An electric mechanism for adjusting the air layer of an illumination objective

Abstract

The utility model discloses a kind of electric mechanism for adjusting air layer of lighting objective, including lens barrel, moving group component, linear drive unit etc.;Fixed lens group is located in lens barrel, including front group component, middle three group components and rear group component etc.;Moving group component is located between middle three group components and rear group component, including moving group lens seat and lens five fixed thereon;Linear drive unit includes linear module;Transmission peg one end is connected with moving group lens seat, the other end passes through first slot hole on lens barrel, second slot hole on transmission seat;Elastic pre-tightening unit is located between moving group component and fixed lens group, so that transmission peg is always close to the inner wall of second slot hole side;Linear module drives transmission seat to move along the direction parallel to optical axis, moving group component is driven in lens barrel by transmission peg synchronous movement, to change the air layer thickness between it and adjacent lens group, realize focusing.The utility model solves the problem of low positioning accuracy and poor repeatability caused by large transmission gap in the prior art.

Description

Technical Field

[0001] This utility model relates to the field of optical imaging and lighting equipment technology, and more specifically, to an electric drive mechanism for adjusting the thickness of the air layer in an illumination objective lens to achieve precise focusing. Background Technology

[0002] In optical illumination and imaging systems, precise adjustment of the optical focus is often required to achieve clear observation or uniform illumination. Traditional adjustment methods are mainly divided into two categories: manual and electric.

[0003] 1. Manual adjustment mechanism and its limitations:

[0004] As the most traditional method, it relies on rotating threads to drive the lens barrel or mount to move back and forth. Although the structure is simple and the cost is low, its adjustment accuracy depends entirely on the operator's experience and feel, making it impossible to achieve automation and digital control. The more fundamental drawback is that the threaded pair inherently has a clearance, and after long-term reciprocating use, it will inevitably wear down, leading to serious return errors and deterioration of positioning repeatability, which completely fails to meet the requirements of modern precision equipment for long-term stability and repeatable positioning.

[0005] 2. Common forms and problems of electric adjustment mechanisms:

[0006] To achieve electrification and programmability, stepper or servo motors are used in conjunction with lead screw drives. While these offer advantages in terms of stroke and driving force, the inherent backlash in the drive chain becomes a bottleneck for improving accuracy. Furthermore, the longer drive chain reduces system rigidity, easily introducing vibration and noise. Additionally, the lead screw may experience significant temperature rise or "creeping" phenomena at high or low speeds, affecting the smoothness and accuracy stability of the motion.

[0007] Therefore, in the specific application scenario of air layer adjustment for illumination lenses, the market urgently needs a new type of electric mechanism that must be able to: achieve nanometer-level positioning accuracy and extremely high repeatability while ensuring sufficient stroke and driving force; fundamentally eliminate transmission backlash to ensure positional certainty in the direction of movement; possess excellent guiding accuracy to control lens eccentricity and tilt; and simultaneously be compact, highly rigid, operate smoothly and quietly, and adaptable to certain industrial environmental fluctuations. This utility model is a systematic solution proposed to address this series of intertwined technical challenges. Summary of the Invention

[0008] The technical problem to be solved by this utility model is to provide an electric mechanism for adjusting the air layer of an illumination objective lens, which addresses the shortcomings of the prior art. This electric mechanism for adjusting the air layer of an illumination objective lens solves the technical problems of low positioning accuracy and poor repeatability caused by large transmission gaps in the prior art.

[0009] To achieve the above-mentioned technical objectives, the technical solution adopted by this utility model is as follows:

[0010] An electric mechanism for adjusting the air layer of an illumination objective lens includes: a lens barrel having an inner hole extending along the optical axis, a fixed lens assembly, a movable moving assembly, a linear drive unit, a transmission pin, and an elastic preload unit.

[0011] The fixed lens assembly is disposed inside the lens barrel and includes a front group component, a middle group component, a middle second group component, a middle third group component, and a rear group component arranged sequentially from front to back along the optical axis;

[0012] The moving assembly is located between the middle three assemblies and the rear assembly, and includes a moving assembly lens mount and a lens five fixed thereon;

[0013] The linear drive unit is fixed to the outside of the lens barrel and includes a linear module, a transition plate and a transmission seat. The mover of the linear module is rigidly connected to the transmission seat through the transition plate.

[0014] One end of the transmission pin is fixedly connected to the moving lens mount, and the other end passes through the first slot on the side wall of the lens barrel and the second slot on the transmission base.

[0015] The elastic preload unit is disposed between the moving assembly and the fixed mirror assembly, and is used to apply a continuous axial preload to the moving assembly, so that the transmission pin is always in close contact with the inner wall of one side of the second slot.

[0016] The linear module is used to drive the transmission base to move in a direction parallel to the optical axis, and drives the moving parts to move synchronously inside the lens barrel through the transmission pin, so as to change the air layer thickness between it and the adjacent lens group and realize focusing.

