U.S. patent application number 11/953736 was filed with the patent office on 2008-04-17 for method of manufacturing light emitting element and method of manufacturing display apparatus having the same.
Invention is credited to Joon-Hoo Choi, Jin-Koo Chung, Dong-Won Lee.
Application Number | 20080090484 11/953736 |
Document ID | / |
Family ID | 34698414 |
Filed Date | 2008-04-17 |
United States Patent
Application |
20080090484 |
Kind Code |
A1 |
Lee; Dong-Won ; et
al. |
April 17, 2008 |
Method of manufacturing light emitting element and method of
manufacturing display apparatus having the same
Abstract
In a method of manufacturing a light emitting element, a
plurality of first electrodes arranged in a matrix shape is formed
on a pixel area of a base substrate. A bank is formed between the
first electrodes. A light emitting material is ejected on a portion
of the first electrodes spaced apart from one another to form a
plurality of first light emitting patterns. The light emitting
material is erected on a portion of the first electrodes between
the first light emitting patterns to form a plurality of second
light emitting patterns. A second electrode is formed on the first
and second light emitting patterns. Therefore, a luminance of the
light emitting element is improved and uniformized.
Inventors: |
Lee; Dong-Won; (Seongnam-si,
KR) ; Choi; Joon-Hoo; (Seoul, KR) ; Chung;
Jin-Koo; (Suwon-si, KR) |
Correspondence
Address: |
F. CHAU & ASSOCIATES, LLC
130 WOODBURY ROAD
WOODBURY
NY
11797
US
|
Family ID: |
34698414 |
Appl. No.: |
11/953736 |
Filed: |
December 10, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11017532 |
Dec 20, 2004 |
7326584 |
|
|
11953736 |
Dec 10, 2007 |
|
|
|
Current U.S.
Class: |
445/49 |
Current CPC
Class: |
H01L 27/3244 20130101;
H01L 27/3246 20130101; H01L 27/3211 20130101; H01L 51/56 20130101;
H01L 51/0005 20130101 |
Class at
Publication: |
445/049 |
International
Class: |
H01J 9/14 20060101
H01J009/14 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 19, 2003 |
KR |
2003-93741 |
Claims
1. A method of manufacturing a light emitting element comprising:
forming a plurality of first electrodes arranged in a matrix shape
on a pixel area of a base substrate; forming a bank between the
first electrodes; ejecting a light emitting material on a portion
of the first electrodes spaced apart from one another to form a
plurality of first light emitting patterns; ejecting the light
emitting material on a portion of the first electrodes between the
first light emitting patterns to form a plurality of second light
emitting patterns; forming a second electrode on the first and
second light emitting patterns; and forming a plurality of dummy
light emitting patterns on a peripheral region of the base
substrate, and wherein the peripheral region surrounds the pixel
area.
2. The method of claim 1, wherein the second light emitting
patterns comprise substantially identical color to the first light
emitting patterns.
3. The method of claim 1, further comprising ejecting the light
emitting material on a portion of the first electrodes between the
first and second light emitting patterns to form a plurality of
third light emitting patterns.
4. The method of claim 1, wherein the first and second light
emitting patterns are arranged in a random order.
5. The method of claim 1, wherein the light emitting material
comprises an organic light emitting material and a volatile
material, and an evaporation rate of the volatile material of the
first light emitting patterns is substantially equal to an
evaporation rate of the volatile material of the second light
emitting patterns.
6. A method of manufacturing a light emitting element comprising:
forming a plurality of first electrodes arranged in a matrix shape
on a pixel area of a base substrate; forming a bank between the
first electrodes; ejecting a light emitting material on a portion
of the first electrodes spaced apart from one another to form a
plurality of first light emitting patterns; ejecting the light
emitting material on a portion of the first electrodes between the
first light emitting patterns to form a plurality of second light
emitting patterns; ejecting the light emitting material on a
portion of the first electrodes between the first and second light
emitting patterns to form a plurality of third light emitting
patterns; forming a second electrode on the first to third light
emitting patterns; and forming a plurality of dummy light emitting
patterns on a peripheral region of the base substrate, and wherein
the peripheral region surrounds the pixel area.
7. The method of claim 6, wherein the first to third light emitting
patterns comprise substantially identical color to one another.
