If you often use mobile phone cameras, don’t say you don’t know these principles and packaging methods.

A mobile phone camera is a shooting device on a mobile phone that can shoot still pictures or short videos. It is also an additional function of the mobile phone. The mobile phone camera module is composed of PCB board, FPC, lens, lens holder, holder, color filter, sensor and other components. When all components are packaged together, it becomes a camera component that can be directly applied to smartphones.

The working principle of the mobile phone camera module: the scene is captured through the lens, and the generated optical image is projected onto the sensor. The optical image is then converted into an electrical signal. The electrical signal is then converted into a digital signal through analog-to-digital conversion, and the digital signal is processed by DSP. , and then sent to the mobile phone processor for processing, and finally converted into images that can be seen on the mobile phone screen.

There are two packaging modes for mobile phone camera modules: COB (ChipOnBoard) and CSP (ChipScalePackage). COB (Chip on Board) means that the photosensitive chip is bonded to the substrate through gold wire, and then the lens and bracket (or motor) are bonded to On the substrate, the CSP (ChipScalePackage), which is the photosensitive chip, is welded to the substrate through SMT, and then the lens and bracket (or motor) are bonded to the substrate. Although both are used as two packaging modes, they have different advantages and disadvantages in mobile phone camera module applications.

Advantages of COB packaging: COB packaging involves multiple assembly and packaging tests of image sensors, lenses, lens holders, optical filters, motors, circuit boards, front and rear covers and other spare parts, and can be directly handed over to the assembly factory. It also has higher image quality. It has the advantages of good performance, low packaging cost and low module height, effectively saving space.

Disadvantages of COB packaging: The disadvantages of COB packaging are that it is prone to contamination during the production process, has high environmental requirements, high cost of process equipment, large yield changes, long process time, and inability to repair, etc., and if used in camera modules, it will In the drop test, it is easy for particles to shake out. The production process is shortened, but this also means that the technical difficulty of making modules will be greatly increased, affecting the yield performance.

The advantage of CSP packaging is that the packaging section is completed by the front-end process, and because the CSP packaged chip is covered with glass, it has lower cleanliness requirements, better yield, low cost of process equipment, and short process time.

Disadvantages of CSP packaging: poor light transmittance, higher price, higher height, backlight penetration ghosting phenomenon.

In fact, the biggest difference between CSP and COB is that the photosensitive surface of the CSP package chip is protected by a layer of glass, while COB is not and is equivalent to a bare chip. Compared with CSP packaging, COB packaging has many advantages, especially in reducing the height of the camera module. As smart terminals generally pursue ultra-thinness, major module manufacturers have chosen COB packaging. However, because COB packaging has very high requirements for dust-free environment, the current product yield is very low. Therefore, in order to ensure yield, a considerable number of domestic manufacturers still use CSP packaging technology, and many companies use both technologies at the same time.