USING THE PULL OF A BEAM OF LIGHT ON A LIQUID SURFACE TO EXPLAIN COLOUR SIGHT WITH THE PROVISION OF A CHROMATIC SELECTION DEVICE

摘要

1414601 Photo-electric detection of photon induced increases of liquid level A P PEDRICK 12 Feb 1974 06269/74 Heading G1A The Specification refers to the discovery that a laser or like strong light beam can cause localized raising of a liquid surface. The invention exploits this discovery, with reference by way of example to its application to discriminating between cats of different colours. Light from sources 11, 12 are reflected from the back of a cat 1 entering an access tunnel 2. The reflected light is effectively amplified by directing it on to a photo-cell 14 whose output controls the intensity of the beam from a source 15. The latter beam strikes a liquid surface 16, causing the liquid surface to rise to an extent dependent on the energy of the reflected light from the cat's back. Thus, e.g. in accordance with whether the cat is black or ginger, the deflection of a further light beam 6 reflected at the liquid surface, can be such as to energize one or the other of two photo-cells PC1, PC2. These cells can be used to operate a cat flap 3. The Specification also contains a theoretical discussion of the phenomenon on which the invention is based.