Polarizing sheet inspection method, inspection apparatus, and computer-readable storage medium

Abstract

The application relates to the technical field of optical detection, and provides a polaroid detection method, a detection device and a computer readable storage medium. The polaroid detection method comprises the following steps: acquiring a structure parameter of a polaroid and a preset photographing number n, the structure parameter comprising one or more of a total thickness of the polaroid, a thickness of a release film, a thickness of a protective film, a first offset thickness of an effective detection layer to the release film and a second offset thickness of the effective detection layer to the protective film; determining a focusing position sequence and a layered boundary sequence according to the structure parameter and the photographing number n; controlling a photographing device to take n photographs of the polaroid according to the focusing position sequence and the layered boundary sequence, and outputting a depth interval of the polaroid corresponding to each photographing; when the first layer is photographed, the top region of the effective detection layer can be completely covered, when the last layer is photographed, the bottom region of the polaroid can be completely covered, and the imaging definition of each layer is maximized in the corresponding depth of field range.

Description

Technical Field

[0001] This application belongs to the field of optical inspection technology, and in particular relates to polarizer inspection methods, inspection equipment and computer-readable storage media. Background Technology

[0002] As a key optical component of liquid crystal displays, the quality of the polarizer directly affects the display effect. The thickness of the polarizer is on the order of hundreds of micrometers. In order to detect defects inside the polarizer, it is necessary to photograph the polarizer layer by layer to inspect each layer.

[0003] Existing detection methods involve capturing a set of focus stack images at multiple predetermined depth positions on the polarizer. The depth information at each depth position is estimated using the mechanism of sharpness variation with focus deviation. Based on this depth information, the polarizer is divided into multiple depth intervals, thus obtaining the boundaries of each layer of the polarizer. The above methods have the following problems: (1) The boundaries of each layer and each focus position depend on the depth estimation results. When taking pictures of the first layer, the top information of the effective detection layer of the polarizer may be missed. When taking pictures of the last layer, the image information of the bottom area of ​​the polarizer may not be completely and clearly obtained. The depth of field coverage of each layer is uneven, resulting in inconsistent imaging clarity of each layer. (2) It is necessary to first acquire the focus stack image and then perform depth recovery and layer information conversion. The calculation process is complicated, and the certainty and repeatability of each focus depth and each layer boundary are weak, which is not conducive to automatic focusing and shooting. Summary of the Invention

[0004] In view of this, embodiments of this application provide a polarizer detection method, detection equipment, and computer-readable storage medium to solve the problems of low image clarity, incomplete image information acquisition, and unfavorable conditions for automated execution in the prior art.

[0005] A first aspect of this application provides a polarizer detection method for detecting a polarizer, the polarizer comprising an effective detection layer, a release film above the effective detection layer, and a protective film below the effective detection layer, the polarizer detection method comprising: Obtain the structural parameters of the polarizer and the preset number of photos n. The structural parameters include one or more of the following: the total thickness of the polarizer, the thickness of the release film, the thickness of the protective film, the first offset thickness of the effective detection layer towards the release film, and the second offset thickness of the effective detection layer towards the protective film. Based on the structural parameters and the number of photographs n, the focus position sequence F[0] to F[n-1] and the layer boundary sequence B[0] to B[n] are determined. The layer boundary sequence is used to divide the polarizer into n layers along the thickness direction, with each of the n photographs corresponding to one of the n layers. In the focus position sequence, the first focus position F[0] is located on the upper surface of the polarizer, and the nth focus position F[n-1] is located on the lower surface of the polarizer or inside the protective film. In the layer boundary sequence, the first layer boundary B[0] is located on the upper surface of the polarizer, the (n+1)th layer boundary B[n] is located on the lower surface of the polarizer, and the remaining layer boundaries satisfy that B[i] is located on F[i]. The midpoint between 1] and F[i], i=1 to n 1, and the second layer boundary B[1] is aligned with the position of the effective detection layer after it has shifted the first offset thickness in the direction of the release film; The camera is controlled to take n photos of the polarizer based on the focus position sequence and the layer boundary sequence, and the depth range of the polarizer corresponding to each photo is output.

[0006] In one embodiment, determining the focus position sequence F[0] to F[n-1] based on the structural parameters and the number of shots n includes: If the number of photos taken n>3 and the second offset thickness is greater than 0, the second focus position F[1] is determined based on the thickness of the release film and the first offset thickness; The depth interval is determined based on the total thickness of the polarizer, the thickness of the release film, the thickness of the protective film, the number of photographs n, and the first offset thickness. The third focus position F[2] to the nth focus position are determined based on the second focus position F[1] and the depth interval. One focus position F[n 2]; According to the nth One focus position F[n 2] The total thickness of the polarizer, the thickness of the protective film, and the second offset thickness determine the nth focusing position F[n-1].

