Reflection type optical sensor

Abstract

To provide a reflection type optical sensor with a simple structure in which noise by the light from a measurement object surface is reduced.SOLUTION: In a reflection type optical sensor 10 including a base material 11, a light emission element 12 and a light reception element 13 provided on the base material 11, and a light shielding wall 14 provided between the light emission element 12 and the light reception element 13, the relationships between a distance de between the light emission element 12 and the light shielding wall 14, a distance dr between the light reception element 13 and the light shielding wall 14, and a thickness t of the light shielding wall 14 satisfy a formula of de+dr<t, and a shortest distance between a region that belongs to neither a region where the light emitted from the light emission element 12 does not reach a measurement object nor a region where reflected light of the light emitted from the measurement object or scattered light from the measurement object is not input into the light reception element 13, and a sensor surface where the reflection type optical sensor 10 and the measurement object come in contact with each other is 0.2-0.3 mm inclusive.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a reflective optical sensor. [Background technology]

[0002] 2. Description of the Related Art Known examples of devices that use a reflective optical sensor to optically and non-invasively detect biological information include pulse oximeters that measure blood oxygen saturation and blood glucose meters that measure blood glucose concentrations. In such a reflective optical sensor, light is emitted from a light-emitting element such as a light-emitting diode (LED) onto a fingertip or the like, and the reflected light from the living body being measured (specifically, the blood in the blood vessels) is received by a light-receiving element such as a photodiode, thereby detecting biological information as a change in the amount of received light.

[0003] As a photoreflector having two light-emitting elements and one light-receiving element in the same package, Patent Document 1 reports a photosensor having a photoreflector having a light-emitting element (12) and a light-receiving element (13) mounted on a substrate (11), a light-transmitting resin (15) that seals each of these elements, and a light-shielding resin (2) as shown in FIG. 8, in which a light-shielding wall (2a) is formed between the light-emitting element (12) and the light-receiving element (13), and a canopy (2b) is formed that is connected to the light-shielding wall (2a) and narrows the light-emitting surface above the light-emitting element (12). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 094089 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the photoreflector described in the conventional Patent Document 1, although it is designed to effectively irradiate the blood flowing in the blood vessels in the living body to be measured by restricting the emission angle of light irradiation from the light-emitting element by means of a shield, since the incident angle of light received by the light-receiving element is not restricted, signals from the surface of the living body are also detected, and such signals become noise.

[0006] An object of the present invention is to solve the above-described conventional problems and achieve the following object. That is, an object of the present invention is to provide a reflection-type optical sensor having a simple structure with reduced noise due to light from the surface of the measurement object.

Means for Solving the Problems

[0007] Means for solving the above problems are as follows. That is, <1> A base material, A light-emitting element and a light-receiving element provided on the base material, A reflection-type optical sensor having a light-shielding wall provided between the light-emitting element and the light-receiving element, wherein The distance d between the light-emitting element and the light-shielding wall e And the distance d between the light-receiving element and the light-shielding wall r And the thickness t of the light-shielding wall satisfy the following formula: d e +d r <t, and The shortest distance between the region where the light emitted from the light-emitting element does not reach the measurement object and the region where the reflected light of the light emitted from the measurement object or the scattered light from the measurement object is not input to the light-receiving element, and the sensor surface where the reflection-type optical sensor and the measurement object are in contact is 0.2 mm or more and 0.3 mm or less. A reflection-type optical sensor characterized by this. <2> The light-emitting element is two or more light-emitting elements provided adjacent to each other, The reflection-type optical sensor according to <1>, wherein the emission wavelengths of the two or more light-emitting elements are different from each other. <3> The base material has a light-shielding frame that partitions the light-emitting element and the light-receiving element together with the light-shielding wall, The inner shape of the section consisting of the light-shielding wall and the light-shielding frame is a chamfered rectangular column. <1> or <2> The reflective optical sensor according to the present invention is <4> The thickness of the light-shielding frame is smaller than the thickness of the light-shielding wall. <3> The reflective optical sensor according to the present invention is <5> The substrate is a glass epoxy substrate having a light transmittance of 1% or less through the thickness of the substrate, the light-shielding wall is a glass epoxy substrate having a light transmittance of 1% or less through the thickness of the light-shielding wall, The light-shielding wall is provided on the base material via a light-shielding adhesive. <1> from <4> The reflective optical sensor according to any one of claims 1 to 5, Effect of the Invention

