a2) United States Patent
`US 6,608,562 B1
`(10) Patent No.:
`Kimuraetal.
`(45) Date of Patent:
`Aug. 19, 2003
`
`
`US006608562B1
`
`(54) VITAL SIGNAL DETECTING APPARATUS
`
`(75)
`
`Inventors: Teiyuu Kimura, Nagoya (JP); Rie
`Ohsaki, Anjo (JP); Shinji Nanba,
`Kariya (JP); Satoshi Takeuchi, Nagoya
`(IP); Seiichi Yamada, Chirya (JP);
`Satoru Kodama, Obu (JP); Masao
`Hasegawa, Okaraki (JP); Masahiko
`Ito, Nagoya (JP); Tsukasa Koumura,
`Toyota (JP)
`
`4/2000 MacKenzie ..........00 340/583
`6,049,282 A *
`
`... 353/10
`8/2000 Trayneret al.
`.....
`6,095,652 A *
`6/2002 Rheeet al. oe. 600/300
`6,402,690 B1 *
`FOREIGN PATENT DOCUMENTS
`1-190332
`7/1989
`5-288869
`11/1993
`8-80288
`3/1996
`8-266493
`10/1996
`9-37056
`2/1997
`9-122090
`5/1997
`
`JP
`JP
`JP
`JP
`JP
`JP
`
`(73) Assignee: Denso Corporation, Kariya (JP)
`
`OTHER PUBLICATIONS
`
`(*) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`US.C. 154(b) by 248 days.
`
`Yamashita et al., “Development of a Ring—Type Vital Sign
`Telemeter,” Technical Report of IEICE, vol. MBE95—-40,
`Jun. 1995, pp. 63-68.
`
`(21) Appl. No.: 09/651,078
`
`(22)
`
`(30)
`
`Filed:
`
`Aug. 30, 2000
`
`Foreign Application Priority Data
`
`Aug. 31,1999
`Sep. 1, 1999
`Sep. 2,1999
`
`(JP)
`(JP)
`(IP)
`
`...
`«. 11-245381
`
`...
`... 11-247316
`ceceeccceecccccssesecestsseesteesieees 11-249025
`
`Tint. C17 eee cceeeeeeeceeeeeeeeeeneene GO8B 23/00
`(SV)
`(52) US. Ch we 340/573.1; 340/539; 600/502;
`600/503; 600/300; 600/344; 600/521; 128/903
`(58) Field of Search oo... 340/573.1, 573.4,
`340/539; 600/502, 503, 344, 300, 309,
`485, 500, 508, 310, 549, 323, 521; 128/903;
`988/411
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`...... 600/503
`4,305,401 A * 12/1981 Reissmuelleret al.
`5,119,072 A *
`6/1992 Hemingway............. 340/573.1
`
`4/1997 White .........
`we. 340/573.4
`5,617,074 A *
`
`4/1998 Lo etal. we 600/521
`5,738,104 A *
`6/1998 Kondo et al... 600/502
`5,766,131 A *
`
`5,982,285 A * 11/1999 Buecheetal. .......... 340/573.1
`
`* cited by examiner
`
`Primary Examiner—Benjamin C. Lee
`(74) Attorney, Agent, or Firm—Posz & Bethards, PLC
`
`(57)
`
`ABSTRACT
`
`A vital signal detecting apparatus comprises an attachable
`device to be attached to a finger, a sensor having a light-
`emitting device and a light-receiving device, and a trans-
`mitting circuit for transmitting a signal wavetorm as a pulse
`wave from the sensor to a pulse wave monitoring unit. The
`pulse wave detecting unit also has an attachment detecting
`circuit for detecting whether or not the attachable device is
`in an attached state by comparing a signal waveform
`obtained when the light-emitting device is on with a signal
`waveform obtained whenthe light-emitting device is off and
`an operation control circuit for controlling the operation of
`the sensor, the transmitting circuit and the attachmentdetect-
`ing circuit. Preferably, the light-transmitting plate is dis-
`posed above the light-emitting device andthe light-receiving
`device to pass light therethrough, and the light transmitting
`plate may be an IR-cutfilter capable of blocking light of
`wavelengths greater than 700 nm.
`
`13 Claims, 22 Drawing Sheets
`
`
`
`APPLE 1012
`
`1
`
`APPLE 1012
`
`

`

`U.S. Patent
`
`Aug. 19, 2003
`
`Sheet 1 of 22
`
`US 6,608,562 B1
`
`FIG. 1A
`
`
`
`
`
` vi , Sy
`
`PooSYS
`VPIKZ
`
`
`
`2
`
`

