An electrical signal feedthrough device for detector vacuum packaging and its production process

Abstract

The present invention relates to the technical field of electrical signal sealed penetration, and discloses an electrical signal feedthrough device for detector vacuum packaging and its production process; the electrical signal feedthrough device includes a flange sealed and installed on the detector, a refrigerator interface penetrating through the flange and communicating with the refrigerator, a vacuum interface penetrating through the flange and communicating with a vacuum source, at least one mounting hole opened on the flange, and a vacuum penetration member having the same number as the mounting holes and disposed in the mounting holes; the vacuum penetration member includes a signal electrically connected metal needle, a sintered glass wrapped outside the signal electrically connected metal needle, and a metal needle fixing block disposed around the sintered glass; the metal needle fixing block is hermetically connected to the hole wall of the mounting hole; it can meet the requirements of high-precision vacuum packaging of large target surface mosaic detectors.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical signal sealed penetration, and particularly relates to an electrical signal feedthrough device for detector vacuum packaging and its production process. Background Art

[0002] With the development of space science and astronomy, the demand for precision in detection projects is also increasing day by day. In order to develop more precise optoelectronic detection instruments, scientific-grade detectors such as CCD optoelectronic sensors, CMOS sensors, infrared InGaAs sensors, InSb sensors, and MCT sensors are required. Taking scientific-grade CCD (scientific-grade charge-coupled device) as an example, such sensors are usually very expensive, with dense, tiny, and highly sensitive pixels. At the same time, due to the increasing size of the target surface of scientific-grade cameras, a single CCD cannot meet the requirements of the target surface, and multiple CCDs need to be spliced. The multiple CCDs are linearly spliced or staggered in a mechanical manner to form an image plane. Such scientific-grade optoelectronic detection devices have very high sensitivity, and the imaging surface must be kept clean. At the same time, considering the dark current noise of the device, the detector needs to work in a low-temperature environment to reduce the dark current noise of the device. For example, for a CCD, the temperature needs to be reduced to -100°C to reduce the dark current to one-thousandth of an electron level to ensure that the detector has a sufficient signal-to-noise ratio to detect very weak signals. This also determines that the detector must work in a stable vacuum environment so that the detector can be isolated from heat exchange with the environment and the detector can be cooled.

[0003] Implementing the electrical signal extraction of multiple CCDs in a vacuum environment is a challenging task. Especially for a mosaic camera, after multiple CCDs are mosaicked, numerous electrical signals of the detector need to be extracted through vacuum penetration. Existing vacuum feedthrough connectors mostly use the method of glass sintering. Considering the plugging of connectors and the stability of connectors, the number of pins is limited, and it is only suitable for the feedthrough extraction of a single signal or a single detector. Once the number of electrical signals to be extracted increases, the system complexity and the requirements for the stability of electrical connections will increase. Generally, for a single detector package, the number of electrical signal penetrations is about 20 - 30. Once detector mosaicking is carried out, the number of electrical signal penetrations will increase exponentially or dozens of times. It becomes very difficult to manufacture a vacuum penetration part that can support a large number of penetration signals and at the same time meet the docking with detector signals. Therefore, multiple vacuum penetration parts need to be used. In this case, vacuum leakage may occur due to changes in vacuum pressure or environmental temperature. Additionally, when there are high-precision requirements for the main focus camera or the mounting flange of the vacuum penetration part, the accuracy of the mounting flange of the vacuum penetration part also needs to be ensured. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides an electrical signal feedthrough device for detector vacuum packaging and its production process.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] An electrical signal feedthrough device for detector vacuum packaging includes a flange sealed and installed on the detector, a refrigerator interface penetrating through the flange and communicating with a refrigerator, a vacuum interface penetrating through the flange and communicating with a vacuum source, at least one mounting hole opened on the flange, and a vacuum penetrator having the same number as the mounting holes and disposed in the mounting holes; the vacuum penetrator includes a signal electrically connected metal pin, a sintered glass wrapped outside the signal electrically connected metal pin, and a metal pin fixing block surrounding the sintered glass; the metal pin fixing block is hermetically connected to the hole wall of the mounting hole.

[0007] Furthermore, the metal pin fixing block and the signal electrically connected metal pin are combined by a glass sintering process; when the vacuum penetrator is disposed in the mounting hole, the metal pin fixing block is inserted into the mounting hole, and the metal pin fixing block is hermetically bonded to the inner wall of the mounting hole. Specifically, the metal pin fixing block is higher than the sintered glass; a glue injection groove is opened around the hole wall of the mounting hole, and when the vacuum penetrator is disposed in the mounting hole, the metal pin fixing block is inserted into the glue injection groove, and the metal pin fixing block is hermetically bonded to the inner wall of the glue injection groove.

