Method and detection member for estimating the gaze of a subject

Abstract

This invention provides a method for accurately estimating the gaze of a subject. [Solution] According to one aspect of the present invention, a method for estimating the gaze of a subject is provided, comprising an acquisition step and an estimation step, wherein in the acquisition step, a resistance value related to a detection member is acquired from a detection member attached to the eyelid or surrounding skin of the subject, where the detection member is a member with a thickness of 100 μm or less having a conductive layer in at least a part of its structure, and the resistance value is the resistance value of the conductive layer which fluctuates as the detection member expands and contracts in response to the movement of the skin, and in the estimation step, the gaze of the subject is estimated based on the acquired resistance value and preset reference information, where the reference information is information that associates the resistance value with the gaze of the subject.

Description

[Technical Field]

[0001] The present invention relates to a method for estimating the line of sight of a subject and a detection member. [Background Art]

[0002] Conventionally, techniques for estimating which direction a human or the like is looking have been developed. Such a technique, also called eye tracking, is expected to be utilized in various fields such as medical care, games, and sports. As a technique for estimating the line of sight of such a subject, for example, Patent Document 1 discloses an apparatus including an eye tracking camera worn on the head. Further, Patent Document 2 discloses a method for estimating the line of sight direction by having a subject wear a predetermined contact lens. Furthermore, in recent years, as Non-Patent Document 1, a technique for performing eye tracking using a strain sensor to control an avatar has been disclosed. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese National Publication of International Patent Application No. 2014-515291 [Patent Document 2] Japanese Unexamined Patent Publication No. 2013-158470 [Non-Patent Documents]

[0004] [Non-Patent Document 1] Adv. Mater. Technol. 2024, 9, 2302211 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] However, the technology disclosed in Patent Document 1 may require frequent calibration because the device to be worn is susceptible to the effects of ambient light and other factors. Furthermore, the technology disclosed in Patent Document 2 requires the wearer to wear contact lenses, leaving room for improvement in terms of usability. Moreover, even in the technology disclosed in Non-Patent Document 1, there is still room for improvement in the accuracy of gaze estimation.

[0006] In view of the above circumstances, the present invention aims to provide a method, etc., that can appropriately estimate the gaze of a target person. [Means for solving the problem]

[0007] According to one aspect of the present invention, a method for estimating a subject's gaze is provided, comprising an acquisition step and an estimation step, wherein in the acquisition step, a resistance value related to a detection member is acquired from a detection member attached to the subject's eyelid or the skin around the eyelid, where the detection member is a member with a thickness of 100 μm or less having a conductive layer in at least a part of its structure, and the resistance value is the resistance value of the conductive layer which changes as the detection member expands and contracts in response to the movement of the skin, and in the estimation step, the subject's gaze is estimated based on the acquired resistance value and preset reference information, where the reference information is information that associates the resistance value with the subject's gaze.

[0008] According to the above embodiment, a method is provided that can appropriately estimate the gaze of a subject. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram illustrating the various configurations related to the estimation method of this embodiment. [Figure 2] This is a block diagram showing the hardware configuration of terminal device 3. [Figure 3] This is a block diagram showing the functions implemented by the control unit 31 of the terminal device 3. [Figure 4] This is a flowchart illustrating the details of the estimation method in this embodiment. [Figure 5] This is a conceptual diagram showing how the detection member 1 is attached to the subject's SBJ. [Figure 6] This is a conceptual diagram showing how the detection member 1 is attached to the subject's SBJ. [Figure 7] This is a cross-sectional view illustrating the adhesive laminate 4 in this embodiment. [Figure 8] This is a conceptual diagram showing an example of the application method according to this embodiment. [Figure 9] This is a conceptual diagram showing an example of the application method according to this embodiment. [Figure 10] This is a schematic diagram illustrating the shape of the conductive layer 11 in this embodiment. [Figure 11] This is a schematic diagram illustrating the shape of the conductive layer 11 in this embodiment. [Figure 12] This is a photograph showing the detection member attached in the example. [Figure 13] This graph shows the resistance values ​​detected by the detection member in the embodiment. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described below. The various features shown in the embodiments below can be combined with each other. Furthermore, unless otherwise specified, "~" in this specification represents the following from the above.

[0011] In other words, the method for estimating the gaze of the subject in this embodiment (hereinafter sometimes simply referred to as the "estimation method") is as follows. A method for estimating the gaze of a subject, It comprises an acquisition process and an estimation process, In the acquisition step, the resistance value of the detection member is obtained from the detection member attached to the eyelid or surrounding skin of the subject, Here, the detection member is a member having a conductive layer in at least a part of its structure and a thickness of 100 μm or less. The resistance value is a resistance value of the conductive layer that varies as the detection member expands and contracts in response to movement of the skin, in the estimation step, the line of sight of the subject is estimated based on the acquired resistance value and preset reference information, wherein the reference information is information in which a resistance value and the line of sight of the subject are associated with each other.

[0012] Incidentally, a program for implementing software according to an embodiment may be provided as a non-transitory computer-readable medium, may be provided to be downloadable from an external server, or may be provided such that the program is executed by an external computer to implement its functions in a client terminal (so-called cloud computing).

[0013] Furthermore, in various types of information processing according to an embodiment, input and output corresponding to the input can be realized. Here, as long as an output can be obtained as a result of the input, the form of information referred to in such information processing (hereinafter referred to as reference information) is not limited. The reference information may be, for example, rule-based information such as a database, a lookup table, a predetermined function (including judgment formulas such as regression formulas constructed by statistical methods), a trained model obtained by pre-learning the correlation between inputs and outputs, or a generative AI such as a large language model or a visual language model that can output desired results by inputting a prompt.

[0014] Furthermore, in one embodiment, "part" may include, for example, hardware resources implemented by a circuit in a broad sense, and the information processing of software that can be specifically realized by these hardware resources. Also, in one embodiment, various types of information are handled, and this information can be represented, for example, by the physical values ​​of signal values ​​representing voltage and current, the high or low values ​​of signal values ​​as a set of binary bits composed of 0s or 1s, or by quantum superposition (so-called qubits), and communication and calculations can be performed on a circuit in a broad sense.

[0015] Furthermore, a circuit in a broad sense is a circuit realized by combining at least a suitable combination of circuits, circuits, processors, and memory. The processor may be a general-purpose processor or a dedicated circuit. In other words, it includes application-specific integrated circuits (ASICs), programmable logic devices (for example, simple programmable logic devices (SPLDs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs)), etc.

