System for determining waviness of thin film being conveyed

Abstract

The present invention provides a system for determining waviness in a thin film, which has a certain size in the width direction and extends in the longitudinal direction, caused by unevenness of a thin film material and tension that acts on the thin film in a roll-to-roll in-line device conveying the thin film in the longitudinal direction. The system comprises: a side displacement sensor that is installed at one or more positions on both sides of the thin film in the width direction, spaced apart from the surface of the thin film, and measures the displacement of the surface of the thin film; and a waviness determination unit that converts a side surface displacement value of the thin film measured by the side displacement sensor over time into a magnitude value based on a frequency signal, compares the magnitude value with a preset magnitude value based on the frequency signal, and determines whether the thin film has waviness.

Description

A system for determining the swell of a thin film being transported

[0001] This invention 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] The present invention relates to a system for determining the ripple of a thin film, and more specifically, to a system for converting data measured by a displacement sensor in real time to determine the ripple occurring in a roll-to-roll device of a separation membrane and the resulting quality / defect of the separation membrane.

[0003]

[0004] The separator is a conductive membrane that isolates the two electrode parts of a secondary battery, preventing them from physically contacting each other and providing a passage for ions to move through micropores. To increase the process speed, each process can be performed using a roll-to-roll device using multiple rolls.

[0005] The roll-to-roll process applies tension to the separator by rotating the rolls on both sides to wind the rolls wound on one roll onto the other. However, during the drying process of the Safety Reinforced Separator (SRS) coating process, the gap between the rolls is formed very wide to prevent the coating from touching the rolls before drying. This gap between the rolls and the weak tension applied to the separator cause ripples in the separator, and if the width of the ripples formed in the separator is large, the separator may be damaged by contact with the top and bottom of the drying device.

[0006] Therefore, in order to predict whether the membrane is damaged due to the wind, an incoming quality control (IQC) is conducted to check for any abnormalities in the fabric.

[0007] However, conventional IQC methods collect and test a portion of a sample before the process begins. This can lead to concerns about the representativeness of the sample. Furthermore, individual samples are tested individually, which is costly and time-consuming. Furthermore, sample extraction can damage the target object. Furthermore, since sample extraction and measurement are performed manually, separate from the process, the accuracy of the resulting data can also be questionable.

[0008] In conclusion, the existing inspection method, IQC, not only cannot detect defective products in real time, but also has many shortcomings in terms of cost, time, and accuracy.

[0009] The background technology described above is technical information that the inventor possessed for the purpose of deriving embodiments of the present invention or acquired during the derivation process, and cannot necessarily be said to be publicly known technology disclosed to the general public prior to the filing of the embodiments of the present invention.

[0010]

[0011] In order to solve the above problem, the present invention provides a thin film swell judgment system that installs a displacement sensor in a roll-to-roll device at a distance from the surface of the separation membrane, converts the measured displacement value of the separation membrane into a size value according to a frequency signal, and compares it with a preset size value to determine the occurrence of swell and quality / defect of the thin film.

[0012]

[0013] A system for judging swell of a thin film according to one embodiment of the present invention is a system for judging swell of a thin film caused by tension acting on the thin film and non-uniformity of the thin film material in a roll-to-roll inline device that transports a thin film formed by having a predetermined size in the width direction and extending in the length direction in the length direction, and may include a lateral displacement sensor installed at least at one or more positions on both sides of the width direction of the thin film and spaced apart from the surface of the thin film, and measuring the displacement of the thin film surface, and a swell judging unit that converts the lateral displacement value of the thin film surface over time measured by the lateral displacement sensor into a size value according to a frequency signal, and compares it with a preset size value according to the frequency signal to determine whether swell occurs in the thin film.

[0014] According to one embodiment of the present invention, the lateral displacement sensor can measure the displacement of the thin film surface by irradiating light perpendicularly toward the surface of the thin film.

[0015] According to one embodiment of the present invention, the displacement of the thin film surface can be measured by the angle and wavelength of light reflected from the thin film surface by the light irradiated from the lateral displacement sensor.

[0016] According to one embodiment of the present invention, the lateral displacement sensor may be a laser sensor.

[0017] According to one embodiment of the present invention, the thin film determination unit may be characterized in that if a size value converted based on a preset size value falls outside a predetermined range, the thin film is determined to be defective.

