Grinding method for cubic prism assembly of infrared detector
By using a combination of protective tape and heat shrink tubing on the cubic prism assembly of the infrared detector, the protection problem during the cubic prism grinding process was solved, achieving efficient and low-cost cubic prism protection and easy disassembly and assembly operations, ensuring the optical performance and coplanarity requirements of the assembly.
Patent Information
- Application Number
- CN202511840145.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-08
- Publication Date
- 2026-03-06
AI Technical Summary
The existing infrared detector components are difficult to protect during the grinding process of cubic prisms, which can easily cause defects such as scratches and chipping, affecting the accuracy and reliability of the components. In addition, the protective tooling is complicated to disassemble, which affects production efficiency.
The protective structure uses a combination of protective tape and heat-shrink tubing. Through cutting and heat shrinking, multiple protective rings and caps are formed, combined with protective fiber filling, to prevent abrasive damage to the surface of the cubic prism and simplify the assembly and disassembly process.
It effectively protects the surface integrity of cubic prisms, prevents damage from grinding debris, simplifies the operation process, reduces costs, improves production efficiency, and ensures optical properties and coplanarity requirements.
Smart Images
Figure CN121607980A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for protecting optical elements, specifically to a method for grinding a cubic prism assembly of an infrared detector. Background Technology
[0002] Infrared technology was already being used in many fields during the 1940s, but its application only saw significant development in the late 1950s and early 1960s. With the rapid development of infrared technology, infrared thermal imaging technology has been increasingly widely applied in both military and civilian fields, expanding into weather forecasting, climate prediction, natural disaster and Earth environment monitoring, marine, aviation, navigation, agriculture, fisheries, and remote sensing, with its popularity continuing to rise. Infrared detector components are the core components of infrared imaging systems, and their performance and reliability play a crucial role in the entire system. Therefore, with the deepening application of infrared technology and the increasing scale of infrared detector components, users are placing increasingly higher demands on the accuracy and reliability of infrared components. High-precision imaging relies mainly on the high-precision assembly and adjustment of cubic prisms to achieve high-precision stitching of infrared detectors. When the detector is powered on, it converts high-precision mechanical signals into electrical signals, thereby achieving high-precision imaging.
[0003] See the structural schematic diagram of the existing infrared detector assembly. Figure 1 and Figure 2 It mainly consists of an infrared detector Dewar 2, a support frame (not shown in the figure), and three cubic prism assemblies 3. A Dewar cold head 11 is set below the infrared detector Dewar 2. The cubic prism 31 is made of K9 glass, with a chromium film plated on the surface of the glass body, and an aluminum film plated on the chromium surface. At the same time, the upper surface of the cubic prism 31 is plated with a butterfly-shaped photolithographic mark.
[0004] The infrared detector assembly places extremely high demands on the surface quality of the cubic prism. Under 10x microscopy, the surface must be free of scratches, chipping, or other defects. Particular strict requirements apply to the area near the butterfly-shaped photolithographic markings on the prism's upper surface; the markings must be undamaged, and the surrounding area must be free of any adhering substances or stains, otherwise it will affect the collinearity adjustment of the infrared detector assembly. Any scratches on the prism surface will render it unusable, and since the prism is a high-cost, high-labor-value component, its scrapping represents a significant waste.
[0005] Given the extremely high requirements for the appearance of the cubic prism in infrared detector components, the prism surface needs to be precisely protected during the grinding process to adjust its coplanarity. This protection is quite challenging, mainly due to the following aspects: 1) Since the prism surface is smooth, it must be tightly wrapped with the protective fixture to prevent damage during processing and grinding; 2) To facilitate the processing and grinding of the prism component, the area around the prism base should not be wrapped, otherwise it will cause processing difficulties and affect production efficiency; 3) During the assembly and adjustment of the infrared detector, the coplanarity of the upper surface of the prism and the upper surface of the detector chip needs to be repeatedly ground and tested, requiring multiple disassemblies of the protective fixture. Therefore, the protective fixture must be easy to disassemble, and damage to the prism's appearance must be avoided during disassembly. Summary of the Invention
[0006] The purpose of this invention is to solve the problem of the difficulty in protecting the cubic prism component during the grinding process in existing infrared detector assemblies, and to provide a grinding method for the cubic prism component of an infrared detector.
