Detailed explanation of VCM dispensing process of camera module

April 9, 2022

Latest company news about Detailed explanation of VCM dispensing process of camera module

Detailed explanation of VCM dispensing process of camera module

1. The background of VCM

Technology promotes social progress, and consumer electronic products are also rapidly evolving in accordance with the general trend of thinner, lighter and higher performance. The camera function of mobile phones, from scratch, from hundreds of thousands to 100 million pixels, from smearing, aliasing to fine color and picture quality, has also achieved a huge leap in function. As the hardware support of the camera function, the performance, structure and volume of the mobile phone camera have become the core factors restricting the camera function and one of the important indicators to consider the performance of the smartphone.

Since Sharp first launched a camera phone in 2000, the camera of the mobile phone has changed from no focus, anti-shake, zoom, beauty to the current auto focus, multi-camera, and 3D functions. After more than 20 years of development, the camera structure has finally been finalized and widely used.

2. What is VCM?

VCM (Voice Coil Moto), commonly known as voice coil motor or voice coil motor, has become the most widely used autofocus camera module. Its function is to drive the movement of the shrapnel/spring by controlling the current, and adjust the position of the lens in the three axes of XYZ, so that the focused object presents the clearest state. It has the advantages of small size, high precision, good integration, high reliability, and can support high power, which significantly reduces the size and volume of the finished product and reduces the cost of the whole machine.

3. The structure of VCM

Generally speaking, VCM consists of the following parts:

FPC: used to connect the motherboard and the camera module;

Bottom case back cover: generally in-mold injection process, used to link FPC;

CMOS image sensor: Now it is generally a CMOS sensor;

Lens group: generally composed of multiple lenses, which are fixed by an injection-molded shell and glued to form a fixed lens group;

Magnet/coil: used to drive the electromagnetic movement of the motor;

Lower conductive cover: fix the coil and carry the surrounding magnets;

Front locking piece: lock and carry the Bonding shrapnel;

Metal shell: cover the entire VCM module and electromagnetic shielding.

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4. the principle of VCM

VCM mainly uses gravitational or repulsive force to push the lens, moving it by means of reeds to support the lens expansion and contraction, giving the coil different currents to make the lens stop at different points.

The VCM of the mobile phone camera needs to cooperate with the driver chip to complete the focusing. The driver IC controls the size of the VCM power supply current to determine the moving distance of the lens mounted on the VCM, so as to adjust to the appropriate position to capture a clear image. 

5. VCM dispensing position

In order to pursue thinness, the smallest volume, and meet the requirements of extremely thin and light mobile phones, most VCMs are designed with less or no screws. Adjacent structural parts are glued together with glue, except for a small amount of direct threads. In order to accommodate more functions and mechanical components in a limited design space, and to achieve the use strength of earthquake resistance and anti-fall.

The following picture shows the dispensing position of the VCM device:

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6. Difficulties in VCM dispensing

1. Small components and precise components;

2. The dispensing accuracy is required to be high, and the dispensing position is narrow (for example, the width of the narrow edge is less than 0.3mm);

3. There are many dispensing positions;

4. The glue is mostly viscous black thermosetting glue, conductive glue, solder paste, damping glue and other glues with larger resistance and larger particles;

5. Scattering, overflowing, and irregular outer diameter of the glue caused by the characteristics of the glue;

6. The glue curing method is oven curing, the temperature is 96°~128°, and the curing time is 10min~20min.


7. Actual dispensing case

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