JP2011145324A - Imaging device and portable equipment having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent peeling of an adhesive from a supporting member or a lens holder due to difference in thermal expansion between a supporting member and a lens holder, and to prevent reduction in positional accuracy of a lens and an imaging element and reduction in resolution. <P>SOLUTION: An imaging device includes a lens 2, a lens holder 3 for storing the lens 2, a frame 5 having a cylindrical outer holder 4 for storing the lens 2 via the lens holder 3, the imaging element 7 having the lens 2 at a position of a predetermined distance and a light receiving section in its center, the supporting member 6 that is attached to the upper part on a subject side of the outer holder 4 and frame 5 and elastically supports the outer holder 4 in the optical axis direction, and an actuator 12 for operating the lens holder 3 and outer holder 4 back and forth. The thermal expansion coefficient of the supporting member 6 is set to be larger than that of the outer holder 4, and at least the supporting member 6 and lens holder 3 are fixed by the adhesive 11. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging device used for a digital camera, a mobile phone, and the like.

  In recent years, an imaging apparatus having an autofocus (AF) function uses an SMA (wire made of a shape memory alloy) as an actuator from the viewpoint of high-speed movement and miniaturization (see Patent Document 1). In this SMA, a current is passed and controlled at a temperature of, for example, about 120 ° C., and considering the temperature, the material for holding the SMA or the material of the outer holder in the vicinity thereof generally has a high heat melting temperature ( The material is selected. In addition, the material of the lens holder that houses the lens is the same as that of the lens in order to prevent the positional accuracy of the optical center from being lowered due to changes in the temperature environment. Therefore, the materials of the lens and the lens holder and the outer holder may be different. Further, the thermal expansion coefficient of the support member attached to the upper part of the outer holder on the subject side and elastically supporting the outer holder in the optical axis direction is substantially the same as the thermal expansion coefficient of the outer holder.

  The outer holder and the lens holder are generally fixed by rotating the lens holder with respect to the outer holder (lens barrel component) to align the lens focal point with the light receiving portion of the image sensor, and then attaching the outer holder and the lens holder. It is fixed with an adhesive (see Patent Document 2).

Special table 2009-531729 gazette JP 2009-86465 A

  However, in the configuration such as the imaging device, the outer holder and the lens holder are bonded and fixed with materials having different coefficients of thermal expansion, so that the temperature changes in a case where the adhesive is dried at a high temperature or in a use environment in order to shorten the manufacturing time. In this case, due to the difference in thermal expansion between the outer holder and the lens holder, the diameter of the joint portion between the outer holder and the lens holder changes, for example, when the gap between the joint portions becomes large, the tensile stress is applied to the adhesive interposed in the joint portion. The adhesive itself breaks or deforms, or the adhesive peels off from the outer holder or the lens holder, the lens holder rotates relative to the outer holder, and the position accuracy of the lens and the image sensor is increased. There was a problem that the resolution deteriorated and the resolution decreased.

  In the imaging device according to claim 1 of the present invention, a lens, a lens holder that accommodates the lens, a frame that includes a cylindrical outer holder that accommodates the lens via the lens holder, An image sensor provided with a light receiving portion at a central position, a support member attached to the upper part of the outer holder and the subject side of the frame, and elastically supporting the outer holder in an optical axis direction; An actuator for operating the lens holder and the outer holder in the optical axis direction, the thermal expansion coefficient of the support member is larger than the thermal expansion coefficient of the outer holder, and at least the support member and the lens holder are adhesives It is characterized by being fixed with.

  In this case, by making the thermal expansion coefficient of the support member larger than the thermal expansion coefficient of the outer holder, the thermal expansion coefficient of the support member approaches the thermal expansion coefficient of the lens holder. The adhesive is difficult to peel off.

  That is, when the temperature changes depending on the use environment, when the lens holder expands and contracts, the support member also expands and contracts, and it becomes difficult for the lens holder and the support member to be relatively separated from each other. As a result, peeling of the adhesive can be suppressed. Further, even if the adhesive intervenes between the lens holder and the outer holder, the peeling of the adhesive between the support member and the lens holder can be suppressed. Therefore, it is possible to provide a highly accurate and highly safe imaging apparatus that can prevent deterioration in positional accuracy between the lens and the imaging element and a decrease in resolution.

  In the image pickup apparatus according to claim 2 of the present invention, the support member is configured to be deformed in a direction in which the lens holder expands and contracts when the support member is bonded to the lens holder by the adhesive. .

  In this case, the stress of the bonded portion caused by the expansion and contraction of the lens holder due to the temperature change due to energization is absorbed and suppressed by the support member having a shape that deforms according to the direction in which the lens holder expands and contracts.

  In the imaging device according to claim 3 of the present invention, the adhesive is an elastic adhesive.

  In this case, it is possible to absorb the stress of the bonded portion caused by the expansion and contraction of the lens holder due to a temperature change caused by energization with the elastic adhesive.

  A portable device according to a fourth aspect of the present invention is characterized by using the imaging device according to any one of the first to fourth aspects.

  According to the present invention, the thermal expansion coefficient of the support member attached to the upper part of the outer holder and the frame on the subject side is made larger than the thermal expansion coefficient of the outer holder, and at least the support member and the lens holder are fixed with the adhesive. Since it did in this way, while being able to prevent peeling of an adhesive agent, the deterioration of the positional accuracy of a lens and an image pick-up element, and the fall of the resolution can be prevented.

1 is a schematic side sectional view of an imaging apparatus according to a first embodiment of the present invention. Plan view of FIG. The top view of the imaging device concerning a 2nd embodiment of the present invention. Schematic side sectional view showing a modification of the imaging device according to the embodiment of the present invention (A) is the figure which showed the portable apparatus H in which an imaging device is installed, (b) is the figure which showed the imaging device installation part of the portable apparatus

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
First, an imaging apparatus according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the imaging device 1 includes a lens 2, a lens holder 3 that accommodates the lens 2, and a frame 5 that includes a cylindrical outer holder 4 that accommodates the lens 2 via the lens holder 3. A leaf spring 6 as a support member, which is attached to the upper part of the outer holder 4 on the subject side and elastically supports the outer holder 4 in the optical axis direction, and is arranged at a predetermined distance from the lens 2 and at the center thereof It is mainly composed of an image sensor 7 having a light receiving portion, a substrate 8 on which the image sensor 7 is mounted, a transparent plate 9 covering the image sensor 7, and an infrared cut filter 10.

The lens holder 3 accommodates a plurality (three in FIG. 1) of lenses 2. An opening 3 a is provided in the upper part of the lens holder 3. The opening 3 a functions as a diaphragm of the lens 2. A male screw 3 b is formed on the outer surface of the lens holder 3. The lens 2 and the lens holder 3 are made of a material having a thermal expansion coefficient (linear expansion coefficient) that is close or substantially the same, such as a polycarbonate having a linear expansion coefficient of about 6.6 × 10 ⁻⁵ / ° C. ZEONEX manufactured by Nippon Zeon Co., Ltd. having a linear expansion coefficient of about 7 × 10 ⁻⁵ / ° C. is used.

The outer holder 4 has a substantially cylindrical outer shape, and has an internal thread 4a formed on the inner surface thereof. The male screw 3b of the lens holder 3 is screwed into the female screw 4a, and the lens 2, the lens holder 3, the outer holder 4 and the frame 5 are arranged concentrically. Further, as the material of the outer holder 4 and the frame 5, since SMA is used as an actuator 13 described later, a material higher than the heat melting temperature of the lens holder 3, for example, a liquid crystal polymer having a deflection temperature under load of 235 (° C.) (linear expansion coefficient) Is about 1.3 × 10 ⁻⁵ / ° C.). Since the material of the outer holder 4 and the frame 5 is set to be higher than the heat melting temperature and the coefficient of thermal expansion is smaller than the lens holder 3, driving means that is heated to the outer peripheral side of the outer holder 4 and the frame 5, That is, it is possible to provide an actuator 13 made of a shape memory alloy that thermally contracts when energized.

