Touchscreens, Long Nails, and an Experimental Polish

Arthur T Knackerbracket writes:

The polish registers as touch by disrupting the screen's electric field:

A newly formulated nail polish could one day let people activate touchscreens with their fingernails.

When pressed to a screen, the polish disrupts the screen's electric field, which the device registers as touch. While the formula isn't commercially viable yet, it could allow people with long nails to use them like styluses.

This is huge, because it shows that functional behavior can be embedded invisibly into everyday cosmetic materials," says Shuyi Sun, a computer scientist who has studied cosmetic biosensors and now works at the Association of California Nurse Leaders in Sacramento.

Touchscreens, such as on smartphones and tablets, are typically made of glass coated with a thin, transparent layer of electrically conductive material. That layer creates a small electric field across the screen. When another conductive object, such as a fingertip, contacts the screen, it disturbs the electric field. The device registers that disturbance as a touch and can detect the point on the screen where it occurred.

But nonconductive materials - like a fingernail or the fabric of a glove - don't distort the field, so they don't register on the screen. People with long nails must use the pads of their fingers to type because they can't use their nails.

It's really hard to use your phone," says Manasi Desai, an undergraduate student studying chemistry and biology at Centenary College of Louisiana in Shreveport. Changing which part of the finger people type with can cause typing errors, at least until users adjust to the new angle.

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