Six-dimensional motion parameter optical measurement system

Abstract

The invention discloses a six-dimensional motion parameter optical measurement system, which comprises a polaroid of which the upper surface is plated with a semi-transparent and semi-reflective film, an X-direction and Y-direction displacement and center rotation measurement light path lens, an X-direction and Y-direction inclination and Z-direction displacement measurement light path lens and a detection controller, the detection controller is in communication connection with the XY-direction displacement and center rotation measurement light path lens and the XY-direction inclination and Z-direction displacement measurement light path lens. By means of the mode, the six-dimensional motion parameter optical measurement system can measure six parameters including xyz displacement, xy angle inclination and rotation around a center shaft in the motion process of a measured object at the same time, the detection efficiency of voice coil motor motion stability is effectively improved, and the detection accuracy and stability are effectively improved; and the size of the system can be reduced and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of optical measurement systems, and in particular to a six-dimensional motion parameter optical measurement system. Background Art

[0002] Currently, when testing the motion stability of a voice coil motor, the traditional detection method is to place a reflector above the motor to optically detect the changes in the motion posture of the voice coil motor in the XYZ direction. However, it is impossible to simultaneously detect the six dimensions of XYZ motion posture, XY tilt, and rotation angle around the central axis. Different optical measurement systems are required to perform batch detection on the objects to be tested. The detection efficiency is low and it is easy to affect the detection accuracy, so it needs to be improved. Summary of the Invention

[0003] In order to solve the above technical problems, a technical solution adopted by the present invention is: Provided is a six-dimensional motion parameter optical measurement system, comprising: a polarizer with a semi-transparent and semi-reflective film coated on its upper surface, an optical path lens for measuring XY displacement and center rotation, an optical path lens for measuring XY tilt and Z displacement, and a detection controller, wherein the polarizer is disposed above an object to be measured, and the detection controller is communicatively connected to the optical path lens for measuring XY displacement and center rotation, and the optical path lens for measuring XY tilt and Z displacement, respectively; The XY-axis displacement and center rotation measurement optical path lens includes a group of displacement and rotation measurement optical path components, a third optical lens component, a first detector, a sixth optical lens component and a fourth detector. The displacement and rotation measurement optical path component includes a first illumination light source, a first optical lens component, an aperture stop, a first spectrometer, a second optical lens component, the sixth optical lens component and the fourth detector are sequentially arranged from top to bottom below the object to be measured, and the fourth detector is on the focal plane of the sixth measurement optical path component. The second optical lens component, the third optical lens component and the first detector are sequentially arranged from bottom to top above the polarizer, and the first detector is arranged on the focal plane of the optical system composed of the second optical lens component and the third optical lens component. A beam splitter is obliquely disposed between the second optical lens assembly and the third optical lens assembly; an aperture stop is disposed between the first beam splitter and the first optical lens assembly and is located on the image plane of the first optical lens assembly; a first illumination light source is coaxially disposed with the first optical lens assembly on one side of the first beam splitter, so that linearly polarized light emitted by the first illumination light source sequentially passes through the first optical lens assembly, the first beam splitter, and the second optical lens assembly to form an XY displacement detection optical path and a center rotation detection optical path; the XY displacement detection optical path passes through the object to be measured, the second optical lens assembly, the first beam splitter prism, and the third optical lens assembly, and is imaged on the first detector; the center rotation detection optical path passes through the object to be measured and the sixth optical lens assembly, and is imaged on the fourth detector; The XY-direction tilt and Z-direction displacement measurement optical path lens includes a group of tilt and displacement measurement optical path components, a second reflector, a third detector, a fifth optical lens component, and a second detector. The tilt and displacement measurement optical path component includes a second illumination light source, a first reflector, a fourth optical lens component, and a second spectrometer. The second illumination light source and the first reflector are arranged on one side of the second optical lens component and above the polarizer. The fourth optical lens component, the fifth optical lens component, and the second detector are coaxially and tilted from bottom to top on the other side of the second optical lens component, and the second detector is located in the fifth optical lens component. On the focal plane of the component, the second beam splitter is arranged between the fourth optical lens assembly and the fifth optical lens assembly, the third detector is arranged on the side of the second beam splitter, and the second reflector is arranged between the second beam splitter and the third detector, so that the light beam emitted by the second illumination light source is reflected by the first reflector, the object to be measured and the fourth optical lens assembly in sequence to form a Z displacement detection light path and an XY angle detection light path, the Z displacement detection light path passes through the second beam splitter and the fifth optical lens assembly and is incident on the second detector, and the XY angle detection light path passes through the second beam splitter and the second reflector and is incident on the third detector.