Then, on the upper surface of the outer holder 4 (surface on the subject side), a positioning for positioning the leaf spring 6 on the extended line of two orthogonal lines passing through the center of the opening 6a when viewed in plan. Four shafts 4b are protruded (see FIG. 2).
Although not shown in detail, the outer shape of the frame 5 has a substantially rectangular parallelepiped shape, and when viewed in plan, a circular cavity is formed at the center. A guide hole 5b is formed in one of the four corners of the pair of adjacent side walls of the frame 5 so that the guide shaft 4c protruding outward from the outer peripheral surface of the outer holder 4 on the imaging device 7 side is inserted. Has been. That is, the guide hole 5b is formed with a long hole in the moving direction (optical axis direction) of the guide shaft 4c.

  Then, the distal end portion of the guide shaft 4c loosely inserted into the guide hole 5b protrudes to the outside, a compression spring (not shown) is externally inserted into the distal end portion, and the outer holder 4 is constantly urged downward by the compression spring, so that the lens 2 It is configured such that the forward / backward movement (movement in the optical axis direction) can be performed quickly, that is, the focus adjustment can be performed quickly. In FIG. 1, the positioning shaft 4b is omitted.

The leaf spring 6 is disposed across the upper surface opening 5 a of the frame 5 and the upper surface opening 4 d of the outer holder 4, and fixes the frame 5 and the outer holder 4. In FIG. 1, the leaf spring 6 is disposed only at the above-mentioned location, but is actually configured as a pair of upper and lower sides, and is parallel to sandwich the lens holder 3 and the outer holder 4 from above and below. Has been placed. Due to the elasticity of the pair of leaf springs 6, the lens 2 is always located at the reference position. As a material of the leaf spring 6, SUS304 (linear expansion coefficient is about 1.73 × 10 ⁻⁵ / ° C.) is used.
As shown in FIG. 2, the leaf spring 6 has a quadrangular shape in plan view, and an opening 6 a having an inner diameter larger than the outer diameter of the lens holder 3 is formed at the center so that the lens holder 3 can advance and retreat. Is formed. Further, a positioning hole 6b into which the distal end portion of the positioning shaft 4b of the outer holder 4 is inserted is formed on an extension of two orthogonal lines passing through the center of the opening 6a when viewed in plan. Further, arc slits 6c extending to both sides around each positioning hole 6b are formed. The arc slit 6c has a length corresponding to the outer circumference of the semicircle of the opening 6a of the leaf spring 6, and the leaf spring 6 so that one side and the other side are alternately located inside and outside. Four are formed on the outer periphery of the opening 6a. A spring portion is formed by each arc slit 6c, and the periphery of the opening 6a of the leaf spring 6 is elastically supported uniformly.

  Further, the leaf spring 6 on the one subject side has the adhesive 11 spread over the periphery of the opening 6a and the annular upper surface of the lens holder 3 and at equal intervals in the circumferential direction (120 degree intervals). It has been applied. Further, the thermal expansion coefficient of the leaf spring 6 is set larger than the thermal expansion coefficient of the outer holder 4. By doing so, the thermal expansion coefficient of the leaf spring 6 approaches the thermal expansion coefficient of the lens holder 3, and peeling of the adhesive 11 between the leaf spring 6 and the lens holder 3 is prevented. Note that even if the adhesive 11 intervenes between the lens holder 3 and the outer holder 4, it is possible to prevent the adhesive 11 from peeling between the leaf spring 6 and the lens holder 3. It is possible to prevent the deterioration of the position accuracy and the resolution.

  The infrared cut filter 10 is provided at a position between the lens 2 and the transparent plate 9. Specifically, the infrared cut filter 10 is fixed to a base 14 provided on the outer holder 4 side. More specifically, the infrared cut filter 10 is fixed to the base 14 at a position inside the positioning portion 15 of the base 14.

