U.S. patent application number 14/108283 was filed with the patent office on 2014-04-17 for high efficiency light emitting diode device.
This patent application is currently assigned to WALSIN LIHWA CORPORATION. The applicant listed for this patent is WALSIN LIHWA CORPORATION. Invention is credited to CHUNG-I CHIANG, CHING-HUAN LIAO, CHUAN-FA LIN.
Application Number | 20140103382 14/108283 |
Document ID | / |
Family ID | 47596668 |
Filed Date | 2014-04-17 |
United States Patent
Application |
20140103382 |
Kind Code |
A1 |
CHIANG; CHUNG-I ; et
al. |
April 17, 2014 |
HIGH EFFICIENCY LIGHT EMITTING DIODE DEVICE
Abstract
A light emitting diode device is provided. The light emitting
diode device comprises a light emitting diode element, an
encapsulation layer, and a plurality of pillars. The encapsulation
layer is disposed on the light emitting diode element, and the
pillars are disposed on the encapsulation layer. The pillars are
formed by a light transmissible material.
Inventors: |
CHIANG; CHUNG-I; (Taoyuan
County, TW) ; LIN; CHUAN-FA; (Taoyuan County, TW)
; LIAO; CHING-HUAN; (Taoyuan County, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
WALSIN LIHWA CORPORATION |
Yan-Mei City |
|
TW |
|
|
Assignee: |
WALSIN LIHWA CORPORATION
Yang-Mei City
TW
|
Family ID: |
47596668 |
Appl. No.: |
14/108283 |
Filed: |
December 16, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13562024 |
Jul 30, 2012 |
8643273 |
|
|
14108283 |
|
|
|
|
61513658 |
Jul 31, 2011 |
|
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Current U.S.
Class: |
257/98 |
Current CPC
Class: |
H01L 33/52 20130101;
H01L 33/46 20130101; H01L 2933/0083 20130101; H01L 33/58 20130101;
H01L 33/507 20130101 |
Class at
Publication: |
257/98 |
International
Class: |
H01L 33/52 20060101
H01L033/52; H01L 33/58 20060101 H01L033/58 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 22, 2012 |
TW |
101122518 |
Claims
1. A light emitting diode device, comprising: a light emitting
diode element; an encapsulation layer disposed surrounding the
light emitting diode element; and a plurality of pillars disposed
on the encapsulation layer, wherein the pillars are formed by a
light transmissible material.
2. The light emitting diode device according to claim 1, wherein
the encapsulation layer has a first refractive index, and the
pillars have a second refractive index smaller than or equal to the
first refractive index.
3. The light emitting diode device according to claim 2, wherein
the second refractive index have a gradient refractive index
gradually decreased along a direction from the part near the
encapsulation layer to the part departing from the encapsulation
layer.
4. The light emitting diode device according to claim 1, wherein
the pillars are regularly or irregularly disposed on the
encapsulation layer and are spaced apart from one another.
5. The light emitting diode device according to claim 1, wherein
the pillars are circular pillars, elliptical pillars or polygonal
pillars.
6. The light emitting diode device according to claim 1, wherein
cross-sectional areas of the pillar are gradually decreased or
increased along a direction from a near part of the encapsulation
layer to a departing part of the encapsulation layer.
7. The light emitting diode device according to claim 1, wherein a
width of the pillars is between 1 and 500 .mu.m, and a height of
the pillars is between 10 and 500 .mu.m.
8. The light emitting diode device according to claim 1, further
comprising a plurality of fluorescent particles distributed within
the encapsulation layer.
9. The light emitting diode device according to claim 1, further
comprising a plurality of fluorescent particles disposed between
the encapsulation layer and the pillars.
Description
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/562,024 filed Jul. 30, 2012, now pending,
which claims the benefit of U.S. provisional application Ser. No.
61/513,658, filed Jul. 31, 2011, and the benefit of Taiwan
application Serial No. 101122518, filed Jun. 22, 2012, the subject
matters of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates in general to a light emitting diode
device, and more particularly to a light emitting diode device
having a plurality of pillar structures on the surface of the
packaging layer to increase the light emitting efficiency.
[0004] 2. Description of the Related Art
[0005] Along with the advance in the display technology, the
research and development on various displays have rapidly
developed, and the requirements on the functions and features of
the displays are also getting higher and higher. How to apply
phosphor to the light emitting diode display has become a focus in
the research of the display.
