Lens upper and lower mold dark mark overlapping method

Abstract

The invention discloses a lens upper and lower mold dark mark coincidence method. The method comprises the following steps of dark mark prefabrication, benchmark calibration, preliminary positioning, precise coincidence and coincidence verification. Through the main and auxiliary dark mark combined design, the visual positioning system and servo motor fine adjustment, the dark mark coincidence precision is smaller than or equal to 0.001 mm and is far higher than the positioning precision in the prior art, and the high-precision lens production requirement is met. The whole coincidence process is high in automation degree, manual intervention is not needed, the preliminary positioning step and the accurate coincidence step are rapidly joined, the coincidence time of a single set of molds is smaller than or equal to 30 s, and the production efficiency is greatly improved. And pressure distribution detection is adopted as a coincidence verification means, so that the fitting state of the mold can be comprehensively reflected, misjudgment possibly caused by single dark mark positioning is avoided, and the product percent of pass is improved. The mold positioning device is suitable for mold positioning of various resin lenses and glass lenses and has good adaptability to molds of different sizes and shapes, and the equipment structure does not need to be adjusted in a targeted mode.

Description

Technical Field

[0001] This invention relates to the field of lens forming technology, specifically to a method for aligning the dark marks on the upper and lower molds of a lens. Background Technology

[0002] In the lens manufacturing process, the precise positioning of the upper and lower molds directly affects the optical performance and appearance quality of the lens. This is especially true for lenses with complex curved surfaces or special optical requirements, where extremely high mold positioning accuracy is required. Dark mark positioning, as a concealed positioning method, avoids the influence of the positioning structure on the lens forming surface and is widely used in lens molds.

[0003] However, existing methods for aligning dark markers in lens molds have many shortcomings: on the one hand, the dark marker structure is poorly designed, often using a single marker point or line, resulting in insufficient positioning reference and easy positioning deviation; on the other hand, the positioning process relies on manual operation or simple mechanical positioning, lacking a precise detection and adjustment mechanism, resulting in low dark marker alignment accuracy, typically only ±0.01mm, which is difficult to meet the production requirements of high-precision lenses; in addition, the alignment operation process is complex and time-consuming, affecting production efficiency, and the alignment effect lacks effective verification methods, which easily leads to unqualified products.

[0004] Therefore, developing a method for aligning the upper and lower mold dark marks of a lens with high positioning accuracy, simple operation, and reliable verification has become the key to solving the existing technical problems. Summary of the Invention

[0005] Technical problems to be solved To address the problems existing in the prior art, this invention provides a method for aligning the dark marks on the upper and lower molds of a lens, thus solving the problem mentioned in the background art that the precise positioning of the upper and lower molds is crucial for optical performance in lens production. Dark mark positioning is widely used because it does not affect the forming surface, but existing methods have shortcomings such as simple dark mark design and lack of precise detection mechanisms, resulting in an alignment accuracy of only ±0.01mm, and the lack of verification methods makes it difficult to meet the technical problems of high-precision production requirements.

