Ir-emitter heating device and method for demolding lenses

Abstract

A method and a device for removing molded soft contact lenses, high-precision intraocular lenses and the like, from the individual molds in which they are produced. Provided is an infra-red radiation or heater device preferably constituted of silicon carbide IR-emitters, and which employs an individual infra-red emitter for each individual mold, to impart a desired thermal gradient. Also provided are infra-red emitters having improved reflectors.

What is claimed is:  
     
         1 . An apparatus for demolding a lens formed between front and back mold halves, said apparatus comprising: 
 means for directing a predetermined amount of infra-red energy at one of said mold halves to thereby provide a controlled thermal gradient between said mold halves.    
     
     
         2 . An apparatus as claimed in  claim 1 , wherein each said infra-red energy means comprises a silicon carbide (SiC) IR-emitter.  
     
     
         3 . An apparatus as claimed in  claim 2 , wherein each said silicon carbide IR-emitters is arranged within a cylindrical sleeve, and a cooling housing collectively encompasses said cylindrical sleeves to inhibit excessive heating of said silicon carbide IR-emitters.  
     
     
         4 . An apparatus as claimed in  claim 3 , wherein reflector means are arranged in each said sleeve extending about head portions of said silicon carbide IR-emitters so as to direct the infra-red energy towards the back curve mold halves for controlled heating thereof.  
     
     
         5 . An apparatus as claimed in  claim 4 , wherein said reflector means comprises a mirror-like reflecting surface for directing said infra-red energy.  
     
     
         6 . An apparatus as claimed in  claim 5 , wherein said reflecting surface possesses a frusto-conical configuration.  
     
     
         7 . An apparatus as claimed in  claim 5 , wherein said reflecting surface forms a parabolic reflector.  
     
     
         8 . An apparatus as claimed in  claim 2 , wherein each said silicon carbide IR-emitter is connected to a source of electrical current to facilitate varying the heat being conveyed to each respective therewith associated back curve mold half so as to impart the required thermal gradient to each said respective back curve mold half.  
     
     
         9 . An apparatus as claimed in  claim 2 , wherein means for sensing the temperatures at each back curve mold half form a feedback of each said temperatures to a preheater for preheating said back curve mold halves to a predetermined temperature prior to said silicon carbide IR-emitter imparting said thermal gradients to each of said back curve mold halves.  
     
     
         10 . An apparatus as claimed in  claim 9 , wherein said curve mold halves are each preheated to a temperature of between about 57-65° C. prior to being subjected to infra-red energy from said silicon carbide IR-emitter.  
     
     
         11 . An apparatus as claimed in  claim 9 , wherein said temperature feedback measures voltage and current for each said silicon carbide IR-emitters, and regulates the voltage and current to provide the required thermal gradient for each said back curve mold half.  
     
     
         12 . An apparatus as claimed in  claim 11 , wherein said voltage and current is regulated by a PID controller.  
     
     
         13 . An apparatus as claimed in  claim 1 , further comprising means for separating each of said associated front and back curve mold halves subsequent to the application of the thermal gradient thereto by said infra-red energy means.  
     
     
         14 . A method of demolding a lens formed between corresponding front and back curve mold halves, said method comprising: 
 separately having a source directing predetermined amounts of infra-red energy at one of said mold halves to thereby provide a controlled thermal gradient between said mold halves.    
     
     
         15 . A method as claimed in  claim 14 , wherein said infra-red energy is provided by silicon carbide (SiC) IR-emitters.  
     
     
         16 . A method as claimed in  claim 15 , wherein each of said silicon carbide IR-emitters is arranged within a cylindrical sleeve, and a cooling housing collectively encompasses said cylindrical sleeves to inhibit excessive heating of said silicon carbide IR-emitters.  
     
     
         17 . A method as claimed in  claim 16 , wherein reflector means are arranged in each said sleeve extending about head portions of said silicon carbide IR-emitters so as to direct the infra-red energy towards the back curve mold halves for controlled heating thereof.  
     
     
         18 . A method as claimed in  claim 17 , wherein said reflector means comprises a mirror-like reflecting surface for directing said infra-red energy.  
     
     
         19 . A method as claimed in  claim 18 , wherein said reflecting surface possesses a frusto-conical configuration.  
     
