CN111024000A - Long-range surface shape detector and detection method - Google Patents
Long-range surface shape detector and detection method Download PDFInfo
- Publication number
- CN111024000A CN111024000A CN201911420980.XA CN201911420980A CN111024000A CN 111024000 A CN111024000 A CN 111024000A CN 201911420980 A CN201911420980 A CN 201911420980A CN 111024000 A CN111024000 A CN 111024000A
- Authority
- CN
- China
- Prior art keywords
- plane
- reflected
- surface shape
- double
- range
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
- G01B11/25—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures by projecting a pattern, e.g. one or more lines, moiré fringes on the object
Landscapes
- Engineering & Computer Science (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
The invention relates to a long-range surface shape detector and a detection method, wherein the detector comprises a light source, a beam splitter, a double-reflector unit forming an equivalent pentaprism, a Fourier transform lens and an area array detector; the light source emergent beam passes through the beam splitter and the double-reflector unit to reach the surface of the optical device to be measured, and is reflected to the area array detector through the double-reflector unit, the beam splitter and the Fourier transform lens to form a measuring light spot; the double-reflector unit comprises two plane reflectors, the two plane reflectors can independently rotate along respective rotating shafts respectively, the two rotating shafts are positioned on the same plane, the included angle is 45 degrees, the plane reflectors are obliquely crossed with the rotating shafts of the plane reflectors, and the formed angle is set according to the quantity and the requirement so as to change the angle of an emergent light path reflected by the double-reflector unit through rotation and enable the emergent light path to be incident on the surface of the optical device to be measured in a normal incidence mode; the surface shape of the optical device to be detected is obtained through the rotation quantity of the two plane reflectors, so that the detection precision is improved.
Description
Technical Field
The invention belongs to the technical field of surface shape detection of long-range mirrors, and particularly relates to a long-range surface shape detector and a detection method.
Background
With the continuous development of science and technology, various application fields put higher requirements on the detection of the surface shape of the mirror surface. In order to improve the detection capability of the long-range profilometer, various system errors of the long-range profilometer need to be corrected or eliminated. Of these systematic errors, the most important one is introduced due to the slight difference between the optical elements used in the optical path system of the long-range profilometer itself and the ideal optical elements, which mainly appears in two aspects:
on one hand, the system error is introduced by the tiny processing difference between the surface shape of each reflection optical element in the optical path system and the surface shape of an ideal reflection optical element and the uneven material refractive index of the transmission optical element, and when a measuring beam is incident on a non-ideal optical element, the non-ideal optical element causes the direction of an emergent beam to slightly deviate from the ideal emergent direction, so that the angle measuring error is introduced;
on the other hand, the light beam reflected by the optical device to be measured can generate transverse movement on each optical element in the system along with the change of the measurement angle, and the larger the transverse movement amount is, the more errors are introduced to different points on the same optical element in the measurement system, and more system errors can be introduced. The amount of lateral shift, processing defects and aberrations all introduce angular measurement errors.
For example, in CN105737758A, the pp-LTP optical structure shown in fig. 1 has a phase plate 2', a beam splitter 3', a plane mirror 4', a pentaprism 5', and a fourier transform lens 7' of an f- θ angle detection system introduced into its detection optical path, which all introduce the above system errors, so that CN105737758A adopts a new structure of a single-aperture screen, so that the optical elements introducing errors only include the plane mirror and the fourier transform lens, thereby reducing the number of optical elements introducing system errors, reducing the amount of lateral shift, and improving the detection accuracy.
There is also a detection optical path structure disclosed in CN105737759A, in which the f- θ angle detection system is disposed on the mobile optical head, so that the structure is more compact, the amount of lateral shift is reduced, and the optical element introducing errors is only a fourier transform lens.
There is also a detection optical path structure disclosed in CN105758333A, and an f- θ angle detection system is also disposed on the moving optical head, and the optical element introducing the error is only a beam splitter.
There is also a detection optical path structure disclosed in CN105674913A, and the optical elements for introducing errors only include a beam splitter and a fourier transform lens.
As can be seen from the above, in the existing long-range profile measurement solutions, the purpose of reducing the optical elements and the optical elements introducing errors is achieved by structural changes, and the systematic errors cannot be completely or better eliminated, and the form of the surface shape of the measured optical device is fed back through the difference value between the falling points of the measuring light spots on the area array detector (CCD) of the f-theta angle detection system, and the problems of processing nonuniformity of the pixel points of the area array detector, inconsistent photoelectric response efficiency, consistency of electronic circuits and the like brought into system errors also inevitably exist, theoretically, the larger the distance between the Fourier transform lens and the area array detector is, the higher the resolving power is, in the current detection mode, the larger the distance is, the more errors are introduced into different points on an area array detector (CCD), and the contradiction exists.
