Stiffness measurement sensor based on multi-level tactile receptor element, and driving method thereof

Abstract

A stiffness measurement sensor based on a multi-level tactile receptor element, according to an embodiment of the present invention, comprises: a substrate; a contact unit disposed under the substrate and partially spaced apart from the substrate; and an electrode unit disposed under the substrate and positioned to correspond to the contact unit. When external force is applied to an object to be measured, the object being positioned below the contact unit, the contact surface between the electrode unit and the contact unit may gradually increase.

Description

Stiffness measurement sensor based on multi-level tactile receptor elements, and driving method thereof

[0001] The following embodiments relate to a stiffness measurement sensor based on a multi-level tactile receptor element and a method for driving the same.

[0002] In the case of commercial products for measuring the stiffness of soft tissues such as skin, there is a disadvantage in that the product measures the force applied when the skin is pressed to a certain height, so the characteristics of the skin are measured in a static situation, resulting in a large error rate.

[0003] In addition, there is a technology for measuring stiffness in a dynamic situation based on the characteristic that the speed at which force is transmitted is proportional to the stiffness when force is applied at a constant speed, but this technology has the disadvantage of being difficult to miniaturize because the speed at which force is applied must be constant at a predetermined value.

[0004] Therefore, there is a need for a technology that can measure the stiffness of a material regardless of the speed of force application.

[0005] Publication No. 10-2022-0131595 discloses a device and method for measuring skin elasticity.

[0006] An object of one embodiment is to provide a stiffness measurement sensor based on a multi-level tactile receptor element capable of deriving the stiffness of a measurement object without being affected by the speed at which an external force is applied to the measurement object.

[0007] An object of one embodiment is to provide a multi-level tactile receptor element-based stiffness measurement sensor that is manufactured in a small size and has no durability issues of the element due to attachment / detachment, etc.

[0008] A multi-level tactile receptor element-based stiffness measurement sensor according to one embodiment includes a substrate, a contact portion disposed on a lower side of the substrate and partially spaced from the substrate, and an electrode portion disposed on a lower side of the substrate and positioned corresponding to the contact portion, wherein an area in which the electrode portion and the contact portion come into contact can gradually increase as an external force is applied to a measurement object located below the contact portion.

[0009] According to one embodiment, the contact portion includes a first elastic member and a second elastic member that can be pressed by an external force, the first elastic member having a thickness greater than that of the second elastic member, a lower end of the first elastic member being in contact with an upper surface of the measurement object, and a lower end of the second elastic member being spaced apart from the upper surface of the measurement object.

[0010] According to one embodiment, the first elastic member may include a first-first protruding element and a first-second protruding element positioned at the top, the first-first protruding element having a longer protruding length compared to the first-second protruding element, the second elastic member may include a second-first protruding element and a second-second protruding element positioned at the top, the second-first protruding element having a longer protruding length compared to the second-second protruding element, and the electrode portion may include first to fourth electrode members arranged at positions corresponding to the first-first, second-first, second-second, and first-second protruding elements, respectively.

[0011] According to one embodiment, when an external force is applied to the measurement object for a first time period, the measurement object contracts and the first elastic member contracts, so that the 1-1 protruding element begins to contract at the first time period, and the contact resistance of the 1-1 protruding element with the first electrode member rapidly decreases; when an external force is applied to the measurement object for a second time period, the measurement object contracts and the first elastic member and the second elastic member contract, so that the 2-1 protruding element begins to contract at the second time period, and the contact resistance of the 2-1 protruding element with the second electrode member rapidly decreases; when an external force is applied to the measurement object for a third time period, the measurement object contracts and the first elastic member and the second elastic member contract, so that the 2-2 protruding element begins to contract at the third time period, and the contact resistance of the 2-2 protruding element with the third electrode member rapidly decreases; the second time period may be defined as the time period from the first time period to the second time period, and the third time period may be defined as the time period from the second time period to the third time period.

[0012] In one embodiment, the second time may be inversely proportional to the speed at which the external force is applied to the contact portion, and the third time may be inversely proportional to the speed at which the external force is applied to the contact portion and the stiffness of the measurement object.

[0013] In one embodiment, the ratio of the second time to the third time may be proportional to the stiffness of the object being measured.

[0014] A multi-level tactile receptor element-based stiffness measurement sensor according to one embodiment further includes first to fourth switching elements connected to first to fourth electrode members, respectively, and each of the first to fourth switching elements performs a switch-on when a size of a contact resistance decreases below a certain level, thereby easily deriving a point in time when a size of a contact resistance with the first to fourth electrodes decreases below a certain level.

[0015] According to one embodiment, the first-1, first-2, second-1 and second-2 protruding elements are each composed of a plurality of them, and each of the first to fourth electrode members can form a closed circuit.

[0016] A method for driving a stiffness measurement sensor based on a multi-level tactile receptor element according to one embodiment may include a step of applying an external force to a measurement object for a first time period, so that a first-first protruding element begins to be compressed at a first time period, thereby rapidly reducing contact resistance with a first electrode member, a step of applying an external force to the measurement object for a second time period, so that a second-first protruding element begins to be compressed at a second time period, thereby rapidly reducing contact resistance with a second electrode member, a step of applying an external force to the measurement object for a third time period, so that a second-second protruding element begins to be compressed at a third time period, thereby rapidly reducing contact resistance with a third electrode member, and a step of deriving stiffness of the measurement object from a ratio of the second time period to the third time period.

[0017] A stiffness measurement sensor based on a multi-level tactile receptor element according to one embodiment can derive the stiffness of a measurement object without being affected by the speed at which an external force is applied to the measurement object.

[0018] A multi-level tactile receptor element-based stiffness measurement sensor according to one embodiment can be manufactured in a small size so that there is no durability issue of the element due to attachment / detachment, etc.

[0019] FIG. 1 illustrates the structure of a stiffness measurement sensor based on a multi-level tactile receptor element according to one embodiment.

[0020] FIG. 2 illustrates the first point in time when the first-1 protruding element begins to be compressed, according to one embodiment.

[0021] FIG. 3 illustrates the second point in time when the second-1 protruding element begins to be compressed, according to one embodiment.

[0022] FIG. 4 illustrates the third point in time when the second-second protrusion element begins to be compressed, according to one embodiment.

[0023] FIG. 5 is a graph showing voltage over time, according to one embodiment.

[0024] FIG. 6 schematically illustrates a circuit diagram connecting a first electrode member and a first switching element according to one embodiment.

[0025] FIG. 7 illustrates a cross-sectional view along line AA of FIG. 1, showing a circuit diagram in which the first to fourth electrodes are electrically connected, according to one embodiment.

[0026] FIG. 8 is a flowchart illustrating a method for driving a stiffness measurement sensor based on a multi-level tactile receptor element according to one embodiment.

[0027] Hereinafter, embodiments are described in detail with reference to the attached drawings. However, the embodiments may be modified in various ways, and the scope of the patent application is not limited or restricted by these embodiments. It should be understood that all modifications, equivalents, or alternatives to the embodiments are included within the scope of the patent application.

[0028] The terms used in the examples are for illustrative purposes only and should not be construed as limiting. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but should be understood to not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0029] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the embodiments pertain. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0030] In addition, when describing with reference to the attached drawings, identical components will be assigned the same reference numerals regardless of the drawing numbers, and redundant descriptions thereof will be omitted. When describing embodiments, if a detailed description of a related known technology is judged to unnecessarily obscure the gist of the embodiment, the detailed description will be omitted.

[0031] Additionally, terms such as first, second, A, B, (a), (b), etc. may be used to describe components of the embodiments. These terms are only intended to distinguish the components from other components, and the nature, order, or sequence of the components are not limited by the terms. When a component is described as being "connected," "coupled," or "connected" to another component, it should be understood that the component may be directly connected or connected to the other component, but another component may also be "connected," "coupled," or "connected" between each component.

[0032] Components included in one embodiment and components with common functions will be described using the same names in other embodiments. Unless otherwise stated, the descriptions given in one embodiment may also apply to other embodiments, and detailed descriptions will be omitted to the extent of overlap.

