Variable-Voltage Source for Organic EL Display Power Management
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Solution Overview
Problem
Conventional organic electroluminescence (EL) display devices consume excessive power due to the need to account for peak power consumption when designing power source circuits, leading to inefficiencies in power management, especially in large-sized displays where voltage drops in power source wires become significant, resulting in inadequate power savings.
Innovation Solution
A display device with a variable-voltage source that monitors and regulates the potential difference between high-side and low-side potentials applied to pixels, using a monitor wire to detect voltage drops and adjust the output voltage accordingly, reducing unnecessary power consumption by optimizing voltage margins based on detected voltage differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If power source voltage is set with a large voltage drop margin to compensate for wire resistance, then display luminance uniformity is improved, but power consumption increases
Solution Approach 1:
The power source voltage is made dynamically adjustable based on detected voltage drops. The voltage supply is changed from a fixed high margin value to a variable value that adapts to actual operating conditions, allowing optimization between luminance uniformity and power consumption
Solution Approach 2:
A detection circuit measures the actual voltage drop in the power source wire and feeds this information back to the power source. This feedback loop enables automatic adjustment of the supply voltage to maintain optimal luminance uniformity while minimizing unnecessary power consumption
2Reliability
If voltage supply is increased to compensate for voltage drops in large panels, then display performance is improved, but power consumption increases significantly
Solution Approach 1:
The power source voltage parameter is changed from a fixed high value to a variable value based on actual voltage drop measurements. This allows the system to maintain display performance when needed while reducing voltage (and power consumption) when voltage drops are minimal
3Use of energy by moving object
If power source voltage is regulated to reduce power consumption, then power efficiency is improved, but display luminance may drop
Solution Approach 1:
The detection circuit monitors voltage drops and provides feedback to maintain luminance. By detecting actual voltage conditions, the system can regulate power consumption while ensuring luminance remains adequate through dynamic voltage adjustment
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 approach effectively reduces power consumption by minimizing voltage drops in power source wires, enhancing the efficiency of organic EL display devices, particularly in large-sized displays, while preventing luminance drops and heat generation that can lead to organic EL element deterioration.
Implementation Method 1
the luminance of an organic electroluminescence (EL) element is dependent upon the drive current supplied to the element
Implementation Method 2
current flows through a power source wire and a voltage drop which is proportionate to the wire resistance occurs
Data Source
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AI summary
A display device (300) according to the present invention includes: a high-side potential variable-voltage source (180A) which outputs a high-side output potential and a low-side potential variable-voltage source (180B) which outputs a low-side output potential; an organic EL display unit (310) in which pixels are arranged; a high-side potential difference detecting circuit (170A) which detects a high-side potential applied to a pixel (111MA) and a low-side potential difference detecting circuit (170B) which detects a low-side potential applied to a pixel (111MB); a high-side potential voltage margin setting unit (175A) and a low-side potential voltage setting unit (175B) which regulate the output potential of the high-side potential variable-voltage source (180A) and the low-side potential variable-voltage source (180B) to set a potential difference between the high-side potential of the pixel (111MA) and a reference potential to a predetermined potential difference and set a potential difference between the low-side potential of the pixel (111MB) and a reference potential to a predetermined potential difference; and a signal processing circuit (165).