GB885508A - Improvements in optical means for indicating or recording a path of movement - Google Patents

Abstract

885,508. Optical pointers; mirror arrangements. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Feb. 13, 1959 [Nov. 13, 1957], No. 35354/57. Class 97(1). A movable optical reflecting system which can receive a spot of light from a fixed source and reflect it as a moving spot on to a fixed screen and comprises a pair of bodies having plane co-operating reflecting surfaces arranged in constant angular relationship to each other and to a common plane of reference so that the directions of incidence and reflection of the spot open and by one of these surfaces will lie in a plane orthogonal to the plane in which will lie the directions of incident and reflection of the spot upon, and by the other surface, the bodies being movably mounted so as to be constrained to translation without altering the angular relation of the reflecting surfaces to each other and to the plane of reference and so that certain movement corresponding with that of a moving element, operatively connected to one or both of the plane reflecting surfaces so that the or each surface participates in the movement of the element, will be split up into components and then recombined in the movement of the spot upon the screen. As shown in Fig. 1 the reflecting system may comprise two plane mirrors 1, 5 movable respectively in the Y plane and X plane so as to reflect, as a moving spot on a screen 4, a light spot projected on to mirror 1 by lamp 2 and lens 3. In this case, the moving spot traces out a resultant path. In order to trace out the actual path in a plane, the arrangement of Fig. 2 may be used, this arrangement comprising reflecting surfaces 9, 10, of which the surface 9 is carried by a table 7 movable in the Y direction while surface 10 is carried by a table 8 movable in the X direction on the table 7. The arrangement of Fig. 2 may be further modified by the two reflecting surfaces being carried by a single table 7 movable in both directions under the control, for example, of a pantograph linkage. Magnification or reduction may be provided by a lens system disposed between the moving mirrors and the fixed screen or the latter may be viewed through a magnifying lens system. One of the carriages or tables may carry a stylus which can move over a workpiece under inspection, as described in Specification 882,075. And, in a further form, the fixed screen may be replaced by a photographic film or plate. Specification 885,507 also is referred to.