US3826867A

US3826867A - High-sensitivity beam-index and heaterless cathode ray tubes

Info

Publication number: US3826867A
Application number: US00345197A
Authority: US
Inventors: D Goodman
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-07-26
Filing date: 1964-02-17
Publication date: 1974-07-30
Anticipated expiration: 1991-07-30
Also published as: NL6506890A; DE1437668A1; US3967315A; FR1453888A; GB1047953A; US3567985A

Abstract

Improvements are set forth for generating and detecting index signals which indicate the position of a scanning beam on a target screen. Light pipe-scintillator combinations are disposed about the target screen, the funnel section and the electron gun section of beam-index and multicolor cathode ray tubes. Multiple configurations of optical fibers, hollow cylinders and funnels collect, transform, and concentrate electromagnetic radiation, index signals, and derivates thereof. Light pipe-scintillator configurations used with the target screen transmit optical signals from different regions of the target screen to its periphery. Scanning of the target screen by light beams is also described.

Description

Unites Goodman ates .1 tet [191 [451 Ju1y30,1974

1 1 HIGH-SENSITIVTTY BEAM-INDEX AND HEATERLESS CATHODE RAY TUBES [21] Appl. No.: 345,197

Related US. Application Data [63] Continuation-impart of Ser. No. 212,612, July 26,

[52] US. Cl 178/5.4 F, 313/82 R, 313/92 Bl, 313/110, 315/21 R [51] Int. Cl. H04n 9/24 [58] Field of Search 313/65, 92; 250/715, 227; 88/1; 178/D1G. 2, 5.4; 346/110; 315/104 [56] References Cited UNlTED STATES PATENTS 2,749,449 6/1956 Bradley ct al 313/65 2,765,411 10/1956 Kerr 1 250/227 2,915,659 12/1959 Goodman 313/65 3,027,219 3/1962 Bradley 313/92 3.081.414 3/1963 Goodman 313/65 3,198,881 8/1965 Knocklein 313/92 3,225,193 12/1965 Hilton et a1 250/227 3,234,329 2/1966 Eisner 250/227 3,265,892 8/1966 Sheldon 250/715 3,294,903 12/1966 Goldmark et a1 178/68 Primary ExaminerRobert Segal Assistant ExaminerRichard A. Rosenberger 5 7 ABSTRACT Improvements are set forth for generating and detecting index signals which indicate the position of a scanning beam on a target screen. Light pipe-scintillator combinations are disposed about the target screen, the funnel section and the electron gun section of beamindex and multicolor cathode ray tubes. Multiple configurations of optical fibers, hollow cylinders and funnels collect, transform, and concentrate electromagnetic radiation, index signals, and derivates thereof. Light pipe-scintillator configurations used with the target screen transmit optical signals from different regions of the target screen to its periphery. Scanning of the target screen by light beams is also described.

43 Claims, 21 Drawing Figures ggmgmumlm SHEEY 1 0F 3 INVENTOR.

04 140 M, GOODMAN AT TORNEYS PAFENTED 3,886.86?

sum

2 or 3 IN VENTOR.

DA V/D M GOODMAN 4122M FIG. l3 d" A 1- TORNE YS HIGH-SENSITIVITY BEAM-INDEX AND HEATERLESS CATHODE RAY TUBES This application is a continuation-in-part of Applicants then copending application Ser. No. 212,612 filed July 26, 1962, which was refiled as continuation application Ser. No. 562,031 on June 2, 1966, now Pat. No. 3,567,985 issued on Mar. 2, 1971.

This invention relates to cathode ray tubes; it relates to improvments in the pick-up of electromagnetic radiation type signals; and it relates to a new technique for generating high speed electromagnetic index signals.

Cathode ray tubes for some time have been described and built which have target screens that generate index signals in response to electron beam bombardment. These index signals signify the point or region (i.e., the position) of impact of the electron beam upon the target screen. Many forms of circuits have been described and built which take advantage of these index signals to control the electron beam. It is now known that to generate these electron beam position locating index signals it is possible to use:

l. electron conduction currents from a wire grid 2. secondary electron emission from a wire or metallic grid 3. electromagnetic radiation in the optical frequency range (which embraces the infrared and ultraviolet) 4. X-ray index signals.

The latter two methods of deriving index signals have definite advantages in that the radiation signals travel at the speed of light, and in that they require no circuits to be connected to the target screen. The X-ray index signals have the additional advantages of (1) being rapid in both response and decay and (2) in extending over a wide region of the electromagnetic spectrum.

In certain designs embodying these optical or X-ray indexing features it becomes desirable to provide the index signals even when the electron beam is set at low current levels. It has also been disclosed, in my copending application Ser. No. 212,612 filed July 26, 1962 which is incorporated herein by reference, that with sufficient collection of the electromagnetic radiation which emanates from a target anode it is possible to eliminate the conventional heated cathode of electron discharge devices.

It is therefor an object of this invention to provide simple and inexpensive means which increase the sensitivity of pick-up of electromagnetic type signals emanating from target screens or anodes in discharge devices.

And another object of this invention is to provide new and different target screens for cathode ray tubes which will not require the electromagnetic index signals generated thereat to be radiated through a large volume of space prior to pick-up.

Still another object of this invention is to provide new and different wavechangers which pick up electromagnetic radiation, convert same to a lower frequency, and which transmit the lower frequency radiation in a more compact form.

Still another object of this invention is to provide simple and inexpensive index signal pick-up means for color cathode ray tubes.

