Design signs and displays as true brand promotion assets.

A report covering: Reliability, compliance, industry standards, energy saving practice and latest product

AUDIO APPLICATIONSSIGN & DISPLAY APPLICATIONS

Powering Sign and Display Applications

“© 2017 Sunpower Group Holdings - All Rights Reserved”

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ContentsLight box excellence or installation disaster? 3

Specifying drivers that are suitable for light box applications 3

Specifying LED strips suitable for lightbox applications 4

Meeting safety standards 5

Ensuring safe and reliable lighting component design 6

IP (ingress protection) rating charts 7

Customer perspective 9

Conclusion 9

Icon information 10

PowerLed related products 11

Benchmark 11

How to deliver successful display light box solutionsLED display light boxes create a high impact at an economical price, improving both brand image and sales. While the quality of the printed graphics makes an obvious and critical contribution to this impact, other, less apparent factors also play an essential role. In particular, the lighting and associated power supply components fundamentally influence not only the displays quality of appearance, but also its ability to perform reliably, economically and above all, safely.

So how is it possible to source lighting components that give light box designers and sign makers a competitive edge in a demanding environment, while meeting the many other requirements of a successful retail installation?

In this report we look at these issues – covering not only the points to consider and benefits of sourcing the right LED products but also what can go wrong if poor choices of product or supplier are made.

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Light box excellence or installation disaster? These are the factors that make the differenceThe light box exists for one purpose only: To illuminate the customer’s brand and name. Achieving this excellently and consistently is critical, as any shortcomings will have a strong negative impact wherever the sign is visible. Inferior performance will actively detract from the customer’s brand image rather than promoting it.

That’s why meeting the customer’s expectations for colour, reliability and quality is paramount. We hope that the guidelines below prove useful to sign builders seeking to meet these expectations and guarantee a positive brand experience for their customers and consumers alike.

Quality of light box illumination: The ‘light quality’ challenge is to achieve the right brightness, CRI and colour temperature, while avoiding spotting on the light box surface. Factors to consider include:

- Choosing an LED strip with the right number of LEDs per metre – typically 30, 36, 60, 120 or 180. It is essential to find the correct value for this number, as well as the depth of the lights below the diffuser, to ensure that a seamless light display without spotting is achieved.

- CRI: LEDs are available with a colour rendering index (CRI) of 80, 90 or 95. Choose the highest rating possible, as this will approximate best to a natural light source and enhance the appearance of any illuminated object.

- Choosing LEDs with a colour temperature to suit the objects being illuminated, or to set the desired mood. Available tones include 2500K for a very warm white, 3000K warm white, 4000K neutral or daylight, and 6000 - 6500K for a cool white.

- Light output: Options for optimising colour temperature and achieving colour changing are available, with flexible strips that offer either an integrated white (RGBW) or an additional white LED (RGB+W).

RGBW provides a wider colour mix, while the RGB+W option offers the benefit of colour changing along with a single white where required.

RGB+W options include Warm White LED (RGB+WW 3000K), Neutral White (RGB+NW 4000K), or Cool White (RGB+CW 6000K). This achieves a combination of RGB and a dedicated white tone for all applications.

Maintaining consistency: Tight binning control is essential to ensure consistent LED light tone. Lower cost LED solutions will commonly offer far less control of the LED tone, either between production batches or even within one single production batch. Large tone tolerance will potentially be perceived as a warmer or cooler tone. PowerLed offers tight binning control to suit the customer’s requirements and/or budget.

Specifying drivers that are suitable for light box applicationsDesigning low cost drivers into enclosed environments such as light boxes or signs often proves to be a false economy; early failures can occur as the drivers fail to cope with these applications’. Any failure is immediately obvious to consumers, expensive to fix on site, and damages the reputation of both the retailer and the light box supplier.

