# US 2018/0024654 A1 · Method in which active stylus and sensor controller are used, system, sensor controller, and active stylus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0024654 A1 - Document ID: US20180024654A1 - Status: Published application - Kind: A1 - Application number: 15/698,359 - Filed: 2017-09-07 - Published: 2018-01-25 - Earliest claimed: 2015-04-09 - Assignees: Wacom Co., Ltd. - Applicants: Wacom Co., Ltd. - Inventors: Takeshi Koike; Hideyuki Hara - Web page: https://patentgrep.com/patent/US20180024654A1 ## CPC - G06F 3/04162: {for exchanging data with external devices, e.g. smart pens, via the digitiser sensing hardware} - G06F 3/03: Arrangements for converting the position or the displacement of a member into a coded form - G06F 3/03545: {Pens or stylus} - G06F 3/0383: {Signal control means within the pointing device} - G06F 3/041: Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means - G06F 3/0412: {Digitisers structurally integrated in a display} - 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} - G06F 3/0442: {using active external devices, e.g. active pens, for transmitting changes in electrical potential to be received by the digitiser} - G09G 3/20: for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix {no fixed position being assigned to or needed to be assigned to the individual characters or partial characters} - G06F 2203/0384: Wireless input, i.e. hardware and software details of wireless interface arrangements for pointing devices - G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)} - G09G 2310/061: for resetting or blanking - G09G 2310/08: Details of timing specific for flat panels, other than clock recovery - G09G 2330/06: Handling electromagnetic interferences [EMI], covering emitted as well as received electromagnetic radiation - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract A method in which a sensor controller is connected to a sensor having an electrode group provided together with a display panel configured to operate in during a variable refresh cycle among a plurality of refresh cycles, and an active stylus performs bidirectional communication with the sensor controller. According to the method, the sensor controller acquires a present refresh cycle among the plurality of refresh cycles of the display panel, generates an uplink signal, which serves as a reference for synchronization corresponding to the acquired present refresh cycle, and transmits the uplink signal to the active stylus, which is not detected as yet or is detected already, at the present refresh cycle. ## Claims ### Claim 1 A method in which a sensor controller connected to a sensor having an electrode group provided together with a display panel configured to operate in a variable refresh cycle among a plurality of refresh cycles, and an active stylus that performs bidirectional communication with the sensor controller are used, the method comprising: acquiring, by the sensor controller, a present refresh cycle among the plurality of refresh cycles of the display panel; generating, by the sensor controller, an uplink signal, which serves as a reference for synchronization corresponding to the acquired present refresh cycle; and transmitting the uplink signal to the active stylus, which is not detected as yet or is detected already, at the present refresh cycle. ### Claim 2 (depends on 1) The method according to claim 1, wherein the uplink signal designates, to the active stylus, a time point at which the downlink signal is to be transmitted with reference to the uplink signal. ### Claim 3 (depends on 1) The method according to claim 1, wherein the refresh cycle has a time length corresponding to an image frame time period. ### Claim 4 (depends on 1) The method according to claim 1, wherein: one or more blank periods are within one cycle of the refresh cycle, and the sensor controller uses at least one of the one or more blank periods as a first blank period within which the uplink signal is transmitted. ### Claim 5 (depends on 4) The method according to claim 4, wherein each of the one or more blank periods is a period within which noise generated from the display panel is sparse in comparison with that in periods of the refresh cycle other than the one or more blank periods. ### Claim 6 (depends on 4) The method according to claim 4, wherein: part of the electrode group is a commonly used electrode that is used commonly with an electrode of the display panel, and during each of the one or more blank periods a potential of the commonly used electrode is not utilized for driving of pixels of the display panel. ### Claim 7 (depends on 6) The method according to claim 6, wherein the sensor controller uses, from among the one or more blank periods, one blank period that is positioned first in one frame corresponding to an image frame as the first blank period. ### Claim 8 (depends on 6) The method according to claim 6, wherein: a plurality of blank periods is included within the refresh cycle, the method further comprises transmitting, by the active stylus, the downlink signal to the sensor controller, and at least one of the plurality of blank periods other than the at least one of the one or more blank periods used as the first blank period is used as a second blank period within which the active stylus transmits the downlink signal. ### Claim 9 (depends on 8) The method according to claim 8, wherein the blank periods are arranged at equal intervals within the refresh cycle. ### Claim 10 (depends on 8) The method according to claim 8, wherein: the uplink signal includes a command that designates data to be transmitted by the active stylus, and the downlink signal includes the data designated by the command. ### Claim 11 (depends on 8) The method according to claim 8, further comprising: transmitting, by the sensor controller, an auxiliary uplink signal within at least some of the plurality of blank periods, wherein the active stylus starts transmission of the downlink signal in response to reception of the auxiliary uplink signal. ### Claim 12 (depends on 11) The method according to claim 11, wherein the uplink signal includes data indicative of whether the sensor controller