New liquid crystals prevent automobile touch screens from freezing

February 9, 2016

In addition to appearing in nearly every consumer electronic device, liquid crystal displays have recently proliferated in automobiles too, in heads-up displays, instrument cluster displays, navigation systems and entertainment displays. Due to limitations in current display technology, the images blur and the displays are slow to respond in extreme temperatures.

"When we turn on the car, we want to be certain our GPS is functioning properly and not affected by extreme winter or summer temperatures," said Shin-Tson Wu, Pegasus Professor of Optics and Photonics, University of Central Florida - College of Optics and Photonics, USA.

Wu and his colleagues from the University of Central Florida, Xi'an Modern Chemistry Research Institute in Xi'an, China, and DIC Corporation, Japan, have recently developed three new liquid crystal mixtures that overcome previous physical limitations on upper and lower operation temperatures. They report their results this week in Optical Materials Express, a journal published by The Optical Society (OSA).

According to Wu, the liquid crystals should have a clearing point higher than 100° C (or 212° F), and a melting point below -40° C (or -40° F). Beyond this range, the liquid crystal would be non-functional because it will be either frozen or isotropic.

To keep their liquid crystals operating at such a wide temperature range, the researchers mixed a dozen three-ring and four-ring compounds together with low molecular weight compounds. This type of mixture is considered a eutectic system. In addition to boosting the clearing point, the mixtures exhibit low viscoelastic coefficients and activation energies. These properties play a key role in maintaining low viscosity of the liquid crystals at low temperatures, as the response time of a liquid crystal display device is mainly governed by the viscoelastic coefficient and the liquid crystal layer thickness.

As noted in the paper, current European automotive standards require a response time for pixels to change from one brightness to another of 200 milliseconds at -20° C (or -4° F) and 300 milliseconds at -30° C (or -22° F), which are insufficiently rapid to avoid an image blur. The reported by Wu and his colleagues is about 10 milliseconds – roughly 20 times faster than the European requirements. Additionally, these mixtures enable field-sequential color display at an elevated temperature, which results in a tripling in resolution density and display brightness. This approach improves the ambient contrast ratio of heads-up displays in the daytime.

Future work for Wu and his colleagues includes developing extremely thin displays for integration with rearview mirrors to eliminate blind spots for drivers, as well as improving the readability of all types of automotive displays in harsh sunlight.

Explore further: Sony develops 'Hybrid FPA', a novel liquid crystal alignment technique for LCD

More information: Fenglin Peng et al. High performance liquid crystals for vehicle displays, Optical Materials Express (2016). DOI: 10.1364/OME.6.000717

Related Stories

Glasses-free ultrahigh-definition 2D/3D switching display

December 30, 2014

Toshiba Corporation has developed a new technology for glasses-free 3D displays that uses a low-crosstalk, high-definition LCD GRIN lens with a 15-inch 4K LCD panel. The technology realizes a highly portable, compact display ...

Aluminum nanoparticles could improve electronic displays

January 6, 2016

Whether showing off family photos on smartphones or watching TV shows on laptops, many people look at liquid crystal displays (LCDs) every day. LCDs are continually being improved, but almost all currently use color technology ...

Recommended for you

CP violation or new physics?

July 25, 2016

(Phys.org)—Over the past few years, multiple neutrino experiments have detected hints for leptonic charge parity (CP) violation—a finding that could help explain why the universe is made of matter and not antimatter. ...

Building a Moebius strip of good vibrations

July 25, 2016

Yale physicists have created something similar to a Moebius strip of moving energy between two vibrating objects, opening the door to novel forms of control over waves in acoustics, laser optics, and quantum mechanics.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.