Cathodo-luminescent display panel

• US 3,904,923 A
• Filed: 01/14/1974
• Issued: 09/09/1975
• Est. Priority Date: 01/14/1974
• Status: Expired due to Term

• Current Assignee: James W. Schwartz
• Original Assignee: James W. Schwartz
• Inventors: Schwartz, James W.
• Primary Examiner(s): Lawrence, James W.
• Assistant Examiner(s): LaRoche, E. R.
• Application Number:
  US05/433,186
• Time in Patent Office: 603 Days
• Field of Search: 313/103-105,68,204 315/11,12,169R,169TV 178/7.3D,7.5D 250/213R
• US Class Current: 348/797
• CPC Class Codes: H01J 29/467 Control electrodes for flat display tubes, e.g. of the type covered by group H01J31/123
• CPC Class Codes: H01J 31/128 provided with control means permitting the electron beam to reach selected parts of the screen, e.g. digitally controlled display tubes H01J31/123 takes precedence
• CPC Class Codes: H01J 43/10 Dynodes H01J43/24, H01J43/26 take precedence

Abstract

This disclosure depicts cathodo-luminescent devices and luminescent panels employing X-Y matrices of such devices as the display elements. The cathodo-luminescent devices are depicted as each comprising a two-section cell containing an ionizable gas at very low pressure. The first section comprises an electronmultiplier serving as a controllable source of free electrons. Free electrons are drawn from the electron-multiplier and accelerated in the second section to high energies whereupon they collide with a light-emissive phosphor screen. Other structures including means for modulating the flow of electrons to the screen are disclosed.

Claims

1. A cathodo-luminescent device comprising:

wall means defining an enclosure containing an ionizable gas at a predetermined low pressure;

an electron-multiplier located within said enclosure for creating at an output end thereof a source of electrons, said electron-multiplier including cathode means and electronmultiplier anode means adapted to receive an applied potential different thereacross, said electron-multiplier generating positive gas ions as a result of collisions between electrons and the gas atoms, said electron-multiplier being constructed to provide a clear path for ions such that some of said ions feed back to said cathode to cause said cathode to emit electrons;

phosphor means disposed at one end of said enclosure in spaced relation to said output end of said electron-multiplier for emitting light when bombarded by high energy electrons;

accelerating anode means disposed at said phosphor means and adapted to receive a predetermined accelerating voltage substantially more positive than the voltage applied to said electron-multiplier means for drawing electrons from said electron-multiplier when said electron-multiplier is on and for accelerating them to high energies for impingement on said phosphor means, the said predetermined gas pressure being sufficiently low as to preclude the establishment of a gas discharge in said device; and

activating means for selectively causing the feedback loop gain of said electro-multiplier to be at leAst unity to drive said electron-multiplier to an on state associated with a predetermined high level of available electron-multiplier current and for selectively causing the feedback loop gain of said electron-multiplier to be less than unity to drive said electron-multiplier to an off state associated with negligible electron-multiplier current.

2. The device defined by claim 1 wherein said electron-multiplier comprises a plurality of discrete, serially arranged, secondary-electron-emissive dynodes disposed between said cathode means and said electron-multiplier anode means and adapted to receive applied voltages ever-increasing in positive polarity in a direction away from said cathode, but substantially less than the voltage applied to said accelerating anode means, said electron-multiplier including an ion-generation region in which said positive gas ions are generated, said dynodes being arranged so as to permit some of said positive gas ions generated in said electron-multiplier to be accelerated to said cathode means to cause said cathode means to emit additional free electrons.

3. The device defined by claim 1 including control means responsive to an applied control voltage for modulating the flow of electrons to said phosphor means and thus the amplitude of the light emitted by said phosphor means.

4. The device defined by claim 1 wherein said device includes baffle means disposed between said electron-multiplier and said accelerating anode means for blocking high energy electrons which might be emitted by said electron-multiplier and for blocking the passage to said cathode means of ions which might be generated in the region between said baffle means and said accelerating anode means.

