With the rise of the lighting industry and the improvement of people’s living standards, lamps are widely used, but at the same time, many problems begin to appear, such as heat dissipation, waterproofing, protection, illuminance, beam angle, brightness, UGR and so on. Today we’re talking about UGR.

What is UGR? I believe this is no stranger to senior people in the industry. Disability glare is a glare that reduces visual efficacy and visibility, and it is often accompanied by discomfort. It is mainly due to the stray light of the high brightness light source in the field of vision entering the eye and scattering in the eyeball. Disability glare is measured by the ratio of the visibility of a job under a given lighting facility to its visibility under reference lighting conditions, called the disability glare factor (DGF). Uncomfortable glare, also known as “psychological glare”, refers to glare that causes visual discomfort but does not cause reduced visibility.

The above two kinds of glare are the so-called UGR (Unified Glare Rating), that is, unified glare value, which is one of the main contents of lighting quality in lighting design. The same UGR is not only a visual problem, but also a problem in design and application. So how to reduce UGR to comfort as much as possible?

1. Product design first

General lighting fixtures are composed of housing, power supply, light source, lens or glass. At the beginning of design, there are many ways to control the UGR value, such as controlling the brightness of the light source. Or do an anti-glare design on the lens and glass.

2. Still design

Within the industry, it is agreed that there should be no UGR, if the following conditions are met for lighting fixtures:

(1) VCP (visual comfort probability) ≥ 70; (2) When viewed longitudinally or horizontally in the room, the ratio of the maximum luminance (the brightest 6.5cm²;) to the average luminance of the lamp at the angles of 45 °, 55 °, 65 °, 75 °and 85 °to the vertical line is ≤ 5∶1 (3) to avoid uncomfortable glare whether vertically or horizontally, the maximum brightness of the lighting fixtures and the vertical line at all angles should not exceed the provisions of the following table:

Vertical Angle(°) Maximum brightness(cd/ m²;)
45 7710
55 5500
65 3860
75‍‍‍ 2570
85 1695

3. Methods to control UGR.

(1) Avoid installing the lights in the interference area;

(2) Use surface decoration material with low glossiness;

(3) Reduce the brightness of light fittings.

There are many ways to control UGR, interested friends can find their own solution. Think what I said is not correct or not comprehensive, welcome to comment and leave a message to correct and supplement!