Sleep induction system

Abstract

Provided is a sleep induction system capable of satisfactorily inducing a user to a sleep state. The sleep induction system includes: a main body on which at least a part of the body of a user can be placed; a stimulation unit that imparts biological stimulation to the user; and a control unit that causes the stimulation unit to execute a sleep induction operation for repeatedly imparting periodic biological stimulation to the user. The control unit causes the stimulation unit to start the sleep induction operation when a first time has elapsed since at least the part of the body of the user was placed on the main body.

Description

Sleep induction system

[0001] The following disclosure relates to a sleep induction system. This application claims priority based on Japanese Patent Application No. 2024-199672 filed in Japan on November 15, 2024, and incorporates its content herein by reference.

[0002] For example, Patent Document 1 discloses a method of improving the quality of the sleep state using a respiration synchronization induction device that induces synchronization of the respiratory cycle.

[0003] Japanese Patent Application Laid-Open No. 2020-81314

[0004] The respiration synchronization induction device described in Patent Document 1 has a housing entirely covered by a cushion part and a expansion and contraction mechanism that expands and contracts the housing, and the controller adjusts the cycle and depth of expansion and contraction. When the user uses this device at bedtime, it is necessary to operate the device before sleep. Therefore, there are concerns such as the user feeling inconvenient to operate and being unable to obtain the sleep induction effect, or the operation leading to arousal and preventing falling asleep.

[0005] An aspect of the present disclosure aims to provide a sleep induction system capable of favorably inducing a user into a sleep state. <9000012> A sleep induction system according to an aspect of the present disclosure includes a main body on which at least a part of the user's body can be placed, a stimulation application unit that applies a biological stimulus to the user, and a control unit that causes the stimulation application unit to execute a sleep induction operation for repeatedly applying the periodic biological stimulus to the user. The control unit starts the sleep induction operation in the stimulation application unit when a first period of time has elapsed since at least a part of the user's body was placed on the main body.

[0007] According to an aspect of the present disclosure, a sleep induction system capable of favorably inducing a user into a sleep state can be provided. [[ID=!3]]

[0008] This is a block diagram showing the configuration of the main part of the sleep induction system 1 according to Embodiment 1. This is a schematic diagram of the area around the head of a user lying on their side with their head resting on the main body 2 so that the back of their head is in contact with the main body 2, as viewed from the Z1 side in the sleep induction system 1 of Embodiment 1. This is a diagram conceptually showing the positional relationship between the tactile stimulation unit 41 and the user's head H as viewed from direction a in Figure 2. This is a diagram conceptually showing the positional relationship between the tactile stimulation unit 41 and the user's head H as viewed from direction b in Figure 2. This is a diagram conceptually showing the positional relationship between the tactile stimulation unit 41 provided inside the main body 2 and the piping etc. 44 connected to the outside of the main body 2. This is a diagram conceptually showing the positional relationship between the tactile stimulation unit 41 provided inside the main body 2 and the control unit 5 provided on the main body 2. This is a flowchart showing an example of control by the control unit 5 in the sleep induction system 1 according to Embodiment 1, etc. This is a chart conceptually showing the timing of the switching of the operation of the stimulation unit 4 in the sleep induction system 1 according to Embodiment 1. This is a schematic diagram of the area around the head of a user lying on their side with their head resting on the main body 2 so that the back of their head is in contact with the main body 2, as viewed from the Z1 side in the sleep induction system 1 of Embodiment 2. This is a diagram conceptually showing the positional relationship between the tactile stimulation unit 41 and the user's head H as viewed from direction a in Figure 9. This is a diagram conceptually showing the positional relationship between the tactile stimulation unit 41 and the user's head H as viewed from direction b in Figure 9. This is a block diagram showing the configuration of the main part of the sleep induction system 1 according to Embodiment 3. This is a block diagram showing the configuration of the main part of the sleep induction system 1 according to Embodiment 4. This is a flowchart showing an example of control by the control unit 5 in the sleep induction system 1 according to Embodiment 4. This is a block diagram showing the configuration of the main part of the sleep induction system 1 according to Embodiment 5. This is a flowchart showing an example of control by the control unit 5 in the sleep induction system 1 according to Embodiment 5.

[0009] The embodiments of the sleep induction system 1 described herein will be explained below with reference to the drawings. This disclosure is not limited to the embodiments described below, and design modifications can be made as appropriate within the scope of satisfying the configuration of this disclosure. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant explanations are omitted. Only the main parts are shown in the drawings. The following explanation will focus on the main parts and the parts related to this disclosure.

[0010] In this specification, the surface of the main body 2 on which at least a part of the user's body is placed is referred to as the main surface 2a of the main body 2. Of the directions perpendicular to this main surface 2a (also referred to as the height direction Z), the side on which the user's body is placed is designated as Z1, and the opposite side as Z2. Of the directions parallel to the main surface 2a, when the user is lying on their side with at least a part of their body placed on the main surface 2a, the side towards the top of the head (also referred to as the height direction Y) is designated as Y2, and the side towards the legs is designated as Y1. Of the directions perpendicular to the height direction Z and the height direction Y (also referred to as the shoulder width direction X in the main body 2 on which the user's head can be placed), the left side when viewed from the Z1 side is designated as X1, and the right side as X2.

[0011] (Embodiment 1) Figure 1 is a block diagram showing the configuration of the main parts of the sleep induction system 1 according to this embodiment. The main body 2 is omitted in Figure 1, but at least a part of the stimulation application unit 4 is provided on the main body 2. Figure 2 is a schematic diagram of the area around the head of a user who is lying on their side with their head resting on the main body 2 so that the back of their head is in contact with the main body 2, as viewed from the Z1 side. Figure 3 is a diagram conceptually showing the positional relationship between the tactile stimulation application unit 41 and the user's head H as viewed from direction a in Figure 2. Figure 4 is a diagram conceptually showing the positional relationship between the tactile stimulation application unit 41 and the user's head H as viewed from direction b in Figure 2.

[0012] The sleep induction system 1 according to this embodiment comprises a main body 2, sensors 3, a stimulation unit 4, a control unit 5, and a power supply unit 6. At least a portion of the stimulation unit 4 is located inside the main body 2, but other parts may be located outside the main body 2. Components located inside the main body 2 may be separable from the main body 2.

[0013] (Main body 2) Main body 2 is capable of supporting (positioning) at least a part of the user's body. In this embodiment, at least a part of the user's body is the user's head. Main body 2 is preferably a pillow or cushion.

