05 May 2005
The pick of this week's patents including an LED jacket that could make cycling safer.
• Title: Electrowetting display device
Applicant: Koninklijke Philips Electronics, The Netherlands
International application number: WO 2005/036517
European electronics giant Philips has devised an electrowetting display based on two immiscible fluids and a transparent support plate. For an oil and water system, applying a voltage between the water and support plate causes the opaque oil layer to break up or move aside, making the corresponding picture element, or pixel, transparent. Although intermediate DC voltage levels can be used to display a range of optical states, the resulting greyscale image has poor stability, according to the firm. The company's solution is to employ voltage signals that contain both a DC and AC part to avoid local spreading of the oil.
• Title: Intracavity frequency-tripled CW laser
Applicant: Coherent Inc., US
International application number: WO 2005/038999
US laser manufacturer Coherent is trying to patent a more efficient way of performing intracavity third-harmonic conversion in a continuous wave laser. By converting residual second-harmonic radiation back into its fundamental mode and reusing this radiation in the tripling process, the firm claims to be able to improve the third harmonic generating efficiency by a factor of two or more. The set-up features two nonlinear crystals and would suit semiconductor or NdYVO4 gain media.
• Title: Signalling device and item of clothing provided therewith
Applicant: Infineon Technologies AG, Germany
International application number: WO 2005/034663
Cyclists, horse riders and other road users could be interested in the signalling clothing described by German firm Infineon in patent application WO 2005/034663. The jacket features angle measuring sensors that determine the angle of the wearer's arms relative to the torso. Arm movements such as indicating a left or right turn automatically activate a series of LEDs placed around the jacket's cuff, alerting surrounding traffic to the forthcoming manoeuvre. The clothing includes a rechargeable energy source or battery pack.