JP2011156011A - Wrist mounted biological information detector and wrist mounted biological information measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wrist mounted biological information detector or the like capable of improving detection accuracy. <P>SOLUTION: The wrist mounted biological information detector includes: a light emitting unit 14 for emitting light of an emission wavelength band (λ01-λ02) including a wavelength of interest (λ0); a light receiving unit 16 for receiving light R1' having biological information; and first and second filters 15 and 19-1 provided between a part to be detected and the light receiving unit. The first filter suppresses light of a first wavelength band (λ11-λ12) within a reception wavelength band higher than the wavelength of interest. In the first wavelength (λ11) at a lower limit, the characteristic increase of external light intensity R3' propagated inside a body to be inspected between the peripheral side and the center side of a part to be detected is equal to or less than the wavelength (λ1) of a change point from a first gradient C1 to a second gradient C2. The second filter suppresses the light of a second wavelength band (λ21-λ22) within the reception wavelength band higher than the wavelength of interest, and satisfies formulas λ<λ21≤λ12 and λ12<the maximum wavelength (λmax) of a receiver sensitivity band≤λ22. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wrist-worn biological information detector, a biological information measuring device, and the like.

  The biological information measuring device measures biological information such as a human pulse rate, blood oxygen saturation, body temperature, heart rate, and the like, and an example of the biological information measuring device is a pulse meter that measures the pulse rate. In addition, a biological information measuring device such as a pulse meter may be incorporated in an electronic device such as a clock, a mobile phone, a pager, or a personal computer, or may be combined with an electronic device. The biological information measuring device includes a biological information detector that detects biological information. The biological information detector includes a light emitting unit that emits light toward a detection site of a subject to be inspected (user), and a detection site. And a light receiving unit that receives light having biological information.

  A biological information detector or biological information measuring device that can be worn on a human wrist can be referred to as a wrist-mounted biological information detector or biological information measuring device, and can be called a wrist-worn biological information detector or biological information measuring device. The device can be incorporated into, for example, a wristwatch (in a broad sense, a wrist-worn electronic device).

  Patent Document 1 discloses a pulse meter (biological information measuring device in a broad sense). Patent Document 1 discloses a filter that allows transmission of only a wavelength of 650 [nm] or less in order to remove the influence of external light that passes through a finger (for example, external light L2 in FIG. 13 of Patent Document 1) (Patent Document 1). The filter showing the transmission characteristics indicated by the broken line in FIG.

  Patent Document 2 also discloses a pulse meter (biological information measuring device in a broad sense). In Patent Document 2, in order to remove the influence of external light transmitted through the finger, the wavelength of the light emitting part of the pulse meter is set to 300 [nm] to 700 [nm] (for example, 350 [shown in FIG. 4 of Patent Document 2] nm] to [600 nm] and the wavelength of the light receiving portion of the pulse meter is 700 [nm] or less (for example, 300 [nm] to 600 [nm] shown in FIG. 5 of Patent Document 2). Main sensitivity characteristics).

JP 61-048338 A Japanese Patent Laid-Open No. 08-080288

  When measuring the pulse rate of, for example, a wrist other than a finger with a pulse meter such as Patent Document 1 and Patent Document 2, the detection accuracy of the biological information detector is not good due to the influence of noise caused by external light.

  According to some aspects of the present invention, it is possible to provide a wrist-worn biological information detector and a biological information measuring device that can improve detection accuracy or measurement accuracy.

One aspect of the present invention is a light emitting unit that emits light in a light emission wavelength band including a wavelength of interest toward a detection site of a test object;
A light-receiving unit that has sensitivity to a light-receiving wavelength band including the light-emitting wavelength band, and that receives light having biological information, in which light emitted from the light-emitting unit is reflected at the detection site;
A first filter provided between the detected part and the light receiving unit;
A second filter provided between the detected part and the light receiving unit,
The first filter transmits light of the wavelength of interest, suppresses light of a first wavelength band in the light receiving wavelength band higher than the wavelength of interest, and the first wavelength band is a first wavelength band A band from a wavelength to a second wavelength higher than the first wavelength, and the first wavelength is between the distal side of the detection site and the central side of the detection site within the subject. The increase characteristic of the intensity of external light propagating through the first wavelength is equal to or less than the wavelength of the transition point at which the first gradient shifts to the second gradient that is steeper than the first gradient.
The second filter transmits light of the wavelength of interest, suppresses light of a second wavelength band within the light receiving wavelength band, and the second wavelength band is at least from the second wavelength, The present invention relates to a wrist-worn biological information detector that is higher than the second wavelength and has a band up to a third wavelength equal to or greater than the light receiving wavelength band.

  According to one embodiment of the present invention, light in a light emission wavelength band (for example, λ01 to λ02 and λ01 <λ0 <λ02) including a wavelength of interest (for example, λ0) emitted from the light emitting unit is reflected at the detection site. By this, it becomes light containing biological information, and this is detected by the light receiving unit, thereby measuring the biological information. The external light is composed of light having various wavelengths including the emission wavelength band, and may become noise when a part of the external light (propagation light) propagated through the inspected body is received by the light receiving unit. It has been found that the external light that can be noise is light that propagates in the inspection object between the distal side of the detection site and the central side of the detection site. In addition, an increase in the intensity of external light that can be a noise has a wavelength (for example, λ1) at a transition point at which the first inclination (slow inclination) shifts to the second inclination (steep inclination) steeper than the first inclination. It was found that light below the wavelength of the change point is weak and can be ignored as noise. The wrist-worn biological information detector includes a first filter and a second filter. Both the first and second filters transmit light of the wavelength of interest (λ0), but the wavelength bands of the light to be suppressed are the first wavelength band (for example, λ11 to λ12) and the second wavelength band ( For example, λ21 to λ22) is different (however, some overlap is allowed). In the first wavelength band which is the characteristic of the first filter, the lower limit first wavelength (λ11) is not more than the wavelength (λ1) at the changing point (λ0 <λ11 ≦ λ1). On the other hand, the second wavelength band, which is the characteristic of the second filter, has a lower limit wavelength (λ21) of at least the second wavelength (λ12), that is, the second wavelength (λ12) or less (λ21 ≦ λ12), The upper limit third wavelength (λ22) is higher than the second wavelength (λ12) and is not less than the light receiving wavelength band (λ12 <λmax ≦ λ22, where λmax is the maximum wavelength of the reception wavelength band). In this way, the light of the first and second wavelength bands (λ11 to λ22) is suppressed by the first and second filters, so that the wavelength λ1 that is necessarily included in these wavelength bands (λ11 to λ22). The above external light (propagation light: noise) is suppressed. On the other hand, the reflected light in part or all of the emission wavelength band including at least the wavelength of interest (λ0) is transmitted through the first and second filters. Therefore, the detection accuracy (S / N ratio) of the biological information detector is improved. Since there was no one type of filter that can suppress all the wavelength bands (λ11 to λ22) of light to be suppressed, in one aspect of the present invention, noise is reduced by the two-stage light suppression effect of the first and second filters. Reduced. The suppression of light by the first and second filters means that the intensity of transmitted light with respect to the incident light to the filter is preferably 10% or less, more preferably 5% or less. Good.

  In the aspect of the invention, the first filter may be a dye absorption filter.

  The dye absorption filter can be made of, for example, a resin such as gelatin resin or polyester resin, and a first filter that suppresses the shortest wavelength of external light (propagation light) propagated through the body to be inspected can be easily prepared. it can.

  In the aspect of the invention, the second filter may be a dielectric multilayer filter.

  The transmittance of the dielectric multilayer filter with respect to the wavelength of interest can be easily set higher than, for example, the transmittance of the dye absorption filter with respect to the wavelength of interest, and the light emitted from the light emitting unit can be easily transmitted.

In one embodiment of the present invention, the wrist-worn biological information detector comprises:
A substrate that is made of a material that is transparent to the wavelength of interest, the light emitting unit is disposed on a first surface, and the light receiving unit is disposed on a second surface opposite to the first surface;
A reflective portion that is disposed on the second surface side with respect to the substrate, has a reflective surface, and reflects light having the biological information by the reflective surface;
And a contact portion that is disposed on the first surface side with respect to the substrate, is made of a material that is transparent to the wavelength of interest, and has a contact surface with the object to be inspected.

  In plan view, the light emitting unit and the light receiving unit can overlap with each other through the substrate, and the wrist-worn biological information detector can be downsized.

  In the aspect of the invention, the first filter may be disposed on at least one of the substrate, the light receiving unit, and the reflecting unit.

  When the transmittance of the first filter with respect to the wavelength of interest is not 100 [%], the first filter transmits the wavelength of interest of the light emitted from the light emitting unit, but may also suppress the wavelength of interest of the light emitted from the light emitting unit. is there. By not providing the first filter in the optical path between the light emitting unit and the detection site, it is possible to prevent a decrease in the efficiency of the light emitting unit.

  In the aspect of the invention, the second filter may be provided on at least one of the substrate, the light receiving unit, the reflecting unit, and the contact unit excluding the contact surface.

  When the second filter is provided on the contact surface due to the influence of oil or the like of the object to be inspected, the performance of the second filter may be deteriorated. Therefore, the deterioration of the performance of the second filter can be prevented by not providing the second filter on the contact surface.

  In one embodiment of the present invention, the wavelength of the change point may be in the range of 565 nm to 595 nm.

