JP2012050531A - Mattress - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mattress capable of dispersing the body pressure of a person lying on bed by setting the internal pressure of a cell low.SOLUTION: A mattress 1 includes: a cell unit 2 having a plurality of cells 20; a body pressure adjusting part 3 which changes the internal pressure of the cells 20; a sensor 5 which is arranged in a vertical direction of the cell unit 2 and which is capable of detecting the body pressure applied on a plurality of detection parts A0101 to A1616; and a control part 4 controlling the body pressure adjusting part 3 based on the detected value of the sensor 5. When the internal pressure of the cell 20 reaches the bottom-out condition B3, the maximum value of the body pressure distribution passes in a time order the descending sections E1 to E3 where a first-grade time differential value of the maximum value is negative, and the rising sections E4 to E6 where a first-grade time differential value is positive. The control part 4 switches to an internal pressure setting mode F1 to set the internal pressure of the cell 20 in the internal pressure setting section between the starting point of the descending section E1 and the starting point of the rising section E4.

Description

  The present invention relates to a mattress including a plurality of cells containing a fluid such as gas or liquid.

  In hospitals and nursing homes, bed slipping of bedridden persons sleeping on mattresses, such as patients and bedridden elderly people, has become a problem. Therefore, a mattress in which a large number of air cells are arranged is commercially available in order to suppress bed slip.

  FIG. 11 shows a cross-sectional view in the front-rear direction of a bed on which a conventional mattress is arranged. As shown in FIG. 11, the bed 100 includes a mattress 101 and a bed main body 110. The mattress 101 includes a cell unit 102. The cell unit 102 includes a large number of air cells 102a. Due to the body pressure of the bedridden m, a part of the cell unit 102 (for example, a portion corresponding to the head, shoulder, buttock, and buttock) sinks downward.

  In order to suppress bed slipping, the bedridden m may be turned over. In view of this point, Patent Document 1 discloses a floor slip prevention device having a load sensor sheet. A large number of pressure sensitive elements are arranged on the load sensor sheet. According to the bed slip prevention device described in the document, the internal pressure of the air bag is adjusted based on the detected value of the pressure sensitive element. And the bedridden m is forced to turn over.

JP 2000-189472 A

  Moreover, what is necessary is just to disperse the body pressure of the bedridden m in order to suppress bed slip. In order to disperse the body pressure of the bedridden m, it is preferable that the internal pressures of the plurality of air cells 102a are low. However, if the internal pressure of the air cell 102a is excessively lowered, the air cell 102a may be in a “bottomed state”. Here, the bottomed state refers to a state where the air cell 102a is completely crushed.

  That is, when the internal pressure of the air cell 102a is reduced or when the body pressure is concentrated on the air cell 102a having a low internal pressure, the air cell 102a may be completely crushed. In this case, the cushioning property of the air cell 102a is not exhibited. For this reason, the bedridden m is in a state as if sleeping directly on the hard bed body 110. Therefore, in the bottomed state, a floor slip particularly easily occurs. The mattress of the present invention has been completed in view of the above problems. An object of this invention is to provide the mattress which can disperse the body pressure of a bedridden person by setting the internal pressure of a cell low.

  (1) In order to solve the above-described problem, the mattress of the present invention supports the bedridden person from below and includes a cell unit having a plurality of cells through which fluid can enter and exit, and the bed pressure by changing the internal pressure of the cell. A body pressure adjusting unit that changes the body pressure distribution of the person, and a sensor thin film that is disposed on at least one of the upper and lower sides of the cell unit and includes a polymer and can be elastically deformed by the body pressure of the bedridden person A plurality of electrodes that are directly or indirectly connected to the sensor thin film, and a plurality of detection units formed between the plurality of electrodes, and the body pressure applied to the plurality of detection units is an electric quantity A mattress comprising: a sheet-like sensor that can be detected as: a control unit that controls the body pressure adjustment unit based on the amount of electricity of the sensor and changes the internal pressure of the cell. It reaches the bottoming state that is completely crushed In this case, the maximum value of the body pressure distribution is obtained when the internal pressure of the cell is reduced and the first time differential value of the maximum value is negative, and the bottomed state An ascending section in which the first-order time differential value of the maximum value is positive, and the control unit performs a descending section starting point at which the descending section is started and an ascending section starting point at which the ascending section is started. In the internal pressure setting section between the first and second sensors, the body pressure adjusting unit is controlled based on the amount of electricity of the sensor to switch to an internal pressure setting mode for setting the internal pressure of the cell.

  Here, “directly or indirectly” means that the electrode is directly connected to the sensor thin film regardless of whether the electrode and the sensor thin film are bonded or not, and at least one between the electrode and the sensor thin film. Including another layer (for example, an electrode protection layer).

  In the process of reaching the bottoming state where the internal pressure of the cell is reduced and the cell is completely crushed, the maximum value of the body pressure distribution changes in a time-series characteristic locus. That is, the maximum value of the body pressure distribution includes a descending section in which the first-order time differential value is negative, and an ascending section in which the first-order time derivative value is positive (in the rising section, the cell is bottomed) , Pass in time order.

  According to the mattress of the present invention, the internal pressure of the cell can be set low by paying attention to the characteristic change of the maximum value of the body pressure distribution. For this reason, the body pressure of the bedridden person can be dispersed.

  The sensor thin film can be elastically deformed by the body pressure of the bedridden person. For this reason, the sensor is flexible and has elasticity. Therefore, the sensor is easily deformed along the body of the bedridden person. Therefore, even when the sensor is disposed near the bedridden person, for example, above the cell unit, the bedridden person does not easily feel a sense of incongruity such as hardness and stiffness. Further, the sensor easily deforms following the movement of the bedridden body. For this reason, the detection accuracy of the body pressure distribution is high.

  (2) Preferably, in the configuration of (1), the control unit is configured to adjust the body pressure adjusting unit based on the electric quantity of the sensor after the maximum value of the body pressure distribution passes through the internal pressure setting section. It is better to switch to the bottomed suppression mode that increases the internal pressure of the cell. According to this structure, a control part switches to bottoming suppression mode after passing an internal pressure setting area. In the bottoming suppression mode, it is possible to suppress the cells from being held in the bottomed state.

  (3) Preferably, in the configuration of (1) or (2), a descending section inflection point at which the second-order time differential value of the maximum value shifts from negative to positive is set in the descending section, and the control The part is preferably configured to switch to the internal pressure setting mode after passing through the descending section inflection point.

  Here, “the second-order time differential value shifts from negative to positive” includes the case where the second-order time differential value shifts from approximately 0 to positive and the second-order time differential value shifts from negative to approximately 0. . According to this configuration, the internal pressure of the cell can be set lower.

