Display panel maintenance method

Abstract

The invention discloses a display panel maintenance method, and particularly relates to the technical field of display panel maintenance, and the method comprises the steps: enabling a laser beam to act on a display panel through a laser light path, and carrying out the cutting and grooving of a glass substrate or a polaroid on the surface of the display panel; the laser is a purple picosecond pulse laser with the wavelength of 355 nm, the pulse width is smaller than or equal to 20 ps, the power is 6 W, the light beam quality M2 is smaller than 1.3, and the focal length of an objective lens is smaller than or equal to 10 mm. The success rate of display panel maintenance can be greatly improved, the shipment grade of the display panel is improved, and higher economic benefits are obtained.

Description

[0001] This application is a divisional application of a patent application entitled "A Method for Repairing a Display Panel", the original application was filed on November 29, 2024, and the application number is 202411739035.7. Technical Field

[0002] This invention relates to the field of display panel repair technology, and more specifically, to a display panel repair method. Background Technology

[0003] Each pixel in a display panel consists of three sub-pixels (red, green, and blue). Each sub-pixel is controlled by a transistor, which adjusts the current intensity to alter the arrangement of liquid crystal molecules, thereby changing the refractive index and transmittance of light. A short circuit in any transistor or abnormal deflection of liquid crystal molecules will result in a bright spot. Current repair techniques in the display panel industry have significant limitations. Therefore, a new technology is needed to overcome these shortcomings, significantly improve the repair success rate, enhance the quality of LCD panels shipped, and achieve greater economic benefits. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a residential photovoltaic system.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A laser cutting device for repairing display panels, wherein a laser beam acts on the display panel through a laser optical path to cut and groove the glass substrate or polarizer on its surface.

[0007] The laser is a 355nm ultraviolet picosecond pulsed laser with a pulse width ≤20ps, a power of 6W, and a beam quality of M. 2 <1.3, the focal length of the objective lens is ≤10mm.

[0008] In a preferred embodiment, a beam expander, a reflector, a galvanometer, a dichroic mirror, and an objective lens are sequentially arranged in the laser beam path. The laser beam passes through the beam expander, the reflector, the galvanometer, the dichroic mirror, and the objective lens in sequence and acts on the display panel.

[0009] A method for repairing a display panel involves using repair equipment, which includes a CCD optical imaging system, a UV curing unit, a light-shielding material coating unit, an equipment control unit, and a laser unit. The CCD optical imaging system is used to observe the display panel and identify defects. The UV curing unit cures the coated light-shielding material by controlling the UV light intensity and duration. The light-shielding material coating unit controls the material ejection time, the amount ejected per unit time, and the coating path. The laser unit emits a laser to cut grooves on the surface of the glass substrate or polarizer of the display panel.

[0010] The repair of the display panel includes the following steps:

[0011] Step 1, Defect Confirmation: Use the CCD optical imaging system to confirm the location of the defective point on the display panel, as well as the type of the defect, and whether it is a defect that needs to be repaired;

[0012] Step 2, Defect Repair: The laser unit is used to cut and groove the surface of the glass substrate or polarizer at the defect point. Then, the light-shielding material coating unit is used to coat the cut area with light-shielding material. After the coating is completed, the UV curing unit performs light curing treatment on the coated area.

[0013] Step 3, Repair effect confirmation: The effect of the repaired display panel is confirmed by the CCD optical imaging system. If the effect is satisfactory, the next display panel is repaired.

[0014] If the result is unsatisfactory, repeat step two. In a preferred embodiment, the laser unit is the laser cutting device for display panel repair described above.

[0015] In a preferred embodiment, the repair equipment further includes a grinding unit for grinding down the light-shielding material that has cured above the glass surface.

[0016] The technical effects and advantages of this invention are as follows: 1. This invention achieves a low depth-of-focus laser cutting device by reducing the focal length of the front objective lens. During cutting, this keeps the liquid crystal, metal circuitry, ITO film, and other components beneath the glass substrate away from the depth-of-focus range, reducing the impact of the laser, increasing the panel groove depth, and reducing the distance between the coated area and defective points, thereby reducing the area of ​​the coated region. 2. This invention can significantly improve the success rate of display panel repair, improve the shipment grade of display panels, and achieve higher economic benefits. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1a This is an image showing the light-blocking effect of a panel undergoing blackening treatment.

[0019] Figure 1a-1 This is a schematic diagram for ITO blackening repair.

[0020] Figure 1b This is an image showing the light-blocking effect when another panel is blackened.

[0021] Figure 1c This is a schematic diagram of the internal structure of the display panel after Ink repair.

[0022] Figure 1d This is a schematic diagram of a glass substrate for direct coating repair.

[0023] Figure 1e This is a schematic diagram of another glass substrate that is directly coated for repair.

[0024] Figure 1f This is a schematic diagram of light leakage on a glass substrate that is directly coated for repair.

[0025] Figure 1g This is a schematic diagram of light leakage on another glass substrate that has undergone direct coating repair.

[0026] Figure 2 This is a schematic diagram of the laser cutting device of the present invention.

[0027] Figure 3 This is a schematic diagram of the glass substrate surface after being cut by the laser cutting device of the present invention.

[0028] Figure 4 This is a schematic diagram of the glass substrate surface after being cut by a traditional laser device.

[0029] Figure 5 This is a schematic diagram of the repair equipment structure of the present invention.

[0030] Figure 6 This is a schematic diagram showing the processing area of ​​the display panel of the present invention.

[0031] Figure 7 This is a schematic diagram of the coating of the light-shielding material of the present invention.

[0032] Figure 8 This is a schematic diagram of a glass substrate groove repair in one embodiment of the present invention.

[0033] Figure 9 This is a schematic diagram of polarizer slotting and repair in one embodiment of the present invention.

[0034] Figure 10 Figure 1 shows a repair example of the present invention.

[0035] Figure 11 This is a repair example of the present invention. Figure 2 .

[0036] The attached figures are labeled as follows: 1. CCD optical imaging system; 2. UV curing unit; 3. Light-shielding material coating unit; 4. Equipment control unit; 5. Laser unit; 6. Grinding unit. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

[0038] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0039] In related technologies, repair methods for bright spots in LCD panels include BM diffusion repair, ITO blackening repair, and direct coating. BM diffusion repair and ITO blackening repair both aim to transform bright pixels into dark pixels, achieving a light-blocking effect that is difficult to detect macroscopically. Direct coating, on the other hand, does not alter the bright pixels themselves or damage the surface structure of the display panel; it achieves a light-blocking effect through coating.

[0040] Among them, BM diffusion repair uses lasers to break up the BMs around the sub-pixel and cover the sub-pixel, causing it to stop emitting light. With the continuous upgrading of LCD panel products, the BM area between sub-pixels is getting smaller and smaller, and the amount of BMs available to cover the sub-pixel is getting smaller and smaller. As a result, the success rate of this repair technique is getting lower and lower, and its applicability is getting narrower and narrower.

[0041] like Figure 1a-1As shown, ITO blackening repair utilizes laser light to act on the ITO and insulating layer on the TFT side, causing a chemical change in the substances within, thereby achieving pixel blackening and preventing the pixel from emitting light. Changes in the materials used in the ITO and insulating layer, or the material ratios thereof, will cause the blackening process to fail. Therefore, this technology can only be used for specific products and is highly dependent on the products being repaired.

[0042] like Figure 1c As shown, when metal bridges made of tungsten powder or nano-silver materials exist inside the panel due to ink repair during the production process, ITO blackening repair will damage the metal bridges, making ITO blackening repair impossible. Therefore, ITO blackening repair has great limitations in practical applications.

[0043] like Figure 1a One repair method involves laser-burning the panel material above the sub-pixel, blackening the burned area to create a light-blocking region that obscures the light from the sub-pixel, achieving a macroscopically imperceptible effect. However, because the light emitted by the sub-pixel has a certain divergence angle, when only the area equal to the sub-pixel size is treated during the blackening process, light leakage at a certain angle within the side view range of the sub-pixel can occur due to product thickness limitations, making the light-blocking effect less noticeable.

[0044] like Figure 1b One repair method involves laser burning of an area on the panel that far exceeds the area of ​​the sub-pixels, forming a blackened area that effectively blocks light from the sub-pixels. However, this large-scale laser burning process can lead to abnormal energy accumulation, causing damage to the liquid crystal, metal circuitry, and ITO film layer inside the panel.

[0045] The direct coating method involves directly applying a light-shielding material to the display panel area above the defective point to block light. For example... Figure 1d As shown, a coating area is pre-defined on the surface of the glass substrate directly above the defective pixel. This coating area, while covering the light within the divergence angle of the defective pixel, does not affect the display of adjacent pixels. In this case, directly coating the glass substrate surface with a light-shielding material achieves a good light-shielding effect; or as... Figure 1e As shown, when a polarizer is present, a coating area is pre-set on the surface of the glass substrate above the defective pixel. The coating area can cover the light within the divergence angle of the defective pixel without affecting the display of the adjacent pixels of the defective pixel. At this time, a light-shielding material is directly coated on the surface of the glass substrate to achieve a good light-shielding effect.

[0046] However, in practical applications, issues such as the light divergence angle or the thickness of the display panel can cause light leakage at the edges of the light-shielding material; for example... Figure 1fAs shown, a pre-defined coating area is placed on the glass substrate surface above the defective pixel. This coating area, without affecting the display of adjacent pixels of the defective pixel, cannot completely cover the light within the divergence angle of the defective pixel; or as... Figure 1g As shown, a pre-defined coating area is placed on the surface of the polarizer above the defective pixel. The coating area cannot completely cover the light within the divergence angle of the defective pixel without affecting the display of the adjacent pixels.

[0047] As can be seen from the above, BM diffusion repair, ITO blackening repair and direct coating methods all have certain technical defects. Therefore, this invention proposes to use a laser to first thin and groove the defective parts of the panel, and then apply a light-shielding coating to the thinned area to solve the above technical problems.

[0048] The technical challenge of using lasers to thin and groove defective areas on a panel lies in the precise control of the laser. This embodiment provides a laser cutting device for display panel repair, which avoids the defects of the repair methods described above.

[0049] This embodiment provides a laser cutting device for display panel repair, comprising a laser, a beam expander, a reflector, a galvanometer, a dichroic mirror, and an objective lens arranged sequentially. The laser beam is applied to the display panel after passing through the beam expander, reflector, galvanometer, dichroic mirror, and objective lens. Figure 2 As shown. The laser is specifically a 355nm ultraviolet picosecond pulsed laser with a pulse width ≤20ps, a power of 6W, and a beam quality M. 2 <1.3, the focal length of the objective lens is ≤10mm.

[0050] Unlike existing high-focal-length objectives, this objective uses a low-focal-length objective, calculated using the depth-of-focus formula. It can be seen that the depth of focus is proportional to the square of the focal length f of the focusing lens. The larger the focal length f, the greater the depth of focus, the greater the depth of laser action, and the easier it is to damage the metal circuits, films, etc. under the glass substrate.

[0051] Note: M 2 Here, is the laser beam quality factor, is the laser wavelength, f is the focal length of the focusing lens, and D is the diameter of the laser beam before passing through the focusing lens. Within the focal depth range, the shape, size, and energy distribution of the laser spot change very little, which can ensure good processing results.

[0052] Picosecond 355nm ultraviolet lasers are used to thin the display panel, reducing the focal length of the front objective lens to obtain a smaller depth of focus. This keeps the liquid crystal, metal lines, ITO film layer, and other components under the glass substrate away from the depth of focus, reducing the impact of the laser on them and increasing the panel thinning depth.

[0053] A light-shielding material was applied by cutting grooves on the surface of a glass substrate with a thickness of 400 μm. A 355 nm ultraviolet picosecond pulsed laser was used, with a pulse width ≤20 ps, ​​a power of 6 W, and a beam quality of M. 2 <1.3, the laser beam diameter before the objective lens is 5mm, and the focal length of the objective lens is 10mm. Substituting the corresponding data into the depth of focus (DOF) calculation formula, we get a DOF ≈ 4.7µm. The thickness of the glass substrate to be processed is approximately 400µm, meaning the distance from the glass surface to the pixel area and film layers is approximately 400µm. 4.7µm is much smaller than 400µm, resulting in a processing effect as follows: Figure 3 As shown, a 100µm groove is cut. During processing, the laser has minimal impact on the pixel area and film layer on the lower surface of the glass, ensuring the integrity of the components underneath.

[0054] If the objective lens (focusing lens) is replaced with one with a depth of focus (DOF) of 100mm, the DOF will be approximately 470µm. In this case, the DOF is greater than the thickness of the glass substrate (400µm). During processing, the laser will have a significant impact on the pixel area and film layers on the lower surface of the glass, resulting in a processing effect as follows: Figure 4 As shown, the metal circuitry and film layers were clearly damaged.

[0055] This invention provides a method for repairing display panels, which involves using repair equipment, such as... Figure 2 and Figure 5 As shown, the repair equipment includes a CCD optical imaging system, a UV curing unit, a light-shielding material coating unit, an equipment control unit, a grinding unit, and a laser unit. The laser unit is as described above. Figure 2 The laser in the CCD optical imaging system is specifically a camera configured in the optical path of the laser unit. It acquires the light reflected by the objective lens and the dichroic mirror. The optical path received by the camera is equipped with a separate reflector and lens that are distinct from the laser unit. A camera light source is set in the optical path to provide supplementary lighting. The camera acquires the image information of the display panel.

[0056] The specific repair methods include the following:

[0057] The location of the defective point on the display panel is confirmed by the CCD optical imaging system, as well as the type of the defective point and whether it is a defective point that needs to be repaired.

[0058] Using a computer control system, an XY axis is established on the defective surface. The XY axis is used to divide the defective processing area for reduction. The location of the defective processing area is confirmed, and processing marks are made using the computer control system. Figure 6 As shown;

[0059] A computer-controlled galvanometer scans the processing area along the XY axes, maintaining a constant distance between the objective lens and the display panel during the scanning process. A laser unit then cuts and grooves the defective areas on the panel, thinning the area above the defective areas. Finally, a light-shielding material is applied to the thinned areas. Figure 7 As shown;

[0060] Then, UV light curing is used for curing, and the light-blocking material that is higher than the glass surface after curing is ground smooth by a grinding unit; the effect of the repaired display panel is confirmed by a CCD optical imaging system, and if the effect is satisfactory, the next display panel is repaired.

[0061] If the effect is not satisfactory, repeat the cutting, grooving and coating process.

[0062] In another embodiment of the present invention, the laser used for repair is as described above. Figure 2 The laser in the display panel is used to cut and groove the display panel and complete the coating and curing. The display panel includes a sub-pixel in the middle and glass substrates attached to the top and bottom sides of the sub-pixel, as detailed below:

[0063] like Figure 8 As shown, the laser unit emits a laser to cut grooves on the surface of the glass substrate on the light-emitting side of the sub-pixel. The light-shielding material coating unit coats the grooved area of ​​the glass substrate with light-shielding material. UV light cures the coated light-shielding material, and then the coating material is polished. Due to the use of the aforementioned low-depth-of-focus laser, the groove depth can be increased during the cutting process, reducing the distance between the coated area and the defective pixel, thus reducing the area of ​​the coated area. At this point, the light-shielding material can cover the light within the divergence angle of the defective sub-pixel without affecting the display of adjacent sub-pixels, thereby achieving a light-shielding effect that is imperceptible macroscopically.

[0064] In yet another embodiment of the present invention, the laser used for maintenance is as described above. Figure 2 The laser in the display panel is used to cut and groove the display panel and complete the coating and curing. The display panel includes a sub-pixel in the middle, glass substrates attached to the top and bottom sides of the sub-pixel, and a polarizer attached to the side of the glass substrate away from the sub-pixel, as detailed below:

[0065] like Figure 9As shown, the laser unit emits a laser to cut a groove on the surface of the polarizer on the light-emitting side of the sub-pixel. The light-shielding material coating unit coats the grooved area of ​​the polarizer with light-shielding material. UV light cures the coated light-shielding material, and then the coating material is polished. Because a low-depth-of-focus laser is used, the groove depth can be increased during the cutting process, reducing the distance between the coated area and the defective pixel, thereby reducing the area of ​​the coated area. At this point, the light-shielding material can cover the light within the divergence angle of the defective sub-pixel without affecting the display of neighboring sub-pixels, thus achieving a light-shielding effect that is imperceptible macroscopically.

[0066] Based on the above repair methods, after repairing the defective points on the display panel, take a picture of the side of the display panel where the pixels emit light, such as... Figure 10 As shown, the poorly observed pixels are covered by light-blocking material to achieve a light-blocking effect, making them imperceptible on a macroscopic scale.

[0067] Based on the above repair method, after repairing the defects in the display panel, the images acquired on both sides of the light source of the display panel are as follows: Figure 11 As shown, the front light is an image of the back side of the display panel pixels emitting light, while the back light is an image of the front side of the display panel pixels emitting light. By cutting and coating the light-shielding material, the light-shielding effect of defective points can be achieved without affecting the normal display of adjacent pixels.

