Optoelectronic Sensor Focus Adjustment via Deformable Mirror
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optoelectronic sensors with high accuracy requirements face challenges in maintaining precise focus due to aging, temperature, and hysteresis effects when using liquid lenses, which are susceptible to vibrations and have limited aperture sizes, leading to displacement errors and reduced accuracy in applications like logistics automation and safety technology.
Innovation Solution
An optoelectronic sensor system that adjusts the focal length of an optical element using direct optical feedback to compensate for external influences, allowing for precise focus positioning without relying on the long-term stability of the optical element, and includes a liquid-filled cavity with a membrane that changes curvature in response to pressure changes, along with a reference element for evaluating the actual focal length and temperature compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If liquid lenses are used for focus adjustment, then mechanical movement is eliminated and response speed is improved, but the lens becomes susceptible to vibrations and impacts causing liquid mixing and emulsion formation
Solution Approach 1:
The patent replaces the mechanical liquid lens system with a deformable mirror that uses piezoelectric actuators to change the curvature of a reflective surface. This substitution eliminates the liquid mixing problem while maintaining fast electronic control, as the solid-state piezoelectric mechanism is not susceptible to vibration-induced mixing.
Solution Approach 2:
The patent introduces a feedback control system with a position sensor that continuously monitors the focal position and adjusts the deformable mirror accordingly. This intermediary control mechanism compensates for disturbances and maintains reliable focus positioning despite environmental vibrations.
2Volume of moving object
If liquid lenses are used for focus adjustment, then installation space is reduced, but control accuracy is compromised due to aging effects, temperature influences and hysteresis behavior
Solution Approach 1:
The patent implements a closed-loop feedback system where a position sensor continuously measures the actual focal position and feeds this information back to the control unit. The control unit compares the measured position with the desired position and adjusts the deformable mirror to eliminate any deviation, thereby compensating for hysteresis and temperature effects.
Solution Approach 2:
The system performs self-correction by automatically detecting and compensating for focus deviations through the feedback loop. The control unit continuously adjusts the deformable mirror based on real-time measurements, enabling the system to maintain accurate focus without external intervention despite environmental variations.
3Measurement precision
If conventional electromechanical lens adjustment is used, then focus position can be precisely adjusted, but installation space requirements increase and mechanical structure demands are high
Solution Approach 1:
The patent replaces the electromechanical lens adjustment mechanism with a deformable mirror system controlled by piezoelectric actuators. This substitution maintains precise focus adjustment capability while dramatically reducing the mechanical structure requirements and installation space, as the deformable mirror can be integrated into the existing optical path without additional moving components.
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 approach ensures stable and precise focus positioning, improving resolution and reducing the need for stringent mechanical stability, while being more resistant to vibrations and allowing larger aperture sizes compared to traditional liquid lenses.
Implementation Method 1
a membrane (32) which is designed to change its curvature when the pressure of the liquid in the cavity changes
Implementation Method 2
a liquid-filled cavity with a membrane that changes curvature in response to pressure changes
Data Source
Figure 1~2
Figure 3~4d
Figure 5~6
AI summary
The sensor (10) has a focal length adjustable lens (14) assigned to a light transmitter (12) e.g. semiconductor light source such as LED, and/or a light receiving element (22) and formed as liquid or gel lens. Focal length of the lens is adjusted by specification of a control parameter. A reference light receiving element (28) and an evaluation unit (30) are provided for the lens and evaluate the actual focal length of the lens. The reference light receiving element and the evaluation unit regulate the actual focal length to a reference value. An independent claim is also included for a method for focusing an optoelectronic sensor.