JP2013077031A - Actuator, driving device and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an actuator able to reduce power consumption by improving heat efficiency, and to provide a driving device and imaging apparatus that use the actuator.SOLUTION: The actuator comprises a fixed part, a first movable part, a second movable part and a conductive part. Here, the first movable part is composed by arranging a plurality of parts in layers. The plurality of parts include: a first beam part provided with respect to the fixed part; a first force generation part for generating force according to the application of heat; and a first heat generation part for generating heat according to the supply of current. The first movable part is deformed according to heat generation in the first heat generation part. The second movable part is composed by arranging a plurality of parts in layers. The plurality of parts include a second beam part provided with respect to the fixed part; a second force generation part for generating force according to heat generation; and a second heat generation part for generating heat according to the supply of current. The second movable part is deformed according to the heat generation in the second heat generation part. The conductive part electrically connects the first and second heat generation parts, and is lower in electric resistance per unit length than the first and second heat generation parts.

Description

  The present invention relates to an actuator, and a driving device and an imaging device using the actuator.

  In recent years, functions of a digital camera have come to be standardly installed in portable electronic devices typified by cellular phones. For such portable electronic devices, further reduction in size and weight is always required, and reduction in size and weight of the camera module is inevitably required. On the other hand, for camera modules mounted on portable electronic devices, it is required to enhance functions such as an autofocus function and a camera shake correction function.

  In order to increase the functionality of such a camera module, an actuator for driving an optical system and a mechanical mechanism is indispensable, and an actuator for realizing higher functionality while satisfying the demand for reduction in size and weight is required.

  In response to such requirements, actuators using bimetals and small actuators using shape memory alloys have been proposed (for example, Patent Documents 1 and 2). In such an actuator, since driving force is generated by heating and cooling, it is necessary to improve the heating rate and the cooling rate for the purpose of improving responsiveness.

JP 2004-255614 A JP 2007-193248 A

  However, the techniques of Patent Documents 1 and 2 do not consider the thermal efficiency except for the portion to be heated in order to generate the driving force, and increase in power consumption due to the decrease in thermal efficiency due to the generation of heat loss. Invite.

  The present invention has been made in view of the above problems, and an object thereof is to provide an actuator capable of reducing power consumption due to an increase in thermal efficiency, and a drive device and an imaging device using the actuator. .

  In order to solve the above-described problem, an actuator according to a first aspect includes a fixed portion, a first beam portion provided for the fixed portion, a first force generating portion that generates a force in response to heating, A plurality of portions including a first heat generating portion that generates heat in response to current supply are stacked, and a first movable portion that deforms in response to heat generated in the first heat generating portion, and the fixed portion A plurality of portions including a second beam portion to be provided, a second force generating portion that generates force in response to heating, and a second heat generating portion that generates heat in response to supply of current are stacked and configured. The second movable part deforming according to the heat generation in the second heat generating part, the first heat generating part and the second heat generating part are electrically connected, and the unit is more unit than the first and second heat generating parts. A conductive portion having a low electrical resistance per length.

  The actuator which concerns on a 2nd aspect is an actuator which concerns on a 1st aspect, Comprising: The said 1st and 2nd force generation part contains a shape memory alloy.

  An actuator according to a third aspect is the actuator according to the first aspect, wherein the first and second force generation units have a thermal expansion coefficient higher than that of the first and second beam parts. Have.

  A drive device according to a fourth aspect includes an actuator according to any one of the first to third aspects, and a moving object that is moved by deformation of the first and second movable parts.

  An imaging device according to a fifth aspect includes the actuator according to any one of the first to third aspects, an imaging element, and an optical system that guides light from a subject to the imaging element, and the imaging element and At least one of the optical systems is moved by deformation of the first and second movable parts.

  The drive device according to the sixth aspect includes a fixed portion, a first beam portion provided for the fixed portion, a first force generating portion that generates a force in response to heating, and heat generation in response to a current supply. A plurality of portions including a first heat generating portion to be stacked and configured to be deformed in response to heat generated in the first heat generating portion; a second beam portion provided to the fixed portion; A plurality of parts including a second force generating part that generates a force in response to heating and a second heat generating part that generates heat in response to a current supply are stacked, and in response to heat generated in the second heat generating part. An actuator layer including a deformable second movable portion; and the first heat generating portion and the second heat generating portion are electrically connected, and the electric power per unit length is greater than that of the first and second heat generating portions. It is moved by the conductive layer having low resistance and the first and second movable parts. And a dynamic object.

  An imaging device according to a seventh aspect includes the drive device according to the sixth aspect, includes an imaging device and an optical system that guides light from a subject to the imaging device, and the moving object is the imaging device. And at least one of the optical systems.

  With the actuator according to any of the first to third aspects, heat generation is suppressed in the wiring that electrically connects the first heat generating portion and the second heat generating portion, so that power consumption is reduced due to an increase in thermal efficiency. be able to.

  In any of the drive device according to the fourth aspect and the imaging device according to the fifth aspect, in the wiring that electrically connects the first heat generating part and the second heat generating part when moving the moving object Since heat generation is suppressed, power consumption can be reduced due to an increase in thermal efficiency.

  With the driving devices according to any of the sixth and seventh aspects, when moving the object to be moved, heat generation is suppressed in the wiring that electrically connects the first heat generating unit and the second heat generating unit. Power consumption can be reduced by increasing the thermal efficiency.

It is a schematic diagram which shows schematic structure of the mobile telephone carrying the camera module which concerns on one Embodiment of this invention. It is a cross-sectional schematic diagram paying attention to the 1st housing | casing which concerns on one Embodiment of this invention. It is a cross-sectional schematic diagram of the camera module which concerns on one Embodiment of this invention. It is the external view which looked at the camera module which concerns on one Embodiment of this invention from the side. It is the external view which looked at the camera module which concerns on one Embodiment of this invention from the side. It is a cross-sectional schematic diagram of a lens group. It is a cross-sectional schematic diagram of a lens group. It is the external view which looked at the 1st lens constituent layer from the lower part. It is the external view which looked at the 2nd lens constituent layer from the upper part. It is a figure for demonstrating the shape of a spacer layer. It is the external view which looked at the lens position adjustment layer from the upper part. It is the external view which looked at the lens position adjustment layer from the side. It is the external view which looked at the actuator layer from the upper part. It is the external view which looked at the actuator layer from the side. It is a figure which shows the shape of the base layer which comprises an actuator layer. It is a figure which shows the shape of the actuator element layer which comprises an actuator layer. It is a figure which shows the shape of the 1st insulating layer which comprises an actuator layer. It is a figure which shows the shape of the heater layer which comprises an actuator layer. It is a figure which shows the shape of the conductive layer which comprises an actuator layer. It is a figure which shows the shape of the 2nd insulating layer which comprises an actuator layer. It is a figure for demonstrating the operation example of a movable part. It is a figure for demonstrating the operation example of a movable part. It is the external view which looked at the 2nd parallel spring from the downward direction. It is a figure which shows the 2nd parallel spring with which the lens group was mounted | worn. It is the external view which looked at the 1st parallel spring from the lower part. It is a figure which shows the 1st parallel spring with which the lens group was mounted | worn. It is a flowchart which shows the manufacturing process of a camera module. It is a figure which shows typically a mode that the prepared sheet | seat etc. are laminated | stacked and joined. It is a cross-sectional schematic diagram of the camera module which concerns on the modification of this invention. It is a figure which shows the shape of the electroconductive frame layer which concerns on the modification of this invention. It is the external view which looked at the actuator layer which concerns on the modification of this invention from upper direction. It is a figure which shows the shape of the base layer which concerns on the modification of this invention. It is a figure which shows the shape of the actuator element layer which concerns on the modification of this invention. It is a figure which shows the shape of the 1st insulating layer which concerns on the modification of this invention. It is a figure which shows the shape of the heater layer which concerns on the modification of this invention. It is a figure which shows the shape of the conductive layer which concerns on the modification of this invention. It is a figure which shows the shape of the 2nd insulating layer which concerns on the modification of this invention. It is a figure which shows the aspect which moves the image pick-up element which concerns on the modification of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

<(1) Schematic configuration of mobile phone>
FIG. 1 is a schematic diagram showing a schematic configuration of a mobile phone 100 equipped with a camera module 500 according to an embodiment of the present invention. In FIG. 1 and the drawings after FIG. 1, three axes XYZ orthogonal to each other are appropriately attached in order to clarify the orientation relationship.

