JP2001111873A - Image pickup device and camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of an image noise due to incidence of an unwanted light in realizing miniaturization and low profile of the image pickup device. SOLUTION: The image pickup device is provided with a board 6 that has a light transmission through-hole 9 on an inner wall face 9A on which a reflection prevention layer 15 is provided and with an image pickup element 7 that is mounted on a lower face 6A of the board 6 in a state that an image pickup section 10 is exposed from the through-hole 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus having an image pickup device and a camera system using the same.
This is suitable for use in realizing a small and thin imaging device.

[0002]

2. Description of the Related Art In recent years, a camera system equipped with an imaging device has been required to be used in a small information terminal such as a personal computer or a portable videophone. Demands for thinning are increasing.

Conventionally, as an image pickup apparatus using an image pickup device such as a CCD image pickup device, the one shown in FIG. 13 is widely known. In the illustrated imaging device 51, a QFP (Quad Flat P) formed by mounting a chip-shaped imaging device 52 on a package 53 and hermetically sealing with a seal glass 54.
ackage) type structure. Image sensor 52
Is fixed to the bottom of the concave portion of the package body 53 using a die bond material (not shown), and electrically connected to a lead terminal (not shown) for external connection via a bonding wire (not shown) such as a gold wire. The space for the connection is secured in the interior (hollow portion) of the package 53. A lens unit (not shown) is mounted on the seal glass 54 of the package 53.

[0004]

In the above-mentioned conventional image pickup apparatus 51, if a lens unit (not shown) mounted on the image pickup apparatus 51 is included, the image pickup apparatus 51 has a considerable thickness and a large overall plane size. The above-mentioned requirements for miniaturization and thinning could not be sufficiently satisfied. In addition, the thickness of each of the components (the image sensor 52, the package 53, and the seal glass 54) has reached a limit in reducing the thickness.

Therefore, the present applicant has already proposed an imaging device 61 having a configuration as shown in FIG. The illustrated imaging device 61 mainly includes a substrate 62, an imaging element 63, and a lens unit 64. The substrate 62 has through holes 6 for light transmission.
The imaging device 63 is mounted on the lower surface 62A of the substrate 62 in a state where the imaging unit 66 is exposed from the through hole 65. The lens unit 64 is mounted on the upper surface 62B of the substrate 62 using an adhesive or the like.

In the image pickup device 61 having the above-described structure, the image pickup device 63 is directly attached to the substrate 62 in a bare chip state, so that the package size for hermetically sealing the image pickup device 63 is reduced and , Substrate 62
And the imaging element 63 are densely arranged in the thickness direction. Therefore, the thickness of the entire imaging device 61 can be reduced, and the planar size can also be reduced.

However, the image pickup device 61 shown in FIG.
In order to realize a small and thin device as a whole, the through hole 65 of the substrate 62 and the imaging unit 66 of the imaging element 63
Are set substantially equal to each other so that the inner wall surface 65 of the through-hole 65 near the imaging unit 66 is set.
A has a vertically upright structure. Therefore, part of the light incident through the lens unit 64 is
When the light hits the inner wall surface 65A, there is a problem that the light reflected therefrom easily enters the imaging unit 66 and easily induces image noise such as flare and ghost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to effectively reduce the generation of image noise due to the incidence of unnecessary light when realizing a small and thin imaging device. Is to prevent it.

[0009]

In the image pickup apparatus of the present invention, a through hole for light transmission is provided, and an antireflection layer is provided on the inner wall surface of the through hole. And an image pickup device mounted on one surface of the substrate in a state where is exposed. The camera system according to the present invention uses the imaging device having the above-described configuration.

[0010] According to the imaging apparatus having such a configuration and the camera system using the same, by providing the anti-reflection layer on the inner wall surface of the through hole, the reflection of light on the inner wall surface of the through hole is prevented by the anti-reflection layer. Or reduction), thereby making it possible to effectively prevent unnecessary light from entering the imaging unit.

In another imaging apparatus according to the present invention, a through-hole for light transmission is provided, and an inner wall surface of the through-hole is formed to be inclined at a predetermined angle. And an image pickup device mounted on one surface of the substrate in a state where is exposed. In another camera system according to the present invention, the imaging device having the above-described configuration is used.

