JP4721679B2 - Lens drive device - Google Patents

Description

  The present invention relates to a lens driving device including a driving source that automatically moves a lens in an optical axis direction, and in particular, a lens applied to a camera mounted on a portable information terminal such as a mobile phone or a portable personal computer. The present invention relates to a driving device.

A camera mounted on a portable information terminal such as a mobile phone or a portable personal computer needs to be as small as possible since the mounting space allowed in the portable information terminal is small. In addition, a lens driving device that moves the lens in the direction of the optical axis is required in order for the camera mounted on the portable information terminal to have an automatic scaling function and an automatic focusing function.
The lens driving device that automatically moves the lens in the optical axis direction includes a lens frame that holds the lens, a cam member that exerts a cam action in the optical axis direction on the lens frame, and a direction in which the cam member is orthogonal to the optical axis direction. Equipped with a gear train composed of a plurality of spur gears, a motor for applying rotational torque to the gear train, a spring for urging the lens frame in the optical axis direction so as to maintain the engagement between the cam member and the lens frame Is known (see, for example, Patent Document 1).
JP-A-11-344326

By the way, in order to incorporate the above-described conventional lens driving device into a narrow mounting space allowed in a portable information terminal, it is necessary to use a motor as small as possible. In addition, since the small motor has a small output torque, it is necessary to increase the reduction ratio of the gear train.
However, if the reduction ratio of a gear train composed of a plurality of spur gears is increased, a large number of spur gears are required. For this reason, it has been difficult to reduce the size so that the lens driving device can be mounted on the portable information terminal.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a narrow mounting mechanism such as a portable information terminal while having a driving mechanism that automatically drives a lens in the optical axis direction. An object of the present invention is to provide a lens driving device for a camera that can be mounted in a space.

The lens driving device of the present invention includes a lens frame having a guide hole that holds the lens and extends in the optical axis direction, and a support shaft that is fitted and inserted into the guide hole to support the lens frame so as to be movable in the optical axis direction. A fixed frame, a spring that urges the lens frame in the optical axis direction, and a drive mechanism that is held by the fixed frame and moves the lens frame in the optical axis direction. A fixed motor, a worm gear fixed to the rotating shaft of the motor, a worm wheel that is rotatably supported by a fixed frame about an axis separated from the optical axis by a predetermined distance and meshes with the worm gear, and a worm wheel Rights and becomes the rotation of the provided and the worm wheel coaxially from a conversion mechanism for transmitting converted into linear motion of the optical axis to the lens frame, springs, including the center axis of the optical axis support shaft It is provided on one side of, and characterized in that.
According to this configuration, when the rotation shaft of the motor is rotated, the rotation is decelerated by the worm gear and the worm wheel, and is converted into a linear movement in the optical axis direction around the axis line by the conversion mechanism and transmitted to the lens frame. The lens frame moves in the optical axis direction. Further, by using a worm gear and a worm wheel for the drive mechanism, the drive mechanism can be reduced in size while ensuring a large reduction ratio. Further, the conversion mechanism converts the rotation of the worm wheel into a straight movement around the axis away from the optical axis and transmits it to the lens frame, so that the drive mechanism can be integrated and the apparatus can be downsized. .
Further, by providing the spring on one side of the plane including the optical axis and the central axis of the support shaft, a moment to tilt the central axis of the guide hole to one side of the plane is always applied to the lens frame. Thus, the contact state between the inner peripheral surface of the guide hole and the outer peripheral surface of the support shaft can be stabilized. Therefore, even if the conversion mechanism is provided coaxially with the worm wheel, the optical axis of the lens frame is wobbled. It is possible to prevent the captured image from changing.

In the above configuration, the conversion mechanism can include a cam that engages with a follower portion formed in the lens frame and includes a cam that rotates with the worm wheel and exerts a cam action in the optical axis direction.
According to this configuration, the conversion mechanism can have a simple structure, and the apparatus can be downsized.

