Processing method of chalcogenide glass equal-thickness lens

Abstract

The invention relates to a chalcogenide glass equal-thickness lens processing method, belongs to the technical field of optical processing, and solves the problems of poor processing surface quality, complex operation, non-uniform stress of glass during polishing and poor surface defect grade of chalcogenide glass materials in the prior art. A chalcogenide glass equal-thickness lens processing method comprises the following steps of 1, rough grinding, wherein the two faces of a lens are manually ground, and the edge thickness difference of the lens is controlled to be smaller than or equal to 0.02 mm; step 2, polishing: polishing the coarsely ground lens in three stages, wherein polishing agents selected in the three stages are W1 aluminum oxide polishing powder, W0.3 aluminum oxide polishing powder and a W0.3 diamond solution in sequence; 3, centering and edging are carried out, wherein the center deviation of the lens is corrected to be smaller than 0.01 mm through a meter reading method; 4, under-disc polishing is conducted, specifically, a polishing mold and a clamping tool are applied to polish the two faces of the part, and scratches on the surface of the part are removed; and 5, vacuum coating: coating antireflection films on the two surfaces of the lens. And high-quality and high-precision processing of the chalcogenide glass equal-thickness lens is realized.

Description

Technical Field

[0001] The invention relates to the technical field of optical processing, and in particular to a method for processing thick lenses such as chalcogenide glass. Background Art

[0002] Chalcogenide glass is an infrared optical material with VIA group elements S, Se, and Te as its main components. It has a high transmittance between 1 and 14 μm and a small thermal coefficient (about one-fifth of Ge single crystal, i.e. 9×10 -7 / ℃), wide spectrum transmittance, suitable for compression molding and large-diameter preparation (maximum diameter can reach more than 140mm), etc.

[0003] There are various processing methods for chalcogenide glass optical components. Combined with the processing quantity and difficulty, the main processing forms are molding, high-efficiency processing and traditional classical processing. When processing small batches of chalcogenide glass parts, if the molding process is used, the manufacturing cost of the corresponding products will be greatly increased due to the high cost of manufacturing the molding mold. In addition, the optical properties of the material may also change during molding. However, if high-efficiency processing or traditional processing is used, the parts can be processed based on the stable optical properties of the material and the requirements of the optical indicators of the parts. Summary of the invention

[0004] In view of the above analysis, an embodiment of the present invention aims to provide a method for processing thick lenses made of chalcogenide glass, so as to solve at least one of the problems of poor surface quality, complicated operation, uneven force on the glass during polishing, poor grade of surface defects, and difficulty in controlling center deviation in existing chalcogenide glass material processing.

[0005] The embodiment of the present invention provides a method for processing a chalcogenide glass isothick lens, comprising the following steps:

[0006] Step 1, rough grinding: manually grind both sides of the lens, and control the thickness difference of the lens edge to within 0.02mm;

[0007] Step 2, polishing: polishing the roughly ground lens in three stages, the polishing agents used in the three stages are: W1 aluminum oxide polishing powder, W0.3 aluminum oxide polishing powder, W0.3 diamond solution;

[0008] Step 3: Centering and edge grinding: Use the table method to correct the lens center deviation <0.01mm and complete the edge grinding of the parts;

[0009] Step 4: Polishing under the plate: Use the polishing die and clamping tooling to polish both sides of the part to remove scratches on the surface of the part;

[0010] Step 5: Vacuum coating: Anti-reflection film is coated on both sides of the lens.

[0011] Furthermore, the rough-ground lens is polished in three stages as described in step 2, including rough polishing, fine polishing and repair polishing;

[0012] Specifically, the rough polishing stage includes the following steps:

[0013] S101, cleaning the roughly ground lens, pasting it on a polishing film to complete the mounting, and then placing it on a polishing mold coated with W1 alumina polishing powder, adjusting the position so that the surface of the lens fits the surface of the polishing mold;

[0014] S102, turn on the polishing machine, rotate the polishing mold, and perform rough polishing. The polishing time is 4 to 5 hours. Control the surface shape of the part within 5 apertures and clean the lens.

