JP6842162B2 - Plane sensor and cloth heater - Google Patents

Description

The present invention relates to a planar sensor and a cloth heater, and more particularly to a planar sensor and a cloth heater woven with a conductive yarn.

Cloth heaters that expand and contract freely are in increasing demand in the market. The applicant has been researching cloth heaters to meet the demand in the market. The cloth heater proposed in Patent Document 1 was obtained in the course of the research conducted by the applicant, and has an electrode portion provided on the cloth. The fabric is knitted so as to form a plurality of loops of conductive threads and entangle the loops of adjacent conductive threads. The electrode portion is composed of an electrode thread and is provided on the fabric at intervals. The electrode thread has at least one or a plurality of conductive strands and a first form in which the conductive thread is composed of a core wire made of fibers and a metal layer or metal foil covering the surface of the core wire. It can be roughly divided into a second form composed of a set line.

International release WO2013 / 085051

As a result of further research on the properties of the above-mentioned cloth heater, the applicant has found that in the cloth heater made of knitted fabric, the electric resistance value of the cloth decreases when the temperature of the cloth rises, and the temperature of the cloth decreases. It was found that the electrical resistance of the fabric increased in some cases. In general, the electric resistance value of a metal increases as the temperature rises, and the electric resistance value also decreases as the temperature decreases. However, the above-mentioned cloth heater showed a phenomenon completely opposite to the common general technical knowledge. The applicant has earnestly studied a cloth heater showing a phenomenon opposite to the common general technical knowledge, and completed the present invention by utilizing the phenomenon.

An object of the present invention is to provide a planar sensor and a cloth heater utilizing the phenomenon that the electric resistance value of the cloth decreases when the temperature of the cloth rises and the electric resistance value of the cloth rises when the temperature of the cloth decreases. To provide.

(1) The planar sensor according to the present invention is made of a fabric in which a plurality of loops are formed of conductive threads and the plurality of the conductive threads are entwined with each other and woven, and an electric current flows through the conductive threads. The temperature of the fabric rises and the form of entanglement of the adjacent conductive threads changes, the current path flowing through the fabric is shortened, or the contact between the loops increases and the electric resistance value of the fabric decreases. It is characterized by doing.

According to the present invention, when the temperature of the fabric rises, the form of entanglement of the conductive threads changes, the current path flowing through the fabric is shortened, or the contact between loops increases and the electric resistance value of the fabric increases. descend. On the contrary, when the temperature of the fabric is lowered, the entangled form of the adjacent conductive yarns is restored, the current path is lengthened, or the contact between the loops is reduced and the electric resistance value of the fabric is increased. As a result, the fabric itself functions as a sensor for the electrical resistance value without using a separate sensor.

In the planar sensor according to the present invention, the direction in which the current flows is the course direction in which the plurality of loops formed for each conductive thread are connected.

According to the present invention, since the direction of current flow is the course direction in which a plurality of loops formed for each conductive thread are connected, the current path is shortened when the loops come into contact with each other between adjacent conductive threads. The current is bypassed and the electrical resistance is reduced.

In the planar sensor according to the present invention, the conductive yarn is formed by twisting a plurality of filament wires having a metal conductor coated on the outer circumference of the core wire.

According to the present invention, as the conductive yarn, a filament wire having a metal conductor coated on the outer circumference of the core wire is used, so that the fabric can be stretchable and stretchable. It becomes a smooth surface sensor.

In the planar sensor according to the present invention, a controller is connected to the fabric, and the controller detects the electric resistance value of the fabric and the fabric based on the electric resistance value detected by the detecting means. It is provided with a control means for lowering or increasing the voltage applied to the device or stopping or starting the application of the voltage.

According to the present invention, as described above, the detection means for detecting the electric resistance value of the fabric and the control means for lowering or increasing the voltage applied to the fabric or stopping or starting the application of the voltage are provided. Therefore, when the temperature of the fabric reaches a predetermined temperature, the electric resistance value decreases, and the current flow improves, the temperature can be controlled so as not to rise too much. On the other hand, when the temperature of the fabric drops too much and the electric resistance value rises, it is possible to control the temperature by passing an electric current. Therefore, the planar sensor can be used as the sensor of the safety device.

(2) The cloth heater according to the present invention is composed of a cloth in which a plurality of loops are formed of conductive threads and the plurality of said conductive threads are entwined with each other and woven together, and an electrode thread, and is spaced between the cloths. The entangled form of the adjacent conductive yarns changes as the current flows through the conductive yarns and the temperature of the fabric rises, and the conductive yarns flow through the fabric. It is characterized in that the path of the electric current is shortened or the contact between the loops is increased and the electric resistance value of the fabric is lowered.

According to the present invention, when the temperature of the fabric rises, the form of entanglement of the conductive threads changes, the current path flowing through the fabric is shortened, or the contact between loops increases and the electric resistance value of the fabric increases. descend. On the contrary, when the temperature of the fabric is lowered, the entangled form of the adjacent conductive yarns is restored, the current path is lengthened, or the contact between the loops is reduced and the electric resistance value of the fabric is increased. As a result, the cloth itself can be used as a cloth heater that functions as a sensor for the electric resistance value without using a separate sensor.

According to the present invention, the temperature of the fabric is prevented from rising above a predetermined temperature or falling too much based on the specific phenomenon that the electrical resistance value of the fabric decreases as the temperature of the fabric rises. A planar sensor that can be used can be provided. Further, it is possible to provide a cloth heater in which such a cloth functions as a surface sensor.

It is a block diagram which shows the system model which operates the planar sensor which concerns on this invention. It is an enlarged view which showed the stitch of the conductive thread which constitutes the cloth | fabric of a planar sensor as a model. It is the drawing which showed the conductive thread as a model, (A) is the enlarged sectional view of the filament wire which comprises the conductive thread, (B) is the perspective view which showed the conductive thread as a model. It is explanatory drawing for demonstrating that the entanglement form of the loop formed in the conductive yarn changes as the temperature of a cloth rises. It is explanatory drawing for demonstrating that the path through which an electric current flows changes as the form of entanglement of a loop changes. It is a graph which shows the relationship between the temperature of a cloth and the electric resistance value as a model. It is a graph which shows the result of having measured the relationship between the temperature of a cloth, and the electric resistance value.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the present invention includes the invention of the same technical idea as the embodiment described below and the embodiment described in the drawings, and the technical scope of the present invention is limited to the description of the embodiment and the description of the drawings. Not a thing.

[Basic configuration]
The planar sensor 1 according to the present invention is composed of a fabric 2 in which a plurality of loops 20 are formed of conductive threads 10 and a plurality of conductive threads 10 are entwined with each other and woven. In the planar sensor 1, does the entanglement form of the adjacent conductive threads 10 change as the current flows through the conductive threads 10 and the temperature of the fabric 2 rises, and the current path flowing through the fabric 2 is shortened? Or, the contact between the loops 20 increases and the electric resistance value of the fabric 2 decreases. Further, the cloth heater 1A according to the present invention is composed of a cloth 2 in which a plurality of loops 20 are formed of conductive threads 10 and the plurality of conductive threads 10 are entwined with each other and woven together, and an electrode thread. It is provided with electrode portions 3 provided at intervals of 2. In the cloth heater 1A, as the current flows through the conductive thread 10 and the temperature of the cloth 2 rises, the form of entanglement of the conductive threads 10 constituting the cloth 2 changes, and the current path flowing through the cloth 2 is shortened. Alternatively, the contact between the loops 20 increases and the electric resistance value of the fabric 2 decreases.

In such a planar sensor 1 and a cloth heater 1A, the cloth 2 is a knitted conductive yarn 10 in which a metal layer 12 or a filament wire 15 coated with a metal foil is twisted. In such a fabric 2, heat is generated by utilizing the electric resistance of the metal layer 12 or the metal foil covering the filament wire.

