Micro-lens array, its molding method and application

Abstract

The application provides a microarray lens, a molding method thereof and an application. The microarray lens molding method comprises the following steps: providing a hot-pressing device, which comprises a vacuum cover, an upper pressing plate, a lower bottom plate, a mold and a vacuum pumping module; the upper pressing plate and the lower bottom plate are oppositely arranged in the vacuum cover; the mold is arranged on the lower bottom plate; the mold comprises an upper mold core and a lower mold core which are oppositely arranged, and a cavity is formed between the upper mold core and the lower mold core; and a preform is arranged in the cavity; the lower bottom plate drives the mold to move towards the upper pressing plate, and heating treatment is performed; meanwhile, based on the displacement of the lower bottom plate, the vacuum pumping module is triggered to start and stop, and rough pumping, one-stage fine pumping and two-stage fine pumping are sequentially performed. The application significantly improves the lens mass production efficiency, greatly reduces the large-scale manufacturing cost, and improves the lens production yield and optical quality through multi-stage vacuum fractional pumping.

Description

Technical Field

[0001] This invention belongs to the field of lens manufacturing technology, and relates to a microarray lens, its molding method and application. Background Technology

[0002] With the rapid development of optoelectronic communication, optics, automobiles, bioengineering, aerospace technology, electronics, and military weaponry, the application of optical lenses is becoming increasingly widespread, and the demand is growing rapidly. Simultaneously, the explosive growth in AI computing power and data center traffic is driving the rapid iteration of optical module speeds from 100G and 400G to 800G, 1.6T, and even 3.2T. New architectures such as co-packaged optics (CPO), silicon photonics integration, and optical circuit switching (OCS) are being rapidly implemented, placing unprecedentedly stringent requirements on optical coupling components. In the consumer electronics sector, while pursuing miniaturization of lenses for mobile phones and digital cameras, consumers are also demanding higher image quality.

[0003] Currently, there are three main technical routes for microlens arrays used in optical communication: semiconductor etched silicon lenses, polymer injection molded arrays, and glass precision molding arrays. Among them, glass precision molding technology, by pressing softened glass blanks into ultra-precision molds, can obtain aspherical array structures that meet optical precision in one step. It combines the high environmental reliability of optical glass with the mass production efficiency of array processes, and is the mainstream technology direction in the current optical communication field that combines performance and cost advantages.

[0004] However, traditional glass precision molding technology suffers from slow production cycles and low efficiency. Furthermore, in mass production, even minor fluctuations in process parameters can lead to instability in the product's surface shape and profile, resulting in a lower yield. Therefore, ensuring the optical performance of the product while achieving high-efficiency, low-cost mass production is a pressing issue that needs to be addressed. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a microarray lens, its molding method and application. By performing staged vacuuming during the hot pressing process, the negative pressure establishment speed is accelerated, the product yield is improved, and the optical quality of the lens is also effectively enhanced.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a microarray lens molding method, providing a hot pressing molding apparatus, which includes a vacuum chamber, an upper pressure plate, a lower base plate, a mold, and a vacuum extraction module. The upper pressure plate and the lower base plate are placed opposite each other in the vacuum chamber, and the vacuum extraction module is connected to the vacuum chamber. The mold is placed on the lower base plate, and the mold includes an upper mold core and a lower mold core arranged opposite each other, forming a cavity between the upper mold core and the lower mold core, and placing the preform in the cavity. The lower base plate is driven to move the mold closer to the upper pressure plate and perform heat treatment; Simultaneously, based on the displacement of the lower base plate, the vacuum module is triggered to start and stop, and coarse evacuation, first-stage fine evacuation and second-stage fine evacuation are performed in sequence.

[0007] As a preferred embodiment of the present invention, the preform is at least one of spherical, biconvex, and flat.

[0008] As a preferred embodiment of the present invention, the vacuuming module includes a fine vacuuming module and a coarse vacuuming module.

