Friday, September 30, 2005
Philips recently developed an electric lens that changes focus as a current alters the surface-tension curves of two different liquids. But it only works for very small diameters. Now the University of Central Florida
in Orlando is claiming a way to make electric lenses of any size ? and cheaply too.
First, the curved surface of a fixed-focus lens is coated with transparent indium-tin-oxide to make a concave or convex electrode. The flat surface of a plain, transparent plate is similarly coated. The space between the two plates is then filled with nematic liquid crystal material.
When a voltage is applied across the sandwich, the curved shape of the lens electrode creates an electric field that varies in strength from centre to edge. This creates a matching gradient of refractive index in the liquid crystal. Changing the voltage changes the gradient, and thus the focal length of the sandwich lens.
The basic design can be scaled to any size, says the patent. The cost could be further reduced by making both electrodes flat plates and putting ridges on one to make it a Fresnel lens. Finally, If one electrode is reflective, it makes an electrically focused mirror.
Get the pdf file which tells how they make smart lenses in Orlando here
Wednesday, September 28, 2005
already makes aeroplanes and launches rockets. Now two Germans working for the US-based company have their sights set on an airship that takes off like a rocket.
The object is to create a lighter-than-air (LTA) craft that can hover at 15 kilometres or more after launching from a site much smaller than is usual for LTAs. The craft would be used for surveillance or communications.
The traditional way to launch an airship is to tether it horizontally and then cast off from both ends, so the craft lifts gracefully. But it needs a lot of room.
So Boeing fills the ship with helium while the rear is tethered with a short fixed line and the front with a much longer line that pays out as more gas is pumped into the front end. The nose rises in the air, until the craft is standing nearly vertical.
Both lines are then cast off at the same time and the airship shoots up like a rocket, at around 5 metres a second.
As the ship rises, a valve at the rear vents air, and the helium at the top expands - due to the lower atmospheric pressure at altitude - to fill the entire ship. This brings the blimp horizontal, enabling it to hover.
Read about Boeing?s rocket blimp here
Monday, September 26, 2005
When background noise is horribly loud - in a tank, on an airport runway or aircraft carrier - ordinary microphones are useless. Even mics that clamp to the throat or skull are no good because the noise vibrates the sensor.
So four inventors deep in the heart of US Defence territory, in Maryland and Virginia, have come up with a mic that is clamped to a back tooth. This, they say, shields it from external vibration while still picking up speech from the jaw bone.
The team provides an example of the problems that background noise can cause. In Afghanistan, a device with an external microphone is used by soldiers to automatically translate English battlespeak into the local language, Dari. But background noise can lead to misinterpretation.
In the new device, a vibration sensor is set in resin and moulded to fit like a dental cap or plate. A low-power radio link transmits audio to a higher-power transmitter built into ear-muff headphones, so wearers hear their own voice as it is sent to others.
A push-to-talk function is provided by a tongue-operated switch. The inventors say the system works in noise up to 160 decibels, which is louder than a jet aeroplane taking off. They also note that the mic works inside gas masks and that encryption can be added for security. The mic can be removed for cleaning to avoid infection.
Read all about the noise-busting tooth mic here
Friday, September 23, 2005
There is an easy way to collect traffic information for car navigation systems without the need to install a multitude of roadside cameras, says Edward Nortrup of Massachusetts, US. Just get cars with navigation systems to automatically send data to a control centre via GPRS or 3G.
Each brief call sends the time and car?s map position, as detected by the GPS receiver in the navigation system. The control centre calculates how long it takes the car to travel between logged positions. Comparing data from several cars in the same area, builds an overall pattern of traffic speed and flow. This data is then fed back to the cars to show road conditions on chosen routes.
How can drivers be persuaded to set up their phones to make the data calls? One way, says Nortrup, is to offer a subscription cost for traffic information that undercuts camera-based systems.
Another is to offer free ?how to get there? instructions, for example in adverts for a shop. The advertiser gives an automated number to call and the caller gets back a text message with road directions, or data that points the navigation system to the shop. The called number passes the time and position data to the control centre for use in traffic monitoring.
Read the full traffic information patent here
Wednesday, September 21, 2005
Using a beam of inaudible ultrasound as a carrier for audible sound has been on the drawing board for a while, but has yet to find a compelling application. But now Seiko Epson
of Tokyo, Japan, proposes using the technique to let a small video projector beam pictures and sounds into a room, without the need for loudspeakers.
Speech or music is amplitude-modulated on ultrasound at over 40 kilohertz ? rather like the way that Medium and Long Wave radio waves carry AM radio. Only a small transducer, a few centimetres wide, is needed to beam the AM ultrasound from the front of the projector. The beam bounces off the screen and back into the room and only those in the beam?s line of fire hear the sound - perfect for keeping sensitive neighbours happy.
Before the show, the projector is put in a test mode that displays a picture on screen which shows where the chairs should be put so people can hear the sound. The listening area can be modified by altering the distance and angle of the ultrasound beam to the screen, while using two beams creates stereo sound.
Read the sound projector patent here
Monday, September 19, 2005
The two divers left for 6 hours in shark-invested waters near Australia's Great Barrier Reef this week would surely have welcomed the wetsuit being patented by Vladimir Vlad in the US.
The new suit takes advantage of the fact that sharks have sensitive receptors
in their snouts which detect electrical fields in the water. This helps them track prey, but if the field is too powerful the shark backs off.
Made of metal and neoprene in the usual way, the wetsuit has thin piezoelectric ceramic fibres woven into its fabric. The fibres extend along the body and limbs, connecting to metal electrodes which harvest any charge generated when the piezo material is deformed by the wearer?s movement.
The voltage delivered by the fibres depends on their length and how many there are. During normal swimming, the suit continually generates several volts which flow through the water between the electrodes to create a deterrent field. If the diver sees an undeterred shark and swims fast to get away ? a natural reaction, one suspects ? the suit generates much higher voltages and stronger fields.
If the shark still fails to get the message and bites the suit, it gets a shock in the mouth and ? hopefully ? gives up for the day.
Read the shark shock patent here
Friday, September 16, 2005
Australian inventor Kia Silverbrook is snapping at Polaroid?s heels. His company Silverbrook Research has been filing a string of patents on a new approach to instant-picture photography.
Instead of buying a Polaroid camera, plus packs of instant picture film with a built-in battery, Silverbrook will rent you a disposable digital camera with built-in memory, colour printer and battery.
When the printer runs out of paper, the camera is returned for a partial refund or a credit against a new one. The used cameras are re-cycled by clearing the memory, recharging the batteries, adding new paper and topping up the ink.
The heart of the camera is a high-quality printer, made from a four-part silicon strip etched with inkjet holes and fed by three colour ink reservoirs. A motor feeds the paper roll over the printer head, and a guillotine chops off the finished postcard-sized prints.
Because the camera lens and electronics are re-used, the manufacturer could afford to fit a 1.5 megapixel image sensor and a 1600 dpi print head. And digital image capture allows image processing, with Holly borders for Christmas shots, pumpkins for Halloween and sepia tone and hearts for wedding pictures. Say "cheesy".
Read one of the key click-and-print camera patents here
Wednesday, September 14, 2005
has a two-pronged plan to reduce the battery drain from the large, bright screens needed to show video on mobile TVs, PDAs and cellphones.
Conventional LCD screens have a mosaic of tiny red, green and blue filters, and a white backlight. The filters absorb a lot of light, so the backlight has to be drainingly bright.
The company?s first prong is to use a monochrome LCD, with no filters. The screen shows grey scale pictures, with red, green and blue organic LEDs switching on when colour is required, which Motorola says is more efficient. The screen is refreshed at three times the normal frequency and produces smooth colour motion.
The second prong is to use solar power to help charge the device. Because there are no colour filters in the LCD, 70% of ambient light passes freely through the screen and the near-transparent thin-film organic LEDs to a back-of-screen solar panel. This trickle charges the battery. What is more, waste light from the back of the LEDs - about 10% of their output - is reflected back onto the solar cell.
Read the battery-beating LCD patent here
Monday, September 12, 2005
Ever been plagued by wrong numbers or midnight calls from far-flung time zones? No problem, says SK Telecom
Instead of the caller getting a standard brrrp-brrrp tone after dialling a number, their system allows subscribers to play a personalised message back to the dialler.
