Touch electrode layer and touch display device

The invention provides a touch electrode layer and a touch display device, including a first electrode and a second electrode. The first electrode has a first electrode stem and a plurality of first electrode branches arranged obliquely along the first electrode stem. The second electrode has a second electrode stem and a plurality of second electrode branches arranged obliquely along the second electrode stem. The first electrode and the second electrode are arranged in a symmetrical structure, and inclination angles of the first electrode branches and the second electrode branches are same. In a touch electrode unit, shape and size of the first electrode and the second electrode are almost same, and shape and size of the first electrode branches and the second electrode branches that are staggered are also almost the same.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority of a Chinese patent application filed on Sep. 26, 2019 with the National Intellectual Property Administration, application number 201910915878.0, titled “Touch electrode layer and touch display device”, which is incorporated by reference in the present application in its entirety.

FIELD OF INVENTION

The invention relates to the field of touch display, in particular to a touch electrode layer and a touch display device.

BACKGROUND OF INVENTION

Capacitive touch screens are widely used in various electronic interactive scene devices due to their high durability, long life, and support for multi-touch functions. The capacitive touch screens detect a specific position touched by a finger by detecting a change in capacitance at the position touched by the finger. Therefore, when an amount of change in capacitance caused by a touch is small, conventional capacitive touch screens may not be able to accurately detect whether there is a touch input or not.

Technical Problem

Since structural design of the touch screens is a very important factor in detecting the change in capacitance, it is necessary to develop a touch screen design that can detect a small change in capacitance. At present, for active-matrix organic light-emitting diode (AMOLED) display screens, touch electrode patterns usually need to be directly fabricated on an upper surface of a thin film encapsulation layer. However, due to a thickness of the encapsulation layer being thinner (generally less than 10 um), a distance between a touch electrode and a cathode is small, which results in a large parasitic capacitance between a driving electrode (TX) and/or a sensing electrode (RX) and the cathode, which causes a large RC delay and reduces control sensitivity. Moreover, in current flexible AMOLED display screens, material of the touch electrode is usually a hollow metal grid. Its actual effective conductive electrode area is relatively smaller than that of a traditional touch electrode having full-surface transparent indium tin oxide (ITO). Therefore, a mutual induction capacitance between the touch electrodes TX and RX is very small, which results in a smaller capacitance change caused by a touch, which is not easily detected by a touch chip.

Therefore, it is urgent to provide a new touch electrode layer and a touch display device to improve resolution and accuracy of touch position detection of the touch display devices.

SUMMARY OF INVENTION

Technical Solutions

An object of the present invention is to provide a touch electrode layer and a touch display device. It can effectively improve a mutual capacitance value between a touch drive electrode and a touch sensing electrode, also to make the distribution of a mutual capacitance electric field in an entire touch screen structure more uniform, which is more conducive to improve resolution and accuracy of a touch position detection.

In order to achieve the above object, the present invention provides a touch electrode layer including a plurality of first electrode chains disposed along a first direction, each of the first electrode chains including a plurality of first electrodes electrically connected to each other; and a plurality of second electrode chains disposed along a second direction, each of the second electrode chains including a plurality of second electrodes electrically connected to each other, and each of the first electrode chains and each of the second electrode chains insulated from each other; wherein each of the first electrodes intersects with one of the second electrodes corresponding to the first electrode to form a touch electrode unit, each of the first electrodes includes a first electrode stem and a plurality of first electrode branches, each of the first electrode branches is obliquely connected to the first electrode stem; and each of the second electrodes includes a second electrode stem and a plurality of second electrode branches, each of the second electrode branches is obliquely connected to the second electrode stem, each of the first electrode branches and each of the second electrode branches are staggered and insulated from each other, and each of the first electrode branches is arranged in a gap between two adjacent second electrode branches.

Furthermore, the touch electrode layer further including a third electrode insulated from the first electrodes and the second electrodes, and disposed between the first electrode branches and the second electrode branches.

Furthermore, the first electrode stem includes a first longitudinal electrode stem and two first lateral electrode stems respectively positioned at two ends of the first longitudinal electrode stem, the first longitudinal electrode stem is vertically connected to the two first lateral electrode stems, and the first electrode branches are all obliquely connected to the first longitudinal electrode stem or the first lateral electrode stems.

