Light source

• US 20050040750A1
• Filed: 08/16/2004
• Published: 02/24/2005
• Est. Priority Date: 08/22/2003
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Nanataki, Tsutomu, Akao, Takayoshi, Takeuchi, Yukihisa, Ohwada, Iwao
• Granted Patent: US 7,474,060 B2
• Time in Patent Office: Days
• US Class Current: 313/311
• CPC Class Codes: G09G 3/22 using controlled light sources

Abstract

A light source has a light emission section comprising a two-dimensional array of electron emitters and a drive circuit for applying a drive voltage to each of the electron emitters of the light emission section. The drive circuit applies the drive voltage between upper and lower electrodes of each of the electron emitters based on a control signal representative of turn-on/turn-off from an external source (a turn-on/turn-off switch or the like), for thereby controlling each of the electron emitters. Each of the electron emitters has a plate-like emitter, an upper electrode disposed on a face side of the emitter, and a lower electrode disposed on a reverse side of the emitter.

Claims

1. A light source for emitting light from an electron source by impingement of electrons upon a substance, wherein

said electron source comprises an electron emitter;

and

said electron emitter comprises an emitter of a dielectric material and a first electrode and a second electrode which are disposed on said emitter;

wherein when a drive voltage is applied between said first electrode and said second electrode, at least a portion of said emitter has its polarization inverted or changed to emit electrons.

2. A light source according to claim 1, wherein when said drive voltage is applied between said first electrode and said second electrode, at least the portion of said emitter has its polarization inverted to position positive poles of dipoles around said first electrode to draw primary electrons from said first electrode, and the primary electrons drawn from said first electrode impinge upon said emitter to cause the emitter to emit secondary electrons.

3. A light source according to claim 2, including:

a triple point made up of said first electrode, said emitter, and a vacuum atmosphere;

wherein the primary electrons are drawn from a portion of said first electrode near said triple point, and the primary electrons drawn from said first electrode impinge upon said emitter to cause the emitter to emit secondary electrons.

4. A light source according to claim 1, wherein said emitter is made of a piezoelectric material, an anti-ferrodielectric material, or an electrostrictive material.

5. A light source according to claim 1, including:

means for applying AC pulses between said first electrode and said second electrode to cause at least the portion of said emitter to have its polarization inverted or changed;

wherein electrons are intermittently emitted from said emitter.

6. A light source according to claim 5, wherein before light emitted by a first emission of electrons is extinguished, next electrons are emitted to emit light continuously.

7. A light source according to claim 1, including:

a plurality of said electron emitters, said electron emitters being arranged in a two-dimensional array.

8. A light source according to claim 7, wherein said electron emitters are divided into two groups, further including means for retrieving electric power of the electron emitters in one of the groups with the electron emitters in the other group when the electron emitters in said one group emit light, and retrieving electric power of the electron emitters in said other group with the electron emitters in said one group when the electron emitters in said other group emit light.

9. A light source according to claim 1, including:

means for modulating said drive voltage based on a control signal to control an amount of electrons emitted from said electron emitter for controlling emitted light.

10. A light source according to claim 1, including:

at least two planar light source sections;

each of said planar light source sections having a plurality of said electron emitters which are arranged in a two-dimensional array.

11. A light source according to claim 10, wherein said electron emitters of each of said planar light source sections are divided into two groups, further including means for retrieving electric power of the electron emitters in one of the groups with the electron emitters in the other group when the electron emitters in said one group emit light, and retrieving electric power of the electron emitters in said other group with the electron emitters in said one group when the electron emitters in said other group emit light.

12. A light source according to claim 10, wherein said at least two planar light source sections are divided into two groups, further including means for retrieving electric power of the electron emitters in one of the groups with the electron emitters in the other group when the electron emitters in said one group emit light, and retrieving electric power of the electron emitters in said other group with the electron emitters in said one group when the electron emitters in said other group emit light.

13. A light source according to claim 10, including:

means for modulating the drive voltage applied to the electron emitters of each of said planar light source sections, based on a corresponding control signal, to control an amount of electrons emitted from said electron emitters for controlling emitted light from each of said planar light source sections.

14. A light source for emitting light from an electron source by impingement of electrons upon a substance, wherein

said electron source comprises an electron emitter;

and

said electron emitter comprises an emitter of a dielectric material and a first electrode and a second electrode to which a drive voltage is applied for emitting electrons;

said first electrode being disposed on a first surface of said emitter;

said second electrode being disposed on a second surface of said emitter;

at least said first electrode having a plurality of through regions through which said emitter is exposed;

each of said through regions has a peripheral portion having a surface facing said emitter and spaced from said emitter.

15. A light source according to claim 14, wherein said first electrode emits electrons toward said emitter to charge the emitter in a first stage;

and

said emitter emits electrons in a second stage.

16. A light source according to claim 14, wherein electrons depending on an amount of charges on said emitter in a first stage are emitted from said emitter in a second stage.

17. A light source according to claim 14, wherein an amount of charges on said emitter in a first stage is maintained. until electrons are emitted from said emitter in a second stage.

18. A light source according to claim 14, wherein said emitter is made of a piezoelectric material, an anti-ferrodielectric material, or an electrostrictive material.

19. A light source according to claim 14, including:

means for applying AC pulses between said first electrode and said second electrode to cause at least a portion of said emitter to have its polarization inverted or changed;

wherein electrons are intermittently emitted from said emitter.

20. A light source according to claim 19, wherein before light emitted by a first emission of electrons is extinguished, next electrons are emitted to emit light continuously.

21. A light source according to claim 14, including:

a plurality of said electron emitters, said electron emitters being arranged in a two-dimensional array.

22. A light source according to claim 21, wherein said electron emitters are divided into two groups, further including means for retrieving electric power of the electron emitters in one of the groups with the electron emitters in the other group when the electron emitters in said one group emit light, and retrieving electric power of the electron emitters in said other group with the electron emitters in said one group when the electron emitters in said other group emit light.

23. A light source according to claim 14, including:

means for modulating said drive voltage based on a control signal to control an amount of electrons emitted from said electron emitter for controlling emitted light.

24. A light source according to claim 14, including:

at least two planar light source sections;

each of said planar light source sections having a plurality of said electron emitters which are arranged in a two-dimensional array.

25. A light source according to claim 24, wherein said electron emitters of each of said planar light source sections are divided into two groups, further including means for retrieving electric power of the electron emitters in one of the groups with the electron emitters in the other group when the electron emitters in said one group emit light, and retrieving electric power of the electron emitters in said other group with the electron emitters in said one group when the electron emitters in said other group emit light.

26. A light source according to claim 24, wherein said at least two planar light source sections are divided into two groups, further including means for retrieving electric power of the electron emitters in one of the groups with the electron emitters in the other group when the electron emitters in said one group emit light, and retrieving electric power of the electron emitters in said other group with the electron emitters in said one group when the electron emitters in said other group emit light.

27. A light source according to claim 24, including:

means for modulating the drive voltage applied to the electron emitters of each of said planar light source sections, based on a corresponding control signal, to control an amount of electrons emitted from said electron emitters for controlling emitted light from each of said planar light source sections.