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WO2025056247A1 - Module de capteur - Google Patents

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Publication number
WO2025056247A1
WO2025056247A1 PCT/EP2024/072342 EP2024072342W WO2025056247A1 WO 2025056247 A1 WO2025056247 A1 WO 2025056247A1 EP 2024072342 W EP2024072342 W EP 2024072342W WO 2025056247 A1 WO2025056247 A1 WO 2025056247A1
Authority
WO
WIPO (PCT)
Prior art keywords
emitter
detector
sensor module
electromagnetic radiation
main
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2024/072342
Other languages
English (en)
Inventor
Klaus Flock
Timm MUELLER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ams Osram AG
Original Assignee
Ams Osram AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ams Osram AG filed Critical Ams Osram AG
Publication of WO2025056247A1 publication Critical patent/WO2025056247A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/40—Optical elements or arrangements
    • H10F77/407—Optical elements or arrangements indirectly associated with the devices
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/02—Detecting, measuring or recording for evaluating the cardiovascular system, e.g. pulse, heart rate, blood pressure or blood flow
    • A61B5/024—Measuring pulse rate or heart rate
    • A61B5/02416—Measuring pulse rate or heart rate using photoplethysmograph signals, e.g. generated by infrared radiation
    • A61B5/02427—Details of sensor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
    • A61B5/14552—Details of sensors specially adapted therefor
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F55/00—Radiation-sensitive semiconductor devices covered by groups H10F10/00, H10F19/00 or H10F30/00 being structurally associated with electric light sources and electrically or optically coupled thereto
    • H10F55/20—Radiation-sensitive semiconductor devices covered by groups H10F10/00, H10F19/00 or H10F30/00 being structurally associated with electric light sources and electrically or optically coupled thereto wherein the electric light source controls the radiation-sensitive semiconductor devices, e.g. optocouplers
    • H10F55/25—Radiation-sensitive semiconductor devices covered by groups H10F10/00, H10F19/00 or H10F30/00 being structurally associated with electric light sources and electrically or optically coupled thereto wherein the electric light source controls the radiation-sensitive semiconductor devices, e.g. optocouplers wherein the radiation-sensitive devices and the electric light source are all semiconductor devices
    • H10F55/255—Radiation-sensitive semiconductor devices covered by groups H10F10/00, H10F19/00 or H10F30/00 being structurally associated with electric light sources and electrically or optically coupled thereto wherein the electric light source controls the radiation-sensitive semiconductor devices, e.g. optocouplers wherein the radiation-sensitive devices and the electric light source are all semiconductor devices formed in, or on, a common substrate
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F77/00—Constructional details of devices covered by this subclass
    • H10F77/30—Coatings
    • H10F77/306—Coatings for devices having potential barriers
    • H10F77/331—Coatings for devices having potential barriers for filtering or shielding light, e.g. multicolour filters for photodetectors

Definitions

  • a sensor module is speci fied herein .
  • At least one obj ect of certain embodiments is to speci fy a sensor module with an improved sensitivity . This obj ect is achieved by the sensor module according to the independent claim .
  • the sensor module comprises an emitter that emits electromagnetic radiation during operation .
  • the emitter at least partially converts an electric operating current into the electromagnetic radiation .
  • the emitter comprises a semiconductor layer sequence with a pn-j unction for converting the electric operating current into the electromagnetic radiation during operation .
  • the electromagnetic radiation comprises wavelengths in a spectral range between infrared light and ultraviolet light .
  • the electromagnetic radiation emitted by the emitter comprises or consists of electromagnetic laser radiation .
  • electromagnetic laser radiation is generated by stimulated emission .
  • electromagnetic laser radiation has a longer coherence length, a smaller spectral bandwidth, and/or a higher degree of polari zation, for example .
  • the sensor module comprises a detector that detects electromagnetic radiation emitted by the emitter during operation .
  • the detector at least partially converts incident electromagnetic radiation emitted by the emitter into an electric voltage and/or an electric current .
  • the detector comprises a semiconductor layer sequence with a pn-j unction for converting the incident electromagnetic radiation into the electric voltage and/or the electric current during operation .
  • the emitter and the detector are arranged on a carrier .
  • the emitter and the detector are arranged on a common carrier .
  • the emitter and the detector are arranged laterally adj acent to each other on a main surface of the carrier .
  • the main surface of the carrier is flat .
  • lateral refers to a direction parallel to the main surface of the carrier .
  • the main surface of the carrier is curved .
  • the main surface of the carrier has a convex shape .
  • the carrier comprises or consists of a semiconductor substrate or a printed circuit board .
  • the carrier comprises electrical contact pads on the main surface for electrically contacting the emitter and/or the detector .
  • the emitter and the detector are surface mountable .
  • the emitter and the detector are arranged such that a light emission surface of the emitter and a light transmitting surface of the detector are facing away from the carrier.
  • the light emission surface and the light transmitting surface are flat surfaces.
  • the emitter and the detector are arranged on different sides of the carrier.
  • the emitter is arranged or mounted on the main surface of the carrier and the detector is arranged or mounted on a surface of the carrier that is opposite to the main surface, or vice versa .
  • a main emission direction of the emitter and a main detection direction of the detector are inclined away from each other.
  • the main emission direction and the main detection direction are not parallel to each other.
  • an angle between the main emission direction and the main detection direction is larger than 0° and smaller than 180°, or between 40° and 140°, inclusive, or between 60° and 120°, inclusive, or between 80° and 100°, inclusive, or is 90°.
  • the main emission direction and the main detection direction do not cross in a hal f space above the main surface of the carrier .
  • the main emission direction and the main detection direction cross in a hal f space above the main surface of the carrier .
  • the emitter and the detector are remotely mounted and imaged onto an obj ect to be sensed using e . g . a proj ection optics .
  • the sensor module is configured as a biomonitoring sensor and the emitter and the detector are imaged onto biological tissue , such as skin, using the proj ection optics .
  • the sensor module is part of an augmented reality and/or virtual reality headset .
  • the main emission direction of the emitter corresponds to a direction where a directional characteristics of the emitter or a directivity of the emitter is maximal .
  • the directional characteristics of the emitter speci fies a power of the emitted electromagnetic radiation per unit solid angle .
  • the main emission direction is perpendicular to the light emission surface of the emitter .
  • the main detection direction of the detector corresponds to a direction where a directional characteristics of the detector or a directivity of the detector is maximal .
  • the directional characteristics of the detector speci fies a sensitivity of the detector as function of the solid angle .
  • the main detection direction is perpendicular to the light transmitting surface of the detector .
  • the main detection direction is defined as a direction against the propagation direction of the electromagnetic radiation incident on the detector. In other words, the main detection direction is defined as pointing away from the detector rather than towards the detector.
  • the main emission direction and/or the main detection direction has a polar angle larger than 0° and smaller than 90°, or between 10° and 80°, inclusive, or between 20° and 70°, inclusive, or between 30° and 60°, inclusive, for example.
  • the main emission direction and/or the main detection direction has a polar angle of 45°.
  • the main emission direction has an azimuthal angle larger than 90° and smaller than 270°, or larger than 135° and smaller than 225°, for example, whereas the main detection direction has an azimuthal angle larger than -90° and smaller than 90°, or larger than -45° and smaller than 45°, for example.
  • the main emission direction has an azimuthal angle of 180° and the main detection direction has an azimuthal angle of 0°.
  • the sensor module comprises:
  • the emitter and the detector are arranged on the carrier, and - the main emission direction of the emitter and the main detection direction of the detector are inclined away from each other .
  • the sensor module described herein is based on the idea to arrange the emitter and the detector such that the main emission direction and the main detection direction are inclined away from each other, such that the sensitivity and/or a signal-to-noise ratio of the sensor module can be increased compared to a sensor module where the main emission direction and the main detection direction are parallel to each other .
  • a higher sensitivity of the sensor module advantageously lowers signal-to-noise ratio requirements of the sensor module , for example , and thus makes it possible to operate the sensor module with reduced power, prolonging battery li fe and/or reducing the overall system form factor, for example .
  • the sensor module is a biomonitoring sensor configured for measuring a pulse and/or a blood oxygen saturation of a person or an animal .
  • the sensor module emits electromagnetic radiation that is at least partially reflected at and/or inside a biological tissue , such as skin, and subsequently detected by the detector .
  • the sensor module is part of a wearable device , such as a watch or an in-ear earphone .
  • a separation between the emitter and the detector might be particularly small , for example at most a few millimeters . Accordingly, a substantial fraction of the electromagnetic radiation emitted by the emitter that is detected by the detector may originate from crosstalk between the emitter and the detector, and/or from a reflection at the surface of the biological tissue, for example, such that the reflected electromagnetic radiation has not interacted with deeper layers of the biological tissue. Consequently, the signal-to-noise ratio and/or the sensitivity of the sensor module can be reduced if the separation between the emitter and the detector is decreased.
  • both crosstalk and the amount of detected electromagnetic radiation that is reflected directly at the surface of the biological tissue can be decreased. Accordingly, the signal-to-noise ratio and/or the sensitivity of the sensor module can be advantageously increased.
  • the main emission direction of the emitter and/or the main detection direction of the detector is inclined with respect to a surface normal of the main surface of the carrier.
  • the polar angle of the main emission direction of the emitter is larger than 0° and smaller than 90°, or between 10° and 80°, inclusive, or between 20° and 70°, inclusive, or between 30° and 60°, inclusive, for example.
  • the polar angle of the main detection direction of the detector is larger than 0° and smaller than 90°, or between 10° and 80°, inclusive, or between 20° and 70°, inclusive, or between 30° and 60°, inclusive, for example.
  • an angle between the main emission direction of the emitter and a direction from the emitter to the detector is larger than 90 ° and smaller than 180 ° , or larger than 100 ° and smaller than 170 ° , or larger than 120 ° and smaller than 150 ° .
  • the direction from the emitter to the detector is a direction from a center of the emitter to a center of the detector .
