Film temperature and thickness measuring device and measurement method using the same

Abstract

The present invention relates to a film temperature and thickness measuring device and a measuring method using the same, which sequentially measures the surface temperature and thickness of a film being extruded or coated in an in-line manner at the same point, and controls the film temperature and thickness based on the measured data, thereby enabling the production of a film with a uniform thickness.

Description

Technical Field

[0001] The present invention claims the benefit of the filing date of Korean Patent Application No. 10-2022-0140518, filed with the Korean Intellectual Property Office on October 27, 2022, and all of its contents are incorporated herein by reference. The present invention relates to a film temperature and thickness measuring device capable of sequentially measuring the temperature and thickness of a film during the manufacturing process of a polymer film using an in-line method, and a measuring method using the same.

Background Art

[0002] Generally, a porous film-shaped polymer film is used as a separator for secondary batteries. The polymer film is usually manufactured by forming a molten polymer resin discharged from an extruder into a film shape and then undergoing stretching and heat fixation processes.

[0003] Such a film manufacturing process is performed in an in-line method with a roll-to-roll structure, and the resulting product is in the form of a rectangular separator mother roll, which is subsequently cut into a predetermined size and then used as a separator substrate.

[0004] The polymer film used for the separator preferably has a uniform thickness variation across the entire separator to improve product yield. Therefore, it is necessary to measure the thickness during the extrusion process of the polymer film to control the thickness uniformity of the manufactured film.

[0005] Conventionally, only the thickness of the polymer film has been mainly measured, but due to the real-time process temperature caused by the thermal expansion coefficient of the polymer material, the thickness of the manufactured film may change. When such a difference in film thickness uniformity occurs, product defects may occur in subsequent processes due to undulations and thickness variations of the material.

[0006] Currently, there is no real-time measurement method for changes in film temperature, making it impossible to measure and predict changes in film thickness based on temperature. Therefore, conventionally, after changing the process, products were manufactured through sampling-based thickness measurement, sample measurement based on material properties, and instrument calibration.

[0007] Specifically, as shown in Figure 1, conventionally, after the film 1 was extruded by the extruder 10, the thickness of the film 1 was measured in a separate process using a scanning-type loading level density meter 3. In this case, preliminary preparation work was required to confirm the thickness value of the product using the loading level density meter 3. That is, it was possible to confirm the thickness of the film 1 after calibration work using a sample of the film 1.

[0008] However, measuring the sample thickness of the film 1 can be done with the manufacturing equipment stopped after the rewinder of the winding roll 5, but there were cumbersome issues such as having to use a separate infrared surface infrared temperature sensor to measure the sample temperature of the film 1. [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention aims to solve the above-mentioned problems and provides a film temperature and thickness measuring device and a measurement method using the same, which sequentially measures the surface temperature and thickness of a film extruded or coated in an in-line manner at the same point, and enables the production of a film of uniform thickness by controlling the temperature and thickness of the film based on the measured data. [Means for solving the problem]

[0010] To achieve the above objective, the present invention provides a film temperature and thickness measuring device for measuring the temperature and thickness of a film to be extruded or coated, and includes: a conveying unit equipped with a rotating roll for conveying the film to be formed in one direction; a thickness measuring unit installed at a distance from the outer surface of the rotating roll for measuring the thickness of the conveyed film; a temperature measuring unit arranged adjacent to the thickness measuring unit for measuring the surface temperature of the conveyed film; and a control unit for determining whether the measured values ​​measured by the thickness measuring unit and the temperature measuring unit, respectively, exceed a reference value.

[0011] In this case, the temperature measuring unit and the thickness measuring unit are arranged on the same line as the film transport direction so that the surface temperature and thickness of the film at the same point on the transported film can be measured sequentially. Here, the thickness measuring unit and the temperature measuring unit are arranged in order from upstream to downstream in the film transport direction. Alternatively, the temperature measuring unit and the thickness measuring unit may be arranged in order from upstream to downstream in the film transport direction.

[0012] Furthermore, the thickness measuring unit may include a guide rail spaced parallel to the central axis of the rotating roll, a movable plate connected to the guide rail so as to be reciprocally movable by receiving power along the longitudinal direction of the guide rail, and a laser displacement sensor connected to the movable plate via a first bracket, which measures the thickness of the film by irradiating a laser toward the surface of the film being conveyed by the rotating roll.

