Method for processing anisotropic light guiding microstructure

Abstract

The present application belongs to the field of laser processing, and relates to a microstructure processing method, comprising the following steps: 1) obtaining a target groove type of a special-shaped light guide microstructure, and determining a required light spot shape of the target groove type; 2) modulating the light spot shape determined in step 1) based on an ultrafast laser processing system; 3) setting laser parameters and galvanometer scanning parameters of the ultrafast laser processing system according to the light spot shape obtained in step 2), and completing processing of an approximate target groove type; 4) detecting the processing effect of the approximate target groove type obtained in step 3) by using a 3D profiler, obtaining a detection result, and repeatedly executing steps 2) and 3) according to the difference between the detection result and an actual target groove type, and finally completing processing of the special-shaped light guide microstructure. The special-shaped light guide microstructure processing method can facilitate processing of a special-shaped light guide point and improve processing efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of laser processing, and relates to a microstructure processing method, in particular to a processing method of a special-shaped light guide microstructure. BACKGROUND

[0002] A light guide plate is a structure that uses optical-grade acrylic (PMMA) plate material, makes microstructures on the surface thereof through laser or other process methods, and finally realizes diffusion of point light source into area light source, and has the advantages of high light guide rate, energy saving, environmental protection, lightness, etc., and is widely used in liquid crystal displays, various lighting equipment, advertising light boxes, optical instruments, artistic atmosphere lamps, home lighting, and many other fields.

[0003] With the development of information technology, flat panel displays have put forward the demand for thinner, lower energy consumption, and higher light efficiency of light guide plates, and therefore it is necessary to develop high-gain light guide plates. The nanosecond laser dot processing technology in the prior art is relatively mature, but the processing graphics are relatively single, and only conical blind grooves can be processed, and it is difficult to process special-shaped light guide points, and cannot meet the demand for high-gain light guide plates. The V-vutting process can process special-shaped light guide points by customizing special tool heads, but in the actual production process, a single mold needs millions of screen points, and there is a wear problem, which leads to a very low yield of the final product, and seriously affects the mass production of high-gain light guide plates. SUMMARY

[0004] In order to solve the above technical problems in the background art, the present application provides a processing method of a special-shaped light guide microstructure which can facilitate processing of special-shaped light guide points and improve processing efficiency.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] A processing method of a special-shaped light guide microstructure, characterized in that the processing method of the special-shaped light guide microstructure comprises the following steps:

[0007] 1) obtaining a target groove type of a special-shaped light guide microstructure, and determining a light spot shape required by the target groove type;

[0008] 2) modulating a light spot shape determined in step 1) based on a superfast laser processing system;

[0009] 3) setting laser parameters and galvanometer scanning parameters of the superfast laser processing system according to the light spot shape obtained in step 2), and completing processing of an approximate target groove type;

[0010] 4) using 3D profiler to detect the approximate target groove type processing effect obtained in step 3), obtaining a detection result, and repeatedly performing step 2) and step 3) according to the difference between the detection result and the actual target groove type until the actual processing effect reaches the target groove type, and completing the processing of the special light guide microstructure.

[0011] The target groove in step 1) is a crescent-shaped groove or a rectangular groove.

[0012] When the target groove is a crescent-shaped groove, the specific implementation of the light spot shape required for determining the target groove type is to use a Gaussian light spot, improve the light spot roundness, and optimize the light beam energy distribution state to obtain the required light spot shape; when the target groove is a rectangular groove, the specific implementation of the light spot shape required for determining the target groove type is to shape the light spot to have an asymmetric distribution of light spot energy curves to obtain the required light spot shape.

[0013] The superfast laser processing system includes a laser, an optical path transmission system, a beam modulation module, a galvanometer scanning system, a light spot shape auxiliary detection module, and an industrial computer. The light spot shape auxiliary detection module includes a beam quality analyzer. The laser generates superfast laser, which enters the beam modulation module, the galvanometer scanning system, and the light spot shape auxiliary detection module in sequence through the optical path transmission system. The light spot shape auxiliary detection module feeds back the beam modulation state to the industrial computer. The industrial computer outputs a modulation signal to the beam modulation module to realize a specific light spot state according to the real-time feedback beam modulation state. The industrial computer controls the galvanometer scanning system to complete the processing of the target groove type.

[0014] The specific implementation of step 2) is to use the beam phase shaping of the beam modulation module of the superfast laser processing system, detect the light spot shape through the beam quality analyzer of the light spot shape auxiliary detection module, and finally modulate the light spot shape determined in step 1) through online closed-loop testing.