Furthermore, the second electrode stem includes a second lateral electrode stem and two second longitudinal electrode stems respectively positioned at two ends of the second lateral electrode stem, the second lateral electrode stem is vertically connected to the two second longitudinal electrode stems, and the second electrode branches are all obliquely connected to the second longitudinal electrode stems or the second lateral electrode stem.

Furthermore, the first longitudinal electrode stem intersects with the second lateral electrode stem to form a crossing region, and each of the first electrodes and each of the second electrodes are insulated from each other in the crossing region.

Furthermore, the first longitudinal electrode stem includes an upper electrode stem, a lower electrode stem, and a first connection portion connecting the upper electrode stem and the lower electrode stem; the upper electrode stem is up-down symmetrical with the lower electrode stem; and a part of the first electrode branches is connected to each other through the upper electrode stem and one of the first lateral electrode stems, and the other part of the first electrode branches is connected to each other through the lower electrode stem and another one of the first lateral electrode stems.

Furthermore, a plurality of first intermediate portions are disposed between the first electrode branches and the first electrode stem; and a plurality of second intermediate portions are disposed between the second electrode branches and the second electrode stem.

Furthermore, a shape of each of the first intermediate portions and the second intermediate portions includes a triangle or a trapezoid.

Furthermore, the second lateral electrode stem includes a left electrode stem, a right electrode stem, and a second connection portion connecting the left electrode stem and the right electrode stem; the left electrode stem is bilaterally symmetrical with the right electrode stem; a part of the second electrode branches is connected to each other through the left electrode stem and one of the second longitudinal electrode stems, and the other part of the second electrode branches is connected to each other through the right electrode stem and the other second lateral electrode stem.

Furthermore, the touch electrode layer further including a buffer layer; an insulating layer disposed on the buffer layer; a first metal layer disposed in the insulating layer, wherein the first electrode chains are formed in the first metal layer; and a second metal layer disposed on the insulating layer, wherein the second electrode chains are formed in the second metal layer.

Furthermore, the touch electrode layer further including a buffer layer; an insulating layer disposed on the buffer layer and including a connection bridge corresponding to the crossing region; a first metal layer disposed on the insulating layer, wherein the first electrode chains are formed in the first metal layer; and a second metal layer disposed on the insulating layer and on a same layer as the first metal layer, wherein the second electrode chains are formed in the second metal layer, the first connection portion is the connection bridge in the crossing region, and the upper electrode stem and the lower electrode stem are electrically connected through the connection bridge.

Furthermore, the touch electrode unit includes a first center line defined along the first direction and a second center line defined along the second direction; the first electrode stem is bilaterally symmetric with respect to the first center line, and is up-down symmetric with respect to the second center line; and the second electrode stem is bilaterally symmetric with respect to the first center line, and is up-down symmetric with respect to the second center line.

Furthermore, an inclination angle of the first electrode branches is same as an inclination angle of the second electrode branches.

Furthermore, a third electrode is disposed between the first electrode and the second electrode, the third electrode is up-down symmetrical and has disconnected upper and lower two parts, and the third electrode is insulated from the first electrode and the second electrode.

Furthermore, each of the first electrode branches includes at least one electrode protrusion, the at least one electrode protrusion is perpendicular to the each of the first electrode branches; each of the second electrode branches includes at least one recess, and the at least one electrode protrusion is clamped in the at least one recess.

The invention also provides a touch display device including a substrate; a thin film transistor layer disposed on the substrate; a display layer disposed on the thin film transistor layer; the touch electrode layer described above, wherein the touch electrode layer is disposed on the display layer and connected to an integrated chip through a plurality of wires.

Furthermore, a thin film encapsulation layer is further disposed between the display layer and the touch electrode layer.

Beneficial Effect

The invention provides a touch electrode layer and a touch display device. The touch electrode layer has a first electrode and a second electrode. The first electrode has a first electrode stem and a plurality of first electrode branches arranged obliquely along the first electrode stem. The second electrode has a second electrode stem and a plurality of second electrode branches arranged obliquely along the second electrode stem. The first electrode and the second electrode are arranged in a symmetrical structure, and inclination angles of the first electrode branches and the second electrode branches are same. In a touch electrode unit, the shape and size of the first electrode and the second electrode are almost same, and the shape and size of the first electrode branches and the second electrode branches that are staggered are also almost the same. This can effectively improve a mutual capacitance value between a touch driving electrode and a touch sensing electrode, as well as make the distribution of a mutual capacitance electric field in an entire touch screen structure more uniform, which is more conducive to improve resolution and accuracy of a touch position detection.

The component reference numbers in the figures are as follows:

touch electrode unit100; first center line110; second center line120;

first electrode101; second electrode102; first longitudinal electrode stem1011;

first lateral electrode stem1012; first electrode branch1013; upper electrode stem1011a;

lower electrode stem1011b; first connection portion104; second longitudinal electrode stem1021;

second lateral electrode stem1022; second electrode branch1023; left electrode stem1022a;

right electrode stem1022b; second connection portion105; first electrode stem10;

thin film transistor layer302; display layer303;

first electrode chain11; and second electrode chain12.

DETAILED DESCRIPTION OF EMBODIMENTS

The following embodiments are referring to the accompanying drawings for exemplifying specific implementable embodiments of the present invention.

Embodiments of the present invention will be described in detail herein with reference to the drawings. The invention may take many different forms, and the invention should not be construed as merely the specific embodiments set forth herein. The embodiments of the present invention are provided to explain the practical application of the present invention, so that those skilled in the art can understand various embodiments of the present invention and various modifications suitable for a specific intended application.

First Embodiment

Shown inFIG.1is a touch electrode layer200according to a first embodiment of the present invention. In the first embodiment, the touch electrode layer200includes a plurality of first electrode chains11disposed along a first direction21. Each of the first electrode chains includes a plurality of first electrodes101electrically connected to each other. A plurality of second electrode chains12are disposed along a second direction22. Each of the second electrode chains includes a plurality of second electrodes102electrically connected to each other, and each of the first electrode chains11and each of the second electrode chains12are insulated from each other. The first direction21is perpendicular to the second direction22. The first electrode chain11is labeled with a vertical diamond-shaped dotted frame shown inFIG.1, and the second electrode chain12is labeled with a horizontal diamond-shaped dotted frame shown inFIG.1.

Each of the first electrodes101intersects with one of the second electrodes102corresponding to the first electrode to form a touch electrode unit100. In other words, the touch electrode units100are distributed in an array on an insulating layer202, and the touch electrode units100are connected to a driving chip through a plurality of wires.

As shown inFIG.2, each of the first electrodes101includes a first electrode stem10and a plurality of first electrode branches1013. Each of the first electrode branches1013is obliquely connected to the first electrode stem10.

Each of the second electrodes102includes a second electrode stem20and a plurality of second electrode branches1023. Each of the second electrode branches1023is obliquely connected to the second electrode stem20. Each of the first electrode branches1013and each of the second electrode branches1023are staggered and insulated from each other. Each of the first electrode branches1013is arranged in a gap between two adjacent second electrode branches1023.

The first electrode101is a driving electrode, as shown in the light-colored region in the figure; the second electrode102is a sensing electrode, as shown in the dark-colored region in the figure.

Material of the first electrode101and the second electrode102can be full-surface indium tin oxide; it can also be a hollow metal grid structure as in the present embodiment, and the material can be Ti, Al, Mo, Ag, Cu, and other metal materials, or alloys of the above-mentioned several metal materials.

The first electrode stem10includes a first longitudinal electrode stem1011and two first lateral electrode stems1012respectively positioned at two ends (ie, upper and lower ends) of the first longitudinal electrode stem1011.

The first longitudinal electrode stem1011is vertically connected to the two first lateral electrode stems1012, and the first longitudinal electrode stem1011is bilaterally symmetrical. As shown inFIG.1, the first longitudinal electrode stem1011is disposed along a first center line110and is bilaterally symmetric with respect to the first center line110.

The first longitudinal electrode stem1011includes an upper electrode stem1011a, a lower electrode stem1011b, and a first connection portion104. The first connection portion104connects the upper electrode stem1011aand the lower electrode stem1011b.

The upper electrode stem1011aand the lower electrode stem1011bare up-down symmetrical. Specifically, as shown inFIG.1, the upper electrode stem1011aand the lower electrode stem1011bare up-down symmetric with respect to a second center line120, and the second center line120is perpendicular to the first center line110.

