JP5017683B2 - Display driving device and display device including the same - Google Patents

Description

  The present invention relates to a display driving device that drives display pixels by outputting gradation voltages based on display data, and a display device that includes the display driving device and drives a display panel to display an image.

  As a dot matrix type display panel used in a liquid crystal display device, a simple matrix type display panel and an active matrix type display panel are known. Among them, in an active matrix display panel, a plurality of scanning lines and a plurality of signal lines are arranged on the display panel so as to be orthogonal to each other, and a thin film transistor (Thin Film) is formed in the vicinity of the intersection of the scanning lines and the signal lines. A display pixel is configured by disposing a pixel electrode via a transistor (hereinafter referred to as TFT) and filling a liquid crystal with a common electrode disposed opposite to the pixel electrode. In the display driving device for driving the display panel, a voltage is applied between the pixel electrode and the common electrode, thereby changing the magnitude of the electric field applied to the liquid crystal layer filled between the pixel electrode and the common electrode. It is driven to change the alignment state.

As a method for performing gradation display according to display data in a liquid crystal display device, there is a voltage gradation method. The voltage gradation method is a method of performing gradation display by applying a gradation voltage corresponding to the gradation of display data to a signal line. As an example of applying such a voltage gradation method, for example, Patent Literature 1 or the like, a predetermined reference voltage is divided by a plurality of resistors to generate a plurality of gradation voltages corresponding to the number of gradations of display data, and the generated plurality of gradation voltages are supplied to the DAC to generate a digital signal. The gray scale voltage corresponding to the gray scale of the display data supplied in (1) is selected by the DAC and supplied to the display panel. Further, in Patent Document 1, in order to generate a grayscale voltage as soon as possible, the target grayscale voltage can be generated quickly, and the grayscale voltage can be stably supplied to the display panel. An impedance conversion amplifier circuit (gradation amplifier) is provided between the gradation voltage generation circuit and the DAC.
JP 2006-39205 A

  Conventionally, the driving capability of each gradation amplifier is fixed regardless of the level of the gradation voltage output. However, in the intermediate gradation region, the change in the gradation voltage with respect to the change in the gradation value indicated by the display data is larger than that in the high gradation region and the low gradation region. Here, when the drive capability of each gradation amplifier is set to be relatively small in order to suppress the power consumption in the gradation amplifier section, the gradation voltage applied to the signal line is reduced by the load on the display pixel of the display panel. May end up. Such deterioration of image quality due to insufficient driving capability of the gradation amplifier is particularly likely to occur in the intermediate gradation region.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a display driving device capable of suppressing a large deterioration in image quality in an intermediate gradation region, and a display device including the display driving device.

In order to achieve the above object, a display driving device according to the first aspect of the present invention is a display driving device that drives display pixels based on display data of a digital signal. A gradation voltage generating means for generating a plurality of gradation voltages corresponding to the level; and a gradation for selecting and outputting the gradation voltage corresponding to the gradation value of the display data from the plurality of gradation voltages Drive capability of the amplifying means when the gradation value of the display data is an intermediate gradation, the voltage selecting means, the amplifying means for amplifying and outputting the gradation voltage output from the gradation voltage selecting means and characterized by comprising a driving capability setting means for setting higher than the driving capability when the gradation value of the display data is high gray and low gray level.

In order to achieve the above object, a display driving device according to the second aspect of the present invention is a display driving device that drives display pixels based on display data of a digital signal. A gradation voltage generating means for generating a plurality of voltages corresponding to the gradation levels and generating a plurality of gradation voltages based on the plurality of voltages; and a gradation value of the display data from the plurality of gradation voltages Gradation voltage selection means for selecting and outputting the gradation voltage corresponding to the plurality of gradation voltages, wherein the gradation voltage generation means amplifies each of the plurality of voltages to generate the plurality of gradation voltages. And a driving capability of each of the amplifying units corresponding to the intermediate gray level of all the gray levels is set higher than a driving capability of each of the amplifying units corresponding to the high gray level and the low gray level. Driving capacity setting And having a means.

In order to achieve the above object, a display device according to the third aspect of the present invention includes a display having a plurality of display pixels arranged in a matrix in the vicinity of intersections of a plurality of scanning lines and a plurality of signal lines. In a display device that displays an image by driving a panel based on display data of a digital signal, scanning-side driving means that sequentially outputs scanning signals to the plurality of scanning lines to sequentially set the display pixels. Gradation voltage generating means for generating a plurality of gradation voltages corresponding to all gradation levels that can be taken by the display data; and the level corresponding to the gradation value of the display data from the plurality of gradation voltages. a gradation voltage selection means for selecting a tone voltage, a plurality of amplifying means for amplifying and outputting the gray scale voltages outputted from the gray scale voltage selecting means to said plurality of signal lines, said display de Wherein the drive capability of each amplifier means, the drive capability setting means gradation value of the display data is set higher than the driving capability when a high tone and the low tone when the gradation value of the data is halftone And a signal-side driving means having the above.

In order to achieve the above object, a display device according to a fourth aspect of the present invention includes a display having a plurality of display pixels arranged in a matrix in the vicinity of intersections of a plurality of scanning lines and a plurality of signal lines. In a display device that displays an image by driving a panel based on display data of a digital signal, scanning-side driving means that sequentially outputs scanning signals to the plurality of scanning lines to sequentially set the display pixels. Gradation voltage generating means for generating a plurality of voltages corresponding to all gradation levels that can be taken by the display data and generating a plurality of gradation voltages based on the plurality of voltages; and a gray-scale voltage selecting means for selecting the gray voltage corresponding to the gradation value of the display data from the gradation voltage generating means, said amplifying each of said plurality of voltage Multiple floors A plurality of amplifying means for generating a voltage, driving of the respective amplifying means for driving capability, corresponding to high gradation level and low gray levels of each amplifying means corresponding to the grayscale levels in the all gray levels characterized by comprising a signal-side drive means having a drive capability setting means for setting higher than the capability.

  According to the present invention, it is possible to provide a display driving device that can suppress a large deterioration in image quality in an intermediate gradation region, and a display device including the display driving device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram showing a configuration of a display device to which a display driving device according to a first embodiment of the present invention is applied. A display device 1 shown in FIG. 1 includes a display panel 10, a source driver (signal side driving means) 20, a gate driver (scanning side driving means) 30, an RGB decoder 40, a common voltage generation circuit 50, and a controller 60. And have.

  The display panel 10 includes a plurality of scanning lines arranged in the row direction and a plurality of signal lines arranged in the column direction, and the display pixels shown in FIG. 2 near the intersections of the scanning lines and the signal lines. Is provided.

  FIG. 2 is a diagram illustrating an equivalent circuit of one display pixel provided in the display panel 10. A gate electrode of a thin film transistor (TFT) 11 is connected to the scanning line G shown in FIG. 2, and a source electrode of the TFT 11 is connected to the signal line S. Further, the pixel electrode 12 of the liquid crystal capacitor and one electrode of the storage capacitor 14 are connected to the drain electrode of the TFT 11. The common electrode 13 of the liquid crystal capacitor and the other electrode of the storage capacitor 14 are connected to the common signal line C. Further, liquid crystal is filled between the pixel electrode 12 and the common electrode 13 to form a liquid crystal layer. In a display pixel having such a configuration, when a voltage is applied between the pixel electrode 12 and the common electrode 13, the liquid crystal filled between the pixel electrode 12 and the common electrode 13 according to the value of this voltage. The alignment state changes and the light transmittance in the liquid crystal layer changes. Thereby, the transmission state of light from a light source (not shown) arranged on the back surface of the display pixel shown in FIG. 2 is changed, and image display is performed.

