CN115107370A - Efficient OLED pixel layer printing method and device and storage medium - Google Patents

Abstract

The invention relates to a high-efficiency OLED pixel layer printing method, which comprises the following steps: measuring the volume and the speed of ink drops ejected by each jet orifice under the preconfigured driving waveform, and closing the jet orifices corresponding to the ink drops with the volume deviating from the standard volume by more than preconfigured percentage; calculating the effective deposition range of the ink drop in the pixel micro-groove; calculating the printing frequency of the ink-jet printing head and the movement speed of the printing substrate; calculating the printing times; determining the number of the jet holes driven by each printing and the number of ink drops jetted by the jet holes according to the number of the jet holes covered by the effective deposition range, the number of ink drops jetted by a single jet hole and the volume of ink drops; driving the selected jet orifice to jet ink, and depositing ink drops into the pixel micro-grooves; and judging whether the printing needs to be continued, if not, finishing the printing, if so, moving the ink jet printing head along the x direction or the printing substrate along the y direction, and driving the corresponding jet orifice to jet ink to perform the next printing until the printing is finished. Compared with the prior art, the invention has the advantages of high printing efficiency and the like.

Description

A high-efficiency OLED pixel layer printing method, device and storage medium

technical field

The present invention relates to the technical field of OLED inkjet printing, in particular to a high-efficiency OLED pixel layer printing method, device and storage medium.

Background technique

In order to ensure the display effect of the device, OLED pixel layer printing has precise requirements on the volume and distribution of ink droplets deposited in the pixel micro-grooves. Due to the manufacturing error of the nozzle, the volume of droplets ejected by each nozzle hole has a certain deviation under the same driving waveform. In order to ensure the same volume of ink droplets in each pixel micro-groove, a common method is to use different driving waveforms for different orifices, so that the volume of ink droplets ejected from each orifice is kept within a certain range. Further, for a single pixel micro-groove, different nozzle holes are used to eject ink droplets to ensure that the total volume of ink droplets deposited in the pixel micro-groove is stable.

For high-resolution nozzles, each nozzle has thousands of nozzle holes. If each nozzle hole independently controls the driving waveform, the control system is very complicated. In addition, using different orifices to eject ink droplets to meet the conservation of the total volume of ink droplets in the pixel micro-grooves will cause problems such as low printing efficiency, complex orifice combination algorithms, and inconsistent drying performance of ejected ink droplets at different times.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a high-efficiency OLED pixel layer printing method, device and storage medium in order to overcome the above-mentioned defects of the prior art, so as to improve the printing efficiency.

The object of the present invention can be realized through the following technical solutions:

A high-efficiency OLED pixel layer printing method, comprising the following steps:

Measure the volume and velocity of the ink droplets ejected from each orifice under the pre-configured driving waveform, and close the orifice corresponding to the ink drop whose volume deviates from the standard volume pre-configured percentage or more;

Calculate the effective deposition range of ink droplets in the pixel micro-grooves according to the volume, velocity, deposition position, deposition time interval, and the wettability and geometric structure of the pixel micro-grooves;

Calculate the printing frequency of the inkjet print head and the movement speed of the printing substrate according to the production tact and ink viscosity;

Calculate the number of prints according to the pixel micro-groove geometry, orifice inkjet situation, inkjet printhead printing frequency and printing substrate movement speed;

According to the number of orifices covered by the effective deposition range, the number of ink droplets ejected by a single orifice, and the volume of the ink droplets, determine the number of orifices driven and the number of ink droplets ejected by the orifices during each printing;

Drive the selected orifice to eject ink to deposit ink droplets into the pixel micro-grooves;

Determine whether it is necessary to continue printing, if no, end printing, if yes, move the inkjet print head in the x direction or move the printing substrate in the y direction, and drive the corresponding nozzles to ink jet for the next printing until the end of printing.

The preconfigured percentage is ±5%.

The jetting condition of the jetting hole includes the volume of ink droplets jetting out of the jetting hole and the working state of the jetting hole.