PowerLed understands these issues, and offers drivers, including high-power models up to 600W, that provide various design features equipping them well for enclosed environments. Many have had additional heat sinking to ensure excellent thermal management. Superior latch off provides enhanced safety; if a short circuit occurs, the driver will shut down, latch off, and need a manual reset to restart. This is beneficial because it avoids exposing operators and consumers to a repetitive and highly undesirable flashing effect during an unattended power problem. Unwanted power cycling can also create a risk of electric shock, equipment damage and fire.

Additionally, most brands particularly dislike ‘flashing failures’, as they believe they devalue their brand image.

An additional benefit is that the driver also shuts down and must be reset if it draws excessive current or its temperature exceeds preset limits – an important safety consideration.

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PowerLed drivers have further light box-friendly features. These include a low-profile design, which does not cast a shadow when installed within the box, push-fit terminals for faster, easier installation, and wide-range voltage inputs that work with both 240 VAC and 110 VAC (50 and 60 Hz) supplies. Remote dimming is possible using various industry standard control input types; these include 0 – 10V, 1 – 10V, DALI, Triac and DMX.

Drivers chosen for light box applications should be derated, typically to 85% of full load. This ensures reliability in the elevated-temperature environment, as shown in the chart below.

In fact, the derating specification for any power supply should be considered carefully, as it is not always clear in datasheets and can be misleading. Some manufacturers like to focus attention on their product headline ratings, quoted for, say, 20°C operation, while giving low prominence to a derating curve that may start to fall away sharply at temperatures as low as 45°C. This means that at the elevated temperatures encountered within a light box, the supply’s power output may drop to an unacceptably low level.

Fig.1: Driver load/temperature derating curve

Specifying LED strips suitable for lightbox applicationsApart from their high CRI and other performance characteristics as described above, LED strips are available with features that enhance their reliability in light box environments.- Have you considered increasing your LED DC operating voltage? Operating at 24 VDC rather than 12 VDC has reliability and cooling benefits. Doubling the voltage halves the current required for a given power demand. This reduces heat generated within the PCB, which increases the LEDs’ lifespan; it also allows a slightly longer run of LED tape.

- How well constructed is your LED lighting strip? Lower cost products will have lower quality or less copper on their PCBs, leading to I2R heat losses and possibly premature failure of the LEDs. PowerLed designs avoid this problem by adding extra copper layers.

Overall, lightbox designers seek value from versatility. Ideally, they want to produce striking and original bespoke designs that are differentiated from one another and the competition, yet employ common lighting components for economy of development and test. PowerLed can help identify a set of core LED and driver products that can be used across a wide range of project designs and implementations.

AMBIENT TEMPERATURE (°C)

LOAD

(%)

-10 0 10 20 30 45 50 60

20

40

60

80

100

12V,24V

48V

(VERTICAL)

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Meeting safety standardsThe LED strips and drivers must have CE marking to comply with EU health, safety and environmental standards. Knowledge of the requirements not only allows OEMs to build products that are legally compliant, but also assures the safety of their users, the reliability of their products, and protection from warranty claims or litigation issues.

CE marking comprises several key components including:

- Safety

- RoHS

- Electromagnetic compatibility (EMC)

- Ecodesign

The chart below shows these components’ hierarchy in more detail.

Fig.2: Lighting safety standards hierarchy

Safety: The Low Voltage Directive is concerned with ensuring a high level of protection for public interests, and guaranteeing fair competition in the EU market. It applies to equipment with voltage limits between 50 and 1000 VAC or between 75 and 1500 VDC at its input or output terminals. The limits do not cover voltages within equipment, and do not apply to components.

The current Directive is based on 2014/35/EU, and to meet it, LED drivers should fulfil both EN61347-1:2008+A1:2011+A2:2013 as a general requirement, and EN61347-2-13:2006 for LED control gear safety approval.

RoHS: The use of certain hazardous substances in electrical and electronic equipment is restricted under the current Restriction of Hazardous Substances (RoHS) Directive 2011/65/EU, which has been in force since 2 January 2013. LED drivers must comply with this Directive.

LVD

EMCCE

Ecodesign

RoHS Power Factor

Standby Power

Starting Time

Electro-magneticsusceptibility (EMS)

Electro-MagneticInterference (EMI)

Conducted/radiated emission EN55015

Harmonic Current EN61000-3-2

ESD Air/Contact EN61000-4-2

Surge susceptibilityEN61000-4-5

Voltage Flicker EN61000-3-3

RF Field susceptibilityEN61000-4-3

Conducted susceptibilityEN61000-4-6

EMS for generallighting purposes

EN61547

Elect fast transient & burst immunity

EN61000-4-4

Mag Field immunityEN61000-4-8

Volt dip, interruptionEN61000-4-11

EN61347-2-13

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The Electromagnetic Compatibility (EMC) Directive: The main objective of EMC Directive 2014/30/EU is to guarantee the free movement of apparatus and to create a harmonised and acceptable electromagnetic environment in the community. Its main goals are:

- To ensure that the electromagnetic disturbances produced by equipment does not affect the correct functioning of other apparatus as well as radio and telecommunications networks, related equipment and electricity distribution networks.

- To ensure that equipment has an adequate level of intrinsic immunity to electromagnetic disturbances to enable them to operate as intended.

The Directive explicitly specifies the function and responsibility of each party who places electrical equipment onto the market.

Ecodesign considerations and the 2009/125/EC Directive: Ecodesign regulations are intended to promote environmentally friendly design, reducing the environmental impact of Energy Related Products (ErP) throughout their entire product lifespan.

The regulations require manufacturers to decrease the energy consumption of their products by establishing minimum energy efficiency standards. By setting these standards at European level, manufacturers do not have to navigate through multiple national regulations when launching their products on the market.

For LED drivers and control gear, three ecodesign issues are particularly important: Starting time, standby power consumption and power factor. For example, an LED driver with output power up to 250W must consume standby power of no more than 0.5W.

For more information on LED drivers and safety standards, see the PowerLed article ‘Choosing LED drivers to ensure your LED luminaires’ CE compliance’.

Since non-compliant driver and LED products create technical, commercial and legal issues, it’s essential to be sure of the certification’s suitability and provenance. PowerLed performs full testing; some of it is in-house, while other aspects are handled by the Lighting Industry Association (LIA) Laboratory, which is Europe’s largest independent test laboratory dedicated to lighting. The Laboratory can help with proving performance as well as safety standards, and provides highly-credible independent verification of PowerLed’s products’ capabilities.

Ensuring safe and reliable lighting component designIf a lighting component is CE certified as described above – and the certification has been issued by a reputable body – then it will perform safely and reliably provided it is installed and operated correctly. But what can manufacturers do to deliver this performance to the highest possible level, and under varying environmental conditions?

PowerLed products have many design features, some as standard and some on semi-custom or custom products, that address this issue. Both drivers and LED strips can be encapsulated or ’potted’ in a high-grade polyurethane or high grade silicon compound to achieve an IP rating. Using a high-quality potting product is essential, as lower cost resins can degrade quickly in natural UV light, becoming yellow and discoloured. This will be unsightly, adversely affect the LEDs’ lumen output, and may crack with expansion and contraction.

LED drivers are available in aluminium chassis for better ruggedisation and heat dissipation, and some have fire ratings allowing mounting on potentially flammable materials like MDF. They are also easier to install as, unlike some products, they do not have orientation issues. Problems with fans becoming blocked or failing are also avoided as the drivers are convection cooled.

Some drivers provide overload shut down capabilities, possibly with ‘latch-off’ as mentioned previously, to avoid unwanted power cycling. ‘Power OK’ indicator LEDs on the drivers’ monitoring the driver allows DC power availability to be checked at a glance.

