Brown led exposure system

[Gilligan]

Hey,

A photopolymer is a very fast exposure and will expose with several wave lengths. Many of which are commercially available. Dual cure emulsions are not as sensitive to such a large band of wave lengths. They preform the best when exposed to a wave length shift the NM up by 10 and they will no longer perform at all!!!! Many of the led EXPO units have a disclaimers, they will expose a photopolymer in 30 seconds or less. And for some emulsions it could be 1-5 minutes or higher.  These exposure units are using commercially available sources. Simply upping the wattage without the correct wave length will not help.

Under Cutting:
The use of reflectors is counter productive to this concept.  The goal is to get the cleanest light and not bounce light all over a enclosed box.  However in the chase for speed many have chosen to bounce the light of reflectors as to not waste any energy. We used s light modeling software placing a led in a pattern taking into account the angle and cone that the LED produces the each beam of light covers a 4" x 4 " area. Of course there is always a small overlap, with the modeling software we are able to ensure that where that small overlap occurs the intensity of light is +/- 10%.  I will post the graph on what it looks like once the light is measured.

Side note: The wattage of our system to expose a dual cure that fast is: 560 watts (in this case you have worry about proper heat sinks. Try a diazo, let me know how fast you can expose it and how clean.

Also send me a message with your info and I will send you a screen back exposed.  Please mail the art with the below picture to:
Brown Manufacturing
Attn : Steve
4661 Stafford
Grand Rapids, MI
49548

Thanks

Steve,

of the two commercially available units I tested (with spectrometers), light field was at 5% and 1% fluctuation. If you are saying that you have a 10% variance in the strength of your light field on the glass, that is too much. Did I misunderstand something?

pierre

Hey Pierre, how does the 3140 compare?

[blue moon]

Hey,

A photopolymer is a very fast exposure and will expose with several wave lengths. Many of which are commercially available. Dual cure emulsions are not as sensitive to such a large band of wave lengths. They preform the best when exposed to a wave length shift the NM up by 10 and they will no longer perform at all!!!! Many of the led EXPO units have a disclaimers, they will expose a photopolymer in 30 seconds or less. And for some emulsions it could be 1-5 minutes or higher.  These exposure units are using commercially available sources. Simply upping the wattage without the correct wave length will not help.

Under Cutting:
The use of reflectors is counter productive to this concept.  The goal is to get the cleanest light and not bounce light all over a enclosed box.  However in the chase for speed many have chosen to bounce the light of reflectors as to not waste any energy. We used s light modeling software placing a led in a pattern taking into account the angle and cone that the LED produces the each beam of light covers a 4" x 4 " area. Of course there is always a small overlap, with the modeling software we are able to ensure that where that small overlap occurs the intensity of light is +/- 10%.  I will post the graph on what it looks like once the light is measured.

Side note: The wattage of our system to expose a dual cure that fast is: 560 watts (in this case you have worry about proper heat sinks. Try a diazo, let me know how fast you can expose it and how clean.

Also send me a message with your info and I will send you a screen back exposed.  Please mail the art with the below picture to:
Brown Manufacturing
Attn : Steve
4661 Stafford
Grand Rapids, MI
49548

Thanks

Steve,

of the two commercially available units I tested (with spectrometers), light field was at 5% and 1% fluctuation. If you are saying that you have a 10% variance in the strength of your light field on the glass, that is too much. Did I misunderstand something?

pierre

Hey Pierre, how does the 3140 compare?

3140 reads is smaller than out sensor size or tolerance can measure (so 0% for all practical purposes).

Just for the record, I don't see 5% being an issue. I would have to think about 10% though. My guess is, I am not reading something right. . .

pierre

[sben763]

Pierre, what would you need to measure my results, interested in doing.  Willing to pay for your time if you have it. 

[blue moon]

Pierre, what would you need to measure my results, interested in doing.  Willing to pay for your time if you have it.

measure the exposure unit or the film? If you send me the films, I'll read them for you (that offer and the file are in the screen making section).
To read the exposure unit, I'd have to bring the meters to your place which would be tough. If you wanted to drive it over here, we could test it and compare it to the 3140 and the other LED readouts I have. We can measure the light intensity at 365nm and I'd have to check the other meter to see what it's calibrated to. . .

pierre

[Steve Harpold]

Hey,
After, being that you have tested many units below is our testing method as well as a questions about the method you used to determine 1-5%.  And for those DIY a simple inexpensive test just for fun!!


1. Method to measure lower distribution:
         A. Molectron Thermopile
         B.  Why
                These devices are very Accurate and insensitive to variations in wavelength and acceptance angle. Using this method I can confidently list s variation of intensity between 5% and 10%. I have to defend this so it easier to publish worst case.

Spectrometer method:
Disclaimer*******
(Below is the question, followed by the reason for asking. Some of the questions will obvious to a person versed in light measurement. They are not intended to challenge ideas, just listed for those following along to understand why the questions were presented)
If I have a better understanding of you method of measurement I can report back the details and how it pertains to the Brown LEDX series.

1.       Where on the platen were the measurements made, directly above LEDs, or randomly placed over platen with a large number of measurements?  How many locations were chosen?
If the measurement was made directly over the LEDs, the variation measured would be that of the LEDs and not representative of the entire platen area.

2.   Did the spectrometer use a fiber optic?  If so, what is the acceptance angle of the fiber optic?  If the fiber does not have a cosine corrector, it will have a very narrow acceptance angle.  Which means it will not show the total amount of light at a point on the platen but only light from a narrow angle.  In other words, the light from adjacent LEDs will not be accepted into the fiber optic

3.  The variation in measurement of 1% to 5% is very questionable.  (Experience speaking which is always never the best idea!!!) In the field of optics and optoelectronics, a claim of 1% to 5% is very impressive when it comes to lighting.  Most good measurement systems do not have the ability to measure below +/- 2%, unless you are using high quality laboratory equipment with very tight controls on methodology.

After a quick review of your method I can apply it to the Brown Led unit and report back.

The DIY project!!!
aAway to make this type of measurement (relative power distribution)  on the cheap.
1.   Turn an exposure unit on its side
      A. Tape a large sheet of thin paper, at the corners, over a platen and turn on the U

2.  Look at the paper on the platen while it is running (I don't support staying in uv light!!!)
         A. The human threshold for observing variations in intensity is about 20%
         B.  Some of these exposure units will show defects visibly

3. Experiment continued for software nerds!!!
         A. Assuming it passed the eye test than we can pretty much expect the unit to be better than 20%. The next percentage points are not so easy to earn.
         
        B. From a distance of 10 ft away take a picture of the platen with

         C. Zoom into the platen with camera and adjust distance from the platen so the resulting image is not over exposed.

         D. Use image processing software to plot the relative intensity of the image over the entire field
         
         E. Software options:
                      1. Matlab, Zemax, Freemat, etc

          F. Attached is the Zemax illustration of the Brown LED series expo unit.

I always enjoy other thoughts and questions on how arrived at my conclusions.  Let me know what you think about or testing operation as well as you experiences on your method of testing!



 

[Gilligan]

Great stuff Steve... I love that you are engaging ina friendly manner with the users here!  Great spirit!

I'm also glad to read about that paper method.  It is one that I had thought of to test units with odd spacings between LEDs.  I didn't realize we would only detect 20%... Good to know.

The camera technique is great, I'd suggest under exposing the picture a healthy bit to make sure you aren't "cheating" on accident as washed out images will read flat.

Great stuff!

[Steve Harpold]

I haven't figured out how to include other peoples message in the purple box.

TCT to answer your question:
Model: LED 2962
Cap: (2) 25x36 frames
Times: 15-25 photo  dual 1:45 - 2:00 (2:30 hsa/waterbase)
Cost: 7,295

Model: LEDX 2962
Cap: (2) 25x36
Times: photo: 1-15s  dual 45 - 1:15 (1:30 hsa/waterbase)
Cost: 9,295

[Frog]

I haven't figured out how to include other peoples message in the purple box.

Here you go

[ebscreen]

Holy chit, actual science from a manufacturer! Brown from the backfield!

Why no diazo emulsions with LED? Under cutting too much of an issue at the exposure lengths necessary? Or just that much time isn't saved over metal halide?

[Steve Harpold]

Holy chit, actual science from a manufacturer! Brown from the backfield!

Why no diazo emulsions with LED? Under cutting too much of an issue at the exposure lengths necessary? Or just that much time isn't saved over metal halide?

See post 1 and reply #7. 

[blue moon]

Steve,
Great info!
The measurements were taken by Richard Greaves and myself over last year or so. We used three different instruments, one of which is a laboratory grade $2k+ UVA/UVB meter. Richard also has a meter by Chromaline, I think, and I have a generic 365nm UV meter by General Instruments. They all have sensing elements in the head, attached with a cable to the main unit. Readings were taken in one inch increment across the field. All the readings were taken right on top of the glass while trying to keep the sensor flat against it. Considering all the meters read similar field uniformity, I would venture to guess the readings are right. I would NOT bet my life on it, these, after all, we're not laboratory conditions, but uniformity of the results, both at my shop and ISS floor leads me to believe we did OK.

I'll stop by the booth tomorrow and we can talk some more.

Pierre

[Gilligan]

Holy chit, actual science from a manufacturer! Brown from the backfield!

Yeah, I'm loving it... The guy can barely use the forum but isn't afraid to hop on here and let it all hang out and truly engage the people!

Not cherry picking the discussion either!

Very refreshing!  I've gained a good bit of respect for Brown over the past month!

[mk162]

Sonny and I were talking about Brown the other day and how much they have really stepped up their game.  I am glad to see this. 

[Steve Harpold]

Steve,
Great info!
The measurements were taken by Richard Greaves and myself over last year or so. We used three different instruments, one of which is a laboratory grade $2k+ UVA/UVB meter. Richard also has a meter by Chromaline, I think, and I have a generic 365nm UV meter by General Instruments. They all have sensing elements in the head, attached with a cable to the main unit. Readings were taken in one inch increment across the field. All the readings were taken right on top of the glass while trying to keep the sensor flat against it. Considering all the meters read similar field uniformity, I would venture to guess the readings are right. I would NOT bet my life on it, these, after all, we're not laboratory conditions, but uniformity of the results, both at my shop and ISS floor leads me to believe we did OK.

It was pleasure to speak with you today on the LED concept. I believe I have an understanding of your proposal and it seems logical.  Thanks for taking the time to illustrate the concept.  I have run the simulation, if you have time tomorrow stop by, the results are intriguing!!

Thanks

[blue moon]

Steve,
Great info!
The measurements were taken by Richard Greaves and myself over last year or so. We used three different instruments, one of which is a laboratory grade $2k+ UVA/UVB meter. Richard also has a meter by Chromaline, I think, and I have a generic 365nm UV meter by General Instruments. They all have sensing elements in the head, attached with a cable to the main unit. Readings were taken in one inch increment across the field. All the readings were taken right on top of the glass while trying to keep the sensor flat against it. Considering all the meters read similar field uniformity, I would venture to guess the readings are right. I would NOT bet my life on it, these, after all, we're not laboratory conditions, but uniformity of the results, both at my shop and ISS floor leads me to believe we did OK.

It was pleasure to speak with you today on the LED concept. I believe I have an understanding of your proposal and it seems logical.  Thanks for taking the time to illustrate the concept.  I have run the simulation, if you have time tomorrow stop by, the results are intriguing!!

Thanks

Hey Steve,

Pleasure meeting you today and I mean it! It is very refreshing to see somebody with the great new ideas and willingness to explore new concepts. 'Look forward to talking more tomorrow.

Pierre