[0006] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a method for aligning the dark marks on the upper and lower molds of a lens, comprising the following steps: Dark mark prefabrication: Dark mark structures are prefabricated on the lower surface edge of the upper mold and the upper surface edge of the lower mold respectively. The dark mark structure includes a main positioning dark mark and an auxiliary positioning dark mark. The main positioning dark mark is an arc-shaped groove structure, and the auxiliary positioning dark mark is a dot-shaped protrusion structure. The main positioning dark mark and the auxiliary positioning dark mark are distributed in concentric circles. Benchmark calibration: Install the upper mold and lower mold onto the upper mold base and lower mold base of the molding equipment respectively, and adjust the levelness of the upper mold base and lower mold base through the built-in level calibration mechanism of the equipment to ensure that the parallelism error of the reference surface of the upper and lower molds is ≤0.002mm; Preliminary positioning: Start the drive mechanism of the molding equipment to move the upper mold base downward. Use the equipment's vision positioning system to capture the outline of the main positioning mark. Control the upper and lower mold bases to make horizontal fine adjustments so that the central axes of the main positioning marks of the upper and lower molds coincide. The preliminary positioning accuracy is controlled within ±0.005mm. Precise alignment: The visual positioning system is used to identify the auxiliary positioning marks. The positional deviation of the auxiliary positioning marks of the upper and lower molds is calculated by the three-point positioning principle. The mold base is driven to make secondary fine adjustment so that the auxiliary positioning marks of the upper and lower molds correspond and fit one by one. At this time, the main positioning marks are completely aligned, and the alignment accuracy is ≤0.001mm. Overlap verification: The contact pressure distribution after the upper and lower molds are attached is detected by pressure sensor. If the pressure distribution uniformity is ≥98%, the blind mark overlap is deemed qualified; if it is not qualified, the benchmark calibration and preliminary positioning steps are repeated until the overlap is qualified.

[0007] In some embodiments: the radius of the arc-shaped groove of the main positioning mark is 5-10mm, the depth is 0.5-1mm, and the groove wall roughness Ra≤0.8μm; 3-6 auxiliary positioning marks are set and evenly distributed along the circumference of the main positioning mark, and the diameter of the dot-shaped protrusions is 0.3-0.8mm and the height is 0.3-0.6mm.

[0008] In some implementations: the visual positioning system includes a high-definition industrial camera, a laser ranging module, and an image processor. The high-definition industrial camera has ≥12 million pixels and a shooting frame rate ≥30fps. The laser ranging module has a measurement accuracy ≤0.0005mm.

[0009] In some implementations: the horizontal fine-tuning in the benchmark calibration step is driven by a servo motor, the positioning accuracy of the servo motor is ≤0.001mm, and the fine-tuning step size is 0.0002-0.0005mm.

[0010] In some implementations: the pressure sensor used in the overlap verification step is an array-type pressure sensor, with a sensor array density ≥ 10 sensors / cm². 2 The pressure measurement range is 0-50N, and the measurement accuracy is ≤0.01N.

[0011] (III) Beneficial Effects Compared with the prior art, the present invention provides a method for aligning the dark marks on the upper and lower molds of a lens, which has the following beneficial effects: 1. High positioning accuracy: This invention achieves a dark mark overlap accuracy of ≤0.001mm through a combination of main and auxiliary dark marks, a visual positioning system, and servo motor fine adjustment, which is far higher than the positioning accuracy of existing technologies and meets the needs of high-precision lens production.

[0012] 2. Simple and efficient operation: The entire overlapping process is highly automated, requiring no manual intervention. The initial positioning and precise overlapping steps are quickly connected, and the overlapping time for a single mold is ≤30s, which greatly improves production efficiency.

[0013] 3. Reliable verification: Using pressure distribution detection as the overlap verification method can comprehensively reflect the mold fitting status, avoid misjudgment that may occur with single dark mark positioning, and improve the product qualification rate.

[0014] 4. High versatility: It is suitable for mold positioning of various resin lenses and glass lenses, and has good adaptability to molds of different sizes and shapes, without the need for specific adjustments to the equipment structure. Attached Figure Description

[0015] Figure 1 : Overall layout diagram of the automatic mold closing machine. Detailed Implementation

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0017] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0018] In this invention, unless otherwise stated, the directional terms such as "up" and "down" generally refer to the directions shown in the accompanying drawings, or to the vertical, perpendicular, or gravitational direction; similarly, for ease of understanding and description, "left" and "right" generally refer to the left and right shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0019] This embodiment of a method for aligning the upper and lower mold markings of a lens is based on... Figure 1 The automatic mold closing machine includes an AB mold feeding and conveying line 10, a B mold stacking line 20, an A mold handling suction cup 30, an AB mold positioning mechanism 40, an AB mold lifting and rotating mechanism 50, a visual positioning side marking line 60, an adhesive tape applicator 70, and a discharge conveyor line 80.

