Lens optical axis consistency inspection device

Abstract

The utility model provides a lens optical axis consistency inspection device relates to lens optical axis consistency technical field, including the optical platform as the installation reference, the target plate structural member with first cross mark is fixed on the platform, and with the target plate interval preset distance is used for installing the fixed seat structural member of lens module to be measured, its core lies in through the position deviation between the target plate mark image of lens module collection and the second mark of sensor self generation, evaluates lens optical axis consistency. The utility model discloses utilize simple mechanical structure to replace traditional expensive complex instrument, through the unique double mark comparison principle, can realize quick qualitative screening, and can also carry out accurate quantitative calculation. The device has the prominent advantages of low cost, simple operation, high detection efficiency. The design effectively solves the problem of production line batch lens center consistency rapid detection, significantly reduces the detection threshold and cost, and has important significance to the improvement of product quality control level.

Description

Technical Field

[0001] This utility model mainly relates to the field of lens optical axis consistency technology, and specifically to a lens optical axis consistency inspection device. Background Technology

[0002] In the fields of optical lens manufacturing and camera module assembly, the center alignment (i.e., concentricity) of the lens's optical axis and its mechanical mounting reference plane is a crucial technical indicator. Deviations in optical axis alignment directly lead to a series of problems such as image center shift, uneven image quality, and vignetting, severely impacting image quality. During mass production, ensuring good consistency between batches of lenses is key to guaranteeing product interchangeability and overall quality stability.

[0003] Currently, the inspection of lens optical axis consistency largely relies on some high-precision traditional methods. These include using a precision rotary table with a high-resolution sensor, or a coordinate measuring machine (CMM) for precision mechanical scanning, and even complex dedicated optical testing systems. While these methods achieve high measurement accuracy, they generally suffer from the following inherent drawbacks: First, these devices are typically expensive, with high purchase and maintenance costs, significantly increasing production costs; second, the operation methods are complex, requiring specialized technicians in specific laboratory environments, making them difficult to implement on production sites; and finally, the entire inspection process is time-consuming and inefficient, failing to meet the rapid, full-scale, or large-batch sampling requirements of modern production lines.

[0004] It should be noted that the above content falls within the scope of technical knowledge of those skilled in the art. Due to the vast and complex nature of the technical content in this field, the above content of this application does not necessarily constitute prior art. Utility Model Content

[0005] 1. The technical problem to be solved by the utility model: This utility model provides a lens optical axis consistency inspection device to solve the technical problems existing in the background art.

[0006] 2. Technical Solution: To achieve the above objectives, the technical solution provided by this utility model is: a lens optical axis consistency inspection device, including an optical platform as the mounting reference surface of the device; A target plate structure is fixedly mounted on the optical platform, and the side of the target plate structure facing the test direction is provided with a first mark as an optical reference. A fixed base structure is fixedly mounted on the optical platform and spaced apart from the target plate structure along the optical path by a preset distance. The fixed base structure is used to support and fix the lens module to be tested. The image sensor built into the lens module under test generates a second mark as an electronic reference. The center consistency of the lens installed in the lens module under test is evaluated by comparing the positional deviation between the image of the first mark acquired by the lens module under test and the second mark.

[0007] The optical platform described in this application provides a flat and stable reference plane. The target plate structure is securely mounted to one end of the optical platform by screws. A high-precision first cross mark is machined on the target plate structure, which serves as a fixed optical reference for detection.

[0008] The mounting base structure is also mounted on the optical platform with screws, maintaining a certain distance from the target plate structure. During installation, precision measuring tools must be used to ensure that the crosshair center of the target plate structure and the reference center of the mounting base structure used to mount the product under test are on the same straight line, i.e., coaxial. This relative distance L is accurately measured and recorded.

[0009] During testing, the lens module under test is fixed to the mounting bracket structure using its dedicated mounting screws, and a display device is placed on its side. Upon power-up, the image sensor inside the lens module under test begins operation, and its driving software generates a second crosshair mark at the center of the image on the display screen. Simultaneously, the lens under test images the first crosshair mark on the target plate structure in front of it.