[0017] As a further improvement of the present invention, the inner hole of the lens barrel and the outer circle of the moving lens mount are in a precision sliding fit, and the fit clearance is controlled within the range of 0 to 0.01 mm. Furthermore, the tilt angle of the outer circle axis of the moving lens mount relative to the inner hole axis of the lens barrel is controlled within 30 arcseconds.

[0018] As a further improvement of the present invention, the elastic preload unit includes an aperture and a compression spring; the aperture is formed by a fixed connection of an external thread section and a rod section, the external thread section being screwed into the corresponding internal thread of the middle three-group component; the compression spring is sleeved on the outer periphery of the rod section of the aperture extending out of the middle three-group component; one end of the compression spring abuts against the flange of the aperture or the end face of the middle three-group component, and the other end abuts against the end face of the moving lens mount, providing a preload force to the moving lens mount in a direction away from the middle three-group component; one end of the rod section of the aperture extends into the inner hole of one end of the moving lens mount, and there is a gap between the outer wall of the rod section and the inner wall of the inner hole of the moving lens mount.

[0019] As a further improvement of this utility model, the spring preload force F2 provided by the elastic preload unit is always greater than the reverse load force F1 applied to the transmission seat by the linear drive unit throughout the entire stroke of the moving assembly.

[0020] As a further improvement of this utility model, the moving assembly lens mount and the lens five in the moving assembly component are bonded and fixed by low-stress adhesive, and the optical axis of the lens five is made to coincide with the mechanical axis of the outer circle of the moving assembly lens mount by the image repair process.

[0021] As a further improvement of this utility model, in the fixed lens assembly, the front lens mount and lens one in the front group are bonded and fixed with low-stress adhesive, and the optical axis of lens one is made to coincide with the mechanical axis of the outer circle of the front lens mount through an image retouching process; in the middle group, the middle lens mount and lens two are bonded and fixed with low-stress adhesive, and the optical axis of lens two is made to coincide with the mechanical axis of the outer circle of the middle group lens mount through an image retouching process; in the middle group, the middle group two lens mount and lens three are bonded and fixed with low-stress adhesive, and the optical axis of lens three is made to coincide with the mechanical axis of the outer circle of the middle group lens mount through an image retouching process; in the middle group, the middle group three lens mount and lens four are bonded and fixed with low-stress adhesive, and the optical axis of lens four is made to coincide with the mechanical axis of the outer circle of the middle group lens mount through an image retouching process; in the rear group, the rear lens mount and lens six are bonded and fixed with low-stress adhesive, and the optical axis of lens six is ​​made to coincide with the mechanical axis of the outer circle of the rear lens mount through an image retouching process.

[0022] The middle three-group component, the middle two-group component, the middle one-group component, and the front group component are sequentially inserted into the lens barrel from the front end. The front pressure ring is screwed into the front end of the lens barrel through a thread, thereby pressing the front group component, the middle one-group component, the middle two-group component, and the middle three-group component as a whole onto the pre-designed axial step inside the lens barrel. The outer circular wall of the front group lens mount, the middle one-group lens mount, the middle two-group lens mount, and the middle three-group lens mount is fitted with a small clearance to the inner wall of the front end of the lens barrel.

[0023] The rear assembly is inserted into the lens barrel from the rear end, and the rear pressure ring is screwed into the rear end of the lens barrel through a thread to press the rear lens mount end face of the rear assembly onto the pre-designed axial step inside the lens barrel; the outer circular wall of the rear lens mount is fitted with a small clearance to the inner wall of the rear end of the lens barrel.

[0024] As a further improvement of this utility model, both the lens barrel and the moving lens mount are made of 304 stainless steel.

[0025] As a further improvement of the present invention, the technical solution also includes a linear module support base, a sealing plate and a cover plate. The linear module support base is used to install and support the linear module. The linear module support base is fixed to the outside of the lens barrel by fasteners. The linear module, the transition plate and the transmission seat are all located inside the linear module support base. The linear module support base has two openings, which are respectively aligned with the positions of the transmission pins. The openings are covered by the cover plate.

[0026] As a further improvement of the present invention, the transmission pin is formed by connecting a rod body and a threaded end. The threaded end is threadedly connected to a reserved threaded hole on the moving lens mount. The end face of the rod body connected to the threaded end is tightly fitted with the outer end face of the reserved threaded hole on the moving lens mount. The second slot on the transmission seat is a waist-shaped hole that can accommodate one end of the transmission pin.

[0027] As a further improvement of this utility model, there are two transmission pins, two reserved threaded holes on the moving lens mount, and two second slots on the transmission seat; the first slot on the side wall of the lens barrel is an elongated hole, and there are two of them.

[0028] The beneficial effects of this utility model are as follows:

[0029] 1. This utility model abandons the piezoelectric ceramic or voice coil motor with extremely short stroke and adopts a high-precision linear module as the core drive source. The linear module itself has nanometer-level resolution and positioning capability, and the stroke can be selected to meet the adjustment range as needed, perfectly adapting to the requirements of air layer thickness adjustment, and realizing ultra-high precision positioning under long stroke.

