Inkjet drop inspection method on a substrate
By using camera capture and automated image processing, the problems of long inspection time and large errors in inkjet droplet inspection have been solved, enabling fast and reliable inkjet droplet quality detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SYSTEM ENGINEERING MEGA SOLUTION CO LTD
- Filing Date
- 2025-09-23
- Publication Date
- 2026-06-30
AI Technical Summary
In existing technologies, inkjet droplet inspection requires manual visual inspection, which is time-consuming and subject to human error, resulting in low reliability.
The system uses a camera to capture images of the substrate and then uses an automated method to compare the target sub-pixel with the surrounding sub-pixels to determine whether the inkjet droplets are defective. This process includes setting the inspection area, dividing the sub-pixel image, calculating the comparison value, and performing binarization.
It enables automated, rapid, and reliable inspection of inkjet droplets to determine if they are defective, reducing human error and improving inspection efficiency and accuracy.
Smart Images
Figure CN122306686A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for inspecting inkjet droplets on a substrate. Background Technology
[0002] In the manufacturing of display panels, inkjet printing technology uses ink droplets ejected from an inkjet printer to form electrodes or subpixels on substrates such as glass substrates.
[0003] Compared with existing thin film deposition technology or photolithography process, this inkjet printing technology has the advantages of being cost-effective, enabling flexible design, and being suitable for mass production. Therefore, it is now being introduced into the manufacturing of display panels.
[0004] In the process of creating subpixels on one side of a substrate using inkjet printing technology, ink droplets ejected from an inkjet printer fill the subpixels that are formed on one side of the substrate by partitions such as black matrices, thereby creating subpixels.
[0005] Previously, to check whether the inkjet droplets in the subpixels were defective, a camera was used to photograph one side of the substrate on which the subpixels were formed. In addition, the inspector visually examined each image of one side of the substrate captured by the camera to check whether the inkjet droplets in the subpixels were defective.
[0006] Because inspectors visually inspect subpixels for ink droplet defects, this process has historically been time-consuming. Furthermore, visual inspection is susceptible to bias and human error, resulting in low reliability. Summary of the Invention
[0007] The problem that the invention aims to solve
[0008] The technical problem to be solved by the present invention is to provide an ink droplet inspection method on a substrate that automatically checks whether the ink droplets in the sub-pixels are defective after the sub-pixels formed on one side of a substrate are filled with ink droplets ejected from an inkjet printer to form sub-pixels.
[0009] The technical problem to be solved by this invention is not limited to the technical problems mentioned above. Those skilled in the art can clearly understand other technical problems not mentioned through the following description.
[0010] Methods for solving problems
[0011] A method for inspecting inkjet droplets on a substrate according to several embodiments of the present invention for solving the above-mentioned problems may include: a step of filling inkjet droplets ejected from an inkjet printer into a sub-pixel formed on one side of the substrate and constituting a substrate pixel; a step of taking a picture with a camera to obtain a substrate image as an image of one side of the substrate; and a step of automatically inspecting whether the inkjet droplets in the sub-pixel are defective using the substrate image, wherein there are multiple sub-pixels, a given number of the sub-pixels constituting the substrate pixel, and in the step of automatically inspecting whether the inkjet droplets are defective, at least a portion of a target sub-pixel image and a target surrounding sub-pixel image are compared, wherein the target sub-pixel image is an image including the target sub-pixel, the target sub-pixel being any one of the sub-pixels constituting a target substrate pixel, and the target surrounding sub-pixel image is an image including the target surrounding sub-pixels, the target surrounding sub-pixels being the sub-pixels corresponding to the target sub-pixel among the sub-pixels constituting the substrate pixels surrounding the target substrate pixel.
[0012] A method for inspecting inkjet droplets on a substrate according to several embodiments of the present invention, for solving the above-mentioned problems, may include: a step of filling sub-pixels formed on one side of the substrate and constituting substrate pixels with inkjet droplets ejected from an inkjet printer; a step of taking a picture with a camera to obtain a substrate image as an image of one side of the substrate; a step of automatically inspecting whether the inkjet droplets in the sub-pixels are defective using the substrate image; and a step of automatically inspecting the defect type of inkjet droplets in the sub-pixels that are determined to be defective, wherein there are multiple sub-pixels, a given number of the sub-pixels constituting the substrate pixels, and the substrate pixels are multiple, and the method of automatically inspecting whether the inkjet droplets are defective includes: a step of filling sub-pixels formed on one side of the substrate and constituting substrate pixels; a step of automatically inspecting whether the inkjet droplets are defective; and a step of automatically inspecting whether the inkjet droplets are defective. In the step of grading, the substrate image is divided into multiple sub-pixel images, each including the sub-pixel. In the step of automatically checking whether the inkjet droplets are defective, at least a portion of the target sub-pixel image and the target surrounding sub-pixel image are compared. The target sub-pixel image is the sub-pixel image including the target sub-pixel, and the target sub-pixel is any sub-pixel constituting a target substrate pixel as any one of the substrate pixels. The target surrounding sub-pixel image is the sub-pixel image including the target surrounding sub-pixels, and the target surrounding sub-pixels are the sub-pixels that correspond to the target sub-pixel among the sub-pixels constituting the substrate pixels surrounding the target substrate pixel.
