Sleeping position-controlling bed system

1. A sleeping-posture-control bed system comprising:

a bed floor including a back-lifting portion for lifting a user's back;

a bed-floor support body supporting the bed floor;

a back-lifting driver for lifting a head side of the back-lifting portion to tilt the back-lifting portion; and

a head detector,

wherein

the back-lifting portion includes a back-receiving surface and a head-receiving surface, each tiltable at different angles,

the head detector detects whether the user's head is located on the head-receiving surface or not,

the bed-floor support body includes a bed tilt driver for tilting the bed floor,

when the head detector detects that the user's head is located on the head-receiving surface, the back-lifting driver tilts the head-receiving surface and the back-receiving surface within a range of satisfying Mathematical Formula (1), and

when the head detector does not detect that the user's head is located on the head-receiving surface, the back-lifting driver does not tilt the head-receiving surface or the back-receiving surface,

the Mathematical Formula (1) being:

0°<θ x≦ 70°,−45°≦θ y< 0°, and −30°≦θ x+θy   (1)

where

θx is a tilt angle of the back-receiving surface when tilted, and the tilt angle of the back-receiving surface when the back-receiving surface is not tilted is set to be 0°, and

θy is a tilt angle of the head-receiving surface when an angle of an extended line of the back-receiving surface at the tilt angle θx is referred to as 0°,

a sleep monitor for monitoring sleep of the user sleeping on the bed floor;

a parasomnia detector for detecting a presence or absence of parasomnias on a basis of monitoring data of the sleep monitor; and

a back-lifting tilt controller for determining a value of θx and a value of θy on a basis of a detection result of the parasomnia detector and also determining a tilt direction and angle of the bed floor, the back-lifting tilt controller being for driving the back-lifting driver and the bed tilt driver so as to satisfy the value of θx and the value of θy and the tilt direction and angle of the bed floor.

2. The sleeping-posture-control bed system of claim 1 , further comprising a face direction detector for detecting whether the user's face is up, tilted to the right, tilted to the left, or down with respect to the head-receiving surface.

3. A sleeping-posture-control bed system comprising:

a bed floor including a back-lifting portion for lifting a user's back;

a bed-floor support body supporting the bed floor; and

a back-lifting driver for lifting a head side of the back-lifting portion to tilt the back-lifting portion,

wherein

the bed-floor support body includes a bed tilt driver for tilting the bed floor,

the back-lifting portion includes a back-receiving surface and a head-receiving surface, each tiltable at different angles; and

the back-lifting driver tilts the back-receiving surface and the head-receiving surface to prevent an increase in a pressure of blood flow into the user's head and to change the user's posture within a range of satisfying Mathematical Formula (2):

0°<θ x≦ 70°,−45°≦θ y< 0°, and −0°≦θ x+θy   (2)

where

θx is a tilt angle of the back-receiving surface when tilted, and the tilt angle of the back-receiving surface when the back-receiving surface is not tilted is set to be 0°, and

θy is a tilt angle of the head-receiving surface when an angle of an extended line of the back-receiving surface at the tilt angle θx is referred to as 0°,

a sleep monitor for monitoring sleep of the user sleeping on the bed floor;

a parasomnia detector for detecting a presence or absence of parasomnias on a basis of monitoring data of the sleep monitor; and

a back-lifting tilt controller for determining a value of θx and a value of θy on a basis of a detection result of the parasomnia detector and also determining a tilt direction and angle of the bed floor, the back-lifting tilt controller being for driving the back-lifting driver and the bed tilt driver so as to satisfy the value of θx and the value of θy and the tilt direction and angle of the bed floor.

4. The sleeping-posture-control bed system of claim 3 , further comprising a head detector for detecting whether the user's head is located on the head-receiving surface or not, wherein

when the head detector detects that the user's head is located on the head-receiving surface, the back-lifting driver tilts the head-receiving surface and the back-receiving surface within the range of satisfying Mathematical Formula (2), and

when the head detector does not detect that the user's head is located on the head-receiving surface, the back-lifting driver does not tilt the head-receiving surface or the back-receiving surface.

5. The sleeping-posture-control bed system of claim 3 , further comprising a face direction detector for detecting whether the user's face is up, tilted to the right, tilted to the left, or down with respect to the head-receiving surface.

6. A sleeping-posture-control bed system comprising:

a bed floor including a back-lifting portion for lifting a user's back;

a bed-floor support body supporting the bed floor; and

a back-lifting driver for lifting a head side of the back-lifting portion to tilt the back-lifting portion,

wherein

the bed-floor support body includes a bed tilt driver for tilting the bed floor,

the back-lifting portion includes a back-receiving surface and a head-receiving surface, each tiltable at different angles; and

the back-lifting driver tilts the back-receiving surface and the head-receiving surface to prevent an increase in a pressure of blood flow into the user's head and to change the user's posture within a range of satisfying Mathematical Formula (3):

2°≦θ x≦ 85°,−45°≦θ y≦− 2°, and −0°≦θ x+θy   (3)

where

θx is a tilt angle of the back-receiving surface when tilted, and the tilt angle of the back-receiving surface when the back-receiving surface is not tilted is set to be 0°, and

θy is a tilt angle of the head-receiving surface when an angle of an extended line of the back-receiving surface at the tilt angle θx is referred to as 0°,

a sleep monitor for monitoring sleep of the user sleeping on the bed floor;

a parasomnia detector for detecting a presence or absence of parasomnias on a basis of monitoring data of the sleep monitor; and

a back-lifting tilt controller for determining a value of θx and a value of θy on a basis of a detection result of the parasomnia detector and also determining a tilt direction and angle of the bed floor, the back-lifting tilt controller being for driving the back-lifting driver and the bed tilt driver so as to satisfy the value of θx and the value of θy and the tilt direction and angle of the bed floor.

7. The sleeping-posture-control bed system of claim 6 , further comprising a head detector for detecting whether the user's head is located on the head-receiving surface or not, wherein

when the head detector detects that the user's head is located on the head-receiving surface, the back-lifting driver tilts the head-receiving surface and the back-receiving surface within the range of satisfying Mathematical Formula (3), and

when the head detector does not detect that the user's head is located on the head-receiving surface, the back-lifting driver does not tilt the head-receiving surface or the back-receiving surface.

8. The sleeping-posture-control bed system of claim 6 , further comprising a face direction detector for detecting whether the user's face is up, tilted to the right, tilted to the left, or down with respect to the head-receiving surface.