(19) Japan Patent Office (JP)
`
`(12) JAPANESE UNEXAMINED PATENT
`APPLICATION PUBLICATION (A)
`
`(11) Patent Application
`Publication No.
`JP 2005-270543
`(P2005-270543A)
`(43) Publication Date: October 6, 2005 (Heisei 17)
`Theme Code (Reference)
`4C017
`
`(51) Int. Cl.7
`A61B
`
`5/0245
`
`FI
`
`A61B 5/02 320B
`
`(Total 17 pages)
`
`Examination Request: Not Yet
`(21) Application No.
`JP 2004-91942
`(P2004-91942)
`March 26, 2004
` (Heisei 16)
`
`(22) Date of Filing
`
`(Patent Office Note: The following is a registered
`trademark)
`1. Bluetooth
`
`(74) Agent
`
`(72) Inventor
`
`(72) Inventor
`
`(72) Inventor
`
`Total No. of Claims: 15 OL
`(71) Applicant
`000002325
`Seiko Instruments, Inc.
`1-8 Nakase, Mihama-ku,
`Chiba-shi, Chiba-ken
`100079212
`Yoshiharu Matsushita,
` Patent Attorney
`Susumu Otanagi
`c/o Seiko Instruments, Inc.
`1-8 Nakase, Mihama-ku,
`Chiba-shi, Chiba-ken
`Takashi Nakamura
`c/o Seiko Instruments, Inc.
`1-8 Nakase, Mihama-ku,
`Chiba-shi, Chiba-ken
`Kazuya Maekawa
`c/o Seiko Instruments, Inc.
`1-8 Nakase, Mihama-ku,
`Chiba-shi, Chiba-ken
`Continued on last page
`(54) [Title of Invention] BIOLOGICAL INFORMATION MEASURING DEVICE
`
`(57) [Abstract]
`[Problem] To improve adhesion and wear for a long time without
`experiencing a feeling of discomfort.
`[Resolution Means] To provide a biological information measuring
`device 1, provided with: a main body 2; a projection part 4 formed by
`projecting from a lower surface 2a of the main body 2; fixing means 3
`for wearing the main body 2 on an arm in a state wherein the lower
`surface 2a of the main body 2 is directed to a biological body surface
`side; a biological sensor part 8 having a light emitting part 5 for
`irradiating light directed to a biological body when in a state contacting
`the biological body surface, a light receiving part 6 for receiving
`reflected light from the biological body from among light irradiated by
`the light emitting part 5 and for generating a biological information
`signal corresponding to the received light quantity, and contact sensing
`means 7 for sensing whether the light emitting part 5 and the light
`receiving part 6 are contacting the biological body surface; and a
`biological information sensing part for sensing biological information
`based on the biological information signal and provided on the main
`body 2; wherein the biological sensor part 8 is disposed on a lower
`surface 4a of the projection part 4.
`[Selected Drawing] FIG. 5
`
`1
`
`APPLE 1043
`
`

`

`2
`
`JP 2005-270543 A (P2005-270543A)
`
`[Scope of Patent Claims]
`[Claim 1]
`A biological information measuring device, comprising:
`a main body;
`a projection part formed by projecting from a lower surface of the main body;
`fixing means for wearing the main body on an arm in a state wherein the lower surface of
`the main body is directed to a biological body surface side;
`a biological sensor part having a light emitting part for irradiating light directed to a
`biological body when in a state contacting the biological body surface, a light receiving part for
`receiving reflected light from the biological body from among light irradiated by the light emitting
`part and for generating a biological information signal corresponding to the received light quantity,
`and contact sensing means for sensing whether the light emitting part and the light receiving part are
`contacting the biological body; and
`a biological information sensing part provided on the main body for sensing biological
`information based on the biological information signal; wherein:
`the biological sensor part is disposed on a lower surface of the projection part.
`[Claim 2]
`The biological information measuring device according to claim 1, wherein:
`a convex part is provided at the lower surface of the main body, formed to interpose at least
`the projection part and project from the lower surface of the main body at a position separated by a
`predetermined distance from the side surface of the projection part, and
`the distance between the lower surface of the convex part and the lower surface of the main
`body part is set to be the same as or greater than the distance between the lower surface of the
`projection part and the lower surface of the main body part.
`[Claim 3]
`The biological information measuring device according to claims 1 or 2, wherein:
`the contact sensing means has at least one pair of electrodes and senses whether the light
`emitting part and the light receiving part are contacting the biological body surface based on the
`potential difference between the pair of electrodes.