[0013] An inkjet droplet inspection method on a substrate according to several embodiments of the present invention for solving the above-mentioned problems may include: a step of filling inkjet droplets ejected from an inkjet printer into sub-pixels formed on one side of the substrate and constituting substrate pixels; a step of capturing an image of the substrate as an image of one side of the substrate using a camera; a step of setting an inspection area in the substrate image; a step of automatically inspecting whether inkjet droplets in the sub-pixels are defective using the inspection area; and a step of automatically inspecting the defect type of inkjet droplets in the sub-pixels that are determined to be defective, wherein there are multiple sub-pixels, a given number of the sub-pixels constituting the substrate pixels, and the substrate pixels are multiple, and the automatic inspection... In the step of determining whether the inkjet droplets are defective, the inspection area is divided into multiple sub-pixel images, each including the sub-pixel. In the step of automatically checking whether the inkjet droplets are defective, at least a portion of the target sub-pixel image and the target surrounding sub-pixel image are compared. The target sub-pixel image is the sub-pixel image including the target sub-pixel, where the target sub-pixel is any sub-pixel constituting any one of the target substrate pixels. The target surrounding sub-pixel image is the sub-pixel image including the target surrounding sub-pixels, where the target surrounding sub-pixels are the sub-pixels among the substrate pixels constituting the target substrate pixel that correspond to the target sub-pixel.
[0014] Specific details of other embodiments are included in the detailed description and accompanying drawings. Attached Figure Description
[0015] Figure 1 This is a diagram illustrating a method for inspecting inkjet droplets on a substrate according to several embodiments of the present invention.
[0016] Figure 2 It is shown in Figure 1 A diagram illustrating the step of filling a sub-pixel formed on one side of the substrate and constituting a substrate pixel with ink droplets ejected from an inkjet printer in a method for inspecting inkjet droplets on a substrate.
[0017] Figure 3 It is shown in Figure 1 The figure shows the steps of obtaining a substrate image, which is an image of one side of the substrate, by taking a picture with a camera in the method for inspecting inkjet droplets on a substrate.
[0018] Figure 4 It is shown in Figure 1 The figure shows the steps of setting the inspection area in the substrate image in the method for inspecting inkjet droplets on a substrate.
[0019] Figure 5 It shows that Figure 4 The image shows a magnified view of a portion of the inspection area.
[0020] Figure 6 Only show Figure 5 The target subpixel image and the subpixel image surrounding the target.
[0021] Figure 7 It is Figure 4 A magnified photograph of a portion of the original image of the inspection area and in Figure 1 The automatic inspection method for inkjet droplets on a substrate involves taking a binarized photograph of the inspection area during the step of inspecting whether inkjet droplets are defective.
[0022] Figure 8 It is a photograph showing unfilled inkjet droplets or underfilled inkjet droplets in target sub-pixels where inkjet droplets are judged to be unqualified.
[0023] Figure 9 This is a photograph showing a target sub-pixel that was incorrectly filled with inkjet droplets in a target sub-pixel that was deemed unqualified by inkjet droplets.
[0024] Explanation of reference numerals in the attached figures
[0025] IP: Inkjet printer; IH: Inkjet head
[0026] NZ: Nozzle ID: Inkjet Droplet
[0027] CM: Camera; GS: Substrate
[0028] BM: separator wall; PX: substrate pixel.
[0029] PXT: Target substrate pixel; SP: Subpixel
[0030] SPT: Target subpixel; SPA: Subpixels surrounding the target.
[0031] R: Red G: Green
[0032] B: Blue SI: Substrate Image
[0033] IR: Inspection area; IS: Subpixel image
[0034] IST: Target subpixel image; ISA: Target surrounding subpixel image.
[0035] IPX: Image pixels IPXT: Target image pixels
[0036] IPXA: Image pixels surrounding the target. Detailed Implementation
[0037] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals are used for the same constituent elements in the drawings, and repeated descriptions thereof are omitted.
[0038] Figure 1 This is a diagram illustrating a method for inspecting inkjet droplets on a substrate according to several embodiments of the present invention.
[0039] refer to Figure 1 The inkjet droplet inspection method on the substrate can automatically check whether the inkjet droplet IDs ejected from the inkjet printer IP and filling a sub-pixel SP formed on one side of a substrate GS such as a glass substrate, constituting a substrate pixel PX, are unqualified. In other words, the inkjet droplet inspection method on the substrate can check whether the sub-pixel SP on the substrate GS is properly filled with inkjet droplet IDs. Furthermore, the inkjet droplet inspection method on the substrate can automatically check the type of unqualified inkjet droplet IDs in sub-pixel SPs where inkjet droplet IDs are determined to be unqualified. In other words, the inkjet droplet inspection method on the substrate can check whether the sub-pixel SPs determined to be unqualified are not filled with inkjet droplet IDs or have insufficient inkjet droplet IDs. Furthermore, the inkjet droplet inspection method on the substrate can check whether inkjet droplet IDs are incorrectly filled in sub-pixel SPs determined to be unqualified.
[0040] Figure 2 It is shown in Figure 1 A diagram illustrating the step of filling a sub-pixel formed on one side of the substrate and constituting a substrate pixel with ink droplets ejected from an inkjet printer in a method for inspecting inkjet droplets on a substrate.
