LC Resonant Driver Tuning for MEMS Mirror Power Transfer
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Solution Overview
Problem
Laser beam scanning display devices face inefficiencies and reliability issues due to misalignment of resonant frequencies between the LC resonance driver and MEMS mirrors, leading to suboptimal power transfer and increased power consumption.
Innovation Solution
A dynamic resonance control system that adjusts the resonant frequency of the LC resonance circuit using a variable capacitance circuit responsive to a sense signal from the MEMS mirror, optimizing energy transfer by aligning the resonant frequencies and mitigating the impact of parasitic capacitances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a fixed resonant frequency is used in the LC resonance driver, then the circuit design is simple, but power transfer efficiency deteriorates due to frequency misalignment with the MEMS mirror
Solution Approach 1:
The patent implements dynamic resonant frequency adjustment by varying the capacitance value in the LC resonance circuit based on the operating conditions and MEMS mirror resonant frequency. This dynamic adaptation allows the driver to maintain optimal power transfer efficiency across different operating points while managing the complexity through controlled variability rather than fixed design
Solution Approach 2:
The patent changes the electrical parameter (capacitance) of the LC resonance circuit to match the resonant frequency of the MEMS mirror. By adjusting the capacitance value, the system optimizes power transfer efficiency without requiring complete redesign of the circuit architecture, thus balancing performance improvement with manageable complexity
2Loss of energy
If the resonant frequency is adjusted to match the MEMS mirror, then power transfer efficiency improves, but the system complexity increases due to additional control circuits
Solution Approach 1:
The patent employs feedback mechanisms where the system monitors the resonant conditions and adjusts the capacitance accordingly. This feedback loop ensures that the LC resonance driver maintains optimal alignment with the MEMS mirror resonant frequency, minimizing power loss while using automated control to manage the complexity of frequency adjustment
Solution Approach 2:
The system performs self-adjustment of the resonant frequency by automatically detecting and adapting to the MEMS mirror's resonant characteristics. This self-service capability reduces the need for external complex control systems while achieving optimal power transfer efficiency through autonomous frequency matching
3Reliability
If parasitic capacitances are present in the LC circuit, then the resonant frequency shifts, but adding compensation circuits increases device complexity
Solution Approach 1:
The patent compensates for parasitic capacitance effects by dynamically adjusting the main capacitance parameter in the LC circuit. This parameter adjustment counteracts the frequency shifts caused by parasitic elements, maintaining resonance frequency stability without requiring separate complex compensation circuits for each parasitic effect
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
Improves energy efficiency and reliability by ensuring peak signal levels are achieved, reducing unnecessary power consumption and enhancing the overall performance of the laser beam scanning display devices.
Implementation Method 1
An LC resonance driver is used to drive the PE actuators to achieve the desired operating frequency of the MEMS mirror(s)
Implementation Method 2
One or more Piezo-Electric (PE) actuators are utilized to drive the MEMS mirror that deflects the laser
Data Source
AI summary
Techniques are described herein for dynamically adjusting a resonant frequency of a resonance circuit to optimize power transfer to a mirror device such as a MEMS mirror. A variable capacitance circuit can be operated responsive to a bias control signal. A capacitance control circuit can vary the bias control signal to the resonance circuit responsive to a sense signal. The sense circuit is configured to generate the sense signal responsive to an output of the mirror device. By monitoring a signal level from the output of the mirror device 130, and adjusting the bias control signal of the resonance circuit, the exact resonance frequency of the resonance circuit can be adjusted until a peak signal level is observed, thus improving the efficiency of the energy transferred from the driver circuit 110 to the mirror device 130, and counteracting the impact of parasitic capacitances on the resonance.