Liquid Crystal Driving Circuit and Liquid Crystal Display Device with the Same
It is an object to reduce the cost and the power consumption in a circuit part for generating a gradation voltage of a liquid crystal driving circuit. A gradation voltage generating circuit ( 78 ) is provided with a gradation voltage generating part ( 88 ) for generating a plurality of gradation voltage for gradation display by a pixel of a liquid crystal display part; a source-follower connected transistor group ( 90 ) for performing impedance conversion on each of the plurality of gradation voltages; and an analog switch part ( 94 ) for selecting an output of the transistor group ( 90 ) and applying the output to a pixel group of a liquid crystal display part. Furthermore, the transistor group ( 90 ) is preferably provided with a current control circuit part ( 92 ) for controlling a current that flows in each transistor.
1 . A liquid crystal driving circuit for a liquid crystal display device including a liquid crystal display part having a transistor for each individual pixel; a group of selection signal lines each provided for each row of the liquid crystal display part and connected to a gate electrode of the transistor for selecting a row of the liquid crystal display part; and a group of data electrode lines each provided for each column of the liquid crystal display part and connected to a source electrode of the transistor for supplying voltage data for controlling a display state of each pixel of the liquid crystal display part,
wherein a gradation voltage generating circuit is provided for generating a plurality of voltages for gradation display by the liquid crystal part, the gradation voltage generating circuit including a gradation voltage generating part for generating a plurality of gradation voltages for gradation display by the pixels of the liquid crystal display part, a source-follower connected transistor group for performing impedance conversion on each of the plurality of gradation voltages, and an analogue switch part for selecting an output of the transistor group and applying the output to the data electrode line group.
2 . The liquid crystal driving circuit according to claim 1 ,
wherein each transistor of the source-follower connected transistor group is provided with a current control circuit.
3 . The liquid crystal driving circuit according to claim 2 ,
wherein the current control circuit includes a resistor element.
4 . The liquid crystal driving circuit according to claim 2 ,
wherein the current control circuit includes at least a set of a resistor element and a switching element connected in series.
5 . The liquid crystal driving circuit according to claim 2 ,
wherein a current to be fed through the current control circuit is made variable.
6 . The liquid crystal driving circuit according to claim 5 ,
wherein the current to be fed through the current control circuit is set larger during a selection period to write data into the liquid crystal display device than during a non-selection period during which data writing into the liquid crystal display device is stopped.
7 . The liquid crystal driving circuit according to claim 1 ,
wherein said circuit is a circuit for driving the liquid crystal display device including a light source for sequentially and repeatedly emitting a plurality of color light and a liquid crystal display part for controlling transmission of the light emitted by the light source, in which one field is divided into a plurality of sub-fields, specific color light of the plurality of color light is emitted during at least a portion of period of the plurality of sub-fields, and an image corresponding to the specific color light is displayed on the liquid crystal display part to perform color display.
8 . A liquid crystal display device including a liquid crystal display part having a transistor for each individual pixel; a group of selection signal lines each provided for each row of the liquid crystal display part and connected to a gate electrode of the transistor for selecting a row of the liquid crystal display part; a group of data electrode lines each provided for each column of the liquid crystal display part and connected to a source electrode of the transistor for supplying voltage data for controlling a display state of each pixel of the liquid crystal display part; and a liquid crystal driving circuit for driving the liquid crystal display part,
wherein said liquid crystal driving circuit includes a gradation voltage generating circuit for generating a plurality of voltages for gradation display by the liquid crystal part,
the gradation voltage generating circuit having a gradation voltage generating part for generating a plurality of gradation voltages for gradation display by the pixels of the liquid crystal display part, a source-follower connected transistor group for performing impedance conversion on each of the plurality of gradation voltages, and an analogue switch part for selecting an output of the transistor group and applying the output to the data electrode line group.
9 . The liquid crystal driving circuit according to claim 2 ,
wherein said circuit is a circuit for driving the liquid crystal display device including a light source for sequentially and repeatedly emitting a plurality of color light and a liquid crystal display part for controlling transmission of the light emitted by the light source, in which one field is divided into a plurality of sub-fields, specific color light of the plurality of color light is emitted during at least a portion of period of the plurality of sub-fields, and an image corresponding to the specific color light is displayed on the liquid crystal display part to perform color display.
10 . The liquid crystal driving circuit according to claim 5 ,
wherein said circuit is a circuit for driving the liquid crystal display device including a light source for sequentially and repeatedly emitting a plurality of color light and a liquid crystal display part for controlling transmission of the light emitted by the light source, in which one field is divided into a plurality of sub-fields, specific color light of the plurality of color light is emitted during at least a portion of period of the plurality of sub-fields, and an image corresponding to the specific color light is displayed on the liquid crystal display part to perform color display.
11 . The liquid crystal driving circuit according to claim 6 ,
wherein said circuit is a circuit for driving the liquid crystal display device including a light source for sequentially and repeatedly emitting a plurality of color light and a liquid crystal display part for controlling transmission of the light emitted by the light source, in which one field is divided into a plurality of sub-fields, specific color light of the plurality of color light is emitted during at least a portion of period of the plurality of sub-fields, and an image corresponding to the specific color light is displayed on the liquid crystal display part to perform color display.
12 . The liquid crystal display device according to claim 8 ,
wherein each transistor of the source-follower connected transistor group is provided with a current control circuit.
13 . The liquid crystal display device according to claim 12 ,
wherein a current to be fed through the current control circuit is made variable.
14 . he liquid crystal display device according to claim 13 ,
wherein the current to be fed through the current control circuit is set larger during a selection period to write data into the liquid crystal display device than during a non-selection period during which data writing into the liquid crystal display device is stopped.
15 . The liquid crystal display device according to claim 8 ,
wherein said liquid crystal driving circuit is a circuit for driving the liquid crystal display device including a light source for sequentially and repeatedly emitting a plurality of color light and a liquid crystal display part for controlling transmission of the light emitted by the light source, in which one field is divided into a plurality of sub-fields, specific color light of the plurality of color light is emitted during at least a portion of period of the plurality of sub-fields, and an image corresponding to the specific color light is displayed on the liquid crystal display part to perform color display.