Method for improving color consistency of mini-led display ink

Abstract

The present application relates to the technical field of mini-LED, and particularly relates to a method for improving color consistency of mini-LED display ink, which specifically comprises the following steps: providing a substrate formed with LED chips, and the surface tension of the LED chips is greater than the surface tension of the substrate; immersing the substrate formed with the LED chips in ink; and curing the ink on the substrate. The present application firstly improves the coloring capacity of the ink on the substrate through the difference between the surface tension of the LED chip and the surface tension of the substrate, thereby providing the ink color background required by the mini-LED display, which greatly improves the contrast ratio during the mini-LED display, reduces the proportion of black carbon powder during the encapsulation, thereby reducing the heat generation of the product, and achieving the effect of improving the light efficiency.

Description

[Technical Field]

[0001] This invention relates to the technical field of mini-LEDs, and particularly to a method for improving the color consistency of mini-LED displays. [Background Technology]

[0002] With the continuous improvement of display application technology, the technology of LED full-color display screens is also developing faster and faster. Currently used display application products such as LCD and projection cannot fully meet the application needs of the market. Mini-LED, a new display technology, overcomes many of the shortcomings of the above products and has become the preferred choice for applications in various markets.

[0003] In current chip-on-board (COB) technology, the contrast ratio and black level of the entire display are particularly important aspects. Poor contrast requires adjusting by adding carbon black to the surface through molding. However, adding carbon black through molding directly affects the light emission of the mini-LED chip and increases the heat generation of the entire display panel. [Summary of the Invention]

[0004] To address the issues arising from current mini-LED manufacturing methods that negatively impact the luminous efficacy of mini-LED chips and increase the heat generation of the entire display panel, this invention provides a method for improving the color consistency of mini-LED displays.

[0005] To solve the above-mentioned technical problems, the present invention provides a method for improving the uniformity of ink color in mini-LED displays, comprising the following steps:

[0006] A substrate on which LED chips are formed is provided, wherein the surface tension of the LED chips is greater than the surface tension of the substrate;

[0007] The substrate on which the LED chip is formed is impregnated with ink;

[0008] Ink on the cured substrate.

[0009] Preferably, before the LED chip is formed on the substrate, the surface of the LED chip is treated to make the ratio of the surface tension of the LED chip to the surface tension of the substrate greater than 1.

[0010] Preferably, the surface treatment method includes one or more of surface mirror treatment, laser scanning treatment, and spraying a release agent.

[0011] Preferably, the surface-treated LED chip is formed on the substrate using chip transfer technology.

[0012] Preferably, the method of immersing the substrate on which the LED chip is formed with ink is to wrap the edge of the substrate and inject ink into the surface of the substrate on which the LED chip is formed, or to directly immerse the surface of the substrate on which the LED chip is formed in ink.

[0013] Preferably, the ink has a volume shrinkage rate of 0.5‰ to 10‰, a viscosity of less than 30 CPS, and a dyne value of 30 to 50.

[0014] Preferably, the process includes a step of removing excess ink from the substrate before curing the ink onto the substrate.

[0015] Preferably, excess ink is removed by natural dripping.

[0016] Preferably, after the ink is applied to the substrate, the process further includes a step of cleaning the LED chip.

[0017] Preferably, the LED chip cleaning method is one or more of ultrasonic vibration cleaning and plasma cleaning.

[0018] Compared with existing technologies, the method for improving the ink color consistency of mini-LED displays provided by this invention has the following beneficial effects:

[0019] 1. This invention increases the adhesion of ink to the substrate by utilizing the difference in surface tension between the LED chip and the substrate. This method greatly improves the contrast of mini-LED displays, reduces the proportion of toner required during encapsulation, thereby significantly reducing the heat generated by the product and achieving improved luminous efficiency.

[0020] 2. The present invention processes the LED chip to create a large surface tension difference between its surface tension and that of the substrate, making it easier for ink to adhere to the substrate and less likely to adhere to the chip.

