JP2004179736A - Camera module and mounting apparatus of the camera module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera module capable of realizing height reduction by attaining a low profile of a lens configuration section in the height direction while simplifying the focus adjustment and to provide a mounting apparatus of the camera module. <P>SOLUTION: An imaging element 9 with a light receiving section 10 is bare-chip-mounted on the lower side of a substrate 8. A lens holder 7 is mounted on and fixed to the upper side of the substrate 8. A mirror lens 2 formed with a concave mirror (first mirror) 3 and a convex mirror (second mirror) 4 is screwed to a female screw 6 of an inner wall of the lens holder 7. A reflection preventing coating is applied to a face forming a male screw 5 of the mirror lens 2. Turning a mirror lens system can fine-adjust the focus and reflecting an optical path length can make the thickness of the lens system thin. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a camera module used for a portable communication device such as a mobile phone, a portable information terminal such as a PDA, a digital camera, and more particularly, to a photographic lens system of the camera module.
First, the "device with a camera module" used in the name of the present invention is defined as a camera, a portable communication device, and a portable information terminal.
[0002]
[Prior art]
There is a demand for further miniaturization of a built-in camera module used for a mobile phone. Conventional miniaturized camera modules have reduced the dimensions of the image sensor by adopting a method in which bare chips are directly mounted on a substrate, and it is necessary to reduce the size of the lens in order to further reduce the size. Become.
At present, the lens portion is only a stack of concave and convex refraction lenses, and there is no structure that actively reduces the dimension of the lens portion in the height direction.
[0003]
FIG. 6 is a sectional view showing an example of a conventional camera module.
The lens barrel 69 to which the lens 71 and the optical filter 70 are attached is fixed to the holder 68 by screws. Similarly, a metal plate 64 having a hole is adhered on the flexible substrate 74 in which the hole is formed, and a holder 68 is fixed thereon. The imaging device 61 having the light receiving unit 65 mounted thereon is attached to the lower surface of the flexible substrate 74. The bump 66 is arranged on the electrode portion of the image sensor 61 and is pressed. A sealing resin (underfill agent) 67 is applied thereon.
[0004]
In this example, when the underfill agent flows toward the light receiving portion of the image sensor, the inflow cannot be prevented, and the lens unit including the lens, the lens barrel, and the holder requires the specifications required at that time. Each of them must be designed exclusively, and the problem is that the development efficiency is low. Further, since the lens unit 62 is configured to be bonded and mounted on the metal plate 64, it is necessary to perform an operation for determining the accuracy of the positioning of the optical filter 70 and the lens 71, and the height of the lens may be increased.
In order to solve each of the above problems, the present inventors have proposed a small module camera (Patent Document 1).
[Patent Document 1] Japanese Patent Application No. 2002-188942
FIG. 7 is a cross-sectional view showing the configuration of the camera module proposed above, in which the imaging device and the lens are improved to reduce the size of the entire camera module.
The imaging device 82 having the light receiving portion 83 formed thereon is electrically connected to the lower surface of the ceramic substrate 86 by a bump 84 so as to face the optical system housing portion 87, and an underfill agent 85 is applied thereon.
An IR cut filter 88 is mounted on a projection 86a provided at the lower end of the optical system housing 87, and the projection 86a prevents the underfill agent 86 from flowing into the light receiving section. A screw 81a is formed on the outer periphery of the lens 81, and the lens 81 is screwed onto a screw 86b provided on the inner wall of the optical system housing portion 87 of the ceramic substrate 86, thereby attaching the lens 81 to the ceramic substrate 86 and adjusting the focus. It can be performed.
[0006]
[Problems to be solved by the invention]
According to this proposal, it is possible to prevent the underfill agent from flowing, and it is not necessary to perform an operation for determining the accuracy of the positioning of the imaging element and the lens. Further, since the lens portion is also configured to be directly attached to the ceramic substrate, the lens portion can be made thinner.
This is an example in which the chip is downsized (CSP and BGA) in the XY directions, and responds to the downsizing in the Z direction (height direction).
However, as described at the beginning, the demand for thin mobile phones and PDAs has demanded further downsizing of camera modules.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide a camera module and a camera module mounting device capable of realizing downsizing in the height direction by reducing the thickness of the lens component in the height direction while simplifying the focus adjustment. .
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a camera module according to the present invention includes: a camera module including an imaging lens system, an imaging device for forming an image of a subject from the imaging lens system, and a substrate that vertically holds the imaging device. The lens system includes at least one concave mirror and at least one reflecting mirror, and has a mirror lens system including a plurality of mirrors that fold an optical path of incident light, and the mirror lens system sequentially reflects the plurality of mirrors. To form an image on the image sensor.
