TW201917542A - Touch panel and method for making the same - Google Patents

Abstract

A touch panel includes a plurality of first electrodes and a plurality of second electrodes. The second electrodes are electrically insulated from the first electrodes. Each of the first electrodes includes a plurality of first electrode pads and a plurality of metal bridge structures. Each of the metal bridge structures connects two adjacent first electrode pads. Each metal bridge structure includes a first contact portion, a second contact portion and a first connecting portion. The touch panel further includes a substrate and an insulation layer. The metal bridge structures are disposed on the substrate, and the insulation layer is disposed on the metal bridge structures and the substrate. The insulation layer includes a first through hole and a second through hole. The second electrodes and the first electrode pads are disposed on the insulation layer. The two adjacent first electrode pads are respectively coupled the first contact portion and the second contact portion by the first through hole and the second through hole. Both the minimum width of the first contact portion and the minimum width of the second contact portion are greater than the minimum width of the first connecting portion.

Description

Touch screen and manufacturing method thereof

The invention relates to a touch screen and a method of manufacturing the same.

At present, touch screens have been widely used in display devices of various electronic products, so that the user can control the operation of the electronic products by using touch. In order to make the electrodes of the touch area difficult to be visually recognized, the indium tin oxide (ITO) is usually used to form the transparent touch electrode. The touch screen generally includes a first electrode extending in the first direction and extending in the second direction. And a second electrode that is insulated from the first electrode.

In a touch screen of a single-layer conductive layer (SITO) structure, the first electrode and the second electrode are disposed in the same layer, but are insulated at the intersection by an insulating layer, wherein the second The two portions of the electrode on both sides of the first electrode may be connected by a through hole of the insulating layer or by a metal bridge. However, whether the through hole of the insulating layer or the metal bridge is overlapped, it is generally required to pass twice. The mask performs a process of alignment exposure (such as one-time exposure of the insulating layer and one-time exposure of the metal bridge) to realize electrical connection of the two portions of the second electrode, but two alignment exposures This results in a large cumulative tolerance or a misalignment, which tends to cause poor connection of the two portions of the second electrode, reducing the yield of the touch screen.

In view of the above, it is necessary to provide a touch panel and a method of manufacturing the same that can improve the above-described connection failure and yield problems.

A touch screen including a first electrode extending in a first direction, and a second electrode extending in a second direction different from the first direction and insulated from the first electrode, the first electrode including a plurality of first electrode portions and a metal bridge structure connected between the adjacent two first electrode portions, the second electrode is insulatively overlapped with the metal bridge structure, and the metal bridge structure includes a first contact portion a second contact portion and a first connection portion connected between the first contact portion and the second contact portion, the touch screen further includes a substrate and an insulating layer, and the metal bridge structure is disposed on the substrate The insulating layer is disposed on the metal bridge structure and the substrate, and the insulating layer includes a first through hole corresponding to the first contact portion and a second through hole corresponding to the second contact portion. The second electrode and the plurality of first electrode portions are disposed on the insulating layer, and a first electrode portion of the two adjacent first electrode portions corresponds to the first through hole and a first through hole connecting the first contact portion, The other first electrode portion of the two adjacent first electrode portions corresponds to the second through hole, and the second contact portion is connected by the second through hole, and the minimum width of the first contact portion is The minimum width of the second contact portion is greater than the minimum width of the first connecting portion.

In one embodiment, the insulating layer is a negative photoresist material.

In one embodiment, the minimum width of the first contact portion and the minimum width of the second contact portion are both greater than twice the minimum width of the first connection portion.

In an embodiment, the first contact portion and the second contact portion have a shape of a rectangle, a circle, an ellipse, a diamond, a polygon, or an irregular shape.

In one embodiment, the first connecting portion includes at least one strip portion connected between the first contact portion and the second contact portion.

In one embodiment, the first connecting portion includes a plurality of strip portions, and the plurality of strip portions are alternately formed into a lattice line.

In one embodiment, the at least one shaped portion is a straight strip, a wavy strip or a zigzag strip.

In one embodiment, the width of the strip portion is less than or equal to 20 μm, and the minimum width of the first contact portion and the second contact portion is less than or equal to 50 μm.

