WO2015167418A1

WO2015167418A1 - Perform a self-capacitive scan of a stylus

Info

Publication number: WO2015167418A1
Application number: PCT/US2014/035612
Authority: WO
Inventors: Shan-Chih Chen; Kuan-Ting Wu; Ching-Yang Chang
Original assignee: Hewlett-Packard Development Company. L. P.
Priority date: 2014-04-28
Filing date: 2014-04-28
Publication date: 2015-11-05

Abstract

A stylus includes a controller. The controller performs a self-capacitive scan to determine whether a user is holding the electrically conductive shaft. The controller also places the stylus in one of a normal mode and a power saving mode which consumes less power than the normal mode based on a determination of the self-capacitive scan.

Description

PERFORM A SELF-CAPACfT!VE SCAN OF A STYLUS

BACKGROUND OOIj Styluses provide information to computing devices.

Styluses include capacitive active styluses to provide driving signals to computing devices and provide pressure to input members of the computing devices to convey information. The capacitive active styluses consume power to generate the driving signals.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] Non-limiting examples of the present disclosure are described in the following description, read with reference to the figures attached hereto and do not limit the scope of the ciaims. In the f igures, identical and similar structures, elements or parts thereof that appear in more than one figure are generally labeled with the same or similar references in the figures in which they appear. Dimensions of components, layers, substrates and features illustrated in the figures are chosen primarily for convenience and clarity of presentation and are not necessarily to scale. Referring to the attached figures:

[0003] FIG. 1 is a block diagram illustrating a stylus according to an example. [0004] FIG, 2 is a schematic view illustrating a styius according to an example.

QOOS] FIG. 3 is a graph illustrating driving signals generated by the styius of FIG. 2 according to an example,

[0006] FIG. 4 is a graph illustrating a self-capacitance scan signal of the styius of FIG. 2 according to an example.

[0007] FiG, 5 is a block diagram illustrating a computing system according to an example.

[0008] FiG. 8 is a schematic view illustrating the computing system of FIG. 5 according to an example.

£0009] FIG. 7 is a flowchart illustrating a method of operating a stylus with a computing device according to an example,

DETAILED DESCRIPTION

[0010] Capacitive active styluses provide driving signals to computing devices having capacitive sensing touc screens to convey information thereto, A capacitive active stylus also consumes power to generate driving signals at a constant frequency and voitage to be received by the computing device such as sense electrodes of capacitive sensing touch screens to form a capacitive coupled relationship. When an object such as a styius touches or comes within proximity of a touch screen, a change in capacitance may occur corresponding to a position of the styius within a touch- sensitive area of the touch screen. The continued generation of the driving signal by the stylus at a constant frequency and voltage consumes a lot of power over time. Accordingly, a cost of operating the stylus, a cost of battery replacement, and/or a frequency of battery replacement may be increased,

[0011] In examples, a stylus includes a styius tip, a main body, and a controller. The stylus tip contacts an input member of the computing device to convey information therewith. The mai body includes an electrically conductive shaft and a non-eiectricaily conductive member extending from the electrically conductive surface. The controller performs a seif-capacitive scan to determine whether a user is holding the electrically conductive shaft. The controller places the stylus in one of a normal mode and a power saving mode which consumes less power than the normal mode based on a determination of the seif-capacitfve scan. Thus, the generation of the driving signals at a Sower frequency in the power saving mode by the stylus may consume less power over time. Accordingly, the cost of operating the stylus, the cost of battery replacement, and/or the frequency of battery replacement may be decreased.

