Three-dimensional dynamic optical detection module for gem cutting and polishing process

Abstract

The utility model relates to gem processing detection technical field more specifically, relate to a gem cutting and grinding process three -dimensional dynamic optical detection module, including mounting bracket, the mounting bracket includes upper roof, left side board, lower bottom plate and right side board, the upper roof, left side board, lower bottom plate and right side board combine and form the rectangular structure, wherein the middle part of upper roof is provided with fixed hole, the middle part of lower bottom plate is open, the right side and left side of lower bottom plate are provided with first off -axis parabolic mirror and second off -axis parabolic mirror respectively, the upside of first off -axis parabolic mirror and second off -axis parabolic mirror is provided with semiconductor laser and acquisition camera respectively. First off -axis parabolic mirror focuses laser to gem surface, second off -axis parabolic mirror captures the laser signal of gem surface reflection, and reflects it to acquisition camera, realizes the dynamic focusing of curved surface gem detection without aberration, and this detection mode adopts non -contact detection, avoids the damage of gem surface.

Description

Technical Field

[0001] This utility model relates to the field of gemstone processing and testing technology, and more specifically, to a three-dimensional dynamic optical testing module for the gemstone cutting and polishing process. Background Technology

[0002] In the gemstone cutting and polishing process, surface inspection is a crucial step. It ensures cutting quality, identifies gemstone characteristics and quality, and safeguards the gemstone's value and subsequent processing. During cutting, attention must be paid to the gemstone's symmetry, proportions, and angles. Symmetry requires visual balance, while proportions and angles affect the gemstone's fire and brilliance. Surface inspection determines whether the gemstone's facets are symmetrical and proportionally harmonious, ensuring the gemstone displays its optimal aesthetic effect. Precise cutting maximizes the gemstone's optical effects and increases its value; inappropriate cutting can cause the gemstone to lose its luster and decrease its value. Inspecting the sharpness of the gemstone's facet edges indicates its hardness. Sharp and regular facet edges are also a sign of high-quality cutting. The smoothness of the gemstone's surface is an important indicator of cutting quality. During polishing, it is important to control the pressure and angle of the polishing stone to avoid over-polishing and damage. Real-time surface inspection allows for timely monitoring of the polishing process, ensuring that while enhancing the gemstone's luster and texture, irreversible damage is avoided.

[0003] In the traditional gemstone cutting and polishing process, the gemstone is mainly inspected by manual visual inspection or by contact measuring instruments. However, the above methods have the following technical limitations: (1) Manual inspection is greatly affected by subjective factors and it is difficult to quantify and evaluate the error of the facet angle; (2) The probe of the contact measuring instrument is prone to scratches on the surface of the gemstone, which affects the quality of the finished product; (3) Existing optical inspection equipment mostly uses spherical mirrors, which will produce obvious aberrations when inspecting curved cut surfaces, resulting in measurement errors exceeding 5μm. Utility Model Content

[0004] This invention aims to overcome at least one of the defects (deficiencies) of the prior art and provides a three-dimensional dynamic optical inspection module for the gemstone cutting and polishing process. This module addresses the problems of subjective factors in manual inspection, making it difficult to quantify and evaluate the angle error of the cut surface; the tendency of contact measuring instruments to cause scratches on the gemstone surface; and the significant aberrations that occur when existing optical inspection equipment inspects curved cut surfaces, resulting in measurement errors exceeding 5μm.

[0005] The technical solution adopted by this utility model is a three-dimensional dynamic optical detection module for gemstone cutting and polishing process, including a mounting frame. The mounting frame includes an upper top plate, a left side plate, a lower bottom plate, and a right side plate. The upper top plate, left side plate, lower bottom plate, and right side plate together form a rectangular structure. A fixing hole is provided in the middle of the upper top plate, and an opening is provided in the middle of the lower bottom plate. A first off-axis parabolic reflector and a second off-axis parabolic reflector are respectively provided on the right and left sides of the lower bottom plate. A semiconductor laser and a data acquisition camera are respectively provided directly above the first off-axis parabolic reflector and the second off-axis parabolic reflector.

[0006] In use, the gemstone is placed at the opening of the bottom plate. A semiconductor laser emits the laser beam, and a first off-axis parabolic mirror deflects and focuses the laser onto the gemstone surface. A second off-axis parabolic mirror captures the laser signal reflected from the gemstone surface and reflects it to a camera. The camera then sends the acquired data to an external control and analysis terminal. The laser has an extremely low divergence angle, allowing for long-distance transmission without significant diffusion, ensuring concentrated energy. The focused spot can be as small as a micrometer, enabling precise location of the detection area, making it suitable for small-area analysis of faceted gemstones. Furthermore, the single wavelength of the laser avoids chromatic aberration problems caused by multicolor light. The first and second off-axis parabolic mirrors eliminate the aberrations of traditional spherical mirrors, ensuring distortion-free light path reflection from curved gemstones. They also prevent secondary mirrors or support structures of coaxial parabolic mirrors from obstructing the light path and reducing light transmission efficiency. Combined with the laser, dynamic focusing without aberrations can be achieved for the detection of curved gemstones, making it particularly suitable for the high-precision, non-destructive analysis requirements of gemstones. Meanwhile, the detection module uses non-contact detection, which can effectively avoid damage to the surface of the gemstone.

[0007] Furthermore, the distance between the opening of the lower base plate and the first off-axis parabolic reflector, and the distance between the opening and the second off-axis parabolic reflector, are both L.

[0008] In use, the gemstone is placed at the opening in the lower base plate. The distance between the opening and the first off-axis parabolic mirror is set to be equal to the distance between the second off-axis parabolic mirror and the gemstone. This symmetrical arrangement makes the optical path easy to align, eliminating the need to optimize the angle and distance for each mirror individually. Furthermore, the symmetrical arrangement allows asymmetric aberrations such as coma and astigmatism to cancel each other out, improving focusing and imaging quality. The symmetrical layout also makes the optical path lengths of the laser incident path and the signal return path similar, reducing phase errors caused by optical path differences and helping to reduce phase distortion.

[0009] Furthermore, the distance L between the opening and the first off-axis parabolic mirror is (0.95~1.05)f, where f is the focal length of the first off-axis parabolic mirror.

[0010] The first off-axis parabolic mirror focuses the parallel-incident laser beam to its focal point. Therefore, the gemstone should be placed at the focal point of the first off-axis parabolic mirror to obtain the smallest possible spot size. However, when measuring the surface morphology of the gemstone, the focusing plane needs to be adjusted according to the roughness. The direction of the scattered light from the gemstone is random, and fine-tuning the distance can change the signal collection solid angle, improving signal acquisition efficiency. In addition, the surface of the gemstone may be uneven or have undulations, requiring fine-tuning of the distance to match the actual depth of focus range. Therefore, the distance between the opening and the first off-axis parabolic mirror is set to (0.95~1.05)f, and fine-tuning is used to compensate for the errors of the actual system and optimize the detection performance.

[0011] Furthermore, a polarizing filter is disposed between the first off-axis parabolic reflector and the semiconductor laser.

[0012] The beam output by a semiconductor laser may contain non-ideal polarization components, such as some unpolarized stray light, or optical components, such as mirrors and lenses, which may introduce random polarization noise. Polarization filters only allow specific polarization directions to pass through, blocking stray light from other directions, optimizing the polarization characteristics of the laser, reducing the interference of ambient light or laser noise on the detection, thereby improving the signal-to-noise ratio of the detection system, suppressing interference signals, and enhancing the ability to identify specific features on the surface of gemstones.

[0013] Furthermore, the polarizing filter is detachably disposed between the first off-axis parabolic mirror and the semiconductor laser.

[0014] Different types of gemstones may require different polarization filters for testing. Polarization filters may experience performance degradation due to prolonged use or contamination, necessitating replacement of aged filters. Furthermore, filters may need to be temporarily removed when verifying the original polarization state of a laser. Designing the polarization filter as detachable facilitates removal and replacement, allowing it to adapt to different testing needs, optimize optical performance, and enhance the flexibility and versatility of the testing module.

[0015] Furthermore, a bracket is provided in the middle of the right side plate of the mounting bracket, and a mounting hole is provided on the bracket. A flange is provided in the mounting hole, and the polarizing filter is placed on the flange.

[0016] The bracket is fixed on the mounting frame, and the bracket is provided with mounting holes. A flange is provided in the mounting holes, and the polarizing filter is placed on the flange. When it is necessary to remove or replace the polarizing filter, it can be removed from the mounting holes to achieve the detachable polarizing filter. The operation is simple and convenient.

[0017] Furthermore, the polarizing filter can be replaced with filters of various different wavelengths.