Disclosure of Invention
In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a long-range surface shape detector and a detection method, which avoid the problem of a large number of system errors caused by surface shape errors, refractive index errors and traverse displacement of optical elements in a detection optical path, and achieve the effects of reducing introduction of system errors and improving detection accuracy.
In order to solve the technical problems, the invention adopts the following technical scheme:
the long-range surface shape detector comprises a light source, a beam splitter, a double-reflector unit forming a double-reflector equivalent to a pentaprism structure and an f-theta angle detection system, wherein the f-theta angle detection system comprises a Fourier transform lens and a planar array detector; an emergent light beam provided by the light source is reflected to the double-reflector unit through the beam splitter, then is reflected to the surface of the optical device to be measured through the double-reflector unit, is reflected to the beam splitter through the double-reflector unit after being reflected by the surface of the optical device to be measured, is transmitted to the area array detector through the Fourier transform lens after penetrating through the beam splitter, and forms a measuring light spot on the area array detector; the invention and creation points are as follows: the double-reflector unit comprises two plane reflectors, the two plane reflectors can independently rotate along respective rotating shafts, the rotating shafts of the two plane reflectors are positioned on the same plane, the included angle is 45 degrees (namely the two plane reflectors respectively use the normal of the double-reflector as the rotating shafts), the plane reflectors and the rotating shafts of the plane reflectors are in oblique intersection (oblique intersection: intersection but not vertical (solid geometry term)) so as to change the angle of an emergent light path reflected by the double-reflector unit through rotation and enable the emergent light path to be incident to the surface of the optical device to be measured in a normal incidence mode; and acquiring the surface shape related data of the optical device to be measured through the rotation quantity of the two plane reflectors.
The angle (solid geometry term) formed by the plane mirror and the rotating shaft of the plane mirror is set according to the measurement range requirement, namely the inclination angle of the plane mirror and the rotating shaft of the plane mirror is set according to the measurement range requirement, the value of the inclination angle also corresponds to the size of the complementary angle of the plane mirror and the corresponding reflecting surface (solid geometry term), and because the plane angle between the plane mirror and the corresponding reflecting surface is more intuitive, the description of the relevant angle is carried out according to the plane angle.
Compared with the prior art, the invention has the following beneficial effects:
1. the long-range surface shape detector of the invention arranges a double-reflector unit which forms a double-reflecting surface equivalent to a pentaprism structure in a detection light path, and rotates two plane reflectors of the double-reflector unit, the angle of the emergent light path reflected by the two plane reflectors can be changed, and the emergent light path is incident to the surface of the optical device to be measured in a normal incidence mode, because the light beam is vertically incident, the reflection light path of the detection point is also returned along the original path of the incident light path, and the light beam part before the light beam is incident to the double-reflector unit is consistent all the time, therefore, the landing points of the measuring light spots formed by the reflection light paths of different detection points can be consistent or all fall within a set landing point range (the absolute landing point consistency cannot be realized, so the concept of the landing point range is used), and the surface shape of the optical device to be measured is obtained through the rotation amount and the measuring position of the two plane mirrors. Thus, the surface shape detection condition is not fed back directly through the distance difference between the measuring light spots on the area array detector, but only as an intermediate reference and just as an effect observation point or a feedback point for the rotation adjustment of the two plane mirrors, the action positions of the light beams on each optical element on the detection light path are all fixed and are in the same point or a small range, including the area array detector! The problem that system errors can be introduced into each optical element in a detection light path is well solved, introduction of the system errors is effectively reduced, angle errors of each optical element (a transmission body, a Fourier lens and a CCD) introduced due to beam transverse displacement in a traditional system can be completely avoided, and detection precision is improved.
2. In the detection form of the invention, because the measured light spots have consistent falling points, the distance between the Fourier transform lens and the area array detector can be larger without introducing excessive errors at different points, thereby overcoming the contradiction in the existing form, improving the resolution capability of the used f-theta angle detection system and correspondingly improving the judgment precision of the consistency of the measured light spots when in detection use.
3. The angle is measured by a double-reflector unit, the measuring range is controlled by the angle size of an angle formed by the plane reflector and the rotating shaft of the plane reflector which are intersected with each other, namely the angle measuring range of the instrument is controlled (if the plane angle between the plane reflector and the corresponding reflecting surface is 1.25mrad, the system measuring range is +/-5 mrad), the surface shape angle measuring range (such as +/-5 mrad) is expanded to correspond to the angle adjusting range of the plane reflector by the double-reflector unit, the angle measuring accuracy of the instrument is better than 50 mrad theoretically within the angle measuring range of +/-5 mrad if the rotating angle of the plane reflector can realize the angle accuracy of 10 mrad, and the measuring mode is not limited by measuring distance. The measurement accuracy of the currently known maximum-accuracy long-range surface-shaped system can only achieve 50nrad within the range of about +/-250 mu rad.
