CN114441461B - Proximity sense-contact sense sensor based on micro-nano optical fiber - Google Patents
Proximity sense-contact sense sensor based on micro-nano optical fiber Download PDFInfo
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- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
- G01L1/242—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet the material being an optical fibre
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Abstract
The invention discloses a proximity-contact sensor based on micro-nano optical fibers. The flexible substrate, the isolation layer and the flexible film are sequentially laminated, one micro-nano optical fiber is respectively arranged between the flexible substrate and the isolation layer and between the isolation layer and the flexible film, and the two micro-nano optical fibers are arranged in parallel along a straight line and are arranged right above and below; the two micro-nano optical fibers are respectively used for sensing proximity sense and sensing contact sense, the micro-nano optical fiber for sensing proximity sense is positioned above, a humidity sensitive layer is arranged on the micro-nano optical fiber for sensing proximity sense, and a humidity and pressure working window is formed in a flexible film above the humidity sensitive layer. The invention can realize the whole process monitoring of approaching, contacting, leaving and the like, and provides a new feasibility design scheme for the application of the multifunctional photon skin in the aspects of man-machine interaction and intelligent robots.
Description
Technical Field
The invention belongs to a touch sensor in the field of touch perception, and particularly relates to a proximity sense-contact sense sensor based on micro-nano optical fibers.
Background
The human body touch sense is the touch sense realized by effectively fusing various stimulus signals in the brain through the transmission of nerves after mechanoreceptors in the skin respond to different external stimuli. The tactile physiology of the human body, including mechanoreceptors, neural coding schemes and grabbing strategies, inspires scientists to design human-computer interaction systems.
Currently, electronic skin has evolved from detecting single functions to detecting complex variables simultaneously. Currently, electrical sensors based on resistive, capacitive, inductive, etc. strategies have been used to detect pressure, temperature, proximity, vibration, etc. With the urgent need for sensitive perception, collaborative monitoring of proximity-contact events has attracted extensive research interest in the field of haptic perception. For example: the nano energy institute Wang Zhonglin teaching subject group of the Chinese academy developed a highly scalable matrix network to expand the sensing function of electronic skin to temperature, in-plane strain, humidity, light, magnetic field, pressure and proximity. The professor of Zhengzhou university instead of kun and the professor Pan Caofeng of the national institute of science nano energy source cooperate to develop a multifunctional electronic skin for ultrasensitive contact and non-contact sensing with adjustable strain detection range using multi-layered silver nanowires/reduced graphene oxide/thermoplastic polyurethane films.
Compared with an electrical sensor, the optical fiber sensor based on optics has the advantages of small volume, electromagnetic interference resistance, high sensitivity, high response speed and the like. Recently, a group of professor subjects, university of south Beijing Xu Fei, reported a Polydimethylsiloxane (PDMS) embedded hybrid plasma micro-nano fiber resonator based wearable device for highly sensitive pressure sensing. The sensing of pressure, strain, bending angle and temperature is realized by using the PDMS embedded micro-nano optical fiber. Although a multifunctional tactile sensation research based on the optical principle has made important progress, a cooperative sensation research for proximity-touch sensation is still lacking.
Disclosure of Invention
In order to solve the problems in the background art, the invention aims to provide a proximity sense-contact sense sensor based on micro-nano optical fibers, which can realize cooperative measurement of proximity sense and contact sense.
The invention relates to a flexible optical touch sensor with skin structure and functional characteristics, which has important significance in the fields of man-machine interaction and health care.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
the flexible substrate, the isolation layer and the flexible film are sequentially laminated, a first micro-nano optical fiber is arranged between the flexible substrate and the isolation layer, a second micro-nano optical fiber is arranged between the isolation layer and the flexible film, the two micro-nano optical fibers are all arranged in parallel along a straight line, and the second micro-nano optical fiber is positioned right above the first micro-nano optical fiber.
