News Column

Researchers Submit Patent Application, "Touch Panel and Manufacturing Method Thereof", for Approval

August 20, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors Wu, Yuan-Chun (Taoyuan County, TW); Lee, Hsin-Hung (Hsinchu City, TW); Ma, Mei-Sheng (Taipei City, TW); Yang, Tun-Chun (Taipei City, TW); Lee, Seok-Lyul (Hsinchu City, TW); Hsieh, Yao-Jen (Hsinchu County, TW), filed on March 28, 2014, was made available online on August 7, 2014.

The patent's assignee is Au Optronics Corporation.

News editors obtained the following quote from the background information supplied by the inventors: "The present invention generally relates to a touch panel and a manufacturing method thereof, in particular, to a touch panel having improved visual effect and a manufacturing method thereof.

"Along with the development of electronics industry, the designs of digital products, such as mobile phones, personal digital assistants (PDAs), notebook computers, and tablet computers, are all going towards convenience, multi-functionality, and attractive appearance. The displays of these digital products are the most indispensable communication interfaces which allow users of these products to operate them conveniently. Among all the displays, liquid crystal display (LCD) has become the mainstream of today's display market.

"In recent years, along with the development of information and wireless communication technologies and the widespread of various information products, the conventional input devices (for example, keyboards or mousse) of many information products have been replaced by touch panels in order to make these information products more convenient, small-sized, light-weighted, and personalized, wherein touch panel LCD is the most commonly adopted product.

"FIGS. 1A.about.1C illustrate a conventional touch panel, wherein FIG. 1A is a 3-dimensional view of the touch panel, FIG. 1B is a perspective view of the touch panel, and FIG. 1C is a cross-sectional view of the touch panel. For the convenience of description, FIG. 1A and FIG. 1B illustrate only the sensing pad structure in the touch panel, while FIG. 1C illustrates some other layers, such as a substrate and other dielectric layers, of the touch panel.

"As shown in FIGS. 1A.about.1C, the conventional touch panel 100 includes a substrate 110, a plurality of first sensing serials 120, a first dielectric layer 130, a plurality of second sensing serials 140, and a second dielectric layer 150. To be specific, the first sensing serials 120 are disposed on the substrate 110 and extended along a first direction, wherein each of the first sensing serials 120 is composed of a plurality of first sensing pads 122 and a plurality of first bridging lines 124 which are connected in series. The first dielectric layer 130 is disposed on the substrate 110 and covers the first sensing serials 120. The second sensing serials 140 are disposed on the first dielectric layer 130 and extended along a second direction, wherein each of the second sensing serials 140 is composed of a plurality of second sensing pads 142 and a plurality of second bridging lines 144 which are connected in series. The projections of the first sensing pads 122 and the second sensing pads 142 form a sensing array on the substrate 110 so as to achieve planar sensing.

"As described above, when a user touches the touch panel 100 with a finger, the first sensing pads 122 and the second sensing pads 142 of the touch panel 100 produce an electrical change (for example, a voltage drop or a current change) at where the finger touches the touch panel 100. The electrical change is transformed into a control signal and transmitted to a control circuit board. A central processing unit (CPU) carries out data processing and calculations according to the control signal, and then the control circuit board outputs a display signal to a display device and thereby to display image by the display device.

"However, in foregoing conventional touch panel, the sensing pads are disposed in different layers therefore may have different characteristics (for example, different transmittances) due to variations in subsequent fabrication processes. Moreover, the transmittance uniformity of the entire touch panel may also be affected by the positions of the sensing pads or the light distance difference of reflected lights since the sensing pads are disposed in different layers. All of foregoing facts may cause the problem of color shift in the touch panel.

"On the other hand, when the touch panel is integrated with a display device, a user can easily become aware of the sensing pads in the touch panel, and the difference between those areas disposed with and without sensing pads can be very obvious. Thereby, how to improve the transmittance uniformity of a touch panel and accordingly improve the visual effect thereof is currently one of the major subjects in the manufacturing of touch panels."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "Accordingly, the present invention is directed to a touch panel, wherein the problem of color shift is effectively overcome and accordingly the visual effect of the touch panel is improved.

"The present invention is directed to a touch panel having good transmittance, and a good display quality can be achieved when the touch panel is applied in a display device.

"The present invention is also directed to a method for manufacturing a touch panel.

"The present invention provides a touch panel including a substrate, at least one first sensing serial, and at least one second sensing serial. The first sensing serial is disposed on the substrate and extended along a first direction. The first sensing serial includes a plurality of first sensing pads and a plurality of first bridging lines, wherein each of the first bridging lines connects adjacent two first sensing pads in series. The second sensing serial is disposed on the substrate and extended along a second direction, wherein the first direction intersects the second direction. The second sensing serial includes a plurality of second sensing pads and a plurality of second bridging lines, wherein the first sensing pads are coplanar to the second sensing pads, and each of the second bridging lines connects adjacent two second sensing pads in series.

"According to an embodiment of the present invention, the touch panel further includes a first dielectric layer and a plurality of via holes. The first dielectric layer is disposed on the substrate and covers the first sensing serial and the second sensing pads, and the second bridging lines are located on the first dielectric layer. The via holes are disposed in the first dielectric layer, and the second bridging lines are connected to the corresponding second sensing pads through the corresponding via holes. In addition, the touch panel may further include a second dielectric layer disposed on the first dielectric layer and covering the first sensing serial and the second sensing serial.

"According to an embodiment of the present invention, the touch panel further includes a first dielectric layer. The first dielectric layer is disposed on the substrate and covers the first sensing serial, and the first dielectric layer has a plurality of openings corresponding to the second sensing pads. The second sensing pads are located in the corresponding openings, and each of the second bridging lines spans over the first dielectric layer between adjacent two openings and connects the corresponding adjacent two second sensing pads. In addition, the touch panel may further include a second dielectric layer disposed on the first dielectric layer and covering the first sensing serial and the second sensing serial.

"According to an embodiment of the present invention, the touch panel further includes a first dielectric layer and a plurality of via holes. The first dielectric layer is disposed on the substrate and covers the first bridging lines, and the first sensing pads and the second sensing serial are located on the first dielectric layer. The via holes are disposed in the first dielectric layer, and the first sensing pads are connected to the corresponding first bridging lines through the corresponding via holes. In addition, the touch panel may further include a second dielectric layer disposed on the first dielectric layer and covering the first sensing serial and the second sensing serial.

"According to an embodiment of the present invention, the touch panel further includes a plurality of dummy patterns, wherein each of the dummy patterns is located between a first sensing pad and an adjacent second sensing pad. Each of the dummy patterns may be in strip shape.

"According to an embodiment of the present invention, each of the first sensing pads and each of the second sensing pads may respectively have at least one opening for forming a hollow portion, and the hollow portion may include a trellis pattern or a plurality of strip patterns.

"The present invention also provides a touch panel including a substrate, at least one first sensing serial, a first dielectric layer, at least one second sensing serial, a second dielectric layer, a plurality of first dummy sensing pads, and a plurality of second dummy sensing pads. The first sensing serial is disposed on the substrate and extended along a first direction. The first sensing serial includes a plurality of first sensing pads and a plurality of first bridging lines, wherein each of the first bridging lines connects adjacent two first sensing pads in series. The second dummy sensing pads are disposed on the substrate. The first dielectric layer is disposed on the substrate and covers the first sensing serial and the second dummy sensing pads. The second sensing serial is disposed on the substrate and extended along a second direction, wherein the first direction intersects the second direction, and the first sensing serial and the second sensing serial are located on different planes. The second sensing serial includes a plurality of second sensing pads and a plurality of second bridging lines, wherein each of the second bridging lines connects adjacent two second sensing pads in series. The first dummy sensing pads are disposed on the first dielectric layer and are corresponding to the first sensing pads. The second dielectric layer is disposed on the first dielectric layer and covers the second sensing serial and the first dummy sensing pads.

"According to an embodiment of the present invention, the touch panel further includes a plurality of first dummy patterns, wherein each of the first dummy patterns is located between a first sensing pad and an adjacent second dummy sensing pad. In addition, the touch panel may further include a plurality of second dummy patterns, wherein each of the second dummy patterns is located between a first dummy sensing pad and an adjacent second sensing pad. The first dummy patterns or the second dummy patterns may be in strip shape.

"The present invention further provides a method for manufacturing a touch panel. First, a substrate is provided, and at least one first sensing serial and at least one second sensing serial are formed on the substrate. The first sensing serial is disposed on the substrate and extended along a first direction, and the second sensing serial is disposed on the substrate and extended along a second direction, wherein the first direction intersects the second direction. The first sensing serial includes a plurality of first sensing pads and a plurality of first bridging lines, wherein each of the first bridging lines connects adjacent two first sensing pads in series. The second sensing serial includes a plurality of second sensing pads and a plurality of second bridging lines, wherein the second sensing pads are coplanar to the first sensing pads, and each of the second bridging lines connects adjacent two second sensing pads in series.

"According to an embodiment of the present invention, foregoing manufacturing method may include following steps. First, the first sensing pads, the first bridging lines, and the second sensing pads are formed on the substrate to make the first sensing pads, the first bridging lines, and the second sensing pads to be coplanar. After that, a first dielectric layer is further formed on the substrate to cover the first sensing pads, the first bridging lines, and the second sensing pads. Besides, a plurality of via holes are formed in the first dielectric layer, and then the second bridging lines are formed on the first dielectric layer, so that the second bridging lines can be connected to the corresponding second sensing pads through the corresponding via holes.

"According to an embodiment of the present invention, the manufacturing method may include following steps. First, the first sensing serial is formed on the substrate. After that, a first dielectric layer is further formed on the substrate to cover the first sensing serial. Besides, a plurality of openings are formed in the first dielectric layer, and then the second sensing serial is formed, wherein the second sensing pads of the second sensing serial are formed in the corresponding openings to be coplanar to the first sensing pads, and each of the second bridging lines of the second sensing serial spans over the first dielectric layer between adjacent two openings to connect corresponding adjacent two second sensing pads.

"According to an embodiment of the present invention, the manufacturing method may include following steps. First, the first bridging lines are formed on the substrate. After that, a first dielectric layer is further formed on the substrate to cover the first bridging lines. Besides, a plurality of via holes are formed in the first dielectric layer, and then the first sensing pads and the second sensing serial are formed on the first dielectric layer, wherein the first sensing pads, the second sensing pads, and the second bridging lines are coplanar, and the first sensing pads are connected to the corresponding first bridging lines through the corresponding via holes.

"According to an embodiment of the present invention, the manufacturing method may further include forming a second dielectric layer on the first dielectric layer to cover the first sensing serial and the second sensing serial.

"According to an embodiment of the present invention, the manufacturing method may further include forming a plurality of dummy patterns while forming the first sensing pads or the second sensing pads, wherein each of the dummy patterns is located between a first sensing pad and an adjacent second sensing pad.

"According to an embodiment of the present invention, the manufacturing method may further include respectively forming at least one opening in each of the first sensing pads and each of the second sensing pads so as to form a hollow portion.

