Fast-start infrared detector

Abstract

The present invention provides a rapid-start infrared detector comprising: a Dewar window, a cold screen, an infrared chip, a mounting substrate, a base plate, a Dewar body, a Dewar cold finger, a Dewar inner tube seat, a throttling cooler mounting base, a throttling cooler base, a finned tube, and a filter. The Dewar inner tube seat is fixed to the throttling cooler mounting base, the lower end of the Dewar body is fixed to the Dewar inner tube seat, the lower end of the Dewar window is fixed to the upper end of the Dewar body, the Dewar cold finger is fixed to the Dewar inner tube seat inside the Dewar body, the base plate is fixed to the upper end of the Dewar cold finger, the mounting substrate is fixed on the base plate inside the cold screen, the infrared chip is fixed on the mounting substrate, the throttling cooler base is installed inside the Dewar cold finger and extends out of the detector, the finned tube is wound around the outer wall of the throttling cooler base inside the Dewar cold finger, the mounting substrate is filled with microchannels, one end of the throttling tube passes through the base plate and is connected to the microchannel inlet, the other end is connected to the upper end of the finned tube, and the microchannel outlet is opened on the base plate within the space formed by the base plate and the Dewar cold finger.

Description

Technical Field

[0001] This invention relates to an infrared detector packaging structure, belonging to the field of infrared detection technology. Specifically, it develops a packaging structure that reduces interface thermal resistance and utilizes a throttling cooler integrated with a Dewar radiator to provide cooling to the infrared detector chip, enabling the chip to quickly reach its low-temperature operating temperature. Background Technology

[0002] In existing technologies, rapid-start infrared detectors typically employ a throttling cooler to cool the infrared detector chip. A throttling cooler generally consists of an inlet port, a finned tube heat exchanger, and a throttling orifice. It uses high-pressure, high-purity gas as the refrigerant, enabling the focal plane detector assembly to quickly reach its operating temperature and continuously providing low-temperature operating conditions. The principle is based on the Joule-Thomson effect; through a counter-current heat exchanger, the throttled gas pre-cools the incoming high-temperature gas, ultimately reaching the boiling point of the refrigerant, which is the operating temperature of the detector assembly.

[0003] The existing throttling cooled infrared detector structure consists of a throttling cooler, a vacuum Dewar shell, a cold finger, an infrared detector chip, a cold screen, and an optical window.

[0004] During operation, high-pressure working gas enters the throttling cooler. After being throttled and cooled, the gas is sprayed onto the lower surface of the Dewar cold platform substrate. The cooling effect is transferred to the chip through heat conduction, gradually lowering its temperature to the operating temperature. Simultaneously, low-temperature gas flows along the gap between the cold fingers and the throttling cooler base to pre-cool the high-pressure intake gas, ultimately liquefying the working gas and bringing the infrared detector chip to a lower operating temperature. The vacuum Dewar shell provides a vacuum environment for the infrared detector chip to maintain low temperature and reduce heat loss. The cold shield reduces stray radiation from the outside, ensuring the infrared detector chip receives target radiation. The optical window receives external light signals, providing a signal source for the infrared detector chip.

[0005] Existing infrared detectors typically involve separate fabrication and re-integration of the cooler and Dewar package. When the detector is operating, the throttling cooler's refrigerant can only reach the lower surface of the cold platform substrate. The cooling capacity needs to be conducted through multiple interfaces to reach the chip. The cooling capacity is conducted from the Dewar substrate to the chip through substrate adhesive, then through mounting substrate and chip adhesive. However, adhesive is usually a poor conductor of heat. Currently used adhesives have a thermal conductivity of less than 1 W / mk, while the thermal conductivity of the substrate metal and mounting substrate is usually tens or even hundreds of W / mk. The adhesive interface is a major factor affecting the startup time of the infrared detector. An additional layer of adhesive interface seriously affects the overall thermal conduction rate of the structure, which is not conducive to the rapid startup of the infrared detector. Summary of the Invention

[0006] The purpose of this invention is to provide a fast-start infrared detector packaging structure, which adopts an integrated Dewar throttling cooler packaging design. The finned tube of the cooler is connected to the opening of the Dewar substrate, and the substrate is welded to the mounting substrate. The mounting substrate has microchannels processed inside. The high-pressure cooling gas working fluid enters the microchannels embedded in the substrate through the opening of the substrate and acts directly on the substrate to achieve rapid cooling of the infrared chip, thus solving the problem of long start-up time of infrared detectors in the prior art.

