Silicon rubber surfaces for biometric print TIR prisms

• US 20030016427A1
• Filed: 04/26/2002
• Published: 01/23/2003
• Est. Priority Date: 04/26/2001
• Status: Abandoned Application

• Current Assignee: Cross Match Technologies Incorporated (Assa Abloy AB)
• Original Assignee: Cross Match Technologies Incorporated (Assa Abloy AB)
• Inventors: Arnold, Joe F., Bardons, Charles P.
• Application Number:
  US10/132,719
• Publication Number:
  US 20030016427A1
• Time in Patent Office: Days
• US Class Current: 359/222
• CPC Class Codes: B29C 37/006 Degassing moulding material or draining off gas during moulding venting means in moulds B29C33/10
• CPC Class Codes: B29C 37/0078 Measures or configurations for obtaining anchoring effects in the contact areas between layers surface shaping B29C59/00; B29C66/02 takes precedence
• CPC Class Codes: B29C 39/02 for making articles of definite length, i.e. discrete articles
• CPC Class Codes: B29C 39/10 incorporating preformed parts or layers, e.g. casting around inserts or for coating articles coating a surface by casting in general B05D1/30, B29C39/126 takes precedence
• CPC Class Codes: B29K 2083/005 LSR, i.e. liquid silicone rubbers, or derivatives thereof
• CPC Class Codes: B32B 17/063 of rubber
• CPC Class Codes: B32B 17/10 of synthetic resin
• CPC Class Codes: B32B 2038/0076 Curing, vulcanising, cross-linking
• CPC Class Codes: B32B 2255/10 on synthetic resin layer or on natural or synthetic rubber layer
• CPC Class Codes: B32B 2319/00 Synthetic rubber
• CPC Class Codes: B32B 2323/04 Polyethylene
• CPC Class Codes: B32B 2327/18 PTFE, i.e. polytetrafluoroethylene
• CPC Class Codes: B32B 2369/00 Polycarbonates
• CPC Class Codes: B32B 25/04 comprising rubber as the main or only constituent of a layer, which is next to another layer of the same or of a different material next to a layer of a particular substance B32B9/043; next to a bituminous or tarry layer B32B11/044; next to a water setting substance layer B32B13/042; next to a metal layer B32B15/06; next to a glass layer B32B17/063; next to a layer formed of natural mineral fibres or particles B32B19/043; next to a wood layer B32B21/045; next to a cellulosic plastic layer B32B23/046
• CPC Class Codes: B32B 25/08 of synthetic resin
• CPC Class Codes: B32B 25/20 comprising silicone rubber
• CPC Class Codes: B32B 27/308 comprising acrylic (co)polymers
• CPC Class Codes: B32B 27/322 comprising halogenated polyolefins, e.g. PTFE
• CPC Class Codes: B32B 27/365 comprising polycarbonates
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: G02B 1/10 : Optical coatings produced by application to, or surface treatment of, optical elements G02B1/08 takes precedence
• CPC Class Codes: G02B 5/04 : Prisms
• CPC Class Codes: G02B 7/18 : for prisms; for mirrors
• CPC Class Codes: G06V 40/1324 : by using geometrical optics, e.g. using prisms G06V40/1312 takes precedence
• CPC Class Codes: Y10T 428/31598 : Next to silicon-containing [silicone, cement, etc.] layer

Abstract

Molded silicone rubber sheets with optical quality surfaces and methods for making the same. The silicone rubber sheets are made by molding liquid silicone rubber in a mold. In embodiments, the mold forms parallel optical quality flat surfaces. In one embodiment, a stiffening plastic is molded in the middle of the silicone rubber sheet between the parallel optical quality flat surfaces. In another embodiment, the mold forms one optical quality flat surface while the surface parallel to the optical quality flat surface is bonded to a prism.

Claims

1. A silicone rubber sheet, comprising:

at least one layer of silicone rubber compound; and

at least one optical quality surface attached to said at least one silicone rubber compound, wherein said at least one optical quality surface is molded to said at least one layer of silicone rubber compound.

2. The silicone rubber sheet of claim 1, wherein said at least one layer of silicone rubber compound is comprised of one of liquid silicone and liquid silicone diluted with a silicone thinner.

3. The silicone rubber sheet of claim 1, wherein said at least one layer of silicone rubber compound is integrally molded to a surface of a device.

4. The silicone rubber sheet of claim 3, wherein said device is a TIR (Total Internal Reflection) prism.

5. The silicone rubber sheet of claim 2, wherein said silicone rubber compound comprised of liquid silicone diluted with a silicone thinner is diluted 10-40 percent.

6. The silicone rubber sheet of claim 1, wherein said at least one layer silicone rubber compound includes a TIR platen surface that is of optical quality.

7. The silicone rubber sheet of claim 1, wherein said at least one layer of silicone rubber compound has an embedded layer of a stiff plastic approximately midway of said at least one layer of silicone rubber compound.

8. A method for making a silicone rubber sheet, comprising the steps of:

(1) preparing a liquid silicone compound;

(2) out gassing said liquid silicone compound;

(3) pouring said liquid silicone compound into one or more cavity molds; and

(4) curing said liquid silicone compound to generate said silicone rubber sheet.

9. The method of claim 8, further comprising the step of removing said silicone rubber sheet from said mold.

10. The method of claim 9, further comprising the step of cutting said silicone rubber sheet to defined dimensions for a defined application.

11. The method of claim 8, wherein step (1) comprises the steps of:

(a) coating a surface of a prism with a binder; and

(b) curing the binder, wherein said silicone rubber sheet will be integrally molded to the prism after step (4) is completed.

12. The method of claim 11, wherein step (a) further comprises the step of coating said binder with a silicone sealer.

13. The method of claim 8, wherein step (1) comprises the steps of:

(a) applying a binder to a stiffening material;

(b) curing said stiffening material;

(c) placing said stiffening material in a tension device between said one or more cavity molds; and

(d) tensioning said stiffening material.

14. The method of claim 8, wherein step (1) comprises the step of diluting liquid silicone with a silicone thinner solution.

16. The TIR platen of claim 15, wherein said silicone rubber compound is integrally molded to said prism.

17. The TIR platen of claim 15, wherein said silicone rubber compound includes a stiff plastic material in the middle of said silicone rubber compound.

15. A total internal reflective (TIR) platen for a biometric imaging device, comprising:

a silicone rubber compound; and

a first and second optical quality molded surface, wherein said first optical quality molded surface provides for a TIR platen surface and said second optical quality molded surface for making optical contact with a prism.