What are UGR LED Panels?

What does UGR stand for?

One way to describe glare is by its acronym, UGR. A mathematical description of a luminaire's glare potential.
 

Glare, what is it?

When two light sources are directly in front of a person's eyes, a phenomenon known as glare occurs. For the most part, everyone has been there: trying to see the road ahead in the dark because of an approaching vehicle's headlights. Similarly, when poorly planned lighting in a workplace bounces off of computer screens, making it difficult to see what's shown, this may also happen.

The introduction of high-efficiency edge-lit LED panels has often led to increased illuminance levels, even in cases where computer displays do not reflect light. This is because the light is directed to the luminaire's diffusing surface rather from being concentrated in a reflector or louvre system. Standard LED panels produce glare due to their very bright surface relative to the backdrop, which is caused by their 100% direct illuminance.

How can one quantify glare?

An equation is used to compute the UGR rating:

8 times the logarithm of [0.25/Lb Ʃ(L2Ω/p2)] is the UGR.

The luminaire's luminance value is denoted by L. Luminance at the backdrop, denoted as Lb,

As observed by the observer, Ω represents the solid angle of the light source.

The Guth Index is denoted by p. The Visual Comfort probability takes this glare possibility into account.

The inclusion of ALL fittings inside a space is indicated by the Sigma sign (ǩ) in the calculation.

All of this points to the fact that a physical place is necessary for an appropriate UGR computation. A test laboratory is not the place to measure it.
 

How was glare managed prior to LEDs?

Light fitting reflections on the bright, extremely reflective displays of early desktop computers were a major issue. There were two distinct approaches to handling this:

Manufacturers of monitors began making displays that did not reflect light. There was an introduction of CAT2 fluorescent light fixtures. Their 65° cut-off angle made them less glare.

There are drawbacks to both approaches:

The contrast and colour brilliance of matte displays are diminished. Decreased sharpness, which may be mild to considerable depending on the thickness and layering of the matte surface and the monitor's pixel pitch Typically, dirt penetrates more easily, making cleaning a more daunting task. Grainy or hazy texture may be seen in some cases, especially when white or other bright colours are shown.
 

On LED screens, how is the glare managed?

Behind the diffuser of a high-quality LED panel are three primary components:
1.The light is directed towards the diffuser via a "Light Guide Plate."
2. A sheet that reflects light from inside the panel and sends it back to the Light Guide Plate
Because of their typical design, LED panels provide a broad beam angle of 120 degrees, which, in some installations, might cause UGR levels to exceed those recommended in BSEN 12464: 2002. A specialised diffuser, similar to the louvres on a CAT2 luminaire, may reduce the LED panel's beam angle and so solve this problem. Because the light is focused more precisely, further energy savings are sometimes possible, which is an extra perk.
 

Key Information Regarding UGR19 LED Panels

These LED panels, which are also called UGR<19, are made to help get a UGR19 rating in an installation, but they don't guarantee it, since the UGR rating that is achieved depends on the exact installation.

UGR ratings in actual installations

Recommended UGR ratings are shown below: