JP2006091262A - Lens driving device, imaging apparatus and optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens driving device realizing the decrease in power consumption by making a lens holder fit in a cylindrical rotor easily move in the rotary shaft direction of the rotor. <P>SOLUTION: A lens unit has a front cover 25 where a slot 25b is formed, the lens holder 22 where a projected line part 22a engaged with the slot 25b and pins 22b are formed, a helicoid barrel 38 where a helicoid 38a engaged with the pins 22b is formed, the cylindrical rotor 33 inside which the helicoid barrel 38 is arranged and which has a magnet part on its outer circumference, and 1st and 2nd stators 30 and 31 which are formed in ring shape so as to form a fixed void between the magnet part and the stators. A two-phase PM type stepping motor is constituted of the 1st and the 2nd stators 30 and 31 and the rotor 33. When the 1st and the 2nd stators 30 and 31 are energized and the rotor 33 is rotated, the lens holder 22 moves in an optical axis direction through three pins 22b engaged with the helicoid 38a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention includes a lens driving device that has a rotating cylinder that rotates together with the rotor in the rotor, and moves a lens holder disposed in the rotating cylinder in the direction of the rotation axis, and a photographing apparatus and an optical device equipped with the lens driving device. It is about.

  Currently, photographing apparatuses that acquire image data based on image signals from an image sensor such as a CCD image sensor are rapidly spreading. The photographing device is equipped with a battery, which allows photographing freely even outdoors. In particular, a camera-equipped cellular phone that is a photographing device having a telephone function is provided with a particularly small lens driving device, and recently, a camera-equipped cellular phone having an autofocus function and an optical zoom function has also appeared.

  In an imaging device with an autofocus function, a lens driving device that moves the imaging lens in the optical axis direction for focusing is provided, and various lens driving devices have been devised at present. For example, a male helicoid is provided on the outer periphery of a cylindrical lens holder that holds a photographing lens, a female helicoid that engages with the male helicoid is formed on the inner periphery of the fixed cylinder, and the male helicoid is aligned with the female helicoid. There is a lens driving device that moves the photographing lens in the optical axis direction together with the lens holder by inserting the lens in a fixed cylinder and rotating the lens holder with a motor via a gear or the like.

  By the way, in the lens driving device as described above, a gear, a motor, and the like must be provided in the vicinity of the lens holder, and the structure becomes complicated. In a small photographing device such as a camera-equipped mobile phone, such a lens is used. In some cases, it is difficult to secure a space for installing the drive device. Therefore, a cylindrical stator that forms a magnetic field in response to current supply, a magnet that is formed in a cylindrical shape and is alternately magnetized in the direction of making a round around the outer periphery, and a magnet that is magnetized in the S magnetic pole And a rotor that is rotatably fitted in the stator, a cylindrical shape with a female helicoid formed on the inner periphery thereof, a rotating cylinder that is positioned in the rotor and rotates with the rotor, and a cylindrical shape The lens holder is formed with a male helicoid that engages with the female helicoid on the outer periphery thereof, and when the rotating cylinder rotates, the lens holder is not rotated together with the rotating cylinder but moved only in the direction of the rotation axis. A lens driving device having a guide mechanism has been devised. In this lens driving device, the rotor is fitted into the stator so that the inner circumference of the stator and the outer circumference of the rotor are spaced apart from each other to form a stepping motor, and the lens is arranged so that the male helicoid is engaged with the female helicoid. When the holder is inserted into the rotating cylinder, current is supplied to the stator and the rotor rotates, the rotating cylinder rotates as the rotor rotates, and the lens holder moves in the direction of the rotation axis of the rotating cylinder. . As a result, it is possible to reduce the size of the lens driving device by omitting a transmission mechanism such as a gear, and by further omitting the transmission mechanism, the lens holder can be moved more directly in the optical axis direction. Could be located.

  However, if a female helicoid is formed on the inner periphery of the rotating cylinder and a male helicoid having a plurality of turns is formed on the outer periphery of the lens holder fitted into the rotating cylinder, it occurs at the contact portion between the female helicoid and the male helicoid. The friction is large and the power consumption when moving the lens holder in the direction of the rotation axis has increased. In particular, when the lens driving device is provided in a portable photographing device, the lens holder is mounted on the photographing device because of the power consumption accompanying the movement of the lens holder when the lens holder is moved at a high speed or continuously for a long time. Battery usage time may be shortened.

