JP2008096927A - Liquid crystal display device, driving method of liquid crystal display device, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem in the conventional liquid crystal display device, wherein dimming is performed by changing a lighting ratio of a light source of a backlight and the light source of the backlight is lighted when starting to write the voltage corresponding to display data into the display element of a pixel, thereby degrading the contrast. <P>SOLUTION: The device includes a source driver which applies the application voltage corresponding to the data for display to a signal line of a liquid crystal display panel, a backlight 11 to be intermittently turned on and illuminate the liquid crystal display panel, and a backlight controller 19 which determines at least one of the lighting start time relating to the prescribed lighting period of the backlight 11, the lighting end time and the mid-time of the prescribed lighting period based on the voltage that the application voltage is written into the liquid crystal display element via the signal line. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device provided with a backlight that illuminates a liquid crystal display panel that can be intermittently lit, a driving method of the liquid crystal display device, a program, and a recording medium.

  Liquid crystal display devices are thin and lightweight, and their use has been expanded in recent years as an alternative to conventional cathode ray tubes. However, currently widely used TN (Twisted Nematic) alignment liquid crystal display panels have a narrow viewing angle, a slow response speed, and appear to have a tail when moving images are displayed.

  On the other hand, in recent years, a liquid crystal display device including a display element in an OCB (Optically Compensated Birefringence) mode having characteristics of a high-speed response and a high viewing angle has been used. In this liquid crystal display device, a liquid crystal is bent to perform visual compensation, and an optical phase compensation film is combined with this to obtain a wide viewing angle.

  FIG. 15 is a cross-sectional view schematically illustrating an alignment state of liquid crystal molecules included in the OCB mode display element. 15A and 15B are cross-sectional views showing a voltage application state, and FIG. 15C is a cross-sectional view showing a voltage non-application state.

  Nematic liquid crystal is injected between the glass substrates 61 of the liquid crystal display panel constituting the liquid crystal display device using the OCB mode display element as shown as liquid crystal molecules 62 in FIG. The alignment state of the liquid crystal to which no voltage is applied is called a splay state 63. When a power supply of a liquid crystal display device using an OCB mode display element is turned on, it is necessary to perform driving called transfer driving. That is, the transfer driving means that a relatively large voltage of about 20 to 25 volts is applied to the liquid crystal layer when the liquid crystal display device is turned on to change from the splay state 63 shown in FIG. ), And driving to shift to the bend states 64a and 64b shown in FIG. The display using the bend states 64a and 64b is a characteristic of the liquid crystal display device using the OCB mode display element. The liquid crystal display device using the OCB mode display element bends depending on the voltage level. The transmittance of the panel is changed by changing the state.

  A bend state 64a shown in FIG. 15A indicates a bend state when white is displayed, and a bend state 64b shown in FIG. 15B indicates a bend state when black is displayed. .

  Further, in a liquid crystal display device using an OCB mode display element, when a voltage of 2 volts or less is continuously applied to the liquid crystal display panel, the alignment state of the liquid crystal gradually transitions from the bend states 64a and 64b to the splay state 63. (Hereinafter this transition is called reverse transition). In order to prevent such reverse transition, driving called reverse transition prevention driving is performed in a liquid crystal display device using an OCB mode display element.

  That is, in the case of a normally white mode liquid crystal display device that performs white display when a relatively low voltage is applied and performs black display when a relatively high voltage is applied, reverse transition prevention drive is In this drive, reverse transition is prevented by applying a voltage corresponding to black separately from a voltage corresponding to a video signal periodically displayed on each pixel. The reverse transition prevention drive is called double speed conversion in which an operation of applying a voltage corresponding to black to a pixel and an operation of applying a voltage corresponding to a video signal to the pixel are alternately performed to prevent reverse transition. There is a reverse transition prevention drive (see, for example, Patent Document 1). Hereinafter, this double speed conversion is referred to as black insertion driving.

  Therefore, in a liquid crystal display device using a conventional OCB mode display element, in a period for displaying one frame (or one field) video, a display period in which a voltage corresponding to a video signal is applied to the pixels, In order to prevent reverse transition, a black insertion period in which a voltage corresponding to black is applied to the pixel is provided.

  By using the black insertion drive described above and extending the black insertion period, the display of the liquid crystal display device using the OCB mode display element can be brought close to an impulse-type display such as a CRT. Video visibility can be improved. This is because high-speed response, which is an advantage of the OCB mode display element, can be used. Further, by using the black insertion drive, not only the moving image visibility is improved, but also high contrast display can be performed.

  In addition, in the TN (Twisted Nematic) alignment liquid crystal display panel that is widely used at present, the double speed conversion described above may be used in order to improve moving image visibility. The driving of the liquid crystal display device in such a case is also referred to as black insertion driving.

  Furthermore, in recent years, with the spread of backlights using LEDs and the improvement in the high-speed response of cold cathode fluorescent lamps, backlights that drive the backlights in conjunction with driving of the liquid crystal display panel by a source driver or the like have been developed. Drive systems are also being implemented.

  Recently, a field sequential color liquid crystal display device has been developed (see, for example, Patent Document 2).

  The field sequential color liquid crystal display device is a liquid crystal display device that sequentially displays images of three primary colors (R, G, B) with one pixel without providing a color filter for each pixel. Compared to the apparatus, it has advantages such as high transmittance and high resolution.

  Therefore, if an OCB mode display element is used, black insertion drive is performed, and a field sequential color system is adopted, an impulse-type display such as a CRT can be realized, and a high transmittance, high resolution, and high contrast liquid crystal can be realized. A display device can be realized.

  FIG. 16 is a block diagram of a conventional liquid crystal display device 101 that performs black insertion driving by a conventional field sequential color system and that drives a backlight in conjunction with driving of a liquid crystal display panel by a source driver or the like.

  The liquid crystal display device 101 includes a liquid crystal display panel 10, a backlight 111, a source driver 2, a gate driver 3, a controller 4, a frame memory 22, an input power supply 16, a liquid crystal driving voltage generation circuit 17, a light control unit 118, and a backlight control unit. 119 and an optical sensor unit 126.

  The liquid crystal display panel 10 is an active matrix liquid crystal display panel. That is, in the liquid crystal display panel 10, the signal lines and the scanning lines are arranged in a matrix on the array substrate, and a pixel is formed at each intersection thereof. Each pixel has a switching element, a storage capacitor, and a display element. Further, the display element includes a pixel electrode, a counter electrode, a liquid crystal layer sandwiched between the pixel electrode and the counter electrode, and the like. An OCB mode liquid crystal is used as the liquid crystal layer. Further, since the liquid crystal display device 101 is a field sequential method, red, green, and blue color filters are not formed on the counter substrate of the liquid crystal display panel 10.

  The backlight 111 is disposed on the back surface of the liquid crystal display panel 10, and emits light of R (Red), G (Green), and B (Blue) colors that are light sources, and light emitted from the LEDs. A light guide plate or the like for guiding the light to the liquid crystal display panel 10 is provided.

  The backlight 111 is provided with an optical sensor unit 126 that detects the luminance of each color of R, G, and B.

  The input power supply 16 supplies power to the backlight 111, the controller 4, the liquid crystal drive voltage generation circuit 17, the dimmer 118, and the like.

  The liquid crystal drive voltage generation circuit 17 is a circuit that adjusts the voltage supplied to the source driver 2 and the gate driver 3.

  The gate driver 3 is a circuit that supplies a gate signal to the scanning lines of the liquid crystal display panel 10.

  The source driver 2 supplies a voltage corresponding to each color of the display signal during the display period of each color (R, G, B) in the display period, and supplies a voltage corresponding to black during the black insertion period to the liquid crystal display panel. 10 is a circuit for supplying 10 signal lines.

  The controller 4 includes a signal processing unit 21 and a timing control unit 23, and the source driver 2 includes a D / A conversion unit 24 and a shift register 25.

  Based on the luminance of each color (R, G, B) of the backlight 111 detected by the light sensor unit 126, the light control unit 118 determines the lighting period of the LED of each color (R, G, B) of the backlight 111. The circuit adjusts the luminance and / or chromaticity of the backlight by adjusting the ratio of each color to the display period (red display period, green display period, blue display period).

  Hereinafter, the ratio of the lighting period of each color LED to the display period of each color will be referred to as the lighting ratio of that color.

  The timing control unit 23 controls the timing for operating the gate driver 3 and the timing for sending an image signal to the source driver 2, and links the lighting of the backlight 111 to the driving of the liquid crystal display panel 10 by the source driver 2 or the like. This is a circuit for sending a backlight control signal, which is a signal for this purpose, to the backlight control unit 119.

  The backlight control unit 119 controls turning on / off of the backlight 111 in accordance with the backlight control signal sent from the timing control unit 23.

  The frame memory 22 is a memory for storing a video signal for one screen.

  Next, the operation of the conventional liquid crystal display device 101 will be described.

