In order to improve recognition, smartphones always like to be paired with a colored back cover. However, if you choose red, orange, yellow, green, blue, indigo, purple and other solid colors and other types of easy to "crash", so manufacturers prefer to introduce "gradient color" to bring a unique personality color.
In 2017, brands represented by OPPO and vivo realized the anodizing gradient process based on the metal body. With the unification of the glass back cover, gradient coating, gradient spraying, gradient printing, gradient impregnation and other processes have appeared, after the optimization and integration of AG process, optical texture technology and light change materials (ink, etc.), the back cover of the mobile phone has begun to move towards the 3D stereoscopic light and shadow change effect, and also derived the crystal drill process and luminous (such as realme firefly color matching) and other special designs.
However, the color-changing effects of the above designs are all "passive skills", which require the use of light and change the viewing angle to present a personalized light and shadow gradient. The color-changing effect of the electrochromic process belongs to the "active skill", which does not require light, and changes when you want to, which can create a more cool visual experience.
What is the electrochromic process
In simple terms, the so-called electrochromic change is the phenomenon of stable and reversible color changes in the optical properties of the material (EC film) (reflectivity, transmittance, absorption rate) under the action of the applied electric field. EC thin film materials undergo redox reaction under the action of electric fields, resulting in changes in the transmittance and reflectivity of light, and then achieve changes in the color or transparency of the product appearance.
The earliest record of electrochromic discoloration dates back to the 1930s, when German scientists first noticed the electrochemical coloration of tungsten oxide. The concept of electrochromic discoloration was formally proposed in the 1960s, and in 1969, an electrochromic device was made using WO3 thin film (a color-changing material).
Before smart phones, electrochromic process is mainly used in the field of architecture and transportation, such as some high-end hotels will use electrochromic-based smart windows, which can control the light intensity of the incoming room by changing their own color, which can not only protect privacy in real time but also bring warm winter and cool summer effects. For example, many aircraft have long eliminated mechanical sun visors, and replaced them with portholes based on electrochromic materials, which can manually or automatically adjust the shade of window color to achieve the effect of shading.
In addition, the electrochromic process has also appeared in many cars, some anti-glare rearview mirrors use electrochromic technology to automatically change color to reduce reflectivity, and some new electric vehicles also use electrochromic materials as interior decoration to enhance the sense of technology.
Electrochromic discoloration is married to mobile phones
Although the electrochromic process has a long history, whether it is a building, an airplane or a glass or interior on a car, it has no sense of the thickness parameter, and when it encounters a smart phone with "bone feeling as beauty", it will inevitably appear the phenomenon of "water and soil dissatisfaction".
The reason is simple, electrochromic glass in order to achieve a discoloration effect requires the use of multi-layer structure. Smartphone lens glass (including the back cover) is a highly integrated, extremely sensitive optical component, if the glass is too thick will make the camera module more convex, but also affect the transmittance and lead to image color casts. Therefore, in order to marry the mobile phone (lens or glass back cover), electrochromic change requires special customization optimization of the process, that is, to be lighter and thinner, higher light transmittance, and faster reaction (color change) speed.
At present, electrochromic materials have undergone three iterations.
The first generation of "inorganic solid-state electrochromic materials" are mostly used in the construction field, but their own toxicity is strong, weight, thickness, discoloration speed, etc. can not meet the volume requirements of mobile products such as mobile phones; the second generation of "liquid electrochromic materials" compared to the first generation of products color change speed is relatively faster, but there are still such problems as high power consumption, unlikable color, easy to leak liquid (there is also a certain degree of toxicity);
The third generation of "flexible electrochromic materials" basically solves the shortcomings of the first two generations of materials, and the overall is more thin and durable, and it is also the first choice for smart phones.
Below, let's briefly understand the mobile phones that have introduced electrochromic discoloration processes.
OnePlus Concept One
At the CES show in early 2020, OnePlus showcased a concept phone called OnePlus Concept One, which used the same leather + color-changing glass of the McLaren sports car on the back, completely hiding the rear camera. The wonderful thing is that when the user runs the camera APP or other applications that need to take pictures or scan, the color-changing glass can change from black to transparent in only 0.7 seconds, revealing the 3 cameras and flash modules inside, the speed is even faster than waking up the camera, and 1 hour only consumes the battery 2mAh ~ 3mAh, can be powered on for 1000 hours, and the cycle life can be close to 200,000 times.
OnePlus refers to onePlus Concept One's electrochromic glass as the "ECMF" scheme. In industrial design, colors, materials, and processes (Color, Material, Finishing) are often referred to as CMF, and the "E" in ECMF represents electronic.
Specifically, the electrochromic glass of onePlus Concept One uses a five-layer structure, the upper and lower layers are AR coated 0.15mm thick glass (GLASS); the middle two layers are transparent conductive films (ITOs), which contain transparent nanoscale lines to control the current and voltage of color change; and the central layer is only 0.05mm thick EC material responsible for color change.
