FAQs on Light Shaping Diffusers (LSDs)

1. What is a Light Shaping Diffuser?

Light Shaping Diffusers are micro-structures pseudo-randomly embedded on a substrate (such as film). When applied to a lighting structure, the LSD can manipulate light by changing the direction of its energy. This allows our Light Shaping Diffusers to clean up and shape a light beam to suit a particular purpose.

2. Where are your optical diffusers used?

LSD are often applied in architectural lighting, can lights, decorative lighting, pool lighting, set/event lighting and wall wash lighting where the effects of LSD can be quite dramatic. LSDs are also used in illumination systems such as aircraft inspection lights; backlit systems such as cellphone and PDA displays; LCD screens and more. One of the most common uses for our light diffusers is to eliminate hot spots on LED light strips. 

3. What sizes of LED light diffusers are available?

Thin-film LSDs are available in rolls, sheets or parts cut to your specifications. Standard rolls are 20” wide and 500’ long. Strip rolls are also available in your specified width. 24"x 24" rigid sheets are available on polycarbonate in various thicknesses. Contact sales for a quote. 

4. Are the diffusers available for smaller applications?

Yes, Luminit Light Shaping Diffusers are available in various circular and elliptical angles in pre-cut sheet format for lower volume applications.

5. What diffusion angles are available?

Luminit's unique LED optical diffuser material is available in a variety of circular and elliptical angles from 1° to 100° on thin film or rigid substrates. Standard angles include: 80ºx50º, 60ºx10º, 80º, 60º, 40º, 30°, 20°, 10°, and 5°. We also offer non-standard angle including 1°, 2°, 3.5°, 30°x 35° 40° x 1°, 60° x 1,  69x 30°, 75 x 45, and 90 x 10.

6. What is the transmission efficiency of Luminit diffusers?

The transmission efficiencies of Luminit optical diffusers are rated between 85-92% (depending on the angle). This very high-efficiency rating is due to the fact that our technology is based on diffractive microstructures. Smaller angle diffusers have the highest transmission.

7. Is the angle of diffusion and transmission wavelength dependent on a Luminit holographic diffuser?

Since our microstructures are random and non-periodic, the LSD is not wavelength-dependent, so it works well from 400nm to 1500nm.

8. Can a Luminit LED lighting diffusers reduce LED hotspots?

Yes, Luminit Light Shaping Diffusers are commonly used as an LED strip light diffuser to eliminate the hotspots without a significant reduction in the amount of the light, provided that the diffuser is placed a sufficient distance from the LEDs. A rule of thumb is that the diffuser must be at least as far away from the LEDs as the LEDs are spaced apart.

9. Can Light Shaping Diffusers shape light beams?

Yes, Luminit optical diffusion films are so precise that beam shaping is possible. Our patented holographic master recording process allows a variety of circular and elliptical light patterns. Standard circular angles range from 0.5˚ to 100˚ FWHM. A wide variety of standard elliptical angles, ranging from 10˚x0.2˚ to 95˚x35˚, are available.

10. What does FWHM mean?

FWHM is an abbreviation for Full-Width Half-Maximum which is the angle of diffusion that would be seen after a collimated laser passes through the diffuser.

11. How long does the LED light diffuser last?

For indoor applications, LSD would last as long as the light structure. For outdoor applications, measures may need to be taken to prevent  yellowing of the film due to exposure to the sun. For outdoor lighting applications, Luminit offers an optional UV-stable substrate to help prevent yellowing.

12. Should I face the diffuser towards or away from the light source?

The diffuser has improved transmission characteristics if the microstructure side is facing the light source, but it has better source hiding characteristics if the microstructure side is facing away from the light source.

13. How should I handle the diffuser and can I clean it if it gets dirty?

We suggest you handle the diffuser with clean latex gloves. High angle diffusers are very prone to damage due the height of the microstructures. They can be cleaned carefully using optical wipes and ethanol using the industry-standard “drop and drag” technique.

14. How do I mount the diffuser in my system?

We recommend you find a mechanical means of securing the diffuser into your system, for example using the natural tension of a film on curved surface. We offer pressure-sensitive adhesive (PSA) as an option but this process is difficult and you may experience the incorporation of air bubbles during the lamination process.

