Fiber sensor and fiber measuring method

Abstract

The present invention provides a fiber sensor and a fiber measuring method with which it is possible to measure the texture of a fiber by a simple operation.　A fiber sensor (AA) has one or a plurality of measurement units (10). The measurement unit (10) has: a plate-shaped frame (20); a fiber guide (30) having an introduction part and a terminal part formed in the frame (20); a contactor (40) that comes into contact with a fiber inserted into the fiber guide (30); a support body (50) that supports the contactor (40) so as to be displaceable with respect to the frame (20); and a displacement detector that detects displacement of the contactor (40) with respect to the frame (20). The texture of the fiber can be measured by a simple operation of inserting the fiber into the fiber guide (30) and scanning with the fiber sensor (AA).

Description

Fiber sensor and fiber measurement method

[0001] The present invention relates to a sensor for fibers and a method for measuring fibers. More specifically, the present invention relates to a sensor for quantitatively measuring the texture (texture and feel of the fiber surface) of fibers such as hair and yarn, and a method for measuring fibers using the same sensor.

[0002] Evaluating hair health is expected to have ripple effects not only in the beauty industry but also in the medical field, such as in the detection of aging, stress, and disease. Humans evaluate hair health through its texture. Healthy hair feels smooth and moist to the touch, while damaged hair feels dry and brittle. This texture reflects the condition of the hair cuticle. Healthy hair has multiple overlapping cuticles covering its surface, with a periodic surface structure that has intervals of 5 to 20 μm and steps of 0.3 to 0.6 μm. When hair is damaged, the cuticles peel back, causing variations in their spacing and steps. If the condition of the cuticle can be quantitatively measured, it will be possible to provide an index for evaluating hair health.

[0003] Furthermore, the feel of a fabric is influenced by the texture of the yarn that makes up that fabric. In other words, the texture of the yarn affects the quality of the fabric product. If the texture of the yarn can be measured quantitatively, it will be possible to select yarn suitable for the fabric product, and as a result, an improvement in the quality of the fabric product can be expected. Thus, there is a need for technology to quantitatively measure the texture (texture of the fiber surface, feel) of fibers such as hair and yarn.

[0004] Patent Document 1 discloses a tactile sensor having a minute contact element. By scanning the tactile sensor while pressing it against the object to be measured and detecting the displacement of the contact element, it is possible to measure the fine irregularities and frictional force of a minute area on the surface of the object to be measured. It is believed that the texture of fibers can be quantitatively measured using such a tactile sensor.

[0005] WO2015 / 133113 publication

[0006] To measure fibers using the tactile sensor disclosed in Patent Document 1, it is necessary to scan the tactile sensor along the fiber while maintaining the contact probe pressed against the fiber. However, because fibers are thin and flexible, the contact probe tends to slip, making the measurement operation difficult. Furthermore, the tactile sensor disclosed in Patent Document 1 has not only the contact probe but also the side of the frame in contact with the object being measured. Therefore, when scanning while pressing the tactile sensor against hair, the side of the frame damages the hair, and the contact probe measures the damaged area. This may prevent the measurement of the hair's original texture.

[0007] In view of the above circumstances, the present invention aims to provide a fiber sensor and a fiber measurement method that can measure the texture of fibers with simple operation.

[0008] The first embodiment of the fiber sensor comprises one or more measuring units, each measuring unit comprising: a flat plate-shaped frame having a main surface parallel to the x-y plane when three-dimensional spatial coordinates are defined by mutually orthogonal x, y, and z axes; a fiber guide having an introduction portion and an end portion following the introduction portion, which is a notch formed in the frame along the x axis and includes an opening located on the side surface of the frame; a contactor having a contact end that contacts a fiber inserted into the fiber guide; a support that supports the contactor so as to be displaceable relative to the frame in the x-axis direction and / or the z-axis direction; and a displacement detector that detects the displacement of the contactor relative to the frame in the x-axis direction and / or the z-axis direction, wherein the contact end protrudes from the bottom of the end portion to the extent that it does not reach the introduction portion when no external force is applied to the contactor. The second embodiment of the fiber sensor is characterized in that, in the first embodiment, the end portion of the fiber guide has a shape that tapers toward the bottom. The third embodiment of the fiber sensor is characterized in that, in the first or second embodiment, the width of the opening of the fiber guide in the y-axis direction is three times or more the diameter of the fiber. The fourth embodiment of the fiber sensor is characterized in that, in any of the first to third embodiments, the width of the contact end in the y-axis direction is 0.1 to 0.5 times the diameter of the fiber. The fifth embodiment of the fiber sensor is characterized in that, in any of the first to fourth embodiments, the bottom of the fiber guide is positioned at the shear center of the support when an external force is applied to the support in the z-axis direction. The sixth embodiment of the fiber sensor is characterized in that, in any of the first to fifth embodiments, the support consists of a plurality of beams arranged in the x-axis direction, each of the plurality of beams arranged along the y-axis and having a first end connected to the frame and a second end connected to the contactor, and the position of the bottom of the fiber guide in the x-axis direction is between the two outermost beams of the plurality of beams. The seventh embodiment of the fiber sensor is characterized in that, in any of the first to sixth embodiments, the plurality of measuring units are arranged in line in the y-axis direction, and the amount of protrusion of the contact end from the bottom is set to be different for each unit.The eighth aspect of the fiber measurement method is a fiber measurement method using a fiber sensor according to any of the first to seventh aspects, characterized in that the fiber sensor is scanned along the fiber while the contact end is in contact with the fiber, with the main surface of the fiber sensor inclined about the y-axis with respect to the axial direction of the fiber.

