Pixel Electrode Height Difference Blocks Light Path
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Solution Overview
Problem
Self-light emitting display devices face issues with light-induced degradation of transistors due to light emitted from adjacent pixels, which affects display quality and longevity.
Innovation Solution
The display device incorporates a via layer with a crest and valley structure, where the pixel electrodes are positioned such that one end of each electrode is on the valley, minimizing light incidence on transistors and reducing light-induced degradation by blocking the light path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pixel electrodes are positioned at the same height level, then manufacturing process is simplified, but light from adjacent pixels directly reaches transistors causing light-induced degradation
Solution Approach 1:
The patent introduces a height dimension difference between pixel electrodes, positioning the first pixel electrode at a first height and the second pixel electrode at a second height. This vertical dimensional change creates a height difference that blocks light paths from adjacent pixels reaching the transistor, thereby preventing light-induced degradation while maintaining manufacturing feasibility through controlled via layer thickness variations.
Solution Approach 2:
The via layer serves as an intermediary structure with different thicknesses (first via layer thickness and second via layer thickness) that creates the height difference between pixel electrodes. This intermediary structure effectively blocks light paths without requiring additional light-blocking layers or complex shielding mechanisms, solving the contradiction between manufacturing simplicity and transistor protection.
2Reliability
If multiple masks and layers are used for circuit layer formation, then transistor protection from light is improved, but process efficiency decreases
Solution Approach 1:
The via layer performs multiple functions: it provides electrical connection (original function) and simultaneously creates height difference for light blocking (additional function). By making the via layer multi-functional, the patent achieves transistor protection without adding separate light-blocking layers or increasing the number of masks, thereby maintaining process efficiency while improving reliability.
Solution Approach 2:
The patent merges the light-blocking function with the existing via layer structure by varying its thickness in different regions. Instead of adding separate protective layers or using additional masks, the via layer is designed with first and second different thicknesses to simultaneously achieve electrical connection and light path blocking, consolidating multiple functions into a single structure.
Data Source
AI summary
A display device includes a first pixel and a second pixel. The first pixel and the second pixel each includes a first transistor, a portion of a via layer disposed on the first transistor, and a portion of a first metal layer disposed on the via layer. The first pixel and the second pixel further include a first pixel electrode and a second pixel electrode disposed in the first metal layer, and a first end of the first pixel electrode faces the second pixel electrode and is positioned at a height lower than the second pixel electrode.