JPS6140125B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a cooled photoelectric conversion device, and in particular, in order to reduce the heat load due to heat conduction in an airtight container with a double tube structure, the inner tube is made of a bellows structure made of expandable and contractible metal. This invention relates to a cooled photoelectric conversion device.

A conventional cooled photoelectric conversion device is an airtight container with a double tube structure made of metal such as stainless steel, with a transmission window in a part of the outer tube and a photoelectric conversion element on the vacuum side wall of the inner tube facing the transmission window. (laser element or infrared detection element).
Fig. 1 shows such a conventional structure, and in the figure, 1 is an outer tube made of stainless steel, and 2 is an inner tube, and these two stainless steel cylinders constitute an airtight container with a dual structure. ing. 3
4 is a transparent window provided on the outside of the outer tube 1, and 4 is a cooling bottom provided on the upper part of the inner tube 2 facing the transparent window 3. For example, an infrared detection element 5 is soldered to the cooling bottom 4. There is. A voltage is applied to the infrared detecting element 5 from a lead terminal 6 via a lead wire 7. 8 is a shield for shielding radiant heat, and 9 is the cooling bottom 4.
This is a cooling head connected to the cold generation part of the cooler 10.

Here, the infrared detection element 5 produces an output corresponding to the amount of incident light, so infrared detectors using this are called photon detectors and have the advantage of fast reaction speed, but on the other hand, the temperature is much lower than room temperature. It has the property of not operating well unless it is cooled to a certain temperature. However, in a configuration in which the detection element faces upward as shown in Fig. 1, it cannot be cooled with liquid nitrogen or the like, so as an external cooling means, a cooling bottom 4 to which the infrared detection element 5 is soldered is connected to the cold generating part of the cooler 10. For example, the structure is such that a cooling head 9 made of copper or the like is pressed against the infrared sensing element 5 through the cooling bottom 4. However, when the cooling head 9 is rapidly cooled by the cooler 10, the cooling head 9 cools down. Due to the large expansion coefficient,
The shrinkage is large, and the cooling head 9 is separated from the cooling bottom 4, resulting in poor heat conduction, and the infrared detector cannot be cooled sufficiently, resulting in a disadvantage of deteriorating its performance.

The present invention has been made to solve the above-mentioned drawbacks, and focuses on using a double-structure inner tube made of metal as an expandable bellows to constantly press the cooling bottom and the cooling head into contact regardless of temperature changes. This is what I did. Briefly stated, the present invention provides a cooling type photoelectric conversion device having a double tube structure consisting of an outer tube provided with a transmission window and an inner tube provided with a photoelectric conversion element, in which the photoelectric conversion element is provided. An inner tube of the container is formed of a bellows, and the inner tube is in pressure contact with the cooling bottom,
It is also characterized by the arrangement of a cooling head connected to the cooler. Embodiments of the cooling type photoelectric conversion device according to the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a side cross-sectional view showing one embodiment of the present invention, in which the same parts as in the previous figure are given the same reference numerals. Reference numeral 11 is an inner tube made of a bellows made of stainless steel or the like, and reference numeral 12 is a set screw for fixing the cooling type photoelectric conversion device and the cooler 10.

In such a configuration, when the cooler 10 is attached to a cooling type photoelectric conversion device, it is fixed so that the inner pipe 11 made of bellows is in an extended state with the cooling head 9 and the cooling bottom 4 in contact with each other. Even if there is some expansion and contraction due to temperature changes, the expansion and contraction of the bellows 11 covers this expansion and contraction. Therefore, the contact surfaces between the cooling bottom 4 and the cooling head 9 are always kept in close contact with each other, resulting in good thermal conductivity.Furthermore, by forming the inner tube with a bellows, Since the surface length of the inner tube is 3 to 6 times that of a conventional inner tube, the thermal resistance when flowing into the cooling head 9 increases, reducing the heat load of the cooler, that is, the refrigeration capacity. That is clear.

On the other hand, it goes without saying that the finishing precision of the contact surface between the cooling bottom 4 and the cooling head 9 should be improved, and the materials of the cooling bottom 4 and the cooling head 9 should be selected from materials that have high thermal conductivity at low temperatures, and the bellows material should be It is preferable to use a material with a larger coefficient of thermal contraction than the head 9.

FIG. 3 is a sectional view of main parts showing another embodiment of the contact surface shape between the cooling bottom and the cooling head of the cooled photoelectric conversion device according to the present invention, and the same parts as in the previous figure are given the same reference numerals. There is.

In the figures, a and b indicate that the contact surface S between the cooling bottom 4 and the cooling head 9 has an uneven shape, and it is well known that such a shape increases the contact surface. In c, a plurality of protrusions are formed along the circumferential direction of the head of the cooling head 9, and notches that match the protrusions of the cooling head 9 are formed along the circumference on the back surface where the elements of the cooling bottom 4 are attached. The cooling head 9 is inserted into the cooling bottom 4 and rotated by 90 degrees or less in the circumferential direction to engage. When they are engaged in this way, they are in a tensioned state so that they are in pressure contact with the inner tube formed by the bellows, which increases the contact surface, speeds up the cooling of the element 5, and prevents it from separating due to vibrations and shocks. can.

In this embodiment, the infrared sensing element has been described in detail, but the present invention is applicable not only to infrared sensing elements but also to all types of airtight containers that require maintenance of low temperatures, such as laser elements.

As explained above, according to the cooled photoelectric conversion device to which the present invention is applied, by configuring the inner tube of the airtight container with a metal bellows, the heat load can be reduced and the heat generated between the cooling bottom and the cooling head can be reduced. Since it is possible to improve conduction as well as vibration resistance and impact resistance, it is expected to provide a high-quality cooled photoelectric conversion device.

[Brief explanation of the drawing]

FIG. 1 is a side cross-sectional view of a conventional cooled photoelectric conversion device, FIG. 2 is a side cross-sectional view showing an embodiment of a cooled photoelectric conversion device according to the present invention, and FIG. 3 is a side cross-sectional view showing an embodiment of a cooled photoelectric conversion device according to the present invention. FIG. 7 is a sectional view of a main part showing another embodiment of the shape of the contact surface between the cooling bottom and the cooling head of the converter. 1: Outer tube, 2: Inner tube, 3: Transmission window, 4: Cooling bottom, 5: Infrared detection element, 6: Lead terminal, 7: Lead wire, 8: Shield, 9: Cooling head, 10: Cooler, 11: Inner tube formed by bellows, 12: Set screw.

Claims (1)

[Scope of Claims] 1. A cooling type photoelectric conversion device with a double tube structure, consisting of an inner tube having a cooling bottom to which a photoelectric conversion element is attached, and an outer tube having a transmission window at a position facing the photoelectric conversion element. In the cooling type, the inner tube is composed of a bellows having elasticity, and a cooling head is disposed inside the inner tube in pressure contact with the cooling bottom and connected to the cooler. Photoelectric conversion device.