U.S. patent application number 11/851171 was filed with the patent office on 2008-03-13 for light emitting apparatus and method for the same.
This patent application is currently assigned to MUTUAL-TEK INDUSTRIES CO., LTD.. Invention is credited to Jung-Chien Chang.
Application Number | 20080064131 11/851171 |
Document ID | / |
Family ID | 39170205 |
Filed Date | 2008-03-13 |
United States Patent
Application |
20080064131 |
Kind Code |
A1 |
Chang; Jung-Chien |
March 13, 2008 |
LIGHT EMITTING APPARATUS AND METHOD FOR THE SAME
Abstract
A light emitting apparatus includes a patterned conductive
layer, a light emitting device on the patterned conductive layer,
and a first light diffusion layer. The light emitting device and
the patterned conductive layer are embedded in the first light
diffusion layer. A method of forming such a light emitting
apparatus is also disclosed.
Inventors: |
Chang; Jung-Chien;
(Xinzhuang City, TW) |
Correspondence
Address: |
SNELL & WILMER L.L.P. (Main)
400 EAST VAN BUREN, ONE ARIZONA CENTER
PHOENIX
AZ
85004-2202
US
|
Assignee: |
MUTUAL-TEK INDUSTRIES CO.,
LTD.
Xinzhuang City
TW
|
Family ID: |
39170205 |
Appl. No.: |
11/851171 |
Filed: |
September 6, 2007 |
Current U.S.
Class: |
438/29 ;
257/E33.001; 257/E33.059; 257/E33.074 |
Current CPC
Class: |
G02B 5/02 20130101; G02F
1/133603 20130101; H01L 2224/48227 20130101; H01L 2933/0091
20130101; H01L 2224/48091 20130101; H01L 2924/181 20130101; H01L
2224/48091 20130101; H01L 2924/00012 20130101; H01L 2924/00014
20130101; H01L 2924/181 20130101; G02F 1/133606 20130101; H01L
33/52 20130101 |
Class at
Publication: |
438/29 ;
257/E33.001 |
International
Class: |
H01L 21/00 20060101
H01L021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 12, 2006 |
TW |
95133609 |
Claims
1. A method for forming a light emitting apparatus, comprising:
providing a substrate; forming a patterned conductive layer on said
substrate; disposing a light emitting device on said patterned
conductive layer; and forming a first light diffusion layer
covering said substrate, so that said light emitting device and
said patterned conductive layer are embedded in said first light
diffusion layer.
2. The method according to claim 1, further comprising removing
said substrate to expose said patterned conductive layer after
forming said first light diffusion layer.
3. The method according to claim 2, further comprising forming a
reflective layer on said patterned conductive layer after removing
said substrate.
4. The method according to claim 1, wherein said light emitting
device comprises a light emitting diode.
5. The method according to claim 1, further comprising utilizing a
first injection mold to form a light-transparent layer covering
said light emitting device prior to said step of forming said first
light diffusion layer.
6. The method accordingly to claim 5, wherein said
light-transparent layer is an arc shape structure.
7. The method according to claim 5, wherein said light-transparent
layer is a wave shape structure.
8. The method according to claim 5, wherein said light-transparent
layer comprises a material selected from a group consisting of
epoxy, silicone, acrylic resin, and fluorinated resin.
9. The method according to claim 1, wherein said first light
diffusion layer is formed by utilizing a second injection mold.
10. The method according to claim 9, wherein said first light
diffusion layer is formed with a rough surface defined by utilizing
the second injection mold.
11. The method according to claim 1, further comprising performing
a plasma bombardment process on said first light diffusion layer to
form a rough surface.
12. The method of claim 1, wherein said first light diffusion layer
comprises a material selected from a group consisting of
polycarbonate, acrylate resin, copolymer of methyl acrylate and
styrene, cyclic olefin copolymer, poly ethylene terephthalate and
polystyrene.
13. The method of claim 1, wherein said first light diffusion layer
further includes at least one light diffusion particle therein and
said light diffusion particle comprises a material selected from a
group consisting of TiO.sub.2, SiO.sub.2, acrylate resin,
polystyrene, and the combination thereof.
