1. Field of the Invention
The application relates to a touch panel, and more particularly, to a capacitive touch panel.
2. Description of Related Art
As information technology, wireless mobile communication and information appliances have been rapidly developed and applied, to achieve more convenience, more small volume, light weight and more user-friendly designs, various information products have changed from using conventional input devices such as key boards or mice to using touch panels.
Based on different sensing types, a touch sensing panel can be generally categorized into a resistive touch sensing panel, a capacitive touch sensing panel, an optical touch sensing panel, an acoustic-wave touch sensing panel, and an electromagnetic touch sensing panel. In comparison to other touch panels, the capacitive touch sensing panel is characterized by short response speed, favorable reliability, high definition, and so on. Therefore, the capacitive touch panel is widely used in the electronic products.
The present application is directed to a touch panel capable of enhancing quality of signal transmission and sensing sensitivity.
The application provides a touch panel, including a substrate, a plurality of conductive lines, a plurality of conductive pads, a plurality of connecting lines, a plurality of ground lines and a plurality of dummy pads. The substrate has a first surface. The conductive lines are arranged abreast on the first surface and respectively extended along a first direction. The conductive pads are disposed on the first surface, in which N conductive pads are present between two adjacent conductive lines. The connecting lines are disposed on the first surface and respectively connected to the conductive pads. In which, 1 to N conductive pads located between an i-th conductive line to a (i+1)-th conductive line are respectively connected to 1 to N connecting lines. The 1 to N connecting lines are arranged abreast and located between the 1 to N conductive pads and the (i+1)-th conductive line. j and n are positive integers. The ground lines are arranged abreast on the first surface and respectively extended along a first direction, in which an i-th ground line is located between the (i+1)-th conductive line and the corresponding 1 to N connecting lines. The dummy pads are disposed on the first surface and located between the (i+1)-th conductive line and the corresponding 1 to N connecting pads.
In view of above, in order to adjust a distance between the conductive lines and the corresponding conductive pads, the application is directed to dispose a plurality of dummy pads without participating circuitry layout to be located between the conductive lines and the corresponding conductive pads on the touch panel, so as to reduce parasitic capacitance generated between the conductive lines and the corresponding conductive pads. Further, by disposing the dummy pads between the conductive lines and the corresponding conductive pads, the uneven transmittance (caused by the distance between the conductive lines and the corresponding conductive pads being too long) while disposing the touch panel on the backlight module may also further be reduced. Moreover, the application is further directed to dispose ground lines between the conductive lines and the corresponding connecting lines, so as to reduce poor signal transmission due to interference between two adjacent conductive lines which are arranged abreast.
To make the above features and advantages of the invention more comprehensible, several embodiments accompanied with drawings are described in detail as follows.
Accordingly, the conductive lines Ry1 to Ryi and the conductive pads Tx1 to TxN are alternately disposed in order to accomplish a sensing process in terms of planes. When a user touches the touch panel 100 with a finger, the conductive lines Ry1 to Ryi
and the conductive pads Tx1 to TxN may cause variation in capacitance on a contact position where the finger touches. The touch panel 100 may calculate a coordinate of the contact position using said variation in capacitance and transmit the coordinate to an electronic device connected thereto. Generally, if the conductive lines Ry1 to Ryi and the conductive pads Tx1 to TxN are alternately disposed on different planes, the touch panel 100 may generate a visual difference. Therefore, in the present embodiment, by disposing the conductive lines Ry1 to Ryi and the conductive pads Tx1 to TxN on the same plane, a thickness of the touch panel 100 may be reduced and a transmittance thereof may be increased, accordingly. As a result, when the touch panel 100 is integrated with a display panel as a display having a touch-control function, the touch panel 100 may have better optical properties.
Two adjacent conductive lines Ry1 and Ry2 and devices therebetween as illustrated in
As shown in
Accordingly, the connecting lines CL1 to CLN may extend to a bridge area 114 of the touch panel 100, and the connecting lines CL1 to CLN are electrically connected along the second direction D2 through bridging devices on the bridge area 114 for respectively forming said 1 to N sensing series. In the present embodiment, the touch panel 100 includes a first bridge area 114 and a second bridge area 116 respectively located one two opposite sides of the substrate 110. The touch panel 100 further includes a first flexible printed circuit board 170a and a second flexible printed circuit board 170b respectively disposed on the first bridge area 114 and the second bridge area 116, and the first flexible printed circuit board 170a and the second flexible printed circuit board 170b are electrically connected to each other. A portion of the connecting lines CL1 to CLN are electrically connected to the first flexible printed circuit board 170a, whereas another portion for the connecting lines CL1 to CLN are electrically connected to the second flexible printed circuit board 170b. According to such configuration, since all connecting lines CL1 to CLN are respectively connected to the bridge areas 114 and 116 on two opposite sides of the substrate 110, wiring space on the touch panel 100 may be greatly reduced, thereby reducing overall size of the touch panel 100. Nonetheless, the application is not limited thereto. According to other embodiments of the invention, the connecting lines CL1 to CLN may also be connected to a same side of the substrate 110. Such configuration may be accomplished, for example, by disposing a flexible printed circuit board on a bridge area of the touch panel, in which the bridge area is located on a side of the substrate 110, and the connecting lines CL1 to CLN are electrically connected to the flexible printed circuit board.
In the present embodiment, a material of the connecting lines CL1 to CLN may be conductive transparent materials such as Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), Al doped zinc oxide (AZO) or Indium Oxide or a combination thereof. Practically, according to the present embodiment, the conductive lines Ry1 to Ryi have an identical width and the conductive pads Tx1 to TxN also have an identical size. However, the application is not limited thereto. According to other embodiments of the invention, the conductive pads Tx1 to TxN may also have a different size, which may be adjusted based on requirements such as contact area (such as size of the finger) or sensing resolution.
Accordingly, in the present embodiment, the ground lines GL1 to GLi-1 are arranged abreast on the first surface 112 and extended along the first direction D 1. Particularly in the present embodiment, the ground lines GL1 to GLi-1 are respectively disposed between the conductive lines and connecting lines adjacent thereto, so as to reduce poor sensing sensitivity due to electrical interference generated by the conductive lines and adjacent connecting lines. As shown in
Moreover, when the conductive lines Ry1 to Ryi and the corresponding conductive pads Tx1 to TxN are too close to each other, parasitic capacitance generated therebetween may affect normal operation of the touch panel. Therefore, a proper distance is required to space apart the conductive lines Ry1 to Ryi and the corresponding conductive pads Tx1 to TxN. However, in the case where the distance between the conductive lines Ry1 to Ryi and the corresponding conductive pads Tx1 to TxN is increased, the touch panel 100 may face problems such as difficulty in fabricating process and an uneven transmittance. Accordingly, in the present embodiment, dummy pads 160 are disposed between the conductive lines and the corresponding 1 to N conductive pads to adjust the distance between the conductive lines Ry1 to Ryi and the corresponding conductive pads Tx1 to TxN, so that touch panel 100 may operate normally, and degree of uniformity in transmittance of the touch panel 100 may also be maintained. Herein, the dummy pads 160 are only used to space apart the conductive lines Ry1 to Ryi and the corresponding conductive pads Tx1 to TxN without participating the circuitry layout.
In view of above, in order to adjust a distance between the conductive lines and the corresponding conductive pads, the application is directed to dispose a plurality of dummy pads without participating circuitry layout to be located between the conductive lines and the corresponding conductive pads on the touch panel, so as to reduce parasitic capacitance generated between the conductive lines and the corresponding conductive pads. Further, by disposing the dummy pads between the conductive lines and the corresponding conductive pads, the uneven transmittance (caused by the distance between the conductive lines and the corresponding conductive pads being too long) while disposing the touch panel on the backlight module may also further be reduced. Moreover, the application is further directed to dispose ground lines between the conductive lines and the corresponding connecting lines, so as to reduce poor signal transmission due to interference between two adjacent conductive lines which are arranged abreast.
Although the invention has been described with reference to the above embodiments, it is apparent to one of the ordinary skill in the art that modifications to the described embodiments may be made without departing from the spirit of the invention. Accordingly, the scope of the invention will be defined by the attached claims not by the above detailed descriptions.
This application claims the priority benefits of U.S. provisional application Ser. No. 61/583,205, filed on Jan. 5, 2012. The entirety of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification.
Number | Date | Country | |
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61583205 | Jan 2012 | US |