Highly efficient OLED pixel layer printing method, apparatus and storage medium

Abstract

The present invention relates to a highly efficient OLED pixel layer printing method, which includes the steps of: measuring the volume and speed of ink droplets ejected for each jet orifice in a pre-positioning driving waveform; closing the jet orifice corresponding to the ink droplet whose volume deviates by more than a standard volume pre-positioning percentage; calculating the effective deposition range of the ink droplets in the pixel microgroove; calculating the printing frequency of the inkjet print head and the moving speed of the printed circuit board; calculating the number of printings; determining the jet orifice to be driven for each printing and the number of ink droplets ejected from the jet orifice based on the number of jet orifices covering the effective deposition range, the number of ink droplets ejected from one jet orifice, and the volume of the ink droplets; driving the selected jet orifice to eject ink and deposit ink droplets in the pixel microgroove; determining whether the printing needs to continue; if not, terminating the printing; if necessary, moving the inkjet print head in the x direction or moving the printed circuit board in the y direction; driving the corresponding jet orifice to eject ink until the printing ends, and performing the next printing. Compared with the existing technology, the present invention has the advantage of high printing efficiency.

Description

[Technical Field]

[0001] The present invention relates to the field of OLED inkjet printing technology, and more particularly to a highly efficient OLED pixel layer printing method, apparatus and storage medium. [Background technology]

[0002] To ensure the display effect of the device, OLED pixel layer printing requires precise ink droplet volume and ink distribution deposited in the pixel microgrooves. Due to head manufacturing errors, each jet orifice will have a certain variation in the volume of droplets ejected with the same driving waveform. To ensure the same volume of ink droplets in each pixel microgroove, a method of using different driving waveforms for each jet orifice is usually adopted to keep the volume of ink droplets ejected from each jet orifice within a certain range. Furthermore, ejecting ink droplets using different jet orifices for each pixel microgroove ensures the stability of the total volume of ink droplets deposited in the pixel microgroove.

[0003] High-resolution printheads have thousands of jet orifices per printhead, and controlling the drive waveform for each jet orifice independently makes the control system extremely complex. Furthermore, satisfying the total volume of ink droplets within a pixel microgroove by ejecting ink droplets from different jet orifices leads to problems such as reduced printing efficiency, complex jet orifice combination algorithms, and uneven ink droplet drying performance at different times. Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE INVENTION In order to overcome the drawbacks of the prior art, the present invention aims to provide a highly efficient OLED pixel layer printing method, apparatus and storage medium, thereby improving printing efficiency. [Means for solving the problem]

[0005] The object of the present invention can be achieved by the following technical solutions.

[0006] A highly efficient OLED pixel layer printing method includes the following steps: The volume and velocity of ink droplets ejected from each jet orifice in the pre-positioning drive waveform are measured, and jet orifices corresponding to ink droplets whose volumes deviate by more than a standard volume pre-positioning percentage are closed; Calculating the effective deposition range of the ink droplets in the pixel microgrooves from the volume, velocity, deposition position, deposition time interval of the ink droplets, and the wettability and geometric structure of the pixel microgrooves; Calculate the print frequency of the inkjet print head and the movement speed of the printed circuit board from the production takt time and ink viscosity. The number of prints is calculated based on the geometric structure of the pixel microgroove, the inkjet condition of the jet orifice, the print frequency of the inkjet printhead, and the movement speed of the printed circuit board. determining which jet orifices to drive and the number of ink droplets to be ejected from each jet orifice for each printing operation based on the number of jet orifices covered by the effective deposition range, the number of ink droplets to be ejected from each jet orifice, and the volume of the ink droplets; actuating selected jet orifices to eject ink and deposit ink droplets into pixel microgrooves; It determines whether printing needs to continue, and if not, terminates the printing. If necessary, it moves the inkjet print head in the x direction or moves the printed circuit board in the y direction, and drives the corresponding jet orifice to eject ink until the printing is completed, and then performs the next printing.

[0007] The preposition percentage is ±5%.

[0008] The ink jet conditions of the jet orifice include the volume of ink droplets ejected from the jet orifice and the operating state of the jet orifice.

