Display Device Non-Uniform Underlayer Thickness Control
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Solution Overview
Problem
In display devices with light-emitting elements, ensuring the appropriate height of spacers in the display region is challenging when metal layers are layered in the frame region, leading to potential deposition defects due to uneven film thickness.
Innovation Solution
The display device incorporates a thin film structure with a thicker underlayer and resin layers in the display region compared to the frame region, achieved through selective thinning of the upper resin layer in the frame region, ensuring appropriate film thickness control and reduced spacer height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If metal layers are layered in the frame region to form dummy patterns, gate drivers, or other structures, then the height of the layered body in the frame region increases, but this causes the spacer height in the display region to be insufficient or difficult to ensure
Solution Approach 1:
The patent applies local quality by making the underlayer thickness non-uniform across different regions. Specifically, the underlayer is formed with a first thickness in the display region and a second thickness in the frame region, where the thickness difference compensates for the additional layer heights in the frame region. This localized thickness variation ensures that the overall layered body height remains consistent between display and frame regions, thereby maintaining proper spacer height in the display region while allowing metal layers to be formed in the frame region for dummy patterns and gate drivers.
2Ease of manufacture
If the underlayer is made uniformly thick across the entire substrate, then the manufacturing process is simplified, but the height of spacers in the display region cannot be properly ensured when additional layers are present in the frame region
Solution Approach 1:
The underlayer is designed with spatially varying thickness to compensate for regional differences in layer structure. The underlayer has a first thickness in the display region and a second thickness in the frame region, creating a height compensation effect that ensures consistent overall device height and proper spacer formation in the display region.
Solution Approach 2:
The underlayer thickness is predetermined and pre-formed with the specific thickness variation pattern before subsequent layer deposition. This preliminary action of creating a non-uniform underlayer establishes the height compensation foundation that ensures proper spacer height in the display region before any additional layers are added to the frame region.
Data Source
AI summary
A display device includes: an underlayer, a first insulating film contacting an upper face of the underlayer, a semiconductor layer, a second insulating film, a first metal layer, a first resin layer, a first electrode, and a second resin layer, in order from a lower layer, wherein at least one of the underlayer, the first resin layer, and the second resin layer is a thin film layer having a maximum film thickness in a display region provided with a light-emitting element being thicker than a maximum film thickness in a frame region surrounding the display region.