Reflective Layer for Display Device Light Extraction
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Solution Overview
Problem
Display devices face inefficiencies in emission efficiency and heat dissipation due to light emitted from light-emitting elements being lost in a downward direction, rather than being reflected and directed towards the viewer.
Innovation Solution
A reflective layer is strategically placed between a heat dissipation layer and light-emitting elements, utilizing optical layers with different refractive indices to reflect downward-traveling light back towards the display direction, and reflective patterns are selectively positioned to enhance emission efficiency and heat dissipation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light-emitting elements emit light in all directions, then the light output is maximized, but the emission efficiency towards the viewer is reduced due to light loss in downward direction
Solution Approach 1:
The patent converts the harmful downward-directed light that would otherwise be lost into a beneficial resource by using a reflective layer to redirect it toward the viewer. The reflective layer transforms wasted light energy into useful light output, improving emission efficiency without requiring additional light-emitting elements.
Solution Approach 2:
The patent introduces a vertical dimension solution by placing a reflective layer beneath the light-emitting elements. This allows light that travels downward (in the negative vertical direction) to be reflected upward (in the positive vertical direction), effectively utilizing the vertical space and redirecting light paths to improve viewer-facing emission.
2Productivity
If a reflective layer is added to improve emission efficiency, then light reflection is enhanced, but the device structure becomes more complex
Solution Approach 1:
The reflective layer serves multiple functions simultaneously: it reflects downward-directed light toward the viewer to improve emission efficiency, and it can be integrated with existing device layers without requiring separate complex structures. This multi-functionality reduces the need for additional dedicated components.
3Productivity
If reflective patterns are selectively arranged only in regions where downward light is incident, then emission efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies reflective patterns selectively only in specific regions where downward-directed light from the light-emitting elements is incident, rather than uniformly across the entire device. This localized application improves emission efficiency where needed while reducing material usage and simplifying manufacturing compared to full-coverage reflective layers.
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 improves emission efficiency by reflecting light emitted in a downward direction back towards the viewer and enhances heat dissipation, leading to improved performance in display devices.
Implementation Method 1
a reflective layer disposed between the functional layer and the second surface of the substrate, the reflective layer overlapping the at least one light-emitting element in a plan view
Implementation Method 2
Each of the at least one optical layer includes a first inorganic film having a first refractive index, and a second inorganic film disposed on the first inorganic film and having a second refractive index. A value of the second refractive index may be different from a value of the first refractive index.
Data Source
AI summary
The display device comprises a first electrode and a second electrode disposed on a first surface of a substrate, the first electrode and the second electrode spaced apart from each other, least one light-emitting element disposed between the first electrode and the second electrode, a functional layer disposed on a second surface of the substrate, and a reflective layer disposed between the functional layer and the second surface of the substrate, the reflective layer overlapping the light-emitting element in a plan view.