[0009] According to the first embodiment, the fiber guide makes it easy to maintain the state in which the fiber is pressed against the contactor, so the texture of the fiber can be measured with a simple operation of inserting the fiber into the fiber guide and scanning the fiber sensor. According to the second embodiment, because the end of the fiber guide is tapered, the fiber is easily guided to a position where it contacts the contactor simply by inserting the fiber into the fiber guide. According to the third embodiment, because the opening of the fiber guide is sufficiently wide compared to the diameter of the fiber, it is easy to insert the fiber into the fiber guide. According to the fourth embodiment, because the width of the contact end is smaller than the diameter of the fiber, a single fiber guided to the bottom of the fiber guide can be selectively measured. According to the fifth embodiment, because the frictional force generated between the fiber guided to the bottom of the fiber guide and the contactor acts on the shear center of the support, torsional deformation of the support can be suppressed. As a result, the displacement of the contactor in the x-axis direction can be measured with high accuracy. According to the sixth embodiment, because the frictional force generated between the fiber guided to the bottom of the fiber guide and the contactor acts on the shear center or near the center of the support, torsional deformation of the support can be suppressed. As a result, the displacement of the contactor in the x-axis direction can be measured with high accuracy. According to the seventh embodiment, multiple fibers can be measured simultaneously with multiple contacts having different protrusion amounts, thus obtaining measurement results for multiple load ranges at once. According to the eighth embodiment, by tilting the fiber sensor relative to the fiber, the corners of the contact ends come into contact with the fiber, thereby reducing the contact area. As a result, the texture of the fiber can be measured with high spatial resolution.

[0010] This is a plan view of the fiber sensor according to the first embodiment. This is a cross-sectional view taken along the line II-II in Figure 1. This is an enlarged plan view of the vicinity of the fiber guide. This is an explanatory diagram of the displacement detector. This is an explanatory diagram of the state in which a fiber is inserted into the fiber guide. This is an explanatory diagram of the scene in which the fiber sensor is tilted relative to the fiber and scanned. This is a graph illustrating various signals obtained from the displacement detector. This is a plan view of the fiber sensor according to the second embodiment. This is an explanatory diagram of the shear center of the support. Figure (A) is a cross-sectional view when a frictional force is applied to the contactor of the first embodiment. Figure (B) is a cross-sectional view when a frictional force is applied to the contactor of the second embodiment. Figure (A) is a graph showing the relationship between the x-axis displacement of the contactor and the output voltage of the x-direction displacement detector. Figure (B) is a graph showing the relationship between the z-axis load applied to the contactor and the output voltage of the z-direction displacement detector. Figure (A) is a graph showing the surface shape of hair obtained when the tilt angle θ of the fiber sensor is 0°. Figure (B) is a graph showing the surface shape of hair obtained when the tilt angle θ of the fiber sensor is 10°. Figure (A) is a graph showing the surface shape and frictional force obtained when the fiber sensor is scanned from the root to the tip of a hair. Figure (B) is a graph showing the surface shape and frictional force obtained when the fiber sensor is scanned from the tip to the root of a hair. This is a graph showing the surface shape obtained when six hairs are inserted into the fiber guide. Figure (A) is a graph showing the surface shape and frictional force obtained by a measuring unit with a contact end protrusion of 2 μm. Figure (B) is a graph showing the surface shape and frictional force obtained by a measuring unit with a contact end protrusion of 4 μm. Figure (C) is a graph showing the surface shape and frictional force obtained by a measuring unit with a contact end protrusion of 10 μm. This is a graph showing the surface shape obtained when yarn is measured.

[0011] Next, embodiments of the present invention will be described based on the drawings. [First Embodiment] The fiber sensor AA according to the first embodiment of the present invention is a sensor used for measuring the texture of fibers. The fiber to be measured can be any thin, thread-like substance. Although not particularly limited, examples of fibers include hair and thread. Fiber texture refers to the texture and feel of the fiber surface. In particular, the fiber sensor AA can measure fine irregularities and frictional forces in minute areas on the fiber surface.

[0012] As shown in Figures 1 and 2, the fiber sensor AA is formed by processing a semiconductor substrate using semiconductor micromachining technology. The mechanical structure of the fiber sensor AA is formed by etching the semiconductor substrate in a predetermined pattern to remove unwanted portions. Therefore, the fiber sensor AA is flat overall.

[0013] Below, the x, y, and z axes are defined based on the fiber sensor AA. The x, y, and z axes are orthogonal to each other, and these define the three-dimensional spatial coordinate system. The x and y axes are parallel to the main surfaces of the front and back of the fiber sensor AA. That is, the x-y plane is parallel to the main surfaces of the front and back of the fiber sensor AA. The z axis is perpendicular to the main surface of the fiber sensor AA and runs along the thickness direction of the fiber sensor AA.

[0014] The fiber sensor AA of this embodiment has a plurality of measuring units 10. The number of measuring units 10 is not particularly limited. In the illustrated example, the fiber sensor AA has three measuring units 10. The plurality of measuring units 10 are arranged in line along the y-axis. Therefore, the fiber sensor AA has a horizontally elongated shape (a shape that is long in the y-axis direction). The dimensions of each measuring unit 10 are not particularly limited, but are, for example, 1 to 10 mm square. Alternatively, the fiber sensor AA may have only one measuring unit 10.

