TWM472897U - Capacitive touch screen and a wireless electronic device with the capacitive touch screen - Google Patents

Description

Capacitive touch screen and wireless electronic device with the same

The implementation of the present invention relates to the field of capacitive touch screen manufacturing technology. More specifically, embodiments of the present invention relate to a capacitive touch screen and a wireless electronic device having the capacitive touch screen.

This section is intended to provide a background or context for the implementation of the present invention as set forth in the claims. The description herein may include concepts that may be explored, but not necessarily concepts that have been previously contemplated or have been explored. Therefore, the contents described in this section are not prior art to the specification and claims of the present application, and are not admitted to be prior art.

As an input medium, the touch screen is the most simple, convenient and natural human-machine dialogue mode. Therefore, touch screens are increasingly being applied to various electronic devices such as mobile phones, notebook computers, MP3/MP4, and the like. In order to reduce the cost of electronic devices and make electronic devices thinner and lighter, touch screens are usually integrated in liquid crystal display panels. According to the working principle and the detection of touch information media, the touch screen can be divided into four types: resistive, capacitive, infrared and surface acoustic waves. Capacitance The touch screen technology has become the mainstream touch screen technology due to its simple process, long product life and high light transmittance.

The capacitive touch screen has signal transceivers, including the receiving end and the transmitting end. The basic working principle is to adopt the working mode of TX+RX, that is, the transmitting end sends a driving electric signal of a certain frequency and amplitude, and is received by the receiving end. And detecting the received touch sensing signal at the receiving end to determine whether a touch occurs. Various wireless electronic products, which are typical applications of capacitive touch screens, also have signal transceiving devices, and their basic functions often include transmitting and receiving various radio frequency (RF) signals, such as GSM signals, CDMA signals or WIFI signals.

However, during the research, the creator discovered that when the capacitive touch screen in the prior art is applied to a wireless electronic device, the capacitive touch screen and the transceiver device of various wireless electronic devices are simultaneously integrated into a small space, and When the capacitive touch screen is applied to various wireless electronic devices in the prior art, the radio frequency signal of the wireless electronic device may interfere with the electrical signal induced by the capacitive touch screen, resulting in a capacitive touch screen. Performance is declining.

Therefore, there is a great need for a capacitive touch screen to reduce the interference of the RF signal on the electrical signal induced by the capacitive touch screen when the capacitive touch screen is applied to various wireless electronic devices, and the capacitive touch type is improved. The performance of the screen.

In this context, embodiments of the present disclosure are directed to providing an improved capacitive touch screen and wireless having the capacitive touch screen Electronic equipment.

In the embodiment of the present invention, a capacitive touch screen is provided for use in a wireless electronic device, including: a capacitive touch screen body, a flexible circuit board, and the capacitive touch screen body and the flexible circuit A connecting wire of the board, the connecting wire being located in a portion of the near field region radiated by the antenna of the wireless electronic device is a connecting wire of low conductivity.

Compared with the prior art, when the capacitive touch screen provided by the present embodiment is applied to a wireless electronic device, the portion of the connecting wire located in the near field region of the antenna of the wireless electronic device is low in conductivity. Connecting wires, because the low conductivity connecting wires have the function of reducing electromagnetic wave radiation, when the radio frequency signal of the antenna radiates to the vicinity of the connecting wires, the electromagnetic wave energy radiated to the inside of the connecting wires can be reduced, and the radio frequency conducted to the inside of the connecting wires can be weakened The strength of the signal, thereby reducing the interference of the RF signal on the electrical signal induced by the capacitive touch screen when the capacitive touch screen is applied to the wireless electronic device, and improving the performance of the capacitive touch screen.

Preferably, the connection guide is located in a near field region of the wireless electronic device antenna, and a portion within a range of 20 mm from the antenna is a low conductivity connecting wire.

In an embodiment of the present invention, the portion of the connecting wire located outside the near-field region of the antenna radiation is a high conductivity connecting wire.

Preferably, the ohms per square of the high conductivity connecting wires is less than 10 ohms/square.

More preferably, the high conductivity connecting wire is a copper wire, Silver paste line or graphene line.

In another embodiment of the present invention, the portion of the connecting wire located outside the near-field region of the antenna radiation is a low conductivity connecting wire.

Preferably, the low conductivity connecting wire is an indium tin oxide wire or a nano silver wire.

In still another embodiment of the present invention, the capacitive touch screen body includes an electrode pattern area and a touch button area, and the touch electrodes of the touch button area are electrodes of low conductivity.

In another embodiment of the present invention, the connecting wire is located in a portion of the near-field region of the antenna radiating and has a curved shape.

In still another embodiment of the present invention, the shape of the trace of the connecting wire located outside the near-field region of the antenna radiation is curved.

Preferably, the curved shape is curved or wavy.

A wireless electronic device, including the capacitive touch screen of any of the above, is also provided in the implementation of the present invention.

Preferably, the wireless electronic device is a mobile phone, a tablet computer, a wireless netbook or a notebook computer.

