A non-contact laser scanning measurement system for flatness and thickness of glass

Abstract

This invention discloses a non-contact laser scanning measurement system for glass flatness and thickness, relating to the field of glass inspection technology. The invention includes a support roller conveying mechanism, a light-emitting component, a primary reflector, a secondary reflector, a light-shielding steel strip, and a light image receiving module. A servo motor drives the primary reflector and the light-shielding steel strip to achieve synchronous scanning, allowing the laser beam to move across the entire glass surface and have its image signal acquired by the receiving module. When detecting flatness, the beam is perpendicularly irradiated onto the glass; when detecting thickness, the tilt angle of the primary reflector is adjusted so that the beam deflection caused by glass refraction is used to calculate the thickness. The system uses a light-shielding housing and a light-shielding steel strip to isolate external light, improving the signal-to-noise ratio and detection accuracy, enabling high-precision identification of glass flatness defects and measurement of thickness.

Description

Technical Field

[0001] This invention relates to the field of glass inspection technology, specifically a non-contact laser scanning measurement system for glass flatness and thickness. Background Technology

[0002] Currently, the glass processing industry generally relies on contact measuring instruments, such as contact thickness gauges and mechanical probe-based flatness measurement structures, to inspect glass flatness and thickness. These methods can cause minor scratches on the glass surface. In high-end glass manufacturing, products are large and have fragile, delicate surfaces, requiring extremely high protection capabilities from the inspection system. Existing optical non-contact measurement systems are typically complex in structure, sensitive to ambient light, and easily affected by stray light, leading to decreased measurement accuracy. Furthermore, existing systems require separate equipment to measure flatness and thickness, making it impossible to achieve a single system capable of handling both inspection requirements. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention provides the following technical solution: a non-contact laser scanning measurement system for glass flatness and thickness, comprising two symmetrically and parallelly arranged support roller supports, with multiple support rollers rotatably mounted between the two support roller supports on the same horizontal plane, the support rollers being used to support and transport the glass to be measured; further comprising a secondary reflector slidably mounted on a central slide rail plate, wherein the secondary reflector is positioned below the glass to be measured, and a primary reflector is slidably mounted on a horizontal crossbeam slide rail directly above the secondary reflector, wherein the primary reflector and the secondary reflector move synchronously and aligned; further comprising a light-emitting component for generating a laser source, wherein the light beam emitted by the light-emitting component is reflected by the primary reflector and passes through the glass to be measured to the secondary reflector, and the secondary reflector reflects the light beam to a position that can be received by a light image receiving module.

[0004] Preferably, the two ends of the horizontal beam slide are fixedly installed on the two support roller supports by two horizontal beam slide brackets, and the horizontal beam slide is set parallel to the central slide rail plate; wherein the central slide rail plate is fixed on the bottom plate inside the light-shielding housing, and the light image receiving module is also fixedly installed on the bottom plate inside the light-shielding housing.

[0005] Preferably, the secondary reflector is tilted and fixedly mounted on the secondary reflector support slider, and the secondary reflector support slider is slidably mounted on the central slide rail plate along the length direction of the central slide rail plate.

[0006] Preferably, an active light-shielding steel strip winding disc and a driven light-shielding steel strip winding disc are rotatably mounted on opposite sides of the two support roller supports at the same height. A light-shielding steel strip is provided between the active and driven light-shielding steel strip winding discs, with both sides of the light-shielding steel strip wound around the active and driven light-shielding steel strip winding discs respectively. A spring is provided at the rotatable connection between the driven light-shielding steel strip winding disc and the support roller support to provide the power for the driven light-shielding steel strip winding disc to reset its rotation. The active light-shielding steel strip winding disc is fixedly mounted on the output shaft of the second servo drive motor, and the housing of the second servo drive motor is fixed on the support roller support.

[0007] Preferably, the light-shielding steel strip has light-passing holes aligned with the secondary reflector and the primary reflector, wherein the light-shielding steel strip and the secondary reflector support slider are fixedly connected by a synchronous motion rod, which is used to drive the secondary reflector and the secondary reflector support slider to slide on the central slide rail plate.

