PURPOSE: To increase the formation speed of a film and to form a thin film of any raw material by manufacturing fine particles and depositing fine particles on a substrate at independent stages respectively.
CONSTITUTION: Fine particles 7 for film formation are manufactured independently. In this case, vapor-phase reaction is unnecessary, so any raw material is made into fine particles 7. The fine particles 7 of this film raw material are fallen from the upper part of an electric furnace 3 together with a carrier gas for uniform sedimentation. When the objective substrate 6 is preheated, the fallen fine particles 7 are deposited closely to form a good film. The substrate 6 is taken out so as to make the deposited film into glass, and heated above the fusion point of the raw material, obtaining the light guide film. When a film as a cladding is further formed, fine particles 7 containing a component having a low refractive index as a fine particle raw material are deposited and made into glass to obtain a film of multilayered structure.
KOBAYASHI SOUICHI
NISHI NORIO