  When the power of the liquid crystal display device 101 is turned on, the liquid crystal layer of the liquid crystal display panel 10 remains in the splay state 63 as shown in FIG. 15C, so that the bend state 64a in FIG. It is also necessary to transition to the bend state 64b in FIG. Therefore, when the power of the liquid crystal display device 101 is turned on, the liquid crystal display device 101 performs transition driving in order to transition the liquid crystal layer from the splay state to the bend state. That is, the source driver 2 uses the voltage for transfer driving so that the voltage between the pixel electrode and the counter electrode is higher than the voltage for displaying an image of 20 to 25 volts for a predetermined time. As a result, a voltage of 20 to 25 volts is applied to the signal line. Accordingly, a voltage for driving the transition is applied to the liquid crystal layer for a predetermined time, so that the liquid crystal layer of the liquid crystal display panel 10 transitions from the splay state to the bend state, and the display operation of the liquid crystal display device 101 is possible. It becomes.

  When the transfer driving is completed as described above and the display operation is enabled, the liquid crystal display device 101 starts the display operation.

  When the video signal, which is RGB data, is stored in the frame memory 22 for one screen, the signal processing unit 21 performs gradation correction and gamma correction processing on the video signal read from the frame memory 22 and displays the video signal. After conversion to red data, black data for black insertion drive, green data for display data, black data for black insertion drive, blue data for display data, black data for black insertion drive The data is stored in the shift register 25.

  Then, when the liquid crystal display device 101 performs a display operation, the timing control unit 23 of the controller 4 sends a control signal to the gate driver 3 and the source driver 2 in accordance with a video signal input from the outside. As a result, the gate driver 3 applies a scanning signal voltage to each scanning line and sequentially turns on the switching elements of each pixel.

  During the display period, the source driver 2 applies a voltage corresponding to each color of the video signal to each signal line in accordance with the timing when the gate driver 3 applies the scanning signal voltage to each scanning line. When the gate driver 3 applies the scanning signal voltage to the scanning line, the switching elements of the pixels arranged in the scanning line are turned on, and the accumulation of the pixels arranged on the scanning line through the signal lines is performed. A voltage corresponding to the video signal is held in the capacitor, and a voltage corresponding to the video signal is written to the display element. Thereby, the liquid crystal molecules 62 of the liquid crystal display panel 10 are modulated, and the transmittance of light emitted from the backlight 111 changes. As a result, an image corresponding to the video signal is displayed on the liquid crystal display panel 10.

  In the black insertion period, the source driver 2 applies a voltage corresponding to black to each signal line in accordance with the timing at which the gate driver 3 applies the scanning signal voltage to each scanning line. When the gate driver 3 applies the scanning signal voltage to the scanning line, the switching elements of the pixels arranged in the scanning line are turned on, and the accumulation of the pixels arranged on the scanning line through the signal lines is performed. A voltage corresponding to black is held in the capacitor, and a voltage corresponding to black is written to the display element. Thereby, the liquid crystal molecules 62 of the liquid crystal display panel 10 are modulated, and the transmittance of light emitted from the backlight 111 changes. As a result, a black image is displayed on the liquid crystal display panel 10.

  Further, the timing control unit 23 supplies a backlight control signal, which is a signal for interlocking with the driving of the liquid crystal display panel 10 by the source driver 2 and the like, to the backlight control unit 119. As the backlight control signal, a control signal sent from the timing control unit 23 to the gate driver 3 or the source driver 2 can be used. Specifically, a clock signal, a horizontal synchronization signal, a vertical synchronization signal, or the like can be used as the backlight control signal.

  The backlight control unit 119 adjusts the backlight 111 so that the lighting ratios of the LEDs of the respective colors (R, G, B) determined by the dimming unit 118 according to the backlight control signal sent from the timing control unit 23. Each LED (R, G, B) is controlled to be turned on / off. The operation of the light control unit 118 will be described later.

  That is, the backlight control unit 119 starts writing the voltage corresponding to each color to the pixel on the scanning line that is scanned first on the display screen of the liquid crystal display panel 10, and at the same time, the LED of the backlight 111 corresponding to the color. Lights up. Then, the backlight control unit 119 turns on the LED corresponding to the color for a period corresponding to the lighting ratio of the color determined by the dimming unit 118, and then turns off the LED corresponding to the color.

  For example, the liquid crystal display device 101 displays each color of display data in the order of a red display period, a black insertion period, a green display period, a black insertion period, a blue display period, and a black insertion period in one frame period (or one field period). When performing black display for black insertion driving, the backlight control unit 119 controls lighting / extinguishing of the backlight 111 as follows.

  When one frame period (or one field period) starts, a red display period starts. Then, the backlight control unit 119 turns on the red LED that is the light source of the backlight 111 at the timing when the voltage corresponding to the red color of the display data is started to be written to the pixel on the scanning line that is scanned first. Then, after the red LED, which is the light source of the backlight 111, is turned on for a period corresponding to the red lighting ratio determined by the light control unit 118, the red LED is turned off. Here, for example, assuming that the dimming unit 118 determines that the lighting ratio of red is 30%, the backlight control unit 119 lights the backlight 111 for a period of 30% of the red display period, and thereafter The red LED is turned off.

  Next, the red display period elapses, the black insertion period subsequent to the red display period elapses, and the green display period starts. Then, the backlight control unit 119 turns on the green LED that is the light source of the backlight 111 at the timing when the voltage corresponding to the green color of the display data starts to be written to the pixel on the scanning line that is scanned first. Then, after the green LED, which is the light source of the backlight 111, is turned on for the period corresponding to the green lighting ratio determined by the light control unit 118, the green LED is turned off. For example, when the dimming unit 118 determines that the green lighting ratio is 35%, the green LED that is the light source of the backlight 111 is turned on only for the period of 35% of the green display period, and then the green LED is turned on. Turn off the LED.

  Next, the green display period elapses, the black insertion period next to the green display period elapses, and the blue display period starts. Then, the backlight control unit 119 turns on the blue LED that is the light source of the backlight 111 at the timing when the voltage corresponding to the blue color of the display data starts to be written to the pixel on the scanning line that is scanned first. Then, after turning on the blue LED, which is the light source of the backlight 111, for the period corresponding to the blue lighting ratio determined by the dimmer 118, the blue LED is turned off. For example, when the dimming unit 118 determines that the lighting ratio of blue is 40%, the blue LED that is the light source of the backlight 111 is turned on only for 40% of the blue display period, and then the blue LED is turned on. Turn off the LED.

  In this way, an image for one frame (or one field) is displayed on the liquid crystal display panel 10.

  By repeating the above operation, the video signal input to the frame memory 22 is continuously displayed on the liquid crystal display panel 10.

  The dimming unit 118 inputs the luminances of R, G, and B of the backlight 111 detected by the optical sensor unit 126, and / or the luminances of the LEDs of the respective colors provided in the input backlight 111. Dimming so that the chromaticity is the specified value or reference value. That is, dimming by the dimming unit 118 is performed by adjusting the lighting ratio of the LEDs of the respective colors of the backlight 111.

  By using such a conventional liquid crystal display device 101, it is possible to realize high contrast, high transmittance, high resolution, and low power consumption.

  The dimmer 118 corrects the luminance difference and chromaticity difference of the backlight 111 using the R, G, and B luminances of the backlight 111 detected by the optical sensor unit 126.

  As a result, an optimal white balance can be maintained, and variations in light sources such as LEDs and color shifts during temperature changes can be suppressed.

In addition, in a liquid crystal display device of a type in which a color filter is provided on the counter substrate instead of the field sequential method, the variation of the light source or the It is possible to suppress a luminance shift that occurs when the temperature changes.
JP 2003-280617 A JP 2003-233352 A

  However, in the conventional liquid crystal display device 101, when one frame period (or one field period) starts and the red display period starts, writing of the voltage corresponding to the red color of the display data to the pixels on the scanning line that is scanned first is started. At the same time, the red LED that is the light source of the backlight 111 is turned on.

  In the conventional liquid crystal display device 101, when the green display period is started, the voltage corresponding to the green color of the display data is started to be written to the pixels on the scanning line that is scanned first, and at the same time, the light source of the backlight 111 is used. A certain green LED lights up.

  Further, in the conventional liquid crystal display device 101, when the blue display period starts, the voltage corresponding to the blue color of the display data is started to be written to the pixels on the scanning line that is scanned first, and at the same time, the light source of the backlight 111 A certain blue LED lights up.

  Thus, the conventional liquid crystal display device 101 lights the backlight 111 simultaneously with the start of the display period of each color in the display period of each color. That is, the conventional liquid crystal display device 101 performs control to turn on the backlight 111 in the first half and turn off the backlight in the second half in the display period of each color.

  For this reason, the backlight 111 is turned on while the voltage corresponding to the display data is not yet sufficiently written to the display element of the pixel. In addition, when the voltage corresponding to the display data is written to the display element of the pixel, the backlight 111 may already be turned off. In addition, during the period when the voltage corresponding to the display data is written in the display element of the pixel, a situation may occur in which the backlight is not lighted. In addition, during the period in which the voltage corresponding to the display data is written in the display display element of the pixel, there may be a situation in which the time during which the backlight is lit varies depending on the location of the liquid crystal display panel 10.

  Therefore, there may occur a problem that the contrast of the display screen of the liquid crystal display panel 10 of the conventional liquid crystal display device 101 is lowered. Furthermore, even when the same color is displayed on the display screen of the liquid crystal display panel 10 of the conventional liquid crystal display device 101, there may be a problem that a luminance difference occurs depending on the location of the display screen. Furthermore, there may be a problem that high-luminance display corresponding to the backlight lighting period and luminance cannot be performed on the display screen of the liquid crystal display panel 10 of the conventional liquid crystal display device 101.

