Note: Descriptions are shown in the official language in which they were submitted.
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COMPUTER WITH ILLUMINATOR FOR KEYBOARD
Detailed Description of the Invention:
Field of the Invention
The present invention relates to battery-driven computers with a
light source for illuminating a keyboard thereof.
Background Art
Portable computers are excellent in portability because they are
small in size and light in weight, and can be used at any place
independently of commercial power sources by mounting a battery charger in
the interior. Generally, the portable computers are provided with a
liquid crystal display (LCD), a keyboard and a pointing device and many
contrivances have been made in order to economize the consumption power of
the battery. Since computers have generally been used in recent years at
places remote from offices, there is an increasingly strong demand for
using computers in an environment where the light is poor, for example, in
a train or a living room.
To use computers, there is a need for users to operate the keyboard
and the pointing device whilst viewing the LCD. Because most LCDs are
provided with a back light, users can view the screen even if the
surroundings are dark. However, since the keyboard and pointing device do
not emit light unless they employ fluorescent paint or material, users
cannot visually recognize a key position or a script on the key top in the
dark and therefore users, other than an experienced person who can handle
computers without relaying on vision, cannot sufficiently use computers
under such an environment. In addition, the back light of the LCD does
not provide enough illumination to operate the keyboard.
Published Unexamined Utility Model Application No. 59-4493 (creator
of device, Suganuma and Yajima) discloses a technique of providing an
illuminator in electronic equipment such as an electronic register and
illuminating a keyboard thereof, as shown in Figure 1. An illuminator is
provided in the upper portion of the front surface display section of the
register, and when the register is used, the keyboard can be illuminated.
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This electronic register, however, is not a portable type but an installed
type and is based on the assumption that commercial power sources can be
utilized. Thus the application does not disclose a way for disposing the
light source at the same position in a portable computer. In other words
there is no description of a specific method for disposing the light
source on the upper portion of the LCD of a portable computer. In
addition, the light source shown in Figure 1 is considered to be an
incandescent electric light.
Published Unexamined Patent Application No. 8-314598 (inventor,
Sugawara) discloses a technique of illuminating the keyboard of a personal
computer (PC), as shown in Figure 2. The light source is disposed between
the keyboard and the display section and attached on the main body of the
PC. Disposing the light source at this position, however, will cause some
problems. First, in portable computers, a large area is used on this side
of the keyboard in order to ensure the palm rest portion that holds the
palms of a user when the user operates the keyboard. For this reason, in
many cases it is difficult to ensure space for the light source at the
position shown in Figure 2. In addition, there is a need to make the
light source higher than the plane of the key top of the keyboard and
provide a cover, in order to illuminate the entire keyboard from the
position of the light source shown in Figure 2. For this reason, if an
attempt is made to close the cover including the LCD, the computer will
become considerably thick. Furthermore, because the entire keyboard is
illuminated with the light source disposed at the position shown in Figure
2, there is a need to provide a plurality of point light sources or an
elongated light source and therefore a problem with the consumption power
of the battery will arise.
In addition, the light source is partially covered so that light is
not emitted to a place other than the keyboard. Furthermore, in the
aforementioned specification No. 8-314598 it has been described that "In
addition, when the light source is attached to the liquid crystal section,
it becomes possible to visually recognize the keyboard in the dark place,
but there is a problem that (1) a large-capacity light source is required,
because the liquid crystal section and the keyboard are illuminated and
(2) in the case of a liquid crystal section with a back light, light
enters the liquid crystal and therefore disturbs the field of vision."
Therefore, the aforementioned specification No. 8-314598 has taught that
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attaching the light source to the liquid crystal section has been given up
because there is a problem from the viewpoint of both the capacity of the
light source and the visual field with respect to the liquid crystal
section.
Published Unexamined Utility Model Application No. 7-25415 (creator
of device, Shinomura and Sasaki) discloses a technique of providing a
detachable light source in a notebook-sized PC and illuminating the
keyboard. In this publication, the light source is not attached to the
main body of the PC and is provided as a separate unit (ie is detachable).
Since this method requires that the light source be carried separately
from the computer it does not complement the portability of the PC. Also
the operation of detachably attaching the light source will give users
trouble.
Summary of the Inveation
In accordance with a first aspect of the present invention, there is
provided a computer capable of battery powered operation, having a
keyboard and a display comprising: an LED holder installed at
approximately an upper edge of the display, the holder having a wall
formed with an aperture; and an LED installed inside the wall of the LED
holder, wherein light radiated from the LED illuminates the keyboard by
passing through the aperture.