[0033] FIG. 1 illustrates the structure of a multi-level tactile receptor element-based stiffness measurement sensor (1) according to one embodiment.

[0034] Referring to FIG. 1, a multi-level tactile receptor element-based stiffness measurement sensor (1, hereinafter referred to as a “stiffness measurement sensor”) according to one embodiment may include a substrate (10), a contact portion (100) disposed on the lower side of the substrate (10) and partially spaced from the substrate (10), and an electrode portion (30) disposed on the lower side of the substrate (10) and disposed to correspond to the contact portion (100), and as an external force is applied to a measurement object (20) located below the contact portion (100), an area of ​​contact between the electrode portion (30) and the contact portion (100) may gradually increase.

[0035] The substrate (10) is connected to the electrode portion (30) and can form an overall circuit including the electrode portion (30). The substrate (10) can be made of a PCB (PRINTED CIRCUIT BOARD) integrated circuit, silicon dioxide (SiO2), silicon (Si), or the like.

[0036] The measurement object (20) may correspond to soft tissue such as skin.

[0037] The contact portion (100) includes a first elastic member (110) and a second elastic member (120) that can be pressed by an external force, and the first elastic member (110) has a thicker thickness than the second elastic member (120), and the lower end of the first elastic member (110) is in contact with the upper surface of the measurement object (20), and the lower end of the second elastic member (120) can be spaced apart from the upper surface of the measurement object (20). The first elastic member (110) and the second elastic member (120) can be composed of a silicone elastic body such as PDMS (organic silicon compound, polydimethylsiloxane).

[0038] The first elastic member (110) may include a first-first protruding element (111) and a first-second protruding element (112) located at the top, and the first-first protruding element (111) may have a longer protruding length compared to the first-second protruding element (112). The first-first protruding element (111) and the first-second protruding element (112) may be coated with a conductive material. Meanwhile, the first-first protruding element (111) and the first-second protruding element (112) may not be coated with a conductive material for insulation.

[0039] The second elastic member (120) may include a second-first protruding element (121) and a second-second protruding element (122) located at the upper end, and the second-first protruding element (121) may have a longer protruding length compared to the second-second protruding element (122). The second-first protruding element (121) and the second-second protruding element (122) may be coated with a conductive material. Meanwhile, the second-first protruding element (121) and the second-second protruding element (122) may not be coated with a conductive material for insulation.

[0040] The first-1, first-2, second-1, and second-2 protruding elements (111, 112, 121, 122) have a conductive material coated on the upper portion as described above so that the conductive material can come into contact with the electrode portion (30). The first-1, first-2, second-1, and second-2 protruding elements (111, 112, 121, 122) are illustrated in the shape of a triangular pyramid in FIG. 1, but this is only one example, and they may have various shapes such as a hemispherical shape. In this case, the conductive material may be composed of a SWNT (Single-Walled Carbon NanoTube).

[0041] Meanwhile, the first-first protruding element (111) and the second-first protruding element (121) may have the same length, and it may be preferable for the second-second protruding element (122) to be longer than the first-second protruding element (112).

[0042] The electrode part (30) may include first to fourth electrode members (31, 32, 33, 34) arranged at positions corresponding to the first-1, second-1, second-2, and first-2 protruding elements (111, 121, 122, 112), respectively. As an external force is applied to the contact portion (100), each of the first-first, second-first, second-second and first-second protruding elements (111, 121, 122, 112) is compressed, so that the contact area between the first to fourth electrode members (31, 32, 33, 34) and the first-first, second-first, second-second and first-second protruding elements (111, 121, 122, 112) can gradually increase, and thus the contact resistance with the first to fourth electrode members (31, 32, 33, 34) can decrease. Meanwhile, the electrode portion (30) can be made of gold (Au), etc.

[0043] FIG. 2 shows, according to one embodiment, a first point in time (111) at which the first protruding element (111) begins to compress. ) is shown. Fig. 3 shows the second point in time ( ) when the second-1 protruding element (121) starts to be compressed, according to one embodiment. ) is shown. Fig. 4 shows the third point in time ( ) when the second-second protrusion element (122) starts to be compressed, according to one embodiment. ) shows the appearance.

