#Product Trends
What is the difference between back lit and edge lit led panel light?
Which one is really economical ?
General
In edge-lit models the LED chips are arranged on the inner edge of the luminaire. The light is then bounced downwards through a diffuser. Edge-lit was the most popular format in the LED panel category during the introductory stage of the LED lighting market. However, there has been a parting of the ways between models in terms of efficiency.
Backlighting has proved the natural benefit of projecting light through less material. Edge-lit retains a share of the market where unit costs are a higher priority than running costs, and where there is an aesthetic preference. However, the real saving is in the lower operational costs delivered by backlit panels.
Edge lit panels average lumen per watt is between 80-90lm while Black Light back lit panels average lumen per watt is between 120-130lm. Which means %50 more energy efficacy.
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Issues with edge-lighting
The first LED panels used edge-lighting. LED strips arranged around the inner face of the mounting frame of the fixture project light into the diffuser panel, which is then refracted downwards into the space. It’s an inefficient way to get light out of a fixture, but it’s a very cost-effective fixture to manufacture and transport. Further, having the LEDs within the depth of the frame means a very slim fixture, certainly slim enough to fit within the depth of plasterboard in a ceiling. And that can be a very attractive option for installers.
But it’s the technology within an edge-lit LED panel that has allowed prices to tumble. The unscrupulous panel manufacturer simply buys reels of cheap LED strip, mounts the strip into the frame and fits the diffuser. It’s this process that has made the LED panel market torturously competitive. Despite some fixtures coming without guarantees of build quality or performance, buyers are still very keen to purchase. The regret comes later.
Benefits of backlighting
Backlit LED panels are always more efficient than their edge-lit counterparts. Whereas the light created by the LED chips in an edge-lit fixture has to travel through the entire volume of the diffusing panel, the light from the matrix of LED chips in a backlit panel only travels through the thickness of the diffuser material – a matter of a few millimetres. Light losses within the fixture are lower, meaning a higher delivered lumen output.
Inside the Black Light backlit panel
Life Time
Edge Lit: Due to slim design, short distance between the leds will cause heating. Heating is the enemy of the led moduls and it will shorten the life time of the product. It might start flickering and turn in to yellow in a very limited time.
Edge Lit panels become yellow in a short time.
Back Lit: There is a reasonable distance between led moduls and also bigger room inside the luminaire which is enought for cooling. Operating in lower temperature will increase the life time of the product.
Edge lit panels average lifetime is 20.000 hours while the back lit panels average lifetime is 50.000 hours. Most of the edge lit diffusers becomes yellow in 6 to 12 month.
Brightness and Contrast
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Edge Lit panels cant be used in high ceilings. Due to their design they cannot provide enought light for the room.
Black Light Back lit panels are the correct solution for high ceiling types. Direct Light can be reach more distance.
Which one is really economical ?
Edge Lit panels are cheaper when you compare each panel price. Back Lit panels are cheaper when you compare the project cost. Also double or triple the edge lit panels product life.
For example a room of 70m2; 25 pcs edge-lit panels needs to be installed while there are only 10 pcs Black Light back lit panels can provide the same amount of light.
