04 Feb 2003
The pick of this week's patent applications, including a high-power solid-state laser amplifying system.
• Title: System for controlling the tissue temperature induced by a surgical laser
Applicant: European Surgical Systems, France
International application number: WO 03/007833
Patent application WO 03/007833 describes a two-step process to monitor the increase in tissue temperature induced by a surgical laser. The system samples and ratios at least two wavelengths emitted by the tissue both of which are greater than the laser's wavelength. The authors say the resulting figure can be used to determine the tissue temperature.
• Title: High intensity and high power solid-state laser amplifying system and method
Applicant: JMAR Research, US
International application number: WO 03/007679
A US company is patenting a four-pass optical amplifying system for solid-state lasers. A linearly polarized beam is passed through the amplifier, which is transversely pumped by laser diode arrays. "The pumping module and other optical components are provided to counteract thermal lensing effects, induced thermal birefringence effects and to achieve enhanced amplification and efficiencies," claim the authors.
• Title: Gallium nitride-based LED and a production method thereof
Applicant: Osram Opto Semiconductors, Germany
International application number: WO 03/009399
Osram Opto Semiconductors is patenting an LED with a light-emitting layer based on gallium nitride (GaN). The structure comprises a layer of n-type GaN below and a layer of p-type GaN above the light-emitting layer. The patent stresses that the n- and p-type layers have a different composition to that of the light-emitting layer.
• Title: Solid-state traffic light with predictive failure analysis
Applicant: Power Signal Technologies, US
International application number: WO 03/009647
Monitoring several operating characteristics allows a circuit to flag-up when an LED is reaching the end of its life, according to patent WO 03/009647. The system senses the output generated by an LED array and also its ambient temperature. Based on these values, the circuit calculates a time-averaged temperature. Next, the system calculates the time-averaged duty cycle value of the LED array power source. The authors say that by comparing the time-averaged temperature with the time-averaged duty cycle of the power source, they can determine when the LED will fail.
Jacqueline Hewett is news reporter on Optics.org and Opto & Laser Europe magazine.