Resonance-Locked Liquid Lens Frequency Tuning
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Solution Overview
Problem
The variable focal length lens device faces challenges in maintaining efficient operation due to temperature-induced changes in the resonance frequency of the liquid lens system, leading to deviations in the drive signal from the peak resonance frequency, which affects the formation of a standing wave and the accuracy of image detection at desired focal lengths.
Innovation Solution
A variable focal length lens device is designed with a lens controller that includes a resonance-lock controller to automatically tune the drive signal frequency to the current resonance frequency of the lens system, and a lens operation unit that enables and suspends the resonance-lock control, allowing for precise adjustment of the drive signal frequency, amplitude, and maximum voltage, ensuring efficient formation of a standing wave and accurate image detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed frequency drive signal is used, then the device structure is simple, but the drive signal frequency deviates from the resonance frequency due to temperature changes, reducing the efficiency of standing wave formation
Solution Approach 1:
The patent implements a feedback control mechanism where the drive signal frequency is continuously adjusted based on the resonance frequency of the liquid lens system. The resonance frequency detection unit monitors the actual resonance frequency, and the frequency adjustment unit modifies the drive signal frequency to match it, ensuring efficient standing wave formation despite temperature variations.
Solution Approach 2:
The system automatically detects and adjusts its own operating parameters. The resonance frequency detection and frequency adjustment functions enable the system to self-correct for temperature-induced frequency shifts without external intervention, maintaining optimal performance autonomously.
2Reliability
If the drive signal frequency is manually adjusted, then the standing wave formation efficiency can be maintained, but the operation complexity and time consumption increase
Solution Approach 1:
The system automatically detects and adjusts its own operating parameters. The resonance frequency detection and frequency adjustment functions enable the system to self-correct for temperature-induced frequency shifts without external intervention, maintaining optimal performance autonomously.
Solution Approach 2:
The patent implements a feedback control mechanism where the drive signal frequency is continuously adjusted based on the resonance frequency of the liquid lens system. The resonance frequency detection unit monitors the actual resonance frequency, and the frequency adjustment unit modifies the drive signal frequency to match it, ensuring efficient standing wave formation despite temperature variations.
3Measurement precision
If the resonance-lock control is always enabled, then the frequency accuracy is maintained, but the device complexity and power consumption increase
Solution Approach 1:
The patent implements dynamic control where the resonance-lock function is selectively activated or deactivated based on operational requirements. The control unit can switch between automatic frequency tracking and fixed frequency operation modes, allowing the system to adapt its complexity level to the specific task at hand.
4Measurement precision
If the drive signal amplitude is increased to improve focus detection accuracy, then the image detection precision improves, but the energy consumption and heat generation increase
Solution Approach 1:
The patent optimizes the drive signal amplitude parameter to achieve the minimum necessary level for accurate image detection. By carefully selecting and adjusting the amplitude parameter, the system achieves sufficient detection precision while minimizing energy consumption and heat generation.
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 enables the lens device to maintain efficient image detection at desired focal lengths by automatically adjusting the drive signal to match the changing resonance frequency, ensuring consistent and accurate image capture across varying focal lengths.
Implementation Method 1
a cylindrical oscillator 32 made of a piezoelectric material that is immersed in a transparent liquid 35. 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 diffusing or converging path according to the refractive index of each of the concentric regions
Data Source
AI summary
A variable focal length lens device includes: a lens system whose refractive index is variable in response to an inputted drive signal; an image detector for detecting an image of a target object through the lens system; a lens controller for outputting the drive signal and an illumination signal; and a lens operation unit for adjusting a frequency and amplitude of the drive signal outputted by the lens controller and an image-detection timing for the image detector. The lens controller includes a resonance-lock controller for tuning the drive signal to a resonance frequency of the lens system. The lens operation unit includes a resonance-lock operation unit for switchably enabling and suspending the resonance-lock controller.