FR2464553A1 - BICOLOR MEMORY TUBE FOR DISPLAY AND DIRECT INFORMATION VISION - Google Patents

Abstract

DIRECT VISION MEMORY TUBE INCLUDING A MEMORY TARGET, FOR STORING TWO-COLORED INFORMATION AND DIRECT READING OF INFORMATION IN ANOTHER COLOR. THE TUBE CONSISTS OF A TARGET 16 IN THE FORM OF MIXED PARTICLES WITH PHOSPHORES, CARRIED BY A CONDUCTIVE SUPPORT 60; PART OF THE PARTICLES CONSISTS OF LOW SURFACE PHOSPHORUS 66 FORMING HIGHLIGHTS 62 ON THE SUPPORT; ANOTHER PART 64 CONSISTS OF PHOSPHORUS CAPABLE OF STORING CHARGE IMAGES; THESE PHOSPHORES WORK AS ELECTRODES UNDER DIFFERENT VOLTAGE LEVELS TO SIMULTANEOUSLY DISPLAY STORED AND PASSING INFORMATION IN THREE DIFFERENT COLORS. APPLICATION TO LUMINESCENT DISPLAY OF STORED AND PASSING INFORMATION.

Description

we already know the direct display in color, which consists of mixing

  between them, in an adequate ratio, two luminescent spectra

  different to form a phosphorus target that becomes lumines-

  in at least two distinct colors. One of the phosphor particles

  phore is a phosphor phosphor with low voltage memory, while the other phosphor particle does not become luminescent under low voltages but is an effective emitter of a different color under

  higher voltages, so that

  formations not memorized or direct in a color other than that of the stored or memorized information. This type of memory target can

  Best achieved by complying with the principles of the application for

  US Patent No. 802,615 filed June 2, 1977.

  It is also possible to mix with the phosphorus target other

  phosphorus particles having a third color, in order to achieve a

  memory tube for two-color display passing from direct vision type.

  The main disadvantage-that such a target presents would be the small quantity of phosphorus particles, luminescent under low voltage,

  which would be distributed over the entire target, and the fact that

  memorized training would be rather blurry, so hard to discern.

  The present invention relates to memory tubes having

  thodiques, and more particularly to a direct vision bistable memory tube which directly displays bicoloured passing information which

  differ from the color of the information stored in memory.

  The present invention consists in providing a target of

  cathode ray tube, of the direct vision type, comprising a dielectric storage layer based on mixed phosphors. This

  mixed material comprises two phosphors with different characteristics

  their color emission capacity; one is a phos-

  phore that becomes luminescent under low voltage, while the other is

  a phosphor that emits light of a different color under a

  higher, and preferably clearly distinct,

  the one that makes the first low-voltage phosphor luminescent. A system

  collector electrodes passes through the dielectric memory layer.

  in order to collect secondary electrons emitted by the image of

  recorded by the nhosmhore with memory, and these electrodes collec-

  are made from a conductive but non-encrusted phosphorus

  the color of which differs from that of the phosphors constituting

the mixed dielectric layer.

  One of the mixed phosphors has a neutral layer which eliminates

  the luminescence at low voltage and can raise the operating level of the target and thereby increase the luminescence of the stored information. The collecting phosphors also comprise

  a neutral layer and they are conductive, which allows them to collect

  read secondary electrons but forbid their luminescence, unless they

  are excited by electrons under a higher voltage: at this point

  so much, they become luminescent with a color other than that of

mixed phosphors.

  One of the first aims of the invention is to provide a bistable type of memory tube with direct vision in which the information

  Passive or non-memorized is two-color.

  Another object of the invention is to provide a memory target

  bistable type, intended to be used together with a bis-tube

  a direct-view table that displays passing or non-passing information

  stored or direct in two colors, and the recorded information

  in a color other than that of the above-mentioned passing information.

  Another object of the present invention is to provide a bistable memory target capable of displaying information stored with

  higher luminescence while simultaneously displaying information

  not recorded in two different colors, other than

saved information.

  A further object of the present invention is to provide

  a bistable memory target which contains a collective electrode system

  produced from conductive phosphorus particles, each

  Phosphorus particle being coated with a neutral layer.

