Focusing ultraviolet macro lens

Abstract

The invention discloses a focusable ultraviolet macro lens, which comprises a lens mount, a focusing ring, a fixed lens group, a movable lens group and an imaging sensor, and is characterized in that the fixed lens group and the movable lens group are sequentially arranged in the lens mount from an object side to an image side along an optical axis, and the focusing ring is connected with the movable lens group; the movable lens group moves along an optical axis to realize focal length adjustment; the fixed lens group comprises a first lens and a second lens which are sequentially arranged from the object side to the image side; the moving lens group comprises a third lens, a fourth lens and a fifth lens which are sequentially arranged from the object side to the image side; the surfaces of the first lens to the fifth lens are plated with ultraviolet antireflection films. Through the five-piece lens structure combining the fixed lens group and the movable lens group, the focal length is continuously adjustable, the fused quartz and calcium fluoride materials are matched with the ultraviolet antireflection film, the ultraviolet band imaging quality and the focusing stability are improved, and the lens is suitable for semiconductor defect detection, micro part imaging, biological microstructure observation and other scenes.

Description

Technical Field

[0001] This application relates to an adjustable-focus ultraviolet macro lens, belonging to the field of optical lens technology. Background Technology

[0002] In the field of microscopic inspection, ultraviolet (UV) macro lenses are key optical components in applications such as semiconductor defect detection, micro-part imaging, and observation of biological microstructures. Currently, the commonly used technology in this field employs UV-band optical lenses, with operating wavelengths primarily concentrated in the 300nm-400nm range. These lenses achieve light convergence and imaging through a combination of multiple lenses. Existing UV macro lenses typically use optical materials with high UV transmittance, such as fused silica and calcium fluoride, to fabricate the lenses, and an anti-reflection coating is deposited on the lens surface to enhance UV transmittance. In terms of structural design, most existing lenses employ a fixed lens group, with the lenses fixedly mounted within the lens mount along the optical axis. Some products are equipped with a focusing mechanism to achieve focal length adjustment, using methods such as threaded connections, gear transmission, or electric drive. The imaging sensor is located on the image side of the lens to receive optical signals.

[0003] However, the current problems are: most existing ultraviolet macro lenses are fixed-focus designs, which cannot flexibly adjust the focal length to meet the needs of detecting microscopic targets of different distances and sizes; some ultraviolet lenses with focusing functions use complex focusing mechanisms, resulting in a large overall size and insufficient focusing accuracy, making it difficult to meet the requirements of high-precision microscopic detection; at the same time, the existing adjustable-focus lenses have poor imaging quality in the ultraviolet band, with large distortion, and the lens group has poor stability during focusing, which is prone to image shift, affecting detection accuracy and imaging consistency. Summary of the Invention

[0004] This invention relates to an adjustable-focus ultraviolet macro lens. The technical problem this invention aims to solve is that: most existing ultraviolet macro lenses are fixed-focus designs, which cannot flexibly adjust the focal length to adapt to the detection needs of microscopic targets of different distances and sizes; some ultraviolet lenses with focusing functions have insufficient focusing accuracy, making it difficult to meet the requirements of high-precision microscopic detection; at the same time, existing adjustable-focus lenses have poor imaging quality in the ultraviolet band, with large distortion, and the lens group has poor stability during focusing, which easily leads to image shift, affecting detection accuracy and imaging consistency.

[0005] To achieve the above objectives, this application provides the following technical solution: This application provides an adjustable focus ultraviolet macro lens, including a lens mount, a focusing ring, a fixed lens group, a movable lens group, and an imaging sensor. The fixed lens group and the movable lens group are sequentially arranged in the lens mount from the object side to the image side along the optical axis. The focusing ring is connected to the movable lens group and is used to adjust the movement of the movable lens group along the optical axis to achieve focal length adjustment. The fixed lens group includes a first lens and a second lens arranged sequentially from the object side to the image side; The movable lens group includes a third lens, a fourth lens, and a fifth lens arranged sequentially from the object side to the image side; The surfaces of the first to fifth lenses are all coated with an ultraviolet anti-reflection film.

[0006] Optionally, the first lens is a negative optical power biconcave spherical lens made of fused silica material; The second lens is a positive optical power biconvex spherical lens made of calcium fluoride material.