  2 is connected to the source driver 20 and supplied from the RGB decoder 40 based on a horizontal control signal (clock signal, latch operation control signal, etc.) output from the controller 60 and a polarity inversion control signal. The display data of each color of R (red), G (green), and B (blue) is fetched in units of one row, and the gradation voltage corresponding to the fetched display data is selected and supplied to the signal line S. The operation of the source driver 20 will be described in detail later.

  2 is connected to the gate driver 30, receives a vertical control signal from the controller 60, and sequentially applies a scanning signal for turning on the TFT 11 for one row to each scanning line G. Is turned on, and the gradation voltage supplied from the source driver 20 via the signal line S is applied to the pixel electrode 12 in the display pixel at a position intersecting with the signal line S.

  The RGB decoder 40 extracts, for example, a horizontal synchronization signal, a vertical synchronization signal, and a luminance / color difference signal from a video signal (for example, a composite video signal) supplied from the outside of the display device 1 and supplies the extracted signal to the controller 60. Display data of each color of R, G, and B is generated from the color difference signal and output to the source driver 20.

  A common signal line C in FIG. 2 is connected to the common voltage generation circuit 50. The common voltage generation circuit 50 generates a common voltage Vcom whose polarity is inverted every predetermined period based on the polarity inversion control signal output from the controller 60 and applies the common voltage Vcom to the common signal line C.

  The controller 60 receives the vertical synchronization signal from the RGB decoder 40, generates a polarity inversion control signal and a vertical control signal, sends the polarity inversion control signal to the source driver 20 and the common voltage generation circuit 50, and sends the vertical control signal to the gate driver 30. Output to. Here, the polarity inversion control signal is a control signal for inverting the polarity of the gradation voltage applied to the liquid crystal layer every predetermined period (for example, every frame). Further, the controller 60 receives the horizontal synchronization signal from the RGB decoder 40, generates a horizontal control signal, and outputs it to the source driver 20.

Next, the operation of the display device 1 having the configuration as shown in FIG. 1 will be described.
When the vertical synchronization signal is supplied from the RGB decoder 40, the controller 60 generates a polarity inversion control signal and a vertical control signal. The polarity inversion control signal is output to the source driver 20 and the common voltage generation circuit 50, and the vertical control signal is output to the gate driver 30.

  When the polarity inversion control signal is input to the source driver 20, the polarity of the gradation voltage is inverted. Further, the gate driver 30 receives a vertical control signal and sequentially applies a scanning signal for turning on the TFT 11 for one row to each scanning line G.

  When a horizontal synchronization signal is supplied from the RGB decoder 40, a horizontal control signal is generated by the controller 60 and output to the source driver 20. Along with this, display data is output from the RGB decoder 40. The source driver 20 receives the horizontal control signal and takes in the display data from the RGB decoder 40, selects the gradation voltage corresponding to the fetched display data, and applies it to the corresponding signal line S.

  When a scanning signal is applied to the scanning line G and a gradation voltage is applied to the signal line S, the TFT 11 provided in the vicinity of these intersections is turned on, and the display pixel of the display pixel passes from the source electrode of the turned-on TFT 11 through the drain electrode. A gradation voltage from the signal line S is applied to the liquid crystal capacitor and the storage capacitor 14. A voltage corresponding to the difference between the applied gradation voltage and the common voltage is held in the liquid crystal capacitor and the storage capacitor. As a result, an electric field is generated between the pixel electrode 12 and the common electrode 13 of the liquid crystal capacitance, and the alignment state of the liquid crystal filled between the pixel electrode 12 and the common electrode 13 is changed by the strength of the electric field, so that the liquid crystal The light transmittance in the layer changes. Thereby, the transmission state of light from a light source (not shown) arranged on the back surface of the display pixel shown in FIG. 2 is changed, and image display is performed. The storage capacitor is provided in order to hold the voltage applied to the liquid crystal capacitor until the next gradation voltage is applied. In addition, the storage capacitor can suppress the influence of voltage change during inversion driving.