[0041] refer to Figure 1 and Figure 2 In the method for inspecting inkjet droplets on a substrate, firstly, inkjet droplets ID ejected from an inkjet printer IP can be filled into a sub-pixel SP formed on one side of the substrate GS and constituting a substrate pixel PX (S100).
[0042] Subpixels SP can be formed on one side of the substrate GS. The subpixels SP can be formed on one side of the substrate GS by dividing it with partition walls BM, such as black matrices, disposed on one side of the substrate GS. For example, subpixels SP can be formed on the upper surface of the substrate GS by partition walls BM.
[0043] The inkjet printer IP can include an inkjet head IH containing nozzles NZ. Furthermore, ink droplets ID can be ejected through the nozzles NZ of the inkjet head IH and filled into sub-pixels SP. Sub-pixels SP can then be fabricated.
[0044] Subpixels SP can constitute substrate pixels PX. There can be multiple subpixels SP, and a given number of subpixels SP can constitute a substrate pixel PX. Different colors of inkjet droplet IDs can be filled into the given number of subpixels SP constituting the substrate pixel PX. For example, three subpixels SP can constitute one substrate pixel PX. Furthermore, one of the three subpixels SP can be filled with a red (R) inkjet droplet ID, another with a green (G) inkjet droplet ID, and yet another with a blue (B) inkjet droplet ID. In this case, the inkjet printer IP's printhead IH can include a nozzle NZ that ejects red (R) inkjet droplet IDs, a nozzle NZ that ejects green (G) inkjet droplet IDs, and a nozzle NZ that ejects blue inkjet droplet IDs. There can be multiple substrate pixels PX. For example, there can be approximately 800,000 substrate pixels PX. Furthermore, there can be approximately 2,400,000 subpixels SP, which is three times the number of substrate pixels PX.
[0045] Figure 3 It is shown in Figure 1 The figure shows the steps of obtaining a substrate image, which is an image of one side of the substrate, by taking a picture with a camera in the method for inspecting inkjet droplets on a substrate.
[0046] refer to Figure 1 and Figure 3 In the inkjet droplet inspection method on the substrate after inkjet printer IP fills the sub-pixel SP with inkjet droplets ID, a substrate image SI can be obtained by taking a picture with camera CM. The substrate image SI is an image of one side of the substrate GS (S200).
[0047] If the substrate GS is small, the substrate image SI can be obtained by taking a single shot with the camera CM. However, the substrate GS may be too large to obtain the substrate image SI with a single shot. In this case, the substrate image SI can be obtained by taking multiple shots of one side of the substrate GS while moving the camera CM. In other words, the substrate image SI can be obtained by combining multiple images of different parts of one side of the substrate GS. For example, the substrate image SI can be obtained by taking 100 shots of the upper surface of the substrate GS while moving the camera CM. In other words, the substrate image SI can be obtained by combining 100 images of different parts of the upper surface of the substrate GS.
[0048] Figure 4 It is shown in Figure 1 The figure shows the steps of setting the inspection area in the substrate image in the method for inspecting inkjet droplets on a substrate.
[0049] refer to Figure 1 and Figure 4 After obtaining the substrate image SI, in the inkjet droplet inspection method on the substrate, an inspection area IR can be set in the substrate image SI (S300). In the step of setting the inspection area IR in the substrate image SI (S300), the inspection area IR can be set by removing portions of the substrate image SI that are not substrate GS. In other words, the inspection area IR can be an image of the substrate image SI that only retains the substrate GS. For example, the inspection area IR can be set in the substrate image SI by detecting the outline of the substrate GS and deleting the portion of the substrate image SI outside the outline of the substrate GS. By setting the inspection area IR in the substrate image SI in this way, errors that might occur due to portions of the substrate image SI that are not substrate GS when automatically checking whether the inkjet droplet ID in the sub-pixel SP is unqualified can be prevented.
[0050] refer to Figure 1 After setting the inspection area IR in the substrate image SI, in the inkjet droplet inspection method on the substrate, the inspection area IR of the substrate image SI can be used to automatically check whether the inkjet droplet ID in the sub-pixel SP is unqualified (S400).
[0051] Figure 5 It shows that Figure 4 The image shows a magnified view of a portion of the inspection area.
[0052] refer to Figure 5 Multiple sub-pixels SP can be arranged spaced apart from each other in the inspection area IR of the substrate image SI. As described above, a given number of sub-pixels SP can constitute a substrate pixel PX, and different colored inkjet droplet IDs can be filled in the given number of sub-pixels SP constituting the substrate pixel PX. For example, three sub-pixels SP can constitute one substrate pixel PX. Furthermore, one of the three sub-pixels SP can be filled with a red inkjet droplet ID (R), another with a green inkjet droplet ID (G), and yet another with a blue inkjet droplet ID (B).
[0053] The inspection area IR of the substrate image SI can be divided into multiple sub-pixel images IS, each including sub-pixel SP. Furthermore, in the step (S400) of automatically checking whether the inkjet droplet ID is defective, the inspection area IR of the substrate image SI can be divided into multiple sub-pixel images IS, each including sub-pixel SP.
