Liquid crystal displays (LCD) are an indispensable part of modern TVs, smartphones and tablets.In LCD screens, light-emitting diodes (LEDs) produce white background light, which is then irradiated to the viewer through an ultra-thin liquid crystal layer.The crystal layer is divided into many segments (pixels), and their respective light transmittance can be adjusted by applying an electric field.In this way, each pixel emits light with its unique brightness (and the color presented through the color filter).
In flat-panel TVs equipped with traditional LEDs, the necessary backlight is produced by hundreds of LEDs; since a single LED requires a relatively large space, it is impossible to have more space.The disadvantage is obvious: it is impossible to achieve truly uniform LCD screen lighting with such a rough LED matrix.Therefore, when the first batch of screens adopting the new mini-LED technology came out in 2020, the industry aroused great enthusiasm.Since mini-LEDs are very small (0.05 to 0.2 mm) compared to traditional LEDs, it is now possible to generate backlights from tens of thousands of mini-LED light sources.Mini LEDs are bundled into so-called lighting areas, where each area is still much smaller than traditional LEDs.Through targeted control of each area, compared with traditional LEDs, the backlight intensity can be better spatially controlled.Therefore, TV viewers can expect significantly improved contrast and deeper blacks.In addition, mini-LED technology is good at producing extremely high dynamic range (HDR) and lower power consumption.
The manufacture of LEDs or mini-LEDs is far more complicated than the surface simplicity implied by the components—especially because some of the necessary manufacturing steps must be performed under vacuum conditions.In the first step, the MOCVD (Metal Organic Chemical Vapor Deposition) process is used to coat a metal organic layer on the wafer.In this process, the layered substance is attached to the existing crystal lattice in an atomically ordered manner: only a few atomic layers thick, which happens to adopt the crystal structure of the wafer.To ensure that the coating does not contain any impurities, this process step must be carried out under vacuum protection.This is where the value-added tax valve comes into play.The world’s largest manufacturer of MOCVD systems—with company headquarters in Germany, China, and the United States—relies on VAT vacuum valves.
In order to produce positive-negative conversion in the LED, an extra ultra-thin layer must be deposited and then etched away in the correct position.This delicate task is best accomplished through the interaction of two plasma-enhanced thin film processes: plasma-enhanced chemical vapor deposition (PECVD) for depositing layers, and plasma chemical dry etching for partial removal of them.Since these processes must also be carried out under vacuum conditions, the VAT vacuum valve also plays an important role here.
When a real breakthrough occurs in the future, VAT valves will definitely become one of them.After all, according to experts, mini-LEDs are just a stopover point to a smaller light source: micro-LEDs.Compared with mini-LEDs, these true miniature components are 50 to 100 times smaller.Surprised: The current smallest micro-LED has a side length of 3 microns, which is three thousandths of a millimeter!But it’s not just the size difference that makes micro LEDs so special.On the contrary, micro-LED technology represents a true paradigm shift.Compared with LCD screens, (mini) LEDs play a rather inconspicuous secondary role as a background light source. In micro LED screens, each pixel is self-luminous, dimmable and can be completely turned off.The additional backlight-and the associated technical uncertainty-is therefore no longer needed at all!
Although Micro-LED is small, the effect is huge.The transition from micro to micro LED technology has brought huge advantages.Some of them are visible, such as larger color spectrum, higher brightness, sharper contrast, and faster refresh rate.Others, such as lower power consumption and longer life, are intangible, but equally important.In this context, a new generation of LEDs is very likely to become a veritable game changer.
VAT Group AG published this content on December 14, 2021, and is solely responsible for the information contained in it.Distributed by the public at 06:57:28 on December 14, 2021, UTC time, unedited and unaltered.
Post time: Jan-05-2022
