Display device with adaptive selection of the number of simultaneously displayed rows

• US 20020135551A1
• Filed: 11/29/2001
• Published: 09/26/2002
• Est. Priority Date: 11/30/2000
• Status: Active Grant

• Current Assignee: Dynamic Data Technologies LLC
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Duisters, Anthonius Franciscus, Zeiter, Dominik
• Granted Patent: US 6,882,332 B2
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G09G 2310/0208 using active addressing
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2330/022 in absence of operation, e.g. no data being entered during a predetermined time
• CPC Class Codes: G09G 3/3625 using active addressing
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers

Abstract

The invention relates to a display device which includes a driver circuit and a liquid crystal display with a plurality of rows R and columns C. The invention also relates to a driver circuit for driving a display. In order to reduce the power consumption of display devices, displays are operated in the partial display mode. According to the MRA (Multiple Row Addressing) technique a plurality of rows p is driven simultaneously. The number of rows p to be simultaneously driven, however, differs for displays of different size. When a display is operated in the partial display mode, therefore, for an optimum optical performance it is necessary that the value p of the rows to be simultaneously driven is other than this number in full size operation. In order to drive the rows R and columns C, at least p+1 voltages are required when F=G_MAX. Because the number of simultaneously driven rows is reduced upon a transition from the full size mode of operation to the partial display mode, it is also no longer necessary to generate as many voltages as would be required for operation in the full size mode. Therefore, upon transition to the partial display mode the voltage driver stages that are no longer required are switched off by way of a switching device. As a result, displays of different size can also be driven by means of one driver circuit.

Claims

1. A display device which includes a driver circuit (1) and a display (2) with a plurality of rows R and columns C, where a number p indicates the number of simultaneously driven rows, where the rows R and the columns C can be driven by means of voltage values of the equally high voltages F and G_MAX, and where the display has a multiplexibility of m≧

R and the number p of simultaneously driven rows can be selected in dependence on the display size to be driven, whereas the driver circuit (1) includes voltage driver stages (buffers) that can be switched off in dependence on the optimal number p to be simultaneously driven, which is derived from the display size.

2. A display device as claimed in claim 1, characterized in that the optimum number p of rows to be simultaneously driven is derived from the display size to be driven during a partial display mode or from a sub-region of the display.

3. A display device as claimed in claim 1, characterized in that a sequence for the supply of the image data to be displayed from a memory (9) is the same for all values p.

4. A display device as claimed in claim 1, characterized in that the simultaneously driven rows p can be subdivided into p_max/p sub-regions for an optimum value p that is smaller than the maximum value p_max.

5. A driver circuit which includes a plurality of voltage driver stages for generating a plurality of partial voltage values in order to drive a display with rows R and columns C, where voltage driver stages can be selected and switched off in dependence on the display size and on an optimum number p of simultaneously driven rows that is dependent thereon.