CN112731344B - Amplified area array sweep frequency distance measurement/thickness measurement device and method with active optical anti-shake function - Google Patents
Amplified area array sweep frequency distance measurement/thickness measurement device and method with active optical anti-shake function Download PDFInfo
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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
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Abstract
The invention discloses an amplifying type area array sweep frequency distance measuring/thickness device with an active optical anti-shake function, which relates to the field of laser sweep frequency distance measuring and comprises a first dichroic mirror, a second dichroic mirror, a beam splitter, a lens, a camera, a spectrometer, an acquisition control unit and a movable reflecting device, wherein the 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, the lens is arranged between the objective table and the beam splitter, the beam splitter is provided with four ports, the first port is opposite to the first dichroic mirror, the second port is opposite to the lens, the third port is opposite to the movable reflecting device, the fourth port is opposite to the second dichroic mirror, the camera is arranged in the transmission light direction of the second dichroic mirror, the camera is connected with the acquisition control unit, the spectrometer is arranged in the reflection light direction of the second dichroic mirror, and the spectrometer is 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. 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 sweep frequency distance measurement, and particularly relates to an amplified area array sweep frequency distance measurement/thickness 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 critical for high-performance equipment, and it is very important to accurately and stably produce parts with specific required sizes and shapes. Therefore, accurate inspection of the produced parts is an important element to ensure high quality production.
In the prior art, application number 201910648603.5 discloses a patent application named as 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 to obtain the depth of an object to be measured in the Z-axis direction, and is also used for generating the three-dimensional coordinate of the object to be measured in an XY plane coordinate by combining the object to be measured reacted by a two-dimensional displacement platform, which is essentially a feature of a part obtained by point-by-point scanning, and a sample is arranged on a X, Y two-dimensional platform, so that the measuring range can be expanded, but the measuring process depends on mechanical movement, mechanical scanning errors are necessarily introduced, and the equipment faces the problems of ageing, instability and the like of moving parts. But also the measurement speed is limited by the speed of scanning, and it is difficult to obtain high measurement speed while high sensitivity, which is determined by the characteristics of the spot scanning. During the measurement, related optical elements shake due to the influence of external environment and operation process, so that the measurement result has a certain error.
OCT titled "Performance analysis of a full-field and full-range sweet-source OCT
The english paper of system "discloses an area array tomography system with swept light source and camera, microscope, sleeve lens as the core device. But it has the following disadvantages: LSR used in the system is a movable speckle attenuator, and the working principle of LSR is that the camera receives multiple optical phases within one exposure time through the vibration of the highest hundred hertz of the element, so that speckle is inhibited. Therefore, the frame rate of the camera in this mode of operation must be tens of times slower than the LSR to achieve the speckle suppression effect, and the faster the camera, the worse the suppression effect. This dynamic speckle-suppressing method severely limits the photographing speed of the camera, and thus becomes a bottleneck that the ranging system has difficulty in high-speed measurement. And the design of a microscope is adopted, so that the method is not suitable for a single distance measurement scene of a large-size object.
Therefore, there is a need to develop a large-format, high-precision, fast method of measuring object thickness and distance that does not require point scanning of the sample.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide an amplified area array sweep frequency 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 in the device and the method for measuring the thickness or the distance of several millimeters to tens of micrometers in the prior art.
In order to achieve the above object, the present invention provides an amplified area array sweep ranging/thickness apparatus with active optical anti-shake function, comprising a first dichroic mirror, a beam splitter, a second dichroic mirror, a lens, a camera, a spectrometer, an acquisition control unit and a movable reflecting device, wherein,
a beam splitter is arranged in the transmission light direction of the first dichroic mirror, a carrier is arranged in the reflection light direction of the beam splitter and used for placing a sample to be measured in distance or thickness, a lens is arranged between the carrier and the beam splitter, a movable reflecting device is arranged in the transmission light direction of the beam splitter,
the beam splitter has four ports, which 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 opposite to the first dichroic mirror, the second port is opposite to the lens, the third port is opposite to the movable reflecting 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, the camera is connected with the acquisition control unit, the spectrometer is arranged in the reflection light direction of the second dichroic mirror, the spectrometer is 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.
Furthermore, in operation, parallel light for realizing area array sweep frequency to measure distance or thickness is also arranged in the transmission light direction of the first dichroic mirror, the parallel light and the beam splitter are respectively arranged at two sides of the first dichroic mirror, parallel light for realizing optical anti-shake is arranged in the reflection light direction of the first dichroic mirror, and the parallel light for realizing optical anti-shake and the beam splitter are respectively arranged in two mutually perpendicular reflection light directions of the first dichroic mirror.
