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Bias-Voltage Applying to Liquid Crystal Display Using Retardation Film to Spread Viewing Cone

IP.com Disclosure Number: IPCOM000117729D
Original Publication Date: 1996-May-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Nakamura, H: AUTHOR [+3]

Abstract

Fig. 1 V-T Curve of a LCD Compensated with Film at RED(60nm), GREEN(550nm), and BLUE(450nm)

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Bias-Voltage Applying to Liquid Crystal Display Using Retardation
Film to Spread Viewing Cone

   Fig. 1 V-T Curve of a LCD Compensated with Film at RED(60nm),
GREEN(550nm), and BLUE(450nm)

      This disclosure shows the advantage of bias-voltage applying to
the TN-Liquid Crystal Display (LCD) panel which has a retardation (or
compensation) film to spread a viewing-cone when it uses a
birefringence light.

      There are many ways to spread the viewing-cone of TN-LCD panel
to improve front-of-screen quality.  One of the candidates is to
apply a compensation film with a birefringence light.  When the
compensation film is applied to the TN-LCD panel with birefringence
light, the applied voltage-light transmittance (V-T) characteristics
have a strong dependency on the wavelength of outgoing light,
especially for the short wavelength.  Appended Fig. 1 shows the V-T
curve of the compensated panel, using birefringence light, for red
(typically 600nm in wavelength), green (550nm), and blue (450nm).
For red and green, transmitance is simply reduced against the
applying voltage.  However, there is a peak of transmittance on the
middle voltage for blue.  An LCD panel displays many colors to change
transmittance for RGB each by control of applied voltage.  So that,
the applied voltage is controlled precisely at a range of 0 to some
(5V, typically).

      As shown in Fig. 1, it has a larger transmittance of blue at
about 1.8 volt rather than that at 0 volt.  Then...