Method for treating surface defects of zinc selenide lenses

Abstract

The present disclosure provides a method for treating surface defects of zinc selenide lenses, comprising the steps of: placing the polished zinc selenide lens in an ultrasonic cleaning basket in a pure water tank with a resistivity of ≥15 MΩ·cm, and the pure water level submerging the top of the lens; immediately placing the zinc selenide lens immersed in pure water into a citric acid cleaning solution, and wiping the surface of the lens with cotton; placing the wiped zinc selenide lens into AK191 cleaning agent, and wiping the surface of the lens with cotton; placing the wiped zinc selenide lens into an ultrasonic cleaning basket immersed in pure water with a resistivity of ≥15 MΩ·cm, and then placing the ultrasonic cleaning basket into a strong alkali stock solution for immersion; placing the ultrasonic cleaning basket with the zinc selenide lens immersed into flowing pure water with a resistivity of ≥15 MΩ·cm for rinsing; and cleaning and drying the ultrasonic cleaning basket with the zinc selenide lens according to the ultrasonic cleaning process after rinsing with pure water. The above method can solve the problems of scratches during wiping before coating and white marks after coating of the zinc selenide lens.

Description

Technical Field

[0001] This disclosure relates to the field of optics, specifically to infrared lenses, and more specifically to a method for treating surface defects in zinc selenide lenses. Background Technology

[0002] Zinc selenide lenses are mainly used as the mainstream product for infrared laser lenses. After fine processing and polishing, and before coating, this material is treated by two methods: manual wiping and ultrasonic cleaning. However, both methods result in different surface abnormalities.

[0003] The manual wiping method involves wiping the polished lens surface once with cotton soaked in pure water and hand soap, then wiping the surface 2-3 times with a lint-free cloth soaked in alcohol, wiping the surface twice with a lint-free cloth soaked in alcohol before coating, then wiping the surface twice with a lint-free cloth soaked in diamond powder and alcohol, then wiping the surface 3-5 times with a lint-free cloth soaked in alcohol, and finally wiping the surface 3-5 times with cotton soaked in acetone. However, the manual wiping method has defects: (1) the surface wiping is uneven, and about 50% of the white marks are abnormal after coating; (2) the purpose of wiping with a lint-free cloth soaked in diamond powder and alcohol before coating is to remove the oxides after the polishing powder on the lens surface has dried, but the effect is not good and it is easy to cause scratches on the surface, with an average scratch rate of about 20%.

[0004] After polishing and before coating, ultrasonic cleaning is used. After coating, the percentage of abnormal white marks on the surface is generally between 15% and 20%.

[0005] While both ultrasonic cleaning methods described above yield relatively good results, white marks appear on the lens surface after coating. This is because polishing powder residue remains on the lens surface after polishing, and this residue dries and forms oxides that adhere firmly to the lens surface. Therefore, neither of these methods effectively solves the problem of surface defects in zinc selenide. Summary of the Invention

[0006] To address the issues of scratches during wiping before zinc selenide lens coating and white marks appearing after coating, this disclosure provides a method for treating surface defects on zinc selenide lenses, including the following steps:

[0007] S1: Place the polished zinc selenide lens on an ultrasonic cleaning basket in a pure water tank with a resistivity ≥15MΩ.cm. The pure water level should submerge the top of the lens. S2: Remove the zinc selenide lens from the pure water and immediately place it in a citric acid cleaning solution. Wipe the lens surface with cotton. S3: Place the wiped zinc selenide lens in AK191 cleaning agent and wipe the lens surface with cotton. S4: Place the wiped zinc selenide lens in the ultrasonic cleaning basket and immerse it in pure water with a resistivity ≥15MΩ.cm. Then, immerse the ultrasonic cleaning basket in a strong alkaline solution. S5: Rinse the ultrasonic cleaning basket containing the zinc selenide lens in flowing pure water with a resistivity ≥15MΩ.cm. S6: After rinsing with pure water, clean and dry the ultrasonic cleaning basket containing the zinc selenide lens according to the ultrasonic cleaning process. The treatment is complete.

[0008] In some embodiments, in step S2, the ratio of water to citric acid in the citric acid cleaning solution is (10-15):1.

[0009] In some embodiments, in step S2, cotton is used to wipe the lens surface once in both the front and back directions.

[0010] In some embodiments, in step S3, the ratio of water to cleaning agent in the AK191 diluted cleaning agent is 100:(5-8).

