06 Apr 2004
The pick of this week’s patent applications including an LED-based system that assists hair growth.
• Title: Headphone type apparatus for assisting hair growth
Applicant: Biotech Inc, Japan
International application number: WO 2004/026400
Shining 600 to 700 nm light on your scalp could help hair grow back, according to the inventors of the device described in application WO 2004/026400. Resembling a set of headphones, the device contains an array of LEDs that irradiates the scalp with an intensity of 1500 to 5000 milli candela. The LEDs are pulsed at a repetition rate of 1 to 1.3 kHz.
• Title: High power semiconductor laser diode and method for making such a diode
Applicant: Bookham Technology plc, UK
International application number: WO 2004/027951
Bookham is trying to a patent a design which it says improves the stability and reduces the degradation seen in high-power laser diodes. Specifically, the authors say that their design suppresses any undesired first and higher order modes in the output of a ridge waveguide diode laser. According to the authors, the secret is to use specifically-shaped complex index guiding (CIG) elements. These contain a layer which absorbs the undesired modes and an insulating layer as a first contact to the semiconductor.
• Title: Semiconductor crystal of group III-V compound
Applicant: Mitsubishi Chemical Corporation, Japan
International application number: WO 2004/027126
A carbon-doped III-V crystal is the subject of patent application WO 2004/027126. The crystal should have a carbon concentration of 1 x 1016cm-3 or greater and an oxygen concentration of 1 x 1018cm-3 or less. The authors claim that a semiconductor laser using such a crystal has excellent high-speed modulation characteristics.
• Title: Railway obstacle detection system and method
Applicant: Rosemount Aerospace Inc, US
International application number: WO 2004/026660
A US firm is trying to patent a system which it says detects objects on a railway track and determines if they are a threat to the train. The instrument scans a laser beam over the track in a predetermined pattern and a detector gathers the reflections. The system works out where on the track the reflections have come from and produces an image of the scene ahead of the train.