Angle-Selective Optical Element for Stereo Endoscope Ghost Image Reduction
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Solution Overview
Problem
Stereo video endoscopes with a fixed lateral viewing direction suffer from ghost images and flare issues due to quadruple reflections in the deflection prism group, which are undesirable and affect image quality.
Innovation Solution
Incorporating an angle-selective optical element with a surface coated by an incidence-angle-selective dielectric coating that restricts light bundles entering at large angles, preventing them from causing reflections and ghost images by ensuring only light within the field of view passes through, utilizing a multilayer or microprism structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a deflection prism group with multiple prisms is used to achieve lateral viewing direction, then the viewing direction is correctly established, but quadruple reflections occur causing ghost images and flare
Solution Approach 1:
An angle-selective optical element is introduced as an intermediary component between the entrance lens and the deflection prism group. This element selectively transmits light bundles within the field of view while reflecting peripheral light bundles, thereby preventing the quadruple reflections that cause ghost images and flare before the light enters the prism system.
Solution Approach 2:
The angle-selective optical element applies different optical properties to different regions of the light bundle. It allows light within the specific field of view angle to pass through while reflecting light at larger angles, creating a spatially selective transmission characteristic that addresses the ghost image problem without affecting the intended viewing function.
2Area of stationary object
If peripheral light bundles are allowed to enter the optical system, then the field of view is maximized, but reflections and ghost images are generated
Solution Approach 1:
The angle-selective optical element changes the transmission parameter of light bundles based on their angle of incidence. Light bundles within the field of view angle experience high transmission, while peripheral light bundles at larger angles experience reflection. This parameter-based selection maintains the effective field of view while eliminating the harmful peripheral light that causes ghost images.
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 effectively reduces ghost images and flare issues by selectively reflecting peripheral light bundles, maintaining image quality and minimizing distortions, thereby enhancing the stereo video endoscope's performance.
Implementation Method 1
a surface located in the beam path which is oriented perpendicular to the optical axis of the distal optical assembly. This surface is provided with an incidence-angle-selective dielectric coating
Implementation Method 2
incidence-angle-selective dielectric coating
Data Source
AI summary
An optical system for use with a stereo video endoscope with a fixed lateral viewing direction. The optical system including: a laterally-viewing distal optical assembly; and a proximal optical assembly, the distal optical assembly and proximal optical assembly jointly establishing a beam path, the proximal optical assembly including: a left channel lens system; and a right channel lens system similarly configured to the left channel lens system; wherein the distal optical assembly establishes an optical axis and is configured to couple incident light along the beam path from an object space into the left channel lens system and into the right channel lens system of the proximal optical assembly; and the optical system comprises an angle-selective optical element with a surface oriented perpendicular to the optical axis of the distal optical assembly, the surface being located in the beam path and coated with an incidence-angle-selective dielectric coating.