KR200493275Y1 - Optical sensor of human pulse waveform - Google Patents

Abstract

This utility model relates to medicine, particularly functional diagnosis of human conditions, and can be used to perform medical tests, including examining hemodynamics, and to systems for monitoring the degree of fatigue of driving a personal vehicle. The optical sensor of the human pulse waveform positions the optical receiver module with respect to the emitter module using an emitter module and an optical receiver module provided in a kinematically connected housing, and an elastic element that is simultaneously connected to the emitter module and the optical receiver module. Comprising means for setting, and for moving the optical receiver module relative to the emitter while ensuring the position of the emitter and the optical receiver by contacting the skin surface of the person; The outer shape of the emitter holder surface is made to be in contact with the inner surface of the lower part of the auricle of the person, the emitter holder is made of an opaque elastic material, the positioning means comprises a linear guide, the axis of which is the emitter and It is parallel to the optical axis connecting the optical receiver.

Description

Optical sensor of human pulse waveform

This utility model relates to the functional diagnosis of medicine, especially the human condition, can be used to perform medical tests, including investigating hemodynamics, and also to systems for monitoring the degree of fatigue of driving a personal vehicle. I can.

Pulse waveforms generated by blood passing through human arteries convey information about the state of the human cardiovascular system. This information is important for predicting the impact of adverse environmental factors on the human body's ability to adapt. One of the most widely used methods of registering pulse waveforms is sphygmography. This method uses a sensor placed on a person's skin in the area just above the artery. Pulse waveforms are recorded using mechanical or optical methods based on sensor movement due to an increase in arterial volume under the skin.

The pressure sensor (RU2430344, G01L 9/08, publication date 2011.09.27, publication 27) is a disk-shaped quartz piezoelectric mounted on the surface of a body, a circular metal membrane, a crystal holder parallel to the membrane with a gap between the cell and the membrane. A metal base comprising a cell, wherein a center point of the disk-shaped piezoelectric cell and the membrane is aligned with a longitudinal axis of the crystal holder, and includes a circular electrode provided on the surface of the piezoelectric cell at the center point thereof, a bottom portion, an inner protrusion, and an inner groove, A metal support ring having an outer diameter equal to the outer diameter of the membrane, a rivet having a flat cylindrical head, an elastic flat member having a central opening having a rivet therethrough, an adjusting screw having a spherical end, the adjusting screw Screwed coaxially with the screw hole in the center of the bottom portion of the metal base, the spherical end contacting the flat surface of the rivet head, along the circumference between the inner protrusion of the base and the inner surface of the support ring Forming a fixed connection between the firmly fixed elastic member and the crystal holder, the lower surface of the support ring supports the metal membrane, and the outer cylindrical surface of the support ring is inwardly fitted with the surface of the inner groove of the base. Coupled, the surface is limited in depth at the bottom portion of the latter by the inner protrusion, the upper and lower surfaces of the support ring and the base protrusion surface are parallel to the crystal holder surface, and the disk-shaped quartz piezoelectric cell is flat And, a circular electrode is characterized in that it is provided on the surface of the piezoelectric cell facing the membrane. The sensor comprises a first pneumatic channel formed by a pneumatic filter and a reactor choke in communication with each other and formed separately by a vertical cylindrical channel in the inner wall of the base filled with a filter material such as felt. And, the reactor choke is formed by a horizontal cylindrical channel having a small diameter, and comprises a second pneumatic channel formed by a vertical cylindrical channel at the sidewall of the base, the channel portion being filled with filter material, and spring-loaded A horizontal cylindrical channel having a compensating valve is formed by a cylinder having a ring groove along its surface and a pressure cap, the channels communicate with each other, wherein the inlet of the pneumatic filter and the inlet of the second pneumatic channel are The inlet opening is connected to each other, the reactor choke outlet and the outlet of the second pneumatic channel are connected to each other with the volume defined by the wall, the bottom portion of the base and the inner membrane surface, and the volume is a compensation valve when the sensor returns to the initial position. By means of a second pneumatic channel, it is characterized in that they are connected to each other with the inlet opening of the main body. Piezoelectric sensors are used in pulse wave recording tests using an occlusive cuff placed over the forearm.

In addition to contact sensors, contactless pulse wave sensors are also known in the art. The publication (DA Usanov, AV Skripal, EO Kaschavtsev, "Determining Pulse Waveform Based on a Semiconductor Laser Autodyne Signal", Letters to Technical Physics Journal, 2013, vol. 39, B.5, pp 82-87) discloses diffraction-87. A semiconductor laser autodyne comprising a laser diode of a quantum-sized InGaAlP structure with a limiting single space mode and a radiation wavelength of 654 nm, a stabilized current source to power the laser, and a photodetector to measure the power generation of the laser. It is a sensor formed by (autodyne). When performing a blood pressure test using the sensor, the laser radiation should be directed to the skin surface in the wrist area where the radial artery is closer to the skin surface. Some of the radiation reflected from the skin surface goes back to the laser resonator and changes the laser power generation as the pulse wave passes through the artery. Changes in laser power generation are recorded using a photo detector, and its output signal is sent to a data processing and storage system.

Disadvantages of the above prior art devices include structural complexity and incompatibility for wearable use during long-term cardiovascular system monitoring sessions, in particular for on-duty monitoring of vehicle drivers.

A number of sensors are known in the art that are used to monitor physiological parameters of the human cardiovascular system, including measuring blood oxygen concentration; These sensors are structurally simple and wearable. Such a sensor is disclosed, for example, in the following patents: US Pat. No. 7223396, A61B 5/00, published Aug. 28, 2007; U.S. Patent No. 8532729, A61B 5/1455, published Sep. 10, 2013; U.S. Patent No. 858888, A61B 5/1455, published on November 19, 2013. Structurally, such a sensor is an earclip configured to be mechanically attached to the human body in the ear region, mainly in the earlobe. Such sensors, including a radiation source and an optical receiver, can measure the optical transmission of blood vessel-rich biological tissues and record blood oxygen concentrations.

The prior art solution for the utility model of the present invention is a wearable biometric sensor comprising an emitter module and an optical receiver module located in a kinematically connected housing (US Patent No. 8219532, A61B, published on July 24, 2012). 5/1455), wherein the output of the optical receiver module is the output of the sensor, the sensor further comprising means for locating the optical receiver module relative to the emitter module, the means comprising the emitter module and the optical receiver module It is connected to both and includes a resilient element for changing the optical receiver module with respect to the emitter module while securing its position by contacting the human skin surface in the auricle region.

The main drawback of the prior art solution is its low accuracy in recording the pulse wave form.

Despite the perception of its simplicity in construction, the wearable oximetry sensor is a full-fledged device that performs the most complex diagnostic tasks. The patient's health (and in some cases their longevity) depends on the accuracy of these sensor readings. The specificity of using a variety of devices to perform non-invasive diagnostic methods for assessing the proportion of coral hemoglobin in the blood is D.A. Rogatkin, "Physical basics of optical oxymetry", Medical Physics, 2012, issue 2, pp. It is described in detail in 97-114. The technical requirements for the development and production of optical oxymeters are described in the International Standard Publication ISO 9919:2011, Medical Electrical Equipment - Specific requirements for the basic safety and essential performance of medical pulse oximetry equipment.

Due to the high accuracy requirements of blood pressure measurement and oxygen metric measurement measured by a wearable optical pulse wave sensor, security inconvenience attached to the body of a monitored person while wearing the device for a long time in a wide range of climatic conditions and external lighting conditions. A number of requirements can be summarized as follows with minimal effort:

· The sensor structure should be capable of attaching to a body part that does not accidentally come into contact with clothing while increasing the concentration of capillaries as much as possible;

· Attaching the sensor to the body should be as safe as possible without inadvertent movement due to human movement, and it should be possible to avoid some discomfort due to obstruction or obstruction of blood circulation in the main surface in the attachment area. Sensor weight should be minimized;

· The sensor structure should eliminate or reduce the effects of optical receiver exposure by external sources as much as possible, and should provide a signal to noise ratio as high as possible;

Means for fixing the sensor to the human body should be provided to adapt the emitter and receiver positions to the individual physiological specifics of the subject being investigated without changing device calibration parameter parameters or data analysis methods for the received data.

