Measurement device and measurement method

Abstract

To accurately and efficiently obtain information indicating a bubble state formed during inflation molding.SOLUTION: A measurement device 11 comprises: a galvanomirror 112 which is disposed on an inner surface of a cylindrical molten resin bubble 200 whose shape varies over time; and a sensor 111 which transmits and receives laser light for measuring information indicating the state of the bubble 200 from the inner surface of bubble 200 through the galvanomirror 112.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a measurement device and a measurement method. [Background technology]

[0002] Molding techniques such as inflation molding, which involve solidifying a cylindrical molten resin whose shape changes over time, are known. For example, in inflation molding, air is blown into the inner surface of the molten resin extruded into a cylindrical shape from a die, forming a thin cylindrical molten resin called a bubble. Cooling air is then blown onto the bubbles as they are fed forward, solidifying them to form a resin film. The molding state in inflation molding is managed based on the results of measuring the film thickness using a film thickness measuring device (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-156852 Summary of the Invention [Problem to be solved by the invention]

[0004] In inflation molding, controlling the molding state based on the state of the bubbles at the bubble stage, rather than tracking the thickness of the film after the bubbles formed during molding have been cooled and solidified, allows for more accurate control of the molding state and is also preferable from the viewpoint of increasing yield. The same applies when solidifying a cylindrical molten resin using a molding method other than inflation molding. Therefore, it is desirable to be able to efficiently obtain information indicating the state of the cylindrical molten resin. An object of the present invention is to efficiently obtain information indicating the state of a cylindrical molten resin whose shape changes over time as it is formed during molding. [Means for solving the problem]

[0005] The present invention, which was completed with this objective in mind, is a measuring device characterized by having a mirror placed on at least one of the inner and outer surfaces of a cylindrical molten resin whose shape changes over time, and a sensor that emits and receives light to measure information indicating the state of the molten resin via the mirror from the inner or outer surface of the molten resin. Here, the mirror may be disposed on the inner surface side of the molten resin, and the sensor may transmit and receive the light via the mirror on the inner surface side of the molten resin. The mirror may be a galvanometer mirror that is rotatable about a rotation axis in a predetermined direction relative to the molten resin. The mirror may be a plurality of half mirrors arranged at intervals in the axial direction of the molten resin. The mirror may be a cone mirror that is movable in the axial direction of the molten resin. The mirror may be disposed on the inner surface side of the molten resin, and the sensor may transmit and receive the light from the outer surface side of the molten resin via the mirror. In addition, the mirror may be further arranged on the outer surface side of the molten resin, and the sensor may transmit and receive the light from the outer surface side of the molten resin via the mirrors arranged on each of the outer and inner surfaces of the molten resin. The mirror may be disposed on the outer surface side of the molten resin, and the sensor may transmit and receive the light from the outer surface side of the molten resin via the mirror. The mirrors may be disposed on the inner and outer surfaces of the molten resin, and the sensor may transmit and receive the light from the inner and outer surfaces of the molten resin via the mirrors. Furthermore, as the information indicating the state of the molten resin, at least one of the shape, film thickness, and temperature of the molten resin may be measured. Furthermore, the present invention, which was completed with this object in mind, is a measurement method characterized by including the steps of placing a mirror on at least one of the inner and outer surfaces of a cylindrical molten resin whose shape changes over time, and transmitting and receiving light from a sensor that measures information indicating the state of the molten resin via the mirror from the inner or outer surface of the molten resin. [Effects of the Invention]

[0006] According to the present invention, it is possible to efficiently obtain information indicating the state of a cylindrical molten resin whose shape changes over time as it is formed during molding. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 illustrates an example of a configuration of a measurement apparatus according to a first embodiment. [Figure 2] FIG. 2 is a diagram illustrating a specific example of the configuration of a measurement apparatus that is a first modified example of the first embodiment. [Figure 3] FIG. 10 is a diagram illustrating a specific example of the configuration of a measurement apparatus that is a second modified example of the first embodiment. [Figure 4] FIG. 10 illustrates an example of a configuration of a measurement apparatus according to a second embodiment. [Figure 5] FIG. 10 illustrates an example of a configuration of a measurement apparatus according to a third embodiment. [Figure 6] FIG. 10 illustrates an example of a configuration of a measurement apparatus according to a fourth embodiment. [Figure 7] FIG. 10 illustrates an example of the configuration of a measurement apparatus according to a fifth embodiment. [Figure 8] 10A to 10C are diagrams showing specific examples of mirrors used to measure information indicating the state of a bubble. [Figure 9] FIG. 13 illustrates an example of the configuration of a measurement apparatus according to a sixth embodiment. [Figure 10] FIG. 13 illustrates an example of the configuration of a measurement apparatus according to a seventh embodiment. [Figure 11] FIG. 13 is a diagram illustrating a specific example of the configuration of a measurement device that is a modified example of the seventh embodiment. [Figure 12] FIG. 13 illustrates an example of the configuration of a measurement apparatus according to an eighth embodiment. [Figure 13] (A) is a diagram showing an example of a bubble abnormality, while (B) and (C) are diagrams showing examples of measuring the state of a bubble using only a sensor without using a mirror. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First Embodiment FIG. 1 is a diagram showing an example of the configuration of a measurement device 11 according to the first embodiment. 1 is a device applied to the inflation molding apparatus 10, and is capable of measuring information indicating the state at a certain timing of a thin-film cylindrical bubble 200, which is an example of a cylindrical molten resin whose shape changes over time, formed by the inflation molding apparatus 10. The inflation molding apparatus 10 is a device that forms a resin film as a product by inflation molding.

[0009] The inflation molding apparatus 10 heats the resin to make it molten, then extrudes the molten resin from an annular die (not shown), which is a nozzle, and blows air into the inner surface of the cylindrical molten resin. As a result, the molten resin expands, forming a bubble 200 of thin, cylindrical molten resin, as shown in Figure 1. The inflation molding apparatus 10 applies cooling air to the formed bubble 200 to solidify it, thereby molding a resin film as a product.

[0010] The bubble 200 formed during molding in the inflation molding apparatus 10 is cooled and gradually solidified as it is fed in the axial direction from the bottom to the top of the drawing. For this reason, the bubble 200 shown in FIG. 1 is closer to the die at the bottom than at the top, and is therefore at a higher temperature. In other words, the state of the bubble 200 shown in FIG. 1 is not yet in the state of a film product, but is in the middle of molding, gradually solidifying as it is cooled. Hereinafter, the axial direction of the bubble 200 will be referred to as the "vertical direction," the bottom side of the drawing will be referred to as the "bottom side" of the vertical direction, and the top side of the drawing will be referred to as the "top side" of the vertical direction.

[0011] Measuring device 11 includes one sensor 111 and one galvanometer mirror 112, and is capable of measuring information indicating the state of bubble 200 at a certain timing as it is fed forward. Specifically, measuring device 11 is capable of measuring the distance from sensor 111 to bubble 200 via galvanometer mirror 112 (hereinafter referred to as the "measurement target distance") as information indicating the state of bubble 200 at a certain timing.

