WO2022148267A1

WO2022148267A1 - Ink color printing method for led display screen, and display module

Info

Publication number: WO2022148267A1
Application number: PCT/CN2021/141868
Authority: WO
Inventors: 王朝; 朱卫强
Original assignee: 深圳市洲明科技股份有限公司
Priority date: 2021-01-07
Filing date: 2021-12-28
Publication date: 2022-07-14
Also published as: CN114745863A

Abstract

An ink color printing method for an LED display screen. Two ink layers are printed on an LED display screen module to form a solder mask (2') and a backlight layer (1'); the solder mask (2') ink is printed at positions, outside areas having a preset distance from pads (3'), on a lamp surface, and only has a function of protecting the edges of the pads (3'); the backlight layer (1') ink is printed at positions, corresponding to gaps (4') between different lamp beads (5'), on the side of the solder mask (2') distant from the lamp surface, and only has a backlight function. Thus, the ink color consistency of the LED display screen is improved, and the backlight effect of the LED display screen is greatly improved, thereby improving the quality of the LED display screen.

Description

LED display ink printing method and display module

This application claims the priority of the Chinese patent application with the application number 202110016200.6 and the title of "Ink Color Printing Method for LED Display Screen" filed on January 7, 2021, the entire contents of which are incorporated into this application by reference.

technical field

The invention relates to the field of LED display screens, in particular to an ink color printing method for LED display screens and a display module.

Background technique

The LED (Light Emitting Diode) display is used as a display panel, and the consistency of the backlight of the screen is particularly important, which directly determines the quality of the screen. However, as a surface mount LED display module, the substrate of the circuit board copper clad laminate itself will have a certain color difference. Usually, the industry will use black solder mask ink (solder mask) to alleviate this problem, but the solder mask ink In order to ensure the edge accuracy of the pad, its thickness is extremely thin, and it is also volatile during processing. In the specific processing process, the ink is brushed on the lamp board through a stencil, even if it is on the same board in the same batch, the first brushing and the second brushing are due to the different time intervals, resulting in Part of the volatilization of the ink makes the concentration of the solder mask ink inconsistent. After the processing is completed, the ink color is inconsistent. The cost of controlling the consistency of the ink is very high, and it is usually difficult to guarantee.

For the LED display, the screen can display black, and the ink color of the back plate occupies a large part of the credit. When the screen body is not emitting light, the structure itself is black, so the better the black effect of the screen body backlight, the better the screen. The better the quality of the volume, the higher the contrast of the display.

There are two indicators for judging the black effect of the backlight, one is the consistency of ink color, and the other is how far its chromaticity is from true black. The priority of ink color consistency is higher than that of ink color chromaticity. Neither indicator can be effectively guaranteed.

For LED display modules, the black backlight mainly comes from a layer of solder mask sprayed on the lamp surface. The solder mask should expose the pad position of the lamp bead. The size of the lamp bead is very small, so the pad is very small. To ensure that the pad can not be covered by the solder mask, it is necessary to ensure that the solder mask itself is also very thin. If the solder mask layer is too thin, the difference in its distribution concentration will be particularly obvious, just like a layer of window paper, through the sunlight, the inner fiber density can be seen clearly, which is directly reflected on the module, that is The ink colors of the modules are inconsistent.

For modules, the ink color inconsistency is further classified. The ink color of a single module is inconsistent, the ink color of the module on the whole screen is inconsistent, and the ink color of two different screens is inconsistent. Consistency, the prior art regulates and constrains the batch number of the display module by controlling the production batch of the display module. Modules with different batch numbers should not be installed on the same screen to ensure the screen The modules used in the above are all in the same batch, and there will also be cases where different batches of modules are shipped to the site and can only be used reluctantly, failing to solve the problem from the root cause. The smaller the module is, the more prominent the ink color problem of the module is. There is no feasible solution for the inconsistent ink color of the entire screen module in the same batch and the inconsistent ink color of different areas on a single module. Set aside.

SUMMARY OF THE INVENTION

The invention provides an ink color printing method for an LED display screen, comprising the steps of:

Printing ink on the lamp surface of the display module of the LED display screen outside the area of the first preset distance from the pad to form a solder mask;

Ink is printed on the side of the solder resist layer away from the lamp surface of the display module at a position corresponding to the gap between different lamp beads to form a backlight layer.