[0008] According to the present invention, it is possible to solve the above-mentioned problems in the conventional art, achieve the above-mentioned object, and provide a reflective optical sensor having a simple structure in which noise due to light from the surface of the object to be measured is reduced. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a reflective optical sensor according to the present embodiment. [Diagram 2] FIG. 2 is a schematic top view showing an example of the reflective optical sensor of this embodiment. [Diagram 3] FIG. 3 is a schematic cross-sectional view showing the non-detection distance of the reflective optical sensor of this embodiment. [Figure 4] FIG. 4 is a schematic cross-sectional view showing the non-sensing distance of a reflective optical sensor of the prior art. [Diagram 5] FIG. 5 is a schematic top view showing another example of the reflective optical sensor of this embodiment. [Figure 6] FIG. 6 is a schematic top view showing another example of the reflective optical sensor of this embodiment. [Figure 7] FIG. 7 is a schematic top view showing another example of the reflective optical sensor of this embodiment. [Figure 8]FIG. 8 is a schematic diagram showing an example of a conventional reflective optical sensor. [Figure 9] FIG. 9 is a schematic diagram showing another example of a conventional reflective optical sensor.

DETAILED DESCRIPTION OF THE INVENTION

[0010] (Reflective optical sensor) The reflective optical sensor of the present invention is a reflective optical sensor having a base material, a light-emitting element and a light-receiving element provided on the base material, and a light-shielding wall provided between the light-emitting element and the light-receiving element, wherein the distance d between the light-emitting element and the light-shielding wall e and the distance d between the light-receiving element and the light-shielding wall r and the thickness t of the light-shielding wall satisfy the following formula: d e + d r < t, and the shortest distance between the region that does not belong to either the region where the light emitted from the light-emitting element does not reach the measurement target and the region where the reflected light of the light emitted from the measurement target or the scattered light from the measurement target is not input to the light-receiving element and the sensor surface where the reflective optical sensor contacts the measurement target is 0.2 mm or more and 0.3 mm or less.

[0011] Here, an example of the reflective optical sensor of the present embodiment will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of the reflective optical sensor of the present embodiment, and FIG. 2 is a schematic top view of FIG. 1. As shown in FIGS. 1 to 2, the reflective optical sensor 10 has a base material 11, a light-emitting element 12 and a light-receiving element 13 provided on the base material 11, and a light-shielding wall 14 provided between the light-emitting element 12 and the light-receiving element 13. In the present embodiment, an aspect having one light-emitting element 12 is shown, but as shown in FIG. 5 and the like described later, two or more light-emitting elements may be provided.

[0012] The reflective optical sensor 10 includes a conductive wire 22a and a conductive part 23a for externally supplying power to the electrode 12e of the light emitting element 12, and a conductive wire 22b and a conductive part 23b for outputting a photocurrent externally from the electrode 13e of the light receiving element 13. The light emitting element 12 and the light receiving element 13 are electrically connected to these conductive wires 22 and conductive parts 23 so that power can be supplied and the photocurrent can be output. While the light emitting element 12 and the light receiving element 13 are provided adjacent to the light shielding wall 14, the conductive parts 23a and 23b to which the respective conductive wires 22a and 22b are connected are arranged and connected distally with respect to the light shielding wall 14.

