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Re: LEDs

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  • qbx.photo
    I never had a lamphouse for my Ortholux so I just positioned the LED flashlight in the intermediate ventilation chamber (for lack of a better word) which
    Message 1 of 36 , Mar 28, 2013
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      I never had a lamphouse for my Ortholux so I just positioned the LED flashlight in the intermediate ventilation chamber (for lack of a better word) which contains an adjustable lens (field lens?). I could never see any difference in illumination when adjusting this lens. So maybe I need some additional optics to get better light with my LED. Would you elaborate on this topic? What kind of lens might be needed between the LED and the rest of the optics? would this be a collimating lens? If so, where could I get one?

      --- In Microscope@yahoogroups.com, "Tony" <tony.pattinson@...> wrote:
      > I agree, 3W is plenty for most things. I use them in all my scopes with phase, pol and 100x. Yes, pol does soak up more light and a bit more might be useful. DIC - well, one day!
      > It's necessary to make sure that the led is at the same point as the bulb filament if your'e replacing an existing lamp. If it's a new lamphouse, some optics will probably be necessary. Don't skimp on the diameter of the field lens - the one I used on the M41 lamphouse is ok at about 23mm - just. I like the star configuration leds as they're easy to mount. There seems to be a lack of choice in the uk at the moment, perhaps it will sort itself out soon.
      > Tony
      > Reading UK
      > --- In Microscope@yahoogroups.com, "Randall Buck" <rbuck@> wrote:
      > >
      > >
      > >
      > > It really does depend on the illumination system and how well the LED is
      > > optically aligned within that system. When aligned correctly, 3W should be
      > > plenty except for perhaps crossed polarization , like DIC. 5W should be
      > > sufficient for DIC as well. I have a 10W LED system and that has more than
      > > enough intensity for anything I can possibly imagine. You will need very
      > > good heat sinking for 10W while something quite small will do for 1W and 3W
      > >
      > > Randall
      > >
      > > -----Original Message-----
      > > From: Microscope@yahoogroups.com [mailto:Microscope@yahoogroups.com]On
      > > Behalf Of qbx.photo
      > > Sent: Thursday, March 28, 2013 6:58 AM
      > > To: Microscope@yahoogroups.com
      > > Subject: [Microscope] Re: LEDs
      > >
      > >
      > > You'd do better with 10W LEDs (or stronger) I think. I tried 3w and worked
      > > OK for low power but was a little anemic for 100x and not good at all for
      > > phase contrast.
      > >
      > > --- In Microscope@yahoogroups.com, "billbillt_2000" <2222lab@> wrote:
      > > >
      > > > Hi David,
      > > > It is not necessary to spend that much for a good LED setup..Do a search
      > > on Ebay for 3W LED's and LED drivers..You can rig up your own lighting from
      > > parts for about $20 USD..
      > > > BillT
      > > >
      > > > --- In Microscope@yahoogroups.com, "david barriball" <focusball3@> wrote:
      > > > >
      > > > > Hi,
      > > > > Some of you have used LED bulbs, for your lighting,
      > > > > I can not find the link to them, to what led bulbs you used.
      > > Have found some torches,
      > > http://www.tooled-up.com/product/led-lenser-h14-head-torch-in-gift-box-210-l
      > > umens-size-4-x-aa-batteries/183396/
      > > > > but can not find replacement bulbs.
      > > > > I was wondering if some one else had better luck.
      > > > > Thanks,
      > > > > David
      > > > >
      > > > >
      > > > > [Non-text portions of this message have been removed]
      > > > >
      > > >
      > >
      > >
      > >
      > >
      > > ------------------------------------
      > >
      > > Yahoo! Groups Links
      > >
    • Bob Spez
      Chris, Thanks for the clarification. After doing some searching I realized I wasn t going to find an led replacement for the standard 6v15w projector bulb that
      Message 36 of 36 , Apr 1, 2013
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        Thanks for the clarification. After doing some searching I realized I
        wasn't going to find an led replacement for the standard 6v15w projector
        bulb that is used in the leitz stand.

