Understanding Automotive Optical Bonding in One Article

Automotive Display Optical Bonding (ADO) is a state-of-the-art technology that aims to enhance the visual experience within vehicle interiors. By utilizing optical bonding techniques, the display panel is seamlessly fused with the cover glass, resulting in a fully bonded structure that eliminates air gaps and reduces glare. This process, known as full lamination, vastly improves sunlight readability and touch sensitivity, providing drivers and passengers with an immersive and intuitive display interaction.

ADO technology offers several key benefits. Firstly, it significantly reduces the reflection of ambient light, resulting in improved visibility and reduced eye strain. This becomes particularly crucial when driving under bright sunlight or in challenging lighting conditions. Secondly, the absence of air gaps and increased touch sensitivity ensure a seamless touch experience, enabling precise and responsive interactions with the display. Lastly, the elimination of air gaps improves the overall durability and reliability of the display, making it more resistant to vibrations and impacts, and extending its lifespan.

With automotive display optical bonding, drivers and passengers can enjoy a more immersive and visually appealing experience while navigating through various infotainment systems, GPS navigation, driver assistance features, and other vehicle control functions. This advanced technology not only enhances safety and convenience but also adds a touch of sophistication to modern vehicle interiors.

As the development of automotive connectivity accelerates, it is driving the rapid iteration and upgrade of in-car display screens and entertainment systems. In the current stage of intelligent cabins, the trends of large-screen interaction and multi-screen integration have taken shape.

To meet the increasing demands of consumers for display screen quality, the related manufacturing processes for display screens are also rapidly advancing. One of the core processes in display screen production is optical bonding. Currently, major bonding factories are moving away from the previous frame bonding process and transitioning towards optical full bonding technology.

What is Optical Full Bonding?

Looking at the structure of the entire screen from top to bottom, it consists of cover glass, touch panel module (TP), and liquid crystal display (LCD)/organic light-emitting diode (OLED). These three components are bonded together to form the commonly known touch display module.

Currently, there are two types of bonding methods:

1. Frame bonding, also known as adhesive bonding, simply fixes the touch panel and display screen with double-sided adhesive. There is an air layer between the display screen and the touch panel.

2. Full bonding technology, also known as full lamination or non-air-gap technology, completely bonds the display screen and touch panel seamlessly together using adhesive.

Advantages of Optical Full Bonding:

- Compared to frame bonding, full bonding can reduce power consumption, improve image quality, and enhance product impact resistance.

- In frame bonding, the difference in refractive index between air and cover glass can cause light to reflect at the interface, affecting the clarity of the image. In full bonding, the refractive index of the optical adhesive is similar to that of glass, effectively reducing this adverse phenomenon.

- Optical full bonding can effectively prevent condensation and improve product reliability.

- Since there is no gap between the LCD and TP module, it can enhance product impact resistance.

Classification of Optical Full Bonding:

Currently, automotive full bonding is classified based on the process into 1st LAM (touch panel bonding) and 2nd LAM (LCD bonding).

Based on the different bonding materials, it can also be divided into OCA (Optically Clear Adhesive) and OCR.

- OCA (Optically Clear Adhesive): Solid-state adhesive. Its advantages include high production efficiency, uniform thickness, no overflow glue issues, and controllable bonding area. The current technological focus is on curved bonding and colored OCA that helps achieve the all-black integrated look.

- OCA optical transparent adhesive tape from TESA, the next generation adhesive suitable for flexible and foldable screens.

- OCR (Optical Clear Resin): Also known as LOCA (Liquid Optical Clear Adhesive). Liquid adhesive, also known as liquid glue. Liquid glue has good filling properties and advantages in curved bonding.

- Low viscosity liquid adhesive from Wacker, ideal for injection molding process and curved screen bonding.