from a UK-headquartered expert, this issue can be mitigated. Optical materials are used in the manufacture of items such as mirrors, windows and prisms, and are designed to reflect, transmit, detect and transform light. Included in Ellsworth Adhesives’ diverse range of optical materials are mouldable optics, optical coatings and optical encapsulants from Dowsil (formerly Dow Corning). Dowsil optical materials set out to go beyond the limits of traditional optical materials while not only offering excellent optical properties but also more resistance to impact damage and degradation from UV, heat and environmental extremes. Tese optical materials aim to push design boundaries by enabling LED sources to feature more complex shapes, micro-scale optical structures, multifunction parts and even undercuts that are difficult to achieve with organic polymers or glass.


MOULDABLE OPTICS Mouldable Optics can boost the long- term performance of a design beyond the capability of traditional optical materials. With unique optical properties, they are most resistant to impact damage and degradation from UV, heat and environmental extremes – a key benefit of modern optical materials compared to traditional means. Mouldable optics are also beneficial to the end user in the sense that it allows them to explore more complex designs whilst simplifying the manufacturing process. Dowsil MS-1002 is a mouldable silicone optic designed to produce fine detail with good resistance to environmental aging. It has a medium viscosity for injection moulding, good mould flow and transparency with better heat resistance than plastic and appearing lighter than glass. Tere is also the option to easily mould this material into complex shapes. MS-4002 is a unique material in the range, due to its ability to enable the moulding of complex finely detailed optical parts and secondary lenses. Tis mouldable silicone is a medium viscosity, fast heat curing optical moulding resin with good resistance to environmental ageing. Offering high heat transmittance and low light attenuation coefficient, it allows for better heat and UV resistance than optical


he physical properties of materials can often limit design freedom. However, thanks to a specialised range of optical materials on offer

grade plastics and is especially beneficial for injection moulding of secondary optics, lenses clusters, light pipes, light guides and free-form collimators.

OPTICAL COATING Optical coatings are made up of a combination of thin film layers, designed to enhance transmission or reflection properties within an optical system. Te performance of an optical coating is ultimately based upon the number of layers, which includes the thickness of the individual layers as well as the refractive index difference at the layer interfaces. Dowsil CI-2001 white reflective optical

coating provides even more freedom to go beyond the design limitations of traditional materials. Tis reflective coating

can enhance light output and efficiency in reflectors, lightboxes, mixing chambers, backlight units and other surfaces, while ensuring high resistance to environmental ageing. CI-2001 offers many additional benefits, including additional protection from humidity, moisture and thermal stress, and excellent insulation against high voltages whilst minimising processing costs. At the same time, it eliminates the need for special storage, handling and ventilation.

OPTICAL ENCAPSULANTS Optical encapsulants serve to enhance light output and efficiency in lighting applications. Tese silicone-based products have great compatibility with LED substrates while offering superior thermal stability. With a number of additional

Tom Harrison on overcoming design limitations with optical materials

Dowsil mouldable optics and coatings are designed to meet the challenging needs of the optical market


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