principle
The shadowless lamp is actually not “shadowless”, it just lightens the umbra so that the umbra is not obvious. Shadows are formed when light hits an object. Shadows are different everywhere on the earth. If you carefully observe the shadow under the electric light, you will also find that the middle part of the shadow is particularly dark, and the surrounding area is slightly lighter. The particularly dark part in the middle of the shadow is called the umbra, and the dark part around it is called the penumbra. These phenomena are closely related to the linear propagation of light. If you put a cylindrical tea tube on the table and light a candle next to it, the tea tube will cast a clear shadow. If two candles are lit next to the tea canister, two overlapping but not overlapping shadows will be formed. The part where the two shadows overlap has no light at all and is completely black, which is the umbra; the place next to the umbra where only one candle can be illuminated is the half-shadow penumbra. If three or even four candles are lit, the umbra will gradually shrink, and many layers will appear in the penumbra. This is also the reason why objects can generate shadows composed of umbra and penumbra under electric light. Obviously, the denser the light source of the luminous object surrounds the illuminated object, the smaller the umbra. If we light a circle of candles around the above-mentioned tea cylinder, then the umbra will completely disappear, and the penumbra will be too faint to be seen. Scientists made a shadowless lamp for surgery based on the above principles. It arranges the lamps with high luminous intensity in a circle on the lamp panel to synthesize a large-area light source. In this way, the light can be irradiated onto the operating table from different angles, which not only ensures sufficient brightness of the surgical field of view, but also does not produce obvious umbra, so it is called a shadowless lamp.
composition
The surgical shadowless lamp is generally composed of a single or multiple lamp heads, which are fixed on the cantilever and can move vertically or circularly. The cantilever is usually connected to a fixed coupler and can rotate around it. The shadowless lamp adopts a sterilizable handle or a sterilizable hoop (curved track) for flexible positioning, and has automatic braking and stop functions to control its positioning, and maintain a suitable space on and around the surgical site. The fixture of the shadowless lamp can be placed on the fixed point on the ceiling or wall, or on the track of the ceiling.
Type and Evolution
The development of surgical shadowless lamps has experienced the development of porous shadowless lamps, single reflection shadowless lamps, porous focus shadowless lamps, LED surgical shadowless lamps, etc.
The picture on the right is a traditional multi-hole shadowless lamp, which mainly achieves the shadowless effect through multiple light sources. The picture on the left shows a single reflection shadowless lamp that is more popular in China, which is characterized by high illuminance and focusability.
More popular in foreign countries is the porous focusing surgical shadowless lamp, which is a higher-end surgical shadowless lamp. In addition, the LED surgical shadowless lamp that is becoming more and more mature has gradually entered people’s minds with its gorgeous shape, long service life, natural cold light effect and energy saving concept. in the field of vision.
use
For shadowless lamps installed on the ceiling, one or more transformers should be installed in the remote control box on the ceiling or wall to convert the input power supply voltage into the low voltage required by most light bulbs. Most shadowless lights have dimming controls, and some products can also adjust the light field range to reduce the light around the surgical site (reflections and flashes from bed sheets, gauze or instruments can be uncomfortable to the eyes).