8. The method of claim 6, wherein the first to third light emitting
patterns are arranged in a column direction of the matrix
shape.
9. The method of claim 8, wherein the first light emitting patterns
are formed on once in every two to thirty of the first
electrodes.
10. The method of claim 6, wherein the first and second light
emitting patterns are spaced apart from one another by a uniform
distance.
11. The method of claim 6, wherein forming of the first to third
light emitting patterns is repeated until the first to third light
emitting patterns are formed on all of the first electrodes.
12. The method of claim 11, wherein the first to third light
emitting patterns are arranged in a random order.
13. A method of manufacturing a display apparatus comprising:
forming a plurality of switching devices on a pixel area of a base
substrate; forming a plurality of driver devices on the pixel area
of the base substrate, a gate electrode of each of the driver
devices being electrically connected to a source/drain electrode of
each of the switching devices; forming a plurality of first
electrodes arranged in a matrix shape on the pixel area of the base
substrate; forming a bank between the first electrodes; ejecting a
light emitting material on a portion of the first electrodes spaced
apart from one another to form a plurality of first light emitting
patterns; ejecting the light emitting material on a portion of the
first electrodes between the first light emitting patterns to form
a plurality of second light emitting patterns; forming a second
electrode on the first and second light emitting patterns; and
forming a plurality of dummy light emitting patterns on a
peripheral region of the base substrate, and wherein the peripheral
region surrounds the pixel area.
14. The method of claim 13, wherein the second light emitting
patterns comprise substantially identical color to the first light
emitting patterns.
15. The method of claim 13, wherein the forming of the first and
second light emitting patterns is repeated, until the first and
second light emitting patterns are formed on all of the first
electrodes.
16. The method of claim 15, wherein the first and second light
emitting patterns are arranged in a random order.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Divisional of U.S. application Ser.
No. 11/017,532 filed on Dec. 20, 2004, which claims priority to
Korean Application No. 2003-93741 filed on Dec. 19, 2003, the
disclosure of which is hereby incorporated herein by reference in
its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method of manufacturing a
light emitting element and a method of manufacturing a display
apparatus having the light emitting element. More particularly, the
present invention relates to a light emitting element capable of
improving luminance and uniformity of the luminance and a method of
manufacturing a display apparatus having the light emitting
element.
[0004] 2. Description of the Related Art
[0005] A display apparatus, in general, converts data processed by
an information processing device into an image.
[0006] Display apparatuses includes a cathode ray tube (CRT)
apparatus, a liquid crystal display (LCD) apparatus, an organic
light emitting display (OLED) apparatus, a plasma display panel
(PDP) apparatus, etc. The CRT apparatus controls electrons that are
irradiated onto a fluorescent layer to display an image. The LCD
apparatus displays the image using a liquid crystal. The OLED
apparatus has a light emitting layer that generates a light using a
current. The PDP apparatus displays the image using plasma.
[0007] The OLED apparatus has various characteristics such as a
thin thickness, a high luminance, a good color reproducibility,
etc.
[0008] The OLED apparatus has a faster response speed, a better
color reproducibility, lower power consumption and a lower
manufacturing cost than the LCD apparatus. In addition, the OLED
apparatus may be operated at a lower temperature than the LCD
apparatus.
[0009] The OLED apparatus has a plurality of anodes arranged in a
matrix shape on a substrate, an organic layer having cavities,
light emitting patterns formed on the anodes in the cavities and a
cathode on the light emitting patterns.
[0010] Each of the light emitting patterns may have a positive
charge carrier injecting pattern, a light emitting pattern, etc.
The light emitting pattern may further have a negative charge
carrier injecting pattern.
[0011] The light emitting pattern may be formed through a spin
coating process, a roll-to-roll process, a vacuum deposition
process, etc. The light emitting pattern may be formed using a slit
mask. In addition, droplets having a light emitting material are
ejected in the cavities to form the light emitting pattern through
an inkjet method.
[0012] In a conventional inkjet method, the droplets are ejected
through nozzles in the cavities. An inkjet printer may use the
inkjet method.
[0013] All of the droplets may not be simultaneously ejected in all
of the cavities so that the inkjet method has a scanning process.
