CN108317962B - Method for measuring thickness and refractive index of common-path self-calibration film for eliminating transmitted light - Google Patents
Method for measuring thickness and refractive index of common-path self-calibration film for eliminating transmitted light Download PDFInfo
- Publication number
- CN108317962B CN108317962B CN201810084488.9A CN201810084488A CN108317962B CN 108317962 B CN108317962 B CN 108317962B CN 201810084488 A CN201810084488 A CN 201810084488A CN 108317962 B CN108317962 B CN 108317962B
- Authority
- CN
- China
- Prior art keywords
- measuring probe
- optical path
- signal
- measured
- light
- 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
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
-
- 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
- G01N21/4133—Refractometers, e.g. differential
Landscapes
- Physics & Mathematics (AREA)
- General 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)
- Immunology (AREA)
- Pathology (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
The invention discloses a method for measuring the thickness and the refractive index of a common-path self-calibration film for eliminating transmitted light, which belongs to the field of optical measurement and comprises the following steps: when the film to be detected is not inserted, the 1 st optical switch is turned on, the 2 nd optical switch is turned off, the optical path scanning device is driven to carry out optical path scanning, and the acquired signals are stored; closing the 1 st optical switch, opening the 2 nd optical switch, driving the optical path scanning device to perform optical path scanning, and storing the acquired signals; demodulating the acquired signal; if the thickness of the opaque film to be measured is measured, opening a 1 st optical switch and a 2 nd optical switch, driving an optical path scanning device to perform optical path scanning, performing optical path matching, and storing the collected signals; demodulating the collected signal to obtain a double optical path; calculating the thickness of the opaque film to be detected; the method is similar when measuring the thickness and refractive index of the transparent film. The invention has multiple measuring functions; the influence of transmitted light can be eliminated, and the precision is improved; the identification difficulty is reduced; the complexity of the optical path is reduced, and the measuring speed is improved.
Description
Technical Field
The invention belongs to the field of optical measurement, and particularly relates to a method for measuring the thickness and the refractive index of a common-path self-calibration film for eliminating transmitted light.
Background
With the vigorous development of material science and technology, in order to meet the urgent needs in the fields of microelectronics, optoelectronics, new energy and the like, films are widely applied in the fields of optical engineering, mechanical engineering, communication engineering, bioengineering, aerospace engineering, chemical engineering, medical engineering and the like. The thickness of the film is not only a key parameter in the production of the film, but also determines the application performance of the film in the fields of mechanics, electromagnetism, photoelectricity, optics and the like. Accurate measurement of film thickness has been one of the important links in film production and application.
In 1941, n.schwartz et al proposed a contact probe method for sensing changes in surface profile by using the motion of a high-precision mechanical stylus on the surface of an object, which has the advantages of good stability, high resolution, large measurement range, etc.; however, the probe method includes a probe based on mechanical movement, and thus, a secondary process is required for measuring the thin film, and the thin film is damaged to some extent by the movement of the probe on the surface of the thin film. Thus, non-contact measurements quickly replaced contact measurements.
2013, a Chinese patent application number 201310198294.9, discloses an ultrasonic film thickness measuring instrument and a measuring method thereof, wherein the method transmits ultrasonic pulses to be incident to the surface of an oil film to generate resonance, and then measures the thickness of the oil film by measuring the relevant characteristics of the reflected pulses; however, the method is only suitable for the measurement of the liquid mode, different models need to be established for films with different thickness ranges, and the demodulation difficulty is high.
Optical measurement has the advantage of high accuracy and is beginning to be widely used in the field of film thickness measurement. In 2012, the patent application No. 201210080754.2 discloses a film thickness measuring device and method by the company of Qujie et al, Beijing east photoelectric technology, Inc., which adopts a combination of a space optical path and an optical fiber optical path, and uses a prism to perform light splitting treatment on a color light source to irradiate the surface of a film, and measures the thickness of the film by measuring the characteristics of different reflected lights. The method expands the frequency spectrum range of the sampling point of the device for measuring the film thickness and improves the resolution ratio.
As a part of optical measurement methods, white light interferometry has been developed in the field of film thickness measurement because of its absolute measurement advantage. The basic principle of the white light interferometry is as follows: the method comprises the steps that a scanning mirror is connected to the tail end of one arm of a white light interferometer and serves as a sensing arm, the length of the other arm is fixed and serves as a reference arm, the length of the sensing arm is changed by moving the scanning mirror, when the optical path of light transmitted in the sensing arm is matched with the optical path of light transmitted in the reference arm, the interference peak value is maximum, and the measurement of relevant parameters is achieved by identifying the position of the peak value. In 2008, peterj. degroot et al, Zygo, usa, discloses a scanning interferometry for film thickness and surface measurement, which employs a film thickness measurement method based on the white light interference principle, and extracts two peak values from an interference light intensity map by using a fourier transform method, which is not affected by film thickness, and is suitable for measuring films with a thickness greater than the coherence length of a light source, and also suitable for measuring films with a thickness less than the coherence length of a light source. In 2014, jia legend wu et al of Shandong university disclose a system for measuring film thickness by a wide-spectrum optical interference method, with patent application number 201410290494.1, the system forms a Fabry-Perot interferometer between a reflector and a collimator, and the thickness of a film to be measured can be obtained by measuring the length of a Fabry-Perot cavity before and after the film to be measured is placed under the reflector.
In 2017, patent with application number CN201710277954.0 discloses a common-path self-calibration film thickness measuring device and a measuring method, the method utilizes a common-path wide-spectrum optical interferometer and a laser interferometer to realize the measurement of the film thickness, and has the advantages of common path, no need of calibrating devices and the like, but the method cannot eliminate the influence of laser transmission light, so that the cracking of laser interference signals is caused, and the thickness measuring precision is influenced; 2017, patent with application number CN201710277939.6 discloses a polarization multiplexing common-path self-calibration film thickness measurement device and a measurement method, which can further eliminate the influence of transmitted light on the measurement result, but the device is more complicated to set up.
Disclosure of Invention
The invention aims to disclose a method for measuring the thickness and the refractive index of a common-path self-calibration film with high tracing precision and strong anti-interference capability and capable of eliminating transmitted light.
The purpose of the invention is realized as follows:
the method for measuring the thickness and the refractive index of the common-path self-calibration film for eliminating the transmitted light comprises the following steps:
step (1): when the film to be detected is not inserted, the 1 st optical switch 405 is opened, the 2 nd optical switch 406 is closed, the optical path scanning device 603 is driven to perform optical path scanning, so that optical path matching is performed between the internal reflected light 411 of the 1 st measuring probe and the reflected light 412 of the emergent light of the 1 st measuring probe on the outer surface of the 2 nd measuring probe, and a signal m30 acquired by the 3 rd photoelectric detector and a signal m40 acquired by the 4 th photoelectric detector are stored; the 1 st optical switch 405 has the same optical parameters as the 2 nd optical switch 406;
step (2): closing the 1 st optical switch 405, opening the 2 nd optical switch 406, and driving the optical path scanning device 603 to perform optical path scanning, so that the 2 nd measuring probe internal reflected light 421 and the 2 nd measuring probe emergent light perform optical path matching on the 1 st measuring probe external surface reflected light 422; saving the signal m10 collected by the 1 st photodetector 703 and the signal m20 collected by the 2 nd photodetector 704;
and (3): demodulating a signal m10 acquired by the 1 st photoelectric detector, a signal m20 acquired by the 2 nd photoelectric detector, a signal m30 acquired by the 3 rd photoelectric detector and a signal m40 acquired by the 4 th photoelectric detector to obtain a double optical path H between the 1 st measuring probe and the 2 nd measuring probe;
and (4): if the thickness of the opaque film 403 to be measured is measured, the 1 st optical switch 405 and the 2 nd optical switch 406 are opened, and the opaque film 403 to be measured is inserted between the 1 st measuring probe 401 and the 2 nd measuring probe 402, so that the opaque film 403 to be measured is perpendicular to the emergent light rays of the 1 st measuring probe 401 and the 2 nd measuring probe 402 at the same time; driving the optical path scanning device 603 to perform optical path scanning, so that optical path matching is performed on the 1 st measuring probe internal reflected light 413 and the 1 st measuring probe emergent light on the front surface reflected light 414 of the opaque film to be measured, and optical path matching is performed on the 2 nd measuring probe internal reflected light 423 and the 2 nd measuring probe emergent light on the rear surface reflected light 424 of the opaque film to be measured; storing a signal m11 collected by the 1 st photoelectric detector, a signal m21 collected by the 2 nd photoelectric detector, a signal m31 collected by the 3 rd photoelectric detector and a signal m41 collected by the 4 th photoelectric detector; the 1 st measurement probe 401 and the 2 nd measurement probe 402 have the same optical parameters;
and (5): demodulating a signal m11 acquired by the 1 st photoelectric detector, a signal m21 acquired by the 2 nd photoelectric detector, a signal m31 acquired by the 3 rd photoelectric detector and a signal m41 acquired by the 4 th photoelectric detector to respectively obtain a double optical path H1 between the 1 st measuring probe and the front surface of the film to be measured and a double optical path H2 between the 2 nd measuring probe and the front surface of the film to be measured;
and (6): calculating the thickness d1 of the opaque film to be measured:
and (7): if the thickness of the transparent film is measured, the 1 st optical switch 405 is turned on, the 2 nd optical switch 406 is turned off, and the transparent film to be measured 404 is inserted between the 1 st measuring probe 401 and the 2 nd measuring probe 402, so that the transparent film to be measured 404 is perpendicular to the emergent light rays of the 1 st measuring probe 401 and the 2 nd measuring probe 402; driving the optical path scanning device 603 to perform optical path scanning, so that optical path matching is performed on the 1 st measuring probe internal reflection light 415, the 1 st measuring probe emergent light reflected light 416 on the front surface of the transparent film to be measured, and the 1 st measuring probe emergent light reflected light 417 on the rear surface of the transparent film to be measured respectively, and a signal m32 collected by the 3 rd photoelectric detector and a signal m42 collected by the 4 th photoelectric detector are stored;
and (8): closing the 1 st optical switch 405, opening the 2 nd optical switch 406, driving the optical path scanning device 603 to perform optical path scanning, so that optical path matching is performed on the 2 nd measuring probe internal reflection light 425, the 2 nd measuring probe emergent light reflected light 426 on the rear surface of the transparent film to be measured and the 2 nd measuring probe emergent light reflected light 427 on the front surface of the transparent film to be measured respectively, and storing a signal m12 collected by the 1 st photoelectric detector and a signal m22 collected by the 2 nd photoelectric detector 704;
and (9): demodulating a signal m12 acquired by the 1 st photoelectric detector, a signal m22 acquired by the 2 nd photoelectric detector, a signal m32 acquired by the 3 rd photoelectric detector and a signal m42 acquired by the 4 th photoelectric detector to obtain a double optical path H3 between the 1 st measuring probe and the front surface of the transparent film to be measured and a double optical path H4 between the 1 st measuring probe and the rear surface of the transparent film to be measured, and obtaining a double optical path H5 between the 2 nd measuring probe and the rear surface of the transparent film to be measured and a double optical path H6 between the 2 nd measuring probe and the front surface of the transparent film to be measured;
step (10): calculating the thickness d2 of the transparent film 404 to be measured:
when the refractive index of air is 1, the refractive index n of the transparent film to be measured 404 is:
the invention has the beneficial effects that:
the double probes adopted by the invention can simultaneously measure the thickness of the transparent and non-transparent films and the refractive index of the transparent film in a non-contact manner; the invention controls the two measuring probes to work in a time-sharing way, eliminates the influence of laser transmission light on the quality of interference signals when the two probes are coupled, and improves the accuracy of measurement traceability; the interference of broad spectrum light transmission light on the identification of the characteristic signal peak when the two probes are coupled is eliminated, and the identification difficulty of the measured characteristic signal is reduced; the two measuring probes share the same demodulation interferometer, so that the characteristic signals of the two measuring probes directly appear in the same scanning range of the optical path scanning device, the complexity of an optical path is reduced, and the measuring speed is improved; the design of the double light sources sharing the light path and the differential light path structure can further reduce the influence of the external environment disturbance on the film thickness measurement result.
