OLED Cathode Thickness Variation for Spacer Lap Joint
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Solution Overview
Problem
The uneven surface of OLED array substrates due to spacers leads to poor lap joints and increased cathode resistance, resulting in higher power consumption and reduced light transmittance, which adversely affects the display effect.
Innovation Solution
The cathodes are designed with a thicker first region covering the spacers and a thinner second region, with the thickness difference ranging from 1 to 20 nanometers, to enhance the lap joint without compromising light transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the cathode is made thin to achieve high light transmittance, then light transmittance is improved, but the lap joint at uneven portions becomes poor and cathode resistance increases
Solution Approach 1:
The cathode is designed with different thicknesses in different regions: a first thickness in the first region (covering spacer projections) and a second thickness in the second region (pixel electrode region). This local differentiation allows the cathode to have sufficient thickness at spacer locations for good lap joint and low resistance, while maintaining thin thickness at pixel regions for high light transmittance.
2Reliability
If the cathode is thickened to improve lap joint at uneven surfaces, then reliability is improved, but light transmittance decreases
Solution Approach 1:
The cathode structure implements spatially varying thickness: thicker at spacer locations (first region) to ensure reliable lap joint and lower resistance, and thinner at pixel electrode regions (second region) to maintain high light transmittance. This resolves the contradiction by applying different thickness characteristics to different functional regions.
3Use of energy by moving object
If the cathode thickness is increased to reduce cathode resistance, then power consumption is reduced, but light transmittance and display effect are adversely influenced
Solution Approach 1:
The cathode thickness is optimized locally: increased thickness in the first region over spacers reduces contact resistance and improves electrical connection, thereby reducing power consumption. Meanwhile, the thinner second region in pixel areas preserves high light transmittance for good display effect. This local differentiation simultaneously addresses both electrical and optical performance requirements.
Data Source
AI summary
An OLED array substrate and a method for manufacturing the same, an OLED packaging structure and a display device are provided by the present disclosure. The OLED array substrate includes thin film transistors, anodes, cathodes and organic light-emitting layers arranged between the anodes and the cathodes. The OLED array substrate further includes spacers configured to support the OLED array substrate and a packaging substrate so as to form a cell gap therebetween. Each cathode includes a first region which covers the corresponding first spacer and a second region beyond the first regions, and a thickness of the cathode at the first region is larger than a thickness of the cathode at the second region.