[0004] In a preferred embodiment of the present invention, the light splitting element includes a light splitting prism or a graticule.

[0005] In a preferred embodiment of the present invention, the light emitted by the first illumination light source is linearly polarized light with a polarization direction in the x direction, and the light emitted by the second illumination light source is a collimated light beam.

[0006] In a preferred embodiment of the present invention, the first illumination light source, the first optical lens assembly, and the second optical lens assembly constitute a Köhler illumination system, the first illumination light source is located on the object plane of the first optical lens assembly, and the front focal plane of the second optical lens assembly coincides with the aperture stop.

[0007] In a preferred embodiment of the present invention, the first detector and the third detector are two-dimensional PSDs or area array cameras, the second detector is a one-dimensional PSD or area array camera, and the fourth detector is a light intensity sensor.

[0008] In a preferred embodiment of the present invention, the second optical lens assembly, the first beam splitter prism, and the third optical lens assembly form a double-telecentric imaging optical system.

[0009] In a preferred embodiment of the present invention, the inclination angle of the fourth optical lens assembly, the fifth optical lens assembly and the second detector is the same as the incident angle of the incident light; preferably, the inclination angle is 20-35°.

[0010] A control method for a six-dimensional motion parameter optical measurement system, comprising the following steps: (1) First, fix the polarizer on the object to be measured so that the polarizer moves with the movement of the object to be measured, and turn on the first and second illumination sources at the same time; (2) After the object to be tested is powered on, the XYZ direction position and the XY tilt position of the object to be tested are adjusted to the initial position, and the object to be tested and the polarizer are rotated around the center to the maximum position. At this time, the polarization direction of the polarizer is the same as the direction of the linearly polarized light, and the maximum light intensity I0 detected by the fourth detector is obtained; (3) adjusting the input current of the object to be tested according to a preset Z-axis movement distance threshold, so that the object to be tested moves a predetermined distance along the Z-axis direction; wherein the Z-axis movement distance threshold includes a positive displacement threshold and a negative displacement threshold. When the position of the object to be tested in the Z-axis direction moves from the initial position to the positive displacement threshold, from the positive displacement threshold to the negative displacement threshold, and finally from the negative displacement threshold back to the initial position, a detection cycle is formed; (4) When the object to be tested and the polarizer are moving, the XY displacement and center rotation measurement optical path lens is used to detect the displacement of the object to be tested in the XY axis direction and the rotation amount of the object to be tested around the center axis, and the XY tilt and Z displacement measurement optical path lens is used to detect the angular tilt of the object to be tested in the XY axis direction and the displacement in the Z axis direction; (4.1) The linearly polarized light emitted by the first illumination light source passes through the first optical lens assembly, the first beam splitter prism, and the second optical lens assembly to form an XY displacement detection optical path and a center rotation detection optical path, which are uniformly illuminated on the surface of the polarizer coated with a semi-transparent and semi-reflective film; (4.1.1) The XY displacement detection light path is reflected by the polarizer and then returns upward. The reflected light passes through the second optical lens assembly, the first beam splitter prism, and the third optical lens assembly before being imaged on the first detector. The detection controller obtains the real-time detection value of the first detector at a preset detection frequency and calculates the x- and y-axis displacement values of the object under test based on the real-time detection value of the first detector; (4.1.2) The central rotation detection light path is incident on the surface of the polarizer, and the transmitted light is incident on the surface of the fourth detector through the sixth optical lens assembly. The detection controller obtains the real-time detection value of the fourth detector at a preset detection frequency, and obtains the angle value of the object under test rotating about the central axis based on the real-time detection value of the fourth detector; (4.2) The small-diameter collimated light emitted by the second illumination source is deflected by the first reflector and incident on the surface of the polarizer. The reflected light passes through the fourth optical lens assembly and the second beam splitter prism to form the Z displacement detection optical path and the XY angle detection optical path; (4.2.1) The XY angle detection light path passes through the second reflector and is incident on the third detector. The detection controller obtains the real-time detection value of the third detector at a detection frequency preset by the detection controller, and the inclination value of the object under test in the x-axis and y-axis directions is obtained based on the real-time detection value of the third detector; (4.2.2) The Z-displacement detection light path passes through the fifth optical lens assembly and is incident on the second detector. The detection controller obtains the real-time detection value of the second detector at a detection frequency preset by the detection controller, and the Z-direction displacement value of the object to be measured is obtained based on the real-time detection value of the second detector; (5) The detection controller generates and saves a measurement value group at a preset frequency, wherein a measurement value group includes a real-time displacement value in the x-direction, a real-time displacement value in the y-direction, a real-time angle value of the central axis rotation, a real-time tilt value of the x-direction angle, a real-time tilt value of the y-direction angle, and a real-time displacement parameter value in the z-direction corresponding to the current generation time.

