NL1041276B1

NL1041276B1 - Method and device for measuring a health status and physiological parameters of an user at rest and under movement

Info

Publication number: NL1041276B1
Application number: NL1041276A
Authority: NL
Inventors: Stephanus Franciscus Schilthuizen Ir; Ir Paraskevas Dunias Dr
Original assignee: Scint B V; Beta Applied Res
Priority date: 2015-04-16
Filing date: 2015-04-16
Publication date: 2016-12-20
Also published as: NL1041276A

Abstract

Method and device for measuring a health status and physiological parameters of and user at rest and under movement, to be worn on a wrist of a user. The device includes a securing band, at least one light source having a light emitting surface and at least one light receiver having a light receiving surface. The at least one light source and the at least one light receiver are arranged on the securing band of the device such that when worn, the at least one light emitting surface and the at least one light receiving surface substantially abut against the palmar side of the wrist of the user. The device further includes a pressing element projecting towards the side of the securing band facing the wrist such that the light emitting surface and/or the light receiving surface is pressed into the skin of the wrist, a second light source which is used for detection of movement and motion artefacts.

Description

Title: Method and device for measuring a health status and physiological parameters of an user at rest and under movement

TECHNICAL FIELD

The invention relates to a wrist worn device and a method for measuring a health status of a user. The health status may include a general fitness and/or compliance to an exercise schedule and/or specific physiological or health parameters at a desired value or bandwidth.

BACKGROUND

Wrist worn devices for measuring a health status of a user are known in the art. Unfortunately, such devices may be unreliable in measurement of certain physiological parameters in rest positions and certain physiological parameters under limited and more severe movement, and sometimes therefore report a health status that does not correspond to that of the user. These problems can be exacerbated while attempting to measure a health status of a user during exercise and/or before or after exercise and during movements of the skin, body and arms in general. The effect of the exercises, skin and body movements on the measurements is for many known devices today that these are not reliable and are largely influenced by (motion) artefacts and inaccurate measurements.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a more reliable device and method for measuring a health status and physiological parameters of a user at rest, under movement and during exercise and providing more comfortable solutions for carrying the device on the body on the skin for a longer time. Thereto, according to the invention a device for measuring a health status is provided. The device, to be worn on a wrist or forearm of a user, includes, a securing band, at least one light source having a light emitting surface and at one light source and the at least one light receiver are arranged on the securing band of the device such that when worn, the at least one light emitting surface and the at least one light receiving surface substantially abut against the palmar side of the wrist of the user. According to an aspect of the invention, the device further includes a static or adjustable pressing element, projecting towards the side of the securing band facing the wrist or forearm, such that the light emitting surface and/or the light receiving surface is pressed into the skin of the wrist. The light emitting surface and/or the hght receiving surface can e.g. be positioned on the top of the pressing element.

According to another main aspect of the invention the device includes a plurality of hght emitting and Hght receiving surfaces, which can be used to perform measurements of physiological parameters such as heart rate, heart rate variability and heart rate recovery, oxygen saturation (Sp02), respiration rates, C02 values and a separate set or sets of Hght emitting surfaces and receivers with a different wavelength than the ones used for iHuminating of the blood vessels the above mentioned and measurements of parameters, which can be used for the specific detection of motion artefacts and movement. These specific Hght emitters have either a low penetration depth in the skin (400-550 nm) and or a high water absorption rate (1100-1400 nm). The parallel detection of smaU or bigger motion artefacts can be used in algorithms and software processing to detect at all time the heart rate of the wearer of the device under movement from and within the received Hght signals. These Hght emitters and if necessary receivers can be covered with polarizers to filter the Hght emitted and received in such a way and under such angle that specific movement can be detected. Therefore a polarisation filter is placed on the Hght source resulting in a Hght beam polarised in one direction. The Hght reflected on the skin rotates the polarisation direction of the Hght by ninety degrees. By placing a polarisation filter on the optical sensor turned by ninety degrees in reference to the polarisation filter at the Hght source, the sensor is more sensitive to the reflected Hght and less to the scattered Hght through the tissue. This embodiment will enable detection of heart rates under medium and more severe movement of body, arm en device on arm, due to the ability to distinguish in the signals between movement or motion artefacts and heart rate values.

According to another two main objects of the invention the device contains two solutions to limit or omit the influences of circumferential, ambient light. The first solution hereto consists of flexible deformable nontransparent skirt around the light emitting and light receiving surfaces, touching the skin and following the contour of the skin and blocking penetration of all ambient light. The second solution is the use of modulation of light in the system to subtract possible ambient light values from the measurements being made by the light receiving surfaces.

According to another main object of the invention the parallel sensing of heart rate values and high motion artefacts and movement with specific light emitting and light receiving surfaces will make it possible to asses physical exercise, movement and activity, if necessary combined with accelerometer data, GPS data, tri-angulation GSM positioning data and other available means.

According to another main object of the invention the device can contain one or more of the mentioned specific and adjustable solutions for applying pressure on the skin in the area of the light emitting and light receiving surfaces.

The pressing element provides the advantage that the light emitting surface(s) and/or the light receiving surface(s) can be pressed into the skin of the wrist to the desired extent. This allows for better coupling of light into the wrist and/or out of the wrist. Better coupling of light can improve a signal to noise ratio and/or a signal intensity. Also, the pressing element aids in preventing the light emitting surface(s) and/or the fight receiving surface(s) from sliding across the skin and from detaching from the skin during movement, resulting from the skin and device interaction, exercising, sports and all other human activities

The pressing element can be a passive element, such as a solid element or a resilient element, such as a foam element or a spring element or a combination of both, is adjustable and can be a solid or resilient element or a combination of both which slides up and down in a corresponding cylinder, housing or second element in predetermined or limitless variable positions, a clamp or beam lever which is positioned on the right point of the wrist and is exerting more pressure force after fastening of the securing band or via a separate mechanism or combinations of any of the above. Hence, the pressing element requires no power, but still allows for an increased force pressing the light emitting surface(s) and/or the light receiving surface(s) into the skin, either via manual adjustment of the band of the wrist worn device and or the adjustment of the pressing element itself in one or more directions and or help of an additional mechanically operating element. The pressing element can have a domed shape, such as a e.g rounded, pyramidal shape; a hemispherical shape; a semioval shape; a, e.g. rounded, lozenge shape, a square or rectangular shape, or any irregular shape. The pressing force of the pressing element can be adjustable, e.g. by use of a selected one of a set of interchangeable pressing elements, e.g. having different heights, spring constants, etc. The pressing force of the pressing element can also be adjustable by use of a selected one of a set of interchangeable resilient elements in the pressing elements. The pressing force of the pressing element can also be adjustable by mechanical adjustment of the pressing element, e.g. of a height of the pressing element, such as by telescopic action, a movement or adjustment of two corresponding elements in which one of them can translated and or rotated in one or more directions to the other (e.g. a piston system, a screw thread system, a press and click system with a spring, a non-linear sliding system with curved elements, a combination of any of the above etc.), clamp or beam lever pressing system etc. Finally the pressing force of the pressing element can also be adjustable by adjustment of the tightness or looseness band of the wrist-worm device in a more tightened or loosened fashion with a clasp, a screw thread or another type of mechanically adjustable system.

The positioning of the pressing element within the device can be such that, when worn, the pressing element is positioned to be on top of one or both of the main arteries, in the wrist. These locations are free from tendons so that the pressing force is extra effective.

According to an aspect of the invention, the pressing element is, at least partially, interposed between the securing band and the light emitting surface and/or the light receiving surface. The light emitting surface and/or the light receiving surface are mounted on a carrier, and the pressing element can be, at least partially, interposed between the securing band and the carrier or are completely integrated into one part. The pressing element can be included in a tunnel. The tunnel can be part of the securing band. It is also possible that the tunnel is attached to the securing band, preferably on the side facing the skin.

According to an aspect of the invention, the pressing element can be movably interposed between the securing band and the light emitting surface and/or the light receiving surface. The pressing element can also be, at least partially, movably interposed between the securing band and the carrier. The pressing element can be movably interposed between walls of the tunnel, or between a wall of the tunnel and the securing band. The pressing element being movably interposed allows the pressing element to be positioned in a circumferential and/or axial direction of the securing band. Hence, the pressing element can be positioned to an optimum position, e.g. directly over an artery or another position on the wrist. Optionally, the pressing element is shdingly interposed. Thereto, the surface of the pressing element and/or a surface of the securing band, carrier and/or tunnel facing the pressing element can have a low friction to enable easy sliding.

According to an aspect of the invention, the pressing element has a positioning means projecting outside the securing band, when worn, to allow positioning and re-positioning of the pressing element. The positioning means can be a lever extending beyond a side of the securing band, and/or extending radially through the securing band.

