U.S. patent application number 14/657714 was filed with the patent office on 2015-09-17 for light-emitting array.
The applicant listed for this patent is EPISTAR CORPORATION. Invention is credited to Chao-Hsing Chen, Guan-Ru He, Min-Hsun Hsieh, Chia-Liang Hsu, Jui-Hung Yeh.
Application Number | 20150263256 14/657714 |
Document ID | / |
Family ID | 54069900 |
Filed Date | 2015-09-17 |
United States Patent
Application |
20150263256 |
Kind Code |
A1 |
Hsieh; Min-Hsun ; et
al. |
September 17, 2015 |
LIGHT-EMITTING ARRAY
Abstract
The present application discloses a light-emitting array,
comprising a first light-emitting chip; a second light-emitting
chip; and a conductive line electrically connected to the first
light-emitting chip and the second light-emitting chip, wherein the
conductive line includes a first segment and a second segment
having a radius curvature different from that of the first
segment.
Inventors: |
Hsieh; Min-Hsun; (Hsinchu,
TW) ; He; Guan-Ru; (Hsinchu, TW) ; Chen;
Chao-Hsing; (Hsinchu, TW) ; Yeh; Jui-Hung;
(Hsinchu, TW) ; Hsu; Chia-Liang; (Hsinchu,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
EPISTAR CORPORATION |
Hsinchu |
|
TW |
|
|
Family ID: |
54069900 |
Appl. No.: |
14/657714 |
Filed: |
March 13, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61953236 |
Mar 14, 2014 |
|
|
|
61973394 |
Apr 1, 2014 |
|
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|
61973423 |
Apr 1, 2014 |
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Current U.S.
Class: |
257/91 |
Current CPC
Class: |
H01L 2924/3512 20130101;
H01L 2224/18 20130101; H01L 33/38 20130101; H01L 25/0753 20130101;
H01L 2224/19 20130101; H01L 2224/04105 20130101; H01L 21/568
20130101; H01L 33/62 20130101; H01L 33/36 20130101 |
International
Class: |
H01L 33/62 20060101
H01L033/62; H01L 27/15 20060101 H01L027/15 |
Claims
1. An light-emitting array, comprising: a first light-emitting
chip; a second light-emitting chip; and a conductive line
electrically connecting to the first light-emitting chip and the
second light-emitting chip, wherein the conductive line comprises a
first segment and a second segment having a radius curvature
different from that of the first portion.
2. The light-emitting array of claim 1, wherein the first
light-emitting chip comprises a first pad, two second pads, a
rectangular shape and four corners.
3. The light-emitting array of claim 2, wherein two of the corners
are located in a diagonal line, and the two second pads are formed
on the diagonal corners.
4. The light-emitting array of claim 3, wherein the first pad
extends between two of the corners and in a direction passing
through the diagonal line.
5. The light-emitting array of claim 1, wherein the conductive line
comprises a first portion connecting on the second light-emitting
chip and a second portion connecting the first portion, and the
first portion has a width more large than the second portion
has.
6. The light-emitting array of claim 1, wherein the conductive line
comprises a stretchable segments having a width W, and a first
vertex and a vertex arranged in a distance L, and a ratio between
the width W and the distance L is between 0.1.about.0.4.
7. The light-emitting array of claim 1, further comprising: a first
conductive line connecting to a first pad of the first
light-emitting chip; and a second conductive line connecting to a
second pad of the first light-emitting chip, wherein an area of the
first conductive line connecting to the first pad is larger than
that of the second conductive line connecting to the second
pad.
8. The light-emitting array of claim 1, wherein the conductive line
comprises a connection portion not directly connecting to the first
light-emitting chip, and a ratio between a width of the connection
portion and a width of the first light-emitting chip is between 2
to 10.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to and the benefit of a
U.S. Provisional Application Ser. No. 61/953,236 filed on Mar. 14,
2014, a U.S. Provisional Application Ser. No. 61/973,394 filed on
Apr. 1, 2014, and a U.S. Provisional Application Ser. No.
61/973,423 filed on Apr. 1, 2014, which is incorporated by
references in its entirety.
BACKGROUND
[0002] 1. Technical Field
[0003] The present application discloses a light-emitting array
comprising multiple semiconductor light-emitting stacks and
conductive wires connecting the semiconductor light-emitting
stacks.
[0004] 2. Description of the Related Art
[0005] Following incandescent light, traditional lighting devices
have been gradually substituted by solid-state lighting devices
consisted of the light-emitting diodes because the light-emitting
diodes (LEDs) have the characteristics of low power consumption,
environment friendly, long life span, and compact. Moreover, the
LED capable of emitting a white light has a strong need in the
market.
[0006] Thus, the LED is gradually adopted in several aspects of
applications. For example, some monitors are using LEDs as the
light-emitting units of a backlight module, and some cameras or
cellphones adopt LEDs as the flash lights. Furthermore, the LED not
only provides luminance for people to see the object; in some
products, the LEDs are applied to pixels of a display, that is the
LED is formed in an LED based monitor, such as an LED TV, or formed
in an outdoor billboard for the benefit of high reliability against
the sunlight, wind or rain.
SUMMARY OF THE DISCLOSURE
[0007] An light-emitting array, comprising a first light-emitting
chip; a second light-emitting chip; and a conductive line
electrically connecting to the first light-emitting chip and the
second light-emitting chip, wherein the conductive line comprises a
first segment and a second segment having a radius curvature
different from that of the first portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1A shows a top view of a light-emitting array in an
un-stretched state in accordance with an embodiment of the present
invention.
[0009] FIG. 1B shows a cross-sectional view along U-U' line in FIG.
1A.
[0010] FIG. 1C shows a cross-sectional view along V-V' line in FIG.
1A.
[0011] FIG. 1D shows a top view of the light-emitting array of FIG.
1A in a stretched state.
