Lens focal plane adjusting mechanism

Abstract

The utility model discloses a lens focal plane adjusting mechanism, include: inner tube, its one end is equipped with the direction part, the other end fixed connection dial, the outer wall of inner tube is equipped with outer thread, the inner wall of outer connecting sleeve is equipped with the inner thread with outer thread cooperation, the direction part of inner tube inserts into outer connecting sleeve and can axial movement through thread cooperation, pre -tightening structure, including the annular screw groove of setting up in the outer wall of direction part, the screw hole of setting up in the outer wall of outer connecting sleeve and the first screw of passing through screw hole and extending into annular screw groove, scale indicating mechanism, including the annular first scale line of setting up in the circumference of dial and the second scale line of setting up in the outer wall of outer connecting sleeve, the utility model has the beneficial effect that improves focusing accuracy, reduces the empty return phenomenon, shortens the time of focusing, simplifies the operation process, realizes the quantization and record of focal plane adjustment, strengthens the structure stability and reliability, and the wider applicability is more, reduces the manpower cost.

Description

Technical Field

[0001] This utility model relates to the field of optical instrument technology, specifically to a lens focal plane adjustment mechanism. Background Technology

[0002] In the production, assembly, and debugging of precision optical instruments, especially lens modules, precise adjustment of the focal plane is a crucial step in ensuring image quality. Currently, the industry commonly uses two main focal plane adjustment methods.

[0003] The first method uses focal plane shims for adjustment. This method involves machining focal plane shims of different thicknesses, placing them between the lens flange and the machine tool during actual debugging, and adjusting the optical path length by increasing or decreasing the number of shims or replacing them with shims of different thicknesses, thereby achieving focal plane adjustment. However, this method has obvious drawbacks: each adjustment requires disassembling and installing the shims, a cumbersome and time-consuming process, requiring multiple attempts by the debugging personnel to achieve the desired effect. The second method uses a threaded connection between the inner cylinder and the outer connecting sleeve. Rotating the outer connecting sleeve roughly moves the inner cylinder axially, thereby adjusting the focal plane. For example, Chinese patent document CN217846773U discloses a telescope back focal length precision adjuster, which includes a lens mount, a mounting base, and an adjustment mechanism composed of an internally threaded adjusting ring and a fixing ring, achieving precise adjustment of the lens position through threaded engagement. Although this method is relatively convenient for adjustment, in actual operation, the presence of gaps in the threaded engagement often results in a "free return" phenomenon. When the operator releases the screw after rotating it to the theoretical focal position, the inner cylinder may deviate from the optimal position due to gravity or the rebound effect of the gap, resulting in low focusing accuracy and excessive reliance on the operator's experience and feel.

[0004] Furthermore, neither of the two existing technical solutions can directly and quantitatively record the specific rotation angle or displacement during the focal plane adjustment process. This makes it inconvenient to reproduce the debugging results and compare debugging data between different devices or batches. It also fails to provide accurate parameter references for subsequent production and maintenance, increasing labor costs. Utility Model Content

[0005] One objective of this invention is to solve at least one of the problems in the prior art, namely, long adjustment time, low accuracy, and inability to record adjustment results, and to provide a lens focal plane adjustment mechanism that can increase adjustment accuracy.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a lens focal plane adjustment mechanism, comprising: an inner cylinder, one end of which is provided with a guide portion, and the other end is fixedly connected to a scale, the outer wall of the inner cylinder being provided with an external thread; an outer connecting sleeve, the inner wall of which is provided with an internal thread that mates with the external thread, the guide portion of the inner cylinder being inserted into the outer connecting sleeve and being axially movable through the threaded engagement; a pre-tightening structure, including an annular screw groove formed on the outer wall of the guide portion, a screw hole formed on the outer wall of the outer connecting sleeve, and a first screw passing through the screw hole and extending into the annular screw groove; and a scale indicating mechanism, including an annular first scale line provided on the circumferential surface of the scale, and a second scale line provided on the outer wall of the outer connecting sleeve.

[0007] Preferably, the dial is fixedly connected to the lens barrel by a second screw.

[0008] Preferably, a sealing groove is provided on the outer wall of the guide portion, and a sealing ring is provided inside the groove.