  These problems will be described in more detail with reference to FIG.

  FIG. 17 is a timing chart showing the voltage waveform written in the display element of a specific pixel of the conventional liquid crystal display device 101 and the on / off state of each color of the backlight 111.

  In FIG. 17, the time has passed from the left side to the right side as viewed in the drawing.

  In FIG. 17, reference numeral 75a denotes a voltage waveform written to the display element of any one pixel (hereinafter referred to as the first pixel) present on the scanning line that is scanned first in one frame (or one field) period. , 75c are voltage waveforms written in the display element of any one pixel (hereinafter referred to as the last pixel) existing on the scanning line scanned last in one frame (or one field) period, and 75b is A specific pixel (on a scanning line located in the middle of a scanning line that is scanned first in one frame (or one field) and a scanning line that is scanned last in one frame (or one field) ( This is a voltage waveform written in the display element (hereinafter referred to as the middle pixel).

  Note that FIG. 17 illustrates a case where voltages corresponding to the same color are written in the first pixel, the middle pixel, and the last pixel in order to facilitate understanding.

  Therefore, the voltage waveform 75b written to the display element of the middle pixel is a waveform obtained by simply shifting the voltage waveform 75a written to the display element of the first pixel to the right side. The voltage waveform 75c written to the display element of the last pixel is a waveform obtained by simply shifting the voltage waveform 75b written to the display element of the middle pixel to the right.

  In FIG. 17, reference numeral 74 denotes a black voltage for black insertion driving, 71 denotes a voltage corresponding to red of display data, 72 denotes a red writing voltage to be written to the pixel in the red display period, and 72 denotes , Indicates a voltage corresponding to the green color of the display data, indicates a green write voltage to be written to the pixel in the green display period, 73 indicates a voltage corresponding to the blue color of the display data, and blue write to be written to the pixel in the blue display period The voltage is shown.

  In FIG. 17, R_LED, G_LED, and B_LED indicate the ON / OFF state of the red LED, the green LED, and the blue LED, which are the light sources of the backlight 111, respectively, the HIGH state indicates ON, and the LOW state indicates Shows off.

  FIG. 17 shows a case where the light control unit 118 determines the lighting ratio of each color LED of the backlight 111 to be 70%. Therefore, the period during which R_LED is in the High state is 70% of the red writing (red display period). The period during which G_LED is in the high state is 70% of the green writing (green display period). Further, the period during which the B_LED is in the high state is 70% of blue (blue display period).

  As can be seen from the voltage waveform 75a of the display element of the first pixel in FIG. 17, simultaneously with the start of writing of the red write voltage 71 to the display element of the first pixel, the red LED is turned on, After the voltage written in the display element reaches the red writing voltage 71, the red LED is turned off after a while.

  Similarly, simultaneously with the start of writing of the green write voltage 72 to the display element of the first pixel, the green LED is lit and the voltage written to the display element of the first pixel reaches the green write voltage 72. Then, after a while, the green LED is turned off.

  Similarly, the blue LED is turned on simultaneously with the start of writing of the blue writing voltage 73 to the display element of the first pixel, and the voltage written to the display element of the first pixel reaches the blue writing voltage 73. Then, after a while, the blue LED is turned off.

  However, as can be seen from the voltage waveform 75b of the display element of the middle pixel, the red LED is already lit before the writing of the red write voltage 71 is started on the display element of the middle pixel. The red LED is already extinguished immediately before the voltage written in the display element of the middle pixel reaches the red writing voltage 71.

  Further, as can be seen from the voltage waveform 75c of the display element of the last pixel, the red LED is already lit before the writing of the red write voltage 71 is started on the display element of the last pixel. The red LED is already extinguished long before the voltage written in the display element of the last pixel reaches the red writing voltage 71.

  The same is true for green and blue LEDs.

  That is, for red display, the red LED is already lit before the display element of the first pixel, the display element of the middle pixel, and the display element of the last pixel reach the red writing voltage 71, respectively. As a result, the contrast decreases. For the green display and the blue display, the contrast decreases for the same reason as the red display.

  For red display, the display element of the first pixel has the longest time to reach the red writing voltage 71 during the period when the red LED is lit, and the display element of the middle pixel is red. The red LED is already extinguished immediately before reaching the write voltage 71. Further, in the display element of the last pixel, the red LED has already been turned off long before the red writing voltage 71 is reached. The same can be said for the green display and the blue display.

  Thus, even when the same color is displayed in the first pixel, the middle pixel, and the last pixel, a luminance difference is generated. Therefore, even when the same color is displayed on the display screen of the liquid crystal display panel 10 of the conventional liquid crystal display device 101, the pixel on the scanning line scanned first is directed to the pixel on the scanning line scanned last. As a result, the luminance gradually decreases.

  For red display, the period in which the red LED is lit is different from the period in which the first pixel, the middle pixel, and the last pixel reach the red writing voltage 71. Therefore, it is impossible to perform display with a high luminance corresponding to the lighting period and luminance of the red LED. Similarly to the red display, the green display can not be performed with a high luminance corresponding to the lighting period and luminance of the green LED. Similarly to the red display, the blue display can not be performed with a high luminance corresponding to the lighting period and luminance of the blue LED.

  Thus, in a conventional liquid crystal display device that performs dimming by changing the lighting ratio of the backlight light source, the backlight light source is turned on before the pixel display element reaches a voltage corresponding to the display data. Therefore, there is a problem that the contrast is lowered.

  Further, in a conventional liquid crystal display device that performs dimming by changing the lighting ratio of the light source of the backlight, even when displaying the same color, the pixel of each scanning line in the period during which the backlight is lit Since the voltage waveforms are different, there is a problem that a luminance difference is generated on the display screen of the display panel of the liquid crystal display device.

  In addition, in a conventional liquid crystal display device that performs dimming by changing the lighting ratio of the light source of the backlight, the period during which the backlight is lit differs from the period during which the writing voltage for each color is reached. However, there is a problem in that display with high luminance corresponding to the lighting period and luminance of the light source of the backlight cannot be performed.

  Further, in the conventional liquid crystal display device that performs dimming by changing the lighting ratio of the light source of the backlight, as described above, the voltage corresponding to the display data is written to the first pixel with the light source of the backlight of each color. Since it is turned on at the same time as the start, there is a problem that the contrast level of the display screen of the display panel, the magnitude of the brightness, and the degree of the brightness difference cannot be freely dimmed as designed.

  Such a problem appears remarkably in the above-described conventional liquid crystal display device 101, but the same problem occurs in a general conventional active matrix liquid crystal display device. For example, such a problem occurs not only in the field sequential method but also in a liquid crystal display device that performs black insertion driving of a type in which a color filter is provided on the counter substrate, and a field sequential method liquid crystal display that does not use the OCB mode. The same problem occurs in a field sequential type liquid crystal display device that does not perform black insertion driving. As described above, the above-described problems occur in various active matrix liquid crystal display devices.

  In view of the above problems, an object of the present invention is to provide a liquid crystal display device capable of displaying an image with a good contrast, a driving method of the liquid crystal display device, a program, and a recording medium.

  Another object of the present invention is to provide a liquid crystal display device, a driving method of the liquid crystal display device, a program, and a recording medium that can suppress the occurrence of a luminance difference depending on the location of the display screen in consideration of the above problems. It is what.

  The present invention also provides a liquid crystal display device capable of high-luminance display corresponding to the backlight lighting period and luminance in consideration of the above problems, a driving method of the liquid crystal display device, a program, and a recording medium It is intended to do.

  In addition, in consideration of the above-described problems, the present invention provides a liquid crystal display device and a liquid crystal display capable of freely dimming the degree of contrast of the display screen of the display panel, the magnitude of the luminance, and the degree of the luminance difference as designed. It is an object of the present invention to provide an apparatus driving method, a program, and a recording medium.

In order to solve the above-described problems, a first aspect of the present invention provides a liquid crystal having signal lines and scanning lines formed in a matrix and a liquid crystal display element formed corresponding to the intersection of the signal lines and scanning lines. A display panel;
A source driver that applies an applied voltage corresponding to display data to a signal line of the liquid crystal display panel;
Intermittent lighting that is intermittently lit is possible, a backlight that illuminates the liquid crystal display panel,
Based on the voltage in which the applied voltage is written to the liquid crystal display element via the signal line, the lighting disclosure timing, the lighting end timing, and the middle of the predetermined lighting period for the predetermined lighting period of the backlight The liquid crystal display device includes a backlight control unit that determines at least one of the timings.

Further, according to a second aspect of the present invention, the liquid crystal display panel has a storage capacitor for each liquid crystal display element,
The voltage in which the applied voltage is written to the liquid crystal display element via the signal line is a voltage in which the applied voltage held in the storage capacitor via the signal line is written to the liquid crystal display element. The liquid crystal display device of the first aspect of the present invention.

