Possible 8X Sled from HighTechDealz

[IgorT]

Looks to me like it goes back to the OEIC...the same end spot that the Blu-ray has.

Yea, it doesn't take it back to the diode, but to something above the diode, which is not drawn.

Must be a sensor there...

 

[Meatball]

Igor, I like the way you think.. Like in post #58, I've wondered about the different ways to quantify a diodes' efficiency. Yes, there is the typical slope of the mA/mW plot... and thats worked well until now. So do you suppose that we ought to start moving away from this?

Say if we decided to measure Raw Power Out (no lens) / Power Draw...

Raw (no lens) Optical Power Output DIVIDED by Measured current*measured voltage across diode...

for example...

450mw (no lens) from 350mA at 5.7 volts.... yields .450W/1.995W = 22.56% efficiency from the diode..

I think we ought to make this universal to compare diodes to one another, espeically since it eliminates the lens factor, which I think has a greater effect on our outputs than we usually think since the output wavelengths of these diodes can actually vary by + or - 10nm.

Just an idea... but I would just like to present it to you as a helpful way to compare any two "identical" diodes.

I hope it can help.

Tyler

 

[LarryDFW]

Thanks!

Now are there any reasonably detailed PIV plots of any of these diodes, i could look at? I am used to seeing only the slope-efficiency plots of 8x's, but no Voltage data in them..

The slope efficiency plots are good for comparing diodes of the same type, but for a detailed analysis of a single diode, a plot should show the voltage data as well...

Here's your voltage plot:
... power testing on my first 8X...
with the new brass machined Hi-Power lens assembly.

Here is some of the preliminary data:

I (ma) Power(mw) Voltage
40 . . . . . 9 . . . . . 3.7
50 . . . . . 14 . . . . 3.8
60 . . . . . 28 . . . . 3.9
70 . . . . . 42 . . . . 4.0
80 . . . . . 60 . . . . 4.15
90 . . . . . 75 . . . . 4.3
100 . . . . 85 . . . . 4.4
110 . . . . 103 . . . . 4.5
120 . . . . 117 . . . . 4.6
140 . . . . 148 . . . . 4.7
170 . . . . 194 . . . . 4.9
190 . . . . 212 . . . . 5.0
200 . . . . 233 . . . . 5.05
220 . . . . 258 . . . . 5.1
240 . . . . 286 . . . . 5.2
260 . . . . 318 . . . . 5.3
280 . . . . 344 . . . . 5.4
300 . . . . 376 . . . . 5.45
330 . . . . 410 . . . . 5.5
350 . . . . 441 . . . . 5.6 > > 1.96 Watts total - ~0.5 Watt Light = 1.46 Watts Heat

I liked the relatively low voltage on this diode. This means it is more efficient & should make it easier to drive.

Power was fairly good. About 22.5% efficiency @ full power with lens.

I calibrated my Scientech LPM before the test, so it should be fairly accurate.

The diode came out of a Buffalo 8X, which is actually a Panasonic SW-5584 drive obtained by Misterwilling.

LarryDFW

 

[Meatball]

Hey Larry, does your LPM work without a lens on the diode? Are you able to put the diode right up to the sensor? I would be interested in seeing THAT output..

theoretically, if your lens truly and consistently passes 95% of 405, then the output without a lens should be around ~464mw..

This would result in a diode with 23.7% efficiency..

 

[LarryDFW]

Milos ran diode tests with my lens & without it.

He got 96.5% with the Hi-Power lens.

My Scientech will measure without a lens, but I have to take the barrel off.

LarryDFW

 

[IgorT]

Igor, I like the way you think.. Like in post #58, I've wondered about the different ways to quantify a diodes' efficiency. Yes, there is the typical slope of the mA/mW plot... and thats worked well until now. So do you suppose that we ought to start moving away from this?

Well, when i test a new diode, i always make a full P/I/V plot on my "Diode Analyzer" - a device, which replaces two DMMs, a regular driver where the current normally isn't linearly adjustable, and a huge mess of wires and aligator clips, that would otherwise cover the table, with a handheld sized box with a driver with two pots, where one sets the max current and the other then adjusts from 0 to 100% of the max setting in it's full swineg completelly linearly..



I always also note down the Vf's, even if only testing the same diode type.... Very often a diode of the same type appears less efficient until you look at the Vf data. Then you realize it has a lot lower Vf, and is actually just as efficient at a higher current as another at a lower current.