The electrical resistance of metals increases as the temperature rises. Based on this common general knowledge, as the temperature rises, the electrical resistance of the metal layer 12 or the metal foil naturally increases, making it difficult for current to flow, and the temperature of the fabric 2 decreases. Further, when the temperature decreases, the electric resistance of the metal layer 12 or the metal foil naturally decreases, the current easily flows, and the temperature of the fabric 2 increases. However, when the temperature of the fabric 2 in which the conductive yarn 10 is woven as described above rises when a voltage is applied, the electrical resistance of the fabric 2 surprisingly decreases, while when the voltage is stopped and the temperature drops. The electrical resistance of the fabric 2 has increased. In this phenomenon, when the temperature rises, the fabric 2 contracts, the contact between the loops 20 of the adjacent conductive threads 10 increases, the current path is shortened, and when the temperature decreases, the contraction of the fabric 2 returns to the original state, and the fabrics 2 are adjacent to each other. It is presumed that this is based on the fact that the contact between the loops 20 of the conductive threads 10 is reduced and the current path is lengthened as before. The present invention utilizes a phenomenon in which the electric resistance value of the fabric 2 decreases when the temperature of the fabric 2 rises, and the electric resistance value of the fabric 2 increases when the temperature of the fabric 2 decreases. It is an object of the present invention to provide a planar sensor 1 that can be used so that the temperature of the fabric 2 does not rise above a predetermined temperature and the temperature of the fabric 2 does not drop too much.

If a conventionally known thermistor or thermal fuse is used for a thin and soft fabric 2, the size and hardness of the fabric 2 may be uncomfortable, and the thermistor or thermal fuse may be damaged by impact or refraction. However, in the planar sensor 1 and the cloth heater 1A according to the present invention, since the cloth itself functions as a sensor, it is not necessary to attach a solid object to the cloth 2 when a thin and soft cloth 2 is used, and there is no discomfort during use. .. In addition, there is no risk of destruction due to impact or refraction. Further, unlike the thermistor, it does not detect only the temperature at one point, but detects the electric resistance value of the entire fabric.

Hereinafter, specific configurations of the planar sensor 1 and the cloth heater 1A according to the present invention will be described. Since the basic configuration of the planar sensor 1 and the cloth heater 1A is the same, the planar sensor 1 will be described below as an example.

[Configuration example of surface sensor]
FIG. 1 shows a configuration example of a system model in which the planar sensor 1 operates. The planar sensor 1 of this configuration example has one piece of cloth 2 and electrode portions 3 provided on the cloth 2 at regular intervals. A controller 5 that applies a voltage and controls the applied voltage is connected to the electrode portion 3 by wiring 4. The electrode portions 3 are provided at two locations on the fabric 2. The electrode portions 3 provided at the two locations are provided at predetermined intervals. However, the electrode portions 3 may be provided at two or more locations as long as the function of the sensor is not impaired. Such an electrode portion 3 is formed, for example, by sewing an electrode thread. When the electrode thread is sewn into the fabric 2 to form the electrode portion 3, the electrode portion 3 is formed by, for example, a decorative sewing method so that the electrode thread is freely deformed according to the expansion and contraction of the fabric 2. Is preferable. When the electrode thread is decoratively sewn to form the electrode portion 3, the electrode portion 3 is deformed according to the expansion and contraction of the fabric 2. Such an electrode portion 3 is fixedly attached to the cloth 2, but is not limited to this, and can be detachably provided to the cloth 2.

<Fabric>
The fabric 2 constituting the surface sensor 1 is a knitted fabric. A knitted fabric is generally formed by connecting a plurality of loops 20 to a yarn and entwining the loops 20 of a plurality of adjacent yarns. As shown in FIG. 2, the planar sensor 1 is a knitted fabric formed by connecting loops 20 to conductive threads 10 and entwining loops 20 of a plurality of adjacent conductive threads 10.

The method of knitting the conductive yarn 10 is not particularly limited, and the conductive yarn 10 may be knitted by weft knitting or by knitting the conductive yarn 10 by warp knitting. Examples of the flat knitting include plain knitting, rib knitting (also referred to as milling knitting or rubber knitting), pearl knitting (also referred to as links knitting or garter knitting), and the like. Examples of the warp knitting include tricot knitting and atlas knitting. The method of knitting the conductive yarn 10 may be appropriately selected according to the application of the planar sensor 1 and the like. The present invention is characterized in that the fabric 2 is knitted by such a knitting method, and the fabric 2 knitted in this way changes the entangled form of the conductive yarn 10 when the temperature of the fabric 2 rises. (Shrinks), and conversely, when the temperature of the fabric 2 drops, the entangled form of the adjacent conductive threads 10 returns to the original form. The knitting method of the fabric 2 needs to cause such a morphological change, and if such a morphological change occurs, various knitting methods can be adopted.

