Polarizer, method of producing polarizer, and optical laminate including the polarizer

1. A polarizer having a transmittance parameter represented by the equation (1) of 0.8 or more and a hue parameter represented by the equation (2) of 5 or less:

Transmittance parameter= T 420 /T 550   (1)

in the equation (1), T 420 represents a parallel transmittance at a wavelength of 420 nm and T 550 represents a parallel transmittance at a wavelength of 550 nm;

Hue parameter=√{square root over (( a 2 +b 2 ))}  (2)

in the equation (2), a represents a parallel hue value ‘a’ and b represents a parallel hue value ‘b’,

the polarizer has a thickness of 8 μm or less.

2. The polarizer according to claim 1 , wherein the polarizer contains iodine as a dichroic substance.

3. A method of producing the polarizer of claim 2 , the method comprising subjecting a laminate of a thermoplastic resin substrate and a polyvinyl alcohol-based resin layer to in-air stretching treatment, dyeing treatment, underwater stretching treatment, and drying shrinkage treatment in the stated order,

wherein a shrinkage ratio of the laminate in a widthwise direction by the drying shrinkage treatment is 1% or more, and

the polyvinyl alcohol-based resin layer comprises a halide and a polyvinyl alcohol-based resin.

4. An optical laminate, comprising:

the polarizer of claim 1 ;

a retardation layer configured to function as a λ/4 plate; and

a light-diffusing layer.

5. The optical laminate according to claim 4 , wherein the light-diffusing layer contains a pressure-sensitive adhesive and light-diffusing fine particles.

6. The optical laminate according to claim 5 , wherein the light-diffusing fine particles have an average particle diameter of from 2 μm to 5 μm.

7. A liquid crystal display apparatus, comprising the optical laminate of claim 6 .

8. The liquid crystal display apparatus according to claim 7 , wherein the liquid crystal display apparatus comprises a reflection-type liquid crystal display apparatus.

9. A liquid crystal display apparatus, comprising the optical laminate of claim 5 .

10. The liquid crystal display apparatus according to claim 9 , wherein the liquid crystal display apparatus comprises a reflection-type liquid crystal display apparatus.

11. A liquid crystal display apparatus, comprising the optical laminate of claim 4 .

12. The liquid crystal display apparatus according to claim 11 , wherein the liquid crystal display apparatus comprises a reflection-type liquid crystal display apparatus.

13. A method of producing a polarizer having a transmittance parameter represented by the equation (1) of 0.8 or more and a hue parameter represented by the equation (2) of 5 or less:

Transmittance parameter= T 420 /T 550   (1)

in the equation (1), T 420 represents a parallel transmittance at a wavelength of 420 nm and T 550 represents a parallel transmittance at a wavelength of 550 nm;

Hue parameter=√{square root over (( a 2 +b 2 ))}  (2)

in the equation (2), a represents a parallel hue value ‘a’ and b represents a parallel hue value ‘b’, the polarizer has a thickness of 8 μm or less,

the method comprising subjecting a laminate of a thermoplastic resin substrate and a polyvinyl alcohol-based resin layer to in-air stretching treatment, dyeing treatment, underwater stretching treatment, and drying shrinkage treatment in the stated order,

wherein a shrinkage ratio of the laminate in a widthwise direction by the drying shrinkage treatment is 1% or more, and

the polyvinyl alcohol-based resin layer comprises a halide and a polyvinyl alcohol-based resin.