`[Claim 4]
`The biological information measuring device according to claim 3, wherein:
`the pair of electrodes is disposed so as to interpose between the light emitting part and the
`light receiving part.
`[Claim 5]
`The biological information measuring device according to any one of claims 1 to 4, further
`comprising:
`a flexible substrate electrically connecting between the biological information sensing part
`and the light emitting part and the light receiving part, wherein:
`the flexible substrate is provided in the main body so as to use its own elasticity to press the
`light emitting part and the light receiving part directed to the lower surface side of the main body.
`[Claim 6]
`The biological information measuring device according to any one of claims 1 to 5, further
`comprising:
`a display part for displaying sensed biological information on the upper surface of the main
`body.
`[Claim 7]
`The biological information measuring device according to any one of claims 1 to 6, wherein:
`the fixing means comprises a first band and a second band which are attached to the main body by
`the base end side and may be worn on an arm, wherein:
`the first band and the second band are disposed to interpose and face the main body and are
`formed of a stretchable elastic material.
`[Claim 8]
`The biological information measuring device according to claim 7, wherein:
`the biological sensor part is disposed at a position shifted from the center position of the
`main body to the base end side of the first band or the second band.
`
`2
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`JP 2005-270543 A (P2005-270543A)
`3
`[Claim 9]
`The biological information measuring device according to any one of claims 1 to 8, further
`comprising:
`a rechargeable battery capable of being charge and charging means for charging power to
`the rechargeable battery, on the main body.
`[Claim 10]
`The biological information measuring device according to any one of claims 1 to 9, wherein:
`the distance between the lower surface of the projection part and the lower surface of the
`main body is set to 2 to 4 mm.
`[Claim 11]
`The biological information measuring device according to any one of claims 1 to 10,
`wherein:
`the projection part is formed so that the outer circumference is circular.
`[Claim 12]
`The biological information measuring device according to claim 11, wherein:
`the projection part is formed so that the outer edge is a curved surface.
`[Claim 13]
`The biological information measuring device according to claim 11, wherein:
`the projection part is formed so as to form a curved surface directed from the center of the
`lower surface to the outer edge.
`[Claim 14]
`The biological information measuring device according to any one of claims 11 to 13,
`wherein:
`the diameter of the projection part is set to 20 mm or less.
`[Claim 15]
`The biological information measuring device according to any one of claims 2 to 14,
`wherein:
`the convex part is provided at a position separated by 8 mm from the side surface of the
`projection part, and the distance between the lower surface of the projection part and the lower
`surface of the main body is set to 4 mm.
`[Detailed Description of Invention]
`[Technical Field]
`[0001]
`The present invention relates to a biological information measuring device capable of
`measuring biological information such as pulse rate when in a state of being worn on a wrist (arm).
`[Background Art]
`[0002]
`As interest in health management has increased in recent years, many kinds of biological
`information measuring devices have been provided, capable of measuring various biological
`information such as pulse rate while worn on a wrist (arm) or the like (for example, see Patent
`Literature 1).
`[0003]
`Among the biological information measuring devices of this kind, for example, one that
`senses the pulse rate, when in a state when worn on a wrist, irradiates light to a biological body, uses
`a pulse sensor or the like to receive reflected light — that is, to receive a reflected signal — from
`blood vessels, extracts a pulse signal corresponding to the pulse from the reflected signal, and
`calculates the pulse rate. In particular, this is easily used by a user since measurement of the pulse
`rate may be easily performed while worn on a wrist.
`[Patent Literature 1]JP 2001-78973 A (paragraph numbers 0011 to 0031 and FIG. 1 to FIG. 7)
`[Disclosure of Invention]
`[Problem to Be Solved by Invention]
`[0004]
`
`3
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`

`JP 2005-270543 A (P2005-270543A)
`4
`The conventional biological information measuring device described above is generally used while worn on a
`wrist. However, depending on the movement of a user, when there is muscle movement the thickness (diameter) of the
`wrist ends up changing, and there is a risk that a gap will open between the biological information measuring device and
`the biological body surface. Therefore, there is a possibility that adhesion will reduce and accurate biological information
`cannot be sensed. Furthermore, in order to securely fix the biological information measuring device to a wrist, in the case
`of fastening with a band for example, a feeling of pressure on the wrist increases and it is difficult to wear the device for
`a long time.
