CN113514426B - Device and method for measuring refractive index of spherical element medium - Google Patents

Device and method for measuring refractive index of spherical element medium Download PDF

Info

Publication number
CN113514426B
CN113514426B CN202111072337.XA CN202111072337A CN113514426B CN 113514426 B CN113514426 B CN 113514426B CN 202111072337 A CN202111072337 A CN 202111072337A CN 113514426 B CN113514426 B CN 113514426B
Authority
CN
China
Prior art keywords
spherical element
monochromatic light
element medium
wavelength
objective lens
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202111072337.XA
Other languages
Chinese (zh)
Other versions
CN113514426A (en
Inventor
不公告发明人
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Suzhou Gaoshi Semiconductor Technology Co ltd
Original Assignee
Suzhou Gaoshi Semiconductor Technology Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Suzhou Gaoshi Semiconductor Technology Co ltd filed Critical Suzhou Gaoshi Semiconductor Technology Co ltd
Priority to CN202111072337.XA priority Critical patent/CN113514426B/en
Publication of CN113514426A publication Critical patent/CN113514426A/en
Application granted granted Critical
Publication of CN113514426B publication Critical patent/CN113514426B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

The embodiment of the application discloses a device and a method for measuring the medium refractive index of a spherical element, wherein the measuring device comprises a spectrum confocal sensor, a spectrometer and a distance adjusting mechanism, and the spectrum confocal sensor comprises a white light point light source, a semi-transparent semi-reflecting mirror and a dispersion objective lens; the semi-transparent semi-reflecting mirror and the dispersion objective lens are sequentially arranged between the white light point light source and the detected spherical element medium along the optical axis; the distance adjusting mechanism drives the spectrum confocal sensor and the measured spherical element medium to be close to or far away from each other so that the distance between the dispersion objective lens and the measured spherical element medium changes 4 times along the optical axis; the spectrometer is opposite to the reflecting surface of the semi-transparent and semi-reflective mirror and is used for detecting the wavelengths of the upper surface and the lower surface focused and reflected on the detected spherical element medium; and calculating the refractive index curve of the detected spherical element medium according to the detected 5 different wavelengths. According to the invention, the method has the advantages of high detection efficiency and small error.