  According to a third aspect of the present invention, when the voltage written in the liquid crystal display element reaches the applied voltage, the backlight control unit determines that the middle period of the predetermined lighting period is (1) 1 The time when the voltage written in the liquid crystal display element existing on the scanning line scanned last in the frame period or one field period reaches the applied voltage, and (2) the first scanning is performed in one frame period or one field period. Determining the lighting start time and the lighting end time so that the voltage written on the liquid crystal display element existing on the scanning line coincides with the middle time of the time when the voltage leaves the applied voltage. It is a liquid crystal display device of the present invention.

  According to a fourth aspect of the present invention, when the voltage written in the liquid crystal display element does not reach the applied voltage, the backlight control unit is configured so that the middle period of the predetermined lighting period is on the middle scanning line. A liquid crystal display device according to a second aspect of the present invention, wherein the lighting start time and the lighting end time are determined so that the voltage written to the liquid crystal display element existing in the first and second voltages coincides with a time when the voltage approaches the applied voltage. .

  According to a fifth aspect of the present invention, the backlight control unit includes the lighting start time according to a ratio between the magnitude of the rising slope of the voltage written to the liquid crystal display element and the magnitude of the falling slope. It is a liquid crystal display device according to a fourth aspect of the present invention that corrects the lighting end time.

  Further, in the sixth aspect of the present invention, the backlight control unit is configured such that the area obtained by integrating the voltage written in the liquid crystal display element from the lighting start time to the lighting end time takes an extreme value. In the liquid crystal display device according to the second aspect of the present invention, the lighting start time and the lighting end time are determined.

  The seventh aspect of the present invention is the liquid crystal display device according to the second aspect of the present invention, wherein the predetermined lighting period can be varied.

In the eighth aspect of the present invention, OCB mode liquid crystal is used for the liquid crystal display panel.
The liquid crystal display panel performs color display with temporal additive color mixing,
The source driver applies the applied voltage corresponding to the color of display data to the signal line during a display period for each color provided within a period of one frame or one field, and after the display period of each color A black applied voltage corresponding to black is applied to the signal line during each black insertion period provided,
During the display period for each color, the backlight is turned on for a predetermined lighting period based on the degree of voltage at which the applied voltage held in the storage capacitor is written to the liquid crystal display element via the signal line. In the liquid crystal display device according to the second aspect of the present invention, at least one of a disclosure time, a lighting end time, and a middle time of the predetermined period is determined.

  In the ninth aspect of the present invention, the display period for each color is a red display period for displaying red, a green display period for displaying green, and a blue display period for displaying blue. Liquid crystal display device.

In the tenth aspect of the present invention, the backlight is divided into a plurality of backlight blocks in parallel to the scanning lines.
The source driver applies an applied voltage corresponding to display data to the signal line during a display period provided within a period of one frame or one field, and turns black during a black insertion period provided after the display period. A corresponding black applied voltage is applied to the signal line,
The backlight control unit, when the portion of the display area of the liquid crystal display panel facing each divided backlight block is the black insertion period, removes the backlight block from the predetermined lighting period. The liquid crystal display device of the second aspect of the present invention is turned off.

  Further, according to an eleventh aspect of the present invention, when the voltage written in the liquid crystal display element reaches the applied voltage, the backlight control unit is set to the middle of the predetermined lighting period for each backlight block. (1) The time when the voltage written in the liquid crystal display element existing on the scanning line scanned last for the backlight block in one frame period or one field period reaches the applied voltage (2) ) The voltage written in the liquid crystal display element existing on the scanning line first scanned for the backlight block in one frame period or one field period coincides with the middle time of the time when the voltage leaves the applied voltage. The tenth aspect of the present invention determines the lighting start time and the lighting end time for the backlight block. It is a liquid crystal display device.

  In addition, the twelfth aspect of the present invention is directed to the backlight control unit, wherein when the voltage written in the liquid crystal display element does not reach the applied voltage, the predetermined value of the backlight block is set for each backlight block. The backlight block is lit so that the middle time of the lighting period coincides with the time when the voltage written in the liquid crystal display element existing on the scanning line in the middle of the backlight block is closest to the applied voltage. The liquid crystal display device according to a tenth aspect of the present invention, wherein a start time and a lighting end time are determined.

A thirteenth aspect of the present invention is a liquid crystal display panel having signal lines and scanning lines formed in a matrix, and liquid crystal display elements formed corresponding to the intersections of the signal lines and the scanning lines,
A source driver that applies an applied voltage corresponding to display data to a signal line of the liquid crystal display panel;
A method of driving a liquid crystal display device that can be intermittently lit intermittently and drives a liquid crystal display device including a backlight that illuminates the liquid crystal display panel,
Based on the degree of voltage at which the applied voltage is written to the liquid crystal display element via the signal line, the lighting disclosure timing, the lighting end timing, and the predetermined lighting period of the predetermined lighting period of the backlight. A method for driving a liquid crystal display device, comprising a backlight control step for determining at least one of the middle periods.

  Further, the fourteenth aspect of the present invention provides the predetermined backlight of the liquid crystal display device according to the first aspect of the present invention, based on the degree of voltage at which the applied voltage is written to the liquid crystal display element via the signal line. This is a program for causing a computer to function as a backlight control unit that determines at least one of the lighting disclosure timing, the lighting end timing, and the middle timing of the predetermined lighting period.

  The fifteenth aspect of the present invention is a recording medium that records the program of the fourteenth aspect of the present invention, and is a recording medium that can be processed by a computer.

  The present invention can provide a liquid crystal display device capable of displaying an image with good contrast, a driving method of the liquid crystal display device, a program, and a recording medium.

  The present invention can provide a liquid crystal display device, a driving method of the liquid crystal display device, a program, and a recording medium that can suppress the occurrence of a luminance difference depending on the location of the display screen.

  The present invention can provide a liquid crystal display device, a liquid crystal display device driving method, a program, and a recording medium that can display with high luminance corresponding to the lighting period and luminance of the backlight.

  The present invention relates to a liquid crystal display device capable of freely dimming the degree of contrast of the display screen of the display panel, the magnitude of the luminance, and the luminance difference according to the design value, a driving method of the liquid crystal display device, a program, and A recording medium can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
In the first embodiment, a liquid crystal display device which is an embodiment of the liquid crystal display device of the present invention will be described, and an embodiment of a driving method of the liquid crystal display device of the present invention will also be described.

  FIG. 1 shows a block diagram of a liquid crystal display device 1 according to the first embodiment.

  A liquid crystal display device 1 according to the first embodiment shown in FIG. 1 is a field sequential type liquid crystal display device, like the conventional liquid crystal display device 101, which performs black insertion driving. The same parts as those of the conventional liquid crystal display device 101 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The difference between the liquid crystal display device 1 of the first embodiment and the conventional liquid crystal display device 101 is that the conventional liquid crystal display device 101 includes a backlight 111, a backlight control unit 119, a light control unit 118, and an optical sensor unit. In contrast, the liquid crystal display device according to the first embodiment includes the backlight 11, the backlight control unit 19, the light control unit 18, and the optical sensor unit 26.

  The backlight 11 is disposed on the back side of the active matrix liquid crystal display panel 10 and is divided into a plurality of backlight blocks. Each backlight block has a red LED, a green LED, A blue LED and a light guide plate are provided.

  An outline of the backlight 11 is shown in FIGS. FIG. 2A is a plan view of the backlight 11 viewed from a direction orthogonal to the display surface of the liquid crystal display panel 10, and FIG. 2B is a side view of the backlight 11.

  As shown in FIGS. 2A and 2B, the backlight 11 is divided into a plurality of backlight blocks 15a to 15e. In each of the plurality of backlight blocks 15a to 15e, LEDs 13a to 13e and LEDs 14a to 14e, which are light sources, are respectively arranged. Here, LED13a-13e and LED14a-14e are respectively comprised from red LED, green LED, and blue LED.

  Further, light guide plates 12a to 12e are respectively arranged in the plurality of backlight blocks 15a to 15e. Each of the backlight blocks 15a to 15e mainly illuminates the portion of the display area of the liquid crystal display panel 10 that the backlight block faces.

  Each of the backlight blocks 15a to 15e is provided with optical sensor units 16a to 16e (corresponding to the optical sensor unit 26 in FIGS. 1 and 3).

  4A and 4B show an example of the optical sensor units 15a to 15e. 4A is a plan view of any one of the optical sensor units 15a to 15e, and FIG. 4B is a side view of any one of the optical sensor units 15a to 15e. FIG. As shown in FIGS. 4A and 4B, each of the photosensor portions 15a to 15e has three photodetecting elements 36a, 36b, and 36c formed on a substrate 37, and the photodetecting element 36a. , 36b, 36c, color filters 35a, 35b, 35c are formed. The color filters 35a, 35b, and 35c are color filters that transmit red, green, and blue light, which are the three primary colors, respectively. The light detection elements 36a, 36b, 36c and the color filters 35a, 35b, 35c are covered with a transparent cover 38 such as glass.

  The backlight control unit 19 transmits a backlight control signal (clock signal, horizontal synchronization signal) sent from the timing control unit 23 so that the lighting ratio of each color (R, G, B) determined by the dimming unit 18 is obtained. , Vertical synchronization signals, etc.) are used to determine the lighting start timing and lighting end timing of the LEDs 13a to 13e and LED 14a to LED 14e, and the respective LEDs 13a to 13e and LEDs 14a to 14e are turned on at the determined lighting start timing. The LEDs 13a to 13e and LEDs 14a to 14e are turned off at the determined lighting end time.

  That is, the backlight control unit 19 controls turning on / off of the LEDs 13a to 13e and 14a to 14e of the plurality of backlight blocks 15a to 15e in conjunction with the driving timing of the liquid crystal display panel 10 by the source driver 2 or the like. Is.

  Based on the luminance of each color (R, G, B) of each of the backlight blocks 15a to 15e detected by the light sensor unit 26, the light control unit 18 uses each color (R, G, and R) of each backlight block 15a to 15e. For the LEDs 13a to 13e and 14a to 14e of B), the luminance and / or chromaticity of the backlight is dimmed by adjusting the ratio of the lighting period of the LED of that color to the display period of each color.

  As in the description of the background art, the ratio of the lighting periods of the LEDs 13a to 13e and 14a to 14e for each color with respect to the display period of each color is referred to as the lighting ratio of that color.

  FIG. 3 is a diagram showing details of an illumination system such as the light control unit 18, the backlight control unit 19, and the backlight 11 in the liquid crystal display device 1 of FIG. 1.

  The dimming unit 18 includes a dimming control unit 33, a reference value storage unit 40, and a lighting ratio storage unit 44.

  The reference value storage unit 40 is a semiconductor memory in which a reference luminance and / or chromaticity is recorded in advance.

  The dimming control unit 33 determines that each of the backlight blocks 15a to 15e has a reference value storage unit 40 based on the detection result of the luminance of each of the backlight blocks 15a to 15e sent from each of the light sensor units 16a to 16e. The lighting ratios of the respective colors of the LEDs 13a to 13e and 14a to 14e of the backlight blocks 15a to 15e are determined so as to match the reference luminance and / or chromaticity stored in Is a circuit to be stored.

  The lighting ratio storage unit 44 is a semiconductor memory that stores the lighting ratio of each color of the LEDs 13a to 13e and 14a to 14e for each of the backlight blocks 15a to 15e.

  In addition, the backlight control unit 19 includes an analysis result storage unit 45, a calculation unit 46, and a time storage unit 47.

  The analysis result storage unit 45 is a semiconductor memory that stores various times obtained by analyzing a voltage waveform written to a display element of a pixel.

  The calculation unit 46 determines the lighting start timing and lighting end timing of each of the backlight blocks 15a to 15e based on information on various times stored in the analysis result storage unit 45, and the determined lighting start timing and lighting determined. The end time is stored in the time storage unit 47.

  The time storage unit 47 is a semiconductor memory that stores the lighting start timing and lighting end timing of each of the backlight blocks 15a to 15e.

  1 and 3 are the same as those described in the background art except for the above.

  Next, the operation of the liquid crystal display device 1 according to the first embodiment will be described, and an embodiment of the liquid crystal display device driving method of the present invention will also be described.

  When the power source of the liquid crystal display device 1 is turned on, the liquid crystal display device 1 performs transfer driving in the same manner as the conventional liquid crystal display device 101 described in the background art.

  When the transfer driving is completed and the liquid crystal display device 1 can perform the display operation, the liquid crystal display device 1 starts the display operation.

  The operation of the liquid crystal display device 1 to write the video display signal to the pixel is the same as the operation of the conventional liquid crystal display device 101 described in the background art. That is, in one frame period (or one field period), a red display period, a black insertion period, a green display period, a black insertion period, a blue display period, and a black insertion period are provided in this order.

  FIG. 5 shows an equivalent circuit of a pixel to which a video signal is written as a pixel 82. In FIG. 5, the pixel 82 includes a TFT 83 that is a switching element, a storage capacitor 84, and a display element 85. The display element 85 includes a pixel electrode, a portion of a counter electrode facing the pixel electrode, and a liquid crystal layer sandwiched between the pixel electrode and the counter electrode.

  The gate driver 3 sequentially applies a scanning voltage to each scanning line, and the switching element (TFT) 83 of each pixel 82 arranged in the scanning line is turned on. In accordance with the timing, the source driver 2 writes a voltage corresponding to each color of display data or a voltage corresponding to black to each pixel 82 arranged on the scanning line through each signal line.

  Thereby, the voltage corresponding to each color of the display data or the voltage corresponding to black is written and held in the storage capacitor 84 of each pixel, and the voltage corresponding to each color of the display data is stored in the liquid crystal display element 85. A voltage corresponding to black is written.

  Even after the switching element (TFT) 83 changes from the on state to the off state, a voltage corresponding to the video signal held in the storage capacitor 84 is written to the display element 85. The voltage written to the display element 86 changes relatively slowly and reaches a voltage corresponding to the video signal held in the storage capacitor 84.

Thereby, the liquid crystal molecules 62 (FIGS. 15A and 15B) of the liquid crystal display panel 10 are modulated, and the transmittance of light emitted from the backlight 11 changes. As a result, an image corresponding to the video signal is displayed on the liquid crystal display panel 10. The details of the waveform of the voltage written in the display element 86 will be described later. Next, the operation of the illumination system such as the backlight 11 will be described.

  The operation of the illumination system such as the backlight 11 will be described by focusing on the backlight block 15a constituting the backlight 11. However, the backlight blocks 15b to 15e have the same operation as the backlight block 15a. Therefore, the description of the operation of the backlight blocks 15b to 15e is omitted.

  FIG. 6 shows the relationship between the backlight block 15a and the display area portion of the liquid crystal display panel 10 facing the backlight block 15a. In FIG. 6, as indicated by arrows (scanning direction), scanning voltages are sequentially applied to the scanning lines 76 from the top to the bottom of the sheet.

  Therefore, the scanning line shown as the first scanning line 77a is first scanned in the portion of the display area of the liquid crystal display panel 10 facing the backlight block 15a. In addition, the scanning line shown as the last scanning line 77c is finally scanned in the display area portion of the liquid crystal display panel 10 facing the backlight block 15a. The scanning line shown as the middle scanning line 77b is located between the first scanning line 77a and the last scanning line 77c, and the timing when the first scanning line 77a is scanned and the last scanning line 77c are Scanning is performed at a time intermediate to the scanning time.

  In FIG. 6, the first pixel 78a is an arbitrary specific pixel existing on the first scanning line 77a, and the middle pixel 78b is an arbitrary specific pixel existing on the central scanning line 77b. The last pixel 78c is an arbitrary specific pixel existing on the last scanning line 77c. The first pixel 78a, the middle pixel 78b, and the last pixel 78c have the same configuration as the pixel 82 described in FIG.

  FIG. 7 shows voltage waveforms written in the display elements of the first pixel 78a, the middle pixel 78b, and the last pixel 78c shown in FIG. 6, and the ON / OFF states of the LEDs of the respective colors in the backlight block 15a. It is a timing chart figure. In FIG. 7, time elapses from the left side toward the right side as viewed on the paper.

  Reference numeral 75a denotes a voltage waveform written to the display element of the first pixel 78a.

  Reference numeral 75b denotes a voltage waveform written to the display element of the middle pixel 78b.

  75c is a voltage waveform written in the display element of the last pixel 78c.

  In FIG. 7, R_LED, G_LED, and B_LED indicate the ON / OFF state of the red LED, the green LED, and the blue LED among the LEDs 13a and 14a that are the light sources of the backlight block 15a, respectively, and are in a high state. Indicates lighting, and the Low state indicates light extinction.

  In FIG. 7, reference numeral 74 denotes a black voltage for black insertion driving, 71 denotes a voltage corresponding to red of display data, 72 denotes a red writing voltage to be written to the pixel in the red display period, and 72 denotes , A voltage corresponding to the green color of the display data, a green write voltage to be written to the display element of the pixel 78 during the green display period, and a voltage 74 corresponding to the blue color of the display data, and the pixel 78 during the blue display period. The blue write voltage to be written to the display element is shown.

  For ease of understanding, FIG. 7 illustrates a case where the first pixel 78a, the middle pixel 78b, and the last pixel 78c all display the same color.

  FIG. 7 shows a case where the light control unit 18 determines that the lighting ratios of the LEDs of the respective colors of the backlight block 15a are all 70%. That is, information that the lighting ratio of the LEDs of the LEDs 13a and 14a of the backlight 15a is 70% is stored in the lighting ratio storage unit 44 of the light control unit 18.

  The backlight control unit 19 reads this information from the lighting ratio storage unit 44 of the dimming unit 18, and further reads information stored in the analysis result storage unit 45.

  FIG. 8A shows information stored in the analysis result storage unit 45.

  The last pixel write voltage arrival time 45a indicates the time from when the display period of each color starts until the voltage written to the display element of the last pixel 78c reaches the voltage corresponding to each color of the display data. ing.

  The first pixel writing voltage leaving time 45b indicates the time from when the display period of each color starts until the voltage written to the display element of the first pixel 78a leaves from the voltage corresponding to each color of the display data. ing.

  The last pixel black insertion voltage arrival time 45c is from when the display period of each color starts until the voltage written in the display element of the last pixel 78c reaches a voltage corresponding to black for black insertion. Shows time.

