Movement detection device

Abstract

To provide a movement detection device capable of detecting an analog movement of a facial surface.SOLUTION: A structure is attached to a human head. A capacitive sensor is mounted on the structure. The capacitive sensor includes: a detection electrode facing skin of the head where the structure is attached, with a space therebetween; and a detection circuit that outputs a detection signal changing in response to a change in capacitance between the detection electrode and the skin.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a motion sensing device. [Background technology]

[0002] There is known an input device that detects the movement of a user's cheek with a touch sensor and uses it as an input operation to an external computer (Patent Document 1). In this input device, whether or not the user's cheek has touched the touch sensor is detected by detecting a change in capacitance between the user's cheek, which is applied with a ground potential, and a conductive cloth. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-125479 A Summary of the Invention [Problem to be solved by the invention]

[0004] Although conventional input devices can detect whether a user's cheek has touched a touch sensor, they cannot detect analog cheek movements, such as the degree to which the cheek is puffed out. Conventional input devices can perform digital input, such as mouse clicks, but cannot be used as input devices that perform some operation using analog movements.

[0005] An object of the present invention is to provide a movement detection device capable of detecting analog movement of the surface of a face. [Means for solving the problem]

[0006] According to one aspect of the present invention, A structure to be attached to the head of a human body; A capacitance sensor mounted on the structure; Equipped with The capacitance sensor includes: A detection electrode facing the skin of the head on which the structure is attached, with a gap therebetween; and a detection circuit that outputs a detection signal that changes in response to a change in capacitance between the detection electrode and the skin. Effect of the Invention

[0007] By detecting the change in capacitance between the detection electrode and the skin, analog movements of the face surface can be detected. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view showing a part of a motion detection device according to a first embodiment together with a human head. [Diagram 2] FIG. 2 is a cross-sectional view of the motion detection device according to the first embodiment. [Diagram 3] FIG. 3A is a block diagram of a motion detection device according to a first embodiment, and FIG. 3B is a block diagram of a detection circuit. [Figure 4] FIG. 4 is an equivalent circuit diagram of the motion detection device according to the first embodiment. [Diagram 5] FIG. 5 is a graph showing an example of waveforms of the excitation voltage ve and the detection voltage vd. [Figure 6] FIG. 6 is a flowchart illustrating the operation of the motion detection device according to the first embodiment. [Figure 7] Figure 7A is a graph showing the change in amplitude Vd of the detected voltage vd over time when the sounds "a," "i," "u," "e," and "o" are uttered in order, Figure 7B is a graph showing the change in amplitude Vd of the detected voltage vd over time when the lower jaw is moved from side to side, and Figure 7C is a graph showing the change in amplitude Vd of the detected voltage vd over time when the eyelids are opened and closed. [Figure 8] FIG. 8 is a schematic perspective view of a structure in which the motion detection device according to the second embodiment is worn on the head. [Figure 9]FIG. 9 is a plan view of the motion detection device according to the second embodiment, with the structure of the motion detection device laid out on a plane. [Figure 10] FIG. 10 is a perspective view of a motion detection device according to the third embodiment. [Figure 11] FIG. 11 is a perspective view of a motion detection device according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [First Example] A motion detection device according to a first embodiment will be described with reference to FIGS. 1 to 7C. Fig. 1 is a schematic perspective view showing a part of a motion detection device 10 according to a first embodiment together with a human head 70. The motion detection device 10 according to the first embodiment includes a mask-shaped structure 20, and a plurality of detection electrodes 31, excitation electrodes 32, etc. attached to the structure 20. In Fig. 1, the detection electrodes 31 are hatched.

[0010] The structure 20 includes a covering portion 20A and two mask strings 20B. When the two mask strings 20B are hung around the left and right ears of a human head 70, respectively, the covering portion 20A covers the lips 71 of the head 70 and the skin around them. Fig. 1 shows a state in which the right mask string 20B (not shown in Fig. 1) is hung around the right ear and the left mask string 20B is removed from the ear.

