Generating and validating pixel coordinates of a touch screen display
First Claim
1. A method of operating a touch-screen display system that includes a first resistive screen extending between a first bus bar and a second bus bar, and a second resistive screen extending between a third bus bar and a fourth bus bar, wherein the first resistive screen overlaps the second resistive screen to define an active area of the touch-screen display, the method comprising:
- during a first period and during a second period, touching the first resistive screen to the second resistive screen in the active area of the touch-screen display, wherein the first period and the second period are two distinct periods;
during the first period, applying a first voltage reference signal to the first bus bar;
during the first period, creating a first ground reference at the second bus bar such that the first voltage signal and the first ground reference creates a first varying voltage potential across the first resistive screen during the first period;
during the first period, sampling the first varying voltage potential via at least one of the third bus bar and the fourth bus bar;
determining an Xraw value based upon sampling the first varying voltage potential;
during the second period, applying a second voltage reference signal to the third bus bar;
during the second period, creating a second ground reference at the fourth bus bar such that the second voltage signal and the second ground reference creates a second varying voltage potential across the second resistive screen daring the second period;
during the second period, sampling the second varying voltage potential via at least one of the first bus bar and the second bus bar; and
determining a Yraw value based upon sampling the second varying voltage potential.
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Abstract
An enhanced touch-screen display system is disclosed for generating pixel coordinate estimates corresponding to a location on a display screen touched by a user. The system is an analog resistive touch-screen display system having a processor and associated software algorithms to allow for the calibration and validation of pixel coordinate estimates as an integral part of the real-time generation of the pixel coordinate estimates. Multiple calibrated pixel coordinate estimates are generated and processed at a pre-defined sampling rate to determine a valid pixel position to minimize sampling delays due to settling times. The x-axis position is also validated before the system attempts to generate a y-axis position to avoid the wasted time for generating y-axis estimates when x-axis estimates are corrupted. Noisy estimates are inherently reduced in the touch-screen display system by providing shunts across certain drivers in the system that also allow for detection of a “no touch” state.
27 Citations
9 Claims
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1. A method of operating a touch-screen display system that includes a first resistive screen extending between a first bus bar and a second bus bar, and a second resistive screen extending between a third bus bar and a fourth bus bar, wherein the first resistive screen overlaps the second resistive screen to define an active area of the touch-screen display, the method comprising:
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during a first period and during a second period, touching the first resistive screen to the second resistive screen in the active area of the touch-screen display, wherein the first period and the second period are two distinct periods; during the first period, applying a first voltage reference signal to the first bus bar; during the first period, creating a first ground reference at the second bus bar such that the first voltage signal and the first ground reference creates a first varying voltage potential across the first resistive screen during the first period; during the first period, sampling the first varying voltage potential via at least one of the third bus bar and the fourth bus bar; determining an Xraw value based upon sampling the first varying voltage potential; during the second period, applying a second voltage reference signal to the third bus bar; during the second period, creating a second ground reference at the fourth bus bar such that the second voltage signal and the second ground reference creates a second varying voltage potential across the second resistive screen daring the second period; during the second period, sampling the second varying voltage potential via at least one of the first bus bar and the second bus bar; and determining a Yraw value based upon sampling the second varying voltage potential. - View Dependent Claims (2, 3, 4, 5)
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6. A method of operating a touch-screen display system that includes a first resistive screen extending between a first bus bar and a second bus bar, and a second resistive screen extending between a third bus bar and a fourth bus bar, wherein the first resistive screen overlaps the second resistive screen to define an active area of the touch-screen display, the method comprising:
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during a first period and during a second period, touching the first resistive screen to the second resistive screen in the active area of the touch-screen display, wherein the first period and the second period are two distinct periods; during the first period, applying a first voltage reference signal to the first bus bar; during the first period, creating a first ground reference at the second bus bar such that the first voltage signal and the first ground reference creates a first varying voltage potential across the first resistive screen during the first period; during the first period, sampling the first varying voltage potential via at least one of the third bus bar and the fourth bus bar; determining an Xraw value based upon sampling the first varying voltage potential; determining an Xmax value based on the first voltage reference signal; determining an Xmin value based on the first ground reference; determining an X-pixel location based on the Xraw value, the Xmin value, and the Xmax value; during the second period, applying a second voltage reference signal to the third bus bar; during the second period, creating a second ground reference at the fourth bus bar such that the second voltage signal and the second ground reference creates a second varying voltage potential across the second resistive screen during the second period; during the second period, sampling the second varying voltage potential via at least one of the first bus bar and the second bus bar; determining a Yraw value based upon sampling the second varying voltage potential; determining a Ymax value based on the second voltage reference signal; determining a Y-min value based on the second ground reference; and determining a Y-pixel location based on the Yraw value, the Ymin value, and the Ymax value. - View Dependent Claims (7, 8, 9)
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Specification