[0011] In some embodiments, in step S3, cotton is used to wipe the lens surface once in both the front and back directions.

[0012] In some embodiments, in step S4, the immersion temperature in the strong alkali stock solution is 48°C to 50°C.

[0013] In some embodiments, in step S4, the soaking time in the strong alkali stock solution is 1 min to 3 min.

[0014] In some embodiments, in step S5, the rinsing time in pure water is 2 min to 3 min.

[0015] In some embodiments, clean gloves must be worn during the wiping process.

[0016] The beneficial effects of this disclosure are as follows: The processing method described in this disclosure replaces the wiping action of polishing liquid before coating, which can avoid scratching the lens; after polishing, wiping the zinc selenide lens with citric acid + AK191 diluted solution can remove residual white stains and oxide layer on the lens surface, avoid the problem of dirt and whitening after lens coating, greatly reduce the probability of lens coating scrap and rework, and improve the pass rate. Detailed Implementation

[0017] It should be understood that the disclosed embodiments are merely examples of this disclosure, which can be implemented in various forms. Therefore, the specific details of this disclosure should not be construed as limiting, but are intended only as the basis for the claims and as an illustrative basis for teaching those skilled in the art how to implement this disclosure in various ways.

[0018] In this disclosure, any terms and technical jargon not explicitly stated are common knowledge to those skilled in the art, and any methods not explicitly stated are conventional methods known to those skilled in the art. The ultrasonic cleaning process and drying method described in this disclosure are known in the art and can be optimized and adjusted non-inventively according to actual needs.

[0019] The technical solution provided in this disclosure aims to solve the problems of white marks after coating of zinc selenide lenses and scratches from wiping before coating. The method for treating surface defects of zinc selenide lenses provided in this disclosure includes surface treatment method 1 and / or surface treatment method 2. When the polished zinc selenide lens completes surface treatment method 1, it can be directly coated without inspection; when the polished zinc selenide lens completes surface treatment method 1, if the lens needs to be inspected, surface treatment method 2 is still required before coating.

[0020] [Surface Treatment Method 1]

[0021] The method for treating surface defects of zinc selenide lenses disclosed herein includes the following steps:

[0022] S1: Place the polished zinc selenide lens on an ultrasonic cleaning basket in a pure water tank with a resistivity ≥15MΩ.cm. The pure water level should submerge the top of the lens. S2: Remove the zinc selenide lens from the pure water and immediately place it in a citric acid cleaning solution. Wipe the lens surface with cotton. S3: Place the wiped zinc selenide lens in AK191 cleaning agent and wipe the lens surface with cotton. S4: Place the wiped zinc selenide lens in the ultrasonic cleaning basket and immerse it in pure water with a resistivity ≥15MΩ.cm. Then, immerse the ultrasonic cleaning basket in a strong alkaline solution. S5: Rinse the ultrasonic cleaning basket containing the zinc selenide lens in flowing pure water with a resistivity ≥15MΩ.cm. S6: After rinsing with pure water, clean and dry the ultrasonic cleaning basket containing the zinc selenide lens according to the ultrasonic cleaning process. The treatment is complete.

[0023] In step S1, placing the lens in pure water ensures that the lens is not re-contaminated and is not dried out, which is beneficial for subsequent cleaning.

[0024] In step S2, citric acid effectively removes the polishing solution from the lens surface. In some embodiments, in step S2, the ratio of water to citric acid in the citric acid cleaning solution is (10-15):1. In some embodiments, in step S2, cotton is used to wipe the lens surface once in both directions. In some embodiments, clean gloves must be worn during the wiping process in step S2.

[0025] In step S3, the cleaning agent wipes away the citric acid on the lens surface to prevent residual citric acid from causing white spots on the lens surface. In some embodiments, in step S3, the ratio of water to cleaning agent in the AK191 diluted cleaning agent is 100:(5-8). In some embodiments, in step S3, the lens surface is wiped once on each side using cotton. In some embodiments, clean gloves must be worn during the wiping process in step S3.

[0026] In step S4, immersing the lens in pure water prevents it from drying out. In step S4, by adjusting the soaking temperature and time, the dirt and grime remaining on the lens and cleaning basket can be completely dissolved. In some embodiments, in step S4, the soaking temperature in the strong alkaline solution is 48°C to 50°C. In some embodiments, in step S4, the soaking time in the strong alkaline solution is 1 min to 3 min. In some embodiments, in step S4, the strong alkaline solution includes at least one of WIN-18 and AK181 cleaning agents.

