Crystal comprehensive detection device and method based on multi-information fusion

Abstract

The invention discloses a comprehensive crystal detection device and method based on multi-information fusion, and the method comprises the steps: arranging three collimation lasers in an array manner, employing an optical measurement method similar to an optical lever, and obtaining a light spot position image through the shooting of a light spot imaging visual camera; the pose information of the optical element on the optical element positioning tool can be obtained through accurate inversion; the optical axis direction of the to-be-detected crystal is accurately determined by overlooking the change of two parallel straight lines of the cross wire image recorded by the visual camera, and the method is extremely simple and effective, so that the crystal can be effectively prevented from being loaded into a crystal frame in a wrong direction, the subsequent assembly process is effectively prevented from being carried out on the basis of errors, and the production efficiency is improved. Waste of manpower and material resources is avoided; moreover, by adopting the comprehensive crystal detection device and the comprehensive crystal detection method, electric automatic control can be realized very easily, so that automatic crystal detection is realized, and the detection efficiency is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical element detection, in particular to a crystal comprehensive detection device and method based on multi-information fusion. BACKGROUND

[0002] In a frequency-doubling laser system, frequency-doubling crystals such as second-harmonic generation crystals and third-harmonic generation crystals are needed. Before being assembled into a frame, the frequency-doubling crystals need to be detected and judged for the direction of the optical axis to ensure that the requirements of the corresponding terminal after assembly are met. At present, the traditional method is to use manual method to check the processing marks on the side of the crystal to determine the direction of the optical axis of the crystal during the assembly of the crystal. However, if the marks are wrong, the conversion of the frequency-doubled light cannot be realized, the correct adjustment of the detuning angle caused by temperature change cannot be realized, and the subsequent assembly process is also based on the wrong foundation, resulting in waste of manpower and material resources.

[0003] In addition, the frequency-doubling crystals are horizontally delivered with packaging boxes. Since the frequency-doubling crystals are in the coverless packaging boxes, there are error sources such as placement gap, motion angle error, mechanical part long cantilever stress deformation, etc. Therefore, referring to Figure 13 , the spatial pose of the frequency-doubling crystal and the tooling relative to the ideal position usually has a certain deviation, which is often a comprehensive effect of angle deviation and height deviation. Therefore, in order to realize the accurate grabbing of the optical element, the pose of the optical element must be detected. However, since the optical element is in the packaging box, the lateral field of view is blocked by the side of the packaging box, and other mechanical parts occupy part of the space during the assembly process, so that the pose of the optical element is difficult to be directly observed by using the existing method.

[0004] It is urgent to solve the above problems. SUMMARY

[0005] Therefore, the present application provides a crystal comprehensive detection device and method based on multi-information fusion.

[0006] The technical scheme is as follows:

[0007] The first aspect of this application relates to a crystal integrated testing device based on multi-information fusion, comprising a testing platform, wherein a device mounting recess is formed in the middle of the platform surface, an optical element positioning fixture is arranged around the device mounting recess on the platform surface, a turntable support plate is installed in the middle of the device mounting recess, an electric turntable and a crosshair imaging assembly are respectively installed on the upper and lower sides of the turntable support plate, a standard crystal positioning fixture that can rotate under its drive is installed on the top of the electric turntable, the turntable support plate and the electric turntable form a vertically extending image transmission channel, the standard crystal positioning fixture and the crosshair imaging assembly are respectively located at the upper and lower ends of the image transmission channel, and a top-view vision camera is installed on the testing platform by a heightening bracket, the lens of the top-view vision camera facing downwards towards the standard crystal positioning fixture;

[0008] The platform is provided with a module bracket and a screen bracket located on both sides of the optical element positioning fixture. A pose detection module is installed on the top of the module bracket, and an imaging screen facing the pose detection module is vertically installed on the top of the screen bracket. The pose detection module includes a module housing fixedly installed on the top of the module bracket, a spot imaging vision camera and three collimating lasers all mounted on the module housing. The lens of the spot imaging vision camera faces the imaging screen. The three collimating lasers can emit three parallel laser beams obliquely downward toward the optical element positioning fixture. Two of the collimating lasers are symmetrically distributed on both sides of the spot imaging vision camera in the horizontal direction, and the other collimating laser is located above or below the spot imaging vision camera.

[0009] The second aspect of this application relates to a crystal synthesis detection method based on multi-information fusion, employing the aforementioned crystal synthesis detection device, comprising:

[0010] S1. Position and install the standard crystal with the known optical axis direction on the standard crystal positioning fixture according to the selected direction;

[0011] S2. Position and install the crystal to be tested on the optical component positioning fixture;

[0012] S3. Perform pose detection on the crystal under test and make online adjustments;

[0013] S4. Detect the optical axis direction of the crystal under test.

