Endoscope Lighting Optical Device Minimizing Light Loss
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Solution Overview
Problem
Existing endoscope designs experience light quantity loss and increased temperature at the distal portion due to blockage of illumination light rays, leading to reduced illumination efficiency and image quality degradation.
Innovation Solution
The endoscope incorporates a lighting optical device with a rod-like optical element and two lenses, where the optical element has a core with a lower refractive index clad, and a spacer ring is used to maintain distance between the lenses, ensuring that light rays from the peripheral portion of the exit surface travel parallel to the axis without obstruction, reducing light quantity loss and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat ray cut filter is used to prevent temperature rise of the distal portion, then temperature control is improved, but light quantity loss increases causing heat generation
Solution Approach 1:
The patent removes the heat ray cut filter from the optical path and instead uses the rod-like optical element with specific refractive index design to naturally separate and manage different wavelengths of light. The rod element extracts and guides visible light while allowing infrared heat rays to pass through or be separately managed, eliminating the need for the filter that caused light quantity loss.
Solution Approach 2:
The patent changes the refractive index parameters of the rod-like optical element to optimize light transmission characteristics. By carefully selecting the refractive index of the rod material and its coating layers, the system achieves efficient light guidance while minimizing heat generation from light quantity loss, without requiring additional filtering components.
2Manufacturing precision
If a spacer ring is disposed between the optical element and lens to determine distance, then optical alignment is improved, but light rays from peripheral portion are blocked causing light quantity loss
Solution Approach 1:
The patent transitions from using a spacer ring (one-dimensional spacing solution) to a rod-like optical element with radially extending light-guiding surfaces (three-dimensional structural solution). This dimensional change allows light rays from the peripheral portion to be naturally directed along the optical axis through the rod's geometry, eliminating blockage while maintaining precise optical alignment through the rod's inherent structural precision.
3Measurement precision
If higher pixel density is used in the image sensor, then image quality is improved, but power consumption increases causing heat generation
Solution Approach 1:
The patent converts the harmful effect of high power consumption and heat generation into a benefit by designing the rod-like optical element to efficiently guide light while minimizing losses. The optimized optical system reduces the total light power required for illumination, thereby reducing the heat load on the high-density image sensor and allowing it to operate more efficiently without compromising image 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
This configuration enhances illumination efficiency by minimizing light loss and reduces temperature rise at the distal portion, thereby improving image quality and reducing heat-related noise in the imaging signal.
Implementation Method 1
This optical element has a core surrounded with a clad to obtain a suitable light distribution property. A refractive index of a clad is lower than that of the core.
Implementation Method 2
In this lighting optical device, two plano-convex lenses are disposed with an appropriate space therebetween on an exit side of the optical element. Light rays, parallel with an optical axis of the illumination light, coming out of the light guide are converged in the lighting optical device and then spread to achieve required light distribution.
Data Source
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AI summary
A lighting optical device (20) is disposed in a distal portion (16a) of an endoscope (11), and illuminates a target with light transmitted through a light guide (27). An optical element (40) has an incident surface (40a) facing the light guide, an outer circumferential portion (46b) having light reflection function, and a convex exit surface (40b). In a lens mounting hole (38) formed in the distal portion, a lens (41) is housed in front of and at a predetermined distance away from the optical element fixed in a lens barrel (43). An outer diameter of the lens is greater than that of the optical element. To allow light rays, coming out of a peripheral portion of the exit surface of the optical element and traveling parallel with an optical axis, to be incident on the lens, a diameter of a space between the optical element and the lens is greater than or equal to the outer diameter of the optical element.