Lens Apparatus Focus Position Correction for Optical Characteristic Variations
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Solution Overview
Problem
Existing lens interchangeable camera systems face challenges in maintaining the relationship between focus position and object distance due to manufacturing errors, temperature changes, and variations in optical characteristics caused by filter insertion/ejection, leading to shifts in the cam locus and optical performance deviations.
Innovation Solution
A lens apparatus with a focus lens, driver, position detector, and controller that corrects the focus lens position to a predetermined optical characteristic, adjusts driving information, and instructs the driver to align the focus lens with the detected position and corrected information, ensuring accurate focusing across varying optical conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the focus position is determined based on designed values or stored information, then the focusing operation is simple, but the focus position deviates from the target object distance due to optical characteristic changes
Solution Approach 1:
The system uses a position detector to detect the actual focus lens position and feeds this information back to the control unit. The control unit then corrects the detected position to the position in predetermined optical characteristics, ensuring accurate focusing despite optical characteristic changes. This feedback mechanism resolves the contradiction by maintaining simplicity while improving accuracy through automatic correction.
Solution Approach 2:
The system changes the parameter representation by detecting the actual focus lens position and transforming it into a corrected position based on predetermined optical characteristics. This parameter transformation allows the system to account for optical characteristic changes without complicating the user operation, as the correction happens automatically in the control unit.
2Device complexity
If the cam locus is fixed based on design values, then the lens structure is simple, but the focus position shifts due to manufacturing errors, temperature changes, and filter insertion/ejection
Solution Approach 1:
The position detector continuously monitors the focus lens position and provides feedback to the control unit. The control unit compares the detected position with the predetermined optical characteristics and applies corrections accordingly. This feedback loop maintains reliability by compensating for manufacturing errors, temperature changes, and filter variations without requiring a complex adjustable lens structure.
Solution Approach 2:
The system performs self-correction by automatically detecting position deviations and adjusting the focus lens position based on predetermined characteristics. The control unit autonomously handles corrections for manufacturing errors and environmental changes, eliminating the need for complex manual adjustment mechanisms while maintaining focus position consistency.
3Productivity
If the focus position is not corrected for optical characteristic changes, then the system operation is simple, but the optical performance deteriorates due to cam locus shifts
Solution Approach 1:
The system efficiently maintains optical performance by implementing an automatic feedback correction mechanism. The position detector monitors focus lens position, and the control unit applies real-time corrections based on predetermined optical characteristics. This automated process maintains high optical performance without requiring manual intervention, thus preserving operational efficiency while ensuring precision.
Solution Approach 2:
The system replaces complex mechanical adjustment mechanisms with an automated control system that uses position detection and electronic correction. Instead of requiring physical recalibration for optical characteristic changes, the control unit electronically adjusts the focus lens position based on detected deviations, maintaining manufacturing precision while keeping the system operation simple and efficient.
Data Source
AI summary
A lens apparatus detachable from an image pickup apparatus includes a focus lens, a driver configured to drive the focus lens, a first position detector configured to detect a position of the focus lens, and a controller configured to correct the position of the focus lens detected by the first position detector to a position of the focus lens in a predetermined optical characteristic, to transmit a corrected position of the focus lens to the image pickup apparatus, to correct driving information of the focus lens in the predetermined characteristic received from the image pickup apparatus to driving information of the focus lens in a current optical characteristic, and to instruct the driver to drive the focus lens in accordance with the position of the focus lens detected by the first position detector and corrected driving information of the focus lens.