Touch sensor with capacitive nodes having a capacitance that is approximately the same

According to one embodiment, a touch sensor has a first edge and a second edge approximately perpendicular to the first edge. The touch sensor includes a first plurality of electrodes approximately parallel to the first edge, and a second plurality of electrodes. Each of the second plurality of electrodes has a spine that is approximately parallel to the second edge and a plurality of conductive elements that are approximately parallel to the first edge and in physical contact with the spine. At least one electrode of the second plurality of electrodes is adjacent to the second edge. The touch sensor further includes a plurality of nodes. Each node is formed by a capacitive coupling between an electrode of the first plurality of electrodes and an electrode of the second plurality of electrodes. The capacitance of each node is approximately the same.

TECHNICAL FIELD

This disclosure generally relates to touch sensors.

BACKGROUND

A touch sensor may detect the presence and location of a touch or the proximity of an object (such as a user's finger or a stylus) within a touch-sensitive area of the touch sensor overlaid on a display screen, for example. In a touch-sensitive display application, the touch sensor may enable a user to interact directly with what is displayed on the screen, rather than indirectly with a mouse or touch pad. A touch sensor may be attached to or provided as part of a desktop computer, laptop computer, tablet computer, personal digital assistant (PDA), smartphone, satellite navigation device, portable media player, portable game console, kiosk computer, point-of-sale device, or other suitable device. A control panel on a household or other appliance may include a touch sensor.

There are a number of different types of touch sensors, such as (for example) resistive touch screens, surface acoustic wave touch screens, and capacitive touch screens. Herein, reference to a touch sensor may encompass a touch screen, and vice versa, where appropriate. When an object touches or comes within proximity of the surface of the capacitive touch screen, a change in capacitance may occur within the touch screen at the location of the touch or proximity. A touch-sensor controller may process the change in capacitance to determine its position on the touch screen.

Touch sensors typically include an electrode pattern, such as one of the electrode patterns included in the touch sensors illustrated inFIGS. 1E-1H. Touch sensors with these typical electrode patterns, however, may be deficient.

DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1Aillustrates an example touch sensor10with an example touch-sensor controller12. Touch sensor10and touch-sensor controller12may detect the presence and location of a touch or the proximity of an object within a touch-sensitive area of touch sensor10. Herein, reference to a touch sensor may encompass both the touch sensor and its touch-sensor controller, where appropriate. Similarly, reference to a touch-sensor controller may encompass both the touch-sensor controller and its touch sensor, where appropriate. Touch sensor10may include one or more touch-sensitive areas, where appropriate. Touch sensor10may include an array of drive and sense electrodes (or an array of electrodes of a single type) disposed on one or more substrates, which may be made of a dielectric material. Herein, reference to a touch sensor may encompass both the electrodes of the touch sensor and the substrate(s) that they are disposed on, where appropriate. Alternatively, where appropriate, reference to a touch sensor may encompass the electrodes of the touch sensor, but not the substrate(s) that they are disposed on.

An electrode (whether a drive electrode or a sense electrode) may be an area of conductive material forming a shape, such as for example a disc, square, rectangle, thin line, other suitable shape, or suitable combination of these. One or more cuts in one or more layers of conductive material may (at least in part) create the shape of an electrode, and the area of the shape may (at least in part) be bounded by those cuts. In particular embodiments, the conductive material of an electrode may occupy approximately 100% of the area of its shape. As an example and not by way of limitation, an electrode may be made of indium tin oxide (ITO) and the ITO of the electrode may occupy approximately 100% of the area of its shape (sometimes referred to as 100% fill), where appropriate. In particular embodiments, the conductive material of an electrode may occupy substantially less than 100% of the area of its shape. As an example and not by way of limitation, an electrode may be made of fine lines of metal or other conductive material (FLM), such as for example copper, silver, or a copper- or silver-based material, and the fine lines of conductive material may occupy approximately 5% of the area of its shape in a hatched, mesh, or other suitable pattern. Herein, reference to FLM encompasses such material, where appropriate. Although this disclosure describes or illustrates particular electrodes made of particular conductive material forming particular shapes with particular fills having particular patterns, this disclosure contemplates any suitable electrodes made of any suitable conductive material forming any suitable shapes with any suitable fill percentages having any suitable patterns.

Where appropriate, the shapes of the electrodes (or other elements) of a touch sensor may constitute in whole or in part one or more macro-features of the touch sensor. One or more characteristics of the implementation of those shapes (such as, for example, the conductive materials, fills, or patterns within the shapes) may constitute in whole or in part one or more micro-features of the touch sensor. One or more macro-features of a touch sensor may determine one or more characteristics of its functionality, and one or more micro-features of the touch sensor may determine one or more optical features of the touch sensor, such as transmittance, refraction, or reflection.

A mechanical stack may contain the substrate (or multiple substrates) and the conductive material forming the drive or sense electrodes of touch sensor10. As an example and not by way of limitation, the mechanical stack may include a first layer of optically clear adhesive (OCA) beneath a cover panel. The cover panel may be clear and made of a resilient material suitable for repeated touching, such as for example glass, polycarbonate, or poly(methyl methacrylate) (PMMA). This disclosure contemplates any suitable cover panel made of any suitable material. The first layer of OCA may be disposed between the cover panel and the substrate with the conductive material forming the drive or sense electrodes. The mechanical stack may also include a second layer of OCA and a dielectric layer (which may be made of PET or another suitable material, similar to the substrate with the conductive material forming the drive or sense electrodes). As an alternative, where appropriate, a thin coating of a dielectric material may be applied instead of the second layer of OCA and the dielectric layer. The second layer of OCA may be disposed between the substrate with the conductive material making up the drive or sense electrodes and the dielectric layer, and the dielectric layer may be disposed between the second layer of OCA and an air gap to a display of a device including touch sensor10and touch-sensor controller12. As an example only and not by way of limitation, the cover panel may have a thickness of approximately 1 mm; the first layer of OCA may have a thickness of approximately 0.05 mm; the substrate with the conductive material forming the drive or sense electrodes may have a thickness of approximately 0.05 mm); the second layer of OCA may have a thickness of approximately 0.05 mm; and the dielectric layer may have a thickness of approximately 0.05 mm. Although this disclosure describes a particular mechanical stack with a particular number of particular layers made of particular materials and having particular thicknesses, this disclosure contemplates any suitable mechanical stack with any suitable number of any suitable layers made of any suitable materials and having any suitable thicknesses. As an example and not by way of limitation, in particular embodiments, a layer of adhesive or dielectric may replace the dielectric layer, second layer of OCA, and air gap described above, with there being no air gap to the display.

