Converting a 200W discharge lamp video projector to LED

[N_Cook]

Assuming over-riding the opto couplers to falsely confirm to the system
micro that the arc is struck and the lamp is lit (maybe requiring a
delay) firstly, with the lamp ps disconnected.
Then I intend in the first instance to buy 5x 1.2W white LEDs, 3500K, 20
degree, for proof of concept. Assuming that sort of works then get
perhaps 10 more, going down to 2700K or 3000K or perhaps (unlikely)
4000K and lenses to colimate to 2 degrees. Set inside a reversed conical
silvered glass of an ex-lamp to direct spillover light into the
colourwheel/light tunnel aperture.
The intended LEDs are 11x10mm footprint so can be mounted quite close to
the colourwheel(for 5 anyway) on a spherical back mount. I may as well
retain the original fans, perhapps knocked back a bit for less noise
intrusion later on.

When coming to scaling up I originally was thinking of using a sectored
curvi-linear silvered reflector from PIR units (with faned air cooling)
but have since come across 2 degree lens converters for these LEDs so
may as well go with them and shine directly from a larger spherical
backing mount, directly to the colourwheel aperture.

I'd be interested in any suggestions or comments other than of the I
would not bother type of replies. Anyone happen to know what the light
wastage proportion is of a non-ideal paraboloid reflector and non-point
source discharge lamp is? I'm aware proper LED projectors have active
drives to RGB LEDs and not colour wheels but there are a lot of
ink-jet-printer-syndrome surplus HD video projectors around with too
expensive short-arc lamp costs to replace

Some bods been here before with converting a couple of types of
discharge lamp converters
http://www.blue-room.org.uk/index.php?showtopic=54833
http://www.blue-room.org.uk/index.php?showtopic=51365&st=0&p=426504&#entry426504

If anyone is interested, my exploration of inside a standard domestic
GU10 LED lamp (to see if they were all in series or mixed series/parallel)
240V,2W.
Breaking in:- hold the bulb in a glove and heat the dome cover with
"low" temp hot air and prize off with a needle. With old soldering iron
destroy the epoxy join between the , not obvious as silvered, pcb to the
lamp housing. The slight greeen colouration is due to the reflection of
the green dye of the pcb which is not glass fibre reinforced it seems,
maybe epoxy substrate only. Prize the pcb away.
No glass breakage at any stage.
Overlay of this one marked JH-GU10-20
HV ac side 1M//0.33uF 400V dropper and 1/4W resistor size
fuse/inductor/fuseable resistor? pink colour with red black brown, or
reverse order, colour bands, about 0.4R to small SMD MB6S bridge
rectifier.
LV quasi-DC side SMD 510R dropper to 20 LEDs in series.
White ceramic cap is cemented to the glass of the lamp.
Bench ps 50V across LED string and 510R all LEDs just lit
54V and 0.5V over 510R and about 2.6V over each LED some sort of low
level brightness.
With 75% mains (240V that is) 6.5V DVM dc over 510R
or 5.5V DVM ac over 510R
100% mains 9.1V "DC" or 7.2V as "AC" reading over the 510R

[William Sommerwerck]

Have you calculated whether you can cram enough LEDs into that space to get
the same brightness level as the discharge lamp? Or are you expecting to learn
from the test?

I'd like to point out that is no such thing as -- nor can there be -- a white
LED. LEDs are necessarily limited to a narrow band of wavelengths. * All (???)
white LEDs are (I assume) a blue LED with a yellow-fluorescing phosphor. **

This /looks/ white to the eye, but the red and green wavelengths needed for
color reproduction aren't present.

Unless your white LEDs contain red, green, and blue LEDs, I don't think this
is going to work.

* This is actually a good thing if one is trying to match a specific color
space, and you can manufacture LEDs whose wavelengths correspond to the three
primaries.

** I'm thinking of indicator lights and such. Lamps to replace incandescent
lighting would necessarily have to put out red and green, or colors wouldn't
look right.

[N_Cook]

Its not possible to do any calculation as to brightness because it is
impossible to find the true loss of light from a conventional
distributed ie not point source discharge lamp source and non ideal
reflector, I would guess that 2/3 of the rated light does not get into
the apaature and then how to calculat the proportion that is at such an
angle to the light tunnel to the active chip and multiple reflections
that little of that gets to where it is wanted, axially along the 2
inches or so of narrow diameter light pipe .

As for colour rendition it is unlikely to be any worse than the current
situation of having to place a rose-pink filter over the projector lens
to get some red into the image as the lamp must be too far into the blue
end of the spectrum tio be compensated for in the setable timing of the
colourwheel.

