Touch sensor device having a circular touch sensing area

A touch sensor device includes a touch sensing area including touch sensors sequentially disposed in a first direction extending away from an imaginary central point, in which an area of each touch sensors gradually increases as a distance thereof away from the imaginary center point increases, at least one of the touch sensors includes a first touch electrode and a second touch electrode adjacent to each other, a width of the first touch electrode decreases along a second direction, and a width of the second touch electrode increases along the second direction.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean Patent Application No. 10-2015-0044556, filed on Mar. 30, 2015, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND

Exemplary embodiments of the present invention relate to a touch sensor device, and more particularly, to a touch sensor device including a circular touch sensing area and a display device including the same.

2. Discussion of the Background

An electronic device, such as a liquid crystal display (LCD), an organic light emitting diode (OLED) display, and an electrophoretic display may include a touch sensing function, such that a user may interact with the electronic device. The touch sensing function may determine whether a user finger, etc., touches a screen, and touch position information thereof, by sensing a change of pressure, light, etc., that occurs on a screen in the display device, when the user contacts the finger or a touch pen to the screen to write a character or to draw a picture.

The touch sensing function may be realized through a touch sensor. The touch sensor may be classified into various types, such as a resistive type, a capacitive type, an electro-magnetic (EM) type, and an optical type.

The capacitive touch sensor may include a sensing capacitor formed by a sensing electrode that may transfer a sensing signal, and sense a change in capacitance of the sensing capacitor generated when a conductor such as a finger approaches the touch sensor, to determine existence of a touch, a touch position, and the like. The capacitive touch sensor may include touch electrodes disposed in a touch sensing area sensing the touch, and touch wires connected to the touch electrodes. The touch wires may transmit a sensing input signal to the touch electrode and transmit a sensing output signal of the touch electrode generated depending on the touch to a touch driver.

The touch sensor may be installed in the display device (an in-cell type), may be formed on an outer surface of the display device (an on-cell type), or may be attached to a separate touch sensor panel of the display device (an add-on cell type).

A touch electrode constituting a touch sensor may be disposed at a touch sensing area that may sense a touch, and the touch sensing area may overlap with a display area for displaying an image in a display device.

SUMMARY

Exemplary embodiments of the present invention provide a touch sensor device, and a display device including the same, of which a structure of the touch sensor device includes a touch sensing area having a non-quadrangular (e.g., circular or elliptical) shape that may be capable of sensing multiple touches, precisely sense a touched position, and increase price competitiveness.

According to an exemplary embodiment of the present invention, a touch sensor device includes a touch sensing area including touch sensors sequentially disposed in a first direction extending away from an imaginary central point, in which an area of each touch sensors gradually increases as a distance thereof away from the imaginary central point increases, at least one of the touch sensors includes a first touch electrode and a second touch electrode adjacent to each other, a width of the first touch electrode decreases along a second direction, and a width of the second touch electrode increases along the second direction.

The second direction may be a clockwise or counterclockwise direction with respect to the imaginary central point.

The touch sensing area may be divided into domains by at least one imaginary boundary line, and the touch sensors may be respectively disposed in each domain.

An outer side edge of the touch sensor may together form a circle, an ellipse, or an arc with respect to the imaginary central point.

The first touch electrode and the second touch electrode may be disposed on the same layer, and may include the same material.

The touch sensor device may further include touch wires connected to the touch sensors, and at least one touch driver connected to the touch wires.

A first portion of the touch wires may be disposed in a peripheral area outside the touch sensing area.

A second portion of the touch wires may be disposed in a boundary area between adjacent domains.

The touch wires may be disposed on the same layer as the first and second touch electrodes, and may include the same material as the first and second touch electrodes.

The touch wires may be connected to a side of the first or second touch electrode having a greater width.

The touch sensor device may further include touch wires connected to the touch sensors, touch drivers connected to the touch wires and disposed in a peripheral area outside the touch sensing area, in which each of the touch drivers may be disposed in a boundary area between adjacent domains.

The touch sensors may include a first touch sensor disposed closest to the imaginary central point, and the first touch sensor may include one touch electrode.

The touch electrode of the first touch sensor may have a substantially circular or fan shape.

The touch sensing area may be divided into domains by at least one imaginary boundary line, and the touch sensors may be respectively disposed in each domain.

An outer side edge of the first touch sensor may form an arc with respect to the imaginary central point.

According to the exemplary embodiments of the present invention, the touch sensor device and the display device including the same may have increased price competitiveness.