In one embodiment, the touch screen further includes a peripheral trace disposed on the substrate, the peripheral trace and the metal bridge structure are formed in the same mask process, and each peripheral trace is connected to the first An electrode or a second electrode, each of the peripheral traces includes a contact pad and a trace portion, the contact pad connecting the corresponding first or second electrode by a third via located in the insulating layer The wire portion is configured to connect an external circuit, and a minimum width of the contact pad is greater than a minimum width of the first connecting portion and a minimum width of the wire portion.

In one embodiment, the minimum width of the contact pads is greater than twice the minimum width of the first connection portion and the minimum width of the trace portion.

In one embodiment, an overlapping area of the first through hole and the first contact portion is greater than or equal to 90%, and an overlapping area of the second through hole and the second contact portion is greater than or equal to 90%, The overlapping area of the third through hole and the contact pad is greater than or equal to 90%.

A method of manufacturing the above touch screen, comprising the steps of:

Providing the substrate;

Forming the metal bridge structure on the substrate;

Forming the insulating layer on the substrate and the metal bridge structure, the insulating layer being a negative photoresist material;

Exposing and developing the insulating layer on the side of the substrate away from the metal bridge structure with the metal bridge structure as a mask, thereby forming the first through hole and the first layer in the insulating layer Two through holes; and

The plurality of first electrode portions and the second electrode are formed on the insulating layer.

Compared with the prior art, in the touch screen and the manufacturing method of the present invention, the minimum width of the first contact portion and the second contact portion of the metal bridge structure are greater than the minimum width of the first connection portion, and negative light can be used. And exposing and developing the insulating layer by using the metal bridge structure as a mask, wherein a minimum width of the first contact portion and the second contact portion is greater than a minimum width of the first connecting portion, The insulating layer at the position of the first connecting portion remains, but the insulating layer at the position of the first contact portion and the second contact portion is removed, thereby forming the first through hole and the second in the insulating layer Through-holes, the manufacturing method of the touch screen of the present invention can reduce a mask process, which simplifies the manufacturing method, and can be used in comparison with the conventional manufacturing method in which two masks are generally used to realize the connection of the two portions of the electrodes. Improve the connection failure caused by the two alignment exposures and reduce the yield of the touch screen.

1 and FIG. 2, FIG. 1 is a schematic plan view of a touch screen 10 according to a preferred embodiment of the present invention, and FIG. 2 is a cross-sectional view along line II-II of FIG. The touch screen 10 includes a substrate 11 , a first electrode 12 , a second electrode 13 , a peripheral trace 14 , and an insulating layer 15 .

The substrate 11 may be a transparent substrate, and the material thereof may be one of glass, sapphire, transparent resin (such as PET material), transparent ceramic, but is not limited to the above materials.

The first electrode 12 extends in a first direction X. The first electrode 12 includes a plurality of first electrode portions 121 and a metal bridge structure 122 connected between the adjacent two first electrode portions 121. The second electrode 13 extends in a second direction Y different from the first direction X and is insulated from the first electrode 12 by the insulating layer 15 . Specifically, the second electrode 12 is insulatively overlapped with the metal bridge structure 122.

The first electrode portion 121 and the second electrode 13 may both be transparent conductive materials (such as indium tin oxide material). Specifically, the first electrode portion 121 and the second electrode 13 may be in the same layer. Formed in the same mask process.

Further, the shape of the first electrode portion 121 may be a diamond shape, a circular shape, or the like, but is not limited to the above shape. The second electrode 13 may include a plurality of second electrode portions 131 arranged along the second direction Y and a second connecting portion 132 connected between the adjacent two second electrode portions 131, the second The shape of the electrode portion 131 may be a rhombus shape, a circular shape, or the like, but is not limited to the above shape. The second connecting portion 132 may have a strip shape, such as a straight strip shape, and may have a width smaller than a width of the second electrode portion 131. The second connecting portion 132 is insulatively overlapped with the metal bridging structure 122.

It can be understood that the number of the first electrodes 12 may be plural, the plurality of first electrodes 12 are spaced apart and each extend along the first direction X, and the spacing of any two adjacent first electrodes 12 may be All are equal. The number of the second electrodes 13 may be plural, and the plurality of second electrodes 13 are spaced apart and both extend along the second direction Y and the plurality of first electrodes 12 are in the metal bridge structure 122 Intersecting with the second connecting portion 132, the spacing of any two adjacent second electrodes 13 may be equal.

