Patent ID: 8217867
Filing Date: 2012-07-10
Classification: G09G

Abstract:
1. A method of compensating for changes in the characteristics of transistors and electroluminescent devices in an electroluminescent display, the method comprising: providing an electroluminescent display comprising a two-dimensional array of subpixels arranged in rows and columns to form a plurality of pixels, each pixel comprising at least three subpixels of different colors, each subpixel in a pixel comprising an electroluminescent device and a drive transistor, each electroluminescent device being driven by the corresponding drive transistor in response to a drive signal; providing in each pixel a readout circuit for one of the subpixels of a specific color comprising a first readout transistor and a second readout transistor connected in series; using the readout circuit to derive a correction signal for the specific color subpixel based on the characteristics of at least one of the transistors in the specific color subpixel, or the electroluminescent device in the specific color subpixel, or both; using the correction signal to adjust the drive signals applied to the drive transistor of the specific color subpixel and the drive transistors of subpixels of the specific color in one or more different pixels; providing a respective first data line for each subpixel of the specific color in each pixel for providing the drive signals to the drive transistors to cause the electroluminescent devices to emit colored light; providing a respective second data line for each subpixel of the specific color in each pixel for receiving readout signals; providing a first voltage source and a first switch for selectively connecting the first voltage source to a respective first electrode of each drive transistor; providing a second voltage source and a second switch for selectively connecting each electroluminescent device to the second voltage source; and providing a current source and a third switch for selectively connecting the current source to the second data line.