[0012] FIGS. 1E.about.1I show the process of manufacturing the
structures in FIGS. 1A.about.1D.
[0013] FIG. 2A shows a top view of a light-emitting array in an
un-stretched state in accordance with further embodiment of the
present invention.
[0014] FIG. 2B shows a top view of the light-emitting array of FIG.
2A in a stretched state.
[0015] FIGS. 2C-2D show cross-sectional views along V-V' line and
along U-U' line in FIG. 2A.
[0016] FIG. 3A shows a top view of a light-emitting array in an
un-stretched state in accordance with another embodiment of the
present invention.
[0017] FIG. 3B shows a top view of a light-emitting array in an
un-stretched state in accordance with an embodiment of the present
invention.
[0018] FIGS. 3C-3G show conductive line in accordance with
embodiments of the present application.
[0019] FIG. 4A shows a top view of a light-emitting array in an
un-stretched state in accordance with another embodiment of the
present invention.
[0020] FIG. 4B shows a top view of the light-emitting array in a
stretched state.
[0021] FIG. 4C shows cross-sectional views of an LED array shown in
FIG. 4A.
[0022] FIG. 4D shows a top view of a light-emitting array in an
un-stretched state in accordance with further embodiment of the
present invention.
[0023] FIG. 4E shows a cross-sectional view of a light-emitting
group in accordance with an embodiment of the present
invention.
[0024] FIG. 5A shows a top view in an un-stretched state in
accordance with a more embodiment of the present invention.
[0025] FIG. 5B shows a cross-sectional view along the line A-A' in
FIG. 5A.
[0026] FIG. 5C shows a cross-sectional view taken along the line
B-B' in FIG. 5A.
[0027] FIGS. 5D-5H show control element in accordance with an
embodiment of the present application.
[0028] FIG. 6A shows a top view of a light-emitting array in an
un-stretched state in accordance with an embodiment of the present
invention.
[0029] FIG. 6B shows a top view of a light-emitting array in an
un-stretched state in accordance with an embodiment of the present
invention.
[0030] FIGS. 7A-7G show steps of making the light-emitting array of
FIG. 1A.
[0031] FIGS. 8A-8G show the manufacturing steps related to the
embodiment of the application.
[0032] FIGS. 9A-9E show a cross-sectional view and manufacturing
process in accordance with a further embodiment of the present
invention.
[0033] FIGS. 10A-10F show a structure of the light-emitting unit 30
in accordance with an embodiment of the present invention.
[0034] FIGS. 11A-11F show a structure of the light-emitting unit 30
in accordance with an embodiment of the present invention.
[0035] FIGS. 12A-12G show a structure of the light-emitting unit 30
in accordance with an embodiment of the present invention.
[0036] FIGS. 13A-13B show a structure of the light-emitting unit 30
in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0037] To better and concisely explain the disclosure, the same
name or the same reference number given or appeared in different
paragraphs or figures along the specification should has the same
or equivalent meanings while it is once defined anywhere in the
disclosure.
[0038] The following shows the description of the embodiments of
the present disclosure in accordance with the drawings.
[0039] FIG. 1A illustrates a top view of a light-emitting array in
an un-stretched state in accordance with an embodiment of the
present invention. The light-emitting array is a 2-dimension array
and includes a plurality of light-emitting chips 41. Each of the
light-emitting chips 41 has two first pads 301 (n-pad or p-pad) and
a second pad 302 (p-pad or n-pad). The light-emitting chips 41 are
electrically connected to each other by a plurality of extendable
or stretchable conductive line 23 (A1-An and B1-Bn). Specifically,
the second pads 302 of two adjacent light-emitting chips 41 are
electrically connected by the conductive line 23 (B1-Bn). One of
the first pads 301 of a light-emitting chips 41 is electrically
connected to the other of the first pad 301 of adjacent
light-emitting chip 41 by the conductive line 23 (A1-An).
Therefore, for example, when the conductive lines 23 (An-1 and B1)
are electrically connected to an external element (such as power
supply or IC), the light-emitting chip 41A can emit light; when the
conductive lines 23 (An and Bn) are electrically connected to the
external element (power supply or IC), the light-emitting chip 41C
can emit light. By selectively connecting the conductive line 23
with the external element, a specific light-emitting chip 41 can
emit light. The light-emitting array can be used as a backlight for
a display or formed to be an LED display. The light-emitting chips
41 are separated from each other on a substrate 11 by a distance
(D1) larger than 1 mil. In one embodiment, the conductive line 23
has two connecting segments 231, and a stretchable segment 232
electrically and physically connected to the two connecting
segments 231. The stretchable segment 232 further includes a
portion having a radius curvature different from that of the
connecting segment 231. To be more specific, the conductive line 23
connecting two adjacent light-emitting chips 41 arranged in an X
direction has two connecting segments 231 and one stretchable
segment 232. The stretchable segment 232 has a length (L1) and a
curved or straight shape. The conductive line 23 connecting two
adjacent light-emitting chips 41 arranged in a Y direction has two
connecting segments 231 and one stretchable segment 232. The
stretchable segment 232 has a length (L2) and a curved or straight
shape. Moreover, it can have none, one or more connecting segments
231 formed on each light-emitting chip 41. If no connecting segment
is formed, the stretchable segment 232 is directly connected to the
light-emitting chip 41. If two or more connecting segments 231 are
formed, each connecting segment 231 can be connected to at least
one stretchable segment 232 in an X direction or in a Y
direction.
[0040] In another embodiment, the width of the connecting segment
231 is larger than the width of the stretchable segment 232.
However, various modifications and variations can be made to the
conductive line 23 in accordance with the present disclosure
without departing from the scope or spirit of the disclosure.
[0041] FIG. 1B shows a cross-sectional view along U-U' line in FIG.
