Patent ID: 7272091

Claim:
A birefringence characteristic measuring method comprising the steps of: irradiating light onto a target medium for measurement via an objective lens having a numerical aperture equal to or higher than a predetermined numerical aperture, and measuring an amount of light of a polarized light component in a specific direction, which is included in reflected light reflected at a reflection surface of said target medium to thereby acquire a first amount of light A PH ; irradiating light onto said target medium via said objective lens having said numerical aperture equal to or higher than said predetermined numerical aperture, and measuring an amount of light of a polarized light component in said specific direction, which is included in reflected light reflected at said reflection surface of said target medium, and an amount of light of a polarized light component in a direction orthogonal to said specific direction to thereby acquire a second amount of light A NH ; and acquiring a perpendicular birefringence characteristic of said target medium based on a ratio A PH /A NH of said first amount of light to said second amount of light and an in-plane birefringence characteristic of said target medium.