LEDs are an energy efficient and long lasting source of light. However, they create hot spots of focused light, which are very intense and bright. Hence, diffusers need to be used for an even distribution of light. This article focuses on the various materials used in light diffusers and on how to choose between them.

By Baishakhi Dutta

The light from LEDs can be harsh to the human eye because of the bright concentrated LED hot spots, which could be jarring when lighting larger spaces. To create effective luminaires using LEDs, lighting manufacturers use multiple LED point sources. But creating a soft glow or reducing glare is important, for which diffusing or light blending technology is used.
Light diffusion is a technique whereby the brightest light near the edges of the bulb is transmitted to the areas of the light box that have the least amount of light. Through this method, an even distribution of light takes place. To achieve this, a diffuser is used. A perfect diffuser is one that creates Lambertian scattering so that the radiance is independent of the angle. With applications ranging from projector screens to commercial lighting, it becomes tough to decide upon which type of diffuser is best suited for you.
For aesthetic and effective optics design, glass and transparent plastics (especially acrylic resins) have been long standing favourites. With the shift towards LEDs, lens and cover producers have focused on developing suitable plastic solutions.

Types of light diffuser solutions
The traditional method of diffusing light is to position a frosted glass in front of the light source. But glass has a very high absorption-coefficient, which blocks a large amount of the LED light output. Apart from that, glass is heavy, increasing the weight of the whole product. It also does not possess the required toughness and is prone to breakage.
Nowadays, manufacturers are adopting new ways to develop cost-effective diffusers entirely from plastic. The types of diffuser solutions that dominate the market these days are:

• Diffusers for panel light tube covers
• PMMA optical diffusers
• Three-sided diffusers
• Transparent diffusers
• Satin diffusers
• Anti-glare diffusers
• Opaque diffusers
• UV stabilised diffusers