CN115164771A - Three-dimensional shape measuring method and device based on wavelength tunable optical field measuring technology - Google Patents
Three-dimensional shape measuring method and device based on wavelength tunable optical field measuring technology Download PDFInfo
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- CN115164771A CN115164771A CN202210952485.9A CN202210952485A CN115164771A CN 115164771 A CN115164771 A CN 115164771A CN 202210952485 A CN202210952485 A CN 202210952485A CN 115164771 A CN115164771 A CN 115164771A
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- 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
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/2441—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures using interferometry
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- G—PHYSICS
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- 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
- G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
- G01B11/161—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge by interferometric means
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Abstract
The invention discloses a three-dimensional shape measuring method and device based on a wavelength tunable optical field measuring technology, and belongs to the technical field of optical precision detection. The measuring device consists of a tunable laser, a first light splitting device, a reflector, a first beam expanding system, a second light splitting device and a camera; the measuring method comprises the steps of irradiating measuring laser on the surface of a measured sample to form a corresponding interferogram, calculating the phase distribution of the surface of the measured sample by using a light field calculating technology, generating a plurality of measuring beams by using a laser tuning technology to realize range expansion, and finally completing the measurement of the three-dimensional appearance of the surface of an object. The invention has the characteristics of wide application range of the roughness of the surface to be detected, strong range adaptability, non-contact, high precision and the like, can realize the nondestructive detection of the piece to be detected, and can be widely applied to the high-precision detection fields of semiconductors, optics, aerospace and the like.
Description
Technical Field
The invention belongs to the technical field of optical precision detection, and particularly relates to a three-dimensional shape measuring method and device based on a wavelength tunable optical field measuring technology.
Background
The high-precision three-dimensional shape measurement technology can be used for testing the shape, deformation and micro-motion amount of products in the fields of optics, semiconductors and confidential machinery, and has important effects in the fields of precision machinery, precision instrument manufacturing, precision optical processing, product detection and the like. With the rapid development of precision manufacturing and processing industries such as semiconductors, chips and the like, the requirements for high-precision detection of the surface three-dimensional surface morphology of various devices are more and more, and the requirements for detection precision are also higher and more, so that a plurality of high-precision detection technologies come into force.
The existing measuring methods are mainly divided into two categories, namely contact measuring methods and non-contact measuring methods. The traditional contact measurement method is represented by a three-coordinate measuring machine and has micrometer-scale measurement accuracy. However, when the object to be measured is a weak rigid or soft material, elastic deformation is caused by contact measurement, measurement errors are introduced, and the high-precision detection requirements of semiconductors, chips and the like cannot be met. Meanwhile, the surface of the measured object may be scratched by the contact measurement method, and the problems that the contact measurement speed is low and the automatic measurement is difficult to realize exist, so that the non-contact detection method is concerned more.
The non-contact three-dimensional shape measuring method mainly comprises stereoscopic vision, micro focusing, laser interference and the like. The stereoscopic vision three-dimensional topography measuring technology uses a plurality of imaging lenses and cameras, and maps the mapping points of the same space physical point in different images through the difference between the obtained images shot by different cameras, and establishes the corresponding relation between the characteristic points, thereby obtaining the surface topography of the object. The method has the advantages of high efficiency, proper precision, simple system structure, low cost and the like, but the detection precision can only reach the sub-millimeter level and cannot meet the requirement of rapid high-precision three-dimensional detection at the present stage. The microscopic fixed-focus three-dimensional topography measurement technology uses a confocal fixed-focus method to carry out accurate non-contact positioning on each position point on the surface to be measured, and combines a three-dimensional scanning mode to realize high-precision measurement on the three-dimensional topography of the measured piece. However, as with a three-coordinate measuring instrument, the microscopic fixed-focus three-dimensional shape measurement technology also has the problem of low measurement speed, and cannot meet the requirements of rapid high-precision three-dimensional detection at the present stage. The laser interference surface type detection technology can quickly obtain the surface type of the detected piece, and the measurement precision reaches the nanometer level, but the method is only suitable for smooth surfaces such as mirror surfaces and the like, has limited range, and is not suitable for surface three-dimensional detection of other pieces.
