Thanks to the advanced camera modules, taking photos and videos with your mobile phone is a like spinal reflex now.
In this post, we’re going to share the basics of a camera module with you.
1. What is camera module?
Camera module is a genuine imitation of human eye.
Basically, it consists of a lens, a holder, a voice coil motor (VCM), an infrared ray (IR) filter, a sensor and a flexible printed circuit (FPC).
Let’s debrief them so you can know better what they are:
- Lens: lens is a key part of the camera module. It’s used to generate images. The quality of lens is a crucial aspect determines the quality of image.
- Holder: a structure usually plastic used to contain all the components.
- VCM: an element embedded in the holder. It’s used to adjust the focal length of lens.
- IR filter: the range of the light wavelength that the sensor on camera can receive is larger than that on human eyes, thus an IR filter is here to filter those invisible light.
- Sensor: Another key part of the camera module. It’s used to receive the image that the lens generates.
There’re two types of sensors: CCD (charge coupled device) and CMOS (complementary metal oxide semiconductor).CCD has a better sensitivity, thus it can produce better image. However, imaging speed of CCD is quite slow, and its processing circuit will produce large heat, which results in thermal noise and energy waste.
CMOS is comparatively cheap and energy saving, and the image quality it provide is increasing gradually, making it a better choice in the market, especially in the consumer electronics area.
- FPC: it’s an integrated control circuit combined with the linkage to other parts of the device.
2. Types of camera module
Divided by the position, there are 2 types of camera modules: a front camera module and a rear camera module.
2.1 Front camera module
The front camera module is mainly used to take selfies and video calls, and normally it has only one lens. iPhone X successfully creates the new norm.
Today in high end mobile phones, the front camera can be integrated with a Time-of-Flight (TOF) camera to realize facial recognition.
Though the single front camera phones can do that too with the help of algorithm, phones using TOF camera are a lot safer and can unlock without light.
TOF camera makes many interesting functions possible. Facial expression animations and 3D model reconstruction are two vivid examples.
2.2 Rear camera module
Rear camera module is usually used to take photos of others and videos. There is always a flashlight in rear camera module.
Manufacturers has thought of a lot of ways to enhance the ability of rear camera module, such as developing better sensor, improving the optical properties of lens and adding more camera into modules.
According to the number of the camera, we can divide rear camera module into 3 types: single camera module, dual camera module and triple camera module.
2.2.1 Single camera module
It’s the traditional rear camera module in low end electronic devices.
2.2.2 Dual camera module
There are mainly three setups of dual camera module:
- Color plus color: designed to realize bokeh and refocus. It appears in some low end phones.
- Color plus monochrome: in this setup the color information and gray scale information are recorded separately, then the algorithm will combine two picture together to realize better photo quality, especially in low light scenes and nights. Huawei phones are the outstanding representatives using this scheme.
- Wide angle plus telephoto: mainly designed to achieve optical zoom. In this way we can obtain clearer photos of the scenery at long distance. It appears in high end iPhones and Samsung Galaxy series.
2.2.3 Triple camera module
Adding one more camera into dual camera module enables us to take super telephoto or super wide angle images, which bring a huge visual impact.
That’s all for what we have to say in this post.
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