[0013] The reflective optical sensor 10 further has a light shielding frame 21 on the base material 11 for partitioning the light emitting element 12 and the light receiving element 13 together with the light shielding wall 14. The light shielding wall 14 and the light shielding frame 21 are provided on the base material 11 via a light shielding adhesive layer 24. Each of the compartments for housing the light emitting element 12 and the compartment for housing the light receiving element 13 is filled with a transparent resin 25. The transparent resin 25 is a transparent resin having permeability with respect to the irradiation light of the light emitting element 12 and the reflected light or scattered light from the measurement object, and is, for example, an epoxy resin. The transparent resin 25 seals the light emitting element 12 and the light receiving element 13, respectively, for protecting them from, for example, impact, moisture, etc. The surface (upper surface) of the transparent resin 25 is formed flat at the same height as the light shielding wall 14 and the light shielding frame 21, and forms a sensor surface with which the measurement object comes into contact. Note that the light emitting element 12 and the light receiving element 13 are provided on the base material 11 via an optional adhesive layer 26.

[0014] As shown in FIGS. 1 to 2, in the reflective optical sensor 10, the distance d between the light emitting element 12 and the light shielding wall 14 e and the distance d between the light receiving element 13 and the light shielding wall 14 r and when the thickness of the light shielding wall 14 is t, these relationships satisfy the following formula: d e + d r < t. In other words, the light emitting element 12 and the light receiving element 13 are adjacent via the light shielding wall 14 so as to satisfy d e + d r < t. The light emitting element 12 and the light receiving element 13 are arranged at positions close to the light shielding wall 14, and the distances d e and the distance dr It means that a light-shielding wall 14 having a relatively thick thickness t is provided between the light-emitting element 12 and the light-receiving element 13.

[0015] FIG. 3 is a schematic cross-sectional view showing the non-detection distance of the reflection type optical sensor of the present embodiment, and FIG. 4 is a schematic cross-sectional view showing the non-detection distance of the reflection type optical sensor of the prior art. As shown in FIG. 3, a region A1 where the light emitted from the light-emitting element 12 does not reach the measurement target, and a region A2 where the reflected light of the light emitted from the measurement target or the scattered light from the measurement target is not input to the light-receiving element 13 can be referred to as regions that the reflection type optical sensor does not detect (non-detection regions). The region (referred to as region A3) that does not belong to either of the non-detection regions A1 and A2, and the shortest distance (also referred to as the non-detection distance) d between the reflection type optical sensor 10 and the sensor surface in contact with the measurement target is 0.2 mm or more and 0.3 mm or less. Here, the shortest distance d between the region A3 and the sensor surface is the length (shortest distance) between the parts where the region A3 and the sensor surface are closest to each other. In FIG. 3, it is the distance d shown between the intersection of the boundary line of the region A1 that forms an angle θ2 with the side surface of the light-shielding wall 14 and the boundary line of the region A2 that forms an angle θ4 with the side surface of the light-shielding wall 14 and the sensor surface of the reflection type optical sensor.

[0016] As shown in FIG. 3, when the reflection type optical sensor 10 satisfies d e +d r <t, compared with the prior art reflection type optical sensor that does not satisfy d e +d r <t, the overlap of the non-detection regions represented by the regions A1 and A2 can be widened. Therefore, the non-detection distance d can be set in the range of 0.2 mm or more and 0.3 mm or less.

[0017] Here, for example, when the reflective optical sensor 10 is used to detect biological information in blood, such as blood oxygen saturation or blood glucose concentration, the sensor surface of the reflective optical sensor 10 comes into contact with a living body as a measurement target. The structure of the skin of a living body is divided into three layers, namely, the "epidermis", the "dermis", and the "subcutaneous tissue" from the surface. The epidermis, which has a thickness of about 0.2 mm, has few blood vessels. The dermis and the subcutaneous tissue have a combined thickness of about 2 mm, and have many blood vessels. If reflected light or scattered light from the skin surface such as the epidermis is detected, it will lead to noise. According to the reflective optical sensor of this embodiment, the non-detection distance d is set to 0.2 mm or more, so that the noise caused by the light from the measurement target surface is not detected, and the non-detection distance d is set to 0.3 mm or less, so that the signal from the target measurement site (blood in the blood vessels) can be efficiently detected.

[0018] In Fig. 3, n1 indicates the refractive index of the transparent resin 25, and n2 indicates the refractive index of the object to be measured. θ1 and θ2 are angles that determine the non-sensing area A1, and indicate the maximum incident angle θ1 on the light-emitting side and the maximum exit angle θ2 on the light-emitting side, and θ3 and θ4 are angles that determine the non-sensing area A2, and indicate the maximum incident angle θ4 on the light-receiving side and the maximum receiving angle θ3 on the light-receiving side. θ1 and θ3 are determined by the dimensions of the light-emitting element and the light-receiving element, the shapes of the light-emitting area and the light-receiving area, the height of the light-shielding wall, and the distance between each element and the light-shielding wall, and θ2 and θ4 are determined by θ1 or θ3 and n1 and n2. The non-sensing distance d is determined by θ2 and θ4 and the thickness t of the light-shielding wall.

[0019] The materials for the base material 11, the light-shielding wall 14, and the light-shielding frame 21 are not particularly limited and can be selected appropriately depending on the purpose, but it is preferable that at least one of the components is glass epoxy, and it is more preferable that all of the components are glass epoxy. By using glass epoxy, it is possible to perform machining in the manufacture of reflective optical sensors. Since there is no need to use a mold for resin molding, this is advantageous in terms of manufacturing and processing, and cost, especially in small-scale production.

[0020] The base material 11 is preferably a glass epoxy substrate having a light transmittance of 1% or less through the thickness of the base material 11. The light-shielding wall 14 is preferably a glass epoxy substrate having a light transmittance of 1% or less through the thickness of the light-shielding wall 14. In particular, if the light transmittance through the thickness of the light-shielding wall 14 is 1% or less, the transmission of light from the light-emitting element 12 to the light-receiving element 13 through the light-shielding wall 14 can be prevented, and detection noise can be reduced. Here, the term "light transmittance through the thickness of a substrate" refers to the light transmittance in the thickness direction of a substrate having a specific thickness. The term "light transmittance in the thickness direction of the light-shielding wall" means the light transmittance in the thickness direction of the light-shielding wall having a specific thickness, the thickness of the light-shielding wall being perpendicular to the thickness direction of the base material. The light-shielding frame is similarly defined as a light-shielding frame having a specific thickness.

[0021] A glass epoxy board has different optical properties in the thickness direction (lamination direction) and in-plane direction, and a typical glass epoxy board may have low light blocking properties in the in-plane direction. An example of a glass epoxy substrate having high light-shielding properties and low light transmittance in the thickness direction and in-plane direction is a light-shielding black printed wiring board material CS-3667B (manufactured by Risho Kogyo Co., Ltd.). The light transmittance can be appropriately selected so long as it is 1% or less at the wavelengths of emitted and received light to be measured, but it is preferable that the light transmittance be 1% or less at wavelengths of 650 nm to 1,310 nm, and more preferably that the light transmittance be 1% or less at wavelengths of 250 nm to 2,000 nm.

[0022] The light-shielding wall 14 and the light-shielding frame 21 are preferably provided via an adhesive layer 24 formed on the base material 11 using a light-shielding adhesive. The light-shielding adhesive is not particularly limited and may be appropriately selected depending on the purpose. For example, an adhesive sheet AD-7006B (manufactured by Risho Kogyo Co., Ltd., average thickness: 0.05 mm) may be used.

[0023] As shown in FIG. 2, the reflection type optical sensor may be configured to have one light emitting element. As another embodiment, as shown in FIG. 5, it may be configured to have two or more light emitting elements provided adjacent to each other. Any of these embodiments can be preferably implemented. For example, in applications such as a pulse oximeter where multiple light emitting elements are used for detection depending on the object to be detected, there is an increasing trend. In order to reduce the size, a package of the same reflection type optical sensor with multiple light emitting elements and light receiving elements mounted thereon is known.

