Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2000-01-19
2003-11-04
Shalwala, Bipin (Department: 2673)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S085000, C345S086000, C359S290000, C359S291000, C359S292000, C359S293000, C359S294000, C359S295000
Reexamination Certificate
active
06642913
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a light modulation element for modulating light from a light guide plate by means of a flexible thin film displaced by the electromechanical operation, an exposure unit for exposing a sensitive material to light with the light modulation element, and a flat-panel display unit for displaying an image with the light modulation element.
2. Description of the Related Art
For example, a liquid crystal display, a plasma display, and the like are named as representative thin flat-panel display units. However, in the liquid crystal display, light from backlight is allowed to pass through a large number of layers of a polarizing plate, a transparent electrode, and a color filter and a problem of lowering the light use efficiency arises; in the plasma display, diaphragm formation for discharge is executed for each pixel, thus it is difficult to provide high intensity at high efficiency as definition becomes high, and drive voltage is also high, leading to an increase in costs.
To solve such problems, in recent years, a flat-panel display unit for displacing a flexible thin film by the electromechanical operation, thereby modulating light from a light source for displaying an image has been developed. For example, such a flat-panel display unit is described in the following document:
Waveguide Panel Display Using Electromechanical Spatial Modulators, 1988, SID International Symposium Digest of Technical Papers, p.1022-p.1025.
The flat-panel display unit comprises a plurality of parallel optical waveguides
92
placed side by side on a front glass
91
and an LED (light emitting diode) array
95
connected to one end side of the optical waveguides
92
via a light guide member
94
having a microlens
93
, as shown in FIG.
16
. The LED array
95
comprises a plurality of light emission parts listed in one dimension and the light emission parts are provided in a one-to-one correspondence with the optical waveguides
92
. A plurality of parallel flexible thin films (light switches)
96
are placed side by side above the optical waveguides
92
with a gap in a direction orthogonal to the optical waveguides
92
. A rear glass
97
with only a part brought into contact with the flexible thin film
96
is placed above the flexible thin films
96
and supports the flexible thin films
96
displaceably.
In the described flat-panel display unit
90
, when a voltage is applied to an electrode on a predetermined flexible thin film
96
, the flexible thin film
96
is displaced by an electrostatic force in a direction in which it approaches the optical waveguide
92
side, as shown in FIG.
17
. On the other hand, the LED array
95
emits light based on an image signal in synchronization therewith. Then, light advancing while being totally reflected in the optical waveguide
92
is guided into the flexible thin film
96
, is reflected on a mirror
98
placed in the flexible thin film
96
, and again is made incident on the optical waveguide
92
in a direction roughly perpendicular to the optical waveguide
92
. The light made incident on the optical waveguide
92
in the direction roughly perpendicular to the optical waveguide
92
cannot hold the angle of total reflection, passes through the optical waveguide
92
, and is emitted from the front glass
91
side.
According to the flat-panel display unit, the flexible thin film
96
is displaced by an electrostatic force, thus the operation of the flexible thin film
96
can be followed at high speed; in addition, unlike the liquid crystal display, light is not allowed to pass through a large number of layers and unlike the plasma display, diaphragm formation in a discharge section and a high-voltage drive circuit become unnecessary, so that it is made possible to provide a fast and inexpensive flat-panel display unit.
However, in the described flat-panel display unit
90
of the optical waveguide type, light is emitted by means of the reflection film in the flexible thin film, thus the emitted light involves a directivity and viewability worsens.
For color display, an LED array of a number of colors needs to be used as a light source and the light source and the optical system are limited; in addition, the unit configuration becomes intricate and the manufacturing process becomes complicated, resulting in an increase in costs.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a light modulation element less depending on a viewing angle, enabling highly efficient luminescent display, and providing high light use efficiency although the structure is simple, an exposure unit using the light modulation element, and a flat-panel display unit using the light modulation element.
According to this invention, there is provided a light modulation element comprising a light guide body for guiding light from a light source and a flexible thin film having a fluorescent material being provided facing the light guide body, characterized in that the distance between the flexible thin film and the light guide body is changed by the electromechanical operation and light emission of the fluorescent material excited by the guided light is controlled.
In the light modulation element, the flexible thin film having the fluorescent material is displaced by the electromechanical operation, whereby light guided from the light source into the light guide body is guided into the flexible thin film side for exciting the fluorescent material to emit light or light is not guided, whereby light modulation is executed. Since the flexible thin film thus comprises the fluorescent material, the structure and the manufacturing process of the element are simplified and the manufacturing costs can be reduced drastically. Since the fluorescent material is used, a scattered light emission state is entered at the light emission time and dependency of a viewing angle is scarcely produced, improving viewability. Further, light is applied directly to the fluorescent material, thus the fluorescent material can be excited for emitting light in high efficiency.
Various electromechanical effects of an electrostatic effect, an electromagnetic effect, a piezoelectric effect, etc., can be used as means of the electromechanical operation.
In this invention, the electromechanical operation is performed by generating an electrostatic force between the flexible thin film and the light guide body.
In the light modulation element, a voltage is applied to the flexible thin film and the light guide body, whereby an electrostatic force is generated between the flexible thin film and the light guide body, the flexible thin film performs the electromechanical operation smoothly at high speed and reliably by the generated electrostatic force, and stable light modulation is executed. The element using an electrostatic force can be provided by executing a simple manufacturing process for forming an electrode on the flexible thin film, and the costs can be reduced. Further, because of voltage drive type, it is made possible to execute low-voltage drive by optimizing the material and shape of the thin film.
In this invention, the light guide body is formed with a first electrode, the flexible thin film is formed with a second electrode, and a voltage is applied to the first electrode and the second electrode, thereby generating an electrostatic force.
In the light modulation element, a voltage is applied to the first electrode on the light guide body side and the second electrode on the flexible thin film side, whereby an electrostatic force is generated between the electrodes and the second electrode on the flexible thin film side is displaced, whereby light modulation is executed. Thus, a necessary structure can be formed on a single substrate and it is made possible to manufacture the element with high accuracy at low costs.
In this invention, the fluorescent material is a fluorescent layer formed on a surface of the flexible thin film.
In the light modulation element, the fluorescent film can be formed o
Kimura Koichi
Sawano Mitsuru
Dharia Prabodh M.
Fuji Photo Film Co. , Ltd.
Shalwala Bipin
Sughrue & Mion, PLLC
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