Liquid lens, the world premiere of the new generation of Mi MIX!
This is a magical innovation, just like the “human eye lens” is installed in the lens of a mobile phone. The flowable liquid is wrapped by a film, replacing the traditional optical lens, and realizing the change of focal length and focus.
In this way, a lens can be microscopic at close distance and can be telephoto at far.

Related interests, the employees of the only domestic company that independently develops and produces liquid lenses are now commercializing two liquid lenses, one is company o in Switzerland, the other is company v in France, and company v was acquired by Corning. The company o uses film. Liquid lens, which is similar to a lens, is driven by a magnet or a motor, and the film is loosened to change the radius of curvature, thereby changing the focal length. Company v uses two liquids and uses electrowetting. Due to the difference in refractive index, the interface also has A meniscus that changes the focal length after the meniscus is deformed. In addition, there are liquid crystal lenses and a liquid lens driven by a micro-motor from Texas Instruments. Let’s take up the pit first, and then let’s start with the two-liquid lens for detailed explanation of each technology, because the current main product is a two-liquid lens. First of all, in principle, our purpose is to achieve focal length change. Therefore, if you have studied optics in junior high school, It is known that light will be refracted after entering different media, such as the common chopsticks inserted into the water cup, which seems to be bent: then we need to change the focal length, first of all refraction occurs, so the light must enter another medium from the air. Moreover, it must be ensured that the light can come out after entering, so the medium must have a higher transmittance. A two-liquid lens is composed of two liquids, and there is a difference in refractive index between them, so the interface can be refracted. In addition, it is the principle of electrowetting: Lippmann discovered in 1876. He discovered that the surface tension of the droplet will change by applying a voltage on the droplet and on the surface in contact with the droplet. The famous Young’s formula Here: The first COSθ0 is their wetting angle, that is, the angle between two different liquids, which is affected by surface tension and is also related to surface energy; the latter is the dielectric constant of air and dielectric layer dielectric. Constant; the dielectric constant of the dielectric layer is because the founder of V company, Berg discovered that after adding a dielectric insulating layer at the bottom, it can stabilize the change of the liquid and reduce the voltage; γ is the interfacial tension, and d is the dielectric The layer thickness, v is the voltage level. After the above formula is understood, the principle of the two-liquid lens is basically understood: by applying a voltage, the interface between the two liquids is changed. Due to the refractive index difference, the focal length of the liquid lens is changed: o Company’s will update it later.


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8 months ago

Interest-related. Since 16 years, the relevant application research of liquid lens has been researched. The doctoral topic is “Research on the high-precision and large-depth three-dimensional imaging technology of focal plane modulation”. The principle and advantages of liquid lenses will not be introduced too much. Unlike the current Mix that uses liquid lenses to achieve two-dimensional imaging functions (ie zoom, autofocus, macro, blur, full-definition, etc.), my subject is a three-dimensional imaging technology based on electronic focus lenses, which is mainly solved The problem is that the three-dimensional imaging accuracy, speed and depth range under the limited space-time bandwidth product are mutually restricted, and the performance has been improved several times compared with the traditional method. The characteristics of the liquid lens in the three-dimensional imaging application in the paper are summarized as follows: 1. Optotune’s EL-10-30 step response speed is about 15ms, and the drive current needs to be optimized for less than 10ms; 2. In a certain environment (temperature and humidity) and Under the geometric position, the zoom uncertainty of the liquid lens is less than 0.005%; 3. The coma caused by temperature and gravity still has a significant impact on the Optotune lens, which still needs to be improved in the future. Now I am very happy to see that Xiaomi can release a new MIX machine equipped with a liquid lens. First, I am pleased with the independent innovation of domestic manufacturers. Second, I can carry out related research five years earlier than the industry, which is regarded as a relief to my doctoral career.

