| 摘要 |
PURPOSE:To compensate the temperature characteristic and the secular change of optical constituting elements which give no disturbance to a system to be measured, by using two polarizing films, namely, a movable polarizing film and a fixed polarizing film. CONSTITUTION:Since the light from a light emitting diode 3 is polarized by a movable polarizing film 2 and is polarized furthermore by a fixed polarizing film 5, the quantity of light incident to a photodiode 4 for detection is dependent upon the relative angle between films 2 and 5 and shows a change approximate to a sine curve of period 180 deg.. A part of this curve where the quantity of incident light is changed most linearly for the rotation angle of the film 2, is selected to obtain a voltage approximately proportional to the rotation displacement as a detection voltage V. |
