TW202024874A - Touch control display device - Google Patents

Abstract

A touch control display device includes a pixel array, a light filtering layer, a shielding layer, a first resistor and a touch sensing layer. The pixel array includes a plurality of display pixels. The light filtering layer covers the pixel array. The light filtering layer has a first side and a second side which are opposite. The shielding layer disposed on the first side or the second side of the light filtering layer. A first end of the first resistor is coupled to the shielding layer and a second end of the first resistor receives a reference voltage. The touch sensing layer covers on the first surface of the shielding layer.

Description

Touch display

The invention relates to a touch display, and more particularly to a touch display capable of reducing touch noise.

With the popularization of electronic products, touch display panels with multi-functional man-machine interfaces have become important accessories for electronic products. In the development of multi-functional touch display panels, integrated finger touch sensing functions have become standard equipment, and active pen writing technology has become increasingly mature and has gradually become a necessary tool for high-end electronic devices.

In today's technology, active pens are particularly susceptible to external noise interference. In addition, the active pen also has special requirements for the noise generated on the touch display panel of the matched application. In the conventional technical field, the electrical signals in the pixel array will generate periodic voltage swings and generate fixed noise. These noises are transmitted to the touch sensing layer through the coupling effect of the parasitic capacitance in the touch display. As a result, the accuracy of touch sensing produced by the touch sensing array will be greatly compromised, affecting overall performance.

The invention provides a touch display, which can effectively reduce the real noise interference of touch.

The touch display of the present invention includes a pixel array, a filter substrate, a shielding layer, a first resistor, and a touch sensing layer. The pixel array has multiple display pixels. The filter substrate covers the pixel array. The filter substrate has a first surface and a second surface opposite to each other. The shielding layer is disposed on the first surface or the second surface of the filter substrate. The first terminal of the first resistor is coupled to the shielding layer, and the second terminal of the first resistor receives the reference voltage. The touch sensing layer covers the first surface of the filter substrate.

In an embodiment of the present invention, the above-mentioned reference voltage is a ground voltage.

In an embodiment of the present invention, the touch display further includes a second resistor. The first end of the second resistor is coupled to the second end of the first resistor, and the second end of the second resistor receives the ground voltage.

In an embodiment of the present invention, the resistance value of the first resistor is not greater than the resistance value of the second resistor.

In an embodiment of the present invention, the touch display further includes a touch sensing controller. The touch sensing controller is coupled to the touch sensing layer, the shielding layer and the first end of the first resistor.

In an embodiment of the present invention, the aforementioned touch sensing controller receives the touch signal on the touch sensing layer and the reference signal on the first end of the first resistor. The touch sensing controller uses the touch signal and the reference signal as a differential signal pair to perform signal processing actions.

In an embodiment of the present invention, the aforementioned shielding layer is a transparent conductive film layer.

In an embodiment of the present invention, the first surface of the aforementioned filter substrate is the outer surface of the filter substrate, and the second surface of the filter substrate is the inner surface of the filter substrate.

In an embodiment of the present invention, the above-mentioned filter substrate is a color filter substrate.

Based on the above, the present invention receives the reference voltage through the resistor through the shielding layer overlapping the filter substrates. By means of parasitic capacitive coupling, the touch signal on the touch sensing layer and the reference signal on the shielding layer can carry common mode noise. Therefore, through the processing method of the differential signal pair, the noise on the touch signal can be reduced, and the accuracy of touch sensing can be improved.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail in conjunction with the accompanying drawings.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of a touch display according to an embodiment of the present invention. 1 is a cross-sectional view of the touch display 100. The touch display 100 includes a pixel array 110, a filter substrate 120, a shielding layer 130, a resistor R1, and a touch sensing layer 140. The pixel array 110 has a plurality of display pixels, wires connecting the display pixels, and peripheral circuits (not shown). The filter substrate 120 covers the pixel array 110 and is not in contact with the pixel array 110. The filter substrate 120 has a first surface S1 and a second surface S2 opposite to each other. In this embodiment, the second surface S2 of the filter substrate 120 faces the pixel array 110. In addition, the filter substrate 120 and the pixel array 110 have a parasitic capacitance CP2.

In this embodiment, the shielding layer 130 is disposed on the first surface S1 of the filter substrate 120 and is in contact with the first surface S1 of the filter substrate 120. The shielding layer 130 may be formed of a transparent wire material, such as indium tin oxide (ITO), or other similar materials well known to those skilled in the art. In this embodiment, the shielding layer 130 may also be a transparent conductive film layer (out cell shielding layer) outside the display array 110. It is worth noting that the shielding layer 130 is coupled to the first end of the resistor R1, and the second end of the resistor R1 receives the reference voltage VB. In other words, the shielding layer 130 can receive the reference voltage VB through the resistor R1.

On the other hand, the touch sensing layer 140 covers the shielding layer 130 and the filter substrate 120, and the first surface S1 of the filter substrate 120 faces the touch sensing layer 140. The touch sensing layer 140 is not in contact with the shielding layer 130 and the filter substrate 120, and has a parasitic capacitance CP1.

