Display Driving Method Using Segmented Mobility Correction Signals
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Solution Overview
Problem
Organic electroluminescent (EL) display apparatuses face challenges in achieving high definition and luminance due to variations in drive transistor mobility, leading to uneven pixel luminance and reduced mobility correction time, which affects image quality.
Innovation Solution
A display apparatus with a pixel array featuring a drive transistor, a holding capacitor, and mobility correction means, where a correction signal value lower than the signal value is used to extend the mobility correction time, allowing proper correction and light emission operations to maintain high image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If higher definition and luminance are pursued, then display quality is improved, but mobility correction time becomes insufficient leading to uneven pixel luminance
Solution Approach 1:
The patent applies preliminary action by performing mobility correction using a correction signal before the actual light emission operation. The correction signal is supplied to the holding capacitor in advance to adjust transistor mobility variations, ensuring uniform pixel luminance before the display operation begins. This preliminary correction prevents luminance unevenness without compromising the timing of high-definition and high-luminance display operations.
2Loss of time
If correction signal value is lowered, then mobility correction time is extended, but signal accuracy may be compromised
Solution Approach 1:
The patent segments the signal into two distinct components: a correction signal and a light emission signal. The correction signal, which has a lower voltage level than the actual display signal, is used exclusively for mobility correction purposes. This segmentation allows the system to use a reduced-amplitude correction signal that extends correction time while maintaining full signal accuracy for the subsequent light emission operation, as the two signals serve separate functions and are applied at different times.
Data Source
AI summary
A display apparatus includes the following components. A pixel array includes matrix-arranged pixel circuits each including at least a light emitting element, a drive transistor in which a drive voltage is applied between the drain and the source to supply a current corresponding to a signal value supplied between the gate and the source to the light emitting element, and a holding capacitor which is connected between the gate and the source of the drive transistor and which holds the input signal value. A mobility correction operating unit supplies the drive voltage to the transistor while the capacitor holds a correction signal value lower than the signal value to perform mobility correction for the transistor. A light emission operating unit allows the capacitor to hold the signal value and supplies the drive voltage to the transistor after correction to perform light emission at a luminance corresponding to the signal value.