COMBINATION TOUCH AND TRANSDUCER INPUT SYSTEM AND METHOD

• US 20100085325A1
• Filed: 09/28/2009
• Published: 04/08/2010
• Est. Priority Date: 10/02/2008
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: Hadizad, Peyman, Smit, Bernardus H., King-Smith, Oliver P.
• Granted Patent: US 8,482,545 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• 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 2203/04108 Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction
• 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 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/04162 for exchanging data with external devices, e.g. smart pens, via the digitiser sensing hardware
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• 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 3/0441 using active external devices, e.g. active pens, for receiving changes in electrical potential transmitted by the digitiser, e.g. tablet driving signals
• 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
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

A combination touch and transducer input system is provided, which facilitates user input into an electronic system with a finger and/or a transducer (e.g., a stylus). The system includes a transducer configured to generate an electric field, and a sensor including an array of electrodes and a controller. The transducer is configured to transmit digital data, such as pen pressure data and switch status data, to the sensor. For example, the transducer comprises electronic circuitry configured to encode the digital data in a signal for transmission to the sensor. The sensor controller is configured to operate both in a touch sensing mode and in a transducer sensing mode. During the touch sensing mode, the controller determines a position of a proximate object (e.g., a finger) by capacitively sensing the object with the array of electrodes. During the transducer sensing mode, the controller determines a position of the transducer based on a signal received by the array of electrodes from the transducer, and also receives and decodes the digital data encoded in the received signal. Digital data can be encoded in a signal using any suitable digital modulation techniques, such as a Frequency-Shift Keying (FSK) technique.

Claims

1. A combination touch and transducer input system, comprising:

a transducer configured to generate an electric field;

an array of electrodes; and

a controller coupled to the array of electrodes, the controller being configured to;

when operating in a touch mode, determine a position of a proximate object by capacitively sensing the object with the array of electrodes; and

when operating in a transducer mode, determine a position of the transducer by measuring attributes of a plurality of sensing signals, the plurality of sensing signals being induced in the array of electrodes by the electric field generated by the transducer;

wherein the transducer is configured to transmit digital data to the array of electrodes, and the controller is configured to receive the digital data via the array of electrodes.

2. The system of claim 1, wherein the controller is configured, when operating in the transducer mode, to measure amplitudes of the plurality of sensing signals.

3. The system of claim 1, wherein the transducer comprises electronic circuitry configured to selectively generate the electric field at multiple frequencies and to encode the digital data in frequency shifts of the generated field, and the controller is configured to detect the plurality of sensing signals at multiple frequencies and to decode the digital data encoded in the frequency shifts.

4. The system of claim 1, wherein the digital data includes one or more of a pressure data, switch status data, and transducer identification data.

5. The system of claim 1, wherein the transducer comprises electronic circuitry configured to encode the digital data in phase shifts or amplitude shifts of the generated electric field.

6. The system of claim 1, wherein the transducer and the controller communicate asynchronously.

7. The system of claim 1, wherein the transducer is configured to selectively generate the electric field at multiple frequencies and the controller is further configured to select one of the multiple frequency channels as a receiving channel.

8. The system of claim 7, wherein the controller determines a signal-to-noise ratio for each frequency channel and selects the frequency channel having the highest signal-to-noise ratio as the receiving channel.

9. The system of claim 1, wherein the controller is further configured to transmit digital data to the transducer, and the transducer is configured to receive the digital data.

10. The system of claim 1, wherein the transducer is configured to generate the electric field at a first set of one or more frequencies and the controller is configured to detect the generated electric field at the first set of one or more frequencies,

wherein a second combination touch and transducer input system is provided, comprising a second transducer, a second array of electrodes, and a second controller, the second transducer being configured to generate an electric field at a second set of one or more frequencies different from the first set of one or more frequencies and the second controller being configured to detect the generated elected field at the second set of one or more frequencies.

11. The system of claim 1, wherein the controller is further configured to determine the position of the transducer by fitting at least some of the measured attributes of the plurality of sensing signals to a pre-determined parameterized curve.

12. The system of claim 1, wherein the array of electrodes comprises:

a first set of elongate electrodes arranged substantially in parallel with each other and extending in a first direction; and

a second set of elongate electrodes arranged substantially in parallel with each other and extending in a second direction that is different from the first direction;

wherein each pair of at least one of the first set of elongate electrodes and at least one of the second set of elongate electrodes forms a capacitor;

wherein the transducer and the array of electrodes are electrically coupled; and

wherein the controller is further configured to;

when operating in the touch mode, supply a signal to each of the first set of elongate electrodes, detect a capacitance change reflected in a signal outputted from each of the second set of elongate electrodes, and determine the position of the proximate object based on the detected capacitance change; and

when operating in the transducer mode, measure attributes of a plurality of sensing signals outputted from the first and second sets of elongate electrodes and calculate the position of the transducer based on the measured attributes.

13. The system of claim 12, wherein the controller is further configured to, when operating in the transducer mode:

measure an attribute of a sensing signal outputted from each of the first set of elongate electrodes while selectively terminating two or more of the first set of elongate electrodes that are adjacent to the elongate electrode being sensed, and

measure an attribute of a sensing signal outputted from each of the second set of elongate electrodes while selectively terminating two or more of the second set of elongate electrodes that are adjacent to the elongate electrode being sensed.

14. The system of claim 13, wherein the two or more of the first set of elongate electrodes that are adjacent to the elongate electrode being sensed are grounded, and the two or more of the second set of elongate electrodes that are adjacent to the elongate electrode being sensed are grounded.

15. The system of claim 13, wherein the two or more of the first set of elongate electrodes that are adjacent to the elongate electrode being sensed are floated, and the two or more of the second set of elongate electrodes that are adjacent to the elongate electrode being sensed are floated.

16. The system of claim 13, wherein the two or more of the first set of elongate electrodes that are adjacent to the elongate electrode being sensed are terminated via an impedance to ground, and the two or more of the second set of elongate electrodes that are adjacent to the elongate electrode being sensed are terminated via an impedance to ground.

17. The system of claim 1, wherein the controller is configured to alternate between operating in the touch mode and operating in the transducer mode in successive sampling periods of the system.

18. The system of claim 1, wherein the controller is configured to selectively divide the array of electrodes into a touch mode section and a transducer mode section, and to simultaneously operate in the touch mode in the touch mode section and in the transducer mode in the transducer mode section.

19. The system of claim 18, wherein the controller periodically switches the touch mode section and the transducer mode section such that a given point on the array of electrodes alternates between being in the touch mode section and being in the transducer mode section.

20. The system of claim 18, wherein the touch mode section includes a plurality of touch mode sub-sections and the transducer mode section includes a plurality of transducer mode sub-sections.

21. The system of claim 1, wherein the controller includes an amplifier selected from a group consisting of a charge amplifier, a voltage amplifier, a transimpedance amplifier, and a cascoded transimpedance amplifier, each being coupled to the array of electrodes and configured to amplify the plurality of sensing signals induced by the electric field in the array of electrodes.

22. The system of claim 1, wherein the transducer includes a capacitor or a battery configured to function as a power source for the transducer.

23. A method of selectively determining a position of a proximate object and a position of a transducer, the method comprising the steps of:

capacitively sensing the proximate object with an array of electrodes;

determining a position of the proximate object based on said capacitive sensing;

generating an electric field with the transducer;

transmitting digital data from the transducer;

inducing a plurality of sensing signals, based on the electric field, in a corresponding plurality of electrodes in the array of electrodes;

measuring attributes of the plurality of sensing signals;

determining a position of the transducer based on the measured attributes of the plurality of sensing signals; and

receiving the digital data with the array of electrodes.

24. The method of claim 23, wherein the step of generating an electric field with the transducer comprises selectively generating the electric field at multiple frequencies with the transducer, and the step of transmitting digital data with the transducer comprises encoding digital data in frequency shifts of the electric field for transmission.

25. The method of claim 23, wherein the data includes one or more of a pressure data, switch status data, and transducer identification data.

26. A cordless transducer configured for use with an array of electrodes, wherein the cordless transducer and the array of electrodes are capacitively coupled, the cordless transducer comprising:

a pen-shaped housing including a pen tip at its distal end;

a transducer controller arranged within the pen-shaped housing and configured to control the operation of the cordless transducer, the transducer controller including a pressure sensor configured to detect the pressure applied to the pen tip, the transducer controller further including a power storage device; and

an antenna coupled to the transducer controller to transmit the pressure sensor data, which is detected by the pressure sensor, as digital data to the array of electrodes;

wherein the power storage device supplies power to drive the transducer controller.

27. The cordless transducer of claim 26, wherein the power storage device comprises a battery.

28. The cordless transducer of claim 26, wherein the power storage device comprises a capacitor.

29. The cordless transducer of claim 28, wherein the capacitor is configured to be charged with power transmitted from a powering antenna.

30. The cordless transducer of claim 29, wherein the powering antenna is located on or near the array of electrodes.

31. The cordless transducer of claim 28, wherein the capacitor is configured to be charged when the cordless transducer is placed in a charging station.

