Scanning Mirror Resonant Frequency Tuning via Flexure Tension

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Solution Overview

Problem

Scanning display systems face challenges in synchronizing the resonant frequency of scanning mirrors with video data frame rates due to manufacturing variances and changes over time, leading to issues with frame display latency and the need for costly buffers or complex locking mechanisms, especially in low-latency applications like virtual reality head-mounted displays.

Innovation Solution

A scanning mirror system with an electromechanical actuator system that adjusts the resonant frequency by changing tension in supporting flexures or redistributing mass, allowing dynamic synchronization with video data frame rates without large buffers or frame locking mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the resonant frequency of the scanning mirror is adjusted to synchronize with video data frame rates, then frame display synchronization is improved, but device complexity increases due to the need for electromechanical actuator systems

Engineering Contradiction:
Improveframe display synchronizationVSAvoidelectromechanical actuator system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by adjusting the resonant frequency of the scanning mirror through an electromechanical actuator system. The actuator modifies physical parameters such as tension in supporting flexures or mass distribution to dynamically tune the resonant frequency, enabling synchronization with video frame rates while maintaining system reliability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system implements feedback control by continuously monitoring the resonant frequency and adjusting the electromechanical actuator to maintain synchronization with video data frame rates. This closed-loop approach ensures reliable frame display synchronization despite manufacturing variances or environmental changes

Inventive Principle:
Principle #23Feedback

2Measurement precision

If manufacturing precision is increased to reduce resonant frequency variances, then synchronization accuracy is improved, but manufacturing cost and complexity increase

Engineering Contradiction:
Improveresonant frequency accuracyVSAvoidmirror fabrication tolerance
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

Instead of relying on static manufacturing precision, the patent employs dynamic adjustment through the electromechanical actuator system. The resonant frequency can be tuned in real-time to compensate for manufacturing variances, shifting the requirement from static fabrication tolerance to dynamic controllability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes physical parameters such as flexure tension or mass distribution to adjust resonant frequency, allowing post-manufacturing tuning that compensates for fabrication tolerances without requiring ultra-precise manufacturing

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If tension in supporting flexures is adjusted to change resonant frequency, then frequency tuning is achieved, but mechanical stress on components increases

Engineering Contradiction:
Improveresonant frequency tuning rangeVSAvoidstress on supporting flexures
Core Design Contradiction:
Adaptability or versatilityVSStress or pressure

Solution Approach 1:

The patent utilizes parameter changes by adjusting the tension in supporting flexures through the electromechanical actuator system. This modifies the resonant frequency of the scanning mirror, enabling frequency tuning while monitoring stress levels to prevent component damage

Inventive Principle:
Principle #35Parameter changes

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

Enables proper frame display by dynamically adapting to resonant frequency variances, ensuring harmonically oscillating scanning mirrors align with video data frame rates, reducing latency and complexity in display systems.

Implementation Method 1

adjusting the resonant frequency by changing tension in supporting flexures

Methodology Applied
Scientific EffectTension: Tension

Implementation Method 2

scanning mirror configured to scan light from the light source in at least one direction at a resonant frequency of the scanning mirror

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 3

ensuring harmonically oscillating scanning mirrors align with video data frame rates

Methodology Applied
Scientific EffectHarmonic oscillation: Harmonic Oscillator

Data Source

PatentEP3814826B1Adjusting a resonant frequency of a scanning mirror
Publication Date: 2023.06.28 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3814826B1 patent drawingFigure 1
  • EP3814826B1 patent drawingFigure 2~3
  • EP3814826B1 patent drawingFigure 4A~4B

AI summary

Examples are disclosed that relate to scanning display systems. One example provides a display device comprising a controller, a light source, and a scanning mirror system. The scanning mirror system comprises a scanning mirror configured to scan light from the light source in at least one direction at a resonant frequency of the scanning mirror, and an electromechanical actuator system coupled with the scanning mirror and being controllable by the controller to adjust the resonant frequency of the scanning mirror.