Cholesteric Liquid Crystal Display Inrush Current Reduction
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Solution Overview
Problem
Cholesteric liquid crystal display devices experience excessive inrush current and high power supply loads due to high positive and negative voltage reset signals, leading to increased manufacturing costs for driver ICs.
Innovation Solution
A cholesteric liquid crystal display device with a timing control driver and liquid crystal driving unit that outputs enable signals at different timings to apply reset voltages to pixel matrices, avoiding voltage overlap and reducing inrush current by time-shifting data latch enable signals for each color matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If driver ICs apply reset signals with high positive and negative level of voltages to pixel matrix at the same time, then the screen can be cleared quickly, but voltage build-up in liquid crystal molecules causes excessive inrush current and large power supply load
Solution Approach 1:
The patent segments the simultaneous reset operation into sequential operations by dividing pixel matrices into multiple groups (first group and second group). The driver IC applies reset signals to different groups at different times, preventing voltage build-up and reducing inrush current while still achieving complete screen clearing.
Solution Approach 2:
The patent applies preliminary control by using a timing control driver to预先 determine and separate the timing of reset signal application to different pixel matrix groups. This preliminary timing arrangement prevents the simultaneous voltage application that causes inrush current, while ensuring all pixels are eventually reset.
2Productivity
If driver ICs apply reset signals with high positive and negative level of voltages to pixel matrix at the same time, then the screen can be cleared quickly, but the cost of driver ICs increases
Solution Approach 1:
The patent segments the pixel matrices into multiple groups that are reset sequentially rather than simultaneously. This reduces the peak current handling requirements for the driver IC, allowing for the use of lower-cost driver components that cannot handle the high simultaneous current loads required for parallel reset of all pixels.
Solution Approach 2:
The patent implements periodic action by applying reset signals to different pixel matrix groups at different time periods. This temporal separation reduces the instantaneous power requirements, enabling the use of more cost-effective driver IC designs with lower current capabilities.
3Device complexity
If enable signals are outputted at the same time to all pixel matrices, then the control process is simple, but voltage build-up causes excessive inrush current
Solution Approach 1:
The patent segments the control process by dividing pixel matrices into multiple groups with different enable signal timing. While this adds some control complexity, it effectively prevents voltage build-up and inrush current by ensuring that not all pixel matrices receive reset voltages simultaneously, thus reducing peak power consumption.
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 reduces inrush current and alleviates power supply burdens, lowering manufacturing costs by optimizing the voltage application process for the cholesteric liquid crystal display device.
Implementation Method 1
the liquid crystal driving unit increases a voltage based on the data latch enable signal so that the orientation of the liquid crystal molecules of the cholesteric liquid crystal display panel is in Homeotropic State. While the voltage is lowered, the orientation of the liquid crystal molecules is transitioned to Planar State
Data Source
AI summary
A cholesteric liquid crystal display device and a control method for reducing inrush current when clearing the screen. The cholesteric liquid crystal display device includes a cholesteric liquid crystal display panel and a liquid crystal drive unit. The cholesteric liquid crystal display panel has a plurality of pixel matrix. After the liquid crystal drive unit receives a data latch enable signal, it applies a reset voltage to the plurality of pixel matrix to clear the screen displayed on the cholesteric liquid crystal display panel. The input time of the data latch enable signal received by the liquid crystal driving unit is different, and the corresponding signal time portion is shifted with each other.