[0021] 3. The LED chip processing method used in this invention can effectively increase the surface tension of the LED chip without damaging it.

[0022] 4. The present invention employs a method of first surface-treating the LED chip and then transferring it onto the substrate, which can effectively reduce damage to the LED chip and prevent the treatment method from affecting the surface tension of the substrate, thereby increasing only the surface tension of the LED chip.

[0023] 5. The ink impregnation method used in this invention utilizes the difference in surface tension between the LED chip and the substrate, making it easier for the ink to adhere to the substrate, resulting in uniform ink filling and convenient operation.

[0024] 6. The ink used in this invention is conducive to adhering to the substrate, and the ink adhering to the LED chip is easy to clean and the ink is minimally affected by volume shrinkage after baking and curing.

[0025] 7. This invention removes excess ink by natural dripping, utilizing the difference in surface tension between the LED chip and the substrate. This reduces uneven ink layer caused by human intervention, reduces ink adhesion to the LED chip, and is easy to operate.

[0026] 8. The present invention cures the ink on the pads where LED chips are formed, which allows the ink to form a film that is beneficial for color development, and at the same time facilitates the cleaning and removal of residual ink on the LED chips.

[0027] 9. When cleaning residues, the ink on the substrate has already solidified, so there is no need to protect the ink layer in the non-LED chip area. Moreover, since the ink's adhesion to the LED chip is much less than its adhesion to the substrate, the residual ink on the chip surface can be easily removed by cleaning. [Attached Image Description]

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art 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.

[0029] Figure 1 This is a flowchart of a method for improving the ink color consistency of mini-LED displays according to the present invention.

[0030] Figure 2 This is a cross-sectional view of the substrate formed by the method of this invention.

[0031] Figure 3 This is a flowchart of the process of forming an LED chip onto a substrate in this invention.

[0032] Figure 4 This is a flowchart of the ink solidified on the substrate in this invention.

[0033] Explanation of reference numerals in the attached diagram:

[0034] 1. A substrate in which LED chips are formed;

[0035] 11. Substrate; 12. LED chip; 13. Solder pad; 14. Ink; 15. Colloid.

Detailed Implementation Methods

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0037] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0038] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0039] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0040] Please see Figure 1 A method for improving the uniformity of ink color in a mini-LED display, provided in a specific embodiment of the present invention, includes the following steps:

[0041] S1. Provide a substrate on which an LED chip is formed, wherein the surface tension of the LED chip is greater than the surface tension of the substrate;

[0042] S2. Immerse the substrate on which the LED chip is formed in the above-mentioned process with ink;

[0043] S3, Ink on the cured substrate.

[0044] Please see Figures 1 to 3 In a specific embodiment of the present invention, the surface tension of the LED chip 12 provided in step S1 is greater than the surface tension of the substrate 11. Specifically, the formation of the surface tension of the LED chip 12 being greater than the surface tension of the substrate 11 includes the following steps:

[0045] S11. Form LED chip 12 on blue film;

[0046] S12. Perform surface treatment on the LED chip 12 on the blue film;

[0047] S13. Transfer the surface-treated LED chip 12 onto the substrate 11.

[0048] Understandably, transferring the LED chip 12 onto the substrate 11 requires connecting the LED chip 12 and the substrate 11 via the pad 13.

[0049] Understandably, forming the LED chip 12 on the blue film can effectively fix the LED chip 12, preventing the machine from missing the LED chip 12 during the transfer process and preventing it from flying onto the pad 13 during the transfer to the substrate 11 and causing failure.

[0050] Understandably, in the method provided by the embodiments of the present invention, in step S12, the LED chip 12 is surface-treated to increase the surface tension of the LED chip 12. Specific methods for increasing the surface tension of the LED chip 12 include, but are not limited to, the following:

[0051] Method 1: By performing laser scanning on the surface of LED chip 12 before it leaves the factory, the surface tension of LED chip 12 is increased, thereby improving its non-sticking ability to ink 14.

