Patent ID: 8243356

Claim:
A security document, circuity comprising: an antenna arranged to receive EM-radiation from an external source and to convert it into electric energy; a rectifier arranged to receive electric energy from said antenna and convert said energy to a rectified current; and an electrochromic display arranged to receive rectified current from said rectifier, and to alter its electrochromic state in response to said rectified current in order to indicate the authenticity of a security document, wherein the electrochromic display comprises: a first pixel and a second pixel, each having an electrochromic layer and a counter layer electronically separated from each other, and a solidified electrolyte, which ionically connects said electrochromic layer and said counter layer of said first and second pixel, respectively, wherein the counter layer of said first pixel and said second pixel are electronically connected to a first gate electrode and a second gate electrode, respectively; the electrochromic layer of said first pixel electronically connects a first source electrode to a first drain electrode, the electrochromic layer of said second pixel electronically connects a second source electrode to a second drain electrode; each pixel comprises a switch portion of electrochemically active material arranged electronically between said source electrode and said drain electrode, which switch portion is in direct ionic contact with said solidified electrolyte; and a resistor being arranged between and electrically connected to a first contact portion and a second contact portion; said first drain electrode being connected to said second gate electrode; and both said first drain electrode and second gate electrode being connected to said first contact portion of said resistor, wherein said source and gate electrodes of said first pixel are arranged to receive and maintain a first potential difference; and said source electrode of said second pixel and said second contact portion of said resistor are arranged to receive and maintain a second potential difference; such that the voltage difference across the electrolyte of said second pixel is controllable by an increase in resistance between said source and drain electrodes of said first pixel.