CN112731344A - Amplified area array sweep frequency distance measuring/thickness measuring device and method with active optical anti-shake function - Google Patents
Amplified area array sweep frequency distance measuring/thickness measuring device and method with active optical anti-shake function Download PDFInfo
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- G—PHYSICS
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
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- G—PHYSICS
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Abstract
The invention discloses an amplification type area array sweep frequency distance measuring/thickness measuring device with active optical anti-shake function, relating to the field of laser sweep frequency distance measuring, comprising a first dichroic mirror, a second dichroic mirror, a beam splitter and a lens, the camera, the spectrum appearance, collection control unit and movable reflection device, establish the beam splitter on the transmitted light direction of first dichroic mirror, establish the objective table on the beam splitter reflected light direction, establish the camera lens between objective table and the beam splitter, the beam splitter has four ports, first port is just to first dichroic mirror, the second port is just to the camera lens, the third port is just to movable reflection device, the fourth port is just to second dichroic mirror, set up the camera on the second dichroic mirror transmitted light direction, the camera links to each other with collection control unit, establish the spectrum appearance on the second dichroic mirror reflected light direction, spectrum appearance intercommunication collection control unit, collection control unit has the signal of gathering camera and spectrum appearance and the function of display data. The device has the advantages of simple structure, quick measurement and high measurement precision.
Description
Technical Field
The invention belongs to the field of laser frequency sweep distance measurement, and particularly relates to an amplification type area array frequency sweep distance measurement/thickness measurement device and method with an active optical anti-shake function.
Background
In modern industrial production, the precision degree of part processing becomes more and more the key of high-performance equipment, and it is very important to accurately and stably produce parts with required specific sizes and shapes. Therefore, accurate detection of the produced parts is an important link for ensuring high-quality production.
In the prior art, application number 201910648603.5 discloses a patent application entitled "an object surface three-dimensional coordinate measuring system and a measuring method", wherein a processor is used for analyzing and processing interference signals among lasers returned by a measuring arm, a first reference arm and a second reference arm so as to obtain the depth of an object to be measured in the Z-axis direction, and is also used for generating a three-dimensional coordinate of the object to be measured in an XY plane coordinate in combination with the object to be measured reacted by a two-dimensional displacement platform. The measurement speed is also limited by the scanning speed, and it is difficult to obtain a high measurement speed at the same time of high sensitivity, which is determined by the characteristics of the point scanning. In the measuring process, due to the influence of the external environment and the operation process, the relevant optical elements can shake, so that the measuring result has certain errors.
An english article entitled "Performance analysis of a full-field and full-range spread-source OCT system" discloses an area-array tomography system with swept-source as core device and cameras, microscopes, and sleeve lenses. However, it has the following disadvantages: the LSR used in the system is a moving speckle attenuator, and the working principle of the LSR is that a camera receives a plurality of optical phases within one exposure time through the vibration of an element up to hundreds of hertz, so that speckles are inhibited. Therefore, in this operation mode, the frame rate of the camera must be tens of times slower than that of the LSR to achieve the speckle suppression effect, and the faster the camera is, the worse the suppression effect is. The dynamic method for suppressing speckle severely limits the photographing speed of the camera, and thus becomes a bottleneck that the ranging system is difficult to measure at a high speed. And the design of the microscope is adopted, so that the method cannot be applied to a single distance measurement scene of a large-size object.
Therefore, there is a need to develop a large-scale, high-precision, fast method for measuring the thickness and distance of an object without point scanning the sample.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide an amplification type area array frequency scanning distance measuring/thickness measuring device with an active optical anti-shake function, and aims to solve the problems of low measuring speed and low measuring precision of a device and a method for measuring the thickness or distance of several millimeters to dozens of micrometers in the prior art.