Drawings
FIG. 1 is a schematic diagram of an optical path structure included in the long-range surface profile detector according to the embodiment;
FIG. 2 is a schematic diagram of an overall structure of the long-range surface profile detector according to the embodiment;
FIG. 3 is a schematic diagram of controlling the measurement range by rotation of a two mirror unit in an embodiment;
FIG. 4 is a diagram illustrating the effect of normal incidence and road reflection at a detection point in an embodiment (solid line);
FIG. 5 is a schematic diagram of a calibration process according to an embodiment;
FIG. 6 is a diagram illustrating a simulation of the relationship between angles associated with the exit light path during use in accordance with an exemplary embodiment;
FIG. 7 is a α angle transformation diagram of an embodiment in use;
FIG. 8 is a α angle transformation diagram of an embodiment in use;
FIG. 9 is a graph of the θ angle transformation in use of the exemplary embodiment;
FIG. 10 is a graph of the θ angle transformation in use of an embodiment;
the device comprises a light source 1, a beam splitter 2, a double-reflector unit 3, a plane reflector 31, a reflecting surface 4, a rotating shaft 5, an optical device 6 to be tested, a Fourier transform lens 7, an area array detector 8, an optical platform 9, a linear translation table 10, a shell 11, a single-hole screen 100 and a calibration piece 101.
Detailed Description
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
Referring to fig. 1 and 2, a long-range surface shape detector of an embodiment is used for surface shape detection of a surface of an optical device 6 to be detected, and includes a light source 1, a beam splitter 2, a dual-reflector unit 3 of a dual-reflector 4 forming a pentaprism-like structure, and an f-theta angle detection system, where the f-theta angle detection system includes a fourier transform lens 7 and a planar array detector 8; an emergent light beam provided by the light source 1 is reflected to the double-reflector unit 3 through the beam splitter 2, then is reflected to the surface of the optical device 6 to be measured through the double-reflector unit 3, is reflected to the beam splitter 2 through the double-reflector unit 3 after being reflected by the surface of the optical device 6 to be measured, is transmitted to the area array detector 8 through the Fourier transform lens 7 after penetrating through the beam splitter 2, and forms a measuring light spot on the area array detector 8; the invention and creation points are as follows: the double-reflector unit 3 comprises two plane reflectors 31, the two plane reflectors 31 can independently rotate along respective rotating shafts 5, the rotating shafts 5 of the two plane reflectors 31 are positioned on the same plane, and the included angle is 45 degrees (namely the two plane reflectors 31 respectively use the normal of the double-reflector 4 as the rotating shafts 5), the plane reflectors 31 and the rotating shafts 5 are in skew (in a solid geometric term, the skew is crossed but not vertical) and form an angle (in a solid geometric term, namely the tilt angle of the plane reflector 31 and the rotating shaft 5 is also corresponding to the size of a complementary angle of a plane angle between the plane reflector 31 and the corresponding reflecting surface 4), and the angle is set according to the quantity requirement so as to change the angle of an emergent light path reflected by the double-reflector unit 3 through rotation and enable the emergent light path to be incident to the surface of the optical device 6 to be measured in a normal incidence mode; the surface shape of the optical device 6 to be measured is obtained by the rotation amount of the two plane mirrors 31.
In the long-range surface shape detector of the embodiment, the angle of the emergent light path reflected by the double-reflector unit 3 can be changed by rotating the two plane reflectors 31 of the double-reflector unit 3, and the emergent light path is incident on the surface of the optical device 6 to be detected in a normal incidence mode, because the emergent light path is vertically incident, the reflected light path of the detection point returns according to the original path of the incident light path, and the light beam part before the incident light path is always consistent, therefore, the falling points of the measuring light spots formed by the reflected light paths of different detection points are consistent or all fall within the set falling point range, at this time, the falling point position of the measuring light spot is no longer a direct judgment value, only the rotation adjustment reference and observation feedback point of the plane reflector 31 is needed, and the rotation angles of the two plane reflectors 31 feed back the surface shape deflection angles corresponding to the different detection point positions, thereby, the surface shape of the optical device 6 to be detected can be obtained.
The surface shape of the optical device 6 to be measured is fed back by the rotation amount of the two plane mirrors 31. In such a form, the surface shape detection condition is not fed back directly through the distance difference between the measurement light spots on the f-theta angle detection system, but only as an intermediate reference, namely as an effect observation point or a feedback point for the rotation adjustment of the two plane mirrors 31; the detection light path is always kept on the same route, the position of the light beam on each optical element on the detection light path is fixed and is in the same point or a small range, the area array detector 8 in the f-theta angle detection system is included, when different angles are measured, the transverse displacement of the measuring light beam on each optical element is zero, the angle errors introduced between the optical elements when different angles are measured are the same, no error exists in the relative difference value between the measuring angles, and the relative difference value between the angles is a required measurement value which can feed back the surface shape of the optical device 6 to be measured. Therefore, the problem that system errors are possibly introduced into each optical element in a detection optical path is well solved, the introduction of the system errors is effectively reduced, and the detection precision is improved. The mode of feeding back the surface shape of the optical device 6 to be detected through the rotation quantity of the two plane reflectors 31 also changes the adjustable range into the range of 0-pi radian value for adjustment, thereby amplifying the reading precision, subdividing the reading interval and obtaining the effect of further improving the detection precision.