[0007] To achieve the above objectives, the technical solution provided by this invention is: A grinding method for an infrared detector cubic prism assembly, the infrared detector assembly including an infrared detector Dewar mounted on a mounting plate and three cubic prism assemblies; each cubic prism assembly includes a prism base and a cubic prism mounted on the prism base, and a detector chip is disposed within the infrared detector Dewar; the method is characterized by including the following steps: Step 1: Assemble the infrared detector assembly; Step 2: Obtain the coplanarity data of the upper surface of the three cubic prisms and the upper surface of the Dewar's detector chip of the infrared detector. If there are cubic prisms whose coplanarity data does not meet the preset requirements, remove the cubic prism assembly containing all cubic prisms whose coplanarity data does not meet the preset requirements from the mounting plate, and then proceed to Step 3. If the coplanarity data of each cubic prism and the Dewar's detector chip of the infrared detector meet the preset requirements, the grinding is complete. Step 3: Protect the cubic prism in the cubic prism assembly. Step 3.1: Cut protective tape according to the dimensions of the cubic prism. The width of the protective tape should be equal to the height of the cubic prism, and the length of the protective tape should be at least 2 to 3 times the circumference of the bottom surface of the cubic prism. Step 3.2: Clean the four sides and top surface of the cubic prism, and then tightly wrap the cut protective tape around the four sides of the cubic prism in 2 to 3 layers. Step 3.3: Prepare the first heat shrink tubing. The height of the first heat shrink tubing is 0.25 to 0.7 times the height of the cubic prism. Then, put the first heat shrink tubing on the four sides of the cubic prism, near the bottom, with the bottom surface flush with the bottom surface of the cubic prism. Step 3.4: Use a heat shrink gun to heat shrink the installed first heat shrink sleeve to form a protective collar, which is used to protect the lower part of the four sides of the cubic prism. Step 3.5: Prepare the second heat shrink tubing. The height of the second heat shrink tubing is 0.5 to 0.7 times the height of the cubic prism. Then, put the second heat shrink tubing on the four sides of the cubic prism, close to the top, so that the lower end face is on the outside of the upper end face of the first heat shrink tubing, and the upper end face is higher than the upper surface of the cubic prism, forming a redundant part. Step 3.6: Use a heat shrink gun to heat shrink the installed second heat shrink sleeve to form a protective cap, which is used to protect the upper part of the four sides of the cubic prism. Step 3.7: Fill the redundant part of the protective cap with protective fibers to protect the upper surface of the cubic prism. Step 4: Based on the deviation between the obtained coplanarity data and the preset requirement data, grind the lower surface of all prism bases in all cubic prism assemblies that have been protected according to the corresponding deviation. Then remove the protective cap and the filling protective fiber. The protective cap is reserved for later use, and the protective fiber is discarded. Step 5: Install all the ground cubic prism assemblies onto the mounting plate, and then obtain the coplanarity data of the upper surface of the three cubic prisms and the upper surface of the Dewar's detector chip of the infrared detector. If there are still cubic prisms whose coplanarity data does not meet the preset requirements, remove all cubic prism assemblies containing cubic prisms whose coplanarity data does not meet the preset requirements from the mounting plate, and then proceed to Step 6; if the coplanarity data of each cubic prism and the Dewar's detector chip of the infrared detector meet the preset requirements, then proceed to Step 7. Step 6: Place the reserved spare protective caps on the four sides of the cubic prism again, close to the top, so that the lower end face is on the outside of the upper end face of the first heat shrink tubing, and the upper end face is higher than the upper surface of the cubic prism, forming a redundant part; fill the redundant part of the protective cap with protective fiber, and then return to step 4. Step 7: Remove the protective rings and protective tape from the cube prisms in all cube prism assemblies and clean the cube prism assemblies. Step 8: Install all the cleaned cubic prism components onto the mounting plate to complete the grinding of the infrared detector cubic prism components.