[0027] In step S5, rinsing the lens in pure water removes the strong alkali from the lens surface. In some embodiments, the rinsing time in pure water in step S5 is 2 to 3 minutes.

[0028] In the above steps, immersing the polished lens in pure water with a resistivity ≥15MΩ.cm can prevent the lens from drying out and oxidizing.

[0029] [Surface Treatment Method 2]

[0030] After completing steps S1 to S6 of the treatment of surface defects of zinc selenide lenses, if the lenses are to be inspected, the ultrasonic cleaning basket containing the polished zinc selenide lenses after drying in step S6 should be placed in a dustproof box, covered, and then sent for inspection to prevent the cleaned lenses from being contaminated again.

[0031] After lens inspection is completed and before the zinc selenide lens is coated, the lens still needs to be cleaned because the inspection process can re-contaminate it. This includes the following steps:

[0032] B1: Immerse the cleaning basket containing the zinc selenide lens after testing in a strong alkaline solution; B2: After immersion, rinse the ultrasonic cleaning basket containing the zinc selenide lens before coating in flowing pure water with a resistivity ≥15MΩ.cm; B3: After rinsing with pure water, clean and dry the ultrasonic cleaning basket containing the zinc selenide lens before coating according to the ultrasonic cleaning process.

[0033] In step B1, by adjusting the soaking temperature and time, adhering substances and dirt generated on the lenses during inspection and handling can be dissolved. In some embodiments, in step B1, the soaking temperature in the strong alkaline solution is 48°C to 50°C. In some embodiments, in step B1, the soaking time in the strong alkaline solution is 1 min to 3 min. In some embodiments, in step B1, the strong alkaline solution includes at least one of WIN-18 and AK181 cleaning agents.

[0034] In step B2, rinsing the lens in pure water removes the strong alkali from the lens surface. In some embodiments, the rinsing time in pure water in step B2 is 2 to 3 minutes.

[0035] The present disclosure is further illustrated below with reference to the embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the disclosure. Unless otherwise specified, the reagents, materials, and instruments used in the following embodiments and comparative examples are commercially available or prepared by methods known in the art. The zinc selenide lenses used in the following examples are all polished zinc selenide lenses, and the number of lenses used in each example is the same.

[0036] Example 1

[0037] Place each polished zinc selenide lens individually on an ultrasonic cleaning basket in a pure water tank with a resistivity ≥15 MΩ·cm, ensuring the water level completely submerges the top of the lens. Immediately remove the zinc selenide lens from the pure water and immerse it in a citric acid cleaning solution (water to citric acid ratio 10:1). Wipe the lens surface on both sides with cotton wool, wearing cleanroom gloves throughout the process. Next, place the polished zinc selenide lens, now cleaned with citric acid, into a 100:5 diluted AK191 cleaning agent solution and wipe the lens surface on both sides with cotton wool, again wearing cleanroom gloves. Finally, immerse the cleaned zinc selenide lens in the ultrasonic cleaning basket, submerging it in pure water with a resistivity ≥15 MΩ·cm. Then, place the ultrasonic cleaning basket into a strong alkaline solution heated to 48℃~50℃ for 3 minutes. After soaking in strong alkali, the ultrasonic cleaning basket containing the polished zinc selenide lens is placed in flowing pure water with a resistivity ≥15MΩ.cm and rinsed for 2 to 3 minutes. After rinsing with pure water in the previous step, the ultrasonic cleaning basket containing the zinc selenide lens is cleaned and dried according to the ultrasonic cleaning process to complete the treatment.

[0038] After drying, the ultrasonic cleaning basket containing the polished zinc selenide lens is placed in a dustproof box, covered, and sent for testing.

[0039] After polishing and testing, the zinc selenide lenses are placed in a dustproof box, covered, and then sent for coating. Before coating, the following process is performed: the cleaning basket containing the zinc selenide lenses after testing is immersed in a strong alkaline solution heated to 48℃~50℃ for 3 minutes; after immersion in the strong alkaline solution, the ultrasonic cleaning basket containing the zinc selenide lenses before coating is rinsed in flowing pure water with a resistivity ≥15MΩ.cm for 2 to 3 minutes; after rinsing with pure water, the ultrasonic cleaning basket containing the zinc selenide lenses before coating is cleaned and dried according to the ultrasonic cleaning process.

