U.S. patent application number 10/965453 was filed with the patent office on 2005-06-02 for hermetically sealed glass package and method of fabrication.
Invention is credited to Aitken, Bruce G., Danielson, Paul S., Dickinson, James E. JR., Logunov, Stephan L., Morena, Robert, Powley, Mark L., Reddy, Kamjula P., Schroeder, Joseph F. III, Streltsov, Alexander.
Application Number | 20050116245 10/965453 |
Document ID | / |
Family ID | 36203390 |
Filed Date | 2005-06-02 |
United States Patent
Application |
20050116245 |
Kind Code |
A1 |
Aitken, Bruce G. ; et
al. |
June 2, 2005 |
Hermetically sealed glass package and method of fabrication
Abstract
A hermetically sealed glass package and method for manufacturing
the hermetically sealed glass package are described herein using an
OLED display as an example. In one embodiment, the hermetically
sealed glass package is manufactured by providing a first substrate
plate and a second substrate plate. The second substrate contains
at least one transition or rare earth metal such as iron, copper,
vanadium, manganese, cobalt, nickel, chromium, neodymium and/or
cerium. A sensitive thin-film device that needs protection is
deposited onto the first substrate plate. A laser is then used to
heat the doped second substrate plate in a manner that causes a
portion of it to swell and form a hermetic seal that connects the
first substrate plate to the second substrate plate and also
protects the thin film device. The second substrate plate is doped
with at least one transition metal such that when the laser
interacts with it there is an absorption of light from the laser in
the second substrate plate, which leads to the formation of the
hermetic seal while avoiding thermal damage to the thin-film
device. Another embodiment of the hermetically sealed glass package
and a method for manufacturing that hermetically sealed glass
package are also described herein.
Inventors: |
Aitken, Bruce G.; (Corning,
NY) ; Danielson, Paul S.; (Corning, NY) ;
Dickinson, James E. JR.; (Corning, NY) ; Logunov,
Stephan L.; (Corning, NY) ; Morena, Robert;
(Lindley, NY) ; Powley, Mark L.; (Campbell,
NY) ; Reddy, Kamjula P.; (Corning, NY) ;
Schroeder, Joseph F. III; (Corning, NY) ; Streltsov,
Alexander; (Chandler, AZ) |
Correspondence
Address: |
CORNING INCORPORATED
SP-TI-3-1
CORNING
NY
14831
|
Family ID: |
36203390 |
Appl. No.: |
10/965453 |
Filed: |
October 13, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10965453 |
Oct 13, 2004 |
|
|
|
10414653 |
Apr 16, 2003 |
|
|
|
Current U.S.
Class: |
257/99 ; 257/100;
438/25 |
Current CPC
Class: |
C03C 27/06 20130101;
C03C 3/108 20130101; C03B 23/245 20130101; C03C 3/091 20130101;
C03C 3/093 20130101; C03C 8/24 20130101; H01L 51/5246 20130101;
C03C 8/10 20130101; H01L 51/524 20130101; C03C 8/04 20130101 |
Class at
Publication: |
257/099 ;
257/100; 438/025 |
International
Class: |
H01L 021/00; H01L
033/00 |
Claims
What is claimed is:
1. A glass package comprising: a glass plate; and a sealing glass
plate doped with at least one transition or rare earth metal,
wherein said doped sealing glass plate includes a swelled portion
that is a hermetic seal which connects said glass plate to said
doped sealing glass plate and also creates a gap between said glass
plate and said doped sealing glass plate.
2. The glass package of claim 1, wherein said doped sealing glass
plate has a composition designed to be heated by an infrared
wavelength laser.
3. The glass package of claim 2, wherein said composition is a
follows:
13 Fe.sub.2O.sub.3 0.0-5 (mole %) V.sub.2O.sub.5 0.0-4 (mole %)
TiO.sub.2 0.0-5 (mole %) CuO 0.0-10 (mole %) NiO 0.0-3 (mole %)
B.sub.2O.sub.3 8-30 (mole %) Al.sub.2O.sub.3 1.2-12 (mole %)
Li.sub.2O 0-2 (mole %) Na.sub.2O 0-6 (mole %) K.sub.2O 0-3 (mole %)
MO 0-3 (mole %) (M = Mg, Ca, Sr, Ba, Zn) Other 0-3 (mole %)
SiO.sub.2 balance.
4. The glass package of claim 1, wherein said doped sealing glass
plate has a composition designed to be heated by a visible
wavelength laser.
5. The glass package of claim 4, wherein said composition is a
follows:
14 Co.sub.3O.sub.4 0.5-3 (mole %) B.sub.2O.sub.3 8-30 (mole %)
Al.sub.2O 1.2-12 (mole %) Li.sub.2O 0-2 (mole %) Na.sub.2O 0-6
(mole %) K.sub.2O 0-3 (mole %) MO 0-3 (mole %) (M = Mg, Ca, Sr, Ba,
Zn) Other 0-3 (mole %) SiO.sub.2 balance.
6. The glass package of claim 1, wherein said doped sealing glass
plate has a composition designed to be heated by an ultraviolet
wavelength laser.
7. The glass package of claim 6, wherein said composition is a
follows:
15 CeO.sub.2 1-4 (mole %) TiO.sub.2 0.0-3 (mole %) B.sub.2O.sub.3
8-30 (mole %) Al.sub.2O.sub.3 1.2-12 (mole %) Li.sub.2O 0-2 (mole
%) Na.sub.2O 0-6 (mole %) K.sub.2O 0-3 (mole %) MO 0-3 (mole %) (M
= Mg, Ca, Sr, Ba, Zn) Other 0-3 (mole %) SiO.sub.2 balance.
8. The glass package of claim 6, wherein said composition is a
follows:
16 Al.sub.2O 0-15 (mole %) B.sub.2O.sub.3 10-30 (mole %) Li.sub.2O
0-3 (mole %) Na.sub.2O 3-8 (mole %) K.sub.2O 0-4 (mole %) CuO 0.2-1
(mole %) SnO 0.1-1 (mole %) Br 0.2-1 (mole %) Cl 0-2 (mole %) F 0-6
(mole %) CeO.sub.2 0-3 (mole %) SiO.sub.2 balance.
9. The glass package of claim 1, wherein said doped sealing glass
plate is a laminated glass plate with a clear glass layer and an
absorbing glass layer.
10. The glass package of claim 1, wherein said doped sealing glass
plate is made from a multi-component glass doped with at least one
transition or rare earth metal such as iron, copper, vanadium,
manganese, cobalt, nickel, chromium, neodymium or cerium.
11. A glass package comprising: a first glass plate; a second glass
plate; and a sealing glass fiber doped with at least one transition
or rare earth metal, wherein said doped sealing glass fiber is
heated in a manner that causes said doped sealing glass fiber to
soften and form a hermetic seal which connects said first glass
plate to said second glass plate.
12. The glass package of claim 11, wherein said doped sealing glass
fiber has a composition designed to be heated by an infrared
wavelength laser.
13. The glass package of claim 12, wherein said composition is a
follows:
17 Fe.sub.2O.sub.3 0.0-5 (mole %) V.sub.2O.sub.5 0.0-4 (mole %)
TiO.sub.2 0.0-5 (mole %) CuO 0.0-10 (mole %) NiO 0.0-3 (mole %)
B.sub.2O.sub.3 8-30 (mole %) Al.sub.2O.sub.3 1.2-12 (mole %)
Li.sub.2O 0-2 (mole %) Na.sub.2O 0-6 (mole %) K.sub.2O 0-3 (mole %)
MO 0-3 (mole %) (M = Mg, Ca, Sr, Ba, Zn) Other 0-3 (mole %)
SiO.sub.2 balance.
14. The glass package of claim 1, wherein said doped sealing glass
fiber has a composition designed to be heated by a visible
wavelength laser.
15. The glass package of claim 14, wherein said composition is a
follows:
18 Co.sub.3O.sub.4 0.5-3 (mole %) B.sub.2O.sub.3 8-30 (mole %)
Al.sub.2O 1.2-12 (mole %) Li.sub.2O 0-2 (mole %) Na.sub.2O 0-6
(mole %) K.sub.2O 0-3 (mole %) MO 0-3 (mole %) (M = Mg, Ca, Sr, Ba,
Zn) Other 0-3 (mole %) SiO.sub.2 balance.
16. The glass package of claim 11, wherein said doped sealing glass
fiber has a composition designed to be heated by an ultraviolet
wavelength laser.
17. The glass package of claim 16, wherein said composition is a
follows:
19 CeO.sub.2 1-4 (mole %) TiO.sub.2 0.0-3 (mole %) B.sub.2O.sub.3
8-30 (mole %) Al.sub.2O.sub.3 1.2-12 (mole %) Li.sub.2O 0-2 (mole
%) Na.sub.2O 0-6 (mole %) K.sub.2O 0-3 (mole %) MO 0-3 (mole %) (M
= Mg, Ca, Sr, Ba, Zn) Other 0-3 (mole %) SiO.sub.2 balance.
18. The glass package of claim 16, wherein said composition is a
follows:
20 Al.sub.2O 0-15 (mole %) B.sub.2O.sub.3 10-30 (mole %) Li.sub.2O
0-3 (mole %) Na.sub.2O 3-8 (mole %) K.sub.2O 0-4 (mole %) CuO 0.2-1
(mole %) SnO 0.1-1 (mole %) Br 0.2-1 (mole %) Cl 0-2 (mole %) F 0-6
(mole %) CeO.sub.2 0-3 (mole %) SiO.sub.2 balance.
