DETECTING DEVICE AND MEASURING DEVICE

A detecting device of the present disclosure includes a light emitting portion that emits light and a light receiving portion including an angle limiting member that limits an angle of incidence of light from the light emitting portion, wherein the light receiving portion has a first light receiving region and a second light receiving region that is spaced further from the light emitting portion than the first light receiving region is, the angle limiting member includes a first limiting region corresponding to the first light receiving region and a second limiting region corresponding to the second light receiving region, and the degree of angle limitation of the second limiting region is smaller than the degree of angle limitation of the first limiting region.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based on, and claims priority from JP Application Serial Number 2021-177280, filed Oct. 29, 2021, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a detecting device and a measuring device.

2. Related Art

Various measurement technologies for non-invasively measuring biological information such as heartbeats have been proposed in the related art. For example, JP-A-2012-194054 discloses a technology in which, in a detecting device including a light emitting portion that emits light to a living body and a light receiving portion that receives light that is incident thereon by being reflected by the living body after being emitted from the light emitting portion, a spectroscopic filter and an angle limiting filter are provided in the light receiving portion such that stray light transmitted through the spectroscopic filter is blocked by the angle limiting filter.

However, in the above detecting device, the amount of received light varies over the surface of the light receiving portion and thus it has been desired to provide a new technology capable of allowing light to be efficiently incident on the light receiving portion to further improve the detection accuracy.

SUMMARY

An aspect of the present disclosure provides a detecting device including a light emitting unit that emits a light, and a light receiving unit that includes: a sensor having a first light receiving region and a second light receiving region away from the light emitting unit than the first light receiving region, and an angle limiting having a first limiting region corresponding to the first light receiving region and a second limiting region corresponding to the second light receiving region, wherein a degree of angle limitation of the second limiting region is smaller than a degree of angle limitation of the first limiting region.

An aspect of the present disclosure provides a detecting device including a light emitting unit configured to emit light to a living body, a light receiving unit arranged in a first direction with respect to the light emitting unit and configured to receive light from the living body, and a plurality of light shielding walls arranged in the first direction and configured to limit an angle of incidence of light on the light receiving unit, wherein an interval between the light shielding walls in a region far from the light emitting unit is larger than an interval between the light shielding walls in a region close to the light emitting unit.

An aspect of the present disclosure provides a measuring device including the detecting device according to the above aspect and an information analysis unit configured to identify biological information from a detection signal indicating a detection result of the detecting device.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each of the following drawings, the scales and angles of members are made different from those of actual ones in order to make the members recognizable in size.

First Embodiment

FIG.1is a side view of a measuring device100of a first embodiment. The measuring device100of the present embodiment illustrated inFIG.1is a biometric device that non-invasively measures biometric information of a subject (for example, a human) which is an example of a living body and is attached to a site (hereinafter referred to as a “measuring site”) M that is a measurement target on a body of the subject. The measuring device100of the present embodiment is a wristwatch-type portable device including a main body1and a belt2and can be worn on a wrist of the subject, which is an example of the measuring site (the living body) M, by winding the belt2in a band shape around the wrist. In the present embodiment, biological information is exemplified by a heartbeat (for example, a pulse rate) and an oxygen saturation (SpO2) of the subject. The heartbeat indicates the change of the internal volume of a blood vessel over time due to the pulsation of the heart. The oxygen saturation indicates the proportion (%) of hemoglobin bound to oxygen in hemoglobin in the blood of the subject and is an index for evaluating the respiratory function of the subject.

FIG.2is a configuration diagram focusing on the functionality of the measuring device100. As illustrated inFIG.2, the measuring device100of the present embodiment includes a control device5, a storage device6, a display device4, and a detecting device3. The control device5and the storage device6are installed inside the main body1. As illustrated inFIG.1, the display device4is installed on a surface of the main body1opposite to the measuring site M and displays various images including measurement results under the control of the control device5. The display device4is, for example, a liquid crystal display panel.

The detecting device3is an optical sensor module that generates detection signals S according to the state of the measuring site M. As illustrated inFIG.1, the detecting device3is installed, for example, on a surface (hereinafter referred to as a detection surface)16of the main body1that faces the measuring site M. The detection surface16is a surface that comes into contact with the measuring site M. As illustrated inFIG.2, the detecting device3of the present embodiment includes a light emitting unit (a light emitting portion)11, a light receiving unit (a light receiving portion)12, a drive circuit13, and an output circuit14. One or both of the drive circuit13and the output circuit14can also be installed as circuits external to the detecting device3. That is, the drive circuit13and the output circuit14may be omitted from the detecting device3.

The light emitting unit11includes a first light emitting element50, a second light emitting element60, and a third light emitting element70. The first light emitting element50, the second light emitting element60, and the third light emitting element70are elements that emit light having different wavelengths to the measuring site M.

The first light emitting element50emits green light (first light) LG having a green wavelength band of 500 nm to 550 nm toward the measuring site M. The green light LG of the present embodiment is, for example, light having a peak wavelength of 520 nm.

The second light emitting element60emits red light (second light) LR having, for example, a red wavelength band of 600 nm to 800 nm toward the measuring site M. The red light LR of the present embodiment is, for example, light having a peak wavelength of 660 nm.

The third light emitting element70emits near-infrared light (third light) LI having, for example, a near-infrared wavelength band of 800 nm to 1300 nm toward the measuring site M. The near-infrared light LI of the present embodiment is, for example, light having a peak wavelength of 905 nm.

For example, light emitting diodes (LED) of a bare chip or bullet type are preferably used as light emitting elements that constitute the first light emitting element50, the second light emitting element60, and the third light emitting element70. The wavelengths of light emitted by the light emitting elements are not limited to the above numerical ranges. Hereinafter, the first light emitting element50, the second light emitting element60, and the third light emitting element70are collectively referred to as “each of the light emitting elements50,60, and70” unless particularly specified.

The drive circuit13supplies a drive current to cause each of the light emitting elements50,60, and70to emit light. The drive circuit13of the present embodiment periodically causes each of the light emitting elements50,60, and70to emit light in a time division manner. Light emitted from the light emitting elements50,60, and70is incident on the measuring site M and propagates in the measuring site M while being repeatedly reflected and scattered and then is emitted to the main body1side, reaching the light receiving unit12. That is, the detecting device3of the present embodiment is a reflection type optical sensor in which the light emitting unit11and the light receiving unit12are located on one side of the measuring site M.

The light receiving unit12receives light arriving from the measuring site M after being emitted by the light emitting unit11. The light receiving unit12of the present embodiment includes a first light receiving element51and a second light receiving element61. The first light receiving element51and the second light receiving element61generate detection signals according to the intensity of received light. Hereinafter, the first light receiving element51and the second light receiving element61are collectively referred to as “each of the light receiving elements51and61” unless particularly specified.

The first light receiving element51receives green light LG that has propagated in the measuring site M after being emitted from the first light emitting element50and generates a detection signal according to the intensity of received light. The second light receiving element61receives red light LR that has propagated in the measuring site M after being emitted from the second light emitting element60or near-infrared light LI that has propagated in the measuring site M after being emitted from the third light emitting element70and generates detection signals according to the intensity of received light.

The output circuit14is configured to include, for example, an A/D converter that converts detection signals generated by the light receiving elements51and61from analog to digital and an amplifier circuit that amplifies the converted detection signals (both not illustrated) and generates a plurality of detection signals S (S1, S2, S3) corresponding to different wavelengths.

The detection signal S1is a signal indicating the intensity of light received by the first light receiving element51when it has received green light LG emitted from the first light emitting element50. The detection signal S2is a signal indicating the intensity of light received by the second light receiving element61when it has received red light LR emitted from the second light emitting element60. The detection signal S3is a signal indicating the intensity of light received by the second light receiving element61when it has received near-infrared light LI emitted from the third light emitting element70.

Each detection signal S is a heartbeat signal including periodic fluctuations corresponding to pulsations (volume heartbeats) of the artery inside the measuring site M because the amounts of absorption by blood during dilation and contraction of blood vessels generally differ.

The drive circuit13and the output circuit14are mounted on a wiring board in the form of an IC chip together with the light emitting unit11and the light receiving unit12. The drive circuit13and the output circuit14can be installed outside the detecting device3as described above.

