“Dimming points to a bright future for LED GLS lamps,” explains Andrew Gooding, Technical and Compliance Manager at Integral LED.
No one doubts that LED lighting is on the rise and is effectively eating into the market share of conventional luminaires. Recent reports indicate that LED lighting will grow from a 5% share in 2010 to 45% of the global marketplace by 2020. Yet LED lamp manufacturers are not complacent, they continue to face resistance from consumers, many of whom remain sceptical about the semiconductor-based technology. The look or form factor of a lamp is seen as a key weapon in the battle to win customer acceptance and a new wave of innovative ‘filament’ lamps have arrived that seek to mimic the familiar ‘bulb’ design of the incandescent era.
The science
The recent advent of LED filament lamps now offers the prospect of a true replacement to the incandescent GLS in terms of physical appearance. However, there is a further step in the development of the technology that will make the lamps behave like their incandescent predecessors. Despite their Edison ‘globe’ looks, LED filament lamps have been unable (until now) to operate like incandescent lights, especially when controlled on domestic dimmer circuits. The prize of launching a dimmable LED filament GLS has been hotly pursued by rival lighting manufacturers over the last 12 months; the winning designs are now emerging through distributor channels.
The challenge to assimilate incandescent dimmers is rooted in the deep incompatibility between conventional thermal and semiconductor technologies. It is a difference akin to the fundamental difference between analogue and digital signals. Conventional dimmers operate by simply reducing the current to the heated wire (filament) in an incandescent lamp. This is affected by crudely switching the current off and on rapidly, to starve the power from the lighting circuit. Under this process, the physical dynamic of the heated wire filament emits a constant smooth light. In contrast, an LED array has no latency and will flicker on and off under the same control.
“At Integral LED, our new OMNI range of dimmable LED filament lamps have achieved the goal of a true retrofit GLS in terms of appearance and operation.”
In order to achieve a continuous level of illumination, LED lamps require complex circuitry and components to store a compensatory charge between cycles to maintain a regular and non-fluctuating light. Solutions differ between manufacturer and range from bleeder circuitry, a charge pump and an on-board PWM supply. Yet the challenge remains to accommodate this technology within the small cap of the lamp itself, thereby creating a facsimile of the GLS with which the consumer is familiar.
OMNI range
At Integral LED, our new OMNI range of dimmable LED filament lamps have achieved the goal of a true retrofit GLS in terms of appearance and operation. Only last year we were able to bring a non-dimmable version to market, that had shed the alien looking heatsink. Now we have an LED lamp that dims, whilst preserving the classic looks that Edison would recognise. It has been an intensive journey of replicating the compensatory circuitry and embedding new IC components which have reduced the complexity and space on board. With the introduction of the new dimmable OMNI, we see a new generation of breakthrough LED products that will finally establish solid state, energy efficient lighting as the light source of choice in all UK households.
