Patent ID: 11921367
Assignee: REALD SPARK, LLC
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 17:
18. The display device according to claim 1, wherein the operational image is visible, or is not visible, when a security factor Sn defined at an angle in question is, for all the plural regions, less than 1.0, or at least 1.0, respectively, where the security factor Sn is given by the equation:

Sn=log10[1+ρn·α/(π·Pn)], wherein:
ρn is a reflectivity of the display device at the angle in question;
Pn is a ratio of a luminance of the display device at the angle in question to a maximum luminance of the display device;
π is a solid angle in units of steradians; and
α is a factor having a value of 4.0 steradians.