Drawings
FIG. 1 is a flow chart of a method for measuring the thickness of a transparent film and an opaque film and the refractive index of the transparent film;
FIG. 2 is a diagram of an optical path inside a measurement probe module when a 1 st optical switch is opened and a 2 nd optical switch is closed without loading a film to be measured;
FIG. 3 is a diagram of the optical path inside the measurement probe module when the 1 st optical switch is closed and the 2 nd optical switch is opened without loading the film to be measured;
FIG. 4 is a diagram of the internal optical path of the measurement probe module when loading the opaque film to be measured;
FIG. 5 is a diagram of an optical path inside the measurement probe module when the 1 st optical switch for loading the transparent film to be measured is turned on and the 2 nd optical switch is turned off;
FIG. 6 is a diagram of the optical path inside the measurement probe module when the 1 st optical switch of the transparent film to be measured is loaded and the 2 nd optical switch is turned on;
FIG. 7 is a schematic diagram illustrating the tracing principle of laser interference signals;
FIG. 8 is a schematic diagram of a distance measurement method based on the principle of white light interference when a film to be measured is not loaded;
FIG. 9 is a schematic diagram of an apparatus for a method of common-path self-aligned film thickness and refractive index measurement with elimination of transmitted light.
Detailed Description
The invention is further described below with reference to the accompanying drawings:
referring to fig. 1, the method for measuring the thickness and refractive index of the common-path self-calibration film by eliminating the transmitted light comprises the following steps:
step (1): when the film to be detected is not inserted, the 1 st optical switch 405 is opened, the 2 nd optical switch 406 is closed, the optical path scanning device 603 is driven to perform optical path scanning, so that optical path matching is performed between the internal reflected light 411 of the 1 st measuring probe and the reflected light 412 of the emergent light of the 1 st measuring probe on the outer surface of the 2 nd measuring probe, and a signal m30 acquired by the 3 rd photoelectric detector and a signal m40 acquired by the 4 th photoelectric detector are stored; the 1 st optical switch 405 has the same optical parameters as the 2 nd optical switch 406;
step (2): closing the 1 st optical switch 405, opening the 2 nd optical switch 406, and driving the optical path scanning device 603 to perform optical path scanning, so that the 2 nd measuring probe internal reflected light 421 and the 2 nd measuring probe emergent light perform optical path matching on the 1 st measuring probe external surface reflected light 422; saving the signal m10 collected by the 1 st photodetector 703 and the signal m20 collected by the 2 nd photodetector 704;
and (3): demodulating a signal m10 acquired by the 1 st photoelectric detector, a signal m20 acquired by the 2 nd photoelectric detector, a signal m30 acquired by the 3 rd photoelectric detector and a signal m40 acquired by the 4 th photoelectric detector to obtain a double optical path H between the 1 st measuring probe and the 2 nd measuring probe;
and (4): if the thickness of the opaque film 403 to be measured is measured, the 1 st optical switch 405 and the 2 nd optical switch 406 are opened, and the opaque film 403 to be measured is inserted between the 1 st measuring probe 401 and the 2 nd measuring probe 402, so that the opaque film 403 to be measured is perpendicular to the emergent light rays of the 1 st measuring probe 401 and the 2 nd measuring probe 402 at the same time; driving the optical path scanning device 603 to perform optical path scanning, so that optical path matching is performed on the 1 st measuring probe internal reflected light 413 and the 1 st measuring probe emergent light on the front surface reflected light 414 of the opaque film to be measured, and optical path matching is performed on the 2 nd measuring probe internal reflected light 423 and the 2 nd measuring probe emergent light on the rear surface reflected light 424 of the opaque film to be measured; storing a signal m11 collected by the 1 st photoelectric detector, a signal m21 collected by the 2 nd photoelectric detector, a signal m31 collected by the 3 rd photoelectric detector and a signal m41 collected by the 4 th photoelectric detector; the 1 st measurement probe 401 and the 2 nd measurement probe 402 have the same optical parameters;
and (5): demodulating a signal m11 acquired by the 1 st photoelectric detector, a signal m21 acquired by the 2 nd photoelectric detector, a signal m31 acquired by the 3 rd photoelectric detector and a signal m41 acquired by the 4 th photoelectric detector to respectively obtain a double optical path H1 between the 1 st measuring probe and the front surface of the film to be measured and a double optical path H2 between the 2 nd measuring probe and the front surface of the film to be measured;
and (6): calculating the thickness d1 of the opaque film to be measured:
and (7): if the thickness of the transparent film is measured, the 1 st optical switch 405 is turned on, the 2 nd optical switch 406 is turned off, and the transparent film to be measured 404 is inserted between the 1 st measuring probe 401 and the 2 nd measuring probe 402, so that the transparent film to be measured 404 is perpendicular to the emergent light rays of the 1 st measuring probe 401 and the 2 nd measuring probe 402; driving the optical path scanning device 603 to perform optical path scanning, so that optical path matching is performed on the 1 st measuring probe internal reflection light 415, the 1 st measuring probe emergent light reflected light 416 on the front surface of the transparent film to be measured, and the 1 st measuring probe emergent light reflected light 417 on the rear surface of the transparent film to be measured respectively, and a signal m32 collected by the 3 rd photoelectric detector and a signal m42 collected by the 4 th photoelectric detector are stored;
and (8): closing the 1 st optical switch 405, opening the 2 nd optical switch 406, driving the optical path scanning device 603 to perform optical path scanning, so that optical path matching is performed on the 2 nd measuring probe internal reflection light 425, the 2 nd measuring probe emergent light reflected light 426 on the rear surface of the transparent film to be measured and the 2 nd measuring probe emergent light reflected light 427 on the front surface of the transparent film to be measured respectively, and storing a signal m12 collected by the 1 st photoelectric detector and a signal m22 collected by the 2 nd photoelectric detector 704;
and (9): demodulating a signal m12 acquired by the 1 st photoelectric detector, a signal m22 acquired by the 2 nd photoelectric detector, a signal m32 acquired by the 3 rd photoelectric detector and a signal m42 acquired by the 4 th photoelectric detector to obtain a double optical path H3 between the 1 st measuring probe and the front surface of the transparent film to be measured and a double optical path H4 between the 1 st measuring probe and the rear surface of the transparent film to be measured, and obtaining a double optical path H5 between the 2 nd measuring probe and the rear surface of the transparent film to be measured and a double optical path H6 between the 2 nd measuring probe and the front surface of the transparent film to be measured;
step (10): calculating the thickness d2 of the transparent film 404 to be measured:
when the refractive index of air is 1, the refractive index n of the transparent film to be measured 404 is:
example 1 is given below:
