MicroLED Junction Driving for Precise Time-Sequential Color Mixing
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Solution Overview
Problem
Existing LED array technologies face complexity in driving multiple junctions simultaneously, leading to increased circuit load and difficulty in precise color control, particularly in devices requiring fast color mixing and tuning.
Innovation Solution
Implementing sequential driving of vertically stacked polychromic junctions, where each junction is driven individually at different times within a cycle, reducing circuit complexity and allowing precise color control through independent current adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple junctions are driven simultaneously, then color mixing capability is improved, but circuit complexity and load increase
Solution Approach 1:
The patent applies periodic action by sequentially driving different junctions in time-multiplexed fashion. Each junction is activated during specific time intervals within a display refresh cycle, creating periodic on/off patterns that enable color mixing through temporal integration rather than simultaneous activation. This reduces circuit complexity while maintaining color mixing capability.
Solution Approach 2:
The patent transitions from spatial dimension (simultaneous driving of multiple junctions) to temporal dimension (sequential driving over time). By adding the time dimension to the control strategy, the system achieves color mixing through temporal sequencing rather than spatial parallelism, thereby reducing circuit complexity.
2Adaptability or versatility
If multiple junctions are driven simultaneously, then color mixing is achieved, but precise color control becomes difficult
Solution Approach 1:
The patent segments the control of each junction into independent time intervals. By dividing the display refresh cycle into separate time slots for each junction, the system enables independent control of current ratios and durations for each junction, thereby achieving precise color control that would be difficult with simultaneous driving.
Solution Approach 2:
Through periodic sequential activation of junctions within display refresh cycles, the patent enables precise control of color output by adjusting the duty cycle, pulse width, or current magnitude during each periodic interval. This temporal segmentation allows independent optimization of each junction's contribution to the final color.
3Loss of energy
If sequential driving is implemented, then circuit load is reduced, but color mixing speed may be affected
Solution Approach 1:
The patent maintains continuity of useful action by ensuring that sequential junction driving occurs within each display refresh cycle without interruption. The temporal multiplexing is synchronized with the display's natural refresh rate, making the sequential operation appear continuous to the human eye while still reducing circuit load compared to simultaneous driving.
Solution Approach 2:
By aligning the periodic sequential driving pattern with the display refresh rate (typically 60Hz or higher), the patent ensures that color mixing occurs at a speed sufficient for human perception. The temporal frequency of junction activation is high enough that the sequential process appears instantaneous, maintaining effective color mixing speed while reducing circuit load.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Sequential driving reduces circuit load and enables precise color tuning by adjusting current ratios and durations, achieving satisfactory color mixing without simultaneous driving complications.
Implementation Method 1
Light-emitting diodes (LEDs) provide an efficient and relatively smaller source of light
Data Source
AI summary
A lighting system and method of driving an array within the lighting system are disclosed. The array includes vertically-stacked multi-color micro light-emitting diode (microLED) devices that emit light of different colors. Driving circuits and a ground switching circuit are controlled by processing circuitry to sequentially emit the colors of each microLED by independently driving pn junctions of the microLED. Each driving circuit includes multiplexers to receive a sink/source current and selectably provide the sink/source current to a channel based on control signals from the processing circuitry. Dimming of a particular color is effected using a pulse width modulated (PWM) signal to adjust a duty cycle over which the sink/source current is applied to the channel. The ground switching circuit selects another channel using multiplexers, and grounds the channel such that current is limited to flowing through one of the pn junctions at a time.