Apple’s latest smartphones come with a pressure-sensitive display that literally takes touchscreen interaction into another dimension. In addition to touch, swipe or gestures, in which 2 or more fingers are involved (the so-called multi-touch), iPhone 6s is also able to respond to the force of pressing. Thus, along with the detection of finger movement in two dimensions (along the X and Y axes), the device can register a screen shift along the Z axis. The technology is called the new generation of multi-touch. So what is 3D Touch? How it works? Why is it so important? And is there a 3D Touch in the iPhone SE?
Why is this needed?
3D Touch provides additional input control capabilities. This is similar to having a 2-button mouse: a light click on the screen is equivalent to a left click, and pressure is similar to a right click.
Keep in mind that the iPhone’s 3D Touch is not Force Touch technology used on the Apple Watch and MacBook trackpads. The latter only detects the touch, and the first detects 2 pressure levels: soft and hard. On the phone’s home screen, a simple click on the application icon launches the “Quick Actions” context menu - shortcuts for frequently used functions, such as taking a selfie or writing a text message. Stronger pressure on one of the options performs this action.
A soft press also allows you to view the contents of an email or website, while a harder press will open the selected message or page. So far, only a few applications support this technology, but, as in the case of multi-touch, it is likely that it will find more application in games.
3D Touch on iPhone: what is it and how does it work?
The smartphone feels the force of pressing, using microscopic sensors built into several layers of the screen. Apple itself says about 3D Touch that it is such a “technology that starts with a display that recognizes the applied pressure." More precisely, pressure creates forces that are detected by sensors called strain gauges.
As sensors, materials are used that, when bent, change the electrical signal. And deformation is caused by clicking on the screen. Even ordinary glass bends, but the iPhone 6s uses a more flexible, specially manufactured by the manufacturer Corning glass.
Most touch devices detect finger contact with the display using “capacitance”: electrical signals passing through the circuit change when they come into contact with a capacitor, that is, an object that carries an electric charge, such as the human body. When the finger touches a conductive surface such as glass, it closes the circuit with capacitive sensors below the surface of the panel, which leads to a detectable change in the electrical signal.
Capacitive sensors
Touch sensors are often made from indium tin oxide (ITO), an optically transparent material that conducts electricity. They can be considered as wires in a circuit, because that's how they behave, although the sensors themselves are actually a grid of dots on the screen.
Capacitive sensors are integrated into the backlight of the iPhone display, and each time they are pressed, they measure microscopic changes in the distance between the coating glass and the 8 x 12 pressure sensor matrix. The technology may seem simple enough, but it is not: there is no tiny ruler to measure the distance between two two-dimensional surfaces . Determining how much the glass is curved requires complex algorithms.
Apple Solution
Patents partially reveal what 3D Touch is. These are capacitive sensors made in the form of one of several serpentine circuits that correspond to the orientation of the forces detected by the main load cells. According to another patent, the technology includes 2 layers of sensors. The first serves to determine the strength, and the second to compensate for the temperature, since heat can lead to the expansion of materials and the potential for false signals. At the corners of the grid, the sensors are rotated 45 ° to detect deformation along the corner, and the internal sensors are oriented parallel to the edges of the display.
Changes in the electrical signal caused by physical forces at each load cell determine the so-called. center of force, and then compare the values with the readings of neighboring sensors, thereby establishing the position and pressure level. As stated in the patents, the screen "connects the measured difference with the electronic device." For example, if the iPhone receives more information on the left than on the right, then obviously one side of the display is pressed. When you touch the center of the screen, the signals will be symmetrical. This way you can get a fairly accurate picture of where and how much power is applied.
The technology has been used in Apple smartphone models starting from 6s, so for those who are interested in whether there is 3D Touch on the iPhone SE, the answer will be negative. Not the least role in this was also played by the price of the device, its small size and the complexity of mass production.
How to enable 3D Touch in iPhone 6? By default, this feature is already activated. But it can be turned off and on again at the request of the user. To do this, in the general settings, select the "Accessibility", then - 3D Touch - and switch the state to the desired.
Why is it important?
Many are still confused about what it is - 3D Touch, confusing it with a long press - a gesture that already exists on most touch devices. For example, touch and hold are used to select text or move / delete applications from the main screen. In principle, weak and strong pressing can be simulated using the long-term hold method, but it will not be so effective.
Why is 3D Touch more than just a trick?
By nature, prolonged retention takes some time. It takes about 0.5 seconds for it to work, while pressing provides an instant response to user actions. This is the biggest advantage of the iPhone 3D Touch, that this technology saves time and improves smartphone performance.
To create a touch feeling, vibration is applied. Apple has already used the haptics on the MacBook trackpad, which doesn’t actually slide down, but instead vibrates, simulating a button press. This is accomplished with a tiny motorized drive called the Taptic Engine.
Feedback
The Taptic Engine on the iPhone 6s provides tactile feedback in near real time. Apple claims that the vibrating system of a typical phone requires at least 10 vibrations to reach full power, but it only takes 1 cycle to start and stop the Taptic Engine, which lasts 10 or 15 ms for mini or full feedback. This provides a clear tactile sensation for soft and hard pressing.
Experts are impressed by the feedback from the iPhone. Sensors detect force and then the Taptic Engine provides the right response. This combination creates a very convincing click without moving parts.
Complex and costly solution
Apple was not the first company to create a pressure-sensitive phone, but it made significant investments in this technology. From a technical point of view, the hardware for creating a display that is capable of this is incredibly complex. It takes time, huge costs and investment in production. Since the 3D Touch idea is not innovative, the success of the iPhone 6s depended on how well its pressure sensitivity is implemented. And Apple did it.