Capacitive touch screen with square or rhombus conductive strips with extension pads

• US 8,830,205 B2
• Filed: 09/07/2012
• Issued: 09/09/2014
• Est. Priority Date: 10/09/2009
• Status: Active Grant

• Current Assignee: eGalax_eMPIA Technology Inc.
• Original Assignee: eGalax_eMPIA Technology Inc.
• Inventors: Chang, Chin-Fu, Lee, Cheng-Han
• Primary Examiner(s): Cerullo, Liliana
• Application Number:
  US13/606,482
• Publication Number:
  US 20120327027A1
• Time in Patent Office: 732 Days
• Field of Search: 345173-178, 178 1801- 1903, 298/46, 216/13, 438/100, 427/58, 427/216, 257 40- 41
• US Class Current: 345/174
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 2203/04102 Flexible digitiser, i.e. constructional details for allowing the whole digitising part of a device to be flexed or rolled like a sheet of paper
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• 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 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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

Abstract

The present invention provides a mutual capacitive multi-touch screen. The conductive strip pattern allows that, when a touch range of each external conductive object on the mutual capacitive multi-touch screen is larger than a predetermined condition, capacitive coupling between each external conductive object and first conductive strip is greater than capacitive coupling between each external conductive object and second conductive strip, such that the proportion of a driving signal flowing out of the first conductive strip via at least one first external conductive object in the external conductive objects and into the second conductive strip via at least one second external conductive object in the external conductive objects decreases as the number of second external conductive objects increases.

Claims

1. A detection method for a capacitive touch screen, comprising:

providing a capacitive touch screen in the shape of a rectangle with two opposing long sides and two opposing short sides, the capacitive touch screen including;

a plurality of first conductive strips being operatively provided with a driving signal during mutual capacitive coupling detection, wherein each first conductive strip is composed of a plurality of first connecting lines connected in series with a plurality of first conductive pads, and each first conductive strip is a square or a rhombus with an extension pad extending from each of the four sides, wherein the first conductive strips are in parallel with the short sides; and

a plurality of second conductive strips providing mutual capacitive coupling signals, wherein each second conductive strip is composed of a plurality of second connecting lines connected in series with a plurality of second conductive pads, and each second conductive strip is a square or a rhombus with an indented recess space on each of the four sides, wherein the second conductive strips are in parallel with the long sides, wherein each first conductive pad is a hexadecagon formed from a square or rhombus with outwardly-extending triangular extension pads and each second conductive pad is a hexadecagon formed from a square or rhombus with indented triangular recess spaces; and

providing at least one of the first conductive strips with the driving signal from one of the long sides, and receiving the mutual capacitive coupling signals from the second conductive strips at one of the short sides when the at least one first conductive strip is being provided with the driving signal.

2. A device including capacitive touch screen for detecting touches or approaches of external conductive objects, comprising:

the capacitive touch screen including;

a plurality of first conductive strips being operatively provided with a driving signal during mutual capacitive coupling detection, wherein each first conductive strip is composed of a plurality of first connecting lines connected in series with a plurality of first conductive pads, and each first conductive strip is a square or a rhombus with an extension pad extending from each of the four sides; and

a plurality of second conductive strips providing mutual capacitive coupling signals, wherein each second conductive strip is composed of a plurality of second connecting lines connected in series with a plurality of second conductive pads, and each second conductive strip is a square or a rhombus with an indented recess space on each of the four sides, wherein each first conductive pad is a hexadecagon formed from a square or rhombus with outwardly-extending triangular extension pads and each second conductive pad is a hexadecagon formed from a square or rhombus with indented triangular recess spaces; and

a controller providing the driving signal and receiving the mutual capacitive coupling signals from the second conductive strips when the at least one first conductive strip is being provided with the driving signal,

wherein the first conductive strips and the second conductive strips are exposed and separated from each other, and one of the extension pads is situated in each recess space.

3. The device including capacitive touch screen of claim 2, wherein the area of each first conductive pad after subtraction of the extension pads equals to the area of each second conductive pad after addition of the recess spaces, such that the exposed area of the first conductive pad is larger than that of the second conductive pad.

4. The device including a capacitive touch screen of claim 2, wherein the first conductive pads and the second conductive pads are on the same plane.

5. The device including a capacitive touch screen of claim 2, wherein the number of the first conductive strips is larger than that of the second conductive strips.

6. The device including a capacitive touch screen of claim 2, wherein each of the first connecting lines crosses over one of the second connecting lines or each of the second connecting lines crosses over one of the first connecting lines, wherein the intersecting first connecting lines and the second connecting lines are separated by an insulating material.

7. The device including a capacitive touch screen of claim 2, wherein the first conductive pads and the second conductive pads are not on the same plane, wherein the first conductive strips are closer to the external conductive objects than the second conductive strips.

