Display Panel Mobility Correction Circuit Timing Control
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Solution Overview
Problem
Existing display panel devices face variations in mobility correction due to wiring delays, leading to inconsistent luminance across pixels, especially when displaying different shades of gray, causing poor shading and image quality issues.
Innovation Solution
The solution involves a display panel device with a controller that precisely controls the mobility correction period by using separate switches for starting and ending the mobility correction, ensuring that the charge accumulated in a capacitor is discharged accurately, and by setting the voltage values to prevent luminescence before the end of the correction period, thereby maintaining consistent luminance across pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the mobility correction period is extended to improve correction accuracy, then luminance consistency improves, but wiring delays cause variations across different shades of gray
Solution Approach 1:
The patent applies preliminary action by performing mobility correction before the luminescence period begins. The correction is executed during a dedicated correction period that precedes the actual display period, ensuring that transistor mobility variations are compensated before they would affect luminance output. This timing prevents the correction from being influenced by wiring delays that occur during active display operations.
Solution Approach 2:
The patent implements dynamics by making the correction period a variable parameter that can be adjusted based on display conditions. The correction period duration is dynamically set to be sufficiently long to achieve accurate mobility correction, while being distinct from and shorter than the luminescence period. This dynamic adjustment allows optimal correction without being constrained by fixed timing requirements.
2Measurement precision
If separate switches are used to control the mobility correction period, then correction timing precision improves, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the control of the mobility correction period into two distinct switch operations: a first switch that initiates the correction period and a second switch that terminates it. This segmentation allows independent and precise control of the correction period start and end times, enabling accurate timing without requiring complex integrated control logic. Each switch can be controlled separately based on specific timing signals.
Solution Approach 2:
The patent uses switch control signals as intermediaries to coordinate the mobility correction timing. These control signals act as mediators between the display control circuitry and the pixel circuit switches, translating high-level timing requirements into precise switch activation and deactivation events. This intermediary layer simplifies the overall control architecture while maintaining precise timing control.
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 approach effectively reduces variations in the mobility correction period across all shades of gray, leading to improved image quality and consistent luminance, even in large display panels with increased pixel counts.
Implementation Method 1
a first capacitor having a first capacitor electrode and a second capacitor electrode that holds a capacitor voltage
Implementation Method 2
a luminescence element including a first luminescence electrode and a second luminescence electrode... allows a drain current corresponding to the capacitor voltage to flow through the luminescence element, the gate electrode being connected to the first capacitor electrode
Data Source
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AI summary
A display panel device includes: an organic EL element (13); a capacitor (14) including first and second capacitor electrodes; a driving transistor (11) having a gate connected to the first capacitor electrode for allowing a drain current to flow through the organic EL element (13) and a source connected to the second capacitor electrode; a selecting transistor (12) switchably interconnecting a data line (20) and the first capacitor electrode for supplying a signal voltage to the capacitor (14); a switching transistor (16) switchably interconnecting the drain of the driving transistor (11) and a positive power line (24); and a controller. The controller is configured to: turn ON the selecting transistor (12) while the switching transistor (16) is ON to supply the signal voltage to the capacitor and flow a current between the source of the driving transistor (11) and the second capacitor electrode; and, after predetermined time period, turn OFF the switching transistor (16) to cause non-conduction between the positive power line (24) and the drain of the driving transistor (11).