Optical layered body, polarizer, method for producing polarizer, image display device, method for producing image display device, and method for improving visibility of image display device

A polarizer that is configured to be disposed on a surface of an image display device, the polarizer comprising:

• a polarizing element;
• and
• an optical layered body disposed on the polarizing element,
• the optical layered body including:
• a light-transmitting substrate having in-plane birefringence;
• an optical functional layer disposed on one surface of the light-transmitting substrate;
• and
• a primer layer disposed between the light-transmitting substrate and the optical functional layer,
• the light-transmitting substrate having a slow axis with a greater refractive index,
• the polarizing element having an absorption axis,
• the optical layered body and the polarizing element being disposed such that the slow axis of the light-transmitting substrate and the absorption axis of the polarizing element are orthogonal to each other,
• the polarizer being configured to be disposed on a display screen of the image display device such that the slow axis of the light-transmitting substrate is in parallel with a vertical direction of the display screen, and
• the primer layer has a refractive index np that falls between a refractive index ny in a fast axis direction of the light-transmitting substrate and a refractive index nx in the slow axis direction of the light-transmitting substrate ny<np<nx.

A method for producing an image display device, the image display device including

• an optical layered body that has a light-transmitting substrate having in-plane birefringence, an optical functional layer disposed on one surface of the light-transmitting substrate, and a primer layer,
• the light-transmitting substrate having a slow axis that extends along a direction showing a greater refractive index,
• the method comprising:
• disposing the optical layered body such that the slow axis of the light-transmitting substrate is in parallel with a vertical direction of a display screen of the image display device;
• forming the primer layer disposed between the light-transmitting substrate and the optical functional layer,
• wherein the primer layer has a refractive index np that falls between a refractive index ny in a fast axis direction of the light-transmitting substrate and a refractive index nx in the slow axis direction of the light-transmitting substrate ny<np<nx.

A method for improving visibility of an image display device, the image display device including

• an optical layered body that has a light-transmitting substrate having in-plane birefringence, an optical functional layer disposed on one surface of the light-transmitting substrate, and a primer layer,
• the light-transmitting substrate having a slow axis that extends along a direction showing a greater refractive index,
• the method comprising:
• disposing the optical layered body such that the slow axis of the light-transmitting substrate is in parallel with a vertical direction of a display screen of the image display device;
• forming the primer layer disposed between the light-transmitting substrate and the optical functional layer,
• wherein the primer layer has a refractive index np that falls between a refractive index ny in a fast axis direction of the light-transmitting substrate and a refractive index nx in the slow axis direction of the light-transmitting substrate ny<np<nx.