JP2008126017A - Optical sensor, and measurement system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical sensor which allows a measurement object to be less prone to be affected by heat generation. <P>SOLUTION: A main body 13 includes a recessed inner surface where at least a part of the surface is made to be a reflective surface. A light emitting section 11 is arranged on the inner surface of the main body 13. A light passage 14 is the passage for transmitting the light emitted from the light emitting section 11 to an external part. A light receiving part 12 receives the light which is emitted from the light emitting section 11 and passes through the external part. The light emitting section 11 is arranged apart from the measurement object at the inner surface side of the main body 13, thereby suppressing the affection by heat generation on the measurement object. Besides, the reflecting section 17 may be arranged at a position opposing to the light emitting section 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical sensor and a measurement system using the same. In particular, the present invention relates to a reflective optical sensor.

  As a conventional reflective optical sensor, for example, there is one described in Patent Document 1 below. This optical sensor detects light (reflected light) that has been irradiated on the surface of the human body, scattered inside the human body, and then returned to the irradiated surface. By detecting this reflected light, the oxygen saturation of blood can be measured. A device that measures oxygen saturation in blood is called a pulse oximeter.

  Such a reflective optical sensor can be used simply by being attached to the surface of a human body (for example, a finger). On the other hand, since the transmissive optical sensor sandwiches a part of the subject's body between the light emitter and the light receiver, discomfort such as pain and pressure may occur. Therefore, the reflection type optical sensor has an advantage that the burden on the subject is less than that of the transmission type.

  By the way, if the reflective optical sensor can be made smaller than the conventional one, the restriction on the use site is reduced. If it is sufficiently small, it can be used, for example, on the nail of a little finger or a child's nail.

  Moreover, since the light sensor described in Patent Document 1 has the LED for light emission adhered to the surface of the nail, there is a problem that the subject is easily affected by heat generation. Therefore, in the conventional one, measures such as limiting the light emission time and power consumption (that is, the light emission amount) to suppress the heat generation amount are required.

Therefore, the present inventors have proposed an optical sensor (optical probe) described in Patent Document 2 below. According to this, it becomes possible to reduce the size of the optical sensor while suppressing the influence of heat generation from the light emitting unit (for example, LED).
JP-T-2001-501847 JP 2004-337605 A

  By the way, in the conventional optical sensor, if the influence of heat generation from the light emitting portion can be further reduced, it is expected that further miniaturization and increase in the light emission amount will be possible.

  The present invention has been made in view of such circumstances. A main object of the present invention is to provide an optical sensor capable of reducing the influence of heat generation from a light emitting unit.

  The optical sensor according to the present invention includes a main body, a light emitting unit, an optical path, and a light receiving unit. The main body includes a concave inner surface at least part of which is a reflecting surface. The light emitting unit is disposed on the inner surface of the main body. And the said light emission part is arrange | positioned in the position which will be spaced apart from the surface of a measuring object. The light path sends out the light emitted from the light emitting part to the outside. The light receiving unit receives light emitted from the light emitting unit and passed through the outside.

  The optical sensor of the present invention may further include a reflecting portion. The surface of the reflection part is disposed at a position facing the light emitting part. Furthermore, the surface of the reflection part is a reflection surface that reflects the light emitted from the light emitting part and returns it to the light path.

  The light emitting unit may emit at least two types of wavelengths.

  A plurality of the light emitting units can be provided. Furthermore, these light emission parts can be arrange | positioned in the multiple places in the inner surface of the said main body.

  The plurality of light emitting units can be arranged at positions symmetrical to each other with respect to the center line of the optical sensor.

  The reflection surface on the inner surface of the main body can be a diffuse reflection surface.

  The surface of the reflection part can be a diffuse reflection surface.

  The measurement system according to the present invention is configured to include the optical sensor according to the present invention and an analysis unit that analyzes characteristics of light received by the optical sensor.

  ADVANTAGE OF THE INVENTION According to this invention, the optical sensor which can reduce the influence of the heat_generation | fever from a light emission part can be provided.

