1. Principle: Previously, it was written that screen brightness is directly proportional to (ELVDD-data). ELVDD is typically fixed at 4.6V, which means it is directly proportional to (4.6V-data). What is data? Actually, data refers to the voltage corresponding to the displayed grayscale level, or in simpler terms, the content displayed on the screen.

2. Causes of vertical lines: The screen writes the "voltage corresponding to the screen display content" into the backplane row by row. The grayscale data voltage corresponding to these pixels in the "column direction" all enter through a common "line in the column direction".

2-1) If there is a problem with this line in the column direction, the data voltage for the entire column cannot be written or the written voltage is relatively low, resulting in a corresponding bright line (ELVDD-data).

2-2) This charging line in the column direction is driven by the chip, passing through the bending area on the panel, and then reaching the pixel area on the panel. Any issues with these three sections may cause the appearance of bright lines.

2-3) It refers to the "corrosion" phenomenon observed during the repair of a mobile phone by a netizen. This corrosion occurs on this specific circuit path.

2-4) Many users operate their phones in harsh environments, such as high humidity and high temperature areas, where this issue is relatively more prevalent. Of course, poor waterproofing of some screens is also a factor to consider.

3. Solutions

3-1) The repair experts have also devised two repair methods: heating with a hair dryer or lighter, or striking with static electricity. This method is not recommended, as it is only suitable for cases where the corrosion is not completely thorough. It involves a greater element of chance, and there is a high risk of recurrence in the future, so there is no need to spend this unnecessary money.

3-2) The correct approach: Contact the official after-sales service and provide proof of purchase or similar documentation. All phones come with a warranty period, and responsible manufacturers will offer free screen replacement services, even beyond the warranty period. Some manufacturers may charge a fee, but the screen replacement is definitely more reliable than the above method of taking a chance on repairs.