The Semiconductor p–n Junction “Ultimate Lamp”

MRS Bulletin ◽  
2005 ◽  
Vol 30 (7) ◽  
pp. 515-517 ◽  
Author(s):  
Nick Holonyak
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Flat Band ◽  
Thin Sample ◽  
Light Emitting ◽  
Recombination Radiation ◽  
A Current

AbstractSimple diagrams are used to show the transformation of a thin sample of intrinsic, direct-gap semiconductor from an ideal “flat-band” photopumped recombination-radiation light source into a current-driven, p–n junction “ultimate lamp,” a light-emitting diode.

Comparison of the effects of operating microscopes with light emitting diode and halogen light source on the eye: a rabbit study

2021 ◽  
pp. 1-7
Author(s):  
Bahri Aydın ◽  
Armagan Ozgur ◽  
Huseyin Baran Ozdemir ◽  
Pınar Uyar Gocun ◽  
Mehmet Arda Inan ◽  
...  
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Halogen Light ◽  
Halogen Light Source

scholarly journals Influences of Spectral Power Distribution on Circadian Energy, Visual Comfort and Work Performance

2021 ◽  
Vol 13 (9) ◽  
pp. 4852
Author(s):  
Jack Ngarambe ◽  
Inhan Kim ◽  
Geun Young Yun
Keyword(s):  
Light Source ◽  
Power Distribution ◽  
Work Performance ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Essential Element ◽  
Visual Comfort ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Spectral Power Distribution

Spectral power distribution (SPD) is an essential element that has considerable implications on circadian energy and the perception of lit environments. The present study assessed the potential influences of SPD on energy consumption (i.e., considering circadian energy), visual comfort, work performance and mood. Two lighting conditions based on light-emitting diode (LED) and organic light-emitting diode (OLED) were used as proxies for SPDs of different spectral content: dominant peak wavelength of 455 nm (LED) and 618 nm (OLED). Using measured photometric values, the circadian light (CL), melatonin suppression (MS), and circadian efficacy (CE) of the two lighting sources were estimated via a circadian-phototransduction model and compared. Additionally, twenty-six participants were asked to evaluate the said lit environments subjectively in terms of visual comfort and self-reported work performance. Regarding circadian lighting and the associated energy implications, the LED light source induced higher biological actions with relatively less energy than the OLED light source. For visual comfort, OLED lighting-based conditions were preferred to LED lighting-based conditions, while the opposite was true when considering work performance and mood. The current study adds to the on-going debate regarding human-centric lighting, particularly considering the role of SPD in energy-efficient and circadian lighting practices.

scholarly journals Optimal Color Lighting for Scanning Images of Flat Panel Display using Simplex Search

2018 ◽  
Vol 4 (11) ◽  
pp. 133
Author(s):  
HyungTae Kim ◽  
EungJoo Ha ◽  
KyungChan Jin ◽  
ByungWook Kim
Keyword(s):  
Image Quality ◽  
Light Source ◽  
Light Emitting Diode ◽  
Optical Filters ◽  
Flat Panel Display ◽  
Flat Panel ◽  
Light Emitting ◽  
Simplex Search ◽  
Inspection Systems ◽  
Color Control

A system for inspecting flat panel displays (FPDs) acquires scanning images using multiline charge-coupled device (CCD) cameras and industrial machine vision. Optical filters are currently installed in front of these inspection systems to obtain high-quality images. However, the combination of optical filters required is determined manually and by using empirical methods; this is referred to as passive color control. In this study, active color control is proposed for inspecting FPDs. This inspection scheme requires the scanning of images, which is achieved using a mixed color light source and a mixing algorithm. The light source utilizes high-power light emitting diodes (LEDs) of multiple colors and a communication port to dim their level. Mixed light illuminates an active-matrix organic light-emitting diode (AMOLED) panel after passing through a beam expander and after being shaped into a line beam. The image quality is then evaluated using the Tenenbaum gradient after intensity calibration of the scanning images. The dimming levels are determined using the simplex search method which maximizes the image quality. The color of the light was varied after every scan of an AMOLED panel, and the variation was iterated until the image quality approached a local maximization. The number of scans performed was less than 225, while the number of dimming level combinations was 20484. The proposed method can reduce manual tasks in setting-up inspection machines, and hence is useful for the inspection machines in FPD processes.

scholarly journals A Planar, Chip-Based, Dual-Beam Refractometer Using an Integrated Organic Light-Emitting Diode (OLED) Light Source and Organic Photovoltaic (OPV) Detectors

2010 ◽  
Vol 82 (7) ◽  
pp. 2734-2742 ◽  
Author(s):  
Erin L. Ratcliff ◽  
P. Alex Veneman ◽  
Adam Simmonds ◽  
Brian Zacher ◽  
Daniel Huebner ◽  
...  
Keyword(s):  
Light Source ◽  
Light Emitting Diode ◽  
Organic Photovoltaic ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Dual Beam

An intraocular micro light-emitting diode device for endo-illumination during pars plana vitrectomy

2018 ◽  
Vol 29 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Philipp S Koelbl ◽  
Christian Lingenfelder ◽  
Christoph W Spraul ◽  
Juergen Kampmeier ◽  
Frank HJ Koch ◽  
...  
Keyword(s):  
Light Source ◽  
Pars Plana Vitrectomy ◽  
Light Emitting Diode ◽  
Outer Diameter ◽  
Continuous Exposure ◽  
Thermal Hazards ◽  
Light Emitting ◽  
Illumination System ◽  
Single Use ◽  
Pars Plana

Purpose: Development of a new, fiber-free, single-use endo-illuminator for pars plana vitrectomy as a replacement for fiber-based systems with external light sources. The hand-guided intraocularly placed white micro light-emitting diode is evaluated for its illumination properties and potential photochemical and thermal hazards. Methods: A micro light-emitting diode was used to develop a single-use intraocular illumination system. The light-source-on-tip device was implemented in a prototype with 23G trocar compatible outer diameter of 0.6 mm. The experimental testing was performed on porcine eyes. All calculations of possible photochemical and thermal hazards during the application of the intraocular micro light-emitting diode were calculated according to DIN EN ISO 15007–2: 2014. Results: The endo-illuminator generated a homogeneous and bright illumination of the intraocular space. The color impression was physiologic and natural. Contrary to initial apprehension, the possible risk caused by inserting a light-emitting diode into the intraocular vitreous was much smaller when compared to conventional fiber-based illumination systems. The photochemical and thermal hazards allowed a continuous exposure time to the retina of at least 4.7 h. Conclusion: This first intraocular light source showed that a light-emitting diode can be introduced into the eye. The system can be built as single-use illumination system. This light-source-on-tip light-emitting diode–endo-illumination combines a chandelier wide-angle illumination with an adjustable endo-illuminator.

Simple, Accurate Solid-State Diode Photometer for Use in Measuring Oxygen Saturation of Whole Blood

1974 ◽  
Vol 20 (9) ◽  
pp. 1135-1137 ◽  
Author(s):  
R Fesler ◽  
Th Clerbaux
Keyword(s):  
Solid State ◽  
Oxygen Saturation ◽  
Light Source ◽  
Whole Blood ◽  
Continuous Measurement ◽  
Light Emitting Diode ◽  
Detector Response ◽  
Typical Application ◽  
Light Emitting ◽  
Absorption Characteristics

Abstract A small, easily-built photometer is described, in which a solid-state light-emitting diode is used as the light source and a phototransistor as the detector. The detector response is kept constant by modulating the diode intensity in proportion to the absorption characteristics of the sample being analyzed. Linearity and stability are good, even with turbid solutions (drift is <0.001 absorbance unit per hour). A typical application of this photometer is the continuous measurement of the percentage of oxyhemoglobin (0 to 100 %) in blood. For hemoglobin concentrations from 3 to 18 g/dl, the relation between oxyhemoglobin as estimated with this diode photometer and by a galvanic method (LEX-O2-CON) was: SO2LED = 0.993 SO2 % LEX + 0.69;r = 0.9975; n = 129; Syx = 1.59.

Recycled Thermal Energy from High Power Light Emitting Diode Light Source

2018 ◽  
Vol 18 (9) ◽  
pp. 6029-6032
Author(s):  
Jae-Hoon Ji ◽  
GaeHun Jo ◽  
Jae-Geun Ha ◽  
Sang-Mo Koo ◽  
Masao Kamiko ◽  
...  
Keyword(s):  
Light Source ◽  
Thermal Energy ◽  
High Power ◽  
Light Emitting Diode ◽  
Light Emitting
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