A curved screen defect detection device and method

Abstract

The present application relates to the technical field of curved screen defect detection, in particular to a curved screen defect detection device and method, which can solve the problem of loss of spatial information of edge points of curved screens caused by the existing display screen defect detection system for defect detection of curved screens to a certain extent. The device comprises an imaging module, a beam splitter, a front illumination mirror, an illumination collimating mirror, a light source module, a placement platform and a defect detection module. The imaging module is arranged on one side of the beam splitter. The front illumination mirror is arranged on the other side of the beam splitter, and is used for compensating the exit angle of reflected light of the curved screen to be detected. The light source module is arranged on the side of the illumination collimating mirror away from the beam splitter. The placement platform is arranged on the side of the front illumination mirror away from the beam splitter, and is used for placing the curved screen to be detected. The defect detection module is connected with the imaging module, and is used for defect detection on the image of the curved screen to be detected collected by the imaging module and output of the detection result.

Description

Technical Field

[0001] This invention relates to the field of curved screen defect detection technology, and more specifically, to a curved screen defect detection device and method. Background Technology

[0002] As digital technology products are used in more and more scenarios, the types and specifications of displays used in these products are becoming increasingly diverse. To improve display production efficiency, defect detection is necessary. Different defect detection schemes need to be developed for different types and specifications of displays to improve the sensitivity and accuracy of defect detection.

[0003] Currently, such as Figure 1 As shown, the existing display screen defect detection system includes an imaging module, a beam splitter, a light source module, and a platform. The beam splitter is located below the imaging module, and the platform is located below the beam splitter for placing the display screen to be inspected. The light source module is located on one side of the beam splitter. Figure 1 The display screen defect detection system shown uses coaxial illumination in bright field illumination. This illumination method ensures that the center of the imaging module, the center of the beam splitter, and the center of the display screen under test are on the same vertical axis, and the center of the light source module and the center of the beam splitter are on the same horizontal axis. Figure 1 The specific detection process of the display screen defect detection system shown is as follows: First, the light beam emitted by the light source module is reflected onto the display screen to be inspected by a beam splitter; then, the light beam reflected by the display screen carries the spatial information of each point on the display screen; further, the light beam carrying the spatial information of each point on the display screen is focused onto the line scan camera in the imaging module by the imaging objective lens in the imaging module; finally, the line scan camera acquires the image information of the display screen to be inspected and transmits it to the server for defect detection.

[0004] However, when using the above-mentioned display defect detection system to detect defects in the curved screen under test, because the radius of curvature of the curved screen under test is very small, when the illumination beam generated by the above-mentioned coaxial illumination method is reflected on the curved screen under test, the reflected light from the edge point of the curved screen has a large exit angle and cannot return along the original optical path. As a result, the spatial information of the edge point of the curved screen cannot be received by the imaging module, thus causing the spatial information of the edge point of the curved screen to be lost. Summary of the Invention

[0005] To address the problem that existing display defect detection systems cause the loss of spatial information at the edges of curved screens, this invention provides a curved screen defect detection device and method.

[0006] The embodiments of the present invention are implemented as follows:

[0007] In a first aspect, embodiments of the present invention provide a curved screen defect detection device, comprising: an imaging module, a beam splitter, a front illumination mirror, an illumination collimating mirror, a light source module, a placement platform, and a defect detection module;

[0008] The imaging module is located on one side of the beam splitter, and the center of the imaging module and the center of the beam splitter are located on the same central axis in the horizontal direction.

[0009] The front illumination mirror is located on the other side of the beam splitter, and the center of the front illumination mirror and the center of the beam splitter are located on the same central axis in the horizontal direction. The front illumination mirror is used to compensate for the exit angle of the light reflected from the curved screen to be tested.

[0010] The center of the illumination collimating lens and the center of the beam splitter are on the same vertical central axis;

[0011] The light source module is located on the side of the illumination collimating lens away from the beam splitter, and the center of the light source module and the center of the illumination collimating lens are on the same vertical central axis.

[0012] The placement platform is located on the side of the front illumination mirror away from the beam splitter. The placement platform is used to place the curved screen to be tested, which is designed as a curved cylindrical structure.

[0013] The defect detection module is connected to the imaging module. The defect detection module is used to detect defects in the curved screen image to be detected acquired by the imaging module and output the detection results.