[0014] The above-mentioned crystal comprehensive detection device and method based on multi-information fusion has achieved the following technical effects:

[0015] 1. By arranging three collimated lasers in an array and employing an optical measurement method similar to an optical lever, when there is a height deviation in the optical element, the positions of the three light spots change simultaneously and equally on the imaging screen. When there is an angular deviation in the optical element, the spacing between the light spots on the imaging screen changes. The amount of change is related to the laser incident angle, the beam spacing distance, and the element deflection angle. Therefore, the image of the light spot position obtained by the light spot imaging vision camera can accurately invert the pose information of the optical element located on the optical element positioning fixture, thereby bypassing the lateral field of view to achieve accurate online detection of the vertical in-plane angle and height information of the optical element, and thus enabling accurate grasping of the optical element.

[0016] 2. The optical axis direction of the crystal under test can be accurately determined by the change of two parallel straight lines in the crosshair image recorded by the top-view vision camera. The method is extremely simple and effective, which can effectively avoid the crystal being installed in the crystal frame with the wrong orientation, and thus effectively avoid the subsequent assembly process being carried out on the basis of the error, avoiding the waste of manpower and material resources.

[0017] 3. By using this crystal integrated testing device and method, electrical automation control can be easily achieved, thereby realizing automated testing and greatly improving testing efficiency. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the crystal integrated testing device from one perspective.

[0019] Figure 2 This is a schematic diagram of the crystal integrated testing device from another perspective.

[0020] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0021] Figure 4 A schematic diagram showing the working relationship between the electric turntable, the turntable support plate, and the crosshair imaging assembly;

[0022] Figure 5 for Figure 4 A sectional view;

[0023] Figure 6 This is a schematic diagram of the crosshair imaging component.

[0024] Figure 7 This is a schematic diagram illustrating the principle of optical axis orientation detection for the crystal under test.

[0025] Figure 8 The optical path diagram of the crosshair natural light emitted from the crosshair imaging component passing through a standard crystal;

[0026] Figure 9When the standard crystal and the crystal under test are both positive or both negative crystals and have the same optical axis direction, the crosshair natural light emitted from the crosshair imaging component passes through the standard crystal and the crystal under test in sequence.

[0027] Figure 10 When the standard crystal and the crystal under test are both positive or both negative crystals and their optical axes are opposite, the optical path diagram of the crosshair natural light emitted from the crosshair imaging component passing through the standard crystal and the crystal under test in sequence.

[0028] Figure 11 This is a photograph taken by a top-down vision camera, showing the image through a standard crystal.

[0029] Figure 12 A photograph taken by a top-down vision camera, showing the crystal under test.

[0030] Figure 13 This is a schematic diagram of the pose deviation of optical components;

[0031] Figure 14 This is a schematic diagram illustrating the principle of pose detection for the crystal under test.

[0032] Figure 15 This is a schematic diagram illustrating how the imaging results change with deviation.

[0033] Figure 16 This is a schematic diagram of the biaxial tilt angle of a crystal;

[0034] Figure 17 This is a schematic diagram illustrating the effect of the light spot on the imaging screen.

[0035] Figure 18 This is a schematic diagram showing the effect of the light spot on the imaging screen after the crystal is leveled.

[0036] Figure 19 For characteristic quantity The fitting trend plot;

[0037] Figure 20 For characteristic quantity The fitting trend plot;

[0038] Figure 21 Measured values ​​and characteristic quantities The fitting trend plot. Detailed Implementation

[0039] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0040] like Figures 1-7 as well as Figure 14As shown, a crystal comprehensive testing device based on multi-information fusion includes a testing stage 1. The middle of the table surface 1a of the testing stage 1 is recessed to form a device mounting recess 1b. An optical element positioning fixture 2 is arranged on the table surface 1a around the device mounting recess 1b. The optical element positioning fixture 2 is used to position the crystal 17 to be tested. A turntable plate 7 is installed in the middle of the device mounting recess 1b.

[0041] Please see Figure 1 as well as Figures 4-6 An electric turntable 8 and a crosshair imaging assembly are respectively installed on the upper and lower sides of the turntable plate 7. A standard crystal positioning fixture 10, which can rotate under its drive, is installed on the top of the electric turntable 8. The standard crystal positioning fixture 10 is used to position the standard crystal 16. The turntable plate 7 and the electric turntable 8 form a vertically extending image transmission channel 13. The standard crystal positioning fixture 10 and the crosshair imaging assembly are located at the upper and lower ends of the image transmission channel 13, respectively. A top-view vision camera 15 is installed on the detection table 1 through a heightening bracket 14. The lens of the top-view vision camera 15 is facing downwards towards the standard crystal positioning fixture 10.

[0042] Therefore, the image transmission channel 13 is located directly above the crosshair image imaging assembly, the standard crystal 16 is located directly above the image transmission channel 13, the crystal under test 17 is located directly above the standard crystal 16, and the top-view vision camera 15 is located directly above the crystal under test 17. The crosshair image is used to generate crosshair natural light on the standard crystal 16 and the crystal under test 17.

