Backlight module display viewing angle uniformity detection device and method

Abstract

The present application relates to backlight module display viewing angle uniformity detection device and method, the device includes: rack and image acquisition component;Image acquisition component includes support frame, a plurality of arc-shaped adjusting plates, main viewing angle camera and a plurality of inclination angle cameras, main viewing angle camera is set on support frame, and is aligned with module tooling fixture in vertical direction, each arc-shaped adjusting plate is connected with support frame respectively, and each arc-shaped adjusting plate is arranged with the center axis of the shooting viewing angle of main viewing angle camera as the center around main viewing angle camera equal angle;Each inclination angle camera is set on camera mounting plate, each camera mounting plate is slidably arranged on arc-shaped adjusting plate, and the sliding track of each inclination angle camera on arc-shaped adjusting plate is arc-shaped. By setting arc-shaped adjusting plate, the inclination angle camera can be arc-shaped movement along the arc-shaped adjusting plate, the angle of the backlight module to be measured is adjusted, and the detection of different light-emitting viewing angles of the backlight module to be measured is realized.

Description

Technical Field

[0001] This invention relates to the field of backlight testing technology, and in particular to a device and method for detecting the uniformity of viewing angle of a backlight module display. Background Technology

[0002] A vehicle-mounted PHUD (Panoramic Head-Up Display) backlight system is a smart cockpit technology that projects driving information, such as vehicle speed and navigation information, onto the black area along the lower edge of the windshield, providing a panoramic view from A-pillar to A-pillar, reducing driver distraction and improving driving safety. Currently, with the continuous development of automotive intelligence, vehicle-mounted PHUDs are widely used.

[0003] Before leaving the factory, PHUD backlight systems require testing of the backlight effect of the backlight modules, including backlight uniformity and backlight display angle. Specifically, backlight display angle testing involves capturing images of the backlight module emitting light at different angles. Current equipment can only perform tilt angle testing on a single side of the backlight module and cannot perform multi-directional tilt angle testing. Summary of the Invention

[0004] Therefore, it is necessary to provide a device and method for detecting the uniformity of the display viewing angle of a backlight module.

[0005] A backlight module display viewing angle uniformity detection device includes: a frame and an image acquisition component;

[0006] The frame has a testing platform, on which module tooling fixtures are provided; The image acquisition component includes a support frame, multiple arc-shaped adjustment plates, a main-view camera, and multiple tilt cameras. The support frame is mounted on the detection platform, and the main-view camera is mounted on the support frame and aligned vertically with the module tooling fixture. The main-view camera's shooting direction faces the module tooling fixture. Each arc-shaped adjustment plate is connected to the support frame. Each arc-shaped adjustment plate is set at an equal angle around the main-view camera with the central axis of the main-view camera's shooting angle as its center. Each arc-shaped adjustment plate coincides with a radius of a circle centered on the central axis of the main-view camera's shooting angle. Each tilt camera is mounted on a camera mounting plate, and each camera mounting plate is slidably mounted on the arc-shaped adjustment plate. The sliding trajectory of each tilt camera on the arc-shaped adjustment plate is arc-shaped, and the shooting direction of each tilt camera points to the center of the arc. The center of the arc is located on the module tooling fixture.

[0007] In one embodiment, each of the arc-shaped adjustment plates is provided with an arc-shaped groove, the center of which is located on the module tooling fixture, and the camera mounting plate slides along the arc-shaped groove.

[0008] In one embodiment, the camera mounting plate is provided with a sliding shaft, which is slidably disposed within the arc-shaped groove.

[0009] In one embodiment, each camera mounting plate is provided with two guide shafts, and each arc-shaped adjustment plate is provided with arc-shaped guide grooves on both sides of the arc-shaped slide groove. The two guide shafts are respectively arranged in the two arc-shaped guide grooves, and the center of the arc-shaped guide groove on the same arc-shaped adjustment plate coincides with the center of the arc-shaped slide groove.

[0010] In one embodiment, each camera mounting plate includes a mounting plate body and a locking assembly. The tilt camera is mounted on the mounting plate body. The locking assembly includes a clamping member, an eccentric wheel, and a connecting member. The mounting plate body is located on one side of the arc-shaped adjustment plate, and the clamping member is located on the other side of the arc-shaped adjustment plate. The clamping member is provided with a support shaft. One end of the connecting member is connected to the mounting plate body, and the other end of the connecting member passes through the arc-shaped groove and is connected to the support shaft. The side of the clamping member facing away from the mounting plate body is provided with a rotating groove. The rotating groove is concentrically arranged with the support shaft. The eccentric wheel is rotatably mounted on the support shaft and rotatably disposed within the rotating groove. The outer surface of the eccentric wheel abuts against the sidewall of the rotating groove.

[0011] In one embodiment, a rubber pad is provided on the side of the clamping member facing the arc-shaped adjustment plate.

[0012] In one embodiment, a lighting lamp is also included, which is disposed on the support frame and the light emission direction of the lighting lamp is towards the module tooling fixture.

[0013] A method for detecting the uniformity of the display viewing angle of a backlight module, applied to the backlight module display viewing angle uniformity detection device described in any of the above embodiments, characterized in that each tilt camera of the backlight module display viewing angle uniformity detection device is provided with an angle sensor, the angle sensor is used to obtain the tilt angle of the tilt camera, and the backlight module display viewing angle uniformity detection device includes four arc-shaped adjustment plates, adjacent arc-shaped adjustment plates are perpendicular to each other, opposite arc-shaped adjustment plates are aligned with each other, and a tilt camera is slidably disposed on each arc-shaped adjustment plate. The method includes the following steps: The backlight module is captured using the main-view camera to obtain a reference image; Images of the backlight module are acquired using each of the tilt cameras to obtain distorted images; The tilt angle, rotation radius, and camera intrinsic parameters of each tilt camera are obtained. Based on the coordinates of the main view camera and the size of the backlight module, the homography matrix corresponding to each tilt camera is calculated using the tilt angle, rotation radius, and camera intrinsic parameters of each tilt camera. The distorted image is subjected to perspective transformation using the homography matrix to obtain a corrected image; The corrected image is compared with the reference image to obtain the detection result.

