REDUCING ELECTRONIC NOISE IN A LIQUID CRYSTAL DISPLAY
Original Publication Date: 1999-Sep-01
Included in the Prior Art Database: 2002-Aug-27
There is a trend towards reducing the system voltage in portable RF communications products from 5 volts to 3.3, 2.7 and now 1.8 volts. One advantage of this trend for RF products is that as the system voltage has been reduced, the overall system noise floor has been reduced. Unfortunately, liquid crystal display (LCD) drive voltages have not been reduced as quickly as system voltages. This is because a reduction in LCD drive voltage results is unacceptable response times below 0 degrees centi- grade. Therefore, other more inventive means are required to reduce the noise level in liquid crystal displays. Several methods are reviewed for reduc- ing the EMI, RF1 and crosstalk associated with a display. The methods keep the driver supply volt- ages and duty cycle unchanged, and therefore do not impact the electro-optic performance of the display.