Two-sided femtosecond laser processing method for glass hemispherical cover

Abstract

The invention belongs to the field of laser processing, and relates to a two-sided femtosecond laser processing method for a glass hemispherical cover, which comprises the following steps of: 1) constructing a processing unit on the glass hemispherical cover; (2) according to the position coordinates obtained through calculation, a pattern track actually needing to be machined is obtained in a parallel projection mode; 3) obtaining a processing path based on the pattern track obtained in the step 2); and (4) machining the machining unit obtained in the step (1) according to the machining path obtained in the step (3). The invention provides the two-sided femtosecond laser processing method for the glass hemispherical cover, which is high in positioning precision and can effectively improve the processing efficiency.

Description

Technical Field

[0001] The invention belongs to the field of laser processing, relates to a laser processing method, and in particular to a double-sided femtosecond laser processing method for a glass hemispherical cover. Background Art

[0002] Glass is a transparent medium with good optical properties. Glass hemispheres play an important role in many fields due to their good optical properties, elegant appearance and wide applicability. Micromachining of glass hemispheres plays an important role in modern science and technology and industry.

[0003] Femtosecond laser refers to a laser with a pulse width at the femtosecond level. Its extremely short pulse duration event allows the laser to process the material in a very fine manner. The pulse of the femtosecond laser has an extremely high peak power, which makes the energy deposition in the material very concentrated, so that the material can be accurately removed or modified. When using a femtosecond laser to micro-process the surface of a glass hemisphere, the heat-affected zone is small, which reduces the damage to the material properties. To process some micro-nanostructure patterns (text, line segments, polygons, arcs, etc.) on the inner and outer surfaces of the glass hemisphere at the same time, and to ensure that the inner and outer processed patterns overlap in the projection normal direction, this requires the processing system to have high-precision centering and positioning capabilities to ensure the symmetry and consistency of the processing effect. However, at present, it is still difficult to maintain the positioning stability of the hemisphere when processing both sides of the hemisphere surface, and the precise docking and processing between the two surfaces is still a technical challenge.

[0004] For example, in the invention application with publication number CN104591549A, a method for processing microarrays on glass surfaces by femtosecond laser pulse sequences is disclosed. The method is to scan microarray patterns through relative movement between the laser focus and the glass material, and to form microarray structures through chemical solutions to enhance laser etching efficiency. Another example is the invention application with publication number CN110066104A, which discloses a device and processing method for laser double-sided processing of glass. The method is to focus the laser beam on the focusing system on the upper and lower sides of the plane glass to be processed by adjusting the position of the mechanical device and the optical element, monitor the focus point position through a CCD camera, and use laser to perform double-sided processing. It is not difficult to find that the existing laser double-sided processing method on the glass surface can only be used for plane processing, and is not applicable to curved objects with inconsistent inner and outer surface features. In addition, the method of double-sided positioning by mechanical devices and optical elements will introduce inherent errors of the mechanical device. For micron-level micro-processing patterns, there are problems such as insufficient processing accuracy and large processing errors. The method of double-sided femtosecond laser processing will introduce multiple positioning errors, unstable double-sided accuracy, and low processing efficiency. Summary of the invention

[0005] In order to solve the above technical problems existing in the background technology, the present invention provides a double-sided femtosecond laser processing method for a glass hemispherical cover with high positioning accuracy and the ability to effectively improve processing efficiency.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A double-sided femtosecond laser processing method for a glass hemispherical cover, characterized in that the double-sided femtosecond laser processing method for a glass hemispherical cover comprises the following steps:

[0008] 1) Building a processing unit on the glass hemispherical cover;

[0009] 2) According to the calculated position coordinates, the pattern trajectory that actually needs to be processed is obtained by parallel projection;

[0010] 3) obtaining a processing path based on the pattern trajectory obtained in step 2);

[0011] 4) Processing the processing unit obtained in step 1) according to the processing path obtained in step 3).

[0012] The wall thickness of the glass hemispherical cover in the above step 1) is 2-3 mm; the specific implementation method of the step 1) is: according to the processing pattern, according to the processing position requirements and the size parameters of the glass hemispherical cover, the position distribution of the processing pattern on the glass hemispherical cover is calculated to obtain the position coordinates.