[0024] As shown in FIG. 5, when the reflection type optical sensor has two or more light emitting elements 12a and 12b, each light emitting element is e +d r adjacent to each other so as to satisfy the regulations of <t and the non-sensing distance d respectively. In other words, each of the light emitting elements 12a and 12b is arranged at a position close to the light shielding wall 14, and the light emitting elements 12a and 12b are arranged side by side with respect to the light shielding wall 14, and no other members are arranged therebetween. By satisfying the above configuration, for each light emitting element, the location dependence of the light irradiation characteristics and the light receiving characteristics can be reduced, and between two or more light emitting elements, the uniformity of the location-dependent characteristics of the light irradiation and the light receiving with respect to the measurement object can be enhanced.

[0025] When there are two or more light emitting elements, for example, in the photo reflector described in the conventional Patent Document 1, two light emitting elements (12) are provided in different compartments and are installed on both sides of the photodiode. Therefore, the irradiation conditions of the light irradiation from one light emitting element and the irradiation conditions of the light irradiation from the other light emitting element are significantly different. Therefore, there is a problem that the location-dependent characteristics of the light irradiation characteristics and the light receiving characteristics with respect to the measurement object are different between the two light emitting elements. In other words, due to the difference in the location where two or more light emitting elements are arranged on the base material, the optical characteristics of each light emitting element with respect to the light receiving element are different, or as a result, different parts of the measurement object (for example, parts with different blood densities) are sensed, resulting in a problem that the measurement uniformity between the light emitting elements is poor.

[0026] Also, Japanese Patent Application Laid-Open No. 2009-038322 has reported a reflective photosensor having two light-emitting elements in the same section. As shown in Fig. 9, in the reflective photosensor, the light-emitting and light-receiving surfaces of the light-emitting units (18a, 18b) and the light-receiving unit (20) are arranged in a direction perpendicular to the moving direction (H) of the object to be detected, which moves parallel to the light-emitting and light-receiving surfaces. The light-receiving unit (20) receives reflected light from the object to be detected, which is based on the output light of the light-emitting units (18a, 18b). The light-emitting units (18a, 18b) are provided with light-emitting regions in which the amount of light emitted is higher at both ends than at the center in the moving direction (H) of the object to be detected, so that the detection output of the light-receiving unit (20) changes linearly according to the amount of movement of the object to be detected.

[0027] In the reflective photosensor, although one section has two light-emitting elements, the bonding pattern (17c) is sandwiched between the two light-emitting elements, and the two light-emitting elements are spaced apart from each other. Therefore, as with the photoreflector described in Patent Document 1, the direction of light irradiation from one light-emitting element and the direction of light reception to the light-receiving element are different from the direction of light irradiation from the other light-emitting element and the direction of light reception to the light-receiving element, and there is a problem that the locations of the light irradiation characteristics and light reception characteristics for the measurement object are different between the multiple light-emitting elements. On the other hand, according to the reflective optical sensor of this embodiment having two or more adjacent light-emitting elements, the conventional problems can be solved, and the uniformity of the location of the light irradiation characteristics and light receiving characteristics for the measurement object can be increased between the two or more light-emitting elements.

[0028] It is preferable that the emission wavelengths of the two or more light-emitting elements are different from each other, which makes it possible to detect reflected light of two or more wavelengths, for example, two or more wavelengths that are significantly different from each other, and thus to detect a plurality of pieces of information, detect information based on the difference between the reflected lights of different wavelengths, and correct the information.

[0029] The wavelength can be appropriately selected depending on the information to be measured. Specifically, a pulse oximeter that measures blood oxygen saturation can detect the concentration of oxygenated hemoglobin (HbO2) by alternately irradiating red light (e.g., wavelength 660 nm) and infrared light (e.g., 940 nm) in pulses and measuring the difference between the reflected light. Also, a blood glucose meter can measure blood glucose concentration by correcting the reflected light of the glucose absorption wavelength (peak absorption wavelength 1,600 nm) with the reflected light of the water absorption wavelength (1,450 nm).

