LED Terminology

LM-80-08

LM-80-08

Dec 2016
LM-80-08 is the Illuminating Engineering Society of North America (IESNA) approved standard for measuring the lumen depreciation of solid-state lighting sources, such as LED packages, modules and arrays. LM-80-08 testing report will provide luminous flux for a given current over a 6,000 hours period with interval measurements. Luminous flux will be measured under 3 different … Continue reading LM-80-08

LED junction temperature is the highest operating temperature of the actual semiconductor in an LED device. In operation, it is higher than case temperature and the temperature of the part’s exterior. The difference is equal to the amount of heat transferred from the junction to case multiplied by the junction-to-case thermal resistance.

RC Driver

RC Driver

Dec 2016

RC (Resistance-Capacitance) driver is just a simple LED driver mode. It actually through RC buck rectifies a 220V AC power to a certain DC voltage. It is a rough and unstable, less demanding driver. RC driver is cheap but less efficient, it will lead to the LED decay quickly, even burned.

‘Isolated’ refers to a circuit separated from the AC line in order to prevent electric shock. Isolated power supply has a power output that is electrically independent of its power input. This type of power supply is safe but less efficient. 

A non-isolated circuit is one not shielded from the AC power source, which makes electrocution possible.  This type of design is mainly for double-insulated products, such as LED replacements for bulbs, in which the LED and the whole product are integrated and sealed in the non-conductive plastic, making the light fixture safe. Usually, the driver … Continue reading Non-isolated Driver

Constant voltage drivers require a fixed voltage (usually 12V DC or 24V DC), and current is usually regulated by either resistors that have been wired in series with the LEDs or by an onboard built-in regulator driver that the LED module may have. This type of LED is often used in signage where it is … Continue reading Constant Voltage Driver

With constant-current drivers power (Usually 350mA, 700mA and 1A) LEDs require a fixed output current while the voltage output will vary depending on the load. The more LEDs are attached, the higher the output voltage will be, up to a maximum set by the driver. This type of driver is usually used when the load/number … Continue reading Constant Current Driver

LED driver efficiency is the ratio of the power delivered from the driver divided by the power required to operate the driver. It describes how much of the power drawn by the power supply is lost in heat. A highly efficient driver dissipates less heat and allows for easier thermal management to stabilize the design … Continue reading LED Driver Efficiency

Power Factor

Power Factor

Oct 2016
Power factor describes how efficiently an LED driver uses electricity. It is the ratio of the real power that is used to do work and the apparent power that is supplied to the circuit. The power factor can get values in the range from 0 to 1. The closer to 1 the power factor is, … Continue reading Power Factor

Thermal Resistance is an indication of how effectively a unit rids itself of heat. Thermal resistance for an LED is used to determine the difference in temp between the package (heat slug) and the die.

Heat dissipation refers to the intentional transition of thermal energy from a hotter object (such as a sensitive electronic device) to a cooler object. Heat dissipation is achieved with LEDs primarily by mounting them on high thermal conductive materials such as copper, aluminum and other alloys, or by enhancing the cross-ventilation of the air around … Continue reading Heat Dissipation
Thermal management is the core issue throughout the entire process of LED light R&D, design, manufacturing and application. Unlike most other thermally-induced light sources (halogen, HID, MH, CFL, etc.), LED does not require extra heat to give light. In principle, LED emits photons directly when electrons and holes compound with each other, therefore, LED is … Continue reading Thermal Management
LED Lumen depreciation is a factor used to calculate the amount of the lumen output decrease over time. It is contingent upon the phosphor aging, decrease in the conversion efficiency of the diode itself, and the aging of the other components or materials. Use high quality encapsulation materials (including trust worth chip) and adopt good … Continue reading LED Lumen Depreciation
LED Array

LED Array

Sep 2016
LED array is a predetermined pattern of a number of LEDs mounted on a printed circuit board (PCB) or other surfaces, which is capable of producing light when powered.       LED array? COB? People often get confused by its inconsistent names. In white light illumination context, LED array and COB often refer to the … Continue reading LED Array
SMD

SMD

Sep 2016
SMD stands for Surface Mounted Devices. SMD LEDs use Surface-mount technology (SMT) to mount LED chips on printed circuit boards (PCB). These LEDs are recent, resilient, efficient and have high-reliability performance, they ideally suited to be used in general purpose LED lighting solutions.  Some common SMDs types are SMD 3528 (3528 refers to the size … Continue reading SMD
COB

COB

Sep 2016
COB refers to chip on board packaging solution. In this solution the chip or die is directly mounted on and electrically interconnected to its final circuit board. The COB solution includes die attach, wire bonding, encapsulation of the die and wires these 3 steps. The advantages of COB technology include saving systematic space, high packing … Continue reading COB
LED encapsulation is a process to implant LED chip into a sealed package body. The procedure is to pour liquid epoxy into the LED molding chamber first, and then insert the LED bracket that has undergone the press welding, then put the mold into the oven, and the LED gets shaped when the epoxy solidifies. … Continue reading LED Encapsulation
Luminaire efficiency refers to the ratio of the light emitted by the luminaire to the light emitted by the enclosed lamps.   The luminaire efficiency of the common light fixtures are as follows: Conventional Spotlights 40%-55% Conventional Floodlights 55%-70% Fluorescent 40%-55% LED fixtures 85%-90%
Transmittance

Transmittance

Sep 2016

Transmittance refers to the ratio of the intensity of incident light to the intensity of transmitted light. It is a  measurement of how much light passes through a substance. The higher the amount of light that passes through, the larger the transmittance. 