The structure of the fabric 2 is not particularly limited as long as such a morphological change occurs, and various structures can be used. For example, a configuration in which only the conductive yarn 10 is knitted, one side is knitted with the conductive yarn 10, the other side is knitted with the fiber yarn, one side is knitted with the conductive yarn 10, the other side is knitted with the fiber yarn, and one side and the other side are knitted. A configuration in which an intermediate layer knitted with a fiber yarn is provided between the two, a configuration in which one surface and the other surface are knitted with a fiber yarn, and an intermediate layer knitted with a conductive yarn 10 is provided between one surface and the other surface, etc. Can be mentioned. Further, the fabric 2 may be configured such that a portion formed by knitting only the conductive thread 10 and a portion formed by knitting the fiber thread are connected in a plane. Further, every time several conductive yarns 10 are knitted, fiber yarns may be knitted regularly or irregularly. As the fiber yarn, an arbitrarily selected denier fiber yarn is used.

<Conductive thread>
The conductive thread 10 is composed of a plurality of filament wires 15 twisted together. The filament wire 15 is composed of a core wire 11 and a metal conductor provided on the outer periphery of the core wire 11. As shown in FIG. 3A, the filament wire 15 preferably has a core wire 11 formed of fibers and a metal layer 12 or a metal foil provided on the outer periphery of the core wire 11.

As the fiber, a fiber capable of causing a phenomenon peculiar to the present invention, in which the fabric 2 contracts due to the temperature rise and the electric resistance decreases, and the shrinkage of the fabric 2 returns to the original state and the electric resistance increases due to the temperature decrease, is used. Be done. Such fibers are arbitrarily selected from synthetic fibers and natural fibers. Examples of synthetic fibers include polyamide fibers and polyester fibers. Examples of the polyamide fiber include nylon, Kepler (registered trademark), Techneal (registered trademark) and the like. Examples of the polyester fiber include Tetron (registered trademark) and the like. As the natural fiber, one having the same properties as the above synthetic fiber can be used. Among the fibers, nylon is preferably used because it can satisfactorily cause a phenomenon peculiar to the present invention.

As shown in FIG. 3A, the metal layer 12 can be formed by plating (electroless or electrolysis), thin film deposition, sputtering, or the like. The material of the metal layer 12 is not particularly limited, but copper, a copper alloy, silver, a silver alloy, or the like is preferable. The metal foil is preferably processed into a strip shape, and is spirally wound in the length direction so as to cover the outer periphery of the core wire 11. The material of the metal foil is also not particularly limited, and copper, a copper alloy (for example, a copper alloy containing 0.3% by mass of tin) or the like is preferable. The conductive thread 10 is formed by twisting a plurality of filament wires 15 covered with a metal layer 12 or a metal foil as shown in FIG. 3 (B).

<Relationship between changes in the form of entanglement of conductive threads and current flow>
4 (A) and 4 (B) are diagrams modelally showing that the entangled form of the adjacent conductive threads 10 changes as the temperature rises and falls. Before the temperature rises when no voltage is applied to the fabric 2, the conductive threads 10 constituting the fabric 2 are loops 20 formed in the adjacent conductive threads 10 constituting the fabric 2, as shown in FIG. 4 (A). They are loosely intertwined with each other. Therefore, there is little contact between the loops 20 of the adjacent conductive threads 10. On the other hand, at the stage after the temperature rises when a voltage is applied to the cloth 2, the conductive threads 10 constituting the cloth 2 are in contact with the loops 20 of the adjacent conductive threads 10 as shown in FIG. 4 (B). Increase. This phenomenon occurs when the fibers, which are the core wires 11 of the conductive yarn 10, contract as the temperature rises, causing the fabric 2 to contract as a whole, and when the temperature decreases, the contracted fibers return to their original state. However, it occurs when the fabric 2 that has shrunk as a whole returns to its original state.

Regarding the change in the path through which the current flows when a voltage is applied to the cloth 2 to raise or lower the temperature of the cloth 2 and the form of entanglement between the loops 20 of the adjacent conductive threads 10 changes, refer to FIG. explain.

