For over 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. His column, Invention, is exclusively online. Scroll down for a roundup of previous Invention articles.

The advert enforcer

If a new idea from Philips catches on, the company may not be very popular with TV viewers. The company's labs in Eindhoven, The Netherlands, has been cooking up a way to stop people changing channels to avoid adverts or fast forwarding through ads they have recorded along with their target programme.

The secret, according to a new patent filing, is to take advantage of Multimedia Home Platform - the technology behind interactive television in many countries around the world. MHP software now comes built into most modern digital TV receivers and recorders. It looks for digital flags buried in a broadcast, and displays messages on screen that let the viewer call up extra features, such as additional footage or information about a programme.

Philips suggests adding flags to commercial breaks to stop a viewer from changing channels until the adverts are over. The flags could also be recognised by digital video recorders, which would then disable the fast forward control while the ads are playing.

Philips' patent acknowledges that this may be "greatly resented by viewers" who could initially think their equipment has gone wrong. So it suggests the new system could throw up a warning on screen when it is enforcing advert viewing. The patent also suggests that the system could offer viewers the chance to pay a fee interactively to go back to skipping adverts.

Read the full patent here.

Micro electrical generator

There is little point in building tiny micro-electro-mechanical devices (MEMS) if they need big batteries to work. So Washington State University, US, has been working on a radical solution - a microscopic generator that burns hydrocarbon fuel to generate electricity.

Within the device, droplets of fuel are deposited onto a flat metal plate (about 1 millimetre to a side) and then ignited. As the plate heats up, drops of liquid mercury travel along a connected tube to a strip of piezoelectric material. Heat from the mercury causes the piezoelectric strip to flex, generating a small pulse of electric power.

Some of this power is used to create an electrostatic charge which moves the mercury droplets back towards the hot plate to pick up another dose of heat. This lets the system generate a continuous series of electric pulses.

Each micro-generator can only produce about 1 milliwatt of power but an array of several thousand could produce several watts - enough to let MEMS do plenty of useful work.

Read the full patent here.

Radio clotting

Major surgery can release a deluge of blood that often flows too fast to clot. If the flow is not staunched in time, this can prevent doctors from seeing what they are doing and may lead to dangerous blood loss.

A team of medics in Wisconsin, working for the US National Institutes of Health, is patenting a drastic solution. A bleeding organ could be "sewn up" by hitting it with a dose of energy along a stitch line, they suggest. The researchers have come up with a tool resembling a hairbrush that has an array of stainless steel "bristles" that serve as tiny electrodes.

To stop blood flowing, or seal off the good parts of an organ before a diseased part is cut away, the tool is pushed onto the tissue so that its electrodes break the surface.

Radio waves, at a frequency of around 10 kilohertz, are then generated by feeding current to the electrodes, with the signals skipping up and down the length of the device for around 5 minutes. This heats the organ tissue along a centimetre-wide track, sealing the blood vessels and preventing further bleeding. The patient would of course be anaesthetised, so they would not feel the procedure.

Read the full patent here.

Read previous Invention columns, featuring:

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.