Cholesteric Liquid Crystal Display Driving Method for Temperature Compensation
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Solution Overview
Problem
Cholesteric liquid crystal display elements face challenges in maintaining optimal grayscale display at varying temperatures, requiring adjustments in voltage application conditions, which increases manufacturing costs due to the need for high-speed transmission drivers and receivers.
Innovation Solution
A method of driving liquid crystal display elements by applying an alternating current (AC) pulse voltage with a shorter pulse width at higher temperatures, maintaining the same pulse width modulation conditions as at room temperature to compensate for temperature variations without increasing processor load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pulse width modulation method is used to compensate for temperature variations, then the display performance at high temperature is improved, but the processor load increases and requires high-speed transmission drivers and receivers
Solution Approach 1:
The patent changes the pulse width parameter of the AC voltage applied to the liquid crystal based on temperature. At high temperatures, a shorter pulse width is used to compensate for the increased response speed of the liquid crystal, maintaining optimal display performance without requiring high-speed transmission drivers and receivers
2Manufacturing precision
If the voltage application conditions are adjusted according to temperature variation, then the grayscale display is optimized, but the manufacturing cost increases
Solution Approach 1:
The patent adjusts the pulse width parameter of the driving voltage based on temperature conditions. By using a shorter pulse width at high temperatures, the system maintains optimal grayscale display performance while avoiding the need for expensive high-speed transmission drivers and receivers, thereby reducing manufacturing costs
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 approach allows for optimal display performance at high temperatures with the same processor transmission rate as at room temperature, eliminating the need for high-speed transmission drivers and multiple power supply circuits, thus reducing manufacturing costs.
Implementation Method 1
a reflective display element using a cholesteric-phase liquid crystal composition (hereinafter, referred to as cholesteric liquid crystal) has been used for the electronic paper
Implementation Method 2
the spiral pitch of the liquid crystal molecules is substantially equal to a wavelength of circularly polarized light
Implementation Method 3
When voltage application conditions (the voltage value and the pulse width of a pulse voltage) that have been set to perform optimum grayscale display at room temperature are applied to a display process at high temperature
Data Source
AI summary
A method of driving a liquid crystal display element that applies an AC pulse voltage to drive liquid crystal includes: when the temperature of the liquid crystal is higher than a reference temperature, generating the AC pulse voltage for high temperature having a pulse width that is shorter than a reference pulse width of a reference AC pulse voltage used at the reference temperature; and applying the generated AC pulse voltage to the liquid crystal in a period that is equal to the reference pulse width.