U.S. patent application number 15/425630 was filed with the patent office on 2017-05-25 for light emitting apparatus.
The applicant listed for this patent is Seoul Semiconductor Co., Ltd.. Invention is credited to Hyuck Jung CHOI.
Application Number | 20170148772 15/425630 |
Document ID | / |
Family ID | 46926047 |
Filed Date | 2017-05-25 |
United States Patent
Application |
20170148772 |
Kind Code |
A1 |
CHOI; Hyuck Jung |
May 25, 2017 |
LIGHT EMITTING APPARATUS
Abstract
A light emitting apparatus is disclosed. The light emitting
apparatus includes a light-transmissive substrate having a top
surface and a bottom surface, at least one semiconductor light
emitting device disposed on the top surface of the
light-transmissive substrate, a reflective part disposed over the
semiconductor light emitting device to reflect light from the
semiconductor light emitting device toward the light-transmissive
substrate, and a first wavelength converter disposed between the
light-transmissive substrate and the reflective part.
Inventors: |
CHOI; Hyuck Jung; (Ansan-si,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Seoul Semiconductor Co., Ltd. |
Ansan-si |
|
KR |
|
|
Family ID: |
46926047 |
Appl. No.: |
15/425630 |
Filed: |
February 6, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13434510 |
Mar 29, 2012 |
|
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15425630 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F21V 23/06 20130101;
H01L 25/0753 20130101; H01L 27/156 20130101; H01L 2224/49107
20130101; H01L 33/504 20130101; H01L 2224/48091 20130101; H01L
2924/1815 20130101; H01L 33/508 20130101; H01L 2224/48091 20130101;
H01L 2224/48137 20130101; H01L 2224/48091 20130101; H01L 2924/00
20130101; H01R 33/05 20130101; H01L 33/22 20130101; F21Y 2115/10
20160801; H01L 33/62 20130101; H01L 33/60 20130101; H01L 33/54
20130101; H01L 33/507 20130101; H01L 2224/73265 20130101; H01L
33/505 20130101; H01L 2924/00014 20130101 |
International
Class: |
H01L 25/075 20060101
H01L025/075; F21V 23/06 20060101 F21V023/06; H01L 33/54 20060101
H01L033/54; H01L 33/60 20060101 H01L033/60; H01L 33/22 20060101
H01L033/22; H01L 33/50 20060101 H01L033/50 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2011 |
KR |
10-2011-0029093 |
Claims
1. A light emitting apparatus, comprising: a light-transmissive
substrate comprising a top surface and a bottom surface; a
semiconductor light emitting device disposed on the top surface of
the light-transmissive substrate; an optical member disposed over
the semiconductor light emitting device; a first wavelength
conversion part provided for converting a wavelength of light
emitted in a first direction, such that the first wavelength
conversion part converts a wavelength of light emitted from the
semiconductor light emitting device and directed to the optical
member; a second wavelength conversion part disposed on the bottom
surface of the light-transmissive substrate and provide for
converting a wavelength of light emitting in a second direction,
such that the second wavelength conversion part converts a
wavelength of light emitted from the semiconductor light emitting
device and directed to the light-transmissive substrate; and an
encapsulation part configured to encapsulate the semiconductor
light emitting device, wherein both of the first wavelength
conversion part and the encapsulation part are disposed between the
light-transmissive substrate and the optical member and comprise a
curved surface.
2. The light emitting apparatus according to claim 1, wherein the
optical member is a reflector.
3. The light emitting apparatus according to claim 2, wherein the
first wavelength conversion part is disposed on the reflector, such
that the reflector reflects light, which passes through the first
wavelength conversion part, toward the light-transmissive
substrate.
4. The light emitting apparatus according to claim 3, wherein the
second wavelength conversion part is disposed at a position
corresponding to the semiconductor device on the bottom surface of
the light-transmissive substrate.
5. The light emitting apparatus according to claim 3, wherein the
encapsulation part is formed in a lens shape, wherein the light
emitted from the semiconductor light emitting device is condensed
into the reflector.
6. The light emitting apparatus according to claim 1, wherein the
first wavelength conversion part is disposed on the encapsulation
part.
7. The light emitting apparatus according to claim 1, wherein a
space between the optical member and the encapsulation part is
empty.