  As a result of considering the activity status of the object to be inspected (for example, the user), the wavelength (λ1) of the above-mentioned change point, that is, the shortest wavelength (λ1) that can be noise among the external light propagated through the object to be inspected is, for example, 565 nm to It can be set in the range of 595 nm.

Another aspect of the present invention provides the biological information detector described above,
A biological information measuring unit that measures the biological information from a light reception signal generated in the light receiving unit,
The biological information is related to a biological information measuring apparatus characterized by a pulse rate.

  According to the other aspect of this invention, the measurement accuracy of a biological information measuring device can be improved using the biological information detector with improved detection accuracy.

The structural example of the biological information detector of this embodiment. FIGS. 2A and 2B are explanatory diagrams of an approach path of external light. An example of the intensity characteristic of external light. An example of the transmission characteristic of a 1st filter. 5A and 5B are examples of the transmission characteristics of the second filter. An example of the intensity | strength characteristic of the light which a light emission part emits. An example of the sensitivity characteristic of the light which a light-receiving part receives. The other structural example of the biometric information detector of this embodiment. An example of the transmission characteristic of the light which passes along the board | substrate with which the light permeable film was coated. An appearance example of a light transmission film. An example of storing a substrate. The other structural example of the biometric information detector of this embodiment. FIG. 13A, FIG. 13B, and FIG. 13C are configuration examples of the first reflecting portion. 14A and 14B are external appearance examples of the first reflecting portion and the light emitting portion. An example of the appearance of the light receiving part. FIGS. 16A and 16B are external views of a biological information measuring device including a biological information detector. The structural example of a biological information measuring device. 18A and 18B show another configuration example of the biological information detector of the present embodiment. The connection example of a light-receiving part and a 2nd light-receiving part.

  Hereinafter, this embodiment will be described. In addition, this embodiment demonstrated below does not unduly limit the content of this invention described in the claim. In addition, all the configurations described in the present embodiment are not necessarily essential configuration requirements of the present invention.

1. Biological information detector 1.1. Configuration Example of Biological Information Detector FIG. 1 shows a configuration example of the biological information detector of this embodiment. As shown in FIG. 1, the biological information detector includes a light emitting unit 14, a light receiving unit 16, a first filter 15, and a second filter 19-1. The light emitting unit 14 emits light R1 that is directed to a detection site O (for example, a blood vessel) of a test object (for example, a user). The light receiving unit 16 receives light R1 ′ (reflected light) having biological information in which the light R1 emitted from the light emitting unit 14 is reflected by the detection site O. Both the first filter 15 and the second filter 19-1 are provided between the detection site O and the light receiving unit 16.

  The light emitting unit 14 emits light in a light emission wavelength band (λ01 to λ02) illustrated in FIG. 6, for example. On the other hand, the light receiving unit 16 has sensitivity in a wide light receiving wavelength band (also referred to as a light receiving sensitivity band) including the light emitting wavelength band shown in FIG. 6 (see FIG. 7). Thus, since the receiving sensitivity band of the light receiving unit 16 (FIG. 7) is wider than the emission wavelength band of the light emitting unit 14 (FIG. 6), the light receiving unit 16 receives light other than the emission wavelength band as noise, for example. There is a possibility that the S / N may decrease. The first filter 15 and the second filter 19-1 are provided to suppress light that can be noise from being received by the light receiving unit 16. The first filter 15 and the second filter 19-1 do not suppress the light of the wavelength of interest in which the biological information is reflected in the reflected light R1 '. The wavelength of interest is included in the emission wavelength band (λ01 to λ02) shown in FIG. 6, and is a wavelength at which the intensity of the reflected light R1 ′ changes by being absorbed at the detection site (blood vessel) O (for example, FIG. 6). λ0: λ01 <λ0 <λ02). An example of transmission characteristics of the first filter 15 and the second filter 19-1 will be described later.

  In the example of FIG. 1, the detection site O (for example, a blood vessel) is inside the test object. The first light R1 travels inside the object to be examined and diffuses or scatters in the epidermis, dermis and subcutaneous tissue. Thereafter, the first light R1 reaches the detection site O and is reflected by the detection site O. The reflected light R1 'at the detection site O is diffused or scattered by the subcutaneous tissue, dermis and epidermis. Thereafter, the reflected light R <b> 1 ′ travels toward the light receiving unit 16. The first light R1 is partially absorbed by the blood vessel. Therefore, the absorption rate in the blood vessel changes due to the influence of the pulse, and the amount of reflected light R1 'at the detection site O also changes. In this way, the biological information (for example, the pulse rate) is reflected in the reflected light R1 'at the detection site O. More specifically, hemoglobin in blood has a significantly larger extinction coefficient for light in the band from 300 nm to 700 nm than that for infrared light. When the first light R1 having an emission wavelength band within a wavelength range of 300 nm to 700 nm, for example, is irradiated toward the object to be inspected in accordance with the light absorption characteristics of hemoglobin, it is reflected at the detection site (blood vessel) O. The intensity of the reflected light R1 ′ thus changed greatly following the blood volume change. Therefore, the emission wavelength band (λ01 to λ02) including the wavelength of interest (λ0) is set in a range of at least 300 nm to 700 nm. In the present embodiment, the emission wavelength band (λ01 to λ02) including the wavelength of interest (λ0) is set as shown in FIG. 6 and does not overlap with the wavelength band of the external light R3 ′ that can be noise indicated by a broken line in FIG. It is set as follows.

  On the other hand, the external light R3 is diffused or scattered inside the object to be inspected. Thereafter, the external light R 3 ′ (propagating light) that has propagated through the body to be inspected without reaching the detection site O travels toward the light receiving unit 16. The biological information (pulse rate) is not reflected in the external light R3 '(propagating light) that has propagated through the subject in the first direction DR1. Since the external light R3 (for example, sunlight) is composed of light having various wavelengths, a part of the external light R3 ′ (propagation light) propagated through the inspected body is as shown in FIG. It is suppressed by the second filter 19-1. However, the other part of the external light R3 '(propagating light) that has propagated through the body to be inspected passes through the second filter 19-1, as shown in FIG. That is, as the light suppression cutoff characteristic of the second filter 19-1, it is not possible to suppress light of all wavelengths within the reception sensitivity band in the external light R3 'propagating through the subject. Therefore, the first filter 15 suppresses the external light R3 ′ that could not be suppressed by the second filter 19-1. Thus, since the external light R3 '(propagation light: noise) propagated through the body to be inspected is suppressed in two stages, the detection accuracy (SN ratio) of the biological information detector is improved.

  In addition, although patent document 1 is examining the influence of the external light (For example, external light L2 of FIG. 13 of patent document 1) which permeate | transmits a finger | toe, the influence of the propagation light which propagated the inside of a wrist is examined. Absent. In other words, the present inventor replaced the first filter 15 and the second filter 19-1 with a filter that allows transmission of only a wavelength of 650 nm or less (the transmission characteristic indicated by the broken line in FIG. 4 of Patent Document 1). It was recognized that the effect of propagating light propagating through the wrist cannot be ignored when the filter is applied to a wrist-worn biological information detector.

  Patent Document 2 also examines the influence of external light transmitted through the finger, but does not examine the influence of propagated light propagating through the wrist. In other words, the inventor sets the sensitivity wavelength band of the light receiving unit 16 to 700 [nm] or less (for example, main sensitivity characteristics of 300 [nm] to 600 [nm] shown in FIG. 5 of Patent Document 2). However, I realized that the influence of the propagating light that propagated inside the wrist cannot be ignored.

  In addition, as shown in FIG. 1, the biological information detector can include a reflection unit 18, a contact unit 19, and a substrate 11. The reflection unit 18 has a reflection surface, and reflects light R1 'having biological information on the reflection surface. The reflecting unit 18 can have a reflecting surface on a dome surface (spherical surface or parabolic surface) provided in the optical path between the light emitting unit 14 and the light receiving unit 16. In the example of FIG. 1, in a cross-sectional view, the reflection surface of the reflection portion 18 represents an arc that defines a spherical surface, but may represent a parabola that defines a paraboloid. The contact portion 19 has a contact surface with the object to be inspected. The light emitting unit 14 is disposed on the substrate 11 on the contact unit 19 side, and the light receiving unit 16 is disposed on the substrate 11 on the reflecting unit 18 side. Both the contact portion 19 and the substrate 11 are made of a material that is transparent to the wavelength of interest of the light emitted from the light emitting portion 14. The contact portion 19 is made of, for example, glass, and the substrate 11 is made of, for example, polyimide.

  Since the substrate 11 is sandwiched between the reflecting portion 18 and the contact portion 19, even if the light emitting portion 14 and the light receiving portion 16 are arranged on the substrate 11, it is necessary to provide a mechanism for supporting the substrate 11 itself. There is no, and the number of parts decreases. Further, since the substrate 11 is made of a material that is transparent to the wavelength of interest, the substrate 11 can be disposed in the middle of the optical path from the light emitting unit 14 to the light receiving unit 16, and the substrate 11 is positioned at a position other than the optical path, for example, the reflection unit 18. There is no need to store it internally. Thus, a biological information detector that can be easily assembled can be provided. Moreover, the reflection part 18 can increase the light quantity which reaches | attains the light-receiving part 16, and the detection accuracy (S / N ratio) of a biological information detector improves.

