Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
2001-12-21
2004-06-22
Liang, Regina (Department: 2674)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C359S290000, C385S901000
Reexamination Certificate
active
06753846
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a reflective display device for displaying a screen image corresponding to an input image signal on a display panel by selectively driving an actuator element depending upon an attribute of the image signal.
2. Description of the Related Art
Cathode ray tubes (CRT), liquid crystal display devices or the like have been known as the display device.
Usual television receivers, monitors for computers or the like have also been known as the cathode ray tube. Although the cathode ray tube has a bright screen, it consumes a large amount of electric power. In the cathode ray tube, further, the depth of the display device is large as compared with the size of the screen.
In comparison with the cathode ray tube, the liquid crystal display device is small, and consumes a small amount of electric power. However, brightness of the liquid crystal display device is not good. Further, viewing angle of the crystal display device is not wide.
To display a color image on the screen in the cathode ray tube and the liquid crystal display device, it is necessary to use many picture elements (image pixels), which is three times as many as the picture elements of a black-and-white screen. Therefore, the device itself is complicated, a large amount of electric power is consumed, and thus, the cost is relatively high.
As a solution of the above problems, the applicant has proposed a novel display device (see, for example, Japanese Laid-Open Patent Publication No. 7-287176). As shown in
FIG. 16
, this display device includes actuator elements
400
arranged for respective picture elements. Each of the actuator elements
400
comprises a main actuator element
408
including a piezoelectric/electrostrictive layer
402
and an upper electrode
404
and a lower electrode
406
formed on upper and lower surfaces of the piezoelectric/electrostrictive layer
402
respectively, and an actuator substrate
414
including a vibrating section
410
and a fixed section
412
disposed under the main actuator element
408
. The lower electrode
406
of the main actuator element
408
contacts the vibrating section
410
. The main actuator element
408
is supported by the vibrating section
410
.
The actuator substrate
414
is composed of ceramics in which the vibrating section
410
and the fixed section
412
are integrated into one unit. A recess
416
is formed in the actuator substrate
414
so that the vibrating section
410
is thin-walled.
A displacement-transmitting section
420
for obtaining a predetermined contact area with an optical waveguide plate
418
is connected to the upper electrode
404
of the main actuator element
408
. In the illustrative display device shown in
FIG. 16
, the displacement-transmitting section
420
is located near the optical waveguide plate
418
in the OFF selection state or the unselection state in which the actuator element
400
stands still, while it contacts the optical waveguide plate
418
in the ON selection state at a distance of not more than the wavelength of the light.
The light
422
is introduced, for example, from a lateral end of the optical waveguide plate
418
. In this arrangement, all of the light
422
is totally reflected in the optical waveguide plate
418
without being transmitted through front and back surfaces thereof by controlling the magnitude of the refractive index of the optical waveguide plate
418
. In this state, a voltage signal corresponding to an attribute of an image signal is selectively applied to the actuator element
400
by the upper electrode
404
and the lower electrode
406
so that the actuator element
400
may make a variety of displacement actions in conformity with the ON selection, the OFF selection, and the unselection. Thus, the displacement-transmitting section
420
is controlled for its contact with and separation from the optical waveguide plate
418
. Accordingly, the scattered light (leakage light)
424
is controlled at a predetermined portion of the optical waveguide plate
418
, and a screen image corresponding to the image signal is displayed on the optical waveguide plate
418
.
When a color image is displayed using the display device, light sources for the three primary colors are switched to control the light emission time for the three primary colors, while synchronizing the contact time between the optical waveguide plate and the displacement-transmitting plate with the cycle of color development. Alternatively, the contact time between the optical waveguide plate and the displacement-transmitting plate is controlled, while synchronizing the light emission time for the three primary colors with the color development cycle.
Therefore, in the display device proposed by the present applicant, it is unnecessary to use many picture elements, even if the display device is use to display the color image.
SUMMARY OF THE INVENTION
An object of the present invention is to improve the display device proposed by the present applicant and provide a reflective display device which makes it possible to simplify the arrangement for introducing the external light and/or the light from a light source, improve the luminance or brightness, improve the contrast, and improve the quality of a displayed image.
According to the present invention, a reflective display device comprises:
a display panel into which light is introduced;
a driving section disposed at the back of the display panel, the driving section including a plurality of actuator elements corresponding to a number of picture elements;
a picture element assembly provided on each of the actuator elements, the picture element assembly including at least a light-reflecting section and/or a light-absorbing section; and
a light-absorptive and/or a light-reflective substance filled between the display panel and the driving section,
wherein the actuator elements are selectively driven according to an attribute of an input image signal for controlling displacement of the picture element assembly in a direction closer to or away from the display panel, thereby adjusting degree of light-absorption and/or light reflection between the display panel and the picture element assembly so that a screen image corresponding to the image signal is displayed on the display panel. Preferably, the display panel is transparent.
Accordingly, the light from the external light or the light source is simply radiated onto the display panel, without introducing the external light or the light from the light source so that the light is totally reflected in the display panel. Therefore, it is possible to greatly simplify the arrangement for introducing the external light or the light from the light source.
Light emission is effected when a thickness of the light-absorptive substance between the display panel and the picture element assembly is decreased by displacing the picture element assembly in the direction closer to the display panel. Light emission is stopped when the thickness of the light-absorptive substance between the display panel and the picture element assembly is increased by displacing the picture element assembly in the direction away from the display panel.
Alternatively, light emission is stopped when a thickness of the light-reflective substance between the display panel and the picture element assembly is decreased by displacing the picture element assembly in the direction closer to the display panel. Light emission is effected when the thickness of the light-reflective substance between the display panel and the picture element assembly is increased by displacing the picture element assembly in the direction away from the display panel.
The picture element assembly may have a color layer. In this arrangement, the light-reflecting section and/or the light-absorbing section of the picture element assembly may serve as the color layer.
Further, for example, a three primary color filter, a complementary color filter, or a color scattering element may be used as the color layer. The “co
Akao Takayoshi
Nanataki Tsutomu
Shimogawa Natsumi
Takeuchi Yukihisa
Burr & Brown
Liang Regina
NGK Insulators Ltd.
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