Trends

Trends

Technology | Jul 28, 2010
White OLED Outlook Brightens with Efficiency Breakthrough
White OLED Outlook Brightens with Efficiency Breakthrough GE Global Research, the technology development arm for the General Electric Company (NYSE: GE), GE Lighting and Konica Minolta (KM) have achieved a major breakthrough that brings the companies closer to making high-efficiency organic light-emitting diode (OLED) lighting devices a reality. GE and KM scientists have demonstrated illumination-quality white OLEDs using “solution-coatable” materials that are essential for producing OLEDs at a low cost. Read more »
Technology | Jul 28, 2010
Prototype of a Red Golden Dragon Plus LED Sets New Record
Prototype of a Red Golden Dragon Plus LED Sets New Record Developers at OSRAM Opto Semiconductors have succeeded in increasing the efficiency of red thin-film LEDs by 30% – a new record. The latest generation of thin-film chips benefit from an optimized chip platform which has potential for further improvements. This boost in efficiency is opening up new LED applications in general illumination, in projection and in the industrial sector. Read more »
Technology | Jul 16, 2010
LED – Cooling and Thermal Management
LED – Cooling and Thermal Management As we all know, the life span of an LED depends on the semi-conductor material used as well as the current/heat relationship. The light output of the LED becomes weaker and weaker and once it reaches 50% of its initial value, the life expectancy of the LED has, by definition, been reached. A life span of a few hundred and up to 100,000 hours is possible, but only when avoiding high temperatures which drastically reduce the length of the LED’s life. Read more »
Technology | Jul 13, 2010
The Future of OLED Lighting
The Future of OLED Lighting Organic light-emitting diodes (OLEDs) are currently a hot topic in the lighting industry. With major companies such as Osram, Philips, and General Electric displaying prototype products and announcing commercial availability of OLED panels for prototype lighting applications, it is difficult to ignore the industry buzz: “OLEDs are the future of lighting!” Read more »
Technology | Dec 30, 1969
Measurement of LEDs
Measurement of LEDs Various new types of light emitting diodes (LEDs) are being developed and introduced for general illumination and other applications, and there are increasing needs for accurate measurements of various optical parameters of LEDs. Traditional standard lamps do not meet the calibration needs for LED measurements as LEDs differ substantially from traditional lamps in terms of physical sizes, flux levels, spectra, and spatial intensity distributions. Read more »
Technology | Dec 30, 1969
Off-Line LED Control Circuit
Off-Line LED Control Circuit Resonant mode topologies offer many benefits over traditional buck, boost and flyback solutions. These include soft-switching, higher operating frequencies, higher power density and higher efficiency. Electronic ballast designs for fluorescent lighting applications have already been taking advantage of these benefits for many decades. Much can be learned from electronic ballast circuits and applied to LED driver circuits. This article compares the load requirements for fluorescent lamps and LEDs, explains the functionality of a new dimming electronic ballast control IC, and describes a new resonant mode control circuit for LEDs that uses the new IC. Experimental results of the new circuit are also presented and summarized to show final performance. Read more »
Technology | Dec 30, 1969
Electrical Considerations of LED Bulbs
Electrical Considerations of LED Bulbs Governments all over the world regulated the future use of the inefficient incandescent lamps. For example, the member states of the European Union agreed to a phasing out of incandescent lamps by 2012. The initial European-wide ban applies the first step to “nondirectional” light bulbs. The first types of bulbs to be banned are frosted (non-clear) bulbs and clear bulbs over 100 W, which will be phased out completely by September 2009. The power limit will be moved down to lower wattages, and the efficiency levels raised by the end of 2012. Read more »
Technology | Dec 30, 1969
High Quality GaN Substrates for Modern LED Technology
High Quality GaN Substrates for Modern LED Technology It is well known that modern III-nitride based technologies for light emitting diode (LED) production include (as an initial inevitable step) the preparation of GaN templates. Such GaN templates are usually delivered on foreign substrates possessing high lattice mismatch with respect to GaN layers, e.g., sapphire or silicon carbide substrates. The growth of GaN layers on highly mismatched substrates occurs via the formation of 3D islands with their following coalescence [1]. Such growth mode results in an extremely high density of threading dislocations (TDs) up to 1010–1011 cm–2 in the layer interior [1]. These TDs are known as main sources for the deleterious performance of LEDs and other GaN based electronic and optoelectronic devices [2]. Therefore there exists an ultimate necessity in the developing of effective and low-cost recipes for low TD density GaN template manufacturing. Read more »
Technology | Dec 30, 1969
Microstructured Optics for LED Applications
Microstructured Optics for LED Applications Optics for use with Light Emitting Diodes are described. Microstructured optics are available and customizable for a wide variety of applications. A few of these will be touched on. A methodology of designing these optics and the photometrics of the typical technology is overviewed. Read more »
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