JP2010278501A - Solid-state imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state imaging apparatus capable of suppressing stray light, preventing the generation of optical noise such as ghosts and flares, suppressing dust generation and providing high-quality images. <P>SOLUTION: The solid-state imaging apparatus includes: a solid-state imaging element in a chip structure for converting an object optical image to an image signal; a plate for fixing the solid-state imaging element; a circuit board on which the plate with the solid-state imaging element fixed thereto is loaded, and which drives the solid-state imaging element and performs prescribed processing to image signals from the solid-state imaging element; a frame member which has an opening in an area facing the light receiving surface of the solid-state imaging element and comprises a resin fixed to the circuit board and surrounding the solid-state imaging element; and a transparent member which covers the opening of the frame member. On the inner wall surface of the frame member, a plurality of corrugated light shielding lines are formed so as to circulate in the inner wall surface. Glass fibers are mixed in a resin material configuring the frame member, the fiber diameter of the glass fibers is ≥2 μm and ≤10 μm, and the fiber length is ≥200 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a solid-state imaging device.

  FIG. 3 shows a schematic configuration of an example of a conventional solid-state imaging device having a so-called chip-on-board structure in which a solid-state imaging device having a chip structure is mounted on a circuit board. FIG. 3 is a schematic cross-sectional view showing a schematic configuration of a conventional solid-state imaging device 1.

  A conventional solid-state imaging device 1 includes a chip-like solid-state imaging device 103 such as a CCD or CMOS sensor that converts a subject optical image formed by an optical system (not shown) into an image signal, and a base plate 102 that fixes the solid-state imaging device 103. The circuit board 101 on which the electrical components that drive the solid-state image sensor 103 and the electrical components that generate image data based on the image signal output from the solid-state image sensor 103 are mounted, and the light-receiving surface 103 a of the solid-state image sensor 103. A frame member 104 made of a resin surrounding the solid-state image sensor 103, a transparent member 105 covering the opening of the frame member 104, and the like. A bonding pad 106 is provided between the base plate 102 and the frame member 104 on the surface of the circuit board 101, and the solid-state imaging device 103 and the circuit board 101 are connected by a bonding wire 107.

  By the way, in the solid-state imaging device 1 having such a configuration, the light incident on the solid-state imaging device 1 may be reflected by the inner wall surface of the resin frame member 104 and become stray light and incident on the light receiving surface 103a of the solid-state imaging device 103. is there. As a result, there is a problem that optical noise such as ghost and flare occurs in the image and the quality of the image is impaired.

  Therefore, in order to cope with such a problem, in Patent Document 1, the frame member is made of an epoxy resin or ABS resin mixed with a light shielding filler such as a carbon black pigment, or is reflected on the inner wall surface of the frame member. A method for applying a protective film has been proposed.

  Furthermore, in Patent Document 1, a plurality of stepped steps whose opening shape increases as the distance from the transparent member increases on the inner wall surface of the frame member, and all light rays within a predetermined incident angle are externally formed by the steps. Has been proposed that prevents stray light from entering the light-receiving surface of the solid-state imaging device.

JP 2008-186875 A

  However, if the frame member is composed of an epoxy resin or ABS resin mixed with a light-shielding filler such as carbon black pigment, or only by applying an antireflection coating or the like on the inner surface of the frame member, It was not sufficient to suppress reflection and prevent stray light from entering the light-receiving surface of the solid-state imaging device.

  Further, when a plurality of stepped steps are formed on the inner wall surface of the resin frame member, there is a problem that it is difficult to ensure desired strength, rigidity, dimensional accuracy, and the like.

  The present invention has been made in view of the above problems, and provides a solid-state imaging device capable of suppressing stray light and preventing the generation of optical noise such as ghosts and flares, suppressing dust generation, and providing high-quality images. The purpose is to provide.

  The above object is achieved by the invention described in any one of 1 to 5 below.

