Category Archives: Lenses

10 reasons to choose aLED ALOG100 borosilicate glass lenses

A few years ago we released our own borosilicate glass optics series named aLED ALOG100. This series contains six different glass lenses with angles from 20° to 160°. These glass lenses have so many good features, and in this blog post, you’ll understand why aLED ALOG100 is so popular and why you should really consider them in your next luminaire design.

1. Made of high-quality borosilicate glass

As mentioned already above, aLED ALOG100 glass lenses are made from borosilicate glass. Borosilicate glass is one of the most durable glass materials and it’s known for its light transmittance through the lens compared to plastics and lower-quality glass. Therefore, we can say that borosilicate glass is the best glass material used in glass optics.

Technical specifications for borosilicate glass used in aLED ALOG100 glass lenses

Technical specificationParameter
SiO2 percentage78%-80%
Boron percentage12.5%-13.5%
Deformation point520℃
Annealing point560℃
Softening point820℃
Index of refraction1.47
Light transmittance92%-96%
Elastic modulus76KNmm-2
Tensile strength40-120Nmm-2
Processing point (104dpas)1220℃
Coefficient of expansion3.3*10-6 K-1
Specific gravity(20℃)2.23gcm-1
Specific heat0.9j/(kg·℃)
Thermal conductivity1.2 W·m-1·K-1
Hydrolytic class according to ČSN ISO 7191 grade
Acidic class according to ČSN ISO 1951 grade
Alkaline class according to ČSN ISO 695A2 grade

2. Always true spectrum

Normal lenses and diffusers tend to shift the color temperature of the LED and also the spectrum and color temperature can change at different angles. Because of the high-quality borosilicate glass, the spectrum stays the same at every angle. In addition, the color temperature stays also same.

3. Withstands ultra-high temperatures

These glass lenses can be used even in extreme conditions. High-quality borosilicate glass makes the aLED ALOG100 glass lenses withstand hot temperatures (up to +450°C). This means that these lenses can be used in hot ambient temperatures or with high-power COB LEDs. This gives a great advantage over regular silicone lenses, as they don’t stand so high temperatures.

4. Easy-to-use holder

Borosilicate glass series

All six aLED ALOG100 lenses share the same aluminum holder. This holder is made from high-quality aluminum and has a black anodized coating. Why this feature is important? It gives the possibility to luminaire manufacturers to easily change between different light beam angles, as the different glass lenses share the same screw holes. The designer can design a luminaire for example with a 120° angle, but there is always the possibility to make the same luminaire from angles between 20° to 160°. Even for a small “limited edition” batch as it is so easy to change.

5. High Compatibility with different COB LEDs

Different sizes of COB LEDs are compatible with ALOG100 glass lenses. You must only remember that the LES size can affect how wide the light beam angle is. You can find the chart below how the angles change with standard Citizen COBs. If you use COBs even with smaller LES sizes, like Citizen high intensity COBs, you can have even more narrow light beam angles.

LES ø9,8mm
LES ø14,5mm
LES ø22mm
LES ø32,8mm
ALOG100-140-070-10140140140not applicable
ALOG100 glass lenses with Citizen COBs

6. Easy to recycle

aLED borosilicate glass lenses

ALOG100 glass lens contains only three detachable parts: glass lens, aluminum holder, and silicone gasket. This makes the lens easily recyclable as the doesn’t contain mixed materials that are often hard to recycle.

7. Super high efficiency with borosilicate glass

One of the most important feature of optics is efficiency. In other words, how much light can pass through the optic. aLED ALOG100 glass lens series efficiency is up to 93%. In conclusion, only 7% of the light is lost to the optics.

8. Comfortable antiglare finish

Four of six aLED ALOG100 models have an antiglare finish. Antiglare finish reduces the annoying glare that comes from the luminaire. Luminaires with antiglare optics give a more comfortable working environment. For instance, in warehouses or factory lines, as they don’t irritate the eyes.

9. Flexible product for multiple applications (500lm – 40 000lm)

The first application for aLED ALOG100 glass lenses that comes to mind is of course industrial use, but there are endless possibilities for the series. You can achieve from very narrow light beams to wide light beams that cover large areas. In addition, they can be used with many different lumen packages for example from 500lm to 40 000lm.

10. Long lifetime, no yellowness

One ultimate feature of glass material, in general, is how it will always hold pure color. For instance, some silicone materials will turn yellow in time. The yellowness of course affects the color temperature of the luminaire, so the color temperature can change warmer in time.

Here are only 10 reasons, but I could make plenty more. You can also download a brochure from the link below. From the brochure, you’ll find more precise information about the products and also mechanical drawings. If you have any questions about these glass lenses, you can always email us at

Download the brochure here

product page on our website

Glass Lens vs. Silicone Lens in Street Light

What is the difference between a lens made from optical glass and the lens made from silicon, when used in street light application?

In this blog post, I will explain the pros and cons of both lenses. I will also use a case example to showcase the differences.

The Basics

First let me explain few basic terms related to optics in street light:

Light Pollution

Light that doesn’t go to desired direction and causes harm of anykind. It is wasted light, that isn’t used to its primary purpose. Light pollution can be divided to three different categories:

  • Glare


Discomfort glare results in an instinctive desire to look away from a bright light source or difficulty in seeing a task. So as told by its name, discomfort glare causes discomfort.

  • Uplight

Light Pollution (Uplight/Skyglow)

Light Pollution (Uplight/Skyglow)

Uplight can be seen especially in cities: it makes sky glow and stars disappear.

  • Light tresspass

Light Pollution (Light trespass)

Light Pollution (Light trespass)

Light trespass is found in the vicinity of streets: it can prevent you from sleeping or disturb your garden lighting.

Optical glass


  • Cheap to manufacture
  • Very high temperature range, sensitive also to stress


    • Complex optical shapes can’t be done accurately or if the complex shapes are needed, it is expensive
    • Non-optimal light distribution in street light
    • Heavier than silicone (freight costs are more expensive)
    • Lower light transmission than in silicone lenses




  • Enables high precision manufacturing of complex optical shapes
  • High integration level in luminaire
  • Material weighs less than in case of glass lens


  • Cost is higher than for glass lens

  • Lower temperature range
  • Lower fire rating

Glass Lens

Glass Lens Light Distribution in Street Light Application

Glass Lens Light Distribution in Street Light Application

In the image you can see the light distribution image taken from above. This application uses Glass lens.

      • Boom angle 15 deg
      • 10880 LED lm, eff 88%
      • Eav 9.0 lx (>9.0 lx)
      • Eav/Emin 2.2 (<4.0)
      • Lv max/Lav 0.3 (<0.4)

Silicone Lens

Silicone Lens (Stella DWC2) Light Distribution in Street Light Application

Silicone Lens (Stella DWC2) Light Distribution in Street Light Application

In the image you can see the light distribution image taken from above. This application uses Stella DWC2 Silicone lens.

      • Boom angle 10 deg
      • 8400 LED lm, eff 92%
      • Eav 9.0 lx (>9.0 lx)
      • Eav/Emin 2.3 (<4.0)
      • Lv max/Lav 0.3 (<0.4)


Glass lens needs more lumens for the same application. In this case, around 20% more. This means that you generally speaking need more power to get the same amount of light out from the luminaire.

The reason behind the lumen need is the fact that glass lens generates more light pollution. You can see that the trespass light area is much larger in glass lens image (the red box). And on top of this, glass lens distributes light 10 meters away from road. In comparison, silicone lens only distributes 7 meters.

So I think I can end this blog post by stating that the silicone lens gives a lot of advantages over glass lens in street light application.