Photochromic Layer for OLED Displays Without Polarizing Plates
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Solution Overview
Problem
OLED display devices with polarizing plates face issues of increased cost and reduced brightness due to external light reflection and color mix problems, especially when viewed from different angles.
Innovation Solution
A light emitting display panel structure that includes a substrate, electrodes, a light emitting layer, an encapsulation layer, and a photochromic layer without a polarizing plate, where the photochromic layer changes transparency based on wavelength, enhancing field-of-view, reducing external light reflectance, and preventing color mix by using color filters and a color pattern on the encapsulation layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a polarizing plate is used in OLED display devices, then external light reflection is reduced and visibility is enhanced, but cost increases and brightness is reduced
Solution Approach 1:
The patent employs a photochromic layer that changes its optical properties (transparency/opaqueness) in response to light wavelength. This layer replaces the polarizing plate and achieves anti-reflection functionality through wavelength-dependent optical transitions rather than polarization filtering, thereby maintaining brightness while reducing external light reflection
Solution Approach 2:
The patent utilizes the photochromic layer's ability to change its optical parameters (transmission characteristics) based on incident light wavelength. By controlling the optical state of the photochromic layer through wavelength selection, the system achieves both anti-reflection and brightness maintenance without requiring a polarizing plate
2Object-affected harmful factors
If a polarizing plate is used in OLED display devices, then external light reflection is reduced, but cost increases
Solution Approach 1:
The patent replaces the expensive polarizing plate with a photochromic layer that can be integrated into the existing OLED structure. The photochromic layer uses cost-effective materials and simpler manufacturing processes while achieving the same anti-reflection functionality, thereby reducing production cost
Solution Approach 2:
The patent extracts and removes the polarizing plate from the OLED display structure, eliminating the need for this expensive component. The functionality previously provided by the polarizing plate is achieved through the photochromic layer, which is less costly and easier to manufacture
3Ease of manufacture
If no black matrix is used, then manufacturing is simplified, but color mix occurs between different emission areas
Solution Approach 1:
The patent introduces a color pattern layer with locally differentiated optical properties that corresponds to different emission areas. This layer provides spatially selective color filtering, preventing color mix between adjacent emission areas while maintaining manufacturing simplicity by using a planar structure that can be easily fabricated
Solution Approach 2:
The patent introduces a color pattern layer as an intermediary between the emission areas and the viewer. This intermediate layer filters and directs light from different emission areas, preventing color mixing while allowing each area to maintain its distinct color output without requiring a complex black matrix structure
4Adaptability or versatility
If field-of-view is improved, then viewing angle is enhanced, but external light reflectance increases
Solution Approach 1:
The patent employs a dynamic photochromic layer that adapts its optical properties based on the viewing angle and incident light conditions. The layer transitions between transparent and opaque states in response to wavelength changes, enabling wide field-of-view while dynamically controlling external light reflection to maintain visibility
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 solution provides improved field-of-view, reduced external light reflectance, and enhanced color characteristics, maintaining brightness and clarity whether viewed from the front or side without the need for a polarizing plate, thus addressing the cost and brightness issues of traditional OLED displays.
Implementation Method 1
a photochromic layer disposed on the encapsulation layer, and overlapping a portion of the bank. When a first wavelength band of light is irradiated to the photochromic layer, the photochromic layer is in a transparent state. When a second wavelength band of light is irradiated to the photochromic layer, the photochromic layer is in an opaque state, the second wavelength band being shorter than the first wavelength band
Data Source
AI summary
A light emitting display panel includes a first emission area, a second emission area, and a third emission area spaced apart from each other and emitting different colors of light and a photochromic layer surrounding each of the first, second, and third emission areas and disposed in a non-emission area. When the first emission area, the second emission area, and the third emission area emit light, the photochromic layer is in a transparent state. When light of a wavelength band shorter than visible light is incident on the photochromic layer, the photochromic layer is in an opaque state.