Optical lens UV curing device

Abstract

The invention provides an optical lens UV curing device which comprises an upper cover, a middle holding frame, a UV fixing ring, a UV light head, a to-be-cured lens and a UV curing machine, the middle holding frame is arranged below the upper cover, the UV fixing ring is installed outside the lower side of the middle holding frame, one end of the UV light head is connected with an opening in the side end of the UV fixing ring, and the other end of the UV light head is connected with the UV curing machine through an optical cable. The to-be-cured lens is placed in the middle of the middle holding frame after the upper cover is opened, a plurality of circular grooves which are the same in height and are in a step shape from top to bottom are formed in the inner wall of the middle holding frame from top to bottom, the to-be-cured lens is fixed through the circular grooves, and after the to-be-cured lens is fixed, the to-be-cured lens is placed in the middle of the middle holding frame. And aligning a dispensing hole on the outer diameter of the to-be-cured lens with the center of the notch of the middle holding frame. An existing optical lens UV curing technology has the following core problems that a plane positioning structure is adopted in a traditional device, the position of a lens is prone to deviation when the lens is placed, glue dispensing holes are dislocated, and the glue permeation uniformity is affected.

Description

Technical Field

[0001] The present invention belongs to the field of UV curing, and particularly relates to a UV curing device for optical lenses. Background Art

[0002] Currently, in the assembly of optical lenses and lenses, some structures need to be fixed with UV glue. The UV glue is in a gel state before being irradiated by ultraviolet light and becomes solid after being irradiated by ultraviolet light, playing a role in fixing the lens or lens.

[0003] During the curing process of the UV glue, the volume will change. If the distribution position in the lens is uneven, it will cause the eccentricity of the lens or lens, ultimately affecting the performance of the lens. Therefore, the dispensing positions of most lenses are evenly distributed at three points on the outer diameter of the lens or lens. When curing the UV glue, the curing device needs to be able to cure three points simultaneously, and the distances from the three curing points to the curing light source should be the same. Therefore, in order to meet the mass production conditions, the curing device needs to accurately place the three points of the product to be cured on the curing points within a short time.

[0004] Current UV curing devices for optical lenses still have significant technical bottlenecks in the field of precision optical manufacturing. Traditional UV curing systems mostly use a single wavelength with uneven high-pressure light intensity distribution, resulting in low curing efficiency of lens glue and insufficient edge curing problems, seriously affecting the yield rate of lens assembly. The temperature control accuracy of existing equipment is poor, and the heat generated during the UV irradiation process easily causes thermal deformation of the lens substrate, resulting in a decline in optical performance.

[0005] In terms of optical path design, traditional reflectors use a simple parabolic structure, which cannot achieve dynamic adjustment of the spot shape and is difficult to adapt to the curing requirements of lenses with different diameters and curvatures. Existing systems lack real-time curing monitoring functions. Only by controlling the curing process regularly, they cannot dynamically adjust the UV dose according to the actual curing state of the glue, and the incidence of over-curing or under-curing exceeds 20%. These technical defects make it difficult for existing UV curing devices to meet the requirements of high-precision, high-efficiency, and environmentally friendly manufacturing for high-end optical products such as smartphone lenses and vehicle-mounted cameras.

[0006] The disadvantages of a UV curing fixture described in Patent CN212759509U: The UV light source is located directly above the lens. For the dispensing holes on the lens that need to be cured, the angle is limited and it cannot cure three dispensing holes evenly distributed perpendicular to the outer diameter direction at the same time. Moreover, to adjust the curing position, the lens base and the UV bracket need to be adjusted, and the positioning is relatively complex.

[0007] Disadvantages of the rotating carrier described in Patent CN208125993: The conveyor belt is driven by an electric motor bearing, causing the lens to rotate at a uniform speed of 360° through the UV curing machine. Although the UV glue perpendicular to the outer diameter of the lens can be cured, only the glue that has rotated through the UV curing machine first is cured first, and the glue that has rotated through the UV curing machine later is cured later. It is impossible to ensure that the glue distributed around the outer diameter is cured simultaneously.

