Gamma Voltage Generator for OLED Low Gray Scale Luminance Accuracy
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Solution Overview
Problem
Existing gamma voltage generators face challenges in accurately generating grayscale voltages for low gray scales, leading to increased power consumption and differences between target and actual luminance, as it is difficult to measure luminance in low gray scale conditions.
Innovation Solution
A gamma voltage generator that includes a gamma reference voltage selector, a medium gamma voltage selector, and a medium gamma voltage calculator, which calculates low gamma voltages using the equation V=5.481-(L*6.1)1/2, where V is the low gamma voltage and L is the luminance value, to accurately produce voltages for low gray scales, and a grayscale voltage generator that voltage-divides medium gamma voltages to generate grayscale voltages for an OLED display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional gamma voltage generation methods are used, then the device structure remains simple, but luminance accuracy deteriorates in low gray scales
Solution Approach 1:
The gamma voltage generator is divided into multiple functional modules: a gamma reference voltage selector that selects from multiple gamma reference voltages, a medium gamma voltage selector that generates medium gray scale voltages, and a low gamma voltage calculator that specifically calculates low gray scale voltages using the gamma characteristic equation. This segmentation allows each module to be optimized for its specific function, improving luminance accuracy in low gray scales while maintaining manageable device complexity through modular design.
Solution Approach 2:
The system pre-calculates and stores multiple gamma reference voltages corresponding to different gray scales before actual display operation. The low gamma voltage calculator uses pre-established gamma characteristic equations to compute accurate low gray scale voltages, avoiding the need for real-time measurement and adjustment during operation. This preliminary preparation ensures high luminance accuracy when needed without adding complex real-time measurement systems.
2Measurement precision
If conventional gamma voltage generation is used, then power consumption may be lower with simpler circuits, but luminance measurement and control become inaccurate
Solution Approach 1:
The patent introduces a gamma characteristic equation as an intermediary mathematical model that relates voltage to luminance without requiring direct physical measurement. The equation V=5.481-(L*6.1)1/2 serves as a mediator that allows the system to calculate accurate luminance values and corresponding voltages theoretically, eliminating the need for complex real-time luminance measurement hardware and reducing power consumption while maintaining high measurement precision.
3Manufacturing precision
If low gray scale voltages are not accurately generated, then device complexity remains low, but power consumption increases and luminance accuracy decreases
Solution Approach 1:
The system dynamically adjusts voltage parameters based on the required gray scale level. For low gray scales, it uses specifically calculated low gamma voltages derived from the gamma characteristic equation, while for medium and high gray scales, it uses voltages from the medium gamma voltage selector. This parameter optimization ensures that each gray scale range operates with the most appropriate voltage levels, minimizing power consumption while maintaining accurate luminance control across all gray scales.
Data Source
AI summary
A gamma voltage generator, method of generating gamma voltage, and an OLED display including the generator are disclosed. In one aspect, the generator includes a gamma reference voltage selector configured to receive a gamma reference voltage from a voltage generator and output selected first to third gamma voltages having values substantially equal to or less than the gamma reference voltage. The generator also includes a medium gamma voltage selector configured to receive the first to third gamma voltages from the gamma reference voltage selector and select and output a plurality of medium gamma voltages based at least in part on the first to third gamma voltages. The generator further includes a medium gamma voltage calculator configured to output a selection signal corresponding to the calculated low gamma voltage to the medium gamma voltage selector.