Patent ID: 6921911
Filing Date: 2005-07-26
Classification: G01F,G02B,Y10S

Abstract:
1. A method of determining a filling level in a liquid-filled container using a light guide body which projects into the volume of the container and which has an end face for the entry and exit of light and side faces providing reflection faces separated by steps, wherein light introduced into the light guide body at said end face is totally reflected at those reflection faces which are not immersed in liquid in the container but is refracted into the liquid at immersed reflection faces, wherein light totally reflected by a reflection face is reflected back to the end face as a light beam, and wherein at least one measurement signal of the intensity of the light beam totally reflected is provided for each step and separately detected as a separate measurement of the intensity of the light reflected by each step relative to other steps, said at least one measurement signal being evaluated and checked, said evaluation and checking including plausibility checking for recognizing and eliminating measurement errors.