Blu-Ray/445 Diode Test Current Levels for Long Life

[LarryDFW]

After seeing several LPF enthusiasts lose their expensive diodes over the last week,
I think we need to come up with reasonable currents to drive these laser diodes.

With that in mind, I assembled as much data as I could find on various BR diodes.
Sanyo provided a nice chart of pulse LD power.
Sony & Sharp also have pulse power information available on line.

In PM's, Igor & I have discussed the fact that we feel some people are overdriving these LD's.

This is the data that I assembled to give guidelines of operating currents
for reasonably long diode lifetimes (>100 hours).

The chart below starts with:
Pulse Power (from Manufacturer Stated Specs),
Efficiency, Input Power, Voltage (pulse), Input Current(pulse), % Overdrive Power.

I figured backward from Input peak Pulse or Peak power ...,
and in the last column I increased the peak current by 25% to 60% to give estimated operating points.

BR Diode -PulseP-Effic InPow Volt - Input - Overdrive
----------mw---%-----mw--------ma---- Rec.ma - % Over -- - Power
---PHR -- 100 - 24 - - 417 - 5.0 -- 83 --- 104 ma - - 125%- - - 90mw
-4X/S03- 175 - 24 - - 700 - 5.2 - 134 --- 168 ma - - 125% - - 130mw
-SF-210- 200 - 24 - - 800 - 5.3 - 151 --- 189 ma - - 125% - - 175mw
GGW-20L 210 - 24 - - 875 - 5.2 - 168 --- 210 ma - - 125% - - 190mw
---8X --- 250 - 24 -- 1042 - 5.2 - 200 --- 300 ma - - 150% - - 356mw - Tested over 450 hrs.
---8X --- 250 - 24 -- 1042 - 5.2 - 200 --- 348 ma - - 174% - - 455mw - Failed @ 195 hrs.
10X/12X 320 - 25 -- 1280 - 5.3 - 261 --- 420 ma - - 161% - - 600mw - Tested ~ 120 hrs.
S06J-12X 400 - 25 -- 1600 - 5.4 - 296 --- 500 ma - - 165% - - 750mw -
--------------------------------------------------
445 Diode-PulseP-Effic InPow Volt - Input - Overdrive
------------mw---%-----mw--------ma---- Rec.ma - % Over -- - Power
- 445nm - 1000 -25 -- 4000 - 4.5 -1000 -- 1600 ma - - 160% - - 1.75w - 100 hours
445/9mm 1600 -25 -- 5600 - 4.5 -1000 -- 2560 ma - - 160% - - 2.6 w - 100 hours


I also recommend a Schottky diode wired across the power pins with opposite polarity,
to help prevent electrostatic damage.

LarryDFW

 

[Trevor]

Re: Blu-Ray Current Levels for Long Life

Thanks for the info; it'll be handy if I ever procure an 8X or 12X diode on my college student budget.

+1

-Trevor

 

[lasersbee]

Re: Blu-Ray Current Levels for Long Life

Hey Larry..

I'm a bit confused... What LD is this...:thinking:

-PHR ---- 100 - 24 - 417 - 5.0 -- 83 --- 104 ma
-4X ----- 175 - 25 - 700 - 5.1 - 137 --- 172 ma
SF-210-- 200 - 25 -- 800 - 5.2 - 154 --- 192 ma
GGW-20L 210 - 25 -- 840 - 5.2 - 162 --- 202 ma
-8x ----- 250 - 25 - 1000 - 5.2 - 192 --- 240 ma
-12X ---- 320 - 26- 1231 - 5.2 - 237 --- 296 ma
450mw -- 450 - 26- 1731 - 5.2 - 333 --- 416 ma

BTW... not many people are overdriving these LDs...
It seems everyone is over driving these LD for the actual power they were
designed to to be used at...IMO


Jerry

 

[LarryDFW]

Re: Blu-Ray Current Levels for Long Life

Jerry;

That is the Sanyo 450mw diode that was released a few months ago.

Initially, a few people in Japan thought it to be in the BDR-205 .

