Anisotropic Diffusion Film for OLED Viewing Angle Uniformity
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Solution Overview
Problem
Organic light emitting display devices suffer from non-uniform luminance and color deviation due to changes in viewing angle, primarily caused by destructive interference and wavelength shifts, leading to bluish color perception when viewed from the side.
Innovation Solution
An organic light emitting display device incorporating an anisotropic diffusion film with varying diffusion properties based on incident angle, which diffuses light emitted from the organic light emitting diode to improve side luminance and reduce color deviation by dispersing bluish light across a broader area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a micro cavity effect is used to increase light efficiency, then light efficiency is improved, but non-uniform luminance and color deviation occur due to destructive interference and wavelength shifts
Solution Approach 1:
The patent applies a diffusion film with spatially varying diffusion coefficients to different regions of the display. The diffusion coefficient is adjusted locally based on the viewing angle requirements - higher diffusion for off-center pixels and lower diffusion for center pixels - thereby maintaining luminance uniformity across the entire display while preserving the micro cavity effect's light efficiency benefits
Solution Approach 2:
The patent changes the diffusion parameter (diffusion coefficient) of the diffusion film based on the pixel's position and viewing angle. By dynamically adjusting the diffusion parameter across different regions, the system compensates for the wavelength shifts and destructive interference caused by the micro cavity effect, achieving both high light efficiency and uniform luminance
2Use of energy by moving object
If a micro cavity effect is used to increase light efficiency, then light efficiency is improved, but color deviation occurs when viewing angle changes
Solution Approach 1:
The patent implements region-specific diffusion characteristics where each pixel's diffusion property is tailored to its viewing angle. This local quality adjustment ensures that color consistency is maintained across different viewing angles while preserving the light efficiency gains from the micro cavity effect
Solution Approach 2:
The diffusion film acts as an intermediary element between the light emitting layer and the viewer. It mediates the optical path by introducing controlled diffusion that compensates for the wavelength shifts caused by the micro cavity effect, thereby maintaining color consistency without eliminating the light efficiency benefits
3Adaptability or versatility
If viewing angle changes, then optical path length increases, but luminance uniformity deteriorates due to destructive interference
Solution Approach 1:
The patent introduces dynamic diffusion control where the diffusion coefficient varies according to the viewing angle and pixel position. This dynamic adjustment allows the display to maintain luminance uniformity across different viewing angles by adapting the diffusion properties to compensate for changes in optical path length and interference patterns
Solution Approach 2:
Different regions of the display are assigned different diffusion coefficients based on their viewing angle characteristics. This local quality approach ensures that each region maintains optimal luminance uniformity for its specific viewing angle range while preserving overall viewing angle flexibility
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
The anisotropic diffusion film enhances side luminance uniformity and reduces color deviation by diffusing light emitted at specific angles, maintaining consistent color perception across different viewing angles.
Implementation Method 1
an anisotropic diffusion film arranged on the organic light emitting diode, having a diffusion property varied depending on an incident angle
Implementation Method 2
The organic light emitting display device emits light by using an anode, a light emitting layer, and a cathode
Implementation Method 3
as light emitted from the light emitting layer is repeatedly reflected to the anode or the cathode, constructive interference occurs between reflected lights, whereby a micro cavity effect in which light is amplified occurs
Implementation Method 4
side luminance of the organic light emitting display device is deteriorated by destructive interference of partial light emitted from the light emitting layer
Data Source
AI summary
An organic light emitting display device is disclosed, which prevents non-uniform luminance and color deviation caused by a change of a viewing angle from occurring. The organic light emitting display device includes a first substrate having a display area and a non-display area; an organic light emitting diode arranged in the display area of the first substrate; and an anisotropic diffusion film arranged on the organic light emitting diode, having a diffusion property varied depending on an incident angle.