1A. Each of the light-emitting chips 41 has a light-emitting stack,
which includes a first-type semiconductor layer 311, an active
layer 312, and a second-type semiconductor layer 313, which are
epitaxially grown on the substrate 11 (sapphire, SiC, GaN or GaAs).
The structure of the active layer 312 can be single heterostructure
(SH), double heterostructure (DH), double-side double
heterostructure (DDH) or multi-quantum well (MQW) structure. Each
of the light-emitting chips 41 has two first pads 301 formed on the
first-type semiconductor layer 311 and a second pad 302 formed on
the second-type semiconductor layer 313. For example, the first pad
301 is an n-pad (or p-pad) and the second pad 302 is a p-pad (or
n-pad). A plurality of first trenches 111 is formed on the
substrate 11 between two adjacent light-emitting chips 41. The
conductive line 23 electrically connects the first pads 301 of two
adjacent light-emitting chips 41. The symbol of conductive line 23
in FIG. 1B represents one or more connecting segments 231 and a
stretchable segment 232 as shown in FIG. 1B. A plurality of second
trenches 112 is also formed on the other side of the substrate 11
opposite to the first trenches 111. The trench 111, 112 can be
formed at the outermost surface of the substrate 11 by laser or
within the substrate 11 by SD (Stealth Dicing) laser. It is noted
that a scarified layer 24 is optionally formed between the
conductive line 23 and the substrate 11 at a position corresponding
to the first trench 111, the second trench 112, or both. The
position of the trench 111 corresponding to the substrate 11 and
the position of the trench 112 corresponding to the substrate 11
can be the same or different. The first-type semiconductor layer
311 and the second-type semiconductor layer 313 respectively
provide electrons and holes such that electrons and holes can be
combined in the active layer 312 to emit light. The active layer
312 can be made of AlxInyGa(1-x-y)P, wherein 0.ltoreq.x,
y.ltoreq.1; (x+y).ltoreq.1, to emit a red light with a peak
wavelength within a range between 610-650 nm; can be made of
AlxInyGa(1-x-y)N, wherein 0.ltoreq.x, y.ltoreq.1; (x+y).ltoreq.1,
to emit a green light with a peak wavelength within a range between
530-570 nm; or can be made of AlxInyGa(1-x-y)N, wherein 0.ltoreq.x,
y.ltoreq.1; (x+y).ltoreq.1, to emit a blue light with a peak
wavelength within a range between 450-490 nm. It is noted that the
light-emitting chips 41 in the light-emitting array can emit
different light. For example, one of the light-emitting chips 41
can emit a red light, and one of the light-emitting chips 41 can
emit a blue light.
[0042] FIG. 1C shows a cross-sectional view along V-V' line in FIG.
1A. The conductive line 23 electrically connects the second pads
302 of two adjacent light-emitting chips 41 with each other. Before
stretching, the light-emitting chips 41 are separated by the trench
111, 112 such that a plurality of separated light-emitting elements
40 as shown in FIGS. 1D and 7F is formed. A detail process is
described below.
[0043] FIG. 1D shows a top view of the light-emitting array of the
first embodiment in a stretched state. After forming a plurality of
the light-emitting elements 40, a force is applied to the
conductive line 23 or the light-emitting elements 40 in the X
direction to stretch the stretchable segment 232. The
light-emitting elements 40 are therefore moved away from each
other, and the light-emitting elements 40 are separated by a
distance (D2) larger than the distance (D1) in FIG. 1A in the X
direction. As shown in FIGS. 1D and 1A, it is noted that the
stretchable segment 232 has a length (L3) similar or equal to the
length (L1). In other words, the length of the stretchable segment
232 is almost kept unchanged before and after stretching. The
stretchable segment 232 is designed to have a curved or sinuous
shape at initial, as illustrated in FIG. 1A, and the stretchable
segment 232 is then to be stretched to be a straight line as shown
in FIG. 1D. The stretched stretchable segment 232 can have a shape
including but not limited to a straight line, a curved line, and a
combination thereof. Moreover, the curved line can have one or more
curvatures. The distance (D2) or a length of the stretchable
segment 232 after stretching or a distance (D3) between two
adjacent connecting segments 231 has a maximum value while the
stretchable segment 232 is stretched to a maximum extent but not
beyond its elastic limit. Therefore, the longer the length (L1),
the larger the distance between two adjacent light-emitting
elements 40 can be. In one embodiment, the distance (D3) can be in
a range between a length in the un-stretched state (see FIG. 1A)
and a length in the stretched state (see FIG. 1D), depending on
requirements. It is noted that when the conductive line 23 is made
of a rigid and elastic material, a line width of the stretchable
segment 232 can be substantially the same before and after
stretching. When the conductive line 23 is made of a ductile and
malleable material, a line width of the stretchable segment 232
after stretching can be narrower than that before stretching. In an
embodiment, the stretchable segment 232 has a line width of 5-15
.mu.m before stretching and the stretchable segment 232 has a line
width of 4-15 .mu.m after stretching. The conductive line 23 is
made of an elastic material, such as Cu, Al, Ag, Au or alloy
thereof. In an embodiment, a ratio between the distance of two
parallel conductive lines 23 arranged in X direction and a width of
the light-emitting elements 40 in X direction is between 2 to 10.
Likewise, another force is applied to the conductive line 23 or the
light-emitting elements 40 in a Y direction to stretch the
stretchable segment 232 of the conductive line 23, the
light-emitting elements 40 are therefore moved away from each
other. The light-emitting elements 40 are separated by a distance
(D4) larger than the distance (D1) in FIG. 1A in the Y direction.
