Principle of shadowless lamp
Shadowless lamp is not actually “shadowless”, it just reduces the umbra, making the umbra less obvious. Shadows are formed when light hits an object. Shadows are different everywhere on earth. Carefully observe the shadow under the electric light, and you will find that the shadow is particularly dark in the middle and slightly lighter around. The dark part in the middle of the shadow is called the umbra, and the dark part around it is called the penumbra. The generation of these phenomena is closely related to the linear propagation of light. If a cylindrical tea container is placed on the table and a candle is lit next to it, the tea container will cast a clear shadow. If two candles are lit next to the tea container, two shadows that overlap but do not overlap will be formed. The overlapping part of the two shadows has no light at all, and is completely black, which is the umbra; the place where only a candle can shine next to the umbra is the half-light and half-dark penumbra. If three or even four candles are lit, the umbra will gradually shrink and the penumbra will appear many layers. It is also true that objects can generate shadows composed of umbra and penumbra under electric light. Obviously, the larger the area of the luminous object, the smaller the umbra. If we light a circle of candles around the aforementioned tea container, the umbra disappears completely and the penumbra fades out of sight. Scientists have made a shadowless lamp for surgery based on the above principles. It arranges the lamps with high luminous intensity into a circle on the lamp panel to synthesize a large-area light source. In this way, light can be irradiated on 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.
The composition of the shadowless lamp
The surgical shadowless lamp is generally composed of single or multiple lamp heads, which are fixed on the cantilever and can be moved vertically or circularly. The cantilever is usually Attached to a fixed coupler and can rotate around it. The shadowless lamp adopts a sterilizable handle or a sterilized hoop (curved rail) for flexible positioning, and has automatic braking and stopping functions to control its positioning, maintaining a suitable space above and around the surgical site. Fixtures for shadowless lamps can be placed on fixed points on the ceiling or wall, or on the ceiling rails.
Five Requirements for Shadowless Lights
BrightnessRequirements
Surgery Outdoor surgeons must be able to precisely distinguish contours, colors, and movements. As a surgeon, therefore, a light intensity close to sunlight quality is required. 100,000 lux of light is determined to be equivalent to the brightness of the sun at noon. In addition, in the surgical environment, most of the light is absorbed rather than reflected, which means that the surgical shadowless lamp must provide greater brightness.
The shadowless lamp can produce a maximum brightness of 150,000lux, and the brightness can be adjusted steplessly. Only at this brightness can the surgeon have 50% of the visible light in the operating area.
No heat productionrequirements
Bright light comes with heat production. If heat is generated during the operation, it will bring great harm to the surgeon and the patient. Therefore, what we need during surgery is lighting that has only light and no heat.
Pathogen-freerequirements
One of the essential elements of surgery is to keep the number of pathogens during surgery to a minimum, so we Using the best surgical shadowless lamp shape design, with proper placement (behind the surgeon), the number of pathogens can be effectively controlled.
Color temperaturerequirements
The perception of color is determined by the color temperature of the light in which it is exposed, for example: the color temperature of sunlight is 5600kelvin; The light perceived by human studies at a color temperature of 5600 kelvin is white light. Therefore, experts recommend that the light color temperature in the operating room be at least 4000kelvin; so it can produce the same light as sunlight therapy. For human eyes, the color is only clear in sunlight, which makes the diagnosis more accurate and does not cause the eyestrain of medical staff due to long working hours.
No shadowsrequirements
Through polygonal reflectors, shadowless lamps can meet shadowless lighting requirements. This reflection is involved by computer and formed by industrial stamping at one time, and the reflectivity is as high as 95%. His shape is peculiar: it consists of many reflective surfaces that reflect light and illuminate the entire operating area. As a result, many light and shadows are superimposed to form an absolutely homogenous beam of light. The operation is carried out in this light column, that is, the light column formed from 80cm below the lamp plate and reaching the surgical area is carried out.
Thanks to the perfect design of the reflective surface and the large size of the light-reflecting surface, this co-light beam is not only as bright as sunlight but also without shadows. And while the surgeon’s shoulders, hands or head block some of the light source, it remains very uniform.
