JP2006189684A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform video display with image quality and definition meeting required by video information to be displayed according to the video information in a liquid crystal display device equipped with a liquid crystal display panel having a plurality of sub-pixels in respective unit pixels and capable of performing gray scale display. <P>SOLUTION: The liquid crystal display device is equipped with a voltage supply means for discretely supplying a voltage of a prescribed voltage value in addition to the gray scale voltage supplied from a source electrode to each of the plurality of the sub-pixels within the unit pixel. A controller 4 adjusts the voltage value supplied by the voltage supply means discretely by the each sub-pixel according to the video information, such as display mode selection, in a user operation section 2, and performs display control of the liquid crystal display panel 8 by correcting the gray scale characteristics of the unit pixels changed by the adjustment processing. The liquid crystal display device is previously provided, as the voltage supply means, with, for example, auxiliary capacitance reference electrode to which the respective sub-pixels within the auxiliary capacitance unit pixel in the liquid crystal display panel 8 are separately connected, and the voltage values read out of a ROM 6 by an auxiliary capacitance signal generating circuit 7 are supplied by each of the respective sub-pixels from the respective auxiliary capacitance reference electrodes. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device including a liquid crystal display panel having a plurality of subpixels in each unit pixel.

  In a liquid crystal display device capable of gradation display, in order to widen the viewing angle, each pixel electrode is divided into a plurality of subpixel electrodes, and drive voltages applied to the pixel electrodes are applied to the subpixel electrodes at different ratios. For example, the pixel electrode is divided into a plurality of sub-pixels, and the thickness of the liquid crystal cell is varied for each sub-pixel within the same pixel electrode.

A gradation liquid crystal display panel has also been proposed that has symmetrical visual characteristics of upper, lower, and (left, right) and aims to widen the viewing angle without gradation inversion (for example, Patent Document 1). See). In the gradation liquid crystal display panel described in Patent Document 1, the pixel electrode is divided into sub-pixel electrodes, and a driving voltage is applied to these sub-pixel electrodes at different ratios. Further, for each sub-pixel electrode or within the sub-pixel electrode, The pretilt angle is changed or the rubbing direction is reversed.
JP-A-6-332009

  However, if a technique for applying a drive voltage at a different ratio to subpixel electrodes such as Patent Document 1 is employed and the voltage between subpixel electrodes is set to an extremely different value, the viewing angle characteristics of contrast On the other hand, since the difference in gradation between pixels becomes extremely large, a bright and dark pattern is visually recognized between sub-pixels, and it is difficult to provide a user with a sufficiently high image quality image. In particular, for still images that are frequently displayed as personal computer (PC) screens, the bright and dark patterns as described above are highlighted when the user views them, and fine characters and diagonal edges appear jagged. End up.

  In addition, when viewing the screen from the front at the same time as viewing the screen from the front, the color of the mixed color generated by the color mixture between the sub-pixels becomes unnatural. In particular, the hue of intermediate colors such as flesh color deviates from the target hue.

  The present invention has been made in view of the above circumstances, and in a liquid crystal display device including a liquid crystal display panel having a plurality of sub-pixels in each unit pixel and capable of grayscale display, display is performed by a user or a main body. Depending on the video information to be displayed, such as the display mode selected as a result of detecting the type of video to be optimized, the video display at the image quality and resolution required for the video information is optimized for the subpixel voltage ratio. This is possible and can be caused by optimizing the voltage ratio between sub-pixels in order to improve the viewing angle characteristics, and the gradation due to changes in gradation characteristics (γ characteristics) (especially significant changes in halftone). The object is to make it possible to eliminate the floating or sinking phenomenon of tonal characteristics.

The present invention is constituted by the following technical means in order to solve the above-described problems.
A first technical means includes a liquid crystal display panel having a plurality of unit pixels connected to a source electrode and a gate electrode, and having a plurality of subpixels in each unit pixel and capable of gradation display, and a display target. And a control unit that performs display control of video information on the liquid crystal display panel according to video information, wherein the source electrode is provided for each of a plurality of sub-pixels configured in the unit pixel. Voltage supply means for individually supplying a voltage having a predetermined voltage value in addition to the gradation voltage supplied from the control circuit, and the control means supplies the voltage value supplied by the voltage supply means in accordance with the video information. And a gradation characteristic correcting means for correcting the gradation characteristic of the unit pixel changed by the adjustment process of the adjusting means.

  According to a second technical means, in the first technical means, the voltage supply means has an auxiliary capacitance reference electrode to which each sub-pixel in the unit pixel is separately connected, and the voltage is supplied from each auxiliary capacitance reference electrode. A value is supplied for each sub-pixel.

  According to the present invention, in a liquid crystal display device having a gradation displayable liquid crystal display panel having a plurality of subpixels in each unit pixel, a display selected as a result of user selection or detection of the type of video to be displayed on the main body Depending on the video information to be displayed, such as the mode, video display with the image quality and resolution required for the video information can be achieved by optimizing the voltage ratio between subpixels, and viewing angle characteristics To eliminate the floating or sinking phenomenon of gradation characteristics due to changes in gradation characteristics (γ characteristics) (especially significant changes in halftones), which can occur by optimizing the voltage ratio between subpixels to improve It becomes possible to do.

  The liquid crystal display device according to the present invention includes a liquid crystal display panel capable of displaying the next gradation, voltage supply means, and control means. This liquid crystal display panel has a plurality of unit pixels connected to the source electrode and the gate electrode, and has a plurality of sub-pixels in each unit pixel. The control means controls display of the video information on the liquid crystal display panel according to the video information to be displayed on the liquid crystal display panel.

  The voltage supply means individually supplies a voltage having a predetermined voltage value to each of the plurality of subpixels configured in the unit pixel. Therefore, in addition to the voltage supplied from the gate electrode and the gradation voltage supplied from the source electrode, a voltage supplied to each subpixel by this voltage supply means is applied to the liquid crystal display panel. This voltage may be applied to the auxiliary capacitance provided in each sub-pixel, and therefore this voltage supply means can be said to be auxiliary voltage supply means. According to the present invention, the control means includes an adjustment means for adjusting the voltage value supplied by the voltage supply means for each sub-pixel according to video information, and a gradation characteristic of the unit pixel changed by the adjustment processing of the adjustment means. Gradation characteristic correcting means for correcting the above.

  FIG. 1 is a block diagram showing a configuration example of a liquid crystal display device according to an embodiment of the present invention, in which 1 is a video signal input unit, 2 is a user operation unit, and 3 is a microcomputer (hereinafter referred to as a microcomputer). ), 4 is a controller, 5 is a source driver (source drive circuit), 6 is a ROM, 7 is an auxiliary capacitance signal generation circuit, 8 is a liquid crystal display panel, 9 is a gate driver (gate drive circuit), and 10 is a γ characteristic correction unit. Reference numeral 10a denotes a reference gradation voltage generator, and 10b denotes a ROM for the reference gradation voltage generator 10a.