As shown in FIGS. 1D and 1A, the stretchable segment 232 has a
length (L4) similar to or equal to the length (L2). In other words,
the length of the stretchable segment 232 is almost kept unchanged
before and after stretching. The stretchable segment 232 has a
curved or sinuous shape, as illustrated in FIG. 1A, however, the
stretchable segment 232 is deformed to become a straight line in
FIG. 1D. The stretched stretchable segment 232 can have a shape
including but not limited to a straight line, a curved line, and a
combination thereof. Moreover, the curved line can have one or more
curvatures. A distance (D4) or a length of the stretchable segment
232 after stretching or a distance (D5) between the two first
segments 231 of adjacent light-emitting elements 40 has a maximum
value while the stretchable segment 232 is stretched to a maximum
extent but not beyond its elastic limit. Therefore, the longer the
length (L2), the larger the distance between two adjacent
light-emitting elements 40 can be. In one embodiment, the distance
(D5) can be in a range between a length in the un-stretched state
(see FIG. 1A) and a length in the stretched state (see FIG. 1D),
depending on the actual requirements.
[0044] The process of manufacturing the structures in FIGS.
1A.about.1D is shown in FIGS. 1E.about.1I. Referring to FIGS.
1E.about.1F, the light-emitting chips 41 are formed on a first
growth substrate 13a (or located on a first temporary substrate),
and the conductive lines 23 are formed on a second growth substrate
13b (or located on a second temporary substrate). Referring to
FIGS. 1G.about.1I, the light-emitting chips 41 and the conductive
lines 23 are connected to each other; then, the first growth
substrate 13a and the second growth substrate 13b are sequentially
removed.
[0045] FIG. 2A shows a top view of a light-emitting array in an
un-stretched state in accordance with a second embodiment of the
present invention. The light-emitting array of the second
embodiment has a structure similar to that illustrated in the first
embodiment. Compared with FIG. 1A, a larger distance is formed
between two adjacent light-emitting chips 41, and the length of the
stretchable segment 232 is increased.
[0046] FIG. 2B shows a top view of the light-emitting array of the
second embodiment in a stretched state. Compared with FIG. 1A,
since the length of the stretchable segment 232 is increased to be
the un-stretched state, two adjacent light-emitting elements 40 can
be separated by a longer distance (D6) in the X direction (for
example, D6 is larger than D2 depicted in FIG. 1D), in the Y
direction, or in both direction after stretching. FIG. 2C shows a
cross-sectional view taken along U-U' line in FIG. 2A, and FIG. 2D
shows a cross-sectional view taken along V-V' line in FIG. 2A. As
the same as shown in FIG. 1B and FIG. 1C, the trenches 111, 112 are
formed on opposite side of the substrate 11; but there is no
scarified layer 24 formed between the substrate 11 and the
conductive line 23.
[0047] FIG. 3A shows a top view of a light-emitting array in an
un-stretched state in accordance with a third embodiment of the
present invention. The light-emitting array of the third embodiment
has a structure similar to that illustrated in the first
embodiment. In this embodiment, the stretchable segment 232
connected between two light-emitting chips 41 has a portion 2321
extending above another light-emitting chip 41 which is not
physically connected to the stretchable segment 232.
[0048] FIG. 3B shows a top view of a light-emitting array in an
un-stretched state in accordance with a fourth embodiment of the
present invention. The light-emitting array of the fourth
embodiment has a structure similar to that illustrated in the
second embodiment. The light-emitting chip 41 has a rectangular
shape and four corners, and the pads of the light-emitting chip 41
are formed on the four corners respectively. The two first pads 301
are arranged on diagonal corners (a first corner and a second
corner). The second pad 302 is arranged to extend from a third
corner to a fourth corner. In this embodiment, the second pad 302
is connected to the conductive lines 23 to provide electrical
connection in a direction along the U-U' line, and the first pads
301 are connected to the conductive lines 23 to provide electrical
connection in a direction along the V-V' line.
[0049] According to the embodiments shown in FIGS. 3A-3B, the
conductive line 23 can be formed in various shape for different
application. In addition, the distance between two adjacent LED
units can be modified by adopting proper conductive line. For
example, the line part can be a zig-zag type, a repeated "S-shaped"
type, or a spiral type, etc. As a result, the space between two
adjacent pads of different light-emitting elements 40 is more
effectively utilized to dispose the conductive wire therein. FIGS.
3C-3D show two embodiments in accordance with the present
application. FIG. 3C is an enlarged view of two adjacent
light-emitting elements 40 and the conductive line 23 between them.
The conductive line 23 is curved as a repeated "F-shaped" or
repeated "7-shaped" as shown in FIG. 3C. Specifically, the
conductive line 23 includes multiple stretchable segments 232,
straight portions 233 between stretchable segments, and bending
portions 234. The repeated "F-shaped" or repeated "7-shaped" of the
conductive line 23 is formed by a repeated sequence of a bending
portion 234, a straight portion 233, a stretchable segments 232, a
straight portion 233, and another bending portion 234. Such that,
the conductive line 23 includes multiple combinations of "bending
portions 234--straight portion 233--stretchable segments
232--straight portion 233--bending portions 234" arranged to be
perpendicular to each other. As a result, the space between two
adjacent pads of different LED cells is more effectively utilized
to dispose the conductive wire therein. In another embodiment, the
combinations can be arranged alternately. Referring to FIG. 3D, the
conductive line 23 is curved as a repeated "8-shape".
[0050] In addition, the conductive lines 23 are extended by
external force, so the conductive wires should be strengthened to
prevent broken caused by the external force. FIG. 3E is a top view
of the conductive line 23 before being extended. In order to
enhance the connecting strength between the connecting segments 231
and the stretchable segment 232, the contact area of the connecting
segments 231 and the pad is increased. The width of the connecting
segment 231 is larger than the width of the stretchable segments
232. The pattern of the connecting segment 231 can be a dot, a
square, or a similar shape with the pads of a light-emitting chip,
etc. As shown in FIG. 3E, the stretchable segments 232 of the
conductive line 23 includes a first bending portion A and a second
bending portion B. The curvature radius of the first bending
portion A and the second bending portion B are represented as
R.sub.A and R.sub.B, respectively. W is the width of the
stretchable segments 232. The dotted line X-X' is the direction
along two connecting segments 231. L is the distance between the
vertex 235 of bending portion A and the vertex 236 of bending
portion B on a projecting direction which is perpendicular to line
X-X', wherein L is larger than the sum of curvature radius R.sub.A
and curvature radius R.sub.B. Besides, the ratio of W to L (i.e.
W/L) is varied within a range of 0.1 and 0.4, such as 0.2, 0.15,
0.3 and 0.38. In another embodiment, the ratio (W/L) can be less
than 0.1 or larger than 0.4 for different application and different
material of the conductive line applied. In this embodiment, the
value of W/L is limited within the range, and the LED array will
not be difficult to extend and the conductive line 23 will not be
cracked easily when external force applied. Referring to FIG. 3F,
an embodiment of the conductive line 23 with a repeated regular
S-shape is shown. The curvature radius of each vertex is
substantially the same, and the vertical distance L between two
vertexes on opposite site of the conductive line 23 substantially
remains a constant. The value of W/L also satisfies the criteria
described above.
[0051] However, though the ratio between the width W of stretchable
segments 232 and distance L between the vertex 235 of bending
portion A and the vertex 236 is concerned, some modification is
added for better reliability. Referring to FIG. 1A, the electrical
connection between light-emitting chips 41 in X direction is
provided by a conductive line 23 B1-Bn continuously extended in X
direction. The electrical connection between light-emitting chips
41 in Y direction is provided by conductive lines 23 A1-An which
are discontinuously extended in Y direction. In the embodiment
shown in FIG. 1A, the connection strength in X direction is larger
than the strength in Y direction because each of the area of pad
231 connecting to the second pad 302 is larger than the area of pad
231 connecting to the first pad 301. So, the area of pad 231
connecting to the first pad 301 is expected to be large than the
area of pad 231 connecting to the second pad 302 for better
connection strength in Y direction. In another embodiment, the area
of the pad 231 connecting to the first pad 301 is 1-1.6 times the
area of the pad 231 connecting to the second pad 302.
[0052] FIG. 4A shows a top view of a light-emitting array in an
un-stretched state in accordance with an embodiment of the present
invention. The light-emitting array includes a plurality of
light-emitting groups on a substrate 11. Each of the light-emitting
groups includes a red light-emitting chip 41R, a green
light-emitting chip 41G, and a blue light-emitting chip 41B. The
red light-emitting chip 41R has two first pads 301R and a second
pad 302R, and the substrate 11 includes scribing lines 110 between
two of the light-emitting groups. One of the first pads 301R of the
red light-emitting chip 41R is electrically connected to another
first pad 301R of adjacent red light-emitting chip 41R by the
conductive line 23R. Likewise, the green light-emitting chip 41G
has two first pads 301G and a second pad 302G. One of the first
pads 301G of the green light-emitting chip 41G is electrically
connected to another first pad 301G of an adjacent green
light-emitting chip 41G by the conductive line 23G. The blue
light-emitting chip 41B has two first pads 301B and a second pad
302B. One of the first pads 301B of the blue light-emitting chip
41B is electrically connected to another first pad 301B of an
adjacent blue light-emitting chip 41B by the conductive line 23B. A
common pad 302C is formed on and to connect to the second pads
302R, 302G and 302B in one light-emitting group. The conductive
line 23C is formed to connect the common pad 302C of a
light-emitting group with the common pad 302C of an adjacent
light-emitting group. As described in FIG. 1A, by selectively
connecting the conductive line (23R, 23G, 23B, 23C) with the
external element. The specific light-emitting chip (41R, 41G, or
41B) can emit light. In this embodiment, the light-emitting chips
(41R, 41G, and 41B) are epitaxially grown on the substrate 11. The
red light-emitting chip 41R can be optionally formed by using a red
phosphor on a blue or UV light-emitting chip to emit a red light
with a wavelength of 610-650 nm; and the green light-emitting chip
41G can be optionally formed by using a green phosphor on a blue or
UV light-emitting chip to emit a green light with a wavelength of
530-570 nm. The blue light-emitting chip 41B can be optionally
formed by using a blue phosphor on a UV light-emitting chip to emit
a blue light with a wavelength of 450-490 nm. Each of the
light-emitting group can be used as a pixel in a display or a
backlight in a display. In this embodiment, one light-emitting
group has three red light-emitting chips 41R, three green
light-emitting chips 41G, and three blue light-emitting chips 41B.
In another embodiment, one light-emitting group includes one
light-emitting chip or two light-emitting chips of different
colors.
[0053] FIG. 4B shows a top view of the light-emitting array of an
embodiment in a stretched state. FIG. 4C shows a cross-sectional
view of an embodiment shown in FIG. 4A. Before stretching, the
light-emitting groups are separated from each other. The separated
light-emitting groups are formed on the substrate 11. The substrate
11 is separated into several pieces as common substrates. Referring
to FIG. 4C, the light-emitting chips 41R, 41G, and 41B of one
light-emitting group are formed on one common substrate 101, and
the light-emitting group on one common substrate 101 is connected
to another light-emitting group on another common substrate
101.
[0054] FIG. 4D shows a top view of a light-emitting array in an
un-stretched state in accordance with a further embodiment of the
present invention. FIG. 4E shows a cross-sectional view of a
light-emitting group in accordance with an embodiment of the
present invention. The light-emitting array of the sixth embodiment
has a structure similar to that illustrating in FIG. 4A. Referring
to FIG. 4D, the common pad 302C is formed on the light-emitting
group. Referring to FIG. 4E, the common pad 302C is directly formed
on the semiconductor layers 313 of the light-emitting chips 41R,
41G, and 41B without second pads formed therebetween. Referring to
FIG. 4C, the second pads 302R, 302G and 302B of the light-emitting
chips 41R, 41G, 41B are formed between the semiconductor layers 313
and the common pad 302C.
