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Light and Building 2008 Record numbers, LEDs and Energy Efficiency

issue 43 Jun / Jul 2008

One of the biggest lighting shows in the World didn’t fail to disappoint with Light and Building 2008 showing a large increase in visitor numbers, a strong emphasis on energy efficient lighting products and a plethora of LEDs! Dr Geoff Archenhold, took a look at what was new

Believe it or not, I just have not managed to make previous Light and Building shows but this year I managed to not only book a flight to Frankfurt but also got a relatively decent hotel near the centre enabling me to discover the best that the lighting industry had to offer between April 6th to 11th. This year the show managed to attract a huge 165,000 visitors with overall visitor numbers up by 22% compared with 2006 and with approximately 40% of visitors finding their way from outside of Germany. The event attracted 2173 exhibitors and I can categorically state that I did not manage to see even 10% of them and 6 days is certainly not enough time so the key is to pick your meetings and visits carefully!
Unfortunately, the shear size of the venue meant that it was all too easy for one to miss scheduled meetings as it could take 15-20 minutes to walk between Halls, so I must apologise to all of those that I didn’t get to meet. In fact, I would say that it was the unscheduled walk-about’s trying to locate the stand for the next meeting which proved more interesting as it would often unveil companies or products that are not often visible in the marketplace.
Light and Building 2008 proved to be LED and Energy Efficient focused and this month’s article is dedicated to a snapshot of interesting and exciting products that were launched during the show.

New high power LEDs
There was little news from the major LED manufacturers at the show, however there were some very interesting new entrants to the LED market with the promise of high power, high CRI and high lumen output LEDs.
The first of the new LED manufacturers was Amotech Europe based in London and the European subsidiary of Advanced Material on Technology of South Korea. Amotech demonstrated two high power LEDs running at 12W and 20W with the technical details highlighted in table 1. The impressive features of the LEDs were the high CRI of 90, the low thermal resistance of the packaging at just 2°C/W and the 20W package delivering more than 1300 Lumens as shown in Figure 1.
The second new entrant to launch a range of high power, high efficiency LEDs was Citizen from Japan. Citizen is well known for their research into high brightness LEDs more specifically as replacements for lasers in modern printers. However they have decided to bring their expertise to the general lighting market with an impressive range of white high power LED products.
The new product range includes white light LED emitters and small linear strips in a choice of two colour temperatures of 5000K and 2900K up to 16.9 watts in a package size of just 17.5 x 28 x 1.8 mm. Key features of the LED range include:

  • High CRI version “Ra of 95”
  • Low thermal resistance packages
  • CL-L190 series: 408lm for MR16 replacement
  • CL-L220 (2900K): 900lm LED higher than 60W incandescent bulb
  • CL-L220 (5000K): Highest lumen output, 1180lm, from 1 LED package
  • Flexible driving solution: Over achievable

Interestingly, Citizen have adopted smaller LED die used in conventional 5mm LED technology rather than the power LED die used by the majority of high power LED manufacturers. For example, the CL-654 package uses 8 LED die to obtain 1.2 watts normally achieved with a single 1mm2 LED power die. The advantages of using this method is that smaller die have been manufactured for much longer and the production yields are arguably better than power dies and the thermal management is slightly easier as the power density issues are not as demanding as with single high power die packages.
The CL-L220 single LED package offers a completely scalable package for LED fixture manufacturers to design around as it can offer a scalable lumen output from 300 Lumens to 1150 lumens in a single package. For the first time other than within this column, Citizen have produced a really useful graph which shows how the CL-L220 output increases and what happens to the LED efficiency as the light output is increased. Figure 2 shows the graph and indicates the CL-L220 achieves over 100 lumens per watt efficiency when driven at approximately 3.5W reducing down to an impressive 68 lumens per watt when driven at 16.5W.
The CL-L220 is certainly going to be an excellent choice for high output white lighting fixtures that demand scalability, flexibility, efficiency and raw lumen output.
Enfis also unveiled their UNO Warm White High CRI Array and Light Engine as shown in Figure 3. With a genuine broad spectral performance, the UNO Warm White High CRI product provides an exceptionally high quality, powerful spot source of light in a compact and cost-effective package. It has a CCT of 3200K under typical operating conditions, and can provide a CRI of >90.  The array is capable of producing 1000 lm from an emitting area of just 0.5cm2, providing a high power spot source. It is available as array only, or as a complete light engine with electronic and, if required, thermal management, ready to integrate into a luminaire.
It is very clear after visiting Light and Building 2008, the choice for general-lighting class white LEDs is rapidly increasing and the availability of high CRI and warm white eg; CRI>90 and CCT~2900K will mean consumers are able to have beautiful, digital, energy efficient light sources in their office and homes soon.

Efficient LED Downlighters
The really exciting news at the show was the launch of two new white LED downlighter products by UK companies IST and ACDC Lighting both of which were impressive and demonstrated that LEDs are more than a match for CFL or Halogen lamp technologies by meeting an efficacy of 45 lumens per Watt and Part L energy efficiency guidelines.
ACDC launched the Evolution downlighter, shown in figure 4, containing 9 Luxeon Rebels within each fixture which can be driven at both 350mA or 700mA depending upon which driver is specified. The Evolution comes in Cold, Neutral and Warm white LED options and three fixture variant of fixed, adjustable and trimless. Table 3 shows the lighting performance data for the Evolution products.
The Evolution can be driven at either 10W or 20W dependant upon the type of driver specified with the fixture enabling the designer to chose the power and efficiency of the fixture without having to purchase a different fixture.
Integrated System Technologies (IST) demonstrated their new downlighter range (see figure 5) by lighting the majority of the Future Lighting Solutions stand with a variety of cool and neutral white versions. The downlighters also use the latest Luxeon Rebel white LEDs and come in three versions of Cool, Neutral and Warm White. Interestingly, the IST fixtures contain 16 Rebel LEDs and can be driven from 10W right up to 40W using the novel thermal management design enabling the lighting designer to have the ultimate flexibility in terms of efficiency or high flux levels enabling less fixtures to be used within an office or corridor area.
The downlighter includes a novel optical design that reduces glare by simulating a non-LED light source. Indeed, many visitors to the FLS stand thought the downlighters were halogen rather than LED based as no individual LED could be seen when looking directly into the fixture making it a truly direct replacement for Compact Fluorescent Lamp downlighters. Figure 6 compares the Lux levels of a twin compact fluorescent downlighter with the IST cool white 20W downlighter showing that the IST product is over twice as efficient as the CFL equivalent and offers better on-axis Lux performance.
Table 4 highlights the technical characteristics of the IST LED downlighter which again provides impressive reading but also includes performance data of the fixture during operation. Interestingly, this is the first time to my knowledge that an LED fixture manufacturer has provided independent measured technical information on LED fixtures that have been in operation for more than an hour so steady state performance conditions could be observed.
Figure 7 shows two thermal images of the IST downlighter running at 40W or 700mA, the first highlights the maximum temperature of the LED metal clad board and also the junction temperatures of the LED array and the second shows the heat dissipation across the heatsink. Importantly, the Junction Temperatures of the LED array still only reaches 86°C when driven at 700mA providing excellent lifetime characteristics of the maximum 60,000 hours according to the lifetime datasheet provided by Philips Lumileds. Indeed, the junction temperature drops to less than 66°C when the downlighter is driven at 20W or 350mA.
Looking at the differences between the performance data for datasheet figures and those seen in true operation of the lighting fixture a -46% and -33% performance difference can be seen when the downlighter is operated at 40W (700mA) and 20W (350mA) respectively. Although, the performance figures are reduced compared to datasheet figures they represent the total system efficiency of the lighting fixture including any losses due to:

  • Operating Thermal performance of LEDs and fixture
  • LED driver efficiency
  • Optical efficiency

It looks as though IST has developed one of the first “CFL killer” LED fixtures that not only provides significant light output but should also be highly robust during its lifetime due to excellent thermal and optical management design.