Also, FIG. 2 is a diagram showing an example of an equivalent circuit of the liquid crystal display panel in the liquid crystal display device of FIG. 1, in the drawing, P unit pixel, P _A sub-pixel A, P _B sub-pixel B, S ₁ , _{S 2} denotes a source electrode, G ₁ denotes a gate electrode, _{H a} is an auxiliary capacitor reference electrode for the sub-pixel a, _{H B} is an auxiliary capacitor reference electrode for the sub-pixel B, the liquid crystal layer of _{L a} sub-pixel a, _{L B} is the liquid crystal layer of the subpixel B, the _{T a} sub-pixel a TFT, _{T B} is the sub-pixel B TFT, an auxiliary capacitor of _{C a} sub-pixel a, _{C B} is the auxiliary capacitor of the sub-pixel B.

  In addition to the video signal input unit 1 and the liquid crystal display panel 8, the liquid crystal display device illustrated in FIG. 1 includes a user operation unit 2, a microcomputer 3, a controller 4, a source driver 5, a gate driver 9, And an γ characteristic correction unit 10 and an active matrix type configuration, and further includes a ROM 6 and an auxiliary capacitance signal generation circuit 7 as an example of the voltage supply means described above.

  The user operation unit 2 receives a selection operation for selecting a display mode for video information to be displayed from the user. Then, the adjustment unit adjusts the voltage value supplied by the voltage supply unit individually for each sub-pixel according to the type of display mode selected by the user operation unit 2. This adjustment means is exemplified by the microcomputer 3 that sends a control signal corresponding to the mode selection operation received by the user operation unit 2 to the controller 4.

  The video signal input unit 1 inputs a video signal of a moving image or a still image to be displayed by an instruction operation or default setting by a user, and outputs it to the controller 4. Here, the input video signal may be switched by an instruction operation other than the display mode selection from the user operation unit 2. As this instruction operation, for example, when the power is turned on by the power button 2a of the remote controller (hereinafter referred to as remote controller), the previous setting is read and the input video signal is selected, the direction instruction and decision key 2c or the selection key is selected. For example, the input video signal can be selected after the power is turned on by the station and the position key 2d.

  In the user operation unit 2, display mode selection may be selected by, for example, the mode switching button 2 b of the remote controller or the direction instruction and determination key 2 c and the result may be sent to the microcomputer 3. The display mode may be set so as to be selected in accordance with switching of input sources such as TV, video 1, video 2 and PC. In this case, the microcomputer 3 is provided with an input source switching button instead of or separately from the mode switching button 2b, and a display mode corresponding to the input source of the TV mode / video mode / PC mode according to the operation. Determine. The input source switching button may be a button that is repeated in the order of the television mode, the video 1 mode, the video 2 mode, and the PC mode each time the button is pressed. Furthermore, even if the input source is the same (for example, the same input source is the same television), it is preferable that the display mode selected by the user can be selected so that display control according to the user can be performed.

  The microcomputer 3 issues a command to the controller 4 based on the display mode selection result from the user operation unit 2 to control the controller 4. The controller 4 controls the storage capacitor signal generation circuit 7 in addition to the control of the source driver 5 and the gate driver 9, so that video information to be displayed on the liquid crystal display panel 8 (that is, input by the video signal input unit 1). Display control of the liquid crystal display panel 8 according to the display mode selection result in the user operation unit 2.

  The controller 4 includes, for example, a drive voltage generation unit, a drive signal generation unit, and an LUT (Look Up Table) (not shown). The drive voltage generation unit generates a drive voltage value to be applied to the source electrode of the liquid crystal display panel 8 and sends the voltage value to the source driver 5. The LUT is a conversion table for converting image data, which is display data, so as to ensure gradation characteristics at a wide viewing angle when displaying image data on the liquid crystal display panel 8. That is, the LUT receives the same data as the image data input to the drive signal generation unit, and transmits the result referred to in the conversion table based on the input image data to the drive signal generation unit. .

  The drive signal generation unit includes a pixel data conversion unit, a horizontal synchronization signal generation unit, and a vertical synchronization signal generation unit (not shown). The pixel data conversion unit converts the input image data based on the LUT reference result, and sends it to the source driver 5 as source drive image data. The horizontal sync signal generator generates horizontal source driving sources such as a source clock for controlling data capture from the input image data, a source start pulse for indicating the start of data, and a latch pulse for controlling switching of the source output. A synchronization signal is generated, and the generated signal (control signal for driving the source) is sent to the source driver 5. In addition, the vertical synchronization signal generator generates a gate drive vertical synchronization signal such as a gate clock indicating the shift timing of the gate bus line to be applied and a gate start pulse indicating the start of frame switching from the input image data. The generated signal (gate drive control signal) is sent to the gate driver 9. As described above, the drive signal generation unit generates a drive signal for operating the source driver 5 and the gate driver 9 based on the video information (image data) input by the video signal input unit 1 and the LUT reference result. And output to each. In the present invention, at least the input is performed in the drive signal generation unit due to the presence of display control (and gradation characteristic correction control described later) based on the video information according to the present invention (illustrated in the display mode here). Since it is sufficient to output the processed image data as a value for each sub-pixel as it is, it is not necessary to perform data conversion in the LUT, that is, it is not necessary to provide the LUT. In addition, when performing data conversion in the LUT, it is necessary to perform display control based on video information according to the present invention (and gradation characteristic correction control described later).

  The source driver 5 is a source arranged vertically to the liquid crystal display panel 8 to drive the liquid crystal display panel 8 based on the signal from the drive signal generation unit and the drive voltage value generated by the drive voltage generation unit. It is a circuit that applies a voltage having a voltage value sent from the drive signal generator to the bus line.

  The gate driver 9 applies an active matrix driving voltage to a gate bus line arranged horizontally on the liquid crystal display panel 8 in order to drive the liquid crystal display panel 8 based on a signal from the drive signal generation unit. Circuit. That is, a voltage is selectively applied to the gate bus line based on a signal from the drive signal generation unit.

The liquid crystal display panel 8 is an active matrix type display panel in which a plurality of unit pixels are arranged in a matrix, and a source bus line (source electrode) and a gate bus line (gate electrode) by a source driver 5 and a gate driver 9. Is operated by applying a voltage to the display, and an image based on the input image information is displayed. That is, the liquid crystal display panel 8 includes a source electrode S (S ₁ , S ₂ ,...) And a gate electrode G (G ₁ , G ₂ (not shown),. ..) and a plurality of unit pixels P connected to each other. The liquid crystal display panel 8 according to the present invention has a plurality of sub-pixels H (illustrated by two sub-pixels P _A and P _B in each unit pixel P).

Sub-pixel _{P A} is the liquid crystal layer _{L A} and the auxiliary capacitor _{C A} is connected to the TFT _{(T A).} TFT to the gate of the (T _A) is the gate electrode G is connected, the source electrode S ₁ is connected to the source side, further, the other end of the auxiliary capacitor C _A is connected to the storage capacitor reference electrode H _A, voltage applied to the liquid crystal layer L _a is adapted to be adjusted auxiliary. Similarly, the sub-pixel P _B includes the liquid crystal layer L _{B and the} auxiliary capacitor C _B connected to the TFT (T _B ). The gate electrode G is connected to the gate side of the TFT (T _B ), the source electrode S ₁ is connected to the source side, and the other end of the auxiliary capacitor C _B is connected to the auxiliary capacitor reference electrode H _B. voltage applied to the liquid crystal layer L _B is adapted to be adjusted auxiliary. In this embodiment, as the above-described voltage supply means, for example, an auxiliary capacitance reference electrode is provided in the liquid crystal display panel 8, and the voltage value read from the ROM 6 by the auxiliary capacitance signal generation circuit 7 is transferred from each auxiliary capacitance reference electrode to each sub capacitance It is configured to supply each pixel.

