Patent highlights

05 Dec 2003

The pick of this week’s patent applications including a way to change the bandgap of a photonic crystal.

•  Title: Photonic crystal having a modifiable optical band gap
Applicant: Photeon Technologies GmbH, Austria
International application number: WO 03/098331
An Austrian company is trying to patent a way to alter the bandgap of a photonic crystal. According to the inventors, the photonic crystal should be made of two materials, one of which has a variable refractive index. The authors say that varying the refractive index of the material by applying an electric field, heating it, or irradiating it with a specific wavelength of light changes the optical properties of the photonic crystal.

•  Title: High-reliability group III-nitride light emitting diode
Applicant: Cree, US
International application number: WO 03/098712
Patent application WO 03/098712 describes an LED that can allegedly withstand high temperature and humidity conditions. The LED contains a group III nitride heterojunction with a p-type group III nitride contact layer; an ohmic contact and a silicon nitride passivation layer. The application also details the method used to manufacture the device.

•  Title: Dispersion shift optical fiber
Applicant: Nippon Telegraph and Telephone Corporation, Japan
International application number: WO 03/098296
NTT of Japan is trying to patent a low-loss dispersion-shifted optical fiber for light transmission around 1.55 microns. The fiber’s core comprises two regions: one containing a high-concentration of GeO₂ and the other consisting of pure SiO₂ glass. The cladding contains a honeycomb hexagonal pattern of holes that extend along the length of the fiber.

•  Title: Photoluminescence floor tile
Applicant: ND Holdings, Inc, US
International application number: WO 03/097343
If you are looking to add a bit of sparkle into your floor, then the idea described in patent application WO 03/097343 is certainly for you. The glow-in-the-dark floor tile is made by mixing a photoluminescent material into a standard tile base containing a non-transparent mineral filler. The inventors say that conventional tile-making equipment can be easily adapted to manufacture photoluminescent tiles.

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