[0015] Furthermore, the fine polishing stage comprises the following steps:

[0016] S201, placing the roughly polished and cleaned lens on a polishing mold, and adding W0.3 aluminum oxide polishing liquid;

[0017] S202, turn on the polishing machine, rotate the polishing mold, and perform fine polishing. The polishing time is 4 to 5 hours. The surface shape of the part is controlled to be within 5 apertures, the surface roughness is Ra0.012um, and the number of scratches within a width of 0.07mm is not more than 10. Clean the lens.

[0018] Specifically, the polishing stage includes the following steps:

[0019] S301, after replacing the polishing mold, place the finely polished and cleaned lens on the polishing mold, and use a diamond solution with a particle size of W0.3 as a polishing agent;

[0020] S302, turn on the polishing machine, rotate the polishing mold, and perform repair polishing. The repair polishing time is 15 to 20 minutes. The surface shape of the part is controlled within 5 apertures, the surface roughness is Ra0.012um, and the surface defects are within Grade V.

[0021] It should be noted that during the three stages of rough polishing, fine polishing and repair polishing, the main shaft speed of the polishing machine is controlled at 40r / min-50r / min, the swing shaft speed is controlled at 30r / min-40r / min, and the load is 9-10N.

[0022] It is worth noting that the polishing mold used in the rough polishing and fine polishing stages is an asphalt polishing mold, and the polishing mold used in the repair polishing stage is a repair polishing mold with a polishing flannel cloth as the base.

[0023] Preferably, in the rough grinding stage of step 1, the lens edge thickness difference is controlled within 0.02 mm by manual grinding.

[0024] Exemplarily, the specific process of the off-disk polishing stage described in step 4 is: clamp the parts in sequence on the lens concave surface polishing clamping fixture and the lens convex surface polishing clamping fixture, polish the concave surface and convex surface of the lens respectively, press the surface to be polished on the surface of the polishing mold velvet cloth during polishing, add diamond solution, and operate the equipment for polishing.

[0025] Furthermore, the film material of the antireflection film in step 5 is zinc selenide, zinc sulfide and yttrium fluoride.

[0026] Furthermore, in step 5, the substrate baking temperature during the antireflection film deposition is 150° C., and the ion source energy is 110 eV.

[0027] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0028] 1. In view of the symmetry of thick lenses such as chalcogenide glass and the low hardness of the materials, the present invention adopts a processing technology of rough grinding → polishing → centering and edging → under-disk polishing → vacuum coating; in the rough grinding stage, the edge thickness difference is strictly controlled to lay a good foundation for subsequent precision processing and improve the centering accuracy; asphalt polishing molds and polishing velvet cloth-based polishing molds are respectively selected, and polishing agents of different particle sizes are adapted to polish the lenses after rough grinding in three stages, and the speed and load of the polishing machine are accurately controlled, taking into account the polishing efficiency and material hardness, so as to achieve surface defects within grade V; in the centering and edging stage, the center deviation is controlled within 0.01mm to ensure the centering accuracy; after the centering and edging, under-disk polishing is performed to remove surface scratches generated in the centering and edging process, so as to further improve the surface quality.

[0029] 2. The present invention adopts three stages of rough polishing, fine polishing and repair polishing to polish the roughly ground lens. In the first stage, W1 alumina polishing powder with larger particle size is used for rough polishing to quickly correct the surface shape of the part, and the surface defects are significantly improved compared with those after rough grinding; in the second stage, W0.3 alumina polishing powder with smaller particle size is selected for continuous polishing, and fine scratches on the surface of the part are effectively removed, and the surface defects are further improved; in the third stage, a repair polishing mold with a polishing flannel as the base is used, and W0.3 diamond solution with a particle size higher than that of alumina is selected as a polishing agent to avoid surface scratches while improving the polishing efficiency of the part.

[0030] 3. Aiming at the low hardness of chalcogenide glass, the present invention optimizes the main shaft, swing shaft speed and load process parameters of the polishing machine in the three-stage polishing process to ensure high glass surface quality and polishing efficiency.

[0031] 4. After the centering and edging is completed, the present invention can use a handheld repair and polishing clamping tool, which does not need to bond the lens to be processed to the polishing film, reduces the process of re-displacing, and simplifies the operation process; compared with traditional manual repair, the application of the repair and polishing clamping tool meets the requirements of uniform force for lenses of equal thickness, and the surface quality after repair and polishing is good, and the surface shape is not easy to change; after processing, the surface defects of the lens can be within Grade V, meeting the technical indicators.