Both micro-nano optical fibers include an unstretched portion at both ends, a middle waist region, and a tapered transition region connected between the unstretched portion at both ends and the middle waist region.
The two micro-nano optical fibers are respectively a micro-nano optical fiber for sensing proximity sense and a micro-nano optical fiber for sensing contact sense, the micro-nano optical fiber for sensing contact sense is positioned between the flexible substrate and the isolation layer, and the micro-nano optical fiber for sensing proximity sense is positioned between the isolation layer and the flexible film.
A humidity sensitive layer is arranged on the micro-nano optical fiber for sensing proximity between the isolation layer and the flexible film, and a humidity and pressure working window is arranged at the flexible film above the humidity sensitive layer.
The waist region of the micro-nano optical fiber for sensing proximity sense is positioned right above the waist region of the micro-nano optical fiber for sensing contact sense, and the humidity sensitive layer is arranged above the waist region of the micro-nano optical fiber for sensing proximity sense.
The waist diameters of the two micro-nano optical fibers are different, and the waist diameter of the micro-nano optical fiber for sensing the proximity sense is smaller than that of the micro-nano optical fiber for sensing the contact sense.
And two ends of the two micro-nano optical fibers are respectively connected with a white light source and a spectrometer.
The flexible substrate, the isolation layer and the flexible film are made of the same material, and the refractive index of the flexible substrate, the isolation layer and the flexible film is larger than that of air, but smaller than that of the micro-nano optical fiber.
Besides being sensitive to humidity, the refractive index of the humidity sensitive layer material needs to be larger than that of air and smaller than that of the micro-nano optical fiber.
The structure of the invention is sequentially provided with a proximity sensing unit and a contact sensing unit from top to bottom. The proximity sense and contact sense sensing units are respectively realized by sensing humidity and pressure. The proximity sensing unit is composed of one micro-nano optical fiber, a flexible substrate, a humidity sensitive layer and a humidity sensing window, and the proximity sensing unit is composed of the other micro-nano optical fiber and the flexible substrate.
The proximity-contact sensor can realize the whole process monitoring of proximity, contact, departure and the like, and provides a new feasibility design scheme for the application of the multifunctional photon skin in the aspects of man-machine interaction and intelligent robots.
Compared with the prior art, the invention has the beneficial effects that:
(1) The proximity-contact sensor based on the optical principle has the characteristics of electromagnetic interference resistance, high response speed, high sensitivity and the like.
(2) The proximity sense-contact sense isolation layer can completely avoid crosstalk of proximity sense and contact sense signals.
(3) The invention can completely distinguish the full contact event processes of approaching, contacting, leaving and the like, and can distinguish the events of fingers with fingerstall, bare fingers and the like.
(4) The micro-nano optical fiber proximity-contact sensor has great practical value in the fields of man-machine interaction, health care and the like.
Drawings
FIG. 1 is a schematic diagram of the structure of the micro-nano optical fiber proximity-contact sensor of the present invention in use;
FIG. 2 is a spectrum diagram of the micro-nano optical fiber proximity sensing unit under different humidity;
FIG. 3 is a graph showing the relationship between humidity and 620nm light transmittance of a micro-nano fiber proximity sensor according to the present invention;
FIG. 4 is a response time curve of a micro-nano fiber proximity sensor of the present invention;
FIG. 5 is a spectral graph of the transmittance of the micro-nano optical fiber touch sensor according to the present invention as a function of pressure;
FIG. 6 is a graph of transmittance of the micro-nano fiber optic touch sensor of the present invention at multiple wavelengths at different pressures;
FIG. 7 is a graph of the transmittance of the micro-nano fiber proximity-touch sensor of the present invention in various events.
In the figure: 1-flexible substrate, 2-unstretched part, 3-tapering transition zone, 4-waist region of micro-nano optical fiber for sensing touch, 5-isolation layer, 6-waist region of micro-nano optical fiber for sensing proximity, 7-flexible film, 8-humidity sensitive layer, 9-humidity and pressure working window, 10-white light source, 11-spectrometer, 12-white light source, 13-spectrometer, 14-humidity testing device for applying humidity, 15-mechanical testing device for applying pressure.