  • an angle between the main detection direction of the detector and a direction from the detector to the emitter is larger than 90 ° and smaller than 180 ° , or larger than 100 ° and smaller than 170 ° , or larger than 120 ° and smaller than 150 ° .
  • the direction from the detector to the emitter is a direction from the center of the detector to the center of the emitter .
  • a distance between the emitter and the detector is at most 3 millimeter, or at most 2 millimeter, or at most 1 millimeter .
  • the distance is an edge-to-edge distance between the emitter and the detector .
  • the distance between the emitter and the detector is larger than 3 millimeter .
  • the distance between the emitter and the detector is at most 5 millimeter or at most 10 millimeter .
  • the emitter comprises or consists of a light emitting diode chip ( LED chip ) or a vertical cavity surface emitting laser diode chip (VCSEL chip ) .
  • the LED chip comprises a semiconductor layer stack with a pn-j unction for converting the electric operating current into electromagnetic radiation .
  • the LED chip has a Lambertian directional characteristics .
  • the LED chip is comprised by a LED package .
  • the VCSEL chip comprises a semiconductor layer stack with a pn-j unction for converting the electrical operating current into electromagnetic radiation .
  • the VCSEL chip emits electromagnetic laser radiation in a direction perpendicular to a main extension plane of the semiconductor layers of the semiconductor layer stack .
  • an optical axis of an optical resonator of the VCSEL chip is arranged perpendicular to the main extension plane of the semiconductor layers of the semiconductor layer stack .
  • the VCSEL chip has a directed directional characteristics that deviates from a Lambertian directional characteristics .
  • the VCSEL chip is comprised by a VCSEL package .
  • the emitter comprises or consists of an incandescent light source , a Xenon light source , a laser driven or laser pumped light source , or an edge emitting laser diode , for example .
  • the detector comprises or consists of a photodiode chip or a phototransistor chip .
  • the photodiode or phototransistor comprises a semiconductor layer stack with a pn-j unction for at least partially converting incident electromagnetic radiation into an electric voltage and/or an electric current .
  • the photodiode chip or the phototransistor chip is comprised by a photodiode package or a phototransistor package , respectively .
  • the electromagnetic radiation emitted by the emitter is in the infrared spectral range . It is also possible that the emitter emits electromagnetic radiation in the red or green spectral range , for example .
  • the emitter comprises a first optical element for collimating the emitted electromagnetic radiation .
  • the first optical element changes the directional characteristics and/or the main emission direction of the electromagnetic radiation emitted by the emitter .
  • the first optical element reduces a crosstalk between the emitter and the detector .
  • the first optical element is arranged of f-centered from a light emission surface of a light source of the emitter .
  • "of f-centered" refers to a lateral displacement between a center of the light source and a center of the first optical element .
  • the light source is the light emitting diode or the VCSEL .
  • the main emission direction of the emitter can be adj usted .
  • the light emission surface of the light source is arranged parallel to the main surface of the carrier, while the main emission direction of the emitter is inclined with respect to the surface normal of the main surface of the carrier .
  • the detector comprises a second optical element for focusing the electromagnetic radiation onto a light transmitting surface of a photosensitive element of the detector .
  • the photosensitive element is the photodiode or the phototransistor .
  • the second optical element changes the directional characteristics and/or the main detection direction of the detector .
  • the second optical element reduces a crosstalk between the emitter and the detector .
  • the second optical element is arranged of f-centered from the light transmitting surface of the photosensitive element .
  • "of f-centered" refers to a lateral displacement between a center of the photosensitive element and a center of the second optical element .
  • the main detection direction of the detector can be adj usted .
  • the light transmitting surface of the photosensitive element is arranged parallel to the main surface of the carrier, while the main detection direction of the detector is inclined with respect to the surface normal of the main surface of the carrier .
  • the first optical element and/or the second optical element comprises or consists of a refractive optical element or a di f fractive optical element .
  • the refractive optical element comprises or consists of a lens or a Fresnel lens .
  • the di f fractive optical element comprises or consists of a di f fraction grating or a metalens .
  • the metalens comprises a nanostructured surface with an aperiodic array of nano-pillars that imparts a spatially dependent phase onto incident electromagnetic radiation .
  • the emitter comprises a first reflective element for tuning the directional characteristics of the emitter .
  • the first reflective element comprises or consists of a mirror or a metallic layer .
  • the first reflective element has a reflective surface that is arranged inclined or perpendicular to the main surface of the carrier .
  • the reflective surface of the first reflective element is flat or curved .
  • the first reflective element is arranged on a side of the emitter facing the detector . Accordingly, the first reflective element reduces a crosstalk between the emitter and the detector, for example . Moreover, the first reflective element directs the emitted electromagnetic radiation away from the detector, for example .
  • the detector comprises a second reflective element for tuning the directional characteristics of the detector .
  • the second reflective element comprises or consists of a mirror or a metallic layer .
  • the second reflective element has a reflective surface that is arranged inclined or perpendicular to the main surface of the carrier .
  • the reflective surface of the second reflective element is flat or curved .