[0009] As a preferred embodiment of the present invention, the microarray lens molding method includes the following steps: S1: Place the preform on the side of the lower mold core close to the upper mold core, drive the lower bottom plate to move towards the side close to the upper pressure plate, and start heating simultaneously. At the same time, both the fine vacuum module and the coarse vacuum module are in the closed state. S2: When the lower base plate moves to the mold closing position height, start the rough vacuum module and drive the lower base plate to continue moving, and perform rough vacuuming simultaneously. S3: After the lower base plate moves a set safe distance and comes to a stop, the coarse vacuum module is turned off, and the fine vacuum module is turned on to perform a fine vacuuming. S4: Drive the lower base plate to move closer to the upper mold core again and continue heating to fully soften the preform; S5: The lower base plate continues to move until the preform meets the set forming thickness. The lower base plate stops again and heating stops. At the same time, the fine vacuum module performs a second-stage fine vacuuming and maintains constant temperature and pressure, and then cools and forms. S6: Separate the upper mold core from the lower mold core, remove the sample, and obtain the microarray lens.

[0010] As a preferred embodiment of the present invention, after the coarse pumping setting is completed, the vacuum level inside the vacuum chamber is <0.6 MPa.

[0011] As a preferred embodiment of the present invention, after the completion of the first stage of fine evacuation, the set vacuum level inside the vacuum chamber is 0.1~0.3 MPa.

[0012] In one embodiment of the present invention, after the two-stage fine evacuation is completed, the vacuum degree inside the vacuum chamber is <0.1 MPa.

[0013] As a preferred embodiment of the present invention, in step S2, after the lower base plate reaches the mold closing position height, the speed at which it continues to move is 2~4 mm / s.

[0014] In one embodiment of the present invention, in step S3, the static time of the lower base plate is 10~25s.

[0015] In one embodiment of the present invention, in step S3, the safety distance is ≥0.5mm.

[0016] In one embodiment of the present invention, in step S4, the speed at which the lower base plate moves is 0.8~1.3 mm / s.

[0017] As a preferred embodiment of the present invention, in step S4, the heating temperature is 650~680℃.

[0018] In one embodiment of the present invention, in step S5, the constant temperature and pressure holding time is 10~20s.

[0019] In a second aspect, the present invention provides a microarray lens, which is manufactured by the molding method described in the first aspect; the microarray lens has CpK≥1.67, roughness Ra<5nm, surface accuracy RMS≤30nm, and focal length deviation<0.3%.

[0020] Thirdly, the present invention provides an application of the microarray lens described in the second aspect, wherein the microarray lens is used in vehicle HUD (Head-Up Display), mobile phone lens or optical communication device.

[0021] The system refers to an equipment system, device system, or production device.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention does not start the vacuum pumping unit during the unloaded descent stage, but only pumps air in stages after the mold surface is sealed, which greatly shortens the continuous working time of high vacuum, reduces the wear and oil and gas consumption of vacuum equipment, and increases the equipment maintenance cycle by more than 40%, avoiding the ineffective energy consumption and continuous heat generation failure of the unit caused by full vacuum. (2) The present invention uses the displacement point as the vacuum start-stop trigger logic. Only after the parting surface is fully attached is a negative pressure established, eliminating the vacuum fluctuation caused by mold gap leakage during the downward process. It solves the problems of mold surface suction offset and mold core alignment deviation caused by early vacuuming in the traditional process, and greatly improves the consistency of pressure difference in the multi-cavity forming cavity of a mold. (3) After the cavity is sealed, the gap air is fully removed, and the vacuum degree can reach 0.6Pa level oxygen-free environment, eliminating the oxidation of high temperature glass and residual air and air bag defects, which increases the yield of microlens array and large-diameter aspherical lens by 15%~25% and greatly reduces the polishing rework cost. (4) The negative pressure environment formed during the molding process of this invention eliminates the gas buffer resistance, so that the molding pressure is uniformly transmitted to the entire substrate, which significantly improves the lens surface accuracy and dimensional consistency. (5) The present invention adopts staged air extraction to maintain high vacuum and isolate oxygen throughout the molding and pressure holding process, ensuring that the hard coating of the mold core is free from oxidation and ablation at high temperature, reducing the frequency of mold core polishing and repair, and increasing the service life of the mold by more than 30%, which is suitable for long-term mass production of high-precision tungsten steel and ceramic mold cores. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a hot pressing molding apparatus for molding spherical preforms.

[0024] Figure 2 This is a schematic diagram of a hot pressing molding apparatus for molding a biconvex preform.

[0025] Figure 3 This is a schematic diagram of a hot pressing molding apparatus for molding flat preforms.

[0026] Figure 4 This is a graph showing the trend of displacement of the upper mold core.

[0027] Among them, 1-vacuum cover; 2-upper mold core; 3-lower mold core; 4-preform; 5-upper pressure plate; 6-lower base plate. Detailed Implementation

[0028] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0029] The scope of this invention can be defined by lower and upper limits. The selected lower and upper limits define the boundaries of a specific range. The range defined in this way can be defined by the inclusion or exclusion of endpoints. Any endpoint can be independently selected for inclusion or exclusion, and all lower and upper limits can be arbitrarily combined to form new ranges. That is, any lower limit can be combined with any upper limit to form an effective range. For example, if the ranges of 60~120 and 80~110 are listed for specific parameters, it should be understood that the ranges of 60~110 and 80~120 also fall within the scope of this invention. In addition, if the minimum range values ​​1 and 2 are listed, and the maximum range values ​​3, 4 and 5 are also listed, then all ranges of 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5 fall within the scope of this invention. In this invention, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between 0 and 5 have been fully listed in this document, and "0~5" is only a shortened representation of this set of numerical combinations. When a parameter is expressed as an integer ≥2, it is equivalent to listing positive integers that meet the requirements, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. When a parameter is expressed as an integer selected from "2~10", it is equivalent to listing any integer among 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0030] In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B.

[0031] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention. The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. Those skilled in the art can understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments that do not conflict with the technology.

[0032] In this invention, the order in which the steps are written in the methods described in each embodiment does not imply a strict execution order. The actual execution order of each step should be determined based on its function and possible internal logic. Unless otherwise specified, all steps of this invention can be executed in the order they are written, or in any order without technical conflict. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) executed sequentially, or it may include steps (b) and (a) executed sequentially. If the method also includes step (c), then step (c) can be added to the method in any order without conflict, including but not limited to the execution order of steps (a), (b), and (c), steps (a), (c), and (b), steps (c), (a), and (b), etc.

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0034] In one specific embodiment, the present invention provides a microarray lens molding method, comprising: Provide such as Figures 1-3 The hot pressing forming apparatus shown; The hot pressing forming device includes a vacuum chamber 1, an upper pressure plate 5, a lower base plate 6, a mold, and a vacuum extraction module. The upper pressure plate 5 and the lower base plate 6 are placed opposite each other inside the vacuum chamber, and the vacuum extraction module is connected to the vacuum chamber. The mold is placed on the lower base plate 6, and the mold includes an upper mold core 2 and a lower mold core 3 arranged opposite each other, forming a cavity between the upper mold core 2 and the lower mold core 3, and the preform 4 is placed in the cavity. The lower base plate 6 is driven to move the mold closer to the upper pressure plate 5 and perform heat treatment; Simultaneously, based on the displacement of the lower base plate 6, the vacuum module is triggered to start and stop, and coarse evacuation, first-stage fine evacuation and second-stage fine evacuation are performed in sequence.

[0035] In the hot pressing forming apparatus of the present invention, the upper mold core 2 and the lower mold core 3 are made of tungsten steel or ceramic, and their outer surfaces are coated with a hard coating, including but not limited to titanium nitride coating, chromium nitride coating, diamond-like carbon coating or titanium carbonitride coating, etc.

[0036] The upper mold core 2 and the lower mold core 3 have independently arranged grooves in an array on their opposite side surfaces to form a micro array lens.

[0037] In one embodiment, the mold further includes a sleeve located inside the vacuum chamber 1, and the lower mold core 3 is inserted into the sleeve from one end, the upper mold core 2 extends into the sleeve from the other end, and forms the cavity between the upper mold core 2 and the lower mold core 3, and the preform 4 fills the cavity after being heated and softened.

