Optical tool assembly for improved RCW and lens edge formation

• US 20060145372A1
• Filed: 12/30/2004
• Published: 07/06/2006
• Est. Priority Date: 12/30/2004
• Status: Abandoned Application

• Current Assignee: Bausch & Lomb Incorporated (Bausch Health Cos., Inc.)
• Original Assignee: Bausch & Lomb Incorporated (Bausch Health Cos., Inc.)
• Inventors: Jones, Thomas G., Lawton, Bruce E.
• Application Number:
  US11/027,406
• Publication Number:
  US 20060145372A1
• Time in Patent Office: Days
• US Class Current: 264/1.320
• CPC Class Codes: B29C 45/2673 with exchangeable mould parts, e.g. cassette moulds B29C45/1756 takes precedence
• CPC Class Codes: B29C 45/2675 Mounting of exchangeable mould inserts
• CPC Class Codes: B29D 11/00038 Production of contact lenses
• CPC Class Codes: B29D 11/00125 Auxiliary operations, e.g. removing oxygen from the mould, conveying moulds from a storage to the production line in an inert atmosphere
• CPC Class Codes: B29D 11/0048 Moulds for lenses moulds for plastic articles in general B29C33/00
• CPC Class Codes: B29L 2011/0041 Contact lenses

Abstract

An optical tool assembly for use in an injection molding apparatus opposite a non-optical tool assembly to form an ophthalmic mold section including a cavity ring mounted to an associated mold plate and an optical insert removeably secured to the cavity ring and having an optical molding surface thereon for forming an optical surface of the ophthalmic mold section. The optical molding surface has a right cylindrical wall (RCW) molding portion for forming a RCW of the ophthalmic mold section. The RCW molding portion is formed adjacent a peripheral edge of the optical insert.

Claims

1. An optical tool assembly for use in an injection molding apparatus opposite a non-optical tool assembly to form an ophthalmic mold section, comprising:

a cavity ring mounted to an associated mold plate; and

an optical insert removably secured to said cavity ring and having an optical molding surface thereon for forming an optical surface of the ophthalmic mold section, said optical molding surface having a right cylindrical wall molding portion for forming a right cylindrical wall of the ophthalmic mold section, said right cylindrical wall molding portion formed adjacent a peripheral edge of said optical insert.

2. The optical tool assembly of claim 1 wherein said right cylindrical wall molding portion is generally parallel to a mold cavity axis.

3. The optical tool assembly of claim 1 wherein said optical molding surface includes a curved junction portion transitioning said right cylindrical wall molding portion to a remainder of said optical molding surface.

4. The optical tool assembly of claim 1 wherein said cavity ring includes a cavity ring molding surface that forms a mold section portion of the ophthalmic mold section surrounding said optical surface.

5. The optical tool assembly of claim 4 wherein said mold section portion includes at least one of said segment wall outer surface and said cylindrical wall outer surface.

6. The optical tool assembly of claim 4 wherein said right cylindrical wall molding portion terminates into said cavity ring molding surface.

7. The optical tool assembly of claim 4 wherein a parting line interface is formed between a head of said optical insert and said cavity ring molding surface, said parting line interface oriented approximately normal relative to molding cavity axis.

8. The optical tool assembly of claim 1 wherein said right cylindrical wall molding portion is oriented approximately normal relative to said cavity ring molding surface which flanks said right cylindrical wall molding surface.

9. The optical tool assembly of claim 1 wherein substantially no gap is formed between said right cylindrical wall molding portion and a molding surface of said cavity ring that forms an outer segment surface of the ophthalmic mold section.

10. The optical tool assembly of claim 1 wherein said optical tool insert is received within a recess defined in said cavity ring, a surface defining said recess forms an optical tool assembly molding surface for forming outer surfaces of said ophthalmic lens mold, and a head portion of said optical tool insert protrudes into said recess and includes said optical molding surface thereon.

11. The optical tool assembly of claim 10 wherein said right cylindrical wall molding portion is disposed on said head portion adjacent a peripheral edge of said head portion.

12. The optical tool assembly of claim 11 wherein said head portion includes a shoulder that abuts said optical tool assembly molding surface.

