OPTICAL FIBER TYPE INTERFERENCE FILM THICKNESS METER

• Main Authors: NEMOTO ISAO, INOUE KATSU
• Format: Patent
• Language: English
• Published: 14.02.1990
• Subjects: MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; TESTING

PURPOSE:To facilitate the measurement of a film thickness in an atmosphere differing from atmospheric air such as vacuum by using a branch type optical fiber for irradiation of a white light and for detection of reflected light to set a common end of the optical fiber airtight in an another atmosphere. CONSTITUTION:An incoming branch end 12 of a branch type optical fiber 10 is fixed on a white light source 8 while an outgoing branch end 14 thereof is fixed on an image interference meter 20. On the other hand, a common end 13 of the branch type optical fiber 10 is introduced into a measuring chamber 50 with the atmosphere differing from atmospheric air 60 and the tip 17 thereof faces a sample 52 to be measured having a surface film 53 on a measuring platform 55. The measuring chamber 50 is surrounded by a diaphragm 58 exclud ing a through part 15 sealed airtight. With the supply of a power source 1, light of a lamp 2 is emitted to the sample 52 via the tip 17 of the common end at the incoming branch end 12 and the reflected light is introduced to the image interference meter 20 at the outgoing branch end 14. Thus, an interference fringe 29 is made to form an image on a photo detecting surface of a photo diode array 30 to detect a film thickness.