A G-Fresnel Optical Device and Image Processing Based Miniature Spectrometer for Mechanoluminescence Sensor Applications

Abstract

This paper presents a miniature spectrometer fabricated based on a G-Fresnel optical device (i.e., diffraction grating and Fresnel lens) and operated by an image-processing algorithm, with an emphasis on the color space conversion in the range of visible light. The miniature spectrometer will be cost-effective and consists of a compact G-Fresnel optical device, which diffuses mixed visible light into the spectral image and a μ-processor platform embedded with an image-processing algorithm. The RGB color space commonly used in the image signal from a complementary metal–oxide–semiconductor (CMOS)-type image sensor is converted into the HSV color space, which is one of the most common methods to express color as a numeric value using hue (H), saturation (S), and value (V) via the color space conversion algorithm. Because the HSV color space has the advantages of expressing not only the three primary colors of light as the H but also its intensity as the V, it was possible to obtain both the wavelength and intensity information of the visible light from its spectral image. This miniature spectrometer yielded nonlinear sensitivity of hue in terms of wavelength. In this study, we introduce the potential of the G-Fresnel optical device, which is a miniature spectrometer, and demonstrated by measurement of the mechanoluminescence (ML) spectrum as a proof of concept.

Fabrication of Tapered 3D Microstructure Arrays Using Dual-Exposure Lithography (DEL)

“…MSAs are in high demand in optics and photonics, as their optical properties can be tuned through microstructures geometry [ 10 , 61 , 62 , 63 ]. PDMS elastomer-based gratings are particularly popular for their advantages (e.g., UV-vis transparent, cost-effective, consistent, and chemically stable), and thus used in many biomedical applications (e.g., thermal detectors [ 19 ], glucose monitoring devices [ 62 ], cell interaction [ 20 ], microfluidics [ 13 ], and spectrophotometers [ 64 ]). Hence, we tested the ability of our PDMS DEL-MSAs as a transmission-phase grating as it has unique surface properties.…”

The Study of Aviation Safe Incapacitating Device Based on LED Technology with a Smart-Illumination Sensor Unit

“…Similar to luminous flux modification is a TIR (total internal reflection), which combines the advantages of reflectors and lens used to reach for maximum efficiency in Figure 4 d. The central beams are directed by primary and secondary lens and the reflector directs other beams. The lens principle is convenient for applications requiring a narrow and high intensity beam with small requirements to power consumption [ 22 , 23 , 24 , 25 , 26 , 27 ].…”

3D‐Printed Holographic Fresnel Lenses

“…This hybrid and straightforward fabrication process provides more control over lens geometry, least production time, and eliminates plasma treatments compared to the sandwich molding of the G‐Fresnel lens. [ 40 ] This work opens the possibilities of designing and fabricating normal and holographic (micropatterned) Fresnel lenses using the masked stereolithography (MSLA)‐based additive manufacturing technology. The fabrication of such multifunctional lenses is vital in developing miniature spectrometers where the visible light is converted into a spectral image by an image‐processing algorithm.…”

“…Fresnel lenses have a myriad of applications in condenser optics, field lenses, and magnifiers. [38] Moreover, light collimators, [21] smartphone and miniature spectrometers, [39,40] photovoltaic panels, [41][42][43] focusing elements in ultrasonic devices, [44] automobiles headlights, [45] nanophotonic devices, [43] medical diagnostic imaging devices, [46] and plasmonic lensing [47,48] are some examples of the optical devices that employ such lenses. The multifunctional Fresnel lenses having combined refractive and diffractive functionalities are always desirable in sensing and optical communications.…”

“…The fabrication of such multifunctional lenses is vital in developing miniature spectrometers where the visible light is converted into a spectral image by an image-processing algorithm. [40] 2. Experimental Section…”