[0011] In a preferred embodiment of the present invention, in step (4), (a) Given the magnification of the bi-telecentric imaging optical system as β1 and the distance the object moves in the x-axis direction as AB, the real-time x-direction displacement detected by the first detector is A1B1 = AB × β1. Similarly, the y-direction displacement detected by the first detector is calculated. (b) When the object to be tested and the polarizer are moving, all the real-time light intensity values I detected by the fourth detector during the detection period are obtained to calculate the real-time angle value of the object to be tested rotating around the central axis in real time. ; (c) Obtain the focal length f of the fourth optical lens assembly and the movement distance A'B' detected by the third detector. The real-time tilt angle of the object under test along the X-axis is a = arctan(A'B' / f) / 2. Similarly, the tilt angle of the object under test along the Y-axis is calculated. (d) Obtain the angle β between the direction of the emitted light of the second illumination light source and the normal of the object to be measured, the magnification β2 of the optical system composed of the fifth optical lens assembly and the fourth optical lens assembly, and the movement distance A1'B1' detected by the second detector. The real-time movement distance z of the object to be measured along the Z-axis is = A1'B1' × β2 × cosβ / sin(2β).

[0012] In a preferred embodiment of the present invention, in step (5), the detection controller obtains the query condition information input by the user, and retrieves the corresponding measurement value group according to the query condition information to generate a measurement table.

[0013] The beneficial effects of the present invention are: not only can the six parameters of xyz displacement, xy angle tilt and rotation around the central axis of the object under test be measured simultaneously during the movement process, but also the detection efficiency, accuracy and stability of the voice coil motor motion stability can be effectively improved, and the volume of the system can be reduced and the cost can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which: Figure 1 It is a schematic diagram of a framework of a preferred embodiment of a six-dimensional motion parameter optical measurement system of the present invention; Figure 2 1 is a structural schematic diagram of a preferred embodiment of a six-dimensional motion parameter optical measurement system of the present invention; Figure 3 This is a schematic structural diagram of a Kohler illumination system in a six-dimensional motion parameter optical measurement system of the present invention; Figure 4 This is a schematic diagram of an XY displacement detection structure in a six-dimensional motion parameter optical measurement system of the present invention; Figure 5 This is a schematic diagram of the XY angle detection structure in a six-dimensional motion parameter optical measurement system of the present invention; Figure 6 This is a schematic diagram of a Z-direction displacement detection structure in a six-dimensional motion parameter optical measurement system of the present invention; Figure 7 It is a schematic diagram of the axial rotation detection structure in the six-dimensional motion parameter optical measurement system of the present invention. DETAILED DESCRIPTION

[0015] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0016] See also Figure 1-7 , embodiments of the present invention include: A six-dimensional motion parameter optical measurement system is used to synchronously detect the six-dimensional motion parameters of an object to be measured (voice coil motor). Its structure includes: a polarizer 17 with a semi-transparent and semi-reflective film coated on the upper surface, an XY displacement and center rotation measurement optical path lens, an XY tilt and Z displacement measurement optical path lens, and a detection controller. The polarizer is arranged above the object to be measured. The detection controller is respectively communicated with the XY displacement and center rotation measurement optical path lens, and the XY tilt and Z displacement measurement optical path lens, so as to use the XY displacement and center rotation measurement optical path lens to detect the displacement of the object to be measured in the XY axis direction and the rotation amount of the object to be measured around the central axis, and use the XY tilt and Z displacement measurement optical path lens to detect the angular tilt of the object to be measured in the XY axis direction and the displacement of the object to be measured in the Z axis direction.

[0017] More preferably, the polarizer is a circular structure with a diameter of 3 mm.

[0018] Among them, the detection controller can directly adopt the existing technology in this field, and this application does not involve improvements to the controller.

[0019] (1) XY displacement and center rotation measurement optical path lens The XY displacement and center rotation measurement optical path lens includes a set of displacement and rotation measurement optical path components, a third optical lens component 5, a first detector 6, a sixth optical lens component 7 and a fourth detector 8. The third measurement optical path component and the sixth measurement optical path component share a set of displacement and rotation measurement optical path components.

[0020] The displacement and rotation measurement optical path component includes a first illumination light source 1, a first optical lens component 2, a first light splitting element (light splitting prism 3 / graticule), and a second optical lens component 4.

