Basic composition of camera module

Lens, lens base, infrared filter (IR), photosensitive chip (sensor), DSP/ISP (signal processor), PCB/FPC (printed circuit board/flexible circuit board), these are the basic components that constitute a camera module. There are many internal subdivisions. Now let’s briefly introduce these basic components:

Lens is a device that can receive light signals and focus them on the photosensitive device CMOS/CCD.

Lens determines the lighting rate of the sensor, and its overall effect is compared to a convex lens. Generally, the lens structure of a camera is composed of several lenses, which are divided into plastic lenses (PLASTIC) and glass lenses (GLASS). The lens structures usually used by CAMERA are: 1P, 2P, 1G1P, 1G3P, 2G2P, 4G, 8P, etc. The more lenses, the higher the cost; glass lenses are more expensive than plastic lenses, but the imaging effect of glass lenses is better than that of plastic lenses.

It fixes the lens and is the rotating center for adjusting the focus of the lens. It rotates the lens to achieve the clearest picture within the focal length.

IR cut filter is an infrared cut filter, which is placed between the Lens and Sensor. Because the human eye and the sensor respond differently to each wavelength, the human eye cannot see infrared light but the sensor can sense it, so an IR cut filter is required to block infrared light.

There are various wavelengths of light in nature. The wavelength range of light recognized by the human eye is between 320nm-760nm. The human eye cannot see light exceeding 320nm-760nm. The camera's imaging component CCD or CMOS can see most wavelengths of light. Due to the participation of various lights, there is a color deviation between the color restored by the camera and what is seen by the naked eye. For example, green plants turn gray, red pictures turn light red, black turn purple, etc. At night, due to the filtering effect of the bimodal filter, the CCD cannot make full use of all light, does not produce snowflake noise, and its low-light performance is unsatisfactory. To solve this problem, use the IR-CUT dual filter.

IR-CUT dual filters refer to a set of filters built into the camera lens set. When the infrared sensing point outside the lens detects changes in light intensity, the built-in IR-CUT automatic switching filter can automatically switch according to the intensity of external light to achieve the best image effect. In other words, the dual filters can automatically switch filters during the day or night, so you can get the best imaging effect regardless of the day or night.

Image sensor is a semiconductor chip with millions to tens of millions of photodiodes on its surface. The photodiodes generate charges when exposed to light and convert light into electrical signals. Its function is similar to the human eye, so the performance of the sensor will directly affect the performance of the camera.

Photosensitive elements are divided into two types: CCD and CMOS.

DSP: Digital signal processor DSP (DIGITAL SIGNAL PROCESSING) function: mainly optimizes the digital image signal parameters through a series of complex mathematical algorithm operations, and transmits the processed signals to PC and other devices through USB and other interfaces;

ISP: ISP is generally used to process the output data of the Image Sensor, such as AEC (automatic exposure control), AGC (automatic gain control), AWB (automatic white balance), color correction, Lens Shading, Gamma correction, removal of bad pixels, Auto Black Level, Auto White Level and other functions.

PCB (printed circuit board), also known as printed circuit board, is one of the important components of the electronics industry.

The printed circuit board is composed of an insulating base plate, connecting wires and pads for assembling and welding electronic components. It has the dual functions of conductive lines and insulating base plates. It can replace complex wiring and realize electrical connections between components in the circuit. It not only simplifies the assembly and welding work of electronic products, reduces the wiring workload in traditional ways, and greatly reduces the labor intensity of workers; it also reduces the size of the entire machine, reduces product costs, and improves the quality and reliability of electronic equipment. Printed circuit boards have good product consistency and can adopt standardized designs, which is conducive to mechanization and automation in the production process.

Flexible Printed Circuit (FPC) is a highly reliable and excellent flexible printed circuit board made of polyimide or polyester film as the base material. It has the characteristics of high wiring density, light weight, thin thickness and good bendability.