Reflective optical film and method of manufacturing the same, and image display device

An image display device, comprising:

• a reflective light-polarizing unit including a multilayer reflective sheet composed of a plurality of polymer films stacked on top of one another, wherein each polymer film has a thickness, every two adjacent polymer films are two different materials, the thicknesses of the polymer films are gradually decreased from two outmost sides of the multilayer reflective sheet to a middle of the multilayer reflective sheet, at least one of the polymer films is a birefringence material layer that conforms to the condition of NX≠NY≠NZ, wherein NX is the index of refraction of light at X direction of the multilayer reflective sheet, NY is the index of refraction of light at Y direction of the multilayer reflective sheet, and NZ is the index of refraction of light at Z direction of the multilayer reflective sheet;
• and
• an image display unit including at least one image display screen, wherein the reflective light-polarizing unit is disposed on one of the top side and the bottom side of the at least one image display screen or between the at least one image display screen and a backlight module.

A method of manufacturing a reflective optical film, comprising:

• forming a multilayer reflective sheet composed of a plurality of polymer films stacked on top of one another by a co-extrusion process, wherein each polymer film has a thickness, every two adjacent polymer films are two different materials, the thicknesses of the polymer films are gradually decreased from two outmost sides of the multilayer reflective sheet to a middle of the multilayer reflective sheet, at least one of the polymer films is a birefringence material layer that conforms to the condition of NX #NY#NZ, wherein NX is the index of refraction of light at X direction of the multilayer reflective sheet, NY is the index of refraction of light at Y direction of the multilayer reflective sheet, and NZ is the index of refraction of light at Z direction of the multilayer reflective sheet;
• and
• extending the multilayer reflective sheet.