(19) Japan Patent Office (JP)
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`(12) Publication of Unexamined
`Patent Application (A)
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`(11) Patent Application
`Publication No.
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`2005-040261
`(P2005-040261A)
`(43) Publication Date: February 17, 2005
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`Theme Codes (reference)
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`4C017
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` FI
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` A61B 5/02 310B
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`(51) Int. Cl.7
`A61B 5/0245
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`Request for Examination: Not requested Number of Claims: 5 OL Total pages: 5
`(71) Applicant 599173826
`(21) Application No.: 2003-201849 (P2003-
`201849)
`
`
`Watex Co., Ltd.
`(22) Application Date July 25, 2003
` 32 Higashi-Shinmachi, Ota City
`Gunma Prefecture
`(74) [Agent] 100091258
` Patent Attorney Yoshimura Naoki
`(72) Inventor NUMAGA KAZUHIRO
` c/o Watex Co., Ltd.
` 32 Higashi-Shinmachi, Ota City
`Gunma Prefecture
`(72) Inventor AIZAWA NOBUYUKI
` c/o Watex Co., Ltd.
` 32 Higashi-Shinmachi, Ota City
`Gunma Prefecture
`F Term (reference) 4C017 AA09 AB02
`AC28
`
`
`Apple Inc.
`APL1010
`U.S. Patent No. 8,923,941
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`I
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`(54) PULSE WAVE SENSOR
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`(57) Abstract
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`PROBLEM TO BE SOLVED: To improve the sensitivity
`of a pulse wave sensor and the accuracy of detection of
`pulse waves by eliminating unnecessary light from
`incidenting on a light receiving device.
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`SOLUTION: The pulse wave sensor 20 is constituted so
`that a light emitting surface 21s of a light emitting device
`21 and a light receiving surface 22s of a light receiving
`device 22 are made to project onto the face of a sensor
`case 23 abutting a wrist 10 and the light emitting surface
`21s and the light receiving surface 22s are pressed
`against a wrist 10. The part of the pulse wave sensor
`excluding the light emitting surface 21s and the light
`receiving surface 22s is covered with a shell supporting
`member 29, and the rear sides of the light emitting
`device 21 and the light receiving device 22 are further
`coated with an enclosure adhesive 28 with light shutting
`off property, so that unnecessary light from the outside
`of the sensor will not come into the light emitting device
`22.
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`[Selected Drawing] FIG. 1
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`II
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`What is claimed is:
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`1. A pulse wave sensor that is provided with a pair of a light emitting device and a
`light receiving device, and that detects the pulse waves of a subject under test
`by detecting in the light receiving device the light emitted from the light emitting
`device that is reflected from the arteries of the wrist of said subject under test,
`wherein the light emitting surface of the light emitting device and the light
`receiving surface of the light receiving device are exposed to the surface of the
`sensor case abutting a wrist.
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`2. The pulse wave sensor according to Claim 1 wherein the tip of the light
`emitting device and the tip of the light receiving device project towards a side
`of a wrist.
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`3. The pulse wave sensor according to Claim 1 or Claim 2 wherein the portions
`except for the light emitting surface of the light emitting devices and the light
`receiving surface of the light receiving device are covered by a light shutting off
`member.
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`4. The pulse wave sensor according to Claim 3 wherein the outer periphery on
`the wrist side of the light emitting device and the light receiving device is
`directly covered by an exterior support member having light shutting off
`property.
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`5. The pulse wave sensor according to Claim 3 or Claim 4 wherein adhesives
`having light shutting off property are used as enclosing adhesives for enclosing
`the light emitting device and the light receiving device in the sensor case.
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`Detailed Description of the Invention
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`[Field of the Invention]
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`[0001] The present invention relates to a pulse wave sensor that emits infrared
`wavelength light onto a pulse of the wrist of a subject under test and detects the pulse
`waves of said subject from the light that is reflected by the red corpuscles within the
`arteries.
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`
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`[Description of the Prior Art]
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`[0002] For measuring the pulse rate, normally optical pulse wave sensors are widely
`used that emit infrared or near infrared light onto blood vessels and from the reflected
`light or transmitted light detect the pulse waves of the subject under test.