So in both cases very much a suck it and see, seat-of-ones pants
situation, but worth a go, if you've seen the price of these supposed
replacement discharge lamps

[N_Cook]

On 27/09/2013 14:46, William Sommerwerck wrote:

I've had another look at the product data and the 2 degree lenses are 4
degree , in normal terminology

I don't know what chromaticity means but for the 3500 deg K version a Cx
of about .4 and Cy of about .39
A bit more graphic the spectrum is continuous and smooth "bell curve"
peak shifted 40nm from 550nm of the standard eye response curve to 590nm
and the 50% points broader apart at 150nm compared to 100nm of the eye
and a 50% down peak at 460nm which I suppose is the potential bugbear
for such a lamp conversion

[William Sommerwerck]

"N_Cook" wrote in message news:l245i3$n48$1...@dont-email.me...

I don't know what chromaticity means but for the 3500 deg K version a Cx
of about .4 and Cy of about .39
A bit more graphic the spectrum is continuous and smooth "bell curve"
peak shifted 40nm from 550nm of the standard eye response curve to 590nm
and the 50% points broader apart at 150nm compared to 100nm of the eye
and a 50% down peak at 460nm which I suppose is the potential bugbear
for such a lamp conversion

Could you send me the data sheet, or its URL? I'd like to take a look.

[N_Cook]

LEDs, I did not find a uk/us URL
http://www.promelec.ru/pdf/LCWW51M.pdf
lenses
http://www.farnell.com/datasheets/607410.pdf

[Jeff Liebermann]

On Fri, 27 Sep 2013 14:34:59 +0100, N_Cook <div...@tcp.co.uk> wrote:

>Then I intend in the first instance to buy 5x 1.2W white LEDs, 3500K, 20

>degree, for proof of concept. (...)

I've done this with marginal sucess. The problem is focus. The
original light has all the light coming from roughly a single point.
An array of 5 LED's will distribute the light over a much larger area.
It will work well with light from the central LED using the original
reflector, but the outer LED's will be wasted and splattered all over
the room.

You don't really need the original reflector if the light source has
its own forward facing reflector. Try cramming an MR16 bulb in place
of the projector bulb and reflector. The smaller size MR16 lamps
might fit.

More:
<http://www.instructables.com/answers/Change-a-projector-lamp-to-LED-/>

--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[William Sommerwerck]

>> Could you send me the data sheet, or its URL?
>> I'd like to take a look.

> http://www.promelec.ru/pdf/LCWW51M.pdf

I'm not an expert on this subject (though I do know a little). My gut reaction
is this...

The color reproduction index is only 80. That's poor. That doesn't mean that
the LED won't work -- but it will probably need appropriate filtering that
won't be easy to achieve.

The spectral emission (p11) isn't particularly flat -- and definitely not
smooth -- no doubt one of the reasons for the poor CRI.

I don't think you're going to get pleasing results.

[N_Cook]

On 27/09/2013 18:35, Jeff Liebermann wrote:
> On Fri, 27 Sep 2013 14:34:59 +0100, N_Cook <div...@tcp.co.uk> wrote:
>
>> Then I intend in the first instance to buy 5x 1.2W white LEDs, 3500K, 20
>> degree, for proof of concept. (...)
>
> I've done this with marginal sucess. The problem is focus. The
> original light has all the light coming from roughly a single point.
> An array of 5 LED's will distribute the light over a much larger area.
> It will work well with light from the central LED using the original
> reflector, but the outer LED's will be wasted and splattered all over
> the room.
>
> You don't really need the original reflector if the light source has
> its own forward facing reflector. Try cramming an MR16 bulb in place
> of the projector bulb and reflector. The smaller size MR16 lamps
> might fit.
>
> More:
> <http://www.instructables.com/answers/Change-a-projector-lamp-to-LED-/>
>

All the discharge lamps in video projectors , I/ve seen have an
electrode and squashed , not optically conductive glass, axial exactly
in line to where you want the light to go.
With directional 20 degree central LEDs, and lensed 4 degree ones
off-axis. will direct most of the energy directly to the half inch
aperature , without any reflectors . Reflectors just to mop up spill over .
I can see some high power red LEDs being added to counter the blue sub=peak

[Jeff Liebermann]

On Fri, 27 Sep 2013 19:56:58 +0100, N_Cook <div...@tcp.co.uk> wrote:

>All the discharge lamps in video projectors , I/ve seen have an
>electrode and squashed , not optically conductive glass, axial exactly
>in line to where you want the light to go.

True. However, the lamp I was replacing originally looked like these:
<http://www.porters.com/general-accessories/projector-bulbs/projector-studio-bulb-dyh.html>
<http://www.porters.com/general-accessories/projector-bulbs/eys-projection-lamp.html>

Note that some LED projectors use RGB LED's with three PWM modulators
to control the output level of each color LED in order to get a better
looking "white". In particular, the micro DLP projectors use RGB
LED's. Some use white LED's but methinks they look awful on the
screen.

[Phil Allison]

"William Sommerwanker"

>
> I'd like to point out that is no such thing as -- nor can there be -- a
> white LED. LEDs are necessarily limited to a narrow band of wavelengths. *
> All (???) white LEDs are (I assume) a blue LED with a yellow-fluorescing
> phosphor. **
>
> This /looks/ white to the eye, but the red and green wavelengths needed
> for color reproduction aren't present.

