Pixel Circuitry Voltage Following Module for Charge Sharing
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Solution Overview
Problem
Traditional pixel circuitries in flat panel displays experience charge sharing among coupled capacitors, leading to voltage reductions and image data transmission inaccuracies, resulting in gray level departures or distortions during image display.
Innovation Solution
Incorporation of a voltage following module with an active element, such as an operational amplifier or source follower, to detect and generate an output voltage that faithfully transmits the image data voltage to the display element, reducing the impact of charge sharing and maintaining the voltage level equal to the input data voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional passive elements (capacitors, switches) are used in pixel circuitry, then device complexity is reduced and ease of manufacture is improved, but charge sharing occurs among coupled capacitors causing voltage reduction and gray level distortion
Solution Approach 1:
The patent introduces a voltage follower circuit as an intermediary component between the data line and the display element. This voltage follower acts as a buffer that isolates the coupled capacitors in the pixel circuitry from affecting the data voltage, thereby preventing charge sharing from causing gray level distortion while maintaining the simplicity of passive element-based circuitry
Solution Approach 2:
The patent replaces the traditional passive element-only approach with an active element (voltage follower) to substitute the mechanical/physical charge sharing problem. The voltage follower uses active electronic components to actively maintain voltage levels rather than relying on passive capacitor isolation, thereby solving the gray level accuracy issue
2Quantity of substance
If coupled capacitors are used in pixel circuitry, then charge storage capacity is improved, but charge sharing occurs leading to voltage reduction and image data transmission inaccuracy
Solution Approach 1:
The voltage follower serves as an intermediary that decouples the charge storage function of the capacitors from the data voltage transmission path. It allows the capacitors to store charge while preventing this stored charge from sharing with and distorting the incoming data voltage, thereby maintaining both charge storage capacity and transmission accuracy
Solution Approach 2:
The patent segments the pixel circuitry into distinct functional zones: the data input path, the voltage follower buffer zone, and the display element drive zone. This segmentation isolates the charge sharing problem to specific capacitor elements while protecting the critical data voltage transmission path through the voltage follower boundary
3Measurement precision
If voltage follower module is added to pixel circuitry, then image data voltage transmission accuracy is improved, but device complexity increases
Solution Approach 1:
The voltage follower is introduced as a minimal intermediary component that provides maximum benefit with minimal added complexity. It is a single-stage buffer circuit that can be implemented with a simple operational amplifier or transistor configuration, adding only one functional block to the pixel circuitry while effectively solving the voltage accuracy problem
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
The solution effectively reduces voltage differences caused by charge sharing, ensuring accurate transmission of image data voltage to the display element, thereby minimizing gray level departures and distortions, and maintaining the voltage level close to the intended data voltage level.
Implementation Method 1
The first voltage following module has an input terminal coupled to the first write memory unit to detect the first data voltage stored in the first write memory unit and to generate a first output voltage correspondingly at an output terminal of the first voltage following module according to a detection result
Implementation Method 2
The first voltage follower includes a source follower. The source follower includes a first transistor and a second transistor. The first transistor has a control terminal which serves as an input terminal of the source follower
Data Source
AI summary
A pixel circuitry of a display device is provided to make a voltage level transmitted to a display element be close to a voltage level of a received data voltage, such that the pixel circuitry faithfully transmits the data voltage to the display element. The pixel circuitry of a display device includes a first write switch, a first write memory unit, a first voltage following module, and a display element. The first voltage following module is to detect a first data voltage stored in the first write memory unit, and to generate a corresponding first output voltage at a terminal of the display element based on a detection result. A first output terminal of the first voltage following module is controlled by a switching voltage.