Color Filter Layer Design for OLED Chromaticity and Luminance
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Solution Overview
Problem
Organic electroluminescence display devices experience chromaticity changes when viewed from different angles due to differences in light emission characteristics between the central and peripheral areas of sub-pixels, leading to reduced luminance when attempting to mitigate these changes with light shielding or color filters.
Innovation Solution
A display device design featuring a color filter layer with filter openings at the center, overlapping light emitting layers of different colors, and positioned obliquely over the peripheral areas, which minimizes chromaticity changes and maintains luminance by matching transmitted light colors with the light emitting colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a light shielding layer is provided to cover the peripheral edge part of each sub-pixel, then chromaticity change is reduced, but luminance deteriorates
Solution Approach 1:
The color filter layer is designed with spatially varying properties: filter openings are provided at the central area where light emission is strongest, while the peripheral area has continuous filter material. This local differentiation allows the central area to maintain high luminance while the peripheral area corrects chromaticity variations, resolving the contradiction between luminance and chromaticity consistency.
Solution Approach 2:
The color filter layer is segmented into distinct functional zones: a central region with filter openings for high light transmission, and a peripheral region with continuous filter material for chromaticity correction. This segmentation allows each zone to perform its specific function optimally without compromising the other.
2Stability of the object's composition
If a color filter is arranged in the whole pixel, then chromaticity change is reduced, but luminance deteriorates due to spectral transmittance less than 100%
Solution Approach 1:
Instead of providing continuous color filter material across the entire pixel area, the invention applies color filter material only where necessary (peripheral areas) while leaving the central area open. This partial application maintains chromaticity consistency in the regions where it is needed without unnecessarily reducing luminance across the entire pixel.
Solution Approach 2:
The color filter layer implements local quality by providing different optical properties in different regions: the central area has high transmittance for maximum luminance, while the peripheral area has color filtering properties for chromaticity correction. This localized approach resolves the contradiction by applying filtering only where required.
3Stability of the object's composition
If the light emitting color is slightly different between peripheral edge part and central area of each sub-pixel, then display color uniformity deteriorates, but providing light shielding reduces luminance
Solution Approach 1:
The color filter layer is designed with spatially varying properties: filter openings are provided at the central area where light emission is strongest, while the peripheral area has continuous filter material. This local differentiation allows the central area to maintain high luminance while the peripheral area corrects chromaticity variations, resolving the contradiction between luminance and chromaticity consistency.
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
The solution effectively reduces chromaticity variations caused by visual field angles while maintaining light transmission, thereby enhancing display performance and preventing luminance deterioration.
Implementation Method 1
a color filter layer including a plurality of filter layers respectively overlapping one corresponding to the plurality of light emitting layers and provided on the common electrode, wherein the plurality of light emitting layers are divided into a plurality of groups in response to light emitting colors, and each of the plurality of groups includes one group corresponding to the plurality of light emitting layers, transmitted light colors of the plurality of filter layers are respectively the same type of colors as the light emitting colors of the plurality of light emitting layers
Implementation Method 2
an electroluminescence layer including a plurality of light emitting layers respectively overlapping the plurality of pixel electrodes, and including a plurality of contact areas respectively in contact with the plurality of pixel electrodes
Data Source
AI summary
A plurality of light emitting layers are divided into a plurality of groups in response to light emitting colors. Each of the plurality of groups includes a group corresponding to the plurality of light emitting layers. Transmitted light colors of a plurality of filter layers are respectively the same type of colors as the light emitting colors of the plurality of light emitting layers. Each of the plurality of light emitting layers includes a central area and a peripheral area having mutually different light emitting characteristics within a range corresponding to a plurality of contact areas. Each of the plurality of filter layers includes a filter opening at the center, and is provided at least obliquely upward in an outward direction of the peripheral area.