A new method for collecting arrayed flying ink droplet images in display jet printing manufacturing

Abstract

The application belongs to the field of visual detection of inkjet printing, and particularly relates to a novel display jet printing manufacturing arrayed flying ink drop image acquisition method, which comprises the following steps: according to the arrangement mode of a large number of jet orifices of an arrayed jet head to be detected, determining the arrangement row number N of an observation device group in an arrayed flying ink drop observation device group, the arrangement number a of a row of observation devices, and the X-direction center offset distance x of the front and rear two rows of observation devices when N is greater than 1 h , so as to be adaptively applied to arrayed jet heads with different arrangement modes of a large number of jet orifices; according to the structural properties of the arrayed jet head to be detected and the observation device group, determining the X-direction center distance x1 of adjacent observation devices required for observation and the device group moving number y required for completing X-direction single pass observation, with the constraints that the same row of devices groups observes the same row of jet orifices and the X-direction single pass observation time is the shortest; and based on x1 and y, performing traversal observation on the jet orifices. The method can adapt to various jet head group arrangement forms and can quickly complete the observation task of a large number of jet orifices of a jet head array.

Description

Technical Field

[0001] This invention belongs to the field of visual inspection of inkjet printing, and more specifically, relates to a novel method for acquiring images of arrayed flying ink droplets in display inkjet printing manufacturing. Background Technology

[0002] Inkjet printing technology is a key technology in new display manufacturing processes. It features contactless and template-free manufacturing characteristics, enabling digital flexible printing under ambient temperature and pressure conditions. This meets the requirements of large-volume, large-area production and is a crucial technology for effectively realizing flexible electronics manufacturing. During inkjet printing, due to the large number of nozzles in the printhead array, and the influence of parameters such as nozzle condition, ink properties, and printing environment, abnormal phenomena such as nozzle clogging, droplet flight deviation, trailing, and droplet volume discrepancies may occur. Furthermore, the consistency of droplet volume ejected from a large number of nozzles can also lead to printing defects on the substrate. When inkjet printing large-size substrates, multiple printheads within the printhead array typically need to operate simultaneously. The number of printheads to be inspected is enormous, and strict cycle time requirements exist. Therefore, highly efficient inspection methods are needed to detect the state of the numerous droplets ejected from the nozzles, effectively controlling print quality.

[0003] Existing methods for measuring inkjet printing droplets mainly include weighing, induction, laser interferometry, and visual measurement. Weighing methods only offer high accuracy in measuring droplet volume and cannot detect the velocity and angle of flying droplets, making them suitable only for verification. Induction methods, when used for real-time detection of arrayed piezoelectric nozzles, can only roughly determine whether ejection has occurred but cannot quantitatively measure flying droplet parameters. Laser interferometry primarily utilizes the phase Doppler principle to analyze flying droplet parameters through interference signals, but it is costly. Existing visual measurement methods mainly rely on stroboscopic photography to observe flying droplets, but typically only a single nozzle is detected at a time; while meeting accuracy requirements, this is inefficient. Currently, there are schemes using multi-camera systems to observe specific targets, but these schemes optimize observation for only a single target. When the target being observed differs significantly from the previous target in terms of arrangement, size, etc., these schemes are difficult to apply directly, resulting in limited applicability and poor universality. Considering that arrayed printheads operate simultaneously in actual production, the number of nozzles to be inspected is enormous, there are strict requirements on the working cycle, and there is a need to adjust the array printhead arrangement for different situations. Designing a high-efficiency and highly universal flying ink droplet detection method based on vision measurement to achieve high-efficiency observation of flying ink droplets ejected from a massive number of nozzles under different printhead array arrangements constitutes a key technical need that urgently needs to be addressed in this field. Summary of the Invention

[0004] To address the shortcomings and improvement needs of existing technologies, this invention provides a novel method for acquiring images of arrayed flying ink droplets in display inkjet printing manufacturing. The aim is to improve the efficiency of acquiring images of flying ink droplets in various large-scale nozzle printing scenarios with different printhead arrays in novel display inkjet printing manufacturing while ensuring image acquisition accuracy.

[0005] To achieve the above objectives, according to one aspect of the present invention, a novel method for acquiring arrayed flying ink droplet images in display inkjet printing manufacturing is provided, comprising:

[0006] S1. Set up an array of flying ink droplet observation devices at a certain distance in the Y direction and parallel to the array of nozzles under test in the X direction; wherein, the number of rows N of observation devices in the device group, the number a of observation devices in a row, and the center offset distance x of the two rows of observation devices in the X direction when N is greater than 1. h All of these are determined by the arrangement of a large number of nozzles in the array of nozzles under test, with the constraint that the length of the X-direction space occupied by each row of observation devices is less than the length L of the X-direction space occupied by each row of nozzles; the X-direction is the direction of the arrangement of a single row of nozzles, and the Y-direction is perpendicular to the X-direction on the horizontal plane;

[0007] S2. Based on the length L of the X-direction space occupied by each row of nozzles in the array of nozzles to be tested, the X-direction distance x2 between adjacent nozzles, and the X-direction external dimension x of the observation device... c The number of observation devices arranged in a row is 'a'. The constraints are: the observation of the same row of nozzles by the same row of devices and the shortest single-trip observation time in the X direction. The X-direction center distance x1 between adjacent observation devices and the number of device group movements y required to complete the single-trip observation in the X direction are determined. The X-direction center distance between adjacent observation devices in the device group is adjusted to the x1.

