Mobile phone maker Nokia is seeking a US patent for tattoos that vibrate to let people know when they have calls on their mobile phones.

Technology laid out in a patent application available online Wednesday would enable tattoos to receive magnetic waves emitted by mobile phones.

Waves would trigger tattoos to generate "perceivable stimulus" to alert them to calls, messages, or batteries running low.

"The perceivable stimulus may comprise vibration, a vibration on the image on a user's skin, for example," according to the application filed with the US Patent Office late last year.

The application described an ink enhanced with magnetic compounds used to make visible or invisible images "attached to the skin."

Sensations caused by tattoos, permanent or temporary, could be customized depending on the content, suggesting vibrations could vary in intensity and timing depending on who was calling or whether it was a text message.

"The magnetic field, when detected by the apparatus, will cause a different effect based on its characteristics," the patent application read.

"For example, the magnetic field may cause vibration of one short pulse, multiple short pulses, few long pulses, mixture of short and long pulses, strong pulses, weak pulses, and so on."

People would be able to recharge tattoos using strong magnets, according to the application.