Pixel Voltage Regulating Circuit for Faster OLED Luminance Response
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Solution Overview
Problem
Organic light-emitting display devices experience slow response speed and luminance decay, leading to flicker phenomena and impaired image quality, especially during rapid changes in image scenes.
Innovation Solution
A power circuit comprising a DC-DC converter, digital-to-analog converter, and a voltage regulating circuit that adjusts voltages in units of one horizontal period to prevent gate-source voltage fluctuations, thereby improving pixel response characteristics and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If power is initially supplied to the display device, then the pixels can operate and display images, but the luminance cannot reach target luminance within one frame period and response speed is slow
Solution Approach 1:
The voltage regulating circuit performs preliminary action by adjusting the power supply voltage in advance during the horizontal period before the pixel needs to respond. By proactively regulating the voltage based on incoming pixel data, the circuit ensures that sufficient voltage is available when the pixel switching occurs, enabling faster response without extending the overall frame period.
Solution Approach 2:
The voltage regulating circuit implements dynamics by continuously adjusting the power supply voltage level in real-time based on the required pixel luminance. Instead of using a fixed voltage, the circuit dynamically modifies the voltage during the horizontal period to match the instantaneous display requirements, thereby optimizing pixel response speed adaptively.
2Adaptability or versatility
If the amount of transition or grayscale change in pixel data increases, then more image detail can be displayed, but the response speed becomes slower
Solution Approach 1:
The voltage regulating circuit adapts dynamically to different grayscale transition requirements by adjusting the voltage level according to the specific pixel data being displayed. When large grayscale changes are detected, the circuit provides higher voltage to accelerate pixel response, while maintaining optimal voltage for smaller transitions, thus preserving both adaptability and speed.
Solution Approach 2:
The circuit changes the voltage parameter in response to varying grayscale transition demands. By monitoring the pixel data and adjusting the power supply voltage accordingly, the system optimizes the electrical conditions for each specific display scenario, enabling fast response across the full range of grayscale transitions without compromise.
3Loss of energy
If the luminance of the pixel changes gradually within a light emission period, then power consumption can be reduced, but luminance decay occurs and image quality is impaired
Solution Approach 1:
The voltage regulating circuit implements feedback by continuously monitoring the pixel operation state and adjusting the power supply voltage to compensate for luminance decay. This closed-loop control ensures that the voltage is optimized to maintain consistent luminance output throughout the light emission period, preventing image quality degradation while managing power consumption efficiently.
4Measurement precision
If a DC-DC converter and digital-to-analog converter are used to generate pixel driving voltages, then voltage control precision is improved, but the voltage slope remains too steep causing luminance decay
Solution Approach 1:
The voltage regulating circuit introduces dynamics by actively adjusting the voltage output slope in real-time. Instead of using a fixed steep slope from the DAC, the regulating circuit modifies the voltage transition characteristics adaptively, softening the slope when necessary to prevent luminance decay while maintaining the precision benefits of digital-to-analog conversion.
Solution Approach 2:
The circuit changes the voltage slope parameter dynamically based on display conditions. By adjusting this temporal characteristic of the voltage signal, the system maintains the precision of DAC-generated voltages while eliminating the harmful effect of overly steep transitions that cause luminance decay and image quality issues.
Data Source
AI summary
A power circuit can include a direct current to direct current converter configured to output a first voltage; a digital-to-analog converter configured to convert input data to an analog voltage and output a second voltage; and a voltage regulating circuit configured to receive the first voltage and the second voltage as inputs and output a voltage in which the second voltage is added to the first voltage, and reduce a slope of the voltage. Also, the input data to the digital-to-analog converter is updated during one horizontal period of a display device, and the voltage regulating circuit is further configured to commonly supply the voltage to pixels of the display device.