JP2006080598A - Imaging module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging module capable of obtaining an image with high quality without being affected by unevenness of color filters or dust with a small-sized and simple structure. <P>SOLUTION: The imaging module is configured such that the module is provided with an optical member 2, a photoelectric conversion element 16 electrically connected to an electric wiring board 12, wherein the optical member and the photoelectric conversion element are supported by a support member in a way that the optical member and the photoelectric conversion element are opposed to each other, a dust-proof glass pane 9 is provided between the optical member and the photoelectric conversion element, and the color filters 11 are formed to the dust proof glass at the side of the photoelectric conversion element. In this case, at least part of the optical member is configured to be formed with a plurality of resin-made lenses to form images in respective colors and the color filters are arranged to be capable of coping with the lenses forming the color lights. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging module, and more particularly to an imaging module used by being incorporated in a portable device such as a mobile phone or a portable terminal device (PDA).

In recent years, a small imaging module in which an imaging lens is integrally provided with a CMOS sensor and a CCD sensor has been put into practical use mainly in mobile phones and information terminal devices. With the downsizing of mobile phones and information terminal devices, further downsizing of imaging modules is required. Among them, packaging including photoelectric conversion elements such as a CMOS sensor chip and a CCD sensor chip is the most important technology.
The current sensor chip package is a ceramic package using wire bonding, which is widely used because of its mass productivity and low cost. However, there is a limit from the viewpoint of miniaturization, and a sensor chip that can be further miniaturized or thinned. A package is sought.

For this reason, as a conventional example that has been reduced in size or thickness, for example, a sensor chip, an electric substrate, and dust-proof glass integrated as shown in Patent Document 1 are known. . As shown in FIG. 5, a TAB tape is bonded to one surface of an optical glass, and a CCD having a microlens formed on the surface is connected to the TAB tape via an anisotropic conductive film. A sensor chip package is formed by integration.
Patent Document 2 discloses an image pickup that can generate a color image by configuring an optical system provided for each color using the configuration of the sensor chip package of Patent Document 1 and synthesizing images picked up for each color. A module is disclosed. According to this, the focal length can be reduced to about ½ as compared with a normal optical system, and it is possible to achieve further reduction in thickness compared with the current optical system.
Japanese Patent No. 3307319 JP 2001-264854 A

  By the way, the above-mentioned conventional example of Patent Document 2 has the advantage that a color image can be generated, the focal length can be shortened, and the thickness can be further reduced. Because it is in the same position, it was not always satisfactory in the following points.

That is, in the one of Patent Document 2, as shown in FIG. 6A, the image pickup system arranged for the image pickup device includes an aperture, a color filter, and a photographing lens in order from the subject side. The color filter is provided at substantially the same position as the stop. FIG. 6B is a view of the photographing lens of FIG. 6A viewed from the light incident side.
The color filter has very fine irregularities, and image degradation may occur when the color filter is located at substantially the same position as the stop. In addition, when it is away from the aperture and close to the sensor, it is easily affected by dust and causes image deterioration. As a countermeasure, when assembly or the like is performed in a clean room, a problem arises in terms of an increase in equipment costs.

  The present invention has been made in view of the above problems, and an object thereof is to provide an imaging module that can obtain a high-quality image without being affected by unevenness or dust of a color filter with a small and simple structure. It is.

The present invention provides an imaging module configured as follows.
That is, the imaging module of the present invention includes an optical member and a photoelectric conversion element electrically connected to an electric wiring board, and is held by the holding member so that the optical member and the photoelectric conversion element face each other. In the imaging module, a dustproof glass is provided between the optical member and the photoelectric conversion element, and a color filter is formed on the photoelectric conversion element side of the dustproof glass.

  According to the present invention, it is possible to realize an imaging module that can obtain a high-quality image without being affected by unevenness or dust of the color filter with a small and simple structure.

The present invention is characterized by the above-described configuration. However, in the embodiment of the present invention, when the above-described configuration of the present invention is applied, the optical member is at least partially composed of a plurality of resin lenses. The structure to form can be taken.
Moreover, the structure which forms the said resin lenses in the other surface of the glass substrate which comprises the said optical member can be taken.
In addition, the plurality of resin lenses can be configured to have substantially the same focal length.
Each of the plurality of resin lenses may be a convex lens.
Further, the plurality of resin lenses are lenses that form light of different colors, and the color filters are arranged on the optical path of the optical system by the lenses so as to correspond to the colors of the lenses. Can be taken.
In addition, the color filter may be configured to be formed on the dust-proof glass surface by photolithography or printing.
Further, the optical member can be held by the holding member via an adhesive.

