Shutter Charging Device with Brake Member for Stable Timing
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Solution Overview
Problem
Conventional focal plane shutters with a normally-open function face challenges in maintaining stable charging time due to load variance and temperature fluctuations, leading to variations in the stop position of the drive train, which affects the frame rate during continuous capture.
Innovation Solution
A shutter charging device with a gear component and a brake member that operates to stop the drive gear at a predetermined timing, ensuring consistent charging time and improving frame rate by reducing variance in the stop position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a DC motor is used to block off the opening by the first curtain immediately prior to imaging, then the normally-open function is achieved, but load variance and temperature fluctuations cause variance in the stop position of the drive train
Solution Approach 1:
The patent employs a feedback mechanism where the stop position of the drive train is detected by a position detection means (such as a sensor or encoder), and this detected position is fed back to the control means. The control means then adjusts the drive amount of the DC motor based on this feedback to ensure the first curtain blocks the opening at the precise required position, compensating for load variance and temperature fluctuations.
Solution Approach 2:
The patent replaces a purely mechanical positioning system with an electromechanical control system. Instead of relying solely on mechanical stops and gears, the system uses a DC motor with electronic control means and position detection to achieve precise positioning, substituting mechanical precision requirements with electronic control and feedback.
2Reliability
If a time margin is provided to absorb variance in charging time, then stop position variance is tolerated, but the frame rate during continuous capture cannot be improved
Solution Approach 1:
By implementing feedback control, the system eliminates the need for time margins. The control means continuously monitors the actual stop position and adjusts the drive amount in real-time, ensuring consistent positioning without requiring additional time buffers between shots, thereby enabling higher frame rates.
Solution Approach 2:
The control means performs preliminary adjustment of the drive amount based on detected position variations before the actual imaging operation. This preliminary correction ensures that the first curtain is positioned accurately without requiring post-positioning time margins, allowing continuous capture at higher frame rates.
3Reliability
If the drive amount of the DC motor is adjusted to compensate for stop position variance, then charging time stability is improved, but complex control mechanisms are required
Solution Approach 1:
The patent uses a feedback control loop where the position detection means monitors the stop position and the control means automatically adjusts the DC motor drive amount accordingly. This closed-loop feedback system maintains charging time stability without requiring complex mechanical adjustment mechanisms, as the control is achieved through electronic feedback and motor control.
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 stabilizes the charging time and enhances the frame rate during continuous capture by ensuring precise control over the drive gear's stop position, minimizing the need for time delays and reducing variability.
Implementation Method 1
a brake member for stopping the drive gear, wherein the brake member operates so that the drive gear stops at a predetermined timing in one sequence
Data Source
AI summary
A shutter charging device for a focal plane shutter with which a stable charging time can be obtained and frame speed can be improved during continuous capture. A shutter charging device charges a focal plane shutter device comprising an opening and a first curtain blade and second curtain blade that can block off the opening. The shutter charging device comprises a charging member that drives the first curtain blade and the second curtain blade in a predetermined sequence, a gear component that includes a drive gear for driving the charging member one sequence by each rotation and transmits the rotation of a DC motor to the charging member, and a lock lever that stops the drive gear. The lock lever operates so as to stop the drive gear at a predetermined timing within one sequence.