JP2005337907A - Optical sensor and actuator using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical sensor which detects the two-dimensional moving position of a light beam extensively and with high precision. <P>SOLUTION: The optical sensor 38 comprises a light source 10 and a light receiving element 24 which receives a light beam from the light source 10 to detect the two dimensional moving position of an incident light beam on the basis of an output of the light receiving element 24. A light receiving area 30 of the light receiving element 24 is divided into a first area A and a second area B by a first division line 40 which is parallel to a first direction X. Either one of the first area A or the second area B is divided by a second division line 42 which is inclined with respect to the first division line 40. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an objective lens actuator used in an information recording / reproducing apparatus for recording and / or reproducing information with respect to an optical recording medium such as a magneto-optical disc, a write-once disc, and a DVD, and an optical deflector for optical communication. The present invention relates to an optical sensor suitable for detecting the position and / or inclination of a movable part, such as a galvano mirror used in an optical device, a moving stage used in a linear stage, etc., and an actuator using the same. .

  In an objective lens actuator that drives an objective lens such as an information recording / reproducing device in the focus direction and / or tracking direction, a galvano mirror that tilts the mirror to control deflection of reflected light, a moving stage, etc., the position and tilt of the movable part A sensor is used to detect the light or to control the driving of the movable part, and a highly accurate and non-contact optical sensor is often used as the sensor.

  As an actuator using the conventional optical sensor, for example, a tilt sensor device as shown in FIG. 19 is known (see, for example, Patent Document 1).

  In this tilt sensor device, an optical disk 101 is placed on a turntable 102 and rotated by a spindle motor 103, and a laser beam for recording or reproduction is transmitted between an upper substrate 101a and a lower substrate 101b of the optical disk 101 by an objective lens 105. In an optical pickup that records or reproduces information by focusing on the signal surface 101c, the inclination of the recording surface 101c with respect to the optical axis of the objective lens 105 is detected and the direction of the optical axis of the objective lens 105 is adjusted. Is.

  In FIG. 19, a main laser beam ML for recording or reproduction having a wavelength of 405 nm emitted from the main laser light emitting diode 111 is collimated by the collimator lens 112, then passes through the half mirror 113, and further passes through the dichroic mirror 114. The light is transmitted, reflected by the rising mirror 115, and condensed on the recording surface 101 c of the optical disk 101 by the objective lens 105.

  The objective lens 105 can be driven in the focus direction by a focus actuator or the like (not shown), and can be driven by the tilt actuator 120 so as to adjust the inclination of the optical axis in the radial direction and the tangential direction of the optical disc 101. Yes.

  The return main laser beam ML ′ reflected by the recording surface 101 c of the optical disk 101 is reflected by the rising mirror 115 through the objective lens 105, then passes through the dichroic mirror 114, and is further reflected by the half mirror 113 to be condensed. The light is condensed on the divided photodetector 122 by the lens 121, and an RF signal, a focus error signal, and the like are detected based on the output.

  On the other hand, the sub laser beam SL having a wavelength of 650 nm emitted from the sub laser light emitting diode 125 is converted into parallel light by the collimator lens 126, reflected by the half mirror 127, reflected by the dichroic mirror 114, and further raised by the rising mirror 115. And is focused on the recording surface 101c of the optical disc 101 in a defocused state by the objective lens 105.

  The return sub-laser beam SL ′ reflected by the recording surface 101 c of the optical disk 101 is reflected by the rising mirror 115 through the objective lens 105, then reflected by the dichroic mirror 114, and further transmitted through the half mirror 126 and condensed. The light is condensed on the quadrant photodetector 129 by the lens 128, and based on the output, the optical disc tilt detection signal generator 130 detects the tilt in the radial direction and the tangential direction of the recording surface 101c with respect to the optical axis of the objective lens 105, Based on those tilt signals, the tilt control unit 131 drives the objective lens 105 via the tilt actuator 120 so that the tilt of the optical axis of the objective lens 105 in the radial direction and the tangential direction of the optical disc 101 is adjusted. Become That.

  As an actuator using a conventional optical sensor, for example, a position detector as shown in FIG. 20 is also known (see, for example, Patent Document 2).

  This position detector detects the position of the objective lens in the tracking direction Tr in the optical pickup device, and the objective lens (not shown) is displaceable in the focus direction Fo via the focus spring 141 on the rotating plate 142. The rotating plate 142 is supported by an actuator base (not shown) so as to be displaceable in the tracking direction Tr by a rotating shaft 143.

A light emitting element 144 is attached to the rotating plate 142, and a light receiving element 146 is attached to the actuator base so as to receive the emitted light 145 from the light emitting element 144. The light receiving element 146 includes light receiving portions 149a and 149b divided by a dividing line 148 inclined with respect to the direction 147 in which the optical axis of the emitted light 145 of the light emitting element 144 moves by tracking, and these light receiving portions 149a. , 149b based on the output difference, the position of the objective lens in the tracking direction Tr is detected.
JP 2002-334464 A Japanese Patent Laid-Open No. 5-210863

  However, in the tilt sensor device disclosed in Patent Document 1, the detection range is maximum even though the tilt in the radial direction and the tangential direction of the recording surface 101c with respect to the optical axis of the objective lens 105 can be detected. However, the diameter is up to the diameter of the return sub-laser beam SL ′ on the light receiving surface of the quadrant photodetector 129.

  For this reason, if the diameter of the return sub-laser beam SL ′ on the light receiving surface of the four-divided photodetector 129 is reduced, the detection range becomes narrow, and the inclination cannot be detected over a wide range. When the diameter of ′ is increased, there is a problem that even if the detection range can be widened, the quadrant photodetector 129 is increased, resulting in an increase in the size of the optical pickup.

