JP2006178332A - Lens driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens driving device which can detect the initial position of a lens and whose dimension in a direction orthogonal to an optical axis direction is restrained. <P>SOLUTION: The lens driving device is equipped with a turning member formed cylindrically and comprising a magnet 9 and a rotor 8, and a lens barrel 12 moving the lens 10 in the optical axis direction with the turning of the rotor 8, and it is also equipped with a reflection area 13 provided on the lower end face 9a of the magnet 9, and a photosensor 15 arranged to be opposed to the reflection area 13 and comprising a pair of light projecting part 15a and light receiving part 15b. By receiving light from the light projecting part 15a by the light receiving part 15b through the reflection area 13, the initial position of the lens 10 is detected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens driving device that is provided in various electronic devices and the like and can move a lens in an optical axis direction by driving a motor and detect an initial position of the lens.

  There exists a thing shown by patent document 1 as this type of prior art. This prior art includes a stepping motor that moves the lens frame that holds the focus lens group in the optical axis direction, and is provided on the outer peripheral surface of the lens frame as a mechanism for detecting the initial position of the lens, and is orthogonal to the optical axis direction. And a photo interrupter having a pair of light emitting elements and light receiving elements.

In this prior art, when the lens frame is moved by driving the stepping motor, a light-shielding plate provided on the lens frame is inserted between the light-emitting element and the light-receiving element of the photo interrupter, and the light emitted from the light-emitting element is shielded. The initial position of the lens is detected by the output voltage when it is blocked by the plate and is not incident on the light receiving element.
JP-A-6-174999

  In the prior art described above, the mechanism for detecting the initial position of the focus lens group includes a light shielding plate extending in a direction orthogonal to the optical axis direction of the outer peripheral surface of the lens frame, and a direction orthogonal to the optical axis direction. Since the photo interrupter is arranged, the size in the direction orthogonal to the optical axis direction becomes large, which causes a problem that the apparatus cannot be reduced in size.

  The present invention has been made from the above-described prior art, and an object thereof is to provide a lens driving device capable of detecting the initial position of the lens and suppressing the dimension in the direction orthogonal to the optical axis direction. There is to do.

  In order to achieve the above object, the present invention includes a rotating member formed in a cylindrical shape and a lens barrel that moves the lens in the optical axis direction as the rotating member rotates. A reflection region provided on an end surface of the moving member; and a photosensor which is disposed so as to be opposed to the reflection region and includes a pair of light projecting units and a light receiving unit. The light of the light projecting unit is transmitted through the reflection region. The initial position of the lens is detected by receiving light at the light receiving unit.

  In the present invention configured as described above, the mechanism for detecting the initial position of the lens is arranged so that the reflection area provided on the end surface of the rotating member and the reflection area can be opposed to each other. And a photosensor. That is, a member that is extended in a direction orthogonal to the optical axis direction on the outer peripheral surface of the rotating member by the reflection region formed on the end surface of the rotating member and the photosensor including the light projecting unit and the light receiving unit. The initial position of the lens can be detected without providing it. Thereby, the dimension of the direction orthogonal to an optical axis direction can be suppressed.

  According to the present invention, in the above invention, the image sensor is mounted on a substrate positioned below the lens barrel, and the photosensor is mounted on the substrate. Since the imaging device and the photosensor are provided on the same substrate in the present invention configured as described above, the positioning accuracy of the imaging device and the photosensor with respect to the substrate and the positioning accuracy between the imaging device and the photosensor Can be increased.

  Further, in the present invention according to the above invention, the rotating member includes a cylindrical rotor and a magnet that is fitted in the rotor and in which N poles and S poles are alternately arranged in the circumferential direction. The stator member which has a coil part is arrange | positioned on the outer side of this, The said rotation member forms a part of hollow motor, It is characterized by the above-mentioned. In the present invention configured as described above, since the rotating member that drives the lens barrel that moves the lens in the optical axis direction forms a part of the hollow motor, the number of components can be reduced.

