All posts tagged Tablet

Response to Tested Blog – A Review by W. Fenlon

On June 9th Wesley Fenlon posted an article at Tested “How PenTile Displays Are Brighter But Not Always Better.” This article was in some ways even more difficult to follow than the one we recently struggled to translate from Russian.  The biggest part of the confusion was between PenTile RGBG OLED and PenTile RGBW LCDs as well as the unrelated diversion into metal oxide backplane technology.

Let me begin by differentiating these two implementations of PenTile technology:


  • Value proposition:  enables OLED to achieve higher resolution with equivalent brightness
  • How accomplished:  eliminating one-third of the subpixels reallocates the dead space around each subpixel into useful luminous areas, reducing current density and allowing high resolution panels to appear as bright as lower resolution panels without lifetime degradation.
  • PenTile algorithms:  subpixel rendering SPR, edge sharpening


  • Value proposition:  improves transmissivity of the LCD
  • How accomplished:
  1. Adding a clear subpixel to pass white light from backlight without significant attenuation
  2. Eliminating one-third of the subpixels allows each subpixel to be one-third wider and have better aperture ratio
  3. Using dynamic backlight control (DBLC) allows images to be analyzed to add global dimming, to reduce power to the backlight , while preserving the color of high luminance saturated colors and at the same time increasing the contrast.
  • PenTile algorithms:  RGB to RGBW gamut mapping, subpixel rendering SPR, edge sharpening , image analysis for dynamic backlight control

Let me add another clarification:  RGB stripe can be used in both OLED and LCD.  PenTile can be used in both OLED and LCD.  Wesley confuses things by comparing a PenTile RGBW LCD to a RGB stripe OLED like the Samsung 4.5-inch Super AMOLED Plus

So Wesley had it right when he said that the PenTile RGBW used in the WQXGA panel had a fourth subpixel (clear or white) to let more light through, “making the screen brighter as it consumes less power”.  He also had it right when he said that”… backlight dimming for darker images, the 2560 x 1600 PenTile display clearly has an advantage in power efficiency…”

Wesley says that “PenTile screens have fewer subpixels overall than RGB (stripe) LCD arrays.  The pixels are also bigger, which means screens for these display(s) often have to be slightly larger than (RGB stripe) LCDs, hence that 4.5” Super AMOLED Plus on the Samsung Infuse…”   Let me correct and clarify this.  It is true that for a given diagonal size that the subpixels are larger, than the equivalent RGB stripe panel, however the pixels are equivalent.  PenTile displays use logical pixels that contain varying numbers of subpixels with luminance centers equivalent to an RGB stripe panel.  RGB stripe displays are comprised of pixels that each have 3 subpixels and are always the same size.  This is true for both LCD and OLED.  Having fewer and larger subpixels does not cause image quality issues that were supposedly illustrated with pictures in Wesley’s blog and have previously appeared in other blogs.  Shown below are images that I took myself from an RGB stripe display and from a PenTile RGBW display.  You will see that PenTile images with equivalent number of pixels (not subpixels) as RGB stripe do not suffer from blurriness or lack of crispness (note that some small amount of aliasing/moire on both images is due to the digital nature of such image capture). I did nothing in Photoshop to change the quality of either image other than equivalent scaling to fit the format needed for the blog.  In a future blog I will show such a comparison of B&W text to illustrate again that such text is not degraded by PenTile


My photo of a PenTile RGBW LCD

My photo of an RGB Stripe LCD



Samsung has offered WVGA 4.3-inch and 4.5-inch diagonal AMOLED.  These are RGB stripe LCDs.  Samsung offers WVGA AMOLED that are 4.1-inch and smaller that are PenTile OLED.  The reason that PenTile is not offered in these larger sizes is that it would exhibit pattern visibility at such a low dpi and offers less value to these OLED designs.  If however OLED were needed in high dpi at these larger diagonal sizes thenPenTile OLED would again have utility.

In the final paragraph of Wesley’s blog he states that “…the RGBW layout, (for) the 2560 x 1600 PenTile does seem to be employing that same improvement…”  I am not entirely clear which improvement he is referencing, but since it follows the reference to the Super AMOLED Plus, I think he means the use of RGB stripe.  It is true that the 2560 x 1600 panel does not use RGB stripe, but it also is not AMOLED.  The reason it does not use RGB stripe is that an amorphous silicon TFT backplane at 300 dpi with today’s state of the art technology would have about a 30% aperture ratio, making it impractical for power consumption for a table application.  Perhaps LTPS or metal oxide transitors might improve this aperture ratio, but uniformity of these technologies for 10.1-inch diagonal has yet to be demonstrated in production.  Once that technology is proven for this diagonal, it may allow practical tablet applications, but at that point PenTile technology could again be applied for an additional 40% improvement in power efficiency.  When comes to saving power, saving more power is always better.  I like to say that people are never too thin or too rich and likewise panels never save too much power.

One other small point is that this WQXGA demonstration panel already has a very wide viewing angle technology that is very similar in performance to IPS.  PenTile can be combined with any WVA technology for wide viewing angle performance equivalent to that seen on an RGB stripe panel.

To conclude

  • PenTile technology does not create blurry images or black and white text.
  • PenTile RGBW LCDs are more power efficient than any other technology in the market.
  • PenTile RGBW LCDs can be combined with IPS or any other wide viewing technology.
  • PenTile RGBW LCDs are fit for use on tablets due to the demands for high resolution and low power consumption.

OneIndia Video Post

There was some terrific video coverage of the new Samsung WQXGA, PenTile RGBW 300 dpi tablet panel that was shown at the recent SID DisplayWeek.

While this video mentions other high resolution tablets, no company, other than Samsung, has publicly demonstrated any 10.1-inch prototypes of more than 150 dpi to date.

This video raises lots of interesting questions about the application of this panel to products, but, as I have already said, Samsung is still in the prototype stage of product development  so you will not see any tablets with PenTile RGBW 300 dpi within this year.

Will RGBW help with a checkerboard pattern

The ability to observe pattern visibility is a function of visual acuity in cycles/degree of human vision and the size the pattern.  A person with the ability can see such a checkerboard pattern in a 4-inch WVGA pattern from normal viewing distance can also see stripe patterns on many popular RGB stripe panels being sold today.  For an RGBW panel the checkerboard pattern at the lower dpi range of PenTile OLED applications is only visible for fully saturated green or red on black. With an RGBW panel at any lesser color saturation the blacks in the checkerboard are filled in with the white subpixels to improve the brightness and to reduce this effect.

At 300 dpi on a tablet panel, which is typically viewed from 50% further away, about 18 inches, even the most saturated red and green on black as the worst case condition will not have any apparent checkerboard since the ability to resolve this will require vision of nearly 50 cycles/degree.  Few of us have vision which is that good.

So that brings me to the comment on zooming in to see text that is less clear.  First of all, your eyes do not have a zoom feature.  At least mine don’t.  These panels are designed to be viewed at a certain distance.  It is like saying that a tapestry when zoomed in shows the artifact of the stitches, or that a half tone print when zoomed in shows dots.  Of course they do, but that is not how they are used.  Secondly, if you do zoom in on black and white text, you will see the same detail in even single stroke fonts for PenTile as you do for RGB stripe.  Examples that have been shown in one recent blog say that it makes it look less sharp, but these images show otherwise.  Look at the black spot at the top of the “n”, where the curve meets the straight stem in the RGB stripe and compare that to PenTile. If it were less than sharp that single pixel black dot would not be there.

Single pixel dot at top of PenTile "n" is equal to RGB stripe


Gizmodo’s ‘Super Clear Displays of the Future’

“The iPhone 4′s beautiful Retina Display is a little less beautiful today. Why? Because at SID 2011, an exhibition about displays, companies have revealed screens that were transparent, tablets that did glasses-less 3D and screens clearer than Apple’s fabled Retina.

Here are the coolest screens from SID 2011:
Samsung 10.1-inch 300ppi display: A display that’s been heard from before, the Samsung 10.1-inch, 2560×1600 display has a pixel density of 300ppi. Which is killer on such a big screen (iPhone’s Retina Display is 326ppi across 3.5inches). The panel uses PenTile RGBW technology (which didn’t do so hot in the Nexus One) but promises to make colors pop and consume 40 percent less power. In any case, it’s still a freaking 10-inch retina display.”

Absolutely thrilled to be featured on Gizmodo’s roundup of the coolest screens from SID 2011.
Thanks for that!

Day 1: SID recap

Visitors to the PenTile SID demonstrations at SID

Day 1 at SID is behind us and we’re pleased to say we had an incredibly busy day. The Samsung/Nouvoyance demonstrations were mobbed, almost to the point that it was difficult to walk through virtually all day. The demos of the new WQXGA 10.1″ tablet display, as well as those for the multiprimary PenTile displays, performed stunningly.  We were glad to see some tech industry experts, including some folks from Engadget, come through and take a tour of the new tablet display.

But we were also pleased to see that the PenTile multiprimary display demonstration got a bigger crowd throughout the day. We are encouraged that this means good things to come for our entire line of PenTile displays.

Demonstration of PenTile Multiprimary Display

Thanks to all who stopped by yesterday. If you’re in the neighborhood of SID, stop by our booth #707 and see the displays for yourself!

Engadget video review: 10.1″ PenTile WQXGA Tablet Display

Live from the SID 2011 show floor, check out one of the first reviews of the PenTile WQXGA tablet display, courtesy of Engadget. The video shows “why you should join the RBGW revolution” (their words, not ours).

Engadget preview of PenTile WQXGA Tablet display:

300 dpi is Fine but I Would Rather Have IPS

This is not an “either/ or” condition. This a case of having your cake and eating it too. PenTile RGBW technology is perfectly compatible with all types of wide viewing angle technology such as IPS, multidomain (PVA, MVA, etc). In fact, as a power saver it makes it a bit easier to use a wide viewing angle (WVA) technology with PenTile RGBW since many of these WVA techniques reduce light throughput.

