Cleaning method for small piece of display glass

Abstract

The invention discloses a method for cleaning small pieces of display glass. The method comprises a substrate cutting step, a grinding treatment step, a water washing treatment step, a drying treatment step and a detection and sorting step. The cleaning method is used for removing glass residues and hard foreign matters on the edge and the surface of the small piece of display glass.

Description

Technical Field

[0001] The present invention relates to display screen manufacturing technology, and particularly to a cleaning method for small-piece display glass. Background Art

[0002] With the popularization of smart wearable devices, the requirements for the cleanliness and surface quality of display screens are increasing day by day. During the manufacturing process of display screens, large-sized glass substrates need to be cut into small-piece display glass to fit wearable devices. However, glass residues, hard foreign objects, and edge burrs generated after cutting will significantly affect the display effect and product life. Traditional cleaning methods such as manual wiping and ordinary water washing have problems such as incomplete cleaning and difficulty in removing tiny glass debris and stubborn foreign objects. Summary of the Invention

[0003] In order to solve the above-mentioned deficiencies of the prior art, the present invention provides a cleaning method for removing glass residues and hard foreign objects on the edges and surfaces of small-piece display glass.

[0004] The technical problems to be solved by the present invention are achieved through the following technical solutions: A cleaning method for small-piece display glass, comprising the following steps: Substrate cutting: cutting a large-sized glass substrate into small-piece display glass of the required size; Grinding treatment: fixing the cut small-piece display glass in a grinding device, and grinding the edges and surfaces of the small-piece display glass through a grinding disc, wherein the grinding pressure is controlled within the range of 0.5 - 1.2 MPa, the grinding speed is 200 - 400 rpm, and the grinding time is 15 - 20 seconds; Water washing treatment: transferring the ground small-piece display glass to a water washing device, and cleaning it by spraying and / or soaking, wherein the water washing medium is deionized water or pure water, the water washing temperature is 25 - 40 °C, the spraying pressure is 0.3 - 0.8 MPa, and the soaking time is 3 - 5 minutes; Drying treatment: removing the surface moisture of the washed small-piece display glass by hot air drying and / or infrared drying, wherein the hot air temperature is 50 - 70 °C, the wind speed is 2 - 5 m / s, the drying time is 5 - 10 minutes, the infrared drying power is 500 - 800 W, and the drying time is 3 - 8 minutes; Inspection and sorting: optically inspecting the dried small-piece display glass to remove defective products with excessive surface residual foreign objects or scratches, and enabling qualified products to enter the subsequent assembly process.

[0005] Further, the grinding device includes a grinding head with adjustable pressure, a driving unit with controllable rotational speed, and an automatic positioning fixture. The driving unit is connected to the grinding disc through the grinding head to drive the grinding disc to rotate. The grinding head is used to adjust the pressure of the grinding disc on the small-piece display glass, and the automatic positioning fixture is used to clamp and adjust the clamping position of the small-piece display glass to ensure the uniform contact between the grinding disc and the edge and surface of the small-piece display glass.

[0006] Further, in the water washing treatment step, a cleaning agent is added to assist in cleaning. The cleaning agent includes a surfactant with a mass fraction of 0.5% - 2% and a chelating agent with a mass fraction of 0.1% - 0.5%. The surfactant is selected from at least one of sodium dodecyl sulfate and polyoxyethylene ether, and the chelating agent is selected from disodium ethylenediaminetetraacetate or sodium citrate.

[0007] Further, the pH value of the cleaning agent is 6.5 - 7.5.

[0008] Further, the water washing device includes an ultrasonic generator with an ultrasonic frequency of 28 - 40 kHz.

[0009] Further, the spraying method uses a multi-angle rotating nozzle, and the spraying coverage range is the entire surface and edge of the small-piece display glass.

[0010] Further, in the drying treatment step, hot air drying and infrared drying are carried out alternately. First, hot air drying is used to remove most of the moisture, and then infrared drying is used to complete fine dehydration.

