System for determining corrugation of conveyed film

Abstract

The present disclosure relates to a system for determining corrugation of a film, which has a predetermined dimension in a width direction and extends in a longitudinal direction, due to tension acting on the film and inhomogeneity of a film material in a roll-to-roll inline apparatus that conveys the film in the longitudinal direction. The system includes: a lateral displacement sensor mounted on one or more of two sides of the film in a width direction to be spaced apart from a surface of the film, and configured to measure a displacement of the surface of the film; and a ripple determination unit for converting a lateral displacement value of the film surface as a function of time measured by the lateral displacement sensor into an amplitude value as a function of the frequency signal and comparing the converted amplitude value with a preset amplitude value as a function of the frequency signal, to determine the presence or absence of corrugations in the membrane.

Description

Technical Field

[0001] This disclosure claims the benefit of Korean Patent Application No. 10-2024-0024376, filed with the Korean Intellectual Property Office on February 20, 2024, the entire contents of which are incorporated herein by reference.

[0002] This disclosure relates to a system for determining the waviness of a film, and more specifically, to a system for converting data measured in real time by a displacement sensor to determine the waviness of a separator produced in a roll-to-roll apparatus and the good / defective quality of the resulting separator. Background Technology

[0003] The separator is a conductive membrane that isolates the two electrode portions of a secondary battery to prevent them from physically contacting each other and provides channels for ion movement through micropores. The separator can be individually processed by a roller-to-roll device using multiple rollers to improve processing speed.

[0004] In roll-to-roll processing, tension is applied to the separator by the rotation of the two rollers to rotate it onto the other roller. However, during the drying process of Safety Reinforced Separator (SRS) coating, the coating should be formed so that it does not contact the rollers before drying, and therefore, the distance between the rollers is formed to be very wide. Due to the distance between the rollers and the weak tension applied to the separator, corrugations are generated in the separator, and when the width of the corrugations formed in the separator is large, the separator may be damaged due to contact with the upper and lower parts of the drying equipment.

[0005] Therefore, in order to predict whether the separator will be damaged due to corrugation, Incoming Quality Control (IQC) is performed to check for any abnormalities in the membrane.

[0006] However, in existing IQC (Independent Quality Control), some samples are collected and inspected before processing. Therefore, the representativeness of the samples may be questionable, and because samples are inspected individually, it is costly and time-consuming, and there is a risk of damaging objects during sample extraction. In particular, because sample extraction and measurement are separate from processing and performed manually, the accuracy of the data obtained as inspection results may also be problematic.

[0007] In summary, the existing inspection method IQC not only cannot identify defective products in real time, but also has many drawbacks in terms of cost, time and accuracy.

[0008] The above background technology refers to technical information that the inventor possesses or acquires during the processing of the embodiments of this disclosure, but it is not necessarily publicly known technology disclosed to the general public before the embodiments of this disclosure were submitted. Summary of the Invention

[0009] Technical issues

[0010] To address the above issues, this disclosure provides a thin film ripple determination system for determining the generation of ripples and good / defective quality of a thin film by: mounting a displacement sensor spaced apart from the surface of a separator in a roll-to-roll apparatus; converting the measured displacement value of the separator into an amplitude value based on a frequency signal; and comparing it with a preset amplitude value.

[0011] Technical solutions

[0012] The film ripple determination system according to embodiments of this disclosure is a system for determining film ripples in a roll-to-roll inline apparatus for conveying a film in the longitudinal direction due to tension acting on the film and non-uniformity of the film material. The film is formed having a predetermined dimension in the width direction and extending in the longitudinal direction. The system includes: a lateral displacement sensor mounted on one or more sides of the film in the width direction, spaced apart from the surface of the film, and configured to measure the displacement of the film surface; and a ripple determination unit for converting the time-dependent lateral displacement value of the film surface measured by the lateral displacement sensor into an amplitude value based on a frequency signal, and comparing the converted amplitude value with a preset amplitude value based on the frequency signal to determine the presence or absence of ripples in the film.