[0020] A method for aligning the dark marks on the upper and lower molds of a lens includes the following steps: 1. Pre-fabrication of dark markers: A curved groove is pre-fabricated on the lower surface edge of the upper mold as the main positioning dark marker. The groove radius is 8mm, the depth is 0.8mm, and the groove wall roughness Ra=0.6μm. Four dot-shaped protrusions are pre-fabricated on the upper surface edge of the lower mold as auxiliary positioning dark markers. The protrusions are 0.5mm in diameter and 0.4mm in height, and are evenly distributed along the circumference of the main positioning dark marker. The main and auxiliary dark markers are set in concentric circles.

[0021] 2. Reference calibration: Install the upper and lower molds onto the upper mold base and lower mold base of the molding equipment respectively, start the horizontal calibration mechanism, and adjust the level of the mold base so that the parallelism error of the reference surfaces of the upper and lower molds is 0.0015mm.

[0022] As shown in Figure 1, the molding equipment includes a support base, a precision slide rail, and a mold displacement assembly mounted on the slide rail. The upper and lower mold bases are vertically limited by multiple sets of parallel guide pillars to ensure the straightness of the upper and lower mold closing paths. In the benchmark calibration step, the initial flatness of the mold base is compensated by horizontal adjusting bolts or electronic leveling compensation blocks arranged under the base, so that the parallelism error of the upper and lower mold reference surfaces is maintained at an extremely high precision level within 0.002mm, providing a stable geometric reference plane for subsequent nanoscale alignment.

[0023] 3. Preliminary Positioning: The vision positioning system is activated, and a high-definition industrial camera (16 megapixels, 40fps) captures the outline of the main positioning mark. The laser ranging module measures the position data, and after analysis by the image processor, the servo motor (positioning accuracy 0.0008mm) is controlled to perform horizontal fine-tuning with a fine-tuning step of 0.0003mm, so that the central axes of the main positioning marks of the upper and lower molds coincide. The preliminary positioning accuracy is ±0.004mm.

[0024] 4. Precise alignment: The visual positioning system identifies four auxiliary positioning markers, calculates the positional deviation, and the servo motor drives the mold base for secondary fine-tuning, so that the auxiliary positioning markers are aligned one by one. At this time, the main positioning markers are completely aligned, with an alignment accuracy of 0.0009mm.

[0025] As shown in Figure 1, the secondary fine-tuning drive mechanism adopts a splined lead screw shaft structure. The core of this structure lies in: High-precision transmission: The servo motor is directly connected to the splined lead screw via a high-rigidity coupling, eliminating backlash. The splined shaft structure allows for frictionless horizontal displacement compensation of the mold base within a minute range while transmitting torque.

[0026] Micro-step control: Combined with a speed reduction transmission mechanism, the servo motor can achieve a minimum micro-adjustment step size of 0.0002mm.

[0027] Three-point positioning linkage: After the vision positioning system calculates the deviations in the X and Y directions and the rotation angle $\theta$, three (or more) sets of fine-tuning mechanisms distributed around the mold base work in concert. Based on the three-point positioning principle, the mold is driven to complete the final precise fit through the synchronous or differential rotation of the spline screw, so that the auxiliary positioning mark (boss) accurately embeds into or corresponds to the center position of the main positioning mark (groove), thereby achieving an overlap accuracy of ≤0.001mm. 5. Overlap verification: Array-type pressure sensors (12 per cm) 2 The measurement range is 0-30N, and the accuracy is 0.008N. The pressure distribution is detected, and the pressure distribution uniformity is 99.2%, which is considered to be qualified for overlap.

[0028] The above embodiments demonstrate that the lens upper and lower mold dark mark overlap method of the present invention has high positioning accuracy, high operation efficiency, and reliable verification, which can effectively improve lens forming quality and production efficiency, and has important practical application value.

