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75‐3: Highly Collimated Backlight for Liquid Crystal Displays
Author(s) -
Berteloot Brecht,
Beeckman Jeroen,
Stuyven Gert,
Vermeirsch Koenraad,
Blomme Tom,
Neyts Kristiaan
Publication year - 2020
Publication title -
sid symposium digest of technical papers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.351
H-Index - 44
eISSN - 2168-0159
pISSN - 0097-966X
DOI - 10.1002/sdtp.14072
Subject(s) - backlight , collimated light , liquid crystal display , full width at half maximum , optics , contrast ratio , materials science , contrast (vision) , hexagonal crystal system , diode , optoelectronics , light emitting diode , liquid crystal , ray tracing (physics) , flat panel , beam expander , physics , chemistry , laser , crystallography , laser beams
In this work, we present the design of a collimated backlight design that can be used for a liquid crystal display. The design is based on a hexagonal array of white light emitting diodes (LEDs) in combination with two arrays of lenses. Ray tracing simulations show a full width ‐ half maximum (FWHM) collimation angle of 2.8º with a uniformity of 73%. A prototype of this design has been fabricated and its performance has been analyzed. Compared to a standard backlight, the collimated backlight provides a 4.2 times better contrast ratio for a twisted nematic (TN) liquid crystal (LC) panel. In combination with a diffusor in front of the LC panel, the contrast ratio under a wide viewing angle is improved by a factor of 10 and the color shift is reduced by 79%.