JPH04220508

PURPOSE:To enable correct measurement by setting an incident angle of measurement light when it is incident on a light permeable sample to such an angle that a light path of the measurement light incident on the sample is deflected by diffraction of the light and is not incident on a light receiving...

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Bibliographic Details
Main Authors TAKAOKA KAZUHIRO, KATO KINYA
Format Patent
LanguageEnglish
Published 11.08.1992
Edition5
Subjects
MEASURING
MEASURING ANGLES
MEASURING AREAS
MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS
PHYSICS
TESTING
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Summary:PURPOSE:To enable correct measurement by setting an incident angle of measurement light when it is incident on a light permeable sample to such an angle that a light path of the measurement light incident on the sample is deflected by diffraction of the light and is not incident on a light receiving member. CONSTITUTION:A measurement optical system comprises a light emitting member 10 and a light receiving member 11 which are oppositely placed so that an angle made when a light path of measurement light is incident to a side of a sample 6 is not 90 deg. but 70 deg. for example, while a sample holder comprises a carrier 12 for housing the sample 6 and a carrier table 13 and moves relatively to the measurement optical system. Light is emitted from the member 10, and the table 13 is moved from over to below the carrier 2. At this time from a photoelectric conversion signal detected by the member 11, a waveform processing circuit 18 identifies a position where the light was not able to be detected to Hi or Low and also reads a relative movement amount of the measurement optical system and the sample holder from an encoder 15 pulse, so that the amount is subjected to calculation in a CPU 21 to have thickness correctly calculated.
Bibliography:Application Number: JP19900404890