Molds for casting silicone rubber contact lenses

• US 3,915,609 A
• Filed: 03/18/1974
• Issued: 10/28/1975
• Est. Priority Date: 03/18/1974
• Status: Expired due to Term

• Current Assignee: CIBA Vision Corporation (Bayer AG)
• Original Assignee: Charles C. Robinson
• Inventors: Robinson, Charles C.
• Primary Examiner(s): Spicer, Jr., Robert L.
• Application Number:
  US05/452,176
• Time in Patent Office: 589 Days
• Field of Search: 425/174.6,174.8E,808,385,412 264/1
• US Class Current: 425/174.6
• CPC Class Codes: B29D 11/00057 characterised by the shape or surface condition of the edge, e.g. flashless, burrless, smooth
• CPC Class Codes: Y10S 425/808 Lens mold

Abstract

A mold for casting contact lenses from an unpolymerized resin such as silicone gum wherein the resin is polymerized by high energy radiation such as an electron beam. One side of the mold is a cap capable of transmitting radiation, which is positioned by a mandrel while the resin is being cast. The mandrel is removed while radiation is applied. Silicone contact lenses cured have substantially greater flexibility at the periphery than at the center may be produced by decreasing the amount of radiation applied to the periphery of the lens.

Claims

1. MOLDING APPARATUS FOR SEQUENTIALLY SHAPING AND CURING A CONTACT LENS OF A SILICONE RESIN WITH A HIGH ENERGY PARTICLE BEAM WHICH COMPRISES:

A. A FIRST MOLD MEMBER HAVING A MOLDING SURFACE, B. A SECOND MOLD HAVING A MOLDING SURFACE DEFINING A MOLD CAVITY IN COOPERATION WITH SAID FIRST MOLD MEMBER, SAID SECOND MOLD MEMBER HAVING A SURFACE EXTERIOR TO SAID MOLD CASTING AND SPACED FROM SAID MOLDING SURFACE THEREOF AND BEING CONSTRUCTED OF A MATERIAL TRANSMITTING THE HIGH ENERGY PARTICLE BEAM, A MATERIAL THICKNESS BETWEEN MOLDING AND EXTERIOR SURFACES BEING SELECTED TO

2. The apparatus of claim 1 wherein said first mold member is a male member and the second mold member is a female member.

3. The apparatus of claim 1 further including means for generating a high energy electron beam.

4. The apparatus of claim 3 wherein said means is a Van de Graaff generator.

5. The apparatus of claim 1 further including a gasket member positioned between said first and second mold members to shape the edge of said contact lens.

6. The apparatus of claim 1 wherein said second mold member is metal.

7. The apparatus of claim 6 wherein the metal is stainless steel, the thickness is about 0.5 to 2.0 mm. and the particle beam has an energy level of about 3.5 MeV.

8. The apparatus of claim 1 wherein the second mold member is fused quartz.

9. The apparatus of claim 8 wherein the thickness is about 1 to 10mm. and the particle beam has an energy level of about 3.5 MeV.

10. The apparatus of claim 1 wherein the second mold member is glass.

11. The apparatus of claim 10 wherein the thickness is about 3mm. and the particle beam has an energy level of about 3.5 MeV.

12. The apparatus of claim 1 wherein the thickness of the second member is greater in one portion than the remainder of said second member.

13. The apparatus of claim 1 wherein the thickness at the peripheral portion of the cavity is greater than the thickness at the center of the lens.