  The thickness of the substrate 11 is, for example, 10 [μm] to 1000 [μm]. Wiring to the light emitting unit 14 and wiring to the light receiving unit 16 can be formed on the substrate 11. Although the board | substrate 11 is a printed circuit board, for example, generally the printed circuit board is not comprised with the transparent material. In other words, the present inventors have dared to construct the printed circuit board with a material transparent to at least the wavelength of interest of the light-emitting portion 14. The thickness of the contact portion 19 is, for example, 1 [μm] to 3000 [μm].

  The configuration example of the biological information detector is not limited by FIG. 1, and the shape or the like of a part of the configuration example (for example, the reflection unit 18) may be changed. Further, the biological information may be oxygen saturation in the blood, body temperature, heart rate, and the like, and the detection site O may be on the surface SA of the test object. In the example of FIG. 1, the first light R <b> 1 is drawn as one line, but actually, the light emitting unit 14 emits a lot of light in various directions. In addition, the external light R3 is drawn as two lines. Actually, however, a lot of external light enters the inside of the inspection object from various directions. A lot of propagated external light R3 ′ is directed to the biological information detector.

1.2. Influence of External Light FIGS. 2A and 2B are explanatory diagrams of an entrance path of external light. Although a large amount of external light enters the inside of the inspection object from various directions, as shown in FIG. 2 (A), in the plan view, the external light R3 is, for example, the peripheral side (for example, the back of the hand) of the detection site O. ) From the first direction DR1 from the central side to the central side (base of the arm). The external light R3 is diffused or scattered inside the object to be examined, for example, at a place where there are no obstacles such as tendons and bones. Further, the external light can enter the inside of the inspection object from the second direction from the central side to the distal side of the detection site O, for example. As shown in FIG. 2B, the external light R3 ′ (propagating light) that has propagated through the inspected object in the first direction DR1 returns to the outside of the inspected object. The present inventor has recognized that such propagating light gives noise to the wrist-worn biological information detector. On the other hand, the external light R4 traveling from the back side of the wrist to the front side hardly transmits the inside of the object to be inspected, and the present inventor does not need to consider the influence of the external light R4 directed from the back side of the wrist to the front side. Recognized.

  The solid line in FIG. 3 shows an example of the intensity characteristic of sunlight (external light R3 in a broad sense). In the example of FIG. 3, the intensity of the external light R3 having a wavelength of 530 [nm] shows the maximum value. The dotted line in FIG. 3 indicates the sunlight in which the sunlight R3 indicated by the solid line propagates inside the surface of the wrist (external light R3 ′ propagated in the subject to be examined in a broad sense), and this sunlight R3 ′ is the light receiving unit 16. Can be a noise. In addition, since the intensity | strength of sunlight R3 'which propagated the inside of the surface of a wrist is very small compared with sunlight R3 itself, in the example of FIG. 3, it is expanded 30 times.

  As shown in FIG. 3, sunlight R3 'propagated inside the wrist surface has a maximum value at a wavelength of 710 [nm]. Sunlight R3 'propagating through the wrist surface has a wavelength of less than 700 [nm], which is the lower limit of the living body window (range of 700 [nm] to 1100 [nm]). Further, the intensity of sunlight (propagation light) R3 ′ having a wavelength of 650 [nm] shows 90 [%] of the maximum value (710 [nm]), and sunlight (propagation) having a wavelength of 650 [nm]. The intensity of light (R3 ′) shows a maximum value of 50 [%], and the intensity of sunlight (propagating light) R3 ′ having a wavelength of 600 [nm] shows a maximum value of 20 [%]. This is because the influence of sunlight (propagating light) R3 ′ cannot be ignored in a filter that allows transmission of only a wavelength of 650 [nm] or less taught in Patent Document 1, and 700 [ nm] means that the influence of sunlight (propagating light) cannot be ignored even in a light receiving unit having a sensitivity wavelength band of less than [nm].

  In addition, the intensity of sunlight (propagating light) R3 ′ having a wavelength of 590 [nm] indicates [10%] of the maximum value (710 [nm]), and sunlight having a wavelength of 580 [nm] ( The intensity of the propagating light (R3 ′) indicates 5% of the maximum value. In particular, the wavelength 580 [nm] of sunlight (propagating light) R3 ′ indicated by a dotted line in the example of FIG. 3 has a gentle inclination (first inclination) of an increase characteristic of external light intensity propagating inside the wrist surface. This is the wavelength (λ1) at the transition point from C1 to the steep slope (second slope) C2. The amount of sunlight (propagating light) R3 'having a wavelength of less than 580 [nm] is as small as less than 5% compared to the intensity of the entire sunlight (propagating light) R3'. Accordingly, the external light R3 ′ having a wavelength of 580 [nm] or more which is the wavelength (λ1) of the change point can become noise for the light receiving unit 16, and the wavelength of 580 [nm] which is the wavelength (λ1) of the change point. This light can be referred to as the shortest wavelength that can cause noise in the external light R3 ′ that has propagated through the body to be inspected. As a result of studying the intensity characteristics of sunlight (propagation light) shown in FIG. 3 by the present inventor, 580 [nm] slightly higher than the emission wavelength band (the maximum range in FIG. 6 is 485 [nm] to 575 [nm]). It is important to effectively suppress sunlight (propagation light) R3 ′ having the above wavelength. However, the wavelength (λ1) of the change point only needs to be higher than the wavelength of interest (λ0), and may be included in the emission wavelength band.

  Note that the ease with which hemoglobin in the blood is associated with oxygen changes depending on the activity state of the subject (user), and the shortest wavelength (580 [nm]) that can be noise in the external light R3 ′ propagated through the subject. ) May vary from 565 [nm] to 595 [nm]. Therefore, the wavelength of interest, the emission wavelength band, or the light suppression characteristics at the first and second filters 15 and 19-1 can be set as appropriate according to the wavelength band of light to be suppressed or removed.

1.3. Transmission characteristics and light suppression characteristics of the first and second filters The first filter 15 transmits light of the wavelength of interest (λ0: λ01 <λ0 <λ02) within the emission wavelength band (λ01 to λ02) shown in FIG. Thus, light in the first wavelength band (λ11 to λ12: λ0 <λ11 <λ12 shown in FIG. 4) within the light receiving wavelength band higher than the wavelength of interest (λ0) is suppressed. The first wavelength band is a band from the first wavelength (λ11) to the second wavelength (λ12), and the first wavelength (λ11) is the peripheral side of the detection site O and the detection site O. The increase characteristic of the external light intensity R3 ′ propagating through the body to be inspected with the central side is equal to or less than the wavelength (λ1) of the changing point at which transition from the gentle slope C1 to the steep slope C2 shown in FIG. 3 (λ0 <λ11). ≦ λ1).
The second filter 19-1 transmits the wavelength of interest (λ0) and suppresses light in the second wavelength band (λ21 to λ22 in FIGS. 5A and 5B) within the light receiving wavelength band. The lower limit (λ21) of the second wavelength band is equal to or greater than the second wavelength (λ21), and the upper limit (λ22) is higher than the second wavelength (λ21) and equal to or greater than the light receiving wavelength band (maximum wavelength λmax in FIG. 7). The third wavelength (λ22).
In this way, the first and second filters 15 and 19-1 transmit all the wavelength of interest λ0 within the emission wavelength band, and all of the propagation wavelengths R3 ′ that are noises within the reception sensitivity band are equal to or greater than the shortest wavelength (λ1). Light can be suppressed.
1.3.1. Specific Example of First Filter Characteristic FIG. 4 shows an example of the transmission characteristic of the first filter 15. In the example of FIG. 4, the first filter 15 is a dye absorption filter. In the example of FIG. 4, the transmittance of light having a wavelength in the range of 600 [nm] to 700 [nm] indicates 0 [%]. The transmittance of light having a wavelength in the range of 580 [nm] to 730 [nm] is 5 [%] or less. The transmittance of light having a wavelength in the range of 565 [nm] to 740 [nm] is 10 [%] or less. The first wavelength band in which the first filter 15 exhibits light suppression characteristics is preferably a transmittance of 10% or less, but in the present embodiment, for example, the wavelength band has a transmittance of 5% or less. A range from 580 [nm] to 730 [nm] is referred to as a first wavelength band. If the transmittance is preferably 10% or less, and more preferably 5% or less, the external light R3 ′ propagating inside the living body is originally weak, so the light receiving unit 16 is limited to the transmittance of 10% or less. This is because the S / N can be kept relatively high even if the light is received at. Thus, the first filter 15 can suppress light in the first wavelength band (for example, the first wavelength λ11 = 580 [nm] to the second wavelength λ12 = 730 [nm]). The first wavelength band starts from the shortest wavelength (580 [nm]) that can become noise in at least the external light R3 ′ (propagating light), and thus has not been studied in Patent Document 1 and Patent Document 2. The influence of (propagating light) can be suppressed.

  With respect to sunlight (propagating light) R3 'indicated by a dotted line in the example of FIG. 3, the intensity of light having a wavelength of 700 [nm] or more is higher than the intensity of light having a wavelength near 600 [nm]. Therefore, in the example of FIG. 4, the influence of the transmittance of light R3 ′ having a wavelength of 700 [nm] or more is larger than the influence of the transmittance of light having a wavelength near 600 [nm]. As the transmission characteristics of the first filter 15 (dye absorption filter) in FIG. 4, the transmittance of light R3 ′ having a wavelength of 700 [nm] or more is increased, so that light R3 ′ having a wavelength of 700 [nm] or more is particularly suppressed. For this purpose, a second filter 19-1 is provided.