[0021] The sixth optical lens assembly and the fourth detector are arranged in sequence from top to bottom below the object to be measured, and the fourth detector is on the focal plane of the sixth measurement optical path assembly. The second optical lens assembly, the third optical lens assembly and the first detector are arranged in sequence from bottom to top above the object to be measured, and the first detector is arranged on the focal plane of the optical system jointly formed by the second optical lens assembly and the third optical lens assembly. The first beam splitter prism is arranged obliquely between the second optical lens assembly and the third optical lens assembly, and the first illumination light source is coaxially arranged with the first optical lens assembly on one side of the first beam splitter prism.

[0022] The light beam emitted by the first illumination light source is reflected by the first optical lens assembly, the first beam splitter prism, and the second optical lens assembly in sequence to form an XY displacement detection optical path and a center rotation detection optical path. The XY displacement detection optical path passes through the object to be measured, the second optical lens assembly, the first beam splitter prism, and the third optical lens assembly and is imaged on the first detector. The center rotation detection optical path passes through the object to be measured and the sixth optical lens assembly and is imaged on the fourth detector.

[0023] Further preferably, the output light of the first illumination light source is linearly polarized light, and the polarization direction is the x direction.

[0024] Further preferably, the first illumination light source, the first optical lens assembly, and the second optical lens assembly constitute a Kohler illumination system, that is, the first illumination light source is located on the object plane of the first optical lens assembly, the aperture stop 19 is provided between the first beam splitting element and the first optical lens assembly and is located on the image plane of the first optical lens assembly, and the front focal plane of the second optical lens assembly coincides with the aperture stop, thereby ensuring that the energy distribution of the emitted light is uniform and is not affected by the energy distribution of the illumination light source. The principle diagram is shown in FIG. Figure 3 shown.

[0025] The first illumination light source can be a laser, specifically the Sorebo PL205 small laser module. The second illumination light source (laser) can be a custom fiber laser. The fourth optical lens assembly can be a 125mm focal length plano-convex lens sold by Nanyang Jingliang Optoelectronics. The fifth optical lens assembly can be a 250mm focal length biconvex lens sold by Nanyang Jingliang Optoelectronics. The sixth optical lens assembly can be a 50mm focal length plano-convex lens sold by Nanyang Jingliang Optoelectronics. The specific focal length can be determined based on the overall system volume.

[0026] The first, second, and third optical lens assemblies can also use existing lenses or lens groups, as long as the parameters of the lens or lens group match the measurement range, the size of the object being measured, and the detector size. For example, if the xy measurement range is 1mm, the object being measured is 5mm, and the detector size is 12mm, then the total magnification of the xy imaging system is 12 / (5+1)=2x. The object distance is the working distance of the instrument and must also be determined based on actual conditions. These factors are then used to design the optical system. The focal length parameters of the fourth and fifth optical lens assemblies can be selected based on the selected detector size of 9mm and the tilt measurement range of ±1°. If the z measurement range is ±1mm, the detector size, and the object being measured are 3mm, a system consisting of the fourth and fifth optical lens assemblies with a magnification of -2 is selected. Therefore, the focal length of the fifth optical lens assembly is twice the focal length of the fourth optical lens assembly.

[0027] Preferably, the first detector is a position sensitive device (2D PSD) or an area array camera. By measuring the voltage in two directions of the 2D PSD, the xy displacement parameters of the specific object being measured can be obtained. The area array camera can be the LBAS-U3250-14M model from Lingyun Optoelectronics.

[0028] Further preferably, the fourth detector is a light intensity sensor. When the special object to be measured rotates around the central axis, the energy incident on the fourth detector changes. The change in voltage of the light intensity sensor can be used to obtain the change in the object to be measured around the central axis.

[0029] Further preferably, the second lens assembly, the first beam splitter prism, and the third lens assembly form a double telecentric imaging optical system with a magnification of β1. When the special object to be measured moves a distance AB in the X-axis direction, the light spot on the first detector moves a distance A1B1, and satisfies the formula A1B1=AB×β1. Similarly, the moving distance of the special object to be measured in the Y-axis direction can be calculated. The principle is as follows: Figure 4 shown.

[0030] (2) XY tilt and Z displacement measurement optical path lens The XY-direction tilt and Z-direction displacement measurement optical path lens includes a set of tilt and displacement measurement optical path components, a second reflector 13 , a third detector 14 , a fifth optical lens assembly 15 , and a second detector 16 .

[0031] The tilt and displacement measurement optical path assembly includes a second illumination light source 9 , a first reflector 10 , a fourth optical lens assembly 11 , and a second beam splitter prism / graticule 12 .