8. The light emitting apparatus according to claim 1, wherein a
space between the first wavelength conversion part and the
light-transmissive substrate is filled with the encapsulation
part.
9. The light emitting apparatus according to claim 8, wherein the
encapsulation part is made of a light transmissive material
selected from a group of an epoxy, a silicon resin and their
combination.
10. The light emitting apparatus according to claim 1, further
comprising a light spreading part positioned on the bottom surface
of the light-transmissive substrate.
11. The light emitting apparatus according to claim 1, further
comprising at least one electrode provided on the top surface of
the light-transmissive substrate and connected to the semiconductor
light emitting device by using a bonding wire.
12. The light emitting apparatus according to claim 1, further
comprising an adhesive material configured to adhere the
semiconductor light emitting device to the light-transmissive
substrate.
13. The light emitting apparatus according to claim 1, further
comprising an anti-retroreflection layer interposed between the
second wavelength conversion part and the bottom surface of the
light-transmissive substrate.
14. The light emitting apparatus according to claim 1, further
comprising a concavo-convex pattern for improving light extraction
formed on the bottom surface of the light-transmissive
substrate.
15. A light emitting apparatus, comprising: a light-transmissive
substrate comprising a top surface and a bottom surface; a
plurality of semiconductor light emitting devices disposed on the
top surface of the light-transmissive substrate; a first wavelength
converter provided for converting a wavelength of light emitted
from the plurality of semiconductor light emitting devices to the
first wavelength converter; a second wavelength converter disposed
on the bottom surface of the light-transmissive substrate, that the
second wavelength converter converting a wavelength of light
emitted from the plurality of semiconductor light emitting devices
and directed to the light-transmissive substrate; and an
encapsulation part configured to encapsulate the plurality of
semiconductor light emitting devices and disposed between the
light-transmissive substrate and the first wavelength converter,
wherein the plurality of semiconductor light emitting devices are
connected in series to form an array of semiconductor light
emitting devices; and wherein the light-transmissive substrate
comprises a pair of electrodes disposed on the top surface thereof
and each of the electrodes is provided at opposite ends of the
array of semiconductor light emitting devices.
16. The light emitting apparatus according to claim 15, further
comprising an optical member disposed over the encapsulation
part.
17. The light emitting apparatus according to claim 16, wherein the
optical member is configured to change a path of light emitted from
the plurality of semiconductor light emitting devices and passing
through the first wavelength converter.
18. The light emitting apparatus according to claim 17, wherein the
optical member is a reflector to reflect light emitted from the
plurality of semiconductor light emitting devices toward the
light-transmissive substrate.
19. The light emitting apparatus according to claim 18, wherein the
encapsulation part has a surface curved with respective to the
plurality of semiconductor light emitting devices.
20. The light emitting apparatus according to claim 16, wherein a
space between the optical member and the encapsulation part is
empty.
21. The light emitting apparatus according to claim 15, wherein the
encapsulation part is made of a light transmissive material
selected from a group of an epoxy, a silicon resin and their
combination, with which a space between the first wavelength
converter and the light-transmissive substrate is entirely
filled.
22. The light emitting apparatus according to claim 15, wherein
each of the plurality of semiconductor light emitting devices is
electrically connected by using a bonding wire.
23. The light emitting apparatus according to claim 15, further
comprising an adhesive material configured to adhere the plurality
of semiconductor light emitting devices to the top surface of the
light-transmissive substrate.
24. An illumination device, comprising: a light emitting apparatus
according to claim 15; and a socket configured for detachably
mounting the illumination device to a structure disposed indoors or
outdoors, wherein the socket is configured to electrically connect
the pair of electrodes of the light emitting apparatus to a power
supply terminal of the structure.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a Continuation of U.S. patent
application Ser. No. 13/434,510, filed on Mar. 29, 2012, which
claims priority from and the benefit of Koran Patent Application
No. 10-2011-0029093, filed on Mar. 30, 2011, each of which is
hereby incorporated by reference for all purposes as if fully set
forth herein.
BACKGROUND OF THE INVENTION
[0002] Field of the Invention
[0003] Exemplary embodiments of the present invention relate to a
light emitting apparatus. More particularly, exemplary embodiments
of the present invention relate to a light emitting apparatus that
uses a semiconductor light emitting device such as a light emitting
diode as a light source.