  The dye absorbing filter 15 can be made of a resin such as a gelatin resin or a polyester resin mixed with an absorbing dye, and may be a resin sheet. In addition, the pigment | dye absorption filter comprised with a resin sheet may be used for the stage lighting apparatus which emits a specific color, for example. The dye absorbing filter may be made of a plastic (synthetic resin) mixed with an absorbing dye, and may be used, for example, for a sunglasses lens.

1.3.2. Specific Example of Second Filter Characteristic FIGS. 5A and 5B show an example of the transmission characteristic of the second filter 19-1. In the example of FIGS. 5A and 5B, the second filter 19-1 is a dielectric multilayer filter. In FIG. 5A, light is transmitted perpendicularly to the second filter 19-1, and the incident angle is 0 [degree]. In FIG. 5B, light is transmitted obliquely through the second filter 19-1, and the incident angle is 45 [degrees]. As shown in FIGS. 5A and 5B, the transmittance of the dielectric multilayer filter depends on the incident angle of light.

  In the example of FIG. 5A, the transmittance of light having a wavelength in the range of 670 [nm] to 1300 [nm] is 1 [%] or less. The transmittance of light having a wavelength in the range of 650 [nm] to 1300 [nm] is 5 [%] or less. The transmittance of light having a wavelength in the range of 645 [nm] to 1300 [nm] is 10 [%] or less. In the present embodiment, similarly to the first filter 15, when the incident angle is 0 °, the transmittance ranges from 650 [nm] to 1300 [nm], which is a wavelength band of, for example, 5% or less. It is called a wavelength band. Also in this case, if the transmittance is, for example, 5% or less, the external light intensity R3 ′ propagating inside the living body is originally weak, so even if it is received by the light receiving unit 16, the S / N is compared. This is because it can be maintained high. In this manner, the second filter 19-1 can suppress light in the second wavelength band (for example, λ21 = 650 [nm] to third wavelength λ22 = 1300 [nm]). The second wavelength band is at least from the upper limit of the first wavelength band (for example, the second wavelength λ12 = 740 [nm]) to the third wavelength λ22 that is not less than the maximum wavelength λmax of the reception sensitivity band shown in FIG. By suppressing this light, the influence of sunlight (propagation light) R3 ′ that cannot be suppressed by the first filter 15 can be suppressed. Moreover, the first and second filters 15 and 19-1 partially overlap the first and second wavelength bands that suppress light, so that one filter characteristic has an attenuation gradient (particularly the first filter 15). Light having a wavelength of 700 [nm] to 800 [nm], the light is suppressed by the other filter whose light suppression characteristics overlap in the band of the attenuation gradient. Can do.

  In the example of FIG. 4 showing the characteristics of the first filter 15, the transmittance at a wavelength near 700 [nm] exceeds 1 [%]. Therefore, as a transmission characteristic of the second filter 19-1 (dielectric multilayer filter), as shown in FIG. 5A, the transmittance at a wavelength near 700 [nm] is, for example, 1 [%] or less. It is preferable to set.

  In the example of FIG. 5B, which has a characteristic with an incident angle of 45 °, the transmittance of light having a wavelength in the range of 620 [nm] to 1170 [nm] is 5 [%] or less. The transmittance of light having a wavelength in the range of 615 [nm] to 1175 [nm] is 10 [%] or less. In the present embodiment, a range of 620 [nm] to 1170 [nm], which is a wavelength band having a transmittance of 5% or less when the incident angle is 45 °, is referred to as a second wavelength band. Also in this case, if the transmittance is, for example, 5% or less, the external light intensity R3 ′ propagating inside the living body is originally weak, so even if it is received by the light receiving unit 16, the S / N is compared. This is because it can be maintained high. As described above, even when the incident angle is 45 °, the second filter 19-1 has the light in the second wavelength band (for example, λ21 = 620 [nm] to third wavelength λ22 = 1170 [nm]). Can be suppressed. Even when the incident angle is 45 °, the second wavelength band is at least the upper limit of the first wavelength band (for example, the second wavelength λ12 = 740 [nm]), and the maximum wavelength of the reception sensitivity band shown in FIG. By suppressing the light up to the third wavelength λ22 that is not less than λmax, the influence of sunlight (propagation light) R3 ′ that cannot be suppressed by the first filter 15 can be suppressed.

The dielectric multilayer filter can be configured by laminating a plurality of dielectric layers. For example, the first dielectric layer and the second dielectric layer are alternately accumulated a plurality of times, for example, by a sputtering apparatus. The refractive index of the first dielectric layer (eg, TiO ₂ film) is higher than the refractive index of the second dielectric layer (eg, SiO ₂ film). The dielectric multilayer filter can suppress light in the second wavelength band due to interference of reflected light generated at the interface between the first dielectric layer and the second dielectric layer.

1.4. Emission Wavelength Band and Wavelength of Interest FIG. 6 shows an example of intensity characteristics of light emitted from the light emitting unit 14. In the example of FIG. 6, the intensity of light having a wavelength of 525 [nm] shows the maximum value, and the intensity of light having other wavelengths is normalized at that intensity. In the example of FIG. 6, the wavelength range (light emission wavelength band) of light emitted from the light emitting unit 14 is 485 [nm] to 575 [nm]. In the example of FIG. 6, the relative intensity of light having a wavelength in the range of 505 [nm] to 540 [nm] is 0.5 (= 50 [%]) or more. In other words, the half-value width of the light emitted from the light emitting unit 14 is 30 [nm]. The relative intensity of light having a wavelength in the range of 500 [nm] to 555 [nm] is 0.1 (= 10 [%]) or more. The wavelength of interest of light emitted from the light emitting unit 14 may be a maximum value of 525 [nm]. For example, a range of 500 [nm] to 555 [nm] may be set as the wavelength of interest of light emitted from the light emitting unit 14. . In short, the wavelength of interest λ0 is included in the emission wavelength band (λ01 to λ02) and is a wavelength at which the reflection intensity is changed by absorption at the detection site O (in a broad sense, a wavelength including biological information), And what is necessary is just the wavelength of the light which is not suppressed by the 1st, 2nd filters 15 and 19-1.

  In the transmission characteristics of the first filter 15 shown in FIG. 4, the transmittance of light in the wavelength band 500 [nm] to 555 [nm] around the wavelength of interest λ0 within the emission wavelength band is the first wavelength. It is 25% or higher, which is higher than the transmittance of the band (for example, 5 [%] or less), and the transmittance of light of the wavelength of interest λ0 is 40% or more. Further, in the transmission characteristics of the second filter 19-1 shown in FIG. 5A, the transmission of light in the wavelength band 500 [nm] to 555 [nm] centering on the wavelength of interest λ0 within the emission wavelength band. The rate is 85% or higher, which is higher than the transmittance of the second wavelength band (for example, 5 [%] or lower). Thus, both the first filter 15 and the second filter 19-1 can transmit part or all of the light in the emission wavelength band including at least the wavelength of interest λ 0 emitted from the light emitting unit 14. Since the light of the wavelength of interest λ0 transmitted through the first filter 15 is attenuated, as shown in FIG. 5A, the transmittance of the second filter 19-1 is high with respect to the wavelength of interest λ0. It is preferable to show the rate.

  The light emitting unit 14 is, for example, an LED, and the wavelength of light emitted from the LED is a maximum intensity (in a broad sense, in a wavelength range of 425 [nm] to 625 [nm] in which the detected site O exhibits light absorption characteristics. For example, green light is emitted. The thickness of the light emitting unit 14 is, for example, 20 [μm] to 1000 [μm].

1.5. FIG. 7 shows an example of sensitivity characteristics of light received by the light receiving unit 16. In the example of FIG. 7, the sensitivity of light having a wavelength of 875 [nm] shows the maximum value, and the sensitivity of light having other wavelengths is normalized by this sensitivity. In the example of FIG. 7, the light receiving unit 16 is a Si photodiode. The light receiving unit 16 is not limited to the example of FIG. 7, and may be another Si photodiode having a maximum sensitivity value (peak value in a broad sense) in a range of, for example, 800 [nm] to 1000 [nm]. Further, the light receiving unit 16 may be a photodiode such as a GaAsP photodiode having a maximum sensitivity value (peak value in a broad sense) in a range of 550 [nm] to 650 [nm], for example. The thickness of the light receiving unit 16 is, for example, 20 [μm] to 1000 [μm]. The Si photodiode is less expensive than the GaAsP photodiode, but senses infrared rays, so that not only the first filter 15 but also the second filter 19-1 is required.

  In the example of FIG. 7, the relative sensitivity of light having a wavelength of 1050 [nm] is 0.1 (= 10 [%]). The sensitivity wavelength band of the light receiving unit 16 can be set to a relative sensitivity of 0.1 or more, for example, and may be in a range of 380 [nm] to 1050 [nm]. The second wavelength band (filter band in a broad sense) of the second filter 19-1 may end at the upper limit (λmax = 1050 [nm]) of the sensitivity wavelength band of the light receiving unit 16.

1.6. Arrangement of First and Second Filters In the example of FIG. 1, both the first filter 15 and the second filter 19-1 are provided in the optical path between the detected portion O and the light receiving unit 16. . In the example of FIG. 1, the place where the external light R3 ′ (propagation light) is generated is different from the place where the reflected light R1 ′ is generated, but the external light R3 propagates to the inspection object near the detection site O. That is, external light R3 ′ (propagation light) can be suppressed by providing the first filter 15 and the second filter 19-1 in the optical path between the detected portion O and the light receiving unit 16. In the wrist-worn biological information detector, external light R3 such as external sunlight easily enters the biological information detector with the movement of the wrist during walking or the like, so the first filter 15 and the second filter 19 The presence of -1 is important.

