Edge-lit signs :  a cost-effective solution

A new trend in illuminated  signages is in the offing  which incorporates edge-lighting with a new type of acrylic sheet, which gives an ultra-slim effect. The backlit signs are gradually being replaced with such technology-driven signs. The major disadvantage of backlit igns is the use of deep sign cabinets to house lamp fixtures and electronics as well as to minimise heat build-up and surface hot spots. On the other hand, edge-lit signs can be illuminated with a single neon bulb or a string of LED lights, which gives way to a slimmer sign, which requires less maintenance. Another advantage is easy installation as these signs are slim enough, hence the need to recess the sign into the wall, is not required, making them less problematic.

They can be used for traffic sign applications as they provide ultra-bright, uniform illumination of the sign. The technology consists of LEDs mounted along the top and bottom edge of the sign, concealed in the frame. Light is emitted vertically from the top and bottom through a clear acrylic sheet and is refracted outwards horizontally through the sign legend. A high legend-to-background illumination ratio optimises sign recognition and legibility. Acrylic is used because it is versatile and is suitable for both indoor and outdoor applications. It does not turn yellow or deteriorate with age or exposure to outdoor elements. Other features of acrylic include light-weight, break-resistant, which also minimises frequent product replacement. Moreover, it emits 92% light, as opposed to glass which permits only 87% visible light transmission. Besides, the clarity of acrylic maximises brightness, visibility and vibrancy of signs, making the lettering clearer and graphics brighter.

The panels are screenprinted with an array of tiny dots, which reflect light within the panel itself, giving the effect of glowing panel of light. The dots may be printed in a manner that their size increases towards the centre of the panel, increasing reflectivity and compensating for light fall-off. This gives an even surface of light, suitable for back-lighting of transparencies. Depending on the amount of light required, a very slim-line panel can be created. To create a stunning visual effect, colour filters can be incorporated at the top and bottom ends of the panel. Using a mixture of coloured filters, one can create a multi-coloured diffused lighting effect.

Since the acrylic sheet is clear and uncoloured even when illuminated, the panels can be seen through. This gives a degree of visibility to the surface behind, enhancing the visual appearance of the installation. A new trend in acrylic is now seen incorporating neutral-coloured particles in its formulation, which ensure that the light distribution is extra-bright and uniform, without affecting the colour of the sign.

It is recommended that the distance between the light source and edge of the acrylic sheet must be less to ensure that maximum light enters the sheet. Alternatively, a light source needs to be provided with a reflector. For better illumination, edges that are not lit are normally covered with reflective material, such as adhesive tape, etc.

Sign-makers can also choose from varied performance options such as UV filtering which prevents fading of graphic panels behind acrylic sheet. Other options include special surface treatments such as scratch-resistance coating and non-glare finish. Besides, they are available in a variety of colour options, which resist fading. These acrylic sheets can be combined with coloured neon, LED and other lighting to attain distinct colour blends.

Edge-lit signs are easy to install as they have little hardware and could be easily mounted on walls and stands. Hence, they find optimal use in high-traffic zones with limited space, such as bus q-shelters. The interior graphic panels of an edge-lit sign can be easily replaced, thus providing convenience to the advertisers at large.