Pixel Optical Structures for Redirecting LED Edge Emissions
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Solution Overview
Problem
Electronic devices with displays often face issues of lower than desired resolution, contrast, and efficiency due to inadequate light management, leading to artifacts such as reflections and misalignment of LEDs, which affect the overall display quality.
Innovation Solution
The implementation of an inorganic light-emitting diode display with a polarizer layer, diffuser, opaque masking layers, and optional color filters and microlenses to redirect edge-emissions, mitigate reflections, and enhance ambient light transmission, while using phase-separated opaque masking layers with refractive index gradients to optimize light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a polarizer layer is added to the display, then display efficiency and light transmission are improved, but device complexity increases
Solution Approach 1:
The display structure is segmented into multiple functional layers including inorganic light-emitting diodes, diffusers, color filter layers, and polarizer layers. Each layer performs a specific function to optimize light emission and transmission while managing complexity through modular design.
Solution Approach 2:
Diffusers are introduced as intermediary elements between the light-emitting diodes and the viewer. These diffusers redirect edge-emissions and manage light distribution, acting as mediators that improve display efficiency without requiring direct modification of the LED structure.
2Use of energy by moving object
If diffusers are used to redirect edge-emissions, then light transmission and display efficiency are improved, but manufacturing precision requirements increase
Solution Approach 1:
The diffusers are strategically positioned and configured with specific optical properties to redirect light in particular directions. The diffuser layers have localized functions to manage edge-emissions from specific LED regions, optimizing light transmission without requiring uniform precision across the entire display structure.
3Illumination intensity
If opaque masking layers are added to mitigate reflections, then display contrast is improved, but device complexity increases
Solution Approach 1:
Opaque masking layers are introduced to convert the harmful effect of reflections into a beneficial outcome. By strategically placing these layers, reflections that would otherwise degrade display contrast are blocked, and the same structures serve to define pixel boundaries and improve overall contrast.
4Reliability
If the display is designed to allow ambient light transmission for optical sensors, then sensor functionality is improved, but display efficiency may be compromised
Solution Approach 1:
The display structure incorporates localized transparent regions or openings at specific locations where optical sensors are positioned. These local modifications allow ambient light transmission to the sensors without significantly compromising the overall light emission efficiency of the display, as the majority of the display area maintains its optimized light transmission properties.
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 configuration improves display efficiency by redirecting edge-emissions towards the viewer, reducing reflections, and allowing additional ambient light to reach optical sensors, thereby enhancing the display's resolution, contrast, and overall visual quality.
Implementation Method 1
Each inorganic light-emitting diode may be surrounded by a diffuser that redirects edge-emissions towards a viewer
Implementation Method 2
The inorganic light-emitting diodes may have reflective sidewalls to mitigate edge-emissions
Implementation Method 3
The phase separated opaque masking layer may have a refractive index gradient along its depth, with a minimum refractive index at an upper surface
Implementation Method 4
The array of inorganic light-emitting diodes may be overlapped by a polarizer layer such as a circular polarizer
Data Source
AI summary
An electronic device may have a display with an array of inorganic light-emitting diodes. The array of inorganic light-emitting diodes may be overlapped by a polarizer layer such as a circular polarizer. Alternatively, the display may be a polarizer-free display without any polarizer layer over the array of inorganic light-emitting diodes. Each inorganic light-emitting diode may be surrounded by a diffuser that redirects edge-emissions towards a viewer. A top diffuser, a color filter layer, a microlens, and/or a microlens with color filtering and/or diffusive properties may also optionally overlap each inorganic light-emitting diode. The inorganic light-emitting diodes may have reflective sidewalls to mitigate edge-emissions. In this type of arrangement, the array of inorganic light-emitting diodes may be coplanar with one or more opaque masking layers. To mitigate reflections, the display may include two opaque masking layers having differing properties or a single phase separated opaque masking layer.