Backlight module

Details Backlight module Backlight module

2002-09-13

2004-06-29

O'Shea, Sandra (Department: 2875)

Illumination

Revolving

C027S021100

Reexamination Certificate

active

06755548

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a backlight module, and in particular to a backlight module reducing the thickness and weight of an LCD device.
2. Description of the Related Art
Referring to
FIG. 1
, a conventional backlight module
1
for an LCD device includes a glass panel
2
, a light guide plate
4
and two symmetric illumination assemblies
6
. A diffusing film (not shown) and a brightness enhancement film (not shown) are disposed on the glass panel
2
. A reflecting film (not shown) is disposed under the light guide plate
4
. The illumination assembly
6
has two lamps
6
a
,
6
b
arranged in a line and a reflector
6
c
. The lamps
6
a
,
6
b
transmit light to the light guide plate
4
directly. Also, the lamps
6
a
,
6
b
transmit light to the light guide plate
4
by reflection of the reflector
6
c
and the light is absorbed and diffused by a plurality of optical dots (not shown) formed on the bottom of the light guide plate
4
.
Generally speaking, the diameter of the lamps
6
a
,
6
b
is 2.4 mm. The lamps
6
a
,
6
b
are spaced from each other by a predetermined distance such that light or light energy is not absorbed and illumination of the light guide plate
4
is not reduced. In addition, a predetermined distance exists between the lamp
6
a
and the reflector
6
c
and between the lamp
6
b
and the reflector
6
c
to ensure reflection. Thus, the thickness t
1
of the light guide plate
4
of the conventional backlight module
1
is 8 mm.
Referring to
FIG. 2
, another conventional backlight module
10
provides a light guide plate having reduced thickness. Elements corresponding to those shown in
FIG. 1
are given the same reference numerals, and explanation thereof will be omitted for simplification of the description. The backlight module
10
includes a glass panel
2
, a light guide plate
4
and two symmetric illumination assemblies
6
′. The illumination assembly
6
′ has two lamps
6
a
,
6
b
arranged obliquely and a reflector
6
′
c
. Similarly, the diameter of the lamps
6
a
,
6
b
is 2.4 mm and the illumination of the light guide plate
4
in the backlight module
10
is the same as that in the backlight module
1
. The thickness of the reflector
6
′
c
can thus be reduced. Namely, the thickness t
2
of the light guide plate
4
of the backlight module
10
is reduced to 6 mm.
Nevertheless, the aforementioned backlight modules
1
,
10
are still overly thick (8 mm, 6 mm) though they maintain enough illumination.
Consequently, the invention provides a backlight module for an LCD device. The backlight module provides an improved structure of the illumination assembly and improved arrangement of the illumination lamps thereof. The illumination of the LCD device is not adversely affected and the weight and thickness of the backlight module are reduced, as are the weight and thickness of the LCD device itself.
SUMMARY OF THE INVENTION
An object of the invention is to provide a backlight module. The backlight module comprises a glass panel, a light guide plate and an illumination assembly. The light guide plate is disposed under the glass panel and has a connection side. The illumination assembly is disposed on the connection side of the light guide plate and has a reflector, a first lamp and a second lamp. The first lamp and the second lamp are enclosed by the reflector. The perpendicular distance from the first lamp to the connection side of the light guide plate is greater than that from the second lamp to the connection side of the light guide plate. The reflector is composed of a plurality of curved surfaces to reflect light from the first lamp and the second lamp to the light guide plate. Thus, the light guide plate and the illumination assembly feature reduced thickness.
Preferably, the reflector is composed of an oval surface, a first curved surface, a second curved surface, a third curved surface and a plane surface.
Preferably, the oval surface and the plane surface are connected to the connection side of the light guide plate.
Preferably, the first lamp is disposed within the first curved surface.
Preferably, the second lamp is disposed within the third curved surface.
Preferably, the first curved surface, the second curved surface and the third curved surface are further composed of a plurality of minor curved surfaces, respectively.
Preferably, a plurality of optical dots are formed on the bottom of the light guide plate for absorbing and diffusing the light input to the light guide plate.
Preferably, the reflector is made of stainless steel.
Preferably, the backlight module further comprises an optical film disposed under the light guide plate.
Preferably, the backlight module further comprises a diffusing film disposed on the glass panel.
Preferably, the backlight module further comprises a brightness enhancement film disposed on the diffusing film.
Preferably, the light guide plate is made of acrylic material.
A detailed description will be given by the following embodiments with reference to the accompanying drawings.


REFERENCES:
patent: 5618095 (1997-04-01), Kashima et al.
patent: 6181391 (2001-01-01), Okita et al.
patent: 6390638 (2002-05-01), Miller et al.

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