[0016] 1. Overall Structure First, the various configurations related to the estimation method of this embodiment will be described. Figure 1 is a schematic diagram illustrating the various configurations related to the estimation method of this embodiment. The estimation method of this embodiment estimates the gaze of the subject SBJ by combining an acquisition step and an estimation step. The estimation method of this embodiment is characterized by performing the estimation using a predetermined detection member 1. Furthermore, "estimating the gaze" typically means estimating the positional relationship of the iris and / or pupil (black of the eye) of the subject SBJ. Note that the estimation of the gaze here may be an estimation of the relative position of the iris and / or pupil (black of the eye) of the subject SBJ along the horizontal and / or vertical axes. In other words, an embodiment in which the position of the iris and / or pupil (black of the eye) of the subject SBJ is estimated along one of the horizontal and vertical directions (axis) is also included as an example of the estimation method of this embodiment. On the other hand, the estimation method of this embodiment can also estimate the position of the iris and / or pupil (black of the eye) of the subject's SBJ along two or more axes (typically both horizontal and vertical axes). In this case, the position of the iris and / or pupil (black of the eye) of the subject's SBJ may typically be estimated along coordinates based on two or more axes (typically horizontal and vertical). In this specification, "horizontal direction" and "vertical direction" refer to the horizontal and vertical directions when a human (subject's SBJ) is standing upright.

[0017] In performing this estimation method, the detection member 1 is attached near the eye EY. Specifically, the detection member 1 is attached to the eyelid or the skin surrounding the eyelid of the subject's SBJ. Here, "attached around the eyelid" can be defined as the detection member 1 being attached to the subject's SBJ such that, for example, the distance between the proximal end of the detection member 1 relative to the eye EY and the eyelid is 20 mm or less (or 15 mm or less, or 10 mm or less). Attaching the detection member 1 to the tear trough or eye bag is also an example of "attaching around the eyelid". Furthermore, in this embodiment, "eyelid" may include both the upper eyelid and the lower eyelid. That is, the detection member 1 may be positioned above the eye EY, below it, or both above and below it. In this specification, "upwards" and "downwards" refer to the upward and downward directions when a human being (subject SBJ) is standing upright.

[0018] Furthermore, the number of detection members 1 attached to the subject's SBJ can be set as appropriate, and it is possible to attach one detection member 1 to the subject's SBJ or to attach multiple detection members 1 to the subject's SBJ. That is, in the estimation method of this embodiment, in the acquisition step, resistance values ​​related to the detection members can be obtained from each of two or more detection members 1. Then, in the estimation step, the gaze direction of the subject's SBJ can be estimated based on the two or more resistance values ​​obtained. Figure 1 shows a configuration in which two detection members 1 (detection member 1A and detection member 1B) are attached to the subject's SBJ. Note that the configuration in which multiple detection members 1 are attached includes both configurations in which multiple detection members 1 are attached near one eye and configurations in which a total of two or more detection members 1 are attached near either of the eyes.

[0019] In the estimation method of this embodiment, a resistance value related to the detection member 1 is obtained, and the gaze direction of the subject SBJ is estimated based on this resistance value. Here, the resistance value used for estimating the gaze direction is the resistance value of the conductive layer, which fluctuates as the detection member 1 expands and contracts in response to the movement of the skin SK. In other words, the detection member 1 has a conductive layer inside, and this conductive layer may be distorted as the skin SK expands and contracts, and the resistance value may fluctuate based on this distortion. To put it another way, the detection member 1 is a member whose detection parameters change in accordance with the distortion of this conductive layer. From this viewpoint, the detection member 1 may be called a strain sensor.

[0020] When estimating the line of sight, the method for obtaining resistance values ​​can be arbitrarily set, but one example is to use a resistance value acquisition device 2 electrically connected to the detection member 1 and a terminal device 3. This resistance value acquisition device 2 can supply power to the detection member 1 via wiring W. Furthermore, the resistance value acquisition device 2 may be configured to acquire the resistance value of the conductive layer provided on the detection member 1 when power is supplied to the detection member 1. Specifically, the resistance value acquisition device 2 can supply electricity to the conductive layer of the detection member 1, and in this state of supplying electricity, it may be able to acquire current values ​​and voltage values. Based on the relationship between the acquired current value and voltage value, the resistance value of the conductive layer of the detection member 1 can be determined. Although only one resistance value acquisition device 2 is shown in Figure 1, two or more resistance value acquisition devices 2 may be used to acquire resistance values. For example, as shown in Figure 1, when acquiring resistance values ​​from multiple detection members 1, one resistance value acquisition device 2 may be used to acquire resistance values ​​from each of the multiple detection members 1. Alternatively, a resistance value acquisition device 2 may be prepared according to the number of detection members 1, and the resistance value may be acquired based on each of the resistance value acquisition devices 2. Furthermore, the resistance value acquisition device 2 may be a device that can be worn by the subject SBJ.

[0021] Furthermore, terminal device 3 may be configured to communicate with resistance value acquisition device 2 via a communication line. The connection between the devices here may be wired or wireless. The hardware configuration of terminal device 3 will be described below.

[0022] Figure 2 is a block diagram showing the hardware configuration of terminal device 3. As shown in Figure 2, terminal device 3 comprises a control unit 31, a storage unit 32, a communication unit 33, an input unit 34, an output unit 35, and a communication bus 36. The control unit 31, storage unit 32, communication unit 33, input unit 34, and output unit 35 are electrically connected within terminal device 3 via the communication bus 36.

[0023] <Control Unit 31> The control unit 31 performs processing and control of the overall operation related to the terminal device 3. The control unit 31 is, for example, a Central Processing Unit (CPU). The control unit 31 realizes various functions related to the terminal device 3 by reading predetermined programs stored in the memory unit 32. That is, information processing by software stored in the memory unit 32 is concretely realized by the control unit 31, which is an example of hardware, and can be executed as each functional unit included in the control unit 31. These will be described in more detail in the next section. Note that the control unit 31 is not limited to being a single unit, and the terminal device 3 may have multiple control units 31 for each function. Furthermore, the terminal device 3 may be composed of a combination of these.

[0024] <Storage section 32> The storage unit 32 stores various types of information as defined above. This can be implemented, for example, as a storage device such as a solid-state drive (SSD) that stores various programs related to the terminal device 3 executed by the control unit 31, or as memory such as random access memory (RAM) that stores temporarily necessary information (arguments, arrays, etc.) related to program calculations. The storage unit 32 stores various programs, variables, etc. related to the terminal device 3 executed by the control unit 31.

[0025] <Communications Department 33> The communication unit 33 preferably uses wired communication methods such as USB, IEEE1394, Thunderbolt®, and wired LAN network communication, but may also include wireless LAN network communication, mobile communication such as LTE / 5G, and Bluetooth® communication as needed. In other words, it is more preferable to implement it as a collection of these multiple communication methods. That is, the terminal device 3 may communicate various information from the outside via the communication unit 33 and the network.

[0026] <Input section 34> The input unit 34 receives operation input from the user. The operation input is transmitted to the control unit 31 via the communication bus 36 as a command signal. The control unit 31 can perform predetermined controls or calculations based on the transmitted command signal as needed. The input unit 34 may be included in the housing of the terminal device 3 or it may be external. For example, the input unit 34 may be implemented as a touch panel integrated with the output unit 35. When the input unit 34 is implemented as a touch panel, the user can input tap operations, swipe operations, etc. to the input unit 34. Instead of a touch panel, the input unit 34 can be a switch button, mouse, trackpad, QWERTY keyboard, etc.