In summary, the existing measurement method cannot simultaneously meet the requirements of high-precision, rapid and wide-range non-contact three-dimensional shape measurement, and cannot realize the requirement of high-precision detection of three-dimensional surface shapes of devices with different roughness.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a three-dimensional shape measuring method based on a wavelength tunable optical field measuring technology. The method can be used for carrying out wide-range, high-precision and rapid detection on the three-dimensional appearance of the surface of the object and the deformation of the object, and can be widely applied to the high-precision detection fields of semiconductors, optics, aerospace and the like.
The invention is realized by the following technical scheme:
the invention provides a three-dimensional shape measurement method based on a wavelength tunable optical field measurement technology, which comprises the following steps:
s1: opening the tunable laser to emit laser beams, enabling the laser beams to enter the first light splitting device, and then splitting the laser beams into two paths; one path of light passes through the first light splitting device, forms a large-caliber measuring light beam after passing through the reflector and the first beam expanding system, irradiates the surface of a measured sample, and is reflected by the measured sample to form object light; the other path of the reference beam passes through a second beam expanding system to form a reference beam, the reference beam and the object beam are combined by a second beam splitting device and then interfere with each other, an interference pattern is formed on a photosensitive surface of the camera, and the camera collects information of the interference pattern;
s2: by varying the wavelength of the light beam emitted by a tuneable laserλ 1 、λ 2 、…、λ N Multiple measuring beams are respectively irradiated on the surface of the sample to be measured to form corresponding interference patternsI 1 、I 2 、…、I N Performing light field calculation on each interference pattern, and combining a light field diffraction calculation method to obtain the phase distribution of the surface of the measured sampleφ 1 、φ 2 、…、φ N ；
S3: selectingλ 1 、λ 2 、…、λ N Two wavelengths in (1)λ i Andλ j combining to obtain a combined wavelength
Corresponding three-dimensional topography measurements
Whereinφ i Andφ j is a wavelengthλ i Andλ j the measured phase distribution of the measuring beam of (a);
s4: synthesizing a series of different combined wavelengths 1 、Λ 2 、…、Λ K Corresponding three-dimensional topography measurementsh 1 、h 2 、…、h K Obtaining the three-dimensional shape measurement result of the measured sample surface 5 with expanded measuring rangeh S 。
Further, in the method, the inclination angle of the second light splitting device is adjusted to form an included angle between the reference beam and the object light, and then the light field information is extracted from the interference pattern through a Fourier transform method.
Furthermore, in the method, the inclination angle of the second beam splitter is adjusted to make the reference beam consistent with the central optical axis of the object beam, a phase shifter is added in the second beam expanding system and the second beam splitter to shift the phase of the reference beam, and then the light field information is extracted from the hologram by a multi-step phase shift calculation method.
Secondly, the present invention provides a computer-readable storage medium storing a computer program, wherein the computer program in the computer-readable storage medium implements the steps of one of the methods when executed by a processor.
The invention provides a three-dimensional shape measuring device based on a wavelength tunable light field measuring technology, which comprises a tunable laser, a first light splitting device, a reflector, a first beam expanding system, a second light splitting device and a camera, wherein the tunable laser is used for emitting laser light; the first light splitting device is over against a laser emitting port of the tunable laser, the reflector is positioned on a transmission light path of the first light splitting device, the first beam expanding system is positioned on a reflection light path of the reflector, the measured sample is positioned on the transmission light path of the first beam expanding system, the second beam expanding system is positioned on the reflection light path of the first light splitting device, the second light splitting device is positioned at the intersection position of the reflection light path of the measured sample and the transmission light path of the second beam expanding system, and the camera is positioned on a beam combining light path of the second light splitting device.
Furthermore, in the above device, the first beam splitter is a polarization beam splitter and is composed of a first half-wave plate, a polarization beam splitter prism and a second half-wave plate, the first half-wave plate faces the laser emission port of the tunable laser, the polarization beam splitter prism is located on the transmission light path of the first half-wave plate, and the second half-wave plate is located on the reflection light path of the polarization beam splitter prism.