[0068] In summary, by using the laser cutting device and display panel repair method provided by this invention, the success rate of repairing defective parts of the panel can be greatly improved, the shipment grade of the display panel can be upgraded, and higher economic benefits can be obtained.

[0069] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described and explained in the present invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A method for repairing a display panel, comprising repairing it using repair equipment, characterized in that, The repair equipment includes a CCD optical imaging system, a UV curing unit, a light-shielding material coating unit, an equipment control unit, and a laser unit. The CCD optical imaging system is used to observe the display panel and identify defects. The UV curing unit cures the coated light-shielding material by controlling the UV light intensity and duration. The light-shielding material coating unit controls the material ejection time, the amount ejected per unit time, and the coating path. The laser unit emits a laser to cut and groove the surface of the glass substrate or polarizer of the display panel. The laser unit is a laser cutting device for display panel repair. The laser beam acts on the display panel through a laser optical path to cut and groove the surface of the glass substrate or polarizer. The laser is a 355nm ultraviolet picosecond pulsed laser with a pulse width ≤20ps, a power of 6W, and a beam quality M. 2 <1.3, the focal length of the objective lens is ≤10mm; a beam expander, a reflector, a galvanometer, a dichroic mirror and an objective lens are arranged in sequence on the laser beam path, and the laser beam passes through the beam expander, the reflector, the galvanometer, the dichroic mirror and the objective lens in sequence to act on the display panel; The repair of the display panel includes the following steps: Step 1, Defect Confirmation: Use the CCD optical imaging system to confirm the location of the defective point on the display panel, as well as the type of the defect, and whether it is a defect that needs to be repaired; Step 2, Defect Repair: The laser unit is used to cut and groove the surface of the glass substrate or polarizer at the defect point. Then, the light-shielding material coating unit is used to coat the cut area with light-shielding material. After the coating is completed, the UV curing unit performs light curing treatment on the coated area. Step 3, Repair effect confirmation: The effect of the repaired display panel is confirmed by the CCD optical imaging system. If the effect is satisfactory, the next display panel is repaired. If the result is unsatisfactory, repeat step two.

2. The display panel repair method according to claim 1, characterized in that, The maintenance equipment also includes a grinding unit, used to grind down the light-shielding material that has cured above the glass surface.

3. A method for repairing a display panel according to claim 1, characterized in that, The CCD optical imaging system specifically comprises a camera configured in the optical path of the laser unit. It acquires the light reflected from the objective lens and dichroic mirror. The optical path received by the camera is separately equipped with a reflector and lens that are distinct from the laser unit. A camera light source is also set in the optical path for supplementary lighting. The camera acquires image information of the display panel.

4. A method for repairing a display panel according to claim 1, characterized in that, Using a computer control system, an XY axis is established on the surface of the defective points. The defective point processing area is divided by the XY axis, the location of the defective point processing area is confirmed, and the processing mark is made by the computer control system.

5. A method for repairing a display panel according to claim 1, characterized in that, Using a computer control system, the galvanometer is scanned along the XY axis in the processing area plane, maintaining the distance between the objective lens and the display panel during the scanning process.

6. A method for repairing a display panel according to claim 1, characterized in that, The laser unit emits a laser to cut grooves on the surface of the glass substrate on the side of the sub-pixel that emits light. The light-shielding material coating unit coats the grooved area of ​​the glass substrate with light-shielding material. UV light cures the coated light-shielding material.

7. A method for repairing a display panel according to claim 1, characterized in that, The laser unit emits a laser to cut grooves on the surface of the polarizer on the light-emitting side of the sub-pixel. The light-shielding material coating unit coats the grooved area of ​​the polarizer with light-shielding material. UV light cures the coated light-shielding material.

8. A method for repairing a display panel according to claim 1, characterized in that, The light-blocking material can cover the light within the divergence angle of the defective pixel without affecting the display of the adjacent pixels of the defective pixel.

9. A method for repairing a display panel according to claim 1, characterized in that, The confirmation of repair results includes taking photos on the side of the display panel where the pixels emit light, and observing that the defective pixels are covered by light-blocking material.

10. A method for repairing a display panel according to claim 9, characterized in that, Confirmation of repair effectiveness also includes: The images are taken from both sides of the light source of the display panel. The front light image is the image of the back side of the display panel pixels emitting light, while the back light image is the image of the front side of the display panel pixels emitting light.

Images