| 摘要 |
<p>PURPOSE:To make it possible to detect from outside whether liquid exists in a vessel with a large diameter, by making the light penetrate through the vessel, and detecting the change of light path direction to discriminate whether liquid exists. CONSTITUTION:The light emitting element 8 and the photo detector 9 are fixed confronting to each other. The light axis 12 connecting the elements 8 and 10 intersects the vessel 6, and crosses the internal wall of the vessel 6 on the incidence side with some inclination. The light axis is also aligned so as to be parallel to the surface of liquid in the vessel 6. The light from the element 8 refracts at both the external and the internal surfaces of the side wall of the vessel 6. In case no liquid exists on the light axis in the vessel 6, the light travels along (a) and reaches the element 10. On the contrary, in case liquid exists on the light axis in the vessel 6, the light refracts at the internal surface of the vessel 6 on the incidence side and deviates from the light axis. Therefore the light travels along (b) and does not reach the element 10. Thus the detection signal of the element 10 changes according to whether the liquid in the vessel 6.</p> |
