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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  • Zan Lynx - Thursday, December 31, 2015 - link

    Or knows that you're supposed to set the screen brightness lower than the room. I've never had a problem reading on a phone or a tablet.
  • Tams80 - Sunday, December 20, 2015 - link

    It's great to see this device exist. If I was still in university, I'd really be lusting after it.

    It's fantastic to see they are using Wacom EMR. Yes, there are edge accuracy issues with it, but I still think it is the best AD implementation (Wacom Feel is stunted a bit by wacom, but an ereader like this doesn't really need tilt sensitivity).

    What I think it could do with though, is more hardware buttons. Some for page turning, and some as programmable hot keys.
    I also take it the document notes are kept on each page? It would be good if there was an aggregation feature for notes; that gathers a copy of them all together in a separate file that has no breaks in. A snapshot of context relevant text would also be good.

    Ultimately some colour would be ideal, but that's still some way off I take it.
  • Solandri - Sunday, December 20, 2015 - link

    " 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."

    This is a large part of the reason why these devices are overpriced and not successful. By insisting on displaying the entire A4 or Letter-sized page, you're wasting expensive screen real estate displaying blank margins. The device already has a bezel which acts as margins. You don't need to waste screen space showing that empty space. If the page has 2cm or 3/4" margins on all sides, then A4 becomes 12.1" diagonal with a 1.51 aspect ratio, US Letter becomes 11.8" with a 1.36 aspect ratio.

    Don't try to display the entire page, blank margins and all. Make the device 12" diagonal with a 1.5 aspect ratio and a white/grey bezel. Include a PDF reader which automatically zooms the page to eliminate margins, intelligently clipping lone outliers like the page number at the bottom of the comic book pic in your review. The device's screen area then decreases from 85 sq inches to 66.5 sq inches, or 78%, with a corresponding drop in weight and price, while giving up little to nothing in the size of displayed pages.
  • 10101010 - Monday, January 18, 2016 - link

    Perhaps in the "dead content" world of the Amazon Kindle and other DRM e-readers, a more optimized large format reader without margins could be made. But in the world of more interactive content, i.e. annotating/reviewing PDFs and such, the margins are very useful. Also, having a larger screen size gives the display software more flexibility, i.e. "keep bottom margin" or "keep side margins". For my needs, I wouldn't buy an e-reader like the one you are describing.

    So I think Sony is on the right track. The tech world still hasn't produced anything as good as paper yet -- 1200 dpi, full size, high quality pixels that don't kill your eyes, etc. It doesn't mean we should stop trying.
  • Tangey - Monday, December 21, 2015 - link

    the "better experience" of it's aspect ratio has nothing to do with the e-ink technology. Comparing it with a 4:3 tablet such as an ipad pro instead of the Dell, might have been a better decision.
  • flyguy29 - Monday, December 21, 2015 - link

    At $800, there should be nothing held back in terms of on board memory, processing power, and conveniences to make the product uniquely superior to tablets for books, documents and note taking.
  • 10101010 - Monday, January 18, 2016 - link

    Sony doesn't make the best decisions about how far to push the technology. They are learning, but for many years their policy was to self-cripple their hardware in one way or another.
  • TARRACARTER - Thursday, February 11, 2016 - link

    Helpful piece ! For what it's worth , if people is requiring to merge two PDF files , I merged a service here Altomerge
  • xrror - Thursday, February 11, 2016 - link

    I'd actually be tempted to invest in one of these... except as you say:

    "We hope Sony continues to provide firmware updates"

    Sony is really bad at letting products rot after the first year. If they don't manage to fix something within that year, they never fix it. And sadly these probably won't be common enough for a hacking community to form, so no modded firmwares to save either.

    Which sucks, because this DOES look really nice. Sony's worst enemy always seems to be Sony. *sigh*

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