JP 2004-337605 A 2004.12.2
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`(19) [Issuing Country] Japan Patent Office (JP)
`(12) [Publication Name] Gazette of Unexamined Patent Applications (A)
`(11) [Publication Number] 2004-337605 (P2004-337605A)
`(43) [Publication Date] December 2, 2004 (2004.12.2)
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`
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`[FI]
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`(51) [Int.Cl.7] A61B 5/145
`G01J 1/02
`G01N 21/35
`A61B 5/14 310
`G01J 1/02 P
`G01N 21/35 Z
`[Theme Codes (Reference)] 2G059, 2G065, 4C038
`[Examination Request] Not Yet Received
`[Number of Claims] 35
`[Application Format] Online (OL)
`[Total Number of Pages] 23
`
`(21) [Application Number] 2004-128918 (P2004-128918)
`(22) [Filing Date] April 23, 2004 (2004.4.23)
`(31) [Priority Number] 2003-118301 (P2003-118301)
`(32) [Priority Date] April 23, 2003 (2003.4.23)
`(33) [Priority Country] Japan (JP)
`(71) [Applicant]
`[Identification Number] 000103493
`[Name] OTAX Co., Ltd.
`[Address] 1215 Nippa-cho, Kohoku-ku, Yokohama-shi, Kanagawa-ken
`(71) [Applicant]
`[Identification Number] 503068875
`[Name] Yukio YAMADA
`[Address] 3-30-14-406 Takaidohigashi, Suginami-ku, Tokyo
`(71) [Applicant]
`[Identification Number] 803000045
`[Name] Campus Create Co., Ltd.
`[Address] 1-48-14 Okusawa, Setagaya-ku, Tokyo
`(74) [Agent]
`[Identification Number] 100091904
`[Attorney]
`[Name] Shigeo NARUSE
`(72) [Inventor]
`[Name] Yukio YAMADA
`[Address] 3-30-14-406 Takaidohigashi, Suginami-ku, Tokyo
`
` Continued on Last Page
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`APPLE 1004
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`JP 2004-337605 A 2004.12.2
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`(54) [Title of the Invention]
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`Optical Probe, Measurement System Using the Same, and Reflected Light Detecting Method
`Using the Same
`
`(57) [Abstract]
`
`[Problem]
`
`To provide an optical sensor that is easy to reduce in size. To provide an optical sensor that
`is less susceptible to heat generated by the light emitting unit.
`
`[Solution]
`
` A
`
` light emitting unit 11 emits light toward a reflecting unit 131 which has a diffuse reflective
`surface. The emitted light passes through an optical passage 14 before reaching the
`reflecting unit 131. The reflecting unit 131 then diffusely reflects the light from the light
`emitting unit 11 back toward the optical passage 14. The interior of the optical passage 14
`is an integrating sphere due to the diffuse reflection of light by the reflecting unit 131. The
`optical passage 14 sends the light diffusely reflected by the reflecting unit 131 from the end
`portion 141 toward a fingernail 511. Some of the transmitted light is scattered and reflected
`inside a finger 51 and is received by a light receiving unit 12.
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`[Selected Drawing] Fig. 13
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`JP 2004-337605 A 2004.12.2
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`[Claims]
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`[Claim 1]
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`An optical probe comprising a light emitting unit, a light receiving unit, a reflecting unit, and
`an optical passage, the light receiving unit receiving light that has been emitted by the light
`emitting unit and that has passed through the optical passage and the outside, the
`reflecting unit reflecting light that has passed from the light emitting unit into the optical
`passage back into the optical passage, and the optical passage sends light emitted from the
`light emitting unit to the light receiving unit via the reflecting unit or the outside.
`
`[Claim 2]
`
`An optical probe according to claim 1, wherein the light emitting unit emits light toward the
`reflecting unit or the optical passage.
`
`[Claim 3]
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`An optical probe according to claim 1, wherein the light emitting unit emits light toward the
`outside.
`
`[Claim 4]
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`An optical probe according to any one of claims 1 to 3, wherein the light emitting unit emits
`light having at least two wavelengths.
`
`[Claim 5]
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`An optical probe according to any one of claims 1 to 4, wherein the light emitting unit
`includes an LED or light emitting laser diode.
