GB190605500A - Improvements in Measuring Distances - Google Patents

Abstract

5500. Zeiss, C., [Firm of]. Dec. 23, 1905, [date applied for under Patents Act, 1901]. Range-finders; optical. prisms. -Relates to a method of range-finding depending upon the use of a triple reflector, such for instance as is shown in Specification No. 21,856, A.D. 1903, so modified as to reflect beams of light at small but constant angles of inclination to the incident beam. This is done by inclining the reflecting-surfaces at other than right-angles. The angle with the incident beam at which any particular triple reflector reflects a particular beam being known, it is only necessary to measure the distance between these two beams at any spot to determine the distance of the reflector. In general, a triple reflector as thus modified splits up an incident beam into six reflected ones, but these may be coalesced in pairs in various ways. Fig. 2 shows diagrammatically the method in use. A beam of light is projected from B by a mirror b on to a distant triple reflector a, by which the beam is split up into two beams which return to B as shown, one to' the right and one to the left. The distance of any one of these beams from B, the triple-reflector constant being known, gives the distance. The reflector may be in the form of a solid tetrahedron of glass with a plane inlet and outlet surface and with the non-effective solid angles removed as shown in Fig. 1. The reflector may have a collecting lens mounted in front of it, or the entrance surface itself may be convex. [Reference has been directed under Patents Act, 1902, to Specification No, 9129, A.D. 1903.]