JP4818750B2 - Imaging device - Google Patents

Description

  The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus formed by bonding a fixing member and a unit in which an image pickup element made of a bare chip is bonded and fixed to an electric substrate with an adhesive.

  Conventionally, a subject image formed on the basis of a light beam from a subject incident on a photographing optical system is received by an image pickup device (for example, a charge coupled device (CCD) or the like) including a bare chip arranged at a predetermined position. 2. Description of the Related Art Electronic devices such as digital cameras configured to form an image on a surface and record the subject image as image data of a predetermined form are generally put into practical use and widely used.

  As an imaging device incorporated in a digital camera or the like, there is a bare chip mounting structure as disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-218293 (see FIG. 2).

  That is, a flexible printed circuit board (FPC) is bonded to the protective glass using an adhesive. In this flexible printed circuit board, an image pickup element made of a bare chip is connected to the surface opposite to the bonding surface to which the protective glass is bonded via electrode pads and bumps. In this case, the light receiving surface of the image sensor is disposed so as to face the protective glass.

  An adhesive is applied to the electrode pads and bumps so as to cover them. As a result, the flexible printed circuit board and the image sensor are adhesively bonded, and a sealing structure for the light receiving surface (pixel region) of the image sensor is formed.

  As described above, conventionally, a structural member such as a bare chip (imaging element) made of a hard plate member or a protective glass is bonded and fixed to the flexible printed circuit board which is a flexible plate member by an adhesive. There is a bare chip mounting structure.

And the imaging device (imaging unit) unitized in this way is incorporated in various electronic devices, such as a digital camera, for example, and bears the imaging function of the device.
JP 2002-218293 A

  However, the imaging device (imaging unit) having the above-described structure basically has a configuration in which various components such as an imaging element and a protective glass are assembled to a flexible printed board having flexibility. . Therefore, when the imaging device is incorporated in an electronic device such as a digital camera, it is difficult to reliably position the imaging device with respect to the device body.

  Further, depending on the assembling means of the image pickup device, there arises a problem that the flatness of the light receiving surface (also referred to as image pickup surface) of the image pickup device is broken due to excessive stress applied to the image pickup device constituting the image pickup device. There is a possibility.

  For example, FIG. 22 is an enlarged cross-sectional view of a main part showing an embodiment when an imaging apparatus having a conventional structure as described above is fixed to a device body.

  As shown in FIG. 22, the imaging apparatus according to this embodiment mainly includes an imaging element 121, a flexible printed circuit board 117 that is an electric board having an opening 117 a, and a protective glass 124.

  In this case, the vicinity of the inner edge of the opening 117a is connected to the outer peripheral edge of the image sensor 121 on one surface of the flexible printed circuit board 117 via electrodes and bumps. The outer peripheral edge of one surface of the protective glass 124 is bonded and fixed to the other surface of the flexible printed circuit board 117 (the surface opposite to the surface on which the image sensor 121 is mounted) with an adhesive 132. . The outer peripheral edge of the other surface of the protective glass 124 is fixed by pressure to a predetermined reference surface of the fixing member 140 on the electronic device side.

  When the fixing means according to such a form is applied, for example, if a predetermined external force is applied to the fixing member 140, the external force is applied to the protective glass via the contact surface between the fixing member 140 and the protective glass 124. A reaction force in a direction along the arrow F1 shown in FIG. Thereby, for example, the reaction force in the direction along the arrow F2 shown in FIG. Therefore, this may cause a problem such as the image sensor 121 being distorted or warped.

  FIG. 23 is an enlarged cross-sectional view of a main part showing another embodiment when the imaging device having the conventional structure as described above is fixed to the apparatus main body.

  As shown in FIG. 23, the imaging apparatus according to another embodiment is mainly configured by an imaging element 121, a flexible printed circuit board 117 which is an electric board having an opening 117a, and a protective glass 124. This is the same as the above-described imaging apparatus (see FIG. 22).

  In the imaging device of this embodiment, a plurality of hard fixing members 141 are bonded and fixed to the other surface of the flexible printed circuit board 117 (the same surface as the surface on which the protective glass 124 is disposed) by an adhesive 132. The fixing member 141 is fixed to a structure of the electronic device by a predetermined means.

  When the fixing means in such a form is applied, for example, if an external force along the direction of arrow F3 in FIG. 23 is applied to the fixing member 141, the external force F3 is applied to the fixing member 141 and the protective glass on the flexible printed circuit board 117. It acts as a reaction force along the direction of arrow F4 in FIG. At this time, since the fixing member 141 is fixed to the apparatus, the reaction force in the direction of the arrow F4 further acts as a reaction force in the direction along the arrow F2 shown in FIG. . Accordingly, this may cause problems such as distortion and warping of the image sensor 121.

  On the other hand, a means for fixing an image pickup unit in which a flexible printed circuit board, an image pickup device, a protective glass and the like are unitized to a plate-like fixing member using an adhesive by surface bonding is also conceivable.