1‧‧‧electrode pattern area

2‧‧‧Touch button area

3‧‧‧Flexible circuit board

4‧‧‧Connecting wires

41‧‧‧The connecting wire is located in the near-field area of the antenna radiation

42‧‧‧Connected wires are located outside the near-field area of the antenna radiation

5‧‧‧埠5

301‧‧‧埠301

302‧‧‧埠302

303‧‧‧埠303

O10‧‧‧ Transmission coefficient frequency response curve of the channel between 埠5 and 埠301 in the traditional capacitive touch screen

N10‧‧‧ Transmission coefficient frequency response curve of the channel between 埠5 and 埠301 in the capacitive touch screen provided by the creative implementation

O12‧‧‧ Transmission coefficient frequency response curve of the channel between 埠5 and 埠302 in the traditional capacitive touch screen

N12‧‧‧ Transmission coefficient frequency response curve of the channel between 埠5 and 埠302 in the capacitive touch screen provided by the creative embodiment

O14‧‧‧ Transmission coefficient frequency response curve of the channel between 埠5 and 埠303 in the traditional capacitive touch screen

N14‧‧‧ Transmission coefficient frequency response curve of the channel between 埠5 and 埠303 in the capacitive touch screen provided by the creative embodiment

Plane electromagnetic waves transmitted along the Z-axis at EMI‧‧‧埠5

6‧‧‧Compared metal pieces for mobile phone antennas

1 is a schematic structural view of a capacitive touch screen in the prior art; FIG. 2 is a schematic structural view of a capacitive touch screen provided in an embodiment; FIG. 3 is a diagram in FIG. Partial magnification of the capacitive touch screen structure FIG. 4 is a schematic structural view of a capacitive touch screen provided in another embodiment of the present invention; FIG. 5 is a schematic structural view of a capacitive touch screen provided in another embodiment of the present invention; FIG. 6 is a schematic structural view of a capacitive touch screen provided in another embodiment of the present invention; FIG. 7 is a schematic diagram of a periodic square wave signal; FIG. 8 is a schematic diagram provided in an embodiment of the present invention. In the capacitive touch screen, the 埠 distribution of the scattering model is shown; the ninth figure is a partial enlarged view of the 埠 distribution of the scattering model in the capacitive touch screen shown in FIG. 8; the 10th is the conventional capacitive touch In the capacitive touch screen provided in one embodiment of the present invention, the transmission coefficient frequency response curve comparison diagram of the channel between 埠5 and 埠301 is in the screen; FIG. 11 shows that the RF signal source is 900 MHz respectively. , 1.8 GHz and 2.4 GHz, in the conventional capacitive touch screen and in the capacitive touch screen provided in one embodiment of the present invention, the transmission coefficient comparison table of the channel between 埠5 and 埠301; FIG. 12 is a schematic diagram showing a comparison of transmission coefficient frequency response curves of channels between 埠5 and 埠302 in a conventional capacitive touch screen and a capacitive touch screen provided in an embodiment of the present invention; Figure 13 is a diagram showing that the radio frequency signal sources are 900 MHz, 1.8 GHz, and 2.4 GHz, respectively, in a conventional capacitive touch screen and in a capacitive touch screen provided in an embodiment of the present invention, 埠5 to 埠302 The transmission coefficient comparison table between the channels; the 14th figure is the transmission coefficient frequency of the channel between the 埠5 and the 埠303 in the conventional capacitive touch screen and the capacitive touch screen provided in one embodiment of the present creation The response curve is compared with the schematic diagram; the 15th figure is when the RF signal sources are 900 MHz, 1.8 GHz, and 2.4 GHz, respectively, in the conventional capacitive touch screen and in the capacitive touch screen provided in one embodiment of the present invention, Between 5 and 303, the transmission coefficient comparison table of the channel; FIG. 16 is a schematic diagram of the 埠 distribution of the radiation model in the capacitive touch screen provided in one embodiment of the present invention; and FIG. 17 is a conventional capacitive touch The average electric field strength values at 埠301, 埠302, and 埠303 in the control screen; Figure 18 is the average electric field strength at 埠301, 埠302, and 埠303 in the capacitive touch screen provided by the present embodiment. Value; Figure 19 A schematic diagram of the location of the mobile phone antenna in the wireless electronic device with the capacitive touch screen provided in one embodiment of the present invention; FIG. 20 is a conventional capacitive touch screen and the capacitive touch provided by the present creative embodiment In the control screen, the RF average electric field strength value generated by the electrical signal of the capacitive touch screen received by the metal piece of the mobile phone antenna Compare the schematics.

As mentioned above, the creator discovered during the research that when the capacitive touch screen in the prior art is applied to a wireless electronic device, there is a phenomenon that the RF signal interferes with the capacitive touch screen induced electrical signal.

As shown in FIG. 1 , when the capacitive touch screen of the prior art is applied to a wireless electronic device, the method includes: a capacitive touch screen body, comprising an electrode pattern area 1 and a touch button area composed of a plurality of driving electrodes and sensing electrodes; 2, wherein the touch button area 2 is located near an antenna (not shown) for receiving and transmitting a radio frequency signal by the wireless electronic device, wherein the plurality of driving electrodes and sensing electrodes are used for receiving and transmitting electrical signals; The circuit board 3 is provided with a capacitive touch screen control circuit. The capacitive touch screen control circuit provides a driving signal for the driving electrode via the connecting wire 4, and is connected on the other hand. The wire 4 receives the electrical signal induced by the sensing electrode. It should be understood that the structural diagram described in FIG. 1 is for illustrative purposes only, and is not intended to limit the scope of the present invention. In some cases, it may be increased depending on the specific situation or Reduce some structures.

The working principle of the capacitive touch screen is: when the finger touches the touch screen, a coupling capacitor is formed between the finger and the touch screen, and the coupling capacitor causes the driving electrode and the sensing electrode of the touch screen. The self-capacitance of the ground increases, or the mutual capacitance at the intersection of the drive electrode and the sense electrode decreases.