  In the position detector disclosed in Patent Document 2, the dividing line 148 of the light receiving element 146 is inclined with respect to the moving direction 147 of the optical axis of the emitted light 145 by tracking. Compared with the case where 148 is orthogonal to the moving direction 147, the range in which the emitted light 145 from the light emitting element 144 intersects the dividing line 148 is widened by tracking, and the position of the objective lens in the tracking direction Tr is extended over a wide range. Can be detected.

  However, since this position detector can detect only the moving position of the outgoing light 145 incident on the light receiving element 146 in one direction, it cannot be applied to the case of detecting the position in the two-dimensional direction. Note that there are two-dimensional PSDs (position detection elements) (for example, S5990 manufactured by Hamamatsu Photonics Co., Ltd.) as a means for detecting the position of the incident light beam in the two-dimensional direction. This two-dimensional PSD is compared with the one-dimensional PSD. Since the position detection distortion of the light receiving surface is large and the position detection error is large, highly accurate position detection is difficult.

  Accordingly, an object of the present invention made in view of the above circumstances is to provide an optical sensor capable of detecting a movement position of a light beam in a two-dimensional direction over a wide range and with high accuracy, and an actuator using the same.

The invention according to claim 1, which achieves the above object, includes a light source and a light receiving element that receives a light beam from the light source, and moves the incident light beam in a two-dimensional direction based on an output of the light receiving element. In the optical sensor that detects the position,
The light receiving region of the light receiving element includes a first region and a second region divided by a first dividing line parallel to a first direction, and at least of the first region and the second region One is divided by a second dividing line inclined with respect to the first dividing line.

  According to a second aspect of the present invention, in the optical sensor according to the first aspect, the position of the light beam in the first direction and a second direction perpendicular to the first direction based on the output of the light receiving region. It is characterized by outputting information related to.

  The invention according to claim 3 relates to the position of the light beam in the first direction based on an output difference between at least two regions divided by the second dividing line in the optical sensor according to claim 2. The information related to the position of the light beam in the second direction is output based on the output difference between the first region and the second region.

The invention according to claim 4 includes a light source and a light receiving element that receives a light beam from the light source, and detects the moving position of the incident light beam in a two-dimensional direction based on the output of the light receiving element. In the sensor
The light receiving area of the light receiving element includes a first area, a second area, and a third area divided by two first dividing lines parallel to the first direction, and the second area at the center. The region is divided by a second dividing line inclined with respect to the first dividing line.

  According to a fifth aspect of the present invention, in the optical sensor according to the fourth aspect, the position of the light beam in the first direction and a second direction perpendicular to the first direction based on the output of the light receiving region. It is characterized by outputting information related to.

  According to a sixth aspect of the present invention, in the optical sensor according to the fifth aspect, in the first direction based on an output difference between at least two regions of the second region divided by the second dividing line. Outputs information related to the position of the light beam, and determines the position of the light beam in the second direction based on the output difference between the first area and the third area located on both sides of the second area. It is characterized by outputting related information.

The invention according to claim 7 is a light having a light source and a light receiving element that receives a light beam from the light source, and detecting a moving position in a two-dimensional direction of the incident light beam based on an output of the light receiving element. In the sensor
The light receiving region of the light receiving element includes a first region, a second region, and a third region divided by two first dividing lines parallel to the first direction,
Outputs information related to the position of the light beam in a second direction substantially orthogonal to the first direction based on the outputs of the first region and the third region located on both sides of the second region. Then, information related to the position of the light beam in the first direction is output based on the output of the second region.

  According to an eighth aspect of the present invention, in the optical sensor according to the seventh aspect, the second region includes a position detection element.

  The invention according to claim 9 is the optical sensor according to claim 7 or 8, wherein the first region and the third region are formed of a photodiode.

  The invention according to claim 10 is the optical sensor according to any one of claims 2, 3, 5 to 9, wherein the position detection range of the light beam in the first direction is light in the second direction. It is characterized by being larger than the position detection range of the beam.

  According to an eleventh aspect of the present invention, in the optical sensor according to any one of the second, third, and fifth to tenth aspects, the spot of the light beam incident on the light receiving region is the first direction than the first direction. The second direction is a large shape.

  Furthermore, the invention of an actuator according to a twelfth aspect that achieves the above object comprises a movable portion that is movable with respect to the fixed portion, and a position and / or an inclination amount of the movable portion. And an optical sensor described in the item.

  The invention according to claim 13 is the actuator according to claim 12, wherein the movable portion has at least an optical element.

  The invention according to claim 14 is the actuator according to claim 13, wherein the optical element is a mirror.

  According to a fifteenth aspect of the present invention, in the actuator according to the thirteenth or fourteenth aspect, a part of the optical sensor is disposed on the movable portion on a side opposite to the optical element with respect to the center of gravity of the movable portion. It is characterized by being.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to provide the optical sensor which can detect the movement position of the two-dimensional direction of a light beam in a wide range and with high precision, an actuator using it can be provided.

  Embodiments of the present invention will be described below with reference to FIGS.

(First embodiment)
1 to 13 show a first embodiment of the present invention. The present embodiment shows a galvanometer mirror 1 as an actuator used in a two-dimensional laser scanner. FIG. 1 is a perspective view of the galvanometer mirror 1 seen from the front obliquely above the mirror 3, and FIG. 3 is an exploded perspective view of the entire galvano mirror 1, FIG. 4 is an exploded perspective view of the movable portion 2, and FIG. 5 is an X− view through the rotation center G of the mirror 3. FIG. 6 is a cross-sectional perspective view taken along the YZ plane that also passes through the center of rotation G, and FIG. 7 is a state in which the movable portion 2 is rotated about the Y axis from the state shown in FIG. FIG. 8 is a perspective view showing the driving means, FIGS. 9A and 9B are plan views showing the driving means, FIG. 10 is an exploded perspective view of the LED unit 9, and FIG. FIG. 12 shows a light receiving region of the light receiving element 24. Diagram illustrating the configuration of a 0, FIGS. 13 (A), (B) is a diagram showing the detection characteristics of the X-direction position Sx and the Y-direction position Sy by the light sensor 38.

