A design structure of Incell broken code touch display ITO

Abstract

The present invention discloses a design structure of an Incell broken-code touch display screen ITO, including a touch screen, a touch MCU, an active shielding routing, a signal transmission FPC cable, and a touch signal routing; the touch screen includes an upper ITO glass, a lower ITO glass, and a touch electrode; the touch MCU is soldered on a PCB board through a patch; the touch MCU is used to complete the collection and processing of the touch charge size; the active shielding routing is connected to the pin of the touch MCU after being connected in series with a 10KΩ patch resistor; the active shielding routing is mainly used to complete the balance of the touch charge and maintain the stability of the collected touch charge. The present invention designs an active shielding routing around the edge of the same layer of the touch electrode area, connects the touch signal and the active shielding routing signal to the touch MCU at the same time through the signal transmission FPC cable, and applies the same signal waveform as the touch electrode on the active shielding signal through the touch MCU, thereby suppressing and slowing down the charge loss of the touch signal, isolating the shielding interference, and realizing the improvement of touch sensitivity.

Description

Technical Field

[0001] The present invention relates to the field of liquid crystal display touch technology, and in particular to a design structure of an Incell broken code touch display screen ITO. Background Art

[0002] With the increasing popularity of smart products, more and more display screens are equipped with touch functions. The broken-code display touch screens on the market are all designed and fitted by Oncell, mostly using COF (Chip On FPC) welding to transmit touch information to the motherboard through FPC.

[0003] However, firstly, because the screen is relatively thick after the cover protective glass, touch panel, and display panel are bonded together, the display device cannot be made thin and light.

[0004] Secondly, in some application fields that do not require thickness, in order to reduce costs and omit the touch panel, even if the Incell solution is made by a larger LCD factory, due to its depth and maturity of control and understanding of the compact ITO layout and wiring process dimensions, especially the understanding of the design dimensions of the touch electrode when the same ITO glass layer is embedded in the same ITO display ITO routing and the understanding of the design dimensions of the touch electrode 105 model, the designed Incell touch display solution is very poor, and the phenomena of touch random reporting, multiple reporting, and insensitivity are very serious. In addition, without corresponding shielding protection treatment, the touch screen is seriously affected by common mode interference, affecting the use of the product. Summary of the invention

[0005] The purpose of the present invention is to propose a design structure of an Incell broken-code touch display screen ITO in order to solve the above-mentioned problem.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The invention discloses a design structure of an Incell broken-code touch display screen ITO, comprising a touch screen, a touch control MCU, an active shielding wiring, a signal transmission FPC wiring, and a touch control signal wiring.

[0008] The touch screen comprises an upper ITO glass, a lower ITO glass and a touch electrode.

[0009] The touch control MCU is soldered on the PCB board through a patch.

[0010] The touch control MCU is used to complete the collection and processing of the touch control charge size.

[0011] The active shielding trace is connected in series with a 10KΩ chip resistor and then connected to the pin of the touch control MCU.

[0012] The active shielding wiring is mainly used to balance the touch charge and maintain the stability of the collected touch charge.

[0013] The touch signal wiring is connected in series with a 1KΩ chip resistor and then connected to the pin of the touch MCU.

[0014] The signal transmission FPC cable is used to connect the touch screen and the touch control MCU.

[0015] As a further description of the above technical solution:

[0016] The upper ITO glass and the lower ITO glass are bonded and connected by frame glue at all sides.

[0017] The inner side surface of the upper ITO glass (207) is surrounded by a Shield-Ground electrostatic shielding wiring (203) and a display pattern corresponding signal COM-ITO wiring (202) in sequence from the outside to the inside; the inner side surface of the lower ITO glass (212) is surrounded by a Shield-Ground electrostatic shielding wiring (203), an active shielding wiring (101), a touch signal wiring (104), a touch electrode (105) and a display pattern corresponding signal SEG-ITO wiring (205) in sequence from the outside to the inside;

[0018] The lower surface of the upper ITO glass and the upper surface of the lower ITO glass are both bonded with PI alignment films by adhesive coating, and liquid crystal molecules are arranged between the PI alignment films.