  (4) Preferably, in the configuration of (3), in the internal pressure setting section, the first-order time differential value of the maximum value is changed from negative to 0, and the second-order time differential value of the maximum value is changed from positive to 0. In addition, it is preferable that a constant pressure section start point to be transferred is set, and the control unit switches to the internal pressure setting mode after passing through the constant pressure section start point. According to this configuration, the internal pressure of the cell can be set lower.

  (5) Preferably, in the configuration according to any one of (1) to (4), in the sensor, the plurality of electrodes include a strip-shaped upper electrode disposed on the upper side of the sensor thin film, and the sensor thin film. A plurality of the detection units formed by intersecting the upper electrode and the lower electrode when viewed from above or below, and the body. It is better to adopt a configuration in which the capacitance of the detection unit is changed by the pressure. According to this configuration, the body pressure distribution can be calculated based on the change in the capacitance of the detection unit.

  (6) Preferably, in the configuration of the above (5), the upper electrode and the lower electrode are preferably formed to include a polymer and a conductive filler filled in the polymer. .

  According to this configuration, the upper electrode and the lower electrode can expand and contract together with the sensor thin film. Therefore, there is little possibility that the upper and lower electrodes regulate the expansion and contraction of the sensor thin film. Moreover, the stretchability of the whole sensor becomes larger. For this reason, the sensor is likely to be deformed along the body of the bedridden person. In addition, the sensor easily deforms following the movement of the bedridden body.

(7) Preferably, in the configuration according to any one of (1) to (6), the plurality of cells are divided into a plurality of groups, and the body pressure adjustment unit includes a plurality of the cells in the group unit. By changing the internal pressure, the body pressure distribution of the bedridden person is changed, and the cell unit and the sensor are arranged so that at least one cell overlaps the sensor for each group when viewed from above or below. The coordinates of the plurality of cells arranged and the coordinates of the plurality of detection units of the sensor are preferably not associated with each other.
The cell unit and the sensor are arranged so that at least one cell overlaps the sensor for each group when viewed from above or below. As an example, when there are three groups, three types of cells (at least three cells) are arranged so as to overlap the sensor corresponding to the number of groups.

  According to the mattress of the present invention, the control unit calculates the appropriate internal pressure based on the maximum value of the body pressure distribution. For this reason, even if the coordinates of the cell (horizontal position) and the coordinates of the detector (horizontal position) are not related by the controller, the internal pressure of the cell is adjusted based on the amount of electricity from the detector. can do. Therefore, the position of the sensor can be freely moved with respect to the cell unit. For example, the sensor can be arranged at a site where body pressure tends to concentrate, such as the head or buttocks of a bedridden person. Moreover, the mattress of this invention can be obtained only by adding a sensor to an existing cell unit. For this reason, versatility is high.

  According to the mattress of the present invention, the body pressure of the bedridden person can be dispersed by setting the internal pressure of the cell low.

It is a disassembled perspective view of the bed in which the mattress of the first embodiment is arranged. It is a longitudinal direction sectional view of the bed. It is a top view of the cell unit of the same mattress. It is a permeation | transmission top view of the sensor of the same mattress. It is VV sectional drawing of FIG. FIG. 6 is a correspondence diagram of air cell states, air cell internal pressure, body pressure distribution maximum value, first-order time differential value, and second-order time differential value. It is a correspondence diagram of the state of an air cell, the internal pressure of an air cell, the maximum value of body pressure distribution, the first-order time differential value, and the second-order time differential value of the mattress of a second embodiment. It is a correspondence diagram of the state of an air cell, the internal pressure of an air cell, the maximum value of body pressure distribution, the first-order time differential value, and the second-order time differential value of the mattress of a third embodiment. It is sectional drawing of the sensor of the mattress of 4th embodiment. It is a top view of the sensor of the mattress of the fifth embodiment. It is sectional drawing of the front-back direction of the bed by which the conventional mattress is arrange | positioned.

  Hereinafter, embodiments of the mattress of the present invention will be described.

<First embodiment>
[Mattress arrangement and configuration]
First, the arrangement and configuration of the mattress of this embodiment will be described. FIG. 1 shows an exploded perspective view of a bed on which the mattress of this embodiment is arranged. FIG. 2 shows a cross-sectional view of the bed in the front-rear direction. As shown in FIGS. 1 and 2, the bed 9 includes a mattress 1, a bed main body 90, and a cushion mat 91.

  The mattress 1 is disposed on the upper surface of the floor plate 900 of the bed main body 90. The cushion mat 91 is disposed on the upper surface of the mattress 1. The cushion mat 91 is made of a three-dimensional knitted fabric such as polyethylene terephthalate (“Fusion (registered trademark)” manufactured by Asahi Kasei Fibers Co., Ltd.) and has a rectangular plate shape. The bedridden M is sleeping on the upper surface of the cushion mat 91. The mattress 1 includes a cell unit 2, a body pressure adjustment unit, a control unit, a sensor 5, and a cover 6.

(Cell unit 2, cover 6)
FIG. 3 shows a top view of the cell unit of the mattress of this embodiment. As shown in FIGS. 1-3, the cell unit 2 is exhibiting the rectangular plate shape long in the front-back direction. The cell unit 2 includes a total of 24 air cells 20. The air cell 20 is included in the concept of the “cell” of the present invention. Each of the air cells 20 is made of a urethane film and has a rectangular tube shape that is long in the left-right direction. The air cell 20 is continuous in the front-rear direction. The air cell 20 is flexible. Air is supplied and discharged between the air cell 20 and a body pressure adjusting unit described later. Air is included in the “fluid” concept of the present invention. The cover 6 is made of a urethane film and has a rectangular bag shape that is long in the front-rear direction. The cover 6 houses the cell unit 2.

(Body pressure adjusting unit 3)
The body pressure adjustment unit 3 includes a total of 24 supply / discharge units 30. The 24 sets of supply / discharge units 30 are connected to 24 air cells 20. In FIG. 3, only one set of the supply / discharge unit 30 is shown.

  Each of the 24 sets of supply / discharge units 30 includes a pump 300, a supply / discharge switching valve 301, a pressure gauge 302, a main hose 305, and an exhaust hose 306. The main hose 305 connects the pump 300 and the air cell 20. In the middle of the main hose 305, a supply / discharge switching valve 301 and a pressure gauge 302 are arranged. The supply / discharge switching valve 301 is disposed on the pump 300 side, and the pressure gauge 302 is disposed on the air cell 20 side. The exhaust hose 306 is connected to the supply / discharge switching valve 301. By switching the supply / discharge switching valve 301, the main hose 305 and the exhaust hose 306 can be connected and disconnected.

(Sensor 5)
As shown in FIGS. 1 and 2, the sensor 5 is disposed on the upper surface of the cover 6. FIG. 4 is a transparent top view of the mattress sensor of the present embodiment. FIG. 5 shows a VV cross-sectional view of FIG. In FIG. 4, the upper insulating coating layer 52 is omitted. Further, the lower electrodes 01Y to 16Y and the lower wirings 01y to 16y are indicated by thin lines. Further, the detection portions A0101 to A1616 are hatched. In FIG. 5, the upper wirings 01x to 16x, the lower wirings 01y to 16y, the upper wiring connector 54, and the lower wiring connector 55 are omitted.

