CN103123251A - Optical axis and thickness measurement method and device of differential confocal internal-focusing lens - Google Patents

Optical axis and thickness measurement method and device of differential confocal internal-focusing lens Download PDF

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CN103123251A
CN103123251A CN2010101218481A CN201010121848A CN103123251A CN 103123251 A CN103123251 A CN 103123251A CN 2010101218481 A CN2010101218481 A CN 2010101218481A CN 201010121848 A CN201010121848 A CN 201010121848A CN 103123251 A CN103123251 A CN 103123251A
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lens
differential confocal
light
intensity sensor
light intensity
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CN103123251B (en
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赵维谦
邱丽荣
杨佳苗
潘莹莹
孙若端
沙定国
苏大图
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Beijing Institute of Technology BIT
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Abstract

The invention belongs to the technical field of optical precision measurement and relates to an optical axis and thickness measurement method and a device of a differential confocal internal-focusing lens. By means of an internal-focusing objective lens, the method utilizes an auto-collimation method to adjust the optical axis of the lens precisely; utilizes the characteristic that when a differential confocal response curve passes the absolute zero point, the vertex of a differential confocal light cone and the surface vertex of the lens to be measured can coincide to achieve the precise positioning of the surface vertex of the lens and to obtain a numerical aperture angle of emergent lights in two-time positioning of the vertex of the differential confocal light cone; and utilizes a ray tracing formula to calculate the central thickness of the lens. Meanwhile, an annular pupil is introduced during the light path measurement, the influence of aberration on a measurement result is reduced. By combining differential confocalization with internal focusing for the first time, and providing optical axis and thickness measurement principle of the differential confocal internal-focusing lens, the lens optical axis and thickness measurement method and device of the differential confocal internal-focusing lens has the advantages of being high in measurement speed, high in precision, high in sensitivity, simple in structure and long in working distance, and is applicable to non-contact high-precision measurement of the light axis and the central thickness of lens.

Description

Differential confocal internal focusing method lens axis and method for measuring thickness and device
Technical field
The invention belongs to technical field of optical precision measurement, relate to a kind of differential confocal internal focusing method lens axis and method for measuring thickness and device, the contactless high-precision that can be used for lens axis and thickness is measured.
Technical background
In optical field, the measurement of lens axis and thickness is significant.Lens axis and thickness are two important parameters in optical system, and the quality of its crudy can be to imaging of optical systems mass formation considerable influence.Particularly for the lens in photo-etching machine objective lens, the contour performance optical system of camera space, need to carry out accurate adjustment to the gap of lens, radial deflection and optical axis drift angle according to optical axis, radius-of-curvature, refractive index and the thickness of lens in camera lens.Take photo-etching machine objective lens as example, the deviation of each simple lens optical axis and thickness can cause the aberration of photo-etching machine objective lens, affects the image quality of object lens.Widely used " digital camera lens " and " CCD scanning lens " at present, the precision of its lens axis and thickness is generally tens of microns, need to have high-precision instrument measure and check, so lens axis and thickness are that optical element must be examined and one of strict project of controlling.
At present, the lens thickness measuring technique can be divided into two kinds of contact type measurement and non-contact measurements.
Contact type measurement generally uses hand-held clock gauge or miking.During measurement, the accuracy of lens center point position will directly affect measuring accuracy, therefore checker's measured lens that will move around when measuring, seek peak (convex lens) or minimum point (concave mirror), thereby measuring speed is slow, error is large, and the high transmission optical material that uses at present, material is softer, and during measurement, gauge head moves at lens surface, easily scratches lens surface.
For the problem that contact type measurement exists, domestic scholars has also been carried out correlative study.In " the explicit lens thickness measuring instrument of raster count " literary composition of delivering in " practical measuring technology " in 1999, author designed a kind of lens thickness measuring instrument that consists of as the precision measurement of length device with grating sensor, according to dissimilar optical lens and measuring accuracy requirement, can adopt the combination of multi-form gauge head and measuring seat to measure, measuring accuracy is brought up to 1 μ m.(the patent No.: 200620125116.9) that Chinese patent " is measured the device of optical lens center thickness ", adopted in the method for measuring column top placement measured lens smelting tool, the damage that when having avoided seeking the lens surface summit, gauge head moves around lens are caused at lens surface.
Non-contact measurement often has image measurement method, coplanar capacitance method, the confocal method of white light and interferometric method.
In " based on the fit-up gap Research on on-line-measuring of image measurement technology " literary composition of delivering in " sensor technology " in 2005, introduced a kind of on-line measurement scheme based on image measurement technology, the picture that the gap is become in ccd video camera by optical system is delivered image measurement software after via the image pick-up card collection and is processed and analyze, and provides result by Survey Software.This method also can be applied to the measurement of lens thickness, but due to the impact that is subjected to camera imaging system, CCD resolving power, clear picture degree and calibration coefficient degree of accuracy etc., measuring error is in 15 μ m.