The purpose of this utility model is to improve the accuracy of recording pulse waveforms and measuring human hemodynamic parameters by achieving technical results for increasing the signal-to-noise ratio value.

The disclosed technical results are achieved by an optical sensor of a human pulse wave, the optical sensor comprising an emitter module and a photoreceiver module provided in a kinematically connected housing, the optical receiver module The output is the output of the sensor, the optical sensor further comprising means for positioning an optical receiver module relative to the emitter module, the means being connected to both the emitter module and the optical receiver module. And a resilient element allowing movement of the optical receiver module relative to the emitter module while securing its position by contacting the human skin surface; The outer shape of the emitter holder surface is configured to contact the inner surface of the lower part of the auricle of the person and the intertragic notch between them, the emitter holder is made of an opaque elastic material, and the positioning means is the And a linear guide having an axis extending parallel to an optical axis of the emitter and the optical receiver, ensuring a coaxial position of the emitter and the optical receiver.

Further, the optical sensor emitter may include two radiation sources having λ1 and λ2 radiation wavelengths selected within a spectral range of λ1=(640-720) nm and λ2=(960-1040) nm.

The analysis of human pulse waveforms (sphygmogram) is not only for the general physiological state of a person, but especially for the state of the cardiovascular system, i.e. the flow of blood to the capillaries, the tone and elasticity of the vessels, the volume expansion of the vessels, Provide evidence of wall elasticity and myocardial contractile function. Irradiating the pulse waveform using an optical light transmittance sensor involves measuring the attenuation of radiation by blood-filled tissues over various spectral ranges. This process involves simultaneously recording changes in blood vessel volume during pulse waves (pulse curve waveforms) and blood oxyhemoglobin concentration (differential transmission at various wavelengths). It should be noted that while hemodynamics is determined only by the pulse curve waveform, blood oxygenation affects the waveform amplitude assuming that the oxygen content in the blood is generally constant during a single pulse wave period. The accuracy of the measured hemodynamic properties and sensor performance generally depend on the sensor structure and the level of compliance with essential requirements for attachment to the human body.

The structure of the disclosed utility model includes a plurality of novel technical solutions (claimed features), the combination of which achieves the claimed technical results, and the features include:

1) The outer shape of the emitter holder surface is configured to abut the inner surface of the lower part of the auricle of the person in the area defined by the tragus and antitragus. This allows the sensor to be safely attached to the human body in areas that do not indirectly contact clothing, but includes a sufficiently dense capillary net. In contrast to the prior art sensor applied to be fixed to the earlobe, the structure of this utility model provides attachment to the cartilage part of the ear wheel, eliminating possible discomfort (paralysis) due to extended wearing of the sensor, and the sensor-equipped area In the auricle tissue, it provides a higher level and quality of the output sensor signal due to the high blood vessel density and diameter. In addition, the center of gravity of the sensor is provided between the optical axis of the sensor and the positioning means guide. This arrangement can minimize the effect on the output sensor signal and twisting torque while wearing (minimizing the level of noise caused by natural head movements) while attracting the aesthetic gaze of the sensor being worn, which is particularly important for women.

2) To prevent ambient exposure of the sensor light receiver caused by radiation from an external source, the emitter has an outer surface of the emitter that contacts the inner surface of the lower part of the human auricle and outlines the outer surface of the auricle. An opaque holder is provided. The holder reduces the exposure level of the optical receiver under variable lighting conditions, and reduces the pressure on the auricle surface so that it can be worn more comfortably for a longer period of time.

3) The sensor structure provides for individual-specific adjustments in the relative positioning of the emitter and optical receiver modules while maintaining the orientation of the emitter and optical receiver modules using a linear guide.

The utility model is described with reference to the accompanying drawings.
1 is an overall view of the disclosed sensor.
2 is a cross-sectional view of the sensor structure.
3 is a schematic diagram of a human ear showing the attachment position of the sensor.
Fig. 4 shows the results of a comparative test of the disclosed sensor and the prior art sensor, the results verifying the validity of the claimed technical results.
2 includes the following reference numbers: emitter 1; Emitter holder 2; Emitter module housing (3); Optical receiver 4; Optical receiver module housing 5; Linear guide 6; And spring (7).
3 includes the following reference numbers: ear beads 8; Face beads (9); Indentation 10 between ear beads (a shaded area corresponding to the area adjacent to the earway to the emitter holder 2 of the sensor initiated); And the earlobe (11).

The disclosed sensor comprises an emitter (1) mounted in a holder (2) and arranged in an emitter (1) module housing (3) and an optical receiver (4) mounted in a holder and arranged in a module housing (4) Includes. The emitter 1 includes a red LED and an ultraviolet LED that respectively emit radiation in the spectral range of (640-720) nm and (960-1040) nm, and the extinction coefficient of oxyhemoglobin and deoxyhemoglobin ( It is known that extinction coefficients) differ most significantly in this range. The housings 3 and 5 of the emitter 1 module and the optical receiver 4 module are each made of a light and durable plastic material, for example polycarbonate. The structure of the sensor disclosed is according to a linear guide 6 having an axis parallel to the optical axis of the device connecting the emitter 1 and the sensing element of the optical receiver 4 to the optical receiver 4 module housing ( 5) enables a linear movement of the emitter (1) module housing (3). Linear springs 7 symmetrically mounted on both sides of the linear guide 6 provide a "attraction" force, and the ejector 1 is in any position by the action of the linear guide 6 It faces in the direction of the optical receiver 4. The holder 2 of the emitter 1 is made of an elastically opaque material, for example silicon carbide. This embodiment of the holder prevents exposure of the optical receiver 4 to the surroundings.

4 shows two graphs showing the waveforms of one patient being examined, and data received from two sensors having the same optical/electronic structure but different structures. The lower graph represents the pulse wave waveform received from the conventional sensor output, and the upper graph represents the waveform received using the claimed sensor. Also, the enlarged view shows the two graph regions at the local maximum. Analysis of the pulse waveform shows that the signal-to-noise ratio for this utility model exceeds the signal-to-noise ratio of the prior art sensor by about 30 dB. This increased quality provides an increase in the accuracy of recording hemodynamic parameters in humans. The enlarged area (view A) clearly shows the pulse wave characteristics in the local maximum area, but in the prior art waveform (view B) this characteristic is completely obscured by noise.

Thus, the optical sensor of the disclosed human pulse waveform includes a combination of features that achieves a technical result of increasing measurement accuracy due to an increase in the signal-to-noise ratio value.

Claims (2)

As an optical sensor of a human pulse wave, the optical sensor includes an emitter module and an optical receiver module provided in a kinematically connected housing, and an output of the optical receiver module is an output of the sensor,
The optical sensor further comprises means for positioning the optical receiver module relative to the emitter module,
The means is connected to both the emitter module and the optical receiver module, and comprises an elastic element for moving the optical receiver module relative to the emitter module while securing the position of the emitter module and the optical receiver module by contacting the human skin surface Including;
The outer shape of the emitter holder surface is configured to be in contact with the inner surface of the lower part of the auricle of a person,
The emitter holder is made of an opaque elastic material,
The positioning means comprises a linear guide having an axis extending parallel to an optical axis connecting the emitter and the optical receiver while ensuring a coaxial position of the emitter and the optical receiver during movement of the emitter with respect to the optical receiver. Optical sensor of human pulse waveform. The human pulse waveform of claim 1, wherein the emitter comprises two sources of radiation, and the radiation wavelengths λ1 and λ2 are selected to be within a spectral range of λ1=(640-720) nm and λ2=(960-1040) nm. Optical sensor.

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