[0008] S3. Based on the preset target observation row of each observation device, adjust the focal length of each observation device to acquire images of flying ink droplets. After simultaneously acquiring images of flying ink droplets ejected from multiple nozzles, move the observation device group as a whole in the X direction. After completing the number of moves y in the X direction, determine the new target observation row of each observation device. Repeat this step until the traversal observation of flying ink droplets ejected from the array nozzles is completed.

[0009] Furthermore, the focal length of each observation device can be adjusted by moving the vertical height of the observation device in the Z direction, where the Z direction is the direction perpendicular to the horizontal plane.

[0010] Furthermore, in each X-axis single-pass observation, the target observation nozzle rows of each observation device are consistent.

[0011] Furthermore, the X-axis center distance x1 between adjacent observation devices and the number of device group movements y required to complete a single X-axis observation are determined by calculating the following formula:

[0012]

[0013] In the formula, λ, a, b, m, n ∈ Z, λ indicates that x1 and x2 are integer multiples of each other, b indicates that x c x2 and x2 are integer multiples of each other, t represents the one-way observation time in the X direction, t1 represents the time required for the observation device to move once, t2 represents the waiting time after the observation device moves and t3 represents the time required for the observation device to complete a single image acquisition, and [] represents rounding down.

[0014] This invention also provides a novel arrayed flying ink droplet image acquisition device for display inkjet printing manufacturing, used to implement the novel arrayed flying ink droplet image acquisition method for display inkjet printing manufacturing as described above, comprising:

[0015] An array of flying ink droplet observation devices is used to acquire images of flying ink droplets;

[0016] The observation parameter determination module is used to determine the X-axis center distance x1 between adjacent observation devices and the number of device group movements y required to complete a single X-axis observation.

[0017] The mechanical control module is used to adjust the X-axis center distance between adjacent observation devices in the device group;

[0018] The image acquisition and control module is used to control the movement and image acquisition of the arrayed flying ink droplet observation device group.

[0019] Furthermore, each observation device in the arrayed flying ink droplet observation device group is identical and includes a mounting bracket and a camera, lens, mirror assembly and adjuster mounted on the mounting bracket. The adjuster is used to adjust the optical path distance between the camera in the observation device and its observation nozzle in the Z direction to achieve focusing. The Z direction is the direction perpendicular to the horizontal plane.

[0020] The image acquisition and control module includes a stepper motor, which controls the regulator to adjust the position of the observation device in the Z direction.

[0021] Furthermore, each pair of adjacent observation devices is movably connected in the X direction via a connecting shaft. The mechanical control module adjusts the center distance in the X direction between the two adjacent observation devices by controlling the extension and retraction of the connecting shaft.

[0022] This invention also provides a novel method for screening arrayed nozzles in display inkjet printing manufacturing, comprising:

[0023] Using the novel display inkjet printing manufacturing array flying ink droplet image acquisition method described above, flying ink droplet images of each nozzle to be screened are obtained;

[0024] A deep learning image classification network is used to classify the flying ink droplet images of each nozzle. The nozzles corresponding to the flying ink droplet images that are classified as normal are retained as normal nozzles.

[0025] Calculate the droplet volume V of each droplet in the image of the flying ink droplets corresponding to each normal nozzle. l The arithmetic mean of the volumes of all ink droplets is taken as the volume V of ink droplets ejected from the normal nozzle. xij And calculate the ink droplet volume V. l The maximum difference between the two values ​​and the theoretical ejected droplet volume is used to characterize the degree to which the normal nozzle maintains its own consistency ΔI. xij ; Calculate ΔI within a single nozzle xij The volume V of ink droplets ejected by each nozzle that is less than the threshold xij The maximum difference between the values ​​and the theoretical ejected droplet volume is used to characterize the degree to which the printhead maintains its consistency, ΔI. xi And calculate ΔI within a single nozzle. xij The volume of ink droplets ejected by nozzles smaller than the threshold The arithmetic mean of the values ​​is used as the volume of ink droplets ejected by the printhead. Computational array nozzle The volume of ink droplets ejected by each printhead that is less than the threshold The maximum difference between the values ​​and the theoretical ejected droplet volume is used to characterize the degree to which the printhead array maintains its consistency, ΔI. x If ΔI x If it is less than the threshold, then the current... In each nozzle below the threshold All nozzles with nozzles below the threshold are retained, thus completing the screening process.

[0026] Furthermore, the degree to which a normal nozzle maintains its own consistency is expressed as follows:

[0027]

[0028] The degree to which the nozzle maintains its own consistency ΔI xi Represented as:

[0029]

[0030] The degree to which the array nozzles maintain their own consistency ΔI x Represented as:

[0031]

[0032] In the formula, λ1 is the weighting coefficient for consistency of a single nozzle, and V Tλ1 represents the theoretical ejected droplet volume, λ2 represents the uniformity weighting coefficient for a single printhead, and λ3 represents the uniformity weighting coefficient for an array of printheads, where λ3 ≥ λ2 ≥ λ1 ≥ 1.

[0033] Furthermore, the volume V of a single ink droplet l The calculation method is as follows:

[0034]

[0035] In the formula, l represents the l-th ink droplet in a normal jetting image, k represents the k-th slice after a single ink droplet is discretized into slices of thickness Δh along the height Z direction, k∈{1,2,…,M}, and M is a positive integer.

[0036] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0037] (1) This invention proposes a novel, efficient, and flexible method for acquiring images of arrayed flying ink droplets in display inkjet printing manufacturing, targeting a large number of nozzles in an array printhead. First, based on the arrangement of the large number of nozzles in the array printhead under test, and constrained by the length of the X-axis space occupied by each row of observation devices being less than the length L of the X-axis space occupied by each row of nozzles, the following can be determined: the number of rows N of observation devices in the arrayed flying ink droplet observation device group, the number a of observation devices per row, and the X-axis center offset distance x between two rows of observation devices when N is greater than 1. h To adapt to the massive nozzle array with different arrangement methods, this invention proposes a method for acquiring images of flying ink droplets with massive nozzles that can be widely used in various massive nozzle array arrangements. Secondly, based on the structural properties of the nozzle array under test, including the length L of the X-axis space occupied by each row of nozzles in the nozzle array and the X-axis distance x2 between adjacent nozzles, and some structural properties of the observation device group, including the X-axis external dimensions x of a single observation device... c The method involves arranging a row of observation devices ('a') and minimizing the observation time for the same row of nozzles and the single-way observation in the X direction. This determines the required center-to-center distance (x1) between adjacent observation devices in the X direction and the number of device group movements ('y') required to complete a single-way observation in the X direction. Finally, based on the determined x1 and y, a comprehensive observation of the nozzles is performed. This method is highly feasible, accurate, and efficient. Therefore, the method of this invention can adapt to various nozzle group arrangements and can quickly complete the observation of a large number of nozzles in a nozzle array, possessing significant practical engineering application value for monitoring and evaluating the spray state of nozzle arrays. Furthermore, multiple options are available for determining x1 and y, and the target nozzles for each row of observation devices can be defined during observation, offering high flexibility and meeting observation needs under different circumstances.

[0038] (2) The present invention proposes a method for determining x1 and y, namely the above formula. According to the formula, with the shortest planning time for single-row nozzle observation as a constraint, the center distance between each observation device in the X direction is optimized. Compared with the existing visual observation method, this is beneficial to improve the observation efficiency while maintaining high-precision measurement of flying ink droplets.

[0039] (3) In view of the problem of the consistency of ink droplet volume among the large number of nozzles in the printhead array in actual production, the present invention further designs a consistency discrimination method, which distinguishes the consistency of ink droplet volume between nozzles, ink droplet volume between printheads and ink droplet volume between printhead groups. By setting different threshold parameters, nozzles are screened to meet the requirements of new display printing manufacturing under different conditions. Attached Figure Description

[0040] Figure 1 This is a flowchart illustrating a novel method for acquiring arrayed flying ink droplet images in display inkjet printing manufacturing, provided by an embodiment of the present invention.

[0041] Figure 2 This is a schematic diagram of a novel arrayed flying ink droplet image acquisition device for display inkjet printing manufacturing provided by an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of ink droplet morphology discrimination provided in an embodiment of the present invention;

[0043] Figure 4 This is a flowchart of the algorithm for determining the consistency of ink droplet volume ejected from a large number of nozzles in an array printhead, provided in an embodiment of the present invention.

[0044] Figure 5 This is a flowchart illustrating the rapid screening process for a large number of nozzles in an array nozzle provided in an embodiment of the present invention.

[0045] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0046] 11. Mounting base; 12. Camera and its lens; 13. Adjuster; 14. Mounting bracket; 15. Reflector assembly; 21. Nozzle and its motion platform; 22. Surface light source; 23. Surface light source mounting bracket. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0048] Example 1

[0049] A novel method for acquiring images of arrayed flying ink droplets in display inkjet printing manufacturing, such as Figure 1 As shown, it includes:

[0050] S1. Set up an array of flying ink droplet observation devices at a certain distance in the Y direction and parallel to the array of nozzles under test in the X direction; wherein, the number of rows N of observation devices in the device group, the number a of observation devices in a row, and the center offset distance x of the two rows of observation devices in the X direction when N is greater than 1. h All of these are determined by the arrangement of a large number of nozzles in the array of nozzles under test, with the constraint that the length of the X-direction space occupied by each row of observation devices is less than the length L of the X-direction space occupied by each row of nozzles; the X-direction is the direction of the arrangement of a single row of nozzles, and the Y-direction is perpendicular to the X-direction on the horizontal plane;

[0051] S2. Based on the length L of the X-direction space occupied by each row of nozzles in the array of nozzles to be tested, the X-direction distance x2 between adjacent nozzles, and the X-direction external dimension x of the observation device... c The number of observation devices arranged in a row is 'a'. The constraints are: the observation of the same row of nozzles by the same row of devices and the shortest single-trip observation time in the X direction. The X-direction center distance x1 between adjacent observation devices and the number of device group movements y required to complete the single-trip observation in the X direction are determined. The X-direction center distance between adjacent observation devices in the device group is adjusted to the x1.