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`Figures 2(a) and 2(b) illustrate a conventional pulse wave sensor 20A that is attached
`to a wrist 10 and that measures the pulse waves of the subject under test by
`detecting the movement of red corpuscles in the arteries of the wrist 10. This pulse
`wave sensor 20A stores the light emitting device 21 and the light receiving device 22
`in the sensor case. The rear sides of the light emitting device 21 and light receiving
`device 22 are fixed to the sensor case 23 by the translucent sealing adhesive 24. On
`the exterior (wrist 10 side) of the light emitting surface 21s of the light emitting device
`21 and the light receiving surface 22s of the light receiving device 22 is established a
`transparent acrylic board 25 (for example, see Patent Document 1). The light emitting
`devices 21 and the light receiving devices 22 have the non-illustrated light emitting
`chips or light receiving chips covered by optical exterior packaging such as resin.
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`The light emitting chips or light receiving chips are embedded in the pedestals 21a
`and 22a of the respective optical exterior packaging. The tips of the light guide parts
`21b and 22b that project from the pedestals 21a and 22a become the respective light
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`emitting surface 21s of the light emitting device 21 and the light receiving surface 22s
`of the light receiving device 22.
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`The light emitting surface 21s and the light receiving surface 22s respectively position
`the pulse wave sensor 20A directly close to the non-illustrated pulse of the wrist 10 so
`that the test subject’s pulse waves are detected using the belt 30 inside the wrist 10.
`Moreover, it is possible to calculate the frequency of the detected pulse wave by
`counting and calculating.
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`Moreover, in Patent Document 1, the light receiving device 22 is constructed by
`centering the light emitting device 21 and positioning concentrically and symmetrically,
`but because the number and arrangement of the light emitting devices 21 and the
`light receiving devices 22 differ with different pulse wave sensors, FIG. 2 shows one
`respective example for the light emitting devices 21 and for the light receiving devices
`22.
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`[0003] In addition, with the pulse wave sensor 20A, along with covering the light guide
`part 22b of the receiving light device 22 by the light shielding tube 26 that opens onto
`the wrist 10 side, on the outer periphery of the write 10 side of the light emitting
`device 21 and the light receiving device 22, there is arranged a shell combination
`device supporting member 27 with light shielding capability that supports the wrist 10
`side of the light emitting device 21 and the light receiving device 22. Light shielding is
`used so that light from outside the sensor or near infrared light from the light emitting
`device 21 is not incident on the light receiving device 22.
`
`[0004]
`[Patent Document 1]
`Unexamined Japanese Patent Application Publication No.JP2002-360530A
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`[Problem to be solved by the invention]
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`[0005] However, in a conventional pulse wave sensor 20A, because an acrylic board
`25 is placed between the light emitting device 21 and the light receiving device 22,
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`due to the effect of transmission loss or light scattering, there was the problem that
`the sensor sensitivity gets reduced.
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`In addition, although the light guide part 22b of the light receiving device 22 is
`covered by a shield tube or a shell cum device support member 27, because the resin
`that has formed the optical outer packaging has light transmittance, there was the
`problem that unnecessary light through the acrylic board 25 or the translucent
`enclosure adhesive 24 enters the light receiving device 22.
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`[0006] An object of the present invention is, not only to improve the sensitivity of pulse
`wave sensors, but also to improve the accuracy of detection of pulse waves without
`unnecessary light entering the light receiving device.
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`[Means for Solving the Problem]
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`[0007] The invention in claim 1 of the present invention provides a pulse wave sensor
`comprising a light emitting device and a light receiving device, the light emitted from
`the light emitting device and reflected from the arterial movement of the wrist of the
`test subject is detected by the light receiving device. The light emitting surface of the
`light emitting device and the light receiving surface of the light receiving device are
`exposed at a surface of the sensor case that abuts the wrist of subject under test.
`Because of this arrangement, since the light emitting device and the light receiving
`device directly touch the wrist, and since the light from the light emitting device is
`injected into the wrist without loss, and also since only the light from the wrist enters
`the light receiving device, it becomes possible to improve the sensitivity of the sensor.
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`In addition, because there are no transparent sheets such as acrylic sheets and
`because there is no ambient light caused by transparent sheets, the accuracy of
`detection of the pulse waves is improved.
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`The invention of claim 2 is the pulse wave sensor according to claim 1 wherein,
`because of projecting the tips of the light emitting device and the light receiving
`device on the wrist side, and because the light emitting surface and the light receiving
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`surface approach the blood vessels of the wrist, it becomes possible to further
`improve the sensor sensitivity.
