Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2001-12-05
2004-02-10
Wu, Xiao (Department: 2674)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S088000
Reexamination Certificate
active
06690348
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a transmissive color liquid crystal display utilizing the color field sequential method.
2. Prior Art
FIG. 18
is a cross sectional view of a backlight used in a conventional transmissive liquid crystal display disclosed in JP-A-8-122534. In
FIG. 18
, numeral
101
designates a backlight
101
including a light-guiding plate
102
, a reflection layer
103
disposed on the rear surface of the light-guiding plate
102
, a diffusion layer
104
disposed on the front surface of the light-guiding plate
102
, a linear light source
105
disposed in the vicinity of a side edge of the light-guiding plate
102
, and a reflector
106
surrounding the linear light source
105
. Numeral
107
designates an open side edge of the light-guiding plate
102
opposite to the linear light source
105
. The open side edge
107
is exposed and closed by a shutter plate
108
arranged pivotally about an axis
108
a.
On a surface of the shutter plate
108
, which may face to the open side edge
107
, a reflection film
109
is disposed.
Next, an operation of the backlight
101
will be described. The shutter plate
108
is opened so as to expose the open side edge
107
in the use of the liquid crystal display in the situation where environmental illumination is sufficient, for example, the outdoors. The rays from the linear light source
105
, which will be referred to as internal rays hereinafter, enter light-guiding plate
102
directly from the linear light source
105
or indirectly after reflection on the reflector
106
. While some fractions of internal rays leak out from open side edge
107
, external rays including the rays of the sun enter the light-guiding plate
102
through the open side edge
107
, and the incoming external rays are in excess of internal rays outgoing through the open side edge
107
. Some fractions of internal and external rays in the light-guiding plate
102
reflect at the reflection layer
103
so as to be oriented frontward. Internal and external rays in the light-guiding plate
102
finally outgoes from the backlight
101
uniformly along the direction indicated by arrow A while the rays are diffused by the diffusion layer
104
.
The shutter plate
108
is closed so as to cover the open side edge
107
in the use of the liquid crystal display when environmental illumination is insufficient, for example, in a house since external rays entering through the open side edge
107
are less than internal rays outgoing through the open side edge
107
if shutter plate
108
is open. Only internal rays from the reflector
106
enter light-guiding plate
102
directly from the linear light source
105
or indirectly after reflection on the reflector
106
. Some fractions of internal rays reflect on the reflection film
109
and return into the light-guiding plate
102
. Some fractions of internal rays in the light-guiding plate
102
reflect at the reflection layer
103
so as to be oriented frontward. Internal rays in the light-guiding plate
102
finally outgoes from the backlight
101
uniformly along the direction indicated by arrow A while the rays are diffused by the diffusion layer
104
.
JP-A-8-122534 also discloses a modified backlight comprises a special reflection mirror at the open side edge
107
. The reflection mirror has a transmittance property that varies depending upon angles of incidence of rays, whereby the mirror reflects rays inside the light-guiding plate
102
, but admits external rays to the light-guiding plate
102
.
JP-A-8-122534 discloses another modified backlight comprises a detector for detecting the illumination of external rays, and drive means, e.g., a motor, for opening and closing the open side edge
107
automatically in response to the environmental illumination.
FIG. 19
is a cross sectional view of another conventional transmissive liquid crystal display disclosed in JP-A-10-68948. In
FIG. 19
, numeral
201
designates a transmissive liquid crystal display including a liquid crystal display panel assembly
202
, a fenestra
203
formed in the housing (not shown) of the liquid crystal display and disposed in the vicinity of the liquid crystal display panel assembly
202
, a first light-guiding path
204
arranged behind the liquid crystal display panel assembly
202
, a lamp unit
205
disposed in the vicinity of the side end of the first light-guiding path
204
, and a second light-guiding path
206
for guiding external rays passing through the fenestra
203
to the first light-guiding path
204
. Numeral
207
identifies a shutter plate for opening and closing the fenestra
203
. A diffusion layer
208
is disposed on the rear surface of the first light-guiding path
204
. Low-reflectance films
209
cover the front surface of the liquid crystal display panel assembly
202
and the fenestra
203
, respectively. Reflection films
210
are disposed on the internal walls of the second light-guiding path
206
and on the internal wall of the shutter plate
207
, respectively.
Next, an operation of the transmissive liquid crystal display
201
will be described. The lamp unit
205
is turned off and the shutter plate
207
is opened so as to expose the fenestra
203
in the use of the liquid crystal display when the environment is sufficiently bright. In this case, external rays including the rays of the sun enter the second light-guiding path
206
through the fenestra
203
. While some fractions of external rays reflect on the reflection film
210
on the inner walls of the second light-guiding path
206
, external rays reach the first light-guiding path
204
. Then, the back surface of the liquid crystal display panel assembly
202
is irradiated with external rays uniformly while the diffusion layer
208
diffuses external rays.
On the contrary, the lamp unit
205
is turned on when the environmental illumination is insufficient. Accordingly, the rays from the lamp unit
205
, which will be referred to as internal rays hereinafter, enters first light-guiding path
204
. In addition, the shutter plate
207
is shut to close the fenestra
203
since the illumination required for irradiating the liquid crystal cannot be ensured if internal rays quit through the second light-guiding path
206
and the fenestra
203
. Another reason for closing the shutter plate
207
is for protecting unanticipated external rays from the fenestra
203
that may directly come into human eyeshot, causing difficulty to watch the display panel. By the closed arrangement, internal rays that have entered the second light-guiding path
206
reflect on the reflection film
210
on the shutter plate
207
to return to the second light-guiding path
206
, reflect on the reflection film
210
on the inner wall of the second light-guiding path
206
, and enter the first light-guiding path
204
, again. Internal rays that have entered the first light-guiding path
204
are diffused by the diffusion layer
208
and shine up the reverse side of the liquid crystal display panel assembly
202
uniformly.
JP-A-10-68948 also discloses a modified structure comprising a light-collecting element for collecting external rays, an optical fiber for guiding external rays collected by the light-collecting element to the fenestra
203
, and a coupling element for coupling the optical fiber with the fenestra
203
.
The conventional transmissive liquid crystal display shown in
FIG. 18
has a drawback that primary color components, e.g., R (red), G (green), and B (blue) cannot be extracted from external rays admitted through the open side edge
107
. Therefore, when external rays are employed, full color images are not presented on the liquid crystal display panel assembly without provision of color filters.
In addition, the conventional transmissive liquid crystal display shown in
FIG. 18
has another drawback that it is not easy to control the entrance of external rays and the leak of the internal ray since the control of the entrance of external rays and the leak of the internal ray is ac
Furuki Ichiro
Sato Tsuneo
Takahashi Masatoshi
Yamada Keiki
Birch & Stewart Kolasch & Birch, LLP
Mitsubishi Denki & Kabushiki Kaisha
Wu Xiao
LandOfFree
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