  However, with this means, the film thickness of the adhesive is increased at the bonding site between the image sensor and the fixing member, and the film thickness may be, for example, 0.1 mm or more. Furthermore, it is difficult to keep the film thickness of the adhesive constant.

  If the film pressure of the adhesive becomes unstable, there is a possibility that the distance between the reference surface of the fixing member and the light receiving surface of the image sensor varies. Then, there is a problem in that an image acquired using the imaging apparatus may have an adverse effect on the imaging result, such as deteriorating the image quality, such as one-sided blur.

  Specifically, for example, FIG. 24 is an enlarged cross-sectional view of a main part showing an embodiment in which the imaging device having the above-described structure is fixed to a plate-like fixing member by surface bonding using an adhesive. It is.

  As shown in FIG. 24, the imaging apparatus according to this embodiment is mainly configured by an imaging element 121, a flexible printed circuit board 117 that is an electric board having an opening 117a, and a protective glass 124. 22 is the same as that of the imaging apparatus shown in FIG.

  In the imaging apparatus of the present embodiment, a fixing member made of a plate-like hard member (for example, an aluminum material) with an adhesive 132 on the back surface side (the surface opposite to the connection surface with respect to the flexible printed circuit board 117) of the image sensor 121. 115 is bonded and fixed by pressure bonding using surface bonding. As the adhesive 132, for example, an epoxy-based thermosetting or light-curing adhesive is used.

  In this case, the following changes are observed at the adhesion site. FIG. 25 is an enlarged cross-sectional view of a main part showing a state of an adhesion portion between the imaging element and the fixing member immediately after application of the adhesive. FIG. 26 is an enlarged cross-sectional view of a main part showing a state of an adhesion portion between the imaging element and the fixing member after the adhesive is cured.

  First, after the adhesive 132 is applied to the back surface side of the imaging element 121, the fixing member 115 is attached to the application site, and pressure is applied to the adhesion site for a predetermined time (pressure bonding, FIG. 25). State shown). In this state, heat is applied to the adhesive 132. As a result, the adhesive 132 is cured while shrinking.

  In this case, since the image pickup device 121 and the fixing member 115 have greatly different physical properties (for example, stress strain and linear expansion coefficient), the contraction action of the adhesive 132 is different from that of the image pickup device 121 at the bonded portion. Stress is generated in a direction substantially orthogonal to each plane of the fixing member 115. This stress becomes a force attracting each other as shown in FIG.

  Thereby, as shown in FIG. 26, either or both of the image sensor 121 and the fixing member 115 may be distorted or warped with respect to the planar state. In this case, for example, if the distance between the imaging element 121 and the fixing member 115 via the adhesive 132 is the distance D (see FIG. 26), a part that is partially smaller than the distance D is generated.

  On the other hand, it has the same configuration as that of the imaging device of one embodiment shown in FIG. 24, and in addition to this, a flat plate member that guides and releases the heat accumulated in the imaging device 121 to the back surface side of the imaging device 121. Some of them have a heat dissipating member 120. The example shown in FIG. 27 is an enlarged cross-sectional view of a main part showing another embodiment different from FIG.

  In this case, after the flexible printed circuit board 117, the protective glass 124, and the image sensor 121 are assembled, the heat radiating member 120 is fixed to the rear surface side of the image sensor 121 by an adhesive 132 by free bonding. The fixing member 115 is fixed by pressure bonding with an adhesive 132.

  That is, in the form shown in FIG. 27, the adhesive 132 is applied to the back surface of the heat radiating member 120, and the fixing member 115 is attached thereto by pressure bonding.

  Also in this case, the imaging element 121 may be distorted or warped through the heat dissipation member 120 due to a contraction action when the adhesive 132 is cured, as in the case of the imaging apparatus of one embodiment shown in FIG.

For example, when surface bonding is performed using a thermosetting epoxy adhesive, when the film thickness of the adhesive is 0.1 mm and the curing shrinkage is 4%,
0.1mm x 4% = 0.004mm
Will contract. Actually, since the curing distribution of the adhesive is not uniform, the amount of shrinkage varies depending on, for example, the application shape of the adhesive, that is, the shape such as the film thickness and the adhesion area.

  The present invention has been made in view of the above-described points, and an object of the present invention is to fix with an adhesive in an imaging apparatus having a bare chip mounting structure for mounting a bare chip (imaging element) on an electric substrate. Even if external force is applied to the electric substrate without breaking the flatness of the bare chip (imaging device) when fixing the member, the bare chip (imaging device) is not deformed due to the stress, and sufficient adhesive strength It is to provide an imaging apparatus having a configuration capable of fixing a fixing member.

In order to achieve the above object, an imaging device according to one embodiment of the present invention includes an electrical substrate having an opening, an imaging element including a bare chip mounted on the electrical substrate so as to cover the opening, has an opening which faces the back side of the mounting surface of the imaging device, and a fixing member which is fixed to the image pickup device is contact adhesive only on the open mouth is affixed.

