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D Yuniskis D Yuniskis is offline
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Default Practical LED illumination issues

GregS wrote:
In article , D Yuniskis wrote:
Hi,

Motivated by the CFL thread, I'm looking for info on
fabricating "light panels" for use under kitchen
cabinets. Typically, low profile fluorescent fixtures
are used in these places. But, they often require
the addition of a molding to completely conceal their
presence. This reduces the working distance between
the countertop (which is fixed by the height of the
"base cabinets") and the underside of the "wall
cabinets" (which is fixed by the height of the ceiling!).

One amusing approach considered was to use the backlight
assemblies out of LCD monitors (i.e., remove the active
display and just use the CCFL's with the mechanical
diffuser). While this would be an amusing approach, I
don't think it practical. : (I'm not keen on having
all that high tension wiring around *water*!)

The next approach was a panel made of (white) LEDs
possibly embedded in some white/opaque plastic to
produce a luminous surface. This would probably lose a
fair bit of light due to the diffuser.

Another approach was to just tightly pack LEDs in a
linear array (similar to a fluorescent tube in mechanical
design) and attach *that* to the cabinet underside.

But, I am unsure of how realistic such an approach would
be. The total light available would be an issue as would
the power requirements and the heat dissipation. Cost,
of course, is also an issue.

Aside from empirical testing, I'm at a loss as to how to
evaluate this approach without investing lots of time
and/or money.

Thanks!


I used some led's and put the sink side inside a little circular
plastic dish. It actually some kind of laboratory specimin container.


Petri dish, no doubt ?

Its not perfect as I had to put some black tape around it so


I think if the lamps were in a linear array -- so that the entire
"light" was only 1/4" thick, 3/8" tall and as wide as the width
of the cabinet -- then you could tuck it up under the front edge of the
cabinet angled rearward and avoid much of the visibility issue
(unless you are talking about cabinets over a penninsula whic
could be visible from either front or back)

you don't see the light. I am using a moderate level of light, and they are
always on. I intend on hooking them up to battery backup,
along with the under counter bathroom lights I installed.
With the Cree warm lights, i get plenty of brightness using only 50 ma.
I had to use 100 ma. with some Luxeons. I am only using one lamp per couple feet of


"per couple of *feet*"? Is the amount of light you get
suitable as a nightlight? Or, enough to *augment* the normal
work light available in the kitchen (I want the added light to
be able to see things that are under the cabinets which are
invariably in shadow -- from the cabinets themselves *and*
your own body as you stand between the worksurface and the
overhead source of regular room illumination)

coverage. I also instaled an over the counter one in the bathroom, which
lights up the ceiling.


But this seems like it would be more of a "nightlight" role?