In order to achieve the above object, the present invention provides an amplified area array frequency-sweep ranging/thickness measuring device with active optical anti-shake function, which comprises a first dichroic mirror, a beam splitter, a second dichroic mirror, a lens, a camera, a spectrometer, an acquisition control unit and a movable reflection device, wherein,
a beam splitter is arranged in the transmission light direction of the first dichroic mirror, an objective table is arranged in the reflection light direction of the beam splitter and used for placing a sample to be measured for distance or thickness, a lens is arranged between the objective table and the beam splitter, a movable reflection device is arranged in the transmission light direction of the beam splitter,
the beam splitter has four ports, the four ports are respectively positioned on four sides of the rectangle, the first port and the third port are positioned on two opposite sides, the first port is over against the first dichroic mirror, the second port is over against the lens, the third port is over against the movable reflection device, the second dichroic mirror is arranged in the direction of the fourth port,
the camera is arranged in the transmission light direction of the second dichroic mirror and connected with the acquisition control unit, the spectrometer is arranged in the reflection light direction of the second dichroic mirror and communicated with the acquisition control unit, and the acquisition control unit has the functions of acquiring signals of the camera and the spectrometer and displaying data.
Further, during operation, still set up the parallel light that is used for realizing the area array sweep frequency in order to range finding or thickness measurement in the transmitted light direction of first dichroic mirror, this parallel light sets up respectively in the both sides of first dichroic mirror with the beam splitter, is provided with the parallel light that is used for realizing optics anti-shake in the reverberation direction of first dichroic mirror for the parallel light that realizes optics anti-shake is located two mutually perpendicular's of first dichroic mirror reverberation direction respectively with the beam splitter.
Further, the device also comprises a tunable laser, a first collimator, a beam expander, a broad spectrum light source and a second collimator, wherein the first collimator and the beam expander are sequentially arranged in the emergent light direction of the tunable laser, the beam expander is just opposite to one side of the first dichroic mirror, the beam expander and the beam splitter are respectively positioned on two sides of the first dichroic mirror,
and a second collimator is arranged in the emergent light direction of the broad-spectrum light source, and the second collimator and the beam splitter are respectively positioned in two mutually perpendicular reflected light directions of the first dichroic mirror.
And a third collimator is arranged between the second dichroic mirror and the spectrometer, and a light filter is arranged between the movable reflecting device and the beam splitter and is a neutral light filter for attenuating light intensity.
Furthermore, the wavelength value of the wide-spectrum light source is 1525 nm-1575 nm or 1290 nm-1330 nm, the wavelength of the wide-spectrum light source is different from that of the tunable laser, and the light emitted by the wide-spectrum light source and the light emitted by the tunable laser pass through the first dichroic mirror and the second dichroic mirror in the light path to converge or split the beams.
Further, the optical system further comprises a lens, wherein the lens is an amplification type telecentric lens, when light reflected by the sample to be detected is still larger than a photosensitive surface of the camera after passing through the lens or the light reflected by the sample to be detected cannot be directly imaged onto a sensor of the camera, the lens is arranged between the second dichroic mirror and the camera, the lens is the telecentric lens and plays a role in reducing the image formed by the lens and imaging the image to the camera, and the distance between the first lens and the second lens is preferably 100 mm. Furthermore, the acquisition control unit is electrically connected with the tunable laser so as to control the tunable laser through an electric signal, the beam expander is used for expanding the light beam to a light spot of 20-40 mm, the lens and the lens are both provided with an adjustable aperture, and when the camera works, the speckle phenomenon occurring on the camera can be improved by adjusting the aperture to a proper size.
Furthermore, the movable reflection device is arranged on the piezoelectric ceramic displacement table, and the piezoelectric ceramic displacement table is connected with the acquisition control unit to move under the control of the acquisition control unit, so that the movable reflection device is driven to move.
