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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is in the field of electro-optical imaging, and more
particularly relates to systems for converting electrical signals into
chromatic radiation for light-gate array decoding in a Flat Panel Display
(FPD).
2. Brief Description of the Prior Art
In the prior art, the color Cathode Ray Tube (CRT) has been universally
utilized for the conversion of electrical signals into monochromatic or
polychromatic images. Its versatility, however, is hampered by its
inherent characteristics of geometric distortion, package depth, high
voltages, lack of uniform resoultion, susceptibility to shock, gross
weight, and the apparent impracticality of achieving large (greater than
35 inches diagonal) or small (less than 2 inches diagonal) image surfaces
without projection or optical reduction, respectively.
Of recent interest is the co-called Flat Panel Display (FPD) as is noted in
commercial literature (1). This type of display is available today in
several varieties (2) known as Gas Plasma (GPD), Electrophorescent or
Electroluminescent (ELD), Vacuum Fluorescent (VFD), and Liquid Crystal
(LCD).
One prior art LCD, U.S. Pat. No. 4,090,219 (Ernstoff, et al), utilizes
sequential color field techniques, variable liquid crystal reflectivity,
and active electronics at each pixel site to achieve color imaging. Such
displays generally suffer from low image resolution due to slow pixel
response, narrow viewing angles, and video bandwidth degradation related
to sequential color field operation. System performance attainment is
further complicated by the mechanics of color filter switching, the use of
field-effect transistors and capacitors at each pixel site, and the
requirements for various video shift registers, electric latching, and
sample-hold circuitry.
Displays utilizing gas plasma (such as neon and argon ions) are in
widespread use, basically as monochrome or tone-on-tone devices. Voltages
to activate these gases are high (90-185 volts) compared to those utilized
in modern integrated circuitry (15 volts or less, typically). Image
refresh times employed (around 200 milliseconds) are considered too slow
for standard video. While these devices are relatively thin (3 inches) as
compared to the standard CRT, they suffer as the CRT from undersireable
weight and, as glass vacuum tubes, are shock-susceptible. Commercially
offered ELD and VFD devices, as with FPDs just discussed, have not been
shown to be viable alternatives to the color CRT; suffering generally from
a lack of orthochromaticity, with slow video response, low bandwidth, and
an inability to achieve broad gray-scale intensity shadings.
A method different from all of the foregoing is taught in U.S. Pat. No.
4,170,772 (Bly), wherein vertical strips of alternating red, green, and
blue phosphors are arranged across a common transparent front-plane
electrode and sandwiched between a plurality of horizontal back
electrodes. Upon application of the proper voltage(s) between some
horizontal electrode and the front-plane, the sandwiched phosphors are
caused to glow and appear as a series of red-green-blue dots repeated the
full length of the energized horizontal line. An electrobirefringent
light-valve (light-gate) column array, utilizing a type of PLZT Ceramic
material in a quadratic (Kerr Cell) format, is placed between the viewer
and the horizontal phosphor dot emissions through the front-plane, such
that the light-valve columns each address a phosphor dot. When the
columnar light-valves are caused to vary transmissivity in response to
video signals and while being properly sequenced, an image results.
Phosphor materials are generally not as responsive to steady state current
changes as they are to electron beam excitation under vacuum conditions
and short high voltage pulses. Further, degradation effects due to charge
migration when phosphors are excited by pulsed or steady-state D.C.
require alternation of applied voltage polarity periodically as an
alleviation; leading to additional switching means. Electrode spacing with
transverse (Quadratic) electro-birefringent materials also becomes
problematical when interfacing with peripheral drive circuit connections
for computer displays and the like. For instance, to provide for 10 volt
switching of PLZT Ceramic light-valve arrays, requiring 15,000 V/inch
(6,000 V/cm) between transverse electrodes, minute electrode spacing of
about 0.00067 inch (0.00170 cm) is required. The electrodes themselves,
when utilizing 15% of the spacing, would be only 0.0001 inch in width with
a density of 1,500 per inch. Accordingly, apart from small screen
scientific, military, or specialized industrial application, broad
utilization of PLZT modulated phosphor emission devices as color video
imagers has not materialized.
The instant invention contributes to the solution of many of the problems
found in the prior art as hereinbefore stated. Utilization of light
generators (such as the Laser or LED) to directly emit chromatic radiation
totally responsive to the video input signal(s) circumvents the need for
CRT electron beam means and the attendant large geometries and high
voltages. LEDs, in particular, allow for low video drive voltages (2-10
volts) while providing faster response (10 nanoseconds or less) than other
FPD methods discussed. Further, the invention does not possess the
complexities presented by active emitters and/or electronics at each pixel
site. Through the employment of linear birefringent materials such as
Lithium Niobate (LiNb03) in the light-gate decoder, reasonably accessible
electrode spacing of 0.008 inch is provided while good image resolution
(0.20mm pixel pitch) is maintained. A thin decoder (0.003 cm) utilizing
this material provides for optical switching with less than 10 volts.
As will be shown in the preferred embodiment of the invention, extensive
circuitry for latching, sample and hold, high voltage drive, and
FET-Capacitor pixel site control is not required. Configured in the
"solid-state", the embodiment comprises a thin, rugged and practical Flat
Panel Display with fast video response for either monochromatic or
multicolor imaging. Additional contributions to the art, through the
ability of the invention to radiate selectively at various output surface
points, enable multi-channel switched transmissions as may be employed for
signal multiplex/demultiplexing.
REFERENCES
(1) Periodicals:
"Video Signals and Monitor Design", Les Solomon, Dec. 1984 issue, Computers
& Electronics, Vol 22, No. 12, Page 53.
"Super - TVs", David Lachenbruch, July, 1985 issue, Popular Science, Vol
227, No. 1, Page 64.
"Flat Panel Display--Apple Computer", Cynthia E. Field, June 1985 issue,
inCider--The Apple II Journal, Vol. 3, No. 6, Page 95.
"Flat Panel Color TV", Carl Laron, Dec. 1984 issue, Radio-Electronics, Vol.
55, No. 12, Page 57.
"New Flat Panel Displays", Bob Margolin, Feb. 1985 issue, Computers &
Electronics, Vol. 23, No. 2, Page 66.
(2) Instructional Text:
Understanding Optronics, 1981, Masten, Masten, & Luecke, Texas Instruments
Learning Center, Dallas, TX Publ. Tandy Corp; Section 5, pp 14-27 incl.
SUMMARY OF THE INVENTION
In the method of the invention, electrical signals are encoded into a
non-coherent but unique field of optical radiation which is subsequently
decoded for coherent imaging. The invention is referred to by me as the
"Chromachron", thereby depicting its attributes of timing and
multi-chromaticity. The terms "optical", "hues", "radiation", and "light",
are intended to encompass all wavelengths of the electronmagnetic spectrum
from the microwave through the x-ray regions; including infrared, visible,
and ultraviolet radiations as appropriate to the use(s) of the present
invention.
In one embodiment of the invention, the concept rests in a plurality of
light sources (two or more) of different hues (two or more) which can
include white, being actuated as required to generate conceived different
radiant hues as desired within a three-dimensional confining space. Egress
of optical radiation from the space is only as provided by the opening of
a binary light-gate ("gate") within a group of otherwise closed "gates"
arrayed in matrix form within a specified output region of the confining
space designated the "Imaging screen". The "gates" within this matrix
array, referred to herein as the RyCx light-gates, essentially comprise
the imaging screen. In accord with signals instigating the hues, unique
"gates" are opened and closed at synchronized points and times by digital
actuation so as to provide output(s) through the imaging screen surface.
When utilized for TV type imaging, timing and refresh techniques may be
used so as to preclude visual flicker of the image mosaic, when it is
actually composed of rapidly moving points of various transmitted hues
over the entire display surface.
In another embodiment of the invention, radiant hues themselves are
trajected into the three-dimensional confining space; thereby precluding
the need for actuating light sources within the invention.
The use of Primary or Secondary colors of two or more hues is fundamental,
having been researched by Maxwell in 1861 for projecting three color (Red,
Green, and Blue) images in registry so as to perceive pictures of various
hues. Two color work was done by Hauron in 1895, and subsequent work with
two and three color combinations has been accomplished by others, notably
Fox and Hickey (1914), Troland (1926), Judd (1940), and Land (1959). In
the basic color sciences the CIE chromaticity diagram presents a graphic
view of multi-color mix responses, while for communication (Viz:
television, color computer monitors, etc.), NTSC chrominance guidelines
are often specified.
One fundamental object of the invention, among other objects stated herein,
is to provide a viable solid-state flat-panel display alternative to the
Cathode Ray Tube (CRT). Within the methods and means of the present
invention, such an alternative is realized in an apparatus more efficient
in imaging than the CRT; while being of substantially less weight and
volume.
Unlike the CRT, the present invention requires no high voltages and,
indeed, is operationally compatible with the low signal levels and
actuating voltages found in modern day computing and communication
circuitry.
Through the method and means of the invention, RGB base video electrical
signals (indicative of Red, Green, and Blue colors to be mixed in some
proportion for achieving some perceived hue of an image) are applied to
the transducers of an electro-optical converter; said converter being an
integral part of the encoder of the invention. The convertor, capable of
emitting the RGB colors upon excitation, converts the RGB electrical
signals directly into the discrete RGB optical radiations required.
It is of no consequence if the emissions from the transducers are of
coherent or non-coherent form, so long as the hues, intensity, and
duration of emissions are as prescribed by the instigating RGB signals.
Among the various types of electro-optical transducers known in the art to
be capable of the function(s) required, I have found the solid-state laser
or the LED (Light Emitting Diode) to be most fitting for the purpose. In
particular, the LED is utilized in a preferred embodiment of the
invention.
As prescribed hues radiate from the converter, they are caused to instantly
disperse throughout a radiation confining region within the encoder; the
"Ganzfeld Distributor". This ganzfeld (entire field) region is so
configured as to contain the available radiation in a unique "Ganzfeld
Radiation" form, such that the established field is not coherent in the
sense of collimation and wave/ray phasing, but is uniform as to hue and
field strength, i.e., isochroous and isotropic, within the ganzfield
distributor. Methods of the invention provide for the ganzfeld hue to be
achieved through either "black-level" or "white-level" base modes; wherein
discrete color emissions are, respectively, added or substracted. This
ganzfeld radiation possesses no discrete beam and permeates the
three-dimensional ganzfeld region as a radiant and uniformly perceived hue
having uniform intensity throughout. Totally contained, egress of this
radiation is only as allowed through a prescribed surface of the ganzfeld
distributor contiguous with the input to the imaging screen of the
invention. The ganzfeld distributor function may be enabled through
passive optical elements known in the art, with the transmissive
containment region being hollow, fluid filled (gas or liquid), solid,
granular, or a heterogeneous composite of the foregoing.
The established ganzfeld radiation totally and uniformly transilluminates
the imaging screen's input surface, which in a preferred embodiment
consists of a transmissive polarizer of film, sheet, or plate form. The
output surface of the imaging screen consists of a like polarizer oriented
orthogonally to the input polarizer such that one polarizer may pass only
vertically polarized light while the other may pass only horizontally
polarized light.
Between the two polarizers of the imaging screen resides a transmissive
plate (E-B plate) of electro-birefringent material of which several types
are known within the art. In a preferred embodiment, a thin Pockels effect
linear electro-birefringent material such as lithium niobate (LiNbO3) is
employed, having closely spaced transparent electrode lines on each of its
surfaces normal to the optical axis. The electrode lines of one side of
the E-B plate are disposed orthogonally with respect to the electrode
lines of the other side. This composite configuration, viz., two
orthogonally disposed polarizers sandwiching an E-B plate having
orthogonal electrode lines upon its surface contiguous with the
polarizers, comprises an electro-optical light-gate as is known in the
art. Further, as there is a plurality of orthogonally disposed electrode
lines, a matrix arrayed plexus of minute light-gates (the RyCx gates)
comprising the imaging screen of the invention is formed. Voltages applied
to the electrode lines activate the light-gates.
This configuration may be visualized as a x-y matrix coordinate system with
electrodes being the x and y lines of a tick-tack-toe or checkerboard
arrangement wherein the checkerboard-like squares are individually
switchable light-gates or "windows" which may be either opened or closed
to optical transmissions. It may be further visualized that, should the
various hues of an image be transmitted through these "windows" in proper
association, a color image mosaic will be perceived; or a monochromatic
image perceived should transmissions be of the same hue with intensity
shadings.
In the method of switching the light-gates for hue transmission, x-y
electrodes are addressed with actuating voltages in a prescribed manner.
Such addressing causes a "window" or "windows" (gates) to be opened within
the imaging screen light-gate array so as to dictate the time and place
within the image mosaic being transmitted that a unique hue, prescribed by
some unique RGB signal actuating the system of the invention, emanates as
a spot-transmission. The entire light-gate array is scanned, as to space
and time, in accordance with RGB signals being applied to the system;
thereby rendering the image mosaic as multiple unique spot-transmissions
of the prescribed hue(s) through the imaging screen.
Optical radiations derived and switched through the methods and means of
the invention have applications within the electro-optic arts other than
the imaging of scenes. By coupling the ouput of the imaging screen of the
invention appropriately to the input of electro-optical image converting
means, such as a CCD (Charge Coupled Device) video camera or other
iconoscopic device, radiation emanating from the imaging screen may be
converted to analogous electrical signals for storage, demultiplexing, or
re-transmission. Further, by coupling fiber-optic or other
receptive-transmissive elements to the imaging screen light-gates, the
discrete radiant spot-transmission(s) provided through the transmissive
elements may be utilized for remote display of scenes or
spot-transmissions; or converted to electrical analogs of the chromatic
constituents; or distributed throughout a multitude of receptive channels
such as would comprise an optical switching or optical demultiplexing
system.
Means and methods of the invention may also be applied to multiplexing
within electro-optical systems. Conversion of discrete or multiple RGB
electrical signals into the ganzfeld type of optical radiation, possessing
uniform hue and field strength characteristics, effectively comprises
electro-optical multiplexing. Further, the direct conversion of discrete
or multiple optically radiant hues, themselves, into the aforesaid
ganzfeld type of radiation comprises direct optical multiplexing.
It is thus an object of the present invention to provide apparatus and
methods advantageous to the art of color imaging and electro-optical
switching.
Another object is to provide means for encoding electrical video color
signals directly into generated chromatic radiation with hues responsive
to the input video signals.
Another object is to provide method and means for achieving a uniformly
encoded radiant optical field directly from a discrete radiant hue, or
multiple radiant hues, possessing constituents to be encoded.
Another object is to provide containment, processing and directing means
wherein the entire field of radiation generated is substantially coupled
to the input of a decoder imaging screen.
Another object is to provide means for electro-optically decoding the
encoded radiation to achieve the imaging of scenes or decoded
spot-transmission(s).
Another object of the present invention is to present means whereby any
portion of a surface illuminated by the encoded radiation contains the
same instant intelligence.
Another object of the subject invention is to provide for simultaneously
identical multi-imaging within the confines of a decoder imaging screen
transilluminated by the radiation generated.
Another object is to provide means and apparatus for multiplying and
demultiplexing signals in communications and logic systems.
Another object is to provide an imaging device compatible with computer and
telecommunication signal levels and formats.
Another object of the invention is to provide a flat panel display that, in
comparison to the color cathode ray tube of the prior art, has the
attributes and advantages of thin cross-section, solid-state construction,
reliability, low power consumption, and light weight.
A preferred embodiment of the instant invention provides for the direct
conversion of electrical video signals into imaging hues.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic block diagram illustrating the system of the present
invention;
FIG. 2 is a schematic block diagram of the decoder comprising imaging
screen and digital driving means;
FIG. 3 is a view of the Chromachron assembly;
FIG. 3A is a side elevation of the Chromachron assembly;
FIG. 4 is a sectional view taken along the line 4--4 in FIG. 3;
FIG. 5 is a view of the converter means of the invention;
FIG. 5A is a side elevation of the converter means of the invention;
FIG. 6 is a side elevation of the imaging screen assembly;
FIG. 6A is an elevation view of the imaging screen output surface;
FIG. 6B is an elevation view of the imaging screen input surface;
FIG. 7 is an exploded perspective view of the chromachron device;
FIG. 8 is a view of another embodiment showing a simple housing defining
the distributor means;
FIG. 9 is a view of another embodiment of the distributor or means defined
as a mix of dispersive particles contained in a simple housing;
FIG. 10 is a view of the preferred embodiment of the distributor means
shown as a solid transmissive refractive-dispersive substance;
FIG. 11 is an optical emission timing diagram for obtaining chromatic
ganzfeld radiation with the invention operating in a black-level reference
mode;
FIG. 12 is an optical emission timing diagram for obtaining chromatic
ganzfeld radiation with the invention operating in a white-level reference
mode;
FIG. 13 is a partial sectional view of the Chromachron device depicting
transmissive optical guides coupled to the imaging screen;
FIG. 14 is a partial sectional view of the Chromachron device depicting
spot-transmission(s) detected by photo-electrical means;
FIG. 15 is a view of another embodiment of the distributor means shown as
passive optical processing means having coupled light-guide means for
intertrajection of optical signals; and
FIG. 16 is a line drawing of an imaging cube depicting multiple imaging
screens providing multiple images from the same instant gansfeld radiation
field.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Through the methods and means hereinafter detailed, derived and processed
fields of video analog optical radiation are directed to transmit
selectively as chromatic pixels; thereby obviating the need for phosphors
and electron beams as in the CRT.
Referring now to FIG. 1 of the invention, instant electrical video RGB
signals 1 (signals 1), in synchronization with horizontal and vertical
sync signals 27, are converted through polychromatic converter means 3 to
derive instant optical emissions 5, whose radiation is to be processed and
directed for imaging or transmission as a pixel or beam.
Emissions 5 are dispersively processed through ganzfeld (entire field)
distributor means 7 of encoder means 11 to become established therein as a
constrained and isochroously perceived instant isotropic optical radiation
field 9 (field 9), the perceived hue of which is derived by chromatic
mixing in a fashion not unlike the samplings or FIG. 11 of FIG. 12.
Field 9 is of the ganzfeld isotropic form, with instant intensity,
persistence and isochroous hue (uniform color throughout) being the
synergistic optical resultant of the tri-stimulus constituent values of
signals 1. Field 9 instantaneously resides in and permeates the
three-dimensional region of encoder means 11 conjoining decoder means 13
so as to totally and uniformly transilluminate electro-optical imaging
screen means 21, said screen means 21 comprising a contiguous plurality of
binary light gate RyCx imaging points to be herein later described.
An instantaneously unique RyCx light-gate imaging point is synchronously
selected and actuated by address controller means 23 so as to direct a
ganzfeld transmission of the total resident radiation field 9 through said
unique RyCx light-gate imaging point of screen means 21 as an imaged
optical pixel or radiant beam. Reiterative processing through the
foregoing methods and means for each subsequently instant signals 1
provides subsequently instant ganzfeld transmissions of fields 9 through
screen 21 as properly timed and spatially oriented contiguous pixels of an
optical composition being imaged. Continuous reiteration, or "refreshing"
as is known in the art, provides for veridical (true, accurate) imaging
without perception of visual flicker.
