Method and apparatus for displaying gray scale of plasma display panel

• US 6,429,833 B1
• Filed: 09/16/1999
• Issued: 08/06/2002
• Est. Priority Date: 09/16/1998
• Status: Expired due to Fees

• Current Assignee: Samsung Display Devices Co., Ltd. (Samsung SDI Company Limited)
• Original Assignee: Samsung Display Devices Co., Ltd. (Samsung SDI Company Limited)
• Inventors: Kim, Se-woong, Ryeom, Jeong-duk
• Primary Examiner(s): Saras, Steven
• Assistant Examiner(s): MAIER, CHRISTOPHER J
• Application Number:
  US09/397,668
• Time in Patent Office: 1,055 Days
• Field of Search: 345/63, 345/60, 345/148, 345/691, 345/473, 345/474, 345/475, 358/1.9, 348/674
• US Class Current: 345/63
• 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 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 3/2029 the sub-frames having non-binary weights
• CPC Class Codes: G09G 3/2037 with specific control of sub-frames corresponding to the least significant bits
• CPC Class Codes: G09G 3/298 using surface discharge panels

Abstract

A method and apparatus for displaying a gray scale of a plasma display panel, by which generation of a pseudo contour upon expression of a gray scale with respect to a moving picture is prevented when a picture is displayed on a plasma display panel. The method can prevent generation of pseudo contours of dark lines (or bright lines) so that a temporal inconsistency appears as spatial inconsistency, at a portion of a moving picture in which gray scale changes are subtle, when expressing a gray scale by temporal duplication of light emission using the after-image effect of vision. In view of the fact that a pseudo contour is generated because the movement of a pixel is not consistent with the movement of the human eye, and thus a temporal change in luminance is shown as dispersion of luminance on retinas, the present invention redistributes of sub-fields having the luminance of one cell to several cells, as many sub-fields corresponding to the inconsistency of the detected movement of a pixel with the movement of the eye. Accordingly, the movement of a pixel can be approximately consistent with the movement of the eye. Consequently, the retina of the eye can perceive the temporal stimulation of an original picture, so that pseudo contour phenomenon is reduced regardless of the moving speed of a picture.

Claims

1. A method of displaying a gray scale by time-division on a plasma display panel, including:

dividing a picture in each field displayed on the plasma display panel into a plurality of sub-fields such that each sub-field has a temporally different discharge sustaining period to display the gray scale by combinations of the sub-fields;

dispersing and arranging image information representing a picture at an arbitrary position of a first field, to each of the sub-fields constituting the first field, wherein the image information position in each of the sub-fields sequentially moves from a first display position where the image information has been displayed on a field immediately before the first field, to a third display position where the image information is expected to be displayed on a field immediately after the first field, via a second display position where the image information is displayed on the first field; and

,

determining the position of the image information displayed in each of the sub-fields so that the image information sequentially moves from the first display position to the third display position in response to moving speed of the image information among the first, second, and third display positions.

2. The method of claim 1, including determining the image information position on each of the sub-fields so that the image information sequentially moves from the first display position to a position before the second display position in sub-fields corresponding to a first half of a corresponding field, and the image information sequentially moves from the second display position to the third display position in sub-fields corresponding to a second half of the corresponding field.

3. The method of claim 2, including setting the position of the image information in each of the sub-fields at a position where the image information moves, in response to control information determined by characteristic values of sub-fields constituting the corresponding field.

4. The method of claim 2, including determining the position of the image information in each of the sub-fields so that luminance temporally appears consistent or nearly consistent with respect to display time of the corresponding field.

5. The method of claim 4, including determining the discharge sustaining period of each of the sub-fields so that luminance temporally appears consistent or nearly consistent with respect to the display time of the corresponding field.

6. A method of displaying a gray scale by time-division of a plasma display panel, including;

dividing a picture in each field displayed on the plasma display panel into a plurality of sub-fields such that each sub-field has a temporally different discharge sustaining period to display the gray scale by combinations of the sub-fields;

dispersing and arranging image information representing a picture at an arbitrary position of a first field, to each of the sub-fields constituting the first field, wherein the image information position in each of the sub-fields sequentially moves from a first display position where the image information has been displayed on a field immediately before the first field, to a third display position where the image information is expected to be displayed on a field immediately after the first field, via a second display position where the image information is displayed on the first field; and

when a field immediately before the field on which the first display position exists is called a zero order field, and a field just before the zero order field is called a −

1 order field, detecting motion of the zero order field or motions of the zero order and −

1 order fields, estimating position of image information displayed on each of the sub-fields by a motion vector on a straight line or a curve of motion detected between the first and third display positions, via the second display position, and determining image information position displayed on each of the sub-fields by the estimating so that the image information sequentially moves from the first display position to the third display position via the second display position.

7. An apparatus for displaying a gray scale by time-division on a plasma display panel, a picture on each field displayed on the plasma display panel being divided into a plurality of sub-fields, each of the sub-fields having a temporally different discharge sustaining period, the gray scale being displayed by combinations of the different discharge sustaining periods, the apparatus comprising:

a video signal input portion for separating a pure video signal from a composite video signal;

an analog-to-digital (A/D) converter for converting an analog video signal, separated by the video signal input portion, into a digital video signal;

gamma correction means for correcting the digital video signal supplied by the A/D converter for driving a cathode ray tube, to a gamma-corrected signal for driving a plasma display panel;

picture level detection means for detecting total brightness of a picture from the gamma-corrected signal;

a power controller for converting data of a video signal provided by the picture level detection means, the power controller having a power control function;

motion vector detection means for detecting a moving direction and speed of corresponding image information by comparison of image display information received at a corresponding field with image information received at a field prior to the corresponding field, in each field of the gamma-corrected signal;

picture data rearrangement means for dispersing and rearranging pixel data provided by the power controller to several sub-fields according to the moving direction and speed, provided by the motion vector detection means;

a sub-field converter for rearranging pixel data rearranged by the picture data rearrangement means in each sub-field;

pulse timing control means for generating a reference timing signal for a driving pulse for driving electrodes of a plasma display panel based on a signal provided by the power controller;

discharge sustaining pulse generation means for generating a discharge sustaining pulse for driving discharge sustaining electrodes of the plasma display panel based on the reference timing signal provided by the pulse timing control means;

scanning electrode driving means for directly driving scanning electrodes of the plasma display panel using the discharge sustaining pulse; and

address electrode driving means for driving address electrodes of the plasma display panel using the reference timing signal provided by the pulse timing control means and a sub-field video signal provided by the sub-field converter.

8. The apparatus of claim 7, wherein the picture data rearrangement means comprises:

means for moving image information displayed in each of the sub-fields at the speed detected and in the moving direction detected;

means for storing display information moved with respect to information within one field; and

means for reconstructing image information for one field using the display information stored.