U.S. patent application number 11/433093 was filed with the patent office on 2007-06-28 for backlight module with a heat conductive block.
This patent application is currently assigned to AU Optronics Corp.. Invention is credited to Chi-chen Cheng, Chin-kun Hsieh, Cheng-chih Lai, Chi-chung Lo, Meng-chai Wu.
Application Number | 20070147080 11/433093 |
Document ID | / |
Family ID | 38193478 |
Filed Date | 2007-06-28 |
United States Patent
Application |
20070147080 |
Kind Code |
A1 |
Wu; Meng-chai ; et
al. |
June 28, 2007 |
Backlight module with a heat conductive block
Abstract
A backlight module includes a bezel having at least one edge, a
circuit board, one or more light emitting diodes connected to the
circuit board for emitting light. Each light emitting diode has a
light axis which is neither parallel nor vertical to the edge of
the bezel. The backlight module utilizes a heat conductive block
disposed between the bezel and the light emitting diode for
transferring heat generated by the light emitting diode to the
bezel.
Inventors: |
Wu; Meng-chai; (Jhubei City,
TW) ; Lo; Chi-chung; (Yongjing Township, TW) ;
Hsieh; Chin-kun; (Hsinchu City, TW) ; Lai;
Cheng-chih; (Changhua City, TW) ; Cheng;
Chi-chen; (Ershuei Township, TW) |
Correspondence
Address: |
MADSON & AUSTIN;GATEWAY TOWER WEST
SUITE 900
15 WEST SOUTH TEMPLE
SALT LAKE CITY
UT
84101
US
|
Assignee: |
AU Optronics Corp.
|
Family ID: |
38193478 |
Appl. No.: |
11/433093 |
Filed: |
May 12, 2006 |
Current U.S.
Class: |
362/612 |
Current CPC
Class: |
F21V 29/87 20150115;
F21V 29/89 20150115; G02F 1/133628 20210101; F21V 29/70 20150115;
F21Y 2115/10 20160801 |
Class at
Publication: |
362/612 |
International
Class: |
F21V 7/04 20060101
F21V007/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 23, 2005 |
TW |
094146287 |
Claims
1. A backlight module, comprising: a bezel having at least one
edge; a circuit board; one or more light emitting diodes connected
to the circuit board, each light emitting diode comprising a light
axis, wherein the light axis of each light emitting diode is
neither parallel nor vertical to the edge of the bezel; and a
non-rectangle heat conductive block disposed between the bezel and
the light emitting diode, for transferring heat generated by the
light emitting diode to the bezel.
2. The backlight module of claim 1, wherein the bezel is made of
metal.
3. The backlight module of claim 1, wherein the circuit board is a
flexible print circuit board.
4. The backlight module of claim 1, wherein the non-rectangle heat
conductive block is made of metal.
5. The backlight module of claim 1, wherein the non-rectangle heat
conductive block, the circuit board, and the bezel are adhered with
a high polymer having high thermal conductivity.
6. The backlight module of claim 1, wherein the non-rectangle heat
conductive block is attached to the bezel.
7. A liquid crystal display incorporating the backlight module of
claim 1.
8. The backlight module of claim 1, further comprising a light
guide plate with a patterned surface.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a backlight module, and
more particularly, to a backlight module capable of arising heat
dissipation.
[0003] 2. Description of the Related Art
[0004] A backlight module is a key component of a liquid crystal
display (LCD). The purpose of the backlight module is to provide a
sufficient-brightness and an even-distribution of light on surface
to the LCD panel. Because the LCD is widely used in various
electronic products such as monitors for notebook computers,
digital cameras, and projectors, the demand for the backlight
module has increased tremendously.
[0005] In addition to cold cathode fluorescent lamps (CCFLs), light
emitting diodes are increasingly used in medium and large size
liquid crystal displays. Please refer to FIG. 1, which shows a
prior art backlight module 10 having a plurality of light emitting
diodes disposed on a bezel. Conventionally, the plurality of LEDs
12 are disposed at the sides of bezel 16 and emit light beams upon
receiving driving signals from a driver (not shown) via a pin 18.
An arrow A indicates a direction of light axis of the LED 12. A
greater power LED emits higher brightness and generates more heat
as well. In order to promptly dissipate generated heat, a
traditional way is to position the LED 12 on a metal core printed
circuit board (MCPCB) 14. The generated heat is rapidly transferred
to bezel 16 and is therefore dissipated by means of air convection.
In addition, for more efficient heat dissipation, both the metal
core printed circuit board (MCPCB) 14 and bezel 16 are made of
metal with high thermal conductivity.
[0006] With a rapid development of LED manufacturing, maximum
luminance provided for new LEDs is greater. Certainly, using new
LEDs can reduce the number of LEDs used in a backlight module,
thereby reducing the cost. Nevertheless, luminance of the LED is
inverse proportion to its operating temperature and thus shortens
the life span of the LED, and how to improve the heat dissipation
in order to lower operating temperature of the LED is a main goal
for backlight module manufacturers.
SUMMARY OF INVENTION
[0007] It is therefore an objective of the claimed invention to
provide a backlight module utilizing a heat conductive block
positioned between a bezel and an LED to increase LED's contact
area against the bezel, conducive to heat dissipation.
[0008] Briefly summarized, a backlight module includes a bezel
having at least one edge, a circuit board, one or more light
emitting diodes connected to the circuit board for emitting light.
Each light emitting diode has a light axis which is neither
parallel nor vertical to the edge of the bezel. The backlight
module utilizes a heat conductive block disposed between the bezel
and the light emitting diode for transferring heat generated by the
light emitting diode to the bezel.
[0009] An advantage of the present invention is to provide a heat
conductive block positioned between the LED and the bezel, which
serves as a heat-transferring bridge between the LED and the bezel.
For the LED at the corner of the bezel, since the heat conductive
block contacts the edge and the bottom surfaces of the bezel, heat
generated by the LED is able to be dissipated quickly through the
heat conductive block.
[0010] These and other objectives of the claimed invention will no
doubt become obvious to those of ordinary skill in the art after
reading the following detailed description of the preferred
embodiment that is illustrated in the various figures and
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows a prior art backlight module having a plurality
of light emitting diodes disposed on a bezel.
[0012] FIG. 2 shows a diagram of a backlight module according to
the present invention.
[0013] FIG. 3 is a partially enlarged diagram of the backlight
module depicted in FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] Please refer to FIGS. 2 and 3. FIG. 2 shows a diagram of a
backlight module 20 according to the present invention, and FIG. 3
is a partially enlarged diagram of the backlight module 20 depicted
in FIG. 2. The backlight module 20 comprises a bezel 26 and a
plurality of light emitting diodes (LEDs) 22 disposed at the
corners of the bezel 26. A bottom surface 32 of the bezel 26 is
used for positioning such optical components as a light guide
plate, a diffusion sheet, and a brightness enhancement film, for
simplicity, not shown in FIG. 2. Also, the plurality of light
emitting diodes (LEDs) 22 is disposed on a circuit board 24. A heat
conductive block 30 is positioned between the circuit board 24 and
the bezel 26. Both the heat conductive block 30 and the bezel 26
are made of metal (e.g. aluminum) or other materials having high
thermal conductivity.
[0015] When the LED 22 emitting light triggered by a driver (not
shown) via a pin 28, heat is generated. The emitted light is guided
by a patterned surface of a light guide plate (not shown) to a
liquid crystal panel, while the generated heat is transferred to
bezel 26 via a circuit board 24 and a heat conductive block 30. In
addition, the bezel 26 contacting the heat conductive block 30 in
areas 42 and 44, as well as a contact area between the bottom of
surface 32 of bezel 26 and the heat conductive block 30. Compared
with the prior art backlight module of FIG. 1, heat generated from
the LED 22 is more quickly dissipated by air convection through
larger contact areas between the bezel 26 and the heat conductive
block 30.
[0016] Preferably, the circuit board 24 is a flexible print circuit
board (PCB) capable of being laid on the bezel 26.
[0017] LED 22 is positioned at the corner of the bezel 26, and is
neither vertical nor parallel to the edges of the bezel 26. In
other words, the light axis B of the LED 22 is neither vertical nor
parallel to the edges of the bezel 26 where the light axis
indicates a median of the maximum luminance region of the LED. In
doing so, a fewer number of the LED 22 positioned at the corner of
the bezel 26 is sufficient for providing the required brightness
for the visible active area of a liquid crystal display.
[0018] Preferably, the solid heat conductive block 30 is made of a
metal with high thermal conductivity, and is not shaped as
rectangular. For better heat dissipating efficiency, the heat
conductive block 30 is affixed and attached to the bezel 26 to
minimize the gap between the heat conductive block 30 and bezel 26.
Furthermore, the heat conductive block 30, the circuit board 24,
and the bezel 26, are adhered with a high polymer having high
thermal conductivity eliminating air gap therebetween.
[0019] The present invention backlight module is for use in liquid
crystal displays that use the LED as a light source.
[0020] To sum up, the LED of the present invention backlight module
is arranged at the edge of the bezel, and the alignment of the LED
is neither vertical nor parallel to the edge of the bezel. In
addition, the present backlight module invention uses a heat
conductive block positioned between the LED and the bezel to
increase the contact areas between the bezel and the heat
conductive block, thereby causing better heat dissipating
efficiency. As to the LED disposed at the corner of the bezel,
heat-dissipating efficiency is improved because of the heat
conductive block directly contacting the edge surfaces and bottom
surface of the bezel.
[0021] Although the present invention has been explained by the
embodiments shown in the drawings described above, it should be
understood to the ordinary skilled person in the art that the
invention is not limited to the embodiments. For example, the
number of LEDs used depends on the design demand, and two or more
LEDs which are not parallel or vertical to either edges of the
bezel are also allowed.
[0022] Although the present invention has been explained by the
embodiments shown in the drawings described above, it should be
understood to the ordinary skilled person in the art that the
invention is not limited to the embodiments, but rather the various
changes or modifications thereof are possible without departing
from the spirit of the invention. For example, in addition to the
metal used in the aforementioned invention, the bezel and the
circuit board are also made of any material with high thermal
conductivity.
[0023] The present invention has been described with reference to
certain preferred and alternative embodiments which are intended to
be exemplary only and not limited to the full scope of the present
invention as set forth in the appended claims. Accordingly, the
scope of the invention shall be determined only by the appended
claims and their equivalents.
* * * * *