According to an aspect of the invention, the securing band includes a stretchable material enabling a tight securing and delivering a force pressing the pressing element into the skin of the wrist. Hence the pressing element projecting towards the skin can effectively pressed into the skin by an elastic force generated by the securing band. The securing band may comprise a stretchable textile and or foam material, which is permeable to water vapour and gasses, allowing ventilation of the skin. Optionally the foam material on the wrist side is covered with a material allowing absorption of moisture. Alternatively, or additionally, a part of the securing band that is positioned against the back of the wrist has a higher stillness and/or lower resilience than the part of the securing band that is positioned against the inner side of the wrist. This may help in providing an effective pressing force on the pressing element.

According to an aspect of the invention, the device further also can include a deformable non-transparent plastic, rubber, polymer or metal element or a combination of these elements, projecting itself towards the side of the securing band facing the wrist or forearm, such that the light emitting surface and/or the light receiving surface are shielded from all sides between skin and the device itself from ambient, surrounding light and are if necessary pressed with this deformable part into the skin of the wrist. This deformable non-transparent element which can deform due to its material properties and or specific shape and will block the surrounding, ambient or environmental light, allows comfortable wearing of the wrist worn device without too high pressures causing discomfort. It completely shields the light emitting and light receiving surfaces from surrounding natural and or artificial light, it provides due to it’s compression and higher friction characteristics a stable interface to the skin, reducing motion and other artefacts and enabling stable heart rate, Sp02 and other physiological signals.

According to an aspect, the device further includes a control unit arranged for determining a health status, such as a physiological parameter, such as heart rate, heart rate variability, heart rate recovery and/or oxygen saturation, C02 saturation, respiration rates from a signal representative of an amount of light received by the light receiver.

When measuring e.g. the oxygen saturation, the so called Sp02 value, it is preferred to minimise the optical path lengths for irradiating the wrist and for detecting the radiation from the wrist. Minimising such path lengths helps minimise the effect of movement artefacts on the determination of the oxygen saturation. Preferably, (only) light emitting surfaces and light receiving surfaces that are in close proximity to one another are used for determining the oxygen saturation, e.g. neighbouring light emitting surfaces and light receiving surfaces. When multiple light emitting surfaces and multiple light receiving surfaces are used in the device, it may be preferred to not activate all light emitting surfaces at the same time, but to activate the light emitting surfaces in groups or one at a time, so as to minimise the effect of light receiving surfaces receiving light emitted by far away light emitting surfaces.

Another method to achieve this controlled optical path is to manually or mechanically block the light emitters, which are not in the proximity of the light receiving surface intended for the oxygen saturation determination, e.g. via use of a tunnel shaped element in the band which can cover part of the light emitting surfaces or via use of separate slab of material which can be folded over the light emitting surfaces which have to be covered, or via another mechanism such as a turaable unit which has one or more openings for the light emitting and light receiving surfaces which can be turned manually, semi-automatically or automatically.

According to an aspect, the light sources are Light Emitting Diodes, LEDs, and the light receivers are Photodiodes, PDs. The LEDs and PDs can be mounted on the carrier, wherein the carrier can be a flexprint. Optionally, the carrier can be bent with the LED’s and/or PDs on the convex side. Such bent carrier can be included in a cylindrical or dome shaped plastic enclosure. Such enclosure can e.g. be moulded with the carrier included in the mould. Such plastic enclosure can also partly or wholly be compressible, enabling and allowing a static pressing force on the skin with high comfort for the user.

It is possible that the PDs are positioned on a semi cylindrical or dome shaped surface and that the LEDs are positioned on the same position or lower than the PDs, e.g. moulded inside the semi cylindrical or dome shaped part.

According to an aspect, the light emitting surface(s) and the light receiving surface(s) is(are) separated by a non-transparent light blocker. Each light emitting surface may be circumscribed by a light blocker, each light receiving surface may be circumscribed by a light blocker. The light blocker may e.g. be a black or grey plastic material. This helps in preventing direct radiation from a light emitting surface entering a light receiving surface, without travelling through the skin of the user first.

According to an aspect, the fight emitting surface(s) and the fight receiving surface(s) is(are) received in one or more elastic frames, preferably of fight blocking material.

According to an aspect, the fight emitting surface(s) and the fight receiving surface(s) is(are) separated by a deformable non-transparent fight blocker. Each fight emitting surface may be circumscribed by a deformable fight blocking element made from a compressible material, each fight receiving surface may be circumscribed by a fight blocking element made from a compressible material. The fight blocker may e.g. be a black or grey plastic material. This helps in preventing direct radiation from a light emitting surface entering a light receiving surface, without travelling through the skin of the user first. The compressible light blocking material will allow an appropriate pressing force on the skin, which is not too high to cause discomfort and is still high enough to enable a good signal without interference of ambient, circumferential, surrounding light, which can be blocked extra and initially by the partly compressed light blocker touching the skin around the area where light is being emitted in the skin and reflected light is being collected and measured by the fight receiving surface or sensor.

According to an aspect, the fight emitting surface(s) and the fight receiving surface(s) can be covered by a transparent or semi-transparent or slightly coloured cover enabling fight to be emitted and received. These transparent covers can be separated from each other by non-transparent light blocking materials, and are all arranged on a domed or cylindrical shape to enable sufficient fight coupling in the skin of the wrist of the user. This dome can be made of a partly compressible and partly more ridged material or of a compressible material solely.

According to another aspect of the invention a method of eliminating the influences of the environmental, surrounding or ambient fight in the measurements is realized using a modulation scheme. The fight emitting sources are alternately driven in a maximal and minimal fight intensity. A fight source i.e. LED, is driven by a current (or voltage) source, and the fight of the illuminated tissue is measured by a fight receiving surface, the sensor i.e. photodiode or PD as mentioned before. The induced current of the sensor is amplified and digitized using an Analog to Digital Convertor (ADC) in the hardware of the wrist worn device.

The fight source is driven to a maximal or a certain high intensity resulting in a maximal or a certain high ADC output. The fight emitting source (LED) is driven to a minimal or a certain low intensity resulting in a minimal or a certain low ADC output. Those two readings are subtracted from each other in the firmware or embedded software resulting in the final measurement reading. In this way the environmental light which is present as well in the high intensity as in the low intensity measurement is being eliminated. The alternating driving electrical current for the light emitting sources is in this method a square block signal with a certain offset and amplitude. The maximal and minimal value of the current is automatically calibrating before starting a measurement. A light source electrical current position or stand is adjusted in such a way that if the sensor reading exceeds for instance 10% of the ADC range, that electrical current stand is then used as the minimal value of the light source current. A light source electrical current stand is then adjusted in such a way that if the sensor reading exceeds for instance 90% of the ADC range, that electrical current stand is then used as the maximal value of the light source current. A comparable modulation-demodulation scheme can be employed with a light source driven by a periodic electrical current signal like a sinusoidal signal. The demodulation scheme at the sensor side can then be realized by a simple multiplication of the measured signal by the same sinus signal used for the modulation followed by a low pass filtering. The maximal value of the sinusoidal current signal to the light source has to be adjusted to induce a maximal reading at the sensor side, and the minimal value of the sinusoidal current signal to the fight source has to be adjusted to induce a minimal reading at the sensor side.

According to an aspect, the device further includes a wireless communication unit arranged for communicating with a communications device, such as smart phone with a display or a smart watch with a display.

According to an aspect, the securing band is provided with woven, knitted and/or embroidered electrical connection threads connecting the at least one light source and at least one light receiver with the control unit.

According to an aspect, the securing band is provided with at least one light source and at least one light receiver directly connected to the control unit on the same side of the band.

According to an aspect, the securing band is provided with at least one light source and at least one light receiver on the inner side of the wrist connected via wiring or a conductive flexfoil to the control unit which is on another point on the wrist or e.g. on the opposite, upper side of the wrist.

According to an aspect, the at least one light source includes an optical fiber for guiding light towards the skin of the user and/or wherein the at least one light receiver includes an optical fiber for guiding light from the skin of the user. The optical fiber can be woven in, knitted in and/or embroidered on the securing band. At least a section of the optical fiber positioned to mechanically touch the skin of the user has optionally been treated to allow light to couple out and/or in.

According to an aspect, the processing unit is arranged to detect whether the device is properly worn at the wrist on the basis of the quality of the received light signal, the received ambient fight or combinations of both.

According to an aspect, the device further includes an accelerometer arranged for detecting the amount of movement of the wrist of the user.

According to an aspect, the processing unit is arranged for determining the blood composition of the user (hemoglobine, hematocrite, albumin value) for medical purposes such as blood deficiencies after chemo treatment and/or radiation therapy, blood loss after birth or accidents, infections with tropical diseases such as Denque, dehydration etc.

The invention also relates to a method for measuring a health status of a user is provided comprising the steps of: providing a device worn on an arm, e.g. a wrist, of the user, wherein the device includes, a securing band or strap, at least one light source having a light emitting surface and at least one light receiver having a light receiving surface. The at least one light source and the at least one light receiver are arranged on the securing band of the device such that when worn, the at least one light emitting surface and the at least one light receiving surface substantially abut against the palmar side of the wrist of the user, e.g. on top of one or both of the main arteries (radial and ulnar artery) within the wrist, or on a higher position on the underarm or upper arm or on the upper side of the wrist. The method can include performing a measurement session including; emitting light in a wavelength range by the at least one light source for a predetermined amount of time; producing a received light signal by the at least one light receiver corresponding to a received intensity of light received at the at least one light receiver; defining an amplitude of the received light signal (pulsating due to the blood pulsation) to be maximised by using a static force pressing the at least one light emitting surface and/or at least one light receiving surface in a direction substantially perpendicular to the palmar side of the user's wrist, e.g. positioned on top of at least one of main arteries, being the ulnar and radial arteries. This static force pressing is achieved via the application of a raised part or a part which can enlarge the static force pressing at the light emitting and light receiving surfaces via a rotation and or translation in the direction of the wrist, to the centre of the wrist or directed at the arteries in the wrist. This rotational and or translational movement of this raised part can be in predefined steps via a screw-thread, bayonet closure, or a press lock system or can be continuous without predetermined pressing positions resulting in customized positions.

The raised part can optionally be a deformable part, such as a deformable foam and/or plastic part, or an element with at least one raised area. The raised part can optionally be a deformable spring combined with a non-deformable or a deformable part or both, such as a deformable foam and/or plastic part, or an element with at least one raised area. This raised area on the deformable element will ensure that the light emitting and light receiving surface will be pressed into the skin directly on top of one or both of the main arteries in the wrist (ulnar or radial artery). These areas of the wrist are deformable and not rigid due to absence of tendons in these areas, and can be compressed with the raised area(s). The light emitting and receiving surfaces are positioned on top of the areas where most light reflection of the arteries can be expected. In this way the radiative flux into the palmar side of the wrist and/or the radiative flux out of the palmar side of the wrist is controlled in a static way. The position of the static pressing element can be varied in the securing band in the longitudinal and circumferential direction of the arm/wrist to adjust the measurement position to the personal physical dimensions of the arm and/or wrist and also if necessary in the radial direction towards the centre of the wrist from the inner side or the upper side of the wrist or directed toward the arteries to achieve a better signal. The adjustment of the static force pressing element in the band can be automatically, in a self seeking manner, as explained below, or can be done via manual adjustment and shifting in one or two or three directions by the user himself. When the user puts on the band a first heart rate measurement can be being carried out via the light emitting and light receiving surfaces. The results of the measurement, e.g. the physiological heart rate or other vital signs signal, can be visualized at a screen on the band, on a separate smartphone app, or via an audio and or light signal. Optionally, an indication is presented to the user to instruct the user to adjust the position and or shape of the static pressing element in a certain direction or to(wards) a certain position, so as to achieve a better signal, e.g. higher amplitude or better signal to noise ratio, for the next measurements. Optionally the device itself adjusts the vertical position of the static pressing force system, radially oriented at the centre of the wrist or directed towards the arteries.

Optionally, the wrist worn device includes one or more light sources and light receivers which can be pressed on the slrin more tightly or loosely via a passive spring system which is tightened, compressed or loosened when the band is fastened to the skin. This system can be made into a controllable actuator when it’s coupled to a mechanism, which tightens the band more or less based upon received light and possibly other sensor signals. The improving of the signal can also be achieved via the use of a static force pressing mechanism which has an adjustable pressing force in a direction perpendicular to the centre of the wrist, e.g. via a screw thread or piston system or an inflatable air balloon system pressing on the light emitter and light receiver. The improving of the signal can also be achieved via a clamp beam or beam lever system which presses the light sources, the light sensor packed in the polymer or non-polymer materials more or less into the skin.

The improvement of the signal can also be achieved via the use of at least two sets of light emitting surfaces and light receiving surfaces, one set positioned and pressed into the skin area directly on top of the radial artery on the thumb side and one set near the ulnar artery on the little finger side.

The improvement of the signal can also be achieved via the use of at least two sets of light emitting surfaces and light receiving surfaces, one set positioned and pressed into the skin area directly on top of the radial artery and or ulnar artery and one set on the upper side of the wrist.

The improvement of the signal can also be achieved via the use of at least one set of light emitting surfaces and light receiving surfaces, positioned on the upper side of the wrist and which can be pressed with a larger or smaller force into the skin.

The improving of the signal can also be achieved via the use of a static force pressing mechanism which is adjustable in force perpendicular to the centre of the wrist, automatically in a self seeking manner, when the user puts on the strap or band with the light emitting and light receiving elements on his arm, more specifically on the inner side of his wrist. A static pressing element, which is fitted in the strap/band, can be arranged to be able to slide along the inner circumference of the band/strap during fastening. The element can be equipped with at least one raised area containing the at least one light emitter and fight receiver, which will be pushed into the tendonless area of the skin on the left side or right side of the inner wrist area, almost directly on top of one of the two main arteries. The heart rate, oxygen saturation and/or other biometric or physiologic parameters can thus be measured. The static pressing on the light emitting and fight receiving surfaces of the measurement system will ensure that the transport of fight into the skin and arm is enhanced as well as the reception of the non-absorbed, reflected fight by the fight receiving surface. Secondly, the fight emitting and fight-receiving surfaces will by this also be closer positioned to the radial and/or ulnar artery or the centre of the wrist, without interference from tendons, ligaments and wrist-bones.

The improving of the signal can also be achieved via the use of at least two sets of fight emitting and fight receiving surfaces, one positioned and pressed into the skin area directly on top of the radial artery on the thumb side and one near the ulnar artery on the little finger side.

The improving of the signal can also be achieved via the use of at least two or three sets of fight emitting surfaces and light receiving surfaces, one set positioned and pressed into the skin area directly on top of the radial artery and or ulnar artery and one set on the upper side of the wrist where also smaller blood vessels are present and can be measured with light emitting and fight reflection measurement techniques as described before.

The improving of the signal can also be achieved via the use of at least four or more sets of light emitting and fight receiving surfaces, two or more sets being positioned and pressed into the skin area directly on top of the radial artery on the thumb side and two or more sets near the ulnar artery on the little finger side.

The improving of the signal can also be achieved via the use of a set with at least three or more light emitting surfaces per light receiving surface/sensor, positioned and pressed into the skin area directly on top of the radial artery on the thumb side and the ulnar artery on the little finger side.

The improving of the signal can also be achieved via the use of a set with at least two or three or more light emitting surfaces per light receiving surface/sensor, positioned and pressed into the skin area directly on top of the radial artery on the thumb side and the ulnar artery on the little finger side, integrated in a plastic moulded part together with the light receiving surface(s). The moulded part can be spherically or cylindrical shaped on the skin side, realizing here the previously mentioned raised area. The moulded part can have a flatter and flange shaped contour on the side facing the band, to allow easy sliding and repositioning in the band to achieve a better measurement signal.

The improving of the signal can also be achieved via the use of the compressible light blocking shielding around the set or sets of light emitting and light receiving surfaces.

The improving of the signal can also be achieved via the use of modulation scheme for the LEDs and PDs as described on the end of page 9 and on the first half of page 10.

Additionally, it will be appreciated that a health status can include a general fitness, heart rate measurement and derivates thereof such as heart rate variability value which is directly related to levels of stress, heart rate recovery rate value which is related to a general fitness or physical health condition, the oxygen saturation rate within the blood which can be measured by using two light sources with different wavelengths, the respiration rate on basis of the periodic fluctuation of the heart rate signal, the C02 saturation rate in veins, arteries and in other blood vessels which is a valuable factor for premature bom babies to determine the function and quality of the respiratory system and for other applications such as acidification of muscles during sports exercises, the blood pressure and/or a compliance to an exercise schedule of a user.

Optionally, the improving of the signal includes the increasing and or decreasing of the force manually via adjustment of the position and/or shape of the static pressing element or via a manual or automatic adjustment of the force pressing on the light emitting and light receiving surfaces, to achieve an optimum in the amplitude of the pulsating signal. It has been found that when the pressure increases, from zero, between skin and the light emitting and light receiving surfaces, that the amplitude of the received light signal, the radiative flux out of the palmar side of the wrist, increases up to a certain maximum of the amplitude, and then starts decreasing again. The optimum of the pressure level can be found by increasing and decreasing the force pressing on the at least one light emitting surface and/or the at least one light receiving surface. Also has been found that the effect from the ambient or surrounding light can be eliminated when the pressure increases. To guarantee the comfort of the user this pressure force can be limited via the application of a compressible and deformable light blocking shield around the light emitter and receivers and via the use of a compressible light blocking and light emitting casing directly around the LEDs and PDs, which can move also towards or away from the arteries or centre of the wrist via a spring mechanism, a piston mechanism, a clamp or beam lever mechanism or combinations of any of the above. The modulation system for the light emitters and light receivers will also limit the influence of the environmental, ambient surrounding day and or artificial light. The amount of pressing, the tightness of the contact of the light emitting and receiving unit on the skin, the comfort and the desired quality of the signal can so be brought into balance to achieve an optimal product.

Optionally, the method further includes controlling the amplitude of the received light signal to maximise the amplitude of the pulsating component of the fight signal by controlling an emitted intensity of fight emitted by the at least one light source. It is conceivable that in order to better control the amplitude of the received light signal, that in addition to the static pressing force, the emitted intensity of light emitted by the at least one light source is controlled. The emitted intensity of light emitted by the at least one light source can be measured as radiant emittance or radiant excitance measured as power per unit area radiated by a surface.