[0019] An ITO conductive film is provided on the upper surface of the upper ITO glass, an ITO conductive film-free area is provided on one side of the upper surface of the upper ITO glass, a filter glass is provided on the upper surface of the ITO conductive film, and a cover glass is connected to the upper surface of the filter glass through OCR full bonding.

[0020] As a further description of the above technical solution:

[0021] The model of the touch control MCU is ATtiny1616.

[0022] As a further description of the above technical solution:

[0023] The signal transmission FPC cable adopts a 10PIN cable.

[0024] As a further description of the above technical solution:

[0025] The gold fingers on the signal transmission FPC cable are welded and fixed on the lower ITO glass through a bonding process to achieve the connection between the touch screen and the touch MCU on the PCB board.

[0026] As a further description of the above technical solution:

[0027] The display pattern corresponding signal SEG-ITO wiring is embedded in the touch electrode.

[0028] As a further description of the above technical solution:

[0029] The horizontal distance between the pads of adjacent touch electrodes is 7 mm, and the vertical distance between the pads is 5.5 mm.

[0030] As a further description of the above technical solution:

[0031] The design size of the touch electrode is 14mm*10mm.

[0032] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0033] 1. In the present invention, the touch electrodes and the working display pattern SEG-ITO wiring are simultaneously made on the upper surface of the lower ITO glass in the liquid crystal screen, and the pattern of the touch display button is embedded in the area of ​​the touch electrode, thereby eliminating the use of the display panel and the touch panel, reducing the screen thickness, and improving the lightness and thinness of the display device.

[0034] 2. In the present invention, an active shielding trace is designed around the same surface of the touch electrode area, and the touch signal and the active shielding trace signal are simultaneously connected to the touch MCU through the signal transmission FPC cable. The touch MCU applies the same signal waveform as the touch electrode to the active shielding trace, thereby suppressing and slowing down the charge loss of the touch signal, isolating and shielding interference, and improving the touch sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic diagram of the stacked structure of a touch screen having a design structure of an Incell broken-code touch display screen ITO provided according to an embodiment of the present invention is shown.

[0036] Figure 2 A schematic diagram of the circuit structure of a design structure of an Incell broken-code touch display screen ITO provided according to an embodiment of the present invention is shown.

[0037] Figure 3 A schematic diagram of the equivalent principle of a touch fingertip and touch control technology implemented in a design structure of an Incell broken-code touch display screen ITO provided according to an embodiment of the present invention is shown.

[0038] Legend:

[0039] 101. Active shielding routing; 102. Signal transmission FPC cable; 104. Touch signal routing; 105. Touch electrode; 106. Filter glass; 200. Cover glass; 201. Area without ITO conductive film; 202. Display pattern corresponding signal COM-ITO routing; 203. Shield-Ground electrostatic shielding routing; 205. Display pattern corresponding signal SEG-ITO routing; 206. ITO conductive film; 207. Upper ITO glass; 208. Glue coating; 209. PI alignment film; 210. Liquid crystal molecules; 211. Frame glue; 212. Lower ITO glass. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] See also Figure 1-3 A design structure of an Incell broken-code touch display screen ITO includes a touch screen, a touch MCU, an active shielding wiring 101, a signal transmission FPC cable 102, and a touch signal wiring 104.

[0042] The touch screen includes an upper ITO glass 207 , a lower ITO glass 212 and a touch electrode 105 .

[0043] The touch MCU is soldered on the PCB board through SMD.

[0044] The touch MCU is used to complete the collection and processing of the touch charge size.

[0045] The active shielding trace 101 is connected in series with a 10KΩ chip resistor and then connected to the pin of the touch control MCU.

[0046] The active shielding wiring 101 is mainly used to balance the touch charge and maintain the stability of the collected touch charge.

[0047] The touch signal trace 104 is connected to the pin of the touch MCU after being connected in series with a chip resistor of 1KΩ.

[0048] The signal transmission FPC cable 102 is used to connect the touch screen and the touch control MCU.

[0049] In the static model when a human hand does not touch the touch electrode 105 (Touch-key), there are parasitic capacitance Cp of the touch electrode 105 itself, capacitance Cx (self-capacitance) of the touch electrode 105 itself, and ground return capacitance Cg.

