Illumination – Revolving
Reexamination Certificate
2001-12-14
2004-04-06
Quach-Lee, Y. My (Department: 2875)
Illumination
Revolving
C362S027000
Reexamination Certificate
active
06715896
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a frame unit of a spread illuminating apparatus used as an illuminating means for a reflection-type display.
2. Description of the Related Art
A liquid crystal display featuring low profile, small occupied volume and light weight is used for many electrical products such as mobile phones and personal computers, and the demand thereof has been increased. Since a liquid crystal which is a component of the liquid crystal display does not emit light by itself, an illuminating means for a liquid crystal is separately required besides the liquid crystal display when used in dark places where solar or room light is not satisfactorily available. Thus, this illuminating means is desired to be compact in size and small in power consumption. In recent years, a thin plate-like spread illuminating apparatus of side light type (light conductive member type) is often applied in the liquid crystal display.
FIG. 9
shows an embodiment of a conventional spread illuminating apparatus of side light type.
As shown in the figure, a spread illuminating apparatus
1
′ is generally composed of a transparent substrate
2
made of a light-transmissible material and a bar-like light source
5
disposed close to an end surface
8
of the transparent substrate
2
. Light rays emitted from the light source
5
are introduced into the transparent substrate
2
, and then reflected to illuminate a liquid crystal display (not shown) disposed under the transparent substrate
2
.
The light source
5
is composed of a bar-like light conductive member
3
made of a transparent material and a spot-like light source (e.g. a light-emitting diode)
4
disposed facing one end of the light conductive member
3
. The light conductive member
3
is provided with an optical path conversion means
12
. The optical path conversion means
12
, which makes light rays emitted from the spot-like light source
4
incident uniformly onto the end surface
8
of the transparent substrate
2
, has grooves triangular in section on a surface opposite to a surface
9
facing the end surface
8
of the transparent substrate
2
. The light conductive member
3
is disposed with the surface
9
running along the end surface
8
of the transparent substrate
2
at a predetermined distance therefrom.
The thickness of the transparent substrate
2
gradually decreases with the increase in distance from the end surface
8
, forming the section of the transparent substrate
2
into a wedge-shape. A light reflection pattern
59
is formed on an upper surface
65
of the transparent substrate
2
. The light reflection pattern
59
comprises grooves
57
triangular in section and flat portions
58
adjacent thereto, both formed parallel to the light conductive member
3
with predetermined intervals between each other. The grooves
57
are formed to vary in depth from each other so that light coming from the light conductive member
3
is reflected in a substantially uniform manner at a whole surface of the transparent substrate
2
irrespective of the distance from the light conductive member
3
(the light source
5
) thereby uniformly illuminating the liquid crystal display (not shown) provided under the transparent substrate
2
. Namely, the depth of the grooves
57
increases gradually in proportion to the increase in distance from the light conductive member
3
.
A light reflection member (frame)
13
is provided so as to cover the light conductive member
3
for efficiently guiding light rays emitted from the spot-like light source
4
into the transparent substrate
2
, protecting the light conductive member
3
against damages due to contact with other components, and preventing the light conductive member
3
from getting dust. The frame
13
is formed by bending in an approximately U-shape and is attached in such a manner as to cover longitudinal peripheral surfaces of the light conductive member
3
except the surface
9
facing the transparent substrate
2
. Further, upper and lower opposing plates
13
e
,
13
f
of the frame
13
are inclined inwardly so as to have a predetermined angle from a direction perpendicular to a base plate
13
g
of the frame
13
. When the frame
13
is set, the frame
13
is disposed in such a manner that distal ends of the upper and lower opposing plates
13
e
,
13
f
(ends opposite to ends continuous with the base plate
13
g
) cover the ends of the upper and lower surfaces
65
,
66
, respectively. Since the upper and lower opposing plates
13
e
,
13
f
are inclined inwardly giving an elastic force, the frame
13
is adapted to clamp the transparent substrate
2
and thereby fixed thereto. The frame
13
is structured such that a hard resin product has on the inner surface thereof a film on which a metal such as silver is evaporated or a white film or that a metal plate of aluminum or stainless is bent.
The frame
13
may be fixed to the transparent substrate
2
by placing a double-faced adhesive tape
54
on either of their overlapping portions, for instance, at the ends of the upper and lower surfaces
65
,
66
of the transparent substrate
2
.
However, the above conventional art has the following problems.
In the method of fixing the frame to the substrate by means of its elastic force, since fixing force between components (transparent substrate, light conductive member, and spot-like light source) is weak resulting in the components getting easily out of position, a stable illumination effect may not be achieved. Further, since the weak fixing force makes it difficult to connect or assemble the frame with other components (e.g. a liquid crystal display and so on), and since the assembly work must be carried out carefully so that the frame does not contact with the transparent substrate or the light conductive member, the working efficiency deteriorates.
In the method using an adhesive tape, the overall thickness of the apparatus increases for the thickness of the adhesive tape, and an irregularity in surface exists at the edges the adhesive tape.
Moreover, the frame covers only the light conductive member and does not protect the spread illuminating apparatus entirely.
SUMMARY OF THE INVENTION
The present invention has been made in light of the above problems and the object of the present invention is to provide a spread illuminating apparatus which includes a frame unit capable of securely fixing its components thereby achieving a stable illumination effect.
In order to solve the problems, according to a first aspect of the present invention, in a spread illuminating apparatus comprising: a spread illuminating section in which a bar-like light source composed of a light conductive member and a spot-like light source disposed at an end of the light conductive member is provided close to and along one end surface or each of two end surfaces of a transparent substrate made of a light-transmissible material; and a frame unit, the frame unit covers peripheral portions of upper and lower surfaces of the spread illuminating section and surfaces of both ends of the spread illuminating section, at least one of which the bar-like light source constitutes. Here, the spread illuminating section means a part of a spread illuminating apparatus and is composed of a transparent substrate and at least one light source disposed on an end surface thereof (and a light reflection member if provided).
According to a second aspect of the present invention, in the spread illuminating apparatus described in the first aspect, the frame unit is composed of two frame sub-assemblies, which are fitted onto the spread illuminating section from respective ends of the spread illuminating section, and are coupled to each other. With this construction, the entire periphery of the spread illuminating section can be covered with the frame unit and thus the components constituting the spread illuminating section can be fixed reliably.
According to a third aspect of the present invention, in the spread illuminating apparatus described in th
Kawashima Satoshi
Nishioka Akihisa
Minebea Co. Ltd.
Quach-Lee Y. My
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