TW201640308A - Flexible circuit board and self-capacitive touch panel using the same - Google Patents

Abstract

A self-capacitive touch panel includes a patterned transparent conductive layer, a flexible circuit board, and a plurality of wires. The flexible circuit board includes a board body, a plurality of bonding pads, and at least one auxiliary pad. The board body has a bonding surface and a non-bonding surface opposite to each other. The bonding pads are disposed on the bonding surface. The auxiliary pad is disposed on the non-bonding surface. The bonding pads and the auxiliary pad are electrically connected to different scanning elements of a controller. Each of the wires is electrically connected between the patterned transparent conductive layer and the corresponding bonding pad.

Description

Flexible circuit board and self-capacitive touch panel using the same

The invention relates to a flexible circuit board and a self-capacitive touch panel using the same.

Today's touch technology has been widely used in various electronic devices. By sensing the specific position of the touch panel, the specific position is sensed, and then the sensing signal is transmitted to the processing unit for processing by the processing unit through a flexible circuit board electrically connected to the touch panel. Analysis, in order to achieve the purpose of inputting data or instructions to the electronic device.

The projected capacitive touch panel is currently the mainstream of touch technology development, and the projected capacitive touch panel can be divided into a mutual capacitive touch panel and a self-capacitive touch panel according to different measurement principles. Among them, the self-capacitive touch panel has a good application in some fields due to its simple structure and low power consumption. The self-capacitive touch panel detects the change in capacitance of the conductive pattern itself, that is, detects the capacitance of the X-axis and Y-axis sensing electrodes themselves (ie, the capacitance of the electrodes and the ground, also referred to as electrostatic capacitance). When the finger approaches or touches the screen, the capacitance of the finger is superimposed on the screen capacitor to increase the total capacitance. The scanning circuit is scanned in sequence during scanning. The X-axis and Y-axis sensing electrodes are drawn, and the coordinate position of the touched point is determined according to the change in capacitance before and after the scanning.

Generally, in the self-capacitive touch panel, in order to avoid signal misreading by superimposing the capacitance of the touch conductor such as a finger on the lead of the non-touch operation area, it is necessary to directly bond the FPC to the end of the conductive pattern of the touch panel. Electrical connection, this method does not need lead wires or leads are short, so the influence of the capacitance of the touch conductor can be neglected, and the touch signal can be accurately judged, but the disadvantage is that the entire joint area of the FPC and the touch panel is wider, which will affect subsequent Arrangement of physical buttons and logo patterns.

Therefore, how to propose a flexible circuit board that can solve the above problems (reducing the width of the joint area without causing misreading of the touch signal) and the capacitive touch panel using the same are the current research and development resources of the industry. One of the projects for research.

The invention provides a flexible circuit board comprising: a plate body having an opposite joint surface and a non-joining surface; a plurality of joint pads disposed on the joint surface; and at least one auxiliary mat disposed on the non-joining surface The bonding pad and the auxiliary pad are electrically connected to different scanning channels of a processing unit, respectively.

In an embodiment of the invention, the bonding pad sequentially receives the scanning of the processing unit and the auxiliary pad continues to receive the scanning by the processing unit.

In an embodiment of the invention, the material of the auxiliary pad is a conductive material.

In an embodiment of the invention, the material of the auxiliary pad is copper.

In an embodiment of the present invention, the installation position of the auxiliary pad and the installation position of the bonding pad correspond to each other via the plate body.

In an embodiment of the invention, the number of the at least one auxiliary pad is plural, and the auxiliary pads are electrically connected to each other.

In an embodiment of the invention, the auxiliary pad overlaps each bonding pad via a plate body.

In an embodiment of the invention, the board body comprises an insulating substrate, an inner circuit layer and a cover film, wherein the bonding pad and/or the auxiliary pad and the inner circuit layer are simultaneously formed on the insulating substrate by the same material, and the cover film At least cover the internal circuit layer.

The present invention also provides a self-capacitive touch panel comprising any one of the above flexible circuit boards, further comprising: a transparent conductive pattern layer; and a plurality of leads, each of which is electrically connected to the transparent conductive pattern layer With the corresponding bonding pads.

In an embodiment of the invention, the lead wire and the transparent conductive pattern layer are made of the same material.

In an embodiment of the invention, the self-capacitive touch panel further includes a transparent substrate, and a touch area and a peripheral area are defined on one surface thereof, wherein the transparent conductive pattern layer is disposed in the touch area, and the lead is Set in the surrounding area.

