Polarizing plate, method for manufacturing polarizing plate, image display device, method for manufacturing image display device, and method for improving transmittance of polarizing plate

A method for producing an image display device that comprises a polarizer disposed between a backlight source and an image display element in an image display device, the polarizer including a light-transmitting polyester substrate having in-plane birefringence and a polarizing element layered in said order,

• the method comprising the step of
• layering the light-transmitting substrate having in-plane birefringence and the polarizing element such that a fast axis of the light-transmitting substrate having in-plane birefringence along a direction in which the substrate shows a smaller refractive index and a transmission axis of the polarizing element form an angle of 90°±30°,
• the light-transmitting substrate having in-plane birefringence exhibiting a difference (nx−ny) between the refractive indexes of 0.05 or greater, where nx represents a refractive index in the direction of the slow axis in which the substrate shows a greater refractive index, and ny represents a refractive index in the direction of the fast axis that is orthogonal to the slow axis, and
• the thickness of the substrate being 10 to 300 μm.

A method for improving the transmittance of a polarizer disposed between a backlight source and an image display element in an image display device, the polarizer comprising at least a light-transmitting polyester substrate having in-plane birefringence and a polarizing element layered in said order,

• the method comprising the step of
• layering the light-transmitting substrate having in-plane birefringence and the polarizing element such that a fast axis of the light-transmitting substrate having in-plane birefringence along a direction in which the substrate shows a smaller refractive index and a transmission axis of the polarizing element form an angle of 90°±30°,
• the light-transmitting substrate having in-plane birefringence exhibiting a difference (nx−ny) between the refractive indexes of 0.05 or greater, where nx represents a refractive index in the direction of the slow axis in which the substrate shows a greater refractive index, and ny represents a refractive index in the direction of the fast axis that is orthogonal to the slow axis, and
• the thickness of the substrate being 10 to 300 μm.