Pixel Driving Circuit Pulse Amplitude Width Modulation
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Solution Overview
Problem
Display panels using micro light-emitting diodes or sub-millimeter light-emitting diodes face issues with poor low gray-scale uniformity, and external compensation circuits used to address this problem have high power consumption.
Innovation Solution
A pixel driving circuit comprising a light emitting device, a driving transistor, a pulse amplitude modulation module, and a pulse width modulation module, which controls the amplitude and duration of the driving current to improve display uniformity without the need for external compensation circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If external compensation circuits are used to improve low gray-scale uniformity, then display uniformity is improved, but power consumption increases
Solution Approach 1:
The patent merges the compensation function with the existing pixel driving circuit by integrating a compensation transistor and compensation capacitor into the pixel circuit structure. This eliminates the need for separate external compensation circuits while maintaining the ability to compensate for threshold voltage shifts and improve low gray-scale uniformity, thereby reducing overall power consumption.
Solution Approach 2:
The pixel driving circuit performs self-compensation by using the compensation transistor to detect and correct threshold voltage shifts within the circuit itself. The compensation capacitor stores the compensation charge that adjusts the driving transistor's threshold voltage, enabling the circuit to compensate for its own variations without requiring external intervention or additional power-consuming components.
2Manufacturing precision
If external compensation circuits are used to improve low gray-scale uniformity, then display uniformity is improved, but device complexity increases
Solution Approach 1:
The patent combines the compensation functionality into the existing pixel driving circuit structure, merging the compensation transistor and compensation capacitor with the driving transistor and data line connections. This integration eliminates separate external compensation circuits and reduces overall device complexity while achieving the same uniformity improvement.
Solution Approach 2:
The compensation transistor serves multiple functions: it acts as part of the pixel driving circuit and simultaneously performs compensation for threshold voltage shifts. The compensation capacitor both stores compensation charge and influences the driving characteristics of the driving transistor, reducing the need for separate dedicated compensation components.
Data Source
AI summary
The invention provides a pixel driving circuit, a driving method thereof, and a display panel. The pixel driving circuit includes electrically connected light emitting device, driving transistor, pulse amplitude modulation module, and pulse width modulation module. The driving transistor generates a driving current to drive the light emitting device to emit light, and the pulse amplitude modulation module is configured to output a pulse amplitude modulation voltage to the driving transistor to control an amplitude of the driving current. The pulse width modulation module is configured to control a duration for which the driving transistor outputs the driving current based on a swept frequency voltage. By combining the pulse amplitude modulation module and the pulse width modulation module, uniformity of the display panel is compensated without the need to set up an external compensation circuit, which is beneficial to reducing power consumption. The display panel includes the pixel driving circuit.