[0011] A plurality of detection electrodes 31 are disposed on the inner surface of the covering part 20A. When the structure 20 is attached to the head 70, the plurality of detection electrodes 31 face the lips 71 and the skin around them at intervals. An excitation electrode 32 is attached to one of the mask strings 20B. When the structure 20 is attached to the head 70 with the mask strings 20B hanging around the ears, the excitation electrode 32 comes into contact with the skin of the head 70. This causes the excitation electrode 32 and the head 70 to have approximately the same electrical potential.

[0012] 2 is a cross-sectional view of the covering portion 20A of the motion detection device 10 according to the first embodiment. A mesh-shaped ground electrode 33 is disposed inside (on the head 70 (FIG. 1) side) of the covering portion 20A of the structure 20 (FIG. 1), and a plurality of detection electrodes 31 are disposed inside the ground electrode 33. An insulating fabric 20C is provided between the ground electrode 33 and the plurality of detection electrodes 31, and inside the plurality of detection electrodes 31. When viewed from the head 70 (FIG. 1) side, the detection electrode 31 is disposed at a position overlapping with the ground electrode 33, and the ground electrode 33 is disposed farther away than the detection electrode 31.

[0013] 3A is a block diagram of the motion detection device 10 according to the first embodiment. The motion detection device 10 according to the first embodiment includes a capacitance sensor 30, a processing unit 40, a wireless communication circuit 41, and a battery 42. The capacitance sensor 30 includes a plurality of detection electrodes 31, an excitation electrode 32, a ground electrode 33, a plurality of detection circuits 34, and an excitation circuit 35. The detection circuit 34, the excitation circuit 35, the processing unit 40, the wireless communication circuit 41, and the battery 42 are attached to, for example, the structure 20 (FIG. 1). For example, they are attached to a location that does not interfere with the attachment of the structure 20, such as near the edge on either the left or right side of the covering portion 20A.

[0014] The ground electrode 33 provides a reference potential to the detection circuit 34 and the excitation circuit 35. Five detection electrodes 31 are shown in Fig. 1, but three detection electrodes 31 are shown in Fig. 3A. The number of detection electrodes 31 may be one or more.

[0015] The excitation electrode 32 comes into contact with the skin of the head 70. This causes the excitation electrode 32 and the head 70 to have approximately the same potential.

[0016] The excitation circuit 35 outputs a preset excitation voltage v e is generated and applied to the excitation electrode 32. e is an AC voltage, such as a pulse waveform or a sine waveform. The excitation voltage v e The frequency of the excitation voltage v eThe frequency may be, for example, in the range of 100 Hz to 1 MHz.

[0017] The detection circuit 34 is provided for each detection electrode 31 and is connected to the detection electrode 31. The detection circuit 34 detects the excitation voltage v e A voltage (hereinafter, the detection voltage v d Based on the detection signal S d Instead of providing a detection circuit 34 for each detection electrode 31, a configuration may be adopted in which one detection circuit 34 or fewer detection circuits 34 than the number of detection electrodes 31 are provided, and each detection circuit 34 is connected to the detection electrode 31 via a switch. In this case, each detection circuit 34 generates a detection voltage V d is detected in a time-division manner, and the detection signal S d Generate.

[0018] The processing unit 40 controls the excitation circuit 35 to generate the excitation voltage v e and the detection signal S from the detection circuit 34 d The signal processing result is transmitted to an external device via a wireless communication circuit 41. A battery 42 provides a power supply voltage to each electronic circuit in the motion detection device 10.

[0019] 3B is a block diagram of the detection circuit 34. The detection voltage v generated at the detection electrode 31 d is input to an amplifier circuit 34A having a high input impedance. An amplitude detection circuit 34B detects the amplitude of the signal amplified by the amplifier circuit 34A and outputs an analog signal representing the amplitude. An AD conversion circuit 34C converts the analog signal representing the amplitude into a digital signal. The converted digital signal is input to a processing unit 40.

