Electric lamp or space discharge component or device manufacturi – Process – With assembly or disassembly
Reexamination Certificate
2001-07-12
2003-03-18
Ramsey, Kenneth J. (Department: 2879)
Electric lamp or space discharge component or device manufacturi
Process
With assembly or disassembly
C445S022000
Reexamination Certificate
active
06533633
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an aperture fluorescent lamp manufacturing method, which is suitably used for manufacturing a relatively small-diameter aperture fluorescent lamp having an aperture portion opened for light projection in a part of a straight glass tube in the axial direction, a manufacturing method of a surface illuminator provided with an aperture fluorescent lamp, a relatively small-diameter aperture fluorescent lamp, a surface illuminator provided with an aperture fluorescent lamp, a liquid crystal display device provided with the surface illuminator, and an electronic device provided with the liquid crystal display device.
The present application claims priority of Japanese Patent Application No.2000-215239 filed on Jul. 14, 2000, which is hereby incorporated by reference.
2. Description of the Related Art
Conventionally, an aperture fluorescent lamp has been available, which emits light in a concentrated manner from an opening portion (referred to as an aperture portion, hereinafter) for light projection provided in a part of a straight glass tube in the axial direction. This aperture fluorescent lamp has widely been used as a backlight source, for example, in a liquid crystal display device for OA (Office Automation) equipment. The aperture fluorescent lamp has also been used as a document illumination light source in a facsimile, a copying machine, or the like.
With regard to a method for manufacturing such an aperture fluorescent lamp, technologies that have been available include, for example, one disclosed in Japanese Patent Laid-open No. Hei 6-260088 for forming an aperture portion by using a method of scraping off a phosphor with a rod (referred to as a first conventional technology), and one disclosed in Japanese Patent Laid-open No. Hei 9-306427 for forming an aperture portion with a photo mask (referred to as a second conventional technology).
In the case of the first conventional technology, as shown in
FIG. 30
, first, a phosphor is coated on the inner surface of a cylindrical glass tube
101
having both ends opened to form a phosphor layer
102
. Then, a metal rod
104
having a brush
103
on a tip portion containing a magnetic substance like that shown in
FIG. 31
is inserted from one opening of the glass tube
101
as shown in
FIG. 32
, and guided by a magnet
105
from the outside of the glass tube
101
. The brush
103
is moved in pressed state to the phosphor layer
102
to scrape off the phosphor in a predetermined region, thus forming an aperture portion
106
as shown in FIG.
33
.
In the case of the second conventional technology, first, a mixture of a photo-curing resin and a phosphor is coated inside a glass tube. Then, a photo mask (not shown) is attached to a predetermined region, in which an aperture portion
106
is formed, and irradiated with ultraviolet rays. Then, the photo mask is removed, an insensitive portion is washed off with hot pure water, and then dried and subjected to heating and burning. Then, a phosphor layer
102
is formed on other than the aperture portion
106
as shown in FIG.
33
.
In addition, in both ends of an aperture fluorescent lamp
107
manufactured in the foregoing manner, as shown in
FIG. 34
, positioning pieces
108
for aligning an orientation of the aperture portion
106
at backlight assembly are attached.
To manufacture, for example, a backlight
115
of a sidelight type, by using the aperture fluorescent lamp
107
having such positioning pieces, as shown in
FIGS. 35 and 36
, by fitting each of the positioning pieces
108
in a groove of a reflector
109
groove-shaped in section for reflecting and guiding light emitted from the aperture fluorescent lamp
107
to a light guide plate
112
, the aperture fluorescent lamp
107
is attached to the reflector
109
. Then, the reflector
109
having the aperture fluorescent lamp
107
attached thereto is fixed onto a rear case
110
. At this time, the aperture portion
106
is positioned to face a direction (horizontal direction in
FIGS. 35 and 36
) roughly parallel to the top surface of the rear case
110
as a casing.
On the rear case
110
, a reflection sheet
111
, the light guide plate
112
, and an optical correction sheet
113
are sequentially laminated, and then covered with a center case
114
, thus completing the backlight
115
.
To manufacture a directly-below backlight
116
of a directly-below type by using aperture fluorescent lamps
107
, as shown in
FIG. 37B
, a plurality of aperture fluorescent lamps
107
,
107
. . . , are positioned and disposed on the bottom part of a reflection plate
117
such that the aperture portions
106
can face a direction (directly above in the drawing) vertical to a light emission surface. Above the aperture fluorescent lamps
107
,
107
. . . , a diffusion plate
118
is attached for obtaining a surface light source by diffusing emitted or reflected light.
With regard to the method for manufacturing the aperture fluorescent lamp, in the case of the first conventional technology, to manufacture a relatively small-diameter aperture fluorescent lamp, the brush
103
and the metal rod
104
must be formed thin. However, if the metal rod
104
is formed thin, the metal rod
104
is fluttered or bent, damaging the phosphor layer
102
other than the aperture portion
106
. Consequently, it is practically difficult to manufacture a small-diameter aperture fluorescent lamp having an inner diameter of 3 mm or less.
In addition, to manufacture an aperture fluorescent lamp having a long glass tube length, length of the metal rod
104
must be made long. Thus, the metal rod
104
is fluttered or bent, damaging the phosphor layer
102
other than the aperture portion
106
. Consequently, it is also difficult to manufacture an aperture fluorescent lamp having the long glass tube length.
Therefore, in the backlight as a surface illuminator using the aperture fluorescent lamp manufactured by the foregoing method, for example, as shown in
FIG. 36
, the size of a housing part
109
h
(
FIG. 36
) of the aperture fluorescent lamp
107
, which is formed by being surrounded with the rear case
110
, cannot be reduced. In other words, a longitudinal width a
0
including clearances b
0
and c
0
in upper and lower sides of the aperture fluorescent lamp
107
and a transverse width d
0
cannot be reduced. In addition, a width e
0
, which is regulated by the transverse width d
0
, of a frame part of the center case
114
above the aperture fluorescent lamp
107
cannot be reduced. Consequently, it is impossible to reduce not only weight of the aperture fluorescent lamp
107
but also those of other members.
It can therefore be understood that there are difficulties of thinning, narrow frame formation, and weight reduction for the backlight using the aperture fluorescent lamp manufactured by the described manufacturing method.
Thus, there are also difficulties of thinning, narrow frame formation, and weight reduction for both of a liquid crystal display device using the backlight and an electronic device using such the liquid crystal display device.
In the case of the second conventional technology, in addition to mixture coating step, exposure, developing, and many other steps are necessary. Thus, much time, and labor must be expended, thereby causing an increase in cost.
Therefore, there are problems of high costs for the backlight
115
as a surface illuminator using the aperture fluorescent lamp
107
manufactured by the described manufacturing method, a liquid crystal display device using the backlight
115
, and a device using such the liquid crystal display device.
In the foregoing positioning method of the aperture portion
106
, the positioning pieces
108
as members dedicated for positioning are necessary in the manufacturing process of the aperture fluorescent lamp
107
.
Thus, material and process costs are increased by attaching (adhering) of the positioning pieces
108
, and there are difficulties of thinning, narrow frame formation, and weight
McGinn & Gibb PLLC
NEC Corporation
Ramsey Kenneth J.
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