[0008] Preferably, the primary reflector is fixedly mounted on the primary reflector fixing plate. One side of the primary reflector fixing plate is movably connected to the support extension arm, which is fixedly mounted on the primary reflector support slider. The other side of the primary reflector fixing plate is movably connected to the end of the telescopic rod of the adjusting electric cylinder. The end of the telescopic cylinder of the adjusting electric cylinder is movably connected to the primary reflector support slider. The primary reflector support slider is slidably mounted on the horizontal beam slide along the length of the horizontal beam slide. A transmission belt for driving the primary reflector support slider to slide on the horizontal beam slide is also rotatably mounted on the horizontal beam slide. The transmission belt is driven by a first servo drive motor fixedly mounted on the horizontal beam slide bracket.

[0009] Preferably, the light-emitting component includes a light-emitting tube, which is fixedly installed between the inner wall of the light-shielding housing and the horizontal beam slide bracket. The inner wall of the light-emitting tube is fixedly installed with a coaxially arranged light source generating plate, a focusing lens, and a collimating lens, wherein the focusing lens is disposed between the collimating lens and the light source generating plate.

[0010] Preferably, a disassembly plate is fixedly installed on the side of the light-shielding housing, and the light-shielding housing and the disassembly plate form a light-shielding space. Both the light-shielding housing and the disassembly plate are provided with through holes, which are used to accommodate the support roller and the glass to be tested to pass through.

[0011] Compared with the prior art, the present invention has the following advantages: (1) The present invention can freely switch between flatness detection and thickness measurement by adjusting the tilt angle of the first-stage reflector. One set of optical reflection structure can complete the measurement of two key indicators, avoiding the problems of high cost, complex position conversion and limited production cycle caused by the need for multiple equipment combination testing in the prior art, improving the integration of the detection system and the continuous detection capability of the production line, and better meeting the intelligent and automated needs of modern glass production; (2) The present invention uses the first servo motor and the second servo motor to perform closed-loop control of the first-stage reflector support slider and the light-shielding steel strip, so that the first-stage reflector, the light-passing hole and the second-stage reflector strictly maintain synchronous movement, thereby realizing the scanning detection of the entire glass surface without blind spots. It is applicable to glass products of various specifications, and the detection coverage and efficiency are not affected by the increase of glass area, breaking through the problem of limited measurement range of traditional fixed optical systems; (3) The present invention sets up a completely closed light-shielding shell, and forms a light-shielding curtain through a rollable light-shielding steel strip and dense light-shielding strips to isolate external ambient light interference and ensure that the light image receiving module only receives the measurement beam. The optical imaging signal has high contrast and the measurement data is stable and reliable, which significantly improves the accuracy of spot recognition and the sensitivity of flatness micro-defect judgment; (4) This invention utilizes the glass refraction characteristics to determine the surface concavity and thickness of the glass by changing the light intensity and offset position, without any contact element contacting the glass, thus avoiding surface wear caused by traditional touch testing; (5) The light-emitting component of this invention directly contacts the light-shielding housing to generate an effective heat dissipation path, extending the life of the light source. No external complex heat dissipation system is required, reducing the difficulty of equipment maintenance and power consumption. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the light-shielding housing structure of the present invention.

[0013] Figure 2 This is a schematic diagram of the overall structure of the present invention.

[0014] Figure 3 This is a diagram showing the installation position of the horizontal beam slide rail of the present invention.

[0015] Figure 4 This is a schematic diagram of the optical path layout structure of the present invention.

[0016] Figure 5 For the present invention Figure 4 Schematic diagram at point A in the middle.

[0017] Figure 6 This is a schematic diagram of the light-emitting component structure of the present invention.