[0010] Ideally, if the lens's optical axis is perfectly perpendicular to its mechanical mounting reference plane and without any offset, the image of the first crosshair on the target plate should fall perfectly in the center of the image sensor, that is, completely coincident with the software-generated second crosshair. However, errors present in actual production can cause optical axis deviation, thus causing the image of the first crosshair to deviate from the second crosshair. This offset directly reflects the consistency error of the lens's optical axis.

[0011] Operators can quickly and intuitively determine the degree of dispersion in the centering consistency of lenses from the same batch by observing changes in offset on the screen after rapidly changing different lenses. The smaller the offset fluctuation, the better the consistency of the batch of lenses.

[0012] The device has an extremely simple structure, consisting of only a platform, target plate, and fixed base, among a few mechanical parts. Its manufacturing cost is far lower than that of traditional precision rotary tables or coordinate measuring machines. The operation is simple, requiring no complex debugging; ordinary production line workers can operate it after brief training, significantly lowering the technical threshold and dependence on a specialized environment. Its features of "quick changeover and intuitive comparison" make it ideal for large-scale, rapid screening and quality monitoring of lenses on the production line, greatly improving inspection efficiency and providing an effective tool for controlling product quality and reducing production costs.

[0013] Furthermore, the optical platform has a series of threaded holes with standard spacing on its surface, and the bottom of the target plate structure and the fixed base structure are provided with through holes that mate with the threaded holes, and are detachably connected by screws.

[0014] Furthermore, both the first mark and the second mark are cross-shaped targets.

[0015] Furthermore, the target plate structure includes an L-shaped fixing plate, the bottom of which is symmetrically provided with through holes that are detachably connected to the threaded holes, and the L-shaped fixing plate is provided with the first mark facing the fixing base structure.

[0016] Furthermore, the fixing base structure includes a convex positioning block, on which connecting slots are symmetrically opened on both sides of the bottom for fixing with the optical platform; a positioning hole is machined at the top center of the convex positioning block, and the lens module under test cooperates with the positioning hole through its own interface structure to achieve detachable connection and precise positioning.

[0017] 3. Beneficial effects: Compared with the prior art, the technical solution provided by this utility model has the following advantages: This invention features a reasonable design. The device achieves rapid detection of lens optical axis consistency through a simple mechanical structure combined with the principle of double cross-target comparison. Its simple structure results in significantly lower manufacturing costs compared to traditional precision instruments, and its easy operation greatly reduces the technical requirements for operators and testing time, making it particularly suitable for rapid batch screening on production lines.

[0018] The modular design gives the device excellent versatility and expandability. One set of equipment can be adapted to lenses of different specifications and can be expanded into a multi-station parallel inspection system, which greatly improves equipment utilization and inspection efficiency, and has important practical value for improving product quality control and production efficiency.

[0019] It should be noted that the structures not described in this utility model are the same as or can be implemented using existing technology, and will not be elaborated here, as they do not involve the design points and improvement directions of this utility model. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This utility model Figure 1 Enlarged schematic diagram of the structure at point A; Figure 3 This is a schematic diagram of the structure of this utility model from another angle.

[0021] Figure label: 1. Optical platform; 2. Target plate structure; 21. L-shaped fixing plate; 22. Through hole; 3. Fixing base structure; 31. Convex positioning block; 32. Connecting through groove; 33. Positioning hole; 4. Lens module under test. Detailed Implementation

[0022] To facilitate understanding of this utility model, a more comprehensive description of the utility model will be given below with reference to the accompanying drawings, which show several embodiments of the utility model. However, the utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the utility model will be more thorough and complete.

[0023] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "page", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] In this utility model, unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," "fixed," "provided with," and "located in" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0026] It should be noted that the structures not described in this utility model do not involve the design points and improvement directions of this utility model, and can all adopt existing technologies known to those skilled in the art.

[0027] The specific implementation of this utility model will be described in detail below with reference to specific embodiments.