[0027] <Output section 35> The output unit 35 displays a graphical user interface (GUI) screen that can be operated by the user. The output unit 35 may be included in the housing of the terminal device 3 or it may be an external device. Specifically, the output unit 35 can be implemented as a display device such as a CRT display, liquid crystal display, organic EL display, or plasma display. It is preferable that these display devices be used in accordance with the type of terminal device 3.

[0028] Although Figure 1 shows an example where terminal device 3 is a laptop PC (Personal Computer), the type of terminal device 3 is not particularly limited in this embodiment. That is, terminal device 3 may be various information processing terminals such as desktop PCs, laptop PCs, smartphones, and tablet terminals.

[0029] 2. Functional configuration of terminal device 3 This section describes the functional configuration of the terminal device 3 in this embodiment. Information processing by software stored in the memory unit 32 is specifically realized by the control unit 31, which is an example of hardware, and can be executed as each functional unit included in the control unit 31 (the processor provided by the terminal device 3).

[0030] Figure 3 is a block diagram showing the functions realized by the control unit 31 of the terminal device 3. As shown in Figure 3, the control unit 31 of the terminal device 3 includes an acquisition unit 311, an estimation unit 312, a display control unit 313, and a storage management unit 314.

[0031] <Acquisition part 311> The acquisition unit 311 is configured to perform the acquisition process. In the acquisition process, the acquisition unit 311 acquires various information. In this embodiment, the acquisition unit 311 acquires a resistance value related to the detection member 1 attached to the eyelid or surrounding skin of the subject SBJ. Details of this process will be explained later.

[0032] <Estimation section 312> The estimation unit 312 is configured to perform the estimation process. In the estimation process, the estimation unit 312 estimates various events, etc., based on the acquired information. In the example of this embodiment, the estimation unit 312 estimates the gaze of the subject SBJ based on the acquired resistance value and pre-set reference information. The reference information here is information that associates the resistance value with the gaze of the subject SBJ. Details of this process will be explained later.

[0033] <Display Control Unit 313> The display control unit 313 is configured to execute the display control process. In the display control process, the display control unit 313 generates various display information and controls the display content that can be viewed by the user. The display information may be the information itself that is generated in a manner that can be viewed by the user, such as a screen, image, icon, or text, or it may be rendering information for displaying a screen, image, icon, text, etc. on various terminals.

[0034] <Storage management section 314> The memory management unit 314 is configured to perform the memory management process. In the memory management process, the memory management unit 314 manages various information to be stored, related to the estimation method of this embodiment. Typically, the memory management unit 314 is configured to store information handled by the terminal device 3 and various other devices in a memory area. This memory area is exemplified by the memory area (storage unit 32) of the terminal device 3 and the memory areas of various other devices, but this memory area does not necessarily have to be within the configuration shown in Figure 1, and the memory management unit 314 can also manage to store various information in an external memory device or the like.

[0035] 3. Details of the estimation method Next, the details of the estimation method of this embodiment will be described. Figure 4 is a flowchart showing the details of the estimation method of this embodiment. As shown in the flowchart of Figure 4, in the estimation method of this embodiment, as an acquisition step, the resistance value of the detection member 1 is acquired from the detection member 1 attached to the eyelid or surrounding skin of the subject SBJ (S1 in Figure 4). Here, the detection member 1 is a member with a thickness of 100 μm or less, having a conductive layer in at least a part of its structure. The resistance value is the resistance value of the conductive layer, which fluctuates as the detection member 1 expands and contracts in response to the movement of the skin.

[0036] In other words, in the acquisition process of this embodiment, a resistance value related to the detection member 1 is acquired from a predetermined detection member 1. The resistance value here is the resistance value related to the conductive layer (conductive layer 11) described later, and the resistance value of this conductive layer 11 fluctuates as the detection member 1 expands and contracts in response to the movement of the skin. In this embodiment, a predetermined device acquires this fluctuating resistance value. As an example shown in Figure 1, a resistance value acquisition device 2 acquires the resistance value and transmits it to a terminal device 3 (as a result, the terminal device 3 acquires the resistance value). The acquisition of the resistance value here may be the resistance value at a specific moment in time, or the resistance value over a period of time. When acquiring the resistance value over a period of time, the resistance value may be acquired intermittently or continuously.

[0037] Here, we will describe the detection member 1 involved in this acquisition process. As mentioned earlier, the detection member 1 is a member that is attached to the skin of the subject SBJ, and below we will describe its specific form in detail.

[0038] Figure 5 is a conceptual diagram showing how the detection member 1 is attached to the subject's SBJ. In the example shown in Figure 5, the detection member 1 is attached near the subject's eye EY (below the eye when the person is standing upright). The detection member 1 is attached to the subject's skin SK, and a skin contact layer 12 is present on the surface of the detection member 1 that is attached to the skin SK. A conductive layer 11 is laminated on the side of the detection member 1 opposite to the skin contact layer 12 that is in contact with the skin SK. In the example shown in Figure 5, the sheet SH and electrode E are pre-laminated on the skin SK, and the conductive layer 11 is positioned to be in contact with the electrode E. The sheet SH may be made of various materials, but one example is an insulating sheet. For example, a resin film such as a medical film may be used as the sheet SH. The electrode E may also be made of various conductive materials, but one example is a metal such as copper or gold, or a liquid metal. Furthermore, the diagram shows an embodiment in which a coating layer 13 is provided on the side of the conductive layer 11 of the detection member 1 opposite to the skin contact layer 12. In the example shown in Figure 5, the skin contact layer 12 and the coating layer 13 are shown to be connected at the proximal end of the detection member 1 relative to the eye EY, but the structure of the proximal end relative to the eye EY is not necessarily limited to this. For example, the proximal ends of the skin contact layer 12, the conductive layer 11, and the coating layer 13 relative to the eye EY may be aligned flush, or the proximal ends relative to the eye EY may be sealed with a material different from the skin contact layer 12 and the coating layer 13. In the example shown in Figure 5, wiring W is connected to electrode E, thereby enabling electrical conductivity with an external device.

