9v blocking oscillator laser supply?

Hey guys, was wondering if the circuit here would be suitable for powering a blue diode from a 9v battery.

quantsuff.com/LED3.htm

I'm no electrical engineer but it seems like this may be usable, and it is pretty efficient as well, probably more so than a 317 based supply.   The current can be adjusted and it is easy to configure it to supply the small amount a diode would need.   The only thing i would be worried about is a spike in the waveform. That should be minimized by the capacitor. it would be neat to have a blue pointer sitting on top of a 9v

There are also some other pages there which have circuits which i'd be interested in trying.  This page has the blocking oscillator set up to step down the voltage, but you can also configure it to step up the voltage from a pair of AA batteries, or a single AA or AAA.
These circuits are very easy to build, and flexible parts wise.  you can use most any small signal npn such as a 2n3904.
Opinions?

To be honest I have no clue whether that would be good for the blueray, but If you wanted to you could get the 7805 circuit to sit on top of a PP3 (9v) battery and it has a lower component count.

Regards rog8811

yeah a 7805 does have a lower parts count by far, but its a linear regulator and you'll never get more than around 50% efficiency running off a 9v and powering a 4.5v diode. I like efficiency if it is obtainable Another thought... these diodes are meant to be pulsed right? Providing the pulse from the coil isn't too much and the cap filters some of it, i wonder if you might be able to drive the laser a bit harder before burning it out.