[0028] See attached document Figure 1-3 A lens optical axis consistency inspection device includes an optical platform 1, which serves as the mounting reference surface of the device; The target plate structure 2 is fixedly mounted on the optical platform 1, and the side of the target plate structure 2 facing the test direction is provided with a first mark as an optical reference. The fixed base structure 3 is fixedly mounted on the optical platform 1 and spaced apart from the target plate structure 2 along the optical path by a preset distance. The fixed base structure 3 is used to support and fix the lens module 4 to be tested. The image sensor built into the lens module under test 4 generates a second mark as an electronic reference; the center consistency of the lens installed in the lens module under test 4 is evaluated by comparing the positional deviation between the image of the first mark acquired by the lens module under test 4 and the second mark.

[0029] In this embodiment, the optical platform 1 provides a flat and stable reference plane. The target plate structure 2 is securely mounted to one end of the optical platform 1 with screws. The target plate structure 2 is machined with a high-precision first cross mark, which serves as a fixed optical reference for detection.

[0030] The mounting base 3 is also mounted on the optical platform 1 with screws, maintaining a certain distance from the target plate 2. During installation, precision measuring tools such as height gauges and laser alignment instruments are used to ensure that the crosshair center of the target plate 2 and the reference center of the mounting base 3 for mounting the product under test are on the same straight line, i.e., coaxial. This relative distance L is accurately measured and recorded.

[0031] During testing, the lens module under test 4 is fixed to the mounting base structure 3 using its dedicated mounting screws, and a display device is placed on its side. After power-on, the image sensor inside the lens module under test 4 begins to work, and its driving software generates a second cross mark at the center of the image on the display screen. At the same time, the lens under test will image the first cross mark on the target plate structure 2 in front of it. The image sensor can be, for example, a CMOS sensor.

[0032] Ideally, if the lens's optical axis is perfectly perpendicular to its mechanical mounting reference plane and without any offset, the image of the first crosshair on the target plate should fall perfectly at the center of the image sensor, that is, completely coincident with the software-generated second crosshair. However, errors present in actual production can cause optical axis deviation, thus causing the image of the first crosshair to deviate from the second crosshair. This offset directly reflects the consistency error of the lens's optical axis; this offset is the difference between the centers of the two crosshairs, expressed in pixels.

[0033] Operators can quickly and intuitively determine the degree of dispersion in the centering consistency of lenses from the same batch by observing changes in offset on the screen after rapidly changing different lenses. The smaller the offset fluctuation, the better the consistency of the batch of lenses.

[0034] The device described in this embodiment has an extremely simple structure, consisting of only a platform, target plate, and fixed base, among other mechanical components. Its manufacturing cost is far lower than that of traditional precision rotary tables or coordinate measuring machines. The operation is simple, requiring no complex debugging; ordinary production line workers can operate it after brief training, significantly reducing the technical threshold and dependence on a specialized environment. Its features of "quick replacement and intuitive comparison" make it ideal for large-scale, rapid screening and quality monitoring of lenses on the production line, greatly improving inspection efficiency and providing an effective tool for controlling product quality and reducing production costs.

[0035] The optical platform 1 has a series of threaded holes with standard spacing on its surface. The target plate structure 2 and the mounting base structure 3 have through holes 22 at their bottoms that mate with these threaded holes, and are detachably connected by screws. In this embodiment, the surface of the optical platform 1 is precision-machined and has a large number of regularly distributed threaded holes, typically arranged at a standard grid spacing, for example, every 25 millimeters or one inch. The target plate structure 2 and the mounting base structure 3 have corresponding through holes 22 at their base positions. By screwing in screws, they can be securely installed at any desired position on the optical platform 1. When inspecting lenses of different models or focal lengths, the operator can first determine the approximate distance between the target plate structure 2 and the mounting base structure 3 based on the reference focal length of the lens to be tested. Then, the fixing screws are loosened, and the target plate structure 2 and the mounting base structure 3 are slid along a preset guide rail or alignment scale on the optical platform 1 to the vicinity of the target position. Fine adjustments are then made using the precision threaded holes on the platform, and finally, the surfaces are locked. To ensure the accuracy of the optical path reference, a high-precision laser alignment tool or a long-rod dial indicator can be used to assist in adjustment, ensuring that the center of the crosshair on the target plate structure 2 is strictly coaxial with the mounting center of the fixed base structure 3. By flexibly adjusting the relative positions of the two structures, the same device can meet the inspection needs of various lenses, from short-focal to long-focal, greatly improving equipment utilization and avoiding the cost of customizing inspection fixtures for different products. Simultaneously, this modular connection method facilitates maintenance and component replacement. More importantly, it provides convenience for batch inspection: multiple fixed stations can be set up simultaneously on the optical platform 1, each station containing a target plate and a fixed base, thereby enabling parallel and rapid inspection of multiple lens modules, significantly increasing inspection efficiency.