[0014] The main surface 2a of the main body 2 is, for example, a rectangle when viewed from the Z1 side. In Figure 2, the main surface 2a of the main body 2 is formed in a rectangular shape having a pair of long sides and a pair of short sides when viewed from the Z1 side. The shape of the main surface 2a of the main body 2 may be triangular, a rounded rectangle, an ellipse, a trapezoid, a rhombus, a semicircle, a semiellipse, or a shape that is an arbitrary combination of various figures. Furthermore, the main surface 2a of the main body 2 may be parallel to the surface on which the main body 2 is placed (for example, a horizontal plane), may have a recess that is concave on the Z2 side, or may be deformable to become concave on the Z2 side by pressing from the Z1 side. The main body 2 may also be composed of multiple members integrated together, or may be composed of multiple members that are detachably connected to each other.

[0015] The material (also referred to as the base material) of the main body 2 may be any material commonly used in bedding, such as urethane, synthetic resins such as polyester; natural fibers such as cotton; latex; buckwheat hulls; etc. The main body 2 may also have a cover made of cloth or the like on the outside.

[0016] An example of the main body 2 is one having a material part formed from the above material and a cover part that houses the material part. In such a main body 2, it is preferable that a tactile stimulation part 41, which will be described later, is arranged in the space between the material part and the cover part. The tactile stimulation part 41 may be arranged so as to be separable from the material part and the cover part, and the cover part may be provided with an opening that allows the tactile stimulation part 41 to be removed.

[0017] (Sensors 3) Sensors 3 are devices capable of detecting changes in the user's position relative to the main surface 2a of the main body 2. Changes in the user's position relative to the main surface 2a include, for example, changes in the user's posture on the main surface 2a or changes in the user's state. Specific examples of sensors 3 include at least one sensor selected from the group consisting of pressure sensors and gyro sensors, a camera capable of capturing images of the user's posture, and a device (e.g., a wearable device) capable of detecting the user's heart rate, blood pressure, or respiratory rate in real time. The sleep induction system 1 preferably includes at least one sensor selected from the group consisting of pressure sensors and gyro sensors.

[0018] The pressure sensor and gyro sensor are preferably placed inside the main body 2, and are also preferably placed near the centroid of the main surface 2a of the main body 2 in order to improve detection accuracy.

[0019] The pressure sensor detects pressure changes on the main surface 2a of the main body 2 and outputs the detection result to the placement determination unit 51 of the control unit 5. For example, if the amount of pressure change detected by the pressure sensor exceeds a predetermined value, the placement determination unit 51 determines that at least a part of the user's body is placed on the main surface 2a of the main body 2. The pressure sensor can continuously detect pressure changes.

[0020] The gyro sensor detects changes in the angle of the main surface 2a of the main body 2 (i.e., changes in the orientation of an object on the main surface 2a) and outputs the detection result to the placement determination unit 51 of the control unit 5. For example, if the angle change detected by the gyro sensor falls within a predetermined range, the placement determination unit 51 determines that at least a part of the user's body is placed on the main surface 2a of the main body 2. The gyro sensor can detect angle changes continuously or intermittently.

[0021] The camera and the device are located outside the main body 2. For example, if the sleep induction system 1 has the camera, the placement determination unit 51 calculates the amount of user movement over a predetermined period of time based on the image captured by the camera, and determines that at least a part of the user's body is placed on the main surface 2a of the main body 2 if the calculated amount of movement falls within a predetermined range. Also, if the sleep induction system 1 has the device, the placement determination unit 51 determines that at least a part of the user's body is placed on the main surface 2a of the main body 2 based on the user's heart rate, blood pressure, or respiratory rate detected by the device.

[0022] (Stimulation-providing unit 4) The stimulation-providing unit 4 can provide biological stimulation to the user. The biological stimulation is at least one selected from the group consisting of, for example, tactile stimulation by contact with the user and auditory stimulation by outputting sound to the user.

[0023] The stimulation unit 4, upon receiving instructions from the control unit 5 (described later), performs a sleep induction operation that repeatedly applies periodic biological stimuli to the user. More specifically, the stimulation unit 4 is capable of performing a first action, which applies a first biological stimulus to the user, and a second action, which is different from the first action. By repeatedly performing the first and second actions, the stimulation unit 4 applies periodic biological stimuli to the user. Examples of combinations of the first and second actions include, for example, a combination of applying and stopping the biological stimulus (ON / OFF), or a combination of applying the first biological stimulus and applying other biological stimuli.

[0024] The sleep induction cycle consists of a first action and a second action performed after the first action. Considering the ease with which the user can fall asleep, it is preferable that the sleep induction cycle includes multiple cycles of varying durations. In particular, it is more preferable that the sleep induction cycle includes a first cycle and a second cycle that is located after the first cycle and has a longer duration than the first cycle, and it is especially preferable that it includes a third cycle that is located after the second cycle and has a longer duration than the second cycle. By gradually increasing the duration of the cycles in this way, the sleep induction system 1 can induce the user into a sleep state more comfortably and easily.

[0025] Preferably, the stimulation unit 4 has a tactile stimulation unit 41 that provides tactile stimulation to the user as biological stimulation by raising and lowering the main surface 2a of the main body 2 on which at least a part of the user's body (in this embodiment, the user's head) is placed. The following describes the case in which the stimulation unit 4 has a tactile stimulation unit 41.

[0026] The tactile stimulation unit 41 raises and lowers the main surface 2a of the main body 2 on which at least a part of the user's body is placed. Specifically in this embodiment, the tactile stimulation unit 41 is an air bag 41 that can be inflated and deflated. For example, the stimulation unit 4 has an air bag 41 as the tactile stimulation unit 41, a pump 42 that supplies air to the air bag 41, and an openable and closable solenoid valve 43. The solenoid valve 43 is connected to the air bag 41 via an air storage container (not shown) and piping such as tubes and hoses. Power is supplied to the stimulation unit 4 from the power supply unit 6.

[0027] The tactile stimulation unit 41 is provided on the main body 2. More specifically, the tactile stimulation unit 41 is provided inside the main surface 2a. Although all the components constituting the stimulation unit 4 may be provided on the main body 2, considering the ease with which the user can fall asleep, it is preferable that the tactile stimulation unit 41 is located inside the main body 2, and other components (for example, a pump 42 or solenoid valve 43 that may generate sound or vibration) are located outside the main body 2.