One or more portions of the substrate of touch sensor10may be made of polyethylene terephthalate (PET) or another suitable material. This disclosure contemplates any suitable substrate with any suitable portions made of any suitable material. In particular embodiments, the drive or sense electrodes in touch sensor10may be made of ITO in whole or in part. In particular embodiments, the drive or sense electrodes in touch sensor10may be made of fine lines of metal or other conductive material. As an example and not by way of limitation, one or more portions of the conductive material may be copper or copper-based and have a thickness of approximately 5 μm or less and a width of approximately 10 μm or less. As another example, one or more portions of the conductive material may be silver or silver-based and similarly have a thickness of approximately 5 μm or less and a width of approximately 10 μm or less. This disclosure contemplates any suitable electrodes made of any suitable material.

Touch sensor10may implement a capacitive form of touch sensing. In a mutual-capacitance implementation, touch sensor10may include an array of drive and sense electrodes forming an array of capacitive nodes. A drive electrode and a sense electrode may form a capacitive node. The drive and sense electrodes forming the capacitive node may come near each other, but not make electrical contact with each other. Instead, the drive and sense electrodes may be capacitively coupled to each other across a space between them. A pulsed or alternating voltage applied to the drive electrode (by touch-sensor controller12) may induce a charge on the sense electrode, and the amount of charge induced may be susceptible to external influence (such as a touch or the proximity of an object). When an object touches or comes within proximity of the capacitive node, a change in capacitance may occur at the capacitive node and touch-sensor controller12may measure the change in capacitance. By measuring changes in capacitance throughout the array, touch-sensor controller12may determine the position of the touch or proximity within the touch-sensitive area(s) of touch sensor10.

In a self-capacitance implementation, touch sensor10may include an array of electrodes of a single type that may each form a capacitive node. When an object touches or comes within proximity of the capacitive node, a change in self-capacitance may occur at the capacitive node and touch-sensor controller12may measure the change in capacitance, for example, as a change in the amount of charge needed to raise the voltage at the capacitive node by a pre-determined amount. As with a mutual-capacitance implementation, by measuring changes in capacitance throughout the array, touch-sensor controller12may determine the position of the touch or proximity within the touch-sensitive area(s) of touch sensor10. This disclosure contemplates any suitable form of capacitive touch sensing, where appropriate.

In particular embodiments, one or more drive electrodes may together form a drive line running horizontally or vertically or in any suitable orientation. Similarly, one or more sense electrodes may together form a sense line running horizontally or vertically or in any suitable orientation. In particular embodiments, drive lines may run substantially perpendicular to sense lines. Herein, reference to a drive line may encompass one or more drive electrodes making up the drive line, and vice versa, where appropriate. Similarly, reference to a sense line may encompass one or more sense electrodes making up the sense line, and vice versa, where appropriate.

Touch sensor10may have drive and sense electrodes disposed in a pattern on one side of a single substrate. In such a configuration, a pair of drive and sense electrodes capacitively coupled to each other across a space between them may form a capacitive node. For a self-capacitance implementation, electrodes of only a single type may be disposed in a pattern on a single substrate. In addition or as an alternative to having drive and sense electrodes disposed in a pattern on one side of a single substrate, touch sensor10may have drive electrodes disposed in a pattern on one side of a substrate and sense electrodes disposed in a pattern on another side of the substrate. Moreover, touch sensor10may have drive electrodes disposed in a pattern on one side of one substrate and sense electrodes disposed in a pattern on one side of another substrate. In such configurations, an intersection of a drive electrode and a sense electrode may form a capacitive node. Such an intersection may be a location where the drive electrode and the sense electrode “cross” or come nearest each other in their respective planes. The drive and sense electrodes do not make electrical contact with each other—instead they are capacitively coupled to each other across a dielectric at the intersection. Although this disclosure describes particular configurations of particular electrodes forming particular nodes, this disclosure contemplates any suitable configuration of any suitable electrodes forming any suitable nodes. Moreover, this disclosure contemplates any suitable electrodes disposed on any suitable number of any suitable substrates in any suitable patterns.

As described above, a change in capacitance at a capacitive node of touch sensor10.may indicate a touch or proximity input at the position of the capacitive node. Touch-sensor controller12may detect and process the change in capacitance to determine the presence and location of the touch or proximity input. Touch-sensor controller12may then communicate information about the touch or proximity input to one or more other components (such one or more central processing units (CPUs)) of a device that includes touch sensor10and touch-sensor controller12, which may respond to the touch or proximity input by initiating a function of the device (or an application running on the device). Although this disclosure describes a particular touch-sensor controller having particular functionality with respect to a particular device and a particular touch sensor, this disclosure contemplates any suitable touch-sensor controller having any suitable functionality with respect to any suitable device and any suitable touch sensor.

Touch-sensor controller12may be one or more integrated circuits (ICs), such as for example general-purpose microprocessors, microcontrollers, programmable logic devices or arrays, application-specific ICs (ASICs). In particular embodiments, touch-sensor controller12comprises analog circuitry, digital logic, and digital non-volatile memory. In particular embodiments, touch-sensor controller12is disposed on a flexible printed circuit (FPC) bonded to the substrate of touch sensor10, as described below. The FPC may be active or passive, where appropriate. In particular embodiments, multiple touch-sensor controllers12are disposed on the FPC. Touch-sensor controller12may include a processor unit, a drive unit, a sense unit, and a storage unit. The drive unit may supply drive signals to the drive electrodes of touch sensor10. The sense unit may sense charge at the capacitive nodes of touch sensor10and provide measurement signals to the processor unit representing capacitances at the capacitive nodes. The processor unit may control the supply of drive signals to the drive electrodes by the drive unit and process measurement signals from the sense unit to detect and process the presence and location of a touch or proximity input within the touch-sensitive area(s) of touch sensor10. The processor unit may also track changes in the position of a touch or proximity input within the touch-sensitive area(s) of touch sensor10. The storage unit may store programming for execution by the processor unit, including programming for controlling the drive unit to supply drive signals to the drive electrodes, programming for processing measurement signals from the sense unit, and other suitable programming, where appropriate. Although this disclosure describes a particular touch-sensor controller having a particular implementation with particular components, this disclosure contemplates any suitable touch-sensor controller having any suitable implementation with any suitable components.

