What is Camera Modules?

Core Definition
A camera module is a complete functional component that converts optical images into electronic signals. It's not just a single lens or chip, but rather a packaged assembly of precision components. It's the core component that enables photo and video recording in devices like smartphones, computers, cars, and security cameras.

You can think of it as the heart and eyes of a "mini camera," responsible for all the basic tasks from "seeing" to "generating digital photos/videos."

Main Components of a Camera Module
A typical camera module typically consists of the following key components:

Lens

Function: Responsible for collecting light, acting as the camera's "eye." Typically composed of multiple lenses (plastic or glass) to correct for aberrations and focus light.

Key Parameters: Focal length, aperture (F-number).

Image Sensor

Function: This is the "heart" and "brain" of the module. It converts the light signals captured by the lens into electrical signals. It is the most critical component in determining image quality (such as resolution, noise, and dynamic range).

Types: There are two main types: CCD (charge-coupled device, primarily used in high-end professional applications) and CMOS (complementary metal oxide semiconductor, currently the dominant form in consumer electronics due to its low power consumption, low cost, and high speed).

IR filter

Function: Typically installed between the lens and the sensor. The wavelength range of light visible to the human eye is 380nm to 780nm, and sensors are also sensitive to infrared light. Failure to filter out infrared light will result in a color cast (usually a reddish tint) in captured images. The IR filter blocks infrared light and allows only visible light to pass, ensuring accurate color reproduction.

Voice coil motor

Function: Used to drive the lens and achieve focus. By varying the magnitude and direction of the current flowing through the coil, the front-to-back position of the lens is precisely controlled, ensuring a clear focus on the sensor.

Types: Open-loop motor, closed-loop motor, memory metal motor, etc., with different types offering varying focusing speeds and accuracy.

Substrate and connector

Function: Provides physical support and electrical connections for the image sensor and other electronic components. It connects to the device's mainboard via a flexible circuit board or connector, transmitting data, power, and control signals.

Base and bracket

Function: Precisely secures and packages all of the above components together, ensuring optical alignment and protecting the delicate internal components from dust, shock, and electromagnetic interference.

Camera module workflow

A simplified imaging process is as follows:

Light → Lens (focuses light) → IR filter (filters infrared light) → Image sensor (converts optical signals into electrical signals) → Internal ISP or main chip (processes the electrical signals, such as noise reduction, color correction, and compression) → Final digital image/video

Key Technical Indicators of Camera Modules
The following indicators are generally used to evaluate the quality of a camera module:

Sensor size: Usually expressed in inches (e.g., 1/1.7") or diagonal length. As the saying goes, "a bigger sensor means more," a larger sensor generally means better image quality, less noise, and improved bokeh.

Pixel size: The physical size of a single pixel, measured in microns (µm). With the same technology, larger pixels capture more light and provide better low-light performance.

Focus methods: Common ones include phase detection, contrast, and laser focus, which affect focus speed and accuracy.

Optical image stabilization: Compensates for hand shake by moving the lens or sensor, improving image quality and video stability.

Applications: Camera modules are ubiquitous, with applications including, but not limited to:

Smartphones: The largest market for camera modules, from rear-mounted multi-cameras to front-facing selfie cameras.

Automobiles: Used for backup cameras, 360-degree surround view, autonomous driving visual perception systems (ADAS), and dashcams.

Security monitoring: webcams, CCTV, etc.

Laptops/tablets: Used for video calls.

Medical equipment: endoscopes, dental cameras, etc.

Industrial inspection: Machine vision for product defect detection, dimensional measurement, barcode recognition, etc.

IoT devices: smart doorbells, drones, AR/VR devices, etc.

In short, a camera module is a highly integrated photoelectric conversion system. It's more than just a lens or a sensor; it encompasses a complex combination of optics, mechanics, electronics, and software algorithms. Every digital photo and video we see in our daily lives is first captured and converted by this tiny module.