`
`[Claim 6]
`
`An optical probe according to any one of claims 1 to 4, wherein the light emitting unit
`includes a first light emitting unit and a second light emitting unit, the first light emitting
`unit includes an LED or a laser diode that emits light at a first wavelength, and the second
`light emitting unit includes an LED or a laser diode that emits light at a second wavelength.
`
`[Claim 7]
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`An optical probe according to any one of claims 1 to 6, wherein the light receiving unit
`includes a photodiode that detects received light.
`
`[Claim 8]
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`An optical probe according to any one of claims 1 to 7, wherein the reflecting unit has a
`diffuse reflective surface.
`
`[Claim 9]
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`An optical probe according to any one of claims 1 to 8, wherein the reflecting unit is formed
`into a spherical shape.
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`JP 2004-337605 A 2004.12.2
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`[Claim 10]
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`An optical probe according to any one of claims 1 to 9, further comprising a main body,
`wherein the reflecting unit is formed on an inner surface of the main body, and the main
`body is deformable.
`
`[Claim 11]
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`An optical probe according to any one of claims 1 to 10, wherein the optical passage
`comprises an end portion arranged around the light emitting unit or the light receiving unit.
`
`[Claim 12]
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`An optical probe according to any one of claims 1 to 11, wherein the interior of the optical
`passage is filled with a transparent material.
`
`[Claim 13]
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`An optical probe according to claim 12, wherein some or all of the transparent material is an
`epoxy resin.
`
`[Claim 14]
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`An optical probe according to claim 12, wherein some or all of the transparent material is a
`silicone resin.
`
`[Claim 15]
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`An optical probe according to any one of claims 1 to 14, wherein the light receiving unit or
`the light emitting unit is arranged on a board, and the board is deformable.
`
`[Claim 16]
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`An optical probe according to any one of claims 1 to 15, wherein the light emitting unit is
`arranged on a board, and the board has heat transferring properties that guide heat
`generated by the light emitting unit toward the outside.
`
`[Claim 17]
`
`An optical probe according to any one of claims 1 to 4, wherein the light emitting unit
`includes a light guide.
`
`[Claim 18]
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`An optical probe according to any one of claims 1 to 17, wherein the light receiving unit
`includes a light guide.
`
`[Claim 19]
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`An optical probe comprising a light emitting unit, a light receiving unit, a reflecting unit, and
`an optical passage, the light emitting unit emits light toward the reflecting unit, the
`reflecting unit faces the light emitting unit and returns light that has been emitted from the
`light emitting unit to the optical passage, the optical passage is arranged between the light
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`JP 2004-337605 A 2004.12.2
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`emitting unit and the reflecting unit and the optical passage sends light emitted from the
`light emitting unit and reflected by the reflecting unit to the outside, and the light receiving
`unit receives light that has been emitted by the light emitting unit and that has passed
`through the optical passage and the outside.
`
`[Claim 20]
`
`An optical probe comprising a light emitting unit, a light receiving unit, a reflecting unit, and
`an optical passage, the light emitting unit emits light toward the outside, the optical
`passage takes in light that has been emitted by the light emitting unit and that has passed
`through the outside, and guides the light to the reflecting unit, the reflecting unit reflects
`the light that has been taken into the optical passage and sends the light to the light
`receiving unit via the optical passage, and the light receiving unit receives the light that has
`been sent by the optical passage.
`
`[Claim 21]
`
`An optical probe according to claim 19 or 20, wherein the light emitting unit is arranged on
`one surface of the board, and the light receiving unit is arranged on the other surface of the
`board.
`
`[Claim 22]
`
` A
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` measurement system comprising: an optical probe according to any one of claims 1 to
`21; and an analysis unit that analyzes the characteristics of the light received by the optical
`probe.
`
`[Claim 23]
`
` A
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` reflected light detecting method comprising:
`(1) a step of emitting light that has been emitted from the light emitting unit from the
`periphery of the light receiving unit to the outside; and
`(2) a step of receiving some of the light that has been emitted to the outside and that has
`passed through the outside with the light receiving unit.