[0014] In one possible implementation of the first aspect, the front illumination mirror includes a first positive lens and a second positive lens;

[0015] The center of the first positive lens and the center of the second positive lens are set on the same central axis in the horizontal direction;

[0016] The first positive lens is positioned on the side closest to the storage platform;

[0017] The second positive lens is positioned on the side closest to the beam splitter.

[0018] In one possible implementation of the first aspect, the focal length of the front illumination mirror is calculated based on the radius of curvature of the curved screen to be tested and the working distance, wherein the working distance is the distance between the front illumination mirror and the curved screen to be tested.

[0019] In one possible implementation of the first aspect, the focal length of the front illumination mirror is calculated using the following formula:

[0020] f′=L+R,

[0021] Where f′ represents the focal length of the front illumination mirror, L represents the working distance, and R represents the radius of curvature of the curved screen to be tested.

[0022] In one possible implementation of the first aspect, the imaging module includes an imaging objective and a line scan camera;

[0023] The imaging objective lens is connected to the line scan camera;

[0024] The imaging objective lens is positioned on the side closest to the beam splitter.

[0025] In one possible implementation of the first aspect, the depth of field of the imaging objective is calculated using the following formula:

[0026]

[0027] Where ΔL represents the depth of field of the imaging objective, F represents the image square number of the imaging objective, δ represents the minimum image square resolution of the line scan camera, f′ represents the focal length of the front illumination lens, and L represents the working distance.

[0028] In one possible implementation of the first aspect, the depth of field of the imaging objective and the minimum image resolution of the curved screen defect detection device are negatively correlated.

[0029] In one possible implementation of the first aspect, the minimum image resolution of the curved screen defect detection device is calculated using the following formula:

[0030] δ min =1.22λF,

[0031] Where, δ min λ represents the minimum image resolution of the curved screen defect detection device, λ represents the wavelength of the illumination source in the light source module, and F represents the image number of the imaging objective lens.

[0032] In one possible implementation of the first aspect, the curved screen defect detection device further includes a control module, which is communicatively connected to the light source module, the imaging module and the defect detection module respectively.

[0033] The control module is used for:

[0034] When the light source module is turned on, the control imaging module acquires an image of the curved screen to be detected. The image of the curved screen to be detected includes the spatial information of all points on the curved screen to be detected.

[0035] The defect detection module controls the defect detection of the curved screen image to be inspected;

[0036] Based on the defect detection results, determine whether the curved screen to be tested needs to be rejected.

[0037] The embodiments of the present invention are implemented as follows:

[0038] Secondly, embodiments of the present invention provide a method for detecting defects in curved screens, including:

[0039] Turn on the control light source module;

[0040] While the light source module is turned on, the imaging module is controlled to acquire the image of the curved screen to be tested. The image of the curved screen to be tested includes the spatial information of all points on the curved screen to be tested. The curved screen to be tested is designed as a curved cylindrical structure.

[0041] Receive images of curved screens to be inspected and perform defect detection on them;

[0042] Based on the defect detection results, determine whether the curved screen to be tested needs to be rejected.

[0043] The beneficial effects of this invention are as follows: By setting a front illumination mirror between the placement platform and the beam splitter, and further by using the front illumination mirror to converge and modulate the reflected light after it has passed through the curved screen to be tested, the exit angle of the reflected light can be reduced, thereby avoiding the loss of spatial information of the upper edge points of the curved screen to be tested; furthermore, by using a front illumination mirror in both the illumination optical path and the imaging optical path, the integration of the curved screen defect detection device can be improved. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the existing display screen defect detection system.

[0046] Figure 2 This is a schematic diagram of a curved screen defect detection device according to one or more embodiments of the present invention;

[0047] Figure 3a This is a schematic diagram of the illumination optical path of the front illumination mirror in a curved screen defect detection device according to one or more embodiments of the present invention;

[0048] Figure 3b This is a schematic diagram of the reflected light path after the front illumination mirror is reflected by the curved screen to be tested in a curved screen defect detection device according to one or more embodiments of the present invention;

[0049] Figure 4aThis is a schematic diagram illustrating the principle of the diffuse modulation of incident light by the curved screen under test when using an existing display defect detection system to inspect a curved screen.

[0050] Figure 4b This is a schematic diagram illustrating the principle of the front illumination mirror converging and modulating incident light in a curved screen defect detection device according to one or more embodiments of the present invention.

