The world's earliest surgical shadowless lamp was invented in the 1920s in England by a French professor, Weyland. Weyland placed a 100-watt bulb in the center of a refractive lens formed by a number of narrow plane mirrors placed uniformly on the dome of the shadowless lamp, so that the entire shadowless lamp is a conical shape to eliminate the cusp.
The second reform of the shadowless lamp is in the 30's and 40's France's single-lamp shadowless lamp and the U.S. track-type shadowless lamp. At that time, the light source used is incandescent bulbs, the power of the bulb can only reach a maximum of 200 watts, the filament around the area of the large, can not control the light path, difficult to focus; reflector use of copper polished molding, is not easy to reflect, so the illumination of the shadowless lamp is extremely low.
To the fifties, in order to improve the illumination of the shadowless lamp, hole type multi-lamp shadowless lamps have been produced and used in Europe and Japan. This type of shadowless lamp increased the number of light sources, with high purity aluminum as a small reflector, improve the illumination of the shadowless lamp.
However, this type of shadowless lamp due to the increase in the number of bulbs, so that the temperature of the shadowless lamp rises very quickly, easy to cause discomfort to the doctor as well as the surgical site of the tissue of the drying, is not conducive to the patient's postoperative recovery.
In the early eighties, the daily newspaper began to produce halogen lamp light source of cold light hole type surgical shadowless lamp. In the late eighties and early nineties, the overall reflection type surgical shadowless lamp was introduced. This kind of shadowless lamp adopts computer-aided design technology to design the reflector surface, the surface is molded by industrial stamping in one go to form a multilateral reflector. The light source of this type of shadowless lamp is not only as bright as daylight but also has no shadows.
Expanded:
Principle of Shadowless Lamp
Shadowless Lamp in fact can not be "shadowless", it is only to lighten the original shadow, so that the original shadow is not obvious. Shadows are formed when light strikes an object. Shadows are different everywhere on earth. If you look closely at a shadow under electric light, you will see that it is particularly dark in the center and slightly lighter around the perimeter.
The part of the shadow that is particularly dark in the middle is called the umbra, and the part that is gray around it is called the penumbra. These phenomena are closely related to the linear propagation of light. If you put a column-shaped tea-cone on the table and light a candle next to it, the tea-cone will cast a clear shadow.
If two candles are lit next to the tea canister, two overlapping shadows will be formed without overlapping. The overlapping part of the two shadows, where no light reaches them at all, is completely dark, which is the main shadow; the area next to the main shadow, where only one candle can be lit, is the half-light, half-dark penumbra. If three or even four candles are lit, the penumbra will gradually shrink, and many layers will appear in the penumbra.
Objects in the electric light can be generated by the shadow and penumbra composed of shadow, is also the same reason. Obviously, the larger the area of the illuminated object, the smaller the penumbra will be. If we light a circle of candles around the above tea canisters, this time the shadow completely disappeared, the penumbra is also too faint to see. Scientists based on the above principle made a shadowless lamp for surgery.
It will be a great luminous intensity of the lamp in the lamp plate arranged in a circle, synthesized into a large area of light source. In this way, the light can be irradiated from different angles to the operating table, both to ensure that the surgical field of vision has sufficient brightness, but at the same time will not produce obvious benign shadow, so called shadowless lamp.
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