Illumination – With control console
Reexamination Certificate
2002-04-09
2003-09-30
O'Shea, Sandra (Department: 2875)
Illumination
With control console
C362S561000, C362S035000
Reexamination Certificate
active
06626552
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mobile information terminal having a cover which serves also as a liquid crystal display device.
2. Description of the Related Art
Recently, as typified by a notebook-type personal computer, a mobile information terminal which uses an electric power charged in an internal battery so as to be operable without using a power cord and portable is becoming pervasive. In many mobile information terminals, mounted is a transmission liquid crystal display device which uses light emitted from a backlight. In order to improve the portability of a mobile information terminal, a battery is requested to have a long life period, and also to be light in weight.
FIG. 7
is a side view of a notebook-type personal computer of the conventional art. The notebook-type personal computer
1
has a configuration in which a cover
3
is connected to the main unit
2
via an axis
4
so that the cover
3
is movable.
First, the main unit
2
has a processing unit (not shown) such as a CPU, and a controlling unit (not shown) in a case. An input device
5
such as a keyboard is disposed on the surface of the main unit. The axis
4
for connecting the cover
3
is placed in one end portion of the main unit
2
.
Next, the cover
3
is connected to the main unit
2
via the axis
4
disposed in an end portion
13
, and has a liquid crystal display device
8
disposed in an outer case
12
. The liquid crystal display device
8
is configured by a liquid crystal panel
14
and a backlight
15
. The display screen of the liquid crystal panel
14
is exposed from the outer case
12
so as to be seen. The backlight
15
is placed on the rear face of the liquid crystal panel
14
to illuminate the liquid crystal panel
14
from the rear side. The liquid crystal panel
14
controls the transmission of the light of the backlight
15
to display an image. The backlight
15
is exposed from the outer case
12
so that the exposed portion functions as a light-introducing portion
30
. The light-introducing portion
30
introduces external light such as sunlight or roomlight. The introduced external light can be used as light with which the backlight
15
illuminates the liquid crystal panel
14
. The main unit
2
and the cover
3
are provided with a lock mechanism
6
. The lock mechanism
6
is configured by a knob portion
6
a,
a hook portion
6
b,
and a hook hole so as to fix the main unit
2
and the cover
3
together when the cover
3
is closed. When the knob portion
6
a
is moved toward an end portion
9
, the hook portion
6
b
is moved to be disengaged from the hook hole which is formed in a position of the cover
3
corresponding to the hook portion
6
b,
thereby allowing the cover
3
to be opened.
Next, the liquid crystal display device
8
will be described in detail.
FIG. 8
is a section view of the cover
3
. The liquid crystal display device
8
is positioned in the outer case
12
, and configured by the liquid crystal panel
14
and the backlight
15
. The liquid crystal panel
14
has a configuration in which a liquid crystal layer
21
is interposed between two substrates
23
made of a transparent insulative material such as glass. A polarizing plate
22
is disposed on the outside of each of the substrates
23
. The polarizing plates
22
are placed so that their polarizing axes are perpendicular or parallel to each other. In the liquid crystal layer
21
, the initial alignment of liquid crystal molecules (not shown) is determined by an alignment film. A voltage is applied across transparent electrodes (not shown) on the glass substrates
23
to change the alignment of the liquid crystal molecules in the liquid crystal layer
21
, whereby the light transmittance is changed. As a result, the liquid crystal panel
14
can display an image.
The backlight
15
is configured by a light guide plate
26
, a light source
27
, a reflector plate
28
, a diffusion plate
29
, and a lens sheet (not shown). The light source
27
is a light source consisting of, for example, a cold cathode tube. The light guide plate
26
is made of a transparent resin such as an acrylic resin, and guides light emitted from the light source
27
. An end portion of the light guide plate
26
which is opposed to the light source
27
is formed as the light-introducing portion
30
which is exposed from the outer case
12
. The light-introducing portion
30
introduces external light such as sunlight or roomlight into the light guide plate
26
. The light introduced into the light-introducing portion
30
is used as a light source in place of or auxiliary to the light source
27
, so that it is reflected by the reflector plate
28
in the direction to the diffusion plate
29
, formed into a surface light source by the diffusion plate
29
, converged by the lens sheet (not shown), and then emitted from an illumination surface of the light guide plate
26
to impinge on the liquid crystal panel
14
. When the external light is used as a light source in place of the light source
27
, the power consumption of the light source
27
can be reduced. When the external light is used as a light source auxiliary to the light source
27
, the brightness of the liquid crystal panel
14
can be enhanced so that the visibility of the liquid crystal panel
14
can be improved.
In the transmission liquid crystal display device which uses only the internal light source
27
, the power consumed by the light source
27
amounts to 60 to 70% of the power consumption of the liquid crystal display device. As a result, the life period of the battery which supplies the power to the mobile information terminal is shortened, and hence the mobile information terminal cannot be carried for a long time period. When the size of a battery pack is increased in order to prolong the life period of the battery, the weight of the whole mobile information terminal is correspondingly increased to impair the portability of the terminal. Since the brightness of the backlight is lower than the brightness (illuminance) of external light, moreover, the visibility of the liquid crystal display device in outdoors is poor, thereby further impairing the portability of the mobile information terminal. In the above-mentioned mobile information terminal, the power consumption of the backlight
15
can be reduced by disposing the light-introducing portion
30
, but the exposed area of the light-introducing portion
30
is small, thereby causing a problem in that the amount of external light which can be introduced is limited. In accordance with the recent tendency of thinning a notebook-type personal computer, particularly, also the light-introducing portion
30
must be further thinned. Therefore, the size of the light-introducing portion
30
is further reduced.
SUMMARY OF THE INVENTION
The invention has been conducted in order to solve the problems. It is an object of the invention to reduce the power consumption of a backlight and improve the visibility in outdoors, thereby improving the portability of a mobile information terminal.
The invention has been conducted in order to attain the object, and provides a mobile information terminal having a cover comprising: a liquid crystal panel; and a light-introducing portion which introduces external light to illuminate the liquid crystal panel, the cover being connected to a main unit by at least one axis to be movable, wherein one end of the cover including the light-introducing portion has a shape which, when the cover is closed and swung to a position where the cover overlaps with the main unit, covers an area of an end portion of the main unit opposed to the axis, the area extending from an upper face to a side face.
Furthermore, a mobile information terminal is provided in which the light-introducing portion is disposed in an end portion opposed to the axis, a length of the cover between the light-introducing portion and the axis is longer than a length of the main unit between an end portion opposed to the light-introducing porti
Marushita Yasushi
Shimizu Makoto
Uehara Hisao
Fish & Richardson P.C.
Lee Guiyoung
O'Shea Sandra
Sanyo Electric Co,. Ltd.
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