OLED Subpixel Electrode Structure for Light Leakage Control
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Solution Overview
Problem
Existing organic light emitting display devices face issues with light leakage between sub pixels, particularly when a color filter is not formed in adjacent areas, leading to color and emission level changes, which affects display quality.
Innovation Solution
The solution involves forming a second electrode on the color filter or organic light emitting element in the boundary area of sub pixels, with a vertical structure to minimize light reflection and leakage, and omitting the overcoat and bank in these areas to allow direct contact between the electrode and color filter, ensuring light is absorbed or passed through the filter rather than reflected to adjacent pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a color filter is formed in sub pixel areas, then color display quality is improved, but light leakage occurs into adjacent sub pixel areas where color filters are not formed
Solution Approach 1:
The patent divides the display panel into distinct sub pixel areas with color filters and non-sub pixel areas without color filters. By segmenting the overcoat layer and forming separate bank structures at boundaries, the patent creates isolated regions that prevent light from leaking between adjacent sub pixels, thereby maintaining color display quality while eliminating light leakage issues.
Solution Approach 2:
The patent applies different structural configurations to different regions: color filters are formed only in sub pixel areas, while overcoat and bank structures are strategically positioned at boundaries. This local differentiation ensures that light reflection is controlled specifically at boundary regions where leakage occurs, without affecting the color display quality in the sub pixel areas themselves.
2Strength
If overcoat and bank are formed in boundary areas, then structural support is improved, but light leakage prevention is reduced
Solution Approach 1:
The patent extracts or removes the overcoat and bank structures from the boundary areas between sub pixels. By taking out these light-reflecting structures from critical boundary regions, the patent eliminates the source of light leakage while maintaining sufficient structural support within the sub pixel areas where color filters are formed.
Solution Approach 2:
The patent introduces a vertical electrode structure as an intermediary element that extends from the substrate through the organic light emitting layer to contact the color filter. This vertical structure serves as a mediator that blocks light paths at the boundary while maintaining electrical connectivity, thus preventing light leakage without compromising structural integrity.
3Object-generated harmful factors
If electrode is formed directly on color filter, then light reflection is minimized, but manufacturing precision requirements increase
Solution Approach 1:
The patent transitions from a planar electrode configuration to a vertical three-dimensional structure. The electrode extends vertically from the substrate through the organic light emitting layer to contact the color filter directly. This dimensional change allows the electrode to minimize light reflection by contacting the color filter at its boundary while maintaining manufacturability through standard vertical deposition processes.
Solution Approach 2:
The patent forms the color filter structure and defines its boundary area before forming the electrode. This preliminary action establishes a precise reference structure that guides subsequent electrode formation, ensuring accurate alignment and contact between the electrode and color filter boundary while maintaining manufacturing precision through a sequential fabrication process.
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 effectively prevents light leakage and color mixing, enhancing display accuracy and reducing stitch spots by ensuring light is either absorbed or transmitted through the color filter, thereby improving color consistency and display quality.
Implementation Method 1
a color filter is adhered to or in contact with an electrode (e.g. a cathode) such that light reflected from the electrode is input to the color filter again in order to prevent a light leakage
Data Source
AI summary
The present invention relates to an organic light emitting display device and a method of manufacturing the same. An aspect of the present invention provides an organic light emitting display device comprising: a pixel area that includes a plurality of first electrodes (250) connected to a source electrode or a drain electrode of a thin film transistor, and includes two or more sub pixel areas (591,592); a first sub pixel area (591) where a color filter (230) is positioned in the pixel area; a second sub pixel area (592) that is adjacent to the first sub pixel area (591); an overcoat (341,342) that is positioned and disconnected between the first sub pixel area (591) and the second sub pixel area (592); a first bank (361a) that is positioned at a boundary of the first sub pixel area (591); and a second bank (361b) that is positioned at a boundary of the second sub pixel area (592).