Since the advent of eBooks, digital book sales have increased over 43x. The primary reasons for this are ease of use, portability, the ability to store hundreds of books on one device, and the digital features that eBooks offer. Some of these features include automatic page detection and sharing on social media, both of which don’t exist for paper books. 

Despite the advantages, the vast majority of people claim to prefer paper books to the digital alternative; however, their feature-laden digital alternatives are threatening a paper future. 

Printed versus eBook purchases by population. Image used courtesy of Statista

Looking to combine the best of both worlds, researchers at the University of Surrey have come up with “The Magic Bookmark,” an electronic device that they hope can augment paper books to offer many of the same features like a digital one. 

This article will go over how the device works and how it compares to its predecessors. 

Current Techniques for Electronic Bookmarks 

At this point, there have been two primary techniques used to create electronic bookmarks for augmenting paper books. 

The first technique is LightTags, which consists of printed organic photovoltaics (OPVs) that get physically embedded in the paper. Each page in the book consists of a unique combination of OPVs connected to a readout circuit, creating a 4-bit code that uniquely identifies the page number. 

Structure of a LightTag. Image used courtesy of Bairaktaris et al

While the technique works for open page detection, it offers many challenges, like those with system handling and manufacturability. 

First, the lamination technique results in the paper becoming 3x as thick as it would be, making it brittle and removing the natural feel of paper. On top of this, embedding sensors in between the pages is an irreversible process and significantly drives up the cost of each book.

The second technique is known as the Digital Bookmark. The Digital Bookmark works by integrating printed conductors on a book's pages and commercial electronics to synchronize the paper and eBook versions of the same content. 

This technique requires each page to have a unique conductive so that the electronics attached to the top of the book can translate the printed code into a page number. This technique can be cumbersome as the bulky device requires the reader to unclip, align, and reclip the electronics. Also, each page cannot be manufactured sustainably due to the embedded conductive material. 

Hoping to progress beyond those two techniques is the "Magic Bookmark."

The Magic Bookmark 

With the Magic Bookmark, researchers at the University of Surrey sought to create an electronic bookmark that avoided problems of its predecessors, namely sustainability and handling. The researchers describe that the system works by first having each page printed with a unique code (barcode and/or QR code) near the book's spine. 

The Bookmark itself is then a device consisting of a strip of flexible electronics, including embedded sensors. 

The sensors consist of an infrared LED and an infrared-sensitive phototransistor pair. When the control electronics make a page number query, all of the LEDs illuminate the page, and the phototransistors capture the reflected light at each location. Their output is also wired to a microcontroller unit (MCU) pin, allowing the MCU to determine the page number. 

The Magic Bookmark. Image used courtesy of the University of Surrey

The technique has two major advantages over previous attempts. First off, it is completely sustainable. Where previous techniques required electronics embedded into the paper, the Magic Bookmark's system simply prints codes on paper like any other text. 

Beyond this, the Magic Bookmark is not cumbersome or difficult to use. Like a normal bookmark, the user has to insert it in the book with minimal alignment, and the sensors can easily access the necessary information.

Moving forward, the University of Surrey researchers hope to explore using fully printed photosensors, so that their Magic Bookmark looks and feels like a conventional bookmark. It will definitely be interesting to see how this technology develops and if it can make its way to market.