Altho this doesn't happen often, i still need to test if it means anything when it does.... For now i put such actual as well as "pretend-" low efficiency diodes aside for later more detailed testing and comparison, to see if the lower Vf's can make a difference in how much current a diode of the same type can survive.

I'm wondering if such a diode can be set to the same electrical power and survive (= higher current times lower voltage = same electrical power in)...

Or even if the diode's low Vf and lower apparent efficiency could mean, that it's actually a much tougher diode that can be set to a higher power - a freak result of the unreliable manufacturing process?




Anyway, the full P/I/V plot nicelly describes any diode being tested..

When i compare several diodes of the same type, i often just leave the voltage data out of it, since it's usually less important, as it doesn't vary much between them except in rare cases (such as i described above).



But if you have the full data collected, it's easy to make a fourth row in Excel, where you simply multiply the current and voltage, and plot the result against the output power...

This COULD turn out to be even more important, when comparing diodes of a different type!


Like i said, the Vf does have a meaning with these diodes. It is usually specified to be between 5-5.5 or 5.5-6V in the datasheets.

For an unknown (no datasheet) diode the "normal" range should be between 5-6V, and when you start crossing 6V, it COULD mean you are going WAY outside the safe limits for that (or even any) diode...


Theoretically a diode could also just have a much higher Vf for some strange reason. But it would be the first so far.. Because every time i handled a higher power diode, it's Vf was always back within these limits unless it was being overdriven very hard!

I think if the Vf doesn't go far above 5.5V, it COULD mean the diode is still not set to a too high current...



But regardless of what it means, the Vf MATTERS for actual diode efficiency!

So when we compare diodes of a different type, the Po/Pe plots could be even more meaningful, yes....



In any case, i'll keep collecting the entire data for all diodes, even if i have to do it in lower resolution (when testing huge batches of GGWs), and then i can always multiply two rows in Excel if i want to, before making a plot out of the data...


I think the best way to compare two different diode types would be to make BOTH a slope efficiency comparison plot AND a Po/Pe comparison plot. More data = good... :yh:

Say if we decided to measure Raw Power Out (no lens) / Power Draw...

Raw (no lens) Optical Power Output DIVIDED by Measured current*measured voltage across diode...
for example...
450mw (no lens) from 350mA at 5.7 volts.... yields .450W/1.995W = 22.56% efficiency from the diode..

Yes, that IS exactly how efficiency should be correctly calculated....

I think we ought to make this universal to compare diodes to one another, espeically since it eliminates the lens factor, which I think has a greater effect on our outputs than we usually think since the output wavelengths of these diodes can actually vary by + or - 10nm.

Just an idea... but I would just like to present it to you as a helpful way to compare any two "identical" diodes.

That's exactly what i was proposing, when talking about the Vf's of the BDR-203 diodes, compared to the Pioneer diodes, yes...

Why do you think i keep asking for the voltage data?

If everyone collected the full PIV data, we can still make the Po/Pe plots for comparison later...



Otherwise, when it comes to the raw power, what i do is, i use a special "Nichia Lens", which has a very short FL and high NA and a wavelength specific coating centered at 408nm - all it's specs are designed per specifications of Nichia for 405nm diodes... The coating looks red, much more so than 660nm coatings look blue...


This lens has extremelly low losses at 405nm, the wavelength differences between diodes have no effect on the throughput, and it's high NA eliminates differences in throughput due to the aspect-ratio of the diode output...


When i said before, that the 28% increase was a guesstimate, i was mainly talking about the fact that diodes vary in wavelength A LOT (during pre-testing i sort them by wavelength as well), because a small wavelength difference has a HUGE impact on the losses in acrylics!

So much in fact, that the shortest wavelengths i found had an increase of as much as 43% when glass was used instead, just because that much more was being lost in plastics! And i've seen even shorter wavelengths since! (i once made an ultra short wl. 6x on request, and it turned out to be under 400nm! And i have an even shorter Wl PHR!)


But normally, even broadband coated lenses elliminate wavelength and aspect-ratio related throughput differences, if they have a high enough NA, and besides, for comparison, you don't really need to know the EXACT raw power...

The only thing that is important for a proper comparison is, that you don't have different losses with one diode than with another, and that you take the entire electrical power into account, and not just the current....


So a lens like the short FL / high NA / broadband AR lenses, already available on the forum are good enough for this purpose. No need to cut modules short just to measure raw power!