[0013] Furthermore, the movable plate is coupled to the guide rail so as to be able to reciprocate in a direction intersecting the longitudinal direction, allowing the distance from the outer surface of the rotating roll to be adjusted. Furthermore, the first bracket may be coupled to the first hinge axis of the movable plate so as to be able to rotate by a predetermined angle along the film transport direction with the first hinge axis of the movable plate as the center of rotation, thereby allowing adjustment of the laser irradiation angle of the laser displacement sensor.

[0014] Furthermore, the temperature measuring unit may include a second bracket coupled to the first bracket so as to be able to move back and forth along a direction intersecting the longitudinal direction of the rotating roll, and an infrared temperature sensor provided on the second bracket for measuring the surface temperature of the film being conveyed by the rotating roll. Furthermore, the infrared temperature sensor may be coupled so as to be able to pivot by a predetermined angle along the film transport direction with the second hinge axis of the second bracket as the center of rotation, thereby allowing adjustment of the infrared irradiation position of the infrared temperature sensor.

[0015] Furthermore, when the film is extruded, the temperature measuring unit and the thickness measuring unit can measure at a proximity position within 0 to 30 mm along the transport direction of the film. Furthermore, when the film is being coated and molded, the temperature measuring unit and the thickness measuring unit can measure close proximity within 0 to 100 mm along the transport direction of the film.

[0016] On the other hand, the film temperature and thickness measurement method according to the present invention is The process may include: forming a film by an extrusion or coating process; transporting the formed film in one direction by a rotating roll; measuring the film temperature at a predetermined point by irradiating infrared light toward the surface of the film being transported by the rotating roll; measuring the film thickness by irradiating a laser at the same or nearby position on the surface of the film whose temperature has been measured; determining whether the measured values ​​of the film temperature and thickness exceed a reference value; and, if the measured values ​​exceed a reference value, changing the conditions of the film manufacturing process.

[0017] Here, the step of measuring the thickness of the film can be performed by first measuring the temperature of the film along the same line as the film's transport direction, and then measuring the thickness of the film, so that the surface temperature and thickness of the film can be measured sequentially at the same point on the transported film.

[0018] Alternatively, the step of measuring the temperature of the film may involve first measuring the thickness of the film along the same line as the film's transport direction, and then measuring the temperature of the film, so that the film's thickness and surface temperature can be measured sequentially at the same point on the transported film.

[0019] In this case, the step of measuring the thickness of the film may include: irradiating the surface of the rotating roll with a laser using a laser displacement sensor when the film is not being transported, measuring the outer diameter of the rotating roll and setting this as a base value; irradiating the surface of the film with a laser using the laser displacement sensor when the film is being transported using the rotating roll, measuring the distance measurement to the film; and subtracting the base value from the distance measurement to the film to derive the thickness of the film. [Effects of the Invention]

[0020] The film temperature and thickness measuring device and measurement method according to the present invention, configured as described above, sequentially measures the surface temperature and thickness of a film extruded or coated in an in-line manner at the same point, and by comparing the measured data with a reference value, it is possible to change the conditions of various film manufacturing processes or to go through processes such as heat fixation.

[0021] In other words, by using the film temperature and thickness measuring device according to the present invention, it is possible to predict in advance the temperature changes and material changes of the film being manufactured based on the temperature and thickness measurements of the film, and based on this, it is possible to manufacture a film of uniform thickness.

[0022] In particular, by sequentially measuring the temperature and thickness of the film at the same nearby location as it is transported after film extrusion or coating molding, the conventional process of measuring sample film products is eliminated, thereby shortening the time required for the manufacturing process. [Brief explanation of the drawing]

[0023] [Figure 1] Schematic diagram showing a conventional inline film manufacturing process [Figure 2] Schematic diagram showing an inline film manufacturing process to which the film temperature and thickness measuring device according to the present invention is applied [Figure 3] Schematic configuration diagram of the film temperature and thickness measuring device according to the present invention [Figure 4] Perspective view of the film temperature and thickness measuring device according to the present invention [Figure 5] Perspective view of the main part of the film temperature and thickness measuring device according to the present invention [Figure 6] Side view of the film temperature and thickness measuring device according to the present invention [Figure 7] Side view showing the structure of the thickness measuring part according to the present invention [Figure 8] Schematic diagram showing the thickness measuring principle of the thickness measuring part according to the present invention [Figure 9] Side view showing the structure of the temperature measuring part according to the present invention [Figure 10] Detailed view of the main part of the film temperature and thickness measuring device according to the present invention [Figure 11] Diagram showing the arrangement state of the film temperature and thickness measuring device according to the present invention [Figure 12] Flowchart showing the film temperature and thickness measuring process according to the present invention [Figure 13] Photograph substituting for a drawing comparing the film temperature and thickness measuring method according to the present invention with the conventional thickness measuring method

Mode for Carrying Out the Invention

[0024] Hereinafter, referring to the attached drawings, the configuration and operation of specific embodiments of the present invention will be described in detail Here, when assigning reference numerals to the components of each drawing, it should be noted that, for identical components, the same numeral should be used as much as possible, even if they appear on other drawings.

[0025] Figure 2 is a schematic diagram showing an in-line film manufacturing process to which the film temperature and thickness measuring device according to the present invention is applied, and Figure 3 is a schematic configuration diagram of the film temperature and thickness measuring device according to the present invention.

[0026] Referring to Figures 2 and 3, a preferred embodiment of the present invention, the film temperature and thickness measuring device 100, may include a transport unit 110, a thickness measuring unit 120, a temperature measuring unit 130, and a control unit 140.

[0027] For reference, and for the sake of explanation, an example of measuring the temperature and thickness of a film 1 extruded by an extruder 10 using the film temperature and thickness measuring device 100 according to the present invention will be illustrated and explained below. Of course, it is not limited to this, and the measuring device 100 according to the present invention can also be applied to measure the temperature and thickness of the film 1 with the coating layer formed during the manufacturing process of a film 1 in which a coating slurry is applied to a substrate to form a coating layer (WET coating).

[0028] The configuration of this invention will be explained in detail as follows. First, the transport unit 110 transports the polymer film 1 (hereinafter abbreviated as "film") extruded from the extruder 10 in one direction. Such a transport unit 110 employs an in-line system with a roll-to-roll structure, enabling the continuous production of the film 1.

[0029] Specifically, the transport unit 110 may include a plurality of rotating rolls 111 that receive power from a motor and transport the film 1 while rotating at a predetermined speed. In this case, the film temperature and thickness measuring device 100 according to the present invention is provided on one of the multiple rotating rolls 111.

[0030] Referring to Figures 4 and 5, the thickness measuring unit 120 is provided at a predetermined distance from the outer surface of the rotating roll 111, and the thickness of the conveyed film 1 can be measured in real time.

[0031] Specifically, the thickness measuring unit 120 may include a guide rail 121 spaced parallel to the central axis of the rotating roll 111, a movable plate 123 connected to the guide rail 121 so as to be reciprocally movable by receiving power along the longitudinal direction of the guide rail 121, and a laser displacement sensor 127 connected to the movable plate 123 via a first bracket 125, which measures the thickness of the film 1 by irradiating a laser toward the surface of the film 1 being conveyed by the rotating roll 111.

[0032] Referring to Figure 6, the movable plate 123 is coupled to the guide rail 121 so as to be able to reciprocate in a direction intersecting the longitudinal direction, thereby adjusting the distance from the outer surface of the rotating roll 111. In this case, the distance of the movable plate 123 can be automatically adjusted by power or manually adjusted. In this invention, the case in which the distance of the movable plate 123 is manually adjusted is given as an example.

[0033] Referring to Figure 7, the first bracket 125 is coupled to the first hinge axis 125a of the movable plate 123 so as to be able to pivot by a predetermined angle along the transport direction of the film 1 with the first hinge axis 125a of the movable plate 123 as the center of rotation. This allows adjustment of the laser irradiation angle of the laser displacement sensor 127 that is irradiated toward the surface of the film 1.

[0034] In this case, the structure that slides the laser displacement sensor 127 in the longitudinal direction of the film 1 or in a direction intersecting the longitudinal direction can be constructed by selectively applying a variety of conventionally known components, so a detailed explanation of this structure will be omitted.

