Apparatus for detecting liquid droplets and method for detecting liquid droplets using same

Abstract

Disclosed are an apparatus for detecting liquid droplets and a method for detecting liquid droplets using the same. The apparatus for detecting a droplet of a plurality of droplets includes: a detection substrate defining a penetration region corresponding to a nozzle portion discharging the plurality of droplets, at least some of the plurality of droplets discharged from the nozzle portion passing through the penetration region; and a camera that measures liquid droplets remaining on one surface of the detection substrate that do not pass through the detection substrate through the penetration region.

Description

Technical Field

[0001] The present disclosure generally relates to an apparatus for detecting liquid droplets. More specifically, the present disclosure relates to an apparatus for detecting liquid droplets and a method for detecting liquid droplets using the apparatus. Background Art

[0002] The printing apparatus including the inkjet head is used to form an alignment layer or apply ultraviolet (UV) ink on a substrate in a process of manufacturing a liquid crystal display device, or to apply ink on a substrate in a process of manufacturing an organic light emitting display device.

[0003] In a process using an inkjet head, a detection device may be used to detect the amount of liquid droplets discharged from each of a plurality of nozzles included in the inkjet head and whether liquid droplets are discharged. Summary of the invention

[0004] The embodiment provides a liquid droplet detection apparatus for detecting a liquid droplet discharge defect.

[0005] The embodiment provides a droplet detection method for detecting a droplet discharge defect.

[0006] In one embodiment of the present disclosure, an apparatus for detecting a droplet among a plurality of droplets includes: a detection substrate defining a penetration area corresponding to a nozzle portion that discharges the plurality of droplets, at least some of the plurality of droplets discharged from the nozzle portion passing through the penetration area; and a camera measuring droplets remaining on a surface of the detection substrate that do not pass through the detection substrate through the penetration area.

[0007] In one embodiment, the plurality of droplets discharged from the nozzle portion may include a main droplet and a satellite droplet. The volume of the satellite droplet may be smaller than the volume of the main droplet. The camera may measure the satellite droplet remaining on one surface of the detection substrate.

[0008] In one embodiment, the nozzle portion may include a plurality of nozzles arranged in a row along a first direction in a plan view, and the penetration region may define a plurality of penetration holes corresponding to the plurality of nozzles, respectively. A first interval between the plurality of penetration holes in the first direction may be an integer multiple of a second interval between the plurality of nozzles in the first direction.

[0009] In one embodiment, the plurality of penetration holes may correspond one-to-one to the plurality of nozzles.

[0010] In one embodiment, a maximum length of each of the plurality of penetration holes in the first direction may be smaller than a second interval between the plurality of nozzles in the first direction.

[0011] In one embodiment of the present disclosure, a method for detecting droplets among a plurality of droplets includes: preparing a detection substrate defining a penetration area through which at least some of a plurality of droplets discharged from a nozzle portion pass; aligning the detection substrate so that the penetration area corresponds to the nozzle portion; discharging a plurality of droplets from the nozzle portion; and measuring droplets remaining on a surface of the detection substrate that have not passed through the detection substrate through the penetration area.

[0012] In one embodiment, the plurality of droplets discharged from the nozzle portion may include a main droplet and a satellite droplet. The volume of the satellite droplet may be smaller than the volume of the main droplet. The main droplet may be discharged before the satellite droplet.

[0013] In one embodiment, the main droplet may pass through the detection substrate through the penetration area. A portion of the satellite droplet may remain on the one surface of the detection substrate without passing through the detection substrate. A portion of the satellite droplet may be measured in the step of measuring the droplet on the one surface of the detection substrate.

[0014] In an embodiment, the method may further include: after measuring the liquid droplet, changing a discharge condition of the nozzle part by evaluating information on the liquid droplet remaining on one surface of the inspection substrate.

[0015] In one embodiment, the nozzle portion may include a plurality of nozzles arranged in a row along the first direction in a plan view. The penetration region may define a plurality of penetration holes. In the step of aligning the detection substrate, the plurality of penetration holes may be aligned to correspond to the plurality of nozzles, respectively.

