Digital paper, also known as interactive paper, is patterned paper used in conjunction with a

digital pen A digital pen is an input device which captures the handwriting or brush strokes of a user and converts handwritten analog information into digital data, enabling the data to be utilized in various applications. This type of pen is used in conjunc ...

to create handwritten digital documents. The printed dot pattern identifies the position coordinates on the paper. The digital pen uses this pattern to store handwriting and upload it to a computer.

The paper

The dot pattern is a two-dimensional

barcode A barcode or bar code is a method of representing data in a visual, Machine-readable data, machine-readable form. Initially, barcodes represented data by varying the widths, spacings and sizes of parallel lines. These barcodes, now commonly ref ...

; the most common is the proprietary Anoto dot pattern. In the Anoto dot pattern, the paper is divided into a grid with a spacing of about 0.3 mm, a dot is printed near each intersection offset slightly in one of four directions, a camera in the pen typically records a 6 x 6 groups of dots. The full pattern is claimed to consist of 669,845,157,115,773,458,169 dots, and to encompass an area exceeding 4.6 million km² (this corresponds to 73 trillion unique sheets of letter-size paper). The complete pattern

space Space is a three-dimensional continuum containing positions and directions. In classical physics, physical space is often conceived in three linear dimensions. Modern physicists usually consider it, with time, to be part of a boundless ...

is divided into various domains. These domains can be used to define paper types, or to indicate the paper's purpose (for example, memo formatting, personal planners, notebook paper, Post-it notes, et cetera). The Anoto dot pattern can be printed onto almost any paper, using a standard printing process of at least 600 dpi resolution (some claim a required resolution of 1,000 dpi), and

carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

-based black ink. The paper can be any shape or size greater than 2 mm to a side. The ink absorbs

infrared light Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those o ...

transmitted from the

; the pen contains a receiver that interprets the pattern of light reflected from the paper. Other colors of ink, including non-carbon-based black, can be used to print information that will be visible to the user, and invisible to the pen. Standard black and white laser printers or color laser printers with a resolution of 600 dpi can be used to print the Anoto dot pattern. With a typical CMYK color laser printer, it's possible use full-color text and graphics that cover the entire page by avoiding using black (i.e.,

under color removal In printing, under color removal (UCR) is a process of eliminating overlapping yellow, magenta, and cyan that would have added to a dark neutral (black) and leaving the black ink only, called a ''full black'', during the color separation process ...

is turned off) and instead use only Cyan, Magenta, Yellow, or any combination -- which are ignored by the pen -- and using the black (K component) only for the Anoto pattern. Standard black and white laser printers or color laser printers with a resolution of 600 dpi can be used to print the DataGlyph ''address carpet'' pattern. Redundant glyph marks support recovering the correct 2D location and angular orientation, even in the presence of overprinted text and line art.

References

{{Paper Computing input devices Paper Display technology

The paper

Further reading

References