[0035] Referring to Figure 8, the principle of measuring the thickness of the film 1 using the thickness measuring unit 120 configured as described above is as follows: First, the laser displacement sensor 127 is used to irradiate the surface of the rotating roll 111, which is not being transported with the film 1, with a laser, and the outer diameter d of the rotating roll 111 is measured by the distance from the surface of the rotating roll 111, and this is set as the base value. For reference, the roundness of the rotating roll 111 can be used as the base value. Subsequently, when the film 1 is being transported using the rotating roll 111, the laser displacement sensor 127 is used to irradiate the surface of the film 1 with a laser, and the distance measurement from the film 1 is taken. Then, by subtracting the base value from the measurement of the distance from the surface of the film 1 measured by the laser displacement sensor 127, the thickness t of the film 1 can be derived.

[0036] Referring again to Figure 6, the temperature measuring unit 130 is positioned adjacent to the thickness measuring unit 120, and can measure the surface temperature of the conveyed film 1 in real time.

[0037] Referring specifically to Figure 9, the temperature measuring unit 130 may include a second bracket 131 that is coupled to the first bracket 125 so as to be able to move back and forth along a direction intersecting the longitudinal direction of the rotating roll 111 (the conveying direction of the film 1), and an infrared temperature sensor 133 provided on the second bracket 131 for measuring the surface temperature of the film 1 conveyed by the rotating roll 111.

[0038] In this case, the infrared temperature sensor 133 is coupled to the second hinge axis 131a of the second bracket 131 so as to be able to pivot by a predetermined angle along the transport direction of the film 1 with the second hinge axis 131a of the second bracket 131 as the center of rotation. This allows the infrared irradiation position of the infrared temperature sensor 133 to be adjusted. The temperature and thickness measuring device 100, which is equipped with the temperature measuring unit 130 and the thickness measuring unit 120 as described above, is preferably installed on the first rotating roll 111 (see Figure 2) among the plurality of rotating rolls 111 that is located in the direction of film transport of the film 1.

[0039] In other words, after the film 1 is extruded, it can shrink or expand due to heat during the process of being transported by the multiple rotating rolls 111. Therefore, accurate measurement data can be obtained by measuring the temperature and thickness of the film 1 immediately after extrusion molding, before the film 1 shrinks and expands during the transport process.

[0040] However, in this invention, the temperature / thickness measurement position of the film 1 using the measuring device 100 is not particularly limited. That is, the measuring device 100 may be applied to the first rotating roll (chill or cooling roll) immediately after the extrusion process of the film 1, or to the second or third rotating roll, or to the rotating roll after the stretching process in the width direction or longitudinal direction of the film.

[0041] In this case, the temperature measuring unit 130 and the thickness measuring unit 120 are arranged on the same line as the conveying direction of the film 1 so that the temperature and thickness of the film 1 at the same point on the conveyed film 1 can be measured sequentially. Of course, this is not the only option, and the temperature measuring unit 130 and the thickness measuring unit 120 can also be arranged close to each other in the width direction of the conveyed film 1 to measure the temperature and thickness at nearby locations. In the present invention, an example in which the temperature measuring unit 130 and the thickness measuring unit 120 are arranged on the same line as the conveyed film 1 is illustrated and explained.

[0042] Referring to Figure 10, when the film 1 is extruded, the measurement positions L of the temperature measurement unit 130 and the thickness measurement unit 120 are preferably within 0 to 30 mm, more preferably within 0 to 10 mm, along the transport direction of the film 1, and are preferably measured sequentially at the same nearby positions. That is, if the measurement positions L of the temperature measurement unit 130 and the thickness measurement unit 120 exceed 30 mm, errors may occur due to temperature changes after film extrusion.

[0043] Furthermore, when the film 1 is coated and molded, it is preferable that the measurement positions L of the temperature measuring section 130 and the thickness measuring section 120 measure at close proximity within 0 to 100 mm along the transport direction of the film 1. That is, when the film 1 is coated and molded, the film 1 is transported at a faster transport speed than in extrusion molding. This allows the range of the measurement positions L to increase in proportion to the speed. Referring to Figure 11, multiple temperature measuring units 130 and thickness measuring units 120 with the structure described above are spaced apart along the longitudinal direction of the guide rail 121, allowing for sequential measurement of the temperature and thickness of multiple points on the film 1.

[0044] In this case, the present invention illustrates and explains an example in which the temperature of a predetermined point on the extruded film 1 is measured first, and then the thickness of the film 1 is measured at the same point. However, the invention is not limited to this example, and can be modified to measure the thickness of the extruded film 1 first, and then the temperature of the film 1.