[0051] Figure 5 A schematic diagram illustrating the principle of compensation for the emission angle of reflected light from the front illumination mirror in a curved screen defect detection device according to one or more embodiments of the present invention.

[0052] Figure 6 This is a schematic diagram of the surface model structure of the curved screen to be inspected in a curved screen defect detection device according to one or more embodiments of the present invention;

[0053] Figure 7 This is a flowchart of a method for detecting defects in a curved screen according to one or more embodiments of the present invention;

[0054] Illustration:

[0055] Among them, 1-imaging module, 10-imaging objective lens, 11-line scan camera; 2-beam splitter; 3-front illumination lens, 30-first positive lens, 31-second positive lens; 4-illumination collimating lens; 5-light source module; 6-placement platform; 7-defect detection module; 8-curved screen to be tested; 9-control module. Detailed Implementation

[0056] To make the objectives, implementation methods and advantages of the present invention clearer, the exemplary embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of the present invention. Obviously, the described exemplary embodiments are only some embodiments of the present invention, and not all embodiments.

[0057] It should be noted that the brief descriptions of terminology in this invention are merely for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this invention. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0058] In this invention, the terms "first," "second," "third," etc., used in the specification, claims, and accompanying drawings are used to distinguish similar or related objects or entities, and do not necessarily imply a specific order or sequence, unless otherwise specified. It should be understood that such terms can be used interchangeably where appropriate.

[0059] The terms “including” and “having”, “for” and any variations thereof are intended to cover but not exclusively include, for example, a product or device that includes a range of components is not necessarily limited to all of the components that are clearly listed, but may include other components that are not clearly listed or that are inherent to such product or device.

[0060] The terms "setup," "connection," and "installation" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0061] The terms "module" and "system" refer to components that, based on a combination of corresponding hardware structures and software programs, can implement the corresponding steps of this invention.

[0062] The lighting modes of the light source module 5 can be divided into bright field lighting mode and dark field lighting mode; the bright field lighting mode includes coaxial lighting mode, etc.

[0063] Adopting such Figure 1 When the display screen defect detection system shown performs defect detection on the curved screen 8 to be tested, the curvature radius of the curved screen 8 to be tested is very small, resulting in a large difference in the imaging distance between different points on the curved screen 8 to be tested. In particular, for the existing display screen defect detection system, i.e. the small depth of field defect detection system, it will cause the imaging of the edge points of the curved screen to be unclear.

[0064] Figure 2 A schematic diagram of a curved screen defect detection device according to an embodiment of the present invention is shown.

[0065] In some embodiments, such as Figure 2 As shown, a curved screen defect detection device of the present invention includes: an imaging module 1, a beam splitter 2, a front illumination mirror 3, an illumination collimating mirror 4, a light source module 5, a placement platform 6, and a defect detection module 7.

[0066] The imaging module 1 is located on one side of the beam splitter 2, and the center of the imaging module 1 and the center of the beam splitter 2 are located on the same central axis in the horizontal direction.

[0067] The front illumination mirror 3 is located on the other side of the beam splitter 2, and the center of the front illumination mirror 3 and the center of the beam splitter 2 are located on the same central axis in the horizontal direction. The front illumination mirror 3 is used to compensate for the exit angle of the reflected light from the curved screen 8 to be tested.

[0068] The center of the illumination collimating lens 4 and the center of the beam splitter 2 are on the same vertical central axis;

[0069] The light source module 5 is located on the side of the illumination collimating lens 4 away from the beam splitter 2, and the center of the light source module 5 and the center of the illumination collimating lens 4 are on the same central axis in the vertical direction.

[0070] The placement platform 6 is located on the side of the front illumination mirror 3 away from the beam splitter 2. The placement platform 6 is used to place the curved screen 8 to be tested, which is designed as a curved cylindrical structure.

[0071] The defect detection module 7 is communicatively connected to the imaging module 1. The defect detection module 7 is used to perform defect detection on the image of the curved screen to be detected acquired by the imaging module 1 and output the detection results.