The present invention also provides a display module, comprising:

The solder resist layer is located outside the area of the lamp surface of the display module that is the first preset distance from the pad;

The backlight layer is located on the side of the solder resist layer away from the lamp surface of the display module, and at least corresponds to the gap between the lamp beads, and the thickness of the backlight layer is greater than the thickness of the solder resist layer.

The details of various embodiments of the invention are set forth in the accompanying drawings and the description below. Those skilled in the art will easily understand other features, problems to be solved, and beneficial effects of the present invention from the description, drawings, and claims.

Description of drawings

In order to better describe and illustrate the embodiments of the present application, reference may be made to one or more drawings, but the additional details or examples used to describe the drawings should not be considered as invention-creations, presently described implementations of the present application A limitation of the scope of any one of the examples or preferred modes.

1 is a flow chart of steps in a method for ink color printing on an LED display screen according to an embodiment of the present invention;

2 is a schematic diagram of ink printing of a display module in an ink color printing method for an LED display screen according to an embodiment of the present invention;

3 is a schematic diagram of a black level in the ink color printing method for an LED display screen according to an embodiment of the present invention;

4 is a schematic diagram of dividing a sub-region of a solder resist layer into 4 code bit regions in an ink color printing method for an LED display screen according to an embodiment of the present invention;

5 is a schematic diagram of dividing a display module into 4 code-bit areas in a method for ink color printing on an LED display screen according to an embodiment of the present invention;

6 is a schematic diagram of dividing a sub-region of a solder resist layer into 20 code-bit regions in an ink color printing method for an LED display screen according to an embodiment of the present invention;

7 is a schematic diagram of dividing a display module into 20 code-bit areas in the ink color printing method for an LED display screen according to an embodiment of the present invention;

8 is a schematic diagram of the splicing of different display modules in the ink color printing method for an LED display screen according to an embodiment of the present invention;

9 is a schematic diagram of a printing effect based on a pseudo-random sequence in an ink color printing method for an LED display screen according to an embodiment of the present invention.

Detailed ways

In order to describe in detail the technical content, achieved objects and effects of the present invention, the following descriptions are given with reference to the embodiments and the accompanying drawings.

As shown in FIG. 1 , an embodiment of the present invention provides a method for ink color printing on an LED display screen, including the steps:

It can be seen from the above description that the beneficial effect of the present invention is: by printing two layers of ink on the LED display module, the solder mask layer and the backlight layer are formed, and the solder mask layer ink is on the lamp surface outside the area of the preset distance from the pad. Position printing only protects the edge of the pad, and the backlight layer ink is printed on the side of the solder mask away from the lamp surface corresponding to the gap between different lamp beads, which only plays the role of backlight, thus improving the LED display. The consistency of the ink color of the screen greatly improves the backlight effect of the LED display, thereby improving the quality of the LED display.

Further, printing ink on the side of the solder resist layer away from the lamp surface of the display module corresponding to the gaps between different lamp beads, and forming the backlight layer includes:

Divide the position of the solder mask layer away from the lamp surface of the display module corresponding to the gaps between different lamp beads into a plurality of code bit regions, and print inks of different color levels at the positions corresponding to the different code bit regions , forming a backlight layer.

Further, dividing the position of the solder resist layer away from the lamp surface of the display module corresponding to the gaps of different lamp beads into a plurality of code bit areas includes:

Divide the side of the solder resist layer away from the lamp surface of the display module into a plurality of solder resist layer sub-regions with the location of each lamp bead as the center;

For each sub-region of the solder resist layer, the positions of the gaps corresponding to different lamp beads are divided into a plurality of the code bit regions.

Further, the ink of printing different color levels at the positions corresponding to different code bit regions includes:

The inks of different color levels are printed according to the preset color level range at the corresponding positions of different code bit areas.

The ink of the first preset color level is printed at the positions corresponding to the randomly selected preset number of different code bit regions, and the ink of the second preset color level is printed at the positions corresponding to the remaining code bit regions or is not processed.

