Blade Drive Device with Intermediary Locking for Shutter Impact Resistance
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Solution Overview
Problem
Electromagnetic drive-type focal plane shutters in cameras face challenges in ensuring impact resistance while minimizing power consumption and size, as they may unexpectedly move due to drop impacts when power is off.
Innovation Solution
A blade drive device with a substrate, movable curtains, a locking mechanism, a pivotally movable blade position holding member, and a linkage lever that engages with the electromagnetic actuator, allowing for reduced load torque and miniaturization, and a biasing member to prevent unexpected curtain movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If electromagnetic actuator is used to drive FP shutter, then miniaturization and simplification are achieved, but impact resistance deteriorates as curtains may unexpectedly move during drop impacts
Solution Approach 1:
A blade position holding member is introduced as an intermediary between the electromagnetic actuator and the curtains. This holding member includes a locking portion that can lock the drive lever at the open position, preventing unexpected curtain movement during impacts while allowing normal electromagnetic actuation. The intermediary component isolates the curtains from impact forces while maintaining the benefits of electromagnetic driving.
2Reliability
If detent torque of electromagnetic actuator is increased to prevent curtain movement, then impact resistance is improved, but power consumption increases
Solution Approach 1:
The blade position holding member with locking portion acts as a mechanical safeguard that does not require additional power. The locking mechanism engages passively to prevent curtain movement during impacts, eliminating the need to increase detent torque and associated power consumption.
3Manufacturing precision
If blade position holding member is interlocked with rotation operation of electromagnetic actuator, then precise position control is achieved, but pivoting range becomes constrained and design flexibility is reduced
Solution Approach 1:
The locking function is extracted from the electromagnetic actuator's rotation operation. The blade position holding member operates independently with its own locking mechanism, allowing the electromagnetic actuator to maintain full rotational freedom while the holding member provides precise position control at specific points (open/closed positions). This separation enables both precise control and design flexibility.
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
The solution achieves miniaturization, reduced power consumption, and enhanced impact resistance by regulating curtain movement, ensuring the curtains remain open without increasing detent torque, thus enabling a quickened shutter operation and preventing curtain movement during impacts.
Implementation Method 1
an electromagnetic actuator that extends in the first direction, and that is configured to be rotatable around a second axis which is different from the first axis
Implementation Method 2
a linkage lever that connects the blade position holding member and the electromagnetic actuator to each other, and that causes the blade position holding member to pivot around the first axis in response to the rotation around the second axis of the electromagnetic actuator
Data Source
AI summary
There are provided a blade drive device and an optical instrument. The blade drive device includes a substrate that has an opening, a front curtain and a rear curtain that are movable along an opening surface of the opening so as to open and close the opening, a front curtain locking portion that interlocks with opening and closing operations of the front curtain, a rear curtain locking portion that interlocks with opening and closing operations of the rear curtain, a regulation lever that is configured to be pivotally movable around a lever axis, that enters an operation trajectory of the front curtain locking portion and the rear curtain locking portion, and that is capable of entry and escape between an entry position for regulating the movement of the front curtain and the rear curtain in a closing direction and an escape position escaped from the operation trajectory, a regulation electromagnetic actuator that is configured to be rotatable around a regulation axis, and a linkage lever that causes the regulation lever to pivot around the lever axis in response to the rotation around the regulation axis of the regulation electromagnetic actuator. The regulation lever and the linkage lever engage with each other while being provided with play in a circumferential direction around the regulation axis.