Display and method of driving display

• US 20050057175A1
• Filed: 08/16/2004
• Published: 03/17/2005
• Est. Priority Date: 08/22/2003
• Status: Abandoned Application

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Nanataki, Tsutomu, Takeuchi, Yukihisa, Ohwada, Iwao
• Application Number:
  US10/919,678
• Publication Number:
  US 20050057175A1
• Time in Patent Office: Days
• US Class Current: 315/169.300
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/22 using controlled light sources

Abstract

A drive circuit has a drive voltage generating circuit for generating a drive voltage, to be applied between a first electrode and a second electrode of a corresponding electron emitter, based on a selection signal from a corresponding selection line. The drive circuit further includes a modulation circuit for stepwise modulating the amplitude of a drive pulse based on a pixel signal from a corresponding signal line, for thereby controlling the luminance gradation of a corresponding pixel, wherein the drive voltage has a waveform including a drive pulse appearing in timed relation to a selection instruction from the selection line, and wherein the drive pulse, having a predetermined amplitude level, is applied between the first electrode and the second electrode, to cause at least part of an emitter to invert or change the polarization thereof to emit electrons from the electron emitter.

Claims

1. A display comprising:

a plurality of electron emitters arrayed in association with respective pixels;

at least one selection line for supplying an instruction to select or not select each of said electron emitters;

at least one signal line for supplying a pixel signal to a selected one of said electron emitters; and

a drive section having a plurality of drive circuits arrayed in association with said electron emitters, respectively, for driving electron emitters based on the instruction from one of said at least one selection line and the pixel signal from one of said at least one signal line;

each of said electron emitters comprising;

an emitter made of a dielectric material; and

a first electrode and a second electrode mounted on said emitter;

each of said drive circuits comprising;

a drive voltage generating circuit for generating a drive voltage to be applied between said first electrode and said second electrode of a corresponding one of the electron emitters based on the instruction from a corresponding one of said at least one selection line; and

a modulation circuit for modulating the amplitude of a drive pulse stepwise based on the pixel signal from a corresponding one of said at least one signal line for thereby controlling the luminance gradation of a corresponding pixel, if said drive voltage has a waveform including said drive pulse appearing in timed relation to the instruction from said selection line and the drive pulse having a predetermined amplitude level is applied between said first electrode and said second electrode to cause at least part of said emitter to invert or change the polarization thereof to emit electrons from said electron emitter.

2. A display according to claim 1, further comprising:

a collector electrode disposed in facing relation to said electron emitters; and

a plurality of fluorescent layers spaced from said electron emitters by respective intervals.

3. A display according to claim 1, wherein the electrons are emitted from the emitter near said first electrode, and said first electrode has a potential lower than the potential of said second electrode during a period in which said drive pulse is applied.

4. A display according to claim 1, wherein said drive voltage generated by said drive voltage generating circuit has a waveform including a drive pulse having a first amplitude which is not sufficient enough to emit electrons from said electron emitter in timed relation to the instruction from said selection line, and said modulation circuit maintains the amplitude of said drive pulse as said first amplitude if said pixel signal is a signal representing the extinguishing of light, and sets the amplitude of said drive pulse to a second amplitude which is sufficient enough to emit electrons from said electron emitter and modulates the pulse duration of said second amplitude based on a gradation component included in said pixel signal if said pixel signal is a signal representing the emission of light.

5. A display according to claim 4, wherein the following relationship is satisfied:

τ

d=τ

1+τ

2
|V2|>

|V1|

where τ

d represents the pulse duration of said drive pulse, V1 said first amplitude of said drive pulse, V2 said second amplitude of said drive pulse, τ

1 the pulse duration of said first amplitude, and τ

2 the pulse duration of said second amplitude.

6. A display according to claim 1, wherein said modulation circuit modulates the amplitude of said drive pulse into a first amplitude which is not sufficient enough to emit electrons from said electron emitter if said pixel signal is a signal representing the extinguishing of light, and sets the amplitude of said drive pulse to a second amplitude which is sufficient enough to emit electrons from said electron emitter and modulates the pulse duration of said second amplitude based on a gradation component included in said pixel signal if said pixel signal is a signal representing the emission of light.

7. A display according to claim 6, wherein the following relationship is satisfied:

τ

d=τ

1+τ

2
|V2|>

|V1|

where τ

d represents the pulse duration of said drive pulse, V1 said first amplitude of said drive pulse, V2 said second amplitude of said drive pulse, τ

1 the pulse duration of said first amplitude, and τ

2 the pulse duration of said second amplitude.

8. A display according to claim 1, wherein said emitter is made of a piezoelectric material or an electrostrictive material, and if the period of one frame includes a selection period and a non-selection period, then at least one said drive pulse is applied between said first electrode and said second electrode in said selection period, and a voltage such that said first electrode has a potential higher than the potential of said second electrode is applied between said first electrode and said second electrode in said non-selection period.

9. A display according to claim 8, wherein said emitter is polarized by an electric field in such a direction that the potential of said first electrode is lower than the potential of said second electrode during said selection period, and said emitter is polarized by an electric field in such a direction that the potential of said second electrode is lower than the potential of said first electrode during said non-selection period.

10. A display according to claim 1, wherein said emitter is made of an electrostrictive material, and if said drive voltage is output in a period including a selection period and a non-selection period, then a reset voltage such that said first electrode has a potential higher than the potential of said second electrode is applied between said first electrode and said second electrode immediately before said selection period, at least one said drive pulse is applied between said first electrode and said second electrode in said selection period, and an arbitrary voltage between at least said reset voltage and the voltage of said drive pulse is applied between said first electrode and said second electrode in said non-selection period, and said selection period starts after said reset voltage is applied.

11. A display according to claim 10, wherein said emitter is polarized by an electric field in such a direction that the potential of said first electrode is higher than the potential of said second electrode under said reset voltage.

12. A method of driving a display having:

a plurality of electron emitters arrayed in association with respective pixels;

at least one selection line for supplying an instruction to select or not select each of said electron emitters;

at least one signal line for supplying a pixel signal to a selected one of said electron emitters; and

a drive section having a plurality of drive circuits arrayed in association with said electron emitters, respectively, for driving electron emitters based on the instruction from one of said at least one selection line and the pixel signal from one of said at least one signal line;

each of said electron emitters comprising an emitter made of a dielectric material and a first electrode and a second electrode mounted on said emitter;

said method comprising the steps of;

generating a drive voltage to be applied between said first electrode and said second electrode of a corresponding one of the electron emitters based on the instruction from a corresponding one of said at least one selection line, and

modulating the amplitude of a drive pulse stepwise based on the pixel signal from a corresponding one of said at least one signal line for thereby controlling the luminance gradation of a corresponding pixel, if said drive voltage has a waveform including said drive pulse appearing in timed relation to the instruction from said selection line and the drive pulse having a predetermined amplitude level is applied between said first electrode and said second electrode to cause at least part of said emitter to invert or change the polarization thereof to emit electrons from said electron emitter.

13. A method according to claim 12, wherein said display further has a collector electrode disposed in facing relation to said electron emitters, and a plurality of fluorescent layers spaced from said electron emitters by respective intervals.

14. A method according to claim 12, wherein the electrons are emitted from the emitter near said first electrode, and said first electrode has a potential lower than the potential of said second electrode during a period in which said drive pulse is applied.

15. A method according to claim 12, wherein said drive voltage has a waveform including a drive pulse having a first amplitude which is not sufficient enough to emit electrons from said electron emitter in timed relation to the instruction from said selection line, and the amplitude of said drive pulse is maintained as said first amplitude if said pixel signal is a signal representing the extinguishing of light, and the amplitude of said drive pulse is set to a second amplitude which is sufficient enough to emit electrons from said electron emitter and the pulse duration of said second amplitude is modulated based on a gradation component included in said pixel signal if said pixel signal is a signal representing the emission of light.

16. A method according to claim 15, wherein the following relationship is satisfied:

τ

d=τ

1+τ

2
|V2|>

|V1|

where τ

d represents the pulse duration of said drive pulse, V1 said first amplitude of said drive pulse, V2 said second amplitude of said drive pulse, τ

1 the pulse duration of said first amplitude, and τ

2 the pulse duration of said second amplitude.

17. A method according to claim 12, wherein the amplitude of said drive pulse is modulated into a first amplitude which is not sufficient enough to emit electrons from said electron emitter if said pixel signal is a signal representing the extinguishing of light, and the amplitude of said drive pulse is set to a second amplitude which is sufficient enough to emit electrons from said electron emitter and the pulse duration of said second amplitude is modulated based on a gradation component included in said pixel signal if said pixel signal is a signal representing the emission of light.

18. A method according to claim 17, wherein the following relationship is satisfied:

τ

d=τ

1+τ

2
|V2|>

|V1|

where τ

d represents the pulse duration of said drive pulse, V1 said first amplitude of said drive pulse, V2 said second amplitude of said drive pulse, τ

1 the pulse duration of said first amplitude, and τ

2 the pulse duration of said second amplitude.

19. A method according to claim 12, wherein said emitter is made of a piezoelectric material or an electrostrictive material, and if the period of one frame includes a selection period and a non-selection period, then at least one said drive pulse is applied between said first electrode and said second electrode in said selection period, and a voltage such that said first electrode has a potential higher than the potential of said second electrode is applied between said first electrode and said second electrode in said non-selection period.

20. A method according to claim 19, wherein said emitter is polarized by an electric field in such a direction that the potential of said first electrode is lower than the potential of said second electrode during said selection period, and said emitter is polarized by an electric field in such a direction that the potential of said second electrode is lower than the potential of said first electrode during said non-selection period.

21. A method according to claim 12, wherein said emitter is made of an electrostrictive material, and if said drive voltage is output in a period including a selection period and a non-selection period, then a reset voltage such that said first electrode has a potential higher than the potential of said second electrode is applied between said first electrode and said second electrode immediately before said selection period, at least one said drive pulse is applied between said first electrode and said second electrode in said selection period, and an arbitrary voltage between at least said reset voltage and the voltage of said drive pulse is applied between said first electrode and said second electrode in said non-selection period, and said selection period starts after said reset voltage is applied.

22. A method according to claim 21, wherein said emitter is polarized by an electric field in such a direction that the potential of said first electrode is higher than the potential of said second electrode under said reset voltage.