Patent ID: 7058270
Filing Date: 2006-06-06
Classification: B29D,G02B

Abstract:
1. A process for producing a preform for a plastic optical fiber having a refractive index distribution which gradually increases from the outer periphery toward the center thereof, comprising inserting a 1 st plastic tube (inside diameter: d 1 i , outside diameter: d 1 o ) made of a first polymer (refractive index: n 1 ) in a cylindric polymerization reactor (inside diameter: d 0 , d 1 o ≦d 0 ) and inserting a 2 nd plastic tube (inside diameter: d 2 i , outside diameter: d 2 o , d 2 o ≦d 1 i ) made of a second polymer (refractive index: n 2 , n 2 >n 1 ) into the 1 st plastic tube, wherein the reactor, the 1 st and 2 nd plastic tubes are coaxially positioned; injecting a precursor of a third polymer (refractive index: n′, n′>n 2 ) into the inner side of the 2 nd plastic tube and a precursor of a fourth polymer (refractive index: n″, n 1 <n″<n 2 ) into the space formed between the 1 st and 2 nd plastic tubes; and polymerizing and curing the precursors to form a core of the perform.