FIG. 5 shows a change when a voltage is applied in the course direction (X direction in the figure) in which a plurality of loops 20 formed for each conductive thread 10 are connected in one direction. When the voltage has just been applied, the temperature of the fabric 2 has not yet risen. When the temperature of the fabric 2 does not rise, the form of entanglement between the loops 20 of the adjacent conductive threads 10 does not change, and the contact between the loops 20 of the adjacent conductive threads 10 is small. In this case, the current flowing through the conductive threads 10 flows in the longitudinal direction of each conductive thread 10 as shown in FIG. 5 (A). Therefore, in each conductive thread 10, an electric resistance value corresponding to the length of the loop 20 formed in each conductive thread 10 is generated. On the other hand, the temperature of the fabric 2 rises as time passes after the voltage is applied to the fabric 2. When the temperature of the fabric 2 rises, the form of entanglement between the loops 20 of the adjacent conductive threads 10 changes, and the contact between the loops 20 of the adjacent conductive threads 10 increases. When the temperature of the fabric 2 rises, the current flowing through the conductive yarn 10 causes the fabric 2 to shrink due to the temperature rise and the contact between the loops 20 of the adjacent conductive yarns 10 increases. A short circuit occurs at the contact portion and the current path is shortened. Therefore, in each conductive thread 10, the electric resistance value corresponding to the length of the loop 20 formed in each conductive thread 10 decreases. Further, as the contact between the loops 20 of the adjacent conductive threads 10 increases, the electric resistance value of the fabric 2 decreases. After that, when the applied voltage is lowered or the voltage application is stopped, the temperature of the fabric 2 is lowered. When the temperature of the fabric 2 drops, the form of entanglement of the loops 20 of the adjacent conductive threads 10 returns from the state of FIG. 5 (B) to the original state shown in FIG. 5 (A), and the adjacent conductive threads return to the original state. The contact between the loops 20 of the 10 is reduced. In this case, as shown in FIG. 5A, the current flowing through the conductive threads 10 flows in the longitudinal direction of each conductive thread 10.

FIG. 6 is a model diagram of the relationship between the temperature of the fabric 2 and the electric resistance value of the conductive yarn 10. In FIG. 6, the horizontal axis represents the temperature of the fabric 2, and the vertical axis represents the electric resistance value of the conductive yarn 10. In FIG. 6, the temperature of the fabric 2 is changed in the range of 30 ° C. to 80 ° C. When the temperature of the fabric 2 starts to rise from 30 ° C., the electric resistance value of the conductive yarn 10 drops significantly. As the temperature of the fabric 2 rises, the decrease in the electric resistance value gradually becomes smaller. At that time, the electric resistance value continuously decreases. Speaking of this in terms of the rate of change in electrical resistance (also referred to as the rate of change in resistance), in the graph shown in FIG. 6, when the temperature of the fabric 2 is close to 30 ° C, the slope of the tangent line of the graph is large and the resistance The rate of change is large, and at a temperature close to 80 ° C., the slope of the tangent line of the graph is small and the rate of change in resistance is small. When the temperature is lowered, the opposite phenomenon occurs and the electric resistance value becomes high.

The case where the voltage is applied in the course direction of the stitches has been described above as an example. However, when the voltage is applied in the wale direction (Y direction) of the stitches as well, the electric resistance value decreases as the temperature rises, and the temperature drops. As a result, the electrical resistance value increases. From this, due to the same morphological change as described above, the contact between the loops of the adjacent conductive threads 10 increases and the electric resistance value decreases, or the contact between the loops of the adjacent conductive threads 10 decreases and the electric resistance value decreases. Is expected to increase.

<Controller>
The controller 5 is connected to the electrode portion 3 by the wiring 4. The controller 5 has a function as a power source for applying a voltage, a function as a detection unit for detecting the electric resistance value of the fabric 2, and a control unit for lowering or increasing the applied voltage or stopping or starting the application of the voltage. It has a function as. The controller 5 applies or stops a voltage as needed based on the relationship between the temperature measured in advance and the electric resistance value for each form of the fabric 2. For example, a voltage in the range of DC 1.0V or more and DC 25V or less is applied or the application is stopped.

The rate of change in resistance when the temperature rises or falls is represented by [rate of change in electrical resistance = ΔΩ / ΔT]. ΔT represents the amount of change in temperature, and ΔΩ represents the amount of change in the electrical resistance value when the temperature changes by ΔT.