[0007] In one embodiment, determining the second focus position F[1] based on the thickness of the release film and the first offset thickness includes: The second layer boundary B is determined based on the thickness of the release film and the first offset thickness [1]; The second focus position F[1] is determined based on the second layer boundary B[1] and the first focus position F[0].

[0008] In one embodiment, according to the nth One focus position F[n 2] The total thickness of the polarizer, the thickness of the protective film, and the second offset thickness determine the nth focusing position F[n-1], including: The nth layer boundary B[n-1] is determined based on the total thickness of the polarizer, the thickness of the protective film, and the second offset thickness; According to the nth One focus position F[n 2] and the nth layer boundary B[n-1] determines the nth focus position F[n-1].

[0009] In one embodiment, the second focus position F[1] to the nth One focus position F[n In [2], the depth interval between each adjacent focus position is equal.

[0010] In one embodiment, determining the focus position sequence F[0] to F[n-1] based on the structural parameters and the number of shots n includes: If the number of photos taken n>3 and the second offset thickness is equal to 0, the second focus position F[1] is determined according to the thickness of the release film and the first offset thickness; Obtain preset adjustable parameters; The nth polarizer is determined based on the adjustable parameters, the total thickness of the polarizer, and the thickness of the protective film. One focus position F[n 2] and the nth focus position F[n-1]; Based on the second focus position F[1] and the nth One focus position F[n 2] Determine the depth interval; The third focus position F[2] to the nth focus position are determined based on the second focus position F[1] and the depth interval. Two focus positions F[n 3).

[0011] In one embodiment, the imaging device is controlled to take n pictures of the polarizer according to the focus position sequence and the layer boundary sequence, and the depth range of the polarizer corresponding to each picture is output, including: Obtain the refractive index of the polarizer; Determine the control quantity sequence based on the focus position sequence and the refractive index; The control sequence is used as the focusing sequence of the imaging device to control the imaging device to take n pictures of the polarizer; The depth range of the polarizer corresponding to each photograph is output based on the layer boundary sequence.

[0012] In one embodiment, determining the focus position sequence F[0] to F[n-1] and the layer boundary sequence B[0] to B[n] based on the structural parameters and the number of shots n includes: If the structural parameters meet the preset verification conditions, the focus position sequence F[0] to F[n-1] and the layer boundary sequence B[0] to B[n] are determined according to the structural parameters and the number of photos n; wherein, the verification conditions include: the range of the sum of the thickness of the release film and the thickness of the protective film, the thickness range of the first offset thickness and the thickness range of the second offset thickness.

[0013] A second aspect of this application provides a polarizer detection device for detecting polarizers, the polarizer including an effective detection layer, a release film above the effective detection layer, and a protective film below the effective detection layer, the polarizer detection device comprising: The acquisition module is used to acquire the structural parameters of the polarizer and the preset number of photos n. The structural parameters include one or more of the following: the total thickness of the polarizer, the thickness of the release film, the thickness of the protective film, the first offset thickness of the effective detection layer to the release film, and the second offset thickness of the effective detection layer to the protective film. The calculation module is used to determine the focus position sequence F[0] to F[n-1] and the layer boundary sequence B[0] to B[n] based on the structural parameters and the number of photos taken n. The layer boundary sequence divides the polarizer into n layers along the thickness direction, with each of the n photos corresponding to one of the n layers. In the focus position sequence, the first focus position F[0] is located on the upper surface of the polarizer, and the nth focus position F[n-1] is located on the lower surface of the polarizer or inside the protective film. In the layer boundary sequence, the first layer boundary B[0] is located on the upper surface of the polarizer, the (n+1)th layer boundary B[n] is located on the lower surface of the polarizer, and the remaining layer boundaries satisfy that B[i] is located on F[i]. The midpoint between 1] and F[i], i=1 to n 1, and the second layer boundary B[1] is aligned with the position of the effective detection layer after it has shifted the first offset thickness in the direction of the release film; The control module is used to control the imaging device to take n pictures of the polarizer according to the focus position sequence and the layer boundary sequence, and output the depth range of the polarizer corresponding to each picture.

[0014] A third aspect of this application provides a detection device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the polarizer detection method as described in the first aspect above.

[0015] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the polarizer detection method as described in the first aspect above.

[0016] The fifth aspect of this application provides a computer program product that, when run on a testing device, causes the testing device to perform the polarizer testing method described in any one of the first aspects.

