JPH06252371A - Solid image pickup device - Google Patents

Abstract

PURPOSE:To accurately control the interval between the surface of a solid image pickup element and the surface of the diffraction grating of an optical low-pass filter and the inclination by forming a projection at the diffraction grating optical low-pass filter opposed to the solid image pickup element, and forming a fixing part between the projection and the surface of the solid image pickup element. CONSTITUTION:A solid image pickup element 21 is fixed to the bottom 27 of an envelope by a binder 30, and a diffraction grating type optical low-pass filter 22 is arranged in piles on this. Projections 31 are installed at, for example, the four corners of the diffraction grating type optical low-pass filter 22. And, for example, an adhesive layer 32 is applied between the projection 31 of the diffraction grating type optical low-pass filter 22 and the solid image pickup element 21 so as to fix both. Hereby, it becomes possible to maintain the distance between the diffraction grating type of optical low-pass filter and the solid image pickup element at a specified value, and also, suppress the inclination of the diffraction grating type optical low-pass filter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device, and is particularly suitable for a type having an optical low-pass filter.

[0002]

2. Description of the Related Art Conventionally, a solid-state image pickup device obtains color signals by arranging color filters in a vertical and horizontal mosaic pattern. However, a subject to be photographed contains a frequency component corresponding to the pitch of the color filters. Then, this is detected as a color signal, and a false color signal is generated. Further, in the solid-state imaging device, pixels are arranged discontinuously and regularly, and when a subject contains a high frequency component equal to or larger than a pixel pitch, a false signal is generated due to aliasing.

A movie camera or the like using a solid-state image pickup device requires an optical low-pass filter for limiting high frequency components of a subject in order to reduce such false color signals and false signals. As a low-pass filter, a type in which a birefringent plate such as a crystal is installed between a solid-state image pickup device and an image pickup lens has been widely used.

However, since a birefringent plate such as a crystal is poor in mass productivity and expensive, an optical low-pass filter using a diffraction grating which is inexpensive and rich in mass productivity has recently been proposed. . Further, a type has been developed in which an optical low-pass filter is installed inside the solid-state image pickup device, that is, between the protective glass and the solid-state image pickup device in order to cope with miniaturization, a variable lens diaphragm, and a zoom lens. In this type, a method of laminating a diffraction grating type low-pass filter on a solid-state image sensor is used.

A conventional solid-state image pickup device will be described with reference to the sectional views of FIGS. In the envelope 2 having the hollow portion 1, the protective glass 3 covering the opening surface a is fixed by the adhesive layer 4 for the seal, but in the hollow portion 1, the solid-state image sensor 5 and the diffraction grating type optical are naturally provided. A static low-pass filter-6 is installed.

A wall portion 7 which constitutes the hollow portion 1 is formed in the envelope 2, and a sealing adhesive layer 4 is applied to the uppermost layer portion of the wall portion 7 to fix the protective glass 3 to the wall portion 7. The step portion 8 is continuously installed, and the bottom portion 9 is integrally formed with the step portion 8 to form the envelope 2. The solid-state image pickup device 5 is fixed to the bottom portion 9 via, for example, a die bond adhesive layer 10, and a diffraction grating type optical roller is fixed to the solid state image pickup device 5.
The pass filter-6 is arranged so as to overlap. The fixing means is
For example, a method of installing the adhesive material 11 on both ends is adopted.

The distance d (see FIG. 1) between the diffraction grating type optical low-pass filter 6 and the solid-state image pickup device 5 should be maintained so as to maintain a predetermined value. reference)
Also consider.

As is apparent from FIG. 1, the diffraction grating type optical low-pass filter 6 has a sine wave-shaped surface facing the solid-state image pickup element 5, and the pitch of one of the surfaces is a solid-state image pickup element. It is usual that the pitch is equal to the pitch of the vertical and horizontal patterns formed in No. 5, or is an integral multiple or integral multiple.

[0009]

Thus, in the solid-state image pickup device of the type in which the diffraction grating type low-pass filter is installed,
Usually, both are fixed with a paste-like epoxy resin or polyimide resin, but it is difficult to control the distance d between the diffraction grating surface and the solid-state image sensor surface and the inclination θ with high accuracy. Further, in the diffraction grating type optical low-pass filter, the distance d between the surface of the diffraction grating and the surface of the solid-state image sensor and the inclination θ.
Requires high precision in order to maintain the characteristics of the diffraction grating type optical low-pass filter. Although it depends on the design of the diffraction grating, for example, an accuracy of ± 4 μm in the space dimension d and an accuracy of ± 0.01 ° in the inclination θ are required.

