Oxide Semiconductor Transistor Charge Management for Display Defects
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Display devices with transistors in oxide semiconductor layers face issues with charge retention during power supply interruptions, leading to display defects when power is resumed.
Innovation Solution
Incorporating transistors with channels formed in oxide semiconductor layers to control current supply to light-emitting elements, allowing for selective electrical connection and disconnection of nodes to manage charge retention and prevent display defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If transistors with oxide semiconductor layer channels are used to control current supply, then field-effect mobility is improved and display device size can be increased, but charge retention during power supply interruptions causes display defects
Solution Approach 1:
The patent applies preliminary action by turning off transistors before power supply interruption occurs. The control circuit detects power supply status and proactively turns off transistors in advance, preventing charge accumulation that would cause display defects when power is restored. This anticipatory measure eliminates the harmful effect of charge retention while preserving the high mobility benefits of oxide semiconductor transistors.
2Loss of energy
If power supply voltage is stopped, then energy consumption is reduced, but charge remains held in pixel nodes causing display defects upon power resumption
Solution Approach 1:
The control circuit performs preliminary action by detecting power supply interruption and turning off transistors before power is completely cut off. This ensures that charge does not accumulate in pixel nodes during the transition, preventing display defects when power is restored while still achieving energy savings during standby mode.
Solution Approach 2:
The control circuit acts as an intermediary between the power supply system and the pixel transistors. It monitors power supply status and mediates the transition by controlling transistor states, ensuring that charge is properly managed during power interruptions and restorations, thus maintaining display quality while enabling energy savings.
3Reliability
If transistors are turned off before and after power supply interruptions, then display defects are suppressed, but additional control circuitry is required
Solution Approach 1:
The control circuit is designed with multi-functionality, serving both as a power management unit and a display quality protection unit. By integrating these functions, the patent avoids adding separate dedicated circuits for each function, thereby suppressing display defects while minimizing the increase in overall device complexity.
Data Source
AI summary
Display defects of a display device are suppressed. The display device includes in each pixel, a light-emitting element, a driving transistor which supplies current to the light-emitting element, and transistors in each of which a channel is formed in an oxide semiconductor layer. A transistor which controls whether to electrically connect a gate and a source of the driving transistor provided in each pixel is provided. The above transistor and a transistor which controls electrical connection between the gate of the driving transistor and another node are transistors in each of which a channel is formed in an oxide semiconductor layer. Accordingly, charge stored in the node electrically connected to the gate of the driving transistor can be arbitrarily retained or released. Consequently, display defects of the display device can be suppressed.