[0009] The operating conditions of the jet orifice include normal, scattering spray, and oblique spray. A normal operating condition of the jet orifice refers to droplets that are uniform in size and have a stable volume ejected from the jet orifice, with a vertical drop point accuracy error of ±5 μm / 1 mm (1 mm is the distance between the jet orifice and the substrate). A scattering spray operating condition of the jet orifice refers to droplets that are ejected from the jet orifice with uneven size and divergence in all directions, which is mainly caused by multiple factors such as corrosion around the jet orifice, unstable waveform pressure, and a mismatch between the droplet tension, viscosity, and melting properties of the jet orifice surface. A oblique spray operating condition of the jet orifice refers to droplets that are ejected from the jet orifice with a stable volume ejected onto the substrate at a certain inclination angle, with a drop point error typically exceeding ±5 μm / 1 mm, which is mainly caused by corrosion on the jet orifice surface.

[0010] The distance of one movement of the inkjet print head in the x direction or the printed circuit board in the y direction is an integer multiple of the pitch of adjacent jet orifices.

[0011] The number of ink droplets ejected from the jet orifice is determined by the print frequency of the ink jet printhead and the speed of movement of the printed circuit board.

[0012] The number of ink droplets ejected from the jet orifice is proportional to the printing frequency of the ink jet printhead and inversely proportional to the speed of movement of the printed circuit board.

[0013] A highly efficient OLED pixel layer printing device includes a host computer, a print controller, a motion controller, an inkjet printhead, and a printed circuit board, wherein the host computer sends control information to control the print controller and the motion controller in the above-mentioned manner, the print controller controls the inkjets of the inkjet printhead according to the control information, and the motion controller controls the movements of the inkjet printhead and the printed circuit board based on the control information.

[0014] The print controller controls the inkjets of the inkjet printhead, including selecting and activating jet orifices to eject ink droplets of desired volume, velocity, and ejection angle from the jet orifices.

[0015] A storage medium on which a program is stored, and when the program is executed, the above-mentioned method is realized. [Effects of the Invention]

[0016] The present invention has the following advantages over the prior art.

[0017] (1) The present invention uses the same driving waveform for all jet orifices in the head, simplifying the control system and reducing the complexity of the control.

[0018] (2) The present invention first defines the effective deposition range based on the ink characteristics, substrate characteristics, and printing conditions. If the ink droplets ejected from a certain jet orifice are within the effective deposition range, the high-frequency ejection characteristics of the head can be used to continuously eject multiple droplets from the same jet orifice into a certain pixel microgroove during the printing process, thereby reducing the variation in the drying performance of ink droplets ejected at different times.

[0019] (3) In the printing method of the present invention, by simply increasing the number of jet orifices covering the effective deposition area, moving the inkjet print head, increasing the jetting frequency of the inkjet print head, or slowing down the movement speed of the printed circuit board, the selection range of ink droplets deposited in one pixel microgroove can be increased, the number of printing times can be reduced, and the printing efficiency can be improved, making it simple and efficient. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a flow chart of the method of the present invention. [Figure 2] FIG. 1 is a schematic diagram of an OLED pixel layer inkjet printing apparatus. [Figure 3] FIG. 1 is a schematic diagram of the OLED pixel layer inkjet forming process. [Figure 4] FIG. 1 is a schematic diagram of the final formed pixel layer of an OLED pixel layer inkjet. [Figure 5] FIG. 1 is a schematic diagram of OLED pixel layer inkjet printing error accumulation. [Figure 6] 1 is a schematic diagram of a method for eliminating volume errors of ink droplets deposited in pixel microgrooves. FIG. [Figure 7] FIG. 5 is a schematic diagram illustrating the printing process of the method of FIG. 4. [Figure 8] FIG. 10 illustrates a combination of complementary jet orifices with different jet orifice pitches. [Figure 9] FIG. 1 is a schematic diagram of the effective deposition area within pixel microgrooves. [Figure 10] FIG. 1 is a schematic diagram of a method for printing a highly efficient OLED pixel layer. [Figure 11] FIG. 10 is a schematic diagram showing how the effective deposition area of ​​the long side of one pixel microgroove covers the number of jet orifices. DETAILED DESCRIPTION OF THE INVENTION

[0021] The present invention will be described in detail below with reference to the drawings and specific examples. The examples show detailed embodiments and specific operating procedures implemented based on the claims of the present invention, but the scope of the present invention is limited to the following examples.