Optionally, the method includes determining the amplitude of the pulsating light signal by measuring the received light signal during a predetermined period, and determining the amplitude value on the basis of the measured received light signal during the predetermined period.

Optionally, the step of determining the amplitude of the pulsating signal is performed at the start of the measurement session. In this way the amplitude of the pulsating signal corresponds to the conditions present at the beginning of the measurement session.

Optionally the method further includes determining whether the controlling mechanism should be manually adjusted based upon the received light signal, based upon the amplitude of the received light signal more in particular, and based upon one or more received additional sensor signals (pressure sensor, accelerometer sensors, additional light signals from a different wavelength received by the light receiver etc.) or based on a received light signal from an addition light source with a wavelength which is different from the wavelength or wavelengths which is or which are being used to measure the desired physiological parameters. This extra wavelength is also not able to penetrate the skin deeply and or has a high water absorption and which will more clearly show movement of the light source and the light receiver on the skin (e.g. blue and/or green LED-light, e.g. a wavelength with a high water absorption capacity of e.g. 1100-1400 nm and the corresponding sensors), measures the motion artefacts and the influence of circumferential light. The blue or green LED-lights or light emitters with a wavelength between 400 and 550 nm, or any other light emitter and receiver such as a 1100 nm system or with a higher wavelength till 1400 nm is primarily being used for the detection of movement and motion artefacts, but can if necessary also be used to perform additional heart rate or pulsation measurement in smaller blood vessels (capillaries, arterioles) directly under the skin on the upper side, inner side of left or right side of the wrist, This also applies to light emitters of other wavelengths.

Another embodiment or facility, increasing the sensitivity to the movement of the wearable device in reference to the skin, is formed by using appropriate polarisation filters at the light source(s) and the optical sensor(s). The movement sensor consisting of a light source and an optical sensor is preferable measuring only the movement of the wearable device in reference to the skin, via the reflection of light. Therefore the movement sensor has to be predominantly sensitive to the reflection of the light on the skin and less sensitive to the scattering of light through the tissue. The light scattered through the tissue shows a pulsating element related to the pulsing of blood. This pulsating element has to be minimised in the movement sensor reading to separate the movement from the blood pulsating in the analysis of the measurements in an algorithm and software. Therefore a polarisation filter is placed on the light source resulting in a light beam polarised in one direction. The light reflected on the skin rotates the polarisation direction of the light by ninety degrees. By placing a polarisation filter on the optical sensor turned by ninety degrees in reference to the polarisation filter at the light source, the sensor is more sensitive to the reflected fight and less to the scattered fight through the tissue. This embodiment will enable detection of heart rates under medium and more severe movement of body, arm en device on arm, due to the ability to distinguish in the signals between movement or motion artefacts and heart rate values.

Optionally, the method further includes determining the amount of manual adjustment of position and shape and or adjustment of pressing force of the static control mechanism based upon the received light signal, based upon the received light signal and one or more additional sensor signals (pressure sensor, accelerometer sensors, additional light signals from a different wavelength received by the light receiver etc.), or based on a received light signal from an addition light source with a wavelength which is not able to penetrate the skin deeply and which will show more clearly movement of light source and light receiver on the skin (e.g. a blue and/or green LED-light of 400-550 nm or a 1100-1400 nm LED light).

Optionally, the method further includes a separate set of light emitter and light receiving surfaces on the outside of the band of the wrist worn device, on which the user can place one of it’s finger to perform a separate measurement of heart rate and oxygen saturation in a defined tissue volume with a known and limited optical path. This additional measurement method with the same device requires a separate action of the user but can be applied to validate, compare and or calibrate the heart rate and/or oxygen saturation measurements which have been determined with the light emitting and receiving surfaces on the inside of the wrist. The user can get an instruction to perform this separate measurement via the display of the wrist worn device and/or the smart phone with application software.

Optionally, the method further includes determining the user’s heart rate and/or related health parameters such as heart rate variability (is a measure for stress) and heart rate recovery (an indication of physical condition) and oxygen saturation on the basis of the received fight signal based on time and/or frequency domain analysis. The high frequency component of the received fight signal may also be used.

Optionally, the method further includes performing a first measurement session wherein the fight emitted by the at least one fight source is in a first wavelength range and performing a second measurement session wherein the light emitted by the at least one light source is in a second wavelength range. Using light in a first wavelength range followed by light in a second wavelength range allows for additional health indicators to be determined and to determine the heart rate parameter via two measurements. The amount of different wavelengths to be used can be one, two, three or more depending on the desired accuracy, artefact compensation measures, redundancy and additional health indicators to be measured.

Optionally, the step of performing a measurement session further includes a step of calculating a perfusion index value on the basis of the received light signals of two light sources or two light wavelengths of e.g. 600-660 nm and 880-940 nm. Optionally, the method further includes determining the user’s saturation of peripheral oxygen level, Sp02, on the basis of a ratio of the perfusion index value calculated in the first measurement session and the perfusion index value calculated in the second measurement session, and optionally on the basis of a value of a control signal of the control unit for controlling the force and/or emitted intensity. Here the oxygen saturation of the user’s blood and changes in the blood volume in the skin are monitored.

The changing absorbance at each of the wavelengths is measured allowing the absorbance due to the pulsing of the blood to be determined. The wrist worn device can act as a plethysmograph, and a photoplethysmogram may be produced and displayed.

The perfusion index valve can be calculated on the basis of a ratio of a high frequency component and a low frequency component of the received light signals.

Optionally, the at least one fight source includes a plurality of fight sources and at least one fight receiver includes a plurality of fight receivers, arranged around the circumference of the arm, e.g. wrist, or around part of the circumference of the arm, e.g. wrist, perpendicular to the arm or parallel to the arm or in both or more directions.

Providing a plurality of light sources and a plurality of light receivers allows for different possibilities of emitting hght. Furthermore, with a plurality of receivers the received hght signal can be produced in different ways.

Optionally, the step of producing the received hght signal at the at least one hght receiver includes averaging the received hght signals produced at a subset of the plurality of hght receivers. Through averaging a more rehable received hght signal can be produced.

Optionally, the step of producing the received hght signal at the at least one hght receiver includes selecting an optimum received hght signal produced at one of the hght receivers. In this way a received hght signal is produced at more than one of the hght receivers, and the optimum received hght signal is selected. Optionally, the optimum received hght signal is selected on the basis of an alternating signal (AC) to static signal (DC) ratio, determining the best AC/DC ratio to be able to distinguish the heart rate as first primary parameter for health measurement and derivatives thereof (Heart Rate Variability and Heart Rate Recovery) and e.g. using the received AC/DC signal to determine oxygen saturation, dehydration or other parameters.

Optionally, the step of producing the received hght signal at the at least one hght receiver includes selecting the best and second best received signal produced at two of the hght receivers. Additionally, the best and second best received signal may be combined for example by averaging.

Optionally, the method further includes detecting a movement of the user, and or the presence of skin against the measurement device on the basis of the received hght signals, which can be the hght signals being used to measure physiological parameters or other hght signals which penetrate not so deeply in the skin. Detecting a movement of the user and/or presence of skin against the measurement device can be used to determine the amount or level of artefacts influencing the received signal, can be used to determine if a user is following a prescribed exercise regime, and/or if a user is moving enough to achieve a given health status. Optionally the method further includes detection of the effect or presence of surrounding artificial or natural light via the received light signals, so that the user can tighten the system more or less.

Optionally, the method further comprises a step of selecting the at least one light source from the plurality of light sources and selecting the at least one fight receiver from the plurality of fight receivers, wherein the step of selecting comprises; for each fight source of the plurality of fight sources emitting light in a wavelength range for a predetermined amount of time; producing at each fight receiver a received fight signal corresponding to the fight received at that fight receiver individually from each fight source; separating each received fight signal into a high frequency component and a low frequency component; calculating for each received fight signal a perfusion index value on the basis of a ratio of the high frequency component and the low frequency component, and selecting a fight source and fight receiver combination having the highest perfusion index value as the at least one fight source and the at least one fight receiver.

It has been shown that selecting the light source and light receiver combination having the highest perfusion index (or AC/DC ratio) value provides an improved received fight signal. Different filtering possibilities exist for separating each received fight signal into a high frequency component and a low frequency component. The cut-off values frequencies may be based on the lowest expected heart rate and/or the highest expected heart rate.

Optionally, the method includes selecting a subset of fight sources of the plurality of fight sources and a subset of fight receivers of the plurality of fight receivers having the highest perfusion index values as the at least one fight source and the at least one fight receiver. In this way methods of producing the received fight signal on the basis of more than one fight source and fight receiver combination can also be performed.

Optionally, the step of selecting is performed for a first wavelength range and a second wavelength range and optionally a third and optionally fourth wavelength range. It is conceivable that different light source and light receiver combinations are ideal for the first wavelength range and the second wavelength range. It can be advantageous to determine the light source and light receiver combination independently.

