High-quality processing technology for surface of BBO crystal device

Abstract

The invention discloses a high-quality machining process for the surface of a BBO crystal device. The high-quality machining process comprises the working procedures of orientation, cutting, disc loading, grinding, polishing and the like. The method comprises the following steps: firstly, obtaining a crystal meeting the order size requirement by using an orienting and cutting mode, then enclosing the BBO crystal and a padding into a small disc by using a hot melt adhesive, adhering the small disc to a glass substrate with the diameter of 100mm in a central symmetry manner by using 406 glue, and then grinding and polishing one light transmission surface of the crystal to finish the processing of the first surface; after the glass substrate is unloaded, polishing optical cement with the polished surface is arranged on the glass substrate in a central symmetry manner, the other surface is subjected to the same dull polish and polishing process, the glass substrate is heated and unloaded, then the glass substrate is soaked in gasoline to remove the hot melt adhesive, and wiping is carried out. The surface smoothness of the BBO crystal product reaches 10 / 5 specified by the American military standard MIL-PRF-13830B, the flatness of the BBO crystal product reaches lambda / 8, and lambda is equal to 632nm + / -2nm.

Description

Technical Field

[0001] The invention relates to the technical field of optical crystal processing, and in particular to a high-quality processing technology for the surface of a BBO crystal device. Background Art

[0002] β-BaB2O4 crystal (BBO crystal for short) has a wide phase matching band and a transparent band range, and has high frequency conversion efficiency and damage threshold. It is widely used in the double, triple, quadruple and quintuple frequency of Nd:YAG laser. Its Mohs hardness is 4, which is relatively low. It is easy to deliquesce, and it is easy to produce wires and cracks during processing. The traditional polishing process requires high skills of personnel, and the processing efficiency and yield are low, which cannot be achieved in mass production. Therefore, it is urgent to develop a high-quality processing technology for the surface of BBO crystal devices to improve processing efficiency and yield and achieve mass production. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a high-quality processing technology for the surface of a BBO crystal device and to provide a solution for the mass production of BBO crystals.

[0004] The technical solution adopted by the present invention is as follows: A high-quality surface processing technology for BBO crystal devices, which includes the following processes: orientation, cutting, mounting, grinding, polishing, etc.

[0005] S1. Orientation and cutting. After orientation and cutting, the thickness of the crystal substrate is H∈[0.2mm, 15mm] and the cross section is L×W, where L, W∈[8mm, 14mm].

[0006] S2. Place BBO on a glass slide and heat it to 90℃ to 100℃, then apply hot melt adhesive, and use the defective BBO crystal inside as padding, and surround the crystal to be ground with a square small plate with a cross-sectional size of D×D (called the upper small plate), D∈[14mm, 20mm], such as Figure 1 After compaction, wipe off the overflowed hot melt adhesive, cool to room temperature and remove the glass slide, and then use cold glue to adhere multiple square small plates to a glass substrate with a diameter of 100 mm (called the upper large plate) in a centrally symmetrical manner, as shown in the figure. Figure 2 shown.

[0007] S3. Grinding. Ring grinding is used for coarse grinding and fine grinding. 1000# and 2000# SiC sand are used as grinding media respectively. Water is used as coolant. The grinding turntable is made of white corundum. The rotation speed is 20-30rpm. The pressure load is 1-1.5kg. The thickness is removed by 0.2mm to 0.35mm.

[0008] S4. Polishing. A single-axis machine was used for rough polishing and fine polishing, with W0.25 diamond powder and W0.125 diamond powder as the grinding and polishing media, respectively. Water was used as the solvent with a mass concentration of 45%-55%. The polishing turntables used for rough polishing and fine polishing were made of polyurethane and asphalt, respectively. The rotation speed was 20-30rpm, the pressure load was 1-1.5kg, the size was reduced by 30-40μm, and the flatness of the polished surface reached λ / 8, where λ was 632nm±1nm.

[0009] S5. Lower plate and polishing. After the single-side polishing is completed, the lower plate is polished and the polished surface is polished. Multiple square small plates are symmetrically polished on a glass substrate with a diameter of 100 mm.

[0010] S6. Second side grinding. Repeat the same rough grinding and fine grinding process on the grinding surface to remove 0.2mm to 0.35mm of thickness.

[0011] S7. Second surface polishing. Repeat the rough polishing and fine polishing process on the surface to be polished, so that the crystal thickness reaches the required size, the polishing finish reaches 10 / 5, and the polishing surface flatness reaches λ / 8, where λ is 632nm±1nm.

[0012] S8. Remove the plate and clean. After completion, remove the glossy adhesive surface by heating at 90°C to 110°C, preferably 90°C. After cooling the plate, soak the small plate crystal in gasoline at 23°C to 25°C to remove the hot melt adhesive remaining on the crystal surface, and then wipe the polished surface of the crystal with a dust-free cloth.

[0013] The smoothness requirement is in accordance with the US military standard MIL-PRF-13830B.

[0014] The beneficial effects of the present invention are: (1) Compared with the traditional single-disk manual processing technology, the batch processing technology provided by this patent is less dependent on personnel experience, the various process parameters are controllable, and batch production can be carried out; (2) Compared with the traditional single-disk manual processing technology, the batch processing technology provided by this patent has better consistency in indicators such as size, surface shape, parallelism, etc. of the same batch of products. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of a square small plate of the present invention; Figure 2 It is a schematic diagram of an upper plate of the present invention. DETAILED DESCRIPTION

[0016] (1) Processing 10mm×10mm×3mm BBO crystal: S1. Orientation and cutting. After orientation and cutting, the thickness of the crystal substrate of β-BaB2O4 blank is 3.6mm±0.1mm, and the cross section is L×W, where L and W=10mm±0.1mm.

