Patent ID: 8009180

Claim:
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 wherein said correction data comprises correction point data CP 0 to CP 5 , if said input gradation data is D IN , said output gradation data is D OUT and an intermediate data value D IN Center is defined by a following equation (1) by using a permissible maximum value D IN MAX of said input gradation data: D IN Center =D IN MAX /2 (1) (1) when said correction point data CP 0 to CP 5 are determined for said input gradation data D IN to be smaller than said intermediate data value D IN Center and for a gamma value of said gamma correction to be less than one, said output gradation data D OUT is calculated from the following equation (2a): D OUT =2( CP 1 −CP 0) PD INS /K 2 +( CP 3 −CP 0) D INS /K+CP 0 (2a) (2) said correction point data CP 0 to CP 5 are determined for said input gradation data D IN smaller than said intermediate data value D IN Center and for a gamma value of said gamma correction to exceed one, said output gradation data D OUT is calculated from the following equation (2b): D OUT =2( CP 1 −CP 0) ND INS /K 2 +( CP 3 −CP 0) D INS /K+CP 0 (2b) (3) when said input gradation data D IN is larger than said intermediate data value D IN Center , said output gradation D OUT is calculated from the following equation (2c): D OUT =2( CP 4 −CP 2) ND INS /K 2 +( CP 5 −CP 2) D INS /K+CP 2 (2c) where when a parameter R is defined by the following equation: R=K 1/2 ·D INS 1/2 , said K, D INS , PD INS , and ND INS take values defined by the following equations: K =( D IN MAX +1)/2, D INS =D IN (in case of D IN <D IN Center ) D INS =D IN +1 −K (in case of D IN >D IN Center ) PD INS =( K−R )· R ND INS =( K−D INS )· D INS .