[0043] Please see Figure 5 and Figure 6 The crosshair imaging assembly of this embodiment includes a common mounting bracket 9 fixedly installed at the bottom of the turntable support plate 7. A mask plate 11 and a surface light source 12 located directly below the mask plate 11 are mounted on the common mounting bracket 9. A crosshair slit 11a with a cross structure is formed on the mask plate 11, directly opposite the standard crystal positioning fixture 10. That is, the crosshair slit 11a is directly opposite the standard crystal 16 on the standard crystal positioning fixture 10. Therefore, the crosshair natural light emitted from the surface light source 12 passes through the crosshair slit 11a and sequentially generates a crosshair image on the standard crystal 16 and the crystal under test 17.

[0044] Please see Figure 4 and Figure 5The electric turntable 8 includes a turntable base 8a, a hollow turntable 8b, and a rotation drive assembly 8c. The turntable base 8a is fixedly mounted on the turntable support plate 7, the hollow turntable 8b is rotatably mounted on the turntable base 8a, and the rotation drive assembly 8c is mounted on the turntable base 8a and used to drive the hollow turntable 8b to rotate. In this embodiment, the rotation drive assembly 8c includes a rotation drive motor and a reduction mechanism. The rotation drive motor drives the hollow turntable 8b to rotate along the turntable base 8a through the reduction mechanism. Simultaneously, the hollow turntable 8b has a vertically penetrating turntable through-hole 8b1, and the turntable support plate 7 has a support plate through-hole 7a communicating with the turntable through-hole 8b1. The turntable through-hole 8b1 and the support plate through-hole 7a together form the image transmission channel 13. Light emitted from the surface light source 12 passes through the crosshair slit 11a and then through the image transmission channel 13 to the standard crystal 16.

[0045] In this embodiment, the standard crystal positioning fixture 10 includes a crystal fixing stage 10a fixedly installed on the top of the hollow turntable 8b and a crystal cover 10b detachably fitted onto the top of the crystal fixing stage 10a. Both the crystal fixing stage 10a and the crystal cover 10b are annular structures and together form a crystal clamping cavity 10c adapted to the standard crystal. Therefore, the standard crystal 16 can be clamped and fixed in the crystal clamping cavity 10c by the crystal fixing stage 10a and the crystal cover 10b. The crystal clamping cavity 10c is connected to the top of the image transmission channel 13. Since the crystal cover 10b is detachable, the standard crystal 16 can be replaced and installed in the crystal clamping cavity 10c, thereby enabling the appropriate standard crystal 16 to be selected adaptively according to the crystal 17 to be tested, improving the versatility of the entire device.

[0046] Please see Figure 2 and Figure 3 The testing table 1a is provided with module brackets 3 and screen brackets 4 located on both sides of the optical element positioning fixture 2.

[0047] The module bracket 3 has a pose detection module 5 installed on its top, and the screen bracket 4 has an imaging screen 6 installed vertically on its top, facing the pose detection module 5.

[0048] In this embodiment, the pose detection module 5 includes a module housing 5a fixedly installed on the top of the module bracket 3, a spot imaging vision camera 5b and three collimating lasers 5c all installed on the module housing 5a. The lens of the spot imaging vision camera 5b faces the imaging screen 6. The three parallel collimating lasers 5c are distributed in an isosceles triangle around the spot imaging vision camera 5b. Two of the collimating lasers 5c are symmetrically distributed on both sides of the spot imaging vision camera 5b in the horizontal direction, and the other collimating laser 5c is located above or below the lens facing the imaging screen 6.

[0049] Three collimating lasers 5c can emit three parallel laser beams at an angle downward toward the optical element positioning fixture 2; the test crystal 17 located on the optical element positioning fixture 2 can reflect the three laser beams toward the imaging screen 6, thereby forming three light spots on the imaging screen 6; the light spot imaging vision camera 5b can record the three light spots on the imaging screen 6.

[0050] Therefore, please see Figure 14 and Figure 15 By arranging three collimated lasers 5c in an array and employing an optical measurement method similar to an optical lever, when the crystal under test 17 has a height deviation, the positions of the three laser spots change simultaneously and equally on the imaging screen 6. When the crystal under test 17 has an angular deviation, the spacing between the laser spots on the imaging screen 6 changes. The amount of change is related to the laser incident angle, the beam spacing distance, and the element deflection angle. Therefore, the position image of the laser spot obtained by the laser spot imaging vision camera 5b can accurately invert the pose information of the crystal under test 17 located on the optical element positioning fixture 2.

[0051] Example 2:

[0052] A crystal comprehensive detection method based on multi-information fusion, employing the crystal comprehensive detection device of Example 1, includes:

[0053] S1. Position the standard crystal 16 with the known optical axis direction on the standard crystal positioning fixture 10 according to the selected direction.

[0054] S2. Position and install the crystal to be tested 17 on the optical element positioning fixture 2.

[0055] S3. Perform pose detection on the crystal 17 under test and make online adjustments.

[0056] S4. Detect the optical axis direction of the crystal 17 to be tested.

