Light-emitting device holding capacitor placement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light-emitting devices with holding capacitors outside the display region lead to enlarged non-display areas, which is inefficient in terms of space utilization and can affect the overall size and functionality of micro-sized pixel circuits.
Innovation Solution
Incorporating capacitors within the display region, specifically a holding capacitor and a transfer capacitor, along with a fixed potential metal layer between them, to manage gradation voltages and reduce non-display area usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the holding capacitor is provided in the portion other than the display region, then the pixel circuit can be driven properly, but the non-display region is enlarged
Solution Approach 1:
The holding capacitor is moved from the planar non-display region into the vertical dimension by placing it within the display region at a different layer level, specifically utilizing the space between the first and second capacitors in the stacked configuration. This allows the capacitor to occupy vertical space rather than horizontal space, resolving the contradiction between reliable pixel driving and minimizing non-display region area.
Solution Approach 2:
The holding capacitor is nested within the display region by positioning it between the first capacitor (connected to the data signal supply circuit) and the second capacitor (connected to the data line). This nested arrangement allows the holding capacitor to share the display region space with other circuit elements, eliminating the need for separate non-display region placement while maintaining proper pixel circuit driving functionality.
2Area of stationary object
If capacitors are integrated within the display region, then the non-display area is reduced, but the circuit layout becomes more complex
Solution Approach 1:
The circuit is segmented into distinct functional blocks with clearly defined connections: the first capacitor connected to the data signal supply circuit, the holding capacitor positioned between them, and the second capacitor connected to the data line. This segmentation approach, combined with the fixed potential metal layer providing a common reference, simplifies the overall layout planning by creating modular units that can be systematically arranged within the display region.
Solution Approach 2:
A metal layer supplied with a fixed potential is disposed between the first capacitor and the second capacitor, creating an equipotential reference plane. This equipotential structure simplifies the circuit layout by providing a stable voltage reference that reduces interference and simplifies connection routing, thereby reducing layout complexity while enabling compact integration within the display region.
3Device complexity
If the holding capacitor is placed outside the display region, then the circuit design is simpler, but the overall device area increases
Solution Approach 1:
The holding capacitor function is merged with the display region circuit elements by positioning it between the first capacitor and the second capacitor within the display region. This merging eliminates the need for separate non-display region placement, thereby reducing the overall device area while maintaining the holding capacitor's essential function for proper pixel circuit operation through its strategic positioning in the signal path.
Data Source
AI summary
A light-emitting device includes a data signal supply circuit, a first switching element electrically coupled to the data signal supply circuit, a first capacitor disposed in a display region and electrically coupled to the first switching element, a second switching element including a first end electrically coupled to the first switching element, and a second end, a second capacitor disposed in the display region and including a first end electrically coupled to the second end of the second switching element, and a second end, a data line electrically coupled to the second end of the second capacitor, a pixel circuit electrically coupled to the data line, and a first metal layer disposed between the first capacitor and the second capacitor and supplied with a fixed potential.