LIQUID CRYSTAL DISPLAY DEVICE

Abstract

A liquid crystal display device includes liquid crystal pixels arrayed substantially in a matrix, a vertical driving circuit that selects the rows of pixels for video signal writing and for non-video signal writing, a horizontal driving circuit that writes a video signal in the pixels of a row selected for the video signal writing and a non-video signal in the pixels of a row selected for the non-video signal writing, and a control circuit that controls operation timings of the horizontal driving circuit and vertical driving circuit. In particular, the vertical driving circuit is configured to set a selection pattern for disabling an overlap between a selection period of selecting the pixels of each row for the video signal writing and a selection period of selecting the pixels of another row for the non-video signal writing, based on enable signals from the control circuit.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a diagram schematically showing the circuit configuration of a liquid crystal display device according to an embodiment of the present invention;

FIG. 2 is a diagram showing further details of the configuration of a vertical driving circuit shown in FIG. 1;

FIG. 3 is a diagram showing signal waveforms obtained in the operation of the liquid crystal display device shown in FIG. 1;

FIG. 4 is a diagram showing images displayed by the operation of the liquid crystal display device shown in FIG. 1;

FIG. 5 is a diagram showing signal waveforms obtained in a modification in which the waveforms of a vertical start pulse and vertical clock signal supplied from a controller to the vertical driving circuit shown in FIG. 2 are modified; and

FIG. 6 is an explanatory diagram that illustrates the conventional black insertion driving method.

Claims

1. A liquid crystal display device comprising: a plurality of liquid crystal pixels arrayed substantially in a matrix;a vertical driving circuit that selects the rows of liquid crystal pixels for video signal writing and for non-video signal writing;a horizontal driving circuit that writes a video signal in the liquid crystal pixels of a row selected for the video signal writing and a non-video signal in the liquid crystal pixels of a row selected for the non-video signal writing; anda control circuit that controls operation timings of the horizontal driving circuit and vertical driving circuit to perform the video signal writing for the liquid crystal pixels in units of one row in one vertical scanning period and to perform the non-video signal writing for the liquid crystal pixels in units of at least one row after the first video signal writing, with a delay of a time shorter than the vertical scanning period,wherein the vertical driving circuit is configured to set a selection pattern for disabling an overlap between a selection period of selecting the liquid crystal pixels of each row for the video signal writing and a selection period of selecting the liquid crystal pixels of another row for the non-video signal writing, based on a control signal from the control circuit.

2. The liquid crystal display device according to claim 1, wherein the liquid crystal pixels constitute a display panel together with a plurality of gate lines which are arranged along the rows of liquid crystal pixels and a plurality of pixel switching elements which are arranged near the liquid crystal pixels, and are turned on to allow that the horizontal driving circuit perform writing to the liquid crystal pixels of a selected row when the gate line corresponding to the liquid crystal pixels of the selected row is driven.

3. The liquid crystal display device according to claim 2, wherein the vertical driving circuit includes: a gate driver that receives first and second vertical start pulses supplied from the control circuit every vertical scanning period, starts selection of the rows of liquid crystal pixels for the video signal writing and selection of the rows of liquid crystal pixels for the black insertion writing, in response to the first and second vertical start signals, and outputs drive voltages to the gate lines which correspond to a selected row for the video signal writing and a selected row for the black insertion writing and are changed in sync with a vertical clock signal supplied from the control circuit; andan output switching unit that receives the drive voltages output from the gate driver for the video signal writing and for the black insertion writing, and switches the drive voltages upon change in the combination of at least two enable signals to output them in a time-division manner.

4. The liquid crystal display device according to claim 3, wherein the control circuit is configured to periodically thin out a pulse of the clock signal when the liquid crystal pixels are selected in units of two or more rows for the non-video signal writing by the control of the second start signal.

5. The liquid crystal display device according to claim 1, wherein the control signal from the control circuit includes at least two enable signals.

6. The liquid crystal display device according to claim 5, wherein the liquid crystal pixels constitute a display panel together with a plurality of gate lines which are arranged along the rows of liquid crystal pixels and a plurality of pixel switching elements which are arranged near the liquid crystal pixels, and are turned on to allow that the horizontal driving circuit perform writing to the liquid crystal pixels of a selected row when the gate line corresponding to the liquid crystal pixels of the selected row is driven.

7. The liquid crystal display device according to claim 6, wherein the vertical driving circuit includes: a gate driver that receives first and second vertical start pulses supplied from the control circuit every vertical scanning period, starts selection of the rows of liquid crystal pixels for the video signal writing and selection of the rows of liquid crystal pixels for the black insertion writing, in response to the first and second vertical start signals, and outputs drive voltages to the gate lines which correspond to a selected row for the video signal writing and a selected row for the black insertion writing and are changed in sync with a vertical clock signal supplied from the control circuit; andan output switching unit that receives the drive voltages output from the gate driver for the video signal writing and for the black insertion writing, and switches the drive voltages upon change in the combination of the at least two enable signals to output them in a time-division manner.

8. The liquid crystal display device according to claim 7, wherein the control circuit is configured to periodically thin out a pulse of the clock signal when the liquid crystal pixels are selected in units of two or more rows for the non-video signal writing by the control of the second start signal.