[0013] The specific implementation of the above step 2) is:

[0014] 2.1) Obtaining a theoretical model of the glass hemispherical cover to be processed;

[0015] 2.2) The position coordinates obtained in step 1) are projected onto the theoretical model of the glass hemispherical cover to be processed obtained in step 2.1) by means of parallel projection to obtain the pattern trajectory actually required to be processed.

[0016] The specific implementation method of the above step 2.2) is:

[0017] 2.2.1) constructing a number of pyramids with the sphere center of the theoretical model of the glass hemispherical cover as the vertex, and performing Boolean operations on the pyramids and the theoretical model of the entire glass hemispherical cover to be processed;

[0018] 2.2.2) extracting the result of Boolean operation of each pyramid and the theoretical model of the glass hemispherical cover to be processed, and obtaining the contour boundary of the pattern actually to be processed;

[0019] 2.2.3) Dividing the contour boundary of the pattern actually required to be processed obtained in step 2.2.2) on the inner surface and the outer surface of the glass hemispherical cover to obtain inner surface processing data and outer surface processing data; the inner surface processing data is the trajectory of the pattern actually required to be processed on the inner surface of the glass hemispherical cover; the outer surface processing data is the trajectory of the pattern actually required to be processed on the outer surface of the glass hemispherical cover; the trajectory of the pattern actually required to be processed on the inner surface of the glass hemispherical cover and the trajectory of the pattern actually required to be processed on the outer surface of the glass hemispherical cover as a whole constitute the trajectory of the pattern actually required to be processed.

[0020] The pyramid is a triangular pyramid, a quadrangular pyramid or a hexagonal pyramid.

[0021] When the pyramid is a quadrangular pyramid, the construction method of the quadrangular pyramid is:

[0022] a) Establish a three-dimensional coordinate system with the center of the theoretical model of the glass hemispherical cover to be processed as the origin, and the coordinate of the center of the sphere is O(0,0,0); divide the radius R of the sphere into equal parts according to the length E of the bottom surface of the quadrangular pyramid; calculate the Z coordinate of the line segment after equal division:

[0023] z i =i*E, i=1,2,…,n

[0024] in:

[0025] n is R / E rounded up; the height used is z i , a plane parallel to the XOY plane intersects with the theoretical model of the glass hemispherical cover to be processed, and a latitudinal intersection line is obtained;

[0026] b) The maximum circumference 2πR of the theoretical model of the glass hemispherical cover to be processed is equally divided along the circumference according to the side length E of the bottom surface of the quadrangular pyramid, and is divided into 2πR / E segments. The zero degree direction on the XOY plane is used as the radial starting position. The plane formed by the pole of the theoretical model of the glass hemispherical cover to be processed, the sphere center point O and the end points of the line segment intersects with the hemisphere to obtain the meridian intersection line; the angle corresponding to each line segment after equal division is θ j :

[0027]

[0028] in:

[0029] m is 2πR / E rounded up, that is, θ m =360°-(m-1)*θ1,θ m ≤θ1;

[0030] θ1 is the angle corresponding to the first line segment after equal division, i.e. when j=1;

[0031] c) Calculate the coordinates of the intersections of all longitude and latitude lines (xi,j ,y i,j ,z i );

[0032]

[0033] in:

[0034] R is the radius of the hemisphere;

[0035] φ i =arccos(z i / R), and the vertex coordinates (x i,j ,y i,j ,z i );

[0036] d) Connect the four vertices on the adjacent contour lines and the center of the sphere to construct a tetrahedron; the vertex of the tetrahedron is the center of the sphere, and the coordinates are O(0,0,0); the coordinates of the four vertices on the bottom are a(x i+1,i ,y i+1,j ,z i+1 )、b(x i+1,j+1 ,y i+1,j+1 ,z i+1 )、c(x i,j+1 ,y i,j+1 ,z i )、d(x i,j ,y i,j ,z i );

[0037] e) For the part of the theoretical model of the glass hemispherical cover to be processed close to the pole, the height of the part of the theoretical model of the glass hemispherical cover to be processed close to the pole is less than or equal to the side length E of the tetrahedron; the surface area of ​​the hemispherical surface close to the pole is calculated as According to the laser processing range, the hemispherical surface close to the pole is equally divided from the zero point direction of the X axis;

[0038] f) Intersecting all the calculated tetrahedrons with the theoretical model of the glass hemisphere cover to be processed, and retaining the same and overlapping parts of all the tetrahedrons and the glass hemisphere.