Please refer to FIG. 3. FIG. 3 is a schematic structural view of the metal bridge structure 122 shown in FIG. The metal bridge structure 122 may be disposed on the substrate 11 , and may include a first contact portion 123 connecting one first electrode portion 121 , a second contact portion 124 connecting another first electrode portion 121 , and a connection a first connecting portion 125 between the first contact portion 123 and the second contact portion 124. The minimum width of the first contact portion 123 and the minimum width of the second contact portion 124 are both greater than the minimum width of the first connecting portion 125. Preferably, the minimum width of the first contact portion 123 and the minimum width of the second contact portion 124 are both greater than twice the minimum width of the first connecting portion 125. The material of the metal bridging structure 122 may be an opaque metal material, such as a metal material having a lower impedance such as silver, copper or aluminum.

The shape of the first contact portion 123 and the second contact portion 124 is a rectangle, a circle, an ellipse, a diamond, a polygon, or an irregular shape. The first connecting portion 125 includes at least one strip portion connected between the first contact portion 123 and the second contact portion 124. The first contact portion 123 and the second contact portion 124 may be substantially the same in shape, so that the minimum width of the first contact portion 123 is equal to the minimum width of the second contact portion 124.

In this embodiment, the first contact portion 123 and the second contact portion 124 have a rectangular shape, such as a square shape, and the strip portion is a straight strip type, and the strip portion of the first connecting portion 125 The width may be less than or equal to 20 μm, and the minimum width of the first contact portion 123 and the second contact portion 124 (ie, the side length of the square) may be 50 μm or less.

It can be understood that, in the first modified embodiment, as shown in FIG. 4, the first contact portion 123 and the second contact portion 124 have a rectangular shape, such as a square, and the strip of the first connecting portion 125. The shape of the strip may be wavy, the width of the strip of the first connecting portion 125 may be less than or equal to 20 μm, and the minimum width of the first contact portion 123 and the second contact portion 124 (ie, the square Side length) can be less than or equal to 50 μm.

It can be understood that, in the second modified embodiment, as shown in FIG. 5, the shape of the first contact portion 123 and the second contact portion 124 is circular, and the strip portion of the first connecting portion 125 The width of the strip portion of the first connecting portion 125 may be less than or equal to 20 μm, and the minimum width of the first contact portion 123 and the second contact portion 124 (ie, the diameter of the circle) ) can be less than or equal to 50 μm.

It can be understood that, in the third modified embodiment, as shown in FIG. 6 , the shape of the first contact portion 123 and the second contact portion 124 is circular, and the strip portion of the first connecting portion 125 There may be a zigzag strip shape, and the number of strip portions of the first connecting portion 125 is plural, and the plurality of strip portions are alternately formed into a lattice line. The width of each strip portion may be less than or equal to 20 μm, and the minimum width of the first contact portion 123 and the second contact portion 124 (ie, the diameter of the circle) may be 50 μm or less.

The peripheral traces 14 are used to connect the first electrode 12 and the second electrode 13 to an external circuit (such as an external circuit connected by a flexible circuit board). Specifically, the peripheral trace 14 may be disposed on the On the substrate, the peripheral traces 14 can be formed in the same mask process as the metal bridge structure 122. Each of the peripheral traces 14 is connected to a first electrode 12 or a second electrode 13 . The trace 14 includes a contact pad 141 for connecting the corresponding first electrode or the second electrode, and a trace portion 142 for connecting an external circuit, the contact pad 141 The minimum width is greater than the minimum width of the first connecting portion 125 and the minimum width of the routing portion 142. Preferably, the minimum width of the contact pads 141 is greater than twice the minimum width of the first connecting portion 125 and the minimum width of the routing portion 142.

Further, a minimum width of the contact pad 141 may be equal to a minimum width of the first contact portion 123, and a minimum width of the routing portion 142 may be equal to a minimum width of the first connecting portion 125. In one embodiment, the width of the trace portion 142 may be less than or equal to 20 μm, and the minimum width of the contact pad 141 may be less than or equal to 50 μm.