Tracks14of conductive material disposed on the substrate of touch sensor10may couple the drive or sense electrodes of touch sensor10to connection pads16, also disposed on the substrate of touch sensor10. As described below, connection pads16facilitate coupling of tracks14to touch-sensor controller12. Tracks14may extend into or around (e.g. at the edges of) the touch-sensitive area(s) of touch sensor10. Particular tracks14may provide drive connections for coupling touch-sensor controller12to drive electrodes of touch sensor10, through which the drive unit of touch-sensor controller12may supply drive signals to the drive electrodes. Other tracks14may provide sense connections for coupling touch-sensor controller12to sense electrodes of touch sensor10, through which the sense unit of touch-sensor controller12may sense charge at the capacitive nodes of touch sensor10. Tracks14may be made of fine lines of metal or other conductive material. As an example and not by way of limitation, the conductive material of tracks14may be copper or copper-based and have a width of approximately 100 μm or less. As another example, the conductive material of tracks14may be silver or silver-based and have a width of approximately 100 μm or less. In particular embodiments, tracks14may be made of ITO in whole or in part in addition or as an alternative to fine lines of metal or other conductive material. Although this disclosure describes particular tracks made of particular materials with particular widths, this disclosure contemplates any suitable tracks made of any suitable materials with any suitable widths. In addition to tracks14, touch sensor10may include one or more ground lines terminating at a ground connector (which may be a connection pad16) at an edge of the substrate of touch sensor10(similar to tracks14).

Connection pads16may be located along one or more edges of the substrate, outside the touch-sensitive area(s) of touch sensor10. As described above, touch-sensor controller12may be on an FPC. Connection pads16may be made of the same material as tracks14and may be bonded to the FPC using an anisotropic conductive film (ACF). Connection18may include conductive lines on the FPC coupling touch-sensor controller12to connection pads16, in turn coupling touch-sensor controller12to tracks14and to the drive or sense electrodes of touch sensor10. In another embodiment, connection pads16may be connected to an electro-mechanical connector (such as a zero insertion force wire-to-board connector); in this embodiment, connection18may not need to include an FPC. This disclosure contemplates any suitable connection18between touch-sensor controller12and touch sensor10.

FIG. 1Billustrates a system100with a single-layer configuration of electrodes that implement self-capacitive coupling. According to the illustrated embodiment, field lines112extend from an electrode104(e.g. a drive electrode) operated by a circuit116, the fields penetrating through panel108. A portion of the emitted field lines112escapes into free space or other parts of the panel as shown, and capacitively couples with a finger (not shown) or other object when present. The circuit116observes a change in self-capacitance of the capacitive node formed by electrode104due to the presence of a finger (or other object) near field lines112, such as by observing that a greater charge is needed to change the voltage of the capacitive node.

FIG. 1Cillustrates a system200with a single-layer configuration of electrodes that implement mutual capacitive coupling. According to the illustrated embodiment, a finger224causes field lines216normally coupling from drive electrode204to sense electrode208to be absorbed by finger224, as shown at220. The result of this action is a very detectable change in capacitance of the capacitive node formed by drive electrode204and sense electrode208. In particular embodiments, the change in capacitance is related to a variety of factors such as fingerprint area, electrode area, panel212thickness and dielectric constant, human body size and location, skin thickness and conductivity, and other factors. In particular embodiments, the change in capacitance is sensed by receiver232.

FIG. 1Dillustrates a system300with a two-layer configuration of electrodes that implement mutual capacitive coupling. According to the illustrated embodiment, a finger324causes field lines316normally coupling from drive electrode304to sense electrode308across substrate310to be absorbed by finger324, as shown at320. The result of this action is a very detectable change in capacitance of the capacitive node formed by drive electrode304and sense electrode308. In particular embodiments, the change in capacitance is related to a variety of factors such as fingerprint area, electrode area, panel312thickness and dielectric constant, human body size and location, skin thickness and conductivity, and other factors. In particular embodiments, the change in capacitance is sensed by receiver332.

FIG. 1Eillustrates an example touch sensor400having a two-layer configuration of electrodes that implement mutual capacitance coupling. According to the illustrated embodiment, touch sensor400includes edges, drive electrodes, and sense electrodes.

Edges (which are illustrated inFIG. 1Eas edge404a, edge404b, edge404c, and edge404d) comprise a barrier between the touch-sensitive area of touch sensor400and a touch-insensitive area of touch sensor. In particular embodiments, when a user touches (or comes in close proximity to) touch sensor400within the edges, the touch (or close proximity) is sensed by touch sensor400.

Drive electrodes (one of which is illustrated inFIG. 1Eas drive electrode408) and sense electrodes (one of which is illustrated inFIG. 1Eas sense electrode412) are each an area of conductive material forming a shape, such as for example a disc, square, rectangle, other suitable shape, or suitable combination of these. In the illustrated embodiments, drive electrodes are disposed in a pattern on one side of a substrate and sense electrodes are disposed in a pattern on another side of the substrate. In such a configuration, an intersection of a drive electrode and a sense electrode may form a capacitive node (one of which is illustrated as capacitive node416). Such an intersection may be a location where the drive electrode and the sense electrode “cross” or come nearest each other in their respective planes. The drive and sense electrodes do not make electrical contact with each other—instead they are capacitively coupled to each other across the substrate at the intersection.

