MicroLED Pixel Optical Structures for Reflection and Edge-Light Control
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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 and masking layers.
Innovation Solution
The use of an array of inorganic light-emitting diodes with a polarizer layer or without, surrounded by diffusers and opaque masking layers with varying refractive indices to redirect edge-emissions and mitigate reflections, along with optional color filters and microlenses for improved light transmission and contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a polarizer layer is added to the display, then reflections are reduced and contrast is improved, but light transmission efficiency decreases
Solution Approach 1:
The patent captures normally wasted edge-emitted light from LEDs and redirects it through diffusers to become useful display light, converting a harmful loss into a beneficial contribution to display brightness and efficiency
Solution Approach 2:
The patent uses microlenses to change the directional parameters of emitted light, focusing edge-emissions at specific angles to redirect them toward the viewer while maintaining control over light distribution
2Use of energy by moving object
If diffusers are added around light-emitting diodes to redirect edge-emissions, then light transmission efficiency improves, but display resolution may deteriorate due to light spreading
Solution Approach 1:
The patent applies different optical properties to different regions: patterned diffusers with varying fill factors in different zones, and position-dependent microlens parameters, to optimize both light extraction and spatial resolution locally across the display
Solution Approach 2:
The patent divides the diffuser into patterned regions with different fill factors and segments the optical control into multiple microlens layers, allowing independent optimization of light extraction efficiency and spatial resolution in different areas
3Object-affected harmful factors
If opaque masking layers are added to mitigate reflections, then contrast improves, but light transmission to optical sensors decreases
Solution Approach 1:
The patent uses tunable opaque masking layers that can dynamically adjust their optical properties to balance reflection mitigation and ambient light transmission to optical sensors based on environmental conditions
Solution Approach 2:
The patent employs phase-separated opaque masking layers with refractive index gradients that can be tuned to optimize the balance between blocking reflections and allowing ambient light to reach optical sensors
4Manufacturing precision
If multiple opaque masking layers with differing properties are used to mitigate reflections, then contrast and resolution improve, but device complexity increases
Solution Approach 1:
The patent combines multiple masking functions into integrated structures that serve both as electrical interconnects and as optical masking elements, reducing the total number of separate layers while maintaining 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
Enhances display efficiency by redirecting edge-emissions towards the viewer, reducing reflections, and allowing additional ambient light to pass through for optical sensors, thereby improving resolution and contrast while minimizing artifacts.
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 array of inorganic light-emitting diodes may be overlapped by a polarizer layer such as a circular polarizer
Implementation Method 3
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
Implementation Method 4
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
Implementation Method 5
The inorganic light-emitting diodes may have reflective sidewalls to mitigate edge-emissions
Implementation Method 6
The phase separated opaque masking layer may have a refractive index gradient along its depth, with a minimum refractive index at an upper surface
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.