[0055] FIG. 5A shows a top view in an un-stretched state in
accordance with an embodiment of the present invention. There are
three light-emitting arrays including a red light-emitting array, a
green light-emitting array, and a blue light-emitting array. Each
light-emitting array can have a structure as shown in FIG. 1A, 2A,
or 3A. Specifically, the red light-emitting array includes a
plurality of red light-emitting elements 40R, the green
light-emitting array includes a plurality of the green
light-emitting elements 40G, and the blue light-emitting array
includes a plurality of the blue light-emitting elements 40B. Two
adjacent red light-emitting elements 40R are electrically connected
to each other by the conductive line 23R, two adjacent green
light-emitting elements 40G are electrically connected to each
other by the conductive line 23G, and two adjacent blue
light-emitting elements 40B are electrically connected to each
other by the conductive line 23B. The three light-emitting arrays
are spatially arranged such that the conductive lines 23R, 23G, 23B
do not penetrate each other. In other words, the light-emitting
elements 40R, 40G and 40B are arranged in different elevations (see
FIG. 5C). In addition, the three light-emitting arrays are
alternately arranged such that, in a top view, the light-emitting
elements 40R, 40G and 40B are formed in a repeated configuration of
blue-green-red pattern in a two dimensional plane. One
blue-green-red pattern is used as a pixel in a display. A
transparent material, such as silicone, epoxy, polyimide (PI), BCB,
perfluorocyclobutane (PFCB), Su8, acrylic resin, polymethyl
methacrylate (PMMA), polyethylene terephthalate (PET),
polycarbonate (PC), polyetherimide, or fluorocarbon polymer, can be
filled among the three light-emitting arrays.
[0056] FIG. 5B shows a cross-sectional view along the line A-A' in
FIG. 5A. The red light-emitting element 40R can have an active
layer made of AlxInyGa(1-x-y)P, wherein 0.ltoreq.x, y.ltoreq.1;
(x+y).ltoreq.1, to emit a red light with a wavelength of 610-650
nm; the green light-emitting element 40G can have an active layer
made of AlxInyGa(1-x-y)N, wherein 0.ltoreq.x, y.ltoreq.1;
(x+y).ltoreq.1, to emit a green light with a wavelength of 530-570
nm; and the blue light-emitting element 40B can have an active
layer made of AlxInyGa(1-x-y)N, wherein 0.ltoreq.x, y.ltoreq.1;
(x+y).ltoreq.1, to emit a blue light with a wavelength of 450-490
nm. Moreover, a frame (not shown) is provided to interpose between
any two of the light-emitting elements to avoid a light absorption
or cross talk therebetween. FIG. 5C shows a cross-sectional view
taken along the line B-B' in FIG. 5A. The light-emitting elements
40R, 40G and 40B are arranged in different elevations. The
light-emitting element 40B is arranged at an elevation higher than
the light-emitting element 40G, and the light-emitting element 40G
is arranged at an elevation higher than the light-emitting element
40R.
[0057] In addition, a control element can be added to the
embodiment shown in FIG. 5A to control each of the light-emitting
elements. FIGS. 5D-5H show an embodiment of a control element in
accordance with present application. Referring to FIG. 5D, a
control element 23CR is connected to the conductive lines 23R, and
a control line 33R is connected to the control element 23CR. The
light-emitting element 40R is designed to be electrically powered
by the conductive lines 23R shown FIG. 5A. Then, the control
element 23CR, such as a transistor, is added to control the
light-emitting element 40R shown in FIG. 5D. In this embodiment,
the control line 33R is served as the gate of the control element
23CR and the conductive line 23R is served as the drain and source
of the control element 23R. The control element 23CR is turned on
while a control signal is provided to the control element 23R
through the control line 33R. Thus, the control line 33R is
controlled to be at a high level, and the current from the pad 301R
is transmitted to the light-emitting element 40R through the
conductive line 23R. FIGS. 5E-5H show the top views and
cross-sectional views of the process of manufacturing the control
element 23CR in accordance with an embodiment of the present
invention. Referring to FIG. 5E, a conductive line 33, which can be
connected to the control line 33R shown in FIG. 5D, is formed on
the substrate 11. In another embodiment, the conductive line 33 and
the control line 33R can be formed at once. Referring to FIG. 5F, a
dielectric layer 330 is provided on the conductive line 33 to cover
the top surface and the sidewalls of the conductive line 33.
Referring to FIGS. 5G-5H, the active layers 33A with a doped
semiconductor layer is formed on the dielectric layer 330 to be
connected to the conductive line 23R. The active layer 33A includes
one or more doped layers of the same or different conductive types.
Moreover, the doping concentrations of the doped layers can be the
same or different. A similar structure of a control element 23CR
can also be applied to control other light-emitting elements, such
as light-emitting elements 40G and light-emitting elements 40B.
Besides, the control element 23CR can be formed to connect the
conductive line 23R along the line A-A' or formed along the line
B-B'. One control element can be used to control one light-emitting
element with a control signal provided through a control line as
shown in previous embodiment. In anther embodiment, one control
element can be used to control two or more light-emitting elements
by providing one or more control signals. With the adoption of the
control elements, the light-emitting array can be used as a display
to show required pictures or images.
[0058] FIG. 6A shows a top view of a light-emitting array in an
un-stretched state in accordance with an embodiment of the present
invention. The light-emitting array includes a plurality of
light-emitting units 30. Each of the light-emitting units 30 has a
light-emitting element 40. The structure of the light-emitting unit
30 is described below. The electrical connection between the
light-emitting units 30 can be derived from the aforementioned
teaching and therefore is omitted herein for brevity.
[0059] FIG. 6B shows a top view of a light-emitting array in an
un-stretched state in accordance with an embodiment of the present
invention. The light-emitting array is a 1-dimension array and
includes a plurality of light-emitting units 30. Each of the
light-emitting units 30 has a light-emitting element 40. The
light-emitting element 40 has a first pad 301 and a second pad 302.
