New application of NCVM process: 5G communication

NCVM  Process Introduction

The NCVM ((Non-Conductive Vacuum Metallizing) ) process is applied to the plastic substrate to present a metallic texture and appearance. When communication products transmit or receive signals, because NCVM is an island-shaped discontinuous metal film, it can prevent the accumulation of electromagnetic fields from interfering with the RF or ESD (electrostatic discharge) performance of communication products. In the early days of development, the technology was applied to light, thin and short 3C products, such as mobile phones, PDAs, GPS satellite navigation, Bluetooth headsets, etc. Recently, due to the rapid development of 5G communications and the gradient color process of the back cover of mobile phones, this technology has generated more attention and gradually being adopted.

5G Communication Introduction

Today's wireless communication technologies use electromagnetic waves to transmit information. Electromagnetic waves have many wavelengths and frequency bands. At present, the most commonly used band of 4G LTE is 450 MHz~3800 MHz. This frequency band is relatively low frequency, and the low frequency characteristic is low power consumption. The penetration power is low but the diffraction ability is strong. As the demand for information transmission has grown over the years, 4G has gradually been unable to meet the demand. In recent years, countries have invested a lot of resources in the development and construction of 5G communications.

5G communication refers to the 5th Generation Mobile Networks, which mainly covers the two mainstream frequency bands sub 6GHz (below 6 GHz) and above 24GHz (mmWave). In terms of physical characteristics, the higher the frequency, the shorter the wavelength; the penetrating power is strong but the transmission distance is short, so 5G communication combines the existing 4G LTE with wide coverage and high-speed millimeter-wave broadband technology.

5G market applications

When high-bandwidth (eMBB) and low-latency (URLLC) domain characteristics are required, high-frequency millimeter-wave frequency bands are suitable for use in products such as: augmented reality (AR), telemedicine, self-driving, car networking... etc. When low power consumption, wide coverage, stable connection and other characteristics are required, it is suitable to use the sub 6GHz low frequency band for products such as: monitors, smart home appliances, smart factories, parking grids, Internet of Things... etc.

The application of 5G in self-driving cars includes real-time monitoring of the environment outside the car, signal transmission to the processor, and integrated computing on the cloud platform. Presently, many car manufacturers have installed on-board sensors behind the car logo. To operate and maintain the metal texture and appearance of the car logo, NCVM coatings are used on the logo parts and laser marking of the car factory logo.

Recently many 5G mobile phones have been gradually developed and put into the market. It is not difficult to find from these mobile phones that the back covers are made of plastic material and matched with NCVM process or even metal particle paint to enhance the metallic texture effect. Plastic material is used in place of metal because the multiple-input multiple-output (MIMO) technology adopted by 5G mobile phones requires the use of more antennas, and the size of the antenna required for millimeter-wave bandwidth is extremely susceptible to metal interference. Glass or ceramic can also be used in place of the metal, however glass and Ceramic back covers are not favored by manufacturers due to their bulky, heavy, and fragile characteristics.

NCVM process adjustment

NCVM is the first process developed by DAH YOUNG. The plating method adopts PVD evaporation. The indium tin alloy material is placed on the high melting point carrier in the two electrodes. The carrier is heated in a high vacuum environment and the indium tin alloy material is heated, then melted and evaporated to diffuse to the surface of the plastic substrate to form an island-shaped discontinuous metal film. During the coating process, special attention is paid to the thickness and uniformity of the coating to take into account the best gloss appearance and the maximum resistance of the film. The coating at different positions can also be finely controlled Thickness and other process methods to achieve dazzling color gradient effect.

Image Source: Huawei Mobile