[0072] It should be noted that in the above scheme, by adding a front illumination mirror 3 to compensate for the emission angle of the reflected light from the curved screen 8 to be tested, the process of matching the illumination pupil can be completed. This can achieve a certain degree of convergence of the illumination beam emitted by the light source module 5 onto the curved screen 8 to be tested, thereby adjusting the emission angle of the reflected light from each point (including edge points) on the curved screen 8 to be tested. This allows the beam carrying the spatial information of each point (including edge points) on the curved screen 8 to be tested to return along the original incident light path, avoiding the loss of spatial information of the edge points.

[0073] It should also be noted that, Figure 2 The front illumination mirror 3 not only participates in the illumination process, but also serves as the front structure of the imaging system, namely the imaging module 1, in the subsequent imaging process. The light reflected by the curved screen 8 to be tested passes through the front illumination mirror 3 and the imaging module 1 in sequence to form an image. Figure 2 The two dashed lines in the diagram refer to the horizontal and vertical central axes, respectively.

[0074] Figure 6 The diagram illustrates a schematic structural representation of the surface model of the curved screen to be inspected in a curved screen defect detection device according to an embodiment of the present invention.

[0075] like Figure 6 As shown, the surface of the curved screen 8 to be inspected is designed as a curved cylindrical structure. Specifically, by introducing field curvature aberration in the optical path design, the planar surface of the curved screen 8 to be inspected is changed into a curved cylindrical surface, thereby increasing the depth of field of the curved screen defect detection device to a certain extent.

[0076] In the above scheme, the object surface of the curved screen 8 to be inspected is designed as a curved cylindrical structure, which can highly reproduce the three-dimensional surface structure features of a real 2.5D curved screen. Its object surface directly reproduces the contour of the curved screen 8 to be inspected. Therefore, when considering the depth of field, it is not necessary to consider the difference in working distance between points on the curved screen 8 to be inspected due to the object surface not being planar; only the change in working distance caused by the positional deviation of each curved screen 8 on the inspection pipeline needs to be considered. Designing the curved screen 8 to be inspected as a curved cylindrical surface solves the problem of excessively small depth of field of the imaging objective to a certain extent. It can also appropriately increase the aperture of the curved screen defect detection device, increase the light throughput of the curved screen 8 to be inspected, and increase the minimum image resolution of the curved screen defect detection device.

[0077] Figure 3a The illustration shows a schematic diagram of the illumination optical path of the front illumination mirror 3 in a curved screen defect detection device according to an embodiment of the present invention.

[0078] Figure 3b The illustration shows a schematic diagram of the reflected light path after the front illumination mirror 3 is reflected by the curved screen 8 to be tested in a curved screen defect detection device according to an embodiment of the present invention.

[0079] In some embodiments, such as Figure 3a and Figure 3b As shown, the front illumination mirror 3 is a positive lens group, which includes a first positive lens 30 and a second positive lens 31;

[0080] The center of the first positive lens 30 and the center of the second positive lens 31 are set on the same central axis in the horizontal direction;

[0081] The first positive lens 30 is positioned on the side closest to the storage platform 6;

[0082] The second positive lens 31 is positioned on the side closest to the beam splitter 2.

[0083] It should be noted that, from Figure 3a and Figure 3b As can be seen, the illumination beam emitted by the light source module 5 is reflected by the beam splitter 2 to the front illumination mirror 3. It first passes through the first positive lens 30 of the front illumination mirror 3, then through the second positive lens 31, before converging onto the curved screen 8 to be tested. The reflected beams from each point (including edge points) on the curved screen 8 can all return to the front illumination mirror 3, effectively solving the problem of lost spatial information at the edge points of the curved screen 8. Furthermore, both the first positive lens 30 and the second positive lens 31 can be biconvex lenses, plano-convex lenses, or concave-convex lenses. The front illumination mirror 3 in the accompanying drawings is a schematic diagram and does not represent the type of its positive lens group. The specific type of positive lens used can be selected according to the actual scenario, and this invention does not impose any restrictions on it.

[0084] Figure 4a An exemplary diagram illustrates the principle of how the curved screen 8 under test modulates the incident light when inspecting a curved screen using an existing display defect detection system.

[0085] Figure 4b The illustration shows a schematic diagram of the principle of the front illumination mirror 3 converging and modulating incident light in a curved screen defect detection device according to an embodiment of the present invention.