For mutual capacitance detection, the transmitting end of the capacitive touch screen control circuit sends a driving signal to the driving electrode through the connecting wire, and the sense is passed. The sensing electrode generates an inductive signal, and then returns to the receiving end of the capacitive touch screen control circuit via the connecting wire. The sensing signal generated by the sensing electrode is affected by the mutual capacitance of the driving electrode and the sensing electrode becoming smaller and correspondingly occurring. The change is such that the capacitive touch screen control circuit determines the touch position according to the change of the sensing signal.

For self-capacitance detection, the transmitting end of the capacitive touch screen control circuit sends a driving signal to the driving electrode or the sensing electrode through the connecting wire, and the driving electrode or the sensing electrode generates an sensing signal, and returns to the capacitive touch screen control via the connecting wire. At the receiving end of the circuit, the sensing signal generated by the driving electrode or the sensing electrode is correspondingly changed by the influence of the self-capacitance of the driving electrode and the sensing electrode on the ground, thereby utilizing the capacitive touch screen control circuit according to the The change in the sensing signal determines the touch position.

The creator further studied and found that for the radio frequency signal transmitted by the wireless electronic device through its antenna, the connecting wire is equivalent to a receiving antenna. When the wireless electronic device transmits the radio frequency signal through the antenna, the connecting wire receives the radio frequency signal at this time, and is Conducted to the sensing electrode, causing interference to the sensing signal generated by the sensing electrode, affecting the detection of the sensing signal by the signal receiving end of the touch screen control circuit, and reducing the performance of the capacitive touch screen.

The creator further researched and found that the anti-interference ability of the capacitive touch screen control circuit can be improved: filtering by software algorithm, or improving the anti-interference ability of the system in the application circuit design, or adjusting the physics in the structural design. Position, or use a mask to weaken electricity When a touch screen is used in various wireless electronic devices, the radio frequency signal causes interference to the electrical signal. However, these solutions have certain limitations. Among them, the first scheme will increase the complexity of the control circuit and lead to an increase in cost; the second scheme may affect the touch performance of the capacitive touch screen; the third scheme There is a need to increase the area of the board and increase the cost; the fourth option is more demanding on the structural design.

Based on the above research, the present invention provides a capacitive touch screen and a wireless electronic device having the capacitive touch screen, which can significantly reduce or eliminate the radio frequency signal pair transmitted by the wireless electronic device through the antenna thereof. The interference of the induced electrical signal of the capacitive touch screen. The principles and spirit of the present work will be described below with reference to a few exemplary embodiments. It should be understood that these embodiments are presented only to enable a person skilled in the art to understand the invention, and the scope of the present invention is not limited in any way. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

The present invention provides a capacitive touch screen for use in a wireless electronic device, including: a capacitive touch screen body, a flexible circuit board, and a connecting wire connecting the capacitive touch screen body and the flexible circuit board The portion of the connecting wire located in the near field region of the antenna of the wireless electronic device is a low conductivity connecting wire.

The capacitive touch screen applied to the wireless electronic device provided by the creative embodiment, wherein the connecting wire is located in a near-field region of the antenna of the wireless electronic device, and is a low-conductivity connecting wire for the wireless electronic device. For the transmitted RF signal, the connecting wire is equivalent to a receiving antenna. The connecting wire can be calculated from the following formula, ie "antenna", the resistance R _ANT and the quality factor Q: R _ANT = R _DC + R _AC (1)

The square resistance of the material R:

Quality factor Q:

Where R _ANT represents the total resistance of the "antenna", R _DC represents the DC resistance of the "antenna", R _AC represents the alternating current resistance of the "antenna", ρ represents the conductivity of the "antenna" material, and N represents the number of turns of the "antenna"; I(m) indicates the length (unit, meter) of the "antenna", D (m) indicates the width (unit, meter) of the "antenna", and T (m) indicates the thickness (unit, meter) of the "antenna" plating. μ ₀ represents the permeability in vacuum, μ _r represents the relative permeability of the "antenna" material, L represents the inductance of the "antenna", and f represents the frequency of the radio frequency (RF) signal.

It can be seen from equations (1) to (5) that when the width D of the "antenna", the thickness T of the plating layer, the length I, the magnetic permeability of the material μ ₀ μ _r, and the frequency f of the radio frequency (RF) signal are constant, "antenna" The resistance R _ANT is proportional to the conductivity ρ and the number of turns N of the material, and the quality factor Q is inversely proportional to its resistance R _ANT . Therefore, when N is fixed, ρ is the conductivity of the material is low, "antenna" in the larger resistance R _ANT, Q the lower the quality factor, and, to the receive antenna, the lower the quality factor Q, receive antenna The worse the performance of the RF signal, therefore, the low conductivity connecting wire has the function of reducing the electromagnetic wave radiation, so that the capacitive touch screen provided in the present embodiment can reduce the effect of electromagnetic wave radiation, thereby weakening the capacitance. When the touch screen is applied to a wireless electronic device, the RF signal interferes with the induced electrical signal when the capacitive touch screen operates.

In order to make the above objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Specific details are set forth in the following description in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in a variety of other ways than those described herein, and those skilled in the art can make similar promotions without violating the meaning of the present invention. The present invention is therefore not limited by the specific implementations disclosed below.

