Touch display screen

Abstract

The invention discloses a touch display screen which comprises a screen shell, a touch display device arranged on the screen shell and a driving control system arranged in the screen shell, and the driving control system is connected with the touch display device. The touch display device includes a glass substrate; the glass substrate is prepared from the following raw materials: SiO2, Al2O3, B2O3, MgO, CaO, SrO, BaO and SnO2. The silica structure of SiO2 is used as the most stable three-dimensional space structure in a glass network, so that the glass material has higher mechanical strength. Al2O3 is used for enhancing the thermal stability, chemical stability and mechanical strength of the glass. B2O3 plays a role of a fluxing agent and can reduce the melting point, dielectric constant, dielectric loss and the like of the glass. By adopting the combination of MgO, CaO, SrO and BaO alkaline earth metal oxides, the physical properties of the glass are improved, and the wear resistance and thermal shock resistance are enhanced. And a better glass substrate material is provided for preparing a large-size touch screen.

Description

[0001] This application is a divisional application of patent number "202410229925.7", application date "2024-02-29", and name "A capacitive touch screen and drive control system". Technical Field

[0002] The present invention belongs to the technical field of capacitive touch screens, and in particular relates to a touch display screen. Background Art

[0003] Under the OLED (Organic Light Emitting Diode) technology, LED glass light display technology has shown attractive features, including the advantages of high flatness, high transparency and high temperature resistance of the substrate. These advantages have made LED glass light display technology widely used in various fields, and new display technologies such as Mini-LED and Micro-LED have also been developed, showing huge market potential.

[0004] With the development of display technology, electronic devices are becoming thinner and lighter, and display screens are becoming larger and larger. The trend of touch screens becoming larger and thinner is also an inevitable requirement of the times. However, the applicant has found that the existing technology has the following problems:

[0005] Regardless of the display technology used by the touch screen, whether OLED, Mini-LED or Micro-LED, TFT is required to drive it, and glass substrate is the best material for TFT backplane. For glass substrates used for TFT, the surface of the glass must go through processes such as coating, exposure, etching, sputtering, and chemical vapor deposition to eventually form TFT on the surface of the glass. On the other hand, glass cannot contain alkali metal oxides, as alkali metals will deteriorate the performance of semiconductor films. This means that when preparing large-size touch screens, the glass substrate needs to have better physical properties, thermal stability, and chemical stability, which greatly increases the technical threshold for glass substrates. Summary of the invention

[0006] The purpose of the present invention is to solve the above technical problems and provide a touch display screen.

[0007] In order to solve the above problems, the present invention is implemented according to the following technical solutions:

[0008] In a first aspect, the present invention provides a touch display screen, comprising a screen housing, a touch display device disposed on the screen housing, and a drive control system disposed inside the screen housing, wherein the drive control system is connected to the touch display device;

[0009] The touch display device comprises a glass substrate; the glass substrate is made of the following raw materials: SiO 2、Al 2 O 3 , B 2 O 3 , MgO, CaO, SrO, BaO and SnO 2 .

[0010] In combination with the first aspect, the present invention further provides a first preferred implementation of the first aspect, specifically, in the composition of the raw materials of the glass substrate, SiO 2 The weight percentage concentration is 67.24%, Al 2 O 3 The weight percentage concentration is 12.35%, B 2 O 3 The weight percentage concentration is 10.30%, SnO 2 The weight percentage concentration of is 0.16%, and the sum of the weight percentage concentrations of MgO, CaO, SrO and BaO is 9.95%.

[0011] In combination with the first aspect, the present invention further provides a second preferred implementation manner of the first aspect, specifically, the glass substrate is prepared by the following preparation method:

[0012] According to the composition of each raw material of the glass substrate, the batch material is mixed evenly;

[0013] Add the batch material into a quartz crucible at 1200℃, then heat it up to 1680℃ and keep it warm for 2h. Stir the glass liquid appropriately during the melting process.

[0014] Then the temperature is lowered to 1560℃, and the glass liquid is introduced into the preheated mold. After cooling to a certain temperature, annealing treatment is carried out. The annealing point temperature is 710℃, and then it is cooled to room temperature at a cooling rate of 2℃ / min.

[0015] In combination with the first aspect, the present invention further provides a third preferred implementation manner of the first aspect, specifically, the touch display device adopts an AMOLED with an On-Cell structure, and the touch display device includes three parts: a cover glass, a touch screen and an AMOLED screen;

[0016] The touch display device includes a cover glass, a polarizing layer, an ITO layer and an encapsulation glass, an organic material layer, a TFT driving layer and a glass substrate which are sequentially arranged from top to bottom.

[0017] In combination with the first aspect, the present invention further provides a fourth preferred implementation of the first aspect, specifically, the TFT driving layer has a multi-layer composite ITO thin film structure, and the multi-layer composite ITO thin film structure is bonded to the surface of the glass substrate.

[0018] In combination with the first aspect, the present invention also provides a fifth preferred implementation of the first aspect, specifically, the multilayer composite ITO film structure includes a bottom ITO film, a middle Ag film, a middle Ni film and a top ITO film.

[0019] In a second aspect, the present invention further provides a drive control system, which is arranged in a touch display screen according to the first aspect, and is connected to a touch display device of the touch display screen; wherein the drive control system comprises:

[0020] A plurality of channel selectors, wherein the plurality of channel selectors are connected to the touch display device;

[0021] A plurality of operational amplifiers, wherein the plurality of operational amplifiers are connected to the plurality of channel selectors correspondingly;

[0022] At least one ADC digital-to-analog converter, wherein the ADC digital-to-analog converter is connected to the operational amplifier;

[0023] An FPGA controller, wherein the FPGA controller is connected to the operational amplifier;

[0024] A voltage boosting circuit is connected to the FPGA controller, and the voltage boosting circuit is connected to the touch display device.

