Sensing apparatus and associated sequential scan driving method

• US 8,416,213 B2
• Filed: 12/23/2008
• Issued: 04/09/2013
• Est. Priority Date: 05/14/2008
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Shen, Yu-Tang, Yeh, Shao-Hsing
• Primary Examiner(s): Snyder, Adam J
• Application Number:
  US12/342,258
• Publication Number:
  US 20090284398A1
• Time in Patent Office: 1,568 Days
• Field of Search: 345/174, 178/18.05, 738/620.46
• US Class Current: 345/174
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: H03K 17/002 Switching arrangements with several input- or output terminals code converters H03M5/00, H03M7/00
• CPC Class Codes: H03K 17/9618 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard

Abstract

A sensing apparatus and a scan driving method thereof are provided. The sensing apparatus includes first and second electrodes, a sensing element array, first and second electrode scan driving circuits and a control circuit. The sensing element array outputs at least one first inductive voltage after being touched. The first electrode scan driving circuit sequentially scans and drives the first electrodes, wherein the driven first electrode is set to a high level output state and the first electrode not being driven is set to a low level output state or a grounding state. The second electrode scan driving circuit sequentially scans and drives the second electrodes, wherein the driven second electrode is set to high impedance (input) state, and the second electrode not being driven is set to a low level output state or the grounding state. The control circuit controls the first and second electrode scan driving circuits.

Claims

1. A resistive sensing apparatus, comprising:

a plurality of first electrodes;

a plurality of second electrodes;

a sensing element array, disposed between the first electrodes and the second electrodes, for outputting at least one first inductive voltage after being touched;

a first electrode scan driving circuit for sequentially scanning and driving the first electrodes, wherein the first electrode being driven is set to a constant high level output state, and the first electrode not being driven is set to a constant low level output state or a grounding state;

a second electrode scan driving circuit for sequentially scanning and driving the second electrodes, wherein the second electrode being driven is set to a high impedance input state, and the second electrode not being driven is set to the constant low level output state or the grounding state; and

a control circuit for controlling scan driving methods of the first electrode scan driving circuit and the second electrode scan driving circuit, wherein the at least one first inductive voltage changes when the first and second electrodes are scanned.

2. The resistive sensing apparatus according to claim 1, wherein the sensing element array includes a plurality of sensing elements each comprising:

a resistive sensor;

a first connection point electrically connected to the resistive sensor; and

a second connection point, wherein a gap or a clearance is formed between the second connection point and the first connection point when the sensing element is not touched, and the first connection point contacts the second connection point so that the first electrode is coupled to the second electrode via the resistive sensor when the sensing element is touched.

3. The resistive sensing apparatus according to claim 1, wherein the sensing element array comprises a plurality of sensing elements each comprising:

a resistive sensor; and

a switching element, which is turned on when the sensing element is touched such that the first electrode is coupled to the second electrode via the resistive sensor.

4. The resistive sensing apparatus according to claim 3, wherein the switching element is a transistor.

5. The resistive sensing apparatus according to claim 3, wherein the switching element is a diode.

6. The resistive sensing apparatus according to claim 1, wherein the second electrodes is coupled to the control circuit.

7. The resistive sensing apparatus according to claim 1, further comprising:

a read-out circuit for measuring the first inductive voltage.

8. The resistive sensing apparatus according to claim 7, wherein the read-out circuit comprises:

a plurality of amplifiers, wherein one of the amplifiers amplifies the first inductive voltage into a second inductive voltage; and

a multiplexer for selectively outputting the second inductive voltage from the amplifiers to the control circuit.

9. The resistive sensing apparatus according to claim 7, wherein the read-out circuit comprises:

a multiplexer for selectively outputting the first inductive voltage from the second electrodes; and

an amplifier for amplifying the first inductive voltage into a second inductive voltage and outputting the second inductive voltage to the control circuit.

10. The resistive sensing apparatus according to claim 7, wherein the read-out circuit comprises:

a plurality of amplifiers, wherein one of the amplifiers amplifies the first inductive voltage into a second inductive voltage, and outputs the second inductive voltage to the control circuit.

11. The resistive sensing apparatus according to claim 7, wherein the read-out circuit is integrated in the second electrode scan driving circuit.

12. The resistive sensing apparatus according to claim 11, further comprising a switching device coupled between the second electrodes and the second electrode scan driving circuit.

13. The resistive sensing apparatus according to claim 12, wherein the switching device comprises a plurality of switches, each of which selectively electrically connects the corresponding second electrode to the second electrode scan driving circuit or a ground.

14. The resistive sensing apparatus according to claim 1, further comprising:

a buffer amplifier circuit for increasing a driving current for driving the sensing element array.

15. The resistive sensing apparatus according to claim 14, wherein the buffer amplifier circuit is integrated in the first electrode scan driving circuit.

16. The resistive sensing apparatus according to claim 14, wherein the first electrode scan driving circuit and the second electrode scan driving circuit are integrated in the control circuit.

17. A scan driving method of a resistive sensing apparatus, the method comprising:

sequentially scanning and driving a plurality of first electrodes, wherein the first electrode being driven is set to a constant high level output state, and the first electrode not being driven is set to a constant low level output state or a grounding state;

sequentially scanning and driving a plurality of second electrodes, wherein the second electrode being driven is set to a high impedance (input) state, and the second electrode not being driven is set to the constant low level output state or the grounding state; and

outputting at least one first inductive voltage when a sensing element array between the first electrodes and the second electrodes is touched, wherein the at least one first inductive voltage changes when the first and second electrodes are scanned.

18. The method according to claim 17, further comprising:

measuring the first inductive voltage.

19. The method according to claim 17, further comprising:

amplifying the first inductive voltage into a second inductive voltage.

20. The method according to claim 17, further comprising:

increasing a driving current for driving the sensing element array.