JP2004028724A - Rotation detector and lens driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotation detector including one optical sensor and one rotor capable of detecting an amount and direction of rotation of a detected body. <P>SOLUTION: The rotation detector is provided with a transmittance optical sensor 120 and a rotor 110 having a plurality of blades 111 radially arranged, in which information relating the rotation of the detected body operatively associated with the rotor 110 according to an output signal of the optical sensor 120 varied when the blade crosses over an optical path. Each of the blades 111 is formed by an interrupting blade 111a interrupting the transmittance of light, and a transmittance blade 111b permitting the transmittance of a predetermined amount of light. Thereby, the amount and direction of the rotation of the detected body can be detected with a simple structure without an increase in number of components. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rotation detector for detecting rotation information of a rotating object to be detected and a lens driving device using the same, and in particular, a rotation detector including a rotor interlocked with the object to be detected and a transmission type optical sensor. And a lens driving device.
[0002]
[Prior art]
As a lens drive device mounted on a camera or the like, there is known a lens drive device that rotates a cam barrel or the like via a gear or the like by a motor and reciprocates the lens barrel in the optical axis direction to perform a magnification (zoom) adjustment. ing. This apparatus employs a rotation detector having a transmission-type optical sensor and a rotor to detect the extension position of the lens barrel, and performs a zooming operation based on information obtained from the rotation detector. (Zooming) and focusing operation (focusing).
[0003]
As shown in FIG. 9A, the rotation detector includes a rotor 1 including three blades 1b radially arranged at equal intervals around a rotation axis 1a, and a transmission type including a light emitting element and a light receiving element. And an optical sensor (photo interrupter) 2. Then, by using the fact that the blade 1b blocks the light incident on the light receiving element and an ON / OFF signal is obtained as shown in FIG. 9B, the rotation amount of the motor linked to the rotor 1, that is, , For detecting the zoom position (zoom amount) of the lens barrel.
[0004]
[Problems to be solved by the invention]
In the lens driving device as described above, in order to extend and retract the lens barrel, it is necessary to detect the rotation direction of the motor in order to rotate the motor forward and backward. In addition, a backlash or the like may occur between the motor and the rotor 1 that is interlocked via gears or the like, so that the rotation of the two may be deviated. There is a method of detecting the direction and correcting the rotational deviation based on the information.
By the way, in order to detect the rotation direction, a method of employing one optical sensor having two sets of light-emitting elements and light-receiving elements as the optical sensor 2 or a light having one set of light-emitting elements and light-receiving elements There are techniques that employ two sets of sensors and rotors. However, these techniques cause an increase in the number of parts, an increase in cost, and an increase in the size of the apparatus.
[0005]
Further, in the above-described conventional rotor 1, particularly when rotating at high speed, noise such as wind noise may be generated by the edge of each blade 1b. Therefore, when such a rotation detector is unpleasant for a photographer or is applied to a lens driving device such as a digital camera or a digital video camera capable of recording, there is a problem that the recording is performed as noise.
[0006]
The present invention has been made in view of the above-described problems of the related art, and aims at simplification of the structure, reduction in the size of the apparatus by reducing the number of parts, and cost reduction, and the like. It is an object of the present invention to provide a rotation detector capable of detecting information about rotation such as the rotation amount and the rotation direction of a detection object with high accuracy, and a lens driving device using the same.
[0007]
[Means for Solving the Problems]
The rotation detector of the present invention is a transmission-type optical sensor that outputs a signal according to the amount of light incident on the light-receiving element from the light-emitting element, and is radially arranged to cross the optical path between the light-emitting element and the light-receiving element A rotor having a plurality of blades, a rotation detector for detecting information about the rotation of a detection target interlocked with the rotor based on an output signal of an optical sensor that changes as the blades traverse the optical path; Are characterized by including blades having different light transmission amounts.
According to this configuration, since the plurality of blades include blades having different light transmission amounts, different output waveforms can be obtained when the rotor rotates in one direction and when the rotor rotates in the other direction. . Accordingly, the rotation amount and the rotation direction of the detection target can be detected with a simple structure without increasing the number of components.