`

`U.S. Patent
`
`Aug. 19, 2003
`
`Sheet 2 of 22
`
`US 6,608,562 BI
`
`
`
`3
`
`

`

`U.S. Patent
`
`Aug. 19, 2003
`
`Sheet 3 of 22
`
`US 6,608,562 BI
`
`FIG. 3A1
`
`11
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`ak
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`FIG. 3B1
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`21
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`FIG. 3C1
`
`
`
`FIG. 3A2
`
`
`
`FIG. 3B2
`
`FIG. 302
`
`DC
`
`0
`
`FIG. 3D2
`
`
`
`DC
`
`————$——
`
`4
`
`

`

`U.S. Patent
`
`Aug. 19, 2003
`
`Sheet 4 of 22
`
`US 6,608,562 B1
`
`FIG. 4
`
`TURN ON LED AND
`DETECT SIGNAL WAVEFORM
`
`TURN OFF LED AND
`DETECT SIGNAL WAVEFORM
`
`NO
`
`FITTED?
`
`103
`
`YES
`
`DETECT AND TRANSMIT|104,
`PULSE WAVE
`
`\
`
`ELAPSE OF
`
`MEASUREMENT
`TIME?
`
`YES
`
`105
`
`STOP POWER SUPPLY
`
`106
`
`5
`
`

`

`U.S. Patent
`
`Aug.19, 2003
`
`Sheet 5 of 22
`
`US 6,608,562 B1
`
`FIG. 5A
`
`
`
`FIG. 5B
`
`332
`
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`-
`rh36
`31
`=
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`POWER
`SUPPLY
`
` 37
`
`6
`
`

`

`U.S. Patent
`
`Aug.19, 2003
`
`Sheet 6 of 22
`
`US 6,608,562 B1
`
`Y
`
`FIG. 6
`
`32
`
`/
`
`FIG. 8
`
`321
`
`323
`
`Y 325
`
`322
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`
`DISPLAYED
`WAVEFORM
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`
`
`
`DISPLAY 83
`
`FINGER
`NOT INSERTED
`
`
`
`
`
`
`
`NORMAL
`
`NOISE
`INGRESS
`
`7
`
`

`

`U.S. Patent
`
`Aug. 19, 2003
`
`Sheet 7 of 22
`
`US 6,608,562 BI
`
`
`
`AV1dSI1d[Z]JAV1dSIO
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`

`

`U.S. Patent
`
`Aug. 19, 2003
`
`Sheet 8 of 22
`
`US 6,608,562 BI
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`
`
`9
`
`

`

`U.S. Patent
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`Aug.19, 2003
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`Sheet 9 of 22
`
`US 6,608,562 B1
`
`FIG.10
`
`10
`
`10
`
`

`

`U.S. Patent
`
`Aug.19, 2003
`
`Sheet 10 of 22
`
`US 6,608,562 B1
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`™
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`fa
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`

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`U.S. Patent
`
`Aug. 19, 2003
`
`Sheet 11 of 22
`
`US 6,608,562 B1
`
`LEYAMOd
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`

`U.S. Patent
`
`Aug. 19, 2003
`
`Sheet 12 of 22
`
`US 6,608,562 B1
`
`515
`
`10<aa
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`22 =23
`
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`37
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`POWERSUPPLY
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`wy
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`FIG.13
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`91
`
`13
`
`13
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`

`

`U.S. Patent
`
`Aug.19, 2003
`
`Sheet 13 of 22
`
`US 6,608,562 B1
`
`90
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`POWERSUPPLY
`
`FIG.14
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`

`

`U.S. Patent
`
`Aug. 19, 2003
`
`Sheet 14 of 22
`
`US 6,608,562 B1
`
`FIG. 15
`
`Lit
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`yoOY 402
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`if
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`FIG. 16
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`
`15
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`

`

`U.S. Patent
`
`Aug.19, 2003
`
`Sheet 15 of 22
`
`US 6,608,562 B1
`
`FIG. 17
`
`EXTRANEOUS
`LIGHT
`
`F
`
`407
`
`
`FIG. 18
`
`EXTRANEOUS
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`
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`
`16
`
`16
`
`

`

`U.S. Patent
`
`Aug.19, 2003
`
`Sheet 16 of 22
`
`US 6,608,562 B1
`
`FIG. 19
`
`
`
`TRANSMISSIONRATE
`
`
`
`
`
`
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`
`FIG. 20
`
`CmvJ
`2450 an
`
`EXTRANEOUS LIGHT
`
`amet
`
`QUTPUT
`
`2300
`
`a: WITH FILM410
`b: WITHOUT FILM410
`
`2250 1H
`10
`18
`
`20
`TIME [sec]
`
`17
`
`17
`
`

`

`U.S. Patent
`
`Aug.19, 2003
`
`Sheet 17 of 22
`
`US 6,608,562 B1
`
`FIG. 21
`
`EXTRANEOUS
`
`LIGHT
`
`FIG. 22
`
`F
`
`407
`
`d
`O>|412 413
`
`Imm
`
`405
`
`404
`
`18
`
`18
`
`

`

`U.S. Patent
`
`Aug. 19, 2003
`
`Sheet 18 of 22
`
`US 6,608,562 BI
`
`SNOINVYLXAHLM
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`

`

`U.S. Patent
`
`Aug.19, 2003
`
`Sheet 19 of 22
`
`US 6,608,562 B1
`
`FIG. 24
`
`
`
`904b 504a
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`FIG. 25
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`

`

`U.S. Patent
`
`Aug.19, 2003
`
`Sheet 20 of 22
`
`US 6,608,562 B1
`
`FIG. 26
`
`
`
` REESSSN
`TA
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`
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`504b 504a
`
`FIG. 27
`
`501
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`
`21
`
`21
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`

`

`U.S. Patent
`
`Aug. 19, 2003
`
`Sheet 21 of 22
`
`US 6,608,562 B1
`
`FIG. 28A
`
`r
`
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`
`503
`
`FIG. 28B
`903a
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`503a
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`FIG. 28C 303a
`
`22
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`22
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`

`

`U.S. Patent
`
`Aug. 19, 2003
`
`Sheet 22 of 22
`
`US 6,608,562 B1
`
`FIG. 29
`
`501
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`(Meg
`507 Ss
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`
`FIG. 30
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`

`

`1
`VITAL SIGNAL DETECTING APPARATUS
`
`US 6,608,562 B1
`
`2
`be an IR-cut filter capable of blocking light of wavelengths
`greater than 700 nm.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`This invention relates to a vital signal detecting apparatus
`for detecting a vital signal, having an attachable device to be
`attached for example to a finger, an ear, an arm,a leg, torso
`or a neck of a human subject.
`There have been vital signal detecting apparatuses, as
`disclosed, for instance, in JP-A-8-266493 or Electronic Data
`Communications Society, Technical Report 1995-06. To
`check a vital signal (such as a pulse wave), a humansubject
`has to operate an on/off switch himself or herself. If the
`subject operates the on/off switch without inserting a finger
`into the attachable device, because a sensorpicks up external
`noise and outputs an abnormal signal,
`the vital signal
`checking device erroneously determines that the subject is
`abnormal. Further, if a ring part of a pulse wave sensorfails
`even slightly to match the size (thickness) ofthe finger,it is
`difficult for a detecting part to be kept in contact with the
`surface of the finger. Thus, extraneous light, for example,
`sunlight or light from fluorescent lights, affect the measure-
`ment.
`
`The above and other objects, features and advantages of
`the present invention will become more apparent from the
`following detailed description made with reference to the
`accompanying drawings. In the drawings:
`FIGS. 1A and 1B are views showing an attachable device
`of a pulse wave monitoring system of a first preferred
`embodimentof the invention;
`FIG. 2 is a block diagram of the pulse wave monitoring
`system of the first preferred embodiment;
`FIGS. 3A1 through 3D2 are viewsillustrating differences
`between signal waveforms obtained with a light-emitting
`diode ON (FIGS. 3A1 and 3A2, and 3C1 and 3C2) and OFF
`(FIGS. 3B1 and 3B2, and 3D1 and 3D2) with the attachable
`device fitted (FIGS. 3A1 and 3A2, and 3B1 and 3B2) and
`not fitted (FIGS. 3C1 and 3C2, and 3D1 and 3D2) on a
`finger;
`FIG. 4 is a flow chart showing the operation of a pulse
`wavedetecting unit of the pulse wave monitoring system of
`the first preferred embodiment;
`FIG. 5A is a block diagram of an analyzing unit and FIG.
`5B a schematic view of a pulse wave detecting unit of a
`pulse wave analyzing system of a second preferred embodi-
`mentof the invention;
`FIG. 6 is a sectional view showing a switch used in the
`pulse wave detecting unit of the pulse wave analyzing
`system of the second preferred embodiment;
`There have also been vital signal detecting apparatuses,
`FIGS. 7A and 7B are flow charts showing the operation of
`used when a vital signal (such as the pulse wave) of for
`the pulse wave analyzing system of the second preferred
`embodiment;
`example an elderly or infirm subject is to be monitored over
`a long period, with which an attachable device is attached
`FIG. 8 isa table illustrating a display of the analyzing unit
`for instance to an arm or a leg of the subject andavital signal
`of the pulse wave analyzing system of the second preferred
`detected by a sensoris transmitted to a vital signal checking
`embodiment;
`device by radio waves orthe like. If the elderly or infirm
`FIG. 9 is a schematic view showing a pulse wave detect-
`subject removes the attachable device, because the sensor
`ing unit of a pulse wave analyzing system of a third
`picks up external noise and transmits an abnormalsignal to
`preferred embodiment of the invention;
`the vital signal checking device, again the vital signal
`FIG. 10 is a schematic view showing a pulse wave
`checking device erroneously determines that the subject is
`detecting unit of a pulse wave analyzing system of a fourth
`abnormal.
`preferred embodimentof the invention;
`TIG. 11 is a schematic view showing a pulse wave
`detecting unit of a pulse wave analyzing system of a fifth
`preferred embodiment of the invention;
`FIG. 12 is a schematic view showing a pulse wave
`detecting unit of a pulse wave analyzing system of a sixth
`preferred embodiment of the invention;
`According to the present invention, a vital signal detect-
`FIG. 13 is a schematic view showing a pulse wave
`ing apparatus comprises an attachable device to be attached
`detecting unit of a pulse wave analyzing system of a seventh
`to a finger, a sensor having a light-emitting device and a
`preferred embodimentof the invention;
`light-receiving device, and a transmitting circuit for trans-
`FIG. 14 is a schematic view showing a pulse wave
`mitting a signal waveform as a pulse wave from the sensor
`detecting unit of a pulse wave analyzing system of an eighth
`to a pulse wave monitoring unit.
`preferred embodiment of the invention;
`Preferably,
`the vital signal detecting unit also has an
`FIG. 15 is a sectional view of a pulse wave sensor
`attachment detecting circuit for detecting whether or not the
`constituting a ninth preferred embodimentof the invention;
`attachable device is in an attached state by comparing a
`FIG. 16 is a view showing the pulse wave sensor in use;
`signal waveform obtained whenthe light-emitting device is
`FIG. 17 is a schematic view of a pulse wave sensor
`on with a signal waveform obtained whenthe light-emitting
`
`device is off and an operation control circuit for controlling constituting a tenth preferred embodiment, whereinalight-
`the operation of the sensor, the transmitting circuit and the