  In the example of FIG. 1, the first filter 15 is disposed on the substrate 11, but may be disposed on the light receiving unit 16 or the reflecting unit 18. The first filter 15 may be disposed on all of the substrate 11, the light receiving unit 16, and the reflecting unit 18. When the first filter 15 is a resin sheet, it is easy to attach the resin sheet on the substrate 11. Further, the resin sheet can be arranged in a light transmission region where the light emitting unit 14 and the light receiving unit 16 do not exist in a plan view. Or a resin sheet can be arrange | positioned on the board | substrate 11 in which the light emission part 14 does not exist in planar view.

  When the first filter 15 is a dye absorption filter having the transmission characteristics shown in FIG. 4, the wavelength of interest of the light emitted from the light emitting unit 14 is transmitted through the first filter 15 and attenuated. Therefore, it is preferable that the first filter 15 is not provided in the optical path between the light emitting unit 14 and the detection site O. In other words, the first filter 15 is preferably disposed on at least one of the substrate 11, the light receiving unit 16, and the reflecting unit 18.

  In the example of FIG. 1, the second filter 19-1 is disposed at the contact portion 19. When the second filter 19-1 is a dielectric multilayer filter having the transmission characteristics shown in FIG. 5A, the wavelength of interest of the light emitted from the light emitting unit 14 is transmitted through the second filter 19-1, and is almost the same. Does not decay. Therefore, the second filter 19-1 can be provided in the optical path between the light emitting unit 14 and the detection site O. The contact portion 19 has a contact surface with the object to be inspected, and the contact surface is flat. When the second filter 19-1 is a dielectric multilayer filter, it is easy to stack the dielectric multilayer on the contact portion 19 having high flatness. In other words, the dielectric multilayer filter 19-1 that depends on the incident angle can more effectively suppress infrared rays as the flatness is higher. However, when the dielectric multilayer filter 19-1 is disposed on the contact surface of the contact portion 19, the performance of the dielectric multilayer filter deteriorates due to the influence of oil or the like of the object to be inspected. Therefore, the second filter 19-1 is preferably provided in the optical path between the detected site O and the light receiving unit 16 except for the contact surface of the contact unit 19. For example, as shown in FIG. 1, the second filter 19-1 is preferably disposed on a surface (facing surface) that faces the contact surface. Note that the second filter 19-1 may be disposed on the entire inner wall of the contact portion 19.

1.7. Another Configuration Example of the Biological Information Detector FIG. 8 shows another configuration example of the biological information detector of this embodiment. As shown in FIG. 8, the light transmission film 11-1 can be formed on the first surface (for example, the front surface) of the substrate 11 and the second surface (for example, the back surface) opposite to the first surface. . Moreover, the same code | symbol is attached | subjected about the structure same as the structural example mentioned above, and the description is abbreviate | omitted. The light transmission film 11-1 may be formed only on the first surface, or may be formed only on the second surface. In the example of FIG. 4, the light transmission film 11-1 is formed in the light transmission region of the substrate 11 where the light emitting unit 14 and the light receiving unit 16 are not disposed. The light transmission film 11-1 can be composed of, for example, a solder resist (resist in a broad sense). The first filter 15 can be pasted on the light transmission film 11-1 formed on the second surface (for example, the back surface) of the substrate 11.

  In the example of FIG. 8, the wiring to the light emitting unit 14 and the wiring to the light receiving unit 16 are omitted, but the first surface and the second surface of the substrate 11 are not peeled off so that the wiring on the substrate 11 is not peeled off. Can be roughened. Therefore, by forming the light transmission film 11-1 on the first surface and the second surface, the rough surface of the surface of the substrate 11 is filled with the light transmission film, and the flatness of the entire substrate 11 is improved. In other words, since the light transmission film 11-1 on the substrate 11 is flat, when light passes through the substrate 11, the diffusion of light on the rough surface of the surface of the substrate 11 can be reduced. In other words, the transmittance of the substrate 11 is improved by the presence of the light transmission film 11-1. Accordingly, the amount of light reaching the light receiving unit 16 is increased, and the detection accuracy of the biological information detector is further improved.

  The refractive index of the light transmission film 11-1 is preferably between the refractive index of air and the refractive index of the substrate 11. Furthermore, the refractive index of the light transmission film 11-1 is preferably closer to the refractive index of the substrate 11 than the refractive index of air. In such a case, reflection of light at the interface can be reduced.

1.8. FIG. 9 shows an example of light transmission characteristics through the substrate 11 coated with the light transmission film 11-1. In the example of FIG. 9, the transmittance is calculated using the intensity of light before passing through the substrate 11 and the intensity of light after passing through the substrate 11. In the example of FIG. 9, the transmittance of light having a wavelength of 525 [nm] shows a maximum value in a wavelength region of 700 [nm] or less, which is the lower limit of the biological window. Alternatively, in the example of FIG. 9, the maximum value of the transmittance of light passing through the light transmission film 11-1 in the wavelength region of 700 nm or less, which is the lower limit of the biological window, is the wavelength of light emitted by the light emitting unit 14. It may be within a range of ± 10% of the maximum value of intensity. In this way, the light transmission film 11-1 selectively emits light (for example, the first light R1 in FIG. 8 (reflected light R1 ′ of the first light R1 in a narrow sense)) emitted from the light emitting unit 14. It is preferable to transmit. The presence of the light transmission film 11-1 can improve the flatness of the substrate 11 and can prevent a decrease in the efficiency of the light receiving unit 16 to some extent. As shown in the example of FIG. 9, for example, in the visible light region, when the transmittance of light having a wavelength of 525 [nm] shows a maximum value (peak value in a broad sense), the light transmitting film 11- 1 indicates, for example, green.

  FIG. 10 shows an appearance example of the light transmission film 11-1 in FIG. As shown in FIG. 10, the substrate 11 on which the light transmission film 11-1 is formed has a rectangular shape in plan view (for example, on the light receiving unit 16 side in FIG. 8). In the example of FIG. 10, the light receiving unit 16 is placed on the first surface (for example, the surface) of the substrate 11. The light transmission film 11-1 can be formed in the region of the first surface of the substrate 11 where the light receiving unit 16 is not placed.

  Specifically, on the first surface of the substrate 11, for example, a wiring 61 for connecting to the anode of the light receiving unit 16 is also formed, and for example, a wiring 62 for connecting to the cathode of the light receiving unit 16 is also formed. It is formed. In the example of FIG. 10, the wiring 61 is connected to the anode of the light receiving unit 16 via, for example, a bonding wire 61-1, and the wiring 62 is directly connected to the cathode of the light receiving unit 16. After the wiring 61 and the wiring 62 are formed on the substrate 11, the light transmission film 11-1 can be applied on the first surface of the substrate 11. That is, the light transmission film 11-1 may be formed on the wiring 61 and the wiring 62. However, the light transmission film 11-1 may be selectively applied only to the region (light transmission region) of the substrate 11 where the light receiving unit 16 and the wiring 61 and the wiring 62 are not placed.

  Thereafter, the reflection portion 18 can be formed or fixed on the substrate 11 (and the light transmission film 11-1). As shown in FIG. 6, in a plan view, the outer shape of the reflection portion 18 is a quadrangle, and the boundary 18-1 between the reflection surface (dome surface) of the reflection portion 18 and the substrate 11 (light transmission film 11-1). The outer shape of this indicates a circle. Alternatively, the light transmission film 11-1 may be selectively applied only to the light transmission region inside the boundary 18-1 (circular). In other words, the light transmission film 11-1 may be selectively applied only to a light transmission region through which light received by the light receiving unit 16 is transmitted.

  In the example of FIG. 10, the light emitting unit 14 is placed on the second surface (for example, the back surface) of the substrate 11. Similar to the first surface, the light transmission film 11-1 can be formed in a region of the second surface of the substrate 11 where the light emitting unit 14 is not placed. The light transmissive film 11-1 is preferably formed at least in a light transmissive region (light transmissive region through which light emitted from the light emitting unit 14 is transmitted). In the example of FIG. 10, the wiring 63 is formed on the first surface at the end 11-2 of the substrate 11, penetrates the substrate 11, and is formed on the second surface. The wiring 64 is also formed on the first surface at the end portion 11-2 of the substrate 11, penetrates the substrate 11, and is formed on the second surface. The wiring 63 is connected to the cathode of the light emitting unit 14 on the second surface side through, for example, a bonding wire 63-1, and the wiring 64 emits light on the second surface side through, for example, the bonding wire 64-1. It is connected to the anode of the section 14. Further, by projecting the end portion 11-2 of the substrate 11 sandwiched between the reflecting portion 18 and the contact portion 19 to the outside, the wiring to the light emitting portion 14 and the light receiving portion 16 can be easily taken out to the outside. it can.

  FIG. 11 shows an example of storing the substrate 11. In the example of FIG. 11, the board | substrate 11 can be comprised with a flexible substrate. Accordingly, the end portion 11-2 of the substrate 11 can be bent. As shown in FIG. 11, the board 11 can be connected to a computer motherboard (for example, a main board constituting a biological information measuring device described later) 82 with the end portion 11-2 of the board 11 being bent. it can. In other words, a small biological information detector can be provided by bending the substrate 11. In FIG. 11, the light transmission film 11-1 is omitted. Further, the light emitting unit 14 and the light receiving unit 16 are also omitted. The wiring to the light emitting unit 14 and the wiring to the light receiving unit 16 can be formed on the substrate 11 as shown in FIG. 10, for example, and the wiring is connected to the control circuit on the motherboard 82 and the light emitting unit 14 via the connector 84. And the light receiving unit 16 can be connected.

  The substrate 11 is sandwiched between the reflecting portion 18 and the contact portion 19, whereby the reflecting portion 18 is fixed to the substrate 11. In the space formed by the reflecting surface of the reflecting portion 18 and the substrate 11, either the light emitting portion 14 or the light receiving portion 16 can be arranged. The substrate 11 to which the reflecting portion 18 is fixed cannot be locally bent, while the end portion 11-2 of the substrate 11 to which the reflecting portion 18 is not fixed can be bent. Since the substrate 11 is sandwiched between the reflecting portion 18 and the contact portion 19, even if the substrate 11 itself is a flexible substrate, the light emitting portion 14 and the light receiving portion 16 are mounted and supported on the substrate 11. be able to.

1.9. Still Another Configuration Example of the Biological Information Detector FIG. 12 shows still another configuration example of the biological information detector of the present embodiment. As shown in FIG. 12, the biological information detector can include a reflection unit 92 that reflects light. In the following description, the reflecting portion 92 is referred to as a first reflecting portion, and the reflecting portion 18 in FIG. 1 is referred to as a second reflecting portion. Moreover, the same code | symbol is attached | subjected about the structure same as the structural example mentioned above, and the description is abbreviate | omitted. In the example of FIG. 12, after the light transmission film 11-1 is formed on the substrate 11, the first reflection unit 92 and the light receiving unit 16 are disposed.

  In the example of FIG. 12, the biological information detector includes a light emitting unit 14, a first reflecting unit 92, a light receiving unit 16, and a second reflecting unit 18. The light emitting unit 14 emits the first light R1 directed to the detection site O of the object to be inspected (for example, a user) and the second light R2 directed to a direction different from the detection site O (the first reflection unit 92). To emit. The first reflecting portion 92 reflects the second light R2 and guides it to the detection site O. The light receiving unit 16 receives light R1 'and R2' (reflected light) having biological information, in which the first light R1 and the second light R2 are reflected by the detection site O. The second reflecting unit 18 reflects and guides the light R1 ′ and R2 ′ (reflected light) having biological information from the detection site O to the light receiving unit 16. Due to the presence of the first reflecting portion 92, the second light R <b> 2 that does not directly reach the detection site O of the inspection object (user) also reaches the detection site O. In other words, the amount of light that reaches the detection site O via the first reflecting portion 92 increases, and the efficiency of the light emitting portion 14 increases. Therefore, the detection accuracy (S / N ratio) of the biological information detector is improved.

  In the example of FIG. 12, the second light R <b> 2 proceeds to the inside of the object to be inspected, and the reflected light R <b> 2 ′ at the detection site O travels to the second reflection unit 18. The biological information (pulse rate) is also reflected in the reflected light R2 'at the detection site O. In the example of FIG. 9, the first light R1 is partially reflected by the surface (skin surface) SA of the object to be inspected. When the detection site O is inside the inspection object, the biological information (pulse rate) is not reflected in the reflected light R1 ″ (direct reflection light) on the surface SA of the inspection object.

  In the example of FIG. 12, the light emitting unit 14 may have a first light emitting surface 14 </ b> A that faces the detected site O and emits the first light R <b> 1. In addition, the light emitting unit 14 may further include a second light emitting surface 14B that emits the second light R2 that is the side surface of the first light emitting surface 14A. In this case, the first reflecting portion 92 can have a wall portion surrounding the second light emitting surface 14B, and the wall portion reflects the second light R2 toward the detection site O. A reflective surface (corresponding to reference numeral 92-2 shown in FIGS. 13A to 13C) can be provided. The second light R2 is not necessarily emitted from the second light emitting surface 14B. In short, the first reflecting surface (reference numeral 92-2 in FIGS. 13A to 13C) is light other than light (second light R2) directed directly from the light emitting unit 14 toward the detection site O. ) Is reflected and guided to the detection site O.

  The wall portion of the first reflecting portion 92 reflects light that does not have biological information (ineffective light: noise) reflected by the surface of the object to be inspected, so that light that does not have biological information is transmitted to the light receiving portion 16. A second reflecting surface that suppresses incidence (corresponding to reference numeral 92-3 shown in FIGS. 13A and 13C) can be further included.

  Moreover, the contact part 19 can ensure the clearance gap (for example, (DELTA) h2) between the 1st reflection part 92 and the to-be-detected site | part O. FIG. Furthermore, there is a gap (for example, Δh2 ′) between the first reflecting portion 92 and the contact portion 19.

  When the maximum value of the length of the first reflecting portion 92 in the direction parallel to the first surface of the substrate 11 in the cross-sectional view is W1, and the maximum value of the length of the light receiving portion 16 in that direction is W2, W1 ≦ W2 can be satisfied. The substrate 11 transmits the reflected light R1 'of the first light R1 emitted to the detection site O and the like. By making the maximum value W1 of the length of the first reflecting portion 92 equal to or less than the maximum value W2 of the length of the light receiving portion 16, the amount of light reaching the second reflecting portion 18 can be increased. In other words, the maximum value W1 of the length of the first reflecting portion 92 can be set so that the first reflecting portion 92 does not block or reflect the reflected light R1 'at the detection site O.

  FIG. 13A, FIG. 13B, and FIG. 13C show configuration examples of the first reflecting portion 92 of FIG. As shown in FIG. 13A, the first reflecting portion 92 includes a support portion 92-1 that supports the light emitting portion 14, and an inner wall surface 92 of the wall portion that surrounds the second light emitting surface 14B of the light emitting portion 14. -2 and top surface 92-3. In FIGS. 13A to 13C, the light emitting unit 14 is omitted. In the example of FIG. 13A, the first reflecting portion 92 can reflect the second light R2 on the detected portion O on the inner wall surface 92-2 (see FIG. 12), and the inner wall surface 92-2. Has a first reflecting surface. The thickness of the support portion 92-1 is, for example, 50 [μm] to 1000 [μm], and the thickness of the wall portion (92-3) is, for example, 100 [μm] to 1000 [μm].

  In the example of FIG. 13A, the inner wall surface 92-2 has a height direction (first direction) as the position is farther from the center of the first reflecting portion 92 in the width direction (first direction) in a cross-sectional view. And a slope (92-2) that is displaced toward the detected site O in the direction orthogonal to the direction). The slope (92-2) in FIG. 13A is formed as an inclined plane in a cross-sectional view, but may be a slope such as a curved surface shown in FIG. 13C, for example. The inner wall surface 92-2 may be formed of a plurality of inclined planes having different inclination angles, or may be formed of a curved surface having a plurality of curvatures. When the inner wall surface 92-2 of the first reflecting portion 92 has an inclined surface, the inner wall surface 92-2 of the first reflecting portion 92 can reflect the second light R2 toward the detection site O. it can. In other words, the slope of the inner wall surface 92-2 of the first reflecting portion 92 can be said to be a first reflecting surface with improved directivity of the light emitting portion 14. In such a case, the amount of light that reaches the detection site O further increases. Moreover, you may abbreviate | omit top surface 92-3 of FIG. 13 (A) and FIG.13 (C), for example, as FIG.13 (B) shows. When the first reflecting portion 92 has the top surface 92-3, the reflected light R1 '' (directly reflected light) on the surface SA of the object to be inspected can be reflected to the detection site O or its periphery, The reflected light R1 ″ is suppressed from reaching the light receiving unit 16 (see FIG. 12). That is, the top surface 92-3 in FIGS. 13A and 13C reflects the directly reflected light (in a broad sense, noise) that attempts to reach the second reflecting portion 18 and the light receiving portion 16. It can be said that the second reflecting surface reduces noise. In FIGS. 13A to 13C, a range indicated by reference numeral 92-4 functions as a mirror surface portion.

  In the example of FIG. 12, the first reflecting portion 92 is, for example, given on the basis of the surface of the light emitting portion 14 (for example, the first light emitting surface 14A) that defines the shortest distance from the surface SA of the object to be inspected. The height Δh1 (for example, Δh1 = 50 [μm] to 950 [μm]) may be projected toward the detected portion O. In other words, the gap between the first reflecting portion 92 and the surface SA of the object to be inspected (rather than the gap (for example, Δh0 = Δh1 + Δh2) that is the shortest distance between the light emitting unit 14 and the surface SA of the object to be inspected). For example, Δh2 = Δh0−Δh1 = 200 [μm] to 1200 [μm]) can be reduced. Therefore, for example, the first reflecting portion 92 increases the area of the first reflecting surface (92-2) due to the presence of the protrusion amount Δh1 from the light emitting portion 14, and increases the amount of light reaching the detection site O. be able to. Further, the reflected light at the detection site O reaches the second reflection unit 18 from the detection site O due to the presence of the gap Δh2 between the first reflection unit 92 and the surface SA of the inspection object. An optical path can be secured. Moreover, when the 1st reflection part 92 has a 2nd reflective surface (92-3), the light (effective light) which has biological information, and the light which does not have biological information by adjusting (DELTA) h1 and (DELTA) h2. The amount of (invalid light: noise) incident on the light receiving unit 16 can be adjusted, and thereby the S / N can be further improved.