Briefly stated, the first of these objectives is achieved by providing a thin, specially shaped detector (or receiver) which is suitably positioned with respect to the cathode ray tube (CRT). This detector (or receiver) is shaped to conform to the dimensions of the envelope of the CRT, and is positioned to have a large area exposed to the index radiation, and is dcsigned to be readily mass produced.

The second objective is achieved by providing thin light pipes, or optical fibers, interspersed with or closely adjacent the target screen so that the indexing radiation is derived directly from impact of the electron beam upon the optical fibers.

The numerous advantages and benefits to be derived from these arrangements, and the manner in which the other objects of this invention are achieved, will be explained by referring to the following description of the invention taken in conjunction with the accompanying drawing wherein:

FIG. 1 represents a side view of the conical envelope of a CRT with a specially shaped light pipe member surrounding the envelope.

FIG. 2 represents a sectional view of the specially shaped light conducting member in FIG. 1.

FIG. 3 represents an end view of the CRT assembly in FIG. 1.

FIG. 4 represents a section, or end view, of the compact exit termination of the light pipe member.

FIG. 5 represents a development of the special light pipe member of FIG. 1.

FIG. 6 represents an end view of a compact termination akin to FIG. 4 but with a circular-like exit.

FIG. 7 represents a sectional view, akin to FIG. 2, of a special member having an exit termination as depicted in FIG. 6.

FIG. 8 represents a sectional view of a CRT with a light pipe shroud surrounding both the conical envelope and the faceplate.

FIG. 9 represents a CRT akin to FIG. 8 but with a hood extending beyond the faceplate.

FIG. 10 is a sectional view of a CRT with a series of specially shaped, internally disposed light pipe members.

FIG. 11 is a partial section of a CRT with an internally disposed X-ray transparent member.

FIG. 12 represents a CRT with a special target screen embodying optical fibers.

FIG. 13 represents a partial cross-section of the envelope of the CRT in FIG. 12 and shows the optical fibers leading from the target screen to the neck section of the CRT.

FIG. 14 represents an end view of the CRT in FIG. 12 and shows the optical fibers of FIG. 13 as they emerge from the neck of the tube.

FIG. 15 represents a target screen containing red, green, and blue color emitting regions and fiber optic index elements.

FIG. 16 represents a target screen with different color emitting regions separated by two different sets of fiber optic index elements.

FIG. 17 represents a cross-section of a target screen with red, green, and blue color emitting phosphors and with an optical fiber, or light pipe, deposited on a faceplate.

FIG. 18 represents a target screen akin to that in FIG. 17 but with the light pipes placed against the phosphors.

FIG. 19 represents a CRT wherein the electromagnetic index signal are transmitted through the envelope portion of the tube.

FIG. 20 represents a sectional view of the faceplate of the CRT in FIG. 19 wherein the scintillating elements are deposited on or sintered into the faceplate.

FIG. 21 is a front view of a typical target screen shown sectioned in FIG. 20.

In FIG. 1, the envelope of a CRT is contained within a jacket 12, which in turn is covered by a thin layer 14. Typically, the envelope consists ofa neck section 16, an intermediate section 18, and a faceplate 20. It will be assumed for descriptive purposes that the neck section is cyclindrical, the intermediate section is conical, and that the faceplate is either spherical or planar; although it is manifest that other shapes can be used. The jacket 12, made ofa plastic light pipe scintillator, emits light in the optical frequency range when bombarded by radiation emitted from a target screen associated with faceplate 20. This emitted radiation preferably is in the X-ray or ultra-violet region of the spectrum, and layer 14 is chosen to be reflective of this radiation. The light generated by scintillation in the plastic jacket 12 is trapped therein, towards which end the reflective layer 14 may assist, and is transmitted by a series of internal reflections to the strip-like elements 22. The longitudinal cuts 24 separate the strips 22 in order that their ends may be brought together as at 26. A mating section of light pipe 28 may be used to couple the transmitted light to another section of light pipe, or it may be used to project the scintillations onto a suitable photo-sensitive device. By virtue of this particular construction, an enlarged conical area of the jacket 12 is exposed to the radiation emanating from the target screen of the faceplate 20. The arrangement of this FIG. 1 stems from the teachings of my previously mentioned application Ser. No. 212,612. The instant arrangement, however, is advantageous in that the jacet 12 may be made from a single article of manufacture. This will become more clear from the description of FIGS. 2-10.

In FIG. 2, which is a cross-section of FIG. 1 taken through the cut 22, strip-like elements 22 are shown positioned about the glass neck section 16 of the CRT. Outer layer 14 is shown to surround the jacket 12 which is comprised at this point of strip-like elements 22. The layer 14 can terminate at this region of the jacket, or it may be extended towards the exit region 26 in which case the cuts or slits 24 are made to extend through both the jacket 12 and the layer 14.

FIG. 3 illustrates an end view of the exit termination 26, which is made of the strips 22 brought together in the shape of a square. The neck section of the CRT is designated 16 and corresponds to like designations in FIGS. 1 and 2. In FIG. 4, an enlarged view of the exit 26 is illustrated. There are twelve strip-like elements 22. Each strip has dimensions of a x a/l2 so that the overall dimensions of the exit termination is a x a.

The advantage to be gained from the construction of the jacket just described with reference to FIGS. 1-4 is made clear from the developed view illustrated in FIG. 5 where it is shown that jacket 12 may be manufactured from a single flat piece of scintillator material.

Alternate configuration of the exit termination 26 is shown in FIG. 6 where the outside dimensions conform more or less to that of a circle. The view in FIG. 7 shows how the strips 22' are arranged in varying widths for this purpose. The ultimate choice of the shape of exit 26 will be governed in most cases either by the shape and size of the photo-sensitive element of the adjoining photon detector of which there is a great variety, or by the shape and size of the mating light pipe member 28 shown in. FIG. 1.