The working states of the spray holes include normal spray, scattered spray, and oblique spray. The normal working state of the nozzle means that the droplet ejects a complete and stable droplet from the nozzle hole, and the drop point accuracy error in the vertical direction is ±5μm/1mm (1mm refers to the distance between the nozzle hole and the substrate. distance); the said spray hole working state scattered spray means that the size of the droplets ejected from the spray hole is uneven and diverges everywhere, mainly due to the erosion of the edge of the spray hole, unstable waveform pressure, droplet tension and viscosity It is caused by a number of factors such as the mismatch with the surface of the orifice; the oblique spray in the working state of the orifice means that droplets with a stable volume are ejected from the orifice and sprayed onto the substrate at a certain oblique angle. The point error exceeds ±5μm/1mm, mainly due to the corrosion of the nozzle surface.

Each movement distance of moving the inkjet print head along the x-direction or moving the printing substrate along the y-direction is an integer multiple of the spacing between adjacent nozzle holes.

The number of ink droplets ejected by the nozzle holes is determined by the printing frequency of the inkjet print head and the movement speed of the printing substrate.

The number of ink droplets ejected by the nozzle holes is proportional to the printing frequency of the inkjet print head and inversely proportional to the moving speed of the printing substrate.

A high-efficiency OLED pixel layer printing device, comprising a main control computer, a printing controller, a motion controller, an inkjet print head, and a printing substrate, the main control computer sends control information to the printing controller and the printing controller according to the method described above. The motion controller performs control, the print controller controls the ink jetting of the ink jet print head according to the control information, and the motion controller controls the motion of the ink jet print head and the printing substrate according to the control information.

The printing controller controlling the ink jetting of the ink jet printing head includes: selecting and driving the jet holes, and controlling the jet holes to jet out ink droplets whose volume, speed and jet angle meet the requirements.

A storage medium on which a program is stored, and when the program is executed, the method as described above is implemented.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The present invention adopts the same driving waveform for all the nozzle holes of the nozzle, the control system is simple, and the control complexity is reduced.

(2) The present invention first defines an effective deposition range according to ink characteristics, substrate characteristics and printing conditions. If the jetted ink droplets corresponding to a certain nozzle are within the effective deposition range, the high-frequency jetting characteristics of the nozzle can be used to achieve the same effect during the printing process. The nozzle holes can continuously spray multiple droplets into a certain pixel micro-groove, which can alleviate the problem of inconsistent drying performance of the sprayed ink droplets at different times.

(3) Using the printing method of the present invention, as long as the effective deposition range is increased to cover the number of orifices, the inkjet printing head is moved, the injection frequency of the inkjet printing head is increased, or the movement speed of the printing substrate can be reduced, the micro-groove of a single pixel can be increased. The selection range of the deposited ink droplets reduces the number of printings, thereby improving the printing efficiency, which is simple and efficient.

Description of drawings

Fig. 1 is the method flow chart of the present invention;

2 is a schematic diagram of an OLED pixel layer inkjet printing device;

3 is a schematic diagram of an inkjet forming process of an OLED pixel layer;

FIG. 4 is a schematic diagram of the pixel layer finally formed by inkjet of the OLED pixel layer;

5 is a schematic diagram of accumulation of inkjet printing errors of an OLED pixel layer;

6 is a schematic diagram of a method for eliminating the volume error of deposited ink droplets in pixel micro-grooves;

7 is a schematic diagram of a printing process of the method of FIG. 4;

8 is a schematic diagram of a combination of complementary orifices with different orifice spacings;

9 is a schematic diagram of an effective deposition range in a pixel micro-groove;

10 is a schematic diagram of an efficient OLED pixel layer printing method;

FIG. 11 is a schematic diagram of a method for increasing the number of orifices covered by the effective deposition area of the long side of a single pixel micro-groove.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation manner and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

As shown in FIG. 2 , the OLED pixel layer inkjet printing apparatus includes 110 a main control computer, 120 a printing controller, 130 a motion controller, 140 an inkjet printing head and 170 a printing substrate. The main control computer controls the printing controller and the motion controller, and is responsible for sending the instructions of the entire inkjet printing process. The printing controller 130 controls the inkjet print head 140 , including selecting and driving the nozzle holes 150 , and controlling the nozzle holes 150 to eject ink droplets 160 with a volume, speed and ejection angle that meet the requirements. The motion controller 130 controls the motion of the inkjet print head 150 and the printing substrate 170 to deposit the ejected ink droplets 160 into the pixel micro-grooves 180 on the substrate 170 .