Further, in the above apparatus, a phase shift device is provided between the first beam splitting device and the second beam expanding system.
The invention provides a third device for measuring three-dimensional morphology based on a wavelength tunable light field measurement technology, wherein the third device is used for replacing a first beam expanding system and a second beam expanding system on the basis of the first device, namely the second device comprises a tunable laser, a first light splitting device, a reflector, a third beam expanding system, a second light splitting device and a camera; the third beam expanding system faces a laser emitting port of the tunable laser, the first light splitting device is positioned on a transmission light path of the third beam expanding system, the reflector is positioned on the transmission light path of the first light splitting device, the sample to be measured is positioned on a reflection light path of the reflector, the second light splitting device is positioned at a crossed position on a reflection light path of the sample to be measured and a reflection light path of the first light splitting device, and the camera is positioned on a beam combining light path of the second light splitting device; the light beam emitted by the tunable laser passes through the third beam expanding system and then is divided into two paths by the first light splitting device, the light penetrating through the first light splitting device is reflected by the reflecting mirror and then irradiates on a tested sample, and the light reflected by the first light splitting device directly enters the second light splitting device.
The invention provides a third three-dimensional morphology measuring device based on a wavelength tunable light field measuring technology, which comprises a tunable laser, a third beam expanding system, a first light splitting device, a reflector, a second light splitting device, a third light splitting device and a camera; the third beam expanding system and the first beam splitting device are right opposite to a laser emitting port of the tunable laser, the reflecting mirror is located on a reflecting light path of the first beam splitting device, the second beam splitting device is located on a transmitting light path of the first beam splitting device, the measured sample is located on a reflecting light path of the second beam splitting device, the third beam splitting device is located at the intersection position of a reflecting light path of the measured sample and a reflecting light path of the reflecting mirror, and the camera is located on a beam combining light path of the third beam splitting device.
Further, in the above device, a first collecting mirror is disposed between the second light splitting device and the third light splitting device, a diaphragm is disposed at a focal position of the first collecting mirror, and a second collecting mirror is disposed between the reflecting mirror and the third light splitting device.
The method combines a wavelength tunable technology and an optical field measurement technology, obtains the phase distribution of the surface of the measured sample through the optical field measurement technology, generates a plurality of measuring beams through the laser tuning technology to realize range expansion, and finally completes the measurement of the three-dimensional appearance of the surface of the object. The invention can be applied to displacement measurement of objects with mirror surfaces or rough surfaces, and realizes wide-range, high-precision and quick detection of the three-dimensional appearance of the surfaces of the objects and the deformation of the objects.
Compared with the prior art, the invention has the following innovation points and obvious advantages:
1) The invention provides a wavelength tunable optical field measurement technology for the first time, and the synthetic wavelength value required at will is customized by regulating the size of the wavelength, so that the measurement range of the system is quickly adjusted to the measurement range suitable for an object to be measured, and the problem that the fixed wavelength laser cannot take into account the measurement requirements of different measurement ranges is solved;
2) A series of different combined wavelengths are generated through the combination of a series of different laser wavelengths, and the different combined wavelengths correspond to different measuring ranges and measuring accuracies, so that the combination of the measuring results under different combined wavelengths can simultaneously meet the requirement of wide-range high-accuracy measurement on the object to be measured;
3) The invention can meet the measurement requirements of objects to be measured with different surface materials, and has wide application range for measuring the surface roughness;
4) The measuring method has the characteristics of full-field and non-contact measurement, and can realize the nondestructive detection of the to-be-measured piece.
Drawings
Fig. 1 is a schematic structural diagram of a measurement apparatus in embodiment 1 of the present invention.
Fig. 2 is a schematic structural diagram of a measurement apparatus in embodiment 2 of the present invention.
Fig. 3 is a schematic structural diagram of a measurement apparatus in embodiment 3 of the present invention.
Fig. 4 is a schematic structural diagram of the polarization splitting device in fig. 3.