  As shown in FIGS. 4 and 5, the sensor 5 includes a sensor thin film 51, upper electrodes 01X to 16X, lower electrodes 01Y to 16Y, detection units A0101 to A1616, upper wirings 01x to 16x, and a lower side. Wirings 01y to 16y, an upper insulating coating layer 52, a lower insulating coating layer 53, an upper wiring connector 54, and a lower wiring connector 55 are provided. It should be noted that the upper two digits “◯◯” in the detection unit code “AOOΔΔ” correspond to the upper electrodes 01X to 16X. The lower two digits “ΔΔ” correspond to the lower electrodes 01Y to 16Y. The elongation at break of the sensor 5 is 300%.

  The sensor thin film 51 is made of urethane rubber and has a sheet shape. Urethane rubber is included in the concept of “polymer” of the present invention. The sensor thin film 51 has a rectangular film shape that is long in the front-rear direction.

  A total of 16 upper electrodes 01X to 16X are arranged on the upper surface of the sensor thin film 51. The upper electrodes 01X to 16X are each formed to include acrylic rubber and conductive carbon black. Acrylic rubber is included in the “polymer” concept of the present invention. Conductive carbon black is included in the concept of “conductive filler” of the present invention. Each of the upper electrodes 01X to 16X has a strip shape. The upper electrodes 01X to 16X each extend in the left-right direction. The upper electrodes 01X to 16X are arranged in the front-rear direction so as to be substantially parallel to each other with a predetermined interval.

  A total of 16 upper wirings 01x to 16x are arranged on the upper surface of the sensor thin film 51. The upper wirings 01x to 16x are each formed to include acrylic rubber and silver powder. The upper wirings 01x to 16x each have a linear shape. The upper wiring connector 54 is disposed at the right front corner of the sensor thin film 51. The upper wirings 01x to 16x connect the right ends of the upper electrodes 01X to 16X and the upper wiring connector 54, respectively.

  The upper insulating coating layer 52 is disposed above the sensor thin film 51. The upper insulating coating layer 52 is formed including acrylic rubber. The upper insulating coating layer 52 has a sheet shape. The upper insulating coating layer 52 covers the sensor thin film 51, the upper electrodes 01X to 16X, and the upper wirings 01x to 16x from above.

  A total of 16 lower electrodes 01Y to 16Y are arranged on the lower surface of the sensor thin film 51. Each of the lower electrodes 01Y to 16Y is formed to include acrylic rubber and conductive carbon black. Acrylic rubber is included in the “polymer” concept of the present invention. Conductive carbon black is included in the concept of “conductive filler” of the present invention. Each of the lower electrodes 01Y to 16Y has a strip shape. The lower electrodes 01Y to 16Y each extend in the front-rear direction. The lower electrodes 01Y to 16Y are arranged in the left-right direction so as to be substantially parallel to each other at a predetermined interval.

  A total of 16 lower wires 01y to 16y are arranged on the lower surface of the sensor thin film 51. The lower wirings 01y to 16y are each formed including acrylic rubber and silver powder. Each of the lower wirings 01y to 16y has a linear shape. The lower wiring connector 55 is disposed at the right rear corner of the sensor thin film 51. The lower wirings 01y to 16y connect the rear ends of the lower electrodes 01Y to 16Y and the lower wiring connector 55, respectively.

  The lower insulating coating layer 53 is disposed below the sensor thin film 51. The lower insulating coating layer 53 is formed including acrylic rubber. The lower insulating coating layer 53 has a sheet shape. The lower insulating coating layer 53 covers the sensor thin film 51, the lower electrodes 01Y to 16Y, and the lower wirings 01y to 16y from below.

  As shown by hatching in FIG. 4, the detectors A0101 to A1616 are arranged at portions (overlapping portions) where the upper electrodes 01X to 16X and the lower electrodes 01Y to 16Y intersect when viewed from above or below. ing. Each of the detection units A0101 to A1616 includes a part of the upper electrodes 01X to 16X, a part of the lower electrodes 01Y to 16Y, and a part of the sensor thin film 51. A total of 256 (= 16 × 16) detectors A0101 to A1616 are arranged. The detection units A0101 to A1616 are arranged over substantially the entire surface of the sensor 5.

(Control unit 4)
The control unit 4 includes a power supply circuit 41, a CPU (Central Processing Unit) 42, a RAM (Random Access Memory) 43, a ROM (Read Only Memory) 44, and a drive circuit 45.

  The power supply circuit 41 applies a sinusoidal AC voltage to the detection units A0101 to A1616. The AC voltage is sequentially applied to the detection units A0101 to A1616 in a scanning manner. The ROM 44 stores in advance a map indicating the correspondence between the capacitance and the body pressure (load) in the detection units A0101 to A1616. The RAM 43 temporarily stores the impedance and phase input from the upper wiring connector 54 and the lower wiring connector 55. The CPU 42 extracts the capacitances of the detection units A0101 to A1616 based on the impedance and phase stored in the RAM 43. Then, the body pressure distribution in the sensor 5 is calculated from the capacitance.

  As shown in FIG. 3, the drive circuit 45 is connected to the pump 300 and the supply / discharge switching valve 301 of the supply / discharge unit 30 of the body pressure adjusting unit 3. Further, the pressure is input to the control unit 4 as an electrical signal from the pressure gauge 302 of the supply / discharge unit 30 of the body pressure adjusting unit 3.

[Calculation method of maximum value of body pressure distribution]
Next, a method for calculating the maximum value of the body pressure distribution of the mattress according to the present embodiment will be described. The maximum value of the body pressure distribution is calculated by the control unit 4. First, the control unit 4 selects the air cell 20 (single or plural) to be decompressed from a total of 24 air cells 20. Next, the plurality of detection units A0101 to A1616 arranged above the air cell 20 are selected from a total of 256 detection units A0101 to A1616. Then, the body pressure is calculated for each of the detection units A0101 to A1616 from the capacitance of the detection units A0101 to A1616. Then, the maximum value is determined from the calculated plurality of body pressures. In this way, the maximum value of the body pressure distribution is calculated.

[Mattress movement]
Next, the movement when reducing the internal pressure of the air cell of the mattress of this embodiment will be described. FIG. 6 shows a correspondence diagram of the state of the air cell, the internal pressure of the air cell, the maximum value of the body pressure distribution, the first-order time differential value, and the second-order time differential value. In FIG. 6, time advances from the left side to the right side. Further, the air cell state refers to the state of the air cell indicating the maximum value of the body pressure distribution. As described above, the maximum value of the body pressure distribution is calculated by the control unit 4. Further, the internal pressure of the air cell 20 is detected by a pressure gauge 302.