[0012] Sensor 111 is a sensor capable of measuring distance, and in this embodiment is configured as a so-called time-of-flight laser distance sensor that converts the time from transmission to reception of laser light into distance. The installation position of sensor 111 is not particularly limited, but in the first embodiment, sensor 111 is installed near the axis on the inner radial side of bubble 200.

[0013] Galvanometer mirror 112 is a mirror installed so as to be rotatable around the radial direction of bubble 200 as a rotation axis. Galvanometer mirror 112 assists the measurement of sensor 111 by reflecting laser light emitted and received by sensor 111. The installation position of galvanometer mirror 112 is not particularly limited, but in the first embodiment, galvanometer mirror 112 is installed near the axis on the inner side in the radial direction of bubble 200.

[0014] There are no particular limitations on the method for installing sensor 111 and galvanometer mirror 112. For example, structure 300 extending in the vertical direction may be installed near the radially inner axis of bubble 200, and sensor 111 and galvanometer mirror 112 may be installed on structure 300. There are no particular limitations on structure 300, and it may be, for example, a cooling tower used to cool bubble 200.

[0015] Sensor 111 in FIG. 1 is disposed on the bottom side of galvanometer mirror 112. Sensor 111 transmits and receives laser light via galvanometer mirror 112 to measure the target distance of bubble 200 at a certain timing. Specifically, the laser light transmitted from sensor 111 is reflected by galvanometer mirror 112, which rotates at high speed, and reflected by regions to be measured (hereinafter referred to as "target measurement regions") 201 and 202 indicated by dashed lines on bubble 200, which is the target of measurement, before being reflected again by galvanometer mirror 112 and received by sensor 111. Note that the target measurement region indicated by dashed lines is a visual representation of the region that may be the target of measurement, and may be larger than the dashed line region shown in FIG. 1.

[0016] Sensor 111 measures the target distance by converting the time from emission to reception of the laser light into a distance. In the example of FIG. 1 , the laser light emitted from sensor 111 toward the top and bottom is reflected by galvanometer mirror 112, which rotates at high speed, toward measurement target area 201 or measurement target area 202 of bubble 200. The laser light reflected toward measurement target area 201 is reflected by measurement target area 201, then reflected again by galvanometer mirror 112, and received by sensor 111. The laser light reflected toward measurement target area 202 is reflected by measurement target area 202, then reflected again by galvanometer mirror 112, and received by sensor 111. This makes it possible to determine the shape of bubble 200 based on the target distances to measurement target areas 201 and 202 of bubble 200 at a certain timing.

[0017] (Variation 1) FIG. 2 is a diagram showing a specific example of the configuration of a measurement device 12 according to a first modified example of the first embodiment. The measuring device 12 shown in Figure 2 is a device that is applied to the inflation molding apparatus 10, similar to the measuring device 11 in Figure 1 described above, and is a device that can measure information indicating the state of the bubble 200 formed by the inflation molding apparatus 10.

[0018] Measurement device 12 includes one transmitting sensor 113, one transmitting sensor 114, one galvanometer mirror 112, and one reflecting mirror 115, and is capable of measuring information indicating the state at a certain timing of bubble 200 being sent forward. Specifically, measurement device 12 is capable of measuring a measurement target distance as information indicating the state at a certain timing of bubble 200.

[0019] Sensors 113 and 114 are a pair of laser distance sensors that share the functions of transmission and reception. Sensor 113, like sensor 111 of measuring device 11 in FIG. 1 described above, is installed on the inner surface of bubble 200, near the radially inner axis of bubble 200. In contrast, sensor 114 is installed on the outer surface of bubble 200. In other words, variant 1 is an example in which the sensors used to measure the target distance are divided into a transmission side and a reception side.

[0020] The galvanometer mirror 112 of the measurement device 12 shown in Fig. 2 is a galvanometer mirror having the same configuration as the galvanometer mirror 112 of the measurement device 11 described above in Fig. 1. That is, the galvanometer mirror 112 is a galvanometer mirror that is installed near the inner axis of the bubble 200 in the radial direction so as to be rotatable around the radial direction of the bubble 200 as the rotation axis.

[0021] 1 described above, is a mirror configured to transmit laser light from sensor 113 located on the bottom side of itself in the vertical direction and to reflect laser light from galvanometer mirror 112 located on the top side of itself in the vertical direction. Folding mirror 115 is installed near the inner axis of bubble 200 in the radial direction, at the same or approximately the same height as sensor 114 in the vertical direction. The orientation of folding mirror 115 is adjusted so that the reflected laser light is received by sensor 114.

[0022] 2, laser light emitted from sensor 113 toward the top in the vertical direction passes through reflecting mirror 115 and is reflected by galvanometer mirror 112, which rotates at high speed, toward measurement target area 203 or measurement target area 204 of bubble 200. The laser light reflected toward measurement target area 203 is reflected by measurement target area 203, then reflected again by galvanometer mirror 112 and reflecting mirror 115, and received by sensor 114. The laser light reflected toward measurement target area 204 is reflected by measurement target area 204, then reflected again by galvanometer mirror 112 and reflecting mirror 115, and received by sensor 114. This makes it possible to determine the shape of bubble 200 based on the measurement target distances to measurement target areas 203 and 204 at a certain timing.

[0023] (Variation 2) Fig. 3 is a diagram showing a specific example of the configuration of the measuring device 13, which is a second modified example of the first embodiment. Fig. 3 shows the measuring device 13 as viewed from the top to the bottom in the vertical direction of the bubble 200. The measuring device 13 shown in Figure 3 is a device that is applied to the inflation molding apparatus 10, similar to the measuring device 11 in Figure 1 described above, and is a device that can measure information indicating the state of the bubble 200 formed by the inflation molding apparatus 10.

[0024] Measuring device 13 includes one sensor 111 and one galvanometer mirror 116, and is capable of measuring information indicating the state at a certain timing of bubble 200 being fed forward. Specifically, measuring device 13 is capable of measuring a measurement target distance as information indicating the state at a certain timing of bubble 200.

[0025] Sensor 111 of measuring device 13 in Fig. 3 is a laser distance sensor having a configuration similar to that of sensor 111 of measuring device 11 in Fig. 1. Unlike galvanometer mirror 112 in Fig. 1, galvanometer mirror 116 is a mirror installed so as to be rotatable around the axis of rotation that is the up-and-down direction of bubble 200.

[0026] 3, laser light emitted from sensor 111 toward the approximate ceiling in the vertical direction (from the back to the front of the drawing) is reflected by galvanometer mirror 116, which rotates at high speed, reflected by measurement target area 205 of bubble 200, and then reflected again by galvanometer mirror 116 and received by sensor 111. This makes it possible to grasp the shape of bubble 200 based on the measurement target distance at a certain timing in measurement target area 205.

[0027] Here, measurement target areas 201 and 202 of bubble 200 in Fig. 1 are compared with measurement target area 205 of bubble 200 in Fig. 3. In measurement target areas 201 and 202 in Fig. 1, the collection of measurement points of bubble 200 extends in the vertical direction of bubble 200, forming two straight lines. In contrast, in measurement target area 205 in Fig. 3, the collection of measurement points of bubble 200 extends in the circumferential direction of bubble 200, forming a ring shape.