[0030] 2. This utility model, through a combination of "high-precision mechanical guidance" and "elastic pre-tightening backlash elimination," ensures that the mechanism's movement does not rely on easily worn threaded pairs or lead screw pairs with backlash. The precise fit between the moving assembly mirror mount and the mirror barrel provides a permanent physical guiding reference, and the spring backlash elimination mechanism ensures the positional certainty of each movement. Therefore, the mechanism maintains extremely high repeatability and positioning accuracy, with no backlash error, and its performance does not degrade over time during long-term, frequent reciprocating motion.

[0031] In summary, points 1 and 2 completely resolve the contradiction between "precision and stability," achieving a balance between high precision and high stability. This solves the problems of short stroke and poor stability in traditional high-precision direct-drive mechanisms (such as piezoelectric ceramics) and the difficulty in achieving nanometer-level micro-motion precision in high-stability transmission mechanisms (such as lead screws).

[0032] 3. Fundamental Elimination of Transmission Backlash: This invention creatively introduces a unidirectional constant force elastic preload mechanism. By precisely matching the spring force and the load force, it ensures that the transmission pin and the transmission seat are in a "surface contact" force-locked state at any moment of movement, thus eliminating the backlash in the transmission chain from a physical principle and realizing a true one-to-one mapping of "electrical command - mechanical position".

[0033] 4. Constructing a short, high-rigidity transmission chain: The entire transmission path is "linear module → transition plate → transmission seat → transmission pin → moving assembly components," with an extremely short transmission chain and all connections being rigid. The main load-bearing structures (lens barrel, lens mount) are made of high-strength stainless steel, and the overall system rigidity is far higher than that of a direct-drive mechanism, capable of withstanding greater loads and inertial forces. While ensuring backlash-free movement, it possesses excellent rigidity and dynamic performance.

[0034] In summary, points 3 and 4 fundamentally resolve the contradiction between "rigid transmission and backlash-free motion," achieving backlash-free transmission under high rigidity. This solves the technical problems of backlash in rigid mechanical transmissions (such as lead screws) and the potential for insufficient rigidity and load capacity in direct drive solutions that pursue backlash-free operation.

[0035] 5. Excellent temperature stability: Key moving parts (lens barrel and moving mount) are made of the same stainless steel material with the same coefficient of thermal expansion, effectively reducing the drift in fitting accuracy caused by temperature changes. The all-metal structure has good thermal conductivity and uniform heat distribution, and its temperature adaptability is far superior to that of piezoelectric ceramics and other mechanisms that are sensitive to temperature drift.

[0036] 6. Excellent dustproof and vibration-resistant capabilities: The moving parts (moving lens mount) are sealed inside the lens barrel, and the openings on the linear module support are protected by covers, greatly reducing the risk of dust intrusion leading to jamming or wear. The compact, high-rigidity overall structure effectively suppresses and withstands minor vibrations in the working environment, maintaining stable focusing.

[0037] 7. Low noise and low maintenance operation: Utilizing a precision sliding fit between metal parts, the friction characteristics are stable, avoiding audible noise from gear and lead screw meshing. The structure is simple and reliable, with no easily damaged transmission components, resulting in quiet operation and virtually no maintenance required, reducing operating costs and interference with the working environment.

[0038] In summary, points 5-7 systematically overcome the environmental sensitivity of existing mechanisms, achieving excellent overall performance and environmental robustness. This solves the technical problems of high-precision mechanisms being sensitive to environmental factors (temperature, dust, vibration) and the high cost of improving environmental adaptability.

[0039] In summary, this invention successfully breaks through the traditional trade-offs between "precision-stability," "rigidity-backlash-free performance," and "performance-environmental adaptability" in existing technologies by organically integrating a high-precision guiding structure, a spring pre-tensioning backlash-eliminating principle, an all-metal rigid integrated design, and a high-grade linear module. Its core beneficial effects can be summarized as follows: in the application of air layer adjustment for illumination objectives, it achieves a high degree of unity between nanometer-level precision, ultra-high repeatability with zero backlash, extremely high operational stability, excellent environmental robustness, and silent operation, providing a revolutionary and reliable solution for focusing systems in high-end precision optical equipment. Attached Figure Description

[0040] Figure 1 This is an isometric view of an electric mechanism for adjusting the air layer of an illumination objective lens.

[0041] Figure 2 This is a front view of an electric mechanism for adjusting the air layer of an illumination objective.

[0042] Figure 3 for Figure 2 Sectional view of AA.

[0043] Figure 4 for Figure 2 Cross-sectional view of the middle section (BB).

[0044] Figure 5 This is an isometric view of the transmission seat.

[0045] Figure 6 This is an axonometric view of the microscope tube.