[0016] In one embodiment of the present disclosure, a droplet detection device may include: a detection substrate defining a plurality of penetration holes through which at least some of a plurality of droplets discharged from each of a plurality of nozzles pass; and a camera measuring droplets remaining on one surface of the detection substrate. In this case, the droplets remaining on one surface of the detection substrate may be satellite droplets that are not discharged to a target position.

[0017] By defining penetration holes through which at least some of the droplets pass through the detection substrate, each of the nozzles can discharge hundreds of thousands to millions of droplets while the position of the inkjet head is fixed. The camera can measure satellite droplets remaining on one surface of the detection substrate.

[0018] Therefore, the droplet detection apparatus can detect a discharge defect of a satellite droplet, wherein the frequency of occurrence of the discharge defect is relatively low. In other words, the droplet detection apparatus can simplify the process for detecting a discharge defect of a satellite droplet. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Illustrative, non-limiting embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.

[0020] Figure 1 is a perspective view illustrating an embodiment of a liquid droplet detection apparatus according to the present disclosure.

[0021] Figure 2 As an example Figure 1 Side view of a droplet detection device.

[0022] Figure 3 As an example Figure 1 A plan view of an embodiment of an inkjet head.

[0023] Figure 4 As an example Figure 1 A plan view of an embodiment of a substrate.

[0024] Figure 5 As an example Figure 1 A plan view of another embodiment of a substrate.

[0025] Figure 6 As an example Figure 1 A plan view of another embodiment of an inkjet head.

[0026] Figure 7 As an example Figure 1 A plan view of another embodiment of a substrate.

[0027] Figure 8 As an example Figure 1 A plan view of another embodiment of a substrate.

[0028] Fig. 9 The flowchart of one embodiment of the droplet detection method according to the present disclosure.

[0029] Fig.10 , Fig.11 , Fig.12 and Fig.13 For description Fig. 9 A perspective view of a droplet detection method. DETAILED DESCRIPTION

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

[0031] It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.

[0032] It will be understood that although the terms "first", "second", "third", etc. may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Therefore, the first element, component, region, layer or section discussed below may be referred to as a second element, component, region, layer or section without departing from the teachings herein.

[0033] The terms used in this article are only used for the purpose of describing specific embodiments and are not intended to be limiting. As used in this article, the singular forms "a", "an" and "the" are intended to include plural forms, including "at least one", unless the context clearly indicates otherwise. "Or" means "and / or". As used in this article, the term "and / or" includes any and all combinations of one or more related listed items. It will be further understood that the terms "comprises" and / or "comprising" or "includes" and / or "including", when used in this specification, indicate the presence of narrated features, regions, integers, steps, operations, elements, parts and / or groups thereof, but do not exclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, parts and / or groups thereof.

[0034] In addition, relative terms, such as "lower" or "bottom" and "upper" or "top", may be used herein to describe the relationship of one element to another element as illustrated in the figure. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figure. For example, if the device in one of the figures is turned over, the element described as being on the "lower" side of the other element will then be oriented on the "upper" side of the other element. Therefore, depending on the specific orientation in the figure, the exemplary term "lower" can encompass both "lower" and "upper" orientations. Similarly, if the device in one of the figures is turned over, the element described as being "below" or "below" the other element will then be oriented to be "above" the other element. Therefore, the exemplary term "below" or "below" can encompass both upper and lower orientations.

[0035] As used herein, "about" or "approximately" includes the recited value and means within an acceptable range of deviation of the particular value determined by one of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system). For example, a term such as "about" can mean within one or more standard deviations, or within ±30%, ±20%, ±10%, ±5% of the recited value.

[0036] Unless otherwise defined, all terms (including technical and scientific terms) used in this article have the same meaning as those commonly understood by ordinary technicians in the field to which the present disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant technical field and the present disclosure, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such in this article.

[0037] Figure 1 is a perspective view illustrating an embodiment of a liquid droplet detection apparatus according to the present disclosure. Figure 2 As an example Figure 1 Side view of a droplet detection device.

[0038] In this specification, a plane may be defined by a first direction DR1 and a second direction DR2 intersecting the first direction DR1. In one embodiment, for example, the first direction DR1 and the second direction DR2 may be perpendicular to each other. A direction orthogonal to the plane, that is, a thickness direction of the detection substrate SUB, may be a third direction DR3. In other words, the third direction DR3 may be perpendicular to each of the first direction DR1 and the second direction DR2.

[0039] See also Figure 1 and Figure 2 , a droplet detecting apparatus 100 in an embodiment of the present disclosure may include a detecting substrate SUB, a camera CAM, and a receiving portion CTA.

[0040] The liquid droplet detecting apparatus 100 in an embodiment of the present disclosure may be used to detect liquid droplets IK discharged from a nozzle portion included in an inkjet head HD.

[0041] The inkjet head HD may be included in a printing device for forming an alignment layer or applying ultraviolet (UV) ink on a substrate in a process of manufacturing a liquid crystal display device, or a printing device for applying ink on a substrate in a process of manufacturing an organic light-emitting display device, etc.

[0042] The inkjet head HD may include a nozzle portion capable of discharging the liquid droplets IK, and the nozzle portion may include a plurality of nozzles NZ. The nozzles NZ may be arranged in a row along the first direction DR1. Each of the nozzles NZ may discharge the liquid droplets IK.

[0043] The droplet IK may be a liquid containing various materials. In one embodiment, for example, the droplet IK may be an organic light-emitting ink for forming a pixel included in a display device. In this case, the organic light-emitting ink may be an ink mixed with an organic light-emitting material and a solvent. The organic light-emitting material may be a red organic light-emitting material, a green organic light-emitting material, or a blue organic light-emitting material. When a voltage is applied, the organic light-emitting material may emit light (e.g., red light, green light, or blue light). The solvent may be a material capable of dissolving the organic light-emitting material. The solvent may be a material that is easily miscible with the organic light-emitting material.

[0044] The droplet IK may include a main droplet MD and a satellite droplet SAT. The main droplet MD may be discharged before the satellite droplet SAT. In addition, the volume of the satellite droplet SAT may be smaller than the volume of the main droplet MD. The discharge amount and discharge frequency of the satellite droplet SAT may vary according to the physical properties of the droplet IK (e.g., viscosity, surface tension, etc.), the temperature of the nozzle NZ, the voltage applied to the inkjet head HD, and the distance between the nozzle NZ and the substrate.

[0045] like Figure 2 As illustrated in FIG. 1 , some of the satellite droplets SAT may not be discharged to the target position due to various reasons (e.g., generation of airflow, adsorption of foreign matter on the nozzle NZ). In other words, the satellite droplets SAT may include first satellite droplets SAT1 discharged to the target position in a direction opposite to the third direction DR3 and second satellite droplets SAT2 not discharged to the target position. In one embodiment, the droplet detection apparatus 100 may detect the second satellite droplet SAT2 not discharged to the target position among the droplets IK discharged from the nozzle NZ. In other words, the droplet detection apparatus 100 may detect a discharge defect of the satellite droplets SAT discharged from the nozzle NZ.

[0046] The detection substrate SUB may include a transparent or opaque material. In one embodiment, for example, the detection substrate SUB may include glass or plastic. In this case, the detection substrate SUB may include a quartz substrate, a synthetic quartz substrate, a calcium fluoride substrate, a fluorine-doped quartz substrate, soda-lime glass, an alkali-free glass substrate, a polyimide substrate, a polycarbonate substrate, etc. These substrates may be used alone or in any combination with each other.

[0047] The detection substrate SUB may define a penetration region through which at least some of the droplets IK discharged from the nozzle portion pass, the penetration region corresponding to the nozzle portion that discharges the droplets IK. In a cross section, the penetration region may be disposed on the same line as the nozzle portion. In addition, the penetration region may define a plurality of penetration holes TH. The penetration holes TH may correspond to the nozzles NZ, respectively. That is, in a cross section, the penetration holes TH may be disposed on the same line as the nozzles NZ, respectively. In other words, the penetration holes TH may be disposed on the same line extending in the third direction DR3 as the nozzles NZ, respectively. Therefore, at least some of the droplets IK discharged from each of the nozzles NZ may pass through the detection substrate SUB through the penetration holes TH.