[0015] When the target groove is a rectangular groove, the specific implementation of step 3) is:

[0016] a.1) controlling the groove depth and length by controlling the power of the superfast laser;

[0017] a.2) setting the processing track of the rectangular groove, determining the light spot energy distribution and light spot length through the beam modulation module of the superfast laser processing system, adjusting the groove width and inner wall angle through the beam modulation module, and optimizing the groove roughness through the beam modulation module, and finally processing the target groove type of the approximate rectangular groove.

[0018] The specific implementation of optimizing the groove roughness through the beam modulation module is to adjust the power of the superfast laser through the beam modulation module to optimize the smoothness of the energy step.

[0019] The specific implementation mode of step 3) is as follows when the target groove is a crescent-shaped groove:

[0020] b.1) Process the micro groove by setting different focal point positions, detect the inner wall angle of the micro groove, and preliminarily determine the processing focal point; the processing focal point is the Z-axis coordinate corresponding to the minimum size of the focused light spot;

[0021] b.2) Based on the processing focal point obtained in step b.1), adjust the fundamental frequency and power of the ultrafast laser;

[0022] b.3) Based on the fundamental frequency and power of the ultrafast laser obtained in step b.2), set the processing track, process the micro groove, measure the inner wall angle of the actual micro groove, and adjust the overlap rate according to the inner wall angle;

[0023] b.4) Based on the result obtained in step b.3), set the processing speed, measure the roughness of the micro groove, and continuously optimize the laser parameters and galvanometer scanning parameters of the ultrafast laser processing system to finally process and form the target groove type of the approximate crescent-shaped groove.

[0024] The processing track in the above step b.3) is formed by gradually moving from the outside of the crescent-shaped groove to the inside in a spiral manner.

[0025] The processing track of the rectangular groove in step b.2) is formed by single straight line reciprocating motion when the target groove is a rectangular groove.

[0026] The advantages of the present application are:

[0027] The present application provides a processing method of a special-shaped light guide microstructure, comprising: 1) obtaining a target groove type of a special-shaped light guide microstructure, and determining the required light spot shape of the target groove type; 2) modulating the light spot shape determined in step 1) based on an ultrafast laser processing system; 3) setting the laser parameters and galvanometer scanning parameters of the ultrafast laser processing system according to the light spot shape obtained in step 2), and completing the processing of the approximate target groove type; 4) detecting the processing effect of the approximate target groove type obtained in step 3) by using a 3D profiler, obtaining a detection result, and repeatedly executing steps 2) and 3) according to the difference between the detection result and the actual target groove type, and finally completing the processing of the special-shaped light guide microstructure. The present application can process new high-gain light guide points by using ultrafast laser, and has high processing efficiency. In addition, various special groove types can be customized, a special product library is established, which is friendly to the mass production stage and can realize rapid changeover. Compared with the traditional point collision process for producing high-gain light guide plates, the production yield of the present application is much higher than that of the traditional method. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a schematic diagram of a special-shaped light guide microstructure obtained based on the processing method of the special-shaped light guide microstructure provided by the present application;

[0029] Figure 2 is a flow chart of the processing method of the special-shaped light guide microstructure provided by the application;

[0030] Figure 3 is a schematic diagram of the required modulation light spot state according to the crescent groove;

[0031] Figure 4 is a schematic diagram of the required modulation light spot state according to the rectangular groove;

[0032] Figure 5 is a schematic diagram of the processing track of the crescent groove. DETAILED DESCRIPTION

[0033] In order to solve many problems in the production process of products from the root, the ultrafast laser processing technology is introduced. First, the laser is a non-contact processing without loss and will not cause secondary scratches on the surface of the sample; secondly, in the product change process, it is very convenient, only the parameter library needs to be called; finally, when processing different models of products, the traditional process needs to customize the tool bit, and the laser only needs to modify the parameters. Therefore, there are many obvious advantages in introducing the laser process.

[0034] The application provides a processing method of a special-shaped light guide microstructure, comprising the following steps:

[0035] 1) obtaining a target groove type of the special-shaped light guide microstructure, and determining a required light spot shape of the target groove type; wherein, referring to Figure 1 , the target groove is a crescent groove or a rectangular groove, of course, it can also be constructed based on the method provided by the application, such as peanut appearance, W-shaped microgroove and various groove types, for example, a variety of special groove types can be customized, a special product library is established, which is friendly to the mass production stage and can realize rapid changeover. Referring to Figure 3 , when the target groove is a crescent groove, the specific implementation manner of determining the required light spot shape of the target groove type is: using a Gaussian light spot, improving the light spot roundness and optimizing the light beam energy distribution state to obtain the required light spot shape; referring to Figure 4 , when the target groove is a rectangular groove, the specific implementation manner of determining the required light spot shape of the target groove type is: shaping the light spot into a light spot energy curve asymmetric distribution to obtain the required light spot shape.