Examples of the present invention will be described below.
In the embodiment of the present invention, an imaging module capable of generating a color image by applying the above-described present invention is configured.
FIG. 1 is a schematic cross-sectional view showing the configuration of the imaging module of the present embodiment.
In FIG. 1, 1 is a flat optical glass and 2 is a lens part. The lens unit 2 is formed with a four-lens unit 3 and a base unit 4 on the optical glass 1 and images light of each color. Note that only two of the four-lens lenses are represented in the cross-sectional view of FIG.

The four-lens part 3 and the base part 4 made of an aspheric part can be easily formed by means such as replica molding.
When replica molding is used, it is generally molded with a photocurable resin made of acrylic or epoxy. In addition, since the lens part 2 molded in this way has a large volume ratio difference from the optical glass 1, the characteristics of the optical glass 1 are dominant in the coefficient of linear expansion, and even if the surrounding environment changes, the linear expansion coefficient is high. The shape of the four-lens unit 3 can be maintained with high accuracy.
Reference numeral 5 denotes a holding member that holds the optical glass 1 on which the lens portion 2 is formed, and the optical glass 1 is bonded and held by an adhesive 6.
Reference numeral 7 denotes an infrared cut layer that cuts harmful infrared light that degrades the image. The infrared cut layer 7 is formed by multilayer coating on the optical glass 1, and the lens portion 2 is formed on the infrared cut layer 7. Further, in order to efficiently transmit visible light, the infrared cut layer 7 sets the cut-off wavelength between the visible light wavelength to be transmitted and the near-infrared light wavelength to be opaque to 690 nm. Efficiency decreases. In order to suppress this decrease in efficiency within the limit, the accuracy of the cutoff wavelength is set to ± 20 nm.

FIG. 2 is a view of the optical glass 1 on which the lens portion 2, the infrared cut layer 7, and the aperture layer 8 are formed as seen from the upper surface side, and FIG. 3 is a view of them as seen from the lower surface side.
In FIG. 2, 8 is an aperture layer. In the diaphragm layer 8, four circular openings 8a, 8b, 8c, and 8d are observed. Although the aperture layer 8 can be easily formed integrally on the optical glass 1 by printing, it is possible to obtain a circular aperture with higher accuracy by using a photolithography process used for producing a black matrix of liquid crystal. .

On the other hand, in FIG. 3, the lens part 2 includes four aspherical parts 3 a, 3 b, 3 c, 3 d and one base part 4. For example, the aspherical surface 3a is aspherical corresponding to red, the aspherical surfaces 3b and 3c are green, and the aspherical surface 3d is blue, and each has an optimized shape according to the transmission wavelength for each color. Yes. In the figure, a region surrounded by diagonal lines is formed in an annular shape surrounding the lens unit 2 at the adhesive interface between the adhesive 6 and the optical glass 1.
Further, the adhesive 6 is formed so as not to contact the lens portion 2. This is because, when the adhesive 6 comes into contact with the lens unit 2, the adhesive 6 contracts and expands when the surrounding environment changes, and exerts an unreasonable stress on the lens unit 2.

  Further, the infrared cut layer 7 and the aperture layer 8 are not formed on the adhesive interface between the adhesive 6 and the optical glass 1 and the portion corresponding to the adhesive interface on the upper surface side of the optical glass 1. This is because when the imaging device is assembled, if an ultraviolet light curable adhesive is used as the adhesive 6, the adhesive 6 can be cured in a short time when it is desired to be cured. This is because if the infrared cut layer 7 or the diaphragm layer 8 that does not transmit ultraviolet light is present in the above-described portion, an ultraviolet curable adhesive cannot be used in the imaging apparatus.

  Returning to FIG. 1, the holding member 5 has a configuration in which a dustproof glass 9 is bonded and held by an adhesive 10. The color filter layer 11 is provided on the surface of the dust-proof glass 9 on the sensor chip 16 side. The color filter layer 11 can be formed on the surface of the dust-proof glass surface opposite to the sensor chip. However, when an ultraviolet curable adhesive or a thermosetting adhesive is used as the adhesive 10. However, the color filter layer interferes with the problem that the assembly time becomes long and the adhesive does not cure, and the adhesive is limited.

