Source: SuperNet.com
"Buzz buzz..." "Dong buzz..." "Da da da..."
They are all sounds made by mobile phone motors. As for why I wrote them with these familiar onomatopoeia, it is not to induce war, but to strengthen your perception. Today, let’s take a closer look at this inconspicuous gadget and talk about why this inconspicuous small component in a mobile phone can cause such a large-scale discussion.
The past and present life of mobile phone vibration motor
vibration motor, according to verified news first appeared on pagers, used to remind people of new news through vibration in some occasions where sound is inconvenient. According to the examination certificate, the first mobile phone equipped with a vibration motor in was the StarTAC produced by Moto in 1989. The emergence of mobile phone vibration function seems to be far earlier than we imagined. After
, with the continuous development of technology, various motors that we are familiar with have appeared one after another. Taking the iPhone we are most familiar with as an example, the first Z-axis linear motor of appeared on the CDMA version of iPhone 4.
Image source: iFixith
After the iPhone 55s returned to the columnar rotor motor again, it was the Taptic Engine we are all familiar with. Although it is not the first X-axis linear motor, since it is indeed a benchmark for public awareness, we will take it as the basis. As for the remaining flat rotor motors, I have not found the first model to use it yet, but I found a disassembly post from 2010. From this we can see that the technology of flat rotor motors has been quite old.
Classification and Principles of Mobile Phone Vibration Motors
Ahead we simply mentioned rotor motors and linear motors. Their full names are actually eccentric rotary mass transmissions (ERM) and linear resonant actuators (LRA). Classifying them in a simple way is the following table:
In the classification of LRA, the X-axis and Z-axis refer to the direction of motion of the counterweight blocks. We can briefly understand them through this simulated motion diagram.
Next, let’s talk about the principle part, which is also the reason why the two motors have huge differences in feel.
Eccentric rotating mass transmission (hereinafter referred to as the rotor motor) is driven by the motor, and the inertial force generated by the high-speed rotation of the eccentric block is obtained by the excitation force. is then passed to the entire phone through the middle frame of the phone to generate vibration. Why do I just say "rotor motor"? Because the principles of "ordinary rotor motor" and "flat rotor motor" that we can see are actually the same, it is just to remove the eccentric block, and then remove a set of coils on the rotor, or add a set of counterweight blocks, so that the rotor itself becomes an "eccentric block" and rotates and generates vibration.
coin-shaped rotor motor structure diagram: Precision Microdrives
The linear resonant actuator (hereinafter referred to as linear motor) generates a magnetic field by energizing the coil, driving the permanent magnet counterweight block in the center of the motor, and slides up and down or left and right in the track, thereby generating vibration. Of course, there is another type, which is a linear motor that is used on the iPhone 6s. The counterweight block moves on the center fixed axis. However, due to the wear of the axis after long-term use, the vibration sense is abnormal, and this design was later cancelled.
This direct sliding momentum will inevitably produce friction, so it can also be seen from the disassembly that black liquid will be injected into the tracks of the linear motor. According to what I have learned, that liquid is not a simple lubricant, but a liquid magnet, mainly for internal heat dissipation.
The principle of Z-axis linear motor is the same, except that the left and right movement of the counterweight block is changed to the upper and lower directions of the Z-axis direction, so the thickness of the motor is a major influencing factor on its vibration sense, and therefore the vibration of the Z-axis linear motor is inherently inferior to that of the X-axis linear motor.There are also Z-axis linear motors of various sizes on the market. Here we use Xiaomi 8 and Samsung S10 for comparison:
is Samsung S10 on the left and Xiaomi 8
on the right. Why can't the rotor motor achieve "dadada" like a linear motor? There is a preparation time for the start and stop of the rotor motor. The vibration frequency brought by the motor from stationary to lap speed is constantly increasing, and the vibration at a fixed frequency is maintained after reaching the maximum. Although this acceleration time is very short, it does exist.
Similarly, from the maximum speed to the power off and stop, the motor gradually decreases the speed until it stops, and the frequency gradually decreases. Therefore, there is a slight sense of drag. In addition to having a huge acceleration, linear motors can reduce acceleration time, and also have a limiting structure inside the motor to prevent "residual vibration".
Of course, in addition to this reason, since the "centrifugal force" generated by the rotor motor changes at all times, forces in different directions are generated. When the direction change speed reaches a certain size, it will be converted into "vibration". Just like the transition of vibration frequency, even if it is small, it can be perceived. The movement of linear motors on a single coordinate axis makes the perception clearer and more accurate.
