Electronic Device Brightness Control Circuit
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Solution Overview
Problem
Conventional electronic devices with light-emitting units face issues in maintaining consistent brightness due to variations in manufacturing processes, leading to inconsistent display quality despite using the same driving voltage.
Innovation Solution
The design incorporates a circuit structure with a light-emitting unit, a first switch transistor, and a plurality of pulse switches, along with storage capacitors and second switches, which allow for precise control of pulse signals and data signals to achieve varying brightness levels corresponding to different gray levels by adjusting the operation times and capacitance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional light-emitting units are used with the same driving voltage, then the manufacturing process is simple, but the brightness consistency deteriorates due to manufacturing variations
Solution Approach 1:
The patent applies preliminary action by pre-storing reference voltages in multiple storage capacitors before the light-emitting phase. During the writing phase, the circuit pre-charges capacitors with different reference voltages, and then during the light-emitting phase, the appropriate stored voltage is selected and applied to compensate for manufacturing variations. This preliminary preparation enables brightness compensation without adding complexity to the manufacturing process.
Solution Approach 2:
The patent changes the voltage parameter dynamically by storing multiple different reference voltages in storage capacitors. Instead of using a fixed driving voltage, the circuit selects and applies different voltage levels from the stored reference voltages based on compensation needs. This parameter change allows the same light-emitting unit to operate at different brightness levels to compensate for manufacturing variations.
2Measurement precision
If multiple storage capacitors with different reference voltages are used, then brightness control precision is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple storage capacitors into a single pixel circuit structure, combining their functions within one integrated unit. The multiple storage capacitors share common circuit elements such as the light-emitting element, switch transistors, and control lines. This merging approach enables precise brightness control through multiple voltage levels while avoiding the complexity of completely separate circuit modules.
Solution Approach 2:
The circuit components serve multiple functions: the switch transistors act as both selection switches for different storage capacitors and as driving transistors for the light-emitting element; the storage capacitors store reference voltages and also function as part of the overall pixel circuit structure. This multi-functionality reduces the need for additional dedicated components, thereby controlling device complexity while maintaining brightness control precision.
3Manufacturing precision
If pulse switches with different operation times are used, then gray level accuracy is improved, but the control system complexity increases
Solution Approach 1:
The patent applies periodic action by dividing the frame period into distinct phases: a writing phase for charging storage capacitors and a light-emitting phase for displaying images. Within the light-emitting phase, different pulse widths are applied periodically to control the duration of current flow through the light-emitting element. This periodic structure with varying pulse widths enables accurate gray level control while maintaining a relatively simple control system that follows a regular temporal pattern.
Data Source
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Figure 3A
AI summary
An electronic device includes a power source unit and an electronic unit. The electronic unit includes a first switch, a light-emitting unit, and a plurality of pulse switches. The first switch is coupled to the power source unit, and the first switch has a gate electrode. The light-emitting unit is coupled to the first switch. The plurality of pulse switches are coupled to the gate electrode of the first switch. Therefore, the brightness of the light-emitting unit may be effectively controlled to improve the quality of the electronic device.