Ambilight is a unique Philips feature, where RGB LEDs are used to create a dynamic light halo around the television.
This extends the screen and hence increases the viewing experience, as it draws the viewer more into the action on the
screen. The feature receives very positive consumer feedback. However, implementing Ambilight in the increasingly
stringent design boundary conditions of a slim and thin TV set is a challenging task. Optical simulations play a vital role
in each step of the Ambilight development. Ranging from prototype to final product, we use simulations, next to
prototyping, to aid the choice of LEDs, optical materials and optical systems during different phases of the design
process. Each step the impact of the optical system on the mechanical design and TV set dimensions needs to be taken
into account. Moreover, optical simulations are essential to guarantee the required optical performance given a big
spread in LED performance, mechanical tolerances and material properties. Next to performance, optical efficiency is
also an important parameter to evaluate an optical design, as it establishes the required number of LEDs and the total
LED power. As such optical efficiency defines the thermal power which needs to be dissipated by the LED system. The
innovation roadmap does not stop here. For future systems we see a miniaturization trend, where smaller LED packages
and smaller dies are used. This evolution makes the impact of mechanical tolerances on the optical design more severe.
Consequentially, this approach poses a whole new challenge to the way we use optical simulations in our design process.
We designed a compact illumination system based on a linear array of single package RGB LEDs which creates a
tailored light distribution. Realistic optical simulations in Advanced Systems Analysis Program (ASAP ®) and
a statistical approach in Matlab ® , are used to investigate the color uniformity. A clear trade-off between the
capability to tailor the obtained light distribution and the color uniformity is found. Two methods to improve the
color uniformity while maintaining the light tailoring capabilities of the optical design, are investigated: mixing
the LED orientations and using anisotropic scattering properties. The aimed application is an illumination
module for Ambilight ® television sets, although the investigated methods can be applied to other LED based