LED test / review Osram SYNIOS P2720 DMLQ31.SG white - Small chip, but big in luminance - at low current!

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EasyB
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The_Driver wrote:
EasyB wrote:
Enderman wrote:

Fortunately this is just for the synios LEDs, all other LEDs are fine and the results are still correct Smile

Actually many LEDs will have a problem with this method of calculating luminance. Any light that you see not coming from the die itself will inflate the calculated luminance. To name a few: XPG3, XPL2, luxeon V, nichia 219C, XHP50.2, XHP70.2.

That being said I find koef3’s detailed pictures and measurements to be very useful. But for the luminance measurement I think a careful in-flashlight test will give a more accurate result.

Are you sure about the 219C?


Yes, I measured the bare die luminance of the 219C and observed the in-flashlight results were much less. This was before I discovered this stray light effect in my investigation of the XPG3, so I didn’t understand the discrepancy then. But if you look at the dedomed 219C the white area around the die is significantly lit.
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The_Driver wrote:
EasyB wrote:
Enderman wrote:

Fortunately this is just for the synios LEDs, all other LEDs are fine and the results are still correct Smile

Actually many LEDs will have a problem with this method of calculating luminance. Any light that you see not coming from the die itself will inflate the calculated luminance. To name a few: XPG3, XPL2, luxeon V, nichia 219C, XHP50.2, XHP70.2.

That being said I find koef3’s detailed pictures and measurements to be very useful. But for the luminance measurement I think a careful in-flashlight test will give a more accurate result.

Are you sure about the 219C?


In my led surgeries it appeared that the 219C is different from the old Cree leds like XP-G2 in that the phosfor is not a compact rigid layer right on top of the light emitting surface, but a layer of phosfor mixed silicone that is inside a white-coloured shallow square cup surrounding the die. On top of that I assume that it is a flip chip design so the light does not enter the phosfor containing layer directly, but passes the die base first.
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EasyB wrote:
The_Driver wrote:
EasyB wrote:
Enderman wrote:

Fortunately this is just for the synios LEDs, all other LEDs are fine and the results are still correct Smile

Actually many LEDs will have a problem with this method of calculating luminance. Any light that you see not coming from the die itself will inflate the calculated luminance. To name a few: XPG3, XPL2, luxeon V, nichia 219C, XHP50.2, XHP70.2.

That being said I find koef3’s detailed pictures and measurements to be very useful. But for the luminance measurement I think a careful in-flashlight test will give a more accurate result.

Are you sure about the 219C?


Yes, I measured the bare die luminance of the 219C and observed the in-flashlight results were much less. This was before I discovered this stray light effect in my investigation of the XPG3, so I didn’t understand the discrepancy then. But if you look at the dedomed 219C the white area around the die is significantly lit.

Did you post these results anywhere?
I have been thinking about tuning my Noctigon Meteor with dedomed 219Cs. It currently has de-domed 219Bs.

EasyB
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Some 219C measurements:
http://budgetlightforum.com/comment/955455#comment-955455

I measured 300Kcd at 5.5A in a UF1504, which has a 3019 mm^2 lens.

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EasyB wrote:
Some 219C measurements:
http://budgetlightforum.com/comment/955455#comment-955455

I measured 300Kcd at 5.5A in a UF1504, which has a 3019 mm^2 lens.

Thanks, I used your numbers to determine the luminance of the 219C D240 (R9050) shaved at 2A: 41.8cd/mm^2. With 12 of these and
UCLp lens the Meteor should do 34kcd. Thats not too bad. The 219Bs do 20kcd with dome and are probably similar without. I really like the beam profile and throw, but higher efficiency would be really nice (especially less heat!).

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The_Driver wrote:
EasyB wrote:
Some 219C measurements:
http://budgetlightforum.com/comment/955455#comment-955455

I measured 300Kcd at 5.5A in a UF1504, which has a 3019 mm^2 lens.

Thanks, I used your numbers to determine the luminance if the 219C D240 (R9050) shaved at 2A: 41.8cd/mm^2. With 12 of these and
UCLp lens the Meteor should do 34kcd. Thats not too bad. The 219Bs do 20kcd with dome and are probably similar without. I really like the beam profile and throw, but higher efficiency would be really nice (especially less heat!).


Using your calculations I get peak 154 cd/lm for D320.
Assuming current-handling of 219D is the same (yes, I know how good this assumption is), it should do 210 cd/lm 195 cd/lm in D340 bin. This number may be way off, but I believe 219D is worth testing. Wink
The_Driver
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Why should cd/lm be higher with the new LED? It’s probably the same or worse.

