Endoscope Voice Coil Motor Position Correction

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Solution Overview

Problem

Existing endoscope apparatuses with voice coil motors face challenges in accurately controlling the position of movable lenses due to magnetic field leakage, leading to errors in focusing and zooming operations.

Innovation Solution

An endoscope apparatus equipped with a voice coil motor, a magnetic sensor, and a processor that uses correction information to accurately detect and correct the position of the magnet, allowing for precise control of lens movement through a drive control circuit, thereby minimizing the influence of magnetic field leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a voice coil motor is used to drive the movable lens, then focusing and zooming operations can be performed, but magnetic field leakage causes errors in position detection

Engineering Contradiction:

Improvefocusing and zooming operationVSAvoidposition detection accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

A magnetic sensor is introduced as an intermediary component to detect the magnetic field generated by the voice coil motor. This magnetic sensor provides indirect position information that is then used to calculate the actual lens position, compensating for the magnetic field leakage effects and improving position detection accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements feedback control by continuously monitoring the magnetic field through the magnetic sensor and using this information to correct position detection errors. The detected magnetic field data is fed back to calculate and adjust the lens position, ensuring accurate focusing and zooming operations despite magnetic field leakage.

Inventive Principle:

Principle #23Feedback

2Device complexity

If the magnet position is detected directly without correction, then the position detection circuit is simple, but magnetic field leakage leads to incorrect position signals

Engineering Contradiction:

Improveposition detection circuit complexityVSAvoidposition signal accuracy

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Correction information is pre-calculated and stored in advance to compensate for magnetic field leakage effects. This preliminary correction data is then applied during position detection to ensure accurate position signals without requiring complex real-time correction circuits.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system replaces direct mechanical position sensing with magnetic field-based detection using a magnetic sensor. This substitution allows for non-contact position measurement and enables the use of correction algorithms to improve accuracy without increasing mechanical complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enables high-precision control of lens position, improving focusing and zooming capabilities by accurately correcting for magnetic field influences, resulting in enhanced image quality and operational reliability.

Implementation Method 1

a voice coil motor provided in the endoscope and including a magnet and a coil such that the magnet is movable with respect to the coil

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

voice coil motor... including a magnet and a coil such that the magnet is movable with respect to the coil

Methodology Applied

Scientific EffectElectromagnetic interaction: Lorentz Force

Implementation Method 3

a magnetic sensor disposed in a vicinity of the coil and configured to detect a magnetic field of the magnet in order to detect a position of the magnet

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentUS11567288B2Endoscope apparatus

Publication Date: 2023.01.31 OLYMPUS CORPORATION(JP)

AI summary

An endoscope apparatus has an endoscope and a video processor. The endoscope has a magnet and a coil, the magnet has a voice coil motor configured to be movable with respect to the coil and a Hall device disposed in the vicinity of the coil and configured to detect a magnetic field of the magnet in order to detect a position of the magnet. The video processor includes a position detection circuit configured to detect the position of the magnet from an outputted signal of the Hall device, an arithmetic operation section configured to correct a sensor output signal indicating the position of the magnet detected by the position detection circuit using correction information and output the sensor output signal, and a drive control circuit configured to control a current or a voltage to the coil based on an arithmetic operation result of the arithmetic operation section.