The mirror lens system according to the present invention includes a mirror forming transparent body having a concave portion on one surface and a curved surface on the other surface, and a light reflecting layer on each of the concave bottom portion and the curved surface of the mirror forming transparent body. The concave mirror and the reflecting mirror are formed by forming
In the mirror lens system according to the present invention, the mirror lens system includes a lens holder, and the reflecting mirror and the concave mirror are arranged at a substantially central portion on an incident light side of the lens holder and a side facing the incident side, respectively. It is configured.
The reflecting mirror in the present invention can use a convex mirror.
According to a second aspect of the present invention, a position adjusting means for finely adjusting the position of the mirror lens system in the optical axis direction is provided.
The position adjusting means according to the present invention comprises a screw portion provided on an outer periphery of the mirror forming transparent body and an inner periphery of the lens holder, and a screw portion of the transparent body holder is screwed to a screw portion of the lens holder. The focus of the mirror lens system can be adjusted by finely adjusting the position of the mirror lens system in the optical axis direction.
According to a sixth aspect of the present invention, an anti-reflection coating process is performed on a threaded portion of the mirror forming transparent body.
According to the present invention, a refracting lens system is arranged between the mirror lens system and the image pickup device according to claim 1 or 3.
Further, a camera module mounting apparatus according to the present invention has the camera module mounted thereon.
[0009]
[Action]
According to the above configuration, the height of the optical system can be reduced by turning back the optical path of the incident light by the mirror configuration of the lens unit, and the size of the camera module can be reduced. Further, by providing a screw portion on the outer periphery of the mirror lens system and screwing it with the screw portion of the holder, focus adjustment can be simplified.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a first embodiment of a camera module according to the present invention.
As the substrate 8, a ceramic substrate or a resin substrate can be used, and a through hole 8a is provided in the center of the substrate.
A light receiving section 10 is formed at the center of the image sensor substrate, and an image sensor (bare chip) 9 is formed. The image sensor 9 is positioned on the lower surface of the substrate 8 such that the light receiving unit 10 faces the through hole 8a. Then, the pattern formed on the lower surface of the substrate 8 and the pattern of the image sensor substrate are electrically connected by bumps (gold bumps or solder bumps), and the space between the image sensor 9 and the lower surface of the substrate 8 is sealed by the underfill agent 12. You.
[0011]
After the image pickup device 9 is mounted on the lower surface of the substrate 8 by bare chip mounting using a flip chip, the transparent body holder 7 is mounted and fixed on the upper surface of the substrate 8.
The transparent body holder 7 has a columnar outer shape, a mirror lens system accommodating portion 7b for accommodating and holding a mirror lens system is formed inside, and a through hole 7a is continuously provided on the bottom surface of the mirror lens accommodating portion 7b. . A female screw 6 is formed on the inner wall of the mirror lens system housing 7b.
The mirror forming transparent body 2 has a substantially complementary shape to the mirror lens system housing portion 7b except for a central concave portion 2b, and is made of transparent plastic. On the side surface of the mirror forming transparent body 2, a male screw 5 for screwing with the female screw 6 of the transparent body holder 7 is formed. The periphery of the bottom surface is formed in a concave shape.
[0012]
On the other hand, a cylindrical concave portion 2c is provided at the center of the upper surface of the mirror forming transparent body 2, and the bottom surface is formed in a concave shape. A light reflecting layer is formed on the peripheral portion of the bottom surface of the mirror forming transparent body 2 and the bottom surface of the cylindrical concave portion 2c by a technique such as vacuum deposition, and a concave mirror (first mirror) 3 and a convex mirror (second mirror) 4 are formed. Is done.
After forming the convex mirror 4, a plate 2a of plastic resin or the like is fitted into the cylindrical concave portion 2c. Then, the surface on which the male screw 5 is formed of the mirror forming transparent body 2 is subjected to an antireflection coating treatment to form a mirror lens system.
[0013]
The mirror lens system can be attached to the transparent body holder 7 by screwing into the female screw 6 of the transparent body holder 7.
The light from the subject enters the mirror lens system, further enters the concave mirror 3 and is reflected, whereby the optical path is changed to the convex mirror 4 direction. The light incident on the convex mirror 4 is reflected and changed in the direction of the light receiving unit 10 of the image sensor 9, passes through the concave portion 2 b, and forms an image on the light receiving unit 10. Fine adjustment of the focus can be performed by rotating the mirror lens system and changing the distance between the mirror lens system and the light receiving unit 10.
Since the optical path length is folded, the thickness of the lens system can be reduced.
[0014]
In this embodiment, the case where the mirror lens is made of plastic has been described. However, the material is not limited to plastic as long as the material allows light to pass therethrough, such as a glass material. Further, as a method of forming the first mirror and the second mirror, a method different from vacuum deposition may be used. In addition, although the flip chip mounting method has been described, a bare chip mounting method using another method may be used.
