Textured Reflective Electrodes for Display Light Extraction
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Solution Overview
Problem
Existing display devices face challenges in achieving high light emission efficiency due to the formation of optical waveguides that trap light within the layers, reducing the amount of light emitted externally.
Innovation Solution
The display device incorporates reflective electrodes with textured surfaces and a refractive index-mismatched insulating layer to diffuse light, altering its travel direction and reducing waveguide formation, thereby enhancing light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If smooth reflective electrodes are used, then device structure is simple and manufacturing is easy, but light emission efficiency is reduced due to optical waveguide formation
Solution Approach 1:
The patent changes the surface parameter of the reflective electrodes from smooth to textured/irregular. This parameter change disrupts the optical waveguide effect by scattering light at the electrode surface, preventing total internal reflection and improving light extraction efficiency without fundamentally changing the device structure or manufacturing process
Solution Approach 2:
The patent introduces a composite structure combining reflective electrodes with textured surfaces and insulating layers having different refractive indices. This composite approach creates multiple interfaces that scatter and redirect light, reducing waveguide formation while maintaining the reflective function of the electrodes
2Ease of manufacture
If uniform insulating layers are used, then manufacturing is simple, but light emission efficiency is reduced due to waveguide light trapping
Solution Approach 1:
The patent changes the refractive index parameter of the insulating layer to be different from that of the contact electrodes. This refractive index mismatch creates optical interfaces that scatter light and prevent waveguide formation, improving light extraction while maintaining manufacturing simplicity through standard layer deposition processes
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 increases the amount of light emitted externally by diffusing light travel directions through textured electrodes and insulating layers, improving overall light emission efficiency.
Implementation Method 1
The first reflective electrode may include first surface irregularities disposed on a top surface of the first reflective electrode. The second reflective electrode may include second surface irregularities disposed on a top surface of the second reflective electrode.
Implementation Method 2
A refractive index of the second insulating layer may be different from a refractive index of the first contact electrode and different from a refractive index of the second contact electrode.
Data Source
AI summary
A display device includes a first reflective electrode disposed on a surface of a substrate, a second reflective electrode spaced apart from the first reflective electrode and disposed on the surface of the substrate, and a light emitting element disposed between the first reflective electrode and the second reflective electrode. The first reflective electrode includes first surface irregularities disposed on a top surface of the first reflective electrode. The second reflective electrode includes second surface irregularities disposed on a top surface of the second reflective electrode.