APPARATUS FOR INSPECTION OF SYNTHETIC RESIN FILM WELD PART

PROBLEM TO BE SOLVED: To make discrimination of irregularity in weld existing in a weld part of a synthetic resin film by a method wherein an arranged space of an inspection object position of the weld of the synthetic resin film is formed between mutual two sheets of polarizing filters arranged by being opposed to each other. SOLUTION: An arranged space S of an inspection object position of a weld part 51 of a synthetic resin film is formed between mutual two sheets of polarizing filters 1, 2 arranged by being opposed to each other. Then, a light source 3 casting light to an inspection objective position is provided. For this inspection apparatus, both of that in which light passing through the polarizing filter 2 becomes plane polarized light and that in which the light passing through the polarizing filter 2 becomes circular polarized light may be used. The plane polarized light is light capable of being decomposed into two plane polarized lights of the same phase which are vertical to each other, and the circular polarized light is light capable of being decomposed into two plane polarized lights wherein they shift mutually by 1/4 wavelength, are equal in size, and vertical to each other.