It can be seen from the above description that the side of the solder resist layer away from the lamp surface of the display module is divided into a plurality of solder resist layer sub-regions with the position of each lamp bead as the center. The position corresponding to the gap between different lamp beads is divided into multiple code areas, and different color levels of ink are printed in different code areas, so that from the entire LED display, no obvious ink color deviation can be found from any angle. , which improves the ink color consistency of different modules, thereby improving the ink color consistency of the LED display screen.

Further, if the position corresponding to the remaining code bit area is printed with the ink of the second preset color level, the chromaticity difference between the first preset color level and the second preset color level is smaller than the first preset value.

As can be seen from the above description, since the chromaticity difference between the two color levels is smaller, that is, the gradient range between the two color levels is smaller, and the identity is higher, the preset color level is limited to two main color levels. , and the chromaticity difference between the two color levels is less than the preset difference, which can make the actual printing effect return to the two color levels, improve the consistency of the ink color of the screen, and improve the difference between the LED display. Ink consistency between batches of screens.

Further, printing ink on the side of the solder resist layer away from the lamp surface of the display module corresponding to the gaps between different lamp beads, and forming the backlight layer further includes the steps:

Determine the splicing area of different display modules;

dividing the splicing region into a plurality of splicing sub-regions;

Assign values to each splice subregion;

The corresponding ink printing is performed according to the assignment result of each spliced sub-area to form the backlight layer.

It can be seen from the above description that the splicing areas of different display modules are divided into a plurality of splicing sub-areas, each splicing sub-area is assigned a value, and then the corresponding ink printing is performed according to the assignment result of each splicing sub-area to form a backlight layer, It forms a layer of camouflage, which can weaken the gap in the splicing area of the display module, thereby weakening the boundary effect of the module, and further improving the consistency of the ink color of different display modules.

Further, the described assigning value to each splicing sub-area, and performing corresponding ink printing according to the assignment result of each splicing sub-area, forming the backlight layer includes:

Randomly assigning each splicing sub-region a second preset value or a third preset value;

For the splicing sub-region printing ink assigned as the second preset value, a backlight layer is formed;

The splicing sub-region assigned as the third preset value is not processed.

Further, the splicing area includes:

The splicing area is an area formed by extending a second preset distance from the splicing position of the display module to the direction of the lamp beads on both sides of the display module.

It can be seen from the above description that by randomly assigning each splicing sub-area to the second preset value or the third preset value, printing ink for the splicing sub-area assigned the second preset value to form a backlight layer, The splicing sub-areas of the three preset values are not processed, so that the splicing area is distributed with different color levels, thereby blurring the splicing area between different modules and weakening the modularity feature.

Further, the thickness of the backlight layer is greater than the thickness of the solder resist layer, and the thickness difference between the two is greater than a fourth preset value.

It can be seen from the above description that by increasing the thickness gap between the backlight layer and the solder mask layer, it is ensured that the transparency of the backlight layer is much lower than that of the solder mask layer, which reduces the transmittance, ensures a better backlight effect, and improves the ink display. The ability to use the thickness to cover up the volatilization problem of the ink during the printing process makes it easier to maintain the consistency of the ink color of the module.

Example 1

Please refer to Fig. 1-2, a method for printing ink color on an LED display screen of this embodiment includes the steps:

S1, printing ink on the lamp surface of the display module of the LED display screen at a position outside the area of the first preset distance from the pad 3' to form a solder resist layer 2';

For example, as shown in Figure 2, printing ink on the lamp surface of the display module of the LED display screen, only the edge position of the pad 3' is exposed to form a solder resist layer 2', and the solder resist layer 2' ink is extremely thin , to ensure the accuracy of the pad 3';

S2, printing ink on the side of the solder resist layer 2' away from the lamp surface of the display module corresponding to the gaps between different lamp beads 5' to form the backlight layer 1';

Wherein, the thickness of the backlight layer 1' is greater than the thickness of the solder resist layer 2', and the thickness difference between the two is greater than a fourth preset value;

