May 19, 2017: Rapid growth of LED technology has incited development of several lighting components. New type of materials are also coming up as material suppliers aim at interior and exterior LED lighting; LED automotive and transportation lighting; LED backlighting for TVs, computers, and smart phones; and LED display lighting for signs and billboards.
All this means more options and new business opportunities for LED lighting component manufacturers.
New materials emerging
A substantial part of the cost of LED lighting manufacturing is due to the choice of materials that make up the LED luminaires, such as aluminum for heat sinks. The enormous majority of LEDs might benefit from the use of plastic materials to increase design freedom and decrease manufacturing costs.
Acrylic and polycarbonate have by and large replaced glass in LED lamps and luminaires. More recently, liquid silicone rubber (LSR) is also being used. While acrylic provides higher light transmission, PC benefits from superior impact power, advanced heat resistance, which are significant for LED lighting.
Additionally, these days there are thermally conductive compounds intended for replacing die-cast aluminum heat sinks.
In order to lessen the blaze of harsh LED lighting, or to offer a wider viewing angle, manufacturers often prefer to diffuse the light emitted. This is attained by adding up diffusion colors to the mass PC, putting in a thin diffusion film behind the lens, or generating a surface diffusion by adding up texture to the molding tool.
The latter two add cost, through extra assembly or tool modification. Now, new diffusion colors are being developed, which offer a wide degree of light management while retaining high transmission. With the diffusive characteristics in the new material, there’s no need for film assembly or mold treatments.
To cut down fixture design cost, Evonik has developed a ready-to-use light-guide panel (LGP) that comes inclusive of an optical-grade acrylic light-guide layer, an already applied white reflector, and custom-printed gradient outline. The innovative LGP offering, Acrylite WH003, permits fixture manufacturers to buy a complete high-quality LGP and employ the whole optical element right into their design.
PolyOne also provides a first-class light-diffusing sheet that can spread 80-90% of light while efficiently diffusing the LED points of light across the lens. UltraTuf LED sheet is rooted in Spectar Stratus copolyester from Eastman Chemical, Kingsport, Tenn.
Material suppliers say the recent types of innovative materials are allowing long-life LED lighting that was not possible earlier for applications like outdoor and technical lighting and automotive. Also, they say that the clearness and color of LSR have been exposed to be minimally affected by exposure to weather. This is mainly applicable for automotive headlamp applications. LSR suppliers say their materials also give more freedom to the designers.
Resin suppliers have been pushing to replace the conventional die-cast aluminum heat sinks. The utilization of plastic heat sinks can help the addition of Bluetooth or Wi-Fi chips for manufacturers who wish to control their lamps through a computer or mobile device, as the plastic can give less signal attenuation as compared to aluminum.
So new materials to make heat sinks are emerging, for instance, a new nylon 6 compound, Durethan TP 723-620, with a high level of mineral back up for thermal management of LEDs and electrical devices has been introduced. This compound is said to offer a combination of properties that leads to outstanding thermal conductivity combined with high light reflection and excellent flame retardance.
Source: Plastics Technology