According to the illustrated embodiment, each sense electrode includes a spine (one of which is illustrated inFIG. 1Eas spine420) and one or more crossbars (one of which is illustrated inFIG. 1Eas crossbar424). Each crossbar includes two conductive elements (examples of which are illustrated inFIG. 1Eas conductive elements428aand428b) extending from either side of a spine. In one embodiment, the conductive elements overlap for about 50% of the distance between the spines. Thus, each conductive element extends about 75% of the distance between spines. In particular embodiments, the conductive elements may allow touch sensor400to sense a user when the user comes in contact (or comes in close proximity) to an area of touch sensor400that is in-between the spines of sense electrodes (such as in-between spine420of sense electrode412and the spine of the next adjacent sense electrode). In particular, when a user comes in contact (or comes in close proximity) to an area of touch sensor400that is in-between the spines of sense electrodes, a reasonable interpolated signal may be generated based on the user coming in contact (or coming in close proximity) to each of the conductive elements of the adjacent sense electrodes (as opposed to the spines themselves).

As illustrated, touch sensor400includes a example pattern for the drive electrodes and sense electrodes. According to the illustrated embodiments, the drive electrodes (such as drive electrode408) are parallel to edge404aand edge404d. In particular embodiments, the drive electrodes may be approximately parallel to edge404aand edge404d. For example, the drive electrodes may be approximately parallel to edge404aand edge404ddue to one or more deviations in the shape of edge404a, edge404d, and/or the drive electrodes. Furthermore, each adjacent drive electrode may be separated from the next drive electrode by a gap (one of which is illustrated inFIG. 1Eas drive electrode gap432).

In the illustrated embodiment, the spines of the sense electrodes (such as spine420of sense electrode412) are parallel to edge404band edge404c. In particular embodiments, the spines may be approximately parallel to edge404band edge404c. For example, the spines may be approximately parallel to edge404band edge404cdue to one or more deviations in the shape of edge404b, edge404c, and/or the spine. Furthermore, each spine may be separated from the spine of the next adjacent sense electrode by a gap (one of which is illustrated inFIG. 1Eas sense electrode spine gap436). In particular embodiments, each gap between adjacent spines is identical. For example, each gap may be 6 millimeters (mm). As another example, each gap may be 12 mm. As a further example each gap may be 6 mm-12 mm. As a further example, each gap may be less than 6 mm or greater than 12 mm. Additionally, each spine may have a width (one of which is illustrated inFIG. 1Eas sense electrode spine width440). In particular embodiments, the width of each spine is identical. For example, the width of each spine may be 0.5 mm. As another example, the width of each spine may be 1.5 mm. As a further example, the width of each spine may be 0.5 mm-1.5 mm. As a further example, the width of each spine may be less than 0.5 mm or greater than 1.5 mm.

In the illustrated embodiment, the conductive elements of the crossbars of the sense electrodes (such as conductive element428bof crossbar424of sense electrode412) are parallel to edge404aand edge404d. In particular embodiments, the conductive elements may be approximately parallel to edge404aand edge404d. For example, the conductive elements may be approximately parallel to edge404aand edge404ddue to one or more deviations in the shape of edge404a,404d, and/or the conductive elements. Furthermore, each conductive element may be separated from the next adjacent conductive element by a gap (one of which is illustrated inFIG. 1Eas conductive element gap444). In particular embodiments, each gap between adjacent conductive elements is identical. For example, each gap may be equal to the pitch of the drive electrodes. In particular, if the pitch of the drive electrodes is 5 mm, each gap between adjacent conductive elements may be 5 mm. As another example, each gap may be approximately equal to the pitch of the drive electrodes. In particular, if the pitch of the drive electrodes is 5 mm, each gap between adjacent conductive elements may be 4.5 mm-5.5 mm. In particular embodiments, if the drive electrodes are interdigitized (as is illustrated inFIG. 1F), each gap may be equal to twice the pitch of the interdigitized drive electrodes. For example, if the pitch of the interdigitized drive electrodes is 2.5 mm, each gap between adjacent conductive elements may be 5 mm. In particular embodiments, if the drive electrodes are interdigitized (as is illustrated inFIG. 1F), each gap may be approximately equal to twice the pitch of the interdigitized drive electrodes. For example, if the pitch of the interdigitized drive electrodes is 5 mm, each gap between adjacent conductive elements may be 4.5 mm-5.5 mm. Additionally, each conductive element may have a width (one of which is illustrated inFIG. 1Eas conductive element width448). In particular embodiments, the width of each conductive element is identical. For example, each width may be 0.3 mm. As another example, each width may be 1 mm. As a further example, each width may be 0.3 mm-1 mm. As a further example, each width may be less than 0.3 mm or greater than 1 mm.

As is discussed above, an intersection of a drive electrode and a sense electrode may form a capacitive node (one of which is illustrated inFIG. 1Eas capacitive node416). Each of these capacitive nodes may have a natural capacitance (Cx). According to the illustrated embodiment, the capacitance of each capacitive node in touch sensor400may not be the same. For example, the capacitive nodes that are located in the middle of touch sensor400may have the same capacitance, but the capacitive nodes along one or more of the edges of touch sensor400(such as the capacitive nodes that are closest to edge404band/or edge404c) may not have a capacitance that is the same as that of the other capacitive nodes (such as the capacitive nodes located in the middle of touch sensor400). In particular, each of the capacitive nodes that are formed by sense electrode412(which is the sense electrode that is adjacent to edge404b) may have a capacitance that is lower than the capacitance of the capacitive nodes that are formed by sense electrodes that are farther away from edge404b. In particular embodiments, such a lower capacitance also applies to the capacitive nodes that are formed by the sense electrode that is adjacent to the edge opposite of edge404b(which is illustrated as edge404c). The capacitive nodes that are closest to the edges (such as the capacitive nodes that are formed by the sense electrodes adjacent to edges404band404cand the capacitive nodes that are formed by drive electrodes adjacent to edges404aand404d) may be referred to as “edge capacitive nodes.”

In particular embodiments, the edge capacitive nodes (one of which is illustrated inFIG. 1Eas capacitive node416) may have a lower capacitance because the electrode pattern is cut off by the edges of touch sensor400. As an example, the conductive element that is closest to an edge (such as conductive element428bof crossbar424of sense electrode412, which is adjacent to edge404b) may be shorter than the other conductive elements (such as conductive element428a, or the conductive elements of the crossbars of the sense electrodes that are farther away from edge404bthan sense electrode412). For example, conductive element428amay be ⅓ the length of the other conductive elements. Because the conductive element that is closest to the edge is shorter than other conductive elements, the edge capacitive node (such as capacitive node416) may have less capacitance than other capacitive nodes of touch sensor400.

