A light guide plate defect visual detection device

Abstract

The present invention provides a light guide plate defect visual inspection device, comprising a frame, a conveying unit and an image acquisition unit, wherein the image acquisition unit comprises an upper line scan camera, a lower line scan camera, a line scan light source, an upper sliding bracket, a lower sliding bracket and a light source bracket; the upper line scan camera is used to collect the front image of the light guide plate from above the image acquisition position, and the scanning direction of the upper line scan camera is perpendicular to the front of the light guide plate; the lower line scan camera is used to collect the back image of the light guide plate from below the image acquisition position, and the scanning direction of the lower line scan camera forms an angle with the back of the light guide plate; the line scan light source is used to irradiate the back of the light guide plate from below the image acquisition position, and the irradiation direction of the line scan light source forms an angle with the back of the light guide plate. The present invention realizes comprehensive capture of internal and external defects of the light guide plate through the multi-angle coordinated configuration of the upper line scan camera, the lower line scan camera and the adjustable light source, and improves the detection adaptability of light guide plates of different materials and thicknesses.

Description

Technical Field

[0001] The invention relates to a light guide plate detection device, in particular to a light guide plate defect visual detection device, and belongs to the technical field of light guide plate detection. Background Art

[0002] A light guide plate is a component made of optical-grade acrylic or PC sheets. By using laser engraving, V-shaped cross grid engraving or UV screen printing technology on its bottom surface, light guide points of high-tech materials with extremely high refractive index and no light absorption are formed. The function of these light guide points is to capture the light emitted from the light source, make it stay on the surface of the sheet, and reflect and diffuse through the light guide points. When the light hits the light guide points, the reflected light will spread in all directions and eventually be evenly emitted from the front of the light guide plate. The density of the light guide plate and the design of light guide points of different sizes ensure the uniform distribution and efficient use of light. During the manufacturing and transportation of light guide plates, various factors may cause product defects. For example, poor material quality, production process errors, imperfect processes, and physical damage and contamination during transportation may cause scratches, bends, deformations or stains on the light guide plate. Traditional detection methods mainly rely on manual observation of surface defects of light guide plates to evaluate their quality. Although this method is simple and fast, and suitable for a small number of rapid detections, it may be affected by subjective factors and may have the risk of missed detection. Summary of the invention

[0003] Based on the above background, the purpose of the present invention is to provide a visual inspection device for light guide plate defects, which realizes the simultaneous inspection of the front and back surfaces of the light guide plate and the comprehensive capture of internal and external defects through the multi-angle collaborative configuration of the upper line scanning camera, the lower line scanning camera and the adjustable light source, thereby improving the inspection adaptability and reliability of light guide plates of different materials and thicknesses.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] A light guide plate defect visual inspection device comprises a frame, a conveying unit and an image acquisition unit, wherein the conveying unit is installed on the top of the frame, and is used to convey the light guide plate to move relative to the frame and pass through an image acquisition position, and the image acquisition unit comprises an upper line scanning camera, a lower line scanning camera, a line scanning light source, an upper sliding bracket, a lower sliding bracket and a light source bracket; the bottom of the upper sliding bracket is fixedly connected to the top of the frame, and the upper line scanning camera is slidably arranged on the top of the upper sliding bracket, and the upper line scanning camera is used to collect a front image of the light guide plate from above the image acquisition position, and the scanning direction of the upper line scanning camera is perpendicular to the front of the light guide plate The lower sliding bracket is arranged at the lower part of the frame, and the inclination angle of the lower sliding bracket relative to the frame is adjustable, the lower line-scan camera is slidably arranged on the top of the lower sliding bracket, the lower line-scan camera is used to collect the back image of the light guide plate from below the image collection position, and the scanning direction of the lower line-scan camera forms an angle with the back of the light guide plate; the light source bracket is arranged at the lower part of the frame, the line-scan light source is arranged on the light source bracket, and the inclination angle of the line-scan light source relative to the light source bracket is adjustable, the line-scan light source is used to irradiate the back of the light guide plate from below the image collection position, and the irradiation direction of the line-scan light source forms an angle with the back of the light guide plate.

[0006] Preferably, the upper sliding bracket is a gantry-type bracket having a crossbeam, the crossbeam being provided with a first slide groove extending along the length direction of the crossbeam and a plurality of first sliding blocks slidably connected to the first slide groove, the number of the upper line scanning cameras being multiple, and each upper line scanning camera being arranged on a first sliding block.