[0013] According to embodiments of this disclosure, a lateral displacement sensor can measure the displacement of the thin film surface by irradiating light perpendicularly toward the surface of the thin film.

[0014] According to embodiments of this disclosure, the displacement of the thin film surface can be measured by the angle and wavelength of light irradiated from a lateral displacement sensor and reflected from the thin film surface.

[0015] According to embodiments of this disclosure, the lateral displacement sensor may be a laser sensor.

[0016] According to embodiments of this disclosure, the ripple determination unit can determine that the film is defective when the converted amplitude value falls outside a predetermined range based on a preset amplitude value.

[0017] According to embodiments of this disclosure, the system may further include a center displacement sensor mounted at the center of the film in the width direction, spaced apart from the film surface, and configured to measure the displacement of the film surface.

[0018] According to embodiments of this disclosure, the system may further include a calibration unit for correcting the lateral displacement value of the film measured by the lateral displacement sensor based on the center displacement value of the film measured by the center displacement sensor.

[0019] According to embodiments of this disclosure, the calibration unit can correct the lateral displacement value by subtracting the center displacement value of the film measured by the center displacement sensor from the lateral displacement value of the film measured by the lateral displacement sensor.

[0020] According to embodiments of this disclosure, the calibration unit can correct the lateral displacement value by dividing the lateral displacement value of the film measured by the lateral displacement sensor by the center displacement value of the film measured by the center displacement sensor.

[0021] According to embodiments of this disclosure, the corrugation determination unit can determine the lateral displacement value of the thin film based on values ​​measured at predetermined time intervals.

[0022] According to embodiments of this disclosure, the corrugation determination unit can identify portions of the film that have been determined to be defective by measuring the lateral displacement values ​​of the film at predetermined time intervals.

[0023] According to embodiments of this disclosure, the ripple determination unit can determine whether the thin film has defects in a frequency range of 15 Hz or greater and 30 Hz or less.

[0024] According to embodiments of this disclosure, the ripple determination unit can determine whether the thin film has defects in a frequency range greater than 0 Hz and 2 Hz or less.

[0025] According to embodiments of this disclosure, the corrugation determination unit can calculate a preset amplitude value based on at least one of the following parameters: the distance between the rollers of the roller-to-roll online equipment, the position of the lateral displacement sensor, the thickness, weight, and distance in the width direction of the film, the tension acting on the film, and the film conveying speed.

[0026] According to embodiments of this disclosure, the ripple determination unit may use a fast Fourier transform when converting the measured time-dependent lateral displacement value of the thin film into a converted amplitude value based on a frequency signal.

[0027] According to embodiments of this disclosure, a lateral displacement sensor may be configured to be spaced from the end of the film by more than 0 cm and 5 cm or less in the width direction of the film.

[0028] According to embodiments of this disclosure, the system may further include a display unit for outputting the converted amplitude value in real time.

[0029] Beneficial effects

[0030] This disclosure automatically checks for ripples in the separator, thereby reducing costs and time.

[0031] Furthermore, unlike existing methods that extract samples, potentially damage objects, and inspect only a portion of the object, this disclosure performs a complete inspection of the separator, thereby increasing throughput.

[0032] In addition, this disclosure makes it easier to identify defective parts of the separator using data measured in real time.

[0033] In addition, since the settings are calculated based on various variables generated during processing, it is easier to find the cause of the ripples.

[0034] Furthermore, since it is easy to grasp the trend of the corrugations according to the processing method or batch (bundle unit) by quantifying the corrugations of the separators, the following effect exists: defects are removed in advance during the processing steps.

[0035] The effects that can be obtained from this disclosure are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art based on the following description. Attached Figure Description

[0036] Figure 1a and Figure 1b A photograph of a thin film corrugation determination system 1 according to an embodiment of the present disclosure is shown.

[0037] Figure 2 A block diagram of a thin film corrugation determination system 1 according to an embodiment of the present disclosure is shown.

[0038] Figure 3 A graph showing displacement values ​​measured by a displacement sensor in a thin-film corrugation determination system according to an embodiment of the present disclosure is illustrated.