  As shown in FIG. 6, when the internal pressure of the air cell 20 is reduced, the state of the air cell 20 is changed from the pre-setting constant pressure state B1 (point D1, the section on the left side from the descending section start point E1) to the reduced pressure state B2 (point D1, It switches to the section from the descending section start point E1 to the point D3 and the rising section start point E4).

(Constant pressure before setting B1)
In the pre-setting constant pressure state B1, the pump 300 is stopped as shown in FIG. Further, the pump 300 and the air cell 20 are connected via the main hose 305. In addition, as shown in FIG. 6, the air cell 20 has a substantially constant shape. Note that, due to the weight of the bedridden M, the air cell 20 is slightly crushed compared to the no-load state (the state in which no load is input) indicated by the alternate long and short dash line. Moreover, the internal pressure of the air cell 20 is kept substantially constant. Further, the maximum value of the body pressure distribution is kept substantially constant. Further, the first-order time differential value and the second-order time differential value of the maximum value of the body pressure distribution are substantially zero.

(Decompression state B2)
When switching from the pre-setting constant pressure state B1 to the decompression state B2, the supply / discharge unit 30 corresponding to the air cell 20 to be decompressed is driven as shown in FIG. That is, the supply / discharge switching valve 301 is switched by the drive circuit 45 of the control unit 4. Then, the main hose 305 and the exhaust hose 306 are connected. By the connection, the air in the air cell 20 is exhausted to the outside through the main hose 305 and the exhaust hose 306. For this reason, as shown in FIG. 6, the air cell 20 begins to collapse. Further, the internal pressure of the air cell 20 starts to be reduced. Moreover, the maximum value of the body pressure distribution starts to decrease. Moreover, the first-order time differential value and the second-order time differential value of the maximum value of the body pressure distribution are negative.

  In the reduced pressure state B2, the maximum values of the body pressure distribution are as follows: the descending section (the section from the descending section start point E1 to the constant pressure section start point E3) and the constant pressure section C1 (the constant pressure section start point E3 to the ascending section start point E4). Section).

  In the first period B20 (point D1, the section from the descending section start point E1 to the point D2) in the decompressed state B2, the air cell 20 continues to be crushed. Further, the internal pressure of the air cell 20 continues to be reduced. Moreover, the maximum value of the body pressure distribution continues to decrease. The maximum value of body pressure distribution changes from negative to positive (the curve shape of the maximum value of body pressure distribution changes from “convex upward” to “convex downward”). Passes the music point E2. The first-order time differential value of the maximum value of the body pressure distribution remains negative.

  In the latter period B21 (section from point D2 to point D3) of the decompression state B2, the air cell 20 continues to be crushed. On the other hand, the internal pressure of the air cell 20 has dropped to substantially atmospheric pressure. For this reason, the internal pressure of the air cell 20 remains substantially constant. Further, the maximum value of the body pressure distribution becomes substantially constant from the constant pressure section start point E3 with a slight delay from the internal pressure of the air cell 20. That is, the first-order time differential value and the second-order time differential value of the maximum value of the body pressure distribution are substantially zero.

(Bottomed state B3)
As described above, in the latter period B21 of the reduced pressure state B2, the internal pressure of the air cell 20 remains substantially constant. For this reason, if only the internal pressure of the air cell 20, that is, the pressure of the pressure gauge 302 is managed, the pressure reduction state B2 shifts to the bottomed state B3 (the right section from the rising section start point E4).

  In the transition period, the maximum value of the body pressure distribution passes through the rising section (the section from the rising section start point E4 to the rising section end point E6). That is, the maximum value of the body pressure distribution starts to increase at the rising section start point E4. Immediately after passing through the rising section start point E4, the first-order time differential value and the second-order time differential value of the maximum value of the body pressure distribution are positive. After that, the maximum value of the body pressure distribution rises when the second-order time differential value shifts from positive to negative (the curve shape of the body pressure distribution maximum value changes from “convex downward” to “convex upward”). Pass the section inflection point E5. Note that the first-order time differential value of the maximum value of the body pressure distribution remains positive.

  In the bottomed state B3, the upper wall and the lower wall of the air cell 20 are pressed in a wide area. That is, the air cell 20 is completely crushed. Further, the internal pressure of the air cell 20 continues to be substantially constant from the latter stage B21 of the reduced pressure state B2. Further, the maximum value of the body pressure distribution becomes substantially constant from the rising section end point E6. Moreover, the first-order time differential value and the second-order time differential value of the maximum value of the body pressure distribution are substantially zero.

(Internal pressure setting mode F1, bottoming suppression mode F2)
Thus, even if only the internal pressure of the air cell 20 is managed, the transition from the reduced pressure state B2 to the bottomed state B3 cannot be detected. In this regard, the control unit 4 of the mattress 1 of the present embodiment can be switched between the internal pressure setting mode F1 and the bottoming suppression mode F2.

  The controller 4 switches to the internal pressure setting mode F1 immediately after the maximum value of the body pressure distribution passes through the constant pressure section start point E3. In the internal pressure setting mode F1, the internal pressure of the air cell 20 is maintained at the same value as the internal pressure in the constant pressure section. That is, the internal pressure of the air cell 20 is maintained in a low state. Specifically, as shown in FIG. 3, the supply / discharge switching valve 301 of the supply / discharge unit 30 corresponding to the air cell 20 to be depressurized is switched by the drive circuit 45 of the control unit 4. Then, the main hose 305 and the exhaust hose 306 are shut off.

  In the internal pressure setting mode F1, even when the internal pressure is kept low, for example, when the bedridden M turns over, body pressure concentrates on the specific air cell 20. For this reason, it is easy to be in the bottomed state B3. Further, even when the air cell 20 is under reduced pressure, the bottomed state B3 is likely to occur. In such a case, the control unit 4 switches to the bottoming suppression mode F2.

  In the bottoming suppression mode F2, the internal pressure of the air cell 20 is increased as shown by a dotted line in FIG. 6 so that the air cell 20 is not held in the bottomed state B3. The control unit 4 switches to the bottoming suppression mode F2 immediately after the maximum value of the body pressure distribution passes through the rising section start point E4 due to some circumstances (the bedridden M turns over, the air cell 20 is depressurized, etc.). . In the bottoming suppression mode F2, as shown in FIG. 3, the supply / discharge unit 30 corresponding to the air cell 20 to be pressurized is driven. Specifically, first, the pump 300 and the air cell 20 are connected via the main hose 305. Subsequently, the pump 300 is driven by the drive circuit 45 of the control unit 4. Then, air is supplied into the air cell 20. Thus, in the bottoming suppression mode F2, the internal pressure of the air cell 20 that has been crushed is increased. That is, the air cell 20 is prevented from being held in the bottomed state B3. When the internal pressure of the air cell 20 returns to the allowable value, the control unit 4 switches from the bottoming suppression mode F2 to the internal pressure setting mode F1 again. That is, the control unit 4 resets the internal pressure of the air cell 20.

[Function and effect]
Next, the effect of the mattress of this embodiment is demonstrated. According to the mattress 1 of the present embodiment, as shown in FIG. 6, the internal pressure of the air cell 20 can be set low by paying attention to the characteristic change in the maximum value of the body pressure distribution. For this reason, the body pressure of the bedridden M can be dispersed.

  Further, the controller 4 switches to the internal pressure setting mode F1 in the vicinity of the constant pressure section start point E3 of the constant pressure section C1 in the internal pressure setting section (section from the descending section start point E1 to the rising section start point E4). For this reason, it can suppress that the air cell 20 is pressure-reduced excessively. Moreover, the internal pressure of the air cell 20 in the constant pressure section C1 where the maximum value of the body pressure distribution is minimized can be maintained.

  Further, the control unit 4 immediately switches to the bottoming suppression mode F2 after passing through the internal pressure setting section (after passing through the rising section start point E4). In the bottoming suppression mode F2, it is possible to suppress the air cell 20 from being held in the bottomed state B3. For this reason, while the internal pressure of the air cell 20 can be set low, it can suppress that the air cell 20 is hold | maintained with the bottomed state B3.

  The sensor thin film 51 of the sensor 5 is made of urethane rubber. For this reason, the sensor 5 is flexible and has elasticity. Therefore, the sensor 5 is easily deformed along the body of the bedridden M. Therefore, the bedridden M hardly feels a sense of incongruity such as hardness and stiffness. Further, the sensor 5 is easily deformed following the movement of the bedridden M's body. For this reason, the detection accuracy of the body pressure distribution is high.

  The upper electrodes 01X to 16X and the lower electrodes 01Y to 16Y of the sensor 5 include acrylic rubber. Therefore, the upper electrodes 01X to 16X and the lower electrodes 01Y to 16Y can expand and contract together with the sensor thin film 51. Therefore, the upper and lower electrodes 01X to 16X and the lower electrodes 01Y to 16Y are less likely to restrict the expansion and contraction of the sensor thin film 51. Moreover, the stretchability of the whole sensor 5 becomes larger. For this reason, the sensor 5 is easily deformed along the body of the bedridden M. In addition, the sensor 5 easily follows and deforms the body movement of the bedridden M. Further, according to the mattress 1 of the present embodiment, the body pressure distribution can be calculated from the change in the capacitance of the sensor 5.

  The upper insulating coating layer 52 and the lower insulating coating layer 53 of the sensor 5 contain acrylic rubber. For this reason, the upper insulating coating layer 52 can expand and contract together with the upper electrodes 01X to 16X. In addition, the lower insulating coating layer 53 can expand and contract together with the lower electrodes 01Y to 16Y. For this reason, the upper insulating coating layer 52 and the lower insulating coating layer 53 are less likely to restrict the expansion and contraction of the upper electrodes 01X to 16X and the lower electrodes 01Y to 16Y. Moreover, the stretchability of the whole sensor 5 becomes larger. For this reason, the sensor 5 is easily deformed along the body of the bedridden M. In addition, the sensor 5 easily follows and deforms the body movement of the bedridden M.

  The upper electrodes 01X to 16X and the lower electrodes 01Y to 16Y are both strip-shaped. In addition, the detection units A0101 to A1616 are arranged using the intersections between the upper electrodes 01X to 16X and the lower electrodes 01Y to 16Y. For this reason, the number of electrodes and the number of wirings can be reduced. That is, a total of 256 detection units A0101 to A1616 are arranged in the sensor 5. Here, if electrodes are arranged for each of the detection units A0101 to A1616, 256 upper electrodes and 256 lower electrodes are required. On the other hand, according to the sensor 5 of the present embodiment, in order to secure 256 detectors A0101 to A1616, a total of 32 upper electrodes 01X to 16X and lower electrodes 01Y to 16Y (= 16 + 16). ) Just place it. For this reason, the number of arrangement of electrodes and wirings is reduced. In addition, the number and arrangement density of the detection units A0101 to A1616 can be adjusted only by changing the number and arrangement of the upper electrodes 01X to 16X and the lower electrodes 01Y to 16Y. Therefore, the desired sensor 5 can be easily configured according to the number and size of the air cells 20.

  Air is used for adjusting the internal pressure of the air cell 20. For this reason, compared with the case where liquid (water etc.) is used for internal pressure adjustment, the weight of the cell unit 2 becomes light. A cushion mat 91 is disposed on the upper surface of the sensor 5. In other words, the cushion mat 91 is interposed between the bedridden M and the sensor 5. The cushion mat 91 is excellent in air permeability. For this reason, it is difficult for moisture to remain between the sensor 5 and the bedridden M. As a result, bedsores can be suppressed and sleeping comfort is improved.

<Second embodiment>
The difference between the mattress of the present embodiment and the mattress of the first embodiment is only the trajectory of the change in the maximum value of the body pressure distribution when the internal pressure of the air cell is reduced. Here, only differences will be described.

  FIG. 7 shows a correspondence diagram of the state of the air cell, the internal pressure of the air cell, the maximum value of the body pressure distribution, the first-order time differential value, and the second-order time differential value when the internal pressure of the air cell is reduced. In addition, about the site | part corresponding to FIG. 6, it shows with the same code | symbol.

  As shown in FIG. 7, the maximum value of the body pressure distribution passes through the straight section G1 while changing from the descending section start point E1 to the constant pressure section start point E3. In this case, the end point of the straight section G1 is set as the descending section inflection point E2. The slope of the maximum value of the body pressure distribution in the straight section G1 is negative. That is, the first-order time differential value of the maximum value is negative. In addition, the maximum second-order time differential value in the straight section G1 is approximately zero.

  Further, the maximum value of the body pressure distribution passes through the straight section G2 while changing from the rising section start point E4 to the rising section end point E6. In this case, the starting point of the straight section G2 is set as the rising section inflection point E5. The slope of the maximum value of the body pressure distribution in the straight section G2 is positive. That is, the maximum first-order time differential value is positive. In addition, the maximum second-order time differential value in the straight section G2 is substantially zero.

  The mattress according to the present embodiment has the same functions and effects as those of the mattress according to the first embodiment with respect to portions having a common configuration. Moreover, like the mattress of this embodiment, the maximum value of the body pressure distribution may pass through the straight sections G1 and G2.

<Third embodiment>
The difference between the mattress of the present embodiment and the mattress of the first embodiment is only the trajectory of the change in the maximum value of the body pressure distribution when the internal pressure of the air cell is reduced. Here, only differences will be described.

  FIG. 8 shows a correspondence diagram of the state of the air cell, the internal pressure of the air cell, the maximum value of the body pressure distribution, the first-order time differential value, and the second-order time differential value when the internal pressure of the air cell is reduced. In addition, about the site | part corresponding to FIG. 6, it shows with the same code | symbol.