[0057] Please see Figure 14 and Figure 15 Step S3 is performed according to the following steps:

[0058] S31. Three collimated lasers 5c emit three parallel laser beams toward the crystal under test 17 located on the optical element positioning fixture 2. The three laser beams are reflected by the upper surface of the crystal under test 17 and form three light spots on the imaging screen 6. The light spot imaging vision camera 5b takes a picture of the imaging screen 6 to obtain the light spot position image.

[0059] S32. Based on the spot position image, the pose information of the crystal 17 to be tested located on the optical element positioning fixture 2 is obtained by inversion.

[0060] Specifically, step S32 includes:

[0061] Establish a mathematical model for the location of the light spot.

[0062] To calculate the impact of spot pose on imaging results, the imaging results of a single spot are first analyzed.

[0063] The upper surface of the crystal 17 under test is the reflective surface. The world coordinate system is defined as follows: the shooting direction facing the light spot imaging vision camera 5b is the Z-axis direction, the horizontal direction perpendicular to the Z-axis direction is the X-axis direction, and the vertical downward direction is the Y-axis direction.

[0064] The plane equation of the reflecting surface of the crystal 17 to be tested is set as follows:

[0065] ;

[0066] In the above formula, A, B, C, and D are all planar parameters.

[0067] Set the emission point position of the laser beam from one of the collimating lasers 5c. The incident beam equation of the laser beam is then expressed as:

[0068] ;

[0069] In the above formula, Let be the three-dimensional vector of the coordinates of a point on the laser beam of collimated laser 5c in the world coordinate system; assume that the laser beam emitted by collimated laser 5c is parallel to the principal beam surface and has an incident angle relative to the horizontal plane of . Then the beam direction vector ; To describe the relationship between this point on the laser beam and A scalar of distance.

[0070] The upper surface of the crystal 17 under test is a reflecting surface, and the angle is used. and angle For the biaxial tilt angle of the reflecting surface, please refer to [link / reference]. Figure 16 ,horn In the XOY plane of the world coordinate system, the angle between the line of intersection of the reflecting surfaces and the X-axis is given. Figure 16 The angle shown The direction is negative, the angle Let be the angle between the line of intersection of the reflecting surface and the Z-axis in the YOZ plane of the world coordinate system. Figure 16 The angle shown If the direction is positive, then the expression for the corresponding reflection surface normal vector n is:

[0071] ;

[0072] The height deviation h of the crystal 17 under test is defined as the point at the bottom of the world coordinate system through which the reflecting surface passes. Then the plane parameters can be obtained:

[0073] ;

[0074] The position of the reflection point can be obtained by using the equation of the incident beam and the equation of the plane of the reflecting surface. :

[0075] ;

[0076] According to the vector form of the law of reflection, the unit vector of the reflected laser beam is obtained as follows:

[0077] ;

[0078] Based on the location of the reflection point and the unit vector of the emitted beam Establish the equation for the emitted beam:

[0079] ;

[0080] In the above formula, To describe the three-dimensional vector of the coordinates of a point on the incident beam in the world coordinate system, To describe the relationship between this point on the laser beam and A scalar of distance;

[0081] Assuming that imaging screen 6 coincides with the YOZ plane of the world coordinate system, the plane equation of imaging screen 6 is: Its normal vector The plane equation of the imaging screen 6 is set as follows: Then the plane parameters Thus, the coordinates of the light spot are obtained. for:

[0082] ;

[0083] As can be seen from the above derivation, any point on the incident laser beam of the collimated laser 5c will not affect the position of the laser spot. To simplify the calculation, we assume that the emission point of the laser beam of the collimated laser 5c is located at... If the light spot is located in the XOY plane of the world coordinate system, then the coordinates of the light spot are... for:

[0084] ;

[0085] In the above formula, parameters A, B, and C are all determined by the biaxial tilt angle of the reflecting surface of the crystal 17 under test relative to the horizontal plane (i.e., angle). and angle The value of h is determined by the angle deviation, which reflects the influence of the angle deviation. h is the height deviation of the crystal 17 under test. Under the condition that other system parameters are determined, the imaging result is only affected by the above deviation.

[0086] Furthermore, to simplify the calculation, the incident angle of the laser beam of the collimated laser 5c relative to the horizontal plane is designed to be 45°.

[0087] The two collimated lasers 5c, symmetrically distributed horizontally on both sides of the spot imaging visual camera 5b, form two light spots on the imaging screen 6, which are represented as spot 1 and spot 3, respectively. The remaining light spot is represented as spot 2. Please refer to [link to relevant documentation]. Figure 17 The difference between the mean Y-coordinate of spot 1 and spot 3 in the world coordinate system and the Y-coordinate of spot 2 in the world coordinate system is expressed as a characteristic quantity. The difference between the Y-coordinates of spot 1 and spot 3 in the world coordinate system is expressed as a characteristic quantity. The mean value of the Y-coordinates of spot 1, spot 2, and spot 3 in the world coordinate system is expressed as a characteristic quantity. .