19. The glass package of claim 11, wherein said doped sealing glass
fiber is made from a multi-component glass doped with at least one
transition or rare earth metal such as iron, copper, vanadium,
manganese, cobalt, nickel, chromium, neodymium or cerium.
20. An organic light emitting diode display, comprising: a
substrate plate; at least one organic light emitting diode; and a
sealing glass plate doped with at least one transition or rare
earth metal, wherein said doped sealing glass plate includes a
swelled portion that is a hermetic seal which connects said
substrate plate to said doped sealing glass plate and also creates
a gap to make room for said at least one organic light emitting
diode to be located between said substrate plate and said doped
sealing glass plate and further protects said at least one organic
light emitting diode located between said substrate plate and said
doped sealing glass plate.
21. The organic light emitting diode display of claim 20, wherein
said doped sealing glass plate has a composition designed to be
heated by an infrared wavelength laser.
22. The organic light emitting diode display of claim 21, wherein
said composition is a follows:
21 Fe.sub.2O.sub.3 0.0-5 (mole %) V.sub.2O.sub.5 0.0-4 (mole %)
TiO.sub.2 0.0-5 (mole %) CuO 0.0-10 (mole %) NiO 0.0-3 (mole %)
B.sub.2O.sub.3 8-30 (mole %) Al.sub.2O.sub.3 1.2-12 (mole %)
Li.sub.2O 0-2 (mole %) Na.sub.2O 0-6 (mole %) K.sub.2O 0-3 (mole %)
MO 0-3 (mole %) (M = Mg, Ca, Sr, Ba, Zn) Other 0-3 (mole %)
SiO.sub.2 balance.
23. The organic light emitting diode display of claim 20, wherein
said doped sealing glass plate has a composition designed to be
heated by a visible wavelength laser.
24. The organic light emitting diode display of claim 23, wherein
said composition is a follows:
22 Co.sub.3O.sub.4 0.5-3 (mole %) B.sub.2O.sub.3 8-30 (mole %)
Al.sub.2O 1.2-12 (mole %) Li.sub.2O 0-2 (mole %) Na.sub.2O 0-6
(mole %) K.sub.2O 0-3 (mole %) MO 0-3 (mole %) (M = Mg, Ca, Sr, Ba,
Zn) Other 0-3 (mole %) SiO.sub.2 balance.
25. The organic light emitting diode display of claim 20, wherein
said doped sealing glass plate has a composition designed to be
heated by an ultraviolet wavelength laser.
26. The organic light emitting diode display of claim 25, wherein
said composition is a follows:
23 CeO.sub.2 1-4 (mole %) TiO.sub.2 0.0-3 (mole %) B.sub.2O.sub.3
8-30 (mole %) Al.sub.2O.sub.3 1.2-12 (mole %) Li.sub.2O 0-2 (mole
%) Na.sub.2O 0-6 (mole %) K.sub.2O 0-3 (mole %) MO 0-3 (mole %) (M
= Mg, Ca, Sr, Ba, Zn) Other 0-3 (mole %) SiO.sub.2 balance.
27. The organic light emitting diode display of claim 25, wherein
said composition is a follows:
24 Al.sub.2O 0-15 (mole %) B.sub.2O.sub.3 10-30 (mole %) Li.sub.2O
0-3 (mole %) Na.sub.2O 3-8 (mole %) K.sub.2O 0-4 (mole %) CuO 0.2-1
(mole %) SnO 0.1-1 (mole %) Br 0.2-1 (mole %) Cl 0-2 (mole %) F 0-6
(mole %) CeO.sub.2 0-3 (mole %) SiO.sub.2 balance.
28. The organic light emitting diode display of claim 20, wherein
said doped sealing glass plate is a laminated glass plate with a
clear glass layer and an absorbing glass layer.
29. The organic light emitting diode display of claim 20, wherein
said doped sealing glass plate is made from a multi-component glass
doped with at least one transition or rare earth metal such as
iron, copper, vanadium, manganese, cobalt, nickel, chromium,
neodymium or cerium.
30. An organic light emitting diode display, comprising: a first
substrate plate; at least one organic light emitting diode; a
second substrate plate; and a sealing glass fiber doped with at
least one transition or rare earth metal, wherein said doped
sealing glass fiber was heated in a manner that caused said doped
sealing glass fiber to soften and form a hermetic seal which
connects said first substrate plate to said second substrate plate
and also protects said at least one organic light emitting diode
located between said first substrate plate and said second
substrate plate.
31. The organic light emitting diode display of claim 30, wherein
said doped sealing glass fiber has a composition designed to be
heated by an infrared wavelength laser.
32. The organic light emitting diode display of claim 31, wherein
said composition is a follows:
25 Fe.sub.2O.sub.3 0.0-5 (mole %) V.sub.2O.sub.5 0.0-4 (mole %)
TiO.sub.2 0.0-5 (mole %) CuO 0.0-10 (mole %) NiO 0.0-3 (mole %)
B.sub.2O.sub.3 8-30 (mole %) Al.sub.2O.sub.3 1.2-12 (mole %)
Li.sub.2O 0-2 (mole %) Na.sub.2O 0-6 (mole %) K.sub.2O 0-3 (mole %)
MO 0-3 (mole %) (M = Mg, Ca, Sr, Ba, Zn) Other 0-3 (mole %)
SiO.sub.2 balance.
33. The organic light emitting diode display of claim 30, wherein
said doped sealing glass fiber has a composition designed to be
heated by a visible wavelength laser.
34. The organic light emitting diode display of claim 33, wherein
said composition is a follows:
26 Co.sub.3O.sub.4 0.5-3 (mole %) B.sub.2O.sub.3 8-30 (mole %)
Al.sub.2O 1.2-12 (mole %) Li.sub.2O 0-2 (mole %) Na.sub.2O 0-6
(mole %) K.sub.2O 0-3 (mole %) MO 0-3 (mole %) (M = Mg, Ca, Sr, Ba,
Zn) Other 0-3 (mole %) SiO.sub.2 balance.
35. The organic light emitting diode display of claim 30, wherein
said doped sealing glass fiber has a composition designed to be
heated by an ultraviolet wavelength laser.
36. The organic light emitting diode display of claim 35, wherein
said composition is a follows:
27 CeO.sub.2 1-4 (mole %) TiO.sub.2 0.0-3 (mole %) B.sub.2O.sub.3
8-30 (mole %) Al.sub.2O.sub.3 1.2-12 (mole %) Li.sub.2O 0-2 (mole
%) Na.sub.2O 0-6 (mole %) K.sub.2O 0-3 (mole %) MO 0-3 (mole %) (M
= Mg, Ca, Sr, Ba, Zn) Other 0-3 (mole %) SiO.sub.2 balance.
37. The organic light emitting diode display of claim 35, wherein
said composition is a follows:
28 Al.sub.2O 0-15 (mole %) B.sub.2O.sub.3 10-30 (mole %) Li.sub.2O
0-3 (mole %) Na.sub.2O 3-8 (mole %) K.sub.2O 0-4 (mole %) CuO 0.2-1
(mole %) SnO 0.1-1 (mole %) Br 0.2-1 (mole %) Cl 0-2 (mole %) F 0-6
(mole %) CeO.sub.2 0-3 (mole %) SiO.sub.2 balance.
38. The organic light emitting diode display of claim 30, wherein
said doped sealing glass fiber is made from a multi-component glass
doped with at least one transition or rare earth metal such as
iron, copper, vanadium, manganese, cobalt, nickel, chromium,
neodymium or cerium.
39. A doped sealing glass plate which includes at least one
transition or rare earth metal and also includes a swelled portion
which forms a hermetic seal that connects said doped glass plate to
a glass plate and also creates a gap between said doped glass plate
and said glass plate.
40. The doped sealing glass plate of claim 39, wherein said doped
sealing glass plate has a composition which can be heated by an
infrared wavelength laser.
41. The doped sealing glass plate of claim 40, wherein said
composition is a follows:
29 Fe.sub.2O.sub.3 0.0-5 (mole %) V.sub.2O.sub.5 0.0-4 (mole %)
TiO.sub.2 0.0-5 (mole %) CuO 0.0-10 (mole %) NiO 0.0-3 (mole %)
B.sub.2O.sub.3 8-30 (mole %) Al.sub.2O.sub.3 1.2-12 (mole %)
Li.sub.2O 0-2 (mole %) Na.sub.2O 0-6 (mole %) K.sub.2O 0-3 (mole %)
MO 0-3 (mole %) (M = Mg, Ca, Sr, Ba, Zn) Other 0-3 (mole %)
SiO.sub.2 balance.
42. The doped sealing glass plate of claim 39, wherein said doped
sealing glass plate has a composition which can be heated by a
visible wavelength laser.
43. The doped sealing glass plate of claim 42, wherein said
composition is a follows:
30 Co.sub.3O.sub.4 0.5-3 (mole %) B.sub.2O.sub.3 8-30 (mole %)
Al.sub.2O 1.2-12 (mole %) Li.sub.2O 0-2 (mole %) Na.sub.2O 0-6
(mole %) K.sub.2O 0-3 (mole %) MO 0-3 (mole %) (M = Mg, Ca, Sr, Ba,
Zn) Other 0-3 (mole %) SiO.sub.2 balance.