  According to the present invention, in an imaging apparatus having a bare chip mounting structure for mounting a bare chip (imaging element) on an electric substrate, the flatness of the bare chip (imaging element) is not lost when the fixing member is fixed by an adhesive. Even if an external force is applied to the electric substrate, an image pickup apparatus having a configuration capable of fixing the fixing member with sufficient adhesive strength without causing deformation of the bare chip (image pickup element) due to the influence of the stress can be provided.

  The present invention will be described below with reference to the illustrated embodiments.

  1 and 2 are views showing a mirror box portion of a digital single-lens reflex camera (hereinafter simply referred to as a digital camera) to which the imaging apparatus according to the first embodiment of the present invention is applied. Among these, FIG. 1 is a perspective view of the mirror box portion excluding the body mount and other unnecessary mechanism portions. 2 is a cross-sectional view taken along line [II]-[II] in FIG. FIG. 3 is a front view showing the configuration of the imaging apparatus of the present embodiment. 4 and 6 are exploded perspective views showing the configuration of the imaging apparatus of the present embodiment. Among these, FIG. 4 is a view seen from the front side. FIG. 6 is a view as seen from the back side. 5 and 7 are perspective views in a state in which the imaging device according to the present embodiment is assembled. Among these, FIG. 5 is a view seen from the front side. FIG. 7 is a view from the back side. FIG. 8 is an enlarged cross-sectional view of a main part illustrating an enlarged bonding portion between an imaging unit in which an imaging element and a protective glass are bonded and fixed to a flexible printed board and a fixing member in the imaging device of the present embodiment. 9 and 10 are enlarged cross-sectional views of the main part showing a part of FIG. 8 further enlarged. Among these, FIG. 9 shows a state immediately after applying an adhesive by an adhesive application method (potting) to the back surface side of the image sensor. FIG. 10 shows a state after a predetermined time has elapsed from the state of FIG. 9 and the adhesive has hardened. 9 and 10 show a cross section corresponding to a portion along line [8]-[8] in FIG.

  As shown in FIG. 1, a mount mounting surface 13 a on which a body mount 13 (not shown in FIG. 1, see FIG. 2) is mounted on the front surface of the main body 11 of the mirror box 10. The body mount 13 is provided to make a photographic lens barrel (not shown) having a photographic optical system detachable from the main body 11. Therefore, when a lens barrel (not shown) is attached to the body mount 13, the optical axis O (see FIG. 2) of the imaging optical system of the lens barrel passes through a substantially central portion of the body mount 13. In addition, the mount surface of the body mount 13 is set to be a surface substantially orthogonal to the optical axis O of the photographing optical system.

  Behind the main body 11, the image pickup apparatus according to the present embodiment, which includes an imaging element 21 and the like described later, and includes a fixing member 15, a protection member 16, a flexible printed circuit board 17 (FPC), and the like, Are fixed.

  The imaging apparatus of the present embodiment is mainly configured by a fixing member 15, a protection member 16, a flexible printed board 17, a heat radiating member 20, an imaging element 21, a protective glass 24 and the like as shown in FIGS. 2 to 5.

  The configuration will be described in more detail. In the imaging apparatus, the protection member 16, the flexible printed board 17, the heat radiation member 20, the imaging element 21, and the protection glass 24 are unitized in a state where they are assembled according to predetermined procedures. The fixing member 15 is fixed to the unit using an adhesive 32 (described later, see FIG. 8 and the like).

  The fixing member 15 is a member that serves as a reference for positioning the imaging device with respect to the mirror box 10. That is, the fixing member 15 serves as a fixing member fixed to the mirror box 10 in a state where the imaging unit is fixed.

  Note that the fixing member 15 is formed of a plate-like hard member, for example, a metal member such as an aluminum material, a stainless steel material, ceramic, a molded part, or the like.

  The fixing member 15 is provided with a hole 15a which is an opening having a substantially circular shape, for example, at a substantially central portion thereof. A hole 15b having a slightly smaller diameter than the hole 15a is formed in the vicinity of the hole 15a. The holes 15b are arranged one by one at portions facing each other across the hole 15a.

  The protection member 16 is fixed to the flexible printed circuit board 17. And the protection member 16 protects from the stress which arises when the flexible printed circuit board 17 bends with respect to the adhesion part of the image pick-up element 21, the protective glass 24, and the flexible printed circuit board 17, or when the said imaging device is assembled. This is used for positioning the flexible printed circuit board 17 with respect to the fixing member 15.