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`[0008] In addition, the invention in claim 3 is the pulse wave sensor of claim 1 or claim
`2, wherein, the portions of the pulse wave sensor excepting the light emitting surface
`of the light emitting device and the light receiving surface of the light receiving device
`are covered by a member having light shutting off property Because of this
`arrangement, it becomes possible to improve the detection accuracy of pulse waves,
`because of having no unnecessary light entering the light receiving device. The
`invention in claim 4 is the pulse wave sensor of claim 3 wherein, the outer periphery
`of the wrist side of the light emitting device and the light receiving device are covered
`with a shell support member having direct light shielding property. With this
`construction, it becomes possible to maintain light shielding without using a light
`shielding tube.
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`The invention in claim 5 is the pulse wave sensor of claim 3 or claim 4 wherein, an
`adhesive having light shut off property is used as the sealing adhesive for sealing
`said light emitting devices and said light receiving device in the sensor case. Because
`an adhesive having light shut off property is used as the sealing adhesive, it becomes
`possible to prevent unnecessary light from entering the light receiving device through
`the sealing adhesive.
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`[Detailed Description of the Embodiments]
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`[0009] Hereafter, a description is given, based on the drawings, of embodiments of
`the present invention. Moreover, like symbols are assigned to like portions in the
`conventional example, and descriptions thereof are omitted.
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`FIG. 1(a) and 1(b) are drawings illustrating an outline configuration of the pulse wave
`sensor 20 according to an embodiment of the present invention. 21 denotes a light
`emitting device, 22, a light receiving device, 23, a sensor case, and 28, an enclosure
`adhesive for sealing the light emitting device 21 and the light receiving device 22 in
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`the sensor case 23. In this example, an adhesive having light shut off property such
`as a black colored adhesive is used as the enclosure adhesive 28. In addition, 29 is a
`shell support member that covers the outer peripheral parts of the light guide parts
`21b and 22b of the light emitting device 21 and the light receiving device 22.
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`The pulse wave sensor 20 in this example projects from the face abutting the wrist 10
`of the sensor case 23 the light emitting surface 21s which is the tip of the light
`emitting device 21 and the light receiving surface 22s that is the tip of the light
`receiving device 22. The light emitting surface 21s and the light receiving surface 22s
`are exposed to the sensor’s exterior. The periphery of the tips of the light emitting
`device 21 and the light receiving device 22 that protrudes slightly, that is, the part that
`does not include the light emitting surface 21s and the light receiving surface 22s, is
`covered by the shell support member 29. Consequently, the face that abuts the wrist
`10 of the pulse wave sensor 20 becomes the face for which the light emitting surface
`21s and the light emitting surface 22s as well as the shell support member 29 on their
`peripheries are slightly elevated. In the case where the pulse wave sensor 20 is
`installed on the wrist, the light emitting surface 21s and the light receiving surface 22s
`are joined by pressure and the surroundings are enclosed by light shutting off
`material (shell support member 29).
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`[0010] When the pulse wave sensor 20 with this kind of construction abuts the wrist
`10, because the light emitting surface 21s of the light emitting device 21 directly abuts
`the wrist 10 and is pressed onto the skin, conventional transmission loss does not
`occur. Because all of the near infrared rays that are emitted in a direction towards the
`wrist 10 from the light emitting device 21 are injected on the wrist 10, it is possible to
`effectively use the near infrared light from the light emitting device 21.
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`The near infrared rays that are emitted in the direction towards the wrist 10 from the
`light emitting device 21 are reflected by the red blood corpuscles that flow in the non-
`illustrated arteries of the wrist 10.
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`In this example, the light receiving surface 22s of the light receiving device 22 directly
`abuts the wrist 10. Because of this arrangement and because there is no
`transmission degradation through a transparent sheet, there are improvements in
`sensor sensitivity. Because there is no ambient light caused by dispersion from a
`transparent sheet that enters the light receiving device, it is possible to improve the
`detection accuracy of pulse waves. In this case, because the light emitting surface
`21s and the light receiving surface 22s are pressed onto the skin and because the
`optical path of the near infrared rays is short, sensor sensitivity is markedly improved
`compared to the case in which the light emitting surface 21s and the light receiving
`surface 22s are merely abut the wrist 10.
