Miniature optical fiber probe for pilot health monitoring

Abstract

The utility model belongs to the field of photoelectric sensing, and relates to a miniature optical fiber probe for pilot health monitoring, which comprises two infrared light emitting diodes, a photodiode, a conduction optical fiber, an optical fiber probe, a diode driving circuit and a signal processing circuit, one ends of the two infrared light-emitting diodes and the photodiode are connected with the optical fiber probe through conduction optical fibers; the two infrared light emitting diodes are also connected with a diode driving circuit; the photodiode is connected with the signal processing circuit; the infrared light-emitting diode serves as a light source, light signals emitted by the infrared light-emitting diode are coupled into the optical fiber and emitted to the surface of detected skin at the position of the optical fiber probe, and red light and infrared light reflected by the surface of the skin contain blood oxygen and heart rate information, are collected by the optical fiber probe, are coupled to the photodiode through the conduction optical fiber and are converted into electric signals. And the signal processing circuit at the rear end is used for resolving the heart rate and the blood oxygen.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the photoelectric sensing field relates to a kind of micro optical fiber probe for pilot health monitoring. BACKGROUND

[0002] In recent years, with the development of aviation industry, higher requirements are put forward for the health of pilots. Monitoring the heart rate and blood oxygen of pilots during flight, obtaining the vital signs of pilots, is the key to ensure the safety of pilots and aircraft flight, which helps to discover the risks such as cabin decompression hypoxia in time and understand the stress response in different stages of flight.

[0003] The traditional monitoring method of heart rate and blood oxygen saturation is contact measurement, such as piezoelectric sensor, blood oxygen clamp, etc. These methods need to be attached to wrist or finger when extracting signals, which affects the normal work of pilots, and cannot work normally in extreme environment. In addition, contact measurement causes inaccurate measurement when sensor moves during maneuvering flight. Non-contact measurement methods include camera, millimeter wave radar and photoelectric detection. Camera has large volume and is greatly affected by environmental light. Millimeter wave radar has large loss in signal transmission process and is easily affected by electromagnetic interference. SUMMARY

[0004] The utility model discloses a kind of micro optical fiber probe for pilot health monitoring, which realizes non-contact, non-destructive, non-invasive, light quality, small volume and does not affect human comfort during measurement.

[0005] The technical solution of the utility model:

[0006] A kind of micro optical fiber probe for pilot health monitoring, comprising: two infrared light-emitting diodes, photodiode, conducting optical fiber, optical fiber probe, diode drive circuit and signal processing circuit;

[0007] Two infrared light-emitting diodes and photodiode are connected to optical fiber probe by conducting optical fiber at one end;

[0008] Two infrared light-emitting diodes are also connected to diode drive circuit;

[0009] Photodiode is connected to signal processing circuit;

[0010] Infrared light-emitting diode as light source, the light signal emitted is coupled into optical fiber, and is emitted to the skin surface to be measured at optical fiber probe, the red light and infrared light reflected by skin surface contain blood oxygen and heart rate information, which is collected by optical fiber probe, coupled to photodiode by conducting optical fiber, converted into electrical signal, and heart rate and blood oxygen are calculated in rear-end signal processing circuit.

[0011] Further, the light emitting bands of the two infrared light emitting diodes are 660 nm and 880 nm respectively.

[0012] Further, the three diodes are coupled with the conducting optical fiber through the lenticular lens.

[0013] The distance between the end face of the conducting optical fiber and the light emitting face or receiving face of the diode and the neutral plane of the lenticular lens is equal to the focal length f.

[0014] Further, the optical fiber probe is a rectangular optical fiber end face, and the three conducting optical fibers are fused on the rectangular optical fiber end face.

[0015] Further, the photodiode is fused in the middle of the rectangular optical fiber end face, and the two infrared light emitting diodes are fused at the two ends of the rectangular optical fiber end face.

[0016] Further, the rectangular end face of the fused photodiode is larger than the rectangular end face of a single infrared light emitting diode.

[0017] Advantages

[0018] Aiming at the health monitoring of pilots, a micro optical fiber probe is proposed. The probe uses PPG method to measure the heart rate and blood oxygen saturation of the human body, realizing the advantages of non-contact, non-invasive, small volume, light weight, anti-electromagnetic interference, high comfort, and not affected by the external environment.

[0019] Optoelectronic detection technology has the advantages of anti-electromagnetic interference, strong insulation, non-invasive detection, and has a wide application in the field of human health monitoring.

[0020] In the process of human blood circulation, when blood flows through blood vessels, under the regular beating of the heart, the blood volume will also show pulsatile changes. Blood and muscle tissue have absorption effect on light signals, among which the amount of light absorbed by tissue and muscle is constant, so the change of light intensity can reflect the change of blood vessel volume. This method is called photoplethysmography (PPG). In order to realize the monitoring of the heart rate and blood oxygen saturation of pilots during flight, the photoplethysmography method is combined with optical fiber sensing, which reduces the structure of the sensor probe and improves the adaptability of installation. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic diagram of an optical fiber probe for heart rate and blood oxygen saturation measurement;

[0022] Among them, 1: optical fiber probe, 2: conducting optical fiber, 3: red light emitting diode, 4: photodiode, 5: infrared light emitting diode, 6: diode driving circuit, 7: signal processing circuit.

[0023] Figure 2 is a schematic diagram of the coupling structure of the diode and the conducting optical fiber;

[0024] Wherein 2: conductive optical fiber, 8: miniature lenticular lens, 3: red light emitting diode, 4: photodiode, 5: infrared light emitting diode.

[0025] Figure 3 It is the structural schematic diagram of optical fiber probe;

[0026] Wherein 9: the rectangular end face corresponding to the red light emitting diode, 10: the rectangular end face corresponding to the photodiode, 11: the rectangular end face corresponding to the infrared light emitting diode. DETAILED DESCRIPTION

[0027] A miniature optical fiber probe sensor for pilot health monitoring, the utility model discloses the following technical scheme realizes:

[0028] The sensor structure is as shown in Figure 1 . The sensor uses red light diode (660nm) and infrared light diode (880nm) as light source, and the light signal emitted by the diode is coupled into the optical fiber, and is emitted at the optical fiber probe, and is irradiated to the measured skin surface. According to the photoelectric volume principle, the oxygenated hemoglobin and deoxygenated hemoglobin in the blood have different absorption coefficients for 660nm light and 880nm light, so that the blood oxygen can be obtained;The pulse beat filling volume change can influence the light absorption rate, so that the heart rate can be obtained.

[0029] The red light and infrared light reflected by the skin surface contain the information of blood oxygen and heart rate, are collected by the optical fiber probe, are coupled to the photodiode through the conductive optical fiber, and are converted into electric signals. The rear-end signal processing circuit realizes the calculation of heart rate and blood oxygen.

[0030] In order to realize the high-efficiency coupling of the optical fiber and the diode, reduce the loss of the light signal in the propagation process, the coupling device is as shown in Figure 2 . The light signal emitted by the diode is focused on the optical fiber end face by the miniature convex lens, the optical fiber end face is kept flat, and the distance between the diode and the convex lens and the distance between the convex lens and the optical fiber end face should be the focal length f of the convex lens, so as to ensure the effective transmission of the light signal.

[0031] In order to ensure the receiving efficiency of the skin reflected light, the end face area of the optical fiber coupled with the photodiode should be increased at the optical fiber probe, and the specific structure is as shown in Figure 3 . The three optical fibers should be fused with rectangular optical fiber end faces at the end close to the measured skin, so as to reduce the escape of the light signal. Among them, the rectangular end face corresponding to the photodiode should be larger than the rectangular end face corresponding to the light emitting diode, and the rectangular end face corresponding to the photodiode is in the middle, and the rectangular end faces corresponding to the two light emitting diodes are on both sides.

[0032] The optical fiber probe is installed on the helmet of the pilot, which does not affect the normal work of the pilot and also ensures the comfort.

[0033] Heart rate and blood oxygen saturation are two important indicators for evaluating the health of pilots. Obtaining real-time heart rate and blood oxygen saturation information is the key to observing the vital signs of pilots and ensuring the safety of pilots and aircraft. Photoelectric sensing technology has the advantages of anti-electromagnetic interference and non-invasive measurement, and has been widely used in heart rate monitoring. In order to realize the miniaturization of the sensor and improve the anti-interference ability, a micro optical fiber probe for monitoring the health of pilots is designed.

[0034] Firstly, the diode is coupled with the conductive optical fiber. The utility model uses 660nm and 880nm light emitting diodes and corresponding waveband photodiodes, the focal length of the micro convex lens is f, the distance between the diode and the micro convex lens and the distance between the micro convex lens and the end face of the optical fiber are both f, and after being fixed, the diode is packaged.

[0035] Secondly, the conductive optical fiber is fused with the end face of the optical fiber. The diode is fused with the corresponding rectangular end face, and then the rectangular end faces are adhered together according to the positions.

[0036] Thirdly, the corresponding diode driving current and signal processing circuit are designed, and the sensor structure is built.

[0037] Fourthly, the optical fiber probe is installed on the inner side of the helmet, and the front end of the probe is packaged with transparent material.

Claims

1. A miniature fiber optic probe for pilot health monitoring, characterized in that the probe... include: Two infrared LEDs, a photodiode, a fiber optic cable, a fiber optic probe, a diode driver circuit, and a signal processing circuit; Two infrared light-emitting diodes and a photodiode are connected to the fiber optic probe at one end via a conductive fiber optic cable; The two infrared LEDs are also connected to a diode driver circuit; The photodiode is connected to the signal processing circuit. An infrared light-emitting diode serves as the light source, emitting a light signal that is coupled into an optical fiber. The signal is then emitted at the optical fiber probe and projected onto the surface of the skin being tested. The red and infrared light reflected back from the skin surface contains information about blood oxygenation and heart rate, which is collected by the optical fiber probe, coupled to a photodiode via a transmission optical fiber, and converted into an electrical signal. The heart rate and blood oxygenation are then calculated in the signal processing circuit at the back end.

2. The miniature fiber optic probe according to claim 1, characterized in that: The two infrared LEDs emit light at wavelengths of 660nm and 880nm, respectively.

3. The miniature fiber optic probe according to claim 1, characterized in that, All three diodes are coupled to the optical fiber through a biconvex lens; The distance between the end face of the optical fiber and the light-emitting or receiving surface of the diode and the neutral plane of the biconvex lens is equal to the focal length f.

4. The miniature fiber optic probe according to claim 1, characterized in that, The fiber optic probe has a rectangular fiber end face, with three conductive fibers fused together on the rectangular fiber end face.

5. The miniature fiber optic probe according to claim 4, characterized in that, A photodiode is fused to the middle of the rectangular fiber end face, and two infrared LEDs are fused to both ends of the rectangular fiber end face.

6. The miniature fiber optic probe according to claim 5, characterized in that, The rectangular end face of the photodiode fusion is larger than the rectangular end face of a single infrared LED.

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