In " optical lens center thickness automatic tester " literary composition of delivering in " Chinese journal of scientific instrument " in 1994, utilize coplanar capacitance measurement lens thickness.At first as requested electric capacity gauge head and reference field are adjusted to a fixed position; Then measured lens is placed on reference field, the electric capacity of gauge head will change along with the gap between lens and gauge head; Go out by circuit measuring the voltage signal that changes corresponding to electric capacity at last, just can find out the relative variation of measured lens thickness, the sharpness of separation of the method is less than 5 μ m.But this method needs the signal voltage of known measured lens material and the relation curve of clearance before measuring, and in engineering reality, must accurately test coplanar electric capacity gauge head, to obtain authentic data as detecting foundation.
In " Noncontact measurement of central lens thickness " literary composition of delivering in " GLASS SCIENCE AND TECHNOLOGY " in 2005, adopt the confocal method of white light to measure lens thickness.At first this method utilizes after the white light scioptics probe that axial aberration forms that the measured lens surface vertices is positioned, and then calculates the thickness of lens by the spectral information of measured lens upper and lower surface summit reflection.The characteristics of the method are to realize real-time measurement, but white light is incoherent light, focus sensitivity and resolution is lower, operating distance limited (30 μ m-25mm).Particularly be difficult to accurate known measured lens in the refractive index at different wave length place, general is all by measuring the refractive index interpolation gained of certain wave strong point, this parameter is larger on the impact of measurement result, so this method is difficult to realize high-acruracy survey in actual applications.
Chinese patent " optical gauge of optical element the thickness " (patent No.: 87200715), utilize two interference systems to carry out non-cpntact measurement to lens thickness.This instrument is comprised of two Michelson interference systems, position according to two surfaces of white-light fringe to measured lens, and with measured lens and calibrated bolck relatively in the hope of the thickness of measured lens, to current still unsolved balsaming lens.The opaque optical element of visible light, the optical element of unknown material etc. is realized non-cpntact measurement.
Chinese patent " a kind of measurement mechanism of the micro-optical space " (patent No.: 93238743.8), adopt the polarized light interference method to measure thickness of sample.The incident white light forms interference fringe in two wave fronts that the sample upper and lower surface reflects to form on photodetector array after polarizer, birefringent prism, analyzer, get final product to get thickness of sample by the interference fringe spacing.Simultaneously add post lens that interference pattern is amplified along the fringe spacing direction between analyzer and photodetector array, reduced the requirement to photodetector array, measuring accuracy is 1-5%, but this method can only be used for measuring the thickness of glass plate.
Realizing that the key that lens thickness is measured has 3 points, is at first the optical axis of determining measured lens, is then to realize a kind of high precision, non-contacting optical alignment technology, the computational algorithm of final thickness can offset lens on the impact of optical path.
At present, the lens axis measuring technique mainly adopts the interior focusing object lens to eliminate the technology of optical axis deviation in conjunction with autocollimation method, this technology is by regulating the axial location of the focusing group in the interior focusing object lens, and then the numerical aperture angle of adjusting emergent light, in conjunction with autocollimation method, can eliminate well the lens axis deviation.In " the auto testing instrument Control System Design of infrared objective center deviation and realization " literary composition of for example delivering in " Hunan Industrial Professional Technology Academe journal " in 2007, it adopts reflective autocollimation principle, receive signal with CCD, and with the interior focusing objective lens design control system of full-automatic, the measured lens automatic rotation of focusing, thereby realize measurement to lens axis.
In recent years, the differential confocal technology in micro-imaging field is fast-developing both at home and abroad, this technology with axial Intensity response curve as opinion scale, has good optical chromatography ability, and owing to adopting light intensity as data message, compare image processing method and have higher anti-environmental interference ability.Chinese patent " the differential confocal scanning detection method with high spatial resolution " (patent No.: 200410006359.6) for example, it has proposed the ultra-discrimination differential confocal detection method, make the system axial resolving power reach nanoscale, and significantly improved the environment Ability of Resisting Disturbance, but differential confocal technology mainly is applicable to microcosmic micrometering field, and this technology and interior focusing object lens autocollimation method are merged mutually, realize that the measured lens optical axis detects and the lens surface location, then realize the report of lens axis and thickness high-acruracy survey, not yet see up to now.
Summary of the invention
The objective of the invention is to measure problem for the contactless high-precision that solves lens axis and thickness, proposed a kind of differential confocal internal focusing method lens axis and method for measuring thickness and device.The present invention makes differential confocal light cone summit scan along optical axis direction in conjunction with the interior focusing method, realizes the high precision adjustment of lens axis; Differential confocal light cone summit and the characteristic that the measured lens surface vertices overlaps when utilizing the differential confocal response curve to cross actual zero point, measured lens thickness high-acruracy survey is realized by the ray tracing algorithm then in the accurate location of realizing the measured lens surface vertices.
The objective of the invention is to be achieved through the following technical solutions.
As shown in Figure 1 differential confocal internal focusing method lens axis and method for measuring thickness is characterized in that:
(a) adjust the optical axis of measured lens, make itself and interior focusing object lens common optical axis;
(b) regulate the interior focusing object lens, make by the differential confocal light cone summit of interior focusing object lens outgoing and scan along optical axis direction, determine that by the actual zero point of surveying the differential confocal response curve differential confocal light cone summit and measured lens front surface coincide, the numerical aperture angle of the object lens of interior focusing at this moment emergent light is α 1
(c) continue to regulate the interior focusing object lens, make differential confocal light cone summit continue scanning along optical axis direction, again determine that by the absolute zero point value of surveying the differential confocal response curve differential confocal light cone summit and measured lens rear surface coincide, the numerical aperture angle of the object lens of interior focusing at this moment emergent light is α 2
(d) according to known parameters: interior focusing object lens emergent light cone height h 0, measured lens front surface radius-of-curvature r 1, air refraction n 0With the measured lens refractive index n, can calculate lens thickness by ray tracing formulas.
Ray tracing formulas in the described step of method (d) satisfies
d = r 1 + n 0 sin α 2 n · ( h 0 tan α 2 - h 0 tan α 1 - r 1 ) sin { α 2 + arcsin [ sin α 2 r 1 ( h 0 tan α 2 - h 0 tan α 1 - r 1 ) ] - arcsin [ n 0 sin α 2 n r 1 ( h 0 tan α 2 - h 0 tan α 1 - r 1 ) ] }
Calculate the measured lens thickness d by this formula.
The method of the optical axis of the adjustment measured lens in the described step of method (a) has following two kinds:
(1) use autocollimation method to adjust the optical axis of measured lens, at first differential confocal light cone summit is transferred near the centre of sphere of measured lens rear surface, surveyed by light intensity sensor and converge to its surperficial picture point A, adjust measured lens to rotating measured lens picture point not when in rotary moving till; Then differential confocal light cone summit is transferred near the measured lens front surface centre of sphere, is surveyed by light intensity sensor and converge to its surperficial picture point B, adjust measured lens to rotating measured lens picture point not when in rotary moving till; This moment measured lens and the same optical axis of interior focusing object lens.
(2) use autocollimation method to adjust the optical axis of measured lens, at first differential confocal light cone summit is transferred near the centre of sphere of measured lens rear surface, surveyed by light intensity sensor and converge to its surperficial picture point A; Then differential confocal light cone summit is transferred near the measured lens front surface centre of sphere, surveyed by light intensity sensor and converge to its surperficial picture point B; Adjusting measured lens overlaps with picture point B to picture point A; This moment measured lens and the same optical axis of interior focusing object lens.
Use annular pupil to block paraxial rays, form hollow measurement light cone, cut down aberration to the impact of measurement result.
As shown in Figure 3 differential confocal internal focusing method lens axis and measurer for thickness comprise pointolite, the first spectroscope, interior focusing object lens and differential confocal system; The first spectroscope, interior focusing object lens and measured lens are placed on the exit direction of light, the differential confocal system is placed on first spectroscopical reflection direction, measured lens surface with the first spectroscope with beam reflection to the differential confocal system, and coordinate differential confocal system to realize the accurate location on measured lens front surface summit and summit, measured lens rear surface.
The system of differential confocal described in device comprises the second spectroscope, the first light intensity sensor and the second light intensity sensor; The light that is reflected by the first spectroscope enters the differential confocal system, by the second spectroscope, light is divided into two-way, and one the tunnel is radiated at and is positioned on the first defocused light intensity sensor, and another road is radiated on the second light intensity sensor that is positioned at before burnt.
The system of differential confocal described in device can also comprise the second spectroscope, burnt front pin hole, defocused pin hole, the first light intensity sensor and the second light intensity sensor; The light that is reflected by the first spectroscope enters the differential confocal system, by the second spectroscope, light is divided into two-way, leads up to after defocused pin hole, be radiated on the first light intensity sensor, another road by pin hole before burnt after, be radiated on the second light intensity sensor.
The system of differential confocal described in device can also comprise the second spectroscope, burnt front microcobjective, defocused microcobjective, the first light intensity sensor and the second light intensity sensor; Wherein the object plane of defocused microcobjective is positioned at defocusedly, places the first light intensity sensor at it as the plane, before the object plane of microcobjective is positioned at Jiao before burnt, places the second light intensity sensor at it as the plane; The light that is reflected by the first spectroscope enters the differential confocal system, by the second spectroscope, light is divided into two-way, and the defocused microcobjective of leading up to is imaged on the first light intensity sensor, and another road is imaged on the second light intensity sensor by microcobjective before burnt.
