JP2007227672A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure enough the adhesive strength of the adhesive portion interposed between the electric board and the imaging element of an imaging apparatus to give a reliability to the imaging apparatus, in the imaging apparatus having its bare-chip mounting structure for mounting its imaging element on its electric board. <P>SOLUTION: The imaging apparatus has a pixel region 21a, the imaging element 21 comprising a bare chip having an electrode 30 which is present in the same plane as the pixel region and is disposed in the portion adjacent to the pixel region, and an electric board 17 wherein it has an opening 17a, and the imaging element is disposed to cover the opening. Further, the board 17 has a connective pattern for connecting it with the electrode disposed near the edge of its opening, and an opening-inner-edge 17b of its opening is formed in the position separated in the direction of the pixel region from the electrode by a distance not shorter than 0.3 mm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus formed by bonding and fixing an image pickup element made of a bare chip and a protective glass to an electric substrate.

  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, in a conventional general imaging apparatus, bare chip mounting in which a bare chip (imaging device) made of a hard plate member is bonded to a flexible printed board, which is a flexible plate member, with an adhesive. Some are made up of structures.

In general, an image pickup element including a bare chip is designed so that the pixel area is as large as possible with respect to the chip shape. Therefore, a short gap is formed between the electrode provided on the surface adjacent to the pixel region on the same surface as the surface on which the pixel region of the bare chip (imaging device) is formed and the peripheral portion of the pixel region. There is a tendency to end up.
JP 2002-218293 A

  However, in the conventional imaging device having the bare chip mounting structure as described above, it may not be possible to secure sufficient adhesive strength at the bonding portion.

  For example, as shown in FIG. 10, in an imaging device having a bare chip mounting structure in which an imaging element 121 made of a bare chip and a flexible printed circuit board 117 are connected using an adhesive 131, the peripheral portion of the pixel region 121 a and the inner side of the electrode 130. When the distance from the end is set short, the portion inside the electrode 130 in the adhesion range C by the adhesive 131 between the imaging element 121 and the flexible printed circuit board 117, that is, the electrode 130 and the pixel. The adhesion range B ′ at the portion between the region 121a cannot be sufficiently secured. Therefore, in this case, there is a problem that sufficient adhesion reliability cannot be ensured.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an electric substrate and a bare chip in an imaging device having a bare chip mounting structure for mounting a bare chip (imaging element) on an electric substrate. It is to provide an imaging apparatus having sufficient reliability by sufficiently securing the bonding strength of the bonding part with the (imaging element).

  In order to achieve the above object, an imaging apparatus according to the present invention is an imaging apparatus comprising a bare chip having a pixel region and an electrode provided in a portion adjacent to the pixel region and in the same plane as the pixel region. An image sensor, an opening, the image sensor is disposed so as to cover the aperture, and a connection pattern disposed near the edge of the aperture to connect to the electrode. And an electric substrate on which the inner edge of the opening is formed at a position separated by 0.3 mm or more.

  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, sufficient adhesion strength at a bonding portion between the electric substrate and the bare chip (imaging element) is ensured and reliable. It is possible to provide an imaging device having the characteristics.

  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 an imaging apparatus according to an 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 essential part enlarged cross-sectional view showing a state in which the imaging element is bonded and fixed to the flexible printed board in the imaging apparatus of the present embodiment. FIG. 9 is an enlarged plan view of a main part when viewed from the direction of the arrow X shown 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, is attached to the main body 11. 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 fixing member 15 is a member that serves as a reference for positioning the imaging device with respect to the mirror box 10. 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 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 30 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. . The electrodes 30 are connected to connection patterns (not shown) of the flexible printed circuit board 17 by bumps, 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. Accordingly, the opening 17a is set to be larger than the pixel region 21a of the image sensor 21 and smaller than the outer shape of the image sensor 21 and inside the position where the electrode 30 is located. A connection pattern (not shown) connected to the electrode 30 of the image sensor 21 is formed in the vicinity of the edge of the opening 17a.

