Pixel Circuit for Micro-LED Grayscale Control
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Solution Overview
Problem
Micron-sized light emitting diode (µLED) display panels face issues with low light emitting efficiency and unstable light color due to operating at low current density during low grayscale displays, as the light color coordinates fluctuate significantly at lower grayscale levels.
Innovation Solution
A pixel circuit with a first adjusting circuit to control the magnitude of the driving current and a second adjusting circuit to control the time duration of the driving current, allowing the light emitting element to operate at a high current density by adjusting the light emitting time, thereby stabilizing the light color and improving efficiency across various grayscales.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If µLEDs operate at low current density to achieve low grayscale display, then power consumption is reduced, but light emitting efficiency decreases and light color becomes unstable
Solution Approach 1:
The patent applies periodic action by controlling the µLED to emit light in pulsed intervals rather than continuous operation. The light emitting control circuit turns the µLED on and off at specific time points during the frame period, allowing the µLED to operate at high current density only during brief light emitting intervals while remaining off during other periods. This achieves low average power consumption while maintaining high light emitting efficiency and stable light color during actual emission, as the µLED operates at optimal current density during its active periods.
2Illumination intensity
If µLEDs operate at low current density for low grayscale display, then brightness is reduced, but light emitting efficiency and color stability deteriorate
Solution Approach 1:
The patent applies dynamics by making the µLED's operating state changeable between high current density (during light emitting intervals) and zero current density (during off intervals). The light emitting control circuit dynamically adjusts the µLED's operation timing based on grayscale requirements, allowing the µLED to operate at high current density during brief periods to maintain color stability and efficiency, while achieving various brightness levels through temporal control rather than relying on low current density operation.
3Loss of energy
If the driving current magnitude is increased to maintain high light emitting efficiency, then power consumption increases, but energy waste occurs during non-light-emitting periods
Solution Approach 1:
The patent applies periodic action by controlling the µLED to emit light in pulsed intervals rather than continuous operation. The light emitting control circuit turns the µLED on and off at specific time points during the frame period, allowing the µLED to operate at high current density only during brief light emitting intervals while remaining off during other periods. This achieves low average power consumption while maintaining high light emitting efficiency and stable light color during actual emission, as the µLED operates at optimal current density during its active periods.
Data Source
Figure 1~2A
Figure 2B~3B
Figure 4~5
AI summary
Disclosed are a pixel circuit and a driving method thereof, an array substrate and a display apparatus. The pixel circuit includes a pixel sub-circuit. The pixel sub-circuit includes a first adjusting circuit and a second adjusting circuit. The first adjusting circuit is configured to receive a first data signal and a light emitting control signal to control a magnitude of a driving current used for driving a light emitting element to emit light; the second adjusting circuit is configured to receive a second data signal and a time control signal to control a time duration in which the driving current is applied to the light emitting element; and the time control signal changes within a time period during which the light emitting control signal allows the driving current to be generated. The pixel circuit can control the time duration in which the driving current is applied to the light emitting element, so that the light emitting element can realize display of various grayscales by controlling the light emitting time of the light emitting element, on the premise that the light emitting element operates at a relatively high current density.