Hella LED based luminaires are sophisticated opto-electronic devices designed to be highly energy efficient, durable and are a future proof, low ‘Cost-of-Ownership’ solution.
LED based lighting is fast advancing to becoming the logical solution for the cost conscious operator who considers ‘Cost-of-Ownership’ rather than just the initial purchase price. To design efficient LED luminaires many factors need to be considered, the LED itself, optics, optic materials, thermal design and drive electronics. These are among the many factors that add up to result in an efficient and durable luminaire.
• Competent Optic Design
All Hella LED interior luminaires use integrated, highly efficient optic lens designs to accurately capture and evenly distribute the luminous flux emitted from the LED.
• Heat and Thermal Management
Competent and well engineered thermal management is essential for the long-term durability of Hella LED luminaires. A common misconception is that LEDs do not generate heat. LEDs consume power and some of this power is also converted to heat, even in the most energy efficient LEDs. In contrast to incandescent lamps however LEDs do not like to ‘run hot’. As a rule of thumb the hotter an LED runs the faster it will degrade with a lower and in extreme cases, a much lower light performance will result.
High performance LEDs do generate heat, which needs to be coupled to surfaces designed to efficiently transport the heat away from the LED itself. LEDs that overheat, meaning the junction temperature of the LED rises above a set threshold, will permanently degrade and significantly reduce their luminous efficacy.
A noticeably ‘hot to touch’ exterior surface of a high power LED interior lamp provides some indication that the light output of the device will deteriorate fast, sometimes within a few hundred hours. Well engineered LED devices will operate ‘cool’ or ‘warm’ to the touch after many hours of operation.
• Convincing Benefits
Quality LED lighting provides many significant advantages over traditional lighting products. Significantly reduced power consumption, increased reliability, reduction in radiated heat and attractive ambient effects are all benefits of modern LED lighting systems.
• Power Saving
Without doubt, the single most influential driver for LED technology is the considerable power saving on offer compared to incandescent lamps.
Due to the solid state nature of LEDs there are no filaments to break, however LEDs do require precise current control, overvoltage and spike protection to avoid any premature damage.
For LED lighting designers and manufacturers, many design and engineering milestones are required to produce durable products with reliable performance year after year. Considerations such as hermetically sealed housings, sealed cable entries, effective electronic protection, shock, vibration and impact resistant components all contribute towards an LED lamp’s long term reliability. Compared to incandescent lighting, where a filament inside a bulb may break at any moment, Hella LED lighting is designed as a ‘Fit and Forget’ solution.
With significant advances in LED brightness, eye safety considerations are increasingly important. In interior lights it is essential for high power LEDs to be coupled with optic designs that protect the eye’s retina.
It is desirable for a large portion of the lens area of a luminaire to be evenly illuminated via an efficient optic rather than using a bundle of LEDs without any optic. Easily visible LEDs inside a luminaire without any optic or lens protection can cause a degree or even significant eye discomfort if viewed directly.
Quality LED interior and exterior lamps have shifted lighting systems from an incandescent bulb, based inside a housing or reflector to complex engineered opto-electronic devices. These devices now incorporate advanced drive circuits, spike and overvoltage protection, optics, lenses, plus the LED source itself.
As a result, the features and benefits of effective LED lighting do carry higher costs compared to incandescent lamps, however for many applications the efficiencies and reliability gain offset the ‘Cost-of-Ownership’ giving a convincing value proposition.
Hella manufactures LED lamps that equal the performance of some competitors LED luminaires with the Hella product consuming only half the power to achieve this performance. Compared to conventional lamps the power consumption of LED luminaires can be over 80% lower.
The light performance charts show luminance and spread of light in an easy to read format. At the top is the spread, with the boundary threshold being defined as half the peak luminance. While there is light beyond the indicated angles, the majority of light will be inside the cone shown.
The difference between lux (luminance) and lumen (luminous flux) is that lux takes into account the area over which the luminous flux is spread. Accordingly the lux figure decreases with distance.
Most interior lamps will be installed at around the 2 - 2.5 metre height. As a guideline some 40 - 100 lux is required for corridors and passageways, and around 300 lux for reading and 500-800 lux for offices. The Hella spread patterns may not be designed symmetrical so the spread horizontally (H) and vertically (V) are given.
The human eye contains two types of receptors, rods and cones. Both have an increased sensitivity to frequency bands at different ends of the visual spectrum. Rods are largely responsible for our daytime and colour vision and have an increased sensitivity towards the red band of the visual spectrum.
In contrast cones are responsible for our night vision capability and have an increased sensitivity towards the blue, shorter wavelength band of the visual spectrum. For this reason red light helps to preserve our night vision as it will not affect the sensitivity of the cones.