[0008]
In the rotation detector, the plurality of blades may have a configuration including a blocking blade that blocks transmission of light and a transmission blade that allows transmission of a predetermined amount of light.
According to this configuration, a ternary signal including a signal when the blocking blade is interposed, a signal when the transmission blade is interposed, and a signal when the blade is not interposed is obtained for the optical sensor. Therefore, an output waveform in which the order in which these three signals are generated differs depending on the rotation direction is obtained, and the rotation amount and the rotation direction of the detection target can be detected.
[0009]
In the rotation detector, a configuration may be adopted in which at least one of the plurality of blades has at least two regions having different light transmission amounts.
According to this configuration, different output waveforms can be obtained simply by reciprocating the rotor by the angle of one blade, so that the rotation amount and the rotation direction of the detection target can be detected more quickly and more accurately. .
[0010]
In the rotation detector, a configuration may be adopted in which the plurality of blades are formed in a disc shape by being integrally connected to each other with a transparent material that allows light to pass therethrough.
According to this configuration, since the plurality of blades are integrally connected to each other and have a disk shape in which no edge is formed, even when the rotor rotates at high speed, generation of wind noise and the like can be prevented.
[0011]
In the rotation detector, the plurality of blades are formed by performing a surface treatment on a disk formed of a transparent resin material that allows light to pass therethrough to define portions having different light transmission amounts. Yes, the configuration can be adopted.
According to this configuration, the structure and manufacture of the rotor are simplified, and the cost can be reduced. Also, by appropriately changing the pattern of the surface treatment (for example, coating of a film, printing of a film, etc.), portions having different light transmission amounts can be easily formed in various patterns as necessary. it can.
[0012]
A lens driving device according to the present invention relates to a variable power optical system including a lens for changing a photographing magnification of a subject, a driving mechanism including a motor that drives the variable power optical system to move in the optical axis direction, and rotation of the motor. A rotation detector for detecting information, wherein the rotation detector is a transmission type optical sensor that outputs a signal according to the amount of light incident on the light receiving element from the light emitting element, and a light emitting element And a rotor having a plurality of blades radially arranged so as to cross an optical path between the light receiving element and a rotor linked to a motor, wherein the plurality of blades include blades having different light transmission amounts. Features.
According to this configuration, since the plurality of blades include blades having different light transmission amounts, different output waveforms can be obtained when the rotor rotates in one direction and when the rotor rotates in the other direction. . Accordingly, the rotation amount and the rotation direction of the motor can be detected with a simple structure without increasing the number of components, and the variable power optical system can be positioned at a desired variable power position with high accuracy.
[0013]
In the lens driving device, the plurality of blades may have a configuration including a blocking blade that blocks transmission of light and a transmission blade that allows transmission of a predetermined amount of light.
According to this configuration, a ternary signal including a signal when the blocking blade is interposed, a signal when the transmission blade is interposed, and a signal when the blade is not interposed is obtained for the optical sensor. That is, an output waveform in which the order of generation of these three types of signals is different depending on the rotation direction can be obtained, so that the rotation amount and the rotation direction of the motor can be reliably detected, and the variable power optical system can be precisely positioned at a desired variable power position. Can be positioned.
[0014]
In the above-described lens driving device, a configuration can be adopted in which at least one of the plurality of blades has at least two regions having different light transmission amounts.
According to this configuration, since a different output waveform can be obtained only by the reciprocating movement of the rotor by the angle of one blade, the rotation amount and the rotation direction of the motor can be detected more quickly and accurately, and the variable power optical system can be detected. Positioning can be performed with high accuracy while finely adjusting to a desired zooming position.
[0015]
In the above-described lens driving device, a configuration can be adopted in which the plurality of blades are formed in a disc shape by being integrally connected to each other with a transparent material that allows light to pass therethrough.
