Liquid Crystal Display Pixel Circuit with Dual Memory Capacitors
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Solution Overview
Problem
Liquid crystal display devices face challenges in reducing power consumption and achieving high image quality, particularly in increasing the number of grayscale levels beyond what can be output by the source driver and performing inversion driving while data is stored in pixels.
Innovation Solution
A liquid crystal display device incorporating a pixel with a first and second memory circuit, each containing a capacitor and a transistor, allowing for the storage of charges corresponding to different signals, enabling the application of a voltage to the liquid crystal element and performing inversion driving even when data is stored in the pixel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels is increased to improve resolution, then the display quality is improved, but the power consumption of the driver IC increases
Solution Approach 1:
The pixel circuit is segmented into multiple functional blocks: first and second memory circuits for storing different signal charges, transistors for charge transfer control, and a liquid crystal element. This segmentation allows the driver IC to operate at lower voltage amplitudes while maintaining the ability to drive high-resolution displays by distributing the driving function across multiple pixel-level components.
2Use of energy by moving object
If the voltage amplitude of the driver IC is reduced to lower power consumption, then the power consumption is reduced, but the number of grayscale levels that can be displayed is limited
Solution Approach 1:
The patent transitions from a single-dimension voltage control approach to a two-dimension charge storage approach. By using first and second memory circuits to store different signal charges that are subsequently combined, the system achieves higher grayscale precision (10 bits or more) while the driver IC operates at lower voltage amplitudes (8 bits). This dimensional transformation allows grayscale precision to be decoupled from driver voltage amplitude.
3Use of energy by moving object
If data is stored in the pixel to reduce power consumption, then the power consumption is reduced, but inversion driving cannot be performed
Solution Approach 1:
The patent implements a dynamic charge transfer mechanism where stored charges in the first and second memory circuits are selectively transferred to the liquid crystal element through controlled transistor switching. This dynamic operation allows the pixel to alternate between data storage mode (for power saving) and charge transfer mode (for inversion driving), enabling both functions to coexist through time-multiplexed operation.
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 allows for the display of a higher number of grayscale levels than the source driver can output and enables inversion driving while reducing power consumption by storing data in pixels, thereby enhancing image quality and reducing degradation of the liquid crystal element.
Implementation Method 1
The first memory circuit includes a first capacitor, and one electrode of the first capacitor is electrically connected to one electrode of the liquid crystal element. The second memory circuit includes a second capacitor, and one electrode of the second capacitor is electrically connected to the one electrode of the liquid crystal element.
Data Source
AI summary
A liquid crystal display device including a pixel containing a first memory circuit, a second memory circuit, and a liquid crystal element is provided. The first memory circuit includes a first capacitor. One electrode of the first capacitor is electrically connected to one electrode of the liquid crystal element. The second memory circuit includes a second capacitor. One electrode of the second capacitor is electrically connected to the one electrode of the liquid crystal element. The first memory circuit has a function of storing a charge corresponding to a first signal. The second memory circuit has a function of storing a charge corresponding to a second signal. A voltage is applied to the liquid crystal element by supplying a third signal to the other electrode of the first capacitor and supplying a fourth signal to the other electrode of the second capacitor, whereby an image is displayed.