Micro Lens Focusing Layer Layout to Reduce Display Warpage
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Solution Overview
Problem
The accumulation of residual tensile stresses in the thick copper layers and focusing layers of display devices due to manufacturing processes leads to device warpage, which impedes subsequent manufacturing processes, particularly when warpage exceeds 0.8 mm.
Innovation Solution
The display device incorporates a focusing layer with a series of organic layers formed as discontinuous film structures and includes insulating layers with compressive stresses to offset residual tensile stresses, reducing warpage while maintaining optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thick copper layers and focusing layers are used in the backplane, then light extraction efficiency is improved, but residual tensile stresses accumulate causing device warpage
Solution Approach 1:
The focusing layer is divided into multiple discrete focusing structures rather than a continuous thick layer. Each focusing structure is positioned over specific light-emitting elements, segmenting the stress distribution and preventing cumulative tensile stress that causes warpage while maintaining light extraction efficiency.
Solution Approach 2:
The patent modifies the thickness and material composition parameters of the focusing layer to reduce residual tensile stress. By optimizing these parameters, the layer maintains sufficient optical functionality for light extraction while minimizing stress accumulation that leads to device warpage.
2Ease of manufacture
If continuous film structure is used for focusing layer, then manufacturing simplicity is improved, but residual tensile stresses increase leading to warpage
Solution Approach 1:
The focusing layer is segmented into multiple discrete structures rather than a continuous film. This segmentation reduces the cumulative tensile stress while the standardized fabrication process maintains manufacturing simplicity through conventional photolithography and deposition techniques.
Solution Approach 2:
An organic layer is introduced as an intermediary between the substrate and the focusing structures. This intermediate layer helps manage stress distribution and facilitates the transition from continuous film to segmented structure fabrication.
Data Source
AI summary
A display device includes an array substrate, a first organic layer, a second organic layer, a third organic layer, and a plurality of micro lenses. The array substrate has a plurality of light-emitting elements disposed thereon. The first organic layer is on the array substrate and covers the light-emitting elements. The second organic layer is on the first organic layer. The third organic layer is on the second organic layer. The third organic layer has a portion extending downward through the second organic layer. The micro lenses are over the third organic layer and disposed corresponding to the light-emitting elements, respectively.