The rotation accuracy that can be achieved by the current mechanical structure can reach 10 μ rad of angular accuracy (for example, the existing AEROTECH precision rotary table can achieve a positioning accuracy of 2arc sec, about 10urad, if it is desired to achieve a higher measurement accuracy, a higher positioning accuracy rotary table can be selected), and the required rotation adjustment of the plane mirror 31 and the adjustment of the optical path angle can be completely supported. The last two plane mirrors 31 still have the problem of introducing a traverse amount, but since the distance between the two plane mirrors 31 is set adjacently, the introduced traverse amount is very small and the influence on the detection accuracy is negligible, for example, the traverse amount introduced by the two mirror unit 3 is very small because the plane angle between the plane mirror 31 and the corresponding aforementioned reflecting surface 4 is set to 1.25mrad, the exit light deflection angle thereof is 2.5mrad, the distance between the two plane mirrors 31 is set to 3cm, the traverse amount is introduced on the second plane mirror 31 of the two mirror unit 3 is about 150 μm, and the diameter of the spot is usually 1mm (or even larger); the invention and Chinese patent application, application number: 201911303272.8, the distance between the two plane mirrors 31 is still larger than the double wedge of this solution.
In this case, the intersection of the plane mirror 31 with its axis of rotation 5, i.e. the foot (in solid geometric terms), is located in its central region.
Therefore, the plane mirror 31 can be ensured to receive light beams all the time in the process of rotating along the rotating shaft 5 of the plane mirror so as to ensure the using effect, the area of the plane mirror 31 can be correspondingly reduced, and the instrument is prevented from being larger in size.
When the outgoing beam provided by the light source 1 is reflected by the beam splitter 2 and then enters the first plane mirror 31 of the two-mirror unit 3, it preferably enters the intersection point of the first plane mirror 31 and the rotating shaft 5 thereof. As shown in fig. 4.
Thus, the amount of lateral movement introduced by the two-mirror unit 3 is further reduced, and the problem that the first plane mirror 31 introduces an additional error due to the amount of lateral movement introduced by the rotation can be avoided.
The light source 1, the beam splitter 2, the Fourier transform lens 7 and the area array detector 8 are fixedly arranged, and the two plane reflectors 31 are arranged on the movable optical head; the mobile optical head comprises a shell 11, and the two plane mirrors 31 are arranged in the shell 11. The movable optical head is installed on a linear translation table 10, the linear translation table 10 is slidably arranged above an optical platform 9 so as to drive the movable optical head to slide and detect an optical device 6 to be detected arranged on the optical platform 9, and the light source 1, the beam splitter 2, the Fourier transform lens 7 and the area array detector 8 are fixedly arranged on the side wall of the optical platform 9.
Thus, the necessary infrastructure is provided, and the moving optics head, linear translation stage 10 and optical stage 9 are all prior art and will not be described further herein.
Wherein the light source 1 is a collimated light source 1 such that the provided outgoing light beam is a collimated light beam, and preferably a collimated incoherent beamlet. In practice, coherent light, such as a laser light source, may be optionally used to provide the outgoing beam as a parallel coherent beamlet.
The angle is measured by the double-reflector unit 3, the angle measuring range of the detector is controlled by the size of the plane angle, if the plane angles are all 1.25mrad, the measuring range is +/-5 mrad, as shown in fig. 3, when the plane angles of the two plane reflectors 31 and the corresponding reflecting surface 4 are consistent, the emergent light path reflected by the double-reflector unit 3 reaches the maximum deflection angle of 5mrad, when the detector is used, the angle of the emergent light path reflected by the double-reflector unit 3 can be (randomly) changed within the range of the elliptical cone-like geometry of about +/-5 mrad on a meridian plane and about +/-4.6 mrad on an arc sagittal plane through the rotation of the two plane reflectors 31, so that an incident point incident at a normal line can be found in the measuring range, as shown in fig. 4, and if the incident point cannot be found, the posture of the optical device 6 to be measured on the optical platform 9 is not placed, and the range is beyond the measuring range; the incident point and the set detection point are not overlapped normally, the relative position of the incident point and the set detection point can also be calculated through the rotation angle of the plane reflecting mirror 31, and the surface shape to be measured can be constructed through the integration between the angle and the position.
The two plane angles are enabled to be consistent in orientation, the emergent light path reflected by the double-reflector unit 3 reaches the maximum deflection angle of 5mrad, the two plane angles are enabled to be consistent in orientation and rotate in the same direction, and the emergent light path circumferentially rotates at the maximum deflection angle and can stay at any position on the circumferential direction of the elliptical cone.
Referring to fig. 2, the invention further provides a long-range surface shape detection method, which is performed based on the long-range surface shape detector and includes the following steps:
1) placing the optical device 6 to be tested on an optical platform 9;
2) the linear translation stage 10 drives the shell 11 of the mobile optical head to slide to a first detection point, the light source 1 provides an emergent light beam, the emergent light beam is reflected by the surface of the optical device 6 to be detected, and a measurement light spot is formed on the area array detector 8, wherein the light path is a dotted line light path in the figure;
3) rotating the two plane reflectors 31 to enable the emergent light paths to enter the surface of the optical device to be measured 6 in a normal incidence mode, judging whether the measuring light spots are formed in a unified set range on the area array detector 8 (namely whether the measuring light spots fall in a set falling point range), and adjusting the dotted light paths in the graph to be coincident with the solid light paths;
if the measurement spot is formed within the unified setting range, outputting (recording) rotation data (rotation angle) of the two plane mirrors 31;
if the measurement light spot is not formed in the unified setting range, continuing to rotate and adjust according to the measurement data until the measurement light spot is formed in the unified setting range, and then outputting the rotation data of the two plane reflectors 31; in implementation, if the measuring light spot is not formed in the unified setting range, the corresponding normal angle direction can be judged according to the forming position of the measuring light spot, so that the rotation angle of the double-reflector unit 3 is corrected, and the rotation adjustment of the two plane reflectors 31 is facilitated;
4) the linear translation stage 10 drives the movable optical head to slide to the next detection point, the light source 1 provides an emergent light beam, the emergent light beam is reflected by the surface of the optical device to be detected 6, and a measurement light spot is formed on the area array detector 8;
5) repeating the steps 3) and 4) until the set rotation data of the two plane mirrors 31 corresponding to all the detection points are output;
the measurement light spots formed on the area array detector 8 by different detection points all fall within the same set fall point range (the unified set range), that is, the fall points are consistent, and the absolute fall point consistency cannot be realized, so that the fall points are limited within a smaller set range by combining the detection mode of the area array detector 8.
6) The surface shape of the optical device 6 to be measured can be obtained through the obtained rotation data and the measurement position.
Referring to fig. 5, before step 1), a calibration operation of the detector is further included, and the calibration operation includes determining the uniform setting range through a measurement spot formed on the area array detector 8 by a reflected light path returned by the outgoing light path after being reflected by the two-mirror unit 3. The method specifically comprises the following steps:
a) a single-hole screen 100 is closely arranged at the incident position of parallel light on the surface of the beam splitter 2 facing the light source 1;
b) placing a calibration piece 101 on the optical platform 9;
c) parallel light emergent beams provided by the light source 1 penetrate through a screen hole of the single-hole screen 100 and are reflected to the double-reflector unit 3 through the beam splitter 2, are reflected by the double-reflector unit 3 and then are incident on the surface of the calibration piece 101, and are reflected by the surface of the calibration piece 101 to form a reflection light path; according to the reversible optical path, at this time, if the reflected optical path fails to return by the original path of the incident optical path, the reflected optical path is incident on the non-screen hole position on the single-hole screen 100 and is blocked, and only the reflected optical path returned by the original path of the incident optical path can pass through the screen hole of the single-hole screen 100. Therefore, the attitude of the standard component 101 only needs to be adjusted, so that the reflected light path returns along the original path of the incident light path (normal incident attitude), passes through the screen hole of the single-hole screen 100, then penetrates through the beam splitter 2 and is transmitted to the area array detector 8 through the fourier transform lens 7, a measurement light spot is formed on the area array detector 8, and the unified setting range can be determined through the measurement light spot. In implementation, the unified setting range, the screen hole diameter of the single-hole screen 100, and the like may be selected according to the detection parameter index to be achieved by the detector, and are not particularly limited.
The effect of the method is the same as the effect described above, and is not described herein again. In implementation, if the device is used as a set of integral equipment for convenient and automatic use, the two plane mirrors 31 of the dual-mirror unit 3 can be respectively arranged in a cylindrical carrier which is fixedly arranged in the shell 11, the rotatable plane mirrors 31 are provided in the cylindrical carrier, the axis of the cylindrical carrier can be coincided with the rotating shaft 5 of the plane mirrors 31, the device also can comprise an automatic controller which is electrically connected with the area array detector 8, the linear translation stage 10 and a driving unit for driving the plane mirrors 31 to rotate, and a calibration device is used for determining the falling point range of the measuring light spot on the area array detector 8; the automatic controller controls the distance between different detection points on the surface of the optical device 6 to be measured through a pre-written program and the unified setting range of the measurement light spots on the area array detector 8, judges whether the measurement light spots corresponding to one detection point are formed in the unified setting range on the area array detector 8 or not, and if the measurement light spots are not formed in the unified setting range, the automatic controller can correct and drive the plane mirror 31 to rotate by combining with the actual falling point condition, so that the measurement light spots fall in the unified setting range. And outputting the rotation angle data to be used as a data basis for feeding back the surface shape of the optical device 6 to be measured. And (4) according to different standards, obtaining the data to be judged through data basis conversion to judge the surface shape of the optical device 6 to be tested.