According to this configuration, since the plurality of blades are integrally connected to each other and have a disk shape in which no edge is formed, even when the rotor rotates at high speed, generation of wind noise and the like can be prevented. When this device is mounted on a digital camera, a digital video camera, or the like capable of recording, noise caused by the rotor can be prevented from being recorded.
[0016]
In the above-described lens driving device, the plurality of blades are formed by performing a surface treatment on a disk formed of a transparent resin material that allows light to pass therethrough, thereby defining portions having different light transmission amounts. Yes, the configuration can be adopted.
According to this configuration, the structure and manufacturing of the rotor are simplified, the cost can be reduced, and by appropriately changing the pattern of the surface treatment, portions having different light transmission amounts can be variously changed as necessary. Since it can be easily formed in a pattern, cost reduction can be achieved even in a lens driving device that can produce not only a large number of kinds and a large amount but also a large number of kinds and a small amount.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
1 to 4 show an embodiment of a lens driving device and a rotation detector according to the present invention. FIG. 1 is a front view of the device, FIG. 2 is a sectional view showing an internal structure, and FIG. FIG. 4 is a perspective view showing a detector and a waveform diagram showing an output signal, and FIG. 4 is a waveform diagram showing output signals of the rotation detector in forward rotation and reverse rotation.
[0018]
As shown in FIGS. 1 and 2, the lens driving device has a base 10 having a substantially rectangular outline, to which a low-pass filter 11 and a CCD (charge coupled device) 12 are attached. A cylindrical fixed cylinder 20 having an axial center, a cylindrical cam 30 rotatably and linearly supported inside the fixed cylinder 20, and a first lens supported movably in the optical axis direction L inside the cylindrical cam 30 The group 40 and the second lens group 50, the third lens group 60 movably supported in the optical axis direction L with respect to the base 10, and the first lens group 40 and the second lens group by transmitting a driving force to the cylindrical cam 30. A driving mechanism 70 for driving the driving mechanism 50, a driving mechanism 80 for driving the third lens group 60, a rotation detector 100 for detecting rotation information of the driving mechanism 70, and a detector for detecting a home position of the cylindrical cam 30 30, and a control circuit for controlling the driving of the drive mechanism 70, 80.
[0019]
As shown in FIG. 2, the cylindrical cam 30 includes three follower pins 31 (partially omitted in the figure) formed on the outer peripheral surface, an arcuate gear 32, a first lens group 40, and a second lens group 50. The three cam grooves 33 and 34 (partially omitted in the figure) formed on the inner peripheral surface to exert the function, the rotation of the first lens group 40 and the second lens group 50, and the optical axis direction L And a guide cylinder 35 for guiding to the other end. The three follower pins 31 are inserted into three cam grooves 21 (partially omitted in the figure) formed in the fixed barrel 20, and the cylindrical cam 30 is rotated by the drive mechanism 70 to rotate in the optical axis direction. Forward and backward at L.
[0020]
As shown in FIG. 2, the first lens group 40 includes a lens G <b> 1, a lens frame 41 holding the lens G <b> 1, and three follower pins 42 formed on the lens frame 41 and inserted into the respective cam grooves 33 (partly shown in the figure). Is omitted). When the cylindrical cam 30 rotates, the first lens group 40 moves forward and backward in the optical axis direction L.
[0021]
As shown in FIG. 2, the second lens group 50 includes a lens G2, a lens frame 51 holding the lens G2, and three follower pins 52 (one in FIG. 2) formed in the lens frame 51 and inserted into the respective cam grooves 34. And a shutter unit S fixed to the lens frame 51. When the cylindrical cam 30 rotates, the second lens group 50 moves forward and backward in the optical axis direction L.
That is, the first lens group 40 and the second lens group 50 function as a variable power optical system for changing the photographing magnification of the subject on the imaging plane of the CCD 12.
[0022]
As shown in FIG. 2, the third lens group 60 includes a lens G3 and a lens frame 61 that holds the lens G3. A nut is held on the lens frame 61 outside the fixed barrel 20.