  In addition, the object of the invention is to provide a bistable type memory target which comprises a mixture of two types of

  different phosphors, which emit different colors and

  kill the phosphor layer with memory; one of the types of phosphor particles being memory and dielectric, and intended for the emission of light to its own color, while the other type of phosphor particles has a coating or neutral layer around each particle in order to to ensure the inhibition of the luminescence under low voltage and to increase the operating level of the target, and thus make it possible to display the recorded or memorized information with greater luminescence. Finally, the purpose of the invention is also to provide a bistable memory target that can be used to display information

  intermediate polychromics together with stored information.

  Other purposes, features and advantages of this

  will come out during the reading of the detailed description

  which follows, if reference is made at the same time to the figures of the accompanying drawings, in which: FIG. 1 schematically shows a memory tube of the cathode ray type and direct vision, made according to the invention, and the circuits FIG. 2 shows on an enlarged scale and in partial cross-section, taken along line 2-2 of FIG. 1, a preferred embodiment of FIG.

  embodiment of a memory target according to the present invention.

  If we first refer to Figure 1, we see that a

  be bistable to memory and to direct vision 10 includes an envelope

  cup 12, provided with a plate or transparent front end face

  14. This plate or front face 14 supports a memory target 16 com-

  taking a conductive target electrode 18 and a memory dielectric layer 20. In the opposite or rear end of this tube is mounted a writing or recording gun 22 comprising a cathode 24, a control gate 26 and a structure Anodic focusing and accelerating beam 28 for forming an electron beam which travels at high speed towards the target 16. The beam 30 is deflected by signals applied to the deflection plates

  32 and vertical deflection plates 34 by means of cir-

  Conventional bakeware 36. The memory tube 10 is provided with

  in addition to one or more auxiliary guns 38 for bombarding uni-

  formally the memory dielectric layer with electrons at relatively slow speed. The cathodes of the auxiliary guns are connected

  to a suitable ground potential source, at low voltage (0 volts).

  Several electrodes are arranged on the inner surface of

  the envelope 12 between the auxiliary guns 38 and the target 16. These

  The electrodes are preferably in the form of spaced coatings or strips of conductive material such as silver, graphite, or the like. A first electrode 40 in the form of a strip covering the wall of the tube serves essentially as a focusing electrode for the auxiliary electrons emitted by the guns 38. It is connected to a

  appropriate source of positive voltage, for example about +250 volts.

  A second electrode 42 formed by a band covering the wall of the tube

  and spaced from the electrode 40 while being connected to a voltage less

  sitive, for example about + 150 volts, serves as a focusing electrode.

  tion and alignment or collimation. A third electrode 44,

  in the form of a band adhering to the wall of the tube, is spaced

  relative to the electrode 42 and connected to an even less positive voltage

  for example of about + 125 volts, and also serves as a focusing electrode and collimation. A fourth electrode 46, formed by a band which adheres to the wall of the tube, is placed between the electrode 44

  and the memory target 16, while being spaced from these elements.

  This electrode 46 is connected to a still less positive voltage (about + 75 volts) and functions as a focusing and collimation electrodiode, although it can also serve as an auxiliary collector for secondary electrons emitted by the peripheral portion of the electrode. the memory target. As a result of the collimating effect produced by the electrodes formed by the strips adhering to the walls, the electrons emitted

  Auxiliary guns are distributed in a virtually uni-

  form over the entire surface of the target 16.

  It should be emphasized that a conventional resistive coating 48, for example of the type known under the tradename "Aquadag", is provided on the inside of the funnel-shaped portion of the casing 12, and that

  this coating is electrically connected to an insulating shield (not re-

  presented) provided in the writing gun 22. This coating 48 thus serves

  extending the second anode of the writing gun (not shown).

  The voltages applied to the electrodes formed by the strips adhering to the walls and which are shown in the reference numerals 40, 42, 44 and 46,

  are properly adjusted to ensure a focus and

  optimal delivery of the electrons coming out of the auxiliary guns, and the particular values cited here and indicated in the drawing are not well

  heard data only as an example.

  The target electrode 18 is conveniently connected to the midpoint of a voltage divider composed of resistors 50 and 52. The resistor 50 is set to apply a potential of about + 200 to

+ 300 volts at the target electrode.

  The cathode of the writing gun 22 is connected to a potential of strongly negative DC current, preferably around -6,000 volts, through the moving contact of a switch 23. The control gate 26 is connected to the moving contact a bipolar switch with two directions

  53. In the MEMORY position of the switch 53 and the -6KV position of the

  mutator 23, the gate 26 is connected to a direct current potential VG 1 in order to produce a suitable reverse bias polarization of the cathode gate, which determines the bombardment of the target 16 by the write beam 30 formed by great speed. When struck by this writing beam, the dielectric coating 20 emits secondary electrons which are then collected by the electrode 18. The storage area of the layer 20 is excited positively by the secondary emission, and maintained at a relatively positive potential after the beam 30 has encountered the low power electrons emitted by the auxiliary guns 38. With this well-known method, it is formed

  a charge image stored or recorded on the dielectric layer.

  When the switch 53 is placed in its position W.T. or write pass or direct, the control gate is connected to the output of a generator 54 of rectangular pulses, which applies pulses 56 of positive pace to said grid. These pulses 56 have a maximum voltage level equal to -VG I, and a minimum (more negative) voltage level sufficient to de-energize the write gun. Cutting of the writing beam, during a part of the time intended for it to bombard a given area of the target, allows, thanks to the auxiliary electrons, to discharge the charge image formed in the coating

  dielectric recording. This avoids memorization or recording

  very much of the passing image. A more detailed description of the function

  such a pulsed pass-through writing system is the subject of

  from US Patent No. 3,430,093 issued to Winningstad.

  Referring now to FIG. 2, the memory target incorporated in the memory tube 10 is seen in cross-section and with a high magnification. This target 16 comprises a transparent support, in the form of a facade plate. or anterior 14, coated with a thin conductive film 60 of tin oxide. A multitude of protruding "points" 62 of the conductive material, based on surface-weakened phosphor, are distributed in a regular pattern over the entire exposed surface of the film 60. Preferably, this phosphor-based conductive material

  consists of blue P-22 (ZnS: Ag) coated with a sulphate precipitate

  cobalt particles which are diffused in the phosphorus particles by a heat treatment, for example according to the process taught in US Pat. Nos. 3,664,862, 3,767,459 and 3,826,679. The highlights 62, which will advantageously be a substantially cylindrical or conical shape, are electrically connected to the tin oxide film. Thus, the conductive film 60 and the phosphor points 62 together form a collector or target electrode 18. On the conductive film 60 and around the points 62 is deposited a dielectric storage layer 20,

  which has at least one character of semi-continuity. Points 62

  pour this layer 20 and their protruding end is exposed and re-

  thus picks up secondary electrons emitted by adjacent charge images, whose charge is positive. Due to the presence of the neutral or dead layer surrounding each of the phosphor particles forming the salient points 62, these do not become luminescent, except for a voltage of -8KV or more, depending on the thickness of said phosphor particles.

neutral or dead layer.

  According to the present invention, the layer 20 is composed of a mixture of particles of different phosphors, which comprise particles 64 of a phosphor capable of storing charge images, and particles of a different phosphorus 66. The latter is a phosphorus whose surface is weakened, and one chooses

  so that it emits in a different color, preferably

  significantly different from that of phosphorus 64 when it is

  bombarded by electrons coming out of the low power auxiliary gun

  this. Due to the presence of weakened surface phosphor particles 66 in the layer 20, an increase in the operating level of the memory target occurs, which increases the luminescence of

  stored information. Phosphors capable of satisfying these conditions

  -30 tions include the red emission phosphors P-22R, such as -

  Y 2 O 2 S: Eu, Y 2 O 3: Eu, Gd 2 O 2 S: Eu, Gd 203 - Eu and YVO 4: Eu. The red phosphorus particles 66 are weakened on the surface to provide a neutral layer having the desired thickness. A method to obtain the