The inkjet forming process of the OLED pixel layer is shown in FIG. The number of ink droplets in the pixel micro-groove may be multiple, and the number of ink droplets is determined by factors such as the total volume of liquid deposited in the pixel micro-groove and the volume of a single ink droplet. The ink droplets 1601, 1602, 1603, 1604, etc. collide with the pixel micro-grooves 1801, 1802, 1803, etc. at a certain speed, and then merge, and finally evaporate to form pixel layers 2601, 2602, and 2603 in the pixel micro-grooves, as shown in Figure 4. Show.

Due to the manufacturing error of the orifice, under the same driving waveform, the volume error of the ink droplets ejected by different orifices is within ±5%. As shown in Figure 5, it is assumed that 40 pL of ink needs to be deposited in the micro-grooves of each pixel, and the volume of ink droplets ejected from each orifice is 10 ± 0.5 pL. If the volume of ink droplets ejected from the orifice 1501 is 10.5 pL, and the pixel micro-grooves 1801 are all filled with ink droplets ejected from the orifices 1501 , the total volume of ink droplets deposited in the pixel micro-grooves 1801 is 42 pL. If the volume of ink droplets ejected from the orifice 1502 is 9.5 pL, and the pixel micro-grooves 1802 are all filled with ink droplets ejected from the orifices 1502 , the total volume of ink droplets deposited in the pixel micro-grooves 1802 is 38 pL. The deviation of the total volume of the deposited ink droplets between the pixel micro-grooves 1801 and 1802 relative to the demand value of 40 pL is 5%, while the total volume of the deposited ink droplets between the pixel micro-groove 1801 and the pixel micro-groove 1802 differs by 10%, far exceeding performance requirements of OLED devices.

A method for reducing the total volume error of ink droplets in a pixel micro-groove is to use different nozzle holes to eject ink droplets and deposit them into a certain pixel micro-groove. As shown in FIG. 6 , it is assumed that the volume of ink droplets ejected from orifice 1501 is 10.5 pL, and the volume of ink droplets ejected from orifice 1502 is 9.5 pL. Ink droplets. Therefore, the total volume of the ink droplets deposited in the pixel micro-grooves 1801 and 1802 is both 40 pL. However, in the actual inkjet printing process, it is difficult to find multiple groups of orifice combinations with complementary volumes of ink droplets at one time. Therefore, during a single printing, a large number of orifices are idle due to the inability to find complementary orifice combinations, resulting in The overall efficiency of inkjet printing is reduced. In addition, using this method will also result in an increase in the number of prints, thereby reducing the print efficiency. As shown in FIG. 7 , the nozzle holes 1510 and 1520 are complementary nozzle groups. During the first printing, the ink droplets ejected by the nozzle holes 1510 and 1520 fall into the pixel micro-grooves 1810 and 1820 respectively; during the second printing , the inkjet print head 140 moves a certain distance so that the nozzle holes 1520 are aligned with the pixel micro-grooves 1810, and then the nozzle holes 1520 deposit ink droplets into the pixel micro-grooves 1810; during the third printing, the ink-jet print head 140 moves again to make The orifices 1510 are aligned with the pixel micro-grooves 1820 and then the orifices 1510 deposit ink droplets into the pixel micro-grooves 1820 . It can be seen that for each group of orifice combinations with complementary ink droplet volumes, in the case where each orifice deposits 2 ink droplets into the corresponding pixel micro-grooves, it takes three times of printing to complete the printing of the corresponding 2 pixel micro-grooves . As shown in FIG. 8 , when the spacing between the two orifices corresponding to the complementary orifice combinations 2510 , 2520 and 2530 is different, to complete the printing of the pixels corresponding to the three groups of orifice combinations, the inkjet print head 140 may need to move at most 6 times. Align each orifice of the three groups of orifice combinations with the pixel micro-grooves once, respectively. Therefore, as the number of orifice combinations increases, the number of prints will increase rapidly, thereby greatly reducing the printing efficiency.

The present invention proposes a high-efficiency OLED pixel layer printing method, as shown in FIG. 1 .