`receiving device is lowered with respect
`to a light-
`attachment detecting circuit.
`transmitting plate;
`Preferably, the light-transmitting plate is disposed above
`FIG. 18 is a schematic view of a pulse wave sensor
`the light-emitting device and the light-receiving device to
`constituting an eleventh preferred embodiment, wherein a
`pass light therethrough, and the light transmitting plate may
`light control film is used;
`
`
`
`CROSS REFERENCE TO RELATED
`APPLICATION
`
`This patent application relates to and incorporation herein
`by reference Japanese Patent Applications No. 11-245381
`filed on Aug. 31, 1999, No. 11-247316 filed on Sep. 1, 1999
`and No. 11-249025 filed on Sep. 2, 1999.
`BACKGROUND OF THE INVENTION
`
`SUMMARYOF THE INVENTION
`
`It is therefore an object of the present invention to provide
`a vital signal detecting apparatus which eliminates problems
`caused by abnormal vital signals detected when an attach-
`able device is not attached.
`
`10
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`15
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`30
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`35
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`40
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`45
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`50
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`55
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`60
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`65
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`24
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`24
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`US 6,608,562 B1
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`10
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`15
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`30
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`3
`FIG. 19 is a characteristic chart of a light control film;
`FIG. 20 is a graph showing the effect of a light control
`film;
`FIG. 21 is a sectional view of pulse wave sensor consti-
`tuting a twelfth preferred embodiment, wherein an IR-cut
`filter is used;
`FIG. 22 is a schematic view of a thirteenth preferred
`embodiment, wherein a window is provided above the
`light-receiving device;
`FIGS. 23A and 23B are graphs showing the influence of
`windowsofdifferent widths on extraneous light;
`FIG. 24 is a sectional view of a pulse wave sensor
`constituting a fourteenth preferred embodimentof the inven-
`tion;
`FIG. 25 is a perspective view of a printed circuit board
`used in the same pulse wave sensor;
`FIG. 26 is a sectional view of a detecting part of the same
`pulse wave sensorfitted to a finger;
`FIG. 27 is a side viewof a pulse wave sensorconstituting
`a fifteenth preferred embodiment of the invention;
`FIGS. 28A through 28C are three elevations of a pulse
`wave sensor constituting a sixteenth preferred embodiment
`of the invention;
`FIG. 29 is a side viewof a pulse wave sensor constituting
`a seventeenth preferred embodimentof the invention; and
`FIG. 30 is a side viewof a pulse wave sensor constituting
`an eighteenth preferred embodiment of the invention.
`DETAILED DESCRIPTION OF THE
`PREFERRED) EMBODIMENTS
`
`4
`the photo diode 23 receives light
`22 is on (FIG. 3A1),
`(shown with dashedlines) reflected by the surface of the skin
`and light (shown with solid lines) returning from inside the
`body having struck blood capillaries 12 or the like, and a
`signal waveform is obtained wherein a d.c. component
`resulting from surface reflection is superposed on a pulse
`component (FIG. 3A2). Whenthe light-cmitting diode 22 is
`off (FIG. 3B1), because there ceasesto be anyreflectedlight,
`the d.c. component and the pulse component both cease to
`exist and the signal waveform becomessubstantially zero
`(FIG. 3B2). Whenthe attachable device 1 is not fitted on the
`finger 11, because the photo diode 23 receives ambientlight
`(FIGS. 3C1, 3D1) whetherthe light-emitting diode 22 is on
`or off, the sensor 2 outputs a signal waveform having a d.c.
`component of the same level in either case (FIGS. 3C2,
`3D2).
`A determination of attachment state is carried out as
`described below in (1). However, it may alternatively be
`carried out as described in (2), in which case the construc-
`tion for carrying out the determination is simpler.
`(1) The d.c. componentof the signal waveform outputted
`by the photo diode 23 whenthe light-emitting diode 22 is on
`is compared with the d.c. componentof the signal waveform
`outputted by the photo diode 23 when the light-emitting
`diode 22 is off. When the d.c. components of the two signal
`waveformsare of the same level (FIGS. 3C2 and 3D2),it is
`determined that the attachable device 1 is notfitted on the
`finger 11. Whenthere is a difference in the d.c. components
`of the two signal waveforms (FIGS. 3A2, 3B2), it is deter-
`mined that the attachable device 1 is fitted on the finger 11.
`(2) The signal outputted by the photo diode 23 when the
`(First Preferred Embodiment)
`light-emitting diode 22 is on is compared with the signal
`outputted by the photo diode 23 when the light-emitting
`A first preferred embodimentof the invention will now be
`diode 22 is off. When the two are of the same level (FIGS.
`described on the basis of FIGS. 1A and 1B through 4.
`3C2 and 3D2), it is determined that the attachable device 1
`As shown in these figures, a pulse wave monitoring
`is not fitted on the finger 11. When there is a difference
