JP2002182270A - Camera module and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera module which can be made smaller in size and thinner in shape by improving the structure of the camera module. SOLUTION: As for the structure of the camera module, a filter part 18 provided with IR cutting characteristics and used also as a diaphragm is arranged in front of a lens 11. That is, the module is provided with the lens 11, the filter part 18 disposed in front of the lens 11, a 1st holder 13 for holding the lens 11 and the filter part 18, a 2nd holder 15A as a lens barrel for holding the 1st holder 13, and a substrate 17 on which an imaging device 16 is fixed, and the 1st holder 13 with the lens 11 and the filter part 18 previously formed into one body is assembled into the 2nd holder 15A, thereafter, the 2nd holder 15A is fixed on the substrate 17 equipped with the imaging device. An IR cutting filter is not arranged between the lens 11 and the imaging device 16, so that the thickness H1 of the module is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a camera module used for a portable terminal or the like.

[0002]

2. Description of the Related Art In recent years, digital networks and mobile devices have been developed, and information portable terminals as multimedia tools have been developed.

In addition to the conventional CCD camera module, a CMOS camera module excellent in power saving and space saving has been developed, and is expected to be applied to various uses according to new ideas and needs.

FIG. 2 is a sectional view of a basic structure of a camera module used for a portable terminal or the like. The camera module 10 includes a lens 11, an aperture stop tube 12 disposed in front of the lens 11, a lens 11 and an aperture stop tube 12.
, A cylindrical first holder 13, an IR (infrared ray abbreviation, infrared light) cut filter 14 for removing infrared light, and a second holder 15 of a lens barrel for holding all of them. And a substrate 17 to which an image pickup device 16 is fixed.
a, the second holder 15 is fixed to the substrate 17 with the image sensor, and then the second holder 15
A first holder 13 to which a lens 11 and an aperture stop tube 12 are attached in advance is attached to the tip end of the lens.
The aperture stop tube 12 has a conical stop hole 12a for forming an image field.

It is important to reduce the thickness (thinness) of the camera module as described above by reducing the thickness H from the upper surface of the image sensor 16 to the tip of the holder 15. The thickness H is generally determined by the size of the image sensor 16 and the lens position determined by the required field of view, the thickness of the aperture stop tube 12 also serving as an aperture, and the IR cut for removing infrared light harmful to a color image. It is determined by the thickness of the filter 14.

As an IR cut filter for removing infrared light harmful to a color image, a filter dedicated to IR cut or a filter having an IR cut deposited film formed on a glass surface is usually used. However, since the IR cut filter has a refractive index τ and the thickness is t, the optical path length of the lens is extended by t × (1-1 / τ), so that the thickness of the camera module increases accordingly. become. Also, if the image sensor is downsized or the focal length of the lens is short,
Since the dimensions from the image sensor to the lens are restricted, the structure in which the IR cut filter is inserted is restricted in the conventional structure.

Further, since the IR cut filter having the refractive index is provided between the lens and the image sensor, the dimensional accuracy of the distance must be very high. Further, reflected light may be generated inside the holder by the IR cut filter, which may affect the image.

On the other hand, Japanese Patent Application Laid-Open No. Hei 9-304691 discloses a camera in which a deflecting member is disposed between a predetermined focal plane and an optical system so that a light beam from an object passing outside the optical axis of the optical system is transmitted to the optical axis. There is disclosed a focus detection device that deflects to the side to reduce the size of the focus detection optical system and that can change the focus detection area even when the focus detection optical system is integrally formed into a module. However, there is a disadvantage that the number of members is increased because a new deflecting member is arranged. Further, the structure is basically different from that of a camera module in which an image pickup optical system (including an IR cut filter) is arranged on a substrate as shown in FIG. It did not solve the problem.

[0009]

As described above, in the conventional structure in which the IR cut filter is disposed between the lens and the image pickup device, the thickness of the module increases because the IR cut filter has a refractive index τ. become. Also, if the image sensor is downsized or the focal length of the lens is short,
There is no dimensional margin between the image sensor and the lens, and there is a restriction in inserting the IR cut filter. In addition, in order to dispose the IR cut filter between the lens and the image sensor, the dimensional accuracy of the distance must be very high.
Reflected light was generated inside the holder by the R-cut filter, which sometimes affected the image.

In view of the above problems, it is an object of the present invention to review a camera module structure and provide a camera module that can be reduced in size and thickness.

[0011]

According to a first aspect of the present invention, there is provided a camera module comprising: a lens; a filter disposed on a front surface of the lens and having an IR cut characteristic and a diaphragm; the lens and the filter; A first holder for holding the unit, a second holder having a substantially lens barrel structure for holding the first holder, and the second holder;
A substrate to which the image sensor is fixed.

In the camera module of the present invention, in the structure, a filter section having a structure having IR cut characteristics and also having an aperture is disposed on the front surface of the lens. As a result, there is no component having a refractive index between the lens and the image sensor, so that the camera module can be made thinner and the dimensional tolerance can be reduced.

By arranging a filter portion having an IR cut characteristic required for a color camera on the front surface of the lens,
The influence of the reflected light generated inside the second holder can be prevented,
In addition, since the filter section having the IR cut characteristic also has the aperture function, cost reduction including reduction in the number of parts can be achieved. Also, there is an advantage that dust does not enter the lens surface without having a stop hole unlike a conventional aperture stop tube.

According to a second aspect of the present invention, in the camera module of the first aspect, the filter section includes an IR cut filter for removing infrared light, a field light shielding film disposed on a front surface of the IR cut filter, and the IR cut filter. A stop light-shielding film disposed on the rear surface of the cut filter.

According to the present invention, the visual field light shielding film and the diaphragm light shielding film may be formed on the front and rear surfaces of the IR cut filter in the form of a film, respectively, and the filter portion having the diaphragm can be formed relatively easily.

According to a third aspect of the present invention, in the camera module according to the first or second aspect, the size of a light-transmitting region formed at the center of the front surface of the IR cut filter by the field light-shielding film, and the size of the IR cut filter by the aperture light-shielding film. An image field is formed by the size of the light-transmitting region formed at the center of the rear surface.

According to the present invention, a desired field of view can be formed relatively easily by forming the size of each light projecting area of the film-shaped field light shielding film and the aperture light shielding film on the front and rear surfaces of the IR cut filter. .

According to a fourth aspect of the present invention, in the camera module according to any one of the first to third aspects, the first holder is screwed into the lens barrel of the second holder so as to be movable back and forth. The lens position can be adjusted with respect to an image sensor by moving the first holder back and forth in a state where the second holder is mounted on the substrate.

According to the present invention, the I holder is provided inside the second holder.
Since the R-cut filter is not provided, the adjustment distance for moving the first holder back and forth in the second holder can have a degree of freedom, and thus the degree of freedom of the focus adjustment can be increased.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a camera module, comprising: a first step of manufacturing a substrate with an image sensor by fixing the image sensor to the substrate; a lens; A second step of integrally assembling a filter section having a cut characteristic and a structure having a function of a stop using a first holder, and a first step in the second step.
A third step of incorporating the assembly integrally formed by the holder into the distal end side of a second holder having a substantially lens barrel structure, and integrally integrating the second holder in the third step. And a fourth step of fixing the obtained substrate to the substrate with an image sensor produced in the first step.

In the method of manufacturing a camera module according to the present invention, the lens and the filter portion having the IR cut characteristics and the aperture function are assembled to the first holder. The step of attaching to the holder can be omitted.

Further, the lens and the filter unit, which are integrally assembled by the first holder in the second step, are:
After being mounted on the distal end side of the second holder having a substantially lens barrel structure, the one integrated with the second holder is fixed to the substrate with the image sensor to which the image sensor is fixed. After assembling only the cylindrical second holder with respect to the substrate with the imaging element, incorporating the first holder, the lens, and the filter unit integrally assembled with the second holder. Compared with this, the time during which the light receiving surface of the image sensor directly contacts the outside air can be shortened, and the light receiving surface of the image sensor can be protected from dust.

According to a sixth aspect of the present invention, in the method for manufacturing a camera module according to the fifth aspect, in the third step, the first holder is screwed into the lens barrel of the second holder so as to be movable back and forth. In the fourth step, after the second holder is fixed to the substrate with the imaging element, the lens position is moved with respect to the imaging element by further moving the first holder back and forth. Focus adjustment.

In the present invention, a focus adjustment step is added to the fourth step. Since the IR cut filter is not arranged inside the second holder, there is a degree of freedom in moving the first holder back and forth in the second holder, and therefore, the degree of freedom of focus adjustment can be increased. Can be.

[0025]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a camera module according to an embodiment of the present invention. The same parts as those in FIG.

In FIG. 1, the camera module 10A
Is disposed on the front surface of the lens 11 and the
A filter section 18 having a cut characteristic and a diaphragm function, a cylindrical first holder 13 for holding the lens 11 and the filter section 18, and a lens barrel for holding the first holder 13; Second holder 15A and image sensor 16
And a substrate 17 on which the lens 11 and the filter section 18 are integrated in advance by the first holder 13 and incorporated into a second holder 15A. It has a structure in which it is fixed on a substrate 17 with elements with an adhesive or the like.

The filter section 18 has an IR cut filter 14 having a predetermined thickness for removing infrared light, and the front face of the IR cut filter 14 except for the central light transmitting area S1. The light-blocking film 14 in the light-blocking region
The aperture stop light-shielding film 14b is formed on the rear surface of the IR cut filter 14 in the light-shielding area except for the central light-transmitting area, that is, the exposure area S2 (S1> S2). The field of view is determined by the size of the light-transmitting region S1 of the field light-shielding film 14a and the size of the light-transmitting region S2 of the stop light-shielding film 14b. The field light-shielding film 14a and the aperture light-shielding film 14b can be formed of a film-like light-absorbing black film.

The second holder 15A has a smaller height (thickness) than the holder 15 shown in the conventional example of FIG. 2, and has a ring-like shape formed on the holder 15 for mounting the IR cut filter 14. Since the ribs 15a are not required, there is an advantage that a simple tubular shape is sufficient and molding is easy. The thickness H1 from the upper surface of the imaging element 16 to the tip of the holder 15 is clearly smaller than the thickness H in the conventional example shown in FIG. 2, and can be reduced to 2/3 or less.

Further, an inner thread is formed on the inner peripheral surface of the distal end side (upper side in the figure) of the second holder 15A.
An outer screw is formed on the outer peripheral surface of the third screw so as to be screwed with the inner screw. Thus, the first holder 13 can be fitted and mounted in the second holder 15A, and the first holder 13 can be moved back and forth in the direction of the lens optical axis to focus the lens position on the light receiving surface of the image sensor 16. Can be adjusted.

Next, an example of a method of manufacturing the camera module 10A will be described. The substrate 17 with an image sensor is manufactured by fixing the image sensor 16 to the substrate 16 in advance. Then, the lens 11 and the filter portion 18 provided on the front surface of the lens 11 and having the IR cut characteristic and the aperture function are integrally assembled using the first holder 13.

The unit integrally assembled with the first holder 13 is incorporated into the inner periphery of the distal end in the second holder 15A which is a lens barrel. In this case, it can be incorporated by screwing an external thread on the outer periphery of the first holder 13 to an internal thread cut on the distal end side in the second holder 15A. In this state, the first holder 13 is the second holder 1
It is screwed into the 5A lens barrel so as to be able to move back and forth.

Next, the second holder 15A
Is fixed to the substrate 17 with the imaging element manufactured as described above using a fixing means such as an adhesive.

Further, by moving the first holder 13 in the second holder 15A back and forth in a state where the second holder 15A is mounted on the substrate 17 with the imaging element, the lens 11 is The focus position can be adjusted with respect to the light receiving surface. After the focus adjustment, the first
The holder 13 is positioned and fixed in the second holder 15A using an adhesive or the like.

According to the embodiment of the present invention described above,
In the structure of the camera module, the filter section 18 having an IR cut characteristic and also having a diaphragm is disposed on the front surface of the lens 11, so that the lens 11 and the image sensor 16 are arranged.
Eliminating the part (14) having a refractive index between the two allows the camera module to be thinner. Also, the lens 11
By eliminating the member between the lens 11 and the image sensor 16, the lens 11
The distance to the image sensor 16 is shortened, and the dimensional tolerance when positioning the lens can be reduced.

Further, IR necessary for a color camera
By arranging the filter unit 18 having a cut characteristic on the front surface of the lens 11, it is possible to prevent the influence of the reflected light generated inside the conventional lens 11 and the image pickup device 16 and to provide the filter unit 18 having the IR cut characteristic. With the aperture function, the cost can be reduced including the number of parts. Further, a structure that does not have the aperture hole 12a (see FIG. 2) unlike a conventional aperture stop tube can also prevent dust from entering the lens surface or the imaging element surface. Further, since the IR cut filter is not arranged inside the second holder 15A, the first holder 13 is connected to the second holder 1A.
It is also possible to widen the adjustment range when performing focus adjustment by moving back and forth within 5A.

[0036]

As described above, according to the present invention, it is possible to further reduce the size and thickness of the camera module while maintaining the imaging performance of the camera module.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a camera module according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a conventional camera module.

[Explanation of symbols]

 Reference Signs List 10A: Camera module 11: Lens 13: First holder 14: IR cut filter 14a: Field-of-view light-shielding film 14b: Aperture light-shielding film 15A: Second holder (barrel) 16: Image sensor 17: Substrate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/335 H04N 5/335 VF term (Reference) 2H044 AA11 AA19 AC01 AE06 AG01 2H054 AA01 2H083 AA04 AA26 AA52 AA53 5C024 AX01 CY48 EX51 GY01 GY31

Claims (6)

[Claims] 1. A lens, a filter disposed on a front surface of the lens and having an IR cut characteristic and an aperture, a first holder for holding the lens and the filter, and a first holder. A camera module, comprising: a second holder having a substantially lens barrel structure for holding a holder; and a substrate to which the second holder is attached and to which an image sensor is fixed. 2. The filter section comprises: an IR cut filter for removing infrared light; a field light shielding film disposed on a front surface of the IR cut filter; and an aperture light shielding film disposed on a rear surface of the IR cut filter. The camera module according to claim 1, wherein the camera module is provided. 3. The field of view depends on the size of a light-transmitting region formed in the center of the front surface of the IR cut filter by the field light-shielding film and the size of the light-transmitting region formed in the center of the rear surface of the IR cut filter by the stop light-shielding film. 3. The camera module according to claim 1, wherein 4. The first holder is screwed and assembled into a lens barrel of the second holder so as to be movable back and forth, and the first holder is assembled with the second holder mounted on a substrate. Moving the lens back and forth to adjust the focus of the lens position with respect to the image pickup device.
A camera module according to any one of the above. 5. A first step of manufacturing a substrate with an image sensor by fixing the image sensor to a substrate; and a lens and a structure provided on the front surface of the lens and having an IR cut characteristic and also having an aperture. The filter section,
A second step of integrally assembling with the use of the holder, and a step of integrally assembling with the first holder in the second step on the distal end side of the second holder having a substantially lens barrel structure. A third step of assembling, and a fourth step of fixing the one integrated with the second holder in the third step to the substrate with the imaging element manufactured in the first step. A method for manufacturing a camera module, comprising: 6. In the third step, the first holder is screwed into the lens barrel of the second holder so as to be movable back and forth, and in the fourth step, the second holder is mounted on the second holder. 6. The camera module according to claim 5, wherein, after the holder is fixed to the substrate with the image sensor, the first holder is further moved back and forth to adjust the focus of the lens position with respect to the image sensor. Manufacturing method.