TRANSFER AND INJECTION MOLD TECHNOLOGY IN ULTRA-COMPACT TYPE PHOTOINTERRUPTER

Along with the development of compact type electronic equipment with components high density mounting, demands for a SMD (Surface Mount Device) type optical device are expanding. In response to this movement, we have developed a SMD type photointerrupter adopting double mold method by using PPS (Polyphenylene Sulfide) in second mold. The improvement in thermal stability of epoxy double transfer mold makes it possible to realize the first optical device using thermal stable PPS (thermal deformation temperature:260-degrees-C or more). Technical factors in the development of this photointerrupter are as follows: (1) Development of high fluidity PPS (Conventional ratio:1.33 times), (2) Low temperature injection second mold technology of PPS (Mold temperature:100-degrees-C or less, Resin temperature:310-degrees-C or less), (3) Improvement in mechanical characteristics and high stability due to annealing treatment after molding. This paper describes the basic material development and structure.