  The imaging element 21 is a photoelectric conversion element that performs a photoelectric conversion process for generating an image signal corresponding to an optical subject image formed through a photographing optical system (not shown). The imaging element 21 is formed of a bare chip such as a charge coupled device (CCD). A pixel region 21 a (see FIG. 8) is formed on one surface (light receiving surface) of the image sensor 21. A plurality of electrodes are provided on the same surface as the surface on which the pixel region 21 a is formed and adjacent to the pixel region 21 a, that is, in the vicinity of the outer peripheral edge around the image sensor 21. This electrode is connected to a connection pattern (not shown) of the flexible printed circuit board 17 by a bump 30, so that signals are transmitted and received between the flexible printed circuit board 17 and the image sensor 21.

  The flexible printed circuit board 17 is an electric board provided to supply an image signal generated by the photoelectric conversion process by the image sensor 21 to an electric circuit (not shown) such as an image processing circuit. A substantially rectangular opening 17 a (see FIG. 4) is formed in a substantially central portion of the flexible printed circuit board 17. The opening 17a is provided to allow a light beam to be imaged to pass therethrough. Therefore, the opening 17a is set to be larger than the pixel region 21a of the image sensor 21, smaller than the outer shape of the image sensor 21, and inside the position where the electrode is located. A connection pattern (not shown) connected to the electrode of the image sensor 21 is formed in the vicinity of the edge of the opening 17a.

  The heat dissipating member 20 is provided to release the heat accumulated in the image sensor 21 and is disposed in close contact with the image sensor 21 so as to be integrated therewith. The heat radiating member 20 is formed of a flat plate member such as ceramic.

  The protective glass 24 is a protective cover that is provided to protect the imaging region of the imaging element 21 by being provided at a portion that is larger in outer shape than the imaging element 21 and is opposed to the light receiving surface (imaging region) of the imaging element 21. . The protective glass 24 is formed of a transparent member such as flat glass.

  The protective glass 24 is fixed to the surface of the flexible printed circuit board 17 opposite to the surface to which the imaging element 21 is fixed by a second adhesive 25 so as to cover the opening 17a.

  As shown in FIG. 2, a high frequency component is generated on the front side of the protective glass 24 from a light beam (hereinafter referred to as an auxiliary vehicle light beam) from a subject that is transmitted through a photographing optical system (not shown). An optical low-pass filter (hereinafter abbreviated as “optical LPF”) 26 to be removed and a shutter 27 for controlling the irradiation time of the subject light beam incident on the light receiving surface of the image sensor 21 are sequentially arranged. Yes.

  The member arrangement of each constituent member in the imaging apparatus of the present embodiment is as follows.

  On one surface of the flexible printed circuit board 17, that is, the back surface side, the image sensor 21 is disposed so as to cover the opening 17 a. In this case, the flexible printed circuit board 17 and the image sensor 21 are at least mechanically fixed by a first adhesive (not shown).

  In other words, the peripheral edge of the opening 17a on the back surface side of the flexible printed circuit board 17 and the outer peripheral edge on the same surface as the one surface of the image sensor 21, that is, the light receiving surface (pixel region 21a) are electrodes (FIG. 8). Bonding is performed with a first adhesive (not shown) except for the bump portion of (see).

  More specifically, the first adhesive (not shown) includes the imaging element 21 and the flexible printed circuit board from the outer edge of the imaging element 21 to at least an electrical connection portion between the connection pattern of the flexible printed circuit board 17 and the electrode of the imaging element 21. It is applied annularly with a first band width between 17 and along the periphery of the image sensor 21. That is, the first adhesive (not shown) is applied around the opening 17 a of the flexible printed circuit board 17.

  And a 1st adhesive agent is apply | coated so that the circumference | surroundings of an electrode may be covered. Thereby, the image pickup device 21 is arranged so that the pixel region 21a of the image pickup device 21 is exposed from the opening 17a in a state where the image pickup device 21 is fixed to a predetermined part on the back side of the flexible printed circuit board 17.

  The other surface of the flexible printed circuit board 17, that is, the front surface side and the peripheral edge portion of the opening 17 a and the outer peripheral edge portion on the back surface side of the protective glass 24 are bonded together by a second adhesive 25.

  More specifically, the second adhesive 25 is annularly applied around the opening 17a of the flexible printed circuit board 17 with a second band width. In addition, as the adhesive 25 used in this portion, for example, an ultraviolet curable type is applied.

  By bonding the protective glass 24 and the flexible printed circuit board 17, a sealing structure is formed that seals the space in the vicinity of the light receiving surface of the image sensor 21 to the outside and protects the light receiving surface from the outside. ing.

  On the other hand, the heat radiating member 20 is bonded to the back surface side of the image sensor 21, that is, the surface opposite to the light receiving surface of the image sensor 21 with an adhesive (see FIG. 2).

  Further, the fixing member 15 is bonded and fixed to the rear surface side of the heat radiating member 20 with an adhesive 32 through a hole 15 a formed in the fixing member 15. The holes 15 b are used when the heat radiating member 20 is bonded to the fixing member 15.

  The fixing member 15 is fixed to a predetermined part of the main body 11 by means such as screwing. Accordingly, the image pickup device 21 is thereby fixed to a predetermined part of the main body 11 of the mirror box 10.

