Microneedle Array Imaging via Angle-Controlled Parallel Light
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Solution Overview
Problem
Existing methods for imaging transparent or semitransparent microneedle arrays suffer from insufficient contrast, making accurate inspection challenging.
Innovation Solution
Irradiating the surface opposite to the microneedle array with parallel light at specific angles, ensuring the incident angle on the bottom surface is 90 - θ° or greater and the incident angle on the side surface is less than the critical angle, to create an image where only the tip portion of the microneedle is dark and the base portion and sheet are bright, enhancing contrast for high-accuracy inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If dark field illumination is used to image transparent or semitransparent microneedle arrays, then the imaging method can be implemented with simple equipment, but the contrast of the obtained image becomes insufficient
Solution Approach 1:
The patent changes the illumination parameters by specifying precise incident angles (incident angle onto the bottom surface of the microneedle is 90 - θ° or greater, and incident angle onto the side surface is less than the critical angle) to optimize light interaction with the microneedle structure, thereby achieving high contrast images of transparent or semitransparent microneedle arrays without requiring complex equipment modifications
2Illumination intensity
If illumination light is incident at angles that allow light propagation to the microneedle tip, then the microneedle structure can be illuminated, but the image contrast deteriorates due to light emission from the tip portion
Solution Approach 1:
Instead of illuminating the microneedle from the top (conventional approach), the patent illuminates from the bottom surface at specific angles, inverting the illumination direction to achieve total internal reflection at the side surface and prevent light from reaching the tip, thereby creating high contrast images where the tip appears dark against a bright background
3Illumination intensity
If the incident angle of light onto the side surface of the microneedle is greater than or equal to the critical angle, then total internal reflection occurs, but light is easily propagated to the tip of the microneedle
Solution Approach 1:
The patent precisely controls the illumination incident angle parameter, setting it to be less than the critical angle for the microneedle material, thereby preventing total internal reflection and blocking light propagation to the tip, which is essential for achieving high contrast imaging of transparent or semitransparent microneedle arrays
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 approach allows for high-accuracy inspection of microneedle arrays by achieving a high-contrast image, enabling precise evaluation of microneedle shape and structure.
Implementation Method 1
an incident angle of light onto the side surface of the microneedle is less than a critical angle
Implementation Method 2
the illumination light is radiated under conditions in which an incident angle of light onto the bottom surface of the microneedle is 90 - θ° or greater and an incident angle of light onto the side surface of the microneedle is less than a critical angle
Data Source
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AI summary
Provided are a microneedle array imaging device, a microneedle array imaging method, a microneedle array inspection device, and a microneedle array inspection method which enable inspection of a microneedle array with high accuracy based on an obtained image. A microneedle array 1 is imaged from a side of a surface on which microneedles 2 are arranged by irradiating a surface on a side opposite to the surface on which the microneedles 2 are arranged with parallel light as illumination light. At this time, the surface is irradiated with the illumination light under conditions in which an incident angle α of light onto a bottom surface 2a of the microneedle 2 is 90 - θ° or greater and an incident angle β of light onto a side surface 2b of the microneedle 2 is less than a critical angle γ. In this manner, a state in which almost no light is emitted from a tip portion of the microneedle 2 can be generated. As the result, an image in which only the tip portion of the microneedle 2 is dark and other portions, in other words, a base portion of the microneedle 2 and a portion of a sheet 3 are bright can be imaged.