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`In addition, the boundary of the light emitting surface 22s1 is covered by the shell
`support member 29 constituted from a material having light shutting off property.
`Because unnecessary light from outside the sensor does not enter the light receiving
`device, it is possible to maintain sufficient light shutting off property without using a
`light shielding tube. Furthermore, because the rear surface side of the light emitting
`device 21 and the light receiving device 22 are covered by the sealing adhesive 28
`having light shutting off property, it is possible to maintain sufficient light shutting off
`property, even for the rear face side of the light receiving device 22.
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`[0011] In this way, according to this embodiment, the light emitting surface 21s of the
`light emitting device 21 and the light receiving surface 22s of the light receiving device
`22 for the pulse wave 20 project onto a face that abuts the wrist 10 of the sensor case
`23. Because the light emitting surface 21s and the light receiving surface 22s are
`pressed onto the skin of the wrist 10, it is possible to inject near infrared rays from the
`light emitting device 21 very effectively to the wrist 10. Because the reflected light
`from the wrist 10 directly shines on the light receiving surface 22s of the light
`receiving device 22, it is possible to significantly improve sensor sensitivity. In
`addition, parts that do not include the light emitting surface 21s and the light receiving
`
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`1 The numerical identifier 22s is a mistake in the original publication. The correct numerical identifier must be
`21s. [Translator's Note]
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`surface 22s are covered by the shell support member 29. Furthermore, the rear face
`sides of the light emitting device 21 and the light receiving device 22 are covered by
`the enclosure adhesive 28. Because no unnecessary light from outside the sensor
`enters the light receiving device 22, it is possible to improve detection accuracy of the
`pulse waves.
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`[0012] Moreover, using this embodiment, a description is given for the pulse wave
`sensor 20 comprised of one each of the light emitting device 21 and the light
`receiving device 22. The present invention may be appropriately used for other pulse
`wave sensors such as the pulse wave sensor 20A that has a construction in which
`the light receiving device 22 disclosed in Patent Document 1 focuses on the light
`emitting device 21 and is concentrically and symmetrically arranged.
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`In addition, the construction that exposes to the face abutting the wrist 10 of the
`sensor case 23 the light emitting surface 21 of the light emitting device 21 and the
`light receiving surface 22s of the light receiving device 22 is not limited to the disc-
`shaped sensor case 23 as shown in FIG. 2(a). It goes without saying that it is
`possible to realize sensor cases of various forms.
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`[Effect of the Invention]
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`[0013] As described previously, the light emitting surface of the light emitting device
`and the light receiving surface of the light receiving device of the pulse wave sensor
`are exposed to the face abutting the wrist of the sensor case. Because the light
`emitting device and the light receiving device are made so as to directly face the wrist,
`it is possible to lower significantly transmission loss. Along with being able to improve
`sensor sensitivity, because no unnecessary light enters the light receiving device, it is
`possible to improve also the pulse wave’s detection accuracy.
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`In addition, along with projecting to the wrist side the tip of the light emitting device
`and the tip of the light receiving device, because there is covering by a material
`having light shutting off property, locations other than the light emitting surface and
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`the light receiving surface, it is possible to reduce unnecessary light entering the light
`receiving device and it is possible to improve the pulse wave’s detection accuracy.
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`[Brief Explanation of the Drawings]
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`[FIG. 1] A drawing illustrating the construction of the pulse wave sensor relating to an
`embodiment of the present invention.
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`[FIG. 2] A drawing illustrating the construction of a conventional pulse wave sensor.
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`[Description of the Reference Symbols]
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`10- wrist, 20- pulse wave sensor, 21- light emitting device, 22-light receiving device,
`23- sensor case, 28- enclosure adhesive, 29- shell support member.
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`[FIG. 1]
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`Certification of Translation Accuracy
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` state under penalty of perjury under the laws of the United States of America that the translation
`of the Japanese patent publication “JP2005040261A” into English is true and correct.
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`Executed on November 17, 2016.
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` ______________________________
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`Name: Robert M. Ginns
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`Title: Translator
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`G&D Translation Services, Volkertstr. 19/28 Vienna, 1020 Austria Tel: +43 676 928 80 50 – e-mail: translations@gd-translation.com
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