[0015] The measuring section 10 has a roughly rectangular frame 20. The frame 20 is flat and has front and back main surfaces parallel to the x-y plane. A space 21 is formed in the central part of the frame 20, penetrating both the front and back. In addition, a notch is formed along the x-axis on one side of the frame 20. This notch is called a fiber guide 30. The fiber guide 30 communicates with the space 21 at its end.

[0016] A contact element 40 is positioned in the space 21. The contact element 40 is a rod-shaped member, and its central axis is positioned along the x-axis. A support body 50 is also positioned in the space 21. The support body 50 supports the contact element 40 so that it can be displaced in the x-axis and z-axis directions relative to the frame 20.

[0017] The configuration of the support 50 is not particularly limited, but the support 50 in this embodiment consists of a plurality of beams 51. Each beam 51 is arranged along the y-axis, with its first end connected to the frame 20 and its second end connected to the contactor 40. The plurality of beams 51 are arranged in line along the x-axis. In addition, beams 51 are arranged on both the left and right sides of the contactor 40.

[0018] The beam 51 is elastic and has properties similar to a leaf spring. Since the beam 51 is positioned along the y-axis, displacement of the contactor 40 in the x-axis direction is permitted, as is displacement in the z-axis direction.

[0019] The number and dimensions (length, width) of the beams 51 constituting the support 50 are not particularly limited. The number and dimensions of the beams 51 should be set so that the necessary elasticity for the support 50 is obtained. In addition, the support 50 may be composed of members other than beams, as long as the desired elasticity is obtained.

[0020] The support 50 may be configured such that the contact element 40 is displaced in either the x-axis direction or the z-axis direction. As described later, the fine irregularities of the fiber surface are measured from the x-axis direction displacement of the contact element 40, and the frictional force of a minute region on the fiber surface is measured from the z-axis direction displacement. If measuring the fine irregularities of the fiber surface is sufficient, the contact element 40 may be displaceable only in the x-axis direction. Also, if measuring the frictional force of a minute region on the fiber surface is sufficient, the contact element 40 may be displaceable only in the z-axis direction.

[0021] As shown in Figure 3, the fiber guide 30 has an opening 31. The opening 31 is located on one side 22 of the frame 20 along the y-axis. The fiber guide 30 is divided into two regions along the x-axis, with the portion including the opening 31 being called the introduction portion 32, and the portion following the introduction portion 32 being called the end portion 33. The end portion 33 has a tapered shape, such as a U-shape or a V-shape. The apex of the tapered shape of the end portion 33 is called the bottom portion 34. That is, the end portion 33 is tapered towards the bottom portion 34. The bottom portion 34 is in communication with the space portion 21 via a gap 23.

[0022] The contact element 40 has a contact end 41 that contacts the fiber F, which is the object to be measured. When no external force is applied to the contact element 40, the contact end 41 protrudes from the bottom 34 along the x-axis. However, the contact end 41 protrudes only slightly from the bottom 34. Even if the amount P of protrusion of the contact end 41 from the bottom 34 is increased, the contact end 41 is located at the end portion 33 and does not reach the introduction portion 32.

[0023] A fiber F is inserted into the fiber guide 30 through the opening 31. At this time, the fiber F is positioned so that its axis is roughly aligned with the z-axis. In other words, the fiber F is inserted into the fiber guide 30 in a position that penetrates both the front and back surfaces of the fiber sensor AA. The fiber F inserted into the fiber guide 30 is guided by the wall surface of the fiber guide 30 to the bottom 34 and comes into contact with the contact end 41. A force acts from the fiber F to the contact end 41, causing the contact element 40 to be displaced relative to the frame 20.

[0024] The shape of the end portion 33 should be such that the fiber F is easily guided to its apex (bottom portion 34). Examples of the shape of the end portion 33 include, but are not limited to, a parabola and a catenary curve. It is preferable that the curvature near the apex (bottom portion 34) of the end portion 33 is the same as or close to the curvature of the cross-section of the fiber F. This allows the fiber F to be stably positioned at the bottom portion 34.

[0025] Width W in the y-axis direction of the opening 31 of the fiber guide 30 １ It is preferable that the diameter of the fiber F is three times or more. For example, the diameter of a typical hair is 50 to 100 μm, with an average of 80 μm. When hair is assumed to be the object to be measured, the width W of the opening 31 is... １ The diameter is preferably 250 to 350 μm. If the opening 31 of the fiber guide 30 is made sufficiently wider than the diameter of the fiber F, the fiber F can be easily inserted into the fiber guide 30.

[0026] Width W in the y-axis direction of the bottom 34 (gap 23) of the fiber guide 30 ２ It is preferable that the width is 0.6 to 0.9 times the diameter of the fiber F. When hair is assumed to be the object to be measured, the width W of the bottom 34 (gap 23) ２ The width is preferably 50 to 70 μm. Width W of the bottom 34 (gap 23) ２By making the diameter smaller than that of the fiber F, the state in which a single fiber F is positioned at the bottom 34 can be stably maintained.

