A method, apparatus and optical device for determining the diopter of a tunable optical device

Abstract

The application provides a method and device for determining the diopter of a tunable optical device and the optical device, comprising: performing interference removal processing on an initial point cloud subset of a polymer layer to obtain a target point cloud subset; determining a center region warping amount of an effective polymer layer region based on the target point cloud subset; and determining the diopter of the tunable optical device according to the center region warping amount. Thus, due to the elastic deformation of the polymer layer caused by the change of the driving voltage, the curvature radius of the polymer layer and the diopter will change. After the elastic deformation of the polymer layer, the three-dimensional point cloud data of the film layer is analyzed to obtain the center region warping amount of the effective polymer layer region, and finally the diopter is calculated according to the center region warping amount and a mapping function. The whole process can be realized by only one three-dimensional topography measuring device, the measurement cost is low, the diopter of all tunable optical devices can be measured, and the overall quality of the tunable optical device is ensured.

Description

Technical Field

[0001] This invention relates to the field of MEMS tunable optical device detection technology, and in particular to a method, apparatus and tunable optical device for determining the refractive power of a tunable optical device. Background Technology

[0002] Micro-Electro-Mechanical Systems (MEMS) are miniaturized intelligent systems that integrate micro-mechanical structures, microelectronic circuits, and micro-sensors. MEMS control mechanical actions with electrical signals or convert mechanical actions into electrical signals to achieve specific functions (such as driving or optical control). Based on these advantages, MEMS can be applied to tunable optical devices to form MEMS tunable optical devices, thus achieving the desired functions. For example, MEMS tunable optical devices are MEMS devices used in tunable lenses (TLens).

[0003] Diopter is a core performance indicator of MEMS tunable optics. If the diopter does not meet design requirements, it will seriously affect the focusing accuracy of the MEMS tunable optics, and consequently affect the imaging quality of the camera module. Therefore, it is necessary to measure the diopter of MEMS tunable optics to prevent unqualified products from entering downstream applications.

[0004] In related technologies, it is necessary to rely on dedicated interferometers or wavefront sensors to measure the refractive power of MEMS tunable optics, but dedicated interferometers and wavefront sensors are expensive. Some small and medium-sized manufacturers will send a certain number of tunable optics to third-party institutions for random inspection. This makes it impossible to achieve full inspection during mass production, and it is easy to miss defective products.

[0005] Therefore, there is an urgent need for a new method for measuring refractive power to reduce measurement costs, improve the detection rate of MEMS tunable optics, and thus ensure the quality of MEMS tunable optics. Summary of the Invention

[0006] To address the problems existing in the prior art, embodiments of the present invention provide a method, apparatus, and tunable optical device for determining the refractive power of a tunable optical device, thereby solving or partially solving the technical problem in the prior art where the measurement cost for measuring the refractive power of MEMS tunable optical devices is high and full inspection cannot be achieved, thus failing to ensure the overall quality of the tunable optical device.

[0007] A first aspect of the present invention provides a method for determining the refractive power of a tunable optical device, the tunable optical device comprising a polymer layer; the method comprising: The three-dimensional point cloud data of the polymer layer is preprocessed to obtain an initial point cloud subset of the effective polymer layer region; the three-dimensional point cloud data of the polymer layer is obtained by scanning the polymer layer when a target driving voltage is applied to the tunable optical device and the target driving voltage remains stable. The initial point cloud subset of the effective polymer layer region is processed to remove interference using a preset fitting algorithm to obtain the target point cloud subset; The warpage of the center region of the effective polymer layer region is determined based on the target point cloud subset. The refractive power of the tunable optics is determined based on the central region warpage of the effective polymer layer region and a mapping function between the pre-constructed polymer layer refractive power and the central region warpage.

[0008] In the above scheme, the preprocessing of the three-dimensional point cloud data of the polymer layer to obtain an initial subset of point clouds for the effective polymer layer region includes: The three-dimensional point cloud data of the polymer layer is filtered to obtain the target three-dimensional point cloud dataset. Extract the planar coordinates of the 3D point cloud data of each target to obtain a planar point set; The first edge point of the planar point set is determined based on the edge detection algorithm; Determine whether the initial region enclosed by the first edge point is the target shape. If so, obtain the height data of the target 3D point cloud data within the initial region, and determine the height variance of the target 3D point cloud data within the initial region based on the height data. If the height variance of the target 3D point cloud data within the initial region is less than a preset threshold, then the second edge point of the initial region is extracted. Traverse the second edge point of the initial region. If the second edge point is determined to be a mutation point, delete the mutation point from the initial region to obtain the initial point cloud subset of the effective polymer layer region.