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The_Driver
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Agro wrote:
See http://www.nichia.co.jp/en/product/led_product_data.html?type=%27NVSW219... and http://www.nichia.co.jp/en/product/led_product_data.html?type=%27NVSW219... They state “Luminous Intensity”. Also, you can see a smaller die on the photo.

Thanks! I didn’t notice that before. That’s seems to be quite a nice upgrade! The brightness increase (3.7%) is negligible though.

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EasyB wrote:
Some 219C measurements:
http://budgetlightforum.com/comment/955455#comment-955455

I measured 300Kcd at 5.5A in a UF1504, which has a 3019 mm^2 lens.


Is that taking into account the clear aperture of the lens?
Lenses usually have 95% CA, or even less for cheaper quality ones.
The outside circumference is not very aspherical and therefore may not contribute to the lux in the spot.
The best way of being sure is putting a circle of paper or metal in front of the lens which has a smaller diameter than the lens, in order to ensure you’re only calculating lux and area for the clear aperture.
EasyB
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Enderman wrote:
EasyB wrote:
Some 219C measurements:
http://budgetlightforum.com/comment/955455#comment-955455

I measured 300Kcd at 5.5A in a UF1504, which has a 3019 mm^2 lens.


Is that taking into account the clear aperture of the lens?
Lenses usually have 95% CA, or even less for cheaper quality ones.
The outside circumference is not very aspherical and therefore may not contribute to the lux in the spot.
The best way of being sure is putting a circle of paper or metal in front of the lens which has a smaller diameter than the lens, in order to ensure you’re only calculating lux and area for the clear aperture.

Based on looking into the front of the lens from a distance, nearly the full 62mm diameter is active. This area estimation seems to give a consistent measure of the dedomed xpg2 luminance at 510Kcd at 4ish amps.

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EasyB
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The_Driver wrote:
Agro wrote:
See http://www.nichia.co.jp/en/product/led_product_data.html?type=%27NVSW219... and http://www.nichia.co.jp/en/product/led_product_data.html?type=%27NVSW219... They state “Luminous Intensity”. Also, you can see a smaller die on the photo.

Thanks! I didn’t notice that before. That’s seems to be quite a nice upgrade! The brightness increase (3.7%) is negligible though.

I assume that “luminous intensity” is the cd measured directly above the LED. That does not necessarily indicate a higher die luminance. The fact that the 219c and 219d have different proportionalities between the intensity and lumen output means they have different emission patterns, which is supported by their different quoted “directivity” angles in the links above. So the 219d simply has a different shaped dome which directs more light forward.

Also your estimated luminance of 154cd/mm^2 for the 219c d320 seems high. My measurement in the UF1504 puts the effective luminance at 100cd/mm^2 at 5.5A. Assuming 90% lens transmission that is 111cd/mm^2 die luminance. And according to Texas ace’s test of this LED the max output is only 5% greater than the output at 5.5A.

The_Driver
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Good point regarding the emission angle.

Agro calculated the 154cd/mm^2, not me.

Agro
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The_Driver wrote:
Agro wrote:
See http://www.nichia.co.jp/en/product/led_product_data.html?type=%27NVSW219... and http://www.nichia.co.jp/en/product/led_product_data.html?type=%27NVSW219... They state “Luminous Intensity”. Also, you can see a smaller die on the photo.

Thanks! I didn’t notice that before. That’s seems to be quite a nice upgrade! The brightness increase (3.7%) is negligible though.


The front site shows that the LED typically reaches D320 bin, but they list D340 in the datasheet.
EasyB wrote:
The_Driver wrote:
Agro wrote:
See http://www.nichia.co.jp/en/product/led_product_data.html?type=%27NVSW219... and http://www.nichia.co.jp/en/product/led_product_data.html?type=%27NVSW219... They state “Luminous Intensity”. Also, you can see a smaller die on the photo.

Thanks! I didn’t notice that before. That’s seems to be quite a nice upgrade! The brightness increase (3.7%) is negligible though.

I assume that “luminous intensity” is the cd measured directly above the LED. That does not necessarily indicate a higher die luminance. The fact that the 219c and 219d have different proportionalities between the intensity and lumen output means they have different emission patterns, which is supported by their different quoted “directivity” angles in the links above. So the 219d simply has a different shaped dome which directs more light forward.

Also your estimated luminance of 154cd/mm^2 for the 219c d320 seems high. My measurement in the UF1504 puts the effective luminance at 100cd/mm^2 at 5.5A. Assuming 90% lens transmission that is 111cd/mm^2 die luminance. And according to Texas ace’s test of this LED the max output is only 5% greater than the output at 5.5A.


After posting I got a hunch the result was too high. Probably I made a mistake somewhere.
219D won’t be so good then….
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Important notice:

 

I updated the luminance values for all LEDs shown in the test chart in first post, including SYNIOS DMLQ31.SG!

To ensure more realistic values for 'real-life' conditions (flashlight use / secondary optics) I established a new testing method to determine the luminance with a SMO reflector. All upcoming and already existing tests will use this method!

Updating of my other tests will be done in the next hours / days.

 

The SYNIOS are still very nice LEDs with high luminance (at max current 195.0 cd/mm²), but at much lower current as other known LEDs (Black Flat, XP-G2 S4 dd).

My LED tests: Cree SC5 based LEDs (WIP!)  ---  Nichia 319AT 83 CRI - Optisolis (3000/5000 K) - Lumileds Luxeon LXML-PWD9 - Luxeon MZ 5700 K (90 CRI, 3 V) - Luxeon V (CSP) 4000 K 70CRI - Luminus SST-40-W (+ dedomed) - Cree XP-L2 (+ High CRI variant) - XHP35 HI - XHP70.2 - CXA1304 COB - OSRAM OSLON Black Flat HWQP - SYNIOS DMLQ31.SGLE UW Q8WP - unknown 5050 LED ---- finished: JAXMAN M8 (Mini C8) HighCRI Triple

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I’m doing some calculations…
All flat LEDs, emitting light only on the top surface should have the same cd/lm.
I compared several of koef3 tests and found:

Dedomed Luminus SST-40 does 0.324 cd / lm
Cree XHP 35 HI E2 does 0.318 cd / lm
Blackie does 0.294 cd / lm
Cree XHP 35 HI C4 does 0.293 cd / lm

About 10% variance, not bad.

But now let’s do the same calculations for Synios P2720 DMLQ31.SG. Result? 0.213 cd / lm.
Can anyone explain that?

ADDED:
If I get wiki right, the correct result is 1/π cd/lm or 0.318 cd/lm. So all LEDs other than Synios are within 8% of it.

ADDED:
So if this LED delivers as many lumens as it was measured to – it should do about 292 cd/lm².
Your test without reflector has shown 295 cd/mm²…..what’s up?

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I think you might be overestimating the accuracy of optical measurements. koef3 goes to a lot of effort to increase it, but there are practical limits.

Agro
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That’s 33% too low. When all 4 others are within 8% of the expected result.
No, I don’t think this is a measurement error. Or even several, adding up.
I think the emitter doesn’t do what we expect or there’s some error in the method.

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Agro wrote:
That’s 33% too low. When all 4 others are within 8% of the expected result.
No, I don’t think this is a measurement error. Or even several, adding up.
I think the emitter doesn’t do what we expect or there’s some error in the method.

There was some talk awhile back (and I can’t remember if it was confirmed or just speculation) that the XP-G3 had a 3D (not flat) phosphor coating, and that maybe that’s why it doesn’t get good throw performance, even though it has better cd/mm² than older generation emitters.

Anyway, I don’t know if any of that was ever completely figured out. But, if the Synios has a non-flat phosphor coating, that could explain the low cd/lm compared to “standard”.

Reason is not automatic. Those who deny it cannot be conquered by it. Do not count on them. Leave them alone.
-Ayn Rand

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The SYNIOS has some white areas around the die.

There's light shining through or in this area and this has a big impact on the luminance, what the real-world measurements (with reflector) shows. See also my pictures from the test. I don't know that the SYNIOS has a three-dimensional die like the new generation Cree LED platform.

My LED tests: Cree SC5 based LEDs (WIP!)  ---  Nichia 319AT 83 CRI - Optisolis (3000/5000 K) - Lumileds Luxeon LXML-PWD9 - Luxeon MZ 5700 K (90 CRI, 3 V) - Luxeon V (CSP) 4000 K 70CRI - Luminus SST-40-W (+ dedomed) - Cree XP-L2 (+ High CRI variant) - XHP35 HI - XHP70.2 - CXA1304 COB - OSRAM OSLON Black Flat HWQP - SYNIOS DMLQ31.SGLE UW Q8WP - unknown 5050 LED ---- finished: JAXMAN M8 (Mini C8) HighCRI Triple

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The synios die is completely flat, but it is indented so that the white area around it with a “bowl” shape acts as a mini reflector.
So the light is coming from not only the die but also the area around it.

Agro
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koef3 wrote:

The SYNIOS has some white areas around the die.


