Method and device for implementing subframe display to reduce the pseudo contour in plasma display panels

• US 6,924,778 B2
• Filed: 11/21/2001
• Issued: 08/02/2005
• Est. Priority Date: 06/18/2001
• Status: Expired due to Fees

• Current Assignee: Hitachi Plasma Patent Licensing Company Limited (Hitachi, Ltd.)
• Original Assignee: Fujitsu Limited
• Inventors: Takayama, Kunio, Awamoto, Kenji
• Primary Examiner(s): Lefkowitz, Sumati
• Assistant Examiner(s): LIU, MING HUN
• Application Number:
  US09/989,117
• Publication Number:
  US 20020190925A1
• Time in Patent Office: 1,350 Days
• Field of Search: 345/60, 345/147, 345/63
• US Class Current: 345/60
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0266 Reduction of sub-frame artefacts
• CPC Class Codes: G09G 2320/106 Determination of movement vectors or equivalent parameters within the image
• CPC Class Codes: G09G 3/2029 the sub-frames having non-binary weights
• CPC Class Codes: G09G 3/2051 with use of a spatial dither pattern
• CPC Class Codes: G09G 3/2803 Display of gradations G09G3/288 takes precedence

Abstract

A method for driving a plasma display panel is provided in which dynamic pseudo contours are reduced and pattern noises are suppressed so that image quality of an animation display is improved. In the method, a superposition method is applied only to the area of a display image, which is made of pixels having a gradation at which only one of plural subframes having the same luminance weight concerning the superposition method is lighted and has a luminance gradient within a preset value range between the neighboring pixels.

Claims

1. A method for driving a plasma display panel by replacing a frame with a plurality of subframes having weights of luminance and by setting light emission of cells on and off for each subframe so as to realize a gradation display, the method comprising:

assigning a luminance weight to each of the subframes so that plural subframe expressions, as combinations of subframes to be lighted, are prepared for a specific gradation; and

applying a superposition method in which the plural subframe expressions are mixed only to the specific area that is included in the frame, is made of pixels having the specific gradation and has a luminance gradient within a preset value range between the neighboring pixels.

2. The method according to claim 1, wherein the specific area is an area larger than a predetermined value.

3. A method for driving a plasma display panel by replacing a frame with a plurality of subframes having weights of luminance and by setting light emission of cells on and off for each subframe so as to realize a gradation display, the method comprising:

assigning a luminance weight to each of the subframes so that plural subframe expressions, as combinations of subframes to be lighted, are prepared for a specific gradation; and

applying a superposition method in which the plural subframe expressions are mixed only to the specific area that is included in the frame, made of pixels having the specific gradation and has a luminance gradient within a preset value range between the neighboring pixels and is a portion of a moving object different from a previous frame.

4. The method according to claim 3, wherein the specific area is an area larger than a predetermined value.

5. A device for driving a plasma display panel by replacing a frame with a plurality of subframes and by setting light emission of cells on and off for each subframe so as to realize a gradation display, wherein:

the device comprises an area decision circuit dividing the frame into a specific area that is made of pixels having a specific gradation and a luminance gradient within a preset value range between neighboring pixels and other areas, and

the device performs a light emission control for the specific area of the frame by applying a superposition method in which plural subframe expressions are mixed while performing another light emission control for other areas without applying the superposition method.

6. A device for driving a plasma display panel by replacing a frame with a plurality of subframes and by setting light emission of cells on and off for each subframe so as to realize a gradation display, wherein:

the device comprises an area decision circuit dividing the frame into a specific area that is made of pixels having a specific gradation and a luminance gradient within a preset value range between the neighboring pixels and is a portion of a moving object, different from a previous frame and other areas, and

the device performs a light emission control for the specific area of the frame by applying a superposition method in which plural subframe expressions are mixed while performing another light emission control for other areas without applying the superposition method.

7. A display device, comprising:

an AC type plasma display panel; and

a driving device driving the plasma display panel and comprising;

an area decision circuit dividing the frame into a specific area that is made of pixels having a specific gradation and a luminance gradient within a preset value range between neighboring pixels and other areas, and

the driving device performs a light emission control for the specific area of the frame by applying a superposition method in which plural subframe expressions are mixed while performing another light emission control for other areas without applying the superposition method.

8. A display device, comprising:

an AC type plasma display panel; and

a driving device driving the plasma display panel and comprising;

an area decision circuit dividing the frame into a specific area that is made of pixels having a specific gradation and luminance gradient within a preset value range between neighboring pixels and is a portion of a moving object different from a previous frame and other areas, and

the driving device performs a light emission control for the specific area of the frame by applying a superposition method in which plural types of subframe expressions are mixed while performing another light emission control for other areas without applying the superposition method.