[0017] The beneficial effects of this application embodiment compared with the prior art are as follows: By obtaining the structural parameters of the polarizer and the preset number of shots, the focus position sequence and layer boundary sequence are determined according to the structural parameters of the polarizer and the number of shots. The second layer boundary is aligned with the position of the effective detection layer after being offset by the first offset thickness towards the release film, so that the position of the first layer of the polarizer is consistent with the position of the effective detection layer after being offset by the first offset thickness. This ensures that when the first layer is photographed, the top area of ​​the effective detection layer can be completely covered, avoiding the omission of information of the effective detection layer. The (n-1)th focus position is set to be located on the lower surface or inside the protective film. The system ensures that the bottom area of ​​the polarizer is completely covered when photographing the last layer. Layer boundaries are set to the midpoint between two adjacent focus points, maximizing the image sharpness of each layer within its corresponding depth of field. The depth of field coverage of adjacent layers is symmetrically connected at the boundaries, avoiding uneven depth of field coverage caused by layer boundary offsets. Furthermore, the entire calculation process does not require pre-acquiring images for depth estimation; it directly outputs all focus positions and layer boundaries at once based on structural parameters and the number of photographs. This approach offers advantages such as high determinism and repeatability, facilitating automated execution of focus control or data acquisition. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0019] Figure 1 This is a schematic diagram of the structure of a polarizer provided in an embodiment of this application; Figure 2 This is a schematic diagram illustrating the implementation process of a polarizer detection method provided in an embodiment of this application; Figure 3This is a schematic diagram of the focus position sequence and layer boundary sequence in the first scenario; Figure 4 This is a schematic diagram of the focus position sequence and layer boundary sequence in the second scenario; Figure 5 This is a schematic diagram of the focus position sequence and layer boundary sequence in the third scenario; Figure 6 This is a flowchart illustrating the determination of the focus position sequence and the layer boundary sequence according to an embodiment of this application; Figure 7 This is a schematic diagram of the structure of the testing equipment provided in the embodiments of this application. Detailed Implementation

[0020] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0021] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0022] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0023] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0024] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrases "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0025] The polarizer detection method provided in this application is illustrated below.

[0026] The polarizer testing method provided in this application is used to test polarizers. For example... Figure 1 As shown, the polarizer includes an effective detection layer, a release film above the effective detection layer, and a protective film below the effective detection layer. The effective detection layer is the functional layer in the polarizer that enables polarization and is also the part that needs to be inspected for defects. The release film and the protective film are located above and below the effective detection layer, respectively, to protect the effective detection layer.

[0027] like Figure 2 As shown, an embodiment of this application provides a polarizer detection method including steps S201 to S203.

[0028] S201: Obtain the structural parameters of the polarizer and the preset number of photos n. The structural parameters include the total thickness of the polarizer, the thickness of the release film, the thickness of the protective film, the first offset thickness of the effective detection layer towards the release film, and the second offset thickness of the effective detection layer towards the protective film.

[0029] The first offset thickness is the distance offset from the junction of the release film and the effective detection layer towards the release film (i.e., upwards), and the second offset thickness is the distance offset from the junction of the protective film and the effective detection layer towards the protective film (i.e., downwards). The first offset thickness, the second offset thickness, and the number of shots can be preset according to the detection requirements of the polarizer.

[0030] S202: Determine the focus position sequence F[0] to F[n-1] and the layer boundary sequence B[0] to B[n] based on the structural parameters and the number of photos taken n, wherein the layer boundary sequence is used to divide the polarizer into n depth intervals along the thickness direction, and the n photos correspond one-to-one with the n depth intervals; in the focus position sequence, the first focus position F[0] is located on the upper surface of the polarizer, and the nth focus position F[n-1] is located on the lower surface of the polarizer or inside the protective film; in the layer boundary sequence, the first layer boundary B[0] is located on the upper surface of the polarizer, the (n+1)th layer boundary B[n] is located on the lower surface of the polarizer, and the remaining layer boundaries satisfy that B[i] is located on F[i]. The midpoint between 1] and F[i], i=1 to n 1, and the second layer boundary B[1] is aligned with the position of the effective detection layer after the first offset thickness is offset in the direction of the release film.

[0031] In one embodiment, the structural parameters are validated before determining the focus position sequence and the layer boundary sequence. If the validation passes, the focus position sequence and the layer boundary sequence are determined based on the structural parameters and the number of shots taken. If the validation fails, an error message is output to remind the user to modify the structural parameters.

[0032] The verification conditions include: the range of the sum of the thickness of the release film and the thickness of the protective film, the range of the first offset thickness, and the range of the second offset thickness. For example, the verification conditions are: the sum of the thickness of the release film and the thickness of the protective film is less than or equal to the total thickness; the first offset thickness is less than the thickness of the release film; the second offset thickness is less than the thickness of the protective film; and the thickness of the effective detection layer calculated based on the total thickness, the thickness of the release film, and the thickness of the protective film is positive.