[0045] In other words, with reference to the upstream to downstream direction of the conveying direction of the film 1 being extruded by the rotating roll 111, a thickness measuring section 120 is formed on the upstream side and a temperature measuring section 130 is formed on the downstream side. Alternatively, with reference to the upstream to downstream direction of the conveying direction of the film 1 being extruded by the rotating roll 111, a temperature measuring section 130 may be formed on the upstream side and a temperature measuring section 120 may be formed on the upstream side.

[0046] On the other hand, the control unit 140 (see Figure 3) can determine whether the measured values ​​obtained by the thickness measuring unit 120 and the temperature measuring unit 130, respectively, exceed a reference value.

[0047] In other words, the control unit 140 can change the conditions of the film manufacturing process for extruded film 1 based on the thickness and temperature measurements of the film 1 by the thickness measuring unit 120 and the temperature measuring unit 130, thereby producing a film 1 of uniform thickness.

[0048] As an example, the control unit 140 can heat-treat the film 1 after extrusion molding by stretching and heat-setting to remove localized twists and other distortions that occurred during molding. This suppresses shrinkage and wrinkling of the film 1 and improves dimensional stability, such as maintaining a uniform thickness of the film 1.

[0049] The process of measuring film temperature and thickness using the film temperature and thickness measuring device 100 of the present invention will be described below with reference to Figure 12. First, the film is extruded using the extruder 10 (S1). Subsequently, the film to be extruded is conveyed in one direction by the rotating roll 111 (S2). Subsequently, after the film 1 is extruded, infrared rays are irradiated from the conveying rotating roll 111 toward a predetermined point on the surface of the film 1 to measure the temperature of the film 1 (S3).

[0050] Along with this, the same point on the film 1 where the temperature was measured is irradiated with a laser to measure the thickness of the film 1 (S4). In this case, although the present invention has described measuring the temperature of the film 1 first (S3) and then measuring the thickness of the film 1 (S4), it is possible to change this to measuring the thickness of the film 1 first (S3') and then irradiating infrared light toward the same point on the film 1 where the thickness of the film 1 was measured to measure the temperature of the film 1 (S4').

[0051] In other words, to sequentially measure the surface temperature and thickness of the film 1 at the same point on the conveyed film 1, the temperature of the film 1 can be measured first along the same line as the conveying direction of the film 1, and then the thickness of the film 1 can be measured. Alternatively, to sequentially measure the thickness and surface temperature of the film 1 at the same point on the conveyed film 1, the thickness of the film 1 can be measured first along the same line as the conveying direction of the film 1, and then the temperature of the film 1 can be measured.

[0052] Then, the control unit 140 compares and determines whether the measured temperature and thickness values ​​of the film 1 exceed the reference values ​​(S5), and if the measured values ​​exceed the reference values, it changes the conditions of the film 1 manufacturing process (S6).

[0053] As shown in Figure 13, the film temperature and thickness measuring device 100 according to the present invention, having the configuration described above, sequentially measures the surface temperature and thickness of the film 1 being formed in-line at the same point, and compares the measured values ​​with reference values ​​in real time, thereby predicting temperature changes and material changes of the film in advance. Based on this, it is possible to change the conditions of the film manufacturing process or to manufacture a film of uniform thickness by going through processes such as heat setting.

[0054] In particular, the present invention allows for the sequential measurement of the temperature and thickness of the film 1 in real time during the extrusion or coating process of the film 1, thereby eliminating the need for the conventional process of measuring samples of the film product and shortening the time required for the manufacturing process.

[0055] Although the present invention has been illustrated and described above with reference to specific embodiments, the present invention is not limited to the above embodiments, and various changes and modifications are possible without departing from the technical concept of the present invention. [Explanation of symbols]

[0056] 1: Film, 100: Temperature and thickness measuring device 110: Conveying section, 111: Rotating roll 120: Thickness measuring section, 121: Guide rail 123: Mobile plate, 125: First bracket 125a: First hinge axis, 127: Laser displacement sensor 130: Temperature measuring unit, 131: Second bracket 131a: Second hinge axis, 133: Infrared temperature sensor 140: Control Unit

Claims

1. In a measuring device for measuring the temperature and thickness of a film to be extruded or coated, A conveying unit is provided with a rotating roll that conveys the film to be molded in one direction, A thickness measuring unit is installed at a distance from the outer surface of the rotating roll to measure the thickness of the film being conveyed, A temperature measuring unit is positioned adjacent to the thickness measuring unit and measures the surface temperature of the film being transported, The system includes a control unit that determines whether the measured values ​​obtained by the thickness measuring unit and the temperature measuring unit, respectively, exceed a reference value, The temperature measuring unit and the thickness measuring unit are, A film temperature and thickness measuring device, positioned on the same line as the film transport direction, so that the surface temperature and thickness of the film can be sequentially measured at the same point on the transported film.