[0032] 5. The present invention combines the characteristics of low deformation temperature of chalcogenide glass materials (only 170°C) and sets the key process parameters of vacuum coating to be substrate baking temperature (150°C) and ion source energy 110eV to ensure film adhesion.

[0033] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0035] FIG1( a ) is a lens concave surface repair and polishing clamping tool of the present invention;

[0036] FIG1( b ) is a lens convex surface polishing clamping tool of the present invention;

[0037] FIG2( a ) is a lens concave surface polishing mold according to the present invention;

[0038] FIG2( b ) is a lens convex surface polishing mold of the present invention;

[0039] Figure 3 This is a side view of the chalcogenide glass IRG204 lens according to Example 1 of the present invention.

[0040] Reference numerals:

[0041] 1-handheld end; 2-lens clamping point; 3-clamping edge; 4-clamping surface; 5-polishing velvet layer; 6-device interface; d-edge thickness. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0043] During the processing of equal-thickness lenses, since the edge and center thickness are the same, the stress distribution and wear of the edge part during grinding and polishing are likely to be different from those of the center part, thus affecting the uniformity of the surface quality; due to the symmetry of equal-thickness lenses, any asymmetry during the processing may lead to an increase in center deviation, requiring higher centering accuracy.

[0044] The processing of thick lenses such as chalcogenide glass requires strict control of process parameters such as uniformity and strength of grinding and polishing, as well as precise measurement and adjustment of deviation range in key links to ensure that the processed parts meet high precision and high quality requirements.

[0045] A specific embodiment of the present invention discloses a method for processing a chalcogenide glass equal thickness lens, comprising the following steps:

[0046] Step 1, rough grinding: manually grind both sides of the lens, and control the thickness difference of the lens edge to within 0.02mm;

[0047] Step 2, polishing: polishing the roughly ground lens in three stages, the polishing agents used in the three stages are: W1 aluminum oxide polishing powder, W0.3 aluminum oxide polishing powder, W0.3 diamond solution;

[0048] Step 3: Centering and edge grinding: Use the table method to correct the lens center deviation <0.01mm and complete the edge grinding of the parts;

[0049] Step 4: Polishing under the plate: Use the polishing die and clamping tooling to polish both sides of the part to remove scratches on the surface of the part;

[0050] Step 5: Vacuum coating: Anti-reflection film is coated on both sides of the lens.

[0051] Specifically, in step 1, during the rough grinding stage, the edge thickness difference of the lens is controlled within 0.02mm by manual grinding, ensuring that the center deviation of the lens is less than 0.01mm during the centering and edging stage; after grinding, the center thickness of the lens is greater than the finished thickness of the lens by 0.15-0.2mm, and the edge thickness difference is not greater than 0.02mm, and then the polishing process is entered.

[0052] In the rough grinding stage, on the basis of improving the part surface shape and surface quality, the focus is on controlling the part edge thickness difference, so that the center deviation of the part can be corrected in the centering and grinding stage.

[0053] Controlling the appropriate edge thickness difference lays a good foundation for subsequent precision machining. In the centering and edging stage, it is easier to achieve precise centering, improve the centering accuracy of parts, and reduce the risk of part deformation due to uneven material removal in subsequent processing.

[0054] In one possible design, a CM800 grinder is used, and diamond abrasive (grain size W14) is used as the auxiliary material. The handheld part is ground on one side in the mold for 10-15 minutes. The surface quality and shape of the part are effectively improved, reducing the difficulty of the polishing stage. During grinding, the edge thickness difference of the mirror body is monitored. When the edge thickness difference is greater than 0.02mm, the grinding direction and force are adjusted in time to correct the edge thickness difference to within 0.02mm, reducing the difficulty of subsequent centering and edge grinding.

[0055] Furthermore, the roughly ground lens is polished in three stages, including rough polishing, fine polishing and repair polishing.

[0056] Specifically, the rough polishing stage includes the following steps:

[0057] S101, cleaning the roughly ground lens, pasting it on the film to complete the plate, pressing it on the polishing mold coated with W1 alumina polishing powder with a stylus pen, adjusting the position so that the surface of the lens fits the surface of the polishing mold;

[0058] S102, turn on the polishing machine, rotate the polishing mold, and perform rough polishing.

[0059] Preferably, in the rough polishing stage step S102, the main shaft speed of the polishing machine is controlled at 40r / min to 50r / min, the swing shaft speed is controlled at 30r / min to 40r / min, and the load is 9 to 10N;

[0060] Exemplarily, in step S102, the polishing time is 4 to 5 hours, and the surface shape of the part is controlled within 5 apertures, without large spots (diameter 0.7 to 1 mm) and large scratches (length 15 to 20 mm, width 0.07 to 0.1 mm).

[0061] Furthermore, the fine polishing stage comprises the following steps:

[0062] S201, clean and wipe the lens after rough polishing, press it on the polishing mold with a stylus, and add W0.3 aluminum oxide polishing liquid;

[0063] S202, turn on the polishing machine, rotate the polishing mold, and perform fine polishing with the same equipment parameters as in the rough polishing stage.

[0064] Specifically, in step S202, the polishing time is 4 to 5 hours, the surface shape of the part is controlled within 5 apertures, the surface roughness is Ra0.012um, there are no large sand holes (diameter 0.7 to 1mm) and large scratches (length 15 to 20mm, width 0.07 to 0.1mm), and the number of scratches within a width of 0.07mm is no more than 10.

[0065] Furthermore, the polishing stage comprises the following steps:

[0066] S301, after replacing the polishing mold, place the finely polished and cleaned lens on the polishing mold, and use a diamond solution with a particle size of W0.3 as a polishing agent;

[0067] S302, turn on the polishing machine, rotate the polishing mold, and perform repair polishing with the same equipment parameters as in the rough polishing and fine polishing stages.

[0068] Preferably, in step S302, the polishing time is 15 to 20 minutes, the surface shape of the part is controlled within 5 apertures, the surface roughness is Ra0.012um, there are no large sand holes (diameter 0.7 to 1mm) and large scratches (length 15 to 20mm, width 0.07 to 0.1mm), and the surface defects are within level V.

[0069] It is worth noting that the polishing mold used in the rough polishing and fine polishing stages is an asphalt polishing mold, and the polishing mold used in the repair polishing stage is a repair polishing mold with a polishing flannel cloth as the base.

[0070] Asphalt polishing molds are used in the rough polishing and fine polishing stages, and the polishing efficiency is high. However, due to the low hardness of chalcogenide glass materials, although the asphalt polishing molds used in the rough polishing and fine polishing stages have a hardness of only 60 degrees, the hardness is still relatively high, and it is easier to cause scratches on the surface during actual polishing. During the repair and polishing stage, adjustments are made to the polishing base, and a repair and polishing mold with a polishing flannel cloth as the base is used. At the same time, a diamond solution with a particle size of W0.3 and a hardness higher than that of alumina is selected as a polishing agent to ensure the efficiency of the parts during polishing.

[0071] In the first stage, coarse polishing is performed with W1 alumina polishing powder with a larger particle size. The main purpose is to quickly correct the surface shape of the part. The surface of the part is polished to be very bright, and the surface defects have been significantly improved compared to coarse grinding. However, there are a large number of fine scratches on the surface, which need to be corrected with polishing powder with a finer particle size; in the second stage, fine polishing, the fine scratches on the surface of the part are effectively removed, and the surface defects are further improved, but there are still a small number of fine scratches on the surface, which is still a certain distance away from the surface defect level of the part application; after the third stage of repair polishing, the fine scratches on the surface of the part are basically removed, which can better meet the needs of the surface defects of the part, and due to the short polishing time, the surface shape of the part will not change significantly, and it can still meet the requirements of the drawing.

[0072] Furthermore, the specific operation of the centering and edge grinding described in step 3 is: place the polished parts above the edge grinding machine joint to facilitate the vacuum adsorption device of the equipment to be tightly sucked; adsorb the magnetic meter device on the inner side wall of the equipment, lightly press the magnetic meter probe on the surface of the mirror body, rotate the mirror body, and observe the vibration of the magnetic meter needle. If the vibration is greater than 0.01mm, tap the edge of the lens and move the lens position; continue to rotate the mirror body, observe the vibration of the magnetic meter needle until it is less than 0.01mm, adjust the program, and complete the edge grinding of the parts.

