TWI588731B - Electronic device and the driving method thereof - Google Patents

Description

Electronic device and driving method thereof

The present invention relates to the technical field of touch detection, and more particularly to an electronic device that utilizes charge sharing for touch detection.

The technical principle of the touch panel is to detect the voltage, current, sound wave or infrared light according to different sensing methods when the finger or other medium touches the screen, and then measure the coordinate position of the touch pressure point. For example, the resistive touch panel uses the potential difference between the upper and lower electrodes to calculate the position of the pressure point to detect the touch point. A capacitive touch panel detects a change in capacitance from a generated current or voltage by utilizing a change in capacitance generated by electrostatic coupling between a transparent electrode arranged and a human body.

According to the principle of capacitive touch technology, it can be divided into two types: surface capacitive touch sensing (Surface Capacitive) and projected capacitive touch sensing (Projected Capacitive). Although the surface capacitive touch sensing technology architecture is simple in structure, it is difficult to achieve multi-touch and it is difficult to overcome the problems of electromagnetic interference (EMI) and noise, so that most of today's projected capacitive touch sensing technology development of.

Projected Capacitive technology can be divided into Self capacitance and Mutual capacitance. Self-inductive capacitive type refers to capacitive coupling between the touch object and the conductor line, and measures the capacitance of the conductor line. Change to determine the occurrence of a touch. The mutual-capacitance type is a capacitive coupling phenomenon that occurs between two adjacent conductor lines when a touch occurs.

The in-cell (InCell) manufacturing method can make the thickness of the display thinner and lighter, and become the mainstream technology of the current small and medium size touch display products. To extend the conventional touch technology to a large-size touch panel, the RC delay is increased due to the increase in size, which causes noise interference when the display panel is driven, which affects the touch effect. Therefore, there is still room for improvement in the conventional touch detection technology.

The object of the present invention is mainly to provide an electronic device in which the electronic device utilizes charge sharing to detect whether there is a touch or proximity of a foreign object.

According to a feature of the present invention, an electronic device includes a first scan line, a second scan line, a first data line, a sensing line, a first transistor, a pixel, and a second A transistor, a charge and discharge device. The first transistor is connected to the first scan line and the first data line. The pixel has a pixel electrode connected to the first transistor. The second transistor is coupled to the first scan line, a common electrode of the pixel, and the sense line. The charge and discharge device is coupled to the second transistor, the second scan line, and the sense line; wherein when the first scan line is at a high potential, the charge and discharge device is charged when the second scan line is high At the potential, the sensing line senses the current of the charging and discharging device to determine whether there is a touch or proximity of the foreign object.

According to another feature of the present invention, the present invention provides a driving method for an electronic device, the electronic device having a first scan line, a second scan line, a first data line, a sensing line, and a charge and discharge device. a charge and discharge device coupled to the second scan line, the first a data line and the sensing line, the driving method drives the first scanning line to be high at a first time interval to enable the charging and discharging device to be charged; and drive the second scanning at a second time interval The line is high, so that the sensing line senses the current of the charging and discharging device, thereby determining whether there is a touch or proximity of the foreign object.

100‧‧‧Electronic devices

110‧‧‧First scan line

120‧‧‧second scan line

130‧‧‧First data line

140‧‧‧Sensing line

M1‧‧‧first transistor

150‧‧ ‧ pixels

M2‧‧‧second transistor

160‧‧‧Charge and discharge device

M3‧‧‧ third transistor

M4‧‧‧ fourth transistor

M5‧‧‧ fifth transistor

170‧‧‧DC blocking capacitor

G‧‧‧ gate

D‧‧‧汲

S‧‧‧ source

151‧‧‧pixel electrode

153‧‧‧Common electrode

161‧‧‧ first end

163‧‧‧ second end

190‧‧‧Operational Amplifier

180‧‧‧ equivalent capacitance

1500‧‧‧Handheld device

1510‧‧‧display screen

1511‧‧‧Area

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view showing an electronic device of the present invention.

2 is a schematic view showing the operation of the electronic device of the present invention.

3 is a circuit diagram of an electronic device of the present invention.

4 and 5 are schematic diagrams showing the operation of the electronic device of FIG.

6, FIG. 7, and FIG. 8 are schematic diagrams of the simulation of the electronic device of FIG.

FIG. 9 is a schematic diagram showing whether the present invention has a touch or proximity of a foreign object under different capacitance values.

Figure 10 is another circuit diagram of the electronic device of the present invention.

11 and 12 are schematic diagrams of the simulation of the electronic device of FIG.

Figure 13 is a schematic diagram showing the simulation of the current sensed by the sensing line when there is a touch and no touch.

14 is a flow chart of a driving method of an electronic device according to the present invention.

Figure 15 is a schematic view showing the use of an electronic device of the present invention.

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood here The specific embodiments described are merely illustrative of the invention and are not intended to limit the invention.

FIG. 1 is a schematic view showing an electronic device 100 of the present invention. The electronic device 100 includes a first scan line 110, a second scan line 120, a first data line 130, a sensing line 140, a first transistor M1, a pixel 150, a second transistor M2, and a Charge and discharge device 160. In an embodiment of the invention, the electronic device 100 may be a touch display panel.

The first transistor M1 is connected to the first scan line 110 and the first data line 130. The pixel 150 has a pixel electrode 151 connected to the first transistor M1. The second transistor M2 is connected to the first scan line 110 , a common electrode 153 of the pixel 150 , and the sensing line 140 . The charge and discharge device 160 is coupled to the second transistor M2, the second scan line 120, and the sense line 140.

When the first scan line 110 is at a high potential, the charge and discharge device 160 is charged. When the second scan line 120 is at a high potential, the sense line 140 senses the current of the charge and discharge device 160 to determine Is there a touch or proximity of the foreign object? The sensing line 140 is coupled to an operational amplifier 190 to convert the current of the charging and discharging device 160 into a touch sensing voltage for subsequent touch detection.

2 is a schematic diagram of the operation of the electronic device 100 of the present invention. As shown in FIG. 2, when the external object touches or approaches the electronic device 100, a capacitive effect is generated, that is, an equivalent capacitance 180 generated by the touch or proximity of the foreign object is connected in parallel with the charging and discharging device 160. The equivalent capacitor 180 is not an actual capacitor, which is a capacitive effect generated when a foreign object is touched or is in close proximity to the electronic device 100. The charge-discharge device 160 generates a charge sharing effect by the equivalent capacitance 180 generated by the touch or proximity of the foreign object.

Due to the charge sharing effect, when there is a touch or proximity of the foreign object, The sensing line 140 senses that the current of the charging and discharging device 160 is smaller than the current of the charging and discharging device 160 when there is no touch or proximity of the foreign object. In this way, it is possible to detect whether there is a touch or proximity of the foreign object. In FIG. 2, the dimensions of the actual components are not shown, but are merely for explaining the operation of the electronic device 100.

3 is a circuit diagram of an electronic device 100 of the present invention. As shown in FIG. 3, the electronic device 100 includes a first scan line 110, a second scan line 120, a first data line 130, a sensing line 140, a first transistor M1, a pixel 150, and a first The second transistor M2, a charge and discharge device 160, a third transistor M3, a fourth transistor M4, a fifth transistor M5, and a DC blocking capacitor 170. The first to fifth transistors M1 to M5 may be Low Temperature Poly-silicon (LTPS) transistors, Indium Gallium Zinc Oxide (IGZO) transistors, or amorphous germanium (a-Si). ) A transistor.

The gate g of the first transistor M1 is connected to the first scan line 110, the drain d is connected to the first data line 130, and the source s is connected to the pixel electrode 151 of the pixel 150. The gate g of the second transistor M2 is connected to the first scan line 110, the drain d is connected to the sensing line 140, and the source s is connected to the common electrode 153 of the pixel. The charge and discharge device 160 is A capacitor.

The gate g and the drain d of the third transistor M3 are connected to the first scan line 110, and the source s is connected to a first end 161 of the charge and discharge device 160. The gate g of the fourth transistor M4 is connected to the second scan line 120, the drain d is connected to the common electrode 153 of the pixel 150, and the source s is connected to the first end of the charging and discharging device 160. 161. a gate g of the fifth transistor M5 is connected to the first end 161 of the charging and discharging device 160, The drain d is connected to the sensing line 140, and the source s is connected to a second end 163 of the charging and discharging device 160. The first end of the DC blocking capacitor 170 is connected to the second end 163 of the charging and discharging device 160, and a second end thereof is connected to the second scanning line 120.

4 and 5 are schematic diagrams showing the operation of the electronic device 100 of FIG. As shown in FIG. 4, when the first scan line 110 is at a high potential and the second scan line 120 is at a low potential, the first transistor M1, the second transistor M2, and the third transistor M3 are Turning on, the voltage on the first data line 130 charges the charge and discharge device 160, and the charge and discharge device 160 stores the high potential. The voltage on the sensing line 140 is transferred to the common electrode 153 via the second transistor M2.

As shown in FIG. 5, when the second scan line 120 is at a high potential and the first scan line 110 is at a low potential, the first transistor M1, the second transistor M2, and the third transistor M3 are turned off. The fourth transistor M4 and the fifth transistor M5 are turned on, and the equivalent capacitance 180 generated by the charging/discharging device 160 and the touch or proximity of the foreign object generates a charge sharing effect. At the same time, the current of the charging and discharging device 160 is transmitted to the sensing line 140 via the fifth transistor M5.

Due to the charge sharing effect, when there is a touch or proximity of the foreign object, the sensing line 140 senses that the current of the charging and discharging device 160 is smaller than the current of the charging and discharging device 160 when there is no touch or proximity of the foreign object. In this way, it is possible to detect whether there is a touch or proximity of the foreign object. The DC blocking capacitor 170 can cut off the DC leakage current, so that the voltage of the sensing line 140 can be increased to a normal common voltage (VCom), and only the signal of the second scanning line 120 is sensed to be switched from a low potential to a high level. The transient current at the potential and the reduction in power consumption of the entire touch system.

6, FIG. 7, and FIG. 8 are schematic diagrams of the simulation of the electronic device 100 of FIG. It simulates the voltage and sense current of the relevant node of the electronic device 100. 6 is a schematic diagram showing the voltage vgate 1 in of the first scan line 110, the voltage vgate 2 in of the second scan line 120, and the voltage vgate 3 in on a third scan line. Figure 7 is a diagram showing the voltage of each node when there is a touch and no touch. Here, VPreset in FIG. 7 represents the voltage of the node Preset in FIG. 3, VPixel in FIG. 7 represents the voltage of the pixel electrode 151 in FIG. 3, and Vcom in FIG. 7 represents the voltage of the common electrode 153 in FIG. FIG. 8 is a schematic diagram showing the simulation of the current sensed by the sensing line 140 when there is a touch and no touch. From the foregoing simulation results, it can be found that the present invention can successfully detect whether there is a touch or proximity of a foreign object through the technique of charge sharing.

FIG. 9 is a schematic diagram showing whether the present invention has a touch or proximity of a foreign object under different capacitance values. For the simulation analysis of different equivalent capacitors 180, it is discussed for the touch capacitance of three different foreign objects or the equivalent capacitance 180 generated when the proximity is made. Example A: equivalent capacitance 180 is 10fF, charge and discharge device 160 is 5fF; example B: equivalent capacitance 180 is 20fF, charge and discharge device 160 is 10fF; example C: equivalent capacitance 180 is 30fF, charge and discharge device 160 It is 20fF. The difference between the sense currents of the touch and the touch can be obtained from the current simulation result, and the difference can be amplified and read by the operational amplifier 190 and an integrator (not shown). Further, the simulation results of three different touch capacitance conditions are organized into FIG.

It can be seen from the results of FIG. 9 that the electronic device 100 of the present invention can distinguish the difference between the touch and the touch, and the equivalent capacitance 180 generated when the foreign object in the electronic device 100 is touched or connected can be as small as 10 fF. level.

FIG. 10 is another circuit diagram of the electronic device 100 of the present invention. As shown in FIG. 10, the electronic device 100 includes a first scan line 110, a second scan line 120, and a first A data line 130, a sensing line 140, a first transistor M1, a pixel 150, a second transistor M2, a charge and discharge device 160, a third transistor M3 and a fourth transistor M4. The first to fourth transistors M1 to M4 are low temperature polycrystalline germanium (LTPS) transistors, indium gallium zinc oxide (IGZO) transistors, or amorphous germanium (a-Si) transistors.