  According to the present invention, in the above invention, threaded portions that are screwed to each other are formed on the inner peripheral surface of the rotor and the outer peripheral surface of the lens barrel, and the lens is rotated as the rotor rotates. And screwing in the direction of the optical axis via the respective screw portions. In the present invention configured as described above, the lens is moved in the optical axis direction via the lens barrel by screwing the screw portion formed on the inner peripheral surface of the rotor and the screw portion formed on the outer peripheral surface of the lens barrel. Thus, high positioning accuracy of the lens can be ensured.

  The present invention is characterized in that, in the above invention, the reflection region is formed corresponding to each of the initial position of the lens and the movement end position of the lens. According to the present invention configured as described above, a photo sensor having a pair of light projecting unit and light receiving unit can detect an end position which is a limit position of movement from the initial position of the lens, together with the initial position of the lens. The detection mechanism can be simplified.

  Further, the present invention is characterized in that, in the above invention, a stop member is provided that restricts the rotation of the rotation member and restricts the movement of the lens to a region other than the use region. In the present invention configured as described above, the movement of the lens to a region other than the use region can be prevented by the stop member.

  According to the present invention, in the above invention, the stop member is one protrusion formed on the fixed member, and the protrusion is rotated in one direction with the rotation of the rotation member in one direction. A first abutting portion that abuts on the moving member, and a second abutting portion that abuts on the rotating member in accordance with a rotating operation in a direction opposite to the one direction, and the reflection region is The rotation member and the first contact portion are formed in relation to the contact position between the rotation member and the second contact portion. According to the present invention configured as described above, the movement of the lens in the direction of further returning from the initial position can be restricted by the one protrusion having the first contact portion and the second contact portion, and from the initial position. The movement of the lens in the direction beyond the end position, which is the limit position of movement, can be restricted, and the configuration in which the lens is held in the use region between the initial position and the end position is simplified.

  The present invention includes a reflection area provided on the end face of the rotating member, and a photosensor that is disposed so as to face the reflection area and includes a pair of light projecting parts and light receiving parts. The initial position of the lens can be detected by the sensor, and the size in the direction orthogonal to the optical axis direction can be suppressed. This makes it possible to reduce the size of the device, which has been difficult in the past.

  The best mode for carrying out a lens driving device according to the present invention will be described below with reference to the drawings.

[Configuration of this embodiment]
1 is an external perspective view of an embodiment of a lens driving device according to the present invention, FIG. 2 is a rear view showing the base shown in FIG. 1 except for the base, and FIG. FIG. 4 is a longitudinal sectional view of the present embodiment, FIG. 5 is a perspective view showing the arrangement relationship of the rotor, the reflection region, and the photosensor provided in the present embodiment, and FIG. 6 is the present embodiment. It is a perspective view which shows the magnet provided.

  As shown in FIGS. 1 and 4, the present embodiment is formed on a base 2 connected to a substrate, for example, a printed circuit board 1, a chassis 3 mounted on the base 2, and an upper portion of the chassis 3. And a top guide 4 which is fitted into the hole and forms the upper part.

  As shown in FIGS. 3 and 4, a stator member 5 is disposed in an internal space formed by the base 2, the chassis 3, and the top guide 4, and the stator member 5 is, for example, at a lower position. The first coil unit 6 is provided with a second coil unit 7 at the upper position. As shown in FIGS. 1 and 2, terminal pins 6 a and 6 b are connected to both ends of the first coil portion 6, and terminal pins 7 a and 7 b are connected to both ends of the second coil portion 7, respectively. .

  Inside the stator member 5 are housed a rotor 8 and a magnet 9 that is fitted into the rotor 8 and in which N poles and S poles are alternately arranged in the circumferential direction. The rotor 8 and the magnet 9 constitute a rotating member formed in a cylindrical shape. Further, a stepping motor, for example, a hollow motor, that can be rotated forward and backward is formed by the rotating member composed of the rotor 8 and the magnet 9 and the stator member 5 having the first coil portion 6 and the second coil portion 7 described above. A cropole motor is configured.

