EP0075512B1 - Tube intensificateur d'images à mémoire, et mode de mise en oeuvre - Google Patents

Tube intensificateur d'images à mémoire, et mode de mise en oeuvre Download PDF

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Publication number
EP0075512B1
EP0075512B1 EP82401670A EP82401670A EP0075512B1 EP 0075512 B1 EP0075512 B1 EP 0075512B1 EP 82401670 A EP82401670 A EP 82401670A EP 82401670 A EP82401670 A EP 82401670A EP 0075512 B1 EP0075512 B1 EP 0075512B1
Authority
EP
European Patent Office
Prior art keywords
voltage
image
cell
application
screen
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP82401670A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0075512A1 (fr
Inventor
Jean-Claude Boit
Jean-Pierre Galves
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thales SA
Original Assignee
Thomson CSF SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0075512A1 publication Critical patent/EP0075512A1/fr
Application granted granted Critical
Publication of EP0075512B1 publication Critical patent/EP0075512B1/fr
Expired legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/18—Luminescent screens
    • H01J29/182—Luminescent screens acting upon the lighting-up of the luminescent material other than by the composition of the luminescent material, e.g. by infra red or UV radiation, heating or electric fields
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/50—Image-conversion or image-amplification tubes, i.e. having optical, X-ray, or analogous input, and optical output
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2231/00—Cathode ray tubes or electron beam tubes
    • H01J2231/50—Imaging and conversion tubes
    • H01J2231/50005—Imaging and conversion tubes characterised by form of illumination
    • H01J2231/5001—Photons
    • H01J2231/50031—High energy photons
    • H01J2231/50036—X-rays
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2231/00—Cathode ray tubes or electron beam tubes
    • H01J2231/50—Imaging and conversion tubes
    • H01J2231/50057—Imaging and conversion tubes characterised by form of output stage
    • H01J2231/50063—Optical

