<p>If what Thomas Sanladerer states is correct, the Mars 2 Pro (monochrome LCD, no color filter) has a layer time approximately 1/3 as long as the Mars/Pro printers (where color LCDs are used):</p>
<p><div class="youtube-embed"><div>
                <iframe width="640px" height="395px" src="https://www.youtube.com/embed/0yZ4KiK_pl0?start=0"></iframe>
            </div></div></p>
<p>This would indicate that the light passing through the LCD, when the color filter is present, is 1/3. Put it in other words, only ONE subpixel is capable of transmitting UV light.</p>
<p>Consequently, using all of them would not improve resolution because the other subpixels are always opaque.</p>

CC BY-SA 4.0
2020-12-14T20:38:55.150Z
2020-12-14T20:38:55.150Z
FarO
<p>It should be as simple as using a monochrome LCD.  You don't actually want any color filters to interfere with the UV light.</p>

<p>Do we know that LCD printers are not using monochrome LCD panels?  It always seemed so obvious that I assumed it was the practice.  All you need are the front and back polarizer layer and the LCD itself to rotate the light.</p>

CC BY-SA 4.0
2019-07-22T18:23:41.710Z
"Do we know that LCD printers are not using monochrome LCD panels?" That's the question. Resolution wise, they look like repurposed smartphone color panels (i.e. front and back polarizer layer and the lcd).
Nobody
CC BY-SA 4.0
2019-07-22T18:53:01.833Z
The Wanhao Duplicator 7 apparently uses the LS055R1SX03 LCD which is an RGB LCD. These are obviously repurposed smartphone LCDs. There is very little demand for monochrome high-resolution LCDs so they would probably be prohibitively expensive (if available at all).
Tom van der Zanden
CC BY-SA 4.0
2019-07-22T19:32:37.237Z
I agree that demand is low.  Making anything in low volume is expensive unless you can piggy-back on the key tech.  That said, some modifications are less costly than others.  It is possible that a run of a few thousand panels could be done without the filter layer, or, perhaps more likely, with the filter layer but without colorants in the filter layer.  The Alibaba site offers to ship the LS055R1SX03 LCD without a backlight specifically for resin 3D printers, but say nothing about the filter layer.  It may be that all three colors are similarly transmissive of UV light.  Only testing tells.
cmm
CC BY-SA 4.0
2019-07-22T20:09:21.907Z
@TomvanderZanden That's the printer I own (well, plus version). :) Thanks, I will definitely try to make use of the subpixels then. I guess it's possible (even likely) that  it would be sufficient to just use color .png instead of monochrome .png (i.e. the borders of white areas would appear in funny colors). That and a microscope to figure out the subpixel arrangement. Could probably use an existing slicer without modification by increasing the resolution there and then converting the output image files with a simple script.
Nobody
CC BY-SA 4.0
2020-12-14T20:35:22.803Z
Different colors transmit UV differently. It may even be that only the blue color is transmissive and the other ones always opaque, even when theoretically ON. Using subpixels would require different exposure time and difficult or impossible calibration.
FarO
CC BY-SA 4.0
2019-07-22T17:54:39.317Z
2019-07-22T17:54:39.317Z
cmm
<p>The LCD resin printers I've looked at have pretty standard resolutions like for a smartphone and I understand they use the same technology. However, color LCD screens have three RGB sub-pixels for each color pixel. Check for example this magnified picture of an S-IPS LCD screen:
<a href="https://i.sstatic.net/bml7t.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/bml7t.jpg" alt="enter image description here"></a>
It seems like they could just omit the color filter and have three grayscale pixels for each color pixel.</p>

<p>3D printing just uses one color - UV. So why don't they have resolutions that are multiples of three of the usual resolutions?</p>

<p>All results about sub-pixels that I could find are about anti-aliasing, which is different (using the existing pixels better vs. having more pixels).</p>

CC BY-SA 4.0
2019-07-21T01:36:44.710Z
(As a reply on a now self deleted comment) I think that the OP is asking about LCD resin printers.
Mick
CC BY-SA 4.0
2019-07-22T09:23:36.077Z
@Mick That is correct.
Nobody
CC BY-SA 4.0
2019-07-22T16:20:52.857Z
Too speculative to be an answer: Probably because nobody has thought of doing this before. Or maybe people are doing it and we don't know about it? I can't think of any reason why it wouldn't work. As a side note, the resolution would only be tripled in one direction.
Tom van der Zanden
CC BY-SA 4.0
2019-07-22T16:32:55.783Z
@TomvanderZanden I can hardly believe this, but if so, then I would be glad to triple the amount of pixels on mine. :D And yes, it's only tripled in one direction. And it also depends on the subpixel layout how the resolution would be increased exactly.
Nobody
CC BY-SA 4.0
2019-07-22T21:37:32.013Z
I just realized it's possible they use smartphone panels *including* the color filters. Then the blue sub pixels would provide most of the light and the other sub pixels would be useless.
Nobody
CC BY-SA 4.0
2019-12-20T13:03:42.137Z
Why adding complexity (handling each subpixel) when the quality attainable would not significantly improve (the resin printing has limits), but more expensive electronics would be required to process the data?
FarO
CC BY-SA 4.0
2019-12-20T17:11:37.817Z
@FarO It's possible in theory that the current resolutions are already at the maximum that makes sense (citation needed, personally I doubt it), but the electronics are exactly the same. It's not like 3D printing is a high-bandwidth application, any lcd driver which can display 1fps of greyscale can do the same for color.
Nobody
CC BY-SA 4.0
2019-12-21T19:23:26.357Z
@Nobody ok but the CPU has to handle them. The current LCDs have about 3.7 Mpx, splitting by three would mean 11 Mpx per frame. It could be that the additional resolution achieved is not worth the expense, especially now when the current DLP printers already improve resolution over FDM by a large margin
FarO
<dlp><resin><lcd-screen>
Why don't LCD printers use subpixels in color panels?
Nobody
# Why don't LCD printers use subpixels in color panels?

(Asked by: username_0 on 2019-07-20)

The LCD resin printers I've looked at have pretty standard resolutions like for a smartphone and I understand they use the same technology. However, color LCD screens have three RGB sub-pixels for each color pixel. Check for example this magnified picture of an S-IPS LCD screen:
[![enter image description here](https://i.sstatic.net/bml7t.jpg)](https://i.sstatic.net/bml7t.jpg)
It seems like they could just omit the color filter and have three grayscale pixels for each color pixel.

3D printing just uses one color - UV. So why don't they have resolutions that are multiples of three of the usual resolutions?

All results about sub-pixels that I could find are about anti-aliasing, which is different (using the existing pixels better vs. having more pixels).

**Tags:** dlp, resin, lcd-screen

> **Comments:**
> **username_1**: (As a reply on a now self deleted comment) I think that the OP is asking about LCD resin printers.  
> **username_0**: @username_1 That is correct.  
> **username_2**: Too speculative to be an answer: Probably because username_0 has thought of doing this before. Or maybe people are doing it and we don't know about it? I can't think of any reason why it wouldn't work. As a side note, the resolution would only be tripled in one direction.  
> **username_0**: @username_2 I can hardly believe this, but if so, then I would be glad to triple the amount of pixels on mine. :D And yes, it's only tripled in one direction. And it also depends on the subpixel layout how the resolution would be increased exactly.  
> **username_0**: I just realized it's possible they use smartphone panels *including* the color filters. Then the blue sub pixels would provide most of the light and the other sub pixels would be useless.  
> **username_3**: Why adding complexity (handling each subpixel) when the quality attainable would not significantly improve (the resin printing has limits), but more expensive electronics would be required to process the data?  
> **username_0**: @username_3 It's possible in theory that the current resolutions are already at the maximum that makes sense (citation needed, personally I doubt it), but the electronics are exactly the same. It's not like 3D printing is a high-bandwidth application, any lcd driver which can display 1fps of greyscale can do the same for color.  
> **username_3**: @username_0 ok but the CPU has to handle them. The current LCDs have about 3.7 Mpx, splitting by three would mean 11 Mpx per frame. It could be that the additional resolution achieved is not worth the expense, especially now when the current DLP printers already improve resolution over FDM by a large margin  

---

## 2 answers

### Answer by username_3 on 2020-12-14. Score: 1

If what Thomas Sanladerer states is correct, the Mars 2 Pro (monochrome LCD, no color filter) has a layer time approximately 1/3 as long as the Mars/Pro printers (where color LCDs are used):

This would indicate that the light passing through the LCD, when the color filter is present, is 1/3. Put it in other words, only ONE subpixel is capable of transmitting UV light.

Consequently, using all of them would not improve resolution because the other subpixels are always opaque.


---

### Answer by username_4 on 2019-07-22. Score: 0

It should be as simple as using a monochrome LCD. You don't actually want any color filters to interfere with the UV light.

Do we know that LCD printers are not using monochrome LCD panels? It always seemed so obvious that I assumed it was the practice. All you need are the front and back polarizer layer and the LCD itself to rotate the light.

> **Comments:**
> **username_0**: "Do we know that LCD printers are not using monochrome LCD panels?" That's the question. Resolution wise, they look like repurposed smartphone color panels (i.e. front and back polarizer layer and the lcd).  
> **username_2**: The Wanhao Duplicator 7 apparently uses the LS055R1SX03 LCD which is an RGB LCD. These are obviously repurposed smartphone LCDs. There is very little demand for monochrome high-resolution LCDs so they would probably be prohibitively expensive (if available at all).  
> **username_4**: I agree that demand is low.  Making anything in low volume is expensive unless you can piggy-back on the key tech.  That said, some modifications are less costly than others.  It is possible that a run of a few thousand panels could be done without the filter layer, or, perhaps more likely, with the filter layer but without colorants in the filter layer.  The Alibaba site offers to ship the LS055R1SX03 LCD without a backlight specifically for resin 3D printers, but say nothing about the filter layer.  It may be that all three colors are similarly transmissive of UV light.  Only testing tells.  
> **username_0**: @username_2 That's the printer I own (well, plus version). :) Thanks, I will definitely try to make use of the subpixels then. I guess it's possible (even likely) that  it would be sufficient to just use color .png instead of monochrome .png (i.e. the borders of white areas would appear in funny colors). That and a microscope to figure out the subpixel arrangement. Could probably use an existing slicer without modification by increasing the resolution there and then converting the output image files with a simple script.  
> **username_3**: Different colors transmit UV differently. It may even be that only the blue color is transmissive and the other ones always opaque, even when theoretically ON. Using subpixels would require different exposure time and difficult or impossible calibration.  

---

