JP2024159179A - Deformation measurement method and sensor - Google Patents

Abstract

[Problem] To provide a measurement method and sensor that uses a deformation measurement sensor using a sheet body with a kirigami structure to accurately measure the state of deformation due to large deformation of a measured part. [Solution] The sensor is made of a flexible, approximately rectangular resin film, with notches extending in the width direction between both longitudinal ends periodically provided in the longitudinal direction, and a strain-responsive resistive film is provided in each of the spaces between adjacent notches on the same surface of the resin film in the longitudinal direction. These both ends are fixed across the measured part, and when the both ends are moved apart in the longitudinal direction as the measured part deforms, the notches open, causing rotational deformation of the spaces, and the deformation state of the measured part is measured from the resistance change of the strain-responsive resistive film provided only at the positions where the spaces are either compressed or tensilely deformed. [Selected Figure] Figure 1

Description

The present invention relates to a deformation measurement method and a sensor using a sheet body with a kirigami structure.

By making regular cuts in paper and stretching it, the cuts open and deformation, including rotation, occurs in some parts, resulting in a three-dimensional structure. This type of structure, known as a "kirigami structure," is used as a cushioning material to protect bottles and other items. In addition, proposals have been made to use the rising structure of the three-dimensional part, including rotation, in devices, as well as mechanical sensors that use the large deformation caused by the opening of the cuts as a spring.

For example, Patent Document 1 discloses a mechanical sensor that uses a paper cutting structure. Alternating cuts extending in the width direction are made along the length of the sheet, and a load is applied to the sheet, and the stretching load when the cuts open is measured with a strain gauge. By determining the deformation of the sheet relative to the load when a specified cut is made, the load can be found from the measured strain at a specific point on the sheet.

International Publication No. 2017/179716

A mechanical sensor made of a sheet body with a paper-cutting structure that uses the large deformation caused by the opening of the slits as a spring will deform in response to the large deformation of the part to be measured. By providing a strain sensor, such as a strain-responsive resistive film that can change resistance value in response to either positive or negative strain, on the surface of the sheet body, it is possible to measure the deformation state of the part to be measured from the change in resistance value. However, the opening of the slits due to the large deformation is not stable, and as a result, the signal from the strain sensor on the surface of the sheet body is also not stable, making it difficult to accurately measure the deformation state of the part to be measured due to the large deformation.

The present invention was made in consideration of the above situation, and its purpose is to provide a measurement method and a sensor that can accurately measure the state of deformation caused by large deformation of the measured part using a deformation measurement sensor that uses a sheet body with a kirigami structure.

The measurement method according to the present invention is a deformation measurement method using a deformation measurement sensor that deforms in response to deformation of a measured part and measures the deformation state of the measured part, the deformation measurement sensor is made of a flexible, approximately rectangular resin film, and has notches extending in the width direction between both ends in the longitudinal direction, periodically provided in the longitudinal direction, and a strain-responsive resistive film is provided in each of the spaces between the notches that are adjacent to each other on the same surface of the resin film in the longitudinal direction, and the both ends of the deformation measurement sensor are fixed across the measured part, and when the both ends are moved apart along the longitudinal direction in response to deformation of the measured part, the notches open and cause rotational deformation of the spaces, and the deformation state of the measured part is measured from the resistance change of the strain-responsive resistive film provided only at the positions of the spaces that are either compressively deformed or tensilely deformed.

This feature makes it possible to accurately measure the deformation state of the part being measured due to large deformation.

In the above-mentioned invention, the cuts may be arranged so that a first row of two cuts cut from both side ends toward the center line in the width direction and a second row of one cut from the center line toward both side ends of the resin film are alternately provided at equal intervals in the longitudinal direction. This feature makes it possible to accurately measure the deformation state due to large deformation of the measured portion. This feature makes it possible to relatively uniformly deform the entire sheet body and accurately measure the deformation state due to large deformation of the measured portion.

