Scientifically, Do Retina Displays Make Sense?

By Anupum Pant

Our eye doesn’t work like a camera – with pixels and frame rates. It moves rapidly in small amounts and continuously updates the image to “paint” the detail. Also, since we have two eyes, both the signals are combined by the brain to increase the resolution further. Due to this, a much higher resolution image than possible with the eye’s abilities, can be generated in the brain. The very fact that we haven’t been able to come up with artificial devices that work the way a human eye does, confirms that we haven’t been completely able to understand this complex device yet.

But what we know about the average human eye is that its ability to distinguish between two points is measured to be around 20 arcsecs. That means, two points need to subtend an angle of at least 0.005 degrees to be distinguished by the human eye. Points lying any closer than that would mean that the eye would see it as a single point.

One thing needs to be noted that if an object subtends 0.005 degrees when it lies 1 foot away, it will subtend a lesser angle as it moves away. This is the reason you have to bring tiny text closer in order to read it. Bringing it closer increases the angle it subtends, only then the eye is able to resolve individual letters. Or in other words, anything is sharp enough if it is far enough.

Apple Science

Retina display, the Apple’s flagship display is said to be so sharp that the human eye is unable to distinguish between pixels at a typical viewing distance. As Steve Jobs said:

It turns out there’s a magic number right around 300 pixels per inch, that when you hold something around to 10 to 12 inches away from your eyes, is the limit of the human retina to differentiate the pixels. Given a large enough viewing distance, all displays eventually become retina.

Basically, Apple has done science at home and has come out with a nice number, 300 PPI. Practically, you don’t need anything higher than that. Technically, you do.

Isn’t “more” better?

No one is really sure. According to my calculations, an iPhone 5s’s display (3.5X2 in) would subtend 13.3 degree X 7.6 degrees from a 15 inch distance. With the kind of resolving power our eye sports, you’d need a screen that is able to display 4 megapixels on that small screen. Or in layman words, you need a screen that can pack around 710 PPI; practically, that sounds a bit too extreme (or maybe my calculations are wrong, please point it in the comments). I’d go with Steve Job’s calculation.

My shitty screen is a retina display

So, technically any device can said to be sporting the most touted screen in the industry today – a retina display – if it is kept at a sufficient distance. For instance, my laptop’s monitor with a resolution less than one quarters (~110 PPI) of what we see on today’s devices becomes a retina display when I use it from a distance of about 80 cm. 80 cm is normally also the distance I use my laptop from. Also, even doctors consider 50-70 cm as an optimum distance from screen to eye, to avoid eye strain.

On my shitty screen, the pixels are at a distance of 0.23 mm from center to center. And at 80 cm, my eye is practically unable to see the difference between a retina display and a shitty display. So, I say, do you really need higher and higher PPI devices? But that is just my opinion.

My Shitty phone is a retina display

As phones are generally used from a much closer distance, they require a higher PPI for the screen to look crisp. My phone, Lumia 520 has a 233 PPI screen. It becomes a retina display after a distance that is anything more than 15 inches. I’m required to hold my phone at 4 inches more than an iPhone to turn it into a display which is as good as an iPhone’s. Do I bring my phone any closer for anything? No. Do I need a higher PPI? No.


Recent phones from Samsung, Nokia and HTC pack in 316, 332 and 440 ppi, etc or more. Companies are spending billions to decrease the distance between their pixels. Sony, for instance, has recently come up with a 440 PPI display. And now, we have 4K TVs. Practically, I’d say, put an end to this manufacturer pissing contest and use this money for something more worthwhile. Technically, according to calculations, I say that we yet have to develop far more complicated technologies to cram in more pixels for pleasing the human eye.

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Understanding the Impending Helium Crisis

by Anupum Pant

There is too much Helium?

Helium is the second most abundant element in the observable universe, present at about 24% of the total elemental mass. Helium is also the second lightest element. So, 24% by mass is too huge a mass for a single light element. It equates to a measure that is probably millions of times more than what humanity could use up in millions of years. Close to about 12 times the mass of all the heavier elements combined, this element will almost never run out. But, that is only when we talk about the universe. Back in Earth, it is completely a different story.

Helium sources for us

On Earth, Helium is relatively rare. It amounts to only a 0.00052% volume of the earth’s atmosphere. Although 0.00052% is not too less, you also can’t consider it as an abundant element. Moreover, extracting Helium from air is almost 10,000 times more costly than fractional distillation (mentioned in the next paragraph). So, all that Helium in air is nearly useless to us till better methods of extraction are invented.
Thankfully, Helium is also present under the surface of the earth. The source of this kind of deposit is, radioactive decays which take place down there. It mixes with the natural gas and is lost to space, if released into the atmosphere. It is separated from natural gas using a process called fractional distillation – The best process to make Helium.

The largest known underground reserve estimated to contain about 10 billion cubic feet of Helium is a federal reserve (mostly under Texas and Kansas). For years US reserves had been the largest global suppliers of Helium (90%). Even today, these reserves contribute to more than 35% of the total global supply. The price of Helium coming from this source has remained almost unchanged for a long time. While during the same period (10 years) privately held Helium prices have tripled. The gap in prices is increasing every day, creating a big distortion in the market.

Helium Usage

Uses of Helium range from manufacturing smart phone screens (all LCD screens) to optical fibers (Internet cables) to health care (MRI scanners) to scientific research etc. [Uses of Helium]

The Problem

Since Helium has been made artificially cheap due to the Helium privatization act, it is popularly believed to be a cheap gas and is wasted a lot. Instead of using it up for important things, we consume it by filling up party balloons, distort voices and other entertaining activities. In fact, the warning issued by the Nobel Prize winner Robert Richardson that Helium could be depleted within a generation, seems to have had no effect on us. We still continue to waste a lot of Helium, release it into the air and keep losing it forever. Not many realize that it is a non-renewable resource.

We have almost reached a crisis already, but it was temporarily averted by the congress. In the future, after about 6-7 years, when the Federal Reserve stops supplying it (at below-market prices), it could be a big problem. I’m not very optimistic about market adjusting within such a small span either. In under a decade, we’ll probably see smart-phone prices, optical fiber prices and health care (MRI scans etc.) prices shoot up precipitously due to this artificial market distortion, if we do not start using Helium properly.