Liquid crystal display device for improving coloration between privacy and public modes
A liquid crystal display device comprises a liquid crystal panel and a control unit configured to drive the liquid crystal panel, wherein the liquid crystal panel includes a first substrate, a liquid crystal layer, and a second substrate, all of which are provided in a stated order, the first substrate includes a first electrode and a second electrode either stacked via a first insulating layer or disposed opposite each other, the second substrate includes a third electrode, the control unit includes a display mode switching unit, a gamma correction table memory unit, a gamma correction unit, and an image data output unit, the display mode switching unit switches between narrow viewing angle mode and wide viewing angle mode by controlling a voltage applied to the third electrode, the gamma correction table memory unit contains gamma correction tables by each of which a gray level is associated with an application voltage to the first electrode and/or the second electrode, the gamma correction unit acquires different gamma correction tables from the gamma correction table memory unit for the narrow viewing angle mode and for the wide viewing angle mode, performs gamma correction on original image data based on each of the gamma correction tables, and outputs resultant gamma-corrected image data to the image data output unit, and the image data output unit outputs a liquid crystal panel drive signal to the liquid crystal panel and adjusts the application voltage to the first electrode and/or the second electrode.
1 . A liquid crystal display device comprising:
a liquid crystal panel; and
a control unit configured to drive the liquid crystal panel,
wherein the liquid crystal panel includes a first substrate, a liquid crystal layer, and a second substrate, all of which are provided in this stated order,
the first substrate includes a first electrode and a second electrode either stacked via a first insulating layer or disposed opposite each other,
the second substrate includes a third electrode,
the control unit includes a display mode switching unit, a gamma correction table memory unit, a gamma correction unit, and an image data output unit,
the display mode switching unit switches between a narrow viewing angle mode and a wide viewing angle mode by controlling a voltage applied to the third electrode,
the gamma correction table memory unit contains gamma correction tables through each of which a gray level is associated with an application voltage to the first electrode and/or the second electrode, the gamma correction unit acquires different gamma correction tables from the gamma correction table memory unit for the narrow viewing angle mode and for the wide viewing angle mode, performs a gamma correction on original image data based on each of the acquired gamma correction tables, and outputs resultant gamma-corrected image data to the image data output unit,
the image data output unit outputs a liquid crystal panel drive signal to the liquid crystal panel and adjusts the application voltage to the first electrode and/or the second electrode,
a first gamma correction table, among the gamma correction tables, is used in the wide viewing angle mode and contains a gamma value that is constant between gray levels 0 to 255,
a second gamma correction table, among the gamma correction tables, is used in the narrow viewing angle mode and contains a gamma value that has a plurality of values between the gray levels 0 to 255, and
having X as an arbitrary gray level between the gray levels 0 to 255 both exclusive,
the gamma value in the second gamma correction table is smaller than the gamma value in the first gamma correction table at gray levels from 0 inclusive to X exclusive, and
the gamma value in the second gamma correction table is greater than the gamma value in the first gamma correction table at gray levels from X to 255 both inclusive.
2 . The liquid crystal display device according to claim 1 , wherein
the second gamma correction table contains a first gamma value, and
the first gamma correction table contains a second gamma value,
the first gamma value is different from the second gamma value by less than or equal to 0.4.
3 . The liquid crystal display device according to claim 1 , wherein
at least one of the first electrode and the second electrode is provided in each picture element and includes a linear electrode section extending in a first direction, and
the third electrode includes a linear electrode section extending in a second direction that intersects with the first direction in a plan view.
4 . A liquid crystal display device comprising:
a liquid crystal panel; and
a control unit configured to drive the liquid crystal panel, wherein
the liquid crystal panel includes a first substrate, a liquid crystal layer, and a second substrate, all of which are provided in this stated order,
the first substrate includes a first electrode and a second electrode either stacked via a first insulating layer or disposed opposite each other,
the second substrate includes a third electrode,
the control unit includes a display mode switching unit, a gamma correction table memory unit, a gamma correction unit, and an image data output unit,
the display mode switching unit switches between a narrow viewing angle mode and a wide viewing angle mode by controlling a voltage applied to the third electrode,
the gamma correction table memory unit contains gamma correction tables through each of which a gray level is associated with an application voltage to the first electrode and/or the second electrode,
the gamma correction unit acquires different gamma correction tables from the gamma correction table memory unit for the narrow viewing angle mode and for the wide viewing angle mode, performs a gamma correction on original image data based on each of the acquired gamma correction tables, and outputs resultant gamma-corrected image data to the image data output unit,
the image data output unit outputs a liquid crystal panel drive signal to the liquid crystal panel and adjusts the application voltage to the first electrode and/or the second electrode,
a first gamma correction table, among the gamma correction tables, is used in the wide viewing angle mode and contains a gamma value that is constant between gray levels 0 to 255,
a second gamma correction table, among the gamma correction tables, is used in the narrow viewing angle mode and contains a gamma value that has a plurality of values between the gray levels 0 to 255, and
having X as an arbitrary gray level from the gray levels 0 to 255 both exclusive, and Y as an arbitrary gray level higher than X,
the gamma value in the second gamma correction table is smaller than the gamma value in the first gamma correction table at gray levels from 0 inclusive to X exclusive, and
the gamma value in the second gamma correction table is greater than the gamma value in the first gamma correction table at gray levels from Y to 255 both inclusive.