[0011] Further, the grinding disc is a diamond-coated grinding disc or a ceramic grinding disc, and its surface roughness Ra ≤ 0.1 μm.

[0012] Further, in the detection and sorting step, a high-resolution CCD camera is used to optically detect the dried small-piece display glass pieces, with a detection accuracy of ±5 μm, and it is linked with an automatic sorting device to immediately reject unqualified products.

[0013] Further, between the substrate cutting step and the grinding treatment step, the cleaning method further includes: Pre-cleaning treatment: Compressed air or negative pressure adsorption is used to remove the loose residues on the surface of the small-piece display glass.

[0014] The present invention has the following beneficial effects: The cleaning method of the present invention uses a combination of grinding and water washing to clean the edges and surfaces of the small-sized display glass after cutting, so as to remove glass residues and hard foreign matters. Through precise parameter control, the grinding pressure is controlled within the range of 0.5 - 1.2 MPa, the grinding speed is 200 - 400 rpm, the grinding time is 15 - 20 seconds, the water washing temperature is 25 - 40 °C, the spraying pressure is 0.3 - 0.8 MPa, and the soaking time is 3 - 5 minutes. It can completely remove glass residues and hard foreign matters. After removing the glass residues and hard foreign matters, the small-sized display glass is dried and inspected and sorted to eliminate defective products with foreign matters remaining on the surface or scratches exceeding the standard. Finally, the qualified products enter the subsequent assembly process, improving the assembly yield. Description of the Drawings

[0015] Figure 1 It is a block diagram of the steps of the cleaning method provided by the present invention.

[0016] Figure 2 It is a block diagram of the steps of another cleaning method provided by the present invention. Detailed Embodiments

[0017] The present invention will be described in detail below with reference to the drawings and embodiments. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0018] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

[0019] In addition, the terms "first", "second", "third" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", "third" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0020] In the present invention, unless otherwise clearly specified and defined, terms such as "installation", "connection", "linkage", "fixation", "setting", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and can also be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] Example 1 As Figure 1 shown, a cleaning method for small-piece display glass includes the following steps: Substrate cutting: cutting a large-sized glass substrate into small-piece display glass of the required size; Grinding treatment: fixing the cut small-piece display glass in a grinding device, and grinding the edge and surface of the small-piece display glass through a grinding disc. Among them, the grinding pressure is controlled within the range of 0.5 - 1.2 MPa, the grinding speed is 200 - 400 rpm, and the grinding time is 15 - 20 seconds; Water washing treatment: transferring the ground small-piece display glass to a water washing device, and cleaning it by spraying and / or soaking. Among them, the water washing medium is deionized water or pure water, the water washing temperature is 25 - 40 °C, the spraying pressure is 0.3 - 0.8 MPa, and the soaking time is 3 - 5 minutes; Drying treatment: removing the surface moisture of the washed small-piece display glass through hot air drying and / or infrared drying. Among them, the hot air temperature is 50 - 70 °C, the wind speed is 2 - 5 m / s, the drying time is 5 - 10 minutes, the infrared drying power is 500 - 800 W, and the drying time is 3 - 8 minutes; Inspection and sorting: optically inspecting the dried small-piece display glass to eliminate defective products with surface residual foreign matters or scratches exceeding the standard, so that qualified products enter the subsequent assembly process.

[0022] The cleaning method of the present invention uses a combination of grinding and water washing to clean the edge and surface of the cut small-piece display glass to remove glass residues and hard foreign matters. Through precise parameter control, the grinding pressure is controlled within the range of 0.5 - 1.2 MPa, the grinding speed is 200 - 400 rpm, the grinding time is 15 - 20 seconds, the water washing temperature is 25 - 40 °C, the spraying pressure is 0.3 - 0.8 MPa, and the soaking time is 3 - 5 minutes. It can completely remove glass residues and hard foreign matters. After removing the glass residues and hard foreign matters, the small-piece display glass is dried and inspected and sorted to eliminate defective products with surface residual foreign matters or scratches exceeding the standard. Finally, qualified products enter the subsequent assembly process to improve the assembly yield.

[0023] In some examples, the grinding device includes a grinding head with adjustable pressure, a drive unit with controllable rotational speed, and an automatic positioning fixture. The drive unit is connected to the grinding disc through the grinding head to drive the grinding disc to rotate. The grinding head is used to adjust the pressure of the grinding disc on the small-piece display glass, and the automatic positioning fixture is used to clamp and adjust the clamping position of the small-piece display glass.

[0024] The cleaning method of the present invention uses a grinding head with adjustable pressure to connect the drive unit and the grinding disc, so as to adjust the grinding pressure of the grinding disc on the small-piece display glass through the grinding head, thereby ensuring the contact uniformity between the grinding disc and the edge and surface of the small-piece display glass, and improving the grinding uniformity of the small-piece display glass.

[0025] In this embodiment, the grinding disc is a diamond-coated grinding disc or a ceramic grinding disc, and its surface roughness Ra ≤ 0.1 μm.

[0026] In some examples, in the water washing treatment step, a cleaning agent is added to assist in cleaning. The cleaning agent includes a surfactant with a mass fraction of 0.5% - 2% and a chelating agent with a mass fraction of 0.1% - 0.5%. The surfactant is selected from at least one of sodium dodecyl sulfate and polyoxyethylene ether, and the chelating agent is selected from disodium ethylenediaminetetraacetate or sodium citrate.

[0027] In the water washing treatment step of the cleaning method of the present invention, cleaning is assisted by adding the cleaning agent to improve the cleaning effect. The surfactant reduces the surface tension of water and enhances the penetration and peeling ability of residues, hard foreign matters, and oil stains on the small-piece display glass. Among them, sodium dodecyl sulfate (anionic type) provides strong detergency, while polyoxyethylene ether (non-ionic type) improves the dispersibility of complex stains. The two work together to ensure the thorough removal of stubborn foreign matters. The chelating agent such as disodium ethylenediaminetetraacetate (EDTA-2Na) or sodium citrate can efficiently bind metal ions such as calcium and magnesium in water, prevent them from combining with dirt to form secondary deposits, reduce the remaining surface white spots or water stains, and keep the small-piece display glass after cleaning with high light transmittance. In addition, the non-ionic property of polyoxyethylene ether is mild and non-corrosive, which can avoid damage to the surface coating or circuit caused by traditional strong acid / alkali cleaning agents; sodium citrate is a biodegradable material, with better environmental protection than EDTA, and at the same time controls the pH value in the neutral range of 6.5 - 7.5, further preventing coating oxidation or circuit corrosion.

[0028] Preferably, the pH value of the cleaning agent is 6.5 - 7.5.

[0029] In some examples, the water washing device includes an ultrasonic generator with an ultrasonic frequency of 28 - 40 kHz.

[0030] In the cleaning method of the present invention, ultrasonic cleaning is combined in the water washing treatment step, which can enhance the peeling effect of the cleaning agent on the glass residues and hard foreign matters on the small piece of display glass.

[0031] In some examples, the spraying method uses a multi - angle rotating nozzle, and the spraying coverage range is the entire surface and edges of the small piece of display glass.

[0032] The multi - angle rotating nozzle forms a three - dimensional cleaning path by dynamically adjusting the spraying direction (adjustable from 0 - 90°), ensuring that the edges, corners, and curved surface areas of the lower piece of display glass are evenly covered, and reducing the residue problem caused by spraying blind spots. Moreover, the centrifugal diffusion effect during the rotation of the nozzle atomizes the cleaning agent into micron - sized droplets (particle size 10 - 50μm), increasing the contact area with the glass residues and hard foreign matters, and enhancing the penetration and dissolution ability.

[0033] In some examples, in the drying treatment step, hot air drying and infrared drying are carried out alternately. First, hot air drying is used to remove most of the moisture, and then infrared drying is used to complete fine dehydration.

[0034] Hot air drying can quickly evaporate the surface and shallow - layer moisture (about 80% - 90%) of the small piece of display glass through a high - speed air flow (2 - 5 m / s), significantly shortening the overall drying time; subsequently, infrared drying (500 - 800 W) precisely radiates and heats the deep - layer residual moisture of the small piece of display glass, and uses its penetrability to directly act on the molecular bonds to completely remove the bound water; the combination of the two makes the total drying time shorter and the energy consumption lower than that of a single method. For example, 6 minutes of hot air drying + 4 minutes of infrared drying, and the total energy consumption is reduced by 35% compared with single infrared drying. The hot air temperature (50 - 70°C) is controlled within the tolerance range of the coating or circuit on the surface of the lower piece of display glass to avoid thermal stress cracks or coating peeling caused by high temperature; infrared drying uses short - wave radiation (wavelength 2 - 5μm), and the energy is concentrated at the water absorption peak, reducing the over - heating of the lower piece of display glass and its surface coating or circuit.

[0035] In addition, the trace amount of moisture (10% - 20%) remaining after hot air drying is targeted for removal by infrared drying to avoid water stain crystallization or local oxidation. The infrared power is dynamically adjusted (for example, when the power is 750 W, the radiation depth reaches 0.5 mm) to ensure the complete drying of the micropores and edge gaps of the small piece of display glass.

[0036] In some examples, in the detection and sorting step, a high-resolution CCD camera is used to optically detect the dried small display glass pieces, with a detection accuracy of ±5 μm, and it is linked with an automatic sorting device to reject unqualified products in real time.

[0037] The high-resolution CCD camera (50 million pixels) combined with a coaxial light source can identify foreign matter residues, scratches or coating defects with a size ≥5 μm, and the detection accuracy reaches ±5 μm. Then, three-dimensional modeling of the surface topography is carried out through image algorithms (such as edge detection and gray-scale contrast) to reduce the missed detection rate and misjudgment rate, ensuring that only qualified products (foreign matter ≤20 μm, scratch depth ≤5 μm) enter the subsequent processes, thereby improving the product yield. The detection results are transmitted to the sorting robotic arm (six-axis robot) in real time to achieve seamless connection of "detection-sorting-recording" and improve the efficiency of detection and sorting.

[0038] In the cleaning method of the present invention, all steps are completed through the linkage of an automatic control system. The control system includes a PLC controller and a human-machine interface, which are used for parameter setting, process monitoring and abnormal alarm.

[0039] Example Two As an optimized solution of Example One, in this example, as Figure 2 shown, between the substrate cutting step and the grinding treatment step of the cleaning method, it further includes: Pre-cleaning treatment: Compressed air or negative pressure adsorption is used to remove the loose residues on the surface of the small display glass.

[0040] Before the grinding treatment step of the cleaning method of the present invention, loose residues (such as glass debris and dust) on the surface of the small display glass are removed in advance by compressed air (pressure 0.3-0.6 MPa) or negative pressure adsorption (vacuum degree ≥0.08 MPa), which can reduce the load of subsequent grinding and water washing steps. The pre-cleaning does not require chemical reagents and only relies on physical effects, with low resource consumption. After reducing the load of subsequent grinding and water washing steps, the overall consumption of water and electricity resources can be reduced, and it is more environmentally friendly; at the same time, it can also avoid the risk that larger-sized loose residues are pressed into the surface of the small display glass to form scratches during the grinding process, and can also improve the service life of the grinding disc.

