What are the causes that lead to V-shaped distortion in LCD screens？
The display anomaly of a "V-shaped block" or "V-shaped" on the LCD screen is a very typical fault phenomenon. I...
The display anomaly of a "V-shaped block" or "V-shaped" on the LCD screen is a very typical fault phenomenon. It usually points to a more specific hardware issue than a bright line.
The "V-shaped" defect typically manifests as color anomalies, bright spots, dark spots, flickering, or converging lines in a specific area of the screen (which may take the shape of a V, fan, triangle, or rectangle).
Here are several main reasons leading to this malfunction:
1.Screen driver circuit or connection issues (most common cause)
This is the main cause of the "V block" malfunction, which lies in the "command center" and "communication line" displayed on the control screen.
Source driver chip malfunction or virtual soldering
This is the most likely culprit.
Principle: The driving circuit of a LCD screen usually consists of a "source driving circuit" and a "gate driving circuit", which act as a coordinate axis and jointly control the switching of each pixel point. The source driver chip is responsible for signals in the vertical direction. These chips are usually directly bonded to the flexible ribbon of the screen through a process called "COF".
Why is it a "V block": A screen is usually controlled by multiple source driver chips for partitioning. When one of the chips is damaged, poorly soldered, or the wiring connecting it breaks, the entire vertical area it is responsible for controlling will malfunction. Due to the distribution of screen signals, the boundary of this malfunctioning area sometimes exhibits a V-shaped or fan-shaped diffusion effect, rather than a straight line.
Characteristics: The boundary of the fault area may be blurry, and there may be colored vertical lines, flickering, or a completely black/white screen inside.
Poor contact of screen cable (TCP/COF) binding point
The "hot press bonding point" connecting the driver chip and the glass substrate may oxidize or loosen due to vibration, moisture, or process defects. This binding point precisely controls a certain area of the screen, and its failure will cause abnormal display in that area, forming a V block.
2. Physical damage
Although not as direct as bright lines, specific physical damage may also cause such problems.
Localized compression or impact
If the impact point happens to be at a specific position on the screen border and the impact force is transmitted in, it may damage the driver chip or wiring connection point responsible for that area, resulting in a regional fault rather than a single line.
A sharp object hitting a certain point on the screen may cause a local circuit short or open circuit, affecting the display of an area.
Internal foreign objects
During assembly or maintenance, if small foreign objects (such as dust, metal debris) fall on the driver chip or critical connection lines, long-term use may cause local short circuits and form V blocks.
3. Defects in the manufacturing of the screen itself
Defects in the driver chip or binding process
During the production process, the bonding quality of a certain source driver chip is not up to standard, with the potential for virtual soldering or internal damage. At the beginning, it may not appear, but with the thermal expansion and contraction during use, the problem gradually exposes and eventually forms a V block.
Summary and fault diagnosis:
Fault phenomenon | The most likely reason | Difficulty and Suggestions for Maintenance |
Fixed V-shaped/fan-shaped color blocks or dark blocks, with blurred boundaries and possible thin vertical lines inside. | The source driver chip is damaged or there is a fault in the related wiring binding point. | The maintenance difficulty is extremely high. Almost impossible to solve through simple repairs. Because it requires the replacement or rebinding of driver chips, which requires precise hot press bonding equipment and technology, and the success rate is not high. |
Sometimes there is no V-block, tapping the body or pressing the border may cause changes. | Poor contact at the binding point of the driver chip or cable. | There is a possibility of repair, but it is still difficult. Perhaps the virtual solder joints are temporarily connected. But this situation is very unstable and usually develops into a permanent malfunction in the end. |
Sometimes there is no V-block, tapping the body or pressing the border may cause changes. | It may be due to unstable power supply or signal from the motherboard to the screen, but the more likely problem still lies in the screen driver end. | Need to investigate first. You can try connecting an external monitor. If the external connection is normal, the problem is locked in the screen itself or the screen cable. |
Simple troubleshooting that you can try
1. External monitor: Similar to a bright wire fault, this is the first step in identifying the source of the problem. If the external display is normal, 100% of the problem lies in the device's own screen, screen cable, or connection.
2. Gently press: When the device is turned off, gently press the back position corresponding to the screen border and "V block", and then turn it on to observe if there are any changes. Caution: Do not apply too much force to avoid causing greater damage.
3. Observe changes: Pay attention to whether the "V block" is fixed and unchanged, or whether it will increase, decrease, or change color with usage time and screen temperature.
Final recommendation: For regional faults such as "V block", the ultimate solution in most cases is to replace the entire screen assembly. Because it involves the most core and precise driving components of the screen, maintenance costs and risks are much higher than replacement.