[0039] The specific implementation of the above step 3) is:

[0040] 3.1) Setting the processing sequence, sorting the pattern tracks obtained in step 2) according to the center point of the processing unit and the direction of the longitude and latitude;

[0041] 3.2) Start from the pole as the first processing unit;

[0042] 3.3) Process a whole row along the latitude direction and take the warp direction as the zero-degree starting point;

[0043] 3.4) Move from the processing block at the end of the previous row to the nearest processing unit in the adjacent weft line until all processing units are traversed.

[0044] The processing sequence in the above step 3.1) is S-type.

[0045] The rows in the above step 3.3) are all processing units with the same latitude on the theoretical model of the glass hemispherical cover to be processed.

[0046] The specific implementation method of transferring from the processing block at the end of the previous row to the nearest processing unit in the adjacent latitude) in the above step 3.4) is: after all the processing units at the same latitude are traversed, traverse from the processing unit with the same longitude as the last block in the processing unit at this latitude but different latitude.

[0047] The advantages of the present invention are:

[0048] The present invention provides a double-sided femtosecond laser processing method for a glass hemispherical cover, comprising: 1) constructing a processing unit on the glass hemispherical cover; 2) obtaining a pattern trajectory actually required to be processed by a parallel projection method according to the calculated position coordinates; 3) obtaining a processing path based on the pattern trajectory obtained in step 2); 4) processing the processing unit obtained in step 1) according to the processing path obtained in step 3). The present invention aims at the requirements of processing efficiency and high processing accuracy that cannot be simultaneously met by the existing curved surface laser processing methods in high-precision processing at the micron processing level. The present invention proposes a double-sided femtosecond laser processing method for a glass hemispherical cover. In view of the inconsistent features of the inner and outer surfaces of the hemispherical body, the inner and outer surfaces of the hemispherical curved surface object are processed simultaneously by a femtosecond laser. The error accumulation and processing time caused by multiple positioning of the existing method are reduced by one positioning, and the consistency of the processing accuracy of the inner and outer surfaces of the femtosecond laser is ensured, so that the overall processing process is more efficient; at the same time, accurate alignment of each processing point is ensured through accurate calculation, thereby achieving high-quality processing effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a schematic diagram of the spherical coordinate calculation principle;

[0050] Figure 2 Schematic diagram of the method for constructing a tetrahedron based on intersection points;

[0051] Figure 3 This is a schematic diagram of the spherical segmentation result;

[0052] Figure 4 It is a schematic diagram of hemispherical Boolean operation;

[0053] Figure 5 Schematic diagram of the contour boundary obtained by clipping the tetrahedron and hemisphere. DETAILED DESCRIPTION

[0054] The purpose of the present invention is to solve the problem that the patterns etched on the inner and outer surfaces of a glass hemisphere processed on both sides by femtosecond laser cannot completely overlap when viewed along the normal direction (due to the thickness of the sphere, there is a distance between the inner and outer surfaces. When observing, the front and back surfaces of the sphere are seen instead of a completely overlapping sphere). A femtosecond laser processing method for the microstructure of the inner and outer surfaces of an ultra-thin glass (the size of the glass hemisphere cover has a wall thickness of 2-3mm and a thickness tolerance of ±0.005mm) hemisphere workpiece is provided.

[0055] A double-sided femtosecond laser processing method for a glass hemispherical cover mainly comprises the following steps:

[0056] 1) Constructing a processing unit on the glass hemisphere cover, specifically: according to the processing pattern, calculating the position distribution of the processing pattern on the glass hemisphere to obtain the position coordinates; preferably, the calculation method is: according to the processing position requirements and the size parameters of the hemisphere, obtaining the position coordinates of the specific processing pattern on the sphere. Calculation is performed using the spherical coordinate formula;

[0057] 2) According to the calculated position coordinates of the processing pattern on the glass hemisphere, the pattern trajectory that actually needs to be processed is calculated by parallel projection; the model (the theoretical model of the glass hemisphere to be processed) and the processing pattern are made into a whole (after the projection calculation, all the point data fall on the spherical surface, and are cut and divided into processing units together with the spherical surface, so they are a whole); the calculation parallel projects the position coordinates to be processed onto the spherical surface, that is, scales the projection points to the spherical surface in proportion;

[0058] When obtaining the pattern trajectory that actually needs to be processed, illustratively, it can be performed in the following manner:

[0059] 2.1) Constructing a number of pyramids along the center of the glass hemisphere, and performing Boolean operations on the pyramids and the theoretical model of the entire glass hemisphere to be processed, and dividing them into a number of pyramids;

[0060] The pyramids constructed in this step include triangular pyramids, quadrangular pyramids, hexagonal pyramids, etc. Since quadrilaterals can completely cover the surface of a sphere and are uniform in size, no other graphics are needed for assistance, so the present invention takes a quadrangular pyramid as an example to illustrate its construction method.