The deformation measuring sensor according to the present invention is a deformation measuring sensor that deforms in response to deformation of a measured part and measures the deformation state of the measured part, and the deformation measuring sensor is made of a flexible, approximately rectangular resin film, and has notches extending in the width direction between both ends in the longitudinal direction, periodically arranged in the longitudinal direction, and a strain-responsive resistive film is provided in each of the spaces between the notches that are adjacent to each other on the same surface of the resin film in the longitudinal direction, and the both ends of the deformation measuring sensor are fixed across the measured part, and when the both ends are moved apart along the longitudinal direction in response to deformation of the measured part, the notches open and cause rotational deformation of the spaces, and the strain-responsive resistive film is provided only at positions where the spaces are either compressed or tensilely deformed.

This feature makes it possible to accurately measure the deformation state of the part being measured due to large deformation.

In the above-mentioned features, the cuts may be arranged alternately at equal intervals in the longitudinal direction, with a first row consisting of two cuts cut from both side edges toward the center line in the width direction, and a second row consisting of one cut from the center line toward both side edges of the resin film.

In the above-mentioned features, the strain-responsive resistive film may be provided on the center line in the intermediate portion from the first row to the second row along the longitudinal direction, or on the center line in the intermediate portion from the second row to the first row along the longitudinal direction. Here, the strain-responsive resistive film provided in each intermediate portion may be connected in parallel.

In the above-mentioned features, the strain-responsive resistive film may be provided on both sides of the center line in the width direction of the gap between the first row and the second row along the longitudinal direction, or on both sides of the center line in the width direction of the gap between the second row and the first row along the longitudinal direction. Alternatively, the strain-responsive resistive film may be provided on the center line in the gap between the first row and the second row along the longitudinal direction, and on both sides of the center line in the gap between the second row and the first row along the longitudinal direction. Here, the strain-responsive resistive film provided on both sides of the center line in the width direction in the gap may be connected in series, and the strain-responsive resistive film provided in each gap may be connected in parallel.

1 is a photograph showing the appearance of a deformation measuring sensor according to an embodiment of the present invention. 13 is a photograph showing the appearance of a deformation measuring sensor in which both ends are separated and deformation is applied. FIG. 2 is a plan view of the deformation measuring sensor 10a. FIG. 2 is a perspective view showing a deformed state of the deformation measuring sensor 10a. 4 is a plan view showing an example of wiring of the deformation measuring sensor 10a. FIG. 10 is a perspective view showing a deformed state of the deformation measuring sensor 10b. FIG. FIG. 4 is a plan view of the deformation measuring sensor 10c. 10 is a perspective view showing a deformed state of the deformation measuring sensor 10c. FIG. 10 is a plan view showing an example of wiring of the deformation measuring sensor 10c. FIG. 10 is a perspective view showing a deformed state of the deformation measuring sensor 10d. FIG. 1A is a plan view including wiring of a deformation measuring sensor 10e, and FIG. 1B is a plan view including wiring of a deformation measuring sensor 10f. FIG. 2 is a plan view of the deformation measuring sensor 10g. FIG. 2 is a plan view of a deformation measuring sensor (Examples 1 to 3) used in a manufacturing test. FIG. 2 is a plan view of a deformation measuring sensor (Comparative Examples 1 and 2) used in a manufacturing test. 11 is a graph showing the relationship between the elongation rate and the rate of change in resistance when the deformation measuring sensor is elongated. 10A is a graph showing the relationship between the extension rate and the rate of change in resistance when the deformation measuring sensor of the example (a) and the comparative example (b) is extended and then contracted.

Below, a deformation measurement sensor according to one embodiment of the present invention and a deformation measurement method using the same sensor will be described with reference to Figures 1 to 12.