Exemplary device one:

As shown in FIG. 2 and FIG. 3 , the present invention provides a capacitive touch screen, including a capacitive touch screen body, comprising: an electrode pattern area 1 and a touch button composed of a plurality of driving electrodes and sensing electrodes; Zone 2, wherein the touch button zone 2 is located in the vicinity of an antenna (not shown) for receiving and transmitting radio frequency signals in the wireless electronic device, and the plurality of driving electrodes and sensing electrodes are used for receiving and transmitting electrical signals; the flexible circuit board (FPC) 3 and connecting the capacitive touch screen body and the flexible circuit board (FPC) A connecting wire 4 of 3, wherein the portion 41 of the connecting wire 4 located in the near-field region of the antenna of the wireless electronic device is a connecting wire of low conductivity. The stack structure of the capacitive touch screen may be G/F/F (glass + film + film structure), or G/G (glass + glass structure), or G/F (glass + film structure), Or OGS (a single-layer glass structure in which a capacitive touch screen is integrated into a liquid crystal display panel); the capacitive touch screen can be operated in a self-capacitance mode, a mutual capacitance mode, or a self-protection integrated mode; The flexible circuit board 3 is provided with a capacitive touch screen control circuit. In other implementations of the present invention, the capacitive touch screen control circuit can also be disposed in the main circuit board and through the flexible circuit board. The capacitive touch screen is electrically connected; the connecting wire 4 may be any one of a plurality of connecting wires of the flexible circuit board 3 and the capacitive touch screen body, and may also include the flexible circuit board 3 and the capacitor Many of the plurality of connecting wires of the touch screen body are not limited in this creation.

It should be noted that, in the technical field, a material having a square resistance greater than 10 ohms/square is generally defined as a low conductivity material, and a material having a square resistance of 10 ohms/square or less is defined as a high conductivity material, and therefore, In the authoring embodiment, the low conductivity connecting wires are preferably connecting wires having a square resistance greater than 10 ohms/square.

It should also be noted that the field area around the antenna in the wireless electronic device is divided into three areas according to the distance from the antenna: the reactance near field area, also called the reactive near field area or the induction near field area, which is the antenna radiation field. In a near-field region in the vicinity of the antenna aperture, the reactive energy storage field dominates. Generally, the boundary of the region is taken from the antenna aperture surface λ / π , in which the electric field component and the magnetic field component have phases. Poor, electromagnetic energy alternately transforms in this region, does not radiate energy outward; radiates the near-field region, and exceeds the reactance near-field region to the near-field region of radiation, also known as the "Fresnel region". In the region, the radiation field predominates, the electromagnetic energy is separated from the antenna and radiated outward in the form of electromagnetic waves, and the angular distribution of the radiation field is related to the distance from the antenna aperture; the far field field is radiated, also known as "Fei and Fei The region (Fraunhofer region), the electric field and the magnetic field have the same phase, forming energy radiation. In this region, the angular distribution of the radiation field is independent of the distance. Strictly speaking, only the distance from the antenna reaches the sky. The far-field region, but in a certain distance, the angle of the radiation field distribution of the error is within the allowable range, i.e., the point to infinity the region is called a far field radiation angle distribution at infinity.

Generally, the boundary between the near-field region and the far-field region of the radiation, that is, the Rayleigh distance between the Fresnel region and the Fraunhofer boundary, is determined by the wave path difference: "From the source antenna, the spherical wavefront is reached. The wave path difference between the edge of the antenna to be tested and the center of the antenna to be tested is λ /16", that is, R = 2D ² / λ (6)

Where R is the distance from the antenna to be measured to the boundary of the far-field region, and D is the maximum size of the physical aperture of the antenna. The so-called maximum size of the physical aperture refers to: assuming that the antenna is wrapped with a sphere, the smallest diameter of the sphere. .), λ is the operating wavelength.

It should also be noted that the above definition of the boundary between the far-field region and the near-field region of the radiation is generally defined, but it is not applicable to the definition of the boundary between the far-field region and the near-field region of the radiated antenna. The so-called small electric antenna refers to an antenna whose antenna length is small compared with the wavelength in the entire working frequency band, and the length of the electric small antenna defined by the HAWheeler satisfies:

In wireless electronic devices with small electric antennas, such as mobile phones (the antenna built into the mobile phone belongs to the small antenna), the definition of the boundary between the far-field region and the radiated near-field region requires additional criteria.

The additional criterion is that the judgment condition is that the total amplitude of the near-field component of the radiation is sufficiently lower than the total amplitude of the far-field component of the radiation, and if the near-field of the radiation is added by random phase, the resulting peak is recorded. The valley fluctuation is ΔL (dB), and the additional conditions for the test distance are:

Where R is the test distance (m) of the reactive near-field level of the antenna to be tested, and ΔL is the distance peak-to-valley fluctuation (dB) caused by the rotation of the antenna to be tested. If the near-field component of the radiation is attenuated according to 1/r ² and r is the distance from the source antenna to the antenna to be tested, it is often required that the near-field component of the radiation is at least 35 dB lower than the far-field component of the radiation, and the peak-valley fluctuation ΔL 0.3dB, R ^' = 10λ.

The additional criterion is that the judgment condition is that rotating the antenna to be tested causes the change of the test distance r to have little effect on the measured result, and still limits the peak-valley fluctuation of the distance to ΔL (dB), then:

Where R ^" is the test distance (m) of the antenna to be tested when the rotation effect is determined, D _m is the maximum mechanical size (m) of the antenna, and ΔL is the distance peak-valley fluctuation error caused by the rotation of the antenna to be tested (dB) And, the fluctuation of the distance between the center of the phase of the antenna to be tested and the source antenna is D _m /2.

