Display Controller Parameter Initialization for Reliable Power-Off
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Solution Overview
Problem
Existing liquid crystal display technologies face issues with accepting command inputs during the power-off sequence process, leading to incomplete parameter changes and potential degradation due to residual electric charge, as commands are not reflected during the power-off sequence, and initial parameters may not be optimal for all electronic devices.
Innovation Solution
A controller that initializes parameter values before the power-off sequence, allowing command inputs to be reflected during the process, and applies turn-off voltage with opposite polarity to ensure complete discharge and optimal driving conditions, even if vertical scanning is interrupted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If parameter initialization is performed after the power-off-sequence process, then display halting is completed, but commands input during the power-off-sequence process cannot be reflected
Solution Approach 1:
The parameter initialization is performed preliminarily before the power-off-sequence process starts. When a reset signal is input, the parameter initialization unit initializes the parameters immediately, and only after initialization completes does the control unit execute the power-off-sequence process. This preliminary action ensures that any commands input during the power-off-sequence process will be reflected in the already-initialized parameters.
2Reliability
If turn-off voltage is applied to discharge pixel electric charge, then liquid crystal characteristic degradation is suppressed, but display interruption may occur due to sporadic incidents
Solution Approach 1:
The parameter initialization is performed preliminarily before the power-off-sequence process that applies turn-off voltage to discharge pixel charge. This sequencing ensures that parameter changes are already in effect before the voltage application, reducing the risk of display interruptions caused by parameter changes during voltage discharge.
3Reliability
If the power-off-sequence process is executed first, then electric charge is discharged before halting display, but parameter changes cannot be accepted during the process
Solution Approach 1:
The parameter initialization is performed as a preliminary action before the power-off-sequence process. The control unit detects the reset signal, initializes parameters first, and only after initialization completes does it execute the power-off-sequence process. This allows the system to accept and process command inputs during the initialization phase while maintaining display quality through subsequent charge discharge.
Solution Approach 2:
The halting process is segmented into two distinct phases: (1) parameter initialization phase, and (2) power-off-sequence execution phase. This segmentation allows command processing to occur during the first phase while the second phase focuses on discharge operations, thereby achieving both parameter adaptability and display quality maintenance.
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
Ensures that command inputs are processed during the power-off sequence, preventing display degradation and allowing for optimal operation by maintaining specific driving parameters, thereby improving the reliability and efficiency of the liquid crystal display.
Implementation Method 1
In electro-optical devices such as liquid crystal devices, a plurality of pixels aligned so as to correspond to the intersections of a plurality of scanning lines and a plurality of data lines is driven by driving circuits
Implementation Method 2
turn-off voltage is applied to all pixels after halting display (referred to as power-off-sequence process hereinbelow). With this technique, since electric charge stored in the pixels is discharged before halting display
Data Source
AI summary
A controller includes a register storing a group of parameters including a driving-control parameter for controlling a data line driving circuit and a scanning line driving circuit, a parameter controller for updating values of the group of parameters stored in the register and for initializing the values of the group of parameters stored in the register when a reset signal RES is input, and a driving controller for controlling a data line driving circuit and a scanning line driving circuit in accordance with the driving-control parameter stored in the register. The driving controller controls the data line driving circuit and the scanning line driving circuit such that turn-off voltage is applied to a plurality of pixels after the parameter controller updates the values of the group of parameters by the reset signal.