Dynamic Power Supply for Organic EL Displays
Solution Overview
Problem
Conventional organic electroluminescence (EL) display devices consume excessive power due to voltage drop in power source wires, particularly in large-sized displays, as the power drop margin for compensating voltage drop is not effectively reduced, leading to insufficient power consumption reduction.
Innovation Solution
A display device configuration that includes a power supplying unit regulating the high-side potential based on the potential difference between the low-side and cathode potentials measured, using a voltage measuring unit to feedback the cathode potential rise, allowing for appropriate voltage setting despite limited negative electrode supply potential, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the power source voltage is set with a voltage drop margin to compensate for wire resistance, then the display luminance is maintained across all pixels, but the power consumption increases unnecessarily for typical natural images
Solution Approach 1:
The power source voltage is made dynamic rather than fixed. The voltage supplying unit adjusts the power source voltage in real-time based on the actual luminance of the displayed image. When displaying typical natural images with lower peak luminance, the system reduces the power source voltage accordingly, eliminating the unnecessary voltage drop margin that would otherwise be required for all-white images. This dynamic adjustment resolves the contradiction by maintaining adequate luminance compensation only when needed.
Solution Approach 2:
The system implements a feedback mechanism where the actual luminance of the displayed image is detected and used to adjust the power source voltage. The voltage supplying unit receives information about the displayed content's luminance characteristics and automatically adjusts the power source voltage to match the actual requirements. This feedback loop enables the system to reduce power consumption for typical images while maintaining proper luminance compensation when displaying high-luminance content.
2Stability of the object's composition
If the power source voltage is increased to compensate for voltage drop in large-sized displays, then the luminance uniformity across the display is improved, but the power consumption increases significantly
Solution Approach 1:
The system dynamically adjusts the power source voltage based on the actual display requirements rather than using a fixed high voltage to compensate for wire resistance. By detecting the peak luminance of the displayed image and adjusting the power source voltage accordingly, the system maintains luminance uniformity across large displays only when necessary, while reducing power consumption during typical operation with natural images.
Solution Approach 2:
The power source voltage parameter is changed dynamically based on the displayed content characteristics. Instead of maintaining a consistently high voltage to compensate for wire resistance in large displays, the system adjusts the voltage parameter according to the actual luminance requirements of the displayed image, thereby maintaining luminance uniformity when needed while reducing power consumption during normal operation.
3Measurement precision
If the power source voltage is set high to ensure adequate current for all pixels, then the luminance accuracy is maintained, but unnecessary power is consumed when current demand is low
Solution Approach 1:
The power source voltage is adjusted dynamically to match the actual current demand of the display. By detecting the peak luminance of the displayed image and calculating the required current, the system sets the power source voltage to the minimum necessary level to achieve accurate luminance reproduction. This eliminates the waste of maintaining a consistently high voltage when lower current levels are sufficient for typical natural images.
Solution Approach 2:
The power source voltage parameter is optimized based on the actual luminance requirements. The system changes the voltage parameter from a fixed high value to a dynamically adjusted value that matches the current demand, thereby maintaining luminance accuracy when high current is needed while reducing unnecessary power consumption when lower current suffices for typical display content.
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
This configuration effectively addresses the variation in luminance between pixels and over time, achieving significant power consumption reduction while maintaining display quality, especially in large-sized displays.
Implementation Method 1
a voltage measuring unit configured to measure a cathode potential of the pixel
Implementation Method 2
the power supplying unit is configured to regulate the high-side potential with respect to the low-side potential, according to a potential difference between the low-side potential supplied to the display unit and the cathode potential measured by the voltage measuring unit
Data Source
AI summary
A display device includes an organic EL display unit including plural pixels, a variable-voltage source which supplies a positive electrode supply potential and a negative electrode supply potential to the display organic EL display unit, and an arithmetic circuit which measures an anode potential and a cathode potential of a representative pixel. The variable-voltage source regulates the positive electrode supply potential with respect to the negative electrode supply potential, according to at least the potential difference between the negative electrode supply potential of the variable-voltage source and the cathode potential of the representative pixel, and supply the regulated positive electrode supply potential to the organic EL display unit.