[0054] Subsequently, in the step of automatically checking whether the inkjet droplet ID is unqualified (S400), an image including the target sub-pixel SPT can be selected as the target sub-pixel image IST. The target sub-pixel SPT is any sub-pixel SP constituting the target substrate pixel PXT, and the target substrate pixel PXT is any substrate pixel PX. In other words, a sub-pixel image IS including the target sub-pixel SPT can be selected as the target sub-pixel image IST, where the target sub-pixel SPT is any sub-pixel SP constituting the target substrate pixel PXT, which is any substrate pixel PX.
[0055] Furthermore, in the step of automatically checking whether the inkjet droplet ID is unqualified (S400), an image including the target surrounding sub-pixels SPA can be selected as the target surrounding sub-pixel image ISA. The target surrounding sub-pixels SPA are the sub-pixels SP of the substrate pixels PX surrounding the target substrate pixel PXT that correspond to the target sub-pixel SPT. In other words, a sub-pixel image IS including the target surrounding sub-pixels SPA can be selected as the target surrounding sub-pixel image ISA. The target surrounding sub-pixels SPA are the sub-pixels SP of the substrate pixels PX surrounding the target substrate pixel PXT that correspond to the target sub-pixel SPT. There can be multiple target surrounding sub-pixels SPA, therefore there can also be multiple target surrounding sub-pixel images ISA.
[0056] In addition, in the step (S400) of automatically checking whether the inkjet droplet ID is unqualified, at least a portion of the target subpixel image IST and the target surrounding subpixel image ISA can be compared.
[0057] By comparing at least a portion of the target subpixel image IST and the target surrounding subpixel image ISA, it is possible to check whether the ink droplet ID of the target subpixel SPT in the target subpixel image IST is unqualified. Such a comparison of the target subpixel image IST with at least a portion of the target surrounding subpixel image ISA can be performed on all subpixel images IS included in the inspection area IR. In other words, each of all subpixel images IS included in the inspection area IR can be used as the target surrounding subpixel image ISA, and a comparison of the target subpixel image IST with at least a portion of the target surrounding subpixel image ISA can be performed. Furthermore, it is possible to check whether the ink droplet ID of the subpixel SP is unqualified for all subpixel images IS included in the inspection area IR.
[0058] The color of the inkjet droplet ID filling the target surrounding sub-pixel SPA can be the same as the color of the inkjet droplet ID filling the target sub-pixel SPT. In other words, the target surrounding sub-pixel SPA can be a sub-pixel SP of the substrate pixel PX that constitutes the target substrate pixel PXT, filled with inkjet droplet IDs of the same color as the inkjet droplet IDs filling the target sub-pixel SPT.
[0059] For example, such as Figure 5 As shown, the central substrate pixel PX among the nine substrate pixels PX can be designated as the target substrate pixel PXT. Furthermore, the sub-pixel SP of the target substrate pixel PXT, filled with green inkjet droplets ID, can be designated as the target sub-pixel SPT. Additionally, the sub-pixel image IS including the target sub-pixel SPT can be designated as the target sub-pixel image IST. Furthermore, among the sub-pixels SP of the eight substrate pixels PX surrounding the central substrate pixel PX, the sub-pixels SP filled with green inkjet droplets ID can be designated as the target surrounding sub-pixels SPA. Additionally, the sub-pixel image IS including the target surrounding sub-pixels SPA can be designated as the target surrounding sub-pixel image ISA. Figure 5 In this context, the target surrounding sub-pixels SPA can be eight, and the target surrounding sub-pixel image ISA can also be eight. Furthermore, at least a portion of the target sub-pixel image IST and the eight target surrounding sub-pixel images ISA can be compared.
[0060] Figure 6 Only show Figure 5 The target subpixel image and the subpixel image surrounding the target.
[0061] refer to Figure 6 A subpixel image IS can include multiple image pixels (IPX). Furthermore, since the target subpixel image IST and the target surrounding subpixel image ISA are also subpixel images IS, they can also include multiple image pixels (IPX). For example, a subpixel image IS can include tens to thousands of image pixels (IPX). However, for ease of explanation, we will assume below that a subpixel image IS includes 9 image pixels (IPX). Furthermore, since the target subpixel image IST and the target surrounding subpixel image ISA are also subpixel images IS, we will assume that the target subpixel image IST and the target surrounding subpixel image ISA also include 9 image pixels (IPX).
[0062] In the step (S400) of checking whether the inkjet droplet ID is unqualified, any image pixel IPX of the target sub-pixel image IST can be selected as the target image pixel IPXT, and at least a portion of the target sub-pixel image IST and the target surrounding sub-pixel image ISA can be compared. Furthermore, the image pixel IPX of the target surrounding sub-pixel image ISA corresponding to the target image pixel IPXT can be selected as the target surrounding image pixel IPXA. There can be multiple target surrounding sub-pixel images ISA, therefore there can also be multiple target surrounding pixels IPX.
[0063] In addition, in the step (S400) of checking whether the inkjet droplet ID is unqualified, a comparison value can be obtained, which is the absolute value of the value obtained by subtracting the average of the image values of the surrounding image pixels IPXA from the image value of the target image pixel IPXT.