Further, the device also comprises a tunable laser, a first collimator, a beam expander, a wide 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 opposite to one side of the first dichroic mirror, the beam expander and the beam splitter are respectively positioned at two sides of the first dichroic mirror,
the second collimator and the beam splitter are respectively positioned in two mutually perpendicular reflected light directions of the first dichroic mirror.
Further, the device also comprises a third collimator, wherein the third collimator is positioned between the second dichroic mirror and the spectrometer, and a filter is arranged between the movable reflecting device and the beam splitter and is a neutral filter for attenuating light intensity.
Further, the wavelength value 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, and the light emitted by the broad spectrum light source and the light emitted by the tunable laser pass through the first dichroic mirror and the second dichroic mirror in the optical path to be converged or split.
Further, when light reflected by the sample to be detected is still larger than the light sensitive surface of the camera or light reflected by the sample to be detected cannot be directly imaged on the sensor of the camera after passing through the lens, a second lens is arranged between the second dichroic mirror and the camera, the second lens is a telecentric lens and plays a role in imaging the lens in a reduced relay imaging mode to the camera, and the distance between the lens and the second lens is preferably 100mm.
Further, the acquisition control unit is electrically connected with the tunable laser, so that the tunable laser can be controlled through an electric signal, the beam expander is used for expanding a beam to a light spot of 20-40 mm, the lens and the second lens are both provided with adjustable diaphragms, and during operation, speckle phenomenon on a camera can be improved by adjusting the diaphragms to proper sizes.
Further, the movable reflecting device is arranged on the piezoelectric ceramic displacement table, and the piezoelectric ceramic displacement table is connected with the acquisition control unit so as to move under the control of the acquisition control unit, and then the movable reflecting device is driven to move.
According to a second aspect of the present invention there is also provided a method of ranging or thickness measurement for a ranging/thickness device as described above, comprising the steps of:
s1: the tunable laser, the broad spectrum light source, the spectrometer and the acquisition control unit are started to fully preheat the laser,
s2: placing the object to be measured on the objective table, adjusting the position of the objective table 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 wide-spectrum light source to irradiate the object to be measured,
s3: carrying out Fourier transform data processing on the spectrum acquired by the spectrometer to obtain a transformed spectrum, obtaining the distance of a sample to be detected from a signal peak in the transformed spectrum, measuring for multiple times to obtain multiple distances, wherein the optical jitter causes the measured distance to change, driving a movable reflecting device to move according to the change amount of the measured distance by an acquisition control unit so as to compensate vibration, realizing the optical anti-shake function,
in the whole process of distance measurement or thickness measurement, the step S3 is continuously executed to compensate the optical vibration in real time, realize the optical anti-shake,
s4: starting a scanning tunable laser, starting scanning to output laser, starting a camera to shoot and collect interference signals, after one period of scanning 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 the object by a signal peak in the conversion spectrum.
The distance measuring or thickness measuring method using the distance measuring/thickness measuring device as described above is used for measuring and measuring a large-area wafer, a large-size precision part, which is a rectangle or a circle with a side length of several tens millimeters.
In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:
the area array sweep frequency distance measuring/thickness measuring system is added with the active optical anti-shake system, can measure the thickness and distance of an object in a large scale, with high precision and fast, and can realize optical anti-shake. For the shape measurement of the part, the area array camera can collect interference signals in a large format, mechanical movement is not needed for point scanning in the measurement process, the measurement speed is not limited by the mechanical scanning speed, and is determined by the sweep speed of the sweep frequency light source and the camera collecting speed, so that the measurement speed is higher. The lens is arranged at the sample to be measured, has the functions of lighting and amplifying an imaging area, and is suitable for measuring large-area wafers and large-size precision parts, such as products of microwave filters with side lengths of tens of millimeters. The amplifying type measuring system can realize object morphology measurement in a large area range at one time, does not need to photograph and splice for many times, and has the advantages of simple device, stable structure and quick 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, perform corresponding compensation, reduce the measurement error and greatly improve the measurement accuracy.
Drawings
FIG. 1 is a schematic diagram of an amplified area array swept ranging/thickness system with active optical anti-shake functionality in an embodiment of the invention.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Fig. 1 is a schematic diagram of an amplified area array sweep ranging/thickness system with an active optical anti-shake function according to an embodiment of the present invention, where it can be seen that an area array sweep ranging/thickness device with an active optical anti-shake function according to the present invention includes an amplified area array sweep ranging subsystem and an active optical anti-shake subsystem.
