This article is from the public account PingWest Pinwan (ID: wepingwest), author Jianguo, Ai Faner released with permission.

The border is still the back cover, or it is multi-dimensional interaction.

If counting from 1973, mobile phones have been with humans for decades, maybe older than you and me.

The main interface for humans to control mobile phones has changed from physical buttons to screens in these decades. But have you ever thought about leaving the screen and interacting with your phone in other ways?

Whether you think about it or not, anyway, mobile phone manufacturers are already trying it out.

For example, vivo NEX 3, Xiaomi MIX Alpha, etc., the first echelon brand of domestic mobile phones has either produced a production machine or exhibited an engineering machine or a concept machine. They have extended the screen display area to the side without exception. At the same time, the control dimension of the finger is increased.

People gave it a nice name-“Waterfall Display”, which is actually an advanced version of curved screen. Taking Huawei Mate30 Pro as an example, the side curvature of the screen has reached 88 °, and the border is almost invisible in the front viewing angle. At the same time, Huawei canceled the physical volume key and switched the volume by tapping the side screen and calling out the volume bar.

▲ HUAWEI Mate30 Pro

Although this change requires users to adapt, they all reveal a message: everyone is not satisfied that the interaction interface with mobile phones has only a front screen, and is trying to extend to the border (screen). In order to expand the user interface with mobile phones, the industry has actually worked hard for a long time.

Touchpad on the back of the phone

The early era of smart phones was full of flowers, with a variety of bright designs, and it was highly recognizable. It is not as homogeneous as the current mobile phone products.

For example, flip phone and slider phone, it was a functional embodiment at the time, and it also had mechanical beauty. But limited by technical bottlenecks, some weird ideas are mostly tried on the back of the phone.

Motorola ME600 is such a classic clamshell product that has no ancients and no comers. Due to the unique backward clamshell shape, it is called “backflip”. In the folded state, the front of the ME600 is the screen, and the back is the full keyboard-a camera and a flash. When the phone is extended 180 °, the screen and keyboard are on the same plane.

 Does the mobile interface have to be a front screen?

At this time, the back of the screen has also become the interface for human-computer interaction. Motorola placed a touchpad on this empty plane. You can browse the front screen casually while quietly sliding the touchpad with your finger holding the phone, double-clicking and selecting.

 Mobile interactive interface, must it be a front screen?

It seemed like a cool design at the time, but it wasn’t very convenient. Motorola only used this design in the next few phones, and abandoned it by the Razr XT910.

Coincidentally, OPPO, which has shown innovation in the past two years, also adopted a similar back touchpad solution at first, which seems to pay tribute to the ME600. In September 2013, OPPO launched the rotating lens mobile phone OPPO N1. In addition to the camera that can be rotated at the top, OPPO N1 has a built-in touchpad on the back.

The size of the touchpad is 3cm * 4cm, which integrates with the back cover in appearance. At that time, it was interpreted as “solving the problem of users using a large-screen mobile phone with one hand”, and users could perform operations such as swiping and clicking on the rear touchpad to support custom daily call functions.

 Does the mobile interface have to be a front screen?

▲ Image from androidauthority

Unfortunately, the actual use frequency of the touchpad is not high, and the user experience is not good. With the OPPO N1 mini, the rear touchpad design was cancelled, which is also one of the few short-lived features of OPPO’s innovative technology.

Although these attempts have failed, it is a good thing for the development of mobile phones.

Put the fingerprint module on the back

Looking now, the rear fingerprint recognition module is probably the most successful attempt to use the back of the phone.

The rear fingerprint mobile phone in the era of smart phones still comes from Motorola—MOTO MB860 released in 2011, which I was very much looking forward to. To be precise, its fingerprint module is located on the bezel on the top and back of the phone, and integrates the power button. This was a very advanced move at the time.

But because of the sliding fingerprint unlocking technology, the user experience is not satisfactory, so it has not yet become popular.

Until later, the fingerprint technology gradually matured, while the front screen became larger and larger. Volkswagen’s pursuit of a higher screen ratio has driven the fingerprint module that was originally on the front to the back of the phone.

Does the mobile interface have to be a front screen?

▲ OnePlus 6

In the period when screen fingerprints were not yet mature, a large part of Android smartphones used rear fingerprint solutions. It is placed above the back of the phone, to a certain extent, in line with the attitude of the user’s handshake, and can be touched blindly.

In order to highlight the differences, some mobile phones also support interactive actions such as swipe, long press, etc. on this fingerprint module to call out commonly used functions.

But in terms of appearance, the most inconsistent rear fingerprint module is still Nut Pro2. It combines the fingerprint and hammer’s logo into one, which is very comfortable on the look and feel.

 Does the mobile interface have to be a front screen?

▲ Nut Pro 2 and Nut Pro

Future possibilities

A waterfall screen ’s exploration of interaction emerged this year, which originally dates back to the Samsung Galaxy Note Edge in 2014. At that time, Samsung introduced this mobile phone with a straight screen and a curved surface, subverting the form of all smart phones. Samsung hopes that users can use this curved screen to perform quick switch operations, view SMS notifications, and so on.

Later things prove that a little curved screen area is not enough to make it stand alone as an operating space. But this does not prevent Samsung from pioneering curved screen phones. In the following years, Samsung insisted on launching mobile phones with curved surfaces on both sides, which eventually led the trend.

 Does the mobile interface have to be a front screen?

▲ Samsung’s patent for curved screen operation

The biggest problem with curved screens is that they are accidentally touched. This year’s curved screens are more curved, and the chance of accidental touches will be higher.

Because the curvature of the waterfall screen of vivo NEX 3 is close to 90 °, the frame of the hand will directly touch the screen. vivo canceled the physical buttons on the side of the fuselage, leaving only the physical switch button on the top for backup. At the same time, a pressure sensor from NDT is used. Users can adjust the volume by pressing the pressure-sensitive buttons embedded in the outer ring.

This is a technology that we can already experience, but there are still some technologies that have not been fully developed yet to be seen.

For example, ultrasound technology, the industry ’s research on ultrasound technology has not stopped for the past 5 years.

In 2016, Kang Shin, a professor in the Department of Electrical Engineering and Computational Science at the University of Michigan, was inspired by “Batman: The Dark Knight” and developed a software called “ForcePhone”. The sound that is close to the ultrasonic wave will change the “sound” when the user touches the screen or holds the body tightly. The microphone senses and then converts the signal into instructions through software, which then enables the mobile phone to complete the corresponding task. For example, you can call SOS by pinching your phone. But it failed to land.

 Does the mobile interface have to be a front screen?

In the last two years, some people have successfully applied it to mobile phones. For example, the fingerprints under the ultrasonic screen of Samsung S10 series phones, and the AirTriggers function implemented by ASUS ROG gaming phone 2 using ultrasonic technology.

AirTriggers is actually an ultrasonic module placed on both sides of the frame. Users can press the frame to implement operations such as movement and attack in the game, similar to the real operation of a gamepad. Despite ROG Gaming Phone 2 is a niche game, but its ultrasonic technology may be a breakthrough point for human-computer interaction.

 Does the mobile interface have to be a front screen?

▲ Photo from gsmarena

Xiantong Technology, which provides this technology, said that this ultrasonic module technology will not be limited to materials, whether it is glass, metal or ceramic body, it can adapt, which means that theoretically, in addition to the frame, mobile phones It can break through the screen and allow other parts to become interactive areas under the blessing of ultrasonic technology.

From a technical point of view, the industry currently requires more and more screens and more integrated body, but the space inside the mobile phone is gradually occupied by more and more parts, and the physical keys are cancelled. It has become a trend to make way for other parts. If you want to add an ultrasonic sensor module, its volume must be small enough.

Can we manipulate the phone naturally? Does such interaction have learning costs? Is there any other way to interact besides the border and back? These are the problems facing the industry, and we need to give them time to explore the road first.

The good news is that after years of development, the ultrasonic technology that is now commercially available on mobile phones allows us to see a bit of hope, at least to meet daily use, compared to the ultrasonic fingerprint technology that was more mature three years ago.

Apple canceled 3D Touch closed the screen multi-dimensional interaction window. Will ultrasound open the door to the next multi-dimensional interaction?