[0046] Figure 7 This is an axonometric view of the moving lens mount.

[0047] Figure 8 This is a schematic diagram showing the relative positions of the transmission base and the moving assembly mirror base after they are connected by a transmission pin.

[0048] Figure 9 This is an isometric view of the linear module.

[0049] Figure 10 This is a diagram illustrating the working state of an electric mechanism for adjusting the air layer in an illumination objective lens.

[0050] Figure 11 This is an optical system diagram of the illumination objective.

[0051] The parts shown in the diagram include: 1. Lens barrel; 2. Front pressure ring; 3. Cover plate; 4. Front lens mount; 5. Middle lens mount; 6. Middle lens mount; 7. Middle lens mount; 8. Aperture; 9. Spring; 10. Transmission base; 20. Lens 3; 21. Moving lens mount; 22. Rear lens mount; 23. Rear pressure ring; 24. Transition plate; 25. Linear module; 26. Linear module support; 27. Sealing plate; 28. Lens 1; 29. ​​Lens 2; 31. Lens 4; 32. Lens 5; 33. Transmission pin; 34. Lens 6; 101. First slot; 1001. Second slot; 2101. Reserved threaded hole; 2501. Mover; 2502. Stator; A. Surface of the illumination objective lens; B. Mask surface. Detailed Implementation

[0052] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings:

[0053] like Figure 1 As shown, an electric mechanism for adjusting the air layer of an illumination objective lens includes: a lens barrel 1 having an inner hole extending along the optical axis, a fixed lens assembly, a movable moving assembly, a linear drive unit, a transmission pin 33, and an elastic preload unit.

[0054] The fixed lens assembly is disposed inside the lens barrel 1 and includes a front group component, a middle group component, a middle second group component, a middle third group component, and a rear group component arranged sequentially from front to back along the optical axis.

[0055] like Figure 2-4 As shown, the front lens mount 4 and lens 1 28 are glued together as a single unit using low-stress adhesive, collectively referred to as the front group component. The middle lens mount 5 and lens 2 29 are glued together as a single unit using low-stress adhesive, collectively referred to as the middle group component. The middle lens mount 6 and lens 3 20 are glued together as a single unit using low-stress adhesive, collectively referred to as the middle group component. The middle lens mount 7 and lens 4 31 are glued together as a single unit using low-stress adhesive, collectively referred to as the middle group component. The rear lens mount 22 and lens 6 34 are glued together as a single unit using low-stress adhesive, collectively referred to as the rear group component.

[0056] The moving assembly is located between the middle three-group assembly and the rear assembly, and includes a moving lens mount 21 and a lens 32 fixed thereon. The moving lens mount 21 and the lens 32 are glued together as a whole with low-stress adhesive and are collectively referred to as the moving assembly.

[0057] like Figure 3 As shown, the linear drive unit is fixed outside the lens barrel 1 and includes a linear module 25, a transition plate 24 and a transmission seat 10. The mover 2501 of the linear module 25 is rigidly connected to the transmission seat 10 through the transition plate 24.

[0058] One end of the transmission pin 33 is connected to the reserved threaded hole 2101 in the moving assembly mirror mount 21 (e.g., ...). Figure 7 The other end is fixedly connected and passes through the first slot 101 provided on the side wall of the lens barrel 1 (e.g., Figure 6 ) and the second slot 1001 provided on the transmission seat 10 (such as Figure 5 The elastic preload unit is disposed between the moving assembly and the fixed mirror assembly, and is used to apply a continuous axial preload to the moving assembly, so that the transmission pin 33 is always in close contact with one side inner wall of the second slot 1001. Figure 8 This is a schematic diagram showing the relative positions of the transmission base 10 and the moving mirror base 21 after they are connected by the transmission pin 33.

[0059] The linear module 25 drives the transmission base 10 to move in a direction parallel to the optical axis. Through the transmission pin 33, it drives the moving assembly components to move synchronously within the lens barrel 1, thereby changing the air layer thickness between the moving assembly and adjacent lens assemblies to achieve focusing. The linear module 25 includes a stator and a mover, as well as a controller and related cables. The linear module 25 is an existing precision electric linear module capable of achieving nanometer-level positioning accuracy.

[0060] In this embodiment, the inner hole of the lens barrel 1 and the outer circle of the moving lens mount 21 are in a precision sliding fit, with the fit clearance controlled within the range of 0 to 0.01 mm. Furthermore, the tilt angle of the outer circle axis of the moving lens mount 21 relative to the inner hole axis of the lens barrel 1 is controlled within 30 arcseconds. Through machining, the eccentricity error between the inner hole of the lens barrel 1 and the outer circle of the moving lens mount 21 is ensured to be within 0.01 mm, and the tilt is controlled within 30″. Moreover, since the optical axis of lens 5 32 (the optical axis formed by the line connecting the centers of the two R-value spheres) is coaxial with the mechanical axis of the outer circle of the moving lens mount 21 in the moving assembly component, the eccentricity error of the lens is indirectly ensured to be controlled within 0.01 mm, and the lens tilt is controlled within 30″.