[0006] Fluorescent powders are often used in the light emitting
diode for the transformation of the light. Particularly,
fluorescent powders are capable of absorbing the light emitted by a
light emitting diode light source and transforming the absorbed
light into a light with other wavelength. The light emitting diode
may use suitable types of fluorescent powders, and the light
transformed by the fluorescent powders may be mixed with the light
emitted by a light source to produce a light different from the
original light. For example, the light emitting diode may emit a
white light.
[0007] However, since the refractive index of the encapsulation or
the fluorescent colloidal of the light emitting diode is different
from that of the air, a part of the light emitted by the light
emitting diode will be total internal reflected after the light is
emitted from encapsulation, resulting in energy loss of the light,
which deteriorates the light emitting efficiency of the light
emitting diode. Therefore, how to provide a light emitting diode
element with superior light emitting efficiency has become a
prominent task for the industries.
SUMMARY OF THE INVENTION
[0008] The invention is directed to a light emitting diode device.
The pillars are disposed on the encapsulation layer, such that the
light emitting efficiency of the light emitting diode device is
effectively increased.
[0009] According to an embodiment of the present invention, a light
emitting diode device is provided. The light emitting diode device
comprises a light emitting diode element, an encapsulation layer,
and a plurality of pillars. The encapsulation layer is disposed on
the light emitting diode element, and the pillars are disposed on
the encapsulation layer. The pillars are formed by a light
transmissible material.
[0010] The above and other aspects of the invention will become
better understood with regard to the following detailed description
of the preferred but non-limiting embodiment(s). The following
description is made with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1A shows a schematic diagram of a light emitting diode
device according to an embodiment of the invention;
[0012] FIG. 1B shows a partial diagram of the light emitting diode
device of FIG. 1A;
[0013] FIG. 2 shows a partial enlargement of the light emitting
diode device of FIG. 1B;
[0014] FIGS. 3A-3B show partial diagrams of the pillars of a light
emitting diode device according to an embodiment of the
invention;
[0015] FIG. 4 shows a schematic diagram of a light emitting diode
device according to another embodiment of the invention
[0016] FIG. 5 shows a schematic diagram of a light emitting diode
device according to an alternate embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] A light emitting diode device is disclosed in a number of
embodiments below. The pillars are disposed on the encapsulation
layer such that the light emitting efficiency of the light emitting
diode device is effectively increased. However, the detailed
structures disclosed in the embodiments below are for
exemplification purpose only not for limiting the scope of
protection of the invention. Anyone who is skilled in the
technology of the invention will be able to modify or change the
details of the detailed structures to fit the needs in practical
implementations.
[0018] FIG. 1A shows a schematic diagram of a light emitting diode
device according to an embodiment of the invention. As shown in
FIG. 1A, the light emitting diode device 100 comprises a light
emitting diode element 110, an encapsulation layer 120, and a
plurality of pillars 130. The encapsulation layer 120 is disposed
on and surrounding the light emitting diode element 110, and the
pillars 130 are disposed on the encapsulation layer 120. The
pillars 130 are formed by a light transmissible material, such as
transparent or translucent materials. The pillars 130 are disposed
on the encapsulation layer 120, such that the light emitting
surface of the light emitting diode device 100 is a
three-dimensional geometric structure instead and not a
two-dimensional plane anymore, so as to the amount of the total
internal reflection in the encapsulation layer 120 is reduced. In
other words, when the light emitted from the encapsulation layer
120 is increased, the light emitting efficiency of the light
emitting diode device 100 is also increased.
[0019] FIG. 1B shows a partial diagram of the light emitting diode
device of FIG. 1A. As shown in FIG. 1B, the light L emitted by the
light emitting diode element 110 passes through the encapsulation
layer 120 and the pillars 130 and enters the air. The light L
generates various incident angles and refraction angles when
passing through different interfaces. In the present embodiment,
the material of the encapsulation layer 120 may be the same with or
different from that of the pillars 130.
[0020] In an embodiment, the encapsulation layer 120 has a first
refractive index, and the pillars 130 have a second refractive
index. In an embodiment, the first refractive index is equal to the
second refractive index if the material of the encapsulation layer
120 is the same with that of the pillars 130, and hence, an
incident angle .theta.1 and an emitting angle .theta.2 of the light
L with respect to the surface 120a of the encapsulation layer 120
are equal to each other. In another embodiment, as shown in FIG.
1B, the first refractive index and the second refractive index are
different from each other if the material of the encapsulation
layer 120 is different from that of the pillars 130, and hence, the
incident angle .theta.1 and the emitting angle .theta.2 of the
light L with respect to the surface 120a of the encapsulation layer
120 are different from each other. The light L enters the air via
the side wall of the pillars 130 and generates a light L1. An angle
.theta.3 between the light L1 and the side wall of the pillars 130
is different from the emitting angle .theta.2 of the light L. As
shown in FIG. 1B, the light L is emitted via the side wall of the
pillars 130 when the light L emitted by the light emitting diode
element 110 proceeds to the surface 120a of the encapsulation layer
120, even if the incident angle .theta.1 of the light L with
respect to the surface 120a is larger than the critical angle. When
the light L1 is emitted via the side wall of the pillars 130, the
light emitting pattern of the light emitting diode device 100 is
changed, the light emitting angle of the light emitting diode
device 100 is increased, and the light emitting efficiency of the
light emitting diode device 100 is improved. In comparison to the
light emitting efficiency of the light emitting diode device in an
embodiment without the disposition of the pillars, the light
emitting efficiency of the light emitting diode device 100 is
increased by about 10-15% in the present embodiment in which the
pillars 130 are disposed on the encapsulation layer 120.
[0021] In an embodiment, the first refractive index of the
encapsulation layer 120 is larger than or equal to the second
refractive index of the pillars 130, and the light can be
effectively emitted from the pillars 130 when the first refractive
index is larger than or equal to the second refractive index. In
another embodiment, the pillars 130 have a gradient refractive
index gradually decreased along a direction from the part near the
encapsulation layer 120 to the part departing from the
encapsulation layer 120.
[0022] As indicated in FIG. 1A, in an embodiment, the light
emitting diode device 100 further comprises a plurality of
fluorescent particles 150 distributed within the encapsulation
layer 120.
[0023] As indicated in FIG. 1A, in an embodiment, the pillars 130
are regularly disposed on the encapsulation layer 120 and are
spaced apart from one another. In another embodiment, the pillars
130 may be irregularly (not illustrated) disposed on the
encapsulation layer 120 and are spaced apart from one another. In
an embodiment, the pillars 130 are such as circular pillars,
elliptical pillars, or polygonal pillars. As the pillars 130 are
disposed on the encapsulation layer 120 and are spaced apart from
one another, the light L may be emitted to the outside from the
side wall of the pillars 130 without being blocked by the side wall
of neighboring pillars 130 and reflected back to the encapsulation
layer 120 or the pillars 130. Since the light L may be effectively
emitted towards a light emitting direction, the light emitting
efficiency of the light emitting diode device 100 is thus
increased.
[0024] As shown in FIG. 1A, in an embodiment, a width D of the
pillars 130 is such as between 1 and 500 .mu.m, and a height H of
the pillars 130 is such as between 10 and 500 .mu.m. However, the
width, the height, the shape, and the interval of the pillars 130
may be properly selected according to actual needs in practical
applications. For example, the width, the height, the shape, and
the interval of the pillars 130 may be adjusted according to the
condition of the emitted light or may be optimized by using optical
simulation software, and are not limited to the above terms and
exemplifications.
[0025] FIG. 2 shows a partial diagram of the light emitting diode
device of FIG. 1A. As shown in FIG. 2, a partial surface 120b on
the encapsulation layer 120 is located between the pillars 130 with
no pillar disposed on the partial surface 120b. The partial surface
120b will be a direct interface between the encapsulation layer 120
and the air. When the light L emitted by the light emitting diode
element proceeds to the partial surface 120b in the encapsulation
layer 120, the light L reaching the partial surface 120b will be
total internal reflected and become a total internal reflection
light L2 reflected back to the encapsulation layer 120 if an angle
.theta. between the light L and the partial surface 120b is larger
than the critical angle.
[0026] FIGS. 3A-3B show partial diagrams of the pillars of a light
emitting diode device according to an embodiment of the invention.
Referring to FIG. 3A, the cross-sectional areas of the pillars 130
are gradually decreased or increased along a direction from the
part near the encapsulation layer 120 to the part departing from
the encapsulation layer 120. As shown in FIG. 3A, the pillars 130
have a cross-section parallel to the surface 120a of the
encapsulation layer 120, such as the cross-section formed along a
cross-sectional line A-A' and the cross-section formed along a
cross-sectional line B-B'. The area of the cross-section formed
along a cross-sectional line A-A' is larger than and the area of
the cross-section formed along a cross-sectional line B-B'.
