CAPACITIVE SENSOR AND DETECTION METHOD USING THE SAME

• US 20120327026A1
• Filed: 09/07/2012
• Published: 12/27/2012
• Est. Priority Date: 01/07/2011
• Status: Abandoned Application

• Current Assignee: eGalax_eMPIA Technology Inc.
• Original Assignee: eGalax_eMPIA Technology Inc.
• Inventors: LEE, CHENG-HAN, TANG, CHI-HAO
• Application Number:
  US13/606,261
• Publication Number:
  US 20120327026A1
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• 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 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/047 using sets of wires, e.g. crossed wires
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2017/9602 characterised by the type or shape of the sensing electrodes

Abstract

The present invention provides a capacitive sensor and a detection method using the same. The capacitive sensor of the present invention includes a plurality of detecting plates arranged sequentially. Each detecting plate is provided with the same driving signal. According to the difference between signals of each detecting plate and another detecting plate, detecting plates touched or approached by external objects can be identified.

Claims

1. A capacitive sensor comprising:

a plurality of sequentially arranged detecting plates;

at least one reference plate disposed between the detecting plates;

a memory for storing a lookup table, wherein the lookup table defines corresponding relationships between a plurality of signal differences or amounts of change in signal difference and the detecting plate being touched/approached; and

a controller that simultaneously provides an electrical signal to each detecting plate, and provides the electrical signal or a DC potential to the reference plate, so that the signal difference or the amount of change in signal difference is generated by subtraction between signals of each detecting plate and another detecting plate, and determines if at least one detecting plate is touched or approached by at least one external object by using the lookup table based on the signal differences.

2. The capacitive sensor of claim 1, wherein the controller designates one of the detecting plates as a specific detecting plate, and each signal difference or the amount of change in signal difference is generated by subtraction between signals from one of non-specific detecting plates and the specific detecting plate.

3. The capacitive sensor of claim 1, wherein each signal difference or the amount of change in signal difference is generated by subtraction between signals from one of the detecting plates and a preceding detecting plate.

4. A capacitive sensor comprising:

a plurality of sequentially arranged detecting plates;

at least one reference plate disposed between the detecting plates; and

a controller that simultaneously provides an electrical signal to each detecting plate, and provides the electrical signal or a DC potential to the at least one reference plate, or simultaneously provides an electrical signal to each reference plate, so that a signal difference is generated by subtraction between signals from each of the detecting plate and a preceding detecting plate, and the signal differences are combined to form a plurality of continuous signal differences, and each signal difference of the continuous signal differences is added to all the preceding or following signal differences to generate a plurality of continuous recovered signal values, and it is determined whether at least one detecting plate is touched or approached by at least one external object based on the continuous recovered signal values.

5. The capacitive sensor of claim 4, wherein the continuous recovered signal values further include an additionally added zero and each of the continuous recovered signal values correspond to one of the detecting plates, respectively.

6. The capacitive sensor of claim 5, wherein a detecting plate corresponding to a recovered signal value that exceeds the smallest value among the continuous recovered signal values by a threshold is determined to be touched or approached by an external object.

7. The capacitive sensor of claim 5, wherein the controller further includes generating an average of the continuous recovered signal values, wherein a detecting plate corresponding to a recovered signal value that exceeds the average is determined to be touched or approached by an external object.

8. The capacitive sensor of claim 4, further comprising a memory for storing a lookup table, wherein the lookup table defines corresponding relationships between the continuous recovered signal values and the detecting plate being touched or approached, and the controller determines if at least one detecting plate is touched or approached by at least one external object by using the lookup table based on the continuous recovered signal values.

9. A capacitive sensor comprising:

a plurality of sequentially arranged detecting plates;

at least one reference plate disposed between the detecting plates;

a means for simultaneously providing an electrical signal to each detecting plate and providing the electrical signal or a DC potential to the reference plate, or simultaneously providing an electrical signal to each reference plate;

a means for generating a signal difference by subtraction between signals from each of the detecting plate and a preceding detecting plate and combining the signal differences to form a plurality of continuous signal differences;

a means for adding each signal difference of the continuous signal differences to all the preceding or following signal differences to generate a plurality of continuous recovered signal values; and

a means for determining if at least one detecting plate is touched or approached by at least one external object based on the continuous recovered signal values.

