JPH0823085A - Solid state image pickup device - Google Patents

Abstract

PURPOSE:To prevent a light-permeable window sealed in a package with adhesives from dewing on its inner surface if moisture enters a chip mounting space by forming a transparent and hygroscopic resin film on this surface. CONSTITUTION:A resin-made hollow package 2 houses a CCD image chip 3 sealed with a glass window 4. A transparent and hygroscopic resin film 6 is formed on the inner surface of the window 4 and preferably made of a hygroscopic metacrylate polymer or copolymer thereof. When the title device is left long in a high-humidity atmosphere enough to penetrate the moisture into a space round the chip and rapidly cooled to rise the relative humidity in the space with reduction of the temp., the resin film on the inner surface of the window quickly absorbs the moisture to thereby lower the relative humidity and prevent the window inner surface and chip surface from dewing.

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 using a CCD image chip.

[0002]

2. Description of the Related Art Conventionally, in this type of solid-state image pickup device, a CCD image chip is installed in a ceramic hollow package and is sealed by a window material made of glass.

[0003]

Since the conventional ceramic package is expensive, a cheaper resin package is desired. However, in a solid-state imaging device including a resin package, when left in a high humidity environment for a long time, moisture penetrates through the resin package into the chip installation space and reaches a humidity close to the ambient humidity. When the apparatus is moved to a low temperature environment in such a moisture absorption state, there is a problem that relative humidity inside the space becomes saturated and dew condensation occurs on the inner surface of the window, causing a problem.

An object of the present invention is to provide a solid-state image pickup device which is inexpensive and which does not cause dew condensation on the inner surface of the window even when moisture enters the chip installation space.

[0005]

A solid-state image pickup device according to the present invention comprises a hollow resin package accommodating a CCD image chip, and a light-transmissive window portion adhesively sealed in the package.
A transparent resin film having a hygroscopic property applied to the inner surface of the window portion is provided.

The transparent and hygroscopic resin film is a hygroscopic acrylic polymer or hygroscopic methacrylic polymer, or a hygroscopic resin or maltotriose having a hydrophobic monomer as a main component and copolymerized with them. Composed of compounds.

The light transmitting window portion is made of glass, an organic polymer, or a composite system thereof.

[0008]

According to the structure of the present invention, since the package is made of resin, it is inexpensive. In addition, the package is adhesively sealed with a light-transmissive window material, and a transparent and hygroscopic resin film is applied and formed on the inner surface of the window, so the resin film absorbs moisture, and the inner surface of the window and the chip surface Condensation can be prevented.

[0009]

Embodiment A solid-state image pickup device according to Embodiment 1 of the present invention will be described.

FIG. 1 is a sectional view of the first embodiment. In the figure, 2 is a hollow package made of resin, 3 is a CCD
Image chip 4, a window portion made of glass for sealing the package 2, 5 leads, and 6 a transparent and hygroscopic resin film applied to the inner surface of the window portion 4. The hollow volume of this package is about 0.04 cm ³ .

The package 2 is made of transfer mold sealing resin for semiconductor packages.

Further, the hygroscopic resin film 6 has a molar ratio of 2-hydroxyethyl methacrylate, tetrahydrofurfuryl acrylate, and glycidyl methacrylate of 1 each.
It consists of a copolymer synthesized at 7: 5: 3 and is applied to a thickness of 5 μm. Table 1 shows the saturated moisture absorption of this material at 20 ° C.

Next, a solid-state image pickup device according to a second embodiment of the present invention will be described. This Example 2 has the same structure as the example shown in FIG. 1, and the hygroscopic resin film 6 is made of a polymer of maltotriose (Pullulan: manufactured by Hayashibara Co., Ltd.) and is applied to a thickness of 1 μm. There is. The moisture absorption of this material is shown in Table 1.

The window 4 is made of norbornene resin ZEONEX (product of Nippon Zeon Co., Ltd.).

[0015]

[Table 1]

As a comparative example, a solid-state image pickup device having the same structure as the solid-state image pickup device of the above-mentioned embodiment but not provided with a hygroscopic resin film was used.

The solid-state image pickup devices of the above-mentioned examples and comparative examples were left in an environment of temperature 85 ° C. and relative humidity of 85% for 100 hours, and then rapidly moved to each environment of temperature 0 ° C., 10 ° C., 20 ° C. The conditions of condensation on the inner surface of the window 4 were observed and compared.

In the comparative example, dew condensation occurred in the environment of all temperatures, but in the apparatus of the example, no dew condensation was observed in the environment of all temperatures,
In addition, no operational problems occurred.

The solid-state imaging devices of the above-mentioned examples and comparative examples were left in an environment of a temperature of 40 ° C. and a relative humidity of 90% for 1000 hours, and then rapidly moved to an environment of 0 ° C. and 23 ° C. The situation of dew condensation on the inner surface of Part 4 was observed and compared.

In the comparative example, dew condensation occurred in both environments,
No condensation was observed in the devices of the examples in both environments.
In addition, no operational problems occurred.

The hollow resin package 2 is not limited to the semiconductor encapsulation resin, and molding materials such as thermosetting and thermoplastic resins can be widely applied.

Further, the hygroscopic resin film 6 is not limited to the material of the embodiment, and has an excellent light transmittance, a moisture absorption amount of not less than 2.0% by weight at a relative humidity of 50%, and a relative humidity of 9%.
A material having a moisture absorption amount at 5% of 2.5 times or more the moisture absorption amount at a relative humidity of 50%, and capable of quickly absorbing and dehumidifying in response to changes in the relative humidity of the environment can be preferably applied.

The thickness of the resin film is appropriately determined based on the volume of the package hollow portion and the hygroscopic property of the resin.

Further, the window portion 4 is not limited to the material of the embodiment, but can be widely applied to a transparent plastic material such as acrylic resin or polycarbonate, or a material in which glass is compounded on the surface of the transparent plastic material.

Further, since the light-transmissive window portion is adhered and sealed to the package and the transparent and hygroscopic resin film is applied to the inner surface of the window portion, the device is left in a high humidity atmosphere for a long time, When moisture enters the surrounding space and is rapidly cooled, and the relative humidity in the space rises as the temperature decreases, the hygroscopic resin film on the inner surface of the window quickly adsorbs the moisture, and the relative humidity increases. To prevent condensation on the inner surface of the window and the surface of the chip. Therefore, it has the same high reliability as the solid-state imaging device of the ceramic package.

[0026]

According to the solid-state image pickup device of the present invention, since the package is made of resin, it is inexpensive.

[Brief description of drawings]

FIG. 1 is a sectional view of a solid-state imaging device according to the present invention.

[Explanation of symbols]

 1 Solid-state imaging device 2 Hollow resin package 3 CCD image chip 4 Light transmissive window 6 Hygroscopic resin film

Claims (4)

[Claims] 1. A hollow resin package accommodating a CCD image chip, a light-transmissive window part sealed in the package, and a transparent and hygroscopic resin formed on the inner surface of the light-transmissive window part. A solid-state imaging device including a film. 2. The solid-state imaging device according to claim 1, wherein the resin film is made of a hygroscopic acrylate, a hygroscopic methacrylate polymer, or a copolymer containing them as a main component. 3. The solid-state imaging device according to claim 1, wherein the resin film is made of a maltotriose compound. 4. The solid-state imaging device according to claim 1, wherein the light transmissive window is made of glass or an organic polymer.