[0007] Optionally, the third lens is a positive optical power crescent moon lens, made of fused silica material; The fourth lens is a negative optical power biconcave spherical lens made of calcium fluoride material; The fifth lens is a positive optical power biconvex spherical lens made of fused silica material.

[0008] Optionally, the ultraviolet antireflection film has a wavelength range of 300nm-400nm and a transmittance of ≥85% within the wavelength range.

[0009] Optionally, the focusing ring and the lens mount are connected by a thread, the focusing accuracy is 0.01mm, and the moving lens group has a moving range of 5-10mm, so that the focal length can be adjusted between 20-35mm. Preferably, the focusing ring and the lens mount are connected by a fine thread, and the moving lens group has a moving range of 8mm.

[0010] Optionally, the adjustable-focus ultraviolet macro lens has a numerical aperture of 0.4-0.5, distortion ≤0.1%, and resolution ≥100 line pairs / mm.

[0011] Optionally, it also includes an aperture stop, which is disposed between the fixed lens group and the movable lens group; Preferably, the aperture stop has an aperture of 3 mm, which is used to adjust the amount of light entering the aperture.

[0012] Optionally, the adjustable-focus ultraviolet macro lens is suitable for semiconductor micro-defect detection, ultraviolet imaging of micro-parts, or observation of biological microstructures.

[0013] Optionally, the first lens has a refractive index Nd=1.46 and a dispersion coefficient Vd=67.8; The second lens has a refractive index of Nd=1.43 and a dispersion coefficient of Vd=95.

[0014] Optionally, the third lens has a focal length of 35mm and a center thickness of 3.2mm; The fourth lens has a focal length of -42mm and a center thickness of 2.5mm; The fifth lens has a focal length of 30mm and a center thickness of 3.0mm.

[0015] The beneficial effects that this application can produce include: 1) This application adopts a five-element lens structure that combines a fixed lens group and a moving lens group. The focal length is continuously adjustable by driving the moving lens group along the optical axis through the focusing ring. The focal length adjustment range is 20-35mm, which can flexibly adapt to the needs of micro-target detection at different distances and sizes, and significantly improves the flexibility of lens use.

[0016] 2) This application uses a combination of two optical materials with high ultraviolet transmittance, fused silica and calcium fluoride, combined with an ultraviolet antireflection film in the 300nm-400nm band, with a transmittance of ≥85%, which effectively improves the imaging quality and signal-to-noise ratio in the ultraviolet band.

[0017] 3) The focusing ring and lens mount of this application are connected by fine thread, with a focusing accuracy of 0.01mm and the moving lens group movement range is precisely controlled within 8mm, which ensures the stability and repeatability of the focusing process and avoids image shift.

[0018] 4) The lens of this application has a numerical aperture of 0.4-0.5, distortion ≤0.1%, resolution ≥100 line pairs / mm, and high imaging clarity, which can meet the application requirements of high-precision detection scenarios such as semiconductor micro-defect detection, ultraviolet imaging of micro-parts and observation of biological microstructures.

[0019] 5) This application adjusts the amount of light entering the camera by using an aperture stop, which further optimizes the imaging contrast and depth of field effect. The overall structure is compact and easy to integrate and apply. Attached Figure Description

[0020] Figure 1 A schematic diagram of the overall structure of an adjustable-focus ultraviolet macro lens provided in one embodiment of this application; Figure label: 10- Adjustable focus ultraviolet macro lens; 11-Lens mount; 12-Focusing ring; 13-Fixed lens group; 131-First lens; 132-Second lens; 14-Moving lens group; 141-Third lens; 142-Fourth lens; 143-Fifth lens; 15-Imaging sensor; 16-Aperture stop. Detailed Implementation

[0021] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0022] Existing ultraviolet macro lenses suffer from technical problems such as fixed focal length that cannot be adjusted, insufficient focusing accuracy, and poor imaging quality in the ultraviolet band. There is a need for an adjustable-focus ultraviolet macro lens 10 that can achieve continuously adjustable focal length and excellent imaging quality.