** As fucking usual, the Somerwanker fool just makes stuff up.

Anyone can Google "white led" and get the facts.

There is plenty of green orange and red in the light from regular white
leds.


.... Phil

[Arfa Daily]

"N_Cook" <div...@tcp.co.uk> wrote in message
news:l241hv$vvk$1...@dont-email.me...

> Assuming over-riding the opto couplers to falsely confirm to the system
> micro that the arc is struck and the lamp is lit (maybe requiring a delay)
> firstly, with the lamp ps disconnected.
> Then I intend in the first instance to buy 5x 1.2W white LEDs, 3500K, 20
> degree, for proof of concept. Assuming that sort of works then get perhaps
> 10 more, going down to 2700K or 3000K or perhaps (unlikely) 4000K and
> lenses to colimate to 2 degrees. Set inside a reversed conical silvered
> glass of an ex-lamp to direct spillover light into the colourwheel/light
> tunnel aperture.
> The intended LEDs are 11x10mm footprint so can be mounted quite close to
> the colourwheel(for 5 anyway) on a spherical back mount. I may as well
> retain the original fans, perhapps knocked back a bit for less noise
> intrusion later on.
>
> When coming to scaling up I originally was thinking of using a sectored
> curvi-linear silvered reflector from PIR units (with faned air cooling)
> but have since come across 2 degree lens converters for these LEDs so may
> as well go with them and shine directly from a larger spherical backing
> mount, directly to the colourwheel aperture.
>
> I'd be interested in any suggestions or comments other than of the I would
> not bother type of replies.

Sorry to be one of those people, but based on some experiments that I've
recently been doing with high power LEDs, I think you are going to be
pissing in the wind. A few watts worth is not going to come close. I have
been playing with some 10 watt types with appropriate collimating reflectors
and lenses. Whilst they are 'blinding' to look at directly, you could easily
do it with a pair of sunglasses on. You most certainly could not do that
with a 200 watt discharge lamp. Also, they require substantial amounts of
directly fan-cooled heatsinking, which makes the assembly physically quite
large. A further problem with high power LEDs, is that they are made from
multiple chips on a single die. This actually makes it rather difficult to
get an even density light from them. Because they are substantially
flat-plane light radiators, the light tends to remain in 'dots' through the
collimating and focusing optics.

I do a lot of work on pro and semi pro lighting fixtures - such as moving
heads of the type that you see in use on TV shows like Strictly and
X-Factor. The ones at the small to medium end typically use discharge lamps
in the range 150 to 575 watts. There are now some at the lower end of the
market which use LEDs, and I can tell you that no matter how powerful a LED
that they employ, they cannot hold a candle (Ha!) to the 'real deal' with a
discharge lamp in them.

So, whilst you may get some results that are just about acceptable in the
right circumstances, I honestly feel, based on practical experience, that
you will get anywhere near matching the performance of the discharge lamp
originally fitted.

Arfa

[Arfa Daily]

"N_Cook" <div...@tcp.co.uk> wrote in message

news:l245i3$n48$1...@dont-email.me...

That triangular diagram that you see with red, green and blue respectively
at each corner and white in the middle, and intended to show every possible
colour that can be derived from additive mixing of those three colours, is
called a chromaticity diagram. It famously used to be used to show that a
colour CRT cannot (truly) produce brown.

Arfa

[Arfa Daily]

"N_Cook" <div...@tcp.co.uk> wrote in message

news:l24kdo$gdc$1...@dont-email.me...

My experiments have shown that the use of a collimating reflector
specifically designed for the LED package being used, brightens the forward
beam significantly ...

Arfa

[William Sommerwerck]

"Arfa Daily" wrote in message news:Ilq1u.3812$ku4....@fx25.am4...

> That triangular diagram with red, green and blue at the corners

> and white in the middle, and intended to show every possible colour that can
> be derived from additive mixing of those three
> colours, is called a chromaticity diagram. It famously used to be
> used to show that a colour CRT cannot (truly) produce brown.

You've never seen a '70s RCA set? Brown was about the only color it /could/
produce (along with some blues and yellows, if I recall correctly).

Brown is actually a very dark red.

[N_Cook]

Have you tried the video projector use rather than Gobo type things
where you are not trying to squeeze light along a small aperature light
tunnel? I've not found the data out there but I suspect the vast
majority of the light available to a gobo setup just does not get into a
light tunnel setup , so if you can direct all your LED lamps into that
tunnel then the overall requirement is much lower than normal ratings
would suggest.
The use of this video projector is for text and graphics so colour
rendition of the likes of flesh tones is not too critical, very rarely
showing any video as such.

