Device and method for detecting touch screen

• US 9,329,732 B2
• Filed: 10/12/2012
• Issued: 05/03/2016
• Est. Priority Date: 03/19/2008
• Status: Active Grant

• Current Assignee: eGalax_eMPIA Technology Inc.
• Original Assignee: eGalax_eMPIA Technology Inc.
• Inventors: Chang, Chin-Fu
• Primary Examiner(s): Lao, Lun-Yi
• Assistant Examiner(s): DEADERICK, ELLIOTT J
• Application Number:
  US13/650,438
• Publication Number:
  US 20140104222A1
• Time in Patent Office: 1,299 Days
• Field of Search: 345/103, 345/169, 345173-178, 178 1801- 1806, 178/19.01, 178/19.03
• US Class Current: 1/1
• 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 3/0443 using a single layer of sensing electrodes
• 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

Abstract

A driving signal is simultaneously provided to all first conductive strips arranged in parallel in a first direction in a touch screen, and mutual capacitive signals are detected from all second conductive strips arranged in parallel in a second direction. The mutual capacitive signals can be used for determining whether an external conductive object coupled to the ground is touching or approaching the touch screen or not even if water or other conductive object not coupled to ground is on the touch screen.

Claims

1. A device for detecting a touch screen comprising:

the touch screen including a plurality of first conductive strips and a plurality of second conductive strips; and

a controller for simultaneously providing a driving signal to all of the first conductive strips, wherein said controller includes a processor for controlling the driving signal;

wherein when the first conductive strips are provided with the driving signal, the controller detects signals of all of the second conductive strips to obtain a one-dimensional (1D) sensing information generated based on the signals of all of the second conductive strips, and determines if at least one external conductive object coupled to ground is touching or approaching the touch screen based on the 1D sensing information;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a first frequency during a predetermined period of time or a predetermined number of times of providing the driving signal;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a second frequency when, no approach or touch of an external conductive object coupled to ground is determined for the predetermined period of time or the predetermined number of times of providing the driving signal at the first frequency; and

wherein the first frequency is higher than the second frequency.

2. The device of claim 1, wherein the controller determines if at least one external conductive object coupled to ground is touching or approaching the touch screen based on if there is a value exceeding a threshold or if there is a zero-crossing.

3. The device of claim 1, wherein when it is determined that, based on the 1D sensing information, at least one external conductive object coupled to ground is touching or approaching the touch screen, the controller performs the following steps:

sequentially providing the driving signal to one of the first conductive strips;

detecting the signals of all of the second conductive strips when each of the first conductive strips is provided with the driving signal to obtain a 1D sensing information corresponding to a first conductive strip being provided with the driving signal generated based on the signals of all of the second conductive strips;

combining each 1D sensing information corresponding to the first conductive strip to generate a two-dimensional (2D) sensing information; and

determining the location of each external conductive object coupled to ground based on the 2D sensing information.

4. The device of claim 1, wherein when it is determined that, based on the 1D sensing information, an external conductive object coupled to ground is touching or approaching the touch screen, the controller performs the following steps:

sequentially providing the driving signal to a pair of the first conductive strips;

detecting the signals of all of the second conductive strips when each pair of the first conductive strips is simultaneously provided with the driving signal to obtain a 1D sensing information corresponding to the first conductive strips being provided with the driving signal generated based on the signals of all of the second conductive strips;

combining each 1D sensing information corresponding to the first conductive strips to generate a two-dimensional (2D) sensing information; and

determining the location of each external conductive object coupled to ground based on the 2D sensing information.

5. The device of claim 1, wherein when an approach or a touch of an external conductive object coupled to ground on the touch screen is determined while all of the first conductive strips are provided with the driving signal at the second frequency, the driving signal is provided to all of the first conductive strips at the first frequency again.

6. The device of claim 1, wherein the touch screen includes an insulating surface layer, a first sensing layer including the first conductive strips, an insulating layer, and a second sensing layer including the second conductive strips.

7. The device of claim 1, wherein the touch screen is a rectangle including two opposite long sides and two opposite short sides, wherein the first conductive strips are arranged in parallel with the two opposite short sides, and the second conductive strips are arranged in parallel with the two opposite long sides.

8. A method for detecting a touch screen comprising:

providing the touch screen including a plurality of first conductive strips, a plurality of second conductive strips, and a controller with a processor for controlling driving signal;

simultaneously providing the driving signal to all of the first conductive strips;

when the first conductive strips are provided with the driving signal, detecting signals of all of the second conductive strips to generate a one-dimensional (1D) sensing information based on the signals of all of the second conductive strips; and

determining whether at least one external conductive object coupled to ground is touching or approaching the touch screen based on the 1D sensing information;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a first frequency during a predetermined period of time or a predetermined number of times of providing the driving signal;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a second frequency when no approach or touch of an external conductive object coupled to ground on the touch screen is determined for the predetermined period of time or the predetermined number of times of providing the driving signal at the first frequency; and

wherein the first frequency is higher than the second frequency.

9. The method of claim 8, wherein at least one external conductive object coupled to ground is touching or approaching the touch screen is determined based on if there is a value exceeding a threshold or if there is a zero-crossing.

10. The method of claim 8, wherein when it is determined that, based on the 1D sensing information, at least one external conductive object coupled to ground is touching or approaching the touch screen, the method further comprising:

sequentially providing the driving signal to one of the first conductive strips;

detecting the signals of all of the second conductive strips when each of the first conductive strips is provided with the driving signal to obtain a 1D sensing information corresponding to the first conductive strip being provided with the driving signal generated from the signals of all of the second conductive strips;

combining each 1D sensing information corresponding to a first conductive strip to generate a two-dimensional (2D) sensing information; and

determining the location of each external conductive object coupled to ground based on the 2D sensing information.

11. The method of claim 8, wherein when it is determined that, based on the 1D sensing information, an external conductive object coupled to ground is touching or approaching the touch screen, the method further comprising:

sequentially providing the driving signal to a pair of the first conductive strips;

detecting the signals of all of the second conductive strips when each pair of the first conductive strips is simultaneously provided with the driving signal to obtain a 1D sensing information corresponding to the first conductive strips being provided with the driving signal generated from the signals of all of the second conductive strips;

combining each 1D sensing information corresponding to the first conductive strips to generate a two-dimensional (2D) sensing information; and

determining the location of each external conductive object coupled to ground based on the 2D sensing information.

12. The method of claim 8, wherein when an approach or a touch of an external conductive object coupled to ground on the touch screen is determined while all of the first conductive strips are provided with the driving signal at the second frequency, the driving signal is provided to all of the first conductive strips at the first frequency again.

13. The method of claim 8, wherein the touch screen includes an insulating surface layer, a first sensing layer including the first conductive strips, an insulating layer, and a second sensing layer including the second conductive strips.

14. The method of claim 8, wherein the touch screen is a rectangle including two opposite long sides and two opposite short sides, wherein the first conductive strips are arranged in parallel with the two opposite short sides, and the second conductive strips are arranged in parallel with the two opposite long sides.

15. A device for detecting a touch screen comprising:

the touch screen including a plurality of first conductive strips and a plurality of second conductive strips; and

a controller with a processor for simultaneously providing a driving signal to all of the first conductive strips, and when the first conductive strips are provided with the driving signal, detecting mutual capacitive signals of all of the second conductive strips to obtain a one-dimensional (1D) sensing information generated based on the signals of all of the second conductive strips, and determining whether at least one external conductive object coupled to ground is touching or approaching the touch screen based on the 1D sensing information to determine if a 2D mutual capacitive detection is to be performed, wherein the 2D mutual capacitive detection includes detecting mutual capacitive signals of all of the second conductive strips when a portion of the first conductive strips are being provided with the driving signal;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a first frequency during a predetermined period of time or a predetermined number of times of providing the driving signal;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a second frequency when no approach or touch of an external conductive object coupled to ground on the touch screen is determined for the predetermined period of time or the predetermined number of times of providing the driving signal at the first frequency; and

wherein the first frequency is higher than the second frequency.

16. A method for detecting a touch screen comprising:

providing the touch screen including a plurality of first conductive strips, a plurality of second conductive strips, and a controller with a processor for controlling a driving signal;

simultaneously providing the driving signal to all of the first conductive strips;

when the first conductive strips are provided with the driving signal, detecting mutual capacitive signals of all of the second conductive strips to obtain a one-dimensional (1D) sensing information generated based on the signals of all of the second conductive strips; and

determining whether at least one external conductive object coupled to ground is touching or approaching the touch screen based on the 1D sensing information to determine if a 2D mutual capacitive detection is to be performed, wherein the 2D mutual capacitive detection includes detecting mutual capacitive signals of all of the second conductive strips when a portion of the first conductive strips are being provided with the driving signal;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a first frequency during a predetermined period of time or a predetermined number of times of providing the driving signal;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a second frequency when no approach or touch of an external conductive object coupled to ground on the touch screen is determined for the predetermined period of time or the predetermined number of times of providing the driving signal at the first frequency; and

wherein the first frequency is higher than the second frequency.

