CN115127676B - Line spectrum confocal system - Google Patents
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- CN115127676B CN115127676B CN202211051719.9A CN202211051719A CN115127676B CN 115127676 B CN115127676 B CN 115127676B CN 202211051719 A CN202211051719 A CN 202211051719A CN 115127676 B CN115127676 B CN 115127676B
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- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
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Abstract
The invention relates to a line spectrum confocal system, wherein a hole module comprises a hole plate with at least one pinhole, the pinhole is used for transmitting light, the line spectrum confocal system also comprises a motion mechanism, the motion mechanism drives the hole plate to reciprocate along the line length direction of a line light source within the irradiation range of the line light source, and the motion mechanism comprises a control module for controlling the speed of the hole plate, so that the speed and the maximum moving distance of the hole plate meet the resolution requirement of the system in the line length direction. The invention solves the problem of mutual influence of light beams of adjacent pinholes by reducing the number of the pinholes, simultaneously drives the pore plates through the motion mechanism to enable the pinholes to form a pinhole array on the time dimension, and then controls the moving speed of the pore plates to obtain the required system linear length direction resolution. The technical scheme of the invention can automatically control the linear long-direction resolution of the system so as to meet the use requirement, and the problem that adjacent pinholes influence each other in various use scenes is solved.
Description
Technical Field
The invention relates to the field of optics, in particular to a line spectrum confocal system.
Background
In the field of precise microstructure manufacturing processes, such as the IC industry, semiconductor industry, LCD industry, electromechanical automation industry, and photoelectric measurement industry, the three-dimensional profile measurement process is an important process for ensuring uniform quality of the manufacturing process. In the detection technology, because the optical or photoelectric combined method has the characteristics of high accuracy, non-contact and the like, the optical method is commonly used for detecting the tiny outline, thickness or size of an object at present. Many optical non-contact measurement techniques are widely used, including confocal measurement technique (confocal), phase shift interferometry (phase shifting interferometry), and white-light interference vertical scanning interferometry (white-light-scanning interferometry), and different measurement techniques are suitable for different measurement conditions and different fields.
The confocal measurement technology, namely the spectrum confocal technology, is an optical detection method based on the axial chromatic aberration and the color coding technology, and the position information is obtained by utilizing a spectrometer to decode the spectrum information through establishing the corresponding relation between the distance and the wavelength through the optical dispersion distance.
The existing line spectrum confocal technology generally has two types, one adopts a coaxial light path, and the other adopts a biaxial light path. The line confocal spectrometer adopting the coaxial optical path can be applied to scenes such as deep hole measurement and the like which cannot be measured by adopting a double-shaft optical path, and has more advantages. The line confocal spectrometer comprises a spatial filter element, such as a slit structure, an optical fiber array or a pinhole array structure, for example, a line spectrum confocal sensor system disclosed in chinese patent 202110732234.5, in which an optical fiber array is adopted. In the existing products, 512 pixels are achieved in the linear length direction by adopting a fiber array mode, but the resolution is far smaller than that of a main sensor. Meanwhile, the optical fiber array is formed by arranging and combining a plurality of optical fibers, the more the number of the optical fibers in a single array is, the more the probability of the optical fibers having defects is, and the high requirement on the manufacturing process of the optical fiber array is caused.
If a pinhole array is adopted for spatial filtering, in order to avoid the mutual influence of light beams of adjacent pinholes, a certain interval is needed between the adjacent pinholes, so that the resolution ratio in the linear long direction cannot be very high, in addition, the imaging quality of the general lens outside the shaft can be lower than that of the center, the size of a light spot is larger than that of the light spot at the center, which means that the pinhole far away from the center needs larger hole spacing, so as to avoid the influence between the adjacent holes, thereby not only further hindering the improvement of the resolution ratio in the linear long direction of the sensor adopting the pinhole array mode, but also providing higher requirements for the lens design.