[0073] Since chalcogenide glass is opaque in the visible light band, it is impossible to perform high-precision centering and edge grinding on it using a transmission-type laser centering and edge grinding machine, and then to complete the correction of the center deviation of the lens; manual centering with a meter is used for centering, and the center deviation is controlled within 0.01mm, which is easy to operate.

[0074] Furthermore, the specific process of the off-disk polishing stage described in step 4 is: clamping the parts in sequence on the lens concave surface polishing clamping fixture and the lens convex surface polishing clamping fixture, and polishing the concave surface and convex surface of the lens respectively, pressing the surface to be polished on the surface of the polishing mold velvet cloth during polishing, adding diamond solution, and operating the equipment for polishing, wherein the spindle speed is controlled at 40r / min~50r / min, the swing shaft speed is controlled at 30r / min~40r / min, and the load is 9~10N.

[0075] Preferably, during the polishing under the plate, the single polishing time is 15 to 20 minutes, and the number of polishing times is 1 to 5 times, so as to effectively remove the scratches on the surface of the chalcogenide glass after centering and edge grinding.

[0076] The repair and polishing clamping tool includes a handheld end 1 and a lens clamping part 2; the lens clamping part 2 is a groove matching the size of the lens to be processed, including a clamping surface 4 and a clamping edge 3, the clamping surface 4 is in contact with the non-repaired surface of the lens, and the thickness of the clamping edge 3 is 1 mm less than the thickness d of the edge of the lens to be processed.

[0077] The thickness of the clamping edge 3 is 1 mm smaller than the thickness d of the edge of the lens to be processed, which facilitates the placement and removal of the lens; when the polishing clamping tool is used, after evenly applying sealing wax on the clamping surface 4, the lens to be processed is placed in the clamping position 2, and after the polishing is completed, the sealing wax is wiped off with alcohol.

[0078] Preferably, the material of the polishing and repairing clamping tool is polytetrafluoroethylene, which has moderate hardness and is well matched with chalcogenide glass.

[0079] The repair and polishing mold includes a main body, an equipment interface and a working surface; the equipment interface is connected to the polishing equipment, the working surface is fitted with the to-be-repaired and polished surface of the lens to be processed, and a layer of polishing velvet cloth is pasted on the surface; the repair and polishing mold main body is made of aluminum, the material hardness is moderate, and it matches well with chalcogenide glass.

[0080] It should be noted that when the center deviation of the part is controlled by the gauge during the edge grinding stage, the gauge probe may cause certain fine scratches on the lens surface. Therefore, after centering and edge grinding, it is necessary to use a polishing die to continue polishing the part to improve its surface quality.

[0081] Through the application of the repair and polishing clamping tool, there is no need to stick the lens to be processed on the polishing film again, which reduces the re-displacing process; compared with traditional manual repair, the application of the repair and polishing clamping tool can meet the requirements of uniform force for lenses of equal thickness, and the surface quality after repair and polishing is good and the surface shape is not easy to change; after processing, the surface defects of the lens can be within Grade V, meeting the technical indicators.

[0082] Furthermore, the film material of the antireflection film in step 5 is zinc selenide, zinc sulfide and yttrium fluoride, and the number and thickness of the film layers are determined according to actual needs.

[0083] Preferably, in step 5, the substrate baking temperature during the antireflection film deposition is 150° C., and the ion source energy is 110 eV;

[0084] Considering the low deformation temperature of chalcogenide glass material (only 170°C), and in order to ensure the adhesion of the film layer, the key process parameters are substrate baking temperature (150°C) and ion source energy of 110eV.

[0085] Specifically, during vacuum coating, a thermal evaporation coating equipment equipped with an ion source is selected. After the parts are wiped, they are placed on the equipment umbrella stand for coating. After the film is plated, the parts are tested to have a transmittance of more than 95% at 8-12um, and the film layer does not fall off after high and low temperature, humidity and heat, and salt spray environment tests.