[0022] As shown in Figure 2, the OLED pixel layer inkjet printing device , Ho Store Computer 110, P Lint Controller 120, Mo Application Controller 130, I inkjet printhead 140 and pu Lint board 170 The host computer controls the print controller and motion controller and is responsible for sending commands throughout the inkjet printing process. 2 The motion controller 130 controls the inkjet printhead 140, including selecting and activating the jet orifices 150 to eject ink droplets 160 from the jet orifices 150 with the desired volume, velocity, and ejection angle. 4 0 and the movement of the printed circuit board 170, the ink droplets 160 to be ejected Print The deposition is effected within pixel microgrooves 180 on the substrate 170 .

[0023] The inkjet molding process for the OLED pixel layer, as shown in Figure 3, involves depositing multiple ink droplets 1601, 1602, 1603, 1604, etc., at a constant speed and volume within pixel microgrooves 1801, 1802, 1803 of a printed circuit board 170. The number of ink droplets within the pixel microgrooves can be multiple, depending on factors such as the total volume of liquid deposited within the pixel microgroove and the volume of each ink droplet. As shown in Figure 4, the ink droplets 1601, 1602, 1603, 1604, etc. collide with pixel microgrooves 1801, 1802, 1803, etc. at a constant speed, fuse, and finally evaporate to form pixel layers 2601, 2602, 2603 within the pixel microgrooves.

[0024] Due to manufacturing tolerances for jet orifices, the volume error of ink droplets ejected from different jet orifices using the same drive waveform is within ±5%. As shown in Figure 5, assuming that 40 pL of ink needs to be deposited in each pixel microgroove, the volume of ink droplets ejected from each jet orifice is 10±0.5 pL. If the volume of ink droplets ejected from jet orifice 1501 is 10.5 pL and pixel microgroove 1801 is completely filled with ink droplets ejected from jet orifice 1501, the total volume of ink droplets deposited in pixel microgroove 1801 is 42 pL. If the volume of ink droplets ejected from jet orifice 1502 is 9.5 pL and pixel microgroove 1802 is completely filled with ink droplets ejected from jet orifice 1502, the total volume of ink droplets deposited in pixel microgroove 1802 is 38 pL. The total volume of ink droplets deposited in pixel microgrooves 1801 and 1802 deviates from the required value of 40 pL by 5%, but the total volume of ink droplets deposited between pixel microgroove 1801 and pixel microgroove 1802 differs by 10%, which far exceeds the performance requirements of the OLED device.

[0025] One method for reducing the total volume error of ink droplets within pixel microgrooves is to deposit ink droplets ejected from different jet orifices within a pixel microgroove. As shown in Figure 6, if the volume of ink droplets ejected from jet orifice 1501 is 10.5 pL and the volume of ink droplets ejected from jet orifice 1502 is 9.5 pL, pixel microgrooves 1801 and 1802 each eject two ink droplets from jet orifice 1501 and jet orifice 1502, respectively. Therefore, the total volume of ink droplets deposited within pixel microgrooves 1801 and 1802 is 40 pL. However, in actual inkjet printing processes, it is difficult to simultaneously find jet orifice combinations with complementary ink droplet volumes for multiple pairs of ink droplets. Therefore, during a single printing run, many jet orifices may be left empty due to a lack of complementary jet orifice combinations, reducing the overall efficiency of inkjet printing. Furthermore, this method increases the number of prints and reduces printing efficiency. 7 , the jet orifices 1510 and 1520 are a complementary jet orifice pair, and during the first print, ink droplets ejected from the jet orifices 1510 and 1520 fall into the pixel microgrooves 1810 and 1820, respectively. During the second print, the inkjet print head 140 moves a distance so that the jet orifice 1520 aligns with the pixel microgroove 1810, and then the jet orifice 1520 deposits ink droplets into the pixel microgroove 1810. During the third print, the inkjet print head 140 moves again so that the jet orifice 1510 aligns with the pixel microgroove 1820, and then the jet orifice 1510 deposits ink droplets into the pixel microgroove 1820. This shows that for a pair of jet orifices with complementary ink drop volumes, if one jet orifice deposits two ink drops into the corresponding pixel microgroove, three prints are required to complete the printing corresponding to the two pixel microgrooves.8 , when the pitches of the two jet orifices in the complementary jet orifice combinations 2510, 2520, and 2530 are different, the inkjet print head 140 may need to move up to six times to complete printing of the pixels corresponding to these three jet orifice combinations, and each of the jet orifices in these three jet orifice combinations is aligned with the pixel microgroove once. Therefore, as the number of jet orifice combinations increases, the number of printing times increases rapidly, and the printing efficiency decreases significantly.