  The galvanometer mirror 1 of the present embodiment has one mirror 3, and has a planar reflecting surface 3a on the surface thereof. As shown in FIG. 1, the mirror 3 is configured to be tiltable in two directions: a θx direction around the X axis that is the horizontal direction, and a θy direction that is around the Y axis that is perpendicular to the horizontal direction. The X axis and the Y axis pass through the rotation center G of inclination. The direction perpendicular to the reflecting surface 3a is taken as the Z axis.

  The galvanometer mirror 1 reflects light 34 emitted from a laser 31, which is an external light source, and converted into parallel light by a collimator lens 32, by the reflecting surface 3 a, and projects the reflected light 34 a onto a flat screen 33. The reflective surface 3a is tilted in the θx direction to move the reflected light 34a in the Y2 direction, which is the vertical direction on the screen 33, and the reflective surface 3a is tilted in the θy direction to cause the reflected light 34a to move in the horizontal direction on the screen 33. The reflected light 34a is controlled to be tilted in two directions by moving in the X2 direction, and the light projected on the screen 33 is controlled to move in two directions.

  First, the configuration of the galvanometer mirror 1 will be described in the order of assembly.

  The holder 4 for holding the mirror 3 is made of magnesium die cast in order to reduce the rigidity and weight, and coil fixing surfaces 4b substantially parallel to the XZ plane are formed on both sides in the Y direction. The EL coil 7 wound in the shape of a square frame on the coil fixing surface 4b is positioned and bonded and fixed inside by the projection 4c. On the EL coil 7, an AZ coil 8 wound in a shape in which a fan-shaped central portion is cut is positioned and bonded and fixed inside by the projection 4d.

  The holder 4 is formed with a pivot mounting portion 4e at the center in the Z (−) direction, and one end of the pivot 6 is bonded and fixed to the pivot mounting portion 4e. The pivot 6 has a substantially drum-shaped bent portion 6a formed at the center thereof, and a stainless steel wire 13 for springs is provided at the center so as to protrude from the pivot 6 at its center. ) Direction one end 13a is inserted into the hole 4f of the holder 4 and bonded when the pivot 6 is bonded and fixed to the pivot mounting portion 4e. The pivot 6 is molded by thermosetting silicone rubber using a mold, and at the time of molding, a wire 13 having a diameter of approximately 1/10 of the diameter of the bent portion 6a is insert-molded at the center of the pivot 6. The In the present embodiment, the diameter of the bent portion 6a of the pivot 6 is 1 mm, and the diameter of the wire 13 is 0.1 mm.

  The mirror 3 is formed by applying a reflective coating of gold or a dielectric multilayer film constituting the reflective surface 3a on the surface of the silicon wafer, and then cutting it into a rectangular shape and attaching it to the Z (+) side of the holder 4 It is bonded and fixed to the attachment surface 4a with a silicon-based adhesive.

  The holder 4 is formed with a flexible attachment portion 4g at the central portion in the Z (−) direction, and a rectangular frame-shaped attachment portion 5a located at the central portion of the flexible substrate 5 is bonded to the flexible attachment portion 4g. . The mounting portion 5a is provided with a soldering land (not shown), and the terminals of a total of two EL coils 7 and a total of four AZ coils 8 are soldered to the soldering land. The flexible substrate 5 is formed with two fixing portions 5c on both sides thereof. The attachment portion 5a and the fixing portion 5c are four connecting portions having a bent shape as shown in FIG. Connected at 5b.

  The base 21, which is a fixed portion that supports the holder 4, is made of the same magnesium die cast as the holder 4 and is formed in a substantially square frame shape. A flat yoke 28 made of an iron plate is bonded to the inner wall of both ends of the Y direction in the base 21, and a magnet 27 is bonded to the surface of the yoke 28.

  As shown in FIG. 3, the magnet 27 is magnetized with its surface divided into two in the Z direction. The two magnets 27 that face each other in the Y direction are disposed so that the different polar surfaces face each other and face the corresponding AZ coil 8 with a gap.

  The base 21 is provided with a bar 21b at the center by connecting walls on both sides, and the holder 4 is assembled to the bar 21b. That is, the holder 4 is assembled so that the bar 21b is positioned between the four spaced apart posts 4h protruding in the Z (−) direction of the holder 4, and one end of the pivot 6 in the Z (−) direction is In this case, one end 13a in the Z (−) direction of the wire 13 is also inserted into and bonded to the hole 21d formed in the bar 21b. Further, the fixing portion 5 c of the flexible substrate 5 is bonded and fixed to the flexible fixing portion 21 e of the base 21.

  The LED unit 9 constituting the optical sensor 38 is held on the four posts 4 h of the holder 4. The LED unit 9 has a copper balancer 12, and a substrate 11 with four cut corners is attached to the balancer 12, and an infrared light beam having a wavelength of 900 nm, which is a light source, is emitted to the substrate 11. LED 10 to be soldered. In addition, the balancer 12 is formed with a stop 12a for shaping the cross-sectional shape of the light beam emitted from the LED 10 at the center thereof. The diaphragm 12a has an elliptical shape whose size in the Y direction is twice as large as that in the X direction. Moreover, the board | substrate 11 and the attaching part 5a of the flexible substrate 5 are electrically connected by the lead wire which is not shown in figure.

  The LED unit 9 is held by adhering and fixing the four corners of the balancer 12 to the four posts 4 h of the holder 4, whereby the bar 21 b provided on the base 21 is connected to the four posts 4 h of the holder 4 and the LED unit 9. It is located with a gap in the space surrounded by.

  The holder 4, the mirror 3, the EL coil 7, the AZ coil 8, the LED unit 9, the attachment portion 5 a of the flexible substrate 5, and one end of the pivot 6 constitute the movable portion 2. Tilt is moved in two directions.