Referring to fig. 6-10, assuming that the light path of the light reflected by the dual mirror unit 3 travels in the opposite direction of the z axis and the moving optical head scans along the y axis, the plane angle between the plane mirror 31 and the reflective surface 4 is set to 1.25mrad (range ± 5mrad), the dual mirror unit 3 can be initially set to change in the opposite direction to (-1.66501rad, 1.4757rad), and the light path of the light is incident on the surface to be measured (the surface of the optical device to be measured) at angles α ═ 0 and θ ═ 0, and if the normal direction of the measurement point of the surface to be measured is (-0.003, -0.001, 0.999996), the angle measured by the f- θ system is about (-0.00599rad, -0.00201rad), and the angle of the normal (α, θ) of the measurement point is about (-0.003rad, -0.001rad) calculated by dividing 2 from the measured data by the f- θ system, and the relationship between the rotation angle of the two plane mirrors 31 and the light path direction can be calculated according to the light path tracing, and the relationship is omitted in this example:
wherein
The first plane mirror 31 to which an incident beam is incident among the two plane mirrors 31 is rotated by an angle about its rotation axis,
the second plane mirror 31 is angularly rotated about its rotation axis. The above equation can be approximated as:
further it can be calculated that:
wherein:
A＝-0.002309691
B＝0.002499991
based on approximate calculation
And
when the two plane mirrors 31 are rotated, the f-theta system measures the reflected light path angle to be about (-908nrad, 413nrad), and based on the measured value, the rotation angle correction can be calculated as follows:
wherein:
Δα＝-908/2
Δθ＝4L3/2
the rotation angles of the two corrected plane reflectors are as follows:
at the moment, the emergent light path is incident to the surface to be measured in the normal direction (with an error of about 10nrad) of the surface to be measured, and α and theta can be obtained by calculation according to the actual rotation angle of the two plane reflectors after the emergent light path is determined to be incident to the surface to be measured in the normal incidence mode according to the measured value of the f-theta system.
According to
Can calculate the rotation of two plane mirrors respectively
The measurement precision at different measurement angles (as shown in figures 7-10) shows that the theoretical measurement precision of the sample system is better than 50nrad in the set measurement range.
During actual detection, the direction of an emergent light path changes along with the rotation of the double-reflector unit, so that a measuring point slightly deviates, and at the moment, the rotation angles of the two plane reflectors need to be corrected for many times according to f-theta system feedback data. And judging whether the emergent light path enters the surface to be measured in the normal direction or not within a limited range according to the measured angle of the f-theta system, and calculating according to the rotation angles of the two plane reflectors to obtain the angle of the normal direction of the measuring point.
When the system is implemented, the rotating shaft of the plane mirror can select other angles, and the system is correspondingly adjusted.
Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.
Claims (10)
1. The long-range surface shape detector comprises a light source, a beam splitter, a double-reflector unit forming an equivalent pentaprism, andf-θan angle detection system is arranged on the base plate,f-θthe angle detection system comprises a Fourier transform lens and an area array detector; an emergent light beam provided by the light source is reflected to the double-reflector unit through the beam splitter, then is reflected to the surface of the optical device to be measured through the double-reflector unit, is reflected to the beam splitter through the double-reflector unit after being reflected by the surface of the optical device to be measured, is transmitted to the area array detector through the Fourier transform lens after penetrating through the beam splitter, and forms a measuring light spot on the area array detector; the method is characterized in that: the double-reflector unit comprises two plane reflectors, the two plane reflectors can independently rotate along respective rotating shafts, the rotating shafts of the two plane reflectors are positioned on the same plane, the included angle is 45 degrees, the plane reflectors and the rotating shafts of the plane reflectors are obliquely crossed, and the formed angle is set according to a quantity requirement so as to change the angle of an emergent light path reflected by the double-reflector unit through rotation and enable the emergent light path to be incident on the surface of the optical device to be measured in a normal incidence mode; the surface shape of the optical device to be measured is obtained through the rotation quantity of the two plane reflectors.
2. The long-range surface shape detector according to claim 1, wherein: the intersection point of the plane mirror and its rotation axis is located in its middle region.
3. The long-range surface shape detector according to claim 1, wherein: the intersection point of the plane reflector and the rotating shaft thereof is positioned in the middle area; the emergent light beam provided by the light source is reflected by the beam splitter and then enters the first plane reflector of the double-reflector unit, and then enters the intersection point of the first plane reflector and the rotating shaft of the first plane reflector.