In FIG. 8, the CRT envelope 10 has ajacket 12 which may be formed by molding a plastic scintallator about the tube envelope. In this case the plastic can extend over the faceplate, as shown at 15, to provide mechanical protection akin to the so-called bonded faceplates which are now in widespread use. The plastic jacket can also be assembled to the CRT envelope without the molding process if the jacket is pre-fabricated in two sections. The two sections can be made to join along a cut through the longitudinal axis of the structure, or the jacket can be split transversely of its axis along the ringlike region 13. A coupling or transition light pipe element, akin to that shown to the left of section 2-2 in FIG. 1, is contemplated to mate with the hollow cylindrical termination. This is also the case with regards to FIGS. 9, 10, 11, 12, and 20 where the scintillations to be detected are also transmitted via a thin walled hollow light pipe.

In FIG. 9, the tube envelope 10 is surrounded by the scintillator jacket 12, and the reflective layer 14, but in this case the scintillator is projected forward to form a hood or shield 17 about the faceplate 20. This concludes the description of the externally disposed large area scintillators except to note that many of the glasses useable as CRT envelopes will transmit in the ultraviolet, and therefore the arrangements disclosed contemplate the use of electromagnetic radiation in the optical frequency range as well as X-rays.

In FIG. 10, a CRT for color television receivers has an envelope with a neck section 30, an intermediate section 32, and a faceplate 34. A target screen 36 deposited on the faceplate is of the index type and therefor may be thought of to contain red, green and blue phosphors and indexing strips. An electron gun is shown at 38. Further descriptive details are believed unnecessary for these components of index type color CRTs are very well known. The electromagnetic index radiation, which emanates from the target screen in response to bombardment by the scanning beam of cathode rays provided by the electron gun, spreads out into the interior region of the CRT. To pick up this index radiation, a funnel shaped light pipe member 40 is positioned within the envelope of the CRT.

Funnel 40 is shaped to conform to the general shape of the tube envelope at both the neck section 30 and intermediate section 32 of the CRT. The funnel is made in one piece. To allow its assembly into the CRT, the faceplate 34.is frit-sealed to the intermediate section 32 at the ring junction designated 42. If the frit-seal is deemed undesirable, the light pipe member may be limited in shape to the cylinder 44 which terminates in the vicinity of angular ring 46. Made in this way the light pipe 44 can be assembled with the electron gun 38. In any event, it can be appreciated from the drawing that cylinder 44, whether alone or as part of funnel 40, is a hollow thin light pipe member positioned to fit between the electron gun 38 and the neck 30 of the CRT. The optical signals transmitted through cylinder 44 pass through the neck at 48 to be picked up by transition or coupling element 50. The design of this transition element 50 follows from the description of FIGS. 1-7 and it should also be noted that the electrical connections to pins 52 can be routed through the opening in the light pipe transition.

The optical signals which are to be transmitted through the cylindrical light pipe 44 may be picked up in a manner of ways. First: The index radiation from target screen 36 may enter the light pipe by impinging directly upon an entrance port. This may happen at ring 47 for a cylindrical member; or at ring 55 for a shortened funnel shaped member ending at 54; or at entrance ring 56 which is flared inward and positioned to face the target screen 36. Second: The index radiation may enter directly via the large area interior surface of funnel 40. This may happen if the surface is serrated, notched, etched, or dimpled in accordance with known techniques. Third: The index radiation may penetrate the funnel 40 and create scintillations therein which will be transmitted by light piping action. For the first or second mode of pick-up, the

cuts

46 or 54, the ring 56, or the interior surface of funnel 40 may also be coated with a scintillator sensitive to the index radiation. For the third mode of pick-up, the funnel 40 may be coated with a thin light reflecting layer such as aluminum or aluminum oxide to enhance the light piping action. Thus, the light pipe may act as a receiver where it transmits the radiation in the same form as the index radiation, or it may act as a detector (wavechanger) where the radiation transmitted is at a different frequency from that of the inpinging index radiation.

Before leaving FIG. 10, it is to be noted that the funnel shaped interior configuration of the light pipe member 40 can also be used for the heaterless cathode ray tube described in my referenced application Ser. No. 212,612. Accordingly, the light pipe transition 50 can be made re-entrant so that the compact exit termination thereof goes back into the envelope of the CRT; optical gain or attenuation can be inserted seriatum; and the entire transition 50 can be disposed within the envelope of the CRT. Also, note projections 58 are used to separate slightly the funnel from the interior surface of the envelope to reduce light losses and note that a second concentric funnel a portion of which is shown at 60 may be used, with suitable filters, to provide a second index signal. This second index signal is transmitted through the CRT by light pipe means concentric with and having the same shape as cylinder 44 and transition 50. Although not shown, projections akin to 58 would be used to isolate adjacent funnels.

In FIG. 11, a special funnel 61 is positioned within a CRT. First funnel segment 61 and second segment 62 are made of metal and sealed to be vacuum tight at junction 64. The space between

segments

61 and 62 is provided in order to be filled with a liquid X-ray responsive scintillator. There are ring seals at 66 and 67 in the header of the CRT to preserve the vacuum therein. Glass disc 68 seals off the interior hollow opening of the funnel. For the arrangement shown this seal need not be vacuum tight. Light pipe 70 transmits the scintillations as required. This arrangement is useful when it is desired to use organic liquid scintillators which cannot tolerate the processing temperatures of the CRT, approximately 400C. The innersegment 62 of the funnel preferably is made of beryllium which is highly transmissive of X-rays. Stiffening rings, not shown, can be used when it is desired to use very thin segments for the funnel.

