JP4998689B2 - Optical equipment module - Google Patents

Description

  The present invention relates to an optical device module that communicates a substrate mounted with an optical element such as a CCD to the outside through a flexible substrate.

  In an optical device module equipped with an optical element of an imaging system such as a CCD or CMOS, a housing that houses the optical element and a lens is provided on a substrate. An optical part that enables mutual conversion of light and electrical signals is formed in CCDs and CMOSs that are optical elements. The housing holds the lens at a position corresponding to the optical part of the optical element. Further, the casing is attached so as to surround the optical element, whereby unnecessary light incident on the optical portion of the optical element can be cut.

  The optical element is mounted on a substrate and is transmitted to the outside as an electrical signal by a wiring pattern provided on the substrate. When the optical device module is employed as, for example, a camera function of a mobile phone, a flexible substrate is used to transmit an electrical signal from the substrate on which the optical element is mounted to the outside from the viewpoint of miniaturization. The optical element is mounted using a rigid (rigid = hard) substrate, for example, a glass epoxy substrate. And, as shown in the drawing of Conventional Example 1 in FIG. 4, the rigid substrate and the flexible substrate are connected by sandwiching both sides of the flexible substrate having the wiring pattern formed on both sides with the rigid substrate. By a method of connecting a wiring pattern of a flexible substrate with a through hole (Patent Document 1) or a method of crimping a conductor pattern of a flexible substrate to an end of a rigid substrate as shown in Conventional Example 2 in FIG. The wiring patterns are connected to each other.

JP 2005-85976 A

  Optical device modules for mobile phone cameras are required to be smaller. From the viewpoint of miniaturization, using a rigid substrate as the substrate on which the optical element is mounted is disadvantageous in terms of thickness. This is because the rigid substrate has a thickness of 500 μm or more.

  However, in the optical device module, when the distance between the lens mechanism and the optical element is changed, the focus is lost. Therefore, the distance between the lens mechanism and the optical element needs to be constant.

  For this reason, when the optical element is directly mounted on the flexible substrate, the flexible substrate is thin with a thickness of about 50 μm, so the flexible substrate may bend and the focal length may be changed.

  Thus, it is conceivable to reinforce the strength by making the flexible substrate multilayer, but the steps of the flexible substrate whose surfaces are covered with a resist layer and a coverlay are complicated by bonding them together.

  Therefore, an object of the present invention is to reduce the size of an optical device module with a simpler structure.

In order to achieve the above object, an optical device module according to the present invention includes a flexible substrate having a terminal for coupling to an optical element and having a wiring pattern on both surfaces coupled to the terminal, and the optical of the flexible substrate. A first resist layer formed on the element mounting surface; a coverlay layer applied to the optical element opposite mounting surface of the flexible substrate; an adhesive sheet affixed to the outside of the coverlay layer; and the adhesive Ri Do and a second resist layer to be applied to light-shielding on the outside of the sheet, the second resist layer is directly formed on the adhesive sheet used for bonding the flexible substrate to each other.

  Also, the optical element mounting area where the wiring pattern, flexible substrate, first resist layer, cover lay layer, adhesive sheet and second resist layer are laminated, and only the wiring pattern, flexible substrate and cover lay layer are extended. A cable region for transmitting an electrical signal to the outside.

  An optical device module according to the present invention includes a flexible substrate having a terminal for coupling to an optical element and having a wiring pattern on both surfaces coupled to the terminal, and a first resist formed on the optical element mounting surface of the flexible substrate. A layer, a coverlay layer applied to the optical element non-mounting surface of the flexible substrate, an adhesive sheet attached to the outside of the coverlay layer for reinforcement, and an outer side of the adhesive sheet for light shielding By forming the second resist layer, it is possible to manufacture a small optical device module with a simple structure, and it is possible to prevent the focal length from fluctuating due to the deflection of the flexible substrate.

  Also, the optical element mounting area where the wiring pattern, flexible substrate, first resist layer, cover lay layer, adhesive sheet and second resist layer are laminated, and only the wiring pattern, flexible substrate and cover lay layer are extended. By providing the cable region for transmitting an electric signal to the outside, it is possible to provide a simple and small-sized optical instrument module that includes a flexible cable.

  Furthermore, when the optical element is a CCD image sensor or a CMOS image sensor, it can be used as an image sensor for a mobile phone camera.

  Next, any optical element can be coupled by coupling the optical element and the wiring pattern via an electrode provided on the optical element and a terminal coupled to the wiring pattern.

  Subsequently, an anisotropic conductive material is interposed between the electrode and the terminal, so that permanent adhesion between the opposing electrode portions, conduction between the electrodes, and insulation between the electrode patterns are simultaneously formed.

  Since this anisotropic conductive material does not cover the vicinity of the optical element, it is possible to prevent light reception failure of the optical element.

  On the other hand, by interposing a metal between the electrode and the terminal, it is possible to reduce the material cost and improve the conductivity.

  On the other hand, since the electrical joint between the electrode and the terminal is sealed with the underfill material, the connection reliability between the optical element and the optical device module can be improved.

  In addition, a housing that contains the optical element may be mounted in the optical element mounting region. The optical element can be easily fixed and the components can be protected. In addition, the housing may be made of a material that does not transmit or transmit light. Unnecessary light can be prevented from entering. Further, this housing may be mounted with a lens in addition to the optical element. The positional relationship between the lens and the optical element can be easily fixed.

  Hereinafter, the optical device module according to the present invention will be described in detail with reference to FIGS. FIG. 1A is a longitudinal sectional view of a terminal portion of an optical device module according to the present invention, FIG. 1B is a longitudinal sectional view of a laminated portion, and FIG. 1C is a longitudinal sectional view of the entire module including a housing. FIG. 2 is a longitudinal sectional view of an optical element of the optical device module according to the present invention. FIG. 3 is a front view of the optical device module according to the present invention.

  The shape of the optical element 10 is formed in a rectangular parallelepiped shape. As shown in FIG. 2, the optical element has an optical portion 12. The optical portion 12 is a portion where light enters or exits. The optical portion 12 converts light energy and other energy (for example, electricity). That is, the optical part 12 has a plurality of energy conversion elements (light receiving elements / light emitting elements) 14. In the present embodiment, the optical portion 12 is a light receiving portion. In this case, the optical element is a light receiving chip (for example, an imaging chip). A plurality of energy conversion elements (light receiving elements or image sensor elements) 14 are two-dimensionally arranged so that image sensing can be performed. That is, in the present embodiment, the optical module is an image sensor (for example, a CCD or CMOS sensor). The energy conversion element 14 is covered with a passivation film 16. The passivation film 16 is light transmissive. When the optical element is manufactured as a semiconductor substrate, for example, from a semiconductor wafer, the passivation film 16 may be formed of a silicon oxide film or a silicon nitride film.

  The optical portion 12 may have a color filter 18. The color filter 18 is formed on the passivation film 16. Further, the planarizing layer 20 may be provided on the color filter 18, and the microlens array 22 may be provided thereon.

  A plurality of electrodes 24 are formed on the optical element. The electrode 24 is electrically connected to the optical portion 12. The electrode 24 has bumps formed on the pad, but may be only the pad. The electrode 24 is formed outside the optical portion 12. The electrode 24 may be arranged along a plurality of sides (for example, two or four sides facing each other) or one side of the optical element.

  A wiring substrate 30 shown in FIG. 3 has a wiring pattern 34 formed on a base substrate 32. The base substrate is a bendable material (for example, a polyimide substrate).

  The wiring pattern 34 may be formed on one surface of the substrate or may be formed on both surfaces. The wiring patterns formed on both surfaces are connected by through holes. The wiring pattern can be formed by applying a known technique such as a plating technique or an exposure technique. The wiring pattern is composed of a plurality of wirings. The wiring pattern includes a plurality of terminals serving as electrical connection portions. The terminal 38 may be an end of a wiring or a land. At least two of the terminals 38 may be electrically connected to each other. The optical element mounting surface 40 of the wiring board 30 is a resist. The resist layer 56 is covered except for a portion to be bonded to the electrode of the optical element, and it is important that a resist layer is formed around the optical element. A resist capable of preventing irregular reflection of light is used.

  As shown in FIG. 3, the wiring board 30 includes first and second portions 40 and 42. For example, the wiring board 30 may have a rectangular planar shape in a state of being flatly developed, and the first and second portions 40 and 42 may be arranged in the length direction of the wiring board 30.

