Signal drive circuit, display device, electro-optical device, and signal drive method
A signal drive circuit for an active matrix type liquid crystal panel. This signal drive circuit comprises: a shift register for shifting image data sequentially on a block basis, each block constituting a plurality of signal lines, to correspond to signal lines of a block; a line latch for latching the image data in synchronization with a horizontal synchronizing signal; a drive voltage generation circuit for generating drive voltages based on the image data; and a signal line drive circuit. This signal driver controls a partial display based on the partial display data which is designated on a block basis. Each of the signal lines in a block set as a display area is driven based on the image data. Each of the signal lines in a block set as a non-display area is driven by a predetermined non-display level voltage generated by a non-display level voltage supply circuit.
1. A signal drive circuit for driving a plurality of signal lines of an electro-optical device which includes a plurality of pixels defined by a plurality of scan lines and the signal lines crossing each other, based on image data comprising:
a line latch for latching the image data for a horizontal scan period;
a drive voltage generating section for generating drive voltages of the signal lines based on the image data latched by the line latch;
a signal line drive section for driving the signal lines based on the drive voltages generated by the drive voltage generating section; and
a partial display data holding section for holding partial display data which indicates propriety of output of the drive voltages to the signal lines on a block basis, each block constituting a predetermined number of signal lines,
wherein the signal line drive section includes:
an impedance conversion section for subjecting drive voltages generated by the drive voltage generating section to impedance conversion to output the impedance-converted drive voltages to the signal lines; and
a non-display level voltage supplying section for generating predetermined non-display level voltages on the signal lines, and
wherein each of the signal lines is driven by one of the impedance conversion section and the non-display level voltage supplying section on a block basis based on the partial display data.
2. The signal drive circuit according to claim 1 , further comprising:
a shift register for shifting the sequentially supplied image data to supply the image data to the line latch per horizontal scan unit;
a shift direction switching section for switching shift direction of the shift register based on a predetermined shift direction switching signal; and
a data interchange section for interchanging order of the partial display data which is held in the partial display data holding section on a block basis, based on the predetermined shift direction switching signal,
wherein the signal line drive section controls the output of the drive voltages of the signal lines on a block basis based on the partial display data supplied from the data interchange section.
3. The signal drive circuit according to claim 1 ,
wherein the impedance conversion section subjects drive voltages to impedance conversion, outputs the impedance-converted drive voltages to signal lines of a block when the block is set to a display area due to the partial display data and sets an output thereof to a high impedance state when the block is set to a non-display area due to the partial display data, and
wherein the non-display level voltage supplying section sets an output thereof to a high impedance state when the block is set to a display area due to the partial display data and supplies predetermined non-display level voltages to signal lines of a block when the block is set to a non-display area due to the partial display data.
4. The signal drive circuit according to claim 1 ,
wherein the drive voltage generating section interrupts generation of drive voltages for driving signal lines of a block in which output of the drive voltage generating section is turned OFF due to the partial display data.
5. The signal drive circuit according to claim 1 ,
wherein the electro-optical device includes pixel electrodes corresponding to the respective pixels provided via switching sections connecting the scan lines and the signal lines, and
wherein the non-display level voltage sets a voltage difference between voltages applied to the pixel electrodes and voltages of counter electrodes opposite to the pixel electrodes via electro-optical elements lower than a predetermined threshold value.
6. The signal drive circuit according to claim 1 ,
wherein the electro-optical device includes pixel electrodes corresponding to the respective pixels provided via switching sections connecting the scan lines and the signal lines, and
wherein the non-display level voltage is substantially equal to voltages on counter electrodes opposite to the pixel electrodes via electro-optical elements.
7. The signal drive circuit according to claim 1 ,
wherein the non-display level voltage is one of maximum and minimum gradation voltages which is generated based on the image data.
8. The signal drive circuit according to claim 1 ,
wherein each block corresponds to eight pixels.
9. A display device comprising:
a display panel including a plurality of pixels defined by a plurality of scan lines and a plurality of signal lines crossing each other;
a scan drive circuit for scanning and driving the scan lines; and
a signal drive circuit for driving the signal lines based on image data,
wherein the signal drive circuit includes:
a line latch for latching the image data for a horizontal scan period;
a drive voltage generating section for generating drive voltages of the signal lines based on the image data latched by the line latch;
a signal line drive section for driving the signal lines based on the drive voltages generated by the drive voltage generating section; and
a partial display data holding section for holding partial display data which indicates propriety of output of the drive voltages to the signal lines on a block basis, each block constituting a predetermined number of signal lines, and
wherein the signal line drive section includes:
an impedance conversion section for subjecting drive voltages generated by the drive voltage generating section to impedance conversion to output the impedance-converted drive voltages to the signal lines; and
a non-display level voltage supplying section for generating predetermined non-display level voltages on the signal lines, and
wherein each of the signal lines is driven by one of the impedance conversion section and the non-display level voltage supplying section on a block basis based on the partial display data.
10. An electro-optical device comprising:
a plurality of pixels defined by a plurality of scan lines and a plurality of signal lines crossing each other;
a scan drive circuit for scanning and driving the scan lines; and
a signal drive circuit for driving the signal lines based on image data,
wherein the signal drive circuit includes:
a line latch for latching the image data for a horizontal scan period;
a drive voltage generating section for generating drive voltages of the signal lines based on the image data latched by the line latch;
a signal line drive section for driving the signal lines based on the drive voltages generated by the drive voltage generating section; and
a partial display data holding section for holding partial display data which indicates propriety of output of the drive voltages to the signal lines on a block basis, each block constituting a predetermined number of signal lines, and
wherein the signal line drive section includes:
an impedance conversion section for subjecting drive voltages generated by the drive voltage generating section to impedance conversion to output the impedance-converted drive voltages to the signal lines; and
a non-display level voltage supplying section for generating predetermined non-display level voltages on the signal lines, and
wherein each of the signal lines is driven by one of the impedance conversion section and the non-display level voltage supplying section on a block basis based on the partial display data.
11. A signal drive method for a signal drive circuit driving a plurality of signal lines of an electro-optical device including pixels which are defined by a plurality of scan lines and the signal lines crossing each other, comprising the steps of:
latching the image data for a horizontal scan period;
generating drive voltages for each of the signal lines based on the latched image data;
holding partial display data which indicates propriety of output of the drive voltages to the signal lines on a block basis, each block constituting a predetermined number of signal lines;
subjecting drive voltages generated by the drive voltage generating section to impedance conversion to output the impedance-converted drive voltages to the signal lines on a block basis, when one of the blocks is set to a display area based on the partial display data; and
outputting non-display level voltages from a non-display level voltage supplying section to the signal lines on a block basis, when one of the blocks is set to a non-display area based on the partial display data.