Optionally and preferably, (only) light emitting surfaces and light receiving surfaces that are in close proximity to one another are used for determining the oxygen saturation, e.g. neighbouring light emitting surfaces and light receiving surfaces. When multiple light emitting surfaces and multiple light receiving surfaces are used in the device, it may be preferred to not activate all fight emitting surfaces at the same time, but to activate the fight emitting surfaces in groups around in dose proximity to a fight receiving surface or one at a time, to limit and diminish the optical path and illuminated tissue volume, and by this to minimise the effect of fight receiving surfaces receiving fight emitted by far away fight emitting surfaces. This will enhance the accuracy and reproducibility of the oxygen saturation measurement.

Optionally, the method further comprises a way of determining the amount of physical movement or exercise of the user by a combined use and analysis of heart rate values and the detected movement via the fight reflection measurement with the additional fight emitter and receiver of a different wavelength such as 400-550 nm or 1100-1400 nm, so that only a higher heart rate combined with a higher motion artefact detection indicates physical exercise. The analysis of these two measurement can be combined with data of an integrated 3-axis accelerometers in the device, a GPS receiver in the device or in a wirelessly connected communication device (smart watch, smart phone, navigation device etc.), a tri-angulation GSM positioning method in the device itself or in the wirelessly connected device, an electrical or optical temperature sensor measuring the increasing temperature of the skin dining exercise.

Optionally, the method further comprises a step of displaying on a display associated with the wrist worn device an instruction instructing and advising the user to perform a predetermined exercise; performing a measurement session while the user performs the predetermined exercise; and storing a result of the measurement session, wherein the result preferably includes the user’s heart rate and/or saturation of peripheral oxygen level and/or ability to recover the user’s heart rate at a normal, non-exercising level, for example heart rate recovery.

In this way, an indication of the user’s health can be determined while performing a predetermined exercise. The display may be included in or on the wrist worn device. Additionally, or alternatively, the display may be included in an external device, such as a smart phone device, that is communicatively connected with the wrist worn device, wired or wirelessly.

Optionally, the method further comprises, measuring the general fitness of the user on the basis of the measurement session and/or previous measurement sessions; displaying an indication of the general fitness and/or health of the user. In this way, the user and/or a health advisor can quickly determine an indication of the user’s general fitness.

Preferably a graphical representation of a person having a general fitness corresponding to the general fitness of the user is displayed. For example if it is determined that the general fitness of the user is poor, the displayed graphical representation of the person may have his hands on his knees and he breathes heavily. On the other hand if the general fitness of the user is good, the displayed graphical representation of the person may be performing jumping jacks, or be jogging in place. Or, on the other hand if the oxygen saturation value and or heart rate recovery rate of the user is good, the displayed graphical presentation of the person may be moving faster than if the oxygen saturation value and or heart rate recovery rate of the user is less good, giving an indication of a lower general fitness or deteriorating health condition resulting in a slower movement of the graphical presentation of the person.

Optionally, the graphical representation moves and is coloured corresponding to the general fitness of the user and/or compliance to the exercise schedule and/or measurement of movement with higher heart rate values. For example, if the general fitness of the user and exercise compliance is determined to be poor, the displayed graphical representation may be coloured orange to red and or moving slowly in the display. Similarly, if the general fitness of the user and/or exercise compliance is determined to be improving, the displayed graphical representation may be coloured orange green and/or moving a bit faster in the display than the displayed graphical presentation in red, representing a status of low exercise compliance, low oxygen saturation values or not improving heart rate parameters.

Similarly, if the general fitness of the user and/or exercise compliance is determined to be good, the displayed graphical representation may be coloured green and or moving even faster in the display.

Optionally, the graphical representation moves and or is coloured and shaped corresponding to the Body Mass Index of the user and/or his/her compliance to the exercise schedule.

Optionally, the wrist worn device further including a wireless communication unit arranged for communicating with a communications device, such as a smart phone, with display. In this way, the wrist worn device can take advantage of the smart phone’s processing power, display capabilities, and user interface, e.g. via combined use with a smart phone application (app).

Optionally, the securing band is provided with woven, knitted and/or embroidered electrical connection threads connecting the at least one light source and at least one light receiver with the control unit. Retaining the electrical connection threads in the securing band allows the control unit to be placed remotely from the at least one light emitting surface and at least one light receiving surface and can be adjusted more easily to the dimensions and different wrist circumferences of various users. This is advantageous as the at least one light receiving surface substantially abut against the palmar side of the wrist of a user.

Optionally, the at least one light source includes an optical fiber for guiding light towards the skin of the user and/or wherein the at least one light receiver includes an optical fiber for guiding light from the skin of the user. Advantageously, the at least one light source and/or the at least one light receiver may be remote from the skin of the user on palmar side of the wrist.

Optionally, the optical fiber is woven in, knitted in and/or embroidered on the securing band. Optionally, the optical fiber is included in the securing band such that the ends of the fibers are mechanically touching the skin of the user. In this way the band holds the end of the fibers in position for guiding light towards and/or away from the skin of the user.

Optionally, at least a section of the optical is fiber positioned to mechanically touch the skin of the user has been treated mechanically or chemically to allow light to couple out and/or in.

Optionally, the wrist worn device includes a plurality of static force pressing elements and a plurality of light sources having a plurality of light emitting surfaces and a plurality of light receivers having a plurality of fight receiving surfaces wherein each static force pressing element is arranged for exerting a force on one fight emitting surface and/or one fight receiving surface pushing these surfaces more on and/or into the skin of wrist preferably positioned in the areas of the skin on top or above the position of the radial and or ulnar artery.

Optionally, the light emitting surface of the at least one fight source and/or the light receiving surface of the at least one fight receiver is covered with a transparent soft polymer cover, preferably spherically shaped or thicker and protruding above the fight emitter and receiver surfaces and surrounded with an elastic frame, of light blocking non transparent polymer material, separating the light emitting surfaces from the light receiving surfaces.

In this way the light emitted from the light emitting surface is directed substantially towards the skin of the user. Stray light emitted from the light emitting surface is prevented from interfering with other emitting surfaces and from entering the light receiving surface without traveling through the user. Therefore, crosstalk between light sources and light receivers is reduced substantially. Also ambient light can be blocked by this method, combined with the mechanical force applied by the fastened securing band and the static force pressing element integrated or being part of the securing band.

Optionally, the cover is cylindrical or spherically shaped and is arranged to be pressed inwardly of the palmar part of the wrist by adjusting the securing band and/or the static force pressing element, preferably on top of the radial and or ulnar artery. A spherically or cylindrically shaped cover improves the coupling of light emitted from the light emitting surface into the user, and improves the capture of light traveling out of the user and into the light receiving surface.

Optionally, the processing unit is arranged to detect whether the device is properly worn, or even worn at all, at the wrist on the basis of the received light signal. When the device is worn properly, an expected received light signal can be determined. On the basis of this signal, it can be determined if the received light signal corresponds to a properly worn device.

Optionally, the wrist worn device further includes an accelerometer arranged for detecting the amount of movement of the wrist of the user and or the device on the wrist of the user and gives an indication of physical activity of the body of the user. This may provide an indication of the amount of everyday movement of the user. Additionally, or alternatively, this may provide an indication of a user’s compliance to an exercise program or schedule. Furthermore, the output signal of the accelerometer may be provided to the processing unit and/or the control unit for taking the amount of movement of the wrist of the user into account when determining the amplitude envelope control band and/or controlling the force.

Optionally, the processing unit is arranged for determining the blood composition of the user (haemoglobin, haematocrit, water, plasma value) for medical purposes such as blood deficiencies after chemo treatment and/or radiation therapy, blood losses after birth or accidents, infections with tropical diseases such as Denque.

Further, according to the invention a system including a wrist worn device according to the invention including a communication unit for wired or wireless communication and a communications device such as a display on the wrist worn device and or a smart phone with a display.

It will be appreciated that features described with regard to one of the method according to the invention, the device according to the invention and the system according to the invention are considered to be disclosed for the remaining categories.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further elucidated by means of non-limiting examples referring to the drawings, in which

Fig. 1 shows a schematic top view of a wrist worn device according to the invention;

Figs. 2a, 2b, and 2c show a schematic side view of a part of a wrist worn device according to the invention with an exemplary static force pressing element;

Fig. 2d shows an example of a tunnel shaped element on the inside of the securing band.

Fig. 3 shows a schematic representation of a system according to the invention including a wrist worn device and a communications device;

Fig. 4 shows the system according to the invention displaying an indication of the general fitness and/or health of a user; and

Fig. 5 shows the system according to the invention displaying an indication of the general fitness and/or health of a user;

Fig. 6 shows an alternative shape and mounting method for a static force pressing element with moulded spring parts.

Fig. 7 shows an alternative version of the static force pressing system with a piston system.

Fig. 8 shows a clamp and beam lever system.

Fig. 9 shows a compressible shield around the light emitting and fight receivers which blocks ambient fight and allows a high comfort during wearing.