[0020] FIG. 4 is an equivalent circuit diagram of the motion detection device 10 according to the first embodiment. FIG. 4 shows one of the multiple detection electrodes 31. The parasitic capacitance between the detection electrode 31 and the head 70 (hereinafter referred to as the detection capacitance) is C detWhen the facial expression of the head 70 is changed, the distance between the detection electrode 31 and the skin of the head 70 changes. The change in the distance between the detection electrode 31 and the skin of the head 70 causes the detection capacitance C det also changes.

[0021] The parasitic capacitance between the excitation electrode 32 and the head 70 is C c In the first embodiment, the excitation electrode 32 is in contact with the skin of the head 70, so that the parasitic capacitance C c The portion is substantially short-circuited. Here, the "state where the excitation electrode 32 is in contact with the skin" includes not only the state where the metal part of the excitation electrode 32 is in direct contact with the skin, but also the state where an insulating protective film is formed on the surface of the metal part of the excitation electrode 32 and this protective film is in contact with the skin.

[0022] When the protective film of the excitation electrode 32 is in contact with the skin, the metal part of the excitation electrode 32 faces the skin via the protective film. In this case, strictly speaking, the excitation electrode 32 is not short-circuited to the head 70. However, the parasitic capacitance C c is the detection capacitance C det Since the parasitic capacitance Cc is sufficiently large compared to the capacitance Cc, the location of the parasitic capacitance Cc can be considered to be substantially short-circuited.

[0023] Parasitic capacitance C from excitation electrode 32 c , head 70 and detection capacitance C det The resistance component of the current path to the detection electrode 31 via the b The parasitic capacitance between the detection electrode 31 and the excitation electrode 32 is denoted as C ab , the parasitic capacitance between the excitation electrode 32 and the ground electrode 33 is C bg , the parasitic capacitance between the detection electrode 31 and the ground electrode 33 is C ag As shown in FIG. 1, the distance from the ground electrode 33 (FIG. 2) to the excitation electrode 32 is sufficiently longer than the distance from the ground electrode 33 (FIG. 2) to the detection electrode 31, the distance from the detection electrode 31 to the skin of the head 70, and the distance from the excitation electrode 32 to the skin of the head 70. For this reason, the parasitic capacitance C bgis the parasitic capacitance C ag , detection capacitance C det , parasitic capacitance C c is much smaller than

[0024] The excitation circuit 35 applies an excitation voltage v e The detection circuit 34 applies a detection voltage v to the detection electrode 31. d and detects the detection voltage v d The amplitude of V d The detection signal S according to d Generate.

[0025] Figure 5 shows the excitation voltage v e and the detection voltage v d 1 is a graph showing an example of a waveform of an excitation voltage v e The waveform of is a pulse that rises from negative potential to positive potential at time t1 and falls back to the original negative potential at time t3. This pulse waveform is repeated at angular frequency ω. The height of this pulse waveform is the excitation voltage v e The amplitude of V e is equivalent to.

[0026] Detection voltage v d is the excitation voltage v e The detection voltage v d The rising waveform of the detection voltage v is determined based on a time constant (hereinafter referred to as the charging time constant) determined by the output impedance of the excitation circuit 35, the combined capacitance from the excitation electrode 32 to the ground electrode 33, etc. d is the input impedance of the detection circuit 34, and the parasitic capacitance C ag The parasitic resistance and parasitic capacitance C ag The detection circuit 34 has a high input impedance, so the discharge time constant is sufficiently long compared to the charge time constant. Therefore, the detection voltage v d starts to rise at time t1 in accordance with the charging time constant, then reaches a maximum value at time t2, and thereafter gradually decreases in accordance with the discharging time constant.

[0027] Excitation voltage v at time t3 e In synchronization with the falling edge of d At this time, the excitation voltage v e At time t4 after time t3, the detection voltage v d The detection voltage v at time t2 reaches a minimum value and then gradually increases. d and the detection voltage v at time t4 d The difference between the minimum value of the detection voltage v d The amplitude of V d The amplitude detection circuit 34B (FIG. 3B) detects the amplitude V d Detect.

