TWI476669B - Capacitive touch panel - Google Patents

Description

Capacitive touch panel

The present invention relates to a touch panel, and more particularly to a touch panel capable of reducing noise interference.

The touch panel is roughly classified into a resistive touch panel, a capacitive touch panel, an optical touch panel, an acoustic wave touch panel, and an electromagnetic touch panel according to different sensing methods. Capacitive touch panels have been widely used in electronic products because of their fast response time, high reliability, and high durability.

The capacitive touch panel changes the capacitance value of the touch panel by approaching or touching the touch panel via a finger or a conductor material. When the touch panel detects a change in the capacitance value, it can determine the position where the finger or conductor material is close to or touched, and perform the function operation corresponding to the touch position. Due to limitations in power supply capacity, today's electronic products, such as mobile phones, tablets, etc., often need to be used while charging. However, when the electronic product is connected to the charger, the noise generated by the charger converting the AC voltage to the DC voltage will affect the detection result of the capacitance value through the ground terminal of the chip circuit in the electronic product. Further, there is a case where the touch point judgment error or the touch sensitivity is lowered to lower the use quality.

The invention provides a capacitive touch panel, which can effectively reduce the influence of noise caused by the charger on the touch operation.

The invention provides a capacitive touch panel comprising a plurality of first sensing series and a plurality of second sensing series. The plurality of first sensing series extends in the first direction, and each of the first sensing series includes a plurality of first sensing pads connected to each other. The plurality of second sensing series extends in the second direction and are interlaced with the plurality of first sensing series, each of the second sensing series includes a plurality of second sensing pads, wherein each of the second sensing pads The area of the second sensing pad includes a first sub-sensing pad and a plurality of second sub-sensing pads, wherein the first sub-sensing pad and the plurality of second sub- The sensing pads are electrically coupled to each other.

In an embodiment of the present invention, the first sensing pad further includes a plurality of branch portions, and each of the branch portions is disposed between the two second sub-sensing pads corresponding thereto, and respectively corresponding to the second The second sub-sensing pads are electrically coupled.

In an embodiment of the invention, in the same second sensing series, the first sub sensing pads of any two adjacent second sensing pads are connected to each other through a bridge wire.

In an embodiment of the invention, wherein any two adjacent first sensing pads are connected to each other through a bridge line in the same first sensing series.

In an embodiment of the invention, the first sensing series is used to transmit a scanning signal, and the second sensing series is used to transmit a sensing signal.

In an embodiment of the invention, the first direction is perpendicular to the second direction.

The invention provides a capacitive touch panel comprising a plurality of first sensing series and a plurality of second sensing series. The plurality of first sensing series extends along the first direction, and each of the first sensing series includes a plurality of first sensings connected to each other pad. The plurality of second sensing series extending in the second direction and interlaced with the plurality of first sensing series, each of the second sensing series comprising a plurality of second sensing pads connected to each other, wherein each second The area of the sensing pad is smaller than the area of each of the first sensing pads.

In an embodiment of the invention, wherein any two adjacent first sensing pads are connected to each other through a bridge line in the same first sensing series.

In an embodiment of the invention, wherein any two adjacent second sensing pads are connected to each other through a bridge line in the same second sensing series.

In an embodiment of the invention, the second sensing pad is an arrow shape.

In an embodiment of the invention, the first sensing pad is in the shape of an arrow.

In an embodiment of the invention, the first sensing series is used to transmit a scanning signal, and the second sensing series is used to transmit a sensing signal.

In an embodiment of the invention, the second sensing series is configured to transmit a scanning signal, and the first sensing series is configured to transmit a sensing signal.

In an embodiment of the invention, the first direction is perpendicular to the second direction.

Based on the above, the present invention reduces the interference voltage of the charger noise by reducing the area of the sensing pad in the sensing series for transmitting the sensing signal, thereby improving the problem of the touch point judgment error or the touch sensitivity decreasing. .

The above described features and advantages of the present invention will be more apparent from the following description.

FIG. 1 is a schematic diagram of a capacitive touch panel according to an embodiment of the invention. Referring to FIG. 1 , the capacitive touch panel 100 includes a plurality of first sensing series 102 and a plurality of second sensing series 104 , wherein the plurality of first sensing series 102 are in a first direction (also That is, the X direction shown in FIG. 1 extends, and is arranged in a manner along the second direction (that is, the Y direction shown in FIG. 1 and the first direction and the second direction are perpendicular to each other in this embodiment), and more The second sensing series 104 are arranged in a second direction and arranged in a first direction, and the first sensing series 102 is interleaved with the second sensing series 104. For ease of illustration, FIG. 1 depicts only one first sensing series 102 and one second sensing series 104.

As shown in FIG. 1, each of the first sensing series 102 includes a plurality of first sensing pads 102A connected to each other, and each of the second sensing series 104 includes a plurality of second sensing pads 104A, wherein the second The area of the sensing pad 104A is smaller than the area of the first sensing pad 102A. In this embodiment, the first sensing pad 102A is for transmitting the scanning signal TX, and the second sensing series 104 is for transmitting the sensing signal RX.