Preferably a light emitting diode (LED) is selected as a light
source for keyboard illumination. Generally, the LED has been used in
displaying the operating state of electronic equipment and has been used
as a device for displaying states rather than as a device for
illumination. However, since LEDs with a relatively high luminous
intensity suitable for illumination have been developed in recent years,
the LED is used in a preferred embodiment to illuminate the keyboard of a
portable computer to solve problems not solved in the background art. The
LED is suitable as an illuminator for a keyboard to be mounted on a
battery drivable computer, because it is small, and does not degrade the
portability of the computer to which it is attached. It is also low in
power consumption and so barely shortens the operating time of a battery.
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In addition, according to the preferred embodiment an LED holder is
attached to substantially the upper edge of a display and an LED is held
within the LED holder. This position is most suitable as a place for
attaching a light source because there is no obstacle with respect to
keyboard illumination. In addition, by disposing a light source here,
only a single point light source illuminates the entire keyboard and there
is no need to prepare a plurality of point light sources, a line light
source, or a surface light source. The wall of the LED holder is formed
with an aperture, and light from this LED is passed through the aperture
and guided to the keyboard. The distribution of the light passed through
the aperture is preferably controlled by adjusting the position at which
the LED holder is attached and also the size and position of the aperture
in the wall of the LED holder.
In accordance with the preferred embodiment, a part of the light
radiated from the LED is masked by the wall of the LED holder, and the
remaining light passing through the aperture does not directly illuminate
the display. This is realizable by suitably selecting, for example, the
configuration of the holder, the attached position of the holder, the
position of the aperture, the size of the aperture, and the like. This
overcomes the problem of the prior art that when a light source is
provided in the upper portion of the display, light radiated from the
light source will disturb the visual recognition of the display.
In the preferred embodiment, when the display is opened so that it
is held at approximately 90 degrees to the main body, light from the LED
passes through the aperture so that it illuminates substantially the
keyboard alone. The angle of approximately 90 degrees is considered to be
the smallest angle at which a user uses the computer. If the entire
keyboard is illuminated at this angle, the illumination of the keyboard
will be sufficiently ensured even if the back cover is opened further.
This is also realizable by suitably selecting, for example, a parameter
related to the aperture.
Preferably, the LED holder is provided with a shutter that adjusts
the opening degree of the aperture. Therefore, the user can adjust light
distribution in accordance with the inclined state of the display by
manually adjusting the position of the shutter.
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According to the preferred embodiment, an LCD is selected as a
display and a portable computer is selected as a computer. The present
invention is particularly applicable to portable computers, because there
are many cases where keyboard illumination is required, as compared with
5 an installed type.
Preferably, the LED is switched off when the back cover is closed.
In this way, the battery is prevented from being consumed by closing the
back cover without switching off the LED.
l0
Thus, a battery drivable computer is preferably provided which
disposes a light emitting diode (LED) on the upper portion of a display
such as a liquid crystal display (LCD) and realizes an excellent
illumination of keyboard. A computer is provided that can be utilized by
a battery driven operation with low consumption power (even when the
illuminator is lit) and without occupying a lot of space and which is able
to perform effective keyboard illumination without having an adverse
effect on the visual recognition of the display. Furthermore portability
is not degraded.
The technique of illuminating the keyboard of a portable computer
with a light source disposed on the upper portion of the LCD has hitherto
been difficult and has not been realized. But, when the LCD is open in
order to use the portable computer, there is no obstacle to intercept
light between the upper portion of the LCD and the keyboard and therefore
it follows that the upper portion of the LCD is most efficient as a
position of illuminating the keyboard. However, since a distance from the
light source to the keyboard becomes longer, it becomes important that an
illuminator as a light source have a great luminous intensity and a lower
energy consumption amount. Furthermore, when the keyboard is illuminated
from the upper portion of the LCD, there is a need to elaborate a plan so
that the visual recognition of the LCD is not disturbed by direct light
incident on the LCD. The present invention preferably solves these
problems and realizes illumination for the keyboard of a portable computer
not obtained in the background art.
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Brief Description of the Drawings
A preferred embodiment of the present invention will now be
described in detail, by way of example only, and with reference to the
following drawings:
Figure 1 is a schematic diagram showing a conventional register with
an illuminator for the keyboard;
Figure 2 is a schematic diagram showing a conventional personal
computer with a light source for the keyboard;
Figure 3 is a perspective view showing a preferred embodiment of a
portable computer according to the present invention;
Figure 4 is an exploded view showing the disassembled state of the
back cover, the LCD, and the LED holder shown in Figure 3 in accordance
with a preferred embodiment of the present invention;
Figure 5 is a detailed diagram showing a preferred embodiment of the
LED holder shown in Figure 4;
Figure 6 is a sectional view showing how the LED holder is attached
in accordance with a preferred embodiment of the present invention;
Figure 7 is a diagram for describing the light distribution
characteristic of the light emitted from an LED held by the LED holder in
accordance with a preferred embodiment of the present invention;
Figure 8 is a diagram for describing the light distribution
characteristic in accordance with a preferred embodiment of the present
invention;
Figure 9 is a sectional view of an LED holder with a shutter in
accordance with a preferred embodiment of the present invention; and
Figure 10 is a circuit diagram showing a preferred embodiment of a
lighting control circuit that switches on and off the LED holder.
