Liquid Lens Temperature Drift Compensation via Thermal Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid lenses in vision systems experience undesirable temperature-induced drift, leading to changes in focal length and image blur, which existing compensation methods fail to accurately address due to limited calibration accuracy and time-consuming processes.
Innovation Solution
A system and method that utilize a processor to control the temperature of a liquid lens by energizing or de-energizing a heating element and applying a bias signal to maintain the lens within a predetermined temperature range, thereby reducing drift effects, and adjust the focal distance based on image sharpness analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a liquid lens is used in a vision system, then the focal length can be adjusted to focus images at varying distances, but temperature changes cause drift in focal length leading to image blur
Solution Approach 1:
The patent applies parameter changes by monitoring temperature variations and adjusting the bias signal to the liquid lens accordingly. The system changes the operating parameters (bias signal magnitude) in response to temperature changes to compensate for focal length drift, thereby maintaining stable focusing performance across different temperatures.
Solution Approach 2:
The patent implements feedback by using a temperature sensor to continuously monitor the liquid lens temperature and adjusting the bias signal based on this feedback. The processor receives temperature values and modifies the bias signal to counteract temperature-induced focal length changes, creating a closed-loop control system that maintains focal length stability.
2Reliability
If existing compensation methods are used to address temperature drift, then some focus adjustment can be achieved, but the calibration process is time-consuming and limited in accuracy
Solution Approach 1:
The patent applies self-service by enabling the liquid lens system to automatically compensate for temperature drift without requiring external calibration procedures. The system uses an on-chip temperature sensor and automated bias signal adjustment to self-correct focal length variations, eliminating the need for manual calibration and reducing time loss.
Solution Approach 2:
The patent implements preliminary action by continuously monitoring temperature and proactively adjusting the bias signal before significant focal length drift occurs. The system anticipates temperature-induced changes and pre-adjusts the bias signal to maintain focal length stability, rather than reacting after drift has occurred.
3Reliability
If a heating element is used to control liquid lens temperature, then temperature stability can be improved, but additional components and control complexity are introduced
Solution Approach 1:
The patent applies the intermediary principle by using a heating element as a mediator between the temperature sensor and the liquid lens. The heating element acts as an intermediate device that actively adjusts the liquid lens temperature based on sensor feedback, providing precise temperature control while adding manageable complexity through a well-defined thermal control architecture.
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 effectively maintains a consistent focal length and improves image sharpness by stabilizing the liquid lens temperature, reducing temperature-induced drift and enhancing the accuracy of image focusing across varying conditions.
Implementation Method 1
A processor can control the temperature of a liquid lens by energizing or de-energizing a heating element
Implementation Method 2
The interior of the tube is coated with a hydrophobic material, which causes the aqueous solution to form a hemispherical lens which can be adjusted by applying a DC voltage across the coating to decrease its water repellency in a process called electrowetting
Data Source
AI summary
Systems and methods reduce temperature induced drift effects on a liquid lens used in a vision system. A feedback loop receives a temperature value from a temperature sensor, and based on the received temperature value, controls a power to the heating element based on a difference between the measured temperature of the liquid lens and a predetermined control temperature to maintain the temperature value within a predetermined control temperature range to reduce the effects of drift. A processor can also control a bias signal applied to the lens or a lens actuator to control temperature variations and the associated induced drift effects. An image sharpness can also be determined over a series of images, alone or in combination with controlling the temperature of the liquid lens, to adjust a focal distance of the lens.