[0052] Method 2: Improve the non-sticking ability of LED chip 12 by polishing the surface of LED chip 12 before it leaves the factory to increase the surface tension of LED chip 12;

[0053] Method 3: Spray a layer of release agent on the surface of the LED chip 12 on the blue film before crystal expansion, so as to make the chip easy to clean after it is attached to the ink 14.

[0054] Understandably, in this embodiment of the invention, method three is used, which involves spraying a layer of release agent onto the surface of the LED chip 12 on the blue film before crystal expansion, thereby achieving the effect of easy cleaning of the LED chip 12 after the ink 14 adheres to it.

[0055] Understandably, the present invention requires processing the LED chip 12 before transferring it to the substrate 11. Transferring the LED chip 12 to the substrate 11 before surface treatment may cause the LED chip 12 to fail. At the same time, it may change the surface tension of the substrate 11 and the pads 13, reducing the surface tension difference between the substrate 11 and the pads 13 and the LED chip 12. As a result, the ink 14 is less likely to adhere to the LED chip 12 due to the surface tension difference between the LED chip 12, the pads 13 and the substrate 11, but is more likely to adhere to the pads 13 and the substrate 11.

[0056] Understandably, the ratio of the surface tension of the LED chip 12 to the surface tension of the substrate 11 is greater than 1.

[0057] Understandably, this difference in surface tension can be adjusted to suit different display contrast requirements, depending on the final ink used.

[0058] Please combine Figure 1 and Figure 2 In the method provided by the present invention, the method of impregnating the substrate 1 on which the LED chip is formed with ink 14 in step S2 includes, but is not limited to, the following:

[0059] Method 1: The entire surface of the substrate 1 on which the LED chip is formed is immersed in ink 14. Then, by utilizing the fluidity of the ink 14 itself and the difference in surface tension between the LED chip 12 and the substrate 11, the lower end of the LED chip 12 and the pad 13 on the substrate 11 are coated with ink 14.

[0060] Method 2: First, perform a colloidal dam treatment on the edge of the substrate 1 on which the LED chip is formed, then precisely control the injection of ink 14 into the center of the dam and make it evenly fill the entire substrate.

[0061] Understandably, in this embodiment, when the substrate 1 with LED chips is immersed in ink 14, method two is adopted, namely, first performing colloidal damming treatment on the edges of the substrate 1 with LED chips, then precisely controlling the injection of ink 14 into the center of the dam, and uniformly filling the entire substrate. This invention utilizes the difference in surface tension between the LED chip 12, the substrate 11, and the pads 13, and the principle of capillary action generated by the LED chip 12 being a certain height above the surface of the substrate 11, at which height the ink 14 adheres to the substrate 11 and flows onto the pads 13. Therefore, by controlling the uniformity of the material across the entire surface of the substrate 11 to achieve a uniform effect, the ink 14 can be uniformly filled onto the substrate 11. This consistency monitoring can be controlled through a series of measurement methods such as 3D optical microscopy.

[0062] Understandably, the height of the LED chip 12 above the surface of the substrate 11 in this invention is 20 to 300 μm. Optionally, the height of the LED chip 12 above the surface of the substrate 11 is 20 μm, 90 μm, 160 μm, 230 μm, or 300 μm.

[0063] Specifically, in this embodiment of the invention, the height of the LED chip 12 above the substrate 11 is 30-200 μm. Optionally, in this embodiment of the invention, the height of the LED chip 12 above the substrate 11 is 30 μm, 80 μm, 120 μm, 170 μm, or 200 μm, which can better utilize the principle of capillary action to allow the ink to adhere to the substrate 11.

[0064] Understandably, the ink 14 used in this invention has a volume shrinkage rate of 0.5‰ to 10‰, which is optional. The volume shrinkage rate of the ink 14 is 0.5‰, 3‰, 5.5‰, 7.5‰, or 10‰. The viscosity of the ink 14 is 30 CPS or less, and the dyne value is 30 to 50, with optional dyne values ​​of 30, 35, 40, 45, or 50.

[0065] Specifically, in this embodiment of the invention, the ink 14 used has a volume shrinkage rate of 5‰, a viscosity of 20 CPS or less, and a dyne value of 36 to 42. Optionally, in this embodiment of the invention, the dyne value of the ink 14 used is 36, 39, or 42. The viscosity and dyne value of the ink 14 can be achieved by controlling the operating temperature of the process and other conditions.

[0066] Please see Figure 2 and Figure 4 In the method provided by this embodiment of the invention, the ink 14 on the cured substrate specifically includes the following steps:

[0067] S31. Natural dripping removes excess ink 14;

[0068] S32. Exposure treatment is performed on the substrate 1 with LED chips formed after removing excess ink;

[0069] S33. Baking and curing ink 14 onto substrate 11.

[0070] Understandably, the present invention requires the treatment of excess ink 14 on the substrate 1 on which the LED chip is formed. The present invention treats excess ink 14 by natural dripping, which can ensure that the ink 14 adheres to the substrate 11 and drips onto the pads 13 while reducing the impact of manual removal of ink 14 and damage to the LED chip 12.

[0071] Understandably, in the method provided by this invention, after the ink 14 flows naturally, the substrate 1 on which the LED chip is formed needs to be exposed. The exposure method is UV light irradiation, and the exposure time is 3 to 40 seconds, the purpose of which is to preliminarily shape and cure the ink. Optionally, the exposure time of the ink 14 is 3 seconds, 10 seconds, 17 seconds, 24 seconds, 31 seconds, or 40 seconds.

[0072] Specifically, in this embodiment of the invention, the exposure time by UV light irradiation is 5 to 30 seconds, which allows for better initial setting of the ink. Optionally, in this embodiment of the invention, the exposure time by UV light irradiation is 5 seconds, 15 seconds, or 30 seconds.

[0073] Understandably, in the method provided by this invention, after exposure, the ink 14 on the substrate 1 where the LED chip is formed needs to be cured. The curing process can be performed by baking or air drying. This invention uses baking as the curing method, which reduces the impact of ink 14 flow caused by air drying, and also reduces the curing time, greatly improving curing efficiency.

[0074] Understandably, since ink 14 with a front-to-back volume shrinkage rate of 5‰ is used, the exposure and baking curing steps have little effect on the film formation of ink 14.

[0075] Furthermore, in this embodiment of the invention, after curing the ink 14 on the substrate 11, it is also necessary to remove any remaining ink 14 from the LED chip 12. Therefore, it is necessary to clean the residual ink 14 on the surface of the LED chip 12 on the substrate 11. The cleaning methods include, but are not limited to:

[0076] Method 1: Remove residual ink 14 from the surface of LED chip 12 by plasma cleaning;

[0077] Method 2: Remove residual ink 14 from the surface of LED chip 12 by ultrasonic vibration cleaning;

[0078] In the method provided in this embodiment of the invention, the residual ink 14 on the surface of the LED chip 12 is removed by means of method two, namely by ultrasonic vibration cleaning.

[0079] Furthermore, after cleaning, the substrate 1 with LED chips, which has undergone all the steps, needs to be sealed with colloid 15.

[0080] Understandably, the present invention greatly increases the difference between the surface tension of the LED chip 12 and the surface tension of the substrate 1 by treating the surface of the LED chip 12. This makes the degree of adhesion of the ink 14 to the LED chip 12 and the substrate 11 very different. This difference allows the ink 14 to effectively adhere to the substrate 11 and flow onto the pad 13, but it cannot effectively adhere to the LED chip 12.

[0081] Understandably, when cleaning the surface residue of the LED chip 12 in this invention, no extra protection is required because the ink 14 has different adhesion to the LED chip 12, the substrate 11, and the pads 13, so the surface residue of the LED chip 12 can be easily removed without affecting the adhesion of the ink 14 on the substrate 11 and the pads 13.