  In addition, grease is applied to the contact area between the female helicoid and the male helicoid to suppress or absorb the frictional heat generated between the female helicoid and the male helicoid, but the contact area between the female and male helicoids If it is larger, the contact portion with the grease also becomes larger, and the movement of the lens holder is hindered by the viscosity of the grease, which may increase the power consumption during driving. In addition, if the contact portion between the female helicoid and the male helicoid is large, the frictional heat generated from the contact portion also increases, which may cause the grease to deteriorate quickly and make it difficult to move the lens holder. In particular, when helicoids and screws are formed of highly heat-insulating plastic, the burden on the grease becomes greater, and the deterioration of the grease is further accelerated.

  In general, a PM (Permanent Magnet) type stepping motor can be manufactured at a lower cost than an HB (Hybrid) type or VR (Variable Reluctance) type stepping motor, but a smaller torque than an HB type or VR type stepping motor. For this reason, for example, since a plurality of lenses are held, it may be difficult to move a heavy lens holder in the direction of the rotation axis, thereby forming an optical system with high resolution capability. There was something I couldn't do.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the power consumption by facilitating movement of the lens holder fitted to the cylindrical rotor in the direction of the rotation axis of the rotor. The present invention also provides an imaging apparatus and optics that are equipped with such a lens driving device so that the battery can be used for a longer time.

  In order to achieve the above object, in the lens driving device of the present invention, a stator that forms a magnetic field in response to current supply, and a cylindrical shape that is provided with a permanent magnet on its outer periphery, is rotatably fitted in the stator. A stepping motor that is rotated by a magnetic field formed in the stator, a cylindrical shape that has a helicoid formed on its inner periphery, and that is positioned in the rotor and rotates together with the rotor, and a cylindrical shape The lens is held so that it has an optical axis from one end to the other end, a plurality of protrusions that engage with the helicoid are formed on the outer periphery, and the protrusion is fitted into the rotating cylinder so as to engage with the helicoid And a linear guide mechanism that moves the lens holder forward and backward in the direction of the optical axis in accordance with the rotation of the rotary cylinder.

  Further, the number of projections is three, the angles between the projections are equal, and the lens holder is formed so as to be positioned in one turn of the helicoid when fitted into the rotor.

  In addition, a stator that forms a magnetic field in response to current supply, and a cylindrical magnet that is provided with a permanent magnet on the outer periphery thereof, is rotatably inserted into the stator to form a stepping motor, and a magnetic field formed in the stator A rotor that is rotated by a cylinder, a helicoid is formed on the inner periphery of the rotor, a rotating cylinder that is positioned in the rotor and rotates with the rotor, and an optical axis that is formed in a cylindrical shape from one end to the other. A lens holder that holds the lens so as to engage with a substantially one-turn portion of the helicoid, and a lens holder that is fitted into the rotating cylinder so that the screw engages with the helicoid; And a linear guide mechanism for moving the lens holder forward and backward in the optical axis direction according to the rotation.

  Moreover, the screw thread is formed intermittently in a direction that goes around the outer periphery.

  In addition, the photographing apparatus of the present invention includes the lens driving device as described above.

  The optical device according to the present invention includes the lens driving device as described above.

  According to the lens driving device of the present invention, a stator that forms a magnetic field in response to a current supply, and a cylindrical shape that is provided with a permanent magnet on the outer periphery thereof, is rotatably inserted into the stator to constitute a stepping motor. And a rotor that is rotated by a magnetic field formed in the stator, a cylindrical shape having a helicoid formed on the inner periphery thereof, a rotating cylinder that is positioned in the rotor and rotates together with the rotor, and a cylindrical shape that has one end A lens holder that holds the lens so that it has an optical axis from the other end to the other end, a plurality of protrusions that engage with the helicoid are formed on the outer periphery, and a lens holder that fits into the rotating cylinder so that the protrusions engage with the helicoid, and rotation By having a linear guide mechanism that moves the lens holder forward and backward in the direction of the optical axis according to the rotation of the tube, friction is reduced by engaging the projection with the helicoid Bets can be, thereby making it possible to reduce the power consumption for moving the lens holder. In addition, generation of frictional heat can be suppressed and deterioration of grease can be suppressed, and the performance of the lens driving device can be maintained for a longer time.