As described above, the liquid crystal display panel 8 includes the source electrodes S ₁ , S ₂ ,. . . And gate electrodes G ₁ , G ₂ ,. . . Are orthogonal to each other, and a pixel electrode and a transistor for driving the pixel electrode are arranged at the intersection. A driving voltage from the gate driver 9 can be applied to two columns of sub-pixel electrodes with _one gate electrode G (for example, G ₁ ). That is, the red (R), green (G), and blue (B) pixel electrodes constitute one pixel P by the sub-pixels P _A and P _B divided into two. Display in the pixel P is made by the average value of the sub-pixels P _A and P _B.

Then, the auxiliary capacitance signal generating circuit 7, based on the adjustment control of the controller 4 according to the type of display mode selected by the user, the auxiliary capacitor reference electrode H _A for the sub-pixel P _A, an auxiliary capacitor for the sub-pixel P _B for each of the reference electrodes H _B, a predetermined voltage value for the adjustment control (P _a, P for _B) with reference to the ROM6 which a plurality prestored sets of supplies individually voltage of a predetermined voltage value. The ROM 6 for the auxiliary capacitance signal generation circuit 7 stores a voltage value to be sent to each auxiliary capacitance reference electrode corresponding to the type of display mode. Therefore, in addition to the voltage supplied from the gate electrode and the gradation voltage supplied from the source electrode, the liquid crystal display panel 8 is applied with a voltage supplied individually to the sub-pixels by the auxiliary capacitance signal generating circuit 7. It becomes. This voltage may be applied to the auxiliary capacitance provided in each subpixel. Further, data may be stored in the ROM 6 so that the voltage of a predetermined value supplied to each sub-pixel is a voltage supplied with a different polarity for each sub-pixel pair.

  However, with only the control as described above, by adding the voltage value stored in the ROM for the auxiliary capacitance signal generation circuit to the video signal, each subpixel has a voltage value slightly different from the actual video signal. Since the voltage is supplied, the voltage value of each gradation deviates from an ideal γ characteristic. In particular, a shift at a low gradation number has a large effect. For this reason, it is preferable to correct this low gradation γ characteristic. Therefore, in the present embodiment, such γ characteristic correction can be executed. In the following description, the display control based on the display mode selection by the user as described above will be described as a base. However, as will be exemplified later, it is only necessary that the display control according to the video information is possible.

  The γ characteristic correcting means is a means for supplementing the process of adjusting the voltage value supplied by the voltage supplying means according to the video information in the adjusting means for each sub-pixel, and is a unit pixel that is changed by the adjusting process in the adjusting means This is a means for correcting the gradation characteristics. In the present embodiment, as this γ characteristic correction means, a γ characteristic correction unit 10 (in the controller 4 or a part thereof may be provided in the source driver 5) having a reference gradation voltage generation unit 10a and a ROM 10b for the reference gradation voltage generation unit 10a. ) And the γ characteristic correction unit 10 is configured to be able to change the reference gradation voltage.

  Here, the control means in this embodiment is exemplified by the microcomputer 3 that sends a control signal corresponding to the mode selection operation received by the user operation unit 2 to the controller 4 and the reference gradation voltage generation unit 10a.

  The microcomputer 3 issues a command to the controller 4 based on the display mode selection result from the user operation unit 2 to control the controller 4, and also to the γ characteristic correction unit 10 (reference gradation voltage generation unit 10a). Control is performed by issuing a command based on the display mode selection result.

In the reference gradation voltage generator 10a, a reference voltage value is assigned in advance to a plurality of arbitrarily extracted gradation numbers among the gradation numbers from 0 to 255. For example, V ₁₆ , V ₃₂ , and V ₄₈ are assigned as reference voltage values to the gradation numbers ₁₆ , ₃₂ , and ₄₈ , and V ₃₂ is set to a voltage value between V _{16 and} V ₄₈ . Then, it is possible this sequence of reference gradation voltage is written in each mode or detected video signals to ROM10b for reference gray-scale voltage generating unit 10a, to adjust the value of example V ₃₂ each mode. This method also makes it possible to correct an ideal γ characteristic for a video signal to which a predetermined voltage has been added once. Next, a processing example in the γ characteristic correction unit as a feature of the present embodiment will be described in detail.

  FIG. 3 is a diagram for explaining an example of the γ correction process in the liquid crystal display device of FIG. 1. In FIG. 3, reference numeral 10c denotes a correction based on the reference gradation data used for the γ correction process (a correction based on the reference gradation voltage). 3 is a table showing an example of three reference gradation data for an input gradation.

  As shown in Table 10c, the reference gradation data 1, reference gradation data 2, and reference gradation data 3 are stored in the ROM 10b for the input gradation. For example, the reference gradation data 1 is an example of reference gradation voltage data that is applied when the potential difference of the voltage applied to the reference electrode of the auxiliary capacitor is small with respect to the input gradation data. For input gradation data of 0, 32, 64, 96, 128, 192, and 255, data having reference gradation voltages of 900, 600, 400, 300, 250, 180, and 100 are prepared.

  The reference gradation data 2 is an example of reference gradation voltage data applied when the potential difference of the voltage applied to the reference electrode of the storage capacitor is medium with respect to the input gradation data. Data having reference gradation voltages of 900, 700, 450, 350, 270, 190, and 100 are prepared for input gradation data of 0, 32, 64, 96, 128, 192, and 255, respectively. The reference gradation data 3 is an example of reference gradation voltage data applied when the potential difference of the voltage applied to the reference electrode of the auxiliary capacitor is larger than the input gradation data. Data having reference gradation voltages of 900, 800, 500, 400, 300, 200, and 100 are prepared for input gradation data of 0, 32, 64, 96, 128, 192, and 255, respectively.

  Based on the control signal output from the microcomputer 3 (control signal corresponding to the mode selection operation accepted by the user operation unit 2), the reference gradation voltage generation unit 10a receives reference gradation data corresponding to the control signal from the ROM 10b. Is output to the source driver 5. For example, when a control signal is sent by a potential difference such as potential difference 1, potential difference 2, potential difference 3 as the control level of the microcomputer 3, reference gradation data 1, reference gradation data 2, reference gradation data corresponding to each potential difference. 3 is read from the ROM 10 b and output to the source driver 5.

  FIG. 4 is a diagram illustrating an example of a gradation voltage generation unit in the source driver corresponding to the reference gradation voltage generation unit in the liquid crystal display device of FIG. In the figure, 20 is an example of a voltage generator in the source driver 5 corresponding to the reference gradation voltage generator 10a.

The voltage generator 20 has terminals VA ₀ , VA ₃₂ ,... For inputting input gradation data of ₀ , ₃₂ , 64, 96, 128, 192, 255. . . , VA ₂₅₅ . These terminals are connected to resistors Ra, Rb,. . . , Rg. A resistance is further provided for subdivision between these gradations. For example, in order to control a fine output voltage between the terminal VA ₀ and the terminal VA ₃₂ , resistors r ₁ , r ₂ ,. . . , R ₃₂ .