[0029] In summary, the overlapping method in this embodiment also integrates an array-type pressure sensing unit at the end of the fine-tuning drive mechanism. After the servo motor drives the mold to complete physical contact, the pressure sensors collect the force data of each node in real time. If the pressure at a certain point deviates from the average value (uniformity < 98%) due to mechanical wear or foreign objects, the system will automatically feed back to the image processor, triggering the recalibration logic. Through the closed-loop control of the mechanical structure and the sensing system, the influence of positioning deviation on the optical surface performance of the lens is completely eliminated.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for aligning the dark marks on the upper and lower molds of a lens, characterized in that, Includes the following steps: Dark mark prefabrication: Dark mark structures are prefabricated on the lower surface edge of the upper mold and the upper surface edge of the lower mold respectively. The dark mark structure includes a main positioning dark mark and an auxiliary positioning dark mark. The main positioning dark mark is an arc-shaped groove structure, and the auxiliary positioning dark mark is a dot-shaped protrusion structure. The main positioning dark mark and the auxiliary positioning dark mark are distributed in concentric circles. Benchmark calibration: Install the upper mold and lower mold onto the upper mold base and lower mold base of the molding equipment respectively, and adjust the levelness of the upper mold base and lower mold base through the built-in level calibration mechanism of the equipment to ensure that the parallelism error of the reference surface of the upper and lower molds is ≤0.002mm; Preliminary positioning: Start the drive mechanism of the molding equipment to move the upper mold base downward. Use the equipment's vision positioning system to capture the outline of the main positioning mark. Control the upper and lower mold bases to make horizontal fine adjustments so that the central axes of the main positioning marks of the upper and lower molds coincide. The preliminary positioning accuracy is controlled within ±0.005mm. Precise alignment: The visual positioning system is used to identify the auxiliary positioning marks. The positional deviation of the auxiliary positioning marks of the upper and lower molds is calculated by the three-point positioning principle. The mold base is driven to make secondary fine adjustment so that the auxiliary positioning marks of the upper and lower molds correspond and fit together one by one. At this time, the main positioning marks are completely aligned, and the alignment accuracy is ≤0.001mm. Overlap verification: The contact pressure distribution after the upper and lower molds are attached is detected by pressure sensor. If the pressure distribution uniformity is ≥98%, the blind mark overlap is deemed qualified; if it is not qualified, the benchmark calibration and preliminary positioning steps are repeated until the overlap is qualified.

2. The method for aligning the upper and lower mold markings of a lens according to claim 1, characterized in that: The radius of the arc-shaped groove of the main positioning mark is 5-10mm, the depth is 0.5-1mm, and the groove wall roughness Ra≤0.8μm; 3-6 auxiliary positioning marks are set and evenly distributed along the circumference of the main positioning mark, and the diameter of the dot-shaped protrusions is 0.3-0.8mm and the height is 0.3-0.6mm.

3. The method for aligning the upper and lower mold markings of a lens according to claim 1, characterized in that: The visual positioning system includes a high-definition industrial camera, a laser ranging module, and an image processor. The high-definition industrial camera has ≥12 million pixels and a shooting frame rate ≥30fps. The laser ranging module has a measurement accuracy ≤0.0005mm.

4. The method for aligning the upper and lower mold markings of a lens according to claim 1, characterized in that: In the benchmark calibration step, the horizontal fine adjustment is driven by a servo motor. The positioning accuracy of the servo motor is ≤0.001mm, and the fine adjustment step size is 0.0002-0.0005mm.

5. The method for aligning the upper and lower mold markings of a lens according to claim 1, characterized in that: In the overlap verification step, an array-type pressure sensor is used, with a sensor array density of ≥10 sensors / cm². 2 The pressure measurement range is 0-50N, and the measurement accuracy is ≤0.01N.

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