The LEDs density suitable for the Neon LED strip without dots ?

Nowadays, the flexible silicone neon led strips are more and more popular accross the world due to its soft, linear, uniform emission and UV resistance , etc. 

But sometimes customers can find the dots when the silicone neon tubes play colors changing. And I think you would be distressed if the vendors didn't mention this to you. 

So, this topic mainly discuss an important issue on the dots or shadows when we producing the neon tubes.

The dots happened is the LEDs brightness are not enough to cover the luminous surfaces of neon tube. Why the brightness couldn't cover the luminous surface of the neon tube ? Actually, there are many factors like LEDs emitting angle, led intensity, transmittance of neon tube , emitting area of the LEDs and the neon tube sizes, etc. 

Let's discuss one by one:  

1. Firstly, the LEDs emitting angle.         
   •  As we known, most LEDs , its emitting angle are 120° like 5050 LEDs, 2835 LEDs. 
2. Emitting area of the LEDs. 
   • 5050 LEDs, it is 25 mm2 in theory;
   • 2835 LEDs, it is 9.8  mm2 in theory. 
3. Secondly, the led intensity. 
   • It based on the LEDs qty of course when same bin for the LEDs. 
4.  the transmittance of silicone neon tube. 
   • For the white silicone neon tube, normally are 65-70%;
   • For the black silicone neon tube, it would be darker than the white silicone neon tube. 
5. The sizes of silicone neon tube. 
   • There are top emitting, side emitting ,270° emitting and 360° emitting silicone neon tube on market.
   • Multiple sizes for the different emitting silicone neon tubes. 

Then how we can avoid to get the silicone neon RGB / RGBW led strips with dots or shadows ? Of course, we should avoid to produce the neon RGB/ RGBW led tapes with dots too.  To avoid the dots happen, we need to confirm there are enough LEDs brightness to cover the luminous surface. 

Let's take 5050 LEDs as an example below. 

One pcs 5050 RGB/ RGBW LED tape inside the neon tube, currently we do not know the leds density yet. Considering on its beam angle is 120°, we can get an image attached for reference,

• L1: distance of the LEDs;

• L2: Height from the luminous surface of neon tube to surface of 5050 LEDs ;

• L3: Height from the luminous surface of neon tube to surface of 5050 LEDs without dots;

Based on mathematical calculations, when the L3 = L1* √3/2 ， the LEDs brightness can cover the luminous surface of the silicone neon tube. 

From this, we can conclude that in theory,

1. The L2 = L3 = L1* √3/2, the LEDs brightness can cover the luminous surface of the silicone neon tube;

2. The L2 < L3 = L1* √3/2, the LEDs brightness couldn't cover the luminous surface of the silicone neon tube that we can see dots;

3. The L2 > L3 = L1* √3/2, the LEDs brightness can cover the luminous surface of the silicone neon tube that we can't see dots. 

Noted :

Why the L2 = L3 = L1* √3/2, we didn't say, there no dots ?

Because, as we noted before, this is in theory, we should consider other factors like the transmittance of silicone neon tube. 

Take white 16*16 top emitting silicone neon tube as an example: 

LED tapes inside the 16*16 top emitting silicone neon tube, the L2 ( height from the luminous surface of neon tube to surface of 5050 LEDs) is 11.4mm after we measured, via mathematical calculations, the L1= 13.16mm, then the LEDs qty is 76 leds per meter in theory. 

This means, the 5050 LEDs qty, must , at least 76 leds per meter that would without dots happen. 

But considering on the transmittance of white silicone neon tube is 65-70%, plus based on our producing experiences, at least 84 leds per meter that without shadow, of course the more leds per meter, the better . 

We can conclude below : 

1. Same qty 5050 LEDs tape, the higher height of the silicone neon tube, the less dots. 
2. Same height of the silicone neon tube, the more qty for 5050 LEDs, the less dots. 

I think other guys will ask, I calcauted this for 2835, it is nearly same qty with this 5050 LEDs, but why our silicone tubes have many dots ?

Well, there is another factor you missed, the emitting area of the LEDs. 

The mitting area of the 5050 LEDs is nearly dobule than the area of 2835 LEDs. 

So, the 2835 LEDs qty will be double than the 5050 LEDs inside the top 16*16 silicone neon tubes. Like at least 168 LEDs per meter is a good choice. 

Same rules for the side emitting silicone neon tubes . 

We hope this article can help you to get the silicone neon tubes with soft , no shadows. 

Please note, above rule is not suitable for the 270° emitting and 360° emitting silicone neon tubes. 

This result is derived from mathematical calculations and verified by practical from us. Might not the exactly result, but just for referencene. 

If have any info need to be revised or updated, tell us freely. 

Best regards from Art LED Team.