[0008] Furthermore, in step 2, the coplanarity data includes the height difference between the upper surface of the cubic prism and the upper surface of the detector chip, as well as the flatness and attitude angle deviation of the upper surface of the cubic prism. The height difference is calculated using butterfly-shaped photomasks coated on the upper surface of both the cubic prism and the detector chip.
[0009] Furthermore, in step 3.3, the height of the first heat shrink tubing is 0.40 to 0.60 times the height of the cubic prism; In step 3.5, the height of the second heat shrink tubing is 0.55 to 0.65 times the height of the cubic prism.
[0010] Furthermore, in step 3.3, the height of the first heat shrink tubing is 0.50 times the height of the cubic prism; In step 3.5, the height of the second heat shrink tubing is 0.60 times the height of the cubic prism.
[0011] Further, step 7 specifically involves: removing the cubic prism assembly containing the protective sleeve and protective tape from the mounting plate, then immersing the cubic prism assembly in gasoline for 10 to 15 minutes, removing the protective sleeve; cleaning in an ultrasonic cleaner for a preset time to allow the protective tape to fall off, then replacing with clean cleaning fluid and continuing ultrasonic cleaning to remove any grinding metal debris that may be adhering to the cubic prism assembly.
[0012] Furthermore, the protective fiber is cotton.
[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. The infrared detector cubic prism assembly provided by the present invention has a simple protective structure, is easy to assemble and disassemble, and has low cost. After protection, it can prevent metal debris generated during grinding from damaging the side and top surfaces of the cubic prism, effectively ensuring the integrity of the optical properties of the cubic prism itself.
[0014] 2. The infrared detector cubic prism assembly provided by the present invention, in its protective measures, the combination of polyimide tape, protective sleeve, and protective cap, prevents the generation of the siphon effect and fundamentally prevents the polishing fluid from damaging the prism.
[0015] 3. The grinding method for the cubic prism assembly of the infrared detector provided by the present invention is simple to operate. During the test, only the cotton and protective cap need to be removed each time, without removing all the protective components, which saves manpower and resources. Moreover, the protective cap can be reused. Attached Figure Description
[0016] Figure 1 Schematic diagram of the infrared detector assembly Figure 1 ; Figure 2Schematic diagram of the infrared detector assembly Figure 2 ; Figure 3 This is a schematic diagram of a cubic prism assembly. Figure 4 This is a schematic diagram of the structure after protecting the cubic prism in step 3.7 of an embodiment of the present invention; The attached figures are labeled as follows: 1-Mounting plate; 11-Dewar cold head; 2-Infrared detector Dewar; 3-Cubic prism assembly; 31-Cubic prism; 32-Prism base; 301 - Protective tape, 302 - Protective collar, 303 - Protective cap, 304 - Protective fiber. Detailed Implementation
[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0018] A grinding method for an infrared detector cubic prism assembly, the infrared detector assembly including an infrared detector Dewar 2 and three cubic prism assemblies 3 mounted on a mounting plate 1; each cubic prism assembly 3 includes a prism base 32 and a cubic prism 31 mounted on the prism base 32, and a detector chip is disposed inside the infrared detector Dewar 2; characterized by the following steps: Step 1: Assemble the infrared detector assembly; Step 2: Obtain the coplanarity data of the upper surfaces of the three cubic prisms 31 and the upper surface of the detector chip inside the infrared detector Dewar 2. The coplanarity data includes the height difference between the upper surfaces of the cubic prisms 31 and the upper surfaces of the detector chip, as well as the flatness and attitude angle deviation of the upper surface of the cubic prisms 31. The height difference is calculated using butterfly-shaped photolithography marks deposited on both the upper surfaces of the cubic prisms 31 and the upper surfaces of the detector chip. If there are cubic prisms 31 whose coplanarity data does not meet the preset requirements, remove the cubic prism assembly 3 containing all cubic prisms 31 whose coplanarity data does not meet the preset requirements from the mounting