[0025] In combination with the second aspect, the present invention further provides a first preferred implementation of the second aspect, specifically, the FPGA controller includes:

[0026] A data acquisition and peripheral circuit control module, wherein the data acquisition and peripheral circuit control module is respectively connected to the channel selector, the operational amplifier and the ADC digital-to-analog converter; the data acquisition and peripheral circuit control module is also used to generate a row excitation signal and periodically generate an excitation pulse;

[0027] A data processing and touch position search module, which performs filtering processing on the ADC data of the ADC digital-to-analog converter, updates the baseline data, and selects a threshold, and searches and detects the processed data to find out whether there is a touch point;

[0028] A coordinate calculation and reporting module, which is used to calculate the touch point coordinates according to the collected data and the corresponding row and column information, and to package all the calculated touch point coordinates according to a preset protocol and send them through the serial port;

[0029] A main control module, wherein the main control module is respectively connected to the data acquisition and peripheral circuit control module, the data processing and touch position search module and the coordinate calculation and reporting module.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention provides a touch display screen, comprising a screen shell, a touch display device arranged on the screen shell, and a drive control system arranged inside the screen shell, wherein the drive control system is connected to the touch display device; the touch display device comprises a glass substrate; the glass substrate is made of the following raw materials: SiO 2 、Al 2 O 3 , B 2 O 3 , MgO, CaO, SrO, BaO and SnO 2 .

[0032] As touch screens become larger in size, the dimensional stability and especially the physical strength of glass substrates become more challenging. The glass substrate prepared by the present invention has better thermal stability, chemical stability and mechanical strength. 2 The silicon-oxygen structure is the most stable three-dimensional structure in the glass network, which enables the glass material to have high mechanical strength. 2 O 3 Used to enhance the thermal stability, chemical stability and mechanical strength of glass. 2 O 3 It acts as a flux, which can reduce the melting point, dielectric constant and dielectric loss of glass. The combination of MgO, CaO, SrO and BaO alkaline earth metal oxides is used to improve the physical properties of glass, enhance wear resistance and thermal shock resistance, and provide better glass substrate materials for the preparation of large-size touch screens. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The specific embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings, wherein:

[0034] Figure 1 It is a schematic diagram of the assembly of the touch display screen of the present invention;

[0035] Figure 2 is a schematic diagram of the layer structure of the touch display device of the present invention;

[0036] Figure 3 It is a circuit hardware structure block diagram of the drive control system of the present invention;

[0037] Figure 4 It is the architectural design diagram of the FPGA controller of the present invention;

[0038] Figure 5 It is a structural schematic diagram of the data acquisition and peripheral circuit control module of the present invention;

[0039] In the figure:

[0040] 10- Touch display device;

[0041] 20-Screen casing. DETAILED DESCRIPTION

[0042] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0043] With the continuous improvement of OLED technology, the luminescence characteristics of OLED have gradually transitioned from fluorescent emission and phosphorescent emission to TADF (thermally excited delayed fluorescence) emission; the control of OLED display is mainly achieved through TFT, and the current technical difficulties of OLED are mainly: the development technology of large-size display screens still needs to be strengthened.

[0044] In this field, glass substrate is the best material for TFT backplane. The glass substrate used for TFT needs to go through processes such as coating, exposure, etching, sputtering, chemical vapor deposition, etc., and finally TFT is formed on the surface of the glass.

[0045] The applicant has found that large-size touch screens have higher performance requirements for each component, and the glass substrate used in TFT cannot contain alkali metal oxides, because alkali metals will deteriorate the performance of semiconductor films. Therefore, when preparing large-size touch screens, the glass substrate needs to have better thermal and chemical stability, which greatly increases the technical threshold of the glass substrate.

[0046] To this end, the present invention innovates and optimizes the glass substrate, and the glass substrate prepared by the present invention has better thermal stability, chemical stability and mechanical strength, providing a better glass substrate material for preparing large-size touch screens, and better meeting the production needs of large-size and ultra-thin touch screens.

[0047] Embodiment 1

[0048] like Figure 1 As shown, the present invention provides a touch display screen, including a screen shell, a touch display device arranged on the screen shell, and a drive control system arranged inside the screen shell, wherein the drive control system is connected to the touch display device.

[0049] In the present invention, in order to adapt to the structural requirements of a large-size touch display screen, the screen housing is made of metal material, such as aluminum alloy. The screen housing includes a shell and a frame, and the circuit components of the drive control system are installed on the installation part of the shell, and the touch display device is installed through the cooperation of the shell and the frame.

[0050] It should be noted that the related products and product structures of the touch display screen are common knowledge in the art and are also conventional products in the art, and no further explanation is given here.

[0051] In a specific implementation, the touch display device includes a glass substrate; the glass substrate is made of the following raw materials: SiO 2 、Al 2 O 3 , B 2 O 3 , MgO, CaO, SrO, BaO and SnO 2 .

[0052] Specifically, the SiO 2 The silicon-oxygen structure is the most stable three-dimensional structure in the glass network, which enables the glass material to have high mechanical strength. 2 O 3 Used to enhance the thermal stability, chemical stability and mechanical strength of glass. 2 O 3 It acts as a flux, which can reduce the melting point, dielectric constant and dielectric loss of glass. The combination of MgO, CaO, SrO and BaO alkaline earth metal oxides is used to improve the physical properties of glass and enhance wear resistance and thermal shock resistance.

[0053] In a specific implementation, among the raw materials of the glass substrate, SiO 2 The weight percentage concentration is 67.24%, Al 2 O 3 The weight percentage concentration is 12.35%, B 2 O 3 The weight percentage concentration is 10.30%, SnO 2 The weight percentage concentration of is 0.16%, and the sum of the weight percentage concentrations of MgO, CaO, SrO and BaO is 9.95%.