[0008] Furthermore, it includes a stress relief groove opened around the hole wall of the mounting hole; the stress relief groove and the glue injection groove are distributed in a stepped manner, and the stress relief groove is located circumferentially outside the glue injection groove and higher than the glue injection groove.

[0009] Furthermore, it includes a vacuum gauge installed in the vacuum interface; the vacuum gauge is used to measure the vacuum degree inside the detector.

[0010] A production process of an electrical signal feedthrough device for detector vacuum packaging includes the following steps:

[0011] Step 1: Perform stress simulation on the flange and the stress relief groove on the flange under vacuum. When performing stress simulation on the stress relief groove, it should be considered: the influence of the stress relief groove on the deformation of the entire flange under vacuum, and the stress relief effect of the stress relief groove itself.

[0012] Step 2: The flange is processed with titanium alloy material, the signal electrically connected metal pin and the metal pin fixing block are processed with kovar alloy, and the signal electrically connected metal pin is gold-plated.

[0013] Step 3: The signal electrically connected metal pin and the metal pin fixing block are connected together by glass sintering to complete the processing of the vacuum penetrator.

[0014] Step 4: Weld the refrigerator interface and the vacuum interface onto the flange, and trim the flatness of the flange after welding;

[0015] Step 5: Bond the vacuum penetrator into the mounting hole of the flange using ASTM E595 glue;

[0016] Step 6: Use a vacuum leak detector to detect the vacuum leak rate of the electrical signal feedthrough device. Install the flange on the detector, and use a leak detection blind plate to conduct an overall vacuum pressure rise leak rate detection on the detector. The overall leak rate is less than 1E10-9 Pa·m 3 / s.

[0017] Compared with the prior art, the beneficial technical effects of the present invention are:

[0018] In the case of splicing a large number of detectors in the vacuum detector packaging, while ensuring the vacuum leak rate within a wide working temperature range and the position accuracy of the packaging flange, use a small vacuum penetrator to complete the vacuum feedthrough of more than 1000 electrical signals, achieving a contribution to the system leak rate of less than 1E10-9 Pa·m 3 / s, and introducing a stress relief groove to reduce the deformation effect of the vacuum on the sealing structure, greatly reducing the influence of stress on the vacuum feedthrough part.

[0019] Specifically, the electrical signal feedthrough device and its production process in the present invention have the following advantages:

[0020] 1. Ensure the vacuum leak rate;

[0021] 2. The flange has a large area and can penetrate a large number of electrical signals;

[0022] 3. Low cost;

[0023] 4. Ensure the flatness of the flange mounting surface;

[0024] 5. Adapt to a wide temperature range, from low temperature -40°C to 40°C; BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is the overall structure diagram of the electrical signal feedthrough device of the present invention;

[0026] Figure 2 is the structural schematic diagram of the vacuum penetrator of the present invention;

[0027] Figure 3 is the top view of the vacuum penetrator of the present invention;

[0028] Figure 4 is Figure 3 the cross-sectional view taken at A-A in

[0029] Figure 5This is a schematic diagram of the installation of the vacuum penetration component of the present invention on a flange. Detailed implementation manner

[0030] The following will give a detailed description of a preferred implementation manner of the present invention with reference to the accompanying drawings.

[0031] As Figure 1 shown, the present invention provides an electrical signal feedthrough device for detector vacuum packaging and its production process. The electrical signal feedthrough device includes a flange 3, a refrigerator interface 1, a vacuum interface 2, and a plurality of small vacuum penetration components 4.

[0032] The refrigerator interface 1 is an interface for providing refrigeration for the detector. For large target area detectors, refrigeration generally uses a refrigerator, and the cold head of the refrigerator needs to enter the cavity of the detector vacuum packaging through the refrigerator interface 1. The size of the refrigerator interface 1 is determined by the specific requirements of the refrigerator. The refrigerator interface 1 is combined with the flange 3 by welding.

[0033] The vacuum interface 2 is an interface in the detector vacuum packaging cavity for obtaining, measuring, and maintaining vacuum. The vacuum interface 2 can use a vacuum standard interface CF port, and devices such as a vacuum gauge and a vacuum pump can be installed on the vacuum interface 2. The vacuum interface 2 is combined with the flange 3 by welding.