The controller 5 controls the magnitude of the voltage applied to the fabric 2 and also controls whether or not the voltage is applied. This control is determined by how much the temperature of the fabric 2 is desired to be raised, or how much the temperature is lowered before the heating is to be started. The controller 5 sets an allowable temperature in advance so that when the temperature of the fabric 2 reaches a predetermined temperature (for example, 50 ° C.), the voltage applied to the fabric 2 is lowered or the voltage application is stopped. Then, when the temperature of the fabric 2 reaches a predetermined temperature (for example, 50 ° C.), the application of the voltage is controlled. Further, when the temperature of the fabric 2 drops to a predetermined temperature, the allowable temperature is set in advance so that the voltage applied to the fabric 2 is increased or the application of the voltage is restarted, and the temperature of the fabric 2 is raised. Controls the application of voltage when the temperature drops to a predetermined temperature.

These controls determine whether to apply a voltage based on the changed electrical resistance value or resistance change rate. As shown in the graph of FIG. 6 described above, the electric resistance value or the rate of change in resistance gradually decreases as the temperature of the fabric 2 rises. The controller 5 may have a storage unit, and the storage unit may have an electrical resistance value or a resistance change rate that lowers or increases the voltage applied to the fabric 2 or stops or starts the applied voltage in advance. It is remembered. When the electric resistance value or the resistance change rate matches the set value, the control unit of the controller 5 lowers or increases the voltage applied to the fabric 2, or stops or starts the applied voltage. The detection unit constitutes the detection means of the present invention, and the control unit constitutes the control means of the present invention. As described above, the planar sensor 1 can be used as a sensor of the safety device by its control.

The configuration example shown in FIG. 1 shows a system model for allowing the fabric 2 to function as the planar sensor 1. The planar sensor 1 according to the present invention includes, for example, sportswear, ski wear, work clothes, other general clothing, bed sheets, gloves, socks, supporters, mufflers, eye masks, kneelings, industrial heaters, and snow melting devices. Etc. can be applied. For example, when the planar sensor 1 is used for clothing, a small controller 5 can be connected to the electrode portion 3 of the planar sensor 1. The controller 5 controls the application of a voltage from the electrode portion 3 to the clothing.

Since the temperature of clothing rises when a voltage is applied, it can be used as winter clothes or the like. In this case, the controller 5 determines that the temperature of the clothes has reached the set temperature when the electric resistance value or the resistance change rate of the clothes decreases to a preset value, and lowers the voltage applied to the clothes. Stop applying voltage. On the other hand, if the voltage applied to the clothes is kept lowered or the voltage applied to the clothes is stopped, the temperature of the clothes is lowered. In that case, when the electrical resistance value or resistance change rate increases to a preset value due to the decrease in temperature, it is judged that the temperature of the clothes has dropped too much, and the voltage applied to the clothes is increased or the voltage is applied. Start. With such a sensor function, it can be operated as a planar sensor.

[Experimental example]
<Confirmation experiment>
An experiment was conducted to confirm that the electric resistance value of the cloth 2 decreases as the temperature of the cloth 2 rises. The experimental method and experimental results will be described below.

(Test pieces)
In this experiment, a conductive yarn 10 obtained by twisting a plurality of filament wires 15 obtained by coating nylon 66 with silver was used. As the test piece, a flat knitted double-sided knitted fabric using a conductive yarn 10 and a polyester yarn was used. The double-sided plain knit is a flat knit whose outer material is made of only conductive yarn 10 and whose lining is made of only polyester yarn, and both sides are connected by polyester yarn which is a connecting yarn. The course density of the plain knitted fabric was 14 courses / inch. The mesh length was 134 mm, the basis weight was 183 g / m ² , and the gauge was 18.3 G.

The conductive yarn 10 is a yarn in which the surface of nylon 66 yarn is coated with silver by sputtering. Nylon 66 has a raw yarn of 7.8 tex, and the filament wire 15 has a thickness of 10.2 tex.

(experimental method)
In the experiment, a voltage was applied to the test piece, and the relationship between the temperature of the test piece and the electric resistance value was measured. The temperature of the test piece was raised from 30 ° C. to 80 ° C., and the electric resistance value was measured each time the temperature was raised by 10 ° C. The electric resistance value was calculated based on the applied voltage value and current value. The voltage was a constant value of 1.0 V applied by a PSW30-36 type DC regulated power supply manufactured by GW INSTEK.