The gate g of the third transistor M3 is connected to the first end 161 of the charging and discharging device 160 and a common electrode 153, and the drain d is connected to the sensing line 140. The gate g of the fourth transistor M4 is connected to the second scan line 120, the drain d is connected to a source s of the third transistor M3, and the source s is connected to the second scan line 140.

When the first scan line 110 is at a high potential, the first transistor M1 and the second transistor M2 are turned on, and a voltage (Vsense) on the sensing line 140 is transmitted to the common electrode via the second transistor M2. 153 (common electrode), and charging the charging and discharging device 160 to a high potential. When the second scan line 120 is at a high potential, the first transistor M1 and the second transistor M2 are turned off, and the third transistor M3 and the fourth transistor M4 are turned on, and the charge and discharge device 160 and the foreign object The equivalent capacitance 180 generated by the touch or proximity generates a charge sharing effect, and the current of the charging and discharging device 160 is transmitted to the sensing line 140 via the third transistor M3.

As shown in FIG. 10, the main difference between the electronic device 100 and the electronic device 100 of FIG. 3 is that the electronic device 100 of FIG. 10 is a circuit design of 4T1C, and one circuit is smaller than the circuit design of the electronic device 10 of FIG. The rate is higher. The purpose of the fourth transistor M4 is to form a large resistance as a diode function to prevent a current (Isense) on the sensing line 140 from flowing to the fourth transistor M through the third transistor M3. , The signal current is decreased, so that the sense terminal voltage can be raised to a normal common voltage (VCom), and only the transient current when the signal of the second scan line 140 is switched from a low potential to a high potential can be sensed. To achieve the accuracy of the entire touch system.

11 and 12 are schematic diagrams of the simulation of the electronic device 100 of FIG. It simulates the voltage and sense current of the relevant node of the electronic device 100. Fig. 11 is a view showing the voltage of the common electrode 153 and the voltage of the pixel electrode 151 when there is a touch and no touch. From the simulation results of FIG. 11, it can be found that the present invention can successfully detect whether there is a touch or a close contact of a foreign object through the technique of charge sharing. Fig. 12 is a view showing the voltage (VPixel) of the pixel electrode 151 minus the voltage (Vcom) of the common electrode 153 when there is a touch and no touch. The voltage of the pixel electrode 151 minus the voltage of the common electrode 153 indicates the voltage applied to the pixel 150, that is, the operating voltage of the liquid crystal. It can be seen from the liquid crystal voltage sustaining signal simulation result of FIG. 12 that the operating voltage of the liquid crystal can be maintained above a certain voltage, that is, the technology of the present invention enables normal operation of the liquid crystal regardless of whether a foreign object touches or is in close proximity.

FIG. 13 is a schematic diagram showing the simulation of the current sensed by the sensing line 140 in the presence and absence of a touch. As shown in FIG. 13, when there is a touch, the current difference sensed by the sensing line 140 is as shown by the ellipse B, and the current difference sensed by the sensing line 140 when there is no touch is as shown by the ellipse A. As can be seen from FIG. 13, the current difference sensed by the sensing line 140 when touched and not touched is about 2 [mu]A. It can be easily separated by the operational amplifier 190 whether there is a touch or no touch. That is to say, the technology of the present case can easily detect the touch or proximity of the foreign object.

14 is a flow chart of a driving method of an electronic device 100 according to the present invention. As shown in FIG. 1 , the electronic device 100 has a first scan line 110 , a second scan line 120 , a first data line 130 , a sensing line 140 , and a charge and discharge device 160 . The charge The discharge device 160 is coupled to the first scan line 110, the second scan line 130, the first data line 130, and the sense line 140. The driving method is first driven in a first time interval in step (A). The first scan line 110 is at a high potential to cause the charge and discharge device 160 to be charged. In the step (B), the second scan line 120 is driven to a high potential at a second time interval, so that the sensing line 140 senses the current of the charging and discharging device 160, thereby determining whether there is a foreign object touch. Touch or close.