  Inside the rotor 8, a screw portion 12 a that is screwed with a screw portion 8 a formed on the inner peripheral surface of the rotor 8 is formed on the outer periphery, and a lens barrel 12 that can move in the optical axis direction as the rotor 8 rotates is provided. It is arranged. On the inner side of the lens barrel 12, a screw portion 11 a that is screwed with a screw portion 12 b formed on the inner peripheral surface of the lens barrel 12 is provided on the outer peripheral surface, and the lens 10 is held, and light is integrated with the lens barrel 12. A holding member 11 that moves in the axial direction is arranged.

  A groove 12c is formed at the upper end of the lens barrel 12 described above, and a guide protrusion 4a that protrudes downward and is relatively movable in the groove 12c is formed on the top guide 4. The groove 12c and the guide projection 4a allow the lens barrel 12 to move in the optical axis direction without rotating through the screw portions 8a and 12a when the rotor 8 rotates.

  In this embodiment, in particular, as shown in FIG. 6, a reflection region 13 made of white ink or silver tape having a high light reflectance is formed on the lower end surface 9 a of the magnet 9. Surface portions other than the reflective region 13 of the lower end surface 9a of the magnet 9 are non-reflective regions 14 such as unprocessed or black-processed with low light reflectivity.

  Moreover, as shown in FIGS. 3-5, it arrange | positions so that the reflective area | region 13 formed in the lower end surface 9a of the magnet 9 can be opposed, and the photo sensor 15 which consists of a pair of light projection part 15a and the light-receiving part 15b is provided. . This photosensor 15 is mounted on the printed circuit board 1 described above. Note that the image sensor can also be mounted on the same printed circuit board 1.

  The reflection region 13 and the photosensor 15 described above constitute stop position detecting means for detecting the rotation stop position of the magnet 9 and the rotor 8 forming the rotation member, that is, the stop position.

  The reflection region 13 formed on the lower end surface 9a of the magnet 9 described above is the start end portion 13a corresponding to the initial position of the lens 10 and the limit position of the movement of the lens 10 in the optical axis direction, as shown in FIG. The terminal part 13b corresponding to the terminal position is included.

  FIG. 7 is a diagram for explaining the engagement relationship between the protrusion formed on the upper end surface of the magnet provided in this embodiment and the protrusion formed on the back surface of the top guide of this embodiment. Is a plan view of the magnet, and FIG. 5B is a back view of the top guide.

  As shown in FIG. 7A or FIG. 6 described above, the upper end surface 9b of the magnet 9 is provided with a protruding portion 9c protruding upward, and as shown in FIG. 7B, On the back surface of the top guide 4, there is provided a protruding portion 4 b that restricts the movement of the lens 10 to a region other than the use region by abutting against the protrusion 9 c of the magnet 9 to restrict the rotation operation of the magnet 9. .

  Only one protrusion 4b is formed on the top guide 4, and excessive rotation of the magnet 9 and the rotor 8 in one direction, that is, the movement of the lens 10 upward in FIG. Along with the excessive rotation operation, the first contact portion 4b1 that contacts the projection 9c of the magnet 9 and the excessive rotation operation of the magnet 9 and the rotor 8 in the direction opposite to the one direction described above, that is, the lens 4 is provided with a second abutting portion 4b2 that abuts against the protruding portion 9c of the magnet 9 as the rotor 9 moves excessively.

  The end portion 13b of the reflection region 13 shown in FIG. 6 formed on the lower end surface 9b of the magnet 9 and the first contact portion 4b1 of the protrusion 4b of the top guide 4 are provided in association with each other. 13 start end portions 13a and the second contact portions 4b2 of the protruding portions 4b of the top guide 4 are provided in association with each other.

  FIG. 8 is a block diagram showing the main configuration of the motor control means provided in this embodiment. FIG. 9 shows the relationship between the preset lens control position and the photosensor signal output, and the lens control position and the hollow motor. It is a figure which shows the relationship with the control signal S which controls the drive of No ..

  In the present embodiment, the four different energization modes to the first coil portion 6 and the second coil portion 7 described above are set as one set, and the one set is repeated to replace the rotating member, that is, the magnet 9 and the rotor 8 with the lens 10. Rotate in one direction to move away from the initial position, i.e., move upward in FIG. 4, or to move the lens 10 back to the initial position, i.e., move downward in FIG. Motor control means 20 for rotating in the other direction opposite to the one direction is provided. When the motor control unit 20 rotates the magnet 9 and the rotor 8 in the other direction to return the lens 10 to the initial position, the motor control unit 20 uses the stop position detection unit including the reflection region 13 and the photosensor 15 to detect the stop position. When the start end 13a of the region 13 is detected, the magnet 9 and the rotor 8 are returned by one step in one direction opposite to the other direction described above, and the position returned by one step becomes the initial position of the lens 10. The control signal S for controlling the driving of the hollow motor is output.

  As shown in FIG. 8, the motor control means 20 performs an after-mentioned process in accordance with, for example, an input unit 20a for inputting an output from the photosensor 15 and a signal from the photosensor 15 input to the input unit 20a. An arithmetic unit 20b, an output unit 20c that outputs a control signal S corresponding to the processing result in the arithmetic unit 20b to each terminal pin 6a, 6b, 7a, 7b of the hollow motor, and a control signal output from the output unit 20c A storage unit 20d that temporarily stores S is included.

  In this embodiment, as shown in FIG. 9, the rotational position of the magnet 9 and the rotor 8 of the hollow motor controlled by the control signal S of the motor control means 20, that is, the control position of the lens 10, for example, from 0 to 34. Are set at 35 positions. The control signal S includes four energization modes “1” to “4”.

  For example, in the energization mode of S = 1, the value A1 of the signal given to the terminal pin 6a of the first coil section 6 is 1 (high level), the value A2 of the signal given to the terminal pin 6b is 0 (low level), In this configuration, the value B1 of the signal applied to the terminal pin 7a of the second coil section 7 is 0 (low level) and the value B2 of the signal applied to the terminal pin 7b is 0 (low level). That is, when S = 1, the control signal S in which (A1, A2, B1, B2) is (1, 0, 0, 0) is output to the hollow motor.

  The energization mode of S = 2 is an energization mode in which (A1, A2, B1, B2) is (0, 0, 1, 0), and the energization mode of S = 3 is (A1, A2, B1). , B2) is (0, 1, 0, 0), and the energization mode of S = 4 is that (A1, A2, B1, B2) is (0, 0, 0, 1). It is a form. The control signals S (= 1 to 4) having these four different energization forms are configured in one set and correspond to the four control positions. This set of control signals S (= 1 to 4) is repeatedly output to the hollow motor, and the rotational position of the magnet 9 and the rotor 8 of the hollow motor, that is, the control position of the lens 10 is 0 shown in FIG. To 34 corresponding positions. The initial position of the lens 10 is a control position 0 controlled by a control signal S (= 2) in which the energization mode (A1, A2, B1, B2) is (0, 0, 1, 0). The terminal position which is the limit position of the movement of 10 is the control position 34 controlled by the control signal S (= 4) in which the energization form (A1, A2, B1, B2) becomes (0, 0, 0, 1). It has become.