Supplementing this description with FIG. 2 and FIG. 7 now, decoding
method(s) to timely select and actuate a RyCx light-gate imaging point of
screen 21, so as to image an instantaneously resident field 9 which is the
optical radiation analog of an instant RGB signals 1, will be discussed:
Address controller means 23, to be herein later described, accommodated by
system power means 25, and synchronized by sync signals 27, activates row
address lines 17 and column address lines 19 for the purpose of
electro-optical switching within imaging screen 21, said screen 21
comprising a contiguous plurality of selectively transmissive binary
light-gates (RyCx gates) arrayed in matrix form and serving as imaging
points for directed ganzfeld transmission(s) of radiation field(s) 9 as
pixels or beams.
Lines 17 and lines 19 respectively actuate row electrodes 39 and column
electrodes 41 of screen 21 with appropriate voltage(s) from controller
means 23 so as to enable a synchronously selected opening of a unique E/O
(Electro-optical) binary gate RyCx from its remanent closed state. An
"open" gate RyCx allows radiation to transmit while a "closed" gate RyCx
does not. This unique open light-gate RyCx is selected from among an
available plurality of otherwise closed light-gates RyCx arrayed in a
row/column (Y/X) imaging matrix format. The radiation input for gates RyCx
is input polarizer 47 of screen 21 and the radiation output for gates RyCx
is output polarizer 51 of screen 21.
Realize, that from foregoing processes, the unique open gate RyCx is
instantly synchronized with the resident optical analog radiation field 9,
which is instantly synchronized with RGB signals 1. Realize further, that
this field 9 pervades the distributor means 7 section of encoder 11, and
contiguously coupled the input of screen 21. And, through the methods and
means of the present invention, field 9 is contrived to totally,
uniformly, and simultaneously transilluminate the input to all gates RyCx
comprising the imaging matrix array of screen 21, but may transmit through
screen 21 at an "open" RyCx gate only.
Accordingly, the entire instant radiation field 9 transmits only as
directed by controller 23 through the instantly unique open light-gate
RyCx of screen 21 as the spot-transmission hue 15. Thus derived, processed
and directed, hue 15 is a unique chromatic isochroously perceived beam of
said radiation or unique radiant pixel; with said beam (or pixel)
possessing all the attributes, including temporal and spatial resolve,
attendant to its instigating RGB signal 1; and may be further perceived as
one of the pixels of a scene being imaged. Further, hue 15 may be utilized
as a discrete optical signal for other applications of the invention to be
herein later described.
Elements 1 through 29 of FIG. 1 comprise an embodiment of the operating
system of the invention.
Parts 3 through 23 of FIG. 1 comprise the apparatus 29 of the invention.
Parts 3 through 7 of FIG. 1 comprise components of the encoder 11 of the
invention.
Parts 17 through 23 of FIG. 1 comprise components of the decoder 13 of the
invention.
Elements of the converter means 3, the distributor means 7, the screen 21,
the address controller means 23, and other means or methods not found in
foregoing descriptions will be hereinafter detailed.
RGB signals 1 are electrical signals indicative of the Red, Green, and Blue
optical content to be established in the radiation field 9, and possess
the analog attributes of amplitude and duration proportional to a related
optical constituents's contribution to the field 9. As presently practical
video cameras and picture tubes pick up and display only luminance based
information, a TV camera resolves a color scene into red, green, and blue
separation images focused on three respective camera tubes. Output
voltages Er, Eg, and Eb of these tubes, being proportional to the
intensities of the three color primaries, are processed into a "composite
video" form (PAL or NTSC) for RF carrier modulation.
RGB signals 1, to be provided to converter means 3 of the invention, are of
the camera output form (Er, Eg, Eb), and not of the "composite video"
form; and are referred to herein as the "RGB" or "base video" form, being
synchronously associated with sync signals 27.
Synchronization of the interrelated processes of the invention, wherein
base video signals 1 are encoded by encoder 11 into fields 9 for
transmissions through screen 21 as hues 15, is provided by the application
of sync signals 27 to address controller means 23. The utilization of
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