1. A solid-state imaging device having a chip structure for converting a subject optical image into an image signal;
A base plate for fixing the solid-state imaging device;
A circuit board on which the base plate to which the solid-state image sensor is fixed is mounted, and which drives the solid-state image sensor and performs predetermined processing on the image signal from the solid-state image sensor;
A frame member made of a resin having an opening in a region facing the light receiving surface of the solid-state image sensor and surrounding the solid-state image sensor and being fixed to the circuit board;
A solid-state imaging device having a transparent member covering the opening of the frame member,
On the inner wall surface of the frame member, a plurality of concavo-convex shading lines are formed so as to go around the inner wall surface,
A glass fiber is blended in the resin material constituting the frame member, the fiber diameter of the glass fiber is 2 μm to 10 μm, and the fiber length is 200 μm or more.

  2. 2. The solid-state imaging device according to 1 above, wherein the inner wall surface of the frame member is covered with an antireflection film.

  3. 3. The solid-state imaging device according to 1 or 2, wherein the surface of the base plate is subjected to blackening treatment and / or satin treatment.

  4). 4. The solid-state imaging device according to any one of 1 to 3, wherein the surface of the area surrounded by the frame member of the circuit board is subjected to blackening processing.

  5. The solid-state imaging device according to any one of 1 to 4, wherein the resin material constituting the frame member is any one of polycarbonate resin, polystyrene resin, acrylic resin, and polyester resin.

  According to the present invention, a plurality of concavo-convex shading lines are formed on the inner wall surface of the frame member made of resin surrounding the solid-state imaging device so as to go around the inner wall surface. Thereby, it is possible to prevent light incident on the solid-state imaging device from being reflected on the inner wall surface of the frame member and becoming stray light and entering the light-receiving surface of the solid-state imaging element.

  Moreover, glass fiber was mix | blended with the resin material which comprises a frame member. Thereby, the intensity | strength of a frame member, rigidity, heat resistance, dimensional accuracy, etc. can be improved.

  On the other hand, by forming a light shielding line on a resin frame member containing glass fiber, the structure of the frame member becomes complicated, the residual stress after molding increases, and the glass fiber easily falls off. As a result, image quality may be impaired by dust generation. Therefore, according to the present invention, the glass fiber can be prevented from falling off by setting the fiber diameter of the glass fiber to 2 μm or more and 10 μm or less and the fiber length to 200 μm or more.

  As a result, it is possible to suppress stray light incident on the light receiving surface of the solid-state imaging device and prevent optical noise such as ghosts and flares, and to suppress dust generation and provide a high-quality image.

It is a cross-sectional schematic diagram which shows schematic structure of the solid-state imaging device which concerns on embodiment of this invention. It is a figure which shows the relationship between the diameter of glass fiber, and intensity | strength. It is a cross-sectional schematic diagram which shows schematic structure of the conventional solid-state imaging device.

  Hereinafter, a solid-state imaging device according to an embodiment of the present invention will be described with reference to the drawings. In addition, although this invention is demonstrated based on embodiment of illustration, this invention is not limited to this embodiment.

  A schematic configuration of a solid-state imaging device according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view illustrating a schematic configuration of the solid-state imaging device 1.

  As shown in FIG. 1, the solid-state imaging device 1 includes a solid-state imaging device 103, a base plate 102, a circuit board 101, a frame member 104, a transparent member 105, and the like.

  As the solid-state image sensor (hereinafter, also simply referred to as an image sensor) 103, a chip structure CCD or CMOS sensor that converts a subject optical image formed by an optical system (not shown) into an image signal can be used.

  The base plate 102 is made of ceramic and fixes the image sensor 103. The surface of the base plate 102 is subjected to processing for reducing the reflectance of light, for example, blackening processing, satin processing, and the like.

  The circuit board 101 is a printed board made of, for example, a glass epoxy resin on which electrical parts that drive the image sensor 103 and electrical parts that generate image data based on image signals output from the image sensor 103 are mounted. The circuit board 101 has a so-called chip-on-board structure on which a base plate 102 to which an imaging element 103 having a chip structure is fixed is mounted.