In FIG. 12, an arrangement is illustrated which even further increases the amount of index radiation picked up. This is achieved by bringing the light pipes into juxtaposition, so to speak, with the elements that actually emit the electromagnetic radiation index signal. By so doing that portion of the index signal which is lost due to poor geometry is lessened. Thus, the CRT of FIG. 12

has a special target screen 72 which contains fiber optic index strips. These strips are shown emerging from the target screen at 74 and 76 and exit 78 from the envelope of the CRT. To describe this feature in more detail, reference is made to FIG. 13 which is a sectional view through the conical, or intermediate, section 1313 of the CRT of FIG. 12. This sectional view shows optical fibers 82 positioned along the interior of envelope 80. The fibers can be round or rectangular, single strand or multi-filament. Two hundred fibers with outside dimensions of 10 mils apiece occupy but 2 inches of the circumference. In FIG. 14, four clusters of fibers designated 84 are shown to exit from the header 86 of a CRT. These clusters 84 may be considered to represent the exits such as 78 of FIG. 12.

In FIG. 15, a much enlarged portion of a multi-color target screen with fiber optic index strips is illustrated. This screen may be used as element 72 in FIG. 12. Rectangular light pipes 88 which preferably are made of glass are positioned between the blue and red strips arranged in a repeating sequence of red, green, and blue phosphors strips. The strips are all arranged parallel to each other and are placed in what is defined as a vertical alignment. It is comtemplated that a scanning electron beam will traverse these strips in a horizontal direction as at 90. This sweep action is typical of that employed in many types of index systems and so will not be described further, but it should be appreciated that other types of scanning actions are embraced within the full meaning of this invention. To simplify the description which follows, each color strip is designated to be 0.030 inch in width. The index strip 88 is set at 0.010 inch so that three color strips with an associated index strip take up 0.1 inch of horizontal dimension. Accordingly, for a target screen 20 inches wide there is room for 200 index strips and 200 triads of color strips. These figures represent a definition, or resolution, that is quite acceptable for commercial entertainment type television receivers. The trajectory 90 of the scanning electron beam crosses the target screen substantially at right angles to the vertical strips. Each time the beam strikes an index strip 88 an optical signal is generated therein which travels in both directions due to the light piping action within the index strip. The optical index signals emerge at the top and bottom of the target screen as at 92. The 200 glass strips are therefor joined or coupled together at the top and bottom to provide leadouts, again as at 92, for the optical index signal. Reference back to FIGS. 12-14 will show how these optical signals may be piped through the envelope of the CRT. To generate these optical signals, the index elements 88 carry dimples or recesses 94 which are drawn to a much larger scale in a crosssection taken through the line 17-17 of the target screen.

Thus, in FIG. 17, a substrate or glass faceplate 96 has deposited thereon the green, blue, and red phosphors together with the light pipe 88. The dimpled region 94 of the glass strip is coated with an electron-sensitive index phosphor 98 which suitably may be a P-lS or P-16 phosphor. A conventional electron transparent aluminum layer 100, or the like, is deposited over the phosphor strips. When the scanning electron beam strikes the index phosphor 98, the light generated as a consequence enters the fiber optic light pipe 88, becomes trapped therein, and is transmitted as the optical index signal.

Another configuration of a multi-color target screen is illustrated in FIG. 16 where indexing light pipes 89 are joined at the top of the screen to furnish a first optical index signal, and indexing light pipes 91 are joined at the bottom of the screen to furnish a second optical index signal. Naturally, this process of dividing the indexing light pipes may be continued until in the limit each light pipe (regardless of the phosphor associated therewith) can provide its own index signal. Also shown in this figure are non-light transmitting bars or rods or pins 93 which structurally tie the light pipes together for a purpose which becomes more evident from a discussion of the next figure in the drawing.

In FIG. 18, there is a cross sectional view of a target screen akin to the view shown in FIG. 17. The main difference is that the indexing light pipe 88 is placed on top of the phosphors rather than being placed directly on faceplate 96. With this type of construction the tie rods 93 can be used to advantage in that all the indexing light pipes can be pre-formed into a single subassembly which may be deposited on the target screen after all the color phosphors have been deposited.

Still another important arrangement of the target screens shown in FIGS. -18 is that which dispenses with the electron-sensitive phosphor 98. This can be done for the reason that electron-sensitive scintillating glasses are available which will yield an optical signal directly in response to electron bombardment. These glasses respond to impact by electrons moving under the accelerating voltages of the type normally employed in CRTs; and the scintillations decay fast enough so they can be used for indexing purposes even in high speed scanning systems. One example of such a scintillator is a cerium-activated high silica glass produced by the Coming Glass Company. The characteristics of this glass are described in detail in an article Glass Scintillators by R. .I. Ginther and J. H. Schulman in Volume NS-S, Number 3, Dec. 1958 of the IRE Transactions of the Professional Group on Nuclear Science. Particular reference is made to their FIG. 1 which shows that Ce-activated high silica glass excited by 10 Kilovolt electrons has a peak emission at approximately 4,000 Angstroms. Optical signals of this wavelength can be light piped and/or detected with relative ease. Reference is also made for details on glass scintillators to an article Neutron Detection with Glass Scintillators by L. M. Bollinger, G. E. Thomas, and R. J. Ginther appearing in Volume 17 (1962) No. l of Nuclear Instruments & Methods published by the North- Holland Publishing Company in Amsterdam; and to an article by A. L. Smith in the Transactions of the Electrochemical Society Vol. 96 (Nov. 1949) p.287-296.

Additionally, attention is drawn to the first of these three references where on page 95 the authors state:

One property of the cerium-activated glasses their ability to fluoresce at high temperatures.

It has been observed that the ultra-violet excited luminescence of cerium-activated high silica glass is not completely temperature quenched at even 800C.

It is also known that other glasses, and plastic and liquid phosphors scintillate in response to ultra-violet excitation. Hence, instead of using an electron beam to scan a target screen inside a CRT, it becomes possible via the foregoing target screen arrangements to use an ultra-violet beam to scan a large area screen, made up of elements responsive to ultra-violet excitation, for a large scale visual display; and to derive thereby all the advantages that go with beam indexing systems. This also applies when a scanning light beam, other than the ultra-violet, is employed.

In FIG. 19, a CRT with an envelope 102 has a target screen 104 which is shown in partial cross-section in FIG. 20. The target screen is also shown in a view from the left side in FIG. 21. This arrangement, of FIGS. 19-21, is presented to show that, in a more efficient manner than previously proposed, the envelope 102 of the CRT can serve as the light pipe transmission means for the optical index signals. The optical index signals are derived from the scintillator strips 108 which may take one of the forms already described. The strips 108 are in contact with the faceplate 106. They are to be impinged upon by the electron beam (furnished by electron gun 110) as are the phosphor layers 105 which are used to generate the visible display. The glass for faceplate 106 is chosen to have the same index of refraction (for the optical index signal) as the strips 108. It will then be found that the scintillations which originate in strips 108 will enter the faceplate; and they will be light piped toward the neck of the tube as shown by the arrows in the FIG. 19. The glass header of the CRT containing the pin connections 112 is sealed to the interior of the neck section 114 of the envelope so as not unduly to interfere with the transmission of the optical index signal as it proceeds to the transition light pipe member 116. Optical filter element 118 may be used to eliminate further transmission of undesired optical signals.

Inasmuch as glass scintillator materials now also come in powder or particle form the index strips 108 may also be made by imbedding these particles in the surface of the faceplate rather than by having them adhere thereto as just described. This may be done by fusing or sintering the particles to the faceplate. In this case, there is less need to match the indexes of refraction of the index strip to the faceplate and therefor a much wider range of glasses can be used. This arrangement also is symbolized by FIGS. 20 and 21. It should become clear from the foregoing that the index strips may be placed in the faceplate, or in the same plane as the phosphor layers of the target screen; or they may extend through the phosphor layers, or they may be covered over with the phosphor layers if the layers are thin enough to transmit at least part of the electron beam. Any of these conditions can prevail in target screens of the type under consideration.

Before concluding this description of my invention, a clear distinction should be noted with respect to the placement of the index generating optical fibers (or particles) in that they are positioned substantially parallel, or transverse, to the faceplate of the cathode ray tube and not perpendicular thereto. The perpendicular arrangement of optical fibers is known to be successful, to increase the brightness of CRT displays, and although a number of companies have produced tubes of this type none, to the best of my knowledge, have suggested or have provided the feature of this invention which places the fibers along the faceplate.

It should also be noted that the foregoing specification does not go into the details in chemistry which are necessary to construct a CRT of the type disclosed. These details have been omitted since they are not essential to understanding the instant invention. Suffice to say that optical fibers of diverse shapes, materials, and lengths can be manufactured; and that they can be adjoined to glass faceplates and vacuum sealed to CRT envelopes. Other considerations of a chemical nature such as relate to the fabrication or deposition of the target screens, processing temperatures for bakeout, fusing, sintering, etc. are also well known and likewise are omitted. Finally, circuit details have been omitted for the reason that these already are numerous circuit configurations which are well known to those skilled in the art of CRT display devices and which can make efficient use of the foregoing teachings.

Having thus described my invention and some of the uses to which it may be put, I claim:

1. In the combination of (1) an electron discharge device comprising an evacuated envelope containing an electron gun section for providing an electron beam, an intermediate section, and a target anode section arranged seriatum, with (2) light pipe scintillator means for picking up radiation which emanates from said target anode as a result of excitation by said electron beam and which transmits radiation representative of that picked up; the improvement characterized by the feature that said light pipe scintillator means is shaped in the form of a cylinder positioned adjacent to, concentric with, and inside the evacuated envelope in the region of said electron gun section.

2. An article in accordance with claim 1 in combination with a hollow light pipe cylinder mounted externally of the tube with one end thereof positioned in line with the internally disposed cylinder thereby to receive radiation transmitted through the envelope of the device from the internally disposed cylinder.

3. An article in accordance with claim 2 wherein the externally disposed hollow cylinder is divided into a plurality of longitudinal strips the terminal ends of which are brought together thereby to concentrate the radiation transmitted through the strips.

4. A cathode ray tube having an envelope with an electron gun section for providing a scannable electron beam and a target screen comprising electron-sensitive scintillating optical fibers disposed along, and not perpendicular to, the target screen on the side thereof which is to be impinged upon by the electron beam.

5. An article in accordance with claim 4 wherein the target screen and said optical fibers are mounted on the interior surface of the face plate of the tube envelope.

6. An article in accordance with claim 4 wherein the light pipes are an integral part of the substrate on which the target screen is mounted.

7. An article in accordance with claim 4 wherein the target screen is mounted on a substrate and the optical fibers are mounted on the target screen.

8. A cathode ray tube having an envelope with a gun section and an intermediate section, and a target screen section including optical fibers disposed along, and not perpendicular to, the target screen of the tube wherein the optical fibers are routed along the interior surface of the intermediate section of the tube envelope.