`[0005]
`
`The present invention was created in consideration of such circumstances, and thus an object thereof is to
`provide a biological information measuring device with improved adhesion and that may be worn for a long time without
`experiencing a feeling of discomfort.
`[Means for Solving Problem]
`[0006]
`
`The present invention provides the following means for solving the problem.
`
`[0007]
`
`A biological information measuring device of the present invention is provided with a main body; a projection
`part formed by projecting from a lower surface of the main body; fixing means for wearing the main body on an arm in a
`state wherein the lower surface of the main body is directed to a biological body surface side; a biological sensor part
`having a light emitting part for irradiating light directed to a biological body when in a state contacting the biological
`body surface, a light receiving part for receiving reflected light from the biological body from among light irradiated by
`the light emitting part and for generating a biological information signal corresponding to the received light quantity, and
`contact sensing means for sensing whether the light emitting part and the light receiving part are contacting the biological
`body; and a biological information sensing part provided on the main body for sensing biological information based on
`the biological information signal; wherein the biological sensor part is disposed on a lower surface of the projection part.
`[0008]
`
`In the biological information measuring device of this invention, after the main body is worn on a wrist (arm)
`using the fixing means, light is irradiated from the light emitting part directed to the biological body. A part of the
`irradiated light is absorbed by, for example, hemoglobin or the like in blood vessels, and furthermore, another part of the
`light is reflected by biological tissue. The light receiving part receives the reflected light and generates a biological
`information signal, such as a pulse signal corresponding to the received light quantity. Also, biological information
`sensing means makes it possible to perform sensing of biological information, such as pulse rate, by carrying out
`predetermined processing of the biological information signal. Furthermore, the contact sensing means makes it possible
`to perform sensing as to whether the light emitting part and the light receiving part are securely contacting the biological
`body surface.
`[0009]
`
`In particular, when the main body is worn on a wrist using the fixing means, since the projection part projects
`from the lower surface of the main body, a state is formed wherein the biological body surface and the lower surface of
`the projection part are easily brought into contact. That is, the adhesion of the biological sensor part is improved.
`Therefore, it is not necessary to use the fixing means to strongly press (apply pressure to) the main body against the
`biological body surface as is conventional. Accordingly, even if it is worn for a long time, a feeling of discomfort is not
`experienced. Furthermore, since the adhesion of the biological sensor part is improved, the light emitting part and the
`light receiving part are capable of efficiently irradiating and receiving light. Accordingly, sensing of the biological
`information may be performed with high accuracy.
`[0010]
`
`Furthermore, as for the biological information measuring device of the present invention, in the biological
`information measuring device of the foregoing present invention, a convex part is provided at the lower surface of the
`main body, formed to interpose at least the projection part and project from the lower surface of the main body at a
`position separated by a predetermined distance from the side surface of the projection part, and the distance between the
`lower surface of the convex part and the lower surface of the main body part is set to be the same as or greater than the
`distance between the lower surface of the projection part and the lower surface of the main body part.
`[0011]
`In the biological information measuring device of this invention, when the main body is worn on an arm using
`the fixing means, a state is formed wherein the biological body surface is contacting the lower surface of the
`
`4
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`

`JP 2005-270543 A (P2005-270543A)
`5
`convex part and the lower surface of the projection part. At this time, since the convex part interposes the projection part
`and projects at a position separated by a predetermined distance from the side surface of the projection part, a state is
`formed wherein a gap opens between the convex part and the projection part. As a result, the biological body contacts the
`lower surfaces of the convex part and the projection part when in a state of temporarily entering the gaps on both sides
`interposing the projection part. Accordingly, adhesion between the biological body surface and the biological sensor part
`may be more securely maintained.
`[0012]
`
`In particular, since the convex part projects from the lower surface of the main body with respect to the
`projection part by the same height or a greater height, the convex part contacts the biological body surface in the same
`manner as the projection part or ahead of the projection part. Furthermore, the convex part contacts the biological body
`surface on an outer side of the projection part. As a result, the biological body surface may be brought into contact with
`the lower surface of the projection part in the same state and in a stable manner, and contact pressure may be made
`constant. Accordingly, biological information may be sensed for a long time in a stable manner.
`[0013]
`
`Furthermore, as for the biological information measuring device of the present invention, in the biological
`information measuring device of the foregoing present invention, the contact sensing means has at least one pair of
`electrodes and senses whether the light emitting part and the light receiving part are contacting the biological body
`surface based on the potential difference between the pair of electrodes.
