Optical Path Length Adjustment Films for Display Devices
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Solution Overview
Problem
In organic electroluminescence (EL) display devices, achieving optimal light emitting efficiency for each color is challenging due to the difficulty in patterning optical path length adjusting films with different refractive indices to match the unique film thickness requirements for red, green, and blue light emitting elements, especially as display resolution increases.
Innovation Solution
The optical path length adjusting films with high and low refractive indices are divided into multiple patterns and strategically overlapped across light emitting elements of different colors, allowing for optimized film thickness distribution without the need for precise masking, thereby enhancing light emitting efficiency for each color.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If optical path length adjusting films with different refractive indices are patterned to match unique film thickness requirements for each color, then light emitting efficiency for each color is improved, but manufacturing complexity and difficulty increase significantly
Solution Approach 1:
The patent divides the optical path length adjusting film into multiple regions with different film thicknesses corresponding to different color light emitting elements. By segmenting the film into first, second, and third regions with progressively decreasing thicknesses, the patent achieves color-specific optical optimization without requiring separate patterning processes for each color, thus improving light emitting efficiency while reducing manufacturing complexity.
Solution Approach 2:
The patent applies different film thicknesses to different regions of the optical path length adjusting film to match the specific optical requirements of each color. The first region has a first film thickness for red light, the second region has a second film thickness for green light, and the third region has a third film thickness for blue light, ensuring each color receives optimal optical path length adjustment locally.
2Measurement precision
If display resolution is increased to achieve high-definition displays, then image quality is improved, but the difficulty of patterning optical path length adjusting films increases
Solution Approach 1:
The patent segments the optical path length adjusting film into distinct regions that can be formed using standard photolithography processes without requiring ultra-fine patterning. By defining regions based on color zones rather than individual pixel structures, the patent maintains manufacturing feasibility while supporting high-definition displays with improved resolution.
Solution Approach 2:
The patent transitions from two-dimensional pixel-level patterning to a three-dimensional approach by varying film thickness in the vertical dimension. This allows optical optimization to be achieved through thickness modulation rather than lateral patterning, thereby maintaining manufacturing precision even as display resolution increases.
3Productivity
If multiple optical path length adjustment films with different refractive indices are stacked, then optical performance is improved, but device structure becomes more complex
Solution Approach 1:
The patent implements a single optical path length adjusting film with locally varied thickness rather than multiple stacked films. The film thickness is optimized locally for each color region, eliminating the need for complex multi-layer stacking while achieving the same optical performance benefits.
Solution Approach 2:
The patent combines the functions of multiple optical path length adjustment films into a single integrated film structure. By merging the thickness control function into one film with spatially varying thickness, the patent simplifies the device structure while maintaining the optical performance that would otherwise require multiple stacked films.
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 approach improves light emitting efficiency and color purity by ensuring that each color's light emitting element receives the appropriate optical path length adjustment, even in high-definition displays where precise patterning becomes difficult.
Implementation Method 1
a first optical path length adjustment film having a first refractive index and a second optical path length adjustment film having a second refractive index different from the first refractive index
Data Source
AI summary
A display device includes a display region arranged above a substrate, a first light emitting element emitting light of a first color, a second light emitting element emitting light of a second color, and a third light emitting element emitting light of a third color arranged in the display region, and a first optical path length adjustment film, a second optical path length adjustment film, and a third optical path length adjustment film in the display region.