US-20260126875-A1 - SENSOR CONTROLLER, ELECTRONIC APPARATUS, AND POSITION DETECTION METHOD

US20260126875A1US 20260126875 A1US20260126875 A1US 20260126875A1US-20260126875-A1

Abstract

A sensor controller is provided, which is configured to be connected to a capacitive touch sensor having a plurality of sensor electrodes arranged planarly. The sensor controller includes a scan controller that executes a plurality of types of operation modes in which a pen scan for detecting an active pen transmitting a downlink signal and a touch scan for detecting a passive pointer not transmitting the downlink signal are repeatedly executed on a time-sharing basis via the plurality of sensor electrodes. The sensor controller includes a signal transmitter that transmits, during execution of the pen scan, an uplink signal for requesting the downlink signal via the plurality of sensor electrodes. When the passive pointer is not detected by the touch scan, the signal transmitter makes a transmission frequency of the uplink signal lower than when the passive pointer is detected by the touch scan.

Inventors

Yoshio Nomura
Masayuki Miyamoto

Assignees

WACOM CO., LTD.

Dates

Publication Date: 20260507
Application Date: 20251230
Priority Date: 20230718

Claims (13)

1 . A sensor controller connected to a capacitive touch sensor having a plurality of sensor electrodes arranged planarly, the sensor controller comprising: a scan controller that executes a plurality of types of operation modes, in which a pen scan for detecting an active pen transmitting a downlink signal and a touch scan for detecting a passive pointer not transmitting the downlink signal are repeatedly executed on a time-sharing basis via the plurality of sensor electrodes; and a signal transmitter that transmits, during execution of the pen scan, an uplink signal for requesting the downlink signal, via the plurality of sensor electrodes, wherein, when the passive pointer is not detected by the touch scan, the signal transmitter makes a transmission frequency of the uplink signal lower than when the passive pointer is detected by the touch scan.
2 . The sensor controller according to claim 1 , wherein the plurality of types of operation modes include: a first mode in which a time slot for the touch scan is assigned to a first touch time length and a time slot for the pen scan is assigned to a first pen time length, and a second mode in which a time slot for the touch scan is assigned to a second touch time length and a time slot for the pen scan is assigned to a second pen time length, and the scan controller selectively executes the first mode when the passive pointer is detected and selectively executes the second mode when the passive pointer is not detected.
3 . The sensor controller according to claim 2 , wherein the second touch time length is given by subtracting a predetermined value from the first touch time length, and the second pen time length is given by adding the predetermined value to the first pen time length.
4 . The sensor controller according to claim 3 , wherein, when the number of transmissions of the uplink signal per unit time in the first mode is defined as a first transmission rate and the number of transmissions of the uplink signal per unit time in the second mode is defined as a second transmission rate, a product of the second pen time length and the second transmission rate is smaller than a product of the first pen time length and the first transmission rate.
5 . The sensor controller according to claim 1 , wherein the pen scan is a global scan for detecting the active pen over an entire sensor region provided by the touch sensor.
6 . The sensor controller according to claim 1 , wherein, when the passive pointer is not detected by the touch scan, the signal transmitter makes: a transmission voltage of the uplink signal lower, the number of the sensor electrodes used for transmitting the uplink signal smaller, or an orthogonal code sequence for encoding the uplink signal shorter, than when the passive pointer is detected by the touch scan.
7 . The sensor controller according to claim 1 , further comprising: a signal acquisition circuitry that receives and acquires the downlink signal from the plurality of sensor electrodes during execution of the pen scan, wherein, when the passive pointer is not detected by the touch scan, the signal acquisition circuitry makes a reception frequency of the downlink signal lower than when the passive pointer is detected by the touch scan.
8 . The sensor controller according to claim 1 , wherein, when a specific condition is met, the signal transmitter makes: the transmission frequency of the uplink signal higher, a transmission voltage of the uplink signal higher, the number of the sensor electrodes used for transmitting the uplink signal larger, or an orthogonal code sequence used for encoding the uplink signal longer, than when the specific condition is not met.
9 . The sensor controller according to claim 8 , wherein the specific condition includes: a condition under which disconnection of at least one of the sensor electrodes is detected, a condition under which an operation mode for detecting the passive pointer not transmitting the downlink signal is being executed by the scan controller, or a condition under which an operation mode for detecting the passive pointer in a special state is being executed by the scan controller.
10 . The sensor controller according to claim 1 , wherein, when the active pen meets a proximity condition indicative of a state in which the active pen is either close to or in contact with the touch sensor, the signal transmitter either changes a transmission voltage of the uplink signal or changes a length of an orthogonal code sequence used for encoding the uplink signal, in accordance with a tilt angle of the active pen.
11 . An electronic device comprising: a capacitive touch sensor having a plurality of sensor electrodes arranged planarly; and a sensor controller connected to the touch sensor, the sensor controller including: a scan controller that executes a plurality of types of operation modes in which a pen scan for detecting an active pen transmitting a downlink signal and a touch scan for detecting a passive pointer not transmitting the downlink signal are repeatedly executed on a time-sharing basis via the plurality of sensor electrodes, a signal transmitter that transmits, during execution of the pen scan, an uplink signal for requesting the downlink signal, via the plurality of sensor electrodes, and when the passive pointer is not detected by the touch scan, the signal transmitter making a transmission frequency of the uplink signal lower than when the passive pointer is detected by the touch scan.
12 . A position detection method comprising: using a sensor controller connected to a capacitive touch sensor having a plurality of sensor electrodes arranged planarly; repeatedly executing, on a time-sharing basis via the plurality of sensor electrodes, a pen scan for detecting an active pen transmitting a downlink signal and a touch scan for detecting a passive pointer not transmitting the downlink signal; and transmitting, during execution of the pen scan, an uplink signal for requesting the downlink signal, via the plurality of sensor electrodes, wherein, in the transmitting, when the passive pointer is not detected by the touch scan, a transmission frequency of the uplink signal is made lower than when the passive pointer is detected by the touch scan.
13 .- 22 . (canceled)

