Display apparatus containing controller driver with correcting circuit and method of driving display panel

A controller driver comprising:

• a correcting circuit configured to carry out gamma correction on input gradation data in response to correction data which specifies a shape of a gamma curve;
• a correction data storage section configured to receive said correction data from outside said controller driver to store therein the received correction data, and to transfer the stored correction data to said correcting circuit;
• and
• a driving circuit configured to drive a display panel in response to output gradation data which is outputted from said correcting circuit,
• wherein said correcting circuit:
• selects a correction calculation equation from among a plurality of correction calculation equations based on a value of said input gradation data and said correction data, the selected correction calculation equation including a parameter which is determined based on a maximum value of the input gradation data, and a coefficient which is determined based on said correction data;
• and
• uses said input gradation data as a variable and carries out approximation calculation of said gamma correction by using the selected correction calculation equation;
• and
• wherein said correction data comprises correction point data CP0 to CP5,
• if said input gradation data is DIN, said output gradation data is DOUT and an intermediate data value DINCenter is defined by a following equation (1) by using a permissible maximum value DINMAX of said input gradation data:
• DINCenter=DINMAX/2 (1)
• (1) when said correction point data CP0 to CP5 are determined for said input gradation data DIN to be smaller than said intermediate data value DINCenter and for a gamma value of said gamma correction to be less than one, said output gradation data DOUT is calculated froth the following equation (2a):
• DOUT=2(CP1−CP0)PDINS/K2+(CP3−CP0)DINS/K+CP0 (2a)
• (2) when said correction point data CP0 to CP5 are determined for said input gradation data DIN to be smaller than said intermediate data value DINCenter and for a gamma value of said gamma correction to exceed one, said output gradation data DOUT is calculated from the following equation (2b):
• DOUT=2(CP1−CP0)NDINS/K2+(CP3−CP0)DINS/K+CP0 (2b)
• (3) when said input gradation data DIN is larger than said intermediate data value DINCenter, said output gradation data DOUT is calculated from the following equation (2c):
• DOUT=2(CP4−CP2)NDINS/K+CP2 (2c)
• where when a parameter R is defined by the following equation:
• R=K1/2·DINS1/2,
• said K, DINS, PDINS, and NDINS take values defined by the following equations:
• K=(DINMAX+1)/2,
• DINS=DIN (in case of DIN<DINCenter)
• DINS=DIN+1−K (in case of DIN>DINCenter)
• PDINS=(K·R)·R
• NDINS=(K−DINS)·DINS.

A method of driving a display panel, comprising:

• generating output gradation data from input gradation data by:
• selecting a correction calculation equation from among a plurality of correction calculation equations based on a value of said input gradation data and a value of correction, data which specifies a shape of a gamma curve, the selected correction calculation equation including a parameter which is determined based on a maximum value of the input gradation data, and a coefficient which is determined based on the correction data;
• and
• carrying out an approximation of gamma correction on the input gradation data by using the selected correction calculation equation;
• and
• driving a display panel in response to said output gradation data;
• and
• wherein said correction data comprises correction point data CP0 to CP5,
• if said input gradation data is DIN, said output gradation data is DOUT and an intermediate data value DINCenter is defined by a following equation (1) by using a permissible maximum value DINMAX of said input gradation data:
• DINCenter=DINMAX/2 (1)
• (1) when said correction point data CP0 to CP5 are determined for said input gradation data DIN to be smaller than said intermediate data value DINCenter and for a gamma value of said gamma correction to be less than one, said output gradation data DOUT is calculated from the following equation (2a):
• DOUT=2(CP1−CP0)PDINS/K2+(CP3−CP0)DINS/K+CP0 (2a)
• (2) when said correction point data CP0 to CP5 are determined for said input gradation data DIN to be smaller than said intermediate data value DINCenter and for a gamma value of said gamma correction to exceed one, said output gradation data DOUT is calculated from the following equation (2b):
• DOUT=2(CP1−CP0)NDINS/K2+(CP3−CP0)DINS/K+CP0 (2b)
• (3) when said input gradation data DIN is larger than said intermediate data value DINCenter, said output gradation data DOUT is calculated from the following equation (2c):
• DOUT=2(CP4−CP2)NDINS/K2+(CP5−CP2)DINS/K+CP2 (2c)
• where when a parameter R is defined by the following equation:
• R=K1/2·DINS1/2,
• said K, DINS, PDINS, and NDINS take values defined by the following equations:
• K=(DINMAX+1)/2
• DINS=DIN (in case of DIN<DINCenter)
• DINS=DIN+1−K (in case of DIN>DINCenter)
• PDINS=(K−R)·R
• NDINS=(K−DINS)·DINS.

A display apparatus comprising:

• a display panel;
• a correcting circuit configured to carry out a gamma correction on input gradation data in response to correction data which specifies a shape of a gamma curve to generate output gradation data;
• a correction data storage section configured to receive and store said correction data, supplied externally, and to transfer the stored correction data to said correcting circuit;
• and
• a driving circuit configured to drive said display panel in response to said output gradation data from said correcting circuit,
• wherein said correcting circuit:
• selects a correction calculation equation from among a plurality of correction calculation equations based on a value of said input gradation data and said correction data, the selected correction calculation equation including a parameter which is determined based on a maximum value of the input gradation data, and a coefficient which is determined based on said correction data;
• and
• carries out an approximation, calculation for said gamma correction based on said input gradation data by using the selected correction calculation equation;
• and
• said correction calculation equation is of a form:
• D
• OUT
• =
• B
• ·
• D
• IN
• sel
• (
• K
• 2
• /
• 2
• )
• +
• C
• ·
• D
• INS
• K
• +
• A
• ,
• wherein:
• DOUT represents output gradation data,
• DIN represents input gradation data,
• DINMAX represents a maximum value of DIN,
• K=(DINMAX+1)/2,
• DINS=DIN if a most significant bit of DIN is 0,
• DINS=DIN+1−K if a most significant bit of DIN is 1, and
• values of A, B, C, and DINse1 are determined according to said input gradation data and said correction data.