Disclosure of Invention
The technical problem to be solved by the present invention is to overcome the defects in the prior art, and thus to provide a line spectrum confocal system.
In order to achieve the purpose, the invention adopts the following technical scheme:
a line-spectrum confocal system, comprising:
the linear light source module is used for providing a linear light source;
the relay lens group is positioned on one side of the linear light source module along the light path;
the spectroscope is positioned on one side of the relay lens group along the light path;
the hole module is positioned on one side of the spectroscope along the light path and comprises a hole plate with at least one pinhole, and the pinhole is used for transmitting light;
the dispersion objective lens is positioned between the hole module and the surface of the object to be measured; and a detection component;
the relay lens group images the line light source to the hole module, part of light rays passing through the dispersive objective lens are projected to a measured object surface, and part of light rays reflected by the measured object surface return to pass through the hole module and are collected by the detection assembly through the spectroscope; wherein, the first and the second end of the pipe are connected with each other,
the hole module further comprises a moving mechanism, the moving mechanism drives the hole plate to reciprocate along the linear length direction of the linear light source within the irradiation range of the linear light source, and the moving mechanism comprises a control module for controlling the speed of the hole plate, so that the speed and the maximum moving distance of the hole plate meet the requirement of the resolution ratio in the linear length direction of the system.
Preferably, the orifice plate has only one pinhole.
Preferably, the moving speed of the orifice plate V = fd/m,
wherein, f is the acquisition frequency of the detection assembly, d is the maximum moving distance of the pore plate, and m is the number of measurement acquisition points in the line length direction.
Preferably, a column of scanning time t of the measured object surface along the linear length direction of the linear light source is t = m/f.
Preferably, the orifice plate is provided with n pinholes along the linear length direction of the linear light source, n is more than or equal to 2, and the maximum moving distance d of the orifice plate is equal to the distance d5 between the adjacent pinholes.
Preferably, the distance d5 between adjacent pinholes is in relation to the diameter d3 of the pinholes, d5 > 10d3.
Preferably, the moving speed V' = ndf/m of the orifice plate, where f is the collection frequency of the detection assembly, and m is the number of measurement collection points in the line length direction;
and scanning time t' = m/nf of the measured object surface along a line length direction of the line light source.
Preferably, the aperture plate moves a unit moving distance Δ d1 along the line length direction of the line light source, the moving unit measuring distance Δ d2, Δ d2= k Δ d1 of the light spot irradiated on the measured surface, and k is the magnification of the dispersion objective lens.
Preferably, the diameter d3 of the pinhole, the diameter d4 of the light spot irradiated on the measured object surface, d4 > kd3, k is the magnification of the dispersive objective lens, and the unit measuring distance Δ d2 is smaller than the diameter d4 of the light spot.
Preferably, the line light source emitted by the line light source module is a wide-spectrum line light source, and the ratio of the line length to the line width is greater than 10; the spectral range of the linear light source is more than 100nm;
the relay lens group is also used for amplifying the linear light source to enable the line width of the linear light source to be larger than the diameter of the pinhole;
the spectroscope is used for separating an illumination light path and a spectrometer light path, and the splitting ratio of the spectroscope is 50;
the aperture plate comprises a surface with light absorption, the cross section of the pinhole is trapezoidal, the small end part of the pinhole faces the dispersive objective lens, and the large end part of the pinhole faces the spectroscope; the surface of the pore plate is provided with a light absorption groove;
the detection assembly comprises an achromatic astigmatic objective lens, a dispersive device, an achromatic focusing objective lens and an image acquisition unit.
Compared with the prior art, the invention has the beneficial effects that:
the confocal system of line spectrum that provides among the above-mentioned technical scheme through reducing pinhole quantity, increases the pinhole interval, solves the problem of the light beam mutual influence of adjacent pinhole, simultaneously, drives the orifice plate through the motion mechanism, makes the pinhole form the pinhole array in the time dimension, controls the translation rate of orifice plate again, obtains the long direction resolution ratio of system line of wanting. The technical scheme of the invention can automatically control the on-line long-direction resolution of the system so as to meet the use requirement, and the problem that adjacent pinholes are mutually influenced is solved in various use scenes.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic view of a line spectrum confocal system according to a first embodiment of the invention.
FIG. 2 is a schematic view of the movement of the orifice plate shown in FIG. 1.
FIG. 3 is a schematic view of the linear light source irradiating the surface of the object to be measured while the aperture plate shown in FIG. 1 is moving.
Fig. 4 is a schematic structural diagram of an orifice plate according to an embodiment of the present invention.
Fig. 5 is another schematic structural diagram of an orifice plate according to an embodiment of the present invention.
Fig. 6 is a schematic moving diagram of an orifice plate according to a second embodiment of the present invention.
Fig. 7 is an imaging schematic diagram of a line spectral confocal system in a detection assembly according to an embodiment of the present invention.
Description of reference numerals:
1. a line light source module; 2. a relay lens group; 3. a beam splitter; 31. an illumination light path; 32. a spectrometer optical path; 4. a hole module; 41. a motion mechanism; 42. an orifice plate; 421. a pinhole; 422. a light absorbing groove; 43. an irradiation range; 5. a detection component; 51. an achromatic objective lens; 52. a dispersive device; 53. an achromatic focusing objective lens; 54. a camera; 6. the surface of the object to be measured; 61. light spots; 7. a dispersive objective lens.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
As shown in fig. 1, the embodiment of the present invention provides a line spectrum confocal system, which includes a line light source module 1 for providing a line light source; the relay lens group is positioned on one side of the linear light source module 1 along the light path and is an imaging component; a spectroscope 3 positioned at one side of the relay lens group along the light path; the hole module 4 is positioned on one side of the spectroscope 3 along the light path and comprises a hole plate 42 with at least one pinhole 421, and the pinhole 421 is used for transmitting light; the dispersive objective lens 7 is positioned between the hole module 4 and the object surface 6 to be measured; and a detection assembly 5.
The line light source module 1 can provide a line light source, and there are many ways to generate the line light source in the common technology, such as forming the line light source by using a light source unit and a lens set, and the line light source is a broad spectrum line light source with different wavelengths. For convenience of description, the linear length direction of the linear light source is the Y direction, the line width direction is the X direction, and the direction perpendicular to the Y axis and the X axis is the Z direction, i.e., the height direction, since the linear spectrum confocal system of the present invention generally scans in the Y direction during scanning, if the object to be measured moves along the X direction (line width direction), the linear spectrum confocal system of the present invention can obtain the height information of the whole object surface 6 to be measured.
As shown in fig. 1, after passing through the relay lens group, the line light source passes through the spectroscope 3 and is imaged to the aperture module 4, only the pinhole 421 of the aperture module 4 can transmit light, after passing through the line light source of the pinhole 421, the light of different wavelengths is imaged to different heights by the dispersion objective lens 7, in fig. 1, focusing positions of different heights of the light of three wavelengths are listed, which are respectively marked as λ 1, λ 2, and λ 3 from top to bottom, part of the light reflected by the object surface 6 to be measured passes through the dispersion objective lens 7 and is re-converged to the aperture device, while only the light of the wavelength focused on the object can mostly pass through the pinhole 421, most of the light of the rest wavelengths is blocked outside the pinhole 421, and the light passing through the pinhole 421 passes through the spectroscope 3 and is collected by the detection assembly 5, the detection assembly 5 includes a lens group which forms the light of different wavelengths into different directions, then the light of different colors is focused and imaged on the image collecting unit of the detection assembly 5, the image collecting unit may be a camera 54, the light of different colors of the light on the light modulating surface 6 is imaged to obtain the information shown in fig. 7, which is shown in fig. 1. Based on this, the wavelengths of different focal heights are different and correspond to the height information of the measured object surface 6, therefore, the detection assembly 5 needs to encode the height information of the measured object surface 6 by using different wavelengths, the height information of the measured object surface 6 can be obtained only by detecting the wavelength information acquired by the detection assembly 5, the spectral range of the line light source is greater than 100nm, and enough light rays with different wavelengths are obtained, so that the line spectral confocal system of the present invention has sufficient resolution in the Z direction, and preferably, the spectrum of the line light source can be any one of 400 to 1000nm.