[0064] The position of the target-surrounding image pixel IPXA in the target-surrounding subpixel image ISA can be the same as the position of the target image pixel IPXT in the target subpixel image IST. In other words, the target-surrounding image pixel IPXA can be located in the same position in the target-surrounding subpixel image ISA as the target image pixel IPXT is located in the target subpixel image IST.
[0065] For example, such as Figure 6 As shown, the target subpixel image IST can include 9 image pixels (IPX). Furthermore, the target surrounding subpixel images ISA can each each include 9 image pixels (IPX). Additionally, the image values of each of the 9 image pixels (IPX) of the target subpixel image IST can be represented according to their position within the target subpixel image IST. Furthermore, the image values of the nine image pixels IPX in the target-surrounding sub-pixel image ISA can be represented as G according to the positions of the target-surrounding sub-pixel image ISA around the target sub-pixel image IST and the positions of the image pixels IPX in the target-surrounding sub-pixel image ISA. ab Here, 'a' represents the position of the target-surrounding sub-pixel image ISA within the target-surrounding sub-pixel image IST, and 'b' represents the position of image pixel IPX within the target-surrounding sub-pixel image ISA. For example, G 11 This represents the image value of the first image pixel IPX in the first target-surrounding subpixel image ISA surrounding the target subpixel image IST.
[0066] like Figure 6In this case, the first image pixel IPX among the nine image pixels IPX of the target sub-pixel image IST can become the target image pixel IPXT. Furthermore, the target surrounding image pixel IPXA can be the first image pixel IPX among the nine image pixels IPX of each of the eight target surrounding sub-pixel images ISA. In this case, the image value of the target image pixel IPXT can be... Furthermore, the image value of the IPXA pixels surrounding the target can be G. 11 G 21 G 31 G 41 G 51 G 61 G 71 and G 81 Furthermore, the absolute value of the comparison value obtained by subtracting the average of the image values of the surrounding image pixels IPXA from the image value of the target image pixel IPXT is expressed as: ,but It can be represented by the following mathematical expression 1.
[0067] [Mathematical Expression 1]
[0068]
[0069] In the step (S400) of automatically checking whether the inkjet droplet ID is unqualified, a comparison value can be calculated for each image pixel IPX included in the target sub-pixel image IST.
[0070] In the step (S400) of automatically checking whether the inkjet droplet ID is unqualified, a comparison value can be calculated sequentially for each image pixel IPX included in the target sub-pixel image IST. For example, for Figure 6 The comparison value of each image pixel IPX of the target subpixel image IST can be obtained sequentially using the following mathematical formula 2.
[0071] [Mathematical Expression 2]
[0072]
[0073] Furthermore, in the step (S400) of automatically checking whether the inkjet droplet ID is unqualified, a comparison value can be calculated simultaneously for each image pixel IPX included in the target sub-pixel image IST. For example, the comparison value can be calculated simultaneously for each image pixel IPX included in the target sub-pixel image IST using the following mathematical formula 3. Figure 6 The comparison value of each image pixel IPX of the target subpixel image IST.
[0074] [Mathematical Expression 3]
[0075]
[0076] Such a comparison value can be obtained for each image pixel IPX of all sub-pixel images IS included in the inspection area IR.
[0077] After calculating the comparison value for each image pixel IPX included in the target sub-pixel image IST, in the step (S400) of automatically checking whether the inkjet droplet ID is unqualified, the ratio of image pixel IPX with a comparison value greater than a given value can be calculated.
[0078] Furthermore, in the step of automatically checking whether the inkjet droplet ID is unqualified (S400), if the ratio of image pixels IPX with a comparison value greater than a given value in the target sub-pixel image IST is less than a given ratio, the inkjet droplet ID of the target sub-pixel SPT can be determined to be normal. If the comparison value is below the given value, the image value of the target image pixel IPXT may be the same as or similar to the average image value of the surrounding image pixels IPXA. Furthermore, if the comparison value is greater than the given value, the image value of the target image pixel IPXT may be different from the average image value of the surrounding image pixels IPXA. Additionally, if the ratio of image pixels IPX with a comparison value greater than the given value in the target sub-pixel image IST is less than the given ratio, the target sub-pixel image IST may be the same as or similar to the average image value of the surrounding sub-pixel images ISA. Furthermore, the inkjet droplet ID of the target sub-pixel SPT may be normal.
[0079] For example, image pixel IPX can have image values from 0 to 255. Additionally, if the proportion of image pixel IPX with a comparison value greater than 10 in the target sub-pixel image IST is less than 35%, then the inkjet droplet ID of the target sub-pixel SPT can be determined to be normal.
[0080] In the step (S400) of automatically checking whether the inkjet droplet ID is unqualified, if the ratio of image pixels IPX with a comparison value greater than a given value in the target sub-pixel image IST is above a given ratio, the inkjet droplet ID of the target sub-pixel SPT can be determined to be unqualified. If the comparison value is below the given value, the image value of the target image pixel IPXT may be the same as or similar to the average image value of the surrounding image pixels IPXA. Furthermore, if the comparison value is greater than the given value, the image value of the target image pixel IPXT may be different from the average image value of the surrounding image pixels IPXA. Additionally, if the ratio of image pixels IPX with a comparison value greater than the given value in the target sub-pixel image IST is above a given ratio, the target sub-pixel image IST may be different from the average image value of the surrounding sub-pixel images ISA. Furthermore, the inkjet droplet ID of the target sub-pixel SPT may be unqualified.
