Edge chamfering by mechanically processing laser cut glass
Processes of chamfering and/or beveling an edge of a glass substrate of arbitrary shape using lasers are described herein. Two general methods to produce chamfers on glass substrates are the first method involves cutting the edge with the desired chamfer shape utilizing an ultra-short pulse laser that is followed by mechanical polishing with a compliant polishing wheel.
1. A method of chamfering or beveling an edge of a workpiece comprising a glass substrate, the method comprising the steps of:
(i) focusing a pulsed laser beam into a laser beam focal line, viewed along a beam propagation direction;
(ii) directing the laser beam focal line into the workpiece at a first angle of incidence to the workpiece, the first angle intersecting an edge of the workpiece, the laser beam focal line generating an induced absorption within the workpiece, the induced absorption producing a defect line along the laser beam focal line within the workpiece;
(iii) translating the workpiece and the laser beam relative to each other, thereby forming a plurality of defect lines along a first plane at the first angle within the workpiece, each of said defect lines having a diameter of not greater than 5 μm; and
(iv) separating the workpiece along the plane to create a laser cut workpiece with at least one laser cut surface; and
(v) processing the workpiece by polishing the laser cut surface of the laser cut workpiece with a polishing wheel, wherein the polishing wheel has a bulk modulus of elasticity of 0.1 GPa to 5 GPa, said abrasive particles having relative toughness of at least 600 MBG.
2. A method according to claim 1 , further comprising:
directing the laser beam focal line into the workpiece at a second angle of incidence to the workpiece, the laser beam focal line generating an induced absorption within the workpiece, the induced absorption producing a defect line along the laser beam focal line within the workpiece;
translating the workpiece and the laser beam relative to each other, thereby forming a second plurality of defect lines along a second plane at the second angle within the workpiece, the second plane intersecting the first plane, each of said second plurality of defect lines having a diameter of not greater than 5 μm, and
wherein said separating is performed by separating the material along the first plane and the second plane, producing said laser cut workpiece.
3. A method of chamfering or beveling an edge of a workpiece according to claim 1 by laser processing a glass material, the method comprising:
inducing a plurality of defect lines along each of N planes within the material by, for each of the N planes by:
directing the laser beam focal line into the material at a corresponding angle of incidence to the material, the laser beam focal line generating an induced absorption within the material, the induced absorption producing a defect line along the laser beam focal line within the material; and
translating the material and the laser beam relative to each other, thereby laser forming the plurality of defect lines along the corresponding plane of the N planes, each of said plurality of defect lines having a diameter of not greater than 5 μm; and
separating the workpiece along at least one of said N planes by applying an ion-exchange process to the workpiece to create a laser cut workpiece with the laser cut surface; and
wherein said step of polishing said laser cut surface of said laser cut workpiece by said polishing wheel having a bulk modulus of elasticity of 0.1 GPa to 5 GPa for a time t, where 1 sec<t<1 min, wherein the polishing wheel comprises abrasive particles.
4. The method of claim 1 , wherein said polishing wheel has an outer diameter of 40 mm to 250 mm.
5. The method of claim 4 , wherein said polishing wheel has an outer diameter of 50 mm to 200 mm.
6. The method of claim 5 , wherein said polishing wheel has an outer diameter of 80 mm to 120 mm.
7. The method according to claim 1 , wherein the polishing wheel is rotated at 500 rpm to 10000 rpm.
8. The method according to claim 7 , wherein the polishing wheel is rotated at 500 rpm to 8000 rpm.
9. The method according to claim 1 , wherein the polishing wheel comprises of multiple abrasive particles, said abrasive particles having a cross-sectional width of 0.1 μm to 100 μm.
10. The method according to claim 1 , wherein the polishing wheel comprises multiple abrasive particles, said abrasive particles having relative toughness of 600 MBG to 680 MBG.
11. The method according to claim 1 , wherein said laser beam is produced by a burst pulse laser with the pulse duration in a range of between greater than about 5 picoseconds and less than about 20 picoseconds, the burst repetition rate in a range of between about 1 kHz and 2 MHz.
12. The method according to claim 11 , wherein the burst repetition rate is in a range of between about 10 kHz and 650 kHz.
13. The method according to claim 11 , wherein said burst pulse laser produces burst pulses that include 2-25 pulses per burst.
14. The method according to claim 1 , wherein said laser has power 8 Watts or higher.
15. The method according to claim 1 , wherein said laser has 10-100 Watts of power.
16. The method according to claim 1 , wherein said laser has power that is between 40 microJoules per mm thickness of workpiece material and 1000 microJoules per mm thickness of workpiece material.
17. The method according to claim 1 , wherein said laser beam focal line has an average spot diameter in a range of between about 0.1 μm and about 5 μm and length between 0.5 mm and 1.5 mm.