In order to make as little light as possible irradiate outside the effective area, thereby generating stray light, the ratio of the line length to the line width of the line light source is greater than 10.
The relay lens group 2 is also used for magnifying a line light source, so that the line width of the line light source is larger than the diameter of the pinhole 421, and preferably, the magnification k of the relay lens group 2 may be 0.1 to 10.
The spectroscope 3 is used for separating the illumination light path 31 from the spectrometer light path 32, and the splitting ratio is 50; illumination path 31 is along the Z direction and spectrometer path 32 is the path from beamsplitter 3 to detection assembly 5. The spectroscope 3 may be a spectroscope prism or a plate glass plated with a spectroscopic film.
The dispersion objective lens 7 is used for imaging light with different wavelengths penetrating through the pinhole 421 at different heights, and imaging light reflected by the measured object surface 6 to the pinhole 421, the dispersion objective lens 7 corrects aberration at a large field of view to be close to a central field of view, and in order to ensure the consistency of measurement accuracy in the whole measurement range, the effective light spot size at the large field of view should not be larger than 3 times of that of a middle field of view.
As shown in fig. 1, the detection assembly 5 includes an achromatic collimator objective 51, a dispersive device 52, an achromatic focusing objective 53, and an image collecting unit, where the achromatic collimator objective 51 is used to collimate light emitted from the pinhole 421 and entering the spectrometer optical path 32, the dispersive device 52 is used to modulate light with different wavelengths into collimated light with different propagation directions, and the dispersive device 52 may be a dispersive prism, a transmission grating, or a reflection grating. If the dispersive device 52 is a grating, the 1 st order diffracted light is preferred to be more efficient. The achromatic focusing objective 53 is used to focus the light of different wavelengths emitted from the dispersive device 52 to different positions in the Z direction of the image capturing unit. The optical axis of the achromatic focusing objective 53 should be parallel to the main wavelength beam propagation direction of the light source, and if the spectral range is 400 to 700nm, the main wavelength should be 550nm. The image acquisition unit may be a camera 54, preferably an area-array camera 54, and may be a CCD camera 54 or a CMOS camera 54.
The aperture module 4 further includes a moving mechanism 41, the moving mechanism 41 drives the aperture plate 42 to reciprocate along the line length direction of the line light source within the irradiation range of the line light source, i.e. reciprocate along the Y direction shown in fig. 3, and ensures that the pinhole 421 always moves within the irradiation range 43 of the line light source during the movement, and as shown in fig. 2, the pinhole 421 moves from the initial point a to B and always moves within the irradiation range 43 of the line light source.
Preferably, in order to avoid the light irradiated to the aperture module 4 from being reflected into the spectrometer optical path 32 and collected by the detection assembly 5, the aperture module 4 should be blackened, that is, the aperture plate 42 and the moving mechanism 41 should be blackened, the moving mechanism 41 may be a stepping motor, a servo motor, a piezoelectric inertial displacer or other conventional driving devices, and the surface of the moving mechanism 41 is blackened. For the orifice plate 42, the orifice plate 42 having a light-absorbing surface may be used in this embodiment, specifically, the orifice plate 42 may be a metal structure with relatively good heat conductivity, such as copper, and the surface is blackened, or the plate glass is plated with a light-absorbing material, and the light-absorbing material may be attached to the surface of the plate glass by a screen printing process or other film coating processes.