[0086] In summary, the present invention adopts the processing technology of rough grinding → polishing → centering and edging → under-disk polishing → vacuum coating for processing in view of the symmetry of thick lenses such as chalcogenide glass and the characteristics of low material hardness; strictly controls the edge thickness difference in the rough grinding stage to lay a good foundation for subsequent precision processing and improve the centering accuracy; selects asphalt polishing molds and polishing velvet cloth as the base of the polishing mold, and adapts to polishing agents of different particle sizes, and polishes the rough-ground lens in three stages, accurately controls the speed and load of the polishing machine, takes into account the polishing efficiency and material hardness, and achieves surface defects within grade V; controls the center deviation within 0.01mm in the centering and edging stage to ensure the centering accuracy; performs under-disk polishing after centering and edging to remove surface scratches generated in the centering and edging process, and further improves the surface quality.

[0087] The method for processing thick lenses made of chalcogenide glass of the present invention is described below with reference to specific embodiments.

[0088] Example 1

[0089] This embodiment provides a method for processing a chalcogenide glass IRG204 lens.

[0090] Technical indicators: N=5, △N=1, B=Ⅳ, C=0.01; high-efficiency anti-reflection film is plated on both sides, the transmittance meets 8um~12um, and the average transmittance is ≥92%.

[0091] The specific processing methods are as follows:

[0092] Step 1, rough grinding: the application equipment is a domestic CM800 grinder, with auxiliary material corundum (grain size W14), to rough grind the lens; hold the part and grind the surface to be processed in the mold. During grinding, the edge thickness difference of the lens body should be monitored. When the index is greater than 0.02mm, adjust the grinding direction and force in time, and correct the edge thickness difference to within 0.02mm to reduce the difficulty of subsequent centering and edge grinding. After grinding, the center thickness of the test piece is greater than the finished thickness by 0.15-0.2mm, and the edge thickness difference is not greater than 0.02mm, then polishing can be carried out; the grinding time is 10-15min.

[0093] Step 2, polishing: polish the roughly ground lens in three stages, using a domestically produced MMP120 polishing machine;

[0094] Rough polishing:

[0095] S101, pasting the roughly ground lens onto the polishing film to complete the mounting, and then placing it on an asphalt polishing mold coated with W1 alumina polishing powder, and adjusting the position so that the surface of the lens fits the surface of the polishing mold;

[0096] S102. Turn on the polishing machine and rotate the asphalt polishing mold. The spindle speed is controlled at 40r / min-50r / min, the swing shaft speed is controlled at 30r / min-40r / min, the load is 9-10N, and rough polishing is performed. The polishing time is 4h. The surface shape of the part is controlled within 5 apertures. There are no hemp spots (diameter 0.7-1mm) and large scratches (length 15-20mm, width 0.07-0.1mm), and the surface of the part is cleaned.

[0097] Fine polishing:

[0098] S201, placing the roughly polished and cleaned lens on an asphalt polishing mold, and adding W0.3 aluminum oxide polishing liquid;

[0099] S202. Turn on the polishing machine and rotate the asphalt polishing mold. The equipment parameters are the same as those in the rough polishing stage. Perform fine polishing for 4 hours. Control the surface shape of the part within 5 apertures, the surface roughness Ra0.012um, and there are no large sand holes (diameter 0.7-1mm) and large scratches (length 15-20mm, width 0.07-0.1mm). The number of scratches within a width of 0.07mm is no more than 10, and the surface of the part is cleaned.

[0100] Repair and polish:

[0101] S301, replace the polishing mold, use a polishing mold with flannel as the base, place the finely polished and cleaned lens on the polishing mold, and use a diamond solution with a particle size of W0.3 as a polishing agent;

[0102] S302, turn on the polishing machine and rotate the polishing mold. The equipment parameters are the same as those in the rough polishing and fine polishing stages. Perform repair polishing for 15 to 20 minutes. Control the surface shape of the part within 5 apertures and clean the surface of the part.

[0103] After polishing, the technical indicators of the test piece were tested to be N=5, △N=1, B=Ⅳ, which met the requirements.

[0104] Step 3: Use a laser centering and edge grinding machine to center and edge grind the polished lens. Relying on the accuracy of the laser centering and edge grinding machine spindle, use the metering method to correct the center deviation of the lens and then complete the edge grinding of the part. The specific operation is: place the polished lens on the edge grinding machine joint to facilitate the vacuum adsorption device of the equipment to absorb tightly, adsorb the magnetic meter device on the inner side wall of the equipment, press the magnetic meter probe lightly on the surface of the mirror body, rotate the mirror body, and observe the magnetic meter needle jumping. If the jump is greater than 0.01mm, tap the edge of the lens and move the lens position; continue to rotate the mirror body and observe the magnetic meter needle jumping until it is less than 0.01mm; finally, adjust the program to complete the edge grinding of the part;

[0105] After edge grinding, the center deviation of the part was tested and found to be C=0.01, which met the requirements.

