Chiplet Light Shields for LED Display Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display devices using thin-film transistors are prone to non-uniformity and performance changes due to light exposure, leading to issues with brightness and display behavior, and current shielding methods are limited in complexity and cost-effectiveness.
Innovation Solution
The implementation of first and second light shields in a chiplet-controlled light-emitting diode display device, where the first light shield is located on the surface and the second light shield is beneath the drive circuitry, effectively shielding the circuitry from illumination and reducing electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thin-film transistors are used to control light-emitting elements, then the display device can be manufactured with lower cost and simpler processes, but the transistors exhibit non-uniform electrical performance and are sensitive to light exposure causing brightness variations
Solution Approach 1:
The patent divides the transistor control function into separate segments: the light-emitting element remains controlled by thin-film transistors for manufacturing simplicity, while a dedicated light shield layer is introduced to protect the transistors from harmful light exposure. This segmentation allows each component to optimize its function without compromising the other.
Solution Approach 2:
A light shield layer is introduced as an intermediary component between the light-emitting elements and the thin-film transistors. This intermediate layer blocks harmful light from reaching the transistors while allowing the manufacturing advantages of thin-film technology to be preserved, thus resolving the contradiction between ease of manufacture and display uniformity.
2Reliability
If light shields are added to protect transistors from light exposure, then display uniformity improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The light shield layer is merged with existing display structure layers, specifically integrating it into the pixel electrode structure or adjacent layers. This merging approach allows the light shielding function to be added without creating entirely separate components, thus improving display uniformity while minimizing the increase in device complexity.
Solution Approach 2:
The light shield layer is designed to serve multiple functions: it protects transistors from light exposure, maintains display uniformity, and can be integrated with existing pixel electrode structures. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving the desired reliability improvement.
3Reliability
If light shields are added to protect transistors from light exposure, then display uniformity improves, but manufacturing cost increases
Solution Approach 1:
The light shield layer is designed with optimized optical parameters (light blocking efficiency) and physical parameters (thickness, material composition) to achieve the minimum necessary protection against light exposure. By optimizing these parameters, the manufacturing cost is minimized while still achieving the required display uniformity improvement.
Solution Approach 2:
The patent employs composite material structures for the light shield layer, combining materials that provide effective light blocking with those that are cost-effective and compatible with existing thin-film manufacturing processes. This use of composite materials allows achieving improved display uniformity without proportionally increasing manufacturing costs.
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 solution enhances the performance and stability of the display by reducing light-induced changes in current and brightness, while also simplifying the circuit layout and reducing manufacturing costs.
Implementation Method 1
A first light shield 30A separate from the drive circuitry 26 located on the surface of each chiplet 20 is disposed over the drive circuitry 26 to shield at least a portion of the drive circuitry 26 from illumination
Implementation Method 2
one or more layers 14 of light-emitting material formed over the transparent electrode 12
Implementation Method 3
Light is emitted from a pixel when current passes through the light-emitting material
Implementation Method 4
Light is emitted from a pixel when current passes through the light-emitting material and passes through the transparent electrode and out of the device
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A light-emitting diode display device includes a transparent substrate (10); a plurality of chiplets(20) located over the substrate between a transparent electrode (12) and the substrate, each chiplet including drive circuitry (26) for driving pixels (5) to emit light and including a storage capacitor for storing charge and wherein light illumination of at least a portion of the drive circuit causes the capacitor to leak charge; a connection pad (24) forming a first light shield (30A) separate from the drive circuitry located on the surface of each chiplet disposed over the drive circuitry and substantially shielding at least a portion of the drive circuitry from illumination, the connection pad electrically connected to the drive circuitry; and a second light shield disposed under the drive circuitry between the drive circuitry and the substrate to shield at least a portion of the drive circuitry from illumination.