[0061] In this embodiment, as Figure 3 The elastic preload unit includes an aperture 8 and a compression spring 9. The aperture 8 is formed by a fixed connection of an external thread section and a rod section, with the external thread section screwed into the corresponding internal thread of the middle three-group component. The compression spring 9 is sleeved on the outer periphery of the rod section of the aperture 8 extending out of the middle three-group component. One end of the compression spring 9 abuts against the flange of the aperture 8 or the end face of the middle three-group component, and the other end abuts against the end face of the moving lens mount 21, providing a preload force to the moving lens mount in a direction away from the middle three-group component. One end of the rod section of the aperture 8 extends into the inner hole of one end of the moving lens mount 21, and there is a gap between the outer wall of the rod section and the inner wall of the inner hole of the moving lens mount 21.

[0062] In this embodiment, the spring preload force F2 provided by the elastic preload unit is always greater than the reverse load force F1 applied to the transmission seat 10 by the linear drive unit throughout the entire stroke of the moving assembly.

[0063] Given the load force F1 on the linear module 25, the spring force F2 (right limit 0.414N, left limit 0.643N) and the dynamic force F3 of the linear module are calculated. It is required that F2 > F1 be maintained at both the lower and upper limits of the moving module, which can be calculated. Maintaining F2 > F1 aims to eliminate the gap error between the transmission pin 33 and the second slot 1001 on the transmission seat 10, ensuring that the transmission pin 33 always adheres to one side of the inner wall of the second slot 1001, thus maintaining the positional consistency of the moving components. The optical axis of the moving components remains consistent with the optical axes of other components through the tolerance fit between the lens barrel and the lens mount, with the tolerance controlled within 0–0.01 mm. Under the action of the linear module 25, utilizing the nanometer-level precision of the linear module 25, the transition plate 24 and the transmission seat 10 move up and down (the mechanism of this utility model is configured to...). Figure 10 In the vertical working state shown, the linear module 25 drives the moving assembly to move up and down to adjust the focus. The transmission seat 10 pushes the transmission pin 33 up and down, and the transmission pin 33 is fixed on the moving assembly. In this way, the air layer in front of and behind the moving assembly is changed at the nanometer level, and finally the focusing is achieved. Figure 11 As shown, this specifically indicates the surface location of the mask, and the purpose of focusing the illumination objective lens onto this mask surface B.

[0064] In this embodiment, the moving assembly lens mount 21 and the lens 32 in the moving assembly component are bonded and fixed by low-stress adhesive, and the optical axis of the lens 32 is made to coincide with the mechanical axis of the outer circle of the moving assembly lens mount 21 by the image retouching process.

[0065] In this embodiment, the front lens mount 4 and lens 28 in the front group of the fixed lens assembly are bonded and fixed with low-stress adhesive, and the optical axis of lens 28 is aligned with the mechanical axis of the outer circle of the front lens mount 4 through an image retouching process; the middle lens mount 5 and lens 29 in the middle group are bonded and fixed with low-stress adhesive, and the optical axis of lens 29 is aligned with the mechanical axis of the outer circle of the middle lens mount 5 through an image retouching process; the middle lens mount 6 and lens 20 in the middle group are bonded with low-stress adhesive. The optical axis of lens 3 20 is fixed and aligned with the mechanical axis of the outer circle of the middle second group lens mount 6 through an image retouching process. In the middle third group component, the middle third group lens mount 7 and lens 4 31 are fixed together with low-stress adhesive and aligned with the mechanical axis of the outer circle of the middle third group lens mount 7 through an image retouching process. In the rear group component, the rear group lens mount 22 and lens 6 34 are fixed together with low-stress adhesive and aligned with the mechanical axis of the outer circle of the rear group lens mount 22 through an image retouching process.

[0066] The middle three-group component, the middle two-group component, the middle one-group component, and the front group component are sequentially inserted into the lens barrel 1 from the front end of the lens barrel 1, and the front pressure ring 2 is screwed into the front end of the lens barrel 1 by threads, thereby pressing the front group component, the middle one-group component, the middle two-group component, and the middle three-group component as a whole onto the pre-designed axial step inside the lens barrel 1; the outer circular wall of the front group lens mount 4, the middle one-group lens mount 5, the middle two-group lens mount 6, and the middle three-group lens mount 7 is fitted with a very small clearance to the inner wall of the front end of the lens barrel 1.

[0067] The rear assembly is inserted into the lens barrel 1 from the rear end of the lens barrel 1, and the rear pressure ring 23 is screwed into the rear end of the lens barrel 1 by threads, thereby pressing the end face of the rear lens mount 22 of the rear assembly onto the pre-designed axial step inside the lens barrel 1; the outer circular wall of the rear lens mount 22 is fitted with the inner wall of the rear end of the lens barrel 1 with a very small clearance.