14. The method of claim 1, further comprising utilizing a third
injection mold to form a prism layer covering said first light
diffusion layer.
15. The method of claim 14, wherein said prism layer comprises a
material selected from a group consisting of polycarbonate,
acrylate resin, copolymer of acrylate and styrene, cyclic olefin
copolymer, poly ethylene terephthalate and polystyrene.
16. The method of claim 14, further comprising forming a second
light diffusion layer covering said first light diffusion layer
prior to said step of forming said prism layer.
17. The method of claim 16, wherein said second light diffusion
layer is formed by an evaporation process.
18. The method of claim 16, wherein said second light diffusion
layer comprises a material selected from a group consisting of
TiO.sub.2, SiO.sub.2, acrylate resin, polystyrene.
19. The method of claim 1 further comprising forming an electronic
device on said patterned conductive layer and embedded in said
first light diffusion layer, wherein said electronic device is
configured to control said light emitting device.
20. The method of claim 2, further comprising a heat dissipation
element contacting an exposed surface of said patterned conductive
layer.
Description
RELATED APPLICATION
[0001] This application claims the right of priority based on
Taiwan Patent Application No. 095133609 entitled "LIGHT EMITTING
APPARATUS AND METHOD FOR THE SAME," filed on Sep. 12, 2006, which
is incorporated herein by reference and assigned to the assignee
hereof.
TECHNICAL FIELD
[0002] The present invention relates to a light emitting apparatus,
and more particularly, to a light emitting apparatus with a light
diffusion layer.
BACKGROUND OF THE INVENTION
[0003] In general, liquid crystal displays require light emitting
apparatus to provide sufficient and uniformly distributed lights
for displaying images, and such a light emitting apparatus is
generally referred to as a backlight module. FIG. 1 illustrates a
schematic view of a conventional backlight module 100. As shown in
FIG. 1, the backlight module 100 includes a light source 110, a
housing 120 covering the light source 110, a reflective layer 121
coated on the housing 120, a diffusion plate 130, and various
optical films 140. The manufacture of the backlight module 100
includes mounting the light source 120 on a predetermined position
of the housing 120, placing the diffusion plate 130 over the light
source 110, and then attaching required optical films 140 on the
light diffusion plate 130.
[0004] Though the conventional light emitting apparatus may provide
sufficient light, its thickness is considerably significant.
Consequently, it is not practical to apply such a bulky light
emitting apparatus to portable electronic devices, which are aimed
to be smaller and lighter. Therefore, there is a need to provide a
light emitting apparatus to fit the urge of modern life.
SUMMARY OF THE INVENTION
[0005] The present invention implements injection mold techniques
to provide a light emitting apparatus with a light source embedded
in a light diffusion layer, so that the thickness of the light
emitting apparatus can be significantly reduced.
[0006] One aspect of the present invention is to provide a light
emitting apparatus including a patterned conductive layer, a light
emitting device on the patterned conductive layer, and a light
diffusion layer. The light emitting device and the patterned
conductive layer are embedded in the light diffusion layer.
[0007] Another aspect of the present invention is to provide a
method of forming a light emitting apparatus including providing a
substrate; forming a patterned conductive layer on the substrate;
disposing a light emitting device on the patterned conductive
layer; and forming a first light diffusion layer covering the
substrate so that the light emitting device and the patterned
conductive layer are embedded in the first light diffusion
layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 illustrates a cross-sectional view of a conventional
light emitting apparatus;
[0009] FIGS. 2A to 2J illustrate cross-sectional views of a process
flow of forming a light emitting apparatus in accordance with a
first embodiment of the present invention;
[0010] FIG. 2K illustrates a bottom view of the structure shown in
FIG. 2I;
[0011] FIG. 2L illustrates a preferred structure by adding a
reflective layer to the stucture shown in FIG. 2J;
[0012] FIGS. 3A to 3C illustrate cross-sectional views of a process
flow of forming a light emitting apparatus in accordance with a
second embodiment of the present invention; and
[0013] FIGS. 4A and 4B illustrate cross-sectional views of a
process flow of forming a light emitting apparatus in accordance
with a third embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] The preferred embodiments of the present invention will now
be described in greater detail by referring to the drawings
accompanied in the present application. It should be noted that the
features illustrated in the drawings are not necessarily drawn to
scale, and similar reference numerals are designated to similar
elements. Descriptions of well-known components, materials, and
process techniques are omitted so as not to unnecessarily obscure
the embodiments of the invention.
[0015] FIGS. 2A to 2J illustrate cross-sectional views of a process
flow of forming a light emitting apparatus in accordance with a
first embodiment of the present invention, and FIG. 2K illustrates
a bottom view of the structure shown in FIG. 2I.
[0016] Referring to FIG. 2A, a substrate 210 is provided, and a
patterned conductive layer 211 is formed on the substrate 210. In
this embodiment, the substrate 210 can be a substrate made of
conductive material, such as a steel plate or a copper plate, and
the thickness of the substrate 210 can be varied as necessary. The
patterned conductive layer 211 can be formed by conventional
techniques, such as lithography, press printing, or screen
printing. For example, a patterned photoresist layer (not shown)
can be formed on the substrate 210 to serve as a mask, and by
electroplating a conductive material on the masked substrate and
removing the patterned photoresist layer after the plating process,
the patterned conductive layer 211 is formed on the substrate 210.
The material of the patterned conductive layer 211 can be copper or
any other suitable conductive material, and the thickness of the
patterned conductive layer 211 is not critical, for example,
typically between about 0.2 mil and about 2 mil.
[0017] Referring to FIG. 2B, a light emitting device 220 is
disposed on a predetermined position of the conductive layer 211
and wire-bonded to electrically couple with the conductive layer
211. In this embodiment, the light emitting device 220 can be a
light emitting diode, and preferably a light emitting diode
chip.
[0018] Referring to FIGS. 2C and 2D, a light-transparent layer 230
is formed to cover the light emitting device 220. The
light-transparent layer 230 can be a spherical or non-spherical
lens covering the light emitting device 220. For example, the
light-transparent layer 230 can be formed by utilizing a first
injection mold 231 covering the light emitting device 220 with a
cavity (A) therein, and then a molding material is injected into
the cavity (A) to form the light-transparent layer 230. Any
light-transparent material suitable for the molding process can be
implemented to form the light-transparent layer 230. For example,
the material of the light-transparent layer 230 can be epoxy,
silicone, acrylic resin, or fluorinated resin, and preferably
silicone. Please note that the profile of the light-transparent
layer 230 is defined by the shape of the cavity (A) created by the
first injection mold 231. As shown in FIG. 2C, the
light-transparent layer 230 is a lampshade like structure, e.g. an
arc structure, and can prevent the light emitting device 220 from
damage in subsequent processes. Alternatively, fluorescent powders
can be added into the light-transparent layer 230 to adjust the
color of light. In this embodiment, the thickness of the
light-transparent layer 230 is smaller than about 0.5 mm, and
preferably between 0.4 mm and 0.2 mm. FIG. 2D illustrates a
structure with the light-transparent layer 230 after the first
injection mold 231 is removed.
[0019] Referring to FIGS. 2E and 2F, a first light diffusion layer
240 is formed covering the substrate 210, so that the
light-transparent layer 230, the light emitting device 220, and the
patterned conductive layer 211 are embedded in the first light
diffusion layer 240. The first light diffusion layer 240 can be
formed in a similar way as the light-transparent layer 230. For
example, the substrate 210 is disposed in a second injection mold
241, and a molding material is injected to form the light diffusion
layer 240. By utilizing the molding technique, the light diffusion
layer 240 is formed over the substrate 210 and covers the
light-transparent layer 230, the light emitting device 220, and the
patterned conductive layer 211, i.e. has the light-transparent
layer 230, the light emitting device 220 and the patterned
conductive layer 211 embedded therein. The light diffusion layer
240 can be made of any suitable material, such as polycarbonate,
acrylate resin, copolymer of methyl acrylate and styrene, cyclic
olefin copolymer, poly ethylene terephthalate and polystyrene etc.,
and preferably cyclic olefin copolymer. Optionally, light diffusion
particles 242 can be added into the first light diffusion layer 240
so as to enhance the light diffusion effect. The light diffusion
particles 242 may include a material selected from a group
consisting of TiO.sub.2, SiO.sub.2, acrylate resin, polystyrene,
and the combination thereof. The amount of light diffusion
particles 242 in the first light diffusion layer 240 is about 1 wt
% to 5 wt %. FIG. 2F illustrates a structure with the light
diffusion layer 240 after the second injection mold 241 is removed.
Similarly, the profile of the light diffusion layer 240 can be
varied by modifying the design of the second injection mold 241. As
shown in FIG. 2E, the second injection mold is designed with a
rough surface 243 facing the space where the first light diffusion
layer 240 is to be formed. And accordingly, the first light
diffusion layer 240 is formed with a rough surface 244
corresponding to the rough surface 243. The rough surface 244 can
enhance the light diffusion effect. Please note that the rough
surface 244 is optionally formed and can be formed by other
techniques, such as plasma bombardment technique, or printing
technique, according to different design needs. For example, the
plasma bombardment process can create a surface of a finer
roughness. Please note that the substrate 210 will be removed in a
later process, so the first light diffusion layer 240 should have a
sufficient thickness to serve as a carrier supporting the patterned
conductive layer 211, the light emitting device 220, the
light-transparent layer 230, and other optical films, if such
exist. For example, in this embodiment, the thickness of the first
light diffusion layer 240 is less than 3 mm, and preferably between
2 mm and 1 mm.
[0020] Referring to FIG. 2G, a second light diffusion layer 250 is
optionally formed to cover the first light diffusion layer 240. In
this embodiment, a material similar to light diffusion particles
242 described above may be deposited on the first light diffusion
layer 240 by physical or chemical evaporation to form the second
light diffusion layer 250. If the first light diffusion layer 240
produces sufficient diffusion effect, the second light diffusion
layer 250 may be omitted.
[0021] Referring to FIGS. 2H and 2I, a prism layer 260 is formed
over the substrate 210 covering the first light diffusion layer 240
and the second diffusion layer 250. Then, the substrate 210 is
removed to expose the patterned conductive layer 211. Similarly,
the prism layer 260 can be formed by utilizing a third injection
mold 261, injecting a molding material, and removing the third
injection mold 261. The prism layer 260 may include a material
selected from a group consisting of polycarbonate, acrylate resin,
copolymer of methyl acrylate and styrene, cyclic olefin copolymer,
poly ethylene terephthalate and polystyrene etc., and preferably
cyclic olefin copolymer. FIG. 2I illustrates a structure with the
prism layer 260 after the first injection mold 261 is removed.
Similarly, the profile of the prism layer 260 may also be defined
by the third injection mold 261 to meet the design needs.
[0022] The structure formed by three injection molds in FIG. 2I
includes the prism layer 260, the second diffusion layer 250, the
first diffusion layer 240, the light-transparent layer 230, the
light emitting device 220, and the patterned conductive layer 211,
which are integrated as the light emitting apparatus. Particularly,
the light emitting device 220 and the patterned conductive layer
211 are embedded in the first diffusion layer 240. Different from
the conventional light emitting apparatus of FIG. 1, the light
emitting apparatus of the present invention eliminates the needs of
the housing 120 and the reflective layer 121 thereon, and
accordingly, the thickness is significantly reduced. Please note
that the term "embedded" indicates that at least a portion of the
light emitting device 220 and at least a portion of the patterned
conductive layer 211 are buried in the first light diffusion layer
240.
[0023] FIG. 2I shows a preferred embodiment that the entire light
emitting device 220 and the patterned conductive layer 211 are
buried in the first light diffusion layer 240, and the bottom
surface of the patterned conductive layer 211 is substantially
coplanar with the bottom surface of the first light diffusion layer
240. The light emitting apparatus of the present invention not only
has the advantage of reduced thickness, but also benefits the
product manufacturers (such as liquid crystal display or mobile
device manufacturers) in the feasibility of assembly and the
simplification of the production flow, in turn, increasing the
productivity.