Further, a structure of the touch sensor device may provide a touch sensing area having a non-quadrangular (e.g., circular or elliptical) shape. In addition, the touch sensor device including the touch sensing area having the non-quadrangular (e.g., circular or elliptical) shape may sense touches made at multiple regions.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

A display device according to exemplary embodiments of the present invention will be described with reference toFIG. 1toFIG. 12.

FIG. 1is a top plan view of a touch sensor device according to an exemplary embodiment of the present invention.

Referring toFIG. 1, the touch sensor device1according to the present exemplary embodiment may sense a contact made by an external object. The contact may include a direct touch, in which an external object such as a user's finger directly touches a touch surface of the touch sensor device1, and a hovering touch, in which the external object approaches the touch sensor device1or hovers after the external object has approached the touch sensor device1.

The touch sensor device1includes a touch sensing area TA that may sense a contact made by an external object and a peripheral area PA positioned outside the touch sensing area TA, i.e., a periphery of the touch sensing area TA. The peripheral area PA may be referred to as a dead space. The peripheral area PA may not sense most contacts.

In the touch sensor device1of the present exemplary embodiment, a shape of the touch sensing area TA may be circular or elliptical.

An imaginary central point “O” may be disposed at the center of the touch sensing area TA, and may be divided into domains A1, A2, A3, and A4by at least one of imaginary boundary lines CL1and CL2that extend through the central point O. When the touch sensing area TA has a circular shape, the central point O may be the center of the circular shape.FIG. 1illustrates an example in which the touch sensing area TA is divided into four domains A1, A2, A3, and A4by two boundary lines CL1and CL2that extend through the central point O. When the two boundary lines CL1and CL2that extend through the central point O are perpendicular to each other, areas of the divided domains A1, A2, A3, and A4may be substantially the same.

Boundary areas B1, B2, B3, and B4serving as peripheral areas of the boundary lines CL1and CL2that extend through the central point O may be formed between the adjacent domains A1, A2, A3, and A4.

A touch sensor may be disposed at each of the domains A1, A2, A3, and A4of the touch sensing area TA, and shapes, dispositions, and the like of touch electrodes included in the touch sensors positioned at the respective domains may be the same. Alternatively, shapes, dispositions, and the like of the touch electrodes included in the touch sensors positioned at the respective domains may be different from each other.

The touch sensors positioned at one domain A1, A2, A3, or A4include touch sensors110,120,130,140,150, and160, which are sequentially positioned to be further away from the central point O to the outside. According to an exemplary embodiment of the present invention, the number of the touch sensors may be increased or reduced according to a size, a touch resolution, or the like of the touch sensor device1.

External or internal edges of the touch sensors110,120,130,140,150, and160are curvedly formed, thereby constituting a circle, an ellipse, or an arc, or a bent edge having at least one vertex. When the touch sensing area TA has a substantially circular shape, a distance from the central point to the internal or external edge of each of the touch sensors110,120,130,140,150, and160may be substantially constant.

A width of each of the touch sensors110,120,130,140,150, and160may be substantially constant. However, widths of the touch sensors110,120,130,140,150, and160positioned at each of the domains A1, A2, A3, and A4may be the same or different from each other according to the position from the central point O. Herein, the widths of the touch sensors110,120,130,140,150, and160may indicate a width of a half-line direction that starts from the central point O. When the widths of the touch sensors110,120,130,140,150, and160positioned at each of the domains A1, A2, A3, and A4are different from each other, the widths of the touch sensors110,120,130,140,150, and160may be gradually increased or reduced farther away from the central point O.

The areas of the touch sensors110,120,130,140,150, and160may be gradually widened as they are farther away from the central point O. As a result, at each of the domains A1, A2, A3, and A4, the first touch sensor110may have the smallest area, while the touch sensor150which is farthest away from the central point O may have the largest area.

The touch sensors110,120,130,140,150, and160of different domains A1, A2, A3, and A4, which are positioned in substantially the same order from the central point O may be substantially aligned at boundaries between the domains A1, A2, A3, and A4. Particularly, when viewed from the touch sensing area TA, the touch sensors110,120,130,140,150, and160positioned in substantially the same order from the central point O may be disposed substantially concentrically.

The first touch sensor110positioned closest to the central point O may have a circular or fan shape. As shown inFIG. 1, when generally viewed from the touch sensing area TA, the first touch sensors110may be formed together as a circle.

The touch sensors110,120,130,140,150, and160positioned at substantially the same position from the central point O are physically and electrically separated from each other.

Each of the touch sensors110,120,130,140,150, and160may include one touch electrode or a multiple touch electrodes. Referring toFIG. 1according to the present exemplary embodiment, each of the touch sensors120,130,140,150, and160, except for the first touch sensor110, includes multiple touch electrodes.

Referring toFIG. 1, each of the touch sensors120,130,140,150, and160, except for the first touch sensor110, may include pairs of touch electrodes120aand120b,130aand130b,140aand140b,150aand150b, and160aand160b, respectively, which are adjacent to and face each other.

The pairs of touch electrodes120aand120b,130aand130b,140aand140b, and150aand150b,160aand160b, which are disposed to face each other included in each of the touch sensors120,130,140,150, and160, except for the first touch sensor110, have similar characteristics, and thus one touch sensor, e.g., the pair of touch electrodes120aand120bincluded in the second touch sensor120, will be described hereinafter.

The width of a first touch electrode120aof the pairs of the touch electrodes120aand120bis reduced in a first longitudinal direction, and the width of a second touch electrode120bis reduced in a second longitudinal direction opposite to the first longitudinal direction. The touch sensor120is formed to have a substantially arch shape with respect to the central point O. Accordingly, the width of the first touch electrode120ais gradually reduced in a clockwise direction with respect to the central point O and the width of the second touch electrode120bis gradually reduced substantially in a counterclockwise direction. More particularly, in a first direction among the directions in which azimuthal angles are changed, the width of the first touch electrode120amay be reduced and the width of the second touch electrode120bmay be increased.

The distance between the first touch electrode120aand the second touch electrode120bmay be constant. Each of the first and second touch electrodes120aand120bmay be formed to have a bent wedge or sickle shape, or a substantially triangular shape with respect to the central point O.

The first touch sensor110may include one touch electrode. The first touch sensors110positioned at the respective domains A1, A2, A3, and A4may be formed to have a fan shape. Areas of the touch electrodes included in the first touch sensors110and the touch electrodes120aand120b,130aand130b,140aand140b,150aand150b, and160aand160bincluded in the touch sensors120,130,140,150, and160may be increased as a distance thereof to the central point O increases.

The touch sensor device1includes touch wires200connected to the touch electrodes included in the first touch sensors110and the touch electrodes120aand120b,130aand130b,140aand140b,150aand150b, and160aand160bincluded in the touch sensors120,130,140,150, and160. The touch wires200may include portions positioned in boundary areas B1, B2, B3, and B4formed between the adjacent domains A1, A2, A3, and A4and/or portions positioned in the peripheral area PA.

The touch wires200may be connected to at least one touch driver500to receive driving signals or transfer touch signals generated according to touch sensing. The touch driver500may be disposed in the peripheral area PA. More specifically, the touch drivers500may be disposed in the peripheral area PA to correspond to regions formed between the adjacent domains A1, A2, A3, and A4. The touch driver500may include a circuit board and a driving circuit mounted or formed therein, or may be configured in various forms including a driving circuit integrated in the peripheral area PA.

For convenience of illustration,FIG. 1illustrates portions of the touch wires200positioned in the peripheral area PA, but the remaining touch wires200extend from the illustrated portions to be connected to the touch driver500. Particularly, as shown inFIG. 1, when the touch driver500is disposed at a region corresponding to the imaginary boundary line CL2, the touch wire200including a portion thereof positioned in the boundary area B4close to the touch driver500may be directly connected to the touch driver500without extending toward the peripheral area PA.

The touch wires200connected to the touch electrodes120a,120b,130a,130b,140a,140b,150a,150b,160a, and160bmay be connected to sides of the touch electrodes120a,120b,130a,130b,140a,140b,150a,150b,160a, and160b, which have the greatest widths.

Referring toFIG. 1andFIG. 2, in a cross-sectional view of the touch sensor device1, the touch sensors110,120,130,140,150, and160, and the touch wires200may be formed on the substrate10. The substrate10may be an additional substrate included in the touch sensor device1, or a substrate or an insulating layer included in an electronic device, e.g., a display device, including the touch sensor device1. The substrate10may be a flexible film, or may have rigidity.

The touch electrodes included in the touch sensors110,120,130,140,150, and160may have more than a predetermined transmittance rate to transmit light. For example, the touch electrode may include a transparent conductive oxide, such as indium tin oxide (ITO) and indium zinc oxide (IZO). However, the touch electrodes may include at least one of a transparent conductive material, such as a metal nanowire, a conductive polymer such as is PEDOT, a metal mesh, carbon nanotubes (CNT), and a thin metal layer.

