Patent ID: 12242691

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described in detail below with reference to the drawings.

FIG.1is a diagram illustrating an external appearance of an electronic device1according to a first embodiment of the present disclosure. A stylus P and a finger F to be detected by the electronic device1are also illustrated in this figure.FIG.2is a diagram illustrating a configuration of a sensor system3, which is disposed in the electronic device1to detect the stylus P and the finger F.

As illustrated inFIG.1, the electronic device1includes a first housing10and a second housing20, which are connected to each other by a connecting portion2. The connecting portion2includes a hinge and a flexible substrate. The first housing10is configured to be rotatable through 360° around the connecting portion2as denoted by an illustrated dashed arrow A. The flexible substrate is a substrate configured to deform at an angle corresponding to relative positions of the first housing10and the second housing20. In the flexible substrate, wires are arranged for connecting between wires in the first housing10and wires in the second housing20.

The first housing10has a first panel surface11, and the second housing20has a second panel surface21. The surface of each of the first panel surface11and the second panel surface21is flat. A user can slide a pen tip of the stylus P and the finger F on the surfaces of the first panel surface11and the second panel surface21. Further, the first panel surface11and the second panel surface21are each disposed on a surface of the corresponding housing such that the first panel surface11and the second panel surface21face the same direction when the first housing10is set at a 180° position. Both the first panel surface11and the second panel surface21have a rectangular shape and are disposed such that their respective long-side directions are perpendicular to a direction in which the first panel surface11and the second panel surface21are aligned when the first housing10is set at the 180° position.

Here, each of the first panel surface11and the second panel surface21may or may not serve as a display surface for display. As specific systems to make each of the first panel surface11and the second panel surface21function as the display surface of the display, an in-cell system, an on-cell system, an out-cell system, or any other various systems can be employed. In the case of the in-cell system, part of electrodes for driving pixels in the display (e.g., common electrodes of a liquid-crystal display) function as part of sensor electrode groups to be described later (e.g., a plurality of sensor electrodes12xor a plurality of sensor electrodes22xto be described later). In the case of the on-cell system, although the sensor electrode groups to be described later are disposed in the display, the sensor electrode groups are disposed separately from the electrodes for driving the pixels in the display. In the case of the out-cell system, the sensor electrode groups to be described later are disposed on a display panel. In cases where both the first panel surface11and the second panel surface21serve as the display surfaces of the displays, the electronic device1functions as the dual-screen model described above.

Referring now toFIG.2, the sensor system3includes first sensor electrode groups12xand12y, a first integrated circuit13, first lead-out wires (lines/traces)14xand14y, second sensor electrode groups22xand22y, a second integrated circuit23, second lead-out wires (lines/traces)24xand24y, and a host processor30. Of these, the first sensor electrode groups12xand12y, the first integrated circuit13, and the first lead-out wires14xand14yare disposed in the first housing10, while the second sensor electrode groups22xand22y, the second integrated circuit23, the second lead-out wires24xand24y, and the host processor30are disposed in the second housing20. It is noted that, although the host processor30is disposed in the second housing20, this arrangement is a mere example and the host processor30may be disposed in the first housing10.

As illustrated inFIG.2, the first integrated circuit13and the second integrated circuit23are connected to each other via a wire (line/trace)31. Further, the first integrated circuit13and the second integrated circuit23are connected to the host processor30via wires (lines/traces)32and33, respectively. Part of the wires31and32extend into the above-described flexible substrate. It is noted that, although each of the wires31to33is depicted by a single line inFIG.2, each of the wires31to33is a set of multiple wires in actual implementation.