As shown in FIG. 1, the deformation measuring sensor 10 is made of a flexible, approximately rectangular resin film 1, and has notches 3 extending in the width direction between both longitudinal ends 2a and 2b, which are periodically provided in the longitudinal direction. The notches 3 give the deformation measuring sensor 10 a paper-cut structure that allows for relatively uniform large deformation. The resin film 1 does not need to be stretchable by itself, and for example, polyethylene, polypropylene, polyethylene terephthalate (PET), polycarbonate, and polyimide can be suitably used. Note that any flexible material that does not need to be stretchable may be used, such as an insulating-coated metal foil or ultra-thin glass. The notches 3 can be provided by appropriate machining according to the material of the resin film 1, such as laser cutting or punching.

The deformation measuring sensor 10 also includes a strain-responsive resistive film 5 that changes its electrical resistance by straining in response to the deformation of the resin film 1, and is provided with wiring 6 and electrodes 7a and 7b for detecting the electrical resistance of the strain-responsive resistive film 5. The strain-responsive resistive film 5 is preferably made of a material that exhibits a large change in resistance to strain, such as a conductive paste containing conductive particles with a relatively large particle size on the order of microns. The wiring 6 is preferably made of a material that exhibits a small change in resistance to strain, such as a thin metal film formed by sputtering, vapor deposition, plating, or the like, or a printed film of a conductive paste that contains dense metal nanoparticles. The arrangement of the strain-responsive resistive film 5, wiring 6, and electrodes 7a and 7b will be described later.

As shown in FIG. 2, the deformation measuring sensor 10 rotates and deforms the space 4 between the adjacent notches 3 in the longitudinal direction when the notches 3 are opened by pulling the notches 3 between the ends 2a and 2b when the deformation measuring sensor 10 is moved away from the ends 2a and 2b. In other words, the notches 3 are arranged so that the space 4 is rotated and deformed when the notches 3 are pulled away from the ends 2a and 2b and opened. Here, the rotational deformation is a deformation that generates a rotation in a plane that is perpendicular to the plane of the resin film 1 before the ends 2a and 2b are moved away from the ends and includes the longitudinal direction, and further generates a bending in which the front and back of each part of the resin film 1 are respectively tensile and compressed, or compressed and tensile.

The deformation measuring sensor 10 is provided with a strain-responsive resistive film 5 on the same surface of the resin film 1 and in each of the gaps 4. In particular, the strain-responsive resistive film 5 is provided only in the positions of the gaps 4 that are subject to either compressive deformation or tensile deformation due to rotational deformation. In the example shown in the figure, the strain-responsive resistive film 5 is formed only in the portions that are subject to tensile deformation.

Such a deformation measuring sensor 10 is fixed at both ends 2a and 2b across the measured part of the object whose deformation state is to be measured. Then, the deformation of the measured part causes a rotational deformation of the intermediate part 4 corresponding to the distance between the both ends 2a and 2b. Then, of the bending of the resin film 1 caused by the rotational deformation, only the compressive deformation or the tensile deformation of the surface on the front side (the side on which the strain-responsive resistive film 5 is arranged) can be detected from the electrical resistance of the strain-responsive resistive film 5. According to such a deformation measuring method, by detecting only the compressive deformation or only the tensile deformation, the deformation state of the measured part can be measured more accurately than a method using a sensor with a strain-responsive resistive film arranged to mix both compression and tension.

The deformation measuring sensor 10 can measure the deformation state of the measured part by separating both ends 2a and 2b. Therefore, the deformation of the measured part may not only be a simple stretching in one axial direction, but also a deformation like the expansion of a rubber balloon. In other words, the deformation measuring sensor 10 does not have to completely follow the deformation of the measured part, but only needs to be able to deform as a whole in response to the deformation state of the measured part while following the displacement of the part to which both ends 2a and 2b in the longitudinal direction are fixed.

Furthermore, we will explain more specific examples of the arrangement of the notches 3 and the strain-responsive resistive film 5.

