AMOLED Pixel Brightness Control via Biasing Voltage
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Solution Overview
Problem
Active Matrix Organic Light Emitting Diode (AMOLED) displays face increased complexity and cost in brightness control due to the need for image frame data analysis and specialized circuitry to adjust pixel brightness, which complicates energy-efficient brightness control mechanisms.
Innovation Solution
Implementing a biasing signal, such as a biasing voltage, that is applied to all pixels to reduce brightness proportionally, eliminating the need for image processing and simplifying circuitry by allowing pixel-by-pixel brightness adjustment without analyzing image data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If image frame data analysis and specialized circuitry are used to adjust pixel brightness in AMOLED displays, then brightness control capability is improved, but circuit complexity and cost increase
Solution Approach 1:
The patent changes the operating parameters of existing pixel circuits by applying a biasing voltage to the emission switch. This biasing voltage modulates the current flowing through the OLED element, thereby controlling brightness without requiring additional specialized circuitry or image frame data analysis. The existing circuit components are utilized with modified voltage parameters to achieve brightness control.
Solution Approach 2:
The biasing signal applied to the emission switch serves multiple functions simultaneously: it controls the timing of light emission, regulates the current through the OLED element, and adjusts brightness levels. This multi-functional approach eliminates the need for separate specialized brightness control circuitry, as the existing emission switch and biasing infrastructure are used for both timing and brightness regulation.
2Measurement precision
If image processing is performed to determine brightness reduction, then brightness control accuracy is improved, but power consumption increases
Solution Approach 1:
The system uses the existing biasing infrastructure and pixel circuit components to perform brightness control without requiring separate image processing units or additional power-consuming analysis circuits. The emission switch and biasing signal work together to automatically regulate brightness based on the programmed emission timing, making the system self-sufficient for brightness control.
Solution Approach 2:
Brightness control is achieved by modifying the voltage parameter of the biasing signal applied to the emission switch, rather than through complex image processing. This parameter-based control method maintains brightness accuracy while significantly reducing power consumption compared to active image analysis circuits.
3Use of energy by moving object
If emission time is shortened to reduce brightness, then power consumption is reduced, but brightness control flexibility is limited
Solution Approach 1:
The patent implements dynamic brightness control by applying a time-varying biasing voltage to the emission switch during the emission period. This allows the brightness to be adjusted continuously throughout the emission time, enabling both power reduction through shortened emission and flexible brightness control through voltage modulation. The system can adapt brightness levels dynamically without being constrained to fixed emission time reductions.
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 reduces circuit complexity, power consumption, and heat generation while maintaining effective brightness reduction capabilities, making it suitable for various display types and applications.
Implementation Method 1
These individual pixels emit light with intensity according to a value programed into that pixel, which causes a proportional electrical current to be supplied to the in-pixel OLED device
Implementation Method 2
Lowering the voltage between EL_VDD and EL_VSS causes a reduction in the voltage across the OLED pixel and thereby reduces the electrical current passing through the pixel
Data Source
AI summary
A multiple pixel display and method of driving same. Each pixel in the display has a light emitting element and a drive current controller. A control terminal of the drive current controller receives an intensity control input and drives the light emitting element with an amount of electrical current based upon the intensity control input. Each pixel also has a voltage storage device that is charged with a programmed voltage between with a first terminal that is electrically coupled to the control terminal, and a second terminal that is electrically opposite the first terminal of the voltage storage device. An intensity reduction input of each pixel is electrically coupled to the second terminal of the voltage storage device and to respective intensity reduction inputs of other pixels within the plurality of pixels.