Fig. 5 is a schematic structural diagram of a measuring apparatus in embodiment 4 of the present invention.
Fig. 6 is a schematic structural diagram of a measurement apparatus in embodiment 5 of the present invention.
Fig. 7 is a schematic structural diagram of a measurement apparatus in embodiment 6 of the present invention.
In the figure: the method comprises the following steps of 1-a tunable laser, 2-a first beam splitting device, 3-a reflector, 4-a first beam expanding system, 5-a sample to be measured, 6-a second beam expanding system, 7-a second beam splitting device, 8-a camera, 9-a phase shifting device, 10-a polarization beam splitting device, 1001-a first half wave plate, 1002-a polarization beam splitting prism, 1003-a second half wave plate, 11-a third beam expanding system, 12-a third beam splitting device, 13-a first collecting mirror, 14-a diaphragm and 15-a second collecting mirror.
Detailed Description
The invention is further illustrated by the following figures and examples.
The invention uses the wavelength tunable optical field measurement technology, customizes the synthesis wavelength value of any requirement by regulating the wavelength, and different combination wavelengths correspond to different measurement ranges and measurement precision, so that the combination of the measurement results under different combination wavelengths can simultaneously meet the requirement of wide-range high-precision measurement on the object to be measured.
Example 1
The embodiment utilizes the wavelength tunable optical field measurement technology to realize the rapid high-precision measurement of the three-dimensional topography of the rough surface. As shown in fig. 1, the measuring apparatus in this embodiment is a three-dimensional topography measuring apparatus based on a wavelength tunable optical field measurement technique, and its structure includes: the device comprises a tunable laser 1, a first light splitting device 2, a reflecting mirror 3, a first beam expanding system 4, a second beam expanding system 6, a second light splitting device 7 and a camera 8.
The tunable laser 1 generates measurement laser light, which is incident on the first beam splitting device 2.
The tunable laser 1 uses a coherent light source, and the wavelength of the outgoing laser can be changed by a laser wavelength tuning technique. In this embodiment, the tunable laser 1 can emit a test laser with a wavelength range of 532-542nm, and the aperture of the light beam is 2mm.
The first light splitting device 2 and the second light splitting device 7 are the same, and have the aperture of 25.4mm and the transmission inverse ratio of 1: the beam splitter prism of 1 can split the measuring beam entering the prism into two beams with the same intensity and vertical outgoing direction.
The measuring beam emitted by the tunable laser 1 is split into two paths after passing through the first light splitting device 2, and the transmitted beam is incident on the reflecting mirror 3. The mirror 3 is used to reflect light and deflect the propagation direction of the measuring beam. The transmitted beam is reflected by the mirror 3 and then incident on the first beam expanding system 4.
The beam expanding multiplying power of the first beam expanding system 4 is 4X, a measuring beam with a large caliber can be formed, and the caliber of the expanded measuring laser beam is 8mm. The system adopts a two-piece structure, and the focal lengths of the lenses are respectively 5mm and 20mm.
The expanded measuring beam irradiates the surface of the measured sample 5 and is reflected by the measured sample 5 to form object light.
The light beam reflected from the first beam splitting device 2 passes through a second beam expanding system 6 to form a reference beam. The second beam expanding system 6 has the same parameters as the first beam expanding system 4, adopts a two-piece structure, the focal lengths of the lenses are respectively 5mm and 20mm, and the beam expanding multiplying power is 4X.
The object light and the reference light beam are combined by the second beam expanding system 6 to form an interference pattern on a photosensitive surface of the camera 8, and the camera 8 collects information of the interference pattern. The second beam expanding system 6 is a flat crystal having an aperture of 30mm and a transmittance of 50%. The camera 8 is used to record the interference pattern, and the camera 8 includes but is not limited to CCD, CMOS, etc.
In this embodiment, the laser beam transmitted by the first beam splitter 2 is finally incident on the camera 8 through the mirror 3, the first beam expanding system 4, the sample 5 to be measured, and the second beam splitter 7, and this part of light may be referred to as object light.
