CN207215314U - For structural mechanics fiber-optic grating sensor encapsulating structure - Google Patents
For structural mechanics fiber-optic grating sensor encapsulating structure Download PDFInfo
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- CN207215314U CN207215314U CN201721019338.7U CN201721019338U CN207215314U CN 207215314 U CN207215314 U CN 207215314U CN 201721019338 U CN201721019338 U CN 201721019338U CN 207215314 U CN207215314 U CN 207215314U
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Abstract
The utility model discloses one kind to be used for structural mechanics fiber-optic grating sensor encapsulating structure, including：Protection pipe, its interior encapsulation are fixed with pedestal, metallic elastic body and optical fiber；The metallic elastic body is fixedly installed on the pedestal, it is welded and fixed on the metallic elastic body through low-melting glass and the optical fiber is set, the optical fiber surface is provided with polyimide coating layer, the optical fiber is provided with the optical fiber grating structure inscribed by femto-second laser pulse, and the optical fiber grating structure is between two low-melting glass pads of the optical fiber on the metallic elastic body.The optical fiber of resistant to elevated temperatures polyimide coating layer is set by using surface, and the optical grating construction formed using quarter grid are carried out to the optical fiber by femto-second laser, it ensure that optical fiber coating will not be burned under 270 DEG C to 380 DEG C welding temperatures of low-melting glass, the encapsulation of low smelting point glass solder is realized, can solve the problems, such as that existing fiber optical grating construction mechanics sensor tensile strength is low and creep simultaneously.
Description
Technical field
Fiber-optic grating sensor encapsulation field is the utility model is related to, more particularly to one kind is used for structural mechanics fiber grating
Sensor-packaging structure.
Background technology
Fiber-optic grating sensor has two biggest advantages：First, information is to wavelength absolute encoding；Second, belong to Intrinsical
Sensor.Therefore, the outstanding advantage of fiber-optic grating sensor is：Passive intrinsic safety, small and light, be not afraid of thunderbolt, anti-electromagnetism is done
Disturb, many reference amounts at the same measure, overlength distance transmission, precision is high, property is stable, environmental suitability is strong.In recent years, fiber grating passes
Sensor is widely used in industries such as petrochemical industry, electric power, traffic, highway bridges.
The core sensing element of optical fiber Bragg raster structural mechanics sensor is optical fiber Bragg raster, existing frequently-used quarter
Grid method is to peel off to write grating by phase mask after optical fiber coating, but will certainly be in light during coat is peeled off
Fine surface leaves permanent mechanical crackle and causes mechanical damage, can substantially reduce the tensile strength of optical fiber.
Due to the sensitive fragile characteristic of fiber grating element, its encapsulation technology, which turns into, makes optical fiber grating structure mechanics biography
Key technology in sensor engineer applied.Existing frequently-used packaged type includes：1) with special epoxide-resin glue by optical fiber light
Grid are encapsulated in metal tube or on sheet metal.But following defect be present：First, epoxide-resin glue belongs to organic matter, easy to aging point
Solution, is unfavorable for the long-term use of adverse circumstances；2) encapsulated with glue, but because the creep of glue causes long-term use of transducer calibration
The phenomenon of " zero point " drift, limits its use in engineering project；3) it is using low-melting glass+common to also have a kind of encapsulation
The form of grating, tensile strength are only 0.4kg, i.e., can be broken, and seriously limit the application of FBG sensor.