Touch or proximity of foreign objects creates a capacitive effect. The charge-discharge device 160 generates a charge sharing effect by the equivalent capacitance 180 generated by the touch or proximity of the foreign object. When there is a touch or proximity of the foreign object, the sensing line 140 senses that the current of the charging and discharging device 160 is smaller than the current of the charging and discharging device 160 when there is no touch or proximity of the foreign object.

Figure 15 is a schematic illustration of the use of an electronic device 100 in accordance with one embodiment of the present invention. This implementation may be a handheld device 1500 such as a cell phone. As can be seen from the foregoing description, the electronic device 100 of the present invention can coexist with the pixels of the display device, and thus can be applied to a display screen 1510 of the handheld device 1500. In the entire display screen 1510, an electronic device 100 of the embodiment of the present invention is disposed in the X direction and the Y direction, for example, every 100 pixels, so that a foreign object touch can be provided in the entire display screen 1510 or Proximity detection function. In the X direction and the Y direction, the electronic device 100 of the embodiment of the present invention is disposed every other number of pixels, which may be determined according to the resolution of the required touch detection, which is disclosed by the technical person in accordance with the present invention. Can be completed, no longer repeat them.

In other embodiments, the electronic device 100 of the embodiment of the present invention is applied to an area 1511 of the display screen 1510 of FIG. In this region 1511, one electronic device 100 of the present invention is provided every other pixel in the X direction and the Y direction. Generally, the fingerprint ridge has an effective width of about 200 μm to 300 μm. The size of one display pixel is about 5 μm. Therefore, every other pixel, that is, when the electronic device 100 of the embodiment of the present invention is disposed, the sensing image of the fingerprint can be effectively detected and correctly obtained. Therefore, the function of fingerprint detection can be provided in the area 1511 of the display screen 1510. There is no need to additionally set a fingerprint detection button, which can effectively increase the display area of the handheld device 1500.

The electronic device of this case is designed by using five thin film transistors and one capacitor or four thin film transistors and one capacitor. When applied to an in-cell touch panel, the process of the display panel can be used in the process of the thin film transistor and the capacitor, and the in-cell (In Cell) touch technology is maintained, and the advantage of the display panel being light and thin can be maintained. At the same time, the capacitance of the electronic device 100 and the capacitance of the finger can be used for charge sharing to detect whether there is a finger touch or proximity on the display panel. This case uses the concept of charge sharing to easily solve the problem of resistance and capacitance delay (RC Delay) faced by traditional large-size touch panels, and can easily realize a thin, low-energy, low-cost touch display. In another embodiment of the present invention, the electronic device that provides the fingerprint detection function can simultaneously display and provide fingerprint detection, which can effectively increase the display area of the handheld device.

The above-mentioned embodiments are merely examples for convenience of description, and the scope of the claims is intended to be limited to the above embodiments.

100‧‧‧Electronic devices

110‧‧‧First scan line

120‧‧‧second scan line

130‧‧‧First data line

140‧‧‧Sensing line

M1‧‧‧first transistor

150‧‧ ‧ pixels

M2‧‧‧second transistor

160‧‧‧Charge and discharge device

M3‧‧‧ third transistor

M4‧‧‧ fourth transistor

M5‧‧‧ fifth transistor

170‧‧‧DC blocking capacitor

G‧‧‧ gate

D‧‧‧汲

S‧‧‧ source

151‧‧‧pixel electrode

153‧‧‧Common electrode

161‧‧‧ first end

163‧‧‧ second end

190‧‧‧Operational Amplifier

Claims (15)