plate 1, and then proceed to Step 3. If the coplanarity data of each cubic prism 31 and the detector chip inside the infrared detector Dewar 2 meet the preset requirements, the grinding is complete. Step 3: Protect the cubic prism 31 in the cubic prism assembly 3. Step 3.1: Cut protective tape 301 according to the size of cubic prism 31 (the cutting should be done under a microscope, the blade should be changed in time, and the tape should be kept clean during the cutting process). The width of protective tape 301 is equal to the height of cubic prism 31, and the length of protective tape 301 is at least 2 to 3 times the circumference of the bottom surface of cubic prism 31. Step 3.2: Clean the four sides and top surface of the cubic prism 31 (note that a hard brush should not be used for cleaning, otherwise it will scratch the prism surface. A soft brush with a suitable amount of cleaning solution should be used for cleaning). Then, tightly wrap the cut protective tape 301 around the four sides of the cubic prism 31, with 2 to 3 layers. Step 3.3: Prepare the first heat shrink tubing. The height of the first heat shrink tubing is 0.5 times the height of the cubic prism 31. Then, put the first heat shrink tubing on the four sides of the cubic prism 31 and close to the bottom. The bottom surface of the tubing is flush with the bottom surface of the cubic prism 31. Step 3.4: Use a heat shrink gun to heat shrink the installed first heat shrink sleeve to form a protective collar 302, which is used to protect the lower part of the four sides of the cubic prism 31. Step 3.5: Prepare the second heat shrink tubing. The height of the second heat shrink tubing is 0.6 times the height of the cubic prism 31. Then, put the second heat shrink tubing on the four sides of the cubic prism 31 and close to the top. Make sure that the lower end face is on the outside of the upper end face of the first heat shrink tubing and the upper end face is higher than the upper surface of the cubic prism 31, forming a redundant part. Step 3.6: Use a heat shrink gun to heat shrink the installed second heat shrink sleeve to form a protective cap 303, which is used to protect the upper part of the four sides of the cubic prism 31. Step 3.7: Fill the redundant part of the protective cap 303 with protective fiber 304 to protect the upper surface of the cubic prism 31. Step 4: Based on the deviation between the obtained coplanarity data and the preset requirement data, grind the lower surface of all prism bases 32 in all cubic prism assemblies 3 that have been protected according to the corresponding deviation. Then remove the protective cap 303 and the filling protective fiber 304. The protective cap 303 is reserved for later use, and the protective fiber 304 is discarded. Step 5: Install all the ground cubic prism assemblies 3 onto the mounting plate 1. Then, obtain the coplanarity data of the upper surface of the three cubic prisms 31 and the upper surface of the detector chip inside the infrared detector Dewar 2. If there are still cubic prisms 31 whose coplanarity data does not meet the preset requirements, remove all cubic prism assemblies 3 containing cubic prisms 31 whose coplanarity data does not meet the preset requirements from the mounting plate 1, and then proceed to step 6. If the coplanarity data of each cubic prism 31 and the detector chip inside the infrared detector Dewar 2 meets the preset requirements, then proceed to step 7. Step 6: Place the reserved spare protective caps 303 onto the four sides of the cubic prism 31 again, close to the top, so that the lower end face is on the outside of the upper end face of the first heat shrink tubing, and the upper end face is higher than the upper surface of the cubic prism 31, forming a redundant part; fill the redundant part of the protective caps 303 with protective fibers 304, and then return to step 4. Step 7: Remove the protective ring 302 and protective tape 301 from all cubic prism assemblies 31 and clean the cubic prism assembly 3; remove the cubic prism assembly 3 containing the cubic prism 31 with the protective ring 302 and protective tape 301 from the mounting plate 1, then soak the cubic prism assembly 3 in gasoline for 10-15 minutes, and remove the protective ring 302; clean in an ultrasonic cleaner for a preset time to allow the protective tape 301 to fall off, then replace with clean cleaning fluid (which can be anhydrous ethanol) and continue ultrasonic cleaning to remove any grinding metal debris that may be adhering to the cubic prism assembly 3.