IPS (in plane switching) was the name given to a type of WVA technology many years ago by Hitachi and was licensed to other display makers. Other variants of this methodology are in use by Samsung. Samsung uses a few different types of WVA technologies depending upon the application.

Perhaps there are some who are still asking, “Does a tablet PC that is being used by one person who is looking directly at the display really need WVA technology?”. The answer is a definite yes it does. Even a mobile display is used laying on the desk in front of you or held in your hands. Then consider viewing in both portrait or landscape modes and you realize that WVA capability is a generally a good idea.

So, here is the interesting thing about the new Samsung WQXGA PenTile RGBW prototype panel–it has a very wide viewing angle technology, not so different from IPS. Judge for yourself when you come see this at SID Display Week in LA this week.

What to Expect from Us at SID

While PenTile is generally associated with mobile products, where customers have seen all of our current design-ins, we have been applying the technology to larger sizes as well.

At Display Week 2011 in Los Angeles, along with Samsung, we will demonstrate new technology for two applications…

  1. A 10.1” tablet demo using PenTile RGBW LCD, with the highest resolution ever made
    It runs at 55% of the power of an equivalent RGB stripe display and enables a thin and light tablet without sacrificing ultra-high resolution. This tablet is about the same pixel pitch as the highest resolution smart phones, but now in a 10.1-inch diagonal size. You’ll love it.
  2. The future of television
    For future TV, power savings will be critical. New technology from us and Samsung SEC combines a PenTile multiprimary LCD with field sequential color (FSC) and a 2D RGB LED backlight to achieve a very wide color gamut at the same time as the highest level of power savings. If you are display technologist, this demo will surprise you. You will see that it is now possible to remove color breakup, the main artifact associated with FSC.

WQXGA: What People are Saying

“The debate about when a “retina display” for tablets will exist is over: Samsung’s new 10.1-inch, 2560×1600 display is it. With a crazy pixel density of 300dpi, it rivals what Apple considers a retina display for a phone. But it’s for tablets… Our eyeballs can’t wait.”
- Gizmodo

“So what does all this mean to consumers? Basically — we’re going to be getting some seriously high quality displays in some of the upcoming tablets. Luckily for us, those displays will be lighter and 40 percent more power-efficient. Which, is a great thing — that stuff leads to lighter, visually better and longer lasting tablets.”
- Android Central

“From Samsung we’ll be seeing its 10.1-inch 300ppi prototype LCD panel, which rakes up an astonishing resolution of 2,560 x 1,600 under the battery-friendly PenTile RGBW matrix (not to be confused with AMOLED and Super AMOLED’s RGBG arrangement).”
- Engadget

“And if you weren’t already thinking it—yes, this is perfect for tablets.”
- Wired/Ars Technica

“[Samsung] just announced a 10.1-inch LCD display with 300 dpi (a measure of how many dots they’ve crammed into an inch—300′s high for a tablet) and WQXGA resolution, a staggering (and tablet-record-setting) 2560 by 1600 lines.”
- TIME’s TechLand

“Samsung’s new display does prove that high-res, tablet-sized displays are indeed possible without giving up power efficiency…”

“Samsung subsidiary Nouvoyance is set to reveal an impressive 10.1-inch LCD next week that could be used in future tablet computers.”

“The new PenTile WQXGA display has double the resolution found in the forthcoming Samsung Galaxy Tab 10.1 and has more than five times as many total pixels as the iPad’s 1024-by-768 display.”
- PC World

“Samsung has fit a version of its upcoming Galaxy Tab 10.1 tablet with a high-resolution screen that will rival high-end screens such as Apple’s retina displays.”
- LA Times

“Thought the iPad 2′s 1024 x 768-pixel screen was the last word in high-resolution tablet displays? How wrong you were.”
- Laptop Mag

“Samsung [is] getting ready to show the world their stunning new 10.1 inch LCD screen which has a staggering resolution of 2560×1600 pixels, normally reserved for 30 inch panels.”
- KitGuru

“While current display technology works just fine in tablets, having a higher resolution display will certainly improve the tablet experience, especially as displays approach the sharpness of print media.”
- MobileBeat

Welcome to WQXGA Sharpness

To date, all tablet displays have used formats like 1024 x 800 (the wide version of Super VGA). These products are designed to be thin and lightweight, so it has been a reasonable compromise to limit resolution to these formats to conserve power.

That’s not necessary for us.

With PenTile technology, we can achieve high resolution with one-third fewer subpixels, making it possible to make each subpixel larger and achieve higher aperture ratio – which lets more light pass through the open areas.

This has enabled resolutions of one-third MORE than legacy LCD technology, using the same amount of power. So now it’s possible to go beyond HD formats while retaining thinner and lighter tablet designs.  And, at the same time this enhances the quality of white and while still saving considerable power for longer times between recharges.

Say hello to 2560 x 1600, because that’s what you’re going to be seeing with WQXGA technology.


WQXGA Display Prototype