[0023] Therefore, this application provides an adjustable-focus ultraviolet macro lens 10 in one embodiment. The adjustable-focus ultraviolet macro lens 10 includes a lens mount 11, a focusing ring 12, a fixed lens group 13, a movable lens group 14, and an imaging sensor 15. The fixed lens group 13 and the movable lens group 14 are arranged sequentially from the object side to the image side in the lens mount 11 along the optical axis. The focusing ring 12 is connected to the movable lens group 14 and is used to adjust the movement of the movable lens group 14 along the optical axis to achieve focal length adjustment. The fixed lens group 13 includes a first lens 131 and a second lens 132 arranged sequentially from the object side to the image side. The movable lens group 14 includes a third lens 141, a fourth lens 142, and a fifth lens 143 arranged sequentially from the object side to the image side. The surfaces of the first lens 131 to the fifth lens 143 are all coated with an ultraviolet anti-reflection film. The lens mount 11 is made of aluminum alloy and has a precision guide groove inside to guide the lens group to move along the optical axis. The focusing ring 12 is made of stainless steel with an anti-slip knurled texture on the outer surface and a precision thread on the inner surface. The fixed lens group 13 is fixed to the front of the lens mount 11 by a pressure ring and its position is not adjustable. The movable lens group 14 is mounted on a precision slide rail and can be driven to move back and forth along the optical axis by the focusing ring 12. The imaging sensor 15 is a high-sensitivity CCD or CMOS sensor in the ultraviolet band and is installed at the image-side end of the lens mount 11. The first lens 131 to the fifth lens 143 are all optical-grade lenses with precision polished surfaces. Both surfaces of each lens are coated with an ultraviolet anti-reflection film by a vacuum coating process.

[0024] The fixed lens group 13 and the movable lens group 14 together constitute a five-element optical system. Light enters from the object side and is refracted and converged sequentially through the first lens 131 to the fifth lens 143, finally forming a clear image on the imaging sensor 15. When the focusing ring 12 rotates, it drives the movable lens group 14 to move back and forth along the optical axis through a screw drive, changing the spacing between the lens groups, thereby realizing continuous adjustment of the focal length. The ultraviolet anti-reflection coating reduces the reflection loss of light on the lens surface and improves the transmittance in the ultraviolet band.

[0025] This implementation achieves continuous focal length adjustment, with a wide focusing range to adapt to different detection distance requirements; the five-element lens structure optimizes optical performance, the ultraviolet anti-reflection coating improves ultraviolet transmittance, and the imaging quality is excellent; the separate design of the fixed lens group 13 and the movable lens group 14 ensures optical stability during the focusing process.

[0026] As an example, improper material selection for the first lens 131 and the second lens 132 in existing ultraviolet macro lenses can lead to technical problems such as low ultraviolet transmittance and poor chromatic aberration correction. Therefore, it is necessary to optimize the design of the materials and optical power of the first lens 131 and the second lens 132.

[0027] Specifically, the first lens 131 is a negative power biconcave spherical lens made of fused silica; the second lens 132 is a positive power biconvex spherical lens made of calcium fluoride. Both surfaces of the first lens 131 are concave spherical with radii of curvature of -25mm and -30mm respectively, a center thickness of 2.8mm, and an edge thickness of 4.5mm. Fused silica has high ultraviolet transmittance, reaching over 90% in the 300nm-400nm wavelength range, and exhibits a low coefficient of thermal expansion and good temperature stability. Both surfaces of the second lens 132 are convex spherical with radii of curvature of 28mm and 26mm respectively, a center thickness of 3.5mm, and an edge thickness of 2.2mm. Calcium fluoride exhibits excellent transmittance and low dispersion characteristics in the ultraviolet band. The first lens 131 and the second lens 132 are combined using optical adhesive bonding or air gaps to form an achromatic doublet lens structure. In practical applications, other models of this component can also be selected, and this embodiment does not limit this.

[0028] The negative optical power of the first lens 131 causes the incident light to diverge, while the positive optical power of the second lens 132 causes the light to converge. The combination of the two achieves chromatic aberration correction. The large difference in dispersion coefficients between fused silica and calcium fluoride materials can effectively correct axial chromatic aberration and magnification chromatic aberration.