`
`[Claim 24]
`
` A
`
` detecting method according to claim 23, wherein the light emitted from the light emitting
`unit is diffusely reflected and then emitted in step (1).
`
`[Claim 25]
`
` A
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` reflected light detecting method comprising:
`(1) a step of emitting light from the light emitting unit to the outside;
`(2) a step of taking some of the light that has been emitted toward the outside and that has
`passed through the outside into the optical passage from the periphery of the light emitting
`unit; and
`(3) a step of receiving the light that has been taken into the optical passage with the light
`receiving unit.
`
`[Claim 26]
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`JP 2004-337605 A 2004.12.2
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`A detecting method according to claim 25, wherein the light that has been taken into the
`optical passage is diffusely reflected and then received by the light receiving unit in step
`(3).
`
`[Claim 27]
`
`An optical probe according to claim 21, wherein the board includes a first board unit, a
`second board unit, and an intermediate layer, the first board unit is arranged on one surface
`of the board, the second board unit is arranged on the other surface of the board, the
`intermediate layer is arranged between the first board unit and the second board unit, and
`the intermediate layer has conductive properties.
`
`[Claim 28]
`
`An optical probe according to claim 21, wherein the board includes a first board unit, a
`second board unit, and an intermediate layer, the first board unit is arranged on one surface
`of the board, the second board unit is arranged on the other surface of the board, the
`intermediate layer is arranged between the first board unit and the second board unit, and
`the intermediate layer has light blocking properties.
`
`[Claim 29]
`
`An optical probe according to any one of claims 1 to 9, further comprising a main body, the
`reflecting unit is formed on an inner surface of the main body, and a conductive material is
`provided on the outside surface of the main body.
`
`[Claim 30]
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`An optical probe according to claim 21, further comprising a protective portion that covers
`at least a portion of the periphery of the light receiving unit arranged on the board, wherein
`the protective portion comprises a conductive material.
`
`[Claim 31]
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`An optical probe according to any one of claims 1 to 21, wherein a fingernail attachment is
`attached around the end portion of the optical passage, and the outer surface of the
`fingernail attachment is formed in a substantially cylindrical shape.
`
`[Claim 32]
`
`An optical probe according to claim 31, wherein the fingernail attachment has light blocking
`properties to the outside of the position facing the end portion of the optical passage.
`
`[Claim 33]
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`An optical probe according to claim 21, further comprising a protective portion that covers
`at least a portion of the periphery of the light receiving unit arranged on the board, wherein
`the protective portion has light blocking properties.
`
`[Claim 34]
`
`An optical probe according to any one of claims 12 to 14, wherein a light scattering medium
`is arranged inside the transparent material.
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`JP 2004-337605 A 2004.12.2
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`[Claim 35]
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`An optical probe according to claim 21, further comprising a heat conductor, the light
`emitting unit is arranged at a position facing the reflecting unit, and the heat conductor
`extends from the vicinity of the light emitting unit to the reflecting unit or to the outside
`thereof.
`
`[Detailed Description of the Invention]
`
`[Technical Field]
`
`[0001]
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`The present invention relates to an optical probe, a measurement system using the optical
`probe, and a reflected light detecting method using the optical probe. More specifically, the
`present invention relates to a reflection-type optical probe.
`
`[Background Art]
`
`[0002]
`
`The reflection-type optical sensor described in Patent Document 1 is a typical example. This
`optical sensor detects light (reflected light) that has been directed toward the surface of the
`human body, scattered inside the human body, and returned toward the exposed surface.
`The oxygen saturation of blood can be measured by detecting this reflected light. A device
`that measures oxygen saturation of blood is known as a pulse oximeter.
`
`[0003]
`
`A reflection-type optical sensor can be used simply by attaching it to the surface of the
`human body (for example, to a finger). In the case of a transmission-type optical sensor, a
`body part of the subject is interposed between a light emitting unit and a light receiving
`unit, which may cause injury or discomfort such as pressure. Therefore, a reflection-type
`optical sensor places less of a burden on the subject than a transmission-type optical
`sensor.
`
`[0004]
`
`If the size of reflection-type optical sensors could be reduced, the restrictions on body parts
`that can be used would be reduced. For example, if the size were sufficiently reduced, they
`could be used on the fingernail of the little finger or on the fingernail of a child.