The insulating layer 15 is disposed on the metal bridge structure 122, the peripheral traces 14, and the substrate 11. The insulating layer 15 includes a first through hole 151 corresponding to the first contact portion 123, and corresponds to a second through hole 152 of the second contact portion 124 and a third through hole 153 corresponding to the contact pad 141. The insulating layer 15 is a transparent insulating material. In the embodiment, the insulating layer 15 is a negative photoresist material, such as a polyisoprene rubber material.

It can be understood that the insulating layer 15 may not cover a portion of the peripheral trace 14 away from the end of the contact pad 141, thereby moving the peripheral trace 14 away from the end of the contact pad 141. The wire portion 142 is exposed to facilitate connection of components such as a flexible circuit board.

The second electrode 13 and the plurality of first electrode portions 121 are disposed on the insulating layer 15. One first electrode portion 121 of the two adjacent first electrode portions 121 corresponds to the first pass The first contact portion 123 is connected to the hole 151, and the other first electrode portion 121 of the two adjacent first electrode portions 121 is corresponding to the second through hole 152. The second contact portion 124 is connected to the second contact portion 124. The first electrode 12 and one end of the second electrode 13 are connected to the corresponding one of the peripheral traces 14 by the third through hole 153. Contact pad 141. In an embodiment, the overlapping area of the first through hole 151 and the first contact portion 123 may be greater than or equal to 90%, and the overlapping area of the second through hole 152 and the second contact portion 124 may be larger. The overlap area of the third through hole 153 and the contact pad 141 may be 90% or more.

Please refer to FIG. 7. FIG. 7 is a flow chart of a method of manufacturing the touch screen 10 of the present invention. The manufacturing method of the touch screen 10 includes the following steps S1-S5.

In step S1, a substrate is provided.

The specific structure of the substrate 11 has been described above and will not be described herein.

In step S2, a metal bridge structure and peripheral traces are formed on the substrate.

The specific structure of the metal bridge structure 122 and the peripheral traces 14 has been described above and will not be described herein. The step S2 may include the following steps:

Forming a metal material layer on the substrate 11;

Forming a first photoresist layer on the metal material layer;

Exposing and developing the first photoresist layer with a predetermined mask pattern to etch the metal material layer to form the metal bridge structure 122;

The first photoresist layer is removed.

Step S3, forming an insulating layer on the substrate, the metal bridge structure and the peripheral trace, the insulating layer being a negative photoresist material.

Step S4, exposing and developing the insulating layer on the side of the substrate away from the metal bridge structure and the peripheral trace with the metal bridge structure and the peripheral trace as a mask, thereby being in the insulating layer Forming a first through hole, a second through hole, and a third through hole.

In step S5, a plurality of first electrode portions and second electrodes are formed on the insulating layer.

The step S5 may include the following steps:

Forming a transparent conductive material layer on the insulating layer 15, the first through hole 151, the second through hole 152, and the third through hole 153;

Forming a second photoresist layer on the transparent conductive material layer;

Exposing and developing the second photoresist layer with a predetermined mask pattern to etch the transparent conductive material layer to form the first electrode portion 121 and the second electrode 13;

The second photoresist layer is removed.

It can be understood that the specific structural features of the first electrode portion 121 and the second electrode 13 have been previously described, and are not described herein again.

In the touch screen 10 and the manufacturing method of the present invention, the minimum widths of the first contact portion 123 and the second contact portion 124 of the metal bridge structure 122 are both greater than the minimum width of the first connecting portion 125. The minimum width of the contact pad 141 is greater than the minimum width of the first connecting portion 125 and the minimum width of the routing portion 142. A negative photoresist material may be used to the metal bridge structure 122 and the peripheral trace 14 Exposing and developing the insulating layer 15 for a mask, wherein a minimum width of the first contact portion 123 and the second contact portion 124 is greater than a minimum width of the first connecting portion 125, the contact pad 141 The minimum width is greater than the minimum width of the first connecting portion 125 and the minimum width of the routing portion 142, and the insulating layer 15 at the position of the first connecting portion 125 and the routing portion 142 may be retained, but the The first contact portion 123, the second contact portion 124, and the insulating layer 15 at the position of the contact pad 141 are removed, thereby forming the first through hole 151 and the second through hole 152 in the insulating layer 15. The third through hole 153 is generally adopted as compared with the prior art. The manufacturing method of the touch screen 10 of the present invention can reduce a mask process, which not only simplifies the manufacturing method, but also improves the connection failure caused by the two alignment exposures. And reducing the yield of the touch screen and the like.

Further, please refer to FIG. 8. FIG. 8 is a schematic diagram showing the comparison between the structure of the electrodes 12, 13 of the touch screen 10 and the peripheral traces 14 obtained by the manufacturing method of the touch screen 10 of the present invention and a known structure. As shown in FIG. 8(a), in a known structure, in order to make the contact pad 241 of the peripheral trace 24 and the first electrode 22 or the second electrode 23 accurately connected to the bit, The width of the contact pad 241 of the peripheral trace 24 generally needs to be designed to be wide to avoid the misalignment of the contact pad 241 and the corresponding electrode 22 or 23 cannot be contacted. Therefore, the border area of the peripheral trace 24 is also Need to be wider. However, as shown in FIG. 8(b), in the touch panel and the manufacturing method of the present invention, since the third via hole 153 in the insulating layer 15 is a mask of the contact pad 141 of the peripheral trace 14 The insulating layer 15 of the negative photoresist material is formed by reverse exposure, so that the contact pads 141 can be aligned with the first electrode 12 or the second electrode 13 more accurately, so that the width of the contact pad 141 It can be designed to be narrower, and thus the border area of the peripheral trace 14 is narrow.

Furthermore, please refer to FIG. 9. FIG. 9 is a diagram showing the parameter values of the line width dimension and the corresponding experimental test values of the peripheral trace 14 and the metal bridge structure 122 by using the manufacturing method of the touch panel 10 of the present invention. Specifically, the minimum width of the routing portion 142 of the peripheral trace 14 and the first connecting portion 125 may be sequentially designed to be 10-80 μm (as shown in FIG. 9( a )), such as a formation. The width of the corresponding pattern of the trace portion 142 and the first mask of the first connection portion 125 is sequentially 10-80 μm. Further, the width of the wiring portion 142 and the first connecting portion 125 is obtained by the first mask process as shown in the second column of the table shown in FIG. 9(b), wherein N/A represents that the line width is too narrow to form or measure an effective width, and the width of the third through hole 153 is obtained by a reverse exposure process as shown in the table of FIG. 9(b). As shown in the column, the actual width of the first contact portion 123 and the second contact portion 124 is as shown in the fourth column of the table shown in FIG. 9(b), the first through hole 152 and The actual width of the second through hole 153 is as shown in the fifth column of the table shown in (b) of FIG.

According to the table shown in FIG. 9(b), the minimum width design value of the routing portion 142 of the peripheral trace 14 and the first connecting portion 125 should be not less than 40 μm, thereby ensuring manufacturing by the above. The first contact portion 123, the second contact portion 124, the first through hole 151, the second through hole 152, and the third through hole 153 may each form or measure an effective width.

In addition, it can be understood that the minimum widths of the first through hole 151, the second through hole 152, and the third through hole 153 formed by different negative photoresist materials, different reverse exposure strengths or exposure angles may be different, actually In the application process, the contact pad 141, the trace portion 142, the first contact portion 123, the second contact portion 124, and the above may be designed according to different negative photoresist materials, different reverse exposure strengths or exposure angles. The minimum width of the first connecting portion 125 is used to obtain the touch screen 10 of the present invention, which will not be described herein.

Of course, the present invention is not limited to the above-disclosed embodiments, and the present invention may be variously modified in the above embodiments. Those skilled in the art will appreciate that appropriate changes and modifications of the above embodiments are within the scope of the invention as claimed.

10‧‧‧ touch screen

11‧‧‧Substrate

12‧‧‧First electrode

13‧‧‧second electrode

14‧‧‧around wiring

15‧‧‧Insulation

121‧‧‧First electrode section

122‧‧‧Metal bridging structure

X‧‧‧ first direction

Y‧‧‧second direction

131‧‧‧Second electrode section

132‧‧‧Second connection

123‧‧‧First contact

124‧‧‧Second contact

125‧‧‧First connection

141‧‧‧Contact pads

142‧‧‧Line Department

151‧‧‧ first through hole

152‧‧‧Second through hole

153‧‧‧ third through hole

S1-S5‧‧‧ steps

FIG. 1 is a schematic diagram showing the planar structure of a touch screen according to a preferred embodiment of the present invention.