[0039] Figure 4 A graph showing the amplitude values ​​of a frequency signal obtained by fast Fourier transform in a thin-film ripple determination system according to an embodiment of the present disclosure is illustrated.

[0040] Figure 5A graph showing the amplitude values ​​of a frequency signal for each predetermined segment in a thin-film corrugation determination system according to an embodiment of the present disclosure is illustrated.

[0041] Figure 6 A graph is shown illustrating the frequency range used to determine the good / defective quality of a thin film in a thin film corrugation determination system according to an embodiment of the present disclosure.

[0042] Figure 7 A graph showing the relationship between signal processing and ripple size in a thin film ripple determination system according to an embodiment of the present disclosure for determining the good / defective quality of a thin film.

[0043] Description of reference numerals and symbols in the attached figures

[0044] 1: Thin Film Ripple Determination System

[0045] 10: Lateral displacement sensor

[0046] 20: Center displacement sensor

[0047] 30: Calibration Unit

[0048] 40: Ripple Determination Unit

[0049] 50: Roller

[0050] 60: Display Unit

[0051] TF: Thin Film Detailed Implementation

[0052] This disclosure will become clear from the following detailed description of embodiments taken in conjunction with the accompanying drawings. However, this disclosure is not limited to the embodiments described below and can be implemented in various different forms. These embodiments are provided only to complete the disclosure and to fully inform those skilled in the art of its scope. This disclosure is defined only by the scope of the claims. Furthermore, the terminology used in this specification is for describing embodiments and is not intended to limit the disclosure.

[0053] Throughout this instruction manual, the singular form also includes the plural form, unless the context clearly states otherwise.

[0054] As used throughout the specification, the terms “comprising” and / or “including” mean that the presence or addition of one or more other components, steps, operations and / or devices besides those mentioned are not excluded, and may include other components rather than exclude them, unless expressly stated to the contrary.

[0055] Additionally, the term "...component / unit" as described throughout the specification refers to a unit that performs at least one function or operation, which may be implemented as hardware, software, or a combination of hardware and software.

[0056] Furthermore, throughout the specification, when a component is described as being “connected” to another component, this includes not only cases where they are “directly connected”, but also cases where they are “indirectly connected” through another component inserted between them.

[0057] The contents of this disclosure will be described in more detail below.

[0058] This disclosure relates to a system for determining the corrugation of a film, the system being used to automatically determine whether the film is damaged due to corrugation generated in a roll-to-roll apparatus that operates to rotate a film wound on one roll and wind it onto another roll. The film is a membrane having a predetermined width and length and can extend in a longitudinal direction and be wound on multiple rolls. The multiple rolls can rotate in the same direction to transport the film from one roll to another.

[0059] Because the film conveyed by the roller-to-roll equipment is rotated and transported while being wound around both ends, a certain amount of ripples may occur due to the tension acting on the film and the characteristics of the film material. When the ripples generated in the film are less than or equal to a predetermined level, there is no problem; however, when they exceed the predetermined range, the film may be damaged.

[0060] Here, "film" refers to a film conveyed by a roller-to-roll device, and there is no particular limitation, but in an embodiment, it can be a "separator". A separator is a conductive membrane that isolates the two electrode portions of a secondary battery to prevent the electrode portions from physically contacting each other, and provides channels for ion movement through micropores.

[0061] The present disclosure will be described in more detail below with respect to a system 1 for determining whether ripples are generated in an online roller-to-roll equipment for conveying separators.

[0062] Figure 1a and Figure 1b A photograph of a thin-film corrugation determination system 1 according to an embodiment of the present disclosure is shown, and... Figure 2 A block diagram of a thin film corrugation determination system 1 according to an embodiment of the present disclosure is shown.

[0063] Reference Figure 1a , Figure 1b and Figure 2 The thin film corrugation determination system 1 according to the embodiments of the present disclosure may include a lateral displacement sensor 10 and a corrugation determination unit 40.

