Combination touch and transducer input system and method
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.
1. A sensor controller to control operation of a sensor,
wherein the sensor includes an array of electrodes arranged to define a sensor surface; and
wherein the sensor is configured for use with a pen-shaped transducer, the pen-shaped transducer being capable of generating an electric field which is used by the sensor to detect a position indicated by the pen-shaped transducer on the sensor surface;
the sensor controller comprising:
frequency selection circuitry which, in operation, selects a frequency out of multiple frequencies to avoid noisy frequencies, the selected frequency being for use by the pen-shaped transducer to generate the electric field; and
pen-and-touch position detection circuitry which, in operation,
executes touch detection processing including supplying defined signals to the array of electrodes and measuring attributes of signals detected by the array of electrodes to capacitively detect an object on or adjacent to the sensor surface, and
executes transducer detection processing including detecting a position indicated by the pen-shaped transducer on the sensor surface based on capacitive coupling between the array of electrodes and the pen-shaped transducer generating the electric field at the selected frequency;
wherein the sensor controller is further configured to transmit information regarding the selected frequency to the pen-shaped transducer.
2. The sensor controller of claim 1 , wherein the frequency selection circuitry compares signal-to-noise ratios of the multiple frequencies and selects a frequency having a highest signal-to-noise ratio.
3. The sensor controller of claim 1 , wherein the frequency selection circuitry selects a frequency out of the multiple frequencies to avoid a frequency of a signal radiated from a display screen.
4. The sensor controller of claim 1 , which transmits the information regarding the selected frequency to the pen-shaped transducer via the capacitive coupling between the array of electrodes and the pen-shaped transducer.
5. The sensor controller of claim 1 , further comprising a RF communication circuitry which, in operation, establishes an RF wireless channel with the pen-shaped transducer and transmits the information regarding the selected frequency to the pen-shaped transducer over the RF wireless channel.
6. The sensor controller of claim 5 , wherein the RF communication circuitry is in compliance with Bluetooth® communications standards.
7. The sensor controller of claim 5 , which receives at least one of transducer ID information, pressure information indicative of pressure applied to a tip of the pen-shaped transducer, or switch information indicative of an operation state of a switch provided on the pen-shaped transducer, from the pen-shaped transducer over the RF wireless channel.
8. The sensor controller of claim 1 , which is further configured to transmit at least one of sensor ID information or sensor operation mode information to the pen-shaped transducer.
9. The sensor controller of claim 8 , wherein the sensor operation mode information indicates a first mode corresponding to the touch detection processing and a second mode corresponding to the transducer detection processing.
10. The sensor controller of claim 1 , wherein the capacitively detected object is a finger.
11. A method executed in a pen-and-touch sensor to detect a position indicated by a pen-shaped transducer and a position indicated by an object,
wherein the sensor includes an array of electrodes arranged to define a sensor surface; and
wherein the pen-shaped transducer generates an electric field which is used by the sensor to detect a position indicated by the pen-shaped transducer on the sensor surface;
the method comprising:
selecting a frequency out of multiple frequencies to avoid noisy frequencies, the selected frequency being for use by the pen-shaped transducer to generate the electric field;
transmitting information regarding the selected frequency to the pen-shaped transducer;
detecting a position indicated by the pen-shaped transducer on the sensor surface based on capacitive coupling between the array of electrodes and the pen-shaped transducer generating the electric field at the selected frequency; and
supplying defined signals to the array of electrodes and measuring attributes of signals detected by the array of electrodes to capacitively detect an object on or adjacent to the sensor surface.
12. The method of claim 11 , comprising:
establishing an RF wireless channel with the pen-shaped transducer and transmitting the information regarding the selected frequency to the pen-shaped transducer over an RF wireless channel.
13. The method of claim 12 , wherein the RF wireless channel is established in compliance with Bluetooth® communication standards.
14. The method of claim 12 , comprising:
receiving at least one of transducer ID information, pressure information indicative of pressure applied to a tip of the pen-shaped transducer, or switch information indicative of an operation state of a switch provided on the pen-shaped transducer, from the pen-shaped transducer over the RF wireless channel.
15. The method of claim 11 , comprising:
transmitting at least one of sensor ID information or sensor operation mode information to the pen-shaped transducer.
16. A non-transitory computer-readable medium including computer-executable instructions which, when loaded onto a sensor controller, performs a sensor control operation of controlling operation of a pen-and-touch sensor to detect a position indicated by a pen-shaped transducer and a position indicated by an object,
wherein the sensor includes an array of electrodes arranged to define a sensor surface; and
wherein the pen-shaped transducer generates an electric field which is used by the sensor to detect a position indicated by the pen-shaped transducer on the sensor surface;
the sensor control operation comprising:
selecting a frequency out of multiple frequencies to avoid noisy frequencies, the selected frequency being for use by the pen-shaped transducer to generate the electric field;
transmitting information regarding the selected frequency to the pen-shaped transducer;
detecting a position indicated by the pen-shaped transducer on the sensor surface based on capacitive coupling between the array of electrodes and the pen-shaped transducer generating the electric field at the selected frequency; and
supplying defined signals to the array of electrodes and measuring attributes of signals detected by the array of electrodes to capacitively detect an object on or adjacent to the sensor surface.
17. The non-transitory computer-readable medium of claim 16 , wherein the sensor control operation comprises:
establishing an RF wireless channel with the pen-shaped transducer and transmitting the information regarding the selected frequency to the pen-shaped transducer over the RF wireless channel.
18. The non-transitory computer-readable medium of claim 17 , wherein the RF wireless channel is established in compliance with Bluetooth® communication standards.
19. The non-transitory computer-readable medium of claim 17 , wherein the sensor control operation comprises:
receiving at least one of transducer ID information, pressure information indicative of pressure applied to a tip of the pen-shaped transducer, or switch information indicative of an operation state of a switch provided on the pen-shaped transducer, from the pen-shaped transducer over the RF wireless channel.
20. The non-transitory computer-readable medium of claim 16 , wherein the sensor control operation comprises:
transmitting at least one of sensor ID information or sensor operation mode information to the pen-shaped transducer.