44. The doped sealing glass plate of claim 39, wherein said doped
sealing glass plate has a composition which can be heated by an
ultraviolet wavelength laser.
45. The doped sealing glass plate of claim 44, wherein said
composition is a follows:
31 CeO.sub.2 1-4 (mole %) TiO.sub.2 0.0-3 (mole %) B.sub.2O.sub.3
8-30 (mole %) Al.sub.2O.sub.3 1.2-12 (mole %) Li.sub.2O 0-2 (mole
%) Na.sub.2O 0-6 (mole %) K.sub.2O 0-3 (mole %) MO 0-3 (mole %) (M
= Mg, Ca, Sr, Ba, Zn) Other 0-3 (mole %) SiO.sub.2 balance.
46. The doped sealing glass plate of claim 44, wherein said
composition is a follows:
32 Al.sub.2O 0-15 (mole %) B.sub.2O.sub.3 10-30 (mole %) Li.sub.2O
0-3 (mole %) Na.sub.2O 3-8 (mole %) K.sub.2O 0-4 (mole %) CuO 0.2-1
(mole %) SnO 0.1-1 (mole %) Br 0.2-1 (mole %) Cl 0-2 (mole %) F 0-6
(mole %) CeO.sub.2 0-3 (mole %) SiO.sub.2 balance.
47. The doped sealing glass plate of claim 39, wherein said doped
sealing glass plate is a laminated glass plate with a clear glass
layer and an absorbing glass layer.
48. The doped sealing glass plate of claim 39, wherein said doped
sealing glass plate is made from a multi-component glass doped with
at least one transition or rare earth metal such as iron, copper,
vanadium, manganese, cobalt, nickel, chromium, neodymium or
cerium.
49. A doped sealing glass fiber which includes at least one
transition or rare earth metal and which is heated in a manner that
causes said doped sealing glass fiber to soften and form a hermetic
seal which connects a first glass plate to a second glass
plate.
50. The doped sealing glass fiber of claim 49, wherein said doped
sealing glass fiber has a composition which can be heated by an
infrared wavelength laser.
51. The doped sealing glass fiber of claim 50, wherein said
composition is a follows:
33 Fe.sub.2O.sub.3 0.0-5 (mole %) V.sub.2O.sub.5 0.0-4 (mole %)
TiO.sub.2 0.0-5 (mole %) CuO 0.0-10 (mole %) NiO 0.0-3 (mole %)
B.sub.2O.sub.3 8-30 (mole %) Al.sub.2O.sub.3 1.2-12 (mole %)
Li.sub.2O 0-2 (mole %) Na.sub.2O 0-6 (mole %) K.sub.2O 0-3 (mole %)
MO 0-3 (mole %) (M = Mg, Ca, Sr, Ba, Zn) Other 0-3 (mole %)
SiO.sub.2 balance.
52. The doped sealing glass fiber of claim 49, wherein said doped
sealing glass fiber has a composition which can be heated by a
visible wavelength laser.
53. The doped sealing glass fiber of claim 52, wherein said
composition is a follows:
34 Co.sub.3O.sub.4 0.5-3 (mole %) B.sub.2O.sub.3 8-30 (mole %)
Al.sub.2O 1.2-12 (mole %) Li.sub.2O 0-2 (mole %) Na.sub.2O 0-6
(mole %) K.sub.2O 0-3 (mole %) MO 0-3 (mole %) (M = Mg, Ca, Sr, Ba,
Zn) Other 0-3 (mole %) SiO.sub.2 balance.
54. The doped sealing glass fiber of claim 49, wherein said doped
sealing glass fiber has a composition which can be heated by an
ultraviolet wavelength laser.
55. The doped sealing glass fiber of claim 54, wherein said
composition is a follows:
35 CeO.sub.2 1-4 (mole %) TiO.sub.2 0.0-3 (mole %) B.sub.2O.sub.3
8-30 (mole %) Al.sub.2O.sub.3 1.2-12 (mole %) Li.sub.2O 0-2 (mole
%) Na.sub.2O 0-6 (mole %) K.sub.2O 0-3 (mole %) MO 0-3 (mole %) (M
= Mg, Ca, Sr, Ba, Zn) Other 0-3 (mole %) SiO.sub.2 balance.
56. The doped sealing glass fiber of claim 54, wherein said
composition is a follows:
36 Al.sub.2O 0-15 (mole %) B.sub.2O.sub.3 10-30 (mole %) Li.sub.2O
0-3 (mole %) Na.sub.2O 3-8 (mole %) K.sub.2O 0-4 (mole %) CuO 0.2-1
(mole %) SnO 0.1-1 (mole %) Br 0.2-1 (mole %) Cl 0-2 (mole %) F 0-6
(mole %) CeO.sub.2 0-3 (mole %) SiO.sub.2 balance.
57. The doped sealing glass fiber of claim 49, wherein said doped
sealing glass fiber is made from a multi-component glass doped with
at least one transition or rare earth metal such as iron, copper,
vanadium, manganese, cobalt, nickel, chromium, neodymium or cerium.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part application of
U.S. patent application Ser. No. 10/414,653, filed Apr. 16, 2003.
The contents of this application are incorporated by reference
herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to hermetically sealed glass
packages that are suitable to protect thin film devices that are
sensitive to the ambient environment. Some examples of such devices
are organic emitting light diode (OLED) displays, sensors, and
other optical devices. The present invention is demonstrated using
OLED displays as an example.
[0004] 2. Description of Related Art
[0005] OLEDs have been the subject of a considerable amount of
research in recent years because of their use and potential use in
a wide variety of electroluminescent devices. For instance, a
single OLED can be used in a discrete light emitting device or an
array of OLEDs can be used in lighting applications or flat-panel
display applications (e.g., OLED displays). The OLED displays are
known as being very bright and having a good color contrast and
wide viewing angle. However, the OLED displays and in particular
the electrodes and organic layers located therein are susceptible
to degradation resulting from interaction with oxygen and moisture
leaking into the OLED display from the ambient environment. It is
well known that the lifetime of the OLED display can be
significantly increased if the electrodes and organic layers within
the OLED display are hermetically sealed from the ambient
environment. Unfortunately, in the past it was very difficult to
develop a sealing process to hermetically seal the OLED display.
Some of the factors that made it difficult to properly seal the
OLED display are briefly mentioned below:
[0006] The hermetic seal should provide a barrier for oxygen
(10.sup.-3 cc/m.sup.2/day) and water (10.sup.-6 g/m.sup.2/day).
[0007] The size of the hermetic seal should be minimal (e.g., <1
mm) so it does not have an adverse effect on size of the OLED
display.
[0008] The temperature generated during the sealing process should
not damage the materials (e.g., electrodes and organic layers)
within the OLED display. For instance, the first pixels of OLEDs,
which are located about 1 mm from the seal in the OLED display
should not be heated to more than 85.degree. C. during the sealing
process.
[0009] The gases released during sealing process should not
contaminate the materials within the OLED display.
[0010] The hermetic seal should enable electrical connections
(e.g., thin-film chromium) to enter the OLED display.
[0011] Today the most common way for sealing the OLED display is to
use different types of epoxies with inorganic fillers and/or
organic materials that form the seal after they are cured by
ultra-violet light. Although these types of seals usually provide
good mechanical strength, they can be very expensive and there are
many instances in which they have failed to prevent the diffusion
of oxygen and moisture into the OLED display. In fact, these epoxy
seals need to use a desiccant to get an acceptable performance.
Another potential way for sealing the OLED display is to utilize
metal welding or soldering, however, the resulting seal can suffer
from the problematical shorting of the electrical leads which enter
the OLED display. This sealing process is also very complex since
several thin film layers are necessary to get good adhesion.
Accordingly, there is a need to address the aforementioned problems
and other shortcomings associated with the traditional seals and
the traditional ways for sealing the OLED displays. These needs and
other needs are satisfied by the hermetic sealing technology of the
present invention.
BRIEF DESCRIPTION OF THE INVENTION
[0012] The present invention includes a hermetically sealed OLED
display and method for manufacturing the hermetically sealed OLED
display. In one embodiment, the hermetically sealed OLED display is
manufactured by providing a first substrate plate and a second
substrate plate. The second substrate contains at least one
transition or rare earth metal such as iron, copper, vanadium,
manganese, cobalt, nickel, chromium, neodymium and/or cerium. OLEDs
are deposited onto the first substrate plate. A laser is then used
to heat the doped second substrate plate in a manner that causes a
portion of it to swell and form a hermetic seal that connects the
first substrate plate to the second substrate plate and also
protects the OLEDs. The second substrate plate is doped with at
least one transition or rare earth metal such that when the laser
energy is absorbed there is an increase in temperature in the
sealing area. Another embodiment for manufacturing OLED displays is
also described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] A more complete understanding of the present invention may
be obtained by reference to the following detailed description when
taken in conjunction with the accompanying drawings wherein:
[0014] FIGS. 1A and 1B are a top view and a cross-sectional side
view illustrating the basic components of a hermetically sealed
OLED display in accordance with a first embodiment of the present
invention;
[0015] FIG. 2 is a flowchart illustrating the steps of a preferred
method for manufacturing the hermetically sealed OLED display shown
in FIGS. 1A and 1B;
[0016] FIGS. 3A and 3B are photographs of partial top views of a
substrate plate and sealing glass plate that were at least
partially sealed to one another using a 20 watt laser and a 25 watt
laser in accordance with the method shown in FIG. 2;
[0017] FIG. 4 is a graph that shows the profiles of the swelled
region on the free surface of the first embodiment of the doped
substrate plate that were made using a 810 nm laser operating at 15
watts, 20 watts and 25 watts;
[0018] FIG. 5 is a graph that shows the height variation of the
swelled region shown in FIG. 4 for the laser operating at 20
watts;
[0019] FIG. 6 is a graph that shows the thermal expansion curves of
a substrate plate (glass code 1737 made by Corning Inc. and two
sealing glass plates (composition nos. 4-5) that can be used to
make glass packages in accordance with the method shown in FIG.
