Illumination – Revolving
Reexamination Certificate
2001-01-26
2002-04-30
Spyrou, Cassandra (Department: 2872)
Illumination
Revolving
C362S026000, C349S063000
Reexamination Certificate
active
06379017
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an illuminating system to be used for printed articles such as books and photographs, screen displays of personal computers or other office automation equipment, portable information terminals, portable video tape recorders and the like, or reflection type liquid crystal displays used in various monitors, and the like.
In recent years, personal computers, portable information terminals, video tape recorders and the like have been becoming increasingly small-sized and portable, making it an important issue to reduce the power consumption of their image display units. On this account, many of them have been provided with reflection type liquid crystal displays used as their image display units.
The reflection type liquid crystal display device is given screen brightness by reflecting outside light such as sunlight and indoor light. However, at places of less outside light, the device could not afford enough brightness in the screen. As a result of this, there have been invented several reflection type liquid crystal displays equipped with an illuminating system which enables screen display even at places of insufficient outside light.
An example of the illuminating system to be mounted on the reflection type liquid crystal display device is shown.
FIG. 16
is a schematic cross-sectional view of a conventional illuminating system. As shown in
FIG. 16
, the conventional illuminating system comprises a light source
1
, a reflector
2
, a light guide member
63
and a compensating plate
5
. In order that the reflector
2
collimates the light emitted from the light source
1
, the distance from the light source
1
to a side face of the light guide member
63
is elongated. The light guide member
63
has a function of propagating the light introduced from the reflector
2
by totally reflecting the light, and a function of illuminating a reflecting plate
4
by totally reflecting the light with slopes of grooves formed in its top face to change the angle of the light. The compensating plate
5
has a function of correcting any distortion that occurs when the reflected light from the reflecting plate
4
passes the light guide member
63
.
However, in the conventional illuminating system, when the light that has been transmitted by the light guide member
63
to the compensating plate
5
comes incident on the light guide member
63
again after being totally reflected by the top face of the compensating plate
5
, part of the light is reflected by the slopes of the grooves of the top face of the light guide member
63
so that groove lines are more visible, as an issue. Also, whereas light is collimated by a reflector to reduce the issue of these groove lines' visibility, the collimated light is more likely to reach one side of the light guide member
63
opposite to the light source without impinging on the slopes of the grooves of the light guide member
63
. This would result in a low illuminating efficiency, as another issue.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide an illuminating system which makes groove lines less visible, maintains an image of reflected light successful and offers a good illuminating efficiency.
In accomplishing these and other aspects, according to a first aspect of the present invention, there is provided an illuminating system comprising:
a light source; and
a transparent plate with the light source placed beside a side face thereof,
wherein a plurality of grooves filled with a layer having a refractive index different from a refractive index of the transparent plate are arranged at specified intervals in a surface or interior of the transparent plate.
According to a second aspect of the present invention, there is provided an illuminating system according to the first aspect, wherein a top face and a bottom face of the transparent plate are generally parallel to each other.
According to a third aspect of the present invention, there is provided an illuminating system according to the first or second aspect, wherein a condition of
&thgr;<sin
−1
(
n
1
)−sin
−1
{(1
)sin(&bgr;)}
is satisfied where n is the refractive index of the transparent plate, n
1
is the refractive index of a material as the layer that fills the grooves which are the slits, &thgr; is an angle formed by each of the slits and the top face of the transparent plate and &bgr; is an angle of visibility of the illuminating system.
According to a fourth aspect of the present invention, there is provided an illuminating system comprising:
a light source;
a transparent first plate with the light source placed beside a side face thereof; and
a transparent second plate placed on a top face of the first plate,
wherein a bottom face of the first plate is a plane surface and a plurality of stepwise slopes are arranged at specified intervals in the top face of the first plate;
in a bottom face of the second plate, stepwise slopes are arranged so as to be identical in configuration to the slopes of the top face of the first plate; and
the top face of the first plate and the bottom face of the second plate are placed with a specified spacing.
According to a fifth aspect of the present invention, there is provided an illuminating system according to the fourth aspect, wherein a condition of
&thgr;<sin
−1
(
n
2
)−sin
−1
{(1
)sin(&bgr;)}
is satisfied where n is the refractive index of the first plate, n
2
is the refractive index of a material as the layer bonding the first plate and the second plate to each other, &thgr; is an angle of each of the slopes of the top face of the first plate and the bottom face of the second plate and &bgr; is an angle of visibility of the illuminating system.
According to a sixth aspect of the present invention, there is provided an illuminating system according to the fifth aspect, wherein a light outgoing angle of a collimator placed at an outgoing exit of the light source is within ±sin
−1
[nxsin{90−&thgr;−sin
−1
(n
2
)}].
According to a seventh aspect of the present invention, there is provided an illuminating system by overhead irradiation comprising:
a light source;
a transparent plate which is a light guide member in which a plurality of grooves are arranged in a top face of the light guide member at specified intervals in a direction parallel to a longitudinal direction of the light source, and in which a flat portion constituting a part of the top face is arranged between adjacent ones of the grooves, wherein an illumination object placed on a bottom face side of the light guide member is observed from a top face side of the light guide member.
According to an eighth aspect of the present invention, there is provided an illuminating system by overhead irradiation according to the seventh aspect, wherein each of the grooves of the light guide member is a V-shaped groove having a first slope located on one side closer to the light source and a second slope located on the other side farther from the light source, and wherein an angle &thgr;
1
formed by the first slope and the bottom face of the light guide member falls within a range of &thgr;
1
≦90°−&thgr;
c
+2&thgr;
3
, where &thgr;
c
is a total reflection angle of the light guide member and &thgr;
3
is an angle formed by the flat portion and the bottom face of the light guide member.
According to a ninth aspect of the present invention, there is provided an illuminating system by overhead irradiation according to the seventh or eighth aspect, wherein each of the grooves of the light guide member is a V-shaped groove having a first slope located on one side closer to the light source and a second slope located on the other side farther from the light source, and wherein an angle &thgr;
1
formed by the first slope and the bottom face of the light guide member satisfies a condition of:
&thgr;
1
≈45+&thgr;
3
−(1/2)sin
−1
(1
xsin&bgr;), where
Fukui Atsushi
Nakabayashi Koki
Nishii Kanji
Tatsuta Ken
Watanabe Hiroshi
Matsushita Electric - Industrial Co., Ltd.
Spyrou Cassandra
Wenderoth , Lind & Ponack, L.L.P.
Winstedt Jennifer
LandOfFree
Illuminating system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Illuminating system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Illuminating system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2864683