[0032] The second illumination light source and the first reflector are arranged on one side of the second optical lens assembly and are located above the object to be measured. The fourth optical lens assembly, the fifth optical lens assembly, and the second detector are coaxially and obliquely arranged on the other side of the second optical lens assembly in sequence from bottom to top, and the second detector is located on the focal plane of the fifth optical lens assembly. The second beam splitter prism / graticule is arranged between the fourth optical lens assembly and the fifth optical lens assembly. The third detector is arranged on the side of the second beam splitter prism / graticule, and the second reflector is arranged between the second beam splitter prism / graticule and the third detector.

[0033] Further preferably, the inclination angle of the fourth optical lens assembly, the fifth optical lens assembly and the second detector is the same as the incident angle of the incident light; wherein the inclination angle can be 0-90° and most preferably 20-35°.

[0034] The first reflector changes the direction of the incident light, reducing the assembly accuracy of the second illumination light source, while the second reflector deflects the light beam to reduce the size of the instrument.

[0035] The light beam emitted by the second illumination light source is reflected in sequence by the first reflector, the object to be measured, and the fourth optical lens assembly to form a Z displacement detection optical path and an XY angle detection optical path. The Z displacement detection optical path passes through the second beam splitter prism / graticule and the fifth optical lens assembly and is incident on the second detector. The XY angle detection optical path passes through the second beam splitter prism / graticule and the second reflector and is incident on the third detector.

[0036] Further preferably, the output light of the second illumination light source is a collimated light beam with a diameter of 0.3 mm, and there is no requirement for its polarization state.

[0037] Further preferably, the third detector is a position sensitive device (two-dimensional PSD) or an area array camera, and the xy direction angle tilt parameters of the special object under test can be obtained by measuring the voltage in two directions of the two-dimensional PSD.

[0038] Further preferably, the second detector is a position sensitive device (one-dimensional PSD) or an area array camera, and the z-direction displacement parameter of the special object under test can be obtained by measuring the output voltage of the one-dimensional PSD.

[0039] A control method for a six-dimensional motion parameter optical measurement system, comprising the following steps: (1) Place the polarizer and the voice coil motor 18 in a test fixture, with the polarizer positioned on the voice coil motor to ensure that the polarizer can move along with the movement of the coil in the voice coil motor. After the voice coil motor is powered on, turn on the first and second illumination sources simultaneously.

[0040] (2) After the object to be tested is powered on, the XYZ direction position and the XY direction tilt position of the object to be tested are adjusted to the initial position, and the object to be tested and the polarizer are rotated around the center to the maximum position. At this time, the polarization direction of the polarizer is the same as the direction of the linearly polarized light, and the maximum light intensity I0 detected by the fourth detector at this time is obtained.

[0041] (3) Adjust the input current of the object under test according to the preset Z-axis movement distance threshold so that the object under test moves a predetermined distance along the z-axis direction.

[0042] Ideally, when current is increased, the VCM's x, y, angle, and rotation parameters remain unchanged, with only the z axis changing. However, due to errors or quality issues, the x, y axis may shift by 0.1 mm. Therefore, it is necessary to monitor these changes in x, y, angle, and rotation during this process to determine if the motor is qualified.

[0043] The Z-axis movement distance threshold includes a positive displacement threshold and a negative displacement threshold. When the position of the object to be measured in the Z-axis direction moves from the initial position to the positive displacement threshold, from the positive displacement threshold to the negative displacement threshold, and finally from the negative displacement threshold back to the initial position, it is a detection cycle.

[0044] In some embodiments of the present application, the initial position of the voice coil motor on the Z axis is 0, the positive displacement threshold is +1 mm, and the negative displacement threshold is -1 mm. When the voice coil motor moves from 0 to +1, then from +1 to -1, and then from -1 to 0, a detection cycle is formed.

[0045] (4) The linearly polarized light emitted by the first illumination light source passes through the first optical lens assembly, the first beam splitter prism and the second optical lens assembly to form an XY displacement detection light path and a center rotation detection light path, which are evenly irradiated on the surface of the special object to be measured coated with a semi-transparent and semi-reflective film.

[0046] (4.1) The XY displacement detection light path is reflected by the special object to be measured and then returns upward. The reflected light passes through the second optical lens assembly, the first beam splitter prism, and the third optical lens assembly before being imaged on the first detector (two-dimensional PSD). The detection controller obtains the real-time voltage values in two directions of the two-dimensional PSD at a preset frequency and calculates the XY displacement parameters of the special object to be measured based on the voltage values.

[0047] The frequency is actually determined by the response frequency of the detector and the data transmission rate. It can be designed as 1000 times per second, which is equivalent to outputting a set of data in 0.001s to reflect the changes in the object being measured.

