Apr 10, 2020

Single LED Focal Length Simplifies Optics for Entertainment, Architectural, and Emergency Lighting

Category: Illumination
Achieving these exciting light effects for entertainment venues – or for high-impact lighting for architectural and emergency-vehicle applications – isn’t easy, unless you have the right technology.

Achieving these exciting light effects for entertainment venues – or for high-impact lighting for architectural and emergency-vehicle applications – isn’t easy, unless you have the right technology.

When attending a rock concert, the show’s lighting effects are sometimes as notable as the musical performances. Shifting beams of vibrant, ever-changing colored light and the blaze of precision spotlights add energy and excitement to musical concerts, particularly when the colors are rich and dynamic, and mix and blend organically to form their own spectacular dance.

However, achieving these exciting light effects for entertainment venues – or for high-impact LED lighting for architectural and emergency-vehicle applications – isn’t easy, unless you have the right technology.

The importance of focal length

Focal length is the distance between the LED emission surface and the secondary optics, which are the lenses and reflectors over the LEDs that create the desired appearance and beam pattern of the LED light. In a one-color LED array where all LEDs are mounted on one surface, the single focal length enables lighting manufacturers to craft a single secondary optic to produce their desired lighting effects.

However, in an array with multiple colors of LEDs, each color may have a different focal height. This might be due to differences in die height or the phosphor that is applied to achieve the desired color. Regardless of cause, it’s not uncommon for different colors of LEDs to have a different emission surface height and require optics unique to that color when it’s part of an array. The result is increased engineering effort, additional optics and a longer lead time to product release – all of which impact cost.

Complexity, costs, and time can be minimized if all colors of an LED had the same focal height, resulting in the same focal length.

Having one focal length for all colors simplifies the design of secondary optics that can consistently blend light to achieve richer, more saturated colors, and more precise color mixing. Employing a single, consistent secondary optics design for light emitted from a single focal length provides a consistent radiation pattern, maximizes optical efficiency, and eliminates high density effects like halos and auras by maintaining light and color clarity from the center to the outer edge of the light beam.

It’s no accident that LUXEON C Color Line and LUXEON CZ Color Line of LEDs from Lumileds all have identical focal lengths – regardless of color. This allows for flawless color mixing and maximum optical efficiency. These LEDs streamline the design of secondary optics for LED lighting, simplifying the production of rich colors with high efficiency and smooth color mixing that’s so important for visual effects and entertainment lighting applications that combine multiple colors in a single design.

There are many specifications that must be met when specifying LEDs for particular applications. Lumileds technology approach is to look for all the factors we can engineer for – even if seemingly obscure – as part of our effort to deliver LEDs that make our customers as successful as possible. The focal height of LUXEON C and LUXEON CZ LEDs is just one example.