LCD Based 3D Printer - Introduction

This is the place to discuss DLP projectors, UV Lasers, Galvanometers, LCD screens and similar display devices. Also discussed are optics in general.
hegykc
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Re: LCD Based 3D Printer - Introduction

Postby hegykc » Mon Mar 16, 2015 2:34 pm

Phife where are you with the monochrome panels? I would like to experiment with my own flexvat designs. I already have a laptop panel and controller board, 4k color monitor is on the way.. but I would really like to see what 66% more of the UV power can do when going with a monochrome panel. Can you offer these for sale now?

Phife
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Re: LCD Based 3D Printer - Introduction

Postby Phife » Mon Mar 16, 2015 2:53 pm


Oneminde
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Re: LCD Based 3D Printer - Introduction

Postby Oneminde » Tue Mar 17, 2015 11:35 am

@ Phife.
When you talked about VAT release the other day, I kinda misunderstood what you referred to, I understand what it is now. Just wanted to mentioned that.

hegykc
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Re: LCD Based 3D Printer - Introduction

Postby hegykc » Tue Mar 17, 2015 11:37 am

3d printing learning curve is a steep one indeed :D

Oneminde
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Re: LCD Based 3D Printer - Introduction

Postby Oneminde » Tue Mar 17, 2015 11:45 am


ubnt
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Re: LCD Based 3D Printer - Introduction

Postby ubnt » Sat Mar 21, 2015 10:42 am


Oneminde
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Re: LCD Based 3D Printer - Introduction

Postby Oneminde » Sat Mar 21, 2015 11:37 am


Phife
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Re: LCD Based 3D Printer - Introduction

Postby Phife » Wed Mar 25, 2015 7:56 pm

I will be placing an order for some LED's and LED drivers. I have about 20 V1 PCB's for sale. If anyone wants an LED Array with LED's and optics please shoot me a PM and I will order some extra parts.

V2 PCB's have been put on hold while testing of new LED's and optics proceeds. Will be several months before I even begin production of V2.

Cation
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Re: LCD Based 3D Printer - Introduction

Postby Cation » Sun Apr 19, 2015 3:19 pm

I'm hoping to clear up a bit of confusion of how the LCD panels work with lithography.

If you examine the structure of a LCD you'll notice that not all the light that
enters the display passes through the display. A RBG LCD pixel is actually made
up of three sub-pixels, red, green and blue plus the inter-pixel spacing where
no light is passed. As you can see from the following photos less than 1/4 of
the light that passes into the LCD gets passed through the Blue sub-pixel. The
green and red dyes in those pixels passes very little to no light under 500nm.
There are other losses involved but we won't get into that now.

Closeup comparison of the Retina LCD pixel structure.
http://preview.tinyurl.com/k5h3qta

Size of the pixels and inter pixel spacing of various Apple RGB LCD's.
http://www.kybervision.com/resources/Bl ... ucture.png

Most RGB LCD's are similar to the photos above. Just by area alone you'll see
that less than 1/4th of the light gets passed through the blue sub-pixels if
they were 100% efficient. This is one problem with using RGB LCD's for
lithography. You need to put at least 4X the light into them to get the
required light to trigger polymerization in the resin.

The blue dye used in the blue sub-pixel passes most of the light centered
around 460nm. If a mercury lamp is used the only portion of the spectrum
emitted is centered around 460nm. If a 400-410nm LED is used most of the light
will be blocked by the blue sub-pixel. This is far above the range of
"consumer" resins that are only sensitive up to ~410nm. Resins that are
sensitive to over 470nm will cure just fine with either a mercury lamp or low
cost 460nm blue LED since the light gets passed through the blue sub-pixel.

Monochrome LCD's are similar to the RGB LCD's in that they have pixels and a
inter-pixel dead space where no light is transmitted. The monochrome LCD's do
not have three sub-pixel they only have one pixel.

Closeup of the pixels in the monochrome LCD used for Epson projectors:
http://cineforhome.com/reviews/projecto ... /Pic70.jpg

The large monochrome LCD's are very similar in arrangement, only the pixels are
much larger. The Epson monochrome 1" used in projectors and the large monochrome
LCD panels pass much more of the light that enters them since the actual pixel
area to dead or filtered area is much greater. They are all designed with
materials that pass light over 420nm very well. Large monochrome and Epson 3
-LCD projectors all work very well with no modifications with resins that cure
over 420nm.

The Epson LCD projectors use a blue 460nm filter with the blue LCD. Take a look
at how they work here:
http://cineforhome.com/reviews/projecto ... Review.htm

The large monochrome LCD panels use filters and polarisers that pass light over
420nm quite efficiently. The large monochrome panels work with the efficient
460nm LED's that are also more efficient and far lower cost than 400-410nm
LED's. If you compare pricing and efficiency of 400-410nm LED's you'll see that
they are more expensive and far less efficient than ~460nm blue LED's. You get
much more bang for the buck at 460nm.

Small LED and Pico projectors use three LED's as their light source. A Red
(635nm), Green (530nm) and Blue (460nm). They also work well with resins that
cure at over 460nm. To make them even more efficient the green and red LED's
may be swapped with blue LED's so that all three LED's are used for curing.

We have been using LCD's for lithography for several years along with resins
that cure at over 420nm.
http://bucktownpolymers.com/zve200-v470.html is just one of many available.
Bucktown Polymers made them available so that standard off the shelf LCD panels
and LCD projectors may be used for lithography with no to little modifications.
The only modifications to the projectors are to the lenses to make them focus
closer than 1 meter. Over a hundred radcure formulas are available for lithography and
most may be made to cure to well above 500nm.

TechnoJLL
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Re: LCD Based 3D Printer - Introduction

Postby TechnoJLL » Sat Sep 05, 2015 2:07 am



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