`
`[0005]
`
`The optical sensor described in Patent Document 1 has an additional problem in that the
`LED used to emit light also generates heat, and the patient is exposed to this heat because
`the optical sensor is attached to the surface of a fingernail. As a result, the exposure time
`and power consumption (that is, the amount of light generated) have to be limited in order
`to suppress the amount of heat that is generated.
`
`[Patent Document 1]
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`JP 2004-337605 A 2004.12.2
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`JP 2001-501847 A
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`[Disclosure of the Invention]
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`[Problem to Be Solved by the Invention]
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`[0006]
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`The present invention was devised in light of these circumstances. One object of the present
`invention is to provide an optical probe and measurement system using this optical probe
`that are easy to reduce in size. Another object of the present invention is to provide an
`optical sensor that does not expose the test subject (whether a person, animal, or thing) to
`heat generated by the light emitting unit.
`
`[Means for Solving the Problem]
`
`[0007]
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`An optical probe of the present invention comprises a light emitting unit, a light receiving
`unit, a reflecting unit, and an optical passage. The light receiving unit receives light that has
`been emitted by the light emitting unit and that has passed through the optical passage and
`the outside. The reflecting unit reflects light that has passed from the light emitting unit into
`the optical passage back into the optical passage. The optical passage sends light emitted
`from the light emitting unit to the light receiving unit via the reflecting unit or the outside.
`
`[0008]
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`The light emitting unit may emit light toward the reflecting unit or the optical passage.
`
`[0009]
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`The light emitting unit may emit light toward the outside.
`
`[0010]
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`The light emitting unit may emit light having at least two wavelengths.
`
`[0011]
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`The light emitting unit may include an LED or light emitting laser diode.
`
`[0012]
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`The light emitting unit may include a first light emitting unit and a second light emitting
`unit. The first light emitting unit may include an LED or a laser diode that emits light at a
`first wavelength. The second light emitting unit may include an LED or a laser diode that
`emits light at a second wavelength.
`
`[0013]
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`The light receiving unit may include a photodiode that detects received light.
`
`[0014]
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`JP 2004-337605 A 2004.12.2
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`The reflecting unit may have a diffuse reflective surface.
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`[0015]
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`The reflecting unit may be formed into a spherical shape.
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`[0016]
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`The optical probe may further comprise a main body. The reflecting unit can be formed on
`an inner surface of the main body, and the main body can be deformable.
`
`[0017]
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`The optical passage may comprise an end portion arranged around the light emitting unit or
`the light receiving unit.
`
`[0018]
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`The interior of the optical passage may be filled with a transparent material. Some or all of
`the transparent material may be an epoxy resin. Some or all of the transparent material
`may be a silicone resin.
`
`[0019]
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`The light receiving unit or the light emitting unit may be arranged on a board. The board
`may be deformable.
`
`[0020]
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`The light emitting unit may be arranged on a board, and the board may have heat
`transferring properties that guide heat generated by the light emitting unit toward the
`outside.
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`[0021]
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`The light emitting unit may include a light guide such as an optical fiber.
`
`[0022]
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`The light receiving unit may include a light guide such as an optical fiber.
`
`[0023]
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`An optical probe of the present invention may have the following configuration. Specifically,
`the optical probe comprises a light emitting unit, a light receiving unit, a reflecting unit, and
`an optical passage. The light emitting unit emits light toward the reflecting unit. The
`reflecting unit faces the light emitting unit and returns light that has been emitted from the
`light emitting unit to the optical passage. The optical passage is arranged between the light
`emitting unit and the reflecting unit and the optical passage sends light emitted from the
`light emitting unit and reflected by the reflecting unit to the outside. The light receiving unit
`receives light that has been emitted by the light emitting unit and that has passed through
`the optical passage and the outside.
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`JP 2004-337605 A 2004.12.2
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`[0024]
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`An optical probe of the present invention may have the following configuration. Specifically,
`the optical probe comprises a light emitting unit, a light receiving unit, a reflecting unit, and
`an optical passage. The light emitting unit emits light toward the outside. The optical
`passage takes in light that has been emitted by the light emitting unit and that has passed
`through the outside, and guides the light to the reflecting unit. The reflecting unit reflects
`the light that has been taken into the optical passage and sends the light to the light
`receiving unit via the optical passage. The light receiving unit receives the light that has
`been sent by the optical passage.
