| 摘要 |
PURPOSE:To detect temperature of a motor or the like without affection of a strong electromagnetic field by connecting a sensor that consists of a rod lens, polarizer plate, temperature dependent double refraction crystal, wavelength plate and reflection body to the tip end of an optical fiber. CONSTITUTION:Light beam incident from the optical fiber 1 is diffused in the focusing rod lens 2 of 1/4 pitch so that the beam diameter may be expanded, and is made parallel to apply itself to the polarizer plate 4. Only the polarized component that agrees with the direction of polarization is taken by the polarizer plate 4 and applied to the double refraction crystal 5. The light beam is divided into an ordinary ray and an extraordinary ray and a retardation is developed because the C-axis of the double refraction crystal 5 is shifted from the direction of polarization of the polarizer plate 4. When the light ray moves back and forth in the wavelength plate of 1/4 pitch and passes through the double refraction crystal 5 again and reaches the polarizer plate 4, an elliptic polarization is produced, only the component that agrees with the direction of polarization of the polarizer plate 4 is taken. |