The drive mechanism 80 is formed by a step motor 81, a lead screw screwed into a nut held by the lens frame 61, and driven by the step motor 81. Then, when the step motor 81 rotates, the third lens group 60 moves forward or backward in the optical axis direction L via the lead screw and the nut.
That is, when the first lens group 40 and the second lens group 50 change the magnification of the first lens group 40 and the second lens group 50, the third lens group 60 focuses on the subject when the focus on the imaging plane of the CCD 12 is shifted. It functions as a focusing optical system that performs a focusing operation (focusing).
[0023]
As shown in FIGS. 1 and 2, the drive mechanism 70 includes a DC motor 71 fixed to the base 10, a worm 72 fixed to the drive shaft 71 a and integrally provided with a gear 72 a, and supported by the base 10 and mounted on the worm 72. A worm wheel 73 that meshes, a worm 74 that is integrally formed coaxially with the worm wheel 73, a worm wheel 75 that is supported by the base 10 and meshes with the worm 74, and a gear that is integrally formed coaxially with the worm wheel 75 76, a gear 77 supported by the base 10 and the fixed cylinder 20 and meshed with the gear 76 and the arc gear 32.
[0024]
As shown in FIGS. 1 and 2, the rotation detector 100 is formed by a rotor 110 that is rotated via a gear 101 that meshes with a gear 72a, and a transmission-type optical sensor 120, and serves as a detection target. This is for detecting information (rotation amount and rotation direction) related to the rotation of the DC motor 71.
As shown in FIG. 2, the rotor 110 is rotatably supported by a support shaft 13 of the base 10, and includes a plurality of (here, three) blades 111 radially arranged around the rotation axis. It is formed of a resin material so as to define a gear 112 that meshes with the gear 101.
[0025]
As shown in FIG. 3A, the plurality of blades 111 are formed by two blocking blades 111a that block transmission of light and one transmission blade 111b that allows transmission of a predetermined amount of light. I have. The blocking blade 111a and the transmission blade 111b are each formed in a fan shape having a central angle of about 60 degrees, and are arranged at intervals of about 60 degrees around the rotation axis S (about every 120 degrees between the centers of the blades 111). ing.
[0026]
Here, the rotor 110 includes a blocking blade 111a formed of a resin material that blocks light (for example, opaque) and a transmission blade 111b formed of a resin material that transmits a predetermined amount of light (for example, translucent). It may be formed by integrally molding and then integrally joining, or it may be formed entirely of a resin material that allows a predetermined amount of light to pass therethrough (for example, translucent). The blocking blade 111a may be formed by using the same as the transmitting blade 111b and subjecting the two blades to a surface treatment so as not to transmit light. Incidentally, as the surface treatment, a method such as painting or printing can be adopted.
[0027]
As shown in FIGS. 2 and 3A, the transmissive optical sensor 120 includes a light emitting element 121 that emits detection light, and a light receiving element 122 that receives detection light from the light emitting element 121. As the rotor 110 rotates and the blades 111 cross the optical path between the light emitting element 121 and the light receiving element 122, a signal corresponding to the amount of light incident on the light receiving element 122 is output.
As shown in FIG. 3B, the signal output from the optical sensor 120 is the signal S1 (0 V) when the blocking blade 111a is interposed between the optical paths, and the blade 111 (111a, 111b) is not interposed between the optical paths. When the transmission blade 111b is interposed between the optical path and the signal S2 (Vh), three signals (three values) of the signal S3 (Vm) are continuously output.
[0028]
Here, the operation of the rotation detector 100 (the rotor 110 and the optical sensor 120) will be described with reference to FIG. 4. For example, the rotor 110 is rotating clockwise in FIG. 3A (forward rotation). Then, as shown in FIG. 4A, the same waveform is repeated and output every cycle T.
Then, when the rotor 110 is rotated counterclockwise at point P from the state where the rotor 110 is normally rotated clockwise in FIG. 3A, for example, as shown in FIG. A waveform different from the waveform at the time of normal rotation in which only one S1 signal is generated in between is output. Therefore, it is possible to detect that the rotation direction has changed at the switching timing point P.
