Conformal DBR Color Conversion Cavity for High-Density Micro-LED Pixels
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Solution Overview
Problem
Existing micro light-emitting diode (pLED) devices with color conversion face limitations due to metal layers between pixel pillars, restricting the use of high-viscous or high-loading wavelength conversion materials, and the lifetime of the wavelength conversion layer is affected by the deposition process, leading to limited aspect ratio and form factor.
Innovation Solution
An optoelectronic device with a semiconductor light-emitting component and a cavity filled with wavelength conversion material, utilizing multilayer interference reflectors on the bottom, top, and sidewalls to enhance light emission efficiency and isolate wavelengths, allowing for high-viscous material use and improved pixel size, with quantum dots or nanophosphor materials for efficient color conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal layers are deposited in trenches between pixel pillars, then mechanical support and shape definition are provided, but the device is not suitable for high-viscous or high-loading wavelength conversion material and the aspect ratio is limited
Solution Approach 1:
The patent removes the metal layer from the trench between pixel pillars, extracting the harmful element that prevented the use of high-viscous wavelength conversion materials. This allows the wavelength conversion material to be applied in the trench without mechanical support constraints, enabling high-loading and high-viscous materials to be used effectively.
Solution Approach 2:
The trench structure is designed to serve multiple functions: it provides optical isolation between pixels, accommodates high-viscous and high-loading wavelength conversion materials, and eliminates the need for separate metal support layers. The removal of metal layers allows the trench to universally support various types of wavelength conversion materials without restriction.
2Stability of the object's composition
If metal layers are deposited between pixel pillars, then structural stability is provided, but the lifetime of the wavelength conversion layer is limited and affected during deposition
Solution Approach 1:
The patent extracts the metal layer that caused degradation to the wavelength conversion layer during deposition. By removing this harmful element, the wavelength conversion layer is no longer exposed to deposition process damage, thereby extending its operational lifetime while maintaining structural stability through alternative means.
Solution Approach 2:
The patent applies a protective coating to the wavelength conversion layer before the deposition process, providing beforehand cushioning against the harmful effects of metal layer deposition. This protective measure prevents degradation and extends the lifetime of the wavelength conversion layer while allowing structural support to be maintained.
3Ease of operation
If separation metal layer is present between pixel pillars, then mechanical isolation is provided, but the form factor and pixel density are limited
Solution Approach 1:
The patent removes the separation metal layer between pixel pillars, extracting the element that occupied space and limited pixel density. This allows for tighter pixel spacing and higher pixel density while maintaining mechanical isolation through the trench structure and surrounding materials.
Solution Approach 2:
The patent transitions from using horizontal metal separation layers to vertical trench structures for mechanical isolation. This dimensional change allows for more efficient space utilization, enabling higher pixel density while maintaining isolation between pixels through the depth of the trench rather than the width of metal layers.
4Ease of manufacture
If wavelength conversion material is not conformally coated, then fabrication is simpler, but the lifetime is limited and it is affected during metal layer deposition
Solution Approach 1:
The patent removes the metal layer deposition step entirely, eliminating the source of damage to the wavelength conversion layer. This allows the wavelength conversion material to be applied without conformal coating protection while still extending its lifetime, as the harmful deposition process is no longer present.
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
The solution improves the efficiency and form factor of micro-LED devices by encapsulating wavelength conversion materials, extending their lifetime and enabling high pixel density with reduced crosstalk, while allowing for efficient light emission and optical isolation, thus overcoming the limitations of existing technologies.
Implementation Method 1
a first multilayer interference reflector provided at a bottom of the cavity directed to the light-emitting component, wherein the first multilayer interference reflector is configured to be transmitive for the first wavelength and is reflective for the second wavelength
Implementation Method 2
the second multilayer interference reflector is configured to be transmitive for the second wavelength and to be reflective for the first wavelength
Implementation Method 3
a cavity filled with a semiconductor wavelength conversion material disposed in a path of the light emitted by the semiconductor light-emitting component for converting the first wavelength into a second wavelength
Data Source
Figure 1~2B
Figure 3A~3B
Figure 4~5
AI summary
An optoelectronic device (100) comprises a semiconductor light-emitting component (101) capable of emitting light at a first wavelength, a cavity (107) filled with a semiconductor wavelength conversion material (103) disposed in a path of the light emitted by the semiconductor light-emitting component (101) for converting the first wavelength into a second wavelength and a first multilayer interference reflector (105) provided at a bottom of the cavity (107) directed to the light-emitting component (101). The first multilayer interference reflector (105) is configured to be transmitive for the first wavelength and reflective for the second wavelength and a second multilayer interference reflector (106) is provided at a top (106') and sidewalls (106") of the cavity (107). The second multilayer interference reflector (106) is configured to be transmitive for the second wavelength and to be reflective for the first wavelength. An associated method of making the optoelectronic device is also provided.