`
`[0025]
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`The light emitting unit may be arranged on one surface of the board, and the light receiving
`unit may be arranged on the other surface of the board.
`
`[0026]
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` A
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` measurement system of the present invention comprises an optical probe described
`above, and an analysis unit that analyzes the characteristics of the light received by the
`optical probe.
`
`[0027]
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` A
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` reflected light detecting method of the present invention comprises:
`(1) a step of emitting light that has been emitted from the light emitting unit from the
`periphery of the light receiving unit to the outside; and
`(2) a step of receiving some of the light that has been emitted to the outside and that has
`passed through the outside with the light receiving unit.
`
`[0028]
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`The light emitted from the light emitting unit can be diffusely reflected and then emitted in
`step (1).
`
`[0029]
`
` A
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` reflected light detecting method of the present invention may have the following
`configuration. Specifically, the reflected light detecting method comprises:
`(1) a step of emitting light from the light emitting unit to the outside;
`(2) a step of taking some of the light that has been emitted toward the outside and that has
`passed through the outside into the optical passage from the periphery of the light emitting
`unit; and
`(3) a step of receiving the light that has been taken into the optical passage with the light
`receiving unit.
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`[0030]
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`The light that has been taken into the optical passage can be diffusely reflected and then
`received by the light receiving unit in step (3).
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`[0031]
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`JP 2004-337605 A 2004.12.2
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`In an optical probe of the present invention, the board may include a first board unit, a
`second board unit, and an intermediate layer. The first board unit is arranged on one
`surface of the board. The second board unit is arranged on the other surface of the board.
`The intermediate layer is arranged between the first board unit and the second board unit.
`The intermediate layer has conductive properties.
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`[0032]
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`The intermediate layer may have light blocking properties.
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`[0033]
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`An optical probe of the present invention may further comprise a main body, the reflecting
`unit may be formed on an inner surface of the main body, and a conductive material may be
`provided on the outside surface of the main body.
`
`[0034]
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`An optical probe of the present invention may further comprise a protective portion that
`covers at least a portion of the periphery of the light receiving unit arranged on the board,
`and the protective portion may comprise a conductive material.
`
`[0035]
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`In an optical probe of the present invention, a fingernail attachment may be attached
`around the end portion of the optical passage, and the outer surface of the fingernail
`attachment may be formed in a substantially cylindrical shape.
`
`[0036]
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`The fingernail attachment may have light blocking properties to the outside of the position
`facing the end portion of the optical passage.
`
`[0037]
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`An optical probe of the present invention may further comprise a protective portion that
`covers at least a portion of the periphery of the light receiving unit arranged on the board,
`and the protective portion may have light blocking properties.
`
`[0038]
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`In an optical probe of the present invention, a light scattering medium may be arranged
`inside the transparent material.
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`[0039]
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`An optical probe of the present invention may further comprise a heat conductor. The light
`emitting unit may be arranged at a position facing the reflecting unit. The heat conductor
`may extend from the vicinity of the light emitting unit to the reflecting unit or to the outside
`thereof.
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`[Effect of the Invention]
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`JP 2004-337605 A 2004.12.2
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`[0040]
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`The present invention is able to provide an optical probe that is easy to reduce in size. The
`present invention is also able to provide an optical sensor that creates some distance
`between the light emitting unit and the subject (or target object), and thus does not expose
`the test subject or test object to heat generated by the light emitting unit.
`
`[Best Mode for Carrying Out the Invention]
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`[0041]
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`(Configuration of 1st Embodiment)
`
` A
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` measurement system according to the first embodiment of the present invention will now
`be described with reference to Fig. 1 to Fig. 13. The measurement system in the present
`embodiment is used as a pulse oximeter. The measurement system is composed primarily
`of an optical probe 1, an analysis unit 2, wiring 3, and a securing unit 4 (see Fig. 1). In the
`present embodiment, the measurement system is attached to the hand 5 of the
`measurement subject.
`
`[0042]
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`The optical probe 1 primarily includes a light emitting unit 11, a light receiving unit 12, a
`main body 13, an optical passage 14, a board 15, and a protective portion 16 (see Fig. 2 to
`Fig. 11).
`
`[0043]
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`The light emitting unit 11 includes a first light emitting unit 111 and a second light emitting
`unit 112 (see Fig. 5, Fig. 10 and Fig. 11). The first light emitting unit 111 is an LED serving
`as the light emitting object that emits light at a first wavelength. The light at the first
`wavelength can be, for example, red light at a wavelength around 660 [nm]. The second
`light emitting unit 112 is an LED serving as a light emitting object that emits light at a
`second wavelength. The light at the second wavelength can be, for example, infrared light
`at a wavelength around 880 [nm]. However, the light emitting unit 11 may be configured to
`use only a single light emitting object. The light emitting object does not have to be an LED.
`Another light emitting object such as a laser diode or a lamp may also be used. One or more
`light emitting objects such as LEDs may be used. The first and second light emitting units
`111, 112 are attached to one surface of the board 15 (the surface facing the main body 13).
`As a result, the light emitting unit 11 emits light toward the reflecting unit 131 (described
`later) or the optical passage 14.
`
`[0044]
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`In the present embodiment, the light receiving unit 12 uses a photodiode as the light
`receiving object. The light receiving unit 12 is attached to the other surface (the surface
`facing the outside) of the board 15 (see Fig. 5, Fig. 9 and Fig. 10). As a result, the light
`receiving unit 12 receives light that has been emitted from the light emitting unit 11 and
`that has passed through the optical passage 14 and the outside (for example, the inside of
`the target subject).
`
`[0045]
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`JP 2004-337605 A 2004.12.2
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` A
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` spherical reflecting unit 131 is formed on one surface (the inner surface) of the main body
`13 (see Fig. 2, Fig. 3 and Fig. 5). The main body 13 is made entirely of a hard resin.
`However, the main body 13 may be made of a flexible resin or a material other than a resin.
`
`[0046]
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`The reflecting unit 131 is made of a material with high reflectance (such as a white
`material) that reflects light (particularly infrared light or red light). The reflecting unit 131 is
`also formed with fine unevenness (that is, a rough surface; not shown). As a result, the
`reflecting unit 131 is a diffuse reflective surface. The fine unevenness (rough surface) can
`be obtained by applying, for example, a fine white powder. The reflecting unit 131 reflects
`light that has entered the optical passage 14 from the light emitting unit 11 back into the
`optical passage 14.
`
`[0047]
`
`The optical passage 14 is a space formed between the reflecting unit 131 (that is, the inner
`surface of the main body 13) and the light emitting unit 11 (see Fig. 5). The optical passage
`14 (that is, the portion through which the light passes) 141 includes an end portion that is
`arranged around the light emitting unit 11. The interior of the optical passage 14 is filled
`with a transparent material 142. The transparent material 142 is preferably a material such
`as an epoxy resin that can dissipate heat generated by the light emitting unit. However,
`another material such as silicone resin can also be used as a transparent material 142. For
`example, the portion in contact with the human body can be made of a flexible silicone
`resin, and the rest can be made of an epoxy resin. The optical passage 14 sends the light
`that has been emitted by the light emitting unit 11 to the light receiving unit 12 via the
`reflecting unit 131 and the outside (for example, the inside of the subject). The end portion
`141 of the optical passage 14 is formed around the light receiving unit 12. Here, "periphery"
`does not necessarily mean the entire circumference, and can also mean a portion of the
`circumference. The end portion 141 of the optical passage 14 faces the outside around the
`light receiving unit 12 except for the portion corresponding to the board 15.
`
`[0048]
`
`The board 15 is attached to one side of the main body 13. One end of the board 15 extends
`substantially to the center of the optical passage 14 formed on the inner surface side of the
`reflecting unit 131. The other end of the board 15 extends to the outside of the main body
`13. The light emitting unit 11 and the light receiving unit 12 are attached near one end of
`the board 15. As a result, the light emitting unit 11 attached to the board 15 is arranged at
`a position substantially facing the center of the reflecting unit 131. The light receiving unit
`12 faces the outside of the main body 13 as described above while attached to the board
`15. The board 15 is a flexible board and is imparted with flexibility. In other words, the
`board 15 is deformable. The surface of the board 15 in contact with the optical passage 14
`is a preferably diffuse reflective surface except for the light emitting unit 11 and the light
`receiving unit 12.