Among them, in order to ensure that the visible position outside the range of the lamp bead is covered by the ink of the backlight layer after the lamp bead is welded, in addition to printing ink at the position corresponding to the gap between different lamp beads 5' to form the backlight layer, it is also under the position of the lamp bead. printing ink within the range of a preset distance from the gap to form a backlight layer;

For example, as shown in Fig. 2, printing ink in a certain range at the 4' position of the gap between the lamp bead and the lamp bead and the position of the lamp bead 5' to form the backlight layer 1' to ensure that the visible position outside the range of the lamp bead is covered by the backlight layer. Ink coverage; since the backlight layer 1' does not involve the precision of the pad, compared with the solder mask layer 2', the thickness of the backlight layer 1' is several times higher than that of the solder mask layer 2'. The performance of the thickness of different areas of layer 1' is less obvious than when the layer thickness is thin, and the amount of printing ink used in the backlight layer 1' is high, and the amount of volatilization per unit time is limited, and the limited amount of volatilization is not enough to make the printed The ink has obvious concentration difference, so it can improve the ink color consistency of the display module;

As a simple example, imagine there is a very thin piece of paper, through which you can see the shape of the pen behind it, and the difference between seeing the pen through one piece of paper and through two overlapping pieces of paper is more obvious. , but through 100 sheets of this paper and 150 sheets of this paper, the result is that the pen behind cannot be seen, so I use 100 layers of paper and 150 layers of paper. In contrast, the consistency of appearance is higher than that of one sheet and two sheets;

Among them, the solder mask ink and the backlight layer ink are the same ink, but they are different from each other, and the actual layer thickness difference is larger than the example. , the design is extremely thin, and the backlight layer 1' is more similar to the silk screen characters printed on the display module, and its thickness direction is visible to the naked eye, and the difference between the two is huge.

Embodiment 2

Please refer to FIGS. 3-7 and 9. Based on Embodiment 1, this embodiment further defines how to solve the problem of inconsistent ink colors between different display modules:

After thickening the backlight layer, if certain measures are not taken, the following situations will occur, that is, the backlight effect of a single display module is better, and the consistency of ink color is high, but it is seen between different display modules. , the consistency of the ink color will decrease, showing the ink color deviation of one piece and one piece, and between different LED displays, there will still be the problem of ink color deviation of different batches;

The reason for this problem is that when the layer thickness is increased, the deviation range of the highest point and the lowest point in the same layer of ink is also enlarged; the original deviation of 1 size unit to 2 size units can now be enlarged to From 10 size units to 20 size units, although there is no obvious difference in the thickness direction, they are all airtight black, but as long as the order of magnitude increases, there will still be deviations and inconsistencies;

As shown in Figure 3, the black level that can be distinguished by the naked eye is divided into 100 levels from low to high, and the order is not evenly divided. The higher the black, the smaller the gradient range, and the higher the identity; for an LED display module, to ensure the consistency of its ink color, its chromaticity range is preferably at the same level, the higher the level consistency, The higher the level average, the better the effect of maintaining the consistency of the ink color. However, through the solder mask process, the black level of the final display module is generally 20 to 25, and its left position is generally 20th order, and the position to the right is generally 25th order, which eventually leads to inconsistent ink color of the display module;

After the backlight layer printing process is applied to the display module, the position where the backlight layer is sprayed increases the chromaticity of the two uniformly, and both are raised by 30 steps. However, the left side is generally 50 steps, and the right side is generally 80 steps. Blackness, compared with 50-level and 80-level, the gradient range is smaller than 20-level and 25-level, the consistency of ink color is higher, and the blackness is darker, so the overall effect will be better than the original printing only one layer of solder mask , but there is still a chromaticity deviation from the 50th to the 80th stage. This deviation will also appear on the LED display after the number of display modules increases;

To solve the problem of inconsistent ink colors between different display modules, the core idea is to use the irregularity of pseudo-random sequences to generate a series of random and non-cyclic point sequences, and apply them to the segmented code bit regions;

Specifically, printing ink on the side of the solder resist layer away from the lamp surface of the display module corresponding to the gaps between different lamp beads, and forming the backlight layer includes:

Divide the position of the solder mask layer away from the lamp surface of the display module corresponding to the gaps between different lamp beads into a plurality of code bit regions, and print inks of different color levels at the positions corresponding to the different code bit regions , forming a backlight layer;