  Further, as shown in FIG. 9, a preliminary control position ST1 on the end position side is set at a position exceeding the control position 34 by one step. For example, when the preliminary control position ST1 is reached, the magnet 9 described above is set. The protruding portion 9c comes into contact with the first contact portion 4b1 of the protruding portion 4b of the top guide 4. Further, a preliminary control position ST2 on the initial position side is set at a point one step further back from the control position 0. For example, when the preliminary control position ST2 is reached, the protrusion 9c of the magnet 9 is moved to the top guide 4. The protrusion 4b comes into contact with the second contact portion 4b2. In FIG. 9, “indeterminate” means that the light emitted from the contact portion 15a of the photosensor 15 passes through the boundary line between the reflective region 13 and the non-reflective region 14 shown in FIG. Therefore, it is shown that the output is 0 or 1 or is not stable.

[Operation of this embodiment]
FIG. 10 is a view for explaining the positional relationship between the reflection area provided on the lower end surface of the magnet provided in the present embodiment and the photosensor. FIG. 10A is a view showing a state at the time of photographing a subject, FIG. Is a diagram showing a state in the middle of returning the lens to the initial position, FIG. 11C is a diagram showing a state when the lens has reached the stop position, and FIG. 11 is a process in the arithmetic unit included in the motor control means shown in FIG. It is a flowchart which shows a procedure.

  For example, when the control signal S is output from the output unit 20c of the motor control means 20 to the hollow motor in the state where the lens 10 is held at the initial position, that is, the control position 0 in FIG. 9, this hollow motor is configured. The rotating member, that is, the magnet 9 and the rotor 8 rotate in one direction described above. As the rotor 8 rotates in one direction, the lens barrel 12 moves upward through the screw portions 8a and 12a, and the holding member 11, that is, the lens 10 moves upward together with the lens barrel 12. Moving. During this time, the control signal S is sequentially output so that S = 2 to S = 3, 4 and then sequentially output so that S = 1 to 4, and thereafter, one set of S = 1 to 4 is the subject. Is repeatedly given to the hollow motor according to the focal length of the lens 10 with respect to the lens. When the control position corresponding to the focal length is reached, the output of the control signal from the motor control means 20 is stopped, and a desired subject is photographed.

  Further, during this period, as the magnet 9 constituting the rotating member rotates in the direction of the arrow 21 in FIG. 6, the output of the photosensor 15 changes from “1” to “0” as shown in FIG. Here, if the lens 10 moves to the preliminary control position ST1 shown in FIG. 9 beyond the control position 34 that is the movement end position, the end portion 13b of the reflection region 13 shown in FIG. As a result, the output of the photosensor 15 becomes “1”, and the motor control means 20 sets the control signal S to S = 4 and returns the lens 10 one step from the preliminary control position ST1 to the control position 34, where The output of the control signal S is stopped. Further, during this time, when the lens 10 moves to the preliminary control position ST1, the protrusion 9c provided on the upper end surface 9b of the magnet 9 shown in FIG. 7A is a top guide shown in FIG. 7B. 4 abuts on the first abutting portion 4b1 of the projecting portion 4b, and thereby further rotation of the magnet 9 and the rotor 8 is restricted.

  On the other hand, the control in the case where the lens 10 is held at any control position and the subject is photographed and then returned from the control position to the initial position, that is, the initial position return control of the lens 10 is shown in the flowchart of FIG. It is done by processing. The processing of the flowchart of FIG. 11 is mainly performed by the arithmetic unit 20b of the motor control means 20.

  Here, as an example, the case where the lens 10 is returned to the initial position from the state where the lens 10 is held stationary at the control position 13 shown in FIG. 9 will be described.

  When the lens 10 is returned to the initial position, as shown in step S1 of FIG. 11, the calculation unit 20b of the motor control unit 20 confirms what the value of S of the control signal immediately before the lens 10 stops. Is performed by the control signal S stored in the storage unit 20d. Now, the control signal immediately before the lens 10 is held stationary is S = 3, and the control position where the lens 10 is held stationary is confirmed as the control position 13 shown in FIG. A control signal S of the form (0, 1, 0, 0) is output to the hollow motor.