In this embodiment, the laser beam reflected by the first beam splitter 2 passes through the second beam expander system 6 and the second beam splitter 7 and finally enters the camera 8, and this part of the laser beam may be referred to as reference light.
The three-dimensional topography measuring device based on the wavelength tunable optical field measurement technology used in this embodiment can realize high-precision and rapid detection of the three-dimensional topography of the surface of an object and the deformation of the object, and the specific measurement steps are as follows:
s1: placing a tested sample 5 in a test light path;
s2: the tunable laser 1 is driven to change the wavelength of the light beam emitted by the tunable laser, so that 532nm, 534.845nm and 561.892nm measuring light beams are formed and respectively irradiated on the surface of a measured sample 5 to form a corresponding interference patternI 1 、I 2 、I 3 (ii) a Adjusting the inclination angle of the second light splitting device 7 to form an included angle between the reference beam and the object beam, and further extracting light field information from the interference pattern by a Fourier transform method; obtaining the phase distribution phi of the surface of the tested sample 5 by combining a light field diffraction calculation method 1 、φ 2 、φ 3 ；
S3: using formulas
Selecting 532nm and 534.845nm, 532nm and 561.892nm to be combined to obtain corresponding combined wavelength Λ 1 =100μm，Λ 2 =10um; using formulas
To obtain Λ 1 、Λ 2 Corresponding three-dimensional topography measurement h 1 、h 2 ；
S4: synthesizing two combined wavelengths 1 、Λ 2 Corresponding three-dimensional topography measurement h 1 、h 2 Obtaining the measurement result h of the three-dimensional surface topography of the measured sample 5 with expanded measuring range S 。
Example 2
Unlike embodiment 1, this embodiment performs the phase of the interference fringe and the optical field solution by a four-step phase-shift method. As shown in fig. 2, the measuring apparatus in this embodiment is a three-dimensional topography measuring apparatus combining a phase shift interference optical field testing technique, and its structure includes: the device comprises a tunable laser 1, a first light splitting device 2, a reflecting mirror 3, a first beam expanding system 4, a second beam expanding system 6, a second light splitting device 7, a camera 8 and a phase shifting device 9. The phase-shifting device 9 is a micro-motion device composed of piezoelectric ceramics, and can shift the phase of the reference light according to the requirements of the wavelength and the number of phase-shifting steps of the test laser, and further extract the light field information from the interferogram by a phase calculation method.
The optical path working principle of the three-dimensional topography measuring device used in this embodiment in combination with the item shifting interference optical field testing technology is as follows:
the tunable laser 1 generates measuring laser, and the measuring laser is changed into two paths after being incident to the first light splitting device 2: the first path of transmitted light is called object light, and irradiates a sample 5 to be measured after passing through a reflector 3 and a first beam expanding system 4, and measurement laser reflected by the surface of the sample 5 to be measured passes through a second light splitting device 7 and finally reaches a camera 8; the second path of reference beam passes through the second beam expanding system 6 and the phase shifting device 9, is reflected by the second beam splitting device 7, finally reaches the camera 8, forms interference with the object light, and is recorded by the camera.
