JPH04282991A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To facilitate the assembling by providing a color moire prevention means to a transparent plate of a solid-state image pickup element package opposite to a face of the solid-state image pickup element so as to eliminate the need for a color moire prevention glass. CONSTITUTION:A solid-state image pickup element package of a solid-state image pickup device in which the solid-state image pickup element package, a color moire prevention glass and an optical lens are integrated is provided with a transparent plate 5 so as to cover a recessed part of a case 2, and a color moire prevention means is provided to the transparent plate 5 opposite to a face of the solid-state image pickup element 3. Since the color moire prevention means has the entirely same function as that of the optical LPF, the color moire prevention glass is not required in the integrated assembly and the assembling is facilitated. Moreover, the color moire prevention means provided to the transparent plate 5 is preferably made of a diffraction grating subject to mold forming with a plate member laminated onto the transparent plate.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a solid-state imaging device.
The present invention relates to a solid-state imaging device used, for example, in a home VTR-integrated camera or a general surveillance camera.

0002

2. Description of the Related Art Conventionally, this type of solid-state imaging device has been constructed as shown in FIG. 7, for example.

In the figure, first, there is a substrate 21, and a solid-state image sensor package 11 is located approximately in the center of this substrate 21.
is installed. The external lead of the solid-state image sensor package 11 is drawn out to the back surface of the substrate 21 through a hole formed in the substrate 21.

[0004] An infrared cut filter 13 is arranged on the surface of the transparent plate of the solid-state image sensor package 11 via a rubber packing 14, and a crystal filter is formed on the upper surface of the infrared cut filter 13. Optical low-pass filters 12 are laminated.

These optical low-pass filters 12 and infrared cut filters 13 are installed in a solid-state image sensor package 11.
There is a sensor holder 22 for pressing on the side, and this sensor holder 22 is fixed to the substrate 21 with screws 23.

A lens mount 31 is attached to the sensor holder 22 with a screw 32, and the lens mount 31 holds an optical lens 34 positioned above the optical low-pass filter 12.

Note that the optical low-pass filter 12 serves as a color moiré prevention glass. That is, by utilizing the birefringence of crystal, a birefringent ray is made incident at a position shifted by a distance corresponding to 1/2 of the pixel pitch of the solid-state image sensor with respect to the chief ray, and the outline of the optical image projection area is This is to reduce rainbow coloring caused by color moiré. The amount of deviation between the principal ray and the birefringent ray can usually be set by adjusting the thickness of the crystal filter.

FIG. 8 is a sectional view for explaining details of the solid-state image sensor package 11. As shown in FIG.

In the figure, there is a solid-state image sensor 3, which is mounted in a housing 2 made of, for example, a resin material. The housing 2 houses the solid-state image sensor 3.
The solid-state imaging device 3 is disposed within the recess. and,
The concave portion of the housing 2 is closed by a transparent plate 5 made of a glass cap.

Further, a plurality of external lead leads 1 are protruded from the casing 2, and the tips of the external lead 1 inside the casing 2 are connected to the main body of the solid-state image pickup device 3 via bonding wires 4, respectively. It is connected to each electrode on the surface.

[0011]The package structure of the solid-state image sensor is as follows:
For example, it is known from "Video Information", "Special Feature: Recent Trends in Solid-State Image Sensors and Solid-State Cameras", page 31, May 1986; published by Japan Industrial Development Corporation.

0012

However, in the conventional solid-state imaging device configured as described above, the optical low-pass filter 12 must first be disposed between the solid-state imaging device package 11 and the optical lens 34. Therefore, the solid-state image sensor package 11, the rubber packing 14, the optical low-pass filter 12, and the optical lens 34 must be assembled by aligning them on the optical axis with high precision. Therefore, the sensor holder 22 is required. However, there were problems in that it was expensive and the assembly was complicated.

In particular, in order to accurately perform the function of the optical low-pass filter 12, the distance from the solid-state image sensor package must be set accurately.
This made the assembly described above more complicated.

Furthermore, the optical low-pass filter 12 is constructed by optically polishing a birefringent crystal, and is expensive and has a limit on its minimum thickness, making the entire device heavy. There was also the problem that it had been left behind.

Furthermore, since the above-mentioned optical low-pass filter 12 is relatively large, there is a problem in that there is a limit to the miniaturization of the entire device.

[0016] Therefore, the present invention has been made based on these circumstances, and its object is to provide a solid-state imaging device that is easy to assemble.