In particular embodiments, since some of the capacitive nodes of touch sensor400may have a different capacitance than other capacitive nodes of touch sensor400, the performance of touch sensor400may be deficient. For example, the sensitivity of touch sensor400may be different at the edge capacitive nodes than at any of the other capacitive nodes. As such, the accuracy of touch sensor400may be decreased and/or touch sensor400may be non-linear near the edges. In particular embodiments, touch sensor400may require one or more different gain settings, which may be detrimental to touch sensor400. As such, because the capacitance of the edge capacitive nodes is different from that of the other capacitive nodes, touch sensor400may be deficient.

In addition, the difference in capacitance between the edge capacitive nodes and other capacitive nodes is not limited to the electrode pattern illustrated inFIG. 1E. In particular, a difference in capacitance between edge capacitive nodes and other capacitive nodes may be found in various electrode patterns in both single-layer configurations and two-layer configurations of touch sensors. For example,FIGS. 1F-1H, described below, provide further examples electrode patterns that result in a difference between the capacitance of edge capacitive nodes and other capacitive nodes.

FIG. 1Fillustrates another example touch sensor500having a two-layer configuration of electrodes that implement mutual capacitance coupling. In particular embodiments, touch sensor500may be an alternative embodiment of touch sensor400ofFIG. 1E.

According to the illustrated embodiment, touch sensor500ofFIG. 1Fincludes the edges, drive electrodes, and sense electrodes described in detail inFIG. 1E. Furthermore, as is illustrated, the drive electrodes of touch sensor500ofFIG. 1F(one of which is illustrated as drive electrode408) further include interdigitized drive sections (one of which is illustrated as interdigitized drive section410). As is illustrated, each of the interdigitized drive sections (or otherwise referred to as “interpolated drive sections”) are in-between adjacent drive electrodes. In particular embodiments, the interdigitized drive sections may allow touch sensor500to sense a user when the user comes in contact (or comes in close proximity) to an area of touch sensor500that is in-between the drive electrodes (such as in-between drive electrode408and the next adjacent drive electrode). In particular, when a user comes in contact with (or comes in close proximity to) an area of touch sensor500that is in-between the drive electrodes, a reasonable interpolated signal may be generated based on the user coming in contact with (or coming in close proximity to) each of the interdigitized drive sections of the adjacent drive electrodes (as opposed to the drive electrodes themselves).

Similar toFIG. 1E, touch sensor500ofFIG. 1Falso include capacitive nodes that have a capacitance that is different from that of other capacitive nodes. As an example, the capacitance of the capacitive nodes formed by the sense electrodes that are adjacent to edges404band404cmay have a capacitance that is less than the capacitance of capacitive nodes formed by the other sense electrodes. In particular embodiments, this capacitance difference may be the result of the conductive elements of the sense electrodes that are adjacent to edges404band404c(such as conductive element428bof crossbar424of sense electrode412, which is adjacent to edge404b) being shorter than the other conductive elements (such as conductive element428a, or the conductive elements of the crossbars of the sense electrodes that are farther away from edge404bthan sense electrode412).

As another example, the capacitive nodes that are closest to edges404aand404dmay also have a capacitance that is less than that of capacitive nodes that are located farther away from edges404aand404d. In particular embodiments, this difference in capacitance may be the result of the interdigitized drive sections of the drive electrodes of touch sensor500. For example, according to the illustrated embodiment, each drive electrode includes interdigitized drive sections. However, the drive electrodes that are adjacent to edges404aand404d(such as drive electrode408, which is adjacent to edge404a) do not have any interdigitized drive sections that face edges404aand404d. For example, there is no interdigitized drive sections in-between drive electrode408and edge404a. In certain embodiments, this lack of interdigitized drive sections is the result of the edges404aand404dcutting off the electrode pattern. Furthermore, this lack of interdigitized drive sections facing the edges404aand404dmay result in a lower capacitance at the capacitive nodes that are closest to these edges (e.g., the edge capacitive nodes).

As a further example, the capacitive nodes that are closest to each of the corners of touch sensor500(for example, capacitive node416is the capacitive node that is closest to the corner created by edge404aand edge404b) may also have less capacitance than other capacitive nodes. In particular embodiments, the lower capacitance at these capacitive nodes may be the result of both the shorter conductive elements and the lack of an interdigitized drive section facing the edges. Accordingly, similar to touch sensor400ofFIG. 1E, touch sensor500ofFIG. 1Fmay also be deficient.

FIGS. 1G-1Hillustrate example touch sensors600and700having a two-layer configuration of electrodes that implement mutual capacitance coupling. In particular embodiments, touch sensors600and700may be alternative embodiments of touch sensor400ofFIG. 1E.

According to the illustrated embodiment, touch sensor600ofFIG. 1Gand touch sensor700ofFIG. 1Hincludes the edges, drive electrodes, and sense electrodes described in detail inFIG. 1E. The sense electrodes of touch sensor600ofFIG. 1Gand touch sensor700ofFIG. 1H, however, include a different pattern than that of touch sensor400ofFIG. 1E. In particular, each sense electrode (one of which is illustrated inFIGS. 1G and 1Has sense electrode412) includes multiple spines (examples of which are illustrated inFIGS. 1G and 1Has spines418and420). Additionally, although sense electrode412only includes two spines (such as spines418and420), each of the sense electrodes that are not adjacent to edges404band404cinclude three spines. Furthermore, in addition to each sense electrode having multiple spines, the spines of each sense electrode are coupled to each other by spinal elements (one of which is illustrated inFIGS. 1G and 1Has spinal element422). The sense electrode pattern ofFIGS. 1G and 1Hmay be referred to as a “trident” pattern.

Not only are the sense electrodes of touch sensor600ofFIG. 1Gand touch sensor700ofFIG. 1Harranged in a trident pattern, but touch sensors600ofFIG. 1Gand touch sensor700ofFIG. 1Hdo not include any crossbars. Additionally, similar toFIG. 1E, touch sensor700ofFIG. 1H(but not touch sensor600ofFIG. 1G) also includes interdigitized drive sections (one of which is illustrated as interdigitized drive section410).