[0052] S3. Based on the preset target observation row of each observation device, adjust the focal length of each observation device to acquire images of flying ink droplets. After simultaneously acquiring images of flying ink droplets ejected from multiple nozzles, move the observation device group as a whole in the X direction. After completing the number of moves y in the X direction, determine the new target observation row of each observation device. Repeat this step until the traversal observation of flying ink droplets ejected from the array nozzles is completed.

[0053] This embodiment employs an array of flying ink droplet observation devices to simultaneously observe images of flying ink droplets ejected from multiple rows of nozzles. This can be used to calculate the volume parameters of the flying ink droplets ejected from the nozzles, control the movement of the observation device group, and quickly complete the observation of the ejection status of a large number of nozzles in the nozzle array.

[0054] Specifically, this embodiment proposes a novel, efficient, and flexible method for acquiring arrayed flying ink droplet images in display inkjet printing manufacturing, targeting a large number of nozzles in an array printhead. First, based on the arrangement of the large number of nozzles in the array printhead under test, and constrained by the length of the X-axis space occupied by each row of observation devices being less than the length L of the X-axis space occupied by each row of nozzles, the following can be determined: the number of rows N of observation devices in the arrayed flying ink droplet observation device group, the number a of observation devices per row, and the X-axis center offset distance x between two consecutive rows of observation devices when N is greater than 1. hTo adapt to the massive nozzle array with different arrangement methods, this invention proposes a method for acquiring images of flying ink droplets with massive nozzles that can be widely used in various massive nozzle array arrangements. Secondly, based on the structural properties of the nozzle array under test, including the length L of the X-axis space occupied by each row of nozzles in the nozzle array and the X-axis distance x2 between adjacent nozzles, and some structural properties of the observation device group, including the X-axis external dimensions x of a single observation device... c The method involves arranging a row of observation devices ('a') and minimizing the observation time of the same row of nozzles within the same group, along with the requirement of minimizing the single-way observation time in the X-direction. This determines the required center-to-center distance (x1) between adjacent observation devices in the X-direction and the number of device group movements ('y') required to complete a single-way observation in the X-direction. Finally, based on the determined x1 and y, traversal observation of the nozzles is performed. This method is highly feasible, with high accuracy and observation efficiency. Therefore, the method of this invention can adapt to various nozzle group arrangement forms and can quickly complete the observation of a large number of nozzles in a nozzle array, possessing significant practical engineering application value for monitoring and evaluating the spray state of nozzle arrays. Furthermore, since the optical path distance between the observation device and the target nozzle can be adjusted in the Z-direction for focusing, multiple options are available when determining x1 and y. Additionally, the target nozzle for each row of observation devices can be defined during observation, offering high flexibility and meeting observation needs under different circumstances.

[0055] As a preferred embodiment, the working distance of the observation device is achieved by adjusting its position in the Z-direction. The working distance is the optical path distance between the camera and the observation nozzle in the observation device. The focal length of each observation device is adjusted by moving the vertical height of the observation device in the Z-direction, where the Z-direction is the direction perpendicular to the horizontal plane.

[0056] As a preferred option, all observation devices can share a single light source, which is a surface light source that can produce uniform illumination that meets the light source requirements of each camera.

[0057] In each X-axis single-pass observation, the target observation nozzle rows of each observation device can be the same or different, but the preferred option is to be the same.

[0058] A single observation device precisely observes the shape of the flying droplets ejected from the target nozzle. An array of observation devices simultaneously observes the ejection of multiple nozzles. During observation, the array of observation devices is controlled to move multiple times along the X-axis, preferably observing the same row of nozzles. An adjuster can be controlled to adjust the working distance of each observation device using a stepper motor, so that the observation device is precisely aligned with the next row of nozzles to complete the observation of the ejection status. This process is repeated until all nozzles in the nozzle array are observed.

[0059] In specific implementations, for example, when the array of flying ink droplets observation devices is arranged in N rows, the observation devices in each row of the array of flying ink droplets observation devices in the X direction simultaneously observe the state of flying ink droplets ejected by multiple nozzles in the same row in the X direction; or, the observation devices in the same row of the array of flying ink droplets observation devices in the X direction simultaneously observe the state of flying ink droplets ejected by multiple nozzles in the same row in the X direction, and the observation devices in different rows simultaneously observe the state of flying ink droplets ejected by multiple nozzles in different rows, and the observation device group simultaneously observes the nozzles in the N rows before and after the printhead array. For example, when the array of flying ink droplets observation devices is arranged in one row, the observation devices in each row of the array of flying ink droplets observation devices simultaneously observe the state of flying ink droplets ejected by multiple nozzles in the same row in the X direction.