The reference gradation voltage generator 10 a refers to the ROM 10 b in response to the control signal from the microcomputer 3, obtains reference gradation data corresponding to each input gradation, and outputs the voltage value to the source driver 5. On the other hand, in the voltage generation unit 20, the input voltages (900, 600, 400, 300, 250, 180, 100V in the case of the reference gradation data 1) illustrated in Table 10c corresponding to each input gradation are respectively connected to the terminal VA. ₀ , VA ₃₂ ,. . . , VA ₂₅₅ and the output terminals Vd ₀ , Vd ₁ ,. . . , Vd ₂₅₅ is selected. Through such processing, the reference gradation voltage itself is corrected (γ characteristic correction), and the auxiliary capacitance signal generation circuit 7 responds to the image data (video information) (in this example, according to the display mode). It is possible to apply an auxiliary capacitance reference voltage for each subpixel.

  FIG. 5 is a diagram illustrating an example of a main part of the reference gradation voltage generation unit in the liquid crystal display device of FIG. In the figure, 21 is an example of a voltage generator in the reference gradation voltage generator 10a, 22a, 22b,. . . Are D / A converters (DAC), 23a, 23b,. . . Is an amplifier.

The voltage generator 21 illustrated in FIG. 5 is different from the voltage generator 20 of FIG. 4 in that the reference gradation voltage itself is not changed, and the gradation based on the line segment between the gradations is digitally generated by the DAC and the amplifier. Correction (γ characteristic correction) is performed by changing the control. For example, when the input gradation data is 32, VA ₃₂ data (data 600 in the case of the reference gradation data 1 is input to the voltage generation unit 21) is input to the DAC 22b and amplified by the amplifier 23b. The output voltage Vd ₃₂ is output to the source driver 5. The conversion value in each DAC may be given from the microcomputer 3 side. This process is heavier than the process described in FIG. 4, but if it is 8 bits, it is output as 8 bits. Through such processing, the reference gradation voltage is corrected by correcting the input signal (γ characteristic correction), and further, according to the image data (video information) by the auxiliary capacitance signal generating circuit 7 (however, in this example) Then, it is possible to apply an auxiliary capacitance reference voltage for each sub-pixel (according to the display mode).

  FIG. 6 is a flowchart for explaining an example of control in the liquid crystal display device of FIG. In the liquid crystal display device according to the present embodiment, control is started when the user performs a selection operation (step S1) of a display mode (also referred to as a video mode) with the above-described configuration. Hereinafter, examples in which a theater mode (for example, corresponding to a display mode for high-definition broadcast display), a PC mode, and a normal broadcast mode are prepared as display modes to be selected and switched will be described.

  When the theater mode is selected in step S1 (YES in step S2), auxiliary capacity reference electrode control data for the theater mode and gradation reference voltage control data for the theater mode are read (step S3). Is output (step S4). If NO in step S2, it is determined whether the PC mode has been selected (step S5). When the PC mode is selected, the auxiliary capacity reference electrode control data for the PC mode and the gradation reference voltage control data for the PC mode are read (step S6), and these data are output (step S4). Further, if NO in step S5, it is determined that the remaining normal broadcast mode has been selected, and the auxiliary capacity reference electrode control data for the normal broadcast mode and the gradation reference voltage control data for the normal broadcast mode. Is read (step S7), and the data is output (step S4).

Further, in step S4, 1 frame or every one field per aid to each other (the liquid crystal for each unit screen data to be input to the display panel 8) volume reference electrode H _A, auxiliary volume basis by switching the applied voltage to the H _B By controlling the output of the electrode control data and the gradation reference voltage control data, it may be controlled to suppress the light / dark difference due to the voltage difference of the storage capacitor electrode. In this embodiment, the control means may be provided with switching means for switching the voltage value in the adjustment means between the sub-pixels every predetermined number of frames. For example, the control unit performs control so that voltages having predetermined values individually supplied to the sub-pixels of the pair are alternately switched every predetermined number of frames.

  FIG. 7 is a diagram for comparing the voltage difference enhancement processing between sub-pixels according to the present invention with a conventional example. In FIG. 7, reference numeral 31 denotes a change in the luminance ratio for each gradation according to the viewing angle according to the conventional example as VA (vertical alignment). ) FIG. 32 is a graph for explaining the liquid crystal as an example. FIG. 32 is a diagram for explaining the variation of the luminance ratio for each gradation due to the viewing angle by the voltage difference enhancement processing between the sub-pixels (normal broadcast mode processing and cinema mode processing). A graph diagram, 32a is a schematic diagram of the light / dark difference of each sub-pixel in the enhancement process, and 33 is a view of the luminance ratio for each gradation by a process (PC mode process) slightly emphasizing the voltage difference between the sub-pixels. FIG. 33a is a graph for explaining the variation, 33a is a schematic diagram of the contrast difference of each subpixel in the enhancement process, and 34 is the brightness difference of each subpixel when the frame / field switching process is further applied to those processes. It is a schematic diagram. In FIG. 7, the solid line indicates 0 ° (front view), the broken line indicates ± 45 °, and the dotted line indicates ± 60 °.

Referring to FIG. 7, in the control in the normal broadcast mode process and the cinema mode process, a difference in brightness due to the voltage difference of the auxiliary capacitance reference electrode between the sub-pixels is more easily generated. On the other hand, it is possible to further eliminate a decrease in contrast at a wide viewing angle, that is, to improve contrast when viewed from an oblique direction. Such control is suitable for moving image specifications that require a wider viewing angle. For this control, by switching to a frame or every each field (each unit screen data to be input to the liquid crystal display panel 8) to each other of the auxiliary capacitor reference electrode H _A, the voltage applied to the H _B, As exemplified by reference numeral 34 in FIG. 7, the difference in brightness due to the apparent voltage difference between the auxiliary capacitance electrodes can be suppressed.

Further, in the control in the PC mode process, the light / dark difference due to the voltage difference of the auxiliary capacitance reference electrode between the sub-pixels is slightly suppressed as compared with the above process. While suppressing the appearance of the contrast between sub-pixels, it is possible to eliminate the decrease in contrast at a wide viewing angle, that is, to improve the contrast when viewed from an oblique direction. Such control is suitable for PCs that are often used alone, that is, for still image specifications. Also for this control, the voltage applied to the auxiliary capacitance reference electrodes H _A and H _B is switched for each frame or for each field (for each unit of screen data input to the liquid crystal display panel 8). Thus, as illustrated by reference numeral 34 in FIG. 7, it is possible to suppress the difference in brightness due to the apparent voltage difference between the auxiliary capacitance electrodes.

  FIG. 8 is a diagram for comparing the case where the γ characteristic correction processing described in FIGS. 1 to 7 is performed with the case where the γ characteristic correction processing is not performed. FIG. FIG. 8B is a graph for explaining the variation of the luminance ratio for each gradation depending on the viewing angle when the γ characteristic correction is performed in the broadcast mode and the cinema mode, and FIG. It is a graph for demonstrating the fluctuation | variation by the viewing angle of the luminance ratio for every gradation at the time of performing a difference emphasis process (same mode) with (gamma) characteristic correction by this invention. In FIG. 8, the solid line indicates 0 ° (front view), the broken line indicates ± 45 °, and the dotted line indicates ± 60 °.

