Optically variable identification element FEEL-ID
A composite security feature based on colour changing and thermochromic effect. It was developed by Giesecke&Devrient company. FEEL-ID has a multilayer structure: 1) The top layer is made using STEP security feature with liquid crystal pigments; 2) The middle layer is made of thermochromic ink; 3) The bottom layer contains laser-engraved identification information (holder's portrait, etc.).
FEEL-ID characteristic features:
- its colour changes at different angles of observation and illumination (colour changing effect, STEP element);
- identification information hidden beneath the thermochromic ink layer is revealed when exposed heat (thermochromic effect).
FEEL-ID element structure
a
b
c
d
e
f
Hungary. Passport (2006):
а — data page. FEEL-ID element location; b — FEEL-ID element viewed at a right angle of observation and illumination; c — the same image viewed at an acute angle of illumination and observation; d — view through a polarizer: the dark area on the right indicates that the light reflected from the FEEL-ID element is circularly polarized; e — thermochromic effect: when exposed to heat, thermochromic ink becomes transparent revealing the document holder's portrait; f — laser engraved holder's portrait on the bottom layer. View in IR 840 nm