(12) International Application Published Under the Patent Cooperation Treaty
`
`
`(19) World Intellectual Property Organization
`International Bureau
`
`(43) International Publication Date
`October 6, 2005 (10.06.2005)
`
`(51) International Patent Classification: A61B 5/0245 (72) Inventors; and
`(75) Inventors/Applicants: KOTANAGI, Susumu [JP/JP]; c/o
`SEIKO INSTRUMENTS INC., 1-8 Nakase, Mihama-ku, Chi-
`ba-shi, Chiba 2618507 (JP). NAKAMURA, Takashi [JP/JP];
`c/o SEIKO INSTRUMENTS INC., 1-8 Nakase, Mihama-ku,
`Chiba-shi, Chiba 2618507 (JP). MAEGAWA, Kazuya [JP/JP];
`c/o SEIKO INSTRUMENTS INC., 1-8 Nakase, Mihama-ku,
`Chiba-shi, Chiba 2618507 (JP). MIYAHARA, Shinichiro
`[JP/JP]; c/o SEIKO INSTRUMENTS INC., 1-8 Nakase, Miha-
`ma-ku, Chiba-shi, Chiba 2618507 (JP). MORIYA, Koichi
`[JP/JP]; c/o SEIKO INSTRUMENTS INC., 1-8 Nakase, Miha-
`ma-ku, Chiba-shi, Chiba 2618507 (JP).
`
`
`(10) International Publication Number
`WO 2005/092182 A1
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`(21) International Application Number:
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`PCT/JP2005/002021
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`(22) International Filing Date:
`
`February 10, 2005 (02.10.2005)
`
`(25) International Filing Language:
`
`(26) International Publication Language:
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`Japanese
`
`Japanese
`
`(30) Priority Data:
` Japanese Patent Application 2004-09194 March 26, 2004 (03.26.2004) JP
`
`(71) Applicant: SEIKO INSTRUMENTS INC. [JP/JP]; 1-8 Nak-
`ase, Mihama-ku, Chiba-shi, Chiba 2618507 (JP).
`(54) TITLE OF THE INVENTION: BIOLOGICAL INFORMATION MEASURING DEVICE
`
`
`
`/continued overleaf/
`
`
`
`(57) Abstract: A biological information measuring device comprising: a biological sensor part including: a main body; a
`protruding part formed so as to protrude from the lower surface of the main body; a fixing means for mounting the main
`body to an arm while directing the lower surface of the main body toward the living body surface side; a light-emitting part
`for emitting light toward the living body while in contact with the living body surface; a light-receiving part for receiving
`reflected light from the living body out of the light emitted by the light-emitting part and generating a biological
`
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`[continued overleaf]
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`1
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`APPLE 1007
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`(84) Designated States (unless otherwise indicated, for every
`kind of regional protection available): ARIPO (BW, GH,
`GM, KE, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG, ZM,
`ZW), Eurasia (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM),
`Europe (AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR,
`GB, GR, HU, IE, IS, IT, LT, LU, MC, NL, PL, PT, RO, SE,
`SI, SK, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ,
`GW, ML, MR, NE, SN, TD, TG).
`
`
`Attached Documentation
`— International Search Report
`
`For two-letter codes and other abbreviations, refer to the
`"Guidance Notes on Codes and Abbreviations" appearing
`at the beginning of each regular issue of the PCT Gazette.
`
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`(74) Agent: SHIGA, Masatake et al.; 2-3-1 Yaesu, Chuo-ku,
`Tokyo 1048453 (JP).
`
`(81) Designated States (unless otherwise indicated, for every
`kind of national protection available): AE, AG, AL, AM,
`AT, AU, AZ, BA, BB, BG, BR, BW, BY, BZ, CA, CH, CN,
`CO, CR, CU, CZ, DE, DK, DM, DZ, EC, EE, EG, ES, FI,
`GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, KE, KG, KP,
`KR, KZ, LC, LK, LR, LS, LT, LU, LV, MA, MD, MG, MK,
`MN, MW, MX, MZ, NA, NI, NO, NZ, OM, PG, PH, PL, PT,
`RO, RU, SC, SD, SE, SG, SK, SL, SM, SY, TJ, TM, TN, TR,
`TT, TZ, UA, UG, US, UZ, VC, VN, YU, ZA, ZM, ZW.
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`information signal corresponding to the amount of received light; and a contact detection means for detecting whether the
`light-emitting part and the light-receiving part are in contact with the living body surface; and a biological information de-
`tection part which is provided on the main body and detects biological information based on the biological information
`signal; wherein the biological sensor part is disposed on the lower surface of the protruding part. The biological infor-
`mation measuring device enhances adherence and can be worn for a long time without causing discomfort.
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`SPECIFICATION
`BIOLOGICAL INFORMATION MEASURING DEVICE
`TECHNICAL FIELD
`(0001)
`The present invention relates to a biological information measuring device capable of
`measuring biological information such as pulse rate while mounted to the wrist (arm).
`
`The present application claims priority based on Japanese Patent Application No. H2004-
`091942 filed on March 26, 2004, the content of which is incorporated herein.
`BACKGROUND ART
`(0002)
`In response to a growing interest in health management in recent years, various biological
`information measuring devices capable of measuring various biological information such as pulse
`rate while mounted to the wrist (arm) or the like have been provided (for example, see Patent Doc-
`ument 1).
`(0003) A biological information measuring device of this type which detects pulse rate, for example,
`emits light toward a living body while mounted to the wrist, receives reflected light (cid:3013) that is, a re-
`flected signal (cid:3013) from blood vessels with a pulse sensor or the like, extracts a pulse signal corre-
`sponding to the pulse from the reflected signal, and calculates the pulse rate. Since the pulse rate
`can be measured easily while mounted to the wrist, in particular, the device is easily used by the
`wearer.
`Patent Document 1: Japanese Unexamined Patent Application Publication No. 2001-78973
`(paragraph Nos. 0011-0031, FIGS. 1-7)
`PROBLEM TO BE SOLVED BY THE INVENTION
`(0004)
`The conventional biological information measuring devices described above are typically used
`while mounted to the wrist. However, the movement of the user causes muscles to move and
`changes the thickness (diameter) of the wrist, which leads to the risk that a gap may be formed be-
`tween the biological information measuring device and the living body surface. This diminishes
`adherence, which may prevent accurate biological information from being detected. Moreover,
`since the biological information measuring device is fixed to the wrist, the feeling of pressure on
`the wrist increases when attached by a band, for example, which makes it difficult to wear for long
`periods of time.
`(0005)
`The present invention was conceived in light of such circumstances, and an object thereof is to
`provide a biological information measuring device which enhances adherence and can be worn for
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`a long time without causing discomfort.
`MEANS FOR SOLVING THE PROBLEM
`(0006)
`The present invention provides the following means for solving the problem described above.
`(0007)
`The biological information measuring device comprises: a biological sensor part including a
`main body, a protruding part formed so as to protrude from a lower surface of the main body, a
`fixing means for mounting the main body to an arm while directing the lower surface of the main
`body toward a living body surface side, a light-emitting part for emitting light toward the living
`body while in contact with the living body surface, a light-receiving part for receiving reflected
`light from the living body out of the light emitted by the light-emitting part and generating a bio-
`logical information signal corresponding to an amount of received light, and a contact detection
`means for detecting whether the light-emitting part and the light-receiving part are in contact with
`the living body surface; and a biological information detection part which is provided on the main
`body and detects biological information based on the biological information signal; wherein the
`biological sensor part is disposed on a lower surface of the protruding part.
`(0008)
`In the biological information measuring device according to this invention, light is emitted
`toward the living body from the light-emitting part after the main body is mounted to the wrist
`(arm) with the fixing means. A portion of the emitted light is absorbed, for example, by hemoglo-
`bin in blood vessels, and another portion of the light is reflected by biological tissue. The light-
`receiving part receives this reflected light and generates a biological information signal such as a
`pulse signal corresponding to the amount of received light. The biological information detection
`means then performs prescribed processing on the biological information signal so that biological
`information such as pulse rate can be detected. In addition, the contact detection means can detect
`whether the light-emitting part and the light-receiving part are indeed in contact with the living
`body surface.
`(0009)
`In particular, when the main body is mounted to the wrist by the fixing means, the protruding
`part protrudes from the lower surface of the main body, which facilitates contact between the living
`body surface and the lower surface of the protruding part. That is, the adherence of the biological
`sensor part is enhanced. Therefore, unlike in conventional configurations, it is unnecessary to fix
`the main body so as to strongly press (so as to compress) the main body against the living body
`surface with the fixing part. Accordingly, the device does not cause discomfort, even when worn
`for a long time. Moreover, since the adherence of the biological sensor part is enhanced, the light-
`emitting part and the light-receiving part can emit and receive light efficiently. Therefore, biologi-
`cal information can be detected with high precision.
`(0010)
`In addition, the biological information measuring device according to the present invention is
`configured so that, in the biological information measuring device of the present invention de-
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`scribed above, ridged parts are formed so as to protrude from the lower surface of the main body at
`positions a prescribed distance from side surfaces of the protruding part so as to sandwich at least
`the protruding part; and a distance between a lower surface of each ridged part and the lower sur-
`face of the main body part is set to be equal to or greater than a distance between the lower surface
`of the protruding part and the lower surface of the main body part.
`(0011)
`In the biological information measuring device according to this invention, when the main
`body is mounted to the arm with the fixing means, the living body surface is in contact with the
`lower surfaces of the ridged parts and the lower surface of the protruding part. At this time, the
`ridged parts protrude at positions a prescribed distance from the side surfaces of the protruding part
`so as to sandwich the protruding part, so gaps are formed between the protruding part and the
`ridged parts. As a result, the living body is in contact with the lower surfaces of the protruding part
`and the ridged parts while temporarily filling the gaps on both sides sandwiching the protruding
`part. Accordingly, the adherence between the living body surface and the biological sensor part can
`be secured more reliably.
`(0012)
`In particular, since the ridged parts protrude from the lower surface of the main body by a
`height equal to or greater than that of the protruding part, they come into contact with the living
`body surface simultaneously with or before the protruding part. As a result, the living body surface
`can be stably brought into contact with the lower surface of the protruding part in the same state,
`and the contact pressure can be made constant. Accordingly, biological information can be detected
`stably over a long period of time.
`(0013)
`In addition, the biological information measuring device according to the present invention is
`configured so that, in the biological information measuring device of the present invention de-
`scribed above, the contact detection part includes at least a pair of electrodes and detects whether
`the light-emitting part and the light-receiving part are in contact with the living body surface based
`on a potential difference between the pair of electrodes.
`(0014)
`In the biological information measuring device according to this invention, when the main
`body is mounted to the arm, the pair of electrodes come into contact with the living body surface so
`that a discharge occurs through the living body surface. As a result, the potential between the elec-
`trodes decreases. By detecting the potential difference between the pair of electrodes, it can be easi-
`ly and reliably detected whether the light-emitting part and the light-receiving part are indeed in
`contact with the living body surface. Note that the electrodes need not be a pair, and a plurality of
`electrodes, for example, may be provided so that contact can be detected based on the potential dif-
`ference between each of the electrodes.
`(0015)
`In addition, the biological information measuring device according to the present invention is
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`configured so that, in the biological information measuring device of the present invention de-
`scribed above, the pair of electrodes are disposed so as to sandwich the light-emitting part and the
`light-receiving part therebetween.
`(0016)
`In the biological information measuring device according to this invention, the pair of
`electrodes are disposed so as to sandwich the light-emitting part and the light-receiving part, so it
`can be detected whether the light-emitting part and the light-receiving part are in contact with the
`living body surface with high precision.
`(0017)
`In addition, the biological information measuring device according to the present invention is
`configured so that, in the biological information measuring device of the present invention de-
`scribed above, a flexible board which electrically connects the light-emitting part and the light-
`receiving part to the biological information detection part is provided; and the flexible board is
`provided inside the main body so as to push the light-emitting part and the light-receiving part to-
`ward the lower surface side of the main body with its own elasticity.
`(0018)
`In the biological information measuring device according to this invention, the light-emitting
`part and the light-receiving part are always pressed toward the lower surface side of the main body
`by the elasticity of the flexible board, so when the main body is mounted to the wrist, the light-
`emitting part and the light-receiving part are in close proximity to the living body surface. Accord-
`ingly, it is possible to emit light to and receive light from the living body efficiently, and the detec-
`tion precision for biological information can be enhanced.
`(0019)
`In addition, the biological information measuring device according to the present invention is
`configured so that, in the biological information measuring device of the present invention de-
`scribed above, a display part for displaying detected biological information is provided on an up-
`per surface of the main body.
`(0020)
`In the biological information measuring device according to this invention, biological
`information displayed on the display part can be easily viewed, so it is possible to confirm detected
`biological information or to confirm whether biological information has been detected properly at
`any time when necessary, which is use-friendly and convenient.
`(0021)
`In addition, the biological information measuring device according to the present invention is
`configured so that, in the biological information measuring device of the present invention de-
`scribed above, the fixing means includes first and second bands having base end sides attached to
`the main body to enable mounting on the arm; and the first and second bands are disposed opposite
`one another so as to sandwich the main body and are formed from an expandable elastic material.
`(0022)
`In the biological information measuring device according to this invention, the main body can
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`be easily and reliably mounted like a wristwatch using the first and second bands. In particular,
`since both bands are formed from an expandable elastic material, even if the thickness of the wrist
`changes somewhat due to muscle movement, the amount of change can be absorbed, and gaps or
`the like can be prevented from forming between the main body and the living body surface. As a
`result, it is unnecessary to tighten both bands, and the device can be worn for a long time.
`(0023)
`In addition, the biological information measuring device according to the present invention is
`configured so that, in the biological information measuring device of the present invention de-
`scribed above, the biological sensor part is disposed at a position offset toward the base end side of
`the first or second band from a center position of the main body.
`(0024)
`In the biological information measuring device according to this invention, when the main
`body is mounted to the wrist like a wristwatch using the first and second bands, even if there is
`small amount of play relative to the wrist and the main body shifts due to the gravitational effect as
`a result of this play (for example, when the main body shifts in a state in which the arm is facing
`downward (ground side) or when the main body shifts in a state in which the back of the hand is on
`the inside while the arm is positioned horizontally and the upper surface of the main body is held in
`front of the eyes), the biological sensor part is disposed at a position offset toward the base end side
`of the first or second band from the center position of the main body, so it is possible to prevent a
`reduction in the adherence of the biological sensor part.
`(0025)
`In addition, the biological information measuring device according to the present invention is
`configured so that, in the biological information measuring device of the present invention de-
`scribed above, a rechargeable battery that can be recharged and a recharging means for recharging
`the rechargeable battery with power are provided on the main body.
`(0026)
`In the biological information measuring device according to this invention, the rechargeable
`battery can be recharged with power from an external source via the recharging means, so it is un-
`necessary to separately prepare an ordinary battery or the like. Accordingly, the cost of maintaining
`the product can be reduced.
`(0027)
`In addition, the biological information measuring device according to the present invention is
`configured so that, in the biological information measuring device of the present invention de-
`scribed above, a distance between the lower surface of the protruding part and the lower surface of
`the main body is set to 2 to 4 mm.
`(0028)
`The biological information measuring device according to this invention is mounted to the
`wrist while the lower surface of the protruding part protrudes 2 to 4 mm from the lower surface of
`the main body. As a result, the protruding part can be reliably brought into contact with the living
`body surface, and the adherence of the biological sensor part can be ensured. That is, when the dis-
`tance between the lower surface of the protruding part and the lower surface of the main body is
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`2 mm or smaller, the level difference is small, and a gap is formed relative to the living body
`surface so that external light can enter easily. In addition, when the distance between the lower sur-
`face of the protruding part and the lower surface of the main body is 4 mm or greater, an oppres-
`sive feeling arises when the device is worn, while the height causes instability, and external light
`can easily enter the space between the device and the living body surface when inclined.
`(0029) As described above, setting the distance between the lower surface of the protruding part and
`the lower surface of the main body to 2 to 4 mm makes it possible to prevent an oppressive feeling
`and the incidence of external light.
`(0030)
`In addition, the biological information measuring device according to the present invention is
`configured so that, in the biological information measuring device of the present invention de-
`scribed above, the protruding part is formed so that an outer periphery thereof is circular.
`(0031)
`In the biological information measuring device according to this invention, In the biological
`information measuring device according to this invention, the protruding part is circular, so when
`the main body is mounted to the wrist, it is pressed against the living body surface with equal force.
`Therefore, the adherence is good.
`(0032)
`In addition, the biological information measuring device according to the present invention is
`configured so that, in the biological information measuring device of the present invention de-
`scribed above, the protruding part is formed so that an outer edge thereof is a curved surface.
`(0033)
`In the biological information measuring device according to this invention, the outer edge of
`the protruding part is formed with a curved surface, so when the main body is mounted to the wrist,
`the adherence can be enhanced even further. Moreover, even when worn for a long time, pressure
`marks are unlikely to form, so the device is comfortable to wear.
`(0034)
`In addition, the biological information measuring device according to the present invention is
`configured so that, in the biological information measuring device of the present invention de-
`scribed above, the protruding part is formed with a curved surface from a center toward an outer
`edge of the lower surface thereof.
`(0035)
`In the biological information measuring device according to this invention, the protruding part
`is formed with a curved surface from the center toward the outer edge of the lower surface thereof,
`so when the main body is mounted to the wrist, it is mounted in a state in which the living body
`surface deforms smoothly and the contact pressure of the center part of the lower surface is in-
`creased, which further enhances the adherence. Moreover, even when worn for a long time, pres-
`sure marks are unlikely to form, so the device is comfortable to wear.
`(0036)
`In addition, the biological information measuring device according to the present invention is
`configured so that, in the biological information measuring device of the present invention de-
`scribed above, a diameter of the protruding part is set to not greater than 20 mm.
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`In the biological information measuring device according to this invention, the diameter of the
`(0037)
`protruding part is not greater than 20 mm, so the protruding part can be easily pressed against the
`living body surface with a light force.
`(0038)
`In addition, the biological information measuring device according to the present invention is
`configured so that, in the biological information measuring device of the present invention de-
`scribed above, the ridged parts are provided at a position 8 mm from side surfaces of the protruding
`part, and a distance between the lower surface of each ridged part and the lower surface of the main
`body is set to 4 mm.
`(0039)
`In the biological information measuring device according to this invention, the ridged parts can
`be formed in close proximity of 8 mm from the side surfaces of the protruding part and can be kept
`to a height of 4 mm. Thus, the ridged parts can be formed in a small space, so the size of the main
`body can be reduced (cid:3013) that is, the size of the entire device can be reduced.
`EFFECT OF THE INVENTION
`(0040) According to the biological information measuring device according to the present invention,
`when the main body is mounted to the wrist with the fixing part, the protruding part protrudes from
`the lower surface of the main body, so the living body surface and the lower surface of the protrud-
`ing part come into contact reliably, which enhances the adherence of the biological sensor part.
`Therefore, unlike in conventional configurations, it is unnecessary to fix the main body so as to
`strongly press (so as to compress) the main body against the living body surface with the fixing
`part. Accordingly, the device does not cause discomfort, even when worn for a long time. Moreo-
`ver, since the adherence of the biological sensor part is enhanced, light can be emitted and received
`efficiently, and biological information can be detected with high precision.
`BRIEF DESCRIPTION OF THE DRAWINGS
`(0041) FIG. 1 is a front view illustrating an embodiment of the biological information measuring device
`according to the present invention.
`FIG. 2 is a side view illustrating a state in which the biological information measuring device
`illustrated in FIG. 1 is mounted to the wrist.
`FIG. 3 is a side view illustrating a state in which the biological information measuring device
`illustrated in FIG. 1 is mounted to the wrist, and is a view from the opposite direction as that illus-
`trated in FIG. 2.
`FIG. 4 is a perspective view illustrating a state in which the biological information measuring
`device illustrated in FIG. 1 is viewed diagonally from above.
`FIG. 5 is a perspective view illustrating a state in which the biological information measuring
`device illustrated in FIG. 1 is viewed diagonally from below.
`FIG. 6 is a cross-sectional view of the biological information measuring device illustrated in FIG. 4
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`along arrows C-C.
`FIG. 7 is a cross-sectional view of the biological information measuring device illustrated in FIG. 4
`along arrows D-D.
`FIG. 8 is a drawing illustrating the shape of another protruding part than that of the biological
`information measuring device illustrated in FIG. 1, and is a drawing of a case in which the outer
`periphery of the protruding part is circular.
`FIG. 9 is a drawing of a case in which the protruding part illustrated in FIG. 8 is formed so that the
`outer edge thereof is a curved surface.
`FIG. 10 is a drawing of a case in which the protruding part illustrated in FIG. 8 is formed with a
`curved surface from the center toward the outer edge of the lower surface thereof.
`FIG. 11 is a drawing of a case in which the ridged parts are formed so as to sandwich the
`protruding part illustrated in FIG. 8.
`FIG. 12 is a drawing of a case in which the ridged parts are formed so as to sandwich the
`protruding part illustrated in FIG. 9.
`FIG. 13 is a drawing of a case in which the ridged parts are formed so as to sandwich the
`protruding part illustrated in FIG. 10.
`EXPLANATION OF SYMBOLS
`(0042)
`B: Living body surface, 1: biological information measuring device, 2: housing (main body),
`2a: lower surface of main body, 2b: upper surface of main body, 3: fixing means, 4: protruding part,
`4a: lower surface of protruding part, 4b: side surface of protruding part, 5: LED (light-emitting
`part), 6: PD (light-receiving part), 7: contact detection means, 7a, 7b: pair of electrodes, 8: biologi-
`cal sensor part, 9: data processing part (biological information detection part), 11: display part, 13:
`rechargeable battery, 21: external connection terminal (recharging means), 24: flexible board, 30:
`first band, 31: second band, 40: ridged part, 40a: lower surface of ridged part
`BEST MODE FOR CARRYING OUT THE INVENTION
`(0043) An embodiment of the biological information measuring device according to the present
`invention will be described hereinafter with reference to FIGS. 1 to 7.
`(0044) As illustrated in FIGS. 1 to 7, a biological information measuring device 1 of this embodiment
`is a wristwatch-type device which detects pulse rate as a type of biological information while
`mounted to the wrist (arm) A.
`(0045)
`This biological information measuring device 1 includes a housing (main body) 2 internally
`equipped with various electrical parts and electronic parts, and a fixing means 3 for mounting the
`housing 2 to the wrist A while directing the lower surface 2a of the housing 2 toward a surface B
`side of a living body. In addition, a protruding part 4 which protrudes from the lower surface 2a is
`formed on the lower surface 2a of the housing 2.
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`(0046) A biological sensor part 8, which includes an LED (Light Emitting Diode) (light-emitting part)
`5 for emitting light toward the living body while in contact with the living body surface B side, a
`PD (Photodetector) (light-receiving part) 6 for receiving reflected light from the living body out of
`the light emitted by the LED 5 and generating a pulse signal (biological information signal) corre-
`sponding to the amount of received light, and a contact detection means 7 for detecting whether the
`LED 5 and the PD 6 are in contact with the living body surface B, is disposed on the lower surface
`4a of the protruding part 4.
`(0047)
`In addition, a data processing part (biological information detection part) 9 for detecting pulse
`rate based on the generated pulse signal is provided inside the housing 2.
`(0048)
`The housing 2 described above is made of plastic or a metal material such as aluminum and is
`formed with a prescribed thickness into a substantially rectangular shape from a top view, for ex-
`ample. A cover glass 10 with a substantially square shape is fitted into the central portion of the
`upper surface 2b of the housing 2, and a display part 11 for displaying the aforementioned pulse
`rate that is detected and various other information is disposed inside the cover glass 10.
`(0049)
`In addition, as illustrated in FIGS. 6 and 7, a main board 12 is provided inside the housing 2,
`and the data processing part 9, the display part 11, a rechargeable battery 13 that can be recharged,
`a memory 14 for recording the pulse rate, a sub-board 15, and various other electronic parts are
`mounted on or electrically connected to the main board 12.
`(0050)
`The data processing part 9 includes IC parts such as a CPU, and has a function of detecting the
`pulse rate by temporarily amplifying the pulse signal generated by the PD6 with an amplifier, per-
`forming prescribed processing such as Fast Fourier Transform processing (FFT processing), and
`then analyzing the processing results. In addition, the data processing part 9 records the detected
`pulse rate in the memory 14 and displays the pulse rate on the display part 11 based on input from
`each button 20 described below. Further, the data processing part 9 has a function of comprehen-
`sively controlling other components.
`(0051)
`The display part 11 is a liquid crystal display device such as an LCD (Liquid Crystal Display),
`for example, and in addition to the pulse rate described above, it has a time display function for
`displaying the time counted by a crystal resonator (not illustrated), for example, or a function of
`displaying various other information. For example, the time, date, day of the week, the remaining
`power of the rechargeable battery 13, or the like can be displayed.
`(0052)
`In addition, as illustrated in FIGS. 1 and 2, various buttons 20 such as three buttons 20
`disposed on the upper surface 2b of the housing 2 and below the display part 11 and one button 2
`disposed on the side surface of the housing 2, for example, are provided on the housing 2. Various
`
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`11
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`

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`WO 2005/092182
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`10
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`PCT/JP2005/002021
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`
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`operations can be performed by pressing each of these buttons 20. Operations such as starting or
`stopping the measurement of the pulse rate, switching the display between the pulse rate and time,
`and sending pulse rate data recorded in the memory 14 to an external device, for example, can be
`performed.
`(0053)
`Further, an external connection terminal (recharging means) 21 for recharging the rechargeable
`battery 13 by supplying power from an external device such as a recharger is provided on the side
`surface of the housing 2. Note that the external connection terminal 21 may be protected by attach-
`ing a cover or the like so as to cover the external connection terminal 21. This makes it possible to
`protect the external connection terminal 21 from water droplets, dust, or the like, which is more
`preferable. In addition, rather than the external connection terminal 21, a transformer or the like for
`supplying power to a recharger and to the inside of the housing 2 may be provided so as to recharge
`the rechargeable battery 13 in