[0029] This implementation significantly improves the transmittance in the ultraviolet band through the combination of fused silica and calcium fluoride materials; the combination of negative and positive optical power effectively corrects chromatic aberration, improving image clarity and color reproduction; and the double concave and double convex spherical design facilitates processing and assembly, reducing manufacturing costs.

[0030] As an example, an unreasonable lens configuration of the moving lens group 14 in an existing ultraviolet macro lens can lead to technical problems such as large changes in image quality and significant image shift during focusing. It is necessary to optimize the lens power and materials of the moving lens group 14.

[0031] Specifically, the third lens 141 is a positive power crescent-shaped lens made of fused silica; the fourth lens 142 is a negative power biconcave spherical lens made of calcium fluoride; and the fifth lens 143 is a positive power biconvex spherical lens made of fused silica. The object-side surface of the third lens 141 is a convex spherical surface with a radius of curvature of 32 mm, and the image-side surface is a concave spherical surface with a radius of curvature of 38 mm and a center thickness of 3.2 mm. Its crescent shape is beneficial for correcting astigmatism and field curvature. The two surfaces of the fourth lens 142 are both concave spherical surfaces with radii of curvature of -35 mm and -40 mm, respectively, and a center thickness of 2.5 mm. Its negative power is used to correct the total optical power of the system. The two surfaces of the fifth lens 143 are both convex spherical surfaces with radii of curvature of 28 mm and 30 mm, respectively, and a center thickness of 3.0 mm. It is used for final image focusing. The three lenses are separated by a metal spacer and are mounted as a whole on a movable lens mount, moving synchronously with the focusing ring 12. In practical applications, other models of this component can also be selected, and this application embodiment does not limit this.

[0032] When the movable lens group 14 moves along the optical axis, the third lens 141, the fourth lens 142 and the fifth lens 143 maintain their relative positions and change their distance from the fixed lens group 13 together; the positive and negative optical power configuration achieves optical power balance and reduces image quality fluctuations during focusing; the alternating use of fused silica and calcium fluoride materials further optimizes the chromatic aberration correction effect.

[0033] This implementation ensures that the moving lens group 14 maintains stable optical performance during focusing, and the image displacement is controlled within the allowable range; the three-element moving lens group design provides sufficient focusing freedom and a wide focal length adjustment range; the alternating material configuration further improves the imaging quality in the ultraviolet band.

[0034] As an example, the lack of a dedicated antireflection coating on the lens surface in existing ultraviolet macro lenses leads to technical problems such as low transmittance and large reflection loss in the ultraviolet band. It is necessary to optimize the wavelength range and transmittance of the ultraviolet antireflection coating.

[0035] The ultraviolet (UV) antireflection coating has a wavelength range of 300nm-400nm, with a transmittance of ≥85% within this range. The UV antireflection coating employs a multilayer dielectric film structure, consisting of alternating layers of materials such as silicon dioxide, magnesium fluoride, and aluminum oxide, with a total of 7-11 layers. The thickness of each layer is precisely controlled according to the principle of optical interference. The coating process utilizes ion beam assisted deposition technology, resulting in strong film adhesion and good environmental resistance. The antireflection coating covers all optical surfaces from the first lens 131 to the fifth lens 143, totaling 10 coated surfaces. At a center wavelength of 350nm, the single-sided reflectance is ≤1.5%, and the UV transmittance of the entire lens system can reach over 75%. In practical applications, other models of this component can also be selected; this application does not limit this.

[0036] The UV antireflection film utilizes the principle of light interference to cancel out reflected light and enhance transmitted light; the multilayer film structure design can achieve low reflectivity over a wide wavelength range; the 300nm-400nm wavelength range covers the UVA and UVB bands, meeting the needs of most UV detection applications.

[0037] This implementation significantly improves the light transmittance in the ultraviolet band and reduces light energy loss; the high transmittance improves the imaging signal-to-noise ratio, which is beneficial for the detection of weak ultraviolet signals; the wide wavelength range design enhances the versatility of the lens and can adapt to different ultraviolet light sources.

[0038] As an example, the insufficient precision of the focusing mechanism in existing ultraviolet macro lenses can lead to technical problems such as inaccurate focus adjustment and poor repeatability. Therefore, it is necessary to optimize the connection method and movement range of the focusing ring 12.

[0039] The focusing ring 12 and lens mount 11 are connected by a thread, with a focusing accuracy of 0.01mm. The moving lens group 14 has a movement range of 5-10mm, allowing the focal length to be adjusted between 20-35mm. The threaded connection uses a fine thread with a nominal diameter of 20mm and a pitch of 0.5mm, with a thread fit accuracy of 6H / 6g. One rotation of the focusing ring 12 moves the moving lens group 14 0.5mm along the optical axis, allowing for fine-tuning accuracy of 0.01mm via a dial. The movement range of the moving lens group 14 is controlled by a limiting structure, with a minimum movement distance of 5mm and a maximum movement distance of 10mm. The focal length adjustment range is 20mm to 35mm, covering close-up, macro, and mid-range shooting needs. The outer ring of the focusing ring 12 has focal length markings for easy user positioning of the desired focal length. In practical applications, other models of this component can also be selected; this embodiment does not limit this.

[0040] The threaded connection converts the rotational motion of the focusing ring 12 into the linear motion of the moving lens group 14; the fine thread design improves transmission accuracy and self-locking performance; the limiting structure prevents the moving lens group 14 from exceeding the allowable range and protects the optical system.

[0041] This implementation achieves high-precision focal length adjustment with a focusing accuracy of 0.01mm, meeting the requirements of precision testing; the 5-10mm movement range provides ample focusing travel to adapt to different object distances; and the 20-35mm focal length range covers common macro shooting scenarios, offering strong application flexibility.

[0042] As an example, the insufficient precision of the threaded connection between the focusing ring 12 and the lens mount 11 in existing ultraviolet macro lenses can lead to technical problems such as poor focusing feel and inaccurate positioning. Further optimization of the thread type and movement range is needed.

[0043] The focusing ring 12 and the lens mount 11 are connected by a fine-pitch thread, and the moving lens group 14 has a movement range of 8mm. The fine-pitch thread has a pitch of 0.35mm, which is smaller than that of ordinary threads, resulting in a shorter movement distance per turn and more precise focusing. The thread profile angle is 60 degrees, and the crest and root of the thread are chamfered to reduce frictional resistance. The 8mm movement range of the moving lens group 14 is precisely limited by front and rear limiting rings made of brass with a nickel-plated surface. The 8mm movement range corresponds to a focal length adjustment range of approximately 25-32mm, which is the optimal focal length range for commonly used macro photography. In practical applications, other models of this component can also be selected, and this embodiment does not limit this.

[0044] Fine-threaded connections improve focusing resolution and reduce lens movement distance when rotating by the same angle; the 8mm movement range is the result of optical design optimization, which controls the overall length of the lens while ensuring the focusing range.

[0045] This implementation further improves focusing accuracy and feel; the fine thread makes focusing smoother and more delicate; the 8mm movement range is the optimal balance point, which meets focusing requirements while avoiding excessive structural length; the limit ring design ensures the consistency of the movement range and improves product reliability.

[0046] As an example, the lack of clarity in the optical performance parameters of existing ultraviolet macro lenses can lead to technical problems such as unstable image quality and inability to guarantee detection accuracy. It is necessary to clearly define the key optical performance parameters of the lens.

[0047] The adjustable-focus ultraviolet macro lens 10 has a numerical aperture of 0.4-0.5, distortion ≤0.1%, and resolution ≥100 line pairs / mm. The numerical aperture of 0.4-0.5 is achieved through the rational design of the lens curvature radius and spacing, which determines the lens's light-gathering ability and depth of field. Distortion ≤0.1% is achieved through optimized lens group power distribution and aspherical design, ensuring minimal geometric distortion of the image. The resolution ≥100 line pairs / mm is ensured through high-quality optical design and precision manufacturing, with a minimum resolvable feature size of approximately 5 micrometers. The numerical aperture, distortion, and resolution are determined through optical design software optimization and verified during the sample stage using equipment such as interferometers and resolution test charts. In practical applications, other models of this component can also be selected; this application embodiment does not limit this.