[0088] The imaging process for the three light spots is the same, the only difference being the initial position of each collimating laser 5c. The imaging results are as follows: Figure 17 As shown, the imaging screen 6 coincides with the XOZ plane of the world coordinate system. Therefore, the emission point coordinates of the laser beams of the collimated laser 5c corresponding to spots 1, 2, and 3 are respectively:

[0089] ;

[0090] Therefore, the following correspondence exists:

[0091] ;

[0092] Feature quantities were identified from the image of the light spot location. Measured values, characteristic quantities Measured values ​​and characteristic quantities The measured values ​​are as follows. The algorithm for accurately identifying the coordinates of the three light spots on the imaging screen 6 based on vision is very mature and is common knowledge to those skilled in the art, so it will not be elaborated here.

[0093] Feature quantities are established based on the mathematical model of the light spot position. Mathematical models and characteristic quantities Mathematical model and characteristic quantity The mathematical model.

[0094] Feature quantity The mathematical model is as follows:

[0095] ;

[0096] Feature quantity The mathematical model is as follows:

[0097] ;

[0098] Feature quantity The mathematical model is as follows:

[0099] ;

[0100] feature quantity Measured values, characteristic quantities Measured values, characteristic quantities Substituting the measured values, the emission point coordinates of the three collimated lasers 5c, and the incident angles relative to the horizontal plane into the characteristic quantity... Mathematical models and characteristic quantities Mathematical model and characteristic quantity The mathematical model was used to solve the problem and obtain the biaxial tilt angle of the crystal 17 under test.

[0101] Specifically, feature quantity , characteristic quantity , characteristic quantity And the emission point coordinates of the three collimated lasers 5c , , and the angle of incidence relative to the horizontal plane All values ​​are known; substitute them. Mathematical models and characteristic quantities Mathematical model and characteristic quantity In the mathematical model, parameters A, B, and C can be solved because:

[0102] ;

[0103] Substituting parameters A, B, and C into the above equation, the biaxial tilt angle of the crystal 17 under test can be obtained: angle and angle .

[0104] Please see Figure 18 Based on the obtained dual-axis tilt angle, the crystal 17 to be tested on the optical element positioning fixture 2 is leveled.

[0105] The average Y-coordinate of spot 1, spot 2, and spot 3 after leveling the crystal 17 under test is expressed as a characteristic quantity. And the feature quantity is identified from the spot position image. The measured value of this feature quantity The height deviation h of the crystal 17 under test is equal to this height deviation h. Then, the height of the crystal 17 under test on the optical element positioning fixture 2 is adjusted according to this height deviation h.

[0106] Similarly, feature quantities are identified from the image of the light spot location. The measured values ​​are as follows. The algorithm for accurately identifying the coordinates of the three light spots on the imaging screen 6 based on vision is very mature and is common knowledge to those skilled in the art, so it will not be elaborated here.

[0107] The theoretical accuracy analysis of the pose detection device and method based on array-type laser reflection focal spot monitoring is given below:

[0108] With other parameters remaining constant, its characteristic quantity with horns Relationship such as Figure 19 As shown, characteristic quantity with horns Relationship such as Figure 20 As shown, the calculation results were obtained by linear fitting, which is considered to reflect the trend of change relatively well.

[0109] The inherent errors of the 5b spot-image vision camera, the spot center localization error, and the camera calibration error, after optical path magnification, result in errors in the spot center coordinates obtained in the world coordinate system. This error directly affects the pose calculation. Assuming a deviation of 0.5 pixels in a single direction of the image coordinate system, after magnification, with the 5b spot-image vision camera's working distance of 800mm, the corresponding error in the real world is approximately 0.04mm. The transfer coefficient corresponding to the fitted slope is approximately 0.77° / mm, which corresponds to an angle measurement error of approximately 0.031°. The corresponding transfer coefficient is approximately 0.28° / mm, resulting in an angle measurement error of approximately 0.011°. The cost of decoupling angle and height is a sharp decrease in the transfer coefficient of the Y-axis angle, thus amplifying the measurement error. The ratio of their transfer coefficients is approximately 2.76, which is close to the ratio of the standard deviations of the errors in the actual measurement results.

[0110] Feature quantity The relationship between it and its height deviation h is as follows Figure 21 As shown, the two exhibit a completely linear relationship, with a corresponding measurement error of approximately 0.02 mm. Since the angle deviation is calculated first after decoupling the angle deviation and height deviation, the height deviation will be affected by the angle deviation.

[0111] It should be noted that the slope in the above measurements is obtained when other values ​​are zero. For example, the mean Y-coordinate of the light spot changes with the height deviation, and only when the plane is completely parallel to the ideal plane does it have exactly a twofold relationship. When the element has a tilt angle, its coefficient will change very little.