[0027] Width W in the y-axis direction of the contact end 41 ３ It is preferable that the width W of the contact end 41 is 0.1 to 0.5 times the diameter of the fiber F. When hair is assumed to be the object to be measured, the width W of the contact end 41 is preferable. ３ The width is preferably 10 to 30 μm. Multiple fibers F may be inserted into the fiber guide 30. Even in this case, the width W of the contact end 41 is also acceptable. ３ If the contactor is made sufficiently smaller than the diameter of the fiber F, only one fiber F guided to the bottom 34 of the fiber guide 30 will come into contact with the contactor 40. This allows for the selective measurement of a single fiber F. Furthermore, by selectively measuring a single fiber F, it is possible to capture the changes in the texture of that fiber F depending on its position. For example, it is possible to capture how damage spreads from the root to the tip of the hair.

[0028] The length of the fiber guide 30 in the x-axis direction is not particularly limited. For example, the length of the fiber guide 30 is five times or more the diameter of the fiber F. When hair is assumed to be the object to be measured, the length of the fiber guide 30 is, for example, 400 μm or more.

[0029] The amount P protruding from the bottom 34 of the contact end 41 is preferably 0.01 to 0.2 times the diameter of the fiber F. When hair is assumed to be the object to be measured, the amount P protruding from the contact end 41 is preferably 1 to 15 μm. If the fiber sensor AA has a plurality of measuring units 10, the amount P protruding from the contact end 41 may be set to the same amount in each of the multiple measuring units 10, or it may be set to a different amount in each unit.

[0030] When the fiber F is pressed against the contact element 40, the contact element 40 is displaced in the x-axis direction. When the fiber sensor AA is scanned along the fiber F in this state, the contact element 40 is displaced in the z-axis direction due to frictional force. A displacement detector 60 is provided to detect this displacement of the contact element 40. The displacement detector 60 can detect the displacement of the contact element 40 relative to the frame 20 in the x-axis and z-axis directions.

[0031] As shown in Figure 4, the displacement detector 60 is provided on the support 50. The displacement detector 60 consists of an x-direction displacement detector 61 that detects the displacement of the contactor 40 in the x-axis direction and a z-direction displacement detector 62 that detects the displacement of the contactor 40 in the z-axis direction.

[0032] The x-direction displacement detector 61 consists of first and second strain detection elements 63 and 64 that detect the strain of the beam 51. Piezoresistive elements can be used as the first and second strain detection elements 63 and 64. Piezoresistive elements can be formed on the surface of a semiconductor substrate by integrated circuit manufacturing processes such as impurity diffusion and ion implantation, and metal wiring formation technology.

[0033] First and second strain detection elements 63 and 64 are arranged on the surface of one of the multiple beams 51 that make up the support 50. Both the first and second strain detection elements 63 and 64 are arranged on the surface of the beam 51 near the first end that connects to the frame 20. The first strain detection element 63 is arranged along one side of the beam 51, and the second strain detection element 64 is arranged along the other side.

[0034] As shown in Figure 4, when the contact element 40 is displaced in the positive x-axis direction, strain is generated in the beam 51. In this case, if the first and second strain detection elements 63 and 64 are made of materials exhibiting a positive piezoelectric resistance coefficient, the resistance of the first strain detection element 63 will increase due to tensile stress, and the resistance of the second strain detection element 64 will decrease due to compressive stress. Conversely, when the contact element 40 is displaced in the negative x-axis direction, the resistance of the first strain detection element 63 will decrease due to compressive stress, and the resistance of the second strain detection element 64 will increase due to tensile stress.

[0035] A strain detection circuit for detecting the strain of the beam 51 is formed on the surface of the fiber sensor AA. The strain detection circuit for detecting strain due to displacement in the positive x-axis direction is a circuit that connects first and second strain detection elements 63 and 64 in series, applies a voltage Vsup across both ends, and reads the voltage Vout between the first strain detection element 63 and the second strain detection element 64. The voltage Vout changes due to the differential between the first and second strain detection elements 63 and 64. By reading the voltage Vout, the amount of strain in the beam 51 can be detected. As a result, the x-direction displacement detector 61 can detect the displacement of the contact element 40 in the x-axis direction.

[0036] The z-direction displacement detector 62 consists of third and fourth strain detection elements 65 and 66 that detect the strain of the beam 51. Piezoresistive elements can be used as the third and fourth strain detection elements 65 and 66.

[0037] On the surface of one of the plurality of beams 51 that make up the support 50, a third strain detection element 65 is formed near the first end connected to the frame 20. Also, on the surface of another beam 51, a fourth strain detection element 66 is formed near the second end connected to the contact 40.

[0038] When the contact 40 is displaced in the positive z-axis direction, strain occurs in the beam 51. At this time, if the third and fourth strain detection elements 65 and 66 are made of a material showing a positive piezoresistive coefficient, the resistance of the third strain detection element 65 decreases due to compressive stress, and the resistance of the fourth strain detection element 66 increases due to tensile stress. Conversely, when the contact 40 is displaced in the negative z-axis direction, the resistance of the third strain detection element 65 increases due to tensile stress, and the resistance of the fourth strain detection element 66 decreases due to compressive stress.

[0039] The strain detection circuit that detects the strain due to the displacement in the positive z-axis direction is a circuit that connects the third and fourth strain detection elements 65 and 66 in series, applies a voltage Vsup to both ends, and reads the voltage Vout between the third strain detection element 65 and the fourth strain detection element 66. The voltage Vout changes due to the differential of the third and fourth strain detection elements 65 and 66. By reading the voltage Vout, the amount of strain of the beam 51 can be detected. Thereby, the z-axis direction displacement of the contact 40 can be detected by the z-direction displacement detector 62.