[0029]
In the drive mechanism 70, when the DC motor 71 rotates, the cylindrical cam 30 rotates via the worm 72, the worm wheel 73, the worm 74, the worm wheel 75, the gear 76, and the gear 77, and the first lens group 40 and The second lens group 50 moves forward or backward in the optical axis direction L, respectively. When the DC motor 71 rotates, the rotor 110 (blade 111) rotates via the gear 72a and the gear 101, and the optical sensor 120 outputs a signal.
That is, when the first lens group 40 and the second lens 50 move from the home position and perform a zooming operation by the rotation of the DC motor 71, the rotation detector 100 controls the DC motors corresponding to those zooming positions. The rotation amount of the DC motor 71 is detected while the rotation amount of the DC motor 71 is detected.
[0030]
Next, a general operation when the above-described lens driving device is mounted on a digital camera will be described.
First, in the retracted state where photographing is not performed, the first lens group 40 and the second lens group 50 are in the retracted position retracted backward in the optical axis direction L.
[0031]
In this state, when the operator turns on the main switch, the CCD 12 operates, and the DC motor 71 and the step motor 81 operate to operate the first lens group 40, the second lens group 50, and the third lens group 60. Are positioned at a predetermined home position (the wide-angle end photographing position shown in FIG. 2), and the focusing operation is automatically started. At this time, the home positions of the first lens group 40 and the second lens group 50 are detected by the detector 130.
[0032]
Subsequently, when the operator presses the zoom button from this state, the DC motor 71 rotates in a predetermined direction, and zooming (magnification operation) of the first lens group 40 and the second lens group 50 is started. Then, when the operator stops operating the zoom button, desired zooming is completed.
[0033]
Here, in the zooming and the focusing control accompanying the zooming, the rotation amount and the rotation direction (zoom position information) of the DC motor 71 from the home position are detected by the rotation detector 100. Then, based on the detected zoom position information and the storage information stored in the storage unit or the like in advance, the step motor 81 is driven, and the third lens group 60 is driven to a desired position as needed to perform focusing.
[0034]
Here, even if the gears and the like rotate in reverse due to an external impact or the like applied to the drive mechanism 70, the information (rotation amount and direction) of the rotation of the DC motor 71 is detected by the rotation detector 100 with high accuracy. The DC motor 71 is feedback-controlled based on the detection information, and is finely adjusted and rotationally corrected, so that the first lens group 40 and the second lens group 50 are positioned at desired zooming positions (telephoto shooting positions). Thereafter, when the operator presses the release button, an image of the subject is photographed by the CCD 12, and after predetermined image processing is performed by the image processing circuit, the image is stored in the image storage unit.
[0035]
On the other hand, when the first lens group 40 and the second lens group 50 are moved from the predetermined telephoto shooting position to the wide-angle end shooting position, the DC motor 71 rotates in the reverse direction and stops when the predetermined rotation amount is reached. I do. Also in this zooming control, since the rotation detector 100 detects the rotation amount and the rotation direction of the DC motor 71 with high precision, the first lens group 40 and the second lens group 50 are positioned with high precision at the wide-angle end photographing position. Is done.
Then, when the detector 130 detects that the cylindrical cam 30 has reached the home position, the detection pulse in the rotation detector 100 is initialized based on this detection signal.
As described above, by employing the rotation detector 100 using the rotor 110 including the blades having different light transmission amounts, the variable magnification optical systems (40, 50) and the focusing optical system (60) can be reliably driven. It can be controlled and can be positioned with high accuracy.
[0036]
FIG. 5A shows another embodiment of the rotation detector according to the present invention. The rotation detector 200 is formed by a rotor 210 and the optical sensor 120 described above.
As shown in FIG. 5A, the rotor 210 has two blocking blades 211a radially arranged around its rotation axis S to block transmission of light and one of the blades 211 that allows transmission of a predetermined amount of light. It is formed of a resin material so as to define a transmission blade 211b, three transparent plates 211c connecting between the blades 211a and 211b, and a gear 212 meshing with the gear 101.