Comprise main control computer, electromechanical controlling device and AD acquisition module; Main control computer obtains the differential confocal signal that is gathered by light intensity sensor by the AD acquisition module; Main control computer is regulated the numerical aperture angle of interior focusing object lens emergent light by the controller controller for electric consumption, realize that differential confocal light cone summit moves along the scanning of optical axis direction.
Beneficial effect:
The present invention contrasts prior art and has following innovative point:
1. this lens axis and method for measuring thickness utilize differential confocal to focus method the contactless high-precision location are realized on the measured lens surface, and to measured lens surface nondestructive wound, measuring speed is fast.
2. use the interior focusing object lens in light path, adopt the method scanning measured lens surface vertices position that changes emergent light numerical aperture angle, not only dwindle the range ability of mechanism, and strengthened the operating distance of device, increased the degree of depth that light cone enters into lens inside.
3. the present invention is merged differential confocal technology and interior focusing object lens autocollimation method mutually, can realize the accurate adjustment of measured lens optical axis, has reduced the measuring error of thickness.
4. introduce annular pupil in light path, block paraxial rays, form hollow measurement light cone, cut down the impact of aberration on measurement result.
The present invention contrasts prior art and has following remarkable advantage:
1. the accurate location that utilizes the good chromatography ability of differential confocal system to realize lens surface.
2. utilize the high axial resolution of differential confocal system to significantly improve measuring accuracy.
3. utilize the interior focusing object lens can realize fast accurate adjustment and location to the measured lens optical axis in conjunction with the autocollimation method.
4. differential working method can be cut down the environmental interference such as air turbulence to the impact of measuring accuracy.
Description of drawings
Fig. 1 is the schematic diagram of differential confocal internal focusing method lens axis of the present invention and method for measuring thickness;
Fig. 2 is the schematic diagram of the measured lens front and rear surfaces centre of sphere of the present invention;
Fig. 3 is the schematic diagram of differential confocal internal focusing method lens axis of the present invention and measurer for thickness;
Fig. 4 is the schematic diagram of the differential confocal device directly surveyed of the present invention;
Fig. 5 is the schematic diagram that the present invention uses the differential confocal device of pin hole detection;
Fig. 6 is the schematic diagram that the present invention uses the differential confocal device of microcobjective detection;
Fig. 7 is the schematic diagram of differential confocal internal focusing method lens axis of the present invention and thickness measure embodiment;
wherein: the 1-pointolite, 2-the first spectroscope, 3-interior focusing object lens, the 4-annular pupil, 5-measured lens front surface, 6-measured lens rear surface, the 7-adjustment rack, 8-differential confocal light cone summit, the 9-measured lens, 10-the first light intensity sensor, the defocused pin hole of 11-, 12-the second light intensity sensor, pin hole before Jiao 13-, 14-the second spectroscope, 15-differential confocal system, the 16-measured lens rear surface centre of sphere, the 17-measured lens front surface centre of sphere, 18-pointolite generating means, the 19-electromechanical controlling device, the 20-main control computer, the 21-AD acquisition module, the 22-AD acquisition module, the defocused microcobjective of 23-, microcobjective before Jiao 24-, 25-optical fiber, the 26-laser instrument, the fixing group of 27-interior focusing object lens, 28-interior focusing object lens focusing group, the fixing group of 29-interior focusing object lens, the 30-CCD detector, the 31-CCD detector, the 32-image pick-up card, the 33-image pick-up card, the three-dimensional platform of adjusting of 34-, the 35-panoramic table.
Embodiment
The invention will be further described below in conjunction with drawings and Examples.
The method of differential confocal and interior focusing has been merged in the present invention, its basic thought is to use autocollimation method by the interior focusing object lens, lens axis is carried out the high precision adjustment, use differential confocal technology that lens surface is accurately located, realize that the contactless high-precision of lens axis and thickness is measured.Simultaneously can introduce annular pupil in optical path, block paraxial rays, form hollow measurement light cone, cut down the impact of aberration on measurement result.
Adopt biconvex lens as measured lens 9 in embodiment, known its parameter satisfies the correctness that is used for the described method of check this patent, and wherein the radius-of-curvature of lens as shown in Figure 2, is followed successively by r from left to right 1=195.426mm, r 2=-140.270mm; Refractive index is followed successively by from left to right: n 0=1, n=1.5143, the thickness of known lens and interval are d=12mm.