Definitions

  • the invention relates to an image intensifier tube and its implementation.
  • the function of such a tube is to produce a bright image with high brightness.
  • the image is formed on the exit screen of the tube, the screen of which is exposed to incident radiation.
  • a stream of electrons, emitted by a photocathode incorporated in the input screen ensures the transfer of the signal from each point from one end to the other of the tube.
  • the output screen is a simple cathode-luminescent screen, capable of emitting light under the effect of bombardment by electrons, namely those of the flux in question. They then only allow operation in real time, where the image is visible on the output screen only when it is produced on the input screen, with the persistence near the traces on the 'output screen, of variable duration according to the provisions adopted, but, in any case, very limited in the current state of the art of these screens.
  • This kind of screen is also sensitive to the action of electronic bombardment, like the cathode-luminescent screens to which reference was made first, but in a completely different respect: electronic bombardment adds its action here to that of applied voltage and is equivalent to an additional voltage which would be superimposed on it. In particular, it would make it possible to cross the threshold voltage for an applied voltage lower than the value of this threshold and, in general, various signal processing operations, all of which will be more fully specified below.
  • CTR cathode ray tubes
  • this interest had to be even greater for tubes no longer of the TRC type, but in which, unlike the case of these tubes, the image on the output screen is formed by a flow of electrons whose l 'impact covers at once the entire surface of the exit screen, which is, so to speak, at a given moment, "sprinkled" entirely by the beam.
  • This watering can also be permanent during the shooting, or applied by pulses, as we will see later.
  • This case is typically that of radiological image intensifiers (IIR), intended for the medical uses mentioned above, and bright image intensifiers (IIL) reserved, in other fields, for the collection of images with low illumination or nocturnal.
  • IIR radiological image intensifiers
  • IIL bright image intensifiers
  • tubes of the same type of the prior art under the conditions which will be exposed. It concerns, in a generic way, all the tubes in which, as we said, the output screen is covered at all times at all its points by the flow of electrons carrying the signal coming from the input of the tube.
  • Figure 1 shows in section an example of an electroluminescent screen structure.
  • dielectric material for example aluminum oxide, tantalum oxide, silicon nitride, etc.
  • layers 3 and 5 of dielectric material for example aluminum oxide, tantalum oxide, silicon nitride, etc.
  • These three layers have approximately equal thicknesses of the order of a few hundred nm; they are taken between two conductive layers 2, 6; layer 2, made of indium tin oxide, is transparent to light radiation emitted by the cell; layer 6 made of aluminum is opaque to these radiations, to avoid any disturbance of the photocathode. In the tube, layer 6 faces the electron bombardment.
  • this difference in potential is generally alternative and of any shape: sinusoidal, with pulses of various shapes, rectangular, triangular ..., of varied width and frequency.
  • the whole rests, by the layer 2, on a thick glass support 1, which is not shown in proportions as to its thickness.
  • This type of screen has the property of emitting light radiation in the visible spectrum when it is excited by the applied voltage. This emission begins only above a certain threshold voltage V s and increases rapidly in intensity beyond this value. To fix the ideas, it will be indicated that a current value of V s is approximately 150 volts, the point of use, corresponding to the tention Vu, generally not exceeding 180 volts (Vu-V s of the order of 30 volts ), under normal operating conditions: point at the extreme top of the curve in Figure 2 described below.
  • the frequency of this very variable voltage is for example 5 kHz, all these figures being given by way of example and depending on the exact composition of the screen, in particular that of layer 4.
  • the same type of screen may have a memory effect linked to the hysteresis phenomena of which it is the seat (see Howard - Appl. Phys. Letters vol 31 page 399 September 1977).
  • the screen, or electroluminescent cell is excited by the positive and negative pulses of a voltage of amplitude V e called maintenance voltage.
  • the cell is not illuminated.
  • the cell is then energized with an addressing voltage Va (always in + and - pulses).
  • Va an addressing voltage
  • V e pulses V e to it .
  • the operating point is located at B.
  • the luminance is LB.
  • the cell emits light, whereas in the first case for the same voltage, no light was emitted (V e less than V s ).
  • V ef is the erasing voltage
  • V e (maintenance voltage).
  • the cell emits no light.
  • an input screen generally by the reference 21, located at the left end of the envelope and, at the other end, an output screen 22 towards which converge (arrows) the electrons emitted by the photocathode incorporated in the screen 21, in which it is placed opposite another part of the screen, possibly in contact with it and called a scintillator, which converts the incident radiation, X-rays in the example, in photons for the use of the photocathode.
  • a series of electrodes designated overall by the reference 23, each represented with its passage, without reference, ensures the acceleration and the concentration of the electrons towards the exit screen of small size, compared to the entry screen; the output screen in question is represented, as is often the case, arranged at the bottom of an equipotential box without mark, the front face of which is pierced with a small hole at the point of the point of convergence of the electron beam.
  • the object whose image we want to form, exposed to incident radiation (arrows on the left) has the mark 25.
  • FIG 4 gives some of the possible uses of an intensifier tube according to Figure 3, which will be discussed below.
  • the light beam 12 is taken up either by a photographic camera 26 for the presentation of films, or by a photographic camera 24 for the production of separate photos (radiophotos), or by a television camera 28, for viewing in real time, on a television monitor 30.
  • a photon gain of 150,000 is commonly obtained with an image intensifier, namely 150,000 light photons emitted by the output screen for 1 incident X photon.
  • This density is spatially modulated by the object whose image is sought to reproduce, because the intensity of the X-rays having passed through the object is a function of the point crossed.
  • the electron beam bombardment induces at each point of the light-emitting cell an internal polarization, the field of which is added to the field created by the alternating voltage applied to the cell; this is equivalent to an increase in the voltage V applied to the cell.
  • the device operates in pulses: the X-ray is applied to the object in pulses.
  • the cell is addressed by the beam, spatially modulated, as we have said; it receives at its various points the image signal, that is to say the information; this information is only perceived on the condition that the voltage applied to the cell is sufficient so that, superimposed on the addressing signal, it is greater than the threshold voltage V s .
  • V an applied voltage
  • This is also possible, by applying a constant voltage V equal to V e ; the difference between the two cases being that in the first image is visible during addressing and that in the second it is not.
  • Reading of the information can then be done in real time during the whole time of addressing, part to the left of the line in the figure; it can be extended, immediately after the X pulse, for the entire desired time, maintaining the maintenance voltage V e between the faces of the cell, part to the right of the line: it can also be stopped for the desired time and restored again; during this stop there is storage, that is to say memory of the information.
  • Figure 6 shows the voltage diagram corresponding to the latter case.
  • This interruption can be obtained, as shown in this figure, by giving the applied voltage a value invariable in time but sufficient to prevent erasure, greater than V ef .
  • This voltage is advantageously the previous voltage V e .
  • the cell under constant tension, gives no image, this being stored extinct; this reappears at the end of this step, when the alternating voltage V e is again applied to the cell, and remains for the entire time r 2 that this voltage V e is maintained.
  • the operation can be repeated several times, several successive readings of the same image being possible, separated by time intervals where it is stored.
  • Another important point, and which constitutes another advantage of the invention, is that the gain in photons, ratio of the number of light photons emitted by a point of the cell to the number of X photons received by the corresponding point of the input screen, can reach extremely high values, much higher than that cited, thanks to the possibility of storage and successive observations for a very long total time; this is of great interest for the production of radiophotos (24, FIG. 4); conversely, with a given gain, it is possible to reduce the radiation dose.
  • This gain depends moreover, all other things being equal, on the frequency of the alternating voltage applied; it is multiplied by a factor of around 100 when going from 50 Hz to 50 kHz.
  • the tubes of the invention can be easily adapted to the optimal value corresponding to each of the uses which is made of the image produced on the tube output screen (see FIG. 4), with incident irradiation intensity. fixed.
  • the thin film structure of the electroluminescent cell allows high resolutions of the output images.
  • the cells on their support commonly have the form of discs from 25 to 50 mm in diameter.
  • one operates in continuous X-ray radiation (FIG. 8).
  • This operating mode In this operating mode, it operates in real time, that is to say without any information storage.
  • the image is presented during the entire addressing period, then erased; then again, a second image is addressed, and so on.
  • the duration of a cycle can be 20 ms, thus making the presentation of the image compatible with a shooting by photo camera or television camera (marks 26 and 28 in FIG. 4).
  • the frequency of the maintenance voltage, its amplitude, the duration of addressing, the image frequency (or duration of a complete cycle), the dose X, the acceleration voltage of the addressing electrons are all parameters which allow the presentation of the image to be adapted to the use made of it.