In an embodiment of the present invention, the wireless electronic device is a mobile phone, and the second additional criterion is adopted, and the peak-to-valley fluctuation uncertainty ΔL is 0.5 dB, D _m =100 mm, and is calculated according to the formula (9). The minimum rotation distance of the antenna to be tested is small enough to be ^" R ^" = 164 mm, which means that the boundary between the far field and the near field in the present embodiment is 164 mm from the antenna. However, for a complex integrated environment such as a mobile phone, this is not A strict boundary, depending on the situation.

Preferably, the connection guide 4 is located in a near field region of the wireless electronic device antenna, and a portion within a range of 20 mm from the antenna is a low conductivity connecting wire.

In the capacitive touch screen provided by the present embodiment, the portion 41 of the connecting wire 4 located in the near field region of the antenna is a low conductivity connecting wire. As described above, since the low conductivity connecting wire has the effect of reducing the intensity of the radio frequency signal transmitted by the wireless electronic device, when the radio frequency signal of the antenna is radiated to the vicinity of the connecting wire 4, the electromagnetic wave radiated to the inside of the connecting wire 4 can be reduced. The energy attenuates the intensity of the radio frequency signal conducted to the inside of the connecting wire 4, thereby reducing the interference of the radio frequency signal on the electrical signal received by the capacitive touch screen control circuit when the capacitive touch screen is applied in the wireless electronic device.

As shown in FIG. 4, in one embodiment of the present creation, The touch electrode in the touch button area 2 is an electrode with low conductivity, thereby further attenuating the phenomenon that the RF signal interferes with the electrical signal when the capacitive touch screen is applied in the wireless electronic device.

In still another embodiment of the present invention, the portion 42 of the connecting wire 4 located outside the near-field region of the antenna of the wireless electronic device is a high-conductivity connecting wire, and the resistance is small, thereby reducing the capacitive touch. When the screen is applied to a wireless electronic device, the RF signal causes interference to the electrical signal, and the capacitive touch screen channel resistance is within a suitable range to ensure the touch sensitivity of the capacitive touch screen. In this embodiment, preferably, the high conductivity connecting wire has a square resistance of less than 10 ohms/square. More preferably, the high conductivity connecting wire is a copper wire, a silver paste wire or a graphene wire.

It should be noted that, in this embodiment, the fabrication of the connecting wire 4 requires a two-step screen printing process or a yellow light process, and the connecting wire 4 is located at a portion 41 and a portion of the near-field region of the antenna radiation. The portion 42 of the connecting wire 4 located outside the near-field region of the antenna radiation can be electrically connected in the same layer, that is, the portion 41 of the connecting wire 4 located in the near-field region of the antenna and the connecting wire 4 are located The portion 42 outside the near-field region of the antenna radiation is electrically connected through its side, or may be overlapped, that is, the portion 41 in which the connecting wire 4 is located in the near-field region of the antenna and the connecting wire 4 are respectively located. The antenna radiates a portion 42 outside the near field region, and the portion 41 of the connecting wire 4 located in the near field region of the antenna and the portion 42 of the connecting wire 4 located outside the near field region of the antenna are partially overlapped. A portion 41 in which the connecting wire 4 is located in the near field region of the antenna radiation is realized And the connecting wire 4 is electrically connected to the portion 42 outside the near-field region of the antenna radiation; or may be a bridge connection, that is, the portion 41 of the connecting wire 4 located in the near-field region of the antenna radiation and The connecting wire 4 is located at a portion 42 outside the near-field region of the antenna, and then a cross-bridge is formed, so that the portion 41 of the connecting wire 4 located in the near-field region of the antenna and the connection are realized by a bridge. The electrical connection of the wire 4 to the portion 42 outside the near-field region of the antenna radiation is not limited in this context, as long as the connecting wire 4 is located in the portion 41 of the near-field region of the antenna and the connection. The wire 4 is located in the electrical connection of the portion 42 of the antenna radiating the near field region.

It should be noted that, in other embodiments of the present invention, the connecting wires 4 may also be fabricated by other processes, which is not limited in this creation.

As shown in FIG. 5, in still another embodiment of the present invention, the portion 42 of the connecting wire 4 located outside the near-field region of the antenna radiation is also a low-conductivity connecting wire, thereby further weakening the capacitive contact. When the control screen is applied to a wireless electronic device, the radio frequency signal causes interference to the electrical signal, and the connection wire 4 can be manufactured by one step of screen printing or yellow light process, and the process is relatively simple. In this embodiment, preferably, the low conductivity connecting wire has a square resistance greater than 10 ohms/square. More preferably, the low conductivity connecting wire is an indium tin oxide (ITO) wire or a nano silver wire. . It should be noted that, in other embodiments of the present invention, the connecting wires 4 may also be fabricated by other processes, which is not limited in this creation.

As shown in FIG. 6, in still another embodiment of the present invention, the shape of the trace of the connecting wire 4 located in the near field region of the antenna is curved, thereby avoiding the longest of the connecting wires 4 as much as possible. The line segment is the same as the polarization direction of the antenna, so that the direction of the electromagnetic wave generated by the driving signal and/or the sensing signal in the capacitive touch screen is different from the direction of the electromagnetic wave emitted by the antenna to transmit or receive the RF signal, thereby further weakening When the capacitive touch screen is applied to a wireless electronic device, the radio frequency signal causes interference to the electrical signal. Preferably, the curved shape is curved or wavy.

In another embodiment of the present invention, the shape of the trace of the connecting wire 4 located outside the near-field region of the antenna is also curved, thereby further reducing the application of the capacitive touch screen in the wireless electronic device. The phenomenon that the radio frequency signal causes interference to the electrical signal. Preferably, the curved shape is curved or wavy.

The capacitive touch screen provided by the present embodiment can significantly reduce the interference of the radio frequency signal of the wireless electronic device on the electrical signal of the capacitive touch screen when applied to the wireless electronic device, and the capacitive touch type There are no special requirements for the production process and control circuit of the screen, the process is simple, and the cost is low. In addition, the capacitive touch screen provided by the present embodiment further reduces or eliminates the need for capacitive touch screen control circuits, software, peripheral circuits, and the like to combat radio frequency signal interference, thereby further improving the capacitive touch type. Screen performance reduces production costs.

Exemplary device two:

The present creative embodiment provides a wireless electronic device, a package The capacitive touch screen, the antenna, and the radio frequency signal control circuit provided in any one of the foregoing exemplary embodiments, wherein the antenna is configured to receive and transmit a radio frequency signal, and the radio frequency signal control circuit includes a receiving end and a transmitting end, when the antenna is configured to receive a radio frequency signal, the receiving end is configured to receive a radio frequency signal received by the antenna, and when the antenna is used to transmit a radio frequency signal, the transmitting end is configured to transmit a radio frequency to the antenna signal. In one embodiment of the present invention, the wireless electronic device is preferably a mobile phone, a tablet computer, a wireless netbook or a notebook computer, but the present invention does not limit this, as long as the radio frequency signal is received in the wireless electronic device. And the sending device can be.

When the capacitive touch screen of any one of the exemplary devices is applied to a wireless electronic device, the phenomenon that the radio frequency signal interferes with the electrical signal can be significantly reduced, and the manufacturing process of the capacitive touch screen and The control circuit has no special requirements, and the process is simple and the cost is low. Therefore, the wireless electronic device provided in the embodiment of the present invention can significantly reduce the interference of the radio frequency signal on the electrical signal, and the process is simple and the cost is low.

Moreover, the creator also found that when the capacitive touch screen in the prior art is applied to a wireless electronic device, since the driving signal of the capacitive touch screen is a periodic square wave signal, correspondingly, the induced signal generated thereby It is also a periodic square wave signal, and the higher harmonic of the square wave signal flows through the connecting wire. Since the connecting wire is equivalent to one transmitting antenna, an alternating magnetic field is generated in the vicinity of the connecting wire, alternating The magnetic field in turn generates an alternating electric field, thus repeatedly forming electromagnetic waves radiating outward. therefore, When the frequency of the electromagnetic wave radiation generated by the higher harmonics in the electrical signal falls within the receiving frequency band of the radio frequency signal, when the antenna of the wireless electronic device receives and transmits to the radio frequency signal receiving end of the wireless electronic device, the radio frequency signal is interfered. receive.

The following is an analysis of the interference of the electrical signal of the capacitive touch screen to the reception of the radio frequency signal by analyzing the Fourier series of the periodic square wave signal function f(t). Any function f(t) with a normal period of T and a fundamental angular frequency of Ω can be decomposed into an algebraic sum of infinite sine and cosine functions, ie, a trigonometric function expanded into a Fourier series is:

Where the DC component a ₀ :

The amplitude of the cosine component a _n :

The amplitude of the sinusoidal component b _n :

Therefore, the periodic signal can be decomposed into a sum of a direct current component, a fundamental component, and a series of harmonic components.

For the periodic square wave signal shown in Figure 7, the f(t) function is expanded to the Fourier series:

It can be seen from equation (14) that the a ₀ and a _n of the Fourier series of the periodic square wave signal shown in Fig. 7 are zero, and there are no dc and cosine terms, only sinusoidal terms, that is, Is an odd function, in addition to the fundamental Ω, the spectrum also contains 3Ω, 5Ω, 7Ω... odd-numbered high-frequency harmonics. These high-frequency harmonics fall within the receiving frequency band of the RF signal and are received by the antenna of the wireless electronic device. When transmitted to the receiving end of the radio frequency signal, it may interfere with the reception of the radio frequency signal, and reduce the performance of the wireless electronic device when the capacitive touch screen is applied to the wireless electronic device.

In the wireless electronic device with the capacitive touch screen provided in the exemplary device 1 provided by the embodiment of the present invention, the connecting wire is located in a portion of the wireless electronic device where the antenna is radiated in the near field region is low. Conductivity connecting wires.

For the driving signal when the capacitive touch screen is working, according to the principle of reciprocity of the antenna, the connecting wire is equivalent to one transmitting antenna at this time. Since the driving signal is a periodic square wave signal, the current of the higher harmonics flows through the connecting wire and is transmitted through the connecting wire. When the frequency of the higher harmonic signal falls within the radio frequency receiving band of the wireless electronic device, It will interfere with the RF receiving signal, and the lower the conductivity ρ of the material, the larger the antenna resistance R _{ANT and the} lower the quality factor Q. Due to the reciprocity of the antenna, the lower the quality factor Q for the transmitting antenna, the worse the performance of the transmitting antenna transmitting the RF signal, thus reducing the effect of electromagnetic wave radiation, thereby reducing the electrical signal during operation of the capacitive touch screen. The interference with the RF received signal further improves the performance of the wireless electronic device with the capacitive touch screen.

Therefore, the wireless electronic device provided with the capacitive touch screen provided in the exemplary device 1 provided in the embodiment of the present invention can significantly reduce or eliminate mutual interference between the RF signal and the capacitive touch screen electrical signal, thereby improving the mutual interference. The performance of the wireless electronic device is simple, and the cost is low.

An exemplary verification one:

In order to accurately evaluate and quantify the mutual interference between RF signals and capacitive touch screen electrical signals, an implementation of this creation relies on Maxwell's electromagnetic equations to establish an accurate full-wave electromagnetic field model through the Finite Element Method (Finite Element Method). And the method of Moments is used to solve the problem. The capacitive touch screen and the conventional capacitive touch screen provided by the present embodiment are applied to the mobile phone as an example, and the capacitive touch provided by the present embodiment is provided. Contrast experiments were conducted when control screens and traditional capacitive touch screens were used in wireless electronics.

Referring to FIG. 1 , FIG. 3 , FIG. 8 and FIG. 9 , FIG. 1 is a connection wire 4 between the flexible circuit board 3 and the capacitive touch screen body 1 when the conventional capacitive touch screen is applied to a mobile phone. FIG. 3 is a schematic diagram of the connecting wires 4 (including 41 and 42) between the flexible circuit board 3 and the capacitive touch screen body in the capacitive touch screen provided by the creative embodiment, wherein 41 is The connecting wire 4 is located in a portion of the near-field region where the antenna radiates, and 42 is the connecting wire 4 located outside the near-field region of the antenna radiation. Part 8 is a schematic diagram showing a port distribution of a scattering model of the capacitive touch screen; and FIG. 9 is a partially enlarged schematic view showing a 埠 distribution of a scattering model of the capacitive touch screen. The 埠5 is located on the surface of the touch button area 2, usually the position of the main antenna of the mobile phone, and is used for analog RF signal radiation sources, and 埠301, 埠302, 埠303 are located at the pin positions of the capacitive touch screen control circuit. Wherein, the channel between the 埠 301 and the 埠 5 is in communication, the channel between the 埠 302 and the 埠 5 is the first channel adjacent to the right side of the 埠 301, and the channel between the 埠 303 and the 埠 5 is adjacent to the right side of the 埠 301 The second channel.

The finite element method is used to calculate the transmission coefficients of the 电容5 to 埠301, 埠302, and 埠303 in the conventional capacitive touch screen and the capacitive touch screen provided in one embodiment of the present invention. 10 to 15 are shown. 10 is a schematic diagram of a transmission coefficient frequency response curve of a channel between a 埠5 and a 埠301 in a conventional capacitive touch screen and a capacitive touch screen provided by the present embodiment, wherein O10 is The transmission coefficient frequency response curve diagram of the channel between 埠5 and 埠301 in the conventional capacitive touch screen, N10 is the transmission coefficient of the channel between 埠5 and 埠301 in the capacitive touch screen provided by the creative embodiment. Schematic diagram of the frequency response curve; Figure 11 shows the conventional capacitive touch screen and the capacitive touch screen provided by the present embodiment, when the RF signal sources are 900 MHz, 1.8 GHz, and 2.4 GHz, respectively. A comparison of the transmission coefficients of the channels to 埠301. Figure 12 is a diagram showing the transmission of a channel between 埠5 and 埠302 in a conventional capacitive touch screen and a capacitive touch screen provided in an embodiment of the present invention. Coefficient frequency response curve comparison diagram, wherein O12 is a transmission coefficient frequency response curve diagram of the channel between 埠5 and 埠302 in the conventional capacitive touch screen, and N12 is in the capacitive touch screen provided by the creative embodiment.传输5 to 埠302 channel transmission coefficient frequency response curve diagram; Figure 13 is the radio frequency signal source respectively 900MHZ, 1.8GHZ and 2.4GHZ, the traditional capacitive touch screen and this creation an implementation In the capacitive touch screen provided in the screen, the transmission coefficient comparison table of the channel between 埠5 and 埠302. FIG. 14 is a schematic diagram showing a comparison of transmission coefficient frequency response curves of a channel between 埠5 and 埠303 in a conventional capacitive touch screen and a capacitive touch screen provided in an embodiment of the present invention, wherein O14 is The transmission coefficient frequency response curve diagram of the channel between 埠5 and 埠303 in the conventional capacitive touch screen, N14 is the transmission coefficient of the channel between 埠5 and 埠303 in the capacitive touch screen provided by the creative embodiment. A schematic diagram of the frequency response curve; Figure 15 shows the conventional capacitive touch screen in the capacitive touch screen provided by the present embodiment, when the RF signal sources are 900 MHz, 1.8 GHz, and 2.4 GHz, respectively. A comparison of the transmission coefficients of the channels to 埠303.

From Fig. 10 and Fig. 11, it can be seen that compared with the conventional capacitive touch screen, the transmission coefficient of the channel between 埠5 and 埠301 is provided in the capacitive touch screen provided by the present embodiment. The transmission coefficient of the channel between 埠5 and 埠301 has about 40dB attenuation; from Fig. 12 and Fig. 13, it can be seen that compared with the conventional capacitive touch screen, 埠5 to 埠302 The transmission coefficient between the channels, in the capacitive touch screen provided by the present embodiment, the transmission between the channels 埠5 to 埠302 The transmission coefficient has an attenuation greater than 20 dB; from Fig. 14 and Fig. 15, it can be seen that the transmission coefficient of the channel between 埠5 and 埠303 is compared with the conventional capacitive touch screen. In the capacitive touch screen provided by the method, the transmission coefficient of the channel between 埠5 and 埠303 has an attenuation greater than 20 dB.