In the above configuration, the lens frame has a protruding arm portion that protrudes radially outward and has a follower portion and a guide hole formed therein, and the support shaft guides the lens frame so as to be movable in the optical axis direction and is a worm wheel. the you rotatably supported, you can adopt a configuration.
According to this configuration, by supporting shaft of the fixed frame in the guide hole of this is inserted fitting to form a guide hole in the projecting arm of the lens frame, made accurately guide the lens frame in the optical axis direction It is possible to prevent the optical axis of the lens frame from wobbling. In addition, it is possible to reduce the size of the apparatus by providing the support shaft with the function of supporting the worm wheel so as to be rotatable and the function of guiding the lens frame so as to be movable in the optical axis direction.

In the above structure, the spring is formed to urge the lens frame in order to maintain the engagement between the cam and the follower part in the optical axis direction can be adopted a configuration.
According to this configuration, in the configuration in which the spring is provided on one side of the plane containing the central axis of the optical axis supporting shaft, since the spring exerts a biasing force for maintaining the engagement between the cam and follower unit, Even in the case where the rotational movement is converted into the straight movement by the cam action, the lens frame always receives a moment to tilt the central axis of the guide hole toward one side of the plane, and the guide hole The contact state between the inner peripheral surface of the lens and the outer peripheral surface of the support shaft can be stabilized, and the optical axis of the lens frame can be prevented from wobbling and the captured image from changing.

In the above configuration, the spring may be configured to be stretched between the protruding arm portion of the lens frame and the fixed frame.
According to this structure, the urging | biasing force of a spring acts on a protrusion arm part directly, and a follower part and a cam can be engaged reliably.

In the above configuration, the cam may be an end face cam that is integrally and annularly formed at one end of the worm wheel in the central axis direction.
According to this configuration, the number of parts can be reduced, and the assembly of the apparatus becomes easy.

In the above-described configuration, the conversion mechanism includes a lead screw that rotates integrally coaxially with the worm wheel, and a nut that is screwed to the lead screw and provided so as to move integrally with the lens frame. Can be adopted.
According to this configuration, the rotation of the motor is decelerated by the worm gear and the worm wheel, is further decelerated by the lead screw and the nut, is converted into a linear motion, and is transmitted to the lens frame. As a result, a large reduction ratio can be ensured and the conversion mechanism can be miniaturized.

In the above configuration, the lens frame, that have a protruding arm portion mounting portion及beauty draft bore the nut is mounted to protrude outwardly in the radial direction are formed, it can adopt a configuration.
According to this configuration, by supporting shaft of the fixed frame in the guide hole of this is inserted fitting to form a guide hole in the projecting arm of the lens frame, made accurately guide the lens frame in the optical axis direction It is possible to prevent the optical axis of the lens frame from wobbling.

In the configuration described above, a configuration in which a cover having an opening for allowing subject light to pass through is coupled to the fixed frame and the cover receives the other end of the spring can be employed.
According to this configuration, the assembly of the apparatus becomes easy and the number of parts can be reduced.

  According to the lens driving device of the present invention, it can be mounted in a narrow mounting space such as a portable information terminal while realizing an automatic focusing function or an automatic zooming function. Also, stable imaging performance can be obtained by preventing the optical axis of the lens frame from wobbling.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings.
1 to 7 show an embodiment of a lens driving device according to the present invention. FIG. 1 is a perspective view showing the appearance of the device, FIG. 2 is a perspective view showing the internal structure of the device, and FIG. FIG. 4 is an exploded perspective view of the device, FIG. 5 is a perspective view showing the appearance of the lens frame and the drive mechanism, FIG. 6 is a perspective view showing the appearance of the lens frame, and FIG. 7 is a cross-sectional view of the apparatus in which the lens frame is in the extended position.