[0009] In the above scheme, determining whether the initial region enclosed by the first edge points is the target shape includes: The first edge point is fitted using a circular fitting algorithm to obtain the center and radius of the fitted circle; For each first edge point, determine the distance between the first edge point and the center of the circle, and determine the deviation between the distance and the radius; Determine the root mean square value of all deviations. If the root mean square value is less than a preset deviation threshold, determine the initial region as the target shape.

[0010] In the above scheme, determining the second edge point as a mutation point includes: For each second edge point, determine the height difference between the second edge point and a preset number of neighboring points, and determine the average value of the height difference; If the average value is greater than a preset height threshold, then the second edge point is determined to be the mutation point.

[0011] In the above scheme, the step of using a preset fitting algorithm to perform interference removal processing on the initial point cloud subset of the effective polymer layer region to obtain the target point cloud subset includes: For each point in the initial point cloud subset of the effective polymer layer region, coordinate normalization is performed to obtain the normalized polar coordinates of each point; A linear equation for each point is constructed using Zernikal polynomial basis functions and normalized polar coordinates for each point; the linear equation includes the Zernikal polynomial for each point and the fitting residual. With the goal of minimizing the sum of squared residuals of all points, the coefficients of the Zernike polynomial are obtained by solving the linear equation system using the least squares method. Substituting the coefficients of the Zernike polynomial into the linear equation for each point yields the fitting height for each point; For any current point in the initial point cloud subset, the corresponding residual is determined based on the fitted height and actual height of each current point. If the residual is greater than a preset residual threshold, the current point is determined to be a distortion point. The distorted points in the initial point cloud subset are deleted to obtain the remaining points; the fitted height of the remaining points is remapped to the original coordinate system to obtain the target point cloud subset.

[0012] In the above scheme, determining the warpage of the central region of the effective polymer layer region based on the subset of the target point cloud includes: Determine the central region of the effective polymer layer region, and extract a reference point cloud subset of the central region from the target point cloud subset; Obtain the height of the center point of the reference point cloud subset, and determine the average height of the third edge point in the reference point cloud subset; The warping amount of the central region is determined based on the height of the center point and the average height.

[0013] In the above scheme, before determining the refractive power of the tunable optics based on the warpage of the center region of the effective polymer layer region and the mapping function between the pre-constructed polymer layer refractive power and the warpage of the center region, the method further includes: Get N The refractive power corresponding to the standard polymer layer; Regarding the N Measurements were performed on a set of standard polymer layers to obtain... NThe warpage amount in the central region corresponding to the standard polymer layer of the group; Regarding the N The refractive power corresponding to the standard polymer layer and the N The warpage of the central region corresponding to the standard polymer layer is fitted to obtain the mapping function between the refractive power of the polymer layer and the warpage of the central region.

[0014] In the above scheme, determining the refractive power of the tunable optics based on the warpage of the central region of the effective polymer layer region includes: According to the formula Determine the refractive power of the tunable optics. D ;in, The b As a correction amount, the The warpage amount is the amount of warpage in the center region of the effective polymer layer region.

[0015] A second aspect of the present invention provides an apparatus for determining the refractive power of a tunable optical device, the tunable optical device comprising a polymer layer; the apparatus comprising: The first processing unit is used to preprocess the three-dimensional point cloud data of the polymer layer to obtain an initial point cloud subset of the effective polymer layer region; the three-dimensional point cloud data of the polymer layer is obtained by scanning the polymer layer when a target driving voltage is applied to the tunable optical device and the target driving voltage remains stable. The second processing unit is used to perform interference removal processing on the initial point cloud subset of the effective polymer layer region using a preset fitting algorithm to obtain the target point cloud subset. The first determining unit is used to determine the warpage amount of the center region of the effective polymer layer region based on the target point cloud subset. The second determining unit is used to determine the refractive power of the tunable optics based on the warpage of the center region of the effective polymer layer region and a mapping function between the pre-constructed polymer layer refractive power and the warpage of the center region.

[0016] A third aspect of the present invention provides a tunable optical device comprising: A glass support layer is used to provide foundation support; A polymer layer is located above the glass support layer; A glass thin film layer is located above the polymer layer; A piezoelectric thin film is located on the glass thin film layer and also above the polymer layer, and the piezoelectric thin film is deposited on the microelectromechanical actuator wafer; Gold bumps are located at the four corners of the microelectromechanical actuator wafer; wherein, An external voltage signal is transmitted to the piezoelectric film through the gold bumps. The piezoelectric film converts the voltage signal into a driving force, which drives the polymer layer to deform and change its curvature.