[0019] Step 8: Install all the cleaned cubic prism components 3 onto the mounting plate 1 to complete the grinding of the infrared detector cubic prism components.
[0020] In this embodiment, the protective fiber 304 is cotton.
[0021] In steps 2 and 5 of this embodiment, the coplanarity data meets the requirements, meaning that the average height difference between the upper surfaces of the three cubic prisms 31 and the upper surface of the infrared detector is close to zero. The flatness of the upper surface of each cubic prism 31 and the surface of the detector must be extremely high, and the upper surfaces of all cubic prisms 31 must not have a significant tilt relative to the reference coordinate system.
[0022] After optimizing the protective fixtures and methods, no grinding fluid is adsorbed on the side of the cubic prism 31 after each grinding. Only the grinding fluid on the prism base 32 needs to be cleaned, and the protective cap can be removed to perform data measurement. There is no need to repeatedly clean and wash the surface of the cubic prism 31. At the same time, the protective fixtures can be disassembled without damage, which fundamentally ensures the quality of the surface of the cubic prism 31.
Claims
1. A grinding method of an infrared detector cube prism assembly, the infrared detector assembly comprising an infrared detector dewar (2) and three cube prism assemblies (3) arranged on a mounting plate (1); each of the cube prism assemblies (3) comprises a prism base (32) and a cube prism (31) arranged on the prism base (32), and a detector chip is arranged in the infrared detector dewar (2); characterized in that, The method comprises the following steps: Step 1, assembling the infrared detector assembly; Step 2, obtaining the coplanarity data of the upper surface of each cube prism (31) and the upper surface of the detector chip in the infrared detector Dewar (2), respectively, if there is a cube prism (31) whose coplanarity data does not meet the preset requirements, then remove the cube prism assembly (3) in which all the cube prisms (31) whose coplanarity data do not meet the preset requirements from the mounting plate (1), and then perform step 3; if the coplanarity data of each cube prism (31) and the detector chip in the infrared detector Dewar (2) all meet the preset requirements, then complete the grinding; Step 3, protecting the cube prisms (31) in the cube prism assembly (3) Step 3.1, according to the size of the cube prism (31), cutting the protective tape (301), wherein the width of the protective tape (301) is equal to the height of the cube prism (31), and the length of the protective tape (301) is at least 2-3 times the length of the bottom surface of the cube prism (31); Step 3.2, cleaning the four side surfaces and the upper surface of the cube prism (31), then tightly wrapping the cut protective tape (301) on the four side surfaces of the cube prism (31), and the wrapping layer is 2-3 layers; Step 3.3, preparing a first section of heat-shrinkable sleeve, the height of the first section of heat-shrinkable sleeve is 0.25-0.7 times the height of the cube prism (31), then sleeving the first section of heat-shrinkable sleeve on the four side surfaces of the cube prism (31) and close to the lower end position, and the lower end surface is flush with the bottom surface of the cube prism (31); Step 3.4, using a heat-shrink gun to heat-shrink the installed first heat-shrinkable sleeve as a whole to form a protective sleeve ring (302) for protecting the lower part of the four side surfaces of the cube prism (31); Step 3.5, preparing a second section of heat-shrinkable sleeve, the height of the second section of heat-shrinkable sleeve is 0.5-0.7 times the height of the cube prism (31), then sleeving the second section of heat-shrinkable sleeve on the four side surfaces of the cube prism (31) and close to the upper end position, and the lower end surface is sleeved outside the upper end surface of the first section of heat-shrinkable sleeve, and the upper end surface is higher than the upper surface of the cube prism (31) to form a redundant part; Step 3.6, using a heat-shrink gun to heat-shrink the installed second heat-shrinkable sleeve as a whole to form a protective cap (303) for protecting the upper part of the four side surfaces of the cube prism (31); Step 3.7, filling protective fiber (304) in the redundant part of the protective cap (303) for protecting the upper surface of the cube prism (31); Step 4, according to the deviation of the obtained coplanarity data from the preset requirement data, grinding the lower surface of all prism bases (32) in all cube prism assemblies (3) that have been protected according to the corresponding deviation, then removing the protective cap (303) and the filled protective fiber (304), wherein the protective cap (303) is reserved for future use, and the protective fiber (304) is discarded; Step 5, install all the finished grinding cubic prism assembly (3) to the mounting plate (1), and then get the coplanarity data of the upper surface of the three cubic prisms (31) and the upper surface of the detector chip in the infrared detector Dewar (2), if the coplanarity data of the cubic prism (31) still does not meet the preset requirements, remove the cubic prism assembly (3) from the mounting plate (1), and then execute step 6; if the coplanarity data of each cubic prism (31) and the detector chip in the infrared detector Dewar (2) meets the preset requirements, execute step 7; Step 6, reserve the protective cap (303) according to the second time, which is set on the four sides of the cubic prism (31) and close to the upper end position, and the lower end surface is set outside the upper end surface of the first section of the heat shrink sleeve, and the upper end surface is higher than the upper surface of the cubic prism (31), forming a redundant part; fill the protective fiber (304) in the redundant part of the protective cap (303), and then return to step 4; Step 7, remove the protective sleeve (302) and protective tape (301) from all cubic prisms (31) in the cubic prism assembly (3) and clean the cubic prism assembly (3); Step 8, install all the cleaned cubic prism assembly (3) to the mounting plate (1) to complete the grinding of the infrared detector cubic prism assembly.
2. The grinding method of the infrared detector cubic prism assembly according to claim 1, wherein: In step 2, the coplanarity data includes the height difference between the upper surface of the cubic prism (31) and the upper surface of the detector chip, as well as the flatness of the upper surface of the cubic prism (31) and the attitude angle deviation; Wherein the height difference is calculated by the butterfly-shaped photoetch marks plated on the upper surface of the cubic prism (31) and the upper surface of the detector chip.
3. The grinding method of the infrared detector cubic prism assembly according to claim 2, wherein: In step 3.3, the height of the first section of the heat shrink sleeve is 0.40~0.60 times the height of the cubic prism (31); In step 3.5, the height of the second section of the heat shrink sleeve is 0.55~0.65 times the height of the cubic prism (31).
4. The grinding method of the infrared detector cubic prism assembly according to claim 3, wherein: In step 3.3, the height of the first section of the heat shrink sleeve is 0.50 times the height of the cubic prism (31); In step 3.5, the height of the second section of the heat shrink sleeve is 0.60 times the height of the cubic prism (31).
5. The grinding method of the infrared detector cubic prism assembly according to claim 4, wherein: The step 7 is specifically: the cuboid prism assembly (3) where the cuboid prism (31) with the protective sleeve ring (302) and the protective tape (301) exists is detached from the mounting plate (1), then the cuboid prism assembly (3) is soaked in gasoline for 10 min to 15 min, and the protective sleeve ring (302) is removed; the protective tape (301) is removed after the cuboid prism assembly (3) is cleaned in an ultrasonic cleaning machine for a preset time, then clean cleaning liquid is replaced to continue ultrasonic cleaning, and the grinding metal debris possibly adhered to the cuboid prism assembly (3) is removed.
6. The grinding method of the cuboid prism assembly of the infrared detector according to claim 5, characterized in that: The protective fiber (304) is cotton.