Patent ID: 9107265
Filing Date: 2015-08-11
Classification: G09G,H05B

Abstract:
1. A light emitting device array billboard, comprising: a light emitting device array including a plurality of light emitting devices arranged by a plurality of lines and a plurality of channels, wherein in each line, a forward end of each light emitting device is coupled to a common line node, and in each channel, a reverse end of each light emitting device is coupled to a common channel node; a plurality of line switch circuits respectively coupled to the corresponding line nodes, for electrically connecting the corresponding line nodes to a conduction voltage or a discharge path according to a line operation signal; a plurality of channel switch circuits each of which includes a corresponding current source, the channel switch circuits being respectively coupled to the corresponding channel nodes, for electrically connecting selected ones of the channel nodes to corresponding current sources according to a channel operation signal; a plurality of ghost image compensation switch circuits respectively coupled to the corresponding channel nodes, for electrically connecting selected ones of the channel nodes to a ghost image compensation voltage according to a ghost image compensation signal; and a control circuit coupled to the line switch circuits, the channel switch circuits and the ghost image compensation switch circuits, for providing the line operation signal, the channel operation signal and the ghost image compensation signal; wherein the control circuit provides the line operation signal and the channel operation signal to respectively control the line switch circuits and the channel switch circuits such that a selected one of the light emitting devices is turned ON for a duty period within a lighting period, and the control circuit provides the ghost image compensation signal to control the ghost image compensation switch circuits such that the channel node corresponding to the selected one of the light emitting devices is electrically connected to the ghost image compensation voltage when the selected one of the light emitting devices is not conductive after the lighting period; and wherein the control circuit further adjusts the channel operation signal according to a gray scale compensation signal such that the selected one of the light emitting devices is turned ON for a gray scale compensation period in addition to the duty period.