13. An apparatus for injection molding an ophthalmic lens mold having an optical surface and a non-optical surface opposite the optical surface, comprising:

a non-optical tool assembly for forming the non-optical surface of the ophthalmic lens mold;

an optical tool assembly in opposed relation to said non-optical tool assembly that together therewith forms a mold cavity for forming the ophthalmic lens mold, said optical tool assembly includes;

a cavity ring removably secured to a mold plate of an injection molding apparatus, said cavity ring having a cavity ring molding surface;

an optical tool insert having an optical molding surface thereon for forming the optical surface of the ophthalmic lens mold, the optical tool insert removably secured to said cavity ring; and

a right cylindrical wall molding portion of said optical molding surface formed adjacent a peripheral edge of said optical molding surface, said right cylindrical wall molding portion extending substantially perpendicular to said cavity ring molding surface.

14. The apparatus at claim 13 wherein said cavity ring molding surface forms a segment wall of the ophthalmic lens mold.

15. The apparatus of claim 13 wherein a parting line interface is formed between said optical tool insert and said cavity ring that is oriented substantially perpendicular relative to the direction of draw when removing said ophthalmic lens mold from said non-optical tool assembly.

16. The apparatus of claim 13 wherein said right cylindrical wall molding portion is formed adjacent a peripheral edge of said optical insert.

17. The apparatus of claim 13 wherein said non-optical tool assembly includes:

a core member having a cooling cavity with a cooling medium therein for cooling the ophthalmic lens mold after injection molding, said core member removably secured to a second mold plate of said injection molding apparatus;

a non-optical insert removably secured to said core member at a location spaced from said cooling cavity, said non-optical insert having a first molding surface for forming a surface of the ophthalmic lens mold opposite the optical surface; and

a stripper member annularly disposed on said core member and positioned to forcibly remove the ophthalmic lens mold from said non-optical insert after injection molding thereof upon advancement of said stripper member.

18. The apparatus of claim 17 wherein said cavity ring and said stripper member define a runner fluidly connected to said mold cavity for allowing molten resin to be injected into said mold cavity when injection molding the ophthalmic lens mold.

19. An injection molding apparatus for forming a mold section which is subsequently used for forming an ophthalmic lens, comprising:

a mold member mounted to an associated first mold plate;

an optical tool insert removably mounted to said mold member, said optical tool insert having a molding surface with an optical quality finish that includes a right cylindrical wall forming a peripheral edge of said optical tool insert;

a core member mounted to an associated second mold plate opposite the associated first mold plate; and

a non-optical tool insert removably mounted to said core member, said non-optical insert having a non-optical molding surface for forming a surface of the mold section opposite the optical surface.

20. The injection molding apparatus of claim 19 wherein said mold member, said optical insert and said non-optical insert together form a mold cavity shaped to mold the mold section.

21. A method for forming an ophthalmic lens, comprising the steps of:

providing an apparatus for injection molding an ophthalmic lens mold having an optical surface and a non-optical surface opposite the optical surface, wherein the apparatus comprises;

a) a non-optical tool assembly for forming the non-optical surface of the ophthalmic lens mold and an optical tool assembly in opposed relation to the non-optical tool assembly that together therewith forms a mold cavity for forming the ophthalmic lens mold;

b) the optical tool assembly including a cavity ring removably secured to a mold plate, said cavity ring having a cavity ring molding surface;

c) an optical tool insert having an optical molding surface thereon for forming the optical surface of the ophthalmic lens mold, the optical tool insert removably secured to the cavity ring; and

d) a right cylindrical wall molding portion of the optical molding surface formed adjacent a peripheral edge of the optical molding surface, the right cylindrical wall molding portion extending substantially perpendicular to said cavity ring molding surface;

wherein said method comprises the steps of;

a) injection molding the ophthalmic mold section in the mold cavity;

b) removing the molded ophthalmic mold from the mold cavity;

c) matching the ophthalmic mold section with a mating ophthalmic mold section; and

d) cast molding an ophthalmic lens between the ophthalmic mold sections.

22. An ophthalmic lens formed according to the method of claim 21.