[0033] Verifying the structural parameters before calculating the focus position sequence and layer boundary sequence can detect illegal or unreasonable input parameters in advance, thus avoiding errors in subsequent calculation results.

[0034] The focus position sequence includes multiple positions located between the upper and lower surfaces of the polarizer, ordered from F[0] to F[n-1] in order of distance from the upper surface of the polarizer. Therefore, the focus position is also the distance from the focus position to the upper surface of the polarizer. The number of focus positions in the focus position sequence is the same as the number of shots, which is n. By controlling the movement of the imaging device so that the focus position of the imaging device is located at the focus position, a clear image of the polarizer can be obtained.

[0035] The layered boundary sequence includes multiple layered boundaries between the upper and lower surfaces of the polarizer, arranged in order of distance from the upper surface of the polarizer, from B[0] to B[n]. The number of layered boundaries in the layered boundary sequence is n+1. The n+1 layered boundaries divide the polarizer into n layers, with adjacent layered boundaries being the upper and lower boundaries of the corresponding layer. The n layers correspond one-to-one with the n focus positions, and the image captured at any focus position is the image of the corresponding layer.

[0036] like Figure 3 As shown, if the number of shots n=3, there are 3 focus positions in the focus position sequence and 4 layer boundaries in the layer boundary sequence. The first focus position F[0] is located on the upper surface of the polarizer, the first layer boundary B[0] is located on the upper surface of the polarizer, and the second layer boundary B[1] is located according to the formula B[1]=R t_top is obtained, where R represents the thickness of the release film, and t_top represents the first offset thickness, that is, the second layer boundary B[1] is aligned with the position of the effective detection layer after being offset by the first offset thickness in the direction of the release film. Therefore, the second layer boundary B[1] is located at the position of the effective detection layer offset upward by the first offset thickness, so that the detection information above the effective detection layer can be obtained. The second focus position F[1] is obtained according to the formula F[1]=(R The second layer boundary B[1] is determined by t_top)×2, thus placing the second layer boundary B[1] at the midpoint between the first focus position F[0] and the second focus position F[1]. The third focus position F[2] is located on the lower surface of the polarizer, and the third layer boundary B[2] is located at the midpoint between the second focus position F[1] and the third focus position F[2]. The fourth layer boundary B[3] is located on the lower surface of the polarizer.

[0037] like Figure 4 As shown, for the case where the number of shots n>3 and the second offset thickness is greater than 0, the first focus position F[0] is located on the upper surface of the polarizer, and the first layer boundary B[0] is located on the upper surface of the polarizer. The second layer boundary B[1] is determined according to the formula B[1]=R The second focus position F[1] is obtained from t_top according to the formula F[1]=(R t_top)×2 is obtained. Therefore, the second layer boundary B[1] is located at the midpoint between the first focus position F[0] and the second focus position F[1]. The lower boundary of the layer that takes pictures based on the first focus position F[0] and the upper boundary of the layer that takes pictures based on the second focus position F[1] are both R. The position of t_top ensures that a clear and effective image of the detection layer can be obtained, and that the depth of field of the two images does not overlap or miss anything.

[0038] Then, based on the total thickness of the polarizer, the thickness of the release film, the thickness of the protective film, the number of shots n, and the first offset thickness, the second focus position F[1] to the nth focus position is determined. One focus position F[n 2] is the depth interval between two adjacent focus positions.

[0039] In one embodiment, the second focus position F[1] to the nth One focus position F[n Between 2], the depth interval between two adjacent focusing positions is equal, that is, the depth interval is a fixed value. The depth interval is determined according to the formula a=[TP-(R-t_top)×2] / (n-3). Where, a represents the depth interval, T represents the total thickness of the polarizer, R represents the thickness of the release film, P represents the thickness of the protective film, and t_top represents the first offset thickness. In the formula, TP represents the thickness between the upper surface of the polarizer and the upper surface of the protective film, (R-t_top)×2 is the second focusing position F[1], and TP-(R-t_top)×2 represents the thickness between F[1] and the upper surface of the protective film. Therefore, the depth interval a is the thickness after dividing the thickness between F[1] and the upper surface of the protective film equally. For the third focusing position F[2] to the nth One focus position F[n 2] According to the formula F[i]=F[1]+(i-1)×a (i=2 to n-2), each focus position is determined, so that the effective detection layer can be photographed at equal intervals according to each focus position, avoiding some areas being too dense or too sparse.

[0040] In other alternative embodiments, non-uniform depth intervals can be set according to the material of the polarizer or the detection requirements, and the third focusing position F[2] to the nth focusing position can be determined according to the non-uniform depth intervals. One focus position F[n 2).