[0068] In this embodiment, both the lens barrel 1 and the moving lens mount 21 are made of 304 stainless steel. The slight eccentricity and tilting errors between the inner hole of the lens barrel 1 and the outer circle of the moving lens mount 21 ensure high radial positioning accuracy and good stability. The low noise level is due to the fact that both the lens barrel 1 and the moving lens mount 21 are made of 304 stainless steel, which generates almost no noise.

[0069] In this embodiment, a linear module support base 26, a sealing plate 27, and a cover plate 3 are also included. The linear module support base 26 is used to install and support the linear module 25. The linear module support base 26 is fixed to the outside of the lens barrel 1 by fasteners. The linear module 25, the transition plate 24, and the transmission seat 10 are all located inside the linear module support base 26. The linear module support base 26 has two openings, which are aligned with the positions of the transmission pins 33. The openings are covered by the cover plate 3.

[0070] In this embodiment, the transmission pin 33 is formed by connecting a rod body and a threaded end. The threaded end is threadedly connected to the reserved threaded hole 2101 on the moving lens mount 21. The end face of the rod body connected to the threaded end is connected to the outer end face of the reserved threaded hole 2101 on the moving lens mount 21 (e.g., ...). Figure 7As shown, the outer end face of the pre-drilled threaded hole 2101 is machined to be horizontal to facilitate the machining of the threaded hole. The second slot 1001 on the transmission seat 10 is a waist-shaped hole that can accommodate one end of the transmission pin 33. The length direction of the waist-shaped hole is perpendicular to the axial direction. To facilitate the installation of the transmission pin 33, the width of the waist-shaped hole is slightly larger than the outer diameter of the transmission pin 33 in the axial direction. That is, there is a gap between the transmission pin 33 and the width direction of the waist-shaped hole. To eliminate this transmission gap, an elastic preload unit is provided. A continuous axial preload force is applied to the moving assembly component through the elastic preload unit, ensuring that the transmission pin 33 is always tightly pressed against one side of the inner wall of the second slot 1001. In other words, by precisely matching the spring force and the load force, it is ensured that the transmission pin 33 and the transmission seat 10 are in a "face contact" force-locked state at any moment of movement, eliminating the backlash in the transmission chain from a physical principle and realizing a true one-to-one mapping of "electrical command - mechanical position". In addition, the purpose of setting the waist-shaped hole with the length direction perpendicular to the axial direction (movement direction) is that, since this paper sets two transmission pins 33, which are respectively installed on the two reserved threaded holes 2101 on the moving lens mount 21, after the transmission pins 33 are screwed into the reserved threaded holes 2101, they may be tilted in the direction perpendicular to the movement direction. The waist-shaped hole provides sufficient installation space for the transmission pins 33, eliminating the jamming phenomenon caused by the tilting of the transmission pins 33.

[0071] In this embodiment, there are two transmission pins 33, two reserved threaded holes 2101 on the moving lens mount 21, and two second slots 1001 on the transmission seat 10; the first slots 101 on the side wall of the lens barrel 1 are elongated holes that make room for movement, and there are two of them.

[0072] The assembly steps in this embodiment are as follows:

[0073] 1. The transition plate 24 is fixed on the mover 2501 of the linear module 25, and the transmission seat 10 is fixed on the transition plate 25. The whole is embedded in the linear module support seat 26. The stator 2502 of the linear module 25 and the lower part of the linear module support seat 26 are fixed by screws to form a whole.

[0074] 2. The entire assembly is fixed to the lens barrel 1. The linear module support 26 is connected to the protruding structure on the periphery of the lens barrel 1 by screws. The moving assembly, including the moving lens mount 21 and the lens 5 32, passes through the inner hole on the left side of the lens barrel 1. The reserved threaded hole 2101 at the moving lens mount 21, the first slot 101 of the lens barrel 1, the second slot 1001 of the transmission seat 10, and the opening of the linear module support 26 are aligned. Then, the threaded end of the transmission pin 33 enters from the opening of the linear module support 26 and passes through the second slot 1001 of the transmission seat 10 and the first slot 101 of the lens barrel 1, and is fixed in the reserved threaded hole 2101 at the moving lens mount 21. The transmission pin 33 is located inside the opening of the linear module support 26, thus causing the linear module 25 to drive the transmission seat 10 to move left and right, and indirectly driving the moving assembly to move left and right through the transmission pin 33. The first slot 101 of the lens barrel 1 is to make room for movement. The tolerance of the outer circle of the moving lens mount 21 in contact with the inner hole of the lens barrel 1 is controlled within 0 to 0.01 mm. Calculations show that this can also ensure that the tilt is controlled within 30″.