Figure 2 is a cross-sectional view of Figure 1 taken along line II-II.

3 is a schematic structural view of the metal bridge structure shown in FIG. 1.

4, 5 and 6 are schematic structural views of metal bridge structures of several modified embodiments.

7 is a flow chart of a method of manufacturing a touch screen of the present invention.

FIG. 8 is a schematic diagram showing the comparison between the structure of the electrode of the touch screen and the peripheral trace connection obtained by the method for manufacturing the touch screen of the present invention and a known structure.

FIG. 9 is a diagram showing the parameter values of the line width and the corresponding experimental test values of the peripheral trace and the metal bridge structure by using the manufacturing method of the touch screen of the present invention.

Claims (12)

A touch screen comprising a first electrode extending in a first direction, and a second electrode extending in a second direction different from the first direction and insulated from the first electrode, the improvement being: The first electrode includes a plurality of first electrode portions and a metal bridge structure connected between the adjacent two first electrode portions, the second electrodes are insulated from the metal bridge structure, and the metal bridges The structure includes a first contact portion, a second contact portion, and a first connection portion connected between the first contact portion and the second contact portion, the touch screen further includes a substrate and an insulating layer, the metal bridge structure The insulating layer is disposed on the metal bridge structure and the substrate, and the insulating layer includes a first through hole corresponding to the first contact portion and a corresponding second contact portion a second through hole, the second electrode and the plurality of first electrode portions are disposed on the insulating layer, and a first electrode portion of the two adjacent first electrode portions corresponds to the first pass Hole and by the first through hole Connecting the first contact portion, the other first electrode portion of the two adjacent first electrode portions corresponding to the second through hole is connected to the second contact portion by the second through hole, The minimum width of the first contact portion and the minimum width of the second contact portion are both greater than the minimum width of the first connecting portion. The touch screen of claim 1, wherein: the insulating layer is a negative photoresist material. The touch screen of claim 1, wherein: the minimum width of the first contact portion and the minimum width of the second contact portion are both greater than twice the minimum width of the first connection portion. The touch screen of claim 1, wherein: the shape of the first contact portion and the second contact portion is a rectangle, a circle, an ellipse, a diamond, a polygon, or an irregular shape. The touch screen of claim 1, wherein: the first connecting portion includes at least one shaped portion, and the at least one shaped portion is connected between the first contact portion and the second contact portion. The touch screen of claim 5, wherein: the first connecting portion comprises a plurality of strip portions, and the plurality of strip portions are staggered to form a grid line. The touch screen of claim 5, wherein the at least one shaped portion is a straight strip shape, a wavy strip shape or a zigzag strip shape. The touch screen according to any one of claims 5 to 7, wherein the width of the strip portion is less than or equal to 20 μm, and the minimum width of the first contact portion and the second contact portion is less than or equal to 50 μm. The touch screen of claim 1, wherein the touch screen further comprises a peripheral trace disposed on the substrate, the peripheral trace and the metal bridge structure are formed in the same mask process, and each perimeter is Correspondingly connecting a first electrode or a second electrode, each of the peripheral traces includes a contact pad and a trace portion, wherein the contact pad is connected to the corresponding first by a third via hole located in the insulating layer An electrode or a second electrode, the wire portion is for connecting an external circuit, and a minimum width of the contact pad is greater than a minimum width of the first connecting portion and a minimum width of the wire portion. The touch screen of claim 9, wherein: the minimum width of the contact pads is greater than twice the minimum width of the first connecting portion and the minimum width of the routing portion. The touch screen of claim 9, wherein: the overlapping area of the first through hole and the first contact portion is greater than or equal to 90%, and the overlapping area of the second through hole and the second contact portion is greater than or equal to 90%, the overlapping area of the third through hole and the contact pad is greater than or equal to 90%. A method of manufacturing a touch panel according to claim 1, comprising the steps of: providing the substrate; forming the metal bridge structure on the substrate; forming the insulation on the substrate and the metal bridge structure a layer, the insulating layer is a negative photoresist material; exposing and developing the insulating layer on the side of the substrate away from the metal bridge structure with the metal bridge structure as a mask, thereby Forming the first via hole and the second via hole in the layer; and forming the plurality of first electrode portions and the second electrode on the insulating layer.