Magnetic Detent Shutter Blade Retention

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Solution Overview

Problem

Stepper motor-driven optical shutters face challenges in retaining the shutter blade in a non-detent position when de-energized, leading to energy wastage and potential damage from continuous power application, and require additional components for mechanical holding, which increases cost and wear.

Innovation Solution

A magnetic detent system using a movable and stationary member with magnetic attraction to hold the shutter blade in place when the stepper motor is de-energized, providing a retention torque that exceeds the inherent detent torque of the stepper motor but is less than the driving force, allowing for precise positioning without continuous power application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous power is applied to maintain shutter blade position, then the shutter blade remains in the desired position, but energy is wasted and the motor may be damaged

Engineering Contradiction:

Improveshutter blade position stabilityVSAvoidcontinuous power consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies periodic action by using a magnetic detent mechanism that provides intermittent holding force at specific positions rather than continuous power. The magnetic detent engages periodically at predetermined positions to hold the shutter blade, eliminating the need for continuous motor power while maintaining position stability.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The magnetic detent mechanism provides self-service by automatically holding the shutter blade at predetermined positions without requiring external power. The system uses its own magnetic field to maintain position, making the holding function self-sufficient and independent of continuous electrical power supply.

Inventive Principle:

Principle #25Self-service

2Reliability

If additional mechanical holding components are added to retain shutter blade position, then position retention is improved, but device complexity and wear increase

Engineering Contradiction:

Improveshutter blade position retentionVSAvoidnumber of mechanical components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the holding function into the existing magnetic detent mechanism of the stepper motor. Instead of adding separate mechanical holding components, the solution combines the positioning and holding functions into a single integrated magnetic field system, reducing overall device complexity while maintaining retention capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces mechanical holding components with a magnetic field-based detent mechanism. The magnetic field substitutes for traditional mechanical springs, cams, or latches that would otherwise be needed to hold the shutter blade position, reducing mechanical complexity and wear.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If hard stops are used to define shutter blade positions, then positioning is achieved, but wear and potential damage occur

Engineering Contradiction:

Improveshutter blade position accuracyVSAvoidimpact and wear from hard stops

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical hard stops with a magnetic field-based positioning system. The magnetic detent provides positional reference without physical contact, substituting the mechanical impact-based stopping mechanism with a field-based holding mechanism that eliminates wear and impact damage.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetic detent mechanism provides beforehand cushioning by creating a magnetic field that gradually decelerates and holds the shutter blade before it reaches the mechanical limit. This prevents hard impacts by using magnetic forces to cushion the approach and maintain position without violent stopping.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

This solution enables efficient energy use by eliminating the need for continuous power to maintain the shutter blade in position, reducing wear and increasing the reliability and lifespan of the shutter system, while allowing for precise control of the shutter blade's position without hard stops, suitable for power-sensitive applications.

Implementation Method 1

a magnetic detent system using a movable and stationary member with magnetic attraction to hold the shutter blade in place when the stepper motor is de-energized

Methodology Applied

Scientific EffectMagnetic attraction: Magnetism

Data Source

PatentUS8956059B1Shutter with power-free magnetic detent

Publication Date: 2015.02.17 MELLES GRIOT INC

AI summary

An optical shutter apparatus has a shutter blade pivotable between first and second positions. The shutter blade in the first position blocks at least a portion of a light path. A stepper motor pivots the shutter blade to first or second positions. A magnetic shutter blade retention apparatus has a first movable member with a first surface, coupled to the shutter blade. A first stationary member is spaced apart from the shutter blade and is magnetically attracted to the first stationary member when the stepper motor is de-energized. When the shutter blade is pivoted to the first position, a point on the first surface is spaced apart from the first stationary member by a first distance; when the shutter blade is pivoted to the second position, the point on the first surface is spaced apart from the first stationary member by a second distance that is less than the first.