Similar toFIGS. 1E and 1F, touch sensor600ofFIG. 1Gand touch sensor700ofFIG. 1Halso include capacitive nodes that have a capacitance that is different from that of other capacitive nodes. As an example, the capacitance of the capacitive nodes formed by the sense electrodes that are adjacent to edges404band404cmay have a capacitance that is less than the capacitance of capacitive nodes formed by the other sense electrodes. In particular embodiments, this capacitance difference may be the result of the sense electrodes that are adjacent to edges404band404conly having two spines, as opposed to three spines like the other sense electrodes that are not adjacent to edges404band404c. In particular embodiments, the sense electrodes adjacent to edges404band404cmay only have two spines (as opposed to three spines) as a result of edges404band404ccutting off the electrode pattern.

As another example, with regard to touch sensor700ofFIG. 1H(but not touch sensor600ofFIG. 1G), the capacitive nodes that are closest to edges404aand404dmay also have a capacitance that is less than that of capacitive nodes that are located farther away from edges404aand404d. In particular embodiments, similar to touch sensor500ofFIG. 1G, this difference in capacitance may be the result of the interdigitized drive sections of the drive electrodes of touch sensor700. For example, according to the illustrated embodiment, each drive electrode includes interdigitized drive sections. However, the drive electrodes that are adjacent to edges404aand404d(such as drive electrode408, which is adjacent to edge404a) do not have any interdigitized drive sections that face edges404aand404d. For example, there is no interdigitized drive sections in-between drive electrode408and edge404a. In certain embodiments, this lack of interdigitized drive sections is the result of the edges404aand404dcutting off the electrode pattern. Furthermore, this lack of interdigitized drive sections facing the edges404aand404dmay result in a lower capacitance at the capacitive nodes that are closest to these edges (e.g., the edge capacitive nodes). Accordingly, similar to the touch sensors ofFIGS. 1E and 1F, touch sensor600ofFIG. 1Gand touch sensor700ofFIG. 1Hmay also be deficient.

In particular embodiments, the deficiencies of touch sensor400ofFIG. 1E, touch sensor500ofFIG. 1F, touch sensor600ofFIG. 1G, touch sensor700ofFIG. 1H, and any other touch sensor that includes capacitive nodes that have a capacitance that is not approximately the same as that of the other capacitive nodes, may be reduced by a touch sensor that includes capacitive nodes that each have a capacitance that is approximately the same. In particular embodiments, capacitive nodes may each have a capacitance that is approximately the same when each capacitance is within the same operating limits. For example, capacitive nodes may each have a capacitance that is approximately the same when each capacitance is within 0.25 Picofarad (pF), 0.5 pF, 1.0 pF, or 5 pF. As another example, capacitive nodes may each have a capacitance that is approximately the same when each capacitance is within a difference of 10%. In particular embodiments, capacitive nodes may each have a capacitance that is approximately the same when each capacitances is the same. For example, capacitive nodes may each have a capacitance that is approximately the same when each capacitance is equal.

In particular embodiments, capacitive nodes of a touch sensor may each have a capacitance that is approximately the same when each capacitance of the edge capacitive nodes is increased (relative to that of the touch sensors ofFIGS. 1E-1H) so as to be approximately the same as that of the other capacitive nodes. In particular embodiments, the capacitances of the edge capacitive nodes may be increased (relative to that of the touch sensors ofFIGS. 1E-1H) to be approximately the same as that of the other capacitive nodes in any manner. For example,FIGS. 2A-2Gillustrate example electrode patterns of touch sensors that include edge capacitive nodes that each have a capacitance that has been increased so as to be approximately the same as that of the other capacitive nodes.

FIG. 2Aillustrates an electrode pattern800where each of the capacitive nodes have a capacitance that is approximately the same. In particular embodiments, electrode pattern800may be used in the touch sensors ofFIGS. 1E and 1F.

According to the illustrated embodiment, the capacitance of the edge capacitive nodes may be increased (relative to that of the touch sensors ofFIGS. 1E-1F) by adding additional conductive elements (relative to that of the touch sensors ofFIGS. 1E-1F) to the sense electrodes that are adjacent to the edges. For example, unlikeFIGS. 1E and 1Fwhere sense electrode412only includes two conductive elements (conductive elements428aand428b) in the proximity of capacitive node416, inFIG. 2A, sense electrode812includes three conductive elements (conductive element828a,828b, and828c) in the proximity of capacitive node816. In particular embodiments, the additional conductive element may result in the capacitance of capacitive node816being increased so as to be approximately the same as that of the other capacitive nodes farther away from edge804b.

In particular embodiments, the additional conductive element may result in adjacent conductive elements being closer together. For example, a sense electrode that is farther away from edge804bmay have two adjacent conductive elements that are separated by a gap with a first width, as is illustrated by first conductive element gap width844. Contrary to first conductive element gap width844, adjacent conductive elements on sense electrode812(such as conductive elements828band828c) may be separated by a gap with a second conductive element gap width846. In particular embodiments, second conductive element gap width846is less than first conductive element gap width844. In particular embodiments, second conductive element gap width846may have any size that is less that of first conductive element gap width844. For example, while first conductive element gap width844may be 5 mm, second conductive element gap width846may be 0.5 mm-2.5 mm, such as 1 mm. As another example, second conductive element gap width846may be less than 0.5 mm or greater than 2.5 mm. In particular embodiments, the size of second conductive element gap width846may be adjusted so as to cause the capacitance of capacitive node816to be approximately similar to that of other capacitive nodes.

AlthoughFIG. 2Aillustrates increasing the capacitance of capacitive node816by adding only a single additional conductive element in the proximity of capacitive node816, in particular embodiments, any number of conductive elements may be added in order to increase the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes of electrode pattern800(such as the capacitive nodes formed by sense electrodes that are farther away from edge804b). For example, two or more conductive elements may be added in order to increase the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes of electrode pattern800. Additionally, the location of each conductive element and the width of the gap between each adjacent conductive element (such as second conductive element gap width846) may be adjusted in any manner in order to increase the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes of electrode pattern800. AlthoughFIG. 2Aillustrates adding conductive elements in order to increase the capacitance of capacitive node816, in particular embodiments, conductive elements may be added to increase the capacitance of any (or all) of the edge capacitive nodes.

