JP2013105034A - Ccd camera operated under very low temperature environment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a CCD camera capable of observing the state of an object under a very low temperature environment through various narrow routes as occasion demands.SOLUTION: The CCD camera is operated under the very low temperature environment by mounting a heater and a temperature sensor on the CCD camera operated in only the vicinity of a room temperature to keep the temperature of the CCD camera in an operation temperature range even if a temperature around the CCD camera changes. Since electric wiring is used without requiring vacuum heat insulation, the state of the object under the very low temperature environment can be observed through various narrow routes as occasion demands.

Description

  The present invention relates to a CCD camera capable of observing the state of an object placed at an extremely low temperature of 20K or less. More specifically, by installing a heater and a thermometer close to the CCD camera, the temperature of the CCD camera can be set to 0 to 40, which is the operating temperature range of the camera, even if the temperature of the observation object is an extremely low temperature of 20K or less. The present invention relates to a CCD camera that operates in a cryogenic environment characterized by being held in the vicinity of ° C.

  An object placed at a very low temperature, such as a superconducting magnet cooled with liquid helium, is confined in a heat-insulated container to provide sufficient insulation from the outside, and a space that leads from the room temperature space to the object placed at a cryogenic temperature The route must be limited, the space is narrow, and the route is often long. However, observing the state of an object placed at a cryogenic temperature from various paths as needed improves the efficiency of maintenance, research, development, etc. through grasping the state of the object placed at a cryogenic temperature and confirming safety. A big contribution.

  Conventionally, as a method of confirming the state of an object placed at an extremely low temperature, a method of opening an observation window in a vacuum insulated container and placing a photographing device therein (Patent Document 1, Patent Document 2, Patent Document 3) ) And a method of installing an optical fiber in the vicinity of an object to be observed (Patent Document 4 and Patent Document 5).

  However, in the method (Patent Document 1, Patent Document 2, and Patent Document 3) in which the imaging device is put in a vacuum insulated container, the container becomes large in order to maintain sufficient heat insulation performance, and a narrow path such as the inside of a superconducting magnet Cannot be observed through. In addition, in the method of installing an optical fiber (Patent Document 4 and Patent Document 5), since the length and curvature of the optical fiber are limited, it is not possible to arbitrarily select the distance and route to the observation target. Furthermore, the optical fiber loses its flexibility at extremely low temperatures, and the optical fiber breaks when moved. Therefore, it is necessary to fix the route to the observation target in advance, and there is a restriction that the observation target cannot be changed at any time according to the observation result.

JP-A-63-133047 Japanese Unexamined Patent Publication No. 3-223600 JP 5-327036 A Japanese Laid-Open Patent Publication No. 10-212435 JP 2011-128247 A

  An object of the present invention is to provide a CCD camera capable of observing the state of an object placed at a very low temperature from various narrow paths at any time.

  In the present invention, in order to operate a CCD camera having an operating temperature range of 0 to 40 ° C. in a cryogenic atmosphere, a heater for holding a temperature, a thermometer, and a heat insulating material are attached to the CCD camera. Operates in a cryogenic environment with a structure that allows observation of the state of an object placed at a cryogenic temperature through a narrow path by minimizing the increase in the outer diameter of the CCD camera due to the thermal insulation material for keeping the temperature of the CCD camera A CCD camera is provided. In the CCD camera of the present invention, since the wiring between the CCD element and the display device is an electric wire, it is flexible even when moved in a cryogenic atmosphere, so there is no risk of being broken like an optical fiber. It is possible to observe from various routes.

  A first aspect of the present invention is a CCD camera for observing the state of an object placed at an extremely low temperature, in which a temperature sensor and a heater are installed in close contact with the optical signal conversion unit of the CCD camera, and the outside of the heater By attaching a heat insulating material to the CCD camera, the temperature of the CCD camera is detected by the temperature sensor, and power is applied to and controlled by the heater so as to keep the temperature of the CCD camera in the operating temperature range. Provided is a CCD camera that operates in a cryogenic environment characterized by having a function of maintaining the operating temperature range of the CCD camera even when the temperature is extremely low.

  A second aspect of the invention is a CCD camera operating in a cryogenic environment according to the first aspect of the invention, wherein a high thermal conductivity metal / alloy foil or thin plate is disposed between the CCD camera and the heater. Provided is a CCD camera that operates in a cryogenic environment.

  According to a third aspect of the present invention, there is provided a CCD camera operating in a cryogenic environment according to the invention 1 or 2, wherein the heater is a constantan wire or a manganin wire. To do.

A fourth aspect of the invention is a CCD camera that operates in a cryogenic environment according to any one of the first to third aspects of the invention, wherein the heat insulating material is made of fluororesin tape so that the visual field of the CCD camera is not lost. A CCD camera that operates in a cryogenic environment is provided.