[0036] Both the first and second marks are cross-shaped targets. The first mark set on the target plate structure 2 and the second mark displayed on the screen of the lens module 4 under test both adopt a cross-shaped pattern with a precise center of symmetry. This cross-shaped target can be made on the surface of the target plate by precision machining, etching, or high-precision printing to ensure the straightness of the lines and the clarity of the edges. The electronic cross-shaped target displayed on the screen is generated in real time by image processing software superimposed at the center of the video stream. When there is an optical axis deviation in the lens, the image of the physical cross-shaped target captured by the camera will deviate from the electronic cross-shaped target superimposed at its center. This deviation can be decomposed into two components in the horizontal and vertical directions. The cross-shaped structure allows the offset in these two directions to be measured independently and accurately, thereby comprehensively characterizing the optical axis error and facilitating visual observation.

[0037] The target plate structure 2 includes an L-shaped fixing plate 21. The bottom of the L-shaped fixing plate 21 has symmetrical through holes 22 that are detachably connected to the threaded holes. The L-shaped fixing plate 21 has the first mark facing the fixing base structure 3. In this embodiment, the target plate structure 2 is composed of an L-shaped fixing plate 21 integrally formed or precision assembled. Two through holes 22 are symmetrically machined on the horizontal base of the L-shaped fixing plate 21, and their spacing matches the spacing of the standard threaded holes on the optical platform 1. By selecting different threaded hole positions, the longitudinal position of the target plate on the platform can be adjusted. The vertical plate is precision machined to ensure that its front surface is strictly perpendicular to the bottom surface of the horizontal base. A cross-shaped target as an optical reference is attached to or directly machined on this front surface.

[0038] The mounting base structure 3 includes a convex positioning block 31. Symmetrical connecting slots 32 are formed on both sides of the bottom of the convex positioning block 31 for fixing it to the optical platform 1. A positioning hole 33 is machined at the center of the top of the convex positioning block 31. The lens module 4 under test is detachably connected and precisely positioned by engaging with the positioning hole 33 through its own interface structure. In this embodiment, the core of the mounting base structure 3 is the convex positioning block 31. The bottom of the positioning block is designed with a wide base, and two sets of connecting slots 32 are symmetrically formed on both sides of the base. Screws pass through these connecting slots 32 to firmly connect it to the optical platform 1, ensuring overall stability. The upper part of the positioning block is a raised cylindrical or rectangular column, and a positioning hole 33 matching the interface of the lens module 4 under test is precisely machined at the center of its top surface. The dimensional tolerance of the positioning hole 33 is strictly controlled and can be serialized according to the standard interfaces of different lens modules.

[0039] The following section describes the specific testing method for the lens optical axis consistency device, based on the aforementioned apparatus: First, the device is calibrated. The target plate structure 2 and the mounting base structure 3 are installed on the optical platform 1, and fine-tuned using tools such as a laser alignment instrument to ensure that the first mark on the target plate is strictly coaxial with the reference center of the mounting base structure 3 used to install the lens module. The preset distance L between the two is then accurately measured using gauge blocks or a laser rangefinder.

[0040] Next, installation and numbering are carried out. Each batch of lens modules to be tested is uniquely numbered, such as A01, A02, etc. The first module with the lens to be tested is securely mounted on the mounting bracket 3, and its video output interface is connected to an image display, such as a high-definition monitor.