  FIG. 14A and FIG. 14B show an external appearance example of the first reflecting portion 92 and the light emitting portion 14 of FIG. 12 in plan view. In the example of FIG. 14A, the outer periphery of the first reflecting portion 92 represents a circle in a plan view (for example, on the detected site O side in FIG. 12), and the diameter of the circle is, for example, 200 [Μm] to 11000 [μm]. In the example of FIG. 14 (A), the wall part (92-2) of the 1st reflection part 92 surrounds the light emission part 14 (refer FIG. 12, FIG. 13 (A)). Further, the outer periphery of the first reflecting portion 92 may represent a quadrangle (in the narrow sense, a square) as shown in FIG. In the examples of FIGS. 14A and 14B, the outer periphery of the light-emitting portion 14 is square (in the narrow sense, square) in plan view (for example, on the detected site O side in FIG. 12). And one side of the square is, for example, 100 [μm] to 10000 [μm]. Further, the outer periphery of the light emitting unit 14 may represent a circle.

  The first reflecting portion 92 is formed of a metal and has a mirror-finished surface to have a reflecting structure (in a narrow sense, a mirror reflecting structure). In addition, the 1st reflection part 92 may be formed, for example with resin, and the surface may be mirror-finished. Specifically, for example, a base metal of the first reflecting portion 92 is prepared, and then the surface thereof is plated, for example. Alternatively, for example, a thermoplastic resin is filled in a mold (not shown) of the first reflecting portion 92 and molded, and then, for example, a metal film is deposited on the surface.

  In the example of FIGS. 14A and 14B, the first reflecting portion 92 is a region other than the region that directly supports the light emitting portion 14 in a plan view (for example, on the detected site O side in FIG. 12). (A part of the support portion 92-1, the inner wall surface 92-2 and the top surface 92-3 of the wall portion) are exposed. This exposed region is shown as a mirror surface portion 92-4 in the example of FIG. In the example of FIG. 13A, the dotted line representing the mirror surface portion 92-4 is located inside the first reflecting portion 92, but actually, the mirror surface portion 92-4 is It is formed on the surface of the reflecting portion 92.

  In the examples of FIGS. 13A, 13B, and 13C, the mirror surface portion 92-4 preferably has a high reflectance. The reflectance of the mirror surface portion 92-4 is, for example, 80% to 90% or more. Further, the mirror surface portion 92-4 can be formed only on the slope of the inner wall surface 92-2. When the mirror surface portion 92-4 is formed not only on the slope of the inner wall surface 92-2 but also on the support portion 92-1, the directivity of the light emitting portion 14 is further increased. When the mirror surface portion 92-4 is formed on the top surface 92-3, the first reflecting portion 92 is reflected light R1 ″ (directly on the surface SA of the object to be inspected, for example, as shown in FIG. (Reflected light: ineffective light) can be reflected to the detected portion O or its periphery, and the reflected light R1 ″ is suppressed from reaching the second reflecting portion 18 and the light receiving portion 16. Since the directivity of the light emitting unit 14 is increased and the directly reflected light (noise in a broad sense) is reduced, the detection accuracy of the biological information detector is improved.

  FIG. 15 shows an example of the appearance of the light receiving unit 16 in FIG. In the example of FIG. 15, in plan view (for example, on the second reflecting portion 18 side in FIG. 12), the outer periphery of the light receiving portion 16 represents a quadrangle (in the narrow sense, a square), and one side of the square is For example, it is 100 [μm] to 10000 [μm]. Moreover, the outer periphery of the 1st reflection part 92 represents a circle in planar view (for example, the 2nd reflection part 18 side of FIG. 9). The outer periphery of the first reflecting portion 92 may represent a quadrangle (square in a narrow sense) as in the example of FIG. Further, the outer periphery of the light receiving unit 16 may represent a circle.

  In the example of FIG. 15, if the maximum value of the length of the first reflecting portion 92 is W1 and the maximum value of the length of the light receiving portion 16 is W2, as indicated by a line segment AA ′, W1 ≦ The relational expression of W2 can be satisfied. A sectional view taken along line A-A ′ in FIG. 15 corresponds to FIG. 12. In the sectional view using the line segment B-B ′ in FIG. 12, the maximum value W1 of the length of the first reflecting portion 92 is larger than the minimum value of the length of the light receiving portion 16. The maximum value W1 of the length of the first reflecting portion 92 may be set to be equal to or less than the minimum value of the length of the light receiving portion 16, but the efficiency of the first reflecting portion 92 (in a broad sense, the light emitting portion 14). Efficiency) decreases. In the example of FIG. 15, the maximum value W1 of the length of the first reflecting portion 92 is the maximum length of the light receiving portion 16 so that the reflected light R1 ′ is not blocked or reflected while maintaining the efficiency of the light emitting portion 14. The maximum value W1 of the length of the first reflecting portion 92 is set to be equal to or less than the value W2, and is set to be larger than the minimum value of the length of the light receiving portion 16.

2. Biological Information Measuring Device FIGS. 16A and 16B are external views of a biological information measuring device including the biological information detector shown in FIG. As shown in FIG. 16A, for example, the biological information detector of FIG. 1 further includes a wristband 150 that can attach the biological information detector to an arm (a wrist in a narrow sense) of a subject (user). Can be included. In the example of FIG. 16A, the biological information is a pulse rate, for example, “72”. In addition, the biological information detector is incorporated in a wristwatch, and the time (for example, 8:15 am) is shown. Further, as shown in FIG. 16B, an opening is provided in the back cover of the wristwatch, and for example, the contact portion 19 of FIG. 1 is exposed in the opening. In the example of FIG. 16B, the second reflecting portion 18 and the light receiving portion 16 are incorporated in a wristwatch. In the example of FIG. 16B, the first reflecting portion 92, the light emitting portion 14, the wristband 150, and the like are omitted.

  FIG. 17 shows a configuration example of the biological information measuring apparatus. The biological information measuring device includes a biological information detector shown in FIG. 1 and the like and a biological information measuring unit that measures biological information from a light reception signal generated in the light receiving unit 16 of the biological information detector. As shown in FIG. 17, the biological information detector can include a light emitting unit 14, a light receiving unit 16, and a control circuit 161 for the light emitting unit 14. The biological information detector can further include an amplification circuit 162 for the light reception signal of the light receiving unit 16. In addition, the biological information measurement unit can include an A / D conversion circuit 163 that performs A / D conversion on the light reception signal of the light receiving unit 16 and a pulse rate calculation circuit 164 that calculates a pulse rate. The biological information measurement unit may further include a display unit 165 that displays the pulse rate.

  The biological information detector can include an acceleration detection unit 166, and the biological information measurement unit performs an A / D conversion circuit 167 that performs A / D conversion on a light reception signal of the acceleration detection unit 166, and digital signal processing that processes a digital signal. A circuit 168 can be further included. The configuration example of the biological information measuring device is not limited by FIG. The pulse rate calculation circuit 164 in FIG. 17 may be, for example, an MPU (Micro Processing Unit) of an electronic device incorporating a biological information detector.

  The control circuit 161 in FIG. 17 drives the light emitting unit 14. The control circuit 161 is, for example, a constant current circuit, and supplies a given voltage (for example, 6 [V]) to the light emitting unit 14 via a protective resistor, and the current flowing through the light emitting unit 14 is given a given value ( For example, 2 [mA]) is maintained. The control circuit 161 can drive the light emitting unit 14 intermittently (for example, at 128 [Hz]) in order to reduce current consumption. The control circuit 161 is formed on, for example, the mother board 82 in FIG. 11, and the wiring between the control circuit 161 and the light emitting unit 14 is formed on, for example, the substrate 11 in FIG.

  17 can remove a direct current component from the light reception signal (current) generated in the light receiving unit 16, extract only the alternating current component, amplify the alternating current component, and generate an alternating current signal. . The amplifying circuit 162 removes a DC component having a frequency lower than a given frequency by using, for example, a high-pass filter, and buffers the AC component by using, for example, an operational amplifier. The received light signal includes a pulsation component and a body motion component. The amplifier circuit 162 or the control circuit 161 can supply a power supply voltage for operating the light receiving unit 16 with, for example, a reverse bias to the light receiving unit 16. When the light emitting unit 14 is driven intermittently, the power of the light receiving unit 16 is also intermittently supplied, and the AC component is also intermittently amplified. The amplifier circuit 162 is formed, for example, on the mother board 82 in FIG. 11, and the wiring between the amplifier circuit 162 and the light receiving unit 16 is formed, for example, on the substrate 11 in FIG. In addition, the amplifier circuit 162 may include an amplifier that amplifies the received light signal before the high-pass filter. When the amplifier circuit 162 includes an amplifier, the amplifier is formed at, for example, the end 11-2 of the substrate 11 in FIG.

  The A / D conversion circuit 163 in FIG. 17 converts the AC signal generated in the amplifier circuit 162 into a digital signal (first digital signal). The acceleration detection unit 166 in FIG. 17 detects, for example, three-axis (X-axis, Y-axis, and Z-axis) accelerations, and generates an acceleration signal. The movement of the body (arm), and hence the movement of the biological information measuring device, is reflected in the acceleration signal. The A / D conversion circuit 167 in FIG. 17 converts the acceleration signal generated by the acceleration detection unit 166 into a digital signal (second digital signal).

  The digital signal processing circuit 168 in FIG. 17 uses the second digital signal to remove or reduce the body motion component of the first digital signal. The digital signal processing circuit 168 can be configured by an adaptive filter such as an FIR filter, for example. The digital signal processing circuit 168 inputs the first digital signal and the second digital signal to the adaptive filter, and generates a filter output signal in which noise is removed or reduced.

