OLED Display Filling Material Segmentation for Strength and Light Loss
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Solution Overview
Problem
Existing organic light-emitting display apparatuses face challenges in enhancing structural strength and minimizing light loss, particularly due to the presence of filling materials that can attenuate light emission.
Innovation Solution
The use of a patterned filling material between the display substrate and the encapsulation substrate, with the filling material only in non-light-emission areas, along with a conductive layer to improve electrical contact and a color filter and black matrix to enhance light extraction and contrast, addresses the issues of structural integrity and light loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If filling material is used between display substrate and encapsulation substrate, then structural strength is improved, but light loss occurs due to light attenuation by the filling material
Solution Approach 1:
The filling material is segmented into two distinct regions: a first filling material positioned in the non-light-emission area and a second filling material positioned in the light-emission area. This segmentation allows each region to serve its specific function - the first region provides structural support while the second region maintains light transmission properties, thereby resolving the contradiction between structural strength and light loss.
Solution Approach 2:
Different filling materials with different properties are used in different locations. The first filling material in the non-light-emission area is optimized for structural strength, while the second filling material in the light-emission area is optimized for light transmission. This local differentiation of material properties resolves the contradiction by allowing each area to have the quality needed for its specific function.
2Illumination intensity
If filling material is placed in non-light-emission area only, then light extraction efficiency is improved, but structural strength in the overall apparatus may be compromised
Solution Approach 1:
The filling material is divided into spatially separated first and second filling materials. The first filling material in the non-light-emission area provides structural support without interfering with light extraction, while the second filling material in the light-emission area maintains light transmission. This segmentation resolves the contradiction by distributing different functional requirements to different spatial locations.
Solution Approach 2:
The dual filling material configuration serves multiple functions simultaneously: the first filling material provides structural support and isolation, while the second filling material maintains light transmission and electrical contact. This multi-functionality resolves the contradiction by having different regions perform different functions that collectively satisfy both light extraction efficiency and structural strength requirements.
3Reliability
If conductive layer is added between filling material and OLEDs, then electrical contact is improved, but device complexity increases
Solution Approach 1:
A conductive layer is introduced as an intermediary element between the filling material and the OLEDs. This conductive layer serves as a mediator that ensures reliable electrical contact between the cathode electrode and the filling material, thereby resolving the contradiction between improved electrical contact and increased device complexity by providing a dedicated intermediate component for electrical connection.
Data Source
AI summary
An organic light-emitting display apparatus includes: a display substrate; a plurality of organic light-emitting diodes (OLEDs) on the display substrate, the OLEDs being divided from one another by a pixel defining layer (PDL); an encapsulation substrate on the display substrate and covering the OLEDs; a filling material on the PDL and between the display substrate and the encapsulation substrate; and a cavity between the OLEDs and the encapsulation substrate.