[0040] Note that the displacement detector 60 is not limited to a piezoresistive element. The distance between the contact 40 and the frame 20 changes due to the displacement of the contact 40. Utilizing this, the displacement detector 60 may be configured to detect the capacitance between the contact 40 and the frame 20.

[0041] The displacement detector 60 may be configured to measure the displacement of the contact 40 in either the x-axis direction or the z-axis direction. As will be described later, fine irregularities on the fiber surface are measured from the displacement of the contact 40 in the x-axis direction, and the frictional force of a minute area on the fiber surface is measured from the displacement in the z-axis direction. When it suffices to measure the fine irregularities on the fiber surface, the displacement detector 60 may be configured to measure only the displacement of the contact 40 in the x-axis direction. Also, when it suffices to measure the frictional force of a minute area on the fiber surface, the displacement detector 60 may be configured to measure only the displacement of the contact 40 in the z-axis direction.

[0042] The fiber sensor AA can be manufactured, for example, by processing an SOI substrate according to the following procedure. Here, the SOI substrate has a three-layer structure of a support substrate (silicon), an oxide film layer (silicon dioxide), and an active layer (silicon), and its thickness is, for example, 350 μm.

[0043] First, the substrate is cleaned and subjected to oxidation treatment to form a surface oxide film on the active layer. Next, the surface oxide film is processed to form a diffusion layer pattern that becomes a circuit portion, and phosphorus diffusion is performed. Next, a piezoresistive element is formed by ion implantation of phosphorus and thermal annealing. Next, a chromium thin film is sputtered on the back surface of the substrate, and the chromium thin film is processed into a pattern for releasing the movable structure portion (contact 40 and support 50). Next, the surface oxide film is removed, and etching is performed by ICP-RIE to form the movable structure portion. After filling and protecting the periphery of the formed movable structure portion with a resist, the back surface is etched by ICP-RIE. Finally, the intermediate oxide film and the resist are removed to release the movable structure portion.

[0044] Note that the manufacturing method of the fiber sensor AA is not limited to semiconductor micromachining technology. For example, the whole or part of the fiber sensor AA may be formed by a modeling technology using a three-dimensional printer.

[0045] Next, a method for measuring fibers using the fiber sensor AA will be explained. First, tension is applied to the fiber F, which is the object to be measured, to straighten it out. Then, as shown in Figure 5, the fiber F is inserted into the fiber guide 30 of the fiber sensor AA. When the fiber sensor AA is pressed against the fiber F, the fiber F moves along the wall surface of the fiber guide 30 and is guided to the bottom 34. The fiber F positioned at the bottom 34 of the fiber guide 30 comes into contact with the contact end 41 of the contact element 40.

[0046] Next, while maintaining the contact end 41 in contact with the fiber F, the fiber sensor AA is scanned along the axial direction of the fiber F. The fiber F inserted into the fiber guide 30 is guided by the tapered end portion 33 to a position where it contacts the contact element 40. Because it is easy to maintain the state in which the fiber F is pressed against the contact element 40, the texture of the fiber F can be measured with a simple operation of inserting the fiber F into the fiber guide 30 and scanning the fiber sensor AA. For example, it can be measured with an action similar to combing hair with a comb.

[0047] As shown in Figure 6, when scanning the fiber sensor AA along the fiber F, it is preferable to tilt the main surface of the fiber sensor AA around the y-axis with respect to the axial direction of the fiber F. The contactor 40, formed from a semiconductor substrate, has a certain thickness (for example, 50 μm). On the other hand, the spacing between hair cuticles is 5 to 20 μm, which is smaller than the thickness of the contactor 40. If the contactor 40 is positioned perpendicular to the axial direction of the hair, the entire 50 μm thick contact end 41 will be in contact with the hair, making it impossible to accurately measure the irregularities of the cuticle. By tilting the fiber sensor AA with respect to the fiber F, only the corners of the contact end 41 will be in contact with the fiber F, thus reducing the contact area. As a result, the texture of the fiber F can be measured with high spatial resolution. For example, the irregularities of the hair cuticle can be measured accurately.

[0048] The angle of the main surface of the fiber sensor AA around the y-axis with respect to the plane perpendicular to the axis of fiber F is defined as the inclination angle θ of the fiber sensor AA. The inclination angle θ is preferably 5 to 15°.

[0049] Furthermore, if the cross-sectional shape of the contact element 40 can be made pointed at the tip, such as when the fiber sensor AA is formed by a 3D printer, then it is not necessary to tilt the fiber sensor AA relative to the fiber F.

[0050] When the fiber sensor AA is scanned along the fiber F, the contact element 40 is displaced in the x-axis direction along the surface irregularities of the fiber F. Furthermore, the contact element 40 is displaced in the z-axis direction due to the frictional force generated between the contact end 41 and the fiber F. Based on this displacement, the fine irregularities and frictional force in minute areas of the fiber surface can be measured.

[0051] Figure 7 shows examples of various signals obtained from the fiber sensor AA by the above operation. In graph (1), the horizontal axis is time, and the vertical axis is the displacement of the contactor 40 in the x-axis direction detected by the x-direction displacement detector 61. When the fiber sensor AA is scanned along the fiber F at a constant speed, the horizontal axis is equivalent to the axial position coordinate of the fiber F. The displacement of the contactor 40 in the x-axis direction represents the amount of surface irregularities of the fiber F. Therefore, graph (1) reproduces the surface shape (spatial waveform) of the fiber F.

