| 摘要 |
<p>Optical point fluid level sensor has a prism (40) having internal reflection dependent upon fluid level. Electromagnetic energy, pref. light, passes from a source (16) to a detector (18) via a lens (30) coupled to the prism and back through the lens. The angle of entry of the energy to the lens differs from the two passes. Pref. the prism is of Schott glass, polysulphone, or polyethersulphone, Pref. the lens is a GRIN lens. The energy crosses the lens axis and exits axisymmetrically when internally reflected within the prism.</p> |