[0048] In an embodiment, each of the through holes TH may have an elliptical planar shape. However, the present disclosure is not limited thereto, and each of the through holes TH may have one of various planar shapes. In an embodiment, for example, each of the through holes TH may have one of a triangular planar shape, a quadrilateral planar shape (e.g., a rectangular planar shape), a circular planar shape, etc.

[0049] Specifically, the droplet IK discharged to the target position from each of the nozzles NZ in the direction opposite to the third direction DR3 may pass through the detection substrate SUB through the penetration hole TH. In contrast, the droplet not discharged to the target position may not enter the penetration hole TH, in which case the droplet not discharged to the target position may be the second satellite droplet SAT2. In other words, the second satellite droplet SAT2 may fall on one surface of the detection substrate SUB without passing through the detection substrate SUB. Therefore, the second satellite droplet SAT2 may remain on one surface of the detection substrate SUB without passing through the detection substrate SUB.

[0050] In one embodiment, the detection substrate SUB may further include a liquid-repellent material. In one embodiment, for example, the liquid-repellent material may include a fluorine compound or a siloxane compound. The liquid-repellent material may be disposed on the surface of the detection substrate SUB. In other words, the liquid-repellent material may cover the surface of the detection substrate SUB. Therefore, the surface of the detection substrate SUB may have liquid-repellency.

[0051] Since the surface of the detection substrate SUB has liquid repellency, the contact angle between the surface of the detection substrate SUB and the second satellite droplet SAT2 remaining on one surface of the detection substrate SUB can be increased. In other words, the binding force between the surface of the detection substrate SUB and the second satellite droplet SAT2 and the surface tension of the second satellite droplet SAT2 remaining on one surface of the detection substrate SUB can be increased. Therefore, the camera CAM can measure the second satellite droplet SAT2 more accurately.

[0052] The camera CAM may be disposed above one surface of the detection substrate SUB. The camera CAM may measure droplets remaining on one surface of the detection substrate SUB that have not passed through the detection substrate SUB through the penetration area. Specifically, the camera CAM may measure second satellite droplets SAT2 remaining on one surface of the detection substrate SUB. In other words, the camera CAM may capture one surface of the detection substrate SUB and measure an image of the second satellite droplets SAT2 remaining on one surface of the detection substrate SUB. Therefore, the camera CAM may measure the size of the second satellite droplets SAT2 and the number of the second satellite droplets SAT2 remaining on one surface of the detection substrate SUB. In one embodiment, for example, the camera CAM may be a line scan camera or an area scan camera.

[0053] The receiving portion CTA may be disposed below the detection substrate SUB. The receiving portion CTA may accommodate the droplet IK that passes through the detection substrate SUB through the penetration region. Here, the droplet IK accommodated in the receiving portion CTA may include a main droplet MD and a first satellite droplet SAT1. In other words, the second satellite droplet SAT2 that is not discharged to the target position may not be accommodated in the receiving portion CTA.

[0054] The droplet detection device 100 in one embodiment of the present disclosure may include: a detection substrate SUB, defining a penetration hole TH through which at least some of the droplets IK discharged from each of the nozzles NZ pass; and a camera CAM, measuring second satellite droplets SAT2 remaining on one surface of the detection substrate SUB. By defining the penetration hole TH through which at least some of the droplets IK pass through the detection substrate SUB, each of the nozzles NZ can discharge hundreds of thousands to millions of droplets IK while the position of the inkjet head HD is fixed. After each of the nozzles NZ discharges a droplet IK, the camera CAM can measure the second satellite droplets SAT2 remaining on one surface of the detection substrate SUB that are not discharged to the target position. Therefore, the droplet detection device 100 can detect a discharge defect of a satellite droplet SAT, wherein the frequency of occurrence of the discharge defect is relatively low. In other words, the droplet detection device 100 can simplify the process for detecting a discharge defect of a satellite droplet SAT.

[0055] Figure 3 As an example Figure 1 A plan view of an embodiment of an inkjet head. Figure 4 As an example Figure 1 A plan view of an embodiment of a substrate. Figure 5 As an example Figure 1 A plan view of another embodiment of a substrate.