The first sensor electrode groups12xand12yare disposed inside the first panel surface11as also illustrated inFIG.1. Similarly, the second sensor electrode groups22xand22yare disposed inside the second panel surface21. The first sensor electrode groups12xand12yrespectively include the plurality of sensor electrodes12xand a plurality of sensor electrodes12y. The plurality of sensor electrodes12x, each of which extends along a long-side direction of the first panel surface11, are arranged at equal intervals along a short-side direction of the first panel surface11. The plurality of sensor electrodes12y, each of which extends along the short-side direction of the first panel surface11, are arranged at equal intervals along the long-side direction of the first panel surface11. Further, the second sensor electrode groups22xand22yrespectively include the plurality of sensor electrodes22xand a plurality of sensor electrodes22y. The plurality of sensor electrodes22x, each of which extends along a long-side direction of the second panel surface21, are arranged at equal intervals along a short-side direction of the second panel surface21. The plurality of sensor electrodes22y, each of which extends along the short-side direction of the second panel surface21, are arranged at equal intervals along the long-side direction of the second panel surface21.

The first integrated circuit13is connected to each sensor electrode12xvia the corresponding one of the first lead-out wires14x. The first lead-out wires14xare arranged so as to correspond one-to-one to the sensor electrodes12x. The first integrated circuit13is also connected to each sensor electrode12yvia the corresponding one of the first lead-out wires14y. The first lead-out wires14yare arranged so as to correspond one-to-one to the sensor electrodes12y. Similarly, the second integrated circuit23is connected to each sensor electrode22xvia the corresponding one of the second lead-out wires24x.

The second lead-out wires24xare arranged so as to correspond one-to-one to the sensor electrodes22x. The second integrated circuit23is also connected to each sensor electrode22yvia the corresponding one of the second lead-out wires24y. The second lead-out wires24yare arranged so as to correspond one-to-one to the sensor electrodes22y.

The first integrated circuit13has a function of detecting the stylus P and the finger F present on the first panel surface11, a function of deriving the position of the detected stylus P or finger F within the first panel surface11and supplying position data indicating the derived position to the host processor30, and a function of bidirectionally transmitting and receiving signals to and from the stylus P via the first sensor electrode groups12xand12y. Similarly, the second integrated circuit23has a function of detecting the stylus P and the finger F present on the second panel surface21, a function of deriving the position of the detected stylus P or finger F within the second panel surface11and supplying position data indicating the derived position to the host processor30, and a function of bidirectionally transmitting and receiving signals to and from the stylus P via the second sensor electrode groups22xand22y. The first integrated circuit13and the second integrated circuit23are configured to execute these functions in synchronization with each other, either under the control of the host processor30or by communicating with each other via the wire31.

In the following description, a signal transmitted from the first integrated circuit13to the stylus P will be referred to as a first uplink signal US1, and a signal transmitted from the second integrated circuit23to the stylus P will be referred to as a second uplink signal US2. It is noted that, when the first uplink signal US1and the second uplink signal US2do not need to be distinguished from each other, the first uplink signal US1and the second uplink signal US2may be collectively referred to as an uplink signal US. Further, a signal transmitted from the stylus P will be referred to as a downlink signal DS.

A region US1aillustrated inFIG.1is a range that the first uplink signal US1can reach. Further, a region US2aillustrated inFIG.1is a range that the second uplink signal US2can reach. As is clear from the description ofFIG.1, the region US1aand the region US2aoverlap with each other depending on the angle formed between the first housing10and the second housing20. The stylus P present within this overlapping region can receive both the first uplink signal US1and the second uplink signal US2. Therefore, it is necessary to prevent interference between the first uplink signal US1and the second uplink signal US2in the electronic device1.

Referring back toFIG.2, the host processor30is a central processing unit of the electronic device1that executes an operating system and various applications of the electronic device1by reading and executing programs stored in a memory, which is not illustrated. The host processor30also plays a role of accepting pen input by the stylus P or touch input by the finger F via the first integrated circuit13and the second integrated circuit23and supplying the pen input or touch input to the operating system or an application. Examples of the application that operate in response to receipt of pen input or touch input include a drawing application. This type of application generates and draws stroke data based on the pen input or touch input.

FIG.3is a timing diagram illustrating an overview of operations of the first integrated circuit13and the second integrated circuit23. As illustrated in this figure, the first integrated circuit13and the second integrated circuit23are configured to alternately and repeatedly perform a pen detection operation PD for detecting the stylus P and a touch detection operation TD for detecting the finger F at the same timing.