But using acrylics is definitelly no better a basis for comparison, than using slope efficiency data alone... In both cases you are ignoring a part that could make a big difference, if taken into account.


For example, i have seen diodes of ULTRA-short wavelengths display freak-like efficiencies after acrylics. Only after i realized how high their losses must be, did i realize how high their efficiency actually is!


A short wavelength diode with the same power after a plastic lens in reality has a MUCH higher efficiency! A short wl. diode should display a much lower apparent efficiency after plastics, if it's actual efficiency was the same.


Same goes for a lower Vf diode. Even if it needs more current to reach the same power, it's actual efficiency COULD be higher or same, not lower! The only way to figure it out for sure is to test with AR coated high NA glass and to make a Po/Pe plot..

 

[Arenared]

Preciselly!

This is why i think it is likelly the real deal! We know that Kendall's mystery sled has the Long Closed Can red inside.

I would very much like to compare the optical train drawn here and to see if it is also exactly the same. :yh:


In my oppinion, you made a great find with that page!



Otherwise, i really find it hard to believe, that no one gutted the Pioneer drive yet!

What's the other 8x drive that was used by members of this forum then?

right now im using an LG8x @ 360ma with a flexv4 , it burns really hard. I dont have a meter to say precisely what the output is. i also have a Pioneer 8x which i will be building as soon as i get my drivers from dr lava. but we shall see how it fares against the LG in side by side burning, both on glass high power lenses.

 

[IgorT]

You have an LG8x? Wow... Any pics of the diode?

Really a shame, that you don't have a meter...
You think it would be possible to measure the voltage across the diode at 360mA tho?


As for the Pioneer 8x, did it come from a drive or from these sleds?
And if it came from a drive, could you take some photos perhaps? Describe the diode? Does it have markings? Barcode or numbers lazored into the can?

What about the LG diode, what kind of markings did it have?

 

[daguin]

We need to change the "labeling" used herein. There are at least two different diodes from Pioneer being talked about here.

I have tested the diode (self harvested) out of a Pioneer BDR-203BK and now this sled which is supposed to be from the BRD-S03 drive

My results for the BK sled are here:

http://laserpointerforums.com/f51/pioneer-8x-blu-ray-bdr-203-a-36790.html

However, just the limited voltage readings for the BK are:

100mA = 4.8V
200mA = 5.5V
300mA = 6.0V
350mA = 6.2V

The test was done with the Rkcstr and 12V from my 2A bench PSU.

Peace,
dave

 

[FrancoRob]

Updated - 2009/08/16

NOTE: HAVING SEEN HOW MEMBERS ARE INTERESTED IN THESE DIODES, AND THE QUANTITY OF DATA INVOLVED, I HAVE MOVED ALL 8x BR GRAPHS AND DATASHEET IN THE NEW TOPIC: "Blu-Ray & Violet Lasers - 8x BR DIODES". SO ALL UPGRADES WILL BE APPLIED IN THE NEW DEDICATED THREADS.
Justs to see how an efficiency curve can be, I have applied the formula used by Meatball to the LarryDFW data. My Excel skill is just the minimum, so I have not been able to make a common graph showing both the Power Output and the Efficiency in %.
So, here the result, with the P.O., the Eff% and the Pi/Po shown in three different diagrams:

To valuate this efficiency, it is necessary to remember that the Power Output values have been obtained with the Larry no-spring special lens.

 

[HIMNL9]

Uhm ..... wondering about put one of these diodes on a TEC stabilized heatsink and do a "to the destruction" test with 30 seconds cycles, for see what is the maximum current / power possible ..... :eg: op:

 

[Meatball]

Wow FrancoRob! Its nice to see these two plotted side by side!

To me, its very clear that these two graphs are showing relevancy to one another.

On the red line beneath, you can see a small peak in efficiency, which in-turn, reveals a small slope increase in the mW/mA graph. This means, that our usual way of observing diode efficiency (apparent efficiency) is still lining up with the Po/Pi (actual efficiency) graph.

Just before the blue line, you can see a decrease in efficiency. But since the efficiency is still positive, the mW/mA graph shows a continued positive slope, a slowed increase but still positive.

But the orange circle... I haven't a clue whats happening there. Its happening around 100mA which is well above the threshold current, so you might think that efficiency what only be steadily increasing by this point. I wonder whats happening here..

