OLED Pixel Circuit Segmented Voltage Refreshing for High Contrast
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In OLED displays, the limited voltage difference between electrodes of thin film transistors in low-voltage manufacturing processes restricts the achievable contrast, as the voltage difference cannot exceed 6 V, limiting the range of data voltages for brightest and darkest points, thereby preventing high-contrast displays.
Innovation Solution
The method involves refreshing data voltages in the pixel circuit using gate signal reference voltages that allow segmented writing within tolerable voltage ranges, expanding the allowable voltage writing range by using demarcation values between voltage ranges, thereby enabling data voltage changes across multiple voltage ranges, allowing higher brightness and contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the voltage difference between electrodes is limited to 6 V in low-voltage manufacturing processes, then manufacturing feasibility is maintained, but display contrast is restricted
Solution Approach 1:
The patent divides the data writing process into multiple segments, each operating within the 6 V voltage difference limit. By segmenting the voltage ranges and using demarcation values as intermediate steps, the system achieves extended effective voltage range without violating the manufacturing constraint, thereby resolving the contradiction between ease of manufacture and display contrast.
Solution Approach 2:
The patent applies preliminary action by first refreshing the data voltage to a demarcation value within the acceptable voltage range, then subsequently adjusting it to the target value. This two-stage approach ensures that no single step exceeds the 6 V voltage difference limit while still achieving the desired high-contrast display effect.
2Reliability
If the data voltage range is limited to -2 V to 6 V, then voltage difference constraints are satisfied, but brightness and contrast performance deteriorate
Solution Approach 1:
The patent segments the target voltage range into multiple sub-ranges, each fitting within the -2 V to 6 V constraint. By using demarcation values as intermediate targets and performing multiple refreshing operations, the system effectively extends the achievable voltage range while maintaining compliance with voltage constraints in each individual operation.
Solution Approach 2:
The patent employs periodic action through multiple refreshing cycles. Instead of attempting to write the full target voltage in a single step, the system performs sequential refreshing operations, each staying within voltage limits, progressively approaching the target voltage and thereby achieving extended effective range through repeated periodic actions.
3Adaptability or versatility
If segmented writing with demarcation values is used, then voltage range expansion is achieved, but writing complexity increases
Solution Approach 1:
The patent applies self-service by having the pixel circuit automatically determine whether a single-step or multi-step refreshing approach is needed based on the target voltage value. The circuit autonomously selects the appropriate writing strategy without requiring external control logic, thereby reducing overall system complexity while still achieving voltage range expansion.
Data Source
AI summary
A method and a device for driving a pixel circuit, and a storage medium are provided. When a current data voltage of a pixel circuit is within a first voltage range and a target data voltage of the pixel circuit is within a second voltage range, the driving method comprises: refreshing a data voltage stored in the pixel circuit with a boundary value between the first voltage range and the second voltage range using a gate signal reference voltage corresponding to the first voltage range; and refreshing the data voltage stored in the pixel circuit with the target data voltage using a gate signal reference voltage corresponding to the second voltage range.