2;
[0020] FIG. 7 is a photograph of 1737 substrate plate that was
sealed to sealing glass plate (composition no. 5) in experiment
#2;
[0021] FIG. 8 is a photograph of 1737 substrate plate that was
sealed to sealing glass plate (composition no. 5) in experiment
#3;
[0022] FIG. 9 is a graph that shows the thermal expansion curves of
1737 and three sealing glass plates (composition nos. 6-8) that can
be used to make glass packages in accordance with the method shown
in FIG. 2;
[0023] FIGS. 10A and 10B are a top view and a cross-sectional side
view illustrating the basic components of a hermetically sealed
OLED display in accordance with a second embodiment of the present
invention;
[0024] FIG. 11 is a flowchart illustrating the steps of a preferred
method for manufacturing the hermetically sealed OLED display shown
in FIGS. 10A and 10B;
[0025] FIG. 12 is a photograph of a top view of a melted fiber
which bonded two substrates together using a 25-watt laser beam in
accordance with the method shown in FIG. 11; and
[0026] FIG. 13 is a cross-sectional side view illustrating a
laminated sealing glass plate that can be used to make a
hermetically sealed OLED display or a glass package in accordance
with yet another embodiment of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0027] Referring to FIGS. 1-13, there are disclosed in accordance
with the present invention three embodiments of hermetically sealed
OLED displays 100', 100" and 100". Although the sealing process of
the present invention is described below with respect to the
fabrication of hermetically sealed OLED displays 100', 100" and
100'", it should be understood that the same or similar sealing
process can be used in other applications to protect sensitive
optical/electronic devices that are disposed between two glass
plates. Accordingly, the present invention should not be construed
in a limited manner.
[0028] Referring to FIGS. 1A and 1B there are a top view and a
cross-sectional side view illustrating the basic components of the
first embodiment of the hermetically sealed OLED display 100'. The
OLED display 100' includes a multilayer sandwich of a substrate
plate 102' (e.g., glass plate 102'), an array of OLEDs 104' and a
sealing glass plate 106' that was doped with at least one
transition or rare earth metal such as iron, copper, vanadium,
manganese, cobalt, nickel, chromium, neodymium and/or cerium (for
example). The OLED display 100' has a hermetic seal 108' formed
from the sealing glass plate 106', which protects the OLEDs 104'
located between the substrate plate 102' and the sealing glass
plate 106'. The hermetic seal 108' is typically located just inside
the outer edges of the OLED display 100'. And, the OLEDs 104' are
located within the perimeter of the hermetic seal 108'. How the
hermetic seal 108' is formed from the sealing glass plate 106' and
the components such as the laser 110 and lens 114, which are used
for forming the hermetic seal 108' are described in greater detail
below with respect to FIGS. 2-9.
[0029] Referring to FIG. 2, there is a flowchart illustrating the
steps of the preferred method 200 for manufacturing the
hermetically sealed OLED display 100'. Beginning at step 202, the
substrate plate 102' is provided so that one can make the OLED
display 100'. In the preferred embodiment, the substrate plate 102'
is a transparent glass plate like the one manufactured and sold by
Corning Incorporated under the brand names of Code 1737 glass or
Eagle 2000.TM. glass. Alternatively, the substrate plate 102' can
be a transparent glass plate like the ones manufactured and sold by
the companies like Asahi Glass Co. (e.g., OA10 glass and OA21
glass), Nippon Electric Glass Co., NHTechno and Samsung Corning
Precision Glass Co. (for example).
[0030] At step 204, the OLEDs 104' and other circuitry are
deposited onto the substrate plate 102'. The typical OLED 104'
includes an anode electrode, one or more organic layers and a
cathode electrode. However, it should be readily appreciated by
those skilled in the art that any known OLED 104' or future OLED
104' can be used in the OLED display 100'. It should also be
appreciated that this step can be skipped if an OLED display 100'
is not being made but instead a glass package is being made using
the sealing process of the present invention.
[0031] At step 206, the sealing glass plate 106' is provided so
that one can make the OLED display 100'. In the preferred
embodiment, the sealing glass plate 106' is made from a
borosilicate (multicomponent) glass that is doped with at least one
transition or rare earth metal such as iron, copper, vanadium,
manganese, cobalt, nickel, chromium, neodymium and/or cerium (for
example). The compositions of several exemplary sealing glass
plates 106' are provided below with respect to TABLES 1-5.
[0032] At step 208, a predetermined portion 116' of the sealing
glass plate 106' is heated in a manner so that portion 116' of the
sealing glass plate 106' can swell and form the hermetic seal 108'
(see FIG. 1B). The hermetic seal 108' connects and bonds the
substrate plate 102' to the sealing glass plate 106'. In addition,
the hermetic seal 108' protects the OLEDs 104' from the ambient
environment by preventing oxygen and moisture in the ambient
environment from entering into the OLED display 100'. As shown in
FIGS. 1A and 1B, the hermetic seal 108' is typically located just
inside the outer edges of the OLED display 100'.
[0033] In the preferred embodiment, step 208 is performed by using
a laser 110 that emits a laser beam 112 through a lens 114
(optional) and through the substrate plate 102' so as to heat the
predetermined portion 108' of the doped sealing glass plate 106'
(see FIG. 1B). The substrate plate 102' does not absorb the laser
energy which helps minimize heat dissipation to organic layers in
the OLED device. The laser beam 112 is moved such that it
effectively heats a portion 116' of the doped sealing glass plate
106' and causes that portion 116' of the sealing glass plate 106'
to swell and form the hermetic seal 108'. The laser 110 has a laser
beam 112 with a specific wavelength and the sealing glass plate
106' is doped with a transition or rare earth metal so as to
enhance its absorption property at the specific wavelength of the
laser beam 112. This connection between the laser 110 and sealing
glass plate 106' means that when the laser beam 112 is emitted onto
the doped sealing glass plate 106' at point 116' there is an
increase of absorption of the laser beam 112 at that point 116'
which causes the sealing glass plate 106' to swell and form the
hermetic seal 108'. Because of the increase in the absorption of
heat energy in the doped sealing glass plate 106', the laser beam
112 can move relatively fast over the sealing glass plate 106' and
form the hermetic seal 108'. And, by being able to move the laser
beam 112 fast this in effect minimizes the undesirable transfer of
heat from the forming hermetic seal 108' to the OLEDs 104' within
the OLED display 100'. Again, the OLEDs 104' should not be heated
to more than 85.degree. C. during the operation of the laser
110.
[0034] Described below are several experiments that were conducted
by one or more of the inventors. Basically, the inventors have
experimented with and used different regimes of the laser 110 to
connect and bond different types of substrate plates 102' to
different types of sealing glass plates 106'. The compositions of
these exemplary sealing glass plates 106' are provided in TABLE
1.
1 TABLE 1 Composition Mole % 1* 2* 3* 4* 5* 6* 7* 8* SiO.sub.2 79.8
79.5 79.2 78.6 47 47 47 47 Na.sub.2O 5.3 5.3 5.3 5.2 0 0 0 0
Al.sub.2O.sub.3 1.2 1.1 1.1 1.1 9.0 9 9 9 B.sub.2O.sub.3 13.7 13.7
13.6 13.5 27 27 27 27 Fe.sub.2O.sub.3 0 0.4 0.8 1.6 0 0 0 0 PbO 0 0
0 0 7 0 0 0 CuO 0 0 0 0 10 17 10 10 ZnO 0 0 0 0 0 0 7 0 SrO 0 0 0 0
0 0 0 7 *These compositions are associated with the exemplary
sealing glass plates 106'.
[0035] As can be seen in TABLE 1, each of the exemplary sealing
glass plates 106' has a different type and/or concentration of
oxides such as Fe.sub.2O.sub.3, PbO, CuO, ZnO, and SrO (for
example). It should be noted that some of these elements are not
transition or rare earth metals and some of these elements were not
added to induce absorption. The sealing glass plates 106' in these
experiments had an enhanced optical absorption in the near-infrared
region and in particular at the 810-nm wavelength. The selection of
transition-metal dopants is based on the glass absorption at the
laser wavelength which again in these experiments is 810 nm. The
dopants were selected to absorb at the wavelength of the laser beam
112 which in these experiments was 810 nm. And, the substrate plate
102' can be chosen such that it does not absorb at 810 nm. Because
the optical absorption of the sealing glass plate 106' is enhanced
to correspond with the particular wavelength of the laser 110, the
laser 110 is able to move relatively fast to heat the doped sealing
glass plate 106' so that it can form the hermetic seal 108' while
at the same time not overheat the OLEDs 104'.