The control device5is an arithmetic processing unit such as a central processing unit (CPU) or a field-programmable gate array (FPGA) and controls the entirety of the measuring device100. The storage device6includes, for example, a non-volatile semiconductor memory and stores a program executed by the control device5and various data used by the control device5. It is also possible to adopt a configuration in which the functions of the control device5are distributed over a plurality of integrated circuits or a configuration in which some or all of the functions of the control device5are realized by a dedicated electronic circuit. Although the control device5and the storage device6are illustrated as separate elements inFIG.2, a control device5including the storage device6can also be realized, for example, by an application specific integrated circuit (ASIC).

The control device5of the present embodiment identifies biological information of the subject from the plurality of detection signals S (S1, S2, S3) generated by the detecting device3by executing the program stored in the storage device6. Specifically, the control device5can identify a pulse-to-pulse interval (PPI) of the subject from the detection signal S1indicating the intensity of green light LG received by the first light receiving element51. The control device5can also identify the oxygen saturation (SpO2) of the subject by analyzing the detection signal S2indicating the intensity of red light LR received by the second light receiving element61and the detection signal S3indicating the intensity of near-infrared light LI received by the second light receiving element61.

In the measuring device100of the present embodiment, the control device5functions as an information analysis unit that identifies biological information from the detection signals S indicating the detection results of the detecting device3as described above. The control device (information analysis unit)5causes the display device4to display the biological information identified from the detection signals S. It is also possible to notify the user of the measurement result by voice output. It is also preferable to adopt a configuration in which the user is notified of a warning (possibility of impaired physical function) when the pulse rate or oxygen saturation has fluctuated to values out of a predetermined range.

FIG.3is a plan view of the detecting device3of the present embodiment.FIG.4is a cross-sectional view taken along a line IV-IV inFIG.3. As illustrated inFIGS.3and4, the detecting device3of the present embodiment includes a case40and a sealing layer42in addition to the light emitting unit11and the light receiving unit12. The drive circuit13and the output circuit14are not illustrated inFIGS.3and4.

Hereinafter, the configuration of the detecting device3will be described using an XYZ coordinate system. The X-axis corresponds to an axis extending along a long side (one side) of the case40having a rectangular outer shape, the Y-axis corresponds to an axis that is orthogonal to the X-axis and extends along a short side (another side) of the case40, and the Z-axis corresponds to an axis that is orthogonal to the X and Y-axes and extends across the thickness of the case40.

As illustrated inFIGS.3and4, the case40is a member that holds the elements of the detecting device3(the light emitting unit11and the light receiving unit12). The case40is in the shape of a box including a bottom surface portion40ain the shape of a rectangular flat plate, a frame plate portion40bin the shape of a rectangular frame that projects to the +Z side from peripheral edges of the bottom surface portion40a, and a partition wall41. The case40is made of, for example, aluminum. An inner peripheral surface40b1of the frame plate portion40bis colored black to have light blocking properties. This limits reflection on the inner peripheral surface40b1of the frame plate portion40b.

The material and manufacturing method of the case40are arbitrary. For example, the case40can be formed by injection molding of a resin material. It is also preferable to adopt a configuration in which the case40is integrally formed with the main body1.

The light emitting unit11and the light receiving unit12are installed on the bottom surface portion40aof the case40while being mounted on a wiring board (not illustrated). In the case40, the light emitting unit11and the light receiving unit12are arranged in the X-axis direction (a first direction).

The partition wall41is a plate-shaped member that protrudes to the +Z side from the bottom surface portion40aand extends in the Y-axis direction and separates the internal accommodation space of the case40into two parts in the X-axis direction. That is, the partition wall41is a member that separates the space accommodating the light emitting unit11and the light receiving unit12in a direction along the X axis. The partition wall41is a member having light blocking properties for blocking light emitted from the light emitting unit11such that it is not directly incident on the light receiving unit12. It can also be said that the partition wall41is a member that blocks a part of the green light LG, the red light LR, and the near-infrared light LI.

The sealing layer42is a light-transmitting resin material filled in a gap between the frame plate portion40band the light emitting and receiving units11and12accommodated in the case40. In the present embodiment, the sealing layer42seals the light emitting elements50,60, and70and the light receiving elements51and61. The sealing layer42seals (molds) the light emitting and receiving units11and12in the case40. In the present embodiment, an upper surface of the sealing layer42is flush with upper surfaces of the frame plate portions40band41of the case40. The surface of the sealing layer42functions as the detection surface16.

The light emitting unit11is installed in the case40such that the light emitting surfaces of the light emitting elements50,60, and70are parallel to the XY plane. That is, the light emitting elements50,60, and70emit light toward the +Z side.

The light receiving unit12is installed in the case40such that the light receiving surfaces of the light receiving elements51and61are parallel to the XY plane. That is, the light receiving elements51and61receive light incident from the Z direction.

As illustrated inFIG.3, the light emitting elements50,60, and70are arranged side by side at intervals in the Y-axis direction (a second direction) orthogonal to (intersecting) the X-axis direction. Specifically, the second light emitting element60is arranged on the +Y side of the first light emitting element50and the third light emitting element70is arranged on the −Y side of the first light emitting element50. That is, the first light emitting element50is arranged between the second light emitting element60and the third light emitting element70in the direction along the Y axis. It can also be said that the first light emitting element50is located between the second light emitting element60and the third light emitting element70.

The light receiving elements51and61are arranged side by side at intervals in the X-axis direction intersecting (orthogonal to) the Y axis. Specifically, the first light receiving element51is arranged on the +X side of the light emitting unit11and the second light receiving element61is arranged on the +X side of the first light receiving element51. That is, the second light receiving element61is arranged on a side of the first light receiving element51opposite to the light emitting unit11.

Here, let D1be a distance from the first light emitting element50to the first light receiving element51, D2a distance from the second light emitting element60to the second light receiving element61, and D3a distance from the third light emitting element70to the second light receiving element61. The distance D1corresponds to the distance between central portions of the first light emitting element50and the first light receiving element51when viewed in plan in the Z-axis direction. The distance D2corresponds to the distance between central portions of the second light emitting element60and the second light receiving element61when viewed in plan in the Z-axis direction. The distance D3corresponds to the distance between central portions of the third light emitting element70and the second light receiving element61when viewed in plan in the Z-axis direction.

In the detecting device3of the present embodiment, the distance D1from the first light emitting element50to the first light receiving element51is shorter than the distance D2from the second light emitting element60to the second light receiving element61. The distance D1from the first light emitting element50to the first light receiving element51is also shorter than the distance D3from the third light emitting element70to the second light receiving element61. The distance D2and the distance D3are equal.

As described above, the detecting device3of the present embodiment adopts a configuration in which the first light receiving element51for receiving green light LG is arranged at a position closest to the first light emitting element50that emits the green light LG. That is, the first light receiving element51is provided closer to the light emitting unit11than the second light receiving element61is in the X-axis direction in which the light emitting unit11and the light receiving unit12are arranged.

As illustrated inFIG.4, the first light receiving element51includes a sensor20, a first angle limiting filter (angle limiting member)21, and a bandpass filter22.

The sensor20includes, for example, a photodiode (PD). The first angle limiting filter21is provided to cover the entirety of a light receiving surface20aof the sensor20.

The first angle limiting filter21has a property of transmitting light incident at an angle smaller than a predetermined incident angle and blocking light incident at an angle larger than the predetermined incident angle without transmitting the light. Thus, the first angle limiting filter21can limit the angle of incidence of light on the sensor20.

Specifically, the first angle limiting filter21transmits light which is incident at a predetermined incident angle (hereinafter referred to as an allowable incident angle) due to having propagated in the living body and guides it to the sensor20and blocks light which is incident at an angle larger than the allowable incident angle, such as external light such as sunlight or light which has not entered the living body, to prevent it from being incident on the sensor20. That is, the first angle limiting filter21is an angle limiting member that limits the angle of incidence of green light LG from the first light emitting element50with respect to the sensor20. Details of the configuration of the first angle limiting filter21will be described later.

The bandpass filter22has a property of selectively transmitting the wavelength band of green light LG and absorbing and blocking red light LR and near-infrared light LI which are light of other wavelength bands. The bandpass filter22is formed, for example, by alternately laminating low refractive index layers such as silicon oxide layers and high refractive index layers such as titanium oxide layers on the first angle limiting filter21.

For example, a part of red light LR and near-infrared light LI emitted from the second and third light emitting elements60and70may pass through the living body and enter the first light receiving element51. In the case of the present embodiment, the first light receiving element51includes the bandpass filter22that selectively transmits green light LG. Therefore, the first light receiving element51can block red light LR and near-infrared light LI having wavelength bands different from that of green light LG. Thus, the first light receiving element51can efficiently receive green light LG emitted from the first light emitting element50.

The second light receiving element61includes a sensor30that receives red light LR or near-infrared light LI and a second angle limiting filter (angle limiting member)31that limits the angle of incidence of red light LR or near-infrared light LI that reaches the sensor30. That is, in the detecting device3of the present embodiment, the second light receiving element61differs from the first light receiving element51in that it does not include a bandpass filter that selectively transmits red light LR or near-infrared light LI.

The sensor30includes, for example, a photodiode. The second angle limiting filter31is provided to cover the entirety of a light receiving surface30aof the sensor30. The second angle limiting filter31can limit the angle of incidence of red light LR or near-infrared light LI that reaches the sensor30.

For example, the second angle limiting filter31transmits red light LR or near-infrared light LI which is incident at an allowable incident angle after propagating in the living body and guides it to the sensor30and blocks light which is incident at an angle larger than the allowable incident angle, such as external light such as sunlight or red light LR or near-infrared light LI which has not passed through the living body, to prevent it from being incident on the sensor30. That is, the second angle limiting filter31is an angle limiting member that limits the angle of incidence, with respect to the sensor30, of red light LR or near-infrared light LI from the second light emitting element60or the third light emitting element70. Details of the configuration of the second angle limiting filter31will be described later.

FIG.5is a diagram illustrating the behavior of light emitted from the light emitting unit11.

As illustrated inFIG.5, for example, a part of green light LG emitted from the first light emitting element50may be reflected by a surface layer of the living body (the measuring site M), such that it is directly incident on the first light receiving element51without reaching the blood vessel M1inside the living body. External light such as sunlight may also be directly incident on the first light receiving element51through a gap between the living body and the detection surface16.

Green light LG that is directed to the first light receiving element51without reaching the blood vessel M1is referred to as a “first stray light component SL1” and external light that is directed directly to the first light receiving element51is referred to as a “second stray light component SL2”.

Because the first stray light component SL1has a green wavelength band, it passes through the bandpass filter22and is incident on the first angle limiting filter21provided in a layer below the bandpass filter22. The first angle limiting filter21has a property of transmitting light incident at an angle smaller than the allowable incident angle and blocking light incident at an angle larger than the allowable incident angle as described above.

Because the first stray light component SL1is incident on the first light receiving element51without reaching the blood vessel M1, the angle of incidence of the first stray light component SL1with respect to the first light receiving element51is larger than the allowable incident angle of the first angle limiting filter21. That is, the first stray light component SL1is blocked by the first angle limiting filter21. Thus, the first light receiving element51can limit the incidence of the first stray light component SL1on the light receiving surface20aof the sensor20through the first angle limiting filter21.

The second stray light component SL2is mostly blocked by the bandpass filter22, but a component having a green wavelength band included in the second stray light component SL2passes through the bandpass filter22. Here, the angle of incidence of the second stray light component SL2with respect to the first light receiving element51is larger than the allowable incident angle of the first angle limiting filter21because the second stray light component SL2is incident through the gap between the living body and the detection surface16as described above. Therefore, a part of the second stray light component SL2(a component having a green wavelength band) transmitted through the bandpass filter22is blocked by the first angle limiting filter21. Thus, the first light receiving element51can limit the incidence of the second stray light component SL2on the light receiving surface20aof the sensor20through the first angle limiting filter21.

On the other hand, green light LG that has propagated in the blood vessel M1passes through the bandpass filter22and is incident on the first angle limiting filter21provided in the layer below the bandpass filter22at a predetermined angle. Because the green light LG that has propagated in the blood vessel M1is emitted from the inside of the living body, it is incident on the first light receiving element51at a smaller incident angle, that is, at an angle closer to the normal direction, compared to the first stray light component SL1reflected on the surface layer of the living body.

The allowable incident angle of the angle limiting filter is generally designed to be smaller than the angle of incidence of light that has propagated in the blood vessel with respect to the light receiving unit. The angle limiting filter is formed, for example, by embedding light shielding walls made of a light blocking material such as tungsten in a light-transmitting silicon oxide layer using a semiconductor process. In the related art, a general angle limiting filter has been configured by embedding light shielding walls arranged at equal intervals in a silicon oxide layer.

Based on simulations, the present inventor has found that light that has passed through the living body cannot be efficiently incident on the light receiving surface of the sensor of the light receiving unit when an angle limiting filter of the related art in which light-shielding walls are embedded in a silicon oxide layer at equal intervals is used.

In a light receiving element using an angle limiting filter in which light shielding walls are embedded at equal intervals as in the configuration of the related art, a light incident region in which green light LG is mostly incident is formed on the light receiving surface near the first light emitting element50and the amount of received green light LG incident on the light receiving surface decreases away from the first light emitting element50. That is, the amount of light received by the light receiving element varies over the surface when the angle limiting filter of the related art in which light shielding walls are embedded at equal intervals is used.

FIG.6is a graph showing a transmission spectrum of the skin. InFIG.6, the horizontal axis represents the wavelength of light and the vertical axis represents the transmittance (in percentage).FIG.6shows a transmission spectrum when the skin thickness is 0.43 mm as an example.

As shown inFIG.6, the transmittance is about 30% when the wavelength band of green light LG (for example, 520 nm) is incident on the skin, about 50% to 60% when the wavelength band of red light LR (for example, 660 nm) is incident on the skin, and about 60% when the wavelength band of near-infrared light LI (for example, 905 nm) is incident on the skin.

The graph ofFIG.6shows that the distance that light can propagate in the living body differs depending on the wavelength of light. That is, according to the graph ofFIG.6, it can be seen that green light LG can propagate only a short distance in the living body, compared to red light LR or near-infrared light LI. That is, it can be said that red light LR and near-infrared light LI can propagate further in the living body than green light LG. AlthoughFIG.6illustrates the case where the skin thickness is 0.43 mm as an example, red light LR and near-infrared light LI can also propagate further in the living body with other skin thicknesses than green light LG.

The present inventor has found that green light LG is more likely to be attenuated when passing through a living body than red light LR and near-infrared light LI are as shown in the graph ofFIG.6. Thus, the present inventor has thought that, in a light receiving element using an angle limiting filter in which light shielding walls are embedded at equal intervals as in the related art, the likelihood that green light LG is attenuated in the living body before it is incident on the light receiving surface increases away from the first light emitting element50, and as a result, the amount of received light varies over the light receiving surface in the X-axis direction away from the first light emitting element50.

Therefore, the present inventor has focused on the structure of the angle limiting filter and completed the detecting device3of the present embodiment which can limit variations in the amount of received light over the light receiving element.

FIG.7is a cross-sectional view illustrating a configuration of a main part of the detecting device3of the present embodiment.

As illustrated inFIG.7, the first light receiving element51has a plurality of light receiving regions. The plurality of light receiving regions include a first light receiving region IA1, a second light receiving region IB1, a third light receiving region IC1, and a fourth light receiving region ID1. Hereinafter, the first light receiving region IA1, the second light receiving region IB1, the third light receiving region IC1, and the fourth light receiving region ID1are collectively referred to as “each of the light receiving regions IA1, IB1, IC1, and ID1” unless particularly specified.

The light receiving regions IA1, IB1, IC1, and ID1are provided on the light receiving surface20aof the sensor20of the first light receiving element51. Specifically, the first light receiving region IA1is a region which is located closest to the light emitting unit11(located on the most −X side) in the light receiving surface20aof the sensor20. The second light receiving region IB1is a region that is spaced further from the light emitting unit11to the +X side than the first light receiving region IA1is, the third light receiving region IC1is a region that is spaced further from the light emitting unit11to the +X side than the second light receiving region IB1is, and the fourth light receiving region ID1is a region that is spaced further from the light emitting unit11to the +X side than the third light receiving region IC1is. That is, the light receiving regions IA1, IB1, IC1and ID1are arranged on the light receiving surface20aone by one on the +X side in this order.