At present optical fiber grating structure mechanics sensor encapsulate make during in order to ensure that finished product sensor possesses one
Fixed tensile strength, the mode of epoxy resin embedding adhesive is largely employed, i.e., by the optical fiber light of common acrylate coat
Grid are directly bonded in surface of elastomer with epoxide-resin glue, and test purpose is realized by its cooperative transformation with elastomer.Should
(wherein, 1 is elastic matrix to the structure of epoxide-resin glue embedding as shown in Figure 1；2 be grating；3 be casting glue), but this use
Following defect be present in the optical fiber grating structure mechanics sensor of epoxide-resin glue embedding：Because the creep of epoxide-resin glue in itself is special
Property, can be with epoxide-resin glue using the optical fiber grating structure mechanics sensor of the packaging technology during long-term use
Creep drives the fiber grating for being encapsulated in inside that the drift that creep causes sensor wavelength zero point occurs together, ultimately results in sensing
Device failure can not use.The creep test result of this optical fiber grating structure mechanics sensor using epoxide-resin glue embedding is such as
Shown in Fig. 2, two fiber gratings are put together side by side in experiment, a pre-stretching 1.5nm, encapsulated using epoxide-resin glue,
Other one static to be placed on side, experiences identical temperature, does temperature-compensating.In the experiment that the cycle is half a year, remember daily
One group of data is recorded, data processing uses below equation：
In above formula, λ0：The initial wavelength of test gratings, unit：nm；
λ：The centre wavelength of test gratings, unit：nm；
λT：The actual measurement wavelength of temperature compensation sensor, unit：nm；
The initial wavelength of temperature compensation sensor, unit：nm；
BT：The temperature coefficient of temperature compensation sensor, unit：℃/pm；
Bε：The temperature coefficient of test gratings, unit：℃/pm；
Obtained data are to remove the wavelength after temperature influences, in the test that the cycle is half a year, daily one group of record
Data, drawn after arrangement：Using epoxide-resin glue test gratings under static state, removing temperature influences, and wavelength persistently drops
It is low.For the sensor of this encapsulating structure due to epoxide-resin glue creep, the wavelength persistently reduced will be used as measurement error to continue shadow
Ring the performance of sensor.
There is another to use the packaged type of low-melting glass welding at present, naked grating both ends are welded on elastomer
It is upper that (coat of ordinary optic fibre is acrylate, and general 120 DEG C of heatproof, the melt temperature of low melting point glass for bonding is 270 DEG C.
Have a problem that：During welding, low-melting glass not yet melts, but acrylate-coated layer has been burned out.
So low-melting glass must be welded on bare fibre by common technique, cause optical fiber more crisp.) low-melting glass is higher with it
Chemical stability and the performance such as bond strength, solve creep problem caused by epoxide-resin glue characteristic.But such encapsulation
Structure draws another question again, i.e., the tensile strength of packaged optical fiber grating structure mechanics sensor is relatively low, normal light
Grid are needed first to peel off coat when scribing, and mechanical crackle will certainly be produced in stripping process, and intensity is difficult to be guaranteed.
For the low-melting glass packaged type of ordinary optic fibre grating, inventor has carried out substantial amounts of strength test, and experimental data proves
Its tensile strength is 0.4kg or so, i.e., is about 4.5nm with the wavelength movement of the fiber-optic grating sensor of its encapsulation, limits very much
The engineer applied of fiber-optic grating sensor, What is more can all damage in transportation.Ordinary optic fibre grating tensile strength is real
Result is tested as shown in figure 3, commonly (wherein, 41 be Bragg gratings to the structure of grating as shown in Figure 4；42 be fiber core；43 are
Covering；44 be mechanical crackle；45 be acrylate-coated layer；A is incident light；B penetrates light to return).
Utility model content
Based on the problems of prior art, the purpose of this utility model is to provide one kind and is used for structural mechanics optical fiber light
Gate sensor encapsulating structure, can solve the problems, such as that existing fiber optical grating construction mechanics sensor tensile strength is low and creep simultaneously.
The purpose of this utility model is achieved through the following technical solutions：
The utility model embodiment provides one kind and is used for structural mechanics fiber-optic grating sensor encapsulating structure, including：
Protection pipe, its interior encapsulation are fixed with pedestal, metallic elastic body and optical fiber；
The metallic elastic body is fixedly installed on the pedestal, is welded and fixed on the metallic elastic body through low-melting glass
The optical fiber is set, and the optical fiber surface is provided with polyimide coating layer, and the optical fiber is provided with and inscribed by femto-second laser pulse
Optical fiber grating structure, the optical fiber grating structure be in the optical fiber on the metallic elastic body two low-melting glasses weldering
Between contact.
What the utility model embodiment provided it can be seen from above-mentioned technical scheme provided by the utility model is used for structure
The method for packing and encapsulating structure of mechanics fiber-optic grating sensor, its advantage are：
The optical fiber of resistant to elevated temperatures polyimide coating layer is set by using surface, and used by femto-second laser to the light
Fibre carries out carving the optical grating construction that grid are formed, and ensure that optical fiber coating is not under 270 DEG C to 380 DEG C welding temperatures of low-melting glass
It can be burned, realize the encapsulation of low smelting point glass solder, can solve existing fiber optical grating construction mechanics sensor simultaneously and resist
Tensile strength is low and the problem of creep.The packaged type retains the more preferable mechanical strength of optical fiber and has more preferable creep resistance
Energy.
