EVDD Adjustment Circuit for Electroluminescent Display
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Solution Overview
Problem
Electroluminescent display devices experience motion blurring due to longer motion picture response time and charging timing interference between black and input images, making it difficult to represent a stable black image with visible bright or dark lines in specific pixel lines.
Innovation Solution
An electroluminescent display device with an EVDD adjustment circuit that cuts off the high-level power supply voltage during a black period in one frame, preventing the high-level power supply voltage from being applied to pixels, thereby eliminating charging interference and ensuring a stable black image representation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If black image data is inserted to improve MPRT and minimize motion blurring, then motion picture response time is improved, but charging timing interference occurs between black image and input image causing unstable black image representation and visible bright/dark lines in specific pixel lines
Solution Approach 1:
The patent segments the power supply control by pixel line, dividing the display panel into multiple pixel line groups (first pixel line group and second pixel line group). Each group receives power supply control independently through separate control signals (first EVDD control signal and second EVDD control signal), allowing staggered black image periods for different groups. This segmentation eliminates charging timing interference while maintaining improved motion picture response time.
Solution Approach 2:
The patent implements periodic black image periods for different pixel line groups. The first pixel line group has a black image period during a first period, while the second pixel line group has a black image period during a second period. This periodic staggering ensures that not all pixel lines update simultaneously, preventing charging timing interference and eliminating visible bright/dark lines while maintaining the motion picture response time benefits.
2Object-affected harmful factors
If black image data is inserted to minimize motion blurring, then motion blurring is reduced, but bright lines and dark lines different from normal luminance are visibly recognized in specific pixel lines
Solution Approach 1:
The patent segments the pixel lines into multiple groups with different black image timing. By controlling the EVDD power supply to different pixel line groups at different times, it prevents the simultaneous charging interference that causes bright/dark lines in specific pixel lines, thereby maintaining luminance uniformity across the display while still reducing motion blurring.
Solution Approach 2:
The patent dynamically adjusts the black image period timing for different pixel line groups. Instead of a static uniform black image period for all pixels, the system applies dynamic time-staggered black periods to different pixel line groups, adapting the timing to eliminate visible luminance deviations while maintaining motion picture response improvements.
Data Source
AI summary
An electroluminescent display device includes a display panel including a plurality of pixels each including a light-emitting element driven according to a driving current flowing between a high-level power supply voltage and a low-level power supply voltage, and an EVDD adjustment circuit configured to cut off the high-level power supply voltage for a black period in which emission of light from the light-emitting element stops in one frame such that the high-level power supply voltage is not applied to the pixels.