JP2010197816A - Camera module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera module, positioning and fixing an image pickup element and a lens group with high accuracy in simple constitution. <P>SOLUTION: This camera module includes: a base plate 60 where the image pickup element 61 is placed; a lens barrel member 10 fixed on the substrate 60; and a plurality of lenses 20, 40 housed in the lens barrel member 10. The positions of the plurality of lenses 20, 40 in the optical axis direction are fixed by abutting the optical axis direction reference surfaces of a plurality of optical elements including the plurality of lenses 20, 40 and the lens barrel member 10 in the optical axis direction. The position in the direction orthogonal to the optical axis of one lens 40 of the plurality of lenses 20, 40 is fixed by fitting accuracy of the one lens 40 and the optical axis center fitting part of the lens barrel member 10. The position in the direction orthogonal to the optical axis of lenses 20 other than the one lens 40 out of the plurality of lenses 20, 40 is fixed by fitting accuracy of the one lens 40 and the optical axis center fitting part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a camera module.

  Camera modules are installed in mobile phones and portable game machines, and are roughly divided into types that achieve a relatively high resolution of about 2 to 5 million pixels and types that realize a relatively low resolution of about 100,000 pixels. Is done. The present applicant is developing a so-called VGA (Video Graphic Array) camera module of the latter type (Patent Document 1).

  The camera module proposed by the present applicant in Patent Document 1 includes a substrate on which an image sensor is mounted, a base fixed on the substrate, and a lens barrel that holds a lens group that is fixed to the base and includes a plurality of lenses. And have. Screw portions that are screwed to each other are formed on the inner peripheral surface of the base and the outer peripheral surface of the lens barrel, and the screw portions (screwing amounts) of these screw portions are adjusted and placed on the substrate. The image sensor and the lens group are focused by moving the image sensor and the lens group held by the lens barrel relative to each other.

JP 2008-122636 A

  This camera module requires a step of positioning and fixing the lens group to the lens barrel, and a step of adjusting the position in the optical axis direction by screwing the lens barrel to the base on which the imaging element (substrate) is fixed. There was room for improvement in assembly workability.

  The present invention has been made on the basis of the above problem awareness, and an object of the present invention is to provide a camera module capable of positioning an image pickup element and a lens group with high accuracy with a simple configuration.

  The camera module of the present invention includes a substrate on which an image sensor is placed, a lens barrel member fixed on the substrate, and a plurality of lenses housed in the lens barrel member. The position in the optical axis direction is determined by abutting the optical axis direction reference planes of the plurality of optical elements including the plurality of lenses and the lens barrel member in the optical axis direction, and the optical axis of any one of the plurality of lenses The position in the orthogonal direction is determined by the fitting accuracy of the one lens and the optical axis center fitting portion of the lens barrel member, and is in the direction orthogonal to the optical axis of the lens other than the one lens of the plurality of lenses. The position is determined by the fitting accuracy of the optical axis center fitting portion with the one lens.

  In addition to the plurality of lenses, the plurality of optical elements may include a spacer member that is positioned between the substrate and the plurality of lenses, and whose front and back faces the imaging element on the substrate and the lens closest to the substrate. .

  Specifically, the plurality of lenses includes a first lens and a second lens sequentially inserted into the lens barrel member, and an optical axis center fitting portion is provided between the second lens and the lens barrel member. An optical axis center fitting portion can be provided between the lens and the second lens.

  The optical axis center fitting portion between the first lens and the second lens includes a reference protrusion formed from the lower surface of the first lens toward the upper surface of the second lens, and the lower surface of the first lens from the upper surface of the second lens. And a fitting outer cylindrical portion that fits with the inner cylindrical surface of the reference projection of the first lens.

  In a preferred aspect, the optical axis direction reference that abuts between the first lens and the lens barrel member, between the first lens and the second lens, between the second lens and the spacer member, and between the spacer member and the image sensor. A surface can be formed.

  The optical axis direction reference surface between the first lens and the second lens can be formed by the lower surface of the reference projection of the first lens.