Brief description of the drawings
It is required in being described below to embodiment in order to illustrate more clearly of the technical scheme of the utility model embodiment
The accompanying drawing used is briefly described, it should be apparent that, drawings in the following description are only some implementations of the present utility model
Example, on the premise of not paying creative work, can also be according to these accompanying drawings for one of ordinary skill in the art
Obtain other accompanying drawings.
Fig. 1 is the fiber grating schematic diagram for the epoxide-resin glue embedding that prior art provides；
Fig. 2 is the creep test result schematic diagram of Fig. 1 optical fiber grating structure mechanics sensor；
Fig. 3 is the ordinary optic fibre grating tensile strength experimental result schematic diagram that prior art provides；
Fig. 4 is the structural representation for the common grating that prior art provides；
Fig. 5 is the encapsulating structure schematic diagram for the fiber-optic grating sensor that the utility model embodiment provides；
Fig. 6 is the creep pair of fiber-optic grating sensor and existing fiber grating sensor that the utility model embodiment provides
Than testing result schematic diagram；
Fig. 7 is the fiber-optic grating sensor of the utility model embodiment offer and resisting for existing acrylate-coated layer grating
Tensile strength contrast experiment's schematic diagram；
In Fig. 1：1- elastic matrixes；2- gratings；3- casting glues；
In Fig. 4：41-Bragg gratings；42- fiber cores；43- coverings；44- mechanical crackles；45- acrylate-coated layers；
A- incident lights；B-, which is returned, penetrates light；
In Fig. 5：51- matrixes；The polyimides grating that 52- femtosecond lasers are inscribed；53- low-melting glass solder joints；54- elasticity
Metallic object；55- protection pipes.
Embodiment
With reference to particular content of the present utility model, the technical scheme in the embodiment of the utility model is carried out it is clear,
It is fully described by, it is clear that described embodiment is only the utility model part of the embodiment, rather than whole implementation
Example.Based on embodiment of the present utility model, those of ordinary skill in the art are obtained under the premise of creative work is not made
Every other embodiment, belong to the scope of protection of the utility model.
The utility model embodiment provides a kind of encapsulating structure for structural mechanics fiber-optic grating sensor, such as Fig. 5 institutes
Show that (wherein, 51 be matrix, and 52 be the polyimides grating that femtosecond laser is inscribed, and 53 be low-melting glass solder joint, and 54 be elasticity gold
Belong to body, 55 be protection pipe), the encapsulating structure includes：
Protection pipe, its interior encapsulation are fixed with pedestal, metallic elastic body and optical fiber；
Metallic elastic body is fixedly installed on pedestal, is welded and fixed setting optical fiber, light through low-melting glass on metallic elastic body
Fine surface is provided with polyimide coating layer, and optical fiber is provided with the optical fiber grating structure inscribed by femto-second laser pulse, fiber grating
Structure is between two low-melting glass pads of the optical fiber on metallic elastic body.
In above-mentioned encapsulating structure, optical fiber is provided with the optical fiber grating structure inscribed by femto-second laser pulse and is：
Exposed point by point along optical fiber using the femtosecond laser beam of focusing, form the refractive index of fiber grating fibre core and periodically divide
Cloth carries out inscribing manufactured optical grating construction the point-by-point inscription method of grating is made；
Or
Optical fiber surface is carried out to inscribe manufactured optical fiber as the phase-mask method of exposure light source using femtosecond pulse
Optical grating construction.
Being welded and fixed in above-mentioned encapsulating structure, on metallic elastic body through low-melting glass sets the low-melting glass of optical fiber to weld
Jointing temp is：270 DEG C~380 DEG C.
In above-mentioned encapsulating structure, the thickness that optical fiber surface is provided with polyimide coating layer is：1~3mm.
The utility model carries polyimide coating layer fiber grating low smelting point glass using femto-second laser quarter grid
Glass welding encapsulation technology solves the problems, such as creep；It is low to solve existing fiber optical grating construction mechanics sensor tensile strength simultaneously
Problem.
Referring to Fig. 5, the method for packing of the above-mentioned encapsulating structure for structural mechanics fiber-optic grating sensor is as follows：
Polyimide coating layer is set in optical fiber surface to be packaged, using femto-second laser pulse to being applied provided with polyimides
The optical fiber surface of coating carries out inscription and optical grating construction is made；
Welded with low-melting glass and the optical fiber at optical grating construction both ends is directly welded on metallic elastic body respectively, by metal
Elastomer is arranged on pedestal, by the fixed envelope of metallic elastic body, the optical grating construction being welded on the metallic elastic body and pedestal
In protection pipe, that is, complete the encapsulation of fiber-optic grating sensor.
In above-mentioned method for packing, the optical fiber surface provided with polyimide coating layer is inscribed using femto-second laser pulse
Optical grating construction, which is made, is：
Variations in refractive index is produced using femto-second laser pulse induction optical fiber fibre core polyimide coating layer is provided with to surface
Optical fiber surface carries out inscription and optical grating construction is made.
In above-mentioned method for packing, the optical fiber surface provided with polyimide coating layer is inscribed using femto-second laser pulse
Optical grating construction, which is made, is：
Exposed point by point along optical fiber using the femtosecond laser beam of focusing, the refractive index of fiber core is formed periodic distribution and come
The point-by-point inscription method that grating is made carries out inscription optical grating construction is made；
Or
Inscription is carried out to optical fiber surface as the phase-mask method of exposure light source using femtosecond pulse grating knot is made
Structure.
In above-mentioned method for packing, welded with low-melting glass and the optical fiber at optical grating construction both ends is directly welded at metal respectively
Low-melting glass welding temperature in elastomer is：270 DEG C~380 DEG C.
The utility model embodiment is specifically described in further detail below.
Method for packing provided by the utility model for structural mechanics fiber-optic grating sensor is：It is provided with using surface poly-
Grating both ends are directly welded at metallic elastic body by the fiber grating of imide coat layer, low smelting point glass solder technology
On, then elastomer is positioned on pedestal and is protected by with protection pipe, the encapsulating structure of formation is referring to Fig. 5.
In above-mentioned method for packing, produce variations in refractive index using femto-second laser pulse induction optical fiber fibre core and inscribe fiber grating
Mainly have two kinds：First, point-by-point inscription method, is exposed, makes the refractive index of fibre core point by point using the femtosecond laser beam of focusing along optical fiber
Form periodic distribution and fiber grating is made；Second, phase-mask method, its principle is similar with traditional phase-mask method, simply
Exposure light source improves femtosecond pulse.The new point-by-point direct writing technology high efficient and flexible of femtosecond laser manufactures high-end FBG ---
fsFBG.It is advantageous that：The direct write FBG on the optical fiber that user specifies or provides；The nonlinear optical effect production of femtosecond laser
Raw extremely stable non-erasable grating is as senser element；To 1000 degrees Celsius of extreme stability；It is straight through coat
Write, retain the more preferable mechanical strength of optical fiber, retain the excellent properties of special coat, far above conventional stripping --- re-coating method
The mechanical strength of fiber grating；Radioresistance, moisture resistant, resistant to hydrogen darken, electromagnetism interference.
In above-mentioned method for packing, the polyimides used in optical fiber surface coat is a kind of exotic material, is had high
The performance such as heat resistance, excellent chemical stability, good electrical insulating property and high mechanical properties.In order to ensure in low melting point glass
Coat will not be burned under 270 DEG C of welding temperatures of glass, and the utility model is used in optical fiber coating polyimide coating layer.
Low-melting glass welding low-melting glass used is a kind of low temperature sealing glass solder, can be directly by gold in encapsulation
Belong to pipe sleeve and optical fiber seal, without optical fiber surface is metallized, wellability is good, can reach level Hermetic Package；Chemically stable compared with
It is good, do not produce gas during sealing, noresidue after sealing；For hermetic seal temperature than relatively low, sealing temperature scope is 270 DEG C
It is~380 DEG C, easily operated；Strong applicability, relatively conventional encapsulation, the component life after being encapsulated using the product are grown.More conventional ring
The packaging technology of oxygen resin glue, fiber grating weld by low-melting glass, and contact point stability is good, caused by eliminating creep
The drift of wavelength zero point.