`system K is made up of a pulse wave detecting unit A,
`between the two (FIGS. 3A2, 3B2),it is determinedthat the
`having an attachable device 1, a vital signal detecting sensor
`2, an attachment detecting circuit (ADC) 3, an operation
`attachable device 1 is fitted on the finger 11.
`The operation control circuit 4 is a circuit for controlling
`control circuit 4, an amplifier circuit 5, a transmitting circuit
`the operation of the sensor 2, the transmitting circuit 6 and
`(TR) 6 and a timer circuit 7, and a pulse wave monitoring
`the attachment detecting circuit 3. This operation control
`unit B for monitoring a pulse wave.
`The attachable device 1, which is made ofplastic, is a
`circuit 4 causes the attachment detecting circuit 3 to deter-
`mine whetheror not the attachable device 1 is fitted on the
`cylinder shapedlike a ring to be worn onafinger, and has
`an internal diameter such that a base part 111 of a finger 11
`finger 11. When the attachment detecting circuit 3 deter-
`of a subject will fit in its easily and without readily slipping
`minesthat the attachable device 1 is attachedto the finger 11,
`the operation control circuit 4 supplies operating power to
`out (FIG. 1). A surface treatment (such as painting black) for
`preventing the reflection of light has been carried out on the
`the transmitting circuit 6. The amplifier circuit 5 consists of
`inside of this attachable device 1. The sensor 2 has a
`an operational amplifier or the like. This amplifier circuit 5
`amplifies the signal waveform (pulse wave) from the sensor
`2 converted to a voltage Value by a current-voltage converter
`(CVC) 51. The transmitting circuit 6 has an oscillator part,
`a modulator part and a power amplifier part. This transmit-
`ting circuit 6 modulates a carrier wave with the amplified
`signal waveform into a weak radio wave and transmits this
`to the pulse wave monitoring unit B, which is disposed
`remotely. The timer circuit 7 is a circuit in which is stored
`atime at which the pulse waveis to be sampled or a standby
`time. When the time at which the pulse wave is to be
`sampled is reached or the standby time (from a few minutes
`to several hours) ends and thus it becomes sampling time,
`the timer circuit 7 supplies operating power to the attach-
`ment detecting circuit 3 and the operation control circuit 4.
`The pulse wave monitoring unit B has a receiving circuit
`(REC) 81, an analyzing circuit (AC) 82, a display 83,
`recording circuit 84 and a reporting circuit 85, and is
`installed for example in a cornerof a sickroom. The receiv-
`ing circuit $1 is a circuit for demodulating the pulse wave
`
`light-emitting diode 22 and a photo diode 23 mounted in a
`package 21 molded inside the attachable device 1. The
`package 21 is made of black plastic and has a lght-
`transmitting window 221 extending in the finger length
`direction. Light emitted by the light-emitting diode 22
`passes through the skin of the finger 11 into the finger and
`reaches blood capillaries and is partly absorbed and partly
`scattered by reflection and returned from inside the finger,
`and the photo diode 23 is disposed in a position whereit can
`receive this returning light.
`The attachment detecting circuit 3 is a circuit for deter-
`mining whetherthe attachable device 1 is fitted on the finger
`11. This attachment detecting circuit 3 determines whether
`the attachable device 1 is fitted on the finger 11 by compar-
`ing a signal waveform obtained from the photo diode 23
`whenthe light-emitting diode 22 is on with a signal wave-
`form obtained when the light-emitting diode 22 isoff.
`As shownin FIGS. 3A1 through 3D2, whenthe attachable
`device 1 is fitted on the finger 11,if the light-emitting diode
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`wave detected by the sensor 2 with the attachable device 1
`fitted on the finger 11 is appropriately transmitted to the
`pulse wave monitoring unit B. Consequently, erroneous
`determinations of the pulse wave monitoring unit B can be
`prevented. Because it is not necessary for an on/off switch
`for operating the pulse wave detecting unit A at the time of
`pulse wave detection to be operated, the system is casy to
`use.
`
`5
`from the modulating, wave transmitted fromthe transmitting
`circuit 6. ‘The analyzing circuit 82 is a circuit for analyzing
`the demodulated pulse wave. This analyzing circuit 82
`analyzes pulse rate, pulse beat intervals and pulse waveform
`and so on, and finds any irregular pulse or autonomic nerve
`abnormality. The display 83 is a liquid crystal display or the
`like and displays analysis results obtained by the analyzing
`circuit 82. The recording circuit 84 is a device for holding
`pulse wave and analysis data on a storage medium along
`with sample times. The reporting circuit 85 is a circuit for
`alerting a nurse center or the like when a marked abnormal-
`ity is found in analysis data.
`Next, the operation of the pulse wave monitoring system
`K in measuring the pulse wave of a subject using the pulse
`wave detecting unit A will be described on the basis of the
`flow chart of FIG. 4.
`
`The sensor 2 for detecting the pulse wave doubles, as a
`sensor for detecting whether or not the attachable device 1
`is fitted on the finger 11. Consequently, a special sensor for
`detecting the attachmentstate is unnecessary, and the pulse
`wave detecting device A can be made small.
`Because the attachment detecting circuit 3 detects the