[0106] Step 4, under-disk polishing: Remove the parts from the polishing film to complete the under-disk, and use the under-disk polishing die to continue polishing the lens to remove new fine scratches on the surface and improve its surface quality; during polishing, use the designed clamping tooling to clamp the lens and polish the surface to be processed on the under-disk polishing die.

[0107] After polishing, the surface defects of the lens are within level V, meeting the technical indicators.

[0108] Step 5, vacuum coating: Use thermal evaporation coating equipment equipped with an ion source to coat the lens. After wiping the lens, place it on the equipment umbrella stand tooling to wait for coating. The film materials are zinc selenide, zinc sulfide and yttrium fluoride. When coating, combined with the characteristics of low deformation temperature of this type of material (only 170°C), and in order to ensure the goal of film adhesion, the key process parameters are substrate baking temperature (150 degrees Celsius) and ion source energy 110eV.

[0109] After the film is plated, the test piece has a transmittance of more than 95% at 8-12um. The film does not fall off after high and low temperature, humidity and salt spray environment tests, meeting the technical index requirements.

[0110] Comparative Example 1

[0111] This embodiment provides a method for processing a chalcogenide glass IRG204 lens.

[0112] The technical index requirements are the same as those in Example 1.

[0113] The specific processing method is basically the same as that in Example 1, except that only rough polishing and fine polishing are performed in step 2.

[0114] Step 4: After polishing, inspect the lens surface for level VI defects.

[0115] Comparative Example 2

[0116] This embodiment provides a method for processing a chalcogenide glass IRG204 lens.

[0117] The technical index requirements are the same as those in Example 1.

[0118] The specific processing method is basically the same as that of Example 1, except that the polishing mold is not replaced during the polishing stage in step 2, and asphalt polishing molds are used in all three stages.

[0119] After polishing, the lens surface defects are detected to be level VI.

[0120] Comparative Example 3

[0121] This embodiment provides a method for processing a chalcogenide glass IRG204 lens.

[0122] The technical index requirements are the same as those in Example 1.

[0123] The specific processing method is basically the same as that of Example 1, except that step 4 of polishing under the plate is not performed.

[0124] After edge grinding, the lens surface defects are detected to be level VI.

[0125] Comparative Example 4

[0126] This embodiment provides a method for processing a chalcogenide glass IRG204 lens.

[0127] The technical index requirements are the same as those in Example 1.

[0128] The specific processing method is basically the same as that of Example 1, except that in step 1, the edge thickness difference is not monitored intensively during the rough grinding stage, and polishing begins when the edge thickness difference is greater than 0.02 mm.

[0129] As a result, after repeated trimming in the centering stage of step 3, it was impossible to achieve a center deviation of ≤0.01.

[0130] Example 1 adopts the processing technology provided by the present invention, and the parameters of each step meet the requirements of the present invention. After under-plate polishing, the lens surface defects are within Grade V, meeting the technical indicators. After the film system is plated, the film layer does not fall off after high and low temperature, humidity and heat and salt spray environment tests, meeting the technical indicators. Compared with Example 1, the comparative example does not perform under-plate polishing in the polishing stage, and the final lens surface defects cannot meet the technical requirements. Compared with Example 1, the comparative example 2 does not replace the polishing mold in the polishing stage, and the final lens surface defects cannot meet the technical requirements. Compared with Example 1, the comparative example 3 does not perform under-plate polishing, and the lens surface defects are detected to be Grade VI after edge grinding, which does not meet the technical requirements. Compared with Example 1, the comparative example 4 does not focus on monitoring the edge thickness difference in the rough grinding stage, and the subsequent centering stage is repeatedly trimmed, and the center deviation ≤ 0.01 cannot be achieved.

