Perforated OLED Screen Structure for Under-Display Camera Light Leakage
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Solution Overview
Problem
Perforated screens in OLED displays suffer from light leakage, which interferes with camera shooting effects due to lateral light transmission through film layers, particularly as screen-to-body ratios increase.
Innovation Solution
A perforated display screen design featuring a base substrate with a first hole region, an array substrate layer with a second hole region, an encapsulation layer with a third hole region, and a touch layer with a fourth hole region, stacked and perforated in sequence, with a black photoresist unit covering the hole walls to block lateral light leakage. This design reduces film thickness above the light emitting layer and minimizes hole diameter by etching inorganic film layers before perforation, thereby reducing stress and light leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a perforated screen is used to increase screen-to-body ratio, then the screen-to-body ratio is improved, but light leakage from the side of the screen occurs which interferes with camera shooting
Solution Approach 1:
The patent applies different treatments to different parts of the hole structure: the inner wall of the hole is coated with black photoresist to block light, while the top surface maintains optical clarity. This local differentiation allows the hole to serve dual functions - structural perforation for screen-to-body ratio improvement while simultaneously blocking lateral light leakage through the black coating on the inner walls.
Solution Approach 2:
The black photoresist acts as an intermediary substance that blocks light between the hole structure and the camera sensor. By introducing this intermediate layer on the inner wall of the hole, the patent prevents direct light transmission from the OLED through the hole to the camera, thereby solving the light leakage problem while maintaining the perforated screen design.
2Object-generated harmful factors
If the hole diameter is reduced to minimize light leakage, then light leakage is reduced, but the stress concentration increases which may cause cracking
Solution Approach 1:
The patent performs etching of the inorganic film layers before creating the final hole perforation. This preliminary action of removing inorganic materials in advance creates a more compliant structure that can better accommodate the stress concentration around smaller diameter holes, reducing the risk of cracking while maintaining minimal light leakage through the smaller aperture.
Solution Approach 2:
The patent changes the physical and chemical parameters of the film layers by etching away inorganic materials, transforming the structure from a rigid multi-layer composition to a more flexible configuration that can handle stress concentration. This parameter change allows the use of smaller hole diameters without compromising structural integrity.
Data Source
AI summary
A pixel driving circuit and a display panel are provided. The pixel driving circuit includes a control unit to output a control signal by detecting a voltage difference between two opposite ends of a sampling resistor, and to turn on a fourth switch by the control signal. When the fourth switch is turned on, a second positive voltage received by the pixel driving circuit charges a second node to further speed up a voltage pulling up of the second node to improve a detecting speed of the pixel driving circuit.