[0061] Specifically, a tetrahedron is constructed along the center of the glass hemisphere, and the input is the radius R of the sphere and the length E of the bottom surface of the tetrahedron to be constructed; further, the method for constructing the tetrahedron is:

[0062] A three-dimensional coordinate system is established with the center of the glass hemisphere as the origin, that is, the coordinate of the center of the sphere is O(0,0,0); the radius R of the sphere is divided equally according to the length E of the base of the tetrahedron (radial direction); the Z coordinate of the line segment after equal division is calculated as:

[0063] z i =i*E, i=1,2,…,n

[0064] Where n is R / E rounded up; the height used is z i , the plane parallel to the XOY plane intersects the hemisphere to obtain the latitudinal intersection line.

[0065] The maximum circumference of the hemisphere 2πR is equally divided along the circumference according to the side length E of the base of the tetrahedron, into 2πR / E segments in total. The zero degree direction on the XOY plane is used as the radial starting position. The plane formed by the pole of the hemisphere, the center point O and the endpoints of the line segment intersects the hemisphere to obtain the meridian intersection line; the angle corresponding to each line segment after equal division is, and the angle is the angle between the lines connecting the two endpoints of the line segment and the center of the circle;

[0066]

[0067] Where: m is 2πR / E rounded up, that is, θ m =360°-(m-1)*θ1,θ m ≤θ1; θ1 is the angle corresponding to the first line segment after equal division, that is, when j=1.

[0068] Calculate the coordinates of the intersections of all longitudes and latitudes; Figure 1 As shown, according to the spherical coordinate calculation formula:

[0069]

[0070] in:

[0071] R is the radius of the hemisphere, z i From the latitudinal intersection line, θ j Calculated from the meridian intersection line, then φ i =arccos(z i / R), from which the vertex coordinates (x i,j ,y i,j ,z i ).

[0072] Connect the four vertices on the adjacent contour lines and the center of the sphere to construct a tetrahedron, such as Figure 2 As shown; the vertex of the tetrahedron is the center of the sphere, with coordinates O(0,0,0); the coordinates of the four vertices of the bottom edge are a(x i+1,i ,y i+1,j ,z i+1 )、b(x i+1,j+1 ,y i+1,j+1 ,z i+1 )、c(x i,j+1 ,y i,j+1 ,z i )、d(xi,j ,y i,j ,z i ).

[0073] For the part of the sphere close to the pole, such as Figure 3 As shown, the part of the sphere close to the pole (such as Figure 3 The height of the topmost unbuilt tetrahedron shown (the distance from the base to the pole along the meridian direction) is less than or equal to the side length E of the tetrahedron; calculate its surface area (near the pole in the hemisphere) as According to the laser processing range, it is divided equally from the zero point of the X-axis (such as four or eight equal parts, which is smaller than the processing range. Due to the limitation of the single processing width in laser processing, it is necessary to perform regional processing. Equal division is the simplest regional division method).

[0074] Make an intersection of all the calculated tetrahedrons and the glass hemisphere processing model, and keep all the parts that are the same and overlapped between the tetrahedrons and the glass hemisphere. Extract the parts obtained by cutting each pyramid and the glass hemisphere, and extract the contour boundary (connect the four vertices of the calculated pyramid bottom surface in pairs, which is the boundary of the contour); divide the contained part of each pyramid into inner and outer surfaces; the specific division is that for the constructed single pyramid, it will intersect with the inner and outer surfaces of the hemisphere, and divide the inner and outer surfaces by calculating the distance between the intersection and the center of the sphere, and the inner surface is closer to the center of the sphere; divide the data obtained by cutting all pyramids (the surface obtained by cutting the pyramid is a polygon) into inner and outer surfaces, and obtain inner surface processing data and outer surface processing data; the inner surface processing data is the trajectory of the pattern that actually needs to be processed on the inner surface of the glass hemisphere cover; the outer surface processing data is the trajectory of the pattern that actually needs to be processed on the outer surface of the glass hemisphere cover; the trajectory of the pattern that actually needs to be processed on the inner surface of the glass hemisphere cover and the trajectory of the pattern that actually needs to be processed on the outer surface of the glass hemisphere cover constitute the trajectory of the pattern that actually needs to be processed.