  Next, the adhesion site | part of the flexible printed circuit board 17, the protective glass 24, and the image pick-up element 21 is explained in full detail below.

  As shown in FIG. 8, the outer peripheral edge portion on the light receiving surface side of the image sensor 21 and the peripheral edge portion of the opening 17a on the back surface side of the flexible printed circuit board 17 are bonded and fixed by an adhesive (not shown). Yes. In particular, an insulating material is used as the adhesive. Accordingly, the insulating adhesive is distributed so as to cover the periphery of the electrode, so that the insulating property in the vicinity of the electrode is ensured.

  A protective glass 24 is bonded and fixed to the surface of the flexible printed circuit board 17, that is, the surface opposite to the surface on which the image sensor 21 is mounted, with an adhesive (not shown) so as to cover the opening 17 a. Yes. In this case, the adhesive is interposed between the vicinity of the outer peripheral side of the protective glass 24 and the peripheral edge portion of the opening 17 a of the flexible printed circuit board 17.

  On the back surface side of the image sensor 21, the heat radiating member 20 is fixed by surface bonding by free bonding using an adhesive 32. And the fixing member 15 is adhere | attached on the back surface side of this heat radiating member 20 by application | coating of the adhesive agent 32 by the adhesive agent application | coating method (potting) in the hole 15a. As the adhesive 32, a light curable or thermosetting epoxy adhesive, a one-component thermosetting epoxy adhesive, or the like is used.

  Here, the procedure for bonding the heat radiating member 20 to the fixing member 15 will be described in more detail.

  The above-described procedure, that is, an imaging unit in which the protective glass 24 and the imaging element 21 are bonded to a predetermined part with respect to the flexible printed circuit board 17 and the heat radiation member 20 is bonded to the imaging element 21 is fixed to the fixing member 15. It adheres using the adhesive agent 32 with respect to this site | part.

  In this case, first, in a state where the imaging unit and the fixing member 15 are aligned, both are brought into a pressurized state. And it sets so that the back surface of the fixing member 15, ie, the surface of the side shown in FIG. At this time, a part of the back surface side of the heat radiating member 20 is exposed from the holes 15a and 15b.

  In this state, for example, an instantaneous adhesive is applied to the heat radiating member 20 from the two holes 15b. Then, the heat radiating member 20 and the fixing member 15 are fixed. As a result, the imaging unit and the fixing member 15 are temporarily fixed at a predetermined position. Here, the pressurized state is released.

  Subsequently, an adhesive 32 is applied to the holes 15a by an adhesive application method (potting). The state at this time is the state shown in FIG. In the state shown in FIG. 9, a process of curing the adhesive 32 by performing heating or predetermined light irradiation is performed. As a result, the adhesive 32 is cured while shrinking, and is in a state as indicated by an arrow A in FIG. At this time, the stress generated by the contracting action by the adhesive 32 is relaxed on the surface of the adhesive 32 itself. Therefore, the stress generated when the adhesive 32 is cured does not affect other components.

  That is, the shrinkage of the adhesive by the adhesive application method (potting) can absorb the curing shrinkage in the exposed large area portion by exposing the shrinking portion of the adhesive. Bonding by this potting is a means by which the shrinkage stress at the time of curing of the adhesive is not easily transmitted to the adherend because the area where the adhesive touches the adherend is small.

  Further, the conventional means for bonding by surface bonding has a problem that the spread of the adhesive (application area) is not stable due to the application amount of the adhesive, the pressure applied to the adherend, and the like.

  On the other hand, in the bonding means by potting, since the coating is performed in a frame having a prescribed size, that is, in the hole 15a, the coating shape of the adhesive is always stable, and the coating area is also stable. Accordingly, this also stabilizes the shrinkage stress when the adhesive is cured.

  By the way, the image sensor 21 is formed by a plate member made of a silicon wafer having a plate thickness of about 0.65 mm, for example. Therefore, it has the property of being very easily deformed in the warping direction, that is, the direction substantially orthogonal to the plate plane. For this reason, when the imaging element 21 is fixed to the fixing member 15 which is a fixing member by surface bonding, the imaging element 21 tends to be easily deformed due to the influence of shrinkage stress generated when the adhesive 32 is cured.

  Therefore, in the present embodiment, as described above, the image pickup device 21 (the heat dissipating member 20 that is surface-bonded to the image pickup device 21 in this embodiment) and the fixing member 15 are bonded together by potting the adhesive 32, thereby the adhesive. 32 is devised to reduce the shrinkage stress. Further, in this case, the potting portion is limited by the hole 15a so that the shrinkage stress at the time of adhesion hardening is reduced.

  As described above, reducing the adhesion area can also reduce the amount of adhesion force. In consideration of this, in this embodiment, sufficient adhesive force is secured by using, for example, a one-component thermosetting epoxy adhesive (hereinafter referred to as an epoxy adhesive).

