Dual Bulb Won't Leave Surgeons in the Dark

When are two lights better than one?

Lisa Zyga is a science writer who is interested in many areas of science and technology, including the impact of science on society. She is excited about exploring new inventions in science, medicine, and space, and inspiring and fascinating readers interested in the creative frontier of science with the readers of AmericanInventorSpot.com. Here's her article:

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Wolf-Dieter Keppel from DK Engineering has found a solution to the question of when to replace a light bulb-that is, the bulb that provides light during minimally invasive surgeries, such as the for the endoscope stuck down your throat.

Currently, the $500 xenon bulb in an endoscope is replaced after a certain number of hours, even though it may have many hours of life left. This premature replacement can cost a lot of money over time.

On the other hand, sometimes an abnormally short-lived bulb can go out in the middle of a surgery. One thing that doctors don't need is added stress due to their work environment suddenly going black.

Keppel's solution is simple: replace the light bulb only after it goes out, and don't worry when it dies in the middle of inspecting a patient's dark spaces.

Why? Because Keppel has designed an apparatus that holds two light bulbs. When the original bulb goes out, the back-up goes on near-instantaneously.

Currently, a failure in the light supply during a surgery requires someone to manually plug in the fiber light cable into a spare light source, interrupting the surgical procedure for at least several seconds.

In this invention, electronic sensor circuitry can detect missing current when the first light bulb fails, which then immediately activates the second bulb.


Although this seems like a simple solution, aligning two bulbs to adequately illuminate those tiny spaces inside the body is an optical challenge. Keppel used an extended mirror, convex lens, and beam steering wedge prism to focus each bulb on the desired area.

For those who may ever have to endure an endoscope down the throat, you can feel a little more secure when you notice this dual light bulb apparatus hovering above you as you wait in the chair. When the lights go out for you, your surgeon won't be left in the dark.

Lisa ZYga
Guest Blogger

Photo credit: Wolf-Dieter Keppel, Inventor.