CONTROL UNIT, SENSING DEVICE FOR A CAPACITIVE TOUCH PANEL AND METHOD THEREOF
First Claim
1. A sensing device for a capacitive touch panel, the capacitive touch panel being rectangular and having a transparent substrate and a sensing layer on the transparent substrate, the sensing layer being transparent and electrically conductive, the capacitive touch panel further having a first X side, a second X side, a first Y side and a second Y side, the sensing device comprising:
- a first X side switch circuit connected to the first X side;
a second X side switch circuit connected to the second X side;
a first Y side switch circuit connected to the first Y side;
a second Y side switch circuit connected to the second Y side;
a sensing source, comprising a first sensing signal source and a second sensing signal source; and
a control circuit, receiving at least one first sensing signal generated by the first sensing signal source and at least one second sensing signal generated by the second sensing signal source, the control circuit further comprising;
a first current measurement circuit, receiving a first X side current signal generated by the first X side switch circuit or a first Y side current signal generated by the first Y side switch circuit;
a second current measurement circuit, receiving a second X side current signal generated by the second X side switch circuit or a second Y side current signal generated by the second Y side switch circuit;
a first sample and hold circuit, connected to and sampling output of the first current measurement circuit;
a second sample and hold circuit, connected to and sampling output of the second current measurement circuit;
a switch, selectively connected to one of outputs of the first sample and hold circuit and the second sample and hold circuit according to the received first sensing signal or the second sensing signal; and
a control unit, comprising;
an analogue/digital conversion circuit, connected to the switch to receive a first X side analogue signal generated by the first X side current signal, a first Y side analogue signal generated by the first Y side current signal, a second X side analogue signal generated by the second X side current signal and a second Y side analogue signal generated by the second Y side current signal, and correspondingly converting them into a first X side digital signal, a second X side digital signal, a first Y side digital signal and a second Y side digital signal; and
a location determining unit, connected to the analogue/digital conversion circuit, and comprising;
an X coordinate determining device, determining X coordinate of a touch point according to the first X side digital current signal and the second X side digital current signal; and
an Y coordinate determining device, determining Y coordinate of the touch point according to the first Y side digital current signal and the second Y side digital current signal.
1 Assignment
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Accused Products
Abstract
A noise reducing device for a capacitive touch panel and a method of reducing noise for a capacitive touch panel are disclosed to solve problems related to noise generated by a conventional filter circuit and an integrating circuit or external noise. In the invention, at least one switch circuit is used so that the conventional filter circuit and integrating circuit used in the prior are omitted. Signals output from a current measurement circuit are transmitting to a control unit to calculate the location of a touch point, reducing any noise
10 Citations
31 Claims
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1. A sensing device for a capacitive touch panel, the capacitive touch panel being rectangular and having a transparent substrate and a sensing layer on the transparent substrate, the sensing layer being transparent and electrically conductive, the capacitive touch panel further having a first X side, a second X side, a first Y side and a second Y side, the sensing device comprising:
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a first X side switch circuit connected to the first X side; a second X side switch circuit connected to the second X side; a first Y side switch circuit connected to the first Y side; a second Y side switch circuit connected to the second Y side; a sensing source, comprising a first sensing signal source and a second sensing signal source; and a control circuit, receiving at least one first sensing signal generated by the first sensing signal source and at least one second sensing signal generated by the second sensing signal source, the control circuit further comprising; a first current measurement circuit, receiving a first X side current signal generated by the first X side switch circuit or a first Y side current signal generated by the first Y side switch circuit; a second current measurement circuit, receiving a second X side current signal generated by the second X side switch circuit or a second Y side current signal generated by the second Y side switch circuit; a first sample and hold circuit, connected to and sampling output of the first current measurement circuit; a second sample and hold circuit, connected to and sampling output of the second current measurement circuit; a switch, selectively connected to one of outputs of the first sample and hold circuit and the second sample and hold circuit according to the received first sensing signal or the second sensing signal; and a control unit, comprising; an analogue/digital conversion circuit, connected to the switch to receive a first X side analogue signal generated by the first X side current signal, a first Y side analogue signal generated by the first Y side current signal, a second X side analogue signal generated by the second X side current signal and a second Y side analogue signal generated by the second Y side current signal, and correspondingly converting them into a first X side digital signal, a second X side digital signal, a first Y side digital signal and a second Y side digital signal; and a location determining unit, connected to the analogue/digital conversion circuit, and comprising; an X coordinate determining device, determining X coordinate of a touch point according to the first X side digital current signal and the second X side digital current signal; and an Y coordinate determining device, determining Y coordinate of the touch point according to the first Y side digital current signal and the second Y side digital current signal.
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2. A sensing device for a capacitive touch panel, comprising:
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a sensing signal source, providing a sensing signal to a plurality of contacts of the capacitive touch panel; a plurality of connection circuits, each connection circuit connecting to at least one of the plurality of contacts; a plurality of digital synchronization circuits, each digital synchronization circuit generating a digital signal according to an analogue signal outputted from one of the connection circuits, and all of the digital synchronization circuits receive corresponding analogue signals simultaneously; and a location determining unit, calculating a coordinate of a touch point on the capacitive touch panel according to the digital signals. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A control unit of a capacitive touch panel, comprising:
a plurality of digital integration circuits, each the digital integration circuit comprising; an analogue/digital converter for converting a plurality of sampled analogue signals into a plurality of digital signals continuously when the analogue signal receives one signal source in an adder cycle; an adder for generating an integration value according to a summary of the digital signals in the adder cycle; and a coordinate calculation unit for calculating a coordinate of a touch point on the capacitive touch panel according to the integration value. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
Specification