(Writer:KEN OKAMOTO／Lighting Designer)
The largest lighting exhibition in Asia, Lighting Fair is held once every two years. This year's exhibition is the tenth edition. Past fairs have been held in the East Hall of Tokyo Big Sight; however, this year's exhibition was held in the West Hall because of its expanded scale. For work-related reasons, I was only able to attend for two days, on March 8th and 9th. This year's expanded Lighting Fair was so large that I was unable to visit all the booths that I was interested in. This showed me how much the level of anticipation and interest in energy efficiency and LED lighting has risen.
More than 90% of the products exhibited at the last Lighting Fair in 2009 were LED lighting. Almost all of them achieved brightness as good as conventional lamps which made me strongly feel that the LED era had truly arrived. This year's Lighting Fair was no different in that almost all the products displayed were LED, but this time I did not feel the same feverish interest in LEDs as in the previous Lighting Fair. I don't think that this was because interest in LEDs has waned. It seems to be because, in the past two years, LED lighting has become normal in the building and lighting industry, and normal end-users experience it as an everyday thing. To that extent, people take a more critical view of LED lighting, and a new range of higher expectations and demands are presenting the industry with higher hurdles to overcome.
The following are the keywords of interest at Lighting Fair 2011.
- Straight Tube LED Lamp
- Evolution of the LED bulb
- Seamless LED
- Internal power sources
- Organic EL
The following is my report on Lighting Fair 2011 in which I will discuss actual examples associated with each keyword.
About two to three years ago "multi-shadow" became a word frequently heard in the lighting industry. Multi-shadow indicates the unique shadows created by LED lighting. With normal light fixtures (in particular down lights and spot lights), one lamp is used per fixture. But LED lighting is referred to as an LED package, consisting of a collection of small light emitting parts. Each individual LED package emits light, so most LED lighting is a light fitted with a set of many small lamps. Therefore, when an object is illuminated by an LED light, it is simultaneously illuminated by many small lamps, so unlike a normal shadow, many overlapping shadows are produced. This phenomenon is referred to as "multi-shadow."
Figure 1 This LED light shows how LED packages are fitted onto a single fixture.
Figure 2 Example of multi-shadow
Multi-shadow was one of the disadvantages of LED lighting, but now each lighting manufacturer has started developing fittings that address this problem.
Lights that eliminated multi-shadow were a major feature at the Fair. Most of these fittings are not conventional types that are a set of LED packages. Instead they use an LED module in which light from several LED chips is emitted in a plane using a diffusion plate that contains phosphor. By adopting modules that emit light in a plane, soft, diffused light similar to conventional incandescent light bulbs or fluorescent lights can be obtained. In this way, the multi-shadow is eliminated.
Typical examples of the plane light-emitting LED module are "Fortimo" from PHILIPS (PHILIPS ELECTRONICS JAPAN), and "XLM" and "XSM" from XICATO JAPAN (XICATO). Among the major lighting manufacturers, KOIZUMI LIGHTING TECHNOLOGY and YAMADA SHOMEI LIGHTINHG adopt the PHILIPS Fortimo module. YAMAGIWA and others adopting the XICATO XLM and XSM modules have developed light fittings that have eliminated multi-shadow.
Figure 3 The PHILIPS Fortimo LED Twistable Module
Figure 4 Modules can be simply fitted and removed by using a dedicated socket.
Figure 5 Removing an actual module
Figure 6 XICATO's XLM module and the XSM module (at the YAMAGIWA booth)
Figure7 A comparison of conventional LED (left) and Fortimo (right), which eliminates multi-shadow
Figure 8 Light fittings offered by each of the manufacturers that have adopted XICATO modules (XICATO booth)
Figure 9 Various manufacturers have adopted the XICATO module as their partner in light fittings.
It might sound easy to eliminate multi-shadow by spreading LED light with a diffusion plate, but the problem is not so simple. The quantity of light from each individual LED package (or LED chip) is certainly not large. When the light is spread with a diffusion plate, the efficiency drops greatly, and it is not possible to obtain sufficient brightness. If LED power (electricity consumption) is increased to solve this problem, the heat generation becomes large, and dissipating the heat becomes difficult. Heat has various adverse effects, including reducing the life of the LED. With the advent of modules that solve these problems, it has become possible to eliminate multi-shadow. These modules are units from which the light emitting part can be removed. When the performance of the LEDs improves, existing LEDs can be replaced with new units.
Figure 10 Down light from KOIZUMI LIGHTING TECHNOLOGY using the PHILIPS Fortimo LED Twistable module (cledy series)
Figure 11 Down light from YAMAGIWA that uses the XICATO XSM LED module (X-series)
Figure 12 The OPTGEAR series from ODELIC uses plane light emitting Chip on Board (COB) LEDs.
The PANASONIC ELECTRIC WORKS booth and elsewhere displayed lighting that eliminates multi-shadow by adopting a high-power, One-Core LED, which is unlike the plane light emitting module. Compared with other fittings that use plane light-emitting modules, the luminosity is somewhat high, but with sufficient brightness and priced at about 15,000 yen, it offers a cost-performance advantage.
Figure 13 The One-Core LED module from PANASONIC ELECTRIC WORKS
Figure 14 Down lights using One-Core LED modules (PANASONIC ELECTRIC WORKS)
Figure 15 Pendants with the One-Core LED module (PANASONIC ELECTRIC WORKS)
This keyword is related to the advent of plane light emitting modules as represented by Philips and Xicato, which have already been introduced. The number of fittings without the glare (uncomfortable luminescence) characteristic of LEDs has increased. This is thought to be because control of luminous intensity becomes easier by making the light-emitting part a flat plane and by fitting the light emitting part deep inside the fixture. As a result, it is possible to make the shielding angle deeper, as in light fittings using conventional light sources. This reduces glare. The shielding angle is normally the angle within which the lamp cannot be seen within the fitting (mainly down lights) when fitted to a ceiling, etc.
Figure 16 Shielding angle and cut-off line
The greater (deeper) the shielding angle of a light fitting, the narrower the range over which the lamp can be seen. By making the shielding angle large, the feeling of brightness seen as a characteristic problem with LEDs is reduced. There are now many light fittings without an uncomfortable glare, and are not inferior to so-called glareless light fittings that use conventional light sources.
Figure 17 Example of a glareless LED down light using a plane light-emitting module (X-series, YAMAGIWA)
However, by using plane light-emitting modules, some light fittings give the impression that compactness, which is one of the advantages of LEDs, is not being provided. Development work on this problem is expected to progress.
Along with "multi-shadow," the word "retrofit" was frequently heard at the exhibition. Retrofit refers to the modification of old-fashioned equipment into the latest type. In the lighting industry, the word is used to mean using an LED bulb (lamp) as it is in a conventional socket. Until the previous Lighting Fair, LED bulbs used as replacement lamps for incandescent bulbs using E26 or E17 were the main retrofit lamps. However, at this year's Lighting Fair, the use of halogen LED lamps to replace dichro-halogen lamps (MR16) was very conspicuous. LEDs for the line voltage specification (lamps that can turn on at 100V) had been previously developed, but a feature of this Fair was surely the appearance of many LED lamps that can be used to replace 12V 50W low-voltage halogen lamps. Moreover, most of these can be used without changing the voltage with a transformer. I am looking forward to the appearance of more attractive light sources in the future. The power consumption of most of these is 10W or less, and their energy efficiency is a great improvement over the commonly used 110V 40W or 12V 50W dichro-halogen lamps. They are inferior to dichro-halogen lamps in some respects -- in terms of brightness or the spread of light, but my impression was that for spaces with only LED lamps, the quality has been raised sufficiently to eliminate any feeling of discomfort.
Figures 18, 19 DN LIGHTING displayed their dichroic halogen type LED lamps, and their EZ10 and GU5.3 lamps, which can be used as they are with conventional 12V fixtures.
Figure 20, 21 The Philips E11 dichroic halogen type LED (equivalent to 40W)
Figure 22 Among the other LED products on display were 35mm (equivalent to 12V 20W) types offered by PHILIPS.
Figure 23 Products illuminated by a 35mm (equivalent to 12V 20W) dichroic halogen type LED lamp (from PHILIPS)
Figure 24 The PHILIPS MASTER LED Spot: Two EZ10 lamps were on display. One was a 10W type equivalent to a 12V 50W, and a 7W type equivalent to a 12V 35W. Unlike other d dichroic halogen type LED lamp, these are equipped with cooling fans. At the exhibition it was possible to replace an actual 12V dichroic halogen lamp with a dichroic halogen type LED lamp and turn it on.
Figure 25 The E11 dichroic halogen type LED lamp from PANASONIC ELECTRIC WORKS (equivalent to 40W)
Figure 26, 27 The DECO-L (E11 dichroic halogen type LED lamp equivalent to 40W) from DAIKO ELECTRIC, an adjustable type, was also on display.
Figure 28 The dichroic halogen type LED lamp from lamp maker IWASAKI ELECTRIC
Figure 29, 30 The dichroic halogen type LED lamp from USHIO LIGHTING offers size as its main feature. It is almost as large as a 110V 40W dichroic halogen type LED lamp.
Figure 31, 32 STE's booth mainly displayed retrofit LED lamps that can replace conventional light sources with LEDs. Their products were displayed under the DECOLIGHT name. This booth featured many types of retrofit LED lamps on display in addition to dichroic halogen type LED lamp. In the case of dichroic halogen type LED lamp, they sell EZ10 as well as E11. Light distribution types, adjustable light types, and rare 70mm dichro-halogen LED lamps were also on display. One attraction was that the price range was the same as for conventional halogen lamps.
I actually visited a hotel where all the down lights used were dichro-halogen LED lamps like those displayed at this exhibition. The environment created was so natural that initially I didn't notice that they were LED lamps.
Figure 33, 34 An example of a hotel using DECOLIGHT dichroic halogen type LED lamp (E11, equivalent to 40W) (down lights only).
Compared with incandescent LED lamps, it appears that the brightness, light distribution, color temperature, and prices of dichroic halogen type LED lamp vary greatly with respect to each manufacturer. If sold in the price range of 2,000 to 3,000 yen, the same as incandescent LED lamps, then dichro-halogen LED lamps, which originally were 1,000 to 2,000 yen more expensive, would seem to have an edge over incandescent lamps in terms of cost.
Straight Tube LED Lamp
On October 8, 2010, the Japan Electric Lamp Manufacturers Association adopted the standard straight tube LED lamp "JEL 801:2010". This altered the direction of development of straight tube LED lamps by each manufacturer. Major manufacturers such as PANASONIC ELECTRIC WORKS and TOSHIBA LIGHTING & TECHNOLOGY have released straight tube LED lamps complying with this new standard. Some manufacturers at the exhibition displayed straight tube LED lamps corresponding to the existing G13, which has been the mainstream to date. However, I think in the future straight tube LED lamps corresponding to the new standard GX16t-5 will become the mainstream.
Figure 35 Visitors could experience removing the lamps at PANASONIC ELECTRIC WORKS' booth.
Figure 36, 37 straight tube LED lamp with uniform diffusion of light (PANASONIC ELECTRIC WORKS): A high-efficiency diffusion film is used to achieve uniform light diffusion.
Figure 38, 39 TOSHIBA's booth presented a comparison of straight tube LED lamp electrical power consumption and visual brightness with that of conventional fluorescent lights.
Figure 40, 41 ROHM also exhibited straight tube LED lamps complying with the new standard.
Care is required when using a straight tube LED lamp in a conventional light fitting because the socket or power supply unit has to be replaced by a new one.
The standard for straight tube LED lamps defined by the Japan Electric Lamp Manufacturers Association(JELMA) is as follows.
|Total light flux||2,300 lm or higher (N color)|
|Lamp voltage||95V (maximum) to 45V (minimum)|
|Maximum lamp power||33.3ｗ|
|Color rendering properties||Ra80 or higher|
|Light distribution||Light flux within 120 degrees is less than 70%|
Fluorescent lamps complying with the new standard, such as those displayed at the PANASONIC ELECTRIC WORKS and TOSHIBA LIGHTING & TECHNOLOGY booths, have natural light and sufficient brightness, so I expect them to be competitive. A problem with fluorescent lighting is that the light cannot be smoothly adjusted. This is something that LEDs are expected to easily achieve. However, the price seems to be somewhat high. Compared to the 1,000 to 1,500 yen cost of a 40W straight tube fluorescent lamp, a straight tube LED lamp costs about 16,000 yen (in the case of the LDL40S from PANASONIC ELECTRIC WORKS). This is nearly 10 times higher. The life of an LED is about 40,000 hours, or three times that of a fluorescent lamp, and the electrical power consumption is about 30 to 40% less, so the price seems to be high. However, as in the case of LED bulbs which were brought to market and widely distributed earlier, competition among manufacturers is expected to lead to rapid improvements in brightness and light quality and to lower prices. The market for straight tube LED lamps as replacement lamps is as large as that for incandescent lamps, and it is predicted that improvements will proceed at the same pace as those achieved for LED bulbs.
It is thought that the arrival of the straight tube LED lamp will lead to accelerated propagation of LEDs, particularly in office spaces. Square base lights, for office use were conspicuous at the previous Lighting Fair, but at this year's edition, there were many products for offices other than straight tube LED lamps.。
Figure 42, 43 Square base light for offices using LED light guide plate presented by SUMITOMO CHEMICAL (from KOIZUMI LIGHTING TECHNOLOGY booth)