Actually, I think the Pioneer 12X is a 320 mw diode.
Sharp, Sony & Nichia have 320mw laser diodes in production for 12X.

This one graph released by Sanyo:

LarryDFW

 

[Meatball]

Re: Blu-Ray Current Levels for Long Life

I thought we were purposely over driving our diodes just for the sake of higher outputs..

However, I would care to know when higher than spec is too high considering long life.

 

[Grix]

Re: Blu-Ray Current Levels for Long Life

Not much difference in GGW's and 8x it seems :/

 

[LarryDFW]

Re: Blu-Ray Current Levels for Long Life

However, I would care to know when higher than spec is too high considering long life.

I'm two weeks away from obtaining a 12X like Daves. I would be willing to submit the drive/diode for testing for anyone experienced enough...

I was considering having it sent to either you (Larry) or Dave, but I'll worry about that when I actually get the drive.

That is why I made the chart for safe power levels estimated @ 100 hours of life.

Your 12X would safely operate for a long time at ~310 ma ...

which would give you > 420 mw with top quality optics.

LarryDFW

 

[LarryDFW]

Re: Blu-Ray Current Levels for Long Life

Not much difference in GGW's and 8x it seems :/

There is >40% more power available from the 8X.

That is a sizable increase.

LarryDFW

 

[lasersbee]

Re: Blu-Ray Current Levels for Long Life

Jerry;

That is the Sanyo 450mw diode that was released a few months ago.

Initially, it was thought to be in the BDR-205 .

Actually, I think the Pioneer 12X is a 320 mw diode.
Sharp and Sony both have 320mw laser diodes in production for 12X.

This one graph released by Sanyo:

LarryDFW

Hey Larry..

thanks for enlightening me...
I had not heard of the Sanyo 450 before..

Jerry

 

[Autist]

Re: Blu-Ray Current Levels for Long Life

Good info.

Thanks Larry

 

[LarryDFW]

Re: Blu-Ray Current Levels for Long Life

Dr. Lava just posted a couple of graphs on the Sanyo SF-A210 BR diode.

One of them died @ 275ma of current.

My operating current for long life on that diode is 189 ma.

So the long life operating point is ~70% of the failure poiint for some of these diodes.
That level was 43% higher than the 100 hr. level I calculated.

I will keep track of the testing from Dr. Lava & Igor,
to see if this percentage factor is accurate.

LarryDFW

 

[IgorT]

Re: Blu-Ray Current Levels for Long Life

BTW... not many people are overdriving these LDs...
It seems everyone is over driving these LD for the actual power they were
designed to to be used at...IMO

What did you mean to say with the sentence bolded above?

That everyone is overdriving their diodes BY the power they were made to work at? Like for example if a diode is made to work at 100mW CW, people are driving it to 200mW CW?
I'm not sure i understand it correctly...


But if that's what you meant, i've had good results doing just that - pushing diodes to their rated pulsed power in CW....

For example, a PHR is most likelly a 50-60mW CW diode, i had good results at 110-120mW (@ 125-135mA) if the efficiency was good, above that they would start dying rapidly (in this case, good results mean two or three dead diodes out of 70+).

With 6x's, which are now confirmed to be 100mW CW / 200mW Pulsed diodes (Or in the case of Sharp which might be the GGW, 105mW CW / 210mW Pulsed), i had good results driving them to 180-220mW (@190-200mA) power mostly depending on efficiency - the 210-220mW was only achieved with freaks for example (in this case good results mean only one dead diode out of ~50).

In both cases i am not counting the diodes i killed on purpose of course and "good results" mean "reliable enough for normal pointer use by most people"....


But if this trend was continued in the same fashion, we'd be driving 8x's at 240-270mW (again depending on efficiency)...


One thing i didn't mention above is, that i had the mentioned good results driving those diodes to produce their rated pulsed power after a plastic lens, meaning their actual output power was considerably higher (28-30% higher) and yet they seem reliable enough so far!

If this is taken into account, we'd be getting 307-345mW out of 8x's using short FL/high NA AR coated glass lenses..

