We have heard many times about liquid lenses, which is a new type of technology that allows the cameras of our smartphones to get to performance never seen before. The first time we heard this term was with the Huawei P50 but Xiaomi foretold that his new Mi MIX series device will be equipped with this particular technology. However there are still gray areas and poco you know about them. Let's try to clarify.
Everything you need to know about liquid lenses in smartphone cameras: what they are, how they work and what changes from before
Before understanding what liquid lenses are and how they work, it is necessary to approach some technical concepts and physical phenomena. The first is the phenomenon of surface tension. Think of a drop of water on any surface: it can happen, for various reasons that we will not list here, that this drop remains round and does not "split". It almost looks like a film has been placed around the drop itself. Here, that's a surface tension phenomenon.
In a nutshell it happens that the molecules of the fluid undergo the attraction of the neighboring molecules and this causes the phenomenon known as surface tension. Clearly the intensity of this voltage depends on the type of liquid and on the adjacent material (in the case of the photo, respectively, water and leaf)
The second concept that needs to be addressed is that ofcontact angle. When the aforementioned drop touches the surface, it does not wet it in its entirety but the area it will touch will vary as the contact angle changes. To understand the concept well, see the photo below.
Related to the concept of wettable surface and of contact angle there is also that of hydrophobia but here we don't care that much. By modifying the curvature we are able to modify the focal characteristic that distinguishes this new lens technology. Mainly to do this we have two methods: theelectrowetting , pressure variation.
Electrowetting is an operation that was born in the early 2000s in France. We need to know that they are present inside the lens two liquids that hardly mix, a bit like water and oil. If these liquids come electronically stimulated then they move, varying their curvature at the same time (think of the lens of the human eye). We will immediately understand the convenience of this operation: no analog movement is needed to focus, but the electric impulse is enough. Below is a video showing us the principle behind electrowetting.
The second way to change the curvature of this type of lens, as anticipated, is the pressure. In general, there are two types of lenses in this context: lpressure units with hydraulic pump e polymer lenses. In first the case when a piezoelectric pump applies pressure to the liquid, the surface tension of the liquid can be manipulated; in according to the case a thin membrane builds
the interface between two chambers each containing a different material and the pressure difference between them
two chambers defines the deflection of the membrane and thus one changes the curvature.
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In general we can say that this kind of lenses guarantees not only one more easy usability as less "complex" to handle, but also one better quality since the liquids inside bring the overall structure closer to that of the human eye. Technically they are not too new methods: scanner readers or webcams of different brands already use liquid lenses. However such a thing had never been seen on a smartphone.
As always, Xiaomi it moves ahead of other companies and manages to integrate a technology still unknown in the smartphone landscape.
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Source | IOP Science