Description

BACKGROUND Technical Field The present disclosure relates to a sensor controller, an electronic apparatus, and a position detection method. Description of the Related Art Conventionally, there have been known position detection systems each including an active electronic pen (also simply referred to as an “active pen” hereunder), which is a position indicator with a built-in battery, and an electronic device having a touch sensor. In this type of system, two types of signals are transmitted and received between the active pen and the electronic device so as to synchronize data exchanges and controls therebetween. Of the two distinct types of signals, one from the electronic device is called an “uplink signal,” and the other from the active pen is called a “downlink signal.” JP2021/043640 discloses a touch controller operating in an uplink power-saving mode and a normal mode. Upon receipt of a suspend instruction from a host computer, the touch controller operates in the uplink power-saving mode in which power is saved for transmitting the uplink signal. Upon detecting a predetermined trigger while operating in the uplink power-saving mode, the touch controller returns to the normal mode. However, the touch controller disclosed in JP2021/043640 fails to transition from the normal mode to the power-saving mode in a case where the host computer is for some reason unable to transmit the suspend instruction. BRIEF SUMMARY The present disclosure has been made in view of the above circumstances and provides, as an object, a sensor controller, an electronic device, and a position detection method for spontaneously saving power in detecting a pointed position, in accordance with detection conditions of a touch sensor. According to a first aspect of the present disclosure, there is provided a sensor controller connected to a capacitive touch sensor having a plurality of sensor electrodes arranged planarly. The sensor controller includes a scan controller that executes a plurality of types of operation modes. In those operation modes, a pen scan for detecting an active pen transmitting a downlink signal and a touch scan for detecting a passive pointer not transmitting the downlink signal are repeatedly executed on a time-sharing basis via the plurality of sensor electrodes and a signal transmitter transmits, during execution of the pen scan, an uplink signal for requesting the downlink signal, via the plurality of sensor electrodes. When the passive pointer is not detected by the touch scan, the signal transmitter makes a transmission frequency of the uplink signal lower than when the passive pointer is detected by the touch scan. According to a second aspect of the present disclosure, there is provided an electronic device including a capacitive touch sensor having a plurality of sensor electrodes arranged planarly and a sensor controller connected to the above-mentioned touch sensor. According to a third aspect of the present disclosure, there is provided a position detection method using a sensor controller connected to a capacitive touch sensor having a plurality of sensor electrodes arranged planarly. The position detection method includes, by the sensor controller, repeatedly executing, on a time-sharing basis via the plurality of sensor electrodes, a pen scan for detecting an active pen transmitting a downlink signal and a touch scan for detecting a passive pointer not transmitting the downlink signal as well as transmitting, during execution of the pen scan, an uplink signal for requesting the downlink signal, via the plurality of sensor electrodes. In the transmitting, when the passive pointer is not detected by the touch scan, a transmission frequency of the uplink signal is made lower than when the passive pointer is detected by the touch scan. According to a fourth aspect of the present disclosure, there is provided a sensor controller connected to a capacitive touch sensor having a plurality of sensor electrodes arranged planarly. The sensor controller includes a detection processor that repeatedly executes a touch scan for detecting a passive pointer not transmitting any signal via the plurality of sensor electrodes, The touch scan includes a specific drive operation and a drive change circuitry that changes a drive parameter related to the specific drive operation in such a manner that, when the passive pointer is not detected by the touch scan, either an execution frequency of the specific drive operation is made lower or an execution amount of the specific drive operation is made smaller than when the passive pointer is detected by the touch scan. According to a fifth aspect of the present disclosure, there is provided an electronic device including a capacitive touch sensor having a plurality of sensor electrodes arranged planarly and a sensor controller connected to the above-mentioned touch sensor. According to a sixth aspect of the present disclosure, there is provided a position detection method