For example, as shown in FIG. 3, in the deformation measuring sensor 10a, the cut 3 is composed of a first row of two cut portions 3a and a second row of one cut portion 3b. The cut portions 3a are cut from both ends in the width direction toward the center line C in the width direction. The cut portions 3b are cut from the center line C toward both ends of the resin film. The cuts 3 can be arranged such that the first and second rows are alternately arranged at equal intervals in the longitudinal direction. In this case, the strain-responsive resistive film 5 is arranged on the front side of the resin film 1 on the center line C, which is the portion 4a between the first row and the second row from the top to the bottom of the paper along the longitudinal direction. On the other hand, the strain-responsive resistive film 5 is not arranged on the center line C of the portion 4b between the second row and the first row. In the following, the order of the rows due to the cuts, such as the section 4a between the first row and the second row, will be expressed in the longitudinal direction from the top to the bottom of the page (from end 2a to end 2b).

Referring also to FIG. 4, when the notch 3 and the strain-responsive resistive film 5 are arranged as described above, if the two ends 2a and 2b are separated, for example, the portion 4a between the first row and the second row bends so as to rise upward at the center in the width direction, and the strain-responsive resistive film 5 arranged on the upper surface is located outside the bending of the resin film 1. In other words, this strain-responsive resistive film 5 undergoes tensile deformation. On the other hand, the portion 4b between the second row and the first row bends so as to sink downward at the center in the width direction. By arranging the notch 3 and the strain-responsive resistive film 5 in this manner, it becomes possible to detect only the tensile deformation. Note that in the figure, the rotation of the rotational deformation of the portions 4a and 4b is omitted. In reality, the lower left end of the portion 4a on the paper is moved upward, and the strain-responsive resistive film 5 is rotated so as to be hidden on the back side of the paper of the resin film 1. This makes it possible to relatively uniformly deform the entire sheet body made of the resin film 1 to a large extent.

When both ends 2a and 2b are separated, the rotational movement of the intermediate portions 4a and 4b may be in the opposite direction to that described above, but in that case, the strain-responsive resistive film 5 is arranged to detect only compressive deformation. The direction of this rotational movement may vary depending on the orientation of the main surfaces of both ends 2a and 2b, the quirks of the resin film, wiring, etc., but when rotational deformation occurs, the rotational movement occurs in the same direction in all of the intermediate portions 4a and 4b. As for bending, if the center of the intermediate portion 4a from the first row to the second row is convex upward, the center of the intermediate portion 4b from the second row to the first row is convex downward. In other words, the intermediate portions 4a and 4b are bent in opposite directions, which opens the notch 3.

As shown in FIG. 5, with respect to the arrangement of the notches 3 and strain-responsive resistive films 5 described above, all of the strain-responsive resistive films 5 can be connected in parallel by wiring 6. For example, the deformation measuring sensor 10a-1 (FIG. 5(a)) is an example in which both electrodes 7a and 7b are arranged at the end 2a. Moreover, the deformation measuring sensor 10a-2 (FIG. 5(b)) is an example in which, of the pair of electrodes 7a and 7b, electrode 7a is arranged at the end 2a and electrode 7b is arranged at the end 2b.

As shown in FIG. 6, in the deformation measuring sensor 10b, the strain-responsive resistive film 5 is disposed on the center line C of the portion 4b between the second row and the first row. On the other hand, the strain-responsive resistive film 5 is not disposed on the center line C of the portion 4a between the first row and the second row. In this case, if rotational deformation occurs as in the above-mentioned deformation measuring sensor 10a (see FIG. 4), the strain-responsive resistive film 5 can detect only compressive deformation.

Next, as shown in FIG. 7, the arrangement of the strain-responsive resistive film 5 can be further changed. As described above, the strain-responsive resistive film 5 only needs to be provided at positions where the rotationally deformed gap 4 undergoes either compressive deformation or tensile deformation. Therefore, in the deformation measurement sensor 10c, the strain-responsive resistive film 5 is disposed at the gap 4a between the first and second rows, on both sides of the center line C in the width direction.

