Liquid crystal display, LCD driver, and operating method of LCD driver

1 . A liquid crystal display apparatus comprising:

a liquid crystal display (LCD) panel; and

an LCD driver,

wherein said LCD driver comprises:

a first memory having a capacity more than a capacity of image data for one frame and configured to receive the image data externally to store therein;

a second memory;

an overdrive processing circuit configured to compress the image data read out from said first memory to generate a compressed image data, write the generated compressed image data in said second memory, and perform an overdrive process based on the image data of a current frame read out from said first memory and the compressed image data of a previous read out from said second memory to generate a post-process image data; and

a data line driving section configured to drive data lines of said LCD panel in response to the post-process image data.

2 . The liquid crystal display apparatus according to claim 1 , wherein said overdrive processing circuit reads the image data from said first memory for every two or more pixels.

3 . The liquid crystal display apparatus according to claim 2 , wherein said overdrive processing circuit comprises:

a parallel/serial converting circuit configured to perform a parallel/serial converting process on the current frame image data read out from said first memory to output the image data for every pixel; and

a post-process image data generating section configured to calculate the post-process image data based on the current frame image data outputted from said parallel/serial converting circuit and the previous frame compressed image data read out from said second memory.

4 . The liquid crystal display apparatus according to claim 2 , wherein said overdrive processing circuit performs a write operation and a read operation of the compressed image data to said second memory every two or more pixels.

5 . The liquid crystal display apparatus according to claim 4 , wherein each of the two or more pixels contains an R display dot for a red display, a G display dot for a green display and a B display dot for a blue display,

each image data contains an R data indicating a gradation of the R display dot, a G data indicating a gradation of the G display dot, and a B data indicating a gradation of the B display dot, and

each of the compressed image data contains an R average data calculated by extracting upper bits from an average of the R data of the two or more pixels, a G average data calculated by extracting upper bits from an average of the G data of the two or more pixels, and a B average data calculated by extracting upper bits from an average of the B data of the two or more pixels.

6 . The liquid crystal display apparatus according to claim 1 , wherein said LCD panel has a plurality of pixels, each of which contains an R display dot for a red display, a G display dot for a green display and a B display dot for a blue display,

each image data contains an R data indicating a gradation of the R display dot, a G data indicating a gradation of the G display dot, and a B data indicating a gradation of the B display dot, and

in the generation of the compressed image data, compression ratios of the R data and the B data are higher than a compression ratio of the G data.

7 . The liquid crystal display apparatus according to claim 1 , wherein said overdrive processing circuit comprises:

a compression processing circuit configured to compress the current frame image data read out from said first memory to generate the compressed image data;

an overdrive image data generating circuit configured to perform the overdrive process on the current frame image data read out from said first memory based on the previous frame compressed image data read our from said second memory to generate an overdrive image data;

a video/still image determining circuit configured to compare the current frame compressed image data received from said compressed processing circuit and the precious frame compressed image data read from said second memory; and

a selector configured to select as the post-process image data, one of the current frame image data read from said first memory and the overdrive image data in response to an output from said video/still image determining circuit.

8 . A liquid crystal display (LCD) driver comprising:

a first memory configured to receive the image data externally to store therein;

a second memory;

an overdrive processing circuit configured to compress the image data read out from said first memory to generate a compressed image data, write the generated compressed image data in said second memory, and perform an overdrive process based on the image data of a current frame read out from said first memory and the compressed image data of a previous read out from said second memory to generate a post-process image data; and

a data line driving section configured to drive data lines of an LCD panel in response to the post-process image data.

9 . The LCD driver according to claim 8 , wherein said overdrive processing circuit reads the image data from said first memory for every two or more pixels.

10 . The LCD driver according to claim 9 , wherein said overdrive processing circuit comprises:

a parallel/serial converting circuit configured to perform a parallel/serial converting process on the current frame image data read out from said first memory to output the image data for every pixel; and

a post-process image data generating section configured to calculate the post-process image data based on the current frame image data outputted from said parallel/serial converting circuit and the previous frame compressed image data read out from said second memory.

11 . The LCD driver according to claim 9 , wherein said overdrive processing circuit performs a write operation and a read operation of the compressed image data to said second memory every two or more pixels.

12 . The LCD driver according to claim 11 , wherein each of the two or more pixels contains an R display dot for a red display, a G display dot for a green display and a B display dot for a blue display,

each image data contains an R data indicating a gradation of the R display dot, a G data indicating a gradation of the G display dot, and a B data indicating a gradation of the B display dot, and

each of the compressed image data contains an R average data calculated by extracting upper bits from an average of the R data of the two or more pixels, a G average data calculated by extracting upper bits from an average of the G data of the two or more pixels, and a B average data calculated by extracting upper bits from an average of the B data of the two or more pixels.

13 . The LCD driver according to claim 8 , wherein said LCD panel has a plurality of pixels, each of which contains an R display dot for a red display, a G display dot for a green display and a B display dot for a blue display,

each image data contains an R data indicating a gradation of the R display dot, a G data indicating a gradation of the G display dot, and a B data indicating a gradation of the B display dot, and

in the generation of the compressed image data, compression ratios of the R data and the B data are higher than a compression ratio of the G data.

14 . The LCD driver according to claim 8 , wherein said overdrive processing circuit comprises:

a compression processing circuit configured to compress the current frame image data read out from said first memory to generate the compressed image data;

an overdrive image data generating circuit configured to perform the overdrive process on the current frame image data read out from said first memory based on the previous frame compressed image data read our from said second memory to generate an overdrive image data;

a video/still image determining circuit configured to compare the current frame compressed image data received from said compressed processing circuit and the precious frame compressed image data read from said second memory; and

a selector configured to select as the post-process image data, one of the current frame image data read from said first memory and the overdrive image data in response to an output from said video/still image determining circuit.

15 . An operation method of an LCD driver, comprising:

receiving an image data externally to store in a first memory of said LCD driver;

compressing said image data read from said first memory to generate a compressed image data;

writing the generated compressed image data in a second memory of said LCD driver;

performing an overdrive process based on the image data of a current frame read from said first memory and the compressed image data of a previous frame read from said second memory, to generate a post-process image data; and

driving data lines of a LCD panel in response to the post-process image data.