Tag Archives: COB

Tero Explains: What is EPREL for light sources? 2/3

The first article of this 3-part blog post series was dealing with the near-term history of European directives and regulations related to energy efficiency and different energy-related products (ErP), not only energy-using products (EuP).

Starting from Kioto 2005, this process has then proceeded to the situation, where new kinds of regulations have been taken into use, concerning many energy-related products, the latest of those being light sources.

Since 1st September 2021, the insertion of light sources into the EPREL (European Product Registry for Energy Labelling) database has been possible officially. Some problems have occurred in the technical insertion process and also in decisions over which component is a light source and which component is not. The term ’light source’ is defined in the European Commission Regulation EU 2019/2020 laying down ecodesign requirements for light sources and separate control gears (Single Lighting Regulation, SLR).

In this blog post, you can learn how light sources are categorized and what this categorization means in each case.

Categorizing the light sources – is the light source removable or not?

I shortly presented the terms of ’containing product’, ’light source’, and ’separate control gear’ in my earlier blog post in this series. SLR requires that the light source and separate control gear are removable so that the luminaire/fixture can be called the containing product. If not removable, the whole fixture itself has to be regarded as a light source.

Here starts the categorization. I concentrate on light sources in this post. The easiest case is a containing product without a light source: Not Applicable (it is just an empty luminaire body that has no light source included). The second easiest case is the LED lamp that you can buy from a retail store. Then it is not containing a product but only a light source. The sales package in store should include an energy label and other information defined in SLR regulation. Additionally, the lamp information should be added to the EPREL database.

Then let’s proceed into the case(s) where containing product includes the light source.

The first question is that is the light source itself removable? If it is, then it has to fulfill light source requirements defined in Ecodesign/SLR regulation. It is enough that the light source is removable from the containing product without breaking the light source. The containing product is allowed to still deteriorate in that case, but not the light source.

Then there is the next case. If the light source is NOT removable without breaking it, then the whole lighting fixture is considered a light source. The sales package of the containing product has to include an energy label and also other information defined in SLR regulation.

So, the key point is the question, is the light source removable or not? The question, is the light source replaceable or not, is not relevant otherwise than for the end-user that is you or me, a consumer. The supplier (or manufacturer) has to inform in their technical representation, why the light source is not replaceable. This technical documentation should also include information that “this containing product includes a light source the energy efficiency class of which is X”. X can vary from A to G in the new energy efficiency classification. Light source information together with the energy efficiency class must be found in the EPREL database.

Requirements defined in SLR/Ecodesign Regulation

There are several requirements defined in SLR/Ecodesign regulation. These are:

  1. Energy efficiency requirements
  2. Functional requirements
  3. Information requirements (markings)

Energy efficiency requirements

First of all, energy efficiency requirements demand that power consumption of a light source can’t exceed Pon,max (W), which is defined for different light sources in the 2019/2020 SLR regulation. Pon,max depends on many parameters, some of them are real and measurable values and part of them are computational values or factors/multipliers. Computational values are based somewhat ”loosely” on the real world.

If you measure for example your LED board/module in the integrating sphere, and the light source is defined as a non-directional light source (NDLS), you can use all lumens that you measure in your sphere as useful luminous flux (term defined in SLR regulation). If you have a directional light source (DLS), the regulation defines which portion of light you can use for this directional light source. Usually, the measurement for the DLS light sources is better to carry out with a goniometer that can measure light intensity at different angles unlike with integrating sphere which collects all the light rays and integrates them for the spectrometer through an optical fiber.

This relates essentially to EPREL energy class information because you define the energy class according to the following equation:

hTM = (Fuse/Pon) x FTM

where hTM is total mains efficacy, Fuse and Pon are LED parameters (useful luminous flux and power consumption of the measured LED board, COB LED, or any other light source) that are measured from the light source and FTM is a multiplier that is 1.00 for mains light source (MLS, e.g. AC LED) and 0.926 for the non-mains light source (NMLS, e.g. LED board that needs a separate control gear for operation).

