Endoscope Light Source Optical System Compact Design
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Solution Overview
Problem
Existing light source optical systems for endoscopes are bulky and suffer from inferior color reproduction due to wide angle of incidence on interference type color filters, making them incompatible with various viewing methods and limiting brightness.
Innovation Solution
A light source optical system comprising a collective optical system, a magnification conversion optical system, and a positive lens group, with specific focal length and refractive index conditions to reduce beam diameter and maintain a narrow angle of incidence, incorporating reflection and absorption type infrared cut filters, and a color wheel with multiple filters for improved brightness and color reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a typical light source optical system with color filters in the illumination path is used, then color reproduction can be controlled by altering filter characteristics, but the system becomes bulky and the angle of incidence on filters becomes wide causing inferior color reproduction
Solution Approach 1:
The color filters are mounted on the light guide surface itself, nesting the filtering function within the existing optical path structure. This eliminates the need for separate bulky filter assemblies while maintaining color reproduction control capability.
Solution Approach 2:
The patent transitions from a spatial arrangement where filters are placed in the illumination path (three-dimensional volume occupation) to a surface-mounted arrangement on the light guide (two-dimensional surface utilization), thereby reducing system volume while maintaining functionality.
2Ease of manufacture
If interference type color filters are used with wide angle of incidence, then filter manufacturing is simplified, but transmittance characteristics change causing wavelength shift and ripple to short wavelength side
Solution Approach 1:
The patent applies different optical characteristics to different regions: the light guide surface is designed with specific refractive index and surface properties that create a controlled angle of incidence for incident light, while the color filters are positioned to utilize this controlled geometry. This local optimization ensures narrow angle of incidence at the critical filter interface.
Solution Approach 2:
The patent changes the geometric parameters of the light guide and filter assembly to control the angle of incidence. By adjusting the light guide surface curvature, orientation, and the relative positioning of filters, the system maintains a narrow angle of incidence range, preventing wavelength shift and ripple in the transmittance characteristics.
3Volume of moving object
If the diameter of light beams on color filter surface is reduced to compact the system, then apparatus size decreases, but the angle of incidence becomes wider worsening color reproduction
Solution Approach 1:
The light guide is designed with a curved surface geometry that controls the propagation path of light. This curvature enables the system to reduce beam diameter on the filter surface while maintaining a narrow angle of incidence, as the curved surface guides light at controlled angles rather than allowing wide-angle divergence.
Solution Approach 2:
The patent employs composite optical structures combining the light guide material with specific refractive index properties and the color filter materials. This composite design allows optimization of both beam diameter control and angle of incidence characteristics simultaneously, achieving compact size without sacrificing color reproduction quality.
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 system achieves a compact design compatible with multiple viewing methods, enhances brightness, and maintains superior color reproduction by optimizing the focal lengths and refractive indices of optical components and using filters to control light incidence.
Implementation Method 1
a collective optical system for collecting light from the light source
Implementation Method 2
a magnification conversion optical system for reducing a pupil magnification
Implementation Method 3
a positive lens group for collecting light from said magnification conversion optical system
Implementation Method 4
a reflection type infrared cut filter... satisfies the following condition (4)
Implementation Method 5
an absorption type infrared cut filter... located with a filter surface lying in a direction vertical to an optical axis
Implementation Method 6
a color wheel with multiple filters for improved brightness and color reproduction
Data Source
Figure 1~3
Figure 4
Figure 5
AI summary
The invention relates to a light source optical system for endoscopes which is compatible with various viewing modes, prevents an associated light source apparatus from growing bulky, and makes sure brightness. The light source optical system comprises, in order from the light source 1, the collective optical system 2 for collecting light from the light source, the magnification conversion optical system 3 for reducing a pupil magnification, and the positive lens group 4 for collecting light from the magnification conversion optical system 3, and satisfies Condition (1) with respect to the principal point-to-point distance d of the collective optical system 2 and magnification conversion optical system 3, the rear focal length f2B of the collective optical system 2 and the front focal length f3F of the magnification conversion optical system 3.