GM Dives into Deep Purple for Revolutionary Self-Cleaning Touch Screens

A new General Motors patent employs UV LED emitters along with a photocatalytic coating to sanitize and disinfect touchscreens.

Displays are now popular, while physical buttons are becoming obsolete. Interacting with these displays often leads to smudges at minimum, and germ accumulation at worst, causing the screens to appear unappealing and possibly hazardous—particularly in communal vehicles. Enter science to save the day! We have explored multiple methods for disinfecting car interiors effectively. exposing them to ozone or ultraviolet light However, on Valentine's Day, GM received Patent No. US 11,579,340 B2, which is for a touchscreen capable of cleaning itself as well as disinfecting.

How It Works

This system doesn’t depend on the germicidal 254-264 nm UV-C wavelengths utilized for disinfecting water systems, hospital environments, aircraft cabins, among others (a method proposed by GHSP’s Grēnlite vehicle sterilization system based in Michigan). Rather than relying on those specific frequencies, this technology uses LED-generated ultraviolet light within the range of 365-405 nm. This triggers a photocatalytic layer coated onto touchscreens. Ordinarily, these coatings resist water; however, exposure to UV radiation—such as what occurs with ample daylight—causes them to become hydrophilic, allowing them to absorb atmospheric moisture instead. The presence of this absorbed moisture enables the catalytic substance to eliminate and destroy all types of organic matter present on the screen's surface. An analogous process is presently employed to keep solar panels clean automatically.

What's the Photocatalytic Material?

The research on the patent reveals that the coating initially consists of a metal oxide, such as anatase—an unstable crystalline structure of titanium dioxide (TiO2). Crucially, this substance needs to possess a bandgap within the ultraviolet (UV) or near-ultraviolet region of the light spectrum. Following this initial composition, the layer undergoes modification through the addition of another element—this could either be a transition metal found in the middle section of the periodic table’s D-block, or alternatively, elements like nitrogen or fluorine which aren’t metals. By incorporating these dopants into the mix, the resulting shift in the bandgap allows for activation under both natural sunlight exposure and artificial UV illumination sourced from LEDs.

Does Adding UV Light Impact Screen Resolution or Brightness?

The patent illustration indicates the UV LED emitters snuggled right in between red and green emitters directly above and below them, flanked by blue emitters to either side. The UV light is invisible to the human eye, so we shouldn't notice when they're illuminated. It's unclear, however, whether not having a visible-light emitter in those regions will affect screen resolution, brightness, etc. (Probably not).

Programmable Cleaning

The patent protects for various automatic or timed cleaning cycles, and for zoned cleaning of areas featuring frequently used button areas that need more attention. It also covers all touchscreen types (mobile, public-use screens, etc. ).

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