Dummy Pixel Thin Film Analysis for OLED Defect Detection
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Solution Overview
Problem
Existing methods for analyzing defects in thin films of organic light emitting displays often damage the films, making it difficult to determine the cause of defects and electrical characteristics.
Innovation Solution
A light emitting display device with a substrate featuring a thin film transistor, an organic light emitting diode, and dummy pixels formed of the same material as the semiconductor, gate, and source/drain electrodes, allowing for analysis without damaging the thin films, along with a method for manufacturing this device that includes forming and exposing dummy patterns on the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the insulating layer is decapped to expose electrodes for signal measurement, then signal measurement becomes possible, but the thin film is damaged
Solution Approach 1:
The substrate is divided into a pixel region and a non-pixel region. The non-pixel region contains dummy patterns that are exposed through openings in the insulating layer, allowing measurement without exposing the thin film in the pixel region. This segmentation separates the measurement function from the display function.
Solution Approach 2:
Dummy patterns are introduced as intermediary structures in the non-pixel region. These dummy patterns serve as mediators that allow electrical signal measurement and thin film analysis without directly exposing or damaging the functional thin film in the pixel region. The dummy patterns replicate the thin film structure to enable indirect measurement.
2Productivity
If a test pattern is formed in a non-pixel region to test thin film transistor characteristics, then electrical characteristics can be tested, but the fundamental causes of defects in thin films cannot be determined
Solution Approach 1:
Dummy patterns are created as copies of the thin film structures (semiconductor layer, gate electrode, source/drain electrodes, anode) in the non-pixel region. These copied structures allow measurement and analysis without affecting the original pixel region thin films. The dummy patterns replicate the material composition and layer structure to enable defect analysis.
Solution Approach 2:
The measurement and analysis function is moved to another dimension - the non-pixel region - rather than exposing the thin film in the pixel region. By placing dummy patterns in the non-pixel region and exposing only those through openings, the system enables comprehensive thin film analysis while preserving the integrity of the pixel region thin films.
3Ease of operation
If thin films are removed to expose electrodes for measurement, then electrode signals can be probed, but it becomes difficult to determine electrical characteristics of the thin film
Solution Approach 1:
Dummy patterns are formed preliminarily in the non-pixel region during the manufacturing process, before final assembly. These dummy patterns are prepared in advance with the same thin film structures as the pixel region, enabling subsequent measurement of thin film electrical characteristics without requiring removal or damage to the functional thin films.
Data Source
AI summary
Disclosed are a light emitting display and a method for fabricating the same. The light emitting display includes a substrate. A thin film transistor is formed on a first region of the substrate, and includes a semiconductor layer, a gate electrode, and source/drain electrodes. An organic light emitting diode is electrically coupled to the thin film transistor and includes a first electrode, an emission layer, and a second electrode. A dummy pixel, formed in a second region of the substrate, includes at least one dummy pattern. The dummy pattern is formed of the same material as that of one of the semiconductor layer, the gate electrode, the source/drain electrodes, and the first electrode.