An electronic device comprising: a first scan line and a second scan line; a first data line; a sensing line; a first transistor connected to the first scan line and the first data line; a pixel having a pixel electrode connected to the first transistor; a second transistor connected to the first scan line, a common electrode of the pixel and the sensing line; and a charge and discharge device coupled to the second a transistor, the second scan line, and the sensing line; wherein, when the first scan line is at a high potential, the charge and discharge device is charged, and when the second scan line is at a high potential, the sense line senses the The current of the charging and discharging device to determine whether there is a touch or proximity of the foreign object. The electronic device of claim 1, wherein the touch or proximity of the foreign object generates a capacitive effect, and the charge and discharge device generates a charge by an equivalent capacitance generated by the touch or proximity of the foreign object. Sharing effect. The electronic device of claim 2, wherein when the foreign object touches or is in proximity, the sensing line senses that the current of the charging and discharging device is less than when there is no touch or proximity of the foreign object. The current of the charge and discharge device. The electronic device of claim 3, wherein the gate of the first transistor is connected to the first scan line, the drain of the first transistor is connected to the first data line, and the source thereof is connected to the pixel. The pixel electrode, the gate of the second transistor is connected to the first scan a line, the drain of which is connected to the sensing line, the source of which is connected to the common electrode of the pixel, and the charging and discharging device is a capacitor. The electronic device of claim 4, further comprising: a third transistor having a gate and a drain connected to the first scan line, and a source connected to the first of the charge and discharge device a fourth transistor having a gate connected to the second scan line, a drain connected to the common electrode of the pixel, a source connected to the first end of the charge and discharge device, and a fifth electrode a crystal having a gate connected to the first end of the charging and discharging device, a drain connected to the sensing line, a source connected to a second end of the charging and discharging device, and a DC blocking capacitor, the first The end is connected to the second end of the charging and discharging device, and a second end thereof is connected to the second scanning line. The electronic device of claim 5, wherein when the first scan line is at a high potential, the first transistor, the second transistor, and the third transistor are turned on, the first data The voltage on the line charges the charge and discharge device, and the voltage on the sense line is transmitted to the common electrode via the second transistor. The electronic device of claim 6, wherein when the second scan line is at a high potential, the first transistor, the second transistor, and the third transistor are turned off, the fourth device The crystal and the fifth transistor are turned on, and the equivalent capacitance generated by the charging or discharging device and the contact or proximity of the foreign object generates a charge sharing effect, and the current of the charging and discharging device is transmitted to the current through the fifth transistor. Sensing line. The electronic device of claim 5, wherein the first to fifth electro-crystalline systems are low-temperature polycrystalline germanium transistors, indium gallium zinc oxide crystals, or amorphous germanium transistors. The electronic device of claim 4, further comprising: a third transistor having a gate connected to the first end of the charge and discharge device and the common electrode, the drain of which is connected to the sensing line; and a fourth transistor whose gate is connected to the second scan a drain having a drain connected to a source of the third transistor and a source connected to the second scan line; wherein a second end of the charge and discharge device is coupled to the second scan line. The electronic device of claim 9, wherein when the first scan line is at a high potential, the first transistor and the second transistor are turned on, and the voltage on the sense line is via the second The crystal is transferred to the common electrode, and the charging and discharging device is charged. The electronic device of claim 10, wherein when the second scan line is at a high potential, the first transistor and the second transistor are turned off, and the third transistor and the fourth transistor are Turning on, the charge and discharge device generates a charge sharing effect by the equivalent capacitance generated by the touch or proximity of the foreign object, and the current of the charge and discharge device is transmitted to the sensing line via the third transistor. The electronic device of claim 9, wherein the first to fourth electro-crystalline systems are low-temperature polycrystalline germanium transistors, indium gallium zinc oxide crystals, or amorphous germanium transistors. A driving method of an electronic device, the electronic device having a first scanning line, a second scanning line, a sensing line and a charging and discharging device, the charging and discharging device being coupled to the second scanning line and the sensing line, the driving The method includes: driving the first scan line to a high potential and the second scan line to a low potential at a first time interval to enable the charge and discharge device to be charged; And driving the second scan line to a high potential and the first scan line to be low, so that the sensing line senses the current of the charging and discharging device, thereby determining whether there is a foreign object touch Or close proximity. The driving method of the electronic device according to claim 13, wherein the touch or proximity of the foreign object generates a capacitive effect, and the equivalent capacitance generated by the charging or discharging device and the external object touch or proximity Produces a charge sharing effect. The driving method of the electronic device according to claim 14, wherein when the foreign object touches or is in proximity, the sensing line senses that the current of the charging and discharging device is smaller than a touch without the foreign object or The current of the charge and discharge device when it is in close proximity.