Preferably, the surface of the orifice plate 42 has light absorbing grooves 422; the light absorbing grooves 422 are disposed around the pinhole 421 and uniformly distributed in the non-light-transmitting region of the aperture plate 42 to further reduce the influence of stray light, and the inner surfaces of the light absorbing grooves 422 are blackened or provided with a light absorbing material layer, as shown in fig. 5, light irradiated onto the aperture plate 42 is reflected in the light absorbing grooves 422 and is substantially absorbed after contacting the light absorbing surface for more than 3 times, and the reflected light on the aperture plate 42 is effectively suppressed.
In order to provide structural strength to the pinhole 421, the cross section of the pinhole 421 is a trapezoid, the small end of which faces the dispersive objective lens 7, and the large end of which faces the beam splitter 3, as shown in fig. 4, where α is the side-tilt angle of the trapezoid, and the side-tilt angle α should satisfy 90- α greater than the maximum angle of the incident light. In order to ensure the structural strength and stability of the orifice plate 42, the thickness H of the orifice plate 42 should be greater than 1mm.
The movement mechanism 41 comprises a control module for controlling the speed of the orifice plate 42, so that the speed and the maximum moving distance of the orifice plate 42 meet the resolution requirement of the linear length direction of the system. In addition, the line light source magnified by the relay lens group 2 should cover the moving range of the orifice plate 42 at the line length of the orifice module 4 so that at least part of the light can pass through the pinhole 421. The embodiment of the invention solves the problem of mutual influence of light beams of adjacent pinholes by reducing the number of the pinholes and increasing the distance between the pinholes, and simultaneously drives the pore plates through the motion mechanism to form pinhole arrays on the time dimension of the pinholes and then controls the moving speed of the pore plates to obtain the required system linear length direction resolution. The technical scheme of the invention can automatically control the linear long-direction resolution of the system so as to meet the use requirement, and the problem that adjacent pinholes influence each other in various use scenes is solved. The on-line long direction resolution of the system refers to the number of measurement acquisition points in the line length direction, namely the measurement length in the line length direction is divided by the unit measurement distance in the line length direction.
The present invention has various embodiments based on the different number of pinholes 421 on the orifice plate 42.
Example one
As shown in the attached FIGS. 1 to 3, the aperture plate 42 has only one pinhole 421, when the moving mechanism 41 drives the aperture plate 42 to move a unit moving distance d1 in the Y direction, the pinhole 421 moves from the initial point A to the position B, the corresponding spot 61 irradiated on the object moves from A 'to B' by a unit measuring distance d2, i.e. the measuring distance, the relationship between Δ d1 and Δ d2 is determined by the magnification k of the dispersion objective lens 7, Δ d2= k Δ d1, the diameter d3 of the pinhole 421, the diameter d4 of the spot 61 irradiated on the object surface 6, the relationship between d3 and d4 is also related to the magnification k of the dispersion objective lens 7, and d4 > kd3. Preferably, the embodiment of the invention can set the unit measuring distance Δ d2 smaller than the diameter d4 of the light spot, so that the resolution in the wire length direction is higher, which cannot be realized by the fiber array scheme, and of course, in other embodiments, the unit measuring distance Δ d2 can be larger than the diameter d4 of the light spot. At this time, the corresponding light spot on the measured object surface 6 at the position B reflects, returns through the dispersive objective lens 7 according to the original path, images to the position B, enters the camera 54 after passing through the light path 32 of the spectrometer, and obtains wavelength information through the intensity peak position of the light spot in the z direction in the camera 54, so as to obtain the height information of the measured object surface 6B' at this time, and so on, when the pin hole 421 moves by one Δ d1 every time, the height information of the measured object surface 6 in the Y direction is obtained; the distance Δ d1 is controlled by controlling the unit movement, i.e., the measurement distance d2 is controlled, and the resolution of the line spectrum confocal system in the Y direction of the embodiment of the invention can also be controlled. The resolution in the Y direction of this embodiment gets rid of the influence of insufficient resolution in the Y direction caused by the fact that the pitch of the small holes or the pitch of the optical fibers cannot be very small in the conventional scheme, and meanwhile, the movable range of the pinhole 421 solves the measurement range of the system in the Y direction, the movable range may be 1 to 200mm, depending on the specific light path design scheme, the user may reversely deduce the moving speed of the orifice plate 42 according to the required resolution in the Y direction, and the corresponding relationship is: the moving speed V = fd/m of the aperture plate 42, where f is the acquisition frequency of the detection assembly 5, i.e., the frame rate of the camera 54, d is the maximum moving distance of the aperture plate 42, m is the number of measurement acquisition points in the line length direction, i.e., the resolution in the line length direction, and correspondingly, a column of scanning time t of the measured object surface 6 in the line length direction of the line light source is t = m/f, and the user can obtain the actually required Y-direction resolution by changing the moving speed of the aperture plate 42.