  Further, the substrate unit 22 is fixed to the surface of the base 21 in the Z (−) direction by four screws 35. A substrate 23 is provided on the substrate unit 22, and a light receiving element 24 that constitutes a light sensor 38 together with the LED unit 9 is soldered to a surface facing the LED unit 9, and a light receiving element is disposed on the opposite surface thereof. Electrical circuits 25 such as 24 preamplifiers, drive circuits for the EL coil 7 and AZ coil 8, and drive circuits for the LEDs 10, and a connector 26 are arranged. The substrate 23 is electrically connected to the fixed portion 5c of the flexible substrate 5 via a cable (not shown). The light receiving element 24 includes a silicon PIN photodiode having a light receiving region 30 divided on a silicon substrate.

  Hereinafter, the movable part 2 will be described in more detail.

  As described above, the movable portion 2 is supported by the base 21 so as to be tiltable in two directions by the pivot 6 and the thin metal wire 13. The pivot 6 has a bend 6a at the center of the pivot 6 so that it can be easily tilted and deformed in the θx and θy directions around the rotation center G, and the wire 13 is inserted in the center of the pivot 6. . The center of gravity of the movable part 2 is made to coincide with the rotation center G, and the inertia main axis of the movable part 2 is made to coincide with the X axis and the Y axis. Therefore, when the movable part 2 is driven to tilt, unnecessary resonance hardly occurs.

  Here, the spring constant of bending of the pivot 6 is proportional to the cross-sectional secondary moment and Young's modulus, and the cross-sectional secondary moment is proportional to the fourth power of the radius of the circular cross section. Further, the spring constant in the Z direction in which the pivot 6 extends is proportional to the Young's modulus and the cross-sectional area (the square of the radius of the circular cross section). In the present embodiment, since the diameter of the wire 13 is approximately 1/10 of the diameter of the bent portion 6a, the spring constant of elongation in the Z direction can be made higher than the increase of the spring constant in the θx and θy directions. it can. Accordingly, since the resonance frequency at which the movable part 2 vibrates in the Z direction can be increased, the amount of vibration in the Z direction of the movable part 2 when the vibration in the Z direction is applied to the galvano mirror 1 from the outside can be reduced, and stable tilt control characteristics can be achieved. Can be obtained.

  As shown in FIG. 8, the magnet 27 has a magnetic pole surface that is divided into two in the Z direction, and is disposed opposite to the AZ coil 8 with a gap therebetween. The two magnets 27 facing in the Y-axis direction are It is arranged so that different polar faces face each other. Further, the AZ coil 8 is wound in a shape in which a fan-shaped central portion is cut, and the two oblique effective sides 8 a thereof are positioned so as to face the two magnetic poles of the magnet 27, respectively. The EL coil 7 is also positioned so that the two effective sides 7 a face the two magnetic poles of the magnet 27.

  A total of four AZ coils 8 and two EL coils 7 are supplied with current from the power supply outside the galvanomirror 1 through the connector 26, the substrate 23, a cable (not shown), and the flexible substrate 5 according to the tilting direction. For example, as shown in FIG. 8, when the movable part 2 is tilted in the θx direction, a current is supplied so that a force Fx is generated at the effective sides 7a of the two EL coils 7. Further, when the movable part 2 is tilted in the θy direction, a current is supplied so that a force Fy is generated at the effective sides 8a of the four AZ coils 8. The EL coil 7, the AZ coil 8, the magnet 27 and the yoke 28 constitute driving means for tilting the movable part 2 in two directions.

  In the present embodiment, the range in which the movable part 2 tilts is ± 20 degrees in θymax and ± 5 degrees in θxmax, and θymax is remarkably larger than θxmax.

  Here, in a normal galvanometer mirror, the driving means is divided into a movable part side and a fixed part side, for example, a coil is arranged on the movable part side and a magnet is arranged on the fixed part side, or a moving coil type is used. A moving magnet type is provided by arranging a magnet on the movable part side and a coil on the fixed part side. For this reason, it is necessary to increase the interval between the coil and the magnet so that they do not interfere with each other. As a result, the magnetic field acting on the coil decreases, the drive sensitivity of the movable part decreases, and the galvanometer mirror becomes large. There was a problem of becoming.

  On the other hand, in the present embodiment, the AZ coil 8 and the EL coil 7 are arranged only in one axial direction of the two rotation axes X-axis and Y-axis with respect to the rotation center G of the movable portion 2. Further, they are arranged apart from each other in the extending direction of the Y axis, which is a rotation axis having a large tilt angle. The EL coil 7, the AZ coil 8, and the magnet 27 are all flat and are arranged in parallel with each other on an XZ plane that is a plane perpendicular to the Y axis that is a rotation axis having a large tilt angle. Therefore, even if the movable part 2 is tilted around the Y axis having a large tilt angle, the minimum distance D (see FIG. 6) in the Y axis direction between the EL coil 7 and the AZ coil 8 and the magnet 27 does not change. D need not be widened due to the slope of θy. Further, the EL coil 7 and the AZ coil 8 change from a state parallel to the magnet 27 to a non-parallel state, and the force generated in the EL coil 7 and the AZ coil 8 becomes non-uniform, causing unnecessary resonance. There is nothing.

  Since the minimum distance D increases and decreases when the movable part 2 is tilted around the X axis, it is sufficient to determine only the inclination of θx. In the present embodiment, since θxmax is set to ¼ of θymax, the minimum distance D does not need to be so large. Accordingly, since the magnetic field acting on the EL coil 7 and the AZ coil 8 can be increased, the driving sensitivity can be increased, and the galvanometer mirror 1 can be reduced in size.

  Further, as shown in detail in FIG. 9A, the AZ coil 8 has a shape obtained by cutting the central part of the fan shape, and its effective side 8a is an oblique straight line of θymax passing through the rotation center G. It is located away from P1 by D2 outside the rotation range. Therefore, as shown in FIG. 9B, even when the movable part 2 is inclined by θymax, one effective side 8a is parallel to the magnetic pole boundary 27b of the magnet 27 and is not positioned on the opposite magnetic pole surface. Thus, by making the effective side 8a of the AZ coil 8 approximately equal to or slightly larger than the maximum value of the rotation angle of the movable part 2, a stable magnetic field can be applied to the effective side 8a. .