According to the imaging apparatus having the above configuration and the camera system using the same, by inclining the inner wall surface of the through hole at a predetermined angle, light incident on the inner wall surface of the through hole is directed in a direction different from that of the imaging unit. By reflecting the light, it is possible to effectively prevent unnecessary light from entering the imaging unit.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram schematically showing the overall configuration of a camera system according to the present invention. The illustrated camera system 1 includes an imaging device 2 having an imaging function, a signal processing unit 3 that performs various processing (for example, image compression processing, etc.) on an image signal obtained by the imaging device 2, and a signal processing unit 3 And a power supply unit 5 for supplying power to these functional units.

FIG. 2 is a side sectional view showing the structure of the image pickup apparatus according to the first embodiment of the present invention. Illustrated imaging device 2
Is mainly composed of a substrate 6, an image sensor 7 and a lens unit 8. The substrate 6 has a structure in which, for example, a metal plate made of stainless steel and a flexible wiring substrate based on a polyimide film are bonded together with an adhesive or the like (not shown). (Not shown) is formed. The substrate 6 is provided with a through hole 9 for light transmission. As shown in FIG. 3, the through hole 9 is formed in a quadrangular (rectangular) shape having substantially the same size as the imaging unit 10 of the imaging device 7.

The structure, material and the like of the substrate 6 are as follows.
The present invention is not limited to the above-described combination of the metal plate and the flexible substrate. For example, all or a part of the substrate 10 may be formed of a polyimide organic material, a glass epoxy organic material, or a ceramic material, a glass material, or the like. Even so. However, no matter which substrate structure is adopted, it is necessary to have a wiring pattern for electrical connection with the image sensor 7.

The image sensor 7 is, for example, a CCD image sensor, C
It is composed of a MOS image pickup device or the like, and an image pickup section 10 is provided on its main surface. In the imaging unit 10, a number of pixels having a photoelectric conversion function are two-dimensionally arranged. Further, a plurality of electrode portions (not shown) made of, for example, aluminum pads are formed on the periphery of the image sensor 7 so as to surround the image capturing section 10. The image pickup device 7 is mounted (directly attached) in a bare chip state on the lower surface 6A of the substrate 6 by a flip chip method or the like.
(Not shown) and the wiring pattern of the substrate 6 (not shown)
And are electrically connected. In this mounted state, the image pickup unit 10 of the image pickup device 7 is arranged so as to be exposed from the through hole 9 of the substrate 6.

The mounting structure of the image sensor 7 on the substrate 6 is not limited to the flip-chip type described above, but may be a device using an anisotropic conductive material, such as one using an anisotropic conductive material. Then, any mounting structure may be adopted.

The lens unit 8 is mounted on the upper surface 6B of the substrate 10 using, for example, an unillustrated adhesive or a holder member so as to cover a space above the imaging section 10 of the imaging element 7. The lens unit 8 includes the lens barrel 1
1, the optical filter 12 and the lens 13. A stop 11A for regulating incident light is integrally formed at the tip of the lens barrel 11. As the optical filter 12, for example, a so-called infrared cut filter that has a function of cutting infrared light from incident light that enters through the above-described diaphragm 11A is used. This optical filter 1
Reference numeral 2 is fitted and fixed near the distal end of the lens barrel 11 in the vicinity of the stop 11A. The lens 13 is connected to the aperture 11
This is for causing the light incident through the A and the optical filter 12 to form an image in the imaging unit 10 of the imaging element 7. The lens 13 is fixed to the inside of the lens barrel 11 using an adhesive 14 in a state where the lens 13 is positioned with reference to the aperture portion 11A.

In the imaging device 2 having the above configuration,
Light that has entered through the optical filter 12 from the distal end portion (aperture portion 11A) of the lens barrel 11 of the lens unit 8
Is imaged on the image pickup unit 10 of the image pickup device 7 by the refraction effect of At this time, the light emitted from the lens 13 is
Is incident on the imaging unit 10 through the opening 9. An image signal received by the image pickup unit 10 of the image pickup device 7 and obtained by photoelectric conversion there is sent to the signal processing unit 3 (see FIG. 1) via a wiring pattern of the substrate 6 (flexible wiring substrate). .

Here, the feature of the first embodiment is that the antireflection layer 15 is provided on the inner wall surface 9A of the through hole 9 of the substrate 6.
Is provided. The anti-reflection layer 15 is formed by subjecting the inner wall surface 9A of the through hole 9 of the substrate 6 to a roughening process by, for example, blasting or plating, or a blackening process by black coating or thin film formation. It is.

