There are several ways to make white light using led technology.

One of the first ways this was achieved was by using a Red, Green and Blue led and mixing the colours to create a pseudo white light. This is similar to the way in which televisions make white.

The most common method of making white light using led is to use a blue led and shift the colour spectrum by adding a yellow phosphor. This produces a white coloured light and by changing the tint of yellow phosphor used the colour temperature can be shifted.

You will hear a lot of manufacturers quote what may seem to be amazing or outragious lifespans for their products. In general if an led is powered correctly and the thermal management of the light fixture is handled correctly and led is capable of outlasting most traditional light sources such as incandescant and halogen.

What you may not know and what most manufacturers dont tell you, is how important correct thermal management is. What most manufacturers also don't seem to pay attention to, is the thermal degredation of leds ie how temperature relates to the lifespan of an led.

Currently all led manufacturers (not the fixture manufacturer but the led itself) provide specification sheets for their led emitters which show the relationship of heat to the lifespan of the led. When dealing with high power led ie leds of 1watt or greater, this chart for all manufacturers shows, that the 50,000hr lifespan is only achieved, if the temperature of the led (not the fixture) is kept below 30deg C. If the led exceeds 65deg C the lifespan of the led is drematically decreased, nearly halved and if it exceeds 125deg C this is usually where most led will breakdown or fail as the bonding method used to hold the silicon chip to the substrate fails.

Led temperature vs Fixture temperature. Very simply put, if you measure the temperature of the fixture you can be assured that the led will be running at a temperature around 10% higher than that of the fixture. This is simple physics as for the led to keep the fixture at say 50deg C it needs to generate more heat than this, due to thermal lag and losses in the material used in the fixture.

As an example our R4-MR16 retrofit globes and V2 Hybrid globes run at around 59-70deg C (at ambient 35deg C). This is why we state the estimated lifespan of this product at 30,000+Hrs unlike most manufacturers who still claim lifespans of 50,000Hrs by simply ignoring the specifications of the led manufacturers they use

So when looking at an led product, ask what temperature the product runs at when the ambient temperature is around 25-30deg C. If the fixture runs higher than 60deg C then it is highly unlikely this fixture will last more than 40,000Hrs and definately not 50,000Hrs.

If you want to see these charts for common manufacturers you can visit the website for manufacturers of led such as Citizen, Cree, Edison-Opto, Nichia, Luxeon, Bridgelux etc. You will also find other useful information like the true lumen output of the leds they manufacture.

Note** for low power led products such as those used in linear flexible led ribbon etc the lifespan is usually far higher as they operate at very low temperatures and don't suffer as much from things such as thermal runaway.

Lumens, Lux what is this all about? A great deal of resellers and some manufacturers quote Lumens and Lux. These are two different measures but are linked.

Lumens is the Luminous Flux or amount of light being emitted from the light source at the point it is emitted. Basically the amount of light right at the point where it is made.

Lux is a measure of Lumens per square meter as projected onto a surface. So this is the intensity of light on a surface at a specified distance from the light source. The most common measurement for lux is at 1m from the light source and this is usually the figure quoted. eg our X3 series has a minimum 908lux at 1m. Lux also halves for every meter away from the light source so at 2m our X3 has approximately 454lux.

Lux is an important measure especially in commercial environments where most countries have standards that relate to the amount of lux required at say a desk in your office or on the ground in a warehouse.

It is commonly accepted that blue leds where first created in 1971 by Jacques Pankove although with very low and inpractical light outputs. It wasn't until the early 1990s when Shuji Nakamura creted the first practical examples of blue led and around 1993 these went into production. It is as a result of this that today we have yellow shifted blue leds or white led. There are many companies that manufacture leds but only a few that manufacture the silicon. No one led is necessarily better than the other as you will find in most cases they all use silicon chips (the heart of the led) from the same manufacturer. You will find however that some of the silicon manufacturers also make led and in these cases, it can be assumed that their product may have the benefits of better product knowledge and application of the silicon chip used in the led.

EnviroLumiere uses silicon and phosphors from leading US, Japanese and Taiwanese based manufacturers in its custom leds and specifies leading brands such as Cree, Nichia, Lustrous and Edison-Opto for some of its outsourced products. All product has a standard 12month warranty however we do look at product failure on a case by case basis and if it is determined that failure is due to a poor quality led in the fixture, we will work at either repairing or replacing the fixture to the benefit of the custom upto 7years after the original purchase date.