Device and method for machining transparent medium by laser

• US 6,130,401 A
• Filed: 07/22/1999
• Issued: 10/10/2000
• Est. Priority Date: 07/29/1998
• Status: Expired due to Fees

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Jang, Jun Ho, Yoo, Tae Kyung
• Primary Examiner(s): MILLS, GREGORY L
• Application Number:
  US09/358,768
• Time in Patent Office: 446 Days
• Field of Search: 219/121.6, 219/121.67, 219/121.68, 219/121.69, 219/121.72, 219/121.85, 219/121.82, 219/121.78, 219/121.66, 156/272.8, 264/400
• US Class Current: 219/121.6
• CPC Class Codes: B23K 26/082 Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
• CPC Class Codes: B23K 26/18 using absorbing layers on the workpiece, e.g. for marking or protecting purposes
• CPC Class Codes: B23K 26/364 for making a groove or trench, e.g. for scribing a break initiation groove
• CPC Class Codes: C03B 33/091 using at least one focussed radiation beam, e.g. laser beam C03B33/0955 takes precedence
• CPC Class Codes: C03C 23/002 by ultraviolet light
• CPC Class Codes: Y02P 40/57 Improving the yield, e-g- reduction of reject rates

Abstract

Transparent media having high hardness and poor light absorption is cut or scribed with characters or figures by a laser beam. The method includes forming a support of a medium which is a good absorber of a laser beam, and placing the transparent medium on the support, and focusing the laser beam onto the support through the transparent medium while the transparent medium and the laser beam are moved relative to each other. A flame is generated between the support and the transparent medium to machine the transport medium, allowing it to be cut or scribed with characters or figures.

Claims

1. A method for machining a transparent medium with a laser, comprising:

forming a support of a medium which is a good absorber of a laser beam, the support having a least a first support surface;

placing a transparent medium to be machined over the first support surface, the transparent medium including a first transparent medium surface placed over the first support surface such that the first transparent medium surface faces the first support surface;

focusing the laser beam onto the first support surface through the transparent medium to produce a flame from localized heating of the first support surface;

using the flame to heat and locally melt a portion of the first transparent medium surface corresponding to a region to be machined; and

causing relative movement between the transparent medium placed over the support and the laser beam to machine a desired pattern in the transparent medium.

2. A method as recited in claim 1, wherein the support is moved while the laser beam is fixed to cause the relative movement.

3. A method as recited in claim 1, wherein the laser beam is moved while the support is fixed to cause the relative movement.

4. A method as recited in claim 1, wherein the laser beam forms a groove through the first surface of the transparent medium to cut the transparent medium.

5. A method as recited in claim 1, wherein the laser beam forms a shallow groove in the first surface of the transparent medium followed by application of mechanical stress to the transparent medium to cut the transparent medium.

6. A method as recited in claim 1, wherein the laser beam scribes a character or a figure in the transparent medium.

7. A method as recited in claim 1, further comprising adjusting a thermal impact to a portion of the support at which the laser beam is focused through cooling of a focusing point of the laser.

8. A method as recited in claim 1, wherein the laser beam is emitted from a solid state laser.

9. An apparatus for machining a transparent medium by a laser comprising:

support means for supporting a transparent medium, the support means including a stripe of a material which absorbs the laser beam better than the transparent medium, a roll for winding the stripe, and a roller for guiding the stripe at a position to which a laser beam is focused;

laser beam generating means for providing a laser beam onto the support means through the transparent medium; and

,

moving means for moving either the support means or the laser beam.

10. An apparatus as recited in claim 9 wherein the laser beam generating means includes a solid state laser for providing a laser beam and a lens for focusing the laser beam onto the support means.

11. An apparatus as recited in claim 9, wherein the moving means for moving the laser beam includes a plurality of reflection mirrors disposed in a laser beam path, motors for moving the reflection mirrors, and a controller for controlling the motors.

12. An apparatus as recited in claim 9, wherein the moving means for moving the laser beam includes:

a reflection mirror disposed in a laser beam path;

a lens for focusing the laser beam reflected by the reflection mirror to the support means;

motors for moving the reflection mirror and the lens; and

a controller for controlling the motors.

13. A method for machining a series of thin film devices disposed on a transparent medium using a laser, comprising:

providing a transparent medium having a first transparent medium surface and a second transparent medium surface, the transparent medium having a plurality of thin film devices disposed on the second transparent medium surface, the thin film devices comprising at least one thin film including active device regions and field regions;

removing a portion of the at least one thin film disposed at a field region to expose a portion of the second transparent medium surface creating an exposed region;

forming a support of a medium which is a good absorber of a laser beam, the support having a least a first support surface;

placing the transparent medium having the thin film devices formed thereon over the first support surface, such that the first transparent medium surface faces the first support surface and the thin film devices formed on the second transparent medium surface face away from the first support surface;

focusing the laser beam onto the first support surface through the exposed regions of the transparent medium to produce a flame from localized heating of the first support surface;

using the flame to heat and locally melt a portion of the first transparent medium surface corresponding to a region to be machined; and

causing relative movement between the transparent medium placed over the support and the laser beam to machine a desired pattern in the transparent medium.