  As shown in FIG. 8A, when only the sub-pixel voltage difference enhancement process is performed, a voltage (auxiliary capacitance component voltage) other than the gradation voltage is added to each sub-pixel. It can be seen that the characteristic draws a curve away from the ideal curve (ideal γ curve (γ = 2.2 to 2.4)). On the other hand, when a process combining the inter-subpixel voltage difference enhancement process and the γ characteristic correction process is performed, the ideal is obtained in any of 0 °, ± 45 °, and ± 60 ° in FIG. 8B. As can be seen from the fact that the γ curve is approaching, the ideal γ characteristic is achieved against the deviation of the γ characteristic that occurs as a result of correcting the gradation voltage for each subpixel to improve the viewing angle. It becomes possible to correct, and to provide a γ characteristic suitable for each mode. According to the present embodiment, the gradation due to the change in the gradation characteristic (γ characteristic) (particularly the change in the halftone is remarkable) that can be caused by optimizing the voltage ratio between the sub-pixels in order to improve the viewing angle characteristic. It is possible to eliminate the floating or sinking phenomenon of the tonal characteristics.

  As described above, according to the present embodiment, in a multi-pixel driving type liquid crystal display device, an appropriate viewing angle is selected according to video information such as a result of detecting a type of video to be selected by the user or displayed on the main body. Characteristics and gradation characteristics can be provided, and in particular, it is possible to eliminate the whitening phenomenon caused by the change in gradation characteristics when viewed obliquely from the front view that occurs when using liquid crystal such as the vertical alignment mode. It is also possible to automatically provide gradation characteristics in accordance with the image information that has been obtained, elimination of contrast differences between sub-pixels, and high contrast characteristics in the normally black mode. As a main effect of the present invention, at the same time as this effect, it is possible to provide appropriate gradation characteristics for each video information by correcting the gradation characteristics of the unit pixels disturbed by this adjustment processing. That is, the floating of the gradation characteristic due to the change of the gradation characteristic (γ characteristic) (particularly the change of the halftone is remarkable) caused by optimizing the voltage ratio between the sub-pixels in order to improve the viewing angle characteristic, Or it becomes possible to eliminate a sinking phenomenon. Further, by providing the auxiliary capacitance reference electrode as described above, it is not necessary to provide a source electrode line for each sub-pixel or to perform gradation conversion of the source voltage for each sub-pixel, and the above-described effect can be obtained. .

  Next, another embodiment capable of executing γ characteristic correction will be described. In the description of the γ characteristic correction described here, the embodiment described with reference to FIGS. 1 to 8 (display control based on display mode selection by the user) is performed. However, other embodiments may be used. The same applies. Further, in this embodiment, for the sake of simplification of description, a description will be given centering on portions that are different from the embodiment described with reference to FIGS.

  FIG. 9 is a block diagram showing an example of the configuration of a liquid crystal display device according to another embodiment of the present invention, in which 40 is a γ characteristic correction unit, 40a is a gradation conversion unit, and 40b is a gradation conversion unit 40a. ROM, 41 is a video signal input unit, 42 is a user operation unit, 43 is a microcomputer, 44 is a controller, 45 is a source driver, 46 is ROM, 47 is an auxiliary capacitance signal generation circuit, 48 is a liquid crystal display panel, and 49 is It is a gate driver.

  The liquid crystal display device according to this embodiment is the same as the liquid crystal display device according to the embodiment described with reference to FIGS. 1 to 8, but includes other γ characteristic correction means (gradation characteristic correction means). This γ characteristic correction means is a means for supplementing the process of adjusting the voltage value supplied by the voltage supply means according to the video information in the adjustment means for each sub-pixel, and is a unit changed by the adjustment process in the adjustment means. This is a means for correcting the gradation characteristics of the pixel. The present embodiment includes a γ characteristic correction unit 40 (which may be included in the controller 44) having a gradation conversion unit 40a and a ROM 40b for the gradation conversion unit 40a as the γ characteristic correction unit. It is assumed that the potential difference is adjusted by, for example, color discrimination of the display image so that the gradation data can be changed. Other processing is as described above, and the description is simplified.

  Moreover, the control means in this embodiment is illustrated by the microcomputer 43 which sends the control signal according to the mode selection operation received in the user operation part 42 to the controller 44 and the gradation conversion part 40a. The operation accepting unit is exemplified by the user operation unit 42 as in the above-described embodiment. The video signal input unit 41 is the same as that of the above-described embodiment, including a remote control including a power button 42a, a menu button 42b, a direction instruction and determination key 42c, a channel selection and position key 42d, and the like.

  The microcomputer 43 issues a command to the controller 44 based on the display mode selection result from the user operation unit 42 to control the controller 44, and also displays the display mode for the γ characteristic correction unit 40 (gradation conversion unit 40 a). Control is performed by issuing a command based on the selection result. The controller 45 controls the storage capacitor signal generation circuit 47 in addition to the control of the source driver 45 and the gate driver 49, so that video information to be displayed on the liquid crystal display panel 48 (that is, input by the video signal input unit 41). Display control of the liquid crystal display panel 48 according to the display mode selection result in the user operation unit 42. Further, as described above, the controller 44 includes, for example, a drive voltage generation unit, a drive signal generation unit, and a LUT (Look Up Table) (not shown). Further, the source driver 45, the gate driver 49, and the auxiliary capacitance signal generation circuit 47 are also as described above, and the liquid crystal display panel 48 is as described together with the equivalent circuit of FIG.

  In the gradation converting unit 40a, a correction value is assigned in advance to the number of gradations from 0 to 255, and the correction result of the video information (image data) based on the correction value is output to the controller 44. That is, in order to correct the low gradation γ characteristic, a different gradation value is provided for each gradation in the ROM 40b for the gradation converting unit 40a. This method also makes it possible to correct an ideal γ characteristic for a video signal to which a predetermined voltage has been added once. Next, a processing example in the γ characteristic correction unit as a feature of the present embodiment will be described in detail.

  FIG. 10 is a diagram for explaining an example of the γ correction process in the liquid crystal display device of FIG. 9. In FIG. 10, reference numeral 40 c denotes a correction by the gradation correction data used for the γ correction process (correction by the γ table). It is a table | surface which shows the example of the three gradation correction data with respect to the input gradation as an example.

  As shown in Table 40c, gradation correction data 1, gradation correction data 2, and gradation correction data 3 are stored in the ROM 40b for the input gradation. For example, the gradation correction data 1 is an example of output gradation data that is applied when the potential difference of the voltage applied to the reference electrode of the auxiliary capacitor is small with respect to the input gradation data. 0, 1, 2, 3, 4,. . . , 50, 51, 52,. . . , 255 for the input gradation data of 0, 2, 4, 6, 8,. . . 70, 71, 72,. . . , 255 output gradation data is prepared.