In summary, the transparent conductive pattern layer of the self-capacitive touch panel of the present invention is electrically concentrated to the bonding region via the wires, and is bonded to the flexible circuit board. The bond pads on the face are bonded so that the overall width of the land of the flexible circuit board is reduced. At the same time, the self-capacitive touch panel of the present invention further provides at least one auxiliary pad on the non-joining surface of the flexible circuit board, which can be used as a reference signal receiving point, and can be disposed at a position corresponding to the position of the bonding pad on the bonding surface. Corresponding to, and lead to a reference signal channel of the processing unit. With the above configuration, when the user's finger approaches the peripheral area, the lead and the auxiliary pad adjacent thereto are simultaneously affected (i.e., the same or similar sensing signals are generated). In other words, the reference signal receiving point can receive a similar superimposed capacitance when the finger approaches the peripheral area, and is sent to the processing unit as a reference value through the reference signal path. Therefore, after the bonding pad on the bonding surface of the flexible circuit board receives the capacitance signal from the touch area and the peripheral area and transmits the signal to the processing unit, the processing unit can automatically deduct the corresponding reference value sensed by the auxiliary pad (which can be processed by the software) Assist), you can optimize the touch effect, so as to accurately determine the touch signal from the touch area, to a large extent avoid signal misreading.

12‧‧‧Self-capacitive touch panel

120‧‧‧Transparent substrate

120a‧‧‧ touch area

120b‧‧‧ surrounding area

120c‧‧‧ junction area

122‧‧‧Transparent conductive pattern layer

126‧‧‧ lead

13, 33‧‧‧Soft circuit board

131‧‧‧ board

131a‧‧‧Insulation substrate

131b‧‧‧Internal circuit layer

131c‧‧‧ Cover film

13a‧‧‧ joint surface

13b‧‧‧non-joined

132‧‧‧ Bonding mat

133, 333‧‧ ‧ auxiliary pads

134‧‧‧ wire

14‧‧‧Processing unit

FIG. 1 is an exploded view of a self-capacitive touch panel according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view showing the flexible circuit board in Fig. 1 along the line segment 4-4'.

Fig. 3 is a front elevational view showing the non-joining surface of the flexible circuit board in Fig. 2.

Fig. 4 is a cross-sectional view showing a flexible circuit board according to an embodiment of the present invention corresponding to a fifth line segment 5-5'.

Fig. 5 is a cross-sectional view showing a flexible circuit board according to another embodiment of the present invention corresponding to the fifth line segment 5-5'.

Fig. 6 is a cross-sectional view showing the flexible circuit board according to another embodiment of the present invention, taken along line 4-4', corresponding to Fig. 1.

Fig. 7 is a front elevational view showing the non-joining surface of the flexible circuit board in Fig. 6.

The embodiments of the present invention are disclosed in the following drawings, and the details of However, it should be understood that these practical details are not intended to limit the invention. That is, in some embodiments of the invention, these practical details are not necessary. In addition, some of the conventional structures and elements are shown in the drawings in a simplified schematic manner in order to simplify the drawings.

Please refer to FIG. 1 . FIG. 1 is an exploded view of a self-capacitive touch panel according to an embodiment of the present invention. As shown in FIG. 1 , in the present embodiment, the self-capacitive touch panel 12 includes a transparent substrate 120 , a transparent conductive pattern layer 122 , a flexible circuit board 13 , and a plurality of leads 126 . A touch area 120a and a peripheral area 120b located on at least one side of the touch area 120a are defined on the surface of the transparent substrate 120. A bonding area 120c may be defined at a suitable position in the peripheral area 120b for a subsequent process requirement, and is used for softness. The board is electrically connected. The transparent conductive pattern layer 122 is disposed in the touch area 120a, and the lead 126 is disposed in the peripheral area 120b. The electrodes in the transparent conductive pattern layer 122 are electrically concentrated to the bonding region 120c of the transparent substrate 120. The transparent conductive pattern layer 122 can be directly formed on the surface of the transparent substrate 120 by sputtering, etching, or the like, but the invention is not limited thereto.

It should be understood that the touch area 120a and the peripheral area 120b described above only clearly define the relative relationship between the transparent conductive pattern layer 122 and the leads 126. The actual surface of the transparent substrate 120 does not necessarily have a specific mark to distinguish The presence of the touch area 120a and the peripheral area 120b.

In one embodiment, the lead 126 and the transparent conductive pattern layer 122 are made of the same material and are simultaneously produced. Therefore, compared with the conventional visible area pattern and other metal conductive trace forms, the embodiment can reduce at least one process and reduce the cost. the goal of. However, in practical applications, the lead 126 and the transparent conductive pattern layer 122 may also be different materials.