In one embodiment, a high-efficiency OLED pixel layer printing method includes the following steps:

Measure the volume and velocity of ink droplets ejected from each nozzle hole in the inkjet print head under a certain set driving waveform, and close the nozzle holes corresponding to the ink droplets whose volume deviates by more than 5% from the standard volume.

The effective deposition range of ink droplets in the pixel micro-grooves is calculated according to the volume, velocity, deposition position, deposition time interval, and the wettability and geometric structure of the pixel micro-grooves. As shown in FIG. 9, the effective deposition ranges of the pixel micro-grooves 1830 and 1840 are 1830' and 1840', respectively.

Calculate the printing frequency of the inkjet print head and the movement speed of the printing substrate according to the production tact and ink viscosity.

The number of times of printing is calculated according to the geometric structure of the pixel micro-groove, the volume of ink droplets ejected from the orifice, the working state of the orifice, the printing frequency of the inkjet print head and the movement speed of the printing substrate, wherein the working state of the orifice includes normal, scattered, inclined spray.

According to the number of nozzle holes covered by the effective deposition range, the number of ink droplets ejected by a single nozzle hole and the volume of the ink droplets, the nozzle holes driven and the number of ink droplets ejected by the nozzle holes are determined in each printing.

As shown in FIG. 8 , the arrangement direction of the nozzle holes is set as the x direction, and the movement direction of the substrate is set as the y direction, and the direction of the substrate is adjusted so that the direction of the long sides of the pixel micro-grooves 1830 is aligned with the x direction. At a certain position, the orifices 1501, 1502, 1503 and 1504 in the inkjet print head 140 cover the effective deposition range 1830' corresponding to the pixel micro-grooves 1830, that is, the number of orifices covered by the effective deposition range is 4.

As shown in FIG. 10 , under a certain ejection frequency and movement speed, each ejection hole can eject 3 ink droplets to the pixel micro-grooves 1830 during the printing process, that is, the number of ink droplets ejected by a single ejection hole is 3.

If 40pL of ink needs to be deposited in the micro-grooves of each pixel, and the volume of the ink droplets ejected by each orifice is 10±0.5pL, for one printing process, this method can be used from 1601-1, 1601-2, …, 1604 4 of the 12 ink droplets are selected to match the volume requirements of the ink deposited in the micro-grooves of each pixel.

Using the characteristics of high-frequency ink jetting of the ink jet print head 130, when the effective deposition range 1830' passes through the printing area, the selected jetting holes 1501, 1502, 1503 and 1504 are driven to jet ink, and the selected 4 ink droplets are deposited to the pixels within the micro-grooves 1830.

Determine whether it is necessary to continue printing, if no, end printing, if yes, move the inkjet print head in the x direction by an integer multiple of the distance between adjacent nozzle holes, or move the printing substrate in the y direction by an integer multiple of the distance between adjacent nozzle holes. Integer times of distance, drive the corresponding nozzle to ink jet for the next printing, until the end of printing.

As shown in FIG. 11 , in this embodiment, the method of moving the inkjet print head is used to perform repeated printing. Moving the inkjet print head 140 along the x-direction to perform repeated printing can multiply the effective deposition area of the long side of the micro-groove for each pixel to cover the number of orifices m. During the first printing, the nozzle holes 1501, 1502, 1503 and 1504 in the inkjet print head 140 are covered within the effective deposition range 1830' corresponding to the pixel micro-grooves 1830; after the first printing, the phase is moved along the x direction. An integer multiple of the spacing between adjacent nozzle holes makes the nozzle holes 1511, 1512, 1513 and 1514 cover the effective deposition range 1830', and the second printing is performed.

Assuming that the effective deposition range of the long side of a single pixel micro-groove covers m orifices, and a single orifice can eject n ink droplets when the width direction of a single pixel micro-groove passes through the printing area during the printing process, then there are m for a single pixel micro-groove. *n ink droplets can be selected to meet the volume requirement of the deposited ink. Further, the effective deposition range of a single pixel micro-groove long side covers the number of orifices m and the number of ink droplets n that a single orifice can eject when the width direction of a single pixel micro-groove passes through the printing area during the printing process can be further improved by certain methods. For the entire printing process, when the inkjet print head is moved once along the x direction (that is, the number of times of printing is 2), the effective deposition range of the long side of the single pixel micro-groove covers the number of orifices increased from m to 2m. When the inkjet print head is moved once along the x direction (that is, the number of prints is 3 times), the number of m is increased to 3m. Increasing the ejection frequency of the inkjet print head or reducing the movement speed of the printing substrate can increase the number of ink droplets that can be ejected by a single nozzle when the width direction of the micro-groove of a single pixel passes through the printing area during the printing process. For example, the ejection frequency can be increased by 2 times. Or reducing the substrate movement speed to 1/2 will increase n to 2n. The comprehensive utilization of the methods of increasing m and n will greatly improve the selection range of the ink droplets deposited in the micro-grooves of a single pixel, thereby improving the printing efficiency.

