OLED Microcavity Color Shift Compensation via Auxiliary Layer
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Solution Overview
Problem
Organic light emitting diode (OLED) displays experience a decrease in brightness and color shift as the viewing angle increases, leading to a deterioration in display quality due to changes in brightness and color coordinates.
Innovation Solution
Incorporating an auxiliary light emitting layer between the first and second electrodes, and optimizing the thickness of the organic light emitting diode to ensure the main peak wavelength of light out-coupling between the electrodes is larger than the main peak wavelength of light emitted from the organic light emitting layer, with a difference within a specific range (-14nm to -2nm), to minimize color coordinate variations across a range of viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a microcavity effect is used to improve luminous efficiency and color purity, then luminous efficiency and color purity are improved, but brightness decreases and color shift occurs as viewing angle increases
Solution Approach 1:
The patent changes the optical parameters of the device by introducing an auxiliary light emitting layer with specific optical properties. This layer has a main peak wavelength that is blue-shifted relative to the organic light emitting layer, and its optical intensity and wavelength are carefully controlled to compensate for the microcavity effect's viewing angle dependence, thereby maintaining consistent color and brightness across different viewing angles
Solution Approach 2:
The patent combines the organic light emitting layer with an auxiliary light emitting layer to create a composite light emitting structure. This composite structure integrates two different light emitting materials with complementary optical characteristics, where the auxiliary layer compensates for the color shift and brightness reduction caused by the microcavity effect in the organic light emitting layer
2Manufacturing precision
If a microcavity effect is used to improve color purity, then color purity is improved, but color coordinates shift as viewing angle increases
Solution Approach 1:
The patent introduces an auxiliary light emitting layer with a main peak wavelength that is blue-shifted relative to the organic light emitting layer. By carefully controlling the optical intensity and wavelength of this auxiliary layer, the patent compensates for the color coordinate shifts caused by the microcavity effect, thereby maintaining stable color coordinates across different viewing angles while preserving the color purity benefits
Solution Approach 2:
The auxiliary light emitting layer acts as an intermediary element that mediates between the organic light emitting layer and the viewer. It introduces compensatory light with specific wavelength characteristics that counteract the color shift effects, serving as a buffer that maintains color coordinate stability without eliminating the microcavity effect's color purity enhancement
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 configuration effectively minimizes brightness changes and color shifts, maintaining display quality by controlling the color coordinate variation rate within acceptable limits, preventing noticeable color shifts and ensuring consistent image appearance across various viewing angles.
Implementation Method 1
an organic light emitting layer 55 between the first electrode 47 and the second electrode 58
Implementation Method 2
a microcavity effect is used to improve luminous efficiency and color purity of a displayed image. The microcavity effect is a phenomenon that light emitted from the organic light emitting layer 55 is repeatedly selectively reflected between specific layers
Data Source
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AI summary
An organic light emitting diode (E) includes a first electrode (147) and a second electrode (158); an organic light emitting layer (155) between the first electrode (147) and the second electrode (158); and a auxiliary light emitting layer (152) between the first electrode (147) and the organic light emitting layer (155) or between the organic light emitting layer (155) and the second electrode(158), wherein a difference between a main peak wavelength of light emitted from the organic light emitting layer (155) itself and a main peak wavelength of light out-coupling between the first and second electrodes (147, 158) is within a range of -14nm to -2nm.