Here, after the blocking blade 211a and the gear 212 are integrally formed, the transmission blade 211b and the transparent plate 211c are integrally connected.
[0037]
According to the rotation detector 200, since the output signal as shown in FIG. 4 is obtained, the rotation amount and the rotation direction of the detection target (the DC motor 71 and the like) are detected with high accuracy. Further, since the rotor 210 is formed in a disk shape, the edges of the blades 211a and 211b are eliminated, so that even when the rotor 210 rotates at high speed, generation of wind noise and the like is prevented. Therefore, when the rotation detector 200 is employed in a lens drive device such as a digital video camera capable of recording, noise caused by the rotor 210 is not recorded, and only a desired sound is recorded.
[0038]
FIG. 5B shows another embodiment of the rotation detector according to the present invention. The rotation detector 300 is formed by the rotor 310 and the optical sensor 120 described above.
As shown in FIG. 5B, the rotor 310 is formed with a disk 311 using a transparent resin material that allows light transmission so that the gear 312 is integrally provided. By performing the processing, two blocking blades 313a that are radially arranged around the rotation axis S and block transmission of light and one transmission blade 313b that allows transmission of a predetermined amount of light are defined.
As the surface treatment, application of an opaque paint and a translucent paint, printing of an opaque resin material and a translucent resin material, and the like can be adopted.
[0039]
According to the rotation detector 300, since the output signal as shown in FIG. 4 is obtained, the rotation amount and the rotation direction of the detection target (the DC motor 71 and the like) are detected with high accuracy. Further, since the rotor 310 is formed in a disk shape, generation of wind noise and the like is prevented even when the rotor 310 is rotated at a high speed. Therefore, when the rotation detector 300 is employed in a lens drive device such as a digital video camera capable of recording, noise caused by the rotor 310 is not recorded, and only a desired sound is recorded.
Further, since the manufacturing of the rotor 310 is simplified, the manufacturing cost is reduced, and a portion having a different light transmission amount can be formed into various patterns as necessary by appropriately changing the pattern of the surface treatment. In addition, cost reduction can be achieved even in the case of small-lot production of many kinds.
[0040]
FIG. 6 shows another embodiment of the rotation detector according to the present invention. The rotation detector 400 is formed by the rotor 410 and the optical sensor 120 described above.
As shown in FIG. 6A, the rotor 410 is formed of a resin material so as to define three blades 411 arranged radially around the rotation axis S and a gear 412. Each of the blades 411 is formed by a blocking region 411a that blocks transmission of light and a transmission region 411b that allows transmission of a predetermined amount of light. That is, each blade 411 is formed to have two regions having different light transmission amounts.
[0041]
As shown in FIG. 6B, the output signal of the rotation detector 400 includes a signal S1 (0V) when the blocking region 411a of the blade 411 is interposed between the optical paths when the rotor 410 rotates clockwise. The signal S2 (Vh) is continuously output when the blade 411 is not interposed between the optical paths, and the signal S3 (Vm) when the transmission region 411b of the blade 411 is interposed between the optical paths. .
[0042]
Here, the operation of the rotation detector 400 (the rotor 410 and the optical sensor 120) will be described with reference to FIG. 7. For example, the rotor 410 is rotating clockwise in FIG. 6A (forward rotation). Then, as shown in FIG. 7A, the same waveform is repeated and output every cycle T.
Therefore, as shown in FIG. 7B, when the rotor 410 is rotated counterclockwise at point P from the state where the rotor 410 is normally rotated clockwise in FIG. 6A, for example, after the S2 signal, Since the waveform at the time of normal rotation at which the S3 signal is output is different from the waveform at the time of normal rotation at which the S2 signal follows the S3 signal, the rotation direction has changed at the switching timing P. Can be detected.
