Multilayer optical films, enabled structural color, structural colored pigment, and method of preparing the same

A structural colored pigment, formed from fragments of an optical film, wherein,

• the optical film comprises:
• a multilayer film, comprising a plurality of first films with a first refractive index and a plurality of second films with a second refractive index alternately arranged in a multilayer structure, wherein the multilayer film further comprises a middle film;
• wherein the middle film and films disposed at a same side of the middle film and having a same refractive index, have optical thicknesses which are all different or partially different;
• film characteristics of films in the multilayer film are:
• a1H a2L a3H a4L . . . a4L a3H a2L a1H;
• where H represents a typical first film with the first refractive index, and having a standard optical thickness of ¼ λH;
• L represents a typical second film with the second refractive index, and having a standard optical thickness of ¼ λL;
• the first refractive index is greater than the second refractive index;
• a1, a2, a3, a4 . . . are coefficients;
• and a2, a3, a4, . . . are in a range from about 0.1 to about 5 respectively, and a1 is 0 or in a range from about 0.1 to about 5;
• the multilayer film comprises a first layer, a second layer, a third layer, a fourth layer, a fifth layer, a sixth layer, and a seventh layer stacked on each other;
• a material of each of the second layer, the fourth layer, and the sixth layer is SiO2;
• a material of each of the first layer, the third layer, the fifth layer, and the seventh layer is TiO2;
• and the optical thickness of the first layer to the seventh layer is 223 nm, 162 nm, 171 nm, 194 nm, 171 nm, 162 nm, and 223 nm, respectively;
• and a maximum reflectance of the optical film is 90%;
• and
• the number of films of each of the fragments is the same as the number of the films in the optical film;
• and optical properties of the films of each of the fragments are the same as optical properties of those in the optical film.

An optical film, comprising:

• a multilayer film, comprising a plurality of first films with a first refractive index and a plurality of second films with a second refractive index alternately arranged in a multilayer structure, wherein the multilayer film further comprises a middle film as a middle film layer;
• wherein the middle film and films disposed at a same side of the middle film having a same refractive index, have optical thicknesses that are all different or partially different;
• film characteristics of films in the multilayer film are:
• a1H a2L a3H a4L . . . a4L a3H a2L a1H;
• where H represents a typical first film with the first refractive index, and having a standard optical thickness of ¼ λH;
• L represents a typical second film with the second refractive index, and having a standard optical thickness of ¼ λL;
• the first refractive index is greater than the second refractive index;
• a1, a2, a3, a4 . . . are coefficients;
• a2, a3, a4, . . . are in a range from about 0.1 to about 5 respectively, and a1 is 0 or in a range from about 0.1 to about 5;
• the multilayer film comprises a first layer, a second layer, a third layer, a fourth layer, a fifth layer, a sixth layer, and a seventh layer stacked on each other;
• a material of each of the second layer, the fourth layer, and the sixth layer is SiO2;
• a material of each of the first layer, the third layer, the fifth layer, and the seventh layer is TiO2;
• and the optical thickness of the first layer to the seventh layer is 364 nm, 407 nm, 414 nm, 390 nm, 414 nm, 407 nm, and 364 nm, respectively.