| 摘要 |
PROBLEM TO BE SOLVED: To achieve miniaturization and high-precision in a level sensor for sensing levelness and obliquity. SOLUTION: The level sensor includes a light emitting diode 1 as a light source, a level 2 with liquid 2w included so as to save air bubbles 21, a light-receiving section 3 comprising four light-receiving elements 31-34, and an optical waveguide 4 consisting of transparent member which has both total reflection face 41 and reflection face 42 containing irregular shaped section 46 for incident light from the light emitting diode 1. It is characterized that diffused light from face luminescent parts formed on the reflection face 42 is illuminated to the level 2, light quantity distribution of projection light from air bubbles 21 on the light-receiving section 3 has a minimum point near the center axis of air bubbles 21, and also the light quantity distribution is monotonously-increased as it departs from the center axis of air bubbles 21 within nearly the same range as the radii of these air bubbles 21. Thus size of light-receiving face of the light-receiving section 3 can be made smaller than air bubble shade of the air bubbles 21 diameter, achieving miniaturization and high-precision. COPYRIGHT: (C)2007,JPO&INPIT
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