Structure and method for molding optical disks

• US 6,533,968 B1
• Filed: 09/05/2000
• Issued: 03/18/2003
• Est. Priority Date: 05/01/1998
• Status: Expired due to Fees

• Current Assignee: Sabic Innovative Plastics IP BV (Government of Saudi Arabia)
• Original Assignee: General Electric Company
• Inventors: Gorczyca, Thomas Bert, Feist, Thomas Paul
• Primary Examiner(s): Vargot, Mathieu D.
• Application Number:
  US09/655,322
• Time in Patent Office: 924 Days
• Field of Search: 264/1.33, 264/1.1, 264/2.1, 264/299, 264/310, 264/81, 264/219, 264/334, 264/338
• US Class Current: 264/1.33
• CPC Class Codes: B29C 2045/2636 insulating layers
• CPC Class Codes: B29C 45/2632 Stampers; Mountings thereof
• CPC Class Codes: B29C 45/2642 Heating or cooling means therefor
• CPC Class Codes: Y10S 425/81 Sound record

Abstract

A method for molding an optical disk comprises: applying a thermally insulative insert coating to at least one thermally insulative mold insert to provide at least one coated mold insert having a reduced surface roughness; positioning the coated mold insert between a thermally conductive mold form and a portion of a thermally conductive mold apparatus; injecting a molten thermoplastic material into the mold apparatus; retaining the material in the mold apparatus for a time sufficient for the molten thermoplastic material to cool below its glass transition temperature to form the optical disk; and ejecting the optical disk from the mold apparatus. In another embodiment, the mold insert is coated or laminated on the mold form with the mold insert having a coefficient of thermal expansion compatible with the coefficient of thermal expansion of the mold form. In another embodiment, the mold insert is fabricated by being applied, cured, and then removed from a release layer.

Claims

1. A method for fabricating a mold insert for use in molding an optical disk comprising:

providing a substrate having a release layer coated thereon;

coating a solution of liquid insulative mold insert material on the release layer;

curing the mold insert material to form the mold insert and

removing the mold insert from the release layer and the substrate.

2. The method of claim 1 wherein removing the mold insert from the release layer and the substrate comprises peeling the mold insert from the release layer and the substrate.

3. The method of claim 1 wherein removing the mold insert from the release layer and the substrate comprises immersing the substrate and the mold insert in a liquid.

4. The method of claim 1 wherein the release layer is titanium nitride or gold.

5. The method of claim 4 further comprising applying the release layer on the substrate using an evaporation process.

6. The method of claim 4 further comprising applying the release layer on the substrate using a sputtering process.

7. A method for fabricating a mold insert comprising:

applying a release layer to a smooth substrate, the release layer having a lower surface energy than the substrate;

spin coating a solution of liquid mold insert material on the release layer;

curing the mold insert material to form the mold insert; and

removing the mold insert from the release layer and the substrate.

8. The method of claim 7 wherein the substrate comprises glass or silicon, wherein the release layer comprises titanium nitride or gold, and wherein the insert material comprises a polymer.

9. The method of claim 7 wherein removing the insert from the release layer and the substrate comprises immersing the substrate and the insert in a liquid.

10. A method for molding an optical disk comprising:

fabricating a mold insert by;

providing a substrate having a release layer coated thereon,

coating a solution of liquid insulative mold insert material on the release layer,

curing the mold insert material to form the mold insert, and

removing the mold insert from the release layer and the substrate;

positioning the mold insert between a thermally conductive mold form and a portion of a thermally conductive mold apparatus;

injecting a molten thermoplastic material into the mold apparatus;

retaining the molten thermoplastic in the mold apparatus for a time sufficient for the molten thermoplastic material to cool below its glass transition temperature to form the optical disk; and

ejecting the optical disk from the mold apparatus.

11. The method of claim 10 wherein the substrate comprises glass or silicon, wherein the release layer comprises titanium nitride or gold, and wherein the insert material comprises a polymer.

12. The method of claim 10 wherein removing the insert from the release layer and the substrate comprises immersing the substrate and the insert in a liquid.

13. The method of claim 10 further comprising applying the release layer on the substrate using an evaporation process.

14. The method of claim 10 further comprising applying the release layer on me substrate using a sputtering process.