All of the touch electrodes included in the touch sensors110,120,130,140,150, and160may be disposed at the same layer, and may be formed by using the same material.

The touch wires200may be disposed at the same layer as that of the touch sensors110,120,130,140,150, and160, may be formed by using the same material, or may be disposed at different layers. According to the present exemplary embodiment illustrated with reference toFIG. 2, the touch wires200are disposed at the same layer as that of the touch electrodes, and are formed by using the same material.

Hereinafter, a method of sensing a touch by the touch sensor device1according to an exemplary embodiment of the present invention will be described.

According to the present exemplary embodiment, the touch sensors110,120,130,140,150, and160may be capacitive-type touch sensors. The touch electrodes included in the touch sensors110,120,130,140,150, and160may be charged with a predetermined amount of charges by receiving a driving signal from the touch driver500. The charged amount is changed when a contact is made by an external object such as a finger, and thus a corresponding touch signal is outputted to the touch driver500through the touch wires200. The touch driver500may determine contact information such as a contact state or a contact position. The touch sensors may be referred to as a self-capacitance type.

Particularly, when the touch sensors120,130,140,150, and160include the pair of the touch electrodes120aand120b,130aand130b,140aand140b,150aand150b,160aand160b, of which widths of the pair of the electrodes are changed in the opposite direction, angles of a clockwise or counterclockwise direction at touch positions of the corresponding touch sensors120,130,140,150, and160may be precisely distinguished.

Hereinafter, a case in which the touch sensor120is touched by an external object, e.g., a method for distinguishing a touch position, will be described.

When an external object contacts a region of the touch sensor120to form a touch area, the touch area may include a first area overlapping the first touch electrode120aand a second region overlapping the second touch electrode120b. In the first area, the finger and the first touch electrode120amay constitute a first capacitor, and in the second area, the finger and the second touch electrode120bmay constitute a second capacitor. Capacitances of the first capacitor and the second capacitor are respectively proportional to the areas of the first area and the second area.

The widths of the first and second touch electrodes120aand120bare gradually changed along the clockwise or counterclockwise direction with respect to the central point O. Accordingly, when the external object touches different areas of the touch sensor120, the capacitances and changes of the charged amounts in the first capacitor and the second capacitor may be different in each touched areas. Accordingly, an azimuthal angle from a reference line of the touch position in the touch sensor120, e.g., an angle from the imaginary boundary lines CL1and CL2, may be sensed by using the differences.

Further, touches made at positions having different distances from the central point O may be distinguished by concentrically disposing the touch sensors110,120,130,140,150, and160at different distances from the central points.

Accordingly, a touch position in the touch sensing area TA may be precisely determined, as polar coordinates, i.e., both a distance (referred to as a radius) from the central point O and an angle (referred to as an azimuthal angle) from an initial line may be sensed. Further, since the touch position is determined by using polar coordinates, which may be implemented on the touch sensor device1that has the touch sensing area TA of a non-quadrangular, particularly, circular shape, a user interface/experience (UI, UX) appropriate for a circular touch sensor device may be embodied.

FIG. 3andFIG. 4illustrate a display device including a touch sensor device according to an exemplary embodiment of the present invention.

A display device1000including the touch sensor device according to the present exemplary embodiment may include a display area corresponding to the non-quadrangular (e.g., circular or elliptical) touch sensing area TA. The display area may have an area positioned at the peripheral area PA. Icons300serving as user interfaces may be displayed on the display area TA. When the touch sensing area TA and the display area have circular shapes, the icons300may have circular shapes for convenient touches of users. When polar coordinates are employed to recognize a touch position in the display device1000, the touch position may be determined precisely in most regions of the touch sensing area TA and a driving method of the touch sensor device may be simplified.

According to the present exemplary embodiment, all electrodes included in the touch sensors110,120,130,140,150, and160may be positioned at the same layer and formed by using the same layer, thereby constituting a single layer. Accordingly, a manufacturing process and time may be reduced, thereby increasing price competitiveness thereof as compared with conventional touch sensors that are disposed at multiple layers.

According to the exemplary embodiment illustrated inFIG. 1, the touch sensing area TA is divided into four domains A1, A2, A3, and A4by two imaginary boundary lines CL1and CL2extending through the central point O. However, the number of domains may be determined according to conditions such as user interfaces, driving methods, and the like. Particularly, when the number of domains A1, A2, A3, and A4is determined as four or more, the touch position may be precisely recognized.

