OLED Reflective Electrode Laser Modification for Contrast
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Solution Overview
Problem
Organic light-emitting display apparatuses face a decrease in contrast due to external light reflection from metal electrodes and wirings, which is typically addressed by using expensive polarization plates or complex black matrix formations.
Innovation Solution
The solution involves forming an optical property modification layer on the surface of reflective electrodes using a femtosecond duration laser beam pulse, reducing reflectivity and enhancing light absorption, and incorporating a light-blocking layer and transparent interference layers to minimize external light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polarization plate is used to minimize contrast decrease, then contrast is improved, but cost increases and transmittivity decreases
Solution Approach 1:
The patent replaces the expensive polarization plate with a low-cost optical property modification layer formed by laser treatment on the reflective electrode. This layer provides the necessary optical functionality at a fraction of the cost of polarization plates, while being integrated into the existing electrode structure without requiring additional consumable components.
Solution Approach 2:
The patent modifies the optical properties of the reflective electrode surface through femtosecond laser irradiation, changing parameters such as surface roughness, reflectivity, and light scattering characteristics. This parameter modification achieves the contrast enhancement function previously requiring a polarization plate, while allowing light transmission that would be blocked by polarizing filters.
2Reliability
If a polarization plate is used to minimize contrast decrease, then contrast is improved, but luminance decreases due to light blocking
Solution Approach 1:
The laser treatment modifies the optical parameters of the reflective electrode surface to achieve selective light interaction. The surface is engineered to scatter and absorb external ambient light while maintaining high transmission for the forward-emitted display light, thus improving contrast without sacrificing luminance. This is achieved by controlling surface morphology and optical constants through precise laser parameter adjustment.
Solution Approach 2:
The optical property modification is applied selectively to specific regions of the reflective electrode, creating localized areas with enhanced light scattering and absorption properties. This local modification ensures that the contrast enhancement effect is concentrated where needed (at the electrode surface facing external light sources) while minimizing impact on the overall light transmission and luminance of the display.
3Reliability
If a black matrix is formed to minimize contrast decrease, then contrast is improved, but manufacturing complexity increases due to additional mask process
Solution Approach 1:
The patent combines the reflective electrode function with the contrast enhancement function by integrating the optical property modification layer directly onto the electrode surface. This merging eliminates the need for a separate black matrix layer and its associated mask alignment process, reducing manufacturing complexity while achieving the same contrast improvement effect. The electrode serves dual purposes: electrical conduction and optical management.
Solution Approach 2:
The femtosecond laser treatment directly modifies the physical and optical parameters of the reflective electrode surface in situ, creating the contrast-enhancing structure during or after electrode formation. This parameter modification approach eliminates the need for additional patterning steps, mask alignment, and black matrix deposition processes, thereby simplifying the manufacturing workflow while achieving superior contrast performance.
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 enhances contrast without the need for additional elements like polarization plates or complex mask processes, effectively reducing external light reflection and improving display performance.
Implementation Method 1
The optical property modification layer may be formed by applying a femtosecond duration laser beam pulse at least once to the reflective electrode
Implementation Method 2
The optical property modification layer may have a higher light absorption ratio than the reflective electrode
Implementation Method 3
the contrast of the organic light-emitting display apparatus may decrease due to the reflection of the external light by a metal constituting electrodes and wirings in the display apparatus
Data Source
AI summary
An organic light-emitting display apparatus including: a first substrate; a second substrate disposed to face the first substrate; a first electrode disposed between the first substrate and the second substrate and a second electrode disposed to face the first electrode; and an organic light-emitting layer disposed between the first electrode and the second electrode, wherein at least one of the first electrode and the second electrode is a reflective electrode, and an optical property modification layer having at least one optical property modified from that of the reflective electrode is formed on a surface of the reflective layer.