[0028] Parasitic capacitance C c (Figure 4) shows the detection capacitance C det (Fig. 4) is sufficiently large, so the parasitic capacitance C c The point can be approximated as being short-circuited. Also, the parasitic capacitance C ab is the detection capacitance C det is sufficiently small compared to the parasitic capacitance C ab The part can be approximated as being in an open state. In addition, since the time constant of charging is sufficiently short compared to the time constant of discharging, the detection voltage v due to discharging during the period from time t1 to time t2 and the period from time t3 to time t4 is d Under these conditions, the change in the excitation voltage v e The amplitude of V e Detection voltage v d The amplitude of V d Ratio of V d / V e is expressed by the following formula:

number

[0029] Parasitic capacitance C ag can be considered to be a nearly fixed value, and the excitation voltage v e The amplitude of V e The detection capacitance C detWhen the voltage changes, the detection voltage v d The amplitude of V d Therefore, the detection voltage v d The amplitude of V d It is possible to detect the movement of the cheeks and lips from changes in this.

[0030] 6 is a flow chart for explaining the operation of the motion detection device 10 (FIG. 3A) according to the first embodiment. When the processing unit 40 (FIG. 3A) issues a trigger to the excitation circuit 35, the excitation voltage v e The excitation voltage v e The rise of the excitation voltage v at time t1 shown in Figure 5 e The processing unit 40 corresponds to the rising edge of the excitation voltage v e At time t2 (Figure 5) after a certain time has elapsed since the rise of the detection voltage v d The value (level) of the detected capacitance C is obtained during the period from time t1 to time t2 (step S2). det and parasitic capacitance C ag The time constant of the charge can be set based on the time constant of the charge.

[0031] Thereafter, when the processing unit 40 issues a trigger to the excitation circuit 35, the excitation voltage v e falls (step S3). The excitation voltage v e The falling edge of the excitation voltage v at time t3 shown in Figure 5 e The processing unit 40 detects the excitation voltage v e At time t4 (Figure 5) after a certain time has elapsed since the fall of the detection voltage v d The time from time t3 to time t4 should be set to the same as the time from time t1 to time t2.

[0032] Thereafter, the processing unit 40 calculates the detected voltage v d and the detected voltage v obtained in step S4 d The difference between the value of and is calculated (step S5). The procedure from step S1 to step S5 is repeated for the average value calculation time (step S6). The value of the average value calculation time is set in advance.

[0033] After the average value calculation time has elapsed, the difference calculated in step S5 is averaged (step S7). The processing unit 40 calculates this average value as the detection voltage v d The amplitude of V d and store it as amplitude V d The external device outputs information indicating the detected voltage v received from the motion detection device 10 to the external device (step S8). The procedure from step S1 to step S8 is repeated until the detection process is terminated (step S9). d The amplitude of V d Various operations are performed based on the time-varying waveform of the signal.

[0034] The averaging process in step S7 is not essential. If the averaging process is not performed, the repetitive process in step S6 is not performed, and the amplitude V d (Figure 5)

[0035] Next, referring to FIG. 7A, FIG. 7B, and FIG. 7C, the actually obtained detection voltage v d The amplitude of V d FIG. 7A shows the detected voltage v when the sounds "a", "i", "u", "e", and "o" are uttered in that order. d The amplitude of V d FIG. 7B is a graph showing the change over time in the detected voltage v d The amplitude of V d FIG. 7C is a graph showing the change over time in the detected voltage v d The amplitude of V d 7A and 7B, the period from the left end to the right end of the horizontal axis corresponds to about 10 seconds. In the graph of FIG. 7C, the period from the left end to the right end of the horizontal axis corresponds to about 3 seconds.

[0036] Waveforms a, b, c, and d in the graphs shown in FIGS. 7A, 7B, and 7C are the voltages v detected by the detection electrodes 31 facing the right cheek, the left cheek, the center of the lower lip, and the center of the upper lip, respectively. d The amplitude of V dIn the first embodiment, the detection electrode 31 is not disposed in a position facing the eyelid, but the opening and closing of the eyelid affects the facial muscles around the cheeks and lips, resulting in a detection voltage v d The amplitude of V d As shown in Figures 7A, 7B, and 7C, when the facial skin is moved, a characteristic waveform corresponding to the movement of the skin is obtained.