[0060] To be more specific, the following situations can be discussed:

[0061] (1) Arrange the arrayed flying ink droplet observation device group in a row to observe the state of flying ink droplets ejected from the nozzles in the same row of the nozzle array;

[0062] (2) Arrange the arrayed flying ink droplet observation device group in two rows: one observation method is that the arrayed flying ink droplet observation device group observes the state of flying ink droplets ejected from the nozzles in the same row; the other observation method is that the flying ink droplet observation device arranged in the first row is used to observe the first row of nozzles of the nozzle, and the flying ink droplet observation device arranged in the second row is used to observe the second row of nozzles of the nozzle. The observation device group observes the nozzles in the front and back rows of nozzles of the nozzle array at the same time, and the nozzles in the first row of nozzles are located on the side away from the observation device.

[0063] (3) Adjust the arrangement of the arrayed flying ink droplet observation device to N rows: one observation method is that all the arrayed flying ink droplet observation devices observe the state of the nozzles located in the same row; another observation method is that the flying ink droplet observation device arranged in the first row is used to observe the first row of nozzles of the printhead, the flying ink droplet observation device arranged in the second row is used to observe the second row of nozzles of the printhead, and the flying ink droplet observation device arranged in the Nth row is used to observe the Nth row of nozzles of the printhead. The observation device observes the N rows of nozzles before and after the printhead array at the same time.

[0064] Different observation schemes are selected based on actual working conditions to improve the observation efficiency of the large number of nozzles in the nozzle array.

[0065] As a preferred implementation, the X-axis center distance x1 between adjacent observation devices and the number of device group movements y required to complete a single X-axis observation can be determined by calculating the following formula:

[0066]

[0067] In the formula, λ, a, b, m, n ∈ Z, λ indicates that x1 and x2 are integer multiples of each other, b indicates that x c x2 and t represent integer multiples of each other, t represents the one-way observation time in the X direction, t1 represents the time required for the observation device to move once, t2 represents the waiting time after the observation device moves, t3 represents the time required for the observation device to complete a single image acquisition, and [] represents rounding down. In other words, the f() function represents if... If the remainder of the expression is 0, then the result of the function is: If the remainder of the expression is not 0, the result of the function is rounded down and then incremented by 1.

[0068] Based on this formula, the X-direction center spacing between each observation device can be optimized. After obtaining the optimal solution, the X-direction center spacing between adjacent observation devices can be adjusted and the observation task can be executed.

[0069] The optimal solution for the center-to-center distance between each observation device in the X direction is found, which minimizes the observation time for a single row of nozzles. Compared with existing visual observation methods, this method is beneficial for improving observation efficiency while maintaining high-precision measurement of flying ink droplets.

[0070] After obtaining the optimal solution using the above method, the arrangement of each row of the observation device group (a) and the X-direction center distance (x1) between adjacent flying ink droplet observation devices can be adjusted; the second row of the observation device group needs to be offset by an X-direction distance (x1) compared to the first row. h X-axis offset distance x h It is necessary to ensure that the field of view of the second row of observation devices is not blocked by the first row of observation devices, and the value is an integer multiple of the X-direction distance x2 between adjacent nozzles. The same applies to the arrangement of the Nth row of observation devices.

[0071] Example 2

[0072] A novel arrayed flying ink droplet image acquisition device for display inkjet printing manufacturing, used to implement the novel arrayed flying ink droplet image acquisition method for display inkjet printing manufacturing as described in Embodiment 1, including:

[0073] An array of flying ink droplet observation devices is used to acquire images of flying ink droplets;

[0074] The observation parameter determination module is used to determine the X-axis center distance x1 between adjacent observation devices and the number of device group movements y required to complete a single X-axis observation.

[0075] The mechanical control module is used to adjust the X-axis center distance between adjacent observation devices in the device group;

[0076] The image acquisition and control module is used to control the movement and image acquisition of the arrayed flying ink droplet observation device group.

[0077] As a preferred embodiment, each observation device in the arrayed flying ink droplet observation device group is identical and includes a mounting bracket and a camera, lens, mirror assembly and adjuster mounted on the mounting bracket. The adjuster is used to adjust the optical path distance between the camera in the observation device and its observation nozzle in the Z direction to achieve focusing. The Z direction is the direction perpendicular to the horizontal plane.

[0078] The image acquisition and control module includes a stepper electrode, which controls the regulator via a stepper motor to adjust the position of the observation device in the Z direction, thereby adjusting the distance between the camera and the target nozzle so that the distance meets the focal length requirements and the working distance of the observation device can be adjusted.

[0079] The X-axis movement of each observation device is achieved through a mounting base with X-axis (X-axis is the direction of the single row of nozzles) movement and adjustment function.

[0080] like Figure 2 As shown, a single observation device may include a camera and its lens 12, an adjuster 13, a mounting bracket 14, and a reflector assembly 15. The reflector assembly 15 is mounted on the camera and its lens 12 to change the direction of the optical path. The camera and its lens are mounted on the adjuster 13 via the mounting bracket 14. The adjuster 13 has a Z-direction translational degree of freedom, which can adjust the working distance of the observation device. 11 is the mounting base. The nozzle and its motion platform 21 have XYZ-direction translational degrees of freedom to adjust the nozzle's own pose, ensuring that the nozzles remain on the same horizontal plane when the nozzles are arrayed. The surface light source mounting bracket 23 is equipped with a surface light source 22, which has XZ-direction degrees of freedom, and can adjust the position and height of the surface light source to meet the optical path requirements.