     
         20 . A method as claimed in  claim 18 , wherein said reflecting surface forms a parabolic reflector.  
     
     
         21 . A method as claimed in  claim 15 , wherein each said silicon carbide IR-emitter is connected to a source of electrical current to facilitate varying the heat being conveyed to each respective therewith associated back curve mold half so as to impart the required thermal gradient to each said respective back curve mold half.  
     
     
         22 . A method as claimed in  claim 15 , wherein sensing the temperatures at each back curve mold half provides a feedback of each said temperatures to a preheater for preheating said back curve mold halves to a predetermined temperature prior to said silicon carbide IR-emitter imparting said thermal gradients to each of said back curve mold halves.  
     
     
         23 . A method as claimed in  claim 22 , wherein said curve mold halves are each preheated to a temperature of between about 57-65° C. prior to being subjected to infra-red energy from said silicon carbide IR-emitter.  
     
     
         24 . A method as claimed in  claim 22 , wherein said temperature feedback measures voltage and current for each said silicon carbide IR-emitters, and regulates the voltage and current to provide the required thermal gradient for each said back curve mold half.  
     
     
         25 . A method as claimed in  claim 24 , wherein said voltage and current is regulated by a PID controller.  
     
     
         26 . A method as claimed in  claim 14 , further comprising mechanically separating each of said associated front and back curve mold halves subsequent to the application of the thermal gradient thereto by said infra-red energy means.  
     
     
         27 . An apparatus for demolding a plurality of lenses formed between corresponding front and back mold halves, said apparatus comprising: 
 a plurality of means each directing a predetermined amount of infra-red energy at a respective associated one of said mold halves to thereby provide a controlled thermal gradient between said mold halves.    
     
     
         28 . An apparatus for demolding a plurality of contact lenses formed between corresponding front and back curve mold halves which are positioned in a regular array on a pallet, after formation and curing of said lenses, each of said mold halves having an arcuate central portion and an annular flange portion, said apparatus comprising: 
 a plurality of means each directing a predetermined amount of infra-red energy at a respective associated one of said back mold halves to thereby provide a controlled thermal gradient between each of said back mold halves and the therewith associated infra-red energy means.    
     
     
         29 . A method of demolding a plurality of contact lenses formed between corresponding front and back curve mold halves which are positioned in a regular array on a pallet, after formation and curing of said lenses, each of said mold halves having an arcuate central portion and an annular flange portion, said method comprising: 
 separately having sources directing predetermined amounts of infra-red energy at a respective associated one of said back mold halves to thereby provide a controlled thermal gradient between each of said back mold halves and the therewith associated infra-red energy.    
     
     
         30 . An apparatus for demolding a lens formed within a mold assembly, said apparatus comprising: 
 an infra-red emitter and a reflector, wherein said reflector reflects radiation at said mold assembly.    
     
     
         31 . The apparatus of  claim 30  wherein said reflector comprises an upper portion having a conical, circular elliptical or circular parabolic shape.  
     
     
         32 . The apparatus of  claim 31  wherein said reflector further comprises a second portion connected to said first portion wherein said second portion has a conical shape.  
     
     
         33 . The apparatus of  claim 32 , wherein said reflector further comprises a nozzle connected to said second portion.  
     
     
         34 . The apparatus of  claim 31  wherein said reflector further comprises a nozzle connected to said first portion.  
     
     
         35 . An apparatus for demolding a lens formed within a mold assembly, said apparatus comprising: 
 an infra-red emitter and a reflector, wherein said reflector comprises a reflector having a surface roughness less than 0.3 micrometers RMS.    
     
     
         36 . The apparatus of  claim 35  wherein said surface roughness is less than 0.2 micrometers RMS.  
     
     
         37 . The apparatus of  claim 35  wherein said surface roughness is less than 0.1 micrometers RMS.  
     
     
         38 . An apparatus for demolding a lens formed within a mold assembly, said apparatus comprising: 
 an infra-red emitter and a reflector, wherein said reflector comprises a gold coating of between from 1.3 to 2.9 micrometers.    
     
     
         39 . The apparatus of  claim 38  wherein said reflector further comprises a primer layer between from 7 to 25 micrometers thick.