  Further, since the base 21 is formed with large notches 21f that reach the rotation center G on both walls in the X direction, even when the movable part 2 is greatly inclined in the θy direction, the movable part 2 and the reflecting surface Incident light or reflected light with respect to 3 a does not interfere with the X-direction wall of the base 21. Further, the driving means of the movable part 2 composed of the EL coil 7, the AZ coil 8, the magnet 27, and the yoke 28 is not arranged in the X direction that is largely inclined with respect to the movable part 2, but is arranged in the Y direction with a small inclination. Has been. Therefore, the driving means can be easily configured so as not to interfere with the components fixed to the movable portion 2 and the base 21 and the incident light or reflected light with respect to the reflecting surface 3a.

  Further, since the LED unit 9 is disposed on the side opposite to the mirror 3 with respect to the rotation center G, the LED unit 9 can be used as a counter balance of the mirror 3. Therefore, the center of gravity of the movable part 2 can be easily matched with the rotation center G without adding another part for balancing, so that the configuration can be simplified and the moment of inertia of rotation can be reduced. , Driving sensitivity can be increased.

  Next, the optical sensor 38 will be described in more detail.

  As described above, the optical sensor 38 includes the LED unit 9 held by the movable portion 2 and the light receiving element 24 arranged on the fixed-side substrate 23. The LED 10 of the LED unit 9 is supplied with a current from a power supply external to the galvano mirror 1 via the connector 26, the substrate 23, a cable (not shown), the flexible substrate 5, and a lead wire (not shown), and the light emitted from the LED 10 The beam is shaped into an elliptical light beam by the elliptical aperture 12 a and projected as an elliptical spot 29 onto the light receiving region 30 of the light receiving element 24.

  As shown in detail in FIG. 12, the light receiving region 30 is divided into eight wedges in the Y direction, and eight regions B4, B3, B2, B1, A1, A2, A3, and A4 from the Y-side. have. In other words, the light receiving region 30 includes a first region A composed of A1, A2, A3 and A4 in the Y direction and a second region B composed of B4, B3, B2 and B1 in the X direction. The first area A and the second area B are each divided into two by a dividing line 41 parallel to the X direction, and further divided into two by a parallel first dividing line 40 and arranged in the Y direction. These regions are divided into a total of eight regions by a second dividing line 42 oblique to the X and Y directions.

  In the present embodiment, the light receiving region 30 is divided into a length of 1 mm by three dividing lines 40, 41, 41 with the X direction being 9 mm and the Y direction being 4 mm in total length. The elliptical spot 29 is 2 mm in the Y direction and 1 mm in the X direction. Therefore, even if the spot 29 moves ± 4 mm in the X direction and ± 1 mm in the Y direction on the light receiving area 30, the spot 29 does not protrude from the light receiving area 30.

  FIG. 7 shows a state in which the movable portion 2 is inclined by θy about the rotation center G around the Y axis from the state shown in FIG. At this time, since the LED unit 9 also tilts around the Y axis and moves in the X direction, the spot 29 on the light receiving region 30 also moves parallel to the X direction. Similarly, when the movable portion 2 is tilted by θx around the rotation center G around the X axis, the LED unit 9 is also tilted around the X axis and moved in the Y direction. Move parallel to Y direction.

  In FIG. 12, when the spot 29a is located at the center of the light receiving region 30, when the spot 29b is moved by 1 mm from the central position in the Y direction, and when the spot 29c is moved by 4 mm from the central position in the X direction. It shows a case where the spot 29d is located by moving 4 mm in the X direction and 1 mm in the Y direction from the center position. Actually, when the movable part 2 is tilted, the distance between the LED unit 9 and the light receiving region 30 is increased, and light is projected obliquely to the light receiving region 30, so the spots 29b, 29c, 29d are Although the major axis and / or the minor axis become larger than the spot 29a and cause distortion, it is simplified in the figure.

  The current output from the eight divided regions of the light receiving region 30 is I / V converted by a preamplifier, and the following calculation is performed based on the voltage, thereby normalizing the spot 29 with respect to the light receiving region 30 in the X direction. Information related to the position Sx and the position Sy in the Y direction, that is, the inclination angle of the movable part 2 in two directions can be obtained.

Sx = ((A3 + A1 + B2 + B4) − (A4 + A2 + B1 + B3)) / (A1 + A2 + A3 + A4 + B1 + B2 + B3 + B4)
Sy = ((A1 + A2 + A3 + A4) − (B1 + B2 + B3 + B4)) / (A1 + A2 + A3 + A4 + B1 + B2 + B3 + B4)

  FIG. 13A shows an example of Sx when the spot 29 moves in the X direction at the position Y = 0 mm, and FIG. 13B shows the spot 29 at the positions X = 0 and X = 4 mm. Shows an example of Sy when is moved in the Y direction. From FIG. 13A, it can be seen that a position information signal Sx with good linearity can be obtained up to X = 4 mm. In addition, it can be seen from FIG. 13B that a position information signal Sy with substantially good linearity can be obtained up to Y = 2 mm.

  By configuring the light receiving region 30 as described above, the position Sx in the X direction is parallel to the X direction even if the detection range in the X direction is significantly larger than ± 4 mm with respect to the detection range in the Y direction ± 1 mm. It can be detected by the difference between the areas divided by the first dividing line 40 and the dividing lines 41 and 41 and the second dividing line 42 oblique to the X direction and the Y direction. Sy can be detected by the difference between the first region A and the second region B that are divided in the Y direction by the first dividing line 40. Therefore, for example, when the light receiving area is a simple two-divided area and a detection range of ± 4 mm is obtained, the diameter of the light spot needs to be 8 mm and the length of the light receiving area is 16 mm. Since it can be about half of 9 mm, the light receiving element 24 can be reduced in size, and the distortion of the light spot projected on the light receiving region 30 when the movable portion 2 is tilted can be reduced.