[N_Cook]

Intended use in the main part is for projecting text and graphics so as
long as there is a colour difference, any colour difference almost,
rather than correct colour rendering that is all that is required , a
rare pic with a green flesh tone or something does not really matter too
much

[N_Cook]

I've moved away from thinking about using lenses as they restrict the
footprint size. If I double stack the LEDs then a spacing of centres
about 8.5mm is possible and so 14 LEDs in a 32mm diameter. So can be
quite close to the light tunnel and 20 degree beam spread is fine and
outer LEDs approach angle will still only be 30 degrees or so, and a
reasonable proportion of that will reflect only a few times and
substantially get to the DLP chip. Will still try 5 LEDs initially.
Will power up individually at only 100mA or so and set the angles of
each individual LED for maximum brightness at a simulated window with a
photodiode , then wire all in series and make a more substantial back
mount before transfering to the projector

[Trevor Wilson]

**What a waste of time and effort. The best LEDs are approximately
similar efficiency to that of halide lamps. As others have stated, the
big problem will be that you are substituting a compact light source
with a rather diffuse one. The optics are not designed for such use.

--
Trevor Wilson www.rageaudio.com.au

[N_Cook]

But the lamps used in video projectors are ,in effect, not compact. The
direct light path from the reasonably compact source is blocked by an
electrode and non optical structural glass lump, relying on the mirror
surface of the light tunnel / light pipe to average out/balance-up the
light coming in at all sorts of angles, off the parabaloid reflector

[Arfa Daily]

"William Sommerwerck" <grizzle...@comcast.net> wrote in message
news:l25c55$adg$1...@dont-email.me...

ISTR from my college days that brown is known as a non-spectral colour, and
cannot truly be produced by mixing R, G and B in any proportion, and this is
shown by the chromaticity diagram. Rather, it is a perceived colour that is
'worked out' by the brain, based on experience and surrounding colours.

Arfa

[William Sommerwerck]

"Arfa Daily" wrote in message news:MQ42u.8296$je2....@fx14.am4...

"William Sommerwerck" <grizzle...@comcast.net> wrote in message
news:l25c55$adg$1...@dont-email.me...
> "Arfa Daily" wrote in message news:Ilq1u.3812$ku4....@fx25.am4...

>> Brown is actually a very dark red.

> ISTR from my college days that brown is known as a non-spectral colour, and
> cannot truly be produced by mixing R, G and B in any proportion, and this is
> shown by the chromaticity diagram. Rather, it is a perceived colour that is
> 'worked out' by the brain, based on experience and surrounding colours.

I'm not sure about that.

When I said "very dark", I meant having a low value. The chromaticity diagram
does not include value -- only hue and chroma. "Brown" is how the eye
interprets reds of low value.

[Trevor Wilson]

**NO. By the time you try to shove 200 Watts of LEDs into the enclosure
(including apprpriate heat sinking) You're not going to be able to focus
the whole thing properly. It's a daft idea, unless you are prepared to
use MUCH less LED power (say 15 Watts) and a consequent huge drop in
Lumens.

BTW: The light from a parabolic reflector does not come off at all sorts
of angles.

--
Trevor Wilson www.rageaudio.com.au

[N_Cook]

That Osram with built in lens is discontinued, only came out 3 years ago.
I'm getting 7 of the LCW W5SM, white 2700K 120 degree and matching 7 off
6 degree hex shaped lenses.
The off the shelf 7 cell hex cluster lens is for parallel , not focused.
Using a 5 to 6 inch ball as a jig I'll combine the 7 as a focused cell.
With the lenses at 85% transmission, brings the 75 lumen per LED down to
64 lumen, so x 7 =450 lumen. Some heatsinky type protrusions added to
the LEDs to catch the fanned air.
When new the projector was rated 2000 lumen, although still taking 200W
, the light output is now much less. Combined with the poor optics of
these lamp setups I suspect fully directed into the light pipe 450 lm is
not much different to the present discharge lamp situation. Still plenty
of room to add another 6 plus lenses around the periphery to bring up to
900 lm.
Playing around with a scrapped colour wheel dicroic disc and assorted
white LEDs the red transmission , to eye anyway , is a lot lower than G
and B.
So I will get a number of red 100mA 5mm , 15 degree standard size LEDs
to add red, perhaps 6 at the interstices of the lenses, mounted to the
rear and between the SMD LEDs plus maybe another 6 around the periphery
to infill.
Good progress with the silvered "cone" for mop-up, front of PAR lamp
removed and bulb removed, about 3/4 way through grinding through the
thick glass with cintrided disc, to remove the barrel part. Previous
attempt with thinner glass photoflood failed. If I was brave or had a
load of these sort of lamps, I would try the old bottle cutter routine,
freezer spray and a ring of "fuse" wire around , fired up for the cut

[N_Cook]