[0009] Preferably, the width of the annular screw groove is greater than the diameter of the first screw.

[0010] Preferably, the inner cylinder is made of copper and the outer connecting sleeve is made of aluminum.

[0011] Preferably, the external thread and the internal thread are ground together, and the gap between them is 0.01-0.02 mm.

[0012] Preferably, the first scale line is evenly distributed along the circumference, with a scale interval of 3°-8°.

[0013] Preferably, the number of the second scale lines is 3-5, wherein the length of the center scale line is greater than that of the scale lines on both sides.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. Improved focusing accuracy and reduced backlash: By employing ground internal and external threads, supplemented by a pre-tightening structure, the gap between threads and backlash are effectively reduced, resulting in more precise focus adjustment. Compared to traditional threaded connections and shim adjustments, this significantly improves focusing accuracy and reduces reliance on operator experience.

[0015] 2. Reduced focusing time and simplified operation: This mechanism can directly adjust the axial displacement by rotating the inner cylinder or lens barrel, and the use of the pre-tightening structure ensures that the adjusted position can be stably fixed, avoiding the time loss and cumbersome steps caused by repeated disassembly and assembly in the traditional shim adjustment method, and greatly shortening the debugging cycle.

[0016] 3. Quantification and Recording of Focal Surface Adjustment: A complete scale indication mechanism is formed by setting a first annular scale line on the dial and a second scale line on the outer connecting sleeve, enabling precise reading and recording of the relative displacement or rotation angle of the focal surface adjustment. This provides quantitative data for debugging personnel, facilitating data comparison, experience accumulation, and standardization of production parameters.

[0017] 4. Enhanced Structural Stability and Reliability: The annular screw groove design in the pre-tightening structure avoids potential damage and deformation caused by the first screw directly contacting the inner cylinder guide area. Furthermore, the width of the annular screw groove is greater than the diameter of the first screw, ensuring that the first screw can still be inserted into the groove and secure the inner cylinder 5 even after the inner cylinder has moved axially a certain focusing distance within the outer connecting sleeve. Using different materials—a copper inner cylinder and an aluminum outer connecting sleeve—utilizes the difference in hardness to prevent thread seizing, further enhancing reliability.

[0018] 5. Wider applicability and reduced labor costs: The focus adjustment process is visualized and quantified, reducing reliance on the experience of technical personnel. This allows non-professionals to perform precise focus adjustment under certain guidance, thereby reducing the company's training and labor costs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a lens focal plane adjustment mechanism.

[0020] Figure 2 This is a schematic diagram of the inner cylinder in a lens focal plane adjustment mechanism.

[0021] Figure 3 This is a schematic diagram of the structure of the outer connecting sleeve in a lens focal plane adjustment mechanism.

[0022] Figure 4 This is a schematic diagram of the guide section in a lens focal plane adjustment mechanism.

[0023] In the diagram: 1. Fixed flange; 2. Sealing ring; 3. First screw; 4. Outer connecting sleeve; 5. Inner cylinder; 6. Lens barrel; 7. Guide part; 8. Sealing groove; 9. Dial; 10. First scale line; 11. Second screw; 12. External thread; 13. Internal thread; 14. Annular screw groove; 15. Screw hole; 16. Second scale line. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0025] For ease of understanding and description, in the following embodiments, we will use a preferred embodiment to illustrate in detail the structure, connection relationship, working principle and the effects that can be achieved of this utility model.

[0026] Reference Figures 1 to 4 The lens focal plane adjustment mechanism provided by this utility model mainly includes an inner cylinder 5, an outer connecting sleeve 4, a pre-tightening structure, and a scale indicator mechanism.

[0027] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in this utility model, based on the technical solution and inventive concept of this utility model, should be covered within the protection scope of this utility model. Structural composition and connection relationships: One end of the inner cylinder 5, near the fixed flange 1, is provided with a guide portion 7, and the other end, away from the fixed flange 1, is fixedly connected to a dial 9. The outer wall of the inner cylinder 5, specifically the outer wall between the guide portion 7 and the dial 9, is provided with external threads 12. Preferably, the inner cylinder 5 is made of copper.