  Furthermore, in this embodiment, since the spot 29 on the light receiving region 30 is made smaller in the X direction where the detection range is large compared to the Y direction, the size of the light receiving region 30 can be further reduced. In other words, the position Sy in the Y direction is detected by the difference between the two divided areas of the first area A and the second area B divided by the first dividing line 40 perpendicular to the direction in which the spot 29 moves. Therefore, the length in the Y direction of the spot 29 cannot be made smaller than the detection range, but the position Sx in the X direction is detected using the region divided by the oblique second dividing line 42. It can be shorter than the detection range.

In the present embodiment, the light receiving region 30 is divided into four regions in the Y direction by the first dividing line 40 and the dividing lines 41 and 41 parallel to the X direction, and further, the oblique second dividing line 42 is used. Although each of them is divided into two, the dividing method is not limited to this. For example, it may be divided into two regions in the Y direction by a dividing line parallel to the X direction, or may be divided into six or more regions. Further, it is not necessary to divide all the regions by the second dividing line 42. For example, A3 and A4, B3 and B4 are not divided, and the position Sx in the X direction is divided into the diagonally divided regions A1 and A1. Use only A2, B1, B2,
Sx = ((A1 + B2) − (A2 + B1)) / (A1 + A2 + B1 + B2)
Can also be detected.

(Second Embodiment)
FIG. 14 is a schematic perspective view showing the main part of the second embodiment of the present invention.

  This embodiment shows a uniaxial linear stage 50 as an actuator. The uniaxial linear stage 50 is supported by a linear guide such as a cross roller guide so that the movable portion 52 can move in the X direction with respect to the fixed portion 51, and in the X direction by a servo motor and a feed screw (not shown). It is designed to be driven.

  The LED unit 9 shown in the first embodiment is attached to the side surface of the movable portion 52, and the light receiving element 24 having the light receiving region 30 shown in the first embodiment is arranged on the fixed portion 51 side. The spot 29 is projected from the LED unit 9 to the light receiving area 30, and the output of the light receiving area 30 is processed in the same manner as in the first embodiment.

  Therefore, according to the present embodiment, it is possible to detect the position in the X direction when the movable portion 52 linearly moves in the X direction, and to relate to the amount that the movable portion 52 has moved or inclined in the Y direction due to the swell of the linear guide or the like. Value can be obtained.

(Third embodiment)
FIG. 15 is a schematic perspective view showing a main part of a galvanometer mirror 60 according to the third embodiment of the present invention.

  This galvanometer mirror 60 is a modification of the galvanometer mirror 1 shown in the first embodiment, and the same functional parts as those in the first embodiment are given the same numbers, and the parts other than the description are the same as those in the first embodiment. Since they are similar, they are shown in a simplified manner.

  That is, in the present embodiment, instead of the LED unit 9 of the first embodiment, a sensor mirror 63 that is a part of an optical sensor is disposed on the movable unit 2 with the mirror 3 and the rotation center G interposed therebetween. An LED 61 and a collimator lens 62 are disposed on the substrate 23 attached to the base 21 together with the light receiving element 24 having the light receiving region 30, and the light beam emitted from the LED 61 is converted into parallel light by the collimator lens 62 to be sensor. The light is projected onto the mirror 63 and the reflected light enters the light receiving region 30 as a spot 29.

  Therefore, when the movable part 2 is tilted in the θx direction, the reflected light from the sensor mirror 63 is tilted in the Y direction, and the spot 29 on the light receiving region 30 is also moved in the Y direction, and when the movable part 2 is tilted in the θy direction, the sensor The reflected light from the mirror 63 is tilted in the X direction, and the spot 29 on the light receiving region 30 is also moved in the X direction. Therefore, as in the first embodiment, the output related to the tilt amount in the two directions of the movable portion 2. Can be obtained.

  According to the present embodiment, the LED 61 is disposed not on the movable portion 2 but on the base 21 side substrate 23 and the sensor mirror 63 is disposed on the movable portion 2, so that it is not necessary to supply LED current to the movable portion 2. Thus, power feeding is facilitated and the configuration of the movable part 2 can be simplified.

In addition, the light beam from the LED 61 is incident on the sensor mirror 63 at an angle parallel to the YZ plane. Here, since the YZ plane includes the Y axis, which is a rotation axis having a large tilt angle, when the movable portion 2 rotates θy around the Y axis, the reflected light is at an angle smaller than twice θy. Will be reflected. For example, when the incident angle to the sensor mirror 63 is 45 degrees, it is ^2½ times θy. On the other hand, when the movable part 2 rotates by θx around the X axis, the reflected light from the sensor mirror 63 is inclined twice as much as θx. As described above, in the present embodiment, the direction in which the tilt magnification of the reflected light from the sensor mirror 63 is small is the θy direction having a large rotation angle, and therefore the length of the light receiving region 30 in the large rotation angle direction is shortened. The light receiving element 24 can be downsized.

  FIGS. 16A to 16C show three modifications of the light receiving region 30 in the light receiving element 24 shown in the first to third embodiments.

  In the light receiving region 30 shown in FIG. 16A, both ends in the X direction are lengthened, and the region A2 and the region A4, the region A1 and the region A3, the region B1 and the region B3, and the region B2 and the region B4 described in the above embodiment are used. Are respectively connected at the ends in the X direction and newly divided into a total of four regions A2, A1, B1, and B2. That is, the first dividing line 40 is divided into the first area A and the second area B, and the first area A is divided into the dividing line 41 parallel to the X direction and the two inclined with respect to the X direction. The second dividing lines 42 and 42 are divided into areas A2 and A1, and similarly, the second area B is also divided into a dividing line 41 parallel to the X direction and two second dividing lines inclined with respect to the X direction. 42 and 42 are divided into areas B1 and B2.