As shown in FIGS. 1 to 5, this apparatus holds a lens frame 10 that holds a lens G and a filter glass 16 inside, a CCD 100 as an imaging device, and holds the lens frame 10 in the direction of the optical axis L (hereinafter referred to as “optical axis L”). A fixed frame 20 that is movably supported in the optical axis direction), a motor 30, a worm gear 40, and a worm wheel that are part of a drive mechanism that is held by the fixed frame 20 and moves the lens frame 10 in the optical axis direction. 41, a cover 50 having an opening 51 through which subject light passes and fixed to the fixed frame 20, a spring 60 for urging the lens frame 10 in the optical axis direction, and position detection for detecting the position of the lens frame 10 in the optical axis direction And so on.
The camera unit is formed by holding the CCD 100 as the imaging device on the fixed frame 20.

  In this apparatus, subject light enters the lens G from the front in the optical axis direction through the opening 51 and reaches the CCD 100. Then, when the lens G is moved in the optical axis direction, the subject is focused on the imaging surface of the CCD 100.

The lens frame 10 is formed of a resin so as to define a cylindrical portion that holds the lens G, and as shown in FIGS. 2 to 6, a protruding arm portion 11 that protrudes outward in the radial direction. , A detected protruding piece 14 detected by the position detector 70, and a restricting protruding piece 15 inserted into a restricting groove 21 described later of the fixed frame 20.
The protruding arm portion 11 is formed to extend in the optical axis direction at the distal end portion thereof, and is a guide hole 12 into which a support shaft 22 described later is fitted and inserted, and is formed to protrude to the rear side in the optical axis direction and is described later. 42, a follower portion 11 a that engages with 42, a latching protruding piece 13 on which one end of the spring 60 is latched, and the like. When the support shaft 22 is slidably fitted and inserted into the guide hole 12, the lens frame 10 is supported by the fixed frame 20 so as to be movable in the optical axis direction.
The position of the detected protruding piece 14 in the optical axis direction is optically detected by the position detector 70. Thereby, the position of the lens frame 10 in the optical axis direction can be detected.
The restricting protruding piece 15 is inserted into a later-described restricting groove 21 of the fixed frame 20 to restrict the lens frame 10 from turning about a support shaft 22 described later.

The fixed frame 20 is formed of a resin and has a rectangular outer shape as shown in FIGS. 1 to 4 and accommodates a restriction groove 21 through which the restriction projection piece 15 is inserted and the lens frame 10 inside thereof. The frame housing section 24, the mounting section 23 to which the CCD 100 is mounted, the motor 30, the worm gear 40 and the worm wheel 41 are provided inside the mechanism housing section 25, the mounting section 26 to which the position detector 70 is attached, and the like. The fixed frame 20 is integrally formed with a support shaft 22 extending in the optical axis direction at a position separated from the optical axis L by a predetermined distance on the bottom surface thereof.
The support shaft 22 is formed so as to gradually decrease in diameter from the base toward the tip, and a large diameter portion on the base side is slidably fitted and inserted into the shaft hole 41a of the worm wheel 41. Is inserted into the guide hole 12 so as to be slidable. Thus, the lens frame 10 is guided by the support shaft 22 so as to be movable in the optical axis direction.

As shown in FIGS. 2 to 5, the motor 30 is fixed to the fixed frame 20 by a stay 32 so that the rotating shaft 31 extends in a direction substantially perpendicular to the optical axis direction.
The worm gear 40 is made of resin and is fixed to the rotating shaft 31.
The worm wheel 41 is made of resin, and a large-diameter portion on the base side of the support shaft 22 is slidably fitted in the shaft hole 41a. Thereby, the worm wheel 41 is supported by the fixed frame 20 so as to be rotatable about the center axis J1 of the support shaft 22 as an axis separated from the optical axis L by a predetermined distance, and meshes with the worm gear 40. The rotation of the rotating shaft 31 of the motor 30 is decelerated at a predetermined reduction ratio via the worm gear 40 and transmitted to the worm wheel 41.
The cam 42 is provided coaxially with the worm wheel 41 and includes an end face cam formed integrally and annularly at one end in the central axis direction of the worm wheel 41. The annular cam surface 42a is connected to the follower portion 11a. It abuts (engages) and exerts a cam action in the optical axis direction. That is, the cam 42 rotates together with the worm wheel 41, converts the rotation of the worm wheel 41 into a linear movement in the optical axis direction around the central axis J1, and transmits it to the lens frame 10 (the follower portion 11a). Function.