According to a second aspect of the present invention, there is also provided a method for measuring distance or thickness by using the distance/thickness measuring device, comprising the steps of:
s1: starting the tunable laser, the broad spectrum light source, the spectrometer and the acquisition control unit to fully preheat the tunable laser, the broad spectrum light source, the spectrometer and the acquisition control unit,
s2: placing the object to be measured on an object stage, adjusting the position of the object stage to enable the light beam emitted by the tunable laser to cover the object to be measured as much as possible, adjusting the first collimator to enable the light emitted by the broad-spectrum light source to irradiate the object to be measured,
s3: the spectrum collected by the spectrometer is processed by Fourier transform data to obtain a transform spectrum, the distance of a sample to be measured is obtained by a signal peak in the transform spectrum, a plurality of distances are obtained by measuring for a plurality of times, the measured distance is changed due to optical jitter, the acquisition control unit drives the movable reflector to move according to the variation of the measured distance to compensate vibration and realize the optical anti-jitter function,
the step S3 is continuously performed during the whole process of distance measurement or thickness measurement to compensate the optical vibration in real time, realize optical anti-shake,
s4: starting the sweep tunable laser, starting to sweep frequency to output laser, simultaneously starting to shoot and collect interference signals by the camera, after one period of the sweep frequency is finished, converting the signals collected by the camera to obtain a conversion spectrum, and obtaining the accurate distance of each point shot by the camera on an object by a signal peak in the conversion spectrum.
The method for measuring the distance or the thickness by adopting the distance/thickness measuring device is used for measuring a wafer with a large area and a large-size precision part, wherein the large area or the large size is a rectangle or a circle with the side length of dozens of millimeters.
Generally, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:
the area array sweep frequency distance measuring/thickness measuring system is added with the active optical anti-shake system, so that the thickness and the distance of an object can be measured greatly, accurately and quickly, and optical anti-shake can be realized. For the shape measurement of the part, an area array camera is utilized to acquire interference signals in a large format, point scanning is not required to be performed by mechanical motion in the measurement process, the measurement speed is not limited by the mechanical scanning speed, and the measurement speed is determined by the frequency sweeping speed of a frequency sweeping light source and the acquisition speed of the camera, so that the measurement speed is higher. The first lens in the device is arranged at a sample to be measured, has the functions of illuminating and amplifying an imaging area, and is suitable for measuring large-area wafers and large-size precision parts, such as microwave filters with side lengths of dozens of millimeters and other products. The amplification type measuring system can realize object morphology measurement in a large area range at one time, does not need to take pictures and splice for multiple times, and has the advantages of simple device, stable structure and fast data processing. Compared with the method for removing the speckles by adopting a dynamic method, the method for removing the speckles by adopting a static method can ensure that the running speed of the system is not influenced by the method for removing the speckles. The active optical anti-shake system can acquire the vibration of the environment in real time and perform corresponding compensation, so that the measurement error is reduced, and the measurement precision can be greatly improved.
Drawings
Fig. 1 is a schematic diagram of an enlarged area array swept range finding/thickness measuring system with active optical anti-shake function according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Fig. 1 is a schematic diagram of an enlarged area array frequency-sweeping distance measuring/thickness measuring system with an active optical anti-shake function according to an embodiment of the present invention, and it can be seen that an area array frequency-sweeping distance measuring/thickness measuring device with an active optical anti-shake function according to the present invention includes an enlarged area array frequency-sweeping distance measuring subsystem and an active optical anti-shake subsystem.
