Patent GB-608628-A (GB)
Title: Equipment for demonstration and display
IPC: G09F27/00
Filed: 1945-11-22
Abstract: 608,628. Optical projection apparatus. HANSEL, C. W. Nov. 22, 1945, Nos. 31531 and 32697. [Class 97 (i)] [Also in Group XVIII] Equipment for the demonstration and display of a variety of objects for use in conjunction with projection apparatus of short and long throw types, comprises a supporting framework carrying a display stage which has a movable or removable screen 6, provision on the framework for mounting an additional screen 18 alternatively in horizontal or vertical position, and a mirror 1 operating in association with the display stage, the movable or removable screen 6, or the additional screen 18; the height of the display stage 6 above the bottom of the framework, and the optical spacing between the stage and the said additional screen, whether in the horizontal or vertical position, is such as to permit the use of a short-throw projector in alternative positions in the equipment to produce an image of appropriate size on the screen in use. In the arrangement shown in Fig. 1, the mirror 1, which is supported on posts 4 by sliding fitments 5, is disposed above a demonstration table 3 carrying on its top surface a removable translucent panel 6 which may serve as a stage on which objects for display may be supported and also as a screen for optical images. The space below the table top is darkened by curtains or opaque panel 14, except for an aperture 7 for the admission of a light beam from a longthrow projector; this beam is reflected on to the screen 6 by a mirror 8 which is supported on a wheeled frame 9 under the table top. The screen 6 is protected from stray light by curtains 11 and a foldable shield 12. This apparatus is provided additionally with means in the form of supports 19 for supporting the screen 18 either horizontally below the mirror 1 as shown in Fig. 3 or vertically in front of the mirror 1 as shown in Fig. 4. A short-throw projector 17 may be mounted on the bottom of the framework for producing an image on the screen 6, or it may be disposed on the display stage for projecting an image on to the screen 18 when the latter is arranged either horizontally or vertically; if desired, the projector, when disposed on the display stage, may be associated with a mirror for effecting a longer throw. The projector 17 may also be mounted on a shelf outside the demonstration table for co-operating with a mirror in order to produce an image on the screen 6, or it may be arranged in association with a mirror 22 as shown in Fig. 8 for reflecting a light beam on to an opaque screen 16 on the stage. Projection apparatus for use on the display stage in the arrangements shown in Figs. 3 and 4 may comprise a number of optical units 23, 24, 25, Fig. 10, each of which is arranged in a cubical housing: the unit 23 comprises a condenser lens 26 and lamp 27, the unit 25, an inclined mirror 28 and lens 30, and the unit 24 an inclined mirror 29. By suitable selection of the focal length of the objective 30, this arrangement could be used for producing an image of a lantern slide 31 on either the horizontal or vertical screen, or for the projection on to these screens of 35 mm. films or micro films. If desired, a projector for lantern slides may be mounted on the display stage, together with a unit incorporating an inclined mirror for producing an image on either the horizontal or vertical screen; both the projector and unit may be slidably mounted on rails in this arrangement. Examples are given of the relative dimensions of the height of the stage above the bottom of the framework, and the optical distance of the horizontal screen 18 from the stage so as to permit the use in various positions in the framework of different kinds of short-throw projectors. The apparatus may also be used with a long-throw projector which is adapted to project a light beam on to the mirror 1 for reflection downwards on to the screen 6 on the display stage; the image focused on this screen is then viewed in the mirror 1. The equipment may be embodied in display cabinets and shelves, shop window equipment, &c., and accessory display apparatus such as turntables, belt conveyers, television apparatus, clockwork mechanism, &c. may be incorporated in the equipment. The second Provisional Specification describes also the basic structure as being provided with parallel guides at standard levels, between which the standard projection units can slide so that they can be quickly moved into their desired positions.