AMOLED Emission Driver Pulse Control for Fine Dimming
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Solution Overview
Problem
Existing display devices face challenges in finely adjusting the off period ratio of pixels while minimizing power consumption, particularly in active matrix organic light emitting diode (AMOLED) displays, as current dimming techniques often result in inefficient power usage due to the determination of off period ratios in units of one frame period.
Innovation Solution
The display device incorporates a controller that determines the off period ratio in units of two or more frame periods, adjusting the widths of off-level pulses of the emission start signal to minimize power consumption by extending the non-emission periods, and increases the cycle of emission clock signals to eight horizontal times, allowing for finer control over luminance levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the off period ratio is adjusted in units of one frame period, then the control granularity is coarse, but the power consumption cannot be sufficiently reduced
Solution Approach 1:
The patent divides the frame period into multiple sub-periods and introduces multiple off-level pulses within each frame period. By controlling the number, width, and positions of these off-level pulses, the system achieves fine-grained adjustment of the off period ratio, thereby precisely controlling power consumption without being limited to one-frame-period increments
Solution Approach 2:
The patent dynamically adjusts the widths of off-level pulses and the number of horizontal times based on dimming signals. This dynamic control allows the emission driver to adaptively optimize the off period ratio in real-time, achieving both fine adjustment precision and effective power consumption reduction
2Loss of energy
If the cycle of emission clock signals is increased to eight horizontal times, then the power consumption is reduced, but the control resolution may be affected
Solution Approach 1:
The patent employs periodic off-level pulses within the emission signal cycle. By strategically placing multiple off-level pulses at specific horizontal times within each clock cycle, the system maintains precise luminance control while operating with an extended eight-horizontal-time clock cycle, thus reducing power consumption without sacrificing control precision
Solution Approach 2:
The patent changes multiple parameters simultaneously including the cycle of emission clock signals (to eight horizontal times), the number of off-level pulses, their widths, and positions. This multi-parameter optimization allows the system to achieve both reduced power consumption and maintained control precision through coordinated parameter adjustment
3Measurement precision
If multiple off-level pulses are used in each frame period, then the off period ratio can be finely adjusted, but the signal complexity increases
Solution Approach 1:
The emission driver is designed with multi-functionality to handle various off-level pulse configurations. It can dynamically adjust the number, width, and positions of off-level pulses based on dimming requirements, achieving fine off period ratio adjustment while managing signal complexity through a unified control architecture
Data Source
AI summary
A display device includes a display panel including pixels connected to emission lines, a controller configured to receive a control signal, and to generate an emission start signal, a first emission clock signal and a second emission clock signal, and an emission driver configured to provide emission signals to the pixels through the emission lines in response to the emission start signal, the first emission clock signal and the second emission clock signal. The controller is further configured to determine an off period ratio for the pixels in units of two or more frame periods in response to the dimming signal. The control signal may be a dimming signal, a low power mode signal, or another type of signal indicative of operation of the display device.