The overview of each of the pen detection operation PD and the touch detection operation TD will be described below. It is noted that, although the following description takes the first integrated circuit13as an example, the description similarly applies to the second integrated circuit23.

First, the pen detection operation PD will be described. As illustrated inFIG.3, a period in which the pen detection operation PD is performed includes an uplink signal US transmission/reception period P1and a downlink signal DS transmission/reception period P2. Of these, the downlink signal DS transmission/reception period P2is divided into a plurality of time slots TS1to TSn, enabling a plurality of styluses P to transmit the downlink signal DS by time division multiplexing. Although not illustrated, another multiplexing method such as frequency division multiplexing or orthogonal frequency division multiplexing may be used in addition to or instead of time division multiplexing. The following description continues, taking as an example a case where time division multiplexing and frequency division multiplexing are used.

The first integrated circuit13is configured to periodically transmit the first uplink signal US1that includes pairing information by using the uplink signal US transmission/reception period P1. The pairing information specifies a local pen ID (Identifier), a time slot, and a frequency to be allocated to a newly detected stylus P. When the stylus P that has received this first uplink signal US1has not been paired with any of the integrated circuits, the stylus P transmits the downlink signal DS that includes a pen ID stored in its memory, by using the time slot and frequency indicated by the first uplink signal US1. At the same time, the stylus P stores the pairing information included in the first uplink signal US1in its memory.

Here, each time slot included in the transmission/reception period P2is assigned a number in advance, and the first integrated circuit13is configured to specify a time slot by specifying the assigned number. The stylus P is configured to determine a temporal position of each time slot based on a timing at which the first uplink signal US1has been received and then transmit the downlink signal DS in the time slot allocated by the pairing information. The example illustrated inFIG.3is a case where time slots TS2, TS4, and TSn are allocated by the pairing information.

The first integrated circuit13that has received the downlink signal DS stores the received pen ID in its memory in association with the above-described pairing information. Pairing between the first integrated circuit13and the stylus P is completed through the processing up to this point. After that, the first integrated circuit13transmits the first uplink signal US1including the local pen ID and a command as necessary to instruct the paired stylus P what data the stylus P should transmit.

The stylus P is configured to transmit a position signal and a data signal as the downlink signal DS. The position signal is a burst signal. The data signal is a signal obtained by modulating a predetermined carrier signal by using the data indicated (requested) by the first uplink signal US1. The first integrated circuit13derives the position of the stylus P based on reception strength of the position signal at each of the sensor electrodes12xand12y, and obtains the data transmitted from the stylus P by receiving and demodulating the data signal. The first integrated circuit13then outputs the position data indicating the derived position and the data obtained from the stylus P to the host processor30.

Next, the touch detection operation TD will be described.FIG.4is a diagram illustrating a principle of the touch detection operation TD. Although only four sensor electrodes12xare illustrated in this figure to simplify illustration, more sensor electrodes12xare arranged in actual implementation. The following description continues, assuming that the number of sensor electrodes12xis K.

The first integrated circuit13when performing the touch detection operation TD supplies a finger touch detection signal FDS to each sensor electrode12x. As illustrated inFIG.4, the finger touch detection signal FDS includes K signals s1to sK. Each of the K signals s1to sKis made up of K pulses each represented by “1” or “−1,” for example. The nth pulses (n=1 to K) of the respective signals s1to sKconstitute a pulse group pn. The pluses constituting one pulse group Pnare individually input into the respective sensor electrodes12xin parallel.

While the number of sensor electrodes12xis assumed to be four (i.e., K=4) in the following description, the description similarly applies to a case where the number of sensor electrodes12xis three or less or five or more. When the number of sensor electrodes12xis four, each of the signals s1to sKis made up of four pulses each represented by “1” or “−1.” Specifically, as illustrated inFIG.4, the signal s1is made up of “1, 1, 1, 1,” the signal s2is made up of “1, 1, −1, −1,” the signal s3is made up of “1, −1, −1, 1,” and the signal s4is made up of “1 −1, 1, −1.”

