A technique that started in Korea stemming from the Ultra thin TVs is the edge Lit LED panel. These started out being produced with quality in mind, but a mass of new suppliers were able to purchase materials in China and form new cheap versions. We started producing LED panels in 2010 and have found a larger greater pressure to produce cheap since, but our panels are still not failing. First factor from our panels is the Formed aviation grade aluminium heat sink back, its like a folded tray..the folded edges wrapping around the backs of our UL approved 1.4mm thck PCBs.
Now why should a potential "sales point" of aviation grade aluminium make a difference over the 0.3mm sheet steel used on 99% of Cheap ones? Answer: thermal heat dissipation area/strength. By forming a 1.2mm thick aluminium sheet and making this a "housing" we have factually tested our PCBs to be running 35% lower heat on the leds when compared to sheet steel backed versions.
A visual comparison is easy, if the panel is rivetted shut at the back with a sheet steel back...then its cheap construction. What you find inside will potentially be worse. The "Led Driver brand" alone does not constitute a good LED panel.
Next is the infamous "Light Guide Plate LGP" this is a sheet of Acrylic that has been printed on the back to allow light to bounce forwards from the print. We still use original Mitsubishi Acrylic at 4mm and laser print with a ultra uniform printing. All of the cheaper ones cut this area down using 2.5/3mm Acrylic often produced in China that will discolour (Yellow) quickly around the edges and with the the thickness the forward reflected light will be worse. The screen printing technique changed also from the laser print we apply to a silk screen print used on cheap versions, the uniformity suffering drastically.
Next is the front diffuser, we use a 750degree glow wire tested cover that splits the light once again many low end versions will use a simple milky sheet that will not aid the smoothness of the panel. The Next is diode usage..we have tested every form to guage the best "forward" light output. It is fact using this type of panel you will suffer "light loss" from the reflective nature from the diode to the front Lm output but how much is governed by the construction. From 120Lm/W Leds 5630 we will get 25% light loss in refraction, however from other diode types coupled with materials this figure can be more like 45%.
To gain quality all the above factors effect the light eveness of the LED panel but then you have Light factors created by diode usage and the materials. SDCM is appertaining to the colour tolerence, our SDCM is very narrow at under 2.5SDCM where as many are up in the 7/8s. Also Cri is important and due to high quality diode usage we are able to produce high Cri panels couldpled with the excellent SDCM.
Many rumours circulate within industries about what constiutes a "good LED panel" the latest being to view whilst on with I-phone to measure the "ripple", in laymens terms if you see it strobing then its not good!. This is down to the driver alone coupled to the resistance in the circuit but again does not mean a great panel, it means a ultra high quality driver. Small ripples are not great issues and are formed by the Constant current nature of a panel, large ripples will consitute very poor harmonics.
LED Edge lit panels are "Fashionable" due to the thickness but actually interms of straight forward light output the back lit options are better. But following fashion should you have a project, site, job..be specifying..or choosing then choose carefully, very carefully because a lot of poorly made product exist in the worldwide markets.
We have witnessed products that are ultra high kelvin to offset the low quality materials used, low quality construction. Even using a led as a circuit resistor to regulate the current on the PCBs.
Fortunately as a manufacturer with clients in many nations we set a standard of quality we feel will mean 5yr Guarantee..by testing, by ensuring standards to that end we have most indpendant approvals. Clients globally have offers daily and can choose from a massive amount of suppliers/producers in China or regionally but I urge those who do buy/specify to ask more questions.
The most simple test is put a magnet on the back...if it sticks see how thick that sheet steel is...then check the light...the temperature...place your fingers on the aluminium frame..if its hot after 10mins...your leds will depreciate quickly...
Because generally in China you will be told one thing (price to entice) until you ask for the details, when you ask for the details suddenly the price will be much higher! So you cannot compare like for like in the China manufacturing market. We have a cost to manufacture and that comes purely down to the qtys required by the distributor so how can we offer out prices in general marketting? The best projects then are ones that have lighting schemes done upon qualified high quality products with no future calls in regards to failures.
Having started in the Lighting business in 1996 moving from distribution to manufacture we all came into this business to fulfill the above. Some distributors work purely on price...most lighting professionals will work to not get things wrong. With the LED market growing over the past 8yrs...I have watched from the manufacturing side and seen samples entering our test areas that are not made to please but made for price.
As a lighting professional and now LED professional we ALL need to stay away from products that will come back to haunt us and endevour to stick with the original principles of LED. Longevity, lifespan, efficiency...and ROI for the end user. Of course if everyone had the same it would make us boring!! But it is always worth knowing why some are more expensive than others.....
The finished scheme/project/office will know the difference for a slight change in costing....