  The pulse rate calculation circuit 164 in FIG. 17 analyzes the frequency of the filter output signal by, for example, fast Fourier transform (diffusion Fourier transform in a broad sense). The pulse rate calculation circuit 164 specifies the frequency representing the pulsation component based on the result of the frequency analysis, and calculates the pulse rate.

  18A and 18B show another configuration example of the biological information detector of the present embodiment. The biological information detector of FIG. 1 and the like includes the first filter 15 and the second filter 19-1, but as shown in FIGS. 18A and 18B, the living body information detector The light R3 ′ (propagating light) may pass through the first filter 15 and the second filter 19-1 and reach the light receiving unit 16. Since the external light R3 is diffused or scattered inside the object to be inspected, for example, at a place where there are no obstacles such as tendons and bones, the noise information is reflected in the propagation light R3 'propagated through the object to be inspected. When the influence of the propagation light R3 ′ propagated through the body to be inspected cannot be ignored, the biological information detector can include a second light receiving unit 16 ′ as shown in FIGS. 18 (A) and 18 (B). .

  When the light receiving unit 16 is called a detection sensor unit (first sensor unit), the second light receiving unit 16 'can be called a correction sensor unit (second sensor unit). As shown in FIG. 18A, the first filter 15, the second filter 19-1, and the contact portion 19 can also be provided in the correction sensor portion. When the first filter 15 and the second filter 19-1 are not provided in the correction sensor unit, the difference between the first noise information received by the light receiving unit 16 and the second noise information received by the second light receiving unit 16 ′. There is a problem that becomes large.

  Since the propagation light R3 ′ propagated through the inspected body reaches both the light receiving unit 16 and the second light receiving unit 16 ′ under substantially the same conditions, the living body information detector reflects as shown in FIG. 18 (A). Part 18 'can be included. The reflection unit 92, the reflection unit 18, and the reflection unit 18 'can be referred to as a first reflection unit, a second reflection unit, and a third reflection unit, respectively. Since the propagation light R3 ′ propagated through the inspected body actually enters the biological information detector from many directions, the presence of the first reflecting section 92 and the presence of the light emitting section 14 cause the inspected body to be inspected. A part of the propagated propagation light R 3 ′ may be blocked or reflected by the first reflecting unit 92 and the light emitting unit 14. Assuming that the area of the reflecting surface (dome surface) of the second reflecting portion 18 is S1, and the area of the reflecting surface of the third reflecting portion 18 ′ is S2, S2 <S1 as in the example of FIG. It is preferable that the relational expression is satisfied. When the relational expression S2 <S1 is satisfied, the propagation light R3 ′ that has propagated through the inspected object by the amount of the reduction in the area of the reflection surface of the third reflection portion 18 ′ (= S1−S2) is changed to the third reflection portion. Reaching 18 ′ can be suppressed. For example, by making the radius of the circular arc or the parabolic focal length defining the reflective surface of the third reflective portion 18 ′ smaller than the radius of the circular arc or the parabolic focal length defining the reflective surface of the second reflective portion 18. , S2 <S1 may be satisfied.

  When the second reflecting portion 18 and the third reflecting portion 18 ′ are referred to as a synthetic reflecting portion, the second reflecting portion 18 and the third reflecting portion 18 ′ are formed as a single unit as shown in FIG. You may comprise by a synthetic | combination reflection part. Further, the single contact portion 19 (synthetic contact portion) shown in FIG. 18 (A) may be composed of the contact portion 19 and the second contact portion 19 'as shown in FIG. 18 (B). Note that the configuration example of the biological information measurement device is not limited to FIGS. 18A and 18B.

  FIG. 19 shows a connection example of the light receiving unit 16 and the second light receiving unit 16 ′. As shown in FIG. 19, the anode of the light receiving unit 16 is connected to the cathode of the second light receiving unit 16 ′ to form a combined light receiving unit 16 ″. However, the anode of the light receiving unit 16 is made independent of the cathode of the second light receiving unit 16 ′, and a signal (detected light reception signal) generated in the light receiving unit 16 is a signal generated in the second light receiving unit 16 ′ ( The correction light reception signal may be taken out independently.

  In the example of FIG. 19, the combined light receiving unit 16 ″ outputs a light reception signal indicating a difference between the detected light reception signal and the corrected light reception signal. The detected light reception signal generated in the light receiving unit 16 includes biological information caused by light emitted from the light emitting unit 14 and noise information caused by external light, and the corrected light reception signal generated in the second light receiving unit 16 ′ is Since noise information resulting from external light is included, the received light signal indicating the difference between the detected received light signal and the corrected received light signal can represent only biological information resulting from the light emitted from the light emitting unit 14. In other words, the synthesized biological information from the light receiving unit 16 (biological information at the detection site O and first noise information resulting from the external light R3) is converted into noise information (external light R3 from the second light receiving unit 16 ′). The second noise information) can be corrected. By correcting or canceling the first noise information with the second noise information, the detection accuracy of the biological information detector is further improved.

  In addition, as shown in the example of FIG. 19, a bipolar transistor (in a broad sense, an amplifier 184) for amplifying the light reception signal of the combined light receiving unit 16 '' based on the input may be added. Further, a resistor 186 may be added between the anode of the light receiving unit 16 and the cathode of the second light receiving unit 16 '.

  Although the present embodiment has been described in detail as described above, it will be easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term described with a different term having a broader meaning or the same meaning at least once in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings.

11 substrate, 11-1 light transmission film, 11-2 end, 14 light emitting part,
14A 1st light emission surface, 14B 2nd light emission surface, 15 1st filter,
16 light receiving section, 16 'second light receiving section, 16''composite light receiving section,
18 reflective part (second reflective part), 18 'reflective part (third reflective part),
19 contact part, 19-1 2nd filter, 61, 62, 63, 64 wiring,
61-1, 63-1, 64-1 Bonding wire, 82 Motherboard,
84 connector, 92 reflection part (first reflection part), 92-1 support part,
92-2 inner wall surface (first reflective surface), 92-3 top surface (second reflective surface),
92-4 mirror surface part, 150 wristband, 161 control circuit,
162 amplification circuit, 163, 167 A / D conversion circuit, 164 pulse rate calculation circuit,
165 display unit, 166 acceleration detection unit, 168 digital signal processing circuit,
DR1 first direction, DR2 second direction, O detected site, R1 first light,
R2 second light, R3 outside light, R1 ′, R2 ′ reflected light (effective light),
R1 ″ directly reflected light (ineffective light), R3 ′ propagated light (noise),
SA surface of the object to be inspected, W1 maximum length of the first reflecting portion,
W2 Maximum length of light receiving part, Δh distance, Δh0, Δh1 height,
Δh2, Δh2 'clearance

Claims (8)

A light emitting unit that emits light in an emission wavelength band including a wavelength of interest toward a detection site of the object to be inspected,
A light-receiving unit that has sensitivity to a light-receiving wavelength band including the light-emitting wavelength band, and that receives light having biological information, in which light emitted from the light-emitting unit is reflected at the detection site;
A first filter provided between the detected part and the light receiving unit;
A second filter provided between the detected part and the light receiving unit,
The first filter transmits light of the wavelength of interest, suppresses light of a first wavelength band in the light receiving wavelength band higher than the wavelength of interest, and the first wavelength band is a first wavelength band A band from a wavelength to a second wavelength higher than the first wavelength, and the first wavelength is between the distal side of the detection site and the central side of the detection site within the subject. The increase characteristic of the intensity of external light propagating through the first wavelength is equal to or less than the wavelength of the transition point at which the first gradient shifts to the second gradient that is steeper than the first gradient.
The second filter transmits light of the wavelength of interest, suppresses light of a second wavelength band within the light receiving wavelength band, and the second wavelength band is at least from the second wavelength, A wrist-worn biological information detector characterized by having a band higher than the second wavelength and up to a third wavelength equal to or greater than the light receiving wavelength band. In claim 1,
The wrist-mounted biological information detector, wherein the first filter is a dye absorption filter. In claim 1 or 2,
The wrist-worn biological information detector, wherein the second filter is a dielectric multilayer filter. In any one of Claims 1 thru | or 3,
A substrate that is made of a material that is transparent to the wavelength of interest, the light emitting unit is disposed on a first surface, and the light receiving unit is disposed on a second surface opposite to the first surface;
A reflective portion that is disposed on the second surface side with respect to the substrate, has a reflective surface, and reflects light having the biological information by the reflective surface;
A contact portion disposed on the first surface side with respect to the substrate, made of a material transparent to the wavelength of interest, and having a contact surface with the object to be inspected;
And a wrist-worn biological information detector. In claim 4,
The wrist-mounted biological information detector, wherein the first filter is disposed on at least one of the substrate, the light receiving unit, and the reflecting unit. In claim 4 or 5,
The wrist-worn biological information detector, wherein the second filter is provided on at least one of the substrate, the light receiving unit, the reflecting unit, and the contact unit except the contact surface. In any one of Claims 1 thru | or 6,
The wrist-worn biological information detector, wherein the wavelength of the change point is in the range of 565 nm to 595 nm. The biological information detector according to any one of claims 1 to 7,
A biological information measuring unit that measures the biological information from a light reception signal generated in the light receiving unit,
The wrist-worn type biological information measuring device, wherein the biological information is a pulse rate.

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