[0026] The present invention proposes a highly efficient method for printing OLED pixel layers, as shown in FIG.

[0027] In one embodiment, a method for printing a highly efficient OLED pixel layer includes the following steps.

[0028] The volume and velocity of ink droplets ejected from each jet orifice of an inkjet print head using a set driving waveform are measured, and the jet orifice corresponding to ink droplets whose volume deviates from the standard volume by 5% or more is closed.

[0029] The effective deposition area of ​​the ink droplet in the pixel microgroove is calculated from the ink droplet volume, velocity, deposition position, deposition time interval, and the wettability and geometric structure of the pixel microgroove. As shown in Figure 9, the effective deposition areas of pixel microgrooves 1830 and 1840 are 1830' and 1840', respectively.

[0030] The print frequency of the inkjet print head and the movement speed of the printed circuit board are calculated from the production takt time and ink viscosity.

[0031] The printing number is calculated based on the geometric structure of the pixel microgroove, the volume of the ink droplets ejected from the jet orifice, the operating state of the jet orifice, the printing frequency of the inkjet printhead, and the moving speed of the printed circuit board, and the operating state of the jet orifice includes normal, scattering spray, and oblique spray.

[0032] Based on the number of jet orifices covered by the effective deposition range, the number of ink droplets ejected from one jet orifice, and the volume of the ink droplets, the jet orifices to be driven and the number of ink droplets to be ejected from the jet orifices are confirmed for each printing.

[0033] 8, the arrangement direction of the jet orifices is the x-direction, and the movement direction of the substrate is the y-direction. The substrate orientation is adjusted so that the long side of pixel microgroove 1830 is aligned with the x-direction. At a certain position, jet orifices 1501, 1502, 1503, and 1504 of inkjet print head 140 cover an effective deposition area 1830' corresponding to pixel microgroove 1830, and the number of jet orifices covered by the effective deposition area is four.

[0034] 10, at a certain ejection frequency and movement speed, one jet orifice can eject three ink droplets into the pixel microgroove 1830 during the printing process, that is, the number of ink droplets ejected from one jet orifice is three.

[0035] If 40 pL of ink needs to be deposited in each pixel microgroove, the volume of the ink droplets ejected from each jet orifice is in the range of 10±0.5 pL, and in one printing process, four droplets are selected from 12 ink droplets, such as 1601-1, 1601-2, ..., 1604-3, to meet the volume requirement of ink deposited in each pixel microgroove.

[0036] Inkjet printhead 140 By utilizing the high frequency ink jet characteristics of the ink jet head, selected jet orifices 1501, 1502, 1503, 1504 are driven to eject ink as they pass through the print area of ​​the effective deposition range 1830', depositing four selected ink droplets into the pixel microgroove 1830.

[0037] It is determined whether printing needs to be continued, and if not, the printing is terminated. If necessary, the inkjet print head is moved in the x direction by a distance that is an integer multiple of the adjacent jet orifice pitch, or the printed circuit board is moved in the y direction by a distance that is an integer multiple of the adjacent jet orifice pitch, and the corresponding jet orifice is driven to eject ink until the printing is completed, and the next printing is performed.

[0038] As shown in Figure 11, in this embodiment, the inkjet print head is moved to perform repeated printing. By moving the inkjet print head 140 in the x direction and performing repeated printing, One The number m of jet orifices covered by the effective deposition area of ​​the long side of the pixel microgroove can be doubled. During the first printing, jet orifices 1501, 1502, 1503, and 1504 of the inkjet print head 140 cover the effective deposition area 1830' corresponding to the pixel microgroove 1830. After the first printing is completed, the jet orifices are moved by an integer multiple of the pitch of the adjacent jet orifices in the x direction so that jet orifices 1511, 1512, 1513, and 1514 cover the effective deposition area 1830', and then the second printing is performed.