[0075] 3) Calculate the processing path

[0076] 3.1) Set the processing sequence, sort according to the center point of the processing unit and the direction of the longitude and latitude; the processing sequence can be set to S type:

[0077] 3.2) Start from the pole as the first processing unit;

[0078] 3.3) Process a whole row along the latitude direction and with the meridian direction as the zero-degree starting point; a row refers to all processing units with the same latitude in the hemisphere;

[0079] 3.4) Move from the processing block at the end of the previous row to the nearest processing unit in the adjacent latitude until all processing units are traversed; wherein, the method of moving is: after all processing units at the same latitude are traversed, traverse from the processing unit with the same longitude as the last block of processing units at this latitude but different latitude.

[0080] 3.5) Assign the processing data of the inner surface group and the processing data of the outer surface group to different light knives.

[0081] 4) Processing the inner and outer surface processing units according to the processing path of step 3).

[0082] Exemplarily, according to the processing results, the processing quality can also be tested. For example, after the processing is completed, the overlap rate of the outline width of the graphics element on the inner and outer surfaces of the processing pattern is detected; the double-sided line width overlap error ≤2μm is to meet the requirements; detect whether the processing graphics element line width meets the requirements, if the minimum line width is 10μm, the accuracy is ±1μm, then the processing requirements are met; the size of the glass hemispherical cover sample: outer diameter 145mm, height 50mm, spherical radius 80mm, thickness tolerance ±0.005mm, wall thickness 2.5~3mm. Processing requirements: double-sided curved surface superstructure surface unit, inner and outer part of the micro-nano structure unit projection overlap, line width is submicron to micron level. 1. Double-sided line width overlap error ≤2μm; 2. Minimum line width 10μm, accuracy ±1μm; 3. Line height requirement ≥3μm.

Claims

1. A double-sided femtosecond laser processing method for a glass hemispherical cover, characterized in that: The double-sided femtosecond laser processing method of the glass hemispherical cover comprises the following steps: 1) Building a processing unit on the glass hemispherical cover; 2) According to the calculated position coordinates, the pattern trajectory that actually needs to be processed is obtained by parallel projection; 3) obtaining a processing path based on the pattern trajectory obtained in step 2); 4) Processing the processing unit obtained in step 1) according to the processing path obtained in step 3).

2. The double-sided femtosecond laser processing method of a glass hemispherical cover according to claim 1, characterized in that: The wall thickness of the glass hemispherical cover in step 1) is 2-3 mm. The specific implementation method of step 1) is: according to the processing pattern, the processing position requirements and the size parameters of the glass hemispherical cover, the position distribution of the processing pattern on the glass hemispherical cover is calculated to obtain the position coordinates.

3. The double-sided femtosecond laser processing method of a glass hemispherical cover according to claim 2, characterized in that: The specific implementation method of step 2) is: 2.1) Obtaining a theoretical model of the glass hemispherical cover to be processed; 2.2) The position coordinates obtained in step 1) are projected onto the theoretical model of the glass hemispherical cover to be processed obtained in step 2.1) by means of parallel projection to obtain the pattern trajectory actually required to be processed.

4. The double-sided femtosecond laser processing method of a glass hemispherical cover according to claim 3, characterized in that: The specific implementation method of step 2.2) is: 2.2.1) constructing a number of pyramids with the sphere center of the theoretical model of the glass hemispherical cover as the vertex, and performing Boolean operations on the pyramids and the theoretical model of the entire glass hemispherical cover to be processed; 2.2.2) extracting the result of Boolean operation of each pyramid and the theoretical model of the glass hemispherical cover to be processed, and obtaining the contour boundary of the pattern actually to be processed; 2.2.3) Dividing the contour boundary of the pattern actually required to be processed obtained in step 2.2.2) on the inner surface and the outer surface of the glass hemispherical cover to obtain inner surface processing data and outer surface processing data; the inner surface processing data is the trajectory of the pattern actually required to be processed on the inner surface of the glass hemispherical cover; the outer surface processing data is the trajectory of the pattern actually required to be processed on the outer surface of the glass hemispherical cover; the trajectory of the pattern actually required to be processed on the inner surface of the glass hemispherical cover and the trajectory of the pattern actually required to be processed on the outer surface of the glass hemispherical cover as a whole constitute the trajectory of the pattern actually required to be processed.