  An SMA (a wire made of a shape memory alloy) 12 is disposed along a pair of adjacent side walls of the frame 5 as an actuator for moving the lens holder 3 and the outer holder 4 so as to be able to advance and retract. The SMA 12 is heated by Joule heat by being supplied with current (or electric power) from the pair of conductive terminals 13 and contracts in the length direction, and the lens 2 moves (increases) by this contraction. ). On the other hand, when the current supply from the conductive terminal 13 is stopped, the SMA 12 expands in the length direction (returns to the original shape), and the lens 2 returns from the moved position to the original position. Yes.

  As the adhesive 11, a silicon-based adhesive is used, and the elastic adhesive is adapted to absorb the stress of the adhesive portion caused by the expansion and contraction of the lens holder 3 due to the temperature change caused by the use environment.

  In FIG. 1, the SMA 12 is supported in the vertical direction by one conductive terminal 13 for the sake of convenience, but in reality, the upper end of a holding member (not shown) disposed on the diagonal of the frame 5 described later. Both end portions are fixed to each other, and the outer surface of the side wall of the frame 5 is disposed obliquely downward from both end portions, and the central portion is formed in a groove (not shown) formed in the base end portion of the guide shaft 4c described above. It is caught without looseness. In other words, the SMA 12 is contracted in the length direction when a current is supplied in a state in which tension is applied, and both ends are in a high position and are in a lower position toward the center. That is, at the same time as the SMA 12 contracts in the length direction, the guide shaft 4c is pulled up (moved toward the subject), and the outer holder 4 and the lens holder 3 are pulled up via the guide shaft 4c. In other words, the lens 2 moves along the optical axis direction by contracting in the length direction of the SMA 12.

  One conductive terminal 13 (the member on the right side when FIG. 1 is viewed from the front) is, as shown in FIG. 1, a lower end portion fixed between the frame 5 and the base 14 and then bent upward. The figure is shown as being folded horizontally. The other conductive terminal (member on the left side when FIG. 1 is viewed from the front) 13 is shown only in an end portion fixed between the frame 5 and the base 14. However, each conductive terminal 13 is actually provided at the diagonal position of the frame 5 and along the height direction of the frame 5, and the conductive holding member (not shown) described above, And a conductive power supply member electrically connected to the holding member and electrically connected to an external terminal (not shown). In the present embodiment, this power supply member is referred to as a conductive terminal 13 for convenience.

  The frame 5 has a base 14 that supports the outer holder 4. The base 14 is held at the lower part of the outer holder 4, and is positioned toward the imaging element 7 (or the substrate 8) (downward) and the positioning unit 15 for positioning the lens holder 3 and the lens 2 mainly in the vertical direction. ) And protruding protrusion 16.

  The positioning part 15 is formed in a planar shape having a predetermined area. In addition, the outer periphery of the positioning portion 15 is configured in a square shape in plan view. The positioning unit 15 positions the lens 2 with respect to the image sensor 7 in the vicinity of the outer peripheral portion rather than the light receiving unit of the image sensor 7. Specifically, the positioning unit 15 comes into contact with the surface (upper surface) of the transparent plate 9 located above the image sensor 7. The positioning portion 15 is fixed to the transparent plate 9.

  The protruding portion 16 is configured to protrude toward the substrate 8 at an outer position on the outer peripheral edge of the image sensor 7. In addition, the lower surface of the protrusion 16 is formed in a quadrangular shape (square tube shape) so as to cover the outer periphery of the image sensor 7. Specifically, the protrusion 16 is configured to protrude toward the substrate 8 at an outer position of the outer peripheral edge of the transparent plate 9. Moreover, the lower surface of the protrusion 16 is formed in a quadrangular shape (square tube shape) so as to cover the outer periphery of the transparent plate 9.

The image sensor 5 is fixed on the lower surface side of the transparent plate 9. The lower surface of the transparent plate 9 is fixed to the substrate 8 via a connection portion 17 by other connection means such as a solder bump.
In order to prevent dust from entering the image sensor 7 from the outside, and to protect the image sensor 7 and the transparent plate 9 and the like, although not shown, the space between the protrusion 16 and the substrate 8 is embedded with an adhesive or the like. A sealed structure may be used.

  Hereinafter, a method for manufacturing the imaging device 1 according to the present invention will be described.