[0112] For step S1, if the crosshair imaging component is activated, please refer to... Figure 8 The optical axis of the standard crystal is shown in the figure. After the crosshairs of natural light pass through the first face of the standard crystal 16, they are split into beams with mutually perpendicular polarization directions. If the standard crystal 16 is a negative crystal, meaning the e-ray travels faster than the o-ray, then according to Huygens' principle, the wavefronts of the formed o-ray and e-ray are as follows... Figure 8 As shown, the lines connecting the point of incidence of natural light on the first face of the standard crystal 16 with the points of tangency between the tangents of the o-ray and e-ray wavefronts within the standard crystal 16 represent the o-ray and e-ray rays propagating within the standard crystal 16. The o-ray follows the law of refraction; since it is incident perpendicularly, the o-ray continues to exit along a direction perpendicular to the second face of the standard crystal 16. The e-ray exits to the right. The pattern formed by the crosshairs of natural light after passing through the standard crystal 16 is shown in the image. Figure 8 As shown, one of the lines splits into two lines, creating a birefringence phenomenon.

[0113] Step S4 is performed according to the following steps:

[0114] S41. The crosshair image imaging component is activated, and the top-view vision camera 15 records the crosshair image that appears on the crystal under test 17, consisting of two parallel lines and a line perpendicular to both.

[0115] S42. The electric turntable 8 drives the standard crystal 16 to rotate until the optical axis direction of the crystal under test 17 is determined by the change of two parallel straight lines in the crosshair image recorded by the top-view vision camera 15.

[0116] When the test crystal 17 and the standard crystal 16 are both positive crystals or both negative crystals:

[0117] If the standard crystal 16 stops rotating when the distance between the two parallel straight lines of the crosshair image is at its maximum, then the optical axis direction of the crystal under test 17 is the same as that of the standard crystal 16.

[0118] Specifically, please see Figure 9In the diagram, both the standard crystal 16 and the crystal under test 17 are negative crystals. When the standard crystal 16 is rotated to a certain angle, the two parallel straight lines of the crosshair image are most separated. At this time, the optical axis of the crystal under test 17 is parallel to the optical axis of the standard crystal 16. Principle analysis: The o-ray and e-ray rays emerging from the second surface of the standard crystal 16 enter the first surface of the crystal under test 17 and remain o-ray and e-ray rays. According to Huygens' principle, the wavefronts of the formed o-ray and e-ray rays are as follows... Figure 9 As shown, the e-ray propagates faster. The lines connecting the incident points of the o-ray and e-ray rays from the second surface of the standard crystal 16 at the first surface of the crystal under test 17, and the points of tangency between the tangents of the o-ray and e-ray wavefronts within the crystal under test 17, represent the o-ray and e-ray rays propagating within the crystal under test 17. The o-ray follows the law of refraction; since it is incident perpendicularly, it continues to exit along a direction perpendicular to the second surface of the crystal under test 17. The e-ray ray's incident point at the first surface of the crystal under test is slightly to the right. The e-ray ray obtained by the above connection propagates further to the right within the crystal under test 17, finally exiting at the second surface of the crystal under test 17, where it is further separated from the o-ray ray. Therefore, it can be seen that... Figure 9 The pattern on the right shows that, compared to the crosshair image seen through the standard crystal 16, the two parallel straight lines are further apart. Based on this method and the observed phenomenon, it can be determined that the optical axis direction of the test crystal 17 is parallel (the same) to the optical axis direction of the standard crystal 16.

[0119] If the standard crystal 16 stops rotating when the two parallel straight lines of the crosshair image coincide, the optical axis of the crystal under test 17 is opposite to that of the standard crystal 16.

[0120] Specifically, please see Figure 10 In the diagram, both the standard crystal 16 and the crystal under test 17 are negative crystals. When the standard crystal 16 is rotated to a certain angle, the two parallel straight lines of the crosshair image merge into a single line. At this time, the optical axis of the crystal under test 17 is mirror-symmetrical (opposite) to the optical axis of the standard crystal 16. Principle analysis: The o-ray and e-ray rays exiting from the second surface of the standard crystal 16 enter the first surface of the crystal under test 17 and remain o-ray and e-ray rays. According to Huygens' principle, the wavefronts of the formed o-ray and e-ray rays are as follows... Figure 10As shown, the e-ray propagates faster. The lines connecting the incident points of the o-ray and e-ray rays from the second surface of the standard crystal 16 at the first surface of the crystal under test 17, and the points of tangency between the tangents of the o-ray and e-ray wavefronts within the crystal under test 16, represent the o-ray and e-ray rays propagating within the crystal under test 17. The o-ray follows the law of refraction; since it is incident perpendicularly, it continues to exit in a direction perpendicular to the second surface of the crystal under test 17. The e-ray ray, incident at the first surface of the crystal under test 17, is slightly to the right. The e-ray ray obtained by the above connection propagates slightly to the left within the crystal under test 17, finally exiting at the second surface of the crystal under test 17, coinciding with the o-ray ray. Therefore, it can be seen that... Figure 10 The pattern on the right shows that the crosshairs seen through the standard crystal 16 are not separated; instead, two parallel straight lines become a single vertical line. Based on this method and the observed phenomenon, it can be determined that the optical axis of the test crystal 17 is mirror-symmetrical (opposite) to the optical axis of the standard crystal 16.

