Focal Plane Shutter Exposure Consistency via Sensor Feedback
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Solution Overview
Problem
Focal plane shutters in image pickup devices experience variations in exposure periods due to differences in actuator energization timing and movement speed, affecting image quality.
Innovation Solution
Incorporating leading-shutter and trailing-shutter sensors to detect specific positions, a drive control portion adjusts power supplied to the actuators based on approach movement periods to synchronize the movement of the shutters, ensuring consistent exposure times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If actuators are used to move leading and trailing shutters, then shutter movement is achieved, but variations in exposure period occur due to differences in energization timing and movement speed
Solution Approach 1:
The patent implements feedback control by detecting the actual movement time of shutters using sensors and comparing it with target values. The drive control portion calculates correction amounts based on detected approach movement periods and adjusts actuator power accordingly, creating a closed-loop control system that compensates for variations in shutter movement speed and timing
Solution Approach 2:
The patent dynamically changes the power supply parameters to actuators during shutter movement. By adjusting the power supplied to leading and trailing shutter actuators based on detected approach movement periods, the system optimizes shutter movement speed and timing to maintain consistent exposure periods across different operating conditions
2Reliability
If power is corrected based on approach movement periods, then exposure period consistency is improved, but device complexity increases due to additional sensors and control mechanisms
Solution Approach 1:
The patent uses feedback from sensors detecting shutter positions and movement times to automatically adjust actuator power. This closed-loop control reduces exposure period variations without requiring complex manual calibration or adjustment mechanisms, as the system self-corrects based on detected parameters
Solution Approach 2:
The drive control portion automatically calculates and applies correction amounts based on detected approach movement periods without external intervention. The system monitors its own performance and adjusts its operation accordingly, reducing the need for external control complexity while maintaining exposure consistency
Data Source
AI summary
An image pickup device includes: a focal plane shutter including: a board including an opening; a leading shutter and a trailing shutter moving to open and close the opening; a leading-shutter actuator and a trailing-shutter actuator respectively causing the leading shutter and the trailing shutter to move; a leading-shutter sensor detecting that the leading shutter passes through a first position; and a trailing-shutter sensor detecting that the trailing shutter passes through a second position, an image pickup element that light enters through the opening; and a drive control portion.