Image display apparatus and display control method

• US 6,552,702 B1
• Filed: 02/24/2000
• Issued: 04/22/2003
• Est. Priority Date: 02/26/1999
• Status: Expired due to Fees

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Abe, Naoto, Yamazaki, Tatsuro
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): Nguyen, Jennifer T.
• Application Number:
  US09/512,640
• Time in Patent Office: 1,153 Days
• Field of Search: 345/76, 345/77, 345/78, 345/74.1, 345/75.1, 345/75.2, 345/98, 345/100
• US Class Current: 345/75.2
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• 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
• CPC Class Codes: H01J 2201/3165 Surface conduction emission type cathodes
• CPC Class Codes: H01J 31/127 using large area or array sources, i.e. essentially a source for each pixel group

Abstract

An image display apparatus performs color adjustment such that the emission luminances of emission substances of respective colors that emit light upon reception of electrons emitted by electron-emitting devices are controlled by controlling the electron amount emitted by the electron-emitting devices. A pulse width-modulated signal corresponding to an image signal is input to the column wiring of a display panel having an electron source with a plurality of electron-emitting devices and fluorescent substances laid out in stripes in correspondence with the respective colors. A horizontal scanning signal for driving a row wiring is input to the row wiring in synchronism with image display. The pulse width-modulated signal is driven by voltages from different power sources in units of the respective colors. The output voltages of the power sources are changed to control the driving voltages of the electron-emitting devices for irradiating fluorescent substances corresponding to the respective colors with electrons.

Claims

1. An image display apparatus comprising:

an electron source having a plurality of electron-emitting devices arranged in a matrix form;

a plurality of column direction wirings each of which is connected to electron-emitting devices arranged in each column of said plurality of electron-emitting devices;

emission means, having emission substances corresponding to respective colors, for emitting light upon reception of electrons emitted by said electron source, thereby displaying a color image;

modulation means for outputting a pulse signal having a modulated pulse width corresponding to an image signal; and

a plurality of voltage control means each of which is assigned to a different color to change a voltage of the pulse signal for driving each of the electron-emitting devices for irradiating the emission substances corresponding to its assigned color with electrons,

wherein each of said plurality of voltage control means is provided commonly to said plurality of column direction wirings in its assigned color unit and is capable of changing the voltage of the pulse signal for its assigned color independently to adjust that color, and

wherein the pulse signal corresponding to each color is applied to each of said plurality of column direction wirings.

3. The apparatus according to claim 1 further comprising instruction means for instructing adjustment of a display color, and said voltage control means controls the voltage of the pulse signal in accordance with an instruction from said instruction means.

4. The apparatus according to claim 1, wherein said plurality of electron-emitting devices are laid out in a matrix, and said emission substances corresponding to the respective colors are laid out in stripes in units of colors.

5. The apparatus according to claim 4, further comprising scanning driving means for selecting respective scanning lines of said plurality of electron-emitting devices, and applying a predetermined voltage to the selected scanning lines.

6. The apparatus according to claim 4, wherein the pulse signal output from said modulation means is input to a column wiring of the matrix.

7. The apparatus according to claim 1, wherein said emission substances corresponding to the respective colors are R, G, and B fluorescent substances.

8. The apparatus according to claim 1, wherein said electron-emitting device is a cold cathode device.

9. The apparatus according to claim 8, wherein said electron-emitting device is an FE type electron-emitting device.

10. The apparatus according to claim 8, wherein said electron-emitting device is an MIM type electron-emitting device.

11. The apparatus according to claim 1, wherein said electron-emitting device is a surface-conduction emission type electron-emitting device.

2. An image display apparatus comprising:

an electron source having a plurality of electron-emitting devices arranged in a matrix form;

a plurality of column direction wirings each of which is connected to electron-emitting devices arranged in each column of said plurality of electron-emitting devices;

emission means, having emission substances corresponding to respective colors, for emitting light upon reception of electrons emitted by said electron source, thereby displaying a color image;

modulation means for outputting a pulse signal having a pulse width corresponding to an image signal;

a plurality of current control means each of which is assigned to a color to change a current of the pulse signal for driving each of the electron-emitting devices for irradiating the emission substances corresponding to its assigned color with electrons; and

voltage sources for controlling said plurality of current control means respectively provided commonly to said plurality of column direction wirings in its associated color unit,

wherein each of said plurality of current control means is capable of changing the current of the pulse signal for its assigned color independently to adjust that color, and

wherein the pulse signal corresponding to each color is applied to each of said plurality of column direction wirings.

12. A display control method in an image display apparatus having an electron source with a plurality of electron-emitting devices arranged in a matrix form, emission substances corresponding to respective colors, a plurality of column direction wirings each of which is connected to electron-emitting devices arranged in each column of said plurality of electron-emitting devices and emission means for emitting light upon reception of electrons emitted by the electron source to display a color image, comprising:

a modulation step of outputting a pulse signal having a modulated pulse width corresponding to an image signal; and

a voltage control step of changing a voltage of the pulse signal for driving each of the electron-emitting devices for irradiating the emission substances corresponding to the respective colors with electrons,

wherein said voltage control step changes a voltage of the pulse signal by a plurality of voltage control means provided commonly to the plurality of column direction wirings in its assigned color unit,

wherein the voltage of the pulse signal is changeable independently for each color to adjust color displayed in said voltage control step, and

wherein the pulse signal corresponding to each color is applied to each of the plurality of column direction wirings.

13. The method according to claim 12, wherein the method further comprises the instruction step of instructing adjustment of a display color, and the voltage control step comprises controlling the voltage of the pulse signal in accordance with an instruction in the instruction step.

14. A display control method in an image display apparatus having an electron source with a plurality of electron-emitting devices arranged in a matrix form, emission substances corresponding to respective colors, a plurality of column direction wirings each of which is connected to electron-emitting devices arranged in each column of said plurality of electron-emitting devices, and emission means for emitting light upon reception of electrons emitted by the electron source to display a color image, comprising:

a modulation step of outputting a pulse signal having a pulse width corresponding to an image signal; and

a current control step of changing a current of the pulse signal for driving each of the electron-emitting devices for irradiating the emission substances corresponding to the respective colors with electrons,

wherein said current control step changes a current of the pulse signal by a plurality of voltage sources provided commonly to the plurality of column direction wirings in its assigned color unit,

wherein the current of the pulse signal is changeable independently for each color to adjust color displayed in said current control step, and

wherein the pulse signal corresponding to each color is applied to each of the plurality of column direction wirings.

15. An image display apparatus comprising:

a display panel in which devices are arranged at or near intersections of modulated-signal wirings and scanning wirings, and devices connected to a common modulated-signal wiring emit light of the same color;

a control voltage source for supplying an adjustable control voltage corresponding to each color of light emitted by said display panel;

a variable current source which is connected to the modulated-signal wiring, receives from said control voltage source a control voltage corresponding to a color of light emitted by devices connected to the modulated-signal wiring, and outputs a current corresponding to the control voltage to the modulated-signal wiring; and

a modulated-signal driver for modulating the current output from said variable current source into a pulse having a width corresponding to an image signal value.

16. The apparatus according to claim 15, wherein said control voltage source includes a first voltage source for outputting a first voltage adjustable by an operator and a second voltage source for outputting a second voltage corresponding to correction data for correcting an input/output characteristic of each device, and outputs a voltage adjusted by the second voltage based on the first voltage.

17. The apparatus according to claim 15, wherein said display panel has elementary colors laid out in stripes in units of modulated-signal wirings, and said control voltage source is independent for each elementary color.

18. The apparatus according to claim 15, wherein said display panel comprises a fluorescent plate of colors corresponding to the respective devices, and emits light upon collision with an electron beam emitted by the device.

19. The apparatus according to claim 15, wherein the device is a cold cathode device.

20. The apparatus according to claim 19, wherein the cold cathode device is a surface-conduction emission type electron-emitting device.

21. The apparatus according to claim 19, wherein the cold cathode device is a field emission type electron-emitting device.

22. The apparatus according to claim 15, wherein the device is an electroluminescent device.

23. A display control method in an image display apparatus in which devices are arranged at or near intersections of modulated-signal wirings and scanning wirings, and devices connected to a common modulated-signal wiring emit light of the same color, comprising:

the voltage control step of supplying an adjustable control voltage corresponding to each color of light emitted by a display panel;

the variable current output step of receiving a control voltage corresponding to a color of light emitted by devices connected to the modulated-signal wiring, and outputting a current corresponding to the control voltage to the modulated-signal wiring; and

the modulation step of modulating the current output from a variable current source into a pulse having a width corresponding to an image signal value.

24. The method according to claim 23, wherein the voltage control step comprises using a first voltage source for outputting a first voltage adjustable by an operator and a second voltage source for outputting a second voltage corresponding to correction data for correcting an input/output characteristic of each device, and outputting a voltage adjusted by the second voltage based on the first voltage.

25. The method according to claim 23, wherein devices which emit light of the same color are laid out in a stripe, and a control voltage source is independent for each elementary color.

26. The method according to claim 23, wherein light is emitted by causing an electron beam emitted by the device to collide against a fluorescent plate of colors corresponding to the respective devices.

27. The method according to claim 23, wherein the device is a cold cathode device.

28. The method according to claim 27, wherein the cold cathode device is a surface-conduction emission type electron-emitting device.

29. The method according to claim 28, wherein the cold cathode device is a field emission type electron-emitting device.

30. The method according to claim 23, wherein the device is an electroluminescent device.

31. An image display apparatus comprising:

a display panel having devices, modulated-signal wirings and scanning wirings, said devices being connected to a common modulated signal wiring emit light of the same color;

a plurality of control voltage sources each of which is assigned to a color to supply adjustable control voltage corresponding to each color of light emitted by said display panel and is capable of adjusting its assigned color independently; and

a modulated-signal driver which is connected to said modulated-signal wiring, receives from said control voltage source a control voltage corresponding to a color of light emitted by devices connected to the modulated-signal wiring, and outputs the control voltage to the modulated-signal wiring,

wherein said modulated-signal driver modulates the control voltage from said control voltage source into a modulated voltage pulse having a width corresponding to an image signal value, and

wherein each of said plurality of voltage control sources is provided commonly to said modulated signal wirings in its assigned color unit.