  The gradation correction data 2 is an example of output gradation data that is applied when the potential difference of the voltage applied to the reference electrode of the auxiliary capacitor is medium with respect to the input gradation data. 0, 1, 2, 3, 4,. . . , 50, 51, 52,. . . , 255 for the input gradation data of 0, 1, 3, 5, 7,. . . 60, 61, 62,. . . , 255 output gradation data is prepared. The gradation correction data 3 is an example of output gradation data applied when the potential difference of the voltage applied to the reference electrode of the auxiliary capacitor is larger than the input gradation data. 0, 1, 2, 3, 4,. . . , 50, 51, 52,. . . , 255 for the input gradation data, 0, 1, 2, 3, 4,. . . , 50, 51, 52,. . . , 255 output gradation data is prepared.

  The gradation conversion unit 40a selects gradation correction data corresponding to the control signal from the ROM 40b based on the control signal output from the microcomputer 43 (control signal corresponding to the mode selection operation received by the user operation unit 42). And output to the controller 44. For example, when a control signal is sent by a potential difference such as potential difference 1, potential difference 2, potential difference 3 as the control level of the microcomputer 43, gradation correction data 1, gradation correction data 2, gradation correction data corresponding to each potential difference. 3 is read from the ROM 40 b and output to the controller 44.

In the liquid crystal display device according to the present embodiment, control is started when the display mode is selected by the user, as in the control flow of FIG. In the control flow of FIG. 6, the γ characteristic correction processing according to the present embodiment is not the auxiliary capacitance reference electrode control data and the gradation reference voltage control data but the auxiliary capacitance reference electrode control data when reading the data for each mode. In addition, the gradation correction control data is read, and the data is output. Further, one frame or every each field of each other auxiliary capacitor reference electrode H _A (crystal units each screen data to be input to the display panel _48), switches the applied voltage to the H _B auxiliary capacitor reference electrode control data and The form in which the gradation correction control data is output can be similarly applied, and control may be performed so as to suppress the light / dark difference due to the voltage difference of the auxiliary capacitance electrode. Also in the γ characteristic correction processing according to the present embodiment, as illustrated in FIG. 8, the ideal γ curve is approached in any case of 0 °, ± 45 °, and ± 60 °.

  Further, as an embodiment capable of performing the γ characteristic correction according to the present invention, the embodiment described with reference to FIGS. 1 to 8 and the embodiment described with reference to FIGS. 9 and 10 may be combined. Such an embodiment will be briefly described. The details can be understood by referring to the original embodiment.

  FIG. 11 is a block diagram showing a configuration example of a liquid crystal display device according to another embodiment of the present invention, in which 50 is a γ characteristic correction unit, 50a is a gradation conversion unit, and 50b is a gradation conversion unit 50a. ROM, 50c is a reference gradation voltage generating unit, 50d is a ROM for the reference gradation voltage generating unit 50c, 51 is a video signal input unit, 52 is a user operation unit, 53 is a microcomputer, 54 is a controller, and 55 is a source. A driver 56 is a ROM, 57 is an auxiliary capacitance signal generating circuit, 58 is a liquid crystal display panel, and 59 is a gate driver.

  The liquid crystal display device according to the present embodiment includes, as a γ characteristic correcting unit, a γ characteristic correcting unit 50 (controller 54) including a gradation converting unit 50a and a ROM 50b for the gradation converting unit 50a, and a reference gradation voltage generating unit 50c and a ROM 50d for the reference gradation voltage generating unit 50c. It is assumed that the γ characteristic correction unit 50 is configured to be able to change the reference gradation voltage and gradation data. Other processing is as described above, and the description is simplified.

  The control means in the present embodiment is exemplified by the microcomputer 53 that sends a control signal corresponding to the mode selection operation received by the user operation unit 52 to the controller 54, the gradation conversion unit 50a, and the reference gradation voltage generation unit 50c. To do. The operation accepting unit is exemplified by the user operation unit 52 as in the above-described embodiment. The video signal input unit 51 is the same as that of the above-described embodiment, including a remote control including a power button 52a, a menu button 52b, a direction instruction and determination key 52c, a channel selection and position key 52d, and the like.

The microcomputer 53 issues a command to the controller 54 based on the display mode selection result from the user operation unit 52 to control the controller 54, and the γ characteristic correction unit 50 (the gradation conversion unit 50 a and the reference gradation voltage generation unit). 50c) is also controlled by issuing a command based on the display mode selection result. The controller 55 controls the storage capacitor signal generation circuit 57 in addition to the control of the source driver 55 and the gate driver 59, so that video information to be displayed on the liquid crystal display panel 58 (that is, input by the video signal input unit 51). Display control of the liquid crystal display panel 58 according to the display mode selection result in the user operation unit 52.
Further, as illustrated, the controller 54 includes a drive voltage generation unit, a drive signal generation unit, and a LUT (Look Up Table) (not shown). Further, the source driver 55, the gate driver 59, and the auxiliary capacitance signal generation circuit 57 are also as described above, and the liquid crystal display panel 58 is as described together with the equivalent circuit of FIG.

  The gradation conversion unit 50a selects gradation correction data corresponding to the control signal from the ROM 50b based on the control signal output from the microcomputer 53 (control signal corresponding to the mode selection operation received by the user operation unit 52). And output to the controller 54. For example, when a control signal is sent by a potential difference such as potential difference 1, potential difference 2, potential difference 3 as the control level of the microcomputer 53, gradation correction data 1, gradation correction data 2, gradation correction data corresponding to each potential difference. 3 is read from the ROM 50 a and output to the controller 54.

  Based on the control signal output from the microcomputer 53 (control signal corresponding to the mode selection operation received by the user operation unit 52), the reference gradation voltage generation unit 50c receives reference gradation data corresponding to the control signal from the ROM 50d. Is output to the source driver 55. For example, when a control signal is sent by a potential difference such as potential difference 1, potential difference 2, potential difference 3 as the control level of the microcomputer 53, reference gradation data 1, reference gradation data 2, reference gradation data corresponding to each potential difference is sent. 3 is read from the ROM 50 d and output to the source driver 55.

In the liquid crystal display device according to the present embodiment, control is started when the display mode is selected by the user, as in the control flow of FIG. In the control flow of FIG. 6, the γ characteristic correction process according to the present embodiment is not limited to the auxiliary capacitance reference electrode control data and the gradation reference voltage control data, but also the gradation correction control data when reading the data for each mode. Is also read and the data is output. Further, one frame or every one field per assisted (liquid crystal display screen for each unit of data to be input to the panel 58) of mutual capacitance reference electrode H _A, switches the applied voltage to the H _B, auxiliary capacitor reference electrode control data Similarly, the output processing of the gradation reference voltage control data and the gradation correction control data can be applied in the same manner, and control may be performed so as to suppress the light / dark difference due to the voltage difference of the auxiliary capacitance electrode. Also in the γ characteristic correction processing according to the present embodiment, as illustrated in FIG. 8, the ideal γ curve is approached in any case of 0 °, ± 45 °, and ± 60 °.

  Further, in the embodiment described with reference to FIGS. 1 to 11, the type of display mode described above is set to an image type (video type) indicating whether the video information to be displayed is a still image or a moving image. Display control according to still images / moving images can be performed. This display control is control in which a predetermined value of voltage supplied to each sub-pixel is individually assigned according to the image type. Further, when the display mode is selected by the user, for example, the display mode for performing the sub-pixel voltage difference emphasis process is selected by the user, so that the input video information input by the video signal input unit automatically becomes a moving image. In addition, the input source may be automatically switched.