Description

Device and method for measuring refractive index of spherical element medium
Technical Field
The invention relates to the field of measurement of refractive index of transparent materials, in particular to a device and a method for measuring the refractive index of a spherical element medium.
Background
The refractive index is one of the basic parameters of optical materials, the refractive index of a medium decreases with the wavelength of incident light, and the difference in refractive index at different wavelengths is called dispersion. The research on the refractive index and the dispersion of the medium is significant for knowing the properties of the medium material and is an indispensable parameter in the design of an optical system, and the size of the medium directly influences the imaging quality of the system. The accurate obtaining of the refractive index of the optical material in the visible and near infrared bands is very important to the production, use and optical design of the optical material.
The high-precision refractive index measuring instrument adopts a precision angle measuring method, and utilizes a large-scale angle measuring instrument to realize the measurement of the refraction angle, thereby calculating the refractive index value. In general, the refractive index measurement method includes a minimum deviation angle method, an auto-collimation method, and the like. However, these methods require complicated operations and some require the material to be processed into a specific shape and size. However, in the actual optical system and optical lens, a large number of spherical elements are required, and these machined spherical elements sometimes need to be subjected to refractive index precision measurement for recheck before forming the lens or optical system, or the refractive index needs to be measured or calibrated when purchasing the spherical elements in stock. Therefore, the conventional detection method cannot effectively detect the target. Meanwhile, some conventional refractive index detection methods need to use more than 10 wavelength data, so that a large amount of measurement time is consumed, and the conventional method is a difficult problem in measuring the refractive index curve of the spherical element medium.
In view of the above, there is a need to develop a device and a method for measuring refractive index of spherical element medium, so as to solve the above problems.
Disclosure of Invention
The embodiment of the application provides a device and a method for measuring the refractive index of a spherical element medium, which can measure the refractive index of the spherical element medium with a certain thickness under different wavelengths, and have the advantages of high detection efficiency and small error.
In order to solve the above technical problem, an embodiment of the present application discloses the following technical solutions:
on one hand, the device for measuring the medium refractive index of the spherical element comprises a spectrum confocal sensor, a spectrometer and a distance adjusting mechanism, wherein the spectrum confocal sensor comprises a white light point light source, a semi-transparent semi-reflecting mirror and a dispersion objective lens; the semi-transparent semi-reflecting mirror and the dispersive objective lens are sequentially arranged between the white light point light source and the detected spherical element medium along the optical axis, the semi-transparent semi-reflecting mirror is close to the white light point light source, and the dispersive objective lens is close to the detected spherical element medium side; the distance adjusting mechanism drives the spectrum confocal sensor and the measured spherical element medium to be close to or far away from each other so that the distance between the dispersion objective lens and the measured spherical element medium changes 4 times along the optical axis; the spectrometer is opposite to the reflecting surface of the semi-transparent and semi-reflective mirror and is used for detecting the wavelength of the monochromatic light focused and reflected on the detected spherical element medium; if the upper and lower surfaces of the measured spherical element medium are spherical, substituting the detected 5 different wavelengths into a formula:
Figure 330288DEST_PATH_IMAGE001
calculating the refractive index of the measured spherical element medium under 5 wavelengths; if the opposite side surface of the detected spherical element medium and the dispersive objective lens is a plane, 5 different detected wavelengths are substituted into the formula:
Figure 716270DEST_PATH_IMAGE002
calculating the refractive index of the measured spherical element medium under 5 wavelengths; defining:
the central thickness of the spherical element medium is H;
the plurality of monochromatic lights decomposed by the dispersion objective lens are composed of at least one monochromatic light subset, and each monochromatic light subset comprises an upper monochromatic light and a lower monochromatic light; the upper monochromatic light in each monochromatic photon concentration is focused on the upper surface of the measured spherical element medium, and the lower monochromatic light in each monochromatic photon concentration is focused on the lower surface of the measured spherical element medium;
the wavelength of the lower monochromatic light in each monochromatic photon set is lambda;
the incident angle of the lower monochromatic light of each monochromatic photon concentration is
Figure 89483DEST_PATH_IMAGE003
；
The focal distance between the upper monochromatic light and the lower monochromatic light in each monochromatic photon concentration is
Figure 953533DEST_PATH_IMAGE004
；
Wherein,
Figure 862846DEST_PATH_IMAGE005
and
Figure 888571DEST_PATH_IMAGE006
is a known parameter of a dispersive objective lens in a spectral confocal sensor;
Figure 749079DEST_PATH_IMAGE007
is the curvature radius of the opposite side surface of the measured spherical element medium and the dispersive objective lens.
Optionally, defining:
when the distance between the dispersion objective lens and the measured spherical element medium is not changed, the wavelength of the upper monochromatic light is lambda1Wavelength of the lower monochromatic light is λ2；
When the distance between the dispersion objective lens and the measured spherical element medium is changed for the first time, the wavelength of the upper monochromatic light is lambda3Wavelength of the lower monochromatic light is λ4；
When the distance between the dispersion objective lens and the measured spherical element medium changes for the second time, the wavelength of the upper monochromatic light is lambda5Wavelength of the lower monochromatic light is λ6；
When the distance between the dispersion objective lens and the measured spherical element medium is changed for the third time, the wavelength of the upper monochromatic light is lambda7Wavelength of the lower monochromatic light is λ8；
When the distance between the dispersion objective lens and the measured spherical element medium is changed for the third time, the wavelength of the upper monochromatic light is lambda9Wavelength of the lower monochromatic light is λ10(ii) a Then the incident angle of each monochromatic light can be obtained
Figure 416821DEST_PATH_IMAGE008
And has the following components:
Figure 679175DEST_PATH_IMAGE009
，
according to refractive index
Figure 141380DEST_PATH_IMAGE010
And combining the formulas
Figure 489185DEST_PATH_IMAGE011
Calculating a refractive index curve of the detected spherical element medium;
wherein, X1、X2、X3、X4Is the wavelength term coefficient; A. b, C, D, E are constants to be solved.
Optionally, X is more than or equal to 3.51≤4, 4.5≤X2≤5, 5.5≤X3≤6, 0.1≤X4≤0.5。
In another aspect, a method for measuring refractive index of spherical element medium is provided, which comprises the following steps:
providing a measuring device, wherein the measuring device comprises a spectrum confocal sensor, a spectrometer and a distance adjusting mechanism, wherein the spectrum confocal sensor comprises a white light point light source, a semi-transparent semi-reflecting mirror and a dispersion objective lens; the semi-transparent semi-reflecting mirror and the dispersive objective lens are sequentially arranged between the white light point light source and the detected spherical element medium along the optical axis, the semi-transparent semi-reflecting mirror is close to the white light point light source, and the dispersive objective lens is close to the detected spherical element medium side;
the distance adjusting mechanism drives the spectrum confocal sensor and the measured spherical element medium to be close to or far away from each other so that the distance between the dispersion objective lens and the measured spherical element medium changes 4 times along the optical axis;
the spectrometer is arranged opposite to the reflecting surface of the semi-permeable and semi-reflective mirror and is used for detecting the wavelength of monochromatic light which is focused and reflected on the medium of the spherical element to be detected;