[0081] As a preferred embodiment, each pair of adjacent observation devices is movably connected in the X direction via a connecting shaft. The mechanical control module adjusts the center distance in the X direction between the two adjacent observation devices by controlling the extension and retraction of the connecting shaft.

[0082] The number of observation devices is two or more, and the array of observation devices occupies less space in the X-direction than the nozzle array. All observation devices share a single light source, which is a surface light source that can produce uniform illumination that meets the light source requirements of each camera. Each set of observation devices consists of identical cameras, lenses, reflector assemblies, adjusters, and mounting brackets, and the working distance of each device can be freely adjusted. The array of flying ink droplet observation devices can be arranged in a single row or multiple rows according to observation requirements.

[0083] The arrayed flying ink droplet observation device group designed in this embodiment can simultaneously observe the state of flying ink droplets ejected from multiple rows of nozzles. Depending on the arrangement of the arrayed nozzles and observation device group, multiple observation methods can be implemented, ensuring high-precision detection of flying ink droplet motion parameters. Different observation methods can also be selected according to the operating conditions, quickly completing the observation of the ejection state of a massive number of nozzles in the nozzle array. The observation methods include the X-axis center-to-center distance information between adjacent observation devices, the number of single-trip observation moves, and the target observation row information for each row of observation devices in a single trip.

[0084] The rapid detection method for arrayed flying ink droplets applicable to novel display inkjet printing manufacturing according to the present invention can achieve high-efficiency and high-precision detection of the volume of flying ink droplets ejected from a large number of nozzles in a printhead array. By adjusting the arrangement of the arrayed flying ink droplet observation device group, multiple observation methods can be achieved. The X-axis center distance between each observation device can be optimized and the observation time of a single row of nozzles can be planned. Compared with existing visual observation methods, this method is beneficial to improve observation efficiency while maintaining high-precision measurement of flying ink droplets.

[0085] Example 3

[0086] A novel method for screening arrayed nozzles in display inkjet printing manufacturing includes:

[0087] Using a novel display inkjet printing manufacturing array flying ink droplet image acquisition method as described in Example 1, flying ink droplet images of each nozzle to be screened are detected;

[0088] A deep learning image classification network is used to classify the flying ink droplet images of each nozzle. The nozzles corresponding to the flying ink droplet images that are classified as normal are retained as normal nozzles.

[0089] Calculate the droplet volume V of each droplet in the image of the flying ink droplets corresponding to each normal nozzle. l The arithmetic mean of the volumes of all ink droplets is taken as the volume V of ink droplets ejected from the normal nozzle. xij And calculate the ink droplet volume V. l The maximum difference between the two values ​​and the theoretical ejected droplet volume is used to characterize the degree to which the normal nozzle maintains its own consistency ΔI. xij ; Calculate ΔI within a single nozzle xij The volume V of ink droplets ejected by each nozzle that is less than the threshold xij The maximum difference between the values ​​and the theoretical ejected droplet volume is used to characterize the degree to which the printhead maintains its consistency, ΔI. xi And calculate ΔI within a single nozzle. xij The volume V of ink droplets ejected by nozzles smaller than the threshold xij The arithmetic mean of these values ​​is taken as the volume V of ink droplets ejected by the printhead. xi; Calculate ΔI within the array nozzle xi The volume V of ink droplets ejected by each printhead below the threshold xi The maximum difference between the values ​​and the theoretical ejected droplet volume is used to characterize the degree to which the printhead array maintains its consistency, ΔI. x If ΔI x If it is less than the threshold, then the current ΔI will be... xi ΔI in each nozzle less than the threshold xij All nozzles with nozzles below the threshold are retained, thus completing the screening process.

[0090] In summary, the process involves first performing morphological discrimination and volume consistency checks on multiple ink droplets ejected from a single nozzle within an image, eliminating abnormal nozzles with significant volume deviations; then, checking the volume consistency of ejected ink droplets from the remaining nozzles within a single printhead, eliminating nozzles with significant volume deviations from those within the single printhead; finally, checking the volume consistency of ejected ink droplets between printhead array groups, eliminating printheads with significant volume deviations from those within the printhead array group, and retaining the remaining printheads as the working printheads for subsequent printing.

[0091] For example, the following methods can be used for ink droplet morphology discrimination and consistency verification:

[0092] Based on the shape of the ink droplets, such as Figure 3 As shown, ink droplet images are classified into four categories: normal spray, no spray, satellite droplets, and disorder. After fine-tuning and training the deep learning image classification network VGGNet using transfer learning, the collected ink droplet images are classified into four categories: normal spray, no spray, satellite droplets, and disorder. Only images of the normal spray category are retained after classification.

