ASUS ZenFone 6 flips not only the camera, but the entire world of mobile photography
While the competition obsesses over the number of lenses, ASUS ZenFone 6 focuses on its notchless all-screen display and Flip Camera, which maximize the quality of the front camera and herald a new era of photography. The key lies in the use of liquid metal, a precision stepper motor, and a whole raft of futuristic technologies. Behind Flip Camera are many amazing technical details made for power users a credit to the professional persistence of ASUS design team.
▲ Behind ASUS ZenFone 6’s all-screen design: not following trends, but following users' needs. (picture/ CCFun)
“According to our market research, a large proportion of ASUS smartphone users are power users.” says the
Smartphone Division director, Shawn Chang. Among those power users, there are two major groups: technology lovers and photo lovers. Right from the start, ASUS decided to make a phone to meet the needs of these target users, satisfying not only tech aficionados, but also delivering a high-quality photography experience for photo enthusiasts.
Finding the balance between screen, camera and battery
“The design process for ZenFone 6 started in September 2017. At that time, there were no notched displays on the market. The two main design cores were an all-screen display and long battery life. We believed that power users would be highly attracted to an all-screen design, and since they are heavily reliant on their phone, battery life would be another major consideration for them,” says ZenFone Design Center Director, Pete Lin.
▲ Pete Lin, ZenFone Design Center Director. (picture/ CCFun)
From establishing the core design to the completed design, hundreds of raw models were created. These included smaller notches, water-drop screens and many other ideas. In order achieve longer battery life, ASUS changed the traditional all-balanced design to one with a streamlined, 3D-curved back cover. For the best all-screen feel, ASUS choose a water-drop screen, which had not been seen on the market at the time. However, when ASUS realized the competitors would release the water-drop screen before them, they had to abandon this approach.
At that time, there was another ongoing design in the works. This was closer to a 'dream phone', and more like a concept phone. The design branches continued to be developed, including hole-punch, slider and semi-slider designs. ASUS almost adopted the semi-slider design in the first quarter of 2018. Pete Lin recalls, “The semi-slider could slide up and down, and it can put two lenses to capture more light, with two speakers in the bottom for multimedia functions.”
In the end, there was a big problem with the semi-slider design: the sliding components limited the space available for a large battery, so it failed to meet the original design criteria. So, this design was also abandoned once again.
▲ Water-drop and hole-punch displays were once considered for ZenFone 6. (picture/ CCFun)
The final design chosen was initially unpopular with the design team. Many designers thought the idea was too strange, how on earth could we make it work? But others believed that the concept had the potential to meet all the needs of our customers. The previous designs, apart from the all-screen display, did not offer any other substantial benefits. After discussions, we realized that this design is new to the market: an all-screen display, with the finest photographic quality and a camera that offers the same quality for front and rear use. So we decided to go down this route. “It's so bold, especially with such a distinctive design, that even the design team struggled to fully accept it in the beginning” says Pete Lin.
The beginning of the challenge
This decision now gave the design team a stage to play on. The first thing to solve was the problem of volume. Initially, they tried to consider many possible challenges for users, such as if the module pinches the hand, or keeps opening on the desk. So they added necessary sensors in the camera module, which made it hard to reduce the size of the module. Eventually, they choose the most streamlined shape of a cuboid so as to maximize the internal space.
▲ ZenFone 6's camera module adopts a cuboid shape, in order to contain all the parts and not to affect the internal body space. (picture／CCFun)
The minimalist design of ZenFone 6 uses an ultra-precise polishing technique, which makes the lines and the surfaces clearly visible, just like a Swiss watch, adding details and value to the camera module. “The details are actually very complex, which includes some extreme crafts like drawing, polishing, and sandblasting”, says Pete Lin. Take the space for the camera module for example: if you look carefully, you can see straight stripes (like a pinstripe suit!). And for two lenses show a concentric-circle reflection, and are both the same color and size. The whole camera module is coated in black.
▲ ZenFone 6 comes in Midnight Black or Twilight Silver: Midnight Black has a vibrant blue logo, and Twilight Silver comes with a futuristic gradient color. (picture／CCFun)
Another important component is the stepper motor. At first we wanted to use a manual or semi-automatic mechanism for flipping the camera module, but the team found that the user experience was not great, so they opted for a fully automatic flip mechanism. This was a difficult challenge for the team, and the end result is the custom precision stepper motor. This delivers ultra-precise electrical control of the module movements, including its swing amplitude and speed. Miniature stepper motors are tiny marvels: the size of the parts, the cover polishing and assembly process are comparable to the craft of watchmaking.
