11 Jun 2004
The pick of this week’s patent applications including an optical system that could help sort colored glass.
• Title: Apparatus and method for sorting objects by colour
Applicant: QinetiQ Ltd, UK
International application number: WO 2004/045781 An optical system that sorts objects by color is described in patent application WO 2004/045781. The applicants claim that their system could be used to automatically sort glass bottles at recycling plants. Objects are classified by measuring the degree to which they transmit white light from a source such as an LED. “This provides a simple mechanism which does not require direct detection of the input object’s color,” say the applicants.
• Title: Laser marking process
Applicant: Sun Chemical Corporation, US
International application number: WO 2004/045857
A US firm is trying to patent a way to mark the thin flexible plastic films used to wrap food. The idea involves depositing a transparent layer of a laser-sensitive material on to the wrapper. A laser is then shone on the wrapper, burning the ink and causing markings to appear. The applicants claim this approach is useful for printing “use by” or “best before” dates, which must be printed shortly after the food has been packaged. As the method is non-contact, it could also be used when the contents of the package are fragile.
• Title: Passive Q-switch laser
Applicant: ELOP Electro-Optics Industries Ltd, Israel
International application number: WO 2004/049522
Patent application WO 2004/049522 describes a passively Q-switched laser system emitting in the near infrared. The Q-switch includes a saturable absorber based on IV-VI semiconductor nanocrystals which are embedded in a polymer matrix. According to the inventors, the nanocrystals should contain lead selenide or lead sulphide. “The nanocrystals may be surface passivated, and may feature a PbSe/PbS core-shell configuration,” they claim.