Reflective Bank Sidewall for OLED Subpixel Light Management
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Solution Overview
Problem
Organic light emitting display devices, particularly in head-mounted displays, suffer from color mixture and light loss due to light emission at certain angles, which affects image quality and efficiency.
Innovation Solution
A display device design featuring a substrate with subpixel areas, electrodes, an organic light emitting layer, and a reflective portion on the bank between subpixels, which reflects light emitted from one subpixel area back to prevent it from entering adjacent areas, thereby reducing color mixture and light loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light is emitted from organic light emitting layer at certain angles, then viewing angle and contrast ratio are improved, but color mixture and light loss occur in adjacent pixels
Solution Approach 1:
A reflective bank structure is introduced as an intermediary element between adjacent subpixels. The bank includes a reflective portion that intercepts obliquely emitted light and redirects it back to the original subpixel, preventing the light from entering adjacent subpixels. This mediator structure resolves the contradiction by maintaining wide viewing angles while eliminating color mixture and light loss.
Solution Approach 2:
The reflective bank converts the harmful obliquely emitted light that would cause color mixture into a beneficial element by reflecting it back to the original subpixel. The light that would otherwise be wasted or cause interference is now utilized to enhance the brightness and purity of the intended subpixel, transforming the harmful effect into a benefit.
2Device complexity
If no reflective portion is provided on the bank, then device complexity is reduced, but light efficiency deteriorates due to light loss
Solution Approach 1:
The reflective bank serves as a simple intermediary structure that redirects light without requiring complex active components. By using a passive reflective surface integrated into the bank structure, the patent achieves light efficiency improvement while maintaining relatively simple device architecture, balancing complexity and performance.
Solution Approach 2:
The reflective bank structure performs dual functions: it provides mechanical separation between subpixels and simultaneously redirects obliquely emitted light back to the source subpixel. This self-service approach eliminates the need for additional light management components, improving light efficiency without significantly increasing device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances light efficiency by preventing color mixture and light loss, improving image quality and reducing power consumption in head-mounted displays.
Implementation Method 1
the reflective portion may reflect light, which is emitted from the first subpixel area, toward the first subpixel area to prevent the light from entering the second subpixel area adjacent to the first subpixel area through the bank
Data Source
AI summary
A display device includes a substrate provided with a first subpixel area, and a second subpixel area adjacent to one side of the first subpixel area, a first electrode provided on the substrate, including a first sub electrode provided on the first subpixel area and a second sub electrode provided on the second subpixel area, an organic light emitting layer arranged on the first electrode, a second electrode arranged on the organic light emitting layer, a bank provided between the first sub electrode and the second sub electrode, partitioning the first subpixel area from the second subpixel area, and a reflective portion provided on the bank, adjoining the organic light emitting layer.