Patent attributes
The present invention uses different frequencies to drive the LED strips in the back-lighting source so that the spatial uniformity of the back-lighting source as well as the color levels in the source can be monitored and adjusted. Each individual strip is assigned to a different frequency. Alternatively, the strips are divided into groups and each group is assigned to a different frequency. A group may comprise two or more strips. Furthermore, some groups may have more strips than the other groups and the number of LEDs in one strip may be different from the number in other strips. The brightness uniformity and the color levels in the back-lighting source are sensed by one or more groups of color sensors in R, G and B. The assignment of driving frequencies can be based on the location of the strips.