Display Device Power Reduction via Data Line Pre-Charging
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Solution Overview
Problem
In display devices with light-emitting elements, such as organic electroluminescence elements, the horizontal scanning period including an initialization period results in increased power consumption due to the charge and discharge of various capacitors.
Innovation Solution
The display device incorporates a light-emitting element, a data line, a wiring line, a first constant potential line, a first transistor for supplying a drive current to the light-emitting element, a second transistor for coupling the data line to the first constant potential line, and a switching element for coupling the data line to the wiring line, thereby reducing power consumption by minimizing charge and discharge of capacitors during initialization periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the anode of the light-emitting element is reset to the potential Vorst during the horizontal scanning period, then the charge remaining at the coupling node is discharged, but power consumption increases due to charge and discharge of various capacitors
Solution Approach 1:
The patent applies preliminary action by resetting the data line to a predetermined potential before the initialization period begins. Specifically, a switching element is used to connect the data line to a constant potential line at a timing before the initialization period starts, so that when the initialization period begins, the data line is already at the correct potential and capacitors do not need to be charged or discharged, thereby reducing power consumption while ensuring proper charge discharge at the coupling node
2Use of energy by moving object
If the data line is connected to the constant potential line during initialization, then power consumption is reduced, but the data line cannot be properly initialized
Solution Approach 1:
The patent segments the initialization process into two distinct phases: a first initialization period where the data line is connected to the constant potential line to reduce power consumption, and a second initialization period where the switching element connects the data line to the constant potential line to complete the initialization. This segmentation allows both power savings and proper initialization to be achieved
3Ease of operation
If various capacitors are charged and discharged during the horizontal scanning period, then the light-emitting element can be properly controlled, but unnecessary power consumption occurs
Solution Approach 1:
The patent applies preliminary action by pre-charging or pre-discharging capacitors before the horizontal scanning period begins. The switching element is controlled to connect the data line to the constant potential line before initialization, so that when the actual scanning and control operations occur, the capacitors are already in their proper states and do not need to be charged or discharged, eliminating unnecessary power loss while maintaining control precision
Data Source
AI summary
A display device includes a light-emitting element, a data line, a wiring line, a first constant potential line to which a first constant potential is supplied, a first transistor configured to supply a drive current corresponding to a video signal supplied via the wiring line and the data line to the light-emitting element, a second transistor configured to electrically couple the data line to the first constant potential line, and a switching element configured to electrically couple the data line to the wiring line.