[0048] (4.2) The central rotation detection light path is incident on the surface of the special object to be measured. Since the surface is coated with a semi-transparent and semi-reflective film, the transmitted light passes through the sixth optical lens assembly and is incident on the surface of the fourth detector (light intensity sensor). Detector 4 is a light intensity sensor. When the special object to be measured rotates around the central axis, the energy incident on the light intensity sensor changes. The detection controller obtains the voltage value of the light intensity sensor in real time and obtains the change of the object to be measured around the central axis based on the voltage change.

[0049] The linearly polarized light emitted by the first illumination light source (first laser) is evenly irradiated on the object to be measured after passing through the first optical lens assembly, the first beam splitter prism, and the second optical lens assembly. Part of the transmitted light is imaged on the fourth detector after passing through the sixth optical lens assembly. Since the object to be measured is a polarizer coated with a semi-transparent and semi-reflective film, after its axial position changes, the transmission intensity is related to the polarization direction of the incident light and the polarization direction of the polarizer, that is, I = I0cosθ of the object to be measured 2 Relationship, where I is the incident light intensity and θ is the angle between the polarization direction of the incident light and the polarization direction of the polarizer.

[0050] The light intensity sensor detects the rotation parameters of the object under test by detecting the intensity of the incident light. When starting the measurement, first fix the first laser and obtain the real-time light intensity value I detected by the light intensity sensor each time the object under test rotates. The rotation angle of the object under test changes .

[0051] (5) The small-diameter collimated light emitted by the second illumination light source is incident on the surface of the special object to be measured after being deflected by the first reflector. The reflected light passes through the fourth optical lens assembly and the second beam splitter prism to form the Z displacement detection optical path and the XY angle detection optical path.

[0052] (5.1) The XY angle detection light path passes through the second reflector and is incident on the third detector (two-dimensional PSD). The detection controller obtains the voltage values in two directions of the two-dimensional PSD in real time at a preset frequency and calculates the xy direction angle tilt parameter value of the special test object based on the voltage values.

[0053] XY angle measurement is based on the collimation principle. The collimated light emitted by the second illumination source is incident on the special object to be measured. The focal length of the fourth optical lens assembly is f, and the third detector is located on the back focal plane of the fourth optical lens assembly. When the special object to be measured is tilted at an angle a along the X-axis, the light spot on the third detector moves from A' to B', and satisfies the relationship A'B'=f×tan(2a). The same applies to the other direction. The principle diagram is shown in the figure below. Figure 6 shown.

[0054] (5.2) The Z-displacement detection light path passes through the fifth optical lens assembly and is incident on the second detector (one-dimensional PSD). The detection controller obtains the one-dimensional PSD output voltage in real time and obtains the Z-direction displacement parameters of the special test object based on the output voltage.

[0055] The Z-axis displacement measurement is based on the imaging principle. The angle between the emitted light direction of the second illumination light source (second laser) and the normal direction of the object to be measured is β. The Z-axis movement distance of the special object to be measured is z. The magnification of the optical system composed of the fifth optical lens assembly and the fourth optical lens assembly is β2. The movement distance of the light spot on the detector is A1'B1'. Therefore, its Z-axis displacement z = A1'B1'×β2×cosβ / sin(2β).

[0056] (6) The detection controller generates and saves a measurement value group at a preset frequency, wherein a measurement value group includes a real-time displacement value in the x-direction, a real-time displacement value in the y-direction, a real-time angle value of the central axis rotation, a real-time tilt value of the x-direction angle, a real-time tilt value of the y-direction angle, and a real-time displacement parameter in the z-direction corresponding to the current generation time.

[0057] (7) The detection controller obtains the query condition information input by the user, and retrieves the corresponding measurement value group according to the query condition information to generate a measurement table for use in judging the quality of the voice coil motor.

[0058] The beneficial effects of the six-dimensional motion parameter optical measurement system of the present invention are: 1. It can simultaneously measure six parameters of the object under test during motion: xyz displacement, xy angle tilt, and rotation around the central axis, effectively improving the detection efficiency of voice coil motor motion stability; 2. The use of Köhler illumination solves the problem of measurement value changes caused by temperature rise, avoids measurement errors caused by the energy distribution of the light source itself, and avoids displacement measurement errors caused by the tilt of the object in traditional imaging methods, thereby improving measurement accuracy and stability. 3. Provides non-contact measurement without causing damage to the voice coil motor.