`[0014]
`
`In the biological information measuring device of this invention, when the main body is worn on an arm, the
`pair of electrodes contact the biological body surface and discharge is performed through the biological body surface. As
`a result, potential between the electrodes is reduced. Also, by sensing the potential difference between the pair of
`electrodes, it is possible to easily and reliably sense whether the light emitting part and the light receiving part are
`securely contacting the biological body surface. Note that the electrodes may not be a pair; for example, a plurality of
`electrodes may be provided, and whether contact is being made may be sensed based on the potential difference of these
`respective electrodes.
`[0015]
`
`Furthermore, as for the biological information measuring device of the present invention, in the biological
`information measuring device of the foregoing present invention, the pair of electrodes is disposed so as to interpose
`between the light emitting part and the light receiving part.
`[0016]
`
`In the biological information measuring device of this invention, since the pair of electrodes is disposed so as to
`interpose between the light emitting part and the light receiving part, it is possible to sense whether the light emitting part
`and the light receiving part are contacting the biological body surface with high accuracy.
`[0017]
`
`Furthermore, the biological information measuring device of the present invention, in the biological
`information measuring device of any one of the foregoing present inventions, is provided with a flexible substrate
`electrically connecting between the biological information sensing part and the light emitting part and the light receiving
`part, wherein the flexible substrate is provided in the main body so as to use its own elasticity to press the light emitting
`part and the light receiving part directed to the lower surface side of the main body.
`[0018]
`
`In the biological information measuring device of this invention, since the light emitting part and the light
`receiving part are always pressed to the lower surface side of the main body by the elasticity of the flexible substrate,
`when the main body is worn on a wrist, a state is formed wherein the light emitting part and the light receiving part are
`brought close to the biological body surface. Accordingly, irradiation and receiving of light may be performed more
`efficiently with respect to the biological body, and sensing accuracy of biological information may be improved.
`[0019]
`
`Furthermore, the biological information measuring device of the present invention, in the biological
`information measuring device according to any one of the foregoing present inventions, is provided with a display part
`for displaying sensed biological information on the upper surface of the main body.
`[0020]
`
`In the biological information measuring device of this invention, since the biological information displayed on
`the display part is easily visible, it is possible to check the sensed biological information whenever necessary, and to
`check whether the biological information is being correctly sensed, or the like, and thus it is easy and simple to use.
`[0021]
`
`Furthermore, as for the biological information measuring device of the present invention, in the biological
`information measuring device of any one of the foregoing present inventions, the fixing means is provided with a first
`band and a second band which are attached to the main body by the base end side and may be worn on an arm,
`
`5
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`

`

`JP 2005-270543 A (P2005-270543A)
`6
`wherein the first band and the second band are disposed to interpose and face the main body and are formed of a
`stretchable elastic material.
`[0022]
`
`In the biological information measuring device of this invention, the main body may be easily and reliably
`worn on a wrist like a wristwatch using the first band and the second band. In particular, since both bands are formed of a
`stretchable elastic material, when the thickness of the wrist changes somewhat due to muscle movement, the amount of
`change thereof may be absorbed, and generation of a gap or the like between the main body and the biological body
`surface may be prevented. Therefore, it is not necessary to fasten both bands, and the device may be worn for a long
`time.
`[0023]
`
`Furthermore, as for the biological information measuring device of the present invention, in the biological
`information measuring device of any one of the foregoing present inventions, the biological sensor part is disposed at a
`position shifted from the center position of the main body to the base end side of the first band or the second band.
`[0024]
`
`In the biological information measuring device of this invention, when the main body is worn on a wrist like a
`wristwatch using the first band and the second band, even if there is slight play between the wrist and the main body is
`shifted by gravitational action due to this play (for example, when in a state wherein the arm is shifted facing downward
`(ground side), when in a state wherein the back of the hand is positioned to the inner side, the arm is positioned
`horizontally, and the upper surface of the main body is held in front of the eyes, or the like), since the biological sensor
`part is disposed at a position shifted from the center position of the main body to the base end side of the first band or the
`second band, a decrease in the adhesion of the biological sensor part may be prevented.
`[0025]
`
`Furthermore, the biological information measuring device of the present invention, in the biological
`information measuring device of any one of the foregoing present inventions, is further provided with a rechargeable
`battery capable of being charged and charging means for charging power to the rechargeable battery, on the main body.