[0086] like Figure 4a As shown, the curved screen 8 to be inspected can be considered as a convex reflector. Because a convex reflector diverges incident light, in existing display defect detection systems, the parallel light beam is reflected by the curved screen 8 and diverged, preventing the reflected light carrying edge point spatial information from being received by the imaging module 1 for image acquisition, thus resulting in missing edge point image information. However, as... Figure 4b As shown, the present invention uses a front illumination mirror 3 with positive focal length, so that the incident light emitted by the light source module 5 is first converged and modulated by the front illumination mirror 3 before being incident on the curved screen 8 to be tested, thereby reducing the exit angle of the reflected light after being reflected by the curved screen 8 to be tested, and avoiding the loss of edge point image information.

[0087] Figure 5 The diagram illustrates the principle of compensating for the emission angle of reflected light from the front illumination mirror 3 in a curved screen defect detection device according to an embodiment of the present invention.

[0088] like Figure 5 As shown, the center of the circle corresponding to the radius of curvature of the curved screen 8 to be tested is the image-side focal point of the current illumination mirror 3. Figure 5 When the centers (O in the diagram represent the center of the circle) coincide, the illumination beam emitted by the light source module 5 passes through the front illumination mirror 3 and then strikes the curved screen 8 to be tested. Since the illumination beam with a certain angle converges after passing through the front illumination mirror 3, the angle between the incident light beam at each point on the curved screen 8 and the normal at that point is also very small, thereby reducing the exit angle of the reflected light at each point on the curved screen 8.

[0089] In some embodiments, the focal length of the front illumination mirror 3 is calculated based on the radius of curvature of the curved screen 8 to be tested and the working distance, wherein the working distance is the distance between the front illumination mirror 3 and the curved screen 8 to be tested.

[0090] In some embodiments, the specific formula for calculating the focal length of the front illumination mirror 3 is as follows:

[0091] f′=L+R,

[0092] Where f′ represents the focal length of the front illumination mirror 3, L represents the working distance, that is, the distance between the front illumination mirror 3 and the curved screen 8 to be tested, and R represents the radius of curvature of the curved screen 8 to be tested.

[0093] It should be noted that when the radius of curvature of the curved screen 8 to be tested is R, if the focal length of the front illumination lens 3 is f′, then the working distance between the front illumination lens 3 and the curved screen 8 to be tested should be maintained at L = f′ - R. The above scheme allows for flexible selection of front illumination lenses 3 with different focal lengths and corresponding working distances based on the radius of curvature of the curved screen 8 to be tested, thus achieving illumination pupil matching. The specific values ​​of the focal length or working distance of the front illumination lens 3 can be determined by considering the actual application scenario and using the above calculation formula. This invention does not impose specific limitations on the focal length or working distance of the front illumination lens 3.

[0094] In some embodiments, such as Figure 2 As shown, the imaging module 1 includes an imaging objective lens 10 and a line scan camera 11;

[0095] The imaging objective lens 10 and the line scan camera 11 are detachably connected.

[0096] The imaging objective lens 10 is positioned on the side close to the beam splitter 2.

[0097] To ensure that the reflected light from the upper edge of the curved screen 8 is received by the subsequent imaging module 1 as much as possible, the focusing ability of the front illumination mirror 3 should be close to the astigmatism ability of the curved screen 8, i.e., the focal length of the front illumination mirror 3 should be close to the radius of curvature of the curved screen 8. However, when the above conditions are met, the working distance L between the front illumination mirror 3 and the curved screen 8 will be very small. The reflected light from the upper edge of the curved screen 8 will pass through the front illumination mirror 3 and the subsequent imaging module 10 in sequence. Therefore, the front illumination mirror 3 in this invention participates in both the initial illumination light path modulation and the subsequent imaging light path.

[0098] Furthermore, since defect detection of curved screens is generally a streamlined process, the distance between each curved screen 8 to be inspected and the curved screen defect detection device will vary within a certain range. Moreover, due to the large curvature of the curved screen 8 to be inspected, the distance between different points on the curved screen 8 and the curved screen defect detection device will also vary. Therefore, the imaging objective lens 10 in the subsequent imaging module 1 needs to have a certain depth of field.

[0099] In some embodiments, the depth-of-field calculation formula for the imaging objective lens 10 is as follows;

[0100]

[0101] Where ΔL represents the depth of field of the imaging objective 10, F represents the number of image planes of the imaging objective 10, δ represents the minimum image plane resolution of the line scan camera 11, f′ represents the focal length of the front illumination mirror 3, and L represents the working distance, that is, the distance between the front illumination mirror 3 and the curved screen 8 to be tested.