  • the second reflective element is arranged on a side of the detector facing the emitter . Accordingly, the second reflective element reduces a crosstalk between the emitter and the detector, for example .
  • the second reflective directs the main detection direction of the detector away from the emitter, for example .
  • a barrier for reducing crosstalk between the emitter and the detector is arranged on the main surface of the carrier .
  • the barrier comprises or consists of an absorptive material that at least partially absorbs the electromagnetic radiation emitted by the emitter .
  • an absorbance of the barrier for the electromagnetic radiation emitted by the emitter is at least 50% , or at least 80% , or at least 90% .
  • the barrier comprises or consists of a material that reflects the electromagnetic radiation emitted by the emitter .
  • the barrier has a reflectance of at least 80% , or of at least 90% , or of at least 99% for the electromagnetic radiation emitted by the emitter .
  • the barrier can be used for adj usting or changing the directional characteristics of the emitter and the detector .
  • the sensor module is configured as a photoplethysmography ( short : PPG) sensor .
  • the sensor module measures a heart rate , a blood oxygen saturation ( short : SpO2 ) , a blood pressure , and/or an arterial sti f fness during operation .
  • the sensor module further comprises a second emitter and a third emitter, wherein the emitter emits electromagnetic radiation in an infrared spectral range during operation, the second emitter emits electromagnetic radiation in a red spectral range during operation, and the third emitter emits electromagnetic radiation in a green spectral range during operation .
  • the infrared spectral range comprises wavelengths between and including 780 nanometer and 1500 nanometer
  • the red spectral range comprises wavelengths between and including 640 nanometer and 780 nanometer
  • the green spectral range comprises wavelengths between and including 490 nanometer and 570 nanometer
  • detector readings corresponding to emissions in the above mentioned spectral ranges are combined in order to determine the blood oxygen saturation, the blood pressure and/or the arterial sti f fness .
  • the sensor module comprises one emitter, two emitters , three emitters or a plurality of emitters .
  • at least two of the emitters emit electromagnetic radiation at the same or at di f ferent wavelengths .
  • all emitters emit electromagnetic radiation at the same or at di f ferent wavelengths .
  • the detector detects electromagnetic radiation emitted by the emitter, the second emitter and the third emitter during operation .
  • the detector is a broadband detector that can detect incident electromagnetic radiation in a spectral range between infrared light and green light .
  • the detector at least partially converts electromagnetic radiation with wavelengths between and including 490 nanometer and 1500 nanometer into the electric voltage or the electric current . It is also possible that the detector at least partially converts electromagnetic radiation with wavelengths between 490 nanometer and 1100 nanometer, inclusive , or between 490 nanometer and 2200 nanometer, inclusive , or between 490 nanometer and 2500 nanometer, inclusive , into the electric voltage or the electric current .
  • the semiconductor layer sequence of the detector comprises or consists of silicon or indium gallium arsenide phosphide , Inx-xGax SyPi-y with 0 ⁇ x ⁇ l and 0 ⁇ y ⁇ l .
  • the emitter, the second emitter and the third emitter emit electromagnetic radiation in a time- multiplexed manner, such that the electromagnetic radiation detected by the detector can be uniquely assigned to the respective emitter .
  • the sensor module comprises a dedicated detector for each emitter .
  • the sensor module further comprises a second detector and a third detector, wherein the detector detects electromagnetic radiation in the infrared spectral range , the second detector detects electromagnetic radiation in the red spectral range and the third detector detects electromagnetic radiation in the green spectral range .
  • the sensor module comprises , one detector, two detectors , three detectors or a plurality of detectors .
  • at least two of the detectors detect electromagnetic radiation in the same or in di f ferent wavelength ranges .
  • all detectors detect electromagnetic radiation in the same or in di f ferent wavelength ranges .
  • each detector detects electromagnetic radiation in a wavelength range that corresponds to the wavelength of the electromagnetic radiation emitted by an associated emitter, respectively .
  • the detector comprises a bandpass filter for filtering the incident electromagnetic radiation .
  • the emitter is a VCSEL and the bandpass filter of the associated detector is matched to a spectral linewidth of the emitter .
  • the bandpass filter is a Bragg filter, i . e . a filter comprising a stack of dielectric layers with alternating refractive indices .
  • the bandpass filter is arranged on the light transmitting surface of the detector .
  • the bandpass filter is configured for tuning the main detection direction of the detector .
  • the main detection direction and/or the directional characteristics of the detector can be adj usted using the bandpass filter .
  • the bandpass filter has an angular characteristic or directional characteristic, wherein a central transmission wavelength of the bandpass filter changes with an angle of incidence of the incident electromagnetic radiation .
  • the bandpass filter of the detector can be adj usted such that the electromagnetic radiation emitted by the associated emitter can only be detected by the detector i f it is incident on the light transmitting surface of the detector under a preferred detection angle and/or a preferred angle of incidence .
  • Figure 1A shows a schematic cross section of a sensor module according to an exemplary embodiment .
  • Figure IB shows a schematic cross section of an arrangement of a sensor module according to an exemplary embodiment on a person' s body part .