`attachment state by comparing the d.c. component of the
`signal waveform of the photo diode 23 obtained when the
`light-emitting diode 22 is on with the d.c. componentof the
`the operation control circuit 4 passes a
`At step 101,
`signal waveform of the photo diode 23 obtained when the
`current throughthe light-emitting diode 22 and thereby turns
`light-emitting diode 22 is off, the attachment state can be
`on the light-emitting diode 22, and the attachment detecting
`detected accurately with a simple circuil construction.
`circuit 3 detects a signal waveform from the photo diode 23
`Becauseat times of standby the supply of operating power
`amplified by the amplifier circuit 5. Astep 102, the operation
`to circuits other than the timer circuit 7 is cut off, the pulse
`control circuit 4 ceases to pass a current through the light-
`waveof a subject can be checked over a long period without
`emitting diode 22 and thereby turns off the light-emitting
`battery replacements having to be carried out.
`diode 22, and the attachmentdetecting circuit 3 again detects
`Further, the standby timeis fixed irrespective of whether
`a signal waveform from the photo diode 23 amplified by the
`the attachment device 1 is fitted or not fitted. Ilowever,
`amplifier circuit 5. The shift from a standbystate to step 101
`alternatively the standby time of when the attachment device
`is made on the basis of a measurement time being reached
`1 is not fitted may be made longer than the standbytime of
`(whereupon the timercircuit 7 supplies operating power ta
`whenthe attachable device 1 isfitted. In this casc, two timers
`the attachment detecting circuit 3 and the operation control
`circuit 4) or a test switch 100 being pushed with a pointed
`are provided to count the respective standby times, and the
`timers are switched between in correspondence with
`object.
`whether or not the attachable device 1 is fitted.
`At step 103 the attachment detecting circuit 3 determines
`whether or not the attachable device 1 is fitted. When it
`(Second Preferred Embodiment)
`determinesthatit is fitted (YES), processing proceedsto step
`Asecond preferred embodimentof the invention will now
`104. Whenit determinesthatit is not fitted (NO), processing
`be described, with reference to FIGS. 5A and 5B through
`FIG. 8.
`proceeds to step 106. Specifically,
`the determination of
`whetheror no the attachable device1is fitted is carried out
`As shownin FIGS. 5A and 5B, a pulse wave analyzing
`by the attachment detecting circuit 3 comparing the d.c.
`system Lis madeup of a pulse wave detecting unit C, having
`componentof the signal waveform obtained whenthelight-
`a fingerinsertion cylinder 10, a signal detection sensor 2 and
`an amplifier circuit 5, an insertion detection circuit 30 for
`emitting diode 22 is on (the signal waveform obtainedat step
`101) with the dic. component of the signal waveform
`attachment state detection, and a power supply circuit 37
`obtained whenthe light-emitting diode 22 is off (the signal
`constituting part of a processing alteration circuit, and a
`pulse wave analyzing unit D for analyzing a pulse wave.
`waveform) obtained at step 102). At step 104, the operation
`control circuit 4 powers the sensor 2, the amplifier circuit 5
`The pulse wave detecting unit C is built into an easily
`and the transmitting circuit 6 and thereby effects detection of
`carryable housing, and for checking a pulse waveit is placed
`on a table or the like at the side of a bed in which a human
`a pulse wave and transmits the detected pulse wave to the
`pulse wave monitoring unit B in the form of a modulated
`subject is lying.
`carrier wave. At step 195 it is determined whether or not a
`The finger insertion cylinder 10, which is made ofplastic,
`measurement time (from a few tens of seconds to several
`is a cylinder mounted onthe top of the pulse wave detecting
`minutes) has elapsed. If the measurement time has elapsed
`unit C, and has an internal diameter such that a base part 111
`(YES), processing procecdsto step 106. If it has not clapsed
`of a finger 11 of a subject will just fit
`in it. A surface
`(NO), processing returns to step 104 and pulse wave detec-
`treatment such as painting black for preventing the reflection
`tion and pulse wave transmission are continued. At step 106,
`of light is carried out on the inside of this finger insertion
`the timer circuit 7 stops the supply of power to the other
`cylinder 10.
`circuits.
`The sensor 2 comprises a light-emitting diode 22 and a
`After that, the timer circuit 7 finishes counting a prede-
`photo diode 23. Light emitted by the light-emitting diode 22
`termined standby time and then the processing of step 101
`passes through the skin of the finger 11 into the finger,
`onward is started again.
`reaches blood capillaries 12 and is partly absorbed and
`the pulse
`According to the first preferred embodiment,
`partly scattered by reflection and returned from inside the
`wave detecting unit A is so constructed that, only when the
`finger. The photo diode 23 is disposed at the bottom of the
`inside of the attachable device 1 where it can receive this
`allachment detecting circuit 3 detects that the attachable
`device 1 is fitted on the finger 11,
`the operation control
`circuit 4 supplies operating powerto the transmitting circuit
`6 and transmits a pulse wave to the pulse wave monitoring
`unit B. Because of this,
`the sensor 2 does not pick up
`external noise and the transmitting circuit 6 does not trans-
