Background technology
In the thermal imprint process process of nano impression, need to implement monitoring to force of impression.When imprint head during near substrate, can judge whether imprint head aims at, and carry out corresponding calibration operation that force of impression at this moment only has several newton by the monitoring of power sensor; When beginning to impress, imprint head is pushed down substrate fully, and the force of impression of this moment can reach hundreds of even thousands of newton.If adopt traditional single shaft power sensor, in above-mentioned two processes, just need to change different sensors, will bring like this problems such as again demarcation, this will greatly affect the precision of nano impression.
And for example in the pulling strengrth test process of metal wire rod, great changes have taken place along with the difference of material and diameter is understood for intensity wiry, from a few milli oxen to tens Ns.This just need to have a kind ofly can realize the different measuring scope, and the power sensor of different resolution satisfies the demand of above-mentioned situation.
Existing power sensor is based on the metering system of foil gauge mostly, foil gauge is attached to the surface of testee, when foil gauge produces microdeformation, by resistance bridge deformation signal is converted to voltage signal, analog voltage signal is converted to the digital signal of being convenient to Computer Processing by AD converter again.
Some other power sensor is such as piezoelectric force transducer, piezoresistive force sensor, capacitance-type force sensor and optical force sensor.
Piezoelectric force transducer is by piezoelectric under external force, and the principle that can produce a voltage signal is come power is measured, but the shortcoming of this power sensor is the increase along with external force, and the electric signal of piezoelectric unit output will be decayed fast; Piezoresistive force sensor is by pressure drag material under external force, and its resistance the significant principle that changes can occur measures external force, and this power sensor is subjected to neighbourhood noise, such as temperature etc., impact very large; The capacitance-type force sensor utilization under external force, electric capacity up and down between two sheet metals displacement change, thereby the principle that causes the change of capacitance size is measured external force, the power sensor of this form has been widely used in micro electronmechanical (MEMS) field at present, for the manufacture of high-precision Micro-force sensor; The optical force sensor detects semi-girder distortion under external force by optical device, and the principle that optical signalling is converted to voltage signal is measured external force, and for example atomic force microscope (AFM) is exactly to utilize such principle to come work.
Take a broad view of existing power sensor, the power sensor of every kind of form has its relative merits, needs to adopt the sensor of particular form under the specific occasion.But still there is following some deficiency in existing power sensor:
(1) existing power sensor can't be realized two-stage even multistage power resolution, and its measurement range is subject to the restriction of resolution.In the situation that multistage power resolution requirement is arranged, can't satisfy the measurement requirement;
(2) output signal of existing power sensor all is a faint simulating signal, is subjected to the impact of neighbourhood noise very large;
(3) precision and the resolution of existing power sensor are subject to the force measurement scope.That is to say that when the precision of sensor and resolution improved, the measurement range of sensor will reduce, vice versa.
Summary of the invention
The power sensor that the purpose of this invention is to provide a kind of two-stage power resolution based on flexible parallel-crank mechanism, this sensor adopts two groups of flexible parallelogram straight-line motion mechanisms to overlap on the one hand, utilizes on the substrate deformation mechanism of self leaf spring to realize force measurement; On the other hand, adopt grating scale (Fiber Bragg Grating-FBG) displacement transducer to measure by the size of dynamometry by the detection of reflected light wavelength.The output signal of this metering system is digital signal, does not need the sampling through A/D, thereby has greatly reduced the interference of outside noise signal, and its resolution only depends on the resolution of grating scale grid.
The present invention is a kind of power sensor of the two-stage power resolution based on flexible parallel-crank mechanism, and this power sensor includes substrate (1), upper cover plate (2), grating scale displacement transducer (3), probe (4) and grating scale installing plate
(5);
The center of the upper face (1F) of substrate (1) is provided with groove (1G), and this groove (1G) is used for placing grating scale installing plate (5);
Be provided with threaded hole (1E) around the upper face (1F) of substrate (1), this threaded hole (1E) is used for realizing the installation of upper cover plate (2) and substrate (1);
The front face (1C) of substrate (1) is provided with A through hole (1D), and the end that this A through hole (1D) is used for probe (4) passes;
The upper line cutting technology that adopts of the upper face (1F) of substrate (1) is cut with the first joint-cutting (11), the second joint-cutting (12), the 3rd joint-cutting (13), the 4th joint-cutting (14), the 5th joint-cutting (15) and the 6th joint-cutting (16);
The lower side cut (11C) of the first joint-cutting (11) is provided with the first spacing preiection (11A), and the upper side cut (11D) of the first joint-cutting (11) is provided with the second spacing preiection (11B);
The lower side cut (14C) of the 4th joint-cutting (14) is provided with the 3rd spacing preiection (14A), and the upper side cut (14D) of the 4th joint-cutting (14) is provided with the 4th spacing preiection (14B);
It is the first flexible leaf spring (15A) between the upper side cut of one end of the 5th joint-cutting (15) and the second joint-cutting (12); It is the second flexible leaf spring (15B) between the upper side cut 11D of one end of the 5th joint-cutting (15) and the first joint-cutting (11); It is the 3rd flexible leaf spring (15C) between the upper side cut of the other end of the 5th joint-cutting (15) and the 3rd joint-cutting (13); It is the 4th flexible leaf spring (15D) between the upper side cut (14D) of the other end of the 5th joint-cutting (15) and the 4th joint-cutting (14); It is the 5th flexible leaf spring (16A) between the lower side cut of one end of the 6th joint-cutting (16) and the second joint-cutting (12); It is the 6th flexible leaf spring (16B) between the lower side cut (11C) of one end of the 6th joint-cutting (16) and the first joint-cutting (11); It is the 7th flexible leaf spring (16C) between the lower side cut of the other end of the 6th joint-cutting (16) and the 3rd joint-cutting (13); It is the 8th flexible leaf spring (16D) between the lower side cut (14C) of the other end of the 6th joint-cutting (16) and the 4th joint-cutting (14); The first joint-cutting (11), the 4th joint-cutting (14), the 5th joint-cutting 15 and the 6th joint-cutting 16 are divided into belly board (17) with substrate (1); The second joint-cutting (12), the 3rd joint-cutting (13), the 5th joint-cutting (15) and the 6th joint-cutting (16) are divided into terminal platform (18) with substrate (1);
The upper face of upper cover plate (2) is provided with long recess (21), is provided with B through hole (22), B threaded hole (26) in this long recess (21); Described long recess (21) is used for grating scale displacement transducer (3) is installed, and the sensitivity end (3B) of grating scale displacement transducer (3) passes B through hole (22); Described B threaded hole (26) is used for screw and passes, and this screw passes B threaded hole (26) and is used for realizing grating scale displacement transducer (3) is installed in the long recess (21) of upper cover plate (2);
The lower face of upper cover plate (2) is provided with lordosis stage body (24) and rear boss body (25), is respectively equipped with C through hole (23) on lordosis stage body (24) and the rear boss body (25), and this C through hole (23) is used for screw and passes; Described screw passes in the threaded hole (1E) that C through hole (23) rear thread is connected to substrate (1), thereby realizes the installation of upper cover plate (2) with substrate (1);
The grating scale (3A) of grating scale displacement transducer (3) is installed on the grating scale installing plate (5), the sensitivity end (3B) of sensor (3) is used for reading the displacement on the grating scale (3A) after passing B through hole (22) on the long recess (21) of upper cover plate (2); The thread end (4A) of probe (4) is threaded in the threaded hole (18A) of an end of platform (18) endways.
The advantage of two-stage power resolution sensor of the present invention is:
1. adopt the mode of Wire EDM to process at sensitive components (substrate).Utilize two groups of flexible parallelogram straight-line motion mechanism overlap joints, it is in order to guarantee the high precision rectilinear motion of belly board, the i.e. parasitic error of reducing mechanism that two groups of compliant mechanisms are arranged symmetrically with.
2. this sensitive components (substrate) is a part, does not need to assemble, thereby has effectively avoided the problems such as friction that conventional force sensors brought by assembling, gap.
3. form one group of flexible parallelogram straight-line motion mechanism at four inboard leaf springs of sensitive components (substrate), and four leaf springs in the outside form another and organize flexible parallelogram straight-line motion mechanism.Two groups of flexible parallelogram straight-line motion mechanisms are arranged symmetrically with, when external force F effect by popping one's head in 4 when acting on the terminal platform 18, the soft segment generation elastic deformation of two groups of compliant mechanisms has guaranteed the high precision rectilinear motion of terminal platform 18.
4. adopt the grating scale displacement transducer as tested force measurement equipment, measure by the size of dynamometry by the detection of reflected light wavelength.The output signal of this metering system is digital signal, does not need the sampling through A/D, thereby has greatly reduced the interference of outside noise signal, and its resolution only depends on the resolution of grating scale grid.
5. the device of the two-stage power resolution sensor of the present invention's design is few, simple in structure, and measuring accuracy is high.
Description of drawings
Fig. 1 is the external structure of two-stage power resolution sensor of the present invention.
Figure 1A is the face of the facing structural drawing of two-stage power resolution sensor of the present invention.
Figure 1B is the right flank structural drawing of two-stage power resolution sensor of the present invention.
Fig. 1 C is the face of the looking up structural drawing of two-stage power resolution sensor of the present invention.
Fig. 1 D is the exploded view of two-stage power resolution sensor of the present invention.
Fig. 1 E is the structural drawing at another visual angle of displacement transducer in the two-stage power resolution sensor of the present invention.
Fig. 2 is the structural drawing of substrate of the present invention.
Fig. 2 A is the vertical view of substrate of the present invention.
Fig. 3 is the structural drawing of upper cover plate of the present invention.
Fig. 4 is the two-stage power exploded view of two-stage power resolution sensor of the present invention.
Among the figure: 1. the left gap of substrate 1A. right end clearance 1B. 1C. front face
1D.A through hole 1E.A threaded hole 1F. upper face 1G. groove 11. first joint-cuttings
11A. the first spacing preiection 11B. the second spacing preiection 12. second joint-cuttings
13. the 3rd joint-cutting 14. the 4th joint-cutting 14A. the 3rd spacing preiection 14B. the 4th spacing preiection
15. the 5th joint-cutting 15A. first flexible leaf spring 15B. the second flexible leaf spring
15C. the 3rd flexible leaf spring 15D. the 4th flexible leaf spring 16. the 6th joint-cutting
16A. the 5th flexible leaf spring 16B. the 6th flexible leaf spring 16C. the 7th flexible leaf spring
16D. the 8th flexible leaf spring 17. belly boards 18. terminal platform 18A.C threaded holes
2. upper cover plate 21. long recess 22.B through hole 23.C through holes 24. lordosis stage bodies
25. rear boss body 26.B threaded hole 3. grating scale displacement transducer 3A. grating scales
3B. responsive end 4. probes 5. grating scale installing plates
Embodiment
The present invention is described in further detail below in conjunction with accompanying drawing.
Substrate 1 material of the power sensor of the present invention's design is aluminium alloy 7075, adopts the mode of Wire EDM to process.It is mainly formed by two groups of flexible parallelogram straight-line motion mechanism overlap joints.In addition, it is the high precision rectilinear motion that has guaranteed belly board that two groups of compliant mechanisms are arranged symmetrically with, and has namely reduced the parasitic error of mechanism.Simultaneously, this sensor construction main body is a part, does not need to assemble, thereby has effectively avoided the problems such as friction that conventional force sensors brought by assembling, gap.The characteristics of this sensor maximum are that it can realize two-stage power resolution effectively, and this is that conventional force sensors can't realize.Because this sensor utilization is the deformation mechanism of self leaf spring, so its resolution can reach very high.
Shown in Fig. 1, Figure 1A, Figure 1B, Fig. 1 C, Fig. 1 D, the present invention is a kind of power sensor of the two-stage power resolution based on flexible parallel-crank mechanism, and this power sensor includes substrate 1, upper cover plate 2, grating scale displacement transducer 3, probe 4 and grating scale installing plate 5.
Sensor 3 is installed in the long recess 21 of upper cover plate 2, and the sensitivity end 3B of grating scale displacement transducer 3 passes the B through hole 22 on the long recess 21;
Upper cover plate 2 is fixed on the substrate 1 by screw all around, and has right end clearance 1A and left gap 1B between upper cover plate about 2 and the substrate about 1; Reserve the gap in the left and right sides between upper cover plate 2 and the substrate 1, guaranteed that two-stage power resolution sensor of the present invention does the time spent being subject to external force F, the motion of two groups of design flexible parallelogram straight-line motion mechanisms no longer is subjected to the impact of other resistances on the substrate 1.
Probe 4 thread end is installed in the C threaded hole 18A of terminal platform 18 after passing the through hole of front face 1C of substrate 1.
(1) substrate 1
Shown in Fig. 2, Fig. 2 A, the center of the upper face 1F of substrate 1 is provided with groove 1G, and this groove 1G is used for placing grating scale installing plate 5;
Be provided with threaded hole 1E around the upper face 1F of substrate 1, this threaded hole 1E is used for realizing the installation of upper cover plate 2 and substrate 1;
The front face 1C of substrate 1 is provided with A through hole 1D, and the end that this A through hole 1D is used for probe 4 passes;
The upper line cutting technology that adopts of the upper face 1F of substrate 1 is cut with the first joint-cutting 11, the second joint-cutting 12, the 3rd joint-cutting 13, the 4th joint-cutting 14, the 5th joint-cutting 15 and the 6th joint-cutting 16;
The lower side cut 11C of the first joint-cutting 11 is provided with the first spacing preiection 11A, and the upper side cut 11D of the first joint-cutting 11 is provided with the second spacing preiection 11B;
The lower side cut 14C of the 4th joint-cutting 14 is provided with the 3rd spacing preiection 14A, and the upper side cut 14D of the 4th joint-cutting 14 is provided with the 4th spacing preiection 14B;
Be the first flexible leaf spring 15A between the upper side cut of one end of the 5th joint-cutting 15 and the second joint-cutting 12;
Be the second flexible leaf spring 15B between the upper side cut 11D of one end of the 5th joint-cutting 15 and the first joint-cutting 11;
Be the 3rd flexible leaf spring 15C between the upper side cut of the other end of the 5th joint-cutting 15 and the 3rd joint-cutting 13;
Be the 4th flexible leaf spring 15D between the upper side cut 14D of the other end of the 5th joint-cutting 15 and the 4th joint-cutting 14;
Be the 5th flexible leaf spring 16A between the lower side cut of one end of the 6th joint-cutting 16 and the second joint-cutting 12;
Be the 6th flexible leaf spring 16B between the lower side cut 11C of one end of the 6th joint-cutting 16 and the first joint-cutting 11;
Be the 7th flexible leaf spring 16C between the lower side cut of the other end of the 6th joint-cutting 16 and the 3rd joint-cutting 13;
Be the 8th flexible leaf spring 16D between the lower side cut 14C of the other end of the 6th joint-cutting 16 and the 4th joint-cutting 14.
In the present invention, the first joint-cutting 11, the 4th joint-cutting 14, the 5th joint-cutting 15 and the 6th joint-cutting 16 are divided into belly board 17 with substrate 1.
In the present invention, the second joint-cutting 12, the 3rd joint-cutting 13, the 5th joint-cutting 15 and the 6th joint-cutting 16 are divided into terminal platform 18 with substrate 1.
In the present invention, four leaf springs of substrate 1 inboard (the first flexible leaf spring 15A, the 3rd flexible leaf spring 15C, the 5th flexible leaf spring 16A, the 7th flexible leaf spring 16C) form one group of flexible parallelogram straight-line motion mechanism, and four leaf springs in substrate 1 outside (the second flexible leaf spring 15B, the 4th flexible leaf spring 15D, the 6th flexible leaf spring 16B, the 8th flexible leaf spring 16D) form another and organize flexible parallelogram straight-line motion mechanism.Two groups of flexible parallelogram straight-line motion mechanisms are arranged symmetrically with, when external force F effect by popping one's head in 4 when acting on the terminal platform 18, the leaf spring place generation elastic deformation of two groups of compliant mechanisms has guaranteed the high precision rectilinear motion of terminal platform 18.
In the present invention, substrate 1 aluminium alloy 7075 materials.
(2) upper cover plate 2
Referring to Fig. 1, Figure 1A, Figure 1B, shown in Figure 3, the upper face of upper cover plate 2 is provided with long recess 21, is provided with B through hole 22, B threaded hole 26 in this long recess 21; Described long recess 21 is used for grating scale displacement transducer 3 is installed, and the sensitivity end 3B of grating scale displacement transducer 3 passes B through hole 22.Described B threaded hole 26 is used for screw and passes, and this screw passes B threaded hole 26 and is used for realizing grating scale displacement transducer 3 is installed in the long recess 21 of upper cover plate 2.
The lower face of upper cover plate 2 is provided with lordosis stage body 24 and rear boss body 25, is respectively equipped with C through hole 23 on lordosis stage body 24 and the rear boss body 25, and this C through hole 23 is used for screw and passes; Described screw passes among the threaded hole 1E that C through hole 23 rear threads are connected to substrate 1, thereby realizes the installation of upper cover plate 2 with substrate 1.
In the present invention, come grating scale displacement transducer 3 is carried out the restriction of installation site by the upper face design long recess 21 at upper cover plate 2, guaranteed that probe 4 does the time spent being subject to external force F, the grating scale 3A that is installed on the grating scale installing plate 5 can be read by the sensitivity end 3B of grating scale displacement transducer 3; Simultaneously guaranteed that also two-stage power resolution sensor of the present invention utilizes the installation direction of grating scale displacement transducer 3.
In the present invention, upper cover plate 2 aluminium alloys 5052 materials processings.
(3) the grating scale displacement transducer 3
Shown in Fig. 1, Figure 1A, Figure 1B, Fig. 1 D, Fig. 1 E, in the present invention, the grating scale 3A of grating scale displacement transducer 3 is installed on the grating scale installing plate 5, after the sensitivity end 3B of sensor 3 passes B through hole 22 on the long recess 21 of upper cover plate 2, be used for reading the displacement on the grating scale 3A, thereby realize the metering of displacement.
In the present invention, the Mercury 3500 serial displacement transducers that grating scale displacement transducer 3 selects U.S. MicroE systems company to produce, its linear resolution can be regulated between 5 nanometers at 5 microns.
In the present invention, the responsive precision of grating scale displacement transducer 3 is chosen raster resolution on the grating scale 3A by the demand of using.
(4) probe 4
Shown in Fig. 1, Figure 1A, Figure 1B, Fig. 1 C, Fig. 1 D, probe 4 thread end 4A is threaded in the threaded hole 18A of an end of platform 18 endways.
In the present invention, 4 aluminium alloys, 5052 materials processings of popping one's head in.
Referring to shown in Figure 4, the two-stage power resolution sensor based on flexible parallel-crank mechanism of the present invention's design realizes that the principle of work of two-stage power resolution is:
The second flexible leaf spring 15B on the substrate 1, the 4th flexible leaf spring 15D, the 6th flexible leaf spring 16B and the 8th flexible leaf spring 16D form the similar rigidity value k that has
aThe first spring.Described the first spring drives belly board 17 motions under stress condition.
The first flexible leaf spring 15A on the substrate 1, the 3rd flexible leaf spring 15C, the 5th flexible leaf spring 16A and the 7th flexible leaf spring 16C form the similar rigidity value k that has
bThe second spring.Described the second spring owing to be connected with belly board 17, drives terminal platform 18 motions under stress condition.
When by dynamometry hour, the first spring and the second spring are series relationship, and rigidity value at this moment is k
1=k
ak
b/ (k
a+ k
b); When tested external force was larger, the motion of belly board 17 was limited by the first spacing preiection 11A and the 3rd spacing preiection 14A, and this moment, the first spring failure only had the second spring to work, and rigidity is k
2=k
bOwing to realized the variation of two stage stiffness at a substrate 1, therefore when carrying out same displacement detecting, sensor of the present invention can realize having the measurement requirement of power resolution and the two-stage power measurement range of two-stage.
The present invention is a kind of power sensor of the two-stage power resolution based on flexible parallel-crank mechanism, and the principle of work of this power sensor is:
(A) 4 be subject in the situation of external pressure when probe, belly board and terminal platform be backward motion (referring to shown in Figure 1) simultaneously;
(B) grating scale 3A is with terminal platform 18 motion same displacement;
(C) the sensitivity end of grating scale displacement transducer detects the amount of exercise of terminal platform 18;
(D) when middle platform 17 and the first spacing preiection 11A with after the 3rd spacing preiection 14A contacts, the belly board stop motion, terminal platform continues motion;
(E) moving terminal platform 18 continues the backward directions motion with grating scale 3A;
(F) the sensitivity end of grating scale displacement transducer detects the amount of exercise of terminal platform 18 again.
The power sensor based on the two-stage power resolution of flexible parallel-crank mechanism of the present invention design, be based on the power sensor of grating scale (Fiber Bragg Grating-FBG), when external force by popping one's head in 4 when acting on the terminal platform 18, terminal platform 18 moves with the grating scale 3A section that moves, at this moment, the length of the grid part on the grating scale 3A and the reflectivity of nucleus can along with changing, be measured by the size of dynamometry by the detection of reflected light wavelength.The output signal of this metering system is digital signal, does not need the sampling through A/D, thereby has greatly reduced the interference of outside noise signal, and its resolution only depends on the resolution of the upper grid of grating scale 3A.