JP4652007B2 - Lens drive device - Google Patents

Description

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

In order for the camera to have a macro switching function for switching between a close-up shooting position (macro shooting position) and a normal shooting position, a zoom function, or a focusing function, a lens driving device that moves the lens in the optical axis direction is required. Become. As a conventional lens driving device, an actuator using a shape memory alloy for an actuator for driving a lens is known (see, for example, Patent Document 1 and Patent Document 2).
Japanese Utility Model Publication No. 1-128209 JP-A-9-127398

By the way, in order to incorporate the lens driving device into a portable information terminal such as a cellular phone or a portable personal computer, it is necessary to reduce the size and to move the lens smoothly and quickly.
However, in the conventional lens driving device using the shape memory alloy, the shape memory alloy is accommodated in the lens barrel, so it takes time until it is naturally cooled and restored to a predetermined shape after being heated, It was difficult to move the lens smoothly and quickly. Further, in a conventional lens driving device using a shape memory alloy, since a guide mechanism such as a guide rod is used to smoothly drive the lens in the optical axis direction, it is difficult to reduce the size of the device.

  The present invention has been made in view of the above circumstances, and the object of the present invention is to enable the lens to be moved smoothly and quickly and to be miniaturized so that it can be incorporated into a portable information terminal. The object is to provide a lens driving device.

A lens driving device according to the present invention includes a lens frame that holds a lens, a fixed frame that has a cylindrical support portion that supports the lens frame so as to be movable only in the optical axis direction, a coil spring that can expand and contract in the optical axis direction, The coil spring is formed of a shape memory alloy so as to be concentrically exposed and arranged outside the cylindrical support portion, and to expand and contract in the optical axis direction due to a temperature change caused by energization / non-energization. are seen including a shape memory alloy spring, the coil spring comprises a front coil spring and a rear coil spring disposed in contact with so as to urge the lens frame from the front and rear sides of the optical axis direction, the front coil spring and rear spring At least one of them is a shape memory alloy, and the lens frame is connected to the arm portion and radially outside the outer peripheral surface of the lens frame, and disposed on the outside of the cylindrical support portion. Has an annular spring receiving portion for receiving one end of the side spring, a cylindrical support portion has a guide hole formed extends in the optical axis direction so as to insert the arm portion, and characterized in that.
According to this configuration, the shape memory alloy spring is exposed to the outside of the cylindrical support portion and is efficiently cooled when the energization is stopped from a state where the shape memory alloy spring is heated and expanded or contracted by the energization. Quickly contracts or stretches. Therefore, the lens frame can be quickly moved in the optical axis direction. Further, since the lens is separated from the shape memory alloy spring by the cylindrical support portion, the heat generated by the shape memory alloy spring can be prevented from affecting the lens and its optical path. Furthermore, since the shape memory alloy springs are arranged concentrically outside the cylindrical support portion, a force acts on the lens frame substantially evenly around the optical axis, and the lens frame light is moved when moving in the optical axis direction. The lens frame can be smoothly moved without the shaft being shaken.
In particular, when one of the front coil spring and the rear coil spring is heated and expanded by energization, the one coil spring moves the lens frame from one shooting position to another shooting position while resisting the biasing force of the other coil spring. When energization of one coil spring is stopped, one coil spring is naturally cooled and contracts. At this time, since the lens frame is always urged by the other coil spring, it quickly moves again to one photographing position.
Further, it is possible to guide the lens frame so as to be movable only in the direction of the optical axis, while realizing miniaturization of the apparatus and easy assembly.