`
`[0049]
`
`The protective portion 16 is attached to the surface of the board 15 as shown in Fig. 2, Fig.
`3, and Fig. 5. The protective portion 16 includes a hole 161 that passes through in the
`thickness direction (see Fig. 5). The light receiving unit 12 is housed inside the hole 161.
`The interior of the hole 161 is filled with a transparent material 162 similar to the
`
`
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`13
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`(14)
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`JP 2004-337605 A 2004.12.2
`
`transparent material 142 filling the optical passage 14. Transparent material 162 may be a
`different material from transparent material 142.
`
`[0050]
`
`The analysis unit 2 includes a signal amplifier 21, an A/D converter 22, a CPU 23, an
`interface unit 24, a memory unit 25, a display unit 26, a control panel 27, and a power
`supply 28 (see Fig. 12).
`
`[0051]
`
`The signal amplifier 21 is a unit that amplifies signals from the light receiving unit 12 in the
`optical probe 1. The A/D converter 22 is a unit that converts analog signals from the optical
`probe 1 into digital signals and sends them to the CPU 23. The CPU 23 is a unit that
`processes signals sent from the A/D converter 22 in accordance with a program stored in
`the memory unit 25.
`
`[0052]
`
`The interface unit 24 is a unit that transfers signals and electric power between the CPU 23
`on one end and the memory unit 25 to the power supply 28 on the other.
`
`[0053]
`
`The memory unit 25 stores the programs and data needed for signal processing. The display
`unit 26 displays the results of processing performed by the CPU 23, and can be, for
`example, a liquid crystal display. The display unit 26 is arranged so that it can be seen from
`the outside (see Fig. 1).
`
`[0054]
`
`The control panel 27 is a unit used to give external instructions (such as "start") to the
`analysis unit 2.
`
`[0055]
`
`The power supply 28 can be, for example, a battery. The power supply 28 supplies the
`power required to operate the analysis unit 2. The power supply 28 supplies electric power
`to the light emitting unit 11 via the interface unit 24 and wiring 3. The amount of power
`supplied (that is, the amount of light emitted) and the length of time power is supplied (that
`is, the amount of time light is emitted) from the power supply 28 to the light emitting unit
`11 is controlled by the CPU 23. The analysis unit 2 can consist of a suitable component such
`as a microcomputer chip.
`
`[0056]
`
`The wiring 3 connects the board 15 in the optical probe 1 and the signal amplifier 21 in the
`analysis unit 2 to transmit signals and supply power between the two. The wiring 3 and the
`board 15 are removable.
`
`[0057]
`
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`14
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`

`

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`(15)
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`JP 2004-337605 A 2004.12.2
`
`The securing unit 4 is band shaped, and both ends are attached to the analysis unit 2. The
`securing unit 4 can be, for example, a stretchable band. The securing unit 4 can be any
`object that can secure the analysis unit 2 to the body.
`
`[0058]
`
`(Operation of 1st Embodiment)
`
`An example of a reflected light detecting method using the device in the embodiment
`described above will now be explained. Before the measurement is conducted, a clear
`adhesive (not shown) is applied to the surface of the fingernail 511 on the thumb 51 of the
`subject's hand 5 (see Fig. 1). The optical probe 1 is then attached to the fingernail 511. At
`this time, the side of the optical probe 1 with the light receiving unit 12 is facing the surface
`of the fingernail 511 (see Fig. 13). An adhesive layer may be provided on the bottom
`surface of the main body 13 (the surface in contact with the fingernail 511) may be used as
`the method of bonding the optical probe 1. The analysis unit 2 is then attached to the wrist
`52 using the securing unit 4.
`
`[0059]
`
`Next, power is supplied from the power supply 28 in the analysis unit 2 to the first light
`emitting unit 111 in the light emitting unit 11 via the CPU 23. As a result, the first light
`emitting unit 111 emits light. The red light emitted from