(Experimental result)
FIG. 7 shows the experimental results. As shown in FIG. 7, the electric resistance value was about 3.7Ω when the temperature was 30 ° C. As the temperature increased, the electrical resistance value gradually decreased from 3.7Ω. Specifically, when the temperature is 40 ° C, the electric resistance value is about 3.3Ω, when the temperature is 50 ° C, the electric resistance value is about 3.1Ω, and when the temperature is 60 ° C, the electric resistance value is about. It was 2.9Ω, and the electric resistance value was about 2.8Ω when the temperature was 70 ° C., and the electric resistance value was about 2.6Ω when the temperature was 80 ° C.

Further, as the temperature increased, the degree of decrease in the electric resistance value gradually decreased. That is, as the temperature rises, the rate of change in the electrical resistance value decreases.

<Comparative experiment>
The comparative experiments are the fluctuation of the electrical resistance value of the test piece when a tensile force is applied to the test piece, the fluctuation of the electrical resistance value of the test piece when a compressive force is applied to the test piece, and the test when the test piece is heated. The fluctuation of the electric resistance value of the piece and the heat shrinkage rate of the conductive thread 10 were measured, respectively. The test used was the same as the above confirmation experiment.

(experimental method)
(1) Fluctuations in electrical resistance due to tension (1.1) Experimental method In the tension test, the tension of JIS (JAPAN Industrial Standards) L1096 was carried out in an environment where the temperature was 25 ± 2 ° C and the humidity was 50 ± 5% RH. Strength and elongation were performed according to the A method (strip method). The test was carried out by grasping test sides having a width of 50 mm and a length of 300 mm at intervals of 200 mm, setting a tensile speed of 200 mm / min, and applying a voltage in the course direction. In the pulling mode, the tensile elongation was increased by 10%, and the tensile elongation was temporarily stopped at each elongation. Then, electrodes were attached in the length direction, the current value was measured, and the electric resistance value was calculated from the applied voltage value and the current value. As the voltage, a constant value of 1.0 V was applied using the same power source as in the confirmation experiment.

(1.2) Experimental Results When the electrical resistance value due to tension was measured, the electrical resistance value decreased from 0% to 20% in tensile elongation. On the other hand, the electrical resistance value increased when the tensile elongation changed from 20% to 30%. In the range where the tensile elongation changed from 30% to 70%, the electric resistance value decreased. Specifically, it was about 2.3Ω when the tensile elongation was 0%. When the tensile elongation was 20%, it was about 1.95Ω, and when the tensile elongation was 30%, it increased to about 2.0Ω. When the tensile elongation was 70%, it was about 1.9 Ω.

(2) Fluctuations in electrical resistance due to compression (2.1) Experimental method In experiments on fluctuations in electrical resistance due to compression, JIS (JAPAN Industrial Standards) was conducted in an environment with a temperature of 25 ± 2 ° C and a humidity of 50 ± 5% RH. ) The compressibility and compressive elastic modulus of L1096.8.20 were referred to. The test piece has a width of 100 mm and a length of 100 mm. First, the test piece was placed on a cushion made of 100% cotton, and the compression plate was placed so as to be located in the center of the test piece. The air pack was attached to the surface of the test piece, and the compression pressures of the air pack were 0 gf / cm ² , 50 gf / cm ² , 100 gf / cm ² , 150 gf / cm ² , and 200 gf / cm ² . The current value of the test piece at that time was measured, and the electric resistance value was calculated from the current value and the voltage value. As the voltage, a constant value of 1.0 V was applied using the same power source as in the confirmation experiment.

(2.2) Experimental results In both cases where a flat plate is used as the compression plate and a hemispherical plate is used, the electric resistance value when energized is slightly higher than 2.0Ω regardless of the compression pressure. It was measured and hardly changed.

(3) Fluctuation of electrical resistance value due to temperature change (3.1) Experimental method The experiment was carried out by placing a test piece inside an iron container that can be heated by a heater. The test piece used had a width of 100 mm and a length of 200 mm. The environment at the time of the experiment was a temperature of 25 ± 2 ° C. and a humidity of 50 ± 5% RH. In addition, electrodes were provided at both ends in the length direction. Using such an experimental device, the surface temperature of the test piece was raised by 10 ° C. from 30 ° C., and the current value at that time was measured. The temperature was raised at 2.5 ° C./min. Further, after reaching 80 ° C., the heating by the heater was stopped, the temperature of the test piece was naturally lowered, and the current value at the same temperature as when the temperature was raised was measured. The electric resistance value was calculated from the measured current value and voltage value. As the voltage, a constant value of 1.0 V was applied using the same power source as in the confirmation experiment.

