Electrochromic Layer for OLED Cross-Talk Reduction
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Solution Overview
Problem
OLED display devices face low gray scale cross-talk due to uneven current distribution among blue, green, and red pixels, leading to poor display uniformity and brightness.
Innovation Solution
A display substrate with an electrochromic functional layer positioned between the light-emitting device layer and the substrate, which absorbs or refracts light from non-driven pixels to reduce cross-talk, using an electrochromic layer that changes its state under electrical control to manage light transmission and absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a large voltage is applied to blue organic light-emitting material to increase its brightness, then the blue pixel luminance is improved, but current flows to green and red pixels causing low gray scale cross talk
Solution Approach 1:
An electrochromic functional layer is introduced as an intermediary between the light-emitting device layer and the substrate. This layer selectively absorbs or blocks light from non-driven pixels (green and red pixels when blue is driven) to prevent cross-talk, while allowing light from the driven blue pixel to pass through effectively.
Solution Approach 2:
The electrochromic functional layer is positioned specifically at regions where cross-talk occurs (overlapping with effective light-emitting areas of adjacent pixels). The layer exhibits different optical properties (absorption vs. transmission) in different spatial locations based on the driving state of underlying pixels, achieving local optimization of light management.
2Reliability
If an electrochromic functional layer is added to reduce cross-talk, then display uniformity is improved, but device structure becomes more complex
Solution Approach 1:
The electrochromic functional layer serves multiple functions simultaneously: it acts as a cross-talk suppression layer by absorbing light from non-driven pixels, and as a controllable optical modulator that switches between absorbing and transparent states based on applied voltage. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The electrochromic functional layer is merged with the existing OLED structure by positioning it between the light-emitting device layer and the substrate. The layer shares the same substrate and is integrated into the existing pixel architecture, minimizing structural disruption while adding cross-talk suppression capability.
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
Improves display uniformity by minimizing low gray scale cross-talk between adjacent pixels, enhancing the overall brightness and clarity of the display panel without affecting normal light emission.
Implementation Method 1
an electrochromic functional layer positioned between the light-emitting device layer and the substrate, which absorbs or refracts light from non-driven pixels to reduce cross-talk
Implementation Method 2
an electrochromic functional layer positioned between the light-emitting device layer and the substrate, which absorbs or refracts light from non-driven pixels to reduce cross-talk
Data Source
AI summary
A display substrate, a method of forming a display substrate and a display device are provided. The display substrate includes: a plurality of pixel units arranged in an array, a substrate, a light-emitting device layer and an electrochromic functional layer, where the light-emitting device layer and the electrochromic functional layer are stacked on the substrate; the light-emitting device layer includes a plurality of light-emitting devices, an orthographic projection of the electrochromic functional device on the substrate is at least partially overlapped with an orthographic projection of the corresponding effective light-emitting area on the substrate.