GB605562A - Improvements in and relating to episcopic projection - Google Patents

Abstract

605,562. Optical projection apparatus. MARTIN, B. April 30, 1945, No. 10853. [Class 97 (i)] In an episcopic projector an optical system or systems co-operate with a corresponding source or sources of light to project upon the object a beam or beams of light, each system comprising a frontally disposed truncated ellipsoidal reflector and a concentric refractor, the light source being disposed at the common focus of the reflector and refractor. Alternatively one light source may co-operate with a plurality of optical systems. In the form shown, light from a single lamp 5 is projected on to the object 4 through two optical systems each consisting of concentric ellipsoidal reflectors 12, 13 and a lens 14, a mirror 8 and a lens 9. Light is reflected from the object and an inclined mirror 2 into an objective with axis perpendicular to the plane of the figure. The illuminating system is in a housing separated from that which contains the object by a wall 11 with apertures 10 for the passage of the light beams. Heat filters may be provided in the light beams at 68. Uniformity of illumination may be controlled by adjusting the lenses 9. In another form of apparatus projection takes place directly from the object without the mirror 2, the two illuminating systems having no deflecting mirrors 8, and having separate lamps. In another form, two double illuminating systems as in the figure are provided side-by-side. In another form the illuminating system is placed at the bottom of the housing and the object is placed face downwards on a transparent panel at the top. Specification 534,455, [Group XI], is referred to.