Liquid Crystal Display Driver Circuit with EEPROM Data Protection
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Solution Overview
Problem
Conventional liquid crystal display devices face challenges in improving response speed and maintaining high image quality due to reduced response speed of liquid crystal molecules, leading to vague latent images, and also suffer from unreliable external storage units like EEPROMs that are prone to undesired data writing and loss, affecting display reliability and brightness control.
Innovation Solution
A circuit for driving liquid crystal displays that includes a master for over-driving and adaptive brightness intensification, a slave for providing control data, and a writing circuit that controls data writing to the slave, with an internal power supply ensuring the write control terminal is at ground potential in write mode and internal power supply potential in drive mode, preventing undesired data writing and enhancing data protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the gray scale voltage is changed to express moving images, then the image quality is improved, but the response speed of liquid crystal molecules is reduced due to dielectric anisotropy and permittivity variation
Solution Approach 1:
The patent applies over-driving by applying a voltage higher than the normal gray scale voltage to the liquid crystal molecules in advance. This preliminary action with excessive voltage compensates for the slow response caused by dielectric anisotropy, enabling the liquid crystal to reach the desired state within the frame period and prevent latent image overlap.
2Device complexity
If an external storage unit like EEPROM is used to store control data, then the device complexity is reduced, but the reliability is worsened due to undesired data writing and data loss
Solution Approach 1:
The patent introduces a write control terminal as an intermediary control mechanism between the external storage unit and the writing circuit. This terminal acts as a gatekeeper that prevents undesired writing operations, thereby protecting the integrity of control data stored in the EEPROM while maintaining the simplicity of using an external storage unit.
3Ease of operation
If the write control terminal is not properly controlled, then the ease of operation is improved, but the reliability is worsened due to undesired data writing during liquid crystal module drive mode
Solution Approach 1:
The patent implements a feedback mechanism where the write control terminal monitors the operational mode of the system. When the liquid crystal module drive mode is detected, the feedback signal automatically disables the writing function, preventing undesired data writing while maintaining simple operation during normal modes.
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 enhances the response speed of liquid crystal molecules, improves image quality by preventing data loss and ensuring reliable display, and extends the service life of backlight lamps by controlling brightness adaptively, thus addressing the limitations of conventional systems.
Implementation Method 1
an internal power supply of a liquid crystal module for applying an internal supply voltage to the slave, wherein the write mode does not occur during the liquid crystal module drive mode
Implementation Method 2
a master for over-driving a liquid crystal module and provides adaptive brightness intensification
Implementation Method 3
a master for over-driving a liquid crystal module and provides adaptive brightness intensification
Data Source
AI summary
A circuit that drives a liquid crystal display device, includes an EEPROM having control data that over-drives and provides adaptive brightness intensification, the control data in the EEPROM is protected so as to secure reliability of the EEPROM. The circuit includes a master for over-driving and adaptive brightness intensification, a slave for providing control data to the master, a connector for connecting external writing equipment with terminals on the slave to write the control data into the slave, and an internal power supply of a liquid crystal module that applies an internal supply voltage to the slave. A write control terminal on the slave is grounded in a write mode, and connected to the internal power supply of the liquid crystal module in a liquid crystal module drive mode.