[0081] For example, an image pixel IPX can have an image value from 0 to 255. Additionally, if the proportion of image pixels IPX with a comparison value greater than 10 in the target sub-pixel image IST is 35% or more, the inkjet droplet ID of the target sub-pixel SPT can be deemed unqualified.
[0082] After calculating the comparison value for each image pixel IPX included in the target sub-pixel image IST, in the step of automatically checking whether the inkjet droplet ID is unqualified (S400), the image pixel IPXs of the target sub-pixel image IST can be divided into image pixel IPXs with a comparison value greater than a given value and image pixel IPXs with a comparison value less than the given value. Furthermore, in the step of automatically checking whether the inkjet droplet ID is unqualified (S400), binarization can be performed as follows: the image value of the image pixel IPX with a comparison value greater than the given value is treated as a white image value, and the image value of the image pixel IPX with a comparison value less than the given value is treated as a black image value.
[0083] For example, image pixels IPX can have image values from 0 to 255. Furthermore, a white image value can be 0, and a black image value can be 255. Binarization can also be performed as follows: image pixels IPX with a comparison value greater than 10 are treated as white image values (255), and image pixels IPX with a comparison value less than 10 are treated as black image values (0).
[0084] Figure 7 It is Figure 4 A magnified photograph of a portion of the original image of the inspection area, and in Figure 1 The image shows a binarized photograph of the inspection area in the automatic inspection step of the inkjet droplet inspection method on the substrate to determine whether the inkjet droplets are defective.
[0085] refer to Figure 7 The aforementioned binarization can be performed on the image pixels IPX of all sub-pixel images IS included in the inspection area IR. In sub-pixel images IS with normal inkjet droplet IDs, the image pixel IPX with black image values can be greater than a given ratio. Furthermore, in sub-pixel images IS with unqualified inkjet droplet IDs, the ratio of image pixel IPX with white image values can be greater than a given ratio.
[0086] For example, in a subpixel image IS with a normal inkjet droplet ID, the ratio of image pixels with black image values (IPX) can be greater than 75%. Conversely, in a subpixel image IS with a non-compliant inkjet droplet ID, the ratio of image pixels with white image values (IPX) can be greater than 35%.
[0087] Furthermore, by performing the aforementioned binarization on the image pixels IPX of all sub-pixel images IS included in the inspection region IR, thus achieving... Figure 7 In this way, sub-pixels (SPs) with non-compliant inkjet droplet IDs can be highlighted. Furthermore, sub-pixels (SPs) with non-compliant inkjet droplet IDs can be easily located.
[0088] refer to Figure 1 After determining whether the inkjet droplet ID in the target sub-pixel SPT is unqualified, the inkjet droplet inspection method on the substrate can automatically check the unqualified type of the inkjet droplet ID of the target sub-pixel SPT that is determined to be unqualified (S500).
[0089] In the step (S500) of automatically checking for non-conforming types of inkjet droplet IDs, the average image value of the image pixel IPX of the target sub-pixel image IST of the target sub-pixel SPT, whose inkjet droplet ID is determined to be non-conforming, can be calculated. Furthermore, in the step (S500) of automatically checking for non-conforming types of inkjet droplet IDs, the average image value of the image pixel IPX of the surrounding sub-pixel image ISA can be calculated. Additionally, the average image value of the image pixel IPX of the target sub-pixel image IST can be compared with the average image value of the image pixel IPX of the surrounding sub-pixel image ISA.
[0090] The darker the color of image pixel IPX, the smaller the image value of image pixel IPX can be. Furthermore, in the step (S500) of automatically checking for non-conforming types of inkjet droplet IDs, if the average image value of the target sub-pixel image IST is greater than the average image value of the image pixels IPX of the surrounding sub-pixel images ISA, it can be determined that the target sub-pixel SPT is either not filled with inkjet droplet IDs or is underfilled with inkjet droplet IDs.
[0091] Figure 8 It is a photograph showing unfilled inkjet droplets or underfilled inkjet droplets in a target sub-pixel where inkjet droplets are deemed unqualified.
[0092] refer to Figure 8 If the target sub-pixel SP is not filled with ink droplet ID or is filled with less ink droplet ID, the target sub-pixel image IST can be brighter than the target surrounding sub-pixel image ISA.
[0093] In addition, when the inkjet droplet ID is not filled or is filled in a small amount in the target sub-pixel SPT, the average image value of the image pixel IPX of the target sub-pixel image IST can be greater than the average image value of the image pixel IPX of the surrounding sub-pixel image ISA.
[0094] The darker the color of image pixel IPX, the smaller the image value of image pixel IPX can be. Furthermore, in the step (S500) of automatically checking for non-conforming types of inkjet droplet IDs, if the average image value of the target sub-pixel image IST is less than the average image value of the image pixels IPX of the surrounding sub-pixel images ISA, it can be determined that inkjet droplet IDs have been incorrectly filled in the target sub-pixel SPT.
[0095] Figure 9 This is a photograph showing a target sub-pixel that is incorrectly filled with inkjet droplets, which is considered a defective target sub-pixel.
