LED Lighting Devices: Component & Concept

# Heat-sink: Parts of thermal system on LED which have function to transfer heat away (by conduction or convection) from sensitive components, such as dies & electronics.

# Die (or Chip): Small-block of semiconductor materials which emitting the light, as main part in fabrication of LED circuit.

# Packages >> (A) & (B):
Single/discrete components which encapsulating one or more LED die(s); possibly be equipped by optical elements and have thermal, mechanical & electrical interfaces.

Power source & bases (as standardized per IEC 62560) are not incorporated into this device, because it cannot be connected directly to the branch of circuit.

# Arrays or Modules >> (C) & (D):
LED light source without having caps, incorporating one or more LED package(s) on PCB (printed circuit board), and possibly including one or more of the following components, interfaces & control-gears: electrical, optical, mechanical & thermal. Power sources (based on ANSI standard) are not incorporated into this device.

LED modules are generally designed as replaceable built-in parts into luminaires, boxes, or enclosures; and not intended to be mounted at the outside of them (without special precautions).

# Circuit On Board (COB) >> (E):
LED arrays which is constructed (assembled) with dies on PCB.

# Control Gear >> (F):
Electronic components which is designed to control a power source by adjusting output voltage, current or duty cycle; to switch the amount & characteristics of electrical energy, which is delivered to the LED packages (components) or arrays (modules).

LED control circuitry does not include a power source!

# Light Engine >> (G):
Integrated assembly which is comprised of LED packages, arrays, drivers, and other optical, thermal, mechanical & electrical components. This device is intended to connect directly to the branch circuit, through custom connector that is compatible to the luminaires (for which it was designed and does not use the ANSI standard base).

# Drivers >> (H):
The devices that comprised to a power source & control circuitry, which is designed to operate LED packages, arrays, or lamps.

# Self-ballasted (integrated) lamps >> (I) & (J):
LED lamps that incorporating control gear & additional elements (which is necessary for stable operation of the light source), and designed for direct connection to the supply voltage.

# Retrofit lamps: LED lamps that intended as replacement for non-LED lamps, without requiring internal modification for the luminaires.

# Non-integrated lamps >> (K):
Assembling devices that comprised of LED arrays, packages & ANSI standard bases. This is intended to connect with the driver of luminaires (through ANSI standard lamp-holder/socket), but cannot be connected directly to the branch circuit.

This may include LED replacement for low-voltage halogen lamps.

# Semi-integrated lamps >> (L):
LED lamps which carry the control unit (gear), but operated by separated power supply.

# Luminaires >> (M) & (N):
Complete lighting unit that consisting of LED-based elements (packages, arrays, engines, or lamps – including panels) & matched-driver; together with the other parts for distributing light, positioning & protection, and connecting directly to the branch circuit.

Some luminaires may be non-repairable (factory-sealed), which cannot be dismantled without being permanently damaged.

Source:

Equipment Energy Efficiency (E3) Program,
Department of Industry & Science,
Commonwealth of Australia
© 2015
“Product Profile: Light Emitting Diodes (LEDs)”
LED Lighting in Australia & New Zealand

LED Decision ­‐ Making in a Nutshell

# LED lighting contains no UV & little IR.
They are warm to the touch, in spite of some industries claim that they produce no heat. So consider carefully, how they might be used inside enclosures.

# To save most energy, insist on high luminous efficacy; 40 lumen/watt is a good starting point. Lower than that, cost savings will be marginal.

# To illuminate areas with more utilities (such as machinery, science exhibits, food services, hallways, educational activities, etc.); settle a color rendering index (CRI) above 80. For more attentive activities (such as viewing arts, ethnography, natural history collections exhibits, etc.); select LEDs with CRI above 90.

However, because CRI is an imperfect metric, it should be considered a target, not a firm criteria.

# If you wish to replace any conventional lamps (such as tungsten, halogen, or equivalent incandescent lighting) and still prefer to get “warmer“, select a color temperature between 2700K to 3500K. For preferences “whiter” or little “cooler“; pick 4000K ore more.

But generally, avoid higher color temperatures for light-sensitive materials, which common-used LEDs may have unacceptable peak at “blue” region in their spectrum.

# Be cautious of color temperature & CRI claims, because lamp-to-lamp consistency may not be adequate. Agree with vendor on your right to replace the lamps supplied, when consistency is inadequate out-of-the-box or a lamp changes color during operation.

# If possible, acquire & review LM-79 reports or any colorimetric-test results from the lamps’ manufacturer; looking for a positive (+)Duv specification which greater than +0.006 (exactly +0.0054). If the lamps may introduce a greenish appearance, perhaps it should be avoided.

# Once you have made a preliminary decision on several candidate-lamps, look at all of them by yourself:

o Checking color rendering on your own skin;
o Try for dimming it with recommended dimmers & specified transformers;
o Checking for flicker in undimmed & dimmed state;
o For LED-strips lighting, it should be dimmable to provide high level control in compact space. Dimming may extend the lamps’ lifetime, but the flicker could be a problem. Check this carefully!

# Most large brand-named lighting companies supply high-quality products, but they also supply poor ones. Make no assumptions of quality based on brand alone, because sometimes the smaller companies are motivated to provide a good support.

# Do not compromise too easily, if a given manufacturer does not have the right lamps based on your specifications or requirements (such as lumen, color, beam angle, or type of the lamps). There are many good products in marketplace that can cover a range of utilities and another manufacturer’s products may fit to your needs better.

# Retrofit lamps are easy to install in existing tracks or fixtures; but do not discount the lamps with a dedicated or unique design & shape. Some of these only require an adapter to fit an older track from their manufacturer.

# If you are going to be dimming your LEDs, confirm that the method is compatible to the used chips & drivers. No LED will change color upon dimming, when used the technique of pulse-width-modulation (PWM); but some of PWM techniques can introduce the flicker.

White phosphor LEDs may change color if the dimming is accomplished in same manner with as incandescent lighting – reducing the line voltage.

# Knowing what your product warranty covers!
A one-year warranty is common, but for longer periods of time coverage may be limited to a catastrophic-failure of the LED-chips. Failure of ballasts & drivers may not be covered at all.
Consider the return on investment payback (ROI) period!
You may be satisfied if ROI payback is less than the warranty period. Warranties exist that cover the major failures, significant loss of luminousity, and any visible change in color-temperature for up to 25,000 hours.

Source:

Druzik, James R., & Michalski, Stefan W. (2011), “Guidelines for Selecting Solid-­‐State Lighting for Museums”, Canadian Conservation Institute & The Getty Conservation Institute (with some edited).