32. The cordless transducer of claim 26, wherein the transducer controller is configured to awaken the cordless transducer from a sleep mode based on the pressure sensor data detected by the pressure sensor.

33. A combination touch and transducer input system, comprising:

(a) a cordless transducer configured to generate an electric field, the cordless transducer comprising;

(i) a pen-shaped housing including a pen tip at its distal end;

(ii) a transducer controller arranged within the pen-shaped housing and configured to control the operation of the cordless transducer, the transducer controller including a pressure sensor configured to detect the pressure applied to the pen tip, the transducer controller further including a power storage device; and

(iii) an antenna coupled to the transducer controller to transmit the pressure sensor data, which is detected by the pressure sensor, as digital data, wherein the power storage device supplies power to drive the transducer controller; and

(b) a sensor comprising;

(i) an array of electrodes; and

(ii) a sensor controller coupled to the array of electrodes, the sensor controller being configured to;

when operating in a touch mode, determine a position of a proximate object by capacitively sensing the object with the array of electrodes; and

when operating in a transducer mode, determine a position of the cordless transducer by measuring attributes of a plurality of sensing signals, the plurality of sensing signals being induced in the array of electrodes by the electric field generated by the cordless transducer;

wherein the sensor is configured to receive the pressure sensor data as digital data from the cordless transducer.

34. The combination touch and transducer input system of claim 33, wherein the power storage device of the cordless transducer comprises a capacitor, and the system further comprises a charging station that is configured to charge the capacitor when the cordless transducer is placed in the charging station.

35. The combination touch and transducer input system of claim 33, wherein the array of electrodes is formed on a single layer without substantially overlapping with each other.

36. A combination touch and transducer input system, comprising:

a transducer configured to generate an electric field;

an array of electrodes, and

a controller coupled to the array of electrodes, the controller being configured to;

when operating in a touch mode, determine a position of a proximate object by capacitively sensing the object with the array of electrodes; and

when operating in a transducer mode, determine a position of the transducer by measuring attributes of a plurality of sensing signals, the plurality of sensing signals being induced in the array of electrodes by the electric field generated by the transducer,

wherein the controller is further configured to determine the position of the transducer by fitting at least some of the measured attributes of the plurality of sensing signals to a pre-determined parameterized curve, the pre-determined parameterized curve relating a plurality of positions of the transducer relative to one electrode with a plurality of attributes of sensing signals induced in that electrode by the transducer at the plurality of positions, respectively.

37. The system of claim 36, wherein the pre-determined parameterized curve is empirically derived for use with the transducer having a tip shape and the array of electrodes having an electrode configuration pattern.

38. The system of claim 36, wherein the pre-determined parameterized curve includes one or more of a position parameter, a height parameter, and a tilt parameter.

39. The system of claim 36, further comprising an external processor, wherein the controller and the external processor are configured to perform the fitting of at least some of the measured attributes of the plurality of sensing signals to a pre-determined parameterized curve in distributed processing.

40. A combination touch and transducer input system, comprising:

a transducer configured to generate an electric field;

an array of electrodes, and

a controller coupled to the array of electrodes, the controller being configured to;

when operating in a touch mode, determine a position of a proximate object by capacitively sensing the object with the array of electrodes; and

when operating in a transducer mode, determine a position of the transducer by measuring attributes of a plurality of sensing signals, the plurality of sensing signals being induced in the array of electrodes by the electric field generated by the transducer,

wherein the controller is further configured to determine the position of the transducer by fitting at least some of the measured attributes of the plurality of sensing signals to a pre-determined parameterized curve, the pre-determined parameterized curve including a position parameter and at least one or more of a height parameter and a tilt parameter.

41. The system of claim 40, wherein the pre-determined parameterized curve is empirically derived for use with the transducer having a tip shape and the array of electrodes having an electrode configuration pattern.

42. The system of claim 40, further comprising an external processor, wherein the controller and the external processor are configured to perform the fitting of at least some of the measured attributes of the plurality of sensing signals to a pre-determined parameterized curve in distributed processing.

43. A combination touch and transducer input system, comprising:

a transducer configured to generate an electric field;

an array of electrodes; and

a controller coupled to the array of electrodes, the controller being configured to;

when operating in a touch mode, determine a position of a proximate object by capacitively sensing the object with the array of electrodes; and

when operating in a transducer mode, determine a position of the transducer by measuring attributes of a plurality of sensing signals, the plurality of sensing signals being induced in the array of electrodes by the electric field generated by the transducer;

wherein the controller includes a cascoded transimpedance amplifier coupled to the array of electrodes, the cascoded transimpedance amplifier being configured to amplify the plurality of sensing signals induced by the electric field in the array of electrodes.