4. The long-range surface shape detector according to claim 1, wherein: the light source, the beam splitter, the Fourier transform lens and the area array detector are fixedly arranged, and the two plane reflectors are arranged on the movable optical head; the movable optical head comprises a shell, and the two plane reflectors are arranged in the shell.
5. The long-range surface shape detector according to claim 4, wherein: the movable optical head is installed on the linear translation table, the linear translation table is slidably arranged above the optical platform so as to drive the movable optical head to slide and detect an optical device to be detected, the optical device to be detected is arranged on the optical platform, and the light source, the beam splitter, the Fourier transform lens and the area array detector are fixedly arranged on the side wall of the optical platform.
6. The long-range surface shape detector according to claim 5, wherein: the light source is a collimated light source to provide an outgoing beamlet of collimated light.
7. The long-range surface shape detector according to claim 6, wherein: the light source is an incoherent light source.
8. The long-range surface shape detection method is characterized by comprising the following steps: the method is carried out on the basis of the long-range surface shape detector of any one of claims 5 to 7, and comprises the following steps:
1) placing an optical device to be tested on an optical platform;
2) the linear translation stage drives the movable optical head to slide to a first detection point, an emergent light beam provided by the light source is reflected by the surface of the optical device to be detected, and a measurement light spot is formed on the area array detector;
3) rotating the two plane reflectors to enable the emergent light paths to be incident to the surface of the optical device to be measured in a normal incidence mode, and judging whether the measuring light spots are formed in a unified set range on the area array detector;
if the measuring light spot is formed in the unified setting range, outputting rotation data of the two plane reflectors;
if the measuring light spot is not formed in the unified setting range, continuing to rotate and adjust until the measuring light spot is formed in the unified setting range, and then outputting rotation data of the two plane reflectors;
4) the linear translation stage drives the movable optical head to slide to the next detection point, an emergent light beam provided by the light source is reflected by the surface of the optical device to be detected, and a measurement light spot is formed on the area array detector;
5) repeating the steps 3) and 4) until the set rotation data of the two plane reflectors corresponding to all the detection points are output;
6) and obtaining the surface shape of the optical device to be measured through the obtained rotation data.
9. The long-range surface shape detection method according to claim 8, characterized in that: before the step 1), calibrating the detector, wherein the calibrating operation comprises determining the unified setting range through a measuring light spot formed on the area array detector by a reflection light path returned by the emergent light path primary path after being reflected by the double-reflector unit.
10. The long-range surface shape detection method according to claim 9, characterized in that: the calibration operation comprises the following steps:
a) a single-hole screen is closely arranged on the beam splitter;
b) placing a calibration piece on the optical platform;
c) an emergent light beam provided by the light source penetrates through a screen hole of the single-hole screen and is reflected to the two plane reflectors through the beam splitter, an emergent light path reflected by the two plane reflectors is incident on the surface of the calibration piece, and a reflected light path is formed through the surface reflection of the calibration piece;
and adjusting the posture of the calibration part to enable the reflected light path to return along the original path of the emergent light path after being reflected by the double-reflector unit, penetrate through the screen hole of the single-hole screen, penetrate through the beam splitter and are transmitted to the area array detector through the Fourier transform lens, and a measuring light spot is formed on the area array detector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911420980.XA CN111024000B (en) | 2019-12-31 | 2019-12-31 | Long-range surface shape detector and detection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911420980.XA CN111024000B (en) | 2019-12-31 | 2019-12-31 | Long-range surface shape detector and detection method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111024000A true CN111024000A (en) | 2020-04-17 |
| CN111024000B CN111024000B (en) | 2021-07-27 |
Family
ID=70201696
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911420980.XA Active CN111024000B (en) | 2019-12-31 | 2019-12-31 | Long-range surface shape detector and detection method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111024000B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112986189A (en) * | 2021-02-24 | 2021-06-18 | 中国科学院长春光学精密机械与物理研究所 | Reflection measuring device |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2079982A1 (en) * | 2006-10-16 | 2009-07-22 | Robert Bosch GmbH | Method for determining the axis of rotation of a vehicle wheel |
