An optical structure comprising a textured layer made of ink

An optical structure configured to be placed in front of an image emitting device configured to emit an initial image adjusted by the optical structure to form an adjusted image to an observer, and the optical structure comprising:

• a textured layer placed on an observer's side of the optical structure;
• and the textured layer comprising at least a tactile pattern perceptible to the touch by a human body part, and the textured layer made of ink and comprising:
• a plurality of discrete ink dots, each having dimensions below 100 picometers (pm), the discrete ink dots forming all together the tactile pattern;
• and/or
• a plurality of discrete ink-free dots, each having dimensions below 100 pm, and the ink surrounding the discrete ink-free dots so as to form the tactile pattern.