Cemented Prism Optical Axis Shift Correction
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Solution Overview
Problem
Oblique-viewing endoscopes face challenges in directing the visual field effectively due to manufacturing errors and optical-axis shifts, leading to issues like vignetting and overlapping light beams, which are not adequately addressed by existing optical path deflecting prisms.
Innovation Solution
The optical path deflecting prism for endoscopes consists of cemented first and second prisms with specific polished surfaces and reflecting surfaces, where the first reflecting surface on a plane parallel plate is adjusted to correct optical-axis shifts and ensure optimal angles (14.5° ≤ A ≤ 23° and 62° ≤ B ≤ 66°) to prevent vignetting and overlapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional optical path deflecting prism is used, then the structure is simple, but manufacturing errors cause optical-axis shifts leading to vignetting and overlapping light beams
Solution Approach 1:
The optical path deflecting prism is divided into a first prism and a second prism that are cemented together. This segmentation allows independent manufacturing and adjustment of each prism, enabling correction of optical-axis shifts through relative angle adjustment while maintaining the overall deflection function.
Solution Approach 2:
The prism system incorporates adjustable reflecting surfaces that can be rotated to specific angles (first reflecting surface at 14.5°-23°, second reflecting surface at 62°-66°). This dynamic adjustability allows compensation for manufacturing errors and optimization of light beam paths, transforming a static fixed-angle prism into an adjustable system.
2Manufacturing precision
If the numerical aperture is increased to transmit thick light beams, then imaging quality improves, but vignetting and ghosting occur
Solution Approach 1:
The patent specifies precise angular parameters for the reflecting surfaces (first reflecting surface at 14.5°-23°, second reflecting surface at 62°-66°) to optimize light beam transmission. By carefully controlling these angular parameters, the system achieves high numerical aperture transmission while preventing vignetting and ghosting through proper light path geometry.
Solution Approach 2:
The patent addresses the harmful effects of high numerical aperture by using the cemented prism structure to redirect and organize light paths. The reflecting surfaces are positioned to convert potential harmful reflections into useful light path deflections, transforming what would be ghosting artifacts into controlled optical path redirection.
3Ease of manufacture
If the reflecting surfaces are fixed at standard angles, then manufacturing is easier, but optical-axis shifts due to manufacturing errors cannot be corrected
Solution Approach 1:
The reflecting surfaces are designed to be rotatable rather than fixed, allowing adjustment to specific angles (first reflecting surface at 14.5°-23°, second reflecting surface at 62°-66°). This rotational capability enables post-manufacturing adjustment to correct optical-axis shifts while maintaining ease of initial fabrication at standard angles.
Solution Approach 2:
The adjustable angle mechanism provides feedback for correcting manufacturing errors. By allowing rotation to specific calibrated angles, the system can detect and compensate for optical-axis shifts caused by manufacturing tolerances, creating a feedback loop that improves final alignment precision.
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 allows for high-quality optical path deflecting prisms and oblique-viewing endoscope optical systems that can transmit thick light beams with high numerical aperture without vignetting, ghosting, or flare, effectively addressing manufacturing errors and ensuring high-quality imaging.
Implementation Method 1
the first prism and the second prism are cemented
Implementation Method 2
a first reflecting surface reflects first time a light beam incident on the optical path deflecting prism for endoscope
Implementation Method 3
the first polished surface is perpendicular to an oblique direction and has a first light-beam incident surface for light incident on the optical path deflecting prism for endoscope
Data Source
AI summary
An optical path deflecting prism for endoscope which is used for observing an object in an oblique direction, includes a first prism and a second prism, and the first prism and the second prism are cemented. The first prism has a first polished surface and a second polished surface. The first reflecting surface is a mirror surface having a mirror coating applied to a polished surface of a flat plate, and is fixed by gluing to the fifth polished surface of the second prism upon adjusting an angle so as to correct an optical-axis shift which occurs due to a manufacturing error of the first prism and the second prism.