(Configuration of the first embodiment)
A measurement system according to the first embodiment of the present invention will be described below with reference to FIGS. The measurement system of this embodiment is used as a pulse oximeter. This measurement system is mainly composed of an optical sensor 1, an analysis unit 2, a wiring 3, and a fixture 4 (see FIG. 1). Moreover, this measurement system is attached to the measurement subject's hand 5 in this embodiment.

  The optical sensor 1 includes a light emitting unit 11, a light receiving unit 12, a main body 13, an optical path 14, a substrate 15, a protection unit 16, and a reflection unit 17 as main components (FIGS. 2 to 7). reference).

  The light emitting unit 11 includes a first light emitting unit 111 and a second light emitting unit 112 (see FIGS. 3 and 7). Specifically, the first light emitting unit 111 is an LED as a light emitter that emits light of a first wavelength. The light having the first wavelength is, for example, red light having a wavelength near 660 [nm]. Specifically, the second light emitting unit 112 is an LED as a light emitter that emits light of the second wavelength. The light of the second wavelength is, for example, near infrared light having a wavelength near 880 [nm]. Further, the light emitter is not limited to the LED, and other light emitters such as a laser diode and a lamp may be used. The number of light emitters such as LEDs may be singular or plural. The 1st and 2nd light emission parts 111 and 112 are attached on the inner surface (surface which faces a subject's skin or nail | claw) of the main body 13 (after-mentioned). Thereby, the light emitting unit 11 emits light toward the optical path 14.

  In this embodiment, the light receiving unit 12 uses a photodiode as a light receiver. The light receiving unit 12 is attached to one surface (surface facing the outside) of the substrate 15 (see FIGS. 2 and 3). Accordingly, the light receiving unit 12 receives light emitted from the light emitting unit 11 and passed through the light path 14 and the outside (for example, inside the object).

  In the present embodiment, the main body 13 includes an inner cover 131, an outer cover 132, and a substrate 133 for a light emitting unit.

  The inner cover 131 is generally hemispherical as a whole. Thereby, the main body 13 is provided with a concave inner surface. The inner surface of the inner cover 131 is a diffuse reflection surface over almost the entire surface. Thereby, in this embodiment, at least a part of the inner surface of the main body 13 is a reflecting surface. As a method for forming the diffuse reflection surface, a conventionally known method can be used, and a detailed description thereof will be omitted. In principle, a part or all of the inner surface of the inner cover 131 may be a normal reflecting surface instead of a diffuse reflecting surface. Here, the reflection may be a property that reflects light of a wavelength to be used, and may absorb light of other wavelengths.

  At a position near the upper end of the inner cover 131 (the right end in FIG. 2), an opening 1311 that penetrates the inner cover 131 in the inner and outer directions is formed. The opening 1311 is used for attaching the substrate 133 for the light emitting unit.

  As a material of the inner cover 131, a material having poor thermal conductivity is preferable, and for example, a resin or the like is preferable.

  The outer cover 132 has a shape that covers the outer side of the inner cover 131 (see FIGS. 2 and 3). That is, the inner cover 131 is configured to be fitted inside the outer cover 132.

  An opening 1321 for wiring the substrate 15 and the substrate 133 is formed on the side portion of the outer cover 132. The material of the outer cover 132 is preferably a material having poor thermal conductivity, like the inner cover 131, and for example, resin is suitable. However, if the thermal conductivity of the material of the outer cover 132 is too poor, it may be considered that problems such as heat accumulation inside occur. In general, since it is considered that heat is radiated from the outer cover 132 to the surroundings, it is possible to use a material having good thermal conductivity as the material depending on the application and design. Further, the outer cover 132 and the inner cover 131 may be made of different materials or the same material.

  The light emitting unit substrate 133 is fitted and attached to the inside of the upper end of the opening 1311 of the inner cover 131 (see FIGS. 2 and 3). Here, one surface 1331 of the substrate 133 is arranged so as to face the inner direction of the inner cover 131.