[0028] 1, by combining sensor 111 with galvanometer mirror 112 that rotates at high speed around the radial direction of bubble 200 as its rotation axis, it is possible to simultaneously or approximately simultaneously measure the distance to measurement target areas 201 and 202. As a result, it is possible to grasp the shape of bubble 200 in the vertical direction at a certain timing. In contrast, measurement device 13 in FIG. 3, by combining sensor 111 with galvanometer mirror 116 that rotates at high speed around the vertical direction of bubble 200 as its rotation axis, it is possible to simultaneously or approximately simultaneously measure the distance to measurement target area 205. As a result, it is possible to grasp the shape of bubble 200 in the circumferential direction at a certain timing.

[0029] In summary, the measuring device 11 according to the first embodiment of the present invention only needs to have the following configuration, and can take on a variety of different embodiments. That is, the measuring device 11 is characterized by having a galvanometer mirror 112 (or galvanometer mirror 116) arranged on the inner surface of a thin-film cylindrical bubble 200, which is an example of a cylindrical molten resin whose shape changes over time, and a sensor 111 that emits and receives laser light to measure information indicating the state of the bubble 200 from the inner surface of the bubble 200 via the galvanometer mirror 112 (or galvanometer mirror 116).

[0030] This allows the combination of galvanometer mirror 112 (or galvanometer mirror 116) and sensor 111, both of which are arranged on the inner surface side of bubble 200, to measure a measurement target distance that indicates the state of measurement target areas 201 and 202 (or measurement target areas 203 and 204) at a certain timing. As a result, information indicating the shape of bubble 200 as information indicating the state of bubble 200 at a certain timing can be efficiently obtained. For example, it also becomes possible to grasp the shape of bubble 200 at a certain timing in three dimensions.

[0031] Here, the mirror arranged on the inner surface side of the bubble 200 may be the galvanometer mirror 112 or the galvanometer mirror 116 that is rotatable with a predetermined direction relative to the bubble 200 as the rotation axis. As a result, for example, by combining galvanometer mirror 112, which can rotate around the radial direction of bubble 200 as its rotation axis, with sensor 111, it becomes possible to measure a measurement target distance that indicates the state of measurement target areas 201 and 202 at a certain timing. Also, by combining galvanometer mirror 116, which can rotate around the axial direction of bubble 200 as its rotation axis, with sensor 111, it becomes possible to measure a measurement target distance that indicates the state of measurement target area 205 at a certain timing.

[0032] Furthermore, as information indicating the state of the bubble 200, at least one of the shape, film thickness, and temperature of the bubble 200 may be measured. This makes it possible to efficiently obtain information indicating at least one of the shape, film thickness, and temperature of the bubble 200 as information indicating the state of the bubble 200 at a certain timing.

[0033] The measurement method according to this embodiment only needs to have the following configuration, and can take various forms. In other words, the measurement method of this embodiment is characterized by including the steps of placing a galvanometer mirror 112 (or a galvanometer mirror 116) on the inner surface of a thin-film cylindrical bubble 200, which is an example of a cylindrical molten resin whose shape changes over time, and transmitting and receiving laser light from a sensor 111 that measures information indicating the state of the bubble 200 from the inner surface of the bubble 200 via the galvanometer mirror 112 (or a galvanometer mirror 116).

[0034] This makes it possible to measure the measurement target distance, which indicates the state of measurement target areas 201 and 202 (or measurement target areas 203 and 204) at a certain timing, by combining galvanometer mirror 112 (or galvanometer mirror 116) and sensor 111, which are arranged on the inner surface side of bubble 200. As a result, information indicating the shape of bubble 200 as information indicating the state at a certain timing can be efficiently obtained.

[0035] <Second embodiment> FIG. 4 is a diagram showing an example of the configuration of a measuring device 21 according to the second embodiment. The measuring device 21 shown in FIG. 4 is a device that is applied to the inflation molding device 20, and is a device that can measure the state of the bubble 200 formed by the inflation molding device 20.

[0036] Measuring device 21 includes one sensor 211 and one galvanometer mirror 212, and is capable of measuring information indicating the state at a certain timing of bubble 200 being fed forward. Specifically, measuring device 21 is capable of measuring a measurement target distance as information indicating the state at a certain timing of bubble 200.

[0037] The sensor 211 is configured as a so-called time-of-flight laser distance sensor, similar to the first embodiment described above, but the installation location is different. That is, the sensor 111 according to the first embodiment described above is installed on the inner surface side of the bubble 200, whereas the sensor 211 according to the second embodiment is installed on the outer surface side of the bubble 200. The method for installing the sensor 211 is not particularly limited. For example, the sensor 211 may be installed on a structure (not shown) that extends in the vertical direction on the outer surface side of the bubble 200.

[0038] 1 described above, galvanometer mirror 212 is a mirror installed so as to be rotatable around the radial direction of bubble 200 as a rotation axis, and is installed near the inner axis of bubble 200 in the radial direction. The method of installing galvanometer mirror 212 is not particularly limited. As in the first embodiment described above, structure 300 extending in the vertical direction may be installed near the inner axis of bubble 200 in the radial direction, and galvanometer mirror 212 may be installed on structure 300. Furthermore, although not shown, galvanometer mirror 212 may be installed so as to be rotatable around the vertical direction of bubble 200 as a rotation axis, similar to galvanometer mirror 116 described above in FIG. 3.

[0039] 4 is disposed at the same or approximately the same height in the vertical direction as the galvanometer mirror 212. The sensor 211 transmits and receives laser light for measuring the state of the bubble 200 via the galvanometer mirror 212.

[0040] 4, laser light emitted from sensor 211 passes through measurement target area 206 of bubble 200 and is reflected by galvanometer mirror 212, which rotates at high speed, toward measurement target area 206 or measurement target area 207 of bubble 200. The laser light reflected toward measurement target area 206 is reflected at measurement target area 206, reflected again by galvanometer mirror 212, passes through measurement target area 206, and is received by sensor 211. The laser light reflected toward measurement target area 207 is reflected at measurement target area 207, reflected again by galvanometer mirror 212, passes through measurement target area 206, and is received by sensor 211.

[0041] This allows the measurement target distance at a certain timing to be measured for measurement target areas 206 and 207. As a result, it becomes possible to grasp the shape of bubble 200 based on the measurement target distance measured by sensor 211. Specifically, it becomes possible to grasp the shape of each of measurement target areas 206 and 207 of bubble 200.

[0042] In summary, the measuring device 21 according to the second embodiment of the present invention only needs to have the following configuration, and can take on a variety of different embodiments. That is, measuring device 21 is characterized by having a galvanometer mirror 212 arranged on the outer surface side of a thin-film cylindrical bubble 200, which is an example of a cylindrical molten resin whose shape changes over time, and a sensor 211 that emits and receives laser light from the outer surface side of bubble 200 via galvanometer mirror 212 to measure information indicating the state of bubble 200. This makes it possible to measure the measurement target distance, which indicates the state of the measurement target areas 206 and 207 at a certain time, by combining the galvanometer mirror 212 arranged on the inner side of the bubble 200 and the sensor 211 arranged on the outer side of the bubble 200.

[0043] Furthermore, the measurement method using the measurement device 21 according to this embodiment only needs to have the following configuration, and various embodiments can be adopted. In other words, the measurement method using the measuring device 21 is characterized by including the steps of placing a galvanometer mirror 212 on the inner surface of a thin-film cylindrical bubble 200, which is an example of a cylindrical molten resin whose shape changes over time, and transmitting and receiving laser light from a sensor 211 that measures information indicating the state of the bubble 200 from the outer surface side of the bubble 200 via the galvanometer mirror 212.

[0044] This allows the combination of galvanometer mirror 212 arranged on the inner surface side of bubble 200 and sensor 211 arranged on the outer surface side of bubble 200 to measure the measurement target distance that indicates the state at a certain time of measurement target areas 206 and 207. As a result, information indicating the shape as information indicating the state of bubble 200 at a certain time can be efficiently obtained.

[0045] <Third embodiment> FIG. 5 is a diagram showing an example of the configuration of a measuring device 31 according to the third embodiment. The measuring device 31 shown in FIG. 5 is a device that is applied to the inflation molding device 30, and is a device that can measure the state of the bubble 200 formed by the inflation molding device 30.

[0046] Measuring device 31 includes one sensor 311 and two galvanometer mirrors 312 and 313, and is capable of measuring information indicating the state at a certain timing of bubble 200 being fed forward. Specifically, measuring device 31 is capable of measuring a measurement target distance as information indicating the state at a certain timing of bubble 200.

[0047] Sensor 311 is a laser distance sensor installed on the outer surface side of bubble 200, similar to sensor 211 shown in Fig. 4 above. However, unlike sensor 211 in Fig. 4, sensor 311 emits laser light toward galvanometer mirror 312 installed on the outer surface side of bubble 200. Specifically, as shown in Fig. 5, sensor 311 emits laser light in the vertical direction toward galvanometer mirror 312, which is located on the top side of sensor 311 in the vertical direction.

[0048] Galvanometer mirror 312 is a galvanometer mirror installed on the outer surface side of bubble 200 so as to be rotatable around a rotation axis in the vertical direction. Galvanometer mirror 312 is installed on the upper side in the vertical direction with respect to sensor 311. Galvanometer mirror 313 is a galvanometer mirror with a configuration similar to that of galvanometer mirror 112 in FIG. 1 described above. That is, galvanometer mirror 313 is installed near the inner axis of bubble 200 in the radial direction so as to be rotatable around a rotation axis in the radial direction of bubble 200. Galvanometer mirror 313 and galvanometer mirror 312 are installed at the same or approximately the same height in the vertical direction.

[0049] Although not shown, galvanometer mirror 312 may be installed so as to be rotatable around the radial direction as its axis of rotation. Galvanometer mirror 313 may be installed so as to be rotatable around the vertical direction as its axis of rotation. Sensor 311 may be installed on the outer surface of bubble 200, and galvanometer mirrors 312 and 313 may be installed on the inner surface of bubble 200. Furthermore, both sensor 311 and galvanometer mirrors 312 and 313 may be installed on the inner surface of bubble 200. In this case, for example, a unit integrating sensor 311 and galvanometer mirrors 312 and 313 may be installed on the inner surface of bubble 200.

[0050] 5, laser light emitted from sensor 311 is reflected by galvanometer mirror 312 and passes through measurement target area 208 of bubble 200. The laser light that has passed through measurement target area 208 is reflected by galvanometer mirror 313, which rotates at high speed, toward measurement target area 208 or measurement target area 209 of bubble 200.

[0051] The laser light reflected toward the measurement target area 208 is reflected by the measurement target area 208, reflected again by galvanometer mirror 313, and transmitted through the measurement target area 208. The laser light transmitted through the measurement target area 208 is reflected again by galvanometer mirror 312 and received by sensor 311. The laser light reflected toward the measurement target area 209 is reflected by the measurement target area 209, reflected again by galvanometer mirror 313, transmitted through the measurement target area 208, and received by sensor 311. This makes it possible to determine the shape of bubble 200 based on the measurement target distance between measurement target areas 208 and 209 at a certain timing.

[0052] In summary, the measuring device 31 according to the third embodiment of the present invention only needs to have the following configuration, and can take on a variety of different embodiments. That is, measuring device 31 is characterized by having galvanometer mirrors 312 and 313 arranged on at least one of the inner and outer sides of thin-film cylindrical bubble 200, which is an example of a cylindrical molten resin whose shape changes over time, and sensor 311 that emits and receives laser light from the outer side of bubble 200 via galvanometer mirrors 312 and 313 to measure information indicating the state of bubble 200. This makes it possible to measure the measurement target distance, which indicates the state of measurement target areas 208 and 209 at a certain time, by combining galvanometer mirror 312 arranged on the outer surface side of bubble 200, galvanometer mirror 313 arranged on the inner surface side of bubble 200, and sensor 311 arranged on the outer surface side of bubble 200.

[0053] <Fourth embodiment> FIG. 6 is a diagram showing an example of the configuration of a measuring device 41 according to the fourth embodiment. The measuring device 41 shown in FIG. 6 is a device that is applied to the inflation molding device 40, and is a device that can measure the state of the bubble 200 formed by the inflation molding device 40.

[0054] Measuring device 41 includes one sensor 411 and one galvanometer mirror 412, and is capable of measuring information indicating the state at a certain timing of bubble 200 being fed forward. Specifically, measuring device 41 is capable of measuring a measurement target distance as information indicating the state at a certain timing of bubble 200.

[0055] Sensor 411 has the same configuration as sensor 311 shown in Fig. 5 above, and emits laser light from the bottom side in the vertical direction toward galvanometer mirror 412, which is placed on the top side in the vertical direction relative to sensor 411. Galvanometer mirror 412 is installed in the same position as galvanometer mirror 312 in Fig. 5, but differs in that it is rotatable around a rotation axis that is horizontally perpendicular to the radial direction of bubble 200. Although not shown, galvanometer mirror 412 may also be installed so that it is rotatable around a rotation axis that is the top-to-bottom direction.

[0056] 6, laser light emitted from sensor 411 is reflected by galvanometer mirror 412, a portion of which is reflected by measurement target region 210 of bubble 200, and a portion of which passes through measurement target region 210. The laser light reflected by measurement target region 210 is reflected again by galvanometer mirror 412 and received by sensor 411. Furthermore, the laser light that passes through measurement target region 210 is reflected by measurement target region 241 of bubble 200, passes through measurement target region 210 again, and is received by sensor 411. This makes it possible to determine the shape of bubble 200 based on the measurement target distances between measurement target regions 210 and 241 at a certain timing.

[0057] In summary, the measuring device 41 according to the fourth embodiment of the present invention only needs to have the following configuration, and can take on a variety of different embodiments. That is, measuring device 41 is characterized by having a galvanometer mirror 412 arranged on the outer surface side of thin-film cylindrical bubble 200, which is an example of a cylindrical molten resin whose shape changes over time, and sensor 411 that emits and receives laser light from the outer surface side of bubble 200 via galvanometer mirror 412 to measure information indicating the state of bubble 200. As a result, by combining the galvanometer mirror 412 and the sensor 411 arranged on the outer surface side of the bubble 200, it becomes possible to measure the measurement target distance that indicates the state of the measurement target areas 210 and 241 at a certain timing.

