Who has the most spectacular tablet display: Amazon’s, Apple’s or Barnes & Noble’s? That’s what Dr. Raymond Soneira, president of DisplayMate Technologies Corporation of Amherst, N.H., set out to find out in his IPS tablet display technology shoot-out where he pitted Apple’s iPad 2 tablet against Amazon’s Kindle Fire device and Barnes & Noble’s Nook Tablet. The goal was to figure out which device packed the best IPS display. By the way -LG Displays, the world’s leading manufacturer of IPS LCDs- is the supplier of IPS panels for the three devices used in the shoot-out.
The iPad 2, the test note said, remains the gold standard in tablet displays while Motorola’s Xoom and Acer’s Iconia Tab serve as prime examples of low-quality LCD displays. The shoot-out praises iPad’s 132-ppi displays as being “virtually identical in performance to the impressive iPhone 4 Retina Display.” It is well calibrated, delivers bright images with excellent contrast, “reasonably accurate colors,” and very good viewing angle. A major drawback is that it has a reduced color gamut, although it is somewhat mitigated with the increased color saturation by steepening its intensity scale.
As for Amazon’s and Barnes & Noble’s tablets…
Cross-posted on 9to5Mac.com
The Fire’s display is on par with iPad 2’s and Nook Tablet’s in most respects, except for two aspects. The gray-scale rendered in the Fire’s Gallery app is limited to 16-bit and is “way off and overdriven so hard” that significant picture detail will be lost with bright images (it can be fixed with a firmware update). It sports an anti-reflective treatment that has about 70 percent higher reflectance levels compared to the iPad 2 and more than double the reflectance of the Nook Tablet that cannot be fixed in software. The latter is not a good thing for reading outdoors under bright sunlight or indoors with bright sources of light behind you.
As for Barnes & Noble’s Nook Tablet, it “has done a much better job in pulling everything together into a nice all around display.” It has the lowest reflectance of any tablet DisplayMate ever tested, showing 28 percent lower reflectance than the iPad 2 (yes, lower is better). Perhaps the most surprising finding is that the Nook Tablet’s gray-scale is “more accurate than most living room HDTVs.” Summing up: the Nook Tablet wins in display performance and picture quality while the iPad 2 comes “very close” with its top display performance overall. Amazon’s tablet has the worst display overall due to its high screen reflectance that cannot be fixed with a software update. More specs that are technical are found in the mega-table by DisplayMate (found at the article bottom).
IPS, or in-plan switching, is a premium display technology found on high-end devices, such as the iPhone 4, iMac and iPad 2. Developed by Hitachi in 1996, IPS uses crystals in the cells of the IPS panel that itself incorporates pairs of electrodes at the sides of each cell, running the electric field horizontally through the material. This results in wider viewing angles, better image contrast, faster response times and colors that pop compared to the cheaper LCDs used in many products.
DisplayMate was founded in 1984 and today specializes in video calibration, evaluation and diagnostic equipment for prosumers, technicians and OEMs. Dr. Raymond Soneira, pictured on the right, runs the company. According to his LinkedIn profile, Dr. Soneira has a PhD in Theoretical Physics from Princeton University. The renowned scientist is also a long-term member of the Einstein Institute for Advanced Study in Princeton. Interestingly enough, Dr. Soneira was caught in a catfight with Apple’s late co-founder and then CEO Steve Jobs following the iPhone 4’s debut in 2010. Shortly thereafter, Dr. Soneira emailed PCWorld.com in an effort to dispute Jobs’ claim that the iPhone 4’s 326ppi display meets or exceeds the maximum resolution that one’s retina under the perfect vision circumstances is capable of resolving (300 pixels per inch at a distance of ten to twelve inches).
This is what Dr. Soneira said:
The iPhone 4 has an outstanding display. And I’m glad that Apple resisted the emotional rush to OLEDs because they still need lots of improvement before they will be ready to compete with the highly refined IPS LCDs. The iPhone 4 display should be comparable to the outstanding IPS LCD in the Motorola Droid, which I tested and compared to the Nexus One OLED, which was trounced by the Droid.
Steve Jobs claimed that the iPhone 4 has a resolution higher than the retina – that’s not right:
1. The resolution of the retina is in angular measure – it’s 50 Cycles Per Degree. A cycle is a line pair, which is two pixels, so the angular resolution of the eye is 0.6 arc minutes per pixel.
2. So if you hold an iPhone at the typical 12 inches from your eyes, that works out to 477 pixels per inch. At 8 inches it’s 716 ppi. You have to hold it out 18 inches before it falls to 318 ppi.
So the iPhone has significantly lower resolution than the retina. It actually needs a resolution significantly higher than the retina in order to deliver an image that appears perfect to the retina.
It’s a great display, most likely the best mobile display in production (and I can’t wait to test it) but this is another example of spec exaggeration.
He later clarified:
The iPhone 4 is actually very far from a retina display. It’s a substantial discrepancy and not even close: At 12 inches the 1 dimensional linear difference is 326/477 = 68 percent. But the pixel (area) density for two dimensions, which is the actual relevant observable, is that value squared = 0.47, so the iPhone 4 is more than a factor of two from being a retina display at the typical 12 inch viewing distance. Stated another way: The iPhone display would need to have 1.3 megapixels instead of 0.6 megapixels to be a retina display.
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