[0039] In the estimation method of this embodiment, the detection member 1 has a conductive layer (conductive layer 11) in at least a part of its structure and is characterized by having a thickness of 100 μm or less. The thickness of the detection member 1 can be defined by the thickness from the contact surface of the detection member 1 with the skin SK to the outermost surface of the detection member 1. That is, the thickness T1 in the example shown in Figure 5 corresponds to the thickness of the detection member 1. In this embodiment, by setting the thickness of the detection member 1 low (making the detection member 1 thin), it becomes easier to precisely capture the movement around the eyes EY of the subject SBJ. In other words, by making the detection member 1 thin, it can be made easier to follow the movement of the subject SBJ's skin, which can contribute to improving the accuracy of resistance detection and the accuracy of gaze estimation. For example, in Non-Patent Literature 1 mentioned earlier, a polyethylene terephthalate (PET) resin layer with a base material of about 200 μm is used as a structure to be attached to the skin. When a base material with such thickness is used, it is considered that it becomes difficult to properly follow the stretching and contracting movements of the skin. The upper limit of the thickness (T1) of the detection member 1 may be 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, 10 μm or less, 5 μm or less, or 3 μm or less. In this way, by setting the thickness (T1) of the detection member 1 to a low value, the accuracy of resistance detection tends to increase. The lower limit of the thickness (T1) of the detection member 1 is not particularly limited, but for example, it may be 0.1 μm or more, or 0.3 μm or more.

[0040] In the detection member 1 of this embodiment, the conductive layer 11 may be made of various conductive materials. The conductive material here may be an organic material or an inorganic material.

[0041] The conductive organic material may include one or more organic materials selected from the group consisting of polythiophene, polypyrrole, polyaniline, and polybenzodifraione. The conductive material may also be a metal film, metal nanowire, carbon material such as carbon black, carbon nanotubes, or graphene. Furthermore, the conductive layer 11 may be formed by dispersing these conductive materials in a predetermined binder. The binder used here is preferably a highly flexible material, such as an elastomer.

[0042] The metal films and metal nanowires described above may be composed of various metals. Examples of metals that can constitute metal films and metal nanowires include gold, silver, copper, and titanium. When applying metal nanowires to the conductive layer 11, it is preferable to perform a treatment to deposit metal species between the metal nanowires so that they bond to each other. Specifically, this includes methods such as bonding the metal nanowires to each other after obtaining a fabricated object containing metal nanowires. The fabricated object here may typically be formed by applying an ink in which metal nanowires are dispersed. The formed object may then be immersed in a solution containing a metal salt, and then subjected to a treatment to reduce the metal salt. This can convert the metal salt into metal species that bond the metal nanowires to each other in the fabricated object. As a result, it becomes easier to obtain a material with appropriate mechanical strength when applied to the conductive layer 11. This treatment for bonding metal nanowires to each other may be called a "welding treatment". Furthermore, the metal ions contained in the above solution may be ions corresponding to the same metal as the metal constituting the metal nanowire, or ions corresponding to a different metal than the metal constituting the metal nanowire.

[0043] The shape of the metal nanowires can be set as appropriate, but for example, the average diameter may be in the range of 10 to 100 nm or in the range of 15 to 80 nm. Also, the average length of the metal nanowires may be in the range of 10 to 100 μm or in the range of 15 to 80 μm.

[0044] On the other hand, the elastomer that can be used in this embodiment may be an elastic polymer. Typically, this elastomer is a material that stretches when subjected to tension and returns to approximately its original length when the tension is removed. By using an elastomer as a binder to disperse a conductive material in this way, it becomes easier to obtain a conductive layer 11 that is easily expandable and has excellent durability.

[0045] Examples of elastomers that can be used include hydrocarbon-based elastomers such as natural rubber, isoprene rubber, nitrile rubber (NBR), ethylene propylene rubber (EPDM), styrene-butadiene rubber (SBR), butadiene rubber (BR), chloroprene rubber (CR), and styrene-butadiene-styrene (SBS) block polymers, as well as their hydrogenated elastomers; silicone elastomers; fluorine elastomers; urethane elastomers; acrylic elastomers; polyester elastomers; polyamide elastomers; and polyimide elastomers. These may be used individually or in combination of two or more. Alternatively, a composite elastomer formed by chemically bonding two or more elastomers may be used as the elastomer in this embodiment.

[0046] Furthermore, the elastomer of this embodiment may contain heteroatoms in its chemical structure. Here, heteroatoms are selected from the group consisting of, for example, nitrogen atoms, oxygen atoms, sulfur atoms, and halogen atoms. To give a more typical example, the elastomer of this embodiment may have chemical bonds containing heteroatoms in its chemical structure. That is, the elastomer of this embodiment may have one or more bonds selected from the group consisting of ether bonds, sulfide bonds, ester bonds, thioester bonds, amide bonds, and urethane bonds in its chemical structure.

[0047] Furthermore, the skin contact layer 12 and the coating layer 13 in the detection member 1 may be made of various materials, as long as they do not depart from the spirit of the present invention. On the other hand, since these layers are layers that can seal the conductive layer 11, it is also preferable to make them out of insulating materials. By doing so, the conductive layer 11 becomes less susceptible to the influence of the external environment, which can contribute to improving the accuracy of resistance detection. From another viewpoint, the skin contact layer 12 and the coating layer 13 may be layers containing elastomers. This makes it easier to improve the ability of the detection member 1 as a whole to follow the movement of the skin SK. In particular, by making the skin contact layer 12 (the contact surface of the detection member 1 with the skin SK) out of such an elastomer-containing layer, such an improvement in followability can be made particularly noticeable. The materials that can be used as elastomers are as described above. Also, when insulating properties are to be given to the skin contact layer 12 and the coating layer 13, the conductive materials described above may not be used (not incorporated) in these layers. Thus, the detection member 1 of this embodiment may have a laminated structure. Furthermore, the detection member 1 may be configured such that the conductive layer 11 is located on the side of the elastomer-containing layer (skin contact layer 12) opposite to the skin SK. This makes it easier to ensure the accuracy of detecting the resistance value of the conductive layer 11.

[0048] Furthermore, the detection member 1 can also be configured as follows. Figure 6 is a conceptual diagram showing the detection member 1 attached to the subject's SBJ. In the example shown in Figure 6, similar to Figure 5, the detection member 1 is attached near the subject's SBJ eye EY (below when a person is standing upright), but this detection member 1 is composed only of a conductive layer 11 (a single layer of conductive layer 11). In the example shown in Figure 6, wiring W is provided to this conductive layer 11, enabling the detection of the resistance value of the conductive layer 11.

[0049] The same material as the conductive layer 11 shown in Figure 5 can be used for this conductive layer 11. In other words, in one example, the conductive layer 11 may contain an elastomer. To put it another way, as mentioned earlier, the contact surface of the detection member 1 with the skin SK may be composed of a layer containing an elastomer, and in the example shown in Figure 6, this layer containing an elastomer corresponds to the conductive layer 11.