[0041] Then, the nth layer boundary B[n-1] is determined according to the formula B[n-1]=T-P+t_bottom, where t_bottom represents the second offset thickness. Therefore, the nth layer boundary B[n-1] is aligned with the position of the effective detection layer after being offset by the second offset thickness towards the protective film. Therefore, the nth... The lower boundary of the layer in a single image is located below the effective detection layer, thus obtaining an image of the complete lower boundary of the effective detection layer.

[0042] The nth focus position F[n-1] is determined according to the formula F[n]. 1]=F[n 2]+t_bottom×2 is determined, thus making the nth layer boundary B[n-1] located at the nth layer boundary. One focus position F[n 2] and the midpoint of the nth focus position F[n-1], such that the nth focus position... The lower boundary of the first photo is aligned with the upper boundary of the last photo to prevent data loss.

[0043] The (n+1)th layer boundary B[n] is located on the lower surface of the polarizer. After obtaining the focus positions, for the third layer boundary to the nth layer boundary... Two hierarchical boundaries, based on B[i] being located in F[i] The midpoint between F[i] and F[i] can be calculated.

[0044] In the above embodiments, the second layer boundary is aligned with the position of the effective detection layer after being offset by the first offset thickness in the direction of the release film according to the structural parameters of the polarizer, ensuring that the first layer boundary is above the effective detection layer and avoiding the omission of information at the top of the effective detection layer; the (n-1)th focus position is set inside the protective film so that the depth of field of the last photo completely covers the bottom area of ​​the polarizer, avoiding the loss or blurring of image information at the bottom of the polarizer; the layer boundary is set as the midpoint of two adjacent focus positions so that each layer is symmetrically connected at the boundary, ensuring consistent image clarity of each layer.

[0045] like Figure 5 As shown, for the case where the number of shots n>3 and the second offset thickness is equal to 0, the first focus position F[0] is located on the upper surface of the polarizer, and the first layer boundary B[0] is located on the upper surface of the polarizer. The second layer boundary B[1] is determined according to the formula B[1]=R The second focus position F[1] is obtained from t_top according to the formula F[1]=(R t_top)×2 is obtained. Therefore, the second layer boundary B[1] is located at the midpoint between the first focus position F[0] and the second focus position F[1]. The lower boundary of the layer that takes pictures based on the first focus position F[0] and the upper boundary of the layer that takes pictures based on the second focus position F[1] are both R. The position of t_top ensures that a clear and effective image of the detection layer can be obtained, and that the depth of field of the two images does not overlap or miss anything.

[0046] Since the second offset thickness is equal to 0, an adjustable parameter q is introduced, and the adjustable parameter q is the nth... One focus position F[n 2] The distance between the nth layer boundary B[n-1] and the nth layer boundary B[n-1] is B[n-1] = F[n-2] + q. The nth layer boundary B[n-1] is determined by the formula B[n-2] + q. 1]=T P is determined, indicating that the nth layer boundary B[n-1] is located at the junction of the effective detection layer and the protective film. The nth layer boundary can be determined based on the nth layer boundary B[n-1]. One focus position F[n 2]= T Pq. Since the nth layer boundary B[n-1] is the nth... One focus position F[n 2] and the midpoint of the nth focus position F[n-1], therefore, the nth focus position F[n-1] = T P+ q.

[0047] Based on the number of shots, the second focus position F[1] is compared with the nth focus position. One focus position F[n The thickness between 2] is divided equally to obtain the depth interval. The depth interval b is determined according to the formula b=[T-(Pq)-(R-t_top)×2-q×2] / (n-3).

[0048] The third focus position F[2] to the nth focus position can be determined based on the second focus position F[1] and the depth interval. Two focus positions F[n 3).

[0049] The (n+1)th layer boundary B[n] is located on the lower surface of the polarizer. After obtaining the focus positions, for the third layer boundary to the nth layer boundary... Two hierarchical boundaries, based on B[i] being located in F[i] The midpoint between F[i] and F[i] can be calculated.

[0050] In the above embodiments, the nth One layer boundary is set at the junction of the effective detection layer and the protective film. The nth layer boundary is determined based on the adjustable parameters, the total thickness of the polarizer, and the thickness of the protective film. Two focus positions and the (n-1)th focus position, then move the second focus position to the nth focus position. The thickness between the two focus positions is divided equally to obtain other focus positions, ensuring the uniformity and consistency of the depth of field coverage of each layer in the middle.

[0051] It is understood that in other embodiments, non-uniform depth intervals can also be set according to the material of the polarizer or the detection requirements. The adjustable parameter q can also represent the distance between the nth layer boundary B[n-1] and the lower surface of the polarizer. One focus position F[n 2] The distance between the nth focus position F[n-1].

