Organic EL Device Insulation Layer Optical Path Compensation
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Solution Overview
Problem
In organic electroluminescence (EL) devices, the optical resonator structure causes peak wavelengths of luminescence to shift, leading to color deviation and light mixture issues due to differences in optical distances across the pixel electrode, resulting in undesired color display.
Innovation Solution
The organic EL device incorporates a substrate with a first colored layer, a luminescence element, a reflection layer, and an insulation layer, where the pixel electrode has portions that do not overlap and overlap the insulation layer, allowing for adjusted film thickness and optical characteristics to preferentially transmit and absorb light, preventing light with shifted peak wavelengths from mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical resonator structure is provided in the EL element, then luminescence characteristics are improved with a narrow half width of luminescence spectrum, but the peak wavelength of luminescence shifts to a longer wavelength in the peripheral portion due to different optical distances, causing color deviation and light mixture
Solution Approach 1:
The patent applies local quality by differentiating the optical path lengths in different regions of the pixel electrode. The center portion has a first optical path length while the peripheral portion has a second optical path length that is longer. This allows each region to be optimized for its specific function: the center for accurate color emission and the periphery for compensating optical path differences, thereby resolving the contradiction between narrow spectrum width and wavelength uniformity across the display area.
2Manufacturing precision
If a color filter is provided to transmit light of the originally intended peak wavelength, then color accuracy is improved, but light shifted to the long wavelength side is also transmitted, causing light mixture and color deviation
Solution Approach 1:
The patent converts the harmful effect of long-wavelength shifted light into a beneficial compensation mechanism. By designing the peripheral portion with a longer optical path length, the light emitted from this region is intentionally shifted to longer wavelengths. This shifted light then serves to compensate for the spectral narrowing effect in the center region, broadening the overall luminescence spectrum and preventing color deviation, thus transforming a potential harm into a benefit.
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 reduces color deviation and enhances display quality by ensuring that only the intended peak wavelengths are transmitted, resulting in improved color purity and consistency across the display.
Implementation Method 1
a film thickness of the insulation layer or optical characteristics of the first colored layer are set so that the first light is transmitted through the first colored layer more than the second light is
Implementation Method 2
a first reflection layer which is disposed between the first surface and the first pixel electrode and forms a first resonator structure between the first reflection layer and the opposite electrode
Data Source
AI summary
An organic EL device includes a substrate, a first colored layer, a first luminescence element having a first pixel electrode, a reflection layer, and an insulation layer which overlaps a second portion without overlapping a first portion of a first pixel electrode. Light emitted from the first luminescence element includes a first light emitted from a region overlapping a first portion and a second light emitted from a region overlapping a second portion, and a film thickness of an insulation layer or optical characteristics of the first colored layer are set so that the first light is transmitted through the first colored layer more than the second light is.