[0050] In this embodiment, the detection member 1 preferably has a low hardness in the layer containing the elastomer (skin contact layer 12 in Figure 5 or conductive layer 11 in Figure 6). For example, the Young's modulus at 25°C of the layer containing the elastomer in the detection member 1 is preferably 20 MPa or less, more preferably 15 MPa or less, even more preferably 10 MPa or less, and particularly preferably 5 MPa or less. By adopting such a Young's modulus for a predetermined layer of the detection member 1, the elasticity of the detection member 1 can be improved, and the accuracy of resistance detection can be further enhanced. On the other hand, there is no particular lower limit to the Young's modulus at 25°C of the layer containing the elastomer in the detection member 1, but as an example, it is 0.1 MPa or more. The Young's modulus at 25°C of the layer containing the elastomer can be defined from the relationship (gradient) between stress and strain in a tensile test. Furthermore, the Young's modulus at 25°C of the layer containing the elastomer can be evaluated (measured), for example, by preparing a test piece from the same material as the layer containing the elastomer and subjecting this test piece to a tensile test.

[0051] Furthermore, since the detection member 1 of this embodiment expands and contracts in accordance with the skin SK of the subject SBJ, it is preferable that the gauge coefficient of the strain gauge be within a predetermined range. For example, the gauge coefficient of the detection member 1 of this embodiment may be 0.05 or higher, or 0.1 or higher. There is no particular upper limit to the gauge coefficient, but as an example, it is 3 or less. The gauge coefficient here may be determined based on the relationship between the resistance value when the detection member 1 is not stretched (0% stretched state) and the resistance value when the detection member 1 is stretched by 1% (1% stretched state).

[0052] Furthermore, since the detection member 1 of this embodiment expands and contracts in accordance with the skin SK of the subject SBJ, it is preferable that it has excellent reusability. For example, it is preferable that the conductive layer 11 of the detection member 1 retains its conductive properties even when the process of stretching the detection member 1 from a 0% stretched state to a 1% stretched state is repeated 100 times.

[0053] Furthermore, it is preferable that the detection member 1 of this embodiment has low humidity dependence and temperature dependence.

[0054] As an example, the detection member 1 of this embodiment is preferably a member whose HCR value (HCR value) shown by the following formula (1) is 0.002 / % or less. HCR = ΔR / (ΔH·R0) ··· (1) In this equation (1), ΔH is the percentage change in humidity when the humidity is changed, with 20% humidity as the baseline; R0 is the resistance value of the conductive layer 11 when the humidity of the measurement environment of the detection member 1 is 20%; and ΔR is the change in the resistance value of the conductive layer 11 from when the humidity was 20% due to the change in humidity.

[0055] Furthermore, the detection member 1 of this embodiment is preferably a member whose TCR value (TCR value) shown by the following formula (2) is 0.003 / ℃ or less. TCR = ΔR / (ΔT·R0) ··· (2) In equation (2), ΔT is the amount of temperature change when the temperature is changed relative to 5°C, R0 is the resistance value of the conductive layer 11 when the detection member 1 is placed at 5°C, and ΔR is the amount of change in the resistance value of the conductive layer 11 when the temperature of the detection member 1 changes from 5°C.

[0056] Such a detection member 1 is attached to the skin SK by various methods. On the other hand, as mentioned above, the thickness of the detection member 1 is less than or equal to a predetermined value, so the following steps may be taken to ensure stable attachment of the detection member 1. That is, the estimation method of this embodiment may further include a preparation step and an attachment step. In the preparation step, an attachment laminate 4 in which the detection member 1 and a release film 5 are laminated may be prepared. In the attachment step, the side of the attachment laminate 4 in which the detection member 1 is present is attached to the skin SK, and after the attachment laminate 4 is attached to the skin SK, the release film 5 is removed to attach the detection member 1 to the skin SK. The attachment laminate 4 and the method of attaching the detection member 1 using this attachment laminate 4 will be described below.

[0057] Figure 7 is a cross-sectional view illustrating the adhesive laminate 4 in this embodiment. As previously mentioned, the adhesive laminate 4 can be prepared by laminating a detection member 1 and a release film 5. Specifically, Figure 7 shows an adhesive laminate 4A in which the release film 5 is laminated to the detection member 1 shown in Figure 5, and an adhesive laminate 4B in which the release film 5 is laminated to the detection member 1 shown in Figure 6. However, the specific structure of the adhesive laminate 4 is not limited thereto and can be modified as appropriate depending on the configuration of the detection member 1, etc. In this embodiment, the detection member 1 is used for electrical extraction, etc., and in one embodiment, the conductive layer 11 of the detection member 1 may be exposed to the outside in the adhesive laminate 4.

[0058] Such adhesive laminates 4 are manufactured and prepared by various methods. For example, a release film 5 is formed on the surface of a predetermined substrate (such as a glass substrate), and then a detection member 1 is formed to be laminated onto the release film 5. After the detection member 1 is laminated, the adhesive laminate 4 can be obtained by peeling the laminate from the substrate. If the detection member 1 has a laminated structure, the lamination should be carried out on the release film 5 starting from the layer furthest from the layer that will come into contact with the skin SK. When forming the release film 5 on the surface of the substrate, various coating techniques such as spin coating, inflation, T-die, casting, calendering, and extrusion can be used.

[0059] The thickness of the release film 5 of the adhesive laminate 4 shown in Figure 7 may be set appropriately according to the ease of application, etc. For example, the average thickness of the release film 5 may be in the range of 1 to 50 μm, 3 to 40 μm, or 5 to 30 μm.

[0060] The release film 5 may be removed by various methods. In one embodiment, the release film 5 is mechanically peeled off after the application operation. Alternatively, the release film 5 may be dissolved and removed by a solvent (including water and organic solvents) after the application operation. In one embodiment, the release film 5 may be made of a water-soluble material. The embodiment of removal by a solvent will be described in detail below.

[0061] In other words, assuming a system in which the release film 5 is removed by water, the release film 5 may contain a water-soluble material (especially a water-soluble polymer). Such a water-soluble polymer can be appropriately selected from various materials. Examples of water-soluble polymers include polyvinyl alcohol, polyvinylpyrrolidone, starch, methylcellulose, and carboxymethylcellulose. Of these, from the viewpoint of achieving high performance as a release film 5, it is preferable that the release film 5 contains polyvinyl alcohol (hereinafter sometimes abbreviated as PVA). Here, PVA is generally obtained by saponifying polyvinyl acetate. The degree of saponification can be appropriately set depending on the application.

[0062] On the other hand, in a system where the exfoliation film 5 is removed by an organic solvent, the exfoliation film 5 is composed of a material that is soluble in the organic solvent used. The organic solvent can be one or more of the following: alcohol-based solvents, ketone-based solvents, ester-based solvents, ether-based solvents, ether-ester-based solvents, glycol-ether-based solvents, amide-based solvents, carbonate-based solvents, etc.

[0063] Next, a method of attachment using such an adhesive laminate 4 will be explained with reference to Figures 8 and 9. Figure 8 is a conceptual diagram showing an example of the attachment method according to this embodiment. Figure 9 is a conceptual diagram showing an example of the attachment method according to this embodiment.

[0064] First, let's explain the example shown in Figure 8. In this example, a sheet SH is first placed on the skin SK, and an electrode E is laminated on top of it (see Figure 8(a)). Then, after preparing the adhesive laminate 4A as shown in Figure 7, the side of the adhesive laminate 4A opposite to the side with the release film 5 is attached to the skin SK (see Figure 8(b)). Note that the attachment here is done so that the conductive layer 11 of the detection member 1 and the electrode E are in contact. Then, by mechanically removing (peeling off) the release film 5, it becomes possible to stably attach the detection member 1 to the skin SK (see Figure 8(c)).

[0065] Next, let's explain the example shown in Figure 9. This example in Figure 9 is the same as in Figures 8(a) and (b) until the side of the adhesive laminate 4A opposite to the side with the release film 5 is attached to the skin SK. However, it includes a step of removing the release film 5 by dissolving it with water. In other words, a process is performed in which a water-soaked fiber or the like (referred to as "water WT" for convenience) is brought into contact with the release film 5 exposed on the surface (see Figure 8(c)). As mentioned above, if the release film 5 contains a water-soluble material, the release film 5 is dissolved and removed by this water WT, and as a result, the detection member 1 is attached to the skin SK (see Figure 8(d)). After attaching the detection member 1 to the skin SK according to the process shown in Figures 8 and 9, electrical conductivity to the detection member 1 is made possible by providing wiring W to the electrode E. Then, in the acquisition step of this embodiment, the resistance value can be obtained from the detection member 1 attached in the attachment step.

[0066] Let's return to the flow of the estimation method in this embodiment. After obtaining the resistance value as described above, the estimation step involves estimating the gaze of the subject SBJ based on the obtained resistance value and pre-set reference information (S2 in Figure 4). Here, the reference information is information that associates the resistance value with the gaze of the subject SBJ.

[0067] In other words, the estimation method of this embodiment estimates the gaze direction of the subject SBJ from the acquired resistance value based on predetermined reference information. In one example, the estimation unit 312 of the terminal device 3 performs this estimation process. The reference information used in the estimation step may be a pre-modeled relationship (estimation model) between the resistance value related to the detection member 1 and the gaze direction of the subject SBJ. The estimation model here may be, for example, a function that shows the relationship between the two, a lookup table, or a trained model that has learned the relationship between the two. That is, by inputting the resistance value acquired in the acquisition step into the estimation model, the estimation model may output information regarding the gaze direction of the subject SBJ.

[0068] Regarding such estimation models, the relationship between the resistance value of the detection member 1 and the gaze of the subject SBJ can be analyzed based on known analytical methods. Typically, a desired estimation model can be obtained by analyzing it using regression analysis methods (linear models, generalized linear models, generalized linear mixed models, ridge regression, lasso regression, elastic networks, support vector regression, projection tracking regression, etc.), time series analysis (VAR models, SVAR models, ARIMAX models, SARIMAX models, state-space models, etc.), decision trees (decision trees, regression trees, random forests, XGBoost, etc.), neural networks (simple perceptrons, multilayer perceptrons, DNNs, CNNs, RNNs, LSTMs, etc.), Bayesian methods (naive Bayes, etc.), clustering (k-means, k-means++, etc.), ensemble learning (Boosting, Adaboost, etc.), etc.). In addition, the reference information used in the estimation method of this embodiment may be the reference information defined above.

[0069] Furthermore, if multiple detection members 1 are attached to the subject SBJ, the subject SBJ's line of sight may be estimated based on each of the attached detection members 1. In other words, the reference information described above may estimate the subject SBJ's line of sight based on two or more resistance values.

[0070] The gaze direction of the subject SBJ estimated as described above may be displayed on a predetermined display device (including the output unit 35 of the terminal device 3) based on the functions of the display control unit 313 of the terminal device 3. When such a display is made, predetermined visual information may be generated based on the estimated gaze direction of the subject SBJ. It is also possible to control external devices, etc., by using the information regarding the estimated gaze direction of the subject SBJ as a predetermined signal. For example, it is possible to operate an avatar displayed on the screen of a predetermined display device based on the information regarding the estimated gaze direction of the subject SBJ. In addition, the information regarding the estimated gaze direction of the subject SBJ may be stored in a predetermined memory area based on the functions of the memory management unit 314 of the terminal device 3. It is also possible to tune the estimation model described above based on the information stored in this way.

[0071] 4. Shape of the detection member 1 Next, the shape of the detection member 1 will be described. In the estimation method of this embodiment, the shape of the detection member 1 may be arbitrarily set as long as the thickness T1 satisfies predetermined conditions. The conductive layer 11 provided on the detection member 1 may also have an arbitrary shape. For example, the conductive layer 11 of the detection member 1 may have various shapes such as circular, elliptical, polygonal, etc., when viewed in plan view of the detection member 1 (viewed from the direction normal to the surface of the attached skin SK). Various microfabrication techniques may be used to form such shapes of conductive layer 11. For example, the molded object formed from the material constituting the conductive layer 11 can be deformed into a desired shape by etching or laser processing. When performing such etching or laser processing, a mask (e.g., a resist material) may be applied to the conductive layer 11 before the various processes are carried out. The applied mask may be peeled off (removed) after the various processes are carried out. In addition, if the conductive layer 11 is a photosensitive material, the conductive layer 11 of a desired shape can be formed by photolithography. For example, the conductive layer 11 of a desired shape can be formed by selectively exposing the photosensitive material through a photomask and then developing it.

[0072] In this embodiment, the conductive layer 11 of the detection member 1 may be a linear pattern. In this linear pattern, the "line" has a shape with length and width, and typically the length is greater than the width.

[0073] The line width when forming the conductive layer 11 as a line pattern can be set as appropriate. For example, the line width of the line pattern may be in the range of 5 μm to 5 mm, 30 μm to 2 mm, or 50 μm to 1 mm. By setting it within such a range, the strength of the conductive layer 11 can be ensured while improving the efficiency of resistance detection.

[0074] The conductive layer 11 having such a linear pattern will be explained with reference to the figures. Figure 10 is a schematic diagram illustrating the shape of the conductive layer 11 in this embodiment. The conductive layer 11, which constitutes part (or all) of the detection member 1, is arranged as a linear pattern near the eye EY of the subject SBJ. The linear pattern here may be a linear pattern that extends in a straight line from one point to another. On the other hand, the linear pattern may have a folded structure. That is, the linear pattern in this embodiment may have a structure that includes a first line portion through which electricity flows along a first direction, a second line portion through which electricity flows in the opposite direction to the first direction, and a connecting portion that connects the first line portion and the second line portion. The first direction here may be the direction along which the skin SK moves.