How to choose a vibration motor for manufacturers
Price factors
In business, cost and profit are always the first consideration. Although both are vibration motors, the prices are very different. The most obvious comparison, taking the iPhone as an example, the total cost of the iPhone 7 electronic machinery given by some media is about US$16.7, and the Taptic Engine is predicted to account for US$7-10. Even if you search for the price of rotor motors used by Taptic Engine and iPhone 5s on Taobao, you will find that they are dozens of times different. Although the seller's selling price does not completely represent the cost of the material, it can be used as a differentiated reference.
Considering the motor itself, linear motors have more complex processes and higher parts accuracy requirements. At the same time, in order to achieve precise control of motor vibration, the linear motor needs additional planning of the drive circuit. Compared to the rotor motor using DC power, the simple and crude vibration that can be generated by electricity through the motherboard is undoubtedly a lot more expensive.
As the leader in mobile phone vibration motors, Taptic Engine is not surprisingly a leader in the vibrating motors. In addition to various chips on the line, a Hall sensor is also placed at the coil inside the motor, which can detect the strength of the magnetic field, so that its voltage can change with the intensity of the magnetic field, and achieve accurate control of the counterweight blocks, and finally feedback a clean and neat vibration sense. In order to achieve more stable vibration of such a large motor, Apple also made additional fixing brackets for the Taptic Engine and then used screws to fix them on the middle frame. Compared with the "double-sided adhesive process" of most models, these are real costs.
Structural considerations
Whether it is an X-axis linear motor or a Z-axis linear motor, it has a larger volume than a rotor motor. In this kind of inch of land inside the mobile phone, it can affect the whole body with one move. A larger motor means a smaller battery/smaller speaker/headphone jack cancellation (nothing is now anyway) than re-planning the layout for the sake of a single feeling of the user, which is better to give users more perception and configuration. Taking Redmi's K20 Pro as an example, a small columnar rotor motor was chosen to plug into a larger speaker.
It can also be seen from the disassembly of iPhones of all generations that in order to work hard on user experience configuration, such as adding larger speakers, larger camera modules, and larger Taptic Engine, Apple can only continuously strengthen integration and change the shape of the battery. And when all these optimizations and improvements cannot be achieved technically or costly, it is impossible to choose a better motor. For mobile phones, horizontal space is much more precious than vertical space, which is one of the important reasons why manufacturers choose Z-axis linear motors instead of X-axis linear motors.
function requirements
Still take the iPhone as an example. In order to achieve feedback with iOS special effects, such as the roller clicking feeling in the time setting, Apple used an X-axis linear motor.Starting from iPhone 7, in order to simulate the cancelled physical home button, Apple switched to a larger TapticEngine, and achieved the effect of fake and real through the technology mentioned above. Back to Android, Meizu, as a representative, realized the virtual game shoulder key that simulates physical keys through its mEngine at the Flyme press conference in January last year.
How do we choose a vibration motor
Since mobile phone manufacturers are becoming more and more "innocent", and with the price war between manufacturers, products will inevitably "shrink", and parts like motors that have "not strong perception" are also considered a severely affected area. As consumers, how do we choose a good vibration motor?
First of all, it can be clarified that due to the characteristics brought by the operating principle of the motor itself, any linear motor on the market currently belongs to the rotor motor. Without the exact source of the product, it is usually very intuitive to judge by the sound. The dragging feeling of the rotor motor is very obvious, that is, the "buzzing" sound is generated by . When the motor body can be observed, although both the flat rotor motor and the Z-axis linear motor are circular, the flat rotor motor does not require a longitudinal moving space, so it is much thinner in terms of thickness.
is also linear motor, how should we distinguish it?
naturally contacts a corner of the phone with a hard desktop and turns on the vibration. Since the movement of the X-axis linear motor is reflected in left and right vibration on the phone, it will produce a very obvious sensation of knocking, while the Z-axis will not have a strong feeling of . Similarly, it is easy to judge the position of the motor in the fuselage by touching the desktop with four corners, so there will be no "accident" in which many digital bloggers mistakenly judged the Z-axis linear motor of the Samsung Note 10 as an X-axis linear motor.
. In the case of both Z-axis linear motors, the thickness of the motor body further determines its vibration sense. So if your favorite model is not equipped with an X-axis linear motor, choosing a thicker Z-axis linear motor can also bring a good experience.
Of course, Taptic Engine is still Dugu Qiubai.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-