OLED Display Power Supply Voltage Modulation for Luminance Control
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Solution Overview
Problem
Display devices, particularly OLEDs, face challenges in maintaining stable luminance due to errors in gamma setting, leading to differences between actual and intended luminance, and existing methods for adjusting luminance can result in grayscale inversion and high power consumption.
Innovation Solution
A display device with a power supply system that includes a first power supply unit for continuous voltage supply and a second power supply unit capable of cyclically adjusting the second power voltage based on intended luminance, using a signal controller to manage the power supply and prevent grayscale inversion while reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a driving circuit is used to adjust luminance by changing reference gamma voltage, then luminance adjustment is achieved, but power consumption increases and grayscale inversion may occur
Solution Approach 1:
The patent changes the control parameter from reference gamma voltage (electrical parameter) to power supply voltage (power parameter). By adjusting the power supply voltage to the OLED pixels, the luminance is controlled directly through power modulation rather than through complex driving circuit voltage adjustments, thereby reducing power consumption while avoiding grayscale inversion
Solution Approach 2:
The patent extracts the luminance control function from the driving circuit and relocates it to the power supply unit. This separation allows the driving circuit to focus on signal processing while the power supply unit handles luminance adjustment through voltage modulation, eliminating the power consumption and grayscale inversion issues associated with driving circuit-based control
2Manufacturing precision
If reference gamma voltage is programmed in real time to correct gamma setting errors, then display quality is improved, but device complexity increases
Solution Approach 1:
The power supply unit is designed to perform multiple functions: it not only supplies power to the display but also performs gamma correction and luminance control. By making the power supply unit multi-functional, the patent eliminates the need for separate circuits dedicated to gamma adjustment, thereby reducing device complexity while maintaining display quality
Solution Approach 2:
The patent simplifies gamma correction by changing the approach from adjusting reference gamma voltage through complex driving circuits to directly modulating power supply voltage. This parameter change transforms a complex multi-circuit adjustment problem into a simple single-parameter control problem, reducing device complexity while achieving the same gamma correction effect
3Use of energy by moving object
If power supply is used to adjust luminance instead of driving circuit, then power consumption is reduced, but control precision may be affected
Solution Approach 1:
The patent implements dynamic power supply voltage adjustment where the power supply unit can continuously modulate voltage levels in response to control signals. This dynamic capability ensures that even though power supply is used instead of driving circuits, the control precision is maintained through real-time voltage adjustment, allowing for fine-grained luminance control without sacrificing precision
Solution Approach 2:
The system incorporates feedback mechanisms where the signal controller monitors display output and adjusts power supply voltage accordingly. This feedback loop ensures that power consumption is reduced while maintaining control precision by making real-time adjustments to compensate for any potential precision loss from using power supply-based control
Data Source
AI summary
In an embodiment of the present invention, a display device includes a display unit including a plurality of pixels, a first power supply unit configured to supply a first power voltage to the display unit, and a second power supply unit configured to cyclically supply a second power voltage to the display unit during a frame period.