Emissive Display Light Management via Segmented Wells
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Solution Overview
Problem
Conventional micro-sized emissive displays suffer from light leakage through transparent substrates, degrading color quality and contrast due to uncontrolled light emission from emissive elements.
Innovation Solution
A light management system is implemented using light blocking materials such as metals and absorptive materials to control the directionality of light emitted by micro light emitting diodes (uLEDs), ensuring that light is directed only to the top surface and not propagated to adjacent pixels, thereby reducing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transparent substrate is used to form the display, then light can propagate through the substrate, but light leaks between adjacent wells degrading color quality and contrast
Solution Approach 1:
The patent divides the substrate into discrete wells that are separated by light-blocking material. Each well is individually isolated to contain light from emissive elements within that specific well, preventing light from propagating to adjacent wells. This segmentation approach maintains the transparency benefit for light extraction while eliminating the harmful light leakage between pixels.
Solution Approach 2:
The patent introduces light-blocking material as an intermediary substance between adjacent wells. This material acts as a barrier that selectively blocks light propagation paths between wells while allowing light to pass through the substrate above the wells. The intermediary material resolves the contradiction by enabling light transmission where needed while blocking it where harmful.
2Object-affected harmful factors
If light blocking material is added to prevent light leakage, then color quality and contrast improve, but device complexity increases
Solution Approach 1:
The patent combines the light-blocking function with the existing well structure by forming light-blocking material as sidewalls of the wells during the same fabrication process. Rather than adding separate light-blocking components, the blocking material is integrated into the well formation process, merging two functions (containment and light blocking) into a single structural element.
Solution Approach 2:
The light-blocking material serves multiple functions simultaneously: it defines the well boundaries for capturing emissive elements, prevents light leakage between adjacent wells, and provides structural support. This multi-functionality reduces the need for additional components and simplifies the overall device architecture while achieving light leakage prevention.
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 light management system effectively enhances color quality and contrast by preventing light leakage between pixels, ensuring that light is emitted in controlled directions perpendicular and parallel to the display surface.
Implementation Method 1
The structure features described herein are used to reflect or absorb this light
Implementation Method 2
Absorptive materials may include black polymer resin and black photoresist materials containing carbon black or graphene oxide
Data Source
AI summary
A method is provided for fabricating an emissive display substrate with a light management system. The method provides a transparent first substrate with a top surface and forms a plurality of emissive element wells. The well sidewalls are formed from a light absorbing material or a light reflector material. In one aspect, a light blocking material film layer is formed overlying the first substrate top surface, and the emissive element sidewalls are formed in the light blocking material film layer. In another aspect, a transparent second substrate is formed overlying the first substrate top surface. Then, the emissive element wells are formed in the second substrate with via surfaces, and the light blocking material is deposited overlying the well via surfaces. Additionally, the light blocking material may be formed on the bottom surface of each well. An emissive display substrate with light management system is provided below.