[0004] Discussion of the Background
[0005] For a long period of time, cold cathode fluorescent lamps,
referred to as "fluorescent lamps," have been widely used as indoor
or outdoor illumination devices in buildings. However, the cold
cathode fluorescent lamps have disadvantages such as a short
lifespan, poor durability, a limited range of color selection of
light and low energy efficiency.
[0006] Although light emitting diodes (LEDs) have several
advantages such as an excellent responsiveness, high energy
efficiency and long lifespan, the usage of light emitting diodes
has been confined to limited areas such as backlight sources of a
small-sized display device, and the like. However, as
high-luminance, high-power white LEDs have been developed, LEDs
have recently drawn attention as light sources of light
illumination apparatuses.
[0007] A typical light emitting apparatus for illumination includes
a semiconductor light emitting device such as a light emitting
diode, and a substrate such as a printed circuit board. The
semiconductor light emitting device may be directly mounted on the
printed circuit board, or a package having the semiconductor light
emitting device built therein may be mounted on a printed circuit
board. When the semiconductor light emitting device is mounted on
the substrate or package, a large amount of light is lost in a
boundary between the semiconductor light emitting device and the
substrate or package. Particularly, in case of a light emitting
diode chip using a light-transmissive substrate such as a sapphire
substrate as a semiconductor growth substrate or a support
substrate, a large amount of light can be used through the
light-transmissive substrate. However, the light may be blocked by
the printed circuit board or package and the light intensity may be
reduced.
SUMMARY OF THE INVENTION
[0008] Therefore, reducing light loss on a surface attached to an
object such as a substrate, i.e., a chip mounting surface may be
desirable.
[0009] If light that exits a chip mounting surface of a
semiconductor light emitting device is used, the range of light
emitted from the semiconductor light emitting device is
considerably widened. In this case, a technique for concentrating
light emitted within a wide range into a desired region or space is
required.
[0010] Furthermore, a new phosphor arrangement technique is
required in order to obtain light of a desired color, e.g., white
light, by converting the wavelength of light emitted within a wide
range as described above.
[0011] According to an aspect of the present invention, there is
provided a light emitting apparatus including: a light-transmissive
substrate having a top surface and a bottom surface, at least one
semiconductor light emitting device disposed on the top surface of
the light-transmissive substrate, a reflective part disposed over
the semiconductor light emitting device to reflect light from the
semiconductor light emitting device toward the light-transmissive
substrate, and a first wavelength converter disposed between the
light-transmissive substrate and the reflective part.
[0012] According to another aspect of the present invention, there
is provided a light emitting apparatus including: a
light-transmissive substrate having a top surface and a bottom
surface, a plurality of semiconductor light emitting devices
arranged on the top surface of the light-transmissive substrate, a
reflector to reflect light emitted from the plurality of
semiconductor light emitting devices toward the light-transmissive
substrate, a first wavelength converter to convert a wavelength of
the light reflected by the reflector, and a second wavelength
converter to convert a wavelength of the light exiting from a
bottom surface of the semiconductor light emitting device.
[0013] According to still another aspect of the present invention,
there is provided a light emitting apparatus including: a
light-transmissive substrate having a top surface and a bottom
surface, a semiconductor light emitting device disposed on the top
surface of the light-transmissive substrate, a reflective part
disposed over the semiconductor light emitting device to reflect
light from the semiconductor light emitting device toward the
light-transmissive substrate, and a wavelength converter disposed
on the light-transmissive substrate to convert a wavelength of the
light emitted through the light-transmissive substrate.
[0014] The terms indicating orientations or directions, i.e., "top
surface," "bottom surface," "upper side," "upper portion," "lower
portion," and the like, which are used in the specification and
claims, merely indicate relative position relations or orientations
as shown in the accompanying drawings. For example, an element
described as a "top surface" may substantially become a "bottom
surface." On the contrary, an element described as a "bottom
surface" may substantially become a "top surface."
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate exemplary
embodiments of the invention, and together with the description
serve to explain the principles of the invention.
[0016] FIG. 1 is a cross-sectional view showing a light emitting
apparatus according to an exemplary embodiment.