Next, as shown in step S3, the value “3” of the control signal S that has just been transmitted is temporarily stored in the storage unit 20d, and then the process proceeds to step S4 to perform an operation for decrementing the value of S by one. . now,
S = 3-1 = 2.

  Next, the process proceeds to step S5, and it is determined whether or not the value of S is 0. Now, since S = 2 and it is not 0, it is determined to be no, and the process returns to step S2, and the control signal S of the energization mode (0, 0, 1, 0) of S = 2 is output to the hollow motor. Thereby, the magnet 9 and the rotor 8 constituting the rotating member are rotated in the other direction opposite to the above-described one direction, that is, in the direction opposite to the arrow 21 in FIG. 6, and the lens 10 is in the control position in FIG. 12 is returned.

Next, in step S3, the storage in the storage unit 20d is rewritten from S = 3 to S = 2, and in step S4
S = 2-1 = 1
Is calculated.

Next, the process proceeds to step S5, where it is determined whether S is 0 or not. Now, since S = 1 and not 0, it is determined as no, and the process returns to step S2 again, and the control signal S of the energization mode (1, 0, 0, 0) of S = 1 is output to the hollow motor. Thereby, the lens 10 is returned to the control position 11 of FIG. In step S3, the storage in the storage unit 20d is rewritten from S = 2 to S = 1. In step S4,
S = 1-1 = 0
Is calculated.

  Next, the process proceeds to step S5, where it is determined whether S is 0 or not. Now, the position signal is 0, and it is determined as YES, and the process proceeds to step S6. In step S6, the position signal from the photosensor 15 is captured. Now, the output “0” from the photosensor 15 corresponding to the control position 11 is captured.

  Next, the process proceeds to step S7, and it is determined whether or not the position signal is “0”. Since S = 0 at this time, it is determined as YES and the process proceeds to step S8. In step S8, S = 4 is set, and the process returns to step S2. In step S2, a control signal S of S = 4 energization mode (0, 0, 0, 1) is output to the hollow motor. As a result, the lens 10 is returned to the control position 10 in FIG.

  During this time, the positional relationship between the reflection region 13 provided on the lower end surface 9a of the magnet 9 and the photosensor 15 changes from the relationship shown in FIG. 10A to the relationship shown in FIG.

  Thereafter, the same processing and operation are repeated, and the start end portion 13a of the reflection region 13 provided on the lower end surface 9a of the magnet 9 reaches the stop position on the photosensor 15 as shown in FIG. When the lens 10 moves beyond the initial control position 0 to the preliminary control position ST2 shown in FIG. 9, the control signal S at this time becomes S = 1.

Therefore, the calculation of step S4 in FIG.
S = 1-1 = 0
Thus, the determination in step S5 is YES, and the position signal from the photosensor 15 is captured in step S6. During this time, the light emitted from the light projecting unit 15a of the photosensor 15 is reflected by the reflection region 13 and input to the light receiving unit 15b, and the output from the photosensor 15 becomes “1”. When the output “1” from the photosensor 15 is input to the calculation unit 20b via the input unit 20a of the motor control means 20, the determination in step S7 in FIG. 11 is no and the process proceeds to step S9.

  In this procedure S9, the control signal S of the energization mode (0, 0, 1, 0) of S = 2 is output to the hollow motor. As a result, the magnet 9 and the rotor 8 constituting the rotating member are returned one step again from the other direction so far, that is, in the direction of the arrow 21 in FIG. 6, and the lens 10 is moved from the preliminary control position ST2 in FIG. One step is returned to the control position 0, that is, the initial position. Here, the output of the control signal S stops.

  While such an operation is performed, when the lens 10 moves to the preliminary control position ST2, the protrusion 9c provided on the upper end surface 9b of the magnet 9 shown in FIG. It abuts on the second abutting portion 4b2 of the protruding portion 4b of the top guide 4 shown in the figure, and thereby further rotation of the magnet 9 and the rotor 8 is restricted.

