Method for measuring a droplet

Abstract

Disclosed is a method of measuring a droplet, including: discharging a droplet onto a substrate; imaging the droplet with a measurement section spaced apart from the droplet in one direction; measuring the distance between the liquid drop and the measuring part; and correcting the area of the droplet.

Description

Technical Field

[0001] The present disclosure relates to a method for measuring a droplet and a droplet measurement system. Background Art

[0002] In the process of manufacturing a display device, an inkjet printing device can be used to form a light emitting layer or a color filter layer, etc.

[0003] The inkjet printing device may include an inkjet head, and the inkjet head may discharge an organic material, a color filter material, an insulating material, etc. through a nozzle. In this case, the inkjet printing device may perform printing by discharging droplets from the nozzle of the inkjet head toward the object while changing the relative positions of the inkjet head and the object. Summary of the invention

[0004] Embodiments may provide a method of measuring a droplet with improved reliability.

[0005] Embodiments may provide a droplet measurement system using the method of measuring a droplet.

[0006] An embodiment of a method of measuring a droplet includes: discharging the droplet onto a substrate; imaging the droplet using a measurement portion spaced apart from the droplet in one direction; measuring a distance between the droplet and the measurement portion; and correcting an area of ​​the droplet.

[0007] In an embodiment, the measuring of the distance between the droplet and the measuring portion may include measuring a distance by which the droplet deviates from a focal position of the measuring portion.

[0008] In an embodiment, the measurement of the distance by which the droplet deviates from the focal position of the measuring portion may include determining a grayscale change of an edge portion of a first image of the droplet imaged by the measuring portion.

[0009] In an embodiment, in determining the grayscale change of the edge portion of a first image of a droplet imaged by the measuring portion, the grayscale change of the edge portion of the first image can be compared with the grayscale change of the edge portion of a second image of the droplet imaged by the measuring portion at the focal position.

[0010] In an embodiment, as the droplet deviates from the focal position of the measuring portion, the width of the grayscale change of the edge portion of the first image may increase.

[0011] In an embodiment, the measuring of the distance between the droplet and the measuring portion may further include measuring a direction in which the droplet deviates from a focal position of the measuring portion.

[0012] In an embodiment, the measuring of the direction in which the droplet deviates from the focal position of the measuring portion may include determining the grayscale of a feature point of the first image of the droplet.

[0013] In an embodiment, in determining the grayscale of the feature point of the first image of the droplet, the grayscale of the feature point of the first image may be compared with the grayscale of the feature point of the second image.

[0014] In an embodiment, the feature point may be a part of an edge portion of the first image.

[0015] In an embodiment, the feature point may be a part of a central portion of the first image.

[0016] In an embodiment, the measuring of the distance between the droplet and the measuring portion may further include measuring an area of ​​the first image of the droplet.

[0017] In an embodiment, in the measurement of the area of ​​the first image of the droplet, the area of ​​the first image may be compared with the area of ​​the second image.

[0018] In an embodiment, in the correction of the area of ​​the droplet, the area of ​​the first image may be corrected to the actual area of ​​the droplet based on the distance and direction in which the droplet deviates from the focal position of the measurement portion.

[0019] In an embodiment, the method may further include evaluating the discharge volume of the droplet based on the actual area of ​​the droplet.

[0020] In an embodiment, the method may further include feedback-controlling the focal position of the measuring portion based on a distance by which the droplet deviates from the focal position of the measuring portion and a direction in which the droplet deviates from the focal position of the measuring portion.

[0021] An embodiment of a droplet measurement system includes: an inkjet head that discharges droplets onto a substrate; a measuring portion that is spaced apart from the droplets in one direction and images the droplets; and a correction portion that measures the distance between the droplets and the measuring portion and corrects the area of ​​the droplets imaged by the measuring portion.

[0022] In an embodiment, the correction section may measure the distance between the droplet and the measurement section based on the area of ​​the droplet imaged by the measurement section, the distance the droplet deviates from the focal position of the measurement section, and the direction in which the droplet deviates from the focal position of the measurement section.

[0023] In an embodiment, the correction section may measure the distance by which the droplet deviates from the focal position of the measurement section based on a grayscale change of an edge portion of the droplet imaged by the measurement section.

[0024] In an embodiment, the correction section may measure the direction in which the droplet deviates from the focal position of the measurement section based on the grayscale of a feature point of the droplet imaged by the measurement section.

[0025] In an embodiment, the droplet measurement system may further include a control section that feedback controls a focus position of the measurement section based on a distance between the droplet and the measurement section.

