An electro-optical display system particularly for projecting an enlarged color television image on a screen in which the transmitted signals are converted into points of light modulated by a multiple Fabry-Perot interferometric or multiple electro-optical light modulator assembly.
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25. An optical system for separately and independently modulating or on-off switching light in each of a multiplicity of separately propagated light ray bundles, including
an arrangement of a multiplicity of fixed points of light each on a different part of a surface of a single body, each of said different parts being controlled separately electrically or electronically to modulate the point of light thereon, the disposition of the arrangement being such that light leaving each modulated point of light emerges at a preassigned one of a set of preselected separate positions propagated along a preassigned one of a set of preselected separate directions, optical means to receive light propagated from each modulated point of light of the arrangement and direct it to a prespecified one of a set of preselected separate locations, and an array of a multiplicity of optical fibers, each having an input region at which light can enter and be received, a region through or along which light can be propagated internally, and an output region from which light can emerge, the disposition of the array being such that the input region of each optical fiber of the array coincides with a preidentified one of the set of preselected separate locations and can receive light propagated from a preappointed modulated point of light of the arrangement through the optical means.
1. A display system for on-off switching or modulation of light separately and independently within each of a multiplicity of optical fibers, including
a source of light, a condensing system forming a small concentrated image of the light source, a first fiber optics assembly having the fibers closely packed and parallel to each other other at one end where light is received from the light source image and having the fibers separated from each other at the other end, forming a multiplicity of small points of light, a first optical system receiving light from the multiplicity of small points of light formed by the first fiber optics assembly and forming a multiplicity of small light point images, an array of light modulators within a single body each separately controlled electrically or electronically and each receiving light from one of the multiplicity of small light point images formed by the first optical system, a second optical system receiving light from the multiplicity of small points of light after modulation by the array of electrically or electronically controlled light modulators and forming a multiplicity of small light point images, a second fiber optics assembly having the fibers separated from each other at one end to receive light from modulated light point images formed by said second optical system and having the fibers adjacent to each other at the other end of the assembly forming a multiplicity of modulated points of light.
19. An optical system for separately and independently modulating or on-off switching light in each of a multiplicity of separately propagated light ray bundles, including
an array of a multiplicity of optical fibers, each having an input region at which light can enter and be received, a region through or along which light can be propagated internally, and an output region from which light can emerge, the disposition of the array being such that light can be directed into and received at the input region of each optical fiber and light leaving the output region of each optical fiber emerges at a predesignated one of a set of predetermined separate positions propagated along a predesignated one of a set of predetermined separate directions, optical means to receive light propagated from the output region of each optical fiber of the array and direct it to a prespecified one of a set of preselected separate locations, and an arrangement of a multiplicity of light modulators within a single body, each having an input region at which light can enter and be received, a region in which light can be modulated, and an output region from which modulated light can emerge, each light modulator of the arrangement being controlled separately electrically or electronically to modulate the received light, the disposition of the arrangement being such that the input region of each light modulator of the arrangement coincides with a preestablished one of the set of preselected separate locations and can receive light propagated from a prescribed optical fiber of the array through the optical means.
21. An optical system for separately and independently modulating or on-off switching light in each of a multiplicity of separately propagated light ray bundles, including
an arrangement of a multiplicity of light modulators within a single body, each having an input region at which light can enter and be received, a region in which light can be modulated, and an output region from which modulated light can emerge, each light modulator of the arrangement being controlled separately electrically or electronically to modulate the received light, the disposition of the arrangement being such that light can be directed into and received at the input region of each light modulator and light leaving the output region of each light modulator emerges at a preassigned one of a set of preselected separate positions propagated along a preassigned one of a set of preselected separate directions, optical means to receive light propagated from the output region of each light modulator of the arrangement and direct it to a prespecified one of a set of preselected separate locations, and an array of a multiplicity of optical fibers, each having an input region at which light can enter and be received, a region through or along which light can be propagated internally, and an output region from which light can emerge, the disposition of the array being such that the input region of each optical fiber of the array coincides with a preidentified one of the set of preselected separate locations and can receive light propagated from a preappointed light modulator of the arrangement through the optical means.
20. An optical system for separately and independently modulating or on-off switching light in each of a multiplicity of separately propagated light ray bundles, including
optical light source means, optical condensing means receiving light emitted by and propagated from the optical light source means and concentrating it within a set of predelineated small regions, an array of a multiplicity of optical fibers, each having an input region at which light can enter and be received, a region through or along which light can be propagated internally, and an output region from which light can emerge, the disposition of the array being such that light enters the input region of each optical fiber at one of the set of predelineated small regions and light leaving the output region of each optical fiber emerges at a predesignated one of a set of predetermined separate positions propagated along a predesignated one of a set of predetermined separate directions, optical means receiving light from the output region of each optical fiber of the array and directing it to a prespecified one of a set of preselected separate locations, and an arrangement of a multiplicity of light modulators within a single body, each having an input region at which light can enter and be received, a region in which light can be modulated, and an output region from which modulated light can emerge, each light modulator of the arrangement being controlled separately electrically or electronically to modulate the received light, the disposition of the arrangement being such that the input region of each light modulator of the arrangement coincides with a preestablished one of the set of preselected separate locations and receives light propagated from a prescribed optical fiber of the array through the optical means.
22. An optical system for separately and independently modulating or on-off switching light in each of a multiplicity of separately propagated light ray bundles, including
optical light source means, optical condensing means receiving light emitted by and propagated from the optical light source means and concentrating it within a set of predelineated small regions, an arrangement of a multiplicity of light modulators within a single body, each having an input region at which light can enter and be received, a region in which light can be modulated, and an output region from which modulated light can emerge, each light modulator of the arrangement being controlled separately electrically or electronically to modulate the received light, the disposition of the arrangement being such that light enters and is received at the input region of each light modulator at one of the set of predelineated small regions and light leaving the output region of each light modulator emerges at a preassigned one of a set of preselected separate positions propagated along a preassigned one of a set of preselected separate directions, optical means receiving light propagated from the output region of each light modulator of the arrangement and directing it to a prespecified one of a set of preselected separate locations, and an array of a multiplicity of optical fibers, each having an input region at which light can enter and be received, a region through or along which light can be propagated internally, and an output region from which light can emerge, the disposition of the array being such that the input region of each optical fiber of the array coincides with a preidentified one of the set of preselected separate locations and receives light propagated from a preappointed light modulator of the arrangement through the optical
means. 23. An optical system for separately and independently modulating or on-off switching light in each of a multiplicity of separately propagated light ray bundles, including
a first array of a multiplicity of optical fibers, each having an input region at which light can enter and be received, a region through or along which light can be propagated internally, and an output region from which light can emerge, the disposition of the first array being such that light can be directed into and received at the input region of each optical fiber and light leaving the output region of each optical fiber emerges at a predesignated one of a first set of predetermined separate positions propagated along a predesignated one of a first set of predetermined separate directions, first optical means to receive light propagated from the output region of each optical fiber of the first array and direct it to a prespecified one of a first set of preselected separate locations, an arrangement of a multiplicity of light modulators within a single body, each having an input region at which light can enter and be received, a region in which light can be modulated, and an output region from which modulated light can emerge, each light modulator of the arrangement being controlled separately electrically or electronically to modulate the received light, the disposition of the arrangement being such that the input region of each light modulator of the arrangement coincides with a preestablished one of the first set of preselected separate locations and can receive light propagated from a prescribed optical fiber in the first array through the first optical means, and light leaving each light modulator of the arrangement emerges at a preassigned one of a set of preselected separate positions propagated along a preassigned one of a set of preselected separate directions, second optical means to receive light propagated from the output region of each modulator of the arrangement and direct it to a prespecified one of a second set of preselected separate locations, and a second array of a multiplicity of optical fibers, each having an input region at which light can enter and be received, a region through or along which light can be propagated internally, and an output region from which light can emerge, the disposition of the second array being such that the input region of each optical fiber coincides with a preidentified one of the second set of preselected separate locations and can receive light propagated from a preappointed light modulator of the arrangement through the second optical means.
24. An optical system for separately and independently modulating or on-off switching light in each of a multiplicity of separately propagated light ray bundles, including
optical light source means, optical condensing means receiving light emitted by and propagated from the optical light source means and concentrating it within a set of predelineated small regions, a first array of a multiplicity of optical fibers, each having an input region at which light can enter and be received, a region through or along which light can be propagated internally, and an output region from which light can emerge, the disposition of the first array being such that light enters the input region of each optical fiber at one of the set of predelineated small regions and light leaving the output region of each optical fiber emerges at a predesignated one of a first set of predetermined separate positions propagated along a predesignated one of a first set of predetermined separate directions, first optical means receiving light propagated from the output region of each optical fiber of the first array and directing it to a prespecified one of a first set of preselected separate locations, an arrangement of a multiplicity of light modulators within a single body, each having an input region at which light can enter and be received, a region in which light can be modulated, and an output region from which modulated light can emerge, each light modulator of the arrangement being controlled separately electrically or electronically to modulated the received light, the disposition of the arrangement being such that the input region of each light modulator of the arrangement coincides with a preestablished one of the first set of preselected separate locations and receives light propagated from a prescribed optical fiber in the first array through the first optical means, and light leaving each light modulator of the arrangement emerges at a preassigned one of a set of preselected separate positions propagated along a preassigned one of a set of preselected separate directions, second optical means to receive light propagated from the output region of each modulator of the arrangement and direct it to a prespecified one of a second set of preselected separate locations, and a second array of a multiplicity of optical fibers, each having an input region at which light can enter and be received, a region through or along which light can be propagated internally, and an output region from which light can emerge, the disposition of the second array being such that the input region of each optical fiber coincides with a preidentified one of the second set of preselected separate locations and can receive light propagated from a preappointed light modulator of the arrangement through
the second optical means. 2. A display system according to
3. A display system according to
4. A display system according to
5. A display system according to
6. A display system according to
7. A display system according to
8. A display system according to
a body of electro-optic material of thickness small but finite compared to its length and breadth and with largest faces optically polished positioned between two polarizing elements to permit light transmitted by one polarizing element to enter and pass through the body of electro-optical material from one polished face to the other and thence through the other polarizing element, said optically polished faces of electro-optic material having affixed thereto arrays of electrodes positioned with respect to each other such that electrical potentials applied at predetermined points within the arrays will cause optical transmission of a multiplicity of separate small discrete volumes of electro-optic material to vary independently of each other according to the strength of the electric field applied to each.
9. A display system according to
10. A display system according to
11. A display system according to
the above described system duplicated twice to provide three duplicate light modulating systems forming three multiplicities of modulated points of light in identical straight lines and with red, green and blue filters respectively in the several systems, a dichroic set of mirrors combining optically said three identical straight lines of modulated points of light into one straight line of points of light each including separately modulated red, green and blue components, an electro-mechanical scanning and optical projection system to scan and enlarge optically said straight line of combined red, green and blue points of light across a viewing screen forming a large frame of 525 lines of colored points of light corresponding to the 525 lines in a television picture, and electrical and electronic means to receive and process a color television signal to provide appropriate control voltages to each separate electro-optic light modulator of the assembly and to provide appropriate synchronous control voltages to said electromechanical optical scanning and projection system.
12. A display system according to
13. A display system according to
14. A display system according to
the above described system duplicated twice to provide three duplicate light modulating systems forming three multiplicities of modulated points of light in identical straight lines and with red, green and blue filters respectively in the several systems, a dichroic set of mirrors combining optically said three identical straight lines of modulated points of light into one straight line of points of light each including separately modulated red, green and blue components, an electro-mechanical scanning and optical projection system to scan and enlarge optically said straight line of combined red, green and blue points of light across a viewing screen forming a large frame of 525 lines of colored points of light corresponding to the 525 lines in a television picture, and electrical and electronic means to receive and process a color television signal to provide appropriate control voltages to each separate electro-optic light modulator of the assembly and to provide appropriate synchronous control voltages to said electromechanical optical scanning and projection system.
15. A display system according to
16. A display system according to
the above described system duplicated twice to provide three duplicate light modulating systems forming three multiplicities of modulated points of light in identical straight lines and with red, green and blue filters respectively in the several systems, a dichroic set of mirrors combining optically said three identical straight lines of modulated points of light into one straight line of points of light each including separately modulated red, green and blue components, an electro-mechanical scanning and optical projection system to scan and enlarge optically said straight line of combined red, green and blue points of light across a viewing screen forming a large frame of 525 lines of colored points of light corresponding to the 525 lines in a television picture, and electrical and electronic means to receive and process a color television signal to provide appropriate control voltages to each separate electro-optic light modulator of the assembly and to provide appropriate synchronous control voltages to said electromechanical optical scanning and projection system.
17. A display system according to
18. A display system according to
the above described system duplicated twice to provide three duplicate light modulating systems forming three multiplicities of modulated points of light in identical straight lines and with red, green and blue filters respectively in the several systems, a dichroic set of mirrors combining optically said three identical straight lines of modulated points of light into one straight line of points of light each including separately modulated red, green and blue components, an electro-mechanical scanning and optical projection system to scan and enlarge optically said straight line of combined red, green and blue points of light across a viewing screen forming a large frame of 525 lines of colored points of light corresponding to the 525 lines in a television picture, and electrical and electronic means to receive and process a color television signal to provide appropriate control voltages to each separate light modulator of the assembly and to provide appropriate synchronous control voltages to said electromechanical optical scanning and projection system.
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This application is a continuation in part of my copending application Ser. No. 789,317 filed Jan. 6, 1969 now U.S. Pat. No. 3,567,847, issued Mar. 2, 1971.
