Display Electrode Layout With Sloped Contact Hole Against Short Circuits
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Solution Overview
Problem
Display devices using inorganic light-emitting elements face issues with short circuits and cracks in the second electrode, leading to defective pixels and increased production time due to the need for a descum process.
Innovation Solution
The display device incorporates optical layers with varying thicknesses and shapes, including a gently sloped contact hole in the second optical layer, which prevents short circuits and cracks, allowing the omission of the descum process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical layer thickness is increased to prevent short circuits and cracks in the second electrode, then electrode reliability is improved, but manufacturing complexity increases due to the need for precise thickness control in different regions
Solution Approach 1:
The patent applies local quality by varying the thickness of the optical layer in different regions: the first optical layer has a first thickness in a first region and a second thickness in a second region, with the first thickness being greater than the second thickness. This localized thickness variation prevents short circuits and cracks in the second electrode where needed while maintaining manufacturing feasibility.
2Reliability
If the contact hole slope is made gentle to prevent short circuits, then electrode stability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the geometric parameter of the contact hole from a steep slope to a gentle slope. This parameter modification prevents short circuits in the second electrode while the gradual transition helps mitigate the precision requirements through more tolerant fabrication processes.
3Productivity
If the descum process is omitted to reduce production time and energy consumption, then productivity is improved, but visual defects such as mura may increase
Solution Approach 1:
The patent performs preliminary action by optimizing the optical layer thickness and contact hole geometry before the descum process would normally be applied. The first optical layer with greater thickness in the first region and the gently sloped contact hole prevent residue formation and short circuits in advance, making the descum process unnecessary while maintaining display quality.
4Reliability
If multiple optical layers with different thicknesses are used to prevent short circuits, then electrode integrity is improved, but manufacturing time increases due to additional layer formation steps
Solution Approach 1:
The patent merges the functions of multiple optical layers into a single optical layer with spatially varying thickness. Instead of forming separate first and second optical layers with different thicknesses, a single optical layer is created with a first thickness in a first region and a second thickness in a second region, reducing the number of fabrication steps while maintaining electrode integrity.
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 configuration enhances electrode stability, reduces visual defects, and simplifies manufacturing by preventing short circuits and cracks, while improving brightness uniformity and reducing production time and energy consumption.
Implementation Method 1
a third optical layer containing light-diffusing particles improves brightness uniformity and reduces visual defects such as mura
Data Source
AI summary
A display device according to the present disclosure may include a substrate including a plurality of pixels, a plurality of pixel driving circuits disposed on the substrate, and a plurality of light-emitting elements disposed on each of the plurality of pixel driving circuits. A first optical layer may surround the plurality of light-emitting elements, while a second optical layer is disposed outside the first optical layer. An electrode may be disposed to extend across the first optical layer, the second optical layer, and a contact hole within the second optical layer. The first optical layer and the second optical layer may have different thicknesses from each other. This difference in thickness can prevent short circuits in the electrode by forming a gentler slope at the contact hole, improving device reliability and allowing the manufacturing process to omit a descum step, thereby enhancing production efficiency.