The amplification type area array frequency scanning and ranging subsystem comprises a tunable laser 1, a first collimator 2, a beam expander 3, a beam splitter 5, a first lens 9, a second lens 14 and a camera 17. The first lens 9 is an enlargement type lens, and the second lens 14 is a telecentric lens. Tunable laser 1 is connected to first collimator 2 through optic fibre, and first collimator 2 is the optic fibre collimator for the divergent light collimation that the optic fibre was exported becomes parallel light, and 3 is the beam expander, is used for expanding the light beam to the facula that typical value is 30mm, and 4 is first dichroic mirror, and the characteristics are to the light of certain wavelength almost totally passing through, and to the light of other wavelength almost totally reflection. Reference numeral 5 denotes a beam splitter having four ports at the first, second, third and fourth ports, respectively, and four ports at the four sides of the rectangle, respectively, and light is input from the first port of the beam splitter 5 and output from the second and third ports. The light energy enters the beam splitter 5 directly through the first dichroic mirror 4. The parallel light output from the second port is incident on the object to be measured 10 after passing through the first lens 9, and after being reflected by the object to be measured 10, the light rays pass back through the beam splitter 5 to enter the second dichroic mirror 6, and then sequentially pass through the second lens 14 to irradiate on the camera 17. Wherein, adjustable apertures can be arranged in the first lens 9 and the second lens 14, and the speckle phenomenon occurring on the camera 17 can be improved by adjusting the apertures to a proper size. The parallel light output from the third port of the beam splitter 5 is incident on the filter 11. The filter 11 is a neutral filter for attenuating the light intensity. Adjacent to the filter 11 a movable reflective element 15 is arranged, the movement of which is controlled by an acquisition control unit 18. The light is reflected by the movable reflecting element 15, and the original path passes through the third port of the beam splitter, is output from the fourth port of the beam splitter, enters the second dichroic mirror 6, and is irradiated onto the camera 17 through the second dichroic mirror 6 and the second lens 14.
In the practical engineering, the distance between the sensor of the camera 17 and the first lens 9 is, for example, 200mm, and the back intercept of a general lens is usually small, so that in the practical imaging, light reflected by the sample to be measured 10 may be actually imaged in the beam splitter 5 or the second dichroic mirror 6 through the first lens 9 and cannot be directly imaged onto the sensor of the camera 17. The real image can be relayed onto the image plane of the camera 17 using the second lens 14. The distance between the first lens 9 and the second lens 14 is preferably 100 mm. In addition, the second lens 14 can further change the magnification of the optical system, and the optical magnification of the system is the product of the optical magnification of the first lens 9 and the optical magnification of the second lens 14. The lens 14 is not necessary when the back intercept of the first lens 9 is long enough to project an image directly onto the camera's sensor and the image formed by the lens 9 can be fully received by the camera.
The active optical anti-shake subsystem comprises a broad spectrum light source 8, a second collimator 7, a third collimator 12, a first dichroic mirror 4, a beam splitter 5, a spectrometer 13 and a piezoelectric ceramic displacement table (PZT). The broad spectrum light source 8 is connected to the second collimator 7 through an optical fiber, and the second collimator 7 is an optical fiber collimator and is reflected by the first dichroic mirror 4 to enter the beam splitter 5. Light is input from the first port of the beam splitter 5 and output from the second and third ports. Parallel light output from the second port of the beam splitter 5 is incident on an object to be measured 10 through the first lens 9, reflected by the object, and output from the fourth port of the beam splitter 5 after passing through the second port of the beam splitter 5 in a primary path, and then sequentially incident on the spectrometer 13 through the second dichroic mirror 6 and the third collimator 12. The parallel light output from the third port of the beam splitter 5 is incident on the filter 11. 15 are movable reflective elements whose movement is controlled by an acquisition control unit 18. The light is reflected by the movable reflective element 15, passes through the third port of the beam splitter on the original path, is output from the fourth port of the beam splitter 5, and then is incident on the spectrometer 13 through the second dichroic mirror 6 and the third collimator 12.
The process of the time-varying wavelength output by the tunable laser 1 is called optical frequency scanning, frequency sweeping for short. The tunable laser 1 may also be implemented to emit trigger signals at equal wave number intervals, i.e. to emit a trigger signal to control the camera 17 to start the acquisition whenever the wave number of the output light changes by the same wave number. The acquisition control unit 18 has functions of acquiring signals of the camera and the spectrometer and displaying data, and can control devices such as the laser and the camera through electric signals.
