Common Line Voltage Control for Display Apparatus
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Solution Overview
Problem
Conventional display apparatuses face issues with erroneous lighting of light emitting elements due to parasitic capacitance, particularly during periods when the voltage is not applied, leading to excessive reverse voltage and open or short-circuit failures.
Innovation Solution
The display apparatus incorporates charging and discharging devices connected to common lines to maintain voltages at predetermined values when the source driver is not applying voltage, preventing excessive reverse voltage and reducing power consumption by using semiconductor switches and voltage supply units to manage voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the source driver does not apply voltage to common lines during certain periods, then power consumption is reduced, but parasitic capacitance causes erroneous lighting of light emitting elements
Solution Approach 1:
The patent applies preliminary action by proactively charging or discharging the common lines before the source driver applies or stops applying voltage. The charging device charges common lines to a predetermined voltage level before the source driver applies voltage, and the discharging device discharges common lines to a predetermined voltage level before the source driver stops applying voltage. This preliminary voltage management prevents parasitic capacitance from causing erroneous lighting while maintaining power efficiency.
2Reliability
If voltage is maintained at high levels on common lines, then light emitting elements light up correctly, but excessive reverse voltage causes open or short-circuit failures
Solution Approach 1:
The patent implements feedback control through charging and discharging devices that continuously monitor and adjust the voltage levels on common lines. When the voltage on a common line drops below a predetermined threshold, the charging device activates to raise it. When the voltage exceeds the predetermined threshold, the discharging device activates to reduce it. This feedback mechanism ensures voltage remains within safe ranges, preventing both incorrect lighting and damage from excessive reverse voltage.
3Reliability
If parasitic capacitance is discharged during voltage-off periods, then erroneous lighting is prevented, but voltage instability occurs on common lines
Solution Approach 1:
The patent uses preliminary action by proactively managing voltage levels before the source driver stops applying voltage. The discharging device is activated in advance to reduce voltage on common lines to a predetermined safe level before the source driver turns off. This prevents voltage instability and erroneous lighting by ensuring parasitic capacitance does not cause unexpected voltage spikes during the voltage-off period.
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 solution effectively prevents erroneous lighting and maintains stable voltage levels, reducing power consumption and minimizing damage from open or short-circuit failures by ensuring voltages remain within safe ranges during periods without applied voltage.
Implementation Method 1
parasitic capacitance of a common line flowing into a drive line
Implementation Method 2
parasitic capacitance of a common line flowing into a drive line
Data Source
AI summary
A display device includes a plurality of common lines, a plurality of drive lines, a plurality of light emitting elements, a source driver, and a sink driver. At least one charging device is connected to at least one of the common lines and configured to increase a voltage of the common lines to a predetermined value when the voltage of the common lines is lower than the predetermined value during a period while the source driver does not apply the voltage. At least one discharging device is connected to at least one of the plurality of common lines and configured to decrease the voltage of the common lines to the predetermined value when the voltage of the common lines is higher than the predetermined value during the period while the source driver does not apply the voltage.