Organic EL Display Pad Protection via Substrate Thickness Variation
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Solution Overview
Problem
The reduction in thickness of the lower substrate in organic electro-luminescence display devices to make them thinner and slimmer leads to damage at the pad portion during manufacturing steps like chip on glass or FPC, reducing yield and causing breakage.
Innovation Solution
A method where the lower substrate has a thicker first region overlapping the pad portion and a thinner second region, with an etching preventive portion formed using acid-resistant paste to prevent etching in the pad area, and a polarization plate attached to the thinner region to enhance rigidity and prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the lower substrate is reduced to make the display device thinner and slimmer, then the volume and weight of the device are reduced, but the lower substrate becomes prone to breaking during chip on glass step, FPC step, or modulizing step
Solution Approach 1:
The lower substrate is designed with non-uniform thickness: a first thickness in the first region (pad portion area) and a second thickness in the second region (display area), where the first thickness is greater than the second thickness. This local quality variation allows the substrate to be thin overall while maintaining strength at critical areas.
Solution Approach 2:
The lower substrate is segmented into two distinct regions with different thicknesses: a first region overlapping the pad portion and a second region overlapping the display area. This segmentation enables differential thickness control to balance structural strength and device slimness.
2Length of moving object
If the thickness of the lower substrate is reduced uniformly, then the display device becomes thinner, but the pad portion becomes vulnerable to damage during assembly processes
Solution Approach 1:
The substrate thickness is locally optimized: the first region under the pad portion has greater thickness for reliability, while the second region has lesser thickness for slimness. This local quality differentiation resolves the contradiction between overall thinness and localized strength.
Solution Approach 2:
Instead of uniform thickness reduction in one dimension, the solution introduces thickness variation across different spatial regions of the substrate, using dimensional differentiation to simultaneously achieve thinness and reliability.
Data Source
AI summary
The present invention relates to an organic electro-luminescence display device and a method for fabricating the same, in which damage to a pad portion is prevented for improving yield.The organic electro-luminescence display device includes a thin film transistor array unit formed on a front surface of a lower substrate and a pad portion extended from the thin film transistor array unit, an organic EL array unit on the thin film transistor array unit having a matrix of organic EL cells, and a protective member for protecting the organic EL array unit and the thin film transistor array unit and exposing the pad portion to an outside, wherein the lower substrate has a thickness of a first region overlapped with the pad portion thicker than a thickness of a second region overlapped with the thin film transistor array unit.