Application of Neodymium Magnets in 3C Consumer Electronics

There are three main modules in consumer electronics that use magnets, namely the acoustic module, the motor module, and the magnetic attraction module.

1. Acoustic module

As the name suggests, the acoustic module is a sounding unit, commonly known as a loudspeaker. The performance of the speaker has a great influence on the sound quality.

A magnetic field will be generated in the energized wire. When the AC audio current passes through the coil of the speaker (that is, the voice coil), a corresponding magnetic field will be generated in the voice coil. This magnetic field interacts with the magnetic field generated by the magnet on the speaker. This effect The force makes the voice coil vibrate with the audio current in the magnetic field of the permanent magnet that comes with the speaker. The diaphragm and the voice coil of the speaker are connected together. When the voice coil and the diaphragm of the speaker vibrate together, the surrounding air is pushed to vibrate, and the speaker produces sound. As shown in the figure below, this is the principle of the horn.

The requirements for NdFeB magnets in the acoustic modules of different 3C products are also different

Mobile phone products such as the iPhone are used frequently and have certain requirements for the weight of the mobile phone, so high-performance (54SH) magnetic steel with small size is required to achieve the purpose of light weight
On a computer such as a Mac or iPad, on the one hand, sound quality needs to be considered, and on the other hand, its volume is larger than that of a mobile phone, and more space can be used, so it will use a slightly lower performance (52SH) with a larger volume and more shapes. Diversified magnetic steel
Watch products such as Watch are small in size and the user’s demand for them is generally that they can produce sound and do not have high requirements for sound quality. Therefore, magnets with low performance (50H) and small size are used.

2. Motor module: VCM voice coil motor and linear vibration motor

The VCM voice coil motor is an important part of the AF (Auto Focus) camera module. It can move the lens up and down to switch between near focus and far focus, making pictures clearer. Similar to the principle of the speaker, the magnetic steel provides a permanent magnetic field in the camera module, and the energized coil will be subjected to force in the magnetic field, thereby dragging the lens to move back and forth. Different lenses have different functions, and the shape and performance of the magnetic steel inside are quite different.

The linear vibration motor is the main device for mobile phone products to realize the vibration function. The energized coil is subjected to an ampere force in a magnetic field (provided by a neodymium-iron-boron magnet), which drives the motor to vibrate. Among them, LRA (Linear Resonance Actuator, Linear Resonance Actuator) is a motor motor widely used in smartphones, which provides tactile feedback through tactile effects. The quality of LRA performance directly affects the user’s tactile experience. The LRA is driven by alternating current. The alternating current can generate instantaneous high voltage, which makes the motor start and stop very fast, and the vibration feels just like your hand. Changing the frequency of alternating current can achieve different vibrations, matching various mobile phone usage scenarios. Depending on the type of motor, the shape and performance of the magnet are completely different.

3. Magnetic module

Magnetic attraction is the easiest to understand. It is to use the property that magnets are attractive to ferromagnetic substances. It is mainly used in various types of adsorption parts, such as various types of wireless charging adsorption parts, mobile phone watches, etc., and for example, the closure of computer screens, tablet All supports have magnets to play a role in adsorption. These adsorbents have different shapes and performances for different end products, and can be customized according to actual needs.

Other Applications of Magnets

A magnet, commonly known as a magnet, is composed of atoms such as iron, cobalt, and nickel, and is a substance that can generate a magnetic field. According to its shape, it can be divided into square magnets, cylindrical magnets, disc magnets, ring magnets, tile magnets, etc.; according to its properties, it can be divided into neodymium iron boron magnets, samarium cobalt magnets, ferrite magnets, etc. ;According to their magnetic persistence, they can be divided into permanent magnets and non-permanent magnets. Among them, permanent magnets can also be called natural magnets, which have permanent magnetism, while non-permanent magnets only appear magnetic under certain conditions. At present, magnets are widely used in industry, military, medicine, astronomy and other fields, and we will introduce them in detail below.

1. the application of magnets – – industry
In the traditional industrial field, since generators are used for power generation, transformers are used for power transmission, speakers are used for TV sets, motors, telephones, and radios are used for electric machinery, too many instruments and meters use magnetic steel. Coil structures, so it can be said that electrification would not be possible without magnetic materials.

2. Application of magnets – military
Ordinary sea mines or mines can only explode when they touch the target, but once a magnetic sensor is added to it, it can detect changes in the magnetic field when it is close to but not in contact with the target (suitable for steel objects such as tanks or warships) and trigger Mine or mine explosion, greatly improving the lethality.

The aircraft is easily detected by the enemy’s radar during flight. In order to avoid the monitoring of the enemy’s radar, a special layer of magnetic material (absorbing material) can be coated on the surface of the aircraft to absorb the electromagnetic waves emitted by the radar, so that only a small amount of Electromagnetic waves are reflected on the surface of the aircraft, and enemy radars cannot detect the radar echoes and cannot detect the aircraft, thus making the aircraft invisible.

3. the application of magnets – – medicine
The most important application of magnets in the medical field is nuclear magnetic resonance. Using this nuclear magnetic resonance imaging technology can diagnose abnormal human tissues and diagnose diseases. In addition, the interaction between the magnetic field and the meridians of the human body can also achieve magnetic therapy. At present, there are magnetic therapy pillows, magnetic therapy belts and other products.

4. Application of Magnets – Astronomy
The Northern Lights in astronomy are actually the result of the interaction between particles in the solar wind and the Earth’s magnetic field. The solar wind refers to the flow of high-energy charged particles emitted by the sun. When they reach the earth, they interact with the geomagnetic field, just as a wire with current is forced in the magnetic field, making these particles move and gather toward the north and south poles, and It collides with the thin gas at the high altitude of the earth, and as a result, the gas molecules are excited to emit light.