  The cover 50 is formed of resin, and has an outer shape substantially matching the fixed frame 20 and an opening 51 through which subject light passes, and is fixed to the fixed frame 20 by a bolt BT, as shown in FIGS. Is done.

  The spring 60 is formed in a coil shape, and as shown in FIGS. 2, 4, and 5, one end of the spring 60 is hooked on the hooking protruding piece 13 of the protruding arm 11 and the other end. Is latched by a latching protrusion (not shown) formed on the bottom surface of the fixed frame 20 to urge the lens frame 10 toward the fixed frame 20 in the optical axis direction. Thereby, engagement with the cam 42 and the follower part 11a is maintained. The spring 60 is provided on one side (motor 30 side) of a plane including the central axis J1 of the support shaft 22 and the optical axis L. As a result, a moment to incline the central axis of the guide hole 12 toward one side of the plane always acts on the lens frame 10, so that contact between the inner peripheral surface of the guide hole 12 and the outer peripheral surface of the support shaft 22 occurs. The state can be stabilized. That is, even if there is a slight clearance between the guide hole 12 and the support shaft 22, the contact state between the guide hole 12 and the support shaft 22 is maintained substantially constant by the above moment. Therefore, it is possible to prevent the captured image from changing due to the optical axis L of the lens frame 10 wobbling.

  The position detector 70 is, for example, a transmissive or reflective optical sensor including a light emitting element and a light receiving element, and optically detects the detected protruding piece 14 of the lens frame 10, whereby the optical axis of the lens frame 10 is detected. Detect the position of the direction.

Next, the operation of the lens driving device will be described with reference to FIGS.
As shown in FIG. 3, the lens frame 10 of the lens driving device is in a state in which the follower portion 11a is brought into contact with the lowest position of the cam surface 42a and retracted rearward in the optical axis direction. When the rotating shaft 31 of the motor 30 is rotated in one direction from this state, the cam 42 is rotated in one direction, and the lens frame 10 moves forward in the optical axis direction by the cam action of the cam surface 42a. Then, as shown in FIG. 7, when the follower portion 11a comes into contact with the highest position of the cam surface 42a, the lens frame 10 is in the state of being extended most forward in the optical axis direction. In addition, what is necessary is just to rotate the rotating shaft 31 of the motor 30 in the reverse direction in order to return the lens frame 10 to a retracted position. Further, by searching for a focus position based on the captured image between the retraction position shown in FIG. 3 and the retraction position shown in FIG.

  As described above, according to the present embodiment, since the worm gear 40 and the worm wheel 41 are employed as the speed reducer in the drive mechanism that moves the lens frame 10 in the optical axis direction, the drive mechanism can be reduced in size. Further, since the cam 42 for converting the rotation of the worm wheel 41 into a linear motion in the optical axis direction and transmitting it to the lens frame 10 is provided on the same axis J1 as the worm wheel 41, the drive mechanism can be integrated and the apparatus can be made compact. Can be realized.

  8 to 13 show another embodiment of the lens driving device according to the present invention. FIG. 8 is a front view of the device, FIG. 9 is a sectional view of the device with the lens frame in the retracted position, and FIG. 11 is an exploded perspective view of the apparatus, FIG. 11 is a perspective view showing the external appearance of the lens frame, drive mechanism, and spring, FIG. 12 is an exploded perspective view of the lens frame, drive mechanism, and spring, and FIG. 13 is the lens frame in the extended position. It is sectional drawing of an apparatus.

