OLED Transflective Electrode Suppressing External Light Reflection
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Solution Overview
Problem
Conventional OLED displays with touch panels face issues with light reflection from external sources, which degrade display characteristics such as black color expression and contrast, and the use of polarizing and phase delay plates leads to light loss and increased thickness, making them unsuitable for thin and lightweight designs.
Innovation Solution
The implementation of a transflective common electrode with low reflectivity, made from materials like magnesium (Mg) and silver (Ag), and an encapsulation thin film with a high refractive index, along with a touch panel structure that includes a first and second touch conductive layer, effectively suppresses external light reflection through destructive interference, eliminating the need for additional light-suppressing components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a polarizing plate and a phase delay plate are used to suppress reflected light, then the display characteristics are improved, but the device thickness increases and light loss occurs
Solution Approach 1:
The invention extracts and removes the polarizing plate and phase delay plate from the OLED display structure, replacing them with a transflective common electrode that has specific reflective properties. This eliminates the need for separate light-suppressing components while maintaining the desired anti-reflection functionality.
Solution Approach 2:
The transflective common electrode serves multiple functions: it acts as the common electrode for the OLED, provides the anti-reflection property through its specific reflectivity (5-40%), and eliminates the need for separate polarizing and phase delay plates. This multi-functional design reduces device thickness while maintaining display characteristics.
2Object-affected harmful factors
If a polarizing plate and a phase delay plate are used to suppress reflected light, then the display characteristics are improved, but light loss occurs
Solution Approach 1:
Instead of using plates that absorb or block reflected light (causing light loss), the invention converts the reflective property into a beneficial feature by designing the common electrode with specific reflectivity (5-40%). This controlled reflection, combined with the encapsulation layer's interference effect, suppresses external light reflection while preserving the OLED's self-generated light.
3Reliability
If the common electrode is made highly reflective, then the OLED performance is improved, but external light reflection increases
Solution Approach 1:
The invention changes the reflectivity parameter of the common electrode from traditional high reflectivity to a specific range (5-40%). This parameter modification, combined with the encapsulation layer's refractive index and thickness, creates destructive interference for external light while maintaining sufficient reflectivity for OLED operation.
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 solution enhances the visibility of OLED displays by reducing external light reflection while maintaining a suitable thickness for use with touch panels, improving display characteristics and eliminating the need for bulky light-suppressing plates.
Implementation Method 1
effectively suppresses external light reflection through destructive interference
Implementation Method 2
Light is emitted as excitons are generated. The excitons are generated as electrons and holes are combined and drop from an excited state to a ground state.
Data Source
AI summary
An organic light emitting diode (OLED) display is provided. The OLED display includes: a substrate member; an OLED that includes a pixel electrode that is formed on the substrate member, an organic light emitting layer that is formed on the pixel electrode, and a transflective common electrode that is formed on the organic light emitting layer; an encapsulation thin film that is formed on the transflective common electrode; and a touch panel that includes a first touch conductive layer that is formed on the encapsulation thin film and that is formed with a transflective metal film, a glass substrate that is formed on the first touch conductive layer, and a second touch conductive layer that is formed on the glass substrate. In some embodiments, the transflective common electrode has reflectivity of less than 50%. Some of the external light is thus reflected again to the first touch conductive layer and back to the transflective common electrode and so on. During this cycling, destructive interference occurs and the cycled light eventually dissipates. Thus, unwanted reflected light is suppressed.