Polychromic LED Stack for Integrated RGB MicroLED Pixels
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Solution Overview
Problem
Existing LED displays face challenges in achieving a wide color gamut and efficient manufacturing of arrays with multiple colors, particularly for microLEDs, due to difficulties in integral formation and assembly of differently colored LEDs.
Innovation Solution
A polychromic LED stack is developed, comprising multiple sets of LED layers with distinct emission wavelengths, each set electrically isolated and independently operable, integrated on a common substrate, allowing for seamless color mixing without separate red, green, and blue sub-pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate red, green, and blue LEDs are assembled to achieve wide color gamut, then color gamut is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent combines multiple LED layers with different emission wavelengths (red, green, blue) into a single integrated LED device. The stack includes a first LED layer emitting red light, a second LED layer emitting green light, and a third LED layer emitting blue light, all integrated within one device structure sharing common electrodes and packaging, eliminating the need for separate LED assemblies.
Solution Approach 2:
The integrated LED stack serves multiple functions simultaneously - it can emit red, green, and blue light from a single device, and can also produce white light by combining all three wavelengths. The common electrodes and packaging structure provide universal support for multiple emission functions.
2Adaptability or versatility
If separately fabricated LEDs of different colors are assembled, then color variety is improved, but manufacturing efficiency decreases
Solution Approach 1:
The patent combines multiple LED layers with different emission wavelengths (red, green, blue) into a single integrated LED device. The stack includes a first LED layer emitting red light, a second LED layer emitting green light, and a third LED layer emitting blue light, all integrated within one device structure sharing common electrodes and packaging, eliminating the need for separate LED assemblies.
3Area of moving object
If microLEDs with small size are used to achieve high pixel density, then pixel density is improved, but integral formation and assembly difficulty increase
Solution Approach 1:
The patent combines multiple LED layers with different emission wavelengths (red, green, blue) into a single integrated LED device. The stack includes a first LED layer emitting red light, a second LED layer emitting green light, and a third LED layer emitting blue light, all integrated within one device structure sharing common electrodes and packaging, eliminating the need for separate LED assemblies.
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 displays with pixels that can emit any color within a defined gamut, eliminating the need for separate LED assembly and facilitating efficient manufacturing of large arrays with high pixel density and independent color control.
Implementation Method 1
Each of the first, second, and third active layers emits light at a corresponding wavelength that differs from the other wavelengths
Data Source
AI summary
Three sets of LED layers each include p-doped and n-doped layers with an active layer therebetween, a tunnel junction layer against the p-doped layer, and an additional n-doped layer against the tunnel junction layer. The first and second LED layer sets are separated by a first semi-insulating semiconductor layer; the second and third LED layer sets are separated by a second semi-insulating semiconductor layer; the second LED layer set is between the first and second semi-insulating semiconductor layers; the third semiconductor layer set is between the second semi-insulating layer and a dielectric layer. Cathode contacts extend through the dielectric layer to the n-doped layers; anode contacts extend through the dielectric layer to the additional n-doped layers. The three LED layer sets can independently emit light at three different corresponding wavelengths, e.g., red, green, and blue light that can encompass an sRGB color gamut or can yield white light.