  Also, there are three protrusions, the angle between the protrusions is equal, and the lens holder is formed so that it is positioned within one helicoid turn when fitted into the rotor. The number of helicoids to be wound can be reduced, the manufacturing cost can be reduced, and the lens holder can be stably moved in the optical axis direction.

  In addition, a stator that forms a magnetic field in response to current supply, and a cylindrical magnet that is provided with a permanent magnet on the outer periphery thereof, is rotatably inserted into the stator to form a stepping motor, and a magnetic field formed in the stator A rotor that is rotated by a cylinder, a helicoid is formed on the inner periphery of the rotor, a rotating cylinder that is positioned in the rotor and rotates with the rotor, and an optical axis that is formed in a cylindrical shape from one end to the other. A lens holder that holds the lens so as to engage with a substantially one-turn portion of the helicoid, and a lens holder that is fitted into the rotating cylinder so that the screw engages with the helicoid; By having a linear guide mechanism that moves the lens holder forward and backward in the optical axis direction according to rotation, friction is reduced by engaging the screw with the helicoid. Power consumption for moving the holder in the optical axis direction can be reduced. In addition, generation of frictional heat can be suppressed, deterioration of grease can be suppressed, and the performance of the lens driving device can be maintained for a long time. In addition, the manufacturing cost can be reduced by reducing the number of turns of the helicoid.

  Moreover, since the thread is intermittently formed in a direction that goes around the outer periphery, the friction between the helicoid and the thread can be further reduced.

  In addition, by providing the above-described lens driving device in the photographing apparatus, it is possible to reduce the power consumption when the lens driving apparatus is used during photographing and to extend the usage time of the battery of the photographing apparatus.

  Further, by providing the optical device with the lens driving device as described above, power consumption at the time of driving can be reduced, and when using a dry cell or a battery, the usage time can be extended.

  FIG. 1 shows an external perspective view of a camera-equipped mobile phone equipped with the lens driving device of the present invention. The mobile phone (photographing device) 2 includes a communication antenna 4, a reception speaker 5, a liquid crystal panel 7, various operation buttons 9, a transmission microphone 11, and the like. Various menu images and the like are displayed on the liquid crystal panel 7. The operation buttons 9 include an input button for inputting numbers and alphabets, an execution button for executing a command, a cancel button for canceling a command, a cross operation button for performing a selection operation, and the like. .

  FIG. 2 shows a rear view of the mobile phone 2. The mobile phone 2 has a photographing function for forming image data of a subject, and the mobile phone 2 is provided with a lens driving device for forming image data. The lens driving device includes, for example, a lens group G1 including first to third lenses (see FIG. 4) 13 to 15, and the first lens 13 is exposed from the back surface of the mobile phone 2. A battery lid 12 is provided under the first lens 13 to protect the battery for power supply from the outside.

  As shown in the block diagram of FIG. 3, the cellular phone 2 includes a CCD image sensor 35 (see FIG. 4) that outputs an image signal according to the subject imaged by the lens group G <b> 1, and a CCD image sensor 35. The operation of the signal processing circuit 14 for processing the image signal of the image, the image correction circuit 15 for correcting the image data formed by the signal processing circuit 14, the recording memory 16 for recording the image data, and the operation of the liquid crystal panel 7 are as follows. LCD controller 6 to control, autofocus detection circuit (hereinafter referred to as AF detection circuit) 17 to detect the in-focus state, motor controller 18 to control driving of a stepping motor included in a lens driving device 20 described later, CCD image sensor A timing generator 8 for controlling the drive of 35 and a CPU for controlling the overall operation of the mobile phone 2 9 demodulates a wireless signal communication I / F10, etc. to form the data received by the communication antenna 4 together modulates the data to form a radio signal is provided. Further, the mobile phone 2 is provided with a communication port for communicating with an external device such as a computer. By connecting a communication cable to this communication port, the image data recorded in the recording memory 16 is externally provided. Be able to send.