8. The device including a capacitive touch screen of claim 7, wherein the capacitive touch screen further includes an insulating layer between the first conductive strips and the second conductive strips.

9. The device including a capacitive touch screen of claim 2, further comprising a display, wherein there is no insulating layer with a constant potential or with the driving signal between the display and the second conductive pads, wherein the constant potential or the driving signal is provided when the second conductive strips are providing the mutual capacitive coupling signals.

10. The device including a capacitive touch screen of claim 2, wherein the first conductive pads and the second conductive pads are not on the same plane, wherein the second conductive strips are closer to the display than the first conductive strips.

11. The device including a capacitive touch screen of claim 2, wherein the capacitive touch screen is in the shape of a rectangle with two opposing long sides and two opposing short sides, wherein the first conductive strips are arranged in parallel between the two short sides, and the second conductive strips are arranged in parallel between the two long sides.

12. The device including a capacitive touch screen of claim 2, wherein the capacitive touch screen further includes two first side conductive strips disposed on both sides of each first conductive strip and two second side conductive strips disposed on both sides of each second conductive strip, wherein each of the first side conductive strips is composed of the plurality of first connecting lines which are connected all in series with a plurality of half of the first conductive pads, and each of the second side conductive strips is composed of the plurality of second connecting lines which are connected all in series with a plurality of half of the second conductive pads.

13. The device including a capacitive touch screen of claim 2, wherein the second conductive strips are sequentially arranged in parallel and there are N second conductive strips, where N is a natural number, wherein the controller generates N−

1 differential values based on the mutual capacitive coupling signals, where each differential value is obtained by subtracting between the mutual capacitive coupling signals of a pair of adjacent second conductive strips.

14. The device including a capacitive touch screen of claim 2, wherein the second conductive strips are sequentially arranged in parallel and there are N second conductive strips, where N is a natural number, wherein the controller generates N−

2 dual differential values based on the mutual capacitive coupling signals, where each dual differential value is obtained by subtracting between the difference between the mutual capacitive coupling signals of the first two second conductive strips among three adjacent second conductive strips and the difference between the mutual capacitive coupling signals of the last two second conductive strips among the three adjacent second conductive strips.

15. The device including a capacitive touch screen of claim 2, wherein there are a plurality of isolated third conductive pads in exposed space between the first conductive strips and the second conductive strips, and the conductive pads are made of the same material as the first conductive strips.

16. The device including a capacitive touch screen of claim 2, further comprising a display, and there is no rear shielding layer for shielding from noise interference of the display between the first conductive strips and the display.

17. A capacitive touch screen for detecting touches or approaches of external conductive objects, comprising:

a plurality of first conductive strips being operatively provided with a driving signal during mutual capacitive coupling detection, wherein each first conductive strip is composed of a plurality of first connecting lines connected in series with a plurality of first conductive pads, and each first conductive strip is a square or a rhombus with an extension pad extending from each of the four sides; and

a plurality of second conductive strips providing mutual capacitive coupling signals, wherein each second conductive strip is composed of a plurality of second connecting lines connected in series with a plurality of second conductive pads, and each second conductive strip is a square or a rhombus with an indented recess space on each of the four sides,

wherein each first conductive pad is a hexadecagon formed from a square or rhombus with outwardly-extending triangular extension pads and each second conductive pad is a hexadecagon formed from a square or rhombus with indented triangular recess spaces,

wherein the first conductive strips and the second conductive strips are exposed and separated from each other, and one of the extension pads is situated in each recess space.

18. The capacitive touch screen of claim 17, wherein the area of each first conductive pad after subtraction of the extension pads equals to the area of each second conductive pad after addition of the recess spaces, such that the exposed area of the first conductive pad is larger than that of the second conductive pad.

19. The capacitive touch screen of claim 17, wherein the first conductive pads and the second conductive pads are on the same plane.

20. The capacitive touch screen of claim 17, wherein the number of the first conductive strips is larger than that of the second conductive strips.

21. The capacitive touch screen of claim 17, wherein each of the first connecting lines crosses over one of the second connecting lines or each of the second connecting lines crosses over one of the first connecting lines, wherein the intersecting first connecting lines and the second connecting lines are separated by an insulating material.

22. The capacitive touch screen of claim 17, wherein the first conductive pads and the second conductive pads are not on the same plane, wherein the first conductive strips are closer to the external conductive objects than the second conductive strips.

23. The capacitive touch screen of claim 17, further comprising two first side conductive strips disposed on both sides of each first conductive strip and two second side conductive strips disposed on both sides of each second conductive strip, wherein each of the first side conductive strips is composed of the plurality of first connecting lines which are connected all in series with a plurality of half of the first conductive pads, and each of the second side conductive strips is composed of the plurality of second connecting lines which are connected all in series with a plurality of half of the second conductive pads.