  The heat radiating member 20 is provided to release the heat accumulated in the image sensor 21. The heat radiating member 20 is formed of a plate-like 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 board 17 opposite to the surface to which the image pickup device 21 is fixed by an 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 the adhesive 31.

  That is, the periphery 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 the electrodes 30 (see FIG. 8)), except for the bump portion.

  More specifically, the adhesive 31 is between the imaging device 21 and the flexible printed circuit board 17 from the outer edge 21b of the imaging device 21 to at least an electrical connection portion between the connection pattern of the flexible printed circuit board 17 and the electrode 30 of the imaging device 21. In addition, it is annularly applied with a first band width along the periphery of the image sensor 21. That is, the adhesive 31 is applied around the opening 17 a of the flexible printed circuit board 17.

  The adhesive 31 is applied in a strip shape along the periphery of the image sensor 21 so as to wrap the electrical connection portion between the connection pattern of the flexible printed circuit board 17 and the electrode 30 from the outer edge 21 b of the image sensor 21. 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 by an adhesive 25.

  More specifically, the 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 details of the means for adhering the heat radiating member 20 to the fixing member 15 are not related to the present invention, and the description thereof will be omitted.

  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 and the image pick-up element 21 is explained in full detail below.

  As described above, the outer peripheral edge portion on the light receiving surface side of the image sensor 21 and the peripheral edge portion of the opening 17 a on the back surface side of the flexible printed circuit board 17 are bonded and fixed by the adhesive 31 that surrounds the periphery of the electrode 30. The This adhesive 31 is particularly an insulating one. The adhesive 31 is distributed in a band shape along the periphery of the image sensor 21 so as to wrap around the electrical connection portion between the connection pattern of the flexible printed circuit board 17 and the electrode 30 from the outer edge 21b of the image sensor 21. Insulation in the vicinity of the electrode 30 is ensured.

  Here, in the adhesion range (application range) of the image pickup element 21 and the flexible printed circuit board 17 by the adhesive 31, the adhesion range in the direction from the end of the electrode 30 to the inside, that is, the peripheral edge of the pixel region 21a is denoted by reference numeral. This is represented by A (see FIGS. 8 and 9).

  In addition, the distance from the end of the electrode 30 to the inner edge 17b of the opening 17a of the flexible printed circuit board 17 is indicated by a symbol B (see FIGS. 8 and 9).

  In the imaging apparatus of the present embodiment, as shown in FIGS. 8 and 9, the inner edge 17 b of the opening 17 a of the flexible printed circuit board 17 is set from the inner edge of the electrode 30 toward the peripheral edge of the pixel region 21 a. The position is set to be 3 mm or more away (B ≧ 0.3 mm).

  The adhesion range A in the direction from the end of the electrode 30 toward the peripheral edge of the pixel region 21a in the adhesion range by the adhesive 31 is between the electrode 30 and the inner edge 17b of the opening 17a of the flexible printed circuit board 17. That is, it is set so as to be within the range of the interval dimension B. That is, the adhesion range A is set to be smaller than 0.3 mm from the inner end portion of the electrode 30 (B ≧ 0.3 mm> A).

Further, when considering the dimensional tolerance of the opening 17a of the flexible printed circuit board 17, it is necessary to consider that the opening 17a is as small as the size variation. For example, when the dimensional tolerance of the opening 17a is ± 0.05 mm, the interval dimension B is
B ≧ 0.3mm + 0.05mm × 2
≧ 0.4mm
More preferably, it is set to. In other words, it can be said that the distance from the outer periphery of the pixel region 21a to the end of the electrode 30 is 0.4 mm or more.

  In consideration of the incident angle of the light ray D (see FIG. 9) incident on the pixel region 21a, the peripheral portion of the pixel region 21a and the inner edge portion 17b of the opening 17a do not overlap with each other and the pixel region 21a It is necessary to set the interval dimension B so that the size of the opening 17a is larger than the outer peripheral size.

