Decreasing lighting assembly space – the do’s and don’ts

DO reduce thickness: Reducing the thickness of the lightguide is one of the first places to start when looking to decrease assembly space. One thing to watch for is the potential to start decreasing efficiency while using thinner lightguides, but proper design can alleviate this.

DON’T use LEDs in the illuminated area: LEDs should be placed outside of the visible area in order to maintain and achieve uniformity with illumination. It’s not worth reducing lighting assembly space just to lose uniformity.

DO utilise thinner films: Thinner films also directly correlate to decreased assembly space. It’s important to understand the effects here though. A thinner diffuser may come with reduced diffusive properties, but uniformity can still remain high with well designed extraction features. With thinner back reflector films, the cost of your system may go up, or conversely, efficiency can go down - but either way, it’s potentially an acceptable trade for the reduction in thickness.

DON’T use LEDs larger than the lightguide: This is another way to prevent a mishap. The LEDs should never be larger than the lightguide, as the LED output cone should always be equal to or thinner than the lightguide itself.

DO use other smaller components: There are other components besides the lightguide and the films that can be made smaller. For instance, a flex circuit can be used instead of PCB, and smaller LEDs and LED components can also be put to use. Once again, proper design can still achieve the brightness and uniformity that’s desired.

DON’T risk losing lightguide integrity: If the lighting assembly and the lightguide are unable to maintain integrity, then size has certainly been reduced too much. A certain thickness and size are required to hold everything in place and maintain alignment over time.

DO reduce transition area: Reducing the transition area needed for LEDs is another potential option. By increasing LEDs, dim areas are removed between the LEDs, decreasing the transition area. Further, by adding lensing features to the coupling edge of the lightguide, the transition area can also be reduced without affecting its uniformity.

DO choose the right materials: Using different materials within the lighting assembly can help to reduce its thickness or offer other corresponding benefits. For instance, using metal as opposed to films could allow rigidity into the system without adding significant thickness. And, using polycarbonate instead of acrylic for the lightguide itself can prevent fracturing as thickness decreases.