Liquid Lens Thermal Compensation for Stable Variable Focus
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Solution Overview
Problem
Conventional coordinate measuring machines (CMMs) face frequent mechanical stress and limited lifetime due to frequent probe changes, necessitating a flexible and adaptable probing system that can quickly adjust to varying measuring conditions without compromising precision.
Innovation Solution
Employing a variable focal length lens with an actuator, such as a voice coil or piezo, to dynamically adjust focal length based on controlling signals, combined with a thermal stabilization mechanism to maintain consistent power consumption and temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If frequent probe changes are performed to adapt to different measuring requirements, then adaptability to measuring conditions is improved, but mechanical stress and device wear increase
Solution Approach 1:
The patent implements a universal probe head that can perform multiple measuring functions by integrating different optical elements (lenses, prisms, mirrors) that can be selectively activated. This allows a single probe to adapt to various measuring requirements (different focal lengths, beam directions) without physical replacement, thereby maintaining reliability while improving adaptability.
Solution Approach 2:
The patent employs dynamic optical elements with variable focal length lenses that can be adjusted during measurement operations. This dynamic capability allows the probe to adapt to different measuring conditions in real-time without mechanical replacement, reducing wear and extending probe lifetime while maintaining versatility.
2Productivity
If variable focal length lens is used to rapidly adapt to measuring requirements, then productivity is improved, but temperature stability deteriorates
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the temperature of the variable focal length lens and adjusts the actuator power consumption accordingly. This closed-loop control compensates for thermal effects, maintaining optical stability while enabling rapid focal length changes for high-speed measurements.
Solution Approach 2:
The patent carefully controls the power consumption parameters of the actuator to minimize thermal generation during focal length adjustments. By optimizing the electrical parameters and using pulsed actuation when possible, the system achieves rapid adaptation while maintaining temperature stability.
3Productivity
If actuator power consumption is increased to improve focal length adjustment speed, then productivity is improved, but temperature-induced drift increases
Solution Approach 1:
The patent uses feedback control to monitor optical drift caused by thermal effects and compensates by adjusting the focal length setting. This allows the system to use higher power consumption for faster adjustment while maintaining measurement precision through real-time compensation of thermal drift.
Solution Approach 2:
The patent performs preliminary temperature compensation by predicting thermal effects based on actuator power consumption levels and pre-adjusting the focal length calibration. This preliminary action prevents measurement precision degradation before it occurs, enabling faster adjustment speeds.
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 rapid adaptation to measuring requirements, enhances precision, and extends the lifespan of probes by minimizing mechanical stress and temperature-induced drift, allowing for faster and more accurate measurements.
Implementation Method 1
The force may be generated by means of an actuator (e.g. voice coil or piezo) which applies defined pressure to the lens
Implementation Method 2
The force may be generated by means of an actuator (e.g. voice coil or piezo) which applies defined pressure to the lens
Implementation Method 3
a variable focal length lens (tunable lens) to provide variation of its focal length as a function of an applied controlling signal
Implementation Method 4
The focal length also depends on temperature... the focal length setting has to be compensated as a function of temperature
Data Source
AI summary
Optical assembly comprising a variable focal length lens assembly comprising a variable focal length lens and an actuating unit, wherein an energy absorption rate of energy absorbed by the variable focal length lens assembly depends on the applied controlling signal. The optical assembly comprises a controlling unit configured to control focal length settings of the variable focal length lens by providing respective controlling signals and to apply a default controlling signal for providing a default focal length and default energy absorption rate. The controlling unit provides a thermal stabilisation functionality, the thermal stabilisation functionality is defined by applying a varying controlling signal related to a varying focal length and applying a compensation controlling signal related to a compensating focal length.