The first integrated circuit13includes a shift register13aand a correlator13b. The shift register13ais a FIFO (First-In First-Out)-type storage unit and is configured to store the same number (i.e., K) of pieces of data as the number of sensor electrodes12x. When new data is stored in the shift register13a, the data that has been stored K times prior is deleted from the shift register13a. The first integrated circuit13selects one sensor electrode12yand sequentially inputs the pulse groups p1to p4to each sensor electrode12x. The first integrated circuit13repeats this operation for each sensor electrode12y. Accordingly, four levels L1to L4corresponding to the respective pulse groups p1to p4sequentially appear in the selected sensor electrode12y. The first integrated circuit13sequentially obtains the levels L1to L4appearing in the sensor electrode12yin this way, and each time the first integrated circuit13obtains the level, the first integrated circuit13stores the obtained level in the shift register13a.

The specific contents of the levels L1to L4will be described in detail, taking as an example a case where a sensor electrode12y1illustrated inFIG.4is selected. In the following description, capacitances formed between the sensor electrode12y1and four sensor electrodes12x1to12x4will be referred to as C11to C41, respectively.

First, the level L1corresponding to the pulse group p1and stored in the shift register13ais an inner product of a capacitance vector (C11, C21, C31, C41) and a vector (1, 1, 1, 1) indicating the pulse group p1. This inner product is calculated as C11+C21+C31+C41as also illustrated inFIG.4. Similarly, the level L2corresponding to the pulse group p2and stored in the shift register13ais an inner product of the capacitance vector (C11, C21, C31, C41) and a vector (1, 1, −1, −1) indicating the pulse group p1, which is calculated as C11+C21−C31−C41. The level L3corresponding to the pulse group p3and stored in the shift register13ais an inner product of the capacitance vector (C11, C21, C31, C41) and a vector (1, −1, −1, 1) indicating the pulse group p3, which is calculated as C11−C21−C31+C41. The level L4corresponding to the pulse group p4and stored in the shift register13ais an inner product of the capacitance vector (C11, C21, C31, C41) and a vector (1, −1, 1, −1) indicating the pulse group p4, which is calculated as C11−C21+C31−C41.

The first integrated circuit13uses the correlator13bto sequentially calculate correlation values T1to T4correlating with the levels L1to L4accumulated in the shift register13afor the respective four pulse groups p1to p4. As illustrated inFIG.4, the specific contents of the correlation values T1to T4calculated in this way are4C11,4C21,4C31, and4C41, respectively. That is, the correlation values T1to T4each reflect changes in capacitances formed at intersections of the sensor electrodes12x1to12x4and the sensor electrode12yi. Therefore, the first integrated circuit13can detect the position of the finger F by referring to the correlation values T1to T4calculated for each sensor electrode12y. Specifically, it suffices that the first integrated circuit13determines a region within the first panel surface11where changes in capacitances are equal to or greater than a predetermined value and detects the center position of the region as the position of the finger F, for example. The first integrated circuit13is configured to also output the position data indicating the position detected in this way to the host processor30.

FIGS.5A and5Bare diagrams each illustrating an example of specific waveforms of the signals s1to sKthat constitute the finger touch detection signal FDS. The signals s1to sKaccording to a first example illustrated inFIG.5Ainclude signals representing “1” by a relatively high voltage and “−1” by a relatively low voltage. Meanwhile, the signals s1to sKaccording to a second example illustrated inFIG.5Binclude signals obtained by Manchester-encoding the signals s1to sKaccording to the first example. Specifically, each signal representing a signal value consists of a first half portion, which represents “1” or “−1” depending on a high or low voltage, and a latter half portion, which represents the intermediate voltage. In the following description, a section in which the value of “1” or “−1” is reflected in the voltage may be occasionally referred to as a single pulse section PS, as illustrated inFIGS.5A and5B.