[0064] The lateral displacement sensor 10 is a sensor for measuring the displacement of the thin film (TF) and can be mounted parallel to the width direction of the thin film (TF). Specifically, refer to... Figure 1a and Figure 1b The lateral displacement sensor 10 is formed above the lateral surface of the thin film (TF) in the width direction and can determine whether ripples are generated at the lateral ends of the thin film (TF).

[0065] The lateral displacement sensor 10 can be mounted on one or more sides of the thin film (TF) in the width direction. That is, referring to... Figure 1b Based on the conveying direction of the film (TF), the lateral displacement sensor 10 can be mounted above the right or left surface of the film (TF), or above both the right and left surfaces. Since the ripples generated in the film (TF) may occur independently, regardless of whether they are on the right or left side, the location of the ripples in the film (TF) conveyed by the roller-to-roll online equipment can be determined more accurately based on the number of lateral displacement sensors 10 installed.

[0066] Additionally, a lateral displacement sensor 10 can be positioned between the rollers 50 in a roll-to-roll inline device to measure the waviness of the film (TF). That is, Figure 1b As shown Figure 1a The front view of the lateral displacement sensor 10 disposed between the rollers 50, rather than the lateral displacement sensor 10 formed above the thin film (TF) formed on the upper side of the rollers 50.

[0067] The lateral displacement sensor 10 can be configured to be spaced apart from the thin film (TF) surface by a predetermined distance, which can be adjusted differently depending on the degree of ripple generation and the type of sensor.

[0068] Reference Figure 1b A lateral displacement sensor 10 is positioned above the surface of the film (TF) and can measure the distance from the surface of the film (TF). Unlike rigid bodies such as metals, the presence or absence and degree of ripples in the film (TF) depends not only on the properties of the film (TF) itself but also on the tension of the two rollers 50 that transport the film. Therefore, in the case of the film (TF), the presence or absence of ripples in the film (TF) can be determined by measuring the degree of ripples occurring on both sides (right and / or left) of the film.

[0069] Specifically, the lateral displacement sensor 10 can illuminate light (L) perpendicularly toward the surface of the thin film (TF). The illuminated light (L) can be reflected from the surface of the thin film (TF) and then received by the lateral displacement sensor 10. Therefore, the displacement of the surface of the thin film (TF) can be measured based on the angle and wavelength of the illuminated and reflected light (L).

[0070] In one embodiment, the lateral displacement sensor 10 may be a laser sensor used to measure the distance to the surface of the thin film (TF). The laser sensor is a sensor that uses a laser (L) to measure the distance to a target object, and can measure the displacement of the thin film (TF) surface based on the time change according to the travel distance of the laser (L) by receiving the laser (L) irradiated from the lateral displacement sensor 10 and reflected from the surface of the thin film (TF).

[0071] Furthermore, the lateral displacement sensor 10 can be configured to be spaced a predetermined distance from the end of the thin film (TF) in the width direction of the thin film (TF). Specifically, in this disclosure, when the thin film (TF) is a separator, the lateral displacement sensor 10 can be formed within a range greater than 0 cm and 5 cm or less from the end of the thin film (TF). Within this range, the extent of damage caused by corrugations formed in the separator can be more easily determined.

[0072] In addition to the lateral displacement sensor 10, the thin film ripple determination system 1 according to the embodiments of the present disclosure may also include a center displacement sensor 20 for measuring the displacement formed at the center of the thin film (TF) surface.

[0073] The center displacement sensor 20 can be mounted at the center of the thin film (TF) in the width direction and spaced a predetermined distance from the surface of the thin film (TF). The displacement value at the center of the thin film (TF) in the width direction, measured by the center displacement sensor 20, can itself determine the presence or absence of ripples in the thin film (TF), and can also be used to correct the displacement value of the thin film (TF) measured by the lateral displacement sensor 10. More specifically, the displacement value of the thin film (TF) measured by the center displacement sensor 20 can be used to calibrate the displacement value of the thin film (TF) measured by the lateral displacement sensor 10 to more accurately determine the presence or absence of ripples in the thin film (TF).

[0074] Therefore, this disclosure may also include a calibration unit 30 for performing the correction process. The calibration unit 30 can correct the displacement value of the thin film (TF) in various ways. In an embodiment, the calibration unit 30 may perform the correction by subtracting the center displacement value of the thin film (TF) measured by the center displacement sensor from the lateral displacement value of the thin film (TF) measured by the lateral displacement sensor 10, or by dividing the lateral displacement value of the thin film (TF) measured by the lateral displacement sensor 10 by the center displacement value of the thin film (TF) measured by the center displacement sensor.

[0075] In this case, the presence or absence of ripples formed in the film (TF) can be more easily determined by the dimensional difference or ratio between the displacement of the central portion and the displacement of the lateral portions. In other words, since the rollers 50 that transport the film (TF) are rigid bodies, it is usually difficult to distinguish whether the ripples generated in the film (TF) transported between the rollers 50 are caused by mechanical vibrations generated in the rollers 50 or by ripples generated in the film (TF) itself. Therefore, by measuring the displacement of the central portion separately, the mechanical vibrations generated in the rollers 50 can be detected, and the displacement of the lateral portions can be calibrated to more clearly determine the presence or absence of ripples formed in the film (TF).

[0076] The thin film ripple determination system 1 according to an embodiment of the present disclosure may further include a ripple determination unit 40, which is capable of determining ripples generated in the thin film (TF) using data measured from the lateral displacement sensor 10.

[0077] The ripple determination unit 40 can determine the presence or absence of ripples by converting the displacement value of the film (TF) surface measured by the lateral displacement sensor 10 into an amplitude value. That is, the lateral displacement sensor 10 can measure the lateral displacement value of the film (TF) surface as the film (TF) is being transported, and can obtain the lateral displacement value of the film (TF) surface over time. This displacement value of the film (TF) surface over time can be converted into an amplitude value based on a frequency signal, and this value can be compared with a preset amplitude value to determine the presence or absence of ripples in the film (TF). In summary, when the converted amplitude value does not fall outside a predetermined range based on the preset amplitude value within a specific frequency signal range, the film can be determined as a good product, and when the converted amplitude value falls outside the predetermined range, the film can be determined as a defective product.

[0078] Additionally, the converted amplitude value obtained by the ripple determination unit 40 can be directly output. More specifically, a display unit 60 may also be included, which outputs the converted amplitude value so that the operator can check the degree of ripple in real time. The display unit 60 is a visual device that outputs the ripple amplitude value in a digital or other format, and in some embodiments, it may be an LCD, but is not limited to any particular embodiment.

[0079] Ultimately, since the converted amplitude value of the ripples formed in the thin film (TF) can be calculated separately by the display unit 60, the degree of ripples formed in the thin film (TF) can be provided to the operator in real time.

[0080] The calibration unit 30 and the ripple determination unit 40 are microprocessors and may include a calculation unit, a control unit, etc. They are configured to calculate desired data based on input data through set computational processing, and can use general-purpose chip-type processing devices used in devices such as computers.

[0081] The determination of the presence or absence of ripples in the thin film (TF) by the ripple determination unit 40 will be described in more detail below.

[0082] When converting the measured time-dependent lateral displacement values ​​of the thin film (TF) into converted amplitude values ​​based on a frequency signal, a Fast Fourier Transform (FFT) can be used. The Fast Fourier Transform is a method that provides frequency information about a signal by converting the measured signal into individual spectral components. In this disclosure, as the thin film (TF) is conveyed along a roll-to-roll assembly, the lateral displacement values ​​of the thin film (TF) are sampled over a predetermined time period, the lateral displacement values ​​are divided into frequency components, and then represented as individual frequencies, each with its own amplitude and phase.