▲ The parts in ZenFone 6's camera module are precision crafted: some are smaller than those in a watch. (picture／CCFun)
ZenFone 6 is not only important for its appearance, but also for the user experience. When you turn on the Flip Camera, its speed is precisely controlled, so it doesn't pop out too quickly, and closes elegantly, like a door on a luxury car. This is controlled by the custom stepper motor, using electrical current to control the movement. However, the actual angles, speed and precision were not what the team had specified, so a gearbox was used to adjust the gear ratio to the most accurate angle. In order to fit the stepper motor into the phone, another gear set was added to change the position of the axis, cleverly achieving the triple goals of phone size, appearance and user experience.
The Savior: Liquid Metal
The most important material used in the Flip Camera is liquid metal (amorphous metal alloy). In order to minimize the size of the camera module, the design team was worried about the impact on durability. The thickness of many parts of the camera module is only 0.4 mm, which is about the thickness of five sheets of photocopy paper. At this thickness, whatever material is used — plastic, aluminum or stainless steel — it can be broken by the poke of a fingernail. The ASUS development team researched a solution, and the answer was liquid metal.
“Liquid metal is not actually liquid: everyone hears the words liquid metal and probably thinks of the Terminator, imaging it's like mercury”, says Pete Lin, “What is liquid metal? Its scientific name is amorphous metal alloy. It's a type of alloy that's solid at normal temperatures, but has the atomic structure of a liquid.”
The physical state is equivalent to glass, so another name for it is metallic glass. Its characteristics are strength and flexibility. It's four times tougher than stainless steel. When we found this material, we were like “Wow!” It seemed to the team that they now had a chance to create the device. But the downside is that it is very difficult to process, and needs to be as finely polished as a Swiss watch.
“Standard watches are made of 316 stainless steel, which is easy to polish and the related skills are mature. The 904 stainless steel of Rolex is the same. As for liquid metal, the surface is tougher than a Rolex: if it bump with Rolex, Rolex will be destroyed.” However, it’s difficult to polish the liquid metal, not to mention creating a brushed finish or edge chamfers. Even the supplier of the liquid metal had never done this before.
▲ ASUS ZenFone 6’s camera module is built like a premium Swiss watch. (picture/ CCFun)
The reason why liquid metal is rare is that unwanted holes are easily formed in it during the manufacturing process. If there are holes, this expensive material needs to be discarded, and there are very few willing suppliers, except for the interior parts of some premium products. ASUS broke through many technical limitations, and adapted an evacuated die-casting process, which totally eliminates the chance of holes. So the entire Flip Camera module, including the axes, can be made of liquid metal.
After the liquid metal is die-cast, it must be cut, but because it's very hard, the initial CNC milling tool and scissors are easily deformed and damaged. Instead we chose a water jet cutter, which is cheaper. However, the water jet cutter can't do very fine work. When cutting it, the corners and edges remain, and the back still has to be trimmed by CNC. The assembly of the upper and lower frame of the camera module requires high precision, so ASUS had to do a rare thing in the industry: engrave laser serial numbers inside the upper and lower parts of the module, for precise assembly. In this way, each part can only be matched with a part showing an identical serial number. When it's time to join and polish the parts, they will be perfectly matched. But the downside is that when one part is broken, a whole set of modules is trashed.
▲ ZenFone 6’s camera module is made of liquid metal, with water jet cutting. (picture/ CCFun)
Each side of the camera module is processed with a premium polishing process, including a brushed-metal finish, polishing and sandblasting. “Usually, sandblasting is used to cover up flaws, but our design is so detailed that sandblasting is part of the actual design. We polish the whole module to a glossy finish before sandblasting” explains Pete. “Blasting it directly would not be elegant enough, we deliberately want to show the sandblasting effect, so there are several polishing procedures to start with, and then it's sprayed to highlight the metallic effect. So we added several polishing processes, just to create a better sandblasted appearance.” “After that, it goes to laser engraving.”
“That’s like the design of a watch, which needs to look good at every angle. You don't necessarily see the back of a watch, but the craftsmanship is still there. This is the professional spirit that has always existed at ASUS.”
Upgrade the overall experience of shooting and video recording
Now let's take a look at the liquid metal: what are its advantages? “Let’s talk about the stepper motor first. We had to test it for up to 100,000 flips in order to pass our quality checks,” says Shawn Chang. “Secondly, it had to pass a 125cm drop test, and not only once, but nearly 100 times with the camera module opened. Thanks to the liquid metal, it passed all the drop tests in different usage scenarios.”
In reality, there will rarely be a situation where the phone is dropped with the camera module fully open. That’s because it has a preventative safety feature in the software. When the gravity sensor detects a change of speed and movement, it will retract the camera module instantly to a safe position.
It's not only the hardware, but the camera software is also designed to give practical benefits: Flip Camera gives the same quality whether it's taking landscapes, selfies, video calls, live streaming or group selfies. And the all-screen design doesn’t have any trade-offs for front camera quality, in fact it's even better. In Free Angle mode, the angle of Flip Camera module can be freely controlled, so you can easily control the camera angle. For example, when shooting low-angle shots, you no longer need to squat to get a perfect shot. And for taking panoramic photos, you don’t even have to move the phone: the Flip Camera module can rotate automatically, providing more stability and a better chance of a successful shot. For panoramic selfies, just put the phone down and the camera module can rotate up to 180°, so everyone fits in the shot. With the wide-angle lens, 180° rotation gives almost 360° coverage. There's also motion tracking, which automatically tracks the subject whether it's your children or your pets. In short, Flip Camera enhances the overall photographic and video experience.
The pride of the motherboard technology
ZenFone 6's second design objective is the battery life. Lin is almost driven to yelling, “The battery is probably one of the few parts with almost no breakthroughs!” The 5,000mAh battery is just so big, and our camera module is bigger than the competitors’, resulting in less space for the motherboard. The hardware engineering team can’t even find anywhere to put even the basic electronic components.
But as Lin points out, the engineers figured out a solution called Double Layer, which involves splitting the motherboard into two parts, and stacking the two parts to minimize the space used. Motherboards with circuits on both sides are quite normal, but the idea of stacking is rare. One board with two sides is fairly common, but it's rare to use three-dimensional space like this.
▲ ZenFone 6 introduces the Double Layer technology, which means splitting the motherboard into two parts and stacking them up together to minimize the space used. (picture/ CCFun)
However, this is still not enough. A motherboard consists of six to seven layers of circuits, and some functions require a connection between different layers, which necessitates drilling holes. But there's not enough space in ZenFone 6, so the engineers came up with a method called Anylayer. Normally, the drilling process doesn’t distinguish which layers are to be connected, they just drill the whole layers to save cost and time, but that sacrifices space.
ASUS instead decided to break up each of the six or seven layers, laser-drill the holes on each separate layer, then glue the layers together. “It’s time-consuming and expensive, and the yield is relatively low, which gives the developing team pain but it's great for the consumer, because it's real miniaturization, cramming the battery in the phone.” Lin says.
Shawn Chang added, among Android phones, ZenFone 6 is probably one that takes the most time and dedication to build. Even competitors’ flagship phones can’t make their motherboards this small. Motherboards are an area of technology where ASUS has always been outstanding. Heat dissipation is also solved at the same time: all these are all very complex technologies.
Back to basics
Last year, ASUS announced that its mobile phone business will shift its focus towards gaming and power users. ZenFone 6 is the first product designed for power users.
Chang said that the main design idea is to focus on the basic user experience and make the consumers feel the intimacy of our designs. “What we are talking about is very fundamental. What makes a good phone? Firstly, it's about the speed: fast and smooth. Secondly, the quality of the camera experience. Then the long-lasting power. So we kept asking ourselves, 'Do power users need a fancy product?' And the answer is 'No'. They only need a good phone.”
“We tried to incorporate these elements into ZenFone 6, so a lot of the design is not as showy as it could be. But there are a lot of intimate design details, while maintaining the delicate texture of a good phone. Take the camera module for example: it's polished like the cover of a Swiss watch, that’s the quality we’re taking about. It’s not something fancy, but it’s done in a down-to-earth manner.”
Chang mentioned that during our work on several generations of ZenFone, we have continued to learn and think. For ZenFone 6, the goal is customer satisfaction. Instead of fancy new features, we want to return to the true essentials. Even though the Flip Camera is truly innovative, it’s the result of focusing on the important basics.
▲ ZenFone 6’s all-screen display and Flip Camera are the result of returning to the essentials of customer satisfaction. (picture/ CCFun)
“We struggled internally for a long time. Should we say ZenFone 6 is a Flip Camera phone and make everyone impressed like “Wow!”? Or should the starting point be the all-screen display, long battery life and Flip Camera is just something that results from other factors which intended to solve the problem of poor-quality front cameras." Chang explains. "In fact, we never intended to make a Flip Camera phone. Instead, all we wanted to do was make a phone that tech lovers love, and at the same time deliver a great photography experience.”
In this competitive all-screen market, there are many innovative designs. The Flip Camera on ZenFone 6 is not only the solution to an all-screen display, but it also solves the problem of poor front-camera quality. It even exceeds our expectations, making the Flip Camera module a work of art — what it flips is not only the camera, but the entire photographic experience. As Pete Lin says “The beautiful appearance is subjective, but the details are objective.” We agree completely. In terms of returning to the basics, it remains to be seen if dual-camera systems can beat multiple-lens models. But what is certain is that ZenFone 6 is the winner in the front camera race.
Stuff says: Watch out people who wears Rolex!
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