OLED Backplane Through-Hole Slope Optimization
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Solution Overview
Problem
In OLED display backplanes, the steep slope of the first through hole in the protective layer leads to breakage between the anode of the light-emitting element and the source or drain electrode, causing overheating and screen burn due to the limitations of exposure equipment and resulting in a short service life.
Innovation Solution
The design includes a first through hole in the protective layer and a second through hole in the planarization layer, both with inclined sidewalls, where the second through hole covers the first and has a larger area, with a gentle slope to reduce breakage risk, and a step-like structure is formed to facilitate a simpler manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the first through hole is formed with a steep slope due to exposure equipment limitations, then the manufacturing process is simpler, but breakage occurs between the anode and source/drain electrode causing overheating and screen burn
Solution Approach 1:
The through-hole structure is divided into two separate through-holes: a first through-hole in the protective layer and a second through-hole in the planarization layer. This segmentation allows each through-hole to have optimized sidewall slopes independent of the other, enabling the first through-hole to have a gentler slope that prevents breakage while maintaining manufacturing feasibility.
Solution Approach 2:
Different regions of the through-hole structure are given different local qualities: the first through-hole has a gentler sidewall slope suitable for preventing breakage at the anode connection point, while the second through-hole can have different characteristics optimized for its position in the planarization layer. This local optimization resolves the conflict between manufacturing simplicity and connection reliability.
2Reliability
If the sidewall of the first through hole is made gentle to reduce breakage risk, then the connection reliability improves, but the exposure process becomes more difficult
Solution Approach 1:
By segmenting the through-hole into two separate structures, the exposure process can be optimized for each individually. The first through-hole uses a gentler slope that is easier to expose without causing breakage, while the second through-hole compensates for any exposure difficulties, thereby improving connection reliability without excessively complicating the overall manufacturing process.
Solution Approach 2:
The solution moves from a single vertical dimension (one through-hole depth) to a two-dimensional approach (two through-holes at different depths and positions). The second through-hole's orthographic projection covers the first through-hole's projection, creating a stepped configuration that distributes the exposure complexity across multiple dimensions rather than concentrating it in one deep hole.
3Device complexity
If a single through hole is used to connect the source/drain electrode to the anode, then the structure is simpler, but the steep slope causes breakage and overheating
Solution Approach 1:
The single through-hole is segmented into two separate through-holes: the first through-hole in the protective layer and the second through-hole in the planarization layer. This segmentation allows the connection path to be distributed across two shallower structures with gentler slopes, preventing the breakage that occurs in a single steep-sided through-hole while maintaining reasonable structural complexity.
Solution Approach 2:
The first through-hole is nested within the projection area of the second through-hole, creating a stepped, nested configuration. The orthographic projection of the second through-hole covers the first through-hole's projection, with the contour lines partially overlapping. This nested arrangement creates a cascading structure that reduces slope angles and prevents breakage.
Data Source
AI summary
A display backplane, a manufacturing method thereof, and a display device are provided. The display backplane includes a base substrate. A thin film transistor array layer, a protective layer, a planarization layer, and a light-emitting element are arranged on the base substrate. A first through hole is formed in the protective layer, and a second through hole is formed in the planarization layer. The first through hole and the second through hole are connected. A source electrode or a drain electrode is electrically connected to an anode via the first through hole and the second through hole. Each of the first through hole and the second through hole has a sidewall inclined relative to the base substrate.