  Next, the source driver 20 will be further described. FIG. 3 is a detailed configuration diagram of a main part of the source driver 20 in the present embodiment. The source driver 20 shown in FIG. 3 includes a shift register 21, a data register 22, a data latch circuit 23, a gradation voltage generation circuit 24, a DAC 25, an output amplifier 26, and a drive capability setting circuit 27. ing.

  Each time the shift register 21 receives a clock signal from the controller 60, the shift register 21 outputs a control signal for causing the data register 22 to take in data. The data register 22 receives display data for one display pixel from the RGB decoder 40 (8-bit display data of D0 to D7 is shown in FIG. 3 but is not limited thereto). The display data input from the RGB decoder 40 is sequentially fetched in synchronization with the control signal.

  Each time the data latch circuit 23 receives a latch operation control signal from the controller 60, the data latch circuit 23 simultaneously fetches the display data held in the data register 22, and outputs the fetched display data to the DAC 25 corresponding to each display pixel.

  Here, in the first embodiment, two higher bits (D7 and D6 in the example of FIG. 3) out of the bits (8 bits of D0 to D7 in the example of FIG. 3) of the display data corresponding to one display pixel. Bit) is input not only to the DAC 25 but also to the drive capability setting circuit 27.

The gradation voltage generation circuit 24 generates a plurality of voltages corresponding to all gradation levels that the display data can take (in the example of FIG. 3, 256 gradation levels from 0 to 255 gradations), and amplifies the generated voltages. Then, a gradation voltage is generated and output to the DAC 25.
FIG. 4 is a diagram showing a detailed configuration of the gradation voltage generation circuit 24. As shown in FIG. 4, the gradation voltage generation circuit 24 includes a gradation voltage generation resistor group 241, a polarity changeover switch 242, a gradation amplifier 243, and a drive capability setting circuit 244.

  The gradation voltage generating resistor group 241 includes a number of resistance elements corresponding to the number of display gradations of each display pixel of the display panel 10, and includes a high level side power supply voltage VH supplied from a power supply circuit (not shown) and a low level. From the side power supply voltage VL, a plurality of gradation voltages (K0 to K255 in the example of FIG. 4) corresponding to all gradation levels that display data can take are generated by resistance division. The polarity switch 242 is a switch group that receives the polarity inversion control signal from the controller 60 and switches the polarity of the voltage generated by the gradation voltage generation resistor group 241. The gradation amplifier 243 amplifies each of the plurality of voltages generated by the gradation voltage generating resistor group 241 to generate gradation voltages K0 to K255. Note that the gradation amplifier 243 is composed of, for example, an operational amplifier having a voltage follower configuration. The drive capability setting circuit 244 generates a bias current control voltage for setting the drive capability of each gradation amplifier 243 from a predetermined reference current and supplies the voltage to each gradation amplifier 243. Here, a constant voltage is supplied to each gradation amplifier 243 from the driving ability setting circuit 244, and the driving ability of each gradation amplifier 243 is set to the same value.

  Further, the DAC 25 selects a gradation voltage corresponding to the gradation value of the display data for each display pixel input from the data latch circuit 23 and outputs it to the signal line S. The output amplifier 26 is provided for each signal line S, and drives the corresponding signal line S by the gradation voltage selected in the DAC 25. The output amplifier 26 is composed of, for example, an operational amplifier having a voltage follower configuration, and each driving capability is switched by a voltage supplied from the driving capability setting circuit 27. Here, when the H level signal is supplied from the drive capability setting circuit 27, the output amplifier 26 is set to a large value for the bias current of the operational amplifier constituting the output amplifier 26, and the drive capability is set high. The On the other hand, when an L level signal is supplied from the drive capability setting circuit 27, the bias current of the operational amplifier constituting the output amplifier 26 is set to a small value, and the drive capability is set low. Switching of the driving capability of the output amplifier 26 according to the signal level supplied from the driving capability setting circuit 27 is, for example, a gradation amplifier AMP based on a driving capability setting control signal AMPnH / L shown in FIG. 5 of the second embodiment described later. The same configuration as the switching of the driving ability can be used.

  The drive capability setting circuit 27 is provided corresponding to each output amplifier 26, and generates a voltage for setting the drive capability of the output amplifier 26 from the value of higher-order multiple bits of the display data input from the data latch circuit 23. The generated voltage is supplied to the output amplifier 26. Here, FIG. 3 shows an example of the circuit configuration of the drive capability setting circuit 27. As shown in FIG. 3, the drive capability setting circuit 27 is a coincidence circuit including, for example, two AND circuits 271 and 272, two inversion circuits 273 and 274, and one NOR circuit 275.

  The drive capability setting circuit 27 having such a circuit configuration outputs an L level signal to the corresponding output amplifier 26 when the values of the upper 2 bits D7 and D6 of the display data coincide with each other at the H level or the L level. When the value of the upper 2 bits D7 and D6 of the display data is one of the H level and the other is the L level, the drive capability setting circuit 27 outputs the H level signal to the corresponding output amplifier 26.

  With this configuration, the gradation value of the display data is a gradation value in which the values of the upper 2 bits D7 and D6 match, that is, a low gradation of 0 to 63 gradations corresponding to the gradation voltages of K0 to K63. In the area and the high gradation area of 192 to 255 gradations corresponding to the gradation voltage of K192 to 255, the drive capability of the output amplifier 26 is set low. On the other hand, when the gradation value of the display data is a gradation value in which the values of the upper 2 bits D7 and D6 do not match, that is, an intermediate gradation region corresponding to the gradation voltage of K64 to K191, the drive capability of the output amplifier 26 is high. Set high.

  As described above, according to the present embodiment, the drive capability of the output amplifier 26 in the intermediate gradation is made higher than the drive capability of the output amplifier 26 in the high gradation side and the low gradation side. In addition, it is possible to suppress deterioration in image quality in a large intermediate gradation region as compared with the high gradation side.

  In the example of FIG. 3, the driving capability of the output amplifier 26 is switched using the value of the upper 2 bits of the display data. However, the driving capability of the output amplifier 26 is not necessarily limited to 2 bits. The number of circuits may be increased and the driving capability may be switched using a value of 3 bits or more.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the second embodiment, the driving capability is set in advance for each gradation level, not the value of the display data input to the source driver 20.

  FIG. 5A is a diagram showing a configuration of the gradation voltage generation circuit 24 in the second embodiment. In FIG. 5A, the description of the configuration of the same part as in FIG. 4 is omitted. As shown in FIG. 5A, in the second embodiment, the voltage that can be set in the driving capability setting circuit 245 is the voltage level H for increasing the driving capability of the gradation amplifier 243 and the driving of the gradation amplifier 243. Two types of voltage L level for lowering the capability and a driving capability changeover switch 246 for selectively supplying the two types of voltages set in the driving capability setting circuit 245 to each gradation amplifier 243. Is different from the first embodiment. Although not shown, the driving capability setting circuit 27 is also not provided, which is different from the first embodiment.

  As shown in FIG. 5A, the drive capability changeover switch 246 corresponding to one gradation amplifier AMPn (n = 1, 2,..., 64,...) Is composed of a set of a switch AMPnH and a switch AMPnHB. These switches are commonly connected to the bias voltage supply terminal of the gradation amplifier AMPn. For example, control signals AMPnH and AMPnHB generated from the drive capability setting control signal AMPnH / L supplied from the controller 60 are supplied to the switch AMPnH and the switch AMPnHB, respectively. The switch AMPnH is turned on when the control signal AMPnH is at the H level and turned off when the control signal AMPnH is at the L level. On the other hand, the switch AMPnHB is turned on when the control signal AMPnHB is at the H level and turned off when it is at the L level.

