08 Oct 2004
The pick of this week's patent applications including a heads-up display for a propeller-driven aircraft.
• Title: Heads-up display for propeller-driven aircraft
Applicant: SRI International, US
International application number: WO 2004/083935
A US firm is trying to patent a heads-up display (HUD) for propeller-driven light aircraft. The HUD uses a number of LEDs which are mounted on the propeller blades. A graphics generator monitors the rotation of the propeller and controls the emission of the LEDs. "Timed activation and deactivation of specific light-emitting elements on the propeller blades causes at least one high-resolution, stable imaging to appear in front of the cockpit in the plane of the propeller disk," explain the applicants. "The HUD system is lightweight and inexpensive, compared with current technology." They add that the display could show information such as the position of other aircraft and the flight path.
• Title: Electroluminescent device
Applicant: Cambridge Display Technology, UK
International application number: WO 2004/084260
Cambridge Display Technology believes it has come up with a way to improve the lifetime and efficiency of organic light-emitting diodes across a range of colors. "The combination of a cathode comprising a relatively high work-function such as barium and a hole-transporting and electron-blocking material deposited between the anode and the organic semiconductor layer results in the improvement," say the authors.
• Title: High power semiconductor laser with a large optic superlattice waveguide
Applicant: Bookham Technology, UK
International application number: WO 2004/084366
Coupling high-power semiconductor diodes lasers into optical fibers could become easier thanks to the design described in patent application WO 2004/084366. Bookham Technology says its invention suits pump lasers for fiber amplifiers operating at wavelengths greater than 1100 nm. The idea involves adding an optical superlattice, made up of layers with alternating indices of refraction, into the laser structure. "The superlattice is designed to produce the desired low vertical far-field by weak vertical guiding of the optical mode which results in a widened near-field mode," say the applicants. "This is due to the low average index of refraction obtained from the individual layers."