Abstract:
Disclosed is a touch display apparatus including a display panel, a substrate and a touch-sensing layer thereon. The substrate is disposed above the display panel and includes a touch-sensing region and a non-touch-sensing region. The touch-sensing layer includes a first trace, and at least a part of the first trace is disposed above the non-touch-sensing region. A mesh pattern is formed on a surface of the first trace.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application claims priority of Taiwan Patent Application No. 104100366, filed on Jan. 7, 2015, the entirety of which is incorporated by reference herein. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The disclosure relates to a touch display apparatus, and in particular it relates to the surface of a trace in a touch display apparatus. 
         [0004]    2. Description of the Related Art 
         [0005]    A conventional touch-sensing device usually includes sensing electrodes and traces on a touch-sensing substrate, and the traces are electrically connected to the sensing electrodes. The traces can be electrically connected to a bonding pad set, and the bonding pad set can be further electrically connected to an external circuit such as a flexible circuit board. The current or signals can be delivered from the external circuit to the sensing electrodes through the bonding pad set and the traces, thereby driving the touch-sensing device. 
         [0006]    However, the conventional traces and protection layer formed thereon (and the touch-sensing substrate underlying the traces) have insufficient adhesion, thereby causing delamination or peeling problems. When the touch-sensing device is integrated with a display device to complete a touch display apparatus, the flat surface of the traces easily reflecting light to give the touch display apparatus has an uneven brightness. Accordingly, a novel standard for the traces for solving above problems is called for. 
       BRIEF SUMMARY 
       [0007]    One embodiment of the disclosure provides a touch display apparatus, comprising: a display panel; a first substrate disposed above the display panel, wherein the first substrate includes a touch-sensing region and a non-touch-sensing region; and a first touch-sensing layer disposed above the first substrate; wherein the first touch-sensing layer includes a first trace, a part of the first trace is disposed above the non-touch-sensing region, and a mesh pattern is formed on a surface of the first trace. 
         [0008]    A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The disclosure can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
           [0010]      FIG. 1  shows a top view of a touch-sensing device in one embodiment of the disclosure; 
           [0011]      FIG. 2  is an enlarged diagram of a trace in one embodiment of the disclosure; 
           [0012]      FIG. 3  shows a reflection pattern of the trace corresponding to an incident light; 
           [0013]      FIG. 4A  shows a touch display apparatus in one embodiment of the disclosure; 
           [0014]      FIG. 4B  shows a touch display apparatus in one embodiment of the disclosure; 
           [0015]      FIG. 5A  shows a reflection effect of the trace for a light from the display device in one embodiment of the disclosure; and 
           [0016]      FIG. 5B  shows a reflection effect of the trace for a light from the display device in one comparative embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    The following description is of the best-contemplated mode of carrying out the disclosure. This description is made for the purpose of illustrating the general principles of the disclosure and should not be taken in a limiting sense. The scope of the disclosure is best determined by reference to the appended claims. 
         [0018]      FIG. 1  shows a top view of a touch-sensing device  10  in one embodiment of the disclosure. As shown in  FIG. 1 , the touch-sensing device includes a touch-sensing layer on a substrate  11 , and the substrate is divided into a non-touch-sensing region  11 A and a touch-sensing region  11 B. The touch-sensing layer includes sensing electrodes  13  and traces  15 . The sensing electrodes  13  are disposed above the touch-sensing region  11 B. A part of the traces  15  is disposed above the non-touch-sensing region  11 A, and a part of the traces  15  is disposed above the touch-sensing region  11 B to overlap with the sensing electrodes  13 . In the embodiment, the non-touch-sensing region  11 A surrounds the touch-sensing region  11 B, and this embodiment is for illustration only but not for limiting the disclosure. Alternatively, the non-touch-sensing region  11 A can be located outside of the touch-sensing region  11 B but not surrounding the touch-sensing region  11 B. In one embodiment, the substrate  11  is a flexible polymer thin film such as polyethylene terephthalate (PET), polycarbonate (PC), or the like. Although the sensing electrodes  13  in following embodiments and drawings are shaped like a rhombus with the same area and connected by connecting electrodes, it should be understood that the sensing electrodes  13  can be another shape (e.g. triangle, tetragon, hexagon, or another possible shape) with the same or different areas if necessary. In one embodiment, the sensing electrodes  13  and the connecting electrodes therebetween can be made of a transparent conductive material (such as indium tin oxide (ITO) or indium zinc oxide (IZO)) formed by the following steps: depositing a transparent conductive layer, and patterning the transparent conductive layer by lithography and etching to define the sensing electrodes  13  and the connecting electrodes. 
         [0019]    In one embodiment, a terminal of one trace  15  is connected to the sensing electrode  13 , and an overlapping part of the terminal and the sensing electrode  13  is defined as a connection part  151 . Another terminal of the same trace  15  can be connected to a bonding pad (not shown). The bonding pad such as ITO or IZO can be formed overlying or underlying the traces  15 , such that the sensing electrode  13  can be electrically connected to an external circuit (not shown) through the traces  15  and the bonding pad (not shown). As such, the external circuit may drive the sensing electrode  13  and receive signals from the sensing electrode  13 . The traces  15  can be made of metal such as copper, aluminum, silver, another metal, or an alloy thereof. In one embodiment, the traces  15  can be formed by screen printing, thereby forming a mesh pattern on a surface of the traces  15 . Note that the method of forming the traces  15  (e.g. screen printing) is preferably performed on a flexible substrate  11  for forming the mesh pattern on the surface of the traces  15 . The mesh pattern on the surface of the traces  15  helps the adhesion between the traces  15  and other layers, thereby avoiding delamination or peeling problems. In addition, the mesh pattern may diffuse the light to prevent uneven brightness on images. 
         [0020]      FIG. 2  shows an enlarged diagram of the trace  15  in  FIG. 1 . In  FIG. 2 , the trace  15  has a mesh pattern on its surface. The mesh pattern includes protrusions  15 P and concaves  15 C, and the protrusions  15 P are disposed between the concaves  15 C. Although the concaves  15 C in  FIG. 2  are shaped like a rhombus, they may have other shapes such as circle, ellipse, or polygon such as square, rectangle, pentagon, hexagon, or another polygon. In one embodiment, the total surface of the concaves  15 C is greater than the total area of the protrusions  15 P, thereby enhancing the light diffusion effect and improving the uniformity of the brightness of the touch display apparatus. The total area of the concaves  15 C and the total surface of the traces  15  have a preferred ratio of 55:100 to 90:100, thereby causing a better uniformity of the light. 
         [0021]    In detail, the trace  15  includes a body part  155  extending along the length of the trace, a connection part  151  overlapping the sensing electrode  13 , and a neck part  153  connecting the body part  155  and the connection part  151 . The neck part  153  extends in a direction that is different from the direction of the length  155 L of the body part  155 . The connection part  151  has an edge  15 E, and the neck part  153  and the body part  155  have an edge  15 E′. In other words, the part of the trace  15  not overlapping the sensing electrode  13  has the edge  15 E′. The sensing electrode  13  has an edge  13 E. In one embodiment, the roughness of the edge  15 E′ is greater than the roughness of the edge  15 E, and the roughness of the edge  15 E is greater than the roughness of the edge  13 E. The roughness of the edge  15 E′ is greater than the roughness of the edge  15 E, thereby enhancing the adhesion between the trace  15  and other layers to avoid delamination or peeling, and further helping to diffuse the light and preventing the uneven brightness of the images. 
         [0022]    As shown in  FIG. 2 , the neck part  153  has a width  15 W in a direction parallel to the length direction  155 L of the trace  15 , and the connection part  151  has a width  15 W′ in a direction parallel to the length direction  155 L of the trace  15 . In one embodiment, the width  15 W′ is greater than the width  15 W. 
         [0023]    In one embodiment, the body part  155  of the trace  15  extends along the length direction  155 L, and the protrusions  15 P (or the concaves  15 C) of the mesh pattern are oriented in direction  21 B. In one embodiment, the length direction  155 L and direction  21 B are different to avoid a Moire effect caused by the mesh pattern and pixels of the underlying display device. Note that the mesh patterns of the two adjacent traces  15  are arranged in the same direction  21 B (not shown), such that the light has similar diffusion effect on each of the traces  15 . As such, the light can be effectively uniform. 
         [0024]    The touch-sensing device  10  can be integrated with a display device to complete the touch display apparatus. As such, the incident light from the display device exposes the traces  15  to produce a reflection pattern, as shown in  FIG. 3 . The reflection pattern is divided into bright regions  15 B and dark regions  15 D, and the bright regions  15 B are disposed between the dark regions  15 D. In one embodiment, the bright regions  15 B correspond to the protrusions  15 P of the traces  15 , and the dark regions  15 D correspond to the concaves  15 C. Similarly, the total area of the dark regions  15 D is greater than the total area of the bright regions  15 B, and the dark regions  15 D may have a shape other than the rhombus as shown in  FIG. 3 , such as circle, ellipse, or polygon (e.g. square, rectangle, pentagon, hexagon, or another polygon). 
         [0025]    As shown in  FIG. 4A , the touch-sensing device  10  can be collocated with another touch-sensing device  40 . In one embodiment, the touch-sensing device  40  may utilize the design of the touch-sensing device  10 , with the difference therebetween being the directions in which the sensing electrodes are arranged. For example, the sensing electrodes  13  of the touch-sensing device  40  are arranged in a direction vertical to (or across) the direction in which the sensing electrodes  13  of the touch-sensing device  10  are arranged. Alternatively, the design of the touch-sensing device  40  utilizes another design other than that of the touch-sensing device  10 . In another embodiment, the positions of the touch-sensing devices  10  and  40  are opposite to that in  FIG. 4A , in which the touch-sensing device  40  is disposed between the touch-sensing device  10  and a cover  42 . The touch-sensing devices  10  and  40  can be disposed between the display device  44  and the cover  42  to complete the touch display apparatus. A black matrix BM on the cover  42  corresponds to the traces  15  of the touch-sensing device  10 , and the black matrix BM is preferably disposed between the cover  42  and the touch-sensing device  10 . For example, the cover  42  can be a glass cover or a plastic cover with a light transmittance greater than 85%. In one embodiment, the display device  44  can be an electronic paper, an electronic reader, an electroluminescent display (ELD), an organic electroluminescent display (OELD), a vacuum fluorescent display (VFD), a light emitting diode display (LED), a cathode ray tube (CRT), a liquid crystal display (LCD), a plasma display panel (PDP), a digital light processing (DLP) display, a liquid crystal on silicon (LCoS), an organic light-emitting diode (OLED), a surface-conduction electron-emitter display (SED), a field emission display (FED), a quantum dot laser TV, a liquid crystal laser TV, a ferro liquid display (FLD), an interferometric modulator display (iMoD), a thick-film dielectric electroluminescent (TDEL), a quantum dot light emitting diode (QD-LED), a telescopic pixel display (TPD), an organic light-emitting transistor (OLET), an electrochromic display, a laser phosphor display (LPD), or the like. The display device  44  is preferably an electroluminescent display (ELD), an organic electroluminescent display (OELD), vacuum fluorescent display (VFD), light emitting diode display (LED), a cathode ray tube (CRT), a liquid crystal display (LCD), a plasma display panel (PDP), an organic light-emitting diode (OLED), a surface-conduction electron-emitter display (SED), a field emission display (FED), an organic light-emitting transistor (OLET), or a laser phosphor display (LPD). 
         [0026]    As shown in  FIG. 4B , another touch-sensing layer  46  is formed under the substrate  11  of the touch-sensing device  10 . The touch-sensing layer  46  may utilize the design of the touch-sensing layer of the touch-sensing device  10 , with the difference therebetween being the directions in which the sensing electrodes  13  are arranged. For example, the sensing electrodes  13  of the touch-sensing layer  46  are arranged in a direction vertical to (or across) the direction in which the sensing electrodes  13  of the touch-sensing device  10  are arranged. Alternatively, the design of the touch-sensing layer  46  utilizes another design other than the shape of the sensing electrodes  13  in the touch-sensing device  10 . In another embodiment, the positions of the touch-sensing layer  46  and the touch-sensing layer of the touch-sensing device  10  are opposite to that in  FIG. 4B , in which the touch-sensing layer  46  is disposed between the touch-sensing layer of the touch-sensing device  10  and the cover  42 . In addition, the touch-sensing layer  46  and the touch-sensing electrodes  13  are coplanar. In the embodiment, the display device  44  is similar to that in a previously described embodiment and the description thereof is omitted here. 
         [0027]      FIG. 5A  is illustrated on the basis of the touch display apparatus in  FIG. 4A , and it should be understood that the touch display apparatus in  FIG. 4B  has a similar phenomenon. While the light  51  L emitted by the display device  44  exposes the traces  15 , a part of the light may travel through the traces  15  and then be reflected by the surface of the traces to form the reflection light  51 R due to the thinness of the traces  15 . The reflection light  51 R may travel back to and then re-reflected by the surface of the display device  44 , thereby traveling through the substrate  11  and toward outside of the touch display apparatus. Because the mesh pattern is formed on the surface of the traces  15 , the reflection light  51 R will be a diffuse reflection other than focus on one point, thereby preventing the images from having uneven brightness. If the traces  15  have a flat surface other than the mesh pattern, the light  51 L exposing to the traces  15  will be reflected to produce a reflection light  51 R focused on one point. As such, the image will have uneven brightness as shown in  FIG. 5B . 
         [0028]    While the disclosure has been described by way of example and in terms of the preferred embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.