Monday, November 1, 2010

Samsung Omnia 7 uses a PenTile AMOLED display

A reader recently asked if the Samsung Omnia 7's Super AMOLED screen is a PenTile Matrix one. I've always suspected it was (I said so in my impressions), as all of Samsung's 480x800 4" AMOLED screen in existence uses PenTile technology (correct me if I am wrong).

PenTile Matrix is subpixel technology and apparently allows Samsung to increase the production yield of OLED displays (blue OLED pixels are difficult to produce). This is because PenTile has two subpixels per pixel where as a traditional RGB stripe has three subpixels per pixel, allowing for 33% less subpixels. Fewer pixels to make = higher yield.

Samsung claims that PenTile does not affect the screen quality but I disagree. Texts looks blurry, especially if viewed with small fonts, due to the unusual subpixel arrangement. Individual pixels are also visible despite the high pixel density of the screen. Dithering is also a common issue I found with viewing AMOLED devices with PenTile subpixels.

Below is a close up of the Samsung Omnia 7's screen. You can clearly see the pixel arrangement and how it may affect the display's legibility.

Medium size font

Small font

If you want high contrast and colour saturation, there is nothing wrong with an AMOLED display. However if your priority is sharpness and colour accuracy, get one with a traditonal LCD (or Super LCD) with RGB stripe. Unfortunately I do not know if there are any 480x800 AMOLED display in production with a traditional RGB stripe.

11 comments:

Joel said...

How can you say that this text is not sharp? You can,for example, see single pixel white spaces at the top of the "m". What you may see is pattern visibility,but your image is evidence enough of the sharpness of the PenTile text rendering.

Joel said...

How can you say that this text is not sharp? You can,for example, see single pixel white spaces at the top of the "m". What you may see is pattern visibility,but your image is evidence enough of the sharpness of the PenTile text rendering.

Jon said...

Well yes, that's because the font I was using was a medium size one.

Updated the post with a image of the default font size in Internet Explorer.

Joel said...

The font strokes are one pixel wide as can be readily seen in your very crisp photo. RGB stripe would not have shown the definition at the top of the m and better than PenTile. Try this for yourself and see. I feel that you are seeing PenTile's pattern visibility by viewing it at a distance it was not designed for, but are not seeing a lack of sharpness as is defined by the ability to modulate lines and spaces.

Alan said...

I have to agree with Jon. I have a Desire with a Pentile OLED screen and my wife have one with a Sony SLCD. The OLED has stunning contrast and colour, but the SLCD is sharper. The resolution appears higher as well, and the pixels are not visible unlike the OLED Desire.

Mikael said...

Thanks for the pictures, Jon.

Personally, I would take the sharpness of the SLCD before the contrast of the SAMOLED. The fuzzy text is too annoying to read.

Hope Samsung will find a way to reach SAMOLED contrasts without PenTile.

Joel said...

Can I ask you Jon how you generated the smaller font? The smaller text appears quite different than the medium text. As this is an Omnia 7 is it possible that you are using some sort of ClearType feature with this font? If so,try turning this off to reduce the amount of anti-aliasing that appears in that font.

Jon said...

There isn't a Clear Type setting on the Omnia 7 (not that I know of). The small text is on Internet Explorer. Everything is on default. No trickery involved. :)

Joel said...

No, please don't take my comment wrong. I was not implying trickery. My comment is that this is how PenTile looks when ClearType is turned on for such small fonts, but I am not familiar enough with Windows Phone 7 to know if ClearType is turned on by default. It would be good if someone could figure out how to turn that off.

Jon said...

No worries. :)

I also wish that there was an option to turn off cleartype. AFAIK clear type was designed for traditional RGB stripe, so having it enabled on a PenTile display is rather silly.

Alas, I didn't see any options to enable/disable it. Times like this I love the access to registry on the old Windows Mobile OS.

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