Another object of the present invention is to provide a solid-state imaging device that can be made smaller and lighter at lower cost.

[0018]

[Means for Solving the Problems] In order to achieve the above object, the present invention basically includes a built-in solid-state image sensor and a transparent plate disposed on the light image projection surface side of the solid-state image sensor. a solid-state image sensor package, a color moiré prevention glass placed on the transparent plate side of the solid-state image sensor package,
In the solid-state imaging device which integrates and incorporates an optical lens disposed on the light projection side of the color moiré prevention glass, the solid-state image sensor package, the color moire prevention glass, and the optical lens, the solid-state image pickup device of the transparent plate is provided. The device is characterized in that a color moire prevention means is provided on the side facing the element, thereby eliminating the need for the color moire prevention glass.

[0019] As the color moiré prevention means,
For example, it consists of a diffraction grating formed on the surface of the transparent plate.

[0020]

According to the present invention, a means for preventing color moiré is provided by forming a diffraction grating on a transparent plate, which is, for example, a glass cap of a solid-state imaging device package.

[0021] Here, the optical low-pass filter constituted by the diffraction grating can set the amount of deviation between the principal ray and the diffracted ray by the height and pitch of the diffraction grating. It can have exactly the same function as a standard low-pass filter.

[0022] The solid-state imaging device configured as described above includes a solid-state imaging device package, color moiré prevention glass,
Also, in the integrated assembly with the optical lens, the color moiré prevention glass is no longer required, so the assembly can be facilitated.

In this case, in order for the color moiré prevention glass to perform its function accurately, the separation distance from the solid-state image sensor package must be set accurately. What is needed is that the assembly can be made easier.

[0024]The color moiré prevention means built into the solid-state image sensor package is, for example, a diffraction grating formed on a transparent plate that serves as the glass cap of the solid-state image sensor package, so it is extremely heavy. It is small, so it goes without saying that the entire device can be made lighter, and it also becomes possible to achieve miniaturization and cost reduction.

[0025]

[Example] Example 1. FIG. 1 is a cross-sectional configuration diagram showing an embodiment of a solid-state image sensor package according to the present invention.

In the figure, there is a solid-state image sensor 3, which is mounted in a housing 2 made of, for example, molded resin. That is, the housing 2 has a concave portion formed approximately at the center of its main surface, and the solid-state image sensor 3 is mounted on the bottom surface of this concave portion.

The solid-state image sensing device 3 has a main surface (a surface opposite to the surface on which it is mounted) formed with a light image projection area in which, for example, photodiodes are formed in a matrix. It is something that exists.

A plurality of external lead leads 1 are provided penetrating through the side surface of the casing 2, and their bases are close to a plurality of electrodes (not shown) formed on the main surface of the solid-state image sensor 3. It is located. Further, the tip of the external lead 1 extends outside the casing 2, and is of a so-called dual in-line type.

Bonding wires 4 are connected between each electrode of the solid-state image sensor 3 and the base of each external lead 1.
are bonded to make an electrical connection.

[0030] The transparent plate 5 is disposed so as to cover the concave portion of the casing 2 in which the solid-state image sensor 3 is mounted. The housing 2 and the transparent plate 5 are fixed to each other by, for example, an adhesive (not shown).

The transparent plate 5 is made of, for example, amorphous polyolefin APO (for example, polyolefin APO manufactured by Mitsui Petrochemical Co., Ltd.). This amorphous polyolefin APO is a resin with well-balanced physical properties as a material for optical lenses, and has heat resistance, moisture resistance, transparency, etc. The resin also has excellent moldability.

Further, this transparent plate 5 has a diffraction grating formed on its surface facing the solid-state image sensor 3.

FIG. 3 shows a sectional view of the transparent plate 5 on which a diffraction grating is formed. The diffraction grating is formed by alternately forming grooves and protrusions on one surface of the transparent plate 5 in a direction perpendicular to the plane of the paper.

In this case, the amount of deviation between the principal ray and the diffracted ray can be set by the height h and pitch p of the diffraction grating,
It can have exactly the same function as a conventional optical low-pass filter that utilizes the birefringence of crystal.

This diffraction grating is formed at the same time when the transparent plate 5 itself is formed by molding. For example, if the pixel pitch of the solid-state image sensor 11 is 9.6 (horizontal) x 7.5 (vertical) and the distance to the solid-state image sensor 11 is 1.0 mm, the height is 0.8 μm and the pitch is 40 μm. By setting it to , it becomes possible to obtain the same function as a conventionally used crystal filter.