[0026] In a method for measuring a droplet according to an embodiment of the present disclosure, the area of ​​the droplet imaged by the measuring portion can be corrected to the actual area of ​​the droplet based on the distance by which the droplet deviates from the focal position of the measuring portion and the direction in which the droplet deviates from the focal position of the measuring portion. Accordingly, even if the droplet deviates from the focal position of the measuring portion, the error between the imaged area of ​​the droplet and the actual area of ​​the droplet can be automatically corrected, so that the discharge amount of the droplet can be evaluated based on the actual area of ​​the droplet. Therefore, even if the upper surface of the target substrate on which the droplet is placed is uneven, the discharge amount of the droplet can be controlled to be uniform, so that the quality of the product including the droplet can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a perspective view showing a droplet measurement system according to an embodiment of the present disclosure.

[0028] Figure 2 is a flow chart of a method for measuring a droplet according to an embodiment of the present disclosure.

[0029] Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Fig. 9 and Fig.10 It is used to explain Figure 2 A view of a method of measuring droplets. DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals are used for the same components, and redundant descriptions of the same components will be omitted.

[0031] Figure 1 is a perspective view showing a droplet measurement system according to an embodiment of the present disclosure.

[0032] refer to Figure 1 The droplet measurement system 1000 may include a stage ST, an inkjet head 100 , a measuring part 200 , a correction part 300 , and a control part 400 .

[0033] The stage ST may be parallel to a plane defined by the first direction DR1 and the second direction DR2 intersecting the first direction DR1. For example, the first direction DR1 and the second direction DR2 may be perpendicular to each other.

[0034] The stage ST may support a target substrate SUB. The droplets DP may be placed on the target substrate SUB to form a pattern. The upper surface of the target substrate SUB on which the droplets DP are placed may not be flat. For example, the target substrate SUB may be a substrate or a film.

[0035] The inkjet head 100 may be spaced apart from the stage ST in a third direction DR3 intersecting each of the first direction DR1 and the second direction DR2. For example, the third direction DR3 may be perpendicular to each of the first direction DR1 and the second direction DR2.

[0036] The inkjet head 100 may discharge droplets DP onto a target substrate SUB disposed on the stage ST. The inkjet head 100 may include a plurality of nozzles that discharge droplets DP toward the target substrate SUB in a direction opposite to the third direction DR3. The plurality of nozzles may be arranged along the first direction DR1.

[0037] The inkjet head 100 may move along the second direction DR2. That is, the inkjet head 100 may move in the second direction DR2 and may discharge droplets DP onto the target substrate SUB. Specifically, the inkjet head 100 may discharge droplets DP in a stopped state, and then may move a predetermined distance in the second direction DR2 to discharge droplets DP again in a stopped state. However, the present disclosure is not limited thereto, and the inkjet head 100 may move and repeatedly discharge droplets DP.

[0038] The droplets DP discharged onto the target substrate SUB may be solidified to form a pattern. The droplets DP discharged from the inkjet head 100 may form a pattern along the first direction DR1 and the second direction DR2.

[0039] The measuring part 200 may be spaced apart from the stage ST in the third direction DR3. The measuring part 200 may image (or capture an image) at a focal position of the measuring part 200 in a direction opposite to the third direction DR3. That is, the image captured by the measuring part 200 may refer to an image on a plane defined by the first direction DR1 and the second direction DR2. For example, the measuring part 200 may include a camera module.

[0040] In an embodiment, the measuring part 200 may detect the droplets DP discharged onto the target substrate SUB. In addition, the measuring part 200 may image the droplets DP on the target substrate SUB. That is, the measuring part 200 may capture an image of the droplets DP on the above plane.

[0041] The correction part 300 may measure the distance between the droplet DP and the measuring part 200 based on the image of the droplet DP captured by the measuring part 200. In this case, the distance between the droplet DP and the measuring part 200 may refer to the length in the third direction DR3 from the droplet DP to the measuring part 200. Since the upper surface of the target substrate SUB is not flat, the distance between the droplet DP and the measuring part 200 may vary depending on the position where the droplet DP is disposed on the target substrate SUB.

[0042] In addition, the correction part 300 may correct the area imaged by the measuring part 200 to the actual area of ​​the droplet DP. Since the distance between the droplet DP and the measuring part 200 changes, the droplet DP may deviate from the focal position of the measuring part 200. In this case, the image of the droplet DP may be blurred, and an error may occur between the imaged area of ​​the droplet DP and the actual area of ​​the droplet DP. That is, the imaged area of ​​the droplet DP may change according to the distance between the droplet DP and the measuring part 200. The correction part 300 may correct the error between the imaged area of ​​the droplet DP and the actual area of ​​the droplet DP.

