OLED subpixels. How do they work?

Cyber · 24 January 2022 14:36

Right, so it should fetch a higher resale value if you sell it to buy that new TV! Lol

I could be wrong but weren’t older (or at least some) LG OLED panels WOLED with WRGB layout with all white OLEDs in the back layer shining through an RGB filter as described here? If so, then one of those models might be a nice alternative except that they most definitely won’t have 120hz input and BFI.

What’s the difference between RGB, RGBW, and WRGB pixels?

This explains something @Nesguy has been saying for a while concerning RGBW subpixel arrangements.

This debunks the above at least on some models of higher end LG OLED TVs. Saying basically that there’s no compromise on the total number of pixels with the addition of the white subpixel.

It also says that RGBW is also being used on some LG Display IPS LED panels as well and that there’s another inferior type which shares one white subpixel per pixel.

Good information to add to the subpixel arrangements trove.

LG 4K LCD TVS CONTINUE CONTROVERSIAL RGBW TECH

c9f5fdda06 · 24 January 2022 14:36

WRGB means a pixel has a white back-pixel (W) and then the three sub-pixels on top of it (RGB). OLEDs use this.

RGBW is a cost saving layout of sub-pixels. It is 4 sub-pixels in one pixel, not 3. Red, Green, Blue, White. It helps increase the brightness but almost in all cases it prevents a tv from truly reaching 4K resolution.

nvm

@Nesguy @guest.r @hunterk

hunterk · 24 January 2022 14:36

according to rtings, the CX’s subpixels look like this (though apparently all 4 of them are never lit all at once; I don’t know how that’s supposed to work):

This is a composite of the 2 subpixel images they provide to show all of them at once.

Cyber · 24 January 2022 14:36

This might not be correct. Can you verify this? If anything it would have been the older models which used WRGB, while the newer models use RGBW.

This also goes along with what I remember reading about the WOLED technology around the B6, E6 era. They used to say that LG’s patented technology used all white OLEDs with an RGB colour filter to overcome the issue of uneven wear of different coloured OLEDs.

Over time I noticed the story changed a bit but it would be interesting to look up the different patents and see what’s in there. There’s also a publication available called https://www.oled-info.com/ that tracks the development of the industry and technology.

With that said according to the hdguru article, LG has 2 types of RGBW, one with an additional white subpixel pixel for each pixel and one with a shared white subpixel for every 2 pixels.

Since C9 is newer it probably uses RGBW.

The technology LG uses was originally developed by Kodak and it was called Color-by-White. It uses white OLEDs with an RGB colour filter.

https://www.quora.com/Why-doesnt-Samsung-make-OLED-TVs-to-compete-with-LG-Why-does-Samsung-reserve-OLED-just-for-phones/answer/Bob-Myers-5?ch=10&oid=252540963&share=df5e4c44&srid=ueYXP&target_type=answer

Kodak Color by White OLED Technology

Some of them couldn’t even tell my old presets running on a projector were shaders. Lol

c9f5fdda06 · 24 January 2022 14:36

I admit I’m still learning myself but here’s a video (spanish but the pictures speak for themselves; later on he shows difference WRGB and RGBW) that sheds some light.

Aléjate de RGBW y su Falso 4k | Estructura de Pixeles RGB RGBW WRGB OLED - YouTube

(“Get away from RGBW and fake 4K. Pixel structures…”)

Cyber · 24 January 2022 14:36

I don’t think you’re fully understanding what they’re saying in all of the articles. In the HDGURU article, it is reported that LG said that their more expensive TV’s which use RGBW have an additional white subpixel for each pixel in their more expensive TVs. It is also reported that they have RGBW panels that feature a shared white subpixel for every pixel. The more expensive ones with the additional white subpixel can definitely have the full 3840 x 2160 pixels.

This is one of the same articles I posted above though.

c9f5fdda06 · 24 January 2022 23:58

eh, that’s actually what I’m getting at – sorry if I wasn’t clear. Each pixel for OLED WRGB has 4 subpixels. The RGBW has a single pixel that includes RGB subpixels next to a pixel that is pure white. This reduces the resolution.