[0018] According to one embodiment of the present invention, a central displacement sensor may be further included, which is installed in the center of the width direction of the thin film and spaced apart from the thin film surface, and measures the displacement of the thin film surface.

[0019] According to one embodiment of the present invention, a calibration unit may further be included that corrects a side displacement value of a thin film measured by a side displacement sensor based on a central displacement value of the thin film measured by a central displacement sensor.

[0020] According to one embodiment of the present invention, the calibration unit can correct the lateral displacement value of the thin film measured by the lateral displacement sensor by subtracting the central displacement value of the thin film measured by the central displacement sensor.

[0021] According to one embodiment of the present invention, the calibration unit can compensate by dividing the central displacement value of the thin film measured by the central displacement sensor by the lateral displacement value of the thin film measured by the lateral displacement sensor.

[0022] According to one embodiment of the present invention, the swell determination unit may be characterized in that it determines the lateral displacement value of the thin film based on a value measured at a predetermined time interval.

[0023] According to one embodiment of the present invention, the swell judgment unit may be characterized by specifying a portion of the thin film that is judged to be defective through a lateral displacement value of the thin film measured at a predetermined time interval.

[0024] According to one embodiment of the present invention, the swell judgment unit may be characterized in that it judges whether the thin film is defective within a frequency range of 15 Hz or more and 30 Hz or less.

[0025] According to one embodiment of the present invention, the swell judgment unit may be characterized in that it judges whether the thin film is defective within a frequency range exceeding 0 Hz and less than or equal to 2 Hz.

[0026] According to one embodiment of the present invention, the swell determination unit can calculate a preset size value based on at least one parameter among the distance between rolls of a roll-to-roll inline device, the position of a lateral displacement sensor, the thickness, weight, and width direction of the thin film, the tension acting on the thin film, and the transport speed of the thin film.

[0027] According to one embodiment of the present invention, the wave determination unit may be characterized by using a fast Fourier transform when converting a displacement value of a side surface of a thin film according to a measured time into a transformed size value according to a frequency signal.

[0028] According to one embodiment of the present invention, the lateral displacement sensor may be formed to be spaced apart from an end of the thin film by a distance of more than 0 cm and less than 5 cm in the width direction of the thin film.

[0029] According to one embodiment of the present invention, a display unit for outputting the converted size value in real time may be further included.

[0030]

[0031] The present invention automatically inspects the ripples occurring in the separation membrane, thereby reducing costs and time.

[0032] In addition, the present invention corresponds to a full inspection of a separation membrane, and is superior in terms of yield because it does not use the existing method of extracting a sample and inspecting only a portion that damages the target object.

[0033] Additionally, the defective parts of the membrane can be more easily identified through data measured in real time.

[0034] Additionally, since the set value is calculated based on various variables that occur during the process, it is easier to find the cause of the noise.

[0035] In addition, since it is easy to quantify the swell of the membrane and identify the swell trend according to the process method or lot (bundle unit), it has the effect of removing defects in advance at the process stage.

[0036] The effects that can be obtained from the invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention belongs from the description below.

[0037]

[0038] FIG. 1a and FIG. 1b illustrate photographs of a thin film swell determination system (1) according to one embodiment of the present invention.

[0039] FIG. 2 illustrates a block diagram of a thin film swell determination system (1) according to one embodiment of the present invention.

[0040] FIG. 3 illustrates a graph of displacement values ​​measured by a displacement sensor in a thin film swell determination system according to an embodiment of the present invention.

[0041] FIG. 4 shows a graph of size values ​​according to frequency signals through fast Fourier transform in a thin film swell determination system according to an embodiment of the present invention.

[0042] FIG. 5 illustrates a graph of size values ​​according to frequency signals for each predetermined section in a thin film swell determination system according to an embodiment of the present invention.

[0043] FIG. 6 is a graph showing a range of frequencies for determining the quality / defect of a thin film in a thin film swell determination system according to an embodiment of the present invention.

[0044] FIG. 7 is a graph showing the relationship between the size of the wave and signal processing for determining the quality / defect of a thin film in a thin film wave judgment system according to one embodiment of the present invention.

[0045] ※ Explanation of symbols

[0046] 1: Thin film swell judgment system

[0047] 10: Lateral displacement sensor

[0048] 20: Central displacement sensor

[0049] 30: Calibration section

[0050] 40: The Noul Judgement Committee

[0051] 50: Roll

[0052] 60: Display section

[0053] TF: Thin film

[0054]

[0055] The present invention will become clearer with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided only to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. The present invention is defined solely by the scope of the claims. Meanwhile, the terminology used in this specification is for the purpose of describing the embodiments and is not intended to limit the present invention.