According to the rotation detector 400, since different waveforms can be obtained only by reciprocating the rotor 410 by the angle of one blade 411, the rotation amount of the object to be detected (such as the DC motor 71) can be increased more quickly and accurately. And the rotation direction can be detected.
[0043]
FIG. 8A shows another embodiment of the rotation detector according to the present invention. This rotation detector 500 is formed by a rotor 510 and the optical sensor 120 described above.
As shown in FIG. 8A, the rotor 510 has two blocking blades 511 that are radially arranged around the rotation axis S to block light transmission, a blocking region 512a that blocks light transmission, and the like. A resin is defined so as to define a blade 512 having a transmission area 512b that allows a certain amount of light to pass therethrough, three transparent plates 512 connecting the blades 511 and 512, and a gear 514 meshing with the gear 101. It is formed of a material. Here, after the blocking blade 511, the blocking region 512a of the blade 512 and the gear 514 are integrally formed, the transmission region 512b of the blade 512 and the transparent plate 513 are integrally connected.
[0044]
According to the rotation detector 500, as described above, the rotation amount and the rotation direction of the detection target (the DC motor 71 and the like) are detected with high accuracy. Further, since the rotor 510 is formed in a disk shape, generation of wind noise and the like is prevented even when the rotor 510 rotates at a high speed. Therefore, when the rotation detector 500 is employed in a lens drive device such as a digital video camera capable of recording, noise caused by the rotor 510 is not recorded, and only a desired sound is recorded.
[0045]
FIG. 8B shows another embodiment of the rotation detector according to the present invention. The rotation detector 600 is formed by the rotor 610 and the optical sensor 120 described above.
As shown in FIG. 8B, the rotor 610 is formed with a disk 611 using a transparent resin material that allows transmission of light so that the gear 612 is integrally provided. By performing the processing, three blades 613 radially arranged around the rotation axis S are defined, and each of the blades 613 includes a blocking region 613a for blocking light transmission and a transmission region for allowing a predetermined amount of light to pass. 613b.
As the surface treatment, application of an opaque paint and a translucent paint, printing of an opaque resin material and a translucent resin material, and the like can be adopted.
[0046]
According to the rotation detector 600, since the output signal as shown in FIG. 7 is obtained, the rotation amount and the rotation direction of the object to be detected (such as the DC motor 71) are detected more quickly and more accurately. . Further, since the rotor 610 is formed in a disk shape, generation of wind noise and the like is prevented even when the rotor 610 is rotated at high speed. Therefore, when the rotation detector 600 is employed in a lens drive device such as a digital video camera capable of recording, noise caused by the rotor 610 is not recorded, and only a desired sound is recorded.
[0047]
In the above embodiment, the rotors 110, 210, 310, 410, 510, and 610 having three blades are shown as the rotors constituting the rotation detector. However, the present invention is not limited to this, and more rotors are provided. Although the rotor may be provided with a number of blades, and the rotor is formed of a resin material, the rotor is formed of a resin material. Is also good.
[0048]
【The invention's effect】
As described above, according to the rotation detector and the lens driving device of the present invention, in the rotor having the plurality of blades crossing the optical path in the transmission type optical sensor, the plurality of blades includes the blades having different light transmission amounts. With this configuration, different output waveforms can be obtained depending on whether the rotor rotates in one direction or in the other direction. This makes it possible to detect the rotation amount and the rotation direction of the detection target such as the motor for driving the variable power optical system with a simple structure without increasing the number of parts.
In particular, by providing a transparent material that allows light transmission between a plurality of blades and forming the rotor in a disk shape, even if the rotor rotates at high speed, generation of wind noise and the like can be prevented. Can be. Therefore, by mounting the lens driving device provided with the rotation detector on a digital video camera or the like capable of recording, it is possible to prevent noise caused by the rotor from being recorded.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of a lens driving device to which a rotation detector according to the present invention is applied.
FIG. 2 is a cross-sectional view showing the inside of the lens driving device shown in FIG.
FIG. 3A is a perspective view illustrating an embodiment of a rotation detector according to the present invention, and FIG. 3B is a waveform diagram illustrating an output signal thereof.