In the scanning process, a portion of the droplets is serially
ejected in a portion of the cavities.
[0014] When the droplets are ejected in the cavities using the
scanning process, evaporation rates of the droplets ejected in the
cavities are different from one another so that the light emitting
patterns have different profiles from one another.
[0015] When the profiles of the light emitting patterns are
different from one another, the OLED apparatus has non-uniform
luminance so that an image display quality of the OLED apparatus is
deteriorated.
SUMMARY OF THE INVENTION
[0016] The present invention provides a light emitting element
capable of improving luminance and uniformity of the luminance.
[0017] The present invention also provides a method of
manufacturing a display apparatus having the above-mentioned light
emitting element.
[0018] A method of manufacturing a light emitting element in
accordance with an aspect of the present invention is provided as
follows. A plurality of first electrodes arranged in a matrix shape
is formed on a pixel area of a base substrate. A bank is formed
between the first electrodes. A light emitting material is ejected
on a portion of the first electrodes spaced apart from one another
to form a plurality of first light emitting patterns. The light
emitting material is ejected on a portion of the first electrodes
between the first light emitting patterns to form a plurality of
second light emitting patterns. A second electrode is formed on the
first and second light emitting patterns.
[0019] A method of manufacturing a light emitting element in
accordance with another aspect of the present invention is provided
as follows. A plurality of first electrodes arranged in a matrix
shape is formed on a pixel area of a base substrate. A bank is
formed between the first electrodes. A light emitting material is
ejected on a portion of the first electrodes spaced apart from one
another to form a plurality of first light emitting patterns. The
light emitting material is ejected on a portion of the first
electrodes between the first light emitting patterns to form a
plurality of second light emitting patterns. The light emitting
material is ejected on a portion of the first electrodes between
the first and second light emitting patterns to form a plurality of
third light emitting patterns. A second electrode is formed on the
first to third light emitting patterns.
[0020] A method of manufacturing a display apparatus in accordance
with an aspect of the present invention is provided as follows. A
plurality of switching devices is formed on a pixel area of a base
substrate. A plurality of driver devices is formed on the pixel
area of the base substrate. A gate electrode of the driver device
is electrically connected to a source/drain electrode of the
switching device. A plurality, of first electrodes arranged in a
matrix shape is formed on the pixel area of the base substrate. A
bank is formed between the first electrodes. A light emitting
material is ejected on a portion of the first electrodes spaced
apart from one another to form a plurality of first light emitting
patterns. The light emitting material is ejected on a portion of
the first electrodes between the first light emitting patterns to
form a plurality of second light emitting patterns. A second
electrode is formed on the first and second light emitting
patterns.
[0021] The light emitting material may also be dropped or
discharged on the first electrodes.
[0022] Therefore, ejecting order of the light emitting material is
controlled so that evaporation rate of volatile material in the
light emitting material is not affected by adjacent light emitting
patterns. Therefore, thicknesses of the light emitting patterns are
uniformized so that luminance of the display apparatus is improved
and uniformized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The above and other advantages of the present invention will
become more apparent by describing in detail exemplary embodiments
thereof with reference to the accompanying drawings, in which:
[0024] FIG. 1 is a circuit diagram showing a display apparatus in
accordance with an exemplary embodiment of the present
invention;
[0025] FIG. 2 is a flow chart showing a method of manufacturing a
display apparatus in accordance with an exemplary embodiment of the
present invention;
[0026] FIG. 3 is a plan view showing first electrodes formed on a
base substrate in accordance with an exemplary embodiment of the
present invention;
[0027] FIG. 4 is a cross-sectional view taken along a line I-I' of
FIG. 3;
[0028] FIG. 5 is a cross-sectional view showing a bank formed
between the first electrodes of FIG. 3;
[0029] FIG. 6 is a plan view showing first light emitting patterns
formed on the base substrate of FIG. 5;
[0030] FIG. 7 is a cross-sectional view taken along a line II-II'
of FIG. 6;
[0031] FIG. 8 is a plan view showing second light emitting patterns
formed on the base substrate of FIG. 6;
[0032] FIG. 9 is a cross-sectional view taken along a line III-III'
of FIG. 8;
[0033] FIG. 10 is a plan view showing third light emitting patterns
formed on the base substrate of FIG. 8;
[0034] FIG. 11 is a cross-sectional view taken along a line IV-IV'
of FIG. 10;
[0035] FIG. 12 is a plan view showing green light emitting patterns
and blue light emitting patterns formed on the base substrate of
FIG. 10; and
[0036] FIG. 13 is a cross-sectional view showing a second electrode
formed on the base substrate of FIG. 12.
DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0037] It should be understood that the exemplary embodiments of
the present invention described below may be varied modified in
many different ways without departing from the inventive principles
disclosed herein, and the scope of the present invention is
therefore not limited to these particular following embodiments.
Rather, these embodiments are provided so that this disclosure will
be through and complete, and will fully convey the concept of the
invention to those skilled in the art by way of example and not of
limitation.
[0038] Hereinafter, the present invention will be described in
detail with reference to the accompanying drawings.
[0039] FIG. 1 is a circuit diagram showing a display apparatus in
accordance with an exemplary embodiment of the present
invention.
[0040] Referring to FIG. 1, the display apparatus includes a base
substrate 100 of FIG. 3 and a display circuit. The display circuit
has a switching device TFT1, a driver device TFT2, a light emitting
element 200, a storage capacitor C.sub.st, a gate bus line GBL, a
data bus line DBL and a power supplying line PSL. Alternatively,
the display circuit may have a plurality of switching devices, a
plurality of driver devices, a plurality of light emitting
elements, a plurality of storage capacitors, a plurality of gate
bus lines, a plurality of data bus lines and a plurality of power
supplying lines.
[0041] The gate bus line GBL is extended along a row direction. The
gate bus line GBL includes a metal having a low electric resistance
such as aluminum (Al), aluminum alloy, chromium (Cr), chromium
alloy, molybdenum (Mo), molybdenum alloy, titanium (Ti), titanium
alloy, tantalum (Ta), tantalum alloy, silver (Ag), silver alloy,
copper (Cu), copper alloy, etc. The gate bus line GBL includes a
gate electrode portion GE. The gate electrode portion GE is
protruded from the gate bus line GBL in the column direction.
[0042] The data bus line DBL is extended in the column direction.
The data bus line DBL includes a metal having a low resistance such
as aluminum (Al), aluminum alloy, chromium (Cr), chromium alloy,
molybdenum (Mo), molybdenum alloy, titanium (Ti), titanium alloy,
tantalum (Ta), tantalum alloy, silver (Ag), silver alloy, copper
(Cu), copper alloy, etc. The data bus line DBL includes a drain
electrode portion DE. The drain electrode portion DE is protruded
from the data bus line DBL in the row direction.
[0043] The power supplying line PSL is extended in the column
direction such that the power supplying line PSL is spaced apart
from the data bus line DBL. A voltage Vdd is applied to the power
supplying line PSL.
[0044] The switching device TFT1 and the driver device TFT2 are
disposed in a pixel region defined by the gate bus line GBL, the
data bus line DBL and the power supply line PSL.
[0045] The switching device TFT1 includes a first gate electrode
G1, a first semiconductor pattern C1, a first source electrode S1
and a first drain electrode D1.
[0046] The first gate electrode G1 is electrically connected to the
gate electrode portion GE protruded from the gate bus line GBL.
[0047] The first semiconductor pattern C1 is disposed over the
first gate electrode such that the first semiconductor pattern C1
is electrically insulated from the first gate electrode G1. That
is, a gate insulation layer (not shown) including a dielectric
material is interposed between the semiconductor pattern C1 and the
first gate electrode G1.
[0048] The first drain electrode D1 formed on the first
semiconductor pattern C1 is electrically connected to the drain
electrode portion DE protruded from the data bus line DBL.
[0049] The first source electrode S1 is spaced apart from the first
drain electrode D1 and electrically connected to the first
semiconductor pattern C1.
[0050] The driver device TFT2 is also disposed in the pixel region.
The driver device TFT2 includes a second gate electrode G2, a
second semiconductor pattern C2, a second drain electrode D2 and a
second source electrode S2.
[0051] The second gate electrode G2 is electrically connected to
the first source electrode S1 of the switching device TFT1.
[0052] The second semiconductor pattern C2 is disposed over the
second gate electrode G2 such that the second semiconductor pattern
C2 is electrically insulated from the second gate electrode G2.
