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Patent highlights

15 Dec 2003

The pick of this week’s patent applications including a high-power LED and a non-unravelling seam.

•  Title: Method of forming quantum dots for extended wavelength operation
Applicant: Imperial College Innovations Limited, UK
International application number: WO 03/100833
Patent application WO 03/100833 describes a way to grow the active layer of an optoelectronic device that emits at wavelengths greater than 1350 nm. Step one involves growing a pattern of quantum dots on a substrate and then covering them with a spacer layer. “This allows a choice of growth parameters more favorable to the formation of quantum dots in the active layer emitting at long wavelength with a narrow inhomogeneous broadening,” say the application’s authors. “The quantum dots of the active layer are then subject to less intermixing with the surrounding spacer and capping layers.” They add that this method is particularly suited to growing an active region on a gallium arsenide substrate.

•  Title: High power, high luminous flux light emitting diode and method of making the same
Applicant: AXT, Inc, US
International application number: WO 03/100874
Fabricating a pair of electrodes in a specific pattern is the key to the high-power LED described in patent application WO 03/100874. One of the electrodes is shaped like a C, while the other resembles a 3. The C-shaped electrode is designed to fit around the middle bar of the 3. “This provides a configuration that enhances the current spreading along the length of the legs of both electrodes,” say the inventors.

•  Title: Method and machine for production of a non-unravelling seam
Applicant: Christian Guilheim, Jacques Guilhem, Marc Guilhem, France
International application number: WO 03/102287
If sewing up the hem on a piece of clothing is a chore you would rather avoid, then the idea being patented by three French inventors is one to look out for. The patent application describes a special thread which contains a thermoplastic material. The inventors shine an infrared laser beam onto the stitching to soften the thermoplastic material and apply pressure to the clothing to solidify the threads.

•  Title: Device and method for measuring temperature
Applicant: Leiv Eiriksson Nyskaping AS, Norway
International application number: WO 03/101288
A Norwegian company is trying to patent a way to measure the temperature of the retina in a human or an animal. The first step is to filter out the thermal contribution from the other components of the eye, leaving only a near-infrared signal from the retina. This trace is then compared to reference signal in Fourier space allowing the temperature of the retinal to be calculated.

Jacqueline Hewett is news reporter on Optics.org and Opto & Laser Europe magazine.

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