[Effect of this embodiment]
According to the present embodiment configured as described above, the mechanism for detecting the initial position of the lens 10 is configured such that the reflection region 13 provided on the lower end surface 9a of the magnet 9 constituting the rotating member and the reflection region 13 are opposed to each other. The photosensor 15 can be configured by a pair of light projecting portions 15a and light receiving portions 15b. That is, the reflecting region 13 formed on the lower end surface 9a of the magnet 9 and the photosensor 15 including the light projecting portion 15a and the light receiving portion 15b are extended on the outer peripheral surface of the magnet 9 in a direction perpendicular to the optical axis direction. The initial position of the lens 10 can be detected without providing a special member. Thereby, the dimension in the direction orthogonal to the optical axis direction can be suppressed, and the apparatus can be downsized.

  Further, when the image sensor and the photosensor 15 are provided on the same printed circuit board 1, the positioning accuracy of the image sensor and the photosensor 15 with respect to the printed circuit board 1 and the positioning accuracy between the image sensor and the photosensor 15 are increased. be able to.

  Further, in this embodiment, the rotating member that drives the lens barrel 12 that moves the lens 10 in the optical axis direction, that is, the magnet 9 and the rotor 8 form a part of the hollow motor, so that the number of parts is reduced. Can contribute to reducing production costs.

  In the present embodiment, the lens 10 is moved in the optical axis direction via the lens barrel 12 by screwing the screw portion 8a formed on the inner peripheral surface of the rotor 8 and the screw portion 12a formed on the outer peripheral surface of the lens barrel 12. Since the lens 10 is moved, i.e., screwed, high positioning accuracy of the lens 10 can be secured.

  In the present embodiment, the detection position of the lens 10 is detected by the photosensor 15 having the pair of light projecting portions 15a and the light receiving portion 15b, that is, the control position 0 shown in FIG. 9, that is, the control position 34 shown in FIG. 9 can be detected, and the mechanism for detecting the end position is simplified, which also contributes to the reduction of manufacturing costs.

  In the present embodiment, the protrusions 4 b provided on the top guide 4 can prevent the lens 10 from moving outside the use area. That is, when the lens 10 is about to move beyond the terminal position of one protruding portion 4b, the lens 10 is moved beyond the first contact portion 4b1 that restricts the movement of the lens 10 and beyond the initial position. Since the second contact portion 4b2 for restricting the movement of the lens 10 is provided, the configuration for holding the lens 10 in the use region between the initial position and the end position is simplified. Contributes to reducing production costs.

  Further, in the present embodiment, four different energization modes {A1, A2, B1, B2} = {(1, 0, 0, 0) (0, 0, 1, 0) (0, 1, 0, 0) (0, 0, 0, 1)} is set as one set, and the one set is repeated to form a rotating member. When the hollow motor is controlled to rotate the magnet 9 and the rotor 8 in the direction in which the lens 10 returns to the initial position, [1] is output from the photosensor 15 and corresponds to the start end 13 a of the reflection region 13. When the stop position is detected, the lens 10 is always returned by one step in the direction opposite to the other direction described above, whereby the lens 10 is returned from the preliminary control position ST2 shown in FIG. 9 to the control position 0. The control position 0 is the initial position of the lens 10. Accordingly, the lens 10 can be returned to the control device 0 shown in FIG. 9, that is, the initial position by the control of the hollow motor of the motor control unit 20 without being affected by the backlash, and the accuracy without causing the deviation of the initial position. The initial position return control of the lens 10 having a high height can be realized, and excellent performance can be ensured.