`[0026]
`
`In the biological information measuring device of this invention, since external power may be charged to the
`rechargeable battery via the charging means, it is not necessary to separately provide a regular battery or the like.
`Accordingly, costs relating to the maintenance of the product may be reduced.
`[0027]
`
`Furthermore, as for the biological information measuring device of the present invention, in the biological
`information measuring device of any one of the foregoing present inventions, the distance between the lower surface of
`the projection part and the lower surface of the main body is set to 2 to 4 mm.
`[0028]
`
`In the biological information measuring device of this invention, the lower surface of the projection part is worn
`on a wrist in a state projecting 2 to 4 mm from the lower surface of the main body. As a result, the projection part may be
`securely brought into contact with the biological body surface, and the adhesion of the biological sensor part may be
`maintained. In other words, when the distance between the lower surface of the projection part and the lower surface of
`the main body is 2 mm or less, the difference in level is reduced, a gap may be formed between the biological body
`surface, and external light easily enters. Furthermore, when the distance between the lower surface of the projection part
`and the lower surface of the main body is 4 mm or more, a feeling of pressure is generated during wear and there is also
`height; therefore, an unstable state forms, and, for example, external light easily enters between the biological body
`surface when tilted.
`[0029]
`
`As described above, by making the distance between the lower surface of the projection part and the lower
`surface of the main body 2 to 4 mm, a feeling of pressure and incidence of external light may be prevented.
`[0030]
`
`Furthermore, as for the biological information measuring device of the present invention, in the biological
`information measuring device of any one of the foregoing present inventions, the projection part is formed so that the
`outer circumference is circular.
`[0031]
`
`
`
`6
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`

`JP 2005-270543 A (P2005-270543A)
`7
`In the biological information measuring device of this invention, since the projection part is circular, when the
`main body is worn on a wrist, it is pushed against the biological body surface with a uniform force. Accordingly, the
`adhesion is good.
`[0032]
`
`Furthermore, as for the biological information measuring device of the present invention, in the biological
`information measuring device of any one of the foregoing present inventions, the projection part is formed so that the
`outer edge is a curved surface.
`[0033]
`
`In the biological information measuring device of this invention, since the outer edge of the projection part is a
`curved surface, when the main body is worn on a wrist, it may be possible to further improve adhesion. Furthermore,
`even if worn for a long time, the device is easy to wear because it is difficult for pressure marks to be made.
`[0034]
`
`Furthermore, as for the biological information measuring device of the present invention, in the biological
`information measuring device of the foregoing present invention, the projection part is formed so as to form a curved
`surface directed from the center of the lower surface to the outer edge.
`[0035]
`
`In the biological information measuring device of this invention, since the projection part is formed on a curved
`surface directed from the center of the lower surface to the outer edge, when the main body is worn on a wrist, it is worn
`in a state wherein the biological body surface is smoothly deformed, and the contact pressure of the central portion of the
`lower surface is raised, so that it may be possible to further improve adhesion. Furthermore, even if worn for a long time,
`the device is easy to wear because it is difficult for pressure marks to be made.
`[0036]
`
`Furthermore, as for the biological information measuring device of the present invention, in the biological
`information measuring device of any one of the foregoing present inventions, the diameter of the projection part is set to
`20 mm or less.
`[0037]
`
`In the biological information measuring device of this invention, since the diameter of the projection part is 20
`mm or less, the projection part may be easily pressed against the biological body surface with light force.
`[0038]
`
`Furthermore, as for the biological information measuring device of the present invention, in the biological
`information measuring device of any one of the foregoing present inventions, the convex part is provided at a position
`separated by 8 mm from the side surface of the projection part, and the distance between the lower surface of the convex
`part and the lower surface of the main body is set to 4 mm.
`[0039]
`
`In the biological information measuring device of this invention, the convex part may be formed in the vicinity
`of 8 mm from the side surface of the projection part and may be kept to a height of 4 mm. Since the convex part may be
`formed in a small space in this manner, the main body may be miniaturized — that is, the entire device may be
`miniaturized.
`[Effect of Invention]
`[0040]
`
`According to the biological information measuring device of the present invention, when the main body is worn
`on a wrist using the fixing means, since the projection part projects from the lower surface of the main body, the
`biological body surface and the lower surface of the projection part are in secure contact and the adhesion of the
`biological sensor part is improved. Therefore, it is not necessary to use the fixing means to strongly press (apply pressure
`to) the main body against the biological body surface as is conventional. Accordingly, even if it is worn for a long time, a
`feeling of discomfort is not experienced. Furthermore, since the adhesion of the biological sensor part is improved,
`irradiation and receiving of light may be performed efficiently, and sensing of the biological information may be
`performed with high accuracy.
