Method for driving an addressable matrix display with luminescent pixels, and display apparatus using the method

• US 6,288,695 B1
• Filed: 08/25/1998
• Issued: 09/11/2001
• Est. Priority Date: 08/22/1989
• Status: Expired due to Term

• Current Assignee: Acacia Patent Acquisition Corporation (Acacia Research Corporation)
• Original Assignee: Lawson A. Wood
• Inventors: Wood, Lawson A.
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): NGUYEN, FRANCIS N
• Application Number:
  US09/139,757
• Time in Patent Office: 1,113 Days
• Field of Search: 345/55, 345/60, 345/74, 345/75, 345/76, 345/87, 345/63, 345/204, 345/75.2, 345/74.1, 345/507, 345/147, 345/84, 348/797, 315/169.1, 315/169.3, 315/167, 313/336, 313/371, 313/495, 313/309
• US Class Current: 345/75.2
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/0267 Details of drivers for scan electrodes, other than drivers for liquid crystal, plasma or OLED displays
• 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 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2330/028 Generation of voltages supplied to electrode drivers in a matrix display other than LCD
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/2081 with combination of amplitude modulation and time modulation space and time error diffusion G09G3/2066
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: G09G 3/34 by control of light from an independent source
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833
• CPC Class Codes: G09G 3/3629 using liquid crystals having memory effects, e.g. ferroelectric liquid crystals
• CPC Class Codes: G09G 5/39 Control of the bit-mapped memory

Abstract

A display apparatus employs a field emission display device with pixels which are turned on and off in accordance with different bits of video words that are being displayed. The field emission display device is driven so that its pixels emit light at different intensity levels, depending upon the rank of the bits that are being displayed.

Claims

1. A method for displaying an image on an addressable matrix, field emission display device having gate electrodes and having luminescent pixels at an anode electrode, the image being specified by video words having least significant bits and most significant bits, comprising:

(a) associating the pixels of the display device with corresponding video words;

(b) selecting pixels of the display device that are to be illuminated using the least significant bits of the corresponding the video words;

(c) exciting the pixels selected during step (b) so that they glow at a first light intensity level;

(d) selecting pixels of the display device that are to be illuminated using the most significant bits of the corresponding video words; and

(e) exciting the pixels selected during step (d) so that they glow at a second light intensity level that is higher than the first light intensity level,

wherein step (e) comprises changing an anode voltage that is applied to the anode electrode.

2. The method of claim 1, wherein steps (b) and (c) are conducted at a faster rate than steps (d) and (e).

3. The method of claim 2, wherein the video words additionally have LSB+X intermediate bits with bit ranks between the LSB bits and the MSB bits, X being an integer, and wherein the method further comprises steps (f) selecting pixels of the display device that are to be illuminated using the LSB+X intermediate bits of the corresponding video words, and (g) exciting the pixels selected during step (f) so that they glow at a third light intensity level that is between the first and second light intensity levels.

4. The method of claim 3, wherein steps (f) and (g) are conducted at a rate that is different from steps (b) and (c) and also different from steps (d) and (e).

5. The method of claim 1, wherein the second light intensity level is about a power of two times larger than the first light intensity level.

6. The method of claim 1, wherein step (e) further comprises also changing the gate voltage.

7. A method for displaying an image on a field emission display device having an anode electrode, gate electrodes, and cathode electrodes, the gate electrodes and cathode electrodes of the display device crossing at pixel locations of the display device, the image being specified by video words having least significant bits and most significant bits, comprising:

(a) associating the pixel locations of the display device with corresponding video words;

(b) using the least significant bits of the video words to select cathode electrodes at pixel locations corresponding to the video words;

(c) applying an anode voltage to the anode electrode, strobing the gate electrodes, and establishing a predetermined potential difference between the cathode electrodes selected in step (b) and the strobed gate electrodes;

(d) using the most significant bits of the video words to again select cathode electrodes at pixel locations corresponding to the video words; and

(e) applying an anode voltage to the anode electrode, strobing the gate electrodes, and establishing a predetermined potential difference between the cathode electrodes selected in step (d) and the strobed gate electrodes,

wherein both of the anode voltage and the potential difference employed in step (e) are different from the anode voltage and the potential different employed in step (c).

8. The method of claim 7, wherein steps (b) and (c) are conducted at a faster rate than steps (d) and (e).

9. A method for displaying an image on an addressable matrix display device having luminescent pixels, the image being specified by video words having least significant bits and most significant bits, comprising:

(a) associating the pixels of the display device with corresponding video words;

(b) selecting pixels of the display device that are to be illuminated using the least significant bits of the corresponding the video words;

(c) exciting the pixels selected during step (a) so that they glow at a first light level;

(d) selecting pixels of the display device that are to be illuminated using the most significant bits of the corresponding video words; and

(c) exciting the pixels selected during step (d) so that they glow at a second light intensity level that is higher than the first light intensity level,

wherein steps (b) and (c) arc conducted at a faster rate than steps (d) and (e).

10. The method of claim 9, wherein the display device is a field emission display device having an anode electrode and cathode electrodes, wherein step (c) comprises applying a predetermined cathode voltage on selected cathode electrodes and applying a predetermined anode voltage on the anode electrode, and wherein step (e) comprises changing at least one of the cathode and anode voltages.

11. The method of claim 10, wherein step (e) comprises changing both the cathode and anode voltages.

12. A method for displaying an image on a field emission display device having an anode electrode, gate electrodes, and cathode electrodes, the gate electrodes and cathode electrodes of the display device crossing at pixel locations of the display device, the image being specified by video words having least significant bits and most significant bits, comprising:

(a) associating the pixel locations of the display device with corresponding video words;

(b) using the least significant bits of the video words to select cathode electrodes at pixel locations corresponding to the video words;

(c) applying an anode voltage to the anode electrode, strobing the gate electrodes, and establishing a predetermined potential difference between the cathode electrodes selected in step (b) and the strobed gate electrodes;

(d) using the most significant bits of the video words to again select cathode electrodes at pixel locations corresponding to the video words; and

(e) applying an anode voltage to the anode electrode, strobing the gate electrodes, and establishing a predetermined potential difference between the cathode electrodes selected in step (d) and the strobed gate electrodes,

wherein at least one of the anode voltage and the potential difference employed in step (e) is different from the anode voltage and the potential different employed in step (c), and

wherein steps (b) and (c) are conducted at a faster rate than steps (d) and (e).