the used device is shown in fig. 9, and the light source output module 1 is composed of a broad spectrum light source 101 with a central wavelength of 1310nm, a narrow band frequency stabilization laser light source 103 with a wavelength of 1550nm, a 1 st isolator 102 with an operating wavelength of 1310nm, a 2 nd isolator 104 with an operating wavelength of 1550nm, and a 1 st wavelength division multiplexer 105 with operating wavelengths of 1310nm and 1550 nm. Wherein, the output light of the broad spectrum light source 101 with the central wavelength of 1310nm is used as a measuring beam and is mainly used for realizing the absolute measurement of the film thickness; the output light of the narrow-band frequency-stabilized laser light source 103 with the wavelength of 1550nm is used as a light path correction light beam and is mainly used for tracing the film thickness measurement. The film thickness measuring probe module 4 is characterized in that: the film thickness measuring probe module 4 consists of a 1 st measuring probe 401, a 2 nd measuring probe 402, a 1 st optical switch 405 and a 2 nd optical switch 406; the 1 st measurement probe 401 and the 2 nd measurement probe 402 have the same optical parameters; the 1 st optical switch 405 has the same optical parameters as the 2 nd optical switch 406; the 1 st measuring probe 401 and the 2 nd measuring probe 402 can simultaneously realize transmission and reflection of transmitted light, and the reflectivity of the transmitted light is between 20% and 80%; the 1 st optical switch 405 and the 2 nd optical switch 406 realize the on-off function of the optical path; the emergent rays of the 1 st measuring probe 401 and the 2 nd measuring probe 402 are overlapped with each other; when the device to be measured is placed and measured, the device to be measured is perpendicular to the emergent rays of the 1 st measuring probe 401 and the 2 nd measuring probe 402 respectively; the demodulation interferometer module 6 is characterized in that: the demodulation interferometer module 6 is composed of a 1 st demodulation interferometer coupler 601, a 2 nd demodulation interferometer coupler 602 and an optical path scanning device 603; wherein the 1 st demodulation interferometer coupler 601 has the same optical parameters as the 2 nd demodulation interferometer coupler 602; the scanning range L of the optical path scanning device 603 can satisfy the requirement of realizing optical path matching between the reflected lights by different probes during the self-calibration of the system.
The optical interferometry is the distance measurement method with the highest precision at present, but the laser interferometry cannot realize the measurement of absolute quantity due to the longer coherence length of the laser light source. White light interferometry uses a broad spectrum light source with low coherence. Because the coherence length of the low coherence light source is very small, the shape of the interference fringe output after interference is a sinusoidal oscillation modulated by a gaussian envelope, and the fringe has a main maximum value corresponding to the position where the optical path difference between the two arms of the interferometer is zero. Because of the harsh requirement on the optical path difference of two arms of the interferometer, the position of the central fringe provides a good-quality reference position for the measurement of the physical quantity, and the absolute value of the change of the measured physical quantity can be obtained according to the change of the position of the central fringe. Thus, the measurement of the physical quantity in the white light interferometry system is converted into a measurement of the change in the position of the central fringe of the interference signal. The invention adopts the design of double light sources, as shown in fig. 7, in the scanning process of the optical path scanning device, white light interference signals and laser interference signals are recorded simultaneously, and the actual moving distance of the optical path scanning device can be calibrated with high precision by reading the number of the laser interference signal fringes. The light emitted by the two light sources respectively passes through the 1 st isolator 102 and the 2 nd isolator 104 and enters the 1 st wavelength division multiplexer 105 to be combined into one beam, and the beam is jointly entered into the beam splitting coupler 2 with the splitting ratio of 3dB, and is equally divided into two paths: one path enters the 1 st measuring probe 401 through the 1 st measuring interferometer coupler 3 and the 1 st optical switch 405 with the splitting ratio of 3dB, and the other path enters the 2 nd measuring probe module 402 through the 2 nd measuring interferometer coupler 5 and the 2 nd optical switch 406 with the splitting ratio of 3 dB; the ratio of the reflectivity of the lens end face to the transmissivity of the 1 st measuring probe 401 and the 2 nd measuring probe 402 is 50: 50; when the optical switch is connected, the insertion loss of the optical switch is less than 0.3dB, and when the optical switch is disconnected, the insertion loss of the optical switch is more than 60 dB; the measuring light returned from the 1 st measuring probe 401 is transmitted to the demodulation interferometer module 6 through the 1 st optical switch 405 and the 1 st measuring interferometer coupler 3 with the splitting ratio of 3 dB; the measurement light returned from the 2 nd measurement probe 402 is transmitted to the demodulation interferometer module 6 through the 2 nd optical switch 406 and the 2 nd measurement interferometer coupler 5 with the splitting ratio of 3 dB; the optical path scanning by the optical path scanning device 603 performs interference at the 1 st demodulation interferometer coupler 601 having a splitting ratio of 3dB and the 2 nd demodulation interferometer coupler 602 having a splitting ratio of 3dB, respectively. The 2 nd wavelength division multiplexer 707 and the 3 rd wavelength division multiplexer 708 respectively separate a broad spectrum light measurement beam with a center wavelength of 1310nm and a laser correction beam with a wavelength of 1550nm, and then the separated light beams are acquired by the 1 st photodetector 703, the 2 nd photodetector 704, the 3 rd photodetector 705 and the 4 th photodetector 706. The photodetector transmits the collected signal to the computer 701 through the data acquisition card 702 for demodulation, and the computer 701 is also responsible for driving the optical path scanning device 603. For example, in the distance measuring method used in the present invention, as shown in fig. 8, the reflected light 411 inside the 1 st measuring probe 401 and the reflected light 412 of the 1 st measuring probe 401 on the outer surface of the 2 nd measuring probe 402 are divided into two paths by the 1 st demodulation interferometer coupler: one path goes directly into the 2 nd demodulation interferometer coupler 602, producing 411 'and 412' reflected light; one path goes directly into the optical path scanning device 603, generating the 411 "and 412" reflected light. Under the control of the computer 701, the optical path scanning device 603 performs optical path scanning, and as shown in fig. 8, the process of generating the wide-spectrum optical interference signal is as follows: (1) when the optical path difference between the two arms is equal to 2H, the light 411' in the scanning arm matches the light 412 "in the fixed arm, and a 1 st maximum white light interference signal 431 is generated. (2) When the optical path difference between the two arms is equal to 0, the light 411 'and 411 ″ and the light 412' and 412 ″ in the scanning arm and the fixed arm are matched, and a dominant white light interference signal 432 is generated. (3) When the optical path difference between the two arms is equal to-2H, the light 412 'in the scanning arm is matched with the light 411' in the fixed arm, and then a 2 nd maximum white light interference signal 433 is generated. (4) By extracting the position of the central fringe of the white light interference signal, the absolute difference of the scanning distance between the major maximum and the minor maximum is obtained by utilizing the tracing characteristic of the laser interference signal, and the absolute difference represents the absolute double optical path between the 1 st measuring probe 401 and the 2 nd measuring probe 402.
When the film to be measured is not inserted, the 1 st optical switch 405 is turned on, the 2 nd optical switch 406 is turned off, and the output light is split by the splitting coupler 2 with the splitting ratio of 3 dB: one beam enters the 1 st measuring probe 401 through the 1 st measuring interferometer coupler 3 with the splitting ratio of 3dB and the 1 st optical switch 405, and the other beam can not carry out relevant parameter measurement because the 2 nd optical switch 406 is closed. As shown in FIG. 2, the reflected light beam 411 from the inner surface of the lens of the 1 st measurement probe 401 itself, the reflected light beam 412 from the outer surface of the lens of the 2 nd measurement probe 402 are transmitted to the demodulation interferometer module 6 through the 1 st optical switch 405 and the 1 st measurement interferometer coupler 3 with a splitting ratio of 3dB, and the transmission mode of the light beams in the demodulation interferometer module 6 is as follows: inputting the return light of the film thickness measuring probe 401 into a 1 st demodulation interferometer coupler 601 with the splitting ratio of 3dB by a 1 st measurement interferometer coupler 3 with the splitting ratio of 3dB, transmitting the return light into a 2 nd demodulation interferometer coupler 602 through an optical fiber and an optical path scanning device 603, generating optical path complete matching between the reflected light 411 and the reflected light 412 when the optical path scanning device 603 moves, forming white light interference fringes on a 3 rd photoelectric detector 705, forming laser interference fringes on a 4 th photoelectric detector 706, and storing signals collected by the 3 rd photoelectric detector 705 and the 4 th photoelectric detector 706; turning off the 1 st optical switch 405 and turning on the 2 nd optical switch 406, the output light of the light source output module is split by the splitting coupler 2 with the splitting ratio of 3 dB: one beam enters the 2 nd measuring probe 402 through the 2 nd measuring interferometer coupler 5 with the splitting ratio of 3dB and the 2 nd optical switch 406, and the other beam can not carry out relevant parameter measurement because the 1 st optical switch 405 is closed, as shown in FIG. 3, the 2 nd measuring probe 402 self lens internal reflection beam 421, the 1 st measuring probe 401 lens external surface reflection beam 422 pass through the 2 nd optical switch 406 and the 2 nd measuring interferometer coupler 5 with the splitting ratio of 3dB and are transmitted to the demodulation interferometer module 6; the transmission mode in the beam demodulation interferometer module 6 is as follows: inputting the return light of the film thickness measuring probe 402 into a 2 nd demodulation interferometer coupler 607 with a splitting ratio of 3dB by a 2 nd measurement interferometer coupler 5 with a splitting ratio of 3dB, transmitting the return light into a 1 st demodulation interferometer coupler 601 through an optical fiber and an optical path scanning device 603, when the optical path scanning device 603 moves, enabling the optical paths of the reflected light 421 and the reflected light 422 to be completely matched, forming a white light interference fringe on a 1 st photodetector 703, forming a laser interference fringe on a 2 nd photodetector 704, and storing signals collected by the 1 st photodetector 703 and the 2 nd photodetector 704; and demodulating and recording the acquired signals to obtain a double optical path H between the two measuring probes.
