Laser Beam Scanning Display Control With Adaptive Resonance Tracking
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Solution Overview
Problem
Existing display devices face inefficiencies in power consumption and image distortion due to changes in resonant frequency of MEMS drivers, which are not optimally addressed by fixed control update rates, particularly in portable devices like head-mounted displays.
Innovation Solution
Adaptive adjustment of control system update rates based on environmental changes and mirror properties to optimize power consumption while maintaining image quality, using sensors to monitor resonant frequency and adjust clock rates accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fixed high control update rates are used to maintain resonance frequency tracking, then image quality and control precision are maintained, but power consumption increases unnecessarily when environmental conditions are stable
Solution Approach 1:
The control update rate is made dynamic rather than fixed. The system adjusts the update rate of control loops based on detected changes in resonant frequency. When resonant frequency changes rapidly (indicating environmental changes), the update rate increases to maintain tracking precision. When resonant frequency is stable, the update rate decreases to reduce power consumption. This dynamic adaptation resolves the contradiction between maintaining precision and reducing energy use.
Solution Approach 2:
The system changes the operational parameter (control update rate) based on the state of the system (resonant frequency stability). By monitoring resonant frequency drift and adjusting the control loop update rate accordingly, the system optimizes the balance between tracking precision and power consumption. This parameter adaptation allows the system to operate efficiently under varying environmental conditions.
2Use of energy by moving object
If fixed low control update rates are used to reduce power consumption, then power efficiency improves, but image distortion occurs when resonant frequency changes due to environmental factors
Solution Approach 1:
The system implements feedback control by continuously monitoring the resonant frequency of the MEMS driver and using this information to adjust the control update rate. When feedback detects rapid resonant frequency changes, the system increases the update rate to prevent image distortion. When feedback shows stable resonant frequency, the system reduces the update rate to save power. This feedback mechanism ensures reliability is maintained only when necessary.
Solution Approach 2:
The control system transitions from a static fixed update rate to a dynamic adaptive update rate that responds to environmental conditions. The update rate is adjusted in real-time based on resonant frequency measurements, allowing the system to maintain image quality during environmental changes while reducing power consumption during stable periods.
3Measurement precision
If multiple control loops run at fixed high clock rates to maintain resonance actuation and open angle, then control precision is maintained, but power consumption increases unnecessarily when mirror properties change slowly
Solution Approach 1:
The system makes the clock rates of control loops dynamic rather than fixed. Each control loop's update rate is adjusted based on the detected rate of change of mirror properties (resonant frequency, Q factor). When mirror properties change rapidly, all control loops operate at higher rates to maintain precision. When mirror properties are stable, control loops reduce their update rates to minimize power consumption. This dynamic adaptation resolves the contradiction between maintaining control precision and reducing energy consumption.
Solution Approach 2:
The system changes the operational parameters (clock rates of control loops) based on the state of the mirror properties. By monitoring resonant frequency and Q factor variations, the system adjusts the update rates of control loops accordingly. This parameter adaptation allows the system to maintain control precision when necessary while reducing power consumption during stable operation periods.
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
The solution enables efficient power management and maintains image quality by dynamically adjusting control loop rates in response to environmental and mirror property variations, reducing unnecessary power consumption and improving overall efficiency.
Implementation Method 1
it is desirable for the MEMS driver to be driven at a frequency close to its resonant frequency
Data Source
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AI summary
The techniques disclosed herein provide methods and systems that adaptively adjust control system update rates to optimize power consumption for laser beam scanning display devices. A display device can adjust an update rate based on changes within the system and/or changes of a surrounding environment, e.g., vibration level, a humidity level, a temperature, a resonant frequency, and/or an age of a device. As variations of the environmental properties change, the device can increase or decrease the control system update rates. Additionally, or alternatively, the system can perform a resonance calibration process to determine a resonant frequency. Based on a change in a determined resonant frequency, the system may increase or decrease the control system update rates. By dynamically controlling the system update rates based on environmental and/or physical properties of a device, the device can optimize power consumption while maintaining a desirable image quality.