  As shown in FIGS. 8 to 12, this apparatus is held by a lens frame 110 that holds the lens G inside, a fixed frame 120 that supports the lens frame 110 movably in the optical axis direction, and a fixed frame 120. A motor 130, a worm gear 140, and a worm wheel 141 that constitute a part of a drive mechanism that moves the lens frame 110 in the optical axis direction, a lead screw 142 and a nut 143 that constitute a part of the drive mechanism and a conversion mechanism, and a subject A cover 150 having an opening 151 through which light passes and connected to the fixed frame 120, a spring 160 for urging the lens frame 110 in the direction of the optical axis L, and a position for detecting the position of the lens frame 110 in the direction of the optical axis L A detector 170 and the like are provided.

  In this apparatus, subject light enters the lens G through the opening 151 from the front direction of the optical axis L, and reaches an image sensor (not shown) disposed behind the apparatus. Then, when the lens G is moved in the optical axis direction, the subject is focused on an imaging plane of an image sensor (not shown).

The lens frame 110 is formed of a resin so as to define a cylindrical portion that holds the lens G, and as shown in FIGS. 9 to 12, the protruding arm portion 111 is formed to protrude outward in the radial direction. , A restricting protruding piece 117 inserted into a restricting groove 121 described later of the fixed frame 120, a detected protruding piece 118 detected by the position detector 170, and the like.
The protruding arm portion 111 includes a guide hole 112 that is formed to extend in the optical axis direction and into which a support shaft 122 (described later) of the fixed frame 120 is slidably fitted and inserted, an attachment portion 113 to which a nut 143 is attached, and the like. .
By fitting and inserting a support shaft 122 (described later) of the fixed frame 120 into the guide hole 112, the lens frame 110 is supported by the fixed frame 120 so as to be movable in the optical axis direction.
The attachment portion 113 is formed integrally with the protruding arm portion 111, and the insertion hole 114 through which the lead screw 142 is inserted, the spring receiving portion that is formed on the front side in the optical axis direction and supports one end portion of the spring 160. 115, an abutting surface 116 formed on the rear side in the optical axis direction, on which the nut 143 abuts, a mounting hole 119 into which a protruding piece 143a (described later) of the nut 143 is fitted and inserted.
The restricting protruding piece 117 plays a role of restricting the lens frame 110 from turning around a support shaft 122 described later by being inserted into a restricting groove 121 described later of the fixed frame 120.
The position of the detected protruding piece 118 in the optical axis direction is optically detected by the position detector 170. Thereby, the position of the lens frame 110 in the optical axis direction can be detected.

The fixed frame 120 is made of resin and has a rectangular outer shape as shown in FIGS. 9 and 10, and a restriction groove 121 that extends in the optical axis direction and through which the restriction protruding piece 117 is inserted, and a lens frame. A cylindrical frame housing portion 123 for housing 110 inside, a mechanism housing portion 124 for housing a drive mechanism excluding the motor 30, a motor housing portion 125 for housing the motor 30, a mounting portion 126 for attaching the position detector 170, and the like. I have. Further, the fixed frame 120 is integrally formed with a support shaft 122 extending in the optical axis direction at a position separated from the optical axis L by a predetermined distance on the bottom surface thereof, and one of the lead screws 142 is provided. An annular support protrusion 128 that defines a support hole 128a that rotatably supports the shaft end is formed.
The support shaft 122 is formed such that the tip side thereof is smaller in diameter than the base side, and both the large diameter portion on the base side and the small diameter portion on the tip side are slidably fitted into the guide hole 112 of the lens frame 110. To do. Thereby, the lens frame 110 is guided to be movable in the optical axis direction.

The motor 130 is fixed to the fixed frame 120 so that the rotating shaft 131 is substantially orthogonal to the optical axis direction.
The worm gear 140 is formed in an annular shape with resin and is fixed to the rotating shaft 131.
The worm wheel 141 is formed in an annular shape from resin, and a lead screw 142 is fitted and inserted into the shaft hole 141 a and fixed to the lead screw 142. Thus, the worm wheel 141 is supported by the fixed frame 120 so as to be rotatable about the central axis J2 of the lead screw 142 as an axis separated from the optical axis L by a predetermined distance.