  In this way, wiring to the light receiving element 24 can be facilitated by connecting regions to which outputs are added when calculating the X direction position Sx and the Y direction position Sy.

  In the light receiving region 30 shown in FIG. 16B, the direction of a part of the second dividing line 42 is reversed to reduce the dividing region from eight to six. The number is changed from a maximum of 4 to a maximum of 3 in the above embodiment. That is, the first dividing line 40 is divided into a first area A and a second area B, and the first area A is further divided into three parts by two second dividing lines 42 and 42 having opposite inclination directions. Similarly, the second region B is also divided into three by two second dividing lines 42 and 42 having opposite inclination directions.

  Here, the dividing line does not have light receiving sensitivity, and its width is several microns to several tens of microns when it is formed by masking a light receiving region made of, for example, silicon. Therefore, as shown in FIG. 16B, if the number of dividing lines is reduced, the light receiving area can be increased correspondingly, so that an output with high amplitude and low noise can be obtained and position detection accuracy can be improved.

  The light receiving region 30 shown in FIG. 16C is divided into two in the Y direction by a first dividing line 40 parallel to the X direction that requires a wide detection range, and further to the second region B. The first region A and the second region B are each divided into two by a second dividing line 42 inclined with respect to the X direction, and divided into a total of four regions.

  Thus, even if the light receiving region 30 is divided into four, it is possible to configure an optical sensor that has a wide detection range of the X direction position and can also detect the Y direction position orthogonal to the X direction.

  In the first to third embodiments, the light receiving region 30 is divided into eight regions. However, the number of divided regions may be appropriately increased or decreased according to the influence of the width of the dividing line, the influence of crosstalk, and the like. good.

(Fourth embodiment)
FIG. 17 shows a configuration of a main part of an optical sensor according to the fourth embodiment of the present invention.

  In the present embodiment, in the above-described embodiment, the light receiving region 30 of the light receiving element that constitutes the optical sensor is represented by two first dividing lines 44 and 44 parallel to the X direction that require a wide detection range. The first area A, the second area B, and the third area C are divided into three areas in the direction, and the second area B in the center is divided into two areas by a second dividing line 43 oblique to the X direction. It is divided into B1 and B2.

In this case, the X-direction position Sx of the spot 29 with respect to the light receiving region 30 is
Sx = (B2-B1) / (B1 + B2)
The Y-direction position Sy is
Sy = (A−C)) / (A + C)
It can ask for.

  In this way, the calculation can be simplified by dedicating the area without using the area for detecting the position in the X direction and the Y direction.

(Fifth embodiment)
FIG. 18 shows a configuration of a main part of an optical sensor according to the fifth embodiment of the present invention.

  In the present embodiment, in the above-described embodiment, the light receiving region 70 of the light receiving element that constitutes the optical sensor is represented by two first dividing lines 74 and 74 parallel to the X direction that require a wide detection range. The first region A, the second region B, and the third region C divided in the direction are configured with the first region A and the third region C at both ends being silicon PIN photodiodes, and the second region at the center. The region B is a position detection element that outputs a signal related to the center of gravity of the light quantity only in the X direction, which is equivalent to S5629 manufactured by Hamamatsu Photonics, for example. The spot 29 projected to the light receiving area 70 is a rectangle that is long in the Y direction.

  Therefore, since an output related to the center of gravity of the light quantity in the X direction of the spot 29 can be obtained from the second region B at the center, the position of the spot 29 in the X direction can be detected. In addition, since the spot 29 is a rectangle that is long in the Y direction, the outer shape of the spot 29 in the second region B does not change even if the spot 29 moves in the Y direction. Therefore, the position detection error in the X direction when the spot 29 moves in the Y direction can be reduced. The Y-direction position Sy can be obtained from the outputs of the first area A and the third area C by Sy = (A−C) / (A + C).

  In this way, the light receiving region 70 is divided into three in the Y direction, and the second region B in the center is used as a position detection element, so that the light receiving region 70 is divided in the X direction at a wide X direction position. Without being detected from the output of the second region B. In addition, since the central portion of the rectangular spot 29 is incident on the second region B, the intensity change in the Y direction can be particularly reduced. Therefore, the position detection error in the X direction when the spot 29 is displaced in the Y direction. Can be reduced. Further, the first region A and the third region C at both ends in the Y direction of the light receiving region 70 are used as high-sensitivity silicon PIN photodiodes, and the position in the Y direction is detected by the operation of the output. The direction position can be detected with high accuracy.

  In addition, this invention is not limited to the said embodiment and modification, Many modifications or changes are possible. For example, the present invention is not limited to detecting the tilt of a galvanometer mirror or detecting the position of a linear stage, but can also be applied to detecting the position of an objective lens in an optical recording apparatus such as a CD, or detecting the position of a moving body such as a voice coil motor. It is. Further, for example, in the first embodiment, the LED 10 that is a light source is disposed on the movable portion 2, but the LED 2 can be disposed on the stage 21 side that is a fixed portion, and the light receiving element 24 can be disposed on the movable portion 2. Furthermore, it is possible to use a combination of the light receiving region dividing method described in the above embodiment and the modified examples, an example using a reflecting mirror, and the like as appropriate.

  In addition, the light receiving area is not limited to the case where the continuous light receiving area is divided by the dividing line, and can be configured by combining independent small light receiving elements, and is not limited to the silicon PIN photodiode or the position detecting element. An avalanche photodiode or scintillator having photosensitivity can also be used. Furthermore, the spot shape projected on the light receiving region is not limited to an ellipse or a rectangle, but can be appropriately selected as another shape such as a circle. The light beam to be projected is not limited to infrared light with a wavelength of 900 nm, and is visible. Light in the broad sense such as light, ultraviolet light, and X-rays can be used. In the above embodiment, the position and inclination of light on the light receiving area are detected. By differentiating this signal, signals related to speed, acceleration, angular velocity, angular acceleration are generated, and these signals are generated. Can be used to drive and control a movable part having an optical element or the like, or to control other devices related to the movable part. For example, in an optical disk recording / reproducing apparatus, the speed in the tracking direction of the objective lens in the objective lens driving apparatus can be detected, and the signal can be used for driving control of a coarse access driving apparatus equipped with the objective lens driving apparatus. .