[0036] It should be readily appreciated that in addition to the
aforementioned compositions listed in TABLE 1, there may be other
compositions of substrate plates 102' and doped sealing glass plate
106' which exist like those listed in TABLES 3-5 or which have yet
to be developed but could be connected to one another in accordance
with the present invention to make a desirable OLED display
100'.
[0037] The optical absorption measurements from several experiments
along with the physical properties of the exemplary substrate
plates 102' and exemplary doped sealing glass plates 106' are
provided below in TABLE 2.
2 TABLE 2 Composition Eagle 1* 2* 3* 4* 5* 6* 7* 8* 1737 2000
Fe.sub.2O.sub.3 or CuO 0 0.4 0.8 1.6 10 -- -- -- -- -- Mole %
Thickness 2.02 2.04 2.12 2.1 0.66 -- -- -- -- -- (mm) Transmission
92.11 46.77 15.66 0.63 0.48 -- -- -- -- -- % at 810 nm Absorption 0
0.144 0.363 1.031 3.46 -- -- -- -- -- coefficient,/ mm % Absorbed 0
3 7.4 19.4 50.5 -- -- -- -- -- in 100 micron layer % Absorbed 0 5.9
14.2 34.8 73.3 -- -- -- -- -- in 200 micron layer Thermal -- -- --
3.9 3.7 3.0 3.35 4.2 4.2 3.61 Expansion (ppm/.degree. C.) to strain
point Annealing -- -- -- -- -- 482 526 526 721 722 Temperature
(.degree. C.) Strain Point -- -- -- -- -- 443 486 488 666 666
(.degree. C.) *These compositions are associated with the exemplary
sealing glass plates 106'.
[0038] As can be seen in TABLE 2, the desired degree of laser
energy absorption can be achieved by: (1) selecting the particular
transition or rare earth metal (s) to be incorporated within the
sealing glass plate 106' and (2) selecting the concentration or
amount of transition or rare earth metal(s) to be incorporated
within the sealing glass plate 106'.
[0039] Experiment #1
[0040] In this experiment, a 25 watt laser 110 was used to focus a
810 nm continuous-wave laser beam 112 through the substrate plate
102' (e.g., 1737 glass substrate) onto the sealing glass plate 106'
(composition no. 4) (see FIG. 1B). The laser beam 112 moved at a
speed of lcm/s to form the seal 108' which connected the substrate
plate 102' to the sealing glass plate 106'. FIGS. 3A and 3B are
photographs taken by an optical microscope of partial top views of
two plates 102' and 106' that were at least partially connected to
one another using a 25 watt laser beam 112. As can be seen, very
good seals 108' were obtained when the laser 100 had a power
setting of 20 and 25 watts. The seals 108' are approximately 250
microns wide in FIG. 3A and 260 microns wide in FIG. 3B. The
sealing glass plate 106' swelled and formed a miniscule or ridge
during melting which created a gap of approximately 8 microns
between the substrate plate 102' and sealing glass plate 106'. This
gap is sufficient to accommodate OLEDs 104' (not present) which are
approximately 2 microns thick. The profiles of the ridges at
various laser powers are shown in the graph of FIG. 4. As can be
seen, the height of the ridges ranged from approximately 9 .mu.m
using a 15 watt laser 110 to approximately 12.5 .mu.m using a 25
watt laser 110. The graph in FIG. 5 shows the height variation of
the ridge made by the 20-watt laser. This ridge is relatively
uniform over its length since its height fluctuates approximately
+/-250 nm.
[0041] Unfortunately, difficulties were encountered in closing the
seal 108' around the edges of the two aforementioned exemplary
glass plates 102' and 106' (1737 glass substrate and composition
no. 4) due to the presence of significant residual stresses. In
particular, cracking was observed if the laser beam 112 passed over
an already-swelled region in the sealing glass plate 106'
(composition no. 4). Thus, the inventors decided to explore other
glass compositions to solve this seal-closing problem. In doing
this, the inventors noted that the physical properties (e.g.,
strain point and thermal expansion) of sealing glass plates 106 and
106' (composition nos. 4 and 5) indicated that it may be possible
to lower the problematical residual stresses. FIG. 6 is a graph
that shows the thermal expansion curves of the substrate plate 102'
(1737 glass substrate) and two sealing glass plates 106'
(composition nos. 4 and 5). As can be seen, the mismatch strain
between substrate plate 102' (1737 glass substrate) and sealing
glass plate 106' (composition no. 5) which is 80 ppm is
significantly lower when compared to the mismatch strain between
substrate plate 102' (1737 glass substrate) and sealing glass plate
106' (composition no. 4) which is 360 ppm. As such, when a laser
110 was used to connect substrate plate 102' (1737 glass substrate)
to sealing glass plate 106' (composition no. 5) cracks were not
present when the seal 108' crossed over itself at 90.degree..
Moreover, because the sealing glass plate 106' (composition no. 5)
is softer and contains more energy absorbing transition metal(s)
than sealing glass plate 106' (composition no. 4), the laser power
required for good sealing was 50% less when compared to the laser
power needed to seal the sealing glass plate 106' (composition no.
4).
[0042] Experiment #2
[0043] To test the gas leakage through the seal 108' between two
plates 102' and 106', a helium-leak test was developed. A
50.times.50.times.0.7 mm substrate plate 102' (1737 glass
substrate) with a 3 mm diameter hole at its center was sealed to a
50.times.50.times.4 mm sealing glass plate 106' (composition no. 5)
(see photograph in FIG. 7). The sample was sealed using a 810 nm
laser 110 with a power of 8.5 W and velocity of 15 mm/s. After
sealing the two plates 102' and 106', the pressure in the sealed
cavity was reduced by connecting a vacuum pump to the hole in the
substrate plate 102'. The sealed region was pumped down to a
pressure of<50 m-torr and helium gas was sprayed around the
outer edge of the seal 108'. The helium gas leak rate through the
seal 108' was measured with a detector. The lowest helium leak rate
that can be measured with the apparatus is 1.times.10.sup.-8 cc/s.
The Helium leak rate through the seal 108' was below the detection
limit of the instrument. This is indicative of a very good seal
108'.
[0044] Experiment #3
[0045] To further test the gas leakage through the seal 108' in the
two plates 102' and 106' of experiment #2, a calcium leak test was
developed. Using an evaporation technique, a thin film of calcium
approximately 31.times.31.times..0005 mm was deposited on a
50.times.50.times.0.7 mm substrate plate 102' (1737 glass
substrate). This plate was sealed to a 50.times.50.times.4 mm
sealing glass plate 106' (composition no. 5) under the same sealing
conditions described in experiment #2. To demonstrate hermetic
performance, the sealed plates 102' and 106' were aged in
(85.degree. C./85RH environment (see photograph in FIG. 8). This
sample was visually inspected periodically to determine whether
there was any change in the appearance of the calcium film. If the
calcium film is not protected, it reacts with the moisture in the
ambient and becomes transparent in a few hours. There was no change
in the appearance of calcium film after aging for 2000 hours in the
85.degree. C./85RH environment. This is indicative of a very good
seal 108'.
[0046] Experiment #4
[0047] The sealing glass plate 106' (composition no. 5) contains
lead (PbO) in its composition. Glasses containing lead are not
generally preferred because of environmental concerns. Therefore,
several lead free glass compositions were tested. The compositions
of these sealing glass plates 106' (composition nos. 6-8) were
provided in TABLE 1 and their physical properties are given in
Table 2. The thermal expansion curves of sealing glass plates 106'
(composition nos. 6-8) and substrate plate 102' (1737 glass
substrate) are shown in FIG. 9. All of these sealing glass plates
106' showed swelling during heating and excellent bonding to
substrate plate 102' (1737 glass substrate). A sample of sealing
glass plate 106' (composition no. 7) was sealed to substrate glass
plate 102' (1737 glass substrate) for calcium test. The sealing was
done with an 8.5 watt laser 110 having a velocity of 15 mm/sec. The
sample was aged in 85.degree. C./85RH environment to determine
hermetic performance. There was no change in the appearance of the
calcium film even though the sample was exposed to this severe
moist environment for more than 1800 hours.
[0048] Experiment #5
[0049] Four calcium test samples were made with substrate plate
102' (1737 glass substrate) and sealing glass plate 106'
(composition no. 7) using the same sealing conditions described in
experiment #4. These samples were subjected to a thermal cycling
test between -40.degree. C. to 85.degree. C. The rate of heating
during temperature cycling was 2.degree. C./min with 0.5 hour hold
at -40.degree. C. and 85.degree. C. (time for each cycle is 3
hours). There was no change in the appearance of the calcium film
even after 400 thermal cycles. This indicates that the seal is very
robust.
[0050] It should be noted that the sealing method of the present
invention is very rapid and is also amenable to automation. For
example, sealing a 40.times.40 cm OLED display 100' can take
approximately 2 minutes. And, the doped sealing glass plates 106'
can be manufactured using a float glass process, a slot draw
process or a rolling process since the glass surface quality is not
that critical for the sealing plate of front-emitting OLED displays
100'.
[0051] Referring to FIGS. 10A and 10B there are respectively a top
view and a cross-sectional side view illustrating the basic
components of a second embodiment of the hermetically sealed OLED
display 100". The OLED display 100" includes a multi-layer sandwich
of a first substrate plate 102" (e.g., glass plate 102"), an array
of OLEDs 104", a sealing glass fiber 106" that was doped with at
least one transition or rare earth metal such as iron, copper,
vanadium, manganese, cobalt, nickel, chromium, neodymium and/or
cerium (for example) and a second substrate plate 107" (e.g., glass
plate 107"). The OLED display 100" has a hermetic seal 108" formed
from the sealing glass fiber 106" which protects the OLEDs 104"
located between the first substrate plate 102" and the second
substrate plate 107". The hermetic seal 108" is typically located
just inside the outer edges of the OLED display 100". And, the
OLEDs 104" are located within a perimeter of the hermetic seal
108". How the hermetic seal 108" is formed from the sealing glass
fiber 106" and the components such as the laser 110 and lens 114
which are used for forming the hermetic seal 108" are described in
greater detail below with respect to the method 1100 and FIGS.
11-12.
[0052] Referring to FIG. 11, there is a flowchart illustrating the
steps of the preferred method 1100 for manufacturing the
hermetically sealed OLED display 100". Beginning at step 1102, the
first substrate plate 102" is provided so that one can make the
OLED display 100". In the preferred embodiment, the first substrate
plate 102" is a transparent glass plate like the ones manufactured
and sold by Corning Incorporated under the brand names of Code 1737
glass or Eagle 2000.TM. glass. Alternatively, the first substrate
plate 102" can be a transparent glass plate like the ones
manufactured and sold by the companies like Asahi Glass Co. (e.g.,
OA10 glass and OA21 glass), Nippon Electric Glass Co., NHTechno and
Samsung Corning Precision Glass Co. (for example).
[0053] At step 1104, the OLEDs 104" and other circuitry are
deposited onto the first substrate plate 102". The typical OLED
104" includes an anode electrode, one or more organic layers and a
cathode electrode. However, it should be readily appreciated by
those skilled in the art that any known OLED 104" or future OLED
104" can be used in the OLED display 100". Again, it should be
appreciated that this step can be skipped if an OLED display 100"
is not being made but instead a glass package is being made using
the sealing process of the present invention.
[0054] At step 1106, the second substrate plate 107" is provided so
that one can make the OLED display 100". In the preferred
embodiment, the second substrate plate 107" is a transparent glass
plate like the ones manufactured and sold by Corning Incorporated
under the brand names of Code 1737 glass or Eagle 2000.TM. glass.
Alternatively, the second substrate plate 107" can be a transparent
glass plate like the ones manufactured and sold by the companies
like Asahi Glass Co. (e.g., OA10 glass and OA21 glass), Nippon
Electric Glass Co., NHTechno and Samsung Corning Precision Glass
Co. (for example).
[0055] At step 1106, the sealing glass fiber 106" is deposited
along the edge of the second substrate plate 107". In the preferred
embodiment, the sealing glass fiber 106" has a rectangular shape
and is made from a silicate glass that is doped with at least one
transition or rare earth metal such as iron, copper, vanadium,
manganese, cobalt, nickel, chromium, neodymium and/or cerium (for
example). The compositions of several exemplary sealing glass
fibers 106" are provided above in TABLES 1.
[0056] At step 1108, the OLEDs 104" and other circuitry are placed
on the first substrate plate 102" or on the second substrate plate
107". The typical OLED 104" includes an anode electrode, one or
more organic layers and a cathode electrode. However, it should be
readily appreciated by those skilled in the art that any known OLED
104" or future OLED 104" can be used in the OLED display 100".
[0057] At step 1110, the sealing glass fiber 106" is heated by the
laser 110 (or other heating mechanism such as an infrared lamp) in
a manner so that it can soften and form the hermetic seal 108" (see
FIG. 10B). The hermetic seal 108" connects and bonds the first
substrate plate 102" to second substrate plate 107". In addition,
the hermetic seal 108" protects the OLEDs 104" from the ambient
environment by preventing oxygen and moisture in the ambient
environment from entering into the OLED display 100". As shown in
FIGS. 10A and 10B, the hermetic seal 108" is typically located just
inside the outer edges of the OLED display 100".
[0058] In the preferred embodiment, step 1110 is performed by using
a laser 110 that emits a laser beam 112 through a lens 114
(optional) onto the first substrate plate 102" so as to heat the
sealing glass fiber 106" (see FIG. 10B). The laser beam 112 is
moved such that it effectively heats and softens the sealing glass
fiber 106" so that it can form the hermetic seal 108". Again, the
hermetic seal 108" connects the first substrate plate 102 to the
second substrate plate 107. In particular, the laser 110 outputs a
laser beam 112 having a specific wavelength (e.g., 800 nm
wavelength) and the sealing glass fiber 106" is doped with a
transition or rare earth metal (e.g., copper, vanadium, iron,
manganese, cobalt, nickel, chromium, neodymium, cerium) so as to
enhance its absorption property at the specific wavelength of the
laser beam 112. This enhancement of the absorption property of the
sealing glass fiber 106" means that when the laser beam 112 is
emitted onto the sealing glass fiber 106" there is an increase of
absorption of heat energy from the laser beam 112 into the sealing
glass fiber 106" which causes the sealing glass fiber 106" to
soften and form the hermetic seal 108". The substrate glass plates
102" and 107" (e.g., 1737 glass substrate and Eagle 2000 glass
substrate) are chosen such that they do not absorb much heat if any
from the laser 110. As such, the substrate plates 102 and 107 have
a relatively low absorption properties at the specific wavelength
of the laser beam 112 which helps to minimize the undesirable
transfer of heat from the forming hermetic seal 108" to the OLEDs
104" within the OLED display 100". Again, the OLEDs 104" should not
be heated to more than 85.degree. C. during the sealing process.
FIG. 12 is photograph of a top view of two substrate plates 102"
and 107" (1737 glass substrate and Eagle 2000 glass substrate) that
were bonded together using a 25-watt laser beam 112 that was moved
at 1 cm/s velocity and focused to an approximate spot of 0.2 mm-0.3
mm onto the sealing glass fiber 106" (composition no. 4). The width
of the seal 108" in FIG. 12 is approximately 100 microns.
[0059] Described below are additional glass compositions of the
sealing glass plate 106' (first embodiment) and the sealing glass
fiber 106" (second embodiment) and additional laser wavelengths
that can be used to form hermetic seals 108' and 108" in OLED
displays 100' and 100". In particular, additional glass
compositions are described below that are suitable for sealing OLED
displays 100' and 100" using an 810 nm infrared (1R) laser 110.
Also, glass compositions are described below that are suitable for
sealing OLED displays 100' and 100" using a 532 nm visible laser
110. Moreover, glass compositions are described below that are
suitable for sealing OLED displays 100' and 100" using a 355 nm
ultraviolet (UV) laser 110. Each of these glass compositions are
described in detail below with respect to TABLES 3-5.
[0060] Referring to IR absorbing glasses, in the text and
experiments described above with respect to TABLES 1 and 2, the IR
absorbing glasses 106' and 106" which contained transition metal
elements had a strong absorption in the infrared range for sealing
with an 810 nm laser 110. However, some of the aforementioned
glasses like composition nos. 5-8 listed in TABLE 1 which had over
about 10 mole % of a transition metal tended to have a dull
appearance after pouring and annealing due to the formation of a
copper oxide layer on the surface. In these copper borosilicate
glasses, it was found that the oxidation phenomenon was dependent
on copper and alumina concentrations in the doped glass. In
contrast, the surface appearance of the glass composition no. 9
(TABLE 3A) which has a lower Cu plus some Fe did not have a dull
appearance and performed well in a 85.degree. C./85RH hermetic
performance test (>500 hours).
3 TABLE 3A comp. #9 oxides mole % weight % SiO.sub.2 58.5 52.06
Al.sub.2O.sub.3 4 6.04 B.sub.2O.sub.3 28 28.87 Na.sub.2O 0 0
V.sub.2O.sub.5 0 0 Fe.sub.2O.sub.3 1.5 3.55 CuO 8 9.42
[0061] Also, in recent experiments, optical transmission data had
been obtained which indicated that there are interactions between
some transition metal ions which give rise to significantly higher
absorption than predicted by the sum of the individual elements.
For instance, glass compositions nos. 10-11 (TABLE 3B) have shown
that vanadium ions have a strong interaction with copper and iron
ions.
4 TABLE 3B comp. comp. no. 10 no. 11 oxides mole % weight % mole %
weight % SiO.sub.2 81.84 72.37 81.84 77.16 Al.sub.2O.sub.3 1.21
1.82 1.21 1.94 B.sub.2O.sub.3 10.56 10.83 10.56 11.53 Na.sub.2O
5.38 4.9 5.38 5.22 V.sub.2O.sub.5 2 5.36 1 2.86 Fe.sub.2O.sub.3 2
4.7 0 0 CuO 0 0 1 1.25
[0062] This synergistic effect of the interaction of metal ions
also occurred in glass composition nos. 12-17 (TABLE 3C). As can be
seen in TABLE 3C, the increase of absorbing ions by 50% in going
from glass composition no. 13 to glass composition no. 17 resulted
in the absorption increasing roughly fourfold.
