Process knowledge-Mobile phone lens assembly process and process
July 23, 2023
1. Introduction to the composition and positioning of the lens
The lens may have a structure of 4P, 5P or even 6P due to factors such as pixels, specifications, standards, etc., but its main components are still composed of lenses, spacers (spacers), pressure rings, and lens barrels, as shown in the figure below:
At present, there are three mainstream lens positioning methods, namely snap-fit, advanced fit, advanced and snap-fit hybrid, each of which has its own characteristics and advantages, and we will flexibly use them according to different needs to ensure stable lens quality.
2. Assembly process of mobile phone lens
Assembly is the process of assembling the processed lenses, spacers, pressure rings and other parts one by one in order to achieve optical performance.
The assembly of the mobile phone lens first requires the arrangement of the lens barrel, and then according to the technical requirements of the drawings, the assembly of the lens, shading sheet, spacer, pressure ring and other parts is carried out according to a certain assembly sequence (among them, the assembly of the lens and the pressure ring generally requires a press-in process), and finally the glue is coated and exposed, and sent to the subsequent appearance and performance inspection.
The assembly sequence of the components is shown in the figure below;
After years of development, the manufacturing process of mobile phone lens has undergone tremendous changes. At present, it has basically entered the era of automatic assembly and processing. At present, there are two main types of assembly methods, multi-station and total-station.
Working principle and advantages: According to the actual product needs, the user can define the assembly process parameters, automatically identify the center of the lens through the image, and accurately move the robot arm and sliding mechanism to the established coordinates to complete the lens assembly, quickly and easily complete the verification of lens quality, and improve assembly efficiency.
3. Technical elements of lens assembly
The assembly process seems simple, but the technical points are very complicated. It takes years of technical accumulation and continuous exploration and improvement to manufacture a qualified high-pixel lens.
As a high-precision civilian product, mobile phone lenses have strict standards and specifications for component processing accuracy, assembly accuracy, and governance; at the same time, ultra-high-precision processing and testing equipment is required; a team of experts with rich experience and deep knowledge is also required.
Matching accuracy: The alignment of the optical axes of each lens is determined by the coaxiality and the matching state.
Assembly eccentricity: the coaxiality error between the lens and the lens barrel is the assembly.
Lens gap: In the assembly of mobile phone lenses, the distance between lenses is strictly controlled.
4. Lens Assembly Evaluation Method
The assembly process and elements of the lens are introduced above, so how to evaluate a qualified lens? There are many methods, including resolving power evaluation, transmission off-core detection, field curvature analysis, etc. Here is a brief introduction to the more commonly used defocus analysis. Through the following defocus data, the quality of a lens can be analyzed quickly and effectively, and the reason can be analyzed according to its graphic form.
5. Analysis of poor performance of mobile phone lens
There are many kinds of poor lens assembly, and the reasons are also intricate. But no matter what kind of reasons (tilt, stress deformation, looseness, substandard gap) will lead to the deviation of the actual optical system parameters and theoretical parameters, field curvature, local image blurring, and even the full field of view blurring of some sensitive systems; at the same time, other optical parameters may also change.
Common adverse phenomena and their causes are as follows:
1. Black screen:
The sensor is poorly welded, poorly bonded, the FPC line is broken, and the connector is damaged;
2. Huaping:
Sensor cracks, bad patch, thin FPC and poor contact;
3. Fuzzy:
The focus is not in place, the lens is polluted/damaged, and the focal length of the lens is changed under pressure;
4. Unable to adjust focus
Poor welding of the motor, short circuit of the solder joints, damage to the driver IC, stuck lens, and structural interference;
5. Reddish, blue:
The difference between batches of chips is bad, and software debugging can solve it.
In short, a good lens requires not only excellent design capabilities, but also advanced manufacturing capabilities, sophisticated testing and manufacturing equipment, and strict control capabilities. Each of these is indispensable, which is why there are only a handful of optical companies with high-pixel R&D and manufacturing.