[0131] In summary, the present invention adopts the processing technology of rough grinding → polishing → centering and edging → under-disk polishing → vacuum coating for processing in view of the symmetry of thick lenses such as chalcogenide glass and the characteristics of low material hardness; strictly controls the edge thickness difference in the rough grinding stage to lay a good foundation for subsequent precision processing and improve the centering accuracy; selects asphalt polishing molds and polishing velvet cloth as the base of the polishing mold, and adapts to polishing agents of different particle sizes, and polishes the rough-ground lens in three stages, accurately controls the speed and load of the polishing machine, takes into account the polishing efficiency and material hardness, and achieves surface defects within grade V; controls the center deviation within 0.01mm in the centering and edging stage to ensure the centering accuracy; performs under-disk polishing after centering and edging to remove surface scratches generated in the centering and edging process, and further improves the surface quality.

[0132] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for processing a chalcogenide glass thick lens, characterized in that: The steps include: Step 1, rough grinding: manually grind both sides of the lens, and control the thickness difference of the lens edge to within 0.02mm; Step 2, polishing: polishing the roughly ground lens in three stages, the polishing agents used in the three stages are: W1 aluminum oxide polishing powder, W0.3 aluminum oxide polishing powder, W0.3 diamond solution; Step 3: Centering and edge grinding: Use the table method to correct the lens center deviation <0.01mm and complete the edge grinding of the parts; Step 4: Polishing: Use the polishing die and clamping fixture to polish both sides of the parts to remove scratches on the surface of the parts; Step 5: Vacuum coating: Anti-reflection film is coated on both sides of the lens.

2. The processing method according to claim 1, characterized in that: The rough-ground lens is polished in three stages as described in step 2, including rough polishing, fine polishing and repair polishing; The rough polishing stage comprises the following steps: S101, cleaning the roughly ground lens, pasting it on a polishing film to complete the mounting, and then placing it on a polishing mold coated with W1 alumina polishing powder, adjusting the position so that the surface of the lens fits the surface of the polishing mold; S102, turn on the polishing machine, rotate the polishing mold, and perform rough polishing. The polishing time is 4 to 5 hours. Control the surface shape of the part within 5 apertures and clean the lens.

3. The processing method according to claim 2, characterized in that: The fine polishing stage comprises the following steps: S201, placing the roughly polished and cleaned lens on a polishing mold, and adding W0.3 aluminum oxide polishing liquid; S202, turn on the polishing machine, rotate the polishing mold, and perform fine polishing. The polishing time is 4 to 5 hours. The surface shape of the part is controlled to be within 5 apertures, the surface roughness is Ra0.012um, and the number of scratches within a width of 0.07mm is not more than 10. Clean the lens.

4. The processing method according to claim 2, characterized in that: The polishing stage comprises the following steps: S301, after replacing the polishing mold, place the finely polished and cleaned lens on the polishing mold, and use a diamond solution with a particle size of W0.3 as a polishing agent; S302, turn on the polishing machine, rotate the polishing mold, and perform repair polishing. The repair polishing time is 15 to 20 minutes. The surface shape of the part is controlled within 5 apertures, the surface roughness is Ra0.012um, and the surface defects are within Grade V.

5. The processing method according to claim 2, characterized in that: During the three stages of rough polishing, fine polishing and repair polishing, the main shaft speed of the polishing machine is controlled at 40r / min-50r / min, the swing shaft speed is controlled at 30r / min-40r / min, and the load is 9-10N.

6. The processing method according to claim 5, characterized in that: The polishing mold used in the rough polishing and fine polishing stages is an asphalt polishing mold, and the polishing mold used in the repair polishing stage is a repair polishing mold with a polishing flannel cloth as the base.

7. The processing method according to claim 1, characterized in that: In the rough grinding stage of step 1, the lens edge thickness difference is controlled within 0.02mm by manual grinding.

8. The processing method according to claim 1, characterized in that: The specific process of the off-plate polishing stage described in step 4 is: clamp the parts on the lens concave surface polishing clamping fixture and the lens convex surface polishing clamping fixture in sequence, polish the concave surface and convex surface of the lens respectively, press the surface to be polished on the surface of the polishing mold velvet cloth during polishing, add diamond solution, and operate the equipment for polishing.

9. The processing method according to claim 1, characterized in that: The film material of the antireflection film in step 5 is zinc selenide, zinc sulfide and yttrium fluoride.

10. The processing method according to claim 9, characterized in that: In step 5, the substrate baking temperature during the antireflection film deposition is 150° C., and the ion source energy is 110 eV.

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