[0083] Ultimately, wave information can be more easily analyzed based on the amplitude values ​​displayed by the frequency. More specifically, in roll-to-roll equipment, a problem exists where mechanical vibrations generated from roll 50 can be transmitted to the film (TF), potentially causing large ripples. Therefore, the use of Fast Fourier Transform has the advantage of being able to measure the intensity of the unique frequency of the film (TF) itself, from which the mechanical vibrations (i.e., noise) generated from roll 50 have been removed.

[0084] Furthermore, the amplitude value converted from the frequency signal can be determined by measuring values ​​at predetermined intervals. More specifically, the lateral displacement value of the thin film (TF) measured by the lateral displacement sensor 10 at predetermined time intervals can be converted into the amplitude value converted from the frequency signal. When the lateral displacement value of the thin film (TF) is measured within a predetermined time period, a predetermined portion of the thin film (TF) can be specified, and when the presence or absence of defects and ripples in the thin film (TF) is determined by the ripple determination unit 40, the defective portion of the thin film (TF) can also be easily specified. In summary, in order to clearly specify the portions of the thin film (TF) where ripples and defects occur, the lateral displacement value of the thin film (TF) can be determined by dividing it into predetermined time intervals.

[0085] After obtaining the converted amplitude value based on the frequency signal, the presence or absence of ripples in the thin film (TF) can be determined by comparing the converted amplitude value with a preset amplitude value based on the frequency signal. That is, by comparing the converted amplitude value calculated through actual measurement with a preset amplitude value (which serves as a benchmark for determining the presence or absence of ripples in the thin film (TF) and its good / defective quality), if the converted amplitude value falls outside a predetermined range within a specific frequency range, the thin film (TF) can be determined to be defective.

[0086] Here, a "preset amplitude value" can be determined using data obtained under conditions identical or most similar to those in the object to be measured and the measuring device before measuring the film's ripples. More specifically, in a film (TF) conveyed by a roll-to-roll inline conveyor, the degree and location of ripples, as well as the extent of defects caused by ripples, vary depending on the film (TF) thickness, unit weight, length in the width direction, tension applied to the film (TF), film conveying speed, separation distance between rollers 50, position of the lateral displacement sensor 10, and the mass of the film (TF) itself. Therefore, when selecting a roll-to-roll inline conveyor for conveying the film (TF) and the film (TF) to be conveyed, data that allows for the predetermined degree of defects can be obtained by reflecting the various conditions mentioned above.

[0087] These parameter values ​​can also be applied when conveying separators in the thin film (TF) corrugation determination system 1 according to an embodiment of this disclosure. That is, a preset displacement value can be calculated based on at least one of the following parameters: the distance between the rollers 50 of the roller-to-roll online device, the position of the lateral displacement sensor 10, the thickness and weight of the film, and the distance in the width direction. The calculated value can be divided into predetermined time intervals and stored as a preset displacement value based on a frequency signal via the aforementioned fast Fourier transform.

[0088] Subsequently, when the amplitude value of the frequency signal and a preset amplitude value fall outside a predetermined range according to the frequency range, the thin film (TF) can be determined to be defective. As described in more detail in the following embodiments, the frequency range used to determine good / defective quality can vary depending on the width of the thin film.

[0089] For example, the ripple determination unit 40 can determine whether the thin film (TF) has defects in a frequency range of 15 Hz or greater and 30 Hz or less. Alternatively, the ripple determination unit 40 can determine whether the thin film (TF) has defects in a frequency range of greater than 0 Hz and 2 Hz or less.

[0090] In summary, in the case of very narrow films, they are treated as one-dimensional samples like lines, and the natural frequency of the entire one-dimensional sample is measured using only a single displacement sensor, and the tension is then calculated using wave equations. However, this disclosure is for films with very wide widths, making one-dimensional analysis as described above impossible. Therefore, this disclosure utilizes two-dimensional data measured by two or more displacement sensors to generate unstructured signals, thereby enabling faster and more accurate determination of the good / defective quality of the film (TF).

[0091] Methods for implementing the present invention

[0092] Hereinafter, embodiments of a system 1 for determining the corrugations of a thin film according to the present disclosure are described.