[0044] Figures 2 to 4 correspond to examples of driving a stiffness measurement sensor (1) according to one embodiment.

[0045] Referring to Fig. 2, when an external force is applied to the measurement object (20) for a first time, the measurement object (20) contracts and the first elastic member (110) contracts, so that at the first time point ( ) the first-first protrusion element (111) begins to contract, and the contact resistance of the first-first protrusion element (111) with the first electrode member (31) may be rapidly reduced.

[0046] Referring to Figure 3, an external force is applied to the measurement object (20) at a second time ( ) is applied during the measurement, the measurement object (20) contracts and the first elastic member (110) and the second elastic member (120) contract, so that at the second time point ( ) the second-first protruding element (121) begins to contract, so that the contact resistance of the second-first protruding element (121) with the second electrode member (32) can be rapidly reduced. At this time, as the first elastic member (110) is pressed, the first-first protruding element (111) is also pressed, and thus, the contact area between the first-first protruding element (111) and the first electrode member (31) can increase.

[0047] Referring to Fig. 4, an external force is applied to the measurement object (20) at the third time ( ) is applied during the measurement, the measurement object (20) contracts and the first elastic member (110) and the second elastic member (120) contract, so that at the third time point ( ) the 2nd protruding element (122) begins to contract, so that the contact resistance of the 2nd protruding element (122) with the 3rd electrode member (33) can be rapidly reduced. At this time, as the 1st elastic member (110) and the 2nd elastic member (120) are pressed, the 1st protruding element (111) and the 2nd protruding element (121) are also pressed, and therefore, the contact area between the 1st protruding element (111) and the 1st electrode member (31) can be further increased, and the contact area between the 2nd protruding element (121) and the 2nd electrode member (32) can be increased.

[0048] Meanwhile, here is the second time( ) is the first point in time ( ) from the second point of view ( ) is defined as the time until the third hour ( ) is the second point of view ( ) from the third point of view ( ) can be defined as the time until.

[0049] FIG. 5 is a graph showing voltage (V) versus time (t), according to one embodiment.

[0050] The voltage (V) shown in Fig. 5 may be inversely proportional to the contact resistance. That is, for example, the voltage (V) may correspond to the voltage applied between the load resistors when a constant voltage is applied to the circuit from the outside in a circuit in which the stiffness measurement sensor (1) and the load resistor are connected in series.

[0051] Referring to Figure 5, the second time ( ) is the first point in time when the contact resistance between the first electrode member (31) and the first protruding element (111) is rapidly reduced. ) from the second point of contact where the contact resistance between the second electrode member (32) and the second-1 protruding element (121) is rapidly reduced. ) may correspond to the time until the 3rd hour ( ) is the second point of view ( ) from the third point in time when the contact resistance between the 2nd-2 protrusion element (122) and the 3rd electrode member (33) is rapidly reduced. ) can be defined as the time until.

[0052] Meanwhile, according to one embodiment, the second time ( ) is the speed at which an external force is applied to the contact portion (100). ) is inversely proportional to the third time ( ) is the speed at which an external force is applied to the contact portion (100). ) and the stiffness of the measurement object (20) ) can be inversely proportional.

[0053] Therefore, the third hour ( ) for the second time( ) is the ratio of the stiffness of the measurement object (20) ) can be proportional to.

[0054] Specifically, as above, the third hour ( ) for the second time( ) from the ratio of the stiffness of the measurement object (20) ) can be derived according to the following mathematical equations 1 to 4.

[0055] Second hour ( ) can be expressed according to the following mathematical formula 1.

[0056] [Mathematical Formula 1]

[0057]

[0058] In mathematical equation 1, is the second hour, is the speed at which an external force is applied to the measurement object (20) and may mean the difference in thickness between the first elastic member (110) and the second elastic member (120).

[0059] Assuming that the measurement object (20) and the contact portion (100) are linearly elastic, the third time ( ) can be expressed according to the following mathematical formula 2.