[0038] The vacuum chamber 1 is a sealed chamber. The vacuum pumping device evacuates the vacuum chamber 1, thereby creating a negative pressure environment between the upper mold core 2 and the lower mold core 3. The materials of the vacuum chamber 1 include, but are not limited to, plexiglass, polycarbonate, stainless steel, aluminum alloy, etc.

[0039] The vacuuming device uses equipment known in the art, which necessarily includes a vacuum pump, necessary pipelines, control valves, etc., required to achieve complete process operation. This invention does not impose any special limitations on these components. Those skilled in the art should reasonably adjust, add, or delete components according to actual production needs. It should be noted that new technical solutions generated by deleting some unnecessary connecting pipelines and switch control valves, replacing single-function switch control valves with multi-function integrated control valves, or using external automatic control systems electrically connected to the switch control valves to control the opening of the corresponding valves, etc., which are common and well-known technical means used by those skilled in the art, also fall within the scope of disclosure and protection of this invention.

[0040] In one implementation, the vacuum module includes a fine vacuum module and a coarse vacuum module, which are independently connected to the vacuum chamber 1 and used for coarse and fine vacuuming, respectively.

[0041] The hot pressing forming device also includes a drive module and a heating module necessary to achieve complete process; the drive module is used to drive the lower base plate 6 to move, and the heating module is used to heat the preform 4.

[0042] The material of the preform 4 described in this invention is glass, and those skilled in the art can select the appropriate material according to actual needs.

[0043] In some implementations, such as Figure 1 As shown, the preform 4 is spherical, and after softening upon heating, it undergoes symmetrical deformation under pressure. The radial flow distance of the material is extremely short, resulting in uniform stress during cavity filling. The microstructure contour replication fidelity can reach over 99.5%, and the RMS accuracy of the finished lens surface can be stably controlled within 30nm, perfectly matching the nanometer-level precision requirements of aspherical lenses for optical communication. Simultaneously, the weight deviation of a single spherical preform 4 can be controlled within ±0.2%, and the material supply to each cavity is highly consistent, eliminating inter-channel volume deviations from the source. Combined with a radially homogenized mold, the focal length deviation within the array can be less than 0.3%, and the channel insertion loss difference ≤0.15dB, improving array consistency. In addition, the spherical preform 4 has low residual stress. During the molding process, it is only a small deformation reshaping from the spherical surface to the target curved surface. There is no large-scale material shear flow. The stress distribution is symmetrical and uniform. After in-situ annealing, the residual stress birefringence can be lower than 8 nm / cm. After temperature cycling from -40℃ to +85℃, the focal length drift is less than 0.08%, which is highly reliable.

[0044] In some implementations, such as Figure 2 As shown, the preform 4 is biconvex, with a single blank weight deviation of about ±0.5%. The uniformity of optical parameters between channels is slightly inferior to that of the spherical preform 4. It is suitable for lens structures with high sagittal height and can also be used as a selection for large-aperture optical communication lens arrays.

[0045] In some implementations, such as Figure 3 As shown, the preform 4 is flat and suitable for array lens structures with convex surfaces. The manufacturing process is simple and the thickness is controllable.

[0046] In some implementations, as such Figure 4 The moving path of the lower base plate 6 shown, and the microarray lens molding method include the following steps: S1: Place the preform 4 on the side of the lower mold core 3 near the upper mold core 2, drive the lower base plate 6 to move towards the side near the upper pressure plate 5, and start heating simultaneously. At the same time, both the fine vacuum module and the coarse vacuum module are in the off state. That is, in the no-load descent phase, the vacuum module is not activated, which greatly shortens the continuous high vacuum working time and reduces vacuum pump wear and oil and gas consumption.

[0047] S2: When the lower base plate 6 reaches the mold closing position height, the coarse vacuum module is activated, and the lower base plate 6 continues to move, simultaneously performing coarse vacuuming. After the coarse vacuuming is completed, the vacuum level inside the vacuum chamber is <0.6 MPa. At this time, the lower base plate 6 and the upper base plate are not in contact and there is still a gap. The coarse vacuuming is used to quickly remove air trapped in the gap between the cavity and the preform 4. After the lower base plate 6 reaches the mold closing position height, its continuing movement speed is 2~4 mm / s, for example, it can be 2 mm / s, 2.5 mm / s, 3 mm / s, 3.5 mm / s or 4 mm / s, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0048] S3: After the lower base plate 6 moves a set safety distance and comes to a stop, the coarse vacuum module is turned off, and the fine vacuum module is turned on to perform a fine vacuuming operation. This invention performs a fine vacuuming operation after the coarse vacuuming, significantly improving the overall sealing reliability and eliminating negative pressure leakage defects. After the fine vacuuming operation, the set vacuum level inside the vacuum chamber is 0.1~0.3 MPa, for example, 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa, or 0.3 MPa, but not limited to the listed values; other unlisted values ​​within this range are also applicable. The stationary time of the lower base plate 6 is 10~25 seconds, for example, 10 seconds, 12 seconds, 15 seconds, 18 seconds, 20 seconds, 22 seconds, or 25 seconds, but not limited to the listed values; other unlisted values ​​within this range are also applicable. The safety distance is ≥0.5 mm.

[0049] S4: Drive the lower base plate 6 to move closer to the upper mold core 2 again and continue heating to fully soften the preform 4. The moving speed of the lower base plate 6 is 0.8~1.3mm / s, for example, it can be 0.8mm / s, 0.8mm / s, 0.9mm / s, 1.0mm / s, 1.1mm / s, 1.2mm / s or 1.3mm / s, but is not limited to the listed values; other unlisted values ​​within this range are also applicable. The continuous heating temperature is 650~680℃, for example, it can be 650℃, 660℃, 670℃ or 680℃, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0050] S5: The lower base plate 6 continues to move until the preform 4 reaches the set molding thickness. The lower base plate 6 then comes to a standstill, heating stops, and the precision vacuum module performs a second-stage precision vacuuming and constant-temperature pressure holding, followed by cooling and molding. At this time, the upper mold core 2 and the lower mold core 3 are tightly fitted together, and the rapid establishment of the negative pressure environment ensures a constant high vacuum without pressure loss. The constant-temperature pressure holding time is 10~20s, for example, it can be 10s, 11s, 12s, 13s, 14s, 15s, 16s, 17s, 18s, or 20s, but is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0051] S6: Separate the upper mold core 2 from the lower mold core 3, remove the sample, and obtain the microarray lens.

[0052] The molding method of this invention realizes vacuum molding in the molding cavity, which greatly improves the uniformity and yield of array molding. Through multi-stage vacuum staged evacuation, the negative pressure establishment speed is accelerated. At the same time, by using a coarse evacuation + fine evacuation dual-stage vacuum module, the standard process vacuum degree is reached within a few seconds after the upper mold core 2 and the lower mold core 3 are sealed together, which greatly shortens the single cycle time and can be adapted to high-speed continuous mass production, solving the problems of slow evacuation and insufficient vacuum degree of single-stage vacuum equipment.

[0053] In another specific embodiment, the present invention provides a microarray lens, which is manufactured by the molding method described in a specific embodiment; the microarray lens has CpK≥1.67, roughness Ra<5nm, surface accuracy RMS≤30nm, and focal length deviation<0.3%.

[0054] The microarray lens of this invention meets the requirements of different application fields for array lens forming accuracy, channel consistency and long-term reliability, and can be applied to vehicle HUD, mobile phone lens or optical communication equipment.

[0055] Example 1 This embodiment provides a microarray lens and its molding method. The spherical preform 4 is molded using the aforementioned hot pressing molding device, specifically including the following steps: (1) Place the spherical preform 4 on the side of the lower mold core 3 close to the upper mold core 2, drive the lower base plate 6 to move to the side close to the upper base plate, and start heating simultaneously. At the same time, the fine vacuum module and the coarse vacuum module are both in the closed state, which greatly shortens the continuous working time of high vacuum and reduces the wear of vacuum pump and oil and gas consumption. (2) When the lower base plate 6 moves to the mold closing position height, start the rough vacuum module and drive the lower base plate 6 to continue moving at a speed of 2 mm / s, and perform rough vacuuming simultaneously; after the rough vacuuming is completed, the vacuum degree in the vacuum chamber is <0.6 MPa. At this time, the lower base plate 6 and the upper base plate are not in contact and there is still a gap. Through rough vacuuming, the air trapped in the gap between the cavity and the preform 4 can be quickly discharged. (3) After the bottom plate 6 moves another 0.6mm and stops for 10~25s, the coarse vacuum module is closed and the fine vacuum module is opened to perform a fine vacuum, so that the vacuum degree in the vacuum chamber reaches 0.1~0.3Mpa, the overall sealing reliability is significantly improved, and the negative pressure leakage defect is eliminated. (4) Drive the lower base plate 6 to move closer to the upper mold core 2 at a speed of 1.0 mm / s and continue to heat it to 660°C to fully soften the preform 4; (5) The lower base plate 6 continues to move until the preform 4 meets the set forming thickness. The lower base plate 6 stops again and the heating stops. At the same time, the fine vacuum module performs a second-stage fine vacuuming and maintains constant temperature and pressure for 20 seconds. Then it cools and forms. At this time, the upper mold core 2 and the lower mold core 3 are tightly fitted together. The rapid establishment of the negative pressure environment ensures that the high vacuum state is maintained throughout the process without pressure leakage. (6) Separate the upper mold core 2 from the lower mold core 3, remove the sample, and obtain the micro array lens.

[0056] The microarray lens prepared in this embodiment has a CpK ≥ 1.67, a roughness Ra < 5 nm, a surface accuracy RMS ≤ 30 nm, and a focal length deviation < 0.3%.

[0057] Example 2 This embodiment provides a microarray lens and its molding method. The difference from Embodiment 1 is that the preform 4 adopts a biconvex preform 4, while the other preparation steps and process parameters are the same as in Embodiment 1.

[0058] Example 3 This embodiment provides a microarray lens and its molding method. The difference from Embodiment 1 is that the preform 4 is a flat preform 4, while the other preparation steps and process parameters are the same as in Embodiment 1.

[0059] The yield of the microarray lenses prepared in Examples 1 to 3 was tested in this invention, and the results are shown in Table 1.

[0060] Table 1 As can be seen from Table 1, Example 1 exhibits the best surface accuracy and array consistency. This is mainly due to the symmetrical deformation of the spherical preform 4 after heating and softening, resulting in a very short radial material flow distance and uniform stress during cavity filling. Furthermore, the forming process of the spherical preform 4 involves only small deformation reshaping from the spherical surface to the target curved surface, without large-scale material shear flow, leading to a symmetrical and uniform stress distribution and thus improving its overall performance. In contrast, Example 2 uses a biconvex preform 4, whose optical parameter uniformity between channels is slightly inferior, resulting in lower consistency than Example 1. In Example 3, the flat preform 4, during hot pressing, introduces significant shear stress due to the large-scale viscous flow of material. After annealing, the residual stress distribution is uneven, and the focal length drift is large during temperature cycling, leading to lower consistency and reliability than Example 1.

[0061] Comparative Example 1 This comparative example provides a microarray lens and its molding method. The difference from Example 1 is that the hot pressing molding device used is equipped with only a single vacuum module, and the vacuum module is simultaneously activated to perform vacuuming throughout the entire process when the lower base plate 6 starts to move. The remaining method steps are the same as in Example 1.

[0062] Compared to the full-process vacuuming scheme of a single vacuuming module in Comparative Example 1, Example 1 uses a dual-stage vacuum module of coarse and fine vacuuming for multi-stage vacuum evacuation, which significantly improves the overall performance of the microarray lens. This is because Example 1 does not activate the vacuum unit during the unloaded ascent stage of the lower base plate 6, but only establishes negative pressure after the parting surface is fully aligned. This eliminates vacuum fluctuations caused by air leakage in the mold seam during the descent process, eliminates mold surface suction offset and mold core alignment deviation, and the negative pressure environment eliminates gas buffer resistance, allowing the molding pressure to be evenly transmitted to the entire preform 4. At the same time, after the cavity is sealed, the gap air is fully evacuated, and the vacuum level can reach 0.6Pa level oxygen-free environment, which completely eliminates bubbles, air marks, and optical defects, thereby improving the optical quality of the microarray lens.

[0063] This invention significantly shortens the continuous working time of the high vacuum pump through segmented vacuum control, and uses the displacement point as the vacuum start-stop trigger logic, which improves the sealing reliability of the mold, eliminates negative pressure leakage defects, inhibits mold core oxidation, extends the service life of precision molds, and completely eliminates defects such as bubbles, air marks, and optical imperfections, resulting in a significant improvement in the surface accuracy and dimensional consistency of the lens.

[0064] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A micro-lens array molding method characterized by comprising: The microarray lens molding method includes: A hot pressing forming apparatus is provided, comprising a vacuum chamber, an upper pressure plate, a lower base plate, a mold, and a vacuum extraction module. The upper pressure plate and the lower base plate are placed opposite each other inside the vacuum chamber, and the vacuum extraction module is connected to the vacuum chamber. The mold is placed on the lower base plate and includes an upper mold core and a lower mold core arranged opposite each other, forming a cavity between the upper mold core and the lower mold core, and a preform is placed inside the cavity. The lower base plate is driven to move the mold closer to the upper pressure plate and perform heat treatment; Simultaneously, based on the displacement of the lower base plate, the vacuum module is triggered to start and stop, and coarse evacuation, first-stage fine evacuation and second-stage fine evacuation are performed in sequence.

2. The microarray lens molding method according to claim 1, characterized in that, The preform is at least one of spherical, biconvex, and flat.

3. The microarray lens molding method according to claim 1 or 2, characterized in that, The vacuuming module includes a fine vacuuming module and a coarse vacuuming module.

4. The microarray lens molding method according to claim 3, characterized in that, The microarray lens molding method includes the following steps: S1: Place the preform on the side of the lower mold core close to the upper mold core, drive the lower bottom plate to move towards the side close to the upper pressure plate, and start heating simultaneously. At the same time, both the fine vacuum module and the coarse vacuum module are in the closed state. S2: When the lower base plate moves to the mold closing position height, start the rough vacuum module and drive the lower base plate to continue moving, and perform rough vacuuming simultaneously. S3: After the lower base plate moves a set safe distance and comes to a stop, the coarse vacuum module is turned off, and the fine vacuum module is turned on to perform a fine vacuuming. S4: Drive the lower base plate to move closer to the upper mold core again and continue heating to fully soften the preform; S5: The lower base plate continues to move until the preform meets the set forming thickness. The lower base plate stops again and heating stops. At the same time, the fine vacuum module performs a second-stage fine vacuuming and maintains constant temperature and pressure, and then cools and forms. S6: Separate the upper mold core from the lower mold core, remove the sample, and obtain the microarray lens.

5. The microarray lens molding method according to claim 4, characterized in that, After the roughing process is completed, the vacuum level inside the vacuum chamber is <0.6 MPa.

6. The microarray lens molding method according to claim 4 or 5, characterized in that, After the aforementioned fine evacuation is completed, the vacuum level inside the vacuum chamber is 0.1~0.3 MPa; And / or, after the two-stage fine evacuation is completed, the vacuum level inside the vacuum chamber is <0.1 MPa.

7. The microarray lens molding method according to any one of claims 4-6, characterized in that, In step (2), after the lower base plate reaches the mold closing position height, it continues to move at a speed of 2~4 mm / s; And / or, in step S3, the resting time of the lower base plate is 10~25s; And / or, in step S3, the safety distance is ≥0.5mm; And / or, in step S4, the speed at which the lower base plate moves is 0.8~1.3 mm / s.

8. The microarray lens molding method according to any one of claims 4-6, characterized in that, In step S4, the heating temperature is 650~680℃; And / or, in step S5, the constant temperature and pressure holding time is 10~20s.

9. A microarray lens, characterized in that, The microarray lens is manufactured using the molding method described in any one of claims 1-8; the microarray lens has a CpK ≥ 1.67, a roughness Ra < 5nm, a surface accuracy RMS ≤ 30nm, and a focal length deviation < 0.3%.

10. An application of the microarray lens according to claim 9, characterized in that, The microarray lens is used in vehicle HUDs, mobile phone lenses, or optical communication devices.

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