[0093] Figure 3 A graph showing displacement values ​​measured by a displacement sensor in a thin-film corrugation determination system 1 according to an embodiment of the present disclosure is illustrated. Figure 4 A graph showing the amplitude values ​​of a frequency signal obtained by fast Fourier transform in a thin-film ripple determination system 1 according to an embodiment of the present disclosure is illustrated. Figure 5 A graph showing the amplitude values ​​of a frequency signal for each predetermined segment in a thin-film corrugation determination system 1 according to an embodiment of the present disclosure is illustrated. Figure 6 A graph is shown showing the frequency range used to determine the good / defective quality of a thin film in a thin film ripple determination system 1 according to an embodiment of the present disclosure.

[0094] Reference Figure 3 The diagram shows the displacement values ​​of the separator measured over a predetermined time period. To measure the displacement values ​​of the separator, a lateral displacement sensor 10 (Ch3) is mounted on one side of the separator in the width direction, spaced apart from the surface of the membrane. The displacement values ​​of the separator measured in real time can be divided into predetermined time intervals. Figure 3 The diagram shows a separator being transported at a speed of 200 meters per minute (mpm) and divided into 10 m units at intervals of approximately 3 seconds.

[0095] The displacement value of the separator itself measured by the lateral displacement sensor 10 can be converted and used, but the displacement value of the separator measured by the center displacement sensor 20 can also be corrected and used. That is, since the amplitude of the separator may vary due to the vibration of the separator conveying equipment itself, the displacement value at the center of the separator can be used as a reference and for data correction.

[0096] The displacement value of the separator obtained by the above method can be converted into an amplitude value based on the frequency signal using a Fast Fourier Transform. (Refer to...) Figure 4It can identify the amplitude of a frequency signal obtained through a fast Fourier transform.

[0097] By separating the values ​​into those measured over a predetermined time period, a predetermined portion of the film can be isolated and designated. (Refer to...) Figure 5 The figure shows the amplitude values ​​measured 20 times in a range greater than 0 Hz and 30 Hz or less, divided into 10-second segments.

[0098] Subsequently, the preset amplitude value of the frequency signal is compared with the converted amplitude value to determine whether ripples exist in the film, and when the converted amplitude value falls outside the predetermined range, the separator of that part can be determined to be defective.

[0099] Reference Figure 6 (a) confirms that the preset amplitude value and the converted amplitude value differ within the range of 15 Hz or greater and 30 Hz or less. Additionally, refer to... Figure 6 (b) can confirm that the preset amplitude value and the converted amplitude value differ within a range greater than 0 Hz and 2 Hz or less. The frequency difference can vary depending on various variables, but in embodiments of this disclosure, it is used to determine quality ( Figure 6 (Good parts) / Defects Figure 6 The reference frequency range of the NG part (in the middle part) is formed differently depending on the size of the width direction of the separator.

[0100] It can be confirmed, such as Figure 6 In (a), when the width of the separator is 600 mm, it is easier to determine the good / defective quality of the separator in the frequency range of 15 Hz or greater and 30 Hz or less, and as... Figure 6 In (b), when the width of the separator is 1200 mm, it is easier to determine the good / defective quality of the separator in a frequency range greater than 0 Hz and 2 Hz or less.

[0101] Figure 7 A graph showing the relationship between signal processing and ripple size in a thin film ripple determination system according to an embodiment of the present disclosure for determining the good / defective quality of a thin film.

[0102] Reference Figure 7 The graph shows the relationship between the amplitude of the ripple processed in the frequency range greater than 0 Hz and 2 Hz or less, and the signal processing value. Good separators are shown in the lower left of the graph, while defective separators are shown in the upper right. That is, it can be confirmed that the actual signal processing results for portions falling outside the predetermined ripple range (here, less than 25 mm) also fall outside the predetermined range.

[0103] Therefore, this disclosure allows for a more readily determined presence or absence of ripples and the good / defective quality of the resulting separators, based solely on signal processing values.