The amplification type area array sweep frequency range finding subsystem comprises a tunable laser 1, a first collimator 2, a beam expander 3, a beam splitter 5, a lens 9, a second lens 14 and a camera 17. The lens 9 is an magnifying lens, and the second lens 14 is a telecentric lens. The tunable laser 1 is connected to a first collimator 2 through an optical fiber, the first collimator 2 is an optical fiber collimator for collimating divergent light output from the optical fiber into parallel light, 3 is a beam expander for expanding a light beam to a spot with a typical value of 30mm, and 4 is a first dichroic mirror, and is characterized in that it is almost completely transparent for light with a certain wavelength and almost completely reflective for light with other wavelengths. And 5 is a beam splitter, which has four ports respectively at the first, second, third and fourth ports, and the four ports are respectively positioned at four sides of the rectangle, and light is input from the first port of the beam splitter 5 and output from the second and third ports. The light energy passes directly through the first dichroic mirror 4 into the beam splitter 5. The parallel light output from the second port is incident on the measured object 10 after passing through the lens 9, and after being reflected by the measured object 10, the light enters the second dichroic mirror 6 after passing through the beam splitter 5, and then sequentially passes through the second lens 14 and is irradiated on the camera 17. Wherein, adjustable aperture can be set in the lens 9 and the second lens 14, and speckle phenomenon occurring on the camera 17 can be improved by adjusting aperture to 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 light is returned to the third port of the beam splitter, is output from the fourth port of the beam splitter, is incident on the second dichroic mirror 6, and is irradiated onto the camera 17 through the second dichroic mirror 6 and the second lens 14.
In engineering practice, the distance between the sensor of the camera 17 and the lens 9 is 200mm, and the rear intercept of a typical lens is often small, so in actual imaging, light reflected by the sample 10 to be measured may pass through the lens 9 to be imaged in the beam splitter 5 or the second dichroic mirror 6, and cannot be imaged directly onto the sensor of the camera 17. The real image can be relayed imaged onto the image plane of the camera 17 using the second lens 14. The distance between the lens 9 and the second lens 14 is preferably 100mm. In addition, the second lens 14 may further change the magnification of the optical system, where the optical magnification of the system is the product of the optical magnification of the lens 9 and the optical magnification of the second lens 14. The second lens 14 is not necessary when the rear intercept of the lens 9 is long enough to project an image directly onto the sensor of the camera and the image made by the lens 9 can be received completely 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 by an optical fiber, the second collimator 7 being an optical fiber collimator, reflected by the first dichroic mirror 4 into the beam splitter 5. Light is input from a first port of the beam splitter 5 and output from second and third ports. The parallel light output from the second port of the beam splitter 5 is incident on the measured object 10 through the lens 9, and after being reflected by an object, the light is originally returned through the second port of the beam splitter 5, is output from the fourth port of the beam splitter 5, and is 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 reflecting element 15, the primary path passes through the third port of the beam splitter, and then is output from the fourth port of the beam splitter 5, and then is incident to the spectrometer 13 through the second dichroic mirror 6 and the third collimator 12.
The process of changing the wavelength of the output of the tunable laser 1 with time is called optical frequency sweep, simply referred to as sweep. The tunable laser 1 may also be configured to emit a trigger signal at equal wavenumber intervals, i.e. each time the wavenumber of the outputted light changes by the same wavenumber, a trigger signal is emitted to control the camera 17 to start the acquisition. The acquisition control unit 18 has a function of acquiring signals of a camera and a spectrometer and displaying data, and can control a laser, a camera, and the like by an electric signal.
In the active optical anti-shake system of the invention, the typical wavelength value of the broad spectrum light source is 1525-1575nm or 1290-1330nm. The SLD light source, the common LED light source, the femtosecond laser and other broad spectrum light sources can realize the optical anti-shake function. The wavelength of the broad spectrum light source is different from the wavelength of the tunable laser, and the beam is converged or split with extremely low loss by the dichroic mirror in the optical path.
The back reflection of each optical element in the lens 9 creates interference fringes, interfering with imaging. The solution to overcome this problem is: the exposure time is increased while the scanning is performed, so that the backward reflection light from the lens 9 and the light from the sample 10 to be detected are degenerated to be incoherent superposition or a low-coherence scanning light source is replaced. At the same time, the reflectivity of the sample to be measured should be as high as possible, so as to ensure the contrast of the image.
The area array sweep frequency ranging system adopts a camera as a detector, collects interference light intensity information under different frequencies, and utilizes a signal conversion means, wherein the signal conversion means specifically refers to a signal processing method such as Fourier conversion, and the like, and can simultaneously carry out frequency analysis on interference signals between two paths of light in one conversion spectrum so as to convert the interference signals into a distance. The active optical anti-shake system is realized on the basis of the optical path of the area array sweep frequency ranging system, so that the utilization rate of optical devices can be improved, and the complexity of the system is reduced. The active optical anti-shake system can obtain environmental vibration through data processing such as Fourier transform according to the data of the spectrometer, further drives PZT displacement, drives a movable reflection element to move, can compensate the environmental vibration, and achieves the optical anti-shake function.
In the invention, in the area array sweep frequency distance measurement/thickness system, an area array measurement method is adopted, and the interference data is acquired by using the camera, so that the limitation of point detection is broken through. The whole device can realize large-breadth, high-precision and rapid measurement of objects. The added active optical anti-shake system can compensate the vibration of the environment, reduce the measurement error and realize the optical anti-shake function.
In the invention, an amplifying lens is added, and the function of amplifying an imaging area is realized. The distance measuring or thickness measuring device with the amplifying function is suitable for measuring large-area wafers and large-size precision parts, such as microwave filters with side lengths of tens of millimeters and the like. The amplifying type measuring system can realize object morphology measurement in a large area range at one time, does not need to photograph and splice for many times, and has the advantages of simple device, stable structure and quick data processing. The preferred lens is a telecentric lens with an aperture that is adjusted to suppress speckle without affecting the speed of photographing.
In the invention, the area array sweep is adopted, mechanical scanning is not needed, vibration introduced by the mechanical scanning is naturally overcome, high-precision large-breadth measurement is easier to realize, and even the breadth of hundreds of millimeters square can be achieved, the measurement time is faster, and the requirement on devices is very low. For example, the same measurement is performed on a 3000-point by 3000-point format, the measurement rate of the second-generation point scanning OCT technique is 10 ten thousand points/second, and then the measurement time is 90s, and for the third generation, the measurement is not limited by the frequency of the sweep, and can be completed for 2 s. Essentially, the light irradiates the object, and the height information of the point is obtained by analyzing the reflection from the object to the light detector through an area array camera, wherein each pixel of the area array camera can be regarded as a light detector and corresponds to a small light spot measured on the object.
One problem with each generation of OCT techniques is that the algorithms of fourier transform (FFT) they use waste half the span, as the FFT produces a one-to-one modulo-identical signal, i.e., a mirror image, on the positive and negative half axes. The use of dispersion coding techniques can make the two otherwise identical signals no longer identical, thereby doubling the range. The use of a double reference arm may provide the possibility to further lift the range. In the third generation of area array OCT, there are various optical path structures. However, there is a problem in that, due to the planar illumination, the reflected light from each point on the object to be measured may be applied to a plurality of pixels or even the entire camera due to diffuse reflection, and due to the high coherence of the monochromatic light source, crosstalk light may interfere, so that a large number of light spots with alternate brightness and darkness, called speckles, are formed on the camera. The existence of the speckles makes part of the signals too weak and part of the signals too strong, and carries the distance information of other points, thereby affecting the work of the measurement system. Therefore, the method needs to remove the speckles, and compared with a dynamic method, the static method can prevent the operation speed of the system from being influenced by the method for removing the speckles.
Ranging applications refer to: it is known that an object to be measured has an opaque surface and that only the distance of the surface relative to a reference surface is measured.
The thickness measurement application refers to: the measured object has certain transparency, and has two or more obvious layering interfaces, and the distance between the two layering is measured, namely the thickness measurement application.
When the thickness measurement is applied, the system has the problem of dead zone. A scheme of double reference arms and dispersion coding can be used theoretically, but it is not practical to cause mutual interference of multiple signals. The measurement dead zone can be removed by using the inclined reference mirror method, and the range can be expanded to 2NMR. The dead zone can be removed and the range can be extended to 2NMR using a phase shift method that moves the reference arm.
Specific application scenarios of ranging and thickness measurement are as follows: for chip thickness measurement, for measurement of glass morphology features, the measurement and ranging of the invention is mainly focused on measurement in the range of tens of millimeters to tens of micrometers in the height direction.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (10)
1. The amplified area array sweep frequency distance measurement/thickness device 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), wherein,
a beam splitter (5) is arranged in the transmission light direction of the first dichroic mirror (4), a carrier is arranged in the reflection light direction of the beam splitter (5) and is used for placing a sample to be measured in distance or thickness, a lens (9) is arranged between the carrier and the beam splitter (5), a movable reflecting 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 sides of the rectangle, the first port and the third port are positioned on two opposite sides, the first port is opposite to the first dichroic mirror (4), the second port is opposite to the lens, the third port is opposite to the movable reflecting device (15), the second dichroic mirror (6) is arranged in the direction of the fourth port,
the second dichroic mirror (6) is provided with a camera (17) in the transmission light direction, the camera (17) is connected with the acquisition control unit (18), the second dichroic mirror (6) is provided with a spectrometer (13) in the reflection light direction, the spectrometer (13) is communicated with the acquisition control unit (18), and the acquisition control unit (18) has the functions of acquiring signals of the camera and the spectrometer and displaying data.
