Optical Waveguide Skin Imaging Privacy via Total Internal Reflection
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Solution Overview
Problem
Light-based skin treatment devices face privacy concerns due to the presence of image sensors that can capture images of the environment when not in use, as they are designed to obtain images of the skin region being treated.
Innovation Solution
The device incorporates an optical waveguide with a treatment light receiving surface and an imaging light exit surface, utilizing total internal reflection to allow image capture of the skin region while preventing image capture of the environment by positioning the image sensor to receive light only from the imaging light exit surface, which is reflected internally when no skin is in contact, thus reducing privacy concerns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an image sensor is included in the treatment device to capture images of the skin region being treated, then the ability to observe and analyze treatment effects is improved, but privacy concerns arise because the image sensor can also capture images of the environment when not in use
Solution Approach 1:
The optical waveguide is segmented into distinct functional surfaces: a treatment light receiving surface, a treatment light exit window, and an imaging light exit surface. This segmentation allows the device to separate treatment functions from imaging functions, enabling the image sensor to capture only skin images through the dedicated imaging surface while blocking environmental views during treatment operation.
Solution Approach 2:
Different surfaces of the optical waveguide are assigned different optical properties and functions. The treatment light exit window is made optically transparent for treatment light transmission, while the imaging light exit surface is positioned and oriented to provide localized imaging capability only when skin is in contact, creating spatially differentiated functionality that addresses privacy concerns.
2Measurement precision
If the image sensor is positioned to capture images through the treatment light exit window, then skin imaging is enabled, but the image sensor will also capture environmental images when no skin is in contact with the device
Solution Approach 1:
The optical waveguide is pre-configured with an imaging light exit surface that is optically coupled to the image sensor before treatment begins. This preliminary optical configuration ensures that the image sensor can only receive light through the designated imaging surface, which is covered by skin during treatment, thereby preventing environmental image capture from the outset.
Solution Approach 2:
The optical waveguide acts as an intermediary between the skin region and the image sensor. It transmits light from the skin region to the image sensor through the imaging light exit surface while blocking direct line-of-sight to the environment, using the waveguide structure itself as a mediator that controls light paths.
3Device complexity
If the device structure is simplified without an optical waveguide, then device complexity is reduced, but the ability to prevent environmental image capture while maintaining skin imaging is lost
Solution Approach 1:
The optical waveguide serves multiple functions simultaneously: it guides treatment light from the treatment light source to the treatment light exit window, guides imaging light from the skin region to the imaging light exit surface, and structurally prevents environmental light from reaching the image sensor. This multi-functionality addresses privacy concerns without requiring separate components for each function.
Solution Approach 2:
The imaging light exit surface is positioned at a different spatial location and orientation relative to the treatment light exit window, creating a separate optical path dimension. This dimensional separation allows the image sensor to view only through the imaging surface when skin is in contact, while the treatment window provides treatment light output, resolving the privacy issue through spatial configuration.
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 the capture of images of the skin region during treatment without capturing the environment, enhancing user privacy and allowing for personalized treatment adjustments based on the obtained images.
Implementation Method 1
said imaging light exit surface is arranged with respect to the main surface to receive light reflected at the main surface by total internal reflection at positions where, during operation, no skin is in contact with the main surface; said image sensor is arranged to receive from the imaging light exit surface light which is guided by total internal reflection from the main surface towards the imaging light exit surface
Data Source
AI summary
According to the invention, there is provided a light-based skin treatment device comprising a treatment light source; a treatment light exit window via which, during operation, treatment light generated by the treatment light source is applied to skin of a user, wherein the treatment light exit window comprises an optically transparent material arranged to contact the skin during operation; and an imaging unit comprising an image sensor 5 arranged to generate an image of the skin during operation. The skin treatment device further comprises an optical waveguide comprising a treatment light receiving surface, an imaging light exit surface and a main surface, wherein said treatment light receiving surface is arranged to receive the treatment light so that the treatment light enters the waveguide at the treatment light receiving surface; said main surface comprises the treatment light exit 10 window and is arranged to transmit the treatment light so that the treatment light exits the waveguide at the treatment light exit window; said imaging light exit surface is arranged with respect to the main surface to receive light reflected at the main surface by total internal reflection at positions where, during operation, no skin is in contact with the main surface; said image sensor is arranged to receive from the imaging light exit surface light which is 15 guided by total internal reflection from the main surface towards the imaging light exit surface.