Among them, in the case of the anti-reflection layer 15 formed by the surface roughening treatment, as shown in FIG.
When light is incident on the inner wall surface 9A, reflection of the light on the inner wall surface 9A is reduced in such a manner that the incident light is dispersed in multiple directions by the antireflection layer 15. Thereby, of the light incident on the inner wall surface 9A of the through hole 9, only a part of the light that is dispersed by the anti-reflection layer 15 and whose intensity is weakened by the dispersion is incident on the imaging unit 10 of the imaging element 7. become. Accordingly, the amount of unnecessary light incident on the imaging unit 10 is reduced, and the intensity of light incident on each point of the imaging unit 10 is extremely small. As a result, it is possible to effectively prevent the incidence of unnecessary light on the imaging unit 10 and the occurrence of image noise (flares, ghosts, and the like) due to this.

On the other hand, in the case of the antireflection layer 15 formed by the blackening process, when light enters the inner wall surface 9A of the through hole 9, the incident light is absorbed by the antireflection layer 15. Thereby, reflection of light on the inner wall surface 9 </ b> A of the through hole 9 can be prevented, and incidence of unnecessary light on the imaging unit 10 can be prevented. As a result, it is possible to effectively prevent unnecessary light from being incident on the imaging unit 10 and the occurrence of image noise due to this.

Further, in the case of the anti-reflection layer 15 formed by using both the above-mentioned roughening treatment and blackening treatment, when light enters the inner wall surface 9A of the through hole 9, the incident light is reflected by the anti-reflection layer. The light that has been absorbed by the antireflection layer 15 is dispersed in multiple directions by the antireflection layer 15. This makes it possible to more reliably prevent unnecessary light from entering the imaging unit 10.

FIG. 5 is a sectional view of an essential part for explaining an application example of the image pickup apparatus according to the first embodiment. In this application example, an antireflection layer 15 is provided not only on the inner wall surface 9A of the through hole 9 of the substrate 6 but also on the upper surface 6B of the substrate 6 on the light incident side. The anti-reflection layer 15 is formed in the through hole 9 of the substrate 6.
Is formed continuously from the inner wall surface 9A to the substrate upper surface 6B.

By providing the anti-reflection layer 15 also on the upper surface 6B of the substrate 6, the light absorption function and the light dispersion function of the anti-reflection layer 15 described above allow the upper surface 6B of the substrate 6 to be formed.
Can be prevented (or reduced) from being reflected on the light incident on the surface. Accordingly, it is possible to effectively prevent the light that has entered and reflected on the upper surface 6B of the substrate 6 from being irregularly reflected in the above-described lens unit 8 and being incident on the imaging unit 10 of the imaging element 7. As a result, the incidence of unnecessary light on the imaging 10 can be more reliably prevented.

FIG. 6 is a side sectional view showing the structure of an image pickup apparatus according to a second embodiment of the present invention. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and overlapping description will be omitted.

In the imaging device 2 according to the second embodiment, the inner wall surface 9A of the through hole 9 provided in the substrate 6 has a hole diameter gradually increasing from the lower surface 6A of the substrate 6 toward the upper surface 6B. It is formed so as to be inclined. Inner wall 9
The inclination angle of A is incident on the inner wall surface 9A and the inner wall surface 9A.
The condition is set so that the light reflected by A does not enter the imaging unit 10 of the imaging device 7.

Here, specific conditions for setting the inclination angle of the inner wall surface 9A will be described with reference to FIGS. 7 (a) and 7 (b). FIG. 7A is a schematic diagram when the inner wall surface 9A of the through hole 9 is perpendicular to the imaging unit 10.
(B) is a schematic diagram when the inner wall surface 9A of the through hole 9 is inclined at an angle δ with respect to the imaging unit 10.

Now, let us consider a case where a light beam incident through the imaging optical system such as the lens unit 8 forms an angle θ with respect to a plane perpendicular to the imaging unit 10.
The incident angle β and the reflection angle β of the light beam in (b) are represented by β = π / 2−θ with respect to a normal line indicated by a broken line in the drawing. At this time, the inner wall surface 9A of the through hole 9 is made vertical or
Depending on whether or not A has an inclination, the traveling direction of the light ray reflected on the inner wall surface 9A (the direction in which the light is reflected) differs even for the light rays incident at the same angle θ.