[0034] As Figure 5 shown, the flange 3 is processed from materials with low thermal deformation, such as titanium alloy, invar steel, etc., and the processing accuracy reaches the micron level. Considering the stress influence of the deformation of the flange 3 in vacuum on the vacuum penetration component 4, a stress relief groove 302 is designed around each vacuum penetration component 4 to ensure that the vacuum leakage rate will not increase due to the stress influence of the deformation of the flange 3 in vacuum.

[0035] As Figure 2 , Figure 3 , and Figure 4 , the vacuum penetration component 4 is composed of a signal electrical connection metal pin 401, a metal pin fixing block 402, and sintered glass 403. The combination of the signal electrical connection metal pin 401 and the metal pin fixing block 402 uses glass sintering. Considering the working environment of the camera (-20°C - 40°C), thermal matching is required in the design; the thermal expansion coefficient of the glass is 7.1 ppm / K, and the materials of the signal electrical connection metal pin 401 and the metal pin fixing block 402 are selected as kovar alloy, and the thermal expansion coefficient of the kovar alloy is 5.1 ppm / K. At the same time, considering good contact and welding, the signal electrical connection metal pin 401 is gold-plated.

[0036] As Figure 5As shown in the figure, the vacuum penetration part 4 is the weakest part in the entire flange 3 in terms of vacuum, and it is prone to deformation, resulting in an increase in the leakage rate. In addition to designing a stress relief groove 302 on the flange 3, the cross-sections of the metal pin fixing block 402 and the sintered glass 403 are in a Π shape, causing the stress at the installation surface of the vacuum penetration part 4 and the flange 3 to turn, ensuring the leakage rate.

[0037] The entire processing and installation process is as follows:

[0038] Step 1: Design of each component:

[0039] Design the flange 3, the refrigerator interface 1, the vacuum interface 2, and the vacuum penetration part 4, and conduct stress simulation on the flange 3 under vacuum. When conducting stress simulation on the stress relief groove 302 around the vacuum penetration part 4, two points need to be considered in determining the depth of the stress relief groove 302: one is that if the stress relief groove 302 is too deep, the deformation of the entire flange 3 under vacuum will become larger, and the strain at the bonding position will also be larger; the other is that if the stress relief groove 302 is too shallow, the stress relief effect will be too small. The depth of the stress relief groove 302 can be determined through ANSYS simulation. The refrigerator interface 1 is designed according to the size of the refrigerator cold head. One end of the vacuum interface 2 is welded to the flange 3, and the other end uses a standard CF port.

[0040] Step 2: Processing of each component:

[0041] This includes the processing of the signal electrical connection metal pin 401, the metal pin fixing block 402, the flange 3, the refrigerator interface 1, and the vacuum interface 2. The flange 3 is processed with a titanium alloy material whose thermal expansion coefficient is close to that of hard glass and has sufficient strength; the signal electrical connection metal pin 401 and the metal pin fixing block 402 are processed with a kovar alloy whose thermal expansion coefficient is close to that of hard glass; considering good contact and welding, the signal electrical connection metal pin 401 is gold-plated.

[0042] Step 3: Glass sintering of the vacuum penetration part 4:

[0043] According to the design drawing of the vacuum penetration part 4, conduct glass sintering of the signal electrical connection metal pin 401 and the metal pin fixing block 402 to complete the processing of the vacuum penetration part 4.

[0044] Step 4: Welding and processing of the flange 3 assembly:

[0045] Weld the vacuum interface 2 and the refrigerator interface 1 on the flange 3. Since welding will cause deformation of the flange 3 surface, after welding is completed, the flange 3 surface is finely machined to meet the index requirements.

[0046] Step 5: Installation of the vacuum penetration part 4:

[0047] In order not to affect the position accuracy of the flange 3 and avoid the influence of the welding high temperature on the vacuum penetrator 4, the installation between the vacuum penetrator 4 and the flange 3 adopts the scheme of bonding with a high-strength adhesive that meets the NASA low outgassing standard ASTM E595, and at the same time, it also avoids the influence of the welding high temperature on the deformation of the flange 3.

[0048] Step Six, Vacuum Leak Rate Detection:

[0049] For the flange 3 that has completed the above steps, a vacuum leak detector is used to detect the vacuum leak rate, and a leak detection blind plate is used to detect the overall leak rate during vacuum pressure rise. The overall leak rate is less than 1E-10 Pa·m 3 / s.