DETAILED DESCRIPTION

Fig. 1 shows a schematic top view of a wrist worn device 1 according to the invention, and Figs. 2a-2c show a schematic side view, in cross section, in the part of the band strap in which the sensor system (fight emitting and receiving surfaces is positioned during use).

The wrist worn device includes a securing band 2, a processing unit 4, an integrated or separate wireless communications unit 6, a fight emitting and light receiving unit or sensor element 8 positioned on top of one or both of the main arteries, Ar, Au, in the wrist W and a static pressing element 9. In this example, the device 1 includes three fight sources each having a fight emitting surface 12. In this example, the device 1 also includes three fight receivers having each a fight receiving surface 16. One or two of the light emitting and receiving surfaces are being used to perform physiological measurement, whereas at least one set of fight emitter and receiver is being used for detection of motion artefacts via measurement of all fight reflected on the skin. The fight emitting surfaces 12 and the fight receiving surfaces 16 are arranged on the inside of the securing band 2 of the wrist worn device 1 such that when worn the at least one light emitting surface 12 and the at least one light receiving surface 16 substantially abut against the palmar side of the wrist of a user, preferably at the side of the wrist where the ulnar artery Au and/or radial artery Ar are located. Additionally in this embodiment the light emitting surfaces 12 and the light receiving surfaces 16 are separated by a non-transparent light blocker 13, which can be made from a flexible, compressible material. Furthermore, in this example the light emitting surfaces 12 and the light receiving surfaces 16 are received in an elastic frame 10 and 14, respectively, of light blocking material. Finally a spherically shaped partly transparent polymer cover 26 can be provided, which enhance the pressing into the skin and the light coupling and which can have nontransparent light blocking segments between the LEDs and PDs.

In this example, the static pressing element 9 is made from a deformable, compressible material. The static pressing element 9 is mounted in a tunnel shaped pocket 11 (see fig 2d) of the securing band 2, which can either be in the longitudinal direction of the securing band or in the width direction or both.

The static pressing element 9, can be made of foam, a deformable plastic moulded part, a spring element, a spacer fabric or 3D-textile element or the like. The pressing element 9 has a raised area 9A which presses underneath the sensor element 8 with the light emitter 12 and light receiver 16 so that these are pushed into the skin on top of the ulnar artery Au and/or radial artery Ar. The position of this static pressing element 9 and thus also it’s raised area 9A can be varied by shifting/sliding the pressing element 9 inside the tunnel shaped part 11 of the securing band 2. The sliding can be done manually after having performed the first signal amplitude measurement, either via sliding the static pressing element 9 from the inside of the band 2 via pulling and or pushing, via the outside via an integrated sliding handle 13 (see fig 2c) or automatically in a self-seeking manner. For this last embodiment the static force pressing element 9 can have a low friction smooth surface that enables easy automatic sliding inside the tunnel 11.

In this example, the tunnel is made of a polymer and/or textile material and has a larger elasticity and elongation capacity on the inside, skin side, than on the outside, in order to force the static pressing element 9 with it’s raised area 9A to press the light emitting surface 12 and light receiving surface 16 into the skin. The static pressing element 9 is arranged for exerting a force on the light emitting surfaces and light receiving surfaces in a direction substantially perpendicular to the palmar side of the user’s wrist. In this tunnel also the rigid beam lever 71 can be mounted (see fig. 8), which applies more pressure on the light emitting an light receiving surfaces at the skin area above the main wrist arteries.

The static force pressing element 9 can also have the shape of a rectangular, square or oval shaped part (24) with flanges (22) which can be mounted in a deformable stretchable pocket (11) on the inside of the securing band 2 (see fig 6). This part 24 has one or two or more raised areas which can be lowered in height via compression enabling by this a higher pressing force to the skin when the fight emitting and fight receiving surfaces 12, 16 are mounted above this part on the inside of the securing band.

The securing band or strap can include one or more sections of stretchable textile materials and or polymer materials enabling a tight securing and delivering an initial pressing force for the actuators and fight emitting and fight receiving surfaces. The entire circumference of the securing band or strap can also be made of such material.

The securing band or strap can include a stretchable foam material which is permeable to water vapour, sweat and gasses, allowing ventilation of the skin. Such foam material can on the side abutting the arm or wrist be covered with a textile material allowing absorption and uptake of sweat, regulating the microclimate and preventing allergic reactions. The entire circumference of the securing band or strap can also be made of such foam material. This foam material can be coated with a stretchable textile material enabling a high comfort and easy moisture uptake from the skin

The securing band or strap further can comprise one or more sections, or be completely made, of stretchable material textile and or polymer materials enabling a tight securing and delivering an initial pressing force for the static force pressing element and light emitting and light receiving surfaces.

The securing band or strap further can comprise a stretchable foam material which is permeable to water vapour and gasses, allowing ventilation of the skin. The foam material can on the arm or wrist side be covered with a fine textile material allowing absorption and uptake of sweat, regulating the microclimate and allergic reactions.

The hght receivers 16 are arranged for producing a received fight signal corresponding to a received intensity of the hght received at the at least one hght receiving surface 16. The processing unit 4 is arranged for determining an amplitude of the received hght signal.

During a measurement session the amplitude of the received hght signal can be increased by varying the position of the static force pressing element and or the selection of the most appropriate hght emitting surface and hght receiving surface. Measurements derived from a received hght signal where the amplitude of the received hght signal has a distinctive value in which the AC part of the heart pulsating can be clearly discriminated from the DC part including the motion artefacts in this DC-part of the signal. By this the signals during a measurement session are more rehable. Also the effect of motion artefact and movement which is measured by the hght reflection on the skin can be used in the dataprocessing in the unit 4 to be able to clearly discriminate the heart beat signal. In this example, a user’s heart rate and heart rate variability are determined on the basis of the received light signal.

Additionally, in this example the three light emitting sources are each capable of emitting light in a first wavelength range and a second wavelength range. In this example, each light source comprises a first LËD capable of emitting light in a first wavelength range of 600-660 nm and a second LED capable of emitting light in a second wavelength range of 880-940 nm and a third LED capable of emitting light in a second wavelength range of 1100-1400 nm or 400-500 nm.

By performing a first measurement session wherein the light emitted by the three light sources in the first wavelength range and performing a second measurement session wherein the fight emitted by the three fight sources is in the second wavelength range additional health indicators such as the user’s saturation of peripheral oxygen level, Sp02, can be determined. This is determined on the basis of a ratio of the perfusion index value (AC/DC value) calculated in the first measurement session and the perfusion index value calculated in the second measurement session.

In this example, prior to performing a measurement session a selection step is performed. In the selection step a fight source and light receiver combination is selected. For each fight source of the three light sources, fight is emitted in a wavelength range for a predetermined amount of time. A received fight signal is produced at each of the fight receivers. The processing unit 4 separates each received fight signal into a high frequency component and a low frequency component using filters with cut-off frequency values that are based on the lowest expected heart rate and the highest expected heart rate. A perfusion index value is calculated for each received fight signal by the processing unit 4 on the basis of a ratio of the high frequency component and the low frequency component. The steps are repeated for each fight source, and the fight source and fight receiver combination having the highest perfusion index value is selected. It is possible that after this selection the non-selected light sources are switched off to reduce power consumption. A system 100 inducting a wrist worn device 1 and a communications device 50 is shown in Fig. 3. The communications device 50 indudes a display 52, e.g. a touch screen display, which gives information, feedback and instructions to the user. A software application running on the processing unit 4 or the communications device 50 can also be used to define, start and install measurement sessions. In this example the display 52 is assodated with the wrist worn device. Additionally both the communications device 50 and the wrist worn device 1 indude a communication unit, not pictured, through which the devices are able to communicate with each other. In this example the communications device 50 can for instance be a smart phone device with a touch screen display.

With the system 100, a user can monitor his general fitness. In addition, a user and/or a health advisor can monitor a user’s compliance to a selected exerdse schedule, can measure his/her daily exercise, his heart rate and oxygen saturation values during exercise, before and after exercise etc. For example, in Fig. 4, an exerdse instruction 54 appears on the display 52 of the communications device 50. For example, the instruction 54 instructs the user to perform e.g. twenty knee bendings (so called squats). During the exercise a measurement session is performed. Preferably, a measurement session is performed prior to starting the exerdse and, e.g. at predefined intervals, after the exerdse is completed. It is possible that the wrist worn device 1 concludes that the exercise is completed on the basis of at least one of an amount of movement determined on the basis of the received light signal, an amount of movement determined by an accelerometer of the wrist worn device, and a measured elapsed time interval.

In this case during each measurement session the user’s heart rate, heart rate variability, heart rate recovery and oxygen saturation, Sp02, is measured. On the basis of these measurements recorded during different measurement sessions, an indication of a user’s general fitness indication of the user’s health is determined.

On the display 52 of communications device 50 associated with the wrist worn device 1, an indication 56 of the general fitness of the user is displayed. The indication 56 may relate to the general fitness just measured during the exercise. Additionally, or alternatively, the indication 56 may relate to a general fitness measured on the basis of the measurement session and one or more previous measurement sessions, for example measurement sessions taken over the previous week or month.

