Cam-Driven Shutter Controller for High Frame Rate Imaging
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Solution Overview
Problem
Conventional focal plane shutters face challenges in increasing frame rate due to long motor idling sections required for overrun, which hinder continuous imaging and reduce camera efficiency.
Innovation Solution
The image pickup apparatus incorporates a controller-driven cam member with distinct phases to manage the drive members' operation, allowing for efficient transition between imaging states by adjusting motor direction and reducing the cam gear's overrun angle, thus shortening the time needed to pass through critical phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sufficient motor idling section is provided at the cam top to secure the overcharge state when the motor overruns the longest distance, then the reliability of the overcharge state is improved, but the time to pass through the cam top section increases and the frame rate decreases
Solution Approach 1:
The patent applies dynamics by making the motor operation flexible - the motor is stopped at the cam top during normal operation to ensure reliable overcharge state, but continues rotating through the cam top during continuous imaging mode. This dynamic adjustment of motor stopping behavior based on operational context resolves the contradiction between reliability and productivity.
Solution Approach 2:
The patent implements periodic action by alternating between two operational modes: normal mode where the motor stops at the cam top for reliable overcharge, and continuous mode where the motor keeps rotating through the cam top to maintain high frame rate. The system periodically switches between these modes based on imaging requirements.
2Reliability
If the motor is stopped at the cam top to ensure overcharge state, then the overcharge reliability is improved, but the time for continuous imaging increases
Solution Approach 1:
The system dynamically adjusts motor behavior based on the imaging mode. In continuous imaging mode, the motor continues rotating through the cam top without stopping, eliminating the time loss associated with stopping and restarting while maintaining sufficient charge through the cam's geometric design and controlled rotation speed.
Solution Approach 2:
The patent changes the operational parameters of the motor - specifically whether it stops or continues rotating - based on the imaging mode. This parameter change allows the system to optimize for either reliability or speed depending on the operational context, resolving the time loss issue in continuous imaging.
3Productivity
If the cam gear's overrun angle is reduced to shorten the time to pass through critical phases, then the frame rate is improved, but the motor control precision requirement increases
Solution Approach 1:
The cam mechanism serves as an intermediary that translates motor rotation into precise blade unit positioning. By using the cam's geometric profile to control the drive members, the system achieves precise control with a larger overrun angle, reducing the direct burden on motor control precision while maintaining high frame rate capability.
Data Source
AI summary
An image pickup apparatus configured to capture an image in accordance with a capturing instruction from a user includes a cam member having a first phase configured to hold the second drive member while the second biasing member is charged, and a second phase configured to enable the second drive member to be driven, a driver configured to drive the cam member, and a controller configured to drive the driver in a first direction after first imaging, until the cam member passes through the first phase and reaches the second phase, and to drive the driver in a second direction opposite to the first direction when an imaging instruction is released from the first imaging to second imaging next to the first imaging, until the cam member reaches the first phase from the second phase.