2. The film temperature and thickness measuring device according to claim 1, wherein a thickness measuring unit and a temperature measuring unit are arranged in order from upstream to downstream in the film transport direction.

3. The film temperature and thickness measuring device according to claim 1, wherein a temperature measuring unit and a thickness measuring unit are arranged in order from upstream to downstream in the film transport direction.

4. The aforementioned thickness measuring unit is A guide rail is positioned parallel to the central axis of the rotating roll and spaced apart from it, A movable plate is connected to the guide rail so as to be able to reciprocate by receiving power along the longitudinal direction of the guide rail, A film temperature and thickness measuring device according to claim 1, comprising: a laser displacement sensor coupled to the moving plate via a first bracket and irradiating a laser toward the surface of a film conveyed by the rotating roll to measure the thickness of the film.

5. The aforementioned movable plate is The film temperature and thickness measuring device according to claim 4, further comprising being coupled so as to be reciprocally movable in a direction intersecting the longitudinal direction of the guide rail, and allowing adjustment of the distance from the outer circumferential surface of the rotating roll.

6. The first bracket is, The film temperature and thickness measuring device according to claim 4, further comprising the fact that the first hinge axis of the movable plate is coupled so as to be able to rotate by a predetermined angle along the film transport direction with respect to the pivot axis of the movable plate, thereby allowing adjustment of the laser irradiation angle of the laser displacement sensor.

7. The aforementioned temperature measuring unit is A second bracket is coupled to the first bracket so as to be able to move back and forth along a direction intersecting the longitudinal direction of the rotating roll, The film temperature and thickness measuring device according to claim 4, further comprising: an infrared temperature sensor provided on the second bracket for measuring the surface temperature of a film conveyed by the rotating roll.

8. The aforementioned infrared temperature sensor is The film temperature and thickness measuring device according to claim 7, further comprising the second hinge axis of the second bracket being coupled so as to be able to pivot by a predetermined angle along the film transport direction with respect to the second hinge axis of the second bracket as the center of rotation, thereby allowing adjustment of the infrared irradiation position of the infrared temperature sensor.

9. The temperature measuring unit and the thickness measuring unit are, The film temperature and thickness measuring device according to claim 1, wherein when the film is extruded, it measures a proximity position within 0 to 30 mm along the conveying direction of the film.

10. The temperature measuring unit and the thickness measuring unit are, The film temperature and thickness measuring device according to claim 1, wherein when the film is coated and molded, it measures a proximity position within 0 to 100 mm along the transport direction of the film.

11. A step of forming a film by an extrusion or coating process, The steps include transporting the film to be formed in one direction by a rotating roll, The steps include: irradiating infrared rays toward the surface of the film being conveyed by the rotating roll to measure the film temperature at a predetermined point; The steps include: measuring the thickness of the film by irradiating a laser onto the same or nearby location on the surface of the film whose temperature has been measured; A step of determining whether the temperature and thickness measurements of the film exceed a reference value, The step of changing the conditions of the film manufacturing process if the measured value exceeds a reference value is also included. The measurement of the temperature and thickness of the aforementioned film is performed. A method for measuring film temperature and thickness, characterized in that it is performed sequentially at the same point on the conveyed film, and along the same line as the conveying direction of the film, by measuring the film temperature followed by the thickness, or by measuring the film thickness followed by the temperature.

12. The step of measuring the thickness of the film is: The steps include: using a laser displacement sensor to irradiate the surface of the rotating roll with a laser while the film is not being transported, measuring the outer diameter of the rotating roll, and setting this as a baseline value; During the transport of the film using the aforementioned rotating roll, the laser displacement sensor irradiates the surface of the film with a laser to measure the distance measurement from the film. A method for measuring the temperature and thickness of a film according to claim 11, comprising the step of deriving the thickness of the film by subtracting a base value from a distance measurement to the film.

Images