[0007] Preferably, the lower sliding bracket is provided with a second sliding groove extending along the length direction of the lower sliding bracket and a plurality of second sliding blocks slidably connected to the second sliding groove; the number of the lower line scanning cameras is multiple, and each lower line scanning camera is arranged on a second sliding block; the two ends of the lower sliding bracket are respectively hinged to the lower part of the frame.

[0008] Preferably, each end of the lower sliding bracket is provided with a first circular hole, a first oblong hole, a first hinge and a first locking member, the end of the lower sliding bracket is hinged to the lower part of the frame through the first hinge and the first circular hole, and the end of the lower sliding bracket is connected to the lower part of the frame through the first locking member and the first oblong hole.

[0009] Preferably, the two ends of the light source bracket are respectively hinged to the lower part of the frame, and each end of the light source bracket is provided with a second circular hole, a second long arc hole, a second hinge and a second locking member. The end of the light source bracket is hinged to the lower part of the frame through the second hinge and the second circular hole, and the end of the light source bracket is connected to the lower part of the frame through the second locking member and the second long arc hole.

[0010] Preferably, the conveying unit includes a servo motor and a plurality of conveyor belt assemblies arranged in sequence along the conveying direction of the light guide plate, the output end of the servo motor is fixedly connected to the input end of a conveyor belt assembly, and the plurality of conveyor belt assemblies are connected through a transmission belt and a transmission pulley.

[0011] Preferably, the light guide plate defect visual inspection device also includes a feed sensor and a control unit, the feed sensor is arranged at the end position of the top of the frame, the control unit is electrically connected to the feed sensor, the conveying unit and the image acquisition unit respectively, and the control unit is used to control the conveying action of the conveying unit and the image acquisition action of the image acquisition unit according to the signal of the feed sensor.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] The present invention provides a light guide plate defect visual inspection device, wherein an upper line-scanning camera is perpendicular to the front side of the light guide plate, while a lower line-scanning camera and a line-scanning light source form an angle with the back side of the light guide plate. This configuration realizes simultaneous inspection of the front and back sides and can capture surface reflected and scattered light, thereby facilitating comprehensive inspection of surface defects and internal defects of the light guide plate and capturing different types of defects, especially internal defects of the light guide plate that are more easily observed at an inclined angle. There is no need to perform film tearing operations for inspection of the light guide plate, thereby eliminating the need for cleaning and laminating operations for the light guide plate after inspection, thereby improving work efficiency. The adjustable light source and camera angle can adapt to different types of light guide plates, thereby enabling the light guide plate defect visual inspection device to maintain high efficiency and accuracy when processing light guide plates of different materials and thicknesses, thereby improving inspection adaptability and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0015] Figure 1 It is a schematic diagram of the main structure of a light guide plate defect visual detection device of the present invention;

[0016] Figure 2 It is a top view of a three-dimensional structure schematic diagram of a light guide plate defect visual detection device of the present invention;

[0017] Figure 3 It is a schematic diagram of a three-dimensional structure of a light guide plate defect visual detection device according to the present invention when viewed from above;

[0018] Figure 4It is a partial three-dimensional structural schematic diagram of the upper sliding bracket and the upper line scanning camera in the present invention;

[0019] Figure 5 It is a partial three-dimensional structural schematic diagram of the lower sliding bracket and the lower line scanning camera in the present invention;

[0020] Figure 6 It is a partial three-dimensional structural schematic diagram of the lower sliding bracket in the present invention;

[0021] Figure 7 It is a partial three-dimensional structural schematic diagram of the light source bracket in the present invention;

[0022] Figure 8 It is a side view structural schematic diagram of a light guide plate defect visual detection device of the present invention;

[0023] Fig. 9 is a schematic diagram of electrical connections of the control unit in the present invention;

[0024] In the figure: 1, frame; 2, conveying unit; 3, image acquisition unit; 4, feed sensor; 5, control unit; 201, servo motor; 202, conveyor belt assembly; 203, transmission belt; 204, transmission pulley; 301, upper line scanning camera; 302, lower line scanning camera; 303, line scanning light source; 304, upper sliding bracket; 305, lower sliding bracket; 306, light source bracket; 3041, first slide groove; 3042, first slider; 3051, second slide groove; 3052, second slider; 3053, first circular hole; 3054, first long circular arc hole; 3055, first hinge; 3056, first locking member; 3061, second circular hole; 3062, second long circular arc hole; 3063, second hinge; 3064, second locking member. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any form of modification and / or change made to the present invention will fall within the protection scope of the present invention.

[0026] In the present invention, unless otherwise specified, all parts and percentages are weight units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, unless otherwise specified, are conventional methods in the art. The components or equipment in the following embodiments, unless otherwise specified, are universal standard parts or components known to those skilled in the art, and their structures and principles are known to those skilled in the art through technical manuals or conventional experimental methods.

[0027] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, one or more embodiments may also be implemented by those skilled in the art without these specific details.

[0028] like Figure 1-3 As shown, an embodiment of the present invention discloses a light guide plate defect visual inspection device, comprising a frame 1, a conveying unit 2 and an image acquisition unit 3. The conveying unit 2 is installed on the top of the frame 1, and is used to convey the light guide plate to move relative to the frame 1 and pass through the image acquisition position. The image acquisition unit 3 comprises an upper line scan camera 301, a lower line scan camera 302, a line scan light source 303, an upper sliding bracket 304, a lower sliding bracket 305 and a light source bracket 306.

[0029] The bottom of the upper sliding bracket 304 is fixedly connected to the top of the frame 1, and the upper line scanning camera 301 is slidably set on the top of the upper sliding bracket 304. The upper line scanning camera 301 is used to collect the front image of the light guide plate from above the image collection position, and the scanning direction of the upper line scanning camera 301 is perpendicular to the front of the light guide plate.

[0030] The lower sliding bracket 305 is arranged at the lower part of the frame 1, and the inclination angle of the lower sliding bracket 305 relative to the frame 1 is adjustable. The lower line scanning camera 302 is slidably arranged on the top of the lower sliding bracket 305. The lower line scanning camera 302 is used to collect the back image of the light guide plate from below the image collection position. The scanning direction of the lower line scanning camera 302 forms an angle with the back of the light guide plate.

[0031] The light source bracket 306 is arranged at the lower part of the frame 1, and the line scanning light source 303 is arranged on the light source bracket 306, and the inclination angle of the line scanning light source 303 relative to the light source bracket 306 is adjustable. The line scanning light source 303 is used to illuminate the back side of the light guide plate from below the image acquisition position, and the irradiation direction of the line scanning light source 303 forms an angle with the back side of the light guide plate.

[0032] Specifically, Figure 4 As shown, the upper sliding bracket 304 is a gantry bracket with a crossbeam, the crossbeam is provided with a first slide groove 3041 extending along the length direction of the crossbeam and four first sliders 3042 slidably connected to the first slide groove 3041, the number of upper line scanning cameras 301 is also four, and each upper line scanning camera 301 is arranged on a first slider 3042. Of course, the number of the first sliders 3042 and the upper line scanning cameras 301 can be synchronously adjusted according to the actual application needs. The structure of the upper sliding bracket 304 enables the position of the upper line scanning camera 301 to be adjusted according to light guide plates of different sizes to ensure that it covers the detection area.

[0033] Specifically, Figure 5As shown, the lower sliding bracket 305 is provided with a second slide groove 3051 extending along the length direction of the lower sliding bracket 305 and a plurality of second sliders 3052 slidably connected to the second slide groove 3051. The number of the lower line scanning cameras 302 is multiple, and each lower line scanning camera 302 is arranged on a second slider 3052; the two ends of the lower sliding bracket 305 are respectively hinged to the lower part of the frame 1.

[0034] Specifically, Figure 6 As shown, each end of the lower sliding bracket 305 is provided with a first circular hole 3053, a first long circular arc hole 3054, a first hinge 3055 and a first locking member 3056. The end of the lower sliding bracket 305 is hinged to the lower part of the frame 1 through the first hinge 3055 and the first circular hole 3053, and the end of the lower sliding bracket 305 is connected to the lower part of the frame 1 through the first locking member 3056 and the first long circular arc hole 3054. The hinge and locking structure are used to achieve precise adjustment and fixation of the tilt angle of the lower sliding bracket 305, and the optimal detection angle is adjusted according to the characteristics of different light guide plates and maintained stable.

[0035] Specifically, the two ends of the light source bracket 306 are respectively hinged to the lower part of the frame 1, such as Figure 7 As shown, each end of the light source bracket 306 is provided with a second circular hole 3061, a second long circular arc hole 3062, a second hinge 3063 and a second locking member 3064. The end of the light source bracket 306 is hinged to the lower part of the frame 1 through the second hinge 3063 and the second circular hole 3061, and the end of the light source bracket 306 is connected to the lower part of the frame 1 through the second locking member 3064 and the second long circular arc hole 3062. The hinge and locking structure realizes the precise adjustment and fixation of the tilt angle of the light source bracket 306, facilitates the adjustment of the light source angle, and thus enhances the visibility of specific types of defects.

[0036] Specifically, Figure 8 As shown, the conveying unit 2 includes a servo motor 201 and a plurality of conveyor belt assemblies 202 arranged in sequence along the conveying direction of the light guide plate. The output end of the servo motor 201 is fixedly connected to the input end of a conveyor belt assembly 202, and the plurality of conveyor belt assemblies 202 are connected through a transmission belt 203 and a transmission pulley 204.

[0037] Specifically, the light guide plate defect visual detection device also includes a feed sensor and a control unit 5. The feed sensor is arranged at the end position of the top of the frame 1. Fig. 9 As shown, the control unit 5 is electrically connected to the feed sensor, the conveying unit 2 and the image acquisition unit 3 respectively, and the control unit 5 is used to control the conveying action of the conveying unit 2 and the image acquisition action of the image acquisition unit 3 according to the signal of the feed sensor.

[0038] The upper line scan camera 301 of the light guide plate defect visual inspection device is perpendicular to the front of the light guide plate, while the lower line scan camera 302 and the line scan light source 303 are at an angle to the back of the light guide plate. This configuration realizes simultaneous inspection of the front and back sides, and can capture surface reflection and scattered light, which helps to comprehensively detect surface defects and internal defects of the light guide plate, and capture different types of defects, especially internal defects of the light guide plate that are more easily observed at an inclined angle. There is no need to tear off the film when inspecting the light guide plate, which eliminates the need for cleaning and laminating the light guide plate after inspection, thereby improving work efficiency. The adjustable light source and camera angle can adapt to different types of light guide plates, so that the light guide plate defect visual inspection device can maintain high efficiency and accuracy when processing light guide plates of different materials and thicknesses, thereby improving detection adaptability and reliability.

[0039] The working process of the light guide plate defect visual inspection device is as follows:

[0040] The operator adjusts the position of the upper line scan camera 301 on the upper sliding bracket 304, and the tilt angles of the lower line scan camera 302 and the line scan light source 303 according to the characteristics of the light guide plate to be inspected;

[0041] Feeding starts. When the light guide plate reaches the feeding position, the feeding sensor detects its presence and sends a signal to the control unit 5;

[0042] After receiving the feeding signal, the control unit 5 immediately starts the servo motor 201, drives the conveyor belt assembly 202 to start running, and conveys the light guide plate to the image acquisition position;

[0043] When the light guide plate approaches the image acquisition position, the control unit 5 activates the upper and lower line scan cameras 302 and the line scan light source 303 to put them into a ready state;

[0044] When the light guide plate enters the image acquisition position, the upper line scan camera 301 scans perpendicularly to the front of the light guide plate, while the lower line scan camera 302 and the line scan light source 303 scan and illuminate the back of the light guide plate at a preset angle, capturing surface and internal defects of the light guide plate at the same time;

[0045] As the light guide plate continues to move, multiple upper line scanning cameras 301 and lower line scanning cameras 302 work together to ensure that the entire surface of the light guide plate is completely scanned without leaving any blind spots;

[0046] The collected image data is transmitted to the control unit 5 in real time for processing and analysis. The control unit 5 processes the image using a preset algorithm to identify various defects such as possible surface scratches, internal bubbles, impurities, etc.

[0047] Specifically, the optimal angle range a of the lower line scan camera 302 relative to the back of the light guide plate, and the optimal angle range b of the line scan light source 303 relative to the back of the light guide plate, are both limited to between 30° and 60°. Within this range, it is possible to effectively capture defects inside the light guide plate, avoid excessively vertical illumination that would cause certain defects to be obscured or difficult to identify, and achieve a good balance between the surface reflection and internal scattering of the light guide plate, which helps to simultaneously detect surface defects such as scratches and internal defects such as bubbles. In addition, angles above 30° can effectively reduce the specular reflection on the surface of the light guide plate, thereby reducing the interference of strong reflections on camera imaging, while angles below 60° ensure that light can fully penetrate the light guide plate, enhancing the ability to detect deep defects in the light guide plate, especially thicker ones.

[0048] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A light guide plate defect visual inspection device, characterized in that: The light guide plate defect visual inspection device comprises a frame (1), a conveying unit (2) and an image acquisition unit (3); the conveying unit (2) is installed on the top of the frame (1); the conveying unit (2) is used to convey the light guide plate to move relative to the frame (1) and pass through an image acquisition position; the image acquisition unit (3) comprises an upper line scanning camera (301), a lower line scanning camera (302), a line scanning light source (303), an upper sliding bracket (304), a lower sliding bracket (305) and a light source bracket (306); the bottom of the upper sliding bracket (304) is fixedly connected to the top of the frame (1); the upper line scanning camera (301) is slidably arranged on the top of the upper sliding bracket (304); the upper line scanning camera (301) is used to acquire a front image of the light guide plate from above the image acquisition position; the scanning direction of the upper line scanning camera (301) is perpendicular to the light guide plate. the front side of the light guide plate; the lower sliding bracket (305) is arranged at the lower part of the frame (1), and the inclination angle of the lower sliding bracket (305) relative to the frame (1) is adjustable; the lower line scanning camera (302) is slidably arranged on the top of the lower sliding bracket (305); the lower line scanning camera (302) is used to collect the back side image of the light guide plate from below the image collection position; the scanning direction of the lower line scanning camera (302) forms an angle with the back side of the light guide plate; the light source bracket (306) is arranged at the lower part of the frame (1); the line scanning light source (303) is arranged on the light source bracket (306), and the inclination angle of the line scanning light source (303) relative to the light source bracket (306) is adjustable; the line scanning light source (303) is used to irradiate the back side of the light guide plate from below the image collection position; the irradiation direction of the line scanning light source (303) forms an angle with the back side of the light guide plate.

2. The light guide plate defect visual inspection device according to claim 1, characterized in that: The upper sliding bracket (304) is a gantry-type bracket with a crossbeam, the crossbeam is provided with a first slide groove (3041) extending along the length direction of the crossbeam and a plurality of first sliders (3042) slidably connected to the first slide groove (3041), the number of the upper line scanning cameras (301) is multiple, and each upper line scanning camera (301) is arranged on a first slider (3042).

3. The light guide plate defect visual inspection device according to claim 1, characterized in that: The lower sliding bracket (305) is provided with a second sliding groove (3051) extending along the length direction of the lower sliding bracket (305) and a plurality of second sliding blocks (3052) slidably connected to the second sliding groove (3051); the number of the lower line scanning cameras (302) is multiple, and each lower line scanning camera (302) is arranged on a second sliding block (3052); the two ends of the lower sliding bracket (305) are respectively hinged to the lower part of the frame (1).

4. The light guide plate defect visual inspection device according to claim 3, characterized in that: Each end of the lower sliding bracket (305) is provided with a first circular hole (3053), a first long circular arc hole (3054), a first hinge (3055) and a first locking member (3056); the end of the lower sliding bracket (305) is hinged to the lower part of the frame (1) through the first hinge (3055) and the first circular hole (3053); the end of the lower sliding bracket (305) is connected to the lower part of the frame (1) through the first locking member (3056) and the first long circular arc hole (3054).

5. The light guide plate defect visual inspection device according to claim 1, characterized in that: The two ends of the light source bracket (306) are respectively hinged to the lower part of the frame (1); each end of the light source bracket (306) is provided with a second circular hole (3061), a second long circular arc hole (3062), a second hinge (3063) and a second locking member (3064); the end of the light source bracket (306) is hinged to the lower part of the frame (1) via the second hinge (3063) and the second circular hole (3061); the end of the light source bracket (306) is connected to the lower part of the frame (1) via the second locking member (3064) and the second long circular arc hole (3062).

6. The light guide plate defect visual inspection device according to claim 1, characterized in that: The conveying unit (2) comprises a servo motor (201) and a plurality of conveyor belt assemblies (202) arranged in sequence along the conveying direction of the light guide plate; the output end of the servo motor (201) is fixedly connected to the input end of a conveyor belt assembly (202); and the plurality of conveyor belt assemblies (202) are connected to each other by transmission belts (203) and transmission pulleys (204).

7. The light guide plate defect visual inspection device according to claim 1, characterized in that: The light guide plate defect visual inspection device further comprises a feed sensor and a control unit (5), wherein the feed sensor is arranged at an end position on the top of the frame (1), and the control unit (5) is electrically connected to the feed sensor, the conveying unit (2) and the image acquisition unit (3) respectively, and the control unit (5) is used to control the conveying action of the conveying unit (2) and the image acquisition action of the image acquisition unit (3) according to the signal of the feed sensor.

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