The first angle limiting filter21includes a first limiting region21A, a second limiting region21B, a third limiting region21C, and a fourth limiting region21D. Hereinafter, the first limiting region21A, the second limiting region21B, the third limiting region21C, and the fourth limiting region21D are collectively referred to as “each of the limiting regions21A,21B,21C, and21D” unless particularly specified.

The limiting regions21A,21B,21C, and21D correspond respectively to the light receiving regions IA1, IB1, IC1, and ID1.

The first limiting region21A is arranged to overlap the first light receiving region IA1when viewed in plan from the +Z side and limits the angle of incidence of the green light LG with respect to the first light receiving region IA1of the first light receiving element51.

The second limiting region21B is arranged to overlap the second light receiving region IB1when viewed in plan from the +Z side and limits the angle of incidence of the green light LG with respect to the second light receiving region IB1of the first light receiving element51.

The third limiting region21C is arranged to overlap the third light receiving region IC1when viewed in plan from the +Z side and limits the angle of incidence of the green light LG with respect to the third light receiving region IC1of the first light receiving element51.

The fourth limiting region21D is arranged to overlap the fourth light receiving region ID1when viewed in plan from the +Z side and limits the angle of incidence of the green light LG with respect to the fourth light receiving region ID1of the first light receiving element51.

In the present embodiment, the degree of angle limitation of the second limiting region21B is smaller than the degree of angle limitation of the first limiting region21A. The degree of angle limitation of the third limiting region21C is smaller than the degree of angle limitation of the second limiting region21B. The degree of angle limitation of the fourth limiting region21D is smaller than the degree of angle limitation of the third limiting region21C.

That is, in the detecting device3of the present embodiment, the degree of angle limitation of each of the limiting regions21A,21B,21C, and21D progressively decreases away from the first light emitting element50.

Here, the degree of angle limitation being “small” indicates that light incident on the first light receiving element51at a large incident angle (a shallow angle] away from the vertical direction) can reach the light receiving surface20aof the sensor20, i.e., that the allowable incident angle is large.

On the other hand, the degree of angle limitation being “large” indicates that light incident on the first light receiving element51at a small incident angle (a steep angle close to the vertical direction) can reach the light receiving surface20aof the sensor20, i.e., that the allowable incident angle is small.

The first angle limiting filter21includes a silicon oxide layer24and a plurality of light shielding walls (first light shielding walls)25embedded in the silicon oxide layer24. Each of the light shielding walls25is formed in a plate shape extending to the +Z side from the light receiving surface20aof the sensor20. Although omitted inFIG.7, the plurality of light shielding walls25are arranged not only in the X-axis direction but also in the Y-axis direction such that they form a grid shape as a whole when viewed in plan from the +Z side.

The first angle limiting filter21is formed, for example, by embedding light shielding walls25made of conductive plugs having light absorptivity such as tungsten plugs in a silicon oxide layer24through a wiring forming process of a semiconductor process. The silicon oxide layer24forms an optical path for guiding light to the light receiving surface20aof the sensor20. The light shielding walls25embedded in the silicon oxide layer24limit the angle of incidence of light passing through the optical path (the silicon oxide layer24). That is, when light incident on the silicon oxide layer24is tilted more than a predetermined angle with respect to the optical path, the incident light hits a light shielding wall25and a part of the light is absorbed by the light shielding wall25while the rest is reflected. Because the intensity of the reflected light is weakened due to repeated reflections while the light passes through the optical path, light that can completely pass through the first angle limiting filter21is substantially limited to light whose inclination with respect to the optical path is within a predetermined limiting angle.

Based on such a configuration, the first angle limiting filter21functions as an angle limiting member that limits the angle of incidence of green light LG from the first light emitting element50with respect to the sensor20.

In the first angle limiting filter21of the present embodiment, the plurality of light shielding walls25are provided on the light receiving regions IA1, IB1, IC1, and ID1of the first light receiving element51. The plurality of light shielding walls25include light shielding walls25a,25b,25c,25d, and25e.

The light shielding walls25aand25bdefine the first limiting region21A in the X-axis direction. The light shielding walls25band25cdefine the second limiting region21B in the X-axis direction. The light shielding walls25cand25ddefine the third limiting region21C in the X-axis direction. The light shielding walls25dand25edefine the fourth limiting region21D in the X-axis direction.

The degrees of angle limitation of the limiting regions21A,21B,21C, and21D are defined by the X-axis intervals between adjacent light shielding walls.

In the present embodiment, the plurality of light shielding walls that limit the angle of incidence of light on the light receiving unit12are arranged in the X-axis direction such that the interval between light shielding walls in a region far from the light emitting unit11is larger than the interval between light shielding walls in a region close to the light emitting unit11. Specifically, the X-axis interval between the adjacent light shielding walls25band25cin the second limiting region21B among the plurality of light shielding walls25is larger than the X-axis interval between the adjacent light shielding walls25aand25bin the first limiting region21A among the plurality of light shielding walls25.

The X-axis interval between the adjacent light shielding walls25cand25din the third limiting region21C among the plurality of light shielding walls25is larger than the X-axis interval between the adjacent light shielding walls25band25cin the second limiting region21B among the plurality of light shielding walls25.

The X-axis interval between the adjacent light shielding walls25dand25ein the fourth limiting region21D among the plurality of light shielding walls25is larger than the X-axis interval between the adjacent light shielding walls25cand25din the third limiting region21C among the plurality of light shielding walls25.

In the case of the present embodiment, for example, the interval between the light shielding walls25aand25bis set to 3 μm, the interval between the light shielding walls25band25cis set to 4.5 μm, the interval between the light shielding walls25cand25dis set to 6 μm, and the interval between the light shielding walls25dand25eis set to 7.5 μm. The heights of the light shielding walls25a,25b,25c,25d, and25eare set to 5 μm.

The allowable incident angle of the second limiting region21B is larger than the allowable incident angle of the first limiting region21A because the second limiting region21B has a larger interval in the X-axis direction than the first limiting region21A as illustrated inFIG.7.

In the first angle limiting filter21of the present embodiment, the X-axis intervals between adjacent light shielding walls are adjusted as described above such that the degree of angle limitation of the second limiting region21B is smaller than the degree of angle limitation of the first limiting region21A.

The allowable incident angle of the third limiting region21C is larger than the allowable incident angle of the second limiting region21B because the third limiting region21C has a larger interval in the X-axis direction than the second limiting region21B.

In the first angle limiting filter21of the present embodiment, the X-axis intervals between adjacent light shielding walls are adjusted as described above such that the degree of angle limitation of the third limiting region21C is smaller than the degree of angle limitation of the second limiting region21B.

The allowable incident angle of the fourth limiting region21D is larger than the allowable incident angle of the third limiting region21C because the fourth limiting region21D has a larger interval in the X-axis direction than the third limiting region21C.

In the first angle limiting filter21of the present embodiment, the X-axis intervals between adjacent light shielding walls are adjusted as described above such that the degree of angle limitation of the fourth limiting region21D is smaller than the degree of angle limitation of the third limiting region21C.

The first light receiving element51of the present embodiment is provided with the first angle limiting filter21such that the degree of angle limitation (the allowable incident angle) of the first light receiving element51decreases toward the +X side away from the first light emitting element50as described above.

Green light LG that has propagated in the blood vessel M1is emitted from the living body while being scattered as illustrated inFIG.5. Therefore, green light LG that has propagated in the blood vessel M1has scattering components. A part of the scattering components includes scattering components LG1directed to the +X side of specular reflection components from the living body.

The scattering components LG1have a larger angle of incidence with respect to the first light receiving element51than the specular reflection components of green light LG that are emitted after propagating in the blood vessel M1. That is, the scattering components LG1have a larger inclination with respect to the normal direction of the light receiving surface20aof the sensor20.

Therefore, in the case of an angle limiting filter in which light shielding walls are embedded at equal intervals, the degree of angle limitation is constant in the X-axis direction, such that the scattering components LG1having a larger angle of incidence than the specular reflection components of the green light LG are blocked by the light shielding walls and cannot be incident on the light receiving surface20aof the sensor20.

On the other hand, in the first angle limiting filter21of the present embodiment, the degree of angle limitation of the first light receiving element51(the light receiving surface20aof the sensor20) decreases toward the +X side. That is, the first light receiving element51has a larger allowable incident angle on the +X side than on the −X side, such that it can transmit even the scattering components LG1having a large inclination with respect to the normal direction of the light receiving surface20aof the sensor20.