[0028] The tactile stimulation portion 41 is preferably located on the edge of the main surface 2a of the main body 2 when viewed from the side facing the main surface 2a (i.e., viewed from the Z1 side). The edge of the main surface 2a means the part that is closer to the outer edge (periphery) of the main surface 2a than to the centroid (center) of the main surface 2a when viewed from the Z1 side, and can also be described as the end side of the main surface 2a. For example, if the main surface 2a of the main body 2 is rectangular when viewed from the Z1 side, the edge of the main surface 2a is the part that is closer to the outer edge than to the center of the rectangle.

[0029] If the main surface 2a of the main body 2 is longitudinal in the first direction, it is preferable that the tactile stimulation unit 41 be located on one of the ends in a direction perpendicular to the first direction, as viewed from the Z1 side. It is assumed that when a user is sleeping normally, they rest their head on the central side of the main surface 2a rather than on the ends. Therefore, as shown in Figure 2, if the main surface 2a of the main body 2 is longitudinal in the shoulder width direction X, it is presumed that in the height direction Y perpendicular to the shoulder width direction X, the load on the central part of the main surface 2a when the user's head is placed on the main surface 2a is greater than on the ends on the Y1 and Y2 sides of the main surface 2a. Therefore, if the tactile stimulation unit 41 is positioned on the end side, avoiding the area with the greatest load in the height direction Y (for example, the area indicated by arrow c in Figure 4) (see Figure 4), the influence of the tactile stimulation unit 41 on the user's sleeping posture itself is reduced, and awakening is more effectively prevented.

[0030] Furthermore, if the main surface 2a of the main body 2 is longitudinal in the first direction (shoulder width direction X in Figure 2), it is preferable that the tactile stimulation application unit 41 be located towards the center of the main surface 2a in the first direction when viewed from the Z1 side (see Figures 2 and 3). When the tactile stimulation application unit 41 is in this position, it can efficiently provide tactile stimulation to the user.

[0031] Figure 2 illustrates an example in which the main surface 2a of the main body 2 is longitudinal in the shoulder width direction X. The tactile stimulation portion 41 is located, when viewed from the Z1 side, at the Y1 end in the height direction Y which is perpendicular to the shoulder width direction X, and is also located on the central side of the main surface 2a in the shoulder width direction X.

[0032] As described above, when the tactile stimulation unit 41 is located inside the main body 2 and the pump 42 and solenoid valve 43 etc. are located outside the main body 2, it is preferable that the piping and power cord etc. (reference numeral 44) connected to the pump 42 etc. be inserted into the main body 2 from the end of the main surface 2a of the main body 2 opposite to the side where the tactile stimulation unit 41 is located, when viewed from the Z1 side, and connected to the tactile stimulation unit 41. This reduces the influence of the piping etc. 44 on a user who, for example, turns over in bed.

[0033] If the main surface 2a of the main body 2 is longitudinal in the shoulder width direction X, it is preferable that the piping and power cord etc. 44 are inserted into the interior of the main body 2 from the central part of the main surface 2a in the shoulder width direction X, at the end on the Y2 side opposite to the Y1 side where the tactile stimulation unit 41 is located in the height direction Y perpendicular to the shoulder width direction X, and connected to the tactile stimulation unit 41 (see Figure 5). Figure 5 is a conceptual diagram showing the positional relationship between the tactile stimulation unit 41 provided inside the main body 2 and the piping etc. 44 connected to the outside of the main body 2. Figure 5 is a view from the Z1 side.

[0034] The operation of the stimulation unit 4 is controlled by the control unit 5, which will be described later. When the pump 42 is driven with the solenoid valve 43 closed, the tactile stimulation unit (i.e., air bladder) 41 located inside the main body 2 inflates. When the air bladder 41 inflates, the main surface 2a of the main body 2 rises. Subsequently, when the pump 42 stops and the solenoid valve 43 opens, the air bladder 41 deflates. The deflation of the air bladder 41 can be achieved by natural exhaust when the solenoid valve 43 is opened. When the inflated air bladder 41 deflates, the main surface 2a of the main body 2 sinks. Therefore, the tactile stimulation unit 41 is capable of performing a rise-initiating operation, which is the first operation, to raise the main surface 2a of the main body 2, and a sinking operation, which is the second operation, to sink the main surface 2a of the main body 2. The sleep induction cycle consists of a rise-initiating operation and a sinking operation, which is performed following the rise-initiating operation.

[0035] The sleep induction operation may include multiple cycles in which at least one of the duration and intensity of the biological stimulation applied to the user differs from one another. The number of repetitions of each cycle, i.e., the number of times a set consisting of one uplift action and one sinking action is repeated, is not particularly limited.

[0036] As described above, the sleep induction operation preferably includes multiple cycles of varying durations. Specifically, the sleep induction operation preferably includes a first cycle, a second cycle located after the first cycle and in which at least one of the uplift operation and the sinking operation is longer than that of the first cycle, and it is particularly preferable to further include a third cycle located after the second cycle and in which at least one of the uplift operation and the sinking operation is longer than that of the second cycle. In particular, if the durations of the sinking operation in the first, second, and third cycles are F1, F2, and F3, respectively, it is preferable that F1, F2, and F3 satisfy the relationship F1 < F2 < F3. After the third cycle, the uplift operation and the sinking operation may be repeated while changing the duration of at least one of the uplift operation and the sinking operation.

[0037] It is known that when a person goes to sleep, their heart rate and blood pressure decrease as they enter a sleep state, and therefore their respiratory rate also decreases. Accordingly, as the duration of the uplift and sinking movements increases in stages, the rhythm of the tactile stimulation provided to the user by the uplift and sinking of the main surface 2a of the main body 2 becomes more easily synchronized with the breathing of the user as they enter a sleep state. Thus, the sleep induction system 1 becomes even easier to guide the user into a sleep state.

[0038] As an example of sleep induction operation, the uplift and downlift movements are repeated multiple times with R1 = 3 seconds and F1 = 3 seconds, then the uplift and downlift movements are repeated multiple times with R2 = 3 seconds and F2 = 5 seconds, and finally the uplift and downlift movements are repeated multiple times with R3 = 3 seconds and F3 = 7 seconds. R1, R2, and R3 are the durations of the uplift movements in the first, second, and third cycles, respectively.

[0039] The sleep induction operation may also include multiple cycles in which the intensity of the biostimulation applied to the user differs from that of the other. For example, the sleep induction operation may include a first cycle and a second cycle located after the first cycle, in which the intensity of at least one of the uplift and sinking movements is greater than that of the first cycle, or a third cycle located after the second cycle, in which the intensity of at least one of the uplift and sinking movements is greater than that of the second cycle. After the third cycle, the uplift and sinking movements may be repeated while the intensity of at least one of the uplift and sinking movements is changed. The intensity of the uplift and sinking movements can be changed, for example, by adjusting the discharge rate of the pump 42.