Next, a configuration of the sensor system3that relates to the characteristics of the present disclosure will be described in detail with reference toFIGS.6to8.

FIG.6is a timing diagram of signals transmitted and received by each of the first integrated circuit13, the second integrated circuit23, and the stylus P. Illustrated in this figure is a state in which the first integrated circuit13and the stylus P have already been paired.

As illustrated inFIG.6, the sensor system3according to the present embodiment controls the first integrated circuit13and the second integrated circuit23such that the first uplink signal US1, which is transmitted from the first integrated circuit13via the first sensor electrode groups12xand12y, and the second uplink signal US2, which is transmitted from the second integrated circuit23via the second sensor electrode groups22xand22y, are not transmitted at the same time. Specifically, the host processor30may control the first integrated circuit13and the second integrated circuit23such that the first uplink signal US1and the second uplink signal US2are not transmitted at the same time, or the first integrated circuit13and the second integrated circuit23may communicate with each other so as to control the first integrated circuit13and the second integrated circuit23such that the first uplink signal US1and the second uplink signal US2are not transmitted at the same time.

As a result of such processing, in the example illustrated inFIG.6, the first uplink signal US1is transmitted within a period of a time length T1from the beginning of the period in which the pen detection operation PD is performed, whereas the second uplink signal US2is transmitted after a time length T2(>T1), which is longer than the time length T1, has elapsed since the beginning of the pen detection operation PD. As a result, the first uplink signal US1and the second uplink signal US2are not transmitted at the same time. Accordingly, it is possible to prevent interference between the uplink signal US transmitted from the first panel surface11and the uplink signal US transmitted from the second panel surface21.

In addition, the first integrated circuit13further controls the paired stylus P such that the paired stylus P does not perform a receiving operation (denoted as “R” inFIG.6) except for a period in which the first uplink signal US1is being transmitted. Specifically, at the time of pairing, the first integrated circuit13notifies the stylus P of a time length INT illustrated inFIG.6. The time length INT represents an interval between transmissions of the uplink signal US. After receiving the uplink signal US, the stylus P operates so as to stop the receiving operation during the notified time length INT. Accordingly, it is possible to prevent the stylus P paired with the first integrated circuit13from receiving the uplink signal US transmitted from the second integrated circuit23.

Although this description similarly applies to the second integrated circuit23, it is preferable that, at the time of pairing, the second integrated circuit23further notify the stylus P of a time length T3(a time length from the end of transmission of the second uplink signal US2to the start of the touch detection operation TD) and a time length T4(a time length of a period in which the touch detection operation TD is performed) illustrated inFIG.6. In this way, based on the timing at which the second uplink signal US2has been received, the stylus P can determine the temporal position of each time slot for transmitting the downlink signal DS while excluding the period in which the touch detection operation TD is performed.

Further, the first integrated circuit13and the second integrated circuit23are configured such that, when one of the first integrated circuit13and the second integrated circuit23is paired with the stylus P, the pairing information regarding the pairing is shared with the other one of the first integrated circuit13and the second integrated circuit23. In sharing the pairing information, one of the first integrated circuit13and the second integrated circuit23may transmit the pairing information to the host processor30and the host processor30may transmit this pairing information to the other one of the first integrated circuit13and the second integrated circuit23, or one of the first integrated circuit13and the second integrated circuit23may directly transmit the pairing information to the other one of the first integrated circuit13and the second integrated circuit23. This eliminates the need for performing pairing again when the stylus P moves between the first panel surface11and the second panel surface21, thereby enabling continuous use of the stylus P across the first panel surface11and the second panel surface21.

Further, while one of the first integrated circuit13and the second integrated circuit23is performing the touch detection operation TD, the sensor system3according to the present embodiment restricts the other one of the first integrated circuit13and the second integrated circuit23from performing the touch detection operation TD. This point will be described in detail below with reference toFIG.7.

FIG.7is a diagram illustrating a state in which the user is sliding the finger F on the first panel surface11with a hand H resting on the second panel surface21. In response to the user performing this operation, capacitive coupling occurs not only between the sensor electrodes12xand12yand the hand H in a region A1(a region in contact with the finger F) within the first panel surface11illustrated inFIG.7, but also between the sensor electrodes22xand22yand the hand H in a region A2(a region in contact with the palm) within the second panel surface21illustrated inFIG.7. As a result, the finger touch detection signal FDS that is being transmitted from the second integrated circuit23is received by the first integrated circuit13through a path B illustrated inFIG.7. Such reception needs to be avoided because this causes malfunction of the first integrated circuit13and the host processor30.

Accordingly, while one of the first integrated circuit13and the second integrated circuit23is performing the touch detection operation TD, the sensor system3according to the present embodiment restricts the other one of the first integrated circuit13and the second integrated circuit23from performing the touch detection operation TD. The restriction may be performed such that, while the coordinates of the finger F are being supplied from one of the first integrated circuit13and the second integrated circuit23, the host processor30restricts the other one of the first integrated circuit13and the second integrated circuit23from performing the touch detection operation TD, or one of the first integrated circuit13and the second integrated circuit23that is detecting the finger F notifies the other circuit that the finger F is being detected. Accordingly, it is possible to prevent the finger touch detection signal FDS that is being transmitted from one of the first integrated circuit13and the second integrated circuit23from being received by the other one of the first integrated circuit13and the second integrated circuit23.

It is noted that the first integrated circuit13and the second integrated circuit23or the host processor30preferably detects the area of each region where the touch is detected (the regions A1and A2illustrated inFIG.7) and selects the integrated circuit to be restricted (prevented) from performing the touch detection operation TD based on the detected areas. In general, the area detected by the contact of a fingertip is smaller than the area detected by the contact of the palm and, thus, it is possible to select the integrated circuit in this way to prioritize touch input by the finger F.

Further, in restricting the touch detection operation TD, in one specific example, it suffices that the touch detection operation TD by the selected integrated circuit is completely stopped. Further, in another example, it suffices that, when the selected integrated circuit is the second integrated circuit23, for example, the second integrated circuit23is controlled so as to perform the touch detection operation TD without using part of the sensor electrodes22x(the sensor electrodes22xin a region C illustrated inFIG.7) close to the first sensor electrode groups12xand12y.

FIG.8is a diagram illustrating yet another example of the restriction of the touch detection operation TD. In this example, the second integrated circuit23does not perform the touch detection operation TD while the first integrated circuit13is performing the touch detection operation TD, and the first integrated circuit13does not perform the touch detection operation TD while the second integrated circuit23is performing the touch detection operation TD. To implement this operation, it is preferable that one of the first integrated circuit13and the second integrated circuit23notify the other one of the first integrated circuit13and the second integrated circuit23of the start timing and the end timing of the touch detection operation TD, either directly or via the host processor30.

As described above, with the sensor system3according to the present embodiment, the first uplink signal US1and the second uplink signal US2are not transmitted at the same time. Therefore, it is possible to prevent interference between the uplink signal US transmitted from the first panel surface11and the uplink signal US transmitted from the second panel surface21.

Further, with the sensor system3according to the present embodiment, the pairing information is shared between the first integrated circuit13and the second integrated circuit23. This enables continuous use of the stylus P across the first panel surface11and the second panel surface21.

Further, with the sensor system3according to the present embodiment, while one of the first integrated circuit13and the second integrated circuit23is performing the touch detection operation TD, the other one of the first integrated circuit13and the second integrated circuit23is restricted from performing the touch detection operation TD. Therefore, it is possible to prevent the finger touch detection signal FDS that is being transmitted from one of the first integrated circuit13and the second integrated circuit23from being received by the other one of the first integrated circuit13and the second integrated circuit23.

Moreover, with the sensor system3according to the present embodiment, the first integrated circuit13and the second integrated circuit23each perform the touch detection operation TD in synchronization with each other. Therefore, the host processor30can correctly process the sequence of the position data of the finger F supplied from each of the first integrated circuit13and the second integrated circuit23.