The updated measurement software can calculate hTM value directly when you first choose in the software, is your light source NDLS or DLS, and is it NMLS or MLS light source. So spectrometer first measures luminous flux and power consumption and calculates LED luminous efficacy, and then by using a correct multiplier for your light source, calculates total mains efficacy that defines the energy class. For example, in the case of an LED board with separate control gear, this multiplier is 0.926 (see the previous paragraph). Then you can add your LED light source to the EPREL database by filling in all public information, and the EPREL database creates the final energy label for your light source. For market surveillance, you have to add also other technical information, that is not publicly available for everyone.

Functional requirements

Then there are functional requirements. They include many parameters that also depend on the used control gear (LED driver in our case).

  • CRI index ≥80 (outdoor and industrial applications are the exceptions)
  • Power factor cosf (certain limits, depending on the control gear used)
  • Lumen maintenance factor (LED and OLED light sources) àbased on L70B50 value in hours
  • Survival factor (LED and OLED light sources) àrelated to the lumen maintenance factor
  • Color consistency (LED and OLED) àhas to be MacAdam 6-step or lower
  • Flicker PstLM (LED and OLED), depends on the control gear à PstLM≤1.0
  • Stroboscopic effect (LED and OLED), depending on the control gear à SVM value≤0.4

Two last values are defined at full load condition.

Information requirements (markings)

Finally, there are information (marking) requirements.

The surface of the light source itself (not package marking):

  • Useful luminous flux (lm)
  • CCT/Correlated color temperature (K)
  • For directional light sources (DLS), also radiation angle (°)
  • Depending on the size of the light source, the priority is 1) Luminous flux, 2) CCT and 3) radiation angle.

Packing information:

For all light sources, which are sold separately in an independent packaging (but not in a containing product) through a point-of-sale, there are several requirements regarding the packing information. Some of these are mentioned below. It is to be noted that the three first ones shall also be marked on the surface of the light source, given that there is space for all three.

  • Useful luminous flux (lm)
  • CCT/Correlated color temperature (K)
  • For directional light sources (DLS), radiation angle (°)
  • Electrical interface details
  • L70B50 lifetime (hours)
  • On-mode power (Pon)
  • Standby power (Psb)
  • Networked standby power (Pnet)
  • CRI/Colour rendering index
  • Indication if CRI<80 (note; the application must allow it)
  • Indication if the light source is designed for non-standard conditions
  • Warning sign, if dimming is not allowed or can be realized only with specific dimmers
  • Warning sign, if the light source contains mercury

As an alternative to text, the information can also be given in the form of graphs, drawings, or symbols. Besides this information, the packing must show the energy label.

If a light source is being sold as a part of containing the product (and the light source is removable), the requirements are different. In this case, there can’t be any energy label on the containing product packaging. The packaging must indicate the following:

  • Information on whether the light source is replaceable or not, must be shown on the packaging (in the case of end-user sales) or on a free-access website
  • Information if the light source can be replaced only by a professional

As an alternative to text, the information can also be given in the form of graphs, drawings, or symbols.

Conclusion

This is what SLR is in a nutshell. And how you define energy class for your light sources. For printing the label from the EPREL database, you can ask help from the EPREL help desk or your local officials.

In the third, and the last, article of this blog post series, we concentrate on the effects that these regulations may set for the whole lighting industry. As you can see, many parameters depend also on the driver/control gear that is used with the light source. How this affects the component (light source and/or control gear) selections to make genuinely Eco-designed containing products, this we will discuss in the last part of this series.

If you have any questions, you can email me at tero.nurmi@light.fi.


Environmentally Friendly LED Lighting Components

Generally, we can say that LEDs are environmentally friendly and recyclable. They have a long lifetime and low power consumption. They don’t contain hazardous substances, for example, mercury as compact fluorescent lamps do. In this blog post, I will present to you four environmentally friendly luminaire component choices.

LED That Don’t Need a Driver

Have you ever looked inside the driver? In the picture above, you can see the inside of the small-sized one. Drivers are made of many different materials and components. That’s why they are hard to recycle. The fewer components product has, the easier it is to recycle. For example, an aluminium heatsink is easy to recycle, because it contains mainly aluminium.

Drivers are the most fragile parts of the luminaire. In general, they can be the first component that breaks from the luminaire.

All traditional LEDs needs a driver to work. Except for AC COB that can be connected straight to the mains power. Because AC COB doesn’t need a driver, luminaire can be a lot smaller than before. This gives more flexibility for the design. At the same time, you can save in logistics and packing. You can read more about AC COB from our blog post.

Same Lumen Output with a Smaller Luminaire

Size is an important feature when designing environmentally friendly luminaires. When you use less material the luminaire gets smaller. And by downsizing the luminaire you can save in logistics and packing.

One great way to make the luminaire smaller is Citizen’s HC COB. It has higher efficacy and lower terminal resistance. This means that you can use a smaller heatsink. Therefor luminaire gets smaller the and you can still get the same lumen output. As a result, it makes HC COB more environmental choice. Read more about HC COB from here.

The Right Amount of Light and Less Light Pollution with Right Optics

When we talk about LEDs, often we come up with light pollution. We can say that almost all outdoor light that doesn’t have a purpose is light pollution. This means that light always needs a target.

When you replace the old light sources (for example HPS-lamps) with same powered LED, you get a lot more light. This is not environmentally friendly. You get a lot of unnecessary light and same time create light pollution.

When we design luminaires with the same lumen output than before, LED saves energy. This is because LED has less than 10% of the incandescent lamp’s power consumption. That’s why it is important to think about lumens, not power when replacing lamps with LEDs.

LEDs light comes from a very small area and from a flat surface, so it is easier to control than a light bulb. In street lights, most of the light pollution comes from light that goes up and away from the road. It is important to choose optics for the luminaire which are designed to minimize the light pollution.

Control the Luminaires with Sensors

There’s a lot of different sensors for different applications. The most familiar ones are the on/off-sensors. They automatically switch the light >on and off  by movement. They save energy, as the light can never be accidentally left on. This type of sensors is already generally used in public spaces.

Another great way to save energy is to use daylight sensors. They react to the light that comes from the outside. This way you can maximize the benefits of the sunlight. For example, during the day, you don’t need as much artificial light as in the evening. Read more about sensors from this blog post.

We have already made big steps in ecology, but still, we have a lot to do. We need to think about the packing of the luminaire and logistics. It’s important to minimize the amount of plastic used in packing. Also, we need to think alternatives for air freight. Small choices really matter.

Below you can download a presentation about Citizen’s AC COB. If you have anything to ask, you can always email to me: taru.matikainen@light.fi

Download Here

Million shades of white LED

Nowadays LEDs have great efficacy and lifetime. They produce more and more light with less power. I think that it’s less important to increase efficacy because we have already reached what the market demands. What else we need from the light than a lot of lumens? In this blog post, I’ll compare the differences between white LEDs.

We all know that LEDs are available in different color temperatures. For example, Citizen 6 generation’s LEDs are available from 2700K to 6500K. They are also available in different color rendering indexes. Color rendering index simply means how well a white light source can show, or render, colors compared to sunlight. We know that the color rendering index does not always tell the whole truth (You can read more from this blog post).

Nowadays we need a light source that has good efficacy and color rendering, and it doesn’t hurt if the light source can be customized to use in many different luminaires. We want light source that brings colors vivid and alive. Also, design interiors with relaxing atmosphere.

Let’s look into what else affects the quality of light than the color rendering index and color temperature.

White without greenish tone

IMAGE: Black line in the picture is B.B.L. Red circles indicate below B.B.L. LEDs.

In some projects, we want a light source that makes white look whiter. Some LEDs may turn white into light green. Traditional white LEDs’ color temperature chromaticity is on or very near B.B.L. (Black Body Locus). Citizen also produces below B.B.L. LEDs. Their color temperature is below the B.B.L. line. As you can see in the picture, above the line is greenish colors and below the line is reddish colors. Below B.B.L. LEDs make white look pure white and it also renders red colors better. This way we can create light that doesn’t have a greenish tint.

Below B.B.L. LEDs are very popular in shop lighting and everywhere where brisk atmosphere is needed.

Read more about the color temperature from this blog post.

More attractive display with high color contrast

The general color rendering index (CRI) is defined as an average of the sum of first eight R-values. However, these first eight indexes are rather less saturated colors, while indexes R9-R12 represent highly saturated colors. This means that the same CRI doesn’t mean same color rendering.

The Citizen’s Vivid LEDs make colors seem brighter with better color contrast. The spectrum of light has been designed to have as good as possible saturation. This way Vivid LEDs can render bold colors vividly. With better saturation, you can read easier for example newspaper under the Vivid LEDs.