[0017] This invention provides a method, apparatus, and tunable optical device for determining the refractive power of a tunable optical device, the tunable optical device comprising a polymer layer; the method includes: preprocessing three-dimensional point cloud data of the polymer layer to obtain an initial point cloud subset of an effective polymer layer region; the three-dimensional point cloud data of the polymer layer is obtained by scanning the polymer layer while a target driving voltage is applied to the tunable optical device and the target driving voltage remains stable; performing interference removal processing on the initial point cloud subset of the effective polymer layer region using a preset fitting algorithm to obtain a target point cloud subset; determining the warpage of the central region of the effective polymer layer region based on the target point cloud subset; and determining the warpage of the central region of the effective polymer layer region based on the warpage of the central region. The diopter of the tunable optics is determined by measuring the diopter. Since changes in the driving voltage cause elastic deformation of the polymer layer, the radius of curvature of the polymer layer also changes, resulting in a change in diopter. Therefore, this invention can pre-construct a mapping function between the diopter of the polymer layer and the warp amount in the central region. After the polymer layer undergoes elastic deformation, the three-dimensional point cloud data of the film layer is analyzed to obtain the warp amount in the central region of the effective polymer layer area. Finally, the diopter is calculated based on the warp amount in the central region and the mapping function. The entire process only requires a three-dimensional topography measurement device, resulting in low measurement costs. Therefore, diopter measurement of all tunable optics can be achieved throughout the mass production process, ensuring the overall quality of the tunable optics. Attached Figure Description

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram of the overall structure of an adjustable focus lens TLens according to an embodiment of the present invention is shown; Figure 2 A schematic diagram of the overall structure of a voltage-free adjustable focus lens TLens according to an embodiment of the present invention is shown. Figure 3 A schematic diagram of the overall structure of an adjustable focusing lens TLens driven by a 30V voltage according to an embodiment of the present invention is shown. Figure 4 A schematic flowchart of a method for determining the refractive power of a tunable optical device according to an embodiment of the present invention is shown; Figure 5 A schematic diagram of the central region of an effective polymer layer region according to an embodiment of the present invention is shown; Figure 6 A schematic diagram of a device for determining the refractive power of a tunable optical device according to an embodiment of the present invention is shown. Detailed Implementation

[0019] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0020] To better understand the technical solution of this invention, we will first introduce tunable optical devices. These tunable optical devices are MEMS tunable optical devices, taking a tunable lens (TLens) as an example. Figures 1 to 3 As shown, the MEMS tunable optical device includes: Glass support layer 1 is used to provide basic support; Polymer layer 2 is located above glass support layer 1; Glass film layer 3 is located above polymer layer 2; The piezoelectric thin film 4 is located on the glass thin film layer 3 and also above the polymer layer 2. The piezoelectric thin film 4 is deposited on the microelectromechanical actuator wafer 5. Gold bumps 6 are located at the four corners of the microelectromechanical actuator wafer 5; among them, An external voltage signal is transmitted to the microelectromechanical actuator wafer 5 through the gold bump 6. The microelectromechanical actuator wafer 5 converts the voltage signal into a driving force, which drives the polymer layer 2 in the cavity to deform and change its curvature.

[0021] Specifically, the glass support layer 1 is located at the bottom layer (light-transmitting side) of the entire TLens device. As the substrate of the optical path, the glass support layer 1 ensures that light passes smoothly through the TLens device. The surface of the glass support layer 1 is coated with an anti-reflection coating to reduce light reflection loss and improve optical transmission efficiency.

[0022] An annular rigid bushing is also provided on the glass support layer 1. The bushing is made of optically inert silicon or glass ceramic material. The inner diameter of the bushing matches the effective optical aperture of the lens, and the outer diameter of the bushing is consistent with the edge contour of the glass support layer 1. The annular rigid bushing serves as a connection medium and mechanical support between the polymer layer 2 and the glass support layer 1.

[0023] Polymer layer 2 is located above the annular rigid bushing. Polymer layer 2 is the core optical deformation component of the TLens device. Polymer layer 2 can undergo elastic deformation under the action of driving force, changing its curvature.

[0024] A microelectromechanical actuator (MEMS) wafer 5 is disposed above the polymer layer 2. A piezoelectric thin film 4 is deposited on the surface of the MEMS wafer 5. The MEMS wafer 5 is a silicon-based driving wafer fabricated using MEMS technology. The MEMS wafer 5 has a ring-shaped hollow structure to allow the piezoelectric thin film 4 to generate a piezoelectric effect when energized, efficiently transmitting stress and driving the thin film layer to bend. This causes deformation of the polymer layer 2, changing its curvature and achieving zooming, thus adjusting the lens focal length. The piezoelectric thin film 4 can convert the voltage signal transmitted by the gold bumps 6 into a driving force, causing deformation of the polymer layer 2.

[0025] The gold bumps 6 are located at the four corners of the MEMS actuator wafer 5 and are electrical connection structures for TLens devices, used to transmit external drive voltage signals to the MEMS actuator wafer 5.