FIGS. 4A and 4B are waveform diagrams for explaining the operation of the rotation detector shown in FIG. 3;
FIGS. 5A and 5B are perspective views showing another embodiment of the rotation detector according to the present invention.
FIG. 6A is a perspective view showing another embodiment of the rotation detector according to the present invention, and FIG. 6B is a waveform chart showing an output signal thereof.
FIGS. 7A and 7B are waveform diagrams for explaining the operation of the rotation detector shown in FIG. 6;
8 (a) and 8 (b) are perspective views showing another embodiment of the rotation detector according to the present invention.
9A is a perspective view showing a conventional rotation detector, and FIG. 9B is a waveform chart showing an output signal thereof.
[Explanation of symbols]
10 base
12 CCD
20 fixed cylinder
30 cylindrical cam
40 first lens group (variable optical system)
50 Second lens group (variable magnification optical system)
60 Third lens group
70 Drive mechanism
71 DC motor
100, 200, 300, 400, 500, 600 rotation detector
110, 210, 310, 410, 510, 610 rotor
111 multiple feathers
111a Shuttle vane
111b transmission blade
120 Transmission type optical sensor
121 light emitting element
122 light receiving element
S rotation axis
211a, 313a blocking blade
211b, 313b Transmission blade
211c transparent plate
311 disk
411 Multiple feathers
411a Blocking area
411b Transmission area
511 Shuttle feather
512 feathers
512a Blocking area
512b Transmission area
611 disk
613 multiple feathers
613a Blocking area
613b Transmission area

Claims (10)

A transmission-type optical sensor that outputs a signal according to the amount of light incident on the light-receiving element from the light-emitting element, and a rotor having a plurality of blades radially arranged to cross an optical path between the light-emitting element and the light-receiving element; A rotation detector that detects information related to rotation of a detection target that is interlocked with the rotor based on an output signal of the optical sensor that changes as the blade crosses the optical path,
The plurality of blades include blades having different light transmission amounts,
A rotation detector, characterized in that: The plurality of blades include a blocking blade that blocks transmission of light, and a transmitting blade that allows transmission of a predetermined amount of light,
The rotation detector according to claim 1, wherein: At least one of the plurality of blades has at least two regions having different light transmission amounts,
The rotation detector according to claim 1 or 2, wherein: The plurality of blades are formed in a disc shape by being integrally connected to each other by a transparent material that allows light to pass therethrough,
The rotation detector according to any one of claims 1 to 3, wherein: The plurality of blades are formed by performing a surface treatment on a disk formed of a transparent resin material that allows light to pass therethrough, and defining portions having different light transmission amounts.
The rotation detector according to any one of claims 1 to 4, wherein: A variable power optical system including a lens for changing a photographing magnification of a subject, a drive mechanism including a motor for driving the variable power optical system to move in the optical axis direction, and rotation detection for detecting information on rotation of the motor A lens driving device comprising:
The rotation detector is a transmission-type optical sensor that outputs a signal in accordance with the amount of light incident on the light-receiving element from the light-emitting element, and a plurality of light-emitting elements radially arranged to cross an optical path between the light-emitting element and the light-receiving element. A rotor having a blade and interlocked with the motor, the plurality of blades include blades having different light transmission amounts,
A lens driving device characterized by the above-mentioned. The plurality of blades include a blocking blade that blocks transmission of light, and a transmitting blade that allows transmission of a predetermined amount of light,
The lens driving device according to claim 6, wherein: At least one of the plurality of blades has at least two regions having different light transmission amounts,
The lens driving device according to claim 6 or 7, wherein: The plurality of blades are formed in a disc shape by being integrally connected to each other by a transparent material that allows light to pass therethrough,
9. The lens driving device according to claim 6, wherein: The plurality of blades are formed by performing a surface treatment on a disk formed of a transparent resin material that allows light to pass therethrough, and defining portions having different light transmission amounts.
The lens driving device according to any one of claims 6 to 9, wherein:

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