RGB

A TV screen is actually a grid that’s made up of a fixed number of pixels per resolution. A 4K screen is 3,840 pixels high and 2,160 pixel wide, for example. In total, this numbers of 8 million pixels. An RGB television fills this grid with rows that consist of 3 pixel colors: red, green, and blue. These rows are repeated until the entire screen is filled. Because each pixel produces a color, the color representation is sharp and realistic.

RGBW

With a RGBW screen, each row of 3 colored pixels is alternated with a white pixel. This means that 25% of the screen isn’t made up of color, but of white light. If you exclude all of these white pixels, the television actually has a resolution of 2,880 by 2,160 pixels. This results in a less realistic color representation and less sharp screen, compared to an RGB television.

WRGB

An OLED screen features its own pixel structure, called WRGB. Instead of utilizing rows of different pixels, like RGBW, each pixel is identical. These pixels can independently produce color and white light. This is possible because each pixel consists of red, green, blue, and white sub pixels stacked on top of each other. With help of a filter, only the desired colors are shown. This technology helps ensure an extra accurate color representation.

Cyber · 24 January 2022 14:36

This is not my interpretation based on my research of the original WOLED technology. I would have to do some more research but my current interpretation is that WRGB OLED Technology uses the white OLEDs like a backlight together with a regular RGB subpixel arrangement colour filter. RGBW OLED uses this same arrangement plus adds another adjacent white OLED subpixel to assist with brightness and to lessen wear on the other white OLED subpixels.

I suggest you read up on the original Kodak Patents and technology which LG Display now owns and they will have all of the correct answers.

I’ll stop here for now since I don’t want to detract from the topic any further.

Nesguy · 24 January 2022 14:36

The last 7 posts or so should be split into a new topic IMO, it’s a valuable discussion but it’s getting off topic for the thread

@hunterk

Cyber · 12 February 2022 11:13

Cyber · 27 April 2023 14:20

Here are some macro shots of Wii Sports running on an LG 55OLEDE6P using CyberLab Mega Bezel Death To Pixels Shader Preset Pack.

The first ones are using CyberLab Wii, which uses Mask 6 at size 2, while the others use Mask 7 and 8 at different sizes.

The last set uses Mask 6 size 2 with aperture grille layout followed by Mask 7 and 8 at various sizes.

This could be the final verdict on the accuracy and capability of WOLED TVs to depict RGB phosphor triad emulation properly.

So far it doesn’t seem like they can. However this doesn’t mean that WOLED TVs aren’t exceptional at displaying my shader presets because at normal viewing distances they are the best I’ve ever seen.

My experience though is limited to a 4K IPS TV that can only display YCbCr 4:2:0 colour at 60Hz and a 1080p VA TV that can display RGB 4:4:4.

All three do a decent job in its own way and each of them has its shortcomings.

I know the pics aren’t properly labeled. I’ll try to do that when I get a chance.

So it’s quite possible that the best TV to use with my presets might be a 4K IPS or QLED/Neo QNED with MiniLED Full Array backlight and as many dimming zones as possible to minimize blooming.

Dual Layer seems to be dead on arrival as Hisense can’t get the main and backlight control panel synchronization tight enough while WOLED also suffers from sub-optimal subpixel layout.

Too bad no one seems to have one of those shiny new MiniLED QDLED/IPS TVs to share there experience so far.

I’ve also heard that some of the newer Samsung TVs (could be MiniLED, I’ll have to confirm) are having some severe issues with their auto dimming algorithms.

20220705_171317

20220705_192725

20220705_192410

20220705_192957

Sonic The Hedgehog Sega Logo, White Background

Mask 6, Size 1

Sony Megatron CVM SDR

Apparently not all WOLED (RGBW) TV’s subpixels are the same after all. From the 2018 models, LG Display increased the size of the red subpixel by 80% as a burn-in reduction feature.