[0102] In some embodiments, the minimum image resolution of the curved screen defect detection device is specifically calculated using the following formula:

[0103] δ min =1.22λF,

[0104] Where, δ min λ represents the minimum image resolution of the curved screen defect detection device, λ represents the wavelength of the illumination source in the light source module 5, and F represents the image number of the imaging objective lens 10.

[0105] Assuming the system magnification of the imaging objective lens 10 is β, when the minimum resolution required by the curved screen 8 to be detected, i.e., the object-space resolution, is δ0, the formula for calculating the minimum image-space resolution δ required by the line scan camera 11 is as follows:

[0106] δ=δ0×β.

[0107] Furthermore, the system magnification of the imaging objective 10 can also be calculated based on the size of the detection surface of the line scan camera 11 and the size of the curved screen 8 to be detected; or based on the focal length of the front illumination mirror 3 and the number of image squares of the imaging objective 10, as shown in the following formula:

[0108]

[0109] Where β represents the system magnification of the imaging objective lens 10, y′ represents the size of the detection surface of the linear array camera 11, y represents the size of the curved screen 8 to be detected, f′ represents the focal length of the front illumination mirror 3, and L represents the working distance, that is, the distance between the front illumination mirror 3 and the curved screen 8 to be detected.

[0110] In some embodiments, according to the above calculation formula, the depth of field of the imaging objective lens 10 and the minimum image resolution of the curved screen defect detection device are negatively correlated.

[0111] In some embodiments, such as Figure 2 As shown, a curved screen defect detection device also includes a control module 9, which is communicatively connected to the light source module 5, the imaging module 1 and the defect detection module 7.

[0112] Among them, control module 9 is used for:

[0113] When the light source module 5 is turned on, the control imaging module 1 acquires the image of the curved screen to be detected, which includes the spatial information of all points on the curved screen 8 to be detected.

[0114] The defect detection module 7 controls the defect detection of the curved screen image to be inspected;

[0115] Based on the defect detection results, determine whether the curved screen 8 to be tested needs to be rejected.

[0116] It should be noted that in this invention, the defect detection module 7 and the control module 9 are both located on the same server (not shown in the figure), and are distinguished only by their different functions.

[0117] Furthermore, in all the accompanying drawings of this invention, except for special markings and descriptions, the lines with arrows represent incident or reflected light rays. For details, please refer to the light path direction, imaging direction or corresponding markings in each drawing. Therefore, the lines with arrows in the drawings mainly refer to incident or reflected light rays, which will not make the solution of this invention unclear.

[0118] Figure 7 A flowchart of a method for detecting defects in a curved screen according to another embodiment of the present invention is shown as an example.

[0119] In other embodiments, such as Figure 7 As shown, the present invention provides a method for detecting defects in curved screens, implemented based on a curved screen defect detection device according to an embodiment of the present invention. The method includes the following steps:

[0120] 100, control the light source module 5 to turn on;

[0121] 101. While the light source module 5 is turned on, the imaging module 1 is controlled to acquire the image of the curved screen to be tested. The image of the curved screen to be tested includes the spatial information of all points on the curved screen to be tested 8. The curved screen to be tested 8 is designed as a curved cylindrical structure.

[0122] 102. Receive the image of the curved screen to be inspected and perform defect detection on it;

[0123] 103. Based on the defect detection results, determine whether the curved screen 8 to be inspected needs to be rejected.

[0124] It should be noted that the defect detection process for the curved screen image to be tested in this invention is the same as the detection process in the prior art, and the rejection process is also the same as the rejection process in the prior art, so it will not be described again here. In addition, this invention does not limit the material of the curved screen 8 to be tested. The defect detection scheme of this invention can be applied to any curved surface made of one or more of the following materials: glass, crystal, metal, or plastic.

[0125] This invention, by setting a front illumination mirror 3 between the placement platform 6 and the beam splitter 2, further utilizes the front illumination mirror 3 to converge and modulate the reflected light after it has passed through the curved screen 8 to be tested, thereby reducing the exit angle of the reflected light and thus avoiding the loss of spatial information of the upper edge points of the curved screen 8 to be tested; furthermore, by using the front illumination mirror 3 in both the illumination optical path and the imaging optical path, the integration of the curved screen defect detection device can be improved.

[0126] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the discussion in some embodiments above is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the embodiments and various different variations of the embodiments suitable for specific application considerations.

Claims

1. A defect detection device for curved screens, characterized in that, include: Imaging module, beam splitter, positive optical power front illumination mirror, illumination collimating mirror, light source module, and placement platform, as well as defect detection module; The imaging module is disposed on one side of the beam splitter, and the center of the imaging module and the center of the beam splitter are located on the same central axis in the horizontal direction. The front illumination mirror is disposed on the other side of the beam splitter, and the center of the front illumination mirror and the center of the beam splitter are arranged on the same horizontal central axis. The front illumination mirror is used to converge the incident light rays and direct them onto the curved screen to be tested, and to compensate for the exit angle of the light rays reflected from the curved screen to be tested. The front illumination mirror includes a first positive lens and a second positive lens, wherein the centers of the first positive lens and the second positive lens are arranged on the same horizontal central axis; the first positive lens is disposed on the side closer to the placement platform; the second positive lens is disposed on the side closer to the beam splitter. The center of the illumination collimating lens and the center of the beam splitter are on the same vertical central axis; The light source module is located on the side of the illumination collimating lens away from the beam splitter, and the center of the light source module and the center of the illumination collimating lens are on the same central axis in the vertical direction. The placement platform is located on the side of the front illumination mirror away from the beam splitter. The placement platform is used to place the curved screen to be tested, and the curved screen to be tested is designed as a curved cylindrical structure. The defect detection module is communicatively connected to the imaging module. The defect detection module is used to perform defect detection on the curved screen image to be detected acquired by the imaging module and output the detection result.

2. The curved screen defect detection device according to claim 1, characterized in that, The focal length of the front illumination mirror is calculated based on the radius of curvature of the curved screen to be tested and the working distance, wherein the working distance is the distance between the front illumination mirror and the curved screen to be tested.

3. The curved screen defect detection device according to claim 2, characterized in that, The focal length of the front illumination mirror is calculated using the following formula: f' = L + R Where f' represents the focal length of the front illumination mirror, L represents the working distance, and R represents the radius of curvature of the curved screen to be tested.

4. The curved screen defect detection device according to claim 1, characterized in that, The imaging module includes an imaging objective lens and a line scan camera; The imaging objective lens and the line scan camera are connected. The imaging objective lens is positioned on the side closest to the beam splitter.

5. The curved screen defect detection device according to claim 4, characterized in that, The depth of field of the imaging objective lens is calculated using the following formula: Where ΔL represents the depth of field of the imaging objective, F represents the image square number of the imaging objective, δ represents the minimum image square resolution of the line scan camera, f' represents the focal length of the front illumination lens, and L represents the working distance.

6. A curved screen defect detection device according to any one of claims 1-5, characterized in that, The depth of field of the imaging objective lens is negatively correlated with the minimum image resolution of the curved screen defect detection device.

7. The curved screen defect detection device according to claim 6, characterized in that, The minimum image resolution of the curved screen defect detection device is calculated using the following formula: d min =1.22λF, Where, δ min λ represents the minimum image resolution of the curved screen defect detection device, λ represents the wavelength of the illumination source in the light source module, and F represents the image number of the imaging objective lens.

8. The curved screen defect detection device according to claim 1, characterized in that, The curved screen defect detection device also includes a control module, which is communicatively connected to the light source module, the imaging module and the defect detection module respectively. The control module is used for: When the light source module is turned on, the imaging module is controlled to acquire an image of the curved screen to be detected, and the image of the curved screen to be detected includes spatial information of all points on the curved screen to be detected; The defect detection module is controlled to perform defect detection on the curved screen image to be detected. Based on the defect detection results, determine whether the curved screen to be tested needs to be rejected.

9. A method for detecting defects in a curved screen, characterized in that, Applied in a curved screen defect detection device as described in any one of claims 1-8, the curved screen defect detection method includes: Turn on the control light source module; While the light source module is turned on, the imaging module is controlled to acquire an image of the curved screen to be tested. The image of the curved screen to be tested includes spatial information of all points on the curved screen to be tested. The curved screen to be tested is designed as a curved cylindrical structure. Receive the image of the curved screen to be detected and perform defect detection on it; Based on the defect detection results, determine whether the curved screen to be tested needs to be rejected.

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