[0041] Among them, for compressed air: It is directionally blown through a multi-nozzle array (coverage accuracy ±0.5 mm), and key cleaning is carried out for areas prone to residue such as edges and holes, and the residue removal rate ≥95%; for negative pressure adsorption: A micro-suction nozzle (aperture 0.5-1 mm) is used in combination with a flexible sealing ring to adapt to curved and shaped display screens, and the adsorption efficiency reaches 98%, avoiding residue scattering and environmental pollution.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention and are not intended to limit them. Although the embodiments of the present invention have been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the embodiments of the present invention can still be modified or equivalently replaced, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for cleaning a small piece of display glass, characterized in that: The steps include: Substrate cutting: Cutting large glass substrates into small pieces of display glass of required size; Grinding treatment: fixing the cut small piece of display glass in a grinding device, and grinding the edge and surface of the small piece of display glass by a grinding disc, wherein the grinding pressure is controlled within the range of 0.5-1.2 MPa, the grinding speed is 200-400 rpm, and the grinding time is 15-20 seconds; Water washing treatment: the ground small pieces of display glass are transferred to a water washing device and washed by spraying and / or immersion, wherein the water washing medium is deionized water or purified water, the water washing temperature is 25-40°C, the spraying pressure is 0.3-0.8MPa, and the immersion time is 3-5 minutes; Drying treatment: The cleaned small display glass pieces are dried by hot air and / or infrared drying to remove surface moisture, wherein the hot air temperature is 50-70°C, the wind speed is 2-5m / s, the drying time is 5-10 minutes, and the infrared drying power is 500-800W, and the drying time is 3-8 minutes; Inspection and sorting: The dried small pieces of display glass are optically inspected to remove defective products with residual foreign matter or excessive scratches on the surface, so that qualified products can enter the subsequent assembly process.

2. The cleaning method according to claim 1, characterized in that: The grinding device includes a grinding head with adjustable pressure, a driving unit with controllable speed, and an automatic positioning fixture. The driving unit is connected to the grinding disc through the grinding head, thereby driving the grinding disc to rotate; the grinding head is used to adjust the pressure of the grinding disc on the small piece of display glass, and the automatic positioning fixture is used to clamp and adjust the clamping position of the small piece of display glass to ensure the uniformity of contact between the grinding disc and the edge and surface of the small piece of display glass.

3. The cleaning method according to claim 1, characterized in that: In the water washing step, a cleaning agent is added to assist cleaning, and the cleaning agent includes a surfactant with a mass fraction of 0.5%-2% and a chelating agent with a mass fraction of 0.1%-0.5%, the surfactant is selected from at least one of sodium lauryl sulfate and polyoxyethylene ether, and the chelating agent is selected from disodium ethylenediaminetetraacetic acid or sodium citrate.

4. The cleaning method according to claim 3, characterized in that: The pH value of the cleaning agent is 6.5-7.

5.

5. The cleaning method according to claim 3, characterized in that: The water washing device comprises an ultrasonic generator, and the ultrasonic frequency is 28-40kHz.

6. The cleaning method according to claim 1, characterized in that: The spraying method adopts a multi-angle rotating nozzle, and the spraying coverage range is the entire surface and edge of the small piece of display glass.

7. The cleaning method according to claim 1, characterized in that: In the drying process, hot air drying and infrared drying are performed alternately, firstly hot air drying is used to remove most of the moisture, and then infrared drying is used to complete the fine dehydration.

8. The cleaning method according to claim 1, characterized in that: The grinding disc is a diamond-coated grinding disc or a ceramic grinding disc, and its surface roughness Ra≤0.1 μm.

9. The cleaning method according to claim 1, characterized in that: In the detection and sorting step, a high-resolution CCD camera is used to perform optical detection on the dried small display glass pieces, with a detection accuracy of ±5 μm, and the camera is linked with an automatic sorting device to remove unqualified products in real time.

10. The cleaning method according to claim 1, characterized in that: The cleaning method further comprises, between the substrate cutting step and the grinding step: Pre-cleaning treatment: using compressed air or negative pressure adsorption to remove loose residues on the surface of the small piece of display glass.

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