9. An electron discharge device comprising an electron gun for providing an electron beam, a target screen, and beam indexing means for locating the position of impact of the electron beam on the target screen, said index means comprising a plurality of elongated light pipes, positioned contiguous with said target screen on the side thereof impinged upon by the electron beam.

10. An article in accordance with claim 9 wherein the target screen comprises repeating groups of electronsensitive color emitting strips and the said light pipes are co-planar with the color emitting strips of the target screen.

11. A cathode ray tube with a plurality of optical fibers disposed inside the envelope of the tube and having a substantial lengthwise portion of the fibers positioned across the face plate thereof, the terminations of said fibers being routed through the neck section of the cathode ray tube.

12. A cathode ray tube of the beam-index variety comprising: (1) an evacuated envelope having a neck section including an electron gun for providing a scannable electron beam, 2) an intermediate section, and (3) a faceplate section associated with which is an electron-sensitive target screen for generating a viewable image in response to the scanning action of the electron beam; the intermediate section of the envelope connecting said neck section to said faceplate section; said target screen also being adapted to furnish index signals indicative of the position thereon of the scanning electron beam; in combination with (4) index-signal deriving means comprising a scintillator material which generates signals in the optical frequency range in response to excitation by the index signals, said scintillator having a surface thereof positioned adjacent to and coextensive with at least part of said intermediate section of the tube envelope.

13. The combination of claim 12 including light pipe means with entrance and exit regions positioned so that its entrance region is disposed adjacent the scintillator thereby to transmit optical signals derived from the scintillator material via a series of internal reflections to an exit region remote from the scintillator material where the optical signals are to be used for beamindexing purposes. n

14. The combination of claim 12 wherein the scintillator material is transmissive of the optical radiation it generates as a result of excitation by the index signals and is shaped into a light pipe with an entrance region thereof disposed proximate the intermediate section of the evacuated envelope, whereby scintillations generated in the interior of the light pipe-scintillator are transmitted via a series of internal reflections to an exit termination whereby they are to be used for indexing purposes. r v q 15. The combination of claim 14 wherein the exit termination is positioned near the neck section of the env a 16. The combination of claim 15 wherein the light pipe-scintillator is disposed on the exterior portion of the evacuated envelope and wherein the light pipescintillator has a speed of decay in the order of four nanoseconds.

17. The combination of Cantatas a; target screen comprises means for generating electromagnetic index signals in the ultraviolet region of the spectrum and wherein the light pipe-scintillator is responsive to index signals in the ultraviolet region of the spectrum.

18. A multi-color cathode ray tube of the beam-index variety comprising: an evacuated envelope having (1) a neck section including an electron gun positioned within the neck section to provide an electron beam for scanning a target screen, (2) a faceplate section having associated therewith an electron-sensitive target screen for generating a visible multi-color image in response to the scanning action of the electron beam, and (3) a frusto-conical-like intermediate section which connects the neck section with the faceplate section; the target screen having a pattern of periodically arranged phosphor strips for generating a visible image and a corresponding pattern of index strips which generate electromagnetic radiation in the range from ultra-violet to X-rays to provide index signal radiation for indicating the position of the electron beam on the target screen; and (4) scintillator means disposed adjacent the frusto-conical section and away from the immediate vicinity of the neck section, to convert electromagnetic energy derived from the index strips to electromagnetic energy of longer wavelength, and light pipe means to transmit the longer wavelength electromagnetic energy to an output remote from the target screen for indexing purposes.

19. The color cathode ray tube of claim 18 wherein the scintillator means is positioned on the inside of the tube adjacent the intermediate section thereof; including a thin metal filter, transmissive of said index signal radiation, positioned adjacent the said scintillator means on the side thereof facing the target screen.

20. The color cathode ray tube of claim 19 wherein the target screen comprises means for generating a plurality of different index signals, and wherein a plurality of scintillator means are provided to selectively detect each of the different index signals.

21. A cathode ray tube comprising: an evacuated envelope having l) a neck section including an electron gun positioned within the neck section to provide an electron beam for energizing a target screen, (2) a faceplate section having associated therewith an electron-sensitive target screen which generates electromagnetic radiation in response to excitation by the electron beam, and (3) a frusto-conical-like intermediate section which connects the neck section with the faceplate section; in combination with 4) scintillating material disposed adjacent to the conical-like section so as to be impinged upon by said electromagnetic radiation emitted by the target screen thereby to generate signals in the optical frequency range, and light pipe means, having the shape of said conical-like intermediate section and being positioned adjacent thereto, for picking up said optical signals and for transmitting them via a series of internal reflections into a concentrated form towards the neck section of the cathode ray tube.

22. The combination of claim 21 wherein the scintillator material is transmissive of its own radiation and is shaped to form said light pipe means, whereby scintillations generated in the interior of the light pipescintillator are transmitted in concentrated form towards the neck section of the cathode ray tube.

23. The combination of claim 22 wherein the target screen comprises means for generating ultraviolet radiation in response to electron excitation, and wherein the light pipe-scintillator is responsive to said radiation.

24. A cathode ray tube of the beam-index variety comprising: an evacuated envelope having l) a neck section including an electron gun positioned within the necksection to provide an electron beam-for scanning a target screen, (2) a faceplate section having associated therewith an electron-sensitive target screen responsive to the scanning action of the electron beam, and (3) an intermediate section which connects the neck section with the face-plate section; said target screen comprising means to furnish penetrating electromagnetic index signals indicative of the position thereon of the scanning electron beam; in combination with (4) index-signal deriving means, responsive to the indexsignals, comprising a light pipe-scintillator member capable of being penetrated by the index signals thereby to create scintillations in the interior region of the light pipe; said member being positioned adjacent to and co-extensive with said intermediate section and having the shape thereof whereby the scintillations generated in the light pipe-scintillator member accumulate in strength as they travel, via a series of internal reflections, towards an exit terminal where they are to be used for beam indexing purposes.