[0026] refer to Figure 2 , Figure 2 In the 0V state, no electrical signal is transmitted to the microelectromechanical actuator wafer 5, the piezoelectric thin film 4 is stress-free, the glass thin film layer 3 remains flat, the polymer layer 2 is planar, and the lens focal length is fixed.

[0027] refer to Figure 3 When a 30V electrical signal is transmitted to the microelectromechanical actuator wafer 5, the piezoelectric film 4 generates mechanical stress under the action of voltage, pulling the glass film layer 3 downward and squeezing the polymer layer 2, so that the lens surface forms a spherical curvature, changing the focal length to achieve zoom.

[0028] Because changes in the driving voltage cause elastic deformation of polymer layer 2, the radius of curvature of polymer layer 2 also changes, thus altering the refractive power. Theoretically, based on an ideal sphere, the refractive power... D and radius of curvature R Satisfying formula (1): (1) In formula (1), n This is the theoretical refractive index.

[0029] The radius of curvature and diopter satisfy formula (2): (2) In formula (2), L For membrane diameter, This represents the warpage amount in the center region of the effective polymer layer area.

[0030] It can be seen that there is an indirect relationship between refractive power and the warping of the central region of the effective polymer layer area, and refractive power can be indirectly measured by the amount of warping.

[0031] However, the above formula is based on an ideal sphere. In practical applications, when polymer layer 2 undergoes elastic deformation, the resulting surface may not be an ideal sphere. Therefore, directly using the above formula to measure refractive power will result in a significant error. Therefore, in actual measurements, this invention uses multiple sets of polymer layers with known refractive powers and central region warpage to fit the refractive power and central region warpage, obtaining a mapping function between the polymer layer's refractive power and the central region warpage. During actual measurements, this mapping function is used to measure the refractive power of the polymer layer.

[0032] Therefore, based on this, the present invention provides a method for determining the refractive power of a tunable optical device, such as... Figure 4 As shown, the method includes the following steps: S410, the three-dimensional point cloud data of the polymer layer is preprocessed to obtain an initial point cloud subset of the effective polymer layer region; the three-dimensional point cloud data of the polymer layer is obtained by scanning the polymer layer when a target driving voltage is applied to the tunable optical device and the target driving voltage remains stable.

[0033] A target driving voltage is applied to the tunable optics. Once the target driving voltage stabilizes, the polymer layer will undergo stable elastic deformation. The polymer layer of the tunable optics is then scanned using a 3D laser scanning machine to obtain 3D point cloud data of the polymer layer. Since the obtained 3D point cloud data may contain abnormal noise caused by environmental interference, preprocessing is required to improve the accuracy of the 3D point cloud data of the polymer layer, resulting in an initial subset of point clouds representing the effective polymer layer region.

[0034] In one embodiment, the three-dimensional point cloud data of the polymer layer is preprocessed to obtain an initial subset of point clouds for the effective polymer layer region, including: The 3D point cloud data of the polymer layer is filtered to obtain the target 3D point cloud dataset. Extract the planar coordinates of the 3D point cloud data of each target to obtain a planar point set; The first edge point of the planar point set is determined based on the edge detection algorithm; Determine whether the initial region enclosed by the first edge point is the target shape. If so, obtain the height data of the target 3D point cloud data within the initial region, and determine the height variance of the target 3D point cloud data within the initial region based on the height data. If the height variance of the target 3D point cloud data within the initial region is less than a preset threshold, then the second edge point of the initial region is extracted. Traverse the second edge point of the initial region. If the second edge point is determined to be a mutation point, delete the mutation point from the initial region to obtain the initial point cloud subset of the effective polymer layer region.

[0035] Specifically, a Gaussian filter can be used to filter the 3D point cloud data to obtain the target 3D point cloud dataset. In the target 3D point cloud dataset, each target 3D point cloud data point has unique coordinates (…). x , y , z (), x , y () represents the planar coordinates of the target 3D point cloud data. z The height coordinates of the target 3D point cloud data.

[0036] Extract the planar coordinates of each target's 3D point cloud data to obtain a planar point set. Traverse this planar point set, and for any traversed current point, calculate the distance between the current point and its surrounding points. k One (e.g.) k =3) The average distance between neighboring points. If the average distance between neighboring points is greater than a preset distance threshold, then the current point is a first edge point. After traversing the planar point set, all first edge points can be obtained.

[0037] Theoretically, the effective polymer layer region should be circular in shape; therefore, it is necessary to determine whether the initial region enclosed by the first edge points is the target shape (circular). In one embodiment, determining whether the initial region enclosed by the first edge points is the target shape includes: The first edge point is fitted using a circular fitting algorithm to obtain the center and radius of the fitted circle; For each first edge point, determine the distance between the first edge point and the center of the circle, and determine the deviation between the distance and the radius; Determine the root mean square value of all deviations. If the root mean square value is less than the preset deviation threshold, determine the initial region as the target shape.