  The light emitting unit 11 is attached to one surface 1331 of the substrate 133 (see FIGS. 2, 3 and 7). The light emitting unit 11 is supplied with power necessary for light emission via the substrate 133. In this embodiment, the light emitting part 11 is attached on the inner surface of the main body 13 by this configuration. In the present embodiment, the light emitting unit 11 is attached to the substrate 133 so that the light emitting unit 11 is sufficiently separated from the surface of the measurement target (for example, a living body) of the optical sensor 1. However, it is possible to attach the light emitting unit 11 to the inner surface of the inner cover 131. Also in this case, it is preferable to arrange the light emitting unit 11 at a position separated from the surface of the measurement target.

  The one surface 1331 of the substrate 133 is preferably a diffuse reflection surface from the viewpoint of diffusing light and making the intensity uniform, but can also be a simple reflection surface.

  The substrate 133 is preferably made of a material having high thermal conductivity. Thereby, heat can be radiated from the light emitting unit 11 through the substrate 133. Further, since the substrate 133 does not directly touch the living body surface, the thermal influence on the living body can be kept low.

  The light path 14 is a space formed on the inner surface side of the main body 13 (see FIGS. 2 and 3). The optical path 14 includes an end portion (that is, a portion where light enters and exits) 141 disposed around the substrate 15.

  The light path 14 is filled with a transparent material 142. The transparent material 142 is preferably a material that does not easily transmit or dissipate heat generated by the light emitter, that is, a material having poor thermal conductivity, such as an epoxy resin or a silicone resin. However, other materials can be used as the transparent material 142. Further, for example, only a portion that contacts the human body may be a flexible silicone resin, and the other portion may be an epoxy resin.

  The light path 14 sends the light emitted from the light emitting unit 11 to the outside by reflection on the inner surface of the inner cover 131, and further passes (that is, via) reflection or refraction at the outside (for example, inside the object). The light is sent to the light receiving unit 12. Of course, part of the light emitted from the light emitting unit 11 may be directly sent to the outside without being reflected by the inner surface of the inner cover 131.

  The end portion 141 of the light path 14 is formed around the light receiving portion 12. Here, the periphery does not necessarily mean the entire circumference, but includes a case where it is a part of the entire circumference. The end portion 141 of the light path 14 faces the outside around the light receiving portion 12 except for the portion corresponding to the substrate 15 (see FIG. 4).

  A substrate 15 for attaching the light receiving unit 12 is attached to one surface side (opening side) of the main body 13. One end of the substrate 15 is extended to a substantially central position in the main body 13 (see FIG. 2). The other end of the substrate 15 extends to the vicinity of the outside of the main body 13. The light receiving unit 12 is attached to one surface side (side facing the object) of the substrate 15 in the vicinity of one end of the substrate 15. That is, the light receiving unit 12 is directed toward the outside of the main body 13 in a state of being attached to the substrate 15.

  As the substrate 15, for example, a hard substrate such as a glass epoxy substrate is used. However, the substrate 15 may be provided with flexibility by using a flexible substrate. Further, it is desirable that the surface of the substrate 15 facing the optical path 14 is a reflection surface, particularly a diffuse reflection surface.

  As shown in FIGS. 2 and 3, the protection unit 16 is attached to one surface side (side facing the object) of the substrate 15. A hole 161 penetrating in the thickness direction is formed in the protection part 16 (see FIGS. 2, 3 and 4). The light receiving unit 12 is disposed at a position corresponding to the hole 161. That is, it is configured such that light from the outside reaches the light receiving unit 12 through the hole 161. A space between the hole 161 and the light receiving unit 12 can be filled with a transparent material similar to the transparent material 142 filled in the light path 14.

  The reflector 17 is disposed on the other surface side (main body side) of the substrate 15. In this example, the reflecting portion 17 is disposed at a position opposite to the light receiving portion 12. Further, the reflecting portion 17 is disposed so as to be substantially concentric with the inner cover 131 of the main body 13. As a result, the width of the light path 14 (that is, the gap between the inner cover 131 and the reflecting portion 17 shown in FIGS. 2 and 3) is substantially uniform except for the portion of the substrate 15.

  The surface of the reflecting portion 17 is raised on a substantially spherical surface. The surface of the reflection surface 17 is preferably a reflection surface, more preferably a diffuse reflection surface.

  The analysis unit 2 includes a signal amplifier 21, an A / D converter 22, a control unit 23, an interface unit 24, a memory unit 25, a display unit 26, an operation unit 27, and a power supply unit 28. (See FIG. 8).

  The signal amplifier 21 is a part that amplifies the signal from the light receiving unit 12 of the optical sensor 1. The A / D converter 22 is a part that converts an analog signal from the optical sensor 1 into a digital signal and sends it to the control unit 23. The control unit 23 is a part that processes the signal sent from the A / D converter 22 in accordance with a program stored in the memory unit 25.

  The interface unit 24 is a part that exchanges signals and power between the control unit 23 and the memory unit 25 to the power supply unit 28.

  The memory unit 25 stores programs and data necessary for signal processing. The memory unit 25 can store not only data necessary for measurement processing but also data as measurement results.

  The display part 26 displays the processing result in the control part 23, for example, is a liquid crystal display. The display part 26 is arrange | positioned in the position visible from the exterior (refer FIG. 1).

  The operation unit 27 is a part for inputting an external instruction (for example, operation start) to the analysis unit 2.

  The power supply 28 is a battery, for example. The power supply 28 supplies power necessary for the operation of the analysis unit 2. Further, the power supply 28 supplies power to the light emitting unit 11 via the interface unit 24 and the wiring 3. The amount of power supplied from the power supply 28 to the light emitting unit 11 (that is, the amount of light emission) or the supply timing (that is, the light emission timing) is controlled by the control unit 23. Such an analysis unit 2 can be easily configured by using appropriate components such as a microcomputer chip.

  The wiring 3 connects the substrate 15 and the substrate 133 of the optical sensor 1 to the signal amplifier 21 of the analysis unit 2 and performs signal transmission and power supply between them. The wiring 3 and the board | substrate 15 and the board | substrate 133 are detachable. In FIG. 8, the wiring 3 is simplified by describing the signal acquisition wiring and the power supply wiring as one line. However, in practice, the wiring 3 is usually a separate wiring.

  The fixture 4 is formed in a belt shape, and both ends thereof are attached to the analysis unit 2. The fixture 4 is, for example, an expandable / contractible belt. In short, the fixture 4 may be anything that can fix the analysis unit 2 to the body.

(Operation of the first embodiment)
Next, an example of a reflected light detection method using the apparatus of the present embodiment configured as described above will be described. Before the measurement, a transparent adhesive (not shown) is applied to the surface of the nail 511 (see FIG. 1) of the thumb 51 in the hand 5 of the subject. Next, the optical sensor 1 is attached to the nail 511. At this time, the light receiving unit 12 side of the optical sensor 1 is directed to the surface of the claw 511. Of course, as a method for adhering the optical sensor 1, for example, an adhesive layer may be provided on the bottom surface of the main body 13 (the surface in contact with the claw 511). Further, the analysis unit 2 is attached to the wrist 52 using the fixture 4.

  It is also possible to attach the optical sensor 1 to the abdomen of the finger (the part on the opposite side of the nail). Furthermore, it is also possible to attach the optical sensor 1 to a subject using a double-sided tape.

  Next, power is supplied from the power supply unit 28 of the analysis unit 2 to the first light emitting unit 111 of the light emitting unit 11 via the control unit 23. Thereby, the 1st light emission part 111 is light-emitted. The red light emitted from the first light emitting unit 111 passes through the light path 14 and is diffusely reflected by the inner surface of the inner cover 131 (see FIG. 9). Since the inner surface of the inner cover 131 is a diffuse reflection surface, the interior of the light path 14 is substantially an integrating sphere. Therefore, in this embodiment, the light emitted from the light emitting unit 11 is emitted from the end portion 141 of the light path 14 (that is, the exit of the light path 14) to the outside with a substantially uniform intensity regardless of the location. Moreover, in this embodiment, since the inner surface of the inner cover 131 is a diffuse reflection surface, the directivity of the light emitted from the end portion 141 can be reduced.