[0007] To achieve the purpose of this invention, the following technical solution is adopted:

[0008] This invention discloses a fast-start infrared detector, comprising: a Dewar window, a cold shield, an infrared chip, a mounting substrate, a base plate, a Dewar body, a Dewar cold finger, a Dewar inner tube socket, a throttling cooler mounting base, a throttling cooler base, a finned tube, and a filter. The Dewar inner tube socket is fixed to the throttling cooler mounting base. The lower end of the Dewar body is fixed to the Dewar inner tube socket. The lower end of the Dewar window is fixed to the upper end of the Dewar body. An optical window is formed at the upper end of the Dewar window. The cold shield, infrared chip, mounting substrate, base plate, Dewar cold finger, finned tube, and filter are installed within the vacuum space formed by the Dewar window, Dewar body, and Dewar inner tube socket. The Dewar cold finger is fixed to the Dewar inner tube socket inside the Dewar body. The base plate is fixed to the upper end of the Dewar cold finger, the cold screen is fixed to the upper end of the base plate, the loading substrate is fixed on the base plate inside the cold screen, the infrared chip is fixed on the loading substrate, the filter is installed at the upper end of the cold screen, the throttling cooler base is installed inside the Dewar cold finger and passes through the inner tube seat of the Dewar and the throttling cooler mounting seat, and the infrared detector with fast start extends out. The finned tube is wrapped around the outer wall of the throttling cooler base inside the Dewar cold finger. Among them, the loading substrate is full of microchannels. One end of the throttling tube passes through the base plate and is connected to the microchannel air inlet. The other end is connected to the upper end of the finned tube. The diameter of the throttling tube is smaller than the diameter of the finned tube. The microchannel air outlet is opened on the base plate in the space enclosed by the base plate and the Dewar cold finger.

[0009] The present invention provides a fast-start infrared detector, wherein the loading substrate is a multilayer ceramic substrate.

[0010] The present invention provides a fast-start infrared detector, wherein the mounting substrate is soldered to a base plate using solder.

[0011] The rapid-start infrared detector of the present invention, wherein the diameter of the microchannel is 0.1 mm to 1 mm.

[0012] The fast-start infrared detector of the present invention has the following advantages:

[0013] 1. By employing microchannel technology within the substrate, the cooling distance is shortened, while significantly reducing thermal resistance. The microchannels increase the residence time of the refrigerant within the substrate, thus reducing cooling loss.

[0014] 2. The use of brazing technology between the base plate and the loading base plate ensures the airtightness and reliability of the connection.

[0015] 3. A metal base plate with openings is used to connect with the throttling orifice of the throttling cooler to ensure machinability and reliability.

[0016] 4. The infrared detector of the present invention adopts an integrated design of Dewar throttling cooler, which greatly reduces the thermal resistance of the infrared detector and improves the cooling start-up time of the detector. Attached Figure Description

[0017] Figure 1 This is a front cross-sectional schematic diagram of the fast-start infrared detector of the present invention;

[0018] Figure 2 This is a three-dimensional schematic diagram of the fast-start infrared detector of the present invention.

[0019] exist Figure 1 and Figure 2 In the diagram, 1 is the optical window; 2 is the Dewar window; 3 is the cold shield; 4 is the infrared chip; 5 is the mounting substrate; 6 is the solder; 7 is the base plate; 8 is the Dewar body; 9 is the microchannel outlet; 10 is the microchannel; 11 is the Dewar cold finger; 12 is the Dewar inner tube seat; 13 is the throttling cooler mounting base; 14 is the throttling cooler base; 15 is the finned tube; 16 is the microchannel inlet; 17 is the filter; and 18 is the throttling tube. Detailed Implementation

