Method of transmitting transmission data from sensor controller to pen, and pen
A method is provided for transmitting transmission data from a sensor controller that detects a pen to the pen through a sensor electrode group. The pen includes a pen tip electrode arranged near a pen tip, and an analog circuit that detects edges of a signal led to the pen tip electrode. The pen also includes a digital circuit that performs a correlation operation of an output signal of the analog circuit and known patterns to detect the transmission data. The sensor controller is configured to generate a pulse signal representing the transmission data. The sensor controller is configured to transmit the pulse signal, by using a main signal and a sub signal of the pulse signal so as to enhance the edges, thereby transmitting the transmission data through the sensor electrode group.
1. A system, comprising:
a sensor controller configured to
generate a pulse signal representing transmission data, and
transmit the pulse signal, by using a main signal and a sub signal of the pulse signal so as to enhance edges, thereby transmitting the transmission data via a sensor electrode group; and
a pen including
a pen tip electrode arranged near a pen tip,
an analog circuit that detects edges of a signal led to the pen tip electrode,
a pattern storage that stores a plurality of chip sequences as known patterns, and
a digital circuit that performs a correlation operation of an output signal of the analog circuit and the known patterns to recognize the transmission data.
2. The system according to claim 1 , wherein
the sub signal is a delay signal of the pulse signal, and
the sensor controller transmits a mixed signal of the main signal and the sub signal to transmit the pulse signal.
3. The system according to claim 2 , wherein
the sensor controller uses a spread code, in which a time length of one chip is a predetermined chip length, to spread the transmission data to thereby acquire the pulse signal, and
the mixed signal is a signal including an even number of corresponding edges in a time shorter than a half the predetermined chip length starting at each edge of the pulse signal.
4. The system according to claim 3 , wherein
the mixed signal includes return edges in an opposite direction of the corresponding edges in a time shorter than the half the predetermined chip length starting at each edge of the pulse signal, and
a slope of the return edge is gentler than a slope of each edge of the pulse signal.
5. The system according to claim 1 , wherein
the sensor electrode group includes a plurality of sensor electrodes, and
the sensor controller transmits the main signal and the sub signal from the sensor electrodes different from each other to transmit the pulse signal.
6. The system according to claim 1 , wherein
the sensor electrode group includes a plurality of first sensor electrodes arranged in a first layer and a plurality of second sensor electrodes arranged in a second layer, and
the sensor controller transmits the main signal from at least part of the plurality of first sensor electrodes and transmits the sub signal from at least part of the plurality of second sensor electrodes to thereby transmit the pulse signal.
7. The system according to claim 6 , wherein each of the plurality of first sensor electrodes is an electrode supplied with potential necessary for driving a pixel of a display apparatus.
8. The system according to claim 1 , wherein
the sensor electrode group includes a plurality of first sensor electrodes and a plurality of second sensor electrodes arranged at positions not overlapping the plurality of first sensor electrodes in plan view, and
the sensor controller is configured to transmit the main signal through the plurality of first sensor electrodes and transmit a reverse-phase signal of the main signal through the plurality of second sensor electrodes.
9. The system according to claim 1 , wherein the pen is a first pen that applies a correlation operation with relatively coarse granularity to the output signal of the analog circuit or a second pen that applies a correlation operation with relatively fine granularity to the output signal of the analog circuit.
10. The system according to claim 1 , wherein the chip sequences as the known patterns are obtained by applying Manchester coding to spread codes used to transmit the transmission data.
11. The system according to claim 10 , wherein the digital circuit includes a shift register configured to store the output signal of the analog circuit, and the digital circuit calculates a correlation between a chip sequence stored in the shift register and the known patterns stored in the pattern storage, respectively.
12. The system according to claim 11 , wherein the digital circuit, when a calculated correlation result for one of the known patterns is equal to or greater than a predetermined value, determines that the spread code corresponding to the known pattern is recognized.