  The mobile phone 2 is provided with an autofocus function for focusing on the subject based on the contrast of the image. When the mobile phone 2 is set to the shooting mode, the AF detection circuit 17 calculates the evaluation value of the in-focus state based on the contrast of the subject image, and the lens driving device operates so that the evaluation value is maximized. In the shooting mode, a through image in which the image of the subject is updated every predetermined time is displayed on the liquid crystal panel 7, and image data is formed when the execution button is pressed when a favorite image is displayed on the liquid crystal panel 7. Is started, and a favorite image is recorded in the recording memory 16 as image data.

  FIG. 4 shows an external perspective view of a lens driving device mounted on the mobile phone 2. The lens driving device 20 is covered with a front cover 25 and a rear cover 26. From the front surface of the front cover 25, the first, second, and third lenses 13, 14, and 15 are arranged in this order from the front side. Of these, the first lens 13 is exposed. The first, second, and third lenses 13, 14, and 15 are held by a lens holder 22, and the first, second, and third lenses 13, 14, and 15 are moved as the lens holder 22 moves in the optical axis direction. The position of is adjusted. By moving the lens holder 22 in the optical axis direction and adjusting the positions of the first, second, and third lenses 13, 14, and 15, the subject is brought into focus and a high-quality image can be acquired.

  FIG. 5 is a perspective sectional view of the lens driving device 20. In addition to the first, second, and third lenses 13, 14, 15, the lens holder 22, the front cover 25, and the rear cover 26, the lens driving device 20 has a ring shape that generates magnetic force when current flows. First stator 30, second stator 31, first and second stators 30, 31 rotatably fitted in rotor 33, CCD image sensor 35, optical low-pass filter (hereinafter referred to as O-LPF) 36, etc. It is composed of

  The front cover 25 has an opening 25a that exposes the first lens 13 to the outside. Slots 25b for moving the lens holder 22 in the optical axis direction are formed at the upper and lower ends of the opening 25a in the figure. As will be described later in detail, the lens holder 22 is prevented from rotating around the optical axis L and guided in the optical axis direction by the slot 25b and the like.

  The lens holder 22 is formed in a cylindrical shape, and the first to third lenses 13 to 15 are arranged in order from the front end to the rear end. The first to third lenses 13 to 15 are held so that the optical axis extends along the direction from the front end to the rear end of the lens holder 22, and the optical axis L formed in this way is an O-LPF 36 or a CCD image. It intersects the sensor 35 vertically. Two protrusions 22 a that engage with slots 25 b formed in the front cover 25 are formed on the outer periphery of the front end of the lens holder 22. A straight guide mechanism that moves the lens holder 22 forward and backward in the optical axis direction is configured by the protrusion 22a and the slot 25b. Three pins (projections) 22b projecting radially from the outer periphery are integrally formed behind the projecting portion 22a.

  The rotor 33 is formed in a cylindrical shape, and a magnet portion is provided on the outer periphery thereof. The magnet unit 39 is composed of a plurality of magnets, and each magnet extends from one end of the rotor 33 toward the other end. In the magnet unit 39, the N pole magnets magnetized to the N poles and the S pole magnets magnetized to the S poles are alternately arranged in a direction that goes around the outer periphery of the rotor 33.

  A helicoid cylinder (rotary cylinder) 38 formed in a cylindrical shape is disposed inside the rotor 33. For example, a helicoid 38 a is formed at a pitch of 0.6 mm on the inner periphery of the helicoid cylinder 38, and the outer periphery of the helicoid cylinder 38 is bonded to the inner periphery of the rotor 33. As a result, the helicoid cylinder 38 rotates with the rotation of the rotor 33.

  Each of the first and second stators 30 and 31 is a claw pole type and is formed in a ring shape, and the rotor 33 is rotatably fitted therein so that the magnet portion of the rotor 33 is separated by a certain gap. The first and second stators 30 and 31 and the rotor 33 constitute a two-phase PM type stepping motor. The first and second stators 30 and 31 include a ring-shaped bobbin (not shown), a coil 40 wound around the bobbin, and two magnetic metal plates (not shown) including the bobbin around which the coil 40 is wound. ) Etc. By supplying a pulse current to the first stator 30 and the second stator 31, an N magnetic pole or an S magnetic pole is formed and the rotor 33 rotates, and the supply timing of the pulse current is controlled by a motor controller (not shown).