FIGS. 2B and 2Cillustrate electrode pattern900and electrode pattern1000where each of the capacitive nodes have a capacitance that is approximately the same. In particular embodiments, electrode pattern900may be used in the touch sensor ofFIG. 1Gand electrode pattern1000may be used in the touch sensor ofFIG. 1H.

According to the illustrated embodiments, the capacitance of the edge capacitive nodes may be increased (relative to that of the touch sensor ofFIGS. 1G-1H) by adding conductive elements to the sense electrodes that are adjacent to the edges. For example, unlikeFIGS. 1G and 1Hwhere sense electrode412does not include any conductive elements in the proximity of capacitive node416, inFIG. 2A, sense electrode812includes two conductive elements (conductive element828aand828b) in the proximity of capacitive node816. In particular embodiments, similar toFIG. 2A, the added conductive elements may result in the capacitance of capacitive node816being increased so as to be approximately the same as that of the other capacitive nodes farther away from edge804b.

Furthermore, according toFIG. 2C, the capacitance of the capacitive nodes that are closest to edges804aand804d(not illustrated) may also be increased (relative to that of the touch sensor ofFIG. 1H) by adding conductive elements near these capacitive nodes. For example, as is illustrated inFIG. 2C, conductive elements828c,828d,828e, and828fare added to the sense electrodes that are not adjacent to edges804band804c. These additional conductive elements may increase the capacitance of the capacitive nodes closest to edges804aand804d. As such, despite the fact that a touch sensor may include interdigitized drive sections and sense electrodes in a trident pattern, the capacitive nodes closest to edges804aand804dmay be approximately the same as that of the other capacitive nodes in the touch sensor.

AlthoughFIGS. 2B and 2Cillustrate increasing the capacitance of capacitive node816by adding only two conductive elements in the proximity of capacitive node816, in particular embodiments, any number of conductive elements may be added in order to increase the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes of electrode patterns900and1000(such as the capacitive nodes formed by sense electrodes that are farther away from edge804b). For example, three or more conductive elements (or even only one conductive element) may be added in order to increase the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes of electrode patterns900and1000. Additionally, the location of each conductive element and the width of the gap between each adjacent conductive element may be adjusted in any manner in order to increase the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes of electrode patterns900and1000. AlthoughFIG. 2Aillustrates adding conductive elements in order to increase the capacitance of capacitive node816, in particular embodiments, conductive elements may be added to increase the capacitance of any (or all) of the edge capacitive nodes.

FIG. 2Dillustrates an electrode pattern1100where each of the capacitive nodes have a capacitance that is approximately the same. In particular embodiments, electrode pattern1100may be used in the touch sensors ofFIGS. 1E and 1F.

According to the illustrated embodiment, the capacitance of the edge capacitive nodes may be increased (relative to that of the touch sensors ofFIGS. 1E-1F) by increasing the width of the conductive elements (relative to that of the touch sensors ofFIGS. 1E-1F) of the sense electrodes that are adjacent to the edges. For example, the capacitance of capacitive node816may be increased by increasing the width of conductive element828bof sense electrode812. In particular embodiments, the increased width may result in the capacitance of capacitive node816being increased to be approximately the same as that of the other capacitive nodes farther away from edge804b.

In particular embodiments, increasing the width of the conductive elements may include increasing the width of the conductive elements to any size. For example, a sense electrode that is farther away from edge804bmay have a conductive element with a first width, as is illustrated by first conductive element width848. Contrary to first conductive element width848, one or more of the conductive elements of sense electrode812may have a second conductive element width850. In particular embodiments, second conductive element width850is greater than first conductive element width848. In particular embodiments, second conductive element width850may have any size that is greater than that of first conductive element width848. For example, while first conductive element width848may be 0.3 mm-1.0 mm, second conductive element width850may be 1.0 mm-2.0 mm. As another example, second conductive element width850may be less than 1.0 mm or greater than 2.0 mm. In particular embodiments, the size of second conductive element width850may be adjusted so as to cause the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes.

In particular embodiments, adjusting the width of each conductive element may further include adjusting the location of each conductive element. In particular embodiments, the location of each conductive element may be adjusted to any location so as to cause the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes. AlthoughFIG. 2Dillustrates increasing the width of a conductive element in order to increase the capacitance of capacitive node816, in particular embodiments, the width of the conductive elements may be increased in order to increase the capacitance of any (or all) of the edge capacitive nodes.

FIG. 2Eillustrates an electrode pattern1200where each of the capacitive nodes have a capacitance that is approximately the same. In particular embodiments, electrode pattern1200may be used in the touch sensors ofFIGS. 1E,1F,1G, and1H.

According to the illustrated embodiment, the capacitance of the edge capacitive nodes may be increased (relative to that of the touch sensors ofFIGS. 1E-1H) by adding an additional spine (relative to that of the touch sensors ofFIGS. 1E-1H) to the sense electrodes that are adjacent to the edges. For example, unlikeFIGS. 1E and 1Fwhere sense electrode412only includes a single spine420, inFIG. 2E, sense electrode812includes two spines (spine820aand spine820b). In particular embodiments, the additional spine may result in the capacitance of capacitive node816being increased to be approximately the same as that of the other capacitive nodes farther away from edge804b.

In particular embodiments, the additional spine may result in adjacent spines being closer together. For example, adjacent spines of sense electrodes that are farther away from edge804bmay be separated by a gap with a first width, as is illustrated by first spine gap width836. Contrary to first spine gap width836, the two adjacent spines that are closest to the edge (such as spine820aand spine820b) may be separated by a gap with a second spine gap width838. In particular embodiments, second spine gap width838is less than first spine gap width836. In particular embodiments, second spine gap width838may have any size that is less than first spine gap width836. For example, while first spine gap width836may be 6 mm-12 mm, second spine gap width838may be 1 mm-5 mm. As another example, second spine gap width838may be less than 1 mm or greater than 5 mm. In particular embodiments, the size of second spine gap width838may be adjusted so as to cause the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes.

