Prospects for glass light guide plate in LCDs

Nov 25, 2022

There has been a recent resurgence of interest in glass light guides for use in LCDs. This is due to the increasing demand for more extensive and higher-resolution displays, as well as the need for greater power efficiency. In this article, we will explore some of the prospects for glass light guides in LCDs and discuss some of the challenges that need to be overcome in order to make them a reality.


As early as 1888, Austrian chemist Friedrich Reinitzig discovered liquid crystals and their special physical properties. Still, it was only in 1973 that this substance was first used to make digital displays for electronic calculators. And by the 2010s, engineers favored LCDs due to their low power consumption, and are now the main display device for computers and televisions.


The main principle of liquid crystal display is to stimulate the liquid crystal molecules with electric current to produce dots, lines, and surfaces with the back lamp to form the picture. In the LCD panel, the backlight module is the key component of the LCD, and its function is to provide a light source with uniform distribution and sufficient brightness. In the backlight module, the light guide plate (LGP), as the most important component, assumes the function of guiding light, and its design and manufacture are the key technology of the backlight module.


At present, the LCD backlight module to side light type, the light guide material is divided into organic transparent material and inorganic transparent material, the specific comparison of the two can be seen below.

Organic transparent material

Traditional LCD guide plate substrate commonly used PMMA, PC, MS, and ZEONOR. which, PMMA is a highly transparent amorphous plastic polymer, with a light transmission of 90% ~ 92%, and can transmit ultraviolet light up to 73.5%, a refractive index of 1.49, high mechanical strength, good toughness, a tensile strength of 60 ~ 75MPa, impact strength 12 ~ 13kJ/m2, stretchable orientation It is the most common material at present because of its UV resistance and anti-atmospheric aging performance and low cost.

Inorganic transparent material

The inorganic transparent material is mainly glass material, which is the new light guide material that emerged with the large size of LCD TV and displays high quality. As an emerging product, the main chemical composition of glass light guide is SiO2, with auxiliary components such as Al2O3, B2O3, Fe2O3, alkali metal oxides, alkaline earth metal oxides, etc., which can change the physical and chemical process performance of glass. According to the existing published patents and literature, the main research and development direction of glass light guide plates for glass auxiliary components to regulate the performance of glass light guide plate, such as mechanical properties, chemical stability, light guide quality, etc.

Advantages of Glass Light Guide Plate

Although organic transparent materials have excellent optical properties and low-cost price advantages, they are in very large size, ultra-thin LCD TV applications, their poor system strength, and thermal deformation is the biggest deficiency, while the coefficient of thermal expansion of plastic, size by the ambient temperature changes, requiring the structure to set aside a large safety gap, is not conducive to narrow bezel design.


And in the display industry, the development of thin has become an inevitable trend. For the current two mainstream displays OLED and LCD, as the latter requires backlighting so the display thickness of the duel has been at a disadvantage. In order to solve the problem of LCD display thickness as much as possible, the thinness of the light guide plate is the key. Therefore, glass substrate manufacturers Corning, and Asahi Glass, respectively, launched a glass light guide plate, so that LCD displays become thin, with light guide thickness down to about 1 ~ 2mm. And with the glass substrate production process technology being increasingly fine, the thinnest glass substrate can reach 0.1mm while having better mechanical properties, and excellent dimensional stability. It can be said that the application of glass light guide plates to LCD displays has brought great vitality.

Conclusion

Compared with traditional light guide panels, glass light guide panels have excellent mechanical properties and are the best alternative to traditional PMMA light guide panels, allowing for novel and stylish designs that are ultra-thin, lightweight, and large in size. Moreover, due to the high environmental resistance of the glass light guide plate and its small deformation during use, it is possible to achieve "zero bezel" through a narrow bezel design. However, there are still many urgent improvements to the glass guide plate, such as the optical properties of the glass, and production and processing problems, which need time to solve, in time, I believe the advantages of the glass guide plate can continue to expand.







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