if the upper and lower surfaces of the measured spherical element medium are spherical, substituting the detected 5 different wavelengths into a formula:
Figure 695039DEST_PATH_IMAGE012
calculating the refractive index of the measured spherical element medium under 5 wavelengths; if the opposite side surface of the detected spherical element medium and the dispersive objective lens is a plane, 5 different detected wavelengths are substituted into the formula:
Figure 484003DEST_PATH_IMAGE013
calculating the refractive index of the measured spherical element medium under 5 wavelengths; defining:
the central thickness of the spherical element medium is H;
the plurality of monochromatic lights decomposed by the dispersion objective lens are composed of at least one monochromatic light subset, and each monochromatic light subset comprises an upper monochromatic light and a lower monochromatic light; the upper monochromatic light in each monochromatic photon concentration is focused on the upper surface of the measured spherical element medium, and the lower monochromatic light in each monochromatic photon concentration is focused on the lower surface of the measured spherical element medium;
the wavelength of the lower monochromatic light in each monochromatic photon set is lambda;
the incident angle of the lower monochromatic light of each monochromatic photon concentration is
Figure 206190DEST_PATH_IMAGE014
；
The focal distance between the upper monochromatic light and the lower monochromatic light in each monochromatic photon concentration is
Figure 713395DEST_PATH_IMAGE015
；
Wherein,
Figure 581994DEST_PATH_IMAGE016
and
Figure 694307DEST_PATH_IMAGE017
is a known parameter of a dispersive objective lens in a spectral confocal sensor;
Figure 622948DEST_PATH_IMAGE018
is the curvature radius of the opposite side surface of the measured spherical element medium and the dispersive objective lens.
Optionally, defining:
when the distance between the dispersion objective lens and the measured spherical element medium is not changed, the wavelength of the upper monochromatic light is lambda1Wavelength of the lower monochromatic light is λ2；
When the distance between the dispersion objective lens and the measured spherical element medium is changed for the first time, the wavelength of the upper monochromatic light is lambda3Wavelength of the lower monochromatic light is λ4；
When the distance between the dispersion objective lens and the measured spherical element medium changes for the second time, the wavelength of the upper monochromatic light is lambda5Wavelength of the lower monochromatic light is λ6；
When the distance between the dispersion objective lens and the measured spherical element medium is changed for the third time, the wavelength of the upper monochromatic light is lambda7Wavelength of the lower monochromatic light is λ8；
When the distance between the dispersion objective lens and the measured spherical element medium is changed for the third time, the wavelength of the upper monochromatic light is lambda9Wavelength of the lower monochromatic light is λ10(ii) a Then the incident angle of each monochromatic light can be obtained
Figure 820711DEST_PATH_IMAGE019
And has the following components:
Figure 493001DEST_PATH_IMAGE020
，
according to refractive index
Figure 459820DEST_PATH_IMAGE021
And combining the formulas
Figure 60828DEST_PATH_IMAGE022
Calculating a refractive index curve of the detected spherical element medium;
wherein, X1、X2、X3、X4Is the wavelength term coefficient; A. b, C, D, E are constants to be solved.
Optionally, X is more than or equal to 3.51≤4, 4.5≤X2≤5, 5.5≤X3≤6, 0.1≤X4≤0.5。
One of the above technical solutions has the following advantages or beneficial effects: the refractive index of a spherical element medium with a certain thickness under different wavelengths can be measured, and the refractive index measurement under 5 different wavelengths can be rapidly realized only by changing the distance between the dispersion objective and the measured spherical element medium for 4 times along the optical axis, so that the problem that the refractive index curve of the spherical element is difficult to measure is solved.
One of the above technical solutions has the following advantages or beneficial effects: the refractive index curve of the detected spherical element medium can be calculated by only utilizing the refractive indexes obtained under 5 different wavelengths, and the method has the advantages of high detection efficiency and small error.
Drawings
In order to more clearly illustrate the technical solution of the embodiments of the present invention, the drawings of the embodiments will be briefly described below, and it is apparent that the drawings in the following description relate only to some embodiments of the present invention and are not limiting thereof, wherein:
FIG. 1 is a front view of a device for measuring the refractive index of a spherical element medium according to an embodiment of the present invention;
FIG. 2 is a schematic diagram and an optical path structure of a device for measuring a refractive index of a spherical element medium according to an embodiment of the present invention;
fig. 3 is a schematic diagram of the principle of dispersion of a spectral confocal sensor in a measuring device for refractive index of a spherical element medium according to an embodiment of the present invention;
FIG. 4 is a six type of spherical element;
fig. 5 is a schematic diagram of a spectral confocal sensor in a measuring apparatus for refractive index of spherical element medium according to an embodiment of the present invention for measuring refractive index of biconvex element medium at current wavelength;
fig. 6 is a schematic diagram of a spectral confocal sensor in a measuring apparatus for refractive index of spherical element medium according to an embodiment of the present invention for measuring refractive index of biconcave element medium at current wavelength;
fig. 7 is a schematic diagram of a spectral confocal sensor in a device for measuring the refractive index of a spherical element medium according to an embodiment of the present invention to measure the refractive index of a plano-convex element medium at a current wavelength;
FIG. 8 is a schematic diagram showing the change of the focal length of the dispersive objective lens L from 350-1100 nm;
FIG. 9 is a diagram comparing the exit angle of the dispersion lens light with the wavelength curve and the collected data calculated by using a formula;
FIG. 10 is a plot of chromatic dispersion lens back intercept position versus wavelength curve versus acquired data calculated using a formula;
FIG. 11 is a graph of refractive index profile error for BAM23 material calculated using the refractive index equation of the present invention;
FIG. 12 is a graph of the refractive index profile error for a PBH55 material calculated using the refractive index formula of the present invention;
fig. 13 is a flow chart illustrating a method for measuring the refractive index of a spherical element medium according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
In the drawings, the shape and size may be exaggerated for clarity, and the same reference numerals will be used throughout the drawings to designate the same or similar components.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and similar terms in the description and claims of the present application do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. Also, the use of the terms "a," "an," or "the" and similar referents do not denote a limitation of quantity, but rather denote the presence of at least one. The word "comprise" or "comprises", and the like, means that the element or item listed before "comprises" or "comprising" covers the element or item listed after "comprising" or "comprises" and its equivalents, and does not exclude other elements or items. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.
In the following description, terms such as center, thickness, height, length, front, back, rear, left, right, top, bottom, upper, lower, etc., are defined with respect to the configurations shown in the respective drawings, and in particular, "height" corresponds to a dimension from top to bottom, "width" corresponds to a dimension from left to right, "depth" corresponds to a dimension from front to rear, which are relative concepts, and thus may be varied accordingly depending on the position in which it is used, and thus these or other orientations should not be construed as limiting terms.
Terms concerning attachments, coupling and the like (e.g., "connected" and "attached") refer to a relationship wherein structures are secured or attached, either directly or indirectly, to one another through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise.
Example 1
Fig. 1 to 13 show embodiment 1 of the present invention, and with reference to fig. 1 to 8, it can be seen that the device 1 for measuring the refractive index of a spherical element medium includes a spectral confocal sensor 11, a spectrometer 14 and a distance adjustment mechanism, where the spectral confocal sensor 11 includes a white light point light source S, a semi-transparent half-mirror X and a dispersive objective lens L; the semi-transparent semi-reflecting mirror X and the dispersive objective lens L are sequentially arranged between the white light point light source S and the spherical element medium 13 to be measured along the optical axis, the semi-transparent semi-reflecting mirror X is close to the white light point light source S, and the dispersive objective lens L is close to the spherical element medium 13 side to be measured; the distance adjusting mechanism drives the spectral confocal sensor 11 and the measured spherical element medium 13 to be close to or far away from each other so that the distance between the dispersive objective lens L and the measured spherical element medium 13 changes 4 times along the optical axis; the spectrometer 14 is opposite to the reflecting surface of the semi-permeable and semi-reflective mirror X and is used for detecting the wavelength of the monochromatic light focused and reflected on the detected spherical element medium 13; and calculating the refractive index curve of the detected spherical element medium 13 according to the detected 5 different wavelengths. In the present embodiment, the spherical element medium 13 to be measured is placed on the platform 12 below the dispersive objective lens L, and the distance between the dispersive objective lens L and the spherical element medium 13 to be measured can be adjusted by lifting the platform 12 or the spectral confocal sensor 11. Referring to fig. 2, fig. 2 shows a light path schematic diagram of a spectral confocal sensor 11, which is an optical system that produces an image S' of a point source S on the surface of a medium, the backscattered light being collected by the same optical system that is imaged at a pinhole S ″.
The pinhole S "is placed in front of the spectrometer 14 so that light of a particular wavelength reflected back by the surface of the medium can pass through and light of wavelengths elsewhere is blocked, so it is also referred to as a" spatial filter ". The spectral confocal sensor is characterized by a special signal-to-noise ratio. According to the principle of spectral confocal, the optical system is a dispersive lens. The spectrometer signal exhibits a spectral peak corresponding to the spectral redistribution of the collected light. The spectral peak on the spectrometer changes as the medium is displaced within the measurement range. The detected spherical element medium 13 in this embodiment may be a glass material, a crystal material, a transparent film material, a liquid crystal material, a transparent liquid material, or a transparent plastic material with this characteristic.
Referring again to fig. 4, the spherical elements may be divided into 6 types in total, which are planoconvex, planoconcave, biconvex, positive meniscus, negative meniscus, and biconcave, respectively.
Referring again to fig. 5-6, if the spherical element medium under test is bi-convex, positive meniscus, negative meniscus and bi-concave, define:
the central thickness of the spherical element medium is H;
the plurality of monochromatic lights decomposed by the dispersion objective lens L are composed of at least one monochromatic light subset, and each monochromatic light subset comprises an upper monochromatic light and a lower monochromatic light; the upper monochromatic light in each monochromatic photon concentration is focused on the upper surface of the measured spherical element medium 13, and the lower monochromatic light in each monochromatic photon concentration is focused on the lower surface of the measured spherical element medium 13;
the wavelength of the lower monochromatic light in each monochromatic photon set is lambda;
the incident angle of the lower monochromatic light of each monochromatic photon concentration is
Figure 480308DEST_PATH_IMAGE023
；
The focal distance between the upper monochromatic light and the lower monochromatic light in each monochromatic photon concentration is
Figure 956289DEST_PATH_IMAGE024
(ii) a The refractive index of the measured spherical element medium 13 at the wavelength λ
Figure 777614DEST_PATH_IMAGE025
Is derived from the following formula:
Figure 313638DEST_PATH_IMAGE026
，
wherein,
Figure 17152DEST_PATH_IMAGE027
and
Figure 906610DEST_PATH_IMAGE028
is a known parameter of the dispersive objective lens L in the spectroscopic confocal sensor 11;
Figure 972655DEST_PATH_IMAGE029
is the curvature radius of the opposite side surface of the measured spherical element medium and the dispersive objective lens.
In the formula only
Figure 554946DEST_PATH_IMAGE030
Is unknown, and the other quantities are known or measured, so that it is possible to calculate
Figure 575117DEST_PATH_IMAGE030
。
Referring again to FIG. 7, if the measured spherical element medium is planoconvex and planoconcave, the refractive index of the measured spherical element medium 13 at the wavelength λ
Figure 268267DEST_PATH_IMAGE030
Is derived from the following formula:
Figure 657660DEST_PATH_IMAGE031
。
the dispersive objective lens L in the spectral confocal sensor is a core optical component, an important index in the dispersive objective lens is the degree of dispersion, namely, the distance between focuses with different wavelengths, the step that the usable wavelength of the dispersive objective lens designed in the embodiment is 350-1100 nm needs to be carried out by matching with a spectrometer, and the dispersive distance of the dispersive objective lens L designed in the embodiment in the wave band of 350-1100 nm is 108 mm. FIG. 9 shows a schematic diagram of the variation of the focal length of the dispersive objective lens L from 350 to 1100nm, in which the focal length at the leftmost end is 350nm and the focal length at the rightmost end is 1100 nm. Specific parameters of the dispersive objective lens are given in table 1, and the relationship data between the wavelength of the dispersive objective lens L and the position of the rear intercept, which is the distance from the last surface of the lens to the focal point, is given in table 2:
table 1 dispersive objective lens parameters
-369.618 15 SF5
797.370 7
-488.393 18 LASFN31
-149.540 1.5
286.893 20 LASFN31
-312.027 2
173.887 18 SF5
612.929 10
-2516.018 12 LASFN31
215.297 11.23
81.443 16 SF5
72.519 201.089
TABLE 2 wavelength and rear intercept position (unit: mm) of dispersive objective
Wavelength (nm) 350 400 500 600 700 800 900 1000 1100
Rear intercept (mm) 201.09 225 255.64 273.85 285.67 293.94 300.12 305 309.07
Further, the dispersive objective lens L is a lens with large dispersion and large NA, and since the focal positions are different for different wavelengths, the corresponding angles are different, but it can be expressed by apochromatic property formula (ACF formula). The formula of the exit angle and the wavelength of the marginal ray of the dispersive objective lens L is given as follows:
Figure 410852DEST_PATH_IMAGE032
（1），
in the present embodiment, there is defined:
Aθ=5.80125181；
Bθ=259436.175；
Cθ=2482754578937；
Dθ=-0.0001707953；
substituting equation (1) yields:
Figure 416854DEST_PATH_IMAGE033
，
fig. 9 is a light exit angle curve of the dispersion lens, in which a circle is collected data, a solid line is a curve calculated by solving the formula (1) using 500nm, 600nm, 700nm, and 800nm, and the collected data and the calculated curve have a good fit, which indicates that the light exit angle at any wavelength within 350 to 1100nm can be calculated by using an ACF formula
Figure 913695DEST_PATH_IMAGE034
。
The same reasoning gives the formula of the back intercept and the wavelength:
Figure 688753DEST_PATH_IMAGE035
given in this example:
Al=305.31355503；
Bl=-14679661.111；
Cl=60295422216018.2；
Dl=0.0142284985130074；
further, it is found that:
Figure 347267DEST_PATH_IMAGE036
，
similarly, FIG. 10 is a plot of back intercept position versus wavelength, where the circle is the collected data and the solid line is the curve calculated by solving the ACF equation using 500nm, 600nm, 700nm, and 800nm, the collected numberAccording to the good goodness of fit with the calculated curve, the back intercept at any wavelength within 350-1100 nm can be calculated by using an ACF formula
Figure 512669DEST_PATH_IMAGE037
。
The distance between any two wavelengths in the return-spectrum confocal system can be obtained by the following equation:
Figure 173720DEST_PATH_IMAGE038
（2），
when the center thickness H of the spherical element medium is larger, the first surface has a spherical radius r1When known, is according to
Figure 944230DEST_PATH_IMAGE039
（3），
Calculated by the formula (3)
Figure 898279DEST_PATH_IMAGE040
。
Or the central thickness H of the spherical element medium, and the first face being a plane, according to
Figure 82136DEST_PATH_IMAGE041
（4），
Calculated by the formula (4)
Figure 920779DEST_PATH_IMAGE042
。
Specifically, referring to fig. 5 to 7, there are defined:
when the distance between the dispersion objective lens L and the measured spherical element medium 13 is not changed, the wavelength of the upper monochromatic light is lambda1Wavelength of the lower monochromatic light is λ2；
When the distance between the dispersion objective lens L and the measured spherical element medium 13 is changed for the first time, the wavelength of the upper monochromatic light is lambda3Wavelength of the lower monochromatic light is λ4；
When the distance between the dispersion objective lens L and the measured spherical element medium 13 changes for the second time, the wavelength of the upper monochromatic light is lambda5Wavelength of the lower monochromatic light is λ6；
When the distance between the dispersion objective lens L and the measured spherical element medium 13 changes for the third time, the wavelength of the upper monochromatic light is lambda7Wavelength of the lower monochromatic light is λ8(ii) a When the distance between the dispersion objective lens and the measured spherical element medium is changed for the third time, the wavelength of the upper monochromatic light is lambda9Wavelength of the lower monochromatic light is λ10(ii) a Then the incident angle of each monochromatic light can be obtained
Figure 404850DEST_PATH_IMAGE043
And has the following components:
Figure 670746DEST_PATH_IMAGE044
，
according to refractive index
Figure 368663DEST_PATH_IMAGE045
Is calculated by the formula (2)
Figure 276576DEST_PATH_IMAGE046
And in combination with the formula:
Figure 83995DEST_PATH_IMAGE047
（5），
calculating the refractive index curve of the measured spherical element medium 13, wherein X is more than or equal to 3.51≤4, 4.5≤X2≤5, 5.5≤X3≤6, 0.1≤X4≤0.5。
Further, the error of OHARA glass library material was verified using equation (5), where X1=4, X2=5, X3=6, X4=0.2, maximum and minimum error data in the 400-1100 nm band using the wavelength of 400nm, 560nm, 680nm, 800nm, 1100nm solving curves are shown in table 3, and fig. 11 and 12 are graphs obtained by calculating BAM23 and PB using the formula (5)Refractive index profile error plot for H55 material (corresponding to table 3).
TABLE 3 calculation of 400-1100 nm refractive index error using equation (5)
Material Maximum error (%) Minimum error (%)
APL1 0.001626 -0.00879
BAH13 0.000809 -0.00077
BAH22 0.002685 -3.4E-05
BAH26 0.000839 -6.3E-05
BAH30 0.001901 -3.6E-05
BAH32 0.002246 -4.1E-05
BAH54 0.000898 -0.00071
BAH71 0.001069 -5.7E-05
BAH77 0.00073 -0.00011
BAH78 0.000939 -6.7E-05
BAL15 0.001358 -0.00606
BAL15Y 0.001318 -0.00493
BAL35Y 0.001495 -0.00622
BAL42 0.001338 -0.00585
BAL5 0.001068 -0.00342
BAL50 0.001481 -0.00704
BAL7 0.000924 -0.00261
BAM21 0.000738 -0.0003
BAM23 0.000827 -6.8E-05
BAM3 0.000815 -0.0009
BAM5 0.000908 -0.00193
BAM8 0.000986 -0.00242
BAM9 0.000835 -0.00107
BPH35 0.001413 -0.00457
BPH40 0.00127 -0.00342
BPH45 0.001397 -7.5E-05
BPH5 0.001441 -0.00403
BPH50 0.002192 -4.7E-05
BPH8 0.001014 -0.0005
BPM4 0.001601 -0.00646
BPM51 0.001653 -0.00607
BSL1 0.001437 -0.0066
BSL21 0.001629 -0.0084
BSL22 0.001264 -0.00463
BSL3 0.001807 -0.00971
BSL7 0.001486 -0.00688
BSL7Y 0.001758 -0.00855
BSM16C 0.001515 -0.00707
BSM18 0.001295 -0.00514
BSM22 0.000926 -0.00187
BSM23 0.001091 -0.00371
BSM24 0.000791 -0.00091
BSM36 0.001683 -0.00795
BSM51Y 0.001447 -0.0059
BSM6 0.00105 -0.00331
BSM7 0.001289 -0.00545
BSM71 0.000822 -0.00098
BSM81 0.002055 -0.01077
BSM9 0.000994 -0.00247
FPL51 0.00086 -0.00349
FPL52 0.000909 -0.00461
FPL53 0.000637 -0.00215
FSL3 0.001559 -0.00788
FSL5 0.001804 -0.01033
FTL8 0.001667 -0.00937
FTM16 0.001118 -0.00371
FTM8 0.001234 -0.00495
LAH51 0.001205 -0.00282
LAH52 0.001278 -0.00281
LAH53 0.001111 -0.00172
LAH54 0.001219 -0.00259
LAH55 0.001102 -0.00155
LAH58 0.001795 -6.3E-05
LAH59 0.001098 -0.00202
LAH60 0.001024 -0.00094
LAH63 0.001069 -0.0013
LAH64 0.00133 -0.00355
LAH65 0.001306 -0.00343
LAH66 0.001419 -0.00456
LAH67 0.001361 -0.00376
LAH71 0.002044 -4.8E-05
LAH75 0.000913 -0.00032
LAH78 0.003223 -3.8E-05
LAL10 0.001148 -0.00318
LAL11 0.001418 -0.00607
LAL12 0.002351 -4.3E-05
LAL13 0.001557 -0.00642
LAL14 0.001722 -0.00746
LAL18 0.001723 -0.00742
LAL52 0.001559 -0.00703
LAL54 0.001281 -0.00486
LAL56 0.001051 -0.0031
LAL58 0.000912 -0.00126
LAL59 0.001598 -0.0065
LAL60 0.001717 -0.00725
LAL61 0.001579 -0.00592
LAL7 0.001541 -0.00682
LAL8 0.001682 -0.00728
LAL9 0.00144 -0.00507
LAM2 0.000787 -0.00031
LAM3 0.000807 -0.00061
LAM54 0.001647 -0.00664
LAM55 0.000854 -0.00056
LAM58 0.002684 -3E-05
LAM59 0.000904 -0.00105
LAM60 0.001539 -0.00589
LAM61 0.001526 -5.1E-05
LAM66 0.001184 -0.00243
LAM7 0.005136 -0.00015
L-BAL35 0.001676 -0.00766
L-BAL35P 0.001678 -0.00761
L-BAL42 0.001341 -0.00527
L-BAL42P 0.001321 -0.00506
L-BAL43 0.001376 -0.00549
L-BBH1 0.004225 -0.00162
L-BBH2 0.008222 -0.001
L-BSL7 0.001734 -0.00852
L-LAH53 0.000942 -0.00035
L-LAH81 0.000886 -0.00017
L-LAH83 0.002582 -5E-05
L-LAH84 0.00148 -7.3E-05
L-LAH84P 0.00177 -6.2E-05
L-LAH85 0.001466 -7.9E-05
L-LAH86 0.004278 -9E-05
L-LAH87 0.000848 -0.00034
L-LAH90 0.001335 -7.6E-05
L-LAH91 0.001226 -0.00278
L-LAL12 0.001432 -0.00511
L-LAL13 0.001345 -0.00427
L-LAL15 0.001634 -0.00623
L-LAM60 0.001194 -0.00271
L-LAM69 0.001101 -0.00165
L-LAM72 0.001358 -0.00381
L-NBH54 0.006268 -0.00021
L-PHL1 0.000939 -0.00261
L-PHL2 0.001055 -0.00353
NSL33 0.001026 -0.00333
NSL7 0.001265 -0.00533
PBH1 0.007143 -0.00025
PBH10 0.004774 -0.00013
PBH11 0.005801 -0.0002
PBH11W 0.005801 -0.0002
PBH13 0.005002 -0.00015
PBH13W 0.005002 -0.00015
PBH14 0.00121 -4.2E-05
PBH14W 0.00121 -4.2E-05
PBH18 0.003724 -9.1E-05
PBH23 0.004669 -0.00015
PBH23W 0.004669 -0.00015
PBH25 0.0046 -0.00014
PBH3 0.008126 -0.0003
PBH3W 0.004738 -0.00014
PBH4 0.006539 -0.00022
PBH4W 0.006539 -0.00022
PBH53 0.009512 -0.00037
PBH53W 0.009512 -0.00037
PBH55 0.012253 -0.00064
PBH56 0.011837 -0.00057
PBH6 0.004783 -0.00015
PBH6W 0.004783 -0.00015
PBH71 0.01459 -0.00104
PBH72 0.010948 -0.00058
PBL1 0.000653 -0.00015
PBL1Y 0.000956 -0.00177
PBL2 0.000995 -0.0029
PBL21 0.001108 -0.00383
PBL22 0.002637 -3E-05
PBL25 0.001072 -0.00316
PBL25Y 0.000865 -0.0005
PBL26 0.000785 -0.00064
PBL26Y 0.000925 -0.00109
PBL27 0.000906 -0.00192
PBL35Y 0.000817 -0.0003
PBL6 0.000793 -0.00119
PBL6Y 0.001127 -0.0032
PBL7 0.001069 -0.00355
PBM1 0.00086 -0.00124
PBM11 0.001336 -0.0052
PBM18Y 0.000813 -0.00015
PBM2 0.000816 -0.00095
PBM22 0.002805 -4E-05
PBM25 0.003361 -6.6E-05
PBM27 0.00326 -5.8E-05
PBM28 0.005886 -0.00018
PBM28W 0.005886 -0.00018
PBM2Y 0.002237 -4.1E-05
PBM3 0.002131 -4E-05
PBM35 0.000942 -0.00229
PBM39 0.001174 -5.7E-05
PBM4 0.000733 -0.00029
PBM5 0.000707 -0.00025
PBM6 0.002122 -3.5E-05
PBM8 0.001425 -4.9E-05
PBM8Y 0.00089 -0.00032
PBM9 0.000765 -0.00039
PHM51 0.001338 -0.00557
PHM52 0.001013 -0.00331
PHM53 0.001208 -0.005
S-APL1 0.001626 -0.00879
S-BAH10 0.000951 -0.00137
S-BAH11 0.000886 -0.00108
S-BAH27 0.000903 -0.00083
S-BAH32 0.000909 -0.00091
S-BAH54 0.000898 -0.00071
S-BAL11 0.001247 -0.00456
S-BAL12 0.001191 -0.00445
S-BAL14 0.001182 -0.00405
S-BAL2 0.00095 -0.00212
S-BAL22 0.001612 -0.00737
S-BAL3 0.000932 -0.00215
S-BAL35 0.001425 -0.00587
S-BAL41 0.001403 -0.00581
S-BAL42 0.001254 -0.00467
S-BAL50 0.001481 -0.00704
S-BAM12 0.000988 -0.00171
S-BAM3 0.000957 -0.00202
S-BAM4 0.0008 -0.0007
S-BSL7 0.001623 -0.00784
S-BSM10 0.001145 -0.00355
S-BSM14 0.001407 -0.00567
S-BSM15 0.001279 -0.00461
S-BSM16 0.001406 -0.00562
S-BSM18 0.001065 -0.00283
S-BSM2 0.001022 -0.00284
S-BSM21 0.001096 -0.00307
S-BSM22 0.001059 -0.0028
S-BSM25 0.00094 -0.00158
S-BSM28 0.000982 -0.00207
S-BSM4 0.001168 -0.00387
S-BSM71 0.001065 -0.00275
S-BSM81 0.001977 -0.00941
S-BSM9 0.001091 -0.00312
S-BSM93 0.001424 -0.00608
S-FPL51 0.00075 -0.00254
S-FPL51Y 0.000692 -0.0021
S-FPL52 0.000763 -0.00299
S-FPL53 0.000645 -0.0024
S-FPL55 0.000675 -0.00261
S-FPM2 0.0007 -0.00126
S-FPM3 0.000839 -0.00272
S-FSL5 0.001664 -0.00851
S-FSL5Y 0.001642 -0.00834
S-FTL10 0.001282 -0.0052
S-FTM16 0.000855 -0.00086
S-LAH51 0.001108 -0.00152
S-LAH52 0.001017 -0.00083
S-LAH52Q 0.001349 -6.9E-05
S-LAH53 0.000992 -0.00055
S-LAH53V 0.001054 -7.6E-05
S-LAH54 0.001219 -0.00259
S-LAH55 0.001102 -0.00112
S-LAH55V 0.001021 -0.00072
S-LAH55VS 0.000936 -0.00032
S-LAH58 0.002698 -4.8E-05
S-LAH59 0.001013 -0.00097
S-LAH60 0.001227 -8E-05
S-LAH60MQ 0.003991 -7.7E-05
S-LAH60V 0.001884 -6.1E-05
S-LAH63 0.00099 -0.00054
S-LAH63Q 0.001988 -5.4E-05
S-LAH64 0.00133 -0.0033
S-LAH65 0.001293 -0.00289
S-LAH65V 0.001282 -0.00275
S-LAH65VS 0.001106 -0.00159
S-LAH66 0.001443 -0.0043
S-LAH67 0.001361 -0.00376
S-LAH71 0.006339 -0.0002
S-LAH96 0.000967 -0.00111
S-LAH97 0.001535 -0.00527
S-LAL10 0.001303 -0.00362
S-LAL11 0.001418 -0.00607
S-LAL12 0.001246 -0.00385
S-LAL13 0.001517 -0.00548
S-LAL14 0.001766 -0.00741
S-LAL18 0.001697 -0.00667
S-LAL19 0.00168 -0.0065
S-LAL20 0.001376 -5.2E-05
S-LAL21 0.000917 -0.00132
S-LAL52 0.001559 -0.00703
S-LAL54 0.001209 -0.00386
S-LAL54Q 0.001667 -0.00696
S-LAL56 0.00102 -0.00202
S-LAL58 0.000892 -0.00108
S-LAL59 0.00151 -0.00507
S-LAL60 0.001717 -0.00725
S-LAL61 0.001631 -0.00602
S-LAL7 0.00145 -0.00562
S-LAL7Q 0.001876 -0.00848
S-LAL8 0.001611 -0.00608
S-LAL9 0.001636 -0.00644
S-LAM2 0.00077 -0.00012
S-LAM3 0.000855 -0.00062
S-LAM51 0.000933 -0.0012
S-LAM52 0.000741 -0.00011
S-LAM54 0.001503 -0.00468
S-LAM55 0.001057 -7.2E-05
S-LAM58 0.001105 -6.7E-05
S-LAM59 0.000954 -0.00131
S-LAM60 0.001499 -0.00479
S-LAM61 0.000931 -0.00096
S-LAM66 0.000953 -0.00032
S-NBH5 0.001194 -0.00256
S-NBH51 0.000943 -0.00029
S-NBH52 0.000918 -0.0005
S-NBH52V 0.001119 -0.00175
S-NBH53 0.00164 -6.4E-05
S-NBH53V 0.00145 -7.2E-05
S-NBH8 0.000865 -0.0001
S-NBM51 0.001388 -0.00447
S-NSL2 0.001211 -0.00468
S-NSL3 0.001166 -0.00439
S-NSL36 0.001194 -0.00429
S-NSL5 0.001335 -0.00557
S-PHM51 0.001338 -0.00557
S-PHM52 0.001012 -0.00306
S-PHM53 0.001194 -0.00448
SSL2 0.001349 -0.00514
SSL5 0.00169 -0.00856
S-TIH20 0.002353 -3.5E-05
S-TIL1 0.001045 -0.00281
S-TIL2 0.001085 -0.00316
S-TIL25 0.001022 -0.00212
S-TIL26 0.001033 -0.00241
S-TIL27 0.001038 -0.00236
S-TIL6 0.001141 -0.00361
S-TIM1 0.000818 -0.00042
S-TIM2 0.000846 -0.00061
S-TIM3 0.000889 -0.00096
S-TIM5 0.000898 -0.001
S-TIM6 0.000757 -0.00011
S-TIM8 0.000895 -0.00111
S-YGH51 0.001578 -0.00551
S-YGH52 0.001494 -0.00531
TIH11 0.002217 -3.6E-05
TIH14 0.001503 -5.5E-05
TIH23 0.001595 -4.9E-05
TIH53 0.00325 -6.9E-05
TIH6 0.004877 -0.00014
TIM11 0.001336 -0.0052
TPH55 0.000799 -0.00019
YGH51 0.001603 -0.00624
YGH52 0.001494 -0.00531
As can be seen from Table 3, the maximum absolute error is not more than 0.015%, the maximum average error is 0.001806% (the average value of the maximum errors of all glass materials in Table 3), and the minimum average error is-0.00282%, which shows that the refractive index of OHARA glass measured by using the formula (5) in the range of 400-1100 nm has smaller errors, and can better meet the requirements of engineering practice.
Mixing X1, X2, X3, X4The average maximum error and average minimum error of the refractive index of OHARA glass library material are calculated by formula (5) using other coefficients and using 400, 560, 680, 800 and 1100nm as well (X in this case) as shown in Table 41, X2, X3, X4Only some of the values are listed, but do not affect the understanding of the present solution):
TABLE 4 calculation of 400-1100 nm fold using different coefficientsError of refractive index
X1 X1 X1 X1 Mean maximum error (%) Mean minimum error (%)
4 5 6 0.1 0.001652 -0.00387
4 5 5.1 0.9 0.00432 -0.00028
4 4.9 5.8 0.4 0.002133 -0.00145
3.9 5 5.7 0.3 0.001579 -0.00228
3.5 4.7 6 1 0.003741 -0.00026
3.5 4.3 6 1.7 0.007642 -0.00087
3.4 4.8 5.8 1.4 0.006155 -0.00051
3.3 4.9 5.7 1.7 0.006155 -0.00051
And (4) conclusion: in the embodiment, a spectrum confocal system is used, the refractive index of a certain spherical element medium material can be measured without complicated steps according to the characteristics of a dispersion lens, and then the whole refractive index curve can be rapidly calculated through a formula (5) according to the measured 5 refractive index data with any wavelength, wherein the refractive index for measuring a single wavelength is faster than that of the conventional method, and the refractive index curve is calculated by using less refractive index data (other formulas need more data), so the detection process is very rapid.
Example 2
Fig. 1 to 13 also show embodiment 2 of the present invention, and embodiment 2 differs from embodiment 1 in that:
a method for measuring the refractive index of a spherical element medium is provided, which comprises the following steps:
providing a measuring device, wherein the measuring device comprises a spectrum confocal sensor, a spectrometer and a distance adjusting mechanism, wherein the spectrum confocal sensor comprises a white light point light source, a semi-transparent semi-reflecting mirror and a dispersion objective lens; the semi-transparent and semi-reflective mirror (X) and the dispersive objective lens are sequentially arranged between the white light point light source and the detected spherical element medium along an optical axis, the semi-transparent and semi-reflective mirror (X) is close to the white light point light source, and the dispersive objective lens is close to the detected spherical element medium side;
the distance adjusting mechanism drives the spectrum confocal sensor and the measured spherical element medium to be close to or far away from each other so that the distance between the dispersion objective lens and the measured spherical element medium changes 4 times along the optical axis;
the spectrometer is arranged opposite to the reflecting surface of the semi-permeable and semi-reflective mirror and is used for detecting the wavelength of monochromatic light which is focused and reflected on the medium of the spherical element to be detected;
the detected 5 different wavelengths are used according to the formula:
Figure 645426DEST_PATH_IMAGE048
calculating the refractive index of the measured spherical element medium at 5 wavelengths, and defining:
the central thickness of the spherical element medium is H;
the plurality of monochromatic lights decomposed by the dispersion objective lens are composed of at least one monochromatic light subset, and each monochromatic light subset comprises an upper monochromatic light and a lower monochromatic light; the upper monochromatic light in each monochromatic photon concentration is focused on the upper surface of the measured spherical element medium, and the lower monochromatic light in each monochromatic photon concentration is focused on the lower surface of the measured spherical element medium;
the wavelength of the lower monochromatic light in each monochromatic photon set is lambda;
the incident angle of the lower monochromatic light of each monochromatic photon concentration is
Figure 210400DEST_PATH_IMAGE049
；
The focal distance between the upper monochromatic light and the lower monochromatic light in each monochromatic photon concentration is
Figure 515479DEST_PATH_IMAGE050
；
Wherein,
Figure 849509DEST_PATH_IMAGE051
and
Figure 83306DEST_PATH_IMAGE052
is a known parameter of a dispersive objective lens in a spectral confocal sensor;
Figure 135576DEST_PATH_IMAGE053
is a measured spherical element medium andradius of curvature of opposite side surfaces of the dispersive objective lens.
If the surface of the spherical element medium to be measured opposite to the dispersion objective lens is a plane, the refractive index of the spherical element medium to be measured 13 at the wavelength λ is set to be a refractive index
Figure 978767DEST_PATH_IMAGE054
Is derived from the following formula:
Figure 432882DEST_PATH_IMAGE055
further, defining:
when the distance between the dispersion objective lens L and the measured spherical element medium 13 is not changed, the wavelength of the upper monochromatic light is lambda1Wavelength of the lower monochromatic light is λ2；
When the distance between the dispersion objective lens L and the measured spherical element medium 13 is changed for the first time, the wavelength of the upper monochromatic light is lambda3Wavelength of the lower monochromatic light is λ4；
When the distance between the dispersion objective lens L and the measured spherical element medium 13 changes for the second time, the wavelength of the upper monochromatic light is lambda5Wavelength of the lower monochromatic light is λ6；
When the distance between the dispersion objective lens L and the measured spherical element medium 13 changes for the third time, the wavelength of the upper monochromatic light is lambda7Wavelength of the lower monochromatic light is λ8；
When the distance between the dispersion objective lens L and the measured spherical element medium 13 changes for the third time, the wavelength of the upper monochromatic light is lambda9Wavelength of the lower monochromatic light is λ10(ii) a Then the incident angle of each monochromatic light can be obtained
Figure 128261DEST_PATH_IMAGE056
And has the following components:
Figure 28346DEST_PATH_IMAGE057
，
according to refractive index
Figure 144069DEST_PATH_IMAGE058
And combining the formulas
Figure 577325DEST_PATH_IMAGE059
The refractive index curve of the measured spherical element medium 13 is calculated.
Further, X is not less than 3.51≤4, 4.5≤X2≤5, 5.5≤X3≤6, 0.1≤X4≤0.5。
Fig. 13 shows a flowchart of this embodiment, and the method for measuring the refractive index of the spherical element medium provided in this embodiment corresponds to the function implemented in embodiment 1, so for other functions of this embodiment, reference may be made to the contents in embodiment one, and details are not repeated here.
The number of apparatuses and the scale of the process described herein are intended to simplify the description of the present invention. Applications, modifications and variations of the present invention will be apparent to those skilled in the art.
The features of the different implementations described herein may be combined to form other embodiments not specifically set forth above. The components may be omitted from the structures described herein without adversely affecting their operation. Further, various individual components may be combined into one or more individual components to perform the functions described herein.
Furthermore, while embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in a variety of fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.