[0020] like Figure 1 and Figure 2As shown, the rapid-start infrared detector of the present invention includes: a Dewar window 2, a cold shield 3, an infrared chip 4, a mounting substrate 5, a base plate 7, a Dewar body 8, a Dewar cold finger 11, a Dewar inner tube seat 12, a throttling cooler mounting base 13, a throttling cooler base 14, a finned tube 15, and a filter 17. The Dewar inner tube seat 12 is fixed on the throttling cooler mounting base 13. The lower end of the Dewar body 8 is fixed on the Dewar inner tube seat 12. The lower end of the Dewar window 2 is fixed on the upper end of the Dewar body 8. An optical window 1 is opened at the upper end of the Dewar window 2. The cold shield 3, the infrared chip 4, and the mounting substrate are installed in the vacuum space formed by the Dewar window 2, the Dewar body 8, and the Dewar inner tube seat 12. The system comprises a plate 5, a base plate 7, a Dewar cold finger 11, a finned tube 15, and a filter 17. The Dewar cold finger 11 is fixed to the inner tube seat 12 inside the Dewar body 8. The base plate 7 is fixed to the upper end of the Dewar cold finger 11. The cold screen 3 is fixed to the upper end of the base plate 7. The mounting substrate 5 is soldered to the base plate 7 using solder 6. The mounting substrate 5 is a multilayer ceramic substrate. The infrared chip 4 is fixed to the mounting substrate 5. A filter 17 is mounted on the upper end of the cold screen 3. A throttling cooler base 14 is installed inside the Dewar cold finger 11 and passes through the inner tube seat 12 and the throttling cooler mounting base 13, extending out as a fast-start infrared detector. The finned tube 15 is wound around the outer wall of the throttling cooler base 14 inside the Dewar cold finger 11. The mounting substrate 5 contains numerous microchannels 10, each with a diameter of 0.1 mm to 1 mm. One end of the throttle tube 18 passes through the base plate 7 and is connected to the micro-channel air inlet 16, while the other end is connected to the upper end of the finned tube 15. The diameter of the throttle tube 18 is smaller than the diameter of the finned tube 15. The micro-channel air outlet 9 is located on the base plate 7 within the space enclosed by the base plate 7 and the Dewar cold finger 11.

[0021] The above is merely one embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A fast-start infrared detector, comprising: The components include a Dewar window (2), a cold shield (3), an infrared chip (4), a mounting substrate (5), a base plate (7), a Dewar body (8), a Dewar cold finger (11), a Dewar inner tube seat (12), a throttling cooler mounting base (13), a throttling cooler base (14), a finned tube (15), and a filter (17). The Dewar inner tube seat (12) is fixed on the throttling cooler mounting base (13), and the lower end of the Dewar body (8) is fixed on the Dewar inner tube seat (12). The Dewar window (2) is located below... The end is fixed to the upper end of the Dewar body (8). An optical window (1) is opened at the upper end of the Dewar window (2). A cold screen (3), an infrared chip (4), a mounting substrate (5), a base plate (7), a Dewar cold finger (11), a rib tube (15), and a filter (17) are installed in the vacuum space formed by the Dewar window (2), the Dewar body (8), and the Dewar inner tube seat (12). The Dewar cold finger (11) is fixed to the Dewar inner tube seat (12) inside the Dewar body (8). The base plate (7) is fixed to the upper end of the Dewar body (8). The upper end of the Dewar cold finger (11) has a cold screen (3) fixed to the upper end of the base plate (7). A mounting substrate (5) is fixed on the base plate (7) inside the cold screen (3). An infrared chip (4) is fixed on the mounting substrate (5). A filter (17) is installed at the upper end of the cold screen (3). The throttling cooler base (14) is installed inside the Dewar cold finger (11) and passes through the inner tube seat (12) of the Dewar and the throttling cooler mounting seat (13). A fast-start infrared detector extends out. A finned tube (15) is wound around the Dewar cold finger. The outer wall of the throttling cooler base (14) inside the cooling finger (11) is characterized by: having microchannels (10) arranged in the loading base plate (5), one end of the throttling tube (18) passing through the base plate (7) and connected to the microchannel air inlet (16), and the other end connected to the upper end of the finned tube (15), the diameter of the throttling tube (18) being smaller than the diameter of the finned tube (15), and the microchannel air outlet (9) opening on the base plate (7) within the space enclosed by the base plate (7) and the cooling finger (11).

2. The fast-start infrared detector as described in claim 1, characterized in that: The loading substrate (5) is a multilayer ceramic substrate.

3. The fast-start infrared detector as described in claim 2, characterized in that: The loading substrate (5) is soldered onto the base plate (7) using solder (6).

4. The fast-start infrared detector as described in claim 3, characterized in that: The diameter of the microchannel (10) is 0.1 mm to 1 mm.

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