  In this embodiment, since the end portion 141 of the light path 14 is disposed around the light receiving unit 12, light is emitted from the periphery of the light receiving unit 12 to the outside. However, the portion corresponding to the substrate 15 is blocked by the substrate 15 and therefore does not emit light. Thus, in this specification, “periphery” does not necessarily mean the entire circumference.

  The light emitted to the outside from the end portion 141 of the light path 14 is applied to the nail 511 as an object located outside. The irradiated light is reflected after passing through a human body tissue, that is, a nail 511, a tissue under the nail, or the like. A part of the light is reflected by the surface of the claw 511 and returns to the light path 14.

  Part of the light that has passed through the human tissue passes through the hole 161 of the protection unit 16 and is received by the light receiving unit 12. The received light is photoelectrically converted by the light receiving unit 12, and the light intensity signal is sent to the analysis unit 2 as an electrical signal.

  Next, power is supplied from the power supply unit 28 to the second light emitting unit 112 of the light emitting unit 11. Thereby, the 2nd light emission part 112 is light-emitted. Infrared light emitted from the second light emitting unit 112 is received by the light receiving unit 12 as in the case of the first light emitting unit 111, and a light intensity signal is sent to the analyzing unit 2.

  Such light emission of the first light emitting unit 111 and light emission of the second light emitting unit 112 are repeated in a short cycle. It is preferable that the light emission period is sufficiently shorter than the period of the pulse wave. For example, the light emission period is set to a value of 1/10 or less of the expected pulse wave period. In this way, even when one light receiving unit 12 is used, pulse wave intensity signals can be acquired at two wavelengths.

  The control unit 23 of the analysis unit 2 obtains a variation width (a variation amount width excluding a DC component) in the intensity signal of each wavelength. Next, assuming that the fluctuation range in red light is R and the fluctuation range in near-infrared light is IR, the ratio R / IR of the fluctuation ranges is obtained. When this ratio is high, blood oxygen saturation is low, and when this ratio is low, oxygen saturation is high. Since such a data processing method is well known, further explanation is omitted. Further, the control unit 23 searches the memory unit 25 for a numerical value of the oxygen saturation corresponding to the fluctuation range ratio, outputs it to the display unit 26, and displays it.

  In this embodiment, since the light from the light emitting unit 11 is emitted from the periphery of the light receiving unit 12 to the outside, the light that has passed through a wide area can be received by the light receiving unit 12. Therefore, it is possible to acquire information on objects in a wide range. For example, since blood vessels are localized in a living tissue, fluctuations in pulse waves cannot always be captured with a narrow range of information. On the other hand, in this embodiment, there is an advantage that it is easy to catch the fluctuation of the pulse wave.

  In this embodiment, by adjusting the area of the end portion (portion facing the outside) 141 in the light path 14, the light irradiation amount to the object can be easily adjusted. The area can be adjusted, for example, by attaching a shield.

  Furthermore, in this embodiment, since the light emission part 11 is arrange | positioned at the main body 13 side (side spaced apart from the target object), there exists an advantage that a target object (for example, human body) is hard to receive to the influence of heat_generation | fever. For this reason, for example, it becomes easy to increase the light emission amount and the light emission time, and the SN ratio of the detection signal can be improved. Furthermore, there is an advantage that the subject is less likely to be injured by fever and feels uncomfortable. Further, even when the optical sensor 1 is downsized and the area of the end portion 141 of the light path 14 is thereby reduced, it is easy to obtain a sufficient amount of received light by increasing the amount of light from the light emitting unit 11. .

