A new color filter developed by researchers at the University of Michigan could enhance LCD efficiency by 400 percent.
Professor L. Jay Guo and his team have created an optical film that both polarizes and colors the light that passes through an LCD, which replaces the multiple layers of optical devices that traditionally played the same role. With the use of these conventional layers, an LCD would only emit eight percent of the light produced by its backlight. With the newly developed film, 36 percent of light is emitted, which is an increase that enhances overall LCD efficiency.
The new color filter consists of two thin aluminum layers enclosing a type of insulating material, and is less than 200 nanometers thick. It also contains slits that create different colors when the backlight illuminates them, and they are "matched in scale to the wavelength of visible light" and their "length and distance apart determine the color produced."
What really increases LCD efficiency is the grating pattern, which enhances efficiency by 400 percent. Instead of absorbing half the light with the wrong polarization like current LCD polarizing filters, the new filter reflects the light toward a mirror that "flips" some of its polarization and allows more light to pass through the filter.
But Guo's new filter doesn't only apply to color displays. It can also be applied to solar cells to control polarizations and reflections of light. In addition, Nicholas Fang from the University of Illinois at Urbana-Champaign noted that these filter's could be combined with Qualcomm's new low-power reflective displays to eliminate backlights altogether.
The next step, according to Guo and his team, is to find a way to mass produce these new filters and integrate them into several types of technological devices like televisions and cell phones.