1 is an external perspective view of an embodiment of a lens driving device according to the present invention. It is a back view shown except a base from the state shown in FIG. It is the perspective view which fractured | ruptured and showed substantially half from the state shown in FIG. It is a longitudinal cross-sectional view of this embodiment. It is a perspective view which shows the arrangement | positioning relationship of the rotor with which this embodiment is provided, a reflective area | region, and a photosensor. It is a perspective view which shows the magnet with which this embodiment is equipped. It is a figure explaining the engagement relationship of the projection part formed in the upper end surface of the magnet with which this embodiment is provided, and the projection part formed in the back surface of the top guide of this embodiment, (a) A figure is a magnet. The top view and (b) are back views of the top guide. It is a block diagram which shows the principal part structure of the motor control means with which this embodiment is equipped. It is a figure which shows the relationship between the control position of a lens set beforehand and the signal output of a photo sensor, and the relationship between the control position of a lens and the control signal S which controls the drive of a hollow motor. 2A and 2B are views for explaining the positional relationship between a reflection region provided on the lower end surface of a magnet provided in the present embodiment and a photosensor, in which FIG. 1A shows a state at the time of photographing a subject, and FIG. The figure which shows the state in the middle of returning to an initial position, (c) A figure is a figure which shows a state when a lens has reached the stop position. It is a flowchart which shows the process sequence in the calculating part contained in the motor control means shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printed circuit board 2 Base 3 Chassis 4 Top guide 4a Guide protrusion 4b Protrusion part (stop member)
4b1 1st contact part 4b2 2nd contact part 5 Stator member (hollow motor)
6 1st coil part 6a Terminal pin 6b Terminal pin 7 2nd coil part 7a Terminal pin 7b Terminal pin 8 Rotor (rotating member) [hollow motor]
8a Screw part 9 Magnet (rotating member) [Hollow motor]
9a Lower end surface 9b Upper end surface 9c Projection portion 10 Lens 11 Holding member 11a Screw portion 12 Lens barrel 12a Screw portion 12b Screw portion 12c Groove portion 13 Reflection region (stop position detection means)
13a start end 13b end 14 non-reflective area 15 photo sensor (stop position detecting means)
15a Emitting unit 15b Receiving unit 20 Motor control means 20a Input unit 20b Arithmetic unit 20c Output unit 20d Storage unit

Claims (7)

A rotation member formed in a cylindrical shape and a lens barrel that moves the lens in the optical axis direction as the rotation member rotates,
A reflection region provided on an end surface of the rotating member, and a photosensor that is disposed to be opposed to the reflection region and includes a pair of light projecting units and a light receiving unit,
A lens driving device that detects an initial position of the lens by receiving light of the light projecting unit through the reflection region by the light receiving unit. In the invention of claim 1,
A lens driving device comprising: an imaging device mounted on a substrate positioned below the lens barrel; and the photosensor mounted on the substrate. In the invention according to claim 1 or 2,
The rotating member is composed of a cylindrical rotor and a magnet that is fitted into the rotor and in which N poles and S poles are alternately arranged in the circumferential direction.
A stator member having a coil portion is disposed outside the rotating member,
The lens driving device according to claim 1, wherein the rotating member forms part of a hollow motor. In the invention of claim 3,
Each of the inner peripheral surface of the rotor and the outer peripheral surface of the barrel is formed with a threaded portion that is screwed together,
The lens driving device according to claim 1, wherein the lens is screwed in the optical axis direction through the respective screw portions as the rotor rotates. In the invention of claim 1,
The lens driving device according to claim 1, wherein the reflection region is formed corresponding to each of the initial position of the lens and a movement end position of the lens. In the invention of claim 1,
A lens driving device comprising: a stop member that restricts the rotation of the rotation member and restricts movement of the lens to a region other than a use region. In the invention of claim 6 above,
The stop member is one protrusion formed on the fixing member,
The protrusion includes a first abutting portion that comes into contact with the rotating member in accordance with a rotating operation in one direction of the rotating member, and a rotating operation in another direction opposite to the one direction. And a second abutting portion that abuts the rotating member,
The reflection region is formed in relation to a contact position between the rotating member and the first contact portion and a contact position between the rotating member and the second contact portion. Lens drive device.

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