[0012] FIG. 1 is a block diagram illustrating a stylus according to an example. The stylus may be used with a computing device. A stylus 100 may be usable with a computing device. Referring to FIG. 1, in some examples, the stylus 100 includes a stylus tip 12, a main body 10, and a controller 11. The stylus tip 2 contacts an input member of the computing device to convey information therewith. For example, the input member may be a capacliive sensing touch screen. The main body 10 includes an electrically conductive shaft 13 and a non-electrica!!y conductive member 14 extending from the electrically conductive shaft 13. In some examples, the electrically conductive shaft 13 may be metallic such as aluminum, !n some examples, the non-eiectricaliy conductive member 14 may be plastic, hybrid material, and the like,

[00 33 Referring to FIG. 1 , in some examples, the controller 11 performs a self-capacitive scan to determine whether a user is holding the electrically conductive shaft 13. The controller 11 places the stylus in one of a normal mode and a power saving mode which consumes less power than the normai mode based on a determination of the self-ca acitive scan, The power saving mode, for example, ma correspond to an idle mode that consumes less power than the normal mode, in some examples, the controller 11 may be implemented in hardware, software including firmware, or combinations thereof. The firmware, for example, may be stored in memory and executed by a suitable instruction-execution system. If implemented in hardware, as in an alternative example, the controller 11 may be implemented with any or a combination of technologies which are well known in the art (for example, discrete-logic circuits, application-specific integrated circuits (ASICs), programmable-gats arrays (PGAs), field-programmable gate arrays (FPGAs)), and/or other Safer developed technologies. In other examples, the controller 1 1 may be implemented in a combination of software and data executed and stored under the control of a computing system.

[0014] FIG. 2 is a schematic view illustrating a stylus according to an exampie. FSG. 3 is a graph illustrating driving signals generated by the stylus of FIG. 2 according to an example. FIG. 4 is a graph illustrating a self- capacitance scan signal of the stylus of FIG. 2 according to an example, A stylus 200 may foe used with a computing device. Referring to FIGS. 2-4, in some examples, the stylus 200 may include the stylus tip 12, the main body 10, and the controller 11 as previously discussed with respect to the stylus 100 of FIG. 1. The stylus tip 2, for exampie, may Include a metal member 12a and a piastic member 12b covering an end portion of the metal member 12a. The plastic member 12D may reduce scratching of the input member.

[0015] The stylus 200 may aiso include a capacitance sensor 25, a battery compartment 26, a battery 27, and a pressure sensor 28 as illustrated in FIG. 2. The pressure sensor 28 may provide an output based on an amount of pressure applied between the stylus ti 12 and the input member. The controller 1 may include the capacitive sensor 25, for exampie, to provide an output based on an amount of capacitance of the electrically conductive shaft 13. The controller 11 may be configured to place the stylus 200 in one of the norma! mode and the power saving mode. For exampie, the controller 11 may place the stylus 200 in the normal mode based on the determination of the self- capacitive scan that the user is holding the electrically conductive shaft 13 and the output of the pressure sensor 28 corresponding to contact between the stylus tip 12 and the input member. In some examples, the controller 11 may aiso place the stylus 200 in a deep sleep mode from the power saving mode. In some exampie, the controller may control generation of a seif-capacitance scan signal The self -capacitive scan may include determining a change in an amplitude of the self-capacitance scan signal based on a capacitive coupling between the electrically conductive shaft 13 and the user. In some examples, when the user is not holding the electrically conductive shaft 13 (a) of the stylus 200, the amplitude of self-capacitance scan signal may correspond to a voitage of a battery 27 powering the stylus such as 1.5 volts as illustrated in FIG. 4. Additionally, when the user is holding the electrically conductive shaft 13 (b) of the stylus, the amplitude of the self-capacitance scan signal may be reduced, for example, to about 0.1 volts as illustrated in FIG. 4.

[0016] Referring to FIGS. 2 and 3, the controller 11 may place the stylus 200 in the power saving mode, for example, based on the determination of the self-capacitive scan that the user is holding the electrically conductive shaft 13. The controller 11 may increase the frequency of the drive signals 29 when placing the stylus 200 in the norma! mode from the power saving mode, in some examples, in the normal mode, the controlle 1 may increase the frequency of the drive signals 29 as illustrated in F!G. 3. In some examples, in the norma! mode, the driving signal 29 may have a frequency in a range from 10 kiiohertz (kHz) to 150 kHz and an amplitude in a range from 25 voits to 90 volts such as 75 voits. Additionally, the controller 11 may place the stylus 200 in the power saving mode based on the determination that the stylus 200 doesn't contact the input member 51 for an amount of time, and in the deep sleep mode based on the determination of the self-capacitive scan that the user is not holding the electrically conductive shaft 13,

