Display arrangement

• US 5,828,367 A
• Filed: 07/11/1994
• Issued: 10/27/1998
• Est. Priority Date: 10/21/1993
• Status: Expired due to Term

• Current Assignee: ROHM Co., Ltd.
• Original Assignee: ROHM Co., Ltd.
• Inventors: Kuga, Kaeko
• Primary Examiner(s): WU, XIAO MIN
• Application Number:
  US08/273,328
• Time in Patent Office: 1,569 Days
• Field of Search: 345/211, 345/212, 345/42, 345/52, 345/50, 345/213, 345/87, 345/98, 364/707
• US Class Current: 345/211
• CPC Class Codes: G06F 1/3218 of display devices
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A display arrangement includes a memory for storing image signals of one field supplied to an LCD display section, a comparator for determining whether the image signals of the next field to be supplied to the LCD display are those for a fixed image display or a changing image display by comparing those image signals with the image signals of the preceding field stored in the memory, and a controller for controlling a display driver so that, when the comparator determines that the image signals are for a fixed image display, the driver drives the LCD panel in a reduced-power drive mode. In one embodiment, the reduced-power drive mode is a spread-out mode and, in another embodiment, the reduced-power drive mode is a low-voltage mode.

Claims

1. A display arrangement comprising:

a display section for presenting visual images;

memory means for storing a set of image signals to be supplied to the display section;

input means for supplying successive sets of image signals to be stored in the memory means;

comparison circuit means for determining whether the set of image signals to be supplied to the display section are those for a constant image or for a changing image display by comparing a set of image signals to be supplied to the display section with a previous set of image signals read out of the memory means;

drive circuit means for driving the display device; and

control circuit means responsive to the comparison circuit means for controlling drive means so that, when the comparison circuit means determines that the image signals to be supplied to the display section are for a constant image display, the drive circuit means drives the display section in a reduced-power drive mode.

2. A display arrangement according to claim 1 wherein the reduced-power drive mode is a spread-out drive mode.

3. A display arrangement according to claim 1 including a power source for supplying power source voltage to the display section and wherein the reduced-power mode is a mode in which the power source voltage supplied to the display section is reduced to a level lower than the power source voltage supplied when a changing image is displayed.

4. A display arrangement according to claim 1 in which the display section comprises an LCD panel and the memory means comprises a nonvolatile memory.

5. A display arrangement according to claim 1 wherein the comparison circuit means determines the image signals to be for a constant image if more than 50% of the compared image signals coincide with each other.

6. A display arrangement comprising:

a display section for presenting visual images;

input means for supplying successive fields of signals to a memory means and to the display section;

memory means for storing image signals of a first field supplied to the display section;

comparison circuit means for determining whether the image signals of a second field subsequently supplied to the memory means and to the display section are those for a constant image display or for a changing image display by comparing the image signals of the second field with the image signals of the first field stored in the memory means;

drive circuit means for driving the display section; and

control circuit means responsive to the comparison circuit means for controlling the drive circuit means so that, when the comparison circuit means determines that the image signals supplied to the display section are those for a fixed image display, the drive circuit means drives the display section in a reduced-power drive mode.

7. A display arrangement according to claim 6 wherein the reduced-power drive mode is a spread-out drive mode.

8. A display arrangement according to claim 6 including a power source for supplying power source voltage to the display section and wherein the reduced-power mode is a mode in which the power source voltage supplied to the display section is reduced to a level lower than the power source voltage supplied when a changing image is displayed.

9. A display arrangement according to claim 6 in which the display section comprises an LCD panel and the memory means comprises a nonvolatile memory.

10. A display arrangement according to claim 6 wherein the comparison circuit means determines the image signals to be for a constant image if more than 50% of the compared image signals coincide with each other.