[0018] In the diagram: 1-Central slide rail plate; 2-Support roller bracket; 3-Active light-shielding steel strip winding disc; 4-Driven light-shielding steel strip winding disc; 5-Light-shielding steel strip; 6-Synchronous motion rod; 7-Secondary reflector support slider; 8-Support roller; 9-Secondary servo drive motor; 10-Light-passing hole; 11-Secondary reflector; 12-Light image receiving module; 13-Horizontal beam slide rail bracket; 14-Horizontal beam slide rail; 15-First servo drive motor; 16-First-stage reflector support slider; 17-Transmission belt; 18-Adjusting electric cylinder; 19-Support extension arm; 20-First-stage reflector fixing plate; 21-First-stage reflector; 22-Light-emitting tube; 23-Light-shielding housing; 24-Disassembly plate; 25-Glass to be tested; 26-Collimating lens; 27-Light source generating plate; 28-Focusing lens. Detailed Implementation

[0019] The following is in conjunction with the appendix Figures 1-6 The technical solution of the present invention will be further illustrated through specific embodiments.

[0020] This invention provides a non-contact laser scanning measurement system for glass flatness and thickness, comprising two symmetrically and parallelly arranged support roller brackets 2, with multiple support rollers 8 rotatably mounted between the two support roller brackets 2 on the same horizontal plane, the support rollers 8 being used to support and transport the glass 25 to be measured; it also includes a secondary reflector 11 slidably mounted on a central slide rail plate 1, wherein the secondary reflector 11 is positioned below the glass 25 to be measured, and a primary reflector 21 slidably mounted on a horizontal crossbeam slide rail 14 is positioned directly above the secondary reflector 11, wherein the primary reflector 21 and the secondary reflector 11 move synchronously aligned; it also includes a light-emitting component for generating a laser source, the light beam emitted by the light-emitting component being reflected by the primary reflector 21 and passing through the glass 25 to be measured onto the secondary reflector 11, the secondary reflector 11 reflecting the light beam to a position that can be received by a light image receiving module 12. The two ends of the horizontal beam slide 14 are respectively fixedly mounted on the two support roller supports 2 by two horizontal beam slide brackets 13, and the horizontal beam slide 14 is arranged parallel to the central slide rail plate 1; wherein the central slide rail plate 1 is fixed on the bottom plate inside the light shield housing 23, and the light image receiving module 12 is also fixedly mounted on the bottom plate inside the light shield housing 23. The secondary reflector 11 is obliquely fixedly mounted on the secondary reflector support slider 7, and the secondary reflector support slider 7 is slidably mounted on the central slide rail plate 1 along the length direction of the central slide rail plate 1.

[0021] Two support roller brackets 2 have an active light-shielding steel strip winding disc 3 and a driven light-shielding steel strip winding disc 4 rotatably mounted on their opposite sides at the same height. A light-shielding steel strip 5 is positioned between the active and driven light-shielding steel strip winding discs 3 and 4, respectively, with its two sides wound around the active and driven light-shielding steel strip winding discs 3 and 4. A spring is provided at the rotatable connection between the driven light-shielding steel strip winding disc 4 and the support roller bracket 2 to provide the power for the driven light-shielding steel strip winding disc 4 to return to its original rotation. The active light-shielding steel strip winding disc 3 is fixedly mounted on the output shaft of the second servo drive motor 9, and the housing of the second servo drive motor 9 is fixedly mounted on the support roller bracket 2. The light-shielding steel strip 5 has light-passing holes 10 aligned with the secondary reflector 11 and the primary reflector 21. The light-shielding steel strip 5 is fixedly connected to the secondary reflector support slider 7 via a synchronous motion rod 6, which drives the secondary reflector 11 and the secondary reflector support slider 7 to slide on the central slide rail plate 1. The primary reflector 21 is fixedly mounted on the primary reflector fixing plate 20. One side of the primary reflector fixing plate 20 is movably connected to the support extension arm 19. The support extension arm 19 is fixedly mounted on the primary reflector support slider 16. The other side of the primary reflector fixing plate 20 is movably connected to the end of the telescopic rod of the adjusting electric cylinder 18. The end of the telescopic cylinder of the adjusting electric cylinder 18 is movably connected to the primary reflector support slider 16. The primary reflector support slider 16 is slidably mounted on the horizontal beam slide 14 along the length direction of the horizontal beam slide 14. A transmission belt 17 for driving the primary reflector support slider 16 to slide on the horizontal beam slide 14 is also rotatably mounted on the horizontal beam slide 14. The transmission belt 17 is driven by the first servo drive motor 15 fixedly mounted on the horizontal beam slide bracket 13.

