Multi-Color Micro-LED Pixels Using a Shared Active Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current display devices requiring wavelength conversion layers for multi-color emission are complex and costly, particularly in head-mounted displays for virtual and augmented reality, where ultra-small light-emitting diode elements need to emit various colors efficiently.
Innovation Solution
A display device configuration that includes ultra-small light-emitting diode elements emitting red, green, and blue wavelengths without a wavelength conversion layer, utilizing a common electrode layer and varying current densities and application periods for each light-emitting element to achieve color display, with indium content in active layers optimized for efficient light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a wavelength conversion layer is used to enable multi-color emission from ultra-small light-emitting diode elements, then color display capability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies parameter changes by varying the indium content in the active layer of light-emitting diode elements to control emission wavelength. By adjusting the indium composition ratio in InGaN materials, the device can emit different colors (blue, green, yellow, red) without requiring wavelength conversion layers, thus reducing structural complexity while maintaining color display capability
Solution Approach 2:
The patent implements universality by designing a single ultra-small light-emitting diode element structure that can emit multiple wavelengths through composition control. The same basic LED structure with modified indium content can serve multiple color display functions, eliminating the need for separate wavelength conversion layers and enabling one device to perform multiple color emission functions
2Adaptability or versatility
If a wavelength conversion layer is used to enable multi-color emission, then color display capability is improved, but manufacturing cost increases
Solution Approach 1:
The patent reduces manufacturing cost by changing the compositional parameter (indium content) during the growth process rather than requiring additional wavelength conversion layers. This approach simplifies the manufacturing process to a single growth step with variable composition, eliminating the need for separate conversion layer deposition and reducing overall production costs
Solution Approach 2:
The patent extracts and eliminates the wavelength conversion layer from the device structure, relying instead on direct wavelength emission control through material composition. This removal of unnecessary components simplifies the manufacturing process and reduces material and production costs
3Reliability
If different active layers with different indium content are used for different wavelengths, then light emission efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs periodic action by using pulsed molecular beam epitaxy growth with alternating indium supply. During specific growth periods, indium is supplied to achieve desired composition ratios, then supply is paused while other elements are deposited. This periodic indium supply pattern enables precise control of indium content in different LED elements, achieving high emission efficiency while maintaining a relatively simple single-step growth process
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
Enables efficient multi-color display without the need for wavelength conversion layers, simplifying manufacturing and reducing costs by using the same material for multiple light-emitting elements and adjusting current densities and application periods for each color emission.
Implementation Method 1
a first light-emitting element that is configured to emit first light according to a first driving current and a second light-emitting element that is configured to emit second light according to a second driving current
Data Source
AI summary
A display device includes a substrate, a plurality of pixel electrodes on the substrate and spaced apart from each other, a plurality of light-emitting elements on the plurality of pixel electrodes, respectively, and a common electrode layer on the plurality of light-emitting elements and to which a common voltage is applied. The plurality of light-emitting elements include a first light-emitting element that is configured to emit first light according to a first driving current and a second light-emitting element that is configured to emit second light according to a second driving current. An active layer of the first light-emitting element is the same as an active layer of the second light-emitting element.