Prototyping PCB using LCD


Proximity Photomask Stereo-lithography
Just to share results of a project into using LCD display to expose photo sensitive coated PCB and also coating PCB's with 3D printer resin as a photo etch resist in the same way SLA 3D printers work. 
UV back-light we reviewed our existing UV exposure box that uses UV tubes and also making our own UV Led panel.

There are some good disucssion related to this topic on build your own sla



Background references
  • Bungard PCB UV sensitive characteristics350-450 nm
  • LCD Panel UV filter characteristics: 405-410 nm.  Some specs mention 410 and higher are not filtered. A high resolution and large working area is possible  with the 4K TN panels. This means, theoretically that with a resolution of 3840 × 2160 on a a 24" panel, then that is 183.58 PPI or 183.58 per 2.54 centimeter. Then each pixel is 25.4 mm / 183.58 = 0.138 microns. 
  • UV LightBox characteristics UV florescent tubes typically 350 - 400nm 
  • 3D Printer Resin UV curing characteristic:UV up to 440nm. The higher up in the UV spectrum the slower curing time, but at 410nm it's possible to cure a 1mm blob of resin in 8 seconds. 
  • UV LED characteristics:395 - 410nm . You can see in the diagram there is a very narrow peak wavelength. If LCD is really 405-410nm  then power of the LED's are being filtered out. 
  • Blue LED's: normally around 465-468nm 
  • Violet 10W LED: 410-420 nm



LED Sources:
  • http://www.leds.de/High-Power-LEDs/Nichia-High-Power-LEDs/Nichia-SMD-LED-UV-NCSU033B.html
  • http://www.leds.de/High-Power-LEDs/Seoul-Z-LED-Acriche/Seoul-Z-Power-LED-P4-emitter-white-240lm-mit-Platine-Star.html?force_sid=533e216a28dc5632e242630f376b378b
  • https://futureeden.co.uk/collections/violet

Light Box Ideas

I liked the idea of having both UV and RED leds in the lightbox as it allows you to align the PCB to the image using the red LED's before exposing with UV
  • http://www.electronics-lab.com/project/led-uv-exposure-box/
  • https://www.youtube.com/watch?v=loTTcav1v88

Some main challenges:
  • The UV Lightbox wavelength is being filtered by the LCD display, so no curing of resin and does not expose  UV sensitive PCB material 
  • the blue LED's seem to cure the UV resin but no expose the Burgard UV sensitive PCB


LCD displays:

At 2048x1536 Resolution on a 9.5" " display, the pixels are not visible, so that's the optimum resolution to have. Some makers are considering using 4K screens with even higher resolutions: http://www.ebay.com/itm/192183822490

9.7" Retina TFT-LCD Display - LP097QX2
  • Sources:
  • http://www.pollin.de/shop/dt/MTQ5ODc4OTk-/Bauelemente_Bauteile/Aktive_Bauelemente/Displays/20_3_cm_8_Display_Set_mit_Touchscreen_LS_8T_HDMI_DVI_VGA_CVBS.html
  • https://www.aliexpress.com/item/7-Inches-1024-600-IPS-Screen-Display-LCD-TFT-Monitor-EJ070NA-01J-with-Remote-Driver-Control/32789092996.html?
  • spm=2114.13010208.99999999.288.H2cnte
  • http://www.lcd-parts.com/polarizer.aspx
  • http://cdn.intechopen.com/pdfs-wm/6601.pdf
  • https://de.aliexpress.com/item/9-7-Inch-2048x1536-IPS-2K-Retina-Monitor-Screen-LCD-Module-HDMI-TV-Portable-Raspberry-Pi/32771305252.html?spm=2114.13010208.99999999.262.5yAcKb



LED's
  • https://www.aliexpress.com/item/10-pcs-lot-45-60-90-100-Degree-13mm-Mini-LED-PCB-Angle-Lens-for-IR/32463089165.html?spm=2114.13010608.0.0.5psJTK
  • https://plus.google.com/b/116967575537221869898/118056272494296302181/posts/KsSetrBowqQ
  • https://www.aliexpress.com/item/20Pcs-Lot-Light-Beads-EPILEDS-45-Mil-Led-Chips-390nm-400nm-440nm-450nm-3W-Led-Diode/32794086679.html?spm=2114.01010208.3.16.FGf1JY&ws_ab_test=searchweb0_0,searchweb201602_2_10152_5010012_10065_10151_10068_10136_10137_10157_10060_10138_10155_10062_10156_437_10154_10056_10055_10054_10059_303_100031_10099_10103_10102_10101_10096_10147_10052_10053_10107_10050_10142_10051_5020013_10084_10083_10080_10082_10081_10177_10110_519_10111_10112_10113_10114_10180_10182_10185_10184_10078_10079_10077_10073_10186_10123_142-10051,searchweb201603_2,ppcSwitch_7&btsid=4e1a1d00-2f34-4e45-8a48-f068c45adeca&algo_expid=0d7ad8d4-eed1-4d44-8f21-aeb92b1a4040-2&algo_pvid=0d7ad8d4-eed1-4d44-8f21-aeb92b1a4040


Control boards for retina displays:
Retina Display Controller Board - DE2KTOP Air


References:
  • Example of using LCD as photo mask:
    • https://www.youtube.com/watch?v=hczjN9er9TI
Example of using SLA resin 
  • https://www.youtube.com/watch?v=vxl7glJMKOQ&t=19s
Others
  • OpenSLA - Build Your Own SLA Resin 3D Printer
  • http://www.buildyourownsla.com/forum/viewtopic.php?t=2113&start=60
  • DesignTool: https://easyeda.com/
  • PCB Manuafacture:https://easyeda.com/order
  • LCD display source: http://www.ebay.de/itm/BN-9-7-RETINA-DISPLAY-SCREEN-APPLE-iPAD-3-4-LIKE-LG-PHILIPS-LP097QX1-SP-A1-/161975309619?hash=item25b67b1533:g:v1sAAOSw~OVWvKli
  • http://www.aspe.net/publications/Annual_2006/posters/1equip/5mems/1988.pdf
  
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