A Compact Raster Lensless Microscope Based on a Microdisplay.
TL;DR: In this paper, the smallest practical microscopy is demonstrated, where the object is located near the lighting source and the maximum resolution relies on reduced LED size and the position of the sample respect the microdisplay.
Abstract: Lensless microscopy requires the simplest possible configuration, as it uses only a light source, the sample and an image sensor. The smallest practical microscope is demonstrated here. In contrast to standard lensless microscopy, the object is located near the lighting source. Raster optical microscopy is applied by using a single-pixel detector and a microdisplay. Maximum resolution relies on reduced LED size and the position of the sample respect the microdisplay. Contrarily to other sort of digital lensless holographic microscopes, light backpropagation is not required to reconstruct the images of the sample. In a mm-high microscope, resolutions down to 800 nm have been demonstrated even when measuring with detectors as large as 138 μm × 138 μm, with field of view given by the display size. Dedicated technology would shorten measuring time.
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TL;DR: In this paper , the authors review and discuss typical computational, portable and low-cost microscopes by refined specifications and schematics, from the aspect of optics, electronic, algorithms principle and typical bio-medical applications.
Abstract: In bio-medical mobile workstations, e.g., the prevention of epidemic viruses/bacteria, outdoor field medical treatment and bio-chemical pollution monitoring, the conventional bench-top microscopic imaging equipment is limited. The comprehensive multi-mode (bright/dark field imaging, fluorescence excitation imaging, polarized light imaging, and differential interference microscopy imaging, etc.) biomedical microscopy imaging systems are generally large in size and expensive. They also require professional operation, which means high labor-cost, money-cost and time-cost. These characteristics prevent them from being applied in bio-medical mobile workstations. The bio-medical mobile workstations need microscopy systems which are inexpensive and able to handle fast, timely and large-scale deployment. The development of lightweight, low-cost and portable microscopic imaging devices can meet these demands. Presently, for the increasing needs of point-of-care-test and tele-diagnosis, high-performance computational portable microscopes are widely developed. Bluetooth modules, WLAN modules and 3G/4G/5G modules generally feature very small sizes and low prices. And industrial imaging lens, microscopy objective lens, and CMOS/CCD photoelectric image sensors are also available in small sizes and at low prices. Here we review and discuss these typical computational, portable and low-cost microscopes by refined specifications and schematics, from the aspect of optics, electronic, algorithms principle and typical bio-medical applications.
1 citations
TL;DR: In this article , the authors demonstrate chip-sized microscopes produced only with microelectronic technologies, with a LED micro-display as a main component and a photodetector, both raster and multi-holographic lensless microscopes.
Abstract: Light microscopy has changed considerably over the last century. Nevertheless, it still suffers the limitation of being performed in laboratories, what causes delays to results, partial sampling and non-continuous measurements. Here we will demonstrate chip-sized microscopes produced only with microelectronic technologies. With a LED micro-display as a main component and a photodetector, both raster and multi-holographic lensless microscopes were demonstrated. The field of view of the microscopes is given by the micro-display area while LED size limits the resolution. Their low cost in volume manufacturing and chip-sized compactness will allow ubiquitous microscopy soon.
16 Nov 2022
TL;DR: In this article , an in-pixel driving circuit with switching capabilities up to 1MHz and LED bias current up to 120µA was presented, which is designed to be integrated in a 512x512 microdisplay of 1411 ppi with 10kfps working capabilities.
Abstract: GaN technology have been a revolutionary development in the light emitting sources field. Their high efficiency, high bandwidth, high lifetime and high integration capabilities has opened a brand-new research field. Furthermore, the integration of hybrid microdisplays based on GaN-on-Si allowed the development of high efficiency visible light communication devices and new branch of image applications among others. In this work, we present an in-pixel driving circuit with switching capabilities up to 1MHz and LED bias current up to 120µA. The pixel driver is designed to be integrated in a 512x512 microdisplay of 1411 ppi with 10kfps working capabilities. The in-pixel driver allows to eliminate the leakage problems of the conventional drivers for hybrid interconnexion, besides having high brightness and high-speed capabilities.
16 Nov 2022
TL;DR: In this paper , a CMOS backplane was proposed to exploit the capabilities of the GaN-based micro-arrays, which can drive an array of GaN LED pixels of up to 512x512 of 1411 PPI (pixel per inch).
Abstract: GaN-on-Si based hybrid microdisplays have been the revolution as point-like light sources for scientific, communications, and imaging applications because of their high-resolution, high-brightness, and high-speed capabilities. Nevertheless, the microdisplay driving circuits usually focus only on two of these characteristics. In this work, we present a CMOS backplane that aims to exploit the capabilities of the GaN-based micro-arrays. The back panel can drive an array of GaN LED pixels of up to 512x512 of 1411 PPI (pixel per inch) with an in-pixel driver that offers a bias current up to 120 μA. The smart pixel control circuit has a 4-bit grayscale resolution. Frames can be updated at up to 10 kfps. Finally, the backplane can be operated in pulsed mode, toggling the entire array between the stored frame and off state at 1 MHz. The backplane design in 180 nm CMOS process and the in-pixel driver simulations results are presented.
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TL;DR: An iterative phase retrieval method that uses a series of diffraction patterns, measured only in intensity, to solve for both amplitude and phase of the image wave function over a wide field of view and at wavelength-limited resolution is proposed.
Abstract: We propose an iterative phase retrieval method that uses a series of diffraction patterns, measured only in intensity, to solve for both amplitude and phase of the image wave function over a wide field of view and at wavelength-limited resolution. The new technique requires an aperture that is scanned to two or more positions over the object wave function. A simple implementation of the method is modeled and demonstrated, showing how the algorithm uses overlapping data in real space to resolve ambiguities in the solution. The technique opens up the possibility of practical transmission lensless microscopy at subatomic resolution using electrons, x rays, or nuclear particles.
707 citations
TL;DR: The resolution of conventional optical lens systems is always hampered by the diffraction limit, but recent developments in artificial metamaterials provide new avenues to build hyperlenses and metalenses that are able to image beyond the diffracted limit.
Abstract: The resolution of conventional optical lens systems is always hampered by the diffraction limit. Recent developments in artificial metamaterials provide new avenues to build hyperlenses and metalenses that are able to image beyond the diffraction limit. Hyperlenses project super-resolution information to the far field through a magnification mechanism, whereas metalenses not only super-resolve subwavelength details but also enable optical Fourier transforms. Recently, there have been numerous designs for hyperlenses and metalenses, bringing fresh theoretical and experimental advances, though future directions and challenges remain to be overcome.
511 citations
TL;DR: This review conducts a comprehensive analysis on the material properties, device structures, and performance of mLED/μLED/OLED emissive displays and mLED backlit LCDs to compare the motion picture response time, dynamic range, and adaptability to flexible/transparent displays.
Abstract: Presently, liquid crystal displays (LCDs) and organic light-emitting diode (OLED) displays are two dominant flat panel display technologies Recently, inorganic mini-LEDs (mLEDs) and micro-LEDs (μLEDs) have emerged by significantly enhancing the dynamic range of LCDs or as sunlight readable emissive displays "mLED, OLED, or μLED: who wins?" is a heated debatable question In this review, we conduct a comprehensive analysis on the material properties, device structures, and performance of mLED/μLED/OLED emissive displays and mLED backlit LCDs We evaluate the power consumption and ambient contrast ratio of each display in depth and systematically compare the motion picture response time, dynamic range, and adaptability to flexible/transparent displays The pros and cons of mLED, OLED, and μLED displays are analysed, and their future perspectives are discussed
505 citations
TL;DR: Unique features of lens-free computational imaging tools are discussed and some of their emerging results for wide-field on-chip microscopy, such as the achievement of a numerical aperture of ∼0.8–0.9 across a field of view (FOV) of more than 20 mm2, which corresponds to an image with more than 1.5 gigapixels.
Abstract: In this perspective, the authors present the basic features of lens-free computational imaging tools and report performance comparisons with conventional microscopy methods. They also discuss the challenges that these computational on-chip microscopes face for their wide-scale biomedical application.
486 citations
TL;DR: The implementation and application of two high-resolution, lensless, and fully on-chip microscopes based on the optofluidic microscopy (OFM) method are reported, anticipating that the OFM can significantly address a range of biomedical and bioscience needs, and engender new microscope applications.
Abstract: Low-cost and high-resolution on-chip microscopes are vital for reducing cost and improving efficiency for modern biomedicine and bioscience. Despite the needs, the conventional microscope design has proven difficult to miniaturize. Here, we report the implementation and application of two high-resolution (≈0.9 μm for the first and ≈0.8 μm for the second), lensless, and fully on-chip microscopes based on the optofluidic microscopy (OFM) method. These systems abandon the conventional microscope design, which requires expensive lenses and large space to magnify images, and instead utilizes microfluidic flow to deliver specimens across array(s) of micrometer-size apertures defined on a metal-coated CMOS sensor to generate direct projection images. The first system utilizes a gravity-driven microfluidic flow for sample scanning and is suited for imaging elongate objects, such as Caenorhabditis elegans; and the second system employs an electrokinetic drive for flow control and is suited for imaging cells and other spherical/ellipsoidal objects. As a demonstration of the OFM for bioscience research, we show that the prototypes can be used to perform automated phenotype characterization of different Caenorhabditis elegans mutant strains, and to image spores and single cellular entities. The optofluidic microscope design, readily fabricable with existing semiconductor and microfluidic technologies, offers low-cost and highly compact imaging solutions. More functionalities, such as on-chip phase and fluorescence imaging, can also be readily adapted into OFM systems. We anticipate that the OFM can significantly address a range of biomedical and bioscience needs, and engender new microscope applications.
316 citations