In this embodiment, the touch sensing layer 140 serves as the active surface of the touch sensing action, and the shielding layer 130 serves as the reference surface of the touch sensing action. When the touch display 100 is working, the noise generated on the display array 110 will be transmitted to the shielding layer 130 through the coupling effect of the parasitic capacitance CP2. Therefore, as the reference surface of the touch sensing action, the aforementioned noise will be carried. In addition, through the parasitic capacitance CP1, the aforementioned noise will also be coupled to the touch sensing layer 140. That is to say, the aforementioned noise, the touch signal generated on the touch display 100 and the reference signal on the shielding layer 130 will form a common mode noise. Therefore, in the implementation of the present invention, the touch display 100 only needs to subtract the touch signal generated on the touch display 100 and the reference signal on the shielding layer 130 to reduce the energy of the noise on the touch signal.

In this embodiment, the reference voltage VB may be a ground voltage of 0 volts, or the reference voltage VB may also be a positive voltage or a negative voltage that is not 0 volts.

Please note here that in this embodiment, the shielding layer 130 may also be disposed on the second surface S2 of the filter substrate 120 and in contact with the second surface S2.

In addition, the filter substrate 120 of this embodiment is a color filter substrate, and the pixel array 110 may include a multiplexer and a shift register circuit. Both the filter substrate 120 and the pixel array 110 can be implemented using a structure well known to those skilled in the art, and there is no specific limitation.

Please refer to FIG. 2 below. FIG. 2 is a schematic diagram of a touch display according to another embodiment of the present invention. The touch display 200 includes a pixel array 210, a filter substrate 220, a shielding layer 230, a resistor R1, a touch sensing layer 240, and a touch sensing controller 250. Different from the previous embodiment, the touch sensing controller 250 in this embodiment is coupled to the touch sensing layer 240 and the first end of the resistor R1, and is connected to the touch sensing layer 240 and the first end of the resistor R1, respectively. One end receives the touch signal DS1 and the reference signal REF1. The touch sensing controller 250 also makes the touch signal DS1 and the reference signal REF1 a differential signal pair, and processes the touch signal DS1 and the reference signal REF1, for example, through a differential amplifier, to generate a touch result DSOUT.

Please refer to FIG. 2 and FIG. 3 simultaneously. FIG. 3 is a schematic diagram of a signal waveform of a touch sensing operation according to an embodiment of the present invention. In FIG. 3, the display array 210 receives a periodically switching signal CS1 during operation. The rising and falling edges of signal CS1 will generate corresponding noise. These noises are coupled to the sensing signal DS1 and the reference signal REF1 through the parasitic capacitance CP1 and/or CP2.

It can be clearly found from FIG. 3 that, based on the same source of noise, the noise (part of the glitch) carried on the sensing signal DS1 and the reference signal REF1 have substantially the same phase. Therefore, by using the operator OP1 to subtract the sensing signal DS1 and the reference signal REF1, the voltage amplitude of the noise on the generated sensing signal DSOUT can be significantly reduced.

Next, please refer to FIG. 4. Regarding the implementation details of the aforementioned operator OP1, reference may be made to the implementation of the touch sensing controller according to the embodiment of the present invention shown in FIG. 4. A differential amplifier DA1 can be provided in the touch sensing controller to realize the operator OP1. The two input terminals of the differential amplifier DA1 can respectively receive the sensing signal DS1 and the reference signal REF1, and by eliminating the common mode noise in the sensing signal DS1 and the reference signal REF1, and generating the touch result DSOUT.

Please refer to FIGS. 5A and 5B below. FIGS. 5A and 5B respectively show a schematic diagram of a touch display according to another embodiment of the present invention and a diagram of the relationship between its resistance value and the noise level. In FIG. 5A, the touch display 500 includes a pixel array 510, a filter substrate 520, a shielding layer 530, a resistor R1, and a touch sensing layer 540. The shielding layer 530 covers the outer surface (first surface S1) of the filter substrate 520, and the filter substrate 520 covers the pixel array 510. The touch sensing layer 540 covers the outer surface of the filter substrate 520, and the touch sensing layer 540 covers between the filter substrates 520 and has a parasitic capacitance CP1.

It is worth noting that in this embodiment, the shielding layer 530 is coupled to the first end of the resistor R1, and the second end of the resistor R1 receives the ground voltage GND as a reference voltage. In addition, by adjusting the resistance value of the resistor R1, the voltage peak of the noise on the touch result can be controlled. Among them, in this embodiment, in FIG. 5B, the larger the resistance value of the resistor R1, the lower the voltage peak value of the noise on the touch result.

