned between the half mirror 402 and the light receiving element 404 a of the light detection unit 404. The lens 407 is a biconvex lens for condensing the detection light beam LB1 transmitted through the half mirror 402 onto the light receiving surface 404a of the light detection unit 404.

  In FIG. 9, the alternate long and short dash line in (a) indicates the optical axis, and the solid line arrow in (b) indicates that the detection light beam LB1 emitted from the detection light source 401 proceeds to the detection target space 405. The solid line arrow in (c) indicates the traveling path of the detection light beam LB1 reflected by the irradiated surface 410a, and the solid line arrow in (d) is emitted from the display light source 411. The traveling path of the light beam LB2 to the irradiated surface 410a is shown.

  In the sensor device described above, a predetermined image (for example, an image of a virtual switch 440 as shown in FIG. 10) can be displayed on the irradiated surface 410a of the display unit 410. In the sensor device, since the half mirror 402 is shared by the optical system for displaying an image on the irradiated surface 410a and the optical system for detecting the object 406, the number of parts can be reduced, and the size can be reduced. Weight reduction can be achieved.

  The above-described sensor device includes a housing (not shown) that houses the detection light source 401, the half mirror 402, the deflector 403, the light detection unit 404, the display light source 411, the dichroic mirror 412, the lens 407, and the like. ing.

  By the way, in the above-described sensor device, a part of the detection light beam LB1 is scattered by the half mirror 402, the deflector 403 or the like, or reflected by the inner surface of the housing, so that the light receiving surface 404a of the light detection unit 404 is obtained. There is a concern that the S / N ratio of the output of the light detection unit 404 may be reduced.

  Therefore, the sensor device preferably includes a light blocking member (not shown) that is disposed around the optical path of the detection light beam LB1 and the display light beam LB2 and blocks stray light. In the sensor device, by providing the light blocking member, stray light reaching the light detection unit 404 can be reduced, and the S / N ratio of the output of the light detection unit 404 can be improved. Although the light shielding member is formed of a black resin molded product, it is only necessary to block stray light, and the material and forming method of the light shielding member are not particularly limited. In the sensor device, the inner surface of the housing is preferably a rough surface that scatters stray light. Accordingly, the sensor device can reduce stray light that reaches the light receiving surface 404a of the light detection unit 404. As a processing method for making the inner surface of the housing rough, for example, there is blasting. The means for reducing the stray light that enters the inner surface of the housing and reaches the light receiving surface 404a of the light detection unit 404 is not limited to the example in which the inner surface of the housing is a rough surface. For example, when the material of the housing is metal, the inner surface of the housing may be painted with a black coating material, or black anodized may be formed.

  For example, as shown in FIG. 10, the sensor device having the configuration shown in FIG. 9 has a display unit 410 installed near a door 470 on an indoor wall surface 460, and an external device (for example, a lighting fixture, An image of a virtual switch (hereinafter referred to as a virtual switch) 440 for on / off control of an air conditioner, a television, etc.) can be displayed, and the presence or absence of an object 406 at an arbitrary position in the detection target space 405 can be detected. It becomes possible to do. In the example of FIG. 10, in the image of the virtual switch 440, there is a case where the object 406 is at the position of the virtual first switch element 441 composed of a square image on the left side of the character “ON”, and the character “OFF” The signal processing unit 415 may be provided with a determination unit that determines, based on the output of the object extraction unit 415b, the case where the object 406 is present at the position of the virtual second switch element 442 made of the left square image. Therefore, in accordance with the determination result of the determination unit, a transmission unit that transmits to the external device a remote control signal for on / off control of a switch inserted between the external device and a power source that supplies power to the external device If an antenna (such as an antenna) is provided, an embedding hole for embedding an embedding type switch, which is a kind of embedding type wiring apparatus, can be formed in a construction material such as an indoor wall, The virtual switch 440 can be provided by installing the display unit 410 on the wall surface 460 formed of the surface of the construction material without providing the preceding wiring for constructing the wiring device on the back of the wall or the like. In installing the display unit 410 on the construction material, for example, the display unit 410 may be attached to the construction material with a pressure-sensitive adhesive or the like previously provided on the back surface side.

Further, the arrangement of the detection light source 401, the display light source 401, the light detection unit 404, and the like is shown in FIG.
The arrangement shown in FIG. 11A is not limited to this example. 11A and 11B, the alternate long and short dash line in FIG. 11A indicates the optical axis, and the solid line arrow in FIG. 11B indicates that the detection light beam LB1 emitted from the detection light source 401 travels to the detection target space 405. The solid line arrow in (c) indicates the traveling path of the detection light beam LB1 reflected by the irradiated surface 410a, and the solid line arrow in (d) is emitted from the display light source 411. The traveling path of the light beam LB2 to the irradiated surface 410a is shown. Further, the object 406 is not particularly limited to the finger of a human hand.

DESCRIPTION OF SYMBOLS 10 Outer frame part 12 1st fixed electrode 21 Mirror surface 22 1st movable electrode 23 Movable frame part 24 Mirror part 26 2nd fixed electrode 27 2nd movable electrode 401 Light source 402 Half mirror 403 Deflector 404 Photodetection part 405 Detection target space 406 Object 410a Irradiated surface 413 Drive unit 414 Timing management unit 415 Signal processing unit 415a Image generation unit 415b Object extraction unit 416 Memory 450 Scanning point LB1 Light beam

Claims (5)

  A light source that emits a light beam, and the light beam emitted from the light source can be reflected two-dimensionally on a planar irradiated surface in the detection target space by reflecting the light beam to the detection target space side. A deflector, a drive unit for generating a drive signal for driving the deflector, and the light beam reflected by the deflector and reflected on the detection target space side to generate an output corresponding to the amount of received light. A light detection unit; a timing management unit that outputs a timing signal at a timing corresponding to each of the discrete scanning points of the light beam on the irradiated surface based on the drive signal; and the light based on the timing signal. A signal processing unit that performs signal processing on the output of the detection unit; and a memory that can store the output of the light detection unit; and the signal processing unit includes the irradiated surface when no object is present in the detection target space. Based on the timing signal corresponding to each of the discrete scanning points of the light beam, the output of the light detection unit is stored in the memory as a reference signal, and the reference signal and the reference signal stored in the memory Image generation for generating an image with a difference between a detection signal composed of an output of the light detection unit based on the timing signal corresponding to each of the scanning points after the image is stored in the memory as a pixel value for each scanning point And an object extraction unit that extracts the object existing in the detection target space based on the image generated by the image generation unit.   The sensor device according to claim 1, wherein the timing management unit instructs the signal processing unit to rewrite the reference signal of the memory at each preset time.   An operation unit for instructing to update the reference signal is provided, and the timing management unit rewrites the reference signal stored in the memory with respect to the signal processing unit when receiving the instruction signal from the operation unit. The sensor device according to claim 1, wherein:   The deflector includes an outer frame portion, a movable frame portion disposed inside the outer frame portion and supported by the outer frame portion via a pair of first twisted spring portions, and an inner side of the movable frame portion. A mirror surface is formed which is supported by the movable frame portion and reflects the light beam via a pair of second twisted springs arranged in a direction perpendicular to the parallel direction of the first twisted springs. A mirror portion, a first fixed electrode provided on the movable frame portion side in the outer frame portion, a first movable electrode provided on the outer frame portion side in the movable frame portion, and the movable A second fixed electrode provided on the mirror part side in the frame part; and a second movable electrode provided on the movable frame part side in the mirror part; and The first drive frequency is applied to one of the first movable electrode and the first fixed electrode and between the second movable electrode and the second fixed electrode so that the scanning line is scanned in the horizontal direction. A horizontal driving circuit for applying a driving voltage; and between the first movable electrode and the first fixed electrode, and the second movable electrode and the second fixed electrode so that the light beam is scanned in a vertical direction. 4. The sensor device according to claim 1, further comprising: a vertical drive circuit that applies a drive voltage having a second drive frequency to the other side of the gap. 5.   A half mirror that reflects and transmits the light beam between the light source and the deflector, and an optical axis between the light source and the deflector, and an optical axis between the deflector and the light detection unit, The sensor device according to any one of claims 1 to 4, wherein the deflector and the half mirror are made to coincide with each other.

Images