[0050] When touching, touch capacitance CT, human body capacitance Ch and human body equivalent series resistance Rh are introduced.

[0051] The touch capacitance CT is limited by the size of the touch electrode 105 sensor and the thickness / material of the touch cover layer, and 0.1pF-1pF is recommended. The human body capacitance Ch is usually 100pF to 200pF. Cg is the coupling capacitance between the DC ground and the earth, and is usually 1pF-10pF. When the DC ground is directly connected to the earth, the capacitance is infinite. The grounding return path provided by the human body capacitance Ch and the capacitance Cg from the earth to the system equipment ground will reduce the transfer of charge.

[0052] Since CT is much smaller than Ch and CT is smaller than Cg, in this equivalent circuit, the capacitance change collected by the touch MCU is the change in capacitance on CT, while in the equivalent series capacitor circuit, the change in the small capacitance CT determines the change in the measured capacitance.

[0053] Through the series capacitors, we can get: Ctotal= (Ch*Cg) / (Ch+Cg); the capacitance calculated by Ctotal is basically the same as the capacitance value of CT, that is, the smallest capacitance value determines the total capacitance change. Reducing the size of Cg will significantly reduce the touch sensitivity. Therefore, in the series capacitors, the smallest capacitance value plays a dominant role, that is, the size of the sensing capacitance CT value when the fingertip touches and the ground return capacitance Cg.

[0054] Therefore, in the design, the touch sensing CT value cannot be affected by Cg, and an active shielding line 101 is introduced. The touch MCU actively applies the same level as the touch electrode 105 to maintain the stability of the charge on the touch signal line 104. At the same time, it isolates and keeps away from the ground signal with a return path to improve touch sensitivity.

[0055] Specifically, Figure 1 As shown, the upper ITO glass 207 and the lower ITO glass 212 are bonded and connected by frame glue 211 on all sides.

[0056] The inner side surfaces of the upper ITO glass 207 and the lower ITO glass 212 are sequentially surrounded by Shield-Ground electrostatic shielding traces 203 from the outside to the inside, the lower surface of the upper ITO glass 207 is provided with a display pattern corresponding signal COM-ITO trace 202, and the upper surface of the lower ITO glass 212 is provided with an active shielding trace 101, a touch electrode 105, a touch signal trace 104 and a display pattern corresponding signal SEG-ITO trace 205.

[0057] The lower surface of the upper ITO glass 207 and the upper surface of the lower ITO glass 212 are both bonded with PI alignment films 209 through adhesive 208 , and liquid crystal molecules 210 are arranged between the PI alignment films 209 .

[0058] An ITO conductive film 206 is provided on the upper surface of the upper ITO glass 207, an ITO conductive film-free area 201 is provided on one side of the upper surface of the upper ITO glass 207, a filter glass 106 is provided on the upper surface of the ITO conductive film 206, and a cover glass 200 is connected to the upper surface of the filter glass 106 by OCR full bonding.

[0059] In the touch screen stacking structure corresponding to the present design structure, the thickness of the cover glass 200 is 1.8 mm.

[0060] The thickness of the OCR bonding glue used in the OCR full bonding technology used in the filter glass 106 is 0.2 mm; the thickness of the filter glass 106 is 0.5 mm.

[0061] The corresponding thickness of the upper ITO glass 207 is 0.7 mm. This ITO glass is a double-sided ITO glass and has high light transmittance together with the lower ITO glass 212. The upper surface touch display area is an area without ITO conductive film 201, and other display areas have a whole piece of ITO conductive film 206 for ESD static protection.

[0062] The lower surface of the upper ITO glass 207 is the display pattern corresponding signal COM-ITO wiring 202, which corresponds to the working display pen tip. Under the action of the glue 208, the PI alignment film 209 forms an electrode corresponding to the display pattern corresponding signal SEG-ITO wiring 205 on the upper surface of the lower ITO glass 212. When working, there is a self-built electric field between the display pattern corresponding signal COM-ITO wiring 202 and the display pattern corresponding signal SEG-ITO wiring 205. The directional electric field force formed by this self-built electric field causes the liquid crystal molecules 210 to rotate in a directional manner. Then, the bottom backlight will project the display color film pattern, and the pattern corresponding to the display pen tip on the touch screen can be seen.