[0040] When a person falls asleep, shallow breathing occurs during the initial stages of sleep, but breathing becomes deeper thereafter. Therefore, if the intensity of the uplift or sinking motion is changed in stages as described above, the intensity (degree) of the tactile stimulation given to the user by the uplift and sinking of the main surface 2a of the main body 2 will more easily synchronize with the depth of breathing of the user as they enter a sleep state. Thus, the sleep induction system 1 becomes even easier to guide the user into a sleep state.

[0041] (Control Unit 5) The control unit 5 is responsible for causing the stimulation unit 4 to perform a sleep induction operation that repeatedly applies periodic biological stimuli to the user. If the stimulation unit 4 has the tactile stimulation unit 41 described above, the control unit 5 causes the tactile stimulation unit 41 to repeatedly raise and lower the main surface 2a of the main body 2 as part of the sleep induction operation. The part of the control unit 5 that controls the operation of the stimulation unit 4 in particular is sometimes referred to as the operation instruction unit 50.

[0042] The control unit 5 has a placement determination unit 51 that determines, based on signals output by the sensors 3, whether at least a part of the user's body is placed on the main surface 2a of the main unit 2. The operation instruction unit 50 of the control unit 5 outputs an operation instruction to the stimulation application unit 4 based on the determination result from the placement determination unit 51. Details of the control will be described later.

[0043] The control unit 5 also has a time storage unit that stores the elapsed time since at least a part of the user's body was placed on the main surface 2a of the main body 2. This elapsed time may be the count number of an internal clock, or may be a time based on the absolute time (i.e., the actual time) acquired from a clock unit (not shown).

[0044] The control unit 5 is constituted by, for example, a CPU or the like, and may be a microcomputer. The control unit 5 transmits and receives various signals directly to / from other units or via a communication unit that the sleep induction system 1 may further include. The communication unit (not shown) is connected to a communication line via a router, a gateway, etc., and one-way or two-way communication with an external terminal may be possible via the communication line, or one-way or two-way communication with the external terminal may be possible directly, for example, by short-range wireless communication such as Bluetooth (registered trademark) without using the communication line.

[0045] The control unit 5 may be provided on the main body 2, or may be provided outside the main body 2. When the control unit 5 is provided on the main body 2, the control unit 5 may be provided inside the main body 2, or may be provided on the main surface 2a of the main body 2, the surface opposite to the main surface 2a, or a side surface.

[0046] When the control unit 5 is provided on the main body 2, the control unit 5 is preferably arranged at a position away from the tactile stimulation applying unit 41 in consideration of the ease of the user's falling asleep and operability, etc. For example, when the main surface 2a of the main body 2 has a longitudinal shape in the shoulder width direction X, the control unit 5 is at the end side on the Y2 side opposite to the Y1 side where the tactile stimulation applying unit 41 is arranged in the body length direction Y orthogonal to the shoulder width direction X, and is preferably located at the end side (X1 side or X2 side) in the shoulder width direction X of the main surface 2a (see FIG. 6). FIG. 6 is a diagram conceptually showing the positional relationship between the tactile stimulation applying unit 41 provided inside the main body 2 and the control unit 5 provided on the main body 2. FIG. 6 is a view seen from the Z1 side.

[0047] When the control unit 5 is provided outside the main body 2, the tactile stimulation applying unit 41 and the control unit 5 located outside the main body 2 are connected by wire or wirelessly. When the tactile stimulation applying unit 41 and the control unit 5 are connected via a wire (for example, a cord), the cord is inserted into the main body 2 from the end on the side opposite to the side where the tactile stimulation applying unit 41 is located on the main surface 2a of the main body 2 as viewed from the Z1 side, similar to the above-described piping 44 etc., and is preferably connected to the tactile stimulation applying unit 41 (see FIG. 5). Thereby, for example, the influence of the cord on a user who turns over is reduced.

[0048] (Power supply unit 6) The power supply unit 6 supplies power to the stimulation applying unit 4, the control unit 5, etc. The power supply unit 6 may be provided in the main body 2 or may be provided outside the main body 2. The power supply unit 6 that can be arranged in the main body 2 may have, for example, a battery and a power supply circuit etc., or may have a rechargeable battery and a power receiving terminal (for example, a USB connector etc.) that can be electrically connected to an external charging power supply terminal. The position where the power supply unit 6 is arranged is preferably arranged at a site away from the tactile stimulation applying unit 41 in consideration of the ease of the user's going to bed and operability etc., similar to the above-described control unit 5 (see also FIG. 6). Also, the power supply unit 6 that can be arranged outside the main body 2 has a power cord 44 for connecting the stimulation applying unit 4 to a commercial power supply (see also FIG. 5).

[0049] (Control and sleep induction operation) Next, referring to FIGS. 7 and 8 etc., the timing etc. for controlling the stimulation applying unit 4 by the control unit 5 will be described. FIG. 7 is a flowchart showing an example of the control by the control unit 5 in the sleep induction system 1 according to the present embodiment. FIG. 8 is a chart diagram conceptually showing the timing etc. at which the operation of the stimulation applying unit 4 switches in the sleep induction system 1 according to the present embodiment. In FIG. 8, the vertical axis represents time. The main body 2 is a pillow or a cushion.

[0050] When a user lies down with their head resting on the main surface 2a of the main unit 2, the placement determination unit 51 receives signals from the sensors 3 and determines that the user's head is resting on the main surface 2a of the main unit 2 (step S1). The time at which the placement determination unit 51 makes this determination, that is, the time when the user's head is resting on the main surface 2a of the main unit 2, is defined as time T0 (see Figure 8). After a predetermined time (referred to as the first time T1) has elapsed since the user's head was resting on the main surface 2a of the main unit 2 (step S2), the control unit 5 instructs the stimulation unit 4 to start sleep induction operation, and the stimulation unit 4, upon receiving instructions from the control unit 5, starts sleep induction operation (step S3). As a result, sleep induction operation is performed (step S4). The first time T1 is, for example, 2 to 10 seconds.

[0051] Here, if the sleep induction system 1 has a pressure sensor as part of the sensors 3, the control unit 5 determines that a first time T1 has elapsed since the user's head was placed on the main unit 2 if the pressure sensor continues to detect a pressure change exceeding a predetermined value from time T0 until a first time T1 has elapsed, or if the sleep induction system 1 has a gyro sensor, the control unit 5 determines that a first time T1 has elapsed since the user's head was placed on the main unit 2 if the amount of movement between time T0 and the first time T1 has elapsed, based on the image captured by the camera. If the sleep induction system 1 has the above-mentioned camera, the control unit 5 determines that a first time T1 has elapsed since the user's head was placed on the main unit 2 if the amount of movement between time T0 and the first time T1 has elapsed falls within a predetermined range. If the sleep induction system 1 has the above-mentioned device, the control unit 5 determines that a first time T1 has elapsed since the user's head was placed on the main unit 2 if the user's heart rate, etc., at the time the first time T1 has elapsed falls within a predetermined range. When the control unit 5 makes this determination, it instructs the stimulation unit 4 to start sleep induction operation (step S3).

[0052] The control unit 5 also instructs the stimulation unit 4 to stop the sleep induction operation when the termination condition is met. In this embodiment, the termination condition is when a predetermined time (referred to as the second time T2) has elapsed from the start of the sleep induction operation. Specifically, during the execution of the sleep induction operation (step S4), when the second time T2 has elapsed from the start of the sleep induction operation in step S3 (step S5), the control unit 5 instructs the stimulation unit 4 to stop the sleep induction operation (step S6). The second time T2 is, for example, 5 to 30 minutes. Since it is preferable that the timing of stopping this sleep induction operation is during the user's sleep period (the period after Tx in Figure 8), the second time T2 is set appropriately according to the user and general sleep patterns, etc.

[0053] When the control unit 5 satisfies the above termination conditions and stops the sleep induction operation (step S6), it does not allow the stimulation unit 4 to start the sleep induction operation until a predetermined time (referred to as the third time T3) has elapsed from the time the sleep induction operation was stopped. On the other hand, once the third time T3 has elapsed from the time the control unit 5 stopped the sleep induction operation (step S7), the control flow returns to step S1. That is, after the third time T3 has elapsed from the time the sleep induction operation was stopped, the control unit 5, once the first time T1 has elapsed since the user's head was placed on the main surface 2a of the main body 2 again (steps S1 to S2), causes the stimulation unit 4 to start the sleep induction operation again (step S3). In such a sleep induction system 1, after the user wakes up, the sleep induction operation is automatically started when the user goes to sleep again without having to operate the device. The third time T3 is preferably, for example, 5 hours or more. Furthermore, the third time period T3 is preferably less than 24 hours, and more preferably shorter than the time obtained by subtracting the first time period T1 from 24 hours (i.e., satisfying the relationship "T3 < (24 - T1)").

[0054] As shown in Figure 8, the period from when the user places their head on the main surface 2a of the main unit 2 before going to sleep until they fall asleep, that is, the period from time T0 to time Tx, is called the sleep induction period. Falling asleep means entering a sleep state. The period during which the user is in a sleep state, that is, the period from time Tx onward, is called the sleep period. The sleep induction system 1 of this embodiment is suitable for use during the sleep induction period.

[0055] (Embodiment 2) The sleep induction system 1 of this embodiment is equipped with a plurality of tactile stimulation units 41 (i.e., specifically air bladders). Except for this point, the sleep induction system 1 of this embodiment has the same configuration as the sleep induction system 1 of Embodiment 1. The following describes the differences from Embodiment 1, and the same matters as in Embodiment 1 will be omitted as appropriate.

[0056] Figure 9 is a schematic diagram of the area around the head of a user lying on their side with their head resting on the main body 2 so that the back of their head is in contact with the main body 2, as viewed from the Z1 side in the sleep induction system 1 of this embodiment. Figure 10 is a conceptual diagram showing the positional relationship between the tactile stimulation unit 41 and the user's head H as viewed from direction a in Figure 9. Figure 11 is a conceptual diagram showing the positional relationship between the tactile stimulation unit 41 and the user's head H as viewed from direction b in Figure 9.

[0057] When the main surface 2a of the main body 2 is longitudinal in the first direction (shoulder width direction X in Figure 9), it is preferable that at least two of the multiple tactile stimulation units 41 are located towards the center of the main surface 2a in the first direction when viewed from the Z1 side (see Figures 9 and 10). When the tactile stimulation units 41 are in this position, they can efficiently provide tactile stimulation to the user.

[0058] Furthermore, at least two of the multiple tactile stimulation units 41 are arranged spaced apart from each other along the edge of the main surface 2a of the main body 2 when viewed from the side facing the main surface 2a. In other words, at least two of the tactile stimulation units 41 are arranged parallel to the edge (i.e., end) of the main surface 2a and spaced apart from each other when viewed from the Z1 side. In this case, it is preferable that the tactile stimulation units 41 are arranged such that the area where the load is greatest in the shoulder width direction X when the user's head is placed on the main surface 2a does not overlap with at least two of the tactile stimulation units 41 when viewed from the Z1 side.

[0059] As shown in Figure 9, if the main surface 2a of the main body 2 is longitudinal in the shoulder width direction X, it is presumed that the load on the main surface 2a when the user's head is placed on it is greater towards the center of the main surface 2a than towards the X1 and X2 ends of the main surface 2a in the shoulder width direction X. Therefore, if the tactile stimulation unit 41 is positioned to avoid the area with the greatest load in the shoulder width direction X (for example, the area indicated by arrow c in Figure 10) (see Figure 10), the influence of the tactile stimulation unit 41 on the user's sleeping posture itself is further reduced, and awakening is more effectively prevented.

[0060] If the main surface 2a of the main body 2 is longitudinal in the first direction, it is preferable that at least two tactile stimulation units 41 be located at one of the ends in a direction perpendicular to the first direction, as viewed from the Z1 side. As shown in Figure 9, if the main surface 2a of the main body 2 is longitudinal in the shoulder width direction X, it is presumed that in the height direction Y perpendicular to the shoulder width direction X, the load on the central part of the main surface 2a when the user's head is placed on the main surface 2a is greater than that on the Y1 and Y2 ends of the main surface 2a. Therefore, if the tactile stimulation units 41 are positioned to avoid the area with the greatest load in the height direction Y (for example, the area indicated by arrow c in Figure 11) (see Figure 11), the influence of the tactile stimulation units 41 on the user's sleeping posture itself is further reduced, and awakening is more effectively prevented.

[0061] (Embodiment 3) In the sleep induction system 1 of this embodiment, the control unit 5 estimates the user's respiratory state and controls the operation of the stimulation unit 4 so that the duration of the sleep induction cycle is synchronized with the estimated respiratory state. Except for this point, the sleep induction system 1 of this embodiment has substantially the same configuration as the sleep induction system 1 of Embodiment 1 or 2. The following describes matters that differ from Embodiment 1 or 2, and the description of matters that are the same as in Embodiment 1 or 2 will be omitted as appropriate.

[0062] Figure 12 is a block diagram showing the configuration of the main parts of the sleep induction system 1 according to this embodiment. Although the main body 2 is omitted in Figure 12, at least a part of the stimulation application unit 4 is provided on the main body 2.

[0063] The sleep induction system 1 has a device (i.e., sensors 3) capable of detecting changes in the user's position relative to the main surface 2a of the main body 2, and the control unit 5 has a breathing estimation unit 52 that estimates the user's breathing state based on signals acquired from the sensors 3. The sensors 3 that output signals to the breathing estimation unit 52 may also be the sensors 3 that output signals to the placement determination unit 51 described above. For example, based on the amount of pressure change or angle change acquired from a pressure sensor or gyro sensor as one of the sensors 3, the breathing estimation unit 52 can estimate the user's breathing rate and breathing depth per predetermined time. The breathing estimation unit 52 can also estimate the user's breathing rate and breathing depth per predetermined time based on the amount of movement based on the image taken by the camera or the user's heart rate acquired from the device.

[0064] The operation instruction unit 50 of the control unit 5 controls the operation of the stimulation unit 4 so that the duration of the sleep induction operation cycle is synchronized with the estimated respiratory state. For example, if the respiratory estimation unit 52 estimates that the user is repeating breathing with an inspiratory period of Ti and an exhalation period of Te, the operation instruction unit 50 controls the driving of the pump 42 and the opening and closing of the solenoid valve 43 so that, for example, the rise period R and the sinking period F of the main surface 2a of the main body 2 become Ti and Te, respectively.

[0065] The operation instruction unit 50 also preferably controls the operation of the stimulation application unit 4 so that the intensity of the periodic biological stimulation applied to the user by the stimulation application unit 4 is synchronized with the estimated respiratory state. For example, if the respiratory estimation unit 52 estimates that the user's breathing is shallow, the operation instruction unit 50 adjusts the discharge amount of the pump 42 so that the degree of rise and fall of the main surface 2a of the main body 2 increases, for example, to encourage the user to take deep breaths. Conversely, if the respiratory estimation unit 52 estimates that the user's breathing is deep, the operation instruction unit 50 adjusts the discharge amount of the pump 42 so that the degree of rise and fall of the main surface 2a of the main body 2 decreases, for example.

[0066] The respiratory estimation unit 52 preferably estimates the user's respiratory state continuously or intermittently. If the estimated respiratory state changes, the operation instruction unit 50 preferably changes the duration of the sleep induction operation cycle or the intensity of the biological stimulation applied to the user in accordance with the change.

[0067] The sleep induction system 1 preferably further comprises a memory unit (not shown) that stores the estimated respiratory state. The control unit 5 preferably determines the period of the cycle immediately following the start of sleep induction operation and the intensity of the biological stimulation based on the estimated respiratory state stored in the memory unit, and instructs the stimulation unit 4 to start sleep induction operation for the determined period and intensity. Such a sleep induction system 1 is even more convenient and easy to use because it automatically starts sleep induction operation suitable for the user based on the respiratory state during the previous or previous sleep, without the user having to perform detailed device operations.

[0068] (Embodiment 4) In the sleep induction system 1 of this embodiment, the control unit 5 stops the sleep induction operation of the stimulation unit 4 when the termination condition is met. In this embodiment, the termination condition is when a second time T2 has elapsed from the start of the sleep induction operation, or when it is determined that the user is in a sleep state. Except for this point, the sleep induction system 1 of this embodiment has substantially the same configuration as the sleep induction system 1 of Embodiments 1, 2, or 3. The following describes matters that differ from Embodiments 1, 2, or 3, and the description of matters that are the same as Embodiments 1, 2, or 3 will be omitted as appropriate.

[0069] Figure 13 is a block diagram showing the configuration of the main parts of the sleep induction system 1 according to this embodiment. Although the main body 2 is omitted in Figure 13, at least a part of the stimulation application unit 4 is provided on the main body 2.

[0070] The control unit 5 has a sleep determination unit 53 that determines whether or not the user is in a sleep state based on the breathing state estimated by the breathing estimation unit 52. As described above, when a person goes to sleep, the number of breaths decreases when they enter a sleep state. Therefore, if the number of breaths per predetermined time falls below a predetermined value in the breathing state estimated by the breathing estimation unit 52, the sleep determination unit 53 can determine that the user is in a sleep state. Also, since breathing deepens when a person enters a sleep state, the sleep determination unit 53 may determine that the user is in a sleep state if the depth of breathing falls within a predetermined range in the breathing state estimated by the breathing estimation unit 52.

[0071] The sleep determination unit 53 may perform the above determination after a predetermined period has elapsed since the start of sleep induction operation, or it may continue to perform the above determination while sleep induction operation is being carried out.

[0072] Referring to Figure 14, the timing of the control unit 5's control of the stimulation unit 4 will be explained, but aside from the matters described below, it is substantially the same as the matters described in Embodiment 1 (see also Figures 7 and 8). Figure 14 is a flowchart showing an example of control by the control unit 5 in the sleep induction system 1 according to this embodiment.

[0073] The control unit 5 instructs the stimulation unit 4 to stop the sleep induction operation when the termination condition is met. As described above, in this embodiment, the termination condition is when a second time T2 has elapsed from the start of the sleep induction operation, or when it is determined that the user is in a sleep state. Specifically, for example, during the sleep induction operation (step S4), the sleep determination unit 53 continuously or intermittently determines whether the user is in a sleep state or not (step S8). In step S8, if the sleep determination unit 53 determines that the user is in a sleep state (Yes), no further sleep induction is needed, so the control unit 5 instructs the stimulation unit 4 to stop the sleep induction operation (step S6). On the other hand, if the sleep determination unit 53 does not determine that the user is in a sleep state (No), the control unit 5 does not allow the stimulation unit 4 to stop the sleep induction operation and continues to operate it, and when a second time T2 has elapsed from the start of the sleep induction operation in step S3 (step S5), the control unit 5 instructs the stimulation unit 4 to stop the sleep induction operation (step S6).

[0074] In this embodiment as well, as described in Embodiment 1, when the control unit 5 satisfies the termination conditions and stops the sleep induction operation (step S6), the stimulation unit 4 is not allowed to start the sleep induction operation until a third time T3 has elapsed from the time the sleep induction operation was stopped. When the third time T3 has elapsed from the time the control unit 5 stopped the sleep induction operation (step S7), the control flow returns to step S1.

[0075] The sleep induction system 1 of this embodiment is superior in terms of convenience and ease of use because it can automatically continue and stop sleep induction operation according to the user's sleep state without requiring user operation of the device.

[0076] (Modification 1) In the sleep induction system 1 of Embodiment 4, the sleep determination unit 53 may determine that the user is in a sleep state based on an image taken by a camera capable of capturing the user's posture.

[0077] (Embodiment 5) The sleep induction system 1 of this embodiment further includes at least one of a start switch unit 71 that initiates sleep induction operation when operated by the user, and a stop switch unit 72 that stops sleep induction operation when operated by the user. Except for this point, the sleep induction system 1 of this embodiment has substantially the same configuration as the sleep induction system 1 of Embodiments 1, 2, 3, or 4. In the following, matters that differ from Embodiments 1, 2, 3, or 4 will be described, and matters that are the same as Embodiments 1, 2, 3, or 4 will be omitted from the description as appropriate. At least one of the start switch unit 71 and the stop switch unit 72 will be referred to as the switch unit 7.

[0078] Figure 15 is a block diagram showing the configuration of the main parts of the sleep induction system 1 according to this embodiment. Although the main body 2 is omitted in Figure 15, at least a part of the stimulation application unit 4 is provided on the main body 2.

[0079] The start switch unit 71 is a unit that starts sleep induction operation when operated by the user, and the stop switch unit 72 is a unit that stops sleep induction operation when operated by the user, and both transmit a signal to the control unit 5 based on the user's operation. For example, the start switch unit 71 may also serve as the stop switch unit 72, and an example of such a switch unit is one that switches the power supply path to the stimulation unit 4 between an on state and an off state. The switch unit 7 has, for example, a push button operated by the user and a physical switch (for example, a tact switch) that is linked to the movement of the push button. When the user presses the push button, the power supply path to the stimulation unit 4 is turned on via the physical switch, driving the pump 42, etc., or the power supply path is turned off, stopping the driving of the pump 42, etc.

[0080] As described above, in embodiments 1 to 4, the control unit 5 does not allow the stimulation unit 4 to start the sleep induction operation until a third time T3 has elapsed from the time the sleep induction operation is stopped in step S6. In contrast, in the sleep induction system 1 of this embodiment, which includes a start switch unit 71, it is preferable that the control unit 5 can start the sleep induction operation even during the period from the time the sleep induction operation is stopped until the third time T3 has elapsed, if the start switch unit 71 issues an instruction to start the sleep induction operation.

[0081] As described above, in embodiments 1 to 4, the control unit 5 instructs the stimulation unit 4 to stop the sleep induction operation when the termination conditions are met. In contrast, in the sleep induction system 1 of this embodiment, which includes a stop switch unit 72, the control unit 5 instructs the stimulation unit 4 to stop the sleep induction operation not only when the termination conditions are met, but also when it receives an instruction from the stop switch unit 72. If the stop of the sleep induction operation is due to an instruction from the stop switch unit 72, it is preferable that the control unit 5 restarts the sleep induction operation in the stimulation unit 4 when the first time T1 has elapsed since at least a part of the user's body was placed on the main unit 2, even if the third time T3 has elapsed since the time the sleep induction operation was stopped.

[0082] Next, with reference to Figure 16 and the like, the timing of the control unit 5 controlling the stimulation unit 4 will be explained, but aside from the matters described below, it is substantially the same as the matters described in Embodiments 1 to 4 (see also Figures 7, 8 and 14). Figure 16 is a flowchart showing an example of control by the control unit 5 in the sleep induction system 1 according to this embodiment. As an example, Figure 16 shows a flowchart in which this embodiment is applied to the sleep induction system 1 of Embodiment 4 described above, and the sleep induction system 1 is equipped with a start switch unit 71 and a stop switch unit 72.

[0083] The control unit 5 stops the sleep induction operation in the stimulation unit 4 when a second time T2 has elapsed since the start of the sleep induction operation (step S5), when it determines that the user is in a sleep state (step S8), or when it receives an instruction from the stop switch unit 72 (not shown) (step S6). An example of when an instruction is received from the stop switch unit 72 is when the user manually operates the start switch unit 71, thereby turning on the power supply path to the stimulation unit 4 (manual on). Even if the sleep induction operation has been stopped and a third time T3 has elapsed, the control unit 5 can start the sleep induction operation if it receives an instruction from the start switch unit 71 to start the sleep induction operation (if the answer is Yes in step S9).

[0084] Figure 15 shows that if the answer to step S9 is Yes, the control flow returns to (proceeds to) step S1. However, the control flow may also skip steps S1 and S2 and proceed to step S3. In other words, if the answer to step S9 is Yes, the control unit 5 may initiate sleep induction operation on the stimulation unit 4 without performing placement determination on the placement determination unit 51 (step S3).

[0085] If no instruction to start the sleep induction operation is given from the start switch unit 71 during the period from the time the sleep induction operation is stopped until the third time T3 has elapsed (the answer is No in step S9), the control unit 5 determines whether the reason for stopping the sleep induction operation in step S6 was an instruction from the stop switch unit 72 (step S10). An example of a case where an instruction is received from the stop switch unit 72 is when the user manually operates the stop switch unit 72, thereby turning off the power supply path to the stimulation unit 4 (manual off). If the stop of the sleep induction operation is due to an instruction from the stop switch unit 72 (the answer is Yes in step S10), the control unit 5 can start the sleep induction operation even if it is within the period from the time the sleep induction operation was stopped until the third time T3 has elapsed. On the other hand, if in step S10 the stop of the sleep induction operation is not due to an instruction from the stop switch unit 72 (the answer is No), the control unit 5 returns to step S6.

[0086] Figure 15 shows that if the answer to step S10 is Yes, the control flow returns to (proceeds to) step S1. However, the control flow may skip steps S1 and S2 and proceed to step S3. In other words, if the answer to step S10 is Yes, the control unit 5 may initiate sleep induction operation on the stimulation unit 4 without performing placement determination on the placement determination unit 51 (step S3).

[0087] The user may operate the start switch unit 71 at any time, and the control unit 5 may, upon receiving instructions from the start switch unit 71, start a new sleep induction operation on the stimulation unit 4 from that point. Similarly, the user may operate the stop switch unit 72 at any time, and the control unit 5 may, upon receiving instructions from the stop switch unit 72, stop the sleep induction operation on the stimulation unit 4 at that point.

[0088] The sleep induction system 1 of this embodiment not only automatically starts and stops sleep induction operation, but also allows the user to start and stop sleep induction operation, thus offering superior convenience and ease of use.

[0089] (Modification 2) In the sleep induction system 1 of Embodiments 1 to 5, the control unit 5 may, as sleep induction operation, provide a stop period between the rise and sinking of the main surface 2a of the main body 2, during which the rise and sinking of the main surface 2a of the main body 2 are stopped. In this case, the tactile stimulation unit 41 is capable of performing a rise-start operation to raise the main surface 2a of the main body 2, stopping the rise, sinking operation to sink the main surface 2a of the main body 2, and stopping the sinking, and the sleep induction operation cycle consists of a rise-start operation, stopping the rise, sinking operation performed after the stop, and stopping the sinking.

[0090] When the pump 42 is driven with the solenoid valve closed, the air bag 41 inflates, causing the main surface 2a of the main body 2 to bulge. However, when the pump 42 stops with the solenoid valve 43 closed, the inflation of the air bag 41 stops, and therefore the bulging of the main surface 2a of the main body 2 stops. Also, when the solenoid valve 43 is opened with the pump 42 stopped, the air bag 41 contracts, causing the main surface 2a of the main body 2 to sink. However, when the solenoid valve 43 is closed with the pump 42 stopped, the contraction of the air bag 41 stops, and therefore the sinking of the main surface 2a of the main body 2 stops. In this way, the control unit 5 may control the driving of the pump 42 and the opening and closing of the solenoid valve 43 so that the above-mentioned stop periods are provided in the sleep induction operation. Each stop period is not particularly limited and can be, for example, 1 second to 10 seconds.

[0091] Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above and can be implemented in various forms without departing from its essence. Furthermore, the multiple components disclosed in the above embodiments can be modified as appropriate. For example, some components from all the components shown in one embodiment may be added to the components of another embodiment, or some components from all the components shown in one embodiment may be removed from the embodiment.

[0092] Furthermore, the drawings schematically show each component in order to facilitate understanding of the invention, and the thickness, length, number, spacing, etc. of each component shown may differ from the actual dimensions due to the convenience of drawing creation. Also, the configuration of each component shown in the above embodiments is merely an example and is not particularly limiting, and it goes without saying that various modifications are possible within the scope that does not substantially deviate from the effects of this disclosure.

Claims

1. A sleep induction system comprising: a main body on which at least a part of a user's body can be placed; a stimulation unit that provides biological stimulation to the user; and a control unit that causes the stimulation unit to perform a sleep induction operation that repeatedly provides the user with periodic biological stimulation, wherein the control unit causes the stimulation unit to start the sleep induction operation when a first time has elapsed since at least a part of the user's body has been placed on the main body.

2. The sleep induction system according to claim 1, wherein the stimulation unit has a tactile stimulation unit that provides tactile stimulation to the user as biological stimulation by raising and lowering the main surface of the main body on which at least a part of the user's body is placed, and the control unit causes the tactile stimulation unit to repeatedly raise and lower the main surface as a sleep induction operation.

3. The sleep induction system according to claim 2, wherein, when viewed from the opposite side of the main surface, the tactile stimulation-providing portion is located on the edge side of the main surface.

4. The sleep induction system according to claim 3, comprising a plurality of tactile stimulation units, wherein at least two of the plurality of tactile stimulation units are arranged spaced apart from each other along the edge.

5. The sleep induction system according to claim 4, wherein the main surface has a longitudinal shape in the first direction, and the two tactile stimulation-providing parts are located on the central side of the main surface in the first direction.

6. The sleep induction system according to claim 1, wherein the stimulation unit is capable of performing a first action of applying the first biological stimulus to the user and a second action different from the first action, the cycle of the sleep induction operation consists of the first action and the second action performed after the first action, and the sleep induction operation includes a plurality of cycles having different durations.

7. The sleep induction system according to claim 6, wherein the sleep induction operation includes a first cycle and a second cycle that is located after the first cycle and has a longer duration than the first cycle.

8. The sleep induction system according to claim 7, wherein the sleep induction operation further comprises a third cycle that is located after the second cycle and has a longer duration than the second cycle.

9. The sleep induction system according to claim 2, wherein the control unit provides a rest period between the rise and sinking of the main surface during the sleep induction operation, during which the rise and sinking of the main surface are stopped.

10. The sleep induction system according to claim 6, wherein the control unit estimates the user's respiratory state and controls the operation of the stimulation unit so that the duration of the sleep induction operation cycle is synchronized with the estimated respiratory state.

11. The sleep induction system according to claim 10, wherein the control unit controls the operation of the stimulation unit so that the intensity of the periodic biological stimulation that the stimulation unit provides to the user is synchronized with the estimated respiratory state.

12. The sleep induction system according to claim 10, further comprising a memory unit for storing the estimated respiratory state.

13. The sleep induction system according to claim 12, wherein the control unit determines the period of the cycle immediately after the start of the sleep induction operation and the intensity of the biological stimulation based on the estimated respiratory state stored in the memory unit, and causes the stimulation unit to start the sleep induction operation with the determined period and intensity.

14. The sleep induction system according to any one of claims 1 to 13, wherein the control unit stops the sleep induction operation when a termination condition is met, and the termination condition is when a second time has elapsed from the start of the sleep induction operation, or when it is determined that the user is in a sleep state.

15. The sleep induction system according to claim 14, wherein, when the control unit stops the sleep induction operation after the termination condition is met, the stimulation unit does not start the sleep induction operation until a third time has elapsed from the time the sleep induction operation is stopped.

16. The sleep induction system according to claim 15, further comprising a start switch unit which is operated by the user to start the sleep induction operation, wherein even if a third time has elapsed from the time the sleep induction operation has been stopped, the control unit will be able to start the sleep induction operation if an instruction to start the sleep induction operation is given from the start switch unit.

17. The sleep induction system according to claim 15, further comprising a stop switch unit which is operated by the user to stop the sleep induction operation, wherein if the stopping of the sleep induction operation is due to an instruction from the stop switch unit, the control unit will restart the sleep induction operation on the stimulation unit when the first time has elapsed since at least a part of the user's body has been placed on the main unit, even if a third time has elapsed since the time the sleep induction operation was stopped.

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