Although the grooves and projections constituting the diffraction grating shown in FIG. 3 are all trapezoidal in cross-section, they are not limited to this shape; , or a sine wave shape, etc., similar effects can be obtained.

Furthermore, the surface of the transparent plate 5 opposite to the surface on which the diffraction grating is formed is colored with a pigment or dye to constitute an infrared cut filter.

The pigment or dye is preferably of cyan color, for example, and has spectral transmittance characteristics as shown in FIG.

The transparent plate 5 on which the diffraction grating and the infrared cut filter are formed in this way is coated with a hard coating having an antireflection effect consisting of, for example, three layers, including the diffraction grating and the infrared cut filter surface. It has been treated to improve light transmittance. According to experiments, it has been found that the hard coating treatment improves the light transmittance by 5 to 8%.

According to the embodiment described above, by forming a diffraction grating on the transparent plate 5, which is the glass cap of the solid-state image sensor package 11, an optical low-pass filter, which is a means for preventing color moiré, is provided. .

Since the optical low-pass filter built into the solid-state image sensor package 11 can be placed extremely close to the solid-state image sensor 3 in this way, the separation distance from the solid-state image sensor 3 can be set accurately. , whereby the effect as an optical low-pass filter can be improved.

Note that the optical low-pass filter using a diffraction grating is not built into the solid-state image sensor package 11, and may be placed at the position of a conventional optical low-pass filter using crystal, or at the position of a lens aperture (not shown). Conceivable. However, if you do this, in the former case,
It turned out that the ghost image caused by the internal reflection of the lens became checkered and unsightly. Furthermore, in the latter case, it has been found that when the pupil diameter of the lens changes, the low-pass effect also changes.

Example 2. FIG. 2 is a cross-sectional configuration diagram showing an embodiment of a solid-state imaging device according to the present invention.

In the figure, first, there is a substrate 21 made of aluminum, for example, and the solid-state image sensor 11 is mounted approximately in the center of this substrate 21. The external lead of the solid-state image sensor 11 is led out to the back surface of the substrate 21 through a hole formed in the substrate 21.

Here, the solid-state image sensor package 11
has the same configuration as the solid-state image sensor package 11 shown in FIG. That is, the solid-state image sensing device package 11 already has a built-in color moiré prevention means and an infrared cut filter.

A lens mount 3 is attached to the main surface of the solid-state image sensor package 11 via a rubber packing 14.
1 is attached, and this lens mount 31 is attached with a screw 23.
It is fixed to the substrate 21 by. Further, this lens mount 31 is adapted to hold an optical lens 34 positioned on the solid-state image sensor package.

The solid-state imaging device configured as described above has, on the main surface side of the solid-state imaging device package 11, not only the color moire prevention means and the infrared cut filter, but also the color moire prevention means and the infrared cut filter. There is no need to provide the sensor holder 22 for accurately positioning the sensor with respect to the solid-state image sensor package 11. That is, it is sufficient that the optical lens 34 and the lens mount 31 that holds the optical lens 34 are provided.

[0048] Therefore, it is possible to achieve reductions in size, cost, and weight compared to the prior art.

Furthermore, assembly of the lens mount 31 and the like can be facilitated since there is no need to incorporate color moiré prevention means or the like.

Example 3. FIG. 5 is a cross-sectional configuration diagram showing another embodiment of the solid-state image sensor package according to the present invention.

In the figure, the same reference numerals as in FIG. 1 indicate the same materials. The configuration that differs from FIG. 1 is in the optical low-pass filter 6. The optical low-pass filter 6 is composed of an independent plate-shaped diffraction grating, and is spaced apart from the transparent plate 5 and placed close to the solid-state image sensor 3. A stepped portion is formed on the inner surface of the recessed portion of the housing 2, and the optical low-pass filter 6 is supported and fixed at this stepped portion via, for example, an epoxy adhesive. .

In this case, the optical low-pass filter 6 is made of the above-mentioned materials, but the transparent plate 5 is made of a different material from the optical low-pass filter 6. You can do it as you like.

However, in this case, if the housing 2 is made of resin, both the optical low-pass filter 6 and the transparent plate 5 are made of resin, so that the linear expansion coefficients of both are close to each other. This has the effect of increasing the reliability of both adhesive surfaces against temperature changes.

In the embodiment described above, the transparent plate 5 on which the diffraction grating is formed is made of resin mold. However, it goes without saying that the structure is not limited to this, and may be formed by processing a glass substrate.