  Moreover, in the optical sensor of this embodiment, since the light from the light emission part 11 is discharge | released outside via the optical path 14, the light emission part 11 and the light-receiving part 12 are along the direction spaced apart from a target object. Can be arranged. In the conventional optical sensor described in Patent Document 1, the light emitting unit and the light receiving unit are arranged in a direction along the body surface. Moreover, in this conventional optical sensor, sufficient information cannot be obtained unless the light emitting part and the light receiving part are separated to some extent. Therefore, further miniaturization is difficult with the conventional optical sensor. On the other hand, since the light sensor of this embodiment can arrange the light emission part 11 and the light-receiving part 12 along the direction spaced apart from a target object, the area required for installation of a light sensor is made small ( In other words, there is an advantage that it is easy to downsize. In addition, in the present embodiment, even when the size is reduced, as described above, the object can be irradiated with light from a wide range around the light receiving unit 12, so that it is easy to ensure a sufficient amount of received light. There is an advantage.

  Furthermore, in the optical sensor of this embodiment, part of the light reflected by the surface of the claw 511 passes through the end portion 141 and reenters the optical path 14. The light that has entered the optical path 14 is emitted from the end 141 again to the outside because the inside of the optical path 14 is an integrating sphere (that is, the reflecting part 131 is a diffuse reflecting surface). . Thus, in this embodiment, a part of the emitted light can be reused. Therefore, in this embodiment, the utilization efficiency of the emitted light can be improved, and this has the advantage that the optical sensor can be further miniaturized.

  Moreover, according to the optical sensor of this embodiment, since it can be reduced in size as described above, it is easy to attach to a curved surface such as the surface of a living body or fruit or vegetable.

  Furthermore, in the optical sensor of this embodiment, if the main body 13 is made of a deformable material, it can be more easily attached to a curved surface. Further, in this optical sensor, if the transparent material 142 and the substrate 15 can be deformed, the same advantages can be obtained. Further, by using a flexible material in the transparent material 142, in particular, a portion that comes into contact with the human body, it is possible to obtain an advantage of improved adhesion and improved usability.

  Moreover, in this embodiment, since the protection part 16 is attached to the board | substrate 15, there also exists an advantage that the light-receiving part 12 and the board | substrate 15 can be protected.

  Furthermore, in the optical sensor of this embodiment, since the transparent material 142 is sealed inside the optical path 14, the strength of the main body 13 can be improved. Therefore, this optical sensor also has an advantage that an internal structure such as a substrate for the light emitting unit 11 and the light receiving unit 12 can be protected. In addition, if a material having poor thermal conductivity is used as the transparent material 142, it is possible to more reliably prevent thermal injury to a living body that is a measurement target.

  In the present embodiment, since the light emitting unit 11 is mounted on the inner surface of the main body 13, the light emitting unit 11 and the living body surface can be sufficiently separated from each other. Thereby, it becomes possible to reduce the thermal influence on a living body. Further, in the present embodiment, by making the inner cover 131, the outer cover 132, and the transparent material 142 (especially, the portion that touches the surface of the living body) for the light emitting part have poor thermal conductivity, the influence of heat generation on the living body is further increased. It can be reduced. However, it is considered that the material between the light emitting unit 11 and the living body surface can be made of a material having good thermal conductivity by taking a sufficiently large distance between the light emitting unit 11 and the living body surface. In addition, about the board | substrate 133, when the heat conductivity is bad, there exists a possibility that the heat | fever from the light emission part 11 may not escape, Therefore It is generally considered that it is not preferable to dare to reduce the heat conductivity of the board | substrate 133.

  Further, in the optical sensor of the present embodiment, since the light emitting unit 11 is provided on the substrate 133 of the main body 13, heat dissipation through the main body 13 is facilitated. For example, in the present embodiment, heat can be radiated to the outside through the substrate 133 for the light emitting unit. As a result, the amount of light emitted from the light emitting unit 11 can be increased, and the S / N ratio in the received light can be improved. Alternatively, the optical sensor 1 can be further reduced in size.