25. A beam-index color cathode ray tube in accordance with claim 24 wherein the target screen includes a plurality of different color producing phosphor strips arranged in a periodic and repeating sequence to furnish a direct view multi-color display in response to excitation by the scanning electron beam; and wherein the light pipe-scintillator is positioned on the outside of the tubeenvelope, and has a decay time constant not much greater than four nanoseconds.

26. A multi-color cathode ray tube of the beam-index variety comprising: an evacuated envelope having (1) a neck section including an electron gun positioned within the neck section to provide an electron beam for scanning a target screen, (2) a faceplate section having associated therewith an electron-sensitive target screen for generating a visible multi-color image in response to the scanning action of the electron beam, and (3) a frusto-conical-like intermediate section which connects the neck section with the faceplate section; the target screen having a pattern of periodically arranged phosphor strips for generating a visible image and a corresponding pattern of index strips which generate electromagnetic index signal radiation, outside the visible range, for indicating the position of the electron beam on the target screen; and (4) a light pipe member disposed adjacent the frusto-conical section with its entrance portion positioned away from the immediate vicinity of the neck section of the tube and facing the target screen, thereby to pick up and transmit the index radiation to an exit terminal of the light pipe via a series of internal reflections.

27. The combination of claim 26 wherein the light pipe member has the shape of the frusto-conical intermediate section of the tube envelope.

28. In combination: a beam-index color cathode ray tube having a target screen with means for generating ultraviolet index signals indicative of the position of the electron beam on the target screen; and means for detecting the index signals comprising a hollow conical light pipe-scintillator; the hollow cone being shaped in the form of a funnel and being positioned with respect to the target screen so as to be penetrated by the ultraviolet index signals thereby to produce scintillations in its interior region, said scintillations being in the optical frequency range and being transmitted through the light pipe-scintillator via a series of internal reflections, whereby the scintillations are accumulated within the hollow cone to emerge therefrom at its narrow end in concentrated form.

29. An article for detecting electromagnetic radiation which emanates from the target screen in a cathode ray tube in response to bombardment by the cathode rays comprising: a hollow conical light pipescintillator; the hollow cone being shaped in the form of a funnel and being positioned with respect to the target screen so as to be penetrated by the radiation to be detected thereby to produce scintillations in its interior region, said scintillations being in the optical frequency range and being transmitted though the light pipescintillator via a series of internal reflections, whereby the scintillations are accumulated within the hollow cone to emerge therefrom at its narrow end in concentrated form.

30. A cathode ray tube having an envelope with an electron gun section for providing a scannable electron beam and a target screen including optical fibers disposed along, and not perpendicular to, the target screen wherein a glass-like electron-sensitive scintillator material is adhered to the optical fibers on the side thereof which is to be impinged upon by the electron beam.

31. In a beam index apparatus comprising a scannable beam of energy, a target screen, and a control system responsive to the position of the beam on the target screen for controlling the excitation of the target screen, the improvement of the target screen comprising: a plurality of light pipe elements located substantially parallel to the target screen on the side thereof facing the scanning beam of energy, whereby optical index signals generated at the target screen as a result of excitation by the scanning beam are transmitted through the light pipes to exit terminals where they are used to synchronize the control system.

32. The improvement of claim 31 wherein the light v pipe elements are coated with a material sensitive to the scanning beam of energy for furnishing the optical index signals which are transmitted through the light pipe elements.

33. The improvement of claim 31 wherein the light pipe elements are sensitive to the scanning beam of energy thereby furnishing optical index signals in their interior region directly as a result of impact of the beam upon the light pipe elements.

34. The improvements of claim 33 wherein the beamsensitive light pipe elements generate optical index signals in response to excitation by a beam of radiation in the ultraviolet region of the spectrum.

35. A beam index multi-color display device comprising means for developing a scannable beam of energy; a target screen adapted to be impinged upon by the beam of energy; means for scanning the beam across the target screen; means associated with the target screen for generating optical index signals which indicate the position on the target screen of the beam of energy; means responsive to the optical index signals for controlling the beam of energy thereby to synchronize the energization of the target screen; including light pipe means positioned with respect to the target screen so that the optical index signals generated as a result of excitation at different regions of the target screen are transmitted through the light pipe means in a direction substantially parallel to the target screen to a peripheral region thereof, and including an electron gun for providing the scannable beam of energy in the form of an electron beam and an evacuated envelope having a gun section for housing the electron gun and a faceplate section for mounting the target screen, wherein the light pipe means comprises a plurality of elongated light pipes disposed on the interior side of the faceplate.

36. The device of claim 35 including phosphor material deposited on the elongated light pipes on the surfaces thereof that are impinged upon by the electron beam.

37. The device of claim 35 wherein the elongated light pipes are electron-sensitive thereby also generating optical index signals when excited by the electron beam.

38. The device of claim 37 including a plurality of different color emitting phosphors separated into repeating groups by the electron-sensitive elongated light pipes, means for bringing together the optical index signals transmitted through the light pipes to form a combined index signal, and means for transmitting the combined index signal through the envelope of the tube to an exterior region thereof.

39. The device of claim 35 including a plurality of different color emitting phosphors which are separated into repeating groups by the elongated light pipes.

40. The device of claim 39 wherein the exit terminals of the plurality of light pipes are brought together to form a common exit termination.

41. The device of claim 39 wherein the exit terminals of selected light pipes are brought together to form a first common exit termination, and the exit terminals of other selected light pipes are brought together to form a second common exit termination.

