U.S. patent application number 11/640368 was filed with the patent office on 2007-05-03 for diffusion sheet and manufacturing method thereof.
Invention is credited to Jen-Huai Chang, Yu-Wei Chang, Jyh Horng Wang.
Application Number | 20070098998 11/640368 |
Document ID | / |
Family ID | 34709551 |
Filed Date | 2007-05-03 |
United States Patent
Application |
20070098998 |
Kind Code |
A1 |
Chang; Jen-Huai ; et
al. |
May 3, 2007 |
Diffusion sheet and manufacturing method thereof
Abstract
A diffusion sheet structure in the direct type backlight module
with anti-UV rays function and its manufacturing method discloses a
diffusion sheet in the backlight module applied to TFT-LCD TV, and
plural layer of the diffusion sheet made by a method of a
multi-layer co-extrusion. The diffusion sheet advocates that while
producing diffusion layer, at least a ultra-violet rays absorption
layer set on the surface of diffusion layer at the same time to
achieve insulating ultra-violet rays directly irradiated on the
diffusion sheet and to avoid yellow and pyrolysis phenomenon
occurred on the diffusion sheet. These results in avoiding the
deviation caused from color temperature and chromaticity coordinate
of TFT-LCD TV because of yellow diffusion sheet, then to achieve
the purpose of improving product quality and materials
lifespan.
Inventors: |
Chang; Jen-Huai; (Yongjing
Shiang, TW) ; Wang; Jyh Horng; (Sansia Township,
TW) ; Chang; Yu-Wei; (Jhongli City, TW) |
Correspondence
Address: |
ROSENBERG, KLEIN & LEE
3458 ELLICOTT CENTER DRIVE-SUITE 101
ELLICOTT CITY
MD
21043
US
|
Family ID: |
34709551 |
Appl. No.: |
11/640368 |
Filed: |
December 18, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10863490 |
Jun 9, 2004 |
|
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11640368 |
Dec 18, 2006 |
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Current U.S.
Class: |
428/423.1 |
Current CPC
Class: |
G02B 6/0065 20130101;
G02B 6/0051 20130101; Y10T 428/31551 20150401 |
Class at
Publication: |
428/423.1 |
International
Class: |
B32B 27/40 20060101
B32B027/40 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 2, 2004 |
TW |
093100100 |
Claims
1. A structure of diffusion sheet in the direct type backlight
module with anti-UV rays comprising: at least a ultra-violet rays
absorption layer; and a diffusion layer; wherein said ultra-violet
rays absorption layer located at least a surface of said diffusion
layer.
2. The structure of diffusion sheet in the direct type backlight
module with anti-UV rays as claimed in claim 1, wherein said
ultra-violet rays absorption layer comprises a resin and a
ultra-violet rays absorbent.
3. The structure of diffusion sheet in the direct type backlight
module with anti-UV rays as claimed in claim 2, wherein said resin
is selected from one of transparency acrylic resin, PMMA
(Polymethyl Methacrylate), MS (MMA/Styrene Copolymer) and PC
(Polycarbonate), COC (Cycle Olefin Copolymer).
4. The structure of diffusion sheet in the direct type backlight
module with anti-UV rays as claimed in claim 1, wherein the
thickness of said ultra-violet rays absorption layer is 1.about.200
.mu.m.
5. The structure of diffusion sheet in the direct type backlight
module with anti-UV rays as claimed in claim 1, wherein said
diffusion layer comprises plural light diffusion particles and a
substrate.
6. The structure of diffusion sheet in the direct type backlight
module with anti-UV rays as claimed in claim 5, wherein said light
diffusion particles is selected from one of organic and inorganic
materials.
7. The structure of diffusion sheet in the direct type backlight
module with anti-UV rays as claimed in claim 6, wherein said light
diffusion particles is selected from one of acrylic resin, Titanium
Dioxide (TiO.sub.2) and Silicon Dioxide (SiO.sub.2), Silicon.
8. The structure of diffusion sheet in the direct type backlight
module with anti-UV rays as claimed in claim 5, wherein said
substrate is selected from one of acrylic resin, PMMA (Polymethyl
Methacrylate), MS (MMA Styrene Copolymer) and PC (Polycarbonate),
COC (Cycle Olefin Copolymer).
9. A method of manufacturing diffusion sheet in the direct type
backlight module with anti-UV rays comprising the steps of:
extruding a diffusion layer by adding a plurality of light
diffusion particles into a substrate and using a first extruder;
extrusion a ultra-violet rays absorption layer by adding a
ultra-violet rays absorbent into a resin and using a second
extruder; taking said ultra-violet rays absorption layer to touch
at least one surface of said diffusion layer by a multi-layer
T-die; co-extruding said diffusion layer and said ultra-violet rays
absorption layer to form a plate structure of light diffusion sheet
with anti-yellow and well dimensional stability.
10. The structure of diffusion sheet in the direct type backlight
module with anti-UV rays as claimed in claim 9, wherein the content
of said light diffusion particles is 1.about.10 percent of said
substrate.
11. The structure of diffusion sheet in the direct type backlight
module with anti-UV rays as claimed in claim 9, wherein the
increment of said ultra-violet rays absorbent is 1 percent of said
resin.
12. A structure of a diffusion sheet in a direct type backlight
module with ultraviolet ray resistance, comprising: a diffusion
layer formed by light diffusing particulates disbursed in a first
resin, said diffusion layer having first and second opposing sides;
and at least one ultraviolet ray absorption layer overlaying said
first side of said diffusion layer, said ultraviolet ray absorption
layer being formed by an ultraviolet ray absorbent disbursed in a
second resin.
13. The structure of a diffusion sheet as claimed in claim 12,
wherein said first and second resin acrylic resin.
14. The structure of a diffusion sheet as claimed in claim 12,
wherein said light diffusion particulates are formed by
particulates of silicon.
15. The structure of a diffusion sheet as claimed in claim 12,
wherein said light diffusion particulates are formed by
particulates of titanium dioxide (TiO.sub.2).
16. The structure of a diffusion sheet as claimed in claim 12,
wherein said light diffusion particulates are formed by
particulates of silicon dioxide (SiO.sub.2).
17. The structure of a diffusion sheet as claimed in claim 12,
further comprising a second ultraviolet ray absorption layer
overlaying said second side of said diffusion layer, said second
ultraviolet ray absorption layer being formed by said ultraviolet
ray absorbent disbursed in said second resin.
18. A method of manufacturing a diffusion sheet in a direct type
backlight module with ultraviolet ray resistance, comprising the
steps of: blending a plurality of light diffusion particles into a
first resin using a first extruder; blending an ultraviolet ray
absorbent into a second resin using a second extruder; coupling an
output of each of said first extruder and said second extruder to a
multi-layer T-die; co-extruding a diffusion layer output from said
first extruder with at least one ultraviolet absorption layer on at
least one side of said diffusion layer and output from said second
extruder to form a plate structure of a light diffusion sheet with
anti-yellowing and dimensional stability characteristics.
Description
RELATED APPLICATIONS
[0001] This application is a Continuation patent application of
co-pending application Ser. No. 10/863,490, filed on 9 Jun.
2004
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a diffusion sheet structure
in the direct type backlight module with anti-UV rays function and
its manufacturing method, which especially points at a diffusion
sheet in the backlight module applied to TFT-LCD TV. This invention
explores a diffusion sheet with a ultra-violet rays absorption
layer avoid yellow and pyrolysis phenomenon and finally to improve
product quality and materials lifespan.
[0004] 2. Description of the Prior Art
[0005] Since TFT-LCD has been invented, all kinds of colour monitor
have been widely applied in the daily life, such as notebook, PC
monitor, colour mobile phone, PDA, and LCD TV etc., which have
accordingly replaced conventional display such as CRT, TN and STN.
An example of TFT-LCD TV, TFT-LCD TV being accordingly accepted by
the consumers is because of liquid crystal panel producing
technology improvement, such as short response time, high
resolution, and higher yield of large panel. Besides, higher
brightness of backlight module is also one of the main factors.
[0006] The larger size of TFT-LCD TV requires more, the higher
brightness of one requires more. Normally the brightness of TFT-LCD
TV requires 800-1200 Cd/m.sup.2, moreover, the uniform backlight
module technology through light guide panel by the traditional edge
light source can not satisfy the requirements of TFT-LCD TV.
Therefore, high brightness of direct type backlight source is
occurred.
[0007] In order to enhance the brightness of TFT-LCD TV, it is
necessary to increase the quantity of CCFL (Cold Cathode
Fluorescent Lamp) and the edge light source is changed into direct
type light source, shown as FIG. 1, which is a schematic diagram of
the prior art of direct type backlight module. As FIG. 1 shown,
said direct type backlight module 1' comprises of a reflector 10',
plural light source 20' and a diffusion sheet 30'. In order to
avoid lamp mark, the light guide panel is required to be replaced
by diffusion sheet to uniformly disperse the brightness of light
source. The thickness of diffusion sheet is controlled in a range
of 2 to 3 mm, the thickness of relative light guide panel is a
range of 3 to 12 mm which having a large capability of reducing
materials cost and to achieve the purpose of weight. The present
diffusion sheet is mainly composed of PMMA (Polymethyl
Methacrylate), MS (MMA/Styrene Copolymer), PC (Polycarbonate), and
COC (Cycle Olefin Copolymer). and adding light diffusion particles
in the transparent substrate to achieve uniform light.
[0008] The main strength of diffusion sheet in the composition of
PMMA is well optical transmittance and yellow-resistance, however,
the water absorption ratio of PMMA is in a range of 0.3 to 0.4%
which resulted in a defect of warp and bad dimensional stability on
the large TV. The light transmittance of MS and PC is small 2 to 3%
than PMMA, but MS and PC has good performance on high temperature
resistance and dimensional stability. The main defect is that MS
and PC under irradiation of UV rays result in the problem of
yellow. If the diffusion sheet in the composition of PC is long
time irradiated under CCFL, then the problems of yellow will occur
and result in colour temperature and chromatic aberration of panel.
This problem is the main reason why diffusion sheet with PC
materials cannot be extensively applied.
[0009] Therefore, providing a novel diffusion sheet structure in
the direct type backlight module with anti-UV rays function and its
manufacturing method for the aforesaid problems can not only
improve the defects of yellow of the conventional diffusion sheet
which resulted in deviation, but also can be simplified the
process. Based on the inventor engaging on the research and develop
and sales experiences for the related products for many years, the
inventor finally proposes a method to improve the aforementioned
problems for diffusion sheet structure in the direct type backlight
module with anti-UV rays function and its manufacturing method,
according to his professional background.
SUMMARY OF THE INVENTION
[0010] The primary purpose of the present invention is to provide a
diffusion sheet structure in the direct type backlight module with
anti-UV rays function and its manufacturing method, which using a
ultra-violet rays absorption layer sets on a diffusion layer to
achieve insulating ultra-violet rays directly irradiated on the
diffusion and to avoid yellow and pyrolysis phenomenon occurred on
the diffusion sheet. Furthermore, to avoid the deviation caused
from color temperature and chromaticity coordinate of TFT-LCD TV
because of yellow diffusion sheet, then to achieve the purpose of
improving product quality and materials lifespan.
[0011] In order to perform the aforementioned purposes, efficiency
and characteristics of each, the present invention explores that
diffusion sheet structure in the direct type backlight module with
anti-UV rays function and its manufacturing method, which is a
diffusion sheet in the backlight module applied to TFT-LCD TV, and
plural layer of the diffusion sheet made by a method of a
multi-layer co-extruder. The present invention advocates that while
producing diffusion sheet, at least a ultra-violet rays absorption
layer set on the surface of diffusion sheet at the same time to
achieve insulating ultra-violet rays directly irradiated on the
diffusion sheet and to avoid yellow and pyrolysis phenomenon
occurred on the diffusion sheet. These results in avoiding the
deviation caused from color temperature and chromaticity coordinate
of TFT-LCD TV because of yellow diffusion sheet, then to achieve
the purpose of improving product quality and materials lifespan.
For manufacturing technology, it is mainly using a co-extruder to
produce multi-layer structure of diffusion sheet which is based on
the diffusion sheet that a substrate adding a light diffusion
materials, and in a range of 10 to 500 .mu.m thickness of sheet is
co-extruded at least on one side of diffusion sheet at the same
time, then adding a transparent resin of UV rays absorbent to form
at least one side of UV rays absorbent on said diffusion sheet,
therefore, at least one side of anti-UV rays of diffusion sheet is
formed.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is an illustrated diagram of the direct type
backlight module of the prior art;
[0013] FIG. 2 is a schematic diagram of the preferred embodiment of
the present invention;
[0014] FIG. 2A is a schematic diagram of another preferred
embodiment of the present invention;
[0015] FIG. 3 is flowchart of the preferred embodiment of the
present invention; and
[0016] FIG. 4 is a graphic of the preferred embodiment of the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] In order to clearly express and explore the feature
characteristics and efficiency of the present invention for the
committee of patent, the preferred embodiment and detailed
description is as below.
[0018] In order to improve the yellow problems of the prior art
which is resulted from UV rays for diffusion sheet of direct type
backlight module that applied to TFT-LCD TV, the present invention
proposes that setting a transparent substrate with a UV rays
absorbent on the surface of diffusion sheet, the thickness of UV
rays absorption can be controlled in a range of 1 to 200 .mu.m. The
present invention also proposes a process of co-extrusion While
diffusion sheet is extruded by the main extruder, the sub-extruder
extrudes UV rays absorption layer at the same time at least on one
side of said diffusion sheet to achieve the effect of insulating UV
rays directly irradiating on diffusion sheet to avoid yellow
problem.
[0019] FIG. 2 is a schematic diagram of the preferred embodiment of
the present invention that explores diffusion sheet structure of
the direct type backlight module applying to TFT-LCD TV. As shown
in FIG. 2, the present invention explores a structure of diffusion
sheet of the direct type backlight module with anti-UV rays
function. Said diffusion sheet 10 comprises at least a UV rays
absorption layer 100 and a diffusion sheet 110, wherein said UV
rays absorption layer 100 is located at least one side of said
diffusion sheet 110, wherein said UV rays absorption layer 100 is a
UV rays 200 to insulate UV rays directly irradiating on said
diffusion sheet 10 to avoid the problems of yellow and pyrolysis
occurred on diffusion sheet.
[0020] Wherein said UV rays absorption layer 100 comprises a resin
102 which is selected from a transparent acrylic resin and a UV
rays absorbent, the thickness of said UV rays absorption layer 100
is in a range of 10 to 200 .mu.m. Said diffusion sheet 110
comprises pural light diffusion particles 112 which is selected
from one of organic and inorganic materials, such as acrylic resin,
Titanium Dioxide (TiO.sub.2), Silicon Dioxide (SiO.sub.2), and
Silicon and its particle size is in a range of 1.about.50 .mu.m.
And a substrate 114 which is selected from one of acrylic resin,
PMMA (Polymethyl Methacrylate), MS (MMA Styrene Copolymer), PC
(Polycarbonate) and Cyclo Olefin Copolymer (COC).
[0021] Moreover, FIG. 2A is a schematic diagram of another
preferred embodiment of the present invention that explores
diffusion sheet structure. As shown in FIG. 2, the present
invention explores that said diffusion sheet 10, wherein said UV
rays absorption layer 110 can be located on the top and bottom of
said diffusion sheet 120.
[0022] FIG. 3 is flowchart of the preferred embodiment of the
present invention that explores a manufacturing process of
diffusion sheet. As shown in FIG. 3, the present invention explores
that a method of manufacturing diffusion sheet in the direct type
backlight module with anti-UV rays comprising the steps of: [0023]
Step S110: extruding a diffusion layer by adding a plurality of
light diffusion particles into a substrate and using a first
extruder; [0024] Step S120: extruding a ultra-violet rays
absorption layer by adding a ultra-violet rays absorbent into a
resin and using a second extruder; [0025] Step S130: taking said
ultra-violet rays absorption layer to touch at least one surface of
said diffusion layer by a multi-layer T-die; [0026] Step S140:
co-extruding said diffusion layer and said ultra-violet rays
absorption layer to form a plate structure of light diffusion sheet
with anti-yellow and well dimensional stability.
[0027] Among step 110, the content of said light diffusion
particles is 10 percent of said substrate. Among step 120, the
increment of said UV rays absorbent is 1 to 5% of said resin.
[0028] Finally, FIG. 4 is a graphic of the preferred embodiment of
the present invention that explores diffusion sheet. As shown in
FIG. 4, the present invention explores that steps of a diffusion
sheet and its manufacturing method. Firstly, it is mainly using the
first extruder 40 adding 10 percent of PMMA light diffusion
particles 20 of PC resin 30 to extrude a diffusion sheet 50.
Secondly, it is using the second extruder 80 adding 1 to 5% of UV
rays absorbent 60 of transparent resin layer 70 to extrude a UV
rays absorption layer 90. Thirdly, said UV rays absorption layer 90
is adhered on the top and bottom of diffusion layer 50 through
multi-layer T-die 95. Finally, said PC diffusion layer 50 and at
least a UV rays absorption layer 90 co-extrude a diffusion sheet 98
with plate structure of yellow-resistance and well dimensional
stability.
[0029] Therefore, the present invention is related to a diffusion
sheet and its manufacturing method which a diffusion sheet of
backlight module applied to TFT-LCD TV that using a method of
multi-layer co-extrusion molding technology produces plural layer
diffusion sheet. The present invention is that while producing
diffusion sheet of direct type backlight module of TFT-LCD TV, at
least a ultra-violet rays absorption layer set on the surface of
diffusion sheet at the same time to achieve insulating ultra-violet
rays directly irradiated on the diffusion and to avoid yellow and
pyrolysis phenomenon occurred on the diffusion sheet. These results
in avoiding the deviation caused from color temperature and
chromaticity coordinate of TFT-LCD TV because of yellow diffusion
sheet, then to achieve the purpose of improving product quality and
materials lifespan.
[0030] While certain preferred embodiments of the present invention
have been disclosed in detail, it is to be understood that various
modifications may be adopted without departing from the spirit of
the invention or scope of the following claims.
* * * * *