Quadrangular Optical Guide for Uniform Laser Beam in Endoscope
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Solution Overview
Problem
Conventional laser endoscopes with bare fiber optical guides struggle to uniformly irradiate wide areas due to their circular cross-section, leading to insufficient intensity at the periphery and excessive intensity at the center, making it difficult to achieve effective hyperthermia with reduced endoscope diameter.
Innovation Solution
A laser therapeutic device using an optical guide element with a quadrangular cross-section within the endoscope probe tube, which converts the circular laser beam into a top-hat type beam of uniform intensity, allowing for wider area treatment while minimizing the endoscope's diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a bare fiber with circular cross section is used for guiding laser beam, then the structure is simple, but the beam intensity is non-uniform (bell shape) and the effective irradiation area is limited to the central portion
Solution Approach 1:
The patent changes the geometric parameter of the optical guide element from circular cross-section to quadrangular cross-section. This parameter change transforms the laser beam profile from a bell shape to a top-hat type with uniform intensity distribution, thereby resolving the contradiction between structural simplicity and beam intensity uniformity.
Solution Approach 2:
The patent introduces asymmetry by using a quadrangular cross-section instead of a symmetric circular cross-section. This asymmetric geometry modifies the laser beam propagation characteristics to achieve uniform intensity distribution across the beam cross-section, solving the intensity uniformity problem while maintaining manufacturing feasibility.
2Illumination intensity
If the diameter of the optical fiber is increased to emit laser beam of uniform intensity over wide area, then the beam intensity uniformity is improved, but the diameter of the whole laser endoscope increases causing greater burden on patients and poor operability
Solution Approach 1:
The patent changes the cross-sectional shape parameter of the optical guide element to quadrangular, which enables uniform beam intensity distribution without increasing the fiber diameter. This parameter change allows achieving wide area uniform irradiation while maintaining a small endoscope diameter, thus resolving the contradiction between beam uniformity and endoscope size.
3Length of stationary object
If the endoscope diameter is reduced to alleviate patient burden, then the operability and patient comfort are improved, but the ability to uniformly irradiate wide area with laser is compromised
Solution Approach 1:
The patent changes the optical guide element cross-section to quadrangular, which maximizes the irradiation area coverage for a given fiber diameter. This parameter change enables the endoscope to uniformly irradiate wide areas even with reduced diameter, resolving the contradiction between endoscope size and irradiation coverage.
4Area of stationary object
If a quadrangular cross section optical guide element is used to achieve uniform beam intensity, then the irradiation area coverage is improved, but the device complexity increases
Solution Approach 1:
The patent implements a simple parameter change from circular to quadrangular cross-section of the optical guide element. This geometric modification achieves uniform beam intensity and wide area coverage without significantly increasing device complexity, as the quadrangular structure can be manufactured using standard optical fabrication processes.
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
Enables effective hyperthermia with uniform radiation over a wide area, reducing patient burden and improving operability by maintaining a smaller endoscope diameter and ensuring consistent laser intensity across the treatment area.
Implementation Method 1
an optical guide element having a quadrangular cross section arranged in the probe tube for guiding a laser beam emitted from the tip of the optical fiber toward a tip side of the probe tube
Implementation Method 2
irradiating the removed area with a laser beam of the laser endoscope
Implementation Method 3
The hyperthermia (thermal therapy for cancers) is a treatment which heats a tumor locally at a temperature of 42° C. or more for 30 to 60 minutes
Data Source
AI summary
A laser therapeutic device for a laser endoscope capable of relatively reducing the diameter of the endoscope while being capable of emitting a laser beam of a uniform intensity over a wide area is provided. An optical guide element (a square-shaped rod lens 15, a guide tube 2b) having a quadrangular cross section and guiding a therapeutic laser beam emitted from the tip of an optical fiber toward the tip side of a probe is used. On the tip side of a probe tube 2 being a barrel, using clearances C1 to C4 formed between the optical guide element and the inner circumferential surface of the probe tube, a camera unit 11 as imaging means and white-color LED units 12 and an ultraviolet LED unit 13 as illumination means are arranged.