The illuminator in the 3D World viewer<\/a> is an edge-lit panel. It works by shining a light into the polished bottom-edge of a lexan sheet. Through internal reflections, the light is directed out one of the flat surfaces of the sheet. It provides a very even light in a very thin package. I’ve always considered edge lighting to be the most desirable way to light a slide viewer. I’m very pleased to see 3D World using the concept in their newest viewer.<\/p>\n <\/a><\/p>\n Several years ago, I modified one of the 3D World steal-the-light<\/a> (STL) viewers and inserted an edge-lit panel. I used a panel with a fluorescent light source, and powered it from the wall rather than from batteries. The result was an extremely thin, very bright light that hid in the back of a my fixed-focus viewer.<\/p>\n In the intervening years, I have considered installing a battery pack in my illuminated viewer, but the power demands of the fluorescent light made that impractical. I have also tried several times to build an edge-lit panel using LEDs in place of the fluorescent tube. The result would have been an instant-on light with a smaller electronics package and lower power consumption.<\/a>I was never able to design an LED-lit panel which provided light sufficiently even for slide viewing.<\/p>\n Thank goodness 3D World has succeeded where I was stymied. They have designed and built an LED-lit panel suitable for use in a slide viewer. Because it is instant-on (unlike fluorescent), it can have a momentary switch. Because it has a momentary switch and LEDs with low power consumption, it can be battery powered. Because it’s edge-lit, it is very thin and because it’s very thin, the final viewer can be very compact.<\/p>\n I now have three illuminated medium format viewers:<\/p>\n<\/a>How Does It Perform<\/h3>\n