The two first lateral electrode stems1012are up-down symmetric with respect to the second center line120and are parallel to the second center line120.

The first electrode branches1013are symmetrically distributed in the touch electrode unit100. Specifically, the first electrode branches1013are symmetrically distributed on both sides of the first longitudinal electrode stem1011, that is, the first electrode branches1013are bilaterally symmetric with respect to the first center line110, and are up-down symmetric with respect to the second center line120.

As shown inFIG.2, a part of the first electrode branches1013is connected to each other through the upper electrode stem1011aand one of the first lateral electrode stems1012, and the other part of the first electrode branches1013is connected to each other through the lower electrode stem1011band another one of the first lateral electrode stems1012. It can be seen that the two parts of the first electrode branches1013are not directly connected to each other. That is, part of the first electrode branches and the other part of the first electrode branches are not directly connected to each other. In other words, the first electrode branches1013which are symmetric with respect to the second center line120are not directly connected to each other, but are indirectly connected through the upper and lower electrode stems and the first connection portion. That is, the second center line120divides all the first electrode branches1013into two parts, upper part and lower part.

In other words, the first electrode branches1013are connected to the first longitudinal electrode stem1011or the first lateral electrode stem1012.

The first electrode branches1013connected to both sides of the first longitudinal electrode stem1011are symmetric with respect to the first center line110, and the first electrode branches1013connected to the first lateral electrode stem1012are also bilaterally symmetric with respect to the first center line110.

A plurality of first intermediate portions (reference numerals140and130) are disposed between the first electrode branches1013and the first electrode stem10, where reference numeral130is the first intermediate portion positioned between the first longitudinal electrode stem1011and the first electrode branches1013, and the reference numeral140is the first intermediate portion positioned between the first lateral electrode stem1012and the first electrode branches1013. A shape of the first intermediate portions is a right-angled triangle, and the hypotenuse of the right-angled triangle connects the first longitudinal electrode stem1011or the first lateral electrode stem1012. The first electrode branches1013are perpendicular to the first intermediate portions130or140, which are especially perpendicular to a right-angled edge of the first intermediate portion.

The second electrode stem20includes two second longitudinal electrode stems1021and a second lateral electrode stem1022positioned between the two second longitudinal electrode stems1021.

The two second longitudinal electrode stems1021are vertically connected to the second lateral electrode stem1022, and the second lateral electrode stem1022are disposed along the second center line120and are symmetric with respect to the first center line110.

The second lateral electrode stem1022includes a left electrode stem1022a, a right electrode stem1022b, and a second connection portion105. The second connection portion105connects the left electrode stem1022aand the right electrode stem1022b.

The left electrode stem1022aand the right electrode stem1022bare bilaterally symmetrical. Specifically, as shown inFIG.1, the left electrode stem1022aand the right electrode stem1022bare symmetric with respect to the first center line110.

The second electrode branches1023are symmetrically distributed in the touch electrode unit100. Specifically, the second electrode branches1023are symmetrically distributed on both sides (upper and lower sides) of the second lateral electrode stem1022, that is, the second electrode branches1023are up-down symmetric with respect to the second center line110, and the second electrode branches1023are bilaterally symmetrical along the first center line110.

As shown inFIG.2, a part of the second electrode branches1023is connected to each other through the left electrode stem1022aand one of the second longitudinal electrode stems1021, and the other part of the second electrode branches1023is connected to each other through the right electrode stem1022band the other second lateral electrode stem1022. The two parts of the second electrode branches1023are not directly connected to each other. That is, one part of the second electrode branches and the other part of the second electrode branches are not directly connected to each other. In other words, the second electrode branches1023that are symmetric with respect to the first center line110are not directly connected to each other, but are indirectly connected through the left and right electrode stems1022a,1022b, and the second connection portion105. That is, the first center line110divides all the second electrode branches1023into left and right parts.

In other words, the second electrode branches1023are connected to the second longitudinal electrode stem1021or the second lateral electrode stem1022.

A plurality of second intermediate portions (reference numerals150and160) are disposed between the second electrode branches1023and the second electrode stem20, where reference numeral150is the second intermediate portion positioned between the second lateral electrode stem1022and the second electrode branches1023, and reference numeral160is the second intermediate portion positioned between the second longitudinal electrode stem1021and the first electrode branches1023. A shape of the second intermediate portion is a right-angled triangle, and the hypotenuse of the right-angled triangle connects the second longitudinal electrode stem1021or the second lateral electrode stem1022. The second electrode branches1023are perpendicular to the second intermediate portion150or160, which are especially perpendicular to a right-angled edge of the second intermediate portion.