In the active optical anti-shake system of the present invention, the typical wavelength of the broad spectrum light source is 1525-. The SLD light source, the common LED light source, the femtosecond laser and other wide spectrum light sources can realize the optical anti-shake function. The wavelength of the broad-spectrum light source is different from that of the tunable laser, and the beam is converged or split by the dichroic mirror with extremely low loss in the optical path.
The back reflection of each optical element in the first lens 9 forms interference fringes, which interfere with imaging. The solution to overcome this problem is: and the exposure time is increased while the frequency is swept, so that the retrogression of the retroreflection light from the first lens 9 and the light degradation from the sample 10 to be measured are enabled to be incoherent superposition or a low coherence frequency sweeping light source is used instead. Meanwhile, the reflectivity of the sample to be detected should be as high as possible, so that the image contrast is ensured.
The area array sweep frequency ranging system adopts a camera as a detector, collects interference light intensity information under different frequencies, and can simultaneously perform frequency analysis on interference signals between two paths of light in a conversion spectrum through a signal conversion means, particularly a signal processing method such as Fourier conversion and the like, so as to convert the interference signals into distance. The active optical anti-shake system is realized on the basis of the optical path of the area array frequency sweep ranging system, the utilization rate of an optical device can be improved, and the complexity of the system is reduced. The active optical anti-shake system can obtain the vibration of the environment through data processing such as Fourier transform according to the data of the spectrometer, further drive PZT displacement, drive the movable reflection element to move, can compensate the environmental vibration, and realize the optical anti-shake function.
In the invention, in the area array sweep frequency ranging/thickness measuring system, the area array measuring method is adopted, and the camera is used for collecting interference data, thereby breaking through the limitation of point detection. The whole device can realize large-breadth, high-precision and quick measurement of the object. The active optical anti-shake system added can compensate the vibration of the environment, reduce the measurement error and realize the optical anti-shake function.
In the invention, an amplifying type lens is added, and the function of amplifying an imaging area is achieved. The distance measuring or thickness measuring device with the amplifying function is suitable for measuring wafers with large areas and precision parts with large sizes, such as microwave filters with side lengths of dozens of millimeters and the like. The amplification type measuring system can realize object morphology measurement in a large area range at one time, does not need to take pictures and splice for multiple times, and has the advantages of simple device, stable structure and fast data processing. The preferred lens is a telecentric lens with an aperture, and the speckle can be inhibited by adjusting the aperture without influencing the photographing speed.
In the invention, the area array frequency sweep is adopted, mechanical scanning is not needed, vibration caused by mechanical scanning is naturally overcome, high-precision large-breadth measurement is easier to realize, the breadth of hundreds of millimeters square can be achieved even, the measurement time is faster, and the requirement on devices is very low. For example, if a 3000-point-by-3000-point format is also measured, the measurement rate of the second generation point-scan OCT technique is 10 ten thousand points/second, then he measures 90s, while for the third generation, it can be completed in 2s without the limitation of frequency sweep. The essence is that light is irradiated on an object, and the light reflected from the object to a light detector is analyzed by an area-array camera, so as to obtain the height information of a point, and each pixel of the area-array camera can be regarded as a light detector corresponding to a small measured light spot on the object.
Each generation of OCT techniques suffers from the problem that they use fourier transform (FFT) algorithms that waste half of the range because the FFT produces signals that are one-to-one identical, i.e., mirrored, on the positive and negative half-axes. The use of dispersion coding can make the two signals which are originally identical in a mode different from each other, thereby expanding the range by one time. The use of dual reference arms provides the possibility of further range up. In the third generation area array OCT, there are various optical path structures. However, one problem is that due to the surface illumination, the reflected light from each point on the object to be measured may be reflected by diffuse reflection to a plurality of pixels or even the whole camera, and due to the high coherence of the monochromatic light source, the crosstalk light interferes, and a large number of light spots with alternating light and dark spots, called speckles, are formed on the camera. The speckle causes the over-weak and over-strong of partial signals, and carries the distance information of other points, which affects the work of the measuring system. Therefore, measures are needed to remove the speckles, and compared with a dynamic method, a static method is adopted to remove the speckles, so that the operation speed of the system is not influenced by the method for removing the speckles.