Well that was very successful, a job I've never done before. Not a cone
but the nearest I could find with
a good silvered internal surface and right sort of dimensions. The
thinnest part of the glass 4.5mm thickening to 7mm as 12 flutes around
the stem, but a neat ground-glass cut.
So I have a spillover reflector with 70mm internal diameter available
for the LED assembly, down to 21mm diameter opening for the colour wheel
aperature (from memory about 12mm) and 43mm axially.
It will be a couple of weeks before I can get some time to convert the
projector . But in the meantime anyone any ideas how to measure the
intensity of the LED assembly at the axis and focus of the array, with
any sort of accuracy (no known "standard candles" etc in my
possession)?, for anyone else coming down the same path. My uncalibrated
luxmeter , I doubt goes that high plus probably would melt, as would any
of the plastic neutral density filter I have and placed in the path of
that beam

[hrho...@sbcglobal.net]

How about some photos of what you are doing, most of what you are describing is WAY over my knowledge of optics and lenses.

[N_Cook]

On 30/09/2013 17:10, hrho...@sbcglobal.net wrote:
> How about some photos of what you are doing, most of what you are describing is WAY over my knowledge of optics and lenses.
>

Its more bodging than optics. I'll take a few pics along the way.
I've just noticed on the LED lens makers datasheet if you put 7 of their
1.2W white light LEDs in a specialised version of one of their lens
structures , as I will be doing in a different manner, and directing to
a 12mm waist , you end up with 3,000,000 lux there . All I need then is
some deuterium pellets.
I think I'll need more than neutral density 4 stop Lee Filter , I just
tried black silicone rubber sheet and that is more like x0.001 light
attenuation with an odd colour cast from white LED

[John-Del]

On Friday, September 27, 2013 9:41:54 PM UTC-4, William Sommerwerck wrote:


> You've never seen a '70s RCA set? Brown was about the only color it /could/
>
> produce (along with some blues and yellows, if I recall correctly).

You don't recall correctly...

RCA color TVs were always the most accurate, with a single exception: the CTC38 (I'm pretty sure about the number, that was over 40 years ago) was a low end toilet made for two years for big stores and buying groups and had a tube lineup distinctly different from the better models, and they were made in the 60s not 70s. By 1971, RCA was running the extremely accurate and reliable XL100, or the mostly transistorized hybrid XL (sweep tubes only), which also was an excellent performer.

Mid 60s Zeniths were known for crappy color as they aged, but would respond well to replacing the demodulator transformers and doing a full color alignment.

[William Sommerwerck]

"John-Del" wrote in message
news:83e8ff7f-c8da-4bfe...@googlegroups.com...

On Friday, September 27, 2013 9:41:54 PM UTC-4, William Sommerwerck wrote:

>> You've never seen a '70s RCA set? Brown was about the only color it
>> /could/ produce (along with some blues and yellows, if I recall correctly).

> You don't recall correctly...

Oh, but I do. I might have the decade wrong, but there was a time when RCA
sets had horrible color. Why, I don't know. My memory is that they were the
most-common color TV in the motels where I stayed when travelling for Bendix.
They were invariably tres-lousy.

I saw a CTC-100 maybe 45 years ago, and I remember it having an excellent
picture.

[gregz]

One of my projects was making a light source with multiple colored 5 watt
LEDs. I was also considering white LEDs. First test was using fiber optics.
Problems in getting an even field, trying different lens, diffusors. Second
attempt was using reflectors. Since the project required a fairly compact
unit, I probably would need fluid cooling. Project stalled, but its still
in my mind.

Greg

[N_Cook]

By 5W I supppose you mean co-planar ready-made assembly
http://docs-europe.electrocomponents.com/webdocs/0d08/0900766b80d0828a.pdf
has some cell cluster focusing devices.

[chuck]

On Mon, 30 Sep 2013 15:38:22 -0700 (PDT), John-Del <ohg...@aol.com>
wrote:

The CTC38s were made from 1969 through 1970. The color demodulator
had a wide angle in the flesh tone area so flesh tones looked
"natural" even if the tint shifted slightly. Yellows were reproduced
as orange because of this feature. The solid state set in 1971,
except for the hv rectifier, was the CTC40. It wasn't like the
following XL100 line because the chassis wasn't modular. Some had an
issue with the color killer circuit killing the color on a normal
color signal. Chuck

[Trevor Wilson]

**The largest LED array I've used is a 100 Watt array (approx 25mm X
25mm). The cooling system is a fan assisted CPU cooler. The whole lot is
almost double the size of a 250 Watt halide projector lamp (Then there's
the 33 Volt 3 Amp supply. It occupies another 100cc) and reflector. It
delivers around half as much light output as the halide lamp. It is
measurably brighter than a 500 Watt halogen flood lamp. Then there's the
33 Volt 3 Amp supply. It occupies another 100cc.

When using RGB LEDs, I've found that it is best to use a translucent
panel to mix colours.