17. A method for detecting a touch screen comprising:

providing the touch screen including a plurality of first conductive strips, a plurality of second conductive strips, and a controller with a processor for controlling a driving signal;

simultaneously providing the driving signal to all of the first conductive strips;

when the first conductive strips are provided with the driving signal, detecting signals of all of the second conductive strips to obtain a first one-dimensional (1D) sensing information;

determining whether at least one external conductive object coupled to ground is touching or approaching the touch screen based on the 1D sensing information;

when determining at least one external conductive object coupled to ground is touching or approaching the touch screen based on the 1D sensing information, the method further comprising;

determining at least a first 1D coordinate based on the first 1D sensing information;

determining a first mutual capacitive detection range based on each first 1D coordinate, and performing a mutual capacitive detection in the first mutual capacitive detection range to generate a second 1D sensing information corresponding to each first 1D coordinate;

generating at least a second 1D coordinate corresponding to each first 1D coordinate based on the second 1D sensing information corresponding to each first 1D coordinate; and

generating a 2D coordinate based on each first 1D coordinate and a corresponding second 1D coordinate;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a first frequency during a predetermined period of time or a predetermined number of times of providing the driving signal;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a second frequency when no approach or touch of an external conductive object coupled to ground on the touch screen is determined for the predetermined period of time or the predetermined number of times of providing the driving signal at the first frequency; and

wherein the first frequency is higher than the second frequency.

18. A method for detecting a touch screen comprising:

providing the touch screen including a plurality of first conductive strips, a plurality of second conductive strips, and a controller with a processor for controlling driving signal;

simultaneously providing the driving signal to all of the first conductive strips;

when the first conductive strips are provided with the driving signal, detecting signals of all of the second conductive strips to obtain a first one-dimensional (1D) sensing information;

determining whether at least one external conductive object coupled to ground is touching or approaching the touch screen based on the 1D sensing information;

when determining at least one external conductive object coupled to ground is touching or approaching the touch screen based on the 1D sensing information, the method further comprising;

determining at least a first 1D coordinate based on the first 1D sensing information;

determining a first mutual capacitive detection range based on each first 1D coordinate, and performing a mutual capacitive detection in the first mutual capacitive detection range to generate a second 1D sensing information corresponding to each first 1D coordinate;

generating at least a second 1D coordinate corresponding to each first 1D coordinate based on the second 1D sensing information corresponding to each first 1D coordinate;

determining a second mutual capacitive detection range based on each second 1D coordinate, and performing a mutual capacitive detection in the second mutual capacitive detection range to generate a third 1D sensing information corresponding to each second 1D coordinate;

generating at least a third 1D coordinate corresponding to each second 1D coordinate based on the third 1D sensing information corresponding to each second 1D coordinate; and

generating a 2D coordinate based on each second 1D coordinate and a corresponding third 1D coordinate;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a first frequency during a predetermined period of time or a predetermined number of times of providing the driving signal;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a second frequency when no approach or touch of an external conductive object coupled to ground on the touch screen is determined for the predetermined period of time or the predetermined number of times of providing the driving signal at the first frequency; and

wherein the first frequency is higher than the second frequency.

19. A method for detecting a touch screen, comprising:

providing the touch screen including a plurality of first conductive strips, a plurality of second conductive strips, and a controller with a processor for controlling a driving signal;

simultaneously providing the driving signal to all of the first conductive strips;

when the first conductive strips are provided with the driving signal, detecting signals of all of the second conductive strips to obtain a first one-dimensional (1D) sensing information;

determining whether at least one external conductive object coupled to ground is touching or approaching the touch screen based on the 1D sensing information; and

when determining at least one external conductive object coupled to ground is touching or approaching the touch screen based on the 1D sensing information, the method further comprising;

determining a first 1D coordinate of each external conductive object coupled to ground based on the first 1D sensing information;

detecting the signals of all of the second conductive strips to obtain a second 1D sensing information generated based on the signals of all the second conductive strips;

determining a second 1D coordinate of each external conductive object coupled to ground based on the second 1D sensing information;

forming a 2D coordinate based on each first 1D coordinate and a corresponding second 1D coordinate;

using an intersection of a first conductive strip and a second conductive strip closest to each 2D coordinate as a detected corresponding intersection; and

performing a mutual capacitive detection at each detected intersection corresponding to each 2D coordinate to detect a signal at each intersection corresponding to each 2D coordinate to determine a 2D coordinate of each external conductive object coupled to ground;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a first frequency during a predetermined period of time or a predetermined number of times of providing the driving signal;

wherein said processor controls the driving signal to be provided to all of the first conductive strips at a second frequency when no approach or touch of an external conductive object coupled to ground on the touch screen is determined for the predetermined period of time or the predetermined number of times of providing the driving signal at the first frequency; and

wherein the first frequency is higher than the second frequency.