[0056] See also Figure 3 , Figure 4 and Figure 5, the inkjet head HD may include a nozzle portion, and the nozzle portion may include nozzles NZ. In a plan view, the nozzles NZ may be arranged in a row along a row direction. In other words, in a plan view, the nozzles NZ may be arranged in a row along a first direction DR1. In this case, the interval between the nozzles NZ in the first direction DR1 may be defined as a second interval IN2. In one embodiment, for example, the number of nozzles NZ repeatedly arranged in a row may be about 128 or about 256. However, the number of nozzles NZ is not limited thereto.

[0057] In addition, in a plan view, the nozzles NZ may be arranged in a row along a column direction. In other words, in a plan view, the nozzles NZ may be arranged in a row along the second direction DR2. That is, the nozzles NZ may include a plurality of groups arranged in a row along the first direction DR1 in a plan view, and the plurality of groups may be arranged along the second direction DR2.

[0058] The penetration area may be defined in the detection substrate SUB, and the penetration area may define a penetration hole TH. The penetration holes TH may correspond to the nozzles NZ, respectively. In other words, in a cross section, the penetration holes TH may be respectively arranged on the same line as the nozzles NZ. In a plan view, the penetration holes TH may be arranged in a row along the direction of the row. In other words, in a plan view, the penetration holes TH may be arranged in a row along the first direction DR1. In an embodiment, the interval between the penetration holes TH in the first direction DR1 may be defined as a first interval IN1, and the first interval IN1 may be equal to the second interval IN2.

[0059] In addition, the through holes TH may be arranged in a row along the column direction in a plan view. In other words, the through holes TH may be arranged in a row along the second direction DR2 in a plan view. That is, the through holes TH may include a plurality of groups arranged in a row along the first direction DR1 in a plan view, and the plurality of groups may be arranged along the second direction DR2.

[0060] In one embodiment, the maximum length LD of each of the penetration holes TH in the first direction DR1 may be smaller than the interval between the nozzles NZ in the first direction DR1. In other words, the maximum length LD of each of the penetration holes TH in the first direction DR1 may be smaller than the second interval IN2. In one embodiment, for example, each of the penetration holes TH may have an elliptical planar shape. In this case, the maximum length LD of each of the penetration holes TH in the first direction DR1 may be defined as the length of the major axis of the ellipse. When the maximum length LD of each of the penetration holes TH in the first direction DR1 exceeds the second interval IN2, the penetration holes TH adjacent to each other in the first direction DR1 may overlap each other in a plan view. In this case, the size of the second satellite droplets and the number of the second satellite droplets may be inaccurately measured.

[0061] In one embodiment, if Figure 4 As illustrated in FIG. 1 , the through holes TH may be defined in the detection substrate SUB to correspond one-to-one with the nozzles NZ. In other words, the number of the through holes TH defined in the detection substrate SUB may be equal to the number of the nozzles NZ included in the inkjet head HD.

[0062] In another embodiment, if Figure 5 As illustrated in , the number of penetration holes TH defined in the detection substrate SUB may be greater than the number of nozzles NZ included in the inkjet head HD. In this case, the number of penetration holes TH repeatedly arranged in a row and the number of nozzles NZ repeatedly arranged in a row may be equal, and the number of penetration holes TH repeatedly arranged in a column may be greater than the number of nozzles NZ repeatedly arranged in a column. In this case, the nozzle portion may be moved along the second direction DR2. Specifically, the inkjet head HD may be moved along the second direction DR2. In other words, the inkjet head HD may be moved along the direction of the column.

[0063] Figure 6 As an example Figure 1 A plan view of another embodiment of an inkjet head. Figure 7 As an example Figure 1 A plan view of another embodiment of a substrate. Figure 8 As an example Figure 1 A plan view of another embodiment of a substrate.