The encapsulating structure that the utility model method for packing is formed is long-term compacted with conventional epoxy glue packaged fiber grating
Become experimental data contrast as shown in fig. 6, there it can be seen that wavelength zero point caused by the creep of the utility model encapsulating structure is floated
Shifting is less than conventional epoxy glue packaged fiber grating.
The encapsulating structure that the utility model method for packing is formed and common acrylate coat fiber-optic grating sensor
Tensile strength is contrasted as shown in fig. 7, it can be seen that the tensile strength of the utility model encapsulating structure is better than conventional acrylic
Ester coat fiber-optic grating sensor.
It is described above, the only preferable embodiment of the utility model, but the scope of protection of the utility model is not
This is confined to, any one skilled in the art can readily occur in the technical scope that the utility model discloses
Change or replacement, should all cover within the scope of protection of the utility model.Therefore, the scope of protection of the utility model should
It is defined by the protection domain of claims.
Claims (4)
1. one kind is used for structural mechanics fiber-optic grating sensor encapsulating structure, it is characterised in that including：
Protection pipe, its interior encapsulation are fixed with pedestal, metallic elastic body and optical fiber；
It is fixedly installed the metallic elastic body on the pedestal, setting is welded and fixed through low-melting glass on the metallic elastic body
The optical fiber, the optical fiber surface are provided with polyimide coating layer, and the optical fiber is provided with the light inscribed by femto-second laser pulse
Fine optical grating construction, the optical fiber grating structure are in two low-melting glass pads of the optical fiber on the metallic elastic body
Between.
2. according to claim 1 be used for structural mechanics fiber-optic grating sensor encapsulating structure, it is characterised in that the light
Fibre is provided with the optical fiber grating structure inscribed by femto-second laser pulse：
Exposed point by point along optical fiber using the femtosecond laser beam of focusing, the refractive index of fiber grating fibre core is formed periodic distribution and come
The point-by-point inscription method that grating is made carries out inscribing manufactured optical grating construction；
Or
Optical fiber surface is carried out to inscribe manufactured fiber grating as the phase-mask method of exposure light source using femtosecond pulse
Structure.
3. according to claim 1 be used for structural mechanics fiber-optic grating sensor encapsulating structure, it is characterised in that the gold
It is welded and fixed on category elastomer through low-melting glass and sets the low-melting glass welding temperature of the optical fiber to be：270 DEG C~380
℃。
4. according to claim 1 be used for structural mechanics fiber-optic grating sensor encapsulating structure, it is characterised in that the light
Fine surface be provided with polyimide coating layer thickness be：1~3mm.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201721019338.7U CN207215314U (en) | 2017-08-15 | 2017-08-15 | For structural mechanics fiber-optic grating sensor encapsulating structure |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201721019338.7U CN207215314U (en) | 2017-08-15 | 2017-08-15 | For structural mechanics fiber-optic grating sensor encapsulating structure |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110160668A (en) * | 2019-05-20 | 2019-08-23 | 深圳供电局有限公司 | Optical fiber optical grating array sensor and its encapsulating structure |
| CN114623918A (en) * | 2022-02-28 | 2022-06-14 | 浙江大学 | Low-pass filtering fiber grating hydrophone adopting tensile coating for sensitization |
-
2017
- 2017-08-15 CN CN201721019338.7U patent/CN207215314U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110160668A (en) * | 2019-05-20 | 2019-08-23 | 深圳供电局有限公司 | Optical fiber optical grating array sensor and its encapsulating structure |
| CN110160668B (en) * | 2019-05-20 | 2021-12-14 | 深圳供电局有限公司 | Fiber grating array sensor and packaging structure thereof |
| CN114623918A (en) * | 2022-02-28 | 2022-06-14 | 浙江大学 | Low-pass filtering fiber grating hydrophone adopting tensile coating for sensitization |
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Effective date of registration: 20190509 Address after: Room 609, Block B, 320 Pubin Road, Jiangpu Street, Nanjing City, Jiangsu Province, 210000 Patentee after: Nanjing Pinao Photoelectric Technology Co., Ltd. Address before: 314512 Second Floor of Building No. 26 Zikai East Road, Shimen Town, Tongxiang City, Jiaxing City, Zhejiang Province Patentee before: Zhejiang Zhiyuan Photoelectric Technology Co., Ltd. |