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
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  • ganeshts - Friday, December 18, 2015 - link

    Thanks for the response with the link.

    The paper is similar to the SMR paper that I have in the photograph.

    The experience could definitely be better - I think Sony can achieve this right now just by shaving off the white margins.

    Ultimately, the device is held back by what E-Ink can provide to Sony. Given that the tech is stagnating for the last 4 - 5 years when it comes to HiDPI in EPDs, I am not sure what the solution will be.
  • melgross - Thursday, December 17, 2015 - link

    Zooming in is not a good solution. It's annoying, clumsy, and can be confusing at times. At best, it's an unsatisfactory "solution" to a problem other devices simply don't have.
  • JoeMonco - Friday, December 18, 2015 - link

    It was rather amusing that the article seemed to claim that low DPI didn't matter for text-heavy documents when one the major selling points of HiDPI displays is crisp, clear text.
  • zodiacfml - Friday, December 18, 2015 - link

    Pricey. At this price, Samsung might be able to produce an OLED screen of the same size.
  • JoeMonco - Friday, December 18, 2015 - link

    Low volume, niche products tend to be that way. Until the market for these devices grows, they'll stay expensive.
  • sheh - Saturday, December 19, 2015 - link

    Why do the pen tips need replacement? What kind of wear is there?
  • Tams80 - Sunday, December 20, 2015 - link

    Against the display. You don't want the pen tips to be harder than the display, or else they will scratch it.

    Having them to same hardness would make it difficult to make sure the display would have greater hardness, and if you pushed too hard with only a slightly lesser hardness pen tip, there would still be scratching.

    The hardness of the pen tip also contributes how the writing experience feels. We tend to use writing implements with medium-ish hardness.

    Therefore, the pen tips are softer than the display, and gradually wear away. It takes a long time; though that depends on the amount of usage (I've gotten well over a year using some Wacom tips).

    One difference between display and paper writing, is that using paper, the paper is the softer material, and that in order to write on it, you need to 'damage' it.
  • medi03 - Saturday, December 19, 2015 - link

    Guys, have you actually used e-reader device?

    "The e-reader market has lost some of its initial appeal due to the rapid rise in popularity of ...."... TABLETS? Seriously? Oh dear.

    Raising popularity of SUBSIDIZED Amazon Kindle killed the market for Sony.
    Sony PRS 500
    Sony PRS 505,300
    Sony PRS 600,900
    Sony PRS 350,650,950
    Sony PRS T1, T2, T3 (android based) => go compete with amazon which doesn't even need to make money on hardware

  • Zan Lynx - Thursday, December 24, 2015 - link

    I am not quite sure what you wanted to say about tablets vs e-readers.

    But I can say that I'm never going back to an e-reader. Because I get a full day use from my Surface tablet. It reads Kindle books, PDFs, HTML and Mobi formats. I charge it when I'm done using it.

    But of course a tablet can do a LOT more than a simple e-reader. It plays Netflix and Vudu movies, reads Facebook and the rest of the web, plays games, and even does word processing if I attach a keyboard.

    If I have to carry just one device it is a smartphone. Two devices, a smartphone and a tablet. Three devices is right out so no e-readers.
  • medi03 - Tuesday, December 29, 2015 - link

    People who read a lot use e-readers not because they need to be charged less often, but because it's much less strain on your eyes.

    So when anyone claims he just "switched over to tablets" either doesn't really read much, or has extraordinary eyes.

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