Display control apparatus of display panel, and display device having display control apparatus

• US 7,796,198 B2
• Filed: 02/14/2006
• Issued: 09/14/2010
• Est. Priority Date: 02/24/2005
• Status: Active Grant

• Current Assignee: Maxell, Ltd.
• Original Assignee: Fujitsu Hitachi Plasma Display Limited (Hitachi, Ltd.)
• Inventors: Ikeda, Hiroki, Ueda, Toshio
• Primary Examiner(s): Tran; Trang U
• Application Number:
  US11/353,742
• Publication Number:
  US 20060214927A1
• Time in Patent Office: 1,673 Days
• Field of Search: 348790-792, 348/558, 348/751, 348/766, 348511-512, 348/761, 348/521, 348/525, 348/441, 348/458, 348/739
• US Class Current: 348/739
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: G09G 5/399 using two or more bit-mapped memories, the operations of which are switched in time, e.g. ping-pong buffers

Abstract

In a display control apparatus which is supplied with an input synchronizing signal and an input video signal, and which generates display data from the input video signal on the basis of the input synchronizing signal, and supplies the display data to display means, when a change is detected in a cycle of the input synchronizing signal, the display means is supplied with display data of a frame prior to the occurrence of the change in the cycle, throughout a subsequent predetermined number of frame periods.

Claims

1. A display control apparatus which is supplied with an input synchronizing signal and an input video signal, and which generates display data on the basis of the input synchronizing signal from the input video signal, and supplies the display data to display means, comprising:

a video mode determination unit which determines a video mode on the basis of the input synchronizing signal;

a display data generation unit which generates display data from the input video signal;

a frame memory which stores the display data in correspondence to a frame; and

a memory control unit which controls writing and reading of the display data with respect to the frame memory,

wherein the memory control unit writes first display data generated from an input video signal of a first frame into the frame memory, reads the first display data from the frame memory in a second frame subsequent to the first frame, and supplies the first display data to the display means,

and wherein, when the video mode determination unit detects a change in a cycle of the input synchronizing signal during the second frame period, in response to the detection the memory control unit repeatedly supplies the first display data to the display means during a subsequent predetermined number of frame periods.

2. A display control apparatus which is supplied with an input synchronizing signal and an input video signal, and which generates display data on the basis of the input synchronizing signal from the input video signal, and supplies the display data to display means, comprising:

a video mode determination unit which determines a video mode on the basis of the input synchronizing signal;

a display data generation unit which generates display data from the input video signal;

a frame memory which stores the display data in correspondence to a frame; and

a memory control unit which controls writing and reading of the display data with respect to the frame memory,

wherein the memory control unit writes the display data of an input video signal of a present frame into a first frame memory region and a second frame memory region alternately, reads the display data of an input video signal of a previous frame alternately, and supplies the display data to the display means,

and wherein when the video mode determination unit detects a change in a cycle of the input synchronizing signal, in response to the detection the memory control unit repeatedly supplies, to the display means, in a subsequent predetermined number of frame periods, the display data written into the frame memory during a frame period prior to the detection of the change in the cycle.

3. The display control apparatus according to claim 2, wherein the memory control unit writes display data corresponding to an input video signal of each frame period into one of the frame memory regions in the subsequent number of frame periods, and reads, from the other frame memory region, the display data which is written into the frame memory during the frame period prior to the detection of the change in the cycle.

4. The display control apparatus according to claim 2, wherein after the predetermined number of frame periods, display data corresponding to the input video signal is supplied to the display means.

5. The display control apparatus according to claim 2, wherein, when detecting that a cycle of the input synchronizing signal is stabilized throughout a plurality of frames, subsequently, supply of display data of a frame prior to the generation of a change in the cycle to the display means is stopped, and then supply of display data corresponding to the input video signal to the display means is resumed.

6. The display control apparatus according to claim 2, wherein the display means is a plasma display panel, and the display data is data of a plurality of sub-frame with different display luminance, which are allocated during the frame period.

7. A display device, comprising:

a display control apparatus which is supplied with an input synchronizing signal and an input video signal, and generates display data on the basis of the input synchronizing signal from the input video signal; and

display means which is supplied with the display data from the display control apparatus and performs display on the basis of the display data, wherein

said display control apparatus comprises;

a video mode determination unit which determines a video mode on the basis of the input synchronizing signal;

a display data generation unit which generates display data from the input video signal;

a frame memory which stores the display data in correspondence to a frame; and

a memory control unit which controls writing and reading of the display data with respect to the frame memory,

the memory control unit writes the display data of an input video signal of a present frame into a first frame memory region and a second frame memory region alternately, reads the display data of an input video signal of a previous frame alternately, and supplies the display data to the display means, and

when the video mode determination unit detects a change in a cycle of the input synchronizing signal, in response to the detection the memory control unit repeatedly supplies, to the display means, in a subsequent predetermined number of frame periods, the display data written into the frame memory during a frame period prior to the detection of the change in the cycle.