There’s light shining through or in this area and this has a big impact on the luminance, what the real-world measurements (with reflector) shows. See also my pictures from the test. I don’t know that the SYNIOS has a three-dimensional die like the new generation Cree LED platform.


Enderman wrote:
The synios die is completely flat, but it is indented so that the white area around it with a “bowl” shape acts as a mini reflector.
So the light is coming from not only the die but also the area around it.

This effect means that direct intensity measurements are higher than they should be and should have no impact on measurements with a reflector. They should have marginally negative effect on measurements in an integrating sphere.

What I describe means that the output measurements with the integrating sphere are too high compared to intensity measurements with a reflector.

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Agro wrote:

This effect means that direct intensity measurements are higher than they should be and should have no impact on measurements with a reflector.

This is correct.


Agro wrote:
What I describe means that the output measurements with the integrating sphere are too high compared to intensity measurements with a reflector.

Integrating spheres measure flux output.
This small indent in the surface of the LED does not affect the flux output, it remains the same.
Just because the light is directed forward a bit more does not change the measurement done by an integrating sphere, as the sphere is designed to perfectly diffuse the output and ignore almost all directionality.
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Enderman wrote:
Agro wrote:

This effect means that direct intensity measurements are higher than they should be and should have no impact on measurements with a reflector.

This is correct.


Agro wrote:
What I describe means that the output measurements with the integrating sphere are too high compared to intensity measurements with a reflector.

Integrating spheres measure flux output.
This small indent in the surface of the LED does not affect the flux output, it remains the same.
Just because the light is directed forward a bit more does not change the measurement done by an integrating sphere, as the sphere is designed to perfectly diffuse the output and ignore almost all directionality.

That’s pretty much what I wrote. The small indent absorbs some light, so it reduces flux. But that’s purely marginal.

If the emitter is 0.503 mm² flat Lambertian surface which generates 461.2 lm, it should do so with about 292 cd/mm². Real 292 cd/mm², not abnormal readout caused by incompatibility of measurement technique with construction of this particular LED.
The measured intensity is 195 cd/mm², way lower than prediction.

So either:

  • it is not Lambertian (from the datasheet – it is actually not Lambertian, but extremely close)
  • it is not flat (seems it is)
  • it is not 0.503 mm² (I guess it is)
  • it does not make 461.2 lm
  • it really does about 292 cd/lm² and for some reason the test with reflector can’t show it. As well as results from the few people who tried this LED in flashlights.
  • there is something else?
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Raw data

 

Osram SYNIOS DMLQ31.SG white

 

Amps    lm    Vf
0,05    22    2,76
0,10    40    2,81
0,15    59    2,85
0,20    75    2,89
0,25    93    2,92
0,30    108    2,94
0,35    122    2,97
0,40    136    2,99
0,45    151    3,01
0,50    164    3,03
0,55    179    3,05
0,60    191    3,07
0,65    203    3,09
0,70    216    3,11
0,75    228    3,13
0,80    240    3,14
0,85    251    3,16
0,90    263    3,17
0,95    273    3,19
1,00    283    3,21
1,05    295    3,22
1,10    304    3,24
1,15    315    3,25
1,20    325    3,27
1,25    333    3,28
1,30    342    3,29
1,35    352    3,31
1,40    360    3,32
1,45    368    3,33
1,50    375    3,35
1,55    383    3,36
1,60    390    3,37
1,65    398    3,39
1,70    404    3,40
1,75    411    3,41
1,80    417    3,42
1,85    422    3,44
1,90    428    3,45
1,95    433    3,46
2,00    439    3,47
2,05    442    3,48
2,10    447    3,50
2,15    450    3,51
2,20    454    3,52
2,25    456    3,53
2,30    459    3,55
2,35    460    3,56
2,40    461    3,57
2,45    462    3,58
2,50    461    3,60

 

If you create diagrams / comparisons with this data, I would ask you to publish these charts in this topic and also to specify the source of the data used. Smile

My LED tests: Cree SC5 based LEDs (WIP!)  ---  Nichia 319AT 83 CRI - Optisolis (3000/5000 K) - Lumileds Luxeon LXML-PWD9 - Luxeon MZ 5700 K (90 CRI, 3 V) - Luxeon V (CSP) 4000 K 70CRI - Luminus SST-40-W (+ dedomed) - Cree XP-L2 (+ High CRI variant) - XHP35 HI - XHP70.2 - CXA1304 COB - OSRAM OSLON Black Flat HWQP - SYNIOS DMLQ31.SGLE UW Q8WP - unknown 5050 LED ---- finished: JAXMAN M8 (Mini C8) HighCRI Triple

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