DE29808342U1 - Illuminated desk, especially for viewing / editing transparency templates - Google Patents

Description

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Appendix 1 Page 1/2 Lightbox Moritz Eisele 07.05.1998

Description

Light table, especially for viewing/editing transparent templates

Light consoles (panels/tables) of the usual design have a ground glass screen and one or more light sources behind it. In the simplest case, the distribution of the light across the ground glass screen is achieved via the distance between the light source and the ground glass screen without any additional measures. In some cases, more or less complex mirroring is used to achieve more or less even distribution, or attempts are made to achieve even illumination by using many light sources. The evenness of the illumination is therefore dependent, among other things, on the distance of the light source(s) from the ground glass screen, which results in a minimum height for light consoles of the conventional design, which is far higher than that required to simply accommodate modern light sources.

The invention specified in the protection claim is based on the problem of creating a light box with a minimal height, limited only by, for example, the dimensions of modern miniature fluorescent tubes and the necessary additional devices (ballast), while at the same time satisfying the requirement for uniform illumination of the same.

The way the invention works is based on the known possibility of using a glass plate as a light guide. Light rays that enter the glass plate at a flat angle at one edge are reflected through it to the opposite edge (total reflection, see Appendix 3, page 1, Figure 1). If the glass plate has a defect on its surface (groove, scratch), the light that occurs here is not simply reflected but scattered; for the observer looking at the surface of the plate, the relevant area appears to glow (see Appendix 3, page 1, Figure 2). Advertising signs (neon signs), acrylic glass plates into which lettering and/or images that appear to glow are milled, make use of this effect and are becoming increasingly popular. The realization that, according to the described effect, the light emission to the top and/or bottom of a glass plate illuminated from the side can be controlled as desired by simply scratching the top and/or bottom of the plate, is the basis for the solution to the described problem of uniform light distribution with a minimized construction height.

To achieve uniform illumination, it is important that the decrease in light intensity with increasing distance from the light source is taken into account by the distribution of the grooves. This means that with increasing distance from the light source, their density must increase uniformly, in line with the decrease in light intensity, so that in the area close to the light source, a lot of light from the still "intact" glass surface is reflected into the area further away and only then scattered.

In the manner described, in conjunction with the currently available light sources (miniature fluorescent lamps), it is possible to reduce the height of the devices mentioned and similar ones to less than 20 millimeters. This offers considerable advantages in handling (e.g. when used as a table device for sorting or tracing), generally means less space is required (also advantageous when installed in tables or other devices) and aesthetic advantages (use as a wall light).

Appendix 1 Page 2/2 Lightbox Moritz Eisele 07.05.1998

Example of implementation - see Annex 3, page 2, 3 and

Figure 3, page 2 : sectional drawing Figure 4, page 3 : perspective exploded drawing Figure 4, page 4 : isometric view of the device

(1) Light source (miniature fluorescent tube, here OSRAM FM 11W)

(2) clear acrylic glass plates, each with coarse sandpaper on the back as described, edges polished

(3) Reflector

(4) Work/light surface made of white, translucent acrylic glass

(5) Rear wall, mirrored on the inside

(6) Covers, opaque (here sheet steel)

(7) Ballast for fluorescent tube

(8) Frame parts (here aluminium profiles)

Claims (1)

Appendix 2 Page 1/1 Lightbox Moritz Eisele 07.05.1998 Protection claims Light table, especially for viewing and processing transparent originals such as slides or X-ray images, which has a translucent work surface that is evenly illuminated from the back, characterized that there is a clear (acrylic) glass plate under the work surface, into which the light from the light source shines from the side and which has fine depressions (grooves, scratches) on at least one of its two surfaces parallel to the work surface (top and bottom), the density of which is constant parallel to the illuminated edge and increases perpendicular to it with increasing distance from the edge (light source).