[0121] Similarly, when the crystal under test 17 and the standard crystal 16 are positive and negative crystals, or negative and positive crystals respectively: if the standard crystal 16 is controlled to stop rotating when the two parallel straight lines of the crosshair image coincide, then the optical axis direction of the crystal under test 17 is the same as that of the standard crystal 16; if the standard crystal 16 is controlled to stop rotating when the distance between the two parallel straight lines of the crosshair image is at its maximum, then the optical axis direction of the crystal under test 17 is opposite to that of the standard crystal 16.

[0122] Based on the above method, the actual pattern for optical axis detection of the crystal 17 under test is as follows: Figure 11 and Figure 12 As shown, Figure 9 The phenomenon observed through a standard crystal 16 is that the crosshair image exhibits birefringence and overlap. Figure 10 To make the phenomenon visible through the test crystal 17, the two parallel straight lines of the crosshair image are further separated, and the optical axis of the test crystal 17 is parallel to the optical axis of the standard crystal 16.

[0123] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention. Those skilled in the art, under the guidance of the present invention, can make various similar representations without departing from the spirit and claims of the present invention, and such modifications all fall within the protection scope of the present invention.

Claims

1. A crystal integrated testing device based on multi-information fusion, comprising a testing stage, wherein a device mounting recess is formed in the center of the stage surface, and an optical element positioning fixture arranged around the device mounting recess is disposed on the stage surface, characterized in that, A turntable support plate is installed in the middle of the equipment mounting recess. An electric turntable and a crosshair imaging assembly are installed on the upper and lower sides of the turntable support plate, respectively. A standard crystal positioning fixture that can rotate under its drive is installed on the top of the electric turntable. The turntable support plate and the electric turntable form a vertically extending image transmission channel. The standard crystal positioning fixture and the crosshair imaging assembly are located at the upper and lower ends of the image transmission channel, respectively. A top-view vision camera is installed on the detection table through a heightening bracket. The lens of the top-view vision camera is facing downwards and directly towards the standard crystal positioning fixture. The platform is provided with a module bracket and a screen bracket located on both sides of the optical element positioning fixture. A pose detection module is installed on the top of the module bracket, and an imaging screen facing the pose detection module is vertically installed on the top of the screen bracket. The pose detection module includes a module housing fixedly installed on the top of the module bracket, a spot imaging vision camera and three collimating lasers all mounted on the module housing. The lens of the spot imaging vision camera faces the imaging screen. The three collimating lasers can emit three parallel laser beams obliquely downward toward the optical element positioning fixture. Two of the collimating lasers are symmetrically distributed on both sides of the spot imaging vision camera in the horizontal direction, and the other collimating laser is located above or below the spot imaging vision camera.

2. The crystal comprehensive testing device according to claim 1, characterized in that, The crosshair imaging assembly includes a common mounting bracket fixedly installed at the bottom of the turntable support plate. A mask plate and a surface light source located directly below the mask plate are mounted on the common mounting bracket. The mask plate has a crosshair slit in a cross structure at the position facing the standard crystal positioning fixture.

3. The crystal comprehensive testing device according to claim 2, characterized in that, The electric turntable includes a turntable base fixedly mounted on a turntable support plate, a hollow turntable rotatably mounted on the turntable base, and a rotation drive assembly for driving the hollow turntable to rotate. The hollow turntable has a vertical through-hole, and the turntable support plate has a support plate through-hole communicating with the turntable through-hole. The turntable through-hole and the support plate through-hole together constitute the image transmission channel.

4. The crystal comprehensive testing device according to claim 3, characterized in that, The standard crystal positioning fixture includes a crystal fixing stage fixedly installed on the top of the hollow turntable and a crystal cover that can be detachably fitted onto the top of the crystal fixing stage. Both the crystal fixing stage and the crystal cover are annular structures and together form a crystal clamping cavity adapted to the standard crystal. The crystal clamping cavity is connected to the top of the image transmission channel.

5. A comprehensive crystal detection method based on multi-information fusion, characterized in that, The crystal comprehensive testing device according to any one of claims 1-4 comprises: S1. Position and install the standard crystal with the known optical axis direction on the standard crystal positioning fixture according to the selected direction; S2. Position and install the crystal to be tested on the optical component positioning fixture; S3. Perform pose detection on the crystal under test and make online adjustments; S4. Detect the optical axis direction of the crystal under test.

6. The crystal comprehensive detection method according to claim 5, characterized in that, Step S3 is performed according to the following steps: S31. Three collimated lasers emit three parallel laser beams toward a crystal located on an optical element positioning fixture. The three laser beams are reflected by the upper surface of the crystal and form three light spots on the imaging screen. The light spot imaging vision camera takes a picture of the imaging screen to obtain an image of the light spot position. S32. Based on the spot position image, the pose information of the crystal located on the optical element positioning fixture is obtained by inversion.