In one embodiment, the material of the transparent conductive pattern layer 122 and the lead 126 includes Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), and Aluminum Zinc Oxide (AZO). However, the invention is not limited thereto.

In one embodiment, the transparent substrate 120 is made of glass or plastic. The plastic is, for example, a transparent sheet made of polycarbonate (PC), polyester (PET), polymethyl methacrylate (PMMA) or cycloolefin copolymer (COC). However, the invention is not limited thereto.

Although the present invention electrically connects and concentrates the transparent conductive pattern layer 122 to the bonding region 120c of the transparent substrate 120 through the leads 126 and then bonds with a flexible circuit board, the width of the entire bonding region 120c can be reduced, and the bonding region 120c can be arranged. Position, but if it is joined with a traditional flexible circuit board, When the user's finger is close to the concentrated area of the lead 126 (near the bonding area 120c), the finger is capacitively coupled to the lead 126, and the touch is offset (ie, the user's actual touch position and the transparent conductive pattern). An error occurs between the touch positions sensed by the layer 122, and thus a problem of erroneous operation is apt to occur. In order to solve this problem, the present invention has been specifically modified for a flexible circuit board and will be explained in detail below.

Please refer to FIG. 2 to FIG. 3 again. FIG. 2 is a cross-sectional view of the flexible circuit board in FIG. 1 along the line segment 4-4′; FIG. 3 is a diagram showing the soft circuit board in FIG. Front view of the joint. The flexible circuit board 13 includes a board body 131, a plurality of bonding pads 132, and a plurality of auxiliary pads 133. The plate body 131 has opposite joint faces 13a and non-joining faces 13b, wherein the joint faces 13a are joined to the transparent substrate 120, and the bond pads 132 are disposed on the joint faces 13a, and electrically connected to one end of the leads 126 on the transparent substrate 120. connection. The auxiliary pad 133 is disposed on the non-joining surface 13b so as to be disposed on the non-joining surface 13b near the concentrated area of the lead 126 (usually in the vicinity of the bonding area 120c), that is, the position of the auxiliary pad 133 is spaced from the setting position of the bonding pad 132. The plate body 131 corresponds to each other. One end of each lead 126 is electrically connected to the transparent conductive pattern layer 122, and the other end is electrically connected to the corresponding bonding pad 132 by ACF adhesive pressing. The method of electrically connecting the transparent conductive pattern layer 122 to the bonding pad 132 on the bonding surface 13a of the flexible circuit board 13 via the wire 126 can reduce the overall width of the bonding region 120c of the flexible circuit board 13 and is convenient according to the physics. The position of the button and logo pattern requires a reasonable arrangement of the location of the land 120c.

In an embodiment of the present invention, the flexible circuit board 13 may further include a processing unit 14 which is an integrated circuit (Integrated Circuit, IC) wafer, but the invention is not limited thereto. In the present embodiment, the processing unit 14 is located on the bonding surface 13a of the flexible circuit board 13, for example, the bonding pads 132 and the auxiliary pads 133 are electrically connected to different processing units of the processing unit 14 through different channels inside the flexible circuit board 13, respectively. aisle. For example, the bonding pad 132 is electrically connected to the sensing channel of the processing unit 14 through a line inside the flexible circuit board 13. The scanning processing unit 14 sequentially scans the X-axis and Y-axis sensing electrodes of the transparent conductive pattern layer 122 through the sensing channel, and according to The change of the capacitance before and after the scan determines the coordinate position of the touch point; and the auxiliary pad 133 is electrically connected to the processing unit 14 through the internal circuit of the flexible circuit board 13 to distinguish the transparent conductive pattern from the sensing channel, for example, the reference channel. Simultaneously with the layer 122, the scanning of the auxiliary pad 133 is continuously scanned to detect whether there is a change in capacitance. However, in other embodiments of the present invention, the processing unit 14 may not be located on the flexible circuit board 13 and may exist independently of the flexible circuit board 13. The present invention is not limited thereto.