[0082] In various embodiments of the present invention, it should be understood that the sequence number of each process does not necessarily imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0083] Compared with existing technologies, the method for improving the ink color consistency of mini-LED displays provided by this invention has the following beneficial effects:

[0084] 1. This invention provides a black background for mini-LED chip displays by utilizing the difference in surface tension between the LED chip and the substrate and pads. This method greatly improves the contrast of mini-LED displays, reduces the proportion of toner required during encapsulation, thereby significantly reducing heat generation and improving luminous efficiency.

[0085] 2. The present invention processes the LED chip to create a large surface tension difference between its surface tension and that of the substrate and pads, making it easier for ink to adhere to the substrate and flow onto the pads, but less likely to adhere to the chip.

[0086] 3. The LED chip processing method used in this invention can effectively increase the tension of the LED chip without damaging it.

[0087] 4. The present invention employs a method of first processing the LED chip and then transferring it onto the substrate, which can effectively reduce damage to the LED chip and prevent the processing method from affecting the surface tension of the substrate and pads, thus increasing only the surface tension of the LED chip.

[0088] 5. The ink impregnation method used in this invention utilizes the difference in surface tension between the LED chip and the substrate and pads, making it easier for the ink to adhere to the substrate and pads, resulting in uniform ink filling and convenient operation.

[0089] 6. The ink used in this invention is conducive to adhering to the substrate, and the ink adhering to the LED chip is easy to clean, and the ink is minimally affected by the volume shrinkage after baking and curing.

[0090] 7. This invention removes excess ink by natural dripping, utilizing the difference in surface tension between the LED chip and the substrate and pads. This reduces uneven ink layer caused by human intervention, reduces ink adhesion to the LED chip, and is easy to operate.

[0091] 8. The present invention cures the ink on the pads where LED chips are formed, which allows the ink to form a film that is beneficial for color development, and at the same time facilitates the cleaning and removal of residual ink on the LED chips.

[0092] 9. When cleaning residues, this invention does not require protection of the ink layer in non-LED chip areas. Since the adhesion of ink on LED chips is much less than that on substrates and pads, residual ink on the chip surface can be easily removed through cleaning.

[0093] The foregoing has provided a detailed description of a method for improving the color consistency of mini-LED displays according to embodiments of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention. Any modifications, equivalent substitutions, and improvements made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for improving color consistency of a mini-LED display, characterized in that, Includes the following steps: A substrate with an LED chip formed thereon is provided. The LED chip is formed on the substrate before the LED chip is formed. The surface treatment of the LED chip makes the adhesion ability of the LED chip less than that of the substrate, so that the ink can adhere to the substrate more easily. The surface treatment method includes one or more of surface mirror treatment, surface laser scanning treatment and spraying release agent. The substrate on which the LED chip is formed is impregnated with ink; Ink on the cured substrate.

2. The method of claim 1, wherein: The LED chip, after undergoing the surface treatment, is formed on the substrate using chip transfer technology.

3. The method of claim 1, wherein: The method of immersing the substrate on which the LED chip is formed with the ink is to wrap the edge of the substrate and inject the ink into the surface of the substrate on which the LED chip is formed, or to directly immerse the surface of the substrate on which the LED chip is formed in the ink.

4. The method of claim 1, wherein: The ink has a volume shrinkage rate of 0.5‰ to 10‰, a viscosity of less than 30 CPS, and a dyne value of 30 to 50.

5. The method of claim 1, wherein: The process includes a step of removing excess ink from the substrate before curing the ink on the substrate.

6. The method of claim 5, wherein: Excess ink is removed by natural dripping.

7. The method of claim 1, wherein: After curing the ink on the substrate, the LED chip is also cleaned.

8. The method of claim 7, wherein: The LED chip cleaning method is one or more of ultrasonic vibration cleaning and plasma cleaning.

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