[0060] [Equation 2]

[0061]

[0062] In mathematical expression 2, is the third hour, is the stiffness of the measurement object (20), is the speed at which an external force is applied to the measurement object (20) and may mean the size of the external force required to press the 2-1 protruding element (121) by the amount of the difference in length between the 2-1 protruding element (121) and the 2-2 protruding element (122).

[0063] The above mathematical expression 2 is the magnitude of the external force applied to the measurement object (20). ) can be derived from the fact that the size of the external force required to press the 2-1 protruding element (121) by the length difference between the 2-1 protruding element (121) and the 2-2 protruding element (122) is the same.

[0064] At this time, the size of the external force applied to the measurement object (20) ) can be expressed according to the following mathematical formula 3.

[0065] [Equation 3]

[0066]

[0067] In mathematical expression 3, is the size of the external force applied to the measurement object (20), is the speed at which an external force is applied to the measurement object (20) and may correspond to the third hour.

[0068] Therefore, from the above mathematical expressions 1 and 2, the stiffness of the measurement object (20) is obtained according to the following mathematical expression 4. ) is the third hour ( ) for the second time( ) can be derived to be proportional to the ratio.

[0069] [Equation 4]

[0070]

[0071] In mathematical equation 4, is the stiffness of the measurement object (20), is the second hour, is the third hour, is the size of the external force required to press the difference in length between the 2-1 protruding element (121) and the 2-2 protruding element (122), and may mean the difference in thickness between the first elastic member (110) and the second elastic member (120).

[0072] That is, the stiffness of the measurement object (20) ) is the third hour ( ) for the second time( ) is proportional to the ratio of , and at this time, in the mathematical expression 5 described later, the general constant ( ) the magnitude of the external force introduced ( ) into mathematical expression 4, the stiffness of the measurement object (20) is ) can be derived. That is, by introducing a certain constant, the stiffness ( ) can be derived.

[0073] Meanwhile, as can be seen in mathematical expression 4, the third time ( ) for the second time( ) from the ratio of the speed at which the external force is applied to the measurement object (20) ) is removed, the stiffness measurement sensor (1) is applied with an external force to the measurement object (20) at a speed ( ) can measure the stiffness of the measurement object (20) without being affected by the object.

[0074] For reference, the size of the external force required to press the 2-1 protruding element (121) by the length difference between the 2-1 protruding element (121) and the 2-2 protruding element (122) ) can be expressed as in the following mathematical formula 5.

[0075] [Equation 5]

[0076]

[0077] In mathematical equation 5, is the size of the external force required to press the 2-1 protruding element (121) by the length difference between the 2-1 protruding element (121) and the 2-2 protruding element (122). is a general constant, is the elastic coefficient of the 2-1 protruding element (121), is the length of the 2nd-1 protruding element (121), is the length of the base of the 2nd-1 protruding element (121), is the inclination angle of the 2-1 protruding element (121) and may mean the difference in length between the 2-1 protruding element (121) and the 2-2 protruding element (122).

[0078] Meanwhile, when the stiffness of the measurement object (20) is uneven, the point at which the first-second protrusion element (112) begins to compress ( ) and the point at which the first-first protrusion element (111) begins to compress ( ) can additionally derive the stiffness of the measurement object (20) in contact with the first elastic member (110).

[0079] Meanwhile, the above mathematical expressions 1 to 5 assume that the measurement object (20) and the contact portion (100) are linearly elastic, but this is only an example, and even when the measurement object (20) and the contact portion (100) correspond to hyper-elastic or viscous-elastic, the stiffness of the measurement object (20) is the same as or similar to the above process. ) can be derived. Meanwhile, in the case where the measurement object (20) and the contact portion (100) correspond to hyper-elastic or viscous-elastic, the stiffness of the measurement object (20) ) is the third hour ( ) for the second time( ) may be non-linearly proportional rather than linearly proportional to the ratio.

[0080] FIG. 6 schematically illustrates a circuit diagram connecting a first electrode member (31) and a first switching element (40) according to one embodiment.

[0081] Referring to FIG. 6, a stiffness measurement sensor (1) according to one embodiment may further include a first switching element (40) connected to a first electrode member (31). Similarly, it may further include second to fourth switching elements (not shown) connected to second to fourth electrode members (32, 33, 34).