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Detailed Description
Figure 3 shows a preferred embodiment of a notebook-sized portable computer
100 to
which the present invention is applied. A keyboard 103 is disposed on the
upper surface of a
main body 101, and a palm rest 111, for holding the palms of a user when the
user operates the
keyboard, is disposed on this side of the keyboard. A back cover 105 is
attached at one end
thereof to approximately an end of the main body 101 so that it can be opened
and closed. The
back cover 105 plays a role of covering the keyboard 103 and the palm rest 111
in its entirety
when the computer is not being used. A liquid crystal display (LCD) 109 is
attached to the back
1 o cover 1 OS and a bezel 107 is also attached to the back cover 1 OS so that
it covers the
circumference of the LCD 109 and the circumference of the back cover. In using
the computer
100, the user rotates the back cover 105 to 90 degrees or greater with respect
to the main body
101 and operates the keyboard 103 whilst viewing the LCD.
The computer 100 is further provided with an LED holder 150, which holds an
LED for
15 keyboard illumination, and an LED switch 113 in the interior thereof. With
the back cover 105
opened, the user operates the switch 113 to light the LED, whereby the
keyboard 103 can be
illuminated.
Figure 4 illustrates the disassembled state of the back cover 105, the LCD
109, the bezel
107, and the LED holder 150 according to the preferred embodiment. The back
cover 105 is
2 o provided with a boss 120 threaded inside, and the LED holder 150 is passed
through the aperture
117 of the bezel 10? and is attached to the boss 113 by means of a screw 115.
The back cover
105 is formed with bosses 120 that attach the LCD 109 to the back cover 105.
The bezel 107 is
provided with the switch 113.
Figure 5 shows an enlarged view of the LED holder 150 according to the
preferred
2 s embodiment. In Figure SA the fixing portion 151 of the LED holder 150 is
attached to the boss
113. Figure SB shows a sectional view taken along line A-A in Figure SA;
Figure SC shows a
bottom view of the boss 113 shown in Figure SB. Figure SB shows an LED fixing
portion 159
which preferably extends inward from a side wall 157, the central portion of
the LED fixing
portion 159 being provided with an aperture so that it can insert and fix the
LED 155. The LED
30 155 is inserted into this
JP9-1999-0129 7
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aperture from the upper portion and fixed to the LED holder 150. In
addition, as shown in Figure 5C, the bottom portion 153 of the LED holder
150 is provided with an aperture 161. Part of the light emitted from the
LED 155 is intercepted by the bottom portion 153, while the remaining part
is emitted outside the LED holder 150 via the aperture 161.
The preferable embodiment has adopted the LED as the light source.
An LED 155, NSPWF50BS manufactured by Nichia Chemical Industries, Ltd.,
can for example, be utilized. This LED 155 has luminous intensity 0.18 cd
and power consumption 252 mW and thus has characteristics of luminous
intensity and lower consumption power sufficient to illuminate the
keyboard. In addition, the sectional size of the light emitting portion
is as small as 2 x 4 mm and can be housed in the LED holder the size shown
in Figure 5. Because in the preferred embodiment the battery capacity of
the computer 100 is 4800 mAh, the rate of the power consumption of the LED
to the battery capacity is about 1.6~. The computer 100 is therefore is
able to operate for 3 hr under standard operating conditions with the LED
155 off, and even if the LED 155 is kept on under the same condition, the
operating time of the computer 100 will be shortened only by about 3 min.
Figure 6 shows the attached state of the LED holder 150 to the back
cover 105 according to the preferred embodiment. The LED holder 150 and
the LCD 109 are attached to the back cover 105 by the boss 113 and the
bosses 120, respectively. The bezel 107 covers the circumference of the
LCD 109 and the end portion of the back cover 105, and at the portion to
which the LED holder 150 is attached, the bezel 107 is provided with an
aperture so that the bottom portion 153 of the LED holder appears outside
the bezel.