The lens driving device according to the present invention includes a lens frame that holds a lens, a fixed frame that has a cylindrical support portion that supports the lens frame so as to be movable only in the optical axis direction, and a coil spring that can expand and contract in the optical axis direction. And the coil spring is arranged concentrically so as to be exposed to the outside of the cylindrical support portion, and expands and contracts in the optical axis direction due to a temperature change caused by energization / non-energization to generate a driving force. The shape memory alloy spring is formed by: one end of the shape memory alloy spring is hooked on one of the fixed frame and the lens frame so as to be relatively rotatable around the optical axis, and the other end is fixed on the fixed frame and the lens. The lens frame is hooked to the other side of the frame, and the lens frame protrudes in a radial direction from the outer peripheral surface thereof, an annular support portion connected to the arm portion and disposed outside the cylindrical support portion, and an annular support portion Is supported so as to be rotatable around the optical axis. Has a spring receiving ring to which one end of the shape memory alloy spring is hooked, a cylindrical support portion has a guide hole formed extends in the optical axis direction so as to insert the arm portion, characterized in that It is said.
According to this configuration, the shape memory alloy spring is exposed to the outside of the cylindrical support portion and is efficiently cooled when the energization is stopped from a state where the shape memory alloy spring is heated and expanded or contracted by the energization. Quickly contracts or stretches. Therefore, the lens frame can be quickly moved in the optical axis direction. In addition, since the lens is separated from the shape memory alloy spring by the cylindrical support portion, it is possible to prevent the heat generated by the shape memory alloy spring from affecting the lens and its optical path. Further, since the shape memory alloy spring is concentrically disposed outside the cylindrical support portion, a force acts on the lens frame substantially evenly around the optical axis, and the light of the lens frame is moved when moving in the optical axis direction. The lens frame can be smoothly moved without the shaft being shaken.
In addition, the structure of the apparatus is simplified and the rotation component generated when the shape memory alloy spring is expanded and contracted can be prevented from being transmitted to the lens frame, so that the lens frame can be moved smoothly. Further, the lens frame can be guided so as to be movable only in the optical axis direction, and the rotational component generated in the shape memory alloy spring can be smoothly absorbed by the spring receiving ring.

  According to the lens driving device of the present invention, the lens can be driven smoothly and quickly using the shape memory alloy spring, and the lens can be miniaturized so that it can be incorporated into a portable information terminal. Installation work becomes very easy.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the accompanying drawings.
1 to 5 show an embodiment of a lens driving apparatus according to the present invention. FIG. 1 is a side view of the apparatus in which the lens frame is in a normal photographing position, and FIG. 2 is a lens frame in the normal photographing position. FIG. 3 is an exploded perspective view of the apparatus, FIG. 4 is a side view of the apparatus in which the lens frame is in the close-up position, and FIG. 5 is a light of the apparatus in which the lens frame is in the close-up position. It is sectional drawing of an axial direction.

  As shown in FIGS. 1 to 3, this apparatus holds a lens frame 10 for holding a lens G, a CCD 200 as an imaging device, and the lens frame 10 in the direction of the optical axis L (hereinafter referred to as the optical axis direction). A fixed frame 20 that is movably supported, and is disposed outside a cylindrical support portion 22 (to be described later) of the fixed frame 20 so as to be concentrically arranged with the optical axis L as the center, and urges the lens frame 10 in the optical axis direction. A front coil spring 30 and a rear coil spring 40 as a shape memory alloy spring, and a spring receiving member 50 fixed to a cylindrical support portion 22 (to be described later) of the fixed frame 20 are provided.

  In this apparatus, the subject light enters the lens G from the optical axis direction and forms an image on the imaging surface of the CCD 200. The camera unit is formed by holding the CCD 200 on the fixed frame 20.

The lens frame 10 is formed in a substantially cylindrical shape with resin, and as shown in FIGS. 1 to 3, the lens frame 10 is held inside and slidably fitted to an inner peripheral surface 22 a described later of the fixed frame 20. A cylindrical outer peripheral surface 11 centering on the optical axis L to be combined, an annular spring receiving portion 12 that is disposed outside the outer peripheral surface 11 and receives one end of the front coil spring 30 and the rear coil spring 40, and from the outer peripheral surface 11 in the radial direction Are provided with an arm portion 13 and the like that are connected to the spring receiving portion 12.
The spring receiving portion 12 receives one end of the front coil spring 30 by an annular receiving surface 12a formed in the front in the optical axis direction, and the rear coil spring 40 on the annular receiving surface 12b formed in the rear in the optical axis direction. Receive one end.
The arm portion 13 protrudes in the radial direction from the outer peripheral surface 11, and a plurality (three) of the arm portion 13 is formed at equal intervals in the circumferential direction of the spring receiving portion 12, and is inserted into a guide hole 23 described later of the fixed frame 20.