| CN102620842A (en) * | 2012-04-10 | 2012-08-01 | 中国科学院光电技术研究所 | Detection device and method for detecting optical surface shape of pinhole diffraction spherical wave |
| CN103245303A (en) * | 2013-05-17 | 2013-08-14 | 中国工程物理研究院激光聚变研究中心 | Multi-pose large-caliber plane optical element surface shape detecting device and method |
| CN103322939A (en) * | 2013-06-26 | 2013-09-25 | 中国科学院上海光学精密机械研究所 | Wax plate face shape on-line real-time measurement device of annular polisher |
| CN104034279A (en) * | 2014-06-14 | 2014-09-10 | 中国科学院光电技术研究所 | Detection device and method for splicing and measuring surface shape by utilizing small-hole diffraction wave surface |
| CN104034281A (en) * | 2014-06-16 | 2014-09-10 | 浙江大学 | Optical self-focusing probe used for free-form surface topography measurement |
| CN104395813A (en) * | 2013-06-28 | 2015-03-04 | 英特尔公司 | MEMS scanning mirror light pattern generation |
| CN105737758A (en) * | 2016-02-24 | 2016-07-06 | 中国科学院上海应用物理研究所 | Long trace profile |
-
2019
- 2019-12-31 CN CN201911420980.XA patent/CN111024000B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2079982A1 (en) * | 2006-10-16 | 2009-07-22 | Robert Bosch GmbH | Method for determining the axis of rotation of a vehicle wheel |
| CN102620842A (en) * | 2012-04-10 | 2012-08-01 | 中国科学院光电技术研究所 | Detection device and method for detecting optical surface shape of pinhole diffraction spherical wave |
| CN103245303A (en) * | 2013-05-17 | 2013-08-14 | 中国工程物理研究院激光聚变研究中心 | Multi-pose large-caliber plane optical element surface shape detecting device and method |
| CN103322939A (en) * | 2013-06-26 | 2013-09-25 | 中国科学院上海光学精密机械研究所 | Wax plate face shape on-line real-time measurement device of annular polisher |
| CN104395813A (en) * | 2013-06-28 | 2015-03-04 | 英特尔公司 | MEMS scanning mirror light pattern generation |
| CN104034279A (en) * | 2014-06-14 | 2014-09-10 | 中国科学院光电技术研究所 | Detection device and method for splicing and measuring surface shape by utilizing small-hole diffraction wave surface |
| CN104034281A (en) * | 2014-06-16 | 2014-09-10 | 浙江大学 | Optical self-focusing probe used for free-form surface topography measurement |
| CN105737758A (en) * | 2016-02-24 | 2016-07-06 | 中国科学院上海应用物理研究所 | Long trace profile |
Non-Patent Citations (3)
| Title |
|---|
| A.J.MORRISON: "The shape and behaviour of a granular bed in a rotating drum using Eulerian flow fields obtained from PEPT", 《CHEMICAL ENGINEERINGSCIENCE》 * |
| 刘斌: "长程大型非球面轮廓测量仪的研究", 《激光与光电子母进展》 * |
| 童新宇: "长程面形仪测量数据的拟合方法", 《核技术》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112986189A (en) * | 2021-02-24 | 2021-06-18 | 中国科学院长春光学精密机械与物理研究所 | Reflection measuring device |
| CN112986189B (en) * | 2021-02-24 | 2022-02-11 | 中国科学院长春光学精密机械与物理研究所 | Reflection measuring device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111024000B (en) | 2021-07-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN211085268U (en) | Adjusting system for optical guide rail distance measuring device | |
| TW571090B (en) | Surface inspection system | |
| US11648629B2 (en) | Laser processing apparatus, laser processing method, and correction data generation method | |
| US7982882B2 (en) | Optical wave interference measuring apparatus | |
| CN107607056B (en) | Laser morphology detector | |
| CN109471090B (en) | Detection method of non-coaxial scanning laser radar receiving system | |
| US8059278B2 (en) | Optical wave interference measuring apparatus | |
| US6594006B1 (en) | Method and array for detecting the position of a plane scanned with a laser scanner | |
| US6504608B2 (en) | Optical measurement arrangement and method for inclination measurement | |
| JP2005201656A (en) | Method for measuring noncontact surface shape | |
| JPS62125646A (en) | Light beam aligner | |
| JP2009069151A (en) | Means and method for determining space position of transfer element in coordinate measuring device | |
| CN111024000B (en) | Long-range surface shape detector and detection method | |
| CN111426449A (en) | Method for calibrating parallelism of optical axes of multiple autocollimators | |
| JPH10318718A (en) | Optical height detecting device | |
| CN110926367B (en) | Long-range optical surface shape detection device and detection method | |
| CN113702007B (en) | Calibration device and calibration method for off-axis beam axial difference | |
| CN111043990B (en) | Autocollimator and use method thereof | |
| JPH0613999B2 (en) | Deviation measuring device for optical components | |
| JPS5924819A (en) | Mechanism for aligning optical axis of interference measuring device | |
| JPH04162337A (en) | Electron beam device | |
| JP7536927B2 (en) | Apparatus and method for geometrically measuring an object | |
| JP2755427B2 (en) | Device for scanning light beams parallel to a fixed axis and strictly flat | |
| CN114236743A (en) | Calibration system and method for plane mirror array | |
| JPH0669097A (en) | Alignment accuracy measuring device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20230525 Address after: 230000 B-1015, wo Yuan Garden, 81 Ganquan Road, Shushan District, Hefei, Anhui. Patentee after: HEFEI MINGLONG ELECTRONIC TECHNOLOGY Co.,Ltd. Address before: No. 69 lijiatuo Chongqing District of Banan City Road 400054 red Patentee before: Chongqing University of Technology |