(Second Embodiment)
Next, an optical sensor 1 according to a second embodiment of the present invention will be described with reference to FIG. In the first embodiment described above, the reflecting portion 17 is provided on the other surface side of the substrate 15 for the light receiving portion. In the optical sensor 1 of the present embodiment, the reflection unit 17 is omitted.

  Even in such a configuration, a part of the light from the light emitting unit 11 is reflected by the substrate 15, the inner cover 131, and the like, and is emitted to the outside through the optical path 14.

  In the present embodiment, the other surface of the substrate 15 (the surface facing the light emitting unit 11) is preferably a diffuse reflection surface. In this case, since the light from the light emitting part 11 can be diffused, there is an advantage that the intensity of the light from the light path 14 becomes more uniform.

  Other configurations and advantages of the second embodiment are the same as those of the first embodiment, and thus further description thereof is omitted.

(Third to seventh embodiments)
Next, optical sensors 1 according to third to seventh embodiments of the present invention will be described with reference to FIGS. In these embodiments, the shape of the upper surface of the reflecting portion 17 is different from that in the first embodiment. However, the surface of the reflection part 17 in the third to seventh embodiments is a diffuse reflection surface.

  In the third to seventh embodiments, the outer cover 132 and the substrate 133 of the main body 13 are omitted. Further, the opening 1311 of the inner cover 131 is also omitted.

  Furthermore, in 3rd-7th embodiment, the light emission part 11 is arrange | positioned in the inner surface of the inner cover 131, and the upper position.

  In the third to seventh embodiments, the same advantages as those of the first embodiment can be exhibited. That is, in principle, the shape of the reflecting portion 17 may be any shape.

  However, the width of the light path 14 is preferably rotationally symmetric with respect to the center line P (see FIG. 12) of the main body 13 in order to emit light uniformly. Since the shape of the reflecting portion 17 defines the width of the light path 14, the shape of the reflecting portion 17 is preferably rotationally symmetric with respect to the center line P as in the case of the light path 14.

(Eighth embodiment)
Next, an optical sensor 1 according to an eighth embodiment of the present invention will be described with reference to FIG. In this embodiment, unlike the third to seventh embodiments, a substrate 133 is attached to the inner surface of the main body 13, and the light emitting unit 11 is attached to one surface (surface facing outward) of the substrate 133.

  Other configurations and advantages of the eighth embodiment are substantially the same as those of the third to seventh embodiments, and a detailed description thereof will be omitted.

(Ninth embodiment)
Next, an optical sensor according to a ninth embodiment of the invention will be described with reference to FIG. In this embodiment, two light emitting portions 11A and 11B are used. Each light emitting unit includes the first light emitting units 11A1 and 11B1 and the second light emitting units 11A2 and 11B2, similarly to the light emitting unit 11 described above.

  The light emitting unit 11A and the light emitting unit 11B are arranged at positions that are symmetric with respect to the center line P. Thereby, it is considered that it is easy to equalize the amount of light from the light path 14 to the outside if the amount of light from each light emitting unit is the same.

  Furthermore, if the four light emitting units 11A to 11D are configured to be used (see FIG. 18) and arranged at positions symmetrical with respect to the center line P, the amount of light emitted to the outside can be made more uniform. . Further, by increasing the number of light emitting units, the amount of light can be increased and the S / N ratio of the obtained signal can be improved. Furthermore, when the number of light emitting units is increased, the wavelength of light to be used can be increased to three or more, and detection results corresponding to light of each wavelength can be obtained.

  Other configurations and advantages of the ninth embodiment are the same as those of the first embodiment, and thus detailed description thereof is omitted.

Note that the description of each of the embodiments is merely an example, and does not indicate a configuration essential to the present invention. The configuration of each part is not limited to the above as long as the gist of the present invention can be achieved.
Furthermore, the above-described functional blocks may be combined into a single functional block. Further, the function of one functional block may be realized by cooperation of a plurality of functional blocks.

