1. Field of the Invention
The present invention relates to a touch panel, and more particularly, to a touch panel for providing a shield against noise.
2. Description of the Prior Art
Advanced displays have gradually become a major feature of today's consumer electronics products. To facilitate portability and utilization, a display device having a touch panel for users to touch directly have been widely used in television sets, smart phones or other electronics products.
For a conventional optical touch device, a large number of light sources and corresponding optical sensors are disposed around a liquid crystal display (LCD) panel. The optical sensors detect the light emitted by the corresponding light sources to determine the coordinate of the touch point. Such a design causes the volume of products to increase greatly though the light transmittance does not decrease accordingly. Due to this reason, the conventional optical touch device cannot meet the requirements for ordinary portable LCDs. As for a resistive touch panel or a capacitive touch panel, additional resistors or capacitors are disposed on the panel, and the coordinate of the touch point is determined by detecting voltage variations. However, because resistors, capacitors, or other components are disposed on the panel directly, the light transmittance of the LCD panel decreases, and the overall panel thickness increases as well.
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The touch panel 10 is glued to the display panel 20. The display panel 20 also has a conductive structure such as transparent conductive thin films. The noise generated by the display panel 20 in operation disturbs the sensing performance of the X-axis conductive circuit 60 or of the Y-axis conductive circuit 70. Thus, it requires the IT industry to design a new touch panel to reduce the influence of noise.
According to the present invention, a touch panel comprises a first substrate comprising a first surface and a second surface opposite to the first surface, a plurality of first conductive circuits, disposed on the first surface of the first substrate, a plurality of second conductive circuits, disposed over the first surface of the first substrate, and a shield circuit disposed on the second surface of the first substrate. Each of the first conductive circuits comprises a plurality of first electrodes for sensing a first detecting current when an object is pressed down. Each of the second conductive circuits comprises a plurality of second electrodes for sensing a second detecting current when the object is pressed down. The shield circuit disposed on the second surface of the first substrate is used for blocking out noise, the shield circuit comprising a transparent conducting layer and a conductive ring disposed on the transparent conducting layer, the conductive ring electrically connected to a voltage supply.
In aspect of the present invention, the touch panel further comprises a second substrate disposed over the first substrate. The plurality of second conductive circuits are on the second substrate.
In aspect of the present invention, the touch panel device further comprises a flexible printed circuit board (FPC) and conducting wires disposed on the FPC. The conductive ring is a closed metallic ring electrically connected to the voltage supply through the conducting wires.
In aspect of the present invention, the touch panel device further comprises an FPC and a first conducting wire and a second conducting wire disposed on the FPC, wherein the conductive ring has a gap, two terminals of the gap of the conductive ring are connected to two voltage supplies through the first conducting wire and the second conducting wire on the FPC, respectively.
In one aspect of the present invention, the voltage supply is a direct-current (DC) voltage supply or is used for providing voltage applied on the first conductive circuit or the second conductive circuit.
In aspect of the present invention, each of the first conductive circuits is arranged along a first axis, each of the second conductive circuits is arranged along a second axis perpendicular to the first axis.
According to the present invention, a touch panel comprises a first substrate, a plurality of first conductive circuits disposed on the first substrate, a plurality of second conductive circuits disposed over the first substrate, and a plurality of shield circuits disposed on the first substrate and extending in a direction in parallel with an extending direction of the plurality of first conductive circuits. Each of the first conductive circuits comprises a plurality of first electrodes for sensing a first detecting current when an object is pressed down. Each of the second conductive circuits comprises a plurality of second electrodes for generating a second detecting current when the object is pressed down. Each of second conductive circuits extends in a direction crossing the extending direction of the plurality of first conductive circuits. Each of the shield circuits comprises a plurality of third electrodes and disposed between the two adjacent first conductive circuits, the plurality of shield circuits electrically connected to a voltage supply, for providing a shield against noise.
According to the present invention, a touch panel comprises a first substrate, a plurality of first conductive circuits disposed on the first substrate, a plurality of second conductive circuits disposed over the first substrate, a plurality of first shield circuits disposed on the first substrate and extending in a direction in parallel with an extending direction of the plurality of first conductive circuits, and a plurality of second shield circuits disposed on the first substrate and extending in a direction in parallel with the extending direction of the plurality of first conductive circuits. Each of the first shield circuits disposed between the two adjacent first conductive circuits is used for providing a shield against noise. Each of the second shield circuits disposed between the two adjacent first conductive circuits and symmetrical to one of the first shield circuits, is used for providing a shield against noise. Each of the first conductive circuits as well as the nearest first shield circuit and the nearest second shield circuit is electrically connected to a voltage supply.
Contrast to the prior art, the present invention comprises a touch panel and a display panel. The touch panel comprises a shield circuit disposed on the display panel for providing a shield against noise generated by the display panel, so that a detecting current flowing through a first conductive circuit or a second conductive circuit can be prevented from being disturbed by the noise generated by the display panel. Moreover, the shield circuit comprises a transparent conducting layer and a conductive ring thereon. The conductive ring is electrically connected to a voltage supply, so that the noise can be more effectively blocked out by the shield circuit.
These and other features, aspects and advantages of the present disclosure will become understood with reference to the following description, appended claims and accompanying figures.
The following embodiments are exemplified by referring to the accompanying drawings, for describing specific embodiments implemented by the present invention. Furthermore, directional terms described by the present invention, such as upper, lower, front, back, left, right, inner, outer, side and etc., are only directions by referring to the accompanying drawings, and thus the used directional terms are used to describe and understand the present invention, but the present invention is not limited thereto.
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The capacitive touch panel 120 comprises transparent substrates 122 and 124, a cover lens 126, a plurality of first conductive circuits 130 formed on the substrate 122, and a plurality of second conductive circuits 140 formed on the substrate 124. In another embodiment, the substrate 122 is removed, and the plurality of first conductive circuits 130 and the plurality of second conductive circuits 140 are formed on the substrate 124. The plurality of first conductive circuits 130 are arranged along a first axis, and the plurality of second conductive circuits 140 are arranged along a second axis. Preferably, the first axis is perpendicular to the second axis. Each of the first conductive circuits 130 comprises a plurality of diamond-shaped first electrodes 131. Each of the second conductive circuits 140 comprises a plurality of diamond-shaped second electrodes 141. Any two adjacent first electrodes 131 are electrically connected to each other through a first axis conducting wire 132. Any two adjacent second electrodes 141 are electrically connected to each other through a second axis conducting wire 142. To avoid any short circuit occurs between the plurality of first conductive circuits 130 and the plurality of second conductive circuits 140, the plurality of first conductive circuits 130 and the plurality of second conductive circuits 140 are formed on different substrates. The plurality of first conductive circuits 130 are formed on the substrate 122, and the plurality of second conductive circuits 140 are formed on the substrate 124. The transparent substrates 122 and 124 are made of glass or transparent macromolecule plates such as polycarbonate (PC) and polyvinyl chloride (PVC). The plurality of first electrodes 131, the plurality of second electrodes 141, the first axis conducting wire 132, and the second axis conducting wire 142 are formed by transparent conducting thin films such as ITO, aluminum zinc oxide (AZO), and indium zinc oxide (IZO). The plurality of first conductive circuits 130 are aligned along either X-axis or Y-axis perpendicular to the X-axis. Correspondingly to the plurality of first conductive circuits 130, the plurality of second conductive circuits 140 are aligned along either Y-axis or X-axis. According to the first embodiment, the plurality of first conductive circuits 130 are X-axis conductive circuits, and the plurality of second conductive circuits 140 are Y-axis conductive circuits. The cover lens 126 protects the capacitive touch panel 120 from being exposed to the outer environment directly. The cover lens 126 is a flexible transparent plate.
When a user's finger presses down on a point on the outer surface of the capacitive touch panel 120, static electricity in the user's body flows into the ground, and then a weak detecting current is produced. The detecting current passes through a first electrode 131 and a second electrode 141 corresponding to the touch point. The detecting current passing through the first electrode 131 and the second electrode 141 is transmitted to a detecting chip (not shown) through a metallic wire 136 and a metallic wire 146, respectively. Afterwards, the detecting chip determines the touch position according to the two flows of the detecting current. The detecting current is extremely weak so the outer noise has to be as little as possible in order to prevent the detecting chip from misjudging the detecting current.
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In another embodiment, the substrate 124 is removed. The first conductive circuits 130 and the second conductive circuits 140 are on one side 1221 of the substrate 122 while the shield circuits 134 are on an opposite side 1222 of the substrate 122, which is facing the display panel 110.
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The plurality of third electrodes 251 on the shield circuit 250 are diamond-shaped, or can be polygonal, circular, oval, etc. The plurality of third electrodes 251 can still have other shapes as long as the space between the two first conductive circuits 230 is well filled. These variations are all within the spirit and scope of the present invention. The cover lens 226 protects the capacitive touch panel 220 from being exposed to the outer environment directly. The cover lens 226 is a flexible transparent plate.
When a user's finger presses down on a point on the outer surface of the capacitive touch panel 220, static electricity in the user's body flows into the ground, and then a weak detecting current is produced. The detecting current passes through a first electrode 231 and a second electrode 241 corresponding to the touch point. The detecting current passing through the first electrode 231 and the second electrode 241 is transmitted to a detecting chip (not shown) through a metallic wire 236 and a metallic wire 246, respectively. Afterwards, the detecting chip determines the touch position according to the detecting current. As
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Although the present invention has been explained by the embodiments shown in the drawings described above, it should be understood to the ordinary skilled person in the art that the invention is not limited to the embodiments, but rather various changes or modifications thereof are possible without departing from the spirit of the invention. Accordingly, the scope of the invention shall be determined only by the appended claims and their equivalents.