`[Best Mode for Carrying Out Invention]
`[0041]
`
`One embodiment of the biological information measuring device of the present invention is described
`below with reference to FIG.1 to FIG. 7.
`[0042]
`
`7
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`

`JP 2005-270543 A (P2005-270543A)
`8
`A biological information measuring device 1 of the present embodiment is, as illustrated in FIG. 1 to FIG. 7, a
`wristwatch-type, and senses a pulse rate, which is biological information, when in a state wherein it is worn on a wrist
`(arm).
`[0043]
`
`The biological information measuring device 1 is provided with a housing (main body) 2 containing various
`electric components and electronic components, and fixing means 3 for wearing the housing 2 on a wrist A when in a
`state wherein a lower surface 2a of the housing 2 is directed to a biological body surface B side. Furthermore, a
`projection part 4 projecting from the lower surface 2a is formed on the lower surface 2a of the housing 2.
`[0044]
`
`A biological sensor part 8 is disposed on a lower surface 4a of the projection part 4, and has an LED (light
`emitting part) 5 for irradiating light directed to a biological body when in a state contacting the biological body surface B
`side, a PD (photodetector) (light receiving part) 6 for receiving reflected light from the biological body from among light
`irradiated by the LED 5 and generating a pulse signal (biological information signal) corresponding to the received light
`quantity, and contact sensing means 7 for sensing whether the LED 5 and the PD 6 are contacting the biological body
`surface B.
`[0045]
`
`Furthermore, a data processing part (biological information sensing part) 9 for sensing the pulse rate based on
`the generated pulse signal is provided in the housing 2.
`[0046]
`
`The housing 2 is composed of plastic or a metal material such as aluminum, and is formed having a
`predetermined thickness and, for example, a substantially rectangular shape when viewed from the upper surface. A
`substantially square-shaped cover glass 10 is fitted to a center portion of an upper surface 2b of the housing 2, and a
`display part 11 for displaying the sensed pulse rate and various other information is disposed on an inner side of the
`cover glass 10.
`[0047]
`
`Furthermore, a main substrate 12 is provided in the housing 2 as illustrated in FIG. 6 and FIG. 7, and the data
`processing part 9, the display part 11, a rechargeable battery 13 capable of being charged, a memory 14 for recording a
`pulse rate, a sub-substrate 15, and other electronic components are electrically connected to the main substrate 12 by
`mounting, wiring, or the like.
`[0048]
`
`The data processing part 9 includes an IC component such as a CPU, and has a function for sensing a pulse rate
`by performing predetermined processing such as fast Fourier transform processing (FFT processing) after amplifying a
`pulse signal generated by the PD 6 using an amplifier or the like once and analyzing the processing result. Furthermore,
`the data processing part 9 records the sensed pulse rate in the memory 14 and displays it on the display part 11 based on
`input from each button 20 described below. Moreover, the data processing part 9 also has a function for comprehensively
`controlling other components.
`[0049]
`
`The display part 11 is, for example, a liquid crystal display device such as an LCD (Liquid Crystal Display),
`and has, for example, a time display function for displaying a time counted by a non-illustrated crystal oscillator, and a
`function for displaying other various information in addition to the above-described pulse rate. For example, the time,
`date, day of the week, remaining power amount of the rechargeable battery 13, and the like may be displayed.
`[0050]
`
`Furthermore, the housing 2 is provided with, as illustrated in FIG. 1 and FIG. 2, a plurality of a button 20; for
`example, three of the buttons 20 disposed on the upper surface 2b of the housing 2 and under the display part 11, and one
`button 20 disposed on the side surface of the housing 2. By depressing these respective buttons 20, various kinds of
`operations may be performed. For example, operations such as start measurement and stop measurement of pulse rate,
`switch display between pulse rate and time, and data transmission of pulse rate data recorded in the memory 14 to
`external equipment may be performed.
`[0051]
`
`Moreover, an external connection terminal (charging means) 21 for supplying power from outside of the
`charger or the like to the rechargeable battery 13 and charging it is provided on the side surface of the housing 2.
`Note that the external connection terminal 21 may be protected by attaching a cover or the like to cover the
`external connection terminal 21. In doing so, the external connection terminal 21 may be