[0040] Comparative Example 1

[0041] Place the polished zinc selenide lens individually on an ultrasonic cleaning basket in a pure water tank with a resistivity ≥15 MΩ·cm, ensuring the water level completely submerges the top of the lens. Then, place the zinc selenide lens, now immersed in pure water, into a 100:5 diluted AK191 cleaning solution. Wipe the lens surface on both sides with cotton wool, wearing clean gloves throughout the process. Next, immerse the cleaned zinc selenide lens in the ultrasonic cleaning basket, submerging it in pure water with a resistivity ≥15 MΩ·cm. Finally, place the ultrasonic cleaning basket into a strong alkaline solution heated to 48℃~50℃ for 3 minutes.

[0042] After soaking in strong alkali, the ultrasonic cleaning basket containing the polished zinc selenide lens is placed in flowing pure water with a resistivity ≥15MΩ·cm and rinsed for 2-3 minutes. Following the rinsing with pure water in the previous step, the ultrasonic cleaning basket containing the zinc selenide lens is then cleaned and dried according to the ultrasonic cleaning process to complete the treatment.

[0043] After drying, the ultrasonic cleaning basket containing the polished zinc selenide lens is placed in a dustproof box, covered, and sent for testing.

[0044] After polishing and testing, the zinc selenide lenses are placed in a dustproof box, covered, and then sent for coating. Before coating, the following process is performed: the cleaning basket containing the zinc selenide lenses after testing is immersed in a strong alkaline solution heated to 48℃~50℃ for 3 minutes; after immersion in the strong alkaline solution, the ultrasonic cleaning basket containing the zinc selenide lenses before coating is rinsed in flowing pure water with a resistivity ≥15MΩ.cm for 2 to 3 minutes; after rinsing with pure water, the ultrasonic cleaning basket containing the zinc selenide lenses before coating is cleaned and dried according to the ultrasonic cleaning process.

[0045] Comparative Example 2

[0046] Place each polished zinc selenide lens individually on an ultrasonic cleaning basket containing pure water with a resistivity ≥15 MΩ·cm, ensuring the water level completely submerges the top of the lens. Immediately remove the zinc selenide lens from the pure water and immerse it in a citric acid cleaning solution (water to citric acid ratio 10:1). Wipe the lens surface on both sides with cotton wool, wearing clean gloves throughout the process. After wiping, place the zinc selenide lens in the ultrasonic cleaning basket and immerse it in pure water with a resistivity ≥15 MΩ·cm. Then, immerse the ultrasonic cleaning basket in a strong alkaline solution heated to 48℃~50℃ for 3 minutes. After immersion in the strong alkaline solution, rinse the ultrasonic cleaning basket containing the polished zinc selenide lens in flowing pure water with a resistivity ≥15 MΩ·cm for 2~3 minutes. Finally, clean and dry the ultrasonic cleaning basket containing the zinc selenide lens according to the ultrasonic cleaning process to complete the treatment.

[0047] After drying, the ultrasonic cleaning basket containing the polished zinc selenide lens is placed in a dustproof box, covered, and sent for testing.

[0048] After polishing and testing, the zinc selenide lenses are placed in a dustproof box, covered, and then sent for coating. Before coating, the following process is performed: the cleaning basket containing the zinc selenide lenses after testing is immersed in a strong alkaline solution heated to 48℃~50℃ for 3 minutes; after immersion in the strong alkaline solution, the ultrasonic cleaning basket containing the zinc selenide lenses before coating is rinsed in flowing pure water with a resistivity ≥15MΩ.cm for 2 to 3 minutes; after rinsing with pure water, the ultrasonic cleaning basket containing the zinc selenide lenses before coating is cleaned and dried according to the ultrasonic cleaning process.

[0049] Comparative Example 3

[0050] Place each polished zinc selenide lens individually on an ultrasonic cleaning basket in a pure water tank with a resistivity ≥15 MΩ·cm, ensuring the water level completely submerges the top of the lens. Immediately remove the zinc selenide lens from the pure water and immerse it in a citric acid cleaning solution (water to citric acid ratio 10:1). Wipe the lens surface on both sides with cotton wool, wearing cleanroom gloves throughout the process. Place the polished zinc selenide lens, now cleaned with citric acid, into a 100:5 diluted AK191 cleaning solution and wipe the lens surface on both sides with cotton wool, again wearing cleanroom gloves. Rinse the ultrasonic cleaning basket containing the polished zinc selenide lens in flowing pure water with a resistivity ≥15 MΩ·cm for 2-3 minutes. After rinsing with pure water, clean and dry the ultrasonic cleaning basket containing the zinc selenide lens according to the ultrasonic cleaning process to complete the treatment.