[0064] See also Figure 6 , Figure 7 and Figure 8 , the inkjet head HD' may include a nozzle portion, and the nozzle portion may include nozzles NZ'. In a plan view, the nozzles NZ' may be arranged in a row along a row direction. In other words, in a plan view, the nozzles NZ' may be arranged in a row along a first direction DR1. In this case, the interval between the nozzles NZ' in the first direction DR1 may be defined as a second interval IN2. In one embodiment, for example, the number of nozzles NZ' repeatedly arranged in a row may be about 128 or about 256. However, the number of nozzles NZ' is not limited thereto.

[0065] Furthermore, in a plan view, the nozzles NZ' may be repeatedly arranged along the direction of the column. In other words, in a plan view, the nozzles NZ' may be repeatedly arranged along the second direction DR2. In an embodiment, in a plan view, for example, the nozzles NZ' may be arranged in a zigzag shape.

[0066] A penetration area is defined in the detection substrate SUB', and the penetration area may define a penetration hole TH'. The penetration holes TH' may correspond to the nozzles NZ', respectively. In other words, in a cross section, the penetration holes TH' may be disposed on the same line as the nozzles NZ'. In a plan view, the penetration holes TH' may be arranged in a row along a row direction. In other words, in a plan view, the penetration holes TH' may be arranged in a row along a first direction DR1. The interval between the penetration holes TH' in the first direction DR1 may be defined as a first interval IN1.

[0067] In addition, in a plan view, the through holes TH' may be repeatedly arranged along the column direction. In other words, in a plan view, the through holes TH' may be repeatedly arranged along the second direction DR2. In an embodiment, in a plan view, for example, the through holes TH' may be arranged in a zigzag shape.

[0068] In one embodiment, the interval between the through holes TH' in the first direction DR1 may be an integer multiple of the interval between the nozzles NZ' in the first direction DR1. In other words, the first interval IN1 may be an integer multiple of the second interval IN2.

[0069] In one embodiment, if Figure 7 As illustrated in FIG. 1 , for example, the first interval IN1 may be one time the second interval IN2. In other words, the second interval IN2 may be equal to the first interval IN1.

[0070] In another embodiment, if Figure 8 As illustrated in FIG. 1 , the first interval IN1′ may be twice the second interval IN2. In this case, the droplet detection apparatus 100 may detect the satellite droplet discharge defects of the nozzles arranged in odd columns among the nozzles NZ′ repeatedly arranged in a row. In an alternative embodiment, the droplet detection apparatus 100 may detect the satellite droplet discharge defects of the nozzles arranged in even columns among the nozzles NZ′ repeatedly arranged in a row.

[0071] Fig. 9 The flowchart of one embodiment of the droplet detection method according to the present disclosure. Fig.10 , Fig.11 , Fig.12 and Fig.13 For description Fig. 9 A perspective view of a droplet detection method.

[0072] See also Fig. 9In one embodiment of the present disclosure, a droplet detection method IM may include: preparing a detection substrate defining a penetration area (S100), aligning the detection substrate so that the penetration area corresponds to a nozzle portion of an inkjet head (S200), discharging droplets from the nozzle portion (S300), measuring droplets remaining on a surface of the detection substrate without passing through the penetration area through the detection substrate (S400), and changing a discharge condition of the nozzle portion by evaluating information about the droplets remaining on a surface of the detection substrate (S500).

[0073] See also Fig.10 , a detection substrate SUB defining a penetration area may be prepared ( S100 ).

[0074] The detection substrate SUB may define a penetration region through which the droplets may pass, and the penetration region may define a plurality of penetration holes TH. In one embodiment, for example, the detection substrate SUB may define six penetration holes TH. Three penetration holes TH may be arranged in a row in each of the first row and the second row along the first direction DR1. However, the present disclosure is not limited thereto.

[0075] The receiving portion CTA may be disposed below the detection substrate SUB. The receiving portion CTA may receive a droplet that passes through the detection substrate SUB through the penetration region.

[0076] See also Fig.11 , the inspection substrate SUB may be aligned so that the nozzle portion of the inkjet head HD corresponds to the penetration area (S200).

[0077] The inkjet head HD may include a nozzle portion capable of discharging droplets, and the nozzle portion may include a plurality of nozzles NZ. In one embodiment, for example, the inkjet head HD may include three nozzles NZ, and the three nozzles NZ may be arranged in a row along the first direction DR1. However, the present disclosure is not limited thereto.