  As shown in FIG. 1, the mobile phone 100 is configured as a foldable mobile phone, and includes a first housing 200, a second housing 300, and a hinge part 400. Each of the first casing 200 and the second casing 300 has a plate-like substantially rectangular parallelepiped shape and serves as a casing for storing various electronic members. Specifically, the first casing 200 includes a camera module 500 and a display, and the second casing 300 includes a control unit that electrically controls the mobile phone 100 and an operation member such as a button. Have. In addition, the hinge part 400 has connected the 1st housing | casing 200 and the 2nd housing | casing 300 so that rotation is possible. For this reason, the mobile phone 100 can be folded.

  FIG. 2 is a schematic cross-sectional view focusing on the first casing 200 of the mobile phone 100. As shown in FIG. 1 and FIG. 2, the camera module 500 is a small imaging device, so-called micro camera unit, having an XY cross section of about 5 mm square and a thickness (depth in the Z direction) of about 3 mm. (MCU).

  Hereinafter, the configuration of the camera module 500, the manufacturing process of the camera module 500, and lens driving in the camera module 500 will be sequentially described.

<(2) Configuration of camera module>
FIG. 3 is a schematic cross-sectional view of the camera module 500, and the direction indicated by the arrow AR1 in FIG. 3 corresponds to the + Z direction. In the drawings subsequent to FIG. 3, an arrow AR <b> 1 indicating a direction corresponding to the + Z direction is appropriately attached in order to clarify the orientation relationship. 4 and 5 are side views of the camera module 500 as viewed from the side.

  As shown in FIG. 3, the camera module 500 includes an optical unit KB in which a lens group 20 as a photographing optical system is movably provided, and an imaging unit PB that acquires a photographed image related to a subject image. Yes.

  The imaging unit PB has a configuration in which, for example, an imaging element layer 18 having an imaging element 181 such as a COMS sensor or a CCD sensor, and a cover glass layer 17 are stacked in this order in the + Z direction. The cover glass layer 17 may include a filter layer that cuts infrared rays (IR).

  The optical unit KB includes a lid layer 10, a first frame layer 11, a first parallel spring (upper parallel spring) 12, a second frame layer 13, a second parallel spring (lower parallel spring) 14, an actuator layer 15, and lens position adjustment. The layer 16 and the lens group 20 are provided. The lid layer 10, the first frame layer 11, the first parallel spring 12, the second frame layer 13, the second parallel spring 14, the actuator layer 15, the lens position adjustment layer 16, and the lens group 20 are all in a wafer state (wafer Produced by level). These manufacturing processes will be described later.

  In the optical unit KB, the lens position adjusting layer 16, the actuator layer 15, the second parallel spring 14, the second frame layer 13, the first parallel spring 12, the first frame layer 11, and the lid layer 10 are arranged in this order in the + Z direction. The lens group 20 is held between the second parallel spring 14 and the first parallel spring 12. The first parallel spring 12, the second parallel spring 14, and the actuator layer 15 cooperate with each other to move the lens group 20 in the direction along the Z axis.

  In the camera module 500, the lid layer 10, the first and second frame layers 11 and 13, the lens position adjustment layer 16, the cover glass layer 17, and the imaging element layer 18 serve as a fixing portion for the lens group 20. The camera module 500 and the optical unit KB are manufactured in a wafer state (at the wafer level), and four side surfaces thereof (side surfaces parallel to the Z axis in FIGS. 4 and 5) are cut surfaces formed by dicing. ing. And in this cut surface, the laminated structure of the multiple layer which comprises the optical unit KB and the imaging part PB is exposed.

  Here, the lens group 20 is supported by the first and second parallel springs 12 and 14 coupled to the fixed portion. More specifically, the second parallel spring 14 is interposed between the actuator layer 15 and the lens group 20 on the −Z side (the side on which the image sensor 181 is disposed) of the lens group 20. Further, a first parallel spring 12 is interposed between the first frame layer 11 and the lens group 20 on the + Z side (the side where the lid layer 10 is disposed) of the lens group 20. That is, the lens group 20 is sandwiched between the first parallel spring 12 and the second parallel spring 14. Here, since the lens group 20 is clamped by the first and second parallel springs 12 and 14, the posture of the lens group 20 is maintained regardless of the movement of the lens group 20, and the optical axis of the lens group 20 is substantially constant. Retained.

  Further, the first and second parallel springs 12 and 14 apply a force in a direction opposite to the moving direction of the lens group 20 (that is, the + Z direction) when the lens group 20 as the moving object moves in the + Z direction. The lens group 20 is given. When the lens group 20 moves in the −Z direction, the direction of the force applied to the lens group 20 by the first and second parallel springs 12 and 14 is the moving direction of the lens group 20 (that is, −Z). Direction).

  Further, in a non-driving state in which the lens group 20 is not moving in the + Z direction (for example, a stationary state before driving), the lens group 20 is moved by the elastic force of the first and second parallel springs 12 and 14 from the lens position adjusting layer 16. The lens group 20 is supported by the lens position adjusting layer 16 by being pressed against the upper end surface of the protrusion 162. In this non-driven state, the lens group 20 is disposed at a predetermined position on the most −Z side of the range (displaceable range) that can be displaced along the Z axis and is stationary.

  The predetermined position is, for example, a position where the focal point of the optical unit KB is disposed on the + Z side surface (hereinafter also referred to as “imaging surface”) on which a large number of pixel circuits are arranged in the image sensor 181. Is set. Here, the focal point of the optical unit KB refers to a point where light beams emitted from the optical unit KB gather at one point when parallel light beams enter the optical unit KB from the + Z side.

  Further, as described above, in the non-driven state, the lens group 20 is pressed against the lens position adjustment layer 16 by the elastic force of the first and second parallel springs 12 and 14, and thus is strong against the camera module 500. Even when an impact is applied, the posture of the lens group 20 is maintained.

  The actuator layer 15 as an actuator has movable parts 15 a and 15 b (FIG. 13) that generate drive displacement in the + Z direction, and is disposed on the −Z side of the lens group 20. The movable portions 15 a and 15 b are in contact with the first protrusion 201 protruding to the −Z side of the lens group 20, and the drive displacement generated in the movable portions 15 a and 15 b is transmitted to the lens group 20 via the first protrusion 201. Is done. That is, the actuator layer 15 moves the lens group 20 that is the moving object in a predetermined direction (here, the + Z direction) by its deformation. In a scene where the drive displacement in the + Z direction in the movable portions 15a and 15b is reduced, the lens group 20 is moved in a direction opposite to the predetermined direction (−Z by the elastic force of the first and second parallel springs 12 and 14). Direction).

  The side wiring 21 is a thin conductive member disposed on one of the four side surfaces of the camera module 500. As shown in FIGS. 4 and 5, the side wiring 21 is electrically connected to the heater layer 154 (FIG. 18) and an external current supply source (not shown) via the imaging element layer 18. Examples of the external current supply source include a driver that controls a current supplied in accordance with a signal from a control unit (not shown). Further, an insulating portion 14ep is provided between the second parallel spring 14 and the side wiring 21 so that the side wiring 21 and the second parallel spring 14 are not short-circuited.

  As described above, in the camera module 500, the lens group 20 that is a moving object is coupled to the first and second parallel springs 12 and 14 disposed at positions facing each other via the lens group 20, The first and second parallel springs 12 and 14 are elastically deformed in a direction perpendicular to the lens group 20 (+ Z direction), and hold the posture of the lens group 20. The lens group 20 receives a driving force from the movable portions 15a and 15b of the actuator layer 15 and displaces the position along the Z axis. Therefore, the optical unit KB provided in the camera module 500 can displace the lens group 20 in the optical axis direction (Z-axis direction) of the lens group 20, and the camera module serves as a driving device for displacing the lens group 20. Make 500 work.

<(2-1) Lens group>
The lens group 20 is manufactured at a wafer level using a glass substrate as a base material, and is formed by, for example, superposing two or more lenses. In the present embodiment, a case where the lens group 20 is configured by overlapping two optical lenses is illustrated. In the present embodiment, the lens group 20 functions as an imaging lens that guides light from the subject to the imaging element 181.