Further, in the embodiment, the auxiliary pads 133 are electrically connected to each other by a wire 134. It is preferable that the non-joining surface 13b is disposed close to the concentrated region of the lead 126 (generally in the vicinity of the joint region 120c), that is, the installation position of the auxiliary pad 133 and the installation position of the bonding pad 132 correspond to each other via the plate body 131. The non-joining surface 13b of the plate body 131 is disposed on a side close to the concentrated area of the lead wire 126, and is generally disposed corresponding to the plate body 131 at a position where the bonding pad 132 is disposed. Preferably, each of the auxiliary pads 133 is interposed between the plate body 131. The overlap with the corresponding bonding pads 132 can further shield the influence of the finger capacitance on the bonding pads 132. With the structural arrangement, when the flexible circuit board 13 is engaged with the self-capacitive touch panel 12, when the user's finger touches the touch area 120a of the self-capacitive touch panel 12 and is close to the peripheral area 120b, The lead 126 and the auxiliary pad 133 adjacent thereto have an influence at the same time (ie produces the same or similar induced signal). In other words, the reference signal receiving point represented by the auxiliary pad 133 can receive a similar capacitance value of the capacitance superimposed by the finger on the lead 126 when the finger touches the touch area 120a and is close to the peripheral area 120b, and is sent through the reference signal channel. The processing unit 14 is used as a reference value. Therefore, after the bonding pad 132 on the bonding surface 13a of the flexible circuit board 13 receives the capacitance signal from the touch area 120a and the peripheral area 120b and transmits it to the processing unit 14, the processing unit 14 can automatically deduct the sensing of the auxiliary pad 133. The corresponding reference value (assisted by the operation software) can optimize the touch effect, thereby accurately determining the touch signal from the touch area 120a, and largely avoiding the problem of misoperation.

In order to further explain the structure of the flexible circuit board 13, please refer to FIG. 4 again. FIG. 4 is a cross-sectional view showing the flexible circuit board according to the third embodiment of the line 5-5' of the embodiment of the present invention. In the present embodiment, the plate body 131 includes an insulating base material 131a, an internal wiring layer 131b, and a cover film 131c. The insulating substrate 131a is usually a material such as polyethylene terephthalate Polyester (PET) or polyimine (PI), and serves as a base and a support for the entire flexible circuit board 13. The inner circuit layer 131b is formed on a surface of the insulating substrate 131a as a conductive material, usually a plurality of thin wires made of copper foil for electrical conduction; in a preferred embodiment, the bonding pad 132 ( Or the auxiliary pad 133) is made of the same material and in synchronization with the internal wiring layer 131b, and the same layer is provided on the insulating substrate 131a. The cover film 131c, which typically also includes a material such as PET, PI, etc., covers at least the inner wiring layer 131b to protect the inner wiring layer 131b and expose the bonding pad 132 (or the auxiliary pad 133). On the other surface of the insulating base material 131a, an auxiliary pad 133 (or a bonding pad 132) is provided at a position corresponding to the plate body 131 at a position where the bonding pad 132 (or the auxiliary pad 133) is disposed, and the auxiliary pad 133 (or The pad 132) is a conductive material, preferably made of a copper foil, and is electrically connected to the inner wiring layer 131b through a through hole in the insulating base material 131a.

Fig. 5 is a cross-sectional view showing a flexible circuit board according to another embodiment of the present invention corresponding to the fifth line segment 5-5'. In another embodiment of the present invention, the inner wiring layer 131b is provided on both surfaces of the insulating base material 131a, and the cover film 131c is disposed correspondingly. The double inner wiring layer 131b can be electrically connected by providing a through hole in the insulating substrate 131a. When the circuit of the circuit is too complicated, the single layer board cannot be wired, or a copper foil is required for the grounding mask, the double interior is required. A flexible circuit board of the circuit layer 131b. In this embodiment, the bonding pad 132 and/or the auxiliary pad 133 are preferably formed on the insulating substrate 131a in the same material and in synchronization with the internal wiring layer 131b of the surface on which it is located.

In other embodiments of the present invention, the bonding pads 132 and/or the insulating pads may not be disposed in the same layer as the inner wiring layer 131b, but may be disposed on the cover film 131c through the through holes on the cover film 131c and the internal wiring. The layer 131b is electrically connected.

Please refer to Figure 6 and Figure 7. Fig. 6 is a cross-sectional view showing the flexible circuit board according to another embodiment of the present invention, taken along line 4-4', corresponding to Fig. 1. Fig. 7 is a front elevational view showing the non-joining surface of the flexible circuit board in Fig. 6.