  The reference projections of the first lens can be provided at intervals on a virtual circle outside the effective diameter of the first lens.

  The spacer member can be given a diaphragm function.

  According to the present invention, it is possible to obtain a camera module capable of positioning and fixing an imaging element and a lens group with high accuracy with a simple configuration.

It is a longitudinal cross-sectional view of the assembly completion state which shows one Embodiment of the camera module of this invention. FIG. 3 is a perspective view of a single lens barrel member of the camera module. It is a perspective view of the 1st lens single-piece | unit of the camera module. It is a perspective view of the 2nd lens single-piece | unit of the camera module. It is a perspective view of the spacer member single-piece | unit of the camera module. It is a perspective view in the middle of the assembly of the camera module. It is a perspective view which shows another state in the middle of the assembly of the camera module. It is a perspective view of the assembly completion state of the camera module.

  The camera module 100 of the present embodiment includes a lens barrel member 10, a first lens 20, a diaphragm plate 30, a second lens 40, a filter 70, and a spacer plate 50 that are inserted into the lens barrel member 10 in order. A substrate 60 on which the image sensor 61 is mounted is provided. The substrate 60 on which the image sensor 61 is mounted is supplied as a commercial product and is finally coupled to the lens barrel member 10. Elements other than the image sensor 61 are formed of a synthetic resin material. FIG. 1 shows an assembled state in which these elements are combined and combined. In the following description, for convenience, the upper part of FIG. 1 is the upper part of each element, the optical axis direction of the camera module 100 is the X direction, and the optical axis. The orthogonal direction is defined as the Y direction.

  Each element will be described. The lens barrel member 10 has a rectangular base frame portion 11 below and a cylindrical portion 12 having a smaller diameter than the rectangular base frame portion 11 as shown in FIG. The upper end portion of the cylindrical portion 12 is closed by an upper end plate portion 14 having a light beam intake hole 13. The rectangular frame portion 11 and the cylindrical portion 12 are connected by an optical axis orthogonal wall (light shielding wall) 15. The inner diameter D1 of the inner cylindrical surface (optical axis center fitting portion) 12A of the cylindrical portion 12 serves as a position reference in the Y direction perpendicular to the optical axis of the first lens 20 and the second lens 40, and is molded with high accuracy. ing. On the inner surface of the upper end plate portion 14, an annular optical axis X direction reference surface 14A is formed at the periphery. Hereinafter, “optical axis X direction reference plane” means a reference plane orthogonal to the optical axis X.

  As shown in FIG. 3, the first lens 20 has a positive meniscus lens portion 21 that is convex on the upper side of the central portion (the light beam inlet 13 side), and the positive meniscus lens portion 21. A plurality of arc-shaped reference projections (foot portions) 23 at the center of the optical axis (in the illustrated example, three at equal angular intervals) are formed below the annular flat plate portion 22. ing. The reference protrusion 23 is provided on a virtual circle outside the effective diameter portion (positive meniscus lens portion 21) of the first lens 20. The annular flat plate portion 22 has an outer diameter that fits with a large clearance with respect to the inner cylindrical surface 12A of the lens barrel member 10 (this clearance is exaggerated in FIG. 1). That is, the fitting portion between the annular flat plate portion 22 and the inner cylindrical surface 12A is not involved in the positional accuracy of the first lens 20 in the Y direction perpendicular to the optical axis. On the other hand, a discontinuous inner cylindrical surface (optical axis center fitting portion) 23A formed by a plurality of arc-shaped reference protrusions 23 is formed to have a diameter D2 with high dimensional accuracy. Around the upper surface of the annular flat plate portion 22, an optical axis X direction reference surface 22 </ b> A that contacts the optical axis X direction reference surface 14 </ b> A of the upper end plate portion 14 is formed, and inside the reference protrusion 23 on the lower surface of the annular flat plate portion 22. Constitutes a constriction gap forming surface 22B orthogonal to the optical axis, and the lower surface of the reference projection 23 constitutes the optical axis X direction reference surface 23B.

  As shown in FIG. 4, the second lens 40 is turned upside down, and a positive meniscus lens portion 41 convex to the upper side of the central portion (on the first lens 20 side) and the peripheral edge of the positive meniscus lens portion 41 are fitted. It has an outer cylindrical part 42 and a position determining annular part 43 at the periphery of the fitted outer cylindrical part 42. The fitting outer cylindrical portion (optical axis center fitting portion) 42 is fitted with high fitting accuracy into the inner cylindrical surface 23A of the reference projection 23 of the first lens 20, and this optical axis center fitting portion. Thus, the positional accuracy of the second lens 40 in the Y direction perpendicular to the optical axis with respect to the first lens 20 is obtained (the optical axes of the first lens 20 and the second lens 40 are correctly aligned). Further, the outer cylindrical surface (optical axis center fitting portion) 43A of the position determining annular portion 43 is fitted to the inner cylindrical surface 12A of the cylindrical portion 12 with high dimensional accuracy, and is relative to the cylindrical portion 12 of the lens barrel member 10. The position of the second lens 40 in the Y direction perpendicular to the optical axis is determined. That is, the first lens 20 and the second lens 40 fitted to the cylindrical portion 12 of the lens barrel member 10 have a fitting relationship between the inner cylindrical surface 12A and the position determining annular portion 43 (outer cylindrical surface 43A), and a reference. The position in the Y direction perpendicular to the optical axis is determined by the fitting relationship between the protrusion 23 (the inner cylindrical surface 23A) and the fitting outer cylindrical portion 42.

  An annular optical axis X direction reference surface 43 </ b> B is formed on the upper surface of the position determining annular portion 43. The optical axis X direction reference surface 43B is in contact with the optical axis X direction reference surface 23B of the reference projection 23 of the first lens 20 to determine the positions of the first lens 20 and the second lens 40 in the optical axis X direction.

  In addition, a plurality of arcuate reference projections (foot portions) 44 at the center of the optical axis (three in the illustrated example at equal angular intervals) are formed on the lower surface of the position determining annular portion 43. The lower surface constitutes an optical axis X direction reference surface 44A.

  An annular diaphragm gap forming surface 42A is formed on the upper surface of the fitting outer cylindrical portion 42 of the second lens 40, and between this diaphragm gap forming surface 42A and the diaphragm gap forming surface 22B of the first lens 20. The aperture housing gap (space) P (FIG. 1) is formed in a state where the optical axis X direction reference surface 23B of the reference protrusion 23 and the optical axis X direction reference surface 43B of the position determining annular portion 43 are in contact with each other. Yes. The aperture plate 30 made of a light shielding material is set to be thinner than the aperture storage gap P, and the outer diameter is slightly smaller than the diameter D2 of the inner cylindrical surface 23A formed by the plurality of reference projections 23. Yes. Accordingly, the diaphragm plate 30 is supported in a floating state (without being compressed) between the first lens 20 and the second lens 40, and the first lens 20 and the first lens 20 are supported by the central opening 31 of the diaphragm plate 30. The harmful light flux incident on the outside of the effective diameter of the second lens 40 can be shielded.

  The spacer plate 50 is accommodated in the rectangular frame portion 11 of the lens barrel member 10, and the first lens 20, the diaphragm plate 30, the second lens 40, and the filter 70 described above are attached to the lens barrel in the course of assembly. The first lens 20, the second lens 40, and the substrate 60 (imaging device 61) are held at correct positions in the state where the first lens 20, the second lens 40, and the substrate 60 (imaging device 61) are held in a state where the substrate 60 is coupled to the lens barrel member 10. . As shown in FIG. 5, the spacer plate 50 has a rectangular shape as a whole, and has a light transmission aperture 51 at the center, and a pair of temporary protrusions projecting in opposite directions at the periphery. A holding projection 52 is provided. The temporary holding projection 52 is formed with a U-shaped groove 53 that opens radially outward. On the upper and lower surfaces of the spacer plate 50, annular optical axis X direction reference surfaces 50A and 50B are formed. The light beam transmission aperture 51 has a diaphragm (aperture diaphragm) function together with the diaphragm plate 30. The inside of the reference projection 44 of the second lens 40 forms a recess 45 that forms a storage space for the filter 70 between the spacer plate 50 and the reference surface 50A in the optical axis X direction.

