Patent ID: 11874560
Assignee: 3M INNOVATIVE PROPERTIES COMPANY
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A backlight for providing uniform illumination to a display panel, comprising:
a plurality of discrete light sources forming an array of rows and columns of discrete light sources, each discrete light source configured to emit an unpolarized blue light at a blue wavelength in a range from about 410 nm to about 470 nm;
a multilayer polymeric partial reflector disposed on the plurality of discrete light sources, for substantially normally incident light and for each of orthogonal first and second polarization states, the partial reflector comprising:
a reflection band comprising the blue wavelength;
a reflectance greater than about 80% at the blue wavelength;
a left band edge between about 370 nm to about 420 nm;
a right band edge between about 500 nm and 600 nm; and
an average transmission between about 20% to about 80% for visible wavelengths greater than the right band edge; and
a reflective polarizer disposed on the partial reflector, for substantially normally incident light having the blue wavelength, the reflective polarizer reflecting at least 60% of the light having the first polarization state and transmitting at least 60% of the light having the second polarization state.