  In the first embodiment, the voltage waveforms 75a, 75b, and 75c written to the display element of the first pixel 78a, the display element of the middle pixel 78b, and the display element of the last pixel 78c are actually used as testers. By analyzing the measured voltage waveforms 75a and 75c, the last pixel write voltage arrival time 45a, the first pixel write voltage departure time 45b, and the last pixel black insertion voltage arrival time shown in FIG. 45c was determined. Then, the obtained last pixel writing voltage arrival time 45a, first pixel writing voltage leaving time 45b, and last pixel black insertion voltage reaching time 45c are stored in advance in the analysis result storage unit 45 as shown in FIG. I remembered it.

  Then, the calculation unit 46 uses the backlight control signal (clock signal, horizontal synchronization signal, vertical synchronization signal, etc.) sent from the controller 4 to obtain the last pixel write voltage arrival time 45a, the first pixel write voltage. The lighting start time and lighting end of each of the red LED, green LED, and blue LED of the LEDs 13a and 14a of the backlight block 15a are calculated by using the leaving time 45b and the last pixel black insertion voltage arrival time 45c. The time is determined and stored in the time storage unit 47. Note that how to calculate the lighting start time and the lighting end time by the calculation unit 46 will be described later.

  FIG. 8B shows the lighting start timing and lighting end timing of each of the red LED, the green LED, and the blue LED among the LEDs 13 a and 14 a of the backlight block 15 a stored in the timing storage unit 47.

  In FIG. 8B, red LED lighting start timing 47a and red LED lighting end timing 47b indicate the lighting start timing and lighting end timing of the red LED of the LEDs 13a and 14a of the backlight block 15a, respectively. . In FIG. 8B, the green LED lighting start timing 47c and the green LED lighting end timing 47d are the green LED lighting start timing and lighting end timing of the LEDs 13a and 14a of the backlight block 15a, respectively. Show. In FIG. 8B, a blue LED lighting start timing 47e and a blue LED lighting end timing 47f indicate the lighting start timing and lighting end timing of the blue LED of the LEDs 13a and 14a of the backlight block 15a, respectively. ing.

  The backlight control unit 19 turns on the red LED of the LEDs 13a and 14a of the backlight block 15a at the timing when the red LED lighting start time 47a stored in the time storage unit 47 is reached. Then, the red LED of the LEDs 13a and 14a of the backlight block 15a is turned off at the timing when the red LED lighting end time 47b stored in the time storage unit 47 is reached. The backlight control unit 19 performs the same control for the green LED and the blue LED among the LEDs 13a and 14a of the backlight block 15a.

  When the backlight control unit 19 performs such control, in FIG. 7, among the LEDs 13a and 14a that are the light sources of the backlight block 15a, the red LED, the green LED, and the blue LED are turned on / off. , R_LED, G_LED, B_LED.

  Now, as described above, how to calculate the lighting start time and the lighting end time by the calculation unit 46 will be described with reference to FIG.

  The calculation unit 46 reads from the lighting ratio storage unit 44 information that the lighting ratio of the LEDs 13a and 14a of the backlight block 15a is 70%. Next, the calculating part 46 calculates | requires the lighting period of red LED of LED13a of the backlight block 15a, 14a by multiplying the lighting ratio read from the lighting ratio memory | storage part 44 with respect to a red display period. The calculation unit 46 performs the same processing for green and blue, thereby obtaining the lighting period of the green LED and the lighting period of the blue LED of the LEDs 13a and 14a of the backlight block 15a.

  In addition, the lighting period of the red LED of this embodiment is an example of the predetermined lighting period of the present invention, and the lighting period of the green LED of this embodiment is an example of the predetermined lighting period of the present invention. The lighting period of the blue LED in this embodiment is an example of the predetermined lighting period of the present invention.

  Next, using the backlight control signal, the calculation unit 46 actually starts writing a voltage corresponding to the red color of the display data to the display element of the first pixel 78 shown in FIG. 7), and the final pixel write voltage arrival time 45a stored in the analysis result storage unit 45 is added at the determined time T0. In this way, the time T1 when the voltage written in the display element of the last pixel 78 reaches the red writing voltage 71 is obtained (see FIG. 7).

  Furthermore, the calculation unit 46 stores the analysis result storage unit 45 in the analysis result storage unit 45 at a time T0 (see FIG. 7) at which writing of the voltage corresponding to the red color of the display data is actually started on the display element of the first pixel 78a shown in FIG. The stored first pixel write voltage leaving time 45b is added. In this way, the time T2 (see FIG. 7) at which the voltage written to the display element of the first pixel 78a departs from the red writing voltage 71 is obtained.

  The calculation unit 46 uses the LEDs 13a and 14a that are the light sources of the backlight block 15a so that the time between the time T1 and the time T2, that is, the time (T1 + T2) / 2 coincides with the middle of the lighting period of the red LED. Among them, the lighting start timing and lighting end timing of the red LED are obtained and stored in the timing storage unit 47 as the red LED lighting start timing 47a and the red LED lighting end timing 47b, respectively.

  The calculation unit 46 performs the same processing on the green LED and the blue LED among the LEDs 13a and 14a that are the light sources of the backlight block 15a, thereby causing the timing storage unit 47 to store the green LED lighting start timing 47c, green The LED lighting end timing 47d, the blue LED lighting start timing 47e, and the blue LED lighting end timing 47f are stored in the timing storage unit 47.

  FIG. 9 shows the first pixel 78a and the middle pixel 78b when the lighting periods of the red LED, green LED, and blue LED are the longest among the LEDs 13a and 14a that are the light sources of the backlight block 15a. FIG. 6 is a timing chart showing voltage waveforms written in the display elements of the last pixel 76c and lighting / extinguishing states of LEDs of respective colors in the backlight block 15a. The reference numerals and the like are the same as those in FIG.

  In FIG. 9, among the LEDs 13a and 14a that are the light sources of the backlight block 15a, the red LED is lit from the time T0 to the time T3, and the green LED is lit from the time T4 to the time T7. The blue LED is lit from time T8 to T11.

  The red display will be described. At time T3, the last pixel shown in FIG. 8A is displayed at time T0 when the writing of the voltage corresponding to the red color of the display data is actually started on the display element of the first pixel 78. This is the time when the black insertion voltage arrival time 45c is added. That is, time T3 is a time when the voltage written in the display element of the last pixel 78c reaches a voltage corresponding to black for black insertion. Therefore, after time T3, until writing of a voltage corresponding to green is started on the display element of the first pixel 78a, all pixels in the portion of the liquid crystal display panel 10 facing the backlight block 15a correspond to black. Voltage is written. When the red LED is lit when the voltage corresponding to black is written in all the pixels of the portion of the liquid crystal display panel 10 facing the backlight block 15a, the power consumption of the red LED is only increased. It doesn't help at all. Furthermore, when the voltage corresponding to black is written in the pixel, if the transmittance of the display element of the pixel is not completely zero, it may cause a decrease in contrast.

  For the same reason, when the red LED is turned on in the past from the time T0, the power consumption of the red LED is increased and the contrast is also lowered.

  Therefore, as the upper limit when the dimming control unit 33 increases the lighting ratio of the red LED, it does not protrude from the range of the lighting period of the red LED in FIG. 9 (period from time T0 to time T3). did.

  Such an operation can be realized as follows.

  That is, when the calculation unit 46 determines the red LED lighting start timing 47a by the above-described operation, if the red LED lighting start timing 47a is a time earlier than the timing T0, the red LED lighting is turned on. The start time 47a is made to coincide with the time T0. In addition, when the calculation unit 46 determines the red LED lighting end timing 47b by the operation described above, when the red LED lighting end timing 47b is a time later than the timing T3, the red LED lighting end timing 47b is determined. The lighting end time 47b is made to coincide with the time T3.

  For the green display, by performing the same process as the red display, the green LED lighting period protrudes from the range of the green LED lighting period (range from time T4 to time T7) in FIG. You can avoid it. For the blue display, by performing the same process as the red display, the blue LED lighting period is changed from the range of the blue LED lighting period (range from time T8 to time T11) in FIG. It can be prevented from protruding.

  FIG. 10 shows the first pixel 78a and the middle pixel when the lighting periods of the red LED, the green LED, and the blue LED among the LEDs 13a and 14a that are the light sources of the backlight block 15a are the shortest. FIG. 78 is a timing chart showing voltage waveforms written in the display elements of 78b and the last pixel 78c, and lighting / extinguishing states of LEDs of respective colors of the backlight block 15a. The reference numerals and the like are the same as those in FIG.

  In FIG. 10, among the LEDs 13a and 14a that are the light sources of the backlight block 15a, the red LED is lit from time T1 to time T2, and the green LED is lit from time T5 to time T7. The blue LED is lit from time T9 to T10. By setting the lighting ratio of each color, it is possible to realize the on / off state of each color LED in FIG. FIG. 10 shows an example in which the decrease in luminance is suppressed as much as possible by making the lighting period of the LEDs of the respective colors the longest within a range where no luminance difference occurs. In the first embodiment, the lighting ratio of each color is set so as not to be shorter than the lighting period of the LED of each color in FIG.