  6 and 7 are schematic cross-sectional views of the lens group 20, and the direction indicated by the arrow AR2 corresponds to the + Z direction. 8 is a bottom external view of the lens group 20 when the lens group 20 is viewed from below (−Z side), and FIG. 9 is a top external view of the lens group 20 when the lens group 20 is viewed from above (+ Z side). It is.

  As shown in FIGS. 6 and 7, the lens group 20 includes a first lens constituent layer LY1 having a first lens G1, a second lens constituent layer LY2 having a second lens G2, and a spacer layer RB. . Then, the first lens constituent layer LY1 and the second lens constituent layer LY2 are coupled via the spacer layer RB. Here, the outer edges of the non-lens portions of the first and second lens constituent layers LY1, LY2 have a substantially square shape.

  As shown in FIGS. 6 to 8, the first main surface (here, −Z side) of the first lens constituent layer LY1 having the first lens G1 has a first non-lens portion that does not function as a lens. A protrusion 201 is provided. Furthermore, as shown in FIGS. 6, 7, and 9, a non-lens portion that does not function as a lens is provided on one main surface (here, + Z side) of the second lens constituent layer LY <b> 2 having the second lens G <b> 2. A second protrusion 202 is provided.

  FIG. 10 is a view of the spacer layer RB as viewed from above (+ Z side), focusing on the shape of the spacer layer RB. As shown in FIG. 10, the spacer layer RB is provided along the outer edge of the non-lens portion of the first and second lens constituting layers LY1 and LY2, and the outer edge and the inner edge of the XY cross section are rectangular in shape. It has a configuration. Then, the optical axis of the lens group 20 is set in a direction along the Z axis.

<(2-2) About each functional layer>
Below, the detail of each functional layer which comprises the camera module 500 is demonstrated. For each functional layer, the −Z side surface is referred to as one main surface, and the + Z side surface is referred to as the other main surface.

<(2-2-1) Image sensor layer>
As shown in FIG. 3, the image sensor layer 18 receives light from the subject that has passed through the optical unit KB, and generates an image signal related to the image of the subject, its peripheral circuit, and the image sensor 181. It is a member provided with the outer peripheral part which surrounds. The image sensor 181 is configured by arranging a large number of pixel circuits. Note that a solder ball HB for performing reflow soldering is provided on one main surface (the surface on the −Z side) of the imaging element layer 18. Although not shown here, various types of wiring for applying a signal to the image sensor 181 and reading a signal from the image sensor 181 are connected to one main surface of the image sensor layer 18. A terminal is provided.

<(2-2-2) Cover glass layer>
As shown in FIG. 3, the cover glass layer 17 has a substantially flat plate shape and an XY cross section having a substantially square shape, and is made of transparent glass or the like. The cover glass layer 17 is bonded to the other main surface (+ Z side surface) of the image sensor layer 18 and has a function of protecting the image sensor 181. The image sensor substrate 178 is configured with the cover glass layer 17 bonded to the image sensor layer 18.

<(2-2-3) Lens position adjustment layer>
The lens position adjustment layer 16 is configured by using a resin material, is disposed between the image sensor 181 and the lens group 20, and is a member that adjusts the distance between the image sensor 181 and the lens group 20. Specifically, the lens position adjustment layer 16 defines the position (initial position) of the lens group 20 in the non-driven state. The lens position adjustment layer 16 is generated using, for example, a method of etching a resin.

  FIG. 11 is a top view of the lens position adjusting layer 16 as seen from above (+ Z side). FIG. 12 is a side view of the lens position adjusting layer 16 when the lens position adjusting layer 16 is viewed from the side. As shown in FIGS. 11 and 12, the lens position adjustment layer 16 includes a frame body 161 and a protrusion 162.

  The frame 161 is a substantially rectangular annular portion that constitutes the outer peripheral portion of the lens position adjusting layer 16, and has a plate-like shape substantially parallel to the XY plane. The frame 161 forms a hole (through-hole) 16H penetrating in the direction along the Z axis, and the + Y side plate-like member and the −Y side plate-like member constituting the frame 161 are: Each has a protruding portion 161T that protrudes toward the through hole 16H. Further, one main surface of the frame body 161 is bonded to the adjacent cover glass layer 17, and the other main surface of the frame body 161 is connected to the adjacent actuator layer 15 (specifically, the frame body 15 f of the actuator layer 15 ( FIG. 13)).

  The protrusion 162 is erected upward (in the + Z direction) in the vicinity of the inner edge of the convex portion 161T constituting the frame body 161. The projection 162 is a plate-like portion having a substantially rectangular board surface substantially parallel to the XZ plane, and the longitudinal direction of the projection 162 is a direction substantially parallel to the X axis, and the short direction of the projection 162 Is a direction substantially parallel to the Z-axis. The end surface on the + Z side of the protrusion 162 has a function of placing the lens group 20 at the initial position when the lens group 20 comes into contact therewith.

  In FIG. 11, a region (pixel array region) in which a plurality of pixel circuits constituting the image sensor 181 are arranged, that is, an outer edge of the front surface (imaging surface) of the image sensor 181 is indicated by a broken line. As shown in FIG. 11, the imaging surface is configured such that the relationship of (short side length) :( long side length) :( diagonal length) = 3: 4: 5 is established. . The protrusion 162 is disposed at a position that sandwiches the optical path from the subject through the lens group 20 to the pixel array region of the image sensor 181 in the direction in which the width of the pixel array region is the narrowest. That is, the protrusion 162 is installed so as not to adversely affect the photographing and increase the size of the apparatus.

<(2-2-4) Actuator layer>
FIG. 13 is a top view of the actuator layer 15 as seen from above (+ Z side). FIG. 14 is a side view of the actuator layer 15 as seen from the side. 15 to 20 are diagrams showing the configuration of each layer constituting the actuator layer 15.

  As shown in FIG. 13, the actuator layer 15 includes a frame body 15 f constituting an outer peripheral portion, and two plate-like movable portions that protrude from the frame body 15 f with respect to a hollow portion inside the frame body 15 f. 15a and 15b. The actuator layer 15 includes a base layer 151 (FIG. 15), an actuator element layer 152 (FIG. 16), a first insulating layer 153 (FIG. 17), a heater layer 154 (FIG. 18), a conductive layer 155 (FIG. 19), And the 2nd insulating layer 156 (FIG. 20) is laminated | stacked in this order from -Z side to + Z side, and is comprised.

  The base layer 151 includes a base frame 151f as a fixing portion constituting the frame 15f, and two plate-like protrusions protruding from the base frame 151f with respect to a hollow portion inside the base frame 151f. The units 151a and 151b are provided. Here, the protruding portion 151a as the beam portion constitutes the movable portion 15a, and the protruding portion 151b as the beam portion constitutes the movable portion 15b. The base layer 151 is made of a material having a low coefficient of thermal expansion such as silicon.

  The actuator element layer 152 includes a force generator 152a that constitutes the movable portion 15a, and a force generator 152b that constitutes the movable portion 15b. The force generators 152a and 152b are made of a material having characteristics different from those of the base layer 151, and generate force by being deformed in response to heating. Here, the description will be made assuming that the force generators 152a and 152b are made of a shape memory alloy (SMA). The force generation part 152a is formed so as to cover the entire area of the + Z side main surface (other main surface) of the protruding part 151a by a technique such as sputtering or vapor deposition. Similarly, the force generator 152b is formed so as to cover the entire area of the + Z side main surface (other main surface) of the protruding portion 151b by a technique such as sputtering or vapor deposition.

  The first insulating layer 153 is made of an insulator such as an oxide film (silicon dioxide or the like). The first insulating layer 153 is formed by a technique such as sputtering or vapor deposition so as to cover the main surface (the other main surface) on the + Z side of the base frame 151f and the actuator element layer 152, as shown in FIG. The

  The heater layer 154 is made of a conductive metal such as platinum having a high resistivity. The heater layer 154 is formed on the + Z side main surface (the other main surface) of the first insulating layer 153 by a photolithography technique generally used in a semiconductor manufacturing process or the like. As shown in FIG. 18, the heater layer 154 is provided in a shape like one elongated wiring. Specifically, in the heater layer 154, the wiring portion 1541, the heater portion 154a, the wiring portion 1542, the heater portion 154b, and the wiring portion 1543 are extended in this order, and are sequentially electrically connected. The wiring portions 1541, 1542, and 1543 constitute the frame 15f, the heater portion 154a constitutes the movable portion 15a, and the heater portion 154b constitutes the movable portion 15b.

