Endoscope Objective Lens Regions for White and NIR Focus Alignment
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Solution Overview
Problem
Existing endoscope optical systems struggle to simultaneously capture clear images of both surface and subsurface structures using white light and near-infrared light due to misalignment of focal points, making it difficult to observe blood vessels beneath mucosal surfaces.
Innovation Solution
An objective optical system with a predetermined lens having distinct refractive regions, where the second region has greater refractive power than the first, allows separate and simultaneous transmission of white and near-infrared light beams to correct chromatic aberration and align focal points for both light types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single optical system is used for both white light observation and near-infrared light observation, then the device complexity is reduced, but the measurement precision deteriorates due to misalignment of focal points for different wavelengths
Solution Approach 1:
The objective lens is designed with different refractive regions (first refractive region with first refractive index and second refractive region with second refractive index) to provide different optical properties for different wavelength ranges. This local differentiation of optical properties enables the lens to focus white light and near-infrared light at the same focal point, resolving the alignment issue while maintaining a single optical system structure.
Solution Approach 2:
The patent changes the refractive index parameter across different regions of the objective lens. By making the refractive index vary spatially (first refractive index in first region, second refractive index in second region), the optical system achieves wavelength-specific focusing characteristics that enable simultaneous sharp focus for both white light and near-infrared light observations.
2Illumination intensity
If white light is used for illumination, then the color reproducibility is improved, but the penetration depth deteriorates making it impossible to observe subsurface structures
Solution Approach 1:
The illumination system alternates between white light illumination and near-infrared light illumination in a periodic manner. During white light illumination, surface structures are observed with high color reproducibility. During near-infrared illumination, subsurface structures are observed with adequate penetration depth. This periodic switching enables both observation modes within a single integrated system.
Solution Approach 2:
The optical system is designed to perform multiple functions using a single objective lens and detector assembly. The same optical system can observe both surface structures (using white light) and subsurface structures (using near-infrared light), eliminating the need for separate observation systems and enabling comprehensive tissue characterization.
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 design ensures high color reproducibility and sufficient brightness in white light images while ensuring near-infrared images are aligned with white light images, facilitating clear observation of both surface and subsurface structures.
Implementation Method 1
the predetermined lens has a first refractive region including an optical axis and a second refractive region located outside the first refractive region, a refractive power of the second refractive region is greater than a refractive power of the first refractive region
Data Source
AI summary
An objective optical system includes a predetermined lens disposed near the pupil of the objective optical system. The predetermined lens has a first refractive region including an optical axis and a second refractive region located outside the first refractive region. The refractive power of the second refractive region is greater than the refractive power of the first refractive region. A light beam reaching an image plane includes a first light beam and a second light beam. The first light beam is a light beam transmitted through the first refractive region and includes at least one of a beam of white light and a beam of near-infrared light. The second light beam is a light beam transmitted through the second refractive region and includes only the beam of near-infrared light. A predetermined conditional expression (1) is satisfied.