  FIG. 6 shows an exploded perspective view of the lens driving device 20. A comb-like claw pole 43 is formed on each of the two magnetic metal plates covering the coil 40. The claw pole 43 formed on one magnetic metal plate is a claw pole formed on the other magnetic metal plate. 43 and the inner circumference of the stator are bent so as to be adjacent to each other with a certain gap. Electric power is supplied to the stators 30 and 31 via lead wires, and when the first and second stators 30 and 31 are energized, the claw pole 43 is excited to the N pole or S pole depending on the direction of current flow. Form magnetic poles. The claw pole 43 of the first stator 30 and the claw pole 43 of the second stator 31 are arranged so as to be shifted by a certain angle.

  In order to rotate the rotor 33, a forward current is passed through the coil in the first stator 30, then a forward current is passed through the coil in the second stator 31, and the reverse direction is applied to the coil in the first stator 30. Current control is repeated such that a current in the reverse direction is passed through the coil in the second stator 31. In this way, by energizing the coils in the first and second stators 30 and 31, the rotor 33 can be rotated by appropriately forming the N magnetic pole and the S magnetic pole. In this example, the first and second stators 30 and 31 are excited one by one and the rotor 33 is rotated. However, the rotor 33 is rotated by the two-phase excitation method in which the respective stators are simultaneously excited. It does n’t matter.

  The lens holder 22 is fitted into the helicoid cylinder 38 so that the pin 22b engages with the helicoid 38a formed on the helicoid cylinder 38, and the protrusion 22a is aligned with the slot 25b formed on the front cover 25 to drive the lens. The device 20 is assembled. Accordingly, when the rotor 33 rotates and the pin 22b slides in the helicoid 38a, the protrusion 22a is guided by the slot 25a, and the lens holder 22 moves forward and backward in the optical axis direction.

  When the lens holder 22 is fitted into the rotor 33, the three pins 22b that are formed to protrude from the outer periphery of the lens holder 22 are positioned within one turn of the helicoid 38a. When the lens holder 22 is observed from the optical axis direction, the pins 22b protrude in the radial direction from the outer periphery of the lens holder 22 every 120 degrees, thereby enabling the lens holder 22 to be stably moved in the optical axis direction. The friction between the lens holder 22 and the helicoid cylinder 38 is reduced to reduce power consumption when the lens holder 22 is moved.

  Next, the operation of the above configuration will be described. When the digital camera 2 is set to the photographing mode, image data of the subject is formed based on the image signal output from the CCD image sensor 35, and the evaluation value of the focused state is calculated based on the contrast of the subject image. A pulse current is supplied from the motor controller 18 to the first and second stators 30 and 31 so that the evaluation value becomes maximum. When a pulse current is supplied from the motor controller 18 to the first and second stators 30 and 31, the rotor 33 rotates, and the lens holder 22 moves back and forth in the optical axis direction according to the rotation of the rotor 33 to focus on the subject. Are matched.

  A helicoid cylinder 38 is bonded to the inner side of the rotor 33, and three pins 22b that engage with the helicoid 38a are formed on the outer periphery of the lens holder 22. When the rotor 33 rotates, the helicoid cylinder 38 rotates accordingly, and the lens holder 22 moves forward and backward in the optical axis direction via the pin 22b. By forming the pin 22b on the lens holder 22, the contact portion between the rotor 33 and the lens holder 22 is reduced, and the resistance received from the grease applied in the helicoid 38a is reduced, so that the lens holder 22 moves more smoothly. Therefore, it is possible to reduce power consumption when moving the lens holder 22. Further, since the contact portion between the lens holder 22 and the rotor 33 is reduced, the generation of frictional heat can be suppressed, and deterioration of the grease applied to the helicoid 38a can be suppressed to maintain the performance of the lens driving device 20 for a longer time. be able to. Further, the stepping motor composed of the first and second stators 30 and 31 and the rotor 33 is a PM type, so that a holding current for holding the rotor position is supplied to the first and second stators 30 and 31. Therefore, the power consumption of the lens driving device 20 can be further reduced, and the usage time of the battery mounted on the mobile phone 2 can be further extended.

