Photodetector-based stylus system

摘要

An electronic device is configured to determine a location of a stylus with respect to a display screen dependent upon first and second timing signals. A change in state of a reference pixel cell is detected using a photodetector located in close proximity to the reference pixel cell and a change in state of a pixel cell in proximity to the stylus, in response to a stylus photodetector signal received from a photodetector of the stylus. The location of the stylus with respect to the display screen is determined from the time difference between the change in state of the reference pixel cell and the change in state of the pixel cell in proximity to the stylus.

主权项

1. An electronic device comprising:
a display screen having an array of pixel cells; a reference photodetector configured to produce a first timing signal in response to a change in state of a reference pixel cell of the array of pixel cells; and one or more processors in communication with the display screen and the reference photodetector and configured to transmit display data to the display screen via a digital interface, the one or more processors responsive to the first timing signal and to a second timing signal from a photodetector of a stylus,the one or more processors further configured to utilize the first and second timing signals to determine a location of the stylus with respect to the display screen,wherein the one or more processors are coupled the display screen via a digital interface having a latency between when the display data is supplied by the one or more processors and when the corresponding image is rendered on the display screen, andwherein the reference photodetector is fixedly coupled to the electronic device in proximity to the reference pixel cell.