Display PWM Pulse Width Control for Uniform Frame Brightness
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Solution Overview
Problem
Conventional display panels suffer from brightness uniformity issues due to identical active pulse widths of light-emission control signals, leading to flicker phenomena.
Innovation Solution
A pulse width modulation method that adjusts active pulse widths within refresh and maintenance frames to ensure equal brightness values, by increasing pulse widths beyond certain thresholds in refresh frames and decreasing them below thresholds in maintenance frames.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If active pulse widths of light-emission control signals are kept identical in conventional display panels, then the control signal generation is simple, but brightness uniformity deteriorates and flicker occurs
Solution Approach 1:
The patent applies local quality by differentiating pulse width characteristics across different spatial locations (refresh frame vs. maintenance frame) and temporal positions. Specifically, the refresh frame uses a first pulse width characteristic while the maintenance frame uses a second pulse width characteristic, creating localized variations in signal properties to achieve uniform brightness across different display regions and time periods.
2Illumination intensity
If active pulse widths are adjusted differently in refresh and maintenance frames, then brightness uniformity is improved and flicker is prevented, but signal control complexity increases
Solution Approach 1:
The patent implements periodic action by establishing a repeating display period that alternates between refresh frames and maintenance frames, each with specific pulse width characteristics. This periodic structure allows the system to systematically vary pulse widths in a predictable pattern, ensuring brightness uniformity while managing control complexity through regular, repeating signal sequences.
Solution Approach 2:
The patent applies dynamics by making the pulse width characteristics adaptable and variable rather than fixed. The system dynamically adjusts pulse widths based on the frame type (refresh or maintenance), allowing flexible control of brightness characteristics. This dynamic approach enables the display to respond to different operational requirements while maintaining overall brightness uniformity.
3Use of energy by moving object
If refresh rate is decreased to reduce power consumption, then energy efficiency is improved, but brightness uniformity deteriorates and flicker increases
Solution Approach 1:
The patent applies parameter changes by modifying the pulse width parameter in response to refresh rate changes. When the refresh rate is decreased to save power, the system adjusts the pulse width characteristics in refresh and maintenance frames to compensate for the reduced refresh frequency. This parameter adaptation ensures that brightness uniformity is maintained even at lower power consumption levels.
Data Source
AI summary
The present disclosure provides a pulse width modulation method, a pulse width modulation module and a display device. A display panel includes a pixel circuitry configured to receive a light-emission control signal and control a light-emitting element to emit light under the control of the light-emission control signal, and a display period includes a refresh frame and a maintenance frame. The pulse width modulation method includes: increasing at least one active pulse width of the light-emission control signal within the refresh frame so that the at least one active pulse width of the light-emission control signal is larger than a first active pulse width threshold; and/or decreasing at least one active pulse width of the light-emission control signal within the maintenance frame so that the at least one active pulse width of the light-emission control signal is less than a second active pulse width threshold.