Lens Temperature Estimation via Multi-Position Thermal Change Rates

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Solution Overview

Problem

Existing methods for estimating the temperature of a lens in a lens apparatus are inaccurate due to relying solely on temperature differences between members, which can lead to time delays in temperature transfer and subsequent focus deviation corrections.

Innovation Solution

A lens apparatus equipped with temperature detectors at multiple positions and a processor that calculates the temperature change rate over time to estimate the lens temperature, using temperature correction coefficients to improve accuracy and enable timely focus deviation corrections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If temperature estimation is based solely on temperature difference between members, then the estimation method is simple, but the estimation accuracy deteriorates due to time delay in temperature transfer

Engineering Contradiction:

Improveestimation method complexityVSAvoidtemperature estimation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The invention changes the parameter used for temperature estimation from static temperature difference to dynamic temperature change rate. By calculating the rate of temperature change over time at multiple positions and using correction coefficients, the system captures the temporal dynamics of heat transfer, thereby improving estimation accuracy without excessive complexity increase

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system implements feedback by continuously monitoring temperature changes at multiple positions and using the calculated temperature change rates to estimate the lens temperature. The correction coefficients provide a feedback mechanism that adjusts the estimation based on the thermal behavior patterns observed at different positions within the lens barrel

Inventive Principle:

Principle #23Feedback

2Measurement precision

If temperature detectors are placed at multiple positions, then the temperature estimation accuracy is improved, but the device complexity increases

Engineering Contradiction:

Improvetemperature estimation accuracyVSAvoiddetector configuration complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The invention segments the temperature measurement task by placing detectors at multiple distinct positions within the lens barrel (such as near the front lens group, rear lens group, and intermediate positions). Each detector monitors the thermal state of a specific region, and the processor integrates these segmented measurements to achieve comprehensive temperature estimation of the lens

Inventive Principle:

Principle #1Segmentation

3Reliability

If temperature change rate calculation is used for estimation, then the focus deviation correction accuracy is improved, but the processing complexity increases

Engineering Contradiction:

Improvefocus deviation correction accuracyVSAvoidprocessing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary action by pre-calculating and storing temperature correction coefficients that relate temperature change rates at different positions to the actual lens temperature. When temperature measurement is needed, the processor simply retrieves these pre-established relationships and applies them to the current measurements, reducing real-time processing complexity while maintaining high correction accuracy

Inventive Principle:

Principle #10Preliminary action

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 allows for precise temperature estimation and correction of focus deviation, enhancing the accuracy and efficiency of focus adjustments in response to environmental temperature changes.

Implementation Method 1

detectors configured to detect temperatures at a plurality of mutually different positions of the lens apparatus, respectively

Methodology Applied

Scientific EffectTemperature detection:

Implementation Method 2

obtain a change amount of a temperature per unit time with respect to each of the plurality of mutually different positions based on each of the detected temperatures and a time at which each of the detected temperatures is obtained

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11487074B2Lens apparatus, and method of estimating temperature of lens

Publication Date: 2022.11.01 CANON KK

AI summary

Provided is a lens apparatus including: a lens; detectors configured to detect temperatures at a plurality of mutually different positions of the lens apparatus, respectively; and a processor configured to obtain a change amount of a temperature per unit time with respect to each of the plurality of mutually different positions based on each of the detected temperatures and a time at which each of the detected temperatures is obtained, to estimate a temperature of the lens based on the change amount with respect to each of the plurality of mutually different positions.