Wherein, dividing the position of the solder mask layer away from the lamp surface of the display module corresponding to the gaps between different lamp beads into a plurality of code bit areas includes:

For each sub-region of the solder mask layer, the positions of the gaps corresponding to different lamp beads are divided into a plurality of the code bit regions;

Among them, the code bit area can be randomly set, including any shape, such as rectangle or triangle, etc., and also includes any size. It can be divided according to the law of equal size, or it can be divided randomly according to different sizes, that is, digital camouflage technology. The process of random segmentation of the size is relatively difficult, but the effect is better;

For example, as shown in Figure 4-5, divide the side of the solder mask away from the lamp surface of the display module with the location of each lamp bead as the center, and divide it into 4 rectangular code bit areas of the same size, and encode them respectively. For 1, 2, 3, 4, or as shown in Figure 6-7, divide the side of the solder mask away from the lamp surface of the display module and take the position of each lamp bead as the center, and divide it into 20 squares of the same size Code bit area, which is coded according to 0 to 19 respectively;

Specifically, the inks for printing different color levels at positions corresponding to different code bit regions include:

Printing inks of different color levels according to the preset color level range at the corresponding positions of different code bit areas;

For example, by controlling the ink concentration, volatilization time, printing quality, etc., the color level of the ink is randomly toggled; originally, in order to maintain the consistency of the ink color, as shown in Figure 4-5, the color is printed in all four code positions. The ink with a gradation of 70, but in actual conditions, the final color gradation effect may be 50 gradations for the 1 and 2 code bits, and 80 gradations for the 3 and 4 code bits. There is an ink color deviation. This deviation is in It cannot be seen on the display module, but from the perspective of the LED display screen, obvious ink color deviation can be found at a specific angle, such as the lower right corner upwards; therefore, when printing ink, according to the preset color level range For printing, it is assumed that the color scale range is 40 to 90, that is, a random value within the color scale range is taken for each code point. The color level of the code point is 56 levels, and the color level of the 4-code point is 89 levels. Although from the perspective of a single lamp bead, the consistency of the ink color is reduced, but from the perspective of the entire screen, the consistency of the ink color is higher. No obvious ink color deviation will be found at any angle;

Among them, the process of controlling the ink color level of the backlight layer is not specifically limited, and the result is to control the level of the color level. The means include but are not limited to controlling different brush heads, ink concentration, processing environment, ink layer thickness, etc. Obviously, , as long as there are more code bit areas divided, the more densely divided the order of the color scale, the better the effect of the consistency of the ink color. , the corresponding processing technology requirements are higher;

The segmentation code area can be active segmentation or passive segmentation. Active segmentation controls the printing density, time, times, etc., while passive segmentation causes the actual ink color to fluctuate up and down a certain value through system errors;

The ink of the first preset color level is printed at the positions corresponding to the randomly selected preset number of different code bit regions, and the ink of the second preset color level is printed at the positions corresponding to the remaining code bit regions or is not processed;

Wherein, if the position corresponding to the remaining code bit area is printed with the ink of the second preset color level, the chromaticity difference between the first preset color level and the second preset color level is smaller than the first preset value;

For example, as shown in Figure 6-7, 8 code-bit areas are randomly selected, and the ink with a color level of 80 is printed in these 8 code-bit areas, and the ink with a color level of 50 is printed in the remaining 12 code-bit areas. There are only two kinds of color scales, and in actual conditions, the final color scale effect is the regression of these two color scales, that is, the actual color scale of the code position area where the printing ink color scale is 80 regresses around the 80 scale color scale, and the distribution Between 79, 78, 81, and 82, the actual color level of the code point area with the printing ink color level of 50 regresses around the 50-level color level, and is distributed between 49, 48, 51, and 52. With the divided code point area The more it is, the lower its technological requirements are, and it can also achieve the effect of ink color consistency;

Among them, the numbers in Figure 4-7 refer to the code bits, that is, the placement position of the code, not the code itself. According to different schemes, the code itself can be a pseudo-random sequence with alternating 1/0, or a black level. mark digits;

The pseudo-random sequence has only two results, 0 and 1, which is a finite number of random cycles between the two results of 0 and 1. Therefore, the discrimination method of the pseudo-random sequence is applied, and the two selection results are compared with the 0 and 1 of the pseudo-random sequence. Correspondingly, selecting one of the two results can achieve a limited range of randomness, continuously generating pseudo-random sequences during ink jetting, and performing corresponding operations according to different pseudo-random sequences when ink jetting for each code bit;

For example, as shown in Figure 9, assign a value to the divided code bit area, and assign the value to 1 or 0, and print ink with a high black level to the code bit area that is assigned a value of 1. Assuming that the ink with a color level of 80 is printed, For the code position with a value of 0 to print ink with a low black level, assuming that the ink with a printing color level of 50 is printed, the corresponding processing technology is to print ink of different concentrations or different amounts of ink in the code position area. The effect will not be stable at the set color level, but there is a toggle up and down based on the set color level. This toggle itself has the effect of weakening the difference, plus the code based on the pseudo-random number division. If the ink color deviation is smaller and the ink color gradation is more dense and uniform, the ink color consistency of the LED display screen is better, but the process requirements are also higher;

Or, for the code position printing ink assigned a value of 1, assuming that the printing color level is 80 ink, no ink is printed for the code position assigned a value of 0, and the original solder resist layer is retained, and the corresponding processing technology is in the code position area. It is easier to realize the difference between printing ink and not, and the cost is not high, but from the actual effect, a series of random non-circulating point sequence ensures the uniform distribution of the code positions printed on the backlight layer ink in the display module. , it may be that for some single lamp beads, the extreme phenomenon that the code bits corresponding to the lamp bead are all printed with ink or not printed with ink, but because the entire arrangement process is random and non-circulating, the order of magnitude of the lamp beads The larger the value, the better the ink color consistency of the display module, and the better the effect of the ink color consistency of the LED display;

Among them, no matter how much the black level is, it is a metaphor from several to dozens, and it is an example for the convenience of illustrating the ideological core of this scheme design;

From the perspective of practical application, it is extremely difficult to control the black level, and the current process requirements and methods are difficult to achieve. Therefore, it is more feasible to limit two main color levels and perform binary printing, which is about to be divided into two parts. 1 or 0, 1 and 0 respectively correspond to a color level, or 1 and 0 respectively correspond to the ink with or without the printed backlight layer, which are more feasible implementation processes.

Embodiment 3

Referring to FIG. 8 , this embodiment further defines how to eliminate the modular problem of the edge of the display module on the basis of the first embodiment or the second embodiment:

The step of printing ink on the side of the solder resist layer away from the lamp surface of the display module corresponding to the gaps between different lamp beads, forming the backlight layer further includes the steps:

Determine the splicing area of different display modules;

dividing the splicing region into a plurality of splicing sub-regions;

Assign values to each splice subregion;

Perform corresponding ink printing according to the assignment result of each splicing sub-region to form the backlight layer;

Wherein, assigning an assignment to each splicing sub-area, and performing corresponding ink printing according to the assignment result of each splicing sub-area, forming the backlight layer includes:

Do not process the splicing sub-region assigned as the third preset value;

Specifically, the splicing area includes:

The splicing area is an area formed by extending a second preset distance from the splicing position 7' of the display module to the direction of the lamp beads on both sides thereof;

Among them, the color level of the ink is close to the gap between the lamp bead and the lamp bead and the color level of the ink printed in a certain range under the lamp bead position. The size of the splicing sub-area is similar to the width of the splicing area of the two display modules. The width of the group splicing area is 0.1mm, then the size of the splicing sub-area is 0.01m ² ;

For example, the area formed by extending the pre-set distance from the stitching position 7' of the display module to the direction of the lamp beads on both sides is evenly divided into stitching sub-areas of the same size, assigning 1 or 0 to each stitching sub-area, and assigning a value of 1 or 0 to each stitching sub-area. The splicing sub-region with a value of 1 prints ink, and the splicing sub-region with a value of 0 does not print ink;