The first electrode branches1013are obliquely connected to the first electrode stem10, and the second electrode branches1023are obliquely connected to the second electrode stem20. An inclination angle of the first electrode branches1013is same as an inclination angle of the second electrode branches1023, for example, both range from 0 degree to 90 degrees.

More specifically, a part of the first electrode branches1013is obliquely connected to the first lateral electrode stem1012, and the other part of the first electrode branches1013is obliquely connected to the first longitudinal electrode stem1011. Similarly, a part of the second electrode branches1023is obliquely connected to the second lateral electrode stem1022, and the other part of the second electrode branches1023is obliquely connected to the second longitudinal electrode stem1021. The inclination angles of the first electrode branches1013and the second electrode branches1023are same, for example, both range from 0 degrees to 90 degrees. It can be seen that the first electrode branches1013and the second electrode branches1023are parallel to each other.

The first electrode101and the second electrode102are insulated from each other. The first lateral electrode stem1012intersects with the second longitudinal electrode stem1021to form a crossing region, and each of the first electrodes101and each of the second electrodes102are insulated from each other in the crossing region. Each of the first electrode branches1013is arranged in a gap between two adjacent second electrode branches1023.

Therefore, the above structural design can realize that the first electrode branches1013and the second electrode branches1023are coupled to each other, which can effectively improve the mutual capacitance value between the first electrode101and the second electrode102, and at the same time, make the mutual capacitance electric field line distribution more uniform, which is more conducive to improve the resolution and accuracy of detecting the touch position.

In this way, through the optimum coupling between driving electrode (TX)/sensing electrode (RX), a coupling area of adjacent Tx/Rx junctions is enlarged to increase a mutual capacitance signal change amount ΔCm when a touch is performed, thereby effectively improving the touch sensitivity.

As shown inFIG.3, the cross-sectional structure of the touch electrode layer200specifically includes a buffer layer201, an insulating layer202, a first metal layer23, and a second metal layer24.

The insulating layer202is disposed on the buffer layer201. The first electrode chains11are formed in the first metal layer23, and the second electrode chains12are formed in the second metal layer24. In the present embodiment, the first metal layer23and the second metal layer24are disposed on a same layer.

As shown inFIG.4, in the crossing region150, the first connection portion104is a connection bridge, which is defined in the insulating layer202and is used to connect the first electrode101. The second connection portion105and the second electrode102(as shown inFIG.1) are disposed on a same layer, and the first connection portion104and the second connection portion105are both metal wires.

In other embodiments, the first metal layer and the second metal layer can be disposed in different layers, thereby preventing cross-connection in the crossing region. In the crossing region, the first electrode101and the second electrode102can be directly connected and no connection bridge is required. Specifically, the first metal layer is disposed in the insulating layer, and the second metal layer is disposed above the insulating layer.

In an embodiment, the present invention does not limit the number and structure of the connection bridges. It adopts a double bridge structure, and the two connection bridges are independent and are not connected to each other.

The first embodiment provides a single layer of touch electrode200. The first electrode101and the second electrode102have the first electrode stem10and the second electrode stem20, respectively. The first electrode branches and the second electrode branches are obliquely disposed along the first electrode stem10and the second electrode stem20, respectively. The first electrodes101and the second electrodes are respectively symmetric with respect to the first center line and the second center line as the center axes, and the inclination angles of the electrode branches are same. In the touch electrode unit, the shape and size of the first electrode101and the second electrode102are almost same, and the shape and size of the electrode branches staggered adjacent to each other on the first electrode and the second electrode are also almost the same. This can effectively improve a mutual capacitance value between a touch driving electrode and a touch sensing electrode, as well as make the distribution of a mutual capacitance electric field in an entire touch screen structure more uniform, which is more conducive to improve resolution and accuracy of a touch position detection.

Second Embodiment

Shown inFIG.5is the touch electrode layer200aaccording to a second embodiment of the present invention. The difference between the second embodiment and the first embodiment is that the shape of the intermediate portion130apositioned between the first electrode branches1013aand the first electrode stem10ais a right-angled trapezoid, and a height of the right-angled trapezoid is perpendicular to the first electrode stem10a.