[0078] The detection substrate SUB may be aligned so that the penetration holes TH respectively correspond to the nozzles NZ. In one embodiment, in a cross section, for example, three nozzles NZ respectively arranged in a row in a first row along the first direction DR1 may be disposed on the same line as three penetration holes TH respectively arranged in a row in a first row along the first direction DR1.

[0079] See also Fig.12 , the droplet IK may be discharged from the nozzle portion (S300).

[0080] Each of the nozzles NZ included in the inkjet head HD may discharge a droplet IK. The droplet IK may include a main droplet MD and a satellite droplet SAT. The main droplet MD may be discharged before the satellite droplet SAT. In addition, the volume of the satellite droplet SAT may be smaller than the volume of the main droplet MD. The satellite droplet SAT may include a first satellite droplet SAT1 discharged to a target position in a direction opposite to the third direction DR3 and a second satellite droplet SAT2 not discharged to the target position.

[0081] The main droplet MD and the first satellite droplet SAT1 may pass through the detection substrate SUB through the penetration hole TH. After passing through the detection substrate SUB, the main droplet MD and the first satellite droplet SAT1 may be accommodated in the receiving portion CTA.

[0082] The second satellite droplet SAT2 may not enter the penetration hole TH. In other words, the second satellite droplet SAT2 may fall on one surface of the detection substrate SUB without passing through the detection substrate SUB. Therefore, the second satellite droplet SAT2 may remain on one surface of the detection substrate SUB without passing through the detection substrate SUB.

[0083] In one embodiment, for example, while the position of the inkjet head HD is fixed, each of the nozzles NZ may discharge hundreds of thousands to millions of droplets IK. The droplet detection method IM in one embodiment of the present disclosure may include discharging hundreds of thousands to millions of droplets IK from each of the nozzles NZ to detect a discharge defect of a satellite droplet SAT, wherein the occurrence frequency of the discharge defect is relatively low.

[0084] With the position of the inkjet head HD fixed, after each of the nozzles NZ discharges hundreds of thousands to millions of droplets IK, the nozzle portion may be moved in a direction opposite to the second direction DR2. Specifically, the inkjet head HD may be moved in a direction opposite to the second direction DR2. Therefore, in a cross section, three nozzles NZ may be aligned so as to be arranged on the same line as three penetration holes TH arranged in a row in a second row along the first direction DR1. After aligning the nozzles NZ to correspond to the penetration holes TH arranged in the second row, each of the nozzles NZ may again discharge hundreds of thousands to millions of droplets IK while the position of the inkjet head HD is fixed. In an alternative embodiment, the process in which the inkjet head HD moves in a direction opposite to the second direction DR2 and each of the nozzles NZ again discharges droplets IK may be omitted.

[0085] See also Fig.13 , the droplet IK remaining on one surface of the detection substrate SUB may be measured (S400). Specifically, the second satellite droplet SAT2 remaining on one surface of the detection substrate SUB may be measured.

[0086] The camera CAM may be disposed above one surface of the detection substrate SUB. Therefore, the camera CAM may measure the second satellite droplets SAT2 remaining on one surface of the detection substrate SUB. In other words, the camera CAM may capture one surface of the detection substrate SUB and measure an image of the second satellite droplets SAT2 remaining on one surface of the detection substrate SUB. Based on the image of the second satellite droplets SAT2, the camera CAM may measure the size of the second satellite droplets SAT2 and the number of the second satellite droplets SAT2 on one surface of the detection substrate SUB.

[0087] The discharge condition of the nozzle part may be changed by evaluating information about the second satellite droplet SAT2 left on one surface of the inspection substrate SUB (S500). Specifically, the discharge condition of the inkjet head HD may be changed by evaluating information about the second satellite droplet SAT2.