7. The crystal comprehensive detection method according to claim 6, characterized in that, Step S32 is performed according to the following steps: S321. Establish a mathematical model for the position of the light spot; S322. The two collimated lasers symmetrically distributed on both sides of the spot imaging vision camera along the horizontal direction form two spots on the imaging screen, which are represented as spot 1 and spot 3, respectively. The remaining spot is represented as spot 2. The difference between the average Y-coordinate of spot 1 and spot 3 in the world coordinate system and the Y-coordinate of spot 2 in the world coordinate system is represented as a characteristic quantity. The difference between the Y-coordinates of spot 1 and spot 3 in the world coordinate system is expressed as a characteristic quantity. The mean value of the Y-coordinates of spot 1, spot 2, and spot 3 in the world coordinate system is expressed as a characteristic quantity. ; S323. Identify feature quantities from the light spot position image. Measured values, characteristic quantities Measured values ​​and characteristic quantities The measured value; S324. Establish feature quantities based on the mathematical model of the light spot position. Mathematical models and characteristic quantities Mathematical model and characteristic quantity Mathematical model; S325, Feature quantities Measured values, characteristic quantities Measured values, characteristic quantities Substituting the measured values, the emission point coordinates of the three collimated lasers, and the incident angles relative to the horizontal plane into the characteristic values... Mathematical models and characteristic quantities Mathematical model and characteristic quantity The mathematical model was solved to obtain the biaxial tilt angle of the optical element; S326. Based on the dual-axis tilt angle obtained in step S325, level the optical element on the optical element positioning fixture. S327. The average Y-coordinate of spot 1, spot 2, and spot 3 after the optical element is leveled is expressed as a characteristic quantity. And the feature quantity is identified from the spot position image. The measured value of this feature quantity Equal to the height deviation h of the optical element; S328. Based on the height deviation h obtained in S327, adjust the height of the optical element on the optical element positioning fixture.

8. The crystal comprehensive detection method according to claim 7, characterized in that, Step S321 includes: The upper surface of the optical element is the reflecting surface. The plane equation of the reflecting surface of the optical element is defined as follows: ； In the above formula, A, B, C, and D are all planar parameters; Set the emission point position of the laser beam from one of the collimated lasers. The incident beam equation of the laser beam is then expressed as: ； In the above formula, Let be the three-dimensional vector of the coordinates of a point on the laser beam of the collimated laser in the world coordinate system; assume that the laser beam emitted by the collimated laser is parallel to the principal plane and has an incident angle relative to the horizontal plane of . Then the beam direction vector ; To describe the relationship between this point on the laser beam and A scalar of distance; Use angle and angle Let the biaxial tilt angle of the reflecting surface represent the angle of inclination. Then, the expression for the corresponding normal vector n of the reflecting surface is: ； The height deviation h of the optical element is defined as the distance from the reflecting surface to the lower point in the world coordinate system. Then the plane parameters can be obtained: ； Since any point on the incident laser beam of a collimated laser will not affect the position of the laser spot, it is assumed that the emission point of the collimated laser beam is located at... If the light spot is located in the XOY plane of the world coordinate system, then the coordinates of the light spot are: ； In the above formula, parameters A, B, and C are all determined by the biaxial tilt angle of the reflecting surface of the optical element relative to the horizontal plane. In step S322, the coordinates of the emission points of the laser beams of the collimated lasers corresponding to light spots 1, 2, and 3 are as follows: ； Therefore, the following correspondence exists: ； In step S324, the feature quantity The mathematical model is as follows: ； Feature quantity The mathematical model is as follows: ； Feature quantity The mathematical model is as follows: 。 9. The crystal comprehensive detection method according to claim 5, characterized in that, Step S4 is performed according to the following steps: S41. The crosshair imaging component is activated, and the top-view vision camera records the crosshair image that appears on the crystal under test, consisting of two parallel lines and a line perpendicular to both. S42. The electric turntable drives the standard crystal to rotate until the optical axis direction of the crystal under test is determined by the change of two parallel straight lines in the crosshair image recorded by the top-view vision camera.

10. The crystal comprehensive detection method according to claim 9, characterized in that, Step S4 is performed according to the following steps: In step S42, when the crystal to be tested and the standard crystal are both positive or both negative: if the standard crystal is controlled to stop rotating when the two parallel straight lines of the crosshair image coincide, the optical axis direction of the crystal to be tested is opposite to that of the standard crystal; if the standard crystal is controlled to stop rotating when the distance between the two parallel straight lines of the crosshair image is at its maximum, the optical axis direction of the crystal to be tested is the same as that of the standard crystal. When the crystal under test and the standard crystal are respectively a positive crystal and a negative crystal, or a negative crystal and a positive crystal: if the standard crystal is controlled to stop rotating when the two parallel straight lines of the crosshair image coincide, then the optical axis direction of the crystal under test is the same as that of the standard crystal; if the standard crystal is controlled to stop rotating when the distance between the two parallel straight lines of the crosshair image is the largest, then the optical axis direction of the crystal under test is opposite to that of the standard crystal.

Images