In-Pixel Compensation Timing for Display Current Droop
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electronic displays with self-emissive pixels, such as μLEDs, experience current droop due to inherent electrical resistance and capacitive coupling, leading to visible image artifacts like banding, especially exacerbated by touch sensor operations.
Innovation Solution
Implement pixel compensation by refreshing storage capacitors to reduce or eliminate current droop, and adjust the pattern of compensation across subframes to maintain consistent light emission, reducing power consumption and artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pixel compensation is performed on each pixel in each subframe, then current droop is reduced or eliminated, but power consumption becomes excessive
Solution Approach 1:
The patent applies partial action by performing pixel compensation selectively on only some pixels in each subframe rather than all pixels. Specifically, pixels are divided into groups and compensation is applied to one group per subframe, rotating through different groups in subsequent subframes. This partial compensation approach reduces power consumption while still achieving acceptable current uniformity across the display.
Solution Approach 2:
The patent implements periodic action by cycling through different pixel groups for compensation across multiple subframes. Each pixel group receives compensation periodically rather than continuously, creating a temporal pattern where compensation is distributed evenly across all pixels over time. This periodic approach maintains display quality while reducing instantaneous power demands.
2Object-affected harmful factors
If pixel compensation is performed on every pixel, then image artifacts are eliminated, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the pixel array into multiple groups or zones, where each group is compensated separately in different subframes. This segmentation allows the compensation circuit to operate on a subset of pixels at any given time, reducing the instantaneous complexity and resource requirements while still addressing artifacts across the entire display over time.
Solution Approach 2:
The patent uses partial action by implementing compensation on only a portion of pixels in each subframe rather than all pixels simultaneously. This selective compensation reduces the complexity of compensation circuits and control logic while maintaining acceptable image quality through the periodic rotation of compensated pixel groups.
3Productivity
If microdriver drives subsequent pixels in row, then complete image can be displayed, but current droop causes banding artifacts
Solution Approach 1:
The patent applies preliminary action by performing compensation on selected pixels before they are driven and displayed. By pre-charging storage capacitors on pixels that will be driven in subsequent subframes, the system compensates for anticipated current droop before it occurs, preventing banding artifacts while maintaining complete image display capability.
Solution Approach 2:
The patent implements feedback by using information about pixel position and drive sequence to determine which pixels require compensation in each subframe. The compensation strategy is based on feedback from the driving pattern, targeting pixels that are most susceptible to current droop based on their position in the drive sequence and row.
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 effectively minimizes current droop and associated image artifacts while optimizing power usage, ensuring consistent display quality across the electronic display.
Implementation Method 1
capacitive coupling at the microdriver may lead to distortion on the microdriver. In particular, the capacitive coupling may cause distortion at a storage capacitor
Implementation Method 2
As subsequent pixels in the row are driven, inherent electrical resistance in the pixels and conductors coupling the pixels may cause a current droop or a current rise in the subsequent pixels in the row
Data Source
AI summary
An electronic device may include an electronic display including display pixels to display an image based on compensated image data. As image data is written to a pixel in the row of pixels, capacitive coupling at a driver may lead to distortion on the driver. In particular, the capacitive coupling may cause distortion at a storage capacitor, which may lead to current droop at the pixel. The current droop may be reduced or eliminated in each pixel by performing pixel compensation. The pattern of the pixel compensation may be selected such that, over a number of subframes, an average amount of light is the same or similar to what would be emitted had pixel compensation been performed on each pixel in each subframe.