Claims (2)

1. The device for measuring the refractive index of the spherical element medium comprises a spectrum confocal sensor (11), a spectrometer (14) and a distance adjusting mechanism, wherein the spectrum confocal sensor (11) comprises a white light point light source (S), a semi-transparent semi-reflecting mirror (X) and a dispersion objective lens (L); the semi-transparent and semi-reflective mirror (X) and the dispersion objective lens (L) are sequentially arranged between the white light point light source (S) and the spherical element medium (13) to be measured along the optical axis, the semi-transparent and semi-reflective mirror (X) is close to the white light point light source (S), and the dispersion objective lens (L) is close to the spherical element medium (13) to be measured; the distance adjustment mechanism drives the spectrum confocal sensor (11) and the measured spherical element medium (13) to be close to or far away from each other so that the distance between the dispersion objective lens (L) and the measured spherical element medium (13) changes 4 times along the optical axis; the spectrometer (14) is opposite to the reflecting surface of the semi-transparent semi-reflecting mirror (X) and is used for detecting the wavelength of the monochromatic light which is focused and reflected on the detected spherical element medium (13); if the upper surface and the lower surface of the measured spherical element medium (13) are both spherical surfaces, 5 different detected wavelengths are substituted into the formula:
Figure 10278DEST_PATH_IMAGE001
calculating the refractive index of the measured spherical element medium (13) at 5 wavelengths; if the surface of the spherical element medium (13) to be detected, which is opposite to the dispersive objective lens (L), is a plane, the detected 5 different wavelengths are substituted into the formula:
Figure 30318DEST_PATH_IMAGE002
calculating the refractive index of the measured spherical element medium (13) at 5 wavelengths; defining:
the central thickness of the spherical element medium is H;
the plurality of monochromatic lights decomposed by the dispersion objective lens (L) are composed of at least one monochromatic light subset, and each monochromatic light subset comprises an upper monochromatic light and a lower monochromatic light; the upper monochromatic light in each monochromatic photon concentration is focused on the upper surface of the measured spherical element medium (13), and the lower monochromatic light in each monochromatic photon concentration is focused on the lower surface of the measured spherical element medium (13);
the wavelength of the lower monochromatic light in each monochromatic photon set is lambda;
the incident angle of the lower monochromatic light of each monochromatic photon concentration is
Figure 284713DEST_PATH_IMAGE003
；
The focal distance between the upper monochromatic light and the lower monochromatic light in each monochromatic photon concentration is
Figure 163939DEST_PATH_IMAGE004
；
Wherein,
Figure 201296DEST_PATH_IMAGE005
and
Figure 75842DEST_PATH_IMAGE006
is a known parameter of a dispersive objective lens (L) in a spectral confocal sensor (11);
Figure 173242DEST_PATH_IMAGE007
is the curvature radius of the opposite side surface of the measured spherical element medium (13) and the dispersion objective lens (L);
the relationship between the marginal ray exit angle of the dispersive objective lens (L) and the wavelength is as follows:
Figure 8605DEST_PATH_IMAGE008
，
the rear intercept versus wavelength of a dispersive objective lens (L) is:
Figure 849653DEST_PATH_IMAGE009
，
the distance between the upper monochromatic light and the lower monochromatic light in each monochromatic light subset is as follows:
Figure 504671DEST_PATH_IMAGE010
；
defining:
when the distance between the dispersion objective lens (L) and the measured spherical element medium (13) is not changed, the wavelength of the upper monochromatic light is lambda1Wavelength of the lower monochromatic light is λ2；
When the distance between the dispersion objective lens (L) and the measured spherical element medium (13) is changed for the first time, the wavelength of the upper monochromatic light is lambda3Wavelength of the lower monochromatic light is λ4；
When the distance between the dispersion objective lens (L) and the measured spherical element medium (13) changes for the second time, the wavelength of the upper monochromatic light is lambda5Wavelength of the lower monochromatic light is λ6；
When the distance between the dispersion objective lens (L) and the measured spherical element medium (13) is changed for the third time, the wavelength of the upper monochromatic light is lambda7Wavelength of the lower monochromatic light is λ8；
When the distance between the dispersion objective lens (L) and the measured spherical element medium (13) is changed for the third time, the wavelength of the upper monochromatic light is lambda9Wavelength of the lower monochromatic light is λ10(ii) a Then the incident angle of each monochromatic light can be obtained
Figure 569710DEST_PATH_IMAGE011
And has the following components:
Figure 610478DEST_PATH_IMAGE012
，
according to refractive index
Figure 396163DEST_PATH_IMAGE013
And combining the formulas
Figure 182984DEST_PATH_IMAGE014
Calculating a refractive index curve of the detected spherical element medium (13);
wherein, X1、X2、X3、X4Is a wavelength term coefficient and has X of 3.5 ≤1≤4, 4.5≤X2≤5, 5.5≤X3≤6, 0.1≤X4Less than or equal to 0.5; A. b, C, D, E is the constant to be solved;
the wavelength range of the refractive index curve of the detected spherical element medium (13) is 400-1100 nm.
2. A method for measuring the refractive index of a spherical element medium is characterized by comprising the following steps:
providing a measuring device, wherein the measuring device comprises a spectrum confocal sensor (11), a spectrometer (14) and a distance adjusting mechanism, wherein the spectrum confocal sensor (11) comprises a white light point light source (S), a semi-transparent semi-reflecting mirror (X) and a dispersion objective lens (L); the semi-transparent and semi-reflective mirror (X) and the dispersion objective lens (L) are sequentially arranged between the white light point light source (S) and the spherical element medium (13) to be measured along the optical axis, the semi-transparent and semi-reflective mirror (X) is close to the white light point light source (S), and the dispersion objective lens (L) is close to the spherical element medium (13) to be measured;
the distance adjustment mechanism drives the spectrum confocal sensor (11) and the measured spherical element medium (13) to be close to or far away from each other so that the distance between the dispersion objective lens (L) and the measured spherical element medium (13) changes 4 times along the optical axis;
the spectrometer (14) is arranged opposite to the reflecting surface of the semi-transparent and semi-reflective mirror (X), and the spectrometer (14) is used for detecting the wavelength of monochromatic light which is focused and reflected on the detected spherical element medium (13);
if the upper surface and the lower surface of the measured spherical element medium (13) are both spherical surfaces, 5 different detected wavelengths are substituted into the formula:
Figure 887766DEST_PATH_IMAGE015
calculating the refractive index of the measured spherical element medium (13) at 5 wavelengths;
if the surface of the spherical element medium (13) to be detected, which is opposite to the dispersive objective lens (L), is a plane, the detected 5 different wavelengths are substituted into the formula:
Figure 822355DEST_PATH_IMAGE016
calculating the refractive index of the measured spherical element medium (13) at 5 wavelengths; defining:
the central thickness of the spherical element medium is H;
the plurality of monochromatic lights decomposed by the dispersion objective lens (L) are composed of at least one monochromatic light subset, and each monochromatic light subset comprises an upper monochromatic light and a lower monochromatic light; the upper monochromatic light in each monochromatic photon concentration is focused on the upper surface of the measured spherical element medium (13), and the lower monochromatic light in each monochromatic photon concentration is focused on the lower surface of the measured spherical element medium (13);
the wavelength of the lower monochromatic light in each monochromatic photon set is lambda;
the incident angle of the lower monochromatic light of each monochromatic photon concentration is
Figure 67523DEST_PATH_IMAGE017
；
The focal distance between the upper monochromatic light and the lower monochromatic light in each monochromatic photon concentration is
Figure 567905DEST_PATH_IMAGE018
；
Wherein,
Figure 505906DEST_PATH_IMAGE019
and
Figure 724528DEST_PATH_IMAGE020
is a known parameter of a dispersive objective lens (L) in a spectral confocal sensor (11);
Figure 773387DEST_PATH_IMAGE021
is a ball to be measuredA radius of curvature of an opposite side surface of the surface element medium (13) to the dispersive objective lens (L);
the relationship between the marginal ray exit angle of the dispersive objective lens (L) and the wavelength is as follows:
Figure 659434DEST_PATH_IMAGE022
，
the rear intercept versus wavelength of a dispersive objective lens (L) is:
Figure 592555DEST_PATH_IMAGE023
，
the distance between the upper monochromatic light and the lower monochromatic light in each monochromatic light subset is as follows:
Figure 111523DEST_PATH_IMAGE024
；
defining:
when the distance between the dispersion objective lens (L) and the measured spherical element medium (13) is not changed, the wavelength of the upper monochromatic light is lambda1Wavelength of the lower monochromatic light is λ2；
When the distance between the dispersion objective lens (L) and the measured spherical element medium (13) is changed for the first time, the wavelength of the upper monochromatic light is lambda3Wavelength of the lower monochromatic light is λ4；
When the distance between the dispersion objective lens (L) and the measured spherical element medium (13) changes for the second time, the wavelength of the upper monochromatic light is lambda5Wavelength of the lower monochromatic light is λ6；
When the distance between the dispersion objective lens (L) and the measured spherical element medium (13) is changed for the third time, the wavelength of the upper monochromatic light is lambda7Wavelength of the lower monochromatic light is λ8；
When the distance between the dispersion objective lens (L) and the measured spherical element medium (13) is changed for the third time, the wavelength of the upper monochromatic light is lambda9Wavelength of the lower monochromatic light is λ10(ii) a Then can obtainAngle of incidence of each of the lower monochromatic lights
Figure 698493DEST_PATH_IMAGE025
And has the following components:
Figure 970206DEST_PATH_IMAGE026
，
according to refractive index
Figure 250008DEST_PATH_IMAGE027
And combining the formulas
Figure 708803DEST_PATH_IMAGE028
Calculating a refractive index curve of the detected spherical element medium (13);
wherein, X1、X2、X3、X4Is a wavelength term coefficient and has X of 3.5 ≤1≤4, 4.5≤X2≤5, 5.5≤X3≤6, 0.1≤X4Less than or equal to 0.5; A. b, C, D, E is the constant to be solved;
the wavelength range of the refractive index curve of the detected spherical element medium (13) is 400-1100 nm.
CN202111072337.XA 2021-09-14 2021-09-14 Device and method for measuring refractive index of spherical element medium Active CN113514426B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202111072337.XA CN113514426B (en) 2021-09-14 2021-09-14 Device and method for measuring refractive index of spherical element medium