--
Trevor Wilson www.rageaudio.com.au

[Arfa Daily]

>>
>
> **The largest LED array I've used is a 100 Watt array (approx 25mm X
> 25mm). The cooling system is a fan assisted CPU cooler. The whole lot is
> almost double the size of a 250 Watt halide projector lamp (Then there's
> the 33 Volt 3 Amp supply. It occupies another 100cc) and reflector. It
> delivers around half as much light output as the halide lamp. It is
> measurably brighter than a 500 Watt halogen flood lamp. Then there's the
> 33 Volt 3 Amp supply. It occupies another 100cc.
>
> When using RGB LEDs, I've found that it is best to use a translucent panel
> to mix colours.
>
> --
> Trevor Wilson www.rageaudio.com.au
>

I've recently been playing with a 30 watt RGB LED. It's a similar size at
around 25 x 25 mm, and each 'channel' comprises 10 individual LED chips in a
vertical line. I'm using a collimating reflector and lens made to go with
it, and the heatsink supplied with it as part of the package. It is a
heavily finned 'cube' about 50 x 50 x 60 mm and the makers state that it
requires force cooling - and it does - so that adds another 15 mm in fan
depth, and as you say, then there is the power supply.

The reflector does a good job of collecting all of the output from the die,
and the lens does a similarly good job of producing a basic beam. However,
because the R, G and B LEDs are arranged in parallel lines, the colour
mixing, as you have discovered, is poor, and the individual colours are
patchy. I found that this could be completely overcome with only a very tiny
reduction in perceived output, by placing a sheet of translucent polythene
under the face of the lens that is the LED side. I'm talking the stuff
that's like builder's polythene here. Opaque enough that you can't see
detail through it, but still very neutrally light transmissive.

In my experience, LEDs are funny old things when it comes to light output.
As a 'for instance'. LED torches (flashlights) are so bright that you can't
look at them. And yet they are poor at producing a light to see by, and do
little to produce any overall lighting in comparison to a standard
incandescent torch bulb. Basically, go into a dark room with a conventional
torch and a LED torch, and you will see better with the conventional torch.
I have a 10 watt white LED that I've also been playing with, and for some
weeks, it has been sitting on the bench just running. On several occasions
when I have dropped screws etc that have rolled under the bench, I have
picked it up with its power supply, and taken it down to the floor. It
lights the area under the bench like daylight, and yet fallen parts are
still more difficult to spot than they are with a conventional torch. It
might be something to do with either the colour of the light, or the very
stark shadows that it creates ...

Arfa

[Trevor Wilson]

On 2/10/2013 11:28 AM, Arfa Daily wrote:
>
>
>>>
>>
>> **The largest LED array I've used is a 100 Watt array (approx 25mm X
>> 25mm). The cooling system is a fan assisted CPU cooler. The whole lot
>> is almost double the size of a 250 Watt halide projector lamp (Then
>> there's the 33 Volt 3 Amp supply. It occupies another 100cc) and
>> reflector. It delivers around half as much light output as the halide
>> lamp. It is measurably brighter than a 500 Watt halogen flood lamp.
>> Then there's the 33 Volt 3 Amp supply. It occupies another 100cc.
>>
>> When using RGB LEDs, I've found that it is best to use a translucent
>> panel to mix colours.
>>
>> --
>> Trevor Wilson www.rageaudio.com.au
>>
>
> I've recently been playing with a 30 watt RGB LED. It's a similar size
> at around 25 x 25 mm, and each 'channel' comprises 10 individual LED
> chips in a vertical line. I'm using a collimating reflector and lens
> made to go with it, and the heatsink supplied with it as part of the
> package. It is a heavily finned 'cube' about 50 x 50 x 60 mm and the
> makers state that it requires force cooling - and it does - so that adds
> another 15 mm in fan depth, and as you say, then there is the power supply.

**Exactly. LEDs are certainly efficient. Far more efficient than any
incandescent lamp. Discharge lamps, particualarly halides, are a
different matter entirely. LEDs are (presently) not more efficient than
halides or sodium vapour lamps. Of course that may change.

**I disagree. One of my torches uses a 2 Watt halogen bulb. It produces
excellent light output, though the reflector tends to provide a pretty
poorly defined pattern. It can be focussed within limited ranges. By
contrast, one of my 1 Watt LED torches blows it away, in every area. In
fact last week, I picked up a 1 Watt LED torch for 7 Bucks, which has a
focus attachment. It is astonishingly good. Except at it's narrowest
focus setting. The rectangular LED chip is easily seen on a wall at 100
Metres. At 2 Metres, the 'dot' is 100mm X 100mm. At it's widest focus
setting, the 'dot' is 2 Metres in diameter. It's so handy I'm buying a
bunch more. I will avoid incandescent torches in the future.

--
Trevor Wilson www.rageaudio.com.au

[Trevor Wilson]

On 2/10/2013 11:28 AM, Arfa Daily wrote:
>
>
>>>
>>

**BTW: This is the torch I spoke of:

http://www.ozstock.com.au/8108/Super-FREE-Ozstock-Day--CREE-LED-Powered-Torch-with-Adjustable-Lens.html

You may find one locally. It's a bloody rip-snorter.