Below you can see a picture where Vivid LEDs are compared. The higher the bar is, the better the color renders. The comparison is done to halogen bulb (0= halogen bulb performance).

Great use for Vivid LEDs are places where good color rendering and concentration is needed, for example, clothing and cosmetic stores, art galleries, schools, hospitals, and offices.

There are two different Vivid LEDs:

  • Brilliant Vivid – Very high color contrast.
  • Natural Vivid – High color contrast.

Vivid LEDs are meant to be combined. Use Brilliant Vivid as spotlights to bring color and textures up, and Natural Vivid as base light because it has better efficacy but has still very good color rendering and contrast.

Change the color temperature of light

Everyone is now talking about “human-centric” -lighting in the lighting industry. It means that by changing the color temperature you can maximize productivity and improve concentration or create comfortable atmospheric feeling. Citizen’s Tunable White is a great solution for “human-centric” -lighting. Its color temperature can be changed freely from 2700K to 6500K. This means that you can achieve warm light like incandescent lamp and daylight with only one module. In addition to changing the color temperature, you can also dim the brightness.

Early Tunable White products have been big sized modules. Citizen’s Tunable white is as small as the COB. This means that you can make a lot of smaller Tunable White luminaires than before. The small size also gives more even light. The spots between cool and warm dies are practically invisible, which guarantee more smoothly light.

By connecting Tunable White into the right control unit, you can change the color temperature and brightness according to the time of day.

Light that gets warmer by dimming

One of the features of the halogen lamp is that when dimmed its color temperature changes warm-toned. Citizen’s Dim-to-Warm COB-LED does the same thing.

Dim-to-Warm is a COB-LED, so you don’t need any complicated special features from the driver, like two-channeling or programming features. Ordinary triac dimmable driver is enough. Dim-to-Warm COB has preset dimming curve, so when you dim it, its color temperature changes automatically just like halogen.

I hope that this blog post gives you some new thoughts for designing the luminaires. When you use any of the LEDs that I just presented to you above, you’ll get a luminaire that has more to provide than just ordinary light source. This way you can have competitive advantage.

You can download presentation about Citizen LEDs below. If you have anything to ask, please do not hesitate to contact me. My email address is taru.matikainen@light.fi and I’m always happy to help you.

Download Here

Why Heat Pipe is Better than Traditional Heat Sink?

You will need a heat sink when you use a COB LED in your luminaire. The traditional way of transferring the heat away from the light source is to use a passive aluminum heat sink. In this blog post, I’ll introduce you the new way of cooling: heat pipe.

Traditional heat sinks are based on the fact that aluminum transfers heat away from the light source. The higher the power of the LED is, the more you need aluminum.

This grows the luminaire’s size and makes it more expensive. The bigger size of the luminaire makes logistics costs go up and increases the price for end user even more.

We have a better solution for cooling high power LEDs without the need for noisy fans or heavy heat sinks.

Furukawa Heat Pipe (HYC Series)

Heat pipe technology is traditionally being used in computers and for example in satellites. But now it is available in lighting.

Furukawa HYC Series uses heat pipe technology to transfer the heat and makes heat sinks more efficient in cooling the LED.

how heat pipe works

Its thermal conductivity is almost 200 times better compared to copper. This also allows the heat sink to be a lot smaller than we are used to.

Smaller heat sink reduces the weight of the luminaire dramatically. This reduces transportation costs as well as the amount of other materials needed.

The Heat Pipe effectively transfers heat from the heat source and as a result makes the cooling faster than ever.

Unlike many Chinese manufacturers, Furukawa uses oxygen-free copper in its Heat Pipes, which means that their lifetime is over 20 years.

Heat Pipe vs. No Heat Pipe

Cooling with and without the Heat pipe

Save Money and Environment with our aLED Light Engine

aLED Engine

aLED Light Engine (Furukawa Heat Pipe + Citizen COB + optics + aLED Driver)

As a great example, I want to introduce you our own aLED Light engine that uses Furukawa heat pipe with Citizen COB. aLED Light Engine produces over 40 000 lm and weights only 1kg (without driver and optics). And only 3.6kg with optics and driver.

By combining Citizen COB and heat pipe technology, you can build luminaires that:

  • Produce a lot of light
  • Are light in weight and small in size
  • Save environment
  • Are completely recyclable

Furukawa Heat Pipes are compatible with Citizen CLU04x and CLU05x COB LEDs.

