Touch detection for a digitizer
A detector for providing position detection of objects over a sensor with a first and second set of conductor lines forming a grid with a plurality of junctions there between at which the conductor lines do not contact, includes a signal generator providing a signal to at least one conductor line of the first set of conductor lines, and circuitry detecting output arising from one or both of an electromagnetic stylus and one or more fingers when present. The output arising from each of the one or more fingers is detected from at least one conductor line of the second set of conductor lines in response to the signal provided to the at least one conductor line of the first set of conductor lines. The circuitry detects positions of one or both the electromagnetic stylus and each of the one or more fingers when present responsive to the output detected.
1. A method for operating an on-screen keyboard, the method comprising:
providing a transparent arrangement of sensing conductors located on an electronic display screen for detecting one or more finger touches when present, the transparent arrangement including a first and second set of conductor lines forming a grid across the electronic display screen with a plurality of junctions there between at which the conductor lines do not contact;
providing a signal to a plurality of conductor lines of the first set of conductor lines;
detecting output arising from one or more finger touches when present,
wherein the output arising from each of the one or more finger touches is detected from at least one conductor line of the second set of conductor lines in response to the signal provided to the at least one conductor line of the first set of conductor lines;
detecting positions of the one or more finger touches on the transparent arrangement responsive to the output detected; and
associating the positions of the one or more finger touches on the transparent arrangement to positions of one or more keys of a keyboard displayed on the electronic display screen.
2. The method of claim 1 , comprising detecting positions of simultaneous finger touches on the transparent arrangement responsive to the output detected.
3. The method of claim 1 , comprising interpolating output detected over a plurality of conductor lines to increase accuracy of the position detection beyond the granularity of the transparent arrangement of sensing conductors.
4. The method of claim 1 , comprising detecting output arising from an electromagnetic stylus when present, wherein the output arising from an electromagnetic stylus is detected from at least one conductor line of the first or second set of conductor lines.
5. The method of claim 4 , wherein the output arising from the electromagnetic stylus and the one or more finger touches is detected from same conductor lines.
6. The method of claim 4 , wherein position of the electromagnetic stylus and positions of the one or more finger touches are detected independently.
7. The method of claim 4 , wherein position of the electromagnetic stylus and positions of the one or more finger touches are detected at different times.
8. The method of claim 4 , comprising detecting output also from the first set of conductor lines.
9. The method of claim 4 , comprising detecting output from first and second set of conductor lines simultaneously.
10. The method of claim 4 , comprising providing a signal for exciting circuitry in the electromagnetic stylus.
11. The method of claim 4 , wherein the signal for exciting circuitry in the electromagnetic stylus is applied to at least one conductor line of the first or second set of conductor lines.
12. The method of claim 1 , comprising providing the signal to the plurality of conductor lines, one at a time.
13. The method of claim 1 , comprising switching from providing the signal to the first set of conductor lines and detecting output from at least one conductor line of the second set of conductor lines to providing the signal to the second set of conductor lines and detecting output from at least one conductor line of the first set of conductor lines.
14. The method of claim 1 , comprising detecting output in the second set of conductor lines, in response to each signal applied to the plurality of conductor lines in the first set of conductor lines.
15. The method of claim 1 , wherein the signal provided is an oscillating signal.
16. The method of claim 15 , wherein the signal is configured to oscillate with respect to a reference voltage level, thereby to permit a capacitive current flow between each of the one or more finger touches and at least one conductor line from the first and second set of conductor lines.
17. The method of claim 1 , comprising detecting an oscillating signal transferred via the junctions to conductor lines in the second set of conductor lines, the transference being indicative of capacitive coupling change induced by positioning of the one or more finger touches over the transparent arrangement at the respective junctions.
18. The method of claim 1 , comprising determining a tabulation of signal values detected at each junction while the one or more finger touches are removed from the sensor.
19. The method of claim 18 , comprising correcting readings at each conductor responsive to the tabulation of signal values.
20. The method of claim 19 , comprising updating the tabulation upon startup the position detection.