FI12263U1 - Optical sensor of human pulse waveform - Google Patents

Abstract

An optical sensor for pulse waveforms of a human, which optical sensor contains an emitter module (1) and a light receiver module (4) arranged in kinematically connected housings (3.5), the output of the light receiver module (4) being the output of the sensor, further comprising an optical sensor (6, 7) for positioning the light receiver module (4) relative to the emitter module (4), said means (6, 7) comprising an elastic member (7) connected to both the emitter module (6). 1) and the light receiver module (4) and allowing a movement of the light receiver module (4) relative to the emitter module (1) while securing its positions to the surface of a person's skin; characterized in that an outer shape of the surface of an emitter holder (2) is configured to lie against a lower part of an inner surface of the person's ear lobe, the emitter holder (2) being made of an opaque elastic material, and the positioning means comprising a linear guide means (6) having an axis extending parallel to an optical axis joining the emitter (1) with the light receiver (4) while securing the coaxial position of the emitter (1) and light receiver (4). In addition, protection requirements 2.

Description

OPTICAL MEASURING DEVICE FOR WAVE PULSE OF HUMAN PULSE

Field of the Invention

The present invention relates to medicine and, in particular, to the functional diagnosis of the human condition, can be used for medical research, including hemodynamic studies, and systems for monitoring the degree of fatigue of vehicle drivers.

Background of the Invention

The pulse waveform caused by blood flowing in the human arteries contains information related to the condition of said human cardiovascular system. Such information is critical to predicting the influence of adverse environmental factors on the adaptability of the human body. One of the most widely used methods for registering a pulse waveform is sphygmography. This method uses sensors placed directly on the person's skin, directly above the arteries. The pulse waveform is recorded by mechanical or optical methods based on sensor movements caused by the enlargement of the subcutaneous volume of the artery.

A pressure sensor is known in the art (RU2430344, G01L 9/08, published September 27, 2011, Bulletin 27), comprising a body, a circular metal film, a plate-shaped piezoelectric quartz cell mounted on a crystal holder surface parallel to the film with a gap between the cell and the film. wherein the center points of the plate-shaped piezoelectric cell and membrane are aligned with the longitudinal axis of the crystal holder, and the circular electrode, a metal base comprising the base member, the inner protrusion and the inner groove, the metal support ring having has a flat cylindrical end, a flexible flat member having a central aperture through which the rivet passes, and an adjusting screw having a spherical end, which is screwed into a threaded hole in the center of the base of the metal base and which is spherical the head end contacts the flat surface of the rivet head and forms a solid connection between the crystal holder and the inner outer periphery of the sole and the inner surface of the support ring, the lower surface of the support ring supporting the metal foil, the outer cylindrical surface of the support ring the depth of the surface in the bottom portion of the latter is limited by an inner protrusion and wherein the upper and lower surface of the support ring and the surface of the bottom protrusion are parallel to the crystal holder surface, with a flat piezoelectric quartz cell and a circular electrode positioned The sensor further comprises a first pneumatic filter formed by a pneumatic filter and a reactor throttle which are in contact with each other and formed by a vertical cylindrical channel in the side sidewall of the base filled with filter material such as a felt and a a second pneumatic channel formed by a cylindrical passage, a portion of which is filled with filter material, and a horizontal cylindrical passage having a spring-loaded compensation valve formed by a ring formed along the surface of the cylinder, said passages communicating with the pneumatic the inlet and reactor choke outputs of the second pneumatic channel outlet are connected to the walls , the volume defined by the bottom of the base and the surface of the inner diaphragm, said volume communicating with the body inlet through a second pneumatic channel by means of a compensation valve when the sensor is reset. The piezoelectric sensor is used for sphygmography by means of an occlusive cuff located around the arm.

In addition to touch sensors, non-contact pulse waveform sensors are known in the art. A transducer of a semiconductor laser device is described in DA Usanov, AV Skripal, EO Kaschavtsev, "Determining Pulse Waveform Based on a Semiconductor Laser Autodyne Signal", Journal of Technical Physics, Vol. 39, B. 5, pp. 82-87, 2013. , comprising a laser diode of quantum size superimposed on InGaAIP structures having a single spatial boundary limited by diffraction and having a radiation wavelength of 654 nm, having a stabilized electric current source for the laser power requirement and a photocell to measure the output of the laser. When performing sphygmography with the sensor described above, laser radiation must be directed to the surface of the skin in the area of the wrist where the vein is closer to the surface of the skin. The portion of radiation reflected from the skin surface returns to the laser resonator, whereby it changes the output of laser power as the pulse waveform passes through the artery. The change in laser power is recorded by a photocell and its output signal is sent to a data processing and storage system.

The drawbacks of the prior art devices described above include the complexity and inadequacy of their design when worn for long periods of cardiovascular monitoring, particularly for early monitoring of vehicle occupants.

Many different sensors for monitoring the physiological parameters of the human cardiovascular system are known in the art, including measuring blood oxygen levels; such sensors are simple and can be kept on. Such sensors are described, for example, in the following patents: US 7263396, A61B 5/00, issued August 28, 2007; US 8532729, A61B 5/1455, issued September 10, 2013; US 8588880, A61B 5/1455, issued November 19, 2013. Structurally, such sensors are ear clips that are mechanically fitted to the human body for attachment to the ear region, mainly the earlobe. Such sensors include radiation sources and light receivers that allow optical transmittance of blood-rich biological tissue and the recording of blood oxygen levels.

The prior art solution of the present invention is a wearable physiological sensor (US 8229532, A61B 5/1455, published July 24, 2012) comprising an emitter module and a light receiver module housed in kinematically connected enclosures, wherein the output of the light receiver module is a sensor output, means for positioning the light receiver relative to the transducer module, said member comprising a resilient element connected to both the emitter module and the light receiver module, which allows the light receiver module to move relative to the emitter module while its position is fixed against the skin surface of the person's ear.

The main disadvantage of the prior art solution is its low accuracy in pulse waveform registration.

Despite the apparent simplicity of the structure, wearable oximetric sensors are demanding devices that perform very complex diagnostic tasks. Patient health (and in some cases, patient life) depends on the accuracy of the readings of such sensors. D.A. Rogatkin, "Physical basics of optical oxymetry", Medical Physics, 2012, Issue 2, p. 97-114. describes in detail the features of the various devices when used in a non-invasive diagnostic method to estimate the percentage of oxyhemoglobin in the blood. The requirements for the development and production of optical oximeters are described in International Standard Publication ISO 9919: 2011, Medical electrical equipment - Particular requirements for basic safety and essential performance of pulse oximeter equipment.

The high accuracy requirements for wearable optical pulse waveform sensors for sphygmometric and oxymmetric measurements, and the requirements for securely attaching devices to the body of supervised persons for long periods of time in a variety of climatic and outdoor lighting conditions are likely to be summarized as accidental contact with clothing while maximizing the number of capillary blood vessels in the body; • Attach the sensor to the body as much as possible without unintentional movement of the sensor due to human movements, while avoiding any discomfort caused by blocking or disrupting the circulation of the attachment area. The sensor should be as light as possible; • The sensor design must prevent or minimize exposure of the light receiver to external light sources, while providing the highest signal-to-noise ratio possible; • For attaching the organ sensor to the human body, it must be possible to adjust the positions of the emitter and receiver to the physiological characteristics of the subject without altering the calibration parameters of the device or the methods of data analysis of the received data.

Summary of the Invention

It is an object of the invention to provide a better accuracy in measuring pulse waveform and human hemodynamic parameters by providing a better signal-to-noise ratio as a technical result.

The described technical result is achieved by an optical human pulse waveform sensor, the optical sensor comprising an emitter module and a light receiver module housed in kinematically coupled enclosures, wherein the output of the light receiver module is the sensor output, the optical sensor further comprises a both the emitter module and the light receiver module, and which allows the light receiver module to be moved relative to the emitter module, while its positions are secured against a person's skin surface; wherein the outer shape of the emitter holder surface is formed to abut the inner surface of a person's earlobe and the groove between the tragus and antitragus, wherein the emitter holder is made of opaque plastic and wherein the insertion member includes a linear guide ensures the coaxial position of the emitter and the light receiver.

In addition, the emitter of the optical sensor may comprise two radiation sources, the wavelengths λΐ and Λ2 of which are selected to be in the defined spectral ranges λΐ = (640-720) nm and Λ2 = (960-1040) nm.

Analysis of the human pulse waveform (sphygmogram) provides indications of a person's general physiological condition and, in particular, the condition of the cardiovascular system, i.e. blood flow to and from the capillaries, vascular tone and elasticity, vascular volume filling, elasticity of large vascular walls Examining the pulse waveform using visible light transducers involves attenuating the radiation of blood-filled tissues in different areas of the spectrum. The process involves recording changes in the vascular volume and pulmonary oxyhemoglobin concentration (transmission difference at different wavelengths) occurring during the pulse wave (sphygmogram waveform). It should be noted that hemodynamics is solely determined by the waveform of the sphygmogram, whereas the oxygen concentration in the blood affects the amplitude of the waveform, assuming that blood oxygen levels remain generally constant over a single pulse wave period. In particular, the accuracy of the measured hemodynamic property and the performance of the sensor generally depend on compliance with the essential requirements of the sensor design and attachment to a person's body.