  Specifically, as shown in FIG. 18, the heater portion 154a is fixed from one end (fixed end) to the frame 15f of the movable portion 15a to the other end (free end) of the movable portion 15a. It extends over the vicinity of the FT, is folded back near the free end FT, and extends from the vicinity of the free end FT to the fixed end. Similarly, the heater portion 154b extends from one end portion (fixed end) fixed to the frame 15f of the movable portion 15b to the vicinity of the other end portion (free end) FT of the movable portion 15b. It is folded near the free end FT and extends from the free end FT to the fixed end.

  The conductive layer 155 is made of a conductor having a relatively lower resistivity than the material constituting the heater layer 154, such as copper. The conductive layer 155 is formed on the + Z side main surface (other main surface) of the first insulating layer 153 and the heater layer 154 by a photolithography technique generally used in a semiconductor manufacturing process or the like. As shown in FIG. 19, the conductive layer 155 includes a first conductive portion 1551 that covers the + Z side main surface (other main surface) of the wiring portion 1541, and a + Z side main surface (other main surface) of the wiring portion 1542. The second conductive portion 1552 is covered, and the third conductive portion 1553 is formed to cover the main surface (other main surface) on the + Z side of the wiring portion 1543. That is, the conductive layer 155 covers substantially the entire area of the heater layer 154 on the + Z side main surface (other main surface) except the heater portion 154a and the heater portion 154b. Further, the first to third conductive portions 1551 to 1553 are provided separately, and constitute a frame 15f. Furthermore, the widths of the first to third conductive portions 1551 to 1553 are all the same as the width of the frame 15f, and the thickness of the first to third conductive portions 1551 to 1553 is larger than the thickness of the heater layer 154. Is relatively thick.

  The first conductive portion 1551 is provided from the outer edge to the vicinity of the inner edge of the frame 15f, covers the + Z side main surface (other main surface) of the wiring portion 1541, and one end portion of the first conductive portion 1551 is the heater portion 154a. Is electrically connected to one end of the. And the other end part which forms the outer edge of the frame 15f of the 1st electroconductive part 1551 forms the electrode part 1551S electrically connected with the side wiring 21. FIG. That is, the first conductive portion 1551 functions as a conductive portion that electrically connects the electrode portion 1551S to which the side wiring 21 is electrically connected and one end portion of the heater portion 154a.

  The second conductive portion 1552 covers a substantially entire area of the main surface (other main surface) on the + Z side of the wiring portion 1542 and electrically connects the other end portion of the heater portion 154a and one end portion of the heater portion 154b. Function as. The second conductive portion 1552 is + X from the outer edge portion on the −X side of the actuator layer 15 (here, the outer edge portion where the electrode portion 1551S is formed) so that a short circuit does not occur due to contact with the side wiring 21. It is formed toward the + X direction from a position slightly separated in the direction.

  The third conductive portion 1553 covers substantially the entire area of the main surface (other main surface) on the + Z side of the wiring portion 1543, and one end portion of the third conductive portion 1553 is electrically connected to the other end portion of the heater portion 154b. Is done. The other end portion of the third conductive portion 1553 that forms the outer edge of the frame body 15f forms an electrode portion 1553S that is electrically connected to the side surface wiring 21. That is, the third conductive portion 1553 functions as a conductive portion that electrically connects the electrode portion 1553S to which the side wiring 21 is electrically connected and the other end portion of the heater portion 154b.

  The second insulating layer 156 is made of an insulator such as an oxide film (silicon dioxide or the like). As shown in FIG. 20, the second insulating layer 156 has a main surface (other main surface) on the + Z side of the first insulating layer 153, the heater layer 154, and the conductive layer 155, as shown in FIG. It is formed to cover.

  With such a configuration of the actuator layer 15, the heater layer 154 and the conductive layer 155 form a wiring through which a current flows between the electrode portion 1551S and the electrode portion 1553S. In this wiring, the electric resistances of the first to third conductive parts 1551 to 1553 are relatively lower than the electric resistances of the heater parts 154a and 154b. Specifically, when the direction in which the current flows in the wiring that electrically connects the electrode portion 1551S and the electrode portion 1553S is the extending direction of the wiring, the unit length in the extending direction of the first to third conductive portions 1551 to 1553 The electric resistance per unit is relatively lower than the electric resistance per unit length in the extending direction of the heater portions 154a and 154b. Therefore, when a voltage is applied between the electrode portion 1551S and the electrode portion 1553S and a current flows through the wiring formed of the heater layer 154 and the conductive layer 155, the electric resistance is relatively higher than that of the other portions. The heaters 154a and 154b generate heat due to their own Joule heat. That is, the heater portions 154a and 154b as the heat generating portions generate heat in response to current supply. On the other hand, in the wiring composed of the heater layer 154 and the conductive layer 155, the portion excluding the heater portions 154a and 154b has an electric resistance lower than that of the heater portions 154a and 154b. The

  Further, the actuator layer 15 is subjected to a process (shape memory process) in which the movable parts 15a and 15b are set in a mold having a shape to be memorized and heated at a predetermined temperature (for example, 600 ° C.). The SMA constituting the actuator element layer 152 has a characteristic of being restored to a predetermined shape (also referred to as “memory shape”) stored in advance when heated to exceed a predetermined phase transformation temperature and reach a predetermined temperature. Here, a warped shape in which the free ends FT of the movable portions 15a and 15b are displaced upward (+ Z direction) is stored. Therefore, when the SMA is heated by energization of the heater layer 154 and the conductive layer 155, the SMA is deformed so as to be restored to the memory shape while being contracted, and the free ends FT of the movable portions 15a and 15b are moved upward (in the + Z direction). ).

  FIG. 21 and FIG. 22 are schematic views showing in a simplified manner how the movable portions 15a and 15b are deformed in accordance with the heat generated by the heater layer 154 (specifically, the heater portions 154a and 154b). In addition, since the deformation | transformation aspect of the movable parts 15a and 15b is respectively the same, in FIG.21 and FIG.22, the deformation | transformation aspect of the movable part 15a is shown as an example. As shown in FIG. 21, the movable portion 15a has a flat shape when the heater portion 154a is not generating heat. On the other hand, as shown in FIG. 22, a force is generated by the deformation of the force generator 152a in response to the heat generated by the heater 154a, and the movable portion 15a is fixed to the frame 15f. With the vicinity of the (fixed end) as a fulcrum, deformation occurs such that the free end FT is displaced upward (+ Z direction).

<(2-2-5) Second parallel spring>
FIG. 23 is a bottom external view of the second parallel spring 14 when the second parallel spring 14 is viewed from below (−Z direction). FIG. 24 is a diagram showing the second parallel spring 14 joined to the lens group 20. As shown in FIG. 23, the second parallel spring 14 is an elastic member having a fixed frame body 141 and an elastic portion 142, and is a layer (elastic layer) forming a spring mechanism. In addition, as a raw material of the 2nd parallel spring 14, SUS type metal material or phosphor bronze etc. are employ | adopted, for example.

  The fixed frame 141 constitutes the outer peripheral portion of the second parallel spring 14 and is joined to the frame 15 f of the adjacent actuator layer 15. Here, the distance between the electrode portions 1551S and 1553S of the actuator layer 15 and the second parallel spring 14 is usually only about 10 μm. For this reason, when the side wiring 21 for supplying voltage and current to the heater layer 154 is simply provided from the imaging element layer 18 to the actuator layer 15 by printing or the like, for example, the side wiring 21 extends to the fixed frame 141. End up. That is, the side wiring 21 and the second parallel spring 14 are short-circuited.

  Therefore, in order to prevent this short circuit, a notch 143 that is recessed at the outer edge near the four corners of the fixed frame 141 of the second parallel spring 14 is provided. The notch 143 is an epoxy system used for joining when the second frame layer 13 and the second parallel spring 14 are joined and when the second parallel spring 14 and the actuator layer 15 are joined. Insulating part 14ep (FIGS. 3 to 5) is formed by filling an adhesive such as resin. Due to the presence of the insulating portion 14ep, unnecessary short circuit due to contact between the side wiring 21 and the second parallel spring 14 is prevented.