`mit this noise to the pulse wave monitoring unit B. A pulse
`
`returning light.
`The amplifier circuit 5 consists of an operational amplifier
`or the like. This amplifier circuit 5 amplifies the signal
`wavetorm (pulse wave) from the photo diode 23 converted
`to a voltage Value by a current-voltage converter circuit 51.
`The transmitting circuit 6 has an oscillator port, a modulator
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`part and a power amplifier part. This transmitting circuit 6
`modulates a carrier wave with the amplified signal wave-
`form into a weak radio wave and transmits this to the pulse
`wave analyzing unit D, which is disposed remotely.
`The insertion detection circuit 30 is made up of a micro-
`computer 31, a switch 32, a planar 33, a spring 34, a plunger
`case 35 and a resistor 36. It determines whether or not the
`finger 11 has been inserted into the finger isertion cylinder
`10. The switch 32, as shownin FIG. 6, is made up of base
`films 321 and 322, electrodes 232 and 324 affixed to the rear
`sides of the base films 321 and 322, and a spacer film 325
`disposed betweenthe electrodes 323 and 324. This switch 32
`is fixed over a circular hole 351, which will be further
`discussed later. The plunger 33 is made up of a spherical part
`331 (shaped to not damagethe finger 11) fitted displaceably
`up and downin a cylindrical part 13 of the finger insertion
`cylinder 10 and having a lower [ace which abuts with the
`upperside of the finger 11, and a rod part 332 on which is
`fitted a spring 34. The plunger case 35 is mounted on the top
`part of the finger insertion cylinder 10, and the circular hole
`351, from whichthe rod part 332 projects, is provided in the
`top face of the plunger case 35.
`Normally, because the spring 34 urges the plunger 33
`downward,the rod part 332 of the plunger 33 does not push
`the switch 32, there is no continuity between the electrodes
`323 and 324, and a voltage V across the electrodes assumes
`a high level. In this case, the microcomputer 31 determines
`that
`the finger 11 has not been inserted into the finger
`insertion cylinder 10. When the finger 11 is inserted into the
`finger insertion cylinder 10, because the plunger 33 shifts
`upward and the rod part 332 pushes the switch 32,
`the
`electrodes 323 and 324 become continuous and the voltage
`V across the two assumes a low level. In this case,
`the
`microcomputer 31 determines that the finger 11 has been
`inserted into the finger insertion cylinder 10 and outputs a
`control signal to the power supply circuit 37.
`The powersupply circuit 37 is a circuit for controlling a
`power supply to the amplifier circuit 5,
`the transmitting
`circuit 6 and the light-emitting diode 22. This power supply
`circuit 37 starts the power supply whenit inputs the control
`signal from the microcomputer 31.
`When during analysis of the pulse wave the finger 11 is
`removed fromthe finger insertion cylinder 10, because the
`microcomputer 31 determines that
`the finger 11 is not
`inserted in the finger insertion cylinder 10, the power supply
`circuit 37 cuts off the power supply to the amplifier circuit
`5, the transmitting circuit 6 and the light-emitting diode 22.
`The pulse wave analyzing unit D has a receiving circuit
`81, an analyzing circuit $2, a display 83 and recording
`circuit $4, and is installed for example in a corner of a
`sickroom. This receiving circuit 81 is a circuit for demodu-
`lating the pulse wave from the modulated wave transmitted
`from the transmitting circuit 6. The analyzing circuit 82 is a
`circuit for analyzing the demodulating pulse wave, and
`alters a part of processing. On the basis of the pulse wave,
`this analyzing circuit 82 computes and analyzes parameters
`(pulse rate, pulse beat intervals and pulse waveforms) mani-
`festing the state of the body, and checks for any irregular
`pulse or autonomic nerve abnormality. The analyzing circuit
`82 does not carry out computation of the parameters based
`on the pulse wave until the pulse wave is demodulated,
`while the detection of insertion/non-insertion ofthe finger 11
`into the finger insertion cylinder 10 is being carried out.
`The display 83 is a liquid crystal display or the like and
`displays the insertion state of the finger 11 and analysis
`results obtained by the analyzing circuit 82. The recording
`circuit 84 is a device for holding pulse wave and analysis
`data on a storage medium along with sample times.
`
`8
`Next, the operation of a pulse wave analyzing system L
`for analyzing the pulse wave of a subject using the pulse
`wave detecting unit C will be described, with reference to
`the flow charts of FIGS. 7A and 7B.
`
`In a signal transmitter side, at step 201, on the basis of the
`voltage V, the microcomputer 31 determines whether or not
`the finger 11 has been inserted into the finger insertion
`cylinder 10, When it determinesthat it has been so inserted
`(YES), processing proceeds to step 202. Whenit determines
`that the finger 11 has not been inserted (NO), processing
`proceeds to step 205.
`At step 202, the power supply circuit 37 starts the power
`supply to the amplifier circuit 5, the transmitting circuit 6
`and the light-emitting diode 22. As a result, pulse wave
`detection processing (step 203) and pulse wave data trans-
`mission processing (step 204) are executed.
`At step 205, the power supplycircuit 37 stops the power
`supply to the amplifier circuit 5, the transmitti