Pixel Driving Circuit with Dual Storage Capacitors for AMOLED IR Drop Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In AMOLED display panels, uneven display luminance occurs due to varying wire resistance, leading to different current and brightness outputs across pixels under the same data signal voltage, resulting in inconsistent display brightness.
Innovation Solution
A pixel driving circuit is introduced, comprising switching elements and storage capacitors that maintain a constant voltage difference across the driving transistor, mitigating the influence of IR drop and ensuring uniform brightness by mirroring the power signal change and compensating for threshold voltage offsets, thereby stabilizing current output across all pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple driving circuit is used in AMOLED display panels, then the manufacturing cost is reduced and the structure is simplified, but the display luminance becomes uneven due to wire resistance variations
Solution Approach 1:
The patent introduces a dual-capacitor configuration (first storage capacitor connected to gate, second storage capacitor connected to source) that dynamically adjusts voltage parameters to compensate for IR drop. The capacitors maintain stable voltage levels despite wire resistance variations, ensuring uniform luminance across the display panel while keeping the driving circuit relatively simple.
Solution Approach 2:
The patent uses storage capacitors as intermediary elements between the power supply and the driving transistor. These capacitors act as local energy reservoirs that buffer voltage fluctuations caused by wire resistance, thereby mediating the relationship between power delivery and pixel output to achieve uniform brightness.
2Area of stationary object
If the display panel size is increased for larger screens, then the viewing area is expanded, but the wire resistance increases causing greater IR drop and more severe luminance non-uniformity
Solution Approach 1:
The dual-capacitor circuit dynamically adjusts voltage parameters to compensate for increased IR drop in larger displays. The first storage capacitor maintains gate voltage stability while the second storage capacitor compensates for source voltage variations, ensuring that even in large-area displays, the voltage difference across the driving transistor remains consistent despite longer wire paths.
Solution Approach 2:
The patent creates equipotential conditions at the transistor level by using storage capacitors to maintain stable voltage references. This local equipotential approach counteracts the cumulative effect of wire resistance across large display areas, ensuring uniform current distribution and luminance across the entire panel.
3Device complexity
If the data signal voltage is kept constant across all pixels, then the driving circuit is simplified, but the current output varies due to threshold voltage offsets causing brightness inconsistency
Solution Approach 1:
The patent uses the dual-capacitor configuration to dynamically adjust voltage parameters that compensate for threshold voltage offsets. By maintaining a stable voltage difference between gate and source through the capacitors, the circuit ensures consistent current output despite variations in transistor threshold voltages, achieving uniform brightness without complicating the overall driving circuit architecture.
Solution Approach 2:
The storage capacitors provide a form of negative feedback by maintaining stable voltage references that counteract threshold voltage variations. The capacitors charge to voltages that automatically compensate for device parameter variations, creating a self-regulating mechanism that ensures consistent pixel brightness across the display.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present disclosure provides a pixel driving circuit and a driving method, a display device. The driving circuit includes: a first switching element, a second switching element, a third switching element, a fourth switching element, a fifth switching element, a driving transistor, a sixth switching element, a first storage capacitor and a second storage capacitor. The present disclosure can ensure the uniformity of the output current, thereby eliminating the influence of the IR drop of the power line on the display brightness, and ensuring the uniformity of the display brightness of each pixel.