Light-Emitting Pixel Circuit With Reference-Signal Correction
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Solution Overview
Problem
As pixel size decreases in high-resolution light emitting devices, parasitic capacitance between elements and wiring patterns increases, leading to potential changes in transistor gate potentials, which can cause image quality deterioration.
Innovation Solution
A light emitting device with a pixel configuration that includes a driving transistor, a light emission control transistor, a write transistor, and capacitive elements, utilizing a correction period for reference signal writing, followed by a write period for luminance signal writing, and a light emission period, with the light emission control transistor becoming conductive after the correction period and before the write period to minimize potential changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel size decreases to increase resolution, then resolution is improved, but parasitic capacitance between elements and wiring patterns increases
Solution Approach 1:
The patent applies preliminary action by introducing a correction period before the write period, during which a reference signal is written to the control terminal to compensate for parasitic capacitance effects. This preliminary correction action eliminates the harmful influence of parasitic capacitance before the actual luminance signal is written, allowing the system to achieve high resolution without suffering from increased parasitic capacitance.
2Area of moving object
If element size decreases to reduce pixel area, then pixel density is improved, but gate potential stability deteriorates
Solution Approach 1:
The correction period performs preliminary action by writing a reference signal to the control terminal before the luminance signal is written. This ensures that the gate potential is stabilized and any parasitic capacitance effects are compensated for in advance, maintaining gate potential stability even when element size is reduced to increase pixel density.
Solution Approach 2:
The patent implements feedback by using a reference signal that compensates for the effects of parasitic capacitance. The control terminal receives feedback through the capacitive element, allowing the system to adjust and stabilize the gate potential despite changes in element size and parasitic capacitance.
3Length of stationary object
If distance between element and wiring pattern decreases to reduce pitch, then pixel density is improved, but parasitic capacitance influence increases
Solution Approach 1:
The correction period performs preliminary compensation by writing a reference signal to the control terminal before the luminance signal is written. This preliminary action counteracts the increased parasitic capacitance influence that results from decreased distance between elements and wiring patterns, allowing high pixel density without excessive parasitic capacitance effects.
Data Source
AI summary
A light emitting device including a pixel is provided. The pixel includes a light emitting element, a driving transistor connected to the light emitting element, a control transistor arranged between the driving transistor and a supply line and a write transistor arranged between a control terminal of the driving transistor and a signal line. One frame period includes a correction period during which the write transistor is rendered conductive and a reference signal is written in the control terminal, a write period during which the write transistor is rendered conductive and a luminance signal is written in the control terminal, and a light emission period. The control transistor is rendered conductive during a conductive state of the write transistor in the correction period, and is rendered conductive after the correction period and before the write period.