  As shown in FIG. 8, the maximum value of the body pressure distribution passes through the slope section C2 (section between the slope section start point E30 and the slope section end point E40) instead of the constant pressure section C1 (see FIG. 6). To do. The first-order differential value of the maximum value in the inclined section C2 is negative. Further, the second-order differential value of the maximum value in the inclined section C2 is substantially zero.

  The mattress according to the present embodiment has the same functions and effects as those of the mattress according to the first embodiment with respect to portions having a common configuration. Moreover, like the mattress of the present embodiment, the maximum value of the body pressure distribution may pass through the inclined section C2.

<Fourth embodiment>
The difference between the mattress of this embodiment and the mattress of the first embodiment is only the configuration of the sensor. Here, the difference will be described. FIG. 9 shows a cross-sectional view of the mattress sensor of the present embodiment. In addition, about the site | part corresponding to FIG. 5, it shows with the same code | symbol.

  As shown in FIG. 9, the sensor 5 includes an upper electrode protective layer 520, an upper substrate 521, a lower electrode protective layer 530, and a lower substrate 531. The upper substrate 521 is made of silicone rubber and has a rectangular film shape that is long in the front-rear direction. The upper electrodes 01X to 16X and the upper wiring are disposed on the lower surface of the upper substrate 521. The upper electrode protective layer 520 is made of silicone rubber. The upper electrode protective layer 520 covers the upper electrodes 01X to 16X and the upper wiring from the lower side. The lower substrate 531 is made of silicone rubber and has a rectangular film shape that is long in the front-rear direction. The lower electrode 09Y and the lower wiring are disposed on the upper surface of the lower substrate 531. The lower electrode protective layer 530 is made of silicone rubber. The lower electrode protective layer 530 covers the lower electrode 09Y and the lower wiring from the upper side. The sensor thin film 51 is made of urethane foam.

  The mattress according to the present embodiment has the same functions and effects as those of the mattress according to the first embodiment with respect to portions having a common configuration. Like the mattress of this embodiment, the upper electrode protective layer 520 is between the upper electrodes 01X to 16X and the sensor thin film 51, and the lower electrode protective layer 530 is between the lower electrode 09Y and the sensor thin film 51, respectively. Even if it is interposed, in other words, the upper electrode 01X to 16X and the lower electrode 09Y may be “indirectly” connected to the sensor thin film 51. According to the mattress of this embodiment, even when it is difficult to arrange electrodes and wiring on the sensor thin film 51 (for example, when the sensor thin film 51 is made of foam), the electrodes and wiring are arranged on the upper substrate 521 and the lower substrate 531. Can be arranged.

<Fifth embodiment>
The difference between the mattress of the present embodiment and the mattress of the first embodiment is that the sensor configuration is different. Only the differences will be described here. FIG. 10 shows a top view of the mattress sensor of the present embodiment. As illustrated in FIG. 10, the sensor 7 includes a substrate 76, a sensor thin film 77, a connector 78, electrodes 01 a to 16 a, 01 b to 16 b, 01 c to 16 c, 01 d to 16 d, and wiring 79. .

  The substrate 76 is made of an elastomer and has a rectangular plate shape. The substrate 76 can be elastically deformed. The sensor thin film 77 is disposed on the upper surface of the substrate 76. The sensor thin film 77 is made of an ethylene-propylene-diene terpolymer (EPDM) blended with a conductive filler and has a rectangular film shape. The content ratio of the conductive filler in the sensor thin film 77 is about 45 vol% when the volume of the sensor thin film 77 is 100 vol%. In the no-load state, the sensor thin film 77 has high conductivity. On the other hand, when the load is applied and the sensor thin film 77 is deformed, the contact state between the conductive fillers changes. As a result, the three-dimensional conductive path collapses, and the electrical resistance of the sensor thin film 77 increases. That is, the electrical resistance of the sensor thin film 77 increases as the amount of elastic deformation increases. The connector 78 has a square plate shape. The connector 78 is disposed at the right rear corner of the upper surface of the substrate 76.

  The electrodes 01a to 16a are arranged on the left side of the sensor thin film 77 at a predetermined interval. The electrodes 01b to 16b are arranged on the right side of the sensor thin film 77 at a predetermined interval. The electrodes 01a to 16a and the electrodes 01b to 16b are opposed to each other in the left-right direction, as indicated by a dashed line in FIG.

  The electrodes 01c to 16c are arranged on the rear side of the sensor thin film 77 at a predetermined interval. The electrodes 01d to 16d are arranged on the front side of the sensor thin film 77 at a predetermined interval. The electrodes 01c to 16c and the electrodes 01d to 16d are opposed to each other in the front-rear direction, as indicated by a dashed line in FIG. The intersection of these alternate long and short dash lines (total 256 = 16 × 16) is a detection unit. The electrodes 01a to 16a, 01b to 16b, 01c to 16c, 01d to 16d, and the connector 78 are connected by a wiring 79, respectively.

  The control unit 8 includes a power supply circuit 81, a CPU 82, a RAM 83, a ROM 84, and a drive circuit 85. The control unit 8 is electrically connected to the connector 78. The ROM 84 stores in advance a map showing the correspondence between the electrical resistance and body pressure (load) in the detection unit. The power supply circuit 81 applies a DC voltage to the detection unit. The direct-current voltage is sequentially applied to a total of 256 detection units in a scanning manner. The electrical resistance of each detection unit is temporarily stored in the RAM 83. The CPU 82 calculates the load distribution of the sensor thin film 77 from the electrical resistance stored in the RAM 83. The drive circuit 85 is connected to the pump 300 and the supply / discharge switching valve 301 of the supply / discharge unit 30 of the body pressure adjusting unit 3 as shown in FIG. Further, the pressure is input as an electrical signal from the pressure gauge 302 of the supply / discharge unit 30 to the control unit 8.

  The mattress according to the present embodiment has the same functions and effects as those of the mattress according to the first embodiment with respect to portions having a common configuration. Further, according to the mattress of the present embodiment, the body pressure distribution can be calculated from the change in the electrical resistance of the sensor 7.

<Others>
The embodiment of the mattress of the present invention has been described above. However, the embodiment is not particularly limited to the above embodiment. Various modifications and improvements that can be made by those skilled in the art are also possible.

  In the above embodiment, the starting point (switching point) of the internal pressure setting mode F1 is set in the constant pressure section C1, but the starting point may be set between the descending section inflection point E2 and the rising section start point E4. Good. The starting point of the internal pressure setting mode F1 only needs to be set in the internal pressure setting section (the section from the descending section start point E1 to the rising section start point E4).

  In the above embodiment, the starting point (switching point) of the bottoming suppression mode F2 is set immediately after passing through the constant pressure section C1, but may be set to a section from the rising section start point E4 to the rising section end point E6.

  The number of air cells 20 to be depressurized is not particularly limited. It may be single. In addition, all 24 air cells 20 may be subject to pressure reduction. Alternatively, the 24 air cells 20 may be divided into a plurality of groups, and the pressure reduction target may be set for each group. If it carries out like this, the number of arrangement | positioning of the supply / discharge unit 30 will decrease. For example, if a group switching valve is provided at the downstream end of the main hose 305 and the group switching valve and the air cell 20 belonging to each group are branched and connected, the group switching valve selectively connects the main hose and the air cell 20 belonging to each group. Can be communicated to. For this reason, the internal pressure of all the air cells 20 can be adjusted with the single supply / discharge unit 30. In the internal pressure setting mode F1, it is preferable to shut off the plurality of air cells 20 from each other. If it carries out like this, the movement of the air by the internal pressure difference between the air cells 20 can be suppressed.

  In the second embodiment, the end point of the straight section G1 is set as the descending section inflection point E2, but the starting point E8 of the straight section G1 may be set as the descending section inflection point E2. That is, when there are a plurality of candidate points that meet the condition of the descending section inflection point E2, the descending section inflection point E2 may be arbitrarily determined from the plurality of candidate points. For example, when there are five candidate points for the descending section inflection point E2, and the fourth point is determined as the descending section inflection point E2 in time order, the number of candidate points through which the maximum value of the body pressure distribution passes is controlled. It is only necessary to count in the parts 4 and 8 and determine the fourth point as the descending section inflection point E2.

  Further, the configuration, shape, size, and the like of the sensors 5 and 7 are not particularly limited. The amount of electricity output from the sensors 5 and 7 may be any of voltage, electrical resistance, capacitance, and the like. The voltage applied to the detection unit by the power supply circuits 41 and 81 may be alternating current or direct current. The voltage waveform may be sinusoidal or rectangular.

  In the sensors 5 and 7, the type of polymer of the sensor thin films 51 and 77 is not particularly limited. For example, in the capacitance-type sensor 5 of the first and second embodiments, an elastomer having a large elongation, strength, and relative dielectric constant is used from the viewpoint of durability against repeated expansion and contraction and capacitance. It is desirable. For example, silicone rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, natural rubber, isoprene rubber, foams thereof, and urethane foam are suitable. It is.

  The sensor thin film 51 may be made of a polymer other than the elastomer, for example, a stretchable cloth. In this case, when a load is applied to the sensor thin film 51, a gap between fibers constituting the cloth is crushed, and the thickness of the cloth is reduced. That is, the thickness of the sensor thin film 51 is reduced. Thereby, the distance between the upper electrodes 01X to 16X and the lower electrodes 01Y to 16Y is reduced. As a result, the capacitance between the upper electrodes 01X to 16X and the lower electrodes 01Y to 16Y (capacitance of the detection units A0101 to A1616) increases, and the load is detected.

  The cloth may be any of woven cloth, knitted cloth, and non-woven cloth as long as it has elasticity. By using a cloth, the sensor thin film 51 excellent in stretch flexibility can be realized at a relatively low cost. Moreover, there is a gap between the fibers constituting the cloth. For this reason, even when pressed with a small load, the thickness of the cloth is likely to change due to the crushing of the gap. Therefore, the sensor thin film 51 has high detection sensitivity and excellent response. The sensor thin film 51 may be a single layer or multiple layers. In the case of multiple layers, dielectric layers made of different materials may be used.

  In the resistance change type sensor 7 of the fifth embodiment, considering compatibility with the conductive filler, silicone rubber, ethylene-propylene copolymer rubber, natural rubber, styrene-butadiene copolymer rubber, acrylonitrile- Butadiene copolymer rubber and acrylic rubber are suitable. In the fifth embodiment, the electrical resistance of the sensor thin film 77 increases as the amount of elastic deformation (load) increases. However, a sensor thin film 77 whose electric resistance decreases as the load increases may be used. The behavior of the electric resistance of the sensor thin film 77 can be adjusted according to the type of elastomer of the base material, the type and blending amount of the conductive filler, and the like.

  Moreover, the material of the upper substrate 521 and the lower substrate 531 is not particularly limited. An insulating resin or elastomer may be used. For example, polyamide, polyethylene, polyester, polyurethane, polyvinyl chloride, acrylic rubber, urethane rubber, silicone rubber, ethylene propylene copolymer rubber, natural rubber, styrene-butadiene rubber, acrylonitrile butadiene rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, Chlorinated polyethylene rubber or butyl rubber may be used. Note that the electrodes and wiring may be printed on the upper substrate 521 and the lower substrate 531.

  In the sensor 5 of the first and second embodiments, the electrode and the wiring are formed including an elastomer. In this case, since the electrode and the wiring expand and contract, there is an advantage that the sensor thin film 51 can be integrally deformed.

  The material of the polymer used for the electrode and wiring is not particularly limited. Polymers include silicone rubber, ethylene-propylene copolymer rubber, natural rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, etc. It may be an elastomer. The polymer may be a resin such as polyester or epoxy. This increases the stretchability of the electrode. For this reason, the electrode and the sensor thin film 51 are easily bent and stretched integrally.

  The material of the conductive filler used for the electrode and wiring is not particularly limited. The conductive filler may be one or more selected from carbon materials and metals. As the metal, highly conductive silver, copper, or the like is preferable. Therefore, as the conductive filler, fine particles such as silver and copper, or fine particles having a surface plated with silver or the like can be used. Carbon materials have good conductivity and are relatively inexpensive. For this reason, when the conductive filler made of a carbon material is used, the manufacturing cost of the sensors 5 and 7 can be reduced. Examples of the carbon material include conductive carbon black, carbon nanotubes, carbon nanotube derivatives, graphite, and conductive carbon fibers. In particular, conductive carbon black, graphite, and conductive carbon fiber have good conductivity and are relatively inexpensive. For this reason, when these materials are used, the manufacturing cost of the sensors 5 and 7 and the mattress 1 can be reduced. Moreover, you may form an electrode and wiring with the metal material, the material which gave the metal plating to the surface of organic fiber, etc.

  In any of the embodiments, the number of electrodes and the arrangement location are not particularly limited. For example, in the sensor 5 of the first and second embodiments, the number, width, and length of the strip-shaped upper electrodes 01X to 16X and the lower electrodes 01Y to 16Y may be determined as appropriate. For example, a large width and a small width may be mixed and arranged. Moreover, what is necessary is just to adjust the number and arrangement | positioning of detection part A0101-A1616 by changing the arrangement | positioning form of upper electrode 01X-16X and lower electrode 01Y-16Y.

  In the above embodiment, the body pressure distribution is detected by the single-layer sensors 5 and 7. However, the body pressure distribution may be detected by using sensors 5 and 7 having two or more layers. For example, the sensors 5 and 7 in which the detectors are densely arranged and the sensors 5 and 7 in which the detectors are sparsely arranged are prepared separately, and the former is arranged in a portion where the bed slip is likely to occur. The other part may be disposed in other parts.