[0036] 2) modulating the light spot shape determined in step 1) based on the ultrafast laser processing system; Specifically, the light beam phase shaping of the light beam modulation module of the ultrafast laser processing system is used, the light spot shape is detected by the light beam quality analyzer, and the online closed loop test is finally modulated to obtain the light spot shape determined in step 1). Referring to Figure 2The ultrafast laser processing system adopted by the application comprises a laser, an optical path transmission system, a beam modulation module, a galvanometer scanning system, a light spot shape auxiliary detection module and an industrial computer; the light spot shape auxiliary detection module comprises a beam quality analyzer; the laser generates ultrafast laser, which enters the beam modulation module, the galvanometer scanning system and the light spot shape auxiliary detection module in sequence through the optical path transmission system; the light spot shape auxiliary detection module feeds back the beam modulation state to the industrial computer; the industrial computer outputs a modulation signal to the beam modulation module according to the real-time feedback beam modulation state to realize a specific light spot state; and the industrial computer controls the galvanometer scanning system to complete the processing of the target groove type. The ultrafast laser processing system adopted by the application has the beam modulation function on the hardware, and can match the corresponding light spot shape according to the actual groove type requirement. The CAM software function development is carried out on the software aspect, and the variable overlap rate processing between different amplitudes of the galvanometer is realized through the software control algorithm optimization, so that the product processing is finally ensured without splicing marks, and the expected target is achieved. In the large-amplitude processing process, the processing precision is ensured through the high-precision cooperation of each component of the equipment, and the corresponding parameters can be set separately in the later development of different models of products, and the process library is gradually improved. At present, in the process development process, firstly, the raw material to be processed is obtained, the corresponding beam modulation state is preliminarily matched according to the actual groove type requirement, the corresponding process parameters are set, the processing is started, the actual effect and the theoretical difference are compared through detection, and the related parameters are adjusted again, so that a closed loop is formed in the whole debugging process.

[0037] 3) According to the light spot shape obtained by step 2), the laser parameters and the galvanometer scanning parameters of the ultrafast laser processing system are set, and the processing of the approximate target groove type is completed; considering that the laser parameters of the ultrafast laser affect the micro groove inner wall angle when debugging, the processing track overlap rate affects the micro groove inner wall angle and the micro groove depth, the laser frequency and the single pulse energy affect the micro groove depth and the micro groove bottom appearance, and the laser scanning speed also affects the micro groove depth and the roughness. Therefore, the application carries out corresponding debugging according to different target grooves and completes the processing of the approximate target groove type. Specifically:

[0038] When the target groove is a rectangular groove, the specific implementation mode of step 3) is:

[0039] a.1) The groove depth and length are controlled by controlling the power of the ultrafast laser;

[0040] a.2) Set the machining track of the rectangular groove, determine the spot energy distribution and spot length through the beam modulation module of the ultrafast laser machining system, adjust the groove width and inner wall angle through the beam modulation module, and optimize the micro groove roughness through the beam modulation module, and finally process the target groove type of the approximate rectangular groove. The machining track of the rectangular groove is a single straight line reciprocating motion. For example, the specific implementation of optimizing the groove roughness through the beam modulation module is to adjust the power of the ultrafast laser through the beam modulation module to optimize the smoothness of the energy step.

[0041] When the target groove is a crescent groove, the specific implementation of step 3) is:

[0042] b.1) Process the micro groove by setting different focal point positions, detect the inner wall angle of the micro groove, and preliminarily determine the machining focal point; wherein the machining focal point is the Z-axis coordinate corresponding to the minimum focal spot; after determining the focal point, the Z-axis is always kept at this position and does not move, otherwise the target groove type cannot be processed. For example, when finding the focal point, set the initial system Z-axis coordinate as a, process a product every 0.1 mm within the range of a±1 mm, and finally determine the desired focal point by detecting the size and inner wall angle of the actual processed product through the 3D profiler.

[0043] b.2) Adjust the ultrafast laser fundamental frequency and power based on the machining focal point obtained in step b.1);

[0044] b.3) Based on the ultrafast laser fundamental frequency and power obtained in step b.2), set the machining track, process the micro groove, measure the actual inner wall angle of the micro groove, and adjust the overlap rate according to the inner wall angle; wherein, see Figure 5 The machining track is formed by gradually moving from the outside of the crescent groove to the inside in a spiral manner.

[0045] b.4) Based on the results obtained in step b.3), set the machining speed, measure the micro groove roughness, and continuously optimize the laser parameters and galvanometer scanning parameters of the ultrafast laser machining system, and finally process the target groove type of the approximate crescent groove.

