Endoscopic Camera Head Anti-Reflective Coating
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Solution Overview
Problem
Endoscopic devices face challenges in reducing flare and ghosting phenomena, which degrade image quality due to stray light reflections in the optical system, particularly in the camera head, where applying anti-reflective coatings on exposed components like the eyepiece lens and cover glass is impractical due to autoclaving processes and the use of sapphire glass with high reflectance.
Innovation Solution
An anti-reflective coating is applied to at least one face of the protective glass of the image sensor within the camera head, and the protective glass is either positioned at a specific distance or tilted relative to the light receiving face, in conjunction with a tilted cover glass, to minimize stray light reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If anti-reflective coatings are applied to exposed optical components like eyepiece lens and cover glass, then stray light reflections are reduced, but these components cannot be coated due to autoclaving processes and material constraints (sapphire glass with high reflectance)
Solution Approach 1:
The patent extracts the anti-reflective coating function from the exposed optical components (eyepiece lens and cover glass) and relocates it to the protective glass of the image sensor, which is not subjected to autoclaving and can be effectively coated
Solution Approach 2:
The patent changes the location parameter of where anti-reflective treatment is applied, moving from external optical components to the internal image sensor protective glass, thereby avoiding the autoclaving constraint
2Volume of moving object
If the protective glass is positioned close to the light receiving face, then the optical system is compact, but stray light reflections increase causing flare and ghosting
Solution Approach 1:
The patent applies different properties to different parts of the protective glass: an anti-reflective coating is applied to the outer surface while the inner surface remains close to the light receiving face, achieving both compactness and reduced reflections
Solution Approach 2:
The protective glass is combined with an anti-reflective coating material to create a composite structure that maintains compact dimensions while reducing stray light reflections through the coating's optical properties
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 configuration significantly reduces stray light intensity on the image sensor, thereby minimizing flare and ghosting, leading to improved image quality and the ability to capture higher-quality images.
Implementation Method 1
an anti-reflective coating is provided on at least one face of a protective glass disposed facing opposite a light receiving face configured to receive the observation light
Data Source
AI summary
There is provided a endoscopic camera head including a cover glass, provided on a connecting face that connects to a base of an endoscope, and disposed to cover an opening for taking into a housing observation light guided inside a lens barrel of the endoscope to the base, and an image sensor configured to receive the observation light passing through the cover glass and entering the housing, and capture an image of a target of observation. In the image sensor, an anti-reflective coating is provided on at least one face of a protective glass disposed facing opposite a light receiving face configured to receive the observation light.