| 摘要 |
PURPOSE:To measure the photoelasticity of a substance for showing the light transmittivity in a near infrared-ray area, by using a halogen lamp as a light source, providing a 1/4 wavelength plate between a polarizer and an object to be measured, and between the object to be measured and an analyzer, respectively, and detecting exiting light with a vision camera. CONSTITUTION:A measurement in the main stress direction of an object to be measured 2 is executed by removing a 1/4 wavelength plate 9a placed between a polarizer 7 and the object to be measured 12, and a 1/4 wavelength plate 9b placed between the object to be measured 12 and an analyzer 16, and rotating the polarizer 7 and the analyzer 16. Also, by attaching the wavelength plates 9a, 9b, the main stress difference of the object to be measured 12 is measured. Moreover, a visible light or a near infrared-ray is generated from a halogen lamp 3, a light beam of the lamp 3 is brought to a spectrum to a monochromatic light by a diffraction grating 4, and the visible light or the near infrared-ray is detected by a vidicon camera 19 through the polarizer 7 having a polarization characteristic, and the analyzer 16, by which photoelasticity can be measured with regard to a substance such as a silicon single crystal body for showing the light transmittivity in a near infrared-ray area, as well.
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