Optical Waveguide Hair Cutter with Wavelength-Shift Skin Detection
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Solution Overview
Problem
Laser-based hair cutting devices face safety issues due to the risk of light coupling into the skin, potentially causing burning or irritation, especially when encountering skin lesions or defects.
Innovation Solution
Incorporating an optical waveguide with spaced optical structures that reflect light at different wavelengths to function as both a cutting element and a sensor, allowing the device to detect objects in contact, adjusting laser power based on detected objects for safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cutting element is brought very close to the skin to achieve good shaving closeness, then the shaving effectiveness is improved, but the risk of light coupling into the skin and causing burning or irritation increases
Solution Approach 1:
The optical sensor detects skin contact before the laser cutting element is activated. The system performs preliminary detection of the cutting surface using optical structures that sense changes in light reflection or transmission when skin is detected, thereby preventing harmful laser exposure before it can occur
Solution Approach 2:
An optical sensor acts as an intermediary between the laser cutting element and the skin. This sensor detects skin contact through optical means (changes in light reflection, absorption, or transmission properties) and provides feedback to control the laser activation, serving as a protective mediator that prevents direct harmful interaction
2Reliability
If optical structures are added to the cutting element to enable sensor functionality, then the safety is improved, but the device complexity increases
Solution Approach 1:
The optical waveguide structure serves multiple functions: it guides the laser light for hair cutting, contains optical structures that function as sensors for skin detection, and provides the structural framework for the cutting element. This multi-functionality reduces the need for separate components and minimizes overall device complexity while maintaining safety functionality
Solution Approach 2:
The sensing and cutting functions are merged into a single integrated optical waveguide structure. The optical structures that enable sensing are incorporated directly into the waveguide that also delivers the cutting laser, combining multiple functions into one component rather than using separate sensor and cutter elements
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
Enhances safety by reducing the risk of skin damage through intelligent power adjustment of laser light based on detected contact, ensuring effective hair cutting while minimizing skin irritation.
Implementation Method 1
The optical waveguide includes a plurality of optical structures spaced along its length, the optical structures being configured to reflect light at one or more wavelengths
Implementation Method 2
A fibre optic is located on a shaving portion of the device that is positioned to receive the laser light from the laser light source at a proximal end, conduct the laser light from the proximal end toward a distal end
Implementation Method 3
a laser light source is provided that is configured to generate laser light having a wavelength selected to target a predetermined chromophore to effectively cut a hair shaft
Data Source
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AI summary
There is provided a cutting element for use in a hair cutting device. The cutting element comprises an optical waveguide having a sidewall, wherein a portion of the sidewall forms a cutting face for contacting hair. The optical waveguide includes a plurality of optical structures spaced along its length, the optical structures being configured to reflect light at one or more wavelengths. When broadband light is directed along the optical waveguide the optical waveguide is such that: if the cutting face of the optical waveguide is not in contact with a target object, then each of the plurality of optical structures reflects light having a first wavelength; and if the cutting face of the optical waveguide is in contact with a target object, then at least one of the optical structures reflects light having a second wavelength different to the first wavelength. A hair cutting device comprising the cutting element and a method of operating the hair cutting device are also provided.