[0037] Next, the excellent effects of the first embodiment will be described. In the first embodiment, as shown in FIGS. 7A, 7B, and 7C, the detection voltage v d The amplitude of V d Therefore, the detection voltage v d The amplitude of V d From the waveform of the facial expression, the movement of the facial skin can be estimated. For example, by accumulating various evaluation data, it becomes possible to estimate the words spoken and the facial expressions. In addition, as shown in Figure 7C, it is also possible to detect the opening and closing of the eyelids.

[0038] Since the detection electrodes 31 do not directly touch the skin of the head, the motion detection device 10 does not interfere with the movement of the lips even when the motion detection device 10 is worn on the head 70. Furthermore, the structure 20 of the motion detection device 10 has a shape similar to that of a mask used daily. Therefore, the user does not feel any significant discomfort or strangeness even when wearing the motion detection device 10. In particular, the discomfort felt when moving the lips can be significantly reduced.

[0039] Next, the parasitic capacitance C between the detection electrode 31 and the excitation electrode 32 ab 4 and the arrangement of the ground electrode 33 will be described.

[0040] In the first embodiment, the excitation electrode 32 (FIG. 1) is in contact with the skin of the head 70, and the detection electrode 31 (FIGS. 1 and 2) faces the skin of the head 70 across a gap. The distance from the detection electrode 31 to the excitation electrode 32 is sufficiently longer than the distance from the detection electrode 31 to the skin of the head 70. For this reason, the capacitance (detection capacitance C det and parasitic capacitance C c The combined capacitance (FIG. 4) of the detection electrode 31 and the excitation electrode 32 is the parasitic capacitance C ab (Figure 4) is significantly larger.

[0041] Therefore, the parasitic capacitance C between the detection electrode 31 and the excitation electrode 32 in the device ab is negligible compared to the electrostatic capacitance through the head 70. Therefore, there is no need to electrostatically separate the detection electrode 31 and the excitation electrode 32 by disposing the ground electrode 33 between them. Note that, in order to stabilize the potential of the detection electrode 31 with respect to the ground potential, it is preferable to dispose the ground electrode 33 so that the detection electrode 31 and the ground electrode 33 are capacitively coupled to a certain degree.

[0042] In the first embodiment, the requirement that the detection electrode 31 and the ground electrode 33 be capacitively coupled is satisfied by arranging the detection electrode 31 and the ground electrode 33 so that they overlap when viewed from the surface of the head 70. It is not necessary to arrange the detection electrode 31 and the ground electrode 33 so that they overlap. For example, the ground electrode 33 may be arranged at a position shifted from the detection electrode 31 in the in-plane direction of the structure 20 (FIG. 1) when viewed from the surface of the head 70, and the two may be capacitively coupled.

[0043] Next, the parasitic capacitance C between the excitation electrode 32 and the ground electrode 33 bg The size of is explained.

[0044] As shown in equation (1), the parasitic capacitance C bg is the excitation voltage v e The amplitude of V e Detection voltage vd The amplitude of V d Ratio of V d / V e does not affect the parasitic capacitance C bg constitutes part of the load of the excitation circuit 35. bg If becomes too large, V d / V e In the first embodiment, the excitation electrode 32 and the ground electrode 33 are arranged so that they do not overlap when viewed from the surface of the head 70, and the distance from the ground electrode 33 to the excitation electrode 32 is sufficiently longer than the distance from the ground electrode 33 to the detection electrode 31. For this reason, the parasitic capacitance C bg becomes small enough, and V d / V e Therefore, an unnecessary increase in current that does not affect the measurement is suppressed.