The approach works for fixed or cellphone lines, and the message heard by the dialler can be the subscriber?s number, name or nickname, interspersed with normal ring-tone and the time of day at the subscriber?s end. So anyone who has mis-dialled, or called from across the world and forgotten the time difference, immediately knows to hang up.
The subscriber sets the message by accessing a PIN-protected website, and can record a brief spoken phrase or enter text which is converted into generic male or female speech.
Or the user can program in a song (even if they can't sing). A tone-deaf subscriber just types a short lyric and the server sets it to music. Lastly, companies could use the slot for a promotional message or jingle.
Read the ring-ring message patent here
Friday, September 09, 2005
Airborne radar could be an indispensable tool for the military, although conventional dishes are usually far too heavy to be lifted by blimp or balloon. Soon, however, an entirely inflatable antenna could be carried on the breeze.
Toyon Research Corporation
in California, US, is developing the unusual radar for the US Army Missile Command in Alabama, US.
The antenna is made by inflating a sphere up to 20 metres in diameter. Half of the sphere is transparent and the other half coated internally with a reflective metallic film. Once inflated, the metallic inside of the sphere takes the shape of a perfectly smooth reflector dish.
A microwave radiator mounted inside the sphere on a powered turntable then scans a beam over the dish. The beam bounces off the metal film and out through the clear part of the ball to sweep far and wide. And, because most of the antenna is made of gas, it weighs very little and can be affixed to a lighter-than-air craft.
Read the inflatable antenna patent here
Wednesday, September 07, 2005
Today's cellphones carry a wealth of personal data and can even act as mobile credit cards. But they are all too easily lost or stolen.
Fortunately, Keith Cocita of California, US, has come up with a way to prevent valuable information kept on a phone from falling into the wrong hands. If a handset disappears for any reason, the owner simply calls it up and enters a secret code. This triggers the phone to wipe its internal memory, along with the contents of its SIM card.
Such a feature could potentially be misused, of course, or the phone might just have slipped down the back of the sofa. So to prevent a needless loss of data, the phone's charging cradle maintains a full record of all personal data kept on the device while charging the battery overnight. That way, the next time the phone, or its replacement, is charged up it will automatically be loaded with all the deleted data. Simple.
Read about the phone neutraliser patent here
Monday, September 05, 2005
A bunker-busting shell that gets so hot on impact that it burns its way through concrete and steel is being developed by the US Navy's Warfare Center in Virginia.
The shell contains a mixture of aluminium polytetrafluoroethylene (PTFE) and perchlorate oxydiser, moulded together into an aerodynamic shape. To prevent the mixture from disintegrating as it travels through air at high velocity the shell is wrapped in a soft Teflon tape, which is wound tight under high tension, heated and topped with epoxy glue to prevent unravelling.
Its high-velocity impact acts as a catalyst, forcing the two chemicals together in a red hot reaction. The projectile gets so hot so fast that it should instantly burn its way through armour plating or other defences.
And the burning shell would avoid the environmental pitfalls of radioactive depleted uranium - currently the most common material used in armour-piercing shells.
Read the burning bullets patent here
Friday, September 02, 2005
Friendly fire is a contradiction in terms, but it happens in every war. So perhaps its unsurprising that defence contractor Northrop Grumman
, based in Los Angeles, US, is patenting a way to mark vehicles and buildings so that they are avoided during a precision missile strike. The technique is especially relevant as previous systems, that use radio markers, can all too easily be jammed by the enemy.
The "avoid me" targets are made from a thin sticky material. They each contain a small battery that powers a photo-diode tuned to sense light at wavelength of 1.55 micrometres, in the mid-infrared.
When a gunship or unmanned drone flies over the area, shining a laser beam at the correct frequency, the tape is activated. This causes it to send pulses to a piezo-electric crystal and distort a reflective material on top of the tag. As the mirror distorts, it modulates the laser beam reflected back to the plane above, informing the pilot of its whereabouts.
The reflected beam can even trigger a "don?t shoot!" audio message that the pilot hears through a headset. And, because the plane is flying low and the interrogating laser is fairly powerful, the beam has a good chance of cutting through ground dust and smoke.
Read the "don't shoot" patent here