(3.2) Experimental Results When the temperature of the test piece was 30 ° C., the electric resistance value was about 4Ω, and when the temperature was 80 ° C., the electric resistance value was about 3Ω. That is, while the temperature of the test piece increased from 30 ° C. to 80 ° C., the electric resistance value decreased by about 1Ω.

(4) Measurement of Thermal Shrinkage Rate of Conductive Thread (4.1) Experimental Method In this experiment, a conductive thread 10 having a length of 200 mm was used. The conductive yarn 10 was raised by 10 ° C. from 30 ° C. to 80 ° C. by a heat setter (PT-3 type) manufactured by Tsujii Dyeing Machinery Co., Ltd., and heated at each temperature for 5 minutes. After heating, the length of the conductive yarn 10 was measured, and the heat shrinkage rate was calculated by the following formula.

Heat shrinkage rate (%) = [(length after heating-length before heating) / length before heating] x 100

(4.2) Experimental Results As a result of the experiment, the conductive thread 10 contracted as the temperature increased. When the temperature was 80 ° C., it shrank by about 3% from the original length. This is because the nylon 66 used as the core wire shrinks due to heat. The electric resistance value decreased as the conductive thread 10 contracted. The electric resistance value is represented by "R = ρ × L / S". R is the electric resistance value (Ω), ρ is the electrical resistivity (Ω · m), L is the length (m) of the conductive thread 10, and S is the cross-sectional area (m ² ). From this equation, the electric resistance value decreases as the length of the conductive thread 10 shrinks.

From the results of the above confirmation experiment and the result of the comparative experiment, when a voltage was applied to the cloth 2 to raise the temperature of the cloth 2, the electric resistance decreased. In addition, the electric resistance value was greatly reduced as compared with the case where the cloth 2 was physically affected from the outside. Further, when a voltage was applied to the cloth 2 to raise the temperature of the cloth 2, the electric resistance value tended to decrease with a certain regularity. Specifically, when a voltage is applied to the fabric 2 to raise the temperature of the fabric 2, the electric resistance value decreases in the temperature range where the temperature of the fabric 2 is about 50 ° C. or lower as compared with the temperature range exceeding 50 ° C. There was a tendency that the degree of doing was large. There was a regularity that the degree of decrease gradually decreased when a voltage was applied to the fabric 2 to raise the temperature of the fabric 2. Therefore, it was found that the cloth 2 can be satisfactorily used as the surface sensor 1.

1 Plane sensor 1A Cloth heater 2 Cloth 3 Electrode 4 Wiring 5 Controller 10 Conductive thread 11 Core wire 12 Metal layer 15 Filament wire 20 Loop

Claims (5)

A plurality of loops are formed by conductive yarns, and the plurality of said conductive yarns are made of a fabric in which the loops are entwined with each other and woven, and an electric current flows through the conductive yarns to raise the temperature of the fabrics to raise the temperature of the adjacent fabrics. It is characterized in that the form of entanglement of threads is changed, the current path flowing through the fabric is shortened, or the contact between the loops is increased and the electric resistance value of the fabric is lowered. Plane sensor. The planar sensor according to claim 1, wherein the direction in which the current flows is the course direction in which the plurality of loops formed for each conductive thread are connected. The planar sensor according to claim 1 or 2, wherein the conductive thread is formed by twisting a plurality of filament wires having a metal conductor coated on the outer periphery of the core wire. A controller is connected to the fabric, and the controller lowers or increases the voltage applied to the fabric based on the detection means for detecting the electric resistance value of the fabric and the electric resistance value detected by the detecting means. The planar sensor according to any one of claims 1 to 3, further comprising a control means for stopping or starting the application of voltage. A cloth in which a plurality of loops are formed of conductive threads and the plurality of said conductive threads are entwined with each other and woven together, and an electrode portion composed of electrode threads and provided at intervals on the cloth. As the current flows through the conductive yarn and the temperature of the fabric rises, the form of entanglement of the adjacent conductive yarns changes, and the path of the current flowing through the fabric is shortened or A cloth heater characterized in that the contact between the loops is increased and the electric resistance value of the cloth is lowered.

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