[0043] The control section 400 may control the focal position of the measuring section 200. Specifically, the control section 400 may control the focal position of the measuring section 200 based on the distance between the droplet DP and the measuring section 200. Accordingly, even when the type or placement position of the droplet DP discharged onto the target substrate SUB is changed, the focal position of the measuring section 200 may be adjusted.

[0044] exist Figure 1 , the measuring section 200, the correction section 300, and the control section 400 are shown as having separate configurations, but the present disclosure is not limited thereto. Alternatively, the measuring section 200, the correction section 300, and the control section 400 may have one configuration or two configurations.

[0045] Figure 2 is a flow chart of a method for measuring a droplet according to an embodiment of the present disclosure. Figures 3 to 10 It is used to explain Figure 2 A view of a method of measuring droplets.

[0046] refer to Figures 2 to 10 The method S1000 for measuring droplets described herein can be referred to as Figure 1 That is, the droplet measurement system 1000 can use the reference Figures 2 to 10 The method for measuring a droplet S1000 is described. Therefore, redundant descriptions will be omitted or simplified.

[0047] refer to Figure 2 and Figure 3In the method of measuring droplets S1000, the inkjet head 100 may discharge droplets DP onto the target substrate SUB (step S100). The droplets DP may be discharged from the inkjet head 100 in a direction opposite to the third direction DR3 and may be disposed on the target substrate SUB.

[0048] refer to Figure 2 and Figure 4 In the method S1000 for measuring a droplet, the measuring part 200 may image the droplet DP on the target substrate SUB (step S200). The measuring part 200 may be spaced apart from the droplet DP in the third direction DR3. That is, the measuring part 200 may capture an image of the droplet DP viewed from a direction opposite to the third direction DR3.

[0049] refer to Figure 1 , Figure 2 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Fig. 9 and Fig.10 In the method S1000 for measuring a liquid droplet, the calibration unit 300 may measure the distance between the liquid droplet DP and the measuring unit 200 (step S300 ).

[0050] In this case, the correction part 300 may compare the first image IM1 which is a captured image of the droplet DP with the second image IM2 which is a reference image of the droplet DP. Here, the first image IM1 may be an image of the droplet DP captured by the measuring part 200, and the second image IM2 may be an image of the droplet DP captured by the measuring part 200 at a focal position of the measuring part 200.

[0051] For example, if the first image IM1 is an image in which a droplet DP deviated from a focus position is captured, the first image IM1 may be an out-of-focus image, and the second image IM2 may be an in-focus image. That is, the first image IM1 may be a relatively blurred image. For another example, if the first image IM1 is an image in which a droplet DP at a focus position is captured, each of the first image IM1 and the second image IM2 may be an in-focus image.

[0052] In the embodiment, in the measurement of the distance between the droplet DP and the measuring unit 200 (step S300), the correction unit 300 may measure the area of ​​the first image IM1 (step S310). In this case, the area of ​​the first image IM1 may be compared with the area of ​​the second image IM2 (see Figure 6 ).

[0053] When comparing the area of ​​the first image IM1 with the area of ​​the second image IM2, the area of ​​the first image IM1 may be different from or equal to the area of ​​the second image IM2. For example, if the droplet DP deviates from the focal position in a direction close to the measuring portion 200, the area of ​​the first image IM1 may be greater than the area of ​​the second image IM2. For another example, if the droplet DP deviates from the focal position in a direction away from the measuring portion 200, the area of ​​the first image IM1 may be smaller than the area of ​​the second image IM2. For another example, if the droplet DP does not deviate from the focal position, the area of ​​the first image IM1 may be equal to the area of ​​the second image IM2.

[0054] In an embodiment, in the measurement of the distance between the droplet DP and the measuring part 200 (step S300), the correction part 300 may measure the distance by which the droplet DP deviates from the focal position of the measuring part 200 (step S320). In this case, the grayscale change of the first edge portion EP1 of the first image IM1 may be determined. In addition, the grayscale change of the first edge portion EP1 of the first image IM1 may be compared with the grayscale change of the second edge portion EP2 of the second image IM2.

[0055] When comparing the grayscale change of the first edge portion EP1 of the first image IM1 with the grayscale change of the second edge portion EP2 of the second image IM2, the first edge portion EP1 of the first image IM1 may have a first width WD1 of the grayscale change, and the second edge portion EP2 of the second image IM2 may have a second width WD2 of the grayscale change. The first width WD1 of the grayscale change may be greater than or equal to the second width WD2 of the grayscale change.

[0056] For example, if the droplet DP deviates from the focal position of the measuring portion 200, the first image IM1 may be a relatively blurred image, and therefore, the first width WD1 of the grayscale change may be greater than the second width WD2 of the grayscale change. In addition, as the droplet DP deviates from the focal position of the measuring portion 200, the first width WD1 of the grayscale change of the first edge portion EP1 of the first image IM1 may increase. That is, the first width WD1 of the grayscale change of the first edge portion EP1 may increase as the droplet DP moves in a direction close to the measuring portion 200 (e.g., Figure 8 The horizontal axis (-) direction of the measuring part 200 or the direction away from the measuring part 200 (for example, Figure 8 The value increases as it deviates from the focal position in the (+) direction of the horizontal axis.

[0057] For another example, if the droplet DP does not deviate from the focal position of the measuring part 200 , the first width WD1 of the grayscale change may be equal to the second width WD2 of the grayscale change.

[0058] That is, the distance that the droplet DP deviates from the focal position of the measuring part 200 can be measured based on the first width WD1 of the grayscale change of the first edge portion EP1 of the first image IM1 (see FIG. 2 ). Figure 7 and Figure 8 ).

[0059] In an embodiment, in the measurement of the distance between the droplet DP and the measuring part 200 (step S300), the correction part 300 may measure the direction in which the droplet DP deviates from the focal position of the measuring part 200 (step S330). In this case, the grayscale of the first feature point FP1 of the first image IM1 may be determined. In addition, the grayscale of the first feature point FP1 of the first image IM1 may be compared with the grayscale of the second feature point FP2 of the second image IM2.

[0060] When the grayscale of the first feature point FP1 of the first image IM1 is compared with the grayscale of the second feature point FP2 of the second image IM2, the grayscale value of the first feature point FP1 may be different from or equal to the grayscale value of the second feature point FP2. For example, if the droplet DP deviates from the focus position, the grayscale value of the first feature point FP1 may be less than the grayscale value of the second feature point FP2. For another example, if the droplet DP does not deviate from the focus position, the grayscale value of the first feature point FP1 may be equal to the grayscale value of the second feature point FP2.

[0061] The first feature point FP1 and the second feature point FP2 may be portions that compare the grayscale of the first image IM1 with the grayscale of the second image IM2. For example, the first feature point FP1 may be a portion of the first edge portion EP1 of the first image IM1, and the second feature point FP2 may be a portion of the second edge portion EP2 of the second image IM2. For another example, the first feature point FP1 may be a portion of the central portion of the first image IM1, and the second feature point FP2 may be a portion of the central portion of the second image IM2. However, the present disclosure is not limited thereto, and the first feature point FP1 and the second feature point FP2 may be portions that present the grayscale difference between the first image IM1 and the second image IM2.

[0062] In an embodiment, when comparing the grayscale of the first feature point FP1 of the first image IM1 with the grayscale of the second feature point FP2 of the second image IM2 , the spherical aberration of the lens included in the measuring part 200 may be used.

[0063] Specifically, the grayscale of the first feature point FP1 when the droplet DP deviates from the focus position in a direction close to the measuring portion 200 may be different from the grayscale of the first feature point FP1 when the droplet DP deviates from the focus position in a direction away from the measuring portion 200. In other words, even if the distance by which the droplet DP deviates from the focus position in a direction close to the measuring portion 200 and the distance by which the droplet DP deviates from the focus position in a direction away from the measuring portion 200 have the same value, the grayscale of the first feature point FP1 may have different values.

[0064] That is, the direction in which the droplet DP deviates from the focal position of the measuring section 200 can be measured based on the grayscale of the first feature point FP1 of the first image IM1 (see FIG. 2 ). Fig. 9 and Fig.10 ).

[0065] exist Figure 5 , the measurement of the area of ​​the first image IM1 of the droplet DP (step S310), the measurement of the distance that the droplet DP deviates from the focus position (step S320), and the measurement of the direction that the droplet DP deviates from the focus position (step S330) are shown as being performed sequentially, but the present disclosure is not limited thereto. Alternatively, the order in which the measurement of the area of ​​the first image IM1 of the droplet DP (step S310), the measurement of the distance that the droplet DP deviates from the focus position (step S320), and the measurement of the direction that the droplet DP deviates from the focus position (step S330) are performed may be changed, or the measurement of the area of ​​the first image IM1 of the droplet DP (step S310), the measurement of the distance that the droplet DP deviates from the focus position (step S320), and the measurement of the direction that the droplet DP deviates from the focus position (step S330) may be performed simultaneously.

[0066] Return to reference Figure 1 , Figure 2 and Figure 6 In the method S1000 for measuring a droplet, the correction unit 300 may correct the area of ​​the droplet DP (step S400).

[0067] The correction unit 300 may correct the area of ​​the first image IM1 to the actual area of ​​the droplet DP. In other words, when the droplet DP deviates from the focus position, the correction unit 300 may correct the error generated between the area of ​​the first image IM1 and the actual area of ​​the droplet DP. In an embodiment, the area of ​​the first image IM1 may be corrected to the actual area of ​​the droplet DP based on the distance and direction in which the droplet DP deviates from the focus position.

[0068] The control part 400 may feedback control the focal position of the measuring part 200. In an embodiment, the focal position of the measuring part 200 may be feedback controlled based on the area of ​​the first image IM1 and the distance and direction in which the droplet DP deviates from the focal position.

[0069] In addition, the discharge amount of the droplet DP can be evaluated based on the actual area of ​​the droplet DP corrected by the correction part 300. That is, even if an error occurs in the measured area of ​​the droplet DP deviated from the focus position, it can be determined based on the actual area of ​​the droplet DP whether the droplet DP is uniformly discharged onto the target substrate SUB.

[0070] In the method S1000 for measuring a droplet according to an embodiment of the present disclosure, the area of ​​the droplet DP imaged by the measuring portion 200 can be corrected to the actual area of ​​the droplet DP based on the distance and direction in which the droplet DP deviates from the focal position of the measuring portion 200. Accordingly, even if the droplet DP deviates from the focal position of the measuring portion 200, the error between the imaged area of ​​the droplet DP and the actual area of ​​the droplet DP can be automatically corrected, so that the discharge amount of the droplet DP can be evaluated based on the actual area of ​​the droplet DP. Therefore, even if the upper surface of the target substrate SUB is uneven, the discharge amount of the droplet DP can be controlled to be uniform, so that the quality of the product including the droplet DP can be improved.

[0071] The present disclosure can be applied to the manufacturing process of various display devices. For example, the present disclosure can be applied to the manufacturing process of various display devices such as display devices for vehicles, ships and aircraft, portable communication devices, display devices for exhibitions or information transmission, and medical display devices.

[0072] The foregoing is an illustration of the embodiments and should not be construed as limiting them. Although the embodiments have been described, it will be readily appreciated by those skilled in the art that many modifications may be made in the embodiments without substantially departing from the novel teachings and advantages of the inventive concept. Accordingly, all such modifications are intended to be included within the scope of the inventive concept as defined in the claims. Therefore, it should be understood that the foregoing is an illustration of various embodiments and should not be construed as being limited to the specific embodiments disclosed, and modifications to the disclosed embodiments and other embodiments are intended to be included within the scope of the claims.

Claims

1. A method for measuring a droplet, the method comprising: expelling droplets onto a substrate; imaging the droplet using a measurement portion spaced apart from the droplet in one direction; measuring the distance between the liquid droplet and the measuring portion; as well as The droplet is corrected for its area.

2. The method according to claim 1, wherein: The measuring of the distance between the droplet and the measuring portion includes: The distance by which the droplet deviates from the focal position of the measuring section is measured.

3. The method according to claim 2, wherein: The measuring of the distance by which the droplet deviates from the focal position of the measuring section includes: A grayscale change of an edge portion of a first image of the liquid droplet imaged by the measuring portion is determined.

4. The method according to claim 3, wherein: In the determination of the grayscale change of the edge portion of the first image of the liquid droplet imaged by the measuring section, The grayscale change of the edge portion of the first image is compared with the grayscale change of the edge portion of a second image of the droplet imaged by the measuring section at the focal position.

5. The method according to claim 4, wherein: The measuring of the distance between the droplet and the measuring portion further comprises: A direction in which the droplet deviates from the focal position of the measurement section is measured.

6. The method according to claim 5, wherein: The measuring of the direction in which the droplet deviates from the focal position of the measuring section includes: The grayscale of the feature points of the first image of the droplet is determined.

7. The method according to claim 6, wherein: In the determination of the grayscale of the feature point of the first image of the droplet, The grayscale of the feature point of the first image is compared with the grayscale of the feature point of the second image.

8. The method according to claim 5, wherein: The measuring of the distance between the droplet and the measuring portion further comprises: The area of ​​the first image of the droplet is measured.

9. The method according to claim 8, wherein: In the measuring of the area of ​​the first image of the droplet, The area of ​​the first image is compared to the area of ​​the second image.

10. The method according to claim 5, wherein: In the correction of the area of ​​the droplet, The area of ​​the first image is corrected to an actual area of ​​the droplet based on the distance by which the droplet deviates from the focal position of the measuring section and the direction in which the droplet deviates from the focal position of the measuring section.

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