[0056] Throughout this specification, singular forms also include plural forms unless specifically stated otherwise in the text.

[0057] Throughout this specification, the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components, steps, operations and / or elements, and do not exclude other components unless specifically stated to the contrary, but rather include other components.

[0058] Additionally, terms such as “unit” described throughout this specification mean a unit that processes at least one function or operation, which may be implemented as hardware or software, or a combination of hardware and software.

[0059] Additionally, when it is said throughout this specification that a part is "connected" to another part, this includes not only cases where it is "directly connected" but also cases where it is connected "with another structure in between."

[0060]

[0061] Hereinafter, the present invention will be described in more detail.

[0062] The present invention relates to a system for determining the presence of ripples in a thin film, and is intended to automatically determine whether a thin film is damaged due to ripples generated in a roll-to-roll device that operates by rotating a roll wound on one roll and winding it on another roll. The thin film is a film having a predetermined width and length, and can be extended in the longitudinal direction and wound on a plurality of rolls. The plurality of rolls can rotate in the same direction to transport the thin film from one roll to the other.

[0063] Thin films transported by roll-to-roll equipment are wound at both ends and rotated for transport. Therefore, due to the tension acting on the thin film and the characteristics of the material, some degree of swell may occur. While swell within a certain range is not a problem, if it exceeds a certain range, the film may be damaged.

[0064] Here, the term "film" is not specifically limited to a thin film transported in a roll-to-roll device, but may be a "separator" as an example. A separator is a conductive film that isolates the two electrode portions of a secondary battery, preventing them from physically contacting each other, and provides a passage for ions to move through micropores.

[0065] Hereinafter, the present invention will describe in more detail a system (1) for determining whether or not a swell occurs in a roll-to-roll inline device that transports a separation membrane.

[0066] FIG. 1a and FIG. 1b illustrate photographs of a thin film swell determination system (1) according to an embodiment of the present invention, and FIG. 2 illustrates a block diagram of a thin film swell determination system (1) according to an embodiment of the present invention.

[0067] Referring to FIGS. 1a, 1b and 2, a thin film swell determination system (1) according to one embodiment of the present invention may include a lateral displacement sensor (10) and a swell determination unit (40).

[0068] The lateral displacement sensor (10) is a sensor that measures the displacement of the thin film (TF), and can be installed in parallel in the width direction of the thin film (TF). In particular, referring to FIGS. 1A and 1B, the lateral displacement sensor (10) is formed on a width-direction side surface of the thin film (TF), and can determine whether a swell is formed at the side end of the thin film (TF).

[0069] The lateral displacement sensor (10) may be formed at at least one position on either side of the width direction of the thin film (TF). That is, referring to FIG. 1B, it may be installed on the right surface or the left surface of the thin film (TF) with respect to the transport direction of the thin film (TF), or may be installed on both the right and left surfaces. Since the swell generated in the thin film (TF) may occur independently regardless of the right or left side, the swell generation position of the thin film (TF) transported through the roll-to-roll inline device can be more accurately determined depending on the number of lateral displacement sensors (10) installed.

[0070] In addition, the lateral displacement sensor (10) can be placed between rolls (50) in a roll-to-roll inline device to measure the swell of the thin film (TF). That is, FIG. 1b shows a front view of a case where the lateral displacement sensor (10) is placed between rolls (50) as in FIG. 1a, rather than being formed on a thin film (TF) formed on the upper side of the roll (50).

[0071] The lateral displacement sensor (10) can be formed at a predetermined distance from the surface of the thin film (TF), which can be adjusted differently depending on the degree of swell generation and the type of sensor.

[0072] Referring to Fig. 1b, a lateral displacement sensor (10) is provided on the upper side of the surface of the thin film (TF) and can measure the distance from the surface of the thin film (TF). Unlike a rigid body such as a metal, the occurrence and degree of swell of the thin film (TF) differ depending on not only the characteristics of the thin film (TF) itself but also the tension of the rolls (50) on both sides that transport the thin film. Therefore, in the case of the thin film (TF), the occurrence of swell of the thin film (TF) can be determined by measuring the degree of swell that occurs on both sides (right and / or left) of the thin film.