  Display control according to still images / moving images eliminates white-blowing phenomenon caused by changes in tone characteristics when viewed from the front, especially when using liquid crystal in the vertical alignment mode, etc. As a result of user operation, it is possible to improve the white floating phenomenon required at the time of display, eliminate the difference in shade between sub-pixels required at the time of still image display, and provide high contrast characteristics in normally black mode, etc. It is possible to provide a video display state corresponding to the selected mode.

  Further, as another example of the type of display mode described above, by adopting a signal type indicating whether the video information to be displayed is a television signal or an RGB signal, it corresponds to the television signal / RGB signal. Display control is possible. This display control is control in which a predetermined value of voltage supplied to each sub-pixel is individually assigned according to this signal type. Note that RGB signals and television signals generally correspond to still image signals and moving image signals, respectively. However, for example, a moving image as a continuation of still images may be viewed. In addition, when the user selects a display mode (display mode for displaying a television broadcast) for performing, for example, a sub-pixel voltage difference emphasis process by the selection of the display mode by the user, the input video input by the video signal input unit The input source may be automatically switched so that the information automatically becomes a television signal.

  The display control according to the television signal / RGB signal eliminates the whitening phenomenon caused by the change in gradation characteristics when viewed from an oblique direction with respect to the front view, particularly when using a liquid crystal such as a vertical alignment mode, and It is possible to improve the white-blowing phenomenon required at the time of television broadcast signal, eliminate the difference in shade between sub-pixels required at the time of PC screen selection, and provide high contrast characteristics in normally black mode, etc. As a result of the operation, it is possible to provide a video display state corresponding to the selected mode.

  As another embodiment, in the liquid crystal display device according to each embodiment described with reference to FIGS. 1 to 11, a selection operation for selecting video information to be displayed is selected instead of the user selection of the display mode. In addition, an operation receiving means for receiving from the user may be provided. Therefore, the operation accepting unit in the present embodiment accepts a selection operation related to display control, and this selection operation corresponds to an operation such as a channel operation for selecting video information output on the screen by the user's operation. . Then, the adjusting unit adjusts the voltage value supplied by the voltage supplying unit individually for each sub-pixel according to the type of the video information selected by the operation receiving unit. For example, in the ROM for the auxiliary capacitance signal generation circuit, the voltage value to be sent to each auxiliary capacitance reference electrode corresponding to the type of video information is stored, and the user selects the video information to be viewed. Control is started. Then, as the types of video information to be selected, display modes corresponding to the types may be a theater mode (for example, corresponding to video information of high-definition broadcast), a PC mode, and a normal broadcast mode. For other processes, the description in FIGS. 1 to 11 may be used, and the description thereof is omitted.

  Furthermore, as another embodiment, in the liquid crystal display device according to each embodiment described with reference to FIGS. 1 to 11, a source for switching an input source of video information to be displayed instead of a user selection of a display mode A switching means may be provided. Then, the adjusting means adjusts the voltage value supplied by the voltage supplying means for each subpixel according to the type of the input source selected by the switching by the source switching means. For example, in the ROM for the auxiliary capacitance signal generating circuit, the voltage value to be sent to each auxiliary capacitance reference electrode corresponding to the input source is stored, and the control is started by the user selecting the input source. Is done. As the type of the input source to be selected, the display mode corresponding to the type may be a theater mode (for example, corresponding to video information of high-definition broadcast), a PC mode, and a normal broadcast mode. For other processes, the description in FIGS. 1 to 11 may be used, and the description thereof is omitted.

  Furthermore, as another embodiment, in the liquid crystal display device according to each embodiment described with reference to FIGS. 1 to 11, instead of selecting a display mode for video information to be displayed, an input signal discrimination process is performed. You may make it provide the input signal determination part to perform. Then, the adjusting means adjusts the voltage value supplied by the voltage supplying means for each sub-pixel according to the result of the determination process.

  The input signal determination unit determines the type of the image signal input by the video signal input unit, and transmits the determination result to the microcomputer. The discrimination executed here is, for example, discrimination based on motion / still image motion detection or video information format, or discrimination of RGB signals / television signals (or whether they are high-definition television signals, etc.). By this determination, a voltage value applied to an auxiliary capacitor described later is determined. The ROM for the auxiliary capacitance signal generation circuit may store the voltage value to be sent to each auxiliary capacitance reference electrode according to the signal type or the operation mode. Other processes are as described with reference to FIGS. 1 to 11, and the description thereof will be simplified.

Next, the voltage applied to the auxiliary capacitance reference electrodes H _A and H _B is described for each frame or for each field (each unit of screen data input to the liquid crystal display panel) described in each of the above-described embodiments. A supplementary description will be given of a mode in which control data such as auxiliary capacitance reference electrode control data is output by switching.

  FIG. 12 is a diagram for explaining in detail a control example in the normal broadcast mode and the cinema mode as a control example of the liquid crystal display device according to the present invention, and FIG. 12A is a frame of the auxiliary capacitance electrode with respect to the vertical synchronization signal. FIG. 12B is a timing chart for explaining the control for each frame and the control for each frame of the gradation voltage with respect to the horizontal synchronization signal and the voltage applied to each sub-pixel. FIG. 12B is a control example for frame (n). FIG. 12C is a diagram for explaining the brightness of each subpixel, and FIG. 12C is a diagram for explaining the control example based on the brightness of each subpixel for frame (n + 1).

The upper left red subpixel Ra and the paired subpixel Rb in FIGS. 12B and 12C will be described. For the frame (n), at the same time as the vertical synchronization signal Vsync, the auxiliary capacitance electrode _{HA is used.} to the voltage Vlca applied, an auxiliary capacitor electrode _{H B} voltage Vlcb applied to, their voltage values V1, V2 is, by switching to frame (n + 1), is switched to the reverse. On the other hand, the grayscale voltage Vsig is sent to the source line simultaneously with the horizontal synchronization signal (gate pulse) Hsync for the frame (n), and the horizontal synchronization is also performed for the frame (n + 1) when switching from the frame (n). Simultaneously with the signal (gate pulse) Hsync, the gradation voltage Vsig is sent to the source line.

For the frame (n), simultaneously with the horizontal synchronization signal Hsync, the voltage to the auxiliary capacitance electrode _HA in addition to the gradation voltage Vsig is added to the source line for the subpixel Ra, and Vsig is applied to the subpixel Ra. −Vlca = Vsig−V1 is applied. When shifting to the frame (n + 1), simultaneously with the horizontal synchronization signal Hsync, the voltage applied to the subpixel Ra is switched to Vsig−Vlca = Vsig−V2. As a result, the sub-pixel Ra becomes bright in the frame (n) as shown in FIG. 12B and dark in the frame (n + 1) as shown in FIG. On the other hand, for the sub-pixel Rb, relative to the frame (n), the voltage of the storage capacitor electrode _{H B} in addition to gray scale voltage Vsig to the horizontal synchronizing signal Hsync simultaneously source lines are added, Vsig-Vlcb = Vsig- V2 is applied. When shifting to the frame (n + 1), simultaneously with the horizontal synchronization signal Hsync, the voltage applied to the sub-pixel Rb is switched to Vsig−Vlca = Vsig−V1. As a result, the sub-pixel Rb is dark in the frame (n) as shown in FIG. 12B and bright in the frame (n + 1) as shown in FIG. In this way, by switching the voltage applied to each auxiliary capacitance electrode for each frame or field, as shown by reference numeral 34 in FIG. 7, it is possible to suppress the difference in brightness due to the apparent voltage difference between the auxiliary capacitance electrodes. it can. In the control in the normal broadcast mode and the cinema mode, such a switching is particularly preferable because the difference in brightness due to the voltage difference of the auxiliary capacitance electrode between the sub-pixels is more likely to occur.