[0082] The first to fourth switching elements (40) can perform a switch-on when the magnitude of the resistance of each of the first to fourth electrode members (31, 32, 33, 34) decreases and reaches a threshold voltage or higher. Meanwhile, the switch-off can also be performed when the magnitude of the resistance of each of the first to fourth electrode members (31, 32, 33, 34) increases above a certain level.

[0083] When the upper part of the contact portion (100) (i.e., the part including the first-first, first-second, second-first and second-second protruding elements (111, 112, 121, 122)) and the electrode portion (30) are collectively referred to as a piezoresistive element, it may be difficult to easily derive the point in time when the resistance of the signal (resistance, voltage or current) of the piezoresistive element is rapidly reduced because the resistance changes continuously.

[0084] In order to solve the above problem, the first to fourth switching elements (40) are switched on when the resistance of the piezoresistive element is lowered below a certain level, so that the point in time when the first, second, second, and second protruding elements (111, 112, 121, 122) are compressed or the point in time when the resistance of the piezoresistive element is lowered below a certain level can be easily derived. In other words, a kind of signal-to-noise ratio increases, so that the point in time when the resistance is lowered below a certain level can be easily derived.

[0085] Meanwhile, although the first to fourth switching elements (40) are described in this specification as simply switching on or off at a specific resistance value or a specific applied voltage, this is only one embodiment, and it is obvious that they can be elements that generate a spike signal when switching on as an OTS switching element if necessary, and that the spike signal disappears when switching off. Meanwhile, when an OTS switching element is used, the point in time when the resistance size is lowered below a certain level can be easily derived based on the point in time when the spike is generated. When the frequency of the spike is 1 MHz, the spike interval is 1 us, so the error in the derived start point can be very low, such as at the level of 1 us.

[0086] FIG. 7 illustrates a cross-sectional view along line AA of FIG. 1, showing a circuit diagram in which the first to fourth electrode members (31, 32, 33, 34) are electrically connected, according to one embodiment.

[0087] According to one embodiment, the first-first, first-second, second-first and second-second protruding elements (111, 112, 121, 122) are each composed of a plurality of pieces, and the first to fourth electrode members (31, 32, 33, 34) can each form a closed circuit.

[0088] At this time, the reactivity and sensitivity of each of the first to fourth electrode members (31, 32, 33, 34) can be controlled according to the number of each of the first-1, first-2, second-1, and second-2 protruding elements (111, 112, 121, 122) and the conductivity value of the conductive material coated on the bottom of each.

[0089] Fig. 8 is a flowchart illustrating a method of driving a stiffness measurement sensor (1) according to one embodiment.

[0090] Referring to FIGS. 2 to 4 and FIG. 8, a driving method of a stiffness measurement sensor (1) according to one embodiment is as follows.

[0091] First, an external force is applied to the measurement object (20) for a first time, and at the first time point ( ) the first-first protrusion element (111) begins to be compressed, and the contact resistance with the first electrode member (31) can be rapidly reduced (S101).

[0092] Next, the second time ( ) an external force is applied, and at the second point in time ( ) the second-1 protrusion element (121) begins to be compressed, and the contact resistance with the second electrode member (32) can be rapidly reduced (S102).

[0093] Next, the third time ( ) during which an external force is applied, at the third point in time ( ) the second-second protrusion element (122) begins to be compressed, and the contact resistance with the third electrode member (33) can be rapidly reduced (S103).

[0094] From steps S102 and S103, the third time ( ) for the second time( ) can be obtained, and the stiffness of the measurement object (20) can be derived from it according to the above mathematical formulas 1 to 4 (S104).

[0095] As discussed above, the stiffness measurement sensor (1) according to one embodiment measures the speed at which an external force is applied to the measurement object (20). ) can be used to derive the stiffness of the measurement object (20) without being affected by the influence of the measurement object (20).

[0096] In addition, the stiffness measurement sensor (1) according to one embodiment is manufactured in a small size so that there may be no durability issues of the element due to attachment / detachment, etc.