Outdoor LED fixtures
A range of new outdoor LED fixtures were also launched during Light and Building 2008, the most interesting of which was the Martin Exterior 200 LED (reviewed in mondo*arc 42) which is a long-life programmable luminaire offering full RGB + Amber and White colour mixing. Weatherproofed for the dynamic illumination of outdoor architecture, it features a comprehensive colour range from 44 high power LEDs and choice of optional spread angles. Housed in a rugged casing, the Exterior 200 LED is perfect for applications where projection distance is limited as shown in figure 8.
With five coloured diodes (Red, Green, Blue, Amber and White) instead of the usual three, the Exterior 200 LED is able to offer a broader and finer range of colors. A greater variety of color shades and brighter saturated colors are possible compared to CMY systems. While the amber helps extend the colour range and give effective colour temperature control, the white diode provides a better white light quality and the ability to create softer, subtler pastels.
The Exterior 200 LED is available in a choice of narrow, medium or wide beam options for use at distances between approximately two to six meters (6 to 20 ft).

Street Lighting

A new 120W streetlight was launched by Alliance Optotek Corp of Taiwan based upon Nichia 1W high power LEDs. According to Alliance, the street light meets the full cut off request of the IESNA luminaire classification by combining symmetric and asymmetric light pattern designs. Other standards met include IEC, CIE and IES. Table 5 shows the AOC Streetlight meeting the IEC lighting standards and cut-off luminaire specifications.
The AOC street light uses a unique design which integrates optical, thermal, power and electronic parts in single unit, which ensures reliability and water-resistance (IP65) while allowing easy installation and maintenance.
The AOC unit provides an optimized modular design heat sink of which temperature variation across the heat sink is less that 2°C. In addition the junction temperature of the LEDs is controlled so they are less than 75°C when operated at an ambient temperature 30°C in a still-air situation. Therefore, the lifetime of the LEDs is guaranteed up to 50,000 hours.
The streetlight is available in two colour temperature versions, 5200K and 3000K producing 5280 and 4320 Lumens respectively.

Light and Buidling 2008 did not disappoint with a large number of exhibitors demonstrating new LED based lighting products. The event introduced several new high brightness, high efficient white LED manufacturers to the market and the first energy efficient white LED downlighters that offer a true alternative to CFL equivalents which use less energy and provide more lux.
In 2010, if the current LED trends continue at the same pace then the majority of exhibitors will be demonstrating LED products and visitors will find it increasingly difficult to find Halogen or CFL products on show!
Overall the event was excellent, however it was so large that you will need at least two years to plan your stand visits in advance – book your hotels and buy a comfortable pair of shoes now!


Figure 1: The 20W Amotech high power LED on show at Light and Building 2008

  • Table 1: Technical Characteristics of Amotech high power LEDs

  • Figure 2: The Citizen CL-L220 high power LED efficiency and lumen output graph

  • Table 2: The new Citizen High power, high efficiency general lighting LED range

  • Figure 3: The new Uno Warm White High CRI LED array

  • Figure 4: The Evolution LED adjustable downlighter from ACDC

  • Table 3: The Lighting Performance data of the Evolution LED downlighter

  • Table 4: The Lighting Performance data of the IST LED downlighter (datasheet & operational)

  • Figure 5: The IST white LED downlighter; twice as efficient as a CFL equivalent fixture

  • Figure 7a: Thermal images of the IST LED downlighter highlighting the maximum temperatures (see also 7b)

  • Figure 7b

  • Figure 6a: IST LED downlighter Lux levels

  • Figure 6b: ... versus a twin CFL equivalent

  • Figure 8: The new Martin Exterior 200 LED luminaire

  • Table 5: AOC Streetlight meeting the IEC lighting standards and cut-off luminaire specifications

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