Failure analysis of LED luminaires is a process of collecting failed components of the luminaire for subsequent examination of the cause(s) of failure using a wide array of methods, often with the goal of being able to allocate the observed failure pattern to a possible root cause and then show a way to avoid it. 
LED Module

LED Module

Sep 2016
An LED module is a basic structure of LED matrix in applications. Usually, one LED module consist of square shape PCB(s). Classifying from the application environment, there are two types led modules. One is indoor LED module and another one is outdoor LED module. The latter module must be water-proof. LED module can also be … Continue reading LED Module

Solid-State Lighting refers to a type of lighting that uses semiconductor light-emitting diodes (LEDs), organic light-emitting diodes (OLED), or polymer light-emitting diodes (PLED) as sources of illumination rather than electrical filaments, plasma (used in arc lamps such as fluorescent lamps), or gas.

Lux

Lux

Sep 2016
A lux is the perpendicular incidence of a lumen on a surface of 1 square meter. Equivalent to 0.0929 lumens. When defining that a lux equals a lumen per square meter, it is specified that a lumen is equivalent to a candela x steradian. The total luminous flux of one candle source equals 4π lumens … Continue reading Lux
Lumens

Lumens

Sep 2016
Lumen is a measure of the luminous flux or quantity of light emitted by a source. The higher the lumen the brighter the light. For example, a dinner candle provides about 12 lumens. A 60-watt Soft White incandescent lamp provides about 840 lumens. In a less rigorous way the lumen can be interpreted as a measure … Continue reading Lumens
Integrating sphere is an optical component consisting of a hollow spherical cavity with its interior covered with a diffuse white reflective coating, with small holes for entrance and exit ports. The Figure below shows iLUXZ staff conducting integrating sphere test.
LED Drivers

LED Drivers

Sep 2016
LED drivers also known as LED power supplies. Similar to ballasts for fluorescent lamps or transformers for low voltage bulbs, they are electrical device that regulates the power to an LED or string(s) of LEDs. The difference is that an LED driver responds to the ever-changing needs of the LED, or circuit of LEDs, by … Continue reading LED Drivers
PCB (Printed Circuit Board) refers to a thin piece of fiberglass that has thin copper “wires” etched onto its surface. It has an electrical circuit imprinted in silver etching, says how the LED will operate, besides, it is the platform by which LEDs are employed in various applications. PCB also plays an important role in … Continue reading PCB (Printed Circuit Board)
LED Lens

LED Lens

Sep 2016
LED Lens is a  transparent or semi-transparent glass or synthetic element, which is used to effectively focus and direct the light of an LED. In terms of color, lens can be clear, white diffuse or diffuse. Diffuse lens are used in order to produce even illumination. Clear (or water clear) lens don’t affect the light output … Continue reading LED Lens
LED Heat Sink

LED Heat Sink

Sep 2016
LED Heat Sink is a thermal conductive metal device designed to absorbs and disperse excess heat away from LED diode, therefore allowing the regulation of the LED fixtures temperature at physically feasible levels. Heat sink is essential to the LED fixture, if it doesn't work efficiency, the LED phosphor will be damaged, resulting in lower … Continue reading LED Heat Sink
LED

LED

Sep 2016
A light-emitting diode (LED) is a special kind of diode that glows when electricity passes through it. Most LEDs are made from a semi-conducting material called gallium arsenide phosphide. The following Figure shows the LEDs of iLUXZ linear light. The light is not particularly bright, but in most LEDs it is monochromatic, occurring at a single wavelength. … Continue reading LED
Luminous efficiency refers to the ratio of the total luminous flux radiated by any source to the total radiant flux from that source commonly expressed in lumens per watt. The higher the lumen efficiency, the better ability the light sources have to convert electrical energy into light, which means that in the same brightness, lighting … Continue reading Luminous Efficiency
LED Luminaire reliability is the rate of random failure during the useful life phase, it describes the ability of the products to perform its intended functions under a specific set of conditions and for a specific period of time. It is usually defined in terms of mean time between failure (MTBF) which means the average … Continue reading LED Luminaire Reliability
IP Rating

IP Rating

Sep 2016
IP (Ingress Protection) Rating refers to the international standard that defines the level of protection that electrical appliances provide against the intrusion of solid objects or dust, accidental contact, and moisture. The rating is usually composed of two numbers, the first digit indicates the degree of protection against solid foreign bodies intruding into an enclosure, … Continue reading IP Rating
LED lights colors means the light emitted from a light-emitting diode has a specific wavelength and thus a specific color. "Visible light" corresponds to a wavelength range of 400 - 700 nanometers (nm) which correspond to visible colors from shortest to longest wavelength are: violet, blue, green, yellow, orange, and red. However, it is not difficult … Continue reading LED Light Colors
LED Lifetime