The fixed frame 20 is formed of resin to define the outer contour of the apparatus, and as shown in FIGS. 1 to 3, a base 21 as a holding part for holding the CCD 200 and a cylindrical shape from the base 21 in the optical axis direction. And a cylindrical support portion 22 and the like that extend.
The base portion 21 has a rectangular outer shape, and includes a front surface 21a that is positioned in front of the optical axis direction and receives the rear coil spring 40, a holding portion 21b that holds the CCD 200, and the like.
The cylindrical support portion 22 is formed to extend from the front surface 21a of the base portion 21 in the optical axis direction, and has a cylindrical shape with an optical axis L around which the outer peripheral surface 11 of the lens frame 10 is slidably fitted. Light is emitted from the inner peripheral surface 22a, the annular front end surface 22b to which the spring receiving member 50 is fixed, the plurality of protrusions 22c formed on the front end surface 22b and fitted in the fitting holes 50a described later of the spring receiving member 50, and the front end surface 22b. A plurality of (three) guide holes 23 and the like are provided that extend rearward in the axial direction and are equally spaced in the circumferential direction.
The cylindrical support portion 22 slidably fits the outer peripheral surface 11 of the lens frame 10 to the inner peripheral surface 22a thereof, thereby supporting the lens frame 10 so as to be movable in the optical axis direction. When the arm portion 13 is inserted through the guide hole 23, the rotation of the lens frame 10 around the optical axis L is restricted and guided so as to be movable in the optical axis direction. Thereby, the lens frame 10 is supported by the cylindrical support part 22 so as to be movable only in the optical axis direction.

  The front coil spring 30 is formed by coiling a metal wire such as steel into a coil shape, and is exposed to the outside of the cylindrical support portion 22 with the optical axis L as the center, as shown in FIGS. The lens frame 10 is arranged concentrically, and one end thereof is in contact with the spring receiving portion 12 (the annular receiving surface 12a) of the lens frame 10 and the other end is in contact with the spring receiving member 50. It is urging from the front of the direction toward the rear.

The rear coil spring 40 is a shape memory alloy spring obtained by forming a shape memory alloy wire rod as a unidirectional element into a coil shape, and is exposed to the outside of the cylindrical support portion 22 as shown in FIGS. Are arranged concentrically with the optical axis L as the center, one end abuts against the front surface 21a of the base portion 21, and the other end contacts the spring receiving portion 12 (the annular receiving surface 12b) of the lens frame 10. By contacting, the lens frame 10 is urged forward from the rear side in the optical axis direction.
The shape memory alloy is a metal having a property that the deformation strain given in advance becomes zero in a specific temperature region and recovers to the original shape, and is, for example, a Ni—Ti alloy.
Both ends of the rear coil spring 40 are electrically connected to the drive circuit 250 and the surface thereof is covered with an electrically insulating material (not shown). When the rear coil spring 40 is energized by the drive circuit 250, the rear coil spring 40 is heated to a specific temperature region, and the pitch extends by a predetermined length in the optical axis direction. Further, when the energization is stopped, the rear coil spring 40 is naturally cooled and contracted by a predetermined length in the optical axis direction by the urging force of the coil spring 30 to recover the shape before being heated. That is, the rear coil spring 40 expands and contracts in the optical axis direction due to a temperature change caused by energization / non-energization, and drives the lens frame 10 in the optical axis direction.

  The spring receiving member 50 is formed in an annular shape with resin, and as shown in FIGS. 1 to 3, the spring receiving member 50 includes a plurality of fitting holes 50a into which the protrusions 22c of the cylindrical support portion 22 are fitted. Is fixed to the front end surface 22b of the cylindrical support portion 22 with an adhesive or the like. The spring receiving member 50 is fixed to the front end surface 22 b of the cylindrical support portion 22, thereby preventing the lens frame 10 from falling out of the guide hole 23 and receiving one end of the front coil spring 30.

  The assembly procedure of the lens driving device described above is as follows. First, the rear coil spring 40 is fitted to the outside of the cylindrical support portion 22 from the front end side, then the lens frame 10 holding the lens G, the arm portion 13 is guided to the guide hole 23. Is fitted into the inner peripheral surface 22a of the cylindrical support portion 22 from the front end side. Next, after the front coil spring 30 is fitted to the outside of the cylindrical support portion 22 from the front end side, the spring receiving member 50 is fixed to the front end surface 22 b of the cylindrical support portion 22. Thereby, the assembly of the lens driving device is completed. Thus, since it can assemble | attach all from the front end side of the cylindrical support part 22, an assembly | attachment operation | work becomes very easy.

The operation of the lens driving device will be described with reference to FIGS. 1, 2, 4 and 5. As shown in FIGS. 1 and 2, the lens frame 10 of the lens driving device is in the normal photographing position. In the state, the lens frame 10 is retracted rearward in the optical axis direction. In order to move the lens frame 10 from this position to the close-up shooting position, the drive coil 250 energizes the rear coil spring 40. The drive circuit 250 is activated when the operator operates an operation button or the like when the device is mounted on a portable information terminal.
When energized, the rear coil spring 40 is heated by its electrical resistance and extends in the optical axis direction, and moves the lens frame 10 forward in the optical axis direction against the urging force of the front coil spring 30. Accordingly, as shown in FIGS. 4 and 5, the lens frame 10 is drawn forward of the cylindrical support portion 22 and reaches the close-up photographing position.

  In order to move the lens frame 10 from the close-up shooting position to the normal shooting position, the energization of the rear coil spring 40 by the drive circuit 250 is stopped. When the energization is stopped, the temperature of the rear coil spring 40 decreases due to natural cooling and contracts in the optical axis direction due to the urging force of the coil spring 30. At this time, since the rear coil spring 40 is exposed to the outside of the apparatus, it is efficiently cooled and contracts quickly, and the front coil spring 30 constantly urges the lens frame 10 toward the normal photographing position. Therefore, the lens frame 10 quickly moves to the normal shooting position. Therefore, when this apparatus is mounted on a portable information terminal or the like, the operator can quickly obtain a result of the operation.

As described above, according to the present embodiment, the lens frame 10, the cylindrical support portion 22, the front coil spring 30, and the rear coil spring 40 are arranged concentrically with the optical axis L as the center, and the front surface 21a of the base portion 21 is provided. Since both ends of the front coil spring 30 and the rear coil spring 40 are securely received over the entire circumference by the spring receiving portion 12 and the spring receiving member 50, a substantially uniform force acts on the lens frame 10 in the circumferential direction, It is possible to smoothly move the lens frame 10 in the optical axis direction while realizing downsizing of the apparatus.
Further, since the rear coil spring 40 as the shape memory alloy spring and the lens frame 10 are separated by the cylindrical support portion 22, the heat generated by the rear coil spring 40 is not easily transmitted to the lens G or the optical path, Does not adversely affect the captured image.
Further, since the lens frame 10 is driven by the rear coil spring 40, a complicated drive mechanism is not required, and the apparatus can be greatly reduced in size, and the generation of noise by the drive mechanism can be prevented.
Further, since the lens frame 10 is urged (pressed) from both sides in the optical axis direction by the front coil spring 30 and the rear coil spring 40, the lens frame 10 has a structure resistant to impact.

Next, an example in which a camera unit including the lens driving device is applied to a portable information terminal will be described with reference to FIG.
FIG. 6 shows a mobile phone of a type that can open and close a lid 320 on which a display device is mounted with respect to a main body 310.
The camera unit 300 is mounted on a mounting portion 321 formed on the side surface of the lid portion 320 opposite to the display device. Since the camera unit 300 is downsized, the camera unit 300 can be incorporated in a narrow space such as the mounting portion 321 of the lid portion 320.

7 to 9 show another embodiment of the lens driving device according to the present invention. FIG. 7 is a side view of the device, FIG. 8 is a sectional view in the optical axis direction of the device, and FIG. FIG. 7 to 9, the same reference numerals are used for the same components as in the above embodiment.
As shown in FIGS. 7 to 9, this apparatus holds a lens frame 110 for holding a lens G, a CCD 200 as an imaging device, and a fixed frame 120 for supporting the lens frame 110 movably in the optical axis direction. A coil spring 130 is provided as a shape memory alloy spring of a bidirectional element that is exposed to the outside of a cylindrical support portion 122 (to be described later) of the frame 120 and is concentrically arranged with the optical axis L as the center.

