Electroluminescent Display Micro-Cavity Dielectric Thickness
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Solution Overview
Problem
Recent advancements in electroluminescent display devices have led to increased substrate sizes and high resolution, resulting in decreased pixel pitch, which has caused issues with optical efficiency degradation and color mixture.
Innovation Solution
The electroluminescent display device incorporates sub-pixel regions with varying dielectric layer thicknesses, a reflective electrode, an insulating pattern, and a micro-cavity structure to optimize light output and prevent color mixture, featuring a micro-cavity length that varies between blue, green, and red sub-pixel regions to enhance luminous efficiency and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pixel pitch is decreased to increase substrate size and resolution, then the display resolution is improved, but optical efficiency degrades and color mixture occurs
Solution Approach 1:
The patent applies local quality by creating different micro-cavity lengths in different sub-pixel regions (red, green, blue) through varying dielectric layer thicknesses. Each sub-pixel region has optimized local optical properties tailored to its specific wavelength requirements, allowing constructive interference for the intended color while preventing color mixture even as pixel pitch decreases.
Solution Approach 2:
The patent changes the optical parameters by adjusting the thickness of dielectric layers to create specific micro-cavity lengths for each sub-pixel. This parameter optimization enables constructive interference of output light at desired wavelengths, maintaining high optical efficiency despite reduced pixel pitch in high-resolution displays.
2Measurement precision
If the pixel pitch is decreased to increase substrate size and resolution, then the display resolution is improved, but color mixture occurs among sub-pixels
Solution Approach 1:
The patent implements local quality by assigning different micro-cavity lengths to different sub-pixel regions through varied dielectric layer thicknesses. This localized optimization ensures that each sub-pixel emits its intended color with constructive interference while preventing adjacent color leakage, thereby eliminating color mixture even at reduced pixel pitches.
Solution Approach 2:
The patent converts the potential harmful effect of reduced pixel pitch (which causes color mixture) into a benefit by using micro-cavity structures with different lengths for each sub-pixel. These structures create wavelength-specific constructive interference that enhances color purity and prevents mixing, turning the resolution increase into an opportunity for improved color performance.
3Loss of energy
If dielectric layers with different thicknesses are used to optimize luminous efficiency, then optical efficiency is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by varying dielectric layer thicknesses specifically in the micro-cavity regions of each sub-pixel while keeping other structural elements uniform. This localized differentiation optimizes luminous efficiency for each color without requiring complex changes throughout the entire device structure, thereby limiting the increase in overall device complexity.
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
This configuration optimizes luminous efficiency in each sub-pixel region, constructsively interferes output light, and prevents color mixture, thereby improving optical efficiency and reducing the size and weight of the optical system, particularly in head mount displays.
Implementation Method 1
constructsively interferes output light
Implementation Method 2
electroluminescent display device is a device in which electrical charge carriers are injected into a light-emitting layer formed between a cathode, which is an electron-injecting electrode, and an anode, which is a hole-injecting electrode, such that excitons are formed, and then radiative recombination of the excitons occurs, thereby emitting light
Implementation Method 3
a reflective electrode disposed on the passivation layer of each of the first, second, and third sub-pixel regions
Data Source
AI summary
An electroluminescent display device includes a substrate including first, second, and third sub-pixel regions; an interlayer insulating layer and a passivation layer each separately disposed at the first, second, and third sub-pixel regions on the substrate; a reflective electrode disposed on the passivation layer of each of the first, second, and third sub-pixel regions; first, second, and third dielectric layers disposed corresponding to the first, second, and third sub-pixel regions, respectively, on the reflective electrode; a first electrode disposed on each of the first, second, and third dielectric layers; an insulating pattern covering an edge of the first electrode; a light-emitting layer disposed on the first electrode and the insulating pattern and substantially all over the substrate including the first, second, and third sub-pixel regions; and a second electrode disposed on the light-emitting layer, wherein the first, second, and third dielectric layers have different thicknesses.