As shown in Figure 8, it shows part of the situation when two adjacent display modules A6' and B8' are spliced together. In the small-pitch display module, the size of the lamp bead is very small, and the position around the lamp bead is very small. The small square is the divided grid. The size of the grid is the same as the size of the display module's seam position 7'. This grid is an idealized model. In actual situations, the left and right sides of the seam are not uniform. , there may also be crooked lights and other phenomena between the lamp beads;

Among them, there are the following three ways to eliminate the gelatinization of the seam position:

The first is to extend a certain distance from the seam position of the display module to the direction of the lamp beads on both sides to form a circle of edge sealing, divide the edge sealing circle into grids of the same size, assign 1 or 0 to each grid, and assign the value of 0 to each grid. The grid with a value of 1 prints ink, and the grid with a value of 0 does not print ink, so as to ensure that the seam between the two display modules can be weakened to a certain extent, and at the same time, a large range of secondary printing ink is not required;

The second is to extend from the seam position of the display module to the direction of the lamp beads on both sides to the center of the display module, divide it evenly into grids of the same size, assign 1 or 0 to each grid, and assign a value of 1 to the grid. Grid printing ink, no ink is printed for the grid with the value of 0, the color level of the ink gradually changes from the center of the display module to the seam position of the display module, or from the seam position of the display module to the center of the display module. When dividing the area, the printing ink colors of the code bits in the corresponding area are arranged in the order of pseudo-random numbers, and the distribution is uniformly distributed on the whole. In addition, the black level is progressively advanced according to the level, and gradually approaches the display module seam. The color gradation of the position generally refers to the simple trend of the color gradation. In actual operation, this color gradation difference is not obvious relative to the solder mask itself;

Among them, the gradient level may lead to a black peak with the highest color level in the middle of the display module, and the color level of the black peak decreases cyclically around the circle. From the perspective of the screen, it appears as black poles. In fact, the poles are not It is not obvious, but it does affect the consistency of the ink color of the screen. You can divide a circular range in the middle of the display module to deal with the black front color level separately, and weaken the modularization problem caused by the high color level in the middle;

The third is to scramble and reorganize all the color blocks of the display module according to the level and edge seam, and also follow the pseudo-random number order to make the three color levels on the display module, including the seam level, the solder mask level The color gradation and the ink gradation of the character layer are all mixed together, using the difference in the degree, shape and texture of the three gradation blacks, according to the logic of random arrangement to present a uniform gradation distribution effect, that is, using the systematic error to improve the ink color Consistency, the effect of splicing different display modules is the best, and the cost is also the highest; the above three methods all use the superposition of ink on both sides to gelatinize and eliminate seams, thereby eliminating the modular problem of the edge of the display module. It can be classified as uniform superposition and superimposed according to specific rules. Through the random and non-circulating printing arrangement of grids of different color levels on both sides of the seam, the gap condition of the display module seam position is weakened. It is like printing a layer of camouflage on the patchwork, so as to improve the situation of the border patchwork of the module and weaken the modular effect of the module.

To sum up, the present invention provides an ink color printing method for an LED display screen. By printing two layers of ink on the LED display screen module, a solder mask layer and a backlight layer are formed. The thickness of the backlight layer is several times that of the solder mask layer. The thickness of the layer ensures that the transparency of the backlight layer is much lower than that of the solder mask layer, which reduces the transmittance, ensures a better backlight effect, and improves the display ability of ink colors. The positions corresponding to the gaps between different lamp beads on the side are divided into multiple code bit areas, and different color levels of ink are printed at the corresponding positions of different code bit areas to form a backlight layer, which solves the modularization problem of the display module and makes it From the perspective of the entire LED display, no obvious ink color deviation can be found from any angle, which improves the ink color consistency of the display module. In addition, the splicing area of different display modules is divided into multiple splicing sub-areas. The splicing sub-areas are assigned, and then the corresponding ink printing is performed according to the assignment result of each splicing sub-area to form a backlight layer, which forms a layer of camouflage and distributes different color levels, which can display the gap in the splicing area of the module. Weakening, thereby weakening the boundary effect of the module, further improving the ink color consistency of the screen, and improving the quality of the LED display.

The above descriptions are only examples of the present invention, and are not intended to limit the scope of the present invention. Any equivalent transformations made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in related technical fields, are similarly included in the within the scope of patent protection of the present invention.

Claims

An ink color printing method for an LED display screen, comprising the steps of:

Printing ink on the lamp surface of the display module of the LED display screen outside the area of the first preset distance from the pad to form a solder mask;

Ink is printed on the side of the solder resist layer away from the lamp surface of the display module at a position corresponding to the gap between different lamp beads to form a backlight layer.
The ink color printing method for an LED display screen according to claim 1, wherein the ink is printed on the side of the solder resist layer away from the lamp surface of the display module at a position corresponding to the gap between different lamp beads to form a backlight Layers include:

Divide the position of the solder mask layer away from the lamp surface of the display module corresponding to the gaps between different lamp beads into a plurality of code bit regions, and print inks of different color levels at the positions corresponding to the different code bit regions , forming a backlight layer.
The ink color printing method for an LED display screen according to claim 2 , wherein the positions of the solder resist layer on the side away from the lamp surface of the display module corresponding to the gaps between different lamp beads are divided into a plurality of codes The bit area includes:

Divide the side of the solder resist layer away from the lamp surface of the display module into a plurality of solder resist layer sub-regions with the location of each lamp bead as the center;

For each sub-region of the solder resist layer, the positions of the gaps corresponding to different lamp beads are divided into a plurality of the code bit regions.
The ink color printing method for an LED display screen according to claim 2 or 3, wherein the printing of inks of different color levels at positions corresponding to different code bit regions comprises:

The inks of different color levels are printed according to the preset color level range at the corresponding positions of different code bit regions.
The ink color printing method for an LED display screen according to claim 2 or 3, wherein the printing of inks of different color levels at positions corresponding to different code bit regions comprises:

The ink of the first preset color level is printed at the positions corresponding to the randomly selected preset number of different code bit regions, and the ink of the second preset color level is printed at the positions corresponding to the remaining code bit regions or is not processed.
The ink color printing method of the LED display screen according to claim 5, wherein, if the ink of the second preset color level is printed at the position corresponding to the remaining code position area, the first preset color level and the second preset color The chromaticity difference value of the level is smaller than the first preset value.
The ink color printing method for an LED display screen according to any one of claims 1 to 3, wherein the solder resist layer on the side of the solder resist layer away from the lamp surface of the display module corresponds to the gaps between different lamp beads. The position printing ink to form the backlight layer also includes the steps:

Determine the splicing area of different display modules;

dividing the splicing region into a plurality of splicing sub-regions;

Assign values to each spliced subregion;

The corresponding ink printing is performed according to the assignment result of each spliced sub-area to form the backlight layer.
The ink color printing method for an LED display screen according to claim 7, wherein the assigning a value to each splicing sub-area, performing corresponding ink printing according to the assignment result of each splicing sub-area, and forming the backlight layer comprises:

Randomly assigning each splicing sub-region a second preset value or a third preset value;

For printing ink in the splicing sub-region assigned as the second preset value, a backlight layer is formed;

The splicing sub-region assigned as the third preset value is not processed.
The ink color printing method for an LED display screen according to claim 8, wherein the splicing area comprises:

The splicing area is an area formed by extending a second preset distance from the splicing position of the display module to the direction of the lamp beads on both sides of the display module.
The ink color printing method for an LED display screen according to any one of claims 1 to 3, 6, 8, and 9, wherein the thickness of the backlight layer is greater than the thickness of the solder resist layer, and the thickness difference between the two is greater than the fourth preset value.
A display module, comprising:

The solder resist layer is located outside the area of the lamp surface of the display module that is the first preset distance from the pad;

The backlight layer is located on the side of the solder resist layer away from the lamp surface of the display module, and at least corresponds to the gap between the lamp beads, and the thickness of the backlight layer is greater than that of the solder resist layer.
The display module according to claim 11, wherein the solder resist layer and the backlight layer are formed by printing ink.
The display module according to claim 11, wherein the backlight layer comprises a plurality of code bit regions, and the backlight layer has inks of different color levels in different code bit regions.
The display module according to claim 11, wherein the backlight layer extends to a range of a second predetermined distance from the gap below the position of the lamp bead.