15. Does the angle of diffusion or transmission change if I use a thicker LSD diffuser? 

No, since our technology is based on a surface relief pattern, these parameters are not dependent on the thickness of the substrate. However, there are inherently additional transmission losses if very thick substrates are utilized (Beer’s Law).

16. What is the effective working distance of the diffuser to eliminate hotspots under direct view?

This depends on the angle of divergence and spacing of the light sources. With 110° Field of View, surface mount LEDs, the relationship is around 1:1. That is, if the LEDs are spaced 1 inch apart then you will need a little more than 1-inch distance from the LEDs to our largest diffuser angles. Here is an illustration demonstrating the ratios with various angle diffusers.

ratio of LEDs and diffusers

17. How can I determine which angle will work for me? 

Luminit offers a sample page with 9 samples about 1” square as well as larger A4 sized sheets of select single angles on 0.010” thick polycarbonate. Please select Request a Sample on the Luminit home page. While we do offer this complimentary kit to qualified customers, a UPS, FedEx or DHL account number is required. 

18. Can the light diffuser replace a secondary optic?

No, a diffuser cannot decrease the divergence of a light source. It can only increase its angle of divergence.

19. Are your Light Shaping Diffuser sheets thin enough to cut with everyday tools?

Yes, Luminit’s .010” thick diffuser can be easily cut with ordinary scissors.

20. Are Luminit Light Shaping Diffusers RoHS compliant?

Yes, our LSDs comply with RoHs standards. An environmental compliance statement can be downloaded here

21. Is there a way to determine the beam angle that will result from using a Light Shaping Diffuser?

This will depend on the secondary optics you are using; however, the following chart can help determine the resultant beam angle. 


Resultant Beam

Resultant Beam

Diffuser FWHM

w/ 8.2 degree Optic

w/ 16.4 degree Optic


























22. Are there any modeling programs available to determine which Luminit diffuser angle I should use? 

Yes, but currently only for Zemax OpticStudio. Visit DLL downloads on our Downloads section to learn more.

23. Is it possible to increase this transmission by adding an AR coating on one or both diffusor sides? 

Yes, we are able to increase the transmission by adding AR coating to both sides of our diffuser having the percentages 95~98 depending on the beam angle.  Our microstructures are refractive, so the performance will be constant up to ~1200nm.

24. Do you make diffusers for laser projectors?

Yes, we have glass diffusers that are used in laser projector systems, including glass-on-glass Light Shaping Diffusers as well as our monolithic glass light shaping diffusers (MG-LSD). MG-LSD is a lower cost option but has a higher minimum order quantity (MOQ). Our glass-on-glass diffusers are available in angles ranging from 0.5° to 80° FWHM and sizes up to 200mm x 200mm. With our MG-LSD, we can achieve 1° to 15° FWHM and sizes up to 100mm x 100mm.

25. Are there diffusers for machine vision applications?

Yes, we offer elliptical diffusers for machine vision in angles ranging from 1° to 90° on either axis.

26. Does Luminit have a diffuser for sensor applications?

Yes, we have diffusers with an elliptical and circular spread that can be used on sensors, LEDs and laser sources.

27. Do you have a near Lambertian diffuser?

Yes, our 100° is considered super-Gaussian.  

28. Are any of your optical diffusing films UL rated?

Yes, we have several flame-rated substrates such as VTM-2 and V-0 that are thin films (0.010" thick) polycarbonate.

29.  What is the difference between Luminit Monolithic Glass Diffusers and High-Temperature Glass on Glass Diffusers?

Luminit Monolithic Glass Diffusers (MG-LSDs) are made with an etching process, while our Glass on Glass light diffusers have pseudo-random microstructures that are cast and cured onto the surface of the glass. Temperature is one of the factors that differentiate the two. Our Glass on Glass diffusers are stable up to 500° C and are suitable for high-temperature laser applications. Monolithic glass is also rated for high temperature but is more suitable for lighting applications. 

30. What is the blue protective film on the diffuser and when should I remove it?

Our blue protective film is used to protect the diffuser during transit to reduce the chances of scratches. We advise customers to remove the film within three months of arrival. The reason for this is that there is a chance that the adhesive on the film can cure or harden and stick to the diffuser.

31. Are Light Shaping Diffusers waterproof?

While our LED diffuser sheets are often installed in outdoor environments, they are not waterproof. Submerging the diffuser film or sheet in water would dissolve the microstructures and render the diffuser unuseable.

32. What materials are available for your LED diffusers?

Luminit replicates diffusers on polycarbonate and acrylics (PMMA). We can also replicate our diffusers on glass products.

33. If the AOI is non-zero (15deg, 30deg, 45deg, etc), does the light get diffused into a cone about the surface normal with the transmission efficiency decreasing with increasing AOI or does the light get diffused into a cone about the transmitted ray direction that is equal to the AOI with the transmission efficiency decreasing with increasing AOI?

The light will follow the specular ray. When the AOI is non-zero, the distibution center will follow the transmitted direction. The Zemax models we provide offer a good prediction of the ray distribution. You can see the light path and distribution patterns.

FAQs on Prismatic Films

1. What is a Direction Turning Film?

Luminit’s DTF (Direction Turning Film) is a non-symmetrical linear micro-prismatic that imparts a 20-degree shift in the angle of a semi-collimated light source. The DTF works well with LED light sources that utilize secondary optics. Some applications include recessed can lights to allow for more wall washing, pathway/stair lighting to reduce glare and increase ground illumination, and pool lighting to increase illumination of the bottom.

2. How Do DTFs work with LSDs?

Direction Turning Films can be combined with Light Shaping Diffusers to shape and homogenize the beam in addition to changing the direction. The beam can be shaped in a circular or elliptical pattern dependent on the diffuser angle chosen. These light bending films enable off-axis placement of the incoming beam when direct line of sight is impractical. Applications include LED lighting, avionics displays, traffic signs/displays and LCD backlights. They are also used to change the light beam direction to light a wall, walkway or other lighting target.

3. Can we model the diffuser in optical software?

Yes, we have BTDF data that is convertible to a variety of formats in the downloads section of this website.

4. How linear is the transmission and diffusion angle with drive signal?

The diffusivity has a natural “sigmoidal” (i.e., “S” curve) response to drive signal strength.

5. What angles of diffusion can I achieve?

You can achieve a range of angles from 1° FWHM in the clear state to 70° FWHM in the fully diffused state.

6. What is the transmission of the EVD-M?

The EVD unit has an 81% transmission efficiency in the “on” state and 78% in the “off” state measured at 550 nm at 28°C. Anti-reflection coated glass laminates are available on a special order basis to improve transmission.

7. What types of DTF do you offer?

There are currently two different types of DTF products, one is a 20⁰ bend-off axis material for visible or white light and the other is a 10⁰ bend-off axis for 810nm (IR) LEDs.

8. Can Direction Turning Film direct light onto stage participants and less into the audience?

Yes, our Direction Turning Film is often used to redirect light to a desired location.

9. Can you couple layers of DTF to bend the light even further?

Yes, you can layer multiple sheets of DTF to increase the angle of redirection; however, there will be significant transmission loss.

10. What is Display Brightness Film?

Our display Brightness Film (DBF) is a light management film that increases the brightness of LCD displays. DBF is a prismatic structure with either a 1, 2, 3.5, 10 or 20-degree diffuser on the other side of the film. DBF is also available without the diffuser.


FAQs on Light Diffusing Film for Automotive Applications

1. How are your diffusion films used in automotive lighting?

Automotive lighting engineers incorporate our diffusers into taillights and running lights to homogenize the output of LEDs as well as control the beam angle. If you've seen a recent model Dodge Durango while driving at night, you've seen our diffusers in action. Luminit light bending diffusion films are also used in automotive interior lighting, cluster panels, LCD displays, welcome mat lighting and more.

2.  Are your diffusers rated for automotive lighting?

Yes, our lighting diffuser film is approved by AMECA as meeting the three-year weathering test of SAE J576 for plastics used in optical lenses and reflectors on motor vehicles.

FAQs on Edge-lit Uniformity Tape

1. What does Edge-lit Uniformity Tape do?

EUT solves common problems associated with widely-spaced LED lighting. These problems include hot spots and other non-uniform characteristics that can be visible on the edges of LED flat panel TVs, as well as edge-lit lighting fixtures. Keep in mind that, while we have EUT in stock, only the 3.8mm is available to ship.

2. What is the transmission rate of EUT?

Transmission is greater than 88%

3. How much gap is required between the EUT and the LEDs to be effective?  

For the most effective results, the gap should between 5-10mm.