Shaping of brittle materials with controlled surface and bulk properties
View Patent ↗Methods of and devices for forming edge chamfers and through holes and slots on a material that is machined using a laser, such as an ultrafast laser. The shaped material has predetermined and highly controllable geometric shape and/or surface morphology. Further, a method of and a device for preventing re-deposition of the particles on a material that is machined using a laser, such as an ultrafast laser. A fluid is used to wash off the particles generated during the laser machining process. The fluid can be in a non-neutral condition, with one or more chemical salts added, or a condition allowing the coagulation of the particles in the fluid, such that the particles can be precipitated to avoid the reattachment to the machined substrate.
1. A method of laser processing a stock of brittle material, the stock of brittle material having a front surface and an opposite back surface, the method comprising:
placing the stock of brittle material in a manner so that the back surface thereof is in fluid contact with a liquid solution held in a reservoir, the liquid solution having a zeta potential of less than about 10 mV;
applying an ultrafast laser beam to the stock of brittle material, the ultrafast laser beam comprising one of femtosecond or picosecond laser pulses, the ultrafast laser beam incident on the front surface of the stock of brittle material, the ultrafast laser beam having a focus, the focus located on the back surface of the stock of brittle material; and
translating the focus of the ultrafast laser beam from the back surface of the stock of brittle material towards the front surface of the stock of brittle material, the focused ultrafast laser beam removing material from the stock of brittle material by ablation, the material removed by ablation being in the form of debris particles, the liquid solution coagulating the debris particles in the liquid solution, the liquid solution thereby preventing the material removed by ablation from reattaching to the stock of brittle material.
2. The method of claim 1 , wherein the liquid solution includes a salt.
3. The method of claim 2 , wherein the salt is any one of CaCl 2 , MgCl 2 , and NaCl, or a combination thereof.
4. The method of claim 2 , wherein the salt is a divalent salt.
5. The method of claim 1 , wherein the liquid solution has a non-neutral pH value.
6. The method of claim 1 , wherein the liquid solution has a pH value lower than 5.
7. The method of claim 1 , wherein the debris particles removed by ablation are one of nanoparticles and microparticles, or a combination thereof.
8. The method of claim 1 , wherein the material removed by ablation is colloidal silica.
9. The method of claim 1 , further comprising scanning the ultrafast laser beam along a tool path while repeating the applying and translating steps.
10. The method of claim 1 , wherein the ultrafast laser beam comprises picosecond laser pulses.
11. The method of claim 1 , wherein the ultrafast laser beam comprises femtosecond laser pulses.
12. The method of claim 1 , wherein the laser processing forms a through hole or slot in the stock of brittle material.
13. The method of claim 12 , wherein the through hole or slot has a chamfer.
14. The method of claim 12 , wherein the through hole or slot has edges that are round in shape, the round shape having a radius of curvature.
15. The method of claim 1 , wherein the stock of brittle material comprises a multiple layered structure of brittle material.
16. The method of the claim 15 , wherein the focused ultrafast laser beam is applied to one layer of the multiple layered structure of brittle material.
17. The method of claim 1 , wherein the stock of brittle material is made of glass.
18. The method of claim 1 , wherein the stock of brittle material is made of a consumer electronic protective glass.
19. The method of claim 1 , wherein the stock of brittle material is made of sapphire.