Detailed Description
The invention is further described below with reference to the drawings and the detailed description.
As shown in fig. 1, the implementation of the invention comprises a flexible substrate 1 for placing micro-nano optical fibers for sensing touch, two stretched micro-nano optical fibers, an isolation layer 5 for isolating proximity-touch signals, a flexible film 7 for covering the micro-nano optical fibers for sensing proximity and a humidity sensitive layer 8, wherein the flexible substrate 1, the isolation layer 5 and the flexible film 7 are sequentially laminated, a first micro-nano optical fiber is arranged between the flexible substrate 1 and the isolation layer 5, a second micro-nano optical fiber is arranged between the isolation layer 5 and the flexible film 7, the isolation layer 5 is used for isolating the two micro-nano optical fibers for sensing proximity and touch, and the two micro-nano optical fibers are arranged in parallel along a straight line and are positioned right above the first micro-nano optical fiber.
Both micro-nano optical fibers comprise an unstretched part 2 at both ends, a middle waist region, and a tapered transition region 3 connected between the unstretched part 2 at both ends and the middle waist region. The diameter of the waist region is smaller than that of the unstretched parts 2 at the two ends, and the periphery of the tapering transition region 3 is a conical surface for transitional connection of the unstretched parts 2 and the different diameters of the waist region.
In a specific implementation, the two drawn micro-nano optical fibers are formed after being drawn and prepared.
The micro-nano optical fibers for sensing the proximity sense and the contact sense are layered and attached to the flexible substrate in a linear mode, the sensing unit of the proximity sense is arranged on the upper layer of the sensor, and the sensing unit of the contact sense is arranged on the lower layer of the sensor.
The two micro-nano optical fibers are respectively a micro-nano optical fiber for sensing proximity sense and a micro-nano optical fiber for sensing contact sense, the micro-nano optical fiber for sensing contact sense is positioned between the flexible substrate 1 and the isolation layer 5, and the micro-nano optical fiber for sensing proximity sense is positioned between the isolation layer 5 and the flexible film 7.
The tapered transition region of the micro-nano optical fiber, the waist region of the micro-nano optical fiber and the part of the un-tapered part are arranged on the flexible substrate and are embedded by the flexible film. And an isolating layer 5 is covered between the micro-nano optical fiber for sensing proximity sense and the micro-nano optical fiber for sensing contact sense, and the micro-nano optical fiber contact sense unit is embedded and the proximity-contact sense sensing signal is isolated.
A humidity sensitive layer 8 is arranged on the micro-nano optical fiber for sensing proximity between the isolation layer 5 and the flexible film 7, a humidity and pressure working window 9 is arranged at the flexible film 7 above the humidity sensitive layer 8, and external humidity is contacted with the humidity sensitive layer 8 through the humidity and pressure working window 9.
In a specific implementation, the humidity and pressure working window 9 is an annular structure with through holes.
The waist region of the micro-nano optical fiber for sensing proximity is positioned right above the waist region of the micro-nano optical fiber for sensing contact, and the humidity sensitive layer 8 is arranged above the waist region of the micro-nano optical fiber for sensing proximity.
In the implementation, a micro-nano optical fiber for sensing proximity is placed on the isolation layer 5, a thin film 7 with small holes is covered on the micro-nano optical fiber for sensing proximity, and a sensitive material 8 for sensing proximity is covered in the small holes of the thin film 7.
The diameters of the waist regions of the two micro-nano optical fibers are different, the diameter of the waist region 6 of the micro-nano optical fiber for sensing proximity sense is smaller than the diameter of the waist region 4 of the micro-nano optical fiber for sensing contact sense, namely the waist region 4 of the micro-nano optical fiber for sensing contact sense is larger than the waist region 6 of the micro-nano optical fiber for sensing proximity sense. Preferably, the waist diameter of the micro-nano optical fiber for sensing the proximity sense is 1.3 μm, and the waist diameter of the micro-nano optical fiber for sensing the contact sense is 2 μm.
Two ends of the two micro-nano optical fibers are respectively connected with a white light source and a spectrometer. Specifically, the device comprises two white light sources and two spectrometers, wherein one white light source 10 and one spectrometer 11 are respectively connected with two ends of the proximity sensing unit, and the other white light source 12 and the spectrometer 13 are respectively connected with two ends of the contact sensing unit.
The two ends of the micro-nano optical fiber for sensing proximity are respectively connected with the white light source 10 and the spectrometer 11, the white light source 10 emits light beams, and the light beams are transmitted by the micro-nano optical fiber for sensing proximity and then are input into the spectrometer 11; the two ends of the micro-nano optical fiber for sensing the touch are respectively connected with the white light source 12 and the spectrometer 13, and the white light source 12 emits light beams which are transmitted by the micro-nano optical fiber and then input into the spectrometer 13.
The micro-nano optical fiber is based on SiO 2 Single mode fiber of the material (Corning, size 9/125 μm).
The thickness of the isolation layer 5 isolating the proximity-touch sensing signal is such that there is no crosstalk of signals between the micro-nano optical fibers sensing proximity and the micro-nano optical fibers sensing touch.
In specific implementation, a 200 μm interval is arranged between the micro-nano optical fiber for sensing proximity sense and the micro-nano optical fiber for sensing contact sense, namely, the thickness of the isolation layer 5 is 200 μm, so as to isolate proximity sense and contact sense sensing signals.
The flexible substrate 1, the isolation layer 5 and the flexible film 7 are made of the same material, and the light guide characteristic of the micro-nano optical fiber can be realized by adopting the material with the refractive index larger than that of air but smaller than that of the micro-nano optical fiber.
The refractive index of the humidity sensitive layer material is larger than that of air but smaller than that of the micro-nano optical fiber, so that the light guide characteristic of the micro-nano optical fiber is ensured
In order to ensure that the designed sensor can sense the proximity, the humidity sensitive layer selected for sensing the humidity change needs to be ensured. In the specific implementation, the material can be perfluorosulfonic acid-crystal violet mixed solution
The micro-nano optical fiber waist region for sensing contact sense and the tapering transition regions 3 at the two ends of the waist region are wrapped on the flexible substrate 1 by the isolating layer 5 for isolating proximity-contact sense signals, and the diameter of the waist region 4 is about 1.9-2.1 mu m.
The waist region of the micro-nano optical fiber part for sensing proximity is covered by a thin film 7 of the micro-nano optical fiber for sensing proximity and a separation layer 5 for separating proximity-contact sensing signals, the waist region of the micro-nano optical fiber part is covered by a sensitive material 8 for sensing proximity, and the diameter of the waist region of the micro-nano optical fiber is about 1.1-1.3 mu m.
Specific implementation to increase the response range of the proximity-contact sense sensor, the waist length of the micro-nano optical fiber is increased to around 1.5 cm.
The micro-nano optical fiber is obtained by the following steps: single mode fiber (kangning, 9/125 μm) was fixed on a self-made fiber tapering platform, utilizing electrolyzed water generated H 2 The single mode fiber was heated to a molten state and then the fiber tapering stage was moved toward each other at a speed of 0.1 mm/s.
In order to increase the waist length of the micro-nano optical fiber, after the fiber tapering platform moves towards each other for 5s at the speed of 0.1mm/s, the tapering platform simultaneously moves in the same direction at the speed of 2mm/s, so that the fiber waist gradually tapers and becomes long until the waist diameter is 1.9-2.1 mu m and the waist length is about 1.3-1.7 cm, and then the fiber is formed by stopping stretching and elongation and cooling.
The prepared micro-nano optical fiber for sensing the touch sense is placed on a flexible substrate 1 in a linear mode and then is wrapped by an isolating layer 5. According to the same preparation method, a micro-nano optical fiber with the diameter of 1.1-1.3 mu m and the waist region length of 1.4-1.8 mu m for sensing proximity sense is placed on an isolating layer 5 in a linear mode, and then covered by a flexible film 7, and part of the waist region is covered by a sensitive material 8 for sensing proximity sense.
Therefore, the micro-nano optical fibers are embedded in the flexible material, and the proximity sense-contact sense sensor embedded by the flexible material has good stability and robustness.
The proximity sense and the contact sense of the invention are respectively realized by sensing humidity and pressure.
The sensing proximity sense is realized by sensing humidity, and the sensitive material of the humidity sensitive layer 8 is a humidity sensitive material, so that the designed sensor is ensured to be sensitive to the proximity sense.
The humidity is conducted to the humidity sensitive material of the humidity sensitive layer 8, when the humidity is increased, the absorption characteristic of the humidity sensitive material is changed under the characteristic absorption wavelength, and different humidity is obtained by monitoring the signal change of the white light source 10 conducted to the spectrometer 11 through the proximity micro-nano optical fiber, so that the monitoring of proximity is realized.
The pressure is firstly applied to the humidity and pressure working window 9, and is applied to the waist region 4 of the micro-nano optical fiber for sensing the touch sense after passing through the humidity sensitive layer 8, the micro-nano optical fiber for sensing the touch sense above and the isolation layer 5, so that the waist region 4 deforms, the light signal transmitted by the waist region 4 generates bending loss, and the pressure is obtained by monitoring the signal change of the light beam emitted by the white light source 12, which is transmitted to the spectrometer 13 after passing through the micro-nano optical fiber for sensing the touch sense, thereby realizing the monitoring of the touch sense.
In a specific implementation, a humidity testing device 14 for applying humidity to perform humidity detection test and a mechanical testing device 15 for applying pressure to perform pressure detection test are further arranged on the humidity and pressure working window 9 to perform test proximity sensing and contact sensing by simulating the application of humidity and pressure respectively.
Embodiments of the invention are as follows:
the preparation and technical effects of the proximity-contact sensor based on micro-nano optical fibers of the present invention are described below by taking Polydimethylsiloxane (PDMS), perfluorosulfonic acid/crystal violet (Nafion-CV), single mode fiber (Corning, 9/125 μm) as examples.
1. Preparation process
In the present embodiment, the flexible substrate 1, the isolation layers 5 and 7 are all made of PDMS with refractive index of 1.397, which is used for confining light well to SiO-based materials 2 Micro-nano optical fiber of material.
(1) Preparation of flexible substrate 1: mixing 0.9mL of PDMS and 0.09mL of curing agent, uniformly stirring, placing on a glass substrate, standing for 10 minutes, and placing on a heating table at 80 ℃ for heating for 15 minutes to form a PDMS flexible substrate 1 with the thickness of 500 mu m.
(2) Placement of micro-nano optical fibers to sense touch: the prepared micro-nano optical fiber with the diameter of 1.9-2.1 mu m and the waist length of 1.3-1.7 cm is placed on the PDMS flexible substrate 1 in a linear mode.
(3) Preparation of isolation layer 5 for isolating proximity-contact sense signals: mixing 0.35mL of PDMS and 0.035mL of curing agent, uniformly stirring, placing on the surface of the micro-nano optical fiber for sensing the touch, standing for 10 minutes, and placing on a heating table at 80 ℃ for heating for 15 minutes to form a PDMS film 5 with the thickness of 200 mu m.
(4) Placement of micro-nano optical fibers for perceived proximity: the prepared micro-nano optical fiber with the diameter of 1.1-1.3 mu m and the waist length of 1.4-1.8 cm is placed on the PDMS isolation layer 5 in a linear mode.
(5) Preparation of humidity and pressure working window 9: PDMS and curing agent were mixed at 5:1, a PDMS film with high hardness and 500 μm thickness was prepared by a hole puncher with a diameter of 5mm to form a 5mm through hole in the middle of the PDMS film, and a PDMS hard film with a through hole with a size of 1cm×1cm was placed on the perceived micro-nano optical fiber.
(6) Preparation of a film 7 covering a perceived proximity micro-nano optical fiber: mixing 0.35mL of PDMS and 0.035mL of curing agent, uniformly stirring, placing on a micro-nano optical fiber with a sense of proximity except a sense temperature and pressure working window 9, standing for 10 minutes, placing on a heating table at 80 ℃ for heating for 15 minutes, and forming a PDMS film 7 with a thickness of 200 mu m.
(7) Preparation of humidity sensitive layer 8: 40mg of Crystal Violet (CV) was dissolved in 10mL of methanol, and after uniform mixing, 0.15mL of CV solution was extracted and added to 1mL of Nafion solution. After mixing well, 4. Mu.L of Nafion-CV solution was extracted and dropped into the humidity and pressure working window 9. After heating on a 60℃heating table for 5 minutes, a Nafion-CV film 8 of 1 μm thickness was formed.
2. Humidity test
In this embodiment, the prepared sensor is placed in a self-made humidity chamber with variable humidity, and only by changing the humidity in the humidity chamber, two ends of the micro-nano optical fiber sensor are respectively connected with a white light source 10 and a spectrometer 11, and the change of the spectrum with humidity is shown in fig. 2.
The test finds that: at 620nm wavelength, the transmittance decreases with increasing humidity. The transmittance change corresponding to 620nm wavelength was extracted, as shown in fig. 3, indicating that: the humidity was in the range of 40% RH to 80% RH, and the transmittance decreased linearly with increasing humidity, with a change rate of 1.88%/% RH. Meanwhile, a response time chart of the sensor is shown in fig. 4. If T90 time is to be: i.e. the time to reach the final stable value of 90% is set as the response time, which is only 120ms when the relative humidity changes from 50% to 100%, indicating that the response time of the sensor is very fast.
3. Pressure testing
In this embodiment, the prepared sensor is placed in a room temperature environment, the mechanical testing device is started to apply pressure to the waist region, only the pressure applied to the sensor is changed, and meanwhile, two sides of the sensor are respectively connected with the white light source 12 and the spectrometer 13, and a spectrum diagram of the transmittance changing with the pressure is shown in fig. 5.
Tests show that under the same pressure condition, the longer the wavelength is, the larger the transmittance change is, and the higher the response sensitivity is; the shorter the wavelength, the smaller the change in transmittance, and the lower the response sensitivity.
The transmittance versus pressure curve for different wavelengths is shown in FIG. 6.
The test shows that the absolute value of the pressure sensitivity response is 6.2%/kPa at 900nm wavelength -1 The method comprises the steps of carrying out a first treatment on the surface of the At a wavelength of 500nm, the absolute value of the pressure sensitivity response is 0.8%/kPa -1 。
4. Proximity-contact sense cooperative sensing
In this embodiment, the sensor can record, distinguish and display the whole finger approaching-contacting-pressing-leaving process in real time. The process involves four events, respectively: bare finger proximity (Event 1), fingered finger proximity (Event 2), fingered finger contact (Event 3) and three consecutive bare finger contact procedures (Event 4).
The two ends of the micro-nano optical fiber for sensing the proximity sense and the sensing the contact sense are respectively connected with the white light source and the spectrometer, and the transmittance diagram of the micro-nano optical fiber proximity sense-contact sense sensor in different events is shown in fig. 7. The top graph of fig. 7 is the output signal curve of the micro-nano fiber for perceived proximity and the bottom graph of fig. 7 is the output signal curve of the micro-nano fiber for perceived tactile.