"The present invention further provides a method for manufacturing a touch panel. First, a substrate is provided. Next, a plurality of first sensing pads, a plurality of first bridging lines, and a plurality of second dummy sensing pads are formed on the substrate, wherein each of the first bridging lines connects adjacent two first sensing pads in series to form at least one first sensing serial, and the first sensing serial is extended along a first direction. After that, a first dielectric layer is formed on the substrate to cover the first sensing pads, the first bridging lines, and the second dummy sensing pads. Next, a plurality of second sensing pads, a plurality of second bridging lines, and a plurality of first dummy sensing pads are formed on the first dielectric layer, wherein each of the second bridging lines connects adjacent two second sensing pads in series to form at least one second sensing serial, and the second sensing serial is extended along a second direction, and the second direction intersects the first direction. The first dummy sensing pads are corresponding to the first sensing pads, and the second sensing pads are corresponding to the second dummy sensing pads. After that, a second dielectric layer is formed on the first dielectric layer to cover the second sensing pads, the second bridging lines, and the first dummy sensing pads.

"According to an embodiment of the present invention, the manufacturing method may further include forming a plurality of first dummy patterns while forming the first sensing pads, the first bridging lines, and the second dummy sensing pads, wherein each of the first dummy patterns is located between a first sensing pad and an adjacent second dummy sensing pad. In addition, the manufacturing method may further include forming a plurality of second dummy patterns while forming the second sensing pads, the second bridging lines, and the first dummy sensing pads, wherein each of the second dummy patterns is located between a second sensing pad and an adjacent first dummy sensing pad.

"According to the present invention, in a touch panel having a double-layered sensing pad structure, dummy sensing pads are disposed on each layer corresponding to the sensing pads on the other layer for compensating the color shift of the touch panel and to improve the visual effect thereof. Additionally, according to the present invention, the sensing pads may also be formed on the same plane so as to form a touch panel having a single-layered sensing pad structure, and various patterns for connecting the sensing pads in different directions are provided. Since the sensing pads are all disposed on the same plane, the problem of color shift is avoided and the display uniformity of the entire touch panel is improved. On the other hand, in the present invention, dummy patterns may be disposed between adjacent sensing pads in order to further improve the visual effect of the touch panel; Or, at least one opening may be formed on each sensing pad to form a hollow portion on the sensing pad so that the visual effect of the touch panel, and accordingly the transmittance thereof, can be further improved.

BRIEF DESCRIPTION OF THE DRAWINGS

"The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

"FIGS. 1A.about.1C illustrate a conventional touch panel.

"FIGS. 2A.about.2C illustrate a touch panel according to an embodiment of the present invention.

"FIGS. 3A.about.3D illustrate a manufacturing method of a touch panel according to an embodiment of the present invention.

"FIGS. 4A.about.4C illustrate a touch panel according to another embodiment of the present invention.

"FIG. 5 illustrates a single-layered sensing pad structure of a touch panel according to an embodiment of the present invention.

"FIGS. 6A.about.6B, 7A.about.7B, and 8A.about.8C illustrate a manufacturing method of a touch panel having a single-layered sensing pad structure according to an embodiment of the present invention.

"FIGS. 9A.about.9B, 10A.about.10B, and 11A.about.11C illustrate a manufacturing method of a touch panel having a single-layered sensing pad structure according to another embodiment of the present invention.

"FIGS. 12A.about.12B, 13A.about.13B, and 14A.about.14C illustrate a manufacturing method of a touch panel having a single-layered sensing pad structure according to yet another embodiment of the present invention.

"FIG. 15 illustrates a touch panel and the relative positions of the sensing pads and dummy patterns thereof according to an embodiment of the present invention.

"FIG. 16 illustrates a touch panel and the sensing pads thereof which are disposed with openings according to another embodiment of the present invention."

For additional information on this patent application, see: Wu, Yuan-Chun; Lee, Hsin-Hung; Ma, Mei-Sheng; Yang, Tun-Chun; Lee, Seok-Lyul; Hsieh, Yao-Jen. Touch Panel and Manufacturing Method Thereof. Filed March 28, 2014 and posted August 7, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=4563&p=92&f=G&l=50&d=PG01&S1=20140731.PD.&OS=PD/20140731&RS=PD/20140731

Keywords for this news article include: Electronics, Circuit Board, Au Optronics Corporation.

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Source: Electronics Newsweekly


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