[0052] Graph (2) shows time on the horizontal axis and the z-axis displacement of the contactor 40 detected by the z-direction displacement detector 62 on the vertical axis. The z-axis displacement of the contactor 40 represents the frictional force generated between the contactor 40 and the fiber F. Here, since the contact area of ​​the contactor 40 with the fiber F is small, the z-axis displacement of the contactor 40 represents the frictional force in a minute region.

[0053] The coefficient of dynamic friction μ of a minute region on the surface of the fiber F can be determined from the displacement of the contactor 40 in the x-axis and z-axis directions. Since the elastic modulus of the support 50 is known, the vertical load fx acting on the contactor 40 can be calculated from the displacement of the contactor 40 in the x-axis direction. In addition, the frictional force fz acting on the contactor 40 can be calculated from the displacement of the contactor 40 in the z-axis direction. According to the following equation (1), the coefficient of dynamic friction μ of a minute region on the surface of the fiber F can be calculated from the vertical load fx and the frictional force fz.

[0054] As described above, by measuring the displacement of the contactor 40 in the x-axis and z-axis directions, the texture of the fiber F, i.e., the fine irregularities and frictional force of minute areas, can be measured.

[0055] As shown in Figure 1, the fiber sensor AA of this embodiment has multiple measuring units 10. Therefore, the texture of multiple fibers F can be measured simultaneously. The amount of protrusion P of the contact end 41 may be set to different amounts in each of the multiple measuring units 10. The larger the amount of protrusion P of the contact end 41, the larger the vertical load fx that can be applied from the contactor 40 to the fiber F. Since multiple fibers F can be measured at once with multiple contactors 40 with different amounts of protrusion P, measurement results for multiple load ranges can be obtained at once.

[0056] The appropriate load range for measurement varies depending on the type of fiber F. For example, it is difficult to predict the appropriate load range for yarn. Even in such cases, by performing measurements at multiple load ranges, it is possible to obtain measurement results at the appropriate load range.

[0057] Furthermore, measurement results across multiple load ranges can be used, for example, to evaluate the dryness / moisture sensation of fiber F. The evaluation of dryness / moisture sensation is disclosed in Japanese Patent Publication No. 2024-93652. Dryness / moisture sensation is a sensation that occurs in human skin, and it is the feeling that an object in contact with the skin is dry or moist. Dryness / moisture sensation can be evaluated using the difference between the dynamic friction coefficient in the low load range and the dynamic friction coefficient in the high load range as an indicator. By performing measurements across multiple load ranges, the dynamic friction coefficient in the low load range and the dynamic friction coefficient in the high load range can be obtained simultaneously, and the dryness / moisture sensation can be used for evaluation.

[0058] [Second Embodiment] Next, a fiber sensor BB according to the second embodiment will be described. As shown in Figure 8, the basic structure of the fiber sensor BB of this embodiment is the same as that of the fiber sensor AA according to the first embodiment. The fiber sensor BB is flat overall. The fiber sensor BB has a plurality of measuring units 10. Each measuring unit 10 has a frame 20, a fiber guide 30, a contact element 40, and a support 50. The measuring unit 10 also has a displacement detector 60 (not shown).

[0059] As shown in Figure 9, in this embodiment, the bottom 34 of the fiber guide 30 is positioned at the shear center O of the support 50. The support 50, which is composed of multiple beams 51, is considered as a single structure, and an external force is assumed to be applied to the support 50 in the z-axis direction. In this case, the point at which the shear force is applied without causing torsion in the support 50 is called the shear center O. When the shear force acts at the shear center O, only bending deformation occurs in the support 50, and no torsional deformation occurs.

[0060] The support 50 of this embodiment consists of a plurality of beams 51. Each beam 51 is arranged along the y-axis. The plurality of beams 51 are arranged in a line along the x-axis. In addition, beams 51 are arranged on both the left and right sides of the contactor 40. Since the shape of the support 50 is symmetrical, the shear center O of the support 50 is located at the geometric center along the y-axis. If all beams 51 have the same length and width (i.e., the same elastic modulus) and are arranged at equal intervals along the x-axis, the shear center O of the support 50 is located at the geometric center along the x-axis. However, if beams 51 with different elastic moduli are mixed, or if the beams 51 are not arranged at equal intervals, the shear center O of the support 50 will be located at a position offset from the geometric center along the x-axis.

[0061] The bottom 34 of the fiber guide 30 is the position where the frictional force generated between the fiber F and the contactor 40 acts in the z-axis direction. Therefore, if the bottom 34 of the fiber guide 30 is positioned at the shear center O of the support 50, the frictional force will act at the shear center O.

[0062] As shown in Figure 10(A), in the first embodiment of the fiber sensor AA, the bottom 34 of the fiber guide 30 is positioned away from the shear center O of the support 50 in the x-axis direction. Therefore, when the frictional force generated between the fiber F acts on the contact end 41, a torsional moment about the y-axis is generated in the support 50, causing the support 50 to twist. This torsional deformation is reflected in the resistance values ​​of the first and second strain detection elements 63 and 64 that constitute the x-direction displacement detector 61 (see Figure 4). Therefore, it becomes a factor in the measurement error of the displacement of the contactor 40 in the x-axis direction (amount of surface irregularities of the fiber F).

[0063] In contrast, as shown in Figure 10(B), in this embodiment, the fiber sensor BB has the bottom 34 of the fiber guide 30 positioned at the shear center O of the support 50. Therefore, the frictional force generated between the fiber F guided to the bottom 34 of the fiber guide 30 and the contact 40 acts on the shear center O of the support 50. This suppresses torsional deformation of the support 50 and does not affect the output of the x-direction displacement detector 61. As a result, the displacement of the contact 40 in the x-axis direction, that is, the amount of surface irregularities of the fiber F, can be measured with high accuracy.

[0064] Furthermore, the position of the bottom 34 of the fiber guide 30 does not have to precisely coincide with the shear center O of the support 50. It is sufficient that the measurement accuracy of the displacement of the contactor 40 in the x-axis direction is within an acceptable range, and the position of the bottom 34 of the fiber guide 30 may be slightly off from the shear center O of the support 50. In this specification, even in such cases, the bottom 34 of the fiber guide 30 is positioned at the shear center O of the support 50.

[0065] As shown in Figure 9, the support 50 of this embodiment consists of a plurality of beams 51. Each beam 51 is arranged along the y-axis, and the plurality of beams 51 are arranged in a line along the x-axis. In the case of a support 50 with such a configuration, the position of its shear center O in the x-axis direction is between the two outermost beams 51A and 51B among the plurality of beams 51. Therefore, the position of the bottom 34 of the fiber guide 30 in the x-axis direction should be at least between the two outermost beams 51A and 51B among the plurality of beams 51.

[0066] In this manner, the frictional force generated between the fiber F guided to the bottom 34 of the fiber guide 30 and the contact element 40 acts on the shear center O of the support 50 or its vicinity, thereby suppressing torsional deformation of the support 50. As a result, the displacement of the contact element 40 in the x-axis direction can be measured with high accuracy.

[0067] Furthermore, the fiber guide 30 is embedded within the structure of the support 50. As a result, the x-axis dimension of the measuring section 10 can be shortened, and the fiber sensor BB can be miniaturized. By miniaturizing the fiber sensor BB, it is also possible to increase the yield of fiber sensor BB from the semiconductor substrate.

[0068] Next, examples will be described. A fiber sensor BB having the configuration shown in FIG. 8 was fabricated by processing a p-type SOI substrate. The SOI substrate has a three-layer structure of a support substrate (thickness: 300 μm), an oxide film layer (thickness: 0.5 μm), and an active layer (thickness: 50 μm). The width W of the opening 31 of the fiber guide 30 １ is 300 μm, and the width W of the bottom 34 of the fiber guide 30 ２ is 60 μm, and the width W of the contact end 41 ３ is 20 μm. The fiber sensor BB has three measurement units 10. The protrusion amounts P of the contact ends 41 are 2 μm, 4 μm, and 10 μm, respectively.

[0069] (Sensitivity evaluation) A sensitivity evaluation test of the fabricated fiber sensor BB was conducted. A micro mechanical tester (FemtoTools FT-MTA03) having a force resolution in the nN range was used for the test. The probe of the micro mechanical tester was pressed against the contact 40 in the x-axis direction to obtain the displacement of the contact 40 in the x-axis direction and the output voltage Vout of the x-direction displacement detector 61. Also, the probe of the micro mechanical tester was pressed against the contact 40 in the z-axis direction to obtain the load in the z-axis direction and the output voltage Vout of the z-direction displacement detector 62.

[0070] FIG. 11(A) is a graph showing the relationship between the displacement of the contact 40 in the x-axis direction and the output voltage Vout of the x-direction displacement detector 61. The sensitivity of the displacement in the x-axis direction was 117.1 mV / μm. FIG. 11(B) is a graph showing the relationship between the load in the z-axis direction applied to the contact 40 and the output voltage Vout of the z-direction displacement detector 62. The sensitivity of the load in the z-axis direction was 66.7 mV / mN. From the above tests, it was confirmed that the fiber sensor BB has sufficient sensitivity.

[0071] (Inclination angle) A hair (cuticle interval: about 10 μm, step: 0.5 μm or less) was fixed to a uniaxial stage under a tension of 0.1 N. The hair was inserted into the fiber guide 30 of the fiber sensor BB, and the fiber sensor BB was fixed and scanned by moving the hair in the axial direction. Here, the scanning distance was 5 mm and the scanning speed was 2 mm / second.

[0072] Measurements were performed with the fiber sensor BB tilted at two different angles relative to the hair: 0° and 10°. Figure 12(A) shows a graph of the hair surface shape measured with a tilt angle of 0°. Figure 12(B) shows a graph of the hair surface shape measured with a tilt angle of 10°.

[0073] The contact element 40 of the fiber sensor BB is formed of an active layer with a thickness of 50 μm. Therefore, the thickness of the contact end 41 is 50 μm. In contrast, the cuticle of hair has a spacing of about 10 μm and a step difference of 0.5 μm or less. When the tilt angle θ is set to 0°, the thickness of the contact end 41 reduces the spatial resolution, so the waveform of the surface shape becomes unclear, as shown in Figure 12(A). On the other hand, when the tilt angle θ is set to 10°, the corner of the contact end 41 comes into contact with the surface of the hair, thus increasing the spatial resolution. From Figure 12(B), it can be seen that the waveform of the surface shape becomes clear. In addition, a step difference of about 0.5 μm at approximately 10 μm intervals was confirmed, confirming that the shape of the cuticle was being measured.

[0074] (Scanning Direction) Next, measurements were taken when the fiber sensor BB was scanned from the root to the tip of the hair, and when it was scanned from the tip to the root. Figure 13(A) shows the surface shape and frictional force waveform when scanned from the root to the tip of the hair. Figure 13(B) shows the surface shape and frictional force waveform when scanned from the fingertip to the root of the hair. Compared to scanning from the root to the tip of the hair, the range of frictional force fluctuation is larger when scanning from the fingertip to the root of the hair. This is thought to be because scanning from the fingertip to the root of the hair is done against the direction of the cuticle. In fact, even with human fingers, resistance is felt when stroking hair from the fingertip to the root than when stroking it from the root to the tip. In this way, the fiber sensor BB can reproduce the human sense of touch. This characteristic makes it possible to quantitatively measure the texture and degree of damage of hair.

[0075] (Fiber Guide) Next, the function of the fiber guide 30 was evaluated. While photographing the fiber sensor BB with a camera, a single hair was inserted through the opening 31 of the fiber guide 30. As a result, it was confirmed that the hair moved along the wall surface of the fiber guide 30 and was guided to the bottom 34.

[0076] Next, six strands of hair were inserted into the fiber guide 30, and the fiber sensor BB was scanned along the hair bundle to perform measurements. Figure 14 shows a graph of the surface shape obtained from the measurement. Steps of approximately 0.5 μm were observed at intervals of approximately 10 μm, indicating that the shape of the cuticle was measured. From this, it was confirmed that even when multiple strands of hair were inserted into the fiber guide 30, a single strand of hair could be selectively measured.

[0077] (Simultaneous Measurement) Next, three strands of hair were measured simultaneously using the three measurement units 10 of the fiber sensor BB. Figure 15(A) shows the surface shape and frictional force waveform obtained by the measurement unit 10 with a contact end 41 protrusion amount P of 2 μm. Figure 15(B) shows the surface shape and frictional force waveform obtained by the measurement unit 10 with a contact end 41 protrusion amount P of 4 μm. Figure 15(C) shows the surface shape and frictional force waveform obtained by the measurement unit 10 with a contact end 41 protrusion amount P of 10 μm. It was confirmed that by measuring hair with multiple measurement units 10 with different contact end 41 protrusion amounts P, measurements can be taken at multiple load ranges simultaneously.

[0078] (Measurement of yarn) Next, the object to be measured was changed to yarn and measurements were taken. The yarn used was made of polyester. Multiple polyester fibers with a diameter of approximately 4 μm were twisted together to form strands, and multiple strands were twisted together to form a yarn with a diameter of approximately 240 μm.

[0079] Figure 16 shows a graph of the surface shape obtained by measurement. It can be seen that large peaks appear at intervals of approximately 1,400 μm. These large peaks correspond to the spacing of the strand twists. In addition, numerous small peaks are observed between the large peaks. These small peaks correspond to the polyester fibers that make up the strand. From the above, it was confirmed that the surface shape of yarn can be measured with high resolution using the fiber sensor BB.

[0080] AA, BB Fiber Sensor 10 Measuring section 20 Frame 30 Fiber guide 31 Opening 32 Introduction section 33 End section 34 Bottom section 40 Contact element 41 Contact end 50 Support 51 Beam 60 Displacement detector

Claims

1. A fiber sensor comprising one or more measuring units, wherein the measuring unit comprises: a flat plate-shaped frame having a main surface parallel to the x-y plane when three-dimensional spatial coordinates are defined by mutually orthogonal x-axis, y-axis, and z-axis; a fiber guide having an introduction portion and an end portion following the introduction portion, which is a notch formed in the frame along the x-axis and includes an opening located on the side surface of the frame; a contactor having a contact end that contacts a fiber inserted into the fiber guide; a support that supports the contactor so as to be displaceable with respect to the frame in the x-axis direction and / or the z-axis direction; and a displacement detector that detects the displacement of the contactor with respect to the frame in the x-axis direction and / or the z-axis direction, wherein the contact end protrudes from the bottom of the end portion to the extent that it does not reach the introduction portion when no external force is applied to the contactor.

2. The fiber sensor according to claim 1, characterized in that the end portion of the fiber guide is tapered toward the bottom portion.

3. The fiber sensor according to claim 1, characterized in that the width of the opening of the fiber guide in the y-axis direction is three times or more the diameter of the fiber.

4. The fiber sensor according to claim 1, characterized in that the width of the contact end in the y-axis direction is 0.1 to 0.5 times the diameter of the fiber.

5. The fiber sensor according to claim 1, characterized in that the bottom of the fiber guide is positioned at the shear center of the support when an external force is applied to the support in the z-axis direction.

6. The support consists of a plurality of beams arranged in line in the x-axis direction, each of the plurality of beams having a first end arranged along the y-axis and connected to the frame, and a second end connected to the contactor, and the position of the bottom of the fiber guide in the x-axis direction is between the two outermost beams of the plurality of beams, characterized in that the fiber sensor according to claim 1.

7. The fiber sensor according to claim 1, characterized in that the plurality of measuring units are arranged in line in the y-axis direction, and the amount of protrusion of the contact end from the bottom is set to be different for each unit.

8. A fiber measurement method using a fiber sensor according to any one of claims 1 to 7, characterized in that the fiber sensor is scanned along the fiber while the contact end is in contact with the fiber, with the main surface of the fiber sensor inclined about the y-axis with respect to the axial direction of the fiber.

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