Page 1 of 2 12 LastLast
Results 1 to 10 of 11

Thread: jelly beaning blue

  1. #1
    Join Date
    Jun 2008
    Location
    chesterfield uk
    Posts
    466

    Default jelly beaning blue

    hi

    i have a f2000 laser projector and recently i think its started jelly beaning on the blue diode. the blue when looking at the wall looks a bit like static off a telly. to be honest i think when its on a tunnel effect it looks damn good and im not that bothered about it.
    im just wondering if this means my bluey might pack in soon????

    what actually is this jelly beaning?
    is there any way of stopping it? (not that i want to)

    and i think i read in another thread that someone else was having this and they thought it looked good and they asked if it was possible to make this happen then turn it normal again? i was wondering this too?

    cheers ollie
    2 x 10w full colour laser systems
    2 x 4w full colour laser systems
    2 x 3w full colour laser systems
    1 450mw pinkem rgb 30k scanner
    2 x 1 watt green laser
    4 x 1 watt blue 445nm laser systems
    3 watt rgb .

  2. #2
    Join Date
    Jan 2007
    Location
    Sheepsville, Wales, UK
    Posts
    3,406

    Default

    Ollie

    Jelly beaning is basically noise in the beam If you were to see an oscilloscope representation of the output it would resemble white noise. Its caused by instability in the laser usually (but not exclusively) due to temperature. The problem with blue is to get the best power you need to be very specific with temp of internal parts. This is ok in CW mode as its predicatable but when you start modulating the stability goes out the window and the Tecs cant keep up with whats going on and can never know whats coming next. Part of the problem I believe is due to most modules having single ended tec control - which means the tec can only heat OR cool the internal parts not both. To get very accurate and stable temp even when modulationg takes a few tricks in the driver but the fundamental thing would be a tec control that can heat AND cool the xtals/diode

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
    Laserists do it by the nanometre.

    Stanwax Laser is a Corporate Member of Ilda

    Stanwax Laser main distributor of First Contact in UK - like us on Facebook http://www.facebook.com/FirstContactPolymerCleaner
    www.photoniccleaning.co.uk

  3. #3
    Join Date
    Jul 2008
    Location
    Marysville, WA
    Posts
    855

    Default

    What you're describing almost sounds more like a dirty collimating optic or even IR filter (whatever the final optic is on your laser module). Maybe I'm just not fully understanding what you're describing, though... do you have a picture?

    As far as I understand 'jelly beaning', it's where the laser cannot keep up with the modulation signal that is coming in. DPSS lasers especially struggle with this. As you know, when you click a laser on it isn't instant. There is a ramp up/down time. If you are trying to modulate faster than the laser can rise and fall in power, you end up getting the 'jelly bean' effect where the line of the pattern being drawn looks like a bunch of jelly beans stacked together rather than a solid line.

    EDIT: Ohhh... now that I re-read and 'thought' a bit more, I think I get what you're saying. Lets say you're projecting a blue circle on the wall, are there 'irregularities' or very tiny 'breaks' in the line creating circle causing it to look static-y?
    Last edited by GooeyGus; 12-03-2008 at 17:15.

  4. #4
    Join Date
    Jan 2006
    Location
    Charleston, SC
    Posts
    2,147,489,446

    Smile

    Quote Originally Posted by GooeyGus View Post
    As far as I understand 'jelly beaning', it's where the laser cannot keep up with the modulation signal that is coming in. DPSS lasers especially struggle with this.
    This "blanking-induced power loss" is related to jellybeaning, as they are both normally caused by temperature instabilities in the lasing caivty. I admit that I've used the term jellybeaning to refer to blanking induced power loss before.

    However, I do believe that Bill Benner originally coined the term to refer to the noise that is present in the continuous power beam when it is scanned. This looks like "static" (or little jellybeans stacked end-to-end), and is common to many DPSS designs.

    I think since then the term has evolved to refer to any number of power or beam quality issues related to DPSS lasers. Just my opinion though...

    Adam

  5. #5
    Join Date
    Dec 2006
    Location
    Netherlands
    Posts
    983

    Default

    edit: see 2 posts down.

    Does it look like that?
    If it does, it is quite normal unfortunately. This is a 473 CNI that I bought about 20 months ago. I don't mind it too much, the laser is outputting twice its rated powers so that makes up for it.
    Last edited by Zoof; 12-04-2008 at 11:32.

  6. #6
    Join Date
    Jun 2008
    Location
    chesterfield uk
    Posts
    466

    Default RE

    like what mate?
    2 x 10w full colour laser systems
    2 x 4w full colour laser systems
    2 x 3w full colour laser systems
    1 450mw pinkem rgb 30k scanner
    2 x 1 watt green laser
    4 x 1 watt blue 445nm laser systems
    3 watt rgb .

  7. #7
    Join Date
    Dec 2006
    Location
    Netherlands
    Posts
    983

    Default

    uh,like this: ..............
    Attached Thumbnails Attached Thumbnails IMG_3508.jpg  


  8. #8
    Join Date
    Jul 2008
    Location
    Rotterdam, Netherlands
    Posts
    789

    Default

    Quote Originally Posted by Zoof View Post
    uh,like this: ..............
    Looks more like NOISE... :-)

  9. #9
    Join Date
    Jul 2008
    Location
    Maryland
    Posts
    1,691

    Default

    clean your friken lense
    Quis custodiet ipsos custodies?
    Solid State Builders Group

  10. #10
    Join Date
    Jun 2008
    Location
    chesterfield uk
    Posts
    466

    Default sort of

    a little but more perfect. its like this -------------------------.

    ollie
    2 x 10w full colour laser systems
    2 x 4w full colour laser systems
    2 x 3w full colour laser systems
    1 450mw pinkem rgb 30k scanner
    2 x 1 watt green laser
    4 x 1 watt blue 445nm laser systems
    3 watt rgb .

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •