Black Matrix Light Blocking in Organic Light Emitting Displays
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Solution Overview
Problem
Conventional organic light emitting display devices face reduced contrast due to external light reflection from metallic materials, which is often mitigated by using an expensive polarizing plate, increasing manufacturing costs and reducing luminance.
Innovation Solution
Incorporating a black matrix on a first insulating layer, extending into pixel-separating regions, to block external light and light emitted from the display unit, thereby reducing reflection without the need for a polarizing plate, and using materials like chromium or molybdenum films for effective light blocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a polarizing plate is attached to the front of the display device to minimize external light reflection, then contrast is improved, but manufacturing cost increases and luminance is reduced
Solution Approach 1:
The patent extracts and removes the polarizing plate from the display structure, replacing it with a black matrix layer that performs the light-blocking function without the need for polarization filtering. This eliminates the harmful reflection issue while avoiding the costs and luminance loss associated with polarizing plates.
Solution Approach 2:
The patent uses a black matrix layer made from inexpensive materials such as chromium, molybdenum, or their oxides/alloys as a replacement for the expensive polarizing plate. This cheap alternative achieves the same light-blocking function without the additional costs and luminance reduction.
2Object-affected harmful factors
If a polarizing plate is attached to the front of the display device to minimize external light reflection, then contrast is improved, but luminance is reduced
Solution Approach 1:
The patent extracts and removes the polarizing plate from the display structure, replacing it with a black matrix layer that performs the light-blocking function without the need for polarization filtering. This eliminates the harmful reflection issue while avoiding the costs and luminance loss associated with polarizing plates.
3Ease of manufacture
If the display device structure is simplified without a polarizing plate, then manufacturing cost is reduced, but external light reflection increases
Solution Approach 1:
The black matrix layer serves multiple functions: it acts as a light-blocking layer to prevent external light reflection, serves as a structural element in the display architecture, and provides a base for subsequent layers. This multi-functional approach achieves reflection reduction without increasing manufacturing complexity.
Solution Approach 2:
The patent uses a black matrix layer that copies or replicates the light-blocking function of the polarizing plate but implements it through a different mechanism (absorption rather than polarization). This functional copying achieves the same effect with simpler, cheaper materials.
4Object-affected harmful factors
If the black matrix extends into the pixel-separating region, then light blocking is improved, but device complexity increases
Solution Approach 1:
The patent merges the black matrix layer with the pixel-separating region structure, extending the black matrix into the pixel-separating region to simultaneously achieve light blocking and structural definition. This integration improves light blocking effectiveness while avoiding the need for separate complex components.
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 effectively minimizes external light reflection and light interference with photosensitive elements, enhancing contrast and reliability while maintaining luminance without the use of a polarizing plate.
Implementation Method 1
a black matrix between the first insulating layer and the pixel definition layer extending outwardly past an edge region of the pixel definition layer into the pixel-separating region
Data Source
AI summary
An organic light emitting display for minimizing light from entering the pixels is provided. The organic light emitting display includes a substrate including a pixel region and a pixel-separating region between pixel regions; a first insulating layer on the substrate; a first electrode in a pixel region and on the first insulating layer; a pixel definition layer overlapping an edge region of the first electrode and in a region between the pixel region and the pixel-separating region; an organic light emitting layer on the first electrode and the pixel definition layer; a second electrode on the organic light emitting layer; and a black matrix between the first insulating layer and the pixel definition layer and extending outwardly past an edge region of the pixel definition layer into the pixel-separating region, such that the pixel definition layer is separated from the first insulating layer.