  As in the case of the base plate 102, the surface of the area surrounded by the frame member 104 of the circuit board 101 is subjected to a process for reducing the reflectance of light, for example, a blackening process such as applying a black resist. Yes.

  The frame member 104 is made of resin, has an opening in a region facing the light receiving surface 103 a of the image sensor 103, surrounds the image sensor 103, and is fixed to the circuit board 101. A plurality of irregularities are formed on the inner wall surface of the frame member 104 in order to prevent light incident on the solid-state imaging device 1 from being reflected by the inner wall surface of the frame member 104 and becoming stray light and entering the light receiving surface 103 a of the image sensor 103. A (sawtooth) light shielding line 104a is formed so as to go around the inner wall surface. Furthermore, the inner wall surface of the frame member 104 may be covered with an antireflection film.

  As a material of the frame member 104, for example, a polycarbonate resin, a polystyrene resin, an acrylic resin, a polyester resin, or the like which is a thermoplastic resin can be used. In addition, fillers such as glass fibers and carbon fibers are appropriately blended with these thermoplastic resins in order to increase strength, rigidity, heat resistance, dimensional accuracy, and the like. Details of the glass fiber will be described later.

  The transparent member 105 covers the opening of the frame member 104 and is bonded and fixed to the frame member 104 with, for example, an ultraviolet curable resin. Light from an optical system (not shown) enters the light receiving surface 103 a of the image sensor 103 through the transparent member 105.

  The transparent member 105 is preferably a member having a light transmittance of 80% or more in the visible light region (400 nm to 700 nm) and the near infrared region, and more preferably a member having 90% or more. As a material of the transparent member 105, glass, acrylic resin, polycarbonate, a cycloolefin unit-containing polymer, or the like can be used.

  A bonding pad 106 is provided between the base plate 102 and the frame member 104 on the surface of the circuit board 101, and the imaging element 103 and the circuit board 101 are connected by a bonding wire 107. The bonding pad 106 may be coated with a cured resin after the bonding wire 107 is connected in order to suppress bonding deterioration and stray light generation.

  Here, the detail of the glass fiber mix | blended with the thermoplastic resin which is the material of the frame member 104 is demonstrated.

  A thermoplastic resin compounded with glass fiber is used as a material, and a frame member that does not contain oblique rays, in other words, a flat surface that does not have a complicated structure on the inner wall surface of the frame member molded with thermoplastic resin. In this case, since the residual stress of the frame member is small, the blended glass fiber does not drop from the resin and generate dust. However, by forming the light shielding wire 104a on the resin frame member 104 containing glass fiber, the structure of the frame member 104 becomes complicated, the residual stress after molding increases, and the glass fiber is easily dropped. As a result, image quality may be impaired by dust generation.

  As described above, the glass fiber is blended in order to increase the strength, rigidity and the like with respect to the thermoplastic resin.

  The characteristics of a composite material in which glass fibers are blended with resin are greatly affected by the interface characteristics between the resin and glass fibers. However, the technology for controlling the interface characteristics is not yet complete.

  In the case of a composite material formed by mixing different substances, for example, the bonding force between resin and glass fiber is generally low. In other words, the glass fiber is held by adhesion and frictional force with the resin.

  Therefore, the inventors of the present application have made extensive studies on the adhesion and frictional force between the resin and the glass fiber, and as a result, the fiber length L of the glass fiber satisfies the following formula (1), thereby allowing the adhesion between the resin and the glass fiber. And found that the frictional force can be generally increased. And, it was found from the formula (1) that generally good results can be obtained when the fiber length L is 200 μm or more.

Fiber length L> k × Glass fiber tear stress / interface shear stress (1)
However,
k: 5 (constant obtained from experiment)
However, it is still not sufficient to set the fiber length L to 200 μm or more. This is because a defect inherent in the glass fiber is generated due to the residual stress after molding, the glass fiber is torn, and as a result, the fiber length L may be shorter than 200 μm.