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202111072337.XA CN113514426B (en) 2021-09-14 2021-09-14 Device and method for measuring refractive index of spherical element medium

Publications (2)

Publication Number Publication Date
CN113514426A CN113514426A (en) 2021-10-19
CN113514426B true CN113514426B (en) 2021-12-14

Family

ID=78063217

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202111072337.XA Active CN113514426B (en) 2021-09-14 2021-09-14 Device and method for measuring refractive index of spherical element medium

Country Status (1)

Country Link
CN (1) CN113514426B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117826371B (en) * 2024-01-05 2024-07-16 浙江大学宁波“五位一体”校区教育发展中心 Compact spectral confocal measuring lens with long working distance and spectral confocal sensor

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7800746B2 (en) * 2006-08-11 2010-09-21 Northwestern University Method for identifying refractive-index fluctuations of a target
CN101769821A (en) * 2010-02-04 2010-07-07 北京理工大学 Lens refractive index and thickness measuring method and device based on differential confocal technology
CN102147240B (en) * 2010-12-24 2012-08-22 北京理工大学 Method and device for measuring multiple element parameters in differential con-focus interference manner
JP6196825B2 (en) * 2013-07-09 2017-09-13 オリンパス株式会社 Microscope system and method for measuring refractive index of sample
CN113375572B (en) * 2021-06-09 2022-12-06 西安邮电大学 Method and system for measuring thickness of GRIN lens by spectrum confocal method

Also Published As

Publication number Publication date
CN113514426A (en) 2021-10-19

Similar Documents

Publication Publication Date Title
Miks et al. Analysis of method for measuring thickness of plane-parallel plates and lenses using chromatic confocal sensor
CN107110739B (en) The optical evaluation of lens and lens die
US10551311B2 (en) Determining an absorption or turbidity coefficient of a liquid
JP5424143B2 (en) Reflection distribution curve modeling method, thickness measurement method using the same, and thickness measurement reflectometer
JP6000577B2 (en) Aspherical surface measuring method, aspherical surface measuring device, optical element processing apparatus, and optical element manufacturing method
JP5896792B2 (en) Aspherical surface measuring method, aspherical surface measuring device, and optical element processing device
US20140347660A1 (en) Metrological apparatus
CN113514426B (en) Device and method for measuring refractive index of spherical element medium
CN115597711B (en) Spectrometer and light path design method thereof
CN113175884A (en) Calibration device and calibration method of spectrum confocal measurement system
CN114440772B (en) Blazed transmission grating type spectrometer
CN101603921B (en) Detection system for refractive index dispersion properties and detection method thereof
EP1896792B1 (en) Method and system for measuring the curvature of an optical surface
EP0454090A1 (en) Objective lens system for use within microscope
CN113514424B (en) Measuring device and measuring method for plane uniform-thickness medium refractive index
Yoon et al. Microfluidic refractometer with micro-image defocusing
CN101701912A (en) Method for nondestructive measurement of refractive index of transparent capillary wall and device thereof
CN210863101U (en) Lens refractive index measuring device
CN113514425B (en) Calibration device and calibration method for refractive index of planar medium with equal thickness
CN110307963B (en) Method for detecting any wavelength focal length of transmission type optical system
CN109001141B (en) Infrared optical material impurity testing method
CN106442364B (en) Concentration sensor based on F-P cavity formed by coating film on end face of optical fiber
Antón et al. 3D-form metrology of arbitrary optical surfaces by absorption in fluids
CN117928396B (en) Method and device for measuring thickness and refractive index of transparent material
US20240053197A1 (en) Image pickup apparatus, measuring apparatus, and article manufacturing method

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant