Paper that talks back

Today there are large boards and shop displays that talk directly to customers, using digital information embedded in the paper. All the customer has to do is touch various parts of the display to get information to stream out of speakers printed into the paper.

Now research teams at the Mid Sweden University forestry industry research program Fiber Science and Communication Network (FSCN) are working on the fourth generation of paper products that can communicate with computers.

This integrates paper with the digital world.

How does this technology work?

"We combine paper with printed graphic codes and electronically conductive ink that is engineered to be sensitive to pressure. Then digital information is embedded in the paper, and when it is touched, the information comes out via speakers," said Mikael Gulliksson, project leader for media technology in the comprehensive research project.

What are some uses for digital paper?

Applications include advertising campaigns, marketing and events. The technology can also be used in product displays in shops.

For example, a large display board is marketing a new travel destination. The user touches a picture or text on the display board and then hears the audiovisual advertising message. Instead of a flat surface, this display board invites people to enter into and interact with the message.

The same technology has been used in a prototype for a 'music display board'. On a slightly bowed board, a number of music albums are printed directly on paper.

Just as with a regular sound system, you can sample music by touching the front of the album. The sound is then streamed out of the paper. The board can easily be replaced as soon as there are new recordings.

This form of display is inexpensive, combining images, sound and space in an environmentally friendly way. After use, the displays can be tossed into the recycle bin.

What is the aim of this project?

According to the researchers, the paper is not the digital solution but the paper might become the interface between existing digital devices.

How do the printed loudspeakers work?

The loudspeakers are based on a pattern on a thin conductive film. The researchers have tested both printing this pattern with conductive inks and creating the pattern by surface milling thin aluminium foils. The efficiency of the speakers depends on the ohmic losses in the conductors.

A strip of thin magnets is attached to the foil. In the display, the speaker membrane is placed over a thin cavity in the wellboard. The researchers have found a 5-15 mm cavity depth provides a wide frequency response.

In the video, the user can hear the sound clips stored in the display electronics (a digital mp3 electronic box), but not via the display as such. The sound files are identical but not recorded from the display speakers.

The sound quality is good enough to promote music and other audio CDs. The sound files are stored in a digital mp3 electronic box, also supporting the display functionality.

"The display is not the 'talking paper' people are dreaming of. It's an interactive billboard with simple speakers made of aluminium foil placed over a cavity in the material and some electronics behind the scene too!" Gulliksson said.

What are the advantages of using this technology?

Interactivity, as such, seems to create a richer user experience. If a display can generate a slightly more exciting user experience, at the point of sale in a shopping context, this might lead to new business opportunities.

What is next for digital paper?

"We will concentrate on down-scaling the display to a format suitable for packaging and see what might come out of that," Gulliksson said.

"We also plan to launch a conference on the digital paper and our search for new interactive print media technologies for magazines, displays, packaging as well as 2D coding," he said.