In addition, in the first sensing series 102 in this embodiment, two adjacent first sensing pads 102A are connected to each other through the bridge wire 102B. In the second sensing series 104, the first sensing pad 102A is divided into a first sub-sensing pad 104A1 and four second sub-sensing pads 104A2, wherein each second sub-sensing pad 104A2 is electrically The first sub-pads 104A1 are electrically coupled to each other, and the first sub-pads 104A1 of the two adjacent second pads 104A pass through the bridges 104B. Connect to each other. In addition, the total area of the first sub-sensing pad 104A1 and each of the second sub-sensing pads 104A2 is smaller than the first sensing pad 102A. That is, the size of the second sensing pad 104A of the second sensing series 104 for transmitting the sensing signal RX is reduced in this embodiment compared to the design of the sensing pad of the conventional touch panel. .

A background capacitance Cm1 is formed between the adjacent first sensing pad 102A and the second sensing pad 104A, and a background capacitance is also formed between the first sub sensing pad 104A1 and the plurality of second sub sensing pads 104A2. Cm2, in addition, a second self-capacitance Cearth is formed between the second sensing pad 104A and the ground. The noise caused by the charger will be generated from the ground terminal, and coupled to the output terminal T2 through the ground capacitance Cearth, thereby affecting the detection result of the touch.

The equivalent circuits formed by the background capacitors Cm1, Cm2 and the ground capacitance Cearth can be as shown in FIG. 2, wherein the background capacitor Cm1 and the background capacitor Cm2 are connected in series to the input end T1 of the scan signal TX and the output end of the output sense signal RX. Between T2, the ground self-capacitance Cearth is coupled between the output terminal T2 and the ground. The output terminal T2 is coupled to an analog converter ADC to convert the sensing signal RX into a digital signal.

It should be noted that the background capacitance Cm1 referred to in this embodiment is between each of the first sensing pads 102A and the adjacent second sensing pads 104A of the first sensing series 102 driven by the scanning signal TX. The sum of the formed capacitances, the background capacitance Cm1 shown in FIG. 1 is a simplified schematic diagram. Similarly, the background capacitance Cm2 referred to in this embodiment is the first sensing pad 102A in the first sensing series 102 driven by the scanned signal TX. The sum of the capacitances formed between the first sub-sensing pad 104A1 and the plurality of second sub-sensing pads 104A2 in the adjacent second sensing pad 104A, and the background capacitance Cm2 illustrated in FIG. 1 is a simplified schematic diagram.

As shown in FIG. 2, the area of the second sensing pad 104A for transmitting the sensing signal RX is reduced in comparison with the sensing pad of the conventional touch panel, and thus the second sensing pad 104A and the ground are The self-capacitance Cearth formed between the ends will be smaller than that of the conventional technology, so that the interference of the charger noise to the sensing signal RX can be greatly suppressed. When the area of the second sensing pad 104A is reduced to 1/2 or less, the interference of the charger noise to the sensing signal RX can be suppressed to 1/2 or less. While maintaining the shape of the first sensing pad 102A without dividing the second sensing pad 104A, the resistance value of the first sensing series 102 can be avoided.

In addition, the result of dividing the second sensing pad 104A into one first sub-sensing pad 104A1 and the plurality of second sub-sensing pads 104A2 causes the background capacitance to drop substantially. as shown in picture 2. The first sensing pad 102A and the second sensing pad 104A have only the background capacitance Cm1 when the second sensing pad 104A is not divided, and the second sensing pad 104A is divided by the background. The capacitor Cm1 is connected in series with the background capacitance Cm2, which can greatly reduce the capacitance of the background capacitor. Since the division of the second sensing pad 104A does not significantly affect the finger capacitance formed when the finger is touched, the signal-to-noise ratio of the sensing signal RX received by the analog-to-digital converter ADC can be improved. In the case where the digital code of the analog digital converter ADC is not saturated, a larger finger capacitance value can be sensed. In addition, the smaller background capacitance can also reduce the charge and discharge of the first sensing series 102. The power consumption required.

It is to be noted that the division of the second sensing pad 104A is not limited to the embodiment of FIG. 1 , and the schematic diagram of the capacitive touch panel of another embodiment of the present invention as shown in FIG. 3 may also be The second sensing pad 104A is divided into a first sub-sensing pad 104A1 and six second sub-sensing pads 104A2, and the shapes of the first sub-sensing pad 104A1 and the second sub-sensing pad 104A2 are also not limited. The second sub-sensing pad 104A2 of an embodiment may include a diamond shape and a triangle shape.

In addition, the background capacitance can also be reduced by changing the shape of the first sensing pad 102A, as shown in FIG. 4, which is a schematic diagram of a capacitive touch panel according to another embodiment of the present invention. In this embodiment, the first sensing pad 102A further includes a plurality of branch portions B1, wherein each of the branch portions B1 is respectively disposed between the two second sub-sensing pads 104A2 corresponding thereto, and respectively corresponding to The two second sub-pads 104A2 are electrically coupled such that the capacitance in series with the background capacitance is increased to further reduce the background capacitance.