  The adhesive strength of the epoxy adhesive may cause cohesive failure of the adhesive when bonding to a metal member. This cohesive failure is a phenomenon caused by the fact that the cohesive force of the adhesive itself is smaller than the interfacial adhesion force of the metal member. If the cohesive fracture strength at this time satisfies the required strength as a product, it can be said that there is no problem in strength. For example, there is no problem in strength as a product as long as an adhesive strength of 10 times or more of the product weight is secured.

  Moreover, the epoxy adhesive has a property that it has a high adhesive force and adhesion reliability to metal members (except for stainless steel, brass, etc.) and is difficult to be deformed against external stress. For example, the elongation at break, which represents the amount of elongation until the adhesive breaks when stress is applied to the adhesive, is several percent or less for an epoxy adhesive. In general, it can be seen that the silicon adhesive is more difficult to deform than the elongation at break of more than 100%.

  Therefore, if the required amount of adhesive force is ensured and the elongation at break is several percent, even if an external force is applied, the influence of the imaging element 21 to be bonded using this is warped to a minimum. It becomes possible to suppress. It is known that the external stress applied to the image sensor 21 is about several hundred grams (g) when this is used for a digital camera. Therefore, when bonding the imaging element 21 (heat radiation member 20) and the fixing member 15 using an epoxy adhesive, it is considered that the required adhesive strength is sufficiently satisfied.

  By the way, in the above-described embodiment, the heat dissipating member 20 is interposed between the imaging element 21 and the fixing member 15. In this case, the heat radiating member 20 and the fixing member 15 are fixed by adhesion by potting of the adhesive 32. On the other hand, the imaging element 21 and the heat radiating member 20 are fixed to each other by surface bonding using an adhesive 32. Therefore, it is also conceivable that either or both of the imaging element 21 and the heat radiating member 20 are deformed by the shrinkage stress when the adhesive 32 is cured in the surface-bonded portion.

  However, both the image sensor 21 and the heat radiating member 20 are formed of members having substantially the same physical properties (for example, stress strain and linear expansion coefficient) although the compositions are not exactly the same. From this, it is considered that deformation such as distortion and warpage does not occur between the image sensor 21 and the heat dissipation member 20.

  On the other hand, when the part composed of the image pickup element 21 and the heat radiating member 20 is bonded to the fixing member 15, the physical properties of the fixing member 15 and the physical properties of the heat radiating member 20 directly bonded thereto are greatly different. Therefore, in this case, if the adhesive is fixed by surface bonding, there arises a problem of deformation due to shrinkage stress when the adhesive 32 is cured. Therefore, in this embodiment, as described above, a stress relaxation measure is taken in which the fixing member 15 is provided with the hole 15a and the adhesive 32 is potted there.

  As described above, according to the first embodiment, the protective glass 24 and the image pickup device 21 are bonded to the predetermined portion of the flexible printed circuit board 17 and the heat dissipation member 20 is bonded to the image pickup device 21. In order to reliably arrange the image pickup unit at a predetermined position with respect to an electronic apparatus such as a digital camera, the image pickup apparatus has a configuration in which a fixing member 15 made of a hard member is bonded and fixed to the image pickup unit.

  When the imaging apparatus is incorporated in an electronic device such as a digital camera, the fixing member can be used as a positioning reference with respect to the device main body, so that the image sensor fixed to the fixing member is reliably positioned with respect to the device main body. be able to.

  When the imaging unit is fixed to the fixing member 15, an epoxy adhesive 32 is potted in the hole 15 a formed in the fixing member 15. Accordingly, the shrinkage stress generated when the adhesive 32 is cured affects the heat radiating member 20 (indirectly, the imaging element 21) while securing a sufficient adhesive strength while reducing the adhesion area. There is no effect. Therefore, deformation of the adherend can be suppressed by the shrinkage stress of the adhesive 32.

  In the first embodiment described above, the adhesive 32 is directly interposed between the heat radiating member 20 and the fixing member 15. However, as described above, the heat radiating member 20 includes the imaging element 21. And the physical properties are substantially the same. Therefore, although the heat dissipation member 20 is provided on the back side of the image sensor 21, it can be considered as part of the image sensor 21.

  Next, an imaging device according to a second embodiment of the present invention will be described below.

  FIG. 11 is an enlarged cross-sectional view of a main part in the imaging apparatus according to the second embodiment of the present invention. Specifically, in the imaging apparatus according to the present embodiment, the adhesion portion between the imaging unit and the fixing member in which the imaging element and the protective glass are bonded and fixed to the flexible printed board is enlarged and shown.

  The basic configuration of this embodiment is substantially the same as that of the first embodiment described above. The present embodiment is different only in that the heat dissipating member is omitted from the constituent members of the imaging unit in the first embodiment described above. Therefore, the same configurations as those in the first embodiment described above are denoted by the same reference numerals, detailed description thereof is omitted, and only different portions will be described below.

  As shown in FIG. 11, in the imaging apparatus of the present embodiment, a protective glass 24 is bonded and fixed to one surface of the flexible printed circuit board 17 so as to cover the opening 17a. In addition, an imaging element 21 made of a bare chip is bonded and fixed to the other surface of the flexible printed circuit board 17 so as to cover the opening 17a. The fixing member 15 is bonded and fixed to the back surface side of the imaging element 21 by potting the adhesive 32 in the hole 15a.

  In this case, the bonding procedure between the image sensor 21 and the fixing member 15 is the same as the bonding procedure between the heat radiation member 20 and the fixing member 15 in the first embodiment. Other configurations are the same as those in the first embodiment described above.

  As described above, in the second embodiment, the same effect as that of the first embodiment described above can be obtained when the imaging unit having the heat dissipation member 20 omitted and the fixing member 15 are bonded. Obtainable. However, the first embodiment including the heat dissipating member 20 is a more preferable form. This is because the heat distribution for the image sensor 21 can be made uniform.

  In the first and second embodiments described above, the fixing member 15 is provided with a hole 15 a for potting the adhesive 32. The hole 15a has a substantially circular shape and is formed at a substantially central portion of the fixing member 15. However, the shape of the hole 15a and the position in the fixing member 15 are not limited to the above example.

  For example, FIG. 12 shows a first modification of the shape and position of the potting hole of the fixing member. 13 and 14 show cross sections along line [13]-[13] in FIG. Among these, FIG. 13 shows a state immediately after application of the adhesive, and FIG. 14 shows a state after the adhesive is cured.

  As shown in FIG. 12, in the fixing member 15 </ b> A of this modified example, in a region corresponding to the imaging element 21 (or a heat dissipation member) of the imaging unit that is an adherend, Two holes 15Aa made up of rectangular long holes are formed.

  In this case, the area of the hole 15Aa itself can be increased, and it is fixed at two locations, so that a larger amount of adhesive force can be obtained.

  FIG. 15 shows a second modification of the shape and position of the potting hole of the fixing member. 16 and 17 are cross-sectional views taken along the line [16]-[16] in FIG. Among these, FIG. 16 shows a state immediately after application of the adhesive, and FIG. 17 shows a state after the adhesive is cured.

  As shown in FIG. 15, in the fixing member 15 </ b> B of this modified example, a portion in the region corresponding to the image pickup device 21 (or a heat radiating member) of the image pickup unit that is an adherend, and a substantially central portion of the region. In addition, one rectangular hole 15Ba is formed.

  Furthermore, FIG. 18 shows a third modification of the shape and position of the hole for potting the fixing member. 19 is a cross-sectional view taken along the line [19]-[19] in FIG.

  As shown in FIG. 18, in the fixing member 15 </ b> C of this modification, the adhesive 32 is applied to the hole 15 </ b> Ca formed in the same shape and position as the above-described second modification (FIG. 15). It is different. That is, as shown in FIG. 19, from the back surface side of the imaging element 21 exposed in the hole 15Ca of the fixing member 15C to a part of the surface on the back surface side of the fixing member 15C through the inner wall surface of the hole 15Ca of the fixing member 15C. The adhesive 32 is applied over the entire area. And the application location is apply | coated to two locations which oppose in the inner edge of hole 15Ca.

  FIG. 20 shows a fourth modification of the shape and position of the potting hole of the fixing member. 21 is a cross-sectional view taken along line [21]-[21] in FIG.

  As shown in FIG. 21, in the fixing member 15 </ b> D of the present modification example, the fixing member 15 </ b> D is in an area corresponding to the imaging element 21 (or a heat radiating member) of the imaging unit that is an adherend, A substantially circular hole 15Da is formed in each part of the part. In this case, the diameter, that is, the area of each hole 15Da is set to be slightly smaller than in the case of each of the above-described embodiments and modifications.

  In this case, by arranging the plurality of holes 15Da substantially evenly in the adhesion region of the adherend, the necessary adhesion area can be secured while reducing the area of each hole 15Da.

  In each of the above-described embodiments, as an application example of the protective glass 24, a transparent member such as a plate-shaped glass is used. However, the present invention is not limited to this. As an example of the protective glass 24, a low-pass filter, for example, or an infrared cut filter can be similarly applied.

  In each of the above-described embodiments, the flexible printed circuit board 17 is used as an example of the electric board, but the present invention is not limited to this. As an application example of the electric substrate, for example, the same applies even when a hard thin substrate or the like is applied.

  Further, in the above-described position embodiment, the imaging element 21 and the flexible printed circuit board 17 that is an electric board are bonded using an insulating adhesive, but the present invention is not limited to this. For example, the image sensor 21 and the flexible printed circuit board 17 may of course use an adhesive containing conductive particles having conductivity by pressing.