The first angle limiting filter21can allow the scattering components LG1to be incident on the light receiving surface20aof the sensor20, for example, via the third limiting region21C or the fourth limiting region21D having a relatively large allowable incident angle.

According to the first light receiving element51of the present embodiment, the first angle limiting filter21whose degree of angle limitation decreases toward the +X side away from the first light emitting element50is provided, such that it is possible to inject the scattering components LG1, which are blocked by the angle limiting filter of the related art, into the sensor20. Thus, the first light receiving element51reduces variations in the amount of received light over the light receiving surface20aof the sensor20and efficiently injects green light LG emitted from the light emitting unit11into the sensor20, thus achieving high detection accuracy.

Here, in the detecting device3of the present embodiment, a part of the red light LR emitted from the second light emitting element60or a part of the near-infrared light LI emitted from the third light emitting element70may be directly incident on the second light receiving element61without passing through the living body as illustrated inFIG.5. External light such as sunlight may also be directly incident on the second light receiving element61through the gap between the living body and the detection surface16. Hereinafter, red light LR or near-infrared light LI that is directed directly to the second light receiving element61without passing through the living body is collectively referred to as a “third stray light component SL3” and external light that is directed directly to the second light receiving element61is referred to as a “fourth stray light component SL4”.

Because the third stray light component SL3is incident on the second angle limiting filter31without passing through the living body, the angle of incidence of the third stray light component SL3with respect to the second light receiving element61is larger than the allowable incident angle of the second angle limiting filter31. Because the fourth stray light component SL4is incident through the gap between the living body and the detection surface16, the angle of incidence of the fourth stray light component SL4with respect to the second light receiving element61is larger than the allowable incident angle of the second angle limiting filter31.

Therefore, the third stray light component SL3and the fourth stray light component SL4are satisfactorily blocked by the second angle limiting filter31. Thus, the second light receiving element61can limit the incidence of the third stray light component SL3and the fourth stray light component SL4on the light receiving surface30aof the sensor30through the second angle limiting filter31.

The second light receiving element61is configured similar to the first light receiving element51.

The second light receiving element61has a plurality of light receiving regions including a first light receiving region IA2, a second light receiving region IB2, and a third light receiving region IC2. Hereinafter, the first light receiving region IA2, the second light receiving region IB2, and the third light receiving region IC2are collectively referred to as “each of the light receiving regions IA2, IB2, and IC2” unless particularly specified.

Each of the light receiving regions IA2, IB2, and IC2corresponds to a part of the light receiving surface30aof the sensor30of the second light receiving element61. The light receiving regions IA2, IB2, and IC2are arranged on the light receiving surface30aone by one on the +X side in this order.

In the present embodiment, the number (3) of light receiving regions of the second light receiving element61differs from the number (4) of light receiving regions of the first light receiving element51.

The second angle limiting filter31is configured similar to the first angle limiting filter21. The second angle limiting filter31includes a first limiting region31A, a second limiting region31B, and a third limiting region31C. Hereinafter, the first limiting region31A, the second limiting region31B, and the third limiting region31C are collectively referred to as “each of the limiting regions31A,31B, and31C” unless particularly specified.

The limiting regions31A,31B, and31C correspond respectively to the light receiving regions IA2, IB2, and IC2.

The first limiting region31A is arranged to overlap the first light receiving region IA2when viewed in plan from the +Z side and limits the angle of incidence of the red light LR or the near-infrared light LI with respect to the first light receiving region IA2of the second light receiving element61.

The second limiting region31B is arranged to overlap the second light receiving region IB2when viewed in plan from the +Z side and limits the angle of incidence of the red light LR or the near-infrared light LI with respect to the second light receiving region IB2of the second light receiving element61.

The third limiting region31C is arranged to overlap the third light receiving region IC2when viewed in plan from the +Z side and limits the angle of incidence of the red light LR or the near-infrared light LI with respect to the third light receiving region IC2of the second light receiving element61.

In the detecting device3of the present embodiment, the degree of angle limitation of each of the limiting regions31A,31B, and31C progressively decreases away from the light emitting elements60and70.

The second angle limiting filter31includes a silicon oxide layer34and a plurality of light shielding walls (second light shielding walls)35embedded in the silicon oxide layer34. Each light shielding wall35is formed in a plate shape extending to the +Z side from the light receiving surface30aof the sensor30. Although omitted inFIG.7, the plurality of light shielding walls35are arranged not only in the X-axis direction but also in the Y-axis direction such that they form a grid shape as a whole when viewed in plan from the +Z side.

The second angle limiting filter31is formed through a wiring forming process of a semiconductor process similar to that of the first angle limiting filter21.

The plurality of light shielding walls35include light shielding walls35a,35b,35c, and35d.

The light shielding walls35aand35bdefine the first limiting region31A in the X-axis direction. The light shielding walls35band35cdefine the second limiting region31B in the X-axis direction. The light shielding walls35cand35ddefine the third limiting region31C in the X-axis direction. The degrees of angle limitation of the limiting regions31A,31B, and31C are defined by the X-axis intervals between adjacent light shielding walls.

In the present embodiment, the X-axis interval between the adjacent light shielding walls35band35cin the second limiting region31B among the plurality of light shielding walls35is larger than the X-axis interval between the adjacent light shielding walls35aand35bin the first limiting region31A among the plurality of light shielding walls35.

The X-axis interval between the adjacent light shielding walls35cand35din the third limiting region31C among the plurality of light shielding walls35is larger than the X-axis interval between the adjacent light shielding walls35band35cin the second limiting region31B among the plurality of light shielding walls35.

In the case of the present embodiment, for example, the interval between the light shielding walls35aand35bis set to 4.5 μm, the interval between the light shielding walls35band35cis set to 6 μm, and the interval between the light shielding walls35cand35dis set to 7.5 μm. The heights of the light shielding walls35a,35b,35c, and35dare set to 5 μm.

The second light receiving element61of the present embodiment is provided with the second angle limiting filter31such that the degree of angle limitation (the allowable incident angle) of the second light receiving element61decreases toward the +X side away from the light emitting elements60and70as illustrated inFIG.7.

Here, the light emitting elements50,60, and70(the light emitting unit11) that emit green light LG, red light LR, and near-infrared light LI are arranged at the same position in the X-axis direction, while the second light receiving element61that receives red light LR or near-infrared light LI is arranged at a position spaced to the +X side further than the first light receiving element51that receives green light LG is as illustrated inFIG.5.

Thus, the second light receiving element61is arranged at a position spaced further from the light emitting unit11in the X-axis direction than the first light receiving element51is, such that the angle of incidence of red light LR or near-infrared light LI with respect to the second light receiving element61is larger than the angle of incidence of green light LG with respect to the first light receiving element51.

In the case of the present embodiment, the degree of angle limitation of the first limiting region31A in the second angle limiting filter31is smaller than the degree of angle limitation of the first limiting region21A in the first angle limiting filter21. Specifically, the X-axis interval between the adjacent light shielding walls35aand35bin the first limiting region31A is larger than the X-axis interval between the adjacent light shielding walls25aand25bin the first limiting region21A.

That is, the allowable incident angle of the first limiting region31A in the second angle limiting filter31is larger than the allowable incident angle of the first limiting region21A in the first angle limiting filter21. Making the allowable incident angle of the first limiting region31A located on the light emitting unit11side in the second angle limiting filter31larger relative to that of the first limiting region21A in the first angle limiting filter21in this manner ensures that red light LR or near-infrared light LI that is incident at a larger angle with respect to the second light receiving element61can be incident on the light receiving surface30aof the sensor30without being blocked as described above.

Because red light LR or near-infrared light LI that have propagated in the blood vessel M1is emitted from the living body while being scattered as illustrated inFIG.5, the red light LR or near-infrared light LI has scattering components. A part of the scattering components includes scattering components LR1and LI1directed to the +X side of specular reflection components from the living body.

The scattering components LR1and LI1have a larger incident angle with respect to the second light receiving element61than the specular reflection components of red light LR or near-infrared light LI that are emitted after propagating in the blood vessel M1.

In the second angle limiting filter31of the present embodiment, the degree of angle limitation of the second light receiving element61(the light receiving surface30aof the sensor30) decreases toward the +X side, such that the allowable incident angle on the +X side is larger than the allowable incident angle on the −X side.

