Plasma Display Driving Method for Luminance Uniformity
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Solution Overview
Problem
Plasma display devices experience luminance deviations due to varying line load ratios, affecting the uniformity of grayscale display across the screen, as the number of turn-on cells along row electrodes influences discharge currents and voltage drops, leading to inconsistent luminance across different phosphor colors.
Innovation Solution
A driving method that compensates for luminance deviations by calculating and updating subfield weights based on line load ratios and screen load ratios, using models that consider the impact of line load ratios, screen load ratios, and phosphor colors to adjust the number of sustain pulses applied to each subfield, ensuring consistent luminance across the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the number of turn-on cells along row electrodes is increased to improve display coverage, then the display area is improved, but voltage drop increases and luminance uniformity deteriorates
Solution Approach 1:
The patent applies local quality by adjusting sustain pulse weights individually for each row electrode based on its specific line load ratio. Instead of using a uniform sustain pulse for all rows, the system calculates the line load ratio for each row (number of turn-on cells divided by total cells) and applies corresponding weight adjustments to compensate for voltage drops, thereby achieving uniform luminance across different regions of the display.
Solution Approach 2:
The patent changes the parameter of sustain pulse weight according to the line load ratio. By varying the weight parameter based on the calculated line load ratio for each row electrode, the system dynamically adjusts the discharge characteristics to compensate for voltage drops caused by different numbers of turn-on cells, thus maintaining luminance uniformity while preserving full display area.
2Manufacturing precision
If sustain pulse weight is increased to compensate for voltage drop, then luminance uniformity is improved, but energy consumption increases
Solution Approach 1:
The patent applies parameter changes by adjusting sustain pulse weights based on the line load ratio for each row electrode. The weight adjustment is proportional to the voltage drop caused by the line load, ensuring that energy is increased only where necessary to compensate for voltage drops, rather than uniformly increasing energy consumption across the entire display.
Solution Approach 2:
The system applies local quality by tailoring sustain pulse weights to specific row electrodes based on their individual line load ratios. This localized adjustment ensures that energy compensation is applied only to rows experiencing voltage drops, avoiding unnecessary energy consumption in rows with low line loads while maintaining luminance uniformity where needed.
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 method effectively reduces luminance errors and maintains consistent grayscale representation across the screen by recalculating and adjusting subfield weights, thereby improving the uniformity of display luminance regardless of line load ratios, enhancing the visual quality of plasma display devices.
Implementation Method 1
A plasma display device is a flat panel display device that uses plasma generated by a gas discharge process to display characters or images
Implementation Method 2
Phosphor layers of red, green, and blue are alternately formed along a row direction and corresponding to the A electrodes A1 to Am
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4B
AI summary
In a plasma display device, one frame is divided into a plurality of subfields having respective luminance weights, and a first line load ratio is measured from a plurality of video signals corresponding to a first row electrode among a plurality of row electrodes during the respective subfields. A first output estimation weight of each subfield is set based on the first line load ratio of each subfield in the first row electrode. The plurality of video signals corresponding to the first row electrode are converted into a plurality of first subfield data based on the first output estimation weight, and a driving signal is applied to the first row electrode and the plurality of column electrodes according to the plurality of first subfield data.