The first pad 301 of one of the light-emitting elements 40 is
connected to the second pad 302 of adjacent one of the
light-emitting element 40 by the conductive line 23 such that the
light-emitting elements 40 or the light-emitting units 30 are
electrically connected to each other in series. The structure of
the light-emitting unit 30 is described below. A detail of the
conductive line 23 can be derived from the aforementioned teaching
and therefore is omitted herein for brevity. The structure shown in
FIGS. 5D-5H can be applied to embodiments shown in FIGS. 6A-6B.
That is, the control element 23CR can be used to control
light-emitting units 30 in the 2-dimensional light-emitting array
as shown in FIG. 6A or in the 1-dimensional light-emitting array
shown in FIG. 6B.
[0060] FIGS. 7A-7G illustrate steps of making the light-emitting
array related to the first embodiment of the application. It is
noted that FIGS. 7A-7G illustrate steps of making the conductive
line 23 along the V-V' line, but the conductive line 23 along the
U-U' line can be formed by the same making steps. As shown in FIG.
7A, a plurality of spaced-apart light-emitting chips 41 are located
on a substrate 11. The substrate 11 is situated on a temporary
substrate 12. Each second pad 302 of the light-emitting chips 41 is
exposed. A seed layer 21 is fully formed on the light-emitting
chips 41 and the substrate 11. A recess region 211 of the seed
layer 21 locates at a position between two adjacent light-emitting
chips 41. In this embodiment, the seed layer 21 is not fully filled
in a space between two adjacent light-emitting chips 41 and
therefore air may exist in the space. A trench 111 is formed on the
substrate 11 at a position substantially corresponding to the
recess region 211.
[0061] As shown in FIG. 7B, a patterned layer 22, such as a
photoresistor layer, is formed on the seed layer 21 to expose the
seed layer 21 at a position corresponding to the second pads 302
and to expose the seed layer 21 at portions corresponding to the
recess region 211. As shown in FIG. 7C, a conductive line 23 is
formed on the exposed seed layer 21 which is not covered by the
patterned layer 22. The conductive line 23 has a connecting segment
231 formed on the second pad 302 of one light-emitting chip 41,
another connecting segment 231 formed on the second pad 302 of
adjacent one light-emitting chip 41, and a stretchable segment 232
located between the adjacent connecting segments 231. As shown in
FIGS. 7D-7E, the patterned layer 22 and the seed layer 21 are
sequentially removed. The area of the seed layer 21 below the
connecting segment 231 is larger than that below the stretchable
segment 232. The portion of the seed layer 21 below the stretchable
segment 232 can be totally removed. The portion of the seed layer
21 below the connecting segment 231 is not fully removed and part
of the portion below the connecting segment 231 is preserved.
Therefore, the first segment 231 and the second segment 233 are
still connected to the light-emitting chips 41, and the stretchable
segment 232 is suspended.
[0062] As shown in FIG. 7F, the temporary substrate 12 is removed
and the substrate 11 is divided along the trench 111 to form a
plurality of light-emitting elements 40. Then, the plurality of
light-emitting elements 40 is stretched as shown in FIG. 1D and
FIG. 7G. A force is applied to stretch the stretchable segment 232
and to enlarge a space between the light-emitting elements 40.
[0063] FIGS. 8A-8G show the manufacturing steps related to the
embodiment shown in FIG. 6B, but the light-emitting units 30 are
spaced apart from each other and are not arranged to abut against
each other. As shown in FIG. 8A, a plurality of spaced-apart
light-emitting units 30 are formed on a temporary substrate 12. The
first pad 301 and the second pad 302 in each light-emitting unit 30
are exposed. A seed layer 21 is fully formed on the light-emitting
units 30 and the temporary substrate 12. The seed layer 21 is
located at a position between two adjacent light-emitting units 30
and has a recess region 211. In addition, the seed layer 21 cannot
be fully filled in a space between two adjacent light-emitting
units 30, and air may exist in the space. As shown in FIG. 8B, a
patterned layer 22, such as a photoresistor layer, is formed on the
seed layer 21 to expose the seed layer 21 at a position
corresponding to the first pad 301 and the second pad 302, and to
expose the seed layer 21 at portions corresponding to the recess
region 211.
[0064] As shown in FIG. 8C, a conductive line 23 is formed on the
exposed seed layer 21 which is not covered by the patterned layer
22. The conductive line 23 has a connecting segment 231 formed on
the first pad 301 of one light-emitting chip, a connecting segment
233 formed on the second pad 302 of adjacent one light-emitting
chip, and a stretchable segment 232 extended between the first
segment 231 and the second segment 233.
[0065] As shown in FIG. 8D-8E, the patterned layer 22 and the seed
layer 21 are removed. The area of the seed layer 21 below the
connecting segment 231 is larger than that below the stretchable
segment 232. The portion of the seed layer 21 below the stretchable
segment 232 can be totally removed, and the portion of the seed
layer 21 below the connecting segment 231 are not fully removed and
part of the portion below the connecting segment 231 is preserved.
Therefore, the connecting segments 231 and the stretchable segment
232 are still connected to the light-emitting units 30, and the
stretchable segment 232 is suspended.
[0066] As shown in FIGS. 8F-8G, the temporary substrate 12 is
removed, and a force is applied to stretch the stretchable segment
232 of the conductive line 23 and to enlarge a space between the
light-emitting units 30. The process in FIGS. 7A-7G or FIGS. 8A-8G
can be applied to aforementioned embodiments.
