Patent ID: 6462350
Filing Date: 2002-10-08
Classification: G01N

Abstract:
An opto-electronic sensor for measurement of a first medium, the first medium having a first index of refraction, the measurement being effected by detection means disposed in a second medium having a second index of refraction, the sensor comprising:a window made from an optically transparent material having a third index of refraction greater than the second index of refraction, said window disposed between the first medium and the second medium for sealing the first medium with respect to the second medium, said window having a first surface adjacent to said first medium and a second surface adjacent to said second medium; a transmitter channel for irradiating first light along a first axis to pass through said window and into the first medium through said first surface; at least one receiver channel disposed in said second medium, said receiver channel detecting second light originate from interactions between said first light and the first medium, said second light passing through said window and into said receiver channel; and an evaluation unit connected to said receiver channel for processing information from said receiver channel, wherein said first surface, said second surface and said first axis are oriented such that third light originating from reflection of said first light on said first surface is incident on said second surface at an angle which exceeds a critical angle for internal reflection at said second surface, whereby said third light is reflected from said second surface back into said window and does not enter into said receiver channel.