  As described above, according to the above-described embodiment, the inner edge of the opening 17a of the flexible printed circuit board 17 is positioned 0.3 mm or more away from the end of the electrode 30 toward the pixel region 21a or 0.4 mm or more. Since the end portion 17b is set to be formed, a sufficient adhesion range of the adhesive 31 between the flexible printed circuit board 17 and the image pickup device 21 can be secured, and thus sufficient adhesive strength is ensured and reliability is ensured. It can be set as the imaging device provided with.

  In the above-described embodiment, 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 the above-described embodiment, 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 which is an electric substrate are bonded to each other using the insulating adhesive 31. However, 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 shows the state by which the image pick-up element was adhere | attached and fixed with respect to the flexible printed circuit board in the imaging device of this embodiment. The principal part enlarged plan view at the time of seeing from the arrow X direction of FIG. Sectional drawing which shows the outline of the bare chip mounting structure in the conventional imaging device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Mirror box 11 ... Main-body part 13 ... Body mount 13a ... Mount mounting surface 15 ... Aluminum plate 15a, 15b ... Hole 16 ... Protection member 17 ... Flexible printed circuit board 17a ... Opening 17b ... ... inner edge 20 ... heat dissipation member 21, 121 ... imaging element 21a, 121a ... pixel region 24 ... protective glass 25, 31, 32, 131 ... adhesive 30, 130 ... electrode

Claims (6)

In the imaging device,
An image sensor made up of a bare chip having a pixel region and an electrode that is on the same plane as the pixel region and is adjacent to the pixel region;
The imaging element is disposed so as to cover the opening, and has a connection pattern disposed in the vicinity of the edge of the opening and connected to the electrode. An electric substrate on which an inner edge of the opening is formed at a position separated by 3 mm or more;
An imaging device comprising: In the imaging device,
An image sensor made up of a bare chip having a pixel region and an electrode that is on the same plane as the pixel region and is adjacent to the pixel region;
The imaging element is disposed so as to cover the opening, and has a connection pattern disposed in the vicinity of the edge of the opening and connected to the electrode. An electric substrate on which an opening inner edge of the opening is formed at a position separated by 4 mm or more;
An imaging device comprising: In the imaging device,
An image sensor made up of a bare chip having a pixel region and an electrode that is on the same plane as the pixel region and is adjacent to the pixel region;
An electric board having an opening and the imaging element disposed so as to cover the opening, and a connection pattern arranged in the vicinity of the edge of the opening and connected to the electrode, the electric board and the imaging element Adhesive is applied in a belt shape along the periphery of the image sensor so as to wrap at least the electrical connection portion between the connection pattern and the electrode from the outer edge of the image sensor, and from the end of the electrode An electric substrate in which an opening inner edge of the opening is formed at a position separated by 0.3 mm or more toward the pixel region;
An imaging device comprising: In the imaging device,
An image sensor made up of a bare chip having a pixel region and an electrode that is on the same plane as the pixel region and is adjacent to the pixel region;
An electric board having an opening and the imaging element disposed so as to cover the opening, and a connection pattern arranged in the vicinity of the edge of the opening and connected to the electrode, the electric board and the imaging element Adhesive is applied in a belt shape along the periphery of the image sensor so as to wrap at least the electrical connection portion between the connection pattern and the electrode from the outer edge of the image sensor, and from the end of the electrode An electric substrate in which an opening inner edge of the opening is formed at a position separated by 0.4 mm or more toward the pixel region;
An imaging device comprising: The imaging apparatus according to claim 1, wherein the electric board is a flexible printed board. In the imaging device,
An electric board having an opening and a plurality of connection patterns around the opening;
In order to be electrically connected to the connection pattern, the pixel area has electrodes disposed on the same plane as the pixel area along the outer periphery of the pixel area and spaced apart from the pixel area by 0.4 mm. And an image sensor composed of a bare chip mounted on the electric substrate so as to cover the opening of the electric substrate,
An imaging device comprising:

Images