GB689231A - Method and apparatus for providing from plane images the appearance of a solid object - Google Patents

Abstract

689,231. Optical projection apparatus. MONTEBELLO, A. R. L. DE. Dec. 31, 1947, No. 35313/47. [A Specification was laid open to inspection under Sect. 91 of the Acts, Dec. 31, 1947.] Classes 97 (i) and 98 (ii). [Also in Group XV] A special plane image or picture of an object is made such that when subjected to a hidden source of illumination of intensity I, the various parts of the image show approximately the same intensity of illumination as the corre. sponding parts of the object would show when the latter is illuminated by a light source of intensity i which is less than I. The image so made and illuminated is stated to give the illusion that the viewer is looking at the actual object illuminated with an intensity i. One manner of making the special image is to use a white material which can be rendered translucent or transparent and to copy the image thereon, modifying the light and dark parts to give the desired result; or a photograph on glass or film may be suitably intensified. Such an image 1 may be used in apparatus as shown in Fig. 3, comprising a casing 6 with vents 7, a rear source 2 of illumination of intensity I and a front viewing-aperture 8. The margins 3 of the image are so treated that when illuminated from the rear by the source 2 they appear to the viewer to be illuminated by light of intensity i, and a mirror 4<SP>1</SP> reflects a beam of light of the same intensity across the front of the image and along parts of the edges of the opening 8; this increases the illusion that the image is illuminated from a source of intensity i. Mirrors M may be placed perpendicularly to the image for the same purpose. An image 1, painted to have the characteristics set out above, may be directly illuminated, Fig. 5, by a concealed light source of intensity I, the light passing through a condenser 2<SP>1</SP> to illuminate the image, and through a diffuser 4<SP>1</SP> to illuminate the margin 3 with an intensity i. To reinforce the blacks of the image, a transparent screen 10 tendered opaque at the requisite parts or a suitably-treated reproduction on glass of the original may be employed. In a further modification, Fig. 6 (not shown), the image 1 is directly illuminated from the source 2 and a light-absorbent screen is mounted adjacent to the upper edge of the viewing aperture, the screen causing parts of the edges of the aperture and the visible part of the image-surround to be illuminated with an intensity i. Fluorescent paint may be used in making the image.