In Figure 6(B), according to the preferred embodiment, the size of
the aperture 161, the distance of the aperture 161 from the surface of the
LCD 109, and the angle of the bottom portion 153 with respect to the
surface of the LCD are important. This is because is that these
parameters become major causes which determine the light distribution
characteristic of the light radiated downward from the LED holder 150. In
the preferred embodiment, the size of the aperture 161 is 4 mm x 2 mm, the
distance from the LCD surface to the aperture 161 is 5 mm, and the angle
of the bottom portion 153 with respect to the LCD surface is approximately
90 degrees. This light distribution prevents light radiated by the LED
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155 from directly illuminating the LCD surface, whereby the visual
recognition of the LCD is not disturbed. Furthermore, the light
distribution characteristic is determined so that, during use of the
computer, the entire keyboard is effectively illuminated in the range of a
predetermined inclined angle of the back cover 105. The setting of the
light distribution characteristic will be described in detail below.
Figure 7 shows, in the portable computer 100, the light distribution
characteristic of the light emitted from the LED holder 150 housing the
LED 155 according to the preferred embodiment. Figure 7A is a side view,
the back cover 105 being opened so that it is held at approximately 90
degrees to the main body 101. In the inclined state of the LCD, a ray of
light 131 nearest to the LCD 106 illuminates the end of the keyboard
nearest to the LCD. The light ray 131 is determined by the angle of the
bottom portion 153 of the LED holder 159 with respect to the LCD surface,
the size of the aperture 161, and the distance of the aperture 161 from
the LCD surface, as shown in Figure 6B. In Figure 7A, the light ray 131
has been illustrated so that it illuminates the portion of the keyboard
103 nearest to the LCD 109, but the illustration has been made of a light
ray having illuminance suitable for keyboard illumination. Actually, a
weak ray of light going from the aperture 161 toward the LCD 109 is also
emitted.
The distribution of this weak light ray according to a preferred
embodiment will be described with reference to Figure 8. Part of the
light emitted from the LED holder 150 includes a weak light ray going in
the direction of the LCD 109, like the light ray 133. However, in this
embodiment, the above-mentioned parameters, such as the size of the
aperture 161 and the like, are determined so that the light ray 133 does
not go to the LCD side beyond the coupled portion 137 between the back
cover 105 and the main body 101. Therefore, even when the back cover is
used at any angle, there is no possibility that the light will illuminate
the LCD 109 directly and therefore there is no possibility that the visual
recognition of the LCD will be disturbed.
Returning again to Figure 7, the above-mentioned parameters, such as
the size of the aperture 161 and the like, are determined so that, when
the back cover 105 is open to 90 degrees, a ray of light 133 farthest from
the LCD 109 illuminates the farthest end of the keyboard 103 from the LCD.
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Figure 7B shows a plan view of the computer shown in Figure 7A in
accordance with the preferred embodiment. As shown in Figure 7B, the
light distribution characteristic is determined so that, when the back
cover is open to 90 degrees, the entire keyboard is illuminated.
5 Generally, the computer 100 is used in a range of 110 to 135 degrees.
Therefore, the computer 100 is often used with the back cover opened
further than the position of Figure 7A with respect to the main body 101.
If the inclined angle of the back cover 105 is gradually increased, the
light ray 133 will move to this side of the main body 101 and move beyond
10 the main body 101. However, the entire keyboard 103 is still illuminated,
so there is no obstacle in the operation of the keyboard under a dark
environment. Since the movement quantity of the distal end of the light
ray 131 is extremely small, there is also no obstacle in the illumination
of the end of the keyboard 103 near the LCD.
Figure 9 illustrates a shutter 163 provided within the LED holder in
order to prevent the light ray 133 from extending beyond the main body 101
and illuminating an unnecessary range when the back cover 105 is gradually
inclined in accordance with a preferred embodiment of the present
invention. The shutter 163 is provided within the LED holder 150 so that
it is manually slidable. A mechanism for manually sliding the shutter 163
may be a mechanism which extends a shaft for fixing the shutter 163
outward from the side wall 157 (see fig 5B) of the LED holder 150 and
attaches a control dial to the shaft, or may adopt any other known
mechanism. It is preferable that the slid shutter 163 be provided with a
locking mechanism that locks the shutter 163 at arbitrary positions. The
shutter 163 fulfills a role of adjusting the opening degree of the
aperture 161 in accordance with the inclined angle of the back cover 105.
The control of switching on and off the LED in accordance with the
preferred embodiment is performed by the switch 113 shown in Figure 3. If
the LED 155 is always on, when the switch 113 is on, there are cases where
the back cover 105 is closed with the LED 155 on. To prevent this, a
second switch 114 interlocking with the operation of opening and closing
the back cover 105 is preferably added to a lighting control circuit, as
shown in Figure 10. The LED 155, the switch 113, and the second switch
are connected in series to a power source. The second switch 114 is on
only when the back cover is open. In this state, the switch 113 is
switched on or off, whereby the LED 155 can be switched on or off.