  In the above embodiment, the two-phase PM type stepping motor is shown, but the type of the stepping motor is not limited to this. For example, a two-phase HB type stepping motor or a three-phase stepping motor may be configured to drive the lens holder. In particular, by using an HB-type stepping motor, even a heavy lens holder can generate sufficient torque to move it forward and backward, and more easily control the position of the lens holder more finely. Become.

  In the above-described embodiment, the three pins 22b are formed on the outer periphery of the lens holder 22, but a thread that engages with the helicoid may be formed on the outer periphery of the lens holder. As shown in FIG. 7, a screw thread 50 is formed on the outer periphery of the lens holder 22 so as to make one round of the outer periphery of the lens holder 22. The screw thread 50 is formed in accordance with the helicoid 38a, and when the lens holder 22 is fitted into the rotor 33, the screw thread 50 is positioned in a substantially one-turn portion of the helicoid 38a. Thus, by forming the screw thread 50 that engages with the substantially one-turn portion of the helicoid 38a on the outer periphery of the lens holder 22, friction between the rotor 33 and the lens holder 22 is reduced, and the lens holder 22 is moved in the optical axis direction. Power consumption when moving can be reduced. Further, it can be expected that the stability at the time of movement of the lens holder 22 is improved by reducing the number of turns of the helicoid 38a.

  Further, in FIG. 7, the screw thread 50 is provided on the outer periphery of the lens holder 22, but the screw thread may be formed intermittently in a direction that goes around the outer periphery. As shown in FIG. 8, a protruding piece 60 that protrudes intermittently toward the radial direction on the outer periphery of the lens holder 22 may be formed. A plurality of projecting pieces 60 are provided on the outer periphery of the lens holder 22, and when the lens holder 22 is fitted into the rotor 33, the projecting pieces 60 are positioned in a substantially one turn portion of the helicoid 38 a. Thus, by providing the protruding piece 60 on the outer periphery of the lens holder 22, the contact portion between the lens holder 22 and the rotor 33 can be further reduced to reduce friction, and the lens holder 22 is moved in the optical axis direction. Power consumption can be further reduced.

  Further, in the lens driving device 20 illustrated in the above embodiment, the lens holder 22 moves in the optical axis direction by driving the stepping motor including the first and second stators 30 and 31 and the rotor 33, thereby focusing. However, the present invention is not limited to this and may be implemented in a lens driving device having a zoom function. For example, in FIG. 9, a lens holder that holds a zoom lens on the inner circumference of one of the two rotors and a lens holder that holds a focusing lens on the inner circumference of the other rotor. Sectional drawing of the integrated lens drive device is shown. The lens driving device 80 includes a first lens holding frame 82 that holds the first lens group L1, a first lens holder 83 that holds the second lens group L2 for zooming, and a second lens that holds the third lens group L3. The frame includes a holding frame 84, a second lens holder 85 that holds the fourth lens L4 for focusing, and the like. Projection portions 83a and 85a are formed at the front ends of the first and second lens holders 83 and 85, and the rear ends of the first and second lens holding frames 82 and 84 are engaged with the protrusion portions 83a and 85a. Slots 82a and 84a are formed. A first rotor 93 is fitted inside the first and second stators 90 and 91, and a second rotor 97 is fitted inside the third and fourth stators 95 and 96. Helicoid cylinders 98 and 99 are arranged on the inner circumferences of the first and second rotors 93 and 97, respectively, and projections 83b that engage the helicoids 98a and 99a are arranged on the outer circumferences of the first and second lens holders 83 and 85, respectively. , 85b are integrally formed. The respective lens holders 83 and 85 move in the optical axis direction according to the rotation of the first and second rotors 93 and 97. The first and second rotors 93 and 97 are rotated by the magnetic field from the magnetic poles formed on the inner circumferences of the respective stators 90, 91, 95 and 96, and the first, second, third and fourth stators 90 and 91 are rotated. , 95, 96 are controlled by a motor controller (not shown). In this way, a helicoid is formed on the inner periphery, and a zoom function is provided using a helicoid cylinder that rotates with the rotor and a lens holder that has a protrusion positioned on the outer periphery of the helicoid. It can be expected to provide a lens driving device with reduced power consumption during zoom operation.

