Emissive Display Light Management via Pixel Isolation
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Solution Overview
Problem
Conventional emissive displays using micro-sized emissive elements, such as micro light emitting diodes (μLEDs), suffer from light leakage through transparent substrates, degrading color quality and contrast due to uncontrolled light emission from emissive element wells.
Innovation Solution
The use of light blocking materials, such as reflective metals and absorptive materials like black polymer resin or graphene oxide, to control the directionality of light emitted by micro light emitting diodes (uLEDs) by forming light blocking material layers on the sidewalls and surfaces of emissive element wells, preventing light from propagating to adjacent pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transparent substrate is used to allow light transmission, 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 separated by light-blocking material. Each well is isolated from adjacent wells by these blocking structures, segmenting the light paths so that light emitted in one well cannot propagate to adjacent wells, thereby eliminating light leakage while preserving the transparent substrate's light transmission capability.
Solution Approach 2:
The patent extracts the light-blocking function from the substrate structure by introducing separate light-blocking material layers and sidewall structures. This allows the substrate to maintain its transparent, light-transmitting property while the extracted light-blocking elements are positioned specifically at well interfaces to prevent inter-pixel light leakage.
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 multiple functions into the light-blocking material: it serves as both the well-forming structure and the light-blocking barrier. The sidewalls that define well boundaries simultaneously function as light-blocking structures, merging the mechanical containment function with the optical isolation function to reduce overall device complexity.
Solution Approach 2:
The light-blocking material performs multiple roles: it defines well boundaries, blocks light propagation between wells, and provides structural support. This multi-functionality reduces the need for separate components, thereby improving color quality and contrast without proportionally increasing device complexity.
3Object-affected harmful factors
If light blocking material is deposited on well sidewalls, then light directionality is controlled, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies light-blocking material selectively only where needed - specifically on the sidewalls and bottom surfaces of wells that interface with adjacent wells. This localized application ensures light directionality control at critical interfaces while avoiding unnecessary material deposition elsewhere, thereby reducing the overall manufacturing precision burden.
Solution Approach 2:
The patent forms the light-blocking material structure before populating the wells with emissive elements. This preliminary action allows for more relaxed precision requirements during the critical step of element placement, as the light-blocking framework is already in place to guide and contain light propagation paths.
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 approach effectively reduces light leakage between pixels, enhancing color quality and contrast by ensuring that light is directed only to the top surface of the display, thereby improving the overall performance of emissive displays.
Implementation Method 1
Reflective materials may include metals already incorporated into the backplane manufacturing, including aluminum, titanium, silver, tin, indium, nickel, gold, or other reflective metals
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.