— In a standard microphone, sound waves move a diaphragm and these movements are translated into electricity. But the diaphragm's mass and resilience can easily reduce its sensitivity and add distortion to any finished recording.
David Schwartz, an inventor based in California, US, thinks a much more sensitive microphone could be built using a diaphragm made from a continuous microscopic flow of water particles and a laser that senses the way this flow responds to sound waves.
Schwartz's device will stream damp air through a tube and fire light from a laser diode on one side of the tube at a sensor positioned on the opposite side.
When sound waves enter the tube through a gap they will vibrate the droplets and the laser sensor should detect the effect optically. The watery ribbon will be very sensitive to faint sounds and introduce no distortion, Schwartz claims.
Although such a microphone would no doubt cost a lot to make, some audiophiles are already happy to spend tens of thousands of dollars on turntables that use a laser to play vinyl records. So perhaps a laser-driven microphone could prove a hit too.
Read the full gas droplet microphone patent application.
Magnetic Random Access Memory (MRAM) was developed by Honeywell and Motorola as a successor to flash memory. Now Philips has plans to make it hacker-proof.
MRAM stores data by reading and writing data magnetically to a stack of thin film layers. If, however, a hacker opens the chip, they can easily read sensitive data from the layers directly. This could be a problem if an MRAM chip is used for high-security applications, like storing passwords or cryptographic keys.
The thin-film magnets in Philips' tamper-proof chip will be wrapped in a soft metal sheet and then topped with another thin-film magnet.
While the wrapper remains intact the soft metal acts as a "keeper", gathering flux from the permanent magnet into a closed loop and keeping it away from the MRAM stack. But if someone attempts to break through the metal wrap to access the MRAM layers, the keeper becomes ineffective. Flux then breaks out and immediately erases the magnetic data stored in the MRAM chip.
The beauty of the system is that it is passive. So, disconnecting power to the chip does not keep the permanent magnet from doing its job.
Read the full self-destructing memory patent application.
The internet is great for shopping but fragile packages still have to be sent through the post, so suppliers often need a warehouse full of padded bags.
Sealed Air Corporation, based in the US, says it can save space and cut costs by stockpiling flat bags and then inflating them just before mail-out. The only tricky part is automating package inflation.
The company's bags contain a network of inflatable bubbles and tubes, all connected to a common channel along one edge of the bag. When the bag is manufactured, the network is pre-dosed with a little air, but this is spread widely throughout the bag so that it remains almost flat for storage.
Just before being mailed, the bag is passed through a device like a mangle, which squeezes the trapped air into the common channel. The same machine then pierces the puffed channel with a needle and quickly inflates the whole package. Once fully pumped, the puncture is quickly heat sealed. Consumers should also be able dispose of the bags by simply piercing the package again.
Read the full inflatable mail patent application.
For more than 30 years, Barry Fox has trawled through the world's weird and wonderful patent applications, uncovering the most exciting, bizarre or even terrifying new ideas. Read previous Invention columns, including:
Triple-standard DVD, ultimate body armour, Long-range stunner, tongue-o-vision, jellyfish injections, Flesh-burn sensor, fire-escape tubes, VoIP mangling, in-flight rearming, sense that fat, Designer speakers, throw-away parachutes, password-protected bullets, spinning touchdown, palmtop Feng Shui, Origami gadgets, mile-high showers, Hydrogen fuel balls, human cannonballs, the riot slimer, the bomb jammer, Apple's all-seeing screen, the TV-advert enforcer, the wing-sprouting drone, the drink-driver arm scanner, laser spark plugs, remote-controlled implants,the "I've been shot" gun, the snore zapper, the guitar phone, explosive-eating fungus, viper vision, exploding ink, the moody media player, the spy-diver killer, preventing in-flight interference, the inkjet-printer pen, sonic watermarks, the McDownload, hot-air plane, landmine arrows, soldiers obeying odours, coffee beer, wall-beating bugging, eyeball electronics, phone jolts, personal crash alarm, talking tooth, shark shocker, midnight call-foiler, burning bullets, a music lover's dream, magic wand for gamers, the phantom car, phone-bomb hijacking, shocking airport scans, old tyres to printer ink and eye-tracking displays.