[0104] Although the present disclosure has been described above with reference to limited embodiments, the present disclosure is not limited thereto, and it will be apparent to those skilled in the art that various modifications and variations can be made within the scope of the technical concept of the present disclosure and the equivalents of the described claims.

Claims

1. A film corrugation determination system, the system being used to determine corrugations in a roll-to-roll inline device for conveying a film in a longitudinal direction due to tension acting on the film and non-uniformity of the film material, the film being formed to have a predetermined dimension in the width direction and extending in the longitudinal direction, the system comprising: A lateral displacement sensor is mounted on one or more sides of the thin film in the width direction, spaced apart from the surface of the thin film, and is configured to measure the displacement of the surface of the thin film. as well as A ripple determination unit is configured to convert a time-dependent lateral displacement value of the thin film surface measured by the lateral displacement sensor into an amplitude value based on a frequency signal, and compare the converted amplitude value with a preset amplitude value based on the frequency signal to determine the presence or absence of ripples in the thin film.

2. The thin-film ripple determination system according to claim 1, wherein, The lateral displacement sensor measures the displacement of the film surface by irradiating light perpendicularly toward the surface of the film.

3. The thin-film ripple determination system according to claim 2, wherein, The displacement of the thin film surface is measured by the angle and wavelength of light reflected from the thin film surface by light irradiated from the lateral displacement sensor.

4. The thin-film ripple determination system according to claim 2, wherein, The lateral displacement sensor is a laser sensor.

5. The thin-film corrugation determination system according to claim 1, wherein, The ripple determination unit determines that the film is defective when the converted amplitude value falls outside a predetermined range based on the preset amplitude value.

6. The thin film ripple determination system of claim 1 further includes a center displacement sensor, the center displacement sensor being mounted at the center of the thin film in the width direction, spaced apart from the surface of the thin film, and configured to measure the displacement of the surface of the thin film.

7. The thin film ripple determination system according to claim 6 further includes a calibration unit for correcting the lateral displacement value of the thin film measured by the lateral displacement sensor based on the center displacement value of the thin film measured by the center displacement sensor.

8. The thin-film ripple determination system according to claim 7, wherein, The calibration unit corrects the lateral displacement value by subtracting the center displacement value of the thin film, measured by the center displacement sensor, from the lateral displacement value of the thin film measured by the lateral displacement sensor.

9. The thin-film ripple determination system according to claim 7, wherein, The calibration unit corrects the lateral displacement value by dividing the lateral displacement value of the film measured by the lateral displacement sensor by the center displacement value of the film measured by the center displacement sensor.

10. The thin-film ripple determination system according to claim 5, wherein, The ripple determination unit determines the lateral displacement value of the thin film based on values ​​measured at predetermined time intervals.

11. The thin-film ripple determination system according to claim 10, wherein, The ripple determination unit identifies the portions of the film that have been determined to be defective by measuring the lateral displacement values ​​of the film at the predetermined time intervals.

12. The thin-film ripple determination system according to claim 5, wherein, The ripple determination unit determines whether the thin film has defects in a frequency range of 15 Hz or greater and 30 Hz or less.

13. The thin-film ripple determination system according to claim 5, wherein, The ripple determination unit determines whether the thin film has defects in a frequency range greater than 0 Hz and 2 Hz or less.

14. The thin-film ripple determination system according to claim 5, wherein, The ripple determination unit calculates the preset amplitude value based on at least one of the following parameters: the distance between the rollers of the roller-to-roll online device, the position of the lateral displacement sensor, the thickness, weight, and distance of the film in the width direction, the tension acting on the film, and the conveying speed of the film.

15. The thin-film ripple determination system according to claim 5, wherein, The ripple determination unit uses a fast Fourier transform when converting the measured time-based lateral displacement value of the thin film into the converted amplitude value based on a frequency signal.

16. The thin-film ripple determination system according to claim 1, wherein, The lateral displacement sensor is configured to be spaced from the end of the film by more than 0 cm and 5 cm or less in the width direction of the film.

17. The thin film ripple determination system according to claim 1 further includes a display unit, the display unit being used to output the converted amplitude value in real time.

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