[0038] The circle fitting algorithm can be the least squares method. After fitting the first edge point using the least squares method, the center and radius of the fitted circle can be obtained.

[0039] Traverse the first edge points. For each first edge point, determine the distance between the first edge point and the center of the circle, and then determine the deviation (difference) between the distance and the radius. Calculate the root mean square value of all deviations. If the root mean square value is less than the preset deviation threshold, then the shape of the initial region enclosed by the first edge points is determined to be close to a circle.

[0040] The height variation in the effective polymer layer region should be continuous. Therefore, it is necessary to further determine whether the height variation of the target 3D point cloud data in the initial region is continuous. Specifically, the height data of the target 3D point cloud data in the initial region can be obtained, and the height variance of the target 3D point cloud data in the initial region can be determined based on the height data. If the height variance of the target 3D point cloud data in the initial region is less than a preset threshold, it indicates that the height variation of the target 3D point cloud data in the initial region is continuous, and the initial region is a valid region.

[0041] In the initial region, there may also be point cloud data of supporting structures (such as supporting frames, gold bumps). In order to more accurately determine the effective polymer layer region, it is also necessary to extract the second edge point of the initial region, determine whether the second edge point is a mutation point, and if so, delete the mutation point from the initial region to obtain the initial point cloud subset of the effective polymer layer region.

[0042] In one implementation, determining the second edge point as a mutation point includes: For each second edge point, determine the height difference between the second edge point and a preset number of neighboring points, and determine the average value of the height difference; If the average height difference is greater than the preset height threshold, then the second edge point is determined as a mutation point.

[0043] After the above preprocessing, an initial point cloud subset of the effective polymer layer region can be obtained.

[0044] S411, the initial point cloud subset of the effective polymer layer region is subjected to interference removal processing using a preset fitting algorithm to obtain the target point cloud subset.

[0045] To further reduce the impact of edge support structures on membrane deformation, thereby minimizing interference from edge support structures in warpage measurement and improving the accuracy of warpage measurement, a pre-defined fitting algorithm is needed to deduce the target point cloud subset from the initial point cloud of the effective polymer layer region. The fitting algorithm can be the Zernike polynomial fitting algorithm or other suitable fitting algorithms; no restriction is placed here.

[0046] In one implementation, a preset fitting algorithm is used to perform noise reduction processing on an initial subset of the point cloud in the effective polymer layer region to obtain a target subset of the point cloud, including: For each point in the initial point cloud subset of the effective polymer layer region, the coordinates are normalized to obtain the normalized polar coordinates of each point. A linear equation for each point is constructed using Zernikal polynomial basis functions and normalized polar coordinates for each point; the linear equation contains the Zernikal polynomial for each point and the fitting residual. With the goal of minimizing the sum of squared residuals of all points, the least squares method is used to solve the linear equation system to obtain the coefficients of the Zernike polynomials. Substituting the coefficients of the Zernike polynomial into the linear equation for each point yields the fitting height for each point; For any current point in the initial cloud subset, determine the corresponding residual based on the fitted height and actual height of each current point. If the residual is greater than the preset residual threshold, then the current point is determined to be a distortion point. The distorted points in the initial point cloud subset are deleted to obtain the remaining points; the fitted heights of the remaining points are remapped to the original coordinate system to obtain the target point cloud subset.

[0047] Specifically, the planar coordinates of each point can be determined according to formula (3). x , y Normalize the data to obtain the normalized radial distance for each point. : (3) In formula (3), The x-coordinate of the center of the effective film region is given. The ordinate of the center of the effective film region is given. R The radius of the effective film region.

[0048] The polar angle of each point is determined according to formula (4). : (4) The form of Zernike polynomial basis functions , m For angular steps, n For radial order, lower-order basis functions correspond to the basic deformation of the film. In this invention, a 6th-order Zernike polynomial basis function is selected to fit the spherical deformation of the film. The 6th-order Zernike polynomial basis functions are shown in Table 1. Table 1

[0049] For each point in the initial point cloud subset of the effective polymer layer region i Each of these constructs a corresponding system of linear equations: (5) In formula (5), , , , , , All are coefficients of Zernike polynomials. For the first i Normalized radial distance of points, For the first i The polar angle of each point For the first i The residual at each point For the first i The fitting height of each point.

[0050] With the objective of minimizing the sum of squared residuals at all points, the least squares method is used to solve all linear equations to obtain the coefficients of the Zernike polynomials.

[0051] Substituting the coefficients into the linear equations corresponding to each point yields the fitting height for each point.

[0052] Because the presence of edge support causes the actual deformation of the membrane edge to deviate from the ideal sphere, it generally manifests as excessive residuals. Therefore, for any current point in the initial point cloud subset, the corresponding residual is determined based on the fitted height and the actual height of each current point. The residual is the average difference between the fitted height and the actual height. If the residual is greater than the preset residual threshold, it indicates that the current point is a distorted point and needs to be deleted.

[0053] After deleting all distorted points, the fitted height of the remaining points is remapped to the original coordinate system to obtain the interference-free elastic surface data of the membrane, which is the target point cloud subset.

[0054] After fitting and correction using the Zernike basis function, the resulting subset of the target point cloud is closer to the ideal sphere. Therefore, when determining the warpage of the central region based on the subset of the target point cloud, the accuracy of the warpage determination can be further improved.

[0055] S412, determine the warping amount of the center region of the effective polymer layer region based on the target point cloud subset.

[0056] Once the target point cloud subset is determined, the warpage of the central region of the effective polymer layer region can be determined based on the target point cloud subset, including: Determine the central region of the effective polymer layer region, and extract the reference point cloud subset of the central region from the target point cloud subset; Obtain the height of the center point of the reference point cloud subset, and determine the average height of the third edge point in the reference point cloud subset; The warping of the central region is determined based on the height of the center point and the average height.

[0057] Specifically, since the central region exhibits the best deformation uniformity and can more accurately reflect the ideal curvature change corresponding to the driving voltage, it is necessary to determine the central region of the effective polymer layer region based on a preset central region range. The central region range is typically defined as concentric small circles within the effective polymer layer region. For example, if the radius of the effective polymer layer region is A, then the radius of the central region... rThe azimuth can be between 0.7A and 0.8A. The determined central region can be used as a reference. Figure 5 .

[0058] Determine the distance between each point in the target point cloud subset and the center of the circle, and extract those less than or equal to... r The points corresponding to the distances are used to define a subset of the reference point cloud.

[0059] Obtain the height of the center point of the reference point cloud subset, which is also the height of the center of the effective polymer layer region, denoted as . ( Figure 3 (where min is the center of the effective polymer layer region); then, determine the third edge point in the reference point cloud subset, and determine the average height of the third edge point, denoted as . The warping amount in the central region is determined using formula (6). : (6) In this way, the amount of warping in the central region is determined.

[0060] S413, the refractive power of the tunable optics is determined based on the central region warpage of the effective polymer layer region and the mapping function between the pre-constructed polymer layer refractive power and the central region warpage.

[0061] Once the warp of the center region of the effective polymer layer is determined, the refractive power of the tunable optics can be determined based on the warp of the center region of the effective polymer layer and the mapping function between the pre-constructed polymer layer refractive power and the warp of the center region.

[0062] In one embodiment, before determining the refractive power of the tunable optics based on the central region warpage of the effective polymer layer region and a mapping function between the polymer layer refractive power and the central region warpage, it is necessary to construct a mapping function between the central region warpage and the polymer layer refractive power, including: Get N The refractive power corresponding to the standard polymer layer; right N Measurements were performed on a set of standard polymer layers to obtain... N The warpage amount in the central region corresponding to the standard polymer layer of the group; right N The refractive power corresponding to the standard polymer layer and N The warpage of the central region corresponding to the standard polymer layer is fitted to obtain the mapping function between the refractive power of the polymer layer and the warpage of the central region.

[0063] In one embodiment, determining the refractive power of the tunable optics based on the amount of warpage in the central region of the effective polymer layer region includes: The refractive power of the tunable optics is determined according to formula (7). D : (7) In formula (7), b For correction amount, The warpage amount in the center region of the effective polymer layer area. b The value range is 2.5 ± 0.1 (per meter).

[0064] Specifically, you can select N A set of standard polymer layers with known refractive power were used to measure the optical properties of the polymer layers using a three-dimensional morphology measurement device. N The warpage in the central region of a standard polymer layer was measured to obtain... N The warpage in the central region of the group. Due to the optical principle of TLens, refractive power and warpage have a linear relationship, which can be analyzed using a linear regression function. N Group of refractive power and N The warpage of the central region is fitted to obtain the mapping function between the refractive power of the polymer layer and the warpage of the central region, as shown in formula (7).

[0065] Once the mapping function is determined, the warpage of the central region of the effective polymer layer can be substituted into the mapping function to obtain the refractive power of the tunable optics.

[0066] As can be seen, this invention can pre-construct a mapping function between the refractive power of the polymer layer and the warpage of the central region. After the polymer layer undergoes elastic deformation, the three-dimensional point cloud data of the film layer is analyzed to obtain the warpage of the central region of the effective polymer layer area. Finally, the refractive power is calculated based on the warpage of the central region and the mapping function. The entire process can be achieved with only an existing three-dimensional laser scanning machine, resulting in low measurement costs. Therefore, the refractive power measurement of all tunable optical devices can be realized throughout the mass production process, ensuring the overall quality of tunable optical devices.

