Touch sensing apparatus using varying signal delay input to a flip-flop

• US 7,696,986 B2
• Filed: 12/28/2006
• Issued: 04/13/2010
• Est. Priority Date: 01/21/2006
• Status: Expired due to Fees

• Current Assignee: Gold Charm Limited (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Hong Fu Jin Precision Industry (Shenzhen) Co., Ltd. (Hon Hai Precision Industry Co., Ltd.), Hon Hai Precision Industry Co., Ltd.
• Inventors: Chung, Shin-Hong, Hsieh, Kuan-Hong, Wang, Han-Che, Lin, Shi-Quan, Zhao, Xin
• Primary Examiner(s): Mengistu, Amare
• Assistant Examiner(s): Lee, Gene W
• Application Number:
  US11/616,893
• Publication Number:
  US 20070171209A1
• Time in Patent Office: 1,202 Days
• Field of Search: 178 1801- 1807, 178 2001- 2004, 178 1901- 1907, 345/173, 324/663, 324/415, 200/600
• US Class Current: 345/173
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

A touch sensing apparatus is provided. The apparatus includes a flip-flop (15), a sensor (13), an AC signal (14), and a detector (16). The AC signal supplies AC signals to the flip-flop. The flip-flop outputs a first output signal at the output of flip-flop when the sensor is not touched. The sensor receives electricity signals from the object, and causes a delay of the AC signal inputted to the first input of the flip-flop, the delay of the AC signal to be inputted to the first input of the flip-flop further causes the flip-flop to output a second output signal at the output of the flip-flop. The detector detects a change from the first output signal to the second output signal at the output of the flip-flop and accordingly identifies a touch on the sensor.

Claims

1. A touch sensing apparatus comprising:

a flip-flop having a first input, a second input, and an output;

an alternating current (AC) signal source for supplying AC signals to the first input and the second input of the flip-flop;

a sensor connected to the first inputs of the flip-flop and configured for receiving electricity signals from an object that touches the sensor;

a first integration circuit interposed between the second input of the flip-flop and the AC signal source and for delaying the AC signal inputted to the second input of the flip-flop;

a second integration circuit connecting the first input of the flip-flop to the AC signal source and for delaying the AC signal inputted to the first input of the flip-flop; and

a detector electrically connected to the output of the flip-flop and for detecting a change at the output of the flip-flop;

wherein the flip-flop outputs a first output signal at the output thereof when the sensor is not touched;

the sensor receives electricity signals from the object, and causes a delay of the AC signal inputted to the first input of the flip-flop, the delay of the AC signal inputted to the first input of the flip-flop further causing the flip-flop to output a second output signal at the output thereof; and

the detector detects a change from the first output signal to the second output signal at the output of the flip-flop and accordingly identifies a touch on the sensor.

2. The touch sensing apparatus as described in claim 1, further comprising a microcontroller unit (MCU) for executing a predetermined task after the detector identifies the touch on the sensor.

3. The touch sensing apparatus as described in claim 1, wherein the flip-flop is a D-type flip-flop.

4. The touch sensing apparatus as described in claim 1, further comprising a differential signal source configured for generating a positive signal and a negative signal.

5. The touch sensing apparatus as described in claim 4, further comprising two conductors each having a first terminal and a second terminal, the first terminal being connected to the positive signal or the negative signal of the differential signal source correspondingly.

6. The touch sensing apparatus as described in claim 5, further comprising two capacitors each respectively connected to the second terminal of the conductors.

7. The touch sensing apparatus as described in claim 6, wherein the sensor locates between the two conductors and forms two simulated capacitors with the two conductors for offsetting environmental noise.

8. The touch sensing apparatus as described in claim 4, wherein the differential signal source is further provided for providing an alternating magnetic field for the touch sensing apparatus.