When the opaque film 403 to be measured is inserted between the 1 st measurement probe 401 and the 2 nd measurement probe 402, the 1 st optical switch 405 and the 2 nd optical switch 406 are turned on, and the output light of the light source output module is split by the beam splitter coupler 2 with the splitting ratio of 3 dB: one beam enters the 1 st measuring probe 401 through the 1 st measuring interferometer coupler 3 and the 1 st optical switch 405 with the split ratio of 3dB, and the other beam enters the 2 nd measuring probe 402 through the 2 nd measuring interferometer coupler 5 and the 2 nd optical switch 406 with the split ratio of 3 dB. As shown in FIG. 4, the 1 st measuring probe 401, the lens inner surface reflected light beam 413, the opaque film to be measured front surface 403a reflected light beam 414 are inputted into the demodulation interferometer module 6 through the 1 st optical switch 405 and the 1 st measuring interferometer coupler 3 having a spectroscopic ratio of 3 dB; the 2 nd measuring probe 402 lens inner surface reflected light beam 423, the opaque film to be measured rear surface 403b reflected light beam 424 pass through the 2 nd optical switch 406 and the 2 nd measuring interferometer coupler 5 with a spectroscopic ratio of 3dB and are input into the demodulation interferometer module 6. The transmission mode of the return light of the 1 st probe 401 in the demodulation interferometer module 6 is as follows: inputting the return light of the film thickness measuring probe 401 into a 1 st demodulation interferometer coupler 601 with the splitting ratio of 3dB by a 1 st measurement interferometer coupler 3 with the splitting ratio of 3dB, transmitting the return light into a 2 nd demodulation interferometer coupler 602 through an optical fiber and an optical path scanning device 603, when the optical path scanning device 603 moves, generating optical path perfect matching between the reflected light 413 and the reflected light 414, forming a white light interference fringe on a 3 rd photoelectric detector 705, forming a laser interference fringe on a 4 th photoelectric detector 706, and storing signals collected by the 3 rd photoelectric detector 705 and the 4 th photoelectric detector 706; the transmission mode of the return light of the 1 st probe 401 in the demodulation interferometer module 6 is as follows: inputting the return light of the film thickness measuring probe 402 into a 2 nd demodulation interferometer coupler 607 with a splitting ratio of 3dB by a 2 nd measurement interferometer coupler 5 with a splitting ratio of 3dB, transmitting the return light into a 1 st demodulation interferometer coupler 603 through an optical fiber and an optical path scanning device 603, generating optical path matching between the reflected light 423 and the reflected light 424 when the optical path scanning device 603 moves, forming white light interference fringes on the 1 st photodetector 703, forming laser interference fringes on the 2 nd photodetector 704, and storing signals collected by the 1 st photodetector 703 and the 2 nd photodetector 704; the acquired signals are demodulated and recorded, so that a double optical path H1 of the front surface 403a of the film to be measured of the 1 st measuring probe 401 and a double optical path H2 of the front surface 403b of the film to be measured of the 2 nd measuring probe 402 are obtained. Thus, the thickness d1 of opaque film 403 to be measured is determined by the two measurements described above, namely:
when the transparent film 404 to be measured is inserted between the 1 st measuring probe 401 and the 2 nd measuring probe 402, the 1 st optical switch 405 is turned on, the 2 nd optical switch 406 is turned off, and the output light of the light source output module is split by the beam splitter coupler 2 with the splitting ratio of 3 dB: one beam enters the 1 st measuring probe 401 through the 1 st measuring interferometer coupler 3 with the splitting ratio of 3dB and the 1 st optical switch 405, and the other beam can not carry out relevant parameter measurement because the 2 nd optical switch 406 is closed; as shown in fig. 5, the light beam 415 reflected by the inner surface of the lens of the 1 st measuring probe 401 itself, the light beam 416 reflected by the front surface 404a of the transparent film to be measured, and the light beam 417 reflected by the rear surface 404b of the transparent film to be measured are transmitted to the demodulation interferometer module 6 through the 1 st optical switch 405 and the 1 st measuring interferometer coupler 3 with a splitting ratio of 3dB, and the transmission mode of the light beam in the demodulation interferometer module 6 is as follows: inputting the return light of the film thickness measuring probe 401 into a 1 st demodulation interferometer coupler 601 with a splitting ratio of 3dB by a 1 st measurement interferometer coupler 3 with a splitting ratio of 3dB, transmitting the light beam into a 2 nd demodulation interferometer coupler 602 through an optical fiber and an optical path scanning device 603, enabling the optical paths of reflected light 415, reflected light 416 and reflected light 417 to be completely matched when the optical path scanning device moves, forming a white light interference fringe on a 3 rd photodetector 705, forming a laser interference fringe on a 4 th photodetector 706, storing signals collected by the 3 rd photodetector 705 and the 4 th photodetector 706, demodulating and recording the collected signals, and obtaining a double optical path length H3 between the 1 st measuring probe 401 and a front surface 404a of the transparent film to be measured and a double optical path length H4 between the 1 st measuring probe 401 and a rear surface 404b of the transparent film to be measured; the 1 st optical switch 405 is turned off, the 2 nd optical switch 406 is turned on, and the output light of the light source output module is split by the splitting coupler 2 with the splitting ratio of 3 dB: one beam enters the 2 nd measuring probe 402 through the 2 nd measuring interferometer coupler 5 with the splitting ratio of 3dB and the 2 nd optical switch 406, and the other beam can not carry out relevant parameter measurement because the 1 st optical switch 405 is closed, as shown in FIG. 6, the 2 nd measuring probe 402 reflects a beam 425 from the inner surface of the lens, reflects a light 426 from the back surface 404b of the transparent film to be measured, and reflects a light 427 from the front surface 404a of the transparent film to be measured, and the light is transmitted to the demodulation interferometer module 6 through the 2 nd optical switch 406 and the 2 nd measuring interferometer coupler 5 with the splitting ratio of 3dB, and the transmission mode of the light beam in the demodulation interferometer module 6 is as follows: inputting the return light of the film thickness measuring probe 402 into a 2 nd demodulation interferometer coupler 602 with the splitting ratio of 3dB by a 2 nd measurement interferometer coupler 5 with the splitting ratio of 3dB, transmitting the light beam into a 1 st demodulation interferometer coupler 601 through an optical fiber and an optical path scanning device 603, when the optical path scanning device moves, completely matching the optical paths of reflected light 425, reflected light 426 and reflected light 427, forming a white light interference fringe on a 1 st photodetector 703, forming a laser interference fringe on a 2 nd photodetector 704, storing the signals collected by the 1 st photodetector 703 and the 2 nd photodetector 704, and obtaining a double optical path length H5 between the 2 nd measuring probe 402 and the rear surface 404b of the transparent film to be measured and a double optical path length H6 between the 2 nd measuring probe 402 and the front surface 404a of the transparent film to be measured;
the thickness d2 of the transparent film 404 to be measured can be determined by the above-mentioned two measurements, i.e.
When the refractive index of air is 1, the refractive index n of the transparent film 404 can be determined by the above two measurements, i.e.
Compared with the prior art, the double probes adopted by the invention can simultaneously measure the thickness of the transparent and non-transparent films and the refractive index of the transparent film in a non-contact manner; the invention controls the two measuring probes to work in a time-sharing way, eliminates the influence of laser transmission light on the quality of interference signals when the two probes are coupled, and improves the accuracy of measurement traceability; the interference of broad spectrum light transmission light on the identification of the characteristic signal peak when the two probes are coupled is eliminated, and the identification difficulty of the measured characteristic signal is reduced; the two measuring probes share the same demodulation interferometer, so that the characteristic signals of the two measuring probes directly appear in the same scanning range of the optical path scanning device, the complexity of an optical path is reduced, and the measuring speed is improved; the design of the double light sources sharing the light path and the differential light path structure can further reduce the influence of the external environment disturbance on the film thickness measurement result.
The above description is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (2)
1. The method for measuring the thickness and the refractive index of the common-path self-calibration film for eliminating the transmitted light is characterized by comprising the following steps of: comprises the following steps:
step (1): when a film to be detected is not inserted, a 1 st optical switch (405) is opened, a 2 nd optical switch (406) is closed, an optical path scanning device (603) is driven to carry out optical path scanning, so that optical path matching is carried out on reflected light (411) inside a 1 st measuring probe and reflected light (412) of emergent light of the 1 st measuring probe on the outer surface of the 2 nd measuring probe, and a signal m30 collected by a 3 rd photoelectric detector and a signal m40 collected by a 4 th photoelectric detector are stored;
step (2): closing the 1 st optical switch (405), opening the 2 nd optical switch (406), driving an optical path scanning device (603) to perform optical path scanning, and performing optical path matching between the 2 nd measuring probe internal reflected light (421) and the 2 nd measuring probe emergent light reflected light (422) on the 1 st measuring probe external surface; saving the signal m10 acquired by the 1 st photodetector (703) and the signal m20 acquired by the 2 nd photodetector (704);
and (3): demodulating a signal m10 acquired by the 1 st photoelectric detector, a signal m20 acquired by the 2 nd photoelectric detector, a signal m30 acquired by the 3 rd photoelectric detector and a signal m40 acquired by the 4 th photoelectric detector to obtain a double optical path H between the 1 st measuring probe and the 2 nd measuring probe;
and (4): if the thickness of the opaque film to be measured (403) is measured, opening a 1 st optical switch (405) and a 2 nd optical switch (406), inserting the opaque film to be measured (403) between a 1 st measuring probe (401) and a 2 nd measuring probe (402), and enabling the opaque film to be measured (403) to be vertical to emergent rays of the 1 st measuring probe (401) and the 2 nd measuring probe (402) at the same time; driving an optical path scanning device (603) to perform optical path scanning, so that optical path matching is performed on the 1 st measuring probe internal reflected light (413) and the 1 st measuring probe emergent light reflected light (414) on the front surface of the opaque film to be measured, and optical path matching is performed on the 2 nd measuring probe internal reflected light (423) and the 2 nd measuring probe emergent light reflected light (424) on the rear surface of the opaque film to be measured; storing a signal m11 collected by the 1 st photoelectric detector, a signal m21 collected by the 2 nd photoelectric detector, a signal m31 collected by the 3 rd photoelectric detector and a signal m41 collected by the 4 th photoelectric detector;
and (5): demodulating a signal m11 acquired by the 1 st photoelectric detector, a signal m21 acquired by the 2 nd photoelectric detector, a signal m31 acquired by the 3 rd photoelectric detector and a signal m41 acquired by the 4 th photoelectric detector to respectively obtain a double optical path H1 between the 1 st measuring probe and the front surface of the film to be measured and a double optical path H2 between the 2 nd measuring probe and the front surface of the film to be measured;
and (6): calculating the thickness d1 of the opaque film to be measured:
and (7): if the thickness of the transparent film is measured, opening a 1 st optical switch (405), closing a 2 nd optical switch (406), inserting the transparent film to be measured (404) between a 1 st measuring probe (401) and a 2 nd measuring probe (402), and enabling the transparent film to be measured (404) to be vertical to emergent rays of the 1 st measuring probe (401) and the 2 nd measuring probe (402); driving an optical path scanning device (603) to perform optical path scanning, enabling light reflected by the inside of a 1 st measuring probe (415), light reflected by the emergent light of the 1 st measuring probe on the front surface of the transparent film to be measured (416) and light reflected by the emergent light of the 1 st measuring probe on the rear surface of the transparent film to be measured (417) to be subjected to optical path matching respectively, and storing a signal m32 collected by a 3 rd photoelectric detector and a signal m42 collected by a 4 th photoelectric detector;
and (8): closing a 1 st optical switch (405), opening a 2 nd optical switch (406), driving an optical path scanning device (603) to perform optical path scanning, respectively performing optical path matching on the internal reflected light (425) of a 2 nd measuring probe, the reflected light (426) of the emergent light of the 2 nd measuring probe on the rear surface of the transparent film to be measured and the reflected light (427) of the emergent light of the 2 nd measuring probe on the front surface of the transparent film to be measured, and storing a signal m12 collected by a 1 st photoelectric detector and a signal m22 collected by a 2 nd photoelectric detector (704);
and (9): demodulating a signal m12 acquired by the 1 st photoelectric detector, a signal m22 acquired by the 2 nd photoelectric detector, a signal m32 acquired by the 3 rd photoelectric detector and a signal m42 acquired by the 4 th photoelectric detector to obtain a double optical path H3 between the 1 st measuring probe and the front surface of the transparent film to be measured and a double optical path H4 between the 1 st measuring probe and the rear surface of the transparent film to be measured, and obtaining a double optical path H5 between the 2 nd measuring probe and the rear surface of the transparent film to be measured and a double optical path H6 between the 2 nd measuring probe and the front surface of the transparent film to be measured;
step (10): calculating the thickness d2 of the transparent film (404) to be measured:
when the air refractive index is 1, the refractive index n of the transparent film to be measured (404) is:
2. the method for measuring the thickness and the refractive index of the common-path self-calibration film for eliminating the transmitted light according to claim 1, wherein: the 1 st measuring probe (401) and the 2 nd measuring probe (402) have the same optical parameters, and the 1 st optical switch (405) and the 2 nd optical switch (406) have the same optical parameters;
the process of generating the wide-spectrum light interference signal comprises the following steps: (1) when the optical path difference of the two arms is equal to 2H, the light in the scanning arm is matched with the light in the fixed arm, and a 1 st maximum white light interference signal is generated; (2) when the optical path difference of the two arms is equal to 0, light in the scanning arm and the fixed arm is matched, and a main maximum white light interference signal is generated; (3) when the optical path difference of the two arms is equal to-2H, the light in the scanning arm is matched with the light in the fixed arm, and a 2 nd maximum white light interference signal is generated; (4) by extracting the position of the central fringe of the white light interference signal, the absolute difference of the scanning distance between the major maximum and the minor maximum is obtained by utilizing the tracing characteristic of the laser interference signal, and the absolute difference represents the absolute double optical path between the 1 st measuring probe and the 2 nd measuring probe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810084488.9A CN108317962B (en) | 2018-01-29 | 2018-01-29 | Method for measuring thickness and refractive index of common-path self-calibration film for eliminating transmitted light |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810084488.9A CN108317962B (en) | 2018-01-29 | 2018-01-29 | Method for measuring thickness and refractive index of common-path self-calibration film for eliminating transmitted light |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108317962A CN108317962A (en) | 2018-07-24 |
| CN108317962B true CN108317962B (en) | 2020-04-07 |
Family
ID=62888091
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810084488.9A Active CN108317962B (en) | 2018-01-29 | 2018-01-29 | Method for measuring thickness and refractive index of common-path self-calibration film for eliminating transmitted light |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108317962B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113340818B (en) * | 2021-06-02 | 2022-08-05 | 天津大学 | Self-consistent verification differential spectrometer and measurement method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102589452A (en) * | 2012-01-17 | 2012-07-18 | 华南师范大学 | Method and device for measuring thickness and refractive index of thin film |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6482669B1 (en) * | 2001-05-30 | 2002-11-19 | Taiwan Semiconductor Manufacturing Company | Colors only process to reduce package yield loss |
| JP4622564B2 (en) * | 2005-02-10 | 2011-02-02 | 凸版印刷株式会社 | Film thickness measurement method |
| JP5168168B2 (en) * | 2009-01-22 | 2013-03-21 | パナソニック株式会社 | Refractive index measuring device |
| CN102183866B (en) * | 2011-05-09 | 2012-08-22 | 哈尔滨工程大学 | Imbalanced-Mach-Zehnder-based demodulation device for multiplexing optical fiber interferometer |
| CN105588661B (en) * | 2015-11-12 | 2018-07-31 | 哈尔滨工程大学 | A kind of device for realizing that single-point and regional temperature measure simultaneously using polarization-maintaining fiber grating |
| CN105865753B (en) * | 2016-05-18 | 2018-04-17 | 哈尔滨工程大学 | A kind of measuring device and measuring method of fibre optic interferometer arm length difference |
| CN106871798A (en) * | 2017-03-09 | 2017-06-20 | 广东工业大学 | The measuring method and system of a kind of film thickness and refractive index |
| CN107339943B (en) * | 2017-04-25 | 2019-09-27 | 哈尔滨工程大学 | The total optical path self calibration apparatus for measuring thickness of thin film and measurement method of palarization multiplexing |
| CN107167085B (en) * | 2017-04-25 | 2019-09-27 | 哈尔滨工程大学 | A kind of optical path self calibration apparatus for measuring thickness of thin film and measurement method altogether |
-
2018
- 2018-01-29 CN CN201810084488.9A patent/CN108317962B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102589452A (en) * | 2012-01-17 | 2012-07-18 | 华南师范大学 | Method and device for measuring thickness and refractive index of thin film |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108317962A (en) | 2018-07-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108426530B (en) | Device and method for simultaneously measuring thickness and refractive index of thin film | |
| CN107339943B (en) | The total optical path self calibration apparatus for measuring thickness of thin film and measurement method of palarization multiplexing | |
| CN106643522A (en) | Optical-fiber low-coherence interference displacement demodulation device and method based on photoelectric oscillator | |
| CN107167085B (en) | A kind of optical path self calibration apparatus for measuring thickness of thin film and measurement method altogether | |
| CN105044035B (en) | Refractive index and thickness method for synchronously measuring and system based on spectral domain interferometer | |
| CN211824859U (en) | Optical fiber air pressure sensor based on dislocation fusion and vernier effect | |
| KR20060102127A (en) | Apparatus for measuring a differential mode delay of a multimode optical fiber | |
| NO982586L (en) | Fiber optic interferometer as optical tapping | |
| CN104330021B (en) | Optical flat self-calibration interference with common path instrument based on acousto-optic heterodyne phase shift | |
| CN104215176A (en) | High accuracy optical interval measurement device and method | |
| CN104807781B (en) | A kind of measuring device of refraction index of air and measuring method based on dispersion interferometric method | |
| CN206787499U (en) | Big spacing lens wearer distance-measuring device | |
| CN108317962B (en) | Method for measuring thickness and refractive index of common-path self-calibration film for eliminating transmitted light | |
| CN111504199A (en) | Scanning displacement platform interference range unit based on microcavity optical comb | |
| CN205003080U (en) | Refracting index and thickness synchronous measurement system based on spectral domain interferometer | |
| CN104792269B (en) | A kind of calculation method of the fiber end face height value insensitive to linear phase-shift error | |
| CN111964580B (en) | Device and method for detecting position and angle of film based on optical lever | |
| EP3423782B1 (en) | Device and method for measuring the parameters of phase elements | |
| CN112082492B (en) | Device and method for simultaneously measuring thickness and refractive index of film with angle monitoring function | |
| CN110030921B (en) | Shearing-quantity-adjustable transmission-type dual-frequency laser differential interference measuring device and method | |
| CN209996294U (en) | device for accurately measuring optical path difference between front and back surfaces of human cornea | |
| CN105115940B (en) | Optical material refractive index curve measuring method and device | |
| CN106840009A (en) | Big spacing lens wearer distance-measuring device and its measuring method | |
| CN111578832A (en) | Short coherent light source interferometer-based long-stroke optical path matching device and experimental method | |
| CN110631509B (en) | Object surface curvature detection system and method based on grating Talbot image |
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 |