Title:
METHOD OF MEASURING CHARACTERISTIC OF PLASTIC FILM BY USING INFRARED RAY
Document Type and Number:
Japanese Patent JPS5839931
Kind Code:
A
Abstract:
In the present publication, a method is described for the measurement of the properties, particularly of the thickness, of a plastic film (2) by transmitting infra-red radiation (1) through the film (2) to be measured, whereby part of this radiation is absorbed in the film (2) concerned. The face, form, and position of the plastic object to be measured as well as irregularities in the structure of the material cause variations of intensity in the absorption measurement that do not illustrate the quantity to be measured, e.g. thickness. The object of the present invention is to eliminate said disturbance effects. The invention is based on that the disturbances caused by refraction and scattering of the IR beam as well as by unhomogeneity of the material are compensated by separating from the radiation that has passed through the plastic film two different wave-length bands and by measuring the ratio of the intensities of the different wave-length ranges. Since the refraction factor of plastic material is practically constant within two wave-length ranges placed close to each other, refraction does not affect the ratio of intensities. The different radiations (10, 14) are passed to their respective detectors (12, 13; 16, 17) for detection. Finally, the ratio of the output signals of both detectors (12, 13 and 16, 17) is calculated, whereby the value of the desired property, e.g. thickness, at the measurement point can be established on the basis of the said ratio.
Inventors:
SAURI YUHANI TORUMARA
Application Number:
JP14317682A
Publication Date:
March 08, 1983
Filing Date:
August 18, 1982
Export Citation:
Assignee:
TOTSUPUUEIBU INSUTSURUMENTSU O
International Classes:
G01B11/06; G01N21/35; (IPC1-7): G01N21/35
Attorney, Agent or Firm:
Takehiko Suzue