[0041] Next, image acquisition and display are performed. Power on the lens module 4 under test to acquire the image of the target plate mark in front. At this time, a second mark is generated in the center of the display screen by the internal circuitry or software of the module, and the image of the first mark captured by the lens is also displayed on the screen.

[0042] Next, the deviation is acquired. The operator or machine vision system uses image processing algorithms to accurately calculate the positional deviation (X, Y) between the image center of the first marker and the center of the second marker in the pixel coordinate system.

[0043] Finally, record and evaluate the results. Record the deviation (X, Y) and its correspondence with the module number A01 currently being tested. Repeat the above steps for modules A02, A03, etc., to complete the testing of the entire batch of lenses.

[0044] In an example implementation, the pixel deviation P of module A01 is obtained. P is obtained through a composite vector, as shown in the following formula: ; Perform quantitative calculations: a. Obtain the physical size S of a single pixel of the image sensor used in the module, for example, 2.0 micrometers / pixel, which is a known specification parameter.

[0045] b. Call up the precise distance L measured during the calibration phase, for example, 500.0 mm.

[0046] c. Calculate the actual physical offset D of the light spot on the sensor's photosensitive surface: D = P × S. If P is 100 pixels, then D = 100 × 2.0 μm = 0.2 mm.

[0047] d. Calculate the tilt angle E of the optical axis of the lens under test relative to its mechanical mounting surface: E = arctan(D / L). Substituting the values, E = arctan(0.2 / 500) ≈ arctan0.0004 ≈ 0.0229°.

[0048] Finally, the calculated tilt angle E=0.0229° was used as the core evaluation index and recorded along with the number A01. The beneficial effect of this quantitative method is that it transforms the pixel deviation of the image into an absolute angle value with clear physical meaning, independent of sensor resolution. This value provides reliable data support for lens design verification and precise improvement of assembly processes, achieving a leap from qualitative judgment of "whether it is qualified" to precise measurement of "how much deviation."

[0049] The above-described embodiments are merely illustrative of certain implementations of this utility model, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A lens optical axis consistency inspection device, characterized in that: include The optical platform (1) serves as the mounting reference surface for the device; The target plate structure (2) is fixedly mounted on the optical platform (1), and the side of the target plate structure (2) facing the test direction is provided with a first mark as an optical reference; The fixed base structure (3) is fixedly set on the optical platform (1) and spaced apart from the target plate structure (2) by a preset distance along the optical path direction. The fixed base structure (3) is used to support and fix the lens module (4) to be tested. The image sensor built into the lens module (4) generates a second mark as an electronic reference; the center consistency of the lens installed in the lens module (4) is evaluated by comparing the positional deviation between the image of the first mark acquired by the lens module (4) and the second mark.

2. The lens optical axis consistency inspection device according to claim 1, characterized in that: The optical platform (1) has a series of threaded holes with standard spacing on its surface. The target plate structure (2) and the fixed base structure (3) have through holes (22) that cooperate with the threaded holes at their bottoms, and are detachably connected by screws.

3. The lens optical axis consistency inspection device according to claim 1, characterized in that: Both the first mark and the second mark are cross-shaped targets.

4. The lens optical axis consistency inspection device according to claim 2, characterized in that: The target plate structure (2) includes an L-shaped fixing plate (21). The bottom of the L-shaped fixing plate (21) has symmetrical through holes (22) that are detachably connected to the threaded holes. The L-shaped fixing plate (21) is provided with the first mark facing the fixing seat structure (3).

5. The lens optical axis consistency inspection device according to claim 1, characterized in that: The fixed base structure (3) includes a convex positioning block (31), and the bottom two sides of the convex positioning block (31) are symmetrically provided with connecting through slots (32) for fixing with the optical platform (1); the top center of the convex positioning block (31) is machined with a positioning hole (33), and the lens module (4) under test is detachably connected and precisely positioned by cooperating with the positioning hole (33) through its own interface structure.

Images