Scientists create eyeglasses that become shaded 'on command'

Date: Feb-05-2015 The idea of transitional lenses - that can be clear or shaded depending on the

intensity of surrounding light - is a useful one, but many users find they do not suit

their needs. Now, scientists are working on a lens material that can change from clear to

shaded and back again in seconds - when the user commands it.

The electrochromic polymer lens changes from shaded to clear - on user command - in seconds.
Image credit: American Chemical Society

The new eyeglass material is being developed by a team led by John Reynolds, professor

of chemistry & biochemistry, materials science & engineering at the Georgia Institute of

Technology in Atlanta.

The team is working on the new material in collaboration with the German technology company

BASF.

The material changes color, from clear to shaded, in response to a change in

electrical charge, which the team says could be controlled by the user - for instance, by

means of a switch.

They report their progress so far in the journal ACS Applied Materials &

Interfaces.

The researchers say many of the transitional lenses currently available - which change

in response to the brightness of surrounding light - do not always perform in the way

users want them to.

For example, they do not block out very harsh light, such as that from snow, or the

glare from strip-lighting in grocery stores.

Also, the transition time from clear to color can take several minutes with current

lenses. This can be annoying - and potentially hazardous - for people who need a much

faster response.

The team believes their new, fast-changing material could be very useful for

airline pilots and security guards.

Another common dissatisfaction with current transition lenses is they do not always

change when you need them to. For example, if you are wearing a baseball cap or driving a

car, the lenses stay clear, even in bright sunlight.

New lens material changes from shaded to clear in seconds

The new lens material the team has created is a blend of electrochromic polymers

(ECPs) that they say can be incorporated as the active material in user-controlled

electrochromic eyewear.

The authors note how, through "predictive color mixing" of ECPs in a "subtractive

fashion," they created various hues of brown by mixing "cyan and yellow primaries in

combination with orange and periwinkle-blue secondary colors."

In lab tests, all the color blends showed an ability to change from shaded

(10% transmittance of light) to clear (70% transmittance) in a few seconds.

To make the lenses, the team used a combination of inkjet printing and blade-coating,

a process they say can easily be scaled up for manufacturing. They also say it is

possible to match the full range of hues available in commercial sunglasses:

"We demonstrate the attractiveness of these ECP blends as active materials

in electrochromic eyewear by assembling user-controlled, high-contrast, fast-switching and fully solution-processable electrochromic lenses with colorless transmissive states

and colored states that correspond to commercially available

sunglasses."

In December 2014, Medical News Today learned about another group of

scientists that is developing a groundbreaking wireless

material that could one day restore sight to damaged retinas.

In the journal Nano

Letters, they describe how the material they are working on activates brain neurons

in response to light without the use of wires to an external source of energy or

light.

Written by Catharine Paddock PhD

Courtesy: Medical News Today Note: Any medical information available in this news section is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.