  Needless to say, the lighting ratio may be made smaller than the lighting ratio that is the lighting period of the LED of each color in FIG. 10 in order to improve the moving image visibility close to the impulse display such as CRT.

  Heretofore, how to calculate the lighting start time and the lighting end time by the calculation unit 46 has been described.

  The light control unit 18 stores a reference value for the backlight block 15a using the red luminance, the green luminance, and the blue luminance detected by the optical sensor unit 16a (see FIG. 2) constituting the optical sensor unit 26. The lighting ratio is determined so that the LEDs of the respective colors of the backlight block 15a match the reference luminance and / or chromaticity stored in the unit 40, and stored in the lighting ratio storage unit 44.

  By using the lighting ratio determined by dimming by the dimming unit 18 as described above, the calculation unit 46 described above determines the lighting start timing and lighting end timing of the LEDs of each color, so that the backlight block 15a is used as a reference. Dimming can be performed so as to match the reference luminance and / or chromaticity stored in the value storage unit 40.

  Further, by performing the same processing as described above for the backlight blocks 15b to 15e, it is possible to correct the luminance difference and chromaticity difference between the backlight blocks 15a to 15e. As a result, an optimal white balance can be maintained, and variations in light sources such as LEDs and color shifts during temperature changes can be suppressed.

  Further, in FIG. 7, the lighting ratio stored in the lighting ratio storage unit 44 increases by increasing the luminance stored in the reference value storage unit 40. In this way, when the lighting ratio stored in the lighting ratio storage unit 44 is increased to approach the lighting period of each LED shown in FIG. 9, the contrast decreases and the lighting period of each color LED becomes longer. Since the luminance increases, the luminance increases, and the luminance difference in the place increases. Therefore, when the liquid crystal display device 1 of the first embodiment increases the lighting ratio of the LEDs of the respective colors by increasing the lighting ratio and approaches the lighting period of each LED shown in FIG. Display with high brightness corresponding to the lighting period and brightness of the.

  In FIG. 7, the lighting ratio stored in the lighting ratio storage unit 44 decreases by decreasing the luminance stored in the reference value storage unit 40. In this way, when the lighting ratio stored in the lighting ratio storage unit 44 is decreased to approach the lighting period of each LED shown in FIG. 10, the contrast increases and the lighting period of each color LED decreases. Therefore, the luminance decreases, and the luminance difference at the place decreases. Therefore, in the liquid crystal display device 1 of the first embodiment, a luminance difference is generated depending on the location of the display screen by reducing the lighting ratio and shortening the lighting period to approach the lighting period of each LED shown in FIG. This can be suppressed and display with high contrast is possible.

  As described above, by changing the setting of the reference luminance and / or chromaticity stored in the reference value storage unit 40 and increasing / decreasing the lighting ratio of each color LED, the liquid crystal according to the first embodiment is used. The display device 1 can freely dimm the degree of contrast of the display screen of the liquid crystal display panel 10, the magnitude of the luminance, and the degree of luminance difference as designed values.

  Further, as shown in FIG. 10, the liquid crystal display device 1 according to the first embodiment can reduce the lighting time of the LEDs 13a and 14a of the backlight block 15a, for example, when the lighting ratio is decreased. High contrast display can be performed. By utilizing this, the liquid crystal display device 1 of the first embodiment can be used for the purpose of efficiently lighting the LEDs 13a and 14a of the backlight block 15a.

  That is, by shortening the lighting time of the LEDs 13a and 14a of the backlight block 15a as much as possible and increasing the voltage supplied to the LEDs 13a and 14a of the backlight block 15a, the LEDs 13a and 14a and the like emit light with high brightness. Let In this way, the liquid crystal display device 1 can perform display with high contrast, and can further reduce power consumption.

  In the first embodiment, as shown in FIG. 2, the backlight 11 is divided into a plurality of backlight blocks 15 a to 15 e, so that the display screen can be displayed more than when the backlight 11 is not divided. The difference in brightness depending on the location is small, and high-contrast display is possible.

  In the first embodiment, the voltage waveforms 75a, 75b, and 75c of the display elements of the first pixel 78a, the middle pixel 78b, and the last pixel 78c are actually measured, and the measured voltage waveforms 75a and 75c are measured. Although it has been described that the last pixel write voltage arrival time 45a, the first pixel write voltage departure time 45b, and the last pixel black insertion voltage arrival time 45c shown in FIG. 8A are obtained by analysis, the present invention is not limited thereto. Absent.

  The last pixel writing voltage arrival time 45a, the first pixel writing voltage leaving time 45b, and the last pixel black insertion voltage reaching time 45c shown in FIG. 8A are the liquid crystal material used for the liquid crystal display panel 10 and the black insertion driving time. Therefore, the voltage corresponding to black is determined according to the timing of writing the voltage to the first pixel 78a, the last pixel 78c, and the like. Accordingly, the voltage waveform 75a of the display element of the first pixel 78a, based on the liquid crystal material to be used and the timing of writing the voltage corresponding to black for black insertion driving to the first pixel 78a, the last pixel 78c, etc. A voltage waveform 75c of the last pixel 78c is predicted, and from the predicted voltage waveforms 75a and 78c, the last pixel write voltage arrival time 45a, the first pixel write voltage leave time 45b, and the last shown in FIG. The pixel black insertion voltage arrival time 45c may be obtained.

  In the first embodiment, a method for determining the red LED lighting start time 47a, the red LED lighting end time 47b, etc. for the lighting period according to the lighting ratio determined by the dimming control unit 33, As an upper limit when the LED lighting ratio is increased, the method of preventing the red LED lighting period range (period from time T0 to time T3) in FIG. 9 from protruding has been described. Absent. The following first method and second method can also be used.

  First, the first method will be described. After the calculation unit 46 calculates the middle time between the time T1 and the time T2, that is, the time (T1 + T2) / 2, the time length from the time (T1 + T2) / 2 to the time T0 and the time (T1 + T2) / The ratio of the time length from 2 to the time T3 is the time length from the time (T1 + T2) / 2 to the red LED lighting start time 47a and the time from the time (T1 + T2) / 2 to the red LED lighting end time. The red LED lighting start timing 47a and the red LED lighting end timing 47b are determined so as to match the ratio with the time length up to 47b.

  Then, when the determined red LED lighting start timing 47a and red LED lighting end timing 47b are the past time from the time T0 and the future time from the time T3, respectively, the red LED lighting start timing 47a and The red LED lighting end time 47b is made to coincide with the time T0 and the time T3. By similarly processing the green LED and the blue LED, the lighting start timing and lighting end timing can be determined.

  The second method is to determine the red LED lighting start timing 47a, the red LED lighting end timing 47b, etc., either the method described in the first embodiment or the first method. To decide. Then, an upper limit of the lighting ratio is calculated in advance so that either the red LED lighting start timing 47a or the red LED lighting end timing 47b coincides with the timing T0 or the timing T3, and the dimming control unit 33 adjusts the lighting ratio. What is necessary is just to make it a lighting ratio not exceed the upper limit of the lighting ratio calculated | required previously, when lighting.

(Second Embodiment)
Next, a second embodiment will be described.

  In the first embodiment, the liquid crystal display device of the field sequential type, which performs black insertion driving, and the driving method of the liquid crystal display device have been described. Also in the second embodiment, as in the first embodiment, a field sequential type liquid crystal display device that performs black insertion driving and a driving method of the liquid crystal display device will be described.

  In the liquid crystal display device according to the first embodiment, as described in the timing charts of FIGS. 7, 9, and 10, for example, the case where the voltage written to the display element of the pixel 78 reaches the red write voltage 71 will be described. did. That is, the case where the voltages written to the display elements of the first pixel 78a, the middle pixel 78b, and the last pixel 78c reach the writing voltage and black writing voltage of each color and take a substantially constant value for a predetermined time. did.

  On the other hand, the voltage written to the display element of the pixel may not completely reach the writing voltage for each color. In other words, when the field sequential method is adopted and black insertion driving is performed, a color filter is used for the counter substrate, and the liquid crystal display device is operated at a very high speed compared to a liquid crystal display device without black insertion driving. Need to drive. For this reason, there may occur a case where the voltage written to the display element of the pixel does not completely reach the writing voltage of each color for the reason of designing the liquid crystal display device such as increasing the number of pixels of the liquid crystal display panel.

  In the second embodiment, such a case will be described.

  In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The liquid crystal display device of the second embodiment is the same as the liquid crystal display device 1 of the first embodiment.

  That is, FIG. 1 is a block diagram showing the configuration of the liquid crystal display device 1 of the second embodiment.

  The backlight 11 is also shown in FIG. 2A and FIG. 2B as in the first embodiment.

  The optical sensor unit 26 is also shown in FIGS. 4 (a) and 4 (b), as in the first embodiment.

  Further, in the liquid crystal display device of the second embodiment, details of the illumination system such as the light control unit 18, the backlight control unit 19, and the backlight 11 are shown in FIG. 3 as in the first embodiment. .

  The backlight control unit 19 in FIG. 3 includes an analysis result storage unit 45, a calculation unit 46, and a time storage unit 47, which is the same as in the first embodiment. However, in the second embodiment, since the case where the voltage written to the display element of the pixel does not completely reach the write voltage of each color is handled, the information stored in the analysis result storage unit 45 is the first This is different from the embodiment.