[0054] The present invention also provides a specific preparation example 1 of a glass cover plate. The raw material composition and preparation method of example 1 are as follows:

[0055] 1. In Example 1, the composition of the raw materials of the glass substrate is shown in the following table:

[0056] Raw material composition <![CDATA[SiO 2 ]]> <![CDATA[Al 2 THE 3 ]]> <![CDATA[B 2 THE 3 ]]> <![CDATA[SnO 2 ]]> MgO CaO SrO BaO Weight percentage concentration 67.24％ 12.35％ 10.30％ 0.16％ 1.28％ 7.18％ 0.91％ 0.58％

[0057] In this example 1, the glass cover plate is prepared by the following preparation method:

[0058] According to the composition of each raw material of the glass substrate, the batch material is mixed evenly;

[0059] Add the batch material into a quartz crucible at 1200℃, then heat it up to 1680℃ and keep it warm for 2h. Stir the glass liquid appropriately during the melting process.

[0060] Then the temperature is lowered to 1560℃, and the glass liquid is introduced into the preheated mold. After cooling to a certain temperature, annealing treatment is carried out. The annealing point temperature is 710℃, and then it is cooled to room temperature at a cooling rate of 2℃ / min.

[0061] In a preferred implementation, in order to improve the product yield, the particle size of each raw material of the present application is preferably 30-50 mesh. The surface energy of the raw material with too fine particle size is large, and the surface adsorption and condensation effect are also correspondingly large, and agglomeration is easy to occur during mixing; the raw material with too coarse particle size will make the surface area of ​​the raw material relatively small, and the contact area between the raw materials is also relatively small, and the melting rate of the raw material is low, and the raw material will not be completely melted, resulting in a decrease in the success rate of glass melting. For this reason, the present invention improves the success rate of electronic substrate glass melting by using a specific particle size.

[0062] 2. Product Testing

[0063] Sample preparation: According to the description of Example 1, multiple glass substrate tests were prepared and the following tests were performed.

[0064] (1) Density test: The density of the glass substrate sample of Example 1 was measured using the Archimedes method. Where p is the density of the glass sample (g / m 3 );m 1 is the mass of the glass substrate sample in air (g); m 2 The mass of the wire in air (g); m 3 is the mass of the glass substrate sample in water (g); m 4 is the mass of the wire in water (g); p 1 is the density of water (g / m 3 );0.0012 is the density compensation coefficient at room temperature.

[0065] The experimental study found that in the comparative example, the density of the glass sample showed an increasing trend with the increase of MgO and CaO content. With the increase of SrO content, the density showed a trend of increasing first and then decreasing, and a maximum value appeared at the SrO content of 0.96wt%. With the increase of BaO content, the density showed a trend of decreasing first and then increasing, and a minimum value appeared at the BaO content of 0.8wt%.

[0066] Alkaline earth metal oxides are network outsiders and do not participate in the formation of the network, but play a role in breaking the network in the glass structure. 2+ and Sr 2+The larger relative atomic mass of the glass will affect the average atomic mass of the glass, resulting in an increase in the density of the glass. At the same time, adding cations with smaller radius, such as Mg 2+ and Ca 2+ Although it will cause the breakage of the silicon-oxygen tetrahedral connection, these ions fill the gaps in the aluminum borosilicate network and do not cause the expansion of the network structure. 2+ , Ca 2+ The structure is tight and the density is increased. Continuously adding alkaline earth metal oxides to the glass provides more free oxygen to make [B0 3 ] is converted to [B0 4 ], the coordination number changes and the density increases, connecting the bonds in the structure that are broken due to the addition of alkaline earth metal oxides, [B0 4 ] volume ratio [Si0 4 ] is small, which can make the glass structure compact and increase the density.

[0067] As the content of BaO increases, the density increases first and then decreases. The reason is that the addition of cations with larger radius, such as Ba 2+ Etc., because their radius is larger than the network gap, the network structure expands, resulting in a decrease in density.

[0068] (2) Hardness: The hardness of the glass substrate sample of Example 1 was tested by the Vickers microhardness indentation test method. The test principle is to use an indenter with 1360 diamond regular quadrangular pyramids on two opposite sides to apply a certain load for a period of time, so as to press a diamond-shaped indentation on the surface of the glass sample. Finally, the hardness of the glass sample is obtained by dividing the applied load by the area of ​​the indentation.

[0069] In the experimental study, the content of alkaline earth metal oxide was changed as a comparative experiment. The glass substrate sample prepared in Example 1 contained about 10% B 2 0 3 , so they all have high hardness and the hardness is above 670MPa.

[0070] The comparative experiment found that when the content of alkaline earth metal oxides in the glass sample changes, the hardness of the glass sample shows a downward trend. This is because the structure of glass is mainly silicon-oxygen tetrahedron, [Si0 4 ] is the skeleton of glass, so changes in the density of the skeleton will cause changes in hardness.

[0071] Generally speaking, the network exosomes act as network breakers, which will reduce the hardness of the glass, while the network forming bodies will increase the hardness of the glass. Alkaline earth metal oxides belong to network exosomes. Changes in the content of alkaline earth metal oxides will cause the skeleton [Si0 4] is destroyed, causing the density of the glass sample network structure to decrease continuously, which is manifested in the form of reduced hardness on a macro scale.

[0072] The reason why the hardness of the glass formula of this patent is improved is that in a specific formula, a specific alkaline earth metal oxide content is used to increase the content of free oxygen, which makes a part of the glass structure [B0 3 ] is converted to [B0 4 ], thereby making the glass network structure more compact; on the other hand, by adding a specific proportion of MgO, CaO, SrO and BaO, under the mixed alkaline earth effect of the four alkaline earths, the two cations of magnesium ions and calcium ions in the glass network structure of this ratio have two different vacancies. The vacancies left by magnesium ions are not suitable for calcium ions, which changes the properties of vacancies and produces smaller potential energy, resulting in an increase in the coordination number of vacancies coordinated with oxygen, turning more bridging oxygen into non-bridging oxygen, and ultimately causing the glass network structure to show a trend of decreasing hardness on a macro scale. Finally, the hardness of the glass sample showed an upward trend.

[0073] In summary, the glass formula of this patent has the best hardness compared with the glass samples of other comparative experiments.

[0074] (3) Dielectric properties: The glass substrate sample of Example 1 was cut into thin slices of 15x10mm and about 1.2mm in height. After the sample was cleaned with an ultrasonic cleaner, low-temperature silver paste was plated on both sides of the sample. The sample was kept at 550°C for 0.5h and then cooled with the furnace to form a parallel plate capacitor. The capacitance of the sample was measured using an E4980A precision impedance analyzer, and the dielectric constant of the glass substrate sample of Example 1 was calculated. In the formula, ε r is the dielectric constant of the glass sample, F / m; C is the actual measured capacitance, F; S is the silver-plated area in square meters; ε 0 The dielectric constant of vacuum is 8.85x10 -12 F / m; d is the glass thickness (m).

[0075] The experiment found that alkaline earth metal oxides play a role in filling network gaps in the glass structure. With the increase of MgO, CaO, SrO and BaO, the filling rate of the gaps increases and the density increases. With the increase of the number of particles per unit volume, the dielectric constant increases, 5.84F / m. When alkaline earth metal oxides are added to the glass, non-bridging oxygen that is easily oxidized appears in the glass, thereby increasing the dielectric constant.

[0076] The dielectric constant of inorganic glass is generally between 4 and 20. When the dielectric constant is small, it can be used as a high-frequency insulation material, especially for high-voltage insulation. When the dielectric constant is large, it can be used as a capacitor, especially for making small capacitors. The dielectric properties of glass generally include dielectric constant, dielectric loss and dielectric strength.

[0077] (4) Thermal expansion coefficient: The glass substrate sample of Example 1 was cut into a cylinder of 25 mm x 6 mm, and the thermal expansion coefficient of the glass sample was measured using a DIL402PC thermal expansion instrument produced by NETZSCH, Germany.

[0078] Thermal expansion of glass is generally considered to be caused by heat energy, which is a change in the average spacing between vibrating atoms due to the incoordination of interatomic forces. The thermal expansion coefficient of the glass substrate sample of Example 1 of the present invention is 33.914×10 -7 ℃ -1 .

[0079] Interaction of alkaline earth metal oxide cations with the network and [Al0 4 ] are two key factors in determining the thermal expansion coefficient. In the formula of the present invention, magnesium ions interact less with the network than calcium ions, resulting in smaller thermal expansion. On the other hand, this patent reduces the content of CaO by adding a certain amount of MgO. Replacing CaO with MgO will make [Al0 4 ] is reduced, and the weaker interaction between the bound magnesium ions and the network will reduce the thermal expansion.

[0080] (5) Characterization of basic chemical properties

[0081] The glass substrate sample of Example 1 was cleaned by an ultrasonic cleaner before and after the experiment, and then weighed on an electronic balance with an accuracy of 0.0001g after drying.

[0082] (a) HF corrosion resistance The glass sample was placed in 250 mL of 10% HF solution and soaked at room temperature for 20 min. The residual HF and corrosion powder on the surface of the glass sample were then cleaned using a CNC ultrasonic cleaner. The sample was then dried and weighed, and its mass loss per unit surface area was calculated.

[0083] (b) Water erosion resistance: The glass sample was placed in 250 mL of distilled water and eroded in a constant temperature water bath at 95°C for 24 h. The mass loss per unit surface area was calculated according to the above method.

[0084] (c) NaOH corrosion resistance The glass sample was placed in 250 mL of 5% NaOH solution and corroded in a constant temperature water bath at 95°C for 6 h. The mass loss per unit surface area was then calculated using the above method.

[0085] The experiment found that, except for HF acid, other acids cannot directly react with electronic substrate glass, but corrode the glass through water. Therefore, this experiment uses HF acid to corrode the substrate glass sample in terms of acid resistance. HF acid not only exchanges ions with the glass surface, but also reacts with the components in the glass.

[0086] The study found that Ca 2+ and Ba 2+ It will react with silicate ions produced after the glass is corroded to form calcium silicate and barium silicate with extremely low solubility, thereby preventing the corrosion from continuing; there are also literatures showing that Mg2+ will form a magnesium-rich layer on the glass surface to prevent corrosion. Therefore, it can be speculated that calcium silicate, barium silicate or a magnesium-rich layer is likely to be generated on the surface of the glass sample, resulting in increased alkali resistance. On the other hand, in the NaOH solution, the NaOH solution continuously destroys the silicon-oxygen skeleton, making Si0 2 Continuously precipitate to form silicate ions. The Ca content in glass is relatively high, which combines with silicate ions to form calcium silicate, a flaky film on the surface of the glass, which covers the surface of the glass sample and can effectively prevent the glass from being further corroded.

[0087] In summary, the glass substrate of Example 1 of this patent has better thermal stability, chemical stability and mechanical strength.

[0088] Embodiment 2

[0089] The second embodiment provides a touch display screen, and its product structure, technical principle and technical effect are exactly the same as those of the first embodiment.

[0090] like Figure 2 As shown, the touch display screen described in the second embodiment has a touch display device that adopts an On-Cell structure AMOLED, and the touch display device includes three parts: a cover glass, a touch screen surface and an AMOLED screen; wherein the touch display device includes a cover glass, a polarizer layer, an ITO layer and encapsulation glass, an organic material layer, a TFT drive layer and a glass substrate that are arranged in sequence from top to bottom.

[0091] Compared with traditional LCD displays, AMOLED displays are thinner and lighter, and consume less energy. Since AMOLED uses RGB three-color pixel technology, there is no need for a color filter under the encapsulation glass. The touch sensing electrode can be made first, and then the OLED light-emitting device can be encapsulated.

[0092] In a preferred embodiment, the TFT driving layer has a multi-layer composite ITO film structure, and the multi-layer composite ITO film structure is bonded to the surface of the glass substrate. Specifically, the multi-layer composite ITO film structure includes a bottom ITO film, a middle Ag film, a middle Ni film, and a top ITO film.

[0093] Nowadays, with the demand for high-definition and large-size touch panels, the resistivity of ITO film needs to be further reduced on the basis of ensuring visible light transmittance to meet practical application requirements. However, it can be seen that there is a contradiction between the conductive properties and optical properties of ITO film. The demand for large-size panels and touch display devices is tight, and the resistivity of ITO film needs to be further reduced. The common method to reduce resistance is to increase the thickness of the film, but increasing the thickness of the ITO film will inevitably cause a significant decrease in light transmittance performance.

[0094] To this end, the present invention provides a novel multi-layer composite ITO film structure, realizing a sandwich structure of a dielectric material / metal / dielectric material (D / M / D) multi-layer film with improved light transmittance and high electrical conductivity. Specifically, the multi-layer composite ITO film structure includes a bottom ITO film, a middle metal Ni film, a middle Ag film, and a top ITO film. In this structure, a very thin metal film is embedded as an interlayer to improve electrical conductivity without affecting the transmittance of the dielectric material.

[0095] At present, research shows that when metal is used as a metal film in a D / M / D structure, film agglomeration sometimes occurs after heat treatment, resulting in the destruction of the film structure. Therefore, interface defect control and performance control are the key to the success of the D / M / D structure ITO film process and have important research value.

[0096] In this patent, ITO film is a material with excellent electrical conductivity and transmittance, and its crystal structure is relatively stable. A middle metal Ni film is introduced into the multi-layer composite ITO film structure to act as a barrier layer to limit the diffusion and oxidation of Ag atoms, thereby improving the stability of the film. The middle metal Ni film determines the electrical connection between the Ag film and the dielectric layer and the optical transmittance of the overall structure. The design of depositing Ni on the surface of the Ag film is conducive to its continuous growth, and at the same time it can realize the function of a barrier layer between Ag and the outer oxide, ensuring the stability of the film.

[0097] In a specific implementation, the multilayer composite ITO thin film structure of the present invention is prepared by the following method:

[0098] Considering that the thickness of the Ag and Ni films to be sputtered is small, if the deposition power is too large, the growth rate will be too fast, which will make the film thickness difficult to control, and if the power is too low, the crystallinity of the film will be poor. TIO is an oxide, and sputtering requires a higher power to ensure the deposition rate and the crystal structure of the film. Finally, it was determined that the deposition power of Ag and Ni is 40W, and that of TIO is 120W.

[0099] a. Turn on the main control switch of the magnetron sputtering equipment, and install the cleaned glass substrate of Example 1 on the substrate table. Install the ITO target material for the experiment at target position A, and set the target A substrate distance to 75mm. Install the Ag target material for the experiment at target position B, and set the target B substrate distance to 75mm. Install the Ni target material for the experiment at target position C, and set the target C substrate distance to 75mm. In order to prevent the surface of the Ag target and the Ni target from being contaminated when sputtering the ITO film, first cover the target positions B and C with the baffle connected to the manipulator;

[0100] b. Use a mechanical pump to pre-evacuate the low vacuum. When the vacuum reaches a certain value, use a molecular pump to evacuate the back low vacuum of the sputtering chamber to 5×10 -4 Pa. The required high-purity argon gas is introduced at a gas flow rate of 20 sccm. The pressure in the sputtering chamber is adjusted by a pressure regulating valve to make the pressure during sputtering 3Pa.

[0101] c. Sputter the bottom ITO film. Connect the DC power supply to target A, set the sputtering power to 120W, the sputtering time to 5min and the sputtering temperature to 120℃. After the sputtering is completed, turn off the DC power supply, the heating button and the gas in turn;

[0102] d. Sputtering the middle Ag film. Since the sputtering temperatures of the bottom and top ITO films are not necessarily the same, when the sputtering temperatures are inconsistent, wait for the temperature of the substrate to drop, and then reset the temperature required for sputtering the middle Ag film to 120°C. Introduce the gas required for sputtering again, and the gas parameters used are the same as above. Connect the DC power supply to target B, use the robot to open the baffle, and start sputtering the middle Ag film. The sputtering power is 40W and the sputtering time is 8s;

[0103] e. Sputtering the middle Ni film. Reset the temperature required for sputtering the middle Ni film to 120°C. Introduce the gas required for sputtering again, and the gas parameters used are the same as above. Connect the DC power supply to the C target, use the robot to open the baffle, and start sputtering the middle Ni film. The sputtering power is 40W and the sputtering time is 8s;

[0104] f. Sputtering the top ITO film. After the sputtering of the Ni film is completed, close the baffle, change the target position connected to the DC power supply to target A again, and re-sputter the top ITO film. When sputtering the top ITO film, the sputtering power is 120W. According to the experimental requirements, the sputtering time of the top ITO film is set to 5min. The sputtering temperature and the gas required for sputtering are the same as those when sputtering the bottom ITO film.

[0105] g. After the sputtering of the three layers of film is completed, turn off the DC sputtering power supply, heating power supply, gas inlet valve, pressure regulating valve and molecular pump in turn. When the molecular pump speed drops to 0, close the stop valve and mechanical pump, and finally turn off the main control power supply of the magnetron sputtering machine, and then turn off the chiller.

[0106] Example 2

[0107] 1. The glass substrate prepared in Example 1 of Embodiment 1 was selected, and the multi-layer composite ITO thin film structure prepared by the above preparation method was used. After conducting relevant experiments, it was found that:

[0108] In the experiment, the study found that by changing the thickness parameters of metal and dielectric, exploring the structural morphology and the law of photoelectric performance changes, the thickness of each dielectric layer corresponding to the ITO / Ni / Ag / ITO film with the best performance was obtained: the upper and lower layers of ITO were 50nm, Ni was 4nm, and Ag was 8nm. The average transmittance of the corresponding film was 88.19%, the surface resistance was 6.251Ω / sq, and the quality factor was 1.835×10 -3 Ω -1 At the visible light wavelength λ=550nm, the transmittance of the film is 94.2%.

[0109] The test results show that, whether in a high-temperature oxygen-free or high-temperature oxidizing environment, the addition of the Ni layer allows the film to basically maintain its original excellent photoelectric properties after being treated at 500°C. The stability of the photoelectric properties of the ITO / Ni / Ag / ITO film is much better than that of the ITO / Ag / ITO film. It is a transparent conductive film with excellent photoelectric properties and high stability, and is very suitable for the use of large-size touch display screens. The touch display device of the second embodiment is combined with the glass substrate of the first embodiment to provide excellent basic hardware for large-size touch display screens.

[0110] 2. Comparative Experiment

[0111] Experimental sample: ITO / Ni / Ag / ITO thin film of Example 2

[0112] The same materials and equipment were used to prepare a comparative example ITO / Ag / ITO film.

[0113] (1) When there is no Ag film added, the transmittance of the film is the highest. With the addition of the Ag film, the visible light transmittance decreases. By comparing the transmittance values ​​of different metal thicknesses, it is found that with the increase of the thickness of the intermediate metal layer, the transmittance tends to decrease. This is because the reflection of visible light increases as the metal thickness increases. If the dielectric thickness is too thin, the effect of increasing transmittance and reducing reflection will be greatly weakened. For the same reason, when the Ni layer thickness is small, the thickness of the multilayer thin film dielectric is large, which will affect the transmission of visible light.

[0114] To this end, it was found through experiments that when the thickness of the Ni film is 4nm and the thickness of the Ag film is 8nm, the effect of improving the light transmittance of the film is very significant, and the highest average transmittance of the multilayer film appears at ITO thickness = 50nm, and the average light transmittance of the film at this thickness is 88.19%.

[0115] Based on the test and analysis results, the optimal thickness of each layer of the TIO / Ni / Ag / TIO film is as follows: ITO is 50nm, Ag is 8nm, Ni is 4nm, that is, the thickness of the entire multilayer film is 112nm.

[0116] (2) Ag is the metal with the lowest absorption of visible light among many highly conductive metals and is often used in transparent conductive films. For this reason, this patent also uses Ag as the conductive layer metal. In order to avoid the problem of film usability caused by the instability of Ag performance, this article uses Ni as a barrier layer to prevent the diffusion and oxidation of Ag at high temperature or in an aerobic environment for a long time, which leads to the deterioration of the conductivity of the film.

[0117] (3) The TIO / Ni / Ag / TIO films of Example 2 and Comparative Example were subjected to high temperature treatment in nitrogen and air atmospheres. The treatment temperature range in nitrogen atmosphere was 300-500°C with a temperature gradient of 100°C; the treatment temperature range in air was 300-600°C with a temperature gradient of 100°C. The treatment time was 0.5 h.

[0118] Through XRD diffraction pattern research, it is found that after the comparative example is treated with nitrogen at high temperature, the peak intensity of Ag decreases, the Ag content of the silver layer decreases, and discontinuous and isolated silver islands are formed, resulting in poor crystallinity. In Example 2, the peak intensity of Ag also increases with the increase of temperature. The above phenomena all show that Example 2 obtains better crystallinity at high temperature and the change is not obvious.

[0119] (4) Use a Hall effect tester to test the conductivity of the film and calculate the average transmittance and quality factor of the film

[0120] From the change of surface resistance value, it is found that the conductivity of the comparative example becomes better after heat treatment at 300℃, which is because the crystal quality is improved. However, after the temperature is further increased, the silver layer is oxidized or gradually forms silver islands, resulting in poor crystal quality and decreased film continuity. The surface ITO is also destroyed due to the diffusion of silver and high temperature, forming large holes, which makes the conductivity of the comparative example after high temperature deteriorate significantly. The conductivity of Example 2 reaches the best after treatment at 400℃, and the conductivity is only slightly improved compared with the room temperature sample after the temperature is increased to 500℃.

[0121] In summary, the experiment found that the photoelectric stability of Example 2 in a high-temperature nitrogen environment is better than that of the comparative example, and this is due to the blocking and stabilizing effect of the Ni layer.

[0122] Embodiment 3

[0123] The third embodiment provides a driving control system, which is applied to the touch display screen of the first to second embodiments. The product structure, technical principle and technical effect of the touch display screen are exactly the same as those of the first or second embodiment.

[0124] like Figure 3 As shown, the drive control system is arranged in a touch display screen, and the drive control system is connected to a touch display device of the touch display screen; wherein the drive control system comprises:

[0125] A plurality of channel selectors, wherein the plurality of channel selectors are connected to the touch display device;

[0126] A plurality of operational amplifiers, wherein the plurality of operational amplifiers are connected to the plurality of channel selectors correspondingly;

[0127] At least one ADC digital-to-analog converter, wherein the ADC digital-to-analog converter is connected to the operational amplifier;

[0128] An FPGA controller, wherein the FPGA controller is connected to the operational amplifier;

[0129] A voltage boosting circuit is connected to the FPGA controller, and the voltage boosting circuit is connected to the touch display device.

[0130] In the present invention, for large-size touch screens, manufacturers sometimes reduce the number of channels of the touch screen, which will reduce the touch accuracy. For this reason, the innovative drive control system of this patent innovatively adopts a touch display drive control system based on FPGA chips. FPGA is a digital circuit with a rich number of pins, most of which can be flexibly configured. It is not only suitable for touch screens of different sizes, but also can ensure a higher operating rate and touch accuracy. Since FPGA can execute in parallel and the operating speed can reach 1000MB / S, it can be applied to high-speed circuits. This design uses FPGA as the main control chip of the touch display drive circuit, and applies the charge transfer method to convert charge changes into voltage changes to detect touch.

[0131] Through the design of the present invention, the FPGA controller has the characteristics of parallel execution, the algorithm can be hardwareized, and the touch point recognition and coordinate calculation can be accelerated. It can also achieve 10-point touch on a large-size touch display screen, and the response time is not less than 20ms. In the case of changes in the external electromagnetic environment, the scanning frequency, filter strength and other parameters can be adjusted in real time to improve the recognition rate.

[0132] In a specific implementation, the touch display device of the large-size touch display screen is composed of multiple excitation lines and multiple receiving lines, for example, 41 excitation lines and 72 receiving lines, or 61 excitation lines and 96 receiving lines. This can be designed according to the specific needs of the large-size touch screen, and this application does not limit it.

[0133] Specifically, the transmitting end (TX) of the driving control system corresponds to the number of excitation lines of the touch display device, such as Figure 3 As shown, since the FPGA output voltage is 3.3V, it cannot effectively drive the capacitive screen, and the high level value of the excitation waveform needs to be raised through a voltage boost circuit.

[0134] In the specific implementation of the present invention, based on the considerations of circuit area, power consumption and cost, the receiving end of the drive control system adopts a 9-port ADC digital-to-analog converter to collect 9 columns of data at a time.

[0135] The principle of the present invention is: through time division multiplexing, 96 receiving ends are fully sampled in 12 excitation cycles, that is, the collection of one row of data is realized. FPGA is used to control 12 8-to-1 channel selectors (MUX), and the data of the corresponding columns are periodically received. The corresponding operational amplifiers are also 12 and correspond to the output of MUX one by one. The role of the operational amplifier is to construct a charge transfer circuit, convert the charge change on the capacitive screen into a voltage change, and then sample through the ADC, enter the FPGA controller for subsequent processing and calculation, and obtain the corresponding touch coordinates.

[0136] In the present invention, the FPGA controller includes:

[0137] A data acquisition and peripheral circuit control module, wherein the data acquisition and peripheral circuit control module is respectively connected to the channel selector, the operational amplifier and the ADC digital-to-analog converter; the data acquisition and peripheral circuit control module is also used to generate a row excitation signal and periodically generate an excitation pulse;

[0138] A data processing and touch position search module, which performs filtering processing on the ADC data of the ADC digital-to-analog converter, updates the baseline data, and selects a threshold, and searches and detects the processed data to find out whether there is a touch point;

[0139] A coordinate calculation and reporting module, which is used to calculate the touch point coordinates according to the collected data and the corresponding row and column information, and to package all the calculated touch point coordinates according to a preset protocol and send them through the serial port;

[0140] A main control module, wherein the main control module is respectively connected to the data acquisition and peripheral circuit control module, the data processing and touch position search module and the coordinate calculation and reporting module.

[0141] Each module cooperates with each other to complete the touch detection task of the entire drive control system. The peripheral circuit control module is responsible for data acquisition and control, the data processing module processes and analyzes the acquired data, the coordinate calculation module is responsible for converting the processed data into usable coordinates, and the main control module plays the role of overall control and management of the system and communicates with the host computer. Specifically, the detailed principles and functions of each module are as follows:

[0142] The data acquisition and peripheral circuit control module has two main functions: one is to generate row excitation signals and periodically generate excitation pulses; the other is to complete the control signals of MUX, ADC, and op amp to ensure that each column of data is correctly sampled by the ADC and stored in a certain pattern inside the FPGA for subsequent processing and calculation.

[0143] In a specific implementation, Figure 5 As shown, the data acquisition and peripheral circuit control module consists of a TX excitation generation submodule, a data acquisition and synchronization submodule, an ADC control submodule and a MUX control submodule. Among them, the TX excitation generation submodule generates excitation pulses according to the number of pulses in a row, the period and pulse width of each excitation, and the number of excitation rows. In order to adapt to the changes in the electromagnetic characteristics of the working environment, when the noise monitoring module detects the presence of noise, it will adjust the period and pulse width of the pulse according to a certain rule until the noise is no longer detected. While generating pulses, the TX excitation generation submodule also generates synchronization parameters for synchronizing peripheral modules.

[0144] The data processing and touch position search module also has two main functions: one is to filter the collected ADC data according to the external environment, as well as update the baseline data and select the threshold; the other is to search and detect the processed data to find out whether there is a touch point.

[0145] In the present invention, due to the influence of the working environment and power supply, the collected ADC data needs to be filtered before it can be used by the next level module. According to the noise intensity value monitored by the noise detection module, the sampling interval and the number of samples of the received signal are adjusted, and then the sampled data is digitally filtered to achieve the purpose of reducing noise interference.

[0146] The filtered data is input into the baseline data update module. The baseline data refers to the two-dimensional data plane of the touch array when there is no touch, which is a reference base plane. The scanned sampling data of the new frame is compared with the value of the corresponding position of the baseline, and the difference is taken. The obtained data plane is input into the position search module after the threshold comparison. During the working process, if no touch operation is detected, the baseline is periodically updated to ensure that the baseline corresponds to the current working environment, reduce the false alarm rate and improve the touch accuracy.

[0147] The coordinate calculation and reporting module calculates the coordinates on the LCD system based on the collected data and the corresponding row and column information, and packages all the calculated touch point coordinates in a certain protocol and finally sends them out through the serial port.

[0148] In a specific implementation, after the touch point search is completed in a frame of data, the reported coordinate point is calculated before the next frame comes. The coordinates corresponding to the sensor need to be converted into the spatial coordinates of the touch display device. Specifically, the calculation formula of the coordinate point is:

[0149]

[0150]

[0151] Among them, X n , Y n The total number of data in the X and Y directions in the touch area respectively; n , Y n They are the corresponding coordinates in sensor space; S n is the value of the corresponding position in the sensor space coordinates; R x , R y are the resolution of the touch display device; R tx , Rty are the resolutions of the sensors respectively.

[0152] In the specific implementation, after the calculation is completed, the coordinate points and the corresponding touch serial numbers are stored in the internal RAM for subsequent sending module calls. In order to ensure the effectiveness of data transmission, all touch points in a frame are packaged and output through the serial port.

[0153] The main function of the main control module is to set internal parameters through the serial port, control the status of each module, and send the processed data to the host computer through the serial port for debugging and analysis.

[0154] The drive control system of the present invention has been studied. Through the support of FPGA algorithm and peripheral circuit, the effective data collection and filtering are realized, and the touch area is obtained through the touch position search algorithm. The coordinates in the touch screen reference system are obtained by using the coordinate conversion relationship, and the accuracy meets the requirements. The variable scanning frequency and filtering method are used to improve the anti-interference ability, so that this capacitive touch system can be strong in strong interference and has strong flexibility. The algorithm is implemented through hardware and has high real-time performance. It provides an excellent capacitive touch solution for large-size touch screens.

[0155] For other structures of the touch display screen described in this embodiment, refer to the prior art.

[0156] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A touch display screen, comprising a screen housing, a touch display device arranged on the screen housing, and a drive control system arranged inside the screen housing, wherein the drive control system is connected to the touch display device, and characterized in that: The touch display device includes a glass substrate; the glass substrate is made of the following raw materials: SiO2, Al2O3, B2O3, MgO, CaO, SrO, BaO and SnO2; Among the raw materials of the glass substrate, the weight percentage of SiO2 is 67.24%, the weight percentage of Al2O3 is 12.35%, the weight percentage of B2O3 is 10.30%, the weight percentage of SnO2 is 0.16%, and the sum of the weight percentages of MgO, CaO, SrO and BaO is 9.95%; Wherein, the drive control system comprises: A plurality of channel selectors, wherein the plurality of channel selectors are connected to the touch display device; A plurality of operational amplifiers, wherein the plurality of operational amplifiers are connected to the plurality of channel selectors correspondingly; At least one ADC digital-to-analog converter, wherein the ADC digital-to-analog converter is connected to the operational amplifier; An FPGA controller, wherein the FPGA controller is connected to the operational amplifier; A voltage boosting circuit, wherein the voltage boosting circuit is connected to the FPGA controller, and the voltage boosting circuit is connected to the touch display device; The FPGA controller comprises: A data acquisition and peripheral circuit control module, wherein the data acquisition and peripheral circuit control module is respectively connected to the channel selector, the operational amplifier and the ADC digital-to-analog converter; the data acquisition and peripheral circuit control module is also used to generate a row excitation signal and periodically generate an excitation pulse; A data processing and touch position search module, which performs filtering processing on the ADC data of the ADC digital-to-analog converter, updates the baseline data, and selects a threshold, and searches and detects the processed data to find out whether there is a touch point; A coordinate calculation and reporting module, which is used to calculate the touch point coordinates according to the collected data and the corresponding row and column information, and to package all the calculated touch point coordinates according to a preset protocol and send them through the serial port; A main control module, the main control module is respectively connected to the data acquisition and peripheral circuit control module, the data processing and touch position search module and the coordinate calculation and reporting module; The coordinate calculation and reporting module calculates the coordinate point using the following formula: Among them, X n , Y n The total number of data in the X and Y directions in the touch area respectively; n , Y n They are the corresponding coordinates in sensor space; S n is the value of the corresponding position in the sensor space coordinates; R x , R y are the resolution of the touch display device; R tx , R ty are the resolutions of the sensors respectively.

2. A touch display screen according to claim 1, characterized in that: The glass substrate is prepared by the following preparation method: According to the composition of each raw material of the glass substrate, the batch material is mixed evenly; Add the batch material into a quartz crucible at 1200℃, then heat it up to 1680℃ and keep it warm for 2h. Stir the glass liquid appropriately during the melting process. Then the temperature is lowered to 1560℃, and the glass liquid is introduced into the preheated mold. After cooling to a certain temperature, annealing treatment is carried out. The annealing point temperature is 710℃, and then it is cooled to room temperature at a cooling rate of 2℃ / min.

3. A touch display screen according to claim 2, characterized in that: The touch display device adopts an AMOLED with an On-Cell structure, and the touch display device includes three parts: a cover glass, a touch screen and an AMOLED screen; The touch display device includes a cover glass, a polarizing layer, an ITO layer and an encapsulation glass, an organic material layer, a TFT driving layer and a glass substrate which are sequentially arranged from top to bottom.

4. A touch display screen according to claim 3, characterized in that: The TFT driving layer has a multi-layer composite ITO thin film structure, and the multi-layer composite ITO thin film structure is bonded to the surface of the glass substrate.

5. A touch display screen according to claim 4, characterized in that: The multi-layer composite ITO film structure comprises a bottom ITO film, a middle Ag film, a middle Ni film and a top ITO film.

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