transmits the auxiliary uplink signal. ### Claim 13 (depends on 8) The method according to claim 8, wherein: the downlink signal indicates a writing pressure; and the transmitting of the downlink signal includes transmitting the downlink signal indicating the writing pressure at fixed time intervals. ### Claim 14 (depends on 8) The method according to claim 8, wherein, the transmitting of the downlink signal includes transmitting a position signal within N (N>0) of the one or more second blank periods, and transmitting a data signal that varies depending upon an operation state of the active stylus within M (M>0) of the one or more second blank periods. ### Claim 15 (depends on 14) The method according to claim 14, wherein the data signal includes an identifier allocated to the active stylus. ### Claim 16 (depends on 8) The method according to claim 8, further comprising: detecting, by the sensor controller, the active stylus by receiving the downlink signal, wherein the sensor controller updates a number of the blank periods used as the first blank period in response to whether the active stylus is detected. ### Claim 17 A system comprising: a sensor controller connected to a sensor having an electrode group provided together with a display panel configured to operate in a variable refresh cycle among a plurality of refresh cycles; and an active stylus that, in operation, performs bidirectional communication with the sensor controller, wherein: the sensor controller, in operation, transmits an uplink signal, which serves as a reference for synchronization corresponding to a present refresh cycle among the plurality of refresh cycles of the display panel and serves as a reference that designates a time point at which the active stylus is to transmit a downlink signal, to the active stylus that is not detected as yet or is detected already at in the present refresh cycle, the active stylus, in operation, detects the uplink signal, transmits the downlink signal at the time point designated by the detected uplink signal, and the sensor controller, in operation, detects the active stylus by detecting the downlink signal. ### Claim 18 A sensor controller that is connected to a sensor having an electrode group provided together with a display panel configured to operate in a variable refresh cycle among a plurality of refresh cycles and performs bidirectional communication with an active stylus, the sensor controller comprising: a transmission circuit; and a control circuit that, in operation, specifies a present refresh cycle among the plurality of refresh cycles of the display panel and causes the transmission circuit to transmit, to the active stylus, an uplink signal, which serves as a reference for synchronizing a transmission of a downlink signal in correspondence to the specified present refresh cycle. ### Claim 19 (depends on 18) The sensor controller according to claim 18, wherein: part of the electrode group is a commonly used electrode that is commonly used together with an electrode of the display panel, and the uplink signal includes information indicative of a blank period, within which a potential of the commonly used electrode is not utilized for driving of pixels of the display panel, within the refresh cycle. ### Claim 20 (depends on 19) The sensor controller according to claim 19, wherein the blank period corresponds to a vertical blanking period of the display panel. ### Claim 21 (depends on 19) The sensor controller according to claim 19, wherein the blank period corresponds to a horizontal blanking period of the display panel included in the refresh cycle. ### Claim 22 An active stylus that performs bidirectional communication with a sensor controller connected to a sensor having an electrode group provided together with a display panel configured to operate in a variable refresh cycle among a plurality of refresh cycles, the active stylus comprising: a reception circuit that, in operation, receives from the sensor controller an uplink signal that serves as a reference for synchronization and that is transmitted repetitively at a present refresh cycle among the plurality of refresh cycles of the display panel; and a transmission circuit that, in operation, transmits a downlink signal to the sensor controller at a time point designated by the uplink signal. ### Claim 23 (depends on 22) The active stylus according to claim 22, wherein: part of the electrode group is a commonly used electrode that is used commonly with an electrode of the display panel, the uplink signal includes information indicative of an arrangement within the refresh cycle of a plurality of blank periods within which a potential of the commonly used electrode is not utilized for driving of pixels of the display panel and a command identifying data to be transmitted within each of the plurality of blank periods, and the transmission circuit transmits the downlink signal to the sensor controller based on the data to be transmitted that is identified by the command at each timing that is indicated as a blank period by an auxiliary uplink signal transmitted within each of the plurality of blank periods. ### Claim 24 (depends on 23) The active stylus according to claim 23, wherein: the display panel includes a plurality of blank periods including one or more first blank periods and one or more second blank periods within one cycle of the refresh cycle, the uplink signal is transmitted in the first blank periods, and the downlink signal is transmitted in the second blank periods. ### Claim 25 (depends on 24) The active stylus according to claim 24, wherein each of the plurality of blank periods corresponds to a horizontal blanking period of the display panel. ### Claim 26 (depends on 24) The active stylus according to claim 24, wherein: the sensor controller transmits, within at least some of the one or more second blank periods, an auxiliary uplink signal that has a small time length in comparison with that of the uplink signal and that indicates each of the second blank periods, and the transmission circuit starts transmission of the downlink signal within each of the second blank periods in response to reception of the auxiliary uplink signal.