LIQUID CRYSTAL DISPLAY DEVICE

• US 20150325187A1
• Filed: 12/13/2013
• Published: 11/12/2015
• Est. Priority Date: 12/19/2012
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: MURATA, Mitsuhiro, JINDA, Akihito, IWATA, Yosuke, TANAKA, Kohhei
• Granted Patent: US 9,552,785 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/134381 Hybrid switching mode, i.e. for applying an electric field with components parallel and orthogonal to the substrates
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• CPC Class Codes: G09G 2300/0495 Use of transitions between isotropic and anisotropic phases in liquid crystals, by voltage controlled deformation of the liquid crystal molecules, as opposed to merely changing the orientation of the molecules as in, e.g. twisted-nematic [TN], vertical-aligned [VA], cholesteric, in-plane, or bi-refringent liquid crystals
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general

Abstract

Provided is a liquid crystal display device in which both a vertical electric field and a horizontal electric field are used and flickering is hardly recognized. The liquid crystal display device includes a liquid crystal panel and a control unit. The control unit includes a horizontal electric field control unit and a vertical electric field control unit. The horizontal electric field control unit controls the potentials of pairs of drive electrodes included in the liquid crystal panel, and thereby controls a horizontal electric field that is generated between each pair of drive electrodes. The vertical electric field control unit controls the potentials of a common electrode and an opposite electrode included in the liquid crystal panel, and thereby controls a vertical electric field that is generated between the common electrode and the opposite electrode. The horizontal electric field control unit controls the intensity and the polarity of the horizontal electric field when the vertical electric field control unit is causing the vertical electric field to be generated. The vertical electric field control unit inverts the polarity of the vertical electric field when the horizontal electric field control unit is maintaining the polarity of the horizontal electric field.

Claims

1. A liquid crystal display device, comprising:

a liquid crystal panel that has a display region in which a plurality of pixels are arranged; and

a control unit that causes an image to be displayed in said display region,

wherein said liquid crystal panel includes;

an active matrix substrate;

an opposite substrate facing said active matrix substrate; and

a liquid crystal layer sealed between said active matrix substrate and said opposite substrate,

wherein said active matrix substrate includes;

a pair of drive electrodes in each pixel; and

a common electrode arranged further away from said liquid crystal layer than said pair of drive electrodes in each pixel,

wherein said opposite substrate includes an opposite electrode facing said common electrode and said pair of drive electrodes in each pixel,

wherein said control unit includes;

a horizontal electric field control unit that controls potentials of said pair of drive electrodes in each pixel to control a horizontal electric field that is generated between each of said pair of drive electrodes in each pixel, and

a vertical electric field control unit that controls potentials of said common electrode and said opposite electrode to control a vertical electric field that is generated between said common electrode and said opposite electrode,

wherein, when said vertical electric field control unit is causing said vertical electric field to be generated, said horizontal electric field control unit controls an intensity and a polarity of said horizontal electric field, and

wherein, when said horizontal electric field control unit is maintaining the polarity of said horizontal electric field, said vertical electric field control unit inverts a polarity of said vertical electric field.

2. The liquid crystal display device according to claim 1, wherein, when the polarity of the horizontal electric field is being maintained, the vertical electric field control unit causes a length of a period in which the polarity of the vertical electric field is positive to be the same as a length of a period in which the polarity of said vertical electric field is negative.

3. The liquid crystal display device according to claim 1, wherein said vertical electric field control unit causes a potential of said opposite electrode to change to invert the polarity of said vertical electric field.

4. The liquid crystal display device according to claim 3,

wherein said opposite electrode includes a plurality of segmented electrodes, and

wherein said vertical electric field control unit causes a potential of each of the segmented electrodes to change sequentially.

5. The liquid crystal display device according to claim 1, wherein said vertical electric field control unit causes the potential of said common electrode to change to invert the polarity of said vertical electric field.

6. The liquid crystal display device according to claim 5,

wherein said common electrode includes a plurality of segmented electrodes, and

wherein said vertical electric field control unit causes a potential of each of the segmented electrodes to change sequentially.

7. The liquid crystal display device according to claim 1, wherein a direction in which the polarity of said vertical electric field is inverted when said horizontal electric field is maintained with a positive polarity is the same as a direction in which the polarity of said vertical electric field is inverted when said horizontal electric field is maintained with a negative polarity.

8. The liquid crystal display device according to claim 1, wherein said opposite substrate further comprises a dielectric layer arranged closer to said liquid crystal layer than said opposite electrode.

9. The liquid crystal display device according to claim 1, wherein said horizontal electric field control unit controls the potentials of said pair of drive electrodes in each pixel with respect to all of said pixels in a period that is shorter than one frame.

10. The liquid crystal display device according to claim 1, wherein, said vertical electric field control unit inverts the polarity of said vertical electric field within each vertical scanning period of the image to be displayed, which constitutes a frame of the image, and said horizontal electric field control unit inverts the polarity of said horizontal electric field for every such vertical scanning period.