The lead screw 142 is formed of resin, and, as shown in FIGS. 9 to 12, one shaft end is rotatably supported by the shaft hole 128 a of the fixed frame 120 and the other shaft end is the cover 150. Is inserted into a shaft hole 153, which will be described later, in a slidable manner.
The nut 143 is formed in an annular shape from resin, and is provided so as to be screwed into the lead screw 142 and move integrally with the lens frame 110 as shown in FIGS. 9 to 12. The nut 143 is formed with a protruding piece 143 a protruding from the outer peripheral surface thereof through the mounting hole 119 of the mounting portion 113. By inserting the protruding piece 143a into the mounting hole 119, the nut 143 is fixed to the mounting portion 113, and rotation and movement in the optical axis direction are restricted. As a result, when the lead screw 142 rotates, the nut 143 moves in the direction of the central axis J2. That is, the lead screw 142 and the nut 143 function as a conversion mechanism that converts the rotation of the worm wheel 141 into a linear movement in the optical axis direction and transmits it to the lens frame 110 (the contact surface 116 thereof) around the central axis J2. . Further, the lead screw 142 and the nut 143 further reduce the rotation of the worm wheel 141 at a predetermined reduction ratio and transmit it to the lens frame 110. For this reason, even if the rotational torque of the motor 130 is small, a large linear force can be exerted on the lens frame 110 in the optical axis direction.

  The cover 150 is made of resin and has an outer shape that substantially matches the fixed frame 120 as shown in FIGS. 8 to 10, and snaps to the opening 151 through which subject light passes and the latching protrusion piece 127 of the fixed frame 120. A hook groove piece 152 for connecting the cover 150 to the fixed frame 120 after being fitted, a shaft hole 153 into which the shaft end of the lead screw 142 is slidably fitted and inserted, a spring receiving portion 154 for supporting the spring 160, and the like. I have.

The spring 160 is a compression spring formed in a coil shape. As shown in FIGS. 9 to 11, the spring 160 is arranged around the lead screw 142 and one end thereof is supported by the spring receiving portion 115 of the attachment portion 113. In addition, the other end portion is supported by the spring receiving portion 154 of the cover 150 and urges the lens frame 110 toward the fixed frame 120 side. Thereby, the play between the nut 143 and the lead screw 142 is reliably removed.
The spring 160 is provided on one side (motor 130 side) of a plane including the central axis J3 of the support shaft 122 and the optical axis L. As a result, a moment to incline the central axis of the guide hole 112 toward one side of the plane always acts on the lens frame 110, so that the inner peripheral surface of the guide hole 112 and the outer peripheral surface of the support shaft 122 are in contact with each other. Can be stabilized. That is, even if a slight clearance exists between the guide hole 112 and the support shaft 122, the contact state between the inner peripheral surface of the guide hole 112 and the outer peripheral surface of the support shaft 122 is maintained substantially constant by the moment. Is done. Therefore, it is possible to prevent the captured image from changing due to the wobbling of the optical axis L of the lens frame 110.

  The position detector 170 is, for example, a transmissive or reflective optical sensor that includes a light emitting element and a light receiving element, and optically detects the detected protruding piece 118 of the lens frame 110, whereby the optical axis of the lens frame 110 is detected. Detect the position of the direction.

Next, the operation of the lens driving device will be described with reference to FIGS.
As shown in FIG. 9, in the lens frame 110, the nut 143 screwed on the rear side in the optical axis direction of the lead screw 142 abuts on the abutting surface 116 and is retracted rearward in the optical axis direction. is there. When the rotating shaft 131 of the motor 130 is rotated in one direction from this state, the lead screw 142 rotates, and the lens frame 110 is pushed forward by the nut 143 in the optical axis direction and moves. And the lens frame 110 will be in the state extended to the front of the optical axis direction, as shown in FIG. In order to return the lens frame 110 to the retracted position, the rotation shaft 131 of the motor 130 may be rotated in the opposite direction. Further, a focusing operation is performed by searching for a focusing position based on the captured image between the feeding position shown in FIG. 9 and the feeding position shown in FIG.

  As described above, according to the present embodiment, the worm gear 140, the worm wheel 141, the lead screw 142, and the nut 143 are employed as the reduction mechanism of the drive mechanism that moves the lens frame 110 in the optical axis direction. While realizing a reduction in size, a larger reduction ratio can be ensured, and a load caused by friction acting between the worm gear 140 and the worm wheel 141 can be reduced. Further, since the lead screw 142 and the nut 143 as the conversion mechanism are arranged coaxially with the worm wheel 141, the drive mechanism can be integrated and the apparatus can be downsized.

  In the above embodiment, the case where the support shafts 22 and 122 are formed integrally with the fixed frames 20 and 120 has been described. However, the present invention is not limited to this, and the support shafts 22 and 122 are the fixed frames 20 and 120. It may be formed separately and fixed to the fixed frames 20 and 120.

  In the above embodiment, the case where the cam 42 is formed integrally with the worm wheel 41 has been described. However, the present invention is not limited to this, and the cam 42 may be formed separately and coupled to the worm wheel 41. .

  In the above-described embodiment, the case where the springs 60 and 160 are disposed on one side (the motors 30 and 130 side) of the plane including the central axes J1 and J3 of the support shafts 22 and 122 and the optical axis L has been described. It is not limited to this, It is also possible to arrange | position on the opposite side. Further, by inverting the biasing direction of the spring, it is possible to provide a spring for biasing between the lens frame 10 and the cover 50 instead of between the lens frame 10 and the fixed frame 20. It is possible to provide a biasing spring between the lens frame 110 and the fixed frame 120 instead of between the frame 110 and the cover 150.

In the above embodiment, the case where the nut 143 and the lens frame 110 are separately formed has been described. However, the present invention is not limited to this, and the nut 143 can be integrally formed with the protruding arm portion 111. .
In the above-described embodiment, the nut 143 is attached to the lens frame 110. However, the present invention is not limited to this, and the nut 143 is brought into contact with the lens frame 110 so that the rotation of the nut 143 is restricted. A configuration in which the contact state between the nut 143 and the lens frame 110 is maintained by the urging force of 160 is also possible.

  As described above, the lens driving device of the present invention is applied as a lens driving device for a digital camera unit mounted on a portable information terminal or the like that is required to be reduced in size and weight, such as a mobile phone and a portable personal computer. Needless to say, the present invention is useful in other lens optical systems as long as the lens needs to be driven.