Download an example of different combinations and datasheets for custom models with screw holes for Citizen COBs.

Download Here

How to Connect a Single LED Component into AC Network

I have two blog posts for you focused on how you connect COB LED components into the electrical network. I mean, when you have either a single COB LED or an LED module based on SMD LED components assembled on a PCB board.

Compared to traditional lighting, connecting LEDs to the electrical network is a whole new world. LEDs need direct current (DC) to light them, alternating current (AC) will not work. There are also AC modules available but those are not covered here.

In this post I will concentrate on connecting single COB LEDs. In case you are interested in connecting LED modules, I will write about that in my next post.

LED driver

You will need an LED driver, which is actually an AC/DC converter. It converts the AC voltage/current of the electrical network into the suitable DC voltage/current needed by the LED component. You will find the requirements of the LED from a datasheet provided by the manufacturer. If you need help in choosing a driver, you can read our guide.

Figure 1. Example of an AC/DC converter, LED driver. This one is from ELT with dipswitches, which means that you can choose the driving current.

Connecting COB LED into the AC network

In case of COB, you will have to create a closed electrical circuit so that the electrical current can flow through the LED component. A COB LED is basically a diode in its electrical nature: the current can flow only in a forward mode. This means that you must connect the positive (+) solder pad of the COB LED into the positive terminal of the LED driver. In the same way, you connect the negative (-) solder pad of the COB LED into the negative terminal of the LED driver. See the Figure 2 below.

 

This way, you create the closed electrical circuit that is needed to feed current through the LED so that it gives light. This closed electrical circuit formed by the LED driver and the COB LED is called the secondary side of the LED driver. LED driver feeds the power and current into the closed electrical circuit, and thus through COB LED, on the secondary side.

 

Figure 2. COB-AC Network

 

On the primary side, the LED driver gets electrical power from electrical network, AC network. The terminals of the LED driver on the primary side are called line and neutral. They are connected into the line and neutral connections of the AC network. If you have an LED driver with cables, they are usually blue (neutral) and brown (line). Some drivers also have a ground terminal, which is usually connected to the luminaire body with grounding wire. However, the closed electrical circuit is needed also on the primary side; between the network and the driver.

Usually, you will need to use some kind of terminal block to connect the driver into the electrical network on the primary side.

Picture of a terminal block

Figure 3. The example of terminal block to connect the LED driver into the electrical network.

Two options

Finally, as for physically connecting a COB LED into the LED driver, you have two ways to do it:

  1. solder the wires on the solder pads of the COB
  2. use solderless connectors.

In the first method, you manually solder the wire by using soldering iron with high temperature that melts the soldering material such as tin. After cooling, there is a joint between the wire and the COB solder pad. You need two wires, one for plus and one for minus solder pad.

In the second method, you use a solderless connector.

Figure 4. The solderless connector.

The solderless connector does the same effect as the soldered wire. You need the electrical connection also in this method, but you won’t need to solder the wire by melting tin. You just push the wire into the push-in terminals of the connector. Again, positive to positive and negative to negative terminal. They are marked on the connector. Basically these push-in terminals work with a combination of metal plates and springs that then make the connection to the solder pad of the COB LED.

The difference between these methods is, that unlike with soldered joints, in the solderless connector method the springs may loosen a bit over time and loss of contact may occur. Solderless connectors are generally thought to be more expensive than manual soldering.  

In my next post I will go through the steps for connecting LED modules.

Thank You for Everyone at Elfack 2017

I would like to thank everyone who we met at the Elfack Exhibition in Gothenburg, Sweden.

We had some good conversations with our existing customers as well as new people. This year we tested the color quality of Citizen’s LEDs at our stand. We got many answers through our questionnaire and found out that many visitors were excited about this new way of lighting.

If you took part in the test, you will receive the test results soon. We will also share these results with the public a little later.

We had a chance to show you our new products and the feedback we got from you was very encouraging.  I went through all the products in my last blog post, and if you wish to download more information about them, you are most welcome to do so here.

The products displayed at Elfack include:

  • aLED Engine
  • Citizen Gen 6
  • AC COB
  • Citizen Vivid Series
  • Furukawa Heatpipe
  • Merrytek sensors
  • Letaron & aLED Drivers

Our personnel will contact you as agreed, if they haven’t already. In case you have anything to ask, you can contact us directly.