Referring also to FIG. 8, when the notches 3 and the strain-responsive resistive film 5 are arranged as described above, and the two ends 2a and 2b are separated, for example, the portion 4a between the first and second rows bends downward at the left and right portions in the width direction, and the strain-responsive resistive film 5 arranged on its upper surface is located inside the bend of the resin film 1. In other words, this strain-responsive resistive film 5 undergoes compressive deformation. On the other hand, the portion 4b between the second and first rows bends upward at the left and right portions in the width direction. By arranging the notches 3 and the strain-responsive resistive film 5 in this way, it becomes possible to detect only compressive deformation.

As shown in FIG. 9, all of the strain-responsive resistive films 5 can be connected by wiring 6 to the arrangement of the notches 3 and strain-responsive resistive films 5 described above. The strain-responsive resistive films 5 on the left and right sides of the center line C are connected in series as pairs, and these pairs are connected in parallel. For example, the deformation measuring sensor 10c-1 (FIG. 9(a)) is an example in which both electrodes 7a and 7b are arranged at the end 2a. The deformation measuring sensor 10c-2 (FIG. 9(b)) is an example in which, of the pair of electrodes 7a and 7b, electrode 7a is arranged at the end 2a and electrode 7b is arranged at the end 2b.

As shown in FIG. 10, in the deformation measuring sensor 10d, a strain-responsive resistive film 5 is arranged on both sides of the center line C in the portion 4b between the second row and the first row. On the other hand, a strain-responsive resistive film 5 is not arranged on both the left and right sides of the center line C in the portion 4a between the first row and the second row. In this case, if a rotational deformation occurs as in the above-mentioned deformation measuring sensor 10c (see FIG. 8), the strain-responsive resistive film 5 can detect only tensile deformation.

Furthermore, as shown in FIG. 11, a different arrangement can be used that utilizes the arrangement of the strain-responsive resistive film 5 described above.

For example, as shown in FIG. 1A, in the deformation measuring sensor 10e, the strain-responsive resistive film 5 is arranged on the center line C in the longitudinal portion 4a between the first and second rows, and on both sides of the center line C in the longitudinal portion 4b between the second and first rows. In other words, the arrangement of the strain-responsive resistive film 5 of the deformation measuring sensor 10a (see FIG. 4) and 10d (see FIG. 10) described above is combined. With this, if the deformation measuring sensor 10a is subjected to rotational deformation in the same way as the deformation measuring sensor 10a, the strain-responsive resistive film 5 can detect only tensile deformation. Also, if the unevenness is reversed due to rotational deformation, only compressive deformation can be detected.

On the other hand, as shown in FIG. 1B, the strain-responsive resistive film 5 is disposed only at one location on the center line C, in the portion 4a between the first and second rows. This also allows the strain-responsive resistive film 5 to detect only compressive deformation or only tensile deformation.

As shown in FIG. 12, the notch 3 can also be in another form. For example, the deformation measuring sensor 10g has a notch 3 in which two of the above-mentioned deformation measuring sensors 10a are connected side by side in the width direction.

In detail, first, assume a center line C1 in the width direction of the approximately rectangular resin film 1, and a left center line CL and a right center line CR located at a distance of approximately four equal parts of the width from the left and right sides. The first row of cuts 3 on the upper side of the paper has cut parts 3c cut from both side ends in the width direction toward the center line C1, and cut parts 3d cut from the center line C1 toward both side ends. The cut parts 3c and 3d are provided at a fixed distance from the left center line CL and the right center line CR. The second row of cuts 3 has cut parts 3e extending from the left center line CL and the right center line CR toward both side ends in the width direction. The cut parts 3e are provided at a fixed distance from the center line C1 and at a fixed distance from both left and right side ends. The first and second rows of cuts 3 are arranged alternately at equal intervals in the longitudinal direction.

The strain-responsive resistive film 5 is disposed on the front side (the front side of the page) of the resin film 1 in the area 4a between the first and second rows, on the left center line CL and the right center line CR, and in the area 4b between the second and first rows, on the center line C1.

Even with this type of deformation measuring sensor 10g, when both ends 2a and 2b are separated in the longitudinal direction (up and down on the paper), the notches 3 open, causing rotational deformation of the intermediate portions 4a and 4b between the longitudinally adjacent notches 3. The strain-responsive resistive film 5 is disposed only in the portions that become upwardly convex (or concave) when the intermediate portions 4a and 4b are rotationally deformed, making it possible to detect only tensile deformation (or only compressive deformation).

[Production testing]
Next, the deformation measuring sensor was actually manufactured and the test was performed will be described with reference to Fig. 13 to Fig. 16. The resin film used was polyethylene terephthalate (PET, manufactured by Toyobo Co., Ltd., product name: Cosmoshine) with a thickness of 0.1 mm. The strain-responsive resistive film was made of a conductive film forming ink mainly made of conductive carbon (manufactured by Namics Corporation, product code: XKT10400), and the wiring was made of a conductive film forming ink mainly made of silver particles (manufactured by Toyo Ink Co., Ltd., product code: RAFS059S), which was screen-printed, dried, and cured.

As shown in FIG. 13, the deformation measuring sensor 10e-1 of Example 1 differs from the above-mentioned deformation measuring sensor 10e in that the electrode 7b is placed at the end 2b on the lower side of the paper surface, but is otherwise similar. That is, the deformation measuring sensor 10e-1 has the strain-responsive resistive film 5 placed on the center line C in the portion 4a between the first row and the second row along the longitudinal direction, and on both sides of the center line C in the portion 4b between the second row and the first row along the longitudinal direction.

As described above (see FIG. 5), the deformation measuring sensor 10a-2 of Example 2 has the strain-responsive resistive film 5 disposed in the portion 4a between the first and second rows, on the front side of the resin film on the center line C (the front side of the page).

Furthermore, the deformation measuring sensor 10d-1 of Example 3 is configured by disposing a strain-responsive resistive film and then wiring it in the same manner as the deformation measuring sensor 10d described above. That is, the deformation measuring sensor 10d-1 is configured in the portion 4b between the second row and the first row, with strain-responsive resistive films 5 disposed on both sides of the center line C in the width direction.

As shown in Figure 14, deformation measurement sensors were also fabricated as Comparative Example 1 and Comparative Example 2.

The deformation measuring sensor of Comparative Example 1 has a strain-responsive resistive film 5 disposed over the entire surface, except for both ends in the width direction of the intermediate portions 4a and 4b. The deformation measuring sensor of Comparative Example 2 has a strain-responsive resistive film 5 disposed on the center line C in both the intermediate portion 4a between the first row and the second row, and the intermediate portion 4b between the second row and the first row.

As shown in Figure 15, the relationship between the elongation rate and the resistance change rate as a deformation measuring sensor when both ends 2a and 2b are separated from each other was investigated for Examples 1 to 3 and Comparative Example 1 and Comparative Example 2. As a result, Examples 1 to 3 showed a large resistance change rate compared to the Comparative Examples. Among the Examples, Example 1 had the largest resistance change rate, followed by Examples 2 and 3. The reason why the resistance change rates are small in Comparative Examples 1 and 2 is thought to be due to a mixture of an increase in resistance due to elongation strain accompanying tensile deformation and a decrease in resistance due to compression strain accompanying compressive deformation.

As shown in Figure 16, the relationship between the elongation rate and the rate of resistance change as a deformation measuring sensor was investigated for Examples 1 to 3 and Comparative Example 1 and Comparative Example 2 when both ends 2a and 2b were moved away from each other and then returned to their original positions. As a result, Examples 1 to 3 showed high linearity and small hysteresis (Figure 16(a)), while Comparative Example 1 and Comparative Example 2 both showed relatively low linearity, and Comparative Example 1 also showed relatively large hysteresis (Figure 16(b)). In Comparative Example 1, the strain-responsive resistive film was placed over the entire surface, which is thought to have caused very large strains locally and was affected by plastic deformation and residual stress.

As described above, the deformation measurement sensors of Examples 1 to 3 can obtain linear resistance changes in response to stretching with high accuracy and high sensitivity.

Although the above describes representative embodiments of the present invention, the present invention is not necessarily limited thereto, and a person skilled in the art will be able to find various alternative embodiments and modifications without departing from the spirit of the present invention or the scope of the appended claims.

REFERENCE SIGNS LIST 1 resin film 2a, 2b end portion 3 incisions 3a to 3e cut portion 4 (4a, 4b) space between them 5 strain-responsive resistive film 6 wiring 7a, 7b electrode 10 deformation measuring sensor

Claims (9)

A deformation measurement method using a deformation measurement sensor that deforms in response to deformation of a measurement target portion and provides a measurement of the deformation state of the measurement target portion,
the deformation measuring sensor is made of a flexible, substantially rectangular resin film, and has notches extending in a width direction between both ends in the longitudinal direction, the notches being periodically provided in the longitudinal direction, and a strain-responsive resistive film being provided in each of the portions between the notches adjacent to each other in the longitudinal direction on the same surface of the resin film;
A deformation measurement method characterized in that both ends of the deformation measuring sensor are fixed across the measured portion, and when the both ends are moved apart along the longitudinal direction as the measured portion deforms, the notch opens and causes rotational deformation of the intermediate portion, and the deformation state of the measured portion is measured from the resistance change of the strain-responsive resistive film that is provided only at positions of the intermediate portion that are either compressively deformed or tensilely deformed. The deformation measurement method according to claim 1, characterized in that the cuts are made in a first row consisting of two cuts cut from both side ends toward the center line in the width direction, and a second row consisting of one cut from the center line toward both side ends of the resin film, which are alternately made at equal intervals in the longitudinal direction. A deformation measuring sensor that deforms in response to deformation of a measurement target portion and provides a measurement of the deformation state of the measurement target portion,
the deformation measuring sensor is made of a flexible, substantially rectangular resin film, and has notches extending in a width direction between both ends in the longitudinal direction, the notches being periodically provided in the longitudinal direction, and a strain-responsive resistive film being provided in each of the portions between the notches adjacent to each other in the longitudinal direction on the same surface of the resin film;
The deformation measuring sensor is characterized in that both ends of the deformation measuring sensor are fixed across the measured portion, and when the both ends are moved apart along the longitudinal direction as the measured portion deforms, the notch opens and causes rotational deformation of the intervening portion, and the strain-responsive resistive film is provided only at positions where each of the intervening portions is either compressively deformed or tensilely deformed. The deformation measuring sensor according to claim 3, characterized in that the cuts are arranged alternately at equal intervals in the longitudinal direction, with a first row consisting of two cuts cut from both side ends toward the center line in the width direction, and a second row consisting of one cut from the center line toward both side ends of the resin film. The deformation measuring sensor according to claim 4, characterized in that the strain-responsive resistive film is provided on the center line in the intermediate portion between the first row and the second row along the longitudinal direction, or on the center line in the intermediate portion between the second row and the first row along the longitudinal direction. The deformation measuring sensor according to claim 5, characterized in that the strain-responsive resistive films provided in each of the intervening portions are connected in parallel. The deformation measuring sensor according to claim 4, characterized in that the strain-responsive resistive film is provided on both sides of the center line in the width direction in the intermediate portion from the first row to the second row along the longitudinal direction, or on both sides of the center line in the width direction in the intermediate portion from the second row to the first row along the longitudinal direction. The deformation measuring sensor according to claim 4, characterized in that the strain-responsive resistive film is provided on the center line in the intermediate portion between the first row and the second row along the longitudinal direction, and on both sides of the center line in the intermediate portion between the second row and the first row along the longitudinal direction. The deformation measuring sensor according to claim 7 or 8, characterized in that the strain-responsive resistive films provided on both sides of the center line in the width direction in the space between the electrodes are connected in series, and the strain-responsive resistive films provided in each of the space between the electrodes are connected in parallel.