Transparent OLED Cathode Window Layout for Clear External Viewing
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Solution Overview
Problem
Transparent organic light emitting display devices face limitations in increasing transmittance due to the metal cathode, which restricts the ability to clearly observe external images.
Innovation Solution
The design incorporates a substrate with pixels having a first region for light emission and a second region for transmitting external light, featuring thin film transistors and electrodes with transmission windows in the second electrode, allowing for enhanced transmittance without interference from light-emitting devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a metal cathode is used in transparent organic light emitting display devices, then the device structure is simple and manufacturing is easier, but the transmittance of external light is reduced
Solution Approach 1:
The cathode is divided into multiple segments: a transparent conductive oxide layer (first cathode layer) and a metal layer (second cathode layer) with transmission windows. This segmentation allows different regions to serve different functions - the transparent oxide provides conductivity while the metal layer with windows provides both conductivity and light transmission paths
Solution Approach 2:
The metal layer is configured with local quality variations through transmission windows that are strategically positioned. The metal layer has different properties in different regions: continuous metal for conductivity in non-display areas, and discontinuous metal with windows in display areas to allow light transmission while maintaining electrical connection
2Illumination intensity
If the transmittance of the second region is increased to allow external light transmission, then external images can be observed, but light-emitting devices may cause distortion or interference
Solution Approach 1:
The pixel structure is segmented into a first region for light emission containing light-emitting devices and a second region for external light transmission. This spatial segmentation ensures that the transmission windows are positioned only in the second region, preventing interference from light-emitting devices while maintaining high transmittance for external images
Solution Approach 2:
The transparent conductive oxide layer serves as an intermediary between the metal layer and the external environment. It provides electrical conductivity and charge injection functionality while being transparent to external light, thus mediating between the need for electrical performance and optical transparency without causing distortion
Data Source
AI summary
An organic light emitting display device having high transmittance with respect to external light and a method of manufacturing the same. The organic light emitting display device includes a substrate; a plurality of pixels formed on the substrate, each of the pixels including a first region that emits light and a second region that transmits external light; a plurality of thin film transistors disposed in the first region of each pixel; a plurality of first electrodes disposed in the first region of each pixel and electrically connected to the thin film transistors, respectively; a second electrode formed opposite to the plurality of first electrodes and comprising a plurality of transmission windows corresponding to the second regions; and an organic layer formed between the first electrodes and the second electrode. The transmission windows can be formed in the second electrode, that is, a cathode.