Thus, the second angle limiting filter31can allow the scattering components LR1and LI1to be incident on the light receiving surface30aof the sensor30, for example, via the second limiting region31B or the third limiting region31C which is located on the +X side and has a relatively large allowable incident angle.

According to the second light receiving element61of the present embodiment, the second angle limiting filter31whose degree of angle limitation decreases toward the +X side away from the light emitting elements60and70is provided, such that it is possible to inject the scattering components LR1and LI1, which are blocked by the angle limiting filter of the related art, into the sensor30.

Thus, the second light receiving element61reduces variations in the amount of received light over the light receiving surface30aof the sensor30, such that red light LR or near-infrared light LI emitted from the light emitting unit11is efficiently injected into the sensor30, thus achieving high detection accuracy.

Further, in the detecting device3of the present embodiment, the distance D1between the first light emitting element50and the first light receiving element51is smaller than the distance between the second light emitting element60or the third light emitting element70and the second light receiving element61(the distance D2or D3).

In the case of the present embodiment, the first light receiving element51is arranged at a position closest to the first light emitting element50, such that it can efficiently receive green light LG that is incident on the first light receiving element51after propagating in the living body. Red light LR and near-infrared light LI can propagate further in the living body than the green light LG as described above. Therefore, the second light receiving element61can efficiently receive the red light LR and the near-infrared light LI that have propagated a longer distance in the living body than the green light LG.

Thus, the detecting device3of the present embodiment can accurately detect green light LG, red light LR, and near-infrared light LI that have propagated in the living body through the light receiving unit12.

In the detecting device3of the present embodiment, the distance that the red light LR and the near-infrared light LI propagates in the living body until they are incident on the second light receiving element61is larger than the distance that the green light LG propagates in the living body until it is incident on the first light receiving element51.

The green light LG can propagate only a short distance in the living body, compared to the red light LR or the near-infrared light LI as described above. Therefore, if the green light LG propagates in the living body such that it can reach the second light receiving element61, the green light LG is sufficiently attenuated while passing through the living body. Thus, the green light LG cannot be incident on the second light receiving element61.

On the other hand, the red light LR and the near-infrared light LI can propagate further in the living body than the green light LG. Therefore, even when the red light LR and the near-infrared light LI have propagated a longer distance in the living body than the green light LG, a sufficient amount of the red light LR and the near-infrared light LI can be incident on the second light receiving element61spaced further from the light emitting unit11.

In the case of the present embodiment, only the red light LR and the near-infrared light LI are incident on the second light receiving element61, such that it is not necessary to provide the second light receiving element61with a band pass filter that selectively transmits the red light LR and the near-infrared light LI and blocks the green light LG. That is, the detecting device3of the present embodiment can adopt the above configuration in which only the first light receiving element51includes the bandpass filter22while the second light receiving element61does not include a bandpass filter. Thus, the detecting device3of the present embodiment can omit a bandpass filter for the second light receiving element61, reducing the cost.

The first light receiving element51of the present embodiment can make it difficult for the first stray light component SL1and the second stray light component SL2to be incident on the light receiving surface20aof the sensor20. Thus, the first light receiving element51can limit the incidence of the first stray light component SL1and the second stray light component SL2, which are noise components, achieving a high S/N ratio.

The second light receiving element61of the present embodiment can also make it difficult for the third stray light component SL3and the fourth stray light component SL4to be incident on the light receiving surface30aof the sensor30. Thus, the second light receiving element61can limit the incidence of the third stray light component SL3and the fourth stray light component SL4, which are noise components, achieving a high S/N ratio.

The detecting device3of the present embodiment can greatly improve the detection accuracy of the light receiving unit12by increasing the amount of received light while increasing the S/N ratio as described above. Thus, the detecting device3of the present embodiment enables highly accurate light reception by the light receiving elements51and61, such that it is possible to reduce power consumption of the light emitting unit11by limiting the amount of light emission from the light emitting elements50,60and70.

The measuring device100of the present embodiment includes the above detecting device3and thus can provide a biometric measuring device capable of highly accurate detection while reducing power consumption.

Second Embodiment

Subsequently, a detecting device of a second embodiment will be described. The detecting device of the present embodiment differs from that of the first embodiment in the configurations of the first and second angle limiting filters which are angle limiting members. Hereinafter, the same reference numerals will be used for the components and members common with the first embodiment and reference numerals will be omitted for details.

FIG.8is a cross-sectional view illustrating a configuration of a main part of a detecting device103of the present embodiment.

As illustrated inFIG.8, the detecting device103of the present embodiment includes a light emitting unit11, a light receiving unit112, a case40, and a sealing layer42. The light receiving unit112of the present embodiment includes a first light receiving element151and a second light receiving element161.

The first light receiving element151includes a sensor20, a first angle limiting filter (angle limiting member)81, and a bandpass filter22. The second light receiving element161includes a sensor30and a second angle limiting filter (angle limiting member)91.

In the detecting device103of the present embodiment, the first light receiving element151includes a first light receiving region IA11, a second light receiving region IB11, and a third light receiving region IC11. Hereinafter, the first light receiving region IA11, the second light receiving region IB11, and the third light receiving region IC11are collectively referred to as “each of the light receiving regions IA11, IB11, and IC11” unless particularly specified.

Each of the light receiving regions IA11, IB11, and IC11corresponds to a part of the light receiving surface20aof the sensor20of the first light receiving element151. The light receiving regions IA11, IB11, and IC11are arranged on the light receiving surface20aof the sensor20one by one on the +X side in this order.

The first angle limiting filter81includes a first limiting region81A, a second limiting region81B, and a third limiting region81C. Hereinafter, the first limiting region81A, the second limiting region81B, and the third limiting region81C are collectively referred to as “each of the limiting regions81A,81B, and81C” unless particularly specified.

The limiting regions81A,81B, and81C correspond respectively to the light receiving regions IA11, IB11, and IC11. In the detecting device103of the present embodiment, the degree of angle limitation of each of the limiting regions81A,81B, and81C progressively decreases away from the first light emitting element50.

The first angle limiting filter81includes a silicon oxide layer84and a plurality of light shielding walls (first light shielding walls)85embedded in the silicon oxide layer84. In the first angle limiting filter81, the plurality of light shielding walls85are provided on the light receiving regions IA11, IB11, and IC11of the first light receiving element151. The plurality of light shielding walls85include light shielding walls85a,85b,85c,85d,85e,85f, and85g.

The light shielding wall85aand the light shielding wall85bare arranged in the X-axis direction in the first limiting region81A. In the case of the present embodiment, the heights of the light shielding walls85aand85bare set to, for example, 5 μm.

The light shielding wall85cand the light shielding wall85dare arranged in the X-axis direction in the second limiting region81B. In the case of the present embodiment, the heights of the light shielding walls85cand85dare set to, for example, 4 μm.

The light shielding wall85e, the light shielding wall85f, and the light shielding wall85gare arranged in the X-axis direction in the third limiting region81C. In the case of the present embodiment, the heights of the light shielding walls85e,85f, and85gare set to, for example, 3 μm.

The X-axis intervals between adjacent ones of the light shielding walls85a,85b,85c,85d,85e,85f, and85gare set to, for example, 3 μm.

The first angle limiting filter81of the present embodiment can be formed, for example, by providing portions in which conductive plugs such as tungsten plugs having light absorptivity are embedded and portions in which no conductive plugs are embedded through multiple steps into which a wiring forming process of a semiconductor process is divided, such that a plurality of light shielding walls85with different heights are embedded in the silicon oxide layer24.

In the case of the present embodiment, the degrees of angle limitation of the limiting regions81A,81B, and81C are defined by the heights of light shielding walls arranged in the X-axis direction.

In the present embodiment, the height of the light shielding walls85cand85darranged in the X-axis direction in the second limiting region81B among the plurality of light shielding walls85is less than the height of the light shielding walls85aand85barranged in the X-axis direction in the first limiting region81A among the plurality of light shielding walls85.

The height of the light shielding walls85e,85f, and85garranged in the X-axis direction in the third limiting region81C among the plurality of light shielding walls85is also less than the height of the light shielding walls85cand85darranged in the X-axis direction in the second limiting region81B among the plurality of light shielding walls85.