[001 ] The controller 1 , for example, may increase the frequency of the drive signals 29 when placing the stylus 200 in the normal mode from the power saving mode- In some examples, in the power saving mode, the controller 11 ma decrease the frequency of the drive signals 29 as illustrated in FIG. 3. In some examples, in the power saving mode, the driving signal 20 may have a frequency in a range from 1 kHz to 15 kHz and an amplitude in a range from 25 volts to 90 volts such as 75 volts. The controller 11 may place the stylus 200 in a deep sleep mode from the power saving mode and turn off the drive signal 29. That is, the controller 11 may place the stylus 200 in the deep sleep mode which consumes less power than the power saving mode based on the determination of the self-capacitive scan that the user is not holding the electrically conductive shaft 13. [0018] Referring to FIGS. 2 and 3, in some examples, the pressure sensor 28 may detect contact between the stylus tip 12 and the input member of the computing device. In some examples, the pressure sensor 28 may detect vary amounts of pressure applied between the stylus tip 12 and input member. The controller 1 1 may also initiate the self-capacitive scan in response to a determination that the stylus tip 12 doesn't contact the input member, for example, based on the amount of time of non-contact there between.

[0019] Referring to FIGS. 3 and 4, in some examples, the non- eiectricaiiy conductive member 14 includes a plurality of non-electricaily conductive members. The non-electricaily conductive members 14 may contact a surface to place the stylus 200 on and electrically isolate the electrically conductive shaft 3 from the surface, for example, when not in use. That is. when the stylus 200 is not being used and placed on a surface such as an electricaily conductive surface, the non-electrical !y conductive members 14 may electrically isolate the electricaily conductive shaft 13 from the electrically conductive surface. Thus, the non-electricaily conductive members 14 may help prevent the surface from impacting the capacitance of the electrically conductive shaft 14 similar to that of a user.

[0020] FIG. 5 is a block diagram illustrating a computing system according to an example. FIG, 6 is a schematic view illustrating the computing system of FIG. 5 according to an example. Referring to FIGS. 5 and 6, in some examples, a computing system 500 includes an Input member 51 and a stylus 200, Th input member 51 such as a capacitive sensing touc screen, and the like, may receive input from the stylus 200. The stylus 200 includes a stylus tip 12, a main body 10, a pressure sensor 28, and a controller 1 1. The stylus tip 12, for example, contacts the input member 51 to provide the input thereto. The main body 10 includes an electrically conductive shaft 13 and a non-electricaily conductive member 14 extending from the electrically conductive shaft 13.

[00213 Referring to FiGS. 5 and 8, in some examples, the controller 11 performs a self-capacitive scan to determine whether a user is holding the electrically conductive shaft 13. For example, the se!f-capacitive scan may inciude determining a change in an amplitude of a self-capacitance scan signal based on a capacitive coupling between the electrically conductive shaft 13 and the user. The controller 11 also places the stylus 200 in one of a normal mode, an idle mode which consumes less power than the normal mode, and a deep sleep mode which consumes less power than the idle mode. For example, the controller 11 places the stylus 200 in the normal mode based on a determination of the self-capacitive scan that the user is holding the electrically conductive shaft 13. The controller 1 1 places the styius 200 in the idle mode based on the determination of non-contact between the stylus 200 and the input member 51 for an amount of time. The controller 11 places the stylus 200 in the deep sleep mode based on the determination of the self-capacitive scan that the user is not holding the electrically conductive shaft 13.

[0022] In some examples, the controller 11 may be implemented in hardware, software including firmware, or combinations thereof. The firmware, for example, may be stored in memory and executed b a suitable instruction- execution system. If implemented in hardware, as in an alternative example, the controller 11 may be implemented with any or a combination of technologies which are well known in the art (for example, discrete-logic circuits, application- specific integrated circuits (ASICs), programmable-gate arrays (PGAs), field- programmable gate arrays (FPGAs)), and/or other later developed technologies. In other examples, the controller 1 1 may be Implemented in a combination of software and data executed and stored under the controi of a computing system 500.