[0030] As another embodiment, as shown in FIG. 6, a light-shielding frame 21 that, together with a light-shielding wall 14, partitions the light-emitting element 12 and the light-receiving element 13, is provided on the substrate 11, and the inner shape of the partition formed by the light-shielding wall 14 and the light-shielding frame 21 is a chamfered rectangular column, which can also be preferably implemented. When the inner shape of the section is a chamfered rectangular column, the aperture can be made small, which reduces stray light components of emitted and received light, thereby reducing noise. Furthermore, when a base material such as a glass epoxy substrate is used for the light-shielding wall 14 and the light-shielding frame 21, cutting work can be easily performed, which is preferable in terms of processing and cost.

[0031] As shown in FIG. 7, an embodiment in which the thickness t1 of the light-shielding frame 21 is smaller than the thickness t of the light-shielding wall 14 can also be preferably implemented. The above embodiment can be easily manufactured by cutting with a thick dicing blade during element separation, etc. The thickness t1 of the light-shielding frame 21 can be made thin, and the package size of the reflective photosensor 10 can be made small. EXAMPLES

[0032] Example 1 As an example of the reflective optical sensor having two light-emitting elements shown in FIG. 5, a pulse oximeter for measuring blood oxygen saturation was fabricated. Specifically, as the two light-emitting elements that emit red light (wavelength 660 nm) and infrared light (940 nm), a red LED chip (PR7A, manufactured by DOWA Holdings Co., Ltd.) and an infrared LED chip (FP6E, manufactured by DOWA Holdings Co., Ltd.) were used. As the light-receiving element, a PD chip with a reduced size and light-receiving area of a large-area photodiode (KPD31S, manufactured by Kyoto Semiconductor Co., Ltd.) with a detection wavelength of 400 nm to 1,100 nm was used. Further, as the light-shielding wall and light-shielding frame, a glass epoxy substrate (black printed wiring board material, CS-3667B, manufactured by Risho Kogyo Co., Ltd.) with a light transmittance of 1% or less was used, and a light-shielding adhesive sheet (AD-7006B, manufactured by Risho Kogyo Co., Ltd.) was used as the light-shielding adhesive to fabricate the pulse oximeter of Example 1.

[0033] The light-emitting element had a size of 0.24 mm × 0.24 mm to 0.28 mm × 0.28 mm and a thickness of 0.15 mm. The light-receiving element had a size of 2.0 mm × 0.7 mm, a thickness of 0.3 mm, and a light-receiving area of 1.8 mm × 0.5 mm. The light-shielding wall had a thickness t = 0.8 mm and a height of 0.8 mm. The distance d between the light-shielding wall and each element e = d r = 0.2 mm, and d e + d r < t was satisfied. When calculated with a refractive index of 1.5 for the transparent resin and a refractive index of 1.4 for the human body as the measurement object, the non-perception distance d was approximately 0.24 mm.

[0034] In the pulse oximeter of Example 1, the two light-emitting elements were alternately pulse-irradiated, and the concentration of oxygenated hemoglobin (HbO2) could be detected from the difference between the reflected lights.

[0035] (Example 2) As an example of a reflection-type optical sensor having two light-emitting elements shown in FIG. 5, a blood glucose meter for measuring blood glucose concentration was fabricated. Specifically, an infrared LED chip used in an infrared LED (KEDE1652H, manufactured by Kyoto Semiconductor Co., Ltd., peak emission wavelength 1,650 nm) that emits light at the absorption wavelength of glucose (peak absorption wavelength 1,600 nm), and an infrared LED chip used in an infrared LED (KEDE1452H, manufactured by Kyoto Semiconductor Co., Ltd., peak emission wavelength 1,450 nm) as another light-emitting element that emits light at the absorption wavelength of water (1,450 nm) were used. A chip used in a photodiode (KPDE300 InGaAs photodiode, manufactured by Kyoto Semiconductor Co., Ltd.) that can detect 80% or more of wavelengths from 1,200 nm to 1,700 nm was used as the light-receiving element. Further, a glass epoxy substrate (black printed wiring board material, CS-3667B, manufactured by Lichang Industry Co., Ltd.) with a light transmittance of 1% or less was used as the light-shielding wall and light-shielding frame, and a light-shielding adhesive sheet (AD-7006B, manufactured by Lichang Industry Co., Ltd.) was used as the light-shielding adhesive to fabricate the blood glucose meter of Example 2.