[0097] Although the embodiments described above have been described with limited drawings, those skilled in the art will appreciate that various technical modifications and variations can be applied based on the above. For example, appropriate results can still be achieved even if the described techniques are performed in a different order than described, and / or components of the described systems, structures, devices, circuits, etc. are combined or combined in a different manner than described, or are replaced or substituted with other components or equivalents.

[0098] Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the claims described below.

Claims

1. Substrate; a contact portion disposed on the lower side of the substrate and partially spaced from the substrate; and An electrode portion arranged at the bottom of the substrate and arranged to correspond to the contact portion; Including, As an external force is applied to the measurement target located below the contact portion, the area of contact between the electrode portion and the contact portion gradually increases. Stiffness measurement sensor based on multi-level tactile receptor elements.

2. In paragraph 1, The above contact part, It comprises a first elastic member and a second elastic member that can be pressurized by an external force, The first elastic member is thicker than the second elastic member, The lower end of the first elastic member is in contact with the upper surface of the measurement object, The lower end of the second elastic member is spaced apart from the upper surface of the measurement object. Stiffness measurement sensor based on multi-level tactile receptor elements.

3. In paragraph 2, The above first elastic member includes a first-first protruding element located at the top, The second elastic member includes a second-first protruding element and a second-second protruding element located at the top, and the second-first protruding element has a longer protruding length compared to the second-second protruding element. The above electrode part includes first to third electrode members arranged at positions corresponding to the first-1, second-1 and second-2 protruding elements, respectively. Stiffness measurement sensor based on multi-level tactile receptor elements.

4. In paragraph 3, When an external force is applied to the above measurement object for a first time, the measurement object contracts and the first elastic member contracts, so that the first-first protruding element begins to contract at the first time point, and the contact resistance of the first-first protruding element with the first electrode member rapidly decreases. When an external force is applied to the above measurement object for a second time, the measurement object contracts and the first elastic member and the second elastic member contract, so that the 2-1 protruding element begins to contract at the second time point, and the contact resistance of the 2-1 protruding element with the second electrode member rapidly decreases. When an external force is applied to the above measurement object for a third time, the measurement object contracts and the first elastic member and the second elastic member contract, so that the 2-2 protruding element begins to contract at the third time point, and the contact resistance of the 2-1 protruding element with the third electrode member rapidly decreases. The second time is defined as the time from the first time point to the second time point, and the third time is defined as the time from the second time point to the third time point. Stiffness measurement sensor based on multi-level tactile receptor elements.

5. In paragraph 4, The above second time is inversely proportional to the speed at which an external force is applied to the contact portion, The third time is inversely proportional to the speed at which the external force is applied to the contact portion and the stiffness of the measurement object. Stiffness measurement sensor based on multi-level tactile receptor elements.

6. In paragraph 5, A stiffness measurement sensor based on multi-level tactile receptor elements, wherein the ratio of the second time to the third time is proportional to the stiffness of the measurement object.

7. In paragraph 3, First to third switching elements each connected to the first to third electrode members; Including more, Each of the first to third switching elements performs a switch-on when the size of the contact resistance falls below a certain level. Stiffness measurement sensor based on multi-level tactile receptor elements.

8. In paragraph 3, The above 1-1, 2-1 and 2-2 protruding elements are each composed of a plurality of pieces, Each of the first to third electrode members constitutes a closed circuit. Stiffness measurement sensor based on multi-level tactile receptor elements.

9. A step in which an external force is applied to the measurement target for a first time period, the first-first protruding element begins to be compressed at the first time point, and the contact resistance with the first electrode member is rapidly reduced; A step in which an external force is applied to the above measurement object for a second time, the second-1 protruding element begins to be compressed at a second time point, and the contact resistance with the second electrode member rapidly decreases; A step in which an external force is applied to the above measurement object for a third time, and at a third time point, the second-second protruding element begins to be compressed, and the contact resistance with the third electrode member is rapidly reduced; and A step of deriving the stiffness of the measurement object from the ratio of the second time to the third time; A method for driving a stiffness measurement sensor based on a multi-level tactile receptor element, comprising:

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