[0039] Assuming that the effective deposition area of ​​the long side of each pixel microgroove covers m jet orifices, if n ink droplets can be ejected from one jet orifice when the width direction of each pixel microgroove passes through the printing area during the printing process, then m*n ink droplets can be selected for each pixel microgroove to meet the deposited ink volume requirement. Furthermore, if the effective deposition area of ​​the long side of each pixel microgroove covers m jet orifices, the number of ink droplets that one jet orifice can eject when the width direction of each pixel microgroove passes through the printing area during the printing process can be further improved in a certain way. During the entire printing process, if the inkjet print head is moved once in the x direction (i.e., two printing times), the number of jet orifices that the effective deposition area of ​​the long side of each pixel microgroove covers increases from m to 2m. If the inkjet print head is moved once again in the x direction (i.e., three printing times), m increases to 3m. Increasing the jetting frequency of the inkjet printhead or slowing the movement speed of the printed circuit board can increase the number of ink droplets (n) jetted from one jet orifice as each pixel microgroove passes through the print area during the printing process. For example, doubling the jetting frequency or halving the movement speed of the board can increase n to 2n. Combining the methods of increasing m and n significantly improves the selectivity of ink droplets deposited within each pixel microgroove, thereby improving printing efficiency.

[0040] When these functions are realized as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the claims of the present invention, in essence, or the portion that contributes to the prior art, or the portion of the claims of the present invention, can be embodied in the form of a software product stored in a storage medium, which includes instructions that enable a computer device (which may be a personal computer, a server, a network device, etc.) to execute all or part of the method steps described in various embodiments of the present invention. The storage medium includes various media that can store program code, such as a USB memory, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

Claims

1. 1. A method for printing a highly efficient OLED pixel layer, comprising: The volume and velocity of ink droplets ejected from each jet orifice in the pre-positioning drive waveform are measured, and jet orifices corresponding to ink droplets whose volumes deviate by more than a standard volume pre-positioning percentage are closed; Calculating the effective deposition range of the ink droplets in the pixel microgrooves from the volume, velocity, deposition position, deposition time interval of the ink droplets, and the wettability and geometric structure of the pixel microgrooves; Calculate the print frequency of the inkjet print head and the movement speed of the printed circuit board from the production takt time and ink viscosity. The number of prints is calculated based on the geometric structure of the pixel microgroove, the inkjet condition of the jet orifice, the print frequency of the inkjet printhead, and the movement speed of the printed circuit board. determining the jet orifices to be driven and the number of ink droplets to be ejected from the jet orifices for each printing operation based on the number of jet orifices covered by the effective deposition range, the number of ink droplets to be ejected from each jet orifice, and the volume of the ink droplets; actuating selected jet orifices to eject ink and deposit ink droplets into pixel microgrooves; The method includes the steps of: determining whether it is necessary to continue printing; if it is not necessary, terminating the printing; if necessary, moving the inkjet print head in the x direction or moving the printed circuit board in the y direction, and driving the corresponding jet orifice to eject ink until the printing is completed, thereby performing the next printing; In each printing, the number of jet orifices covered by the effective deposition range is plural, and the number of ink droplets that each jet orifice can eject is plural; The number of ink droplets ejected from the jet orifice is determined by the printing frequency of the inkjet printhead and the moving speed of the printed circuit board.

2. 10. The method of printing a highly efficient OLED pixel layer of claim 1, wherein the standard volume pre-deposition percentage is ±5%.

3. 2. The method for printing a highly efficient OLED pixel layer as claimed in claim 1, wherein the ink jet conditions of the jet orifice include the volume of ink droplets ejected from the jet orifice and the operating state of the jet orifice.

4. 4. The method for printing a highly efficient OLED pixel layer as claimed in claim 3, wherein the operating states of the jet orifice include normal, scattering spray and oblique spray.

5. 2. The method for printing a highly efficient OLED pixel layer according to claim 1, wherein a distance of one movement of the inkjet print head in the x-direction or the printed circuit board in the y-direction is an integer multiple of a pitch of adjacent jet orifices.

6. 2. The method for printing a highly efficient OLED pixel layer according to claim 1, wherein the number of ink droplets ejected from the jet orifice is proportional to the printing frequency of the inkjet printhead and inversely proportional to the moving speed of the printed circuit board.

7. 10. A highly efficient OLED pixel layer printing apparatus comprising: a host computer; a print controller; a motion controller; an inkjet printhead; and a printed circuit board, wherein the host computer sends control information according to the method of claim 1 to control the print controller and the motion controller, the print controller controls the inkjets of the inkjet printhead according to the control information, and the motion controller controls movement of the inkjet printhead and the printed circuit board based on the control information.

8. 8. The highly efficient OLED pixel layer printing apparatus of claim 7, wherein the print controller controls the inkjets of the inkjet printhead by selecting and driving jet orifices, and controlling the jet orifices to eject ink droplets with required volume, velocity, and ejection angle.

9. A storage medium having a program stored thereon, the storage medium implementing the method of claim 1 when the program is executed.

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