Hereinafter, a touch sensor device according to an exemplary embodiment of the present invention will be described with reference toFIG. 5as well as the aforementioned drawings.

FIG. 5is a top plan view illustrating a touch sensor device according to an exemplary embodiment of the present invention.

Referring toFIG. 5, a touch sensor device1according to the present exemplary embodiment is substantially the same as the touch sensor device illustrated with reference to FIG.1andFIG. 2, except that the touch sensor device1may include touch drivers500aand500bfor driving the touch sensors. More particularly, the touch drivers may be disposed at multiple positions.

Referring toFIG. 5, the touch sensor device1includes two touch drivers500aand500b. However, the touch sensor device1may include three or more touch drivers. A first touch driver500amay be disposed at a portion corresponding to the imaginary boundary line CL2in the peripheral area PA, and a second touch driver500bmay be disposed at a portion corresponding to the imaginary boundary line CL1in the peripheral area PA.

When the touch sensor device1includes touch drivers500aand500bpositioned at different areas of the touch sensor device1, the number of touch wires200formed in the peripheral area PA may be reduced, thereby reducing an area of the peripheral area PA of the touch sensor device1. As a result, it may possible to implement a narrow bezel.

Hereinafter, a touch sensor device according to an exemplary embodiment of the present invention will be described with reference toFIG. 6as well as the aforementioned drawings.

FIG. 6is a top plan view illustrating a touch sensor device according to an exemplary embodiment of the present invention.

Referring toFIG. 6, the touch sensor device1according to the present exemplary embodiment is substantially the same as the touch sensor device illustrated inFIG. 1andFIG. 2, except that the touch sensing area TA is divided into two domains A5and A6by one boundary line CL1.

The two divided domains A5and A6may have substantially the same areas, and may be formed to be symmetrical to each other. Boundary areas B1and B3serving as peripheral areas of the boundary line CL1extending through the central point O may be formed between the adjacent domains A5and A6. A touch sensor is disposed at each of the domains A5and A6of the touch sensing area TA.

The touch sensor disposed at each of the domains A5and A6includes touch sensors110,120, . . . , and160, which are disposed sequentially from the central point O toward the outside. Each of the touch sensors110,120, . . . , and160may have a semi-circular or semi-arc shape. Areas of the touch sensors110,120, . . . , and160may be increased as they are positioned farther away from the central point O.

The touch sensor device1includes touch wires200connected to the touch electrodes included in the first touch sensor110and a pair of the touch electrodes120a,120b, . . . ,160a, and160brespectively included in the touch sensors120, . . . , and160. The touch wires200may include portions positioned in the boundary area B1and B3and/or portions positioned in the peripheral area PA.

The touch wires200may be connected to the touch driver500disposed in the peripheral area PA. The touch driver500may be disposed in the peripheral area PA corresponding to a region between the adjacent domains A5and A6.

The touch wires20connected to the touch electrodes120a,120b, . . . ,160a, and160bmay be connected to a widest portion of each of the touch electrodes120a,120b, . . . ,160a, and160b.

The aforementioned characteristics and effects of the touch sensor device and the display device including the same illustrated with reference toFIGS. 1 to 5may be applicable to the present exemplary embodiment illustrated inFIG. 6.

Exemplary embodiments of the present invention illustrated with reference toFIGS. 1 to 6include a touch sensor device, which are divided into multiple by at least one imaginary boundary line CL1and CL2. However, according to an exemplary embodiment of the present invention, the touch sensing area TA may exclusively include one domain, and may include multiple touch sensors disposed at different distances from the central point O. The touch sensors may be disposed in a concentric form including different radiuses, and each of the touch sensors may include a pair of touch electrodes, which are disposed to face each other and have widths that are changed. In this case, each of the touch electrodes may be formed at an azimuthal angle that is substantially close to 360 degrees, and widths thereof may be changed according to the azimuthal angle. Further, the first touch sensor110which is closest to the central point O may have a substantially circular shape.

Other characteristics are the same as those of the aforementioned exemplary embodiments, and thus repeated description thereof will be omitted.

Although certain exemplary embodiments and implementations have been described herein, other embodiments and modifications will be apparent from this description. Accordingly, the inventive concept is not limited to such exemplary embodiments, but rather to the broader scope of the presented claims and various obvious modifications and equivalent arrangements.