5. The double-sided femtosecond laser processing method of a glass hemispherical cover according to claim 4, characterized in that: The pyramid is a triangular pyramid, a quadrangular pyramid or a hexagonal pyramid.

6. The double-sided femtosecond laser processing method of a glass hemispherical cover according to claim 5, characterized in that: When the pyramid is a quadrangular pyramid, the construction method of the quadrangular pyramid is: a) Establish a three-dimensional coordinate system with the center of the theoretical model of the glass hemispherical cover to be processed as the origin, and the coordinate of the center of the sphere is O(0,0,0); divide the radius R of the sphere into equal parts according to the length E of the bottom surface of the quadrangular pyramid; calculate the Z coordinate of the line segment after equal division: z i =i*E,i=1,2,…,n in: n is R / E rounded up; the height used is z i , a plane parallel to the XOY plane intersects with the theoretical model of the glass hemispherical cover to be processed, and a latitudinal intersection line is obtained; b) The maximum circumference 2πR of the theoretical model of the glass hemispherical cover to be processed is equally divided along the circumference according to the side length E of the bottom surface of the quadrangular pyramid, and is divided into 2πR / E segments. The zero degree direction on the XOY plane is used as the radial starting position. The plane formed by the pole of the theoretical model of the glass hemispherical cover to be processed, the sphere center point O and the end points of the line segment intersects with the hemisphere to obtain the meridian intersection line; the angle corresponding to each line segment after equal division is θ j : in: m is 2πR / E rounded up, that is, θ m =360°-(m-1)*θ1,θ m ≤θ1; θ1 is the angle corresponding to the first line segment after equal division, i.e. when j=1; c) Calculate the coordinates of the intersections of all longitude and latitude lines (x i,j ,y i,j ,z i ); in: R is the radius of the hemisphere; φ i =arccos(z i / R), and the vertex coordinates (x i,j ,y i,j ,z i ); d) Connect the four vertices on the adjacent contour lines and the center of the sphere to construct a tetrahedron; the vertex of the tetrahedron is the center of the sphere, and the coordinates are O(0,0,0); the coordinates of the four vertices on the bottom are a(x i+1,i ,y i+1,j ,z i+1 )、b(x i+1,j+1 ,y i+1,j+1 ,z i+1 )、c(x i,j+1 ,y i,j+1 ,z i )、d(x i,j ,y i,j ,z i ); e) For the part of the theoretical model of the glass hemispherical cover to be processed close to the pole, the height of the part of the theoretical model of the glass hemispherical cover to be processed close to the pole is less than or equal to the side length E of the tetrahedron; the surface area of ​​the hemispherical surface close to the pole is calculated as According to the laser processing range, the hemispherical surface close to the pole is equally divided from the zero point direction of the X axis; f) Intersecting all the calculated tetrahedrons with the theoretical model of the glass hemisphere cover to be processed, and retaining the same and overlapping parts of all the tetrahedrons and the glass hemisphere.

7. The double-sided femtosecond laser processing method of a glass hemispherical cover according to claim 6, characterized in that: The specific implementation method of step 3) is: 3.1) Setting the processing sequence, sorting the pattern tracks obtained in step 2) according to the center point of the processing unit and the direction of the longitude and latitude; 3.2) Start from the pole as the first processing unit; 3.3) Process a whole row along the latitude direction and take the warp direction as the zero-degree starting point; 3.4) Move from the processing block at the end of the previous row to the nearest processing unit in the adjacent weft line until all processing units are traversed.

8. The double-sided femtosecond laser processing method of a glass hemispherical cover according to claim 7, characterized in that: The processing sequence in step 3.1) is S-type.

9. The double-sided femtosecond laser processing method of a glass hemispherical cover according to claim 8, characterized in that: The rows in step 3.3) are all processing units with the same latitude on the theoretical model of the glass hemispherical cover to be processed.

10. The double-sided femtosecond laser processing method of a glass hemispherical cover according to claim 9, characterized in that: The specific implementation method of transferring from the processing block at the end of the previous row to the nearest processing unit in the adjacent latitude in the step 3.4) is: after all the processing units at the same latitude are traversed, traverse from the processing unit with the same longitude as the last block in the processing unit at this latitude but different latitude.

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