[0022] The light-emitting component includes a light-emitting tube 22, which is fixedly installed between the inner wall of the light-shielding housing 23 and the horizontal beam slide bracket 13. A light source generating plate 27, a focusing lens 28, and a collimating lens 26 are coaxially mounted on the inner wall of the light-emitting tube 22, with the focusing lens 28 positioned between the collimating lens 26 and the light source generating plate 27. A disassembly plate 24 is fixedly installed on the side of the light-shielding housing 23, forming a light-shielding space. Both the light-shielding housing 23 and the disassembly plate 24 have through holes for accommodating the support roller 8 and the glass to be tested 25.

[0023] The glass to be tested 25 is placed on the support roller 8. Under normal conditions, the support roller 8 is positioned between two conveyor belts. The conveyor belts transport the glass to be tested 25 onto the support roller 8, allowing it to enter the light-shielding housing 23. It should be noted that the support roller 8 has a power drive source to drive all the support rollers 8 to rotate. For ease of demonstration, the width of the light-shielding housing 23 in the attached diagram of the structural specification is not proportional to the actual dimensions. Therefore, in the actual equipment, the width of the light-shielding housing 23 should be greater than the length of the glass to be tested 25 entering the light-shielding housing 23. The environment in which the light-shielding housing 23 is installed should be a dark environment. Multiple densely arranged light-shielding strips are set at the through-hole positions where the glass to be tested 25 enters the light-shielding housing 23 and exits the support roller bracket 2 to form a light-shielding curtain.

[0024] When the light source 27 in the light-emitting tube 22 is directly above the light-transmitting hole 10 of the glass under test 25 (the width of the light-shielding steel strip 5 is greater than the width of the secondary reflector 11, and the surface of the light-shielding steel strip 5 is a light-absorbing matte black coating), the light source emitting plate 27 in the light-emitting tube 22 is powered on. After being powered on, the light emitted by the light source emitting plate 27 is focused by the focusing lens 28 and then focused by the collimating lens 26. Then, the collimating lens 26 collimates multiple inclined light rays and finally emits them out of the light-emitting tube 22. It should be noted that in order to prevent the light beam from damaging the light image receiving module 12, a lower power light source emitting plate 27 is required (such as the brightness of a traditional lighting lamp bead). Since the light source emitting plate 27 is in direct contact with the light-emitting tube 22 and the light-shielding housing 23, the light-shielding housing 23 can be used as a heat dissipation unit during the operation of the light source emitting plate 27 to cool it down. The light beam emitted from the light-emitting tube 22 illuminates the primary reflector 21 and is reflected by the primary reflector 21 onto the glass under test 25. When measuring the surface flatness of the glass under test 25, the light beam needs to be perpendicular to the surface of the glass under test 25. Then, the light beam passes through the light-guiding aperture 10 to the secondary reflector 11 and is reflected by the secondary reflector 11 into the light image receiving module 12. Under normal conditions, because the light beam passes through the glass under test 25, the glass under test absorbs some of the light, resulting in a reduction in the intensity of the light illuminating the light image receiving module 12. When the surface of the glass under test 25 is uneven, such as concave or convex, the uneven area will form a concave or convex lens. This will cause the light beam's exit path through the uneven area of ​​the glass under test 25 to change, resulting in a light spot in the light image received by the light image receiving module 12 that is different from other locations. The approximate size of the uneven area can be determined by the shape, size, and brightness of the light spot. This is because the glass itself causes light to refract. The larger the unevenness, the greater the degree of light refraction, and the lower the light intensity received by the light image receiving module 12. Conversely, if the light is refracted in the direction that the light image receiving module 12 can receive, the light intensity received by the light image receiving module 12 will increase.

