Illumination and Color Control in Red-Green-Blue Light-Emitting Diode

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.

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In vitro and in vivo Efficacy of New Blue Light Emitting Diode Phototherapy Compared to Conventional Halogen Quartz Phototherapy for Neonatal Jaundice

Journal of Korean Medical Science ◽

10.3346/jkms.2005.20.1.61 ◽

2005 ◽

Vol 20 (1) ◽

pp. 61 ◽

Cited By ~ 23

Author(s):

Yun Sil Chang ◽

Jong Hee Hwang ◽

Hyuk Nam Kwon ◽

Chang Won Choi ◽

Sun Young Ko ◽

...

Keyword(s):

Blue Light ◽

Neonatal Jaundice ◽

Light Emitting Diode ◽

In Vivo Efficacy ◽

Light Emitting

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Operando direct observation of spin-states and charge-trappings of blue light-emitting-diode materials in thin-film devices

Scientific Reports ◽

10.1038/s41598-020-75668-4 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Fumiya Osawa ◽

Kazuhiro Marumoto

Keyword(s):

Blue Light ◽

High Performance ◽

Density Functional ◽

Light Emitting Diode ◽

Green Light ◽

Spin States ◽

Light Emitting ◽

Full Color ◽

Color Displays ◽

Materials Used

Abstract Spin-states and charge-trappings in blue organic light-emitting diodes (OLEDs) are important issues for developing high-device-performance application such as full-color displays and white illumination. However, they have not yet been completely clarified because of the lack of a study from a microscopic viewpoint. Here, we report operando electron spin resonance (ESR) spectroscopy to investigate the spin-states and charge-trappings in organic semiconductor materials used for blue OLEDs such as a blue light-emitting material 1-bis(2-naphthyl)anthracene (ADN) using metal–insulator–semiconductor (MIS) diodes, hole or electron only devices, and blue OLEDs from the microscopic viewpoint. We have clarified spin-states of electrically accumulated holes and electrons and their charge-trappings in the MIS diodes at the molecular level by directly observing their electrically-induced ESR signals; the spin-states are well reproduced by density functional theory. In contrast to a green light-emitting material, the ADN radical anions largely accumulate in the film, which will cause the large degradation of the molecule and devices. The result will give deeper understanding of blue OLEDs and be useful for developing high-performance and durable devices.

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Optimization and evaluation of a blue light photoinitiating system for textile inkjet printing

Textile Research Journal ◽

10.1177/0040517518783346 ◽

2018 ◽

Vol 89 (10) ◽

pp. 1964-1974

Author(s):

Yi Huang ◽

Guangdong Sun ◽

Yating Ji ◽

Dapeng Li ◽

Qinguo Fan ◽

...

Keyword(s):

Blue Light ◽

Light Emitting Diode ◽

Absorption Efficiency ◽

Polymerization Rate ◽

Nozzle Clogging ◽

Light Emitting ◽

Custom Made ◽

Light Curing ◽

Set Up ◽

Pigment Ink

A blue light curing process was developed to solve the nozzle clogging challenge commonly encountered in conventional textile pigment printing, by using camphorquinone (CQ) and ethyl-4-dimethylaminobenzoate (EDMAB) as a photoinitiator combination and substituting oligomers and monomers for a polymeric binder. High light absorption efficiency was insured by closely matching the spectrum of the photoinitiator with a custom-made blue light light-emitting diode set-up. Kinetic analyses of such a CQ/EDMAB system indicated that the maximum polymerization rate of the monomer was proportional to [PI]0.5 and [I0]0.5, while excessive high photoinitiator concentration (>1 wt%) will decrease the polymerization rate because of the “filter effect.” With optimized blue light curable pigment ink formula and irradiation conditions, the photocurable pigment printed fabrics exhibited uniform and vibrant colors, clear outlines, and excellent wet and dry rubbing fastness of grades 4 and 4–5, respectively.

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