For example, the magnification k =0.2 of the dispersion objective lens 7, the unit measuring distance d2 of the measured surface 6 is 5um, the diameter d3=50um of the pinhole 421 on the aperture plate 42, the measuring length of the measured surface 6 in the Y direction is 10mm, the frame rate of the camera 54 is 4000Hz, the unit moving distance d1=25um of the aperture plate 42 is Δ d1, due to the aberration, the diameter d4 of the spot irradiated on the measured surface is greater than 10um and greater than the measuring distance d2, so that the measuring resolution is not affected by the diameter of the spot, the camera 54 takes one picture when the aperture plate 42 moves 25um, the number m of the measuring acquisition points in the line length direction is 2000, that is, the resolution in the Y direction is 2000, the maximum moving distance of the aperture device is 50mm, the moving speed of the aperture device is 100mm/s, and the scanning time t =0.5s.
Example two
The scanning efficiency of a single pinhole 421 is relatively low, and in order to reduce the scanning time, the present embodiment adopts a multi-hole scanning manner, specifically, the present embodiment is different from the first embodiment in that the aperture plate 42 has n pinholes 421, n ≧ 2, and in the specific example of fig. 6, n =2, that is, the aperture plate 42 has 2 pinholes 421 along the linear length direction of the linear light source, and of course, the number of the pinholes 421 may also be other numbers greater than 2.
The hole module 4 of the embodiment can reduce the moving stroke of the moving mechanism 41, and the maximum moving distance d of the hole plate 42 is equal to the distance d5 between the adjacent needle holes 421, that is, in the case of measuring the length in the same y direction, the moving distance of the hole plate 42 in the y direction is only 1/n of that in the first embodiment, and the requirement on the moving mechanism 41 is reduced. Preferably, the distance d5 between the adjacent pinholes 421 and the diameter d3 of the pinholes 421 are d5 > 10d3, so as to avoid the mutual influence of the beams of the adjacent pinholes 421. The moving speed V '= ndf/m of the aperture plate 42 in this embodiment, where f is the acquisition frequency of the detection assembly 5, m is the number of measurement acquisition points in the line length direction, that is, the resolution in the line length direction, and correspondingly, a line of scanning time t' = m/nf of the object surface 6 along the line length direction of the line light source.
For example, the magnification k =0.2 of the dispersion objective 7, the unit measuring distance d2 of the measured surface 6 is 5um, the diameter d3=50um of the pinhole 421 on the aperture plate 42, the distance d5=1mm between the adjacent pinholes 421, 10 pinholes in total, the measuring length of the measured surface 6 in the Y direction is 10mm, the frame rate of the camera 54 is 4000Hz, the unit moving distance d1=25um of the aperture plate 42 is, the spot diameter d4 irradiated on the measured surface is larger than 10um and larger than the measuring distance d2 due to the aberration, so that the measuring resolution is not affected by the diameter of the optical spot, the camera 54 takes one picture when the aperture plate 42 moves 25um, the measuring acquisition point m in the line direction is 2000, that is, the resolution in the Y direction is 2000, the maximum moving distance of the pinhole device is 5mm, the moving speed of the pinhole device is 100mm/s, the scanning time t =0.05s, and has higher scanning efficiency compared with the first embodiment.
