LED

LEDs evolve to meet need for more illumination in a smaller package

A number of trends are driving innovation in the LED market. Many handheld products are becoming multifunctional and require both backlighting and illumination. Also, the need for smaller and brighter LEDs keeps growing with the increasing demand for handheld products, from cell phones that can play Web-based games and videos to portable medical monitoring equipment for home-based patients. LEDs are also becoming more popular due to their reduced energy consumption. With power management becoming more of an issue with multifunctional portable devices, LEDs manufacturers have put an emphasis on energy efficiency.

Multi-functional Backlights

Global Lighting Technology Inc. had produced Microlens edge-lighting modules that provide LED backlighting for LDCs that serves a multitude of functions with a minimum of LEDs. The modules were designed to produce bright, clean, uniform white LED backlighting from an ultra-thin, low-power package, as well as providing discrete area backlighting for different parts of the display. The functions include backlighting of the LCD, overlays (characters, logos) buttons, keypads and any other areas — however many — that needs illumination.

The Microlens light guide measures 4.3 inches at its widest point and 4.5 inches at its longest point and only 0.8 mm in thickness. The areas of illumination can include the main 4.3 × 5 inch LCD areas, as well as characters and directional symbols at the top and sides of the unit. Illumination can range from straight backlighting of the LCD characters and symbols to a halo effect around the keypad buttons. This is both aesthetic and functional. In addition, raised mechanical features are designed into the light guide, providing an easy solution for positioning the LCD, as well as a slotted zebra strip holder for connection between the elastometric connector and the PC board. http://rbi.ims.ca/5406-579

Small and Bright LED Developed

Philips Lumileds has introduced the Luxeon Rebel power LEDS with new packaging technology that reduces the size of the LED and enables new approaches to solid-state lighting design. The LED was engineered for operation between 350 and 1,000 mA. Philips is offering guaranteed minimum performance specifications that are intended to enable greater design and manufacturing consistency, as well as allowing customers to purchase the light output performance appropriate for each application.

For applications requiring high efficacy, the cool-white Luxeon Rebel can exceed 70 lm/W at 350 mA. When total light output needs to be maximized, the LED delivers more than 160 lm at high drive currents. Warm-white, neutral-white and cool-white color temperatures in addition to standard InGaN and AlInGaP colors provide the most complete color palette for lighting designers. Philips says the Luxeon Rebel is 3 × 4.5 mm. The small footprint and low profile, just 2.1 mm, enable reduced color missing and diffusion depths so laminate designs can be as much as 50 percent slimmer than with conventional power LEDs. http://rbi.ims.ca/5406-577

High-Intensity Power SMD LEDs in Ceramic Package

Vishay Intertechnology Inc. has released a series of high-intensity yellow, amber and white SMD LEDs in the CLCC6 ceramic package. The VLMx61 series offers a very low thermal resistance and high optical power for thermal-sensitive applications. The CLCC6 ceramic package devices allow the additional current drive for a maximum light output while maintaining a high service life of up to 50,000 hours. It's high-efficiency heat dissipation makes the CLCC6 a good source for clustered or matrix designs where the cumulative heat is a key consideration.

The new LEDs in the VLMx61 series are optimized for backlighting and illumination in automotive and transport, consumer and general applications. Typical end products include handheld mobile devices, traffic lights, household applications — such as washers, dryers and refrigerators — and exterior automotive lighting such as turning blinkers and brake lights. All of the devices in the series offer a 60 degree half-intensity angle and are compatible with IR-reflow solder processes in accordance with CECC 00802 and J-STD-020C. The package is preconditioned according to JEDEC Level 4a standards. The CLCC6 is also lead-free and automotive-qualified to AEC-Q101. http://rbi.ims.ca/5406-578

Small Fuse for Space Applications

Schurter Group has developed a SMD fuse type MGA-S that meets the standard of ESA/SCC Generic Specification No. 4008 for space applications. Based on the design of Schurter's existing MGA, the new version meets the requirements of the space industry and its demands for a fuse product with hermetic seal and robust construction so that no arcs or gases can escape with a disconnect. The requirements also include additional pre-arcing times, consistency of over-current disconnects at rated voltage regardless of vacuum conditions, stable derating curves at higher ambient temperatures and durability against mechanical vibration and shock.

The key difference between a fuse for aerospace and a standard fuse lies with the requirements of the component itself. Every single component is extensively tested by means of a "burn-in" procedure to validate correct functioning. The technology widely used for standard fuses today is not able to fulfill the requirements for long-term reliability of 20 to 30 years. The long-term stability is influenced by leakage loss, ageing and ambient temperature in combination with thermal cycles that are prevalent in satellite applications. The MGA-S with its thin-film technology (metal sputter process) increases the long-term stability of the fuse through the homogeneous crystal structure of the metal layers.

http://rbi.ims.ca/5406-580