An example of a method for manufacturing a glass substrate on which a diffraction grating is formed will now be described with reference to FIG.

Step 1. As shown in (a), a glass substrate 61 having a spectral transmittance suitable as an infrared cut filter is prepared, and its diffraction grating forming surface (lower surface in the figure) is cleaned.

Step 2. As shown in (b), a film-like body 62 is formed on the diffraction grating formation surface. This film-like body 62 is formed, for example, as follows. A predetermined amount of dopant is added to the photosensitive copolymer to prepare a toluene solution, which is filtered through a membrane filter. This solution is spin-coated onto the glass substrate to form a film, followed by heat treatment.

Step 3. As shown in (c), ultraviolet rays are irradiated through a photomask 63. At this time, the film-like body 62 and the photomask 63
A predetermined interval is set in between, and the light profile is continuously changed from the exposed part to the light-blocking part with a predetermined light profile. Here, the photomask 63 has exposed portions and light shielded portions in a periodic pattern.

Step 4. As shown in (d), the unreacted dopant is sublimated by heating under reduced pressure, and the pattern of the photomask is formed on the film-like body 62.
Form on top. Since the photosensitive copolymer and dopant react in the exposed areas of the photomask, the film thickness and refractive index of the photosensitive resin increase. In addition, the photosensitive copolymer and the dopant do not react in the light-shielding part, and the dopant sublimes by heating under reduced pressure, so there is no increase in the film thickness and refractive index. As a result, an optical low-pass filter consisting of a diffraction grating whose film thickness and refractive index periodically change is formed.

In each of the embodiments described above, an infrared cut filter as well as an optical low-pass filter is built into the solid-state image sensor package. However, the present invention is not limited to this, and only an optical low-pass filter may be incorporated. In this case, even if the infrared cut filter is placed outside the solid-state image pickup device package, its accuracy is not required, so the assembly will not be so complicated.

[0061]

[Effect of the invention] As is clear from the above explanation,
According to the solid-state imaging device according to the present invention, assembly can be made extremely easy.

[0062] Further, it becomes possible to achieve further reduction in size and weight.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram showing an embodiment of a solid-state image sensor package according to the present invention.

FIG. 2 is a cross-sectional configuration diagram showing an embodiment of a solid-state imaging device according to the present invention.

FIG. 3 is a cross-sectional configuration diagram showing one embodiment of an optical low-pass filter used in the present invention.

FIG. 4 is a graph showing an example of the characteristics of an infrared cut filter used in an example of the present invention.

FIG. 5 is a cross-sectional configuration diagram showing another embodiment of the solid-state image sensor package according to the present invention.

FIGS. 6(a) to 6(d) are cross-sectional process diagrams showing one embodiment of a method for manufacturing an optical low-pass filter used in the present invention.

FIG. 7 is a cross-sectional configuration diagram showing an example of a conventional solid-state imaging device.

FIG. 8 is a cross-sectional configuration diagram showing an example of a conventional solid-state image sensor package.

[Explanation of symbols]

2 Housing 3 Solid-state image sensor 5 Transparent plate 6. Optical low-pass filter 11 Solid-state image sensor package 31 Lens mount 34 Optical lens

Claims (4)

[Claims] 1. A solid-state image sensor package that includes a built-in solid-state image sensor and a transparent plate disposed on the light image projection surface side of the solid-state image sensor, and a color moiré package disposed on the transparent plate side of the solid-state image sensor package. In the solid-state imaging device comprising a color moiré prevention glass, an optical lens disposed on the light projection side of the color moiré prevention glass, the solid-state image sensor package, the color moiré prevention glass, and the optical lens integrally incorporated, the transparent plate A solid-state imaging device, characterized in that color moiré prevention means is provided on the side facing the solid-state imaging element, thereby eliminating the need for the color moiré prevention glass. 2. The solid-state imaging device according to claim 1, wherein the color moiré prevention means is a diffraction grating molded from a plate material laminated on the transparent plate. 3. The solid-state imaging device according to claim 1, wherein the color moiré prevention means comprises a plate-shaped diffraction grating that is spaced apart from the transparent plate and close to the solid-state imaging device. A solid-state imaging device. 4. The solid-state imaging device according to claim 1, wherein the color moiré prevention means formed on the surface of the transparent plate facing the solid-state imaging device includes a molded diffraction grating on the surface of the transparent plate facing the solid-state imaging device. A solid-state imaging device characterized in that it is formed and configured.