[0017] FIG. 2 is a cross-sectional view taken along line I-I of
FIG. 1, showing the light emitting apparatus according to the
exemplary embodiment.
[0018] FIG. 3, FIG. 4, FIG. 5, FIG. 6, FIG. 7, FIG. 8, and FIG. 9
are cross-sectional views illustrating various other exemplary
embodiments.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0019] The present invention will be described more fully
hereinafter with reference to the accompanying drawings, in which
exemplary embodiments of the invention are shown. This invention
may, however, be embodied in many different forms and should not be
construed as limited to the exemplary embodiments set forth herein.
Rather, these exemplary embodiments are provided so that this
disclosure is thorough, and will fully convey the scope of the
invention to those skilled in the art.
[0020] In the drawings, the thickness of layers, films, panels,
regions, etc., may be exaggerated for clarity. It will be
understood that when an element or layer is referred to as being
"on" or "connected to" another element or layer, it can be directly
on or directly connected to the other element or layer, or
intervening elements or layers may be present. In contrast, when an
element is referred to as being "directly on" or "directly
connected to" another element or layer, there are no intervening
elements or layers present. In contrast, It will be understood that
when an element such as a layer, film, region, or substrate is
referred to as being "beneath" another element, it can be directly
beneath the other element or intervening elements may also be
present. Meanwhile, when an element is referred to as being
"directly beneath" another element, there are no intervening
elements present. It will be understood that for the purposes of
this disclosure, "at least one of X, Y, and Z" can be construed as
X only, Y only, Z only, or any combination of two or more items X,
Y, and Z (e.g., XYZ, XYY, YZ, ZZ).
[0021] Hereinafter, exemplary embodiments of the present invention
will be explained in detail with reference to the accompanying
drawings.
[0022] FIG. 1 is a cross-sectional view showing a light emitting
apparatus according to an exemplary embodiment of the present
invention; and FIG. 2 is a cross-sectional view taken along line
I-I of FIG. 1, showing the light emitting apparatus according to an
exemplary embodiment of the present invention.
[0023] Referring to FIG. 1 and FIG. 2, a light emitting apparatus 1
according to an exemplary embodiment of the present invention may
include a light-transmissive substrate 10 which may be made of
light-transmissive material, such as a glass material,
semiconductor light emitting devices 20, a reflector 30, and first
and second wavelength converters 40 and 50.
[0024] The light-transmissive substrate 10 includes a top surface
10a having the semiconductor light emitting device 20 disposed
thereon, and a bottom surface 10b opposite to the top surface 10a.
Electrode patterns 11a and 11b are formed on the top surface 10a of
the light-transmissive substrate 10 so that power can be applied to
the semiconductor light emitting device 20. The electrode patterns
11a and 11b may be formed of a material having conductivity and
transmissivity, such as indium tin oxide (ITO). The electrode
patterns 11a and 11b may be formed using a printing technique or
the like. The light-transmissive substrate 10 may be not only a
glass substrate but also a substrate of various materials having
light transmissivity, e.g., a resin substrate, a quartz substrate,
a ceramic substrate, and the like.
[0025] The semiconductor light emitting device 20 is disposed on
the top surface 10a of the light-transmissive substrate 10. In this
exemplary embodiment, the semiconductor light emitting device 20
includes p-type and n-type semiconductor layers, and may be a light
emitting diode (LED) chip, which emits light from a light emitting
region (or active region) between the p-type and n-type
semiconductor layers. The semiconductor light emitting device 20 is
attached to the top surface 10a of the light-transmissive substrate
10 by an adhesive material 21 having light transmissivity. The
semiconductor light emitting device 20 allows light to be emitted
not only from top and side surfaces but also from a bottom surface
thereof. For example, an LED chip including a light-transmissive
substrate, such as a sapphire substrate, as a semiconductor growth
substrate or semiconductor support substrate, allows light to be
emitted not only from top and side surfaces but also from a bottom
surface thereof. Light emitted from the bottom surface of the
semiconductor light emitting device 20 is directed downward through
the light-transmissive adhesive material 21 and the
light-transmissive substrate 10. It is also possible to form a
reflective insulation layer to cover the side surfaces of the
semiconductor light emitting device.