[0050] In the case where the imaging surface of the detector is very large and the number of electrical signal feedthroughs is very large, the present invention does not affect the detector vacuum sealing system, can ensure the signal quality and electrical connection stability between the detector and the electronic device, and at the same time does not affect the position accuracy of the detector package flange. It can adapt to a wide temperature working range and achieve more than 1000 electrical signal vacuum feedthroughs, and can meet the requirements of high-precision vacuum packaging for large target surface mosaic detectors.

[0051] Embodiment

[0052] As Figure 1 shown, the electrical signal feedthrough device in the embodiment of the present invention includes two cryocooler interfaces 1, four vacuum interfaces 2, one flange 3, and fourteen vacuum penetrators 4. Among them, the vacuum interfaces 2 and the cryocooler interfaces 1 are welded to the flange 3, and the vacuum penetrators 4 are adhesively bonded to the flange 3 with a high-strength vacuum adhesive. The high-strength low outgassing adhesive uses epoxy resin, and through the special design of the stress relief groove 302 and the vacuum penetrator 4, it can adapt to a wide temperature range.

[0053] In the embodiment of the present invention, the number of signal electrical connection metal pins 401 is 116 pins, and 14 vacuum penetrators 4 can complete the penetration of 1624 electrical signals.

[0054] In the embodiment of the present invention, an installation hole 303 for installing the vacuum penetrator 4 is designed on the flange 3. A glue filling groove 301 for bonding with a vacuum sealing high-strength adhesive is designed on the outer circumference of the installation hole 303, and a stress relief groove 302 for releasing the vacuum pressure of the vacuum penetrator 4. The installation hole 303 cooperates with the vacuum penetrator 4 to achieve vacuum sealing.

[0055] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention, and any reference signs in the claims should not be regarded as limiting the claims involved.

[0056] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment only contains an independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An electrical signal feedthrough device for the vacuum packaging of a detector, characterized in that, It includes a flange hermetically installed on the detector, a refrigerator interface penetrating through the flange and communicating with the refrigerator, a vacuum interface penetrating through the flange and communicating with the vacuum source, at least one mounting hole opened on the flange, and a vacuum penetrator having the same number as the mounting holes and disposed in the mounting holes; the vacuum penetrator includes a signal electrically connecting metal pin, a sintered glass wrapped outside the signal electrically connecting metal pin, and a metal pin fixing block surrounding the sintered glass; the metal pin fixing block is hermetically connected to the hole wall of the mounting hole; It includes a glue filling groove opened around the hole wall of the mounting hole and a stress relief groove opened around the hole wall of the mounting hole; the stress relief groove and the glue filling groove are distributed in a stepped manner, and the stress relief groove is located circumferentially outside the glue filling groove and higher than the glue filling groove; The flange is processed from titanium alloy material, and the signal electrically connecting metal pin and the metal pin fixing block are processed from kovar alloy.

2. The electrical signal feedthrough device for detector vacuum packaging according to claim 1, characterized in that: The metal pin fixing block and the signal electrically connecting metal pin are combined by a glass sintering process; when the vacuum penetrator is disposed in the mounting hole, the metal pin fixing block is inserted into the mounting hole, and the metal pin fixing block is hermetically bonded to the inner wall of the mounting hole.

3. The electrical signal feedthrough device for detector vacuum packaging according to claim 1, wherein: It includes a vacuum gauge installed in the vacuum interface; the vacuum gauge is used to measure the vacuum degree inside the detector.

4. A production process of an electrical signal feedthrough device for vacuum packaging of a detector according to any one of claims 1-3, comprising the following steps: Step 1: Perform stress simulation on the flange and the stress relief groove on the flange under vacuum. When performing stress simulation on the stress relief groove, the following should be considered: the influence of the stress relief groove on the deformation of the entire flange under vacuum, and the stress relief effect of the stress relief groove itself; Step 2: The flange is processed from titanium alloy material, the signal electrically connecting metal pin and the metal pin fixing block are processed from kovar alloy, and the signal electrically connecting metal pin is subjected to gold plating treatment; Step 3: The signal electrically connecting metal pin and the metal pin fixing block are connected together by a glass sintering method to complete the processing of the vacuum penetrator; Step 4: Weld the refrigerator interface and the vacuum interface on the flange, and trim the flatness of the flange after welding; Step 5: Bond the vacuum penetrator in the mounting hole of the flange with ASTM E595 glue; Step 6: Use a vacuum leak detector to detect the vacuum leak rate of the electrical signal feedthrough device. Install the flange on the detector and use a leak detection blind plate to conduct an overall leak rate detection of the detector for vacuum pressure boost. The overall leak rate is less than 1E-10 Pa·m 3 / s.

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