[0073] In particular, the lateral displacement sensor (10) can irradiate light (L) vertically toward the surface of the thin film (TF). The irradiated light (L) can be reflected from the surface of the thin film (TF) and then received by the lateral displacement sensor (10). Accordingly, the displacement of the surface of the thin film (TF) can be measured depending on the angle and wavelength of the light (L) irradiated and reflected.

[0074] In one embodiment, the lateral displacement sensor (10) may be a laser sensor to measure the distance of the surface of the thin film (TF). The laser sensor is a sensor that measures the distance to a target object using laser light (L). By receiving the light reflected from the surface of the thin film (TF) by the laser light (L) irradiated from the lateral displacement sensor (10), the displacement of the surface of the thin film (TF) can be measured as a change in time according to the travel distance of the laser light (L).

[0075] In addition, the lateral displacement sensor (10) may be formed at a predetermined distance from the end of the thin film (TF) in the width direction of the thin film (TF). In particular, in the present invention, when the thin film (TF) is a separator, it may be formed within a range of more than 0 cm and less than 5 cm from the end of the thin film (TF). In the case of the above range, the range of damage caused by the ripple formed in the separator can be more easily determined.

[0076] Meanwhile, the thin film swell determination system (1) according to one embodiment of the present invention may further include a central displacement sensor (20) that measures the displacement formed in the central portion of the thin film (TF) surface, in addition to the lateral displacement sensor (10).

[0077] The central displacement sensor (20) may be installed at the center of the width direction of the thin film (TF) and spaced apart from the surface of the thin film (TF) by a predetermined distance. The displacement value of the center of the width direction of the thin film (TF) measured by the central displacement sensor (20) can determine whether the thin film (TF) is swelled or not by itself, but can also be used as a value for correcting the displacement value of the thin film (TF) measured by the side displacement sensor (10). More specifically, the displacement value of the thin film (TF) measured by the central displacement sensor (20) can be calibrated by the displacement value of the thin film (TF) measured by the side displacement sensor (10) to more accurately measure whether swell occurs in the thin film (TF) through a calibration process.

[0078] Accordingly, the present invention may further include a calibration unit (30) that performs such a correction process. The calibration unit (30) may correct the displacement value of the thin film (TF) in various ways. In one embodiment, the calibration unit (30) may correct by subtracting the central displacement value of the thin film (TF) measured by the central displacement sensor from the lateral displacement value of the thin film (TF) measured by the lateral displacement sensor (10), or may correct by dividing the central displacement value of the thin film (TF) measured by the central displacement sensor from the lateral displacement value of the thin film (TF) measured by the lateral displacement sensor (10).

[0079] In this case, it is possible to more easily determine whether a swell is formed in the thin film (TF) through the difference in size or ratio between the displacement of the central part and the displacement of the side parts of the thin film (TF). That is, since the roll (50) that transports the thin film (TF) is a rigid body, it is generally difficult to distinguish whether the swell generated in the thin film (TF) transported between the rolls (50) is a mechanical vibration generated in the roll (50) or a swell generated in the thin film (TF) itself. Therefore, by separately measuring the displacement of the central part, it is possible to detect the mechanical vibration generated in the roll (50) and calibrate it with the displacement of the side parts, thereby more clearly determining whether a swell is formed in the thin film (TF) itself.

[0080] A thin film swell determination system (1) according to one embodiment of the present invention may further include a swell determination unit (40) capable of determining swells generated in a thin film (TF) using data measured from a lateral displacement sensor (10).

[0081] The swell determination unit (40) can determine whether there is a swell by converting the displacement value of the thin film (TF) surface measured by the lateral displacement sensor (10) into a magnitude value. That is, the lateral displacement sensor (10) can measure the lateral displacement value of the thin film (TF) surface when the thin film (TF) is transported, and derive the lateral displacement value of the thin film (TF) surface according to the measured time. This displacement value of the thin film (TF) surface according to time can be converted into a magnitude value according to a frequency signal, and whether there is a swell of the thin film (TF) can be determined by comparing this value with a preset magnitude value. In conclusion, if the converted magnitude value based on the preset magnitude value within the range of a specific frequency signal does not fall outside a predetermined range, it can be determined as a good product, and if it falls outside the predetermined range, it can be determined as a defective product.

[0082] In addition, the converted size value converted through the swell judgment unit (40) can be directly output. More specifically, a display unit (60) that outputs the converted size value so that the worker can check the degree of the swell in real time can be further included. The display unit (60) is a visual device that outputs the swell size value in the form of numbers or the like, and according to one embodiment, it can be an LCD, but this is not limited to a specific embodiment.

[0083] Finally, since the converted size value of the wave formed on the thin film (TF) can be separately calculated through the display unit (60), the degree of the wave formed on the thin film (TF) can be provided to the operator in real time.

[0084] The calibration unit (30) and the swell determination unit (40) are a type of microprocessor and can be composed of a calculation unit and a control unit. This is a configuration that produces desired data through a set associative process based on input data, and a general chip-shaped processing unit used in devices such as computers can be used.

[0085] Hereinafter, whether or not the thin film (TF) is judged to be wavy according to the wavy judgment unit (40) will be described in more detail.

[0086] When converting the lateral displacement value of a thin film (TF) according to the measured time into a transformed size value according to a frequency signal, a fast Fourier transform (FFT) can be used. The fast Fourier transform is a method of providing frequency information about a signal by converting a measured signal into individual spectral components. In the present invention, the lateral displacement value of a thin film (TF) is sampled for a predetermined time while the thin film (TF) is transported along a roll-to-roll device, divided into frequency components, and then expressed as a separate frequency each having its own amplitude and phase.

[0087] Ultimately, it can be easier to analyze wave information through the magnitude value displayed according to frequency. More specifically, in a roll-to-roll device, there is a problem that mechanical vibration generated from the roll (50) can be transmitted to the thin film (TF), which can cause large swells. Therefore, there is an advantage in that the intensity of the mechanical vibration generated from the roll (50), i.e., the unique frequency of the thin film (TF) itself with noise removed, can be measured using a fast Fourier transform.

[0088] In addition, the converted size value according to the frequency signal can be determined through the values ​​measured at a predetermined interval. More specifically, the lateral displacement value of the thin film (TF) measured by the lateral displacement sensor (10) can be converted into the converted size value according to the frequency signal at a predetermined time interval. When the lateral displacement value of the thin film (TF) is measured for a predetermined time, a predetermined portion of the thin film (TF) can be specified, and when determining whether or not the thin film (TF) is swell-shaped or defective according to the swell determination unit (40), the defective portion of the thin film (TF) can also be easily specified. In conclusion, in order to clearly specify the portion where swell-shaped or defective portion of the thin film (TF) has occurred, the lateral displacement value of the thin film (TF) can be determined by dividing it into a predetermined time interval.

[0089] After deriving the converted size value according to the frequency signal, it is possible to determine whether or not the thin film (TF) has swelled by comparing it with a preset size value according to the frequency signal. In other words, the converted size value derived through actual measurement is compared with the preset size value, which serves as a standard for determining whether or not swell has occurred and whether or not the thin film (TF) is good or bad, and if it deviates from a predetermined range in a specific frequency range, the thin film (TF) can be determined to be defective.

[0090] Here, the 'preset size value' can be determined through data obtained under the same or most similar conditions as the target to be measured and the measuring device prior to measuring the swell of the thin film. More specifically, the thin film (TF) transported by the roll-to-roll inline device has different degrees and locations of swells, and different degrees of defects caused by swells depending on the thickness, unit weight, width direction length, tension applied to the thin film (TF), transport speed of the thin film (TF), separation distance between rolls (50) and rolls (50), position of the lateral displacement sensor (10), quality of the thin film (TF) itself, etc. Therefore, when a roll-to-roll inline device for transporting the thin film (TF) and the thin film (TF) to be transported are selected, data capable of determining the degree of defects in advance can be obtained by reflecting the various conditions mentioned above.

[0091] These parameter values ​​can also be applied when transporting a membrane in a thin film (TF) swell determination system (1) according to an embodiment of the present invention. That is, a preset displacement value can be calculated based on at least one parameter among the distance between the rolls (50) of the roll-to-roll inline device, the position of the lateral displacement sensor (10), the thickness, weight, and width direction distance of the thin film (TF). The calculated value can be divided into predetermined time intervals and stored as a preset displacement value according to a frequency signal through the fast Fourier transform mentioned above.

[0092] Thereafter, if the size value based on the frequency signal and the preset size value fall outside a predetermined range according to the frequency range, the thin film (TF) can be judged as defective. As described in more detail through the examples below, the frequency range for judging good / defective may vary somewhat depending on the width of the separator.