  • Figures 2 , 3 and 4 show examples of detector signals of a sensor module according to an exemplary embodiment .
  • Figures 5A, 5B, 6A and 6B show a normali zed perfusion index PI /PIo as function of an emitter angle or a detector angle of a sensor module according to an exemplary embodiment .
  • Figure 7 shows a schematic illustration of light propagation from an emitter to a detector of a sensor module according to an exemplary embodiment .
  • Figures 8 to 14 show schematic cross sections of sensor modules according to further exemplary embodiments .
  • the sensor module 1 according to the exemplary embodiment in Figure 1A comprises an emitter 2 and a detector 4 arranged on a flat main surface 51 of a carrier 5 .
  • the emitter 2 comprises a light emitting diode ( short : LED) or a VCSEL, whereas the detector 4 comprises a photodiode or a phototransistor .
  • the emitter 2 and the detector 4 are arranged laterally adj acent to each other at an edge-to-edge distance d of at most 3 millimeters .
  • the carrier 5 is a printed circuit board with electrical contact pads for electrically contacting the emitter 2 and the detector 4 .
  • the emitter 2 is a packaged LED or a packaged VCSEL
  • the detector is a packaged photodiode or a packaged phototransistor .
  • the package comprises or consists of a base plate , a semiconductor chip mounted on the base plate , a frame mounted on the base plate such that it completely surrounds the semiconductor chip in all directions parallel to the base plate , and an encapsulation disposed on and around the semiconductor chip, respectively .
  • the semiconductor chip is the LED chip, the VCSEL chip, the photodiode chip, or the phototransistor chip, respectively .
  • the emitter 2 consists of the LED chip or the VCSEL chip
  • the detector 4 consists of the photodiode chip or the phototransistor chip.
  • the semiconductor chips of the emitter 2 and/or the detector 4 can be directly mounted on the carrier 5 of the sensor module 1 without using a separately packaged emitter 2 and/or detector 4 .
  • the emitter 2 emits electromagnetic radiation 3 in an infrared, red or green spectral range .
  • the emitter 2 has a directional characteristics 26 with a main emission direction 21 .
  • a power per unit solid angle of the emitted electromagnetic radiation 3 is maximal along the main emission direction 21 .
  • the light emitting diode has a Lambertian directional characteristics
  • the VCSEL has a directional characteristics that deviates from the Lambertian directional characteristics in that it has a strong elliptical distortion with a maj or axis along the main emission direction, for example .
  • the detector 4 has a directional characteristics 46 with a main detection direction 41 .
  • a sensitivity per unit solid angle of the detector 4 for the incident electromagnetic radiation 3 is maximal along the main detection direction 41 .
  • the main detection direction 41 is directed away from the detector 4 instead of towards the detector 4 , i . e . opposite to the propagation direction of the incident electromagnetic radiation 3 .
  • the main emission direction 21 of the emitter 2 forms an emission angle 0 E with the surface normal 52 of the main surface 51 of the carrier 5 , such that it is inclined away from the detector 4 and/or form the main detection direction 41 .
  • the emission angle 0 E is between and including 30 ° and 60 ° .
  • the emitter 2 can be mounted with a tilt with respect to the main surface 51 of the carrier 5 , for example .
  • the main detection direction 41 of the detector 4 forms a detection angle 0 D with the surface normal 52 of the main surface 51 of the carrier 5 , such that it is inclined away from the emitter 2 and/or form the main emission direction 21 .
  • the detection angle 0 D is between and including 30 ° and 60 ° .
  • the detector 4 can be mounted with a tilt with respect to the main surface 51 of the carrier 5 , for example .
  • the main emission direction 21 and the main detection direction 41 lie in a plane that is perpendicular to the main surface 51 of the carrier 5 .
  • the main emission direction 21 has an azimuthal angle of 180 ° and the main detection direction 41 has an azimuthal angle of 0 ° .
  • the emission angle 0 E is non- zero and the detection angle 0 D is zero , or vice versa, as long as an angle between the main emission direction 21 and the main detection direction 41 is non zero , and the main emission direction 21 and the main detection direction 41 do not cross each other in a hal f space 53 above the main surface 51 of the carrier 5 .
  • the angle between the main emission direction 21 and the main detection direction 41 equals 0 E + 0 E and is larger than zero and smaller than 180 ° , or between 40 ° and 140 ° , inclusive , or between 60 ° and 120 ° , inclusive , or between 80 ° and 100 ° , inclusive , or is 90 ° .
  • the main surface 51 of the carrier 5 has a convex shape , such that the main emission direction 21 and the main detection direction 41 are inclined away from each other when the emitter 2 and the detector 4 are mounted on the main surface 51 .
  • the angle between the main emission direction 21 and the main detection direction 41 can be adj usted by changing the distance d between the emitter 2 and the detector 4 , or by changing a curvature of the main surface 51 of the carrier 5 , for example .
  • Figure IB shows a schematic arrangement , where a sensor module 1 according to the exemplary embodiment described in connection with Figure 1A is arranged on a finger 7 of a person .
  • the sensor module 1 is configured as a photoplethysmography sensor for measuring the person' s heart rate , blood oxygen saturation, blood pressure , and/or arterial sti f fness during operation .
  • the sensor module 1 comprises an electrical control circuit 8 for controlling the emitter 2 and the detector 4 .
  • the electrical control circuit 8 is an analog front end and/or an AS IC .
  • the electrical control circuit 8 is arranged externally from the carrier 5 . It is also possible that the electrical control circuit 8 is arranged on the carrier 5 or integrated into the carrier 5 .
  • FIG 2 shows an example of a detector signal 47 as function of time t .
  • the detector signal 47 is an electrical voltage generated by the detector 4 in response to incident electromagnetic radiation 3 emitted by the emitter 2 of the sensor module 1 as described in connection with the exemplary embodiment in Figure 1A.
  • the emitter 2 emits electromagnetic radiation 3 in the green spectral range at a constant intensity .
  • the detector signal 47 is displayed in units of a number of counts C of an analog-digital converter that takes the detector voltage as an input .
  • the sensor module 1 is a photoplethysmography sensor that is attached to the skin of a person .
  • the detector signal 47 exhibits an amplitude modulation due to the person' s heart beat .
  • a characteristic figure of merit of the sensor module 1 is the perfusion index PI that corresponds to a ratio between an AC part of the detector signal 47 and a DC part of the detector signal 47 .
  • the perfusion index PI corresponds to a di f ference of a maximum value max and a minimum value min of the detector signal 47 , divided by an average value of the detector signal .
  • the perfusion index PI is speci fied in percent .
  • the perfusion index PI of the detector signal 47 shown in Figure 2 is approximately 1 , 9% .
  • the perfusion index PI contains the primary information about the heart beat and therefore is of particular importance for photoplethysmography sensors .
  • the sensor module 1 described in connection with Figure 1A advantageously allows to increase the measured perfusion index PI compared to a sensor module 1 where the main emission direction 21 and the main detection direction 41 are parallel . Accordingly, the performance of the sensor module 1 can be increased, the power consumption of the sensor module 1 can be reduced, and/or the sensor module 1 can have a particularly small si ze .
  • Figure 3 shows an example of a detector signal 47 analogous to Figure 2 , but the emitter 2 of the sensor module 1 emits electromagnetic radiation in the red spectral range .
  • the perfusion index PI is approximately 0 , 3% .
  • Figure 4 shows an example of a detector signal 47 analogous to Figures 2 and 3 , but the emitter 2 of the sensor module 1 emits electromagnetic radiation in the infrared spectral range .
  • the perfusion index PI is approximately 0 , 5% .
  • Figures 5A and 5B show a normali zed perfusion index PI /PI 0 of a sensor module 1 according to the exemplary embodiment described in connection with Figure 1A.
  • the normalized perfusion index PI/PI 0 is shown as a function of the detection angle 0 D at a fixed emission angle 0 E of -10° and at a fixed distance d of 3 millimeter between the emitter 2 and the detector 4.
  • the perfusion index PI is plotted relative to a nominal reference value Pio of the perfusion index PI that is measured at an emission angle 0 E of -10° and a detection angle 0 D of -10°.
  • negative emission angles 0 E correspond to main emission directions 21 that are inclined towards the detector 4 and/or towards the main detection direction 41.
  • negative detection angles 0 D correspond to main detection directions 41 that are inclined towards the emitter 2 and/or towards the main emission direction 21.
  • the emitter 2 is a VCSEL and three data sets DS1, DS2 and DS3 of the normalized perfusion index PI/PIo are shown corresponding to three different emitters 2 emitting electromagnetic radiation 3 at wavelengths of 520 nanometer (DS1) , 637 nanometer (DS2) and 940 nanometer (DS3) , respectively .
  • the data in Figure 5A shows that the perfusion index PI is increased for positive detection angles 0 D , i.e. if the main emission direction 21 and the main detection direction 41 are inclined away from each other.
  • the perfusion index PI decreases for negative detection angles 0 D , i.e. if the main detection direction 41 is inclined towards the emitter 2.
  • the enhancement of the perfusion index PI for detection angles 0 D between 35° and 55°, inclusive is about 20% for electromagnetic radiation 3 in the red (DS2) and infrared (DS3) spectral ranges.
  • DS1 electromagnetic radiation 3 in the green spectral range
  • the perfusion index PI is enhanced as well, albeit the enhancement is not as large as for electromagnetic radiation 3 in the red and infrared spectral range.
  • Figures 6A and 6B show the normalized perfusion index PI/PI 0 of a sensor module 1 according to the exemplary embodiment described in connection with Figure 1A.
  • the distance d between the emitter 2 and the detector 4 is 2 millimeters.
  • the data for the perfusion index PI is plotted relative to a nominal reference value Pio-
  • the nominal reference value Pio of the perfusion index PI is taken at an emission angle 0 E of -10° and a detection angle 0 D of -10°.