  In the above embodiment, the linear guide mechanism is configured by the protrusion 22a provided on the lens holder 22 and the slot 25b formed in the front cover 25 so that the protrusion 22a is engaged. The guide mechanism is not limited to this. As shown in FIG. 10, a guide pole 100 is provided along the rotation axis direction of the rotor 33, and a fitting hole 22 c into which the guide pole 100 is fitted is formed in the lens holder 22. Such a guide mechanism can also move the lens holder forward and backward in the rotation axis direction.

  In the above-described embodiment, the present invention is illustrated as implemented on a mobile phone. However, the present invention is not limited to this, and for example, a projection device such as a projector that synthesizes image light from a plurality of primary color lights and projects it onto a screen It can also be used for optical devices such as pickup lens devices such as DVDs, CD-ROMs, MDs, and photographing devices such as digital cameras and silver halide cameras.

It is an external perspective view of a mobile phone. It is an external appearance perspective view which shows the back surface of the mobile telephone which a photographic lens exposes. It is a block diagram of a mobile phone. It is a perspective view of the lens drive device mounted in the mobile phone. It is sectional drawing of a lens drive device. It is a disassembled perspective view of a lens drive device. It is a disassembled perspective view of the lens drive device by which the screw thread was provided in the outer periphery of the lens holder. It is a disassembled perspective view of the lens drive device in which the protrusion piece which protrudes intermittently in the direction which circles an outer periphery is formed in the outer periphery of a lens holder. It is sectional drawing of the lens drive device which can move the lens holder holding the 2nd lens group for zooming, and the lens holder holding the 4th lens for focusing to an optical axis direction. It is sectional drawing of a lens drive device. It is sectional drawing of the lens drive device with which a guide mechanism is comprised by a guide pole and a fitting hole.

Explanation of symbols

2 Mobile phone (photographing device)
13 1st lens 20 Lens drive device 22 Lens holder 22a Projection part 22b Pin (protrusion)
25 Front cover 25a Slot 26 Rear cover 30 First stator 31 Second stator 33 Rotor 38 Helicoid cylinder (rotating cylinder)
38a helicoid 40 coil 50 screw thread 60 protrusion

Claims (6)

A stator that forms a magnetic field in response to a current supply;
A rotor that is cylindrical and has a permanent magnet on its outer periphery, is rotatably fitted in the stator to form a stepping motor, and rotates by a magnetic field formed in the stator;
A rotating cylinder that is cylindrical and has a helicoid formed on its inner periphery, is located within the rotor and rotates with the rotor;
A plurality of protrusions that are formed in a cylindrical shape, hold the lens so as to have an optical axis from one end to the other end, and engage with the helicoid are formed on the outer periphery, and the protrusions engage with the helicoid A lens holder fitted into the rotating cylinder;
A lens drive device comprising: a linear guide mechanism for moving the lens holder forward and backward in the optical axis direction according to the rotation of the rotary cylinder.   The number of the protrusions is three, the angles between the protrusions are equal, and the lens holder is formed so as to be positioned in one turn of the helicoid when fitted into the rotating cylinder. The lens driving device according to claim 1. A stator that forms a magnetic field in response to a current supply;
A rotor that is cylindrical and has a permanent magnet on its outer periphery, is rotatably fitted in the stator to form a stepping motor, and rotates by a magnetic field formed in the stator;
A rotating cylinder that is cylindrical and has a helicoid formed on its inner periphery, is located within the rotor and rotates with the rotor;
A thread is formed on the outer periphery to hold the lens so as to have an optical axis from one end to the other end of the cylinder, and engage with a substantially one-turn portion of the helicoid, and the thread is formed on the helicoid. A lens holder that fits into the rotating cylinder to engage;
A lens drive device comprising: a linear guide mechanism for moving the lens holder forward and backward in the optical axis direction according to the rotation of the rotary cylinder.   The lens driving device according to claim 3, wherein the screw thread is formed intermittently in a direction of making a round of the outer periphery.   An imaging apparatus comprising the lens driving device according to claim 1. An optical device comprising the lens driving device according to claim 1.

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