[0028] The inner wall of the outer connecting sleeve 4 is provided with an internal thread 13 that mates with the external thread 12. The guide portion 7 of the inner cylinder 5 can be inserted into the interior of the outer connecting sleeve 4, and the axial movement of the inner cylinder 5 within the outer connecting sleeve 4 is achieved through the threaded engagement of the external thread 12 and the internal thread 13. Preferably, the outer connecting sleeve 4 is made of aluminum. By using a copper inner cylinder 5 and an aluminum outer connecting sleeve 4, the difference in hardness between the two materials can effectively reduce the tendency for adhesion during threaded engagement, prevent the threads from "seizing up," and thus improve the reliability and service life of the mechanism.

[0029] Furthermore, the external thread 12 and the internal thread 13 preferably employ a ground fit, with the gap between them controlled between 0.01 mm and 0.02 mm. This precise ground fit, compared to a conventional thread fit, significantly reduces thread backlash and improves the fineness of adjustment. Simultaneously, maintaining a minute gap of 0.01 mm to 0.02 mm is necessary to prevent thread jamming should a small amount of debris be generated.

[0030] The pre-tightening structure is used to fix the inner cylinder 5 or provide appropriate friction after the focus adjustment is completed, to prevent accidental displacement or backlash. This pre-tightening structure includes: an annular screw groove 14 formed on the outer wall of the guide portion 7; a screw hole 15 formed on the outer wall of the outer connecting sleeve 4; and a first screw 3 passing through the screw hole 15 and extending into the annular screw groove 14. The width of the annular screw groove 14 is preferably designed to be greater than the diameter of the first screw 3. This annular groove design allows the first screw 3 to slide within the annular groove 14 during axial movement of the inner cylinder 5 without hindering the axial displacement of the inner cylinder 5, facilitating the movement of the inner cylinder 5 for focus adjustment. It also avoids damage, deformation, or debris that may result from the screw directly contacting the outer surface of the guide portion 7, thus ensuring the coaxiality of the front guide area and smooth engagement of the ground threads. In a preferred embodiment, multiple screw holes 15, such as two, can be formed and distributed at a 90° angle along the circumference to accommodate multiple first screws 3, thereby providing a more uniform and stable pre-tightening force.

[0031] The scale indicator mechanism is used to quantify the displacement or rotation angle of the focal plane adjustment. This mechanism includes: a first annular scale line 10 disposed on the circumferential surface of the scale dial 9; and a second scale line 16 disposed on the outer wall of the outer connecting sleeve 4. The first scale line 10 is preferably evenly distributed along the circumference of the scale dial 9. To achieve higher adjustment accuracy, the scale interval of the first scale line 10 is preferably 3°-8°. In a specific embodiment, the number of first scale lines 10 is 72, meaning that the angular interval corresponding to each scale line is 360° / 72=5°. The number of second scale lines 16 can be set according to actual needs, preferably 3-5, for example, 5. The length of the central scale line can be designed to be greater than that of the scale lines on both sides to facilitate visual identification and positioning. This set of scale lines is usually arranged on the easily observable side of the outer connecting sleeve 4. To ensure the clarity and durability of the scale lines, the groove depth of the first scale line 10 and the second scale line 16 is preferably 0.3 mm, and the groove width is preferably 0.5 mm. Such depth and width can ensure that the scale lines are not easily worn during long-term use and have good visual recognition.

[0032] During assembly, the guide portion 7 of the inner cylinder 5 can be vertically inserted into the outer connecting sleeve 4 from bottom to top. A sealing groove 8 is provided on the outer wall of the guide portion 7 of the inner cylinder 5, within which a sealing ring 2 can be installed. This sealing ring 2 provides a certain degree of airtightness or dustproof effect, while also further guiding and stabilizing the guide portion 7. The dial 9 of the inner cylinder 5 can also be fixedly connected to the outer mirror tube 6 via a second screw 11. The outer connecting sleeve 4 can be directly fixed to the lower surface of the equipment's fixing flange 1.

