Lens Control Device Temperature Compensation
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Solution Overview
Problem
Conventional lens controlling devices using a photo reflector for lens position detection face challenges with temperature characteristics, leading to inaccurate lens positioning due to the need for additional light receiving elements for dark current measurement, increasing size and cost, or requiring dark current measurement when the photo reflector is not operating, which degrades temperature change handling and lens control accuracy.
Innovation Solution
A lens controlling device with a servo calculation section, motor driver, and temperature correction calculation section that generates a temperature correction signal to adjust the motor current setting value, allowing the lens to be driven to its target position independently of the photo reflector's temperature characteristics, using an integrator to improve feedback gain and correct either the target lens position or lens position detection signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photo reflector is used for lens position detection, then lens position can be detected, but temperature characteristics cause inaccurate positioning
Solution Approach 1:
The patent implements a feedback mechanism where the photo reflector continuously detects lens position, and the control circuit adjusts the drive current based on the detected position and temperature information. This closed-loop feedback system compensates for temperature-induced positioning errors by constantly correcting the lens position based on actual feedback signals.
Solution Approach 2:
The patent changes the operating parameters of the photo reflector by adjusting the drive current based on temperature conditions. The control circuit modifies the current supplied to the photo reflector to compensate for temperature effects, thereby maintaining accurate position detection across varying temperatures.
2Reliability
If additional light receiving elements are added to measure dark current, then temperature characteristic can be compensated, but device size and cost increase
Solution Approach 1:
The patent enables the photo reflector to self-compensate for temperature effects by using its own output signal characteristics. The control circuit analyzes the photo reflector's output to extract temperature information and adjusts the drive current accordingly, eliminating the need for separate dark current measurement elements.
Solution Approach 2:
The patent makes the photo reflector serve multiple functions: it detects lens position and simultaneously provides temperature information through its output signal characteristics. This multi-functionality eliminates the need for separate temperature sensing elements or dark current measurement circuits.
3Measurement precision
If dark current is measured when photo reflector is not operating, then temperature characteristic can be measured, but real-time temperature change accuracy is degraded
Solution Approach 1:
The patent maintains continuous operation of the photo reflector throughout the measurement and control process. The system continuously monitors the photo reflector's output signal to extract temperature information in real-time, ensuring that temperature compensation is always current and accurate without interruption or delay.
Solution Approach 2:
The patent performs preliminary analysis of the photo reflector's output signal characteristics to extract temperature information before actual positioning adjustments are needed. This allows the system to be prepared for temperature compensation in advance, maintaining real-time accuracy.
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 accurate lens positioning without relying on the photo reflector's temperature characteristics, reducing system size and cost, and enhancing the accuracy of lens control by compensating for temperature changes in real-time, while maintaining the ability to correct for hand-movement blurring.
Implementation Method 1
a photo reflector 2 which detects the position of the lens unit 1
Implementation Method 2
the temperature correction calculation section includes an integrator which integrates the motor current setting value
Data Source
AI summary
A lens controlling device disclosed herein includes: a servo calculation section which calculates a motor current setting value such that a lens position detection signal which is inputted from a photo reflector agrees with a predetermined target lens position setting signal; a motor driver which generates a motor current in accordance with the motor current setting value, and supplies the motor current to a lens drive motor; and a temperature correction calculation section which monitors the motor current setting value to generate the temperature correction signal, and corrects either one of the target lens position setting signal and the lens position detection signal.