Please refer to FIGS. 6A and 6B below. FIGS. 6A and 6B respectively show a schematic diagram of a touch display according to another embodiment of the present invention and a diagram of the relationship between its resistance value and the noise level. In FIG. 6A, the touch display 600 includes a pixel array 610, a filter substrate 620, a shielding layer 630, resistors R1, R2, and a touch sensing layer 640. The shielding layer 630 covers the inner surface (the second surface S2) of the filter substrate 620, and the filter substrate 620 covers the pixel array 610. The touch sensing layer 640 covers the outer surface of the filter substrate 620, and the touch sensing layer 640 covers between the filter substrates 620 and has a parasitic capacitance CP1. In this embodiment, the shielding layer 630 also receives the common voltage VCOM.

It is worth noting that, in this embodiment, the shielding layer 630 is coupled to the first end of the resistor R1, and the second end of the resistor R1 receives the reference voltage VB. Furthermore, the second end of the resistor R1 is further coupled to the first end of the resistor R2, and the second end of the resistor R2 receives the ground voltage. Here, the voltage value of the reference voltage VB can be determined according to the ratio of the resistors R1 and R2. In addition, by adjusting the resistance values of the resistors R1 and R2, the voltage peak of the noise on the touch result can be controlled. Among them, in this embodiment, in FIG. 6B, the larger the resistance value of the resistor R2, the lower the voltage peak value of the noise on the touch result. Correspondingly, if the resistance value of the resistor R1 is smaller, the touch The voltage peak of the noise on the control result is lower. Therefore, in the embodiment of the present invention, to make the touch result have a relatively small resistance value, the resistance value of the resistor R1 can be made not greater than the resistance value of the resistor R2.

In summary, in the present invention, the shielding layer is coupled to the reference voltage through a resistor. In this way, the noise generated during the operation of the display array can be coupled to the shielding layer and the touch sensing layer. By subtracting the reference signal and the touch signal on the shielding layer and the touch sensing layer, the voltage peak of the noise on the touch signal can be effectively reduced, and the working performance of the touch display can be effectively improved.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention shall be subject to those defined by the attached patent scope.

100, 200, 500, 600: touch display 110, 210, 510, 610: pixel array 120, 220, 520, 620: filter substrate 130, 230, 530, 640: shielding layer R1, R2: resistance 250: Touch sensing controller 140, 240, 540, 640: touch sensing layer S1: first surface S2: second surface CP1, CP2: parasitic capacitance VB: reference voltage GND: ground voltage DS1: touch signal REF1: Reference signal DSOUT: touch result VCOM: common voltage DA1: differential amplifier OP1: operator CS1: signal

FIG. 1 is a schematic diagram of a touch display according to an embodiment of the invention. FIG. 2 is a schematic diagram of a touch display according to another embodiment of the invention. FIG. 3 is a schematic diagram of signal waveforms of a touch sensing operation according to an embodiment of the present invention. FIG. 4 illustrates an implementation of a touch sensing controller according to an embodiment of the present invention. 5A and 5B respectively show a schematic diagram of a touch display according to another embodiment of the present invention and a diagram of the relationship between its resistance value and noise level. 6A and 6B respectively show a schematic diagram of a touch display according to another embodiment of the present invention and a diagram of the relationship between its resistance value and noise level.

100: Touch display

110: pixel array

120: filter substrate

130: shielding layer

R1: resistance

140: touch sensing layer

S1: First surface

S2: second surface

CP1, CP2: parasitic capacitance

VB: Reference voltage

Claims (10)

A touch display includes: a pixel array having a plurality of display pixels; a filter substrate covering the pixel array and having a first surface and a second surface opposite to each other; and a shielding layer disposed on the On the first surface or the second surface of the filter substrate; a first resistor, the first end of which is coupled to the shielding layer, the second end of the first resistor receiving a reference voltage; and a touch sensing layer , Covering the first surface of the filter substrate. In the touch display described in claim 1, wherein the reference voltage is a ground voltage. As described in the first item of the patent application, the touch display further includes a second resistor, the first end of the second resistor is coupled to the second end of the first resistor, and the second end of the second resistor receives A ground voltage. The touch display according to item 3 of the scope of patent application, wherein the resistance value of the first resistor is not greater than the resistance value of the second resistor. The touch display according to the first item of the scope of patent application further includes: a touch sensing controller coupled to the touch sensing layer, the shielding layer and the first end of the first resistor. The touch display according to claim 4, wherein the touch sensing controller receives a touch signal on the touch sensing layer and a reference signal on the first end of the first resistor, The touch sensing controller makes the touch signal and the reference signal as a differential signal pair to perform signal processing actions. For the touch display described in item 5 of the scope of patent application, the touch sensing controller includes: a differential amplifier, which receives the differential signal pair, and calculates the difference between the touch signal and the reference signal Produce touch results. As described in the first item of the patent application, the shielding layer is a transparent conductive film layer. The touch display according to claim 1, wherein the first surface of the filter substrate is the outer surface of the filter substrate, and the second surface of the filter substrate is the inner surface of the filter substrate . According to the first item of the scope of patent application, the touch display, wherein the filter substrate is a color filter substrate.

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