[0052] In one embodiment, the polarizer detection method provided in this application is as follows: Figure 6As shown, first obtain the structural parameters of the polarizer and the preset number of photos, and determine whether the number of photos is greater than 3. If the number of photos is not greater than 3, determine 3 focus position sequences and 4 layer boundary sequences based on the total thickness of the polarizer, the thickness of the release film and the first offset thickness. If the number of photos is greater than 3, first determine whether the second offset thickness is greater than 0. If the second offset thickness is greater than 0, first determine the first focus position F[0], the second focus position F[1], the first layer boundary B[0], the second layer boundary B[1] and the n+1th layer boundary B[n], and then determine the depth interval based on the total thickness of the polarizer, the thickness of the release film, the thickness of the protective film, the first offset thickness and the number of photos, and determine the third focus position F[2] to the nth layer boundary based on the depth interval. One focus position F[n 2]. Then, according to the nth... One focus position F[n 2] Determine the nth focus position F[n-1]. If the second offset thickness is equal to 0, first determine the first focus position F[0], the second focus position F[1], the first layer boundary B[0], the second layer boundary B[1], and the (n+1)th layer boundary B[n]. Then, determine the depth interval based on the total thickness of the polarizer, the thickness of the release film, the thickness of the protective film, the first offset thickness, the adjustable parameters, and the number of shots. Determine the third focus position F[2] to the nth focus position based on the depth interval. One focus position F[n 2]. Then, according to the nth... One focus position F[n [2] Determine the nth focus position F[n-1]. After determining the focus position sequence, determine the third layer boundary B[2] to the (n-1)th layer boundary B[n-1] based on the focus position sequence.

[0053] S203: Control the imaging device to take n pictures of the polarizer according to the focus position sequence and the layer boundary sequence, and output the depth range of the polarizer corresponding to each picture.

[0054] Specifically, the focus position sequence is a depth sequence calculated using air as the medium. However, the propagation distance of light in the polarizer is not equal to its propagation distance in air. Therefore, after obtaining the focus position sequence, the refractive index of the polarizer is acquired, and the control quantity sequence is determined based on the focus position sequence and the refractive index, thereby eliminating the influence of the medium refraction effect on the focusing accuracy and improving the focusing accuracy. The refractive index is the equivalent refractive index of each layer of the polarizer at the detection wavelength, which can be obtained by weighted averaging or calibration of the refractive indices of each layer. The control quantities in the control quantity sequence are calculated according to the formula Z[i] = F[i] / n_ref, where Z[i] is the control quantity and n_ref represents the refractive index.

[0055] After obtaining the control quantity sequence, the control quantity sequence is used as the focusing sequence of the imaging device to control the imaging device to take n pictures of the polarizer. Based on the layer boundary sequence, the depth range of the polarizer corresponding to each picture is output, providing data basis for subsequent image processing and defect detection.

[0056] The following section describes the calculation process of the focus position sequence and the layer boundary sequence using a specific calculation scenario.

[0057] For example, the total thickness T of the polarizer is 417 μm, the thickness R of the release film is 75 μm, the thickness P of the protective film is 25 μm, the first offset thickness t_top is 10 μm, the second offset thickness t_bottom is 10 μm, and the number of photos n is 6.

[0058] First, parameter verification was performed: R+P=75μm +25μm =100μm<417μm, t_top=10μm≤R, t_bottom=10μm≤P, and the verification passed.

[0059] The first focusing position F[0] is located on the upper surface of the polarizer, F[0] = 0 μm. The first layer boundary B[0] is located on the upper surface of the polarizer, B[0] = 0 μm. The second layer boundary B[1] satisfies B[1] = R - t_top = 65 μm. Since the second layer boundary B[1] is located at the midpoint between the first focusing position F[0] and the second focusing position F[1], the second focusing position F[1] = 130 μm is determined.

[0060] The depth interval a = [TP - (R - t_top) × 2] / (n - 3) ≈ 87.33 μm. Based on the depth interval, the third focus position F[2] = 217.33 μm, the fourth focus position F[3] = 304.67 μm, and the fifth focus position F[4] = 392 μm are determined.

[0061] The sixth layer boundary B[5] satisfies B[5]=T-P+t_bottom=402μm. Since the sixth layer boundary is located at the midpoint between the fifth focus position F[4] and the sixth focus position F[5], the sixth focus position F[5] is determined to be 412μm.

[0062] Therefore, the focus position sequence is F[0]=0μm, F[1]=130μm, F[2]=217.33μm, F[3]=304.67μm, F[4]=392μm, F[5]=412μm.