[0067] It is noted that the light-emitting element in the
aforementioned embodiments have the first pad 301 and the second
pad 302 on the same side of the substrate which is defined herein
as a horizontal-type light-emitting element. However, a
vertical-type light-emitting element can be used. The vertical-type
light-emitting element is defined herein that the first pad 301 and
the second pad 302 are formed on the opposite sides of the
substrate. FIG. 9A shows a cross-sectional view in accordance with
an embodiment of the present invention where the vertical-type
light-emitting element is illustrated. Each of the light-emitting
elements 40 has a light-emitting stack which includes a first-type
semiconductor layer 311, an active layer 312, and a second-type
semiconductor layer 313. The first pad 301 is formed on the
conductive substrate 102 (SiC, GaN, GaAs, TiW, or Cu). The second
pad 302 is formed on the second-type semiconductor layer 313. A
conductive line 23 is provided to electrically connect the first
pads 301 of the light-emitting elements 40. Another conductive line
23 is provided to electrically connect the second pads 302 of the
light-emitting elements 40 with each other. The two conductive
lines 23 are formed on opposite sides of the conductive substrate
102. The structure shown in FIGS. 5D-5H can be applied to
embodiments shown in FIG. 9A. That is, the structure with a control
element and control line(s) can be used to control horizontal-type
light-emitting element or vertical-type light-emitting element.
Specifically, the control element can be connected to the
conductive line 23 which is directly connected to the first pads
301 or the conductive line 23 which is directly connected to the
second pads 302. The control lines can be formed on a side same as
the control element or on a side opposite to the light-emitting
stack in FIG. 9A.
[0068] The process of manufacturing the structures shown in FIG. 9A
is illustrated in FIGS. 9B-9E. Referring to FIGS. 9B-9C, a
light-emitting stack including a first-type semiconductor layer
311, an active layer 312, and a second-type semiconductor layer 313
is provided with a first pads 301 and a second pads 302 which are
respectively connected to the first-type semiconductor layer 311
and the second-type semiconductor layer 313; and a conductive line
23 is provided on a temporary substrate. Referring to FIGS. 9D-9E,
two conductive lines 23 are attached to the first pad 301 and the
second pad 302 of the light-emitting stack, and the temporary
substrate is then removed to form a structure as shown in FIG.
9A.
[0069] FIGS. 10A-10F show a structure of the light-emitting unit 30
in accordance with the present invention. Referring to FIG. 10A,
the light-emitting unit 30 includes a first transparent structure
52 enclosing the light-emitting element 40, a second transparent
structure 51 formed on the first transparent structure 52. A
reflective layer 53 is formed on the first transparent structure 52
opposite to the second transparent structure 51 and has a first
portion 531 and a second portion 532 between the first pad 301 and
the second pad 302. In this embodiment, the first portion 531 has a
curved shape and a profile with a height gradually increasing from
the light-emitting element 40 to an edge, away from the
light-emitting element 40, of the first transparent structure 52.
Besides, the second portion 532 also has a curved shape and a
profile with a central region bulging away from the light-emitting
element 40. A first enlarged pad 541 is formed on the first portion
531 and electrically connected to the first pad 301. A second
enlarged pad 542 is formed on the first portion 531 and
electrically connected to the second pad 302. In this embodiment,
the first enlarged pad 541 (or the second enlarged pad 542) has a
curve sidewall 5411.
[0070] As shown in FIG. 10B, the light-emitting unit 30 has a
structure similar to that shown in FIG. 10A, except that a phosphor
layer 55 is provided within the first transparent structure 52.
[0071] As shown in FIG. 10C, the light-emitting unit 30 has a
structure similar to that shown in FIG. 10A, except that the second
transparent structure 51 has a slanted sidewall 511.
[0072] As shown in FIG. 10D, the light-emitting unit 30 has a
structure similar to that in FIG. 10C, except that a phosphor layer
55 is provided within the first transparent structure 52.
[0073] As shown in FIG. 10E, the light-emitting unit 30 has a
structure similar to that in FIG. 10A, except that the first
transparent structure 52 extends beyond the second transparent
structure 51 and has an arc 521 close to the second transparent
structure 51.
[0074] As shown in FIG. 10F, the light-emitting unit 30 has a
structure similar to that in FIG. 10E, except that a phosphor layer
55 is provided within the first transparent structure 52.
[0075] FIGS. 11A-11F show a structure of the light-emitting unit 30
in accordance with the present invention. FIGS. 11A-11F
respectively show a structure similar with those in FIGS. 10A-10F,
except that the light-emitting unit 30 in these embodiments does
not have the reflective layer and the enlarged pad.
[0076] FIGS. 12A-12G show a structure of the light-emitting unit 30
in accordance with the present invention. FIGS. 12A and 12B have a
structure similar to those shown in FIGS. 10E and 10F, except that
a reflective structure 56, for example a DBR structure, is formed
between the first transparent structure 52 and the second
transparent structure 51. FIGS. 12C and 12D have a structure
similar to those in FIGS. 10A and 10B, except that the
light-emitting unit 30 is devoid of the second transparent
structure 51 formed on the first transparent structure 52. FIGS. 12
E and 12F have a structure similar to those in FIGS. 12C and 12D,
except that the light-emitting unit 30 does not have the reflective
layer 53 and the enlarged pad 541 and 542. FIG. 12G has a structure
similar to that in FIG. 12F, except that the phosphor 55 is
conformably formed on the light-emitting element 40.
[0077] FIGS. 13A and 13B show a structure of the light-emitting
unit 30 in accordance with the present invention. As shown in FIG.
13A, a phosphor structure 57 encloses the light-emitting element
40. FIG. 13B has a structure similar to that in FIG. 13A, except
that the reflective layer 53 and the enlarged pad 541, 542 are
provided.
[0078] It will be apparent to those having ordinary skill in the
art that various modifications and variations can be made to the
devices in accordance with the present disclosure without departing
from the scope or spirit of the disclosure. In view of the
foregoing, it is intended that the present disclosure covers
modifications and variations of this disclosure provided they fall
within the scope of the following claims and their equivalents.
* * * * *