But we are setting them to 400-500mW+!


This is what worried me, when i saw 8x's were most likelly rated for 120-125mW CW / 240-250mW Pulsed! That's the reason i proposed the experiment to kill some - to figure out what their rated power really is, or at least to figure out how long they last at the powers we set them to....


We will know more soon, altho i hope not too soon....

thanks for enlightening me...
I had not heard of the Sanyo 450 before..

It's the diode we were hoping and praying to find in 12x writers, cos Sanyo made a big announcement about it a while ago, mentioning 450mW and 12x speed writing on 100Gb capacity BluRay disks...

But problem is, the standard for those disks is not even developed yet, and they will have more layers than the ones available now, which is why higher power is required to write at those layers...


I just don't understand how they will declare that drive. Surelly not 12x as that would cause confusion, besides it will surelly have higher SL and DL writing speeds... Strangelly, the diode is depicted to the right of the 300mW one at the 12x speed height in their charts (just like the 900mW :thinking...

It already caused enough confusion (and dissapointment) to us unintended users of their products...

 

[XGX]

Re: Blu-Ray Current Levels for Long Life

Great chart thank you.
Is there any formula to calculate it? Or does it depend on how [un]lucky you are and is only based on statistics?
Anyone knows how much a PHR set to 120 mA would last approximately?

 

[ElektroFreak]

Re: Blu-Ray Current Levels for Long Life

Are these results based on actual long-term lifetime tests? If not, then this is just all conjecture which is no better than we've had all along..

People keep assuming that there is some sort of finite, exactly predictable behaviors to be expected from an overdriven diode. The fact of the matter is that if a diode (or ANY electronic component for that matter) is run over it's RATED power, it's behavior becomes unpredictable. This increases as you exceed the ratings further. Since we don't have datasheets for any of these blu-rays, we have no clue about their ratings. The ONLY way to establish lifetime figures for these diodes is to run several groups of each at different currents for each group and run them all until they die, averaging the lifetimes of each group at the end. A very expensive proposition, but a similar system is how the manufacturers establish lifetime figures. That is the ONLY reliable way to do this. Anything else is just speculation based on educated guesses.

When you're using the diodes in pointers, where they have limited burn times, lifetime isn't even all that important. Most people will be lucky to put 1000 hours on the diode in their lifetime. With other applications, like laser shows or scientific usage the hours rack up quickly and so being able to accurately state a good lifetime figure at a given current is of paramount importance, and speculation won't cut it.

My own personal experimentation involved several PHR diodes which I ran to death. The results of my findings indicate 90mA as the best current. All of my diodes that I ran at 90mA for this experiment survived to 4000+ hours. Once died at 4600, the rest still survive because I ended the experiment. 4000 hours is sufficient for my needs.

Out of the diodes that I tested at 100mA, 2 out of 3 had died shortly after 1000 hours, the third made ~2200 hours.

 

[LarryDFW]

Re: Blu-Ray Current Levels for Long Life

ElektroFreak;

We have little actual data on these laser diodes.

The manufacturers (Sharp, Sony, Sanyo, etc.) have published press releases with maximum pulse power levels.

We know that the optical mirrors can operate at these 50% duty-cycle pulse levels for 1000 hours
(Sanyo & Nichia PR charts).

These "Maximum Rated Pulse Power Levels" are what I used to predict a "safe operating current" in the chart above.

Edit: Nichia has released pulse operating levels of 260ma for their 12X 320 mw BR diode.

It is a calculated guess, but I think there is enough data behind it to make it reasonable.
I did have to make some assumptions on operating voltages, but I think they are close.

Now, with Dr. Lava and Igor doing some actual destructive testing,
we can get even closer to operating current levels.

LarryDFW

P.S. Thanks for posting the long term testing info on the PHR diodes.
104 ma was the recommended level in the chart above,
and you got several hundred hours @ 100ma.
Long Term PHR life looks fairly close

 

[ElektroFreak]

Re: Blu-Ray Current Levels for Long Life

^I would agree that your method should produce reasonable results for use in pointers..