Variable Focal Length Lens Resonance Locking
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Solution Overview
Problem
The variable focal length lens device faces challenges in maintaining accurate image detection due to frequency changes caused by temperature variations, leading to inefficiencies in forming a standing wave and reducing image quality.
Innovation Solution
A variable focal length lens device with a resonance-lock controller that automatically tunes the drive signal frequency to the peak resonance frequency of the lens system, and a resonance-lock operation unit that temporarily suspends this tuning during image detection to stabilize the focal length and enhance image accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resonance-lock controller continuously tunes the drive signal frequency to track resonance frequency changes, then the standing wave formation efficiency is improved, but the image detection accuracy deteriorates due to frequency instability during capture
Solution Approach 1:
The resonance-lock controller operates periodically rather than continuously - it activates before image detection to tune the drive signal frequency to resonance, then suspends operation during image capture to maintain frequency stability. This periodic activation pattern resolves the contradiction by providing frequency tracking only when needed for standing wave formation, while ensuring frequency stability during the critical image detection phase.
Solution Approach 2:
The resonance-lock controller performs frequency tuning as a preliminary action before image detection begins. By completing the frequency adjustment and locking operations in advance, the system ensures that the drive signal is properly tuned to resonance frequency for efficient standing wave formation, then maintains that locked state without further adjustments during image capture, thereby preserving both efficiency and accuracy.
2Adaptability or versatility
If the drive signal frequency is continuously adjusted to compensate for temperature variations, then the resonance frequency tracking is improved, but the focal length stability deteriorates during image capture
Solution Approach 1:
The frequency adjustment operation is applied periodically before image capture rather than continuously during capture. This allows the system to adapt to temperature variations by retuning the drive signal frequency to match the current resonance frequency, then maintains that frequency setting stable throughout the image capture process, thereby achieving both adaptability and stability.
Solution Approach 2:
Temperature compensation through frequency adjustment is performed as a preliminary step before image detection. The system measures or estimates the resonance frequency shift due to temperature, adjusts the drive signal frequency accordingly, and then holds this adjusted frequency constant during image capture, ensuring both accurate tracking and stable focal length.
3Adaptability or versatility
If the resonance-lock controller remains active during image detection, then the frequency tracking capability is maintained, but the standing wave destabilizes and reduces image quality
Solution Approach 1:
The resonance-lock controller is designed to activate periodically before image detection and then suspend its active tuning function during the actual image capture. This periodic operation pattern allows the system to maintain frequency tracking capability when needed while preventing frequency fluctuations during image capture, thereby preserving both adaptability and image quality.
Solution Approach 2:
Frequency tracking and adjustment operations are completed as preliminary steps before image detection begins. By the time image capture starts, the drive signal frequency has already been tuned to match the resonance frequency and locked in place. The controller remains inactive during capture to prevent any frequency changes, ensuring stable standing wave formation and high image quality while maintaining the capability to retune between capture cycles.
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
This solution allows for efficient formation of a standing wave and improves the accuracy of images obtained by maintaining a constant frequency during image detection, preventing destabilization of the standing wave and ensuring high-quality image capture.
Implementation Method 1
a cylindrical oscillator made of a piezoelectric material that is immersed in a transparent liquid. When an alternating-current (AC) voltage is applied to an inner circumferential surface and an outer circumferential surface of the oscillator of the lens system, the oscillator expands and contracts in a thickness direction thereof to oscillate the liquid inside the oscillator
Implementation Method 2
when the frequency of the applied AC voltage is tuned to an intrinsic frequency of the liquid, a concentric standing wave is created in the liquid to form concentric regions of different refractive indexes around a center axis of the oscillator
Implementation Method 3
when light is introduced into the oscillator of the lens system along the center axis of the oscillator, the light follows a diverging or converging path depending on the refractive index of each of the concentric regions
Implementation Method 4
the variable focal length lens device includes the above-described lens system and a focusing objective lens (e.g. a typical convex lens or lens group), which are disposed on a common optical axis
Data Source
AI summary
A variable focal length lens device includes: a lens system whose refractive index changes depending on an inputted drive signal; an objective lens disposed in an optical axis common to the lens system; an image detector for detecting an image of a target object through the lens system and the objective lens; a resonance-lock controller for locking the frequency of the drive signal to a resonance frequency of the lens system; and a resonance-lock operation unit for switching enabling and suspending the resonance-lock controller.