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Adjustable Offset Vertical Reference Voltage of Thin Film Transistor to Focus all Light Vector on Eye Point for Liquid Crystal Display

IP.com Disclosure Number: IPCOM000116660D
Original Publication Date: 1995-Oct-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 6 page(s) / 148K

Publishing Venue

IBM

Related People

Hara, S: AUTHOR [+2]

Abstract

Disclosed is 'Adjustable Offset Vertical Vref. of Thin Film Transistor (TFT) to focus all Light vector on eye point for Liquid Crystal Display (LCD)' method. Fig. 4 shows 'Relationship between Vertical Vref. and Twist angle of LC (liquid crystal) among Upper end and Lower end of LCD screen'.

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Adjustable Offset Vertical Reference Voltage of Thin Film Transistor
to Focus all Light Vector on Eye Point for Liquid Crystal Display

      Disclosed is 'Adjustable Offset Vertical Vref.  of Thin Film
Transistor (TFT) to focus all Light vector on eye point for Liquid
Crystal Display (LCD)' method.  Fig. 4 shows 'Relationship between
Vertical Vref.  and Twist angle  of LC (liquid crystal) among Upper
end and Lower end of LCD screen'.

      So by changing 'Vertical Vref.  (=Vertical Reference Voltage)'
of TFT among Upper end and Lower end of LCD screen gradually, Twist
of Liquid Crystal depending on 'Vertical Vref.' can be varied a
little bit among Upper end and Lower end of LCD screen gradually.
And by focussing all Light vector (depending on Twist of Liquid
Crystal of LCD) onto eye point of Operator.  Finally operator can get
the improved uniformity of gradation brightness among Upper end and
Lower end of LCD screen from the eye point of operator in general
use.  And also, the compress of gradation and reverse of gradation
can not be seen in this range of 0 - 30 degree of viewing angle from
upper eye position.

      In addition, Vertical Vref. of TFT among Upper end and Lower
end of LCD is adjustable in order to corresponds to Aberration of LCD
array cell, or to the different panel size of LCD, or to the
different eye position (from 'upper' or 'lower', 'distance'), or to
the difference of using gradation level due to Application.

Viewing Angle range under general use of LCD: Fig. 1 shows 'Viewing
angle under general use of LCD in the case of Notebook-PC.  Fig. 2
shows 'Brightness VS.  Viewing angle characteristics of Conventional
LCD' Fig. 3 shows 'The model of Relationship of Light vector from
Upper end or Lower end into Eye point.  By these Figs. 1, 2 and 3,
the following specific viewing angle range can be led, from upper eye
position of operator in general use of Notebook-PC, it's visible
around 0 - 30 degree range as upper viewing angle at the same time.

      Then Fig. 2 also shows Conventional Characteristics of
Brightness related Viewing angle from upper eye position / or from
lower eye position as follows.  At the range of 0-30 degree of
Viewing angle from upper eye position, the Higher gradation level is
changing darker, on the other hand, Middle...