The systems presently available for display of large color television images are too expensive for application to devices intended for use in the home. The systems now available for display of home color television images are limited in size, clarity and color quality of the displayed image.
An object of the present invention is to provide an improved system for display of color television images in the home.
An additional object of this invention is to provide in a display system means for simultaneous and independent modulation or on-off switching of a multiplicity of points or small areas of light.
This invention describes means to modulate a multiplicity of transmitted or reflected light beams by varying the positions of polished and coated optical surfaces in interferometric systems. Control over the position of each optical surface is maintained by locating the surface directly on electrostrictive material or by locating the surface on an optically workable material which is firmly attached to the electrostrictive material.
Interferometric modulation of light is well known in the present art and is described in terms of single beam modulation in U.S. Pat. No. 3,202,052 an in terms of multiple beam simultaneous modulation to provide an image formed interferometrically over an extended area in U.S. Pat. No. 3,100,817 and U.S. Pat. No. 3,233,040. There are certain practical difficulties in applying the teachings of the latter two U.S. patents which do not exist in devices utilizing the teachings of the invention described herein.
U.S. Pat. No. 3,100,817 and U.S. Pat. No. 3,233,040 each describe the use of thin sheets of electrostrictive material with the direction of electrical polarization perpendicular to the faces. Members of the barium titanate or lead zirconate family of piezoelectric ceramics are well suited for use in an interferometrically modulated system. The materials are hard enough to be optically worked to a flat surface and stable enough to hold their shapes after working. The electrical characteristics are also suitable for this application. For example in the case of one material a potential difference of about 625 volts provides a surface displacement of one quarter wavelength, the maximum required for full modulation. When sheets of piezoelectric ceramic are used to create a full frame interferometrically modulated image, it is desirable that they be as thin as feasible to provide maximum resolution. However, it is desirable that thickness be sufficient to prevent depolarization of the material with signal voltage. The polarizing voltage is 60 volts per mil of thickness. It is desirable that the signal voltage be below this value. Thus it is desirable that material thickness be greater than 11 mils and preferably greater than 30 mils.
These two requirements are in opposition to each other. U.S. Pat. No. 3,233,040 describes a thin sheet of electrostrictive material affixed to a glass-wire substrate having wires passing through the glass to permit electrical charges to be transmitted through the glass wall of a cathode ray tube. One commercially available glass-wire substrate has wires of 0.001 inch diameter spaced 0.004 inch center to center. Thus to take advantage of the resolution possible with this wire spacing it would be desirable to place a layer of electrostrictive material of about 0.002 inch thickness cemented to the glass-wire substrate. As noted before this is too thin a layer properly to accept an electrical signal of 625 volts. If a thicker layer of electrostrictive material is attached to the glass-wire matrix the resolution possible is determined by material thickness rather than by wire spacing.
In the following detailed description of this invention it will be shown that it is possible to retain high resolution while using thick electrostrictive material by separating immediately adjacent volumes of electrostrictive material with judiciously placed thin air spaces. Description will be given of embodiments of this concept in producible practicable devices capable of providing line-to-frame scanned television images in color.
Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered with the accompanying diagrammatic representational drawings wherein:
FIG. 1 shows a thick slab of piezoelectric material polarized through its thickness and a means for reducing the size of an area of surface which is displaced in response to an electrical potential applied to a point on the opposite surface.
FIG. 2 shows a disk of piezoelectric material configured to provide a multiplicity of independently controlled moveable elements.
FIG. 3 shows an assembly of the piezoelectric disk of FIG. 2 assembled to provide a multiplicity of independently controlled Fabry-Perot etalons.
FIG. 4 illustrates a Fabry-Perot etalon used to modulate a beam of collimated light.
FIG. 5 illustrates a Fabry-Perot etalon used to modulate a conical beam of light at is focus.
FIG. 6 shows the device of FIGS. 2 and 3 as utilized in a complete optical system to provide for display of a color television picture.
FIG. 1 represents a rectangle of piezoelectric material 1 of sufficient thickness to maintain dimensional stability. Upper surface 2 is a metallized surface of uniform potential. Lower surface 3 is an uncoated insulating surface. The material is polarized through its thickness. An electrical potential applied at a point such as 4 by wire 5 will create lines of electrical force in an approximately conically shaped pattern radiating from point 4 to an area 6 on surface 2 larger than the point 4 but small compared to the whole surface area 2. This region of electrical potential difference will cause the usual piezoelectric effect to occur. Thus small area 6 on surface 2 will be deformed slightly. The surface deformity can be made visible in an interferometric system.