AlthoughFIG. 2Eillustrates increasing the capacitance of capacitive node816by adding only a single additional spine to sense electrode812, in particular embodiments, any number of spines may be added in order to increase the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes of electrode pattern1200(such as the capacitive nodes formed by sense electrodes that are farther away from edge804b). For example, two or more spines may be added in order in order to increase the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes of electrode pattern1200. Additionally, the location of each of the spines and the width of the gap between each adjacent spine (such as second spine gap width838) may be adjusted in any manner in order to increase the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes of electrode pattern1200. AlthoughFIG. 2Eillustrates adding spines in order to increase the capacitance of capacitive node816, in particular embodiments, spines may be added to increase the capacitance of any (or all) of the edge capacitive nodes.

FIG. 2Fillustrates an electrode pattern1300where each of the capacitive nodes have a capacitance that is approximately the same. In particular embodiments, electrode pattern1200may be used in the touch sensors ofFIGS. 1E and 1F.

According to the illustrated embodiment, the capacitance of the edge capacitive nodes may be increased (relative to that of the touch sensors ofFIGS. 1E-1F) by increasing the width of the spine (relative to that of the touch sensors ofFIGS. 1E-1F) of the sense electrodes that are adjacent to the edges. For example, the capacitance of capacitive node816may be increased by increasing the width of spine820of sense electrode812. In particular embodiments, the increased width may result in the capacitance of capacitive node816being increased to be approximately the same as that of the other capacitive nodes farther away from edge804b.

In particular embodiments, increasing the width of the spines may include increasing the width of the spines to any size. For example, a sense electrode that is farther away from edge804bmay have a spine with a first width, as is illustrated by first spine width840. Contrary to first spine width840, the spine of sense electrode812may have a second spine width842. In particular embodiments, second spine width842is greater than first spine width840. In particular embodiments, second spine width842may have any size that is greater than that of first spine width840. For example, while first spine width842may be 0.5 mm-1.5 mm, second spine width842may be 1 mm-2 mm. As another example, second spine width842may be less than 1 mm or greater than 2 mm. In particular embodiments, the size of second spine width842may be adjusted so as to cause the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes.

In particular embodiments, adjusting the width of a spine may further include adjusting the location of the spine. In particular embodiments, the location of spine820may be adjusted to any location so as to cause the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes. AlthoughFIG. 2Fillustrates increasing the width of a spine in order to increase the capacitance of capacitive node816, in particular embodiments, the width of the spines may be increased in order to increase the capacitance of any (or all) of the edge capacitive nodes.

FIG. 2Gillustrates an electrode pattern1400where each of the capacitive nodes have a capacitance that is approximately the same. In particular embodiments, electrode pattern1400may be used in the touch sensors ofFIGS. 1G and 1H.

According to the illustrated embodiment, the capacitance of the edge capacitive nodes may be increased (relative to that of the touch sensors ofFIGS. 1G-1H) by increasing the width of a spine (relative to that of the touch sensors ofFIGS. 1G-1H) of the sense electrodes that are adjacent to the edges. For example, the capacitance of capacitive node816may be increased by increasing the width of spine820of sense electrode812. In particular embodiments, the increased width may result in the capacitance of capacitive node816being increased to be approximately the same as that of the other capacitive nodes farther away from edge804b.

In particular embodiments, increasing the width of the spines may include increasing the width of the spines to any size. For example, a sense electrode that is farther away from edge804bmay have a spine with a first width, as is illustrated by first spine width840. Contrary to first spine width840, a spine of sense electrode812may have a second spine width842. In particular embodiments, second spine width842is greater than first spine width840. In particular embodiments, second spine width842may have any size that is greater than that of first spine width840. For example, while first spine width842may be 0.5 mm-1.5 mm, second spine width842may be 1 mm-2 mm. As another example, second spine width842may be less than1mm or greater than 2 mm. In particular embodiments, the size of second spine width842may be adjusted so as to cause the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes.

In particular embodiments, adjusting the width of a spine may further include adjusting the location of the spine. In particular embodiments, the location of spine820may be adjusted to any location so as to cause the capacitance of capacitive node816to be approximately the same as that of the other capacitive nodes. AlthoughFIG. 2Gillustrates increasing the width of a spine in order to increase the capacitance of capacitive node816, in particular embodiments, the width of the spines may be increased in order to increase the capacitance of any (or all) of the edge capacitive nodes.

Modifications, additions, or omissions may be made to the electrode patterns ofFIGS. 2A-2Gwithout departing from the scope of the disclosure. For example, although each ofFIGS. 2A-2Gillustrates a particular embodiment for causing the capacitance of each of the capacitive nodes to be approximately the same, in particular embodiments, one or more of the particular embodiments illustrated inFIGS. 2A-2Gmay be combined in order to cause the capacitance of each of the capacitive nodes to be approximately the same. In particular, additional conductive elements may be added, and the width of the conductive elements may be increased. Furthermore, additional spines may be added, and the width of the spines may be increased. Additionally, any other combination ofFIGS. 2A-2Gmay be used. As another example, although the embodiments ofFIGS. 2A-2Ghave been illustrated as applying to particular touch sensor configurations and particular touch sensor electrode patterns, the embodiments ofFIGS. 2A-2Gmay be applied to any configuration for a touch sensor and any electrode pattern for a touch sensor. For example, the embodiments ofFIGS. 2A-2Gmay be applied to any electrode patterns in both single-layer configurations and two-layer configurations of touch sensors, and may further be applied to any touch sensor that includes capacitive nodes that have a capacitance that is not approximately the same as that of the other capacitive nodes.

FIG. 3illustrates a device1500that may incorporate any of the touch sensors and electrode patterns ofFIGS. 1A-2G. Device1500may include a desktop computer, laptop computer, tablet computer, personal digital assistant (PDA), Smartphone, satellite navigation device, telephone, cell phone, portable media player, portable game console, kiosk computer, point-of-sale device, household appliance, automatic teller machine (ATM), any other device, or any combination of the preceding.

According to the illustrated embodiment, device1500includes a touch screen display1504. Touch screen display1504enables the touch screen to present a wide variety of data, including a keyboard, a numeric keypad, program or application icons, and various other interfaces as desired. The user may interact with device1500by touching touch screen display1504with a single finger (or any other object), such as to select a program for execution or to type a letter on a keyboard displayed on the touch screen display1504. In addition, the user may use multiple touches, such as to zoom in or zoom out when viewing a document or image. In particular embodiments of device1500, such as home appliances, touch screen display1504may not change or may change only slightly during device operation, and may recognize only single touches.