Method for making a microstructure in a glass or plastic substrate according to hot-forming technology and associated forming tool

• US 20020035854A1
• Filed: 07/10/2001
• Published: 03/28/2002
• Est. Priority Date: 07/15/2000
• Status: Active Grant

• Current Assignee: SCHOTT Glass
• Original Assignee: SCHOTT Glass
• Inventors: Postrach, Stefan, Thiel, Steffen, Herzbach, Lars Christian
• Granted Patent: US 6,799,438 B2
• Time in Patent Office: Days
• US Class Current: 65/81
• CPC Class Codes: B29C 2059/023 Microembossing
• CPC Class Codes: B29C 2791/006 Using vacuum
• CPC Class Codes: B29C 59/02 by mechanical means, e.g. pressing B29C59/007 takes precedence; embossing expanded porous articles B29C44/5627
• CPC Class Codes: C03B 11/08 for making solid articles, e.g. lenses
• CPC Class Codes: C03B 11/082 having profiled, patterned or microstructured surfaces
• CPC Class Codes: C03B 13/14 Rolling other articles , i.e. not covered by C03B13/01 - C03B13/12, e.g. channeled articles, briquette-shaped articles
• CPC Class Codes: C03B 13/16 Construction of the glass rollers
• CPC Class Codes: C03B 2215/413 optical fibre alignment, fixing or connecting members having V-grooves
• CPC Class Codes: C03B 23/0352 by suction or blowing out for providing the deformation force to bend the glass sheet
• CPC Class Codes: C03B 9/00 Blowing glass; Production of hollow glass articles

Abstract

A microstructure is formed in a viscous glass or plastic substrate by pressing a structured surface of a forming tool corresponding to a negative of the microstructure to be produced in the viscous glass or plastic substrate. After the microstructure has been formed, the forming tool is removed from the surface. In order to help form the microstructure and remove the forming tool from the substrate the forming tool has an at least partially porous base body (1) and an operative layer (2) structured with a negative structure consisting of grooves (11) extending to the porous base body (1). The forming of the microstructure in the substrate is assisted by applying suction to the porous base body (1) so that the grooves (11) fill more easily and completely with melted glass or plastic material. The removal of the forming tool after forming the microstructure is assisted by applying an overpressure to the porous body to help release the solidified glass or plastic material from the forming tool.

Claims

1. A method of making a microstructure in a glass or plastic surface by hot-forming technology, said method comprising the steps of:

a) providing a forming tool comprising a base body (1), said base body (1) comprising an at least partially porous base material with an open pore structure;

b) structuring a surface of a forming tool according to a negative of the microstructure to be produced in the substrate;

c) pressing the forming tool surface structured during the structuring of step b) into a viscous glass or plastic substrate;

d) during the pressing of step c), generating an under pressure that acts on the open pore structure of the base body (1) in order to draw glass or plastic material to the forming tool surface and thus help form the microstructure;

e) after the microstructure has been formed in the substrate in steps c) and d), removing the forming tool from the viscous glass or plastic substrate; and

f) during the removing of step e), generating an overpressure that acts on the open pore structure of the base body to assist in the removing.

2. The method as defined in claim 1, further comprising melting glass or plastic material to form a melt and taking the viscous glass or plastic substrate from the melt.

3. The method as defined in claim 1, further comprising providing a solid glass or plastic substrate, heating the forming tool locally immediately prior to the formation of the microstructure and applying the forming tool heated during the heating to the solid glass or plastic substrate in a region to be structured to plasticize the substrate material and form the viscous glass or plastic substrate.

4. A forming tool for making a microstructure in a glass or plastic surface by hot-forming technology, said forming tool comprising a base body (1), an operative layer (2) applied to a surface on one side of the base body and means (4,5) for supplying or withdrawing air from another surface on another side of the base body (1) opposite from the one side on which the operative layer (2) is applied,

wherein said base body (1) comprises a porous base material with an open pore structure and said operative layer (2) comprises a gas-impermeable material structured according to a negative of the microstructure to be produced by the forming tool in order to form depressions or grooves (11) that extend through the operative layer (2) to the base material with the open pore structure.

5. The forming tool as defined in claim 4, wherein said base body (1) consists entirely of said porous base material with the open pore structure.

6. The forming tool as defined in claim 5, wherein said base body (1) has gas-impermeable side walls (15).

7. The forming tool as defined in claim 4, wherein only a portion (1b) of said base body (1) next to said operative layer (2) consists of said porous base material with the open pore structure, while a remaining portion (1a) of the base body (1) is gas-impermeable.

8. The forming tool as defined in claim 7, wherein said portion (1b) of the base body (1) next to said operative layer (2) has gas-impermeable side walls (15).

9. The forming tool as defined in claim 4, consisting of a pressing roller or a press tool.