5. A cathodo-luminescent device comprising:

wall means defining an enclosure containing an ionizable gas at a predetermined low pressure;

an electron-multiplier located within said enclosure for creating at an output end thereof a source of electrons, said electron-multiplier comprising a cathode and an electron-multiplier anode adapted to receive an applied potential difference thereacross, said electron-multiplier including a plurality of discrete, serially arranged, secondary-electron-emissive dynodes disposed between said cathode and said anode and adapted to receive applied voltages ever-increasing in a positive polarity in a direction away from said cathode, said electron-multiplier including an ion-generation region in which positive gas ions are generated as a result of collisions between electrons and said gas, said dynodes being arranged so as to permit said positive gas ions to be accelerated to said cathode to cause said cathode to emit additional free electrons and thereby complete a regenerate electron-ion feedback loop;

phosphor means disposed at one end of said enclosure in spaced relation to said output end of said electron-multiplier for emitting light when bombarded by high energy electrons;

accelerating anode means disposed at said phosphor means and adapted to receive a predetermined accelerating voltage substantially higher than the voltage applied to said electron-multiplier anode for drawing electrons from said electron-multiplier when said electron-multiplier is on and for accelerating them to high energies for impingement on said phosphor means, the said predetermined gas pressure being sufficiently low as to preclude the establishment of a gas discharge in said device;

activating means for selectively causing the loop gain of said electron-multiplier feedback loop to be less than unity to cause said electron-multiplier to assume an inactive state or for turning said electron-multiplier on by causing said loop gain to be unity or greater wherein said electron-multiplier saturates at a predetermined saturation current level; and

control means including a control electrode located within said enclosure between said electron-multiplier and said accelerating anode, said control means being responsive to an applied contrOl voltage for modulating the flow of electrons from said electron-multiplier to said phosphor means and thus the amplitude of the light emitted by said phosphor means.

6. The device defined by claim 5 wherein said device includes baffle means disposed between said electron-multiplier and said accelerating anode for blocking high energy electrons which might be emitted by said electron-multiplier and for blocking the passage to said cathode of ions which might be generated in the region between said baffle means and said accelerating anode.

7. Television display panel for reproducing an image carried by an input video signal, comprising:

an array of cathodo-luminescent elements discretely excitable by row-column selective addressing, each element comprising;

wall means defining at least a portion of an enclosure containing an ionizable gas at a predetermined low pressure, an electron-multiplier located within said enclosure for creating at an output end thereof a source of electrons, said electron-multiplier comprising a cathode and an electron-multiplier anode adapted to receive an applied potential difference thereacross, said electron-multiplier including a plurality of discrete, serially arranged, secondary-electron-emissive dynodes disposed between said cathode and said anode and adapted to receive applied voltages ever-increasing in a positive polarity in a direction away from said cathode, said electron-multiplier including an ion-generation region in which positive gas ions are generated as a result of collisions between electrons and said gas, said dynodes being arranged so as to permit said positive gas ions to be accelerated to said cathode to cause said cathode to emit additional free electrons and thereby complete a regenerate electron-ion feedback loop, phosphor means disposed at one end of said enclosure in spaced relation to said output end of said electron-multiplier for emitting light when bombarded by high energy electrons, accelerating anode means adapted to receive a predetermined accelerating voltage substantially higher than the voltage applied to said electron-multiplier anode for drawing electrons from said electron-multplier when said electron-multiplier is on and for acccelerating them to high energies for impingement on said phosphor means, the said predetermined gas pressure being sufficiently low as to preclude the establishment of a gas discharge in said device, activating means for sectively causing the loop gain of said electron-multiplier feedback loop to be less than unity to cause said electron-multiplier to assume an inactive state or for turning said electron-multiplier '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' by causing said loop gain to be unity or greater wherein said electron-multiplier saturates at a predetermined saturation current level, and control means including a control electrode located within said enclosure between said electron-multiplier and said accelerating anode, said control means being responsive to an applied control voltage for modulating the flow of electrons from said electron-multiplier to said phosphor means and thus the amplitude of the light emitted by said phosphor means; and

means responsive to the input signal and coupled to both said control means and to said activating means associated with each of said elements for storing a predetermined interval of said input signal and for subsequently applying the stored information in parallel to appropriate elements in said array of elements such that said input signal is reproduced on the panel as a light image spatially varying in amplitude.

8. The device defined by claim 7 wherein said panel includes baffle means disposed between said electron-multiplier and said accelerating anode for blocking high energy electrons which might be emitted by said electron-multiplier and for blocking the passage to said cathode of ions which might be generated in the region between said baffle means and said accelerating anode.