5TABLE 3C mole % comp. comp. comp. comp. comp. comp. comp. comp.
comp. no. no. no. oxide no. 12 no. 13 no. 14 no. 15 no. 16 no. 17
18 19 20 SiO.sub.2 65.6 68.6 69.6 69.6 69.6 67.1 73 73 50
Al.sub.2O.sub.3 4 4 4 4 4 4 1 1 9 B.sub.2O.sub.3 24.2 24.2 24.2
24.2 24.2 24.2 23.6 23.6 30 Li.sub.2O 0.2 0.2 0.2 0.2 0.2 0.2 1.5
1.5 0 Na.sub.2O 0 0 0 0 0 0 0.5 0.5 0 K.sub.2O 0 0 0 0 0 0 0.4 0.4
0 ZnO 0 0 0 0 0 0 0 0 3 Fe.sub.2O.sub.3 0 1 1 1 0 1.5 0 0 8
V.sub.2O.sub.5 2 1 0 1 1 1.5 2 4 0 CuO 0 0 0 0 0 0 1 1 0 TiO.sub.2
2 1 1 0 1 1.5 0 0 0 NiO 0 0 0 0 0 0 0 0 0 MnO.sub.2 0 0 0 0 0 0 0 0
0 CTE 34 41 na 810 abs 0.6 4.8 0.5 4 0.2 18.8 na na na glassy? yes
yes yes yes yes yes yes phase sep
[0063] However, referring to glass composition nos. 18-19 (TABLE
3C) it can be seen that by exceeding certain levels of some
elements, for instance V, can result in an increase in the CTE to
undesirable values. And, referring to glass composition no. 20 it
can be seen that when compositions have too much Fe203 this can
result in phase separation. Phase separation does not necessarily
render a glass unsuitable for sealing, but it does make the
manufacturing of sheet much more difficult, and is viewed as
undesirable.
[0064] In view of the data in TABLES 3A-3C, a preferred composition
range for infrared sealing glasses 106' and 106" that can be used
in this embodiment of the present invention has been determined and
is listed in TABLE 3D:
6 TABLE 3D Oxide Mole % Fe.sub.2O.sub.3 0.0-5 V.sub.2O.sub.5 0.0-4
TiO.sub.2 0.0-5 CuO 0.0-10 NiO 0.0-3 B.sub.2O.sub.3 8-30
Al.sub.2O.sub.3 1.2-12 Li.sub.2O 0-2 Na.sub.2O 0-6 K.sub.2O 0-3 MO
0-3 (M = Mg, Ca, Sr, Ba, Zn) Other 0-3 SiO.sub.2 Balance, typically
45-80
[0065] Referring now to visible absorbing glasses, these glasses
typically contain cobalt ions so they have a very strong absorption
in the visible region (450-650 nm) and weaker absorption in the IR
region. There are several visible glass composition families that
can act as successful hosts to cobalt ions. Examples of these
visible glass compositions are shown in TABLE 4A. As can be seen,
the high boron glass composition nos. 20-23 have the advantage that
they have lower softening and strain points, which means that
sealing can be accomplished at somewhat lower laser energy which in
turn means the sealing is less likely to cause seal excessive
stresses. On the other hand, the high boron glasses and in
particular glass composition no. 22 have a greater tendency to
undergo phase separation. This phenomenon can be triggered by
excessive transition metal additions.
7 TABLE 4A mole % (comp. (comp. (comp. (comp. oxide 20) no 21) no
22) no 23) SiO.sub.2 80.8 79.8 78.8 77 Al.sub.2O.sub.3 1.2 1.2 1.2
0 B.sub.2O.sub.3 10.6 10.6 10.6 21.4 Li.sub.2O 0 0 0 0 Na.sub.2O
5.4 5.4 5.4 0 K.sub.2O 0 0 0 1.6 Co.sub.3O.sub.4 2 3 4 1 glassy yes
yes phase yes sep CTE 42 40 na 31 abs., mm-1 na 6 at 532 nm
[0066] The table also shows that in borosilicate glass,
CO.sub.3O.sub.4 additions are tolerated up to about 3 mole %, after
which phase separation takes place, rendering the composition
unsuitable for manufacturing. However, in a high boron glass, 1
mole % CO.sub.3O.sub.4 appears to be sufficient since it results in
an absorption coefficient of 6 mm.sup.-1, well above the threshold
value of about 3 mm.sup.-1 for successful sealing. It should also
be noticed that a low alkali glass like glass composition no. 23
which has a lower CTE than the two lower boron glass composition
nos. 20-21 is desirable.
[0067] It should be appreciated that most of the aforementioned IR
absorbing glasses also absorb strongly in the visible wavelength as
well. In fact, there are several transition metals, alone and in
combination, which were listed in the description of IR absorbing
glasses that can yield useful visible absorption. However, there
are several reasons why one would want to have a glass 106' and
106" designed to absorb primarily in the visible region. One such
reason is that glasses with strong visible absorption and less
strong infrared absorption may be easier to manufacture from the
standpoint of melting and forming into a glass sheet. Another
reason for using visible absorbing glasses with strong absorptions
in the visible region like the ones described above is that they
can be used in display devices that have a "bottom emission"
geometry, i.e., light is emitted through the transparent OLED
substrate glass.
[0068] In view of the data associated with TABLE 4A, a preferred
composition range for visible sealing glasses 106' and 106" that
can be used in this embodiment of the present invention has been
determined and as listed in TABLE 4B:
8 TABLE 4B Oxide Mole % *Co.sub.3O.sub.4 0.5-3 B.sub.2O.sub.3 8-30
Al.sub.2O 1.2-12 Li.sub.2O 0-2 Na.sub.2O 0-6 K.sub.2O 0-3 MO 0-3 (M
= Mg, Ca, Sr, Ba, Zn) Other 0-3 SiO.sub.2 Balance, typically 45-80
*The use of cobalt as an absorber is preferred in this application
for at least three reasons. First, while cobalt ions do absorb
strongly at the useful laser wavelength of 532 nm, they do not
absorb nearly as much in the infrared region. Second, since cobalt
is such a strong colorant on a molar or weight basis, smaller
additions are required to get to useful absorption levels. Third,
cobalt is among the most effective additives because of its higher
absorption per mole % oxide added. Following are some more results
associated with two experiments that were conducted with cobalt
doped glass.
[0069] A cobalt doped sample (composition in mole %;
SiO.sub.2=74.77, B.sub.2O.sub.3=20.77, K.sub.2O=1.55, Co304=2.91)
was sealed to 1737 using a 532 nm continuous wave laser with 8
watts of power at 10 mm/s. To demonstrate that the seal was
hermetic a calcium film (0.5 micron thick) was deposited on 1737
substrate in the encapsulated area prior to sealing. The sealed
samples w aged in 85.degree. C./85RH to accelerate water diffusion
through the seal. There was no change in the appearance of calcium
film even after 5000 hours of aging in 85.degree. C./85RH
environment. If the calcium film is not protected it will lose its
metallic appearance within a few hours under ambient
conditions.
[0070] And, to prove that harder glasses (higher softening
temperature) can be sealed by conducting sealing experiments at
elevated temperatures, Corning Code 1737 glass was doped with 2
mole % CO.sub.3O.sub.4. This glass was first sealed to 1737
substrate at RT with a 532 nm laser (8 W and 7 mm/s). Cracks were
observed both along the seal line and at seal intersections. A
similar sample of cobalt doped 1737 was sealed to 1737 by heating
the sample to 350.degree. C. using the same laser conditions. This
sample did not develop cracks because the thermal stresses
generated during sealing are lower compared to RT sealed sample.
This indicates that there would be some widening to the
aforementioned physical property constraints listed above in TABLE
4B.
[0071] Referring now to UV absorbing glasses, there are two types
of uv-absorbing glasses 106' and 106" described below. In the first
type, borosilicate glasses with Ce and Ce.sup.+ Ti additions have
been found to give adequate absorption for sealing at 355 nm. TABLE
5A lists several glass composition nos. 24-26 where Ce and Ti were
added to borosilicate glass.
9TABLE 5A mole % (comp. (comp. (comp. (comp. (comp. no. no. no. no.
oxide no 24) 25) 26) 27) 28) SiO.sub.2 80.8 78.8 76.8 62 63.6
Al.sub.2O.sub.3 1.2 1.2 1.2 6 6 B.sub.2O.sub.3 10.6 10.6 10.6 28 25
Li.sub.2O 0 0 0 0 0 Na.sub.2O 5.4 5.4 5.4 0 1.4 K.sub.2O 0 0 0 0 0
CeO.sub.2 1 2 2 4 4 TiO.sub.2 1 2 4 0 0 glassy yes yes phase phase
yes sep sep CTE 40 41 na na 34 abs., 6.1 >10 na na 5.5 mm-1 355
nm
[0072] As can be seen in TABLE 5A with respect to glass composition
no. 26, when there is too high a level of Ti in the borosilicate
glass this can cause phase separation. It can also be seen that an
absorption sufficient for sealing was obtained in glass composition
no. 24, although the CTE is a bit high. And, it can be seen in the
other high boron glasses like glass composition nos. 27-28 which
have lower CTEs and lower strain points that they can be used to
make a better seal with substrates which have 40 and below CTEs.
However, these high boron glasses also have a greater tendency for
phase separation like glass composition no. 27. As such, lower
alkali levels may be needed in the high boron glasses to avoid high
CTEs. But, lower alkali glasses also give weaker Ce absorption in
the UV region. A compromise was reached in glass composition no.