[0026] Here, the desired direction of illumination of the light
emitting apparatus 1, the illumination direction, is downward from
the bottom surface of the light-transmissive substrate 10, i.e., a
direction opposite to the direction in which the semiconductor
light emitting device 20 is mounted.
[0027] In this exemplary embodiment, a plurality of semiconductor
light emitting devices 20 may be arranged on the top surface 10a of
the light-transmissive substrate 10. The semiconductor light
emitting devices 20 may be arranged as a matrix array on the
light-transmissive substrate 10. As shown in the drawings, the
plurality of semiconductor light emitting devices may be arranged
in two rows. Two electrode patterns 11a and 11b are provided for a
semiconductor light emitting device 20. Electrodes of each
semiconductor light emitting device 20 are connected to the
electrode patterns 11a and 11b through bonding wires W,
respectively.
[0028] The reflector 30 is disposed over the light-transmissive
substrate 10 so as to be spaced apart from the top surface 10a of
the light-transmissive substrate 10. The semiconductor light
emitting device 20 is disposed between the reflector 30 and the
light-transmissive substrate 10. The reflector 30 and the
semiconductor light emitting device 20 are spaced apart from each
other. According to an exemplary embodiment, the space therebetween
may be empty. The reflector 30 includes a plurality of reflective
parts 32, which are provided at positions corresponding to the
plurality of semiconductor light emitting devices 20. The
reflective part 32 may be made of metallic material or high
reflective resin material. Further, the reflective part 32 may be
formed by depositing metallic material on a resin surface.
[0029] In this exemplary embodiment, each of the plurality of
reflective parts 32 includes a reflective surface having a concave
shape, and serves to reflect light emitted from the corresponding
semiconductor light emitting device 20 to the light-transmissive
substrate 10. The efficiency of light emission of the light
emitting apparatus 1 may vary depending on the shape and size of
the reflective part 32, and the reflective part 32 should be
designed to have an appropriate size and shape, considering the
desired angle of emission of the semiconductor light emitting
device 20, an interval between the semiconductor light emitting
devices 20, and the like. The reflector 30 may be designed so that
only the reflective part 32 reflects light. Alternatively, the
reflector 30 may be designed so that the entire surface of the
reflector 30 reflects light.
[0030] The first wavelength converter 40 is disposed in a light
path between the light-transmissive substrate 10 and the reflector
30, which allows the wavelength-converted light by the first
wavelength converter 40 to be widely reflected by the reflector 30
and then to proceed externally, thereby contributing to reducing
the disposal area of the first wavelength converter 40 and further
reducing the amount of phosphor. Furthermore, as shown in the
drawing, the first wavelength converters 40 may be disposed on the
reflective parts 32 of the reflector 30, into which light beams are
concentrated, so that the wavelength conversion efficiency can be
improved to a higher degree with a small amount of phosphor.
[0031] In addition to the first wavelength converters 40, the light
emitting apparatus 1 is also equipped with the second wavelength
converters 50. The second wavelength converters 50 are disposed on
the light-transmissive substrate 10. In this exemplary embodiment,
the second wavelength converter 50 is disposed on the bottom
surface of the light-transmissive substrate 10 so as to convert the
wavelength of the light emitted from the bottom surface of the
semiconductor light emitting device 20. The second wavelength
converter 50 is disposed right below under one of the plurality of
semiconductor light emitting devices 20, and may be formed to have
an area slightly wider than that of the bottom surface of the
semiconductor light emitting device 20, considering that the light
emitted from the bottom surface of the semiconductor light emitting
device 20 is spread more widely while passing through the
light-transmissive substrate 10. The second wavelength converters
50 may be formed by coating a phosphor on the corresponding regions
at the bottom surface 10b of the light-transmissive substrate
10.
[0032] The first wavelength converter 40 performs conversion of the
wavelength of the light reflected by the reflector 30, and the
second wavelength converter 50 performs conversion of the
wavelength of the light not reflected by the reflector 30. Thus, it
is possible to substantially uniformly convert the wavelength of
the light emitted from the semiconductor light emitting device 20
and emit the wavelength-converted light externally. The wavelength
converter 40 or 50 may include garnet, silicate and/or Nitride
phosphor, but not limited thereto.
