JOKER table luminaire by Regent Lighting – perfect light at the workplace thanks to unique light guides made from PLEXIGLAS®

Bad lighting results in poor work. Office work is very tiring under unfavorable lighting conditions, as anybody who has worked from home for a longer period of time without ergonomic office equipment can attest to. It is almost impossible to concentrate if a table luminaire causes glare, only illuminates half the desk, is in the way or blocks your view of a monitor.

The Swiss lighting manufacturer Regent Lighting developed the JOKER table luminaire with the aim of bringing a professional luminaire to market which provides pleasant lighting for those working from home – in close collaboration with Jungbecker, a company from Olpe which specializes in plastic optics. Their material of choice for the optics is PLEXIGLAS®, the brand polymethyl methacrylate (PMMA) from Röhm.

Unique optics made possible with PLEXIGLAS® molding compound

JOKER stands out from traditional table luminaires with its one of a kind, patent pending, lighting technology. This elegant, rectangular luminaire stands upright and can be moved freely around a desk, evenly lighting the workplace without casting multiple shadows. A micro-structured light guide made from a highly transparent PLEXIGLAS® molding compound is integrated into the very slim body of the luminaire. The unique construction of the optics allows the luminaire to emit a pleasantly soft and glare-free light from the vertical area, lighting the workspace in a highly efficient manner at an unconventional beam angle from the side.

The optical system that creates this effect consists of a v-shaped light guide with lateral coupling collimators which focus the light rays, as well as a planar microstructure. They are optimized and combined in such a way that distributes the light downwards asymmetrically, thereby preventing glare. The work surface of 60 x 60 centimeters is homogeneously illuminated at the desired level of illumination up to 600 lux.

The integrated Tunable White technology makes it possible to control the color temperature steplessly at the push of a button. This not only makes working at home more pleasant but enables everyone to work with the light that they prefer even in a large open-plan office.

Reduced form, high functionality

“We did not want to design the 550th table luminaire with a swivel arm, but come up with something completely different,” says Kornelius Reutter, Project Manager for Design and Innovation at Regent Lighting. “Especially since the technological advancement with LEDs and optics allows for shallow constructions which are favorable to shapes that are in line with the Regent Lighting design philosophy: timeless, clearly designed luminaires with highly intelligent lighting technology.” With his designs for JOKER, Reutter followed three guiding principles: Light is simple. Light is personalized and serves people. And the luminaire fits in harmoniously with the architecture and the space.

Light area inspired by infinity pools

The designer got his inspiration for the surface light from infinity pools – fascinating swimming pools in which the water appears to be contained without a visible barrier. The implementation was successful: when the luminaire is on, the view is of a free-floating, homogeneous light area. The frame of the light guide made from PLEXIGLAS® is barely visible. It is just as surprising that no light emission is visible from the side.

This innovation is the result of the high demands Regent Lighting places on light design, the development and processing skills of Jungbecker and the optical properties of the PLEXIGLAS® molding compounds from Röhm. “It is crucial that the material absorbs as little light as possible. Highly transparent PLEXIGLAS® is ideally suited here,” says Fabian Bürkli, Project Manager for Research & Development at Jungbecker.

“With a light transmittance higher than 92 percent, PLEXIGLAS® is one of the most transparent materials,” describes Dr. René Kogler, Head of Product Management for Lighting, Extrusion, Optics at Röhm. “The transparency is only reduced by the physically induced reflection loss of four percent each on the light entry and exit surfaces. This is why our PLEXIGLAS® molding compounds are in high demand as a material for highperformance optics.”

Extremely fine microstructures through hot stamping

The optics for JOKER are produced in a special production process. In the first process step, the PLEXIGLAS® molding compound is made into a v-shaped blank with small cones at the thicker end, the optical couplings for the LEDs. In the second step, extremely fine microstructures are stamped into the light guide in a hot-stamping process.

“Our years of experience with the hot stamping technology allow us to precisely control the point and angles at which light is emitted by the component,” explains Bürkli. Despite this expertise, the extraordinary complexity of the light guide for JOKER presented an extreme challenge, as the goal was for the asymmetric light distribution to illuminate as much of the work surface as possible without causing glare. “Together with Regent Lighting, we tested the boundaries of what is possible,” he states. Reutter emphasizes: “I knew that it was theoretically possible to achieve this degree of precision, but it is fantastic when everything works in reality as well as in planning. And this is also due to PLEXIGLAS®, as it has excellent optical values and can be processed very precisely.”