Next, a second embodiment of the present disclosure will be described. The present embodiment is different from the first embodiment in the solution to the problem described with reference toFIG.7and is similar to the first embodiment in other respects.

Therefore, the following description continues, focusing on the difference from the first embodiment.

FIGS.9A and9Bare diagrams each illustrating waveforms of the finger touch detection signal FDS according to the present embodiment.FIG.9Aillustrates the case where the finger touch detection signal FDS is made up of the signals with the waveforms illustrated inFIG.5A.FIG.9Billustrates the case where the finger touch detection signal FDS is made up of the signals with the waveforms illustrated inFIG.5B.

The first integrated circuit13and the second integrated circuit23are each configured to receive the finger touch detection signal FDS by detecting a change in the signal at the edge (leading edge) of each pulse section PS. Therefore, in the present embodiment, the finger touch detection signal FDS supplied from the first integrated circuit13to each sensor electrode12x(hereinafter referred to as a first finger touch detection signal FDS) and the finger touch detection signal FDS supplied from the second integrated circuit23to each sensor electrode22x(hereinafter referred to as a second finger touch detection signal FDS) are each configured such that the temporal positions of the edges of their respective pulse sections PS are different from each other between the first finger touch detection signal FDS and the second finger touch detection signal FDS.

In a typical example, it suffices that the first finger touch detection signal FDS and the second finger touch detection signal FDS are made up of pulse signals having different phases from each other. For example, as illustrated inFIGS.9A and9B, it suffices that the first finger touch detection signal FDS and the second finger touch detection signal FDS are configured such that their respective phases are different from each other by a time PS/2 that is one half of the above-described single pulse section PS. Accordingly, the temporal positions of the edges of the pulse sections PS (timings denoted by black triangles inFIG.9A and9B) can be different from each other between the first finger touch detection signal FDS and the second finger touch detection signal FDS.

In this way, the first finger touch detection signal FDS and the second finger touch detection signal FDS are configured such that the temporal positions of the edges of their respective pulse sections PS are different from each other between the first finger touch detection signal FDS and the second finger touch detection signal FDS. Accordingly, at a timing when one of the first integrated circuit13and the second integrated circuit23performs the operation of detecting a signal change, a signal corresponding to the other circuit always remains unchanged. Therefore, it is possible to prevent the finger touch detection signal FDS that is being transmitted from one of the first integrated circuit13and the second integrated circuit23from being received by the other one of the first integrated circuit13and the second integrated circuit23.

It is noted that, instead of the phases of the first finger touch detection signal FDS and the second finger touch detection signal FDS, their frequencies (i.e., the time length of the pulse section PS) may be different from each other. In this way, the temporal positions of the edges of the pulse sections PS can also be substantially, though not completely, (that is, at most of the timings) different from each other between the first finger touch detection signal FDS and the second finger touch detection signal FDS.

Further, in addition to each configuring the first finger touch detection signal FDS and the second finger touch detection signal FDS such that their respective rising and falling time lengths are different from each other between the first finger touch detection signal FDS and the second finger touch detection signal FDS, the first integrated circuit13and the second integrated circuit23may be each configured to receive only the finger touch detection signal FDS of a specific frequency by using a band-pass filter that passes only a signal of the specific frequency, for example. In this way, it is also possible to prevent the finger touch detection signal FDS that is being transmitted from one of the first integrated circuit13and the second integrated circuit23from being received by the other one of the first integrated circuit13and the second integrated circuit23.

Further, if an increase in bit lengths of the above-described signals s1to sKis acceptable, all of the signals s1to sKtransmitted from the first integrated circuit13and the signals s1to sKtransmitted from the second integrated circuit23may be made up of code strings orthogonal to each other. In this way, each of the first integrated circuit13and the second integrated circuit23can receive each signal in a distinguished manner by calculating correlation with the orthogonal code strings stored in advance. Accordingly, similarly to the description above, it is possible to prevent the finger touch detection signal FDS that is being transmitted from one of the first integrated circuit13and the second integrated circuit23from being received by the other one of the first integrated circuit13and the second integrated circuit23.