  desired neutral or dead layer around each of the phosphor particles

  The red phosphorus of the oxysulphides (Gd 202S: Eu and Y2 02S: Eu) consists of cooking the target with air at a temperature of between 450 and 5500C. To this effect, reference should be made to J. W. Haynes and J. J. Brown, "Preparation and Luminance of Selected Eu-activated rare earth-oxygen-sulfur-compounds", Journal Electrochem. Society, Col. 115, p. 1060 (1969). This allows for a neutral layer of oxysulphate whose thickness is a function of the cooking time at the indicated temperature. Another method of forming a neutral or dead layer on the surface of each red phosphorus particle for each of the rare earth oxides or oxysulfides mentioned above is to form a paste with the red phosphorus particles in an acidic solution. and at a controlled temperature between room temperature and

  800C, and also to a controlled concentration of phosphorus in the solu-

  in such a way that the pH thereof is less than 4.5. This is

  produced a superficial reaction to produce a dead layer of phosphate

  of rare earth whose thickness depends on the aforementioned variables. It is

  has just referred to U.S. Patent Nos. 3,607,371 and 3,927,240

  as regards the coating of phosphors with phosphates.

  Phosphorus 64 is advantageously a recording phosphorus,

  green luminescence emitter, such as P-I (Zn SiO: Mn).

2 4

  Both types of phosphorus particles are intimately

  dried, or in the form of sludge, and deposited on the film

  conductor 60 of the target electrode 18 according to any known method, for example

  by adopting the method set forth in U.S. Patent No. 3,956,662 issued to McTeague et al. The relationship between the two types of

  The phosphors that form the mixture may vary between about 10% and

  80% by weight of phosphorus 64, the remainder being phosphorus 66.

  A preferred composition comprises about 24% by weight of phosphorus P-1, about 56% of red phosphorus for neutral or dead layer (or a mixture

  phosphorus P-22R) of the rare earth type mentioned above, with envi-

  20%. of P-22 blue, as collecting electrodes 62. A target

  memory device provided with a dielectric layer according to this composition

  will produce a green display of stored charge images and an

  orange and blue image of direct charge images. The mixed layer

  holds about 33%. by weight of phosphorus P-1 and about 67% by weight of

phosphorus P-22R.

  According to a mode of operation by writing or di-

  rect, we connect the switch 23 to the terminal -6KV while maintaining the

  switch 53 in its position W.T. This results in a

  stored information, provided of course that such information has been stored, while the information

  or direct is displayed in orange, which is a combination of

its red and green phosphors.

  In another mode of operation by passing information, the switch 23 is connected to the -8KV terminal, while the switch remains in its WT position. If the stored information is displayed in green color, the passing information will be displayed in FIG. blue due to the emission made from phosphores 66, 64, plus points

  62, which differs not only from the passing information obtained during

  that the switch 23 is placed on its position -6KV, but also the

memorized training.

  According to another possible mode of operation by passing information, the switch 23 is placed between the positions -6KV and -8KV, while the switch 53 is maintained on its position WT If the stored information is displayed in its green color, the Direct or Passive Information will be displayed in the orange and blue colors, which differ from those of the stored information. The voltages of the writing guns may be less than -6KV or greater than -8KV, depending on

the design of the instrument.

  Naturally, the tube can work either in the only way

  "memory" or "storage", either according to one or both modes of informa-

  direct or passing color, at will. Thus, the cathode ray tube can function as an intermediate full color pilot,

with bistable storage.

  It is understood that the color coding of the direct or passing information is not limited to its application to the

  memory tube target structure given here by way of example.

  Other suitable target structures are described in US Pat. Nos. 3,293,474 issued to Gibson, Jr .; 3,401,293 issued to Morris; 3,531,675 issued to Frankland, and

3,614,820 issued to Morris.