  The elastic part 142 has a connection part PG1 with the fixed frame 141 and a joint part PG2 with the lens group 20, and the connection part PG1 and the joint part PG2 are connected by a plate-like member EB. Then, as shown in FIG. 24, the second parallel spring 14 is joined to the lens group 20 at a joint portion PG <b> 2 provided in the elastic portion 142. Here, the first protrusion 201 contacts the free end FT of the actuator layer 15 through the gap between the fixed frame 141 of the second parallel spring 14 and the plate member EB. That is, the second parallel spring 14 has a shape that does not contact the first protrusion 201 of the lens group 20.

  Then, as the lens group 20 is moved in the + Z direction with respect to the fixed frame body 141, the positions of the connecting portion PG1 and the joint portion PG2 in the Z direction shift, and the plate-like member EB undergoes bending deformation (flexure deformation). Bend. That is, the second parallel spring 14 can be elastically deformed in the optical axis direction (± Z direction) of the lens group 20 by elastic deformation of the plate-like member EB, and functions as a spring mechanism.

  The second parallel spring 14 is manufactured using a SUS metal material or phosphor bronze. For example, when the second parallel spring 14 is made of a SUS-based metal material, a resist in the shape of a parallel spring is patterned on the metal material by a photolithography technique, and dipped in an iron chloride-based etching solution to be wet. Etching is performed to form a parallel spring pattern.

<(2-2-6) Second frame layer>
As shown in FIG. 3, the second frame layer 13 is a ring-shaped member in which the outer edge and the inner edge of the XY cross section are each substantially rectangular, and forms a hollow portion that penetrates along the Z axis. The second frame layer 13 surrounds the lens group 20 from the side by arranging the lens group 20 in the hollow portion. In addition, resin, glass, etc. are mentioned as a raw material which comprises the 2nd frame layer 13, The 2nd frame layer 13 is manufactured by what is called a press method using a metal metal mold | die, the injection molding method, etc. The lower end surface (one main surface) located on the −Z side of the second frame layer 13 is joined to the fixed frame body 141 of the adjacent second parallel spring 14. The upper end surface (other main surface) located on the + Z side of the second frame layer 13 is adjacent to the adjacent first parallel spring 12 (specifically, the fixed frame body 121 (FIG. 25) of the first parallel spring 12). Be joined.

<(2-2-7) First parallel spring>
FIG. 25 is an external view of the lower surface of the first parallel spring 12 when the first parallel spring 12 is viewed from below (−Z direction). As shown in FIG. 25, the first parallel spring 12 is an elastic member having the same configuration and function as the second parallel spring 14 except that the notch portion 143 is not provided. 121 and an elastic part 122. One main surface of the fixed frame 121 is joined to the other main surface of the adjacent second frame layer 13, and the other main surface of the fixed frame 121 is connected to the adjacent first frame layer 11 (in detail, the first 1 frame layer 11-lower end surface on the -Z side).

  FIG. 26 is a view showing the first parallel spring 12 joined to the lens group 20. As illustrated in FIG. 26, the joint portion PG <b> 2 provided in the elastic portion 122 is joined to the upper end surface on the + Z side of the protrusion 202 of the lens group 20. For this reason, when the lens group 20 is moved relative to the fixed frame 121 in the + Z direction, elastic deformation occurs in the plate-like member EB, and the first parallel spring 12 functions as a spring mechanism.

<(2-2-8) First frame layer>
As shown in FIG. 3, the first frame layer 11 is a ring-shaped member in which the outer edge and the inner edge of the XY cross section are each substantially rectangular like the second frame layer 13 and penetrates along the Z axis. A hollow part is formed. The hollow portion of the first frame layer 11 becomes a space in which the plate-like member EB and the protruding portion 202 that are elastically deformed when the lens group 20 is moved in the + Z direction can move. The first frame layer 11 is formed by the same material and manufacturing method as the second frame layer 13. The lower end surface (one main surface) located on the −Z side of the first frame layer 11 is joined to the fixed frame body 121 of the adjacent first parallel spring 12. Moreover, the upper end surface (other end surface) located on the + Z side of the first frame layer is joined to the adjacent lid layer 10 (specifically, near the outer peripheral portion of the lid layer). The thickness of the first frame layer 11 along the Z axis ensures a space in which the lens group 20 moves, that is, a movable range (stroke) along the Z axis of the lens group 20. The extension distance along the Z axis of the second protrusion 202 is such that the lens group 20 is pushed up in the + Z direction when the lens position adjusting layer 16 is bonded to the actuator layer 15 and the lens group 20. Is equal to or greater than the total of the distance movable in the + Z direction (movable distance).

<(2-2-9) Lid layer>
As shown in FIG. 3, the lid layer 10 has a substantially square outer edge in the XY cross section, and has a hole (through hole) 10 </ b> H penetrating in a direction parallel to the Z axis at a substantially center, and substantially in the XY plane. It is a plate-like member having a parallel board surface. The through-hole 10H is a hole for guiding light from the subject to the image sensor 181 through the lens group 20, and the lid layer 10 is formed by, for example, a technique of pressing a flat resin material or a resin material. The through-hole 10H is formed by a technique such as etching after patterning.

  In addition, although illustration is abbreviate | omitted in FIG. 3, on the upper surface (other main surface) side of the lid | cover layer 10 so that dust etc. may not penetrate | invade into the camera module 500 from the through-hole 10H of the lid | cover layer 10, A transparent protective layer composed of glass or the like is provided as appropriate.

<(3) Camera module manufacturing process>
Here, a manufacturing process of the camera module 500 will be briefly described. FIG. 27 is a flowchart showing the manufacturing process of the camera module 500. As shown in FIG. 27, (process A) generation of the lens group 20 (step SP1), (process B) sheet preparation (step SP2), (process C) assembly jig preparation (step SP3), (process D) First bonding of the sheet (step SP4), (Process E) Mounting of the lens group 20 (Step SP5), (Process F) Second bonding of the sheet (Step SP6), (Process G) Image sensor substrate 178 (Step SP7) and (process H) dicing (step SP8) are sequentially performed, and the camera module 500 is manufactured.

<(3-1) Generation of Lens Group (Process A)>
In step SP1, the lens group 20 is generated. Here, first, a wafer in which a large number of lens groups 20 are arranged in a matrix (hereinafter also referred to as a “lens group wafer”) is manufactured, and a large number of lens groups 20 are separated into pieces by dicing. Group 20 is produced. The lens group wafer includes a wafer in which a large number of first lens constituent layers LY1 are arranged (first lens constituent layer wafer), a wafer in which a large number of spacer layers RB are arranged (spacer layer wafer), and a large number of second lenses. A wafer (second lens constituent layer wafer) on which the constituent layers LY2 are arranged is laminated and bonded together.

<(3-2) Preparation of sheet (Process B)>
In step SP2, a sheet relating to each functional layer constituting the camera module 500 is formed for each layer. Here, a disc-shaped sheet at the wafer level is prepared. A large number of chips corresponding to members related to the functional layer are formed in a matrix on the sheet for each functional layer. Specifically, in step SP2, the functions such as the lid layer 10, the first frame layer 11, the first parallel spring 12, the second frame layer 13, the second parallel spring 14, the actuator layer 15, and the lens position adjustment layer 16 are performed. Each of the sheets U10 to U16 in which a large number of chips relating to the layers are formed in a predetermined arrangement, and a large number of chips relating to the imaging element substrate 178 formed by joining the cover glass layer 17 and the imaging element layer 18 are formed in a predetermined arrangement. Each sheet (imaging device substrate sheet) U178 is prepared. That is, eight sheets U10 to 16 and U178 are prepared.

  Here, regarding a sheet (actuator layer sheet) U15 in which a large number of chips corresponding to the actuator layer 15 are formed in a matrix in a predetermined arrangement, for example, using a micromachining technique used in a semiconductor manufacturing process, the following is performed. It is manufactured by a simple process. First, an SOI (silicon on insulator) wafer having an active layer having a thickness that matches the design value of the base layer 151 is prepared. Next, a resist film having a desired pattern is formed on the active layer side of the SOI wafer by photolithography. Then, by etching the SOI wafer by reactive ion etching (RIE) of Inductively Coupled Plasma (ICP), a large number of chips of the base layer 151 are formed in a predetermined arrangement in the active layer. A processed wafer (base layer wafer) is formed. Thereafter, formation of a resist film having a desired pattern by photolithography, sputtering (or vapor deposition), removal of the resist film by oxygen plasma ashing, or the like is appropriately performed, so that each base layer 151 is formed on the base layer wafer. The actuator element layer 152, the first insulating layer 153, the heater layer 154, the conductive layer 155, and the second insulating layer 156 are sequentially formed so as to correspond to the above. Finally, after a resist film for surface protection is formed by photolithography, etching of the BOX layer (buried oxide layer) of the SOI wafer is performed with hydrofluoric acid, thereby manufacturing the actuator layer sheet U15. Is completed. Note that the second insulating layer 156 may be formed of a resist film.

