Optical characteristic evaluation method and optical characteristic evaluation system
An optical characteristic evaluation method evaluates unevenness of an optical characteristic in an optical film based on analysis of a polarized state of light transmitting through an optical film and an analyzer. The method includes the following, measuring a phase difference and an orientation angle in a plurality of positions; and quantifying and evaluating the unevenness of the optical characteristic based on a parameter of a vector of output light calculated by a formula 1 using a vector showing a polarized state of input light and a matrix showing a polarizing characteristic of the optical film and the analyzer. The formula 1 is as follows, formula 1: F2=M×F1, F1: Stokes vector or Jones vector of input light, F2: Stokes vector or Jones vector of output light, M: Mueller matrix or Jones matrix of the optical film as the evaluation target and the analyzer.
1. An optical characteristic evaluation method which evaluates unevenness of an optical characteristic in an optical film based on analysis of a polarized state of light transmitting through an optical film as an evaluation target and an analyzer, the method comprising:
measuring a phase difference and an orientation angle in the optical film in a plurality of positions; and
quantifying and evaluating the unevenness of the optical characteristic based on a parameter of a vector of output light calculated by the following formula 1 using a vector showing a polarized state of input light and a matrix showing a polarizing characteristic of at least the optical film and the analyzer,
wherein,
F 2= M×F 1, formula 1:
F1: Stokes vector of input light
F2: Stokes vector of output light
M: Mueller matrix of the optical film as the evaluation target and the analyzer,
wherein the unevenness of the optical characteristic is evaluated based on the analysis of the polarized state of the light transmitting the optical film through at least the following steps (1) to (8), wherein,
step (1): selecting a plurality of measured regions in a predetermined square area in the optical film as the evaluation target and measuring the phase difference and the orientation angle for each pixel in a predetermined size included in the measured region,
step (2): showing and setting the polarized state of the input light with a Stokes vector,
step (3): setting the Mueller matrix of the analyzer,
step (4): setting the Mueller matrix of the optical film for each pixel,
step (5): calculating the Stokes vector of the output light using the above formula for each pixel,
step (6): showing a parameter regarding an optical intensity in the Stokes vector of the output light for each pixel with gradation in a predetermined number of bits,
step (7): setting a threshold in the gradation representation and showing by binarization,
step (8): making an index of display irregularity using a result shown by binarization.
2. The optical characteristic evaluation method according to claim 1 , wherein the parameter of the vector of the output light is calculated by the following formula 2, wherein,
F 2= f 1× f 2× F 1, formula 2:
f1: Mueller matrix or Jones matrix of the optical film as the evaluation target
f2: Mueller matrix or Jones matrix of the analyzer.
3. The optical characteristic evaluation method according to claim 1 , wherein calculating is performed by setting conditions to satisfy the following formula 3 when the orientation angle of the optical film is θ 1 and the transmission axis direction of the analyzer is θ 2 ,
wherein,
|θ1−θ2|≤10°, formula 3:
θ 1 ≠θ 2 .
4. The optical characteristic evaluation method according to claim 1 , wherein calculating is performed by setting conditions to satisfy the following formula 4 when the orientation angle of the optical film is θ 1 and the transmission axis direction of the analyzer is θ 2 ,
wherein,
|θ1−θ2|≤2°, formula 4:
θ 1 ≠θ 2 .
5. An optical characteristic evaluation system which evaluates unevenness of an optical characteristic in an optical film based on analysis of a polarized state of light transmitting through an optical film as an evaluation target and an analyzer, the optical characteristic evaluation system comprising:
a hardware processor which is configured to,
measure a phase difference and an orientation angle in the optical film in a plurality of positions; and
quantify and evaluate the unevenness of the optical characteristic based on a parameter of a vector of output light calculated by the following formula 1 using a vector showing a polarized state of input light and a matrix showing a polarizing characteristic of at least the optical film and the analyzer,
wherein,
F 2= M×F 1, formula 1:
F1: Stokes vector of input light
F2: Stokes vector of output light
M: Mueller matrix of the optical film as the evaluation target and the analyzer,
wherein the unevenness of the optical characteristic is evaluated based on the analysis of the polarized state of the light transmitting the optical film through at least the following steps (1) to (8), wherein,
step (1): selecting a plurality of measured regions in a predetermined square area in the optical film as the evaluation target and measuring the phase difference and the orientation angle for each pixel in a predetermined size included in the measured region,
step (2): showing and setting the polarized state of the input light with a Stokes vector,
step (3): setting the Mueller matrix of the analyzer,
step (4): setting the Mueller matrix of the optical film for each pixel,
step (5): calculating the Stokes vector of the output light using the above formula for each pixel,
step (6): showing a parameter regarding an optical intensity in the Stokes vector of the output light for each pixel with gradation in a predetermined number of bits,
step (7): setting a threshold in the gradation representation and showing by binarization,
step (8): making an index of display irregularity using a result shown by binarization.