Embodiment 1
As shown in Figure 7, differential confocal internal focusing method lens axis and measurer for thickness, comprise pointolite generating means 18, be successively placed on the first spectroscope 2, interior focusing object lens 3 and the annular pupil 4 of pointolite 1 emergent light direction, also comprise the differential confocal system 15 that is placed on the first spectroscope 2 reflection directions, wherein measured lens 9 surfaces and the first spectroscope 2 with beam reflection the second spectroscope 14 to the differential confocal system 15; The second spectroscope 14 is divided into two-way with light, and reflected light is through defocused pin hole 11 back lighting ccd detectors 30, and transmitted light is pin hole 13 back lighting ccd detectors 31 before overfocus; Image pick-up card 32 gathers ccd detector 30 and surveys the simulating signal that obtains and convert digital signal to, and image pick-up card 33 gathers ccd detector 31 and surveys the simulating signal that obtains and convert digital signal to, and two paths of signals is transferred to main control computer 20 jointly.
Main control computer 20 obtains differential response signal; Main control computer 20 is connected with electromechanical controlling device 19, makes its movement that drives interior focusing object lens focusing group 28, thereby realizes that differential confocal light cone summit 8 moves in the scanning of optical axis direction.
When measured lens 9 is as shown in Figure 2 biconvex lens, as shown in Figure 7, differential confocal internal focusing method lens axis and method for measuring thickness, its measuring process is:
At first, start the Survey Software in main control computer 20, input correlation parameter, comprise the radius-of-curvature r of measured lens front surface 5 1, air refraction n 0Refractive index n with measured lens 9.
Then, open LASER Light Source 26, the laser that LASER Light Source 26 is sent forms pointolite 1 after optical fiber 25 transmission.The hollow cone that the light that pointolite 1 sends forms after the first spectroscope 2, interior focusing object lens 3 and annular pupil 4 is mapped on measured lens 9, is entered after the first spectroscope 2 reflections in differential confocal system 15 by the light of measured lens 9 reflection.As shown in Figure 5, the second spectroscope 14 is divided into two-way with light, and reflected light is through defocused pin hole 11 back lighting the first light intensity sensors 10, and transmitted light is pin hole 13 back lighting the second light intensity sensors 12 before overfocus.The first light intensity sensor 10 is that ccd detector 30, the second light intensity sensors 12 are ccd detector 31.
Measured lens 9 is arranged on three-dimensional the adjustment on platform 34, adjusts platform 34 along the rotating shaft rotation of panoramic table 35 with three-dimensional.By adjusting the three-dimensional platform 34 of adjusting, make measured lens 9 and the same optical axis of interior focusing object lens 3, avoid the measuring error that causes because of light shaft offset, set-up procedure comprises following three steps:
(1), main control computer 20 drives the movement of interior focusing object lens focusing groups 28 by controller controller for electric consumption 19, the differential confocal light cone summit 8 of its outgoing is scanned along optical axis direction;
(2), as shown in Figure 2, in the time of near differential confocal light cone summit 8 is scanned up to the measured lens rear surface centre of sphere 16, shining the corrugated of measured lens rear surface 6 and the sphere of measured lens rear surface 6 is close, the light that is reflected by measured lens rear surface 6 by interior focusing object lens 3 after, reflexed to differential confocal system 15 by the first spectroscope 2, form gradually picture point clearly on ccd detector 30, be designated as picture point A.When picture point is the most clear, stop the scanning to differential confocal light cone summit 8.Rotate back to turntable 35 and drive measured lens 9 rotations, whether the picture point A that observes on ccd detector 30 moves with the rotation of measured lens 9.Adjust three-dimensional adjustment platform 34 until picture point A does not move with the rotation of measured lens 9;
(3), continue controlling interior focusing object lens 3 makes differential confocal light cone summit 8 continue scanning along optical axis, in the time of near differential confocal light cone summit 8 is scanned up to the measured lens front surface centre of sphere 17, equally, shining the corrugated of measured lens rear surface 6 and the sphere of measured lens rear surface 6 is close, the light that is reflected by measured lens rear surface 6 by interior focusing object lens 3 after, reflexed to differential confocal system 15 by the first spectroscope 2, form gradually picture point clearly on ccd detector 30, be designated as picture point B.When picture point is the most clear, stop the scanning to differential confocal light cone summit 8.Rotate back to turntable 35 and drive measured lens 9 rotations, observe the picture point B that on ccd detector 30, detection obtains and whether move with the rotation of measured lens 9.Adjust three-dimensional adjustment platform 34 until picture point B does not move with the rotation of measured lens 9.
At this moment, the measured lens front surface centre of sphere 17 and the measured lens rear surface centre of sphere 16 all are positioned on the optical axis of interior focusing object lens 3, measured lens 9 and the same optical axis of interior focusing object lens 3.
