Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2001-12-07
2004-11-09
Vu, David (Department: 2821)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S205000
Reexamination Certificate
active
06816140
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a displaying device and a displaying method, and a manufacturing method of the device, which is a flat type displaying device used for such as personal digital assistants (PDA), a mobile communication terminal, a personal computer (PC), a television (TV) set, in particular, in which waveguides being a thin type, having light weight, and whose manufacturing cost is low, are used.
DESCRIPTION OF THE RELATED ART
A liquid crystal display (LCD) has been used as a displaying device for a PDA, a mobile communication terminal, a PC, a TV set, a video game set, and so on. Especially, a thin film transistor (TFT)-LCD, which drives each liquid crystal cell by using a TFT provided at each pixel, has been widely used, because an image can be displayed in high resolution and high speed response.
However, since the manufacturing processes of the TFT are complicated, the larger its displaying screen is, the higher its manufacturing cost is. Furthermore, the size of the screen of the LCD is limited to a certain size depending on performance of the TFT manufacturing equipment such as spattering equipment, chemical vapor deposition (CVD) equipment, and lithography equipment.
In order to solve these problems, Japanese Patent Application Laid-Open No. 2000-29398 discloses “Flat Panel Display using Waveguides”. In this patent application, light from a light source is attenuated corresponding to a video signal. And the attenuated light is inputted to plural waveguides arrayed regularly. And an image is displayed by extracting light from designated places of the waveguides corresponding to the video signal repeatedly.
Referring now to drawings, this conventional flat panel display using waveguides is explained.
FIG. 1
is a block diagram showing the conventional flat panel display disclosed in the Japanese Patent Application Laid-Open No. 2000-29398. As shown in
FIG. 1
, a video signal is inputted to a driving unit
130
, and a control signal C
1
is outputted to a gray level controlling unit
134
and a control signal C
2
is outputted to a display panel
132
from the driving unit
130
. Light from a light source
136
is attenuated according to the control signal C
1
and the attenuated light is inputted to the display panel
132
. The display panel
132
consists of waveguides and a light extracting means for extracting light from these waveguides.
FIG. 2
is a sectional view showing the display panel
132
shown in FIG.
1
. Optical fibers without clad
123
, whose cross-section is rectangle, are regularly arrayed on a substrate for optical fibers
124
. As described above, these optical fibers without clad
123
do not have clad which is different from conventional optical fibers. And a liquid crystal layer
122
is formed on the upper surface of these optical fibers without clad
123
. The liquid crystal layer
122
changes its refractive index when a voltage is applied.
Optical fibers without clad
121
, whose cross-section is cylindrical, are arrayed regularly in the upper part of the liquid crystal layer
122
. And a transparent protection panel
120
is formed on the upper surfaces of the optical fibers without clad
121
. An optical adhesive
127
is disposed between the transparent protection panel
120
and the optical fibers without clad
121
. Further, first electrodes
125
are disposed on the lower surface of the transparent protection panel
120
, and second electrodes
126
are disposed on the lower surface of the substrate for optical fibers
124
. Voltages are applied to the first electrodes
125
and the second electrodes
126
respectively. Alternatively, the second electrodes
126
can be disposed on the lower surface of the liquid crystal layer
122
or on the lower surface of the optical fiber without clad
123
.
Next, referring to
FIGS. 1 and 2
, an operation of the conventional flat panel display using waveguides is explained. The light from the light source
136
is controlled (attenuated) by the gray level controlling unit
134
according to a control signal C
1
. And this attenuated light is inputted to an optical fiber
123
. A control signal C
2
determines a position where the light is entered. When there is no potential difference between the first electrode
125
and the second electrode
126
, this light is propagated in the optical fiber without clad
123
by repeating the total reflection inside.
When a potential difference is applied between the designated first and second electrodes
125
and
126
selected by the control signal C
2
, the refractive index of the liquid crystal layer
122
becomes high. And as shown in
FIG. 2
, the light, which does not satisfy the condition for the total reflection, is extracted from the designated optical fiber without clad
123
. And the direction of the extracted light is changed by the refraction at the boundary of the optical fiber without clad
121
, and the light reaches an observer (not shown). The operation mentioned above is repeated for all of the points on the surface of the display panel
132
, and an image is displayed on the display panel
132
.
FIG. 3
is a sectional view showing the gray level controlling unit
134
shown in FIG.
1
. As shown in
FIG. 3
, in the gray level controlling unit
134
, optical fibers without clad
144
whose cross-section is rectangular are arrayed on a substrate for optical fibers
146
, and a protection panel
142
having third electrodes
140
and fourth electrodes
141
is disposed in the upper surface of the optical fibers without clad
144
. And a liquid crystal layer
148
, a light absorbing layer
150
, and a fifth electrode
152
are layered in a part of the substrate for optical fibers
146
at the position where the substrate for optical fibers
146
contacts with the optical fibers without clad
144
.
Next, referring to
FIGS. 1 and 3
, an operation of the gray level controlling unit
134
is explained. When voltages are not applied to the third electrode
140
, the fourth electrode
141
, and the fifth electrode
152
, light inputted to the optical fiber without clad
144
from the light source
136
repeats the total reflection in the optical fiber without clad
144
and inputted to the display panel
132
with almost no attenuation. And, for example, when a potential difference is applied between the fourth electrode
141
and the fifth electrode
152
, the refractive index of the liquid crystal layer
148
becomes high, and the condition of the total reflection is broken at the boundary of the optical fiber without clad
144
.
Light not satisfying the condition for the total reflection is inputted to the liquid crystal layer
148
and is absorbed by the light absorbing layer
150
. As mentioned above, the amount of light supplied to the display panel
132
can be controlled by the gray level controlling unit
134
based on whether voltages are applied or not to the gray level controlling unit
134
.
As mentioned above, the conventional flat panel display using waveguides consists of the light source
136
, the gray level controlling unit
134
, the display panel
132
, and the driving unit
130
. And the display panel
132
includes the waveguides and the light extracting means, and the driving unit
130
gives control signals to the gray level controlling unit
134
and the display panel
132
. In this, an important role to extract light propagating in the waveguides in the display panel
132
is executed by a specific material. The refractive index of this specific material must be changed by application of a voltage. In the conventional flat panel display using waveguides, as mentioned above, the liquid crystal is used as this material.
And there is also another conventional displaying device having waveguides and a light extracting means. Japanese Patent Application Laid-Open No. SHO 59-148030 discloses “Optical Fiber Displaying Device”. In this patent application, nitroglycerin films are formed at a part of an optical fiber with clad, and two transparent electrodes are disposed at the nitroglyce
NEC Corporation
Scully Scott Murphy & Presser
Vu David
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