--
Trevor Wilson www.rageaudio.com.au

[N_Cook]

One of those that if you close focus , you can start your campfire
without having to rub two boyscouts together?
an example of the focus mechanics shown in here
docs-europe.electrocomponents.com/webdocs/0d08/0900766b80d0828a.pdf

[Arfa Daily]

>
> **BTW: This is the torch I spoke of:
>
> http://www.ozstock.com.au/8108/Super-FREE-Ozstock-Day--CREE-LED-Powered-Torch-with-Adjustable-Lens.html
>
> You may find one locally. It's a bloody rip-snorter.
>
> --
> Trevor Wilson www.rageaudio.com.au

I'm glad it's "Plash resistant" and has a "Tactical switch". They should be
useful features ... ! :-)

Seriously though, it is a somewhat different design to ones that I've seen
previously, so may be a considerable improvement. It does seem to be a
technology that's evolving quite quickly.

Arfa

[N_Cook]

I now physically have the LEDs and lenses. 2 immediate problems, both
active faces of the lenses are dead flat. In the pdfs it looked as
though the front faces were surrounded in a ring and I assumed (pdfs not
clear pics) the 4 corner holes of the LEDs would mesh with pips on the
rear of the lens.
They are made for mounting to pcbs not the other way round, so no
provisions for that. So I have to find some 12mm or so diameter thinn
rings to align the front faces to my 5 inch cistern ball valve float as
spherical former, and make some sort of jig for aligning the LEds to the
lenses , plus fixing them together

[N_Cook]

I'm not used to optically pure plastic, I would have sworn that
examining the LED side of 2 of the lenses then it was flat faced, but
not touched the surfaces, and they contain recesses.
I now have some rings for placement.
The datasheet does not explain the normal placement. LED soldered to
pcb, a non-optical plastic holder placed over the LED, quite loosely.
The holder is .4mm undersized so forcing the lens into it, then
compresses the other end around the LED with little pip under each
corner, but no use made of the 4 holes in the corners.
I think I've worked out how to adapt those holders for my purposes.

[Trevor Wilson]

On 2/10/2013 6:35 PM, Arfa Daily wrote:
>
>
>>
>> **BTW: This is the torch I spoke of:
>>
>> http://www.ozstock.com.au/8108/Super-FREE-Ozstock-Day--CREE-LED-Powered-Torch-with-Adjustable-Lens.html
>>
>>
>> You may find one locally. It's a bloody rip-snorter.
>>
>> --
>> Trevor Wilson www.rageaudio.com.au
>
> I'm glad it's "Plash resistant" and has a "Tactical switch". They
> should be useful features ... ! :-)

**What are you going to do? Spelling is not what it once was. One of my
regular buyng sites is a very large Aussie retailer. It appears they
employ copywriters whose first language is not English.

>
> Seriously though, it is a somewhat different design to ones that I've
> seen previously, so may be a considerable improvement. It does seem to
> be a technology that's evolving quite quickly.
>
> Arfa

**Indeed. Here is where I get the some really nifty torches:

http://dx.com/

A nice aspect of the site are the uncensored reviews of their products.
Delivery is slow, but free. This is an immensely impressive torch:

http://dx.com/p/ultrafire-th-t60-ha-ii-xm-lt60-5-mode-1200-lumen-white-led-flashlight-with-strap-1-x-18650-57007

It does us special LiIon batteries though. About 3 Bucks each. The
special charger is another 6 or 7 bucks.

These things are astonishingly good:

http://dx.com/p/12w-7000k-800-lumen-white-led-emitter-metal-strip-12-14v-80512

Almost twice as bright (measured with a light meter) as an 11 Watt T5
fluoro lamp. They must be glued to a small flat piece of aluminium heat
sink, but, even then, they are exceptionally compact. I've purchased
dozens of these. I cannot recommend them more highly. Awesome product.
My neighbour uses them in his camping trailer.

And here is the 100 Watt LED emitter I purchased:

http://dx.com/p/jr-100w-w-100w-9000lm-6500k-white-light-10-x-10-led-module-30-36v-173825

It requires a separately available 3 Amp, constant current source.
Easily replaces one of those 500 Watt halogen work lights.