That is, the gate insulation layer (not shown) is interposed
between the second gate electrode G2 and the second semiconductor
pattern C2.
[0053] The second drain electrode D2 formed on the second
semiconductor pattern C2 is electrically connected to the power
supplying line PSL.
[0054] The second source electrode S2 formed on the second
semiconductor pattern C2 is spaced apart from the second drain
electrode D2 and electrically connected to the light-emitting unit
200.
[0055] The storage capacitor C.sub.st includes a first capacitor
electrode C.sub.st1, a second capacitor electrode C.sub.st2 and a
dielectric layer. The first capacitor electrode C.sub.st1 is
electrically connected to the second gate electrode G2.
Alternatively, a portion of the second gate electrode G2 may
function as the first capacitor electrode C.sub.st1. The second
capacitor electrode C.sub.st2 is electrically connected to the
power supplying line PSL. Alternatively, a portion of the power
supplying line PSL may function as the second capacitor electrode
C.sub.st2. The dielectric layer is interposed between the first and
second capacitor electrodes C.sub.st1 and C.sub.st2. The driver
device TFT2 may be kept in a turned-on state during one frame
period due to the storage capacitor C.sub.st.
[0056] When an image signal and a turn-on voltage are applied to
the data bus line DBL and the gate bus line GBL, respectively, the
image signal is applied to the first source electrode S1 of the
switching device TFT1 through the first drain electrode D1 and the
first semiconductor pattern C1 of the switching device TFT1.
[0057] Then, the image signal outputted from the first source
electrode S1 of the switching device TFT1 is applied to the second
gate electrode G2 of the driver device TFT2 to turn on the driver
device TFT2. A voltage level of the image signal determines a
resistance of the second semiconductor pattern C2. When the driver
device TFT2 is turned on, the voltage Vdd of the power supplying
line PSL is applied to the second source electrode S2 of the driver
device TFT2 through the second drain electrode D2 and the second
semiconductor pattern C2. The voltage Vdd is ejected in accordance
with the resistance of the second semiconductor pattern C2 to
output a first driving signal corresponding to the voltage level of
the image signal.
[0058] FIG. 2 is a flow chart showing a method of manufacturing a
display apparatus in accordance with an exemplary embodiment of the
present invention. FIG. 3 is a plan view showing first electrodes
formed on a base substrate in accordance with an exemplary
embodiment of the present invention. FIG. 4 is a cross-sectional
view taken along a line I-I' of FIG. 3.
[0059] Referring to FIGS. 2 to 4, the switching device TFT1 of FIG.
1, the driver device TFT2 of FIG. 1, the data bus line DBL of FIG.
1, the gate bus line GBL of FIG. 1 and the power supply line PSL of
FIG. 1 are formed on a pixel area PA of a base substrate 100 (step
S50). First electrodes 120 are formed on the pixel area PA of a
base substrate 100 having the switching device TFT1 of FIG. 1, the
driver device TFT2 of FIG. 1, the data bus line DBL of FIG. 1, the
gate bus line GBL of FIG. 1 and the power supply line PSL of FIG. 1
(step S100). A peripheral region PR surrounds the pixel area
PA.
[0060] A transparent conductive material such as indium tin oxide
(ITO), tin oxide (TO), indium zinc oxide (IZO), zinc oxide (ZO),
etc., or a reflective material such as aluminum alloy, silver,
silver alloy, etc., is deposited on the base substrate 100 through
a sputtering method, a chemical vapor deposition (CVD), etc.
[0061] The deposited material is patterned through a
photolithography process having an exposing process, a development
process, an etching process, etc., to form the first electrodes
120.