FIG. 4 is a view of the dust-proof glass 9 as seen from the sensor chip 16 side.
The color filter layer 11 includes color-specific filter portions indicated by 11a, 11b, 11c, and 11d. Since nothing is formed on the upper side of the color filter layer 11, it is not necessary to perform a flattening process. This makes it possible to achieve a significant cost reduction. Such color filters 11a, 11b, 11c, and 11d can be easily manufactured by using a photolithographic method used for manufacturing color filters such as CCDs. It can also be formed by means such as printing. The color filter 11a corresponds to the circular opening 8a and the aspheric surface 3a of the aperture layer. Similarly, 11b, 11c, and 11d correspond to the circular openings 8b, 8c, and 8d and the aspherical surfaces 3b, 3c, and 3d, respectively, of the diaphragm layer.

Again, returning to FIG. Reference numeral 12 denotes a flexible wiring board, which includes a base insulating sheet 13 and a copper foil pattern 14. As the insulating sheet 13, a composite substrate of polyimide / polyamide / polyester or phenol / glass epoxy resin and paper / glass base material is generally used. The flexible wiring board 12 is bonded and fixed to the holding member 5 via the adhesive 15.
Reference numeral 16 denotes a sensor chip having a light receiving region 17, and gold bumps 19 are formed on electrode pads 18 provided in the peripheral portion of the sensor chip 16. Then, it is electrically bonded to the flexible wiring board 12 through the anisotropic conductive paste 20.
21 is a sealing agent that seals the periphery of the sensor chip 16, and serves to prevent the surface of the sensor chip 16 from being deteriorated by contact with the outside air.
In this embodiment, the outside air is blocked by the anisotropic conductive paste 20, but the structure is sealed with the sealant 21 in order to further improve the reliability. The other adhesive 6, adhesive 10, and adhesive 15 are also completely sealed in order to prevent outside air from entering the imaging module.

  The imaging module in the present embodiment has the above-described configuration. According to this, not only can a small and ultra-thin imaging device be provided, but also a large equipment investment such as a clean room can be suppressed. A product with a high yield can be manufactured without restricting the location, and a high-quality image can be provided.

It is a schematic sectional drawing which shows the structure of the imaging module in the Example of this invention. It is the figure which looked at the optical glass shown by FIG. 1 from the upper surface side. It is the figure which looked at the optical glass shown by FIG. 1 from the lower surface side. It is the figure which looked at the dustproof glass shown by FIG. 1 from the sensor chip side. It is a figure which shows the structure of the imaging module disclosed by patent document 1 which is a prior art example. It is a figure explaining the image pick-up system of the image pick-up module disclosed by patent document 2 which is a prior art example, (a) is a figure explaining a diaphragm and a color filter positional relationship, (b) is light for the imaging lens of (a). It is the figure seen from the incident side.

Explanation of symbols

1: Optical glass 2: Lens part 3 (3a, 3b, 3c, 3d): Four-eye lens (aspherical part)
4: Base part 5: Holding member 6: Adhesive 7: Infrared cut layer 8 (8a, 8b, 8c, 8d): Drawing layer 9: Dust-proof glass 10: Adhesive 11 (11a, 11b, 11c, 11d): Color filter 12: Flexible wiring board 13: Insulating sheet 14: Copper foil pattern 15: Adhesive 16: Sensor chip 17: Light receiving area 18: Electrode pad 19: Gold bump 20: Anisotropic conductive paste 21: Sealant

Claims (8)

An imaging module comprising an optical member and a photoelectric conversion element electrically connected to an electric wiring board, and held by a holding member so that the optical member and the photoelectric conversion element face each other,
An imaging module, wherein a dustproof glass is provided between the optical member and the photoelectric conversion element, and a color filter is formed on the photoelectric conversion element side of the dustproof glass.   The imaging module according to claim 1, wherein at least a part of the optical member is formed of a plurality of resin lenses.   The imaging module according to claim 1, wherein the plurality of resin lenses are formed on the other surface of the glass substrate constituting the optical member.   The imaging module according to claim 1, wherein the plurality of resin lenses have substantially the same focal length.   The imaging module according to claim 2, wherein each of the plurality of resin lenses is a convex lens.   The plurality of resin lenses are made of lenses for imaging light of different colors, and the color filters are arranged on the optical path of the optical system by the lenses so as to correspond to the colors of the lenses. The imaging module according to claim 1, wherein the imaging module is characterized in that:   The imaging module according to claim 1, wherein the color filter is formed on the dust-proof glass surface by photolithography, printing, or the like.   The imaging module according to claim 1, wherein the optical member is held by the holding member via an adhesive.

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