OLED Display Stress Adjustment Layer for Bending
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Solution Overview
Problem
The challenge in organic light emitting diode (OLED) displays is the increased stress and asymmetry of strains when bent, leading to picture abnormalities due to the displacement of the neutral plane caused by external and internal films, making it difficult to position the OLED elements correctly.
Innovation Solution
The introduction of a stress adjustment layer with specific patterns, such as triangular, trapezoidal, or semicircular shapes, beneath the passivation film to reduce bending stress and maintain the neutral plane alignment, minimizing stress in bent portions and preventing asymmetry of strains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the organic light emitting diode display is increased by internal and external films, then the display provides better protection and functionality, but the tensile stress and compressive stress are increased and the neutral plane becomes displaced
Solution Approach 1:
The patent applies local quality by positioning the organic light emitting element specifically in the neutral plane region of the bent display, where stress is minimized. This localized placement ensures that the sensitive emitting element experiences reduced mechanical stress while other regions of the display can have the necessary protective films and structures.
Solution Approach 2:
The patent uses the concept of counterweight by creating a balanced stress distribution through the layered structure design. The multiple films and layers are arranged to create opposing stresses that balance each other, with the neutral plane positioned at a specific depth where tensile and compressive stresses are equal and minimized, allowing the OLED element to be placed in this balanced region.
2Reliability
If the thickness of the organic light emitting diode display is increased by internal and external films, then the display provides better protection and functionality, but the neutral plane becomes displaced making it difficult to position the organic light emitting element correctly
Solution Approach 1:
The patent applies local quality by positioning the organic light emitting element specifically in the neutral plane region of the bent display, where stress is minimized. This localized placement ensures that the sensitive emitting element experiences reduced mechanical stress while other regions of the display can have the necessary protective films and structures.
Solution Approach 2:
The patent employs preliminary action by pre-calculating and pre-positioning the organic light emitting element at the correct depth within the layered structure during manufacturing. The neutral plane position is determined in advance based on the specific film stack configuration, and the OLED element is placed at this predetermined location before the display is bent, ensuring optimal stress distribution from the outset.
3Ease of operation
If the display is bent to achieve flexibility and thinness, then the display can be easily bent and reduced in thickness, but stress occurs with tensile stress toward the convex outer surface and compressive stress toward the concave inner surface
Solution Approach 1:
The patent applies local quality by positioning the organic light emitting element specifically in the neutral plane region of the bent display, where stress is minimized. This localized placement ensures that the sensitive emitting element experiences reduced mechanical stress while other regions of the display can have the necessary protective films and structures.
Solution Approach 2:
The patent utilizes flexible shells and thin films by employing a layered structure of multiple thin film layers that can accommodate bending. The thin film encapsulation layers and protective films are designed with appropriate thicknesses and material properties to provide flexibility while maintaining protection, allowing the display to be bent without excessive stress accumulation.
4Reliability
If the display has a layered structure made of complex materials, then the display provides comprehensive protection and functionality, but asymmetry of strains occurs due to a difference in tensile stress and compressive stress at the inner and outer surfaces
Solution Approach 1:
The patent uses the concept of counterweight by creating a balanced stress distribution through the layered structure design. The multiple films and layers are arranged to create opposing stresses that balance each other, with the neutral plane positioned at a specific depth where tensile and compressive stresses are equal and minimized, allowing the OLED element to be placed in this balanced region.
Solution Approach 2:
The patent applies parameter changes by adjusting the thicknesses, material properties, and arrangement of the various layers in the layered structure to optimize the stress distribution. By modifying these parameters, the design achieves a more symmetric strain distribution while maintaining comprehensive protection and functionality.
Data Source
AI summary
Disclosed is an organic light emitting diode display including an organic light emitting display panel configured to display an image, and a lower passivation film attached to a bottom of the organic light emitting diode display panel. The lower passivation film includes a support film that is in contact with the organic light emitting diode display panel, and a stress adjustment layer formed beneath the support film and configured to reduce a bending stress to be induced in the organic light emitting display panel when the organic light emitting display panel and the lower passivation film are bent.