The present invention has been made under such circumstances, and an object thereof is to control the distance and inclination between the surface of the solid-state image pickup device and the diffraction grating surface of the optical low-pass filter with high accuracy. .

[0011]

[MEANS FOR SOLVING THE PROBLEMS] An envelope having a hollow portion, an opening surface of the hollow portion, a wall portion which is continuous with the opening surface and forms a hollow portion in the envelope, and the hollow portion. Translucent protective plate that covers the opening surface of the wall portion and is attached to the wall portion, the bottom portion of the hollow portion that is continuously formed on the wall portion and is installed corresponding to the opening surface, and the solid that is fixed to the bottom portion. Image pickup element, diffraction grating type optical low-pass filter arranged so as to overlap with the solid-state image pickup element, and protrusion formed on the diffraction grating type optical low-pass filter facing the solid-state image pickup element. The solid-state image pickup device according to the present invention is characterized by the portion and the fixing portion formed between the protrusion and the surface of the solid-state image pickup element. Also, the diffraction grating type optical low-pass filter
The fixed portion formed between the surfaces of the solid-state imaging device facing the portion, the step portion that is continuous with the wall portion and constitutes the hollow portion, and the step that is arranged so as to face the step portion. The diffraction grating type optical low-pass filter is also characterized by an end and a fixed layer arranged between the two ends.

[0012]

In the solid-state image pickup device according to the present invention, a method is adopted in which the protrusion is formed in the low-pass filter portion facing the solid-state image pickup element. The height of this protrusion is the distance itself between the diffraction grating surface of the diffraction grating type optical low-pass filter and the solid-state image sensor, and this protrusion is the diffraction grating type optical low-pass filter. Are formed at four corners, for example. By contacting and fixing this to the solid-state image sensor, the interval and the inclination can be maintained with high accuracy.

[0013]

Embodiments of the present invention will be described with reference to FIGS. That is, as is apparent from FIGS. 3 and 8, the solid-state imaging device according to the present invention has the envelope 20.
A hollow portion 23 is provided for arranging the solid-state image pickup device 21 and the diffraction grating type optical low-pass filter 22 therein. For example, the hollow portion 23 is formed in the envelope 20 made of ceramic.
In order to form the above, in addition to providing the wall portion 25 and the step portion 26 that are continuous with the opening surface 24 of the hollow portion 23, a bottom portion 27 that is continuous with the step portion 26 is formed at a position facing the opening surface 14.

The wall 25 covers the opening surface 24 and is made of a protective glass or a protective plastic 28, that is, a translucent protective plate 28.
Are fixed by using, for example, a sealing adhesive 29. This step is final, and the following steps are performed before that.

At the bottom 27 of the envelope 20, the solid-state image sensor 2 is provided.
1 is adhered by, for example, an adhesive 30 for die bond, to which a diffraction grating type optical low-pass filter-22
The above is arranged so that the distance d therebetween and the inclination θ of the diffraction grating type optical low-pass filter 22 are controlled to predetermined values, which is a feature of the present invention.

The solid-state image pickup device 21 is fixed via the adhesive 30.
To adhere to the bottom portion 27 of the envelope 20, a load of 150 gr to 300 gr is applied to be integrated. That is, the adhesive 30
Even if the resin is an ultraviolet curable resin or a thermosetting resin, a large load is applied when the viscosity is high. The application of such a load is aimed at making the parallelism between the bottom portion 27 of the envelope 20 and the solid-state imaging device 21 accurate.

As the solid-state image pickup device 21, a so-called CC is used.
D etc. are used, and the chip size is 5 mm to 12 m
It is about m square.

For this purpose, protrusions 31 are provided at the four corners of the diffraction grating type optical low-pass filter 22 as shown in FIG. The protrusions 31 are made of glass or plastic and can be installed at three corners as shown in FIG. 5, two sides as shown in FIG. 6, or four sides as shown in FIG. 7 instead of the four corners. Then, for example, an adhesive layer 32 is applied between the protrusion 31 of the diffraction grating type optical low-pass filter 22 and the solid-state image sensor 21 to fix them.

