Optical sensor for detecting liquid medium
AssigneeBellhouse Technology Limited
InventorsBrian J. Bellhouse, Stephen Goodman
Life of this patent
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Abstract
An optical sensor comprises a probe (10) and an annular optical element (13) coupled optically to a pair of optical fibres (18). Light transmitted down one fibre is reflected around the element (13) and back up the other fibre to a photodetector. The level of light received by the photodetector is dependent upon the amount of light lost from the element (13) as a result of characteristics of the surrounding medium. The presence or absence of a surrounding liquid medium may thus be sensed and a motor (34) operated to suck liquid up through the probe, when the liquid is present.
Claims29
An optical sensor comprising an elongate probe;
- a light guide extending from a light source, along the probe towards a tip of the probe and back along the probe to a photodetector, the light guide including, adjacent to the tip, a rigid element, which has a radially outer substantially cylindrical surface providing substantially total internal reflection of light passing circumferentially around the probe within the element, or loss of light, depending on the optical properties of a surrounding medium, and which is mounted in a substantially cylindrical portion of the probe so that the outer surface of the element is substantially flush with the outer surface of that portion of the probe.
Dependencies are inferred from the claim text.