<(3-3) Preparation of assembly jig (Process C)>
In step SP3, an assembly jig is prepared. The assembling jig is configured by providing a plurality of protrusions having substantially the same shape on a flat base in a predetermined arrangement. In the assembly jig, alignment marks for alignment are formed at two or more predetermined locations. The upper surface of the protrusion is configured to be substantially parallel to the main surface of the flat base. A unit corresponding to each camera module 500 is manufactured on the upper surface.

<(3-4) Sheet First Joining (Step D)>
In step SP4, three sheets U11 to U13 among the eight prepared sheets U10 to 16 and U178 are joined. Here, the first frame layer sheet U11, the first parallel spring sheet U12, and the second frame layer sheet U13 are aligned in the sheet shape so that the chips included in the sheets U11 to U13 are stacked on each other. (Alignment) is performed. And each sheet | seat U11-U13 is joined using an adhesive agent etc.

  FIG. 28 shows a state in which three sheets U11 to U13 are stacked and joined in step S4, a lens group 20 is attached in step S5, and four sheets U10 and U14 to U16 are stacked in step S6. It is a figure which shows typically a mode that it joins and a mode that the image pick-up element board | substrate sheet | seat U178 is joined by step SP7.

<(3-5) Attaching the lens group (Process E)>
In step SP5, the lens group 20 generated in step SP1 is attached to a hollow portion of each second frame layer 13 of the unit manufactured in step SP4 by a predetermined mounter. That is, the lens group 20 is inserted into each gap of the second frame layer sheet U13 having a lattice shape. Specifically, while the lens group 20 is pressed against the joint PG2, the end surface of the second protrusion 202 is joined to the one main surface side of the joint PG2. In addition, as this joining technique, the technique etc. which join using the adhesive agent (ultraviolet curing adhesive) hardened | cured by irradiation of an ultraviolet-ray are mentioned, for example.

<(3-6) Sheet second joining (process F)>
In step SP6, four sheets U10 and U14 to U16 of the eight sheets U10 to 16 and U178 prepared in step SP2 are joined. Specifically, in step SP6, each chip included in the second parallel spring sheet U14 and the actuator layer sheet U15 is attached to the second frame layer sheet with respect to one main surface side of the units generated up to step SP5. Positioning (alignment) is performed while maintaining the sheet shape so as to be stacked on each chip included in U13. And each sheet | seat U14, U15 is joined using an adhesive agent etc. in order.

  Further, the sheet is so formed that each chip included in the lid layer sheet U10 is stacked with respect to each chip included in the first frame layer sheet U11 with respect to the other main surface side of the first frame layer sheet U11. Alignment (alignment) is performed in the shape. In this state, the lid layer sheet U10 is bonded to the other main surface side of the first frame layer sheet U11 using an adhesive or the like.

  Further, the sheet-like shape is formed so that each chip included in the lens position adjustment layer sheet U16 is stacked on each chip included in the actuator layer sheet U15 with respect to one main surface side of the actuator layer sheet U15. The alignment (alignment) is performed as it is. In this state, the lens position adjustment layer sheet U16 is bonded to one main surface side of the actuator layer sheet U15 using an adhesive or the like.

<(3-7) Mounting of image pickup device substrate (process G)>
In step SP7, the lens is arranged so that the outer peripheral portion of the image sensor substrate 178 is bonded to the frame 161 of the lens position adjustment layer 16 of the unit formed by bonding the lens position adjustment layer 16 by step SP6. The other main surface of the imaging element substrate sheet U178 is joined to one main surface of the position adjustment layer sheet U16.

<(3-8) Dicing (Process H)>
In step SP8, a large number of lens groups 20 are inserted, and a laminated member formed by laminating eight sheets U10 to U16 and U178 is protected by a dicing tape or the like and then separated for each chip by a dicing device. . At this time, the production of a large number of camera modules 500 is completed. In the middle of this dicing process, the side wiring 21 is formed. Specifically, at the time when dicing along one direction is performed, the electrode portions 1551S and 1553S are exposed on the cut surface corresponding to the side surface of each camera module 500. For this reason, the conductive material for forming the side surface wiring 21 is applied to the cut surface, and then dicing along the other direction is performed, whereby the production of a large number of camera modules 500 is completed.

<(4) Lens drive in camera module>
In the camera module 500, as described above, the lens group 20 is pressed against the lens position adjusting layer 16 by the elastic force of the first and second parallel springs 12 and 14 in the non-driven state, and the lens group 20 Is placed in the initial position. At this time, the camera module 500 focuses on a subject located at infinity with the camera module 500 as a reference.

  Then, when the movable portions 15a and 15b of the actuator layer 15 are deformed, the free end FT pushes the first protrusion 201 in the + Z direction. The movable portions 15a and 15b push the lens group 20 in the + Z direction against the elastic force of the first and second parallel springs 12 and 14. At this time, the distance between the lens group 20 and the image sensor 181 is changed, and auto-focus (AF) control capable of focusing on subjects located at various distances with the camera module 500 as a reference is realized. Is done.

  As described above, the force generators 152a and 152b contract and deform due to heating by energization of the heaters 154a and 154b provided in the actuator layer 15. Then, the free ends FT of the movable portions 15a and 15b are displaced in the + Z direction. Note that the amount of displacement generated on the free end FT side of the movable portions 15a and 15b varies depending on the heating temperature of the SMA, and the amount of displacement is adjusted by controlling the amount of current supplied to the heater portions 154a and 154b. Here, since the electrical resistance of the heater portions 154a and 154b also changes according to the deformation of the heater portions 154a and 154b accompanying the deformation of the SMA, the electrical resistance of the heater portions 154a and 154b is monitored and the free end FT , That is, the displacement amount of the lens group 20 can be controlled.

  As described above, in the mobile phone 100 equipped with the camera module 500 according to the embodiment of the present invention, the electrode unit 1551S and the heater unit 154a have a lower electrical resistance per unit length than the heater unit 154a. Electrical connection is made by the conductive portion 1551. With such a configuration, when the lens group 20 is moved, heat generation is suppressed in the wiring that electrically connects the electrode portion 1551S and the heater portion 154a, so that power consumption can be reduced due to an increase in thermal efficiency.

  Further, the electrode portion 1553S and the heater portion 154b are electrically connected by a third conductive portion 1553 having a lower electrical resistance per unit length than the heater portion 154b. With such a configuration, when the lens group 20 is moved, heat generation is suppressed in the wiring that electrically connects the electrode portion 1553S and the heater portion 154b, so that power consumption can be reduced due to an increase in thermal efficiency.

  Further, the heater unit 154a and the heater unit 154b are electrically connected by a second conductive unit 1552 having a lower electrical resistance per unit length than the heater units 154a and 154b. With such a configuration, when the lens group 20 is moved, heat generation is suppressed in the wiring that electrically connects the heater unit 154a and the heater unit 154b, so that power consumption can be reduced due to an increase in thermal efficiency.

<(5) Modification>
It should be noted that the present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the gist of the present invention.

  For example, in the above embodiment, in order to make the electrical resistance per unit length of the first to third conductive parts 1551 to 1553 lower than the electrical resistance per unit length of the heater parts 154a and 154b, the heater part The first to third conductive parts 1551 to 1553 are formed using a material having a lower resistivity than the material constituting the 154a and 154b, and the first to third conductive parts 1551 to 1553 are thicker than the heater parts 154a and 154b. However, it is not limited to this. For example, by adjusting at least one of the structure such as thickness, thickness, cross-sectional area, and the resistivity, the electric resistance per unit length of the first to third conductive portions 1551 to 1553 can be changed to the heater portions 154a and 154b. The electrical resistance per unit length may be lower.

