Multicolor OLED Resonator Structure for Viewing Angle Color Shift
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Solution Overview
Problem
Existing display apparatuses suffer from color shift issues when viewed from different angles due to optical interference, leading to reduced light extraction efficiency and increased power consumption, particularly when using optical filters like color filters which complicate the constitution and increase production costs.
Innovation Solution
A multicolor display apparatus with a resonator structure where the optical path between reflective surfaces is adjusted to resonate light, with the peak wavelength of the multiple interference spectrum offset for the color with highest visual sensitivity and coinciding for other colors, eliminating the need for optical filters and optimizing light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a color filter is added to diffuse emitted light and reduce viewing angle dependence, then color shift is suppressed, but device complexity increases and light extraction efficiency decreases
Solution Approach 1:
The invention extracts and eliminates the color filter component from the display device structure. By adjusting the resonator structure parameters (optical path length, reflective surface properties) to offset the emission spectrum peak, the patent achieves color stability without requiring external color filters, thus reducing device complexity while maintaining color accuracy across viewing angles
Solution Approach 2:
The invention introduces an optical intermediary mechanism - the resonator structure with adjusted optical path - that mediates between the light-emitting layer and the external environment. By controlling the resonant conditions and optical interference within this intermediary structure, the patent suppresses viewing angle dependence and color shift without needing color filters, thereby resolving the contradiction between color stability and device simplicity
2Stability of the object's composition
If a color filter is added to suppress color shift, then color stability improves, but light extraction efficiency decreases
Solution Approach 1:
The invention removes the color filter component that causes light absorption and energy loss. Instead, it uses resonator structure parameter adjustment to achieve color stability, allowing maximum light extraction efficiency while suppressing viewing angle dependence and color shift
Solution Approach 2:
The resonator structure serves as an optical intermediary that controls light extraction without absorbing significant energy. By adjusting its optical path length and reflective properties, it achieves color stability while maintaining high light extraction efficiency, unlike color filters that absorb light and reduce efficiency
3Stability of the object's composition
If the peak wavelength of emission spectrum and multiple interference spectrum are offset, then viewing angle dependence is suppressed, but emission efficiency decreases
Solution Approach 1:
The invention changes the parameters of the resonator structure (optical path length, refractive index, reflective surface properties) to create a controlled offset between emission spectrum peak and multiple interference spectrum peak. This parameter adjustment suppresses viewing angle dependence while minimizing the impact on emission efficiency by optimizing the offset amount rather than using large offsets that would significantly reduce efficiency
4Use of energy by moving object
If the peak wavelengths are made to coincide, then emission efficiency increases, but viewing angle dependence increases
Solution Approach 1:
The invention optimizes the resonator structure parameters to achieve a small, controlled offset between peak wavelengths. This balances emission efficiency and color stability by finding the optimal offset amount that maintains high efficiency while suppressing viewing angle dependence, rather than complete coincidence or large offset
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 approach reduces color shift and power consumption while maintaining high viewing angle display quality by adjusting the resonator structure to control light-emitting characteristics, achieving efficient light extraction and stable white color reproduction.
Implementation Method 1
an optical path between a reflective surface which is closer to the cathode than the light-emitting layer is and a reflective surface which is closer to the anode than the light-emitting layer is, is set to serve as a resonating portion of a resonator structure for resonating light emitted by the light-emitting layer
Implementation Method 2
emitted light is reflected due to various refractive index differences, so that optical interference occurs
Data Source
AI summary
Provided is a multicolor display apparatus including a plurality of organic light-emitting devices each including a pair of electrodes of an anode and a cathode; and an organic compound layer interposed between the pair of electrodes and including a light-emitting layer. The viewing angle characteristics of the organic light-emitting device showing an emission color with a highest visual sensitivity is such that a peak wavelength of emission spectrum and a peak wavelength of multiple interference spectrum due to the organic light-emitting device are offset with respect to each other so that the color shift of a display image on the multicolor display apparatus depending on a viewing angle is suppressed.