--
Trevor Wilson www.rageaudio.com.au

[N_Cook]

Supplied in small numbers , the lenses are supplied pushed into the
mounts and again they don't say how to remove them without damage to the
lens.
First one bodged by placing over a couple of metal plates providing the
across-flats 12.9mm gap to then push down as detailed below. As stated
previously you lock the holder to the pcb in normal use, by pushing the
lens into the holder , so first they have to be separate.
Then with 1 free holder, place back-to-back castellation to castellation
over the next one. Place a flat piece of rubber into the slot part that
takes the LED (so not to damage the thin lens wall) and push down quite
hard with a rod, until the lens pops the 1mm into the precise recess of
the other holder. Remove the second holder by hand and then grip the
lens across the pre-existing mold marks and pull out from the first
holder with serrated edge pliers.
Well that is my method for Osram Golden Dragon lenses made by Polymer
Optics Ltd as supplied by RS

[N_Cook]

The focused 7 cell honeycomb lens came together well. Doing the maths
and having a wedge tapering to .3mm seemed ok but trying to adapt
plastic to those sorts of dimensions is not practical. Having to mould
my own mounts.
The 2700K LEDs are noticeably cream yellow colour to the eye and seem to
have supressed the blue peak, too much?
Relative intensity through a dicroic colourwheel
R 340
G 270
B 070
even the reflection off the blue filter, ie complement colour of yellow
, is noticeably brighter than the reflections off the R and G sections.
I was expecting to add 5mm red LEDs but looks as though it will have to
be blue ones. Won't know for sure until the video projector has a
reasonable block of time to get inside to mess about.

[N_Cook]

As my mouldings to fit LED to lens are egg-cup shapes , a 3 part mould
required, letting epoxy harden before running off 7 of them, so far so good.
I was impressed with just trying one LED at 1/4 power of 90mA (no
heatsinks yet) and 5 feet away , bright enough to read by just.
Add a lens at the correct position and a neat bright foot by foot
"pixel" , of the chip thrown on a screen 5 foot away, probably as bright
as the projector showing white (DLP losses unknown).
So 7 of them and 4 times as bright would illuminate a 5 x 4 foot screen
, with that brightness. If 50% loss in hte projector then add another
ring of 6 , room in the "funnel" reflector for them if required.
I wonder what a gobo type thing made of a matrix of single RGB LEDs ,
with lens arranged to throw foot x foot squares with 6 inch overlap ,
would look like if driven with graphical/animated "video" pulses

[gigo.bl...@gmail.com]

any more on this? any luck?
would love some pics to see the progress

[N_Cook]

On 24/03/2014 07:10, gigo.bl...@gmail.com wrote:
> any more on this? any luck?
> would love some pics to see the progress
>

It had enough light for domestic use but not enough for more than 2m
diagonal. I got the 60 or so LEDs and lenses for a Mark 2 version but
have been inundated with other work. And as have repaired a number of
600x800 vid projs along the way, I'm not desparate to get the HD one
working. The use tends to be just for projecting bullet-point script anyway.
I assume you've seen the pics URL'd here. Single compound LED built
around a 5 inch ball valve float. Mark2 would be 19-1 built around small
christmas bauble as basis. The central lens not having an LED but used
to pass light from a similar cluster behind it which also has a cluster
behind it. As long as the light falls in the well of one of those lenses
then its collimated to about 3x3mm focus, ie within the light tunnel
entry aperture

[N_Cook]

On 24/03/2014 07:10, gigo.bl...@gmail.com wrote:

> any more on this? any luck?
> would love some pics to see the progress
>

I worked out how to arrange the 19 lenses over a much tighter radius
surface. Setting some lifted off the sherical surface a few mm, so not
as elegant looking cluster

[N_Cook]

pics etc on later thread, titled
Converting discharge lamp to multi-LED for video projector (maybe)

[RobertMacy]

On Mon, 24 Mar 2014 00:49:00 -0700, N_Cook <div...@tcp.co.uk> wrote:

> ..snip...

> I assume you've seen the pics URL'd here. Single compound LED built
> around a 5 inch ball valve float. Mark2 would be 19-1 built around small
> christmas bauble as basis. The central lens not having an LED but used
> to pass light from a similar cluster behind it which also has a cluster
> behind it. As long as the light falls in the well of one of those lenses
> then its collimated to about 3x3mm focus, ie within the light tunnel
> entry aperture

just saw this thread. back in the 70's while visiting Varian in Palo Alto,
CA I met the inventor of the xenon arc light. He was looking for other
applications than 'tank' lights for this formidable light producer. He had
mounted it inside a 16mm projector to replace the 'hot' bulb presently
used. The projector spread the movie images over a 20 ft wide screen in
the brightly lit lab, yet the film was easily viewable in that light! and
the blues were incredible. and you could freeze frame WITHOUT burning a
hole in the film.

That arc light is also used in medical applications down tubes for
lighting endoscopy, etc. and in microscope platforms.

I think the arc light is available commercially at several places,
incuding those outlets like Edmund Scientific. It's a small cylinder with
ring contacts on front and back. I have one somewhere it's approx 1.5 inch
long by 1 1/4 diameter has a builtin reflector for throwing the light
forward. From memory the arc, once fired runs on something like 10A at
12Vdc, or so. But the light can be used on your off road vehicle to see a
mile ahead [again from memory] and having no filament, quite robust.

Not so much to distract your efforts, but worth looking at. Oh, one down
side. The light is so bright it creates ozone across the surface of the
bulb. and ozone and the aluminum parts in the projector didn't get along
so well. But still alternatives to think about.