  In the above-described embodiment, in the actuator layer 15, the first conductive portion 1551 that electrically connects the electrode portion 1551S and the heater portion 154a, and the second that electrically connects the heater portion 154a and the heater portion 154b. Although the conductive portion 1552 and the third conductive portion 1553 that electrically connects the electrode portion 1553S and the heater portion 154b are provided in layers, the present invention is not limited thereto. For example, the actuator layer 15 is not provided with the conductive layer 155 and the second insulating layer 156, and a conductive frame (conductive frame layer) having the same function as that of the conductive layer 155 is used as the actuator layer 15 and the second parallel spring 14. You may make it provide between. Here, a mobile phone 100A equipped with a camera module 500A, which is a specific example of such a configuration, will be described.

  FIG. 29 is a schematic cross-sectional view of a camera module 500A according to a modification. As shown in FIG. 29, the camera module 500A changes the actuator layer 15 to an actuator layer 15A from which the conductive layer 155 and the second insulating layer 156 are removed, as compared with the camera module 500 according to the embodiment. In addition, a frame-like layer (conductive frame layer) 19A configured using a conductive material is provided between the actuator layer 15A and the second parallel spring 14. And here, between the electrode portion 1551S and the heater portion 154a, between the heater portion 154a and the heater portion 154b, and by the conductive frame layer 19A having a lower electrical resistance per unit length than the heater portions 154a and 154b, and The electrode portion 1553S and the heater portion 154b are electrically connected to each other.

  FIG. 30 is a top view of the conductive frame layer 19A when the conductive frame layer 19A as a conductive layer is viewed from above (+ Z side). As shown in FIG. 30, the conductive frame layer 19A includes a first conductive portion 191 that electrically connects the electrode portion 191S and the heater portion 154a, and a second portion that electrically connects the heater portion 154a and the heater portion 154b. The electroconductive part 192 and the 3rd electroconductive part 193 which electrically connects the electrode part 193S and the heater part 154b are provided. The first to third conductive parts 191 to 193 are provided in this order and are separated from each other. Between the first conductive part 191 and the second conductive part 192, between the second conductive part 192 and the third conductive part 193, and between the third conductive part 193 and the first conductive part 191, The adhesive is filled when the adjacent second parallel spring sheet U14 and the sheet (conductive frame layer sheet) on which the conductive frame layer 19A is arranged are joined. Thereby, a short circuit occurs between the first conductive part 191 and the second conductive part 192, between the second conductive part 192 and the third conductive part 193, and between the third conductive part 193 and the first conductive part 191. do not do. Further, for example, the other main surface of the conductive frame layer 19A (on the + Z side) so as not to short-circuit between the second parallel spring 14 and the conductive frame layer 19A and between the second conductive portion 192 and the side surface wiring 21. ) And the end surface on the −X side of the second conductive portion 192, an oxide insulating film is formed respectively. In addition, about a conductive frame layer sheet | seat, it manufactures, for example by giving a metal press process etc. with respect to a copper disk-shaped board.

  In the above embodiment, the force generators 152a and 152b are made of a shape memory alloy, but the present invention is not limited to this. For example, the force generators 152a and 152b may be made of a material having a thermal expansion coefficient higher than that of the material forming the base layer 151 instead of the shape memory alloy. More specifically, the base layer 151 is formed of a material having a relatively small thermal expansion coefficient such as silicon, and the force generating portions 152a and 152b are formed of a material having a relatively large thermal expansion coefficient such as aluminum or nickel. (Bi-metallic strip) may be applied.

  In such a configuration, deformation such that the movable portions 15a and 15b warp due to a difference in expansion between the projecting portions 151a and 151b and the force generating portions 152a and 152b according to the heat generation of the heater portions 154a and 154b. As a result, a displacement of the free end FT occurs. However, in order to displace the free end FT upward (+ Z direction), it is necessary to reverse the stacking order of the plurality of layers constituting the movable parts 15a and 15b according to the above-described embodiment. In the configuration in which such a bimetal is applied, the force generators 152a and 152b can be formed using a material that is less expensive than when a shape memory alloy is used. For this reason, the manufacturing cost of the actuator layer 15 can be reduced.

  In the above embodiment, the actuator layer 15 is provided with the two movable parts 15a and 15b. However, the present invention is not limited to this. For example, the actuator layer 15 may be provided with one movable part. Three or more movable parts may be provided. Here, a configuration example of the actuator layer 15A in which the movable portion 15b is removed from the actuator layer 15 will be described.

  FIG. 31 is a top view of the actuator layer 15A when the actuator layer 15A is viewed from above (+ Z side). 32 to 37 are diagrams showing the configuration of each layer constituting the actuator layer 15A. In FIGS. 31 to 37, the same reference numerals are given to the same parts of the configuration of the actuator layer 15A as those of the actuator layer 15 according to the above-described embodiment shown in FIGS. Here, redundant description is omitted.

  The actuator layer 15A includes a base layer 151A (FIG. 32), an actuator element layer 152A (FIG. 33), a first insulating layer 153A (FIG. 34), a heater layer 154A (FIG. 35), a conductive layer 155A (FIG. 36), and a first layer. Two insulating layers 156A (FIG. 37) are stacked in this order from the −Z side to the + Z side.

  The actuator layer 15A shown in FIG. 31 is different from the actuator layer 15 shown in FIG. 13 in that the frame body 15f constituting the outer peripheral portion is different from the frame body 15fA having different configurations related to the heater layer 154A and the conductive layer 155A. While being changed, the movable portion 15b is removed. The base layer 151A shown in FIG. 32 has a configuration in which the protruding portion 151b is removed as compared with the base layer 151 shown in FIG. The actuator element layer 152A illustrated in FIG. 33 has a configuration in which the force generation unit 152b is removed as compared to the actuator element layer 152 illustrated in FIG. The first insulating layer 153A shown in FIG. 34 has a configuration in which a portion corresponding to the movable portion 15b is removed as compared with the first insulating layer 153 shown in FIG. The second insulating layer 156A shown in FIG. 37 has a configuration in which a portion corresponding to the movable portion 15b is removed, compared to the second insulating layer 156 shown in FIG.

  The heater layer 154A shown in FIG. 35 is provided in a shape like one elongated wiring, like the heater layer 154 shown in FIG. Specifically, in the heater layer 154A, the wiring portion 1541A, the heater portion 154a, and the wiring portion 1542A are extended in this order, and are sequentially electrically connected. The wiring portions 1541A and 1542A constitute the frame body 15fA, and the heater portion 154a constitutes the movable portion 15a. Note that one end of the wiring portion 1541A is electrically connected to one end portion on the −X side of the heater portion 154a, and the wiring portion 1541A extends in the −X direction. In addition, one end of the wiring portion 1542A is electrically connected to the other end on the −X side of the heater portion 154a, and the wiring portion 1542A extends in the −X direction.

  The conductive layer 155A shown in FIG. 36 is made of a conductor having a relatively lower resistivity than the material forming the heater layer 154A, such as copper, like the conductive layer 155 shown in FIG. The conductive layer 155A is formed by a first conductive portion 1551A that covers the main surface (other main surface) on the + Z side of the wiring portion 1541A, and a second conductive portion 1552A that covers the main surface (other main surface) on the + Z side of the wiring portion 1542A. Composed. That is, substantially the entire area excluding the heater portion 154a in the main surface (other main surface) on the + Z side of the heater layer 154A is covered with the conductive layer 155A. And 1st and 2nd electroconductive part 1551A, 1552A is provided separately, respectively, and comprises frame 15fA. Further, the widths of the first and second conductive portions 1551A and 1552A are both about the same as the width of the frame 15fA, and the widths of the first and second conductive portions 1551A and 1552A are compared with the thickness of the heater layer 154A. The thickness is relatively thick.

  The first conductive portion 1551A is provided from the vicinity of the inner edge of the frame 15f to the outer edge, covers the main surface (other main surface) on the + Z side of the wiring portion 1541A, and one end portion of the first conductive portion 1551A is the heater portion 154a. Is electrically connected to one end of the. The other end portion of the first conductive portion 1551A that forms the outer edge of the frame 15fA forms an electrode portion 1551SA that is electrically connected to the side surface wiring 21. That is, the first conductive portion 1551A functions as a conductive portion that electrically connects the electrode portion 1551SA to which the side wiring 21 is electrically connected and one end portion of the heater portion 154a.

  The second conductive portion 1552A covers substantially the entire area of the main surface (other main surface) on the + Z side of the wiring portion 1542A, and one end portion of the second conductive portion 1552A is electrically connected to the other end portion of the heater portion 154a. Is done. The other end portion of the second conductive portion 1552A that forms the outer edge of the frame 15fA forms an electrode portion 1552SA that is electrically connected to the side wiring 21. That is, the second conductive portion 1552A functions as a conductive portion that electrically connects the electrode portion 1552SA to which the side wiring 21 is electrically connected and the other end of the heater portion 154a.