Here, in FIG. 7B, the imaging unit 10
If the angle of the inner wall surface 9A with respect to a plane perpendicular to
+ Θ + β = π / 2, and when this is deformed, α = π / 2−θ−β (1)

The condition that the axis of the light reflected by the inner wall surface 9A is parallel to the imaging unit 10, that is, the condition that the light beam reflected by the inner wall surface 9A is not incident on the imaging unit 10, is θ + β + β = π
.Beta. = (. Pi./2-.theta.)/2 (2)

Then, substituting equation (2) into equation (1), α = π / 2−θ− (π / 2−θ) / 2 = π / 2−θ−π / 4 + θ / 2 = π / 4-θ / 2 = (π / 2−θ) / 2 (3)

Since the inclination angle δ of the inner wall surface 9A in FIG. 7B is represented by δ = π / 2−α, substituting the above equation (3) into: π = π / 2− (π / 2−θ) / 2 = π / 4−θ / 2.

From the above, the inclination angle δ of the inner wall surface 9A
May be set so as to satisfy the condition of δ ≦ (π / 2−θ) / 2 (4). Specifically, for example, if the angle θ is 30 °, the inner wall surface 9A may be formed to be inclined under the condition of δ ≦ 30 °.

As described above, the inner wall surface 9A of the through hole 9 of the substrate 6
8, light incident on the inner wall surface 9A can be reflected in a direction different from that of the imaging unit 10, that is, in a direction not incident on the imaging unit 10, as shown in FIG. Accordingly, it is possible to effectively prevent the incidence of unnecessary light on the imaging unit 10 and the occurrence of image noise associated therewith.

FIG. 9 is a side sectional view showing the structure of an image pickup apparatus according to a third embodiment of the present invention. In the third embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and overlapping description will be omitted.

In the image pickup device 2 according to the third embodiment, the inner wall surface 9A of the through hole 9 of the substrate 6 is formed in the same inclined state as in the second embodiment, and the inner wall surface 9A and the And an anti-reflection layer 15 similar to that of the first embodiment is provided on the upper surface 6B of the substrate subsequent to the first embodiment. That is, the imaging device 2 according to the third embodiment includes
This is a combination of the features of the second embodiment. However, as a combination example of the first and second embodiments, a configuration in which the antireflection layer 15 is provided only on the inner wall surface 9A of the through hole 9 in FIG.

By adopting such a structure, for example, when the antireflection layer 15 is formed by a roughening process, light is incident on the inner wall surface 9A of the through hole 9 as shown in FIG. In this case, the incident light is dispersed in multiple directions by the anti-reflection layer 15 and the light dispersed by the anti-reflection layer 15 is dispersed by the inclination of the inner wall surface 9A.
Is difficult to be incident on the imaging unit 10. This makes it possible to significantly reduce the amount of unnecessary light incident on the imaging unit 10 as compared with the first embodiment.

On the other hand, when the anti-reflection layer 15 is formed by a blackening process, when light enters the inner wall surface 9A of the through hole 9, the incident light is absorbed by the anti-reflection layer 15, and Therefore, the light that has not been absorbed is reflected in a direction different from that of the imaging unit 10 due to the inclination of the inner wall surface 9A. This makes it possible to significantly reduce the amount of unnecessary light incident on the imaging unit 10 as compared with the first embodiment.

Further, by providing the antireflection layer 15 from the inner wall surface 9A of the through hole 9 of the substrate 6 to the upper surface 6B of the substrate 6, the reflection of the light incident on the upper surface 6B of the substrate 6 is performed as in the first embodiment. Is prevented by the anti-reflection layer 15, and the incidence of unnecessary light on the imaging unit 10 due to irregular reflection in the lens unit 8 can be effectively prevented.

In the first to third embodiments, an example of application to the image pickup apparatus 2 including the substrate 6, the image pickup device 7, and the lens unit 8 has been described. However, the present invention is not limited to this. Instead, the present invention can be widely applied to a configuration in which the imaging element 7 is mounted on the lower surface 6A of the substrate 6 in a state where the imaging unit 10 is exposed from the through hole 9 using the substrate 6 having the through hole 9 for light transmission. .

More specifically, as shown in FIGS. 11 (a) and 11 (b) and FIGS. 12 (a) and 12 (b), a flat lid having a light-transmitting property is used instead of the lens unit 8 described above. The body 16 may be used. The lid 16 may be, for example, a seal glass that protects the imaging unit 10 of the imaging element 7 from adhesion of dust and the like. Further, the optical element may be an optical element including an infrared cut filter or an optical low-pass filter, or an optical element having both functions of an infrared cut filter and an optical low-pass filter.

