Why does the LCD panel require such precise cleaning?

The cleaning of LCD panels is one of the most crucial and demanding steps in the manufacturing process. This is because it mainly occurs after the LCD boxes are manufactured, and during this stage, a large amount of contaminants are introduced.

Pre-pour contamination: Before injecting the liquid crystal material into the liquid crystal box, the box needs to be evacuated. During this process, the liquid crystal may splash onto other areas of the glass substrate due to the rupture of bubbles.

Residual substances during infusion: During the infusion process, the liquid crystal material inevitably comes into contact with the substrate, resulting in the presence of liquid crystals on the glass surface or in the connection gaps.

Shavings after grinding: After the pouring process is completed, in order to install the driving IC and the FPC flexible wiring, it is necessary to grind and chamfer the glass edges. This will generate a large amount of tiny glass shavings, which will embed or adhere to the glass gaps.

The necessity of precision: The LCD substrate is covered with micron-level fine lines and transistors. Any tiny particle or remaining liquid crystal could cause fatal defects. Therefore, an ultrasonic cleaning technology that can achieve "precise cleaning" must be adopted to meet the extremely high cleanliness standards.

The detailed process flow of the VIGOTT optical ultrasonic cleaning machine:

The cleaning of liquid crystal panels is usually carried out on an automated assembly line, with multiple tanks performing segmented operations to achieve efficient and thorough cleaning and drying. A typical process consists of 11 or more stations, and the process is as follows:

Loading and initial washing:

Loading: Place the LCD chips to be cleaned into the cleaning basket.

Water-based cleaning agent ultrasonic cleaning 1: Use alkaline or neutral water-based cleaning agent and combine it with ultrasonic waves for initial cleaning to remove most of the oil stains and particles.

Main cleaning and rinsing:

Water-based cleaning agent ultrasonic cleaning 2: The second cleaning process to ensure the initial cleaning effect.

DI water spray cleaning: Use high-purity deionized water (DI water) for high-pressure spraying to remove residual cleaning agents and loosened contaminants.

Pure water ultrasonic rinsing (multiple times): Ultrasonic rinsing is carried out in several separate pure water tanks, usually 4 or more times. These tanks operate in a recycling manner, ensuring clean water quality while saving water.

Dehydration and Drying:

Slow lifting dehydration: Lift the liquid crystal sheet slowly from pure water. This process utilizes the surface tension of water, effectively removing large water droplets adhering to the substrate surface. Preventing water stains from forming.

Hot air drying (multiple times): Usually, two cycles of hot air drying are carried out. The air passes through an efficient filter for purification, ensuring thorough drying of the glass without introducing new contaminants.

Discharging: After the cleaning and drying processes, the liquid crystal sheets can proceed to the next step.