Liquid Crystal Display Drive Circuit Scale Reduction
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Solution Overview
Problem
Existing liquid crystal display devices face challenges in reducing the circuit scale of their drive circuits, particularly when dealing with the increasing display area relative to the liquid crystal panel, which affects the longevity and image quality due to polarity deviations in voltage applications.
Innovation Solution
The liquid crystal display device incorporates a drive circuit with pixel electrodes, a common electrode, pixel transistors, data signal lines, equalizing transistors, and a shift register that includes a damper transistor to manage voltage polarity reversals and reduce circuit complexity, allowing for efficient grayscale voltage application and signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the drive circuit is simplified to reduce circuit scale, then the circuit complexity is reduced, but the ability to manage voltage polarity reversals and maintain signal stability deteriorates
Solution Approach 1:
The patent extracts the polarity management function from the main drive circuit by introducing a separate damper transistor. This allows the main circuit to remain simple while the extracted damper component handles the complex polarity reversal tasks, resolving the contradiction between circuit simplicity and reliability.
Solution Approach 2:
The damper transistor acts as an intermediary element between the signal line and ground, providing a controlled path for voltage discharge during polarity reversals. This intermediary component enables stable signal transmission without requiring complex circuitry, thus maintaining reliability while keeping the overall circuit scale reduced.
2Stability of the object's composition
If the equalizing transistor operates at every polarity reversal cycle, then the voltage balance is maintained, but the operational complexity and energy consumption increase
Solution Approach 1:
The equalizing transistor operates periodically at polarity reversal cycles rather than continuously, maintaining voltage balance only when needed. This periodic operation reduces energy consumption compared to continuous operation while still ensuring voltage stability during critical transition moments.
Solution Approach 2:
The damper transistor provides automatic voltage discharge functionality that operates autonomously during polarity reversals, reducing the need for active control of the equalizing transistor. This self-service mechanism maintains voltage balance with minimal energy input.
3Area of moving object
If the display area is increased relative to the liquid crystal panel, then the picture frame is narrowed and display efficiency improves, but the circuit scale reduction becomes more difficult
Solution Approach 1:
The patent merges the drive circuit and display panel into an integrated structure where the common electrode is formed on the same substrate as the pixel electrodes. This integration eliminates separate circuit boards and connection components, enabling circuit scale reduction that accommodates larger display areas with narrower picture frames.
Solution Approach 2:
The patent transitions from a planar circuit layout to a three-dimensional integrated structure by forming electrodes and circuits on stacked substrates. This dimensional change allows circuit components to occupy vertical space rather than horizontal space, enabling display area expansion without proportionally increasing circuit scale.
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 configuration reduces the circuit scale, enhances image quality by minimizing voltage polarity shifts, and decreases electrical load and noise in signal lines, while maintaining stable signal transmission and high dielectric strength.
Implementation Method 1
a liquid crystal display device which controls an image to be displayed by changing the degree of transmissivity of light by controlling the alignment of liquid crystal composition sealed between a thin film transistor substrate
Implementation Method 2
it is necessary to change an electric field between the substrates by controlling voltages applied to electrodes provided to the substrates
Data Source
AI summary
A liquid crystal display device which can reduce a circuit scale of a drive circuit is provided. A TFT substrate of the liquid crystal display device includes a pixel circuit in each pixel, and the pixel circuit includes a thin film transistor, a pixel electrode which is connected to a source side of the thin film transistor, and a common electrode which is one planar transparent electrode extending in a display region in a planar shape. A vertical drive circuit includes a transistor which is driven by a control signal voltage including a clock signal from a drive IC, and constitutes a damper for a high voltage. The drive IC outputs an equalizing switch signal voltage to equalizing switches which connect the common electrode and data signal lines.