  That is, the analysis result storage unit 45 according to the second embodiment is configured so that the writing voltage written to the pixel is the closest to the voltage corresponding to each color of the display data after the pixel starts writing. A semiconductor memory for storing time. The rest is the same as in the first embodiment.

  Next, the operation of the liquid crystal display device 1 of the second embodiment will be described, and an embodiment of the liquid crystal display device of the present invention will also be described.

  When the power source of the liquid crystal display device 1 is turned on, the liquid crystal display device 1 performs transfer driving in the same manner as the conventional liquid crystal display device 101 described in the background art.

  When the transfer driving is completed and the liquid crystal display device 1 can perform the display operation, the liquid crystal display device 1 starts the display operation.

  The operation in which the liquid crystal display device 1 writes the video display signal to the pixel has already been described in the first embodiment. That is, in one frame period (or one field period), a red display period, a black insertion period, a green display period, a black insertion period, a blue display period, and a black insertion period are provided in this order.

  Next, the operation of the illumination system such as the backlight 11 will be described.

  Note that the operation of the illumination system such as the backlight 11 will be described by focusing on the backlight block 15a constituting the backlight 11, as in the first embodiment, but also for the backlight blocks 15b to 15e. Since the operation is similar to that of the backlight block 15a, description of these operations is omitted.

  FIG. 11 shows voltage waveforms written in the display elements of the first pixel 78a, the middle pixel 78b, and the last pixel 78c shown in FIG. 6, and the ON / OFF states of the LEDs of the respective colors of the backlight block 15a. It is a timing chart figure. In FIG. 11, time elapses from the left side toward the right side as viewed in the drawing.

  Reference numeral 81a denotes a voltage waveform written to the display element of the first pixel 78a.

  81b is a voltage waveform written in the display element of the middle pixel 78b.

  81c is a voltage waveform written in the display element of the last pixel 78c.

  In FIG. 11, time has passed from the left side to the right side as viewed in the drawing.

  In FIG. 11, R_LED, G_LED, and B_LED indicate the ON / OFF states of the red LED, the green LED, and the blue LED among the LEDs 13a and 14a that are the light sources of the backlight block 15a, respectively, and the high state is ON. The Low state indicates that the light is off.

  In FIG. 11, 74 indicates a black voltage for black insertion driving, 71 indicates a voltage corresponding to red of display data, 72 indicates a red writing voltage to be written to the pixel in the red display period, and 72 indicates Indicates the voltage corresponding to the green color of the display data, indicates the green write voltage to be written to the pixel during the green display period, 74 indicates the voltage corresponding to the blue color of the display data, and indicates the blue write to be written to the pixel during the blue display period The voltage is shown.

  FIG. 11 shows a case where the light control unit 18 determines that the lighting ratios of the LEDs of the respective colors of the backlight block 15a are all 70%. That is, information that the lighting ratio of the LEDs of the LEDs 13a and 14a of the backlight 15a is 70% is stored in the lighting ratio storage unit 44 of the light control unit 18.

  The backlight control unit 19 reads this information from the lighting ratio storage unit 44 of the dimming unit 18, and further reads information stored in the analysis result storage unit 45.

  FIG. 12A shows information stored in the analysis result storage unit 45.

  In the middle pixel writing voltage closest approach time 45d, the voltage written to the display element of the middle pixel 78b after the writing of the voltage corresponding to each color of the display data is started to the display element of the first pixel 78a is This is the time required to approach the voltage corresponding to each color of the display data. In the last pixel threshold voltage arrival time 45e, the voltage written to the display element of the last pixel 78c after the start of writing of the voltage corresponding to each color of the display data to the display element of the first pixel 78a is changed to each color. Is a time required to reach a predetermined ratio with respect to the write voltage. In the first pixel threshold voltage leaving time 45f, the voltage written in the display element of the first pixel 78a after the voltage writing corresponding to each color of the display data is started on the display element of the first pixel 78a is changed to each color. This is the time to leave a predetermined ratio with respect to the write voltage.

  In the second embodiment, the voltage waveforms 81a, 81b, 81c written to the display element of the first pixel 78a, the display element of the middle pixel 78b, and the display element of the last pixel 78c are actually used as testers. By analyzing the measured voltage waveforms 81a, 81b, 81c, the middle pixel write voltage closest approach time 45d, the last pixel threshold voltage arrival time 45e, and the first pixel threshold voltage shown in FIG. The withdrawal time 45f was determined.

  Then, the calculated middle pixel write voltage closest approach time 45d, last pixel threshold voltage arrival time 45e, and first pixel threshold voltage departure time 45f are stored in advance in the analysis result storage unit 45 as shown in FIG. I remembered it.

  Then, the calculation unit 46 uses the backlight control signal (clock signal, horizontal synchronization signal, vertical synchronization signal, etc.) sent from the controller 4, and the middle pixel writing voltage closest approach time 45d, the last pixel threshold value By using the voltage arrival time 45e and the first pixel threshold voltage leaving time 45f, the lighting start timing and lighting end of each of the red LED, the green LED, and the blue LED of the LEDs 13a and 14a of the backlight block 15a are calculated. The time is determined and stored in the time storage unit 47. Note that how to calculate the lighting start time and the lighting end time by the calculation unit 46 will be described later.

  FIG. 12B shows the lighting start timing and lighting end timing of each of the red LED, the green LED, and the blue LED among the LEDs 13 a and 14 a of the backlight block 15 a stored in the timing storage unit 47. FIG. 12B is the same as FIG. 8B described in the first embodiment.

  The backlight control unit 19 turns on the red LED of the LEDs 13a and 14a of the backlight block 15a at the timing when the red LED lighting start time 47a stored in the time storage unit 47 is reached. Then, the red LED of the LEDs 13a and 14a of the backlight block 15a is turned off at the timing when the red LED lighting end timing 47b stored in the timing storage unit 47 is reached. The backlight control unit 19 performs the same control for the green LED and the blue LED among the LEDs 13a and 14a of the backlight block 15a.

  When the backlight control unit 19 performs such control, in FIG. 11, among the LEDs 13a and 14a that are the light sources of the backlight block 15a, the red LED, the green LED, and the blue LED are turned on / off. , R_LED, G_LED, B_LED.

  Now, as described above, how to calculate the lighting start time and the lighting end time by the calculation unit 46 will be described with reference to FIG.

  The calculation unit 46 reads from the lighting ratio storage unit 44 information that the lighting ratio of the LEDs 13a and 14a of the backlight block 15a is 70%. Next, the calculating part 46 calculates | requires the lighting period of red LED of LED13a of the backlight block 15a, 14a by multiplying a lighting ratio with respect to a red display period (red writing). The calculation unit 46 performs the same processing for green and blue, thereby obtaining the lighting periods of the LEDs 13a and 14a of the backlight block 15a and the blue LEDs.

  In addition, the lighting period of the red LED of this embodiment is an example of the predetermined lighting period of the present invention, and the lighting period of the green LED of this embodiment is an example of the predetermined lighting period of the present invention. The lighting period of the blue LED in this embodiment is an example of the predetermined lighting period of the present invention.

  Next, the calculation unit 46 uses the backlight control signal to determine the time when writing of the voltage corresponding to the red color of the display data is actually started on the display element of the first pixel 78a shown in FIG. At the determined time, the middle pixel writing voltage closest approach time 45d stored in the analysis result storage unit 45 is added. In this way, the time T20 when the write voltage waveform 81b of the display element of the middle pixel 78b is closest to the red write voltage 71 is obtained (see FIG. 11).

  The calculating unit 46 performs back-up so that the timing when the write voltage waveform 81b of the display element of the middle pixel 78b is closest to the red write voltage 71 coincides with the middle of the lighting period of the red LED. Of the LEDs 13a and 14a, which are the light sources of the light block 15a, the red LED lighting start time and the lighting end time are obtained and stored in the time storage unit 47 as the red LED lighting start time 47a and the red LED lighting end time 47b, respectively. (See FIG. 12B).

  The calculation unit 46 performs the same process on the green LED and the blue LED among the LEDs 13a and 14a that are the light sources of the backlight block 15a, thereby obtaining the time T21 and the time T22, thereby obtaining the time storage unit 47. The green LED lighting start timing 47c, the green LED lighting end timing 47d, the blue LED lighting start timing 47e, and the green LED lighting end timing 47f are stored in the timing storage unit 47.

  As the reference luminance stored in the reference value storage unit 40 in FIG. 3 is increased, the backlight control block 33a is dimmed by the dimming control unit 33, and as a result, is stored in the lighting ratio storage unit 44. The lighting ratio is also increased.

  In FIG. 11, even when the lighting ratio increases in this way, the upper limit of the lighting period of each color LED is limited as follows.

  That is, when the red LED is described, it is assumed that the calculation unit 46 determines the red LED lighting start timing 47a and the red LED lighting end timing 47b by the operation as described above.

  Thereafter, when the red LED lighting start time 47a starts to write the voltage corresponding to the red color of the display data to the display element of the first pixel 78a, the last pixel threshold voltage arrival time 45e (see FIG. 12). ) Is added (corresponding to time T20L in FIG. 11, hereinafter referred to as time T20L).

  If the red LED