1. Technical Field
The invention relates to a touch panel.
2. Related Art
Many kinds of touch input technologies have been widely applied to electronic products. For example, the mobile phone and tablet computer both use a touch panel as an input interface. This kind of input interface provides the user an intuitive operation, so the user can directly contact the surface of the touch panel by a finger or stylus to give instructions, or move on the surface of the touch panel to select or operate the desired object or input characters.
A conventional touch panel includes at least a substrate and a conductive pattern, circuit layer, insulating layer and flexible printed circuit board (FPCB) pattern formed on the substrate. Generally, the conductive pattern is made by indium tin oxide (ITO) that is transparent and electrically conductive. However, when the size of the touch panel is getting larger, the area of the ITO on the substrate also increases and the surface resistance of the conductive pattern formed by ITO will rises a lot accordingly, so that the signal transmitted through the conductive pattern will be attenuated considerably. Therefore, a rear-end signal processor can not rapidly and precisely determine the position of the touch input, and the signal can't be processed and manipulated correctly.
Accordingly, the design of metal mesh is currently presented to replace the conventional ITO material of the touch panel so that the signal attenuation resulted from the large-area ITO can be avoided by using the metal material with its electrical conductivity. Besides, the metal material, in comparison with the ITO, has better flexibility so as to be applied to the flexible touch panel. However, due to the opaque property of the metal material, the aperture ratio will be decreased. Hence, for avoiding the decrement of the aperture ratio, the circuit of the metal mesh is made thinner and thinner. But, when the metal mesh is made by using the lithography etching technique, the metal mesh is often broken at the intersection due to the excessive etching.
Therefore, it is an important subject to provide a metal mesh touch panel that can reduce the signal attenuation during the transmission and can thus determine the touch input position precisely and rapidly without the problem of wire disconnection.
In view of the foregoing subject, an objective of the invention is to provide a touch panel that can reduce the signal attenuation during the transmission and can thus determine the touch input position precisely and rapidly.
To achieve the above objective, a touch panel according to the invention comprises a substrate and a conductive mesh pattern. The conductive mesh pattern is disposed on the substrate and comprises a wire area. The wire area has a plurality of wires. The wires intersect along a first direction and a second direction to form a plurality of intersections, a side of each of the intersections is extended to form a protrusion, and the intersection and the protrusion form a conductive connecting region. For the section of the same direction, a width of the conductive connecting region is greater than a width of the wire, and the normal vector of the section is substantially parallel to the extending direction of the wire.
To achieve the above objective, a touch panel according to the invention comprises a substrate and a conductive mesh pattern. The conductive mesh pattern is disposed on the substrate and comprises a wire area. The wire area has a plurality of wires. The wires intersect along a first direction and a second direction to form a plurality of intersections, a side of each of the intersections is extended to form a protrusion, and the intersection and the protrusion form a conductive connecting region. The conductive connecting region has a lower surface near the substrate, an upper surface opposite to the lower surface, and a side surface connecting the upper and lower surfaces, the upper surface has a first roughness, the side surface has a second roughness, the first roughness is greater than the second roughness, the first roughness is denoted by the height difference between the highest and lowest points of the upper surface within a unit length, and the second roughness is denoted by the height difference between the highest and lowest points of the side surface within a unit length.
To achieve the above objective, a touch panel according to the invention comprises a substrate and a conductive mesh pattern. The conductive mesh pattern is disposed on the substrate and comprises a wire area. The wire area has a plurality of wires. The wires intersect along a first direction and a second direction to form a plurality of intersections, a side of each of the intersections is extended to form a protrusion, and the intersection and the protrusion form a conductive connecting region. The conductive connecting region has a lower surface near the substrate, an upper surface opposite to the lower surface, and a side surface connecting the upper and lower surfaces, for a section of the conductive connecting region, a width of the upper surface is a first wire width, a width of the lower surface is a second wire width, a third wire width is between the upper surface and the lower surface, and the third wire width is less than the first wire width and less than the second wire width.
The invention will become more fully understood from the detailed description and accompanying drawings, which are given for illustration only, and thus are not limitative of the present invention, and wherein:
The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
The conductive mesh pattern 12 is disposed on the substrate 11 and has electrical conductivity. In this embodiment, the conductive mesh pattern 12 is made by metal, such as copper. For example, a copper film is formed on the substrate 11 by sputtering or evaporation, and then the processes of exposure, development and etching are implemented to form the conductive mesh pattern 12. To be noted, in other embodiments, the conductive mesh pattern 12 can be made by other kinds of metal or graphene and can be formed on the substrate 11 by other kinds of processes. In this embodiment, the conductive mesh pattern 12 is formed into a single-layer conductive pattern by implementing the lithography etching process to a single-layer metal, and has the thickness of 0.01 μm˜20 μm. Considering the requirement and design of the product and the difference of the adopted process, the thickness of the conductive mesh pattern 12 is favorably 0.1 μm˜10 μm or 0.2 μm˜10 μm.
The conductive mesh pattern 12 includes a wire area 121, which includes a plurality of first wires 122 and a plurality of second wires 123. The first wires 122 are disposed side by side on the surface of the substrate 11 along a first direction D1, and each of the first wires 122 is extended along a second direction D2. The second wires 123 are disposed side by side on the surface of the substrate 11 along the second direction D2, and each of the second wires 123 is extended along the first direction D1. As an embodiment, the first wire 122 can be extended along Y-axis direction while the second wire 123 is extended along X-axis direction. Otherwise, the first wire 122 is extended along X-axis direction while the second wire 123 is extended along Y-axis direction, or the first wire 122 is extended along the direction of 45° from Y-axis direction while the second wire 123 is extended along the direction of 45° from X-axis direction. However, the invention is not limited thereto. The first wires 122 and the second wires 123 intersect to form a plurality of intersections 124, and a side of each of the intersections 124 is extended to form a protrusion 125. The intersection 124 and the protrusion 125 form a conductive connecting region 126.
Besides, in the different embodiments, the width of the first section of the conductive connecting region 126 can be 2.5˜5 times the width of the first section of the first wire 122, or the width of the second section of the conductive connecting region 126 can be 2.5˜5 times the width of the second section of the second wire 123, or the width of the first section of the conductive connecting region 126 can be 3˜4 times the width of the first section of the first wire 122, or the width of the second section of the conductive connecting region 126 can be 3˜4 times the width of the second section of the second wire 123.
In this embodiment, by the first wire 122, the second wire 123, the intersection 124 and the protrusion 125 forming the conductive connecting region 126, the conductive mesh pattern 12 made by the electrically conducive material not only can effectively reduce the whole impedance but also can reduce the signal attenuation during the transmission, and also can effectively replace the ITO, and therefore the manufacturing cost can be reduced and the shortage of inflexibility of the ITO can be overcome. Furthermore, the problem of the wire disconnection at the wire intersection due to the excessive etching can be avoided. Besides, the first and second wires 122 and 123 are capable of transmitting the signal of higher current, and the impedance matching can be improved.
To be noted, as shown in
According to the entire circuit layout, the requirement of the product or the adopted process, the conductive connecting regions 126 of the same conductive mesh pattern 12 of the touch panel can have different embodiments. For example, some of the conductive connecting regions 126 can be embodied as shown in
As shown in
In this embodiment, the first roughness R1 of the upper surface S1 and the second roughness R2 of the side surface S2 of the conductive connecting region 126 are observed and measured by using a focus ion beam (FIB) microscope having a magnification of 5000ט50000×, and the measuring result is that the roughness R1 is less than or equal to 500 nm and the roughness R2 is less than or equal to 100 nm. In other embodiments, the roughness R1 is measured as less than or equal to 300 nm, or less than or equal to 200 nm. Besides, as shown in
To be noted, in this embodiment, the upper surface S1 of the conductive connecting region 126 is an uneven surface, so the adhesion of the anti-reflection layer (e.g. black layer) or protection layer (formed later) to the conductive connecting region 126 can be enhanced and the undesired reflection due to the smooth upper surface S1 can be avoided.
In addition to using the above-mentioned FIB microscope, the first roughness R1 and the second roughness R2 of the conductive connecting region 126 in other embodiments also can be measured by the scanning electron microscopy (SEM) with the magnification of 5000ט50000×, the transmission electron microscopy (TEM) with the magnification of 5000ט50000×, or the atomic force microscopy (AFM) with the scale of 10 μm˜100 μm.
As shown in
In this embodiment, because the side surface S2 of the conductive connecting region 126 has a centrally concave structure, the reflection of the light will be limited, in comparison with the case where the side surface S2 is perpendicular to the lower surface S3 or the side surface S2 is a convex surface. Moreover, in comparison with the case where the side surface S2 has a downward concave portion and the connection area between the lower surface S3 and the substrate 11 is thus decreased, this embodiment provides the larger connection area (lower surface S3) so that the problem of the conductive mesh pattern 12 easily falling off the substrate due to the insufficient connection area can be avoided.
The transmission electrodes 42 are disposed in a one-dimensional array, and the sensing electrodes 43 are disposed in a one-dimensional array. The transmission electrodes 42 are disposed adjacent to the sensing electrodes 43 and insulated from the sensing electrodes 43. The transmission electrodes 42 and the sensing electrodes 43 are electrically connected to a control unit 5 disposed on a side of the mesh pattern 41. When the user touches or clicks the touch panel 4, the transmission electrodes 42 will generate a capacitance variation signal, which is received by the sensing electrodes 43 and then transmitted to a signal processing module of the control unit 5 electrically connected to the sensing electrodes 43. Then, a coordinate signal representing the touch input can be generated by the calculation and processing. The operation of the transmission electrodes 42 and the sensing electrodes 43 can be achieved by the mutual capacitance type. In other embodiments, the operation of the transmission electrodes 42 and the sensing electrodes 43 can be achieved by the self capacitance type, which indicates the transmission electrodes 42 and the sensing electrodes 43 can sense the touch and transmit the touch signal by themselves.
Any of the above-mentioned touch panels can be combined with a display device to form a touch display device. For example, the touch panel can be disposed on the display surface of the display device, or the conductive mesh pattern is directly formed on the display surface of the display device by regarding the display surface of the display device as the substrate. Moreover, by regarding a certain layer of the display device as the substrate, the conductive mesh pattern can be directly formed on the substrate within the display device.
In summary, in the touch panel according to the invention, the conductive mesh pattern with electrical conductivity is formed on the substrate, the wires of the wire area of the conductive mesh pattern intersect to form the intersections, and a side of each of the intersections is extended to form a protrusion so that the intersection and the corresponding protrusion can form a conductive connecting region. Thereby, the signal attenuation during the transmission can be reduced and the touch input position can be thus determined precisely and rapidly.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention.