Fusion Method For Spaced Conductive Element Window

Abstract

A display device in which a cathode ray tube envelope is utilized with a plurality of conductive elements extending from the interior surface of the faceplate of the cathode ray to the exterior surface of the cathode ray tube. A high resolution faceplate is provided by fabricating the faceplate in a manner such that the conductive elements are formed on a surface transverse to the inner and outer surfaces of the faceplate and this transverse surface is then formed into the faceplate to provide a vacuum type window.

Description

BACKGROUND OF THE INVENTION

This invention relates generally to a high resolution recorder utilizing an electron beam. The resolving power or data gathering capability of high resolution radar system is considerably better than the capability of the output or recording device. To match the capability of the radar system, a recording capability of 40 million resolution elements per square inch is needed. The conventional cathode ray tube which utilizes a phosphor screen provides a resolution of about one-half million elements per square inch. The resolution deficiency of the cathode ray tube is not due to the electron beam which can by careful gun design provide a resolution of about 650 million elements per square inch. The deficiency is also not caused by the recording medium, that is, the photographic film which is adjacent the phosphor screen. Degradation occurs in the phosphor layer which converts the electron energy into a light energy.

A phosphor layer consists of particles of from 1 to 5 microns in diameter and has a thickness of 30 to 50 microns. The light generated by the impinging electrons is reflected by the many particle surfaces and therefore the light emerging from the faceplate has been scattered laterally as well as forwardly. The spot of light seen by the viewer therefore is considerably larger than the size of the screen actually bombarded by the electrons. Furthermore, at high voltages, the electrons may penetrate more than one particle and suffer similar scattering. Degradation can, at some loss in efficiency, be reduced but not eliminated by using small particle sizes and the thinnest layer compatible with the electron penetration and manufacturing control.

In a cathode ray film recorder device, the electrical-to-light conversion is only an auxiliary function. The complete operation is the conversion of an electrical signal to blackening of a photographic film by a chemical reaction. By eliminating this auxiliary conversion and its inherent light scattering, better resolution is possible using instead one of the several methods of electrical photography. One process which is well known in the duplicating art is provided wherein an optical image by means of a photoelectric sheet is converted to an image of electrostatic charges which then control the distribution of a fine opaque powder. Another form of electrostatic recording is that in which an electron beam is utilized to deposit an electrical charge by means of embedded wires in a cathode ray tube. As the electron beam sweeps across the inner end of the rows of wires, the electrons are conducted through the wires to the outside of the tube where they are deposited on the surface of a dielectric coated paper. The paper is sandwiched between the face of the cathode ray tube and a grounded electrode. After the paper receives the electrostatic charge produced by the electron beam, the paper passes through a chamber where the image is developed with powder and then through a heat zone where the powder is fused to the paper. It is to this general type of system that the applicant's invention is directed and more particularly is directed to the means and methods of providing a high resolution system utilizing a large number of conductive elements between the inner surface of the faceplate and the outer surface of the faceplate to provide a high resolution conductive element faceplate.

SUMMARY OF THE INVENTION

An improved cathode ray tube including a faceplate having a plurality of electrical conductive elements passing through the faceplate and methods of manufacturing the tubes.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic showing of a system incorporating a high resolution cathode ray tube in accordance with the teachings of this invention;

FIG. 2 is an enlarged view of a portion of the faceplate of the cathode ray tube illustrated in FIG. 1;

FIG. 3 is an enlarged view of a portion of a faceplate that may be incorporated in FIG. 1; and

FIG. 4 illustrates another possible method of manufacture of a high density conductive element faceplate in accordance with the teachings of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, an electrostatic recording system is illustrated incorporating an improved cathode ray tube according to the teachings of this invention. The principal element in this system is the printing tube 10 which includes a cathode ray tube having a row 12 of closely spaced electrical conductive elements 14 extending from the inner surface of the faceplate 16 to the outer surface of the faceplate 16. The conductive elements 14 are insulated from each other. An electron gun 20 is provided in the neck portion of the cathode ray tube 10 and generates an electron beam which scans the row 12 of conductive elements 14 and electrons are conducted through the conductive elements 14 to the outside of the tube where they may be deposited on a dielectric coated film 24. The film 24 is sandwiched between the face 16 of the cathode ray tube 10 and a grounded electrode 26. The scanning speed of the electron beam in the cathode ray tube 10 is of such a speed that the film 24 may be moved continuously across the faceplate. After the film 24 receives the electrostatic image produced by the electron beam, it passes through a tone chamber 26. The tone chamber 26 provides a powder onto the film 24 which will adhere to the film 24 in accordance with the electric charge thereon. The film 24 then passes through an infrared fixture 28 which causes permanent adherence of the tone of powder to the film 24. The film 24 may be then fed into any optical processor 29. It is also desirable to recharge the film 24 prior to entering the region of the cathode ray tube 10. This may be accomplished by a corona discharge unit 30 which recharges the film 24 positively prior to the printing by the cathode ray tube 10.