Main control computer 20 is controlled interior focusing object lens 3 and is adjusted differential confocal light cone summit 8 along optical axis direction scanning, observes from main control computer 20 image of adopting back by image pick-up card 32 and image pick-up card 33.Main control software carries out Digital Image Processing to adopting back image, obtains differential response signal.Can obtain successively from front to back the position that four differential response signals are crossed actual zero point, main control software records differential response signal when crossing actual zero point for the second time, for the third time is respectively α from the numerical aperture angle of the light of interior focusing object lens 3 outgoing 1=16.699 °, α 2=12.094 °, can be calculated by following ray tracing formulas the thickness d of measured lens 9:
d = r 1 + n 0 sin α 2 n · ( h 0 tan α 2 - h 0 tan α 1 - r 1 ) sin { α 2 + arcsin [ sin α 2 r 1 ( h 0 tan α 2 - h 0 tan α 1 - r 1 ) ] - arcsin [ n 0 sin α 2 n r 1 ( h 0 tan α 2 - h 0 tan α 1 - r 1 ) ] }
In formula, known parameters comprises the height h of interior focusing object lens 3 outgoing light cones 0The radius-of-curvature r of=6mm, measured lens front surface 5 1=195.426mm, air refraction n 0=1 and measured lens 9 refractive index ns=1.5143.Be the thickness d=12.002mm of measured lens 9 by ray tracing result of calculation.
But be no more than 0.002mm by the result in the present embodiment confirmatory measurement gap and the deviation of known numeric value 12mm, the precision of the method is compared with the measuring error of classic method dozens of micron, has quite high precision.
In the measuring process of the present embodiment, because the interior focusing object lens are unique moving components, so measuring process is very rapid, can complete the scanning of whole optical axis direction within half a minute, the data in later stage are processed and are completed by the Survey Software in main control computer 20, and the time that software is processed is in 1 second.
Due in the present embodiment before measuring beginning, adopt autocollimation method to adjust optical axis, make measured lens 9 and interior focusing object lens common optical axis, avoid the measuring error that causes because of light shaft offset.Suppose optical axis deviation greater than 1 °, cause that the clearance measurement error of measured lens 9 is respectively 0.050mm, therefore, the present embodiment is improved the clearance measurement precision by optical axis correction.
Embodiment 2
As Fig. 4 and shown in Figure 7, the differential confocal system 15 with the differential confocal system 15 in embodiment 1 Fig. 7 replaces with Fig. 4 can consist of embodiment 2.That after light entered differential confocal system 15, the second spectroscope 14 was divided into two-way with light, indirect lighting the first light intensity sensor 10, transillumination the second light intensity sensor 12 with embodiment 1 difference.All the other measuring methods are identical with embodiment 1 with device.
Embodiment 3
As shown in Figure 6 and Figure 7, the differential confocal system 15 with the differential confocal system 15 in embodiment 1 Fig. 7 replaces with Fig. 6 can consist of embodiment 3.With embodiment 1 difference be, after light enters differential confocal system 15, the second spectroscope 14 is divided into two-way with light, reflected light through after defocused microcobjective 23 in the first surperficial imaging of light intensity sensor 10, transmitted light before overfocus after microcobjective 24 in the second surperficial imaging of light intensity sensor 12; Wherein the object plane of defocused microcobjective 23 is positioned at defocusedly, places the first light intensity sensor 10 at it as the plane, before the object plane of microcobjective 24 is positioned at Jiao before burnt, places the second light intensity sensor 12 at it as the plane.All the other measuring methods are identical with embodiment 1 with device.
This embodiment has realized the contactless high-precision measurement of lens axis and thickness by a series of measure, realized differential confocal internal focusing method lens axis and method for measuring thickness and device, had the measured lens not damaged, measuring accuracy is high, operating distance is long, the advantage such as easy to use.
Below by reference to the accompanying drawings the specific embodiment of the present invention is described; but these explanations can not be understood to limit scope of the present invention; protection scope of the present invention is limited by the claims of enclosing, and any change on claim of the present invention basis is all protection scope of the present invention.

Claims (9)

1. differential confocal internal focusing method lens axis and method for measuring thickness is characterized in that:
(a) adjust the optical axis of measured lens, make itself and interior focusing object lens common optical axis;
(b) regulate the interior focusing object lens, make by the differential confocal light cone summit of interior focusing object lens outgoing and scan along optical axis direction, determine that by the actual zero point of surveying the differential confocal response curve differential confocal light cone summit and measured lens front surface coincide, the numerical aperture angle of the object lens of interior focusing at this moment emergent light is α 1
(c) continue to regulate the interior focusing object lens, make differential confocal light cone summit continue scanning along optical axis direction, again determine that by the absolute zero point value of surveying the differential confocal response curve differential confocal light cone summit and measured lens rear surface coincide, the numerical aperture angle of the object lens of interior focusing at this moment emergent light is α 2
(d) according to known parameters: interior focusing object lens emergent light cone height h 0, measured lens front surface radius-of-curvature r 1, air refraction n 0With the measured lens refractive index n, can calculate lens thickness by ray tracing formulas.