42. The device of claim 39 wherein the elongated light pipes are disposed substantially perpendicularly to the horizontal scanning direction of the electron beam and where the exit terminals of the light pipes are brought together to form a common exit termination.

43. The device of claim 39 wherein the transmission of index signals from a selected group of light pipes are merged to form a first index signal and the transmission of index signals from other selected light pipes are merged to form a second index signal.

Claims

10. An article in accordance with claim 9 wherein the target screen comprises repeating groups of electron-sensitive color emitting strips and the said light pipes are co-planar with the color emitting strips of the target screen.

12. A cathode ray tube of the beam-index variety comprising: (1) an evacuated envelope having a neck section including an electron gun for providing a scannable electron beam, (2) an intermediate section, and (3) a faceplate section associated with which is an electron-sensitive target screen for generating a viewable image in response to the scanning action of the electron beam; the intermediate section of the envelope connecting said neck section to said faceplate section; said target screen also being adapted to furnish index signals indicative of the position thereon of the scanning electron beam; in combination with (4) index-signal deriving means comprising a scintillator material which generates signals in the optical frequency range in response to excitation by the index signals, said scintillator having a surface thereof positioned adjacent to and co-extensive with at least part of said intermediate section of the tube envelope.

13. The combination of claim 12 including light pipe means with entrance and exit regions positioned so that its entrance region is disposed adjacent the scintillator thereby to transmit optical signals derived from the scintillator material via a series of internal reflections to an exit region remote from the scintillator material where the optical signals are to be used for beam-indexing purposes.

14. The combination of claim 12 wherein the scintillator material is transmissive of the optical radiation it generates as a result of excitation by the index signals and is shaped into a light pipe with an entrance region thereof disposed proximate the intermediate section of the evacuated envelope, whereby scintillations generated in the interior of the light pipe-scintillator are transmitted via a series of internal reflections to an exit termination whereby they are to be used for indexing purposes.

15. The combination of claim 14 wherein the exit termination is positioned near the neck section of the envelope.

16. The combination of claim 15 wherein the light pipe-scintillator is disposed on the exterior portion of the evacuated envelope and wherein the light pipe-Scintillator has a speed of decay in the order of four nanoseconds.

17. The combination of claim 16 wherein the target screen comprises means for generating electromagnetic index signals in the ultraviolet region of the spectrum and wherein the light pipe-scintillator is responsive to index signals in the ultraviolet region of the spectrum.

21. A cathode ray tube comprising: an evacuated envelope having (1) a neck section including an electron gun positioned within the neck section to provide an electron beam for energizing a target screen, (2) a faceplate section having associated therewith an electron-sensitive target screen which generates electromagnetic radiation in response to excitation by the electron beam, and (3) a frusto-conical-like intermediate section which connects the neck section with the faceplate section; in combination with (4) scintillating material disposed adjacent to the conical-like section so as to be impinged upon by said electromagnetic radiation emitted by the target screen thereby to generate signals in the optical frequency range, and (5) light pipe means, having the shape of said conical-like intermediate section and being positioned adjacent thereto, for picking up said optical signals and for transmitting them via a series of internal reflections into a concentrated form towards the neck section of the cathode ray tube.

22. The combination of claim 21 wherein the scintillator material is transmissive of its own radiation and is shaped to form said light pipe means, whereby scintillations generated in the interior of the light pipe-scintillator are transmitted in concentrated form towards the neck section of the cathode ray tube.

24. A cathode ray tube of the beam-index variety comprising: an evacuated envelope having (1) a neck section including an electron gun positioned within the neck section to provide an electron beam for scanning A target screen, (2) a faceplate section having associated therewith an electron-sensitive target screen responsive to the scanning action of the electron beam, and (3) an intermediate section which connects the neck section with the face-plate section; said target screen comprising means to furnish penetrating electromagnetic index signals indicative of the position thereon of the scanning electron beam; in combination with (4) index-signal deriving means, responsive to the index signals, comprising a light pipe-scintillator member capable of being penetrated by the index signals thereby to create scintillations in the interior region of the light pipe; said member being positioned adjacent to and co-extensive with said intermediate section and having the shape thereof whereby the scintillations generated in the light pipe-scintillator member accumulate in strength as they travel, via a series of internal reflections, towards an exit terminal where they are to be used for beam indexing purposes.

25. A beam-index color cathode ray tube in accordance with claim 24 wherein the target screen includes a plurality of different color producing phosphor strips arranged in a periodic and repeating sequence to furnish a direct view multi-color display in response to excitation by the scanning electron beam; and wherein the light pipe-scintillator is positioned on the outside of the tube envelope, and has a decay time constant not much greater than four nanoseconds.

29. An article for detecting electromagnetic radiation which emanates from the target screen in a cathode ray tube in response to bombardment by the cathode rays comprising: a hollow conical light pipe-scintillator; the hollow cone being shaped in the form of a funnel and being positioned with respect to the target screen so as to be penetrated by the radiation to be detected thereby to produce scintiLlations in its interior region, said scintillations being in the optical frequency range and being transmitted though the light pipe-scintillator via a series of internal reflections, whereby the scintillations are accumulated within the hollow cone to emerge therefrom at its narrow end in concentrated form.

32. The improvement of claim 31 wherein the light pipe elements are coated with a material sensitive to the scanning beam of energy for furnishing the optical index signals which are transmitted through the light pipe elements.

34. The improvements of claim 33 wherein the beam-sensitive light pipe elements generate optical index signals in response to excitation by a beam of radiation in the ultraviolet region of the spectrum.