[0008] Due to different imaging effects that existing optical lenses need to meet, there are many different outer dimensions. To reduce costs, the curing device needs to be compatible with multiple different outer diameters and dispensing holes of different heights at the same time. Summary of the Invention

[0009] The present invention provides a UV curing device for an optical lens, which can simultaneously cure the UV glue vertically distributed on the outer diameter of the lens and has a simple and accurate positioning of the curing position. The device supports dispensing lenses with various outer diameter specifications, and the curing height can be adjusted arbitrarily.

[0010] The technical solution of the present invention is realized as follows: A UV curing device for an optical lens includes an upper cover, a middle holding frame, a UV fixing ring, a UV optical head, a lens to be cured, and a UV curing machine. A middle holding frame is arranged below the upper cover. A UV fixing ring is installed outside the lower side of the middle holding frame. One end of the UV optical head is connected to the opening on the side of the UV fixing ring, and the other end is connected to the UV curing machine through an optical cable. After the upper cover is opened, the lens to be cured is placed in the middle of the middle holding frame. A number of circular grooves with the same height and in a stepped shape from top to bottom are arranged on the inner wall of the middle holding frame from top to bottom. The position of the lens to be cured is fixed through the circular grooves. After the position of the lens to be cured is fixed, the dispensing hole on the outer diameter of the lens to be cured is aligned with the center of the notch of the middle holding frame.

[0011] The following core problems exist in the existing UV curing technology for optical lenses: The traditional device uses a planar positioning structure, and the lens is prone to position deviation during placement, resulting in misalignment of the dispensing holes and affecting the uniformity of glue penetration; The UV light source is mostly a single-point direct irradiation type, and the light intensity distribution is uneven, causing insufficient curing at the edge of the lens, and the curing time is more than 60 seconds; There is a lack of a precise positioning mechanism, and fixtures need to be frequently replaced for lenses with different diameters, and the changeover time > 5 minutes, seriously affecting production efficiency.

[0012] The following technological innovations are adopted in this solution to address the above difficulties: (1) A stepped circular groove structure is provided on the inner wall of the middle retaining frame. The lens is self-centered through multiple annular steps with the same height, and the positioning accuracy reaches ±0.01 mm, ensuring that the dispensing holes are 100% aligned with the center of the slot opening; (2) The side ends of the UV fixing ring are provided with annularly distributed openings. The UV optical heads are connected by optical cables to form multi-angle irradiation, and the light intensity uniformity is increased to over 90%, and the curing strength at the edge reaches 95% of that at the center; (3) The stepped circular groove is adapted to lenses of different diameters, and the quick change of models is realized by adjusting the levels of the circular groove, and the compatibility is increased by 10 times; (4) The UV optical head and the curing machine are designed separately to avoid the vibration of the equipment being transmitted to the lens. The vibration amplitude during the curing process is <1 μm, ensuring the assembly accuracy of the lens.

[0013] As a preferred embodiment, after the UV fixing ring is installed with the UV optical head, the UV fixing ring is adjusted up and down along the middle retaining frame. By adjusting the UV fixing ring, the UV optical head is aligned with the dispensing position of the lens to be cured.

[0014] As a preferred embodiment, at least two groups of dispensing holes are provided on the outer diameter of the lens to be cured. Each group of dispensing holes has at least 3 holes arranged in an annular array along the outer diameter. When curing, the holes arranged up and down in the two groups of dispensing holes are cured simultaneously.

[0015] As a preferred embodiment, the UV curing machine cures the dispensing of the lens to be cured through ultraviolet light. The ultraviolet light is transmitted from the UV curing machine to the UV optical head through an optical cable. The ultraviolet light focused by the UV optical head irradiates the dispensing holes of the lens to be cured. The UV glue in the dispensing holes is cured after being irradiated by the ultraviolet light to fix the lens or the lens elements.

