Patent highlights

06 May 2003

This week's patent highlights includes a Q-switching method that produces a train of pulses all with the same peak power.

•  Title: Q-switching method for pulse train generation
Applicant: Coherent, US
International application number: WO 03/036769
Laser giant Coherent is trying to patent a Q-switching method that produces a train of pulses all with the same peak power. The laser contains a solid-state gain medium that exhibits a thermal-lensing effect when it is optically pumped. When the laser is operating in continuous wave mode (CW), an internal Q-switch remains open. "A train of pulses is delivered by repeatedly interrupting the CW operation by closing then reopening the Q-switch," say the authors. They claim that this method ensures the thermal-lensing effect in the gain-medium remains constant before, during and between emission of the pulse trains.

•  Title: Solid-state continuous sealed clean room light fixture
Applicant: TIR Systems, Canada
International application number: WO 03/036159
A Canadian company is trying to patent an LED-based clean room light source. The sealed source uses several components to efficiently direct light downwards into the room. These include high-refractive index reflectors coupled to each LED; a refractive-index matching compound applied between each LED-reflector pair; and anti-reflection coatings on the LEDs and reflectors. The authors say that a holographic diffusion lens and/or a variable transmission filter can be provided to distribute the light uniformly.

•  Title: Identification of material inclusions in pulp and paper using Raman spectroscopy
Applicant: Stora Enso North America, US
International application number: WO 03/036271
Patent application WO 03/036271 describes how Raman spectroscopy can be used to identify paper quality. The method generates spectroscopic images of all or selected constituents and/or contaminants in a sample and uses a reference library to identify them. The authors of the patent say this helps control the paper-making process as well as monitor the quality of the paper that is produced.

•  Title: Circuit formation by laser ablation of ink
Applicant: Sigtronics, UK
International application number: WO 03/037049
Patent application WO 03/037049 describes a way to form conductive tracks on the substrates used to make printed circuit boards. The first step is to coat the alumina-based substrate with conductive ink. A laser is then focused onto and translated across the substrate, ablating the ink and producing the tracks. Curing fixes the tracks in place. The patent also details a similar method of forming multiple layers of conductive tracks. In this case, a layer of cured dielectric ink separates each conductive layer.

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