[0063] Based on the fact that the layer boundary is located at the midpoint of two adjacent focus positions, the second to fifth layer boundaries are obtained. The layer boundary sequence is B[0]=0μm, B[1]=65μm, B[2]=173.67μm, B[3]=261μm, B[4]=348.33μm, B[5]=402μm, B[6]=417μm.

[0064] For example, the total thickness T of the polarizer is 417 μm, the thickness R of the release film is 75 μm, the thickness P of the protective film is 25 μm, the first offset thickness t_top is 10 μm, the second offset thickness t_bottom is 0, the number of photos n is 6, and the adjustable parameter q=10 μm.

[0065] First, parameter verification was performed: R+P=75μm +25μm =100μm<417μm, t_top=10μm≤R, t_bottom=10μm≤P, q=10μm≤P. The verification passed.

[0066] The first focusing position F[0] is located on the upper surface of the polarizer, F[0] = 0 μm. The first layer boundary B[0] is located on the upper surface of the polarizer, B[0] = 0 μm. The second layer boundary B[1] satisfies B[1] = R - t_top = 65 μm. Since the second layer boundary B[1] is located at the midpoint between the first focusing position F[0] and the second focusing position F[1], the second focusing position F[1] = 130 μm is determined.

[0067] Depth interval b = [T - (Pq) - (R - t_top) × 2 - q × 2] / (n - 3) = 84 μm; Based on the depth interval, the third focus position F[2] = 214μm, the fourth focus position F[3] = 298μm, the fifth focus position F[4] = 382μm, and the sixth focus position F[5] = 402μm are obtained.

[0068] Therefore, the focus position sequence is F[0]=0μm, F[1]=130μm, F[2]=214μm, F[3]=298μm, F[4]=382μm, F[5]=402μm.

[0069] The layer boundary sequence calculated based on the focus position sequence is B[0]=0μm, B[1]=65μm, B[2]=172μm, B[3]=256μm, B[4]=340μm, B[5]=392μm, B[6]=417μm.

[0070] In this application, the focus position sequence and layer boundary sequence are calculated based on the structural parameters of the polarizer and the preset number of shots. The second layer boundary is aligned with the position of the effective detection layer after being offset by the first offset thickness towards the release film, ensuring that the first layer shot can completely cover the top area of ​​the effective detection layer and avoid reflection interference from the top physical bonding interface. The (n-1)th focus position is set on the lower surface of the polarizer or inside the protective film, ensuring that the depth of field of the last shot covers the bottom area of ​​the polarizer and avoiding the loss of bottom image information. The layer boundaries are all set to the midpoint of two adjacent focus positions, so that each layer is symmetrically connected at the boundary, ensuring the consistency of image sharpness of each layer. At the same time, the focus position sequence and layer boundary sequence can be output based on the structural parameters and the number of shots, which has the advantages of strong determinism and high repeatability, and is easy to automate.

[0071] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0072] Figure 7 This is a schematic diagram of the structure of the testing equipment provided in the embodiments of this application.

[0073] like Figure 7 As shown, the detection device in this embodiment includes: a processor 71, a memory 72, and a computer program 73 stored in the memory 72 and executable on the processor 71. When the processor 71 executes the computer program 73, it implements the steps in the above-described polarizer detection method embodiment, for example... Figure 2 Steps S201 to S203 are shown.

[0074] For example, the computer program 73 may be divided into one or more modules / units, which are stored in the memory 72 and executed by the processor 71 to complete this application. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 73 in the detection device.

[0075] Those skilled in the art will understand that Figure 7 This is merely an example of a testing device and does not constitute a limitation on the testing device. It may include more or fewer components than shown, or combine certain components, or different components. For example, the testing device may also include input / output devices, network access devices, buses, etc.

[0076] The processor 71 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0077] The memory 72 can be an internal storage unit of the testing device, such as a hard drive or memory. The memory 72 can also be an external storage device of the testing device, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, the memory 72 can include both internal and external storage units. The memory 72 is used to store the computer program and other programs and data required by the testing device. The memory 72 can also be used to temporarily store data that has been output or will be output.

