3W 810nm 3535 SMD Infrared LED: A Comparison of 30°, 60°, and 120° Dome Lenses
This family of SMD LED infrared LEDs is built on the standard High power LED 3535 ceramic substrate (3.5 mm × 3.5 mm) and delivers 3 watts of optical power at a peak wavelength of 810nm LED, which lies in the near infrared region invisible to the human eye. The package uses a silicone dome lens, gold wire bonding with 99.99% purity, and a ceramic base for excellent heat dissipation, ensuring stable performance across an operating temperature range of –40°C to +80°C. The only difference between the three variants is the beam angle of the dome lens, which fundamentally changes how the emitted light is distributed in space.
The 30° dome lens produces an extremely narrow and highly collimated beam. This design concentrates most of the infrared energy into a very small solid angle, resulting in the highest on‑axis radiant intensity among the three options, typically around 150 milliwatts per steradian. As a consequence, the illuminated spot is small, but the effective range is the longest. This makes the 30° variant the first choice for long distance surveillance cameras, iris and facial recognition systems, finger‑vein authentication, and any application that requires precise, laser‑like projection of infrared light over tens of metres. However, the narrow beam means that coverage area is limited, so it is not suitable for illuminating wide scenes.
The 60° dome lens strikes a middle ground between beam concentration and coverage. It offers a noticeably higher on‑axis intensity than wider angles, while still spreading the light over a moderate field of view. This balance makes it ideal for mid‑range CCTV cameras, machine vision systems that require a focused yet somewhat broadened illumination, spot lighting in stage or industrial settings, and medical instruments where a controlled but not overly tight beam is needed. The 60° version sacrifices some maximum range compared to the 30° but gains a more usable spot size for medium distance targets, making it the most versatile choice for many security and inspection applications.
The 120° dome lens produces a wide, diffuse flood beam that spreads infrared light evenly over a large area. On‑axis intensity is the lowest of the three, but the coverage area is the broadest. This lens is the standard for general‑purpose infrared illumination, such as fill‑light for CCTV cameras covering wide scenes, night vision lighting for parking lots or large rooms, panel lights, and machine vision setups that require uniform illumination across an entire work surface. The 120° beam is excellent for short‑range, wide angle applications where consistent lighting across the field is more important than peak intensity at a single point.
In terms of electrical characteristics, all three variants share the same typical forward voltage of 1.5 to 1.6 volts at a driving current of 1000 milliamperes, with a maximum forward voltage of 1.8 volts. The reverse current is negligible, and the peak wavelength is tightly centred at 810 nanometres IR LED with a tolerance of ±5 nanometres. Total radiant output power varies slightly with the lens design due to optical extraction efficiency, but typical values range from 300 to 800 milliwatts at rated current, with the 30° version often delivering the highest peak intensity per unit of power.
Choosing the right lens angle is simply a matter of matching the beam to the application. For extreme distance and pinpoint targeting, the 30° is unbeatable. For a compromise between reach and coverage, the 60° is the workhorse. For wide, uniform illumination of close‑range scenes, the 120° is the obvious choice. All three are available in the same compact 3535 SMD LED package, and many suppliers can also offer customised beam angles upon request, making this LED platform highly adaptable to a variety of infrared lighting needs.