 

What We Are Presenting in Elfack?

Elfack exhibition will be held in Gothenburg, Sweden from 9th to 12th of May. As it has been with previous exhibitions, we will be releasing new products and presenting the latest technology at our stand.

This year we will introduce and present the following products at our stand F04:70.

aLED Engine

aLED Engine

aLED Light Engine

We designed aLED Engine for applications that require a lot of light. aLED Engine consists of Furukawa heat pipe and Citizen COB LED.

In addition you can also choose a suitable optics and LED driver for the light engine from our selection. Suitable drivers are available as on/off, 1-10V dimming and DALI dimming.

aLED Engine is also compatible with Merrytek sensors, which allow you to control the lighting as you wish.

The 300W engine produces 36.000 lm at 4.000K and weighs only 3,6 kg with a driver installed.

aLED Engine will be at our stand in Elfack. There you can see the engine in action and try it with a daylight sensor.

Download More Information

Furukawa HYC Series

Furukawa HYC Series uses heat pipe technology to transfer the heat and makes heat sinks more efficient in cooling the LED.

how heat pipe works

How Heat Pipe Works

Heat Pipe’s thermal conductivity is almost 200 times better compared to copper. This allows the heat sink to be a lot smaller than we are used to.

Smaller heat sink reduces the weight of the luminaire dramatically.

The heat pipes effectively transfer heat from the heat source throughout the whole heat sink cooling the heat source faster than ever.

Heat Pipe vs. No Heat Pipe

Heat Pipe vs. No Heat Pipe

Furukawa heat pipes are compatible with Citizen COBs.

Furukawa heat pipes will be at our stand so you can see and try how light they are.

Read more about Furukawa heatpipe from here.

aLED & Letaron Drivers

aLED Driver

aLED Driver

aLED and Letaron offer a versatile range of both constant current and constant voltage drivers from low to high power (from 1 W up to 600 W).

Ouw own aLED drivers are best suited for high power applications. They are all available in IP68 and can be ordered as on/off, 1-10V dimming or DALI dimming.

Letaron drivers are best suited for low power applications, although they are available up to 52W.

Letaron offers a variety of designs to suit your needs including round, rectangular and slim models.

The Letaron low power drivers are also compatible with OLED light sources.

aLED and Letaron drivers will be on at our stand so you can see and try them yourself.

Merrytek

Merrytek sensors

Merrytek offers a wide range of different sensors. Some sensors come with LED driver and some are independent and can be connected to LED driver.

Merreytek has products particularly designed for eg. homes, schools, stairways, warehouses, offices, parking garages and outdoor use.

Merrytek’s intelligent lighting control products include:

  • Microwave motion and daylight sensors
  • Dimmable LED drivers
  • LED drivers with intergrated sensors

There will be Merrytek products on display at our stand. We will have an aLED engine wiht Merrytek’s daylight sensor on our stand, so you can see how it functions.

Citizen Gen 6, AC COB &Vivid Series

Citizen released Gen 6 COB and AC COB earlier this year with improvements compared to the previous versions.

Thermal Resistance

Thanks to better heat resistance, you can use much smaller heat sink. Gen 4 on the left, Gen 5 on the middle and Gen 6 on the right.

For the new Vivid series we’ve prepared a demo wall at Elfack for you to examine the possibilities of color quality control in LED lighting.

Seminar about color quality

We will organize a seminar about color quality on the first day of the exhibition.

Color comparison Vivid COBColor Comparison Regular COB 3000K Ra80 vs. Vivid Brilliant

The seminar will take place on Tuesday 9th of May.
Time: 16:00-19:00
Place: Hotel Gothia Towers, Tower 1, meeting room R22-23

The program:

  • Doors open at 16:00
  • Coffee
  • Welcome / Arrant Light Oy by Janne Mäkinen, Managing Director / Arrant-Light Oy
  • Color Quality with CITIZEN by Kosuke Tsuchiya, Field Application Engineer / Citizen Electronics Co.
  • Demonstration and open discussion
  • Refreshments and snacks
  • Close at 19:00

Please sign up for the seminar as soon as possible or latest by April 30th. We have limited seats and there is room for the first 20 persons only.