[0062] The first electrodes 120 are arranged in a matrix shape in
the pixel area PA. In this exemplary embodiment, the matrix shape
of the first electrodes 120 has 3n columns and m rows, and the
number of the first electrodes 120 is 3n.times.m. The first
electrodes 120 correspond to red pixels, green pixels and blue
pixels, respectively. The red pixels correspond to red light
emitting patterns of R1, R2, . . . Rn columns. The green pixels
correspond to green light emitting patterns of G1, G2, . . . Gn
columns. The blue pixels correspond to blue light emitting patterns
of B1, B2, . . . Bn columns. In this exemplary embodiment, the red
light emitting patterns of R1, R2, . . . Rn columns have first
light emitting patterns 141 of R1, R4 . . . Rn-2 columns, second
light emitting patterns 142 of R2, R5, . . . Rn-1 columns and third
light emitting patterns 142a of R3, R6, . . . Rn columns. The green
light emitting patterns of G1, G2, . . . Gn columns may have first
green light emitting patterns of G1, G4, . . . Gn-2 columns, second
green light emitting patterns of G2, G5, . . . Gn-1 columns and
third green light emitting patterns of G3, G6, . . . Gn columns.
The blue light emitting patterns of B1, B2, . . . Bn columns may
have first blue light emitting patterns of B1, B4, . . . Bn-2
columns, second blue light emitting patterns of B2, B5, . . . Bn-1
columns and third blue light emitting patterns of B3, B6, . . . Bn
columns.
[0063] FIG. 5 is a cross-sectional view showing a bank formed
between the first electrodes of FIG. 3.
[0064] Referring to FIGS. 2 and 5, a bank 130 is formed on the base
substrate 100 on which the first electrodes 120 are formed (step
S200).
[0065] An organic layer (not shown) is formed on the base substrate
100 through a spin coating method or a slit coating method. In this
exemplary the organic layer (not shown) has photoresist. When the
organic layer (not shown) has the photoresist, the bank 130 is
formed through the photo process. Alternatively, the organic layer
(not shown) may not have the photoresist. When the organic layer
(not shown) does not have the photoresist, the bank 130 is formed
through the photolithography process that includes the etching
process.
[0066] The organic layer (not shown) is patterned as the matrix
shape to form cavities 130a on the first electrodes 120. The bank
130 is disposed between the first electrodes 120 so that the first
electrodes 120 are electrically insulated from each another.
[0067] FIG. 6 is a plan view showing first light emitting patterns
formed on the base substrate of FIG. 5. FIG. 7 is a cross-sectional
view taken along a line II-II' of FIG. 6.
[0068] Referring to FIGS. 2, 6 and 7, the first light emitting
patterns 141 are formed on a portion of the first electrodes 120
(step S300). The first light emitting patterns 141 are formed using
a light emitting material ejecting device (not shown) having a
plurality of nozzles arranged substantially in parallel. Droplets
of light emitting material are ejected on the first electrodes 120
through the nozzles.
[0069] When size and resolution of the display apparatus increase,
the number of the nozzles is smaller than the number of the first
electrodes 120 of unit row of the matrix shape. Therefore, the
droplets are ejected on the first electrodes 120 through a
plurality of scanning processes so that the droplets are ejected on
all of the first electrodes 120. Each of the scanning processes
includes a plurality of jetting the droplets through the nozzles.
That is, each of the scanning processes having the jetting
processes is repeated to fill all of the cavities 130a with the
droplets. The number of the jetting processes of each of the
scanning processes may be the number of the first electrodes 120 of
unit column of the matrix shape. Alternatively, the number of the
jetting processes of each of the scanning processes may also be a
summation of the number of the first electrodes 120 of the unit
column and the number of dummy light emitting patterns 144 shown in
FIG. 12 corresponding to the unit column.
[0070] When a distance between the droplets is small, evaporation
rate of volatile materials in the droplets is affected by an
adjacent droplet so that the first light emitting patterns 141 may
not have uniform thickness. Therefore, the nozzles are spaced apart
from one another by a distance of more than an interval between
three first electrodes that are adjacent to one another so that the
evaporation rate of the volatile materials in the droplets is not
affected by the adjacent droplet. That is, the droplets are ejected
on once in every at least two first electrodes. In this exemplary
embodiment, the droplets are ejected on once in every nine first
electrodes. That is, the droplets are ejected on once in every
three red pixels.
[0071] For example, the light emitting material ejecting device
(not shown) has two nozzles, and the droplets are ejected on the
first electrodes 120 of the R1 column and the R4 column. The light
emitting material ejecting device (not shown) then drops the
droplets on the first electrodes 120 of the R7 column and the R10
column. The light emitting material ejecting device (not shown)
then drops the droplets on the first electrodes 120 of the R13
column and the R16 column.
