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SCHOTT solutions no. 1/2015 > Medical Technology

Medical Technology

Brillante minis

With the Solidur™ Mini LED, SCHOTT has launched the world’s smallest hermetic and fully autoclavable LED. It can be used in medical devices as a light source to illuminate the treatment area.

Bernhard Gerl

Aphysician identifies a health problem quickly on the basis of changes in the structure or color of organs, whether it is inflamed gums, an ulcer in the intestines or a blocked artery in the heart. An important prerequisite is that color-true light shines bright enough onto the tissue to be examined. Although surgical lights are always mounted to enable flexible adjustment of their beams of light, the medical device itself or the doctor's arm often casts a disturbing shadow.

High-brightness Mini LEDs from SCHOTT offer a solution that can be installed directly into the instruments and brought directly to the treatment area. Thanks to SCHOTT’s mini LED’s small dimensions and diameter of around 2.0 mm, it is now possible to equip medical devices with light where it was not possible in the past due to design limitations or required steam sterilization in an autoclave. Of course, medical equipment that comes into contact with the human body must be sterilizable. This usually takes 5 to 20 minutes in an autoclave with saturated humidity at temperatures of around 130 °C and 2 to 3 bar ambient pressure. Semiconductor devices in conventional housings, such as plastic, would be quickly rendered unsuitable under these conditions.
Solidur™ Mini LED

Ultra-small, ultra-robust and ultra-brilliant:
Only 2 mm in diameter, the autoclavable Solidur™ Mini LED (Photo below) opens up new illumination and design possibilities in fields such as surgical endoscopy or dental technology, for example (right). Photo left: Fotolia, photo right: Thinkstock

”Our Solidur™ LED technology is based on ceramic, metal and glass and provides hermetic protection for LED chips and other optoelectronics,” explains Dr. Frank Gindele, Head of R&D for LED products at SCHOTT Electronic Packaging. This combination of inorganic materials prevents the LEDs from aging due to environmental factors. As a result, they are extremely resistant to temperature fluctuations or shocks, chemicals, corrosion and the penetration of water, even at higher pressures.

These fully autoclavable LEDs open up unprecedented possibilities for medical application developers. Because they are so effective and tiny, they can be used in conventional surgical instruments, as well as in endoscopes, intraoral cameras or otoscopes.

Of course, even in earlier times, light was brought directly to the area to be examined. ”Today, however, we generate the light directly on site and thus reduce the technical complexity significantly. In certain cases, you can even work completely without an additional external light source,” explains Dr. Gindele. Instead of a separate power supply, a battery in the handle of the instrument is now sufficient as a power source for the LEDs. By eliminating additional external components, it is not only possible to develop tools that are easier to handle, but also to significantly reduce the susceptibility to interference and the need for maintenance.

When manufacturing the Mini LEDs, glass is melted as a lens element into a metal sleeve made of steel or another metal. Then, the LED chip that is mounted on a carrier is soldered or welded to the bottom of the sleeve. The resulting housing is completely gas-tight. Thus, there is no danger that water vapor could penetrate and cause corrosion inside. Oils and other chemicals also cannot reach the sensitive electronics. The LEDs packaged in this way can withstand temperatures up to 260 °C and extreme thermal shocks. They easily withstood tests in which they were immersed alternately 15 times, first into a cold liquid at 65 °C and then a hot liquid at 150 °C. Not even 3,500 autoclave test cycles affected the function of the LEDs. The Mini LED is available as a plug-enabled system and as an SMD (Surface Mount Device). A wide range of designs and coatings such as gold, silver or nickel are possible. LEDs with different wavelengths and lens caps are also available to meet individual requirements. <
Innovative SolidurTM LED-Familie

Innovative SolidurTM LED-Family

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