The first portion 40 has an optical element mounting area. The second portion 42 functions as a cable for transmitting an electrical signal from the optical element 10 to the outside.

The optical element 10 mounted on the first portion 40 is electrically connected to the wiring pattern 34 via the electrode 24. As an electrical connection between the electrode 24 and the first terminal 38 , an anisotropic conductive material such as an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP) is used, and the conductive particles are connected to the electrode 24. And the first terminal 38 may be interposed. In that case, the optical portion is not covered with the anisotropic conductive material. Or you may achieve the electrical connection between both by metal joining by Au-Au, Au-Sn, solder, etc. The electrical connection portion is preferably sealed with an underfill material. Also in this case, the optical portion 12 is not covered with the underfill material.

As shown in FIG. 1, the surface of the flexible substrate 32 opposite to the mounting surface of the optical element 10 is covered with a cover lay 58, and an adhesive sheet 60 is attached to the cover lay 58. The adhesive sheet 60 is affixed at a position facing the optical element on the surface opposite to the surface on which the optical element of the flexible substrate 32 is mounted. By providing the adhesive sheet 60, even if the flexible substrate 32 is reinforced and the optical element is mounted, it is possible to prevent the optical device module according to the present invention from being bent by the optical element as a whole.

A resist layer 62 is also formed on the adhesive sheet 60. The resist layer 62 is for light shielding that prevents the optical signal from being transmitted to the optical element on the substrate surface through the flexible substrate 32 from the back side of the optical element.

  In general, the adhesive sheet 60 is usually used for bonding flexible substrates to each other, and a resist layer is not directly formed on the adhesive sheet 60. However, in the present invention, the resist layer 62 is directly formed on the adhesive sheet 60. Is forming.

  As shown in FIG. 1, the optical instrument module has a housing 64. In the example shown in FIG. 1, the housing 64 is provided on the first part side of the wiring board. The housing 64 is preferably formed of a material that does not transmit or does not transmit light. The housing 64 holds a lens. When the housing 64 and the lens are used for imaging, they can be referred to as an imaging optical system. The lens 66 is disposed at a position corresponding to the optical portion 12 of the optical element 10.

  The housing has a shape surrounding the optical part of the optical element. In the example shown in FIG. 1, the housing 64 has a planar shape surrounding the optical element.

2A is a longitudinal sectional view of a terminal portion of the optical device module according to the present invention, FIG. 2B is a longitudinal sectional view of a laminated portion, and FIG. 3C is a longitudinal sectional view of the entire module including a housing. It is a longitudinal cross-sectional view of the optical element of the optical equipment module which concerns on this invention. It is a front view of the optical equipment module which concerns on this invention. It is a longitudinal cross-sectional view of the prior art example 1 of an optical apparatus module. It is a longitudinal cross-sectional view of the prior art example 2 of an optical equipment module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Optical element 12 Optical part 14 Energy conversion element (light receiving element / light emitting element)
16 Passivation film 18 Color filter 20 Flattening layer 22 Micro lens array 24 Electrode 30 Wiring substrate 32 Pace substrate 34 Wiring pattern 38 Terminal 40 Optical element mounting surface 56 Resist layer 58 Coverlay 60 Adhesive sheet 62 Direct resist layer 64 Housing 66 Lens

Claims (2)

A flexible substrate having a terminal for coupling to the optical element and having a wiring pattern on both sides coupled to the terminal;
A first resist layer formed on the optical element mounting surface of the flexible substrate;
A coverlay layer applied to the optical element opposite mounting surface of the flexible substrate;
An adhesive sheet affixed to the outside of the coverlay layer for reinforcement;
Ri Do and a second resist layer to be applied to light-shielding on the outside of the adhesive sheet,
An optical device module in which the second resist layer is directly formed on the adhesive sheet used for bonding the flexible substrates to each other .   An optical element mounting region in which a wiring pattern, a flexible substrate, a first resist layer, a cover lay layer, an adhesive sheet, and a second resist layer are stacked, and an electric signal by extending only the wiring pattern, the flexible substrate, and the cover lay layer. The optical device module according to claim 1, further comprising a cable region that transmits the light to the outside.

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