        So far, the only led light I have used with my microscope is the 13 watt
        dimmable led bulb (800 lumens) in my swing arm desk lamp placed a few
        inches form the standard convex microscope mirror that fits under the

        This light is fine for brightfield, but doesn't generate enough light for
        darkfield using a 40x or 45x objective. So today I purchased a 26 watt led
        narrow beam (25 degrees) dimmable spotlight to fit into my desk lamp. This
        bulb is rated at 1500 lumens and has a warm white light with a color rating
        of 82CRI and 3000K light. The bulb cost a whopping $70, but If it works for
        darkfield and lives up to it's advertised 25,000 hour lifespan it may be
        the last microscope bulb I ever need to buy.

        My other two sources of light, which work equally well for darkfield are a
        fiber optic wand light source, powered by a 21v 150w halogen bulb with a
        built in reflector, and the standard 6v 15W incandescent microscope
        projector lamp bulb. Both put out about 200 lumens, both cost about $10
        each, but are only rated for 200 hours of life.


        On Sun, Mar 31, 2013 at 3:18 PM, Chris Albertson

        > **
        > I think "lumen" is the total amount of light from a bulb. If you add a
        > reflector then the reflected light is added to the light that comes
        > straight from the bulb. So your projector bulb is "brighter" even if it
        > has the same number of lumens. Basically the reflector adds "gain" and
        > has a multiplier effect. This effect can be really large as in car
        > headlights.
        > There are three ways to measure brightness and they all have similar names.
        > (1) the total energy from a light bulb, (2) the amount of light per solid
        > area in a given direction and (2) light per square meter that hits a
        > surface. Confusion happens the names of the units are so similar.
        > Yes, there are LED projector bulbs. Some video projects use LEDs, so look
        > into replacement parts for those projectors
        > I'm still not likley the spectra of LEDs. Try this: In a dark room
        > reflect the LED off a refraction grating (a DVD disc makes a decent
        > grating) and yu can see the "rainbow" image of the LED on the wall. Many
        > of the LEDs I have make bands, not rainbows. Then I confirm by using
        > halogen bult and see the expected broad spectra.
        > A poor-man's spectroscope is not hard to make. use a DVD for a grating and
        > make a 4mm slit and place an SLR camera in back of the slit and watch the
        > camera's light meter as you move the DVD. The LEDs I've seen are so
        > "spiky" you can see it even in this high school level science experiment.
        > Using something this simple you can see the difference between lamps with
        > decent and with poor CRI. But it is not good enough to distinguish more
        > than just good from poor.
        > With LEDs it is a trade off, the most light per watt comes from the
        > tri-color LEDs. From a flat sprectra they need phosphors inside the LED
        > and a filter to attenuate the peaks. This kills the light per watt
        > number. So they compromise and the best or those small surface mount parts
        > that look yellow.
        > On Sun, Mar 31, 2013 at 11:26 AM, Bob Spez <bobspez@...> wrote:
        > > **
        > >
        > >
        > > I've been following this post with some interest but have more questions
        > > than answers. The whole subject of specs on lumens is a tricky one. Specs
        > > on different websites vary widely. The three types of lighting I use with
        > > my Leitz Laborlux black enamel bino scope is the original 6V15W
        > > incandescent projector bulb in the base of the Leitz stand. The second
        > type
        > > of lighting is a 13 Watt LED bulb in a swing arm desk lamp, pointed at a
        > > convex microscope mirror under the condenser. The third type is a fiber
        > > optic wand powered by a 50 watt halogen bulb. I have placed the wand tip
        > > in the same spot as the incandescent projection bulb, under the stand, or
        > > directly under the condenser, with very similar results.
        > > While all three lighting methods give similar results in Brightfield, but
        > > only the incandescent light and the 50 watt halogen fiber optic light
        > > achieve a usable darkfield, and they give similar results in lighting
        > > (though not in color).
        > > Because the 6V15W incandescent bulb is a projection type bulb, it
        > achieves
        > > much more brilliance than the lumens would predict.
        > > It seems like the type of bulb is more important than the lumens it is
        > > rated at. I wonder if they make an LED projection bulb?
        > >
        > > Bob
        > >
        > > [Non-text portions of this message have been removed]
        > >
        > >
        > >
        > --
        > Chris Albertson
        > Redondo Beach, California
        > [Non-text portions of this message have been removed]

        [Non-text portions of this message have been removed]
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