[0025] By controlling the first servo drive motor 15 and the second servo drive motor 9, the output shafts of the first servo drive motor 15 and the second servo drive motor 9 respectively drive the transmission belt 17 and the active light-shielding steel strip winding disc 3 to rotate. The rotation of the transmission belt 17 drives the first-stage reflector support slider 16 to slide on the horizontal crossbeam slide rail 14, thereby driving the first-stage reflector 21 to move. The rotation of the active light-shielding steel strip winding disc 3 is used to wind the light-shielding steel strip 5 onto the active light-shielding steel strip winding disc 3. During this process, the light-shielding steel strip 5 wound on the driven light-shielding steel strip winding disc 4 is pulled out. Since a spring is provided at the rotational connection between the driven light-shielding steel strip winding disc 4 and the support roller bracket 2, the light-shielding steel strip 5 is always kept taut. It is necessary to ensure that the first servo drive motor 15 and the second servo drive motor 9 drive the first-stage reflector 21 and the light-tracing aperture 10 to move synchronously. Therefore, a grating ruler is needed at the horizontal crossbeam slide rail 14 to detect the movement distance of the first-stage reflector support slider 16, and a grating ruler is needed between the two support roller brackets 2 to detect the movement distance of the light-tracing aperture 10. Two grating rulers provide drive data to the first servo drive motor 15 and the second servo drive motor 9 respectively to form a closed-loop control. When the light-shielding steel belt 5 moves, it drives the secondary reflector 11 on the secondary reflector support slider 7 through the synchronous motion rod 6. This ensures that the first reflector 21, the light-guiding aperture 10 and the secondary reflector 11 move at the same speed and with the same displacement distance, so that the light emitted by the light-emitting tube 22 can always be received by the light image receiving module 12. Combined with the linear movement of the glass under test 25 on the support roller 8, it is possible to achieve all-round detection of the glass under test 25 without blind spots. When it is necessary to measure the thickness of the glass 25 to be tested, the control cylinder 18 is used to adjust the tilt angle of the primary reflector 21, so that the light beam reflected by the primary reflector 21 onto the glass 25 to be tested is tilted to the surface of the glass 25. In this way, the light beam can penetrate the glass 25 at an angle. At this time, the light beam passing through the glass 25 will be refracted by the glass 25 to the parallel position of the light beam exiting the glass 25. This offset depends on the thickness of the glass 25 to the test. Finally, it will still be reflected by the secondary reflector 11 to the light image receiving module 12. Therefore, the position of the light beam received by the light image receiving module 12 when there is no glass 25 to be tested is compared with the position of the light beam received by the light image receiving module 12 when there is glass 25 to be tested. The offset is determined by the pixel size and number inside the light image receiving module 12, thereby determining the thickness of the glass 25 to be tested. It should be noted that the flatness is measured at the same time as the thickness of the glass 25 to be tested. Conversely, if the thickness of the glass 25 to be tested cannot be measured in the step of measuring the flatness, this needs to be measured according to the process requirements. If only the flatness of the glass 25 to be tested needs to be measured, this method can be selected to reduce the amount of data processing.

Claims

1. A non-contact laser scanning measurement system for glass flatness and thickness, characterized in that: It includes two symmetrical and parallel support roller brackets (2), and multiple support rollers (8) on the same horizontal plane are rotatably installed between the two support roller brackets (2). The support rollers (8) are used to support and transport the glass (25) to be tested. It also includes a secondary reflector (11) that is slidably mounted on the central slide rail plate (1), wherein the secondary reflector (11) is located below the glass (25) to be tested, wherein a primary reflector (21) that is slidably mounted on the horizontal beam slide rail (14) is located directly above the secondary reflector (11), wherein the primary reflector (21) and the secondary reflector (11) move synchronously aligned. It also includes a light-emitting component for generating a laser source. The light beam emitted by the light-emitting component is reflected by a primary reflector (21) and passes through the glass under test (25) to a secondary reflector (11). The secondary reflector (11) reflects the light beam to a position that can be received by the light image receiving module (12).