Sign Up for Our Seminar

Welcome to visit our stand F04.70 at Elfack.

All datasheets and other material will be available from our website soon. If you wish to download material about these new products before the exhibition. You can do that here.

AC COB – Easier way to make a luminaire

What is AC COB?

AC COB is brand new AC LED solution from Citizen Electronics. It is available with holder which contains necessary components to connect package directly to mains voltage. So basically it is designed to make life of luminaire manufacturer easier.

AC COB With Connector

AC COB With Connector

What advantages?

AC COB has integrated circuit which allows you to control luminous flux more accurately. For all CCT and CRI versions you are able to have exactly same luminous flux from the package e.g. 750, 1000, 1500 and 2000 lumens.

5 volt output enables you to use e.g. motion sensor, so you can easily adapt external sensors to easily add features to your luminaire.

There is no additional losses from driver and so there is no problem to have good efficacy even with low powers. AC COB with new integrated circuit has good compatibility with dimmers, you are able to dim this solution with Triac (leading-edge) and Transistor (trailing-edge) dimmers.

Small form factor and no need for external driver allow even more creativity to luminaire design. There is no need to worry where to place the driver.

What you need to take to consideration?

AC COB has of course similar characteristics than normal COB meaning warmer CCTs have lower efficacy than cooler CCTs. With fixed luminous flux, that means you have difference in power. So 2700K Ra90 AC COB consumes more power than 5000K Ra80.

And of course AC is still AC. If you don’t use more complex circuitry to modify AC to DC, you will still have AC characteristics affecting luminous flux. Mainly with AC LEDs this means that you have flicker present in light source. To reduce that effect, it is good to consider e.g. secondary optics which lower this phenomenon.

AC COB In Connector

AC COB In Connector

Conclusion

Even though AC LED might have it’s limitations it has certainly some advantages which make it viable solution as light source. It has ENEC certified components which are easy to use to design new luminaires and you can make testing with this solution in different luminaires. Now it is time to consider where you could use AC COB to realize its advantages.

You can download datasheets and brochure from the button below.

Download Here

Vivid LEDs: Special Color Rendering With Spectrum Tuning

When we talk about color rendering, traditionally that conversation has been filled with CRIs and Ra-indexes. These traditional ways of telling how well certain light source represents sunlight have been criticised because they may not tell the whole truth.

In recent years, LED manufacturers have been trying to answer this criticism by creating different products. Terms like “premium white”, “crispy white”, “pearl white” and “vivid white” have come to LED markets.

Despite the different terms, they are all meant for the same purpose: To represent certain colors and make the lighting look better. I will be using term “Vivid” as it is the term Citizen Electronics uses. And to be honest, it describes the purpose of these LEDs quite well.

Color rendering

Color rendering means simply how well a white light source can show, or render, the true colors of different physical objects compared to sunlight. You know the effect when you buy a jacket in the clothes shop and it looks completely different in sunlight.

Colors are divided into 15 indexes (R1-R15). A general color rendering index (CRI or Ra-index) is defined as an average of the sum of first eight indexes (R1..R8). However, these first 8 indexes are rather less saturated colors, while indexes R9-R12 represent highly saturated colors (red, yellow, green, blue).

CRI 100 = Sunlight

For example, in grocery stores, a shopkeeper may want to highlight red color of meat or colors of vegetables. This means that the general color rendering index doesn’t really tell anything about the rendering capabilites of the light. In this case, high rendering index of some of R9-R12 indexes is necessary. It doesn’t matter how high the CRI is, R9-R12 can be anything.

CRI 83 (look at R9)

CRI 83 (look at R9)

The above image shows the index values of R1-R15. The CRI is 83, but look at the R9 value. Not very good.

So basically, the LED itself can have the CRI of 97 and you still have no idea how does it render red or green for example.

Vivid via Spectrum tuning

Vivid LEDs are made using spectrum tuning. In short, this means that the phosphorus of the LED has been modified. How it is modified, depends on the LED and the intended application. Note that spectrum tuning can be made also by using RGB-LEDs.

For example, Vivid White LED’s spectrum has been tuned so that it represents white and bright colors as well as possible. The colors are more saturated than under typical normal LED light.

Test report on Vivid White aLED Module

Test report on Vivid White aLED Module. Click the image to open it in new tab for better view.

