Source Driver Lookup Table for OCB LCD Signal Delay
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Solution Overview
Problem
Conventional LCD devices suffer from signal delay and limited frame frequency due to the slew rate limitations of their source drivers, which hinder the fast response speed benefits of OCB mode liquid crystal displays.
Innovation Solution
A new source driver design that includes a memory for storing gradation data in a lookup table format and a switching part to selectively apply pulse waveforms corresponding to various voltage levels, allowing for efficient display of gradations using few voltage levels, thereby reducing signal delay and enhancing response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional source driver with D/A converter and amp/buffer is used, then the LCD device can display images, but signal delay occurs and frame frequency is limited due to slew rate limitations
Solution Approach 1:
The patent extracts and removes the problematic D/A converter and amp/buffer components from the source driver. Instead of using these conventional components that introduce signal delay due to slew rate limitations, the invention directly applies digital gradient data to control the liquid crystal gradation, thereby eliminating the source of signal delay while maintaining display functionality.
2Productivity
If a conventional source driver with analog voltage output is used, then the LCD device can display gradations, but the response speed is limited by the slew rate of the amplifier
Solution Approach 1:
The patent substitutes the analog mechanical amplifier system with a digital control system. Instead of using an amp/buffer that requires analog voltage conversion and is limited by slew rate, the invention uses a digital source driver that directly outputs gradient data in digital form, replacing the analog signal path with a digital one that has no slew rate limitations, thereby enabling faster response and higher frame frequency.
3Measurement precision
If color filter layers are formed on separate substrates to achieve high resolution, then image quality improves, but manufacturing complexity increases and luminance is reduced
Solution Approach 1:
The patent merges the color filter layers onto a single substrate instead of using separate substrates for each color layer. This consolidation approach maintains the ability to achieve high resolution through the liquid crystal modulation while significantly reducing manufacturing complexity by eliminating the need to handle and align multiple separate substrates, and also improves luminance by reducing light loss from multiple filter interfaces.
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 reduces signal delay and increases response speed, allowing the OCB mode LCD device to exhibit its fast response capabilities, improving the display's overall performance by enabling faster gradation changes and reduced luminance variation.
Implementation Method 1
applying an electric field to liquid crystals having an anisotropic dielectric constant placed (i.e., injected) between two substrates and controlling electric field intensity, thereby controlling an amount of light transmitted onto the substrates
Implementation Method 2
controlling an amount of light transmitted onto the substrates from an external light source (backlight)
Implementation Method 3
a liquid crystal display device includes an LCD panel including a plurality of pixels which are formed on a region where a plurality of scan lines and a plurality of data lines cross each other so that a screen image is displayed
Data Source
AI summary
The present invention relates to a liquid crystal display device with a source driver in which a signal without a significant delay is generated, which has a fast response speed and provides a liquid crystal display device having a scan driver comprising a memory in which gradation data values are stored in a lookup table and which sequentially outputs a plurality of switching signals corresponding to the gradation data inputted The device also includes a switching part to which the plurality of switching signals are applied to sequentially select a plurality of voltage levels so that a plurality of pulse waveforms corresponding to the selected plurality of voltage levels are sequentially applied to the respective pixels including liquid crystal cells during one frame, wherein the liquid crystal display further includes a voltage generation part for producing the plurality of voltage levels, the memory outputs a switching signal for resetting the liquid crystal cells in the early stage of each frame, and the liquid crystal cells are OCB liquid crystal cells.