Patent ID: 7456812

Claim:
Display element driver circuitry for driving an element of an electro-optic display, the circuitry having first and second control lines and a data line, the circuitry comprising: a driver to drive the electro-optic display element in accordance with a drive voltage; a photosensitive device optically coupled to the electro-optic display element to pass a current dependent upon illumination reaching the photosensitive device; a first control device coupled between the photosensitive device and the data line and responsive to a first control signal on the first control line to couple the photosensitive device to the data line; and a second control device coupled to provide a switchable current path between the photosensitive device and the driver and responsive to a second control signal on the second control line to couple the photosensitive device to the driver to provide a current path therebetween.