Subpixel Bank Layout for Uniform Current Density in Displays
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Solution Overview
Problem
Current display devices face challenges in achieving uniform current density across sub-pixels, leading to inefficiencies and potential physical damage due to varying current magnitudes and heat generation, which affects the performance and longevity of light emitting elements.
Innovation Solution
The display device incorporates a substrate with distinct light emitting areas and banks, where the size and number of light emitting elements are optimized to ensure uniform current density by varying the size and number of elements in each area, and adjusting current magnitudes to minimize heat-induced deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform bank sizes are used for all sub-pixels, then manufacturing is simplified, but current density becomes non-uniform leading to reduced reliability
Solution Approach 1:
The patent applies local quality by making the bank sizes non-uniform across different sub-pixels. Specifically, the first bank (for first color sub-pixel) has a first size, the second bank (for second color sub-pixel) has a second size different from the first size, and the third bank (for third color sub-pixel) has a third size different from both. This local differentiation compensates for variations in light emission characteristics of different colored sub-pixels, achieving uniform current density across all sub-pixels while maintaining manufacturing feasibility through a systematic sizing approach.
2Illumination intensity
If larger current magnitudes are applied to compensate for lower efficiency sub-pixels, then brightness uniformity improves, but heat generation increases causing physical damage
Solution Approach 1:
The patent applies parameter changes by systematically varying the bank sizes (first size, second size, third size) to match the different current density requirements of various colored sub-pixels. This geometric parameter adjustment allows each sub-pixel to receive an optimized current magnitude that achieves uniform brightness without excessive current overcompensation. The differentiated bank structures enable precise control of current distribution, reducing heat generation while maintaining brightness uniformity across all sub-pixels.
Data Source
AI summary
A display device includes a substrate including a first light emitting area, a second light emitting area, and a third light emitting area; first banks spaced apart from each other on the substrate; first electrodes and second electrodes disposed on the first bank, covering the first bank, and spaced apart from each other; light emitting elements respectively disposed on the first electrodes and the second electrodes; and second banks respectively disposed on the first electrodes and the second electrodes, the second banks include a second-first bank defining the first light emitting area, a second-second bank defining the second light emitting area, and a second-third bank defining the third light emitting area, and a size of the second-first bank, a size of the second-second bank, and a size of the second-third bank are different from each other in a plan view.