[0058] <Fifth embodiment> FIG. 7 is a diagram showing an example of the configuration of a measuring device 51 according to the fifth embodiment. The measuring device 51 shown in FIG. 7 is a device that is applied to the inflation molding device 50, and is a device that can measure information indicating the state of the bubble 200 formed by the inflation molding device 50.

[0059] Measuring device 51 includes three sensors 511 to 513 and three galvanometer mirrors 514 to 516, and is capable of measuring information indicating the state of bubble 200 at a certain time as it is fed forward. Specifically, measuring device 51 is capable of measuring the film thickness as information indicating the state of bubble 200 at a certain time.

[0060] Sensor 511 is a laser distance sensor with a configuration similar to sensor 111 of measurement apparatus 11 in FIG. 1 described above. Sensors 512 and 513 are laser distance sensors with a configuration similar to sensor 411 of measurement apparatus 41 in FIG. 6 described above. Galvanometer mirror 514 is a galvanometer mirror with a configuration similar to galvanometer mirror 112 of measurement apparatus 11 in FIG. 1 described above, and is installed on the inner surface of bubble 200 so as to be rotatable around the radial direction of bubble 200 as its axis of rotation. Galvanometer mirrors 515 and 516 are galvanometer mirrors with a configuration similar to galvanometer mirror 412 of measurement apparatus 41 in FIG. 6 described above. That is, galvanometer mirrors 515 and 516 are galvanometer mirrors installed on the outer surface of bubble 200 so as to be rotatable around the axis of rotation in a direction horizontally perpendicular to the radial direction of bubble 200 as its axis of rotation.

[0061] 7, laser light emitted from sensor 511 is reflected by rapidly rotating galvanometer mirror 514 toward measurement target area 242 or measurement target area 213 of bubble 200. The laser light reflected toward measurement target area 242 is reflected by measurement target area 242, reflected again by galvanometer mirror 514, and received by sensor 511. The laser light reflected toward measurement target area 213 is reflected by measurement target area 213, reflected again by galvanometer mirror 514, and received by sensor 511. This makes it possible to measure the measurement target distances between measurement target areas 242 and 213 at a certain timing.

[0062] Furthermore, the laser light emitted from the sensor 512 is reflected by the galvanometer mirror 515, which rotates at high speed, and is reflected by the measurement target area 242. The laser light reflected by the measurement target area 242 is reflected again by the galvanometer mirror 515 and received by the sensor 512. In this way, the measurement target distance to the measurement target area 242 at a certain timing is measured.

[0063] Furthermore, the laser light emitted from the sensor 513 is reflected by the galvanometer mirror 516, which rotates at high speed, and is reflected by the measurement target area 213. The laser light reflected by the measurement target area 213 is reflected again by the galvanometer mirror 516 and received by the sensor 513. In this way, the measurement target distance to the measurement target area 213 at a certain timing is measured.

[0064] 7, the two mirrors installed on the outer surface of bubble 200 are rotatable galvanometer mirrors 515 and 516, but two non-rotating mirrors that can move in the vertical direction may be installed instead of galvanometer mirrors 515 and 516. In this case, it becomes possible to measure the vertical state of bubble 200 by rotating galvanometer mirror 514.

[0065] Furthermore, although not shown, galvanometer mirror 514 installed on the inner surface of bubble 200 may be installed so as to be rotatable around the vertical direction as the rotation axis. In this case, two non-rotating mirrors that can move in the circumferential direction may be installed instead of galvanometer mirrors 515 and 516 installed on the outer surface of bubble 200. In this case, the radial state of bubble 200 can be measured by rotating galvanometer mirror 514. Note that the method for moving the two non-rotating mirrors installed on the outer surface of bubble 200 in the vertical or circumferential direction is not particularly limited, and for example, a one-axis stage or the like may be used.

[0066] The measurement device 51 having such a configuration makes it possible to determine the film thickness of the bubble 200 based on the measurement target distance measured by the sensors 511 to 513. Specifically, it becomes possible to determine the film thickness in the measurement target region 242 based on the measurement target distance measured at a certain timing by the sensors 511 and 512, and to determine the film thickness in the measurement target region 213 based on the measurement target distance measured at a certain timing by the sensors 511 and 513.

[0067] In summary, the measuring device 51 according to the fifth embodiment of the present invention only needs to have the following configuration, and can take on a variety of different embodiments. That is, the measuring device 51 is characterized by having galvanometer mirrors 514 to 516 arranged on at least one of the inner and outer sides of a thin-film cylindrical bubble 200, which is an example of a cylindrical molten resin whose shape changes over time, and sensors 511 to 513 that emit and receive laser light to measure information indicating the state of the bubble 200 from the inner or outer side of the bubble 200 via the galvanometer mirrors 514 to 516. This makes it possible to measure the film thickness indicating the state of the measurement target areas 242 and 213 at a certain time by combining galvanometer mirrors 514 to 516 arranged on the inner and outer sides of the bubble 200 with sensors 511 to 513 arranged on the inner and outer sides of the bubble 200.

[0068] <Example of a mirror> 8(A) to (C) are diagrams showing specific examples of mirrors used to measure information indicating the state of bubble 200. In Fig. 8, (A) shows a galvanometer mirror, (B) shows a half mirror, and (C) shows a cone mirror, and the arrows indicate the laser light of the laser distance sensor.

[0069] The galvanometer mirror in Fig. 8(A) is a mirror that can reflect the laser light of the laser distance sensor in any direction, and is applied to the first to fifth embodiments as described above. The half mirror in Fig. 8(B) is a mirror that adjusts the reflectance and transmittance of the laser light so that it reflects part of the laser light of the laser distance sensor and transmits part of it, and is applied to the sixth and seventh embodiments described later. The cone mirror in Fig. 8(C) is a cone-shaped mirror that reflects the laser light of the laser distance sensor at multiple angles, and is applied to the eighth embodiment described later.

[0070] Sixth Embodiment FIG. 9 is a diagram showing an example of the configuration of a measuring device 61 according to the sixth embodiment. The measuring device 61 shown in FIG. 9 is a device that is applied to the inflation molding device 60, and is a device that can measure the state of the bubble 200 formed by the inflation molding device 60.

[0071] The measuring device 61 includes two sensors 611 and 612 and six half mirrors 613 to 618, and is capable of measuring information indicating the state of the bubble 200 at a certain timing as it is fed forward. Specifically, the measuring device 61 is capable of measuring the measurement target distance as information indicating the state of the bubble 200 at a certain timing.

[0072] Sensors 611 and 612 are laser distance sensors installed near the radially inner axis of bubble 200 at the same or approximately the same height in the vertical direction of bubble 200. Of three half mirrors 613 to 615 arranged in a row at intervals above sensor 611 in the vertical direction, sensor 611 emits laser light toward half mirror 613 and measures the target distance by receiving the laser light from half mirror 613. Of three half mirrors 616 to 618 arranged in a row at intervals above sensor 611 in the vertical direction, sensor 612 emits laser light toward half mirror 616 and measures the target distance by receiving the laser light from half mirror 616.

[0073] Half mirrors 613 to 618 each reflect a portion of the laser light from the bottom side in the vertical direction toward the outside in the radial direction of bubble 200, and transmit a portion of the laser light toward the top side in the vertical direction. In the example of Figure 9, of the laser light emitted from sensor 611, the laser light reflected by half mirror 613 is reflected at a point to be measured (hereinafter referred to as "measurement point") 214 shown by a dashed line on bubble 200 in Figure 9, and is reflected again by half mirror 613 and received by sensor 611.

[0074] Furthermore, of the laser light emitted from sensor 611, a portion of the laser light that passes through half mirror 613 is reflected by half mirror 614 and a portion of the laser light passes through half mirror 614. Of the laser light that passes through half mirror 613, the laser light reflected by half mirror 614 is reflected at measurement target point 215 and is reflected again by half mirror 614. The laser light reflected by half mirror 614 passes through half mirror 613 from the top to the bottom in the vertical direction and is received by sensor 611.

[0075] Furthermore, at least a portion of the laser light emitted from sensor 611 that passes through half mirrors 613 and 614 is reflected by half mirror 615. The laser light reflected by half mirror 615 is reflected by measurement target point 216 and then reflected by half mirror 615 again. The laser light reflected by half mirror 615 passes through half mirrors 614 and 613 from the top to the bottom in the vertical direction and is received by sensor 611. This makes it possible to grasp the shape of bubble 200 based on the measurement target distances at a certain timing from measurement target points 214 to 216.

[0076] Furthermore, of the laser light emitted from sensor 612, the laser light reflected by half mirror 616 is reflected by measurement target point 217, reflected again by half mirror 616, and received by sensor 612. Of the laser light emitted from sensor 612, the laser light that passes through half mirror 616 is partially reflected by half mirror 617 and partially passes through half mirror 617. Of the laser light that passes through half mirror 616, the laser light reflected by half mirror 617 is reflected by measurement target point 218 and reflected again by half mirror 617. The laser light reflected by half mirror 617 passes through half mirror 616 from the top to the bottom in the vertical direction and is received by sensor 612.

[0077] Furthermore, at least a portion of the laser light emitted from sensor 612 that passes through half mirrors 616 and 617 is reflected by half mirror 618. The laser light reflected by half mirror 618 is reflected by measurement target point 219 and then reflected by half mirror 618 again. The laser light reflected by half mirror 618 passes through half mirrors 617 and 616 from the top to the bottom in the vertical direction and is received by sensor 612. This makes it possible to grasp the shape of bubble 200 based on the measurement target distances at a certain timing from measurement target points 217 to 219.

[0078] There are no particular limitations on the method for installing the sensors 611 and 612 and the half mirrors 613 to 618. For example, a structure 300 extending in the vertical direction may be installed near the radially inner axis of the bubble 200, and the sensors 611 and 612 and the half mirrors 613 to 618 may be installed on the structure 300.

[0079] In summary, the measuring device 61 according to the sixth embodiment of the present invention only needs to have the following configuration, and can take on a variety of different embodiments. That is, measuring device 61 is characterized by having a mirror arranged on the inner surface of thin-film cylindrical bubble 200, which is an example of a cylindrical molten resin whose shape changes over time, and sensors 611 and 612 that emit and receive laser light from the inner surface of bubble 200 via the mirror to measure information indicating the state of bubble 200.

[0080] Here, the mirrors arranged on the inner surface side of the bubble 200 may be a plurality of half mirrors 613 to 618 arranged at intervals in the axial direction of the bubble 200 . This allows measurement of the measurement target distance, which indicates the state of each of the measurement target points 214 to 219 at a certain timing, by combining the half mirrors 613 to 618 arranged on the inner surface of the bubble 200 with the sensors 611 and 612. As a result, information indicating the shape of the bubble 200 can be efficiently obtained as information indicating the state of the bubble 200.

[0081] Seventh embodiment FIG. 10 is a diagram showing an example of the configuration of a measuring device 71 according to the seventh embodiment. A measuring device 71 shown in FIG. 10 is a device that is applied to the inflation molding device 70, and is a device that can measure the state of the bubble 200 formed by the inflation molding device 70.

[0082] Like the measuring device 61 according to the sixth embodiment, the measuring device 71 includes two sensors 711 and 712 and six half mirrors 713 to 718, and is capable of measuring information indicating the state of the bubble 200 at a certain timing as it is fed forward. Specifically, the measuring device 71 is capable of measuring the measurement target distance as information indicating the state of the bubble 200 at a certain timing.

[0083] Sensors 711 and 712 are laser distance sensors installed on the outer surface of bubble 200 at the same or approximately the same height in the vertical direction of bubble 200. Sensor 711 emits laser light toward half mirror 713, one of three half mirrors 713 to 715 arranged in a row at intervals above sensor 711, and measures the target distance by receiving the laser light from half mirror 713. Sensor 712 emits laser light toward half mirror 716, one of three half mirrors 716 to 718 arranged in a row at intervals above sensor 711, and measures the target distance by receiving the laser light from half mirror 716.

[0084] Each of the half mirrors 713 to 718 reflects a portion of the laser light from the bottom side in the top-to-bottom direction toward the inside in the radial direction of the bubble 200, and allows a portion of the laser light to transmit toward the top side in the top-to-bottom direction. In the example of Figure 10, of the laser light emitted from the sensor 711, the laser light reflected by the half mirror 713 is reflected at the measurement target point 220 of the bubble 200 in Figure 10, is reflected again by the half mirror 713, and is received by the sensor 711.

[0085] Furthermore, of the laser light emitted from sensor 711, a portion of the laser light that passes through half mirror 713 is reflected by half mirror 714 and a portion of the laser light passes through half mirror 714. Of the laser light that passes through half mirror 713, the laser light reflected by half mirror 714 is reflected at measurement target point 221 and is reflected again by half mirror 714. The laser light reflected by half mirror 714 passes through half mirror 713 from the top to the bottom in the vertical direction and is received by sensor 711.

[0086] Furthermore, at least a portion of the laser light emitted from sensor 711 that passes through half mirrors 713 and 714 is reflected by half mirror 715. The laser light reflected by half mirror 715 is reflected by measurement target point 222 and then reflected by half mirror 715 again. The laser light reflected by half mirror 715 passes through half mirrors 714 and 713 from the top to the bottom in the vertical direction and is received by sensor 711. This makes it possible to grasp the shape of bubble 200 based on the measurement target distances at a certain timing between measurement target points 220 and 222.

[0087] Furthermore, of the laser light emitted from sensor 712, the laser light reflected by half mirror 716 is reflected by measurement target point 223, reflected again by half mirror 716, and received by sensor 711. Of the laser light emitted from sensor 712, the laser light that passes through half mirror 716 is partially reflected by half mirror 717 and partially passes through half mirror 717. Of the laser light that passes through half mirror 716, the laser light reflected by half mirror 717 is reflected by measurement target point 224 and reflected again by half mirror 717. The laser light reflected by half mirror 717 passes through half mirror 716 from the top to the bottom in the vertical direction and is received by sensor 712.