[0048] Numerical aperture determines a lens's light-gathering ability and theoretical resolution; a numerical aperture of 0.4-0.5 is considered high among macro lenses. Low distortion ensures measurement accuracy, making it suitable for dimensional inspection applications. High resolution ensures that microscopic details can be clearly presented.

[0049] This implementation ensures high imaging quality of the adjustable-focus ultraviolet macro lens 10. The numerical aperture of 0.4-0.5 provides good light-gathering ability and moderate depth of field; the distortion ≤0.1% meets the requirements of geometric accuracy for precision measurement; and the resolution ≥100 line pairs / mm can clearly distinguish micron-level features, making it suitable for high-precision scenarios such as semiconductor defect detection.

[0050] As an example, the lack of light adjustment function in existing ultraviolet macro lenses can lead to technical problems such as inconsistent image brightness in different detection scenarios, requiring the addition of an aperture stop 16 to adjust the amount of light entering the lens.

[0051] Specifically, the adjustable-focus ultraviolet macro lens 10 of this application also includes an aperture stop 16, which is disposed between the fixed lens group 13 and the movable lens group 14. The aperture stop 16 adopts a multi-blade adjustable aperture stop structure with 5-7 blades. The blades are made of thin steel sheets with a blackened surface treatment to reduce stray light. The aperture opening diameter can be continuously adjusted within the range of 2mm-5mm. The aperture stop is installed in the air gap after the second lens 132 of the fixed lens group 13 and before the third lens 141 of the movable lens group 14. The aperture adjustment ring is disposed outside the lens mount 11 and is connected to the internal aperture blades through a linkage mechanism. Rotating the adjustment ring can change the size of the aperture opening. In practical applications, other models of this component can also be selected, and this embodiment of the application does not limit this.

[0052] The aperture stop 16 is located in the middle of the optical system and serves as the entrance and exit pupil of the system. Adjusting the size of the aperture stop can change the amount of light entering the lens, and at the same time affect the depth of field and diffraction effect. The aperture stop position is selected as close as possible to the ideal position of the system aperture stop 16 while ensuring space for the focusing mechanism.

[0053] This implementation provides an adjustable light intake function to adapt to the detection needs under different lighting conditions; the adjustable aperture design is highly flexible, allowing users to optimize the imaging effect according to actual conditions; the aperture position is reasonably designed to minimize the impact on optical performance.

[0054] As an example, the unoptimized aperture parameters of aperture stop 16 in existing ultraviolet macro lenses can lead to technical problems such as an inappropriate range of light intake adjustment, so it is necessary to limit the specific aperture of aperture stop 16.

[0055] The aperture stop 16 has a diameter of 3mm and is used to adjust the amount of light entering the camera. The 3mm aperture is the result of optimized optical design; in systems with a numerical aperture of 0.4-0.5, a 3mm aperture provides a moderate amount of light. An aperture that is too small will result in significant diffraction, reducing resolution; an aperture that is too large will result in a shallow depth of field, which is detrimental to macro photography. The 3mm aperture achieves the best balance between light intake, resolution, and depth of field. The aperture stop 16 is precision-machined, with tolerances controlled within ±0.05mm. In practical applications, other models of this component can also be selected; this embodiment does not limit the choice.

[0056] The 3mm aperture determines the effective light transmission diameter of the system, affecting image brightness and depth of field; in the ultraviolet band, the 3mm aperture can reduce stray light and ghosting; the aperture size is matched with the optical power of the lens group to ensure the overall performance of the optical system.

[0057] This implementation method, with its 3mm aperture design, controls aberrations while ensuring sufficient light intake; the moderate aperture provides a reasonable depth of field range, facilitating focusing in macro photography; and the aperture precision control ensures product consistency and improves the quality stability of mass production.

[0058] As an example, the lack of clear application scenarios in existing ultraviolet macro lenses can lead to technical problems such as unclear product positioning and difficulties in market promotion. It is necessary to clarify the applicable scenarios of the lenses.

[0059] The adjustable-focus ultraviolet macro lens 10 provided in this application is suitable for semiconductor micro-defect detection, ultraviolet imaging of micro-parts, or observation of biological microstructures. In semiconductor micro-defect detection, the lens is used to detect defects such as scratches, particles, and cracks on the wafer surface, requiring high detection accuracy; the ultraviolet band can enhance defect contrast. In micro-part ultraviolet imaging, the lens is used to photograph the surface morphology of tiny objects such as precision mechanical parts and electronic components; ultraviolet light can reveal surface features invisible under visible light. In biological microstructure observation, the lens is used to observe the microstructure of biological samples such as cells and tissue sections; ultraviolet fluorescence imaging can provide specific labeling information. All three scenarios require the lens to have high numerical aperture, low distortion, and high resolution optical performance. In practical applications, other models of this component can also be selected; this application embodiment does not limit this.

[0060] In semiconductor inspection, ultraviolet light is used to improve the detection rate by utilizing its high sensitivity to defects; in micro-part imaging, ultraviolet light is used to enhance the surface morphology and reveal subtle features; and in biological observation, ultraviolet fluorescence is used to achieve specific labeling and imaging.

[0061] This implementation method clearly defines the target market and application areas of the product, which is conducive to product positioning and market promotion; the three scenarios cover the main needs of industrial testing and scientific research observation, and have great market potential; the scenario descriptions match the lens performance parameters, reflecting the product's technical advantages and application value.

[0062] As an example, the lack of clear optical parameters for lens materials in existing ultraviolet macro lenses can lead to technical problems such as arbitrary material selection and unstable performance. Therefore, it is necessary to clearly define the refractive index and dispersion coefficient of the first lens 131 and the second lens 132.

[0063] The first lens 131 has a refractive index Nd = 1.46 and a dispersion coefficient Vd = 67.8; the second lens 132 has a refractive index Nd = 1.43 and a dispersion coefficient Vd = 95. The first lens 131 is made of fused silica, with a refractive index of 1.46 that remains stable in the ultraviolet band and a dispersion coefficient of 67.8, which is considered moderate dispersion and beneficial for chromatic aberration correction. The second lens 132 is made of calcium fluoride, with a refractive index of 1.43 slightly lower than fused silica and a dispersion coefficient of 95, which is considered low dispersion. Combined with fused silica, it achieves good achromatic aberration effects. The difference in refractive index between the two materials is 0.03, and the difference in dispersion coefficient is 27.2, a moderate parameter difference that ensures achromatic aberration effects while avoiding material stress problems. The material parameters are confirmed through supplier testing reports, with batch-to-batch fluctuations controlled within ±0.01. In practical applications, other models of this component can also be selected; this application embodiment does not limit this.

[0064] Refractive index and dispersion coefficient are core parameters of optical materials, determining the optical power and chromatic aberration characteristics of lenses. Reasonable differences in the parameters of the two materials form an effective achromatic combination. Parameter constraints ensure the consistency of material selection and improve the stability of product performance.

[0065] This implementation method ensures consistent lens performance by clearly defining the optical parameters of the materials; the parameter combination of fused silica and calcium fluoride achieves excellent achromatic effect; the parameter limitation facilitates material procurement and quality control, and improves the feasibility of mass production.

[0066] As an example, the lack of clear parameters for each lens in the moving lens group 14 of an existing ultraviolet macro lens can lead to technical problems such as uncontrollable processing accuracy and assembly difficulties. It is necessary to clearly define the focal length and center thickness of the third lens 141, the fourth lens 142, and the fifth lens 143.

[0067] The third lens 141 has a focal length of 35mm and a center thickness of 3.2mm; the fourth lens 142 has a focal length of -42mm and a center thickness of 2.5mm; and the fifth lens 143 has a focal length of 30mm and a center thickness of 3.0mm. The third lens 141, with a focal length of 35mm and positive optical power, and a center thickness of 3.2mm, ensures sufficient mechanical strength while controlling lens weight. The fourth lens 142, with a focal length of -42mm and negative optical power, has a relatively thin center thickness of 2.5mm, which helps reduce the overall weight of the moving lens group. The fifth lens 143, with a focal length of 30mm and positive optical power, has a center thickness of 3.0mm, similar to the third lens 141, maintaining structural symmetry. The focal length combination of the three lenses (35mm, -42mm, 30mm) forms a positive-negative-positive optical power distribution, with a total optical power of approximately +23mm. The center thickness tolerance is controlled within ±0.02mm, and the focal length tolerance is controlled within ±1%. In practical applications, other models of this component can also be selected, and this application embodiment does not limit this.

[0068] The focal length and thickness parameters of the three lenses were determined through optical design optimization to ensure the optical performance of the moving lens group 14; the positive and negative optical power distribution achieved optical power balance and reduced image quality changes during focusing; the center thickness parameter took into account processing feasibility and mechanical strength requirements.

[0069] This implementation method ensures the feasibility of optical performance by specifying the parameters of each lens in the movable lens group 14; the focal length and thickness parameters are reasonable, taking into account both optical and mechanical performance; the parameter limitation facilitates processing inspection and quality control, thereby improving product consistency and reliability.

[0070] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An adjustable-focus ultraviolet macro lens, characterized in that, The system includes a lens mount (11), a focusing ring (12), a fixed lens group (13), a movable lens group (14), and an imaging sensor (15). The fixed lens group (13) and the movable lens group (14) are arranged sequentially from the object side to the image side along the optical axis within the lens mount (11). The focusing ring (12) is connected to the movable lens group (14) and is used to adjust the movable lens group (14) to move along the optical axis to achieve focal length adjustment. The fixed lens group (13) includes a first lens (131) and a second lens (132) arranged sequentially from the object side to the image side; The movable lens group (14) includes a third lens (141), a fourth lens (142) and a fifth lens (143) arranged sequentially from the object side to the image side. The surfaces of the first lens (131) to the fifth lens (143) are all coated with an ultraviolet anti-reflection film.

2. The adjustable-focus ultraviolet macro lens according to claim 1, characterized in that, The first lens (131) is a negative optical power biconcave spherical lens made of fused silica material; The second lens (132) is a biconvex spherical lens with positive optical power and is made of calcium fluoride material.

3. The adjustable-focus ultraviolet macro lens according to claim 1, characterized in that, The third lens (141) is a positive optical power crescent moon lens, made of fused silica material; The fourth lens (142) is a negative optical power biconcave spherical lens made of calcium fluoride material; The fifth lens (143) is a positive optical power biconvex spherical lens made of fused silica material.

4. The adjustable-focus ultraviolet macro lens according to claim 1, characterized in that, The ultraviolet antireflective film has a wavelength range of 300nm-400nm and a transmittance of ≥85% within the wavelength range.

5. The adjustable-focus ultraviolet macro lens according to claim 1, characterized in that, The focusing ring (12) and the lens mount (11) are connected by a thread, the focusing accuracy is 0.01mm, and the moving lens group (14) has a moving range of 5-10mm, so that the focal length can be adjusted between 20-35mm. Preferably, the focusing ring (12) and the lens mount (11) are connected by a fine thread, and the moving lens group (14) has a moving range of 8 mm.

6. The adjustable-focus ultraviolet macro lens according to claim 1, characterized in that, The adjustable-focus ultraviolet macro lens (10) has a numerical aperture of 0.4-0.5, distortion ≤0.1%, and resolution ≥100 line pairs / mm.

7. The adjustable-focus ultraviolet macro lens according to claim 1, characterized in that, It also includes an aperture stop (16), which is disposed between the fixed lens group (13) and the movable lens group (14); Preferably, the aperture of the aperture stop (16) is 3 mm, which is used to adjust the amount of light entering the aperture.

8. The adjustable-focus ultraviolet macro lens according to any one of claims 1 to 7, characterized in that, The adjustable focus ultraviolet macro lens (10) is suitable for semiconductor micro-defect detection, ultraviolet imaging of micro-parts, or observation of biological microstructures.

9. The adjustable-focus ultraviolet macro lens according to claim 2 or 3, characterized in that, The first lens (131) has a refractive index of Nd=1.46 and a dispersion coefficient of Vd=67.8; The second lens (132) has a refractive index of Nd=1.43 and a dispersion coefficient of Vd=95.

10. The adjustable-focus ultraviolet macro lens according to claim 3, characterized in that, The third lens (141) has a focal length of 35mm and a center thickness of 3.2mm; The fourth lens (142) has a focal length of -42mm and a center thickness of 2.5mm; The fifth lens (143) has a focal length of 30 mm and a center thickness of 3.0 mm.

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