Laser Projection Clock Regulation for Uniform MEMS Mirror Illumination
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Solution Overview
Problem
Laser projection systems using MEMS micromirrors produce non-uniform brightness on the screen due to varying rotation speeds of the micromirrors, leading to low illumination performance, and existing compensation methods are computationally intensive and energy-consuming.
Innovation Solution
A control device with a clock regulation circuit that generates a variable frequency regulated clock signal based on the movement of high-frequency MEMS micromirrors, adjusting the laser pulse emission to achieve uniform illumination by synchronizing with the micromirror movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed frequency clock signal is used to drive the laser source and MEMS micromirrors, then the system operation is simple, but the illumination uniformity deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed frequency clock signal to a variable frequency clock signal that adapts to the instantaneous rotation speed of the MEMS micromirrors. The control device adjusts the laser pulse emission frequency in real-time to match the mirror rotation speed, ensuring uniform spatial density of illuminated points despite the dynamic nature of the rotating mirrors.
Solution Approach 2:
The patent implements feedback through the clock regulation circuit that senses the variation of the reconstructed signal representing the mirror system's movement trend. This feedback mechanism allows the system to automatically adjust the clock signal frequency based on the actual rotation speed of the MEMS micromirrors, closing the control loop to maintain illumination uniformity.
2Illumination intensity
If a variable frequency clock signal is used to compensate for non-uniform brightness, then the illumination uniformity is improved, but the device complexity increases
Solution Approach 1:
The patent introduces an intermediary component - the clock regulation circuit - that acts as a mediator between the mirror driving circuit and the laser driving circuit. This intermediary generates the variable frequency clock signal based on the reconstructed movement signal, simplifying the overall control architecture compared to using a dedicated GPU while achieving the desired illumination uniformity.
3Illumination intensity
If a dedicated GPU is used to compensate for non-uniform brightness, then the illumination uniformity is improved, but the energy consumption increases
Solution Approach 1:
The patent replaces the computational approach using a dedicated GPU with a hardware-based clock regulation circuit that generates variable frequency signals. This substitution eliminates the need for complex computational processing and graphics rendering, significantly reducing energy consumption while achieving the same illumination uniformity compensation effect.
Data Source
AI summary
A laser projection system includes a mirror system and a laser source. A control device for the system includes: a mirror driving circuit generating at least one driving signal to drive a movement of the mirror system; a clock regulation circuit generating a regulated clock signal having a variable frequency; and a laser driving circuit that drives the emission of a laser beam by the laser source as a function of the regulated clock signal. The clock regulation circuit is configured to: generate a reconstructed signal representative of a trend over time of the driven movement of the mirror system; sense a variation over time of the reconstructed signal; and regulate the frequency of the regulated clock signal, as a function of the variation over time of the reconstructed signal.