  On the other hand, a pair of protrusions 16 are formed on the inner surface of the rectangular frame portion 11 of the lens barrel member 10 so as to correspond to the U-shaped groove 53, and when the spacer plate 50 is fitted into the rectangular frame portion 11. At the same time, by fitting the protrusion 16 into the U-shaped groove 53, the position of the spacer plate 50 with respect to the rough rectangular frame portion 11 can be regulated (FIG. 6). In this state, when the tip of the protrusion 16 is heat caulked to form the heat caulking head 16P (FIG. 7), the spacer plate 50 is temporarily held with respect to the lens barrel member 10. In this state, even if the lens barrel member 10 is turned upside down, the first lens 20, the diaphragm plate 30, the second lens 40, the filter 70, and the spacer plate 50 in the lens barrel member 10 do not fall off.

  The peripheral edge of the substrate 60 is bonded and fixed to the opening end surface 11A of the rectangular frame portion 11 in a state where the imaging element 61 is inserted into the rectangular frame portion 11 of the lens barrel member 10 for which the above temporary assembly has been completed. . In the imaging element 61 positioned in the rectangular frame 11, a positioning surface (optical axis X direction reference surface) 61 </ b> A that is not related to imaging of the peripheral edge thereof is in contact with the optical axis X direction reference surface 50 </ b> B of the spacer plate 50. Due to this abutting force, the spacer plate 50 is pushed upward so that its optical axis X direction reference surface 50A comes into contact with the optical axis X direction reference surface 44A of the second lens 40. The optical axis X of all optical elements is determined by the contact relationship between the optical axis X direction reference surface 23B of one lens 20 and the contact relationship between the optical axis X direction reference surface 22A and the optical axis X direction reference surface 14A of the lens barrel member 10. The position of the direction is determined. As described above, the positions of the first lens 20 and the second lens 40 in the optical axis orthogonal Y direction are determined by fitting accuracy between the inner cylindrical surface 12A of the lens barrel member 10 and the outer cylindrical surface 43A of the second lens 40, and Since it is determined by the fitting accuracy of the reference projection 23 (inner cylindrical surface 23A) of one lens 20 and the fitting outer cylindrical portion 42 of the second lens 40, the optical axis X direction and the optical axis of all the optical elements are as described above. The position in the orthogonal Y direction is determined, and the subject image by the first lens 20 and the second lens 40 is correctly formed on the image sensor 61.

  The opening end surface 11A of the lens barrel member 10 is not the position reference of the substrate 60 (imaging device 61). That is, the dimension is set so that an exaggerated gap Q is generated between the substrate 60 and the opening end surface 11A when the imaging device 61 is inserted into the rectangular frame 11 of the barrel member 10. In the above positioning state, the two are bonded by the adhesive 17.

  In the camera module 100 having the above-described configuration, in the assembled state (use state), the photographing light beam that has entered the lens barrel member 10 from the light beam inlet 13 is the positive meniscus lens portion 21 and the second lens of the first lens 20. The light passes through the light transmission apertures 51 of the 40 positive meniscus lens portions 41, the filter 70 and the spacer plate 50, and forms an image on the image sensor 61. The position in the optical axis X direction and the position in the optical axis orthogonal Y direction of each optical element involved in image formation are controlled (secured) with high accuracy in the assembly process, and no adjustment is required.

  In the above embodiment, the spacer plate 50 is interposed between the second lens 40 and the image sensor 61 (substrate 60) as one of the optical elements inserted into the lens barrel member 10, but the second lens 40 The spacer plate 50 as a separate member can be omitted by integrally forming the corresponding portion of the spacer plate.

  In the above embodiment, since the inner cylindrical surface 23 </ b> A is configured by the arc-shaped reference projection 23, the fitting outer cylindrical portion (optical axis center fitting portion) of the second lens 40 by elastic deformation of the reference projection 23. However, the inner cylindrical surface may be constituted by a continuous annular reference protrusion.