  First, the lens 2 is mounted in the lens holder 3, and the male screw 3 b of the lens holder 3 is screwed into the female screw 4 a of the outer holder 4 of the frame 5 to accommodate the lens holder 3 in the outer holder 4.

  Next, the positioning portion 15 provided on the outer holder 4 side is placed at a predetermined position on the transparent plate 9, and the protrusion 16 provided on the outer holder 4 side is placed on the substrate 8. At this time, positioning is performed so that the center of the lens 2 is not positioned relative to the image sensor 7 and the center axis of the lens 2 is not inclined. When this positioning is completed, the outer holder 4 is fixed to the image sensor 7 and the substrate 8. In addition, the space between the protrusion 16 and the substrate 8 may be embedded with an adhesive or the like to form a sealed structure.

Then, the leaf spring 6 is fixedly positioned on the positioning shaft 4 b of the outer holder 4, and the adhesive 11 is applied so as to relate to the lens holder 3, the outer holder 4, and the leaf spring 6. 1 is completed.
(Second Embodiment)
Next, an imaging apparatus according to the second embodiment will be described with reference to FIG. In FIG. 3, the same reference numerals as those in FIG. 2 denote the same or corresponding parts. The difference from the first embodiment is that the opening 6a of the leaf spring 6 and the four outer peripheral portions of the opening 6a are formed. An arc slit 6d shorter than the arc slit 6c is formed in a region between the arc slits 6c, and the lens holder 3 and the outer holder 4 are fixed with an adhesive 11 applied in one place. is there.

  Specifically, between the positioning holes 6b of the leaf spring 6, four second slits shorter than the four arc slits (hereinafter referred to as first arc slits) 6c described above are formed on the extension of the orthogonal center line. A circular slit 6d is formed, and a connecting slit 6e that connects each second circular slit 6d and the opening 6a along the radial direction is formed. By this connection slit 6e, the stress of the adhesion part due to expansion and contraction of the material of the lens holder 3 and the leaf spring 6 can be suppressed by mechanical deformation of the leaf spring 6.

  The imaging apparatus according to the present invention is not limited to the above embodiments, and various modifications can be made.

  For example, in the first and second embodiments described above, the SMA 12 and the pair of conductive terminals 13 are arranged along the outer surface of the side wall of the outer holder 4, but as shown in FIG. 4, the frame 5 and the outer holder 4 It may be arranged in the gap.

In addition, as the adhesive used in each of the above-described embodiments, it is preferable to use a silicon-based elastic adhesive, and the stress of the adhesive portion due to expansion and contraction of the material of the lens holder 3 and the outer holder 4 due to temperature change is used. Can be absorbed.
Further, in each of the embodiments described above, the described imaging device is installed in the imaging device installation unit H1 of the mobile phone H that is a portable device, as shown in FIGS.

  The imaging device according to the present invention can be applied to a drive module and an electronic device including the drive module in addition to a mobile phone as the mobile device H.

DESCRIPTION OF SYMBOLS 1 Imaging device 2 Lens 3 Lens holder 4 Outer holder 5 Frame 6 Support member (leaf spring)
7 Image sensor 11 Adhesive 12 Actuator

Claims (4)

A lens, a lens holder that accommodates the lens, a frame that includes a cylindrical outer holder that accommodates the lens via the lens holder, and a light receiving portion disposed at a center of the lens at a predetermined distance. An imaging device provided; a support member attached to an upper portion of the outer holder and the frame on the subject side; and elastically supporting the outer holder in the optical axis direction; and operating the lens holder and the outer holder in the optical axis direction. An imaging apparatus comprising: an actuator, wherein the support member has a thermal expansion coefficient larger than that of the outer holder, and at least the support member and the lens holder are fixed with an adhesive. The imaging apparatus according to claim 1, wherein the support member is configured to be deformed in a direction in which the lens holder expands and contracts while being bonded to the lens holder by the adhesive. The imaging apparatus according to claim 1, wherein the adhesive is an elastic adhesive. A portable device using the imaging device according to any one of claims 1 to 3.

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