  FIG. 13 is a diagram for explaining in detail a control example in the PC mode as a control example of the liquid crystal display device according to the present invention. FIG. 13A is a control for each frame of the auxiliary capacitance electrode with respect to the vertical synchronization signal. FIG. 13B is a timing chart for explaining frame-by-frame control of the gradation voltage with respect to the horizontal synchronization signal and the voltage applied to each sub-pixel. FIG. 13B is a control example of each sub-pixel for frame (n). FIG. 13C is a diagram for explaining the brightness and darkness, and FIG. 13C is a diagram for explaining the control example based on the brightness of each sub-pixel for the frame (n + 1).

The upper left red sub-pixel Ra and the sub-pixel Rb paired with the red sub-pixel Ra in FIGS. 13B and 13C will be described. For the frame (n), the auxiliary capacitance electrode _{HA is} simultaneously used with the vertical synchronization signal Vsync. the voltage Vlca is applied, a voltage Vlcb applied to the auxiliary capacitance electrode _{H B,} their voltage values V1pc (<V1), V2pc ( <V2) is, by switching to frame (n + 1), is switched to the reverse. On the other hand, the grayscale voltage Vsig is sent to the source line simultaneously with the horizontal synchronization signal (gate pulse) Hsync for the frame (n), and the horizontal synchronization is also performed for the frame (n + 1) when switching from the frame (n). Simultaneously with the signal (gate pulse) Hsync, the gradation voltage Vsig is sent to the source line.

For the frame (n), simultaneously with the horizontal synchronization signal Hsync, the voltage to the auxiliary capacitance electrode _HA in addition to the gradation voltage Vsig is added to the source line for the subpixel Ra, and Vsig is applied to the subpixel Ra. −Vlca = Vsig−V1pc is applied. When shifting to the frame (n + 1), simultaneously with the horizontal synchronization signal Hsync, the voltage applied to the sub-pixel Ra is switched to Vsig−Vlca = Vsig−V2pc. As a result, the sub-pixel Ra becomes bright in the frame (n) as shown in FIG. 13B and dark in the frame (n + 1) as shown in FIG. On the other hand, for the sub-pixel Rb, relative to the frame (n), the voltage of the storage capacitor electrode _{H B} in addition to gray scale voltage Vsig to the horizontal synchronizing signal Hsync simultaneously source lines are added, Vsig-Vlcb = Vsig- V2pc is applied. When shifting to the frame (n + 1), simultaneously with the horizontal synchronization signal Hsync, the voltage applied to the sub-pixel Rb is switched to Vsig−Vlca = Vsig−V1pc. As a result, the sub-pixel Rb is dark in the frame (n) as shown in FIG. 13B and bright in the frame (n + 1) as shown in FIG. 13C. In this way, by switching the voltage applied to each auxiliary capacitance electrode for each frame or field, as shown by reference numeral 34 in FIG. 7, it is possible to suppress the difference in brightness due to the apparent voltage difference between the auxiliary capacitance electrodes. it can. Even in the control in the PC mode, such a switching is preferable because there is a light / dark difference due to the voltage difference of the auxiliary capacitance electrode between the sub-pixels.

  In the embodiments of the present invention, the voltage applied to the auxiliary capacitance electrode is described as a DC voltage, but the data voltage (voltage applied from the source electrode) is driven by line inversion, frame inversion, or dot inversion driving. In this case, since the effective value of the voltage applied to the auxiliary capacitor also acts, the voltage applied to the auxiliary capacitor reference voltage is applied with a voltage whose polarity is inverted with respect to the reference voltage of the liquid crystal layer. Also good.

It is a block diagram which shows one structural example of the liquid crystal display device which concerns on one Embodiment of this invention. It is a figure which shows an example of the equivalent circuit of the liquid crystal display panel in the liquid crystal display device of FIG. It is a figure for demonstrating an example of the (gamma) correction process in the liquid crystal display device of FIG. FIG. 2 is a diagram illustrating an example of a gradation voltage generation unit in a source driver corresponding to a reference gradation voltage generation unit in the liquid crystal display device of FIG. 1. FIG. 2 is a diagram illustrating an example of a main part of a reference gradation voltage generation unit in the liquid crystal display device of FIG. 1. It is a flowchart for demonstrating the example of control in the liquid crystal display device of FIG. It is a figure for comparing the voltage difference emphasis process between the sub-pixels by this invention with a prior art example. FIG. 8 is a diagram for comparing the case where the γ characteristic correction processing described with reference to FIGS. 1 to 7 is performed and the case where it is not. It is a block diagram which shows one structural example of the liquid crystal display device which concerns on other embodiment of this invention. It is a figure for demonstrating an example of the (gamma) correction process in the liquid crystal display device of FIG. It is a block diagram which shows one structural example of the liquid crystal display device which concerns on other embodiment of this invention. It is a figure for demonstrating in detail the control example in normal broadcast mode and cinema mode as a control example of the liquid crystal display device which concerns on this invention. It is a figure for demonstrating in detail the example of control in PC mode as an example of control of the liquid crystal display device which concerns on this invention.

Explanation of symbols

1, 41, 51 ... Video signal input unit, 2, 42, 52 ... User operation unit, 3, 43, 53 ... Microcomputer (microcomputer), 4, 44, 54 ... Controller, 5, 45, 55 ... Source driver, 6, 10b, 40b, 46, 50b, 50d, 56 ... ROM, 7, 47, 57 ... Auxiliary capacitance signal generation circuit, 8, 48, 58 ... Liquid crystal display panel, 9, 49, 59 ... Gate drivers, 10, 40 , 50... Gamma characteristic correction unit, 10a, 50c, reference gradation voltage generation unit, 40a, 50a, gradation conversion unit.

Claims (2)

  A liquid crystal display panel having a plurality of unit pixels connected to a source electrode and a gate electrode and having a plurality of subpixels in each unit pixel and capable of gradation display, and depending on video information to be displayed, A gradation voltage supplied from the source electrode to each of a plurality of sub-pixels configured in the unit pixel, the liquid crystal display device including a control unit that performs display control of video information in the liquid crystal display panel In addition, a voltage supply unit that individually supplies a voltage having a predetermined voltage value is provided, and the control unit adjusts the voltage value supplied by the voltage supply unit individually for each sub-pixel according to the video information. A liquid crystal display device comprising: an adjusting unit; and a tone characteristic correcting unit that corrects a tone characteristic of a unit pixel changed by the adjusting process of the adjusting unit.   2. The liquid crystal display device according to claim 1, wherein the voltage supply unit includes an auxiliary capacitance reference electrode in which each sub-pixel in the unit pixel is separately connected, and the voltage value is supplied from each auxiliary capacitance reference electrode. A liquid crystal display device, wherein the liquid crystal display device is supplied for each sub-pixel.

Images