Endoscope Illumination Lens with Concave Diffuser

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Solution Overview

Problem

Existing illumination optical systems for endoscopes are large, have limited light distribution angles, and suffer from poor transmission efficiency.

Innovation Solution

A compact illumination optical system with negative optical power, featuring a first lens surface with a concave surface and a light diffusion surface, optimized by satisfying specific conditional expressions to achieve a wide light distribution angle and high transmission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional illumination optical systems are used, then illumination function is provided, but the system size becomes large

Engineering Contradiction:

Improveillumination optical system sizeVSAvoidillumination performance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The first lens surface is segmented into functionally distinct regions: a central concave surface region for light gathering and collimation, and an outer light diffusion surface region for wide-angle scattering. This segmentation allows each region to optimize its specific function, achieving compact size while maintaining effective illumination performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the first lens surface are assigned different optical properties: the central concave region provides focusing power while the outer diffusing region provides scattering. This local differentiation of optical quality enables the compact lens design to achieve both size reduction and maintained illumination reliability.

Inventive Principle:

Principle #3Local quality

2Shape

If conventional illumination optical systems are used, then illumination function is provided, but the light distribution angle is limited

Engineering Contradiction:

Improvelight distribution angleVSAvoidoptical system structure

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The light diffusion surface is positioned in the outer region of the first lens surface to specifically enhance light scattering in oblique directions. This local quality assignment enables wide light distribution angle without requiring additional optical elements, thus avoiding increased device complexity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The concave surface at the center portion of the first lens surface utilizes curved geometry to gather and redirect light. This curvature design, combined with the diffusing surface, achieves wide light distribution angle while maintaining a simple single-lens structure.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Loss of energy

If conventional illumination optical systems are used, then illumination function is provided, but transmission efficiency is poor

Engineering Contradiction:

Improvelight transmission efficiencyVSAvoidoptical system size

Core Design Contradiction:

Loss of energyVSVolume of moving object

Solution Approach 1:

The first lens surface is divided into a central concave region for efficient light gathering and transmission, and an outer diffusing region that redirects light without significant loss. This segmentation optimizes the transmission efficiency while keeping the optical system compact.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The optical parameters of the first lens surface are optimized by introducing the concave curvature and diffusing properties. These parameter changes enhance light transmission efficiency by reducing losses at interfaces and improving light path control, all within a compact form factor.

Inventive Principle:

Principle #35Parameter changes

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 enables a small-sized illumination optical system with a wide light distribution angle and improved transmission efficiency, enhancing the performance of endoscope illumination.

Implementation Method 1

a first lens surface closest to the light guide includes a concave surface that is provided at a center portion thereof and a light diffusion surface that is provided outside the concave surface in a radial direction

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

a light diffusion surface that is provided outside the concave surface in a radial direction

Methodology Applied

Scientific EffectLight diffusion: Scattering

Data Source

PatentUS20250130416A1Illumination optical system and endoscope

Publication Date: 2025.04.24 FUJIFILM CORP

AI summary

An illumination optical system that is disposed at a distal end of a light guide of an endoscope, the illumination optical system including only two or less lenses as lenses, wherein: the illumination optical system has negative optical power as a whole, a first lens surface closest to the light guide includes a concave surface that is provided at a center portion thereof and a light diffusion surface that is provided outside the concave surface in a radial direction. The illumination optical system satisfies a predetermined conditional expression.