The test finds that: when the bare finger approaches the sensor and the distance between the bare finger and the sensor is kept at about 0.5cm, the relative humidity of the bare finger is as high as 95%, the transmittance of the humidity sensor is obviously reduced, and the transmittance of the pressure sensor is not changed in the approaching process (Event 1); in contrast, when the fingered digit is in proximity to but not in contact with the sensor, the transmittance of the sensor monitoring humidity and pressure is unchanged (Event 2) as the fingered moist air is isolated by the glove. When the finger with the finger stall contacts the sensor, the humidity and pressure sensor responds quickly to the applied humidity and pressure (Event 3) due to the deformation of the micro-nano optical fiber after physical contact.
When a bare finger contacts the sensor and applies pressure, the transmittance of the humidity sensor and the transmittance of the pressure sensor are obviously reduced, and the transmittance of the pressure sensor is obviously increased along with the release of the applied pressure, and meanwhile, the transmittance of the humidity sensor is maintained at a lower level. Finally, when the finger is away, both humidity and pressure sensors show good reversibility in terms of transmittance (Event 4). It is shown that the sensor can not only recognize the proximity and contact process, but also distinguish between bare finger proximity and fingerstall finger proximity.
Claims (7)
1. A proximity sense-contact sense sensor based on micro-nano optical fiber is characterized in that: the flexible substrate (1), two stretched micro-nano optical fibers, an isolating layer (5) and a flexible film (7), wherein the flexible substrate (1), the isolating layer (5) and the flexible film (7) are sequentially arranged in a laminated mode, a first micro-nano optical fiber is arranged between the flexible substrate (1) and the isolating layer (5), a second micro-nano optical fiber is arranged between the isolating layer (5) and the flexible film (7), the two micro-nano optical fibers are all arranged in parallel along a straight line, and the second micro-nano optical fiber is positioned right above the first micro-nano optical fiber;
the two micro-nano optical fibers are respectively a micro-nano optical fiber for sensing proximity sense and a micro-nano optical fiber for sensing contact sense, the micro-nano optical fiber for sensing contact sense is positioned between the flexible substrate (1) and the isolation layer (5), and the micro-nano optical fiber for sensing proximity sense is positioned between the isolation layer (5) and the flexible film (7);
a humidity sensitive layer (8) is arranged on the micro-nano optical fiber for sensing proximity between the isolation layer (5) and the flexible film (7), and a humidity and pressure working window (9) is arranged at the flexible film (7) above the humidity sensitive layer (8);
the humidity sensitive layer (8) is made of humidity sensitive material.
2. The micro-nano fiber based proximity-contact sensor according to claim 1, wherein: both micro-nano optical fibers comprise an unstretched part (2) at two ends, a middle waist region and a tapering transition region (3) connected between the unstretched part (2) at two ends and the middle waist region.
3. The micro-nano fiber based proximity-contact sensor according to claim 1, wherein: the waist region of the micro-nano optical fiber for sensing proximity sense is positioned right above the waist region of the micro-nano optical fiber for sensing contact sense, and the humidity sensitive layer (8) is arranged above the waist region of the micro-nano optical fiber for sensing proximity sense.
4. The micro-nano fiber based proximity-contact sensor according to claim 1, wherein: the diameters of the waist regions of the two micro-nano optical fibers are different, and the diameter of the waist region (6) of the micro-nano optical fiber for sensing proximity sense is smaller than the diameter of the waist region (4) of the micro-nano optical fiber for sensing contact sense.
5. The micro-nano fiber based proximity-contact sensor according to claim 1, wherein: and two ends of the two micro-nano optical fibers are respectively connected with a white light source and a spectrometer.
6. The micro-nano fiber based proximity-contact sensor according to claim 1, wherein: the flexible substrate (1), the isolation layer (5) and the flexible film (7) are made of the same material, and the refractive index of the flexible substrate is larger than that of air, but smaller than that of the micro-nano optical fiber.
7. The micro-nano fiber based proximity-contact sensor according to claim 6, wherein: besides being sensitive to humidity, the refractive index of the humidity sensitive layer material needs to be larger than that of air and smaller than that of the micro-nano optical fiber.
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