10. The capacitive sensor of claim 9, wherein the continuous recovered signal values further include an additionally added zero and each of the continuous recovered signal values correspond to one of the detecting plates, respectively.

11. The capacitive sensor of claim 10, wherein a detecting plate corresponding to a recovered signal value that exceeds the smallest value among the continuous recovered signal values by a threshold is determined to be touched or approached by an external object.

12. The capacitive sensor of claim 10, further comprising a means for generating an average of the continuous recovered signal values, wherein a detecting plate corresponding to a recovered signal value that exceeds the average is determined to be touched or approached by an external object.

13. The capacitive sensor of claim 9, further comprising a memory for storing a lookup table, wherein the lookup table defines corresponding relationships between the continuous recovered signal values and the detecting plate being touched or approached, and the controller determines if at least one detecting plate is touched or approached by at least one external object by using the lookup table based on the continuous recovered signal values.

14. A capacitive sensor comprising:

a plurality of sequentially arranged detecting plates; and

a controller that simultaneously provides an electrical signal to each detecting plate, so that a signal difference is generated by subtraction between signals from each of the detecting plate and a preceding detecting plate, and the signal differences are combined to form a plurality of continuous signal differences, and each signal difference of the continuous signal differences is added to all the preceding or following signal differences to generate a plurality of continuous recovered signal values, and it is determined whether at least one detecting plate is touched or approached by at least one external object based on the continuous recovered signal values.

15. The capacitive sensor of claim 14, wherein the continuous recovered signal values further include an additionally added zero and each of the continuous recovered signal values correspond to one of the detecting plates, respectively.

16. The capacitive sensor of claim 15, wherein a detecting plate corresponding to a recovered signal value that exceeds the smallest value among the continuous recovered signal values by a threshold is determined to be touched or approached by an external object.

17. The capacitive sensor of claim 15, wherein the controller further includes generating an average of the continuous recovered signal values, wherein a detecting plate corresponding to a recovered signal value that exceeds the average is determined to be touched or approached by an external object.

18. The capacitive sensor of claim 14, further comprising a memory for storing a lookup table, wherein the lookup table defines corresponding relationships between the continuous recovered signal values and the detecting plate being touched or approached, and the controller determines if at least one detecting plate is touched or approached by at least one external object by using the lookup table based on the continuous recovered signal values.

19. A capacitive sensor comprising:

a plurality of sequentially arranged detecting plates;

at least one reference plate disposed between the detecting plates;

a means for simultaneously providing an electrical signal to each detecting plate and providing the electrical signal or a DC potential to the reference plate, or simultaneously providing an electrical signal to each reference plate;

a means for generating a signal difference by subtraction between signals from each of the detecting plate and a preceding detecting plate and combining the signal differences to form a plurality of continuous signal differences;

a means for adding each signal difference of the continuous signal differences to all the preceding or following signal differences to generate a plurality of continuous recovered signal values; and

a means for determining if at least one detecting plate is touched or approached by at least one external object based on the continuous recovered signal values.

20. The capacitive sensor of claim 19, wherein the continuous recovered signal values further include an additionally added zero and each of the continuous recovered signal values correspond to one of the detecting plates, respectively.

21. The capacitive sensor of claim 20, wherein a detecting plate corresponding to a recovered signal value that exceeds the smallest value among the continuous recovered signal values by a threshold is determined to be touched or approached by an external object.

22. The capacitive sensor of claim 20, further comprising a means for generating an average of the continuous recovered signal values, wherein a detecting plate corresponding to a recovered signal value that exceeds the average is determined to be touched or approached by an external object.

23. The capacitive sensor of claim 19, further comprising a memory for storing a lookup table, wherein the lookup table defines corresponding relationships between the continuous recovered signal values and the detecting plate being touched or approached, and the controller determines if at least one detecting plate is touched or approached by at least one external object by using the lookup table based on the continuous recovered signal values.