[0093] For example, the swell judgment unit (40) can judge whether the thin film (TF) is defective within a frequency range of 15 Hz or more and 30 Hz or less. Alternatively, the swell judgment unit (40) can judge whether the thin film (TF) is defective within a frequency range of 0 Hz or more and 2 Hz or less.

[0094] In conclusion, for very narrow thin films, they are treated as one-dimensional samples like threads, and the natural frequency of the entire one-dimensional sample is measured using only one displacement sensor, and the tension is calculated using the wave equation. However, the present invention targets very wide thin films, so the one-dimensional analysis as described above is impossible. Therefore, the present invention can more quickly and accurately determine the quality / defect of thin films (TF) by generating an unstructured signal using two-dimensional data measured by two or more displacement sensors.

[0095]

[0096] Below is an example of a system (1) for determining the thickness of a thin film according to the present invention.

[0097] FIG. 3 illustrates a graph of a displacement value measured by a displacement sensor in a thin film swell determination system (1) according to an embodiment of the present invention, FIG. 4 illustrates a graph of a size value according to a frequency signal through a fast Fourier transform in a thin film swell determination system (1) according to an embodiment of the present invention, FIG. 5 illustrates a graph of a size value according to a frequency signal for each predetermined section in a thin film swell determination system (1) according to an embodiment of the present invention, and FIG. 6 illustrates a graph of a frequency range for determining the quality / defect of a thin film in a thin film swell determination system (1) according to an embodiment of the present invention.

[0098] Referring to Fig. 3, the displacement value of the membrane measured over a predetermined period of time is shown. In order to measure the displacement value of the membrane, a lateral displacement sensor (10, Ch3) is installed at a position on one side of the width direction of the membrane, spaced apart from the surface of the thin film. The displacement value of the membrane measured in real time can be divided into predetermined time intervals. In the case of Fig. 3, the separation membrane transported at a speed of 200 mpm (meters per minute) is divided into approximately 3-second intervals to divide it into 10-meter units.

[0099] The displacement value of the membrane measured by the side displacement sensor (10) can be converted and used, but the displacement value of the membrane measured by the central displacement sensor (20) can also be used after being corrected. That is, since the amplitude of the membrane can be formed differently due to the vibration of the membrane transport device itself, the displacement value at the center of the membrane can serve as a reference and be used for data correction.

[0100] The displacement value of the membrane obtained by the above method can be converted into a size value according to a frequency signal through a fast Fourier transform. Referring to Fig. 4, the size according to the frequency signal derived through the fast Fourier transform can be confirmed.

[0101] By separating this into values ​​measured over a given period of time, a specific portion of the thin film can be isolated and specified. Referring to Fig. 5, the magnitude values ​​in the range of 0 Hz to 30 Hz, measured 20 times in a portion divided into 10-second units, are shown.

[0102] Afterwards, by comparing the preset size value and the converted size value according to the frequency signal, it is determined whether or not the thin film is wavy, and if the converted size value is outside a predetermined range, the membrane in that part can be determined to be defective.

[0103] Referring to (a) of Fig. 6, it can be confirmed that the preset size value and the converted size value differ in the range of 15 Hz to 30 Hz. In addition, referring to (b) of Fig. 6, it can be confirmed that the preset size value and the converted size value differ in the range of 0 Hz to 2 Hz. The difference according to frequency may be formed differently depending on various variables, but in the case of the embodiment of the present invention, the range of frequencies that serve as the standard for judging good (Good part in Fig. 6) / bad (NG part in Fig. 6) is formed differently depending on the size in the width direction of the separation membrane.

[0104] In the case where the width of the membrane is 600 mm, as in the former, it can be confirmed that it is easier to judge the quality / defect of the membrane in the frequency range of 15 Hz to 30 Hz, and in the case where the width of the membrane is 1200 mm, as in the latter, it can be confirmed that it is easier to judge the quality / defect of the membrane in the frequency range of 0 Hz to 2 Hz.

[0105] FIG. 7 illustrates a graph of the relationship between the size of a wave and signal processing for determining the quality / defect of a thin film in a thin film wave judgment system according to one embodiment of the present invention.

