Light guide technology

Light guides from Printec-DS

The use of light guides for key lighting ensures the optical wow effect in many keyboards and customer-specific input solutions. The key factor here is how light guides are used. Because the controlled passage of light through a plastic conductor requires a lot of know-how and development work. The effort is worthwhile, however, since an optimally adapted light guide provides a means of homogeneously backlighting larger areas through the light of a single or fewer LEDs. In the long term, the development of a light guide can be worthwhile, since the reduction in the LEDs installed on the circuit board and the inexpensive reproduction of the light guide save manufacturing costs.


3D modeling

As a rule, a light guide must be integrated into an existing concept. The arrangement of the buttons should not change and the space available is usually very small. Nevertheless, we always succeed in finding a suitable solution that does not restrict the functionality or the design of the planned product. Combining these requirements in a small plastic light guide is the highest level of development and is realized by our construction with the help of modern applications in the form of a 3D model. Based on this model, a light guide calculation can be carried out and the later component can be produced.

Figure of a light guide from two sides

Light guide calculation

With the help of light guide calculations, the light scatter can be determined before the first component has been manufactured. The calculation is carried out using special programs and outputs the result of how the light will move in the light guide and how intensely it radiates outwards on the visible surfaces. If shadows, hot spots or other disturbances in the homogeneity are noticed due to the calculation, the 3D model can be adapted on the basis of the calculations and the arrangement of the LEDs on the circuit board can be checked. This development step means that there are no repeated costs for the production of prototypes that do not meet the requirements for light distribution.

Figure of a light guide calculation


If the light guide calculation delivers a satisfactory result, the first samples can be produced. 3D printing and vacuum casting processes are used for this. The resulting samples can then be tested under real conditions in the prototypes and on the test bench before the injection molding process can be started. This means that large quantities can be produced in a short time and at low costs, so that the development can often pay for itself within a short time.

 Die fertigen Lichtleiter - links mit Lichtschott, rechts ohne

The finished light guides - left with light barrier, right without