Method of calibrating sensitivity of a touch input device and touch input device employing the same

• US 9,377,898 B2
• Filed: 08/06/2014
• Issued: 06/28/2016
• Est. Priority Date: 08/19/2013
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Shin, Ji-Hye
• Primary Examiner(s): PATEL, PREMAL R
• Application Number:
  US14/453,483
• Publication Number:
  US 20150049064A1
• Time in Patent Office: 692 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/044 by capacitive means
• 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 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A method of calibrating sensitivity of a pressure based touch input device is disclosed. In one aspect, the method includes generating continuous input signals each having a value that is based on the magnitude pressure applied to the touch input device and sampling the continuous input signals at a predetermined rate to generate sampling signals. The method also includes determining whether to perform a sensitivity calibration of the touch input device based on a first threshold range and the sampling signals and selecting a sensitivity calibration parameter to be applied to the sensitivity calibration from among a plurality of pre-stored parameters. The selecting is based on the absolute values of the sampling signals. The method further includes performing the sensitivity calibration based on the sensitivity calibration parameter.

Claims

1. A method of calibrating sensitivity of a pressure based touch input device, the method comprising:

generating a plurality of continuous input signals each having a value that is based at least in part on the magnitude of pressure applied to the touch input device;

sampling the continuous input signals at a predetermined frame rate so as to generate a plurality of sampling signals;

determining whether to perform a sensitivity calibration of the touch input device based at least in part on a first threshold range and the sampling signals;

selecting a sensitivity calibration parameter to be applied to the sensitivity calibration from a plurality of pre-stored parameters, wherein the selecting is performed based at least in part on the absolute values of the sampling signals; and

performing the sensitivity calibration based at least in part on the selected sensitivity calibration parameter.

2. The method of claim 1, wherein the determining includes:

calculating the difference between a value of an (N)th sampling signal and a value of an (N−

1)th sampling signal;

generating status data for the touch input device based at least in part on the calculated difference and the first threshold range; and

determining whether to perform the sensitivity calibration based at least in part on the status data.

3. The method of claim 2, wherein the generating of the status data includes:

determining whether the difference is negative; and

determining whether the difference is in the first threshold range.

4. The method of claim 1, wherein the determining includes:

sequentially comparing the absolute value of an (N)th sampling signal with a plurality of reference values until the absolute value of the (N)th sampling signal is greater than or substantially equal to an (M)th reference value; and

selecting a parameter corresponding to the (M)th reference value as the sensitivity calibration parameter.

5. The method of claim 4, wherein the performing includes:

setting the value of the (N)th sampling signal as a reference level; and

changing the first threshold range to a second threshold range based at least in part on the sensitivity calibration parameter.

6. The method of claim 5, wherein the second threshold range increases as variation in the continuous input increases.

7. The method of claim 1, wherein the determining includes:

selecting sampling signals which have a value greater than a third threshold value;

calculating the difference between a value of an (N)th sampling signal and a value of an (N−

1)th sampling signal;

generating status data for the touch input device based at least in part on the first threshold range and the calculated difference; and

determining whether to perform the sensitivity calibration based at least in part on the status data.

8. The method of claim 7, wherein the generating of the status data includes:

determining whether the difference is negative; and

determining whether the difference is in the first threshold range.

9. The method of claim 8, wherein the performing includes:

setting the value of the (N)th sampling signal as a reference level;

changing the third threshold value to a fourth threshold value based at least in part on the sensitivity calibration parameter; and

changing the first threshold range to a second threshold range based at least in part on the sensitivity calibration parameter.

10. The method of claim 9, wherein the second threshold range increases as variation in the continuous input signals increases and wherein the fourth threshold value is the sum of the value of the (N)th frame signal and the third threshold value.

11. A pressure based touch input device, comprising:

a pressure sensor configured to sense pressure applied to the touch input device, wherein the pressure sensor comprises i) a first electrode layer, ii) an elastic member formed over the first electrode layer, and iii) a second electrode layer formed over the elastic member, wherein the second electrode layer opposes the first electrode layer; and

a controller configured to generate a plurality of sampling signals at a predetermined frame rate based at least in part on the magnitude of the sensed pressure and perform a sensitivity calibration of the touch input device based at least in part on the sampling signals.

12. The device of claim 11, wherein the pressure sensor is configured to detect a touch input signal based at least in part on a change in capacitance of the pressure sensor created due to the applied pressure.

13. The device of claim 11, wherein the controller is further configured to:

generate a plurality of continuous input signals each having a value that is based at least in part on the magnitude of the pressure;

sample the continuous input signals at the predetermined frame rate to generate the plurality of sampling signals;

determine whether to perform a sensitivity calibration of the touch input device based at least in part on a first threshold range and the sampling signals;

select a sensitivity calibration parameter to be applied to the sensitivity calibration from a plurality of pre-stored parameters based at least in part on the absolute values of the sampling signals; and

perform the sensitivity calibration based at least in part on the sensitivity calibration parameter.

14. The device of claim 13, wherein the controller is further configured to:

calculate the difference between a value of an (N)th sampling signal and a value of an (N−

1)th sampling signal;

generate status data for the touch input device based at least in part on the calculated difference and the first threshold range; and

determine whether to perform the sensitivity calibration based at least in part on the status data.

15. The device of claim 13, wherein the controller is further configured to:

sequentially compare the absolute value of an (N)th sampling signal with a plurality of reference values until the absolute value of the (N)th sampling signal is greater than or substantially equal to an (M)th reference value;

select a parameter corresponding to the (M)th reference value as the sensitivity calibration parameter;

set the value of the (N)th frame signal as a reference level; and

change the first threshold range to a second threshold range based at least in part on the sensitivity calibration parameter.

16. The device of claim 13, wherein the controller is further configured to:

select sampling signals which have a value greater than a third threshold value;

calculate the difference between a value of an (N)th sampling signal and a value of an (N−

1)th sampling signal;

generate status data for the touch input device based at least in part on the first threshold range and the calculated difference; and

determine whether to perform the sensitivity calibration based at least in part on the status data.

17. The device of claim 16, wherein the controller is further configured to:

sequentially compare the absolute value the (N)th frame signal with a plurality of reference values until the absolute value of the (N)th sampling signal is greater than or substantially equal to an (M)th reference value;

select a parameter corresponding to the (M)th reference value as the sensitivity calibration parameter;

set the value of the (N)th frame signal as a reference level;

change the third threshold value to a fourth threshold value based at least in part on the sensitivity calibration parameter; and

change the first threshold range to a second threshold range based at least in part on the sensitivity calibration parameter.

18. A method of calibrating sensitivity of a pressure based touch input device, comprising:

generating a plurality of sampling signals at a predetermined frame rate based at least in part on the magnitude of pressure applied to the touch input device;

determining whether to perform a sensitivity calibration of the touch input device based at least in part on the sampling signals;

selecting a sensitivity calibration parameter to be applied to the sensitivity calibration from a plurality of pre-stored parameters, wherein the selecting is prepared based at least in part on the absolute values of the sampling signals; and

performing the sensitivity calibration based at least in part on the sensitivity calibration parameter.

19. The method of claim 18, wherein the generating comprises:

generating a plurality of continuous input signals each having a value that is based at least in part on the magnitude of the pressure applied to the touch input device; and

sampling the continuous input signals at a predetermined frame rate.

20. The method of claim 18, wherein the determining comprises:

calculating the difference between a value of an (N)th sampling signal and a value of an (N−

1)th sampling signal;

generating status data for the touch input device based at least in part on the difference and a first threshold range; and

determining whether to perform the sensitivity calibration based at least in part on the status data.