28, where only a small amount of alkali was required to avoid phase
separation.
[0073] It should be appreciated that the aforementioned UV
absorbing glasses are fairly transparent in the visible region
(yellow amber color) and have strong absorption at 355 nm. As a
result, these UV absorbing glasses may be used to make top emission
OLED displays. This is important since the market place is likely
to move from bottom emission displays to top emission displays.
[0074] Following is an experiment associated with Ce-doped glass, a
cerium containing glass sample (composition in mole %:
SiO.sub.2=63.6, B.sub.2O.sub.3=25, Na.sub.2O=1.4,
Al.sub.2O.sub.3=6, CeO.sub.2=4; CTE=3.07 ppm/.degree. C. and
absorption coefficient at 355 nm=5.52/mm) was sealed to Eagle 2000
substrate using a 355 nm pulsed laser. A calcium film was deposited
on Eagle 2000 substrate in the encapsulated area to demonstrate
that the seal was hermetic. The sealing conditions used were;
average laser power 8.3 W, speed 15 mm/s, pulse frequency=50 kHz,
pulse width<30 ns. The sealed sample with calcium film was aged
in 85.degree. C./85RH environment. No change in the appearance of
the calcium film was noticed even after 2000 hours in 85.degree.
C./85RH test.
[0075] In view of the data in TABLE 5A, a preferred composition
range for UV absorption Ce and Ti addition sealing glasses 106' and
106" that can be used in this embodiment of the present invention
has been determined and is listed in TABLE 5B:
10 TABLE 5B Oxide Mole % CeO.sub.2 1-4 TiO.sub.2 0.0-3
B.sub.2O.sub.3 8-30 Al.sub.2O.sub.3 1.2-12 Li.sub.2O 0-2 Na.sub.2O
0-6 K.sub.2O 0-3 MO 0-3 (M = Mg, Ca, Sr, Ba, Zn) Other 0-3
SiO.sub.2 Balance, typically 45-80
[0076] In the second type of UV absorbing glasses, these visibly
transparent glasses which are capable of being sealed with 355 nm
UV lasers are made by precipitation of CuCl microcrystals in a
glass matrix. The precipitation of CuCl in the glass is controlled
by the heat treatment, the level of Cu and Cl, the ratio of alkalis
to boron, and the redox state of the glass. These glasses possess a
very sharp UV cut-off absorption at about 370 nm and, depending on
the composition, can have absorption coefficients of over 6
mm.sup.-1 at 355 nm.
[0077] TABLE 5C illustrates an exemplary range of glass
compositions in which CuCl microcrystals can be precipitated. Glass
composition no. 29 is equivalent to Corning's Code 8511 glass, and
glass composition no. 7 is equivalent to Corning's Spectramax
product. As can be seen, the CTE of glass composition no. 29 is too
high, but it can be lowered by increasing SiO.sub.2 and lowering
Al.sub.2O.sub.3 and total alkalis
(Li.sub.2O+Na.sub.2O+K.sub.2O).
11TABLE 5C mole % comp. no. comp. comp. comp. comp. comp. comp.
comp. oxide 29 no. 30 no. 31 no. 32 no. 33 no. 34 no. 35 no. 36
SiO.sub.2 59.7 61.2 67 72.8 75.3 76.2 77.2 71.2 Al.sub.2O.sub.3
11.4 2.7 3.8 4.9 2.5 1.9 1.2 1.9 B.sub.2O.sub.3 17.2 28.4 21.5 14.5
15.8 14.3 12.8 19.5 Li.sub.2O 2 1.3 0.6 0 0 0 0 0 Na.sub.2O 4.5 5.3
5.9 6.6 5.4 5.1 4.8 7.4 K.sub.2O 3.2 0 0 0 0 0 0 0 CuO 0.4 0.3 0.4
0.4 0.4 0.4 0.4 0.31 SnO.sub.2 0.5 0.8 0.5 0.7 0.7 0.7 0.7 0.15 Br
0.25 0.5 0.25 0.5 0.5 0.5 0.5 0.4 Cl 0.06 0.75 0.06 0.75 0.75 0.75
0.75 1.4 F 0 0 0 0.75 0.75 0.75 0.75 1.3 glassy yes CTE 59 46 44 43
37 37 34 na abs., 2.9 mm-1 355 nm
[0078] In view of the data in TABLE 5C, a preferred composition
range for UV absorption CuCl microcrystal sealing glasses 106' and
106" that can be used in this embodiment of the present invention
has been determined and is listed below in TABLE 5D:
12 TABLE 5D Oxide Mole % Al.sub.2O 0-15 B.sub.2O.sub.3 10-30
Li.sub.2O 0-3 Na.sub.2O 3-8 K.sub.2O 0-4 CuO 0.2-1 SnO 0.1-1 Br
0.2-1 Cl 0-2 F 0-6 CeO.sub.2 0-3 SiO.sub.2 balance, typically
50-80%.
[0079] It should be appreciated that different types of UV
absorbing glasses like the ones shown in TABLES 5A-5D can be used
to form seals using a 355 nm pulsed laser with high repetition
rate.
[0080] In the foregoing discussion related to TABLES 3-5, 1737 or
Eagle glass was used as the transparent substrate. However, it
should be noted that if another glass, with better uv transparency,
was used as the transparent substrate, then one could use a laser
wavelength in the transparency region of that substrate glass. For
example, if high purity fused silica was used then a 266 nm laser
could be used to seal the plates.
[0081] In yet another embodiment of the present invention, any of
the aforementioned sealing glass compositions can be used in at
least one layer of a laminated glass 1302 which can be sealed to a
transparent glass 102' so as to make a glass package which is not
shown or to make a hermetically sealed OLED display 100'" as shown
in FIGURE 13. In the preferred embodiment, the laminated glass 1302
would be a two-layer glass sheet with a total thickness of
typically 1 mm or less, where one of the layers is an absorbing
glass 106' and the second layer is a clear, non-absorbing glass
1304 as viewed from the standpoint of the wavelength of the laser
110 used for sealing. In the preferred embodiment, the portion of
the laminate glass 1302 that is absorbing glass 106' would
typically be a third or less of the total thickness, giving an
absorbing layer thickness of between about 150 microns and 75
microns. The rest of the laminated sheet 1302 would be clear glass
1304.
[0082] An advantage of using the laminated sheet 1302 is that it
makes it easier to form a hermetic seal 108' from the back, i.e.
the non-TFT/OLED substrate 102' side. This is shown in FIG. 13,
where the sealing laser 110 emits a laser beam 112 through the lens
114 (optional) and at the layer of clear glass 1304 in the laminate
glass 1302 and then into the layer of absorbing glass 106', causing
the absorbing glass 106' to heat, soften, and swell to contact and
seal to the substrate glass 102'.
[0083] An advantage of the laminated concept is that less absorbing
glass 106' is required, compared to a monolithic sheet, which may
be more economical. Also, because the absorbing layer 106' is thin,
depending on the absorption coefficient, the laminated sheet 1302
can be much more transmissive in the visible wavelengths, which may
allow for "top emission" for some absorbing glasses 106' that would
not have been suitable in thicker sheets.
[0084] Following are some of the different advantages and features
of the present invention:
[0085] The hermetic seal 108' and 108" has the following
properties:
[0086] Good thermal expansion match to glass substrate plates 102',
102" and 107".
[0087] Low softening temperature.
[0088] Good chemical and water durability.
[0089] Good bonding to glass substrate plates 102', 102" and
107".
[0090] Seal is dense with very low porosity.
[0091] The doped sealing glass plate 106' can be any type of glass
that has the ability to swell. For instance, glasses that have the
ability to swell in addition to the ones listed in TABLE 1 include
Pyrex.TM. and Corning Codes 7890, 7521 or 7761. There are other
considerations in addition to having a doped sealing glass 106' and
106" that can swell which should also be taken into account in
order to form a "good" hermetic seal 108' and 108". These
considerations include having the right match between the CTEs and
the viscosities of the sealed glasses. It should be noted that
residual stress measurements have indicated that it is preferable
to have the CTE of the sealing glass 106' and 106" the same as or
lower than the CTE of the substrate glass 102', 102" and 107".
Other considerations to achieve a "good" hermetic seal 108' and
108" include choosing the right conditions such as laser power,
focusing and velocity of sealing.
[0092] It is important to understand that other types of substrate
plates 102" and 107" besides the Code 1737 glass plates and EAGLE
2000.TM. glass plates can be sealed to one another using the
sealing process of the present invention. For example, glass plates
102" and 107" made by companies such as Asahi Glass Co. (e.g., OA10
glass and OA21 glass), Nippon Electric Glass Co., NHTechno and
Samsung Corning Precision Glass Co. can be sealed to one another
using the sealing process of the present invention.
[0093] The OLED display 100 can be an active OLED display 100 or a
passive OLED display 100.
[0094] The sealing glass plate and sealing glass fiber of the
present invention can be designed to absorb heat in other regions
besides the infrared region described above.
[0095] Although several embodiments of the present invention has
been illustrated in the accompanying Drawings and described in the
foregoing Detailed Description, it should be understood that the
invention is not limited to the embodiments disclosed, but is
capable of numerous rearrangements, modifications and substitutions
without departing from the spirit of the invention as set forth and
defined by the following claims.
* * * * *