[0088] Furthermore, at least a portion of the laser light emitted from sensor 712 that passes through half mirrors 716 and 717 is reflected by half mirror 718. The laser light reflected by half mirror 718 is reflected by measurement target point 225 and then reflected by half mirror 718 again. The laser light reflected by half mirror 718 passes through half mirrors 717 and 716 from the top to the bottom in the vertical direction and is received by sensor 712. This makes it possible to grasp the shape of bubble 200 based on the measurement target distances at a certain timing from measurement target points 223 to 225.

[0089] (Variation) FIG. 11 is a diagram showing a specific example of the configuration of a measurement device 72 that is a modified example of the seventh embodiment. The measuring device 72 shown in FIG. 1 is a device that is applied to the inflation molding apparatus 70, similar to the measuring device 71 in FIG. 10 described above, and is a device that can measure information indicating the state of the bubble 200 formed by the inflation molding apparatus 10.

[0090] 10, measuring device 72 includes one sensor 719 and three half mirrors 720 to 722, and is capable of measuring information indicating the state of bubble 200 at a certain timing as it is fed forward. Specifically, measuring device 72 is capable of measuring the measurement target distance as information indicating the state of bubble 200 at a certain timing.

[0091] Sensor 719 is a laser distance sensor installed on the outer surface side of bubble 200. Sensor 719 emits laser light toward half mirror 720, one of three half mirrors 720 to 722 arranged in a row at intervals on the top side of sensor 719 in the vertical direction, and measures the distance to be measured by receiving the laser light from half mirror 720.

[0092] Half mirrors 720 to 722 are mirrors that reflect a portion of the laser light from the bottom side in the vertical direction toward the inside in the radial direction of bubble 200 and allow a portion of the laser light to transmit toward the top side in the vertical direction. In the example of Figure 11, of the laser light emitted from sensor 719, the laser light reflected by half mirror 720 is partially reflected by measurement target point 226 of bubble 200 and partially transmits through measurement target point 226.

[0093] The laser light reflected by measurement target point 226 is reflected again by half mirror 720 and received by sensor 719. The laser light that has passed through measurement target point 226 is reflected by measurement target point 227 of bubble 200 and passes through measurement target point 226 from the inside to the outside in the radial direction. The laser light that has passed through measurement target point 226 is reflected again by half mirror 720 and received by sensor 719.

[0094] Of the laser light emitted from the sensor 719, a portion of the laser light that passes through the half mirror 720 is reflected by the half mirror 721 and a portion of the laser light passes through the half mirror 721. Of the laser light that passes through the half mirror 720, a portion of the laser light that is reflected by the half mirror 721 is reflected by the measurement target point 228 and a portion of the laser light passes through the measurement target point 228.

[0095] The laser light reflected by measurement target point 228 is reflected again by half mirror 721, passes through half mirror 720 from top to bottom in the vertical direction, and is received by sensor 719. The laser light that passed through measurement target point 228 is reflected by measurement target point 229 of bubble 200, and passes through measurement target point 228 from the inside to the outside in the radial direction. The laser light that passed through measurement target point 228 is reflected again by half mirror 721, passes through half mirror 720 from top to bottom in the vertical direction, and is received by sensor 719.

[0096] Furthermore, of the laser light emitted from sensor 719, the laser light that passes through half mirrors 720 and 721 is at least partially reflected by half mirror 722, partially reflected by measurement target point 230, and partially transmitted through measurement target point 230. The laser light reflected by measurement target point 230 is reflected again by half mirror 722, passes through half mirrors 721 and 720 from the top to the bottom in the vertical direction, and is received by sensor 719.

[0097] The laser light that has passed through measurement point 230 is reflected by measurement point 231 of bubble 200 and passes through measurement point 230 from the inside to the outside in the radial direction. The laser light that has passed through measurement point 230 is reflected again by half mirror 722, passes through half mirrors 721 and 720 from the top to the bottom in the vertical direction, and is received by sensor 719. This makes it possible to grasp the shape of bubble 200 based on the measurement distances to measurement points 226 to 231 at a certain timing.

[0098] In summary, the measuring devices 71 and 72 according to the seventh embodiment of the present invention only need to have the following configuration, and can take on a variety of different embodiments. That is, measuring device 71 (or measuring device 72) is a measuring device characterized by having a mirror arranged on the outer surface side of a thin-film cylindrical bubble 200, which is an example of a cylindrical molten resin whose shape changes over time, and sensors 711 and 712 (or sensor 719) that emit and receive laser light from the outer surface side of bubble 200 via the mirror to measure information indicating the state of bubble 200.

[0099] Here, the mirror arranged on at least one of the inner and outer sides of the bubble 200 may be a plurality of half mirrors 713 to 718 (or half mirrors 720 to 722) arranged at intervals in the axial direction of the bubble 200. As a result, the combination of half mirrors 713 to 718 and sensors 711 and 712, which are arranged on the outer surface side of bubble 200, makes it possible to measure the measurement target distance, which indicates the state of each of measurement target points 220 to 225 at a certain time. Furthermore, the combination of half mirrors 720 to 722 and sensor 719, which are arranged on the outer surface side of bubble 200, makes it possible to measure the measurement target distance, which indicates the state of each of measurement target points 226 to 231 at a certain time. As a result, information indicating the shape of bubble 200 can be efficiently obtained as information indicating the state of bubble 200.

[0100] <Eighth embodiment> FIG. 12 is a diagram showing an example of the configuration of a measuring device 81 according to the eighth embodiment. A measuring device 81 shown in FIG. 12 is a device that is applied to an inflation molding device 80, and is a device that can measure the state of a bubble 200 formed by the inflation molding device 80.

[0101] Measuring device 81 includes sensor 811 and one cone mirror 812, and is capable of measuring information indicating the state at a certain timing of bubble 200 being fed forward. Specifically, measuring device 81 is capable of measuring a measurement target distance as information indicating the state at a certain timing of bubble 200.

[0102] Sensor 811 is a laser distance sensor installed near the radially inner axis of bubble 200. Sensor 811 emits laser light toward cone mirror 812, which is located on the top side of sensor 811 in the vertical direction, and receives the laser light from cone mirror 812 to measure the distance to the target object.

[0103] Cone mirror 812 moves in the vertical direction of bubble 200, reflecting laser light from the bottom side of the vertical direction toward the outside in the radial direction of bubble 200. In the example of FIG. 12, laser light emitted from sensor 811 and reflected by cone mirror 812 is reflected by measurement target area 232 or 233, reflected again by cone mirror 812, and received by sensor 811. This makes it possible to grasp the shape of bubble 200 in three dimensions based on the measurement target distance at a certain time in measurement target areas 232 and 233. Cone mirror 812 may also be configured not to move in the vertical direction. In this case, it becomes possible to grasp the circumferential shape of bubble 200 based on the measurement target distance at a certain position in measurement target areas 232 and 233 at predetermined time intervals.