[0075] 3. The left external thread section of the aperture 8 is screwed onto the right internal thread of the middle three-group component, which includes the middle three-group lens mount 7 and the fourth lens 31, and tightened. Then, the spring 9 is fitted onto the outer circle of the rod section on the right side of the aperture 8. The right end of the aperture 8 extends into the inner hole of the moving lens mount 21 and can slide in the inner hole. There is a gap between the outer circle wall of the right end of the aperture 8 and the inner hole wall of the moving lens mount 21, so the moving lens mount 21 can slide.

[0076] 4. After the middle three sets of components and the elastic pre-tightening unit (including the aperture 8 and the spring 9) are installed from the left side of the lens barrel 1, the middle two sets of components, the middle one sets of components, and the front set of components are installed from the left side of the lens barrel 1 in sequence. The front pressure ring 2 is threadedly connected to the inner wall of the left end of the lens barrel 1, thereby pressing the fixed lens assembly onto the pre-designed axial step inside the lens barrel 1. The rear set of components is installed from the right side of the lens barrel 1. The rear pressure ring 23 is threadedly connected to the inner wall of the right end of the lens barrel 1, thereby pressing the rear set of components onto the pre-designed axial step on the right side of the inside of the lens barrel 1. The tolerance fit between the outer circle of the lens mount in the rear set of components and the outer circle of each lens mount in the fixed lens assembly and the inner hole of the lens barrel 1 in contact with it is controlled within 0 to 0.01 mm. Before this, in the rear set of components and the fixed lens assembly, it is necessary to ensure that the optical axis of the lens is within the tolerance range of the axis of the outer circle of the lens mount, and to ensure that the two end faces of the lens mount are perpendicular to the optical axis. It is also necessary to ensure the perpendicularity of the axis of the inner hole of the lens barrel 1 itself and the contact surface.

[0077] 5. Cover plate 3 covers the opening of linear module support base 26 (i.e. the hole through which the drive pin 33 passes), and sealing plate 27 is fixed to the left side of linear module support base 26.

[0078] The structural process of this article includes: Figure 10In this configuration, the entire illumination objective lens is vertically fixed and its surface A is fixed to the inspection device (Hartmann), representing the working state of the illumination objective lens. In this state, the linear module 25 enables the moving assembly to move up and down. All other components remain stationary; only the linear module 25 moves the moving assembly vertically. Observation through the inspection device (Hartmann) shows that by continuously adjusting the position of the moving assembly through the linear module 25, the focal point of the illumination objective lens is ultimately focused onto the mask surface B. The control process of the linear module 25 utilizes existing technology.

[0079] The scope of protection of this utility model includes, but is not limited to, the above embodiments. The scope of protection of this utility model is defined by the claims. Any substitutions, modifications, or improvements to this technology that are easily conceived by those skilled in the art shall fall within the scope of protection of this utility model.

Claims

1. An electric mechanism for adjusting the air layer of an illumination objective lens, characterized in that, include: The lens barrel (1) has an inner hole extending along the optical axis, a fixed lens assembly, a movable moving assembly, a linear drive unit, a transmission pin (33), and an elastic preload unit. The fixed lens assembly is disposed inside the lens tube (1) and includes a front group component, a middle group component, a middle second group component, a middle third group component and a rear group component arranged sequentially from front to back along the optical axis; The moving assembly is located between the middle three-assembly assembly and the rear assembly, and includes a moving assembly lens mount (21) and a lens five (32) fixed thereon. The linear drive unit is fixed outside the lens barrel (1) and includes a linear module (25), a transition plate (24) and a transmission seat (10). The mover (2501) of the linear module (25) is rigidly connected to the transmission seat (10) through the transition plate (24). One end of the transmission pin (33) is fixedly connected to the moving lens mount (21), and the other end passes through the first slot (101) on the side wall of the lens barrel (1) and the second slot (1001) on the transmission seat (10). The elastic preload unit is disposed between the moving assembly and the fixed mirror assembly, and is used to apply a continuous axial preload to the moving assembly so that the transmission pin (33) is always in close contact with the inner wall of one side of the second slot (1001). The linear module (25) is used to drive the transmission seat (10) to move in a direction parallel to the optical axis. Through the transmission pin (33), the moving parts are moved synchronously in the lens barrel (1) to change the air layer thickness between it and the adjacent lens group, so as to achieve focusing.

2. The electric mechanism for adjusting the air layer of an illumination objective lens according to claim 1, characterized in that, The inner hole of the lens barrel (1) and the outer circle of the moving lens mount (21) are in a precision sliding fit, with the fit clearance controlled within the range of 0 to 0.01 mm. The tilt angle of the outer circle axis of the moving lens mount (21) relative to the inner hole axis of the lens barrel (1) is controlled within 30 arcseconds.