The allowable incident angle of the second limiting region81B is larger than the allowable incident angle of the first limiting region81A because the height of the light shielding walls of the second limiting region81B is less than that of the first limiting region81A as illustrated inFIG.8.

In the first angle limiting filter81of the present embodiment, the heights of light shielding walls arranged in the X-axis direction are adjusted as described above such that the degree of angle limitation of the second limiting region81B is smaller than the degree of angle limitation of the first limiting region81A.

The allowable incident angle of the third limiting region81C is larger than the allowable incident angle of the second limiting region81B because the height of the light shielding walls of the third limiting region81C is less than that of the second limiting region81B.

In the first angle limiting filter81of the present embodiment, the heights of light shielding walls arranged in the X-axis direction are adjusted as described above such that the degree of angle limitation of the third limiting region81C is smaller than the degree of angle limitation of the second limiting region81B.

The first light receiving element151of the present embodiment is provided with the first angle limiting filter81such that the degree of angle limitation (the allowable incident angle) of the first light receiving element151decreases toward the +X side away from the first light emitting element50as described above.

The first angle limiting filter81of the present embodiment can allow the scattering components LG1to be incident on the light receiving surface20aof the sensor20, for example, via the second limiting region81B or the third limiting region81C having a relatively large allowable incident angle.

According to the first light receiving element151of the present embodiment, the first angle limiting filter81whose degree of angle limitation decreases toward the +X side away from the first light emitting element50is provided, such that it is possible to inject the scattering components LG1, which are blocked by the angle limiting filter of the related art, into the sensor20. Thus, the first light receiving element151reduces variations in the amount of received light over the light receiving surface20aof the sensor20to efficiently inject green light LG emitted from the light emitting unit11into the sensor20, thus achieving high detection accuracy.

The second light receiving element161is configured similar to the first light receiving element151.

The second light receiving element161has a plurality of light receiving regions including a first light receiving region IA21, a second light receiving region IB21, and a third light receiving region IC21. Hereinafter, the first light receiving region IA21, the second light receiving region IB21, and the third light receiving region IC21are collectively referred to as “each of the light receiving regions IA21, IB21, and IC21” unless particularly specified.

Each of the light receiving regions IA21, IB21, and IC21corresponds to a part of the light receiving surface30aof the sensor30of the second light receiving element161. The light receiving regions IA21, IB21, and IC21are arranged on the light receiving surface30aof the sensor30one by one on the +X side in this order.

The second angle limiting filter91is configured similar to the first angle limiting filter81. The second angle limiting filter91includes a first limiting region91A, a second limiting region91B, and a third limiting region91C. Hereinafter, the first limiting region91A, the second limiting region91B, and the third limiting region91C are collectively referred to as “each of the limiting regions91A,91B, and91C” unless particularly specified.

The limiting regions91A,91B, and91C correspond respectively to the light receiving regions IA21, IB21, and IC21. In the detecting device103of the present embodiment, the degree of angle limitation of each of the limiting regions91A,91B, and91C progressively decreases away from the light emitting elements60and70.

The second angle limiting filter91includes a silicon oxide layer94and a plurality of light shielding walls (second light shielding walls)95embedded in the silicon oxide layer94. In the second angle limiting filter91, the plurality of light shielding walls95are provided on the light receiving regions IA21, IB21, and IC21of the second light receiving element161. The plurality of light shielding walls95include light shielding walls95a,95b,95c,95d,95e,95f, and95g. The second angle limiting filter91is formed by embedding a plurality of light shielding walls95with different heights in the silicon oxide layer24through multiple steps into which a wiring forming process of a semiconductor process is divided, similar to the first angle limiting filter81.

The light shielding wall95aand the light shielding wall95bare arranged in the X-axis direction in the first limiting region91A. In the case of the present embodiment, the heights of the light shielding walls95aand95bare set to, for example, 4 μm.

The light shielding wall95cand the light shielding wall95dare arranged in the X-axis direction in the second limiting region91B. In the case of the present embodiment, the heights of the light shielding walls95cand95dare set to, for example, 3 μm.

The light shielding wall95e, the light shielding wall95f, and the light shielding wall95gare arranged in the X-axis direction in the third limiting region91C. In the case of the present embodiment, the heights of the light shielding walls95e,95f, and95gare set to, for example, 2 μm.

The X-axis intervals between adjacent ones of the light shielding walls95a,95b,95c,95d,95e,95f, and95gare set to, for example, 3 μm.

In the case of the present embodiment, the degrees of angle limitation of the limiting regions91A,91B, and91C are defined by the heights of light shielding walls arranged in the X-axis direction.

In the present embodiment, the height of the light shielding walls95cand95darranged in the X-axis direction in the second limiting region91B among the plurality of light shielding walls95is less than the height of the light shielding walls95aand95barranged in the X-axis direction in the first limiting region91A among the plurality of light shielding walls95.

The height of the light shielding walls95e,95f, and95garranged in the X-axis direction in the third limiting region91C among the plurality of light shielding walls95is also less than the height of the light shielding walls95cand95darranged in the X-axis direction in the second limiting region91B among the plurality of light shielding walls95.

In the second angle limiting filter91of the present embodiment, the heights of light shielding walls arranged in the X-axis direction are adjusted as described above such that the degree of angle limitation (the allowable incident angle) of the second light receiving element161decreases toward the +X side away from the light emitting elements60and70as illustrated inFIG.8.

In the case of the present embodiment, the degree of angle limitation of the first limiting region91A in the second angle limiting filter91is smaller than the degree of angle limitation of the first limiting region81A in the first angle limiting filter81. Specifically, the height of the light shielding walls95aand95barranged in the X-axis direction in the first limiting region91A of the second light receiving element161is less than the height of the light shielding walls85aand85barranged in the X-axis direction in the first limiting region81A of the first light receiving element151.

That is, the allowable incident angle of the first limiting region91A in the second angle limiting filter91is larger than the allowable incident angle of the first limiting region81A in the first angle limiting filter81. Making the allowable incident angle of the first limiting region91A located on the light emitting unit11side (the −X side) in the second angle limiting filter91larger relative to that of the first limiting region81A in the first angle limiting filter81in this manner ensures that red light LR or near-infrared light LI that is incident at a larger angle with respect to the second light receiving element161can be incident on the light receiving surface30aof the sensor30without being blocked.

According to the second light receiving element161of the present embodiment, the second angle limiting filter91whose degree of angle limitation decreases toward the +X side away from the light emitting elements60and70is provided, such that it is possible to inject the scattering components LR1and LI1, which are blocked by the angle limiting filter of the related art, into the sensor30.

Thus, the second light receiving element161reduces variations in the amount of received light over the light receiving surface30aof the sensor30to efficiently inject red light LR or near-infrared light LI emitted from the light emitting unit11into the sensor30, thus achieving high detection accuracy.

Similar to the detecting device3of the above embodiments, the detecting device103of the present embodiment can improve the detection accuracy of the light receiving unit112by increasing the amount of received light while increasing the S/N ratio as described above. Thus, the measuring device using the detecting device103according to the present embodiment can provide a biometric measuring device capable of highly accurate detection while reducing power consumption.

EXAMPLES

In order to demonstrate the effects of the detecting devices3and103of the above embodiments, the present inventor has simulated both the amount of light received by the light receiving element according to the distance from the light emitting unit and the light receiving rate of the light receiving element for a first example, a second example, and a comparative example that will be described below.

Specifically, the detecting device3of the first embodiment was used as the first example, the detecting device103of the second embodiment was used as the second example, and a detecting device using an angle limiting filter in which light shielding walls are embedded at equal intervals was used as the comparative example.

In the angle limiting filter of the detecting device of the comparative example, for example, the intervals between adjacent light shielding walls were set to 3 μm and the heights of the light shielding walls were set to 5 μm.

A graph ofFIG.9shows the results of simulating the amount of light received by the light receiving element according to the distance from the light emitting unit for the detecting devices of the first example, the second example, and the comparative example. InFIG.9, the horizontal axis of the graph represents the distance from the light emitting unit in the direction in which the light emitting unit and the light receiving unit are arranged (for example, the X-axis direction inFIG.5) and the vertical axis of the graph represents the amount of light received by the light receiving element.