[0014] In one embodiment, after the step of comparing the corrected image with the reference image to obtain the detection result, the method further includes: Perspective transformation is performed on the distorted images acquired by the same tilt camera at at least three different tilt angles to obtain three corrected images, wherein the difference between any two of the three different tilt angles is greater than a preset angle difference, and the preset angle difference is related to the brightness of the backlight module. The three corrected images are compared one by one with the reference image to obtain three sets of similarity matrices; Based on the three sets of similarity matrices and the corresponding three tilt angles, the three similarity matrices are fitted to obtain an angle display change model that reflects the change in display quality with the tilt angle. Based on the angle display change model and the preset display quality threshold, the maximum viewing angle is determined.

[0015] In one embodiment, the step of comparing the three corrected images with the reference image one by one to obtain three sets of similarity matrices includes: The brightness of the three distorted images of each tilt camera and the brightness of the reference image are obtained. The brightness of the three distorted images is compared with the brightness of the reference image one by one to obtain the tilt angle range of sudden brightness drop. The three tilt angles of each tilt camera are not equal. Obtain the pixel parameters of the three corrected images and the pixel parameters of the reference image from the same tilt camera, and compare the pixel parameters of the three corrected images with the pixel parameters of the reference image one by one to obtain three sets of similarity matrices. The step of fitting the three similarity matrices based on the three sets of similarity matrices and the corresponding three tilt angles to obtain an angle display variation model that reflects the display quality as a function of the tilt angle includes: Based on the three sets of similarity matrices and the corresponding three tilt angles, the three similarity matrices are fitted to obtain an initial angle display change model; Based on the division of tilt angles according to the brightness drop angle range, the tilt angle and the corresponding display quality of the initial angle display change model are weighted to obtain the angle display change model.

[0016] The beneficial effects of this invention are: by capturing orthogonal images of the backlight module under test using a main-view camera, and by setting up an arc-shaped adjustment plate, the tilt camera can move in an arc along the arc-shaped adjustment plate to adjust the angle relative to the backlight module under test, thereby realizing the detection of different light emission angles of the backlight module under test, effectively improving the detection efficiency and accuracy of the backlight module. Furthermore, by setting up multiple arc-shaped adjustment plates, multi-directional tilt display detection is also achieved. Attached Figure Description

[0017] 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a three-dimensional structural schematic diagram of a backlight module display viewing angle uniformity detection device according to an embodiment; Figure 2 This is a partial three-dimensional structural schematic diagram of a backlight module display viewing angle uniformity detection device according to an embodiment. Figure 3 A three-dimensional structural diagram of an arc-shaped adjustment plate and a tilt camera in one direction is shown in one embodiment. Figure 4 This is a three-dimensional structural diagram of the arc-shaped adjustment plate and tilt camera from another direction, representing one embodiment. Figure 5 This is a three-dimensional exploded view of an embodiment of the arc-shaped adjustment plate and the tilt camera; Figure 6 This is a partial structural schematic diagram of a backlight module display viewing angle uniformity detection device according to an embodiment; Figure 7 This is a flowchart illustrating a method for detecting the uniformity of viewing angle of a backlight module according to one embodiment.

[0019] Explanation of reference numerals in the attached figures: 10. Backlight module display viewing angle uniformity testing device; 100. Frame; 200. Image acquisition component; 300. Module tooling fixture; 110. Testing table; 210. Support frame; 220. Arc-shaped adjustment plate; 230. Main viewing angle camera; 240. Tilt camera; 250. Camera mounting plate; 221. Arc-shaped slide groove; 222. Arc-shaped guide groove; 251. Sliding shaft; 252. Guide shaft; 253. Mounting plate body; 260. Locking component; 261. 262. Clamping component; 263. Eccentric wheel; 264. Connecting component; 265. Support shaft; 266. Rotating groove; 267. Rubber pad; 268. Handle; 211. Eccentric wheel body; 212. First support column; 213. Second support column; 214. First crossbeam; 215. Second crossbeam; 271. Rectangular frame; 272. Fixing column; 273. Connecting frame; 274. Fixing hole; 275. Clamping groove; 276. Tightening hole; 400. Lighting lamp; Detailed Implementation The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1 and Figure 2 As shown, in one embodiment, a backlight module display viewing angle uniformity detection device 10 is provided, including a frame 100 and an image acquisition component 200; The frame 100 has a testing platform 110, on which a module tooling fixture 300 is provided; The image acquisition component 200 includes a support frame 210, multiple arc-shaped adjustment plates 220, a main-view camera 230, and multiple tilt cameras 240. The support frame 210 is mounted on the detection table 110. The main-view camera 230 is mounted on the support frame 210 and is vertically aligned with the module tooling fixture 300. The shooting direction of the main-view camera 230 faces the module tooling fixture 300. Each arc-shaped adjustment plate 220 is connected to the support frame 210. Each arc-shaped adjustment plate 220 is arranged at equal angles around the main-view camera 230 with the central axis of the shooting angle of the main-view camera 230 as the center. Each arc-shaped adjustment plate 220 coincides with a radius of a circle with the central axis of the shooting angle of the main-view camera 230 as the center. Each tilt camera 240 is mounted on a camera mounting plate 250, and each camera mounting plate 250 is slidably mounted on the arc-shaped adjustment plate 220. The sliding trajectory of each tilt camera 240 on the arc-shaped adjustment plate 220 is arc-shaped, and the shooting direction of each tilt camera 240 points to the center of the arc. The circle containing the arc is perpendicular to the horizontal plane, and the center of the arc is located on the module tooling fixture 300.