[0051] After drying, the ultrasonic cleaning basket containing the polished zinc selenide lens is placed in a dustproof box, covered, and sent for testing.

[0052] After polishing and testing, the zinc selenide lens is placed in a dustproof box, covered, and sent for coating. Before coating, the following process is performed: the ultrasonic cleaning basket containing the zinc selenide lens before coating is cleaned and dried according to the ultrasonic cleaning process.

[0053] The lenses obtained after being cleaned using the methods described in the above embodiments and comparative examples were tested, and the percentage of scratches before coating, the percentage of white marks after coating, and the pass rate were statistically analyzed. The testing and statistical methods were all conventional methods known in the art. Specifically, the percentage of scratches = number of scratches / total number of tests, the percentage of white marks = number of white marks / total number of tests, and the pass rate = (number of white marks + number of scratches) / total number of tests. The results are shown in Table 1.

[0054] Table 1. Statistical results of lens tests in Example 1 and Comparative Examples 1-3

[0055] Percentage of scratches / % Percentage of white marks / % Pass rate / % Example 1 0 0 100 Comparative Example 1 0 20 80 Comparative Example 2 0 15 85 Comparative Example 3 0 15 85

[0056] The above description is merely an example of this disclosure and is not intended to limit this disclosure in any way. Although this disclosure is presented above with preferred embodiments, it is not intended to limit this disclosure. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solutions disclosed herein are equivalent to equivalent implementation cases and are all within the scope of the technical solutions disclosed herein.

Claims

1. A method for treating surface defects on zinc selenide lenses, characterized in that, Including the following steps: S1: Place the polished zinc selenide lens on the ultrasonic cleaning basket in a pure water tank with a resistivity ≥15 MΩ.cm. The pure water level should submerge the top of the lens. S2: Take out the zinc selenide lenses that are soaking in pure water and immediately put them into the citric acid cleaning solution. Wipe the surface of the lenses with cotton. The ratio of water to citric acid in the citric acid cleaning solution is (10~15):

1. S3: Place the zinc selenide lens that has been wiped in the previous step into AK191 cleaning solution and wipe the lens surface with cotton. The ratio of water to cleaning solution in AK191 diluted cleaning solution is 100:(5~8). S4: After wiping the zinc selenide lens in the previous step, place it in an ultrasonic cleaning basket and immerse it in pure water with a resistivity ≥15 MΩ.cm. Then, immerse the ultrasonic cleaning basket in a strong alkaline solution at a temperature of 48℃~50℃ for 1min~3min. S5: After soaking in the previous step, place the ultrasonic cleaning basket containing the zinc selenide lens into flowing pure water with a resistivity ≥15 MΩ.cm and rinse for 2 min to 3 min. S6: After rinsing with pure water in the previous step, the ultrasonic cleaning basket containing the zinc selenide lens is cleaned and dried according to the ultrasonic cleaning process to complete the treatment. After drying in step S6, the ultrasonic cleaning basket containing the polished zinc selenide lens is placed in a dustproof box, covered, and then sent for testing. After the lens inspection is completed and before the zinc selenide lens is coated, the zinc selenide lens undergoes a cleaning process, including the following steps: B1: After testing, place the cleaning basket containing the zinc selenide lens into the strong alkaline stock solution for immersion at a temperature of 48℃~50℃ for 1min~3min. B2: After soaking, place the ultrasonic cleaning basket containing the zinc selenide lens before coating into flowing pure water with a resistivity ≥15 MΩ.cm and rinse for 2 min to 3 min. B3: After rinsing with pure water, the ultrasonic cleaning basket containing the pre-coated zinc selenide lens is cleaned and dried according to the ultrasonic cleaning process.

2. The method for treating surface defects of zinc selenide lenses according to claim 1, characterized in that, In step S2, use cotton to wipe the lens surface once in both the front and back directions.

3. The method for treating surface defects of zinc selenide lenses according to claim 1, characterized in that, In step S3, use cotton to wipe the lens surface once on both the front and back.

4. The method for treating surface defects of zinc selenide lenses according to claim 1, characterized in that, Dust-free gloves must be worn during the wiping process.