[0023] In some examples, the stylus 200 may have a pressure sensor 28. The pressure sensor 28 may detect contact between the stylus tip 12 and the input member 51. The pressure sensor 28 may also detect an amount of pressure between the styius tip 12 and the input member 51. in some examples, the controller 11 may determine an amount of time of the non- contact between the stylus tip 12 and the input member 51. The controiier 1 may also initiate the self-capacitive scan, for example, based on the amount of time of the non-contact between the stylus tip 12 and the input member 51, [0024] FIG, 7 is a flowchart illustrating a method of operating a stylus with a computing device according to an example, in some examples, the modules and/or assemblies implementing the method may be those described in relation to the styluses 100 and 200 of FIGS, 1 -6, Referring to FIG. 7, tn block S710, a self-capacitive scan is performed by a controller of a stylus to determine whether a user is holding an electricall conductive shaft of a main body of the stylus. For example, the self-capacitive scan may include determining a change in an amplitude of a self-capacitance scan signal based on a capacitive coupling between the electrically conductive shaft and the user, in block $712, the stylus is piaced in a deep sleep mode which consumes less power than in the normal mode in response to a determination of the self- capacitive scan that the user is not holding the electrically conductive shaft.

In b!ock S714, the stylus is piaced in the idle mode which consumes less power than in a normal mode in response to a determination of the self-capacitive scan that the user is holding the electrically conductive shaft. In addition, in block S718, whether a stylus tip of the stylus lacks contact with an input member of the computing device for a period of time is determined. For example, the controller may determine whether the stylus is piaced into the idle mode based on an amount of time of non-contact between the styius tip and the input member. In block S718, the self-capacitive scan is initiated to determine whether the user is holding the electrically conductive shaft in response to a determination to place the stylus into the idle mode to place the stylus in an idle mode based on a determination that the user is holding the electrically conductive shaft and to place the stylus in the deep sleep mode based on the determination that the user is not holding the electrically conductive shaft. In block S720₅ the styius is placed in the normal mode based on a determination that the stylus tip does not Sack contact with the input member of the computing device for a period of time.

[0026] It is to be understood that the flowchart of FIG, 7 illustrates architecture, functionality, and/or operation of examples of th present disclosure. If embodied in software, each block may represent a module, segment, or portion of code that includes one or more executable instructions to implement the specified logical function(s). If embodied in hardware, each block may represent a circuit or a number of interconnected circuits to

Implement the specified logical function(s). Although the flowchart of FIG. 7 illustrates a specific order of execution, the order of execution may differ from that which is depicted. For example, the order of execution of two or more blocks may be rearranged relative to the order illustrated. Also, two or more blocks illustrated in succession in FIG. 7 may be executed concurrently or with partial concurrence. All such variations are within the scope of the present disclosure.

[0027] The present disclosure has been described using non- limiting detailed descriptions of examples thereof and is not intended to limit the scope of the present disclosure, it should be understood that features and/or operations described with respect to one example may be used with other examples and that not all examples of the present disclosure have all of the features and/or operations illustrated in a particular figure or described with respect to one of the examples. Variations of examples described will occur to persons of the art. Furthermore, the terms "comprise/' "include," "have" and their conjugates, shall mean, when used in the present disdosure and/or claims, "including but not necessarily limited to,"

[0028] It is noted that some of the above described examples may include structure, acts or details of structures and acts that may not be essential to the present disclosure and are intended to be exemplary. Structure and acts described herein are replaceable by equivalents, which perform the same function, even if the structure or acts are different, as known in the art.