A small volume of piezoelectric material 7 is attached to the main body of material 1 but is partially isolated from the main body 1 by air slots 8 and 9. The air slots serve two purposes. If an electrical potential is applied to point 10 by wire 11 the electrical lines of force will be contained within small volume 7 and will not penetrate through one-off on-off switching of a multiplicity of points or small areas of light using a multiplicity of Fabry-Perot interferometers, the application of this means in an optical system to provide modulation or on-off switching of light in a multiplicity of separate and discrete optical fibers arrayed with their exit ends forming a straight line, and a means for moving or scanning a line of modulated points of light to form an illuminated frame displaying a television picture.
The total system described may be characterized as a line-to-frame display system. The optical system illustrated in FIG. 6 includes a bank of electrically or electronically-controlled interferometric light modulators. The bank of interferometric light modulators is one means for simultaneously modulating or on-off switching of light in a multiplicity of points or small areas of light. It is not the only such means. The optical system shown in FIG. 6 will perform the same overall function if the bank of electrically or electronically-controlled interferometric light modulators is replaced by a bank of electrically or electronically-controlled electro-optic light modulators. Display systems have been constructed in which light transmission in small discrete areas of a larger area of electro-optic material is controlled by electronic signals to produce a full frame display of television pictures. A summary of development accomplished with systems of this kind is given in RCA REVIEW Volume 30, Number 4 of December 1969 on page 567 in an article entitled "A Reflex Electro-Optical Light Valve Television Display" written by D. H. Pritchard. This article describes assemblies in which light passes through each separately modulated volume of electro-optic material and upon emerging continues along its original direction of propagation. The article also describes assemblies in which light passes through each separately modulated volume of electro-optic material and is reflected back through the same volume thence emerging through the same face at which it entered but with its direction of propagation reversed. Thus points such as 54 in FIG. 6 at which light is illustrated as being reflected can be considered to be indicative of light impinging on a small discrete volume of transparent electro-optic material, passing through the volume, and being reflected back through and out through the entering face. More generally, then, points such as 54 in FIG. 6 can be considered to be single units in an array of light modulators within a single body each separately controlled electrically or electronically. Recently the technical literature has included references to control of electro-optical effects in small discrete volumes within a larger volume of electro-optical material by application of localized electrical potential differences through selected small volumes of the parent material with a grid of electrodes controlled by logic circuits. It is clear that the optical system shown in FIG. 6 will perform its function if light emanating from fiber ends such as 47 and striking modulating elements at points such as 54 is modulated interferometrically as previously described or electro-optically with an array of separate, discrete, and independently controlled electro-optic modulators, each within a larger parent body of electro-optic material, switched or modulated by an electron beam within a cathode ray tube or by an array of wires from an electronic logic circuit. In either case the optical system of FIG. 6 comprises a line-to-frame scanning system for the display of television pictures. As previously described three such systems can be combined to display television pictures in full color.
The basic optical system illustrated in FIG. 6 but not comprising all of FIG. 6 is a display system for one-off on-off switching or modulation of light separately and independently in each of a multiplicity of optical fibers. The configuration of fiber ends need not be limited to a straight line as shown at 59 in FIG. 6 but can have any desired configuration depending upon the application, which need not be limited to the display of television pictures.
My co-pending application Ser. No. 789,317 filed Jan. 6, 1969 emphasized the novel means for simultaneous and independent modulation or on-off switching of a multiplicity of points or small areas of light using a multiplicity of Fabry-Perot interferometers within a single body. The generalized optical system described therein is also considered to be a novel means for on-off switching or modulation of light separately and independently in each of a multiplicity of optical fibers. Specifically the generalized display system considered to be novel, fully described generically in my co-pending application Ser. No. 789,317, and illustrated in FIG. 6 comprises,
a source of light,
a condensing system forming a small concentrated image of the light source,
a first fiber optics assembly having the fibers closely packed and parallel to each other at one end where light is received from the light source image and having the fibers separated from each other at the other end, forming a multiplicity of small points of light,
a first optical system receiving light from the multiplicity of small points of light formed by the first fiber optics assembly and forming a multiplicity of small light point images,
an array of light modulators within a single body each separately controlled electrically or electronically and each receiving light from one of the multiplicity of small light point images formed by the first optical system,
a second optical system receiving light from the multiplicity of small points of light after modulation by the array of electrically or electronically controlled light modulators and forming a multiplicity of small light point images,
a second fiber optics assembly having the fibers separated from each other at one end to receive light from modulated light point images formed by said second optical system and having the fibers adjacent to each other at the other end of the assembly forming a multiplicity of modulated points of light.
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