EDGE-BY-EDGE INTEGRATION AND CONVERSION

• US 20140015768A1
• Filed: 09/27/2012
• Published: 01/16/2014
• Est. Priority Date: 07/12/2012
• Status: Active Grant

• Current Assignee: Parade Technologies, Ltd.
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Karpin, Oleksandr, Kremin, Victor, Musijchuk, Ihor, Kolych, Igor, Bihday, Volodymyr
• Granted Patent: US 9,405,401 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

An apparatus includes a transmission system configured to transmit a drive signal to a touch screen device. The apparatus also includes a reception system configured to integrate an output signal received from a touch screen device in response to the drive signals and to filter the integrated output signal to suppress noise in the output signal, wherein the reception system is configured to integrate the output signal for a period of time that is less than or equal to a signal period corresponding to the drive signal.

Claims

1. An apparatus comprising:

a transmission system configured to transmit a drive signal to a touch screen device; and

a reception system configured to integrate an output signal received directly from the touch screen device in response to the drive signal, wherein the reception system is configured to integrate the output signal over a first integration period to obtain a first integrated value and to integrate the output signal over a second integration period to obtain a second integrated value, wherein the first and second integration periods each correspond to less than or equal to a period of the drive signal, wherein the first integrated value and the second integrated value are independent from one another, and wherein the reception system comprises a buffer to concurrently and individually store the first integrated value and the second integrated value.

2. The apparatus of claim 1, wherein the first integration period of the output signal corresponds to the period of the drive signal.

3. The apparatus of claim 1, wherein the first integration period of the output signal corresponds to one-half of the period of the drive signal.

4. The apparatus of claim 1 wherein the buffer comprises:

a first buffer to store the first integrated value corresponding to the first integration period, wherein the first integration period corresponds to a positive period of the period of the drive signal; and

a second buffer to store the second integrated value corresponding to the second integration period, wherein the second integration period corresponds to a negative period of the period of the drive signal, wherein the reception system is configured to select a first filter from a plurality of filters for the first integrated value and to select a second filter from the plurality of filters for the second integrated value, and wherein the reception system is configured to filter integrated values stored in the first buffer, separately from integrated values stored in the second buffer.

5. The apparatus of claim 1, wherein the touch screen device is a self-capacitive sensing device.

6. The apparatus of claim 1, wherein the reception system is configured to detect a type of noise present in the touch screen device and select a type of filtering to perform on the integrated output signal in response to the detection of the type of noise present in the touch screen device.

23. The apparatus of claim 1, wherein a period of the drive signal comprises a rising edge and a subsequent period of the drive signal comprises a subsequent rising edge, and wherein the first integration period is between the rising edge and the subsequent rising edge.

24. The apparatus of claim 1, wherein a period of the drive signal comprises a rising edge and a falling edge, and wherein the second integration period is between the rising edge and the falling edge.

7. A method comprising:

integrating, by a touch detection system, a signal received from a touch screen device, wherein the signal corresponds to a drive signal applied to the touch screen device, and wherein the integrating comprises;

integrating the signal over a first integration period to obtain a first integrated value; and

integrating the signal over a second integration period to obtain a second integrated value, wherein the first and second integration periods each correspond to less than or equal to a period of the drive signal, wherein the first integrated value and the second integrated value are independent from one another,

concurrently and individually storing, in a buffer, the first and second integrated value in a buffer of the touch detection system;

filtering, by the touch detection system, the integrated signal with a group of previously integrated signals with a noise suppression filter selected from a plurality of noise suppression filters based on a type of noise present in the touch screen device; and

detecting, by the touch detection system, from the filtered signal whether an object is proximate to a panel in the touch screen device.

8. The method of claim 7, further comprising detecting, by the touch detection system, the type of noise present in the touch screen device prior to receiving the signal from the touch screen device.

9. The method of claim 8, wherein detecting the type of noise present in the touch screen device further comprises identifying a frequency of the noise present in the touch screen device, and wherein filtering the integrated signal further comprises averaging the integrated signal with the group of previously integrated signals or selecting a median filter for the group of previously integrated signals based, at least in part, on the frequency of the noise present in the touch screen device.

10. The method of claim 8, wherein detecting the type of noise present in the touch screen device further comprises determining characteristics of the noise present in the touch screen device correspond to random noise or high frequency noise, and wherein filtering the integrated signal further comprises averaging the integrated signal with the group of previously integrated signals or selecting a median filter for the group of previously integrated signals based, at least in part, on the characteristics of the noise present in the touch screen device.

11. The method of claim 7 further comprising transmitting, by the touch detection system, the drive signal to the touch screen device, wherein the touch screen device is configured to output the signal to the touch detection system in response to the drive signal.

12. The method of claim 11, wherein integrating the signal is performed by accumulating the output signal over the first integration period of the signal that corresponds to the period of the drive signal.

13. The method of claim 11, wherein integrating the signal is performed by accumulating the output signal over the first integration period that corresponds to a one-half of the period of the drive signal.

14. The method of claim 11 further comprising:

buffering, by the touch detection system, integrated signals corresponding to a positive period of the drive signal and a negative period of the drive signal in different buffers; and

separately filtering, by the touch detection system, the integrated signals stored in the different buffers.

15. A method comprising:

detecting, by a touch screen system, characteristics of noise present in a touch screen panel;

selecting, by the touch screen system, a noise suppression filter from a plurality of noise suppression filters based, at least in part, on the characteristics of the noise present in the touch screen panel; and

suppressing, by the touch screen system, noise from an output signal from the touch screen panel with the selected noise suppression filter.

16. The method of claim 15 further comprising detecting, by the touch screen system, from the noise suppressed signal whether an object is proximate to the touch screen panel.

17. The method of claim 15 further comprising:

transmitting, by the touch screen system, drive signals to the touch screen panel; and

receiving, by the touch screen system, the output signal from the touch screen panel in response to the drive signals.

18. The method of claim 17 further comprising performing edge-by-edge integration of the output signal over a duration that is less than or equal to a signal period of the drive signals.

19. The method of claim 18 further comprising:

buffering, by the touch screen system, integrated signals corresponding to a positive period of the drive signal and a negative period of the drive signal in different buffers; and

separately filtering, by the touch screen system, the integrated signals stored in the different buffers.

20. The method of claim 15, wherein the noise suppression filter includes at least one of an average filter, a median filter to filter, an amplitude limiting filter, or a sorted order filter.

21-22. -22. (canceled)