Organic Light-Emitting Display Cathode Transmittance and Uniformity
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Solution Overview
Problem
Existing organic light-emitting displays face limitations in transmittance due to the metal composition of the cathode, making it difficult to achieve high external light transmittance while maintaining a uniform cathode thickness.
Innovation Solution
A thin film deposition apparatus is designed to form a penetration unit in the panel, allowing light to pass through while ensuring a uniform cathode thickness, using a blocking member with a fan shape to control the deposition of the cathode material at an angle less than 90 degrees, and a method of manufacturing organic light-emitting displays that includes a substrate with separate areas for light emission and penetration, where the cathode is deposited with an opening on one side to enhance transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal cathode is used in the organic light-emitting display, then the cathode provides good electrical conductivity, but the transmittance of the display is limited
Solution Approach 1:
The cathode is segmented into multiple regions: a first cathode region with higher thickness for electrical connection and a second cathode region with lower thickness for light transmittance. This segmentation allows different parts of the cathode to serve different functions - the first region ensures good electrical conductivity while the second region maintains high transmittance, thus resolving the contradiction between conductivity and transmittance.
2Illumination intensity
If the cathode thickness is reduced to improve transmittance, then light can pass through more easily, but the uniformity of cathode thickness becomes difficult to maintain
Solution Approach 1:
Different regions of the cathode are assigned different thickness qualities to meet local functional requirements. The first cathode region has a greater thickness range (first minimum thickness to first maximum thickness) optimized for electrical conductivity, while the second cathode region has a smaller thickness range (second minimum thickness to second maximum thickness) optimized for light transmittance. This local quality differentiation allows each region to achieve its optimal performance without compromising overall cathode uniformity.
3Manufacturing precision
If additional masking steps are added to pattern the cathode, then the cathode can be precisely patterned, but the manufacturing process complexity increases
Solution Approach 1:
The deposition process itself is used to create the patterned cathode structure by controlling the deposition conditions (such as substrate rotation speed, deposition rate, and temperature) to naturally form different thickness regions. This self-service approach eliminates the need for additional masking steps, as the cathode patterns are formed directly during the deposition process through precise control of deposition parameters, thus reducing manufacturing process complexity while maintaining patterning precision.
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
The solution achieves high external light transmittance and a uniform cathode thickness, improving the manufacturing process by patterning the cathode without additional masking steps, thereby increasing the overall transmittance of the organic light-emitting display.
Implementation Method 1
a deposition source spaced apart from a center of the substrate and emitting a deposition material toward the substrate
Implementation Method 2
a blocking member disposed on the substrate, including an opening on at least one side, and blocking at least a part of the deposition material emitted from the deposition source
Data Source
AI summary
A thin film deposition apparatus, which has high external light transmittance and a cathode having a uniform thickness, is disclosed. In one embodiment, the thin film deposition apparatus includes a deposition source spaced apart from a center of the substrate and configured to emit a deposition material toward the substrate and a blocking member disposed on the substrate and configured to block at least part of the deposition material emitted from the deposition source, wherein an opening is defined on at least one side of the blocking member.