The e-reader market has lost some of its initial appeal due to the rapid rise in popularity of tablets and other similar mobile devices. However, 'tablets' with E-Ink screens continue to offer the best reading experience in terms of reducing eye strain as well as providing long battery life. E-Ink screens have not scaled well in size, with the 6" screen size being the most popular and economical choice. Products with bigger screen sizes such as the Kindle DX (9.7") have not enjoyed market success.

E-Ink - A Brief Background

We will not go into the technical details of E-Ink here, but it suffices for readers to know that E-Ink avoids the use of backlighting. Instead, it relies on reflection from ambient light for visibility. In the latter aspect, it is very close to real printed paper. The major downside is that the refresh rate of E-Ink screens is very slow and only the monochrome technology is mature enough for mass consumption in the e-reader market.

E-Ink screens have been trying to evolve in two different ways. On one hand, we have attempts being made to get some sort of color display with E-Ink characteristics. On the other hand, E-Ink is trying to bring out flexible displays as well as produce larger sized screens. While screens of up to 32" in size are available for digital signage purposes, the maximum size currently supported for direct-to-consumer sales is 13.3".

The Need for a 13.3" E-Reader

Most of our workload nowadays involves sitting in front of a computer monitor and/or staring at tablet/smartphone screens. It is common for people to experience eye fatigue due to these activities. Having used multiple tablets and phablets for content consumption, I realized that none of them fit the bill when it came to reading technical documents or annotating them for future reference. In addition, all these technical documents are typeset in either A4-sized (8.27" x 11.69") or US Letter-sized (8.5" x 11") pages. This ruled out usage of any of the large number of e-readers based on the 6" E-Ink platform. A4 and US Letter correspond to diagonals of 14.3" and 13.9" respectively. 13.3" with an aspect ratio of 4:3 is ideal for displaying documents typeset in either A4 or US Letter-sized pages.

The Sony DPT-S1 - A 13.3" E-Ink Device

Sony's Digital Paper System (DPT-S1) was launched in April 2014. It takes things to a whole new level by making use of a 13.3" E-Ink Mobius screen. It was launched with a price tag of $1100, and was quite unpalatable for the ordinary consumer. It comes with a stylus / pen for taking notes as well as PDF annotation, and business users are its main target.

Initially, my impression was that lower priced variants with the same screen would soon appear in the market and target the average e-reader. Unfortunately, we are at the end of 2015, and the Sony DPT-S1 remains the only E-Ink Mobius-based product that consumers can purchase in the market. A little bit of silver lining lies in the fact that Sony has steadily been bringing the price down (from $1100 at launch to $800 right now).

The Sony DPT-S1 comes in a nondescript box. The package consists of a quick start guide, the e-reader in a leather sleeve, the pen / stylus, three replacement tips for it along with a tool to aid in pulling out the old tips, and a 7.5W (5V @ 1.5A) USB charger with a USB to micro-USB cable. The gallery below provides high-resolution pictures of the various components.

As can be seen from the gallery above, the main reader is like a sheet of white paper surrounded by a thick bezel. The bottom bezel is slightly thicker to accommodate the navigation and context menu buttons at the center with the power button at the right corner. The power button is on a slanted panel and is not flush with the rest of the frame - this prevents accidental pressing of the power button during use.

The important aspects of any e-reader are the dimensions and the weight. While the unit as a whole comes in at 9.125" x 12.125", the viewable area / screen is 8" x 10.625" (corresponding to a diagonal size of 13.3"). Note that this needs to be compared to an A4 sheet (8.27" x 11.69") and a US Letter sheet (8.5" x 11"). The viewable area is slightly smaller than both of them, but definitely much better than the 9.7" E-Ink screensfor documents typeset with those page dimensions.

The weight of the reader alone is 355g, while the stylus/pen adds an extra 9g. Placed in the supplied sleeve, the complete package weighs in at 496g. All said, the unit is quite ergonomic to use - both in hand, as well as on a table. The screen has a pixel resolution of 1600 x 1200 and can display 16 levels of grayscale. It is likely that most use-cases for the DPT-S1 involve text-heavy documents. The DPI and color limitations are not much of a concern.

In the rest of the review, we will take a look at the hardware platform in detail and follow it up with a look at the software aspects before providing some concluding remarks.

Hardware Platform
Comments Locked


View All Comments

  • melgross - Thursday, December 17, 2015 - link

    I've used Kindles for a while, and never liked them. The screens bother me. The brightness changes outdoors depending on whether a cloud passes by. Generally, they're ok, but not great. The disadvantages far outweigh the advantages, which are just two, length of battery life, and..., well, that's just one.
  • name99 - Thursday, December 17, 2015 - link

    As someone who alternates a lot between substantial amounts of paper and iPad reading (though not eInk) I'd say that, at least for me and everyone in my family, melgross is correct. I have no experience of eye strain or any other issues when reading my iPad as opposed to paper. Maybe this is because I set the iPad brightness at something that makes sense rather than reading at nuclear flare level in a dark room?
  • phexac - Friday, December 18, 2015 - link

    And this is especially the case since we've transitioned to LCD tech that doesn't generate image by redrawing it multiple times per second. To me THAT was what caused strain. LCDs don't actually refresh the image unless it changes, which makes reading static things such as text on them a lot easier.

    And iPads have some of the best LCDs out there (I am comparing shitty TN panel laptops etc. here, that could conceivably be hard on the eyes cuz they are so shitty).
  • nikon133 - Thursday, December 17, 2015 - link

    Just wondering... it would make more sense comparing this with Surface Pro 3 or 4... or iPad Pro... than 16:9 Dell, for reading comics.
  • ganeshts - Thursday, December 17, 2015 - link

    I was looking for a 13.3" screen - closest to what the DPT-S1 has.

    I would definitely provide additional comparative photographs if I had access to a SP3/4 or iPad Pro :)
  • digiguy - Thursday, December 17, 2015 - link

    I think the ipad pro or the surface book are a much better size to be compared with. Surface pro 3/4 is smaller. I bought an ipad pro because I wanted true A4 size, which my Surface pro 3 could not do (ipad pro screen is basically as big as surface pro 3/4 including bezels). Surface book displays PDFs of the same size as ipad pro because of the different aspect ratio (try putting them next to each other and display a PDF full screen)
  • imaheadcase - Thursday, December 17, 2015 - link

    You know what i am surprised does not exist, a paper notebook, but with Ereader paper inside. I can't tell you how many times I would love to write in a notebook, and it sends it to my computer instantly(or at least when WiFi is near) as text notes to remember later. It would be great for businesses as well, jot down notes, it sends it to certain people or groups of people.

    But that is the hardest part of tech like this, figuring out what is PRACTICAL in a work environment. I think the biggest challenge in the next coming years is not tech advances, its UI design and feasible hardware design for the end user.

    I work at Walmart, i can tell you they spend MILLIONS every year on tech that is thrown on the next year because it simply does not do what they are sold on. For example, they spent $800 on motorolla handhelds for inventory...for 4000+ stores, around 25 each store. Not a single person in stores like them. They have terrible UI, slow, can't connect to WiFi in stores fast, etc.
  • melgross - Thursday, December 17, 2015 - link

    I had a chance to try this for about an hour, earlier this year, and I wasn't overly impressed. While it's fine for general purposes, the screen is coarse when trying to read smaller type. It's somewhat unpleasant because that coarseness eliminates differences between typefaces in anything under 8 points, a size that is common, and even somewhat in 10 point. That makes readability less than comfortable at smaller type sizes, even though it's legible.

    Another problem is that anywhere the light isn't bright, the screen suffers, rapidly becoming difficult to read at dimmer levels. I found myself snuggling closer to the light, which was an annoying experience. For this price, something should have been done to add side lighting.

    It's slow, and anyone used to a decent tablet will be frustrated by that. It becomes old, fast.

    Graphics are also coarse when grey shades are present.

    I didn't get a chance to try the stylus, so I can't comment on that. But for the money, there are much better choices. As far as eye strain goes, it's been shown that we can't tell the difference between reflected light and transmitted light. A lot of people who get eye strain get it because they have the screen adjusted incorrectly, not because of the screen type.
  • ganeshts - Thursday, December 17, 2015 - link

    Can you link me to a PDF that has this problem? I would genuinely like to try out.

    The 'smallest text size' PDF I tried to read was this: , and when I had trouble, I could just zoom in and read it properly (as shown in the pic to the right).

    I would venture to suggest that if a PDF is having readability problems with this device, things are going to be a lot worse with anything else in this form factor.
  • name99 - Thursday, December 17, 2015 - link

    My quick calculation is that the DPI is 150, and with only limited grey scale to handle anti-aliasing, rather than the subpixel many-level anti-aliasing available on a color screen. So you're looking at something like iPad resolution not iPad retina resolution.
    The difference for technical documents between iPad and iPad retina resolution was/is immediately obvious. Take any random modern technical PDF, something like this

    I don't have access to an old iPad, but I can immediately see the difference between how this looks on my (non-retina) iMac and on an retina iPad, and I suspect that on current eInk it looks like the non-retina version. (Certainly that's what you photo seems to show, though admittedly a photo is a non-ideal way to resolve the issue.)

Log in

Don't have an account? Sign up now