In FIG. 2, a sectional view of a portion of the faceplate 16 is illustrated. The faceplate 16 may be manufactured by taking a faceplate and making a diagonal cut and forming two sections 37 and 39 to provide a transverse surface 40 on section 37. A suitable conductive coating of a material such as platinum may be deposited over the entire surface 40. The metal coating is then scribed crosswise to provide a plurality of conductive elements 14. The scribing may be accomplished by using optical grating equipment to provide the plurality of conductive elements 14. The present technology is capable of as many as 2,360 lines per mm. After scribing the metal coating into the row 14 of extremely fine conductors 14 along the transverse surface 40, the two sections 37 and 39 of the faceplate 16 are sealed together by a suitable sealing glass frit 41 to provide an integral vacuum tight faceplate.

Instead of scribing through a metal coating such as illustrated in FIG. 2, a grating may be scribed on the transverse surface 40 as illustrated in FIG. 3 to provide a V-groove 44. The transverse surface 40 may then be metallized with suitable conductive materials as that utilized in FIG. 2 and thereafter the surface ground down to remove all of the conductive coating except that portion 46 provided within the grooves 44. It is of course obvious that another technique of dividing of the metal coating is to utilize photoresist techniques instead of scribing.

To produce a faceplate with a full matrix of feed throughs across the entire surface, one possible technique is to provide a thin metal clad glass ribbon 50 which should be of a thickness equal to the line separation of the raster to be displayed on the CRT. It should also be manageable and of a width to provide adequate strength in the faceplate. As illustrated in FIG. 4, a roll of metal clad glass ribbon 50 is shown as item 52. The ribbon 50 includes a glass layer 51, a metal layer 53 and a photoresist layer 55. This roll of material is fed to a position where it is exposed by a projection source 54. The source 54 may include a mask to provide a plurality of strips of illumination as shown. The photoresist coating 55 on exposure to illumination from the projector 54 either causes the material to become soluble or insoluble when treated within a suitable etching chamber 56. After passing through the etching chamber 56, the metal clad ribbon 50 will have a plurality of conductive elements 59 as illustrated in FIG. 2 continuously along the tape 50. The tape 50 is wound into a roll 58 and the roll 58 will then be sealed in an oven to provide a vacuum tight window. The resulting block of insulating material 57 with the conductive elements 59 passing through may be sliced in any desired manner to provide a number of faceplates of desired thicknesses and diameter.

It is obvious that other methods and structures may be utilized within the teachings of this invention.

Claims

I claim:

1. The method of manufacturing a high density electrical conductive feed through vacuum tight window of insulating material having a plurality of spaced conductive elements extending through said window comprising the steps separating said window into a first and second portion, said first portion having a transverse surface to the inner and outer surface of said window, providing a coating of electrical conductive material on said transverse surface, removing portions of said conductive coating to provide said plurality of spaced conductive elements extending across said transverse surface between said inner and outer surface of said window and securing said first and second portion of said window together at said transverse surface to provide a vacuum tight window.

2. The method of manufacturing a high density electrical conductive feed through vacuum tight window of insulating material having a plurality of spaced conductive elements extending through said window comprising the steps of forming a tape of insulating material having a conductive coating on at least one side of said tape, removing portions of said conductive coating to provide said plurality of spaced conductive elements extending between the edges of said tape on one surface of said tape, winding said tape in a roll and then treating said roll to provide a vacuum tight window in which said edges of said tape provide the inner and outer surface of said window and said conductive elements extend between said inner and outer surfaces of said window.

3. The method set forth in claim 2 in which said conductive elements are provided on said tape by providing a conductive coating of material on at least one surface of said tape and coating said conductive coating with a photoresist material, exposing said conductive coating to radiations of a predetermined pattern and then removing selected portions of said photoresist material, etching away the exposed conductive coating and then removing the photoresist coating from the remaining conductive elements.

4. The method of manufacturing a high density electrical feed through vacuum tight window of insulating material having a plurality of spaced conductive elements extending through said window comprising the steps of separating said window into a first and second portion, said first portion having a transverse surface, providing a conductive coating on said transverse surface extending between the inner and outer surface of said window portion, removing selected portions of said conductive coating to provide said plurality of spaced conductive elements and sealing said first portion to said second portion of said window at said transverse surface to provide a vacuum tight window.

5. The method set forth in claim 4 in which said conductive elements are provided on said transverse surface by scribing away a portion of said transverse surface and providing a conductive coating over said transverse surface and then removing the conductive coating from the transverse surface other than the scribed portion thereof.

6. The method set forth in claim 4 in which said conductive elements are provided on said transverse surface by providing a conductive coating on said transverse surface and then scribing away portions of said conductive coating to provide said plurality of spaced conductive elements extending between said inner and outer surface of said window.