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.

Apple's all-seeing screen

We could soon see a new kind of display screen from computer maker Apple – one that simultaneously takes pictures while showing images.

The clever idea is to insert thousands of microscopic image sensors in-between the liquid crystal display cells in the screen. Each sensor captures its own small image, but software stitches these together to create a single, larger picture.

A large LCD screen filled with image sensors would be ideal for videoconferencing, Apple suggests, as participants would always appear to look straight into the "camera". The technique could also add a camera function to a cellphone or PDA without wasting space, and light from the screen should help illuminate a subject.

The more sensors there are, the wider and clearer the image. Sketches accompanying the company's patent show as many sensors as liquid crystal cells in a screen. If some of the sensors have different focal lengths, switching between them would make the screen behave like a zoom lens.

Read the full patent, here.

Red-eye age checker

This could be bad news for under-age drinkers and anyone else trying to lie about their age.

Camera maker Kodak is adapting the technology used to automatically correct flash-induced "red-eye" in digital images to determine a person's age. A patent filed by researchers from the company's labs in Rochester, New York, suggests the technique could provide a quick and easy way to check someone's date of birth.

Red-eye is the effect seen when a person's open pupils allow a camera's flash light to be reflected off their retinas. Red eye correction software analyses a picture, looking for a pair of red dots in the centre of a face, and automatically dulls them to remove the effect.

Kodak's patent mentions previous research suggesting a correlation between age and the way pupils react to light. As a person gets older, their pupils have greater difficulty widening to cope with dim light, it says.

The company suggests that an age-verification system could take mug shots of a person from a set distance in controlled lighting, using a flash. Software would then measure the size of their red-eye dots to determine how wide their pupils are and make an estimate of their age.

Although the patent doesn't say how accurate the system could be it suggests that accuracy could be boosted by automatically looking for wrinkles and grey hair in an image as well. Well, just don't point that thing at me…

Read the full patent, here.

Microwave breast scanner

Researchers from the US National Institutes of Health are working on a safer early-warning system for breast cancer.

The new system would use broadcast frequency radiation instead of X-rays to detect tumours, allowing women to undergo frequent checks without exposure to hazardous ionising radiation.

An array of up to a hundred mini-antennae would be built into a soft, breast-shaped sensing device. Each antenna would emit a very short burst of microwave energy, rapidly scanning across several frequencies, at just one-hundredth of the power output of an ordinary cellphone.

Malignant tissue is far less conductive that normal flesh, and so should reflect much more signal back to detectors built into the same device. Software would remove random reflections from the skin surface and the patent claims that tumours as small as 1 millimetre across would show up using the scanner.

Although the power is low and safe, the signal should be able to penetrate 10 cm of tissue, to reveal deeply hidden menaces. The scan should also take just one-tenth of second.

Read the full patent, here.