[0033] The light emitting apparatus 1 according to this exemplary
embodiment may be implemented by appropriately disposing the
light-transmissive substrate 10 equipped with the semiconductor
light emitting device 20 and the like for a structure including the
reflector 30 and the first wavelength converters 40. For example,
in case the reflector 30 and its related components are secured for
use indoors or outdoors, the light emitting apparatus 1 may be
implemented by mounting the structure with the light-transmissive
substrate 10 equipped with the semiconductor light emitting device
20 and the like in a replaceable manner. In this case, the
structure may be provided with a power supply terminal, and the
light-transmissive substrate 10 or any other structure including
the same may be provided with a terminal or socket through which
the electrode patterns 11a and 11b on the light-transmissive
substrate 10 are electrically connected to the power supply
terminal. However, the light-transmissive substrate 10 of a glass
material, the semiconductor light emitting device 20, the reflector
30, the first and second wavelength converters 40 and 50, and the
like may be integrated in advance, and then, the light emitting
apparatus 1 may be installed to any structure including a power
source and/or a power supply terminal.
[0034] Hereinafter, various other exemplary embodiments of the
present invention will be described. In the descriptions of the
following exemplary embodiments, the descriptions overlapping with
the aforementioned exemplary embodiment will be omitted, and the
components identical or similar to those of the aforementioned
exemplary embodiment may use the reference numerals used to
describe the aforementioned exemplary embodiment.
[0035] FIG. 3 is a cross-sectional view showing a light emitting
apparatus according to another exemplary embodiment of the present
invention.
[0036] Referring to FIG. 3, a light emitting apparatus 1 according
to this exemplary embodiment further includes a light spreading
part 16 disposed as a layer on the bottom surface 10b of the
light-transmissive substrate 10. The light spreading part 16 is
stacked on the bottom surface 10b of the light-transmissive
substrate 10, and serves to increase the angle of direction of
light emission externally through the light-transmissive substrate
10. In this exemplary embodiment, the light spreading part 16 may
include a concave groove in order to accommodate the second
wavelength converter 50. The light spreading part 16 may be
provided in a variety of manners, including attaching a spreading
film to the bottom surface 10b of the light-transmissive substrate
10, coating a spreading material to the bottom surface 10b of the
light-transmissive substrate 10, and the like.
[0037] FIG. 4 is a cross-sectional view showing a light emitting
apparatus according to still another exemplary embodiment of the
present invention.
[0038] Referring to FIG. 4, an anti-retroreflection layer 17 is
disposed on the bottom surface 10b of the light-transmissive
substrate 10. The anti-retroreflection layer 17 is interposed
between the light spreading part 16 and second wavelength converter
50 and the light-transmissive substrate 10 thereabove. The
anti-retroreflection layer 17 reduces the light emitting through
the light-transmissive substrate 10 reflected by the phosphor of
the second wavelength converter 50 or other components and then
retroreflected to the light-transmissive substrate 10. The
anti-retroreflection layer 17 may be disposed throughout the entire
region on the bottom surface 10b of the light-transmissive
substrate 10. Alternatively, the anti-retroreflection layer 17 may
be disposed only at a region corresponding to the semiconductor
light emitting device 20. Also, the anti-retroreflection layer 17
may be disposed as a distributed Bragg reflector (DBR) to reflect
the light with a specific wavelength band of the
anti-retroreflection layer 17. In this case, the light
retroreflected by colliding with the phosphor of the second
wavelength converter 50 is reflected by the anti-retroreflection
layer 17 with a DBR structure, and therefore, is not retroreflected
into the light emitting apparatus 1. An anti-retroreflection layer
identical or similar to that described above may also be disposed
between the top surface of the light-transmissive substrate 10 and
the electrode pattern.
[0039] FIG. 5 is a cross-sectional view showing a light emitting
apparatus according to still another exemplary embodiment of the
present invention.
[0040] Referring to FIG. 5, a light emitting apparatus 1 according
to this exemplary embodiment further includes light-transmissive
encapsulants 18, each of which is formed on the top surface 10a of
the light-transmissive substrate 10 to individually encapsulate the
corresponding semiconductor light emitting device 20 and bonding
wires W. The encapsulant 18 may be formed of, for example, epoxy or
silicon resin. The encapsulant 18 may have a shape of a lens to
enable the light emitted from the semiconductor light emitting
device 20 to be concentrated into the corresponding reflective part
32.
[0041] FIG. 6 is a cross-sectional view showing a light emitting
apparatus according to still another exemplary embodiment of the
present invention.
[0042] Referring to FIG. 6, a light emitting apparatus 1 according
to this exemplary embodiment includes a light-transmissive
encapsulant 18' to encapsulate the semiconductor light emitting
device 20 and the bonding wires W, similar to the previous
exemplary embodiment, but the space between the light-transmissive
substrate 10 and the reflector 30 is filled with the
light-transmissive encapsulant 18'. The light-transmissive
encapsulant 18' preferably has a refractive index close to that of
the light-transmissive substrate 10.
[0043] FIG. 7 is a cross-sectional view showing a light emitting
apparatus according to still another exemplary embodiment of the
present invention.
[0044] Referring to FIG. 7, a light emitting apparatus 1 according
to this exemplary embodiment is provided with two or more electrode
patterns 11a and 11b having different polarities for one
semiconductor light emitting device 20, and the semiconductor light
emitting device 20 is directly mounted to one of the electrode
patterns 11a and 11b. This may be suitable when a vertical LED chip
or the like, in which at least one of opposite electrodes exists
under the semiconductor light emitting device, is used as the
semiconductor light emitting device. In this case, at least a
portion of a lower electrode structure of the semiconductor light
emitting device 20 preferably has light transmissivity. In the
structure shown in FIG. 7, it is advantageous that an
anti-retroreflection layer is formed between the top surface of the
light-transmissive substrate 10 and the electrode pattern.
[0045] FIG. 8 is a cross-sectional view showing a light emitting
apparatus according to still another exemplary embodiment of the
present invention.
[0046] Referring to FIG. 8, in a light emitting apparatus 1
according to this exemplary embodiment, a plurality of
semiconductor light emitting devices 20 on the top surface 10a of
the light-transmissive substrate 10 are connected in series,
thereby forming one serial array. Unlike the previous exemplary
embodiment in which the electrode patterns 11a and 11b are provided
for each of the semiconductor light emitting devices 20, the
electrode patterns 11a and 11b are respectively provided only at
both ends of the array.
[0047] FIG. 9 is a cross-sectional view showing a light emitting
apparatus according to still another exemplary embodiment of the
present invention.
[0048] Referring to FIG. 9, in a light emitting apparatus 1
according to this exemplary embodiment, the light-transmissive
substrate 10 includes top and bottom surfaces 10a and 10b, and the
bottom surface 10b defining a boundary with a medium such as outer
air is formed with patterns 101 to improve light emission. The
patterns 101 may be regular or, alternatively, irregular. The
patterns 101 may be formed through roughening, texturing, etching,
or the like. Furthermore, if the light-transmissive substrate 10 is
formed using a method such as molding, the patterns 101 may be
formed in a formation process.
[0049] Although not shown in the drawings, the bottom surface of
the reflector 30 (See FIG. 1 to FIG. 8) and the top surface of the
substrate 10 (See FIG. 1 to FIG. 8) may alternatively be in contact
with each other. In this case, a semiconductor light emitting
device, a conductive pattern, further an encapsulant and the like
may be disposed in a spaced between the concave reflector and the
substrate by allowing only a partial region of the reflector, e.g.,
a region of the concave reflector, in which the wavelength
converter is formed, to be spaced apart from the top surface of the
substrate.
[0050] According to the exemplary embodiments of the present
invention, the availability of light emitted through the bottom
surface of the semiconductor light emitting device can be
increased, thereby improving the efficiency of light emission.
Further, the light emitted through the top surface of the
semiconductor light emitting device and the light emitted through
the bottom surface of the semiconductor light emitting device can
be uniformly wavelength-converted, thereby being applied to
illumination and the like. Although layer 17 is shown in FIG. 4
only and layer 16 is shown in FIG. 3 and FIG. 4 only, each or both
of these layers may be included in any exemplary embodiments.
[0051] It will be apparent to those skilled in the art that various
modifications and variation can be made in the present invention
without departing from the spirit or scope of the invention. Thus,
it is intended that the present invention cover the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
* * * * *