How Anoto Paper Works

The Anoto input device is just a piece of ordinary paper on which a proprietary pattern of dots has been printed. To the eye this pattern is perceived as a slightly off-white color. The pattern of 6x6 dots uniquely defines the position on the full pattern, which encompasses an area exceeding 4.6 million km˛ (1.8 million miles˛). This corresponds to an area half the USA or the area of 73 trillion letter-size papers.

Construction The Anoto pattern consists of small dots with a spacing of 0.3 mm. These dots are slightly displaced from a grid structure to form the proprietary Anoto pattern. When writing with an Anoto pen on a paper printed with the pattern, digital snapshots of the pattern are taken every 1/100 second. Every snapshot contains enough information to make a calculation of the exact position of the pen. A special Function Pattern, that can be recognized directly by the pen, has been reserved for a limited number of commands, e.g. Store, Send, To Do, Address, etc.

Paper space The complete addressable area covered by the proprietary Anoto pattern, the paper space, is divided into numerous domains varying in size, some of which are pre-defined for certain applications like a digital notepad, while others are licensed to interested companies and authorities. The area within a domain can be used for a range of applications, each with its own functionality assigned. Certain areas of the paper domain with the Function Pattern can, for example, be pre-defined to be sent via a mobile phone to the Internet.

Printing The pattern can be printed on almost any paper or other suitable material allowing 1000 dpi resolution. The paper can be any desired size and shape depending on the intended use and design. A standard printing technique and ordinary black carbon-based ink are used. It is only the carbon-based black ink that will absorb the infrared light and make the pattern visible for the digital camera in the pen. This means that other colors, including noncarbon-based black, can be used to print whatever is required on top of the Anoto pattern without disturbing the function of the pen.

Anoto Paper Technical Specification

Paper quality: Standard
Printing technique: Standard offset
Pattern ink: Standard black
Dot spacing: Nominally 0.3 mm (0.01 inch.)
Total pattern size: 73 000 000 000 000 letter size pages
Minimum readable pattern area: 2x2 mm (0.08x0.08 inch)

Anoto Home Page