Browse Prior Art Database

LCD Backlight

IP.com Disclosure Number: IPCOM000123124D
Original Publication Date: 1998-May-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 36K

Publishing Venue

IBM

Related People

Ono, M: AUTHOR

Abstract

Disclosed is a design of LCD (liquid crystal display) backlight unit which uses energy from a light source efficiently. It can solve low lighting efficiency problem of super slim LCD modules for Notebook-PCs. To make a LCD module slim a light-guide of a backlight unit is made thinner. Main components of a LCD backlight are a light source unit, a light-guide, optical sheets, and a frame. Light emitted from light source unit goes into light-guide. Light energy transfer rate from a light source unit into a light-guide has a large effect on luminance of a LCD backlight unit. This rate depends on thickness of a light-guide's incident side. The smaller thickness of a light-guide incident side is, the lower luminance of backlight unit is.

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LCD Backlight

   Disclosed is a design of LCD (liquid crystal display)
backlight unit which uses energy from a light source efficiently.  It
can solve low lighting efficiency problem of super slim LCD modules
for Notebook-PCs.  To make a LCD module slim a light-guide of a
backlight unit is made thinner.  Main components of a LCD backlight
are a light source unit, a light-guide, optical sheets, and a frame.
Light emitted from light source unit goes into light-guide.  Light
energy transfer rate from a light source unit into a light-guide has
a large effect on luminance of a LCD backlight unit.  This rate
depends on thickness of a light-guide's incident side.  The smaller
thickness of a light-guide incident side is, the lower luminance of
backlight unit is.  This disclosed design backlight unit has a
condenser between a light source and a light-guide.  The condenser
increases light energy transfer rate from a light source into a
light-guide.  The condenser condenses the incident light vertically
to transfer all of light to a light-guide.

   Figure shows an example of this design implementation.  A
light source unit is composed of Cold Cathode Fluorescent Lamp (1)
and reflector (2).  Light emitted from a light source unit goes into
a condenser (3).  The condenser (3) condenses vertical height of
light.  The vertical height of condensed light is smaller than
thickness of incident side of a light-guide (4) at the incident
point.