8 months ago

First of all, let’s clarify why we need to develop a liquid lens. Secondly, let’s talk about the classification of liquid zoom lenses again, and then talk about the zoom principle of the double liquid lens based on the principle of electrowetting. Finally, let’s talk about the classification of current commercial liquid zoom lenses. References: Non-industry professionals, simply searched a bit of information, and shared with you. If there are any errors, you are welcome to come to correct me. First of all, let’s clarify why we need to develop liquid lenses. Because the autofocus of a mobile phone lens is different from that of a digital camera, it cannot adjust the optics. At present, the focusing methods of mobile phone lenses are mainly divided into three types: laser focusing, phase focusing and contrast focusing, and they have the disadvantages of high energy consumption, complex structure, and relatively low lifespan. These shortcomings can be effectively avoided by adding a group of liquid lenses to the optical lens group. Liquid zoom technology, as a new type of zooming method, realizes the adjustment of focal length by changing the shape or refractive index of the liquid lens. The liquid zoom lens does not require a complicated mechanical zoom structure, and has the characteristics of small size, fast response, low cost and high integration, which greatly simplifies the structure of the optical imaging system, and is conducive to the miniaturization and lightweight of integrated equipment. Secondly, let’s talk about the classification of liquid zoom lenses according to the different liquid zoom drive mechanisms. Liquid zoom lenses are divided into physical property control type and mechanical drive type, as shown in Figure 1 below. Classification of liquid zoom lenses Among them, physical property control zoom lenses include liquid lenses based on liquid crystal materials, electrochemical activation, dielectrophoresis technology, and electrowetting technology. Mechanically driven zoom lenses include liquid zoom lenses based on electrostatic force drive, electromagnetic force drive, pressure adjustment, and environmental response. At present, the current two-liquid lens based on the electrowetting principle is the mainstream direction of the current liquid lens development. Again, let’s talk about the zoom principle of the two-liquid lens based on the electrowetting principle. First, let’s explain the basic principle of the electrowetting technology. Electrowettong on dielectric (EWOD) technology is currently a technology widely used in liquid lens manufacturing. By applying a voltage between the electrode and the conductive liquid, the surface tension between the conductive liquid and the insulating layer is changed, so that the contact angle between the two is changed. The principle is shown in Figure 2. Figure 2 Schematic diagram of electrowetting. The dual-liquid lens uses two immiscible liquids combined to form a meniscus lens. One liquid is an electrolyte, such as an aqueous solution; the other liquid is an insulating solution, such as a non-polar oil. A voltage is applied between the aqueous solution and the metal electrode. When a voltage is applied from the outside, the liquid level of the aqueous solution around the container rises, and the oil fills the space vacated by the aqueous solution in the middle, thereby changing the arc between the two liquids. Finally achieve the purpose of changing the focal length of the lens and realizing automatic zooming. The principle of automatic zooming of electrowetting lens and the automatic zooming of lens based on electrowetting liquid have the following characteristics: no mechanical structure, the volume can be controlled in a small range; power <1 mW; the convex or concave surface of the lens is made of liquid-liquid The interface is formed, so it can spontaneously form a lens with high surface quality; the driving voltage is relatively high, generally ≥30 V. There is a question here: it is generally difficult to provide a voltage above 30V on mobile phones. If Xiaomi uses a double liquid lens, I don’t know how Xiaomi solves the problem of driving voltage. Finally, let’s talk about the classification of current commercial liquid zoom lenses. At present, commercial liquid zoom lenses can be divided into two types: gradient index lenses and variable curvature lenses. The focal length is adjusted by controlling the alignment of the liquid crystal material and the curvature of the liquid interface. The LV-S3 series gradient index lens produced by LENSVECTOR, USA, uses a dynamically adjustable electric field to change the orientation of liquid crystal molecules to adjust the refractive index of the lens. The Arctic316 electrowetting zoom lens developed by France VARIOPTIC and the APL1050 variable curvature liquid lens produced by HOLOCHIP in the United States can adjust the focal length by changing the voltage or filling the liquid pressure, respectively. After understanding the mainstream commercial liquid zoom lens, if we can know the supplier of the liquid lens, we can also reverse the principle of Xiaomi liquid lens. Waiting for Xiaomi’s follow-up update, continue to look forward to it.

8 months ago

Lomography LomoMod No.1 is a toy medium format camera assembled from cardboard. It is equipped with a liquid lens (Sutton lens) and uses 120 film. It is worth mentioning that this lens does rely on the liquid injected into it to provide refractive power, not just treat the liquid as a layer of “filter” or something. When the user buys this camera, the package box he bought contains a pile of pre-cut cardboard and lens housing (because the “lens” of this lens is actually the liquid itself injected into the lens during use, so the other parts are shell). The user needs to assemble them into a camera according to the instructions, then inject the liquid, load the film, and then shoot.

8 months ago

As long as Xiaomi uses this technology, it should show that the technology is relatively mature, but the cost is higher, so it will be applied to the MIX model. If the effect is good and the price is low, I hope that it will be down to the ordinary digital series as soon as possible. Liquid lens was born mainly to solve the zoom bottleneck of traditional lens. The advantage of liquid lens The reason why the traditional zoom method “goes to the end” is because multiple fixed lenses have to be pushed back and forth. If the lens does not move, but can change the arc by itself, and then change the light path, then the zoom problem will not be solved. ? In fact, the principle of liquid lens is not complicated. It entered our eyes earlier than traditional lenses. The reason why the human eye can adjust the focus seamlessly is because the ciliary muscle is automatically adjusting the curvature of the lens. The cause of myopia is also the spasm caused by the long-term contraction of the ciliary muscles, and the muscles cannot relax normally and see the distance clearly.

8 months ago

Electro-wetting on dielectric technology (EWOD) for zoom lenses based on electro-wetting technology is currently one of the most widely used technologies for manufacturing liquid lenses. This technology changes the wettability of the droplet and its contact surface by applying a voltage between the liquid and the electrode, so that the contact angle between the droplet and the surface of the medium changes. The principle is shown in (a). The relationship between the change of the contact angle of the droplet and the applied voltage U. According to the equation, the change of the cosine cos θ of the contact angle between the droplet and the medium is not only related to the change of the voltage value, but also affected by the thickness of the dielectric layer d and the dielectric constant. The effect of ε changes. (B) shows the change of the droplet contact angle before and after pressurization. It can be seen that when a voltage is applied, the droplet deforms causing the contact angle to decrease. Principle and experiment of electrowetting. (a) Schematic diagram of electrowetting principle on the medium; (b) Droplet wettability experiment before and after pressurization. Wang Qionghua of Sichuan University and others designed an optical microlens based on the ring aperture and center aperture focusing mode, the structure is as (a ) Shown. The device uses polarizers and liquid crystal materials to control the on and off of incident light in different polarization directions. (b) and (c) show the path of incident light in the lens in the initial state and the liquid crystal material applied voltage state, respectively. In the ring aperture mode, the incident light power is increased by 3 times due to the effect of the reflector to enhance the imaging brightness of the lens; in the center aperture mode, the edge light is blocked, thereby reducing aberrations and expanding the depth of field. Improve the optical imaging quality of the lens. The relationship between lens focal length and voltage in different modes is shown in Figure 6(d). When the driving voltage is changed from 20 V to 70 V, the focusing range of the center aperture mode lens is (-∞, -66.7 mm)∪(+32.4 mm, +∞). The ring aperture mode lens can only focus, and the focus range is (+18.4 mm, +∞). Compared with the traditional electrowetting lens, this type of liquid lens can switch between the annular aperture mode with high resolution and high optical power and the annular aperture mode with large depth of field and small aberration. However, due to the reduction of the effective aperture and With the function of the polarizer, the optical efficiency of the lens is reduced, and the driving voltage is still high.

8 months ago

Xiaomi is awesome, and the mix series dominates the development of mobile phones. The previous full-screen display is quite shocking. Now the full-screen display is full of all kinds. Now the liquid lens replaces the traditional optical lens, and the image is even more advanced. , The science and technology industry needs such innovative spirit. Apple hastened to buy a cemetery and bury itself.

8 months ago

Although I would like to say that Xiaomi is beautiful, but from a practical point of view, the liquid lens is not very large, because the main camera is not improved. For various objective reasons, the lens of the non-telephoto part of the mobile phone is heavily dependent on the double-sided aspheric lens. The liquid lens has not yet been mature and mass-produced as an example of double-sided aspherics, so this time it is only to improve the close-up ability of the telephoto part. The application scene itself is very narrow, but it is good to make it. Look forward to it.

8 months ago

If rice can be made, the key point is self-research. That is worth talking about, indicating that Xiaomi has also begun to pay attention to research and development, as long as Xiaomi pays attention to research and development, then there is nothing to say. Xiaomi is awesome. But because of Xiaomi’s consistent style, this estimate is just a hot spot, or selling point. I am not optimistic about this technology. I neither think how mature it will be, nor do I think it will produce energy. It’s not that you look down on Xiaomi. But this technology is not accidental and is the same as the original intention of the periscope camera. What is done is to complete all the scenes with one lens. The periscope is still a mechanical structure, and the final effect is just like that. How can people expect a liquid lens? Not to mention the impact of various harsh conditions on liquids. So this technology, how can I say, I think Xiaomi is the first to do it as a mobile phone manufacturer, and it may only be done by Xiaomi in the end. However, as long as Xiaomi is willing to die and let me see the second generation of liquid lens next year, I will not mind blowing it up. At present, I can only wait and see. After all, there are too many examples of Xiaomi losing it after one bite. Every time it is a hot spot, the whole network blows up, and then there is no more information.

8 months ago

Let’s talk about the meaning of the Xiaomi MIX series. For Xiaomi, the meaning behind this series is greater than the sales of the product itself. (Part of the following information comes from unpredictable: Xiaomi’s 10th anniversary) In the fourth quarter of 2016, Xiaomi’s shipments showed a sharp decline. IDC’s 2016 China Mobile Phone Market Quarterly Tracking Report showed that Xiaomi’s sales showed a sharp decline, mainly due to mobile phones. , The supply chain remedial course has just started, and the problem of Snapdragon 810 has not been completely solved. The orders for Qualcomm chips are not scheduled, and the supply problem of Xiaomi is very serious, and many products are still in a state of severe shortage. According to the annual market share estimation, at this time Xiaomi has fallen out of the top five positions in the world and belongs to the ranks of Others. Therefore, Lei Jun decided to make money regardless of commercial costs, not driven by commercial purposes, so that all innovative spirits can be brought to the extreme, which he regarded as a venture capital product. This is the MIX series that is the first mobile phone in the world, allowing the screen ratio of the mobile phone to reach more than 90% for the first time, and completely changing the shape of the mobile phone. The full-screen design of the first generation of Xiaomi’s MIX has promoted the development of the entire mobile phone screen industry to full-screen, allowing many screen industries and technologies to be applied on the consumer side. Mi MIX is the world’s first full-screen mobile phone, half a year earlier than Samsung’s full-screen mobile phone, and a year earlier than Apple’s. Xiaomi MIX Alpha surround screen, which is also a common sense based on the screen orientation, but unfortunately the surround screen technology is too difficult, and the current application scenarios are also relatively limited, so there is no mass production in the end. Subsequently, after a few years, after Xiaomi’s sales grew steadily, the Xiaomi MIX series slowly faded out of sight, and the MIX flagship mobile phone lost its groundbreaking advantage and influence. However, Xiaomi obviously will not give up this series. This time the Mi MIX series has changed its direction and started a major industry breakthrough for mobile phone cameras. This is actually a good thing. If industrial technology can be applied to the consumer end, it will be important for the entire industry. The driving force is still very strong. Moreover, as for the liquid lens, this is a simple principle. The liquid spherical refraction and reverse principle plus the focal length change after the curved surface change, but the industrial design is difficult. This time, let’s take a look at the actual consumer and commercial possibilities of the liquid lens of the Mi MIX series. How big and how big is the consumption threshold.

8 months ago

Someone must jump out again and say that it’s not self-study. I want to laugh to death. It’s better than Apple. At least the screen and camera are all from other homes, but nobody jumps out and stares at these useless things every day. Just read more books and improve. Now that teamwork is the mainstream, so-called teamwork is to maximize the strengths of each part. The important thing is whether the final product is good or not, not a mobile phone assembled by a few people in the team, you can say that it is better than assembly line assembly. Is it good? On the contrary, it is inefficient and not good. Of course, I also think that the core technology should be mastered, but young companies definitely need time.

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