[0093] like Figure 4 As shown, the following method is preferred for verifying the consistency of ink droplet volume ejected by the nozzle, printhead, and printhead array:

[0094] When an array of observation devices observes the same row of nozzles, each single image acquired by a single observation device contains only a single nozzle. The acquired image is labeled x. ij Where i∈{1,2,…,N1} and j∈{1,2,…,N2}, N1 represents the number of nozzles, and N2 represents the number of nozzle holes in a single nozzle. Images and nozzle holes are mapped one-to-one. Based on the nozzle hole numbers corresponding to normal spray images, the remaining nozzle holes with abnormal spray states are masked.

[0095] As a further preferred embodiment, for an image acquired from a nozzle during normal spraying, there are multiple ink droplets, and their volumes are calculated separately. The l-th ink droplet is discretized into a cylinder with a thickness of Δh along the height Z direction, and the cross-section of the slice is considered to have a diameter of d. k The circle, calculated based on the following formula, has an x-th digit. ijThe volume V of the l-th ink droplet ejected from the nozzle l :

[0096]

[0097] Where l represents the l-th ink droplet in the acquired image, k represents the k-th slice after discretizing a single ink droplet, and k∈{1,2,…,M}, the arithmetic mean of the volumes of multiple ink droplets present in the image is calculated as the volume of the ink droplet ejected by the nozzle.

[0098] As a further preferred embodiment, the volume V of the multiple ink droplets ejected from a single nozzle is used... l The maximum difference between the values ​​and the theoretical ejected droplet volume is used to determine the degree to which the nozzle maintains its consistency. Represented as:

[0099]

[0100] In the formula, λ1 is the weighting coefficient for consistency of a single nozzle, and V T This represents the theoretical volume of the ejected ink droplets.

[0101] As a further preferred embodiment, based on the ink droplet volume V within a single printhead nozzle... xij The maximum difference between the values ​​and the theoretical ejected droplet volume is used as the degree to which the printhead maintains its consistency, ΔI. xi , represented as:

[0102]

[0103] In the formula, λ2 is the uniformity weighting coefficient for a single printhead. The arithmetic mean of the droplet volumes of all normal nozzles within a single printhead is calculated as the droplet volume ejected by that printhead.

[0104] As a further preferred embodiment, the ink droplet volume ejected by the printhead is considered. The degree of deviation between the maximum difference and the theoretical ejected droplet volume is used as the degree to which the printhead array maintains its consistency, ΔI. x , represented as:

[0105]

[0106] In the formula, λ3 is the consistency weighting coefficient of the nozzle array group. λ1, λ2 and λ3 can be adjusted according to the actual engineering conditions and meet the requirements of λ3≥λ2≥λ1≥1.

[0107] The degree of consistency With ΔI x All values ​​must be less than a given threshold to indicate compliance with the requirements for new display inkjet printing manufacturing.

[0108] The method in this embodiment performs droplet morphology discrimination, nozzle consistency inspection, printhead consistency inspection, and printhead array inter-group consistency inspection based on the acquired images.

[0109] In practical applications, the overall process can be as follows: Figure 5 As shown, the arrangement of the arrayed flying ink droplet observation device group can be selected according to the nozzle arrangement and the number of arrayed flying ink droplet observation device groups, and the X-direction center spacing between each observation device can be adjusted; the distortion correction calibration of the ink droplet observation device camera is performed, and the operation of the surface light source, observation device group, regulator, and mounting base is controlled to acquire ink droplet images; the acquired ink droplet images are processed, and the consistency of nozzles, nozzles, and nozzle arrays is determined, retaining only the normal state part; and the pattern planning of inkjet printing manufacturing is carried out.

[0110] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for acquiring images of arrayed flying ink droplets in inkjet printing manufacturing, characterized in that, include: S1. An array of flying ink droplet observation devices is set up at a certain distance from the nozzle array under test in the Y direction and parallel to the nozzle array under test in the X direction; wherein, the number of rows N of observation devices in the device group and the number of observation devices in a row are... a And the center offset distance of the two rows of observation devices in the X direction when N is greater than 1. All methods utilize the arrangement of nozzles in the array under test, ensuring that the length of each row of observation devices in the X-axis space is less than the length of each row of nozzles in the X-axis space. L Determined by constraints; the X-axis is the direction of a single row of nozzles, and the Y-axis is perpendicular to the X-axis on the horizontal plane; S2. Based on the length of the X-axis space occupied by each row of nozzles in the array to be tested... L X-axis distance between adjacent nozzles and the X-axis external dimensions of the observation device The number of observation devices arranged in a row, denoted as 'a', is determined by minimizing the observation time of the same row of nozzles within the same row of devices and minimizing the single-trip observation time in the X-direction. The center-to-center distance in the X-direction between adjacent observation devices is then determined. And the number of times the equipment group needs to move to complete a single-way observation in the X direction. y The X-axis center distance between adjacent observation devices in the adjustment device group is as described. ; S3. Based on the preset target observation row of each observation device, adjust the focal length of each observation device to acquire images of flying ink droplets. After simultaneously acquiring images of flying ink droplets ejected from multiple nozzles, move the observation device group as a whole in the X direction. After completing the number of moves y in the X direction, determine the new target observation row of each observation device. Repeat this step until the traversal observation of flying ink droplets ejected from the array nozzles is completed.

