Browse Prior Art Database

Optical Elements of Liquid Crystal Display Backlights with Added Depolarizing Capability

IP.com Disclosure Number: IPCOM000119084D
Original Publication Date: 1997-Nov-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Tanase, H: AUTHOR

Abstract

Disclosed is a set of diffuse components of Liquid Crystal Display (LCD) backlights, which include diffuser sheet, diffuse dots printed on the light pipe, and diffuse reflector sheet, that enhance the performance of reflective polarizer sheets. Depolarizing capability is added to those elements by incorporating micro-spheres whose radii are in the range of 0.3 micrometers through 0.8 micrometers.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 83% of the total text.

Optical Elements of Liquid Crystal Display Backlights with Added
Depolarizing Capability

      Disclosed is a set of diffuse components of Liquid Crystal
Display (LCD) backlights, which include diffuser sheet, diffuse dots
printed on the light pipe, and diffuse reflector sheet, that enhance
the performance of reflective polarizer sheets.  Depolarizing
capability is added to those elements by incorporating micro-spheres
whose radii are in the range of 0.3 micrometers through 0.8
micrometers.

      With an aim at reducing the 50% loss incurred by a dichroic
polarizer in an LCD, reflective polarizer sheets have been developed.
It relies on repeated transmission of a first polarization component
and reflection  of a second and its subsequent depolarization by
diffuse elements in the backlight.  Therefore, the performance of a
reflective polarizer sheet incorporated in an LCD depends greatly on
the efficiency  of depolarization by those diffuse elements.

      Depolarizing capability of the diffuse elements of backlight is
strengthened by dispersing on or mixing into them micro-spheres whose
radii are in the range of 0.3 micrometers through 0.8 micrometers.
The effective radii of the micro-spheres thus incorporated are
maintained either by the use of a low viscosity fixing agent so that
the physical  contours of the micro-spheres are preserved (Fig. 1) or
by the use of a  fixing agent whose refractive index is at least 0.2
different from that  of the micro-s...