  Moreover, in the said embodiment, the body pressure distribution of the whole body of the bedridden M was detected, and the dispersion | distribution of body pressure and the conversion of the posture were performed. However, the sensors 5 and 7 may be arranged only in a region where bed slip is likely to occur to perform dispersion of body pressure or conversion of body position.

  In the above embodiment, the sensors 5 and 7 are disposed on the upper surface of the cover 6. However, the sensors 5 and 7 may be disposed below the cover 6. Further, the sensors 5 and 7 may be arranged inside the cover 6. The sensors 5 and 7 and the cover 6 may or may not be bonded as a whole. When the sensors 5 and 7 are arranged on the upper surface of the cover 6, it is preferable that the sensors 5 and 7 are not bonded together so that the sensors 5 and 7 can easily follow the movement of the air cell 20. In this case, for example, by fixing a plurality of locations on the outer edges of the sensors 5 and 7 to the cover 6, the displacement of the sensors 5 and 7 can be suppressed.

  In the above embodiment, the cushion mat 91 is disposed on the upper surfaces of the sensors 5 and 7. The material of the cushion mat 91 is not particularly limited as long as it has air permeability and cushioning properties. In addition to the above embodiment, for example, a mat using “breath air (registered trademark)” manufactured by Toyobo Co., Ltd., urethane foam, or the like may be used. Note that the cushion mat 91 may not be disposed.

  Further, a cover may be further disposed so as to cover the upper surface of the cushion mat 91. Thereby, it can suppress that the cushion mat 91 and the mattress 1 become dirty. Moreover, the designability is also improved. In this case, it is desirable that the cover has air permeability.

  In the above embodiment, air is used to adjust the internal pressure of the air cell 20, but other gases such as nitrogen, liquids such as water, oil, and gel may be used. Further, the number, shape, dimensions, etc. of the air cells 20 are not particularly limited. The air cell 20 and the detection units A0101 to A1616 may be arranged to face each other in the vertical direction. Further, instead of the pump 300, another blower such as a compressor or a blower may be arranged.

1: Mattress, 2: Cell unit, 3: Body pressure adjustment unit, 4: Control unit, 5: Sensor, 6: Cover, 7: Sensor, 8: Control unit, 9: Bed
01X to 16X: Upper electrode, 01Y to 16Y: Lower electrode, 01a to 16a: Electrode, 01b to 16b: Electrode, 01c to 16c: Electrode, 01d to 16d: Electrode, 01x to 16x: Upper wiring, 01y to 16y: Lower wiring, 20: Air cell (cell), 30: Supply / discharge unit, 41: Power supply circuit, 45: Drive circuit, 51: Sensor thin film, 52: Upper insulating coating layer, 53: Lower insulating coating layer, 54: Upper Wiring connector, 55: lower wiring connector, 76: substrate, 77: sensor thin film, 78: connector, 79: wiring, 81: power circuit, 85: drive circuit, 90: bed body, 91: cushion mat.
300: pump, 301: supply / discharge switching valve, 302: pressure gauge, 305: main hose, 306: exhaust hose, 520: upper electrode protective layer, 521: upper substrate, 530: lower electrode protective layer, 531: lower side Substrate, 900: floor board.
A0101 to A1616: Detection unit, B1: Constant pressure state before setting, B2: Depressurized state, B20: Early period, B21: Late period, B3: Bottomed state, C1: Constant pressure section, C2: Inclined section, E1: Lowering section start point, E2: descent section inflection point, E3: constant pressure section start point, E1 to E3: descent section, E30: slope section start point, E4: rise section start point, E40: slope section end point, E5: rise section inflection point E6: Elevating section end point, E4 to E6: Elevating section, E8: Starting point, F1: Internal pressure setting mode, F2: Sole suppression mode, G1: Straight section, G2: Straight section, M: Bedridden

Claims (7)

A cell unit that supports the bedridden person from below and has a plurality of cells through which fluid can enter and exit;
A body pressure adjusting unit that changes the body pressure distribution of the bedridden by changing the internal pressure of the cell;
A sensor thin film that is disposed on at least one of the upper and lower sides of the cell unit and includes a polymer and can be elastically deformed by the body pressure of the bedridden, and a plurality of sensor thin films that are directly or indirectly connected to the sensor thin film A sheet-like sensor capable of detecting, as an electric quantity, the body pressure applied to the plurality of detection units, and a plurality of detection units formed between the plurality of electrodes.
A control unit that controls the body pressure adjustment unit based on the amount of electricity of the sensor and changes the internal pressure of the cell;
A mattress comprising:
When reaching the bottomed state where the cell is completely crushed, the maximum value of the body pressure distribution is lowered so that the first-order time differential value of the maximum value becomes negative as the internal pressure of the cell is reduced. Passing through the section and the rising section in which the first-order time differential value of the maximum value becomes positive due to the bottoming state, in order of time,
The control unit adjusts the body pressure based on the electric quantity of the sensor in an internal pressure setting section between a descending section start point at which the descending section is started and an ascending section start point at which the ascending section is started. The mattress is switched to an internal pressure setting mode for controlling the unit and setting the internal pressure of the cell.   The control unit controls the body pressure adjusting unit based on the amount of electricity of the sensor and increases the internal pressure of the cell after the maximum value of the body pressure distribution passes through the internal pressure setting section. The mattress according to claim 1, wherein the mattress is switched to a sticking suppression mode. In the descending section, a descending section inflection point at which the second-order time differential value of the maximum value shifts from negative to positive is set,
The mattress according to claim 1 or 2, wherein the control unit switches to the internal pressure setting mode after passing through the descending section inflection point. In the internal pressure setting section, a constant pressure section start point at which the first-order time differential value of the maximum value shifts from negative to 0 and the second-order time differential value of the maximum value shifts from positive to 0 is set.
The mattress according to claim 3, wherein the control unit switches to the internal pressure setting mode after passing through the constant pressure section start point. In the sensor, the plurality of electrodes includes a strip-shaped upper electrode disposed on the upper side of the sensor thin film, and a strip-shaped lower electrode disposed on the lower side of the sensor thin film,
The plurality of detection units are formed by the upper electrode and the lower electrode intersecting when viewed from above or below,
The mattress according to any one of claims 1 to 4, wherein a capacitance of the detection unit is changed by the body pressure.   The mattress according to claim 5, wherein the upper electrode and the lower electrode are formed including a polymer and a conductive filler filled in the polymer. The plurality of cells are divided into a plurality of groups,
The body pressure adjusting unit changes the body pressure distribution of the bedridden person by changing the internal pressure of the plurality of cells in the group unit,
The cell unit and the sensor are arranged so that at least one of the cells overlaps the sensor for each group when viewed from above or below,
The mattress according to any one of claims 1 to 6, wherein the coordinates of the plurality of cells and the coordinates of the plurality of detection units of the sensor are not associated with each other.

Images