User interface responsiveness in an electronic device having a touch screen display

摘要

An electronic device with a touch screen display that includes capacitive sensing to determine the point of contact between the display and an input device. The device also includes a graphics circuit for rendering images on the touch screen display. The graphics circuit may be inactivated when not in use. The inactive mode provides a variety of advantages, such as a lower power drain on the power source. The device is further configured to sense the approach of an input device in proximity to the display. The device is configured to start activating the graphics circuit upon sensing the approach of the input device prior to contact with the display. The timing of the activation improves responsiveness of the electronic device.

主权项

1. A method of operating an electronic device that includes a capacitive touch screen display, comprising:
sending image signals from a control circuit to a graphics circuit and rendering images on a touch screen display; placing the graphics circuit that renders the images to the touch screen display in an inactive mode while the control circuit that inactivated and that controls the graphics circuit and the touch screen display remains in an active mode, the graphics circuit configured to render an image in the inactive mode with a reduced rendering ability; while the graphics circuit is in the inactive mode, sensing a user input device in a capacitive field of the touch screen prior to the input device contacting the touch screen while the control circuit remains in the active mode; and in response to sensing the user input device within the capacitive field, activating the graphics circuit; while the graphics circuit is active, estimating a point of contact on the touch screen display; rendering a first image on the touch screen display corresponding to the estimated point of contact; determining an actual initial point of contact on the touch screen display, the actual initial point of contact being the point where the touch screen display is initially contacted by the user; and maintaining the first image on the touch screen display when the actual initial point of contact is the same as the estimated point of contact, otherwise when the actual initial point of contact is different than the estimated point of contact rendering a second image on the touch screen display corresponding to the actual initial point of contact, the second image being a new image corresponding the actual initial point of contact.