It is explanatory drawing which shows the state which attached the measurement system which concerns on 1st Embodiment of this invention to the subject's hand. It is sectional drawing of the optical sensor which concerns on 1st Embodiment of this invention. It is sectional drawing in alignment with the AA direction in the optical sensor of FIG. It is an arrow view of the B direction in the optical sensor of FIG. It is an arrow view of the C direction in the optical sensor of FIG. It is an arrow view of the D direction in the optical sensor of FIG. It is a bottom view in the state which excluded the outer cover among the main-body parts in a photosensor. It is a block diagram which shows schematic structure of the analysis part used for the measurement system of FIG. FIG. 4 is an explanatory diagram for explaining the operation of the optical sensor in FIG. 2 and corresponding to FIG. 3. It is sectional drawing of the optical sensor which concerns on 2nd Embodiment of this invention, Comprising: It is a figure corresponding to FIG. It is a schematic sectional drawing which shows the principal part of the optical sensor which concerns on 3rd Embodiment of this invention. It is a schematic sectional drawing which shows the principal part of the optical sensor which concerns on 4th Embodiment of this invention. It is a schematic sectional drawing which shows the principal part of the optical sensor which concerns on 5th Embodiment of this invention. It is a schematic sectional drawing which shows the principal part of the optical sensor which concerns on 6th Embodiment of this invention. It is a schematic sectional drawing which shows the principal part of the optical sensor which concerns on 7th Embodiment of this invention. It is a schematic sectional drawing which shows the principal part of the optical sensor which concerns on 8th Embodiment of this invention. It is a schematic sectional drawing which shows the principal part of the optical sensor which concerns on 9th Embodiment of this invention. It is explanatory drawing for demonstrating the modification of the optical sensor which concerns on 9th Embodiment of this invention, Comprising: It is the figure of the state which looked at the main body from the upper surface side.

Explanation of symbols

P Center line of the main body (Center line of the optical sensor)
DESCRIPTION OF SYMBOLS 1 Optical sensor 11 * 11A-11D Light emission part 111 * 11A1-11D1 1st light emission part 112 * 11A2-11D2 2nd light emission part 12 Light receiving part 13 Main body 131 Inner cover 1311 Opening part for board | substrate attachment 132 Outer cover 1321 For wiring Opening 133 Substrate for light emitting part 1331 One surface of substrate 14 Optical path 141 End part of optical path 142 Transparent material filled in optical path 15 Substrate for light receiving part 16 Protection part 161 Hole 17 Reflection part 2 Analysis part 21 Signal amplifier 22 A / D converter 23 Control unit 24 Interface unit 25 Memory unit 26 Display unit 27 Operation unit 28 Power supply unit 3 Wiring 4 Fixing tool 5 Hand 51 Finger 511 Nail

Claims (8)

A main body, a light emitting unit, a light path, and a light receiving unit;
The main body includes a concave inner surface at least a part of which is a reflecting surface;
The light emitting part is disposed on the inner surface of the main body,
And the light emitting part is arranged at a position that will be separated from the surface of the measurement target,
The light path is for sending light emitted from the light emitting unit to the outside,
The optical sensor, wherein the light receiving unit receives light emitted from the light emitting unit and passed through the outside. In addition, with a reflective part,
The surface of the reflective portion is disposed at a position facing the light emitting portion,
2. The optical sensor according to claim 1, wherein the surface of the reflecting portion is a reflecting surface that reflects the light emitted from the light emitting portion and returns the light to the light path.   The optical sensor according to claim 1, wherein the light emitting unit emits light of at least two types of wavelengths.   4. The optical sensor according to claim 3, wherein there are a plurality of the light emitting units, and further, the light emitting units are arranged at a plurality of locations on the inner surface of the main body.   The optical sensor according to claim 4, wherein the plurality of light emitting units are arranged at positions symmetrical to each other with respect to a center line of the optical sensor.   The optical sensor according to claim 1, wherein the reflection surface on the inner surface of the main body is a diffuse reflection surface.   The optical sensor according to claim 2, wherein a surface of the reflection portion is a diffuse reflection surface.   A measurement system comprising: the optical sensor according to claim 1; and an analysis unit that analyzes characteristics of light received by the optical sensor.

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