3. The electric mechanism for adjusting the air layer of an illumination objective lens according to claim 1, characterized in that, The elastic preload unit includes an aperture (8) and a compression spring (9); the aperture (8) is formed by a fixed connection of an external thread section and a rod section, with the external thread section screwed into the corresponding internal thread of the middle three components; the compression spring (9) is sleeved on the outer periphery of the rod section of the aperture (8) extending out of the middle three components; one end of the compression spring (9) abuts against the flange of the aperture (8) or the end face of the middle three components, and the other end abuts against the end face of the moving lens mount (21), providing a preload force to the moving components away from the middle three components; one end of the rod section of the aperture (8) extends into the inner hole of one end of the moving lens mount (21), and there is a gap between the outer wall of the rod section and the inner wall of the inner hole of the moving lens mount (21).

4. The electric mechanism for adjusting the air layer of an illumination objective lens according to claim 3, characterized in that, The spring preload force F2 provided by the elastic preload unit is always greater than the reverse load force F1 applied to the transmission seat (10) by the linear drive unit throughout the entire stroke of the moving assembly.

5. The electric mechanism for adjusting the air layer of an illumination objective lens according to claim 1, characterized in that, The moving assembly lens mount (21) and lens five (32) in the moving assembly are bonded and fixed by low-stress adhesive, and the optical axis of lens five (32) is made to coincide with the mechanical axis of the outer circle of the moving assembly lens mount (21) by image retouching process.

6. The electric mechanism for adjusting the air layer of an illumination objective lens according to claim 5, characterized in that, In the fixed lens assembly, the front lens mount (4) of the front group component is bonded to lens one (28) with low-stress adhesive, and the optical axis of lens one (28) is aligned with the mechanical axis of the outer circle of the front lens mount (4) through an image retouching process; the middle lens mount (5) of the middle group component is bonded to lens two (29) with low-stress adhesive, and the optical axis of lens two (29) is aligned with the mechanical axis of the outer circle of the middle lens mount (5) through an image retouching process; the middle lens mount (6) of the middle group component is bonded to lens three (20) with low-stress adhesive. And through image retouching process, the optical axis of lens three (20) is made to coincide with the mechanical axis of the outer circle of the middle second group lens mount (6); the middle third group lens mount (7) and lens four (31) in the middle third group component are bonded and fixed with low stress adhesive, and through image retouching process, the optical axis of lens four (31) is made to coincide with the mechanical axis of the outer circle of the middle third group lens mount (7); the rear group lens mount (22) and lens six (34) in the rear group component are bonded and fixed with low stress adhesive, and through image retouching process, the optical axis of lens six (34) is made to coincide with the mechanical axis of the outer circle of the rear group lens mount (22); The middle three-group component, the middle two-group component, the middle one-group component, and the front group component are sequentially inserted into the lens tube (1) from the front end of the lens tube (1), and the front pressure ring (2) is screwed into the front end of the lens tube (1) by thread, thereby pressing the front group component, the middle one-group component, the middle two-group component, and the middle three-group component as a whole onto the axial step pre-designed inside the lens tube (1); the outer circular wall of the front group lens mount (4), the middle one-group lens mount (5), the middle two-group lens mount (6), and the middle three-group lens mount (7) is fitted with a small clearance with the inner hole wall of the front end of the lens tube (1); The rear assembly is inserted into the lens barrel (1) from the rear end of the lens barrel (1), and the rear pressure ring (23) is screwed into the rear end of the lens barrel (1) by the thread, thereby pressing the end face of the rear lens mount (22) of the rear assembly onto the pre-designed axial step inside the lens barrel (1); the outer circular wall of the rear lens mount (22) is fitted with the inner wall of the rear end of the lens barrel (1) with a small clearance.

7. The electric mechanism for adjusting the air layer of an illumination objective lens according to claim 1, characterized in that, Both the lens barrel (1) and the moving lens mount (21) are made of 304 stainless steel.

8. The electric mechanism for adjusting the air layer of an illumination objective lens according to claim 1, characterized in that, It also includes a linear module support base (26), a sealing plate (27) and a cover plate (3). The linear module support base (26) is used to install and support the linear module (25). The linear module support base (26) is fixed to the outside of the lens barrel (1) by fasteners. The linear module (25), the transition plate (24) and the transmission seat (10) are all located inside the linear module support base (26). The linear module support base (26) has two openings, which are aligned with the positions of the transmission pins (33) respectively. The openings are covered by the cover plate (3).

9. The electric mechanism for adjusting the air layer of an illumination objective lens according to claim 1, characterized in that, The transmission pin (33) is formed by connecting the rod body and the threaded end. The threaded end is threadedly connected to the reserved threaded hole (2101) on the moving lens mount (21). The end face of the rod body connected to the threaded end is tightly fitted to the outer end face of the reserved threaded hole (2101) on the moving lens mount (21). The second slot (1001) on the transmission seat (10) is a waist-shaped hole that can accommodate one end of the transmission pin (33).

10. The electric mechanism for adjusting the air layer of an illumination objective lens according to claim 9, characterized in that, There are two transmission pins (33), two reserved threaded holes (2101) on the moving lens mount (21), and two second slots (1001) on the transmission seat (10); the first slot (101) on the side wall of the lens barrel (1) is a long strip hole, and there are two of them.

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