  • Figure 6A shows data of the normalized perfusion index PI/PI 0 for five different emission angles 0 E between 25° and 65°, inclusive, at a fixed detection angle 0 D of -10°
  • Figure 6B shows data of the normalized perfusion index PI/PI 0 for five different detection angles 0 D between 25° and 65°, inclusive, at a fixed emission angle 0 E of -10°
  • emission angle 0 E Figure 6A
  • detection angle 0 D Figure 6B
  • data is shown for three different wavelengths of the electromagnetic radiation 3, namely 530 nanometer, 637 nanometer and 940 nanometer.
  • the perfusion index PI increases by at least 15%, if the main emission direction 21 and the main detection direction 41 are inclined away from each other, i.e. if 0 E + 0 D > 0, in particular if 55° > 0 E + 0 D > 15°.
  • the detection angle 0 D is between 35° and 65°, inclusive
  • the perfusion index PI for electromagnetic radiation 3 at a wavelength of 940 nanometer increases by at least 50% relative to the nominal reference value Pio of the perfusion index PI.
  • the increase of the perfusion index PI is asymmetric with respect to changing the emission angle 0 E ( Figure 6A) , or the detection angle 0 D ( Figure 6B ) . In particular, this is due to the di f ferent directional characteristics of the emitter 2 and the detector 4 .
  • Figure 7 shows a schematic cross section of a sensor module 1 according to an exemplary embodiment arranged on a person' s skin 7 and schematically illustrates the propagation of electromagnetic radiation 3 from the emitter 2 to the detector 4 inside the skin .
  • the electromagnetic radiation 3 is repeatedly scattered and/or reflected by plasma and/or red blood cells 71 , for example , such that it is at least partially redirected from the emitter 2 to the detector 4 .
  • the sensor module 1 according to the exemplary embodiment in Figure 8 comprises an emitter 2 and a detector 4 arranged on a main surface 51 of a carrier 5 .
  • the carrier 5 is a printed circuit board
  • the emitter 2 is a packaged LED or a packaged VCSEL comprising a light source 24 , such as a LED chip or a VCSEL chip, with a light emission surface 23 that is parallel to the main surface 51 of the carrier 5 .
  • the emitter 2 further comprises a first optical element 22 that is configured to adj ust the main emission direction 21 and the directional characteristics 26 (not shown here , c . f . Fig . 1 ) of the emitter 2 .
  • the first optical element 22 is a convex lens that is arranged of f-centered from the light source 24 .
  • a center of the first optical element 22 and a center of the light emission surface 23 are laterally displaced by an of fset aO .
  • the of fset aO is at most hal f of a diameter of the convex lens 22 and/or hal f of a diameter of the light emission surface 23 .
  • the main emission direction 21 can be adj usted by changing the of fset aO .
  • the detector 4 is a packaged photodiode or a packaged phototransistor comprising a photosensitive element 44 , such as the photodiode chip or the phototransistor chip, with a light transmitting surface 43 that is parallel to the main surface 51 of the carrier 5 .
  • the detector 4 further comprises a second optical element 42 that is configured to adj ust the main detection direction 41 and the directional characteristics 46 (not shown here , c . f . Fig . 1 ) of the detector 4 .
  • the second optical element 42 is a convex lens that is arranged of f-centered from the photosensitive element 44 .
  • a center of the second optical element 42 and a center of the light transmitting surface 43 are laterally displaced by an of fset aO .
  • the of fset aO of the detector 4 can be the same or di f ferent from the of fset aO of the emitter 2 .
  • the of fset aO is at most hal f of a diameter of the convex lens 42 and/or hal f of a diameter of the light transmitting surface 43 .
  • the main detection direction 41 can be adj usted by changing the of fset aO .
  • the sensor module 1 according to the exemplary embodiment in Figure 9 further comprises a barrier 6 that is arranged on the carrier 5 between the emitter 2 and the detector 4 .
  • the barrier 6 comprises an absorptive material for the electromagnetic radiation 3 emitted by the emitter 2 and reduces optical crosstalk between the emitter 2 and the detector 4 , thereby increasing a signal-to-noise ratio of the sensor module 1 .
  • the sensor module 1 according to the exemplary embodiment in Figure 10 comprises an emitter 2 and a detector 4 arranged on a main surface 51 of a carrier 5 .
  • the carrier 5 is a semiconductor substrate , and the emitter 2 and the detector 4 are not packaged . Rather the LED chip or VCSEL chip 24 of the emitter 2 and the photodiode chip or phototransistor chip of the detector 4 are directly arranged on the main surface 51 of the carrier 5 .
  • the sensor module 1 Compared to the sensor module 1 described in connection with Figure 10 , the sensor module 1 according to the exemplary embodiment in Figure 11 comprises Fresnel lenses as first and second optical elements 22 , 42 .
  • the sensor module 1 Compared to the sensor module described in connection with Figure 1A, the sensor module 1 according to the exemplary embodiment in Figure 12 comprises an emitter 2 and a detector 4 that are arranged on the main surface 51 of the carrier 5 in a tilted manner .