[0063] The thickness of the liquid crystal molecules 210 is less than 10 um, and the thickness of the PI alignment film 209 and the glue 208 between the upper ITO glass 207 and the lower ITO glass 212 can be ignored.

[0064] In summary, the distance from the upper surface of the lower ITO glass 212 where the touch electrode 105 is located to the cover glass 200 where a finger touches is 3.2 mm, which reduces the thickness of the screen and improves the thinness of the display device.

[0065] Specifically, Figure 2 As shown, the touch MCU model is ATtiny1616.

[0066] Specifically, Figure 2 As shown, the signal transmission FPC cable 102 adopts a 10PIN cable.

[0067] Specifically, Figure 2 As shown, the gold fingers on the signal transmission FPC cable 102 are welded and fixed on the lower ITO glass 212 by a bonding machine to achieve the connection between the touch screen and the touch MCU on the PCB board.

[0068] Specifically, Figure 1 As shown, the display pattern corresponding signal SEG-ITO wiring 205 is embedded in the touch electrode 105 .

[0069] Specifically, Figure 2 As shown, the horizontal distance between the pads of adjacent touch electrodes 105 is 7 mm, and the vertical distance between the pads is 5.5 mm.

[0070] Among them, the touch electrode 105 itself has a high self-capacitance. If it is close to other adjacent sensors, the self-capacitance will increase due to the influence of distributed capacitance. The larger the load capacitance, the larger the time constant will be. The touch sensor will take a longer time to complete charging and discharging, which will cause a time delay in touch detection and increase power consumption. Therefore, a certain distance must be maintained between touch sensor electrodes, and corresponding considerations must be made in particularly dense layout routing.

[0071] Specifically, Figure 2 As shown, the design size of the touch electrode 105 is 14 mm*10 mm.

[0072] Among them, according to the parallel plate capacitance formula, it can be known that the size of the induced capacitance when the fingertip touches is directly related to the thickness between the parallel electrode plates touched. The thickness of the touch cover layer will increase the distance between the fingertip and the touch electrode 105 sensor pad fingertip, resulting in a decrease in the capacitance between the finger and the touch electrode 105 sensor electrode fingertip. The touch MCU detects a smaller amount of charge change, and the touch sensitivity will be significantly reduced. At the same time, the thicker touch cover layer will also expand the self-electric field formed between the fingertip and the electrode. Therefore, it is necessary to compensate by increasing the size of the touch electrode 105 pad so that each sensor electrode can sense the range of the fingertip contact point. The approximate touch diameter of a human finger is 5mm-10mm, and the typical value is 8mm, that is, the diameter of the touch electrode 105 pad size must be greater than 8mm, and the excess part should be greater than the thickness of the cover layer, that is, 8mm plus 3.2mm, at least 11.2mm.

[0073] The layout of the touch electrode 105 in the implementation case of this design structure is limited by the display pattern corresponding electrode signal SEG-ITO routing 205 and the size distribution of all (8 touch electrodes) touch electrodes 105. In order to achieve higher touch sensitivity. In actual design applications, the size of the touch electrode 105 is not only limited by the size of the display area, but also affected by the display pattern corresponding signal COM-ITO routing 202 and the display pattern corresponding signal SEG-ITO routing 205. In order to achieve better display patterns and touch functions, the design size of the rectangular touch electrode 105 in this design structure is: 10mm*14mm in width*length, and the diameter of the circular touch electrode 105 is 10mm.

[0074] The size of the rectangular touch electrode 105 with a circular design diameter of 10mm and a size of 10mm*14mm are both larger than the average area of ​​the tip of an adult's finger. For a touch electrode 105 that is too small, such as an 8mm touch electrode 105, the area parallel to the fingertip is the largest and the largest increment is generated only when the center contact is made. As long as the area of ​​the touch electrode 105 is large enough, the touch sensor can be activated without precisely touching the center of the electrode 105, and is only affected by the size of the touch area of ​​the fingertip, and is not affected by the size of the area of ​​the sensor touch electrode 105.

