OLED Resonator Length Adjustment for Color Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic electroluminescence displays face issues with uneven light-emitting layer thickness due to vapor deposition, leading to variations in brightness and color hue, affecting image quality.
Innovation Solution
A display device design featuring a separate electroluminescence layer with distinct thinner and thicker portions, where the cap layer and hole transport layer include basis and adjustment layers to minimize color changes by adjusting resonator lengths at the central and edge portions of the contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If vapor deposition is used to form light-emitting layers, then the manufacturing process is simple and efficient, but the light-emitting layer thickness becomes uneven near mask openings, causing color hue variations
Solution Approach 1:
The patent applies local quality by creating different layer thicknesses in different regions. The light-emitting layer has a first thickness in the central region and a second thickness (different from the first) in the edge region near mask openings. This localized thickness variation compensates for the uneven deposition, ensuring uniform optical properties across the entire pixel area while maintaining the simplicity of vapor deposition manufacturing.
2Illumination intensity
If the light-emitting layer thickness is increased to improve brightness, then the brightness increases, but the resonator length changes, causing wavelength shifts and hue variations
Solution Approach 1:
The patent implements local quality by establishing different thickness relationships in different regions. The light-emitting layer is designed with a first thickness in the central region and a second thickness in the edge region, where the second thickness is specifically controlled to be thinner than the first thickness. This localized thickness differentiation allows the resonator length to be optimized in each region, ensuring that wavelengths of constructive interference remain consistent across the pixel area while maintaining high brightness.
3Ease of manufacture
If a uniform thickness light-emitting layer is formed, then the manufacturing process is simple, but the edge portions near mask openings have reduced adhesion, causing thickness variations
Solution Approach 1:
The patent applies local quality by creating region-specific thickness characteristics. The light-emitting layer is designed with a first thickness in the central region and a second thickness in the edge region near mask openings. This localized thickness variation compensates for the adhesion deficiency at edge portions, ensuring uniform optical properties across the pixel area while maintaining the simplicity of vapor deposition manufacturing.
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 design minimizes changes in emission color by effectively adjusting resonator lengths, maintaining consistent chromaticity coordinates across the display area, thereby enhancing image quality.
Implementation Method 1
An organic electroluminescence display may have light-emitting layers different in color for respective pixels
Implementation Method 2
With an optical resonance device in a structure, resonator lengths vary due to difference in thickness of the light-emitting layers, and wavelengths of constructive interference vary, thereby changing hues of light
Data Source
AI summary
The first surface includes a contact area in contact with one of the pixel electrodes. The electroluminescence layer includes a separate layer, the separate layer having sections separated from each other. The separate layer at each of the sections has a first portion and a second portion thinner than the first portion, the first portion overlapping with a central portion of the contact area, the second portion overlapping with an edge portion of the contact area. At least one of the electroluminescence layer and the cap layer has a basis layer and an adjustment layer overlapping with each other, the basis layer continuously overlapping with the first portion and the second portion, the adjustment layer overlapping with the second portion without overlapping with a part of the first portion.