In this example, the indication 56 is a graphical representation of a person having a general fitness corresponding to the general fitness of the user or an activity pattern or movement achievement during a certain amount of time. In Fig. 4, the measured general fitness of the user is poor. Therefore a graphical representation 56 of a person having a poor general fitness is shown. In this example, the graphical representation 56 is of an overweight person. Additionally, in the case that the graphical representation 56 of the person is animated, the animation can represent the general fitness of the user, e.g. graphical representation 56 of the person can be animated to be breathing heavily.

In Fig. 5, the measured general fitness of the user is good. Therefore a graphical representation 56 of a person having a good general fitness is shown. The graphical representation 56 is of healthy person of normal build. Additionally, in the case that the graphical representation 56 of the person is animated, the graphical representation 56 of the person can e.g. be running in place.

The indication 56 of a general fitness of the user can also be measured on the basis of measurement session initiated in response to an amount of movement being detected by the integrated optical motion artefact and movement detection system, and if necessary with additional sensors such as provided accelerometers provided, not pictured, in the wrist worn device, or GPS positioning data and or GSM tri-angulation data. The amount of movement and the measured health status are recorded in the wrist worn device 1 and/or the communications device 50. In this way a measure of compliance to an exercise schedule is measured. For example, the schedule might require that the user performs 30 minutes of exercise a day at or above the users target heart rate. In the case of Fig. 5, the user has achieved a 90 % compliance. In the example of Fig. 5 this is displayed as a text 58, including an encouraging comment, on display 52 of the communications device 50.

In the foregoing specification, the invention has been described with reference to specific examples of embodiments of the invention. It will, however, be evident that various modifications and changes may be made therein without departing from the broader spirit and scope of the invention as set forth in the appended claims. For the purpose of clarity and a concise description features are described herein as part of the same or separate embodiments, however, alternative embodiments having combinations of all or some of the features described in these separate embodiments are also envisaged.

Fig. 7 shows an alternative version of the static force pressing system with a piston system. In this embodiment the pressing force on the skin 74 with the spherical or otherwise shaped dome with transparent cover 26 with sensor 16 and LEDs 12 can be applied via an adjustable piston system 62 which glides and locks its rim 63 in predetermined positions 61. This piston system 62 with its corresponding cylinder 60 has a contact surface 64 on the outside of the securing band or strap 59 which can be pressed with a finger 65 to adjusting the pressing force dome with the light emitting surfaces 12 and light receiving surfaces 16 more or less on the skin 74 to achieve a better heart rate signal from the main arteries in the wrist Ar and or Av. The polymer material 13 between the light emitters 12 and fight receivers 16 can be opaque and non transparent to block cross transfer of fight directly to the sensor. The polymer material can be elastic and compressible. The transparent polymer cover material 26 can also be elastic and compressible. The piston system 62, 60 can have an in built spring or lever to release the part 63 via pushing to a higher position. The piston system can have predetermined positions 61 or can have unlimited variable positions not predetermined.

Fig. 8 shows a stiff damp and beam lever system 71 with a cylindrical, round, spherical, or otherwise shaped end 67 which can exert a force on the back side of the dome shaped sensor unit containing the light emitting surfaces 12 and light receiving surfaces 16 to push this more or less into the skin 74. The light and sensor unit is either mounted in a partly flexible strap 59 or can be slidingly moved upward and downward like in a piston system of fig 7 or in an axis and corresponding cylinder system, The beam lever 71 rotates or moves with a cylindrical or dome shaped end 69 in a corresponding casing 70 depending on the amount of fastening of the securing band or strap 59 in one of the positions 73 with the corresponding elements 72. This damp or beam lever system can have various shapes, sizes or different constructions, but always will be able to push the fighting and sensing unit harder or less harder into the skin 74 above one or two of main arteries Ar or Av of the wrist to detect the heart rate better and other physiological parameters. An alternative version of this embodiment comprises a half circular stiff polymer or metal element, which rests on upper part of the wrist and near the artery and is half circular or covering the outer and inner side of the wrist. This beam lever or damp 71 is integrated in the partly or wholly flexible strap 59 and will push the fighting and sensor unit more or less in the skin 74 to achieve a better measurement. The stiff beam lever 71 has a slight larger curve or radius then the side of the wrist and due to its stiffness will push itself inwardly in the direction of the arteries Ar and or Av pushing the fight emitting and receiving surfaces doser to one or two of these arteries. Also other beam lever or damp versions are possible, with the basic prindple that a stiff or stiffer element of the strap pushes the lighting and sensing unit deeper or less deeper in the skin.

Fig. 9. shows a compressible non-transparent shield 73 around the light emitting and light receivers 12 and 16 which blocks ambient light and allow a high comfort during wearing. The shield is deformable due to its shape and or use of flexible, compressible material. The shield 73 has ends 72 which can rest upon the skin and block all ambient light from the environment. The shield can have a bellows shape or another deformable shape allowing compression after applying force on the fastening strap, or clamp, beam lever system of fig. 8 or piston system of fig. 7 or via another method.

However, other modifications, variations, and alternatives are also possible. The specifications, drawings and examples are, accordingly, to be regarded in an illustrative rather than in a restrictive sense.

For the purpose of clarity and a concise description features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word ‘comprising7 does not exclude the presence of other features or steps than those listed in a claim. Furthermore, the words ‘a7 and ‘an’ shall not be construed as limited to ‘only one7, but instead are used to mean ‘at least one’, and do not exclude a plurality. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

An apparatus for measuring a user's health condition that is worn around the wrist of a static or moving user, the instrument comprising a fastening band, at least one light source with a light-emitting surface and at least one light receiver with a light receiving surface; wherein at least one light source and at least one light receiver are positioned on the fastening band such that when the device is worn, at least one light emitting surface and at least one light receiving surface are adjacent to and against the inside, palmar side of the user's wrist. The apparatus further includes a pressure element projected on the side of the fastening band and directed toward the wrist such that one light emitting surface and at least one light receiving surface are pressed into the skin of the wrist. The device further includes at least a second light source and at least a second light receiver that are different from the first set and whose light cannot penetrate deep into the skin and the corresponding sensor is thereby able to detect motion artifacts and instrument movement.

An apparatus according to claim 1, wherein the pressure element, such as a fixed part or an compressible part, such as a foam part or a spring system, which can be manually adjusted to adjust the pressure force.

Apparatus according to claim 1 or 2, wherein the pressure element has a dome shape, such as e.g. a rounded shape, a pyramid shape, hemispherical part; a half oval part; a rounded diamond shaped part and consists of a movable inner core part and outer conductive part.

Apparatus as claimed in claim 1 or 2, wherein the pressure element consists of a fixed and non-compressible part that has a dome shape, such as e.g. a rounded shape, a pyramid shape, hemispherical part; a half oval part; a rounded diamond shaped part and consists of a movable inner core part and outer conductive part.

Apparatus as claimed in claim 1 or 2 or 3 or 4, wherein the pressure element is connected directly or indirectly to a clamp or lever system which can press the light-emitting surface and the light-receiving surface into the skin of the wrist.

The device of any one of claims 1-5, wherein the light source and light receiver are both covered with a polarizing system, e.g. a polarization filter, to limit the penetration of light and to maximize the reflection of light to be able to detect motion artifacts and motion.

The device of claim 6, wherein the polarizing system, polarizing filter, for the optical sensor or the light receiver is rotated 90 degrees relative to the polarizing filter for the light source or light emitters to be able to detect motion artifacts and motion.

Apparatus according to any of claims 1-7, wherein the light-emitting and light-receiving surfaces are shielded from ambient light by a non-transparent, light-blocking screen that touches the skin.

The device of claim 8, wherein the light-emitting and light-receiving surfaces are shielded from ambient light by a compressible and deformable, non-transparent, light-blocking screen that touches the skin.

An apparatus according to any of claims 1-9, wherein a modulation scheme is used for the emitted emitted light in such a way that the ambient light present in both the high light intensity measurement and in the low light intensity measurement is thereby eliminated from the light that is related to the physiological parameters, in the software or firmware of the device.

Apparatus as claimed in any of claims 1-10 wherein an compressible material or element is present around or behind the light-emitting and light-receiving surfaces to block the crossing light directly between light-emitter and light-receiver and to provide a higher comfort for the user to ensure.

The device of any one of claims 1 to 11 wherein the pressure element is positioned above one or both of the main arteries in the wrist.

Apparatus according to any of claims 1 to 12, wherein the pressure element is placed at least in part between the fastening band and / or the light-receiving surfaces.

Apparatus according to any of claims 1 to 12, wherein the pressure element is placed at least in part between the fastening tape and / or the light-receiving surfaces.

An apparatus according to claim 13 or 14, wherein the pressure element is received in a tunnel-shaped part of the fastening tape or is mechanically connected to the fastening tape.

An apparatus according to any of claims 13-15 wherein the pressure element is included in such a way that it is movable in the circumferential direction or axial direction of the fastening tape.

The apparatus of claim 16, wherein the pressure element is included in such a way that it is slidable.