  With such a configuration of the actuator layer 15A, the heater layer 154A and the conductive layer 155A form a wiring through which a current flows between the electrode portion 1551SA and the electrode portion 1552SA. In this wiring, the electric resistance of the first and second conductive portions 1551A and 1552A is relatively lower than the electric resistance of the heater portion 154a. Specifically, assuming that the direction in which current flows in the wiring electrically connecting the electrode portion 1551SA and the electrode portion 1552SA is the extending direction of the wiring, the unit in the extending direction of the first and second conductive portions 1551A, 1552A. The electrical resistance per length is relatively lower than the electrical resistance per unit length in the extending direction of the heater portion 154a. Therefore, when a voltage is applied between the electrode portion 1551SA and the electrode portion 1552SA and a current flows through the wiring formed of the heater layer 154A and the conductive layer 155A, the electric resistance is relatively higher than that of other portions. The heater unit 154a generates heat due to its own Joule heat. That is, the heater unit 154a as the heat generating unit generates heat in response to the supply of current. On the other hand, in the wiring composed of the heater layer 154A and the conductive layer 155A, the portion excluding the heater portion 154a has a lower electrical resistance than the heater portion 154a, so that heat generation due to current supply is suppressed. The deformation of the movable portion 15a due to the heat generated by the heater portion 154a and the movement of the lens group 20 due to the deformation are the same as those in the above embodiment.

  In the above embodiment, the movable parts 15a and 15b have a so-called cantilever structure in which one end is fixed to the frame 15f. However, the present invention is not limited to this. For example, what has what is called a doubly-supported beam structure in which both ends of the movable part are fixed to the frame is also conceivable.

  In the above embodiment, the heater units 154a and 154b are connected in series. However, the present invention is not limited to this, and a current and a voltage may be separately supplied to the heater units 154a and 154b. .

  In the above embodiment, the conductive layer 155 is provided on the surface (other main surface) on the + Z side of the heater layer 154. However, the present invention is not limited to this. For example, the order in which the heater layer 154 and the conductive layer 155 are stacked may be reversed.

  In the above-described embodiment, each of the movable portions 15a and 15b includes the projecting portions 151a and 151b, the force generating portions 152a and 152b, the first insulating layer 153, the heater portions 154a and 154b, and the second insulating layer 156. Although it is configured to be overlapped, it is not limited to this. For example, each movable part 15a, 15b is provided with a protruding part 151a, 151b, a force generating part 152a, 152b, and the like, such as disposing an insulating layer between the protruding parts 151a, 151b and the force generating parts 152a, 152b. It is only necessary to have a structure in which a plurality of layers including the heater portions 154a and 154b are stacked. In the above-described embodiment, the projecting portions 151a and 151b, the force generating portions 152a and 152b, and the heater portions 154a and 154b each have a layered shape. However, the present invention is not limited to this. For example, in each of the movable parts 15a and 15b, a structure having a certain thickness is adopted for the heater parts 154a and 154b, and a plurality of parts including the projecting parts 151a and 151b, the force generating parts 152a and 152b, and the heater parts 154a and 154b are used. A structure in which the portions are stacked may be employed.

  In the above embodiment, the heater portions 154a and 154b constitute the movable portions 15a and 15b. However, the present invention is not limited to this. For example, the heater parts 154a and 154b may constitute not only the movable parts 15a and 15b but also a part of the frame 15f. Moreover, in the said one Embodiment, although the conductive layer 155 comprised the frame 15f, it is not restricted to this. For example, the conductive layer 155 may constitute not only the frame 15f but also a part of the movable portions 15a and 15b.

  In the above embodiment, the camera module 500 is mounted on the mobile phone 100. However, a configuration similar to the camera module 500 may be mounted on a compact digital camera.

  In the above embodiment, the object moved by the movable parts 15a and 15b (moving object) is the lens group 20 as an optical system, but is not limited thereto. For example, other members such as an image sensor may be used as the moving object. For example, the lens group 20B corresponding to the optical system that guides light from the subject to the image sensor is fixed, and the image sensor layer is arranged in the direction along the Z-axis by a configuration similar to the configuration for moving the lens group 20 in the one embodiment. It may be moved to.

  FIG. 38 is a diagram illustrating a conceptual diagram of an aspect in which the lens group 20B is fixed and the imaging element layer 18B is moved back and forth in a direction along the optical axis Ax of the lens group 20B. In FIG. 38, an imaging unit PBB that moves the imaging element layer 18B back and forth along the optical axis Ax is depicted. In such a configuration, the image pickup element layer 18B is moved back and forth along the optical axis Ax according to the operation of the actuator layer, and the distance between the lens group 20B and the image pickup element layer 18B is changed. Control is realized. As described above, when at least one of the image sensor and the optical system is moved according to the bending deformation of the movable portions 15a and 15b, the autofocus control is realized.

  Moreover, the target object (moving target object) moved by the actuator is not limited to an element constituting the imaging apparatus such as an optical system or an imaging element. For example, the moving object may be another object such as an objective lens of an optical pickup lens. That is, the present invention can be applied to an actuator and a drive device in which a moving object is moved according to bending deformation of the actuator.

  It goes without saying that all or a part of each of the above-described embodiment and various modifications can be appropriately combined within a consistent range.

15, 15A Actuator layer 15a, 15b Movable part 15f, 15fA Frame 18, 18B Imaging element layer 19A Conductive frame layer 20, 20B Lens group 100, 100A Mobile phone 151, 151A Base layer 151a, 151b Protruding part 151f Base frame 152, 152A Actuator element layer 152a, 152b Force generation part 153, 153A First insulation layer 154, 154A Heater layer 154a, 154b Heater part 155, 155A Conductive layer 156, 156A Second insulation layer 181 Imaging element 191 First conductive part 192 Second conductive portion 193 Third conductive portion 500, 500A Camera module 1551, 1551A First conductive portion 1551S, 1551SA, 1552SA, 1553S Electrode portion 1552, 1552A Second conductive portion 1553 Third conductive portion P B, PBB imaging unit

Claims (7)

A fixed part;
A plurality of portions including a first beam portion provided for the fixed portion, a first force generating portion that generates a force in response to heating, and a first heat generating portion that generates heat in response to a current supply are stacked. And a first movable portion that is deformed in response to heat generated in the first heat generating portion,
A plurality of portions including a second beam portion provided for the fixed portion, a second force generating portion that generates a force in response to heating, and a second heat generating portion that generates heat in response to a current supply are stacked. A second movable portion that is configured and deforms in response to heat generated in the second heat generating portion;
A conductive portion that electrically connects the first heat generating portion and the second heat generating portion and has a lower electrical resistance per unit length than the first and second heat generating portions;
An actuator comprising: The actuator according to claim 1,
The first and second force generators are
An actuator comprising a shape memory alloy. The actuator according to claim 1,
The first and second force generators are
An actuator having a thermal expansion coefficient higher than that of the first and second beam portions. The actuator according to any one of claims 1 to 3, and
A moving object moved by deformation of the first and second movable parts;
A drive device comprising: The actuator according to any one of claims 1 to 3, and
An image sensor;
An optical system for guiding light from a subject to the image sensor;
With
At least one of the image sensor and the optical system is moved by deformation of the first and second movable parts. A fixed part;
A plurality of portions including a first beam portion provided for the fixed portion, a first force generating portion that generates a force in response to heating, and a first heat generating portion that generates heat in response to a current supply are stacked. A first movable part configured and deformed in response to heat generated in the first heat generating part,
A plurality of portions including a second beam portion provided for the fixing portion, a second force generating portion that generates a force in response to heating, and a second heat generating portion that generates heat in response to a current supply are stacked. A second movable part configured to be deformed in response to heat generated in the second heat generating part,
An actuator layer comprising:
A conductive layer that electrically connects the first heat generating portion and the second heat generating portion and has a lower electrical resistance per unit length than the first and second heat generating portions;
A moving object moved by the first and second movable parts;
A drive device comprising: A drive device according to claim 6,
An image sensor, and an optical system that guides light from a subject to the image sensor,
The moving object is
An imaging apparatus comprising at least one of the imaging element and the optical system.

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