Alternating Pixel Circuit for OLED Threshold Shift Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In organic light-emitting display devices, power consumption increases due to charging and discharging of data lines with data and reference voltages, and luminance unevenness occurs due to capacitance and resistance deviations among pixels, leading to deteriorating electrical characteristics of driving elements.
Innovation Solution
A pixel circuit design with alternating drivers for each frame, incorporating switch elements and capacitors to manage data and reference voltages, reducing load on driving elements and preventing threshold voltage shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data lines are charged and discharged with data voltage and reference voltage in one horizontal period cycle, then the data lines can be driven to display images, but power consumption increases
Solution Approach 1:
The patent applies periodic action by alternating the driving of data lines between two different drivers in successive horizontal periods. Driver 1 drives data lines in odd horizontal periods while Driver 2 drives data lines in even horizontal periods, creating a periodic switching pattern that reduces overall power consumption by allowing capacitive coupling to maintain signals without active driving in every period.
2Use of energy by moving object
If data lines are driven alternately by two drivers in different horizontal periods, then power consumption is reduced, but the driving scheme becomes more complex
Solution Approach 1:
The patent merges the functionality of two drivers into a unified system where Driver 1 and Driver 2 share common data lines and control logic. The switching between drivers is coordinated through shared horizontal period signals, and both drivers interface with the same pixel circuits, effectively combining their operations to reduce power consumption while managing complexity through integration.
3Ease of manufacture
If there is deviation between capacitance and resistance of OLED among pixels due to process deviations, then manufacturing is simplified, but luminance unevenness among pixels becomes severe
Solution Approach 1:
The patent implements feedback through pixel circuits that include compensation mechanisms for OLED parameter variations. The driving elements continuously adjust their operation based on the actual capacitance and resistance values of connected OLEDs, detecting deviations from nominal values and compensating accordingly to maintain uniform luminance across all pixels despite manufacturing variations.
4Device complexity
If driving elements control driving current based on voltage Vgs, then the circuit structure is simplified, but electrical characteristics deteriorate over time due to threshold voltage shifts
Solution Approach 1:
The patent applies preliminary action by pre-charging data lines to appropriate voltage levels before active display periods. Capacitive coupling structures store voltage information in advance, and the alternating driver scheme prepares signal paths beforehand, allowing driving elements to operate with reduced stress and fewer threshold voltage shifts over time, thereby improving long-term reliability.
Data Source
AI summary
Disclosed in the present disclosure is a pixel circuit. The pixel circuit according to an embodiment of the present disclosure includes a first node connected to a driving voltage line configured to receive a first constant voltage, a third node connected to a fourth node that is connected to a light-emitting element, a first driver including a first driving element, and a second driver including a second driving element. The first driver and the second driver may be alternately driven for each frame. In a pixel circuit according to the present disclosure, a threshold voltage shift phenomenon and a deterioration phenomenon of the driving element may be prevented or suppressed.