[0024] Before referring to FIG. 2J, a bottom view of the light
emitting apparatus of FIG. 2I is shown in FIG. 2K. As shown in FIG.
2K, the substrate 210 is removed to expose the patterned conductive
layer 211 so as to facilitate the improvement of heat dissipation.
Furthermore, as shown in FIG. 2J, a heat dissipation element 270,
such as a heat dissipation glue 271 or a heat dissipation plate
272, may optionally contact the exposed surface of the patterned
conductive layer 211 to improve the heat dissipation ability of the
light emitting apparatus.
[0025] FIG. 2L shows another preferred example of the first
embodiment. Different from FIG. 2J, the structure of FIG. 2L
further includes a reflective layer 281 between the bottom surface
of the structure of FIG. 2I and the heat dissipation element 270.
The reflective layer 281 is used for reflecting light toward the
bottom surface of the structure of FIG. 2I so as to prevent the
light from dissipating or being absorbed by the heat dissipation
element 270 or any other components. The reflective layer 281 will
enhance the brightness and the light uniformity of the light
emitting apparatus. The reflective layer 281 can be made of any
suitable reflective materials and the fluorescent materials are
preferred.
[0026] FIGS. 3A to 3C illustrate cross-sectional views of a light
emitting apparatus in accordance with a second embodiment of the
present invention. Different from the first embodiment, an
electronic device 320 is also disposed on the patterned conductive
layer 211 and embedded in the first light diffusion layer 240. The
electron device 320 may be a Zener diode configured to control the
light emitting device 220. FIG. 3A shows the substrate 210 having
the light emitting device 220 and the electronic device 320 thereon
is disposed in a fourth injection mold 321. In this embodiment, a
molding material is injected into only the cavity (A), and the
cavity (B) remains empty of molding material. FIG. 3B illustrates a
structure after the first injection mold 331 is removed. As can be
seen, the light emitting device 220 is covered by the
light-transparent layer 230, and the electronic device 320 remains
exposed. Similarly, the first diffusion layer 240, the second
diffusion layer 250, and the prism layer 260 can be formed on the
structure of FIG. 3B to complete the integrated light emitting
apparatus, as shown in FIG. 3C. Preferably, a reflective layer 281
as aforementioned can be formed on the bottom surface of the
structure of FIG. 3C.
[0027] FIGS. 4A and 4B illustrate cross-sectional views of a light
emitting apparatus in accordance with a third embodiment of the
present invention. Different from the first embodiment, a
light-transparent layer 430 of wave structure is implemented in
this embodiment. As shown in FIG. 4A, a fifth injection mold 431
having a cavity (C) is provided. The cavity (C) includes an uneven
inner surface, such as a wave like surface. The substrate 210 is
disposed in the fifth injection mold 431, and the light emitting
device 220 thereon is accommodated in the cavity (C). Then, a
molding material is injected into the cavity (C), and after the
molding material is cured, the fifth injection mold 431 is removed,
and the wave shape light-transparent layer 430 is formed. The wave
shape light-transparent layer 430 may improve the distribution of
light so as to eliminate the shadow phenomenon caused by the light
emitting device 220. Similarly, the first diffusion layer 240, the
second diffusion layer 250, and the prism layer 260 can be formed
on the light-transparent layer 430 to complete the integrated light
emitting apparatus, as shown in FIG. 4B. Preferably, a reflective
layer 281 as aforementioned can be formed on the bottom surface of
the structure of FIG. 4B.
[0028] The detailed description of the above preferable embodiments
is to describe the technical features and spirit of the present
invention, and the disclosed preferable embodiments are not
intended to limit the scope of the present invention. On the
contrary, the preferable embodiments and their variations or
equivalents all fall within the scope of the present invention.
Although specific embodiments have been illustrated and described,
it will be obvious to those skilled in the art that various
modifications may be made without departing from what is intended
to be limited solely by the appended claims.
* * * * *