Pixel Circuit Layout for Time-Shared Micro LED Emission
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Solution Overview
Problem
Micro LED pixel circuits require numerous transistors and signal lines, which hinder aperture ratio and light transmittance in display panels.
Innovation Solution
A pixel circuit design that utilizes a driving transistor, emission control transistor, and multiple light-emitting elements, sharing a common emission control signal and voltage terminals to reduce the number of transistors and signal lines, allowing time-sharing light emission among elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the pixel circuit includes more transistors and signal lines to control multiple micro LEDs, then the emission control capability is improved, but the aperture ratio and light transmittance deteriorate
Solution Approach 1:
The patent merges the control of multiple light-emitting elements (first and second light-emitting elements) into a single pixel circuit structure. The emission control transistor and voltage terminal are shared between multiple light-emitting elements, allowing them to be controlled by common control signals while maintaining independent light emission capability through voltage level differentiation.
Solution Approach 2:
The voltage terminal serves multiple functions: it provides system voltage to the light-emitting elements and simultaneously serves as a control mechanism by adjusting voltage levels to enable or disable specific light-emitting elements. The emission control transistor also functions both as a switch and as part of the current driving path for the light-emitting elements.
2Adaptability or versatility
If the pixel circuit includes more transistors and signal lines for full-color display, then the color display capability is improved, but the light transmittance deteriorates
Solution Approach 1:
The patent employs time-division multiplexing where different light-emitting elements are activated at different time periods. The emission control signal operates in periodic cycles, enabling the first light-emitting element during one period and the second light-emitting element during another period, allowing full-color display through temporal sequencing rather than simultaneous control of all elements.
Solution Approach 2:
The patent adds the time dimension to the control mechanism by using periodic emission control signals and voltage level transitions over time. Instead of controlling all light-emitting elements simultaneously through separate transistors, the system uses temporal sequencing where elements are activated in different time periods, effectively using the time dimension to reduce spatial complexity.
Data Source
AI summary
A pixel circuit includes a driving transistor, an emission control transistor, a first light-emitting element and a second light-emitting element. The emission control transistor is between a first terminal of the driving transistor and a first system voltage terminal. The first light-emitting element is between a second terminal of the driving transistor and a second system voltage terminal. The second light-emitting element is between the second terminal of the driving transistor and a third system voltage terminal. The first light-emitting element is controlled by an emission control signal of a gate terminal of the emission control transistor and a voltage level of the second system voltage terminal. The second light-emitting element is controlled by the emission control signal and a voltage level of the third system voltage terminal. When the first or second light-emitting element emits light, the second and third system voltage terminals have different voltage levels.