[0072] The ejecting process is repeated until the droplets are
ejected on the first electrodes 120 of the Rn-2 column. That is,
the light emitting material ejecting device (not shown) drops the
droplets on the first electrodes 120 corresponding to once in every
three red pixels so that the first light emitting patterns 141 are
formed on the first electrodes 120 corresponding to once in every
three red pixels. Therefore, the evaporation rates of the volatile
materials in the droplets of the first light emitting patterns 141
are substantially equal to one another so that the first light
emitting patterns 141 have uniform profile and thickness.
Alternatively, the first light emitting patterns may be formed on
the first electrodes 120 corresponding to once in every two to
thirty columns. The volatile materials in the droplets of the R1,
R4, . . . Rn-2 columns are dried to form the first light emitting
patterns 141.
[0073] FIG. 8 is a plan view showing second light emitting patterns
formed on the base substrate of FIG. 6. FIG. 9 is a cross-sectional
view taken along a line III-III' of FIG. 8.
[0074] Referring to FIGS. 2, 8 and 9, the second light emitting
patterns 142 are formed on a portion of the first electrodes 120
between the first light emitting patterns (step S400). The second
light emitting patterns 142 are formed using the light emitting
material ejecting device (not shown) having the nozzles arranged
substantially in parallel. The droplets of the light emitting
material are ejected on the first electrodes 120 through the
nozzles.
[0075] In this exemplary embodiment, the droplets are ejected on
the first electrodes 120 of the R2 column that is between the R1
and R4 columns, and the R5 column that is between the R4 and R7
columns. The light emitting material ejecting device (not shown)
then drops the droplets on the first electrodes 120 of the R8
column and the R11 column. The light emitting material ejecting
device (not shown) then drops the droplets on the first electrodes
120 of the R14 column and the R17 column.
[0076] The ejecting process is repeated until the droplets are
ejected on the first electrodes 120 of the Rn-1 column. That is,
the light emitting material ejecting device (not shown) drops the
droplets on the first electrodes 120 corresponding to once in every
three red pixels so that the second light emitting patterns 142 are
formed on the first electrodes 120 corresponding to once in every
three red pixels. Therefore, the evaporation rates of the volatile
materials in the droplets of the second light emitting patterns 142
are substantially equal to one another so that the second light
emitting patterns 142 have uniform profile and thickness.
Alternatively, the first light emitting patterns may be formed on
the first electrodes 120 corresponding to once in every two to
thirty columns. The volatile materials in the droplets of the R2,
R5, Rn-1 columns are dried to form the second light emitting
patterns 142.
[0077] FIG. 10 is a plan view showing third light emitting patterns
formed on the base substrate of FIG. 8. FIG. 11 is a
cross-sectional view taken along a line IV-IV' of FIG. 10.
[0078] Referring to FIGS. 2, 10 and 11, the light emitting material
ejecting device (not shown) checks whether the droplets are ejected
on all of the first electrodes 120 or not (step S500).
[0079] When the droplets are not ejected on all of the first
electrodes 120, the third light emitting patterns 142a are formed
on a portion of the first electrodes 120 between the first light
emitting patterns. The third light emitting patterns 142a are
formed using the light emitting material ejecting device (not
shown) having the nozzles arranged substantially in parallel. The
droplets of the light emitting material are ejected on the first
electrodes 120 through the nozzles.
[0080] In this exemplary embodiment, the droplets are ejected on
the first electrodes 120 of the R3 column that is between the R2
and R4 columns, and the R6 column that is between the R5 and R7
columns. The light emitting material ejecting device (not shown)
then drops the droplets on the first electrodes 120 of the R9
column and the R12 column. The light emitting material ejecting
device (not shown) then drops the droplets on the first electrodes
120 of the R15 column and the R18 column.
[0081] The ejecting process is repeated until the droplets are
ejected on the first electrodes 120 of the Rn column. That is, the
light emitting material ejecting device (not shown) drops the
droplets on the first electrodes 120 corresponding to once in every
three red pixels so that the third light emitting patterns 142a are
formed on the first electrodes 120 corresponding to once in every
three red pixels. Therefore, the evaporation rates of the volatile
materials in the droplets of the third light emitting patterns 142a
are substantially equal to one another so that the third light
emitting patterns 142a have uniform profile and thickness. The
volatile materials in the droplets of the R3, R6, . . . Rn columns
are dried to form the third light emitting patterns 142a.