  In this apparatus, the subject light enters the lens G from the optical axis direction and forms an image on the imaging surface of the CCD 200. The camera unit is formed by holding the CCD 200 on the fixed frame 120.

The lens frame 110 is formed in a substantially cylindrical shape with resin, and as shown in FIGS. 7 to 9, the lens G is held inside and slidably fitted on an inner peripheral surface 122 a described later of the fixed frame 120. A cylindrical outer peripheral surface 111 centered on the optical axis L to be joined, an annular support portion 112 disposed outside the outer peripheral surface 111 and rotatably supporting a spring receiving ring 114 described later, and radially from the outer peripheral surface 111 An arm portion 113 that protrudes and is connected to the annular support portion 112, a spring receiving ring 114 that is rotatably supported on the outer peripheral surface of the annular support portion 112 and receives one end of the coil spring 130, and the like.
The annular support portion 112 rotatably supports the spring receiving ring 114 by an annular groove portion 112a formed on the outer peripheral surface thereof.
The arm portion 113 protrudes in the radial direction from the outer peripheral surface 111, and a plurality (three) of the arm portion 113 are formed at equal intervals in the circumferential direction of the annular support portion, and are inserted into a guide hole 123 described later of the fixed frame 120.
The spring receiving ring 114 is fitted in the groove portion 112a of the annular support portion 112, can rotate relatively around the optical axis L with respect to the lens frame 110, and latches an end portion 131 (described later) of the coil spring 130. And an annular receiving surface 114b formed on the rear side in the optical axis direction for receiving one end of the coil spring 130.

The fixed frame 120 is made of resin and delimits the outer contour of the apparatus. As shown in FIGS. 7 to 9, as shown in FIGS. 7 to 9, the base 121 serves as a holding unit that holds the CCD 200. A cylindrical support portion 122 and the like are provided.
The base 121 has a rectangular outer shape, is located in front of the optical axis direction and receives the other end of the coil spring 130, a holding part 121b that holds the CCD 200 inside, and the other end of the coil spring 130, which will be described later. A latching hole 121c for latching 132 is provided.
The cylindrical support portion 122 is formed to extend from the front surface 121a of the base portion 121 in the optical axis direction, and has a cylindrical shape with the optical axis L around which the outer peripheral surface 111 of the lens frame 110 is slidably fitted. A plurality of (three) guide holes 123 and the like that extend rearward in the optical axis direction from the inner peripheral surface 122a and the front end surface 122b and are formed at equal intervals in the circumferential direction are provided.
The cylindrical support portion 122 slidably fits the outer peripheral surface 111 of the lens frame 110 to the inner peripheral surface 122a thereof, thereby supporting the lens frame 110 so as to be movable in the optical axis direction. When the arm portion 113 is inserted through the guide hole 123, the rotation of the lens frame 110 around the optical axis L is restricted and guided so as to be movable in the optical axis direction. Thereby, the lens frame 110 is supported by the cylindrical support part 122 so as to be movable only in the optical axis direction.

The coil spring 130 is a shape memory alloy spring obtained by forming a shape memory alloy wire into a coil shape. As shown in FIGS. 7 to 9, the coil spring 130 is exposed to the outside of the cylindrical support portion 122 and is centered on the optical axis L. The one end of the lens frame 110 is in contact with the spring receiving ring 114 (the annular receiving surface 114b) and the other end is in contact with the front surface 121a of the fixed frame 120.
Further, one end 131 of the coil spring 130 is inserted into the retaining hole 114a of the spring receiving ring 114 and the tip end portion thereof is bent, whereby the coil spring 130 is hooked on the spring receiving ring 114, and the other end 132 is formed. The tip end portion of the fixed frame 120 is hooked to the fixed frame 120 by being inserted into the locking hole 121c and bent.
Further, both ends of the coil spring 130 are electrically connected to the drive circuit 250, and the surface is covered with an electric insulating material (not shown). When the coil spring 130 is energized by the drive circuit 250, the coil spring 130 is heated to a specific temperature region, and the pitch extends by a predetermined length in the optical axis direction. Further, when the energization is stopped, the coil spring 130 is naturally cooled, contracted by a predetermined length in the optical axis direction, and recovered to a shape before being heated. That is, the coil spring 130 expands and contracts in the optical axis direction due to a temperature change caused by energization / non-energization, and drives the lens frame 110 in the optical axis direction.