2. The non-contact laser scanning measurement system for glass flatness and thickness according to claim 1, characterized in that: The two ends of the horizontal beam slide (14) are fixedly installed on the two support roller brackets (2) by two horizontal beam slide brackets (13), and the horizontal beam slide (14) is set parallel to the central slide plate (1); the central slide plate (1) is fixed on the bottom plate inside the light shield housing (23), and the light image receiving module (12) is also fixedly installed on the bottom plate inside the light shield housing (23).

3. The non-contact laser scanning measurement system for glass flatness and thickness according to claim 2, characterized in that: The secondary reflector (11) is fixedly mounted on the secondary reflector support slider (7) at an angle. The secondary reflector support slider (7) is slidably mounted on the central slide rail (1) along the length direction of the central slide rail (1).

4. The non-contact laser scanning measurement system for glass flatness and thickness according to claim 3, characterized in that: Two support roller brackets (2) are rotatably mounted on opposite sides at the same height position with an active light-shielding steel strip winding disc (3) and a driven light-shielding steel strip winding disc (4). A light-shielding steel strip (5) is provided between the active light-shielding steel strip winding disc (3) and the driven light-shielding steel strip winding disc (4). The two sides of the light-shielding steel strip (5) are wound on the active light-shielding steel strip winding disc (3) and the driven light-shielding steel strip winding disc (4) respectively. A spring is provided at the rotatable connection between the driven light-shielding steel strip winding disc (4) and the support roller bracket (2) to provide the power for the driven light-shielding steel strip winding disc (4) to reset and rotate. The active light-shielding steel strip winding disc (3) is fixedly mounted on the output shaft of the second servo drive motor (9). The housing of the second servo drive motor (9) is fixed on the support roller bracket (2).

5. The non-contact laser scanning measurement system for glass flatness and thickness according to claim 4, characterized in that: The light-shielding steel strip (5) has light-passing holes (10) aligned with the secondary reflector (11) and the primary reflector (21). The light-shielding steel strip (5) and the secondary reflector support slider (7) are fixedly connected by a synchronous motion rod (6) to drive the secondary reflector (11) and the secondary reflector support slider (7) to slide on the central slide rail plate (1).

6. The non-contact laser scanning measurement system for glass flatness and thickness according to claim 5, characterized in that: The primary reflector (21) is fixedly mounted on the primary reflector fixing plate (20). One side of the primary reflector fixing plate (20) is movably connected to the support extension arm (19). The support extension arm (19) is fixedly mounted on the primary reflector support slider (16). The other side of the primary reflector fixing plate (20) is movably connected to the end of the telescopic rod of the adjusting electric cylinder (18). The end of the telescopic cylinder of the adjusting electric cylinder (18) is movably connected to the primary reflector support slider (16). The primary reflector support slider (16) is slidably mounted on the horizontal beam slide (14) along the length direction of the horizontal beam slide (14). A transmission belt (17) for driving the primary reflector support slider (16) to slide on the horizontal beam slide (14) is also rotatably mounted on the horizontal beam slide (14). The transmission belt (17) is driven by the first servo drive motor (15) fixedly mounted on the horizontal beam slide bracket (13).

7. The non-contact laser scanning measurement system for glass flatness and thickness according to claim 6, characterized in that: The light-emitting component includes a light-emitting tube (22), which is fixedly installed between the inner wall of the light-shielding housing (23) and the horizontal beam slide bracket (13). The inner wall of the light-emitting tube (22) is fixedly installed with a coaxially arranged light source generating plate (27), a focusing lens (28) and a collimating lens (26), wherein the focusing lens (28) is arranged between the collimating lens (26) and the light source generating plate (27).

8. The non-contact laser scanning measurement system for glass flatness and thickness according to claim 7, characterized in that: A disassembly plate (24) is fixedly installed on the side of the light-shielding housing (23). The light-shielding housing (23) and the disassembly plate (24) form a light-shielding space. Both the light-shielding housing (23) and the disassembly plate (24) have through holes for accommodating the support roller (8) and the glass to be tested (25) to pass through.

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