LED Lifetime

Sep 2016
The light output from all light sources, LED, halogen, metal halide and fluorescent decreases over time. For LED lights, the module does not die instantly the conventional light sources do, it slowly dims down. The lifetime of LED refer to the time it takes until its lights output or lumen maintenance reaches 70%, which is … Continue reading LED Lifetime
Flicker

Flicker

Sep 2016
Flicker refers to rapid, repeated changes over time in light intensity.  According to whether the flicker is consciously perceivable by a human eyes or not, there are visible and invisible flickers. Most of visible flickers are kind of defectiveness; however invisible flicker depends on different mechanism.  There're multiple reasons that can lead to flicker.     Reason … Continue reading Flicker
LED Phosphors

LED Phosphors

Aug 2016
Phosphors are substances which can absorb energy (including electromagnetic waves (visible light, X-rays, ultraviolet light)), and after energy conversion they will emit all different colors of visible light.  In the case of LED, a phosphor coating is deposited on the LED die, combined with a short wavelength LED such as blue or ultraviolet light to … Continue reading LED Phosphors
LED Diffuser

LED Diffuser

Aug 2016
LED diffuser is an optical element, such as a frosted or gridded lens used to soften the LED light. LED light is direct and intense, that will make human eyes feel uncomfortable. A diffuser will transform the point light source to uniform surface light source, making the light softer, brighter and without glare. Most diffusers … Continue reading LED Diffuser
LED Chip

LED Chip

Aug 2016
LED chip is the core component of the LED. It is a semiconductor chip, one side is attached to a stent, the end is negative, the other side is connected to the positive terminal of the power. It mainly functions to convert the electrical energy into light. The LED chip can be divided into low-power, … Continue reading LED Chip
Transformer

Transformer

Aug 2016
Transformer is an electrical or electromechanical device, made from two coils of wound wire that are connected so that one of the coils will send electricity to the other. It is one of the most common and critical components for LED driver.   The transformer can either increase or decrease the level of voltage running … Continue reading Transformer
Luminous intensity is the amount of light, luminous flux, radiating per solid angle in a specified direction. Intensity is measured in the SI base unit of the candela (cd) where 1 candela equals 1 lumen per steradian.
Luminous Flux

Luminous Flux

Aug 2016
Luminous flux is the quantity of the energy of the visible light emitted per second in all directions. The visible light refer to the light within the wavelength range of approximately 390 nanometer s (nm) to 770 nm. For the reason that human eye does not respond equally to all visible wavelengths, luminous flux is … Continue reading Luminous Flux
Illuminance

Illuminance

Aug 2016
Illuminance refers to the total luminous flux incident on a surface, per unit area. It is a measure of how much the incident light illuminates the surface. Illuminance also correlates with how humans perceive the brightness of an illuminated area when wavelength-weighted by the luminosity function.  The unit of illuminance is Lux. Many people usually … Continue reading Illuminance
Potting adhesive is a kind of electronic adhesive, used in LED packaging. Being high refractive index and high transmittance, it helps to protect the LED chip from possible external damage such as oxidation,physical scratching and pollution,and increase luminous flux by shaping the angle of light output. We choose the OE-6550 A/B optical encapsulants produced by DOW … Continue reading Potting Adhesive

The curves provide information about the way light is distributed from the fixture and also how that light falls upon a surface.

Gold bonding wire is used in one of LED packaging processes, the wire bonding process, to provide electrical interconnection between the LED chip and lead frame.
Nowadays, due to the high price of gold wire, some LED manufactures are using copper wire or even low performance alloy wire as alternative. However, compared to gold wire, copper is significantly more prone to corrosion issues, besides,

Glare

Glare

Jun 2016

Glare refers to the visual discomfort and visibility dropping which is due to the inappropriate brightness distribution, or to the extreme brightness contrast in space or time. The glare can be caused directly by the light source, or the light reflected from a surface.

A component of the LED driver, with function to offer high capacitance value on to the circuit board. Many people argue that the electrolytic capacitor is the bottleneck factor of LED lights.

A measure of the color of a light source relative to a black body at a particular temperature expressed in degrees Kelvin (K). It characterizes how the white light looks. For instance, if the light goes more blueish, it would have a “cool” temperature, and if it’s more reddish, it would be “warm” in temperature.

A measure of the quality of color light. To help determine how well lights reproduce color, bulbs are given a CRI score between zero and 100. This score represents a comparison between the spectrum of colors the light produces and the spectrum naturally produced by the sun in the same color temperature. For example,

Beam angle or beam spread is the term describes the angle between the two directions opposed to each other over the beam axis for which the luminous intensity is a certain fraction of that of the maximum luminous intensity. The amount of that fraction needs to be given in each specific case. When the fraction … Continue reading Beam Angle (Beam Spread)

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