[0017] S2. Place BBO on a glass slide and heat it to 90℃ to 100℃, then apply hot melt adhesive. Use the defective BBO crystal inside as padding to enclose the crystal to be ground into a small square disk with a cross-sectional size of D×D (called the upper small disk), D=16mm. After compaction, wipe off the overflowed hot melt adhesive. After cooling to room temperature and removing the glass slide, use cold glue to adhere multiple square small disks symmetrically to a glass substrate with a diameter of 100mm (called the upper large disk).

[0018] S3. Grinding. Ring grinding is used for coarse grinding and fine grinding. 1000# and 2000# SiC sand are used as grinding media respectively. Water is used as coolant. The grinding turntable is made of white corundum. The rotation speed is 20-30rpm. The pressure load is 1-1.5kg. The thickness is removed by 0.2mm to 0.35mm.

[0019] S4. Polishing. A single-axis machine was used for rough polishing and fine polishing, with W0.25 diamond powder and W0.125 diamond powder as the grinding and polishing media, respectively. Water was used as the solvent with a mass concentration of 45%-55%. The polishing turntables used for rough polishing and fine polishing were made of polyurethane and asphalt, respectively. The rotation speed was 20-30rpm, the pressure load was 1-1.5kg, the size was reduced by 30-40μm, and the flatness of the polished surface reached λ / 8, where λ was 632nm±1nm.

[0020] S5. Lower plate and polishing. After the single-side polishing is completed, the lower plate is polished and the polished surface is polished. Multiple square small plates are symmetrically polished on the glass substrate with a diameter of 100 mm. S6. Second side grinding. Repeat the same rough grinding and fine grinding process on the grinding surface to remove 0.2mm to 0.35mm of thickness.

[0021] S7. Second surface polishing. Repeat the rough polishing and fine polishing process on the surface to be polished, so that the crystal thickness reaches 3mm±0.05mm, the polishing finish reaches 10 / 5, and the polishing surface flatness reaches λ / 8, where λ is 632nm±1nm.

[0022] S8. Remove the plate and clean. After completion, heat the plate to remove the glossy adhesive surface. The heating temperature is 90℃ to 110℃. After cooling the plate, soak the small plate crystal in gasoline at 23℃ to 27℃ to remove the hot melt adhesive remaining on the crystal surface. Then use a dust-free cloth to wipe the polished surface of the crystal.

Claims

1. A high-quality processing technology for the surface of a BBO crystal device, characterized by: The process includes the steps of crystal angle orientation, cutting, disk mounting, grinding and polishing. The β-BaB2O4 blank is oriented and cut, and the crystal substrate thickness is H and the cross-section is L×W, wherein H∈[0.2mm, 15mm], W∈[8mm, 14mm]; the disk mounting step is to place BBO on a glass slide, heat it to 90°C to 100°C, and then coat it with hot melt adhesive, and then use the defective BBO crystal inside as a pad, surround the crystal to be ground with a square small disk with a cross-sectional size of D×D, D∈[14mm, 20mm], and wipe off the overflowed hot melt adhesive after compaction. After cooling to room temperature and removing the glass slide, multiple square small disks are symmetrically mounted on a glass substrate with a diameter of 100mm using cold glue, and the cold glue used is 406 glue.

2. The high-quality surface processing technology of BBO crystal device according to claim 1 is characterized in that: The grinding is performed by ring grinding for coarse grinding and fine grinding, using 1000# and 2000# SiC sand as the grinding medium respectively, water as the coolant, the grinding turntable is made of white corundum, the rotation speed is 20-30rpm, the pressure load is 1-1.5kg, and the thickness size is removed by 0.2mm to 0.35mm.

3. The high-quality surface processing technology for BBO crystal devices according to claim 2 is characterized in that: After sanding, a single-axis machine is used for rough polishing and fine polishing, with W0.25 diamond powder and W0.125 diamond powder used as grinding and polishing media respectively, water as solvent, and a mass concentration of 45%-55%. The polishing turntables used for rough polishing and fine polishing are made of polyurethane and asphalt respectively, with a rotation speed of 20-30rpm, a pressure load of 1-1.5kg, a size reduction of 30-40μm, and a polishing surface flatness of λ / 8, where λ is 632nm±1nm.

4. The high-quality surface processing technology for BBO crystal devices according to claim 3 is characterized in that: After the single-sided polishing is completed, the polished surface is removed by glossy glue, and multiple square small disks are symmetrically placed on a glass substrate with a diameter of 100 mm. Then the same coarse and fine grinding process is repeated on the surface to be polished to remove 0.2 mm to 0.35 mm of the thickness.

5. The high-quality surface processing technology for BBO crystal devices according to claim 4 is characterized in that: After frosting, the rough polishing and fine polishing processes are repeated on the polished surface to make the crystal thickness reach the required size and the flatness of the polished surface reach λ / 8, where λ is 632nm±1nm. After completion, the smooth adhesive surface is debonded by heating at a temperature of 90℃ to 110℃. After cooling the lower plate, the small plate crystal is immersed in gasoline to remove the hot melt adhesive remaining on the crystal surface.

6. A high-quality surface processing process for a BBO crystal device according to claim 5, characterized in that: The crystal is made of β-BaB2O4 blank and processed into thin sheets with cross-sectional dimensions of L×W and thickness of H by means of orientation, cutting, hot glue coating, grinding and polishing, where L, W∈[8mm, 14mm], H∈[0.2mm, 15mm].

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