[0075] As explained using the example shown in Figure 10, the conductive layer 11 has a structure comprising a first line portion 111 through which electricity flows in a first direction (D1), a second line portion 112 through which electricity flows in the opposite direction to the first direction (D1), and a connecting portion (first connecting portion 113) that connects the first line portion 111 and the second line portion 112. In the example shown in Figure 10, the first connecting portion 113 is provided at the end of the conductive layer 11 closer to the eye EY, but the position of the first connecting portion 113 is not necessarily limited to this. That is, the first connecting portion 113 may be provided at the end of the conductive layer 11 further from the eye EY. Note that Figure 10 schematically shows the structure of only the conductive layer 11 in the detection member 1, but as mentioned above, the detection member 1 may include layers other than the conductive layer 11. In other words, although not explicitly shown in Figure 10, layers corresponding to the skin contact layer 12 and the coating layer 13 shown in Figure 5 may be laminated on the conductive layer 11 shown in Figure 10.

[0076] Furthermore, in this case, the first direction (D1) is the direction along the direction of movement of the skin SK. Here, the "direction of movement of the skin SK" is typically the direction in which the skin SK expands and contracts in accordance with the movement of the eye EY. For example, the "direction of movement of the skin SK" may correspond to the evaluation axis when performing gaze estimation. Also, the "direction along the direction of movement of the skin SK" does not necessarily have to be parallel to the direction of movement of the skin SK, and a certain inclination is acceptable. For example, when viewing the face of the subject SBJ from the front, if the angle (acute angle) at which the "first direction" and the "direction of movement of the skin SK" intersect is defined, then the first direction can be said to be the direction along the direction of movement of the skin SK if the angle is 30° or less, 25° or less, 20° or less, 15° or less, or 10° or less.

[0077] Furthermore, the conductive layer 11 may have the structure shown in Figure 11. Figure 11 is a schematic diagram illustrating the shape of the conductive layer 11 in this embodiment. The conductive layer 11 (conductive layer 11A) shown in Figure 11 has a structure similar to that shown in Figure 10, having a first line portion 111 through which electricity flows in a first direction (D1), a second line portion 112 through which electricity flows in the opposite direction to the first direction (D1), and a connecting portion (first connecting portion 113) that connects the first line portion 111 and the second line portion 112. On the other hand, in the example of the conductive layer 11A shown in Figure 11, a second connecting portion 114 is provided opposite the first connecting portion 113, and as a result, it has the characteristic of having multiple first line portions 111 (three in the example of Figure 11). By increasing the number of first line portions 111 (or second line portions 112) in this way, the accuracy of detecting the resistance value associated with the expansion and contraction of the skin SK is improved. The number of first connecting portions 113 and second connecting portions 114 is not limited to those shown in Figure 11, and can be appropriately set according to the convenience of attaching the detection member 1 and the detection accuracy for which the resistance value is required (that is, the conductive layer 11 may have two or more first connecting portions 113 and two or more second connecting portions 114).

[0078] Furthermore, as shown in Figure 11, multiple detection members 1 may be attached to one eye EY (multiple for both eye EYs). In such cases, each detection member 1 may be attached in an appropriate direction (preferably "a direction along the direction of movement of the skin SK"). As mentioned earlier, the first direction (D1) for the detection member 1 may be defined based on its relationship to the axis used to evaluate the line of sight. As shown in the example in Figure 11, by attaching multiple detection members 1 to the subject SBJ, the line of sight can be estimated based on two or more axes. In the example shown in Figure 11, the detection member 1 having a conductive layer 11A can be responsible for estimating the horizontal direction of the eye EY, and the detection member 1 having a conductive layer 11B can be responsible for estimating the vertical direction of the eye EY. That is, in Figure 11, the first direction (D1) in the conductive layer 11A is along the horizontal direction corresponding to "the direction of movement of the skin SK", and the first direction (D1') in the conductive layer 11B is along the vertical direction corresponding to "the direction of movement of the skin SK". In this way, the subject's line of sight can be estimated by associating it with coordinate information (two-dimensional information) as viewed from directly in front of the subject.

[0079] 5. Others Although embodiments of the present invention have been described above, the present invention is not limited thereto and can be modified as appropriate without departing from the technical spirit of the invention.

[0080] In the above embodiment, terminal device 3 performed various storage and control functions, but multiple external devices may be used instead of terminal device 3. That is, various information and programs may be stored in a distributed manner across multiple external devices using blockchain technology or the like.

[0081] On the other hand, in the above embodiment, the functions of the resistance value acquisition device 2 and the terminal device 3 were separated, but the acquisition of resistance values ​​and the estimation of the subject SBJ's gaze may be performed by a single device. For example, a processor in a device that can be worn by the subject SBJ may perform both the acquisition of resistance values ​​related to the detection member 1 and the estimation of the subject SBJ's gaze. Furthermore, such a device that can be worn by the subject SBJ may generate various visual information based on the estimated gaze and display various visual information to the subject SBJ, etc.

[0082] In the above embodiment, an example was shown where the subject SBJ was a human, but the subject SBJ may also include animals other than humans. For example, it is possible to estimate the gaze of animals such as dogs and cats based on the estimation method of this embodiment.

[0083] The embodiments of this model are not limited to estimation methods, but may also be estimation systems or programs. An estimation system is a system comprising an acquisition unit 311 and an estimation unit 312. A program is a program that causes a computer to execute each of the acquisition and estimation steps in the estimation method.

[0084] The product may be provided in any of the following embodiments.

[0085] (1) A method for estimating the gaze of a subject, comprising an acquisition step and an estimation step, wherein in the acquisition step, a resistance value related to a detection member is acquired from a detection member attached to the eyelid or surrounding skin of the subject, where the detection member is a member having a thickness of 100 μm or less and having a conductive layer in at least a part of its structure, and the resistance value is the resistance value of the conductive layer which changes as the detection member expands and contracts in response to the movement of the skin, and in the estimation step, the gaze of the subject is estimated based on the acquired resistance value and a preset reference information, where the reference information is information that associates the resistance value with the gaze of the subject.

[0086] (2) The method according to (1) above, wherein the contact surface of the detection member with respect to the skin is composed of a layer containing an elastomer.

[0087] (3) The method according to (2) above, wherein the detection member has a laminated structure, and the conductive layer is located on the side of the layer containing the elastomer that is opposite to the skin.

[0088] (4) The method according to (2) above, wherein the layer containing the elastomer corresponds to the conductive layer.

[0089] (5) A method according to any one of (2) to (4) above, wherein the Young's modulus of the layer containing the elastomer at 25°C is 20 MPa or less.

[0090] (6) A method according to any one of (1) to (5) above, wherein the conductive layer is a linear pattern.

[0091] (7) The method according to (6) above, wherein the linear pattern has a structure comprising a first line portion through which electricity flows along a first direction, a second line portion through which electricity flows in the opposite direction to the first direction, and a connecting portion connecting the first line portion and the second line portion, wherein the first direction is the direction along the direction of skin movement.

[0092] (8) A method according to any one of (1) to (7) above, wherein in the acquisition step, a resistance value related to the detection member is acquired from each of the two or more detection members, and in the estimation step, the gaze of the subject is estimated based on the two or more acquired resistance values.

[0093] (9) A method according to any one of (1) to (8) above, further comprising a preparation step and an attachment step, wherein in the preparation step, an attachment laminate is prepared in which the detection member and a release film are laminated; in the attachment step, the side of the attachment laminate in which the detection member is present is attached to the skin; after the attachment laminate is attached to the skin, the release film is removed to attach the detection member to the skin; and in the acquisition step, the resistance value is acquired from the detection member attached by the attachment step.

[0094] (10) The method according to (9) above, wherein the release film is made of a water-soluble material, and in the application step, the release film is removed by dissolving the release film with water.

[0095] (11) A detection member used in the method described in any one of (1) to (10) above. Of course, this is not always the case. [Examples]

[0096] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples.

[0097] [Attachment of detection member 1] First, a medical film (product name "Airwall Fuwari"; manufactured by Kyowa Co., Ltd.) was applied to the facial skin of the subject (subject SBJ), and then electrodes were formed on this medical film using liquid metal. Next, a detection member 1 having the cross-sectional structure shown in Figure 5 was attached to the subject's skin so that the conductive layer 11 was in contact with the electrodes. In this embodiment, a laminate for attachment was obtained by placing paper on the coating layer 13 side of the detection member 1, and after attaching the laminate for attachment to the subject's skin, the paper was peeled off to attach the detection member 1 to the subject's skin.

[0098] In this embodiment, the constituent materials and thicknesses of each layer of the detection member 1 are as shown in Table 1 below. In this embodiment, the "acrylic thermoplastic elastomer" used is product name: Clarity® LA2330 (manufactured by Kuraray Co., Ltd.), and the "hydrogen ethylene thermoplastic elastomer" used is product name: ToughTec® H1221 (manufactured by Asahi Kasei Corporation).

[0099] [Table 1]

[0100] Furthermore, in this embodiment, the conductive layer 11 has a serpentine structure in plan view. Figure 12 is a photograph showing the detection member attached in this embodiment. As shown in Figure 12, in this embodiment, the obtained sensor (detection member 1) is attached to a subject and verified in the manner shown as S1 and the manner shown as S2. Specifically, the detection member 1 is attached to the subject so that the reciprocating line portion of the conductive layer 11 (corresponding to the first line portion 111 and the second line portion 112) follows the double-headed arrow in the figure.

[0101] [Resistance detection] As described above, after attaching the detection member 1 to the subject, the subject's gaze was moved, and the resistance value corresponding to each gaze direction was detected. Figure 13 is a graph showing the resistance values ​​detected by the detection member in the embodiment. Figure 13(a) shows the resistance value detected by the detection member 1 shown as S1, and Figure 13(b) shows the resistance value detected by the detection member 1 shown as S2. In this embodiment, it is assumed that the vertical eye movement ranges from -20° to 20°, and the horizontal eye movement ranges from -40° to 40°, and the data shows how the resistance value detected by the detection member 1 changes when the pupil is at each angle (see the lower illustration in Figure 13). In this embodiment, the data when the gaze direction is moved horizontally while the vertical position is fixed is summarized in Figure 13. As shown in Figure 13(a), when the detection member 1 is attached in the manner of S1, the resistance value changes according to the horizontal eye movement. Furthermore, when the detection member 1 is attached in the manner of S1, it can be seen that a more pronounced change in resistance value occurs in response to vertical line of sight movement compared to when the detection member 1 is attached in the manner of S2. On the other hand, as shown in Figure 13(b), when the detection member 1 is attached in the manner of S2, a particularly pronounced change in resistance value is observed in response to vertical eye movement. It is suggested that by increasing the proportion of the resistance value that changes in this way, more precise line of sight estimation becomes possible. In other words, when the conductive layer 11 is a line-shaped pattern, it is suggested that more precise line of sight estimation becomes possible by aligning the length direction of the line (first direction) with the axis used when estimating the line of sight (bringing it closer to the axis used when estimating the line of sight).

[0102] Finally, while various embodiments relating to this disclosure have been described, these are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0103] 1, 1A, 1B: Detection members 2: Resistance measurement device 3: Terminal device 4: Laminate for adhesive application 4A, 4B: Laminate for adhesive application 5: Exfoliation film 11, 11A, 11B: Conductive layer 12: Skin contact layer 13: Covering layer 31: Control Unit 32: Storage section 33: Communications Department 34: Input section 35: Output section 36: Communications bus 111: First line area 112: Second line area 113: 1st connection site 114:Second connection site 311: Acquisition Department 312: Estimation section 313: Display Control Unit 314: Memory management department E: Electrode EY: Eye SBJ: Target audience SH: Seat SK:Skin T1: Thickness W: Wiring WT:Water

Claims

1. A method for estimating the gaze of a subject, It comprises an acquisition process and an estimation process, In the acquisition step, the resistance value of the detection member is obtained from the detection member attached to the eyelid or surrounding skin of the subject, Here, the detection member is a member having a conductive layer in at least a part of its structure and a thickness of 100 μm or less. The aforementioned resistance value is the resistance value of the conductive layer, which fluctuates as the detection member expands and contracts in response to the movement of the skin. In the estimation step, the gaze of the subject is estimated based on the acquired resistance value and the pre-set reference information. Here, the reference information is information that associates resistance value with the subject's gaze, in this method.

2. In the method according to claim 1, A method wherein the contact surface of the detection member with respect to the skin is composed of a layer containing an elastomer.

3. In the method of claim 2, The detection member has a laminated structure, and the conductive layer is located on the side of the elastomer-containing layer opposite to the skin.

4. In the method of claim 2, A method wherein the layer containing the elastomer corresponds to the conductive layer.

5. In the method of claim 2, A method wherein the Young's modulus of the layer containing the elastomer is 20 MPa or less at 25°C.

6. In the method according to claim 1, The conductive layer is in the form of a linear pattern.

7. In the method according to claim 6, The aforementioned linear pattern is, A first line portion through which electricity flows along the first direction, A second line portion in which electricity flows in the opposite direction to the first direction, A connecting portion that connects the first line portion and the second line portion, It is a structure having the following characteristics: A method wherein the first direction is a direction along the direction of the movement of the skin.

8. In the method according to claim 1, In the acquisition step, the resistance value related to the detection member is acquired from each of the two or more detection members. The estimation step involves estimating the gaze of the subject based on two or more resistance values ​​obtained.

9. In the method according to claim 1, The preparation process and the application process are further included. In the preparation step, a laminate for attachment is prepared in which the detection member and the release film are laminated together. In the application process, the side of the adhesive laminate containing the detection member is applied to the skin, and after applying the adhesive laminate to the skin, the release film is removed, thereby applying the detection member to the skin. The acquisition step is a method for acquiring the resistance value from the detection member that has been attached by the attachment step.

10. In the method according to claim 9, The aforementioned release film is composed of a water-soluble material. The method for removing the release film in the application step is to dissolve the release film with water.

11. A detection member, A detection member used in the method according to any one of claims 1 to 10.

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