This technical note is intended to provide an introduction to beam shaping optical components which can be used with Violumas LEDs.
This technical note is intended to provide an introduction to beam shaping optical components which can
be used with Violumas LEDs.
This technical note is aimed to provide product designers with an introduction to optics, their purpose, and
the factors which need to be considered when using different types of optics.
This resource is intended for engineers using Violumas LED products. Product designers are solely responsible for
selecting the appropriate Violumas products and ensuring that the applicable standards and safety requirements
are met. Violumas cannot be held responsible for any damage caused by following these guidelines.
Bare die, light-emitting diodes (LEDs) without any optics typically emit light at a wide angle, between 120 to 140 deg. This implies that the light is not focused, and the intensity would drop significantly after a certain
distance from the LED. Depending on the application, optics are used to make the optical system work more effectively and to focus the LED beam to a smaller spot. External optics allow for beam shaping to create different light distributions with the same bare chip LED(s). While quartz/fused silica lenses or low-cost silicone lenses are the most popular optics used for UV LEDs, aluminum reflector options may also be available in certain cases. Beam-shaping for UV LEDs may be achieved by using lenses and reflectors or a combination of optics.
Selection of UV-transparent and reflective materials is dependent on the spectral characteristics, UV stability,
refractive index, thermal performance and the associated costs.
Beam shaping optics, if forming a complete seal around the LEDs can, therefore, protect from ingress as well.
Even if beam angle control is not a requirement, flat windows can be used to protect the LED or the LED
array. Figure 1 shows an example of a chip-on-board LED with a fused silica lens.
In this note we will look at various options which may be accessible as beam shaping elements for Violumas products. We will also discuss how these optics can have an impact on the design process.
Beam angle is defined as the angle at which the intensity drops to 50% of the value at the central angle. A
wider beam angle implies a larger spot size, and a narrow beam angle provides more focused light. While
using narrower beam angles may appear more effective, it can also lead to hotspots if the distance between
the LED source and the detection surface is short. For longer working distances, narrow beam angles can
allow for a more focused light. Beam angle for an LED product can be determined from the radiation pattern
typically provided with the LED specifications. Figure 2 shows the radiation pattern of an LED with a 30° beam
angle and a 130° beam angle lens.
Figure 3 shows a comparison of irradiance distributions of a 265 nm LED with two different beam angles- 60°
and 135° at a throw distance of 50 mm
The distribution with the 60° lens is more focused in a certain area while the flat lens is more distributed. So,
when it comes to uniformity a larger beam angle may yield better results at shorter distances. But for longer
distances it is often better to use a narrower beam angle to reduce side emission losses emerging from a larger
divergence angle with greater side emissions. In order to determine which lens would be appropriate for a
certain application, optical simulations may be performed to determine obtainable intensities and uniformity
over a target area. Optical modeling is particularly useful for LED array designs, as overlapping emissions of
individual LEDs should be taken into consideration when selecting the appropriate lens type. In cases such as
curing, high intensities may be required over a small area and so narrow beam angles may be more effective.
However, for applications such as disinfection, a large area distributed source may be necessary.
Another example where optics can significantly aid in reducing losses is where we need to couple light into
a fiber. In this case the light should be almost fully collimated or with low divergence. Figure 4 shows the
radiation pattern from a very narrow beam angle lens (10 deg beam angle) along with a ray diagram showing
how the light beam is almost collimated.
Since the lens is creating a beam with low divergence, the light loss at farther distances is minimized.
Figure 5 shows the irradiance distribution at a distance of 50 mm with a 10 deg lens vs a 120 deg beam
angle lens. It can be seen that the peak power as well as the total power are highly attenuated with a larger
beam angle lens.
Optics play a crucial role in optimizing the design and performance of LED-based systems, particularly by
influencing how light is directed. Incorporating optics may help in reducing the total number of LEDs required
for a specific application. By strategically managing how light is focused or spread, optics ensure more
efficient use of each LED’s output, which can aid in cost savings and reduced energy consumption. When
using Violumas products, the following two approaches may be considered:
The choice between these two approaches ultimately depends on the application-specific requirements. Factors
such as the desired light distribution pattern, the physical constraints of the design, cost considerations, and
the intended use case play important roles in determining the optimal configuration. Figure 6(a) illustrates
the single-lens design of the VC2X2 product, highlighting its simplicity, while Figure 6(b) demonstrates the
standard light bar with individual lenses, emphasizing precision and control.
Violumas offers advanced optical simulation services to help customers design and optimize lens systems
tailored to their specific applications. The company specializes in various lens types, including custom lenses,
Total Internal Reflection (TIR) lenses, and hybrid optical solutions. By leveraging state-of-the-art simulation
tools, Violumas supports the development of innovative lighting solutions across industries, such disinfection,
spectroscopy and curing.
Violumas offers lensed LEDs from 10 to 135 degree in its standard products and can offer custom solutions
based on specific applications.
Violumas proudly offers a wide variety of standard products as well as customized solutions that are tailored to meet your specifications.