[0075] A too small touch area reduces the sensitivity and makes the experience worse, while an overly large sensor electrode pad size will couple with the approaching hand before the fingertip touches, affecting the adjacent touch electrodes 105 and causing a proximity effect. In addition, an overly large design size cannot meet the number requirement of touch electrodes 105 within the limited design size. Therefore, when the overall design size of the touch electrode 105 sensor pad is limited, it is necessary to reasonably allocate the size of the touch electrode 105 and the distance between adjacent touch electrodes 105. Figure 2 As shown, the horizontal distance between the pads of adjacent touch electrodes 105 is 7 mm, and the vertical distance between the pads is 5.5 mm.

[0076] The working principle of the present invention is: when in use, after a human hand touches the touch electrode 105, under the action of the active shielding wiring 101, the touch MCU actively applies the same electrical level as the touch electrode 105 to maintain the stability of the charge on the touch signal wiring 104, while isolating and keeping away from the ground signal with a return path, thereby improving touch sensitivity.

[0077] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A design structure of an Incell broken code touch display screen ITO, characterized in that: It includes a touch screen, a touch MCU, an active shielding wiring (101), a signal transmission FPC cable (102), and a touch signal wiring (104); The touch screen comprises an upper ITO glass (207), a lower ITO glass (212) and a touch electrode (105); The touch control MCU is soldered on the PCB board through a patch; the touch control MCU is used to complete the collection and processing of the touch control charge size; The active shielding wiring (101) is connected in series with a 10KΩ chip resistor and then connected to the pin of the touch control MCU; the active shielding wiring (101) is mainly used to balance the touch control charge and maintain the stability of the collected touch control charge; The touch signal wiring (104) is connected in series with a 1KΩ chip resistor and then connected to the pin of the touch MCU; The signal transmission FPC cable (102) is used to realize the connection between the touch screen and the touch control MCU; The upper ITO glass (207) and the lower ITO glass (212) are bonded and connected around the periphery by means of a frame glue (211); The inner side surface of the upper ITO glass (207) is surrounded by Shield-Ground electrostatic shielding wiring (203) and display pattern corresponding signal COM-ITO wiring (202) in sequence from the outside to the inside; The inner side surface of the lower ITO glass (212) is surrounded by a Shield-Ground electrostatic shielding wiring (203), an active shielding wiring (101), a touch signal wiring (104), a touch electrode (105) and a display pattern corresponding signal SEG-ITO wiring (205) in sequence from the outside to the inside; The lower surface of the upper ITO glass (207) and the upper surface of the lower ITO glass (212) are both bonded with PI alignment films (209) by means of adhesive coating (208), and liquid crystal molecules (210) are arranged between the PI alignment films (209); An ITO conductive film (206) is provided on the upper surface of the upper ITO glass (207); an ITO conductive film-free region (201) is provided on one side of the upper surface of the upper ITO glass (207); a filter glass (106) is provided on the upper surface of the ITO conductive film (206); and a cover glass (200) is connected to the upper surface of the filter glass (106) through OCR full bonding.

2. The design structure of an Incell broken code touch display screen ITO according to claim 1 is characterized in that: The model of the touch control MCU is ATtiny1616.

3. The design structure of an Incell broken code touch display screen ITO according to claim 1 is characterized in that: The signal transmission FPC cable (102) adopts a 10-pin cable.

4. The design structure of an Incell broken code touch display screen ITO according to claim 1 is characterized in that: The gold fingers on the signal transmission FPC cable (102) are welded and fixed on the lower ITO glass (212) by a bonding machine, so as to achieve connection between the touch screen and the touch control MCU on the PCB board.

5. The design structure of an Incell broken code touch display screen ITO according to claim 1 is characterized in that: The display pattern corresponding signal SEG-ITO wiring (205) is embedded in the touch electrode (105).

6. The design structure of an Incell broken code touch display screen ITO according to claim 1 is characterized in that: The horizontal distance between the pads of adjacent touch electrodes (105) is 7 mm, and the vertical distance between the pads is 5.5 mm.

7. The design structure of an Incell broken code touch display screen ITO according to claim 1 is characterized in that: The design size of the touch electrode (105) is 14 mm*10 mm.

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