Although the preferred embodiments of the present disclosure have been described above, the present disclosure is by no means limited to the above-described embodiments. As a matter of course, the present disclosure can be implemented in various modes without departing from the scope of the present disclosure.

For example, the first integrated circuit13and the second integrated circuit23may transmit their respective uplink signals US with the same content at the same timing. In other words, the first integrated circuit13and the second integrated circuit23may be integrally operated. In this way, it is also possible to prevent interference between the uplink signal US transmitted from the first panel surface11and the uplink signal US transmitted from the second panel surface21. In this case as well, as to the touch detection operation TD, it is preferable to ensure that, in the way described above, the finger touch detection signal FDS that is being transmitted from one of the first integrated circuit13and the second integrated circuit23is not received by the other one of the first integrated circuit13and the second integrated circuit23.

It is noted that, when both the first panel surface11and the second panel surface21are configured by touch displays employing the in-cell system described above and the first integrated circuit13and the second integrated circuit23transmit their respective uplink signals US with the same content at the same timing as described above, it is preferable to synchronize vertical synchronization signals VSync indicating a screen rewriting timing. That is, with the touch displays employing the in-cell system, the sensor system3can perform the pen detection operation PD and the touch detection operation TD only during a blank period in which a pixel driving operation is not performed. Therefore, in order for the first panel surface11and the second panel surface21to transmit their respective uplink signals US at the same timing, the temporal positions of the blank periods need to match between the first panel surface11and the second panel surface21. By synchronizing the vertical synchronization signals VSync with each other as described above, the temporal positions of the blank periods can match.

Further, the first uplink signal US1and the second uplink signal US2may be made up of signals modulated by using code strings orthogonal to each other. In this way, the stylus P can receive the first uplink signal US1and the second uplink signal US2in a distinguished manner by calculating the correlation with the orthogonal code strings stored in advance. Therefore, similarly to the description above, it is possible to prevent interference between the uplink signal US transmitted from the first panel surface11and the uplink signal US transmitted from the second panel surface21. It is noted that, when, in this case, the stylus P receives both the first uplink signal US1and the second uplink signal US2, it is preferable that the stylus P select one of the first uplink signal US1and the second uplink signal US2and perform pairing with the integrated circuit that corresponds to the selected one. For example, it suffices that the stylus P selects one of the first uplink signal US1and the second uplink signal US2that exhibits a greater reception strength.

DESCRIPTION OF REFERENCE SYMBOLS

1: Electronic device2: Connecting portion3: Sensor system10: First housing11: First panel surface12x,12y: First sensor electrode group13: First integrated circuit13a: Shift register13b: Correlator14x,14y: First lead-out wire20: Second housing21: Second panel surface22x,22y: Second sensor electrode group23: Second integrated circuit24x,24y: Second lead-out wire30: Host processor31to33: Wire (Line/Trace)A1: A region in contact with a finger FA2: A region in contact with a palmDS: Downlink signalF: FingerFDS: Finger touch detection signalH: HandINT: A time length of an interval for transmitting an uplink signal USP: StylusP1: Uplink signal US transmission/reception periodP2: Downlink signal DS transmission/reception periodp1to p4: Pulse groupPD: Pen detection operationPS: Pulse sections1to sK: SignalT1: A time length of a period in which a first uplink signal US1is transmittedT1to T4: Correlation valueT2: A time length from the beginning of the pen detection operation PD to the start of transmission of a second uplink signal US2T3: A time length from the end of transmission of the second uplink signal US2to the start of a touch detection operation TDT4: A time length of a period in which the touch detection operation TD is performedTD: Touch detection operationTS1to TSn: Time slotUS: Uplink signalUS1: First uplink signalUS1a: A range that the first uplink signal US1can reachUS2: Second uplink signalUS2a: A range that the second uplink signal US2can reach