  About 20% of each of the collecting electrode elements 62 can be made of metal powder instead of 100% phosphorus, in order to obtain an adequate operating range of the cathode ray tube, since my resistance of the collectors in the form of Phosphorus highlights may be too high, which decreases the efficiency of secondary electron reception and reduces the operating range of the cathode ray tube. We can possibly

  about 28% of the collector elements 62 of the electrode to be

  shot of metal powder, while the rest can be constituted by

  conductive phosphorus. As an alternative, the point system

  lants can be made in the form of a mixture of phosphors 64 and 66 coated with a conductive phosphor layer.

  Brighter information can be displayed by

  parence, thanks to the next target-the invention, if the collectors 62 also emit light at passing information voltages that are above -8KV. Similarly, by weakening the surface of the red phosphorus particles by means of a phosphate layer, the operating level of the memory target is increased, which increases the luminescence of the green phosphorus particles which results from their mixing. with red phosphorus particles to form the layer of

  phosphorus. The weakened surfaces of the electrode electrodes

  these in conductive phosphorus will collect secondary electrons during

  in operation with storage or storage, without producing luminescence, unless exceeding a threshold voltage level. One can possibly use a double barrel structure

  electrons to replace the switched voltage sources that supply

  lie a single cathode, if any.

  From the foregoing, it is obvious to any one skilled in the art that various changes can be made to the preferred embodiment of the invention described and shown without departing from

basic principles of it.

Claims (16)

  1. Memory tube, cathode ray tube and direct vision,   essentially taking the following elements: a) an evacuated envelope (12) whose front end face (14) is transparent to light; b) a memory target (16) comprising a dielectric memory layer (20) of phosphor material mounted within said envelope; c) means (22) for bombarding said high speed electron beam memory dielectric layer to form a charge image; and d) means (38) for bombarding said memory dielectric layer with electrons at a high speed. relatively slow speed, in order to produce the bistable storage of charge images with at least one potential   equal to the minimum critical voltage required to ensure this   authorization; e) means for presenting charge images whose   potential is less than said minimum critical voltage.   said tube being characterized in that said phosphorus-based material comprises a substantially uniform mixture of a first phosphor (64) capable of providing bistable storage of the images of   charge and a second phosphorus (66) weakened on the surface and whose   the color function differs from that of the first phosphor, the second phosphor having an output luminescence yield which, as a result of the bombardment by said slow-moving electrons, is less than the yield of said first phosphor, so that the bombardment of the mixed material by said high-speed electrons translates into   the emission of a luminous image perceived with a certain color, tan-   say that the bombardment of said material by said slow-moving electrons results in the emission of a luminous image which corresponds to   a stored charge image of a noticeably different color   rent, phosphorus weakened on the surface making the tube work a higher level of tension.   2. Memory tube according to Claim 1, characterized in that   said phosphorus target (16) consists of a mixture of phosphorus P-1   and phosphorus P-22R weakened on the surface.   3. A memory tube according to Claim 2, characterized in that said phosphorus P-22R is selected from the group consisting of: Y 202 S: Eu, Y203: Eu, YVO4: Eu, Gd 202S: Eu, Gd203: Eu, and mixtures of these substances. A memory tube according to Claim 2, characterized in that said mixture of the memory target contains about 33% by weight of phosphorus P-1, the balance being composed of about 67% phosphorus P-22R weakened on the surface.   5. A memory and direct vision target for a cathode ray tube, of the type comprising a light-transparent support, made of electrically insulating material, as well as means (20) fixed to this support for constituting a collecting electrode, characterized in that   it comprises a dielectric layer of phosphor-based material   phore on one side of said support, this material comprising a mixture   substantially uniformity of phosphorus particles, including particles   of a first phosphorus (64) capable of ensuring   a charge image table and particles of a second phosphor (66) with a weakened surface, capable of emitting light whose color differs from that of the first phosphor when they are bombarded by high-speed electrons from a a cathode ray tube writing gun (22) having a lower luminescence efficiency than the first phosphor in response to slow velocity electron bombardment by an auxiliary gun (38)   cathode ray tube, the phosphor (66) weakened by   face having the effect of making said target work at a level higher voltage.   Target according to Claim 5, characterized in that the first phosphorus (64) is a phosphorus P-1 while the second phosphorus   (66) weakened surface is a phosphorus P-22R.   Target according to Claim 6, characterized in that the   said phosphorus mixture forming said memory target (20) contains about 33%, by weight of said phosphorus P-1 (64) the remainder, about 67%,   being constituted by said phosphorus P-22R (66) weakened on the surface.   Target according to claim 7, characterized in that said   surface-weakened P-22R phosphorus (66) is selected from the   taking: Y202S: Eu, Y203: E1, YV4: SEu, Gd 203: Eu, and mixtures of these substances.   9. Cathode ray and direct vision memory tube, of the type comprising:   a vacuum evacuated envelope (12) provided with an anterior face   re terminal transparent to light (14);   b) a memory target (16) mounted within this housing   loppe and comprising conductive means (60) provided with a system of collecting electrodes (62, 64, 66) electrically connected to said conductive means and a dielectric memory layer (20) of phosphor material which covers said conductive means , while   the collecting electrodes pass through this dielectric memory layer   that the opposite ends (62) of these collecting electrodes are exposed; c) means (22) for bombarding said memory target with a high-speed electron beam to form a charge image thereon; d) other means (38) for bombarding said memory layer   dielectric with slow-moving electrons to produce the   Bistable image reproduction. load having a potential at least equal to a minimum critical voltage necessary to ensure this storage; e) means (38) for presenting charge images whose potential is less than said minimum critical voltage, which tube is further characterized in that said dielectric memory layer (20) comprises a substantially uniform mixture of a first phosphor (64) capable of providing bistable storage of charge images and a second phosphor (66) weakened on the surface and whose emission color differs from that of said first phosphor, the light output of said phosphor second phosphorus, as a result of the bombardment carried out with said electrons at high speed,   being lower than that of said first phosphorus, this bombardment of   mixed material by said high-speed electrons determining the emission   image of a certain perceived color, while the   bombardment of said material by said slow-moving electrons is   by issuing a luminous image that corresponds to an image of 246o45 53-   stored charge whose color is noticeably different from said perceived color, said weakened phosphor (66) having the effect of   to operate the tube at a higher voltage level.   A memory tube according to Claim 9, characterized in that said collecting electrodes comprise a phosphor-based conductive material whose color emission differs from that of said first and second phosphors when they are bombarded by said beam. high-speed electrons.   11. Memory tube according to Claim 10, characterized in that the phosphor-based conductive material comprises particles of phosphorus with weakened surface.   A memory tube as claimed in Claim 11, characterized in that said dielectric memory layer (20) comprises a mixture of phosphorus P-1 and phosphor P-22R with a weakened surface, and said phosphor-based conductive material comprises phosphorus P-22B to weakened surface.   A memory tube according to Claim 12, characterized in that said weakened phosphor P-22R is selected from the group consisting of: Y 0 S: Eu, Y 0: Eu, YV 2: Eu, GdO 3: Eu, Gd 2 O 2: Eu, or 22 2 2 3, V4: u, 3d2: 2 mixtures of these substances.   A memory tube according to Claim 12, characterized in that said conductive phosphor-based material with a weakened surface includes ZnS: Ag coated with CoS.   A memory tube according to Claim 12, characterized in that said memory target contains about 24% by weight of phosphorus P-1, about 56% by weight of P-22R phosphorus with a weakened surface, the   remaining phosphorus P-22B weakened surface.   16. A memory and direct vision target, for use with a cathode-type cable, of the type comprising: a) a light-transparent element (14), made of electrically insulating material;   b) a conductive layer (60) applied to one side of this element   characterized in that said conductive layer is covered with a phosphor material (16), a first phosphor being in contact with said conductive layer while a second phosphor is electrically connected to said conductive layer, the first phosphor   comprising a mixture of two phosphorus particles, one of the   cules of this mixture being a low voltage memory phosphor while the other particle of this phosphor mixture is luminescent under a higher voltage and gives a color different from that of said first memory phosphor, the second phosphor forming a system   collecting electrodes for collecting secondary electrons   daries emitted by charge images of said first phosphor with memory   and being luminescent at a voltage higher than that of other   phosphorus particles and with a color other than those of the first   phosphorus with memory and other phosphorus particles.