The three-dimensional topography measuring device used in this embodiment and combined with the phase shift interference optical field testing technology includes the following steps:
s1: placing a tested sample 5 in a test light path;
s2: the tunable laser 1 emits a measuring beam with a wavelength of 532nm, which is recorded as wavelength lambda 1 The phase shift device 9 is driven to form a phase shift interference pattern with a phase difference of 1/4 wavelengthI 11 、I 12 、I 13 、I 14 Combining a light field diffraction calculation method and a phase unwrapping method to obtain the phase distribution phi on the surface of the sample 5 to be measured 1 ；
S3: the tunable laser 1 is driven to change the wavelength of the light beam emitted by the tunable laser, and the measuring light beams with the wavelengths of 534.845nm and 561.892nm respectively irradiate the surface of the sample 5 to be measured; simultaneously driving a phase shift device 9 to form phase shift interferograms with a phase difference of 1/4 wavelength for each wavelength, and recording the corresponding interferograms asI 21 、I 22 、I 23 、I 24 ，I 31 、I 32 、I 33 、I 34 The optical field is calculated for the interferogram with the same wavelength, and the phase distribution phi of the surface of the tested sample 5 is obtained by combining the optical field diffraction calculation method 2 、φ 3 ；
S4: using formulas
Selecting 532nm and 534.845nm, 532nm and 561.892nm to be combined to obtain corresponding combined wavelength Λ 1 =100μm，Λ 2 =10um; using formulas
To obtain Λ 1 、Λ 2 Corresponding three-dimensional topography measurement h 1 、h 2 ；
S5: synthesizing two combined wavelengths 1 、Λ 2 Corresponding three-dimensional topography measurement h 1 、h 2 Obtaining the measurement result h of the three-dimensional surface topography of the measured sample 5 with expanded measuring range S 。
Example 3
The embodiment utilizes the wavelength tunable optical field measurement technology to realize the rapid high-precision measurement of the three-dimensional topography of the rough surface. As shown in fig. 3, the measuring apparatus in this embodiment is a three-dimensional topography measuring apparatus using a polarization beam splitter, and its structure includes: the device comprises a tunable laser 1, a polarization beam splitter 10, a reflector 3, a first beam expanding system 4, a second beam expanding system 6, a second beam splitter 7 and a camera 8.
Unlike embodiment 1, the present embodiment uses a polarization beam splitter 10, which can split the laser beam emitted from the tunable laser 1 into two paths and adjust the light intensity ratio of the two paths of light. (typically 1:5 to 5:1). The polarization beam splitter 10 is an embodiment of the first beam splitter 2, and as shown in fig. 4, the polarization beam splitter 10 is composed of a first half-wave plate 1001, a polarization beam splitter prism 1002, and a second half-wave plate 1003, where the first half-wave plate 1001 faces the laser emission port of the tunable laser 1, the polarization beam splitter prism 1002 is located on the transmission light path of the first half-wave plate 1001, and the second half-wave plate 1003 is located on the reflection light path of the polarization beam splitter prism 1002.
In this embodiment, the light intensity ratio (generally 1:5-5:1) between the reflected light and the transmitted light can be changed by rotating and adjusting the first half-wave plate 1001 in the polarization beam splitter 10, so as to perform the function of adjusting the light intensity ratio between the object light and the reference light, thereby obtaining a high-quality interference pattern. By rotating the second half-wave plate 1003, the polarization directions of the object light and the reference light are made to coincide in order to enable the two to interfere.
Example 4
As shown in fig. 5, the measuring apparatus adopted in this embodiment is another three-dimensional topography measuring apparatus combining a phase shift interference optical field testing technique, and its structure includes: the device comprises a tunable laser 1, a first light splitting device 2, a reflecting mirror 3, a first beam expanding system 4, a second beam expanding system 6, a second light splitting device 7, a phase shifting device 9 and a camera 8. Unlike embodiment 2, in this embodiment, the phase shifting device 9 is disposed between the first beam splitting device 2 and the second beam expanding system 6.
Example 5
As shown in fig. 6, the measuring apparatus adopted in this embodiment is a three-dimensional profile measuring apparatus under a single beam expanding system, and the structure thereof includes: the device comprises a tunable laser 1, a third beam expanding system 11, a first light splitting device 2, a reflecting mirror 3, a second light splitting device 7, a third light splitting device 12 and a camera 8;
the third beam expanding system 11 and the first beam splitting device 2 are over against a laser emitting port of the tunable laser 1, the reflector 3 is located on a reflection light path of the first beam splitting device 2, the second beam splitting device 7 is located on a transmission light path of the first beam splitting device 2, the object to be measured is located on a reflection light path of the second beam splitting device 7, the third beam splitting device 12 is located at a crossing position of the reflection light path of the object to be measured and the reflection light path of the reflector 3, and the camera 8 is located on a beam combining light path of the third beam splitting device 12.
