Active stylus and capacitive position detection system

• US 10,521,027 B2
• Filed: 02/14/2018
• Issued: 12/31/2019
• Est. Priority Date: 07/27/2011
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: Kremin, Viktor, Ryshtun, Andriy, Wright, David G.
• Primary Examiner(s): Ritchie, Darlene M
• Application Number:
  US15/896,950
• Publication Number:
  US 20180173331A1
• Time in Patent Office: 685 Days
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 2203/04114 Touch screens adapted for alternating or simultaneous interaction with active pens and passive pointing devices like fingers or passive pens
• CPC Class Codes: G06F 3/033 Pointing devices displaced or positioned by the user , e.g. mice, trackballs, pens or joysticks; Accessories therefor digitisers characterised by the transducing means G06F3/041
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/0383 Signal control means within the pointing device
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0414 using force sensing means to determine a position
• CPC Class Codes: G06F 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0442 using active external devices, e.g. active pens, for transmitting changes in electrical potential to be received by the digitiser
• 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

Abstract

An elongated stylus is configured to be capacitively coupled with a sensor array providing a plurality of electrodes to indicate a position on the sensor array. The stylus includes a housing having an end in an elongated direction of the housing, a conductive tip disposed at least partially extended from the end of the housing, an electrode disposed around the conductive tip and configured to at least partially expose the conductive tip, and a signal transmit drive circuit configured to provide a signal. Control is performed to form an electrical connection between the electrode and a ground and an electrical connection between the electrode and the signal transmit drive circuit when the elongated stylus is activated for capacitive coupling with the sensor array.

Claims

1. An elongated stylus configured to be capacitively coupled with a sensor array that provides a plurality of electrodes and is controlled by a sensor controller, to indicate a position on the sensor array, the stylus comprising:

a housing having an end in an elongated direction of the housing;

a first electrode disposed to at least partially extend from the end of the housing;

a second electrode disposed around the first electrode;

a signal transmit drive circuit configured to transmit a stylus signal to the sensor array; and

a stylus controller configured to control transmission of the stylus signal to the sensor array via at least one of the first electrode and the second electrode;

wherein the stylus controller is configured to synchronize the transmission of the stylus signal to the sensor array via the first electrode with a sensor signal transmitted from the sensor controller and configured to electrically control the second electrode disposed around the first electrode,

wherein the stylus signal is modulated and differentiated from the sensor signal that is code modulated, and

wherein the stylus controller is configured to controllably ground the second electrode, while the modulated stylus signal is supplied to the first electrode.

2. The elongated stylus of claim 1, wherein the stylus controller is configured to synchronize the transmission of the stylus signal with a synchronization signal transmitted from the sensor controller.

3. The elongated stylus of claim 1, wherein the stylus controller is configured to synchronize the transmission of the stylus signal with a timing data signal transmitted from the sensor controller.

4. The elongated stylus of claim 1, wherein the stylus controller is configured to synchronize the transmission of the stylus signal with the sensor signal that is transmitted from the sensor controller wirelessly.

5. The elongated stylus of claim 1, wherein the stylus controller is configured to synchronize the transmission of the stylus signal with the sensor signal capacitively transmitted via the sensor array from the sensor controller.

6. The elongated stylus of claim 1, wherein the stylus signal is phase modulated, frequency modulated, amplitude modulated, or code modulated.

7. The elongated stylus of claim 1, wherein the stylus controller is configured to control the second electrode disposed around the first electrode to transmit the stylus signal to the sensor array.

8. The elongated stylus of claim 7, wherein the stylus controller is further configured to synchronize the transmission of the stylus signal to the sensor array with the sensor signal, using a synchronization signal received via an antenna inside the stylus.

9. The elongated stylus of claim 7, wherein the stylus controller is configured to control the second electrode disposed around the first electrode to selectively transmit the stylus signal via the second electrode and the first electrode.

10. The elongated stylus of claim 9, wherein the stylus controller is configured to control the second electrode disposed around the first electrode to selectively transmit the stylus signal via the second electrode and the first electrode in synchronization with the sensor signal transmitted from the sensor controller.

11. A capacitive position detection system comprising:

(i) an active stylus configured to be capacitively coupled with a sensor array to indicate a position on the sensor array, the active stylus comprising;

a housing having an end in an elongated direction of the housing;

a first electrode disposed to at least partially extend from the end of the housing;

a second electrode disposed around the first electrode;

a signal transmit drive circuit configured to transmit a stylus signal to the sensor array; and

a stylus controller configured to control transmission of the stylus signal to the sensor array via at least the first electrode and configured to electrically control the second electrode disposed around the first electrode;

(ii) the sensor array including a first set of conductors disposed in a first direction and a second set of conductors disposed in a second direction different from the first direction, controlled by a sensor controller, wherein a finger and the active stylus are detectable on the sensor array based on transmission signals supplied to the first set of conductors and reception signals received in the second set of conductors and based on stylus signals transmitted from the active stylus and received in the first and second sets of conductors,

wherein the sensor controller is configured to transmit a sensor signal to the active stylus to enable the stylus controller to synchronize the transmission of the stylus signal via the first electrode of the active stylus to the sensor array,

wherein the stylus signal is modulated and differentiated from the sensor signal that is code modulated, and

wherein the stylus controller is configured to controllable ground the second electrode, while the modulated stylus signal is supplied to the first electrode.

12. The capacitive position detection system of claim 11, wherein the stylus controller is configured to control the second electrode disposed around the first electrode to transmit the stylus signal to the sensor array.

13. The capacitive position detection system of claim 11, wherein the stylus controller is further configured to synchronize the transmission of the stylus signal to the sensor array with the sensor signal, using a synchronization signal received via an antenna inside the stylus.

14. The capacitive position detection system of claim 11, wherein the sensor signal is wirelessly transmitted to the active stylus.

15. The capacitive position detection system of claim 11, wherein the sensor controller is configured to transmit the sensor signal that is code modulated based on a code signal by supplying the transmission signals to the first set of conductors.

16. The capacitive position detection system of claim 11, wherein the sensor controller is configured to transmit the sensor signal by supplying the transmission signals to the first set of conductors.

17. The capacitive position detection system of claim 11, wherein the stylus signal is phase modulated, frequency modulated, amplitude modulated, code modulated.

18. The capacitive position detection system of claim 11, wherein the stylus controller is configured to control the second electrode disposed around the first electrode to selectively transmit the stylus signal via the second electrode and the first electrode.

19. The capacitive position detection system of claim 18, wherein the stylus controller is configured to control the second electrode disposed around the first electrode to selectively transmit the stylus signal via the second electrode and the first electrode in synchronization with the sensor signal transmitted from the sensor controller.