Ensuring protection and safety of the complete sign or light box: Signs or display units must be rated to an ingress protection (IP) standard, as defined in EN60529, to stop the ingress of water or foreign bodies. Otherwise they are liable to fail, or become dangerous to personnel maintaining them. The appropriate level of IP rating depends on the severity of the environment; the charts opposite show how the levels of protection are specified.

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Fig.2: IP (ingress protection) rating charts

Submersion depth and time must be specified by the manufacturer. The requirement must be more onerous than IP67.

Degrees of Protection - First DigitThe first digit of the IP code indicates the degree that persons are protected against contact with moving parts (other than smooth rotating shafts, etc.) and the degree that equipment is protected against solid foreign bodies intruding into an enclosure.

Degrees of Protection - Second DigitThe second digit indicates the degree of protection of the equipment inside the enclosure against harmful entry of various forms of moisture (e.g: dripping, spraying, submersion, etc.)

First Number Test

0 No special protection

1 Protection from a large part of the body such as a hand (but no protection from deliberate access); from solid objects greater than 50mm in diameter.

2 Protection against fingers or other objects no greater than 80mm in length and 12mm in diameter.

3 Protection from entry by tools, wires, etc., with a diameter or thickness greater than 1.0mm.

4 Protection from entry by solid objects with a diameter or thickness greater than 1.0mm.

5 Protection from the amount of dust that would interfere with the operation of the equipment.

6 Dust tight.

Second Number Test

0 No special protection

1 Protected against vertically falling drops of water or condensation.

2 Protected against falling drops of water, if the case is disposed up to 15 degrees from vertical.

3 Protected against sprays of water from any direction, up to 60 degrees from the vertical.

4 Protected against splash water from any direction - limited ingres permitted.

5 Protected against low pressure water jets from any direction. Limited ingress permitted.

6 Protected against high pressure water jets from any direction. Limited ingress permitted.

7 Protected against short periods of immersion in water - between 15cm and 1M.

8 Protected against long, durable periods of immersion in water, under pressure.

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PowerLed drivers are available with various IP ratings, and IP68-rated connectors are available to allow reliable cable assemblies in wet conditions.

Signs must be securely mounted: All signs should comply with BS559 in terms of their design, components, construction and installation. This not only ensures legal compliance, but also protects their users and the public from risk of injury; there have been instances of passers-by injured or even killed by falling signs and display units. Additionally, compliance reduces the risk to manufacturers, installers and operators of litigation and loss of reputation arising from any incident.

Protection from fire hazard: raised temperatures increase fire risk, especially if products such as perfumes are on show – a flammable vapour evaporates from these. This highlights the danger that power supplies and drivers can run on a moderate overload at a level just below their fold back point. In this mode, they can start to ‘cook’. This situation has led to more than one store fire in the past where a sub standard product has been used.

Accordingly, it’s important that drivers have ‘T/C’ points for technicians to check temperatures, and identify and rectify these fault conditions.

Energy efficiency: Power consumption by the drivers and LEDs must be minimised, and not just for safety and CE compliance. A large array of FSDUs, endcaps and POS CDUs will generate a significant power requirement and load on a store’s power supply, which must be allowed for and managed accordingly. Additionally, users consistently seek to cut their energy costs and improve their green credentials.

PowerLed offers drivers that operate with high efficiency over a wide load range. They also feature PFC, which reduces sizing requirements for mains supply cables and switchgear. These are further minimised as the drivers incorporate low inrush current circuitry. Additionally, the products meet ErP Level 6 standby power requirements for external power supplies.

Highly efficient drivers and LEDs reduce costs in many ways; not only through direct energy savings, but also because cooler running means longer operational life with reduced maintenance and component replacement bills.

LED Flexible Strip example.

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Ongoing product availability:

We have outlined some of the dangers in dealing with low-cost lighting component suppliers; these include issues related to reliability, safety and inadequate certification.

However, buyers should also consider the possibility that the supplier could go out of business. This is not unusual, and occurs across the spectrum from small companies and start-ups to large organisations. Statistically, an LED driver is less likely to fail than the company that provided it.

If it does happen the light box manufacturer must spend time and money on sourcing a new part, then testing and re-certifying the modified light box. Any remote IoT-type (internet of things) control and reporting capability may also be compromised through lack of support or availability. Meanwhile, opportunities for sales and building market share are being lost.

The customer perspectiveWe have reviewed feedback from a selection of customers who regularly consume PowerLed products, which can be summarised best as below:

“To understand how we value PowerLed’s products and services, simply consider what we’re consistently endeavouring to achieve ourselves; light boxes with an unblemished performance that eloquently boosts our customers’ brand – and continues to do so for months or years without failure or interruption.

Overall, we draw solid confidence from our partnership with PowerLed. Their long-standing market presence invokes trust both in their knowledge and their ongoing stability. The choice of lighting and power components allows us to create the effects we want, time after time. And reliability is assured by their track record, the proven authenticity of their certifications, and the steps they take to design in resilience where it matters.”

ConclusionLED light boxes offer a cost-effective option for boosting brand awareness, but their performance depends on the quality of their internal power and lighting components.

Identifying stable, knowledgeable suppliers who can be depended upon to deliver the best available products and advice protects the buyer’s business at two levels. Eliminating exposure to negative aspects such as poor-quality construction or failure to comply with relevant legislation avoids problems such as on site failures, excessive maintenance costs, risks to personnel and customers, litigation and damage to company reputation.

On the positive side, well-chosen components of high quality will ensure attractive displays with tightly controlled colour effects that remain consistent both within an installation, and throughout a series of installations. This, coupled with a proven record of reliability and safety, will improve business opportunities and growth for both the builders and the users of light boxes and displays used for promotion.

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Icon Information ICON DESCRIPTION

TVU-GS safety approved

TUV safety approved

TVU EMC safety approved

Nemko N-mark approved

Nemko EMC approved

ENEC (European Norms Electrical Certification)

China compulsary certification

UL safety approved

USA EMC approved

European declaration of conformity

Scheme of IECEE for Mutual Recognition of Test Certificates for Electrical Equipment

EMC and radio communications compliance labelling

Protection Class II

Short-circuit-proof Safety Isolating controlgear

Built-in electronic controlgear with double or reinforced insulation

The lamp controlgear case temperature at any place shall not exceed 110°C

Independent lamp controlgear

Suitable for installing near furniture which is made from materials with unknown flammable properties

Safety extra low voltage

Maximum output voltage

Intertek Laboratories ETL Listed Mark for United States and Canada

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PowerLed Related Products

LBV Series Drivers60W / 100W 12/24Vdc

IP20 drivers

Small low profile chassis

Terminal connection

Wide ambient temperature

High Power Factor

0-10V Dimming

Low Ripple and Noise

UTR Series Drivers

30W / 60W 12/24Vdc

IP20 drivers

Small low profile chassis

Terminal connection

Wide ambient temperature

High Power Factor

0-10V Dimming

Low Ripple and Noise

High Efficiency Lightbox Driver60W / 100W / 150W 12Vdc / 24Vdc

IP20 Drivers

Low profile chassis

Terminal connections

High CRI LED Flexible Strip24Vdc Constant Voltage

CRI >90/95

2500K / 3000K / 4000K / 6000K tone

30, 36, 60, 120, 180 LEDs per Metre

Tight binning control

Rigid LED24Vdc constant voltage

Rigid fibre board

2835 High Power LED

42 LEDs per 500mm length

Tight binning control

3000K / 6000K

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AUDIO APPLICATIONSSIGN & DISPLAY APPLICATIONS

www.powerled.uk.comemail enquiries@powerled.uk.com+44 (0) 118 9408744

PowerLed Orion House, Calleva Park, Aldermaston, Berkshire, RG7 8SN, UK