[0021] In this embodiment, the testing platform 110 is placed horizontally, and the module fixture 300 is set on the testing platform 110. The module fixture 300 is used to place the backlight module to be tested. The support frame 210 is used to support the main view camera 230 and the arc adjustment plate 220. The main view camera 230 is located directly above the module fixture 300 and takes pictures of the display mold to be tested on the module fixture 300 from top to bottom. Each arc adjustment plate 220 is arranged radially with the central axis of the shooting angle of the main view camera 230 as the center. In each embodiment, the circle with the central axis of the shooting angle of the main view camera 230 as the center is defined as the main view circle. Each arc adjustment plate 220 corresponds to a radius of the main view circle, and the length, curvature, and shape of each arc adjustment plate 220 are equal. The included angle between any two adjacent arc adjustment plates 220 is equal. Each tilt camera 240 is slidably mounted on the arc-shaped adjustment plate 220 via the camera mounting plate 250. The movement trajectory of each tilt camera 240 on the arc-shaped adjustment plate 220 is arc-shaped, and the center of the arc is located on the backlight module to be tested on the module tooling fixture 300. In this way, each tilt camera 240 can be arbitrarily adjusted on the arc-shaped adjustment plate 220 to adjust its angle relative to the backlight module to be tested. Moreover, at any angle, the shooting direction of the tilt camera 240 is always facing the backlight module to be tested on the module tooling fixture 300.

[0022] In this embodiment, the main view camera 230 is used to face the backlight module under test and capture an orthogonal image (front view) of the backlight module under test. The tilt camera 240 is used to tilt the backlight module under test and capture a tilted image of the backlight module under test. In this way, the computer analyzes the orthogonal image and the tilted image to detect the light emission display effect of the backlight module under test from different angles.

[0023] In the above embodiments, the main view camera 230 captures orthogonal images of the backlight module under test, and an arc adjustment plate 220 is set so that the tilt camera 240 can move in an arc along the arc adjustment plate 220 to adjust the angle relative to the backlight module under test. This realizes the detection of different light emission angles of the backlight module under test, effectively improving the detection efficiency and accuracy of the backlight module. Furthermore, by setting multiple arc adjustment plates, multi-directional tilt display detection is also realized.

[0024] It is worth mentioning that the number of the arc-shaped adjustment plates 220 can be adjusted according to the testing needs, with each tilt camera 240 corresponding to one arc-shaped adjustment plate 220. For example, there are three arc-shaped adjustment plates 220, with one tilt camera 240 slidably mounted on each arc-shaped adjustment plate 220 via a camera mounting plate 250. Alternatively, there are six arc-shaped adjustment plates 220, with one tilt camera 240 slidably mounted on each arc-shaped adjustment plate 220 via a camera mounting plate 250. In one embodiment, there are four arc-shaped adjustment plates 220. In this embodiment, the light-emitting surface of the backlight module under test is rectangular. Therefore, arc-shaped adjustment plates 220 are respectively set in four directions of the backlight module under test. Adjacent arc-shaped adjustment plates 220 are perpendicular to each other, and opposite arc-shaped adjustment plates 220 are aligned with each other. In this way, images of the backlight module under test can be acquired from the tilt angles in four directions. In one embodiment, among the four arc-shaped adjustment plates 220, the lengths of the two arc-shaped adjustment plates 220 parallel to the long side of the backlight module under test are greater than the lengths of the two arc-shaped adjustment plates 220 parallel to the short side of the backlight module under test. This allows the movement stroke of each tilt camera 240 to match the length of the backlight module under test in each direction, making the detection more accurate.

[0025] To enable the tilt camera to slide on the arc-shaped adjustment plate, in some embodiments, the arc-shaped adjustment plate is provided with an arc-shaped slide rail, and the camera mounting plate is provided with pulleys or sliders. The pulleys or sliders are mounted on the arc-shaped slide rail, and the center of the arc-shaped slide rail is located on the module tooling fixture. In this embodiment, the camera mounting plate is slidably mounted on the arc-shaped guide rail via pulleys or sliders, so that the tilt camera can achieve arc-shaped movement.

[0026] To enable the tilt camera 240 to slide on the arc-shaped adjustment plate 220, in one embodiment, such as Figures 3 to 5 As shown, each of the arc-shaped adjustment plates 220 has an arc-shaped groove 221, the center of which is located on the module tooling fixture 300. The camera mounting plate 250 slides along the arc-shaped groove 221. In this embodiment, by setting the arc-shaped groove 221, the camera mounting plate 250 can slide, allowing the tilt angle to move in an arc shape. Furthermore, the structure of the arc-shaped groove 221 simplifies the structure of the arc-shaped adjustment plate 220.

[0027] In one embodiment, such as Figures 3 to 5 As shown, the camera mounting plate 250 is provided with a sliding shaft 251, which is slidably disposed within the arc-shaped groove 221. In this embodiment, the sliding shaft 251 is cylindrical in shape. By providing the sliding shaft 251, the camera mounting plate 250 can slide more smoothly along the arc-shaped groove 221, making it easier to adjust the position and angle of the tilt camera 240.

[0028] To ensure smoother sliding of the tilt camera 240 and to fix the angle of the tilt camera 240 relative to the camera mounting plate 250, in one embodiment, please refer to... Figures 3 to 5 Each of the camera mounting plates 250 is provided with two guide shafts 252, and each of the arc-shaped adjustment plates 220 is provided with arc-shaped guide grooves 222 on both sides of the arc-shaped slide groove 221. The two guide shafts 252 are respectively arranged in the two arc-shaped guide grooves 222. The center of the arc-shaped guide groove 222 on the same arc-shaped adjustment plate 220 coincides with the center of the arc-shaped slide groove 221.