The above embodiments are only preferred embodiments of the present invention, and the scope of the present invention should not be limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are intended to be covered by the claims.
Claims (10)
1. A line-spectral confocal system, comprising:
the linear light source module is used for providing a linear light source;
the relay lens group is positioned on one side of the linear light source module along the light path;
the spectroscope is positioned on one side of the relay lens group along the light path;
the hole module is positioned on one side of the spectroscope along the light path and comprises a hole plate with at least one pinhole, and the pinhole is used for transmitting light;
the dispersive objective lens is positioned between the hole module and the surface to be measured; and a detection component;
the relay lens group images the line light source to the hole module, part of light rays passing through the dispersive objective lens are projected to a measured object surface, and part of light rays reflected by the measured object surface return to pass through the hole module and are collected by the detection assembly through the spectroscope; wherein the content of the first and second substances,
the hole module further comprises a moving mechanism, the moving mechanism drives the hole plate to reciprocate along the linear length direction of the linear light source within the irradiation range of the linear light source, and the moving mechanism comprises a control module for controlling the speed of the hole plate, so that the speed and the maximum moving distance of the hole plate meet the requirement of the resolution ratio in the linear length direction of the system.
2. The line spectral confocal system of claim 1, wherein the aperture plate has only one pinhole.
3. The line spectral confocal system of claim 2, wherein the moving speed of the aperture plate V = fd/m,
wherein, f is the acquisition frequency of the detection assembly, d is the maximum moving distance of the pore plate, and m is the number of measurement acquisition points in the line length direction.
4. The line spectral confocal system of claim 3, wherein a column scan time t of the object surface along the line length direction of the line light source is t = m/f.
5. The line spectral confocal system of claim 1, wherein the aperture plate has n pinholes along the line length of the line light source, n is greater than or equal to 2, and the maximum moving distance d of the aperture plate is equal to the distance d5 between adjacent pinholes.
6. The line spectral confocal system of claim 5, wherein the distance d5 between adjacent pinholes is related to the diameter d3 of the pinholes by d5 > 10d3.
7. The line spectral confocal system of claim 5, wherein the moving speed of the aperture plate V' = ndf/m, where f is the acquisition frequency of the detection assembly and m is the number of measurement acquisition points in the line length direction;
and a column of scanning time t' = m/nf of the object surface to be measured along the linear length direction of the linear light source.
8. The line spectrum confocal system of claim 2 or 7, wherein the aperture plate moves by a unit moving distance Δ d1 in a line length direction of the line light source, the moving unit measuring distance Δ d2, Δ d2= k Δ d1 of the light spot irradiated on the measured object surface, and k is the magnification of the dispersive objective lens.
9. The line spectroscopic confocal system of claim 8, wherein the diameter of the pinhole d3, the diameter of the light spot illuminated on the surface to be measured d4, d4 > kd3, k is the magnification of the dispersive objective, and the unit measuring distance d2 is smaller than the diameter of the light spot d4.
10. The line spectral confocal system of claim 1, 2 or 7,
the line light source emitted by the line light source module is a wide-spectrum line light source, and the ratio of the line length to the line width is more than 10; the spectral range of the linear light source is more than 100nm;
the relay lens group is also used for amplifying the linear light source to enable the line width of the linear light source to be larger than the diameter of the pinhole;
the spectroscope is used for separating an illumination light path from a spectrometer light path, the splitting ratio of the spectroscope to the detection component is 50;
the pore plate comprises a surface with light absorption, the cross section of the pinhole is trapezoidal, the small end part of the pinhole faces the dispersive objective lens, and the large end part of the pinhole faces the spectroscope; the surface of the orifice plate is provided with light absorption grooves;
the detection assembly comprises an achromatic astigmatic objective lens, a dispersive device, an achromatic focusing objective lens and an image acquisition unit.
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