It should be noted that, in some embodiments, the second sensing pad 104A may not be divided, and the area may be reduced only by changing the shape. As shown in FIG. 5, the capacitive touch panel of another embodiment of the present invention is as shown in FIG. In the schematic diagram, the second sensing pad 104A can be changed to the shape of an arrow to reduce the area of the second sensing pad 104A. In addition, in other embodiments, the first sensing pad 102A and the second sensing pad 104A may also be changed into the shape of an arrow (as shown in FIG. 6 ), so as to meet the requirements in some embodiments, the first An application in which the sense string 102 is interchanged with the second sense train 104 role.

In summary, the present invention reduces the second used to transmit the sensing signal. Sensing the size of the second sensing pad in series to suppress interference of the charger noise to the sensing signal. In addition, by dividing the second sensing pad to reduce the capacitance of the background capacitance, the signal-to-noise ratio of the sensing signal is increased, and the power consumption required for charging and discharging the first sensing series is reduced.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧Capacitive touch panel

102‧‧‧First sensing series

104‧‧‧Second sensing series

102A‧‧‧First sensing pad

104A‧‧‧Second sensing pad

102B, 104B‧‧‧Bridge wiring

TX‧‧‧ scan signal

RX‧‧‧ sensing signal

104A1‧‧‧First sub-sensing pad

104A2‧‧‧Second sub-sensing pad

Cm1, Cm2‧‧‧ background capacitance

Cearth‧‧‧Self capacitance

T1‧‧‧ input

T2‧‧‧ output

ADC‧‧‧ Analog Digital Converter

B1‧‧‧ Branch

FIG. 1 is a schematic diagram of a capacitive touch panel according to an embodiment of the invention.

FIG. 2 is a schematic diagram showing an equivalent circuit of the capacitive touch panel of the embodiment of FIG. 1. FIG.

3 to 6 are schematic views of a capacitive touch panel according to an embodiment of the invention.

100‧‧‧Capacitive touch panel

102‧‧‧First sensing series

104‧‧‧Second sensing series

102A‧‧‧First sensing pad

104A‧‧‧Second sensing pad

102B, 104B‧‧‧Bridge wiring

TX‧‧‧ scan signal

RX‧‧‧ sensing signal

104A1‧‧‧First sub-sensing pad

104A2‧‧‧Second sub-sensing pad

Cm1, Cm2‧‧‧ background capacitance

Cearth‧‧‧Self capacitance

Claims (13)

A capacitive touch panel includes: a plurality of first sensing series extending along a first direction, each of the first sensing series comprising a plurality of first sensing pads connected to each other; and a plurality of second The sensing series extends along a second direction and is interlaced with the first sensing series, each of the second sensing series includes a plurality of second sensing pads, wherein each of the second sensing pads An area smaller than an area of each of the first sensing pads, and each of the second sensing pads includes: a first sub-sensing pad; and a plurality of second sub-sensing pads, wherein the first sub-sensing pad and the The second sub-sensing pads are electrically coupled to each other. The capacitive touch panel of claim 1, wherein the first sensing pad further comprises a plurality of branch portions, each of the branch portions being respectively disposed on the two second sub-sensing pads corresponding thereto And electrically coupled to the corresponding two second sub-sensing pads respectively. The capacitive touch panel of claim 1, wherein in the same second sensing series, the first sub sensing pads of any two adjacent second sensing pads are connected to each other through a bridge wire . The capacitive touch panel of claim 1, wherein in the same first sensing series, any two adjacent first sensing pads are connected to each other through a bridge wire. The capacitive touch panel of claim 1, wherein the first sensing series is for transmitting scanning signals, and the second sensing series is for transmitting sensing signals. The capacitive touch panel of claim 1, wherein The first direction is perpendicular to the second direction. A capacitive touch panel includes: a plurality of first sensing series extending along a first direction, each of the first sensing series comprising a plurality of first sensing pads connected to each other; and a plurality of second The sensing series extends along a second direction and is interlaced with the first sensing series, each of the second sensing series includes a plurality of second sensing pads connected to each other, wherein each of the second senses The area of the test pad is smaller than the area of each of the first sensing pads, and the second sensing pad is in the shape of an arrow. The capacitive touch panel of claim 7, wherein in the same first sensing series, any two adjacent first sensing pads are connected to each other through a bridge wire. The capacitive touch panel of claim 7, wherein in the same second sensing series, any two adjacent second sensing pads are connected to each other through a bridge wire. The capacitive touch panel of claim 7, wherein the first sensing pad is in the shape of an arrow. The capacitive touch panel of claim 7, wherein the first sensing series is for transmitting scanning signals, and the second sensing series is for transmitting sensing signals. The capacitive touch panel of claim 7, wherein the second sensing series is configured to transmit a scanning signal, and the first sensing series is configured to transmit a sensing signal. The capacitive touch panel of claim 7, wherein the first direction is perpendicular to the second direction.