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Products | White High Power LEDs
EPISTAR Achieves 135lm/W White LED at 1W Operation
EPISTAR announces it has developed a High-Voltage (HV) LED chip that enables 135 lm/W white LED at 1W operation and has begun shipping its high-voltage (HV) chips to General Electric (GE), Philips, Osram and IKEA. Read more »
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Technology | Optics
Primary and Secondary Optic Materials - LED Luminaire Performance and Lifetime
Numerous articles have been published regarding the lifetime of Light Emitting Diode (LED) luminaires, however, the primary focus has typically been on the lifetime of the LED die itself. Given that the LED luminaire is a system, it is important to recognize all aspects of the system that can affect or limit lifetime. Read more »
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Technology | Measurement
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 »
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Technology | Electronics
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 ... Read more »
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- Technology | Light Generation
High Quality GaN Substrates for Modern LED Technology
Figure 3: AFM data illustrating the NI density for a) sample A and b) sample B. The overgrowth of sparse NIs can result in formation of new islands (c). Using increased reactor pressure the formation of new islands during HT overgrowth can be suppressed (d). All the scans are 10 μm × 10 μm.
Figure 1: Schematic of cross-sectional view of the growing GaN layer: (a) stage I – inclination of TDs during growth; dashed line represents partially coalesced islands with TDs terminating at bottoms of grooves; at the interface TDs close up and form a misfit dislocation (MD); (b) stage I – optional filling of grooves with mask material to enhance the probability for TD inclination; (c) stage II – regrowth step with flattened surface and TD reactions.
Figure 2: Model results for TD density reduction in redirection reaction layer structure: (a) relative TD density for structures with initial density ρ0 = 1010cm-2 and representative values for the parameter ρ = 0.5 (1), 1 (2), 2 (3); (b) absolute TD density in case ρ = 1 and various initial densities ρ0=1010 (1), 109 (2), 108 (3) cm-2. For all plots the dislocation reaction parameter κ = 100 nm. The total layer thickness includes both redirection and reaction parts.
Figure 4: Cross-section TEM data from a NI overgrown at HT with a low V/III ratio. TDs incline to become perpendicular to high-index facets of the NI.
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 »
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Products | Sockets & Connectors | Sep 02, 2010
Tyco Electronic's Solderless Socket Solution Now Ready for Shipping
Tyco Electronics (TE), a global leader in engineered electronic components and solutions, releases the solderless LED socket, Type CM (see also LpO News - May 26, 2010) , for easy integration of the new Cree XLamp® MP-L™ multichip LED into light fixtures. Introduced as a development program at LIGHTFAIR® International 2010, the product family is now available for production orders. Read more »
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Products | LED Fixtures | Sep 01, 2010
Cooper Lighting Introduces Recessed LED Indirect Luminaire
Cooper Lighting's unique reflector design provides optimum light levels with glare-free illumination for general lighting applications. Read more »
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Products | Simulation Tools | Sep 01, 2010
Lambda Research Corp. Releases TracePro 7.0, Optomechanical Design Software with Multi-Threading Capability
TracePro 7.0 increases raytracing speed up to 10 times over the 6.0 version using new multi-threading algorithms. This release also features a new interactive optimizer, rearrangeable system tree, new Reptile™ geometries and irradiance options. Read more »
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Products | LED Modules | Aug 31, 2010
New Design by HPI High Power LED Lightings
HPI introduced LED modules with excellent thermal performance, and easy replacement and maintenance. Read more »
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Case Studies | Museum Lighting | Aug 31, 2010
New Lighting Solution for Hamburg’s Museum of Art and Industry
At the refurbished Museum of Art and Industry, the multifunctional Supersystem LED lighting system works at its best: paintings and sculptures are highlighted in all their facets by its attractive, brilliant light. Read more »
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Products | Lamps | Aug 31, 2010
Jincos Introduces Eco×Smart+Green LED Replacement Bulb with Wide Dimming Range
Jincos LED lighting bulb series products provides wide dimming range from 2% to 100%, in contrast to most other dimmable bulbs from the market which only support 5% to 100%. Great effort of the Jincos RD team was necessary to bring the lowest brightness level down to 2%. Read more »
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Products | Raw Materials | Aug 31, 2010
Cree Demonstrates High Quality 150-mm Silicon Carbide Substrates
Cree, Inc. announced today that it has achieved a major breakthrough in the development and wide scale commercialization of silicon carbide (SiC) technology with the demonstration of high quality, 150-mm SiC substrates with micropipe densities of less than 10/cm2. The current Cree standard for SiC substrates is 100-mm diameter material. Read more »
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Business | Company News | Aug 31, 2010
The Taiwan-based LED Manufacturer Lextar Electronics Is Busy Building New Facilitates and Expanding its MOCVD Growth Capabilities.
Lextar Electronics Corporation, a Taiwan-based manufacturer of LED chips, epiwafers and packages, as well as solid-state Lighting products, has reported strong quarterly results and is planning to install MOCVD systems that are capable of LED growth on 6-inch wafers. Read more »
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Products | LED Fixtures | Aug 30, 2010
Astera’s Wireless LED Event Lights Now Shipping
Astera, manufacturer of high-tech LED solutions, now offers his product range of wireless LED lights and controllers to the public. After an initial testing-phase the LED fixtures have proven reliable and without battery-problems or long-term shortcomings and the company has started mass-production. Read more »
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Products | LED Optics | Aug 30, 2010
Fascinating Effects with PLEXIGLAS® Textured Sheet RADIANT
PLEXIGLAS® Textured Sheet RADIANT, the new product that Evonik is set to offer from September, is guaranteed to grab attention. For one thing, its textured surface diffuses light in an interesting way. For another, it creates colors that change according to the viewing angle, which is known as the RADIANT effect. Passersby see a colorful play of hues that is set off to particular advantage by the surface texture. Read more »