[0018] Some gemstones exhibit optical anisotropy, showing significant differences in reflection / scattering responses to light with different polarizations. By making polarizing filters detachable and replaceable with filters of different wavelengths, they can adapt to the polarization response characteristics of various gemstones (such as sapphire, ruby, and topaz), enabling characteristic spectral analysis of materials with different refractive indices, such as sapphire and moissanite. Secondly, for different wavelengths of laser light, corresponding polarizing filters must also be matched to avoid efficiency loss.

[0019] Furthermore, the surfaces of the first off-axis parabolic reflector and the second off-axis parabolic reflector are provided with anti-reflection coatings.

[0020] An uncoated reflector substrate reflects approximately 4% of the light at the incident surface. By applying an anti-reflection coating, the single-sided reflectivity can be reduced to <0.5%, allowing more laser energy to reach the target location and improving light transmittance. Secondly, when the second off-axis parabolic surface collects scattered light, the anti-reflection coating reduces the reflection loss of signal light at the incident surface, improving the signal-to-noise ratio of the acquisition camera.

[0021] Furthermore, it also includes a robotic arm, the mounting bracket being fixed to the robotic arm through fixing holes, and the robotic arm being rotatable in the horizontal direction.

[0022] When in use, the mounting base is fixed to the robotic arm through fixing holes. The horizontal rotation of the robotic arm can drive the mounting base to rotate in the horizontal direction, which can ensure that the laser beam can cover all facets or curved areas of the gemstone, avoid detection blind spots, perform multi-directional three-dimensional dynamic detection of the gemstone, and reconstruct the three-dimensional surface of the gemstone, such as polishing depressions or facet angle deviations.

[0023] Furthermore, the robotic arm can rotate in the vertical direction.

[0024] When inspecting large gemstones, a single laser beam cannot cover the entire area. The vertical rotation of the robotic arm causes the mounting base to swing back and forth, allowing the laser beam to cover a wider lateral area, such as the gemstone's girdle or the edge of a specific facet. Furthermore, when an anomaly is detected during horizontal rotation, the back-and-forth swinging allows for precise localization of the area for high-resolution retesting.

[0025] Compared with existing technologies, the advantages of this invention are as follows: By placing a first off-axis parabolic mirror directly below the semiconductor laser, the laser is directionally deflected and focused onto the gemstone surface. A second off-axis parabolic mirror captures the laser signal reflected from the gemstone surface and reflects it to the acquisition camera, achieving non-contact detection of the gemstone surface and avoiding damage to the gemstone surface. Using an off-axis parabolic mirror eliminates the aberrations of traditional spherical mirrors, ensuring distortion-free light path reflection from curved gemstones. It also avoids the secondary mirrors or support structures of coaxial parabolic mirrors blocking part of the light path and reducing light transmission efficiency. Combined with the laser, it enables dynamic focusing without aberrations for curved gemstone detection. Applying anti-reflection coatings to the surfaces of the first and second off-axis parabolic mirrors reduces reflectivity and increases transmittance. The anti-reflection coating on the surface of the second off-axis parabolic mirror also reduces signal light reflection loss at the incident surface, improving the signal-to-noise ratio of the acquisition camera. Placing a polarizing filter between the first off-axis parabolic mirror and the semiconductor laser optimizes the laser's polarization characteristics, reduces interference from ambient light or laser noise, thereby improving the signal-to-noise ratio of the detection system, suppressing interference signals, and enhancing the ability to identify specific features on the gemstone surface. Different types of gemstones may use different polarizing filters, and prolonged use or contamination can lead to performance degradation, requiring replacement. Furthermore, the filter may need to be temporarily removed when verifying the laser's original polarization state. Therefore, the polarizing filter is designed to be detachable for easy removal and replacement. The polarizing filter can be replaced with filters of various wavelengths to adapt to the polarization response characteristics of different gemstones, enabling characteristic spectral analysis of materials with different refractive indices, such as sapphire and moissanite. The device also includes a multi-axis robotic arm that can rotate the mounting frame horizontally and vertically, allowing the laser beam to cover all facets or curved areas of the gemstone, avoiding detection blind spots, achieving multi-directional three-dimensional dynamic detection of the gemstone, reconstructing the three-dimensional surface of the gemstone, and accurately locating and re-testing specific areas of the gemstone at high resolution. Attached Figure Description

[0026] Figure 1 This is a structural diagram of the present invention.

[0027] Figure 2 This is a structural diagram of the present invention from another angle.

[0028] Figure 3 This is a schematic diagram of the working state of this utility model.

[0029] Figure 4 This is a structural diagram of the bracket and polarizing filter of this utility model. Detailed Implementation

[0030] This utility model is for illustrative purposes only and should not be construed as limiting the scope of the utility model. To better illustrate the following embodiments, some components in the accompanying drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product; it is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0031] like Figures 1 to 4 As shown, a three-dimensional dynamic optical detection module for gemstone cutting and polishing includes a mounting frame 1. The mounting frame includes an upper top plate 11, a left side plate 12, a lower bottom plate 13, and a right side plate 14. The upper top plate 11, left side plate 12, lower bottom plate 13, and right side plate 14 together form a rectangular structure. A fixing hole 15 is provided in the middle of the upper top plate 11, and an opening is provided in the middle of the lower bottom plate 13. A first base 21 and a second base 31 are respectively provided on the right and left sides of the lower bottom plate 13. A first off-axis parabolic reflector 2 is provided on the first base 21, and a second off-axis parabolic reflector 3 is provided on the second base 31. A semiconductor laser 4 and a camera 5 are respectively provided directly above the first off-axis parabolic reflector 2 and the second off-axis parabolic reflector 3.

[0032] like Figures 1 to 4As shown, specifically, a mounting base 41 is provided at the upper end of the right side plate 14 of the mounting bracket 1. The semiconductor laser 4 is mounted on the mounting base 41, with its output end vertically downward, capable of emitting 650nm laser light. A bracket 61 is provided in the middle section of the right side plate 14. One end of the bracket 61 is connected to the right side plate 14, and the other end has a mounting hole 611. A flange 612 is provided on the lower side of the mounting hole 611. A polarizing filter 6 is placed in the mounting hole 611 and rests on the flange 612. The polarizing filter 6 can be replaced with filters of different wavelengths depending on the type of gemstone being tested, to achieve characteristic spectral analysis compatible with materials with different refractive indices such as sapphire and moissanite. The off-axis angle of both the first off-axis parabolic reflector 2 and the second off-axis parabolic reflector 3 is 90°. The first off-axis parabolic reflector 2 deflects the laser emitted by the semiconductor laser 4 by 90°, causing it to enter the second off-axis parabolic reflector 3 in a horizontal direction. The second off-axis parabolic reflector 3 and the first off-axis parabolic reflector 2 are positioned on the same horizontal line, and the laser signal is reflected to the acquisition camera 5. The surfaces of both the first off-axis parabolic reflector 2 and the second off-axis parabolic reflector 3 are coated with an anti-reflection film, which can reduce light energy loss in the 650nm band and effectively improve the signal-to-noise ratio. The focal length of the first off-axis parabolic mirror 2 and the second off-axis parabolic mirror 3 is f. The distance between the center point of the opening of the lower base plate 13 and the first off-axis parabolic mirror 2 and the second off-axis parabolic mirror 3 is equal to L, and L = (0.95~1.05)f, so that the first off-axis parabolic mirror 2 can focus the laser onto the surface of the gemstone, and the second off-axis parabolic mirror 3 can reflect the laser focused on the surface of the gemstone into collimated light, which is then reflected into the acquisition camera 5.

[0033] The acquisition camera 5 is a CMOS high-speed camera, which can clearly capture the transient process of the interaction between the laser and the gemstone surface. When scanning the gemstone surface at high speed, the CMOS high-speed camera can seamlessly stitch high frame rate images to avoid motion blur. When the mounting bracket 1 rotates around the gemstone, it can continuously capture multi-angle reflection images, thereby constructing a three-dimensional point cloud model of the gemstone. Furthermore, the CMOS high-speed camera also has advantages such as high sensitivity and low noise, which can significantly improve the acquisition capability of weak signals. The acquisition camera 5 is located on the left side of the upper top plate 11, directly above the second off-axis parabolic reflector 3.

[0034] like Figure 3As shown, the detection module also includes a robotic arm 7, which is a conventional multi-axis robotic arm. It includes a horizontally positioned first sleeve 71, a first rotating shaft 72 disposed within the first sleeve 71, a vertically positioned second sleeve 73, and a second rotating shaft 74 disposed within the second sleeve 73. The second sleeve 73 is connected to the first rotating shaft 72. The mounting frame 1 is mounted on the second rotating shaft 74 via a fixing hole 15 on the upper top plate 11. The second rotating shaft 74 can drive the mounting frame 1 to rotate horizontally relative to the second sleeve 73; the first rotating shaft 72 can drive the second sleeve 73, the second rotating shaft 74, and the mounting frame 1 to rotate vertically relative to the first sleeve 71, thereby causing the mounting frame 1 to swing back and forth.

