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02 Dec 2002
The pick of this week's hottest patent applications including a method to control the chirp of a semiconductor laser.
• Title: Wavelength selectable, controllable chirp, semiconductor laser
Applicant: Novalux, US
International application number: WO 02/095883
Couple a passive cavity to the active cavity of a semiconductor laser and what happens? According to patent application WO 02/095883, chirp is reduced by the ratio of the length of the active cavity to the passive one. Manipulating the position of the output mirror in the passive cavity can also change the device's emission wavelength.
• Title: Methods and apparatuses for laser ignited engines
Applicant: Southwest Research Institute, US
International application number: WO 02/095220
Adaptive optics systems, usually deployed on telescopes to sharpen images, have found an unusual use. Application WO 02/095220 describes how such systems can be used to direct laser pulses into the combustion chamber of an internal combustion engine to ignite it. Tweaking the optics can also result in ignition at several locations during one cycle of the engine.
• Title: Method for drilling microholes using a laser beam
Applicant: Siemens Aktiengesellschaft, Germany
International application number: WO 02/096167
A way to drill holes in a dielectric layer sandwiched between two metal layers is described in application WO 02/096167. The method involves focusing the output of a solid-state laser, set at a repetition rate of 15 kHz, onto the top metal layer and rotating the beam to cut out a hole. To remove material from the dielectric layer, the laser's repetition rate is reduced and the beam is defocused. "The defocusing and revolving speed are adjusted in order to select an effective energy density that is lower than the threshold for removing the second metal layer," say the applicants.
• Title: Dual laser cutting of wafers
Applicant: Kulicke & Soffa Investments, US
International application number: WO 02/094528
A US-based firm is attempting to patent a way of cutting semiconductor wafers using two lasers emitting at different wavelengths. Traversing the first laser across the substrate leaves a pattern of scribe lines in the wafer coating. The second laser then cuts through the substrate along the scribe lines.
• Title: Semen analysis
Applicant: M.E.S. Medical Electronic Systems, US
International application number: WO 02/095375
Patent application WO 02/095375 reveals a simple and quick method for measuring the total sperm concentration (TSC) in a sample. The invention uses a pulsed light source and a photodetector to measure the optical absorbance of a sample between 800 to 1000 nm, which the authors say is proportional to the TSC. The patent also discloses a method for measuring motile sperm concentration and a way to determine the average velocity of sperm cells.
Author
Jacqueline Hewett is news reporter on Optics.org and Opto & Laser Europe magazine.
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