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Hitachi Cable Develops High
Power 55-Lumen Red LED Chips
Templates
for Blue &
HITACHI CABLE has announced the high as 55 lumens. One of the methods of
development of a high-power red LED chip improving per-chip light output is to increase
offering a maximum luminous flux of 55 the chip dimensions. However, larger chips
UV LEDs
lumens. This was enabled by increasing the increase the difficulty in distributing a
size of the LED chip and use of a fine line uniform current across the entire light
electrode structure. emitting layer. If large electrodes are
GaN, AlN, AlGaN,
positioned in the upper layer of the chip for
InN, InGaN
Hitachi Cable manufactures supplies a more uniform current dispersion, light from
aluminum gallium arsenide (AlGaAs) the light emitting layer will be blocked,
epitaxial wafers and aluminum gallium reducing the light extraction efficiency.
indium phosphorus (AlGaInP) epitaxial
wafers, both of which are compound To resolve these problems in developing a
semiconductor wafers for red LEDs. In new LED chip, instead of using larger
response to demand for LEDs of higher electrodes, Hitachi Cable has utilized two
luminous efficiency, the company has also pad electrodes for receiving power, a
developed a high-brightness red LED chips backbone electrode connecting the two
(hereafter referred to as an “MR-LED electrodes, and multiple fine line electrodes
chips”) that form a metal reflector (MR) that extend from the backbone electrode on
under the light emitting layer. This product is the upper chip layer.
currently being supplied to LED package
manufacturers and other customers. By employing fine line electrodes, Hitachi
Cable has achieved uniform dispersion of
Through its LED business, Hitachi Cable current across the chip surface without
has recognized the growing demand for blocking light from the light emitting layer,
World leaders in development
higher output LED chips. The company has attaining a maximum luminous flux of 55 of Hydride Vapour Phase Epitaxy
incorporated fine electrode structures and lumens in a large LED chip measuring 1 mm
(HVPE) processes and techniques
enlarged chip dimensions to develop high- by 1 mm—equivalent to the combined output
for the production of novel
power red LED chips offering outputs as of 21 MR-LED chips (0.33 mm x 0.33 mm).
compound semiconductors
•
Templates
OLED wallpaper
grant to the firm so that the semiconductor
•
Wafer size: 50mm-150mm
technology can be used in both commercial •
Research grade InGaN wafers
could replace
and residential premises, as well as on the
•
Custom design epitaxy
roads to light barriers and signs without the
need for mains electricity.
•
Contract development
traditional lights
•
Small and large batch
Ken Lacey, chief executive of Lomox, said quantities available
the company has developed a chemical
which reduces the cost and overcomes the
Wide range of materials (GaN,
SEMICONDUCTOR TECHNOLOGY in the lifespan issues associated with OLEDs.
AlN, AlGaN, InN and InGaN)
form of OLEDs could replace conventional “This is a chemical that in a flat panel
on different sizes and types of
light fittings by being coated on to film display screen you can put it in the device substrates (sapphire or SiC)
which acts as wallpaper. Semiconductor and it emits light. In a light you can put it
technology has been used to develop the anywhere. You can paint it on a wall or
Contact us now!
potential for light bulbs to be replaced with wallpaper,” he stated. Email:
plasma@oxinst.com
thin film that can cover walls like wallpaper. Technologies and Devices International
Tel: +1 301 572 7834
Organic light emitting diodes (OLEDs) have
www.oxford-instruments.com/tdi1
been used by Welsh company Lomox to
create next-generation and low-carbon amsung
lighting for homes and businesses. OLEDs
are coated on to thin flexible films to create
the wall panels, although they can also be
applied to mobile telephone displays, flat
Photo credit: S
screen televisions and computers. The
Carbon Trust has awarded a £454,000
January/February 2010
www.compoundsemiconductor.net 13
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