[0096] refer to Figure 9 If the inkjet droplet ID is incorrectly filled in the target sub-pixel SP, the target sub-pixel image IST may be darker than the target surrounding sub-pixel image ISA.
[0097] In addition, the average image value of the target sub-pixel image IST (image pixel IPX) can be less than the average image value of the surrounding sub-pixel images ISA (image pixel IPX).
[0098] Thus, the non-compliance type of inkjet droplet ID can be automatically checked by comparing the average image value of the target sub-pixel image IST with the average image value of the surrounding sub-pixel image ISA.
[0099] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments and can be manufactured in many different ways. Those skilled in the art will understand that it can be implemented in other specific ways without changing the technical concept or essential features of the present invention. Therefore, it should be understood that the above embodiments are exemplary in all respects and not restrictive.
Claims
1. A method for inspecting inkjet droplets on a substrate, comprising: The step of filling ink droplets ejected from an inkjet printer into a sub-pixel formed on one side of a substrate and constituting a substrate pixel. The step of taking a picture of the substrate using a camera to obtain an image of one side of the substrate; as well as The step of automatically checking whether the inkjet droplets in the sub-pixel are defective using the substrate image. There are multiple sub-pixels, and a given number of these sub-pixels constitute the substrate pixels. There are multiple substrate pixels. In the step of automatically checking whether the inkjet droplets are defective, at least a portion of the target sub-pixel image and the target surrounding sub-pixel image are compared. The target sub-pixel image is an image that includes the target sub-pixel, which is any one of the sub-pixels constituting a target substrate pixel as any one of the substrate pixels. The target surrounding sub-pixel image is an image that includes the target surrounding sub-pixels, which are the sub-pixels that correspond to the target sub-pixel among the sub-pixels constituting the substrate pixels surrounding the target substrate pixel.
2. The method for inspecting inkjet droplets on a substrate according to claim 1, wherein, The color of the inkjet droplets filling the sub-pixels surrounding the target is the same as the color of the inkjet droplets filling the target sub-pixels.
3. The method for inspecting inkjet droplets on a substrate according to claim 1, wherein, The target sub-pixel image and the target surrounding sub-pixel image comprise multiple image pixels.
4. The method for inspecting inkjet droplets on a substrate according to claim 3, wherein, In the step of automatically checking whether the inkjet droplets are defective, a comparison value is calculated. The comparison value is the absolute value of the value obtained by subtracting the average of the image values of the surrounding image pixels from the image value of the target image pixel. The target image pixel is any one of the image pixels in the target sub-pixel image, and the surrounding image pixels are the image pixels of the surrounding sub-pixel image corresponding to the target image pixel.
5. The method for inspecting inkjet droplets on a substrate according to claim 4, wherein, The position of the image pixels surrounding the target in the sub-pixel image surrounding the target is the same as the position of the image pixels surrounding the target in the sub-pixel image.
6. The method for inspecting inkjet droplets on a substrate according to claim 4, wherein, In the step of automatically checking whether the inkjet droplets are defective, the comparison value is calculated sequentially for each of the image pixels included in the target sub-pixel image.
7. The method for inspecting inkjet droplets on a substrate according to claim 4, wherein, In the step of automatically checking whether the inkjet droplets are defective, the comparison value is simultaneously calculated for each of the image pixels included in the target sub-pixel image.
8. The method for inspecting inkjet droplets on a substrate according to claim 4, wherein, In the step of automatically checking whether the inkjet droplets are defective, The comparison value is calculated for each of the image pixels included in the target sub-pixel image. If the ratio of image pixels whose comparison value is greater than a given value is less than a given ratio, then the inkjet droplets of the target sub-pixel are determined to be normal. If the ratio of the image pixels whose comparison value is greater than a given value is above the given ratio, then the inkjet droplets of the target sub-pixel are determined to be unqualified.
9. The method for inspecting inkjet droplets on a substrate according to claim 4, wherein, In the step of automatically checking whether the inkjet droplets are defective, The comparison value is calculated for each of the image pixels included in the target sub-pixel image. The image pixels of the target sub-pixel image are divided into image pixels whose comparison value is greater than a given value and image pixels whose comparison value is less than the given value.
10. The method for inspecting inkjet droplets on a substrate according to claim 9, wherein, In the step of automatically checking whether the inkjet droplets are defective, The image values of image pixels whose comparison values are greater than a given value are designated as white image values, and the image values of image pixels whose comparison values are less than a given value are designated as black image values.
11. The method for inspecting inkjet droplets on a substrate according to claim 8, wherein, The method for inspecting inkjet droplets on the substrate further includes: The step of automatically checking the non-conformity type of inkjet droplets of the target sub-pixel that are determined to be non-conforming.
12. The method for inspecting inkjet droplets on a substrate according to claim 11, wherein, The darker the color of an image pixel, the smaller its image value. In the step of automatically checking the non-conforming type of the inkjet droplets, If the average image value of the image pixels of the target sub-pixel image for which inkjet droplets are determined to be unqualified is greater than the average image value of the image pixels of the surrounding sub-pixels, then it is determined that the target sub-pixel is either not filled with inkjet droplets or is underfilled with inkjet droplets. If the average image value of the image pixels of the target sub-pixel image is less than the average image value of the image pixels of the sub-pixels surrounding the target, then it is determined that inkjet droplets are incorrectly filled in the target sub-pixel.