[0045] Next, a motion detection device according to a modification of the first embodiment will be described. In the first embodiment, as shown in FIG. 5, the excitation voltage v applied to the excitation electrode 32 e In this embodiment, the impedance Z of the current path from the excitation electrode 32 through the head 70 to the detection electrode 31 is b is expressed by the following formula:

number

[0046] From the equivalent circuit diagram shown in Figure 4, the excitation voltage v e The amplitude of V e Detection voltage v d The amplitude of V d Ratio of V d / V e is expressed by the following formula:

number

[0047] Parasitic capacitance C c is the detection capacitance C det Much larger than bioresistance R b is 1 / ωC det If the requirement that θ is sufficiently smaller than θ is satisfied, then equation (3) is approximated by the following equation:

number

[0048] When the motion detection device 10 (FIG. 1) is attached to the head 70, the shortest distance from the ground electrode 33 to the excitation electrode 32 is sufficiently longer than the shortest distance from the ground electrode 33 to each of the detection electrodes 31. Therefore, the parasitic capacitance C ab is the detection capacitance C det Under this condition, equation (4) can be approximated as follows:

number

[0049] Equation (5) expresses the excitation voltage v e This is the same as equation (1) when the excitation voltage v e When the voltage is changed to a sine wave, the detection voltage v d The amplitude of V d It is possible to detect the movement of the cheeks and lips from changes in this.

[0050] [Second Example] Next, a motion detection device according to a second embodiment will be described with reference to Figures 8 and 9. Below, a description of the configuration common to the motion detection device according to the first embodiment described with reference to Figures 1 to 7C will be omitted.

[0051] 8 is a schematic perspective view of the structure 20 when the motion detection device according to the second embodiment is worn on the head. The structure 20 of the motion detection device according to the second embodiment is used as an inner mask worn between a mask 25 and the face. The structure 20 includes a lip facing portion 20D that faces the lips and the skin around them with a gap therebetween, cheek contact portions 20E provided at both ends of the lip facing portion 20D, an extension portion 20F that extends upward from the lip facing portion 20D, and a nose contact portion 20G that is provided at the tip of the extension portion 20F and comes into contact with the nose. The lip facing portion 20D is made of a mesh.

[0052] The structure 20 is pressed against the face by the mask 25, and the two cheek contacting portions 20E and one nose contacting portion 20G come into contact with the skin of the face, thereby supporting the lip facing portion 20D in front of the lips.

[0053] FIG. 9 is a plan view of the motion detection device 10 with the structure 20 unfolded in a plane. A cheek contact portion 20E is provided at each of the lateral ends of the lip facing portion 20D, an extension portion 20F extends vertically from the lateral center of the lip facing portion 20D, and a nose contact portion 20G is provided at the tip of the extension portion 20F. A plurality of detection electrodes 31 are attached to the lip facing portion 20D, and one detection electrode 31 is attached to the extension portion 20F. An excitation electrode 32 is attached to the nose contact portion 20G. In FIG. 9, the detection electrode 31 and the excitation electrode 32 are hatched. A ground electrode 33 is arranged on the lip facing portion 20D and the extension portion 20F so as to overlap with the detection electrode 31.

[0054] Next, the advantageous effects of the second embodiment will be described. The motion detection device 10 according to the second embodiment is attached to the inside of a mask that is used daily, so that the user feels little resistance. In addition, the mask that covers the motion detection device 10 can be replaced as needed, so that it is hygienic.

[0055] [Third Example] Next, a motion detection device according to a third embodiment will be described with reference to Fig. 10. Below, a description of the configuration common to the motion detection device according to the first embodiment described with reference to Figs. 1 to 7C will be omitted.

[0056] 10 is a perspective view of a motion detection device 10 according to a third embodiment. The motion detection device 10 according to the third embodiment has the form of a headset that is worn on the head when used. A pair of contact parts 20I are connected by a connecting part 20H. The pair of contact parts 20I contact the vicinity of the left and right ears of the head, respectively, and the connecting part 20H passes behind the head. The pair of contact parts 20I and the connecting part 20H form an ear hook part that is hung on the ears and supported by the head.

[0057] A boom arm 20J extends from one contact portion 20I toward the front of the lips. A lip facing portion 20K is attached to the tip of the boom arm 20J. When the motion detection device 10 is worn on the head, the lip facing portion 20K faces the lips with a gap between them. An excitation electrode 32 is attached to one contact portion 20I. When the motion detection device 10 is worn on the head, the excitation electrode 32 comes into contact with the skin around the ear.

