Shaped Screen Processing: New Demand Gives Rise To New Technology

Apple is the leader of the cell phone industry, leading one round of design trend after another. From the full-screen design to the shaped screen, its design concept has been widely emulated over the years.
The design revolution of the screen has also led to technological innovation in laser processing. Some years ago, the "Liuhai screen" "water drop screen" as a representative of the shaped screen, the production process put forward further requirements. Some flexible screen also need to reserve the camera or sensor position, the conventional processing means is more than enough to deal with.
In addition, there are other difficulties in screen processing. Traditional cell phone screen is 16:9 rectangular, four corners are right angles, in order to reserve the placement of the front camera, distance sensor, receiver, etc., the screen and the upper and lower body edges are a certain distance, the processing process is relatively simple. The aspect ratio of 18:9 full-screen cell phone, first of all, the screen ratio is generally greater than 80%, the screen edge is closer to the edge of the body, which leads to the screen may be more impact in the fall, resulting in a broken screen, in order to avoid this risk, reserved components and wiring space, the screen corners of the cut also need to use the shape of the non-right angle.
In a nutshell, the chamfer used in common OLED / LCD shaped screen can be divided into R corner cutting, U-shaped slot cutting, C corner cutting. For full-screen, the corners of the screen usually need to use the R corner cut, and at the same time through the addition of cushioning material to strengthen the edges, in order to prevent the screen from shattering, U-shaped slot cutting is mainly used in the top position of the screen, to reserve space for other components at the same time, to achieve a better visual effect and highlight its design features. At the same time, U-shaped slotting is the most difficult step in the entire cutting process, and it is also the main reason for the decline in screen yield.
In order to realize the processing of shaped screens, the commonly used processing methods include knife wheel machining, CNC grinding and laser processing. Traditionally, each of these processing methods has its own advantages, and each has some shortcomings.
Knife and wheel machining is the process of mechanically processing the screen to give it the desired shape. The advantage of this process does not belong to the thermal processing, to avoid high temperature screen yellowing or hot spot gap and other issues, while the processing equipment to choose a variety of relatively low cost. However, the defect is that the process requires precise control of the milling cutter pressure, speed, feed angle, knife design and grinding path, once the problem is very easy to change the stress characteristics of the glass itself, resulting in screen chipping scrap, the yield rate is not high enough. At the same time, the finished product is rough and not suitable for processing fine glass, sapphire and other materials. In addition, the splashed glass fragments need to be cleaned up, there is a certain risk of contamination, and long-term use will also cause wear and tear on the processing equipment.
CNC grinding processing, is formed by slowly rubbing the abrasive rod to form the shape that meets the requirements. Because of its abrasive number can be adjusted, chipping amount control is more stable, due to the LCD screen is a double-layer structure, control chipping is particularly important. However, CNC grinding processing speed is the slowest, processing efficiency is not satisfactory.
Laser processing, through the laser design graphics to realize the screen shaped processing. The advantage of this approach is that the process is simple, process generalization, the effect is stable, and can show stable and reliable processing results. The disadvantage is that the conventional CO2 laser cutting under the thermal effect can not be ignored, easy to form yellow edges affect the quality of the finished product.
In order to solve the adverse effects of thermal effects, ultra-fast laser technology has gradually been applied to the processing of shaped screen. It retains all the advantages of traditional laser processing, while minimizing the adverse effects of high temperature on the finished product. As the pulse width of ultra-fast lasers is further narrowed, meaning higher peaks and lower thermal effects, less energy is required to complete the screen cutting process at higher peak powers, thus minimizing the thermal effects on the glass.
Nowadays, many companies are putting attention in the direction of ultra-fast laser, and the new processing needs represented by shaped screens are pushing laser technology to usher in new breakthroughs.