Example 6
As shown in fig. 7, the measuring apparatus adopted in this embodiment is a three-dimensional profile measuring apparatus with pinhole filtering, and its structure includes: the device comprises a tunable laser 1, a third beam expanding system 11, a first light splitting device 2, a reflecting mirror 3, a second light splitting device 7, a third light splitting device 12, a first collecting mirror 13, a diaphragm 14 and a camera 8; unlike embodiment 5, in this embodiment, the first collecting mirror 13 is placed between the second light splitting device 7 and the third light splitting device 12, the diaphragm 14 is placed at the focal point of the first collecting mirror 13, and the second collecting mirror 15 is placed between the reflecting mirror 3 and the third light splitting device 12.
Example 7
A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the method steps of:
s1: the processor controls the tunable laser to be turned on to emit laser beams, so that the laser beams enter the first light splitting device and are then split into two paths; one path of light passes through the first light splitting device, forms a large-caliber measuring light beam after passing through the reflector and the first beam expanding system, irradiates the surface of a measured sample, and is reflected by the measured sample to form object light; the other path of the reference beam passes through a second beam expanding system to form a reference beam, the reference beam and the object beam are combined by a second beam splitting device and then interfere with each other, an interference pattern is formed on a photosensitive surface of the camera, and the camera collects information of the interference pattern;
s2: the processor controls the wavelength of the light beam emitted by the tunable laser to change, and formsλ 1 、λ 2 、…、λ N Multiple measuring beams are respectively irradiated on the surface of the sample to be measured to form corresponding interference patternsI 1 、I 2 、…、I N Performing light field calculation on each interference pattern, and combining a light field diffraction calculation method to obtain the phase distribution of the surface of the measured sampleφ 1 、φ 2 、…、φ N ；
S3: selectingλ 1 、λ 2 、…、λ N Two wavelengths in (1)λ i Andλ j combining to obtain a combined wavelength
Corresponding three-dimensional topography measurements
Whereinφ i Andφ j is a wavelengthλ i Andλ j the measured phase distribution of the measuring beam of (1);
s4: synthesizing a series of different combined wavelengths 1 、Λ 2 、…、Λ K Corresponding three-dimensional topography measurementsh 1 、h 2 、…、h K Obtaining the three-dimensional shape measurement result of the measured sample surface 5 with expanded measuring rangeh S 。
Claims (10)
1. A three-dimensional shape measurement method based on a wavelength tunable optical field measurement technology is characterized in that: the method comprises the following measuring steps:
s1: a light beam emitted by the tunable laser is divided into two paths after passing through the first light splitting device, wherein one path of light beam sequentially passes through the reflector and the first beam expanding system to form a large-caliber measuring light beam which is irradiated on the surface of a measured sample and reflected by the measured sample to form object light; the other path of the reference beam passes through a second beam expanding system to form a reference beam, the reference beam and the object beam are combined by a second beam splitting device and then interfere with each other, an interference pattern is formed on a photosensitive surface of the camera, and the camera collects information of the interference pattern;
s2: by varying the wavelength of the light beam emitted by the tunable laserλ 1 、λ 2 、…、λ N Multiple measuring beams are respectively irradiated on the surface of the sample to be measured to form corresponding interference patternsI 1 、I 2 、…、I N Performing light field calculation on each interference pattern, and combining a light field diffraction calculation method to obtain the phase distribution of the surface of the measured sampleφ 1 、φ 2 、…、φ N ；
S3: selectingλ 1 、λ 2 、…、λ N Two wavelengths in (1)λ i Andλ j the combination is carried out, and the combination is carried out,obtaining three-dimensional shape measurement results corresponding to the combined wavelengths
Whereinφ i Andφ j is a wavelengthλ i Andλ j the measured phase distribution of the measuring beam of (1);
s4: synthesizing a series of different combined wavelengths 1 、Λ 2 、…、Λ K Corresponding three-dimensional topography measurementsh 1 、h 2 、…、h K Obtaining the three-dimensional shape measurement result of the measured sample surface 5 with expanded measuring rangeh S 。
2. The three-dimensional topography measurement method based on the wavelength tunable optical field measurement technique according to claim 1, characterized in that: and adjusting the inclination angle of the second light splitting device to form an included angle between the reference beam and the object light, and further extracting light field information from the interference pattern by a Fourier transform method.