  The set temperature when controlling the temperature of the CCD camera is preferably set to 0 ° C., which is the lower limit of the guaranteed range of the CCD camera operation. When the set temperature is increased, the heater requires a larger amount of heat generation, so the life of the heater is shortened and the temperature difference between the CCD camera and the surroundings is increased, leading to damage to the CCD camera due to thermal strain. In addition, the heat easily passes through the heat insulating material and escapes to the surroundings, which causes adverse effects such as raising the environmental temperature of the place to be observed. Temperature control is facilitated by using a constantan wire or a manganin wire, which has a small resistance change in temperature. Use a wire with a diameter of 0.1 to 1.0 mm as the heater wire, and adjust the length so that the resistance value of the heater is 10 to 50Ω. Since it cannot be increased by more than 3 mm, it can be miniaturized, and it is convenient for the temperature control device because the output voltage and current are in an easy-to-handle range.

  Metal with high thermal conductivity (silver, gold, copper, aluminum or these metals) to uniformly transmit the heat generated by the heater for adjusting the temperature of the CCD camera to the temperature sensor (thermocouple or resistance thermometer) and the camera By arranging the foil or thin plate between the heater and the thermometer, heat can be efficiently and uniformly transferred. Furthermore, a temperature sensor is fixed to the optical signal conversion part of the CCD camera element with polyimide tape, a temperature sensor is included outside the temperature sensor, and a metal foil or a metal thin plate for improving heat conduction over the entire outer periphery of the CCD camera element is provided. The heater is wound around the entire circumference of the metal foil or the thin metal plate, and the heat insulating material is wound around the entire circumference of the heater. This is because the thermometer is cooled from the outside if the order of the heater and thermometer is reversed, the temperature indicated by the thermometer is lower than the actual temperature of the CCD camera, and the CCD camera is heated too much. This leads to damage. Further, the CCD camera element, the temperature sensor, the metal foil or metal thin plate, and the heater are in close contact with each other to improve heat conduction. Further, the heat insulating material is also closely attached to the outer periphery of the heater so that the heat of the heater does not escape to the outside.

  Since the CCD camera having a temperature control function according to the present invention can be made smaller than a CCD camera using a conventional heat insulating container, an object placed at a very low temperature can be observed through a narrow path. Furthermore, in an endoscope using an optical fiber, it is indispensable to fix a path for observation in advance, but in the CCD camera of the present invention, observation can be performed by changing the path as needed due to electrical wiring.

The cross-sectional schematic diagram of the CCD camera which operate | moves in the cryogenic environment which provided the temperature control function. A picture of a CCD camera operating in a cryogenic environment with a temperature control function. The example of the usage form of the CCD camera which operate | moves in the cryogenic environment which provided the temperature control function. A photograph of electrical wiring installed in a container cooled to 20K or less. A photograph of an electrical connector installed in a container cooled to 20K or less. A photograph of an electrical connector installed in a container cooled to 20K or less. Video obtained in a cryogenic environment when the temperature control function is not activated.

<Example 1>
FIG. 1 shows a schematic diagram of a cross section of a CCD camera operating in a cryogenic environment having a temperature control function. A Cernox resistance thermometer (Lake Shore) (2) adjacent to a CCD camera (300,000 pixels, operating temperature range: 0 to 40 ° C.) (1) installed at the end of a video cable with a diameter of 5 mm and a length of 3 m ) And wrap the CCD camera (1) and resistance thermometer (2) in a single layer with a 0.1 mm thick copper plate (width 40 mm) (3). An enamel-coated constantan wire having a diameter of 0.1 mm was spirally wound around the axis of the CCD camera as a heater (4) on the copper plate. At this time, the length of the constantan wire is adjusted so that the resistance value becomes 20Ω. And a fluororesin tape is wound twice as a heat insulating material (5) over the outer periphery of a heater (4).

FIG. 2 is a photograph when the heat insulating material (5) is not attached in the CCD camera operating in the cryogenic environment having the temperature control function shown in FIG. The temperature sensor, copper plate, and heater are fixed to the CCD camera and a signal transmission cable from the CCD camera with polyimide tape. When the fluororesin tape in the outermost layer of the CCD camera operating in a cryogenic environment equipped with this temperature control function is wound, the outer diameter is 9 mm.

FIG. 3 shows an example of usage of a CCD camera that operates in a cryogenic environment with a temperature control function. The image cable (13) and the temperature adjustment cable (15) of the CCD camera (11) to which the temperature control function is provided are combined into one parallel multi-core wire (12) with polyimide tape, and the temperature control function-added CCD camera (11) To the room temperature environment and connected to the CCD video monitor (14) and the temperature control device (16), respectively. The temperature of the CCD camera (11) was set by PID control so that the temperature of the CCD camera (11) was 273K regardless of the ambient temperature. The object (10) cooled to the cryogenic temperature to be observed was installed in the vacuum heat insulating container (17), and the temperature control function-provided CCD camera (11) was provided in the vacuum heat insulating container (17). The position reached about 10 mm from the object (10) cooled to the cryogenic temperature to be observed through the hole (18) having a diameter of 12 mm.

FIG. 4 is a photograph of a bundle of electrical wires installed in a container cooled to 20K or less, and was taken with a CCD camera operating in a cryogenic environment equipped with a temperature adjustment function in the usage mode shown in FIG. It can be seen that two or more of the wires that should originally be wired in a bundle are disconnected from the bundle and cut off in the middle. This indicates that an object placed in a cryogenic environment can be observed with a temperature adjustment function-added CCD camera.

<Example 2>
Subsequent to the observation of the bundle of electric wires in Example 1, the observation target was changed to an electric connector that was installed in the same container and cooled to 20K or less. FIG. 5 is a photograph of the electrical connector cooled to 20K or less. It can be seen that the air contained in a minute amount in the container is cooled to become a needle-like solid or the like and is piled on the electrical connector. This also indicates that the temperature control function-added CCD camera can change the observation target at any time.

<Example 3>
Continuing from the observation in Example 2, a stainless steel pipe was inserted into the cryogenic container simultaneously with the CCD camera, and helium gas was blown through the pipe to remove the solid air accumulated in the electrical connector.
FIG. 6 is a photograph after helium gas is blown to the electrical connector installed in the container cooled to 20K or less shown in FIG. A stainless steel pipe is visible on the left side of the picture in FIG. Also, the needle-like solid air disappears and the pin holes of the electrical connector can be clearly observed. With this temperature control function-equipped CCD camera, the work of blowing helium gas could be observed in real time, which greatly contributed to the improvement of work efficiency.

<Comparative Example 1>
If the temperature adjustment function is not activated under the same conditions as in the second embodiment, the image shown in FIG. 7 only appears on the CCD image monitor when the temperature of the CCD camera falls below 250K, and the electrical connector as shown in FIG. Could not be observed. This is because the element that replaces the light of the CCD camera with electrons works even at extremely low temperatures, but the electronic circuit for amplifying the electrons obtained from the light and transferring information to the video monitor is normal in a cryogenic environment. It is thought that it does not work.

  If the CCD camera with temperature adjustment function of the present invention is used, it can be applied to diagnoses such as defects in superconducting magnets that generate magnetic fields at extremely low temperatures and blockages in the supply and exhaust paths of vacuum insulation containers containing refrigerant. Occurrence and quick recovery are possible. In an endoscopic video camera using a CMOS instead of a CCD as an image sensor, an electronic circuit that replaces light with electrons operates even at an extremely low temperature, but amplifies the electrons obtained from the light and transfers information to a video monitor. The electronic circuit for this is considered not to operate in a cryogenic environment, but the present invention can be used to operate a CMOS camera in a cryogenic environment.

1: CCD camera 2: Thermometer 3: Copper plate 4: Heater 5: Insulating material 6: Cable for video and temperature control 10: Observation object placed in a cryogenic environment 11: CCD camera with temperature control function 12 : Cable for video and temperature control 13: Cable for video 14: CCD video monitor 15: Cable for temperature control 16: Equipment for temperature control 17: Vacuum insulation container 18: Hole provided in the vacuum insulation container

Claims (4)

A CCD camera for observing the state of an object placed at an extremely low temperature, in which a temperature sensor and a heater are installed in close contact with the optical signal conversion part of the CCD camera, and a heat insulating material is mounted outside the heater. The temperature of the CCD camera is detected by the temperature sensor, and power is applied to and controlled by the heater so as to keep the temperature of the CCD camera in the operating temperature range, and the ambient temperature of the CCD camera is extremely low. A CCD camera operating in a cryogenic environment characterized by having a function of maintaining the operating temperature range of the CCD camera.
2. The CCD camera operating in a cryogenic environment according to claim 1, wherein a metal foil or thin plate having high thermal conductivity is disposed between the CCD camera and the heater. CCD camera.
3. The CCD camera operating in a cryogenic environment according to claim 1, wherein the heater is a constantan wire or a manganin wire.
4. A CCD camera operating in a cryogenic environment according to claim 1, wherein the heat insulating material is made of fluororesin tape so as not to cause a visual field defect of the CCD camera. A CCD camera that operates in a cryogenic environment.