Boots – shoes – and leggings – Soles – Sectional
Reexamination Certificate
2000-02-22
2002-07-09
Sember, Thomas M. (Department: 2875)
Boots, shoes, and leggings
Soles
Sectional
C362S026000, C362S800000, C362S328000, C362S330000, C362S235000
Reexamination Certificate
active
06415531
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a plane-shaped lighting device of the edge-light system and a display device using such a device. The plane-shaped lighting device is used as a backlight for, for example, liquid crystal displays and other displays, such as advertising boards, guiding boards and traffic signs that are placed inside or outside buildings.
BACKGROUND OF THE INVENTION
Conventionally, displays of the back-lighting type have been widely used as advertising signs and road-traffic signs in order to make them discernible at night or in order to improve visibility of the contents of the displays such as characters and diagrams. In these displays, patterned display boards, having the contents of displays, are made with a light-transmitting or semi-light-transmitting property, and the information of the displays is visually displayed by illuminating the patterned display boards from behind. Plane-shaped lighting devices, which are used as back lights for such displays, are mainly classified into two systems, the edge-light system and the direct underlight system.
For example, as illustrated in
FIG. 50
, a plane-type lighting device of the edge-light system, which is placed on the back of a patterned display board in parallel therewith, has a light-directing plate
1
made of a plate-shape light-transmitting member and a light source
2
that is placed at a light-incident surface
1
a
that forms one side end of the light-directing plate
1
. Light, released from the light source
2
, is made to be incident on the light-incident surface
1
a
of the light-directing plate
1
. Then, the light, which has proceeded inside the light-directing plate
1
after repeating total reflections, is taken out ahead of a plane section
3
by a light-takeoff body
4
that is provided on the rear surface
3
b
or the front surface
3
a
of the plane section
3
, and made to be incident on the patterned display board. In contrast, in a plane-type lighting device of the direct-under system, a rod-shaped light source such as a fluorescent lamp is placed on the back of a patterned display board so as to directly illuminate the patterned display board. Here, since the direct-under system needs to have more thickness than the edge-light system, the edge-light system has been widely used for plate-shaped lighting devices that require thin structures.
The following description will discuss the plane-shaped lighting device of the edge-light system. The light-directing plate
1
is made of, for example, a light-transmitting material such as acryl, and the light source
2
is constituted of, for example, rod-shaped or array-shaped light sources such as fluorescent lamps or LED lamps. Further, as illustrated in FIGS.
51
(
a
) and
51
(
b
), light-takeoff bodies
4
are formed on the front surface
3
a
or the rear surface
3
b
of the plane section
3
of the light-directing plate
1
so as to form, for example, a dot-patterned or circle-patterned scattering surface. The density of the light-takeoff bodies
4
increases as they are located apart from the light source
2
. The light-takeoff bodies are provided as scattering print surfaces
4
A that have been formed by using white-based ink or other materials by a screen printing method or other methods, as shown in FIG.
51
(
a
), or provided as rough surfaces
4
B that have been formed by roughening the surface of the light-directing plate
1
by using the blast treatment or other treatments, as shown in FIG.
51
(
b
). Thus, light that has been made to be incident on these bodies is allowed to scatter in all directions, and is taken out from the light-directing plate
1
.
Moreover, a reflection plate
5
is placed on the rear surface
3
b
of the plane section
3
so as to keep the scattered light from going out in the rear-surface
3
b
direction. Furthermore, for example, reflection layers, (not shown), made of materials such as reflective tapes and white ink, are disposed on the side faces
1
b,
1
c
and
1
d
other than the light-incident surface
1
a
of the light-directing plate
1
so that the light that has proceeded inside the light-directing plate
1
without having been taken out from the plane section
3
of the light-directing plate
1
is again returned into the light-directing plate
1
.
FIG. 52
shows another prior art example of a plate-shaped lighting device. The structure of this plate-shaped lighting device, which is similar to that illustrated in
FIG. 51
, is provided with light-takeoff bodies
4
, each of which has either a solid-line shape or a broken-line shape and is formed on the rear surface
3
b
of the plane section
3
of the light-directing plate
1
, as shown in FIG.
53
. The light-takeoff bodies
4
, which form a plurality of line-shaped grooves
4
C parallel to the light-incident surface
1
a,
have their density increased as they are located apart from the light source
2
. The grooves
4
C are formed into a V-letter shape by machining the rear surface
3
b
of the light-directing plate
1
by the use of, for example, a dicing method or an etching method. Here, the light that has been made to be incident on each groove
4
C is reflected toward the plane section
3
, and taken out from the plane section
3
through a scattering sheet
6
.
In the plane-shaped lighting devices of the edge-light system using the light-directing plate
1
, LED lamps
7
have been used as the light source particularly in order to provide low power consumption and maintenance-free operation. As illustrated in
FIG. 54
, a plurality of LED lamps
7
, which forms a light source
2
, are arranged in an array on a substrate
8
in a manner opposing the light-incident surface
1
a
of the light-directing plate
1
. As illustrated in FIGS.
55
(
a
) and
55
(
b
), in each LED lamp
7
, a lead frame
11
with a reflection cup
10
inside of which an LED chip
12
is installed, and the LED chip
12
is molded with a light-transmitting resin
13
. Further, a semispherical lens
15
is formed at one portion of a box-like body
14
, and the LED lamps are classified into two types, that is, the scattering type and the transparent type, depending on the types of molding resins that constitute the box-like body
14
.
In the LED lamp
7
of the scattering type, shown in FIG.
55
(
a
), since it is molded with light-transmitting resin
13
to which filler is added, light emitted from the LED chip
12
is scattered by the filler inside the resin
13
, and transmitted in all directions. In contrast, the LED lamp
7
of the transparent type, shown in FIG.
55
(
b
), is formed by using transparent resin as the molding resin
13
and is normally designed as a high-luminance lamp. Further, in order to converge light in the light-axis direction, the distance Z from the LED chip
12
to the top of the semispherical lens
15
is set to be 1.8 to 2.1 times as long as the radius of curvature of the semispherical lens
15
.
The use of the plate-shaped lighting devices of the edge-light system has made display devices thinner. In such display devices of the back-lighting type, a patterned display board, which displays information such as diagrams and characters, has a construction wherein its pattern is displayed by changing transmitting colors and transmittances through character portions and their surrounding portions. Further, in some specific cases of such a construction, the transmittance of either the character portions or the surrounding portions is set to zero, and the character portions or their peripheral portions are subjected to a cut-out process so that predetermined light-transmitting color filters can be provided at the portions that transmit light.
Japanese Laid-Open Patent Publication No. 85588/1992 (Tokukaihei 4-85588) has disclosed one of such displays wherein the character portions are subjected to the cut-out process and color filters are provided at the cut-out portions. As illustrated in
FIG. 56
, LEDs
21
, which serve as a light source, are arranged in series with one another on a side-end face
20
c
of a light-di
Azuma Hitoshi
Funakoshi Takahiro
Kimoto Masahiko
Minematsu Hiroshi
Ohtsuki Terukazu
Sember Thomas M.
Sharp Kabushiki Kaisha
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