LED PANEL LIGHT

LED panel lights offer a contemporary, sleek alternative for ceiling lighting to old-dated fluorescent lighting. An LED panel light is designed to provide sufficient lighting of varied light intensity, or lux level. Panel lights offer “edge to edge” lighting for smooth, even and bright output.

LEDs are oriented directly toward light diffusing layer, inducing the light emitted from LEDs to shine directly onto light diffusing layer.

Two of the primary lighting panel structures are direct-lit backlight modules and edge-lit modules The difference between edge-lit and back-lit lies in the position of LEDs and the usage of LGP(light guide plate). Normally, Back-lit Panel Light doesn’t have any LPG due to direct shining method.

A direct-lit LED panel comprises a number of LED light sources which are directly disposed under a panel. But LED is a form of directional light source, of which light output intensity is strongest at 90 degrees.

LEDs are oriented directly toward light diffusing layer, inducing the light emitted from LEDs to shine directly onto light diffusing layer. As a result it creates a point source of light which can be uncomfortable or harmful to a person's eyes. For a direct-lit light panel having the diffuser layer disposed too near the LED light sources, the light output is non-uniform and hot spots (i.e. the strongest light output intensity area) will be observed.

The introduction of the edge-lit LED panel lights is based on balancing the relationships of the aforementioned factors to achieve a fixture that produces a light output that appears consistent to the human eye across the diffuser panel.

Structure of Panel Light- Edge-lit LED Panel light.

The main structure of Panel light consists of six parts: LGP(Light guide plate), Diffusor Plate, Reflector film, LED light source, Frame and Back Plate, LED driver.

LED light source:

LEDs come in a variety of sizes and brands. The size 3014 and 2835 are very popular in the market for Led panel light production. LEDs in the same size from different brands show different optical parameters.  A high CRI and light efficiency LEDs obviously will improve the whole Panel light’s optical performance under the same light design. A back-lit Led Panel light usually take 2835 for the light source, but 3014 will be a good choice for an edge-lit panel light.

LED driver:

Led driver is important part of light fixture, which connects the light with AC power. 

   Normally Led Panel light has an external driver to supply power. It’s important to select a suitable driver so that the light works longer. Things to consider while choosing driver are:

Power and current: Choose the driver that has correct output power range and current

Power factor: A high power factor let your panel light more energy-saving

Protection and Safety compliance: Be sure the driver has enough protections such as open-circuit protection, short-circuit protection, overvoltage protection, over temperature protections, etc.

Other configurations: Dimmable or non-dimmable, constant current driver or constant voltage driver, etc.

Certification: Make sure the driver has passed a certain certification such as FCC, TUV, CE, etc.

Electronic circuit model: isolated circuit will be safer than non-isolated circuit as Panel light may have an aluminium frame and back plate.

Light Guide Plate (LGP):

LGP transfer the linear light to surface light. When light enters LGP from both sides of the light source and touches the reflection dot, it will be diffusely reflected onto the surface of LGP, the other part is that light penetrates directly LGP and reaches the surface. Therefore, the reflection dot’s distribution and design play an important role in LPG’s function. The material and design of LGP determine mostly the Panel light’s luminous efficiency and brightness.

There are different processing methods with different materials. Each material has a suitable processing method. The main processing technology of LPG includes silk-print, laser engraving, etching, and injection molding.

Process Technology

Corresponding Material

Suitable LEDs

Silk Print

PMMA

3014/4014

Laser engraving

PS

3014/4014/3020

Etching

pc

3014/4014/3020

Injection molding

pp

2835

Diffuser Plate:

The aim of diffusor is to export uniformly the light of LPG, and also to blur the reflection dots. A “diffuser” is any material that scatters light, but it's most commonly applied in the form of a light panel or cover. The main purpose of a diffuser is to diffuse (or “spread out”) light without sacrificing light transmission. It makes bright or harsh light softer across a wider area and eliminates some of the unwanted glare caused by recessed lights. Laser etching, chemical etching and shape painting are presently used as diffuse light extraction features.

Main material of diffusor plate: PC, PMMA, PS, PP.

Reflector Film:

The purpose of the reflector is to reflect the light exposure on the bottom to the light guide plate, to improve the efficiency of light. Its reflectivity affects the brightness of the display.

Reflective film requires a special particle structure to match the printing point of the light guide plate, not only to reflect light, but also to make the reflected light relatively uniform. With these special reflection films, by changing the design and the mold, the center brightness can be improved by nearly 30%.

Frame & Back Plate:

The frame is for the appearance and also for the heat dissipation. Panel light frame can be made of PC, plastic or stamping aluminium and die-cast aluminium Die-cast aluminium is mainly used to making the panel lights that have a seamless profile in small sizes.

The back plate is to seal the whole Panel light and help also the heat dissipation. Therefore, it’s very common to use metal material to produce a back plate is iron or aluminium composite plate.

Structure of Panel Light- Back-lit LED Panel light:

The back-lit Led Panel light has a simpler structure. LGP is not necessary for backlit Panel light.

The key difference between Edge-lit and Back-lit panel is where the LEDs are located and the way that light disperse from each fixture. 

In Edge-lit panel light has LEDs placed on the edge of frame. Light emits from either side and is dispersed through the Panel’s lens.

In LED backlit panels LEDs lined up on the back of the frame. The LEDs point downwards shining light directly through lens.

Edge-lit panel requires more LEDs to emit the same level of lumen, when compared to Backlit design, raising the cost per fixture.

Backlit panels require deeper housing, making them about twice the thick than Edge-lit.

Backlit panels are intended to be installed in drop ceilings.

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