The total thickness of the electrochromic glass is only 0.35mm, which has raised the transmittance to another height through a series of optical optimizations, and the unique ND filter function is also brought by controlling the color of the back cover glass, which can also shoot special effects such as silk flowing water even during the day.
Vivo intelligent color-changing glass technology
At the beginning of September 2020, Vivo officially announced its intelligent color-changing glass technology on Weibo, which was inspired by the portholes on the aircraft that can automatically change color, that is, the EC electrochromic process. The person in charge of vivo technology has revealed that the power consumption of vivo's intelligent color-changing glass technology is very small, and the body glass will consume power only when the mobile phone changes color, compared with the display power consumption of the AMOLED screen, its power consumption is basically negligible.
OnePlus 8T Concept
At the end of December 2020, OnePlus released another concept phone called the OnePlus 8T Concept, which uses a pattern similar to wave and flower pattern on the back cover, and adds a color-changing EC material containing metal oxides to its interior.
The phone uses electrochromic glass to expand a notification system - when a phone calls in, the back cover of the phone automatically changes color, presenting a display effect similar to a breathing lamp. At the same time, radar sensors are integrated into the bulge of the OnePlus 8T Concept's back camera to help the phone "sense, image, locate and track objects." For example, when you see the back of the phone changing color by sensing the user's breathing through radar; for example, when you see the back of the phone change color, you know that the call is coming, at this time you can use gestures to answer or hang up without touching the phone.
Nubia also showed a Red Devil mobile phone that introduced electrochromic discoloration technology in mid-December 2020, by tapping the side button of the fuselage, the black mobile phone back cover can become transparent to expose the chip inside, and the sense of technology is explosive.
OPPO Reno5 Pro+ Artist Limited Edition
Also released at the end of December 2020, OPPO Reno5 Pro+ Artist Limited Edition is the world's first mass production mobile phone equipped with electrochromic technology, which uses a gelatinous organic small molecule material as a flexible electrochromic diaphragm (0.15mm thick, 1.5g weight), semi-solid organic electrolyte material is safe and non-toxic, and has passed the SGS authoritative certification. OPPO also uses a packaging process close to the LCD, so that the flexible electrochromic diaphragm is isolated from water oxygen, which can achieve more than 30,000 cycle life, and can be used for more than 3 years under normal use.
Simply tap the back of the Reno5 Pro+ Artist Limited Edition body with your knuckles and the color of the back cover can change from gray to blue, providing a fantastic visual impact. In order to enhance the sense of ceremony, the product also prepared a "bang bang affection" function, after the two mobile phones complete the binding, double-click the back shell can be "flirting", so that the other party's mobile phone receives the heartwarming mobile phone body effects, you can also double-click the back shell to respond to each other, so that couples using OPPO Reno5 Pro+ artist custom version feel each other's heartbeat, truly "ECG induction".
OPPO Reno6 Pro+ Conan Limited Edition
In July 2021, OPPO released the Reno6 Pro + Conan Limited Edition to continue the electrochromic technology, and also for the first time mass-produced red electrochromic technology, which is more difficult than the previous generation. At the same time, this generation of electrochromic technology is more responsive. In the 25 ° normal temperature environment, the color change rate increased by about 20% year-on-year, and the color change performance in the low temperature environment was also better.
Huawei P50 Pro Ripple Cloud Wave Edition
Huawei's P50 Pro Ripple Cloud Wave Color Matching Edition phone released in July adopts a millisecond-level electro-dimming process, bringing a unique dynamic color change, and the body color and texture will produce sparkling visual effects when the call and alarm sound, completing the design concept proposed earlier on the OnePlus 8T Concept mobile phone.
Relame V25 Violet MSI Edition
True Self V25's unique "Purple Micro Star" color scheme strives to restore the changing stars at night in the Forbidden City, using a composite process to create a "starry sky texture design" - a double-grained double plating process that brings light into the center of the back cover and imprints the galaxy, which is very recognizable. Moreover, realme applies photochromic process for the first time in the price segment, delegating the process of high-end products, so that the true self V25 can achieve the dynamic effect of color change and circulation under different lights, forming a fantasy look of "holding the galaxy".
Lenovo Savior Y700 tablet
Lenovo Savior Y700 Gaming Tablet has a special version with inductive glass, and with the help of this unique material, the back of the tablet can show a solid color or honeycomb divergent design, making the whole product more technological and personalized.
brief summary
For a long time to come, off-screen cameras and electrochromic discoloration are the technical selling points for smartphones to achieve differentiation. With oppo and Huawei 'taking the lead', I believe that more high-end mobile phones will introduce this cool visual effects in the future. Due to the similar principle of electrochromic technology, mobile phone manufacturers are also directly purchasing mature solutions from suppliers such as Voger, Guangyi, Yapuxin, etc., so the main thing that can be competed between everyone is the style and color of the color change pattern, and the linkage of soft and hard combination with the system (such as telephone or WeChat notifications, etc.). As ordinary consumers, we just hope that the electrochromic process will be "married" to more mainstream priced mobile phones (such as the real V25).