The operation of the lens driving device will be described. When the lens frame 110 of the lens driving device is in the normal photographing position, the lens frame 110 is retracted rearward in the optical axis direction as shown in FIGS. It is out. In order to move the lens frame 110 forward from this position toward the front in the optical axis direction and move it to the close-up photographing position, the coil spring 130 is energized by the drive circuit 250.
When the coil spring 130 is energized, the coil spring 130 is heated by its electric resistance and extends in the optical axis direction to move the lens frame 110 to a close-up photographing position (not shown). At this time, when the length of the spring material of the coil spring 130 is also extended to generate a rotation component around the optical axis L, the spring receiving ring 114 is rotated relative to the lens frame 110 and the coil spring 130 is rotated. Only the extension component of the pitch is transmitted to the lens frame 110. Therefore, the lens frame 110 moves smoothly in the optical axis direction.
In order to move the lens frame 110 from the close-up shooting position to the normal shooting position, the energization of the coil spring 130 by the drive circuit 250 is stopped. When the energization is stopped, the temperature of the coil spring 130 decreases due to natural cooling and contracts in the optical axis direction. At this time, since both end portions 131 and 132 of the coil spring 130 are respectively engaged with the spring receiving ring 114 and the fixed frame 120, the lens frame 110 is retracted toward the rear in the optical axis direction by the contraction of the coil spring 130. The normal shooting position is reached. If the coil spring 130 that contracts has a rotating component, the spring receiving ring 114 rotates.

  As described above, according to the present embodiment, since the lens driving device can be configured by the lens frame 110, the fixed frame 120, and the coil spring 130 as the shape memory alloy spring, the device can be further miniaturized. Further, since the coil spring 130 and the lens frame 110 are separated by the cylindrical support portion 122, the heat generated by the coil spring 130 is not easily transmitted to the lens G and the optical path, and does not adversely affect the captured image. Furthermore, by providing the spring receiving ring 114, the rotational component of the coil spring 130 can be absorbed smoothly.

  In the above embodiment, the rear coil spring 40 and the coil spring 130 are configured to expand when heated, and contract when cooled, but are not limited thereto, and contract and cool when heated. Then, it is possible to adopt a configuration that expands.

  In the above embodiment, the rear coil spring 40 is made of a shape memory alloy. However, the present invention is not limited to this, and the front coil spring 30 can be made of a shape memory alloy instead of the rear coil spring 40. Further, both the front coil spring 30 and the rear coil spring 40 can be made of a shape memory alloy. In the case where both the front coil spring 30 and the rear coil spring 40 are made of a shape memory alloy, when one of them is energized and heated to expand, the other is energized and heated to contract.

  In the above embodiment, the CCD 200 is held by the fixed frames 20 and 120. However, the present invention is not limited to this, and the CCD 200 may be provided on the portable information terminal side.

  In the above-described embodiment, the lens frames 10 and 110 are positioned at the normal shooting position and the close-up shooting position by the amount of expansion and contraction of the rear coil spring 40 or the coil spring 130. However, the present invention is not limited to this. , 110 may be provided on the fixed frames 20, 120 or the like, or may be formed integrally with the positioning members that define the normal shooting position and the close-up shooting position.

In the above embodiment, the lens frame 110 is provided with the spring receiving ring 114 and the one end 131 of the coil spring 130 is pivotably hooked. However, the present invention is not limited to this.
A structure in which the spring receiving ring is provided on the fixed frame side is also possible. Further, without using the spring receiving ring 114, it is possible to form a long hole or the like for rotatably engaging the one end portion 131 of the coil spring 130 in the annular support portion 112. It is also possible to form a long hole or the like in the fixed frame 120 for hooking the one end 131 directly on the lens frame 110 and pivoting the other end 132.