[0104] 12 is fixed, sensor 811 may alternatively emit laser light toward cone mirror 812 while rotating in the circumferential direction of bubble 200 and receive the laser light reflected by cone mirror 812. This increases the diameter of the focal point of the laser light on cone mirror 812, allowing the laser light to be efficiently reflected by cone mirror 812. Another method for increasing the diameter of the focal point of the laser light on cone mirror 812 may be to use sensor 811 as a collection of multiple sensors arranged in a ring shape in the circumferential direction of bubble 200, thereby increasing the diameter of the focal point of the laser light on cone mirror 812.

[0105] There is no particular limitation on the method for installing the sensor 811 and the cone mirror 812. For example, a structure 300 extending in the vertical direction may be installed near the radially inner axis of the bubble 200, and the sensor 811 and the cone mirror 812 may be installed on the structure 300.

[0106] In summary, the measuring device 81 according to the eighth embodiment of the present invention only needs to have the following configuration, and can take on a variety of different embodiments. In other words, measuring device 81 is a measuring device characterized by having a mirror arranged on the inner surface of a thin-film cylindrical bubble 200, which is an example of a cylindrical molten resin whose shape changes over time, and a sensor 811 that emits and receives laser light from the inner surface of bubble 200 via the mirror to measure information indicating the state of bubble 200.

[0107] Here, the mirror arranged on the inner surface side of the bubble 200 may be a cone mirror 812 that is movable in the axial direction of the bubble 200 . This makes it possible to measure the measurement target distance, which indicates the state at a certain point in time of measurement target regions 232 and 233, by combining cone mirror 812, which is arranged on the inner surface side of bubble 200 and can move in the axial direction of bubble 200, with sensor 819. As a result, information indicating the shape, which is information indicating the state of bubble 200, can be efficiently obtained.

[0108] <Measuring the bubble temperature> According to the measurement devices of the first to eighth embodiments described above, the combination of one or more laser distance sensors and one or more mirrors can efficiently measure the shape and film thickness as information indicating the state of the bubble. Furthermore, although not shown, the one or more laser distance sensors constituting the measurement devices of the first to eighth embodiments described above may be replaced with one or more temperature sensors. In this case, the combination of one or more temperature sensors and one or more mirrors can efficiently measure the temperature as information indicating the state of the bubble.

[0109] <When the present invention is not applied> Fig. 13(A) is a diagram showing an example of a bubble abnormality, and Fig. 13(B) and (C) are diagrams showing an example of measuring the state of a bubble using only a sensor without applying the present invention. The measuring devices according to the first to eighth embodiments described above can efficiently measure information indicating the state of bubbles by combining a sensor and a mirror, which makes it possible to quickly grasp bubble abnormalities such as "diameter fluctuation" where the bubble diameter fluctuates, "axis fluctuation" where the bubble axis fluctuates, and "shape distortion" where the bubble shape is distorted, as shown by the dashed lines in Fig. 13(A).

[0110] In contrast, when a method of measuring the state of bubbles using only a sensor without using a mirror is used, the following problems arise: Methods of measuring the state of bubbles using only a sensor without using a mirror include a method of installing a sensor at each predetermined measurement point and measuring simultaneously, as shown in Figure 13(B), a method of installing a single sensor that can move in the circumferential and axial directions of the bubble and measuring, as shown in Figure 13(C), and a method that combines these methods.

[0111] However, the method shown in Figure 13(B) is inefficient because it requires an increase in the number of measurement points and therefore an increase in the number of sensors in order to measure information indicating the state of the bubble. Furthermore, the method shown in Figure 13(C) is inefficient because it requires a drive mechanism for moving the sensor in the circumferential and axial directions of the bubble, as well as a structure for its installation. Furthermore, because the configuration requires a single sensor to measure while moving, it is not possible to simultaneously measure multiple measurement points on the bubble.

[0112] <Other> Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. Furthermore, the effects of the present invention are not limited to those described in the above-described embodiments. For example, the configurations of the measurement devices 11 to 81 shown in FIGS. 1 to 7 and 9 to 12 and the various mirrors shown in FIG. 8 are merely examples for achieving the objects of the present invention and are not particularly limited. Furthermore, in the above-described embodiments, inflation molding is used as an example of a molding method to which the present invention can be applied, but molding methods to which the present invention can be applied are not limited to inflation molding. The present invention can be applied to any molding method that includes a process of solidifying a cylindrical molten resin whose shape changes over time. [Explanation of symbols]

[0113] 10, 20, 30, 40, 50, 60, 70, 80... Blown film molding device, 11, 12, 13, 21, 31, 41, 51, 61, 71, 72, 81... Measuring device, 111, 113, 114, 211, 311, 312, 411, 511, 512, 513, 611, 612, 711, 712, 719, 811... Sensor, 112, 116, 212, 313, 412, 514, 515, 516... Galvanometer mirror, 613, 614, 615, 616, 617, 618, 713 , 714, 715, 716, 717, 718, 720, 721, 722...Half mirror, 812...Cone mirror, 200...Bubbles, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 213, 232, 233, 241, 242...Measurement area, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231...Measurement point, 300...Structure

Claims

1. a mirror disposed on at least one of the inner surface and the outer surface of a cylindrical molten resin whose shape varies with time; a sensor that transmits and receives light for measuring information indicating the state of the molten resin from the inner surface side or the outer surface side of the molten resin via the mirror; A measuring device comprising:

2. the mirror is disposed on an inner surface side of the molten resin, The sensor transmits and receives the light via the mirror on the inner surface side of the molten resin. The measurement device according to claim 1 .

3. The mirror is a galvanometer mirror that can rotate about a rotation axis in a predetermined direction relative to the molten resin. The measurement device according to claim 2 .

4. the mirror is a plurality of half mirrors arranged at intervals in the axial direction of the molten resin, The measurement device according to claim 2 .

5. The mirror is a cone mirror that is movable in the axial direction of the molten resin. The measurement device according to claim 2 .

6. the mirror is disposed on an inner surface side of the molten resin, The sensor transmits and receives the light from the outer surface side of the molten resin via the mirror. The measurement device according to claim 1 .

7. the mirror is further disposed on the outer surface side of the molten resin, the sensor transmits and receives the light from the outer surface side of the molten resin via the mirrors disposed on both the outer surface side and the inner surface side of the molten resin. The measurement device according to claim 6.

8. the mirror is disposed on an outer surface side of the molten resin, The sensor transmits and receives the light from the outer surface side of the molten resin via the mirror. The measurement device according to claim 1 .

9. the mirrors are disposed on the inner and outer surfaces of the molten resin, The sensor transmits and receives the light from the inner surface side and the outer surface side of the molten resin via the mirror. The measurement device according to claim 1 .

10. The information indicating the state of the molten resin is measured by measuring at least one of the shape, film thickness, and temperature of the molten resin. The measurement device according to claim 1 .

11. a step of placing a mirror on at least one of an inner surface side and an outer surface side of a cylindrical molten resin whose shape varies with time; a step of transmitting and receiving light from a sensor that measures information indicating the state of the molten resin from an inner surface side or an outer surface side of the molten resin via the mirror; A measuring method comprising:

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