[0015]
FIG. 2 is a sectional view showing a second embodiment of the camera module according to the present invention. In this embodiment, a mirror is directly attached to a lens holder to form a mirror lens system.
The substrate 8, the image sensor 9, the light receiving part 10, the bump 11, and the underfill agent 12 are the same functional parts as the parts with the same numbers in FIG.
The outer shape of the lens holder 17 is cylindrical, and a mirror housing portion 17b for housing and holding two mirrors is formed inside, and a through hole 17a is continuously provided on the bottom surface of the mirror housing portion 17b. A concave mirror 14, which is a first mirror, is arranged on the periphery of the bottom surface.
[0016]
On the other hand, on the upper surface of the lens holder 17, a mirror holding plate 18 having a mirror holding portion 18a at the center and including a transparent plate 18b at the periphery is attached.
The convex mirror 14, which is the second mirror, is attached to the lower surface of the mirror holding part 18a.
Light from the subject passes through the transparent plate 18b, enters the concave mirror 14 and is reflected, whereby the optical path is changed to the convex mirror 15 direction. The light that has entered the convex mirror 15 is reflected and changed in the direction of the light receiving unit 10 of the image sensor 9, passes through the through hole 17 a, and forms an image on the light receiving unit 10.
In order to slightly move the convex mirror 15 back and forth in the optical axis direction, for example, a female screw is provided on the inner wall of the lens holder 17 and a male screw is provided on the outer periphery of the mirror holding plate 18 so that the distance between the convex mirror 15 and the light receiving unit 10 is reduced. The focus can be fine-tuned by changing it. Since the optical path length is folded, the thickness of the lens system can be reduced.
[0017]
FIG. 3 is a sectional view showing a third embodiment of the camera module according to the present invention.
In this embodiment, a refracting lens system is provided in the lens system using the mirror shown in FIG.
At the center of the concave mirror 24, which is the first mirror, a refractive lens 26 including a convex lens 26a, a concave lens 26b, and a concave lens 26c is arranged.
A mirror holding plate 27 is arranged facing the concave mirror 24.
The mirror holding plate 27 has a mirror holding portion 27a at the center, and the periphery is constituted by a transparent plate 27b. The convex mirror 25 as the second mirror is attached to the lower surface of the mirror holding part 27a. At the image forming position, a CCD 28 as an image pickup device is arranged.
[0018]
Light from the subject passes through the transparent plate 27b, enters the concave mirror 24 and is reflected, whereby the optical path is changed to the convex mirror 25 direction. The light incident on the convex mirror 25 is reflected and changed in the direction of the refractive lens 26, passes through the refractive lens 26, and forms an image on the surface of the CCD 28.
When a fixed-focus optical system is configured, a screw is provided on the outer peripheral portion of the lens frame of a part of the refraction lens 26, and a part of the lens is configured to be movable back and forth in the optical axis direction. The focus can be finely adjusted by changing the distance to the focal point. When a zooming optical system is configured, a sliding mechanism that can move back and forth in the optical axis direction is provided on a lens frame of a part of the refracting lens 26, and a part of the lens is moved by the sliding mechanism during photographing. The zooming can be performed by moving. Also in this embodiment, since the optical path is folded, the thickness of the lens system can be reduced despite the partial use of the refractive lens system.
[0019]
FIG. 4 is a sectional view showing a fourth embodiment of the camera module according to the present invention.
This embodiment is an example in which an image sensor module is housed in a lens holder.
A chip of a resistor R, a capacitor C, and a semiconductor element _Tc is mounted on the lower surface of the substrate 40, and is electrically connected to a pattern (not shown) by soldering. An image sensor 41 having a light receiving portion 38 at the center is mounted on the upper surface of the substrate 40, and is electrically connected to a pattern (not shown) by a bump (gold bump or solder bump) 39.
[0020]
A lens holder 37 provided with a mirror is mounted on the substrate 40 having the above configuration so as to accommodate the image sensor module.
The lens holder 37 has a cylindrical outer shape, a mirror housing portion 37b for housing and holding two mirrors is formed inside, and a through hole 37a for housing the image sensor module is continuously provided on the bottom surface of the mirror housing portion 37b. I have.
A concave mirror 34, which is a first mirror, is arranged on the periphery of the bottom surface of the lens holder 37. The mirror holding plate 18 has a mirror holding portion 36a at the center on the upper surface of the lens holder 37, and the periphery is a transparent plate 36b. The configuration in which the convex mirror 35 as the second mirror is attached to the lower surface is the same as the optical system using the mirror in FIG.