2. differential confocal internal focusing method lens axis according to claim 1 and method for measuring thickness is characterized in that: the ray tracing formulas in described (d) satisfies
d = r 1 + n 0 sin α 2 n · ( h 0 tan α 2 - h 0 tan α 1 - r 1 ) sin { α 2 + arcsin [ sin α 2 r 1 ( h 0 tan α 2 - h 0 tan α 1 - r 1 ) ] - arcsin [ n 0 sin α 2 nr 1 ( h 0 tan α 2 - h 0 tan α 1 - r 1 ) ] }
Calculate the measured lens thickness d by this formula.
3. differential confocal internal focusing method lens axis according to claim 1 and method for measuring thickness, it is characterized in that: the method for the optical axis of the adjustment measured lens in described (a) has following two kinds:
(1) use autocollimation method to adjust the optical axis of measured lens, at first differential confocal light cone summit is transferred near the centre of sphere of measured lens rear surface, surveyed by light intensity sensor and converge to its surperficial picture point A, adjust measured lens to rotating measured lens picture point not when in rotary moving till; Then differential confocal light cone summit is transferred near the measured lens front surface centre of sphere, is surveyed by light intensity sensor and converge to its surperficial picture point B, adjust measured lens to rotating measured lens picture point not when in rotary moving till; This moment measured lens and the same optical axis of interior focusing object lens.
(2) use autocollimation method to adjust the optical axis of measured lens, at first differential confocal light cone summit is transferred near the centre of sphere of measured lens rear surface, surveyed by light intensity sensor and converge to its surperficial picture point A; Then differential confocal light cone summit is transferred near the measured lens front surface centre of sphere, surveyed by light intensity sensor and converge to its surperficial picture point B; Adjusting measured lens overlaps with picture point B to picture point A; This moment measured lens and the same optical axis of interior focusing object lens.
4. according to claim 1 and 2 or 3 described differential confocal internal focusing method lens axis and method for measuring thickness, is characterized in that: use annular pupil to block paraxial rays, form hollow measurement light cone, cut down aberration to the impact of measurement result.
5. differential confocal internal focusing method lens axis and measurer for thickness, comprise pointolite, it is characterized in that: also comprise the first spectroscope, interior focusing object lens and differential confocal system; The first spectroscope, interior focusing object lens and measured lens are placed on the exit direction of light, the differential confocal system is placed on first spectroscopical reflection direction, measured lens surface with the first spectroscope with beam reflection to the differential confocal system, and coordinate differential confocal system to realize the accurate location on measured lens front surface summit and summit, measured lens rear surface.
6. differential confocal internal focusing method lens axis according to claim 5 and measurer for thickness is characterized in that: described differential confocal system comprises the second spectroscope, the first light intensity sensor and the second light intensity sensor; The light that is reflected by the first spectroscope enters the differential confocal system, by the second spectroscope, light is divided into two-way, and one the tunnel is radiated at and is positioned on the first defocused light intensity sensor, and another road is radiated on the second light intensity sensor that is positioned at before burnt.
7. differential confocal internal focusing method lens axis according to claim 5 and measurer for thickness is characterized in that: described differential confocal system also comprise the second spectroscope, burnt before pin hole, defocused pin hole, the first light intensity sensor and the second light intensity sensor; The light that is reflected by the first spectroscope enters the differential confocal system, by the second spectroscope, light is divided into two-way, leads up to after defocused pin hole, be radiated on the first light intensity sensor, another road by pin hole before burnt after, be radiated on the second light intensity sensor.
8. differential confocal internal focusing method lens axis according to claim 5 and measurer for thickness is characterized in that: described differential confocal system also comprise the second spectroscope, burnt before microcobjective, defocused microcobjective, the first light intensity sensor and the second light intensity sensor; Wherein the object plane of defocused microcobjective is positioned at defocusedly, places the first light intensity sensor at it as the plane, before the object plane of microcobjective is positioned at Jiao before burnt, places the second light intensity sensor at it as the plane; The light that is reflected by the first spectroscope enters the differential confocal system, by the second spectroscope, light is divided into two-way, and the defocused microcobjective of leading up to is imaged on the first light intensity sensor, and another road is imaged on the second light intensity sensor by microcobjective before burnt.
9. according to claim 5 or 6 or 7 or 8 described differential confocal internal focusing method lens axis and measurer for thickness, is characterized in that: comprise main control computer, electromechanical controlling device and AD acquisition module; Main control computer obtains the differential confocal signal that is gathered by light intensity sensor by the AD acquisition module; Main control computer is regulated the numerical aperture angle of interior focusing object lens emergent light by the controller controller for electric consumption, realize that differential confocal light cone summit moves along the scanning of optical axis direction.
