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 LSDs 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.

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.

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 angles are available
?

Luminit light diffusers are available in a variety of circular and elliptical angles from 1° to 100° on thin film or rigid substrates.

6. What is the transmission efficiency of Luminit diffusers?


The transmission efficiencies of Luminit LSDs 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?

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

8. Can Luminit LED lighting diffusers reduce hotspots with LED lights?

Yes, Luminit Light Shaping Diffusers 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 LSD 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 a 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 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 LSD’s 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.

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 LSD diffuser replace a secondary optic?

No, an LSD 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

10

12

18.7

15

16.9

22.4

25

27

30.5

40

44.2

45.6

60

65.9

67.8

80

88.2

87.2

60x10

63x12.7

19.1x63.3

60x30

65x32.3

35.1x67

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.  

FAQs on Direction Turing Film (DTF)

1. What is a DTF?

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.

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.

2. What is 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.