The shape of the second intermediate portion140apositioned between the second electrode branches1014aand the second electrode stem20ais also a right-angled trapezoid, and the height of the right-angled trapezoid is perpendicular to the second electrode stem20a.

Third Embodiment

Shown inFIG.6is the touch electrode layer200baccording to a third embodiment of the present invention. The difference between the third embodiment and the second embodiment is that each of the first electrode branches1013bhas at least one electrode protrusion1014b, and the at least one electrode protrusion1014bis perpendicular to the each of the first electrode branches1013b. Each of the second electrode branches1023bhas at least one recess1024b, and the at least one electrode protrusion1014bis clamped in the at least one recess1024b.

The electrode protrusion1014bcan further increase the coupling area of adjacent Tx/Rx junctions to increase the mutual capacitance signal change amount ΔCm when a touch is performed, thereby effectively improving touch sensitivity.

Fourth Embodiment

Shown inFIG.7is the touch electrode layer200caccording to a fourth embodiment of the present invention. The fourth embodiment differs from the first embodiment in that a third electrode103cis disposed between the first electrode101cand the second electrode102c. The third electrode103cis up-down symmetric with respect to the second center line120cand has disconnected upper and lower two parts. The third electrode103cis electrically insulated from the first electrode and the second electrode and is not connected to each other. Moreover, a grid structure constituting the third electrode103csurrounds at least one or more sub-pixels.

The fourth embodiment can effectively reduce the basic mutual capacitance value Cm, thereby improving the change rate of Cm when a touch is performed. The touch electrode unit according to the four embodiments of the present invention are not isolated, and different embodiments can be combined together to obtain better effects.

As shown inFIG.8, the present invention further provides a touch display device300including a substrate301, a thin film transistor layer302, a display layer303, an encapsulation layer304, the touch electrode layer200, a polarizer305, and a glass cover306.

A thin film transistor is a low temperature polysilicon transistor, the thin film transistor layer302is disposed on the substrate301, the display layer303is disposed on the thin film transistor layer302, and the encapsulation layer304is disposed on the display layer303.

The touch electrode layer200is disposed on the display layer303, and the touch electrode layer200is connected to an integrated chip through a plurality of wires203. The polarizer305is disposed on the touch electrode layer200, and the glass cover306is disposed on the polarizer305, and the glass cover306and the polarizer305are adhered to each other through an optical glue.

The glass cover306can be a transparent thin film, and the touch display device can be made into a folded display device.

A plurality of electrode grid lines of the touch electrode layer200are spaced from sub-pixels of the touch display device300, and electrode wirings should be defined between the sub-pixels.

The embodiment of the present invention provides the touch display device300having the touch electrode layer200. The touch electrode layer200has an array of touch electrode units100. Each of the touch electrode units100has the first electrode101and the second electrode102. The first electrode101and the second electrode102have the first electrode stem10and the second electrode stem20, respectively. The first electrode branches and the second electrode branches are obliquely disposed along the first electrode stem10and the second electrode stem20, respectively. The first electrodes101and the second electrodes are respectively symmetric with respect to the first center line and the second center line as the center axes, and the inclination angles of the electrode branches are same. In the touch electrode unit, the shape and size of the first electrode101and the second electrode102are almost same, the shape and size of the electrode branches staggered adjacent to each other on the first electrode and the second electrode are also almost the same. This can effectively improve the mutual capacitance value between the touch driving electrode and the touch sensing electrode, as well as make the distribution of the mutual capacitance electric field in an entire touch screen structure more uniform, which is more conducive to improve resolution and accuracy of a touch position detection.

Embodiments of the present application have been described, but not intending to impose any unduly constraint to the appended claims. For a person skilled in the art, any modification of equivalent structure or equivalent process made according to the disclosure and drawings of the present invention, or any application thereof, directly or indirectly, to other related fields of technique, is considered encompassed in the scope of protection defined by the claims of the present invention.

The technical scope of the present invention is not limited to the above description, a person skilled in the art can make various modifications and changes to the above embodiments without departing from the technical idea of the present invention, and such variations and modifications are intended to be within the scope of the invention.