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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106840001A (en) * 2017-01-16 2017-06-13 中国科学院上海光学精密机械研究所 The non-contact measurement apparatus and measuring method of optical lens center thickness
CN104154869B (en) * 2014-08-08 2017-10-03 中国科学院长春光学精密机械与物理研究所 White light interference lens center thickness measuring system and method
CN107941623A (en) * 2017-06-26 2018-04-20 重庆大学 A kind of experimental system using line array CCD imaging method measurement Young's modulus of elasticity
CN109579779A (en) * 2019-01-11 2019-04-05 哈尔滨工业大学 High-precision high-frequency rings anti-interference big working distance autocollimation and method
CN109855844A (en) * 2019-03-12 2019-06-07 苏州大学 A kind of optical lens centre deviation measuring device and method
CN113175894A (en) * 2021-04-21 2021-07-27 哈尔滨工程大学 Object surface three-dimensional shape white light interferometry device and method
CN113238369A (en) * 2021-07-12 2021-08-10 清华大学 High-resolution two-photon chromatographic microscope system and method based on electric focusing lens

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1527026A (en) * 2004-02-27 2004-09-08 哈尔滨工业大学 Differential confocal scanning detection method with high spatial resolution
CN101403650A (en) * 2008-11-21 2009-04-08 北京理工大学 Differential confocal combination ultra-long focal length measuring method and apparatus
CN101509828A (en) * 2009-03-06 2009-08-19 北京理工大学 Differential confocal-low coherent interference combination refractivity and thickness measurement method and apparatus
CN101526341A (en) * 2009-04-21 2009-09-09 北京理工大学 Differential confocal curvature radius measurement method and device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1527026A (en) * 2004-02-27 2004-09-08 哈尔滨工业大学 Differential confocal scanning detection method with high spatial resolution
CN101403650A (en) * 2008-11-21 2009-04-08 北京理工大学 Differential confocal combination ultra-long focal length measuring method and apparatus
CN101509828A (en) * 2009-03-06 2009-08-19 北京理工大学 Differential confocal-low coherent interference combination refractivity and thickness measurement method and apparatus
CN101526341A (en) * 2009-04-21 2009-09-09 北京理工大学 Differential confocal curvature radius measurement method and device

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
WEIQIAN ZHAO，JIUBIN TAN，LIRONG QIU: "Bipolar absolute differential confocal approach to higher spatial resolution", 《OPTICS EXPRESS》, vol. 12, no. 21, 26 September 2004 (2004-09-26) *
WEIQIAN ZHAO，RUODUAN SUN, LIRONG QIU，LIBO SHI，DINGGUO SHA: "Lenses axial space ray tracing measurement", 《OPTICS EXPRESS》, vol. 18, no. 4, 4 February 2010 (2010-02-04) *
鲁志辉: "红外物镜中心偏自动测试仪控制系统设计与实现", 《湖南工业职业技术学院学报》, vol. 7, no. 1, 31 March 2007 (2007-03-31) *

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104154869B (en) * 2014-08-08 2017-10-03 中国科学院长春光学精密机械与物理研究所 White light interference lens center thickness measuring system and method
CN106840001A (en) * 2017-01-16 2017-06-13 中国科学院上海光学精密机械研究所 The non-contact measurement apparatus and measuring method of optical lens center thickness
CN106840001B (en) * 2017-01-16 2019-02-01 中国科学院上海光学精密机械研究所 The non-contact measurement apparatus and measurement method of optical lens center thickness
CN107941623A (en) * 2017-06-26 2018-04-20 重庆大学 A kind of experimental system using line array CCD imaging method measurement Young's modulus of elasticity
CN109579779A (en) * 2019-01-11 2019-04-05 哈尔滨工业大学 High-precision high-frequency rings anti-interference big working distance autocollimation and method
CN109579779B (en) * 2019-01-11 2021-01-08 哈尔滨工业大学 High-precision high-frequency-response anti-interference large-working-distance auto-collimation device and method
CN109855844A (en) * 2019-03-12 2019-06-07 苏州大学 A kind of optical lens centre deviation measuring device and method
CN113175894A (en) * 2021-04-21 2021-07-27 哈尔滨工程大学 Object surface three-dimensional shape white light interferometry device and method
CN113175894B (en) * 2021-04-21 2023-09-29 哈尔滨工程大学 Object surface three-dimensional morphology white light interferometry device and method
CN113238369A (en) * 2021-07-12 2021-08-10 清华大学 High-resolution two-photon chromatographic microscope system and method based on electric focusing lens

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