An apparatus according to claim 17, wherein the surface of the pressure element and / or a surface of the fastening band, carrier, tunnel-shaped part facing the pressure element has low friction to allow easy sliding.

An apparatus according to any of claims 16-18, wherein the pressure element has a positioning means facing the outside of the fastening tape, to allow positioning and displacement of pressure element.

The apparatus of claim 19, wherein the positioning means is a handle that protrudes from one side of the fastening tape, and / or protrudes radially through the fastening tape.

Apparatus as claimed in any one of the preceding claims, wherein the fastening strap consists partly or entirely of extensible material to enable the tightening element to be pressed into the skin by tightening it and exerting a pressure force.

An apparatus according to claim 21, wherein the fastening tape consists of an extensible foam material that is permeable to water vapor and gases, thereby allowing ventilation of the skin, wherein optionally the foam material can be covered on the wrist side with a material that can contain liquid and moisture absorb.

Apparatus according to any of the preceding claims, further comprising a control unit adapted to determine a health condition, such as a physiological parameter, such as heart rate, heart rate variability, heart rate recovery rate, respiratory rate and / or oxygen saturation, CO2 values, of a signal representative of the amount of light received by the light receiver.

An apparatus according to any of the preceding claims, wherein the light-emitting surface (s) and the light-receiving surface (s) are separated from each other by a non-transparent light blocker.

An apparatus according to any of the preceding claims, wherein the light-emitting surface (s) and the light-receiving surface (s) are contained in one or more elastic, compressible containers, preferably made of light-blocking material.

Device according to any of the preceding claims, wherein the light-emitting surface (s) and the light-receiving surface (s) are covered with a transparent layer or cover, preferably a dome-shaped, partially spherical cover.

An apparatus according to any of the preceding claims, further comprising a wireless communication module for communication with a communication device, such as a smart phone with a display, a tablet or a smart watch.

An apparatus according to any of the preceding claims as far as dependent on claim 23, wherein the fastening tape is provided with woven, knitted and or embroidered electrically conductive connecting wires connecting at least one light source and at least one light receiver to the control unit.

An apparatus according to any of the preceding claims, wherein at least one light source comprises an optical fiber for guiding light to the skin of the user and / or wherein at least one light receiver comprises an optical fiber for guiding the light from the skin of the user.

The device of claim 29, wherein the optical fiber is woven, knitted and / or embroidered in the fastening tape.

The apparatus of claim 29 or 30, wherein at least a portion or section of the optical fiber that is positioned to touch the skin of the user is treated to make light easier to couple.

An apparatus according to any of the preceding claims, insofar as dependent on claim 1, wherein the processing module is arranged to detect whether the apparatus has been properly worn around the wrist based on the received light signals from an array of light sources used for physiological measurement, motion artifact measurements and ambient light level measurements.

An apparatus according to any of the preceding claims, further comprising an acceleration sensor adapted to detect the amount of movement of the user's wrist.

An apparatus according to any of the preceding claims, as far as dependent on claim 23, wherein the softening module is adapted to determine a blood composition of the user (hemoglobin, hematocrit, albumin values) for medical purposes, such as blood abnormalities after chemotherapy and / or radiation therapy, blood loss after birth or in the event of an accident, infections with tropical diseases such as Denque (cockle fever).

35. Method for measuring and determining a user's health status, general fitness, and / or complying with and following a user's exercise schedule, consisting of the following steps: Providing the user with a device around the wrist of the user, comprising a fastening tape, at least one light source having a light-emitting surface and at least one light receiver having a light-receiving surface; wherein the device comprises at least one light source and at least one light receiver disposed on the fastening tape of the device such that when worn, at least one light emitting surface and at least one light receiving surface rest against the inside, the palmar side of the wrist of the user and execution of a measurement session consisting of: emitting light in a wavelength region by at least one light source for a predetermined period of time; a light signal produced by at least one of light receiver corresponding to the received intensity of light on at least one of the light receiver; controlling the received light signal by applying a compressive force to at least one light-emitting surface and / or at least one light-receiving surface in a direction that is substantially perpendicular to the palmar side of the user's wrist; determining the influence of motion and motion artifacts by analyzing the received light signal from another light emitting source that is unable to penetrate deep into the skin and whether it has a high water absorption rate (400-550 nm or 1100-1400 nm) )

The method of claim 35, including a possibility to adjust the magnitude of the applied force.

A method according to claim 35 or 36, comprising a possibility to adjust the position of the applied force on the palmar side of the wrist.

The method of claim 35, 36 or 37 further comprising controlling the amplitude of an alternating signal component of the received light signal as a result of the pulsing blood to be adjusted by applying the appropriate force.

The method of any one of claims 35 to 38, further comprising a control of the received light signal by manual adjustment and adjustment of the compressive force.

A method according to any of claims 35-39, further comprising a control of the received light signal by the control of the emitted light from at least one light source.

A method according to any of claims 35-40, as far as dependent on claim 38, further comprising determining the amplitude of the alternating signal component, by the measured received light signal during a predetermined period of time and determining the amplitude of the alternating signal component of the measured received light signal during the predetermined period

A method according to any of claims 35-41, further comprising determining the user's heart rhythm based on the received light signal based on time and / or frequency domain analysis, and optionally based on an amplitude value of a control signal of the control unit for controlling the transmitted intensity and optionally based on a mathematical correction of the influence of motion artifacts and motion measured with the separate light source and sensor combination.

A method according to any of claims 35-42, further comprising performing a first measurement session in which the emitted light is from at least one light source in a first wavelength region, performing a first measurement session in which the emitted light is from at least one light source is in a second wavelength region and wherein the emitted light is from at least one light source in a third wavelength region.

The method of claim 43, wherein the step of performing a measurement session further comprises a step in which the perfusion index value is calculated based on the received light signal; and wherein the method further comprises determining the saturation of the peripheral oxygen level based on the ratio of the perfusion index value as calculated in the first measurement session and the perfusion index value as calculated in the second measurement session and optionally or based on the value of a control signal from the control unit for controlling the emitted light intensity.

The method of any one of claims 35 to 45, wherein at least one light source comprises a plurality of light sources and at least one light receiver comprises a plurality of light receivers.

A method according to 45, wherein the step of generating and creating the received light signal from at least one light receiver includes averaging of the received light signals generated by a subset of the multiple head receivers.

The method of claim 46, wherein the step of generating and creating the received light signal from at least one light receiver includes a selection and selection of the most optimum signal produced by one of the light receivers.

The method of claim 47, wherein the step of generating and creating the received light signal from at least one hand receiver includes a selection and selection of the best and second best signal produced by one of the hand receivers.

The method according to claim 48, further comprising a selection step of at least one light source from the plurality of hold sources and selecting at least one hold receiver from the plurality of hold receivers, wherein the selection step includes: for each hold source of the plurality of hold sources that emit hold in a wavelength range for a predetermined period of time; producing at each light receiver a separate light signal corresponding to the received light on said light receiver separately from each light source from each received light signal in a high frequency and a low frequency component; calculating the perfusion index value for each received light signal based on the ratio between the high frequency component and the low frequency component and selecting a light source and light receiver combination that has the highest perfusion index value of at least one light source and at least one light receiver.

The method of any of claims 45-49, further comprising selecting a subset of light sources from the plurality of light sources and a subset of light receivers from the plurality of light receivers that have the highest perfusion index of at least one light source and at least one light receiver.

The method of claim 49 or 50, wherein the selection step is performed for a first wavelength range and a second wavelength range.

A method according to any of claims 36-51, further comprising a step of displaying an instruction on a display connected to the wrist-worn device and instructing the user to perform a predetermined exercise; further comprising performing a measurement session while the user performs the predetermined exercise; and storing the result of the measurement session, which preferably includes the user's heart rhythm and / or oxygen saturation level and / or the user's ability to quickly return the heart rhythm to a normal, non-invasive level au.

The method of claim 52, further comprising: measuring the general fitness and condition of the user based on the measurement session and / or previous measurement sessions; The display of an indication of the general fitness and condition of the user, preferably including a graphical representation of a person who has a general fitness corresponding to the general fitness of the user.

The method of claim 53, wherein the graphical display moves and is colored corresponding to the general fitness of the user and / or following the exercise schedule.

A method according to any of claims 1-54, for measuring motion, measuring activity of the user based on the heart rhythm, the measurement of degree of motion artifacts and motion using a separate light source and sensor.

The method of claim 55 for measuring motion, user activity based on heart rate measurement, the measurement of motion artifacts and motion using a separate light source and sensor, and the measurement of the local position and motion with the GPS receiver in the device itself or in another auxiliary device.

A method according to claim 55 or 56 for measuring movement, user activity based on the heart rhythm measurement, the measurement of movement artifacts and movement using a separate light source and sensor, and the measurement of the local position and movement with a triangulation GSM measurement.

A method according to claim 55 or 56 or 57, to measure movement, activity of the user on the basis of the heart rhythm measurement, the measurement of the extent of movement artifacts and movement using a separate light source and sensor, and the measurement of the local position and movement with a triangulation GSM measurement and a skin temperature sensor.