Electric lamp or space discharge component or device manufacturi – Process – Electrode making
Reexamination Certificate
2002-03-12
2004-12-28
Williams, Joseph (Department: 2879)
Electric lamp or space discharge component or device manufacturi
Process
Electrode making
C445S049000
Reexamination Certificate
active
06835112
ABSTRACT:
FIELD OF THE INVENTION
Recently, multifunction and diversification of an electronic apparatus (particularly a portable terminal device, e.g., a cellular phone) have progressed, so that electroluminescent lamp (EL lamp) is used for illuminating a display area or an operating section of the apparatus.
BACKGROUND OF THE INVENTION
A conventional electroluminescent lamp (EL lamp) will be described with reference to FIG.
6
.
FIG. 6
shows a sectional view of the conventional EL lamp. As shown in
FIG. 6
, light-transmitting electrode-layer
52
, e.g., indium tin oxide, is formed on a whole surface of transparent substrate
51
, e.g., a glass or a film, using a sputtering method or an electron beam method.
The conventional EL lamp is formed by the following elements:
(a) luminescent layer
53
formed of the synthetic resin layer
53
A in which phosphor particles
53
B, e.g., zinc sulfide, (base material of luminescence) disperse, and formed on transparent substrate
51
,
(b) dielectric layer
54
made of synthetic resin, where barium titanate disperses, and formed on luminescent layer
53
,
(c) back electrode-layer
55
made of silver or carbon resin, and formed on dielectric layer
54
, and
(d) insulating layer
56
made of epoxy resin or polyester resin and formed on back electrode-layer
55
.
The EL lamp mentioned above is installed in an electronic apparatus, and an AC voltage is applied between light-transmitting electrode-layer
52
and back electrode-layer
55
. As a result, phosphor particle
53
B of luminescent layer
53
emits light, and the light illuminates a display area or an operating section of the electronic apparatus from behind.
Luminescent layer
53
is formed by the following method. First, paste is made of cyano resin or fluororubber dissolved in organic solvent. Second, phosphor particles
53
B disperse in the paste. Third, the paste is formed by a reverse-roll coater or a die coater, or printed by a screen printing. Finally, the paste is dried and formed. By the coating method using the reverse-roll coater or the die coater, phosphor particles
53
B can be dispersed in luminescent layer
53
uniformly to a certain extent by changing composition of phosphor particles
53
B in the paste or thickness of the coating paste. By this coating method, the luminescent layer can coat on the whole surface of a rectangular substrate, however, can not coat the surface in a specific pattern.
When the specific pattern is required, the screen printing is usually used for forming luminescent layer
53
. A screen mask used for the screen printing is made of sheet which is formed by knitting stainless threads or polyester threads of diameter approximately 30 &mgr;m. The sheet is formed of opening-sections into which paste penetrates and closed-sections into which paste does not penetrate, so that a pattern of an electrode can be printed. As shown in
FIG. 6
, because the sheet is formed by knitting threads, area
53
C under the threads or under intersections of the threads printed with phosphor particles
53
B insufficiently or not printed tends to occur.
A mean diameter of phosphor particles
53
B is approximately 20 &mgr;m through 25 &mgr;m. As shown in
FIG. 6
, when phosphor particles
53
B are printed using a screen mask of thickness 60 &mgr;m, two or three of phosphor particles
53
B tends to pile up at an area
53
D under the opening-section.
In the conventional EL lamp discussed above, phosphor particles
53
B are difficult to disperse in luminescent layer
53
uniformly, so that an area on which phosphor particles
53
B do not disperse or pile up tends to occur. As a result, light emission from phosphor particles
53
B tends to produce uneven brightness.
When luminescent layer
53
is formed of paste, which is made of synthetic resin dissolved in organic solvent, and phosphor particles
53
B disperse in the resin, a state of dispersing phosphor particles
53
B tends to disperse unevenly even in the same printing condition. Because characteristics of printing is changed by diameters or shapes of phosphor particles
53
B, or changed by a surface shape of light-transmitting electrode-layer
52
.
SUMMARY OF THE INVENTION
The present invention addresses the problem discussed above, and aims to provide an electroluminescent lamp (EL lamp), of which brightness uniformity is improved, and provide a method for manufacturing the EL lamp.
The EL lamp of this invention includes the following elements:
(a) a transparent substrate,
(b) a light-transmitting electrode-layer formed on the transparent substrate,
(c) an adhesive synthetic resin layer formed on the light-transmitting electrode-layer,
(d) a luminescent layer which is formed of the synthetic resin layer with phosphor particles dispersed uniformly,
(e) a dielectric layer formed on the luminescent layer,
(d) a back electrode-layer formed on the dielectric layer.
Each phosphor particle disperses on the synthetic resin layer uniformly, and the luminescent layer is thus formed, so that the EL lamp having improved brightness uniformity is obtainable. Because a voltage is applied to the luminescent layer uniformly, an inexpensive and uniform EL lamp with high brightness using less phosphor particles is obtainable.
The method for manufacturing the EL lamp includes the following steps:
(a) forming a light-transmitting electrode-layer on a transparent substrate,
(b) forming an adhesive synthetic resin layer on the light-transmitting electrode-layer,
(c) sticking phosphor particles on the synthetic resin layer uniformly so that a luminescent layer is formed,
(d) forming a dielectric layer on the luminescent layer, and
(e) forming a back electrode-layer on the dielectric layer.
As a result, an inexpensive and uniform EL lamp having improved brightness can be produced.
REFERENCES:
patent: 4289799 (1981-09-01), Sarvas
patent: 4902567 (1990-02-01), Eilersten et al.
patent: 5598067 (1997-01-01), Vincent et al.
patent: 0 323 218 (1989-07-01), None
patent: 4-36993 (1992-02-01), None
patent: 8-148278 (1996-10-01), None
patent: 2001-284053 (2001-10-01), None
patent: WO 88/04467 (1988-06-01), None
patent: WO 00/42825 (2000-07-01), None
Chikahisa Yosuke
Kawasumi Akito
Nishioka Naohiro
Okuma Shinji
Tanabe Koji
McDermott Will & Emery LLP
Williams Joseph
LandOfFree
Electroluminescent lamp and method for manufacturing the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electroluminescent lamp and method for manufacturing the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electroluminescent lamp and method for manufacturing the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3310115