In outdoor lighting, the choice of optical lens plays a decisive role in both performance and efficiency. "T2M" is one of the most frequently mentioned terms in street and area lighting design, but what exactly does T2M stand for? Why is it so important to lighting engineers and project planners?
What is T2M in optical lens design?
T2M stands for Type II – Medium, a photometric distribution type defined by the Illuminating Engineering Society of North America (IESNA) that describes the shape and range of a luminaire's light intensity distribution.
Unlike a symmetrical beam, a Type II distribution's light intensity is not directed directly below the luminaire, but slightly outward, forming an asymmetrical, elliptical pattern. Medium (M): The beam has a moderate spread in the direction of the road.The beam spot is longer perpendicular to the road and shorter parallel to the road. The maximum light intensity is located at an angle (e.g., 25°-30°) to the road, rather than directly below (0°).
This design effectively "throws" light energy toward the center of the road, rather than wasting it on the outer sidewalks or roadside green belts, resulting in higher utilization and energy savings.
The Importance of T2M in Street Lighting Applications
T2M (Type II) light distribution is ideal for the following scenarios:
- Residential streets and community roads.
- Lighting layouts where poles are located on the side of the road.
- Applications where the road width is approximately 1.0 to 1.75 times the mounting height.
- Medium-width roads, side roads, park paths, parking lot driveways, etc.
The 4in1 LED lens is a compact optical module that integrates four LEDs into a single lens unit. Combined with the T2M photometric design, it provides efficient directional lighting for outdoor applications.
By using a 2x2 T2M lens, lighting designers can ensure a balance between efficiency, safety, and glare reduction, which means better visibility for drivers and pedestrians and greater energy savings for municipalities.
Thus, T2M is a type of photometric distribution defined by the Illuminating Engineering Society of North America (IESNA) to describe the shape and range of a lamp's light intensity distribution. 4in1 T2M is widely used in outdoor street lighting. If you have an outdoor lighting project, please discuss it with the Asahi team!