It is a perspective view which shows the external appearance of the lens drive device which concerns on one Embodiment of this invention. It is a perspective view of an apparatus in the state where a cover was removed. It is sectional drawing of the apparatus in the state which the lens frame retracted. It is a disassembled perspective view of an apparatus. (A) is the perspective view seen from one direction of a lens frame and a drive mechanism, (b) is the perspective view seen from the other direction. (A) is a perspective view of the lens frame seen from diagonally upward, (b) is a perspective view of the lens frame seen from diagonally downward. It is sectional drawing of the apparatus in the state by which the lens frame was extended. It is a front view of the lens drive device concerning other embodiments of the present invention. It is sectional drawing of the AA direction in FIG. It is a disassembled perspective view of an apparatus. It is a perspective view of a lens frame, a drive mechanism, and a spring. It is a disassembled perspective view of a lens frame, a drive mechanism, and a spring. It is sectional drawing of the AA direction of FIG. 8 in the state which the lens frame extended.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Lens frame 11 ... Projection arm part 11a ... Follower part 12 ... Guide hole 13 ... Locking protrusion piece 14 ... Detecting protrusion piece 15 ... Restriction protrusion piece 16 ... Filter glass 20 ... Fixed frame 21 ... Restriction groove 22 ... Support Shaft 23 ... Mounting portion 24 ... Frame housing portion 25 ... Mechanical housing portion 26 ... Mounting portion 30 ... Motor (drive mechanism)
31 ... Rotating shaft 32 ... Stay 40 ... Worm gear (drive mechanism)
41. Worm wheel (drive mechanism)
42. Cam (conversion mechanism, drive mechanism)
42a ... cam surface 50 ... cover 51 ... opening 60 ... spring 70 ... position detector 100 ... CCD
J1 ... Center axis of the support shaft (axis)
DESCRIPTION OF SYMBOLS 110 ... Lens frame 111 ... Projection arm part 112 ... Guide hole 113 ... Attachment part 114 ... Insertion hole 115 ... Spring receiving part 116 ... Abutting surface 117 ... Protrusion piece 118 for regulation ... Projection piece 119 to detect ... Frame 121 ... Restriction groove 122 ... Support shaft 123 ... Frame housing portion 124 ... Mechanism housing portion 125 ... Motor housing portion 126 ... Mounting portion 127 ... Suspension protrusion 128 ... Supporting projection 130 ... Motor (drive mechanism)
131: Rotating shaft 140: Worm gear (drive mechanism)
141. Worm wheel (drive mechanism)
142 ... Lead screw (conversion mechanism, drive mechanism)
143 ... nut (conversion mechanism, drive mechanism)
143a ... projecting piece 150 ... cover 151 ... opening 152 ... retaining groove piece 153 ... support hole 154 ... spring receiving portion 160 ... spring 170 ... position detector J2 ... central axis (axis) of lead screw
J3 ... Center axis G of support shaft ... Lens L ... Optical axis BT ... Bolt

Claims (9)

A lens frame having a guide hole that holds the lens and extends in the optical axis direction ; and a fixed frame having a support shaft that is fitted and inserted into the guide hole to support the lens frame movably in the optical axis direction; A spring that urges the lens frame in the optical axis direction, and a drive mechanism that is held by the fixed frame and moves the lens frame in the optical axis direction,
The drive mechanism is rotatably supported by the fixed frame about a motor fixed to the fixed frame, a worm gear fixed to the rotation shaft of the motor, and an axis separated from the optical axis by a predetermined distance. A worm wheel that meshes with the worm gear, and a conversion mechanism that is provided coaxially with the worm wheel and that converts the rotation of the worm wheel into a linear motion in the optical axis direction and transmits it to the lens frame ,
The spring is provided on one side of a plane including the optical axis and the central axis of the support shaft.
A lens driving device. The conversion mechanism includes a cam that engages with a follower portion formed in the lens frame and rotates with the worm wheel to exert a cam action in the optical axis direction.
The lens driving device according to claim 1. The lens frame has a projecting arm portion to which the follower part and the guide hole and protrudes outwardly in the radial direction are formed,
Said support shaft, said worm wheel you rotatably supported with movably guide the lens frame in the optical axis direction,
The lens driving device according to claim 2. The spring is formed to urge the lens frame in the optical axis direction so as to maintain the engagement between the cam and the follower portion .
The lens driving device according to claim 3 . The spring is stretched between the protruding arm portion of the lens frame and the fixed frame.
The lens driving device according to claim 4. The cam is an end face cam formed integrally and annularly at one end in the central axis direction of the worm wheel.
The lens driving device according to claim 2, wherein the lens driving device is a lens driving device. The conversion mechanism includes a lead screw that rotates integrally coaxially with the worm wheel, and a nut that is screwed to the lead screw and that moves integrally with the lens frame.
The lens driving device according to claim 1. The lens frame is closed a protruding arm portion mounting portion and the guide hole wherein the nut is mounted to protrude outwardly in the radial direction are formed,
The lens driving device according to claim 7. A cover having an opening that allows subject light to pass through is coupled to the fixed frame.
The cover receives the other end of the spring;
The lens driving device according to claim 1 , wherein the lens driving device is a lens driving device.

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