Endoscope Lightguide Geometry for Uniform Tip Illumination

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Solution Overview

Problem

Existing endoscopes face issues with non-optimal light distribution in the field of vision, leading to overexposure or underexposure of objects in the periphery and center, due to the wide-angle emission of light from LEDs and suboptimal lightguides or lens systems, which affect image quality.

Innovation Solution

The endoscope tip part incorporates a lightguide with a circumferential surface that reflects light internally, featuring a cross-section with strategically arranged corners and curvatures to ensure even illumination across the field of view, aligning with the aspect ratio of the image sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a regular cylindrical shape is used for the insertion portion, then it is easy to manufacture and insert, but it cannot be bent to observe curved body cavities

Engineering Contradiction:
Improveability to bend and observe curved body cavitiesVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The insertion portion is divided into multiple rigid sections connected by flexible portions, allowing the endoscope to bend while maintaining structural integrity. Each rigid section can be manufactured separately and assembled, resolving the contradiction between bendability and manufacturing ease.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flexible portion is constructed with multiple layers of tubes nested within each other, with reinforcement ribs positioned at specific angles. This nested structure enables bending capability while maintaining a compact form factor and relatively simple manufacturing process.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Object-affected harmful factors

If the distal end is made small for minimal invasiveness, then patient trauma is reduced, but the diameter of the light guide must be reduced limiting illumination

Engineering Contradiction:
Improvepatient traumaVSAvoidlight guide diameter and illumination
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The light guide utilizes a composite structure combining resin material with embedded optical fibers or reflective elements. This allows the light guide to maintain a small outer diameter for minimal invasiveness while incorporating sufficient optical components to provide adequate illumination intensity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Instead of increasing light guide diameter in one dimension, the patent uses multiple thin light guides arranged in a two-dimensional array at the distal end. This provides sufficient total illumination area while keeping each individual light guide diameter small for minimal patient trauma.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If rigid sections are connected by flexible portions, then the endoscope can bend to follow body cavities, but joint portions become vulnerable to bacterial adhesion and biofilm formation

Engineering Contradiction:
Improveability to bendVSAvoidbacterial adhesion and biofilm formation
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies hydrophobic coatings to the flexible portion that create surface energy differences, making it difficult for bacteria to adhere. The coating may exhibit contact angle changes or other surface property modifications that prevent bacterial colonization at the joint portions.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The flexible portion, which creates joints vulnerable to bacterial adhesion, is treated with hydrophobic coating that converts this vulnerability into an advantage. The coating creates a surface that actively repels bacteria, turning the joint portion from a high-risk area into a bacteria-resistant zone.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentEP4346540B1An endoscope
Publication Date: 2026.04.29 AMBU AS
  • EP4346540B1 patent drawingFigure 1~2
  • EP4346540B1 patent drawingFigure 3a~3c
  • EP4346540B1 patent drawingFigure 3d~3f

AI summary

An endoscope comprising a proximal handle and a distal tip with at least one transparent front window. The distal tip comprises an electronic image capture device having an essentially rectangular defining a vertical and horizontal imaging direction. A lightguide (13) is associated with the at least one light source arranged in alignment with a centre axis (A-A) of said lightguide (13). The lightguide (13) comprises a proximal end (14) and a distal end (16) and a circumferential surface (18) extending between said proximal end (14) and said distal end (16). The circumferential surface (18) is configured to provide total internal reflection of light emitted from the light source, and said circumferential surface defines cross-sections of said lightguide (13), wherein said cross-sections comprise four corners (15) arranged around said centre axis (A-A) so as to define four edges (21) subdividing the circumferential surface (18) into four side surfaces (18). The edges (21) extend with a predetermined angle with respect to the centre axis (A-A) and said side surfaces (18) have a curvature where the angle of the surface (18) with respect to the centre axis increases from the edges (21) towards the middle of the side surface.