Optical Resonator Structure for OLED Color Shift Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic electroluminescence (EL) apparatuses suffer from wide light spectrum peaks and low luminance, leading to insufficient color reproducibility and significant color shifts when viewed from different angles due to wavelength shifts and luminance changes, which are not effectively addressed by existing optical resonator structures.
Innovation Solution
Incorporating light-emitting elements with different resonance wavelengths and adjusting the optical length between the light-reflecting layer and the cathode to maintain optimal resonance for red, green, and blue light, with the red light's optical length being longer than the optimal condition to compensate for shifts in other colors, thereby minimizing color shifts when viewed obliquely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an optical resonator structure is employed to reduce spectrum width and increase luminance, then color reproducibility improves at normal viewing angle, but color shifts occur when viewed obliquely due to wavelength shifts
Solution Approach 1:
The patent changes the optical length parameter of the light-emitting element to be longer than the optimal resonance condition. This parameter modification causes the peak wavelength to shift toward the long-wavelength side, which compensates for the blue-shift that occurs during oblique viewing. By adjusting this physical parameter, the invention maintains color stability across different viewing angles while preserving the high luminance benefits of the optical resonator structure.
2Productivity
If the optical length is optimized for normal viewing (0°), then luminance is maximized at front view, but the peak wavelength shifts to lower wavelengths when viewed obliquely
Solution Approach 1:
The patent applies preliminary anti-action by pre-adjusting the optical length to be longer than optimal before viewing occurs. This advance adjustment creates a counteracting effect: the initial long-wavelength shift caused by the extended optical length compensates for the subsequent short-wavelength shift that occurs during oblique viewing. This preemptive measure ensures that the peak wavelength remains stable across different viewing angles, solving the manufacturing precision issue while maintaining high luminance.
3Adaptability or versatility
If multiple light-emitting elements with different resonance wavelengths are used, then color coverage improves, but angle-of-visibility characteristics worsen due to differential wavelength shifts
Solution Approach 1:
The patent applies local quality by giving each light-emitting element (emitting different colors such as red, green, and blue) a specific optical length tailored to its wavelength characteristics. Each element's optical length is locally adjusted to be longer than optimal, with the extension amount potentially varying by element. This localized adjustment ensures that each color component maintains its peak wavelength stability during oblique viewing, thereby maintaining overall color accuracy and reliability across the full color spectrum.
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 ensures stable color reproduction by reducing the shift in peak wavelengths of red, green, and blue light when viewed from various angles, maintaining optimal luminance and color fidelity across different viewing positions.
Implementation Method 1
an optical resonator structure which causes a light emitted from the light-emitting layer to resonate between the light-reflecting layer and the cathode
Data Source
AI summary
A light-emitting apparatus is disclosed, which includes light-emitting elements provided on a substrate that each have a light-emitting layer interposed between a first electrode having a light-transmitting performance and a second electrode having a transflective performance. A light-reflecting layer is further arranged on the light-emitting layer, and an optical resonator structure is configured to resonate a light emitted from the light-emitting layer. A plurality of light-emitting elements are provided, having different resonance wavelengths, and an optical length of the light-emitting elements is set to be longer than λ(m−φ/2π)/2.