  In the above embodiment, the present invention is applied to the camera module 100 in which two lenses (the first lens 20 and the second lens 40) are housed in the lens barrel member 10. The position in the direction perpendicular to the optical axis of any one lens is determined by the fitting accuracy of the one lens and the lens barrel member, and the position in the direction perpendicular to the optical axis of the lens other than this one lens is The present invention can be applied to a camera module using three or more lenses as long as the relationship defined by the fitting accuracy of the optical axis center fitting portion with the one lens is satisfied.

DESCRIPTION OF SYMBOLS 100 Camera module 10 Barrel member 11 Rectangular frame part 11A Open end surface 12 Cylindrical part 12A Inner cylindrical surface (optical axis center fitting part)
13 Light flux inlet 14 Upper end plate portion 14A Optical axis direction reference surface 15 Optical axis orthogonal wall 16 Projection 16P Heat caulking head 17 Adhesive 20 First lens 21 Positive meniscus lens portion 22 Annular flat plate portion 22A Optical axis direction reference surface 22B Aperture gap forming surface 23 Reference projection 23A Inner cylindrical surface (optical axis center fitting portion)
23B Optical axis direction reference plane 30 Diaphragm 31 Central opening 40 Second lens 41 Positive meniscus lens part 42 Fitting outer cylindrical part (optical axis center fitting part)
42A Aperture gap forming surface 43 Position determining annular portion 43A Outer cylindrical surface (optical axis center fitting portion)
43B Optical axis direction reference surface 44 Reference projection 44A Optical axis direction reference surface 50 Spacer plate 50A 50B Optical axis direction reference surface 51 Light beam transmission opening 52 Temporary holding projection 53 U-shaped groove 60 Substrate 61 Image sensor 61A Positioning surface (optical axis direction reference) surface)
70 Filter P Restriction storage gap (space)

Claims (8)

A substrate on which an image sensor is mounted;
A lens barrel member fixed on the substrate;
A plurality of lenses housed in the barrel member;
The positions of the plurality of lenses in the optical axis direction are determined by abutting the optical axis direction reference planes of the plurality of optical elements including the plurality of lenses and the lens barrel member in the optical axis direction,
The position in the direction orthogonal to the optical axis of any one of the plurality of lenses is determined by the fitting accuracy of the one lens and the optical axis center fitting portion of the lens barrel member,
The position of the plurality of lenses in the direction orthogonal to the optical axis of the lens other than the one lens is determined by the fitting accuracy of the optical axis center fitting portion with the one lens. module. The camera module according to claim 1,
The camera module, wherein the plurality of optical elements include a spacer member positioned between the substrate and the plurality of lenses, the front and back of which are abutted against the imaging element on the substrate and the lens closest to the substrate. The camera module according to claim 1 or 2,
The plurality of lenses includes a first lens and a second lens that are sequentially inserted into the lens barrel member, and an optical axis center fitting portion exists between the second lens and the lens barrel member, and the first lens and the second lens A camera module in which an optical axis center fitting portion exists between two lenses. The camera module according to claim 3,
The optical axis center fitting portion between the first lens and the second lens includes a reference protrusion formed from the lower surface of the first lens toward the upper surface of the second lens, and the lower surface of the first lens from the upper surface of the second lens. The camera module which consists of a fitting outer cylinder part fitted toward the inner cylindrical surface of the reference | standard protrusion of a 1st lens formed toward the direction. The camera module according to claim 4, wherein
A camera having optical axis direction reference surfaces that are in contact with each other between the first lens and the barrel member, between the first lens and the second lens, between the second lens and the spacer member, and between the spacer member and the imaging device. module. The camera module according to claim 5, wherein
An optical axis direction reference plane between the first lens and the second lens is configured by a lower surface of the reference projection of the first lens. The camera module according to any one of claims 4 to 6,
The camera module in which the reference protrusions of the first lens are provided at intervals on a virtual circle outside the effective diameter of the first lens. The camera module according to any one of claims 2 to 7,
The spacer member is a camera module having a diaphragm function.

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