[0016] As a preferred embodiment, three UV optical heads are provided. The three UV optical heads are arranged in an annular array around the center point of the UV fixing ring on the side end face of the UV fixing ring. When the UV fixing ring moves, the three UV optical heads move and position synchronously, and the three UV optical heads synchronously adjust and control the curing distance from the outside to the inside in the radial direction of the middle retaining frame.

[0017] After adopting the above technical solution, the beneficial effects of the present invention are as follows: The device significantly improves the curing quality and efficiency of optical lenses. The stepped circular groove positioning structure enables a relatively high placement accuracy of the lenses, and the alignment rate of the dispensing holes is significantly improved compared with the traditional method, resulting in an increase in the yield rate compared with the traditional planar positioning; the annularly distributed UV optical heads achieve uniform irradiation from multiple angles, with good light intensity uniformity, small difference in curing strength between the edge and the center, shortened curing time, and improved efficiency; the stepped circular groove design supports rapid changeover of multiple lenses, reducing the changeover time compared with the traditional special fixtures and improving the equipment utilization rate; the separated UV optical path design controls the vibration interference within the set range, avoiding micro-displacement defects in lens assembly; the overall structure adopts a modular design, reducing the maintenance cost by 60%, being applicable to mass production of precision optical products such as smartphone lenses and vehicle-mounted lenses, and reducing the comprehensive production cost.

[0018] With the curing height being adjustable arbitrarily, supporting simultaneous curing of 3 points on the outer diameter, supporting dispensing positions of multiple outer diameter specifications, high compatibility, and simple and accurate positioning of the curing position, only 3 parts (1 upper cover, 2 middle retaining frame, 3 UV fixing frame) of the whole set of UV curing device need to be specially customized, with a simple structure and convenient assembly, resulting in low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 It is a schematic diagram of simultaneously curing 2 groups of dispensing holes in an embodiment of the present invention;

[0022] Figure 3 It is an installation schematic diagram when the outer diameter of the lens to be cured is relatively large in an embodiment of the present invention;

[0023] Figure 4 It is an installation schematic diagram when the outer diameter of the lens to be cured is relatively small in an embodiment of the present invention;

[0024] Figure 5 It is a front view of the cross-section of the retaining frame in the present invention;

[0025] Figure 6 It is a top view of the installation of three UV optical heads in an embodiment of the present invention;

[0026] Figure 7 It is an installation schematic diagram of the UV optical head in an embodiment of the present invention.

[0027] In the figure, 1 - upper cover; 2 - middle holding frame; 3 - UV fixing ring; 4 - UV optical head; 5 - lens to be cured; 6 - UV curing machine. Specific embodiments

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0029] Embodiment:

[0030] As Figure 1 shown, an optical lens UV curing device includes an upper cover 1, a middle holding frame 2, a UV fixing ring 3, a UV optical head 4, a lens to be cured 5, and a UV curing machine 6. A middle holding frame 2 is provided below the upper cover 1. A UV fixing ring 3 is installed outside the lower side of the middle holding frame 2. One end of the UV optical head 4 is connected to the opening on the side end of the UV fixing ring 3, and the other end is connected to the UV curing machine 6 through an optical cable. After the upper cover 1 is opened, the lens to be cured 5 is placed in the middle of the middle holding frame 2. A plurality of circular grooves with the same height and in a stepped shape from top to bottom are arranged on the inner wall of the middle holding frame 2, and the position of the lens to be cured 5 is fixed through the circular grooves. After the position of the lens to be cured 5 is fixed, the dispensing holes on the outer diameter of the lens to be cured 5 are aligned with the center of the notch of the middle holding frame 2.

[0031] In the specific implementation scenario of this application document, the working principle and working process of the optical lens UV curing device are as follows:

[0032] First, the operator places the optical lens to be cured (such as a mobile phone camera lens) in the middle of the middle holding frame 2 of the device. The stepped circular grooves designed on the inner wall of the middle holding frame 2 from top to bottom are machined precisely (tolerance ≤ ±0.01 mm) to match lenses of different diameters (such as diameters of 5 - 20 mm). The alignment accuracy between the dispensing holes on the outer diameter of the lens and the center of the notch is up to ±0.05 mm, ensuring that the UV glue is evenly distributed on the bonding surface between the lens and the lens barrel. When the upper cover 1 is closed, the middle holding frame 2 and the UV fixing ring 3 form a closed optical path space to prevent external stray light from interfering with the curing process.

[0033] The UV lamp head 4 is installed through the standard M6 threaded interface on the side of the UV fixing ring 3. The output end face of its quartz optical fiber is inclined at an angle of 45° to the lens axis, ensuring that the ultraviolet light covers the glue area in a circular radiation manner, and the uniformity of the light intensity distribution is ≥90%. The UV curing machine 6 is driven by high-frequency pulses and outputs UV light with adjustable power through an optical cable. When the curing program is started, the system automatically matches the curing parameters according to the type of glue.

[0034] During the curing process, six temperature sensors built into the middle holding frame 2 monitor the temperature of the glue layer in real time to prevent the lens from deforming due to overheating. After curing is completed, the upper cover 1 is opened, and the operator takes out the lens. The infrared spectrometer detects the curing degree of the glue layer, and unqualified products trigger the secondary curing process.

[0035] This invention consists of an upper cover 1, a middle holding frame 2, a UV fixing ring 3, a UV lamp head 4, a lens to be cured 5, and a UV curing machine 6. As Figure 1 shown, by opening the upper cover 1, the lens to be cured 5 can be placed on the middle holding frame 2. There are many circular grooves with the same height in the middle holding frame 2, which are arranged in a stepped shape from top to bottom. At this time, the lens to be cured 5 can be placed in the circular groove corresponding to its size, as Figure 3 、 4 shown.

[0036] For a lens with a relatively large outer diameter, a circular groove with a relatively large inner diameter is selected, such as Figure 3 . For a lens with a relatively small outer diameter, a circular groove with a relatively small inner diameter is selected, such as Figure 4 on the right. Subsequently, the dispensing holes on the outer diameter of the lens to be cured 5 need to be aligned with the center of the notch on the middle holding frame 2, as Figure 5 shown;

[0037] The UV fixing ring 3 equipped with the UV lamp head 4 can be manually adjusted up and down along the middle holding frame 2. By adjusting the UV fixing ring 3, the UV lamp head 4 can be aligned with the dispensing point, as Figure 2 . For a lens with dispensing holes arranged relatively close to each other vertically, two groups of dispensing holes can be cured simultaneously. For a lens with dispensing holes arranged relatively far apart vertically, the UV fixing ring 3 can be adjusted to separate and cure multiple times. As Figure 2 shown is a lens with two groups of dispensing holes. Since the two groups (each group has an average of 3 distributed along the outer diameter) of dispensing holes are arranged relatively close to each other vertically, they can be cured at one time. As Figure 3 、 4 illustrates two examples. The outer diameter of the lens to be cured 5 in the figure is relatively large, so a circular groove with a relatively large inner diameter on the middle holding frame 2 is selected. At this time, the adjustment height of the UV fixing frame 3 is relatively high. And Figure 4If the outer diameter of the lens 5 to be cured is too small, a circular groove with a relatively small inner diameter on the middle retaining frame is selected. At this time, the height of the UV fixing ring 3 also needs to be reduced accordingly. Since the groove on the middle retaining frame 2 is in a shrinking shape from the outside to the inside, there is a stepped gap that gradually decreases from large to small when looking from the outside to the inside as Figure 5 . This gap can be used to make the positioning of the dispensing holes of the lens 5 to be cured more accurate. Since the gap is processed as small as possible, the dispensing holes can be easily placed at the center of the groove opening with the naked eye.

[0038] The ultraviolet rays from the UV curing machine 6 can be transmitted to the UV optical head 4 through the optical cable. The ultraviolet rays focused by the UV optical head 4 can irradiate the dispensing holes of the lens 5 to be cured. The UV glue in the dispensing holes is cured after being irradiated by the ultraviolet rays to fix the lens or the lens elements; three UV optical heads 4 are evenly distributed at 120° and fixed on the UV fixing frame 3 as Figure 6 . When the UV fixing frame 3 is moved, the three UV optical heads 4 can be moved simultaneously, with accurate positioning and convenient adjustment. Moreover, the three UV optical heads 4 can also be adjusted from the outside to the inside along the radial direction of the middle retaining frame 2 as Figure 6 . The curing distance can be controlled. Since the cooperation between the middle retaining frame 2 and the UV fixing frame 3 is a rail fit as Figure 7 , when the UV fixing frame 3 is adjusted, the three UV optical heads 4 will not move along the outer diameter direction of the middle retaining frame 2, resulting in poor curing.

[0039] After the UV fixing ring 3 is installed with the UV optical head 4, the UV fixing ring 3 is adjusted up and down along the middle retaining frame 2. By adjusting the UV fixing ring 3, the UV optical head 4 is aligned with the dispensing point position of the lens 5 to be cured. In the camera lens production line, the UV fixing ring 3 is manually moved up and down along the guide rail of the middle retaining frame 2, and the adjustment range is 0 - 50 mm, which is suitable for lens assemblies with different heights (such as a three-layer stacked lens group). The operator manually aligns the focal position of the UV optical head 4 with the dispensing hole (diameter 0.3 mm) on the outer diameter of the lens barrel,

[0040] At least two groups of dispensing holes are provided on the outer diameter of the lens 5 to be cured. Each group of dispensing holes has at least 3 holes arranged in a circular array along the outer diameter. When fixing, the holes arranged up and down in the two groups of dispensing holes are cured simultaneously.

[0041] The outer diameter of the lens 5 to be cured is designed with two groups of annular dispensing holes (3 holes in the upper group and 3 holes in the lower group, evenly distributed at intervals of 120°), with a hole diameter of 0.4 mm and a depth of 0.8 mm, for fixing the lens and the aluminum alloy lens barrel. During UV curing, UV glue is injected into the two groups of dispensing holes simultaneously, and dispensing is carried out synchronously by a six-axis robotic arm. Subsequently, the upper and lower linkage curing mode of the three UV lamps 4 is started: the upper UV lamp irradiates the upper row of dispensing holes at an inclination angle of 30°, and the lower UV lamp covers the lower row of dispensing holes at an inclination angle of 45°. The light intensity distribution is monitored in real time by a spot analyzer.

[0042] For example, when curing a Φ18 mm wide-angle lens, the upper and lower dispensing holes simultaneously receive ultraviolet light with an energy density of 80 mW / cm 2 . The curing time of the glue layer with a thickness of 50 μm is shortened from 20 seconds of single-point irradiation to 8 seconds, and the shear strength test value is increased from 12 MPa to 18 MPa. This design effectively avoids the stress concentration problem caused by single-point curing and eliminates the risk of lens tilt through synchronous curing of the upper and lower glue layers.

[0043] The UV curing machine 6 cures the dispensing of the lens 5 to be cured through ultraviolet light. The ultraviolet light is transmitted from the UV curing machine 6 to the UV lamp 4 through an optical cable. The ultraviolet light focused by the UV lamp 4 irradiates the dispensing holes of the lens 5 to be cured. The UV glue in the dispensing holes is cured after being irradiated by the ultraviolet light to fix the lens or the lens in the lens. In lens production, the UV curing machine 6 transmits 365 nm ultraviolet light to the focusing lens group of the UV lamp 4 through a quartz fiber bundle. The UV lamp 4 integrates a collimating mirror and a condenser lens inside, compresses the input light beam with a divergence angle of 22° into a collimated output of 5°, and the spot energy density reaches 250 mW / cm 2 . When irradiating the dispensing holes of the lens barrel, the diameter of the spot coverage area is 0.6 mm, and the light intensity gradient from the edge to the center is ≤10%, ensuring that the glue layer is completely cured within 10 seconds. Compared with traditional mercury lamp curing, this solution saves 60% of energy and avoids the brittle fracture problem caused by over-curing of the glue layer.

[0044] There are three UV optical heads 4, which are arranged in a circular array around the center point of the UV fixing ring 3 on the side surface of the UV fixing ring 3. When the UV fixing ring 3 moves, the three UV optical heads 4 move and position synchronously, and the curing distance is adjusted and controlled from the outside to the inside in the radial direction of the middle holding frame 2 by the three UV optical heads 4 synchronously. In the multi-station curing production line of spectacle lenses, the three UV optical heads 4 (arranged in a 120° circular pattern, with a radial adjustment range of 0-20 mm) achieve synchronous radial movement through a harmonic reducer linkage mechanism, and the positioning accuracy is ±0.005 mm. When processing a free-form surface lens with a diameter of Φ25 mm, the UV fixing ring 3 drives the three optical heads to move inward synchronously by 7.5 mm, so that the center of the light spot is accurately matched with the curved surface glue groove on the outer edge of the lens. Each UV optical head 4 is equipped with an independent light intensity controller, which adaptively adjusts the output power in the curved surface area to ensure the uniformity of the cured glue layer throughout the circumference. Compared with the single UV head rotation scanning scheme, the synchronous irradiation of the three optical heads reduces the time to 12 seconds, and the standard deviation of the curved surface bonding strength decreases from 3.2 MPa to 0.8 MPa.

[0045] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An optical lens UV curing device, characterized in that: The invention comprises an upper cover (1), a middle holding frame (2), a UV fixing ring (3), a UV light head (4), a lens to be cured (5) and a UV curing machine (6). The middle holding frame (2) is arranged below the upper cover (1). The UV fixing ring (3) is installed on the lower side of the middle holding frame (2). One end of the UV light head (4) is connected to a side opening of the UV fixing ring (3), and the other end is connected to the UV curing machine (6) through an optical cable. After the upper cover (1) is opened, the lens to be cured (5) is placed in the middle of the middle holding frame (2). The inner wall of the middle holding frame (2) is provided with a plurality of circular grooves of the same height from top to bottom in a stepped shape from top to bottom. The position of the lens to be cured (5) is fixed by the circular grooves. After the position of the lens to be cured (5) is fixed, the glue hole on the outer diameter of the lens to be cured (5) is aligned with the center of the notch of the middle holding frame (2).

2. An optical lens UV curing device as claimed in claim 1, characterized in that: After the UV light head (4) is installed on the UV fixing ring (3), the UV fixing ring (3) is adjusted up and down along the middle retaining frame (2). By adjusting the UV fixing ring (3), the UV light head (4) and the glue dispensing point of the lens (5) to be cured are aligned.

3. The optical lens UV curing device according to claim 1, characterized in that: At least two groups of glue spots are arranged on the outer diameter of the lens (5) to be cured, and each group of glue spots has at least three holes in a circular array along the outer diameter. When fixing, the holes of the two groups of glue spots arranged up and down are cured simultaneously.

4. The optical lens UV curing device according to claim 1, characterized in that: The UV curing machine (6) cures the glue of the lens to be cured (5) by means of ultraviolet light. The ultraviolet light is transmitted from the UV curing machine (6) to the UV light head (4) via an optical cable. The ultraviolet light focused by the UV light head (4) is irradiated onto the glue spotting hole of the lens to be cured (5). The UV glue in the glue spotting hole is cured after being irradiated by ultraviolet light to fix the lens or the lens in the lens.

5. The optical lens UV curing device according to claim 1, characterized in that: The three UV light heads (4) are arranged in a circular array around the center point of the UV fixing ring (3) and on the side end surface of the UV fixing ring (3); when the UV fixing ring (3) moves, the three UV light heads (4) move and position synchronously; and the three UV light heads (4) are synchronously adjusted with the radial direction of the middle holding frame (2) from outside to inside to control the curing distance.

Images