24 Apr 2003
The pick of this week's patent applications including a distributed Bragg reflector laser based on quantum well intermixing.
• Title: Two-section distributed Bragg reflector laser
Applicant: DenseLight Semiconductors PTE, Singapore
International application number: WO 03/032453
Patent application WO 03/032453 describes a distributed Bragg reflector laser based on quantum well intermixing. The device is divided into two parts: a gain section and an adjacent Bragg section. The patent's authors say the interface between the sections is quantum-well intermixed, making it "substantially anti-reflecting at the wavelength of the laser." The Bragg section contains a distributed reflecting structure, which ensures the laser is singlemode.
• Title: Semiconductor light emitting element and light emitting device using this
Applicant: Matsushita Electrical Industrial, Japan
International application number: WO 03/032407
Matsushita of Japan is trying to patent a white-emitting semiconductor light source. The source comprises a near-ultraviolet LED and a layer containing four fluorescent substances. The ultraviolet light from the LED activates the fluorescent layer, which in turn emits visible light. The inventors say their combination of one blue, one yellow and two green fluorescing materials provides a high flux of white-based light.
• Title: Liquid crystal display backlight utilizing side emitting fiber optics
Applicant: Honeywell International, US
International application number: WO 03/032053
Patent application WO 03/032053 outlines a liquid-crystal display that can be read in sunlight and is also compatible with night-vision goggles. The crucial component of the display is side-emitting optical fiber that is inserted between parallel-mounted fluorescent lamps.
• Title: Solar powered narrow band radiation sensing system for detecting and reporting forest fires
Applicant: Ambient Control Systems, US
International application number: WO 03/031924
Detecting forest fires could soon be made easier thanks to the system detailed in patent application WO 03/031924. The system uses a single fixed infrared detector and a solar-powered rotating mirror. The mirror rotates allowing the sensor to look for phenomena such as forest fires over a complete 360-degree area. The authors say the device can be used either standalone or in a grid to continuously cover a wider area.
Jacqueline Hewett is news reporter on Optics.org and Opto & Laser Europe magazine.