  FIG. 5B is a configuration diagram for generating the control signals AMPnH and AMPnHB from the drive capability setting control signal AMPnH / L. In the configuration shown in FIG. 5B, when an H level signal is input as AMPnH / L, AMPnH becomes H level and AMPnHB becomes L level. As a result, the switch AMPnH is turned on and the AMPnHB is turned off. When an L level signal is input as AMPnH / L, AMPnH is at L level and AMPnHB is at H level. As a result, the switch AMPnH is turned off and the AMPnHB is turned on.

  In the configuration as described above, in the present embodiment, the driving ability in the vicinity of the intermediate gradation is made higher than the driving ability in the high gradation and the low gradation. For example, in the case of 256 gradations, an L level signal is supplied as the driving ability setting control signal AMPnH / L to the driving ability changeover switch 246 corresponding to the vicinity of the gradation amplifier AMP1 and the gradation amplifier AMP255 on the low gradation side. Then, an H level signal is supplied to the drive capability changeover switch 246 corresponding to the vicinity of the intermediate gradation as the drive capability setting control signal AMPnH / L.

  Here, for setting the signal level of each drive capability setting control signal AMPnH / L supplied from the controller 60, for example, a register for setting the drive capability setting control signal is provided in the source driver 20, and driven from an external CPU. The register may be set by a control signal sometimes supplied, or a signal input terminal for setting a drive capability setting control signal is provided in the source driver 20, and the signal input terminal It may be fixedly set by applying a desired signal level to it, and it may be fixedly set by setting a mask of a wiring pattern at the time of manufacturing the source driver 20. Also good.

  Even in the configuration of the second embodiment as described above, it is possible to suppress deterioration in image quality in a large intermediate gradation region as compared with the low gradation side and the high gradation side. In the second embodiment, the driving capability of the gradation amplifier 243 is changed according to the gradation level, but the configuration of FIG. 5A is applied to the output amplifier 26 to drive the output amplifier 26. May be changed according to the gradation level.

  The example of FIG. 5A describes an example in which the driving capability of the gradation amplifier 243 is changed in two stages. However, the voltage level that can be generated in the driving capability setting circuit 245 is set to three or more levels, and the driving capability is switched. By increasing the number of switches of the switch 246, the driving capability of the gradation amplifier 243 can be made variable in three steps or more.

  Although the present invention has been described based on the above embodiments, the above-described embodiments include various stages of the invention, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some configuration requirements are deleted from all the configuration requirements shown in the embodiment, the above-described problem can be solved, and this configuration requirement is deleted when the above-described effects can be obtained. The configuration can also be extracted as an invention.

It is a figure which shows the structure of the display apparatus to which the display drive device which concerns on the 1st Embodiment of this invention is applied. It is a figure which shows the equivalent circuit of one display pixel provided in a display panel. It is a detailed block diagram of the principal part of the source driver in 1st Embodiment. It is a figure which shows an example of the circuit structure of the gradation voltage generation circuit in 1st Embodiment. FIG. 5A is a diagram showing an example of the circuit configuration of the gradation voltage generation circuit in the second embodiment, and FIG. 5B generates control signals AMPnH and AMPnHB from the drive capability setting control signal AMPnH / L. It is a block diagram for doing.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Display panel, 20 ... Source driver, 21 ... Shift register, 22 data register, 23 ... Data latch circuit, 24 ... Gradation voltage generation circuit, 25 ... DAC, 26 ... Gradation amplifier, 27 ... Drive capability setting circuit, 30 ... Gate driver, 40 ... RGB decoder, 50 ... Common voltage generation circuit, 60 ... Controller

Claims (7)

