A processing method for regular micro-nano structures on the glass surface

Abstract

The present invention relates to a processing method for regular micro-nano structures on the glass surface. The method includes using a quadrangular pyramid diamond tool to successively scribe on the glass surface along a first direction with the edge of the tool facing forward, obtaining a plurality of first grooves arranged side by side; using the quadrangular pyramid diamond tool to successively scribe on the glass surface along a second direction, where the first direction and the second direction are perpendicular to each other, and with the face of the tool facing forward during scribing, obtaining a plurality of second grooves arranged side by side; and the intersection of the plurality of first grooves and the plurality of second grooves forms a pyramid structure on the glass surface. The pushing effect when the edge faces forward promotes the plastic flow of the material, increasing the height and aspect ratio of the structure under the same load. Then, a 90° intersection is used, and the front tool face shears and removes the material when the face faces forward, avoiding the blockage of the groove structure caused by material flow. It is possible to obtain an equivalent metamorphic layer with a continuously varying refractive index on the glass surface, improve the light transmittance at all angles of incidence in the visible light band, and reduce the reflectivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical glass processing, and particularly relates to a method for processing regular micro-nano structures on the glass surface. Background Art

[0002] Optical glass has a high transmittance and a low reflectance in the visible light band. However, in optical components, when the light source passes through multiple interfaces with mismatched refractive indices and large-angle incidence, internal reflection easily occurs, reducing the actual light output ratio. In addition, in an environment with a strong light source, specular reflection occurring at the surface interface will also cause a glare effect, seriously threatening the eyesight health of users. Therefore, it is necessary to further improve its transmittance at any incident angle in the visible light band and reduce the reflectance. By directly preparing regular micro-nano structures with specific periods and shapes on the glass surface, when the characteristic size of the micro-structure is smaller than the light wavelength, the incident light is equivalent to passing through a transition layer with a continuously varying refractive index, completely eliminating the reflection phenomenon at the surface interface, and effectively improving the light output ratio of optical components and suppressing the glare effect.

[0003] Traditional antireflection methods are to cover one or more antireflection films on the surface of optical elements, and use destructive interference of reflected light to reduce surface reflection. According to the refractive index of the substrate, the refractive index of a single layer or multiple layers of thin films at the corresponding target wavelength is designed, and then the thin film is prepared by physical or chemical deposition and attached to the material surface, which can effectively improve the transmittance within a certain range, but can only achieve antireflection at small angles and specific wavelengths, and there are problems such as interface bonding, thermal expansion coefficient adaptation, and refractive index matching between the film layer and the substrate. Nanoimprint technology can relatively easily prepare large-area micro-structures, effectively improving production efficiency, but has high requirements for the preparation of templates, and the processing of micro-nano scale templates is difficult and costly. Laser ablation processing of micro-structures is widely used for its advantages of low cost, high efficiency, and high precision, but it is necessary to consider the influence of the spot diameter during laser processing on the structure period and defects caused by factors such as structural deformation, material sputtering, and composition modification due to the thermal effect during ablation. It is generally believed that the method of mechanical removal caused by the interference between the tool and the material can ensure the surface shape accuracy of the processed surface and micro-structures. However, glass is a hard and brittle material, so how to ensure the integrity of the regular micro-structures obtained during mechanical processing and the absence of cracks on the surface / subsurface is still an unsolved problem. Summary of the Invention

[0004] Aiming at the technical problems existing in the prior art, the purpose of the present invention is to provide a method for processing regular micro-nano structures on the glass surface, which can obtain an equivalent metamorphic layer with a continuously varying refractive index on the glass surface, effectively eliminate the interface between air and the medium, improve the light transmittance at all angles of incidence in the visible light band, and reduce the reflectance.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A processing method for regular micro-nano structures on the glass surface includes the following steps:

[0007] Use a quadrangular pyramid diamond tool to scratch the glass surface sequentially along the first direction, with the edge of the tool facing forward during scratching, to obtain a plurality of first grooves arranged side by side;

[0008] Use a quadrangular pyramid diamond tool to scratch the glass surface sequentially along the second direction, where the first direction and the second direction are perpendicular to each other, with the face of the tool facing forward during scratching, to obtain a plurality of second grooves arranged side by side;

[0009] The intersection of the plurality of first grooves and the plurality of second grooves forms a pyramid structure on the glass surface.

[0010] Furthermore, the actual scratching depth of the first groove is h s1 ,

[0011]

[0012] wherein, the edge angle of the quadrangular pyramid diamond tool is α, the normal force applied during processing is P, the hardness of the glass is H, and the elastic recovery rate of the glass when scratching with the edge facing forward is μ1.

[0013] Furthermore, the actual scratching depth of the second groove is h s2 ,

[0014]

[0015] wherein, the face angle of the quadrangular pyramid diamond tool is β, and the elastic recovery rate of the glass during scratching with the face facing forward is μ2.

[0016] Furthermore, the residual depth h of the first groove r1 is

[0017] h r1 =(1 - μ1)h s1 .

[0018] Furthermore, the residual depth h of the second groove r2 is

[0019] h r2 =(1 - μ2)h s2 .

[0020] Furthermore, the groove width D between adjacent first grooves s1 is

[0021]

[0022] Furthermore, the groove width D between adjacent second grooves s2 is

[0023]

[0024] Furthermore, both the first groove and the second groove are formed by controlling the movement of the glass using a displacement stage.

[0025] Furthermore, before scribing the glass, the following steps are also included: cleaning the glass using ultrasonic waves and then drying it.

[0026] Furthermore, after ultrasonic cleaning, the following steps are also included: adjusting the flatness of the glass surface using a leveling device.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] First, use a tetrahedral diamond tool to scribe the glass surface along the first direction in sequence with the edge facing forward. When the edge faces forward during machining, the pushing effect of the two side faces of the tool on the material can promote the plastic flow of the material, resulting in a structure with a greater height and aspect ratio of the material accumulation on both sides of the first groove; then use the tool with the face facing forward to scribe the glass surface along the second direction in sequence. When the face faces forward during machining, the front cutting face of the tool shears and removes the material without causing material accumulation, so the structure height is relatively low.

[0029] Since the first direction and the second direction of tool machining are perpendicular to each other, during the crossing process, due to the accumulation during machining with the edge facing forward, the original first groove structure will be blocked by the material pushed up by the second groove during the second scribing and it is difficult to form a structure. Therefore, it is necessary to use the face-facing-forward machining method during the second machining to obtain a regular three-dimensional structure with high profile accuracy. The present invention first uses the pushing effect when the edge faces forward to promote the plastic flow of the material and increase the height and aspect ratio of the structure under the same load, and then uses the shearing removal of the front cutting face of the tool by machining with the face facing forward at a 90° crossing to avoid the blockage of the groove structure caused by material flow, so as to obtain an equivalent metamorphic layer with a continuously varying refractive index on the glass surface, effectively eliminating the interface between air and the medium, improving the light transmittance at all angles of incidence in the visible light band, and reducing the reflectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the shape of the indenter and the structure of the tip of a tetrahedral diamond tool.

[0031] Figure 2 It is a schematic diagram of the machining process of a tetrahedral diamond tool on the glass surface.

[0032] Figure 3 It is a schematic diagram of the structure of a machining device for a tetrahedral diamond tool.

[0033] Figure 4 It is a schematic diagram of machining with the edge of the tool facing forward.

[0034] Figure 5 Schematic diagram of the tool facing forward for machining.

[0035] Figure 6 Schematic diagram of the groove structure formed by tool scribing machining.

[0036] Figure 7 Schematic diagram of the pyramid array structure formed by tool scribing machining.

[0037] Figure 8 Measurement and comparison of glass transmittance.

[0038] In the figure:

[0039] 1 - Rotary table, 2 - Leveling device, 3 - Displacement platform, 4 - Diamond tool, 5 - Fixture, 6 - Glass workpiece, 7 - Force sensor, 8 - Moving lead screw. Specific implementation manner

[0040] The key points of the present invention lie in the design of the structural period and height. Considering the elastic recovery phenomenon of hard and brittle materials in plastic processing, the structure is designed and predicted according to the applied load to obtain a more accurate three-dimensional micro-nano structure. In addition, by analyzing the influence of the edge-facing-forward machining and the face-facing-forward machining on the material removal form, it is found that when machining with the edge facing forward, the pushing effect of the two side faces on the material can promote the plastic flow of the material, resulting in a structure with a greater height and aspect ratio of the material accumulation on both sides of the groove. While when machining with the face facing forward, the cutting tool rake face shears and removes the material without causing material accumulation, so the structure height is relatively low. However, during the intersection process, due to the accumulation during the edge-facing-forward machining, the original groove structure will be blocked by the material pushed up twice and it is difficult to form a structure. Therefore, it is necessary to use the face-facing-forward machining method in the second machining to obtain a regular three-dimensional structure with high profile accuracy. And a truly micro-nano scale structure can be obtained by using the tip of the diamond. At present, many mechanical removal machining methods for micro-nano structures are limited by the tool size and it is difficult to achieve the machining of micro-nano structures, and it is also difficult to ensure that there are no cracks in the machined samples when directly machining hard and brittle materials.

[0041] Based on the Hertz contact theory, the present invention constructs a load-depth theoretical model considering elastic recovery for the four-sided pyramid diamond tool 4 in different orientations by elastoplastic mechanics to design and predict the dimensional characteristics of machining three-dimensional micro-nano structures. In addition, by analyzing the differences in material removal methods during edge-facing-forward and face-facing-forward machining through experimental phenomena, first, the pushing effect during edge-facing-forward machining is used to promote the plastic flow of the material and increase the height and aspect ratio of the structure under the same load, and then a 90° intersection is used to shear and remove the material on the cutting tool rake face during face-facing-forward machining to avoid the blockage of the groove structure caused by material flow.

[0042] The present invention will be further described in detail below.

[0043] A processing method for regular micro-nano structures on the glass surface includes the following steps:

[0044] Use a quadrangular pyramid diamond tool 4 to scribble on the glass surface in the first direction in sequence. When scribbling, the edge of the diamond tool 4 faces forward to obtain a plurality of first grooves arranged side by side.

[0045] Use a quadrangular pyramid diamond tool 4 to scribble on the glass surface in the second direction in sequence. The first direction and the second direction are perpendicular to each other. When scribbling, the face of the diamond tool 4 faces forward to obtain a plurality of second grooves arranged side by side.

[0046] A plurality of first grooves and a plurality of second grooves intersect on the glass surface to form a pyramid structure.

[0047] Specifically, the indenter shape and tip of the quadrangular pyramid diamond tool 4 are as Figure 1 shown. The edge angle of the quadrangular pyramid diamond tool 4 is α, and the face angle is β.

[0048] During processing, the normal force applied by the diamond tool 4 is P, the feed rate is v, and the material hardness is H. When scribbling with the edge facing forward, the elastic recovery rate of the glass is μ1, and when scribbling with the face facing forward, the elastic recovery rate of the glass is μ2.

[0049] As Figure 2 shown, the actual scribing depth during the processing is represented by h s , including the actual scribing depth h s1 of the first groove and the actual scribing depth h s2 of the second groove.

[0050] The residual depth considering the elastic recovery of the workpiece after scribing is represented by h r , including the residual depth h r1 of the first groove and the residual depth h r2 of the second groove.

[0051] During the scribing process in the same direction, after each scribing is completed, use the displacement platform 3 to control the glass to move the groove width D s and repeat scribing to obtain a groove array. The groove width D s includes the groove width D s1 between adjacent first grooves and the groove width D s2 between adjacent second grooves.

[0052] Then, the relationship between the actual scribing depth h s1 and the residual depth h r1 during the edge-forward processing is:

[0053] h r1 = (1 - μ1)h s1;

[0054] According to Hertz theory, the actual machining depth h during the edge-forward machining can be calculated as: s1 For:

[0055]

[0056] Then, from the geometric relationship, the adjacent first groove pitch D during the edge-forward machining can be obtained as: s1 For:

[0057]

[0058] Similarly, for the face-forward machining, the relationship between the actual scratching depth h and the residual depth h is: s2 And the residual depth h r2 Is:

[0059] h r2 =(1 - μ2)h s2 ;

[0060] According to Hertz theory, the actual machining depth h during the face-forward machining can be calculated as: s2 For:

[0061]

[0062] Then, from the geometric relationship, the adjacent second groove pitch D during the face-forward machining should be: s2 Should be:

[0063]

[0064] Thus, the height, period, shape and other characteristics of the processed three-dimensional structure can be accurately designed.

[0065] In this embodiment, as Figure 3 Shown, the processing device includes a rotating table 1, a leveling device 2, a displacement platform 3, a fixture 5, a moving lead screw 8 and a force sensor 7. Among them, the rotating table 1 is used for horizontal rotation. The leveling device 2 is arranged on the rotating table 1 and is used to adjust the flatness of the glass surface. The displacement platform 3 is arranged on the leveling device 2 and is used to control the movement of the glass workpiece 6 in the y direction, that is, to control the groove pitch and the target structure period. The fixture 5 is arranged on the displacement platform 3 and is used to clamp the glass workpiece 6.

[0066] Before processing, the glass workpiece 6 is ultrasonically cleaned in an alcohol solution for ten minutes, dried on the surface, and then installed and fixed.

[0067] The four-sided pyramid diamond tool 4 is fixed on the force sensor 7 and is used to apply and collect the normal force during the processing, and is driven by the moving lead screw 8 to complete the feed on the glass surface.

[0068] After one feed machining is completed, the tool returns to the initial position, and at the same time, the displacement platform 3 moves a groove pitch Ds, and machining is carried out again. By repeating this process, the groove array pitch can be obtained. After all the groove structures in one direction are machined, the workpiece is rotated 90° by the rotating table 1, and machining in the cross direction is carried out again. Finally, a complete pyramid micro-nano structure with better surface accuracy can be obtained.

[0069] It should be noted that when machining the micro-structure, the feeding in the first direction needs to be carried out in the way of scribing with the edge facing forward, while the machining in the second direction after rotating 90° needs to be carried out with the face facing forward. The two machining methods are as Figure 4 , Figure 5 shown.

[0070] Figure 6 , Figure 7 shown. When a load of 26 mN is applied by using this method, the first groove pitch is 3.2 μm when scribing with the edge facing forward, the second groove pitch is 2.5 μm when scribing with the face facing forward, and the structure height is 320 nm. As Figure 8 shown, by testing its transmittance in the visible light band, it is found that both the groove structure and the pyramid structure can improve its transmittance, and the transmittance of the pyramid structure is the highest.

[0071] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A processing method for regular micro-nano structures on the glass surface, characterized in that: The method includes the following steps: using a quadrangular pyramid diamond tool to scratch the glass surface successively along a first direction, with the edge of the tool facing forward during the scratching process, to obtain a plurality of first grooves arranged side by side; using a quadrangular pyramid diamond tool to scratch the glass surface successively along a second direction, where the first direction and the second direction are perpendicular to each other, with the face of the tool facing forward during the scratching process, to obtain a plurality of second grooves arranged side by side; a plurality of first grooves and a plurality of second grooves intersect on the glass surface to form a pyramid structure; The actual etching depth of the first groove is h s1 ; wherein, the edge angle of the quadrangular pyramid diamond tool is α, the normal force applied during processing is P, the hardness of the glass is H, and the elastic recovery rate of the glass when scratching with the edge facing forward is μ1; The actual etching depth of the second groove is h s2 , wherein, the face angle of the quadrangular pyramid diamond tool is β, and the elastic recovery rate of the glass when scratching with the face facing forward is μ2; Residual depth h of the first groove r1 is h r1 =(1 - μ1)h s1 ; The residual depth h of the second groove r2 is, h r2 = (1 - μ2)h s2 ; The groove width D between adjacent first grooves s1 is The groove width D between adjacent second grooves s2 is 2. The processing method of the regular micro-nano structure on the glass surface according to claim 1, characterized in that: Both the first grooves and the second grooves are realized by controlling the movement of the glass using a displacement platform.

3. A processing method for regular micro-nano structures on the glass surface according to claim 1, characterized in that: Before the glass is scratched, the following steps are further included: cleaning the glass using ultrasound and then drying it.

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