Therefore, the scope of the present disclosure is limited only by the elements and limitations as used in the claims.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A stylus usable with a computing device, the stylus comprising; a stylus tip to contact an input member of the computing device to convey information therewith;

a main body including an electrically conductive shaft and a non- eSectricalSy conductive member extending from the electrically conductive surface; and

a controller to perform a self-capacitive scan to determine whether a user is holding the electrically conductive shaft, and to place the styius in one of a normal mode and a power saving mode which consumes less power than the normal mode based on a determinatio of the self-capacitive scan,

2. The stylus of claim 1 , further comprising:

a pressure sensor to provide an output based on an amount of pressure applied between the stylus tip and the input member,

3. The stylus of claim 2, wherein the controller is configured to place th stylus in the norma! mode based on the determination of the self-capacitive scan that the user is holding the electrically conductive shaft and the output of the pressure sensor corresponding to contact between the stylus tip and the input member.

4. The styius of ciaim 2, wherein the controller is configured to place the stylus in the power saving mode based on the output of the pressure sensor correspondtng to a lack of contact between the stylus tip and the input member.

5. The styius of ciaim 1 , wherein the controller is configured to place the stylus in a deep sleep mode whic consumes less power than the power saving mode based on the determination of the self-capacitive scan that the user is not holding the electrically conductive shaft,

6. The styius of claim 1 , wherein the controller is configured to determine a period of time of the non-contact between the stylus tip and the input member, and to initiate the self-capacitive scan by the controller based on the period of time of th non-contact

7. The styius of claim 1 , wherein the seif-capadtive scan includes determining a change in an amplitude of a self-capacitance scan signal based on a capacstive coupling between the electrically conductive shaft and the user.

8. The styius of claim 1 , wherein the electricall conductive shaft is metallic.

9. The stylus of claim 1 , wherein the non-eiecirsca!!y conductive member comprises;

a plurality of non-electricaily conductive members to contact a surface to place the stylus on and electrically isolate the electrically conductive shaft from the surface.

10. The stylus of claim 1 , wherein the main body further comprises: a battery compartment to receive a battery to power drive signals having a frequency and a voltage from the stylus to be received by the input member.

11. The styius of claim 10, wherein the controller is configured to decrease the frequency of the drive signals when placing the styius in the power saving mode from the norma! mode, and to increase the frequency of the drive signals when placing the stylus in the normal mode from the power saving mode.

12. The stylus of claim 10, wherein the controller is configured to turn off the drive signals when placing the stylus in a deep sleep mode from the power saving mode, and to turn on the drive signals when placing the stylus in the power saving mode from the deep sleep mode,

13 A computi ng system , comprising :

an input member to receive input; and

a stylus including a stylus tip. a pressure sensor, a main body, and a controller,

the stylus tip to contact the input member to provide the input thereto;

a pressure sensor to provide an output based on an amount of pressure applied between the stylus tip and the input member;

the main body including an electrically conductive shaft and a non- electricaiiy conductive member extending from the electrically conductive shaft; and

the controller to perform a self-capacitive scan to determine whether a user is holding the electrically conductive shaft, and to place the stylus in one of a normal mode, an idle mode which consumes less power than the norma! mode, and a deep sleep mode which consumes less power than the idle mode based on at least one of the determination of the self-capacitive scan and the output of th pressure sensor.

14. A method of operating a stylus with a computing device, the method comprising:

performing a self-capacitive scan by a controller of a stylus to determine whether a user is holding an electrically conductive shaft of a main body of the stylus,

and if not:

placing the stylus in a deep sleep mode which consumes iess power than in an idle mode in response to a determination of the self-Gapacitive scan thai the user is not holding the electrically conductive shaft; and if so;

placing the stylus in the idle mode which consumes less power than in a normal mode in response to a determination of the seif-capacitive scan that the user is holding the electrically conductive shaft;

determining whether a stylus tip of the stylus lacks contact with an input member of the computing device for a period of time

and, if not;

placing the stylus in the normal mode based on a determination that the stylus tip does not lack contact with the input member of the computing device for a period of time.

15, The method of claim 14, further comprising;

initiating the seif-capacitive scan to determine whether the user is holding the electrically conductive shaft in response to a determination that the stylus tip does Sack contact with the input member of the computing device for the period of time to place the stylus in the idle mode based on a determination that the user is holding the electrically conductive shaft and to place the stylus in the deep sleep mode based on the determination that the user is not holding the electrically conductive shaft.