Endoscope Autofocus Control with Dual Drive Controllers
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Solution Overview
Problem
Endoscope systems face challenges with reduced depth of field due to increased pixel count, leading to potential failures in position detection devices caused by temperature and humidity, which can disrupt autofocus functionality during medical procedures.
Innovation Solution
An imaging device with a movable frame supported by a voice coil motor, a position detecting unit, and a control system that generates drive signals based on position signals to maintain focus, switching between drive controllers to ensure continuous operation even if the position signal becomes faulty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels in the imaging device is increased, then the image quality is improved, but the depth of field becomes smaller
Solution Approach 1:
The patent implements autofocus functionality by dynamically adjusting the position of the movable lens using a voice coil motor actuator. The lens position is continuously adjusted based on detection signals from position detection devices, allowing the system to maintain optimal focus for different object distances despite the reduced depth of field caused by high pixel count.
2Measurement precision
If a position detection device is used to control autofocus, then the focus accuracy is improved, but the reliability decreases due to electrical sensitivity and damage risk from temperature and humidity
Solution Approach 1:
The patent employs multiple position detection devices (including both contactless and contact-type sensors) and implements redundancy in the autofocus control system. The control unit can switch between different detection devices based on their operational status, providing a backup mechanism that cushions against failures due to temperature, humidity, or electrical damage.
Solution Approach 2:
The patent introduces a control unit that acts as an intermediary between the position detection devices and the voice coil motor actuator. This control unit processes detection signals, determines appropriate lens positions, and controls the actuator accordingly, isolating the vulnerable position detection devices from direct environmental stresses while maintaining focus accuracy.
3Extent of automation
If a drive unit for autofocus is provided, then the autofocus functionality is improved, but the system complexity increases
Solution Approach 1:
The patent designs the movable frame structure to serve multiple functions: it supports the movable lens group, provides pathways for signal wires, and accommodates the voice coil motor actuator. This multi-functional design reduces the need for separate components and simplifies the overall system structure despite the added autofocus functionality.
Solution Approach 2:
The patent combines the position detection devices, voice coil motor actuator, and control unit into an integrated autofocus system within the endoscope head. The control unit consolidates the processing of detection signals and control of the actuator, merging multiple functions into a single coordinated system that manages complexity through integration.
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 system maintains image quality and allows for uninterrupted medical procedures by controlling the movable frame using imaging signals when position detection fails, preventing an increase in system size and ensuring reliable autofocus.
Implementation Method 1
a voice coil motor including a magnet and a coil and configured to move the movable frame relative to the supporting frame in the predetermined direction
Implementation Method 2
an imaging device configured to conduct photoelectric conversion on light passed through the optical device to generate an imaging signal
Data Source
AI summary
An imaging device includes: an optical device; a movable frame configured to support and move the optical device in a predetermined direction; a supporting frame configured to support the movable frame; a voice coil motor configured to move the movable frame relative to the supporting frame in the predetermined direction; a position detecting unit configured to detect a position of the movable frame relative to the supporting frame and generate a position signal; a signal processing unit configured to generate a drive signal and determine whether the position signal is normal; an imaging device; an image processing unit; a first drive controller configured to drive the movable frame; a second drive controller configured to drive the movable frame; and a selector configured to select a drive controller that controls driving of the movable frame from the first drive controller and the second drive controller.