[0067] Based on the same inventive concept as in the foregoing embodiments, this embodiment also provides a device for determining the refractive power of a tunable optical device, the tunable optical device comprising a polymer layer and a MEMS (microelectromechanical system); such as Figure 6 As shown, the device includes: The first processing unit 61 is used to preprocess the three-dimensional point cloud data of the polymer layer to obtain an initial point cloud subset of the effective polymer layer region; the three-dimensional point cloud data of the polymer layer is obtained by scanning the polymer layer when a target driving voltage is applied to the tunable optical device and the target driving voltage remains stable. The second processing unit 62 is used to perform interference removal processing on the initial point cloud subset of the effective polymer layer region using a preset fitting algorithm to obtain the target point cloud subset. The first determining unit 63 is used to determine the warpage amount of the center region of the effective polymer layer region based on the target point cloud subset. The second determining unit 64 is used to determine the refractive power of the tunable optics based on the warpage of the center region of the effective polymer layer region and the mapping function between the pre-constructed polymer layer refractive power and the warpage of the center region.

[0068] Since the apparatus described in the embodiments of the present invention is the apparatus used in implementing the method of determining the refractive power of a tunable optical device according to the embodiments of the present invention, those skilled in the art can understand the specific structure and variations of the apparatus based on the method described in the embodiments of the present invention, and therefore will not be described in detail here. All apparatuses used in the methods of the embodiments of the present invention fall within the scope of protection of the present invention.

[0069] Through one or more embodiments of the present invention, the present invention has the following beneficial effects or advantages: This invention provides a method, apparatus, and tunable optical device for determining the refractive power of a tunable optical device, the tunable optical device comprising a polymer layer; the method includes: preprocessing three-dimensional point cloud data of the polymer layer to obtain an initial point cloud subset of an effective polymer layer region; the three-dimensional point cloud data of the polymer layer is obtained by scanning the polymer layer while a target driving voltage is applied to the tunable optical device and the target driving voltage remains stable; performing interference removal processing on the initial point cloud subset of the effective polymer layer region using a preset fitting algorithm to obtain a target point cloud subset; determining the warpage of the central region of the effective polymer layer region based on the target point cloud subset; and determining the warpage of the central region of the effective polymer layer region based on the warpage of the central region. The diopter of the tunable optics is determined by measuring the diopter. Since changes in the driving voltage cause elastic deformation of the polymer layer, the radius of curvature of the polymer layer also changes, resulting in a change in diopter. Therefore, this invention can pre-construct a mapping function between the diopter of the polymer layer and the warp amount in the central region. After the polymer layer undergoes elastic deformation, the three-dimensional point cloud data of the film layer is analyzed to obtain the warp amount in the central region of the effective polymer layer area. Finally, the diopter is calculated based on the warp amount in the central region and the mapping function. The entire process only requires a three-dimensional topography measurement device, resulting in low measurement costs. Therefore, diopter measurement of all tunable optics can be achieved throughout the mass production process, ensuring the overall quality of the tunable optics.

[0070] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining the refractive power of a tunable optical device, characterized in that, The tunable optical device includes a polymer layer; the method includes: The three-dimensional point cloud data of the polymer layer is preprocessed to obtain an initial point cloud subset of the effective polymer layer region; the three-dimensional point cloud data of the polymer layer is obtained by scanning the polymer layer when a target driving voltage is applied to the tunable optical device and the target driving voltage remains stable. The initial point cloud subset of the effective polymer layer region is processed to remove interference using a preset fitting algorithm to obtain the target point cloud subset; The warpage of the center region of the effective polymer layer region is determined based on the target point cloud subset. The refractive power of the tunable optics is determined based on the central region warpage of the effective polymer layer region and a mapping function between the pre-constructed polymer layer refractive power and the central region warpage.

2. The method as described in claim 1, characterized in that, The preprocessing of the three-dimensional point cloud data of the polymer layer to obtain an initial subset of point clouds for the effective polymer layer region includes: The three-dimensional point cloud data of the polymer layer is filtered to obtain the target three-dimensional point cloud dataset. Extract the planar coordinates of the 3D point cloud data of each target to obtain a planar point set; The first edge point of the planar point set is determined based on the edge detection algorithm; Determine whether the initial region enclosed by the first edge point is the target shape. If so, obtain the height data of the target 3D point cloud data within the initial region, and determine the height variance of the target 3D point cloud data within the initial region based on the height data. If the height variance of the target 3D point cloud data within the initial region is less than a preset threshold, then the second edge point of the initial region is extracted. Traverse the second edge point of the initial region. If the second edge point is determined to be a mutation point, delete the mutation point from the initial region to obtain the initial point cloud subset of the effective polymer layer region.

3. The method as described in claim 2, characterized in that, The step of determining whether the initial region enclosed by the first edge points is the target shape includes: The first edge point is fitted using a circular fitting algorithm to obtain the center and radius of the fitted circle; For each first edge point, determine the distance between the first edge point and the center of the circle, and determine the deviation between the distance and the radius; Determine the root mean square value of all deviations. If the root mean square value is less than a preset deviation threshold, determine the initial region as the target shape.

4. The method as described in claim 2, characterized in that, Determining the second edge point as a mutation point includes: For each second edge point, determine the height difference between the second edge point and a preset number of neighboring points, and determine the average value of the height difference; If the average value is greater than a preset height threshold, then the second edge point is determined to be the mutation point.

5. The method as described in claim 1, characterized in that, The step of using a preset fitting algorithm to perform interference removal processing on the initial point cloud subset of the effective polymer layer region to obtain the target point cloud subset includes: For each point in the initial point cloud subset of the effective polymer layer region, coordinate normalization is performed to obtain the normalized polar coordinates of each point; A linear equation for each point is constructed using Zernikal polynomial basis functions and normalized polar coordinates for each point; the linear equation includes the Zernikal polynomial for each point and the fitting residual. With the goal of minimizing the sum of squared residuals of all points, the coefficients of the Zernike polynomial are obtained by solving the linear equation system using the least squares method. Substituting the coefficients of the Zernike polynomial into the linear equation for each point yields the fitting height for each point; For any current point in the initial point cloud subset, the corresponding residual is determined based on the fitted height and actual height of each current point. If the residual is greater than a preset residual threshold, the current point is determined to be a distortion point. The distorted points in the initial point cloud subset are deleted to obtain the remaining points; the fitted height of the remaining points is remapped to the original coordinate system to obtain the target point cloud subset.

6. The method as described in claim 1, characterized in that, Determining the warpage of the center region of the effective polymer layer region based on the target point cloud subset includes: Determine the central region of the effective polymer layer region, and extract a reference point cloud subset of the central region from the target point cloud subset; Obtain the height of the center point of the reference point cloud subset, and determine the average height of the third edge point in the reference point cloud subset; The warping amount of the central region is determined based on the height of the center point and the average height.

7. The method as described in claim 1, characterized in that, Before determining the refractive power of the tunable optics based on the central region warpage of the effective polymer layer region and a pre-constructed mapping function between the polymer layer refractive power and the central region warpage, the method further includes: Get N The refractive power corresponding to the standard polymer layer; Regarding the N Measurements were performed on a set of standard polymer layers to obtain... N The warpage amount in the central region corresponding to the standard polymer layer of the group; Regarding the N The refractive power corresponding to the standard polymer layer and the N The warpage of the central region corresponding to the standard polymer layer is fitted to obtain the mapping function between the refractive power of the polymer layer and the warpage of the central region.

8. The method as described in claim 7, characterized in that, Determining the refractive power of the tunable optics based on the warpage of the central region of the effective polymer layer region includes: According to the formula Determine the refractive power of the tunable optics. D ;in, The b As a correction amount, the The warpage amount is the amount of warpage in the center region of the effective polymer layer region.

9. An apparatus for determining the diopter of a tunable optical device, characterized in that, The tunable optics includes a polymer layer; the device includes: The first processing unit is used to preprocess the three-dimensional point cloud data of the polymer layer to obtain an initial point cloud subset of the effective polymer layer region; the three-dimensional point cloud data of the polymer layer is obtained by scanning the polymer layer when a target driving voltage is applied to the tunable optical device and the target driving voltage remains stable. The second processing unit is used to perform interference removal processing on the initial point cloud subset of the effective polymer layer region using a preset fitting algorithm to obtain the target point cloud subset. The first determining unit is used to determine the warpage amount of the center region of the effective polymer layer region based on the target point cloud subset. The second determining unit is used to determine the refractive power of the tunable optics based on the warpage of the center region of the effective polymer layer region and a mapping function between the pre-constructed polymer layer refractive power and the warpage of the center region.

10. A tunable optical device, characterized in that, The tunable optical device includes: A glass support layer is used to provide foundation support; A polymer layer is located above the glass support layer; A glass thin film layer is located above the polymer layer; A piezoelectric thin film, located on the glass thin film layer and above the polymer layer, is deposited on the microelectromechanical actuator wafer; Gold bumps are located at the four corners of the microelectromechanical actuator wafer; wherein, An external voltage signal is transmitted to the piezoelectric film through the gold bumps. The piezoelectric film converts the voltage signal into a driving force, which drives the polymer layer to deform and change its curvature.

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