[0033] Working principle and adjustment process: When focal plane adjustment is required, the operator first loosens the first screw 3 in the pre-tightening structure to release the pre-tightening of the inner cylinder 5. At this time, the inner cylinder 5 and its fixed lens barrel 6 can move or rotate axially relative to the outer connecting sleeve 4. The operator can rotate the lens barrel 6, thereby driving the inner cylinder 5 and the external thread 12 to perform threaded transmission within the outer connecting sleeve 4, thus achieving axial displacement of the inner cylinder 5 and adjusting the focal plane.

[0034] During adjustment, the operator can visually align or read the first scale line 10 on the surface of the dial 9 with the second scale line 16 on the outer connecting sleeve 4. Since the first scale line 10 is evenly distributed along the circumference and the second scale line 16 provides a reference, the operator can accurately record the angle of rotation from the starting position to the target focal plane position, or assess its axial displacement. For example, when the first scale line 10 of the inner cylinder 5 has 72 evenly distributed grooves, and the second scale line 16 of the outer connecting sleeve 4 has 5 grooves, the operator can clearly determine the accuracy and specific parameters of the focal plane adjustment.

[0035] Once the focal plane is adjusted to the optimal position, the operator can tighten the first screw 3. Since the first screw 3 passes through the threaded hole 15 of the outer connecting sleeve 4 and extends into the annular screw groove 14 of the inner cylinder 5, tightening the first screw 3 will cause the screw tip to press against the side wall of the annular screw groove 14, thereby applying a preload to the inner cylinder 5. This preload eliminates minor wobble that may be caused by thread clearance and firmly locks the axial position of the inner cylinder 5, thus ensuring a stable and reliable focal plane position after adjustment and preventing displacement due to accidental vibration or gravity.

[0036] The technical effects of this invention are significant: By employing a precision-ground thread fit, this mechanism effectively increases the accuracy of focus adjustment compared to traditional threaded connections. Furthermore, its adjustment operation is smooth and direct, avoiding the cumbersome process of shim adjustment. The introduction of the scale indicator mechanism allows for precise recording of the rotation angle or displacement of each focus adjustment, providing quantitative data support for adjustment personnel. This not only accelerates the adjustment process but also provides valuable data references for subsequent production consistency control, problem tracing, and parameter optimization. It effectively reduces over-reliance on the experience of adjustment personnel, thereby achieving the expected goals of shortening focus adjustment time, increasing adjustment accuracy, and facilitating the recording of adjustment results.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A lens focal plane adjustment mechanism, characterized in that, include: The inner cylinder has a guide at one end and a scale dial fixedly connected at the other end. The outer wall of the inner cylinder has external threads. An outer connecting sleeve has an inner thread on its inner wall that mates with the external thread. The guide portion of the inner cylinder is inserted into the outer connecting sleeve and can move axially through the threaded engagement. The pre-tightening structure includes an annular screw groove on the outer wall of the guide portion, a screw hole on the outer wall of the outer connecting sleeve, and a first screw that passes through the screw hole and extends into the annular screw groove. The scale indicator mechanism includes a first annular scale line on the circumferential surface of the scale dial and a second scale line on the outer wall of the outer connecting sleeve.

2. The lens focal plane adjustment mechanism according to claim 1, characterized in that, The dial is fixedly connected to the lens barrel by a second screw.

3. The lens focal plane adjustment mechanism according to claim 1, characterized in that, The outer wall of the guide section is provided with a sealing groove, and a sealing ring is installed inside it.

4. The lens focal plane adjustment mechanism according to claim 1, characterized in that, The width of the annular screw groove is greater than the diameter of the first screw.

5. The lens focal plane adjustment mechanism according to claim 1, characterized in that, The inner cylinder is made of copper, and the outer connecting sleeve is made of aluminum.

6. The lens focal plane adjustment mechanism according to claim 1, characterized in that, The external thread and the internal thread are ground together, with a clearance of 0.01–0.02 mm.

7. The lens focal plane adjustment mechanism according to claim 1, characterized in that, The first scale line is evenly distributed along the circumference, with a scale interval of 3°-8°.

8. The lens focal plane adjustment mechanism according to claim 1, characterized in that, The number of the second scale lines is 3-5, with the center scale line being longer than the scale lines on both sides.

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