3. The three-dimensional topography measurement method based on the wavelength tunable optical field measurement technique according to claim 1, characterized in that: and adjusting the inclination angle of the second beam splitter to enable the reference beam to be consistent with the central optical axis of the object beam, adding a phase shifter into the second beam expanding system and the second beam splitter to shift the phase of the reference beam, and further extracting the light field information from the hologram by a multi-step phase shift calculation method.
4. A computer-readable storage medium, in which a computer program is stored which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 3.
5. A three-dimensional shape measuring device based on wavelength tunable optical field measurement technology is characterized in that: the device comprises a tunable laser, a first light splitting device, a reflector, a first beam expanding system, a second light splitting device and a camera;
the first light splitting device is over against a laser emitting port of the tunable laser, the reflector is positioned on a transmission light path of the first light splitting device, the first beam expanding system is positioned on a reflection light path of the reflector, the measured sample is positioned on the transmission light path of the first beam expanding system, the second beam expanding system is positioned on the reflection light path of the first light splitting device, the second light splitting device is positioned at the intersection position of the reflection light path of the measured sample and the transmission light path of the second beam expanding system, and the camera is positioned on a beam combining light path of the second light splitting device.
6. The three-dimensional topography measurement device based on the wavelength tunable optical field measurement technique according to claim 5, wherein: the first light splitting device is composed of a first half-wave plate, a polarization light splitting prism and a second half-wave plate, the first half-wave plate is right opposite to a laser emission port of the tunable laser, the polarization light splitting prism is located on a transmission light path of the first half-wave plate, and the second half-wave plate is located on a reflection light path of the polarization light splitting prism.
7. The three-dimensional topography measurement device based on the wavelength tunable optical field measurement technique according to claim 5, wherein: a phase shifting device is arranged between the first beam splitting device and the second beam expanding system.
8. A three-dimensional shape measuring device based on wavelength tunable optical field measurement technology is characterized in that: the device comprises a tunable laser, a first light splitting device, a reflector, a third beam expanding system, a second light splitting device and a camera;
the third beam expanding system faces a laser emitting port of the tunable laser, the first light splitting device is located on a transmission light path of the third beam expanding system, the reflector is located on the transmission light path of the first light splitting device, the measured sample is located on a reflection light path of the reflector, the second light splitting device is located at a crossing position on a reflection light path of the measured sample and a reflection light path of the first light splitting device, and the camera is located on a beam combining light path of the second light splitting device.
9. A three-dimensional shape measuring device based on wavelength tunable optical field measurement technology is characterized in that: the device comprises a tunable laser, a third beam expanding system, a first light splitting device, a reflector, a second light splitting device, a third light splitting device and a camera;
the third beam expanding system and the first beam splitting device are opposite to a laser emitting port of the tunable laser, the reflecting mirror is positioned on a reflecting light path of the first beam splitting device, the second beam splitting device is positioned on a transmitting light path of the first beam splitting device, the sample to be measured is positioned on a reflecting light path of the second beam splitting device, the third beam splitting device is positioned at the intersection position of a reflecting light path of the sample to be measured and a reflecting light path of the reflecting mirror, and the camera is positioned on a beam combining light path of the third beam splitting device.
10. The three-dimensional topography measurement device based on the wavelength tunable optical field measurement technique according to claim 9, wherein: and a first collecting mirror is arranged between the second light splitting device and the third light splitting device, a diaphragm is arranged at the focal point of the first collecting mirror, and a second collecting mirror is arranged between the reflecting mirror and the third light splitting device.
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| CN116045835A (en) * | 2023-03-31 | 2023-05-02 | 成都太科光电技术有限责任公司 | Ultra-large caliber plane or spherical surface optical interference testing device |
| CN116045835B (en) * | 2023-03-31 | 2023-06-02 | 成都太科光电技术有限责任公司 | Ultra-large caliber plane or spherical surface optical interference testing device |
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