[0035] like Figure 3 As shown, during use, the gemstone is fixed by the clamps of a cutting device such as a cutting machine. The moving detection module positions the gemstone at the opening of the lower base plate 13, with its height aligned with the first off-axis parabolic reflector 2 and the second off-axis parabolic reflector 3. The semiconductor laser emitter 4 is turned on to emit a 650nm laser. After being purified by the polarizing filter 6, the laser is deflected by the first off-axis parabolic reflector 2 and focused onto the surface of the gemstone. The second off-axis parabolic reflector 3 captures the laser signal reflected from the gemstone surface and reflects it to the acquisition camera 5. The acquisition camera 5 sends the acquired data to an external control and analysis terminal. By controlling the robotic arm 7 to rotate the mounting frame 1 horizontally, the laser beam can cover all facets or curved areas of the gemstone, enabling multi-directional three-dimensional dynamic detection and reconstruction of the gemstone's three-dimensional surface. By controlling the robotic arm 7 to swing the mounting frame 1 back and forth, the laser beam can cover a wider lateral area or perform precise positioning and high-resolution retesting of a specific area of ​​the gemstone.

[0036] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the technical solution of this utility model, and are not intended to limit the specific implementation of this utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A three-dimensional dynamic optical inspection module for gemstone cutting and polishing, comprising a mounting frame, the mounting frame including an upper top plate, a left side plate, a lower bottom plate, and a right side plate, the upper top plate, left side plate, lower bottom plate, and right side plate forming a rectangular structure, wherein a fixing hole is provided in the middle of the upper top plate, and an opening is provided in the middle of the lower bottom plate, characterized in that, A first off-axis parabolic reflector and a second off-axis parabolic reflector are respectively installed on the right and left sides of the bottom plate. A semiconductor laser and a data acquisition camera are respectively installed directly above the first off-axis parabolic reflector and the second off-axis parabolic reflector.

2. The three-dimensional dynamic optical detection module for the gemstone cutting and polishing process according to claim 1, characterized in that, The distance between the opening of the lower base plate and the first off-axis parabolic reflector, and the distance between the opening and the second off-axis parabolic reflector, are both L.

3. The three-dimensional dynamic optical detection module for the gemstone cutting and polishing process according to claim 2, characterized in that, The distance L between the opening and the first off-axis parabolic mirror is (0.95~1.05)f, where f is the focal length of the first off-axis parabolic mirror.

4. The three-dimensional dynamic optical inspection module for the gemstone cutting and polishing process according to any one of claims 1-3, characterized in that, A polarizing filter is provided between the first off-axis parabolic reflector and the semiconductor laser.

5. The three-dimensional dynamic optical inspection module for the gemstone cutting and polishing process according to claim 4, characterized in that, The polarizing filter is detachably disposed between the first off-axis parabolic mirror and the semiconductor laser.

6. The three-dimensional dynamic optical inspection module for the gemstone cutting and polishing process according to claim 5, characterized in that, A bracket is provided in the middle of the right side plate of the mounting frame. The bracket has a mounting hole and a flange is provided in the mounting hole. The polarizing filter is placed on the flange.

7. The three-dimensional dynamic optical detection module for the gemstone cutting and polishing process according to claim 6, characterized in that, The polarizing filter can be replaced with filters of various different wavelengths.

8. The three-dimensional dynamic optical inspection module for the gemstone cutting and polishing process according to any one of claims 1-3, characterized in that, The surfaces of the first off-axis parabolic reflector and the second off-axis parabolic reflector are provided with anti-reflection coatings.

9. The three-dimensional dynamic optical inspection module for the gemstone cutting and polishing process according to any one of claims 1-3, characterized in that, It also includes a robotic arm, the mounting bracket of which is fixed to the robotic arm through fixing holes, and the robotic arm is rotatable in the horizontal direction.

10. The three-dimensional dynamic optical detection module for the gemstone cutting and polishing process according to claim 9, characterized in that, The robotic arm can rotate in the vertical direction.

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