[0021]
The optical path of the light from the subject is also reflected and reflected by the concave mirror 34 and the convex mirror 35 and forms an image on the light receiving section 38 of the image sensor module as in FIG.
In order to slightly move the convex mirror 35 back and forth in the optical axis direction, for example, a female screw is provided on the inner wall of the lens holder 37, and a male screw is provided on the outer periphery of the mirror holding plate 36 to change the distance between the convex mirror 35 and the light receiving unit 38. Thereby, the focus can be finely adjusted. Since the optical path length is folded, the thickness of the lens system can be reduced.
[0022]
FIG. 5 is a schematic diagram showing an example in which the camera module according to the present invention is used in a mobile phone.
The board 43 of the camera module 42 according to the present invention is connected to one end of the flexible board 44, and the connector (male) 45 is connected to the other end. A connector (female) 46 is provided inside the mobile phone 47. By plugging the connector 45 into 46, it is connected to the electronic circuit of the mobile phone 47.
Since the camera module 42 according to the present invention is thinner than the conventional one, the mobile phone can be further thinned.
[0023]
The camera module according to the present invention can be applied to a digital camera, a vehicle-mounted camera, a board camera for a computer, a surveillance camera, a door horn camera, and the like, in addition to a portable communication device such as a mobile phone and an information terminal device such as a PDA.
[0024]
As described above, with the mirror configuration of the lens unit, the optical path length of the incident light can be turned back and the thickness of the optical system can be reduced, so that the camera module can be further reduced in size. Further, by providing a screw portion on the outer periphery of the mirror lens system or the outer periphery of the mounting frame of the second mirror and screwing the screw portion with the screw portion of the holder, the focus adjustment can be easily performed without trouble.
[0025]
【The invention's effect】
According to the present invention, the size of the camera module can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a first embodiment of a camera module according to the present invention.
FIG. 2 is a cross-sectional view showing a second embodiment of the camera module according to the present invention.
FIG. 3 is a cross-sectional view showing a third embodiment of the camera module according to the present invention.
FIG. 4 is a sectional view showing a fourth embodiment of the camera module according to the present invention.
FIG. 5 is a schematic view showing an example in which a camera module according to the present invention is used in a mobile phone.
FIG. 6 is a cross-sectional view illustrating an example of a conventional camera module.
FIG. 7 is a sectional view showing an example of another proposed camera module.
[Explanation of symbols]
1, 13, 23, 33, 42 Camera module 2 Transparent body for mirror formation 3, 14, 24, 34 Concave mirror (first mirror)
4,15,25,35 convex mirror (second mirror)
5 Male screw 6 Female screw 7 Transparent body holder 8, 40, 43 Substrate 9, 41 Image sensor 10, 20, 38 Light receiving unit 11, 21, 39 Bump 12 Underfill agent 16 Translucent plate 17, 37 Lens holder 18, 27 , 36 Mirror holding plate 26 Refraction lens 28 CCD
44 Flexible board 45 Connector (male)
46 Connector (Female)
47 mobile phone

Claims (9)

In a camera module comprising an imaging lens system, an imaging device for forming a subject image from the imaging lens system, and a substrate holding the imaging device up and down,
The imaging lens system includes a mirror lens system including a plurality of mirrors including at least one concave mirror and at least one reflecting mirror, and folding back an optical path of incident light,
The camera module according to claim 1, wherein the mirror lens system sequentially reflects the plurality of mirrors to form an image on the image sensor. The mirror lens system includes a mirror forming transparent body having a concave portion on one surface and a curved surface on the other surface, and forming a light reflecting layer on the concave bottom portion and the curved surface of the mirror forming transparent member, respectively. 2. The camera module according to claim 1, wherein the concave mirror and the reflecting mirror are configured. The mirror lens system comprises a lens holder, wherein the reflecting mirror and the concave mirror are arranged at a substantially central portion on an incident light side of the lens holder and on a side facing the incident side, respectively. 2. The camera module according to 1. The camera module according to claim 2, wherein the reflecting mirror is a convex mirror. 3. The camera module according to claim 2, further comprising a position adjusting means for finely adjusting the position of the mirror lens system in the optical axis direction. The position adjusting means comprises a screw portion provided on an outer periphery of the mirror forming transparent body and an inner periphery of the lens holder, and a screw portion of the transparent body holder is screwed to a screw portion of the lens holder. 6. The camera module according to claim 5, wherein the focus of the mirror lens system can be adjusted by finely adjusting the position of the mirror lens system in the optical axis direction. 7. The camera module according to claim 6, wherein an anti-reflection coating process is performed on a threaded portion of the transparent body for mirror formation. The camera module according to claim 1, wherein a refraction lens system is disposed between the mirror lens system and the image sensor. A camera module mounting device using the camera module.

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