  • the light emission surface 23 of the emitter 2 and the light transmitting surface 43 of the detector 4 are not parallel to the main surface 51 of the carrier 5 .
  • the emitter 2 is a LED with a Lambertian directional characteristics 26 and the main emission direction 21 is perpendicular to the light emission surface 23 .
  • the detector 4 also has a Lambertian directional characteristics 46 and the main detection direction 41 is perpendicular to the light emission surface 23 .
  • the sensor module 1 according to the exemplary embodiment in Figure 13 comprises a VCSEL instead of an LED as emitter 2 .
  • the VCSEL emits electromagnetic laser radiation 3 and has a directional characteristics 26 that deviates from a Lambertian characteristics of an LED .
  • the directional characteristics 26 is elliptically distorted with a maj or axis along the main emission direction 21 .
  • the sensor module 1 Compared to the sensor module described in connection with Figure 8 , the sensor module 1 according to the exemplary embodiment in Figure 14 comprises an emitter 2 with a first reflective element 25 instead of a first optical element 22 , and a detector 4 with a second reflective element 45 instead of a second optical element 42 .
  • the first reflective element 25 is arranged on a side of the emitter 2 facing the detector 4
  • the second reflective element 45 is arranged on a side of the detector 4 facing the emitter 2 .
  • the first and second reflective elements 25 , 45 comprise metallic layers that reflect the electromagnetic radiation 3 emitted by the light source 24 .
  • the first reflective element 25 changes the main emission direction 21 of the emitter 2 away from the detector 4
  • the second reflective element 45 changes the main detection direction 41 of the detector 4 away from the emitter 2
  • the first and second reflective elements 25 , 45 reduce optical crosstalk between the emitter 2 and the detector 4 .

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Abstract

L'invention concerne un module de capteur (1), comprenant : - un émetteur (2) qui émet un rayonnement électromagnétique (3) pendant le fonctionnement, et - un détecteur (4) qui détecte un rayonnement électromagnétique (3) émis par l'émetteur (2) pendant le fonctionnement, - l'émetteur (2) et le détecteur (4) étant disposés sur un support (5), et - une direction d'émission principale (21) de l'émetteur (2) et une direction de détection principale (41) du détecteur (4) étant inclinées de manière à s'éloigner l'une de l'autre.
PCT/EP2024/072342 2023-09-14 2024-08-07 Module de capteur Pending WO2025056247A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102023124796.4 2023-09-14
DE102023124796 2023-09-14

Publications (1)

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WO2025056247A1 true WO2025056247A1 (fr) 2025-03-20

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PCT/EP2024/072342 Pending WO2025056247A1 (fr) 2023-09-14 2024-08-07 Module de capteur

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110188025A1 (en) * 2008-06-20 2011-08-04 Osram Opto Semiconductors Gmbh Light Barrier and Method for Detecting Objects
WO2016050486A1 (fr) * 2014-10-02 2016-04-07 Koninklijke Philips N.V. Capteur optique de signes vitaux
EP3199100A1 (fr) * 2014-08-06 2017-08-02 Valencell, Inc. Oreillette avec un module pour capter des informations physiologiques
WO2018020492A1 (fr) * 2016-07-25 2018-02-01 Biobeat Technologies Ltd Procédé et dispositif de mesure optique de propriétés biologiques
US20180103857A1 (en) * 2015-03-23 2018-04-19 Osram Opto Semiconductors Gmbh Sensor for sensing a biometric function
US20220170852A1 (en) * 2020-11-30 2022-06-02 Seiko Epson Corporation Detecting device and measuring device
WO2024156591A1 (fr) * 2023-01-24 2024-08-02 Ams-Osram Ag Capteur de proximité à faible encombrement

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110188025A1 (en) * 2008-06-20 2011-08-04 Osram Opto Semiconductors Gmbh Light Barrier and Method for Detecting Objects
EP3199100A1 (fr) * 2014-08-06 2017-08-02 Valencell, Inc. Oreillette avec un module pour capter des informations physiologiques
WO2016050486A1 (fr) * 2014-10-02 2016-04-07 Koninklijke Philips N.V. Capteur optique de signes vitaux
US20180103857A1 (en) * 2015-03-23 2018-04-19 Osram Opto Semiconductors Gmbh Sensor for sensing a biometric function
WO2018020492A1 (fr) * 2016-07-25 2018-02-01 Biobeat Technologies Ltd Procédé et dispositif de mesure optique de propriétés biologiques
US20220170852A1 (en) * 2020-11-30 2022-06-02 Seiko Epson Corporation Detecting device and measuring device
WO2024156591A1 (fr) * 2023-01-24 2024-08-02 Ams-Osram Ag Capteur de proximité à faible encombrement

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Title
DAVIS MATTHEW S. ET AL: "Aperiodic nanoplasmonic devices for directional colour filtering and sensing", NATURE COMMUNICATIONS, vol. 8, no. 1, 7 November 2017 (2017-11-07), UK, pages 1 - 10, XP093222580, ISSN: 2041-1723, DOI: 10.1038/s41467-017-01268-y *

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