Mar 28, 2001 Motorola Inc. today revealed it has invented and demonstrated a new display mechanism for color reflective liquid crystal displays (RLCD), the type of display commonly found in portable electronic products such as cell phones and PDAs.
According to researchers at Motorola Labs, electrically tunable color (ETC) has the potential to significantly improve the appearance of RLCDs by electrically tuning color brightness and contrast. RLCDs are already popular with electronics manufacturers because of their low power consumption, the Schaumburg, Ill.-based company said. Motorola (nyse: MOT) said it believes the new technology will provide the breakthrough to consumer approval for RLCD.
The ETC developed at Motorola Labs, uses an in-plane electrical field to change the color of light reflected from a cholesteric liquid crystal material between two glass plates. Company researchers said they have demonstrated all three primary colors using a single layer of cholesteric liquid crystal by changing the in-plane voltage.
"A cholesteric liquid crystal has molecules coiled like springs between the glass plates," the company said. "The distance between the successive rings of the spring determines the color of light reflected by the liquid crystal material. An electric field, applied parallel to the glass plates (in-plane), effectively untwists it causing the separation between the rings to increase. This change produces an observable color shift."
Although Motorola Labs researchers claim to have demonstrated a larger color scale than current commercial color RLCDs, they admitted the technology still requires more than 100 volts to operate, and that reducing this is the most challenging issue remaining.
Motorola plans to license this patent pending technique to LCD manufacturers over the next three years.
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