Ranging applications refer to: the known object to be measured has an opaque surface and only the distance of the surface from the reference surface needs to be measured.
The thickness measurement application refers to: the object to be measured has certain transparency and has two or more obvious layered interfaces, and the distance between the two layers is measured, namely the thickness measuring application.
When the thickness measuring application is carried out, the system has the problem of dead zones. In theory, a scheme of double reference arms and a dispersion coding method can be used, but the scheme causes mutual interference of a plurality of signals and is not practical. The tilt reference mirror method can be used to remove the dead zone of measurement and expand the range to 2 NMR. The dead zone can be removed and the range expanded to 2NMR using a phase shift method that moves the reference arm.
The specific application scenarios of distance measurement and thickness measurement are as follows: for chip thickness measurement and measurement of glass appearance characteristics, the measurement and ranging method mainly focuses on measurement of measuring ranges from dozens of millimeters to dozens of micrometers in the height direction.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (10)
1. The device for range finding/thickness measurement of the amplified area array with the active optical anti-shake function is characterized by comprising a first dichroic mirror (4), a beam splitter (5), a second dichroic mirror (6), a lens (9), a camera (17), a spectrometer (13), an acquisition control unit (18) and a movable reflecting device (15),
a beam splitter (5) is arranged in the transmission light direction of the first dichroic mirror (4), an objective table is arranged in the reflection light direction of the beam splitter (5) and used for placing a sample to be measured for distance or thickness, a lens (9) is arranged between the objective table and the beam splitter (5), a movable reflection device (15) is arranged in the transmission light direction of the beam splitter (5),
the beam splitter (5) is provided with four ports which are respectively positioned on four edges of a rectangle, a first port and a third port are positioned on two opposite edges, the first port is over against the first dichroic mirror (4), the second port is over against the lens, the third port is over against the movable reflecting device (15), a second dichroic mirror (6) is arranged in the direction of the fourth port,
set up camera (17) on second dichroic mirror (6) transmission light direction, camera (17) link to each other with collection control unit (18), set up spectrum appearance (13) on second dichroic mirror (6) reverberation direction, spectrum appearance (13) intercommunication collection control unit (18), collection control unit (18) have the function of the signal of gathering camera and spectrum appearance and display data.
2. An amplified planar array swept range finding/thickness measuring device with active optical anti-shake function as claimed in claim 1, wherein in operation, parallel light for implementing planar array sweep for distance measurement or thickness measurement is further disposed in the transmission light direction of the first dichroic mirror (4), the parallel light and the beam splitter (5) are respectively disposed on both sides of the first dichroic mirror (4), parallel light for implementing optical anti-shake is disposed in the reflection light direction of the first dichroic mirror (4), and the parallel light and the beam splitter (5) for implementing optical anti-shake are respectively disposed in two mutually perpendicular reflection light directions of the first dichroic mirror (4).
3. An amplified area array swept range finding/thickening apparatus with active optical anti-shake capability as claimed in claim 2, further comprising a tunable laser (1), a first collimator (2), a beam expander (3), a broad spectrum light source (8) and a second collimator (7), wherein,
a first collimator (2) and a beam expander (3) are sequentially arranged in the emergent light direction of the tunable laser (1), the beam expander (3) is just opposite to one side of the first dichroic mirror (4), the beam expander (3) and the beam splitter (5) are respectively positioned at two sides of the first dichroic mirror (4),
a second collimator (7) is arranged in the emergent light direction of the broad spectrum light source (8), and the second collimator (7) and the beam splitter (5) are respectively positioned in the two mutually perpendicular reflected light directions of the first dichroic mirror (4).
4. An amplified area array swept range finding/thickening apparatus with active optical anti-shake capability, according to claim 3, further comprising a third collimator (12), the third collimator (11) being located between the second dichroic mirror (6) and the spectrometer (13), a filter (11) being arranged between the movable reflective device (15) and the beam splitter (5), the filter (11) being a neutral filter for attenuating the light intensity.
5. An amplified area array swept range finding/thickening apparatus with active optical anti-jitter function as claimed in claim 4 wherein the wavelength of the broad spectrum light source is 1525 nm-1575 nm or 1290 nm-1330 nm, the wavelength of the broad spectrum light source is different from the wavelength of the tunable laser, the light emitted from the broad spectrum light source and the light emitted from the tunable laser pass through the first and second dichroic mirrors in the optical path to converge or split the beams.
6. An enlarged area array sweep frequency distance measuring/thickening device with active optical anti-shake function according to claim 5, characterized in that it further comprises a lens (9), the lens (9) is an enlarged telecentric lens, when the light reflected by the sample (10) is still larger than the light-sensitive surface of the camera after passing through the lens (9), a lens (14) is arranged between the second dichroic mirror (6) and the camera (17), the lens (14) is a telecentric lens and plays a role of reducing and imaging the image formed by the lens (9) to the camera, and the distance between the first lens (9) and the second lens (14) is preferably 100 mm.
7. The device for distance measurement/thickness measurement of an amplified area array with active optical anti-shake function as claimed in claim 6, wherein the acquisition control unit (18) is electrically connected to the tunable laser (1) to control the tunable laser by an electrical signal, the beam expander (3) is used to expand the light beam to a spot of 20 mm-40 mm, both the lens (14) and the lens (9) have adjustable apertures, and the speckle phenomenon occurring on the camera (17) can be improved by adjusting the apertures to a proper size during operation.
8. An amplified area array swept ranging/thickness measurement device with active optical anti-shake function as claimed in claim 7, wherein the movable reflection device (15) is disposed on a piezo-ceramic displacement stage, the piezo-ceramic displacement stage is connected to the collection control unit (18) to move under the control of the collection control unit (18), and further the movable reflection device (15) is driven to move.
9. Method for measuring distance or thickness with a distance/thickness measuring device according to claims 3-7, characterized in that it comprises the following steps:
s1: starting the tunable laser, the broad spectrum light source, the spectrometer and the acquisition control unit to fully preheat the tunable laser, the broad spectrum light source, the spectrometer and the acquisition control unit,
s2: placing the object to be measured on an object stage, adjusting the position of the object stage to enable the light beam emitted by the tunable laser to cover the object to be measured as much as possible, adjusting the first collimator to enable the light emitted by the broad-spectrum light source to irradiate the object to be measured,
s3: the spectrum collected by the spectrometer is processed by Fourier transform data to obtain a transform spectrum, the distance of a sample to be measured is obtained by a signal peak in the transform spectrum, a plurality of distances are obtained by measuring for a plurality of times, the measured distance is changed due to optical jitter, the acquisition control unit drives the movable reflector to move according to the variation of the measured distance to compensate vibration and realize the optical anti-jitter function,
the step S3 is continuously performed during the whole process of distance measurement or thickness measurement to compensate the optical vibration in real time, realize optical anti-shake,
s4: starting the sweep tunable laser, starting to sweep frequency to output laser, simultaneously starting to shoot and collect interference signals by the camera, after one period of the sweep frequency is finished, converting the signals collected by the camera to obtain a conversion spectrum, and obtaining the accurate distance of each point shot by the camera on an object by a signal peak in the conversion spectrum.
10. The method for measuring distance or thickness using the distance/thickness measuring device according to claim 9, wherein it is used for measuring a wafer having a large area, a precision part having a large size, which is a rectangle or a circle having a side of several tens of millimeters.
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