What is the use of liquid lens? How much does it improve the phone’s image capability?
On the evening of March 30, Xiaomi launched its first foldable flagship, the Mi Mix Fold, at the Spring New Product Launch. After two years, the Xiaomi MIX series is back, with Xiaomi’s self-researched professional image sensor Surge C1, as well as the world’s first liquid lens, Mi Mix Fold has attracted the continued attention of many industry insiders and Media.
So, there are many consumers curious, what is the use of liquid lens? How much does it improve the phone’s image capability? Today, the official Xiaomi for this liquid lens released detailed science.
Did you know that the optical fluid in the Xiaomi Mi MIX FOLD liquid lens has a lower refractive index and dispersion characteristics than the fluorite commonly used in SLR lenses, with excellent optical performance? It is also because of the fluidity of the optical fluid, by squeezing the liquid lens to change the optical focal length to achieve the two functions of telephoto + macro.
How does Xiaomi’s Liquid Lens achieve telephoto + macro two functions with one lens?
The lens material in a traditional solid lens is composed of glass, optical plastic, etc., and the radius of curvature is fixed after processing and forming. By driving the lens module on a motor, the focus position is changed by moving in the optical axial direction to achieve continuous focus from far-field to near-field.
However, solid lenses have a problem that has been difficult to solve so far, when the whole group of lens modules moves to achieve macro imaging, the stroke movement increases, especially telephoto lenses require a large amount of movement in super close up imaging. To ensure the thickness of the whole machine, the current demand for solid-state module size and motor stroke design limitations is difficult to achieve.
Besides, existing macro shooting in addition to telephoto macro, macro shooting is generally achieved through digital cropping and post-amplification, which has the disadvantage of low resolution and poor image quality rendering, while the design of the liquid lens makes it possible to greatly improve the magnification as well as the image quality effect while ensuring the module size.
How does the liquid lens focus?
Xiaomi Mi Mix Fold first cell phone with liquid lens, based on the principle of bionics, in the traditional solid lens with a liquid component lens with the same liquidity as the lens of the human eye, by squeezing the liquid lens can continuously change its light focal length, to achieve continuous focus from the far to the near field.
This focusing method greatly reduces the requirement for motor drive stroke and enables optical imaging at a distance of 3cm to achieve macro photography with background bokeh close to the SLR view. The 8 megapixel’s 3X liquid lens module currently used in the Xiaomi Mi MIX FOLD can reach 12.25x magnification on the screen image, while combined with digital zoom, it can achieve higher magnification macro imaging.
Besides, the liquid lens also reduces the FOV change from telephoto to close-up, and there is almost no breathing effect during the zoom from telephoto to general close-up, making it more suitable for video shooting.
The liquid lens optical performance loss?
The optical fluid in the liquid lens is a fluorinated polymer-based inert fluid (PFPE), which can maintain good luminescence performance in both low and high-temperature environments. At the same time, the processing specifications of nano-level high-precision structural components ensure the required accuracy of the liquid surface, thus achieving high-quality optical imaging.
Also, the optical fluid in the liquid lens has the nature of ultra-low refractive index ultra-low dispersion, which is even lower than the fluorite used in SLR super-telephoto, greatly reducing the chromatic aberration changes during focusing. Although the curvature change will increase the field curvature of the edge field of view, but the optical focal length change to a certain extent reduces the spherical aberration change in the focusing process so that the MTF value of the near center field of view can be maintained at a high level, to achieve a sharp center edge blurring bokeh effect.
Xiaomi officials say that this is the first time liquid lens technology has been applied to cell phone cameras, is Xiaomi MIX FOLD in macro shooting a breakthrough, but also for Xiaomi to explore the world of infinite possibilities, look forward to the follow-up will have more models equipped with the technology.