[0058] A plurality of detection electrodes 31 and a ground electrode 33 are disposed on the lip facing portion 20K. The detection electrodes 31 face the lips or the skin surrounding the lips. The ground electrode 33 is disposed so as to overlap the detection electrodes 31.

[0059] Next, the excellent effects of the third embodiment will be described. The motion detection device 10 according to the third embodiment can be worn on the head in a similar manner to a commonly used headset microphone, allowing the user to use the motion detection device 10 without feeling any significant discomfort or oddness.

[0060] [Fourth Example] Next, a motion detection device according to a fourth embodiment will be described with reference to Fig. 11. Below, a description of the configuration common to the motion detection device according to the first embodiment described with reference to Figs. 1 to 7C will be omitted.

[0061] FIG. 11 is a perspective view of a motion detection device 10 according to the fourth embodiment. The motion detection device 10 according to the fourth embodiment has the form of a pair of glasses frames. A structure 20 includes a front portion 20L, a pair of temples 20M, and a pair of pads 20N. The structure 20 is worn on the head by hanging the pair of temples 20M on the left and right ears, respectively, and hanging the pads 20N on the nose. An excitation electrode 32 is disposed near the portion of the temple 20M that hangs on the ears. When the structure 20 is worn on the head, the excitation electrode 32 comes into contact with the skin of the head.

[0062] Two detection electrodes 31 are disposed on the front portion 20L in a portion facing the skin near the left and right eyelids. The detection electrodes 31 face the skin near the eyelids at a distance. A linear ground electrode 33 is disposed on the front portion 20L so as to overlap the two detection electrodes 31.

[0063] Next, the excellent effects of the fourth embodiment will be described. In the movement detection device 10 according to the first embodiment described with reference to Figures 1 to 7C, the detection electrode 31 faces the lips or the skin surrounding the lips. In contrast, in the movement detection device 10 according to the fourth embodiment, the detection electrode 31 faces the skin surrounding the eyelids. This allows the movement of the eyelids to be detected with high sensitivity.

[0064] Moreover, the motion detection device 10 according to the fourth embodiment can be worn in a similar manner to wearing eyeglasses, allowing the user to wear the motion detection device 10 without feeling any significant discomfort or oddness.

[0065] Next, a motion detection device 10 according to a modification of the fourth embodiment will be described. In the fourth embodiment, the structure 20 is in the form of a glasses frame, but it may also be in the form of swimming goggles or ski goggles.

[0066] The above-mentioned embodiments are merely examples, and it goes without saying that partial replacement or combination of the configurations shown in different embodiments is possible. Similar effects due to similar configurations of multiple embodiments are not mentioned in each embodiment. Furthermore, the present invention is not limited to the above-mentioned embodiments. For example, it will be obvious to those skilled in the art that various modifications, improvements, combinations, etc. are possible.

[0067] Based on the above examples described in this specification, the following invention is disclosed. <1> A structure to be attached to the head of a human body; A capacitance sensor mounted on the structure; Equipped with The capacitance sensor includes: A detection electrode facing the skin of the head on which the structure is attached, with a gap therebetween; a detection circuit that outputs a detection signal that changes in response to a change in capacitance between the detection electrode and the skin.

[0068] <2> The detection electrode faces at least one of the lips or the periphery of the lips and the eyelids or the periphery of the eyelids of the head to which the structure is attached. <1> The motion detection device according to claim 1 .

[0069] <3> Further, a wireless communication circuit is provided for wirelessly transmitting information corresponding to the detection signal to an external device. <1> or <2> The motion detection device according to claim 1 .

[0070] <4> The capacitance sensor further includes a ground electrode, an excitation electrode, and an excitation circuit that applies an AC voltage to the excitation electrode. The excitation electrode is in contact with the skin of the head on which the structure is worn, and the shortest distance from the ground electrode to the excitation electrode is longer than the shortest distance from the ground electrode to the detection electrode. <1> ~ <3> 13. A motion detection device according to claim 12, wherein

[0071] <5> A parasitic capacitance between the ground electrode and the excitation electrode is smaller than a parasitic capacitance between the ground electrode and the detection electrode. <4> The motion detection device according to claim 1 .

[0072] <6> When viewed from the skin of the head on which the structure is attached, the excitation electrode is disposed at a position not overlapping with the ground electrode. <4> or <5> The motion detection device according to claim 1 .

[0073] <7> The structure is a mask that covers the lips. <1> ~ <6> 13. A motion detection device according to claim 12, wherein

[0074] <8> The structure is disposed between a mask that is worn on the head and covers the lips and the skin of the head, and is supported by the head by being pressed against the head by the mask. <1> ~ <6> 13. A motion detection device according to claim 12, wherein

[0075] <9> The structure comprises: An ear hook portion that is hung on the ear and supported on the head; A boom arm extending from the ear hook to the front of the lips; Including, The detection electrode is supported on the boom arm at a portion in front of the lips. <1> ~ <6> 13. A motion detection device according to claim 12, wherein

[0076] <10> the structure has a shape of an eyeglass frame, The detection electrodes are attached to a front portion supported around the eyelids in front of the head. <1> ~ <6> 13. A motion detection device according to claim 12, wherein [Explanation of symbols]

[0077] 10. Motion detection device 20 Structures 20A Coverage 20B Mask string 20C Inner fabric 20D Lip opposing part 20E Cheek contact area 20F extension 20G nose contact part 20H connection part 20I contact part 20J Boom Arm 20K Lip opposing part 20L Front section 20M Vine 20N Pad 25 Mask 30 Capacitive Sensor 31 Detection electrode 32 Excitation electrode 33 Ground electrode 34 Detection circuit 34A Amplification circuit 34B Amplitude detection circuit 34C AD conversion circuit 35 Excitation circuit 40 Processing section 41 Wireless communication circuits 42 Battery 70 Human Head 71 Lips

Claims

1. A structure to be attached to the head of a human body; A capacitance sensor mounted on the structure; Equipped with The capacitance sensor includes: A detection electrode facing the skin of the head on which the structure is attached, with a gap therebetween; a detection circuit that outputs a detection signal that changes in response to a change in capacitance between the detection electrode and the skin.

2. 2. The movement detection device according to claim 1, wherein the detection electrode faces at least one of the lips or the area around the lips and the eyelids or the area around the eyelids of the head to which the structure is attached.

3. 3. The motion detection device according to claim 1, further comprising a wireless communication circuit for wirelessly transmitting information corresponding to the detection signal to an external device.

4. The capacitance sensor further includes a ground electrode, an excitation electrode, and an excitation circuit that applies an AC voltage to the excitation electrode.

3. The motion detection device of claim 1, wherein the excitation electrode is in contact with the skin of the head on which the structure is worn, and the shortest distance from the ground electrode to the excitation electrode is longer than the shortest distance from the ground electrode to the detection electrode.

5. 5. The motion detection device according to claim 4, wherein a parasitic capacitance between the ground electrode and the excitation electrode is smaller than a parasitic capacitance between the ground electrode and the detection electrode.

6. 5. The motion detection device according to claim 4, wherein the excitation electrode is disposed at a position not overlapping with the ground electrode when viewed from the skin of the head on which the structure is worn.

7. The motion detection device according to claim 1 or 2, wherein the structure is a mask for covering lips.

8. 3. The movement detection device according to claim 1, wherein the structure is disposed between a mask worn on the head to cover the lips and the skin of the head, and is supported on the head by being pressed against the head by the mask.

9. The structure comprises: An ear hook portion that is hung on the ear and supported on the head; A boom arm extending from the ear hook to the front of the lips; Including, 3. The motion detection device according to claim 1, wherein the detection electrode is supported on a portion of the boom arm in front of the lips.

10. the structure has a shape of an eyeglass frame, 3. The movement detection device according to claim 1, wherein the detection electrodes are attached to a front portion supported in front of the head around the eyelids.

Images