Referring to FIG. 3B, the cross-sectional areas of the pillars 130
are gradually increased along a direction from the part near the
encapsulation layer 120 to the part departing from the
encapsulation layer 120. As shown in FIG. 3B, the area of the
cross-section formed along a cross-sectional line A-A' is smaller
than the area of the cross-section formed along a cross-sectional
line B-B'. When the cross-sectional areas of the pillars 130 are
gradually decreased along a direction from the part near the
encapsulation layer 120 to the part departing from the
encapsulation layer 120, the tilt angle of the side wall of the
pillars 130 enables the light L to be emitted to the outside via
the side wall of the pillars 130 without being total internal
reflected. Consequently, superior light emitting efficiency can
thus be achieved.
[0027] FIG. 4 shows a schematic diagram of a light emitting diode
device according to another embodiment of the invention. The
elements in this and previous embodiments sharing the same labeling
are the same elements, and the description of which are as
aforementioned.
[0028] As shown in FIG. 4, the light emitting diode device 200
comprises a light emitting diode element 110, an encapsulation
layer 120, a plurality of pillars 130, and a wrapping material 240.
The wrapping material 240 surrounds each of the pillars 130.
[0029] In an embodiment, the encapsulation layer 120 has a first
refractive index, the pillars 130 have a second refractive index,
and the wrapping material 240 has a third refractive index. The
first refractive index is larger than or equal to the third
refractive index. The third refractive index is smaller than or
larger than the second refractive index, in other words, the third
refractive index is not equal to the second refractive index. In
another embodiment, the wrapping material 240 has a gradient
refractive index gradually decreased along a direction from the
part near the encapsulation layer 120 to the part departing from
the encapsulation layer 120.
[0030] In an embodiment, the manufacturing method of the light
emitting diode device 200 is exemplified below. Firstly, a wrapping
material layer is formed on a surface of the encapsulation layer
120, and a plurality of holes is formed on the wrapping material
layer. Then, a pillar material is filled into the holes to form the
wrapping material 240 and the plurality of pillars 130 separately.
Under such circumstance, the wrapping material 240 and the
encapsulation layer 120 may be formed by the same or different
materials, but the material of the wrapping material 240 is
different from the material of the pillars 130.
[0031] In another embodiment, the manufacturing method of the light
emitting diode device 200 is exemplified below. Firstly, a
plurality of holes is formed on the surface of the encapsulation
layer 120. Then, a pillar material is filled into the holes to form
the wrapping material 240 and the plurality of pillars 130. Under
such circumstance, the wrapping material 240 is formed by a part of
the encapsulation layer 120, so the encapsulation layer 120 and the
wrapping material 240 are formed by the same material, but the
material of the pillars 130 is different from that of the wrapping
material 240 and the encapsulation layer 120.
[0032] FIG. 5 shows a schematic diagram of a light emitting diode
device according to an alternate embodiment of the invention. The
elements in this and previous embodiments sharing the same labeling
are the same elements, and the description of which are as
aforementioned.
[0033] As shown in FIG. 5, the light emitting diode device 300
comprises a light emitting diode element 110, an encapsulation
layer 120, a plurality of pillars 130, and a plurality of
fluorescent particles 351. The fluorescent particles 351 are
disposed between the encapsulation layer 120 and the pillars 130.
In an embodiment, the light emitting diode device 300 comprises,
for example, a phosphor layer 350 disposed between the
encapsulation layer 120 and the pillars 130, wherein the
fluorescent particles 351 are distributed within the phosphor layer
350. In an embodiment, the light emitting diode device 300 is such
as a remote phosphor light emitting diode display.
[0034] According to the light emitting diode device disclosed in
above embodiments of the invention, a plurality of pillars are
disposed on the encapsulation layer, so that less amount of the
lights emitted from light emitting diode element is total internal
reflected in the encapsulation layer, and the light emitting
efficiency of the light emitting diode device is thus increased.
Moreover, the pillars are disposed on the encapsulation layer and
are spaced apart from one another, such that the light will not be
blocked by the side wall of neighboring pillars and will thus be
effectively emitted towards the light emitting direction, hence
increasing the light emitting efficiency of the light emitting
diode device. Besides, when the cross-sectional areas of the pillar
are gradually decreased or increased along a direction from the
part near the encapsulation layer to the part departing from the
encapsulation layer, the tilt angle on the side wall of the pillars
enables the light to be emitted to the outside via the side wall of
the pillars 130 without being total internal reflected.
Consequently, superior light emitting efficiency can thus be
achieved.
[0035] While the invention has been described by way of example and
in terms of the preferred embodiment(s), it is to be understood
that the invention is not limited thereto. On the contrary, it is
intended to cover various modifications and similar arrangements
and procedures, and the scope of the appended claims therefore
should be accorded the broadest interpretation so as to encompass
all such modifications and similar arrangements and procedures.
* * * * *