STYLUS WITHOUT ACTIVE COMPONENTS AND AN ASSOCIATED TOUCH PANEL

• US 20150199035A1
• Filed: 03/05/2014
• Published: 07/16/2015
• Est. Priority Date: 01/13/2014
• Status: Abandoned Application

• Current Assignee: Himax Technologies Ltd. (Himax Technologies Incorporated)
• Original Assignee: Himax Technologies Ltd. (Himax Technologies Incorporated)
• Inventors: CHANG, YAW-GUANG, Huang, Guan-Ying
• Application Number:
  US14/198,558
• Publication Number:
  US 20150199035A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

A stylus without active components includes a housing, and a resonant circuit, such as an LC resonant circuit, disposed in the housing. The resonant circuit is operatively configured to one of a plurality of resonant frequencies respectively associated with a plurality of function modes.

Claims

1. A stylus without active components, the stylus comprising:

a housing; and

a resonant circuit disposed in the housing, the resonant circuit being operatively configured to one of a plurality of resonant frequencies respectively associated with a plurality of function modes.

2. The stylus of claim 1, wherein the plurality of function modes comprise a pen-tip pressure detection mode, an erase mode and a right-key mode.

3. The stylus of claim 1, wherein the resonant circuit configured with the associated function mode absorbs a transmit (Tx) signal from a touch panel, and then emits a receive (Rx) signal to the touch panel, thereby the touch panel detecting the associated function mode of the stylus according to the Rx signal.

4. The stylus of claim 1, wherein the resonant circuit comprises an LC resonant circuit.

5. The stylus of claim 4, wherein the LC resonant circuit comprises:

a basis inductor;

a first capacitor; and

a variable second capacitor with a value varying according to pressure of a pen tip, and the value of the variable second capacitor being substantially smaller than a value of the first capacitor;

wherein the basis inductor, the first capacitor and the second capacitor are connected in parallel to result in a first resonant frequency which is decided based on a value of the basis inductor and a sum of values of the first capacitor and the variable second capacitor.

6. The stylus of claim 5, wherein the LC resonant circuit generates and emits a signal with a phase being detected to determine the pressure of the pen tip.

7. The stylus of claim 5, further comprising:

a third capacitor; and

a first switch connected with the third capacitor in series;

wherein the series-connected third capacitor and the first switch are connected in parallel to the basis inductor, the first capacitor and the variable second capacitor, thereby resulting in a second resonant frequency which is decided based on the value of the basis inductor and a sum of values of the first capacitor, the variable second capacitor and the third capacitor, when the first switch is closed.

8. The stylus of claim 7, further comprising:

a fourth capacitor; and

a second switch connected with the fourth capacitor in series;

wherein the series-connected fourth capacitor and the second switch are connected in parallel to the basis inductor, the first capacitor and the variable second capacitor, thereby resulting in a third resonant frequency which is decided based on the value of the basis inductor and a sum of values of the first capacitor, the variable second capacitor and the fourth capacitor, when the second switch is closed.

9. A touch panel operable with a stylus having no active components, the touch panel comprising:

a plurality of conductive channels;

a transmit (Tx) and receive (Rx) unit configured to send Tx signals to and then receive Rx signals from the conductive channels in order;

an analog front-end (AFE) configured to convert the received RX signal to a digital signal; and

a modulator configured to retrieve amplitude and phase of the digital signal;

wherein the Tx signals are sent in a frequency-hopping manner for all the conductive channels through a plurality of resonant frequencies respectively associated with a plurality of function modes of the stylus.

10. The touch panel of claim 9, further comprising:

a central processing unit (CPU) configured to process the amplitude of the digital signal to determine a touch position of the stylus, and to process the phase of the digital signal to determine pen-tip pressure of the stylus.

11. The touch panel of claim 9, wherein the plurality of function modes comprise a pen-tip pressure detection mode, an erase mode and a right-key mode.