As shown inFIG.9, it was confirmed that the amount of light received by the light receiving element increased as the distance from the light emitting unit increased in the detecting devices of the first and second examples, relative to the detecting device of the comparative example. That is, it was confirmed that the detecting devices of the first and second examples can make the amount of received light uniform over the surface of the light receiving element by decreasing the degree of angle limitation of the angle limiting filter as the distance from the light emitting unit increases.

A graph ofFIG.10shows the results of simulating the light receiving rate of the light receiving element for the detecting devices of the first example, the second example, and the comparative example.FIG.10shows the amount of received light for each of the detecting devices of the first and second examples when the amount of light received by the light receiving element of the detecting device of the comparative example is set to 1.0.

As shown inFIG.10, it was confirmed that the detecting devices of the first and second examples can increase the amount of light received by the light receiving element to 1.36 or 1.27 relative to the detecting device of the comparative example.

From the results shown inFIGS.9and10, it was confirmed that the detecting device of the first example has a higher effect of increasing the amount of light received by the light receiving element compared to the detecting device of the second example.

From the above, it has been demonstrated that the detecting devices3and103of the above embodiments can increase the amount of light received by each light receiving element, compared to the detecting device of the comparative example.

Although the present disclosure has been described above based on the above embodiments, the present disclosure is not limited to the above embodiments and can be implemented in various modes without departing from the spirit of the disclosure.

For example, although a living body is exemplified by a human in the above embodiments, the present disclosure can also be applied to measurement of the biological information (for example, pulse) of other animals.

Although the measuring device100of the first embodiment has been described with respect to the case where the detecting device3is provided in the main body1as an example, the installation location of the detecting device3is not limited to this, and for example, the detecting device3may be embedded in the back side of the belt.

Although the measuring device100of the first embodiment has been described with respect to a configuration in which it is of a wristwatch type as an example, the present disclosure can also be applied to, for example, a configuration in which it is worn on the subject's neck as a necklace type or a configuration in which it is attached to the subject's body as a sealed type, or a configuration in which it is attached to the subject's head as a head-mounted display type.

Although the detecting device3of the first embodiment has been described with respect to the case where the sensor20of the first light receiving element51includes four light receiving regions as an example, the number of light receiving regions is not limited to this. For example, the sensor20only needs to include at least two light receiving regions (the first light receiving region IA1and the second light receiving region IB1) and may also include five or more light receiving regions. Similarly, the sensor30of the second light receiving element61only needs to include at least two light receiving regions (the first light receiving region IA2and the second light receiving region IB2) and may also include five or more light receiving regions.

Although the detecting device103of the second embodiment has been described with respect to the case where the sensor20of the first light receiving element151includes three light receiving regions as an example, the sensor20of the first light receiving element151only needs to include at least two light receiving regions (the first light receiving region IA11and the second light receiving region IB11) and may also include five or more light receiving regions. Similarly, the sensor30of the second light receiving element161only needs to include at least two light receiving regions (the first light receiving region IA21and the second light receiving region IB21) and may also include five or more light receiving regions.

Although the detecting device3of the first embodiment has been described with respect to the case where each of the light emitting elements50,60, and70is caused to emit light in a time division manner as an example, the first light emitting element50may be constantly lit rather than being lit in a time division manner because the first light receiving element51corresponding to green light LG of the first light emitting element50is individually provided. Similarly, the first light emitting element50in the second embodiment may be constantly lit rather than being lit in a time division manner.

A detecting device of an aspect of the present disclosure may be configured as follows.

The detecting device of the aspect of the present disclosure includes a light emitting portion that emits light and a light receiving portion including an angle limiting member that limits an angle of incidence of light from the light emitting portion, wherein the light receiving portion has a first light receiving region and a second light receiving region that is spaced further from the light emitting portion than the first light receiving region is, the angle limiting member includes a first limiting region corresponding to the first light receiving region and a second limiting region corresponding to the second light receiving region, and a degree of angle limitation of the second limiting region is smaller than a degree of angle limitation of the first limiting region.

The detecting device of the aspect of the present disclosure may be configured such that, when a direction in which the light emitting portion and the light receiving portion are arranged is defined as a first direction, the angle limiting member includes a plurality of light shielding walls provided in the light receiving portion, and an interval in the first direction between adjacent light shielding walls in the second limiting region among the plurality of light shielding walls is larger than an interval in the first direction between adjacent light shielding walls in the first limiting region among the plurality of light shielding walls.

The detecting device of the aspect of the present disclosure may be configured such that the light emitting portion includes a first light emitting element configured to emit first light having a green wavelength band and a second light emitting element provided in a second direction intersecting the first direction with respect to the first light emitting element and configured to emit second light having a wavelength band longer than those of the green wavelength band, the light receiving portion includes a first light receiving element configured to receive the first light from the first light emitting element and a second light receiving element configured to receive the second light from the second light emitting element, and the first light receiving element is provided closer to the light emitting portion in the first direction than the second light receiving element is.

The detecting device of the aspect of the present disclosure may be configured such that the angle limiting member includes a first angle limiting filter configured to limit an angle of incidence of the first light with respect to the first light receiving element and a second angle limiting filter configured to limit an angle of incidence of the second light with respect to the second light receiving element, and a degree of angle limitation of the first limiting region in the second angle limiting filter is smaller than a degree of angle limitation of the first limiting region in the first angle limiting filter.

The detecting device of the aspect of the present disclosure may be configured such that the first angle limiting filter includes a plurality of first light shielding walls provided in the first light receiving element, the second angle limiting filter includes a plurality of second light shielding walls provided in the second light receiving element, and an interval in the first direction between adjacent ones of the second light shielding walls in the first limiting region of the second light receiving element is larger than an interval in the first direction between adjacent ones of the first light shielding walls in the first limiting region of the first light receiving element.

The detecting device of the aspect of the present disclosure may be configured such that, when a direction in which the light emitting portion and the light receiving portion are arranged is defined as a first direction, the angle limiting member includes a plurality of light shielding walls provided in the light receiving portion, and a height of the light shielding walls arranged in the first direction in the second limiting region is less than a height of the light shielding walls arranged in the first direction in the first limiting region.

The detecting device of the aspect of the present disclosure may be configured such that the light emitting portion includes a first light emitting element configured to emit first light having a green wavelength band and a second light emitting element provided in a second direction intersecting the first direction with respect to the first light emitting element and configured to emit second light having a wavelength band longer than those of the green wavelength band, the light receiving portion includes a first light receiving element configured to receive the first light from the first light emitting element and a second light receiving element configured to receive the second light from the second light emitting element, and the first light receiving element is provided closer to the light emitting portion in the first direction than the second light receiving element is.

The detecting device of the aspect of the present disclosure may be configured such that the angle limiting member includes a first angle limiting filter configured to limit an angle of incidence of the first light with respect to the first light receiving element and a second angle limiting filter configured to limit an angle of incidence of the second light with respect to the second light receiving element, and a degree of angle limitation of the first limiting region in the second angle limiting filter is smaller than a degree of angle limitation of the first limiting region in the first angle limiting filter.

The detecting device of the aspect of the present disclosure may be configured such that the first angle limiting filter includes a plurality of first light shielding walls provided in the first light receiving element, the second angle limiting filter includes a plurality of second light shielding walls provided in the second light receiving element, and a height of the second light shielding walls arranged in the first direction in the first limiting region of the second light receiving element is less than a height of the first light shielding walls arranged in the first direction in the first limiting region of the first light receiving element.

The detecting device of the aspect of the present disclosure may be configured such that the light receiving portion further includes a third light receiving region that is spaced further from the light emitting portion than the second light receiving region is, and the angle limiting member further includes a third limiting region corresponding to the third light receiving region and having a smaller degree of angle limitation than the second limiting region.

A detecting device of an aspect of the present disclosure may be configured as follows.

The detecting device of the aspect of the present disclosure includes a light emitting portion configured to emit light to a living body, a light receiving portion arranged in a first direction with respect to the light emitting portion and configured to receive light from the living body, and a plurality of light shielding walls arranged in the first direction and configured to limit an angle of incidence of light on the light receiving portion, wherein an interval between the light shielding walls in a region far from the light emitting portion is larger than an interval between the light shielding walls in a region close to the light emitting portion.

A measuring device of an aspect of the present disclosure may be configured as follows.

The measuring device of the aspect of the present disclosure includes the detecting device according to the above aspect and an information analysis unit configured to identify biological information from a detection signal indicating a detection result of the detecting device.