FrancoRob, Is it possible for you to make a plot of the integral of the second graph? I believe it would simply be a Po/Pi graph. We have its derivative, but I think that if we can get its integral plotted, we may have a better idea of how to relate it to our typical mW/mA graph. If we can tie it all together properly, we should hopefully just end up with a simple calculus formula that could help us directly find a true efficiency (Po/Pi) from our simpler apparent efficiency (mW/mA) graph. Then we would have have to graph absolutely everything all the time. We could then just stick with our typical plots instead.

 

[IgorT]

That's what i intend to do with the sample from Kendall, however not with a TEC. But it will be cycled to death.

A TEC can be used to force the diode to have a higher efficiency. But the higher optical flux will also cause more "pressure" on the die.

Mainly i want to find out a power where they can survive like 150h+...




Franco: That's an efficiency plot, yes. They are very interesting, altho what i meant was a Po vs. Pe plot to compare different diodes with, instead of the usual Po vs. I plots that we normally use... Or rather in addition to them.... Po vs Pe plots, while not directly showing the efficiency would show which diode is more efficient better than the mW per mA plots.

An efficiency plot like the one you made is very good for detecting kinks, altho the kinks in this one are more likelly just measurement errors. Towards the higher currents the efficiency slowly drops off, but that's most likelly just from more heat being developed, since only passive cooling is used...


For perfect P/I/V plotting one would really need a TEC setup with a constant temperature driver. Not for force-cooling, but for preventing temperature from drifting.. That's actually what i'm working on with Jayrob's help.. :yh:

 

[IgorT]

Dave: I thought i heard of a Pioneer 8x being used before... That's why i was confused...

But clearly it's a different diode. I read about your findings, you mentioned "simpler optics" i believe?

Simpler optics COULD mean a lower power diode.. Which would also explain the Vf being so high as you cross 300mA...

There are two ways to make a faster disk writer:
- Same optics / Higher power diode
- Same power diode / More efficient optics

Of course it's hard or impossible to compare the efficiency of sled optics by looking at them, but the above was my argument, for why the 4x and 6x sled can not possibly use the same power diode, since they use identical sleds and optics...


But in theory, two different drive manufacturers could chose two different diode power ratings, and then each design a sufficiently efficient optical train for those two different diodes to write at the same speeds...

Or a certain manufacturer could theoretically first make an 8x drive using a higher power diode, and then later a slightly lower power diode, but with more efficient sled optics, as they advance their optical designs further (fact is, they do keep changing them, or they would only be changing the diode power rating and always use the same optics)..



Then there is another thing to consider...
Do these sleds use the beam "circulariser" cubes, like the 4x's and 6x's?
Also, what is their beam profile like in comparison to one another? Is one flatter than another?



We use the entire power of a diode (especially with high NA lenses), while a sled manufacturer needs a perfectly round beam for a sharp enough focus. They use the "circulariser" cubes to correct the aspect ratio a little, and then "trim the edges" away with several LCD windows in the path, until they are left with nothing but a perfectly round cone of light coming out of the focusing lens.


The focus has to be sharp, especially with disks with a higher density of information storage (like BluRays)...

A rounder beam diode may be used much more efficiently, and require a lower rated power for a certain disk writing speed, while flatter beam diodes require more beam correction, resulting in higher losses, requiring a higher power rating of the diode...


In this case, a flatter beam diode used in the same speed drive COULD give us more power, than diodes with a better aspect ratio, simply because it would be used far less efficiently....


We prefer rounder beams, but mostly we just care about the total power coming out of a diode, and these diodes can have a lot of their power in the fast axis... That's why flatter beam diodes could end up giving us more power.


I think that's one of the reasons why PHRs are rated so high, while only being used in readers... That and the fact that they use a joint beam-path with the Red and IR, requiring broadband coatings and more combiner optics, resulting in more losses.

Writers use dedicated beam paths and wavelength specific coatings to make the most of a diode's power on the other hand.

 

[FrancoRob]

Meatball:
I have updated the plots with the add up of the Pi/Po diagram.

 

[daguin]

Dave: . . . I read about your findings, you mentioned "simpler optics" i believe?

Simpler optics COULD mean a lower power diode.. Which would also explain the Vf being so high as you cross 300mA...

I don't remember the "simpler optics" comment. Here it is:

It doesn't have to make the u-turn that the S03 does.

Peace,
dave