2. The method for acquiring arrayed flying ink droplet images in display inkjet printing manufacturing according to claim 1, characterized in that, The focal length of each observation device can be adjusted by moving its vertical height in the Z-direction, where the Z-direction is perpendicular to the horizontal plane.

3. The method for acquiring arrayed flying ink droplet images in display inkjet printing manufacturing according to claim 1, characterized in that, In each X-axis single-pass observation, the target observation nozzle rows of each observation device are consistent.

4. The method for acquiring arrayed flying ink droplet images in display inkjet printing manufacturing according to claim 1, characterized in that, The X-axis center distance between adjacent observation devices is determined by calculating the following formula. And the number of device group movements y required to complete a single-way observation in the X direction: In the formula, , express and It is an integer multiple relationship. express and It is an integer multiple relationship. Indicates the one-way observation time in the X direction. This indicates the time required for a single movement of the observation device. This indicates the time the observation device remains stationary after moving. This indicates the time required for the observation device to complete a single image acquisition. This indicates rounding down to the nearest integer.

5. A device for acquiring images of arrayed flying ink droplets in inkjet printing manufacturing, characterized in that, A method for acquiring arrayed flying ink droplet images in display inkjet printing manufacturing as described in any one of claims 1 to 4, comprising: An array of flying ink droplet observation devices is used to acquire images of flying ink droplets; The observation parameter determination module is used to determine the X-axis center distance between adjacent observation devices. And the number of times the equipment group needs to move to complete a single-way observation in the X direction. y ; The mechanical control module is used to adjust the X-axis center distance between adjacent observation devices in the device group; The image acquisition and control module is used to control the movement and image acquisition of the arrayed flying ink droplet observation device group.

6. The arrayed flying ink droplet image acquisition device in display inkjet printing manufacturing according to claim 5, characterized in that, Each observation device in the arrayed flying ink droplet observation device group is identical and includes a mounting bracket and a camera, lens, mirror assembly and adjuster mounted on the mounting bracket. The adjuster is used to adjust the optical path distance between the camera in the observation device and its observation nozzle in the Z direction to achieve focusing. The image acquisition and control module includes a stepper motor, which controls the regulator to adjust the position of the observation device in the Z direction.

7. The arrayed flying ink droplet image acquisition device for display inkjet printing manufacturing according to claim 5, characterized in that, Each pair of adjacent observation devices is movably connected in the X direction via a connecting shaft. The mechanical control module adjusts the center distance in the X direction between the two adjacent observation devices by controlling the extension and retraction of the connecting shaft.

8. A method for screening arrayed nozzles in display inkjet printing manufacturing, characterized in that, include: Using the arrayed flying ink droplet image acquisition method in display inkjet manufacturing as described in any one of claims 1 to 4, flying ink droplet images of each nozzle to be screened are detected; A deep learning image classification network is used to classify the flying ink droplet images of each nozzle. The nozzles corresponding to the flying ink droplet images that are classified as normal are retained as normal nozzles. Calculate the droplet volume of each droplet in the image of the flying ink droplets corresponding to each normal nozzle. The arithmetic mean of the volumes of all ink droplets is taken as the volume of ink droplets ejected from the normal nozzle. And calculate the ink droplet volume. The maximum difference between the values ​​is used to characterize the degree to which the normal nozzle maintains its consistency, based on the deviation from the theoretical ejected droplet volume. ; Calculate the content within a single nozzle The volume of ink droplets ejected by each nozzle that is less than the threshold The degree to which the maximum difference between the values ​​deviates from the theoretical ejected droplet volume is used to characterize the extent to which the printhead maintains its consistency. And calculate the content within a single nozzle. The volume of ink droplets ejected by nozzles smaller than the threshold The arithmetic mean of the values ​​is used as the volume of ink droplets ejected by the printhead. ;Computational array nozzle The volume of ink droplets ejected by each printhead that is less than the threshold The maximum difference between the values ​​and the theoretical ejected droplet volume is used to characterize the degree to which the printhead array maintains its consistency. ;like If it is less than the threshold, then the current... In each nozzle below the threshold All nozzles with nozzles below the threshold are retained, thus completing the screening process.

9. A method for screening arrayed nozzles in display inkjet printing manufacturing according to claim 8, characterized in that, The degree to which a normal nozzle maintains its own consistency is expressed as: The degree to which the printhead maintains its own consistency Represented as: The degree to which the array nozzles maintain their own consistency Represented as: In the formula, The weighting coefficient for the consistency of a single nozzle. The theoretical volume of the ejected ink droplets. The consistency weighting coefficient for individual nozzles. This is a weighting coefficient for the consistency of the array nozzles. .

10. A method for screening arrayed nozzles in display inkjet printing manufacturing according to claim 8 or 9, characterized in that, The volume of a single ink droplet The calculation method is as follows: In the formula, Indicating the first type of normal jet image A drop of ink. This indicates that a single ink droplet is moved along the height Directional slices are discretized into slices with a thickness of After slicing A slice, , M It is a positive integer.

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