As is clear from FIG. 3 and the like, the diffraction grating type optical low-pass filter 22 has a surface facing the solid-state image pickup device 5 formed in a sine wave shape, and the pitch of one of them is The pitch is usually equal to or an integral multiple of the pitch of the vertical and horizontal patterns formed on the solid-state image sensor 5. Further, as shown in FIGS. 4 and 8, the protrusions 31 are provided at the four corners so as to be in contact with the surface of the solid-state image sensor 21, and the adhesive layer is also used for fixing them, but the application position is as shown in FIG. , FIG. 8 and FIG.
As shown in (1), it is set at an almost intermediate position of the plate-like diffraction grating type optical low-pass filter-22. FIG. 9 shows the adhesive layer 32.
Shows the application position of the circle, the circle corresponds to it, the other is the protrusion 3
It is 1.

Furthermore, as can be seen in FIG.
3 is extended from the case of FIG. 3 and FIG. 8 to the position corresponding to the above, and the adhesive layer 32 is applied between the end and the step 26 to apply both. Stick to it.

Also for this adhesion, an ultraviolet curable resin or a thermosetting resin is applied, a load of 150 gr to 300 gr is applied, and when the viscosity is large, a large load is applied.

[0022]

In the solid-state image pickup device according to the present invention, the distance between the diffraction grating type optical low-pass filter and the solid-state image pickup device is maintained at a predetermined value, and the diffraction grating type optical low-pass filter is used. It became possible to suppress the inclination of-. That is, after the solid-state image sensor is fixed to the envelope by using an adhesive so that the parallelism between the two is a good value, the solid-state image sensor is formed by the protrusion formed on the diffraction grating type optical low-pass filter. The parallelism is maintained at a good value and both are fixed by an adhesive.

As compared with the conventional method using an adhesive directly interposed between the two, the inclination and the interval can be made more precise, and the diffraction grating type optical low-pass filter-
The characteristics of can be fully exhibited. That is, a solid-state lattice type optical
The light ray that has passed through the pass filter can be accurately incident on the solid-state image sensor.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a conventional solid-state imaging device.

FIG. 2 is a sectional view of a main part of FIG.

FIG. 3 is a sectional view showing an embodiment of the present invention.

FIG. 4 is an enlarged perspective view of a part of FIG.

5 is a diagram showing an installation position of a protrusion shown in FIG.

6 is a diagram showing another installation position of the protrusion shown in FIG.

FIG. 7 is a view showing still another installation position of the protrusion shown in FIG.

FIG. 8 is a sectional view showing another embodiment of the present invention.

9 is a diagram showing the fixed positions of the solid-state imaging device and the diffraction grating type optical low-pass filter of FIG.

FIG. 10 is a sectional view showing still another embodiment of the present invention.

[Explanation of symbols]

 1, 23: hollow part, 2, 20: envelope, 3, 28: translucent protective plate, 4, 10, 11, 29, 30, 32: adhesive, 5, 21: solid-state image sensor, 6, 22: Diffraction grating type optical low-pass filter, 7, 25: Side wall, 8, 26: Step portion, 9, 27: Bottom portion, 31: Projection portion.

Claims (3)

[Claims] 1. An envelope having a hollow portion, an opening surface of the hollow portion, a wall portion which is continuous with the opening surface and forms a hollow portion in the envelope, and an opening surface of the hollow portion. A translucent protective plate that covers and is attached to the wall portion, a bottom portion of the hollow portion that is continuously formed on the wall portion and is installed corresponding to the opening surface, and a solid-state image sensor fixed to the bottom portion, A diffraction grating type optical low-pass filter placed over the solid-state image sensor, and a protrusion formed on the diffraction grating type optical low-pass filter portion facing the solid-state image sensor, A solid-state imaging device comprising a protrusion and a fixing portion formed between the surfaces of the solid-state imaging device. 2. The solid-state image pickup device according to claim 1, further comprising a fixing portion formed between the surfaces of the solid-state image pickup element facing the diffraction grating type optical low-pass filter portion. 3. A step portion which is continuous with the wall portion and constitutes the hollow portion together, an end of the diffraction grating type optical low-pass filter which is disposed so as to face the step portion, and which is disposed between both. The solid-state imaging device according to claim 1, further comprising: