Liquid Crystal Pixel Circuit for Blue Phase Display Voltage Boosting
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Solution Overview
Problem
Blue phase liquid crystal displays require a higher operating voltage due to insufficient transmittance caused by low data voltage in traditional liquid crystal pixel circuits, limiting their image quality and response time.
Innovation Solution
A liquid crystal pixel circuit design incorporating a first switch, a second switch, a storage capacitor, a liquid crystal capacitor, and a third and fourth switch, with specific gate signals and voltage configurations to enhance the operating voltage range through capacitive coupling and DC voltage adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional liquid crystal pixel circuit with low data voltage is used, then circuit complexity is reduced, but transmittance is insufficient and operating voltage range is limited
Solution Approach 1:
The pixel circuit is divided into multiple switching transistors (first switch, second switch, third switch, fourth switch) with distinct functions. Each switch controls specific voltage application to the liquid crystal capacitor, allowing independent optimization of voltage control without increasing overall circuit complexity significantly.
Solution Approach 2:
The circuit dynamically applies different voltages (common voltage, data voltage, set voltage) to the liquid crystal capacitor at different time periods through controlled switching. This dynamic voltage control enables the liquid crystal to achieve sufficient transmittance by applying higher operating voltages when needed, while maintaining circuit efficiency.
2Illumination intensity
If higher operating voltage is applied to blue phase liquid crystal, then transmittance is improved, but power consumption increases
Solution Approach 1:
The circuit applies high voltage periodically rather than continuously. During specific time periods, the third and fourth switches apply set voltage to boost the operating voltage for improved transmittance. During other periods, the circuit returns to normal operation with lower voltage, reducing overall power consumption while maintaining display quality.
Solution Approach 2:
The circuit changes the voltage parameter dynamically by applying different voltages (common voltage, data voltage, set voltage) at different time periods. This parameter modulation allows the liquid crystal to operate at higher voltage when transmittance is needed, then return to lower voltage states to reduce power consumption.
3Speed
If higher operating voltage is applied to blue phase liquid crystal, then response time is improved, but device reliability decreases
Solution Approach 1:
The circuit applies high voltage periodically during specific time periods to achieve fast response time when needed, then returns to normal operating voltage levels. This periodic high-voltage application provides the speed benefits for blue phase liquid crystal while limiting the duration of high-stress conditions, thereby maintaining device reliability.
Solution Approach 2:
The circuit dynamically adjusts the operating voltage based on timing requirements. By applying higher voltage (set voltage + data voltage) only during specific periods when fast response is needed, the circuit achieves improved response time while avoiding continuous high-voltage stress that would degrade device reliability.
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 increases the operating voltage range of the liquid crystal pixel circuit, improving transmittance and response time by adjusting the voltage difference between the set and data voltages, thereby enhancing the overall image quality.
Implementation Method 1
a storage capacitor and a liquid crystal capacitor coupled in parallel
Data Source
AI summary
A liquid crystal (LC) pixel circuit of a LC display panel includes a first, a second, a third and a fourth switches, a LC capacitor and a storage capacitor. A first and a control terminals of the first switch respectively receive a common voltage and a first gate signal. A first and a control terminals of the second switch respectively receive a data voltage and a second gate signal. The storage capacitor and the LC capacitor electrically connect between second terminals of the first and second switches. A first and a control terminals of the third switch respectively receive the common voltage and a third gate signal. A first and a control terminals of the fourth switch respectively receive a set voltage and a fourth gate signal. Second terminals of the third and the fourth switches respectively connect to the second terminals of the second and the first switches.