By the way, in FIG. 11A, the lid 1
6 shows an image pickup device 2 using an anti-reflection layer 15 provided on the inner wall surface 9A of the through hole 9 of the substrate 6 in the same manner as in the first embodiment, and FIG. 1 shows a configuration in which an antireflection layer 15 is also provided on the upper surface 6B of the substrate 6. FIG. 12A shows a configuration in which the imaging device 2 using the lid 16 is formed in a state where the inner wall surface 9A of the through hole 9 of the substrate 6 is inclined as in the second embodiment. 12 (b), in the imaging device 2 using the lid 16, the inner wall surface 9A of the through hole 9 of the substrate 6 is formed in an inclined state, as in the third embodiment. The configuration in which the antireflection layer 15 is provided on the wall surface 9A and the substrate upper surface 6B following the wall surface 9A is shown.

[0045]

As described above, according to the image pickup apparatus of the present invention and the camera system using the same, the reflection of light on the inner wall surface of the through hole is prevented (or reduced) by the antireflection layer, and the image pickup is performed. Unnecessary light can be effectively prevented from entering the section. This makes it possible to prevent the occurrence of image noise due to the incidence of unnecessary light when realizing a small and thin imaging device.

According to another imaging apparatus of the present invention and a camera system using the same, by inclining the inner wall surface of the through hole at a predetermined angle, light incident on the inner wall surface of the through hole can be captured by the imaging unit. Thus, unnecessary light can be effectively prevented from entering the imaging unit. This makes it possible to prevent the occurrence of image noise due to the incidence of unnecessary light when realizing a small and thin imaging device.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing an overall configuration of a camera system according to the present invention.

FIG. 2 is a side sectional view showing a configuration of the imaging device according to the first embodiment of the present invention.

FIG. 3 is a plan view showing an arrangement relationship between a substrate and an image sensor.

FIG. 4 is a diagram illustrating the operation and effect of the imaging device according to the first embodiment.

FIG. 5 is a cross-sectional view illustrating a main part of an application example of the imaging apparatus according to the first embodiment.

FIG. 6 is a side sectional view showing a configuration of an imaging device according to a second embodiment of the present invention.

FIG. 7 is a diagram for explaining a setting condition of an inclination angle of an inner wall surface.

FIG. 8 is a diagram illustrating an operation and effect of the imaging device according to the second embodiment.

FIG. 9 is a side sectional view illustrating a configuration of an imaging device according to a third embodiment of the present invention.

FIG. 10 is a diagram illustrating the operation and effect of the imaging device according to the third embodiment.

FIG. 11 illustrates another application example of the present invention (part 1).
It is.

FIG. 12 illustrates another application example of the present invention (part 2).
It is.

FIG. 13 is a side sectional view showing a configuration of a conventional imaging device.

FIG. 14 is a side cross-sectional view illustrating a configuration of an imaging device that can be reduced in size and thickness.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Camera system, 2 ... Imaging device, 6 ... Substrate, 7 ... Imaging element, 8 ... Lens unit, 9 ... Through hole, 9A ... Inner wall surface, 10 ... Imaging part, 15 ... Anti-reflection layer

Claims (7)

[Claims] 1. A light-transmitting through-hole is provided,
An imaging device comprising: a substrate having an anti-reflection layer provided on an inner wall surface of the through hole; and an imaging element mounted on one surface of the substrate in a state where an imaging unit is exposed from the through hole. . 2. A through hole for light transmission is provided,
A substrate formed such that an inner wall surface of the through hole is inclined at a predetermined angle; and an imaging element mounted on one surface of the substrate in a state where an imaging unit is exposed from the through hole. Imaging device. 3. The imaging device according to claim 1, wherein an antireflection layer is provided on the other surface of the substrate. 4. The imaging device according to claim 1, wherein an inner wall surface of the through hole is formed to be inclined at a predetermined angle. 5. The imaging device according to claim 3, wherein an inner wall surface of the through hole is formed to be inclined at a predetermined angle. 6. A through hole for light transmission is provided,
A substrate provided with an anti-reflection layer on an inner wall surface of the through hole, and an imaging device including an imaging element mounted on one surface of the substrate in a state where an imaging unit is exposed from the through hole. Characterized camera system. 7. A through hole for light transmission is provided,
An imaging device comprising: a substrate formed such that an inner wall surface of the through hole is inclined at a predetermined angle; and an imaging element mounted on one surface of the substrate in a state where an imaging unit is exposed from the through hole. A camera system characterized by using: