Cooled CCD camera

Details Cooled CCD camera Cooled CCD camera

1998-01-14

2001-10-23

Ho, Tuan (Department: 2612)

Television

Camera, system and detail

Optics

C348S374000, C359S507000

Reexamination Certificate

active

06307590

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a cooled CCD (Charge Coupled Device) camera and, particularly, to such a cooled CCD camera of simple structure that is easy to mount and has improved cooling efficiency.
DESCRIPTION OF THE PRIOR ART
A chemiluminescent detecting system is known, which comprises the steps of selectively labeling a fixed high molecular substance such as a protein or a nucleic acid sequence with a labeling substance which generates chemiluminescent emission when it contacts a chemiluminescent substance, contacting the high molecular substance selectively labeled with the labeling substance and the chemiluminescent substance, photoelectrically detecting the chemiluminescent emission in the wavelength of visible light generated by the contact of the chemiluminescent substance and the labeling substance and producing digital image signals, effecting image processing thereon, and reproducing a chemiluminescent image on a display means such as a CRT or a recording material such as a photographic film, thereby obtaining information relating to the high molecular substance such as genetic information.
Further, a fluorescence system using a fluorescent substance as a labeling substance is known. According to this system, it is possible to study a genetic sequence, the expression level of a gene and the metabolism, absorption, excretion path and state of a substance introduced into a test mouse and to effect separation or identification of protein or estimation of the molecular weight or properties of protein or the like. For example, this system can perform a process including the steps of distributing a plurality of DNA fragments on a gel support by means of electrophoresis after a fluorescent dye was added to a solution containing a plurality of DNA fragments to be distributed or distributing a plurality of DNA fragments on a gel support containing fluorescent dye or dipping a gel support on which a plurality of DNA fragments have been distributed by means of electrophoresis in a solution containing fluorescent dye, thereby labeling the electrophoresis-distributed DNA fragments, exciting the fluorescent dye by a stimulating ray to cause it to release a fluorescent light, detecting the released fluorescent light to produce an image and detecting the distribution of the DNA on the gel support. This system can also perform a process including the steps of distributing a plurality of DNA fragments on a gel support by means of electrophoresis, denaturing the DNA, transferring at least a part of the denatured DNA fragments onto a transfer support such as a nitrocellulose support by the Southern-blotting method, hybridizing a probe prepared by labeling target DNA and DNA or RNA
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complementary thereto with the denatured DNA fragments, thereby selectively labeling only the DNA fragments complementary to the probe DNA or probe RNA, exciting the fluorescent dye by a stimulating ray to cause it to release a fluorescent light, detecting the released fluorescent light to produce an image and detecting the distribution of the target DNA on the transfer support. This system can further perform a process including the steps of preparing a DNA probe complementary to DNA containing a target gene labeled by a labeling substance, hybridizing it with DNA on a transfer support, combining an enzyme with the complementary DNA labeled by a labeling substance, causing the enzyme to contact a fluorescent substrate, transforming the fluorescent substrate to a fluorescent substance having a fluorescent light releasing property, exciting the thus produced fluorescent substance by a stimulating ray to release fluorescent light, detecting the fluorescent light to produce an image and detecting the distribution of the target DNA on the transfer support. This fluorescence detecting system is advantageous in that a genetic sequence or the like can be easily detected without using a radioactive substance.
In the case where such chemiluminescent emission or fluorescent light is detected by a cooled CCD camera to produce a chemiluminescent image or a fluorescent image, since chemiluminescent emission or fluorescent light is very weak, the cooled CCD camera has to be exposed thereto for a long time. However, it is known that when the cooled CCD camera is exposed for a long time, noise is generated in the image by heat emitted from the CCD. Therefore, for reducing noise in the image caused by heat generated by the CCD, the cooled CCD camera for detecting very weak light such as chemiluminescent emission or fluorescent light is constituted by providing the CCD, a heat transfer plate made of a metal, a cooling element for cooling the CCD and a substrate on which electronic parts are mounted within an airtight package.
A conventional airtight metal package is made of stainless steel, Kovar or the like from the viewpoint of workability. Therefore, the heat transfer coefficient is low and the efficiency of heat dispersion and heat transfer is insufficient and drop-like condensation occurs on the light incident window, which is made of optical glass or the like and mounted on the package. Accordingly, a heater is provided in a conventional cooled CCD camera for preventing the drop-like condensation.
However, not only complicates the structure and increases a cost but also degrades the cooling efficiency, provision of an additional means such as a heater.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a cooled CCD camera of simple structure that is easy to mount and has improved cooling efficiency.
The above and other objects of the present invention can be accomplished by a cooled CCD camera comprising a CCD, a heat transfer plate, a cooling element for cooling the CCD, a substrate on which electronic parts are mounted and an airtight package for accommodating them, the package being made of aluminum alloy, an optical glass plate being airtightly mounted on the package by sealing with glass having a melting point from 400 to 450° C. and connector terminals for connecting the CCD to the outside being airtightly mounted on the package by sealing with glass having a melting point from 400 to 450° C.
The aluminum alloy has a much higher heat transfer coefficient than that of stainless steel, Kovar or the like but is hard to process by welding. In particular, a high temperature is required when a connector terminal to the outside is airtightly mounted by welding, thereby increasing the risk of damage to the CCD and the electronic parts. On the other hand, it is extremely difficult to airtightly mount the connector terminal by means of vacuum brazing. Therefore, aluminum alloy has seldom been employed as the material for the airtight package of a cooled CCD camera.
However, according to the present invention, the optical glass plate forming a light incident window and the connector terminals for connecting to the outside are airtightly mounted on the package by sealing with glass having a low melting point from 400 to 450° C. Therefore, since the airtight package of the cooled CCD camera can be formed by aluminum alloy having a much higher heat transfer coefficient than that of the material of the conventional airtight package such as stainless steel and Kovar, the cooling efficiency can be markedly improved, thereby preventing drop-like condensation on the optical glass plate without any additional means such as a heater and, therefore, the structure of the cooled CCD camera can be simplified. Further, since the optical glass plate and the connector terminals connecting the CCD to the outside can be airtightly mounted on the package without need for high-temperature welding or vacuum brazing, the cooled CCD camera can be easily assembled.
The above and other objects and features of the present invention will become apparent from the following description made with reference to the accompanying drawings.


REFERENCES:
patent: 4594613 (1986-06-01), Shinbori et al.
patent: 5508740 (1996-04-01), Miyaguchi et al.
patent: 5534725 (1996-07-01), Hur
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