Eye-Safe Infrared Laser Sensor

Invisible, inherently eye-safe infrared sensing for precision detection.

An invisible, inherently eye-safe infrared laser sensor for precision object detection and ranging — under 0.3 mW, fibre-coupled and miniature (20×10×10 mm), with ambient-light immunity and multi-sensor operation.

Industrial laser sensors for measuring distance or detecting the presence of objects are widely available. However they are usually Class 2 or higher, and therefore not safe for use unshielded in public areas, and they often use visible red lasers. We were approached to design a laser sensor to detect the winning outcome of a roulette wheel. Commercial laser sensors are not safe for this application because the light scatters off highly polished surfaces; casino patrons are at risk of laser exposure above the permitted levels. The red laser is also unsightly and distracting. Our laser sensors use infrared light which is completely invisible. Advanced optical and electronic design allowed us to reduce the power level to less than 0.3mW, making it inherently safe even for continuous direct viewing. Internal monitoring prevents any foreseeable fault from causing an unsafe power output. The detection beam is extremely narrow and focusable, allowing selective detection of the ball in the roulette wheel even in challenging wheel designs, such as those with mirrored or decorated surfaces. Furthermore, the sensor is extremely small, only 20x10x10mm, and is connected to the control electronics by fibre optic, allowing for more ambitious and aesthetic mechanical designs. Orthogonal coding of the light signals provides inherent immunity to ambient light, and up to 8 sensors can be used in a single wheel with no possibility of interference even if the lasers are aimed at each other or at the same object.

Core Capabilities

Inherently eye-safe infrared sensing engineered for precision detection in challenging, public-facing environments.

• Inherently eye-safe — Under 0.3 mW infrared output — safe even for continuous direct viewing, with internal fail-safe monitoring.
• Completely invisible — Infrared beam removes the unsightly, distracting visible-red dot of conventional sensors.
• Narrow, focusable beam — Selective detection even against mirrored or decorated surfaces.
• Fibre-coupled and miniature — 20×10×10 mm head connected by fibre optic for ambitious mechanical designs.
• Ambient-light immunity — Orthogonal signal coding lets up to eight sensors share one installation without interference.
• < 0.3 mW — Optical power — inherently eye-safe for continuous viewing
• 20×10×10 mm — Miniature fibre-coupled sensor head