MicroLED Quantum Dot Light Output via Wavelength-Selective Beam Splitter
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Display devices using quantum dots face inefficiencies due to isotropic light emission, leading to significant light loss and reduced overall efficiency, especially when integrated with microLED technology.
Innovation Solution
Incorporating a beam splitter with specific optical properties, such as titanium dioxide, tantalum pentoxide, or silicon dioxide layers, to direct blue light from microLEDs through while reflecting red and green light back towards the viewer, thereby increasing the light output and efficiency of the display device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If quantum dots are used as conversion material to produce vibrant colors, then color performance is improved, but light output is reduced because QDs emit light isotropically in all directions
Solution Approach 1:
The patent segments the isotropic light emission into directional components by introducing a beam splitter that separates light into different paths. The beam splitter divides the light from quantum dots into forward-going light (toward the viewer) and backward-going light (toward the microLED), allowing selective manipulation of each direction's light properties.
Solution Approach 2:
The patent introduces a beam splitter as an intermediary component between the quantum dots and the microLEDs. This intermediary device captures backward-emitted light and redirects it through the microLED, effectively converting wasted isotropic emission into useful forward-directed light without altering the quantum dots' inherent emission properties.
2Loss of energy
If a beam splitter is introduced to redirect light, then light output is increased, but device complexity increases due to additional optical components
Solution Approach 1:
The beam splitter serves multiple functions simultaneously: it acts as a wavelength-selective mirror to reflect blue light back to the microLED, a beam director to guide green and red light forward to the viewer, and an optical coupler to integrate the quantum dot emission with the microLED structure. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The patent utilizes changes in optical parameters (wavelength-dependent reflection and transmission) of the beam splitter to achieve different functions with a single component. By designing the beam splitter with specific optical properties that vary with wavelength, it can selectively reflect blue light while transmitting green and red light, eliminating the need for multiple wavelength-specific filters or mirrors.
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 enhances light output by over 80% and improves the overall efficiency of the display device by effectively utilizing the beam splitter to redirect and filter light, optimizing the use of quantum dots in microLED technology.
Implementation Method 1
the beam splitter transmits at least 90% of light having a wavelength between 400 nm and 480 nm
Implementation Method 2
reflects at least 90% of light having a wavelength between 500 nm and 800 nm
Implementation Method 3
QDs have the unique ability to emit light at a single spectral peak with narrow line width
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Illumination devices based on quantum dot technology and methods of making such devices are described. An illumination device includes a substrate having a plurality of microLEDs, a beam splitter, and a film having a plurality of quantum dots. The beam splitter includes a plurality of layers and is disposed between the substrate and the film having the plurality of quantum dots.