If the above functions are implemented in the form of software functional units and sold or used as independent products, they may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention can be embodied in the form of a software product in essence, or the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including Several instructions are used to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, Read-Only Memory (ROM, Read-Only Memory), Random Access Memory (RAM, Random Access Memory), magnetic disk or optical disk and other media that can store program codes .

Claims (10)

1. a high-efficiency OLED pixel layer printing method, is characterized in that, comprises the following steps: Measure the volume and velocity of the ink droplets ejected from each orifice under the pre-configured driving waveform, and close the orifice corresponding to the ink drop whose volume deviates from the standard volume pre-configured percentage or more; Calculate the effective deposition range of ink droplets in the pixel micro-grooves according to the volume, velocity, deposition position, deposition time interval, and the wettability and geometric structure of the pixel micro-grooves; Calculate the printing frequency of the inkjet print head and the movement speed of the printing substrate according to the production tact and ink viscosity; Calculate the number of prints according to the pixel micro-groove geometry, orifice inkjet situation, inkjet printhead printing frequency and printing substrate movement speed; According to the number of orifices covered by the effective deposition range, the number of ink droplets ejected by a single orifice, and the volume of the ink droplets, determine the number of orifices driven and the number of ink droplets ejected by the orifices during each printing; Drive the selected orifice to eject ink to deposit ink droplets into the pixel micro-grooves; Determine whether it is necessary to continue printing, if no, end printing, if yes, move the inkjet print head in the x direction or move the printing substrate in the y direction, and drive the corresponding nozzles to ink jet for the next printing until the end of printing. 2 . The high-efficiency OLED pixel layer printing method according to claim 1 , wherein the pre-configured percentage is ±5%. 3 . 3 . The high-efficiency OLED pixel layer printing method according to claim 1 , wherein the inkjet condition of the orifice includes the volume of the ink droplet ejected from the orifice and the working state of the orifice. 4 . 4 . The high-efficiency OLED pixel layer printing method according to claim 3 , wherein the working states of the orifices include normal, scattered, and oblique. 5 . 5 . The high-efficiency OLED pixel layer printing method according to claim 1 , wherein the moving distance of moving the inkjet print head along the x-direction or moving the printing substrate along the y-direction is the distance between adjacent nozzle holes. 6 . integer multiples of . 6 . The high-efficiency OLED pixel layer printing method according to claim 1 , wherein the number of ink droplets ejected by the orifice is determined by the printing frequency of the inkjet printing head and the movement speed of the printing substrate. 7 . 7 . The high-efficiency OLED pixel layer printing method according to claim 6 , wherein the number of ink droplets ejected by the orifice is proportional to the printing frequency of the inkjet print head and inversely proportional to the moving speed of the printing substrate. 8 . 8. A high-efficiency OLED pixel layer printing device, characterized in that it comprises a main control computer, a printing controller, a motion controller, an inkjet print head, and a printing substrate, the main control computer according to any one of claims 1-7. The described method sends control information to control the print controller and the motion controller, the print controller controls the ink jetting of the ink jet print head according to the control information, and the motion controller controls the ink jet print head and the motion controller according to the control information Movement of the printed substrate. 9 . The high-efficiency OLED pixel layer printing device according to claim 8 , wherein the control of the ink jet by the printing controller to control the ink jet of the ink jet print head comprises: selecting and driving the jet holes, and controlling the jet holes to jet out Droplets with the required volume, velocity and jetting angle. 10. A storage medium on which a program is stored, characterized in that, when the program is executed, the method according to any one of claims 1-7 is implemented.

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