13. The method for inspecting inkjet droplets on a substrate according to claim 1, wherein, The method for inspecting inkjet droplets on the substrate further includes: The step of setting the inspection area in the substrate image. In the step of automatically checking whether the inkjet droplets are defective, the inspection area is used to automatically check whether the inkjet droplets in the sub-pixel are defective.
14. The method for inspecting inkjet droplets on a substrate according to claim 13, wherein, In the step of setting the inspection area, the inspection area is set by removing portions that are not the substrate from the substrate image.
15. A method for inspecting inkjet droplets on a substrate, comprising: The step of filling ink droplets ejected from an inkjet printer into a sub-pixel formed on one side of a substrate and constituting a substrate pixel. The step of taking a picture of the substrate using a camera to obtain an image of one side of the substrate; The step of automatically checking whether the inkjet droplets in the sub-pixel are defective using the substrate image; as well as The step of automatically checking the type of defect in the inkjet droplets of the sub-pixel that are determined to be defective. There are multiple sub-pixels, and a given number of these sub-pixels constitute the substrate pixels. There are multiple substrate pixels. In the step of automatically checking whether the inkjet droplets are defective, the substrate image is divided into multiple sub-pixel images, each including the sub-pixel. In the step of automatically checking whether the inkjet droplets are defective, at least a portion of the target sub-pixel image and the target surrounding sub-pixel image are compared. The target sub-pixel image is the sub-pixel image that includes the target sub-pixel, and the target sub-pixel is any one of the sub-pixels constituting a target substrate pixel as any one of the substrate pixels. The target surrounding sub-pixel image is the sub-pixel image that includes the target surrounding sub-pixels, and the target surrounding sub-pixels are the sub-pixels that correspond to the target sub-pixel among the sub-pixels constituting the substrate pixels surrounding the target substrate pixel.
16. The method for inspecting inkjet droplets on a substrate according to claim 15, wherein, The sub-pixel image includes multiple image pixels. The target sub-pixel image and the target surrounding sub-pixel image also include multiple image pixels.
17. The method for inspecting inkjet droplets on a substrate according to claim 16, wherein, In the step of automatically checking whether the inkjet droplets are defective, a comparison value is calculated. The comparison value is the absolute value of the value obtained by subtracting the average of the image values of the surrounding image pixels from the image value of the target image pixel. The target image pixel is any one of the image pixels in the target sub-pixel image, and the surrounding image pixels are the image pixels of the surrounding sub-pixel image corresponding to the target image pixel.
18. The method for inspecting inkjet droplets on a substrate according to claim 17, wherein, In the step of automatically checking whether the inkjet droplets are defective, The comparison value is calculated for each of the image pixels included in the target sub-pixel image. If the ratio of image pixels whose comparison value is greater than a given value is less than a given ratio, then the inkjet droplets of the target sub-pixel are determined to be normal. If the ratio of the image pixels whose comparison value is greater than a given value is above the given ratio, then the inkjet droplets of the target sub-pixel are determined to be unqualified.
19. The method for inspecting inkjet droplets on a substrate according to claim 18, wherein, The darker the color of an image pixel, the smaller its image value. In the step of automatically checking the non-conforming type of the inkjet droplets, If the average image value of the image pixels of the target sub-pixel image for which inkjet droplets are determined to be unqualified is greater than the average image value of the image pixels of the surrounding sub-pixels, then it is determined that the target sub-pixel is either not filled with inkjet droplets or is underfilled with inkjet droplets. If the average image value of the image pixels of the target sub-pixel image is less than the average image value of the image pixels of the sub-pixels surrounding the target, then it is determined that inkjet droplets are incorrectly filled in the target sub-pixel.
20. A method for inspecting inkjet droplets on a substrate, comprising: The step of filling ink droplets ejected from an inkjet printer into a sub-pixel formed on one side of a substrate and constituting a substrate pixel. The step of taking a picture of the substrate using a camera to obtain an image of one side of the substrate; The step of setting the inspection area in the substrate image; The step of automatically checking whether the ink droplets in the sub-pixel are defective using the inspection area; as well as The step of automatically checking the type of defect in the inkjet droplets of the sub-pixel that are determined to be defective. There are multiple sub-pixels, and a given number of these sub-pixels constitute the substrate pixels. There are multiple substrate pixels. In the step of automatically checking whether the inkjet droplets are defective, the inspection area is divided into multiple sub-pixel images, each including the sub-pixel. In the step of automatically checking whether the inkjet droplets are defective, at least a portion of the target sub-pixel image and the target surrounding sub-pixel image are compared. The target sub-pixel image is the sub-pixel image that includes the target sub-pixel, and the target sub-pixel is any one of the sub-pixels constituting a target substrate pixel as any one of the substrate pixels. The target surrounding sub-pixel image is the sub-pixel image that includes the target surrounding sub-pixels, and the target surrounding sub-pixels are the sub-pixels that correspond to the target sub-pixel among the sub-pixels constituting the substrate pixels surrounding the target substrate pixel.