The structure of the present invention encompasses a number of new technical solutions (features of the circuitry claims), the combination of which produces a compliant technical result, which features: 1) The outer shape of the emitter holder surface is formed against the underside of a person's earlobe . This allows the sensor to be securely attached to a person's body in an area that is not easily contacted indirectly by clothing but has a sufficiently dense capillary network. Unlike prior art sensors adapted for earloop attachment, the structure of the present utility model provides attachment to the cartilage of the ear, eliminating any discomfort (numbness) caused by prolonged use of the transducer, and further generates a vascular higher level and better quality of the sensor output signal. In addition, the sensor center of gravity is located between the sensor and the optical axis of the positioning element guide. This arrangement allows the torque and its effect on the sensor output signal to be minimized during use (minimizing noise levels due to natural head movements) while maintaining the aesthetic appearance of the sensor being used, which is particularly important for women. 2) To prevent exposure of the sensor light receiver to the outside air caused by radiation from external sources, the emitter is provided with an opaque holder having an outer surface of the emitter facing the inner surface of the underside of the ear and the outer surface of the antitrag. I had to reduce the exposure levels of the light receiver under changing light conditions and reduce the pressure on the earlobe to improve comfort during long-term use. 3) The sensor structure allows for personal adjustment of the relative position of the emitter and light receiver modules while maintaining their orientation with a linear guide.

Brief Description of the Drawings

The present invention will be described with reference to the accompanying drawings.

Figure 1 is a general view of the sensor depicted,

Figure 1 is a sectional view of the sensor structure,

Figure 3 is a diagrammatic view of the human ear showing the position of the sensor,

Fig. 4 shows the results of a comparative test of the described sensor and the prior art sensor confirming the validity of the technical result according to the appended claims.

Figure 2 has the following reference numerals: emitted 1; emitter holder 2; emitter module housing 3; light receiver 4; light receiver module housing 5; linear guide 6; and springs 7.

Figure 3 shows the following reference numerals: tragus 1; antitragus 2; a groove 10 between the tragus and the antitragus (the shaded area corresponds to the contact area of the emitter holder 2 of the described sensor); and ear leaf 11.

The sensor described comprises an emitter 1 mounted on a holder 2 arranged in a housing 3 of an emitter module 1 and a light receiver 4 mounted on a holder 5 housed in a housing 5 of a light receiver module 4. The emitter 2 comprises for example a red LED and an infrared LED radiation in the spectral regions (640-720) nm and (960-1040) nm, respectively, since the end coefficients of oxyhemoglobin and deoxyhemoglobin are known to differ significantly in the above ranges. The housings 3 and 5 of the emitter module 1 and the receiver module 4, respectively, are made of a lightweight and durable plastic material, for example polycarbonate. The structure of the sensor described allows the housing 3 of the linear emitter module 1 to move relative to the housing 5 of the light receiver module 4 along a linear guide 6 with its axis parallel to the optical axis of the device connecting the detector element of emitter 1 and light receiver 4. The linear springs 7 mounted on each side of the linear guide 6 provide a "pull" force, whereby the emitter 1 is directed towards the light receiver 4 in any position due to the operation of the linear guide 6. The holder 2 of the emitter 1 is made of a flexible opaque material, for example carbonized silicone. This embodiment of the holder prevents the light receiver 4 from being exposed to the outside air.

Fig. 4 is a graph showing two waveforms of a patient under study, receiving data from two sensors having the same optical / electronic pattern but different structure. The lower diagram shows the pulse waveform of the prior art, while the upper diagram shows the waveform obtained using the sensor of the appended claims. In addition, the magnified view shows the areas of each curve with local maximum values. Analysis of the pulse waveforms shows that the signal / noise ratio of the present utility model exceeds prior art sensors by about 30 dB. This higher quality results in better accuracy in the recording of human hemodynamic parameters. The magnified area (view A) clearly shows the characteristics of the pulse waveform at the maximum local area, while the state of the art waveform (view B) completely obscures such properties. Therefore, the described human pulse waveform optical sensor comprises a combination of features which, as a technical result, result in an increase in measurement accuracy due to an improved signal / noise ratio.

Claims (2)

PROTECTION REQUIREMENTS An optical sensor for human pulse waveforms, the optical sensor comprising an emitter module (1) and a light receiver module (4) housed in kinematically connected housings (3, 5), wherein the output of the light receiver module (4) is an output of a sensor 6) for positioning the light receiver module (4) relative to the emitter module (1), said member (6) comprising a resilient element (7) connected to both the emitter module (1) and the light receiver module (4) and allowing the light receiver module (4) (1) at the same time as positioning it against a person's skin surface; characterized in that the outer shape of the surface of the emitter holder (2) is formed against the inner surface of the lower part of a person's ear, wherein the emitter holder (2) is made of opaque resilient material and wherein the positioning member includes a linear guide (6) an axial axis connecting the emitter (1) and the light receiver (49 while securing the coaxial position of the emitter (1) and the light receiver (4). Optical sensor for human pulse waveforms according to Claim 1, characterized in that the emitter (1) comprises two radiation sources and the wavelengths λΐ and Λ2 are selected to be in the spectral regions λΐ = (640-720) nm and Λ2 = (960-1040) nm. .