In a display driving device that drives display pixels based on display data of digital signals,
Gradation voltage generating means for generating a plurality of gradation voltages corresponding to all gradation levels that can be taken by the display data;
A gradation voltage selecting means for selecting and outputting the gradation voltage corresponding to the gradation value of the display data from the plurality of gradation voltages;
Amplifying means for amplifying and outputting the gradation voltage output from the gradation voltage selecting means;
Driving capability setting for setting the driving capability of the amplifying means when the gradation value of the display data is an intermediate gradation higher than the driving capability when the gradation value of the display data is a high gradation and a low gradation. Means,
A display driving device comprising: 2. The display driving device according to claim 1 , wherein the driving capability setting unit sets the driving capability of the amplifying unit based on a value of higher-order multiple bits of the display data. The drive capability setting means determines that the current value of the bias current supplied to the amplifying means is equal to the value of the upper multiple bits of the display data when the values of the upper multiple bits of the display data do not match. If the display data gradation value is set to a value larger than the current of the bias current supplied to the amplification means, the drive capability of the amplification means when the gradation value of the display data is an intermediate gradation is set to 3. The display driving device according to claim 2 , wherein the display driving device is set to be higher than the driving capability of the amplifying means when the gradation value is a high gradation and a low gradation. In a display driving device that drives display pixels based on display data of digital signals,
Gradation voltage generating means for generating a plurality of voltages corresponding to all gradation levels that the display data can take, and generating a plurality of gradation voltages based on the plurality of voltages;
A gradation voltage selecting means for selecting and outputting the gradation voltage corresponding to the gradation value of the display data from the plurality of gradation voltages;
With
The gradation voltage generation means includes a plurality of amplification means for amplifying each of the plurality of voltages to generate the plurality of gradation voltages, and each of the amplifications corresponding to intermediate gradation levels in all the gradation levels. And a driving capability setting unit for setting the driving capability of the unit to be higher than the driving capability of each of the amplifying units corresponding to the high gradation level and the low gradation level . The drive capability setting means is configured to use a current value of a bias current supplied to the amplifying means corresponding to the intermediate gradation level as a current of a bias current supplied to the amplifying means corresponding to the high gradation level and the low gradation level. The driving capability of the amplifying unit corresponding to the intermediate gradation level is set higher than the driving capability of the amplifying unit corresponding to the high gradation level and the low gradation level. The display driving device according to claim 4 . In a display device that displays an image by driving a display panel having a plurality of display pixels arranged in a matrix in the vicinity of each intersection of a plurality of scanning lines and a plurality of signal lines based on display data of a digital signal,
Scanning-side driving means for sequentially outputting scanning signals to the plurality of scanning lines to sequentially set the display pixels in a selected state;
Gradation voltage generating means for generating a plurality of gradation voltages corresponding to all gradation levels that can be taken by the display data; and the level corresponding to the gradation value of the display data from the plurality of gradation voltages. A gradation voltage selecting means for selecting and outputting a regulated voltage; a plurality of amplifying means for amplifying the gradation voltage output from the gradation voltage selecting means and outputting to the plurality of signal lines; and the display data Driving capability setting means for setting the driving capability of each of the amplifying means when the gradation value of the display data is an intermediate gradation higher than the driving capability when the gradation value of the display data is a high gradation and a low gradation ; And signal side driving means having
A display device comprising: In a display device that displays an image by driving a display panel having a plurality of display pixels arranged in a matrix in the vicinity of each intersection of a plurality of scanning lines and a plurality of signal lines based on display data of a digital signal,
Scanning-side driving means for sequentially outputting scanning signals to the plurality of scanning lines to sequentially set the display pixels in a selected state;
Gradation voltage generating means for generating a plurality of voltages corresponding to all gradation levels that can be taken by the display data and generating a plurality of gradation voltages based on the plurality of voltages; Gradation voltage selection means for selecting and outputting the gradation voltage corresponding to the gradation value of the display data from, wherein the gradation voltage generation means amplifies each of the plurality of voltages to A plurality of amplifying means for generating a plurality of gradation voltages, and a driving capability of each of the amplifying means corresponding to the intermediate gradation levels in all the gradation levels, the respective driving ability corresponding to the high gradation level and the low gradation level. Driving capability setting means for setting higher than the driving capability of the amplifying means, signal side driving means having,
A display device comprising:

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