[0088] The information about the second satellite droplets SAT2 measured by the camera CAM can be evaluated. That is, the size and number of the second satellite droplets SAT2 can be evaluated by comparing with the discharge amount of the droplets IK discharged from each of the nozzles NZ, in other words, the size and number of the second satellite droplets SAT2 can be evaluated by comparing with the number of the droplets IK discharged from each of the nozzles NZ, and therefore, the discharge defects of the satellite droplets SAT discharged from the nozzles NZ can be detected.

[0089] When the information about the second satellite droplet SAT2 is evaluated and exceeds the emission defect standard value, the emission condition of the inkjet head HD may be changed. In one embodiment, for example, the emission condition of the inkjet head HD may include the temperature of the nozzle NZ, the voltage applied to the inkjet head HD, and the distance between the nozzle NZ and the detection substrate SUB. In an alternative embodiment, for example, when the information about the second satellite droplet SAT2 exceeds the emission defect standard value, the physical properties of the droplet IK provided may be changed. In one embodiment, for example, the physical properties of the droplet IK may include viscosity, surface tension, etc.

[0090] The present disclosure may be applied to various display devices. In one embodiment, the present disclosure may be applied to various display devices, such as display devices for vehicles, ships and aircraft, display devices for portable communication devices, display devices for exhibitions or information transmission, or medical display devices, etc.

[0091] The foregoing is an illustration of the embodiments of the present disclosure and should not be construed as limiting thereof. Although several embodiments have been described with reference to the accompanying drawings, it will be readily appreciated by those skilled in the art that many variations and modifications may be made therein without departing from the spirit and scope of the present disclosure as defined in the appended claims.

Claims

1. A device for detecting a droplet among a plurality of droplets, the device comprising: a detection substrate defining a penetration area corresponding to a nozzle portion that discharges the plurality of liquid droplets, at least some of the plurality of liquid droplets discharged from the nozzle portion passing through the penetration area; and A camera measures the droplets remaining on one surface of the detection substrate without passing through the detection substrate through the penetration area.

2. The apparatus according to claim 1, wherein the plurality of droplets discharged from the nozzle portion include main droplets and satellite droplets, The volume of the satellite droplet is smaller than the volume of the main droplet, and The camera measures the satellite droplets remaining on the one surface of the detection substrate.

3. The apparatus according to claim 1, wherein the nozzle portion comprises a plurality of nozzles arranged in a row along a first direction in a plan view, The penetration area defines a plurality of penetration holes corresponding to the plurality of nozzles, respectively, and A first interval between the plurality of penetration holes in the first direction is an integer multiple of a second interval between the plurality of nozzles in the first direction. 4 . The apparatus according to claim 3 , wherein the plurality of penetration holes correspond one-to-one to the plurality of nozzles. 5 . The apparatus according to claim 3 , wherein a maximum length of each of the plurality of penetration holes in the first direction is smaller than the second interval between the plurality of nozzles in the first direction.

6. A method for detecting a droplet among a plurality of droplets, the method comprising: preparing a detection substrate defining a penetration region through which at least some of the plurality of liquid droplets discharged from the nozzle portion pass; aligning the detection substrate so that the penetration area corresponds to the nozzle portion; discharging the plurality of droplets from the nozzle portion; as well as The droplet remaining on one surface of the detection substrate without passing through the detection substrate through the penetration region is measured.

7. The method of claim 6, wherein the plurality of droplets discharged from the nozzle portion include main droplets and satellite droplets, The volume of the satellite droplet is smaller than the volume of the main droplet, and The main droplet is discharged before the satellite droplet.

8. The method according to claim 7, wherein the main droplet passes through the detection substrate through the penetration area, A portion of the satellite droplets remains on the one surface of the detection substrate without passing through the detection substrate, and The portion of the satellite droplets is measured in the step of measuring the droplets on the one surface of the detection substrate.

9. The method according to claim 6, further comprising: After the measuring of the liquid droplet, a discharge condition of the nozzle portion is changed by evaluating information on the liquid droplet remaining on the one surface of the detection substrate.

10. The method according to claim 6, wherein the nozzle portion comprises a plurality of nozzles arranged in a row along a first direction in a plan view, The penetration region defines a plurality of penetration holes, and In the step of aligning the inspection substrate, the plurality of penetration holes are aligned to correspond to the plurality of nozzles, respectively.

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