23 Apr 2004
The pick of this week’s patent applications including a white light emitting diode.
• Title: White light emitting device
Applicant: Toyoda Gosei Co, Ltd, Japan
International application number: WO 2004/032251
Japanese firm Toyoda Gosei is trying to patent a way to make white light emitting diodes. The devices are based on a purple LED which is sealed into the package using a transparent resin. The resin contains red, green, blue and yellow-emitting phosphors. The phosphors emit a range of different wavelengths, resulting in an LED that emits white light.
• Title: Optical record carrier for use with UV laser beam
Applicant: Koninklijke Philips Electronics N.V, the Netherlands
International application number: WO 2004/032128
Philips Electronics of the Netherlands has applied to patent a disc that records information using ultraviolet light between 230 and 270 nm. The disc contains a substrate and a recording stack which is made up of an information layer sandwiched between two dielectric layers. Data are stored in the information layer in a series of marks and spaces made by the UV light in a recording material. “The recording material is an alloy comprising at least two materials from the group Ge, Sb, Te, In, Se, Bi, Ag, Sn, Pb and As,” say the inventors.
• Title: High performance vertically emitting lasers
Applicant: Quintessence Photonics Corporation, US
International application number: WO 2004/032292
Patent application WO 2004/032293 discusses an edge-emitting laser (EEL) that contains a reflective surface. The EEL’s gain and feedback layers generate a beam that travels parallel to the surface of the die. The reflective surface redirects the beam in the EEL causing it to be emitted from the top or bottom surface of die. “The reflective surface can be formed by etching a vicinally-orientated III-V semiconductor die so that the reflective extends along a (111)A crystalline plane of the die,” say the authors.
Author
Jacqueline Hewett is technology editor on Optics.org and Opto & Laser Europe magazine.
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