Mobile camera module dispensing analysis

The dispensing process is a key link in the assembly of camera modules, playing a crucial role in the performance and reliability of the module. This article will detail the dispensing process of mobile camera modules, exploring aspects such as the background of dispensing, selection of dispensing materials, the dispensing process, challenges in dispensing, and solutions.

The core components of mobile camera modules mainly include CCD and CMOS sensors, which determine the resolution and imaging quality of the camera. In practical applications, these precision components need to be bonded and fixed using the dispensing process to ensure their stability and reliability. The dispensing process not only enables a tight connection between components but also enhances the overall shock resistance and drop resistance of the module.

When selecting dispensing materials, multiple factors need to be considered. Firstly, there are various curing methods for adhesives, such as UV curing and thermal curing. UV curing adhesives cure quickly, suitable for situations with high requirements for curing time; while thermal curing adhesives have advantages such as controllable curing temperature and high curing strength. Secondly, different bonding points require different types of adhesives. For example, the bonding of the lens to the lens holder requires adhesives with low shrinkage, low stress, no leakage, and fast curing; while the bonding of the filter to the lens base requires adhesives that can cure at low temperatures and bond glass to plastic. Additionally, the reliability, stability, and high-temperature and high-humidity resistance of the adhesive also need to be considered.

The dispensing process is usually arranged in the middle stage of the camera module assembly. In a clean room, operators use precision dispensing equipment to evenly apply specific adhesives to designated bonding points. Before dispensing, tasks such as adhesive selection, equipment debugging, and path planning need to be performed. During adhesive selection, suitable adhesives must be chosen based on factors such as the product's operating temperature range and the material and requirements of the bonding points. During equipment debugging, parameters such as the diameter of the dispensing needle and air pressure need to be adjusted to ensure that the width and error of the adhesive line meet the requirements. For path planning, three-dimensional simulation software is typically used to draw the adhesive application trajectory to avoid bubbles and adhesive breakage.

In practical operations, the dispensing process has strict requirements for the temperature and humidity of the environment. The workshop temperature must be stable at 23±1℃, and the humidity must be maintained below 45% RH. This is because changes in environmental temperature and humidity can affect the flow rate and curing effect of the adhesive, thereby impacting the performance and reliability of the module. For example, when the environmental temperature fluctuates by more than 2℃, the change in adhesive flow rate can lead to a 12% decrease in yield. Therefore, it is necessary to strictly control the environmental temperature and humidity during the dispensing process.

There are several challenges in the dispensing process of mobile camera modules. Firstly, the internal structure of the module is complex and precise, with many dispensing locations and high accuracy requirements. Roughly estimated, there are about 30 adhesive points inside the module, each of which requires precise control of the adhesive amount and curing effect. Secondly, the materials that need to be bonded inside the module are diverse, including LCP, PET, PC, PBT, PA, FR4, ceramics, and glass. Different materials require different types of adhesives, and the performance requirements for the adhesives also vary. Additionally, the usage requirements and purposes of different bonding points are also different, such as the bonding of the lens to the lens holder requiring low shrinkage and low stress; the bonding of the filter requiring low-temperature curing and the ability to bond glass to plastic.

In response to these challenges, the industry has proposed a series of solutions. Firstly, using non-contact jet dispensing valves for dispensing can avoid issues of component damage and defect rates caused by contact dispensing. Non-contact jet dispensing valves have advantages such as uniform dispensing, high efficiency, and high precision, making them suitable for high-precision dispensing in extremely small locations. Secondly, equipping a CCD vision assistance system can improve the accuracy and efficiency of dispensing positions. By using a million-level industrial camera for intelligent recognition of dispensing positions, it can reduce position calibration time, avoid contaminating components with leaks, and ensure repeatability requirements. Additionally, for the application of different materials and adhesives, free testing services can be provided to determine the best type of adhesive and dispensing parameters through practical testing.