# LGP laser etched dots or v grooves



## anmb (Nov 29, 2017)

Hi I am a newbie working on a side lighting acrylic panel. I have found info on the Perspex acylic panels but cannot find any information on the light guide panel and how the v grooves are calculated from light source to the centre of the panel. Does any body have any simple newbie information? where to look for the info? or explanation of how the spacing of these grooves/dots are calculated before etching?? Perspex seem to be the main suplier of side light acrylic that I have found so far - anybody know of any others?? thanks


----------



## Ozythemandias (Nov 29, 2017)

I’ve seen a number of brands with side lit acrylic, most use a foil backing with texture on it to bounce it forward, some actually embed reflective particles in the panel. Acrylite makes one called EndLighten


----------



## ssanasisredna (Nov 29, 2017)

anmb said:


> Hi I am a newbie working on a side lighting acrylic panel. I have found info on the Perspex acylic panels but cannot find any information on the light guide panel and how the v grooves are calculated from light source to the centre of the panel. Does any body have any simple newbie information? where to look for the info? or explanation of how the spacing of these grooves/dots are calculated before etching?? Perspex seem to be the main suplier of side light acrylic that I have found so far - anybody know of any others?? thanks



Very few lighting panels are grooved. That was more common in the flat panel space.

Most edge lit lighting panels are either screen printed with dots or laser etched with dots. Some high volume ones are molded or roll formed. A diffuse reflective sheet is put behind the acrylic light guide so that the light that is emitted from the optic features that went backwards is redirected forwards. Usually they have a diffuser as well at the front, but not always.

How do they calculate it .... not easily, highly dependent on the optical features, and not something someone who makes those panels is going to tell you.

I don't think Lucite International (Perspex) would even be on the radar for market share for the raw plastic for light guide plates nor the non-patterned plastic sheets.


----------



## anmb (Nov 30, 2017)

ssanasisredna said:


> Very few lighting panels are grooved. That was more common in the flat panel space.
> 
> Most edge lit lighting panels are either screen printed with dots or laser etched with dots. Some high volume ones are molded or roll formed. A diffuse reflective sheet is put behind the acrylic light guide so that the light that is emitted from the optic features that went backwards is redirected forwards. Usually they have a diffuser as well at the front, but not always.
> 
> ...



thanks ssanasisredna
I understand about the difuser and reflective back panel and it is the flat panel space I am interested in. 
The only part I cannot find is the pattern generation/calculation and the difference between dots and grooves. 

On the flat panels I have reverse engineered, they screen print or laser etch the grooved grid/dots on the side light panel.

Do you have any clues as to alternative international manufacturer(s) of the side light acrylic panels, or any clue at all as to where to look to find the pattern generation information for dots or grooves.
I understand that it will be dependent upon the light source values etc. but I am looking for way to calculate the spacings, based on the leds chosen, easily as I am a newbie.


----------



## anmb (Nov 30, 2017)

Ozythemandias said:


> I’ve seen a number of brands with side lit acrylic, most use a foil backing with texture on it to bounce it forward, some actually embed reflective particles in the panel. Acrylite makes one called EndLighten



thanks Ozythemandias
I am currently experimenting with the EndLighten product.
The back engineered panels I have looked at screen print or etch the light guide dots/grooves on this side lit acrylic panel and that is what I am trying to find information about.


----------



## ssanasisredna (Dec 1, 2017)

anmb said:


> thanks Ozythemandias
> I am currently experimenting with the EndLighten product.
> The back engineered panels I have looked at screen print or etch the light guide dots/grooves on this side lit acrylic panel and that is what I am trying to find information about.



May I ask to what end? There are a lot of companies in Asia that will do this process and not charge you for the design.


----------



## anmb (Dec 1, 2017)

ssanasisredna said:


> May I ask to what end? There are a lot of companies in Asia that will do this process and not charge you for the design.



I am experimenting with different leds, different arrangements, different frames etc.
The asian companies supply the readily available led strips glued to the side, use mitred v channel aluminium, and draw amounts of current than may not be necessary for best design - I am trying something new, looking at an extruded frame to include more electronics and less leds. 
That is why I wanted to know about the dots/grooves as I assume the brightness, pitch, size effect how bright and even the end product will be.


----------



## ssanasisredna (Dec 2, 2017)

anmb said:


> I am experimenting with different leds, different arrangements, different frames etc.
> The asian companies supply the readily available led strips glued to the side, use mitred v channel aluminium, and draw amounts of current than may not be necessary for best design - I am trying something new, looking at an extruded frame to include more electronics and less leds.
> That is why I wanted to know about the dots/grooves as I assume the brightness, pitch, size effect how bright and even the end product will be.



I will save you a lot of time:

- The number of LEDs chosen is w.r.t.
- 1) Even lighting at the sides w.r.t. frame width. That is based on LED emission angle and assuming a cheap flat edge LGP
- You can increase the spacing, decrease the frame width by optical features on the edge. Issue is patents + cost
- 2) Efficiency - running the LEDs at lower current increases efficiency

- The only losses in the assembly are:
- Coupling efficiency (big)
- losses in going across the LGP (small)
- losses in light extraction (dots, etc.) -- again small
- diffuser (bigger)

There are expensive things you can do to increase coupling efficiency, but the best is just to get the LEDs right up against the edge but not touching the LGP. To eliminate the diffuser, you need more dots, etc. and may still not get the best effect. Of course, you can create specific optical structures to direct the light which does not get more light out, but does improve usage. That requires molding, not patterning with a silk or laser.

With the LEDs up against the LGP (almost), coupling efficiency is good and fixture efficiency is also good. Small LEDs are cheap cheap cheap. Reducing their number has limited value. Eliminating the diffuser is useful, but may not give the desired "look". Pattern, pitch, etc. of the dots is virtually meaningless as what is there now works, works well, delivers an even panel and has limited impact on the efficiency.

Commercially no one cares about that last few percent efficiency. They want it inexpensive and that is just what flat panels are today.

If you want more detail on anything, standard consulting rates will apply


----------



## anmb (Dec 3, 2017)

ssanasisredna said:


> I will save you a lot of time:
> 
> - The number of LEDs chosen is w.r.t.
> - 1) Even lighting at the sides w.r.t. frame width. That is based on LED emission angle and assuming a cheap flat edge LGP
> ...




thanks again ssanasisredna
good comments, I was perhaps a little niave to think it would be straight forward and I will probably end up buying the low cost asian product, instead of trying to reinvent the technology


----------

