Filling Layer for OLED Panel Segment Difference
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Solution Overview
Problem
The segment difference between the display area and non-display area in organic light-emitting display panels, caused by different layer arrangements, leads to manufacturing issues such as cracking or film breakage during the process of forming signal lines or films, due to inconsistencies in the thickness of photoresist layers.
Innovation Solution
Incorporating a filling layer in the non-display area with a material matching that of the microlens array or refractive index matching layer, which extends from the display area, to fill the segment difference and facilitate continuous layer formation, thereby simplifying the manufacturing process and preventing breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If layers are only provided in the display area, then the device structure is simplified, but segment difference between display area and non-display area causes cracking or film breakage during manufacturing
Solution Approach 1:
The patent divides the display panel into display area and non-display area with distinct layer configurations. The display area contains complete layers (anode, hole transport layer, light-emitting layer, electron transport layer, cathode) while the non-display area has reduced layers, creating segmented functional zones that optimize both complexity and reliability for each region.
Solution Approach 2:
Different layer structures are applied to different regions: the display area uses full layers for light emission functionality, while the non-display area uses reduced layers for signal transmission. This local differentiation allows each region to have optimal structure for its specific function, resolving the contradiction between overall simplicity and manufacturing reliability.
2Ease of manufacture
If photoresist thickness varies between display area and non-display area, then manufacturing process is simplified, but exposure process cannot completely cure photoresist in non-display area leading to etching defects
Solution Approach 1:
The patent applies a protective layer over the photoresist in the non-display area before the exposure process. This preliminary protective action prevents the photoresist from being completely cured during exposure, ensuring that subsequent etching processes can be properly controlled and preventing etching defects in the signal line regions.
Solution Approach 2:
A protective layer is introduced as an intermediary between the photoresist and the exposure/etching processes in the non-display area. This intermediary layer controls the exposure depth, allowing the photoresist to remain partially uncured so that etching can be precisely controlled without damaging the signal line structures.
3Adaptability or versatility
If signal lines cross from display area to non-display area, then device functionality is achieved, but thickness difference of photoresist causes incomplete curing and etching away of signal lines
Solution Approach 1:
The patent applies different photoresist thicknesses and protective measures to different regions: the display area uses standard photoresist thickness for pixel patterning, while the non-display area uses adjusted thickness with protective layers to preserve signal line integrity during etching processes.
Solution Approach 2:
A protective layer is introduced as an intermediary in the non-display area to control the etching process. This protective layer prevents over-etching of signal lines that cross from the display area, ensuring that the signal lines maintain their integrity while still allowing proper patterning in the display area.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The filling layer ensures a continuous structure across the display and non-display areas, improving manufacturing yield and preventing light leakage by matching refractive indices, thus enhancing the reliability and efficiency of the organic light-emitting display panel.
Implementation Method 1
a microlens array layer located at a side of the organic light-emitting layer close to a light-exiting surface... a refractive index matching layer located at a side of the microlens array layer close to the light-exiting surface... the refractive index matching layer has a refractive index greater than a refractive index of the microlens array layer
Data Source
AI summary
Provided is an organic light-emitting display panel, including: a thin film transistor layer provided in a display area; an organic light-emitting layer provided in the display area and including light-emitting pixels; a microlens array layer provided in the display area and including microlenses corresponding to the light-emitting pixels; a refractive index matching layer provided in the display area; and a filling layer provided in the non-display area. The refractive index matching layer and the microlens array layer have different refractive indexes. Each microlens includes a first surface that is in contact with the refractive index matching layer. The first surface is a curved surface protruding towards one of the microlens array layer and the refractive index matching layer, which has a smaller refractive index. A material of the filling layer is same as at least one of materials of the microlens array layer and the refractive index matching layer.