These LEDs work very well for example, in clothing stores, where you have a lot of different colors that need to look good.

Here are two good principals when choosing LED:

  1. Think about your application, what colors do you want to highlight?
  2. Don’t stare at the CRI (unless you get a full report), it might not tell everything

Conclusion

Traditional way of thinking color rendering solely through the CRI should be updated. More importantly, you should know what you want to highlight and ask for a LED suited for your application.

Download More Information About Vivid

 

What is COB LED

COB LEDs are very popular nowadays in LED lighting business. We talk and write about COBs, and our customers use COBs in their luminaires, but what exactly is COB? First of all, the abbreviation COB comes from words Chip-on-Board.

Citizen COB frontside, The yellow substance is phosphor, which turns the blue light of the chip white

Citizen Electronics’ COB frontside, The yellow substance is phosphor, which turns the blue light of the chip white

In COB packages many LED chips are usually attached to substrate with non-conductive adhesive. LED chips are wire bonded together to make different LED setups. The amount of single LED chips, inside a one COB LED package, can vary from few pieces up to several hundred pieces. Substrate is located on base material. Base material of COB LED is usually MCPCB or ceramic PCB. COBs often have blue diodes and use yellow phosphor layer to convert light to desired color temperature.

 

General drawing of a COB LED.

General drawing of a COB LED.

In early years of 21st century there were few SMD LED packages, which could be considered almost as COB packages due to their construction. Generally COB LEDs became available and popular in LED lighting market around year 2007. At first there were first quite a lot doubts towards COB LEDs in the market . Mainly because this package construction enabled LED manufacturers to put high powers in small package. Over then, this “high power” meant over 10W,

Also there was very little experience of COB LEDs, so these LEDs had a lot to prove.  Although now several lifetime tests have shown that COB packages are very reliable, if heat management is done properly.

When thinking about heat management, one important feature is thermal resistance. But it is worth noticing, that you can’t define which COB LED is better to conduct heat just from thermal resistance value. You should actually test LEDs in your own application.

Today COB LEDs are available from few hundred lumens up to 30,000 lumens. This means that

Citizen COB backside, aluminium PCB, which will conduct the heat to the heat sink effectivily. However it won't be enough to cool the LED

Citizen Electronics’ COB backside, aluminium PCB, which will conduct the heat to the heat sink effectively. However it won’t be enough to cool the LED

almost every light source can be replaced with COB LED. So available powers go from few watts up to almost 200 watts. The most powerful COBs require exessive heat sinks because they generate a lot of heat.

COBs offer great variety due to possibility to have many different LED setups even inside one COB package. Usually LED manufacturers have different lumens packages available in same size COB, so lighting manufacturers is able to use e.g. same connectors and optics in different solutions. Also it is good to remember that usually you can underdrive or overdrive COB LEDs and those might have quite wide driving range. This allows you to drive LEDs with very high efficacy, you can make balanced solution or you can make economical lumens.

COB LEDs are generally used in luminaires where lamp or single spot light sources have been used. So basically COB LEDs are used in almost every kind of luminaire. Although COB LEDs are used less often in linear lights or  panel lights, some solutions of that kind have been made with COBs. Luminaires which have really high luminous flux are usually made with more than one COB LED to distribute heat flux and to ease design of heat sink.

Sochi Olympic cauldron, Lights made using Citizen COB

Sochi Olympic cauldron, Lights made using Citizen Electronics’ COB (Copyright: Zers Pride LLC)

COBs offer very high luminous fluxes from small size packages and thus allow flexible design of luminaire. This gives you more freedom, when designing a luminaire. COB packages usually have excellent uniformity of light from light emitting surface, this is important e.g. if you want to avoid multiple shadow effect, which might occur with SMD based solution. It is also very easy to test COB LEDs. You only need COB LED, constant current driver and e.g. piece of aluminium, which can be used as heat sink.

LED Shadows: On the left, a shadow from a COB. On the right, a shadow from a LED with multiple light sources

LED Shadows: On the left, a shadow from a COB. On the right, a shadow from a LED with multiple light sources

We can see that COB LEDs have been very important development step in LED lighting business. This great package design has allowed to increase powers used inside one LED package tremendously. Also one good indicator of success of COBs is that today every major LED manufacturer and package maker has COB LEDs in their selection.

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