Hemispheric Mirror LED Illumination for Endoscopy
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Solution Overview
Problem
Existing LED illumination systems for endoscopy face inefficiencies in optical fiber input volume compared to xenon lamps, with conventional LED systems achieving lower input volumes due to limited numerical aperture (NA) and light leakage issues.
Innovation Solution
The proposed LED illumination apparatus incorporates a planar and point-symmetrical LED with a hemispheric or plano convex mirror, where the LED's Lambert distribution light emission is reflected and focused to match the optical fiber's NA, optimizing the interval and aperture dimensions to enhance light incidence efficiency without altering the LED's output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If an LED with Lambert distribution is used to illuminate optical fiber, then the LED structure is simple and energy efficient, but the optical fiber input volume is small compared to xenon lamps
Solution Approach 1:
The patent employs a hemispheric mirror with a specific curvature radius to reflect and redirect LED light. The curved surface of the hemispheric mirror enables effective collection and redirection of Lambert-distributed light from the LED, increasing the numerical aperture and optical fiber input volume while maintaining energy efficiency
Solution Approach 2:
The patent optimizes specific parameters including the interval between LED and hemispheric mirror (t ≤ curvature radius), the aperture dimension of the hemispheric mirror, and the positioning of the optical fiber at the aperture center. These parameter optimizations maximize light coupling efficiency and increase optical fiber input volume
2Device complexity
If LED and optical fiber are abutted against each other, then the structure is simple, but light leakage occurs and incidence efficiency is low
Solution Approach 1:
The hemispheric mirror acts as an intermediary optical element between the LED and the optical fiber. It redirects light that would otherwise leak out, reflecting it back toward the optical fiber aperture and significantly reducing light loss
Solution Approach 2:
The hemispheric mirror creates a feedback mechanism where light escaping from the LED is reflected back into the system and redirected to the optical fiber, effectively recapturing energy that would be lost
3Quantity of substance
If a hemispheric mirror is used to increase LED luminance, then the optical fiber input volume increases, but the LED shape, layout, and focusing lens requirements become complex
Solution Approach 1:
The hemispheric mirror performs multiple functions simultaneously: it reflects light to increase numerical aperture, defines the aperture through its opening, and positions the optical fiber at its center. This multi-functionality reduces the need for separate focusing lenses and complex positioning mechanisms
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 increases the optical fiber input volume, approaching the efficiency of xenon lamps, with improved light guidance and reduced light leakage, thereby enhancing the LED illumination system's performance.
Implementation Method 1
the hemispheric mirror forms a reflection face on an interior face thereof... the reflection face is disposed so as to oppose to the LED
Data Source
AI summary
The present invention is characterized in that a light emitting part of LED 1 has a planar and point-symmetrical shape, a light emission angle distribution is a Lambert distribution and a light emission face is a scattering face; a hemispheric mirror 3 forms a reflection face 3a on the interior face, and has an aperture 3b at the center, while the reflection face 3a is disposed so as to oppose to LED 1; a normal line of LED 1 and an optical axis of the hemispheric mirror 3 are coincident with each other; an interval between LED 1 and the hemispheric mirror 3 is equal to or smaller than a curvature radius of the hemispheric mirror 3; a dimension of the aperture 3b of the hemispheric mirror 3 is substantially equal to a radiation dimension; and sin (tan−1 d LED/2t)≈NA object is established.