[0078] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0079] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0080] In the embodiments provided in this application, it should be understood that the disclosed apparatus / detection devices and methods can be implemented in other ways. For example, the apparatus / detection device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0081] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0082] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0083] If an integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0084] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0085] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for detecting polarizers, used to detect polarizers, the polarizer comprising an effective detection layer, a release film above the effective detection layer, and a protective film below the effective detection layer, characterized in that, The polarizer detection method includes: Obtain the structural parameters of the polarizer and the preset number of photos n. The structural parameters include one or more of the following: the total thickness of the polarizer, the thickness of the release film, the thickness of the protective film, the first offset thickness of the effective detection layer towards the release film, and the second offset thickness of the effective detection layer towards the protective film. Based on the structural parameters and the number of photographs n, the focus position sequence F[0] to F[n-1] and the layer boundary sequence B[0] to B[n] are determined. The layer boundary sequence is used to divide the polarizer into n layers along the thickness direction, with each of the n photographs corresponding to one of the n layers. In the focus position sequence, the first focus position F[0] is located on the upper surface of the polarizer, and the nth focus position F[n-1] is located on the lower surface of the polarizer or inside the protective film. In the layer boundary sequence, the first layer boundary B[0] is located on the upper surface of the polarizer, the (n+1)th layer boundary B[n] is located on the lower surface of the polarizer, and the remaining layer boundaries satisfy that B[i] is located on F[i]. The midpoint between 1] and F[i], i=1 to n 1, and the second layer boundary B[1] is aligned with the position of the effective detection layer after it has shifted the first offset thickness in the direction of the release film; The camera is controlled to take n photos of the polarizer based on the focus position sequence and the layer boundary sequence, and the depth range of the polarizer corresponding to each photo is output.

2. The polarizer detection method according to claim 1, characterized in that, The focus position sequence F[0] to F[n-1] is determined based on the structural parameters and the number of shots n, including: If the number of photos taken n>3 and the second offset thickness is greater than 0, the second focus position F[1] is determined based on the thickness of the release film and the first offset thickness; The depth interval is determined based on the total thickness of the polarizer, the thickness of the release film, the thickness of the protective film, the number of photographs n, and the first offset thickness. The third focus position F[2] to the nth focus position are determined based on the second focus position F[1] and the depth interval. One focus position F[n 2]; According to the nth One focus position F[n 2] The total thickness of the polarizer, the thickness of the protective film, and the second offset thickness determine the nth focusing position F[n-1].

3. The polarizer detection method according to claim 2, characterized in that, Determining the second focus position F[1] based on the thickness of the release film and the first offset thickness includes: The second layer boundary B is determined based on the thickness of the release film and the first offset thickness [1]; The second focus position F[1] is determined based on the second layer boundary B[1] and the first focus position F[0].

4. The polarizer detection method according to claim 2, characterized in that, According to the nth One focus position F[n 2] The total thickness of the polarizer, the thickness of the protective film, and the second offset thickness determine the nth focusing position F[n-1], including: The nth layer boundary B[n-1] is determined based on the total thickness of the polarizer, the thickness of the protective film, and the second offset thickness; According to the nth One focus position F[n 2] and the nth layer boundary B[n-1] determines the nth focus position F[n-1].

5. The polarizer detection method according to claim 2, characterized in that, The second focusing position F[1] to the nth One focus position F[n In [2], the depth interval between each adjacent focus position is equal.

6. The polarizer detection method according to claim 1, characterized in that, The focus position sequence F[0] to F[n-1] is determined based on the structural parameters and the number of shots n, including: If the number of photos taken n>3 and the second offset thickness is equal to 0, the second focus position F[1] is determined according to the thickness of the release film and the first offset thickness; Obtain preset adjustable parameters; The nth polarizer is determined based on the adjustable parameters, the total thickness of the polarizer, and the thickness of the protective film. One focus position F[n 2] and the nth focus position F[n-1]; Based on the second focus position F[1] and the nth One focus position F[n 2] Determine the depth interval; The third focus position F[2] to the nth focus position are determined based on the second focus position F[1] and the depth interval. Two focus positions F[n 3).

7. The polarizer detection method according to claim 1, characterized in that, The imaging device is controlled to take n pictures of the polarizer according to the focus position sequence and the layer boundary sequence, and the depth range of the polarizer corresponding to each picture is output, including: Obtain the refractive index of the polarizer; Determine the control quantity sequence based on the focus position sequence and the refractive index; The control sequence is used as the focusing sequence of the imaging device to control the imaging device to take n pictures of the polarizer; The depth range of the polarizer corresponding to each photograph is output based on the layer boundary sequence.

8. The polarizer detection method according to claim 1, characterized in that, Based on the structural parameters and the number of shots n, the focus position sequence F[0] to F[n-1] and the layer boundary sequence B[0] to B[n] are determined, including: If the structural parameters meet the preset verification conditions, the focus position sequence F[0] to F[n-1] and the layer boundary sequence B[0] to B[n] are determined according to the structural parameters and the number of photos n; wherein, the verification conditions include: the range of the sum of the thickness of the release film and the thickness of the protective film, the thickness range of the first offset thickness and the thickness range of the second offset thickness.

9. A detection device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the polarizer detection method as described in any one of claims 1 to 8.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the polarizer detection method as described in any one of claims 1 to 8.

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