Display device, and large-sized display apparatus employing the same

A non-self-luminous display device comprising:

• an image signal level detection unit which detects whether or not a displayed image includes an image in a lower tone region lower than a predetermined tone;
• and
• a γ conversion unit which performs an offset process for changing, by a predetermined amount, the brightness of respective tones in said lower tone region, when said displayed image includes an image in said lower tone region.

A non-self-luminous display device comprising:

• an image movement detection unit which determines whether said displayed image is a moving image or a still image;
• and
• a backlight control unit which reduces the brightness of backlight to below a predetermined brightness, when said image movement detection unit detects a still image for a predetermined time.

A non-self-luminous display device comprising:

• an image signal level detection unit which determines whether or not a displayed image includes a boundary region having a tone difference equal to or greater than a predetermined tone difference;
• and
• a band variable filter unit which changes, in a stepwise manner, the tone difference at said boundary region detected by said image signal level detection unit to below said predetermined tone difference.

A non-self-luminous display device comprising:

• a γ conversion unit which can optionally change the number of tones of a displayed image, wherein
• said γ conversion unit changes the number of tones of said displayed image including an afterimage resulted from displaying said displayed image which is a still image for a long time.