  The number of glass fiber defects generated under the influence of the residual stress is reduced by reducing the fiber diameter D. That is, it is possible to prevent the glass fiber from being broken by the residual stress after molding by reducing the fiber diameter D of the glass fiber. Thereby, the strength of the glass fiber is improved, the occurrence of glass fiber with an unknown fiber length L can be prevented, and the length of the glass fiber in the resin can be controlled to a predetermined value or more.

  FIG. 2 shows the relationship between the fiber diameter D and the strength of the glass fiber. As shown in FIG. 2, it can be seen that the fiber strength is rapidly increased by setting the fiber diameter D to 10 μm or less. Therefore, in the embodiment of the present invention, the fiber diameter D is set to 2 μm or more and 10 μm or less. The lower limit of 2 μm is due to the processing limit.

  As described above, in the embodiment of the present invention, the fiber diameter D of the glass fiber is 2 μm or more and 10 μm or less, and the fiber length L is 200 μm or more.

  As described above, in the solid-state imaging device 1 according to the embodiment of the present invention, the inner wall surface of the frame member 104 made of resin surrounding the imaging element 103 has a plurality of concave and convex shapes (sawtooth shape) so as to go around the inner wall surface. A light shielding line 104a is formed. Thereby, it is possible to prevent the light incident on the solid-state imaging device 1 from being reflected by the inner wall surface of the frame member 104 and becoming stray light and entering the light receiving surface 103 a of the image sensor 103.

  Further, the resin material constituting the frame member 104 is mixed with glass fiber. Thereby, the strength, rigidity, heat resistance, dimensional accuracy, and the like of the frame member 104 can be increased.

  On the other hand, by forming the light shielding wire 104a on the resin frame member 104 mixed with glass fiber, the structure of the frame member 104 becomes complicated, the residual stress after molding increases, and the glass fiber is easily dropped. As a result, image quality may be impaired by dust generation. Therefore, the glass fiber can be prevented from falling off by setting the fiber diameter D of the glass fiber to 2 μm or more and 10 μm or less and the fiber length L to 200 μm or more.

  As a result, stray light incident on the light receiving surface 103a of the image sensor 103 can be suppressed, optical noise such as ghost and flare can be prevented, dust generation can be suppressed, and a high-quality image can be provided.

DESCRIPTION OF SYMBOLS 1 Solid-state imaging device 101 Circuit board 102 Base plate 103 Solid-state image sensor 104 Frame member 104a Shading line 105 Transparent member 106 Bonding pad 107 Bonding wire

Claims (5)

A solid-state imaging device having a chip structure for converting a subject optical image into an image signal;
A base plate for fixing the solid-state imaging device;
A circuit board on which the base plate to which the solid-state image sensor is fixed is mounted, and which drives the solid-state image sensor and performs predetermined processing on the image signal from the solid-state image sensor;
A frame member made of a resin having an opening in a region facing the light receiving surface of the solid-state image sensor and surrounding the solid-state image sensor and being fixed to the circuit board;
A solid-state imaging device having a transparent member covering the opening of the frame member,
On the inner wall surface of the frame member, a plurality of concavo-convex shading lines are formed so as to go around the inner wall surface,
A glass material is blended in the resin material constituting the frame member, the fiber diameter of the glass fiber is 2 μm or more and 10 μm or less, and the fiber length is 200 μm or more.   The solid-state imaging device according to claim 1, wherein the inner wall surface of the frame member is covered with an antireflection film.   3. The solid-state imaging device according to claim 1, wherein the surface of the base plate is subjected to blackening treatment and / or satin treatment.   4. The solid-state imaging device according to claim 1, wherein the surface of the area surrounded by the frame member of the circuit board is blackened. 5.   5. The solid-state imaging device according to claim 1, wherein the resin material forming the frame member is any one of a polycarbonate resin, a polystyrene resin, an acrylic resin, and a polyester resin.

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