  In the above-described embodiment, the case of the lens driving device for macro switching has been described. However, the present invention is not limited to this, and the lens driving device can be used for zooming or focusing.

  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 side view which shows one Embodiment of the lens drive device which concerns on this invention. It is sectional drawing of the optical axis direction of the apparatus with a lens frame in a normal imaging position. It is a disassembled perspective view of a lens drive device. It is a side view of an apparatus in which a lens frame is in a close-up shooting position. It is sectional drawing of the optical axis direction of the apparatus with a lens frame in a close-up photography position. It is a general-view perspective view of the mobile telephone carrying the lens drive device based on this invention. It is a side view which shows other embodiment of the lens drive device which concerns on this invention. It is sectional drawing of the optical axis direction of the apparatus which concerns on other embodiment. It is a disassembled perspective view of the lens drive device concerning other embodiments.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Lens frame 11 ... Outer peripheral surface 12 ... Spring receiving part 12a, 12b ... Receiving surface 13 ... Arm part 20 ... Fixed frame 21 ... Base 21a ... Front surface 22 ... Cylindrical support part 22a ... Inner peripheral surface 22b ... Front end surface 22c ... Projection 23 ... Guide hole 30 ... Front coil spring 40 ... Rear coil spring (shape memory alloy spring)
50 ... spring receiving member 50a ... fitting hole 110 ... lens frame 111 ... outer peripheral surface 112 ... annular support 112a ... groove 113 ... arm 114 ... spring receiving ring 114a ... retaining hole 114b ... receiving surface 120 ... fixed frame 121 ... Base 121a ... Front 121b ... Holding part 121c ... Locking hole 122 ... Cylindrical support 123 ... Guide hole 130 ... Coil spring (shape memory alloy spring)
200 ... CCD
250 ... Drive circuit 300 ... Camera unit 310 ... Main body 320 ... Lid 321 ... Mount G ... Lens L ... Optical axis

Claims (2)

A lens frame that holds the lens, a fixed frame that has a cylindrical support portion that supports the lens frame so as to be movable only in the optical axis direction, and a coil spring that can expand and contract in the optical axis direction.
The coil spring is concentrically exposed and arranged outside the cylindrical support portion, and is formed of a shape memory alloy so as to expand and contract in the optical axis direction due to a temperature change caused by energization / non-energization to generate a driving force. the shape memory alloy spring seen including,
The coil spring includes a front coil spring and a rear coil spring arranged in contact with each other to urge the lens frame from the front side and the rear side in the optical axis direction,
At least one of the front coil spring and the rear coil spring is the shape memory alloy,
The lens frame includes an arm portion protruding in a radial direction from an outer peripheral surface thereof, and an annular shape connected to the arm portion and disposed outside the cylindrical support portion to receive one end of the front coil spring and the rear coil spring. A spring receiver,
The cylindrical support part has a guide hole formed to extend in the optical axis direction so as to allow the arm part to be inserted therethrough.
A lens driving device. A lens frame that holds the lens, a fixed frame that has a cylindrical support portion that supports the lens frame so as to be movable only in the optical axis direction, and a coil spring that can expand and contract in the optical axis direction.
The coil spring is concentrically exposed and arranged outside the cylindrical support portion, and is formed of a shape memory alloy so as to expand and contract in the optical axis direction due to a temperature change caused by energization / non-energization to generate a driving force. Including shape memory alloy springs,
One end of the shape memory alloy spring is hooked to one of the fixed frame and the lens frame so as to be relatively rotatable around the optical axis, and the other end is hooked to the other of the fixed frame and the lens frame,
The lens frame includes an arm portion projecting in a radial direction from an outer peripheral surface thereof, an annular support portion connected to the arm portion and disposed outside the cylindrical support portion, and an optical axis around the annular support portion. A spring receiving ring that is rotatably supported by the shape memory alloy spring, and one end of the shape memory alloy spring is hooked.
The cylindrical support part has a guide hole formed to extend in the optical axis direction so as to allow the arm part to be inserted therethrough.
Features and, Relais lens driving device that.

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