[0029] In this embodiment, the arc of the arc guide groove 222 on the same arc adjustment plate 220 is equal to the arc of the arc slide groove 221, and the center of the arc guide groove 222 on the same arc adjustment plate 220 and the center of the arc slide groove 221 are located on the module tooling fixture 300. Two guide shafts 252 are slidably disposed within the arc-shaped guide groove 222. The guide shafts 252 are used to limit the angle of the camera mounting plate 250. As a straight line can be determined from two points on a plane, the two guide shafts 252 can determine a direction to prevent the tilt camera 240 from shaking. On the one hand, when the sliding shaft 251 slides along the arc-shaped sliding groove 221, the two guide shafts 252 can limit the camera mounting plate 250 to prevent the tilt camera 240 from shaking. On the other hand, the two guide shafts 252 can limit the angle of the camera mounting plate 250 relative to the arc-shaped adjustment plate 220, so that the shooting direction of the tilt camera 240 is always facing the backlight module under test on the module tooling fixture 300.

[0030] In one embodiment, such as Figure 3 As shown, the arc-shaped adjustment plate 220 is provided with a scale, and the camera mounting plate 250 is provided with an indicator block. In this embodiment, the scale is used to indicate the position or angle of the tilt camera. When the camera mounting plate 250 slides, the indicator block slides accordingly. When the camera mounting plate 250 is fixed, the indicator block is aligned with a scale, thereby displaying the current angle of the tilt camera.

[0031] In order to fix the angle and position of the tilt camera 240 after the tilt camera 240 has been adjusted, in one embodiment, please refer to... Figures 3 to 5Each of the camera mounting plates 250 includes a mounting plate body 253 and a locking assembly 260. The tilt camera 240 is mounted on the mounting plate body 253. The locking assembly 260 includes a clamping member 261, an eccentric wheel 262, and a connecting member 263. The mounting plate body 253 is located on one side of the arc-shaped adjustment plate 220, and the clamping member 261 is located on the other side of the arc-shaped adjustment plate 220. The clamping member 261 is provided with a support shaft 264. One end of the connecting member 263 is connected to... The mounting plate body 253 is connected, and the other end of the connector 263 passes through the arc-shaped slide groove 221 and is connected to the support shaft 264. The clamping member 261 has a rotating groove 265 on the side facing away from the mounting plate body 253. The rotating groove 265 is concentrically arranged with the support shaft 264. The eccentric wheel 262 is rotatably arranged on the support shaft 264 and rotatably arranged in the rotating groove 265. The outer surface of the eccentric wheel 262 abuts against the side wall of the rotating groove 265.

[0032] In this embodiment, the end of the connector 263 away from the mounting plate body 253 passes through the arc-shaped groove 221 and the clamping member 261 and connects to the support shaft 264. After the angle and position of the tilt camera 240 are determined, the eccentric wheel 262 is rotated. Since the center of the eccentric wheel 262 is off-center from its geometric center, the eccentric wheel 262 is supported by the side wall of the rotating groove 265, which drives the support shaft 264 away from the arc-shaped adjustment plate 220, thereby driving the connector 263 to move towards the eccentric wheel 262. The connector 263 drives the mounting plate body 253. The entire assembly is close to and attached to the arc-shaped adjustment plate 220. While the eccentric wheel 262 drives the support shaft 264 away from the arc-shaped adjustment plate 220, it applies force to the clamping member 261 through the side wall of the rotating groove 265, so that the clamping member 261 is tightly attached to the arc-shaped adjustment plate 220. In this way, the mounting plate body 253 and the clamping member 261 are respectively pressed against the two sides of the arc-shaped adjustment plate 220. Through friction, the position of the mounting plate body 253 on the arc-shaped adjustment plate 220 is fixed, thereby fixing the angle and position of the tilt camera 240.

[0033] In order to rotate the eccentric wheel 262, in one embodiment, as... Figure 5 As shown, the eccentric wheel 262 includes an eccentric wheel body 268 and a handle 267. The eccentric wheel body 268 is rotatably mounted on the support shaft 264 and rotatably mounted in the rotating groove 265. The outer surface of the eccentric wheel body 268 abuts against the side wall of the rotating groove 265. The eccentric wheel body 268 and the handle 267 are integrally formed. The handle 267 is connected to one side of the eccentric wheel body 268, and the length of the handle 267 is greater than the diameter of the eccentric wheel 262.

[0034] In this embodiment, the handle 267 and the eccentric wheel body 268 are integrally formed. By turning the handle 267, the eccentric wheel body 268 can be rotated, making the rotation of the eccentric wheel 262 simpler and allowing the user to easily lock the tilt camera 240.

[0035] In one embodiment, the clamping member 261 is provided with a rubber pad 266 on the side facing the arc-shaped adjustment plate 220.

[0036] In this embodiment, the clamping member 261 abuts against the arc-shaped adjustment plate 220 through the rubber pad 266. On the one hand, the rubber pad 266 provides a buffer between the clamping member 261 and the arc-shaped adjustment plate 220, making the contact between the clamping member 261 and the arc-shaped adjustment plate 220 tighter. On the other hand, it can increase the friction between the clamping member 261 and the arc-shaped adjustment plate 220, so that the angle and position of the tilt camera 240 are further fixed.

[0037] In one embodiment, such as Figure 2 As shown, the backlight module display viewing angle uniformity detection device 10 also includes an illumination lamp 400, which is disposed on the support frame 210 and the light emission direction of the illumination lamp 400 is towards the module tooling fixture 300.

[0038] In this embodiment, the height of the illumination lamp 400 on the support frame 210 is less than the height of the main-view camera 230 and each tilt camera 240. This prevents the illumination of the illumination lamp 400 from being blocked by the cameras. Furthermore, it ensures sufficient illumination of the backlight module under test, improving detection accuracy. In this embodiment, the illumination lamp 400 is located outside the shooting angles of the main-view camera 230 and each tilt camera 240, thus preventing the shooting angles from being blocked by the illumination lamp 400.

[0039] In one embodiment, such as Figure 2 As shown, the support frame 210 includes a plurality of first support columns 211, a plurality of second support columns 212, a first crossbeam 213, and a second crossbeam 214. Each first support column 211 is disposed on the detection table 110. The first crossbeam 213 is connected to one end of each first support column 211 away from the detection table 110. Each arc-shaped adjustment plate 220 is connected to the first crossbeam 213. One end of each second support column 212 is disposed on the first crossbeam 213, and the other end of each second support column 212 is connected to the second crossbeam 214. The main view camera 230 is disposed on the second crossbeam 214.

[0040] In this embodiment, there are four first support columns 211, located at the four opposite corners of the detection platform 110. A first horizontal frame 213 is horizontally positioned, supporting the arc-shaped adjustment plate 220. A second horizontal frame 214 is connected to the first horizontal frame 213 via second support columns 212, allowing the second horizontal frame 214 to be spaced apart from the first horizontal frame 213. This ensures that the height of the main-view camera 230 on the second horizontal frame 214 is greater than the height of each tilt camera 240. Notably, in some embodiments, each of the first support columns 211 and each of the second support columns 212 is telescopic, allowing the first horizontal frame 213 and the second horizontal frame 214 to be raised and lowered, thus adjusting the height of the main-view camera 230 and the tilt camera 240.

[0041] In one embodiment, please combine Figure 2 and Figure 6 The support frame 210 further includes a U-shaped frame 271 and a plurality of fixed columns 272. Each fixed column 272 is disposed on the first horizontal frame 213. One end of each fixed column 272 away from the first horizontal frame 213 is connected to the U-shaped frame 271. The U-shaped frame 271 has a hollow structure in the middle. The shooting angle of the main view camera 230 is located inside the hollow structure. The first end of each arc-shaped adjustment plate 220 is connected to the first horizontal frame 213, and the second end of each arc-shaped adjustment plate 220 is connected to the U-shaped frame 271. The projection of each arc-shaped adjustment plate 220 on the detection table 110 is located outside the projection of the hollow structure on the detection table 110.

[0042] In this embodiment, the projection of the main-view camera 230 onto the detection platform 110 is located within the projection of the hollow structure onto the detection platform 110. This allows the main-view camera 230 to capture images of the backlight module under test through the hollow structure, avoiding obstruction of the shooting angle. In this embodiment, the fixing posts 272 are arranged perpendicular to the first horizontal frame 213. For example, there are four fixing posts 272. Two of the four fixing posts 272 are connected to one side of the U-shaped frame 271, and the other two are connected to the other side of the U-shaped frame 271. This allows the U-shaped frame 271 to be fixed on the first horizontal frame 213. In this embodiment, the U-shaped frame 271 is located in the middle of the first horizontal frame 213, and the U-shaped frame 271 is rectangular or square. The U-shaped frame 271 includes four U-shaped sub-frames connected end to end, and the four U-shaped sub-frames are connected to form a U-shape. The first end of each of the arc-shaped adjustment plates 220 is connected to the first crossbeam 213 near its outer edge, and the second end of each of the arc-shaped adjustment plates 220 is connected to the circular frame 271. For example, there are four arc-shaped adjustment plates 220, each connected to one side of the circular frame 271. By setting the circular frame 271, on the one hand, each arc-shaped adjustment plate 220 can be effectively supported, and on the other hand, the shooting angle of the main view camera 230 can be prevented from being blocked, so that the main view camera 230 and each tilt camera 240 do not interfere with each other.

[0043] To secure the ring 271, in one embodiment, such as Figure 6 As shown, the support frame 210 also includes two connecting frames 273 and four fixing posts 272. Each fixing post 272 has a fixing hole 274 at a position away from the first cross frame 213. The side wall of the fixing hole 274 has a clamping groove 275. The clamping groove 275 extends to the end face of the fixing post 272 away from the first cross frame 213. The side walls on both sides of the clamping groove 275 have tightening holes 276. The tightening holes 276 extend to the outer surface of the fixing post 272. One connecting frame 273 passes through the fixing holes 274 of the two fixing posts 272 located on one side of the loop frame 271, and the other connecting frame 273 passes through the fixing holes 274 of the two fixing posts 272 located on the other side of the loop frame 271. One side of the loop frame 271 is connected to one connecting frame 273, and one side of the loop frame 271 is connected to the other connecting frame 273.

[0044] In this embodiment, the two ends of the connecting frame 273 are fixed by two fixing posts 272 respectively. Specifically, after the two ends of the connecting frame 273 are inserted into the fixing holes 274 of the two fixing posts 272 respectively, the screws are screwed into the tightening holes 276, causing the side walls on both sides of the clamping groove 275 to move closer to each other, and causing the side walls of the fixing holes 274 to contract, thereby fixing the two ends of the connecting frame 273. The clamping effect of the screws on the clamping groove 275 can also be achieved by the cooperation of screws and nuts. For example, the screw is inserted from one side of the fixing post 272, and the screw passes through the tightening hole 276 on one side, the clamping groove 275 and the tightening hole 276 on the other side in sequence, and connects to the nut located on the other side of the fixing post 272. As the depth of the screw into the nut increases, the clamping groove 275 shrinks, so that the fixing holes 274 can fully clamp and fix the connecting frame 273.

[0045] In one embodiment, please see again Figure 6 A screw hole is provided on one side of the spiral frame 271, and a connecting hole corresponding to the screw hole is provided on the connecting frame 273. The screw connector passes through the connecting hole and is installed in the screw hole, and is screwed to the side wall of the screw hole. In this way, the connecting frame 273 and the spiral frame 271 can be stably connected by bolts, thereby achieving support and fixation of the spiral frame 271.

[0046] In one embodiment, a method for detecting the uniformity of the display viewing angle of a backlight module is provided. This method is applied to the backlight module display viewing angle uniformity detection device in any of the above embodiments. In this embodiment, each tilt camera of the backlight module display viewing angle uniformity detection device is provided with an angle sensor. The angle sensor is used to obtain the tilt angle of the tilt camera. The backlight module display viewing angle uniformity detection device includes four arc-shaped adjustment plates. Adjacent arc-shaped adjustment plates are perpendicular to each other, and opposite arc-shaped adjustment plates are aligned with each other. A tilt camera is slidably disposed on each arc-shaped adjustment plate. like Figure 7 As shown, the method includes the following steps: Step 510: Use the main view camera to capture images of the backlight module to obtain a reference image; Step 520: Use each tilt camera to acquire images of the backlight module to obtain distorted images; Step 530: Obtain the tilt angle, rotation radius and camera intrinsic parameters of each tilt camera; using the tilt angle, rotation radius and camera intrinsic parameters of each tilt camera, calculate the homography matrix corresponding to each tilt camera based on the coordinates of the main view camera and the size of the backlight module. Step 540: Perform perspective transformation on the distorted image using the homography matrix to obtain a corrected image; Step 550: Compare the corrected image with the reference image to obtain the detection result.

[0047] In this embodiment, the shooting angle of the main-view camera is called the main-view angle, and the central axis of the main-view angle is parallel to the vertical direction. The tilt angle of the tilt camera includes the tilt angle θ relative to the shooting angle of the main-view camera, i.e., the pitch angle, which is the angle between the shooting angle of the tilt camera and the vertical direction. In addition, the tilt angle of the tilt camera also includes the azimuth angle, which is the extension direction of the arc adjustment plate where the tilt camera is located. This azimuth angle can be determined according to the orientation of the arc adjustment plate. Therefore, the azimuth angles φ of the four tilt cameras are 0°, 90°, 180° and 270° respectively. In this embodiment, the camera intrinsic parameters include the focal length f, the principal point (cx, cy), and the rotation radius R of the tilt camera, which is the distance between the center of the circle where the tilt camera slides on the arc adjustment plate. Therefore, the coordinates of the position of the tilt camera on the spherical surface where it rotates are: C i = (Rsinθ cosφ, Rsinθsinφ, Rcosθ).

[0048] The dimensions of the backlight module include length h and width w. The coordinates of the four opposite corners of the backlight module are P1 = (-W / 2, -H / 2, 0), P2 = (W / 2, -H / 2, 0), P3 = (W / 2, H / 2, 0), and P4 = (-W / 2, H / 2, 0). Then, from the perspective of the main view camera, the image coordinates (x, y, 0) of point P=(X, Y, 0) are... v , y v )for: x v =f1X / H+cx1,y v =f1Y / H+cy1 Where H is the height of the main-view camera, f1 is the focal length of the main-view camera, and (cx1, cy1) is the principal point of the main-view camera.

[0049] Then the image coordinates (xi, yi) of point P in the tilt camera are: Pc=R i T (P-C) i ) x i =f2P c x / P c z +cx2,y i =f2P c y / P c z +cy 2， Where f2 is the focal length of the tilt camera, and (cx2, cy2) is the principal point of the tilt camera.

[0050] R i The rotation matrix of the tilt camera is

[0051] P c x P c y P c z It is the coordinate of P in the tilt camera coordinate system.

[0052] Using the above formula, the reference coordinates of the four opposite corners of the backlight module in the reference image of the main view camera are calculated, and the image coordinates of the four opposite corners of the backlight module in the distorted images of each tilt camera are calculated. The linear equation system Ah=0 is solved, where A is a matrix composed of corresponding points and h is the element vector of H, thus obtaining the homography matrix H.

[0053] Subsequently, a perspective transformation is performed on the distorted image using a homography matrix to obtain a corrected image. Specifically, a pixel grid of the same size as the reference image is constructed using the size of the backlight module. The distorted image is analyzed to obtain the pixels of each point in the distorted image. Using a homography matrix, the pixels of each point in the distorted image are mapped to the pixel grid to obtain the corrected image. Then, the corrected image is compared with the reference image to obtain the detection result. In this embodiment, the corrected image and the reference image are compared for image features, including pixel values, pixel mean, pixel standard deviation, signal-to-noise ratio, etc. The pixel values ​​of each pixel in the corrected image are compared one by one with the pixel values ​​of each pixel in the reference image to obtain the detection result.

[0054] It is worth mentioning that, since the backlight module has a fixed light emission direction, it has a maximum viewing angle. This maximum viewing angle is the angle at which the viewing angle reaches its maximum tilt angle while the display effect meets the preset effect. Using the central axis of the main view camera's shooting angle as the orthogonal viewing angle, this tilt angle refers to the angle tilted relative to the central axis of the main view camera's shooting angle. To detect the maximum viewing angle of the backlight module, the tilt angle of the tilt camera needs to be adjusted multiple times. This adjustment is inefficient, as the large steps of manual adjustment lead to large errors and low accuracy. Furthermore, manual adjustments often cannot accurately find the precise maximum viewing angle. To accurately determine the maximum viewing angle, in one embodiment, after the step of comparing the corrected image with the reference image to obtain the detection result, the following is also included: Perspective transformation is performed on the distorted images acquired by the same tilt camera at at least three different tilt angles to obtain three corrected images, wherein the difference between any two of the three different tilt angles is greater than a preset angle difference, and the preset angle difference is related to the brightness of the backlight module. The three corrected images are compared one by one with the reference image to obtain three sets of similarity matrices; Based on the three sets of similarity matrices and the corresponding three tilt angles, the three similarity matrices are fitted to obtain an angle display change model that reflects the change in display quality with the tilt angle. Based on the angle display change model and the preset display quality threshold, the maximum viewing angle is determined.

[0055] In this embodiment, distorted images are acquired at different tilt angles for each tilt camera, and perspective transformation is performed on each image to obtain a corrected image. These corrected images are then compared with a reference image, with comparison parameters including pixel value, pixel mean, pixel standard deviation, grayscale value, and brightness value for each pixel. The comparison results are arranged according to a pixel grid to obtain a similarity matrix. This similarity matrix reflects the degree of similarity between the corrected image and the reference image in terms of various parameters. The three similarity matrices are fitted according to the distribution of the three tilt angles to obtain an angle display variation model. For example, this angle display variation model is an angle display variation curve. Fitting the three similarity matrices according to the distribution of the three tilt angles yields an angle display variation curve reflecting the display quality as the tilt angle changes. This curve reflects the display quality corresponding to different tilt angles, and the display quality is directly proportional to the similarity; the higher the similarity, the higher the display quality. In this embodiment, the tilt angle corresponding to a display quality greater than a preset display quality threshold is determined as the viewing angle, thus determining the maximum viewing angle. After measuring the maximum viewing angle, the tilt camera is manually adjusted to the maximum viewing angle, and the image captured by the tilt camera is inspected to verify the maximum viewing angle. Using the adjustment method in this embodiment reduces the number of times the tilt camera angle needs to be manually adjusted, thus improving inspection efficiency.

[0056] It is worth mentioning that in this embodiment, the tilt camera angle is manually adjusted. To avoid squaring the tilt camera angle and to prevent the distorted images used as samples from being too similar due to two tilt angles being too close, in this embodiment, the difference between any two of the three different tilt angles is greater than a preset angle difference. For example, the difference between the tilt angle of the first test and the tilt angle of the second test is greater than the preset angle difference, and the tilt angle of the second test is greater than the tilt angle of the first test. Similarly, the difference between the tilt angle of the second test and the tilt angle of the third test is greater than the preset angle difference, and the tilt angle of the third test is greater than the tilt angle of the second test. This ensures that the tested tilt angles cover a wider range, resulting in a larger range of tilt angles covered by the distorted images used as samples. Although the number of samples does not increase, the range of tilt angles represented is larger, thereby improving detection accuracy. Furthermore, in this embodiment, the preset angle difference is related to the brightness and size of the backlight module. The greater the brightness of the backlight module, the larger the preset angle difference; similarly, the larger the size of the backlight module, the larger the preset angle difference.

[0057] In one embodiment, the step of comparing the three corrected images with the reference image one by one to obtain three sets of similarity matrices includes: The brightness of the three distorted images of each tilt camera and the brightness of the reference image are obtained. The brightness of the three distorted images is compared with the brightness of the reference image one by one to obtain the tilt angle range of sudden brightness drop. The three tilt angles of each tilt camera are not equal. Obtain the pixel parameters of the three corrected images and the pixel parameters of the reference image from the same tilt camera, and compare the pixel parameters of the three corrected images with the pixel parameters of the reference image one by one to obtain three sets of similarity matrices. The step of fitting the three similarity matrices based on the three sets of similarity matrices and the corresponding three tilt angles to obtain an angle display variation model that reflects the display quality as a function of the tilt angle includes: Based on the three sets of similarity matrices and the corresponding three tilt angles, the three similarity matrices are fitted to obtain an initial angle display change model; Based on the division of tilt angles according to the brightness drop angle range, the tilt angle and the corresponding display quality of the initial angle display change model are weighted to obtain the angle display change model.

[0058] It is worth noting that the display quality does not change linearly with the tilt angle, mainly due to the influence of the backlight brightness of the backlight module. The brightness of the backlight module does not change linearly with the angle; as the shooting angle deviates from vertical, the brightness gradually decreases. This decrease is often non-linear: the brightness change is small within a small angle range, but as the angle continues to increase, the brightness may drop sharply. Therefore, in this embodiment, the brightness of the distorted images acquired at the three tilt angles of each tilt camera is used to calculate the tilt angle range of the sudden brightness drop. On the one hand, the distorted images have not undergone perspective transformation, and their brightness remains in its original state, making the brightness comparison results more accurate and the determination of the tilt angle range of the sudden brightness drop more accurate. On the other hand, since the three tilt angles of each tilt camera are different, the four tilt cameras can acquire distorted images at twelve different tilt angles, thus increasing the number and range of comparisons and thus more accurately determining the tilt angle range of the sudden brightness drop. It is worth noting that the brightness drops sharply with tilt angle, and the range of sharp brightness drops is roughly the same across different orientations. For different tilt cameras, the corresponding tilt angle ranges for sharp brightness drops are roughly the same. Therefore, the tilt angle range for sharp brightness drops can be calculated by combining the distorted images from four tilt cameras. While the maximum viewing angle is affected by brightness variations, it is also influenced by pixel parameters and the dimensions of the backlight module, such as length and width. Therefore, it is not possible to calculate the similarity matrix by combining the pixel parameters of different tilt cameras. Thus, in this embodiment, the pixel parameters of three corrected images from the same tilt camera are compared with the pixel parameters of a reference image to obtain three sets of similarity matrices. Subsequently, when calculating the angle display change model, the three sets of similarity matrices and the corresponding three tilt angles are first used to fit an initial angle display change model that reflects the change in display quality with the tilt angle. Then, the tilt angle range is divided by the tilt angle interval of sudden brightness drop. The display quality of the interval with small brightness change is weighted, while the display quality of the interval with small brightness change is not processed or is reduced accordingly. This makes the angle display change model show a significant decrease or increase in display quality as the angle changes, thus obtaining a more accurate angle display change model.

[0059] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A backlight module display viewing angle uniformity detection device, characterized in that, include: Rack and image acquisition components; The frame has a testing platform, on which module tooling fixtures are provided; The image acquisition component includes a support frame, multiple arc-shaped adjustment plates, a main-view camera, and multiple tilt cameras. The support frame is mounted on the detection platform, and the main-view camera is mounted on the support frame and aligned vertically with the module tooling fixture. The main-view camera's shooting direction faces the module tooling fixture. Each arc-shaped adjustment plate is connected to the support frame. Each arc-shaped adjustment plate is set at an equal angle around the main-view camera with the central axis of the main-view camera's shooting angle as its center. Each arc-shaped adjustment plate coincides with a radius of a circle centered on the central axis of the main-view camera's shooting angle. Each tilt camera is mounted on a camera mounting plate, and each camera mounting plate is slidably mounted on the arc-shaped adjustment plate. The sliding trajectory of each tilt camera on the arc-shaped adjustment plate is arc-shaped, and the shooting direction of each tilt camera points to the center of the arc. The center of the arc is located on the module tooling fixture.

2. The backlight module display viewing angle uniformity detection device according to claim 1, characterized in that, Each of the arc-shaped adjustment plates is provided with an arc-shaped sliding groove, the center of which is located on the module tooling fixture, and the camera mounting plate slides along the arc-shaped sliding groove.

3. The backlight module display viewing angle uniformity detection device according to claim 2, characterized in that, The camera mounting plate is provided with a sliding shaft, which is slidably disposed within the arc-shaped groove.

4. The backlight module display viewing angle uniformity detection device according to claim 2, characterized in that, Each of the camera mounting plates is provided with two guide shafts, and each of the arc-shaped adjustment plates is provided with arc-shaped guide grooves on both sides of the arc-shaped slide groove. The two guide shafts are respectively set in the two arc-shaped guide grooves one to one, and the center of the arc-shaped guide groove on the same arc-shaped adjustment plate coincides with the center of the arc-shaped slide groove.

5. The backlight module display viewing angle uniformity detection device according to claim 2, characterized in that, Each of the aforementioned camera mounting plates includes a mounting plate body and a locking assembly. The tilt camera is mounted on the mounting plate body. The locking assembly includes a clamping member, an eccentric wheel, and a connecting member. The mounting plate body is located on one side of the arc-shaped adjustment plate, and the clamping member is located on the other side of the arc-shaped adjustment plate. The clamping member is provided with a support shaft. One end of the connecting member is connected to the mounting plate body, and the other end of the connecting member passes through the arc-shaped groove and is connected to the support shaft. The side of the clamping member facing away from the mounting plate body is provided with a rotating groove. The rotating groove is concentrically arranged with the support shaft. The eccentric wheel is rotatably mounted on the support shaft and rotatably disposed within the rotating groove. The outer surface of the eccentric wheel abuts against the side wall of the rotating groove.

6. The backlight module display viewing angle uniformity detection device according to claim 5, characterized in that, A rubber pad is provided on the side of the clamping member facing the arc-shaped adjustment plate.

7. The backlight module display viewing angle uniformity detection device according to claim 1, characterized in that, It also includes a lighting lamp, which is mounted on the support frame and the light emission direction of the lighting lamp is towards the module tooling fixture.

8. A method for detecting the uniformity of viewing angle of a backlight module, applied to the backlight module viewing angle uniformity detection device according to any one of claims 1-7, characterized in that, Each tilt camera in the backlight module display viewing angle uniformity detection device is provided with an angle sensor. The angle sensor is used to obtain the tilt angle of the tilt camera. The backlight module display viewing angle uniformity detection device includes four arc-shaped adjustment plates. Adjacent arc-shaped adjustment plates are perpendicular to each other, and opposite arc-shaped adjustment plates are aligned with each other. Each arc-shaped adjustment plate is slidably arranged with a tilt camera. The method includes the following steps: The backlight module is captured using the main-view camera to obtain a reference image; Images of the backlight module are acquired using each of the tilt cameras to obtain distorted images; The tilt angle, rotation radius, and camera intrinsic parameters of each tilt camera are obtained. Based on the coordinates of the main view camera and the size of the backlight module, the homography matrix corresponding to each tilt camera is calculated using the tilt angle, rotation radius, and camera intrinsic parameters of each tilt camera. The distorted image is subjected to perspective transformation using the homography matrix to obtain a corrected image; The corrected image is compared with the reference image to obtain the detection result.

9. The method for detecting the uniformity of display viewing angle of a backlight module according to claim 8, characterized in that, After the step of comparing the corrected image with the reference image to obtain the detection result, the method further includes: Perspective transformation is performed on the distorted images acquired by the same tilt camera at at least three different tilt angles to obtain three corrected images, wherein the difference between any two of the three different tilt angles is greater than a preset angle difference, and the preset angle difference is related to the brightness of the backlight module. The three corrected images are compared one by one with the reference image to obtain three sets of similarity matrices; Based on the three sets of similarity matrices and the corresponding three tilt angles, the three similarity matrices are fitted to obtain an angle display change model that reflects the change in display quality with the tilt angle. Based on the angle display change model and the preset display quality threshold, the maximum viewing angle is determined.

10. The method for detecting the uniformity of viewing angle of a backlight module according to claim 9, characterized in that, The step of comparing the three corrected images with the reference image one by one to obtain three sets of similarity matrices includes: The brightness of the three distorted images of each tilt camera and the brightness of the reference image are obtained. The brightness of the three distorted images is compared with the brightness of the reference image one by one to obtain the tilt angle range of sudden brightness drop. The three tilt angles of each tilt camera are not equal. Obtain the pixel parameters of the three corrected images and the pixel parameters of the reference image from the same tilt camera, and compare the pixel parameters of the three corrected images with the pixel parameters of the reference image one by one to obtain three sets of similarity matrices. The step of fitting the three similarity matrices based on the three sets of similarity matrices and the corresponding three tilt angles to obtain an angle display variation model that reflects the display quality as a function of the tilt angle includes: Based on the three sets of similarity matrices and the corresponding three tilt angles, the three similarity matrices are fitted to obtain an initial angle display change model; Based on the division of tilt angles according to the brightness drop angle range, the tilt angle and the corresponding display quality of the initial angle display change model are weighted to obtain the angle display change model.

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