Browse Prior Art Database

Light Reflector/Transmitter Design for Liquid Crystal Displays

IP.com Disclosure Number: IPCOM000114782D
Original Publication Date: 1995-Jan-01
Included in the Prior Art Database: 2005-Mar-29
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Hodgson, RT: AUTHOR [+3]

Abstract

A reflector/transmitter design for Liquid Crystal Displays (LCDs) with improved efficiency in the reflective mode is disclosed. The design includes a light pipe with a modified sheet of Totally Internally Reflecting (TIR) material, a reflecting sheet and fluorescent lamps which shine in the air space between the TIR material and the reflecting sheet. The roof prisms of the TIR material are oriented from said to side and face toward the reflecting sheet. This backlight assembly is placed behind the LCD.

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Light Reflector/Transmitter Design for Liquid Crystal Displays

      A reflector/transmitter design for Liquid Crystal Displays
(LCDs) with improved efficiency in the reflective mode is disclosed.
The design includes a light pipe with a modified sheet of Totally
Internally Reflecting (TIR) material, a reflecting sheet and
fluorescent lamps which shine in the air space between the TIR
material and the reflecting sheet.  The roof prisms of the TIR
material are oriented from said to side and face toward the
reflecting sheet.  This backlight assembly is placed behind the LCD.

      Unlike conventional TIR material which has a 90 degrees roof
prism angle, the modified TIR material has a roof prism angle on the
order of 100 degrees or more.  This modification results in more
overhead light being reflected preferentially in the viewing cone of
the LCD than would be the case with a conventional 90 degrees roof
prism TIR sheet with typical placement of the LCD screen in portable
computers during use.