[0036] The light-emitting element had a size of 0.35 mm × 0.35 mm and a thickness of 0.33 mm. The light-receiving element had a size of 0.44 mm × 0.44 mm, a thickness of 0.15 mm, and a light-receiving area diameter of 0.3 mm. The light-shielding wall had a thickness t = 0.8 mm and a height of 0.8 mm. The distance d between the light-shielding wall and each element e =d r = 0.3 mm, and d e +d r < satisfied t. When calculated with a refractive index of 1.5 for the transparent resin and a refractive index of 1.4 for the human body as the measurement object, the non-perception distance d was approximately 0.27 mm.

[0037] In the blood glucose meter of Example 2, by correcting the reflected light at the absorption wavelength of glucose (peak absorption wavelength 1,600 nm) with the reflected light at the absorption wavelength of water (1,450 nm), glucose can be detected with high precision without being affected by moisture, and thus, the blood glucose concentration can be measured.

[0038] The reflective optical sensors of Examples 1 and 2 all have a simple structure and do not require the use of a mold for resin molding in the manufacturing process. The angle between the emission angle of light emitted from the light-emitting element and the incidence angle of light received by the light-receiving element can be made small, and therefore the location dependency of the light emission characteristics and light receiving characteristics can be made small. In addition, since the non-detection distance d is set in the range of 0.2 mm to 0.3 mm, noise due to light from the surface of the living body as the measurement target is reduced, and at the same time, a signal due to light from blood in the living body can be strongly detected. [Explanation of symbols]

[0039] 10 Reflective optical sensor 11 Base material 12 Light emitting element 13 Photodetector 14 Blackout Wall 21 Light-shielding frame 22a, b Conductive wire 23a,b Conductive part 24 Adhesive layer 25 Transparent Resin A1 area 1 A2 area 2

Claims

1. A substrate; A light emitting element and a light receiving element provided on the substrate; a light-shielding wall provided between the light-emitting element and the light-receiving element, The distance d between the light emitting element and the light shielding wall ｅ and the distance d between the light receiving element and the light shielding wall ｒ The relationship between the thickness t of the light-shielding wall and the thickness t of the light-shielding wall is expressed by the following formula: ｅ +d ｒ <t, A reflective optical sensor characterized in that the shortest distance between an area that does not belong to either an area where the light emitted from the light-emitting element does not reach the object to be measured or an area where the reflected light of the light emitted from the object to be measured or the scattered light from the object to be measured is not input to the light-receiving element and the reflective optical sensor and a sensor surface with which the object to be measured comes into contact is 0.2 mm or more and 0.3 mm or less.

2. The light emitting element is two or more light emitting elements provided adjacent to each other, The reflective optical sensor according to claim 1 , wherein the two or more light-emitting elements have emission wavelengths different from each other.

3. a light-shielding frame that, together with the light-shielding wall, partitions the light-emitting element and the light-receiving element on the base material; 3. The reflective optical sensor according to claim 1, wherein an inner shape of a section defined by said light-shielding wall and said light-shielding frame is a chamfered quadrangular column.

4. 4. The reflective optical sensor according to claim 3, wherein the thickness of the light-shielding frame is smaller than the thickness of the light-shielding wall.

5. the substrate is a glass epoxy substrate having a light transmittance of 1% or less through the thickness of the substrate, the light-shielding wall is a glass epoxy substrate having a light transmittance of 1% or less through the thickness of the light-shielding wall, 3. The reflective optical sensor according to claim 1, wherein the light-shielding wall is provided on the base material via a light-shielding adhesive.

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