The perspective view which takes out and shows the mirror box part of the digital single-lens reflex camera to which the imaging device of one embodiment of the present invention is applied. Sectional drawing which follows the [II]-[II] line | wire of FIG. 1 is a front view illustrating a configuration of an imaging apparatus according to an embodiment. FIG. 2 is an exploded perspective view illustrating the configuration of the imaging apparatus according to the present embodiment from the front side. The perspective view which looked at the state which assembled the imaging device of this embodiment from the front side. The disassembled perspective view which shows the structure of the imaging device of this embodiment from the back side. The disassembled perspective view which shows the state which assembled the imaging device of this embodiment from the back side. The principal part expanded sectional view which expands and shows the adhesion | attachment site | part of the imaging unit and fixing member by which the imaging element and the protective glass were adhere | attached and fixed with respect to the flexible printed circuit board in the imaging device of this embodiment. The principal part expanded sectional view of the state immediately after apply | coating the adhesive agent further expanding and showing a part of FIG. The principal part expanded sectional view of the state after further enlarging and showing a part of FIG. 8 and the adhesive agent hardening. FIG. 11 is an enlarged cross-sectional view of a main part in the imaging apparatus according to the second embodiment of the present invention. The figure which shows the 1st modification about the shape and position of the hole for potting of a fixing member in the imaging device of this invention. FIG. 13 is a cross-sectional view taken along line [13]-[13] in FIG. 12 and shows a state immediately after application of an adhesive. FIG. 13 is a cross-sectional view taken along line [13]-[13] in FIG. 12 and shows a state after the adhesive is cured. The figure which shows the 2nd modification about the shape and position of the hole for potting of a fixing member in the imaging device of this invention. FIG. 16 is a cross-sectional view taken along line [16]-[16] in FIG. 15 and illustrates a state immediately after application of an adhesive. FIG. 16 is a cross-sectional view taken along the line [16]-[16] in FIG. 15 and shows a state after the adhesive is cured. The figure which shows the 3rd modification about the shape and position of the hole for potting of a fixing member in the imaging device of this invention. Sectional drawing which follows the [19]-[19] line | wire of FIG. The figure which shows the 4th modification about the shape and position of the hole for potting of a fixing member in the imaging device of this invention. Sectional drawing which follows the [21]-[21] line | wire of FIG. The principal part expanded sectional view which shows one form at the time of fixing the imaging device of a conventional structure to an apparatus main body. The principal part expanded sectional view which shows another form at the time of fixing the imaging device of a conventional structure to an apparatus main body. The principal part expanded sectional view which shows one form at the time of adhering the imaging device of a bare chip mounting structure to a plate-shaped fixing member using the adhesive agent by surface bonding. The principal part expanded sectional view which expands and shows a part of FIG. 24, and shows the mode of the adhesion | attachment site | part of the image pick-up element and fixing member immediately after application | coating of an adhesive agent. The principal part expanded sectional view which shows the mode of the adhesion | attachment site | part of an image pick-up element and a fixing member after expanding and showing a part of FIG. 24 and the adhesive agent hardened | cured. The principal part expanded sectional view which shows another form at the time of fixing the imaging device of the form different from FIG. 24 to a plate-shaped fixing member using the adhesive agent by surface bonding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Mirror box 11 ... Main-body part 13 ... Body mount 13a ... Mount mounting surface 15,15A, 15B, 15C, 15D, 115,140,141 ...... Fixing member 15a, 15Aa, 15Ba, 15Ca, 15Da 15b... Hole 16... Protection member 17 and 117... Flexible printed circuit board 17 a and 117 a... Opening 20 and 120. 25, 32, 132 …… Adhesive 27 …… Shutter 30 …… Bump

Claims (6)

In the imaging device,
An electrical substrate having an opening;
An image sensor comprising a bare chip mounted on the electric substrate so as to cover the opening;
Has an opening which faces the back surface of the mounting surface of the imaging device, a fixed member contact adhesive only on the open mouth is affixed is fixed to the image pickup device,
An imaging device comprising: In the imaging device according to claim 1,
The imaging apparatus, wherein the opening of the fixing member is provided at a plurality of locations. In the imaging device according to claim 1,
The image pickup apparatus, wherein the electric board is a flexible printed board. In the imaging device according to claim 1,
Furthermore, a light transmission member is fixed to the electric substrate on a surface opposite to the surface on which the imaging element is mounted so as to cover the opening of the electric substrate. In the imaging device,
An electrical board having an imaging aperture through which the imaging luminous flux passes;
An imaging device mounted on the electric substrate so as to cover the imaging aperture;
A flat plate member bonded to the back surface of the mounting surface of the imaging element;
Has an opening, the junction surface between the image pickup device of the flat plate member are opposed to opening on the opposite side, a fixed member only adhesives to the open mouth is secured to the flat plate member is affixed ,
An imaging device comprising: In the imaging device according to claim 5,
The image pickup apparatus, wherein the flat plate member is a heat radiating member that guides and releases heat accumulated in the image pickup device.

Images