[0082] Positive charge carrier injection patterns (not shown) may
be formed between the first electrodes 120 and the first to third
light emitting patterns 141, 142 and 142a. The positive charge
carrier injection patterns (not shown) are formed through the same
method as the first to third light emitting patterns 141, 142 and
142a.
[0083] FIG. 12 is a plan view showing green light emitting patterns
and blue light emitting patterns formed on the base substrate of
FIG. 10.
[0084] Referring to FIG. 12, the light emitting patterns that
corresponds to the R1, G1, B1, R2, G2, B2, . . . Rn, Gn and Bn
columns have the red light emitting patterns 141, 142 and 142a that
each corresponds to the R1, R2, . . . Rn columns, the green light
emitting patterns that each corresponds to the G1, G2, . . . Gn
columns and the blue light emitting patterns that each corresponds
to the B1, B2, . . . Bn columns.
[0085] After the red light emitting patterns 141, 142 and 142a are
completed, the green light emitting patterns and the blue light
emitting patterns are formed through the same method as the red
light emitting patterns 141, 142 and 142a.
[0086] The green light emitting patterns or the blue light emitting
patterns may be formed on the first electrodes 120 corresponding to
once in every two to thirty columns. Prior to forming the light
emitting patterns, the positive charge carrier injection patterns
(not shown) may be formed between the first electrodes 120 and the
light emitting patterns through the same method as the light
emitting patterns.
[0087] In this exemplary embodiment, prior to forming the light
emitting patterns, dummy light emitting patterns 144 are formed in
the peripheral region PR so that the evaporation rate of the light
emitting patterns adjacent to an interface between the pixel area
PA and the peripheral region PR becomes substantially equal to one
another to uniformize the thickness of the light emitting
patterns.
[0088] FIG. 13 is a cross-sectional view showing a second electrode
formed on the base substrate of FIG. 12.
[0089] Referring to FIGS. 2 and 13, a conductive material is
deposited on the base substrate 100 including the red light
emitting patterns that has the first to third light emitting
patterns 141, 142 and 142a, the green light emitting patterns and
the blue light emitting patterns to form a second electrode 150.
The second electrode 150 comprises an alkaline metal such as
lithium (Li), sodium (Na), etc., an alkaline earth metal such as
magnesium (Mg), calcium (Ca), barium (Ba), etc. The second
electrode 150 may have a double-layered structure of the metal
layer and a capping layer formed on the metal layer. The second
electrode 150 may be formed through the sputtering method, the CVD
method, etc.
[0090] In this exemplary embodiment, the first to third light
emitting patterns 141, 142 and 142a are formed on the first
electrodes 120 of the R1, R4, . . . Rn-2 columns, the R2, R5, . . .
Rn-1 columns and the R3, R6, . . . Rn columns, respectively.
Alternatively, the light emitting patterns may be grouped based on
each of the columns R1, R2, . . . Rn. For example, the first
electrodes of the R1, R4 and R2 columns may be the first to third
light emitting patterns, respectively. For example when n is 9, the
first electrodes of the R1, R4, R7, R2, R5, R8, R3, R6 and R9
columns are the first to ninth light emitting patterns,
respectively. In addition, the light emitting patterns of the R1,
R2, . . . Rn columns may be formed in a random order.
[0091] In this exemplary embodiment, the light emitting patterns
are formed through the scanning processes in the column direction.
Alternatively, the light emitting patterns may be formed through
the scanning processes in the row direction.
[0092] According to the present invention, scanning order of
droplets of light emitting material is controlled so that
evaporation rates of the droplets are not affected by adjacent
droplets. Therefore, thicknesses of light emitting patterns formed
by the droplets are uniformized so that luminance of a display
apparatus is improved, and also uniformized.
[0093] This invention has been described with reference to the
exemplary embodiments. It is evident, however, that many
alternative modifications and variations will be apparent to those
having skill in the art in light of the foregoing description.
Accordingly, the present invention embraces all such alternative
modifications and variations as fall within the spirit and scope of
the appended claims.
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