[0046] 4) Use a 3D profiler to detect the approximate target groove type obtained in step 3) to obtain a detection result, and repeatedly execute steps 2) and 3) according to the difference between the detection result and the actual target groove type, and finally complete the processing of the special-shaped light guiding microstructure.

Claims

1. A method for fabricating an irregularly shaped light-guiding microstructure, characterized in that: The fabrication method of the irregularly shaped light guide microstructure includes the following steps: 1) Obtain the target groove shape of the irregular light guide microstructure and determine the required spot shape of the target groove shape; the target groove is a crescent groove or a rectangular groove; when the target groove is a crescent groove, the specific implementation method for determining the required spot shape of the target groove shape is: using a Gaussian spot, improving the roundness of the spot and optimizing the beam energy distribution state to obtain the required spot shape; when the target groove is a rectangular groove, the specific implementation method for determining the required spot shape of the target groove shape is: shaping the spot into an asymmetrical distribution of the spot energy curve to obtain the required spot shape; 2) Based on the ultrafast laser processing system, the spot shape that conforms to the determination in step 1) is modulated. Specifically, the beam phase is shaped using the beam modulation module of the ultrafast laser processing system, the spot shape is detected by the beam quality analyzer of the spot shape auxiliary detection module, and an online closed-loop test is performed to finally modulate the spot shape that conforms to the determination in step 1). 3) Based on the light spot shape obtained in step 2), set the laser parameters and galvanometer scanning parameters of the ultrafast laser processing system to complete the processing of the approximate target groove shape; When the target slot is a rectangular slot, the specific implementation of step 3) is as follows: a.1) The depth and length of the groove are controlled by controlling the power of the ultrafast laser; a.2) Set the processing trajectory of the rectangular groove, determine the spot energy distribution and spot length through the beam modulation module of the ultrafast laser processing system, adjust the groove width and inner wall angle through the beam modulation module, and optimize the groove roughness through the beam modulation module to finally process the target groove shape that is approximately rectangular. When the target groove is a crescent groove, the specific implementation method of step 3) is as follows: b.1) By setting different focal positions to process microgrooves, the angle of the inner wall of the microgroove is detected to initially determine the processing focal point; the processing focal point is the Z-axis coordinate corresponding to the smallest focused spot. b.2) Based on the processing focus obtained in step b.1), adjust the ultrafast laser fundamental frequency and power; b.3) Based on the ultrafast laser fundamental frequency and power obtained in step b.2), set the processing trajectory, process the microgroove, measure the inner wall angle of the actual microgroove, and adjust its overlap rate according to the inner wall angle; b.4) Based on the results obtained in step b.3), set the processing speed, measure the roughness of the microgroove, and continuously optimize the laser parameters and galvanometer scanning parameters of the ultrafast laser processing system to finally process and form a target groove shape that approximates a crescent shape. 4) Use a 3D profilometer to detect the approximate target groove processing effect obtained in step 3), obtain the detection result, and repeatedly execute steps 2) and 3) based on the difference between the detection result and the actual target groove until the actual processing effect reaches the target groove, thus completing the processing of the irregular light guide microstructure.

2. The fabrication method of the irregularly shaped light guide microstructure according to claim 1, characterized in that: The ultrafast laser processing system includes a laser, an optical path transmission system, a beam modulation module, a galvanometer scanning system, a spot morphology auxiliary detection module, and an industrial control computer. The spot morphology auxiliary detection module includes a beam quality analyzer. The laser generates ultrafast laser light, which sequentially enters the beam modulation module, the galvanometer scanning system, and the spot morphology auxiliary detection module through the optical path transmission system. The spot morphology auxiliary detection module provides feedback on the beam modulation state to the industrial control computer. The industrial control computer outputs a modulation signal to the beam modulation module based on the real-time feedback beam modulation state to achieve a specific spot state. The industrial control computer controls the galvanometer scanning system to complete the processing of the target groove shape.

3. The fabrication method of the irregularly shaped light guide microstructure according to claim 2, characterized in that: The specific implementation method of optimizing the groove roughness through the beam modulation module is as follows: the power of the ultrafast laser is adjusted by the beam modulation module to optimize the smoothness of the energy step.

4. The fabrication method of the irregularly shaped light guide microstructure according to claim 3, characterized in that: The processing trajectory in step b.3) is formed by gradually moving from the outside of the crescent groove in a spiral manner towards the inside.

5. The method for fabricating irregularly shaped light-guiding microstructures according to claim 4, characterized in that: When the target groove is a rectangular groove, the machining trajectory of the rectangular groove in step b.2) is formed by a single linear reciprocating motion.

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