[0106] Referring to Figure 7, the relationship between the size of the swell and the signal processing values ​​processed in the frequency range exceeding 0 Hz and 2 Hz or less is illustrated. A good separator is indicated in the lower left of the graph, and a defective separator is indicated in the upper right of the graph. In other words, it can be confirmed that the actual signal processing results also fall outside the specified swell range (here, less than 25 mm).

[0107] As a result, the present invention can more easily determine whether a ripple has occurred and the resulting quality / defect of the membrane using only signal processing values.

[0108] Although the present invention has been described above with reference to limited embodiments, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. A system for determining the tension acting on the thin film and the swell of the thin film caused by the non-uniformity of the thin film material in a roll-to-roll inline device that transports the thin film formed by extending in the length direction and having a predetermined size in the width direction in the length direction. A lateral displacement sensor installed at least at one or more locations on either side of the width direction of the thin film and spaced apart from the surface of the thin film, and measuring the displacement of the surface of the thin film; A thin film swell determination system including a swell determination unit that converts the lateral displacement value of the thin film surface over time measured by the lateral displacement sensor into a size value according to a frequency signal and compares it with a preset size value according to the frequency signal to determine whether swell occurs in the thin film.

2. In paragraph 1, The above lateral displacement sensor, A thin film swell determination system characterized by measuring the displacement of the thin film surface by irradiating light perpendicularly toward the surface of the thin film.

3. In paragraph 2, A thin film swell determination system characterized in that the displacement of the thin film surface is measured by the angle and wavelength of the light reflected from the thin film surface by the light irradiated by the side displacement sensor.

4. In paragraph 2, The above lateral displacement sensor, A thin film swell determination system characterized by a laser sensor.

5. In paragraph 1, The above-mentioned swell judgment part is, A thin film swell judgment system characterized in that if the converted size value falls outside a predetermined range based on the above-described preset size value, the thin film is judged to be defective.

6. In paragraph 1, A thin film swell determination system further comprising a central displacement sensor installed at a center of the width direction of the thin film and spaced apart from the thin film surface, the central displacement sensor measuring the displacement of the thin film surface.

7. In paragraph 6, A thin film swell determination system further comprising a calibration unit that corrects the side displacement value of the thin film measured by the side displacement sensor based on the central displacement value of the thin film measured by the central displacement sensor.

8. In paragraph 7, The above calibration unit, A system for judging the swell of a thin film, wherein the lateral displacement value of the thin film measured by the lateral displacement sensor is subtracted from the central displacement value of the thin film measured by the central displacement sensor to compensate for the lateral displacement value of the thin film measured by the lateral displacement sensor.

9. In paragraph 7, The above calibration unit, A system for determining the swell of a thin film, wherein the central displacement value of the thin film measured by the central displacement sensor is divided by the lateral displacement value of the thin film measured by the lateral displacement sensor to compensate for the difference.

10. In paragraph 5, The above-mentioned swell judgment part is, A thin film swell determination system characterized in that the lateral displacement value of the thin film is determined based on values ​​measured at predetermined time intervals.

11. In paragraph 10, The above-mentioned swell judgment part is, A thin film swell judgment system characterized in that a portion of the thin film is identified as defective through a lateral displacement value of the thin film measured at a predetermined time interval.

12. In paragraph 5, The above-mentioned swell judgment part is, A thin film ripple judgment system characterized in that it judges whether the thin film is defective within a frequency range of 15 Hz or more and 30 Hz or less.

13. In paragraph 5, The above-mentioned swell judgment part is, A thin film ripple judgment system characterized in that it judges whether the thin film is defective within a frequency range exceeding 0 Hz and below 2 Hz.

14. In paragraph 5, The above-mentioned swell judgment part is, A system for determining the swell of a thin film, which calculates the preset size value based on at least one parameter among the distance between the rolls of the roll-to-roll inline device, the position of the lateral displacement sensor, the thickness of the thin film, the weight, the distance in the width direction, the tension acting on the thin film, and the transport speed of the thin film.

15. In paragraph 5, The above-mentioned swell judgment part is, A thin film swell determination system characterized in that a fast Fourier transform is used when converting the lateral displacement value of the thin film according to the measured time into the transformed size value according to the frequency signal.

16. In paragraph 1, The above lateral displacement sensor, A system for judging the swell of a thin film, wherein the swell is formed at a distance of more than 0 cm and less than 5 cm from the end of the thin film in the width direction of the thin film.

17. In paragraph 1, A thin film swell determination system further comprising a display unit that outputs the converted size value in real time.

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