It is the perspective view which looked at the galvanometer mirror 1 which concerns on 1st Embodiment of this invention from the front diagonally upward of the mirror 3. FIG. Similarly, it is the perspective view which looked at the galvanometer mirror 1 from the back side. 1 is an exploded perspective view of the entire galvanometer mirror 1. FIG. 2 is an exploded perspective view of a movable part 2 of a galvanometer mirror 1. 2 is a cross-sectional perspective view of the galvanometer mirror 1 cut along an XZ plane passing through the rotation center G of the mirror 3. FIG. Similarly, it is a cross-sectional plan view cut along a YZ plane passing through the rotation center G. FIG. 6 is a cross-sectional plan view showing a state where the movable part 2 is rotated about the Y axis from the state shown in FIG. 5. 2 is a perspective view showing a driving means of the galvanometer mirror 1. FIG. Similarly, it is a top view which shows a drive means. 4 is an exploded perspective view of the LED unit 9. FIG. It is a figure which shows the optical sensor. FIG. 3 is a diagram showing a configuration of a light receiving region 30 of a light receiving element 24. It is a figure which shows the detection characteristic of the X direction position Sx by the optical sensor 38, and the Y direction position Sy. It is a schematic perspective view which shows the principal part of the uniaxial linear stage 50 which concerns on 2nd Embodiment of this invention. It is a schematic perspective view which shows the principal part of the galvanometer mirror 60 which concerns on 3rd Embodiment of this invention. It is a figure which shows the three modifications of the light reception area | region 30 in the light receiving element 24 shown to 1st-3rd embodiment. It is a figure which shows the structure of the principal part of the optical sensor which concerns on 4th Embodiment of this invention. It is a figure which shows the structure of the principal part of the optical sensor which concerns on 5th Embodiment of this invention. It is a figure which shows an example of the actuator using the conventional optical sensor. Similarly, it is a figure which shows another example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Galvano mirror 2 Movable part 3 Mirror 4 Holder 4h Post 5 Flexible substrate 6 Pivot 7 EL coil 8 AZ coil 9 LED unit 10 LED
11 Substrate 12 Balancer 12a Aperture 13 Wire 21 Base 21b Bar 22 Substrate Unit 23 Substrate 24 Light-Receiving Element 27 Magnet 28 Yoke 29 Spot 30 Light-Receiving Area 38 Photosensor 40 First Dividing Line 41 Dividing Line 42 Second Dividing Line 44 First Dividing line 50 Linear stage 51 Fixed part 52 Movable part 60 Galvano mirror 61 LED
62 collimator lens 63 sensor mirror 70 light receiving area 74 first dividing line

Claims (15)

In an optical sensor that includes a light source and a light receiving element that receives a light beam from the light source, and detects a movement position in a two-dimensional direction of the incident light beam based on an output of the light receiving element.
The light receiving region of the light receiving element includes a first region and a second region divided by a first dividing line parallel to a first direction, and at least of the first region and the second region One is divided by a second dividing line inclined with respect to the first dividing line.   The information related to the position of the light beam in the first direction and a second direction perpendicular to the first direction is output based on the output of the light receiving region. Optical sensor.   Outputs information related to the position of the light beam in the first direction based on an output difference between at least two regions divided by the second dividing line, and the first region, the second region, 3. The optical sensor according to claim 2, wherein information related to a position of the light beam in the second direction is output based on the output difference between the two. In an optical sensor that includes a light source and a light receiving element that receives a light beam from the light source, and detects a movement position in a two-dimensional direction of the incident light beam based on an output of the light receiving element.
The light receiving area of the light receiving element includes a first area, a second area, and a third area divided by two first dividing lines parallel to the first direction, and the second area at the center. The region is divided by a second dividing line inclined with respect to the first dividing line.   The information related to the position of the light beam in the first direction and a second direction perpendicular to the first direction is output based on the output of the light receiving region. Optical sensor.   Outputting information related to the position of the light beam in the first direction based on an output difference between at least two regions of the second region divided by the second dividing line; 6. The light according to claim 5, wherein information relating to the position of the light beam in the second direction is output based on an output difference between the first region and the third region located on both sides. Sensor. In an optical sensor that includes a light source and a light receiving element that receives a light beam from the light source, and detects a movement position in a two-dimensional direction of the incident light beam based on an output of the light receiving element.
The light receiving region of the light receiving element includes a first region, a second region, and a third region divided by two first dividing lines parallel to the first direction,
Outputs information related to the position of the light beam in a second direction substantially orthogonal to the first direction based on the outputs of the first region and the third region located on both sides of the second region. And outputting information related to the position of the light beam in the first direction based on the output of the second region.   The optical sensor according to claim 7, wherein the second region includes a position detection element.   The optical sensor according to claim 7, wherein the first region and the third region are formed of a photodiode.   10. The position detection range of the light beam in the first direction is larger than the position detection range of the light beam in the second direction. 10. Light sensor.   11. The spot of the light beam incident on the light receiving region has a shape in which the second direction is larger than the first direction. 11. Light sensor.   An actuator comprising: a movable part movable with respect to a fixed part; and the optical sensor according to any one of claims 1 to 11 that detects a position and / or an inclination amount of the movable part.   The actuator according to claim 12, wherein the movable part includes at least an optical element.   The actuator according to claim 13, wherein the optical element is a mirror.   15. The actuator according to claim 13, wherein a part of the optical sensor is disposed on the movable part on a side opposite to the optical element with respect to a center of gravity of the movable part.

Images