Referring to FIGS. 1 , 6 , and 7 , the flexible circuit board 33 of the present embodiment also includes a board body 131 , a plurality of bonding pads 132 , and a processing unit 14 . Therefore, the structures of these components and the connection relationship between them can be Refer to the above related content, and will not repeat them here. Here, the flexible circuit board 33 of the present embodiment differs from the flexible circuit board 13 of the embodiment shown in FIGS. 1 to 3 in that the flexible circuit board 33 of the present embodiment is in the board. Body 131 The non-joining surface 13b is provided with only a single elongated auxiliary pad 333, and the non-joining surface 13b of the plate body 131 is disposed on a side close to the concentrated area of the lead 126, and is generally disposed at a position opposite to the position of the bonding pad 132 via the plate 131. The corresponding side, by the configuration of the structure, when the user's finger touches the touch area 120a and approaches the peripheral area 120b, the same or similar sensing signals are simultaneously generated for the lead 126 and the auxiliary pad 333 adjacent thereto. Therefore, after the bonding pad 132 on the bonding surface 13a of the flexible circuit board 33 receives the capacitance signal from the touch area 120a and the peripheral area 120b and transmits it to the processing unit 14, the processing unit 14 can automatically deduct the sensing of the auxiliary pad 333. After sensing the signal, the touch effect can also be optimized. Preferably, the auxiliary pad 333 is preferably disposed corresponding to the bonding area where each bonding pad 132 is located via the plate body 131 to further shield the influence of the finger capacitance on the bonding pad 132.

From the above detailed description of the specific embodiments of the present invention, it can be clearly seen that the transparent conductive pattern layer of the self-capacitive touch panel of the present invention is electrically concentrated to the bonding region via the leads, and the bonding surface with the flexible circuit board. The upper bonding pads are bonded so that the overall width of the bonding area of the flexible circuit board is reduced. In the meantime, the self-capacitive touch panel of the present invention further provides at least one auxiliary pad on the non-joining surface of the flexible circuit board, which can be used as a reference signal receiving point, and can be disposed close to the lead concentrated area and led to the processing unit. On a reference signal path. With the above configuration, when the user's finger approaches the peripheral area, the lead and the auxiliary pad adjacent thereto are simultaneously affected. In other words, the reference signal receiving point can receive a superimposed capacitance similar to the lead when the finger approaches the peripheral area, and is sent to the processing unit as a reference value through the reference signal path. Therefore, after the bonding pad on the bonding surface of the flexible circuit board receives the capacitance signal from the touch area and the peripheral area and transmits the signal to the processing unit, the processing unit can automatically deduct the auxiliary pad. The corresponding reference value sensed can optimize the touch effect, thereby accurately determining the touch signal from the touch area, and largely avoiding the problem of misoperation.

The present invention has been disclosed in the above embodiments, and is not intended to limit the scope of the present invention, and the invention may be modified and modified in various ways without departing from the spirit and scope of the invention. The scope is subject to the definition of the scope of the patent application.

12‧‧‧Self-capacitive touch panel

120‧‧‧Transparent substrate

120a‧‧‧ touch area

120b‧‧‧ surrounding area

120c‧‧‧ junction area

122‧‧‧Transparent conductive pattern layer

13‧‧‧Soft circuit board

131‧‧‧ board

13a‧‧‧ joint surface

132‧‧‧ Bonding mat

126‧‧‧ lead

14‧‧‧Processing unit

Claims (11)

A flexible circuit board comprising: a plate body having an opposite engagement surface and a non-joining surface; a plurality of bonding pads disposed on the bonding surface; and at least one auxiliary pad disposed on the non-joining surface, wherein the board The bonding pads and the auxiliary pads are electrically connected to different scanning channels of a processing unit, respectively. The flexible circuit board of claim 1, wherein the bonding pads sequentially receive scanning of the processing unit and the auxiliary pad continues to receive scanning by the processing unit. The flexible circuit board of claim 1, wherein the material of the auxiliary pad is a conductive material. The flexible circuit board of claim 1, wherein the auxiliary pad is made of copper. The flexible circuit board of claim 1, wherein the auxiliary pad is disposed at a position corresponding to the position of the bonding pads. The flexible circuit board of claim 1, wherein the number of the at least one auxiliary pads is plural, and the auxiliary pads are electrically connected to each other. The flexible circuit board of claim 6, wherein the auxiliary pad overlaps each of the bonding pads via the board. The flexible circuit board of claim 1, wherein the board comprises an insulating substrate, an inner wiring layer, and a cover film, and the bonding pads and/or the auxiliary pads are simultaneously the same as the inner circuit layer. A material is formed on the insulating substrate, the cover film covering at least the inner wiring layer. A self-capacitive touch panel comprising the flexible circuit board of any one of claims 1 to 10, further comprising: a transparent conductive pattern layer; and a plurality of leads, each of the The leads are electrically connected to the transparent conductive pattern layer and the corresponding bonding pads. The self-capacitive touch panel of claim 9, wherein the leads are the same material as the transparent conductive pattern layer. The self-capacitive touch panel of claim 9, further comprising a transparent substrate, wherein a touch area and a peripheral area are defined on one surface, wherein the transparent conductive pattern layer is disposed in the touch area, and The leads are disposed in the peripheral region.