Electrical touch pad regulating sensitivity based on ambient humidity and method thereof

• US 7,948,478 B2
• Filed: 09/12/2007
• Issued: 05/24/2011
• Est. Priority Date: 04/10/2007
• Status: Expired due to Fees

• Current Assignee: Hon Hai Precision Industry Co., Ltd.
• Original Assignee: Hon Hai Precision Industry Co., Ltd.
• Inventors: Chuang, Tsung-Jen
• Primary Examiner(s): Mengistu; Amare
• Assistant Examiner(s): Lee; Gene W
• Application Number:
  US11/853,833
• Publication Number:
  US 20080252613A1
• Time in Patent Office: 1,350 Days
• Field of Search: 345173-178, 178 1801- 1811
• US Class Current: 345/173
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0418 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 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

An electrical touch pad includes a touch sensor for detecting operational inputs, and generating analog signals according to the operational inputs; a touch detection unit for receiving analog signals, amplifying the analog signals by a controllable gain to generate amplified analog signals, converting the amplified analog signals to generate digital signals, and sending the digital signals to a processor to determine a touched location; a humidity detection unit for detecting ambient humidity and determining a humidity level; and a humidity compensation unit for receiving the humidity level, generating a gain regulation signal to control the touch detection unit to regulate the controllable gain according to the humidity level. Thereby, in erratic behavior of the electrical touch pad can be prevented and stability of the touch pad is enhanced. A related method for regulating sensitivity of the electrical touch pad is also provided.

Claims

1. An electrical touch pad comprising:

a touch sensor for detecting operational inputs, and generating analog signals according to the operational inputs;

a touch detection unit for receiving the analog signals, amplifying the analog signals by a controllable gain to generate amplified analog signals, converting the amplified analog signals to generate digital signals, and sending the digital signals to a processor to determine a touched location;

a humidity detection unit for detecting ambient humidity and determining a humidity level; and

a humidity compensation unit for receiving the humidity level, generating a gain regulation signal to control the touch detection unit to regulate the controllable gain according to the humidity level.

2. The electrical touch pad according to claim 1, wherein the humidity compensation unit comprises a humidity analysis module and a gain adjustment module;

the humidity analysis module compares the humidity level with a high threshold;

if the humidity level is higher than the high threshold, the gain adjustment module generates the gain regulation signal to signal the touch detection unit to decrease the controllable gain.

3. The electrical touch pad according to claim 2, wherein the humidity analysis module compares the humidity level with a low threshold;

if the humidity level is lower than the low threshold, the gain adjustment module generates the gain regulation signal to control the touch detection unit to increase the controllable gain.

4. The electrical touch pad according to claim 3, wherein the gain adjustment module does not generate any gain regulation signals when the humidity level is between the low threshold and the high threshold.

5. The electrical touch pad according to claim 1, wherein the humidity compensation unit comprises a humidity analysis module and a gain adjustment module;

the humidity analysis module obtains a predetermined gain value corresponding to the humidity level received from the humidity detection unit;

the gain adjustment module generates the gain regulation signal according to the predetermined gain value.

6. The electrical touch pad according to claim 5, wherein the humidity compensation unit further comprises a memory for storing a plurality of predetermined gain values corresponding to humidity levels;

the humidity analysis module searches the memory to obtain one of the predetermined gain values corresponding to the humidity level.

7. The electrical touch pad according to claim 5, wherein the humidity compensation unit further comprises a memory for storing an arithmetic function program indicating that a predetermined gain value is a function of a humidity level;

the humidity analysis module performs the arithmetic function program to obtain the predetermined gain value corresponding to the humidity level.

8. A method for regulating sensitivity of an electrical touch pad, comprising:

receiving analog signals generated by the electrical touch pad;

amplifying the analog signals by a controllable gain to generate amplified analog signals;

detecting ambient humidity;

determining a humidity level;

generating a gain regulation signal for regulating the controllable gain according to the humidity level;

regulating the controllable gain according to the gain regulation signal;

converting the amplified analog signals to generate digital signals; and

determining a touched location according to the digital signals.

9. The method for regulating sensitivity of electrical touch pad according to claim 8, wherein the method of generating a gain regulation signal comprises:

comparing the humidity level with a high threshold; and

generating the gain regulation for decreasing the controllable gain if the humidity level is higher than the high threshold.

10. The method for regulating sensitivity of electrical touch pad according to claim 9, wherein the method of generating the gain regulation signal further comprises:

comparing the humidity level with a low threshold; and

generating the gain regulation for increasing the controllable gain if the humidity level is lower than the low threshold.

11. The method for regulating sensitivity of electrical touch pad according to claim 8, wherein the method of generating the gain regulation signal comprises:

obtaining a predetermined gain value corresponding to the humidity level; and

generating the gain regulation signal according to the predetermined gain value.

12. The method for regulating sensitivity of electrical touch pad according to claim 11, wherein the method of obtaining the predetermined gain value comprises:

providing a memory for storing a plurality of predetermined gain values corresponding to humidity levels;

searching the memory to obtain one of the predetermined gain values corresponding to the humidity level.

13. The method for regulating sensitivity of electrical touch pad according to claim 11, wherein the method of obtaining the predetermined gain value comprises:

providing a memory for storing an arithmetic function program, the arithmetic function program indicates that a predetermined gain value is a function of a humidity level; and

performing the arithmetic function program to obtain one of the predetermined gain values corresponding to the humidity level.