It can be seen that the transmission coefficient of the connecting wire between the capacitive touch screen and the capacitive touch screen control circuit in the conventional capacitive touch screen is different for the RF signal transmitted by the connecting wire. The transmission coefficient of the connecting wire between the capacitive touch screen body and the capacitive touch screen control circuit in the capacitive touch screen is greater than 20 dB, thereby reducing the RF signal to the capacitive touch screen electrical signal. interference.

When the analog mobile phone is in a high-power transmitting state, a strong electromagnetic field is generated. At 埠5 (ie, touch button region 2), a plane electromagnetic wave propagating along the Z-axis is introduced, and the direction of the electric field vector coincides with the direction of the electrode line, as shown in FIG. 16 is a schematic diagram of a 埠 distribution of the capacitive touch screen radiation model, wherein EMI is a plane electromagnetic wave transmitted in the Z-axis direction fed by 埠5, the frequency is 900 MHz, and the intensity is 1 V/m. Then, using the moment method to calculate the average electric field strength at the 埠301, 埠302, and 埠303 in the conventional capacitive touch screen and the capacitive touch screen provided by the present embodiment, as shown in FIG. 17 and 18, wherein, FIG. 17 is an average electric field intensity value at 埠301, 埠302, and 埠303 in a conventional capacitive touch screen, and FIG. 18 is a capacitive touch screen provided by the creative embodiment. Average electric field at 埠301, 埠302 and 埠303 Intensity values, as can be seen from Fig. 17 and Fig. 18, in the capacitive touch screen provided by the present embodiment, the RF electric field strength generated at 埠301, 埠302, and 埠303 is significantly smaller than that of the conventional capacitive touch. In the screen, the RF electric field strength generated at 埠301, 埠302, and 埠303.

As shown in Fig. 19 to Fig. 20, in Fig. 19, the metal sheet 6 is compared with the mobile phone antenna, and the 埠301 is fed with an RF signal having a frequency of 900 MHz and a power of 1 W, and FIG. 20 is a conventional capacitive touch. The screen and the capacitive touch screen provided by the present embodiment, the comparison table of the RF average electric field strength values generated by the electrical signals of the capacitive touch screen received by the metal piece 6 of the mobile phone antenna; It can be seen that the capacitive touch screen provided in the present embodiment has a large attenuation of the driving signal and/or the sensing signal of the capacitive touch screen, thereby reducing the electrical signal of the capacitive touch screen. Interference with RF signals.

In summary, the capacitive touch screen provided by the present embodiment and the wireless electronic device having the capacitive touch screen can significantly reduce the mutual interference between the RF signal and the electrical signal, and for the capacitive touch screen The manufacturing process and control circuit have no special requirements, the process is simple, and the cost is low.

Each part of this manual is described in a progressive manner. Each part focuses on the differences from other parts. The same similar parts between the parts can be referred to each other.

The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. More for these implementations The modifications may be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but the broadest scope consistent with the principles and novel features disclosed herein.

1‧‧‧electrode pattern area

2‧‧‧Touch button area

41‧‧‧The connecting wire is located in the near-field area of the antenna radiation

42‧‧‧Connected wires are located outside the near-field area of the antenna radiation

Claims (13)

A capacitive touch screen is applied to a wireless electronic device, comprising a capacitive touch screen body, a flexible circuit board, and a connecting wire connecting the capacitive touch screen body and the flexible circuit board, wherein the connecting wire is located at the The antenna of the wireless electronic device radiates a portion of the near field region that is a low conductivity connecting wire. The capacitive touch screen of claim 1, wherein the connecting wire is located in a near field region of the wireless electronic device antenna, and a portion within a range of 20 mm from the antenna is a low conductivity connecting wire. The capacitive touch screen of claim 1, wherein the connecting wire is located at a portion of the wireless electronic device that is outside the near-field region of the antenna radiation, and is a high-conductivity connecting wire. The capacitive touch screen of claim 3, wherein the high conductivity connecting wire has a square resistance of less than 10 ohms/square. The capacitive touch screen of claim 4, wherein the high conductivity connecting wire is a copper wire, a silver paste wire or a graphene wire. The capacitive touch screen of claim 1, wherein the connecting wire is located outside the near-field region of the antenna of the wireless electronic device and is a low-conductivity connecting wire. The capacitive touch screen of any one of claims 1 to 6, wherein the low conductivity connecting wire is an indium tin oxide wire or a nano silver wire. The capacitive touch screen of claim 1, wherein the capacitive touch screen body comprises an electrode pattern area and a touch button area, and the touch electrodes of the touch button area are electrodes of low conductivity. The capacitive touch screen of claim 1, wherein the connecting wire is in a curved shape in a portion of the near-field region of the antenna radiation. The capacitive touch screen of claim 9, wherein the connecting wire is located in a portion of the antenna radiating near the field portion and has a curved shape. The capacitive touch screen of claim 9 or 10, wherein the curved shape is curved or wavy. A wireless electronic device, comprising: the capacitive touch screen of any one of claims 1 to 11. The wireless electronic device of claim 12, wherein the wireless electronic device is a mobile phone, a tablet, a wireless netbook, or a notebook computer.