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  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
EP82401670A 1981-09-22 1982-09-14 Tube intensificateur d'images à mémoire, et mode de mise en oeuvre Expired EP0075512B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8117848A FR2513438A1 (fr) 1981-09-22 1981-09-22 Tube intensificateur d'images a memoire et mode de mise en oeuvre
FR8117848 1981-09-22

Publications (2)

Publication Number Publication Date
EP0075512A1 EP0075512A1 (fr) 1983-03-30
EP0075512B1 true EP0075512B1 (fr) 1985-01-23

Family

ID=9262360

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82401670A Expired EP0075512B1 (fr) 1981-09-22 1982-09-14 Tube intensificateur d'images à mémoire, et mode de mise en oeuvre

Country Status (5)

Country Link
US (1) US4680461A (enrdf_load_stackoverflow)
EP (1) EP0075512B1 (enrdf_load_stackoverflow)
JP (1) JPS5866241A (enrdf_load_stackoverflow)
DE (1) DE3262058D1 (enrdf_load_stackoverflow)
FR (1) FR2513438A1 (enrdf_load_stackoverflow)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5404072A (en) * 1993-05-28 1995-04-04 Itt Corporation Unistructural housing for an image intensifier tube
WO1995009432A1 (en) * 1993-05-28 1995-04-06 International Standard Electric Corp. Unistructural housing for an image intensifier tube
JP2002365662A (ja) * 2001-06-11 2002-12-18 Rohm Co Ltd 表示媒体、表示素子、および表示装置
US10492249B2 (en) * 2012-07-10 2019-11-26 Michael M McRae Electroluminescent ornaments and display systems

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3908148A (en) * 1973-12-27 1975-09-23 Watkins Johnson Co Electro-optical transducer and storage tube
FR2431184A1 (fr) * 1978-07-10 1980-02-08 Tektronix Inc Tube de stockage electro-luminescent a rayons cathodiques

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3590253A (en) * 1969-06-30 1971-06-29 Westinghouse Electric Corp Solid-state photoconductor-electroluminescent image intensifier
US3710081A (en) * 1971-06-14 1973-01-09 Tamar Electronics Ind System for computing the average of successive traffic measurements
FR2195841B1 (enrdf_load_stackoverflow) * 1972-08-11 1975-03-07 Thomson Csf
US3967112A (en) * 1973-06-15 1976-06-29 Sharp Kabushiki Kaisha Photo-image memory panel and activating method thereof
US3971931A (en) * 1975-01-23 1976-07-27 The United States Of America As Represented By The Secretary Of The Navy Led image tube light valve
US4206460A (en) * 1977-03-10 1980-06-03 Sharp Kabushiki Kaisha EL Display drive controlled by an electron beam
US4149108A (en) * 1977-06-17 1979-04-10 International Business Machines Corporation Multistable cathode ray type storage display device
US4207617A (en) * 1977-06-29 1980-06-10 Sharp Kabushiki Kaisha Memory erase and memory read-out in an EL display panel controlled by an electron beam
US4155030A (en) * 1977-12-19 1979-05-15 International Business Machines Corporation Multicolor display device using electroluminescent phosphor screen with internal memory and high resolution
US4184069A (en) * 1978-03-28 1980-01-15 The United States Of America As Represented By The Secretary Of The Army Orthogonal array faceplate wafer tube display
US4221002A (en) * 1978-11-06 1980-09-02 International Business Machines Corporation Electro-optically matrix-addressed electroluminescence display with memory
GB2050777A (en) * 1979-05-29 1981-01-07 Tektronix Inc Electroluminescent Storage CRT Display Device and Operating Method
DE2929745C2 (de) * 1979-07-23 1986-03-27 Siemens AG, 1000 Berlin und 8000 München Verfahren zur Herstellung eines Eingangsleuchtschirms eines Röntgenbildverstärkers

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3908148A (en) * 1973-12-27 1975-09-23 Watkins Johnson Co Electro-optical transducer and storage tube
FR2431184A1 (fr) * 1978-07-10 1980-02-08 Tektronix Inc Tube de stockage electro-luminescent a rayons cathodiques

Also Published As

Publication number Publication date
JPS5866241A (ja) 1983-04-20
US4680461A (en) 1987-07-14
DE3262058D1 (en) 1985-03-07
FR2513438A1 (fr) 1983-03-25
EP0075512A1 (fr) 1983-03-30
FR2513438B1 (enrdf_load_stackoverflow) 1983-12-02

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