[0059] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A six-dimensional motion parameter optical measurement system, characterized in that: include: A polarizer with a semi-transparent and semi-reflective film on its upper surface, an optical lens for measuring XY displacement and center rotation, an optical lens for measuring XY tilt and Z displacement, and a detection controller. The polarizer is arranged above the object to be measured. The detection controller is respectively connected to the optical lens for measuring XY displacement and center rotation, and the optical lens for measuring XY tilt and Z displacement. The XY-axis displacement and center rotation measurement optical path lens includes a group of displacement and rotation measurement optical path components, a third optical lens component, a first detector, a sixth optical lens component and a fourth detector. The displacement and rotation measurement optical path component includes a first illumination light source, a first optical lens component, an aperture stop, a first spectrometer, a second optical lens component, the sixth optical lens component and the fourth detector are sequentially arranged from top to bottom below the object to be measured, and the fourth detector is on the focal plane of the sixth measurement optical path component. The second optical lens component, the third optical lens component and the first detector are sequentially arranged from bottom to top above the polarizer, and the first detector is arranged on the focal plane of the optical system composed of the second optical lens component and the third optical lens component. A beam splitter is obliquely disposed between the second optical lens assembly and the third optical lens assembly; an aperture stop is disposed between the first beam splitter and the first optical lens assembly and is located on the image plane of the first optical lens assembly; a first illumination light source is coaxially disposed with the first optical lens assembly on one side of the first beam splitter, so that linearly polarized light emitted by the first illumination light source sequentially passes through the first optical lens assembly, the first beam splitter, and the second optical lens assembly to form an XY displacement detection optical path and a center rotation detection optical path; the XY displacement detection optical path passes through the object to be measured, the second optical lens assembly, the first beam splitter prism, and the third optical lens assembly, and is imaged on the first detector; the center rotation detection optical path passes through the object to be measured and the sixth optical lens assembly, and is imaged on the fourth detector; The XY-direction tilt and Z-direction displacement measurement optical path lens includes a group of tilt and displacement measurement optical path components, a second reflector, a third detector, a fifth optical lens component, and a second detector. The tilt and displacement measurement optical path component includes a second illumination light source, a first reflector, a fourth optical lens component, and a second spectrometer. The second illumination light source and the first reflector are arranged on one side of the second optical lens component and above the polarizer. The fourth optical lens component, the fifth optical lens component, and the second detector are coaxially and tilted from bottom to top on the other side of the second optical lens component, and the second detector is located in the fifth optical lens component. On the focal plane of the component, the second beam splitter is arranged between the fourth optical lens assembly and the fifth optical lens assembly, the third detector is arranged on the side of the second beam splitter, and the second reflector is arranged between the second beam splitter and the third detector, so that the light beam emitted by the second illumination light source is reflected by the first reflector, the object to be measured and the fourth optical lens assembly in sequence to form a Z displacement detection light path and an XY angle detection light path, the Z displacement detection light path passes through the second beam splitter and the fifth optical lens assembly and is incident on the second detector, and the XY angle detection light path passes through the second beam splitter and the second reflector and is incident on the third detector.

2. A six-dimensional motion parameter optical measurement system according to claim 1, characterized in that: The spectroscopic element includes a spectroscopic prism or a graticule.

3. The six-dimensional motion parameter optical measurement system according to claim 1, characterized in that: The light emitted by the first illumination light source is linearly polarized light with the polarization direction being in the x direction, and the light emitted by the second illumination light source is a collimated light beam.

4. The six-dimensional motion parameter optical measurement system according to claim 1, characterized in that: The first illumination light source, the first optical lens assembly, and the second optical lens assembly constitute a Kohler illumination system. The first illumination light source is located on the object plane of the first optical lens assembly, and the front focal plane of the second optical lens assembly coincides with the aperture stop.

5. The six-dimensional motion parameter optical measurement system according to claim 1, characterized in that: The first detector and the third detector are two-dimensional PSDs or area array cameras, the second detector is a one-dimensional PSD or area array camera, and the fourth detector is a light intensity sensor.

6. The six-dimensional motion parameter optical measurement system according to claim 1, characterized in that: The second lens assembly, the first beam splitter prism and the third lens assembly constitute a double telecentric imaging optical system.

7. The six-dimensional motion parameter optical measurement system according to claim 1, characterized in that: The inclination angles of the fourth optical lens assembly, the fifth optical lens assembly and the second detector are the same as the incident angle of the incident light; preferably, the inclination angle is 20-35°.

8. A control method for a six-dimensional motion parameter optical measurement system, characterized in that the steps include: (1) First, fix the polarizer on the object to be measured so that the polarizer moves with the movement of the object to be measured, and turn on the first and second illumination sources at the same time; (2) After the object to be tested is powered on, the XYZ direction position and the XY tilt position of the object to be tested are adjusted to the initial position, and the object to be tested and the polarizer are rotated around the center to the maximum position. At this time, the polarization direction of the polarizer is the same as the direction of the linearly polarized light, and the maximum light intensity I0 detected by the fourth detector is obtained; (3) adjusting the input current of the object to be tested according to a preset Z-axis movement distance threshold, so that the object to be tested moves a predetermined distance along the Z-axis direction; wherein the Z-axis movement distance threshold includes a positive displacement threshold and a negative displacement threshold. When the position of the object to be tested in the Z-axis direction moves from the initial position to the positive displacement threshold, from the positive displacement threshold to the negative displacement threshold, and finally from the negative displacement threshold back to the initial position, a detection cycle is formed; (4) When the object to be tested and the polarizer are moving, the XY displacement and center rotation measurement optical path lens is used to detect the displacement of the object to be tested in the XY axis direction and the rotation amount of the object to be tested around the center axis, and the XY tilt and Z displacement measurement optical path lens is used to detect the angular tilt of the object to be tested in the XY axis direction and the displacement in the Z axis direction; (4.1) The linearly polarized light emitted by the first illumination light source passes through the first optical lens assembly, the first beam splitter prism, and the second optical lens assembly to form an XY displacement detection optical path and a center rotation detection optical path, which are uniformly illuminated on the surface of the polarizer coated with a semi-transparent and semi-reflective film; (4.1.1) The XY displacement detection light path is reflected by the polarizer and then returns upward. The reflected light passes through the second optical lens assembly, the first beam splitter prism, and the third optical lens assembly before being imaged on the first detector. The detection controller obtains the real-time detection value of the first detector at a preset detection frequency and calculates the x- and y-axis displacement values of the object under test based on the real-time detection value of the first detector; (4.1.2) The central rotation detection light path is incident on the surface of the polarizer, and the transmitted light is incident on the surface of the fourth detector through the sixth optical lens assembly. The detection controller obtains the real-time detection value of the fourth detector at a preset detection frequency, and obtains the angle value of the object under test rotating about the central axis based on the real-time detection value of the fourth detector; (4.2) The small-diameter collimated light emitted by the second illumination source is deflected by the first reflector and incident on the surface of the polarizer. The reflected light passes through the fourth optical lens assembly and the second beam splitter prism to form the Z displacement detection optical path and the XY angle detection optical path; (4.2.1) The XY angle detection light path passes through the second reflector and is incident on the third detector. The detection controller obtains the real-time detection value of the third detector at a detection frequency preset by the detection controller, and the inclination value of the object under test in the x-axis and y-axis directions is obtained based on the real-time detection value of the third detector; (4.2.2) The Z-displacement detection light path passes through the fifth optical lens assembly and is incident on the second detector. The detection controller obtains the real-time detection value of the second detector at a detection frequency preset by the detection controller, and the Z-direction displacement value of the object to be measured is obtained based on the real-time detection value of the second detector; (5) The detection controller generates and saves a measurement value group at a preset frequency, wherein a measurement value group includes a real-time displacement value in the x-direction, a real-time displacement value in the y-direction, a real-time angle value of the central axis rotation, a real-time tilt value of the x-direction angle, a real-time tilt value of the y-direction angle, and a real-time displacement parameter value in the z-direction corresponding to the current generation time.

9. The control method of a six-dimensional motion parameter optical measurement system according to claim 1, characterized in that: In step (4), (a) Given the magnification of the bi-telecentric imaging optical system as β1 and the distance the object moves in the x-axis direction as AB, the real-time x-direction displacement detected by the first detector is A1B1 = AB × β1. Similarly, the y-direction displacement detected by the first detector is calculated. (b) When the object to be tested and the polarizer are moving, all the real-time light intensity values I detected by the fourth detector during the detection period are obtained to calculate the real-time angle value of the object to be tested rotating around the central axis in real time. ; (c) Obtain the focal length f of the fourth optical lens assembly and the movement distance A'B' detected by the third detector. The real-time tilt angle of the object under test along the X-axis is a = arctan(A'B' / f) / 2. Similarly, the tilt angle of the object under test along the Y-axis is calculated. (d) Obtain the angle β between the direction of the emitted light of the second illumination light source and the normal of the object to be measured, the magnification β2 of the optical system composed of the fifth optical lens assembly and the fourth optical lens assembly, and the movement distance A1'B1' detected by the second detector. The real-time movement distance z of the object to be measured along the Z-axis is = A1'B1' × β2 × cosβ / sin(2β).

10. The control method of a six-dimensional motion parameter optical measurement system according to claim 1, characterized in that: In step (5), the detection controller obtains the query condition information input by the user, and retrieves the corresponding measurement value group according to the query condition information to generate a measurement table.

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