9. A luminescent panel for Displaying alpha-numeric characters or other light representations carried by an input signal, comprising:

an array of discretely excitable cathodo-luminescent elements, each element comprising;

wall means defining at least a portion of an enclosure containing an ionizable gas at a predetermined low pressure, an electron-multiplier located within said enclosure for creating at an output end thereof a source of electrons, said electron-multiplier including cathode means and electron-multiplier anode means adapted to receive an applied potential difference thereacross, said electron-multiplier generating positive gas ions as a result of collisions between electrons and the gas atoms, some of which ions feed back to said cathode to cause said cathode to emit electrons, phosphor means disposed at one end of said enclosure in spaced relation to said output end of said electron-multiplier for emitting light when bombarded by high energy electrons, accelerating anode means disposed at said phosphor means and adapted to receive a predetermined accelerating voltage substantially more positive than the voltage applied to said electron-multiplier anode means for drawing electrons from said electron-multiplier when said electron-multiplier is on and for accelerating them to high energies for impingement on said phosphor means, the said predetermined gas pressure being sufficiently low as to preclude the establishment of a gas discharge in said device, and activating means for driving said electron-multiplier between an on state associated with a predetermined maximum available electron-multiplier current and an off state associated with negligible electron-multiplier current; and

means responsive to the input signal and coupled to said electron-multiplier of each of said elements for applying the input signal to said array of elements to cause the input signal to be reproduced on the panel as a light representation spatially varying in amplitude.

10. A cathodo-luminescent device comprising:

wall means defining an enclosure containing an ionizable gas at a predetermined low pressure;

an electron-multiplier located within said enclosure for creating at an output end thereof a source of electrons, said electron-multiplier including cathode means and electrode-multiplier anode means adapted to receive an applied potential difference thereacross, said electron-multiplier generating positive gas ions as a result of collisions between electrons and the gas atoms, said electron-multiplier being constructed to provide a clear path for ions such that some of said ions feed back to said cathode to cause said cathode to emit electrons;

phosphor means disposed at one end of said enclosure in spaced relation to said output end of said electron-multiplier for emitting light when bombarded by high energy electrons;

accelerating anode means disposed at said phosphor means and adapted to receive a predetermined accelerating voltage substantially more positive than the voltage applied to said electron-multiplier means for drawing electrons for said electron-multiplier when said electron-multiplier is on and for accelerating them to high energies for impingement on said phosphor means, the said predetermined gas pressure being sufficiently low as to preclude the establishment of a gas discharge in said device;

activating means for selectively causing the feedback loop gain of said electron-multiplier to be at least unity to drive said electron-multiplier to an on state associated with a predetermined high level of available electron-multiplier current and for selectively causing the feedback loop gain of said electron-multiplier to be less than unity to drive said electron-multiplier to an off state associated with negligible electron-multiplier current; and

beam deflecting means responsive to an applied deflection voltage for vertically deflecting the electron beam to a different vertical location on said phosphor means.

11. Television display panel for reproducing an image carried by an input video signal, comprising:

an array of cathodo-luminescent elements discretely excitable by row-column selective addressing, each element comprising;

wall means defining at least a portion of an enclosure containing an ionizable gas at a predetermined low pressure, an electron-multiplier located within said enclosure for creating at an output end thereof a source of electrons, said electron-multiplier comprising a cathode and an electron-multiplier anode adapted to receive an applied potential difference thereacross, said electron-multiplier including a plurality of discrete, serially arranged, secondary-electron-emissive dynodes disposed between said cathode and said anode and adapted to receive applied voltages ever-increasing in a positive polarity in a direction away from said cathode, said electron-multiplier including an ion-generation region in which positive gas ions are generated as a result of collisions between electrons and said gas, said dynodes being arranged so as to permit said positive gas ions to be accelerated to said cathode to cause said cathode to emit additional free electrons and thereby complete a regenerate electron-ion feedback loop, phosphor means disposed at one end of said enclosure in spaced relation to said output end of said electron-multiplier for emitting light when bombarded by high energy electrons, accelerating anode means adapted to receive a predetermined accelerating voltage substantially higher than the voltage applied to said electron-multiplier anode for drawing electrons from said electron-multiplier when said electron-multiplier is on and for accelerating them to high energies for impingement on said phosphor means, the said predetermined gas pressure being sufficiently low as to preclude the establishment of a gas discharge in said device, activating means for selectively causing the loop gain of said electron-multiplier feedback loop to be less than unity to cause said electron-multiplier to assume an inactive state or for turning said electron-multiplier on by causing said loop gain to be unity or greater wherein said electron-multiplier saturates at a predetermined saturation current level, control means including a control electrode located within said enclosure between said electron-multiplier and said accelerating anode, said control means being responsive to an applied control voltage for modulating the flow of electrons from said electron-multiplier to said phosphor means and thus the amplitude of the light emitted by said phosphor means, and beam deflecting means responsive to an applied interlace deflection voltage for vertically deflecting the electron beam to a different vertical location on said phosphor means to effect interlace of successively displayed fields; and

means responsive to the input signal and coupled to both said control means and to said activating means associated with each of said elements for storing a predetermined interval of said input signal and for subsequently applying the stored information in parallel to appropriate elements in said array of elements such that said input signal is reproduced on the panel as a light image spatially varying in amplitude.