Technology, Process and Cost

Liquid Lens Camera Module in the Xiaomi Mi MIX FOLD

By Yole SystemPlus — Oct 2021

Deep technical and cost analysis of the first-ever liquid lens in a consumer product.

Tunable lens technology promises to revolutionize the way smartphones achieve zoom. Conventionally, smartphone cameras simulate zoom by employing multiple modules that are each optimized for different focusing distances. Then, image-processing algorithms blend the information captured by these modules to create a sharp photograph. Tunable lenses would allow a single camera module to vary its focusing distance, which not only achieves a true optical zoom but also reduces the number of modules necessary. Xiaomi has partnered with OFILM and NEXTLENS to bring the first smartphone tunable lens to market. NEXTLENS is a spinoff of Optotune, which specializes in tunable optics for scientific applications.
The liquid lens module is comprised of a transparent fluid wrapped in a deformable membrane that can be shaped by a voice coil motor system. By working in tandem with conventional fixed lenses, the liquid lens camera module is capable of focusing distances between 3 cm – 8 cm. It can therefore achieve a 2.7x optical zoom and perform double duty as both a macro and telephoto camera module, all while coming in at a cost comparable to typical telephoto modules found in Samsung and Apple flagships.
This report presents optical, X-ray and SEM imaging, and EDX and FTIR chemical analysis used to analyze the liquid lens and the entire liquid lens camera module in the Xiaomi Mi MIX FOLD. We analyze each major system in the module, including the liquid lens, the fixed optics, the voice coil motor, and the CMOS image sensor (CIS).
Cross-sectional analysis reveals the structures of each component and how they fit together to achieve the tunable camera module. Delayering analysis allows us to determine the processes and technology node of the CIS, while chemical analysis identifies the materials used in the liquid lens and infrared filter.
This information is used to determine the manufacturing processes of the liquid lens and CIS, which are presented in this report. We then calculate the cost of each step and present itemized manufacturing and BoM costs that cover every major system and use this to estimate the selling price of the camera module.