2. An amplified area array sweep ranging/thickness measuring device with active optical anti-shake function as claimed in claim 1, characterized in that, in operation, parallel light for realizing area array sweep ranging or thickness measuring is further arranged in the transmission light direction of the first dichroic mirror (4), the parallel light and the beam splitter (5) are respectively arranged at two sides of the first dichroic mirror (4), parallel light for realizing optical anti-shake is arranged in the reflection light direction of the first dichroic mirror (4), and the parallel light for realizing optical anti-shake and the beam splitter (5) are respectively arranged at two mutually perpendicular reflection light directions of the first dichroic mirror (4).
3. An amplified area-array swept ranging/thickness apparatus with active optical anti-shake function according to 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 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 two mutually perpendicular reflected light directions of the first dichroic mirror (4).
4. A amplified area array swept ranging/thickness apparatus with active optical anti-shake features as claimed in claim 3, further comprising a third collimator (12), the third collimator (12) being located between the second dichroic mirror (6) and the spectrometer (13), a filter (11) being provided between the movable reflecting device (15) and the beam splitter (5), the filter (11) being a neutral filter for attenuating the light intensity.
5. The amplified area array sweep ranging/thickness apparatus with active optical anti-shake feature according to claim 4, wherein the wavelength value of the broad spectrum light source is 1525nm to 1575nm or 1290nm to 1330nm, the wavelength of the broad spectrum light source is different from the wavelength of the tunable laser, and the light emitted by the broad spectrum light source and the light emitted by the tunable laser pass through the first and second dichroic mirrors in the optical path to converge or diverge.
6. An amplified area array sweep ranging/thickness apparatus with active optical anti-shake function as claimed in claim 5, characterized in that the lens (9) is an amplified telecentric lens, and when the light reflected by the sample (10) to be measured is still larger than the photosurface of the camera after passing through the lens (9), a second lens (14) is arranged between the second dichroic mirror (6) and the camera (17), and the second lens (14) is a telecentric lens, which plays a role of reducing the image formed by the lens (9) to the camera.
7. An amplified area array sweep ranging/thickness apparatus with active optical anti-shake function as claimed in claim 6, characterized in that the acquisition control unit (18) is electrically connected with the tunable laser (1) to control the tunable laser by means of an electrical signal, the beam expander (3) is used for expanding the beam to a light spot of 20 mm-40 mm, the second lens (14) and the lens (9) are both provided with adjustable optical rings, and in operation, the speckle phenomenon occurring on the camera (17) can be improved by adjusting the optical rings to a suitable size.
8. An amplified area array sweep ranging/thickness apparatus with active optical anti-shake function as claimed in claim 7, wherein the movable reflecting device (15) is arranged on a piezoelectric ceramic displacement table, and the piezoelectric ceramic displacement table is connected with the acquisition control unit (18) so as to move under the control of the acquisition control unit (18), thereby driving the movable reflecting device (15) to move.
9. A method of ranging or thickness measurement using a ranging/thickness device according to any of claims 3-7, comprising the steps of:
s1: the tunable laser, the broad spectrum light source, the spectrometer and the acquisition control unit are started to fully preheat the laser,
s2: placing the object to be measured on the objective table, adjusting the position of the objective table 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 wide-spectrum light source to irradiate the object to be measured,
s3: carrying out Fourier transform data processing on the spectrum acquired by the spectrometer to obtain a transformed spectrum, obtaining the distance of a sample to be detected from a signal peak in the transformed spectrum, measuring for multiple times to obtain multiple distances, wherein the optical jitter causes the measured distance to change, driving a movable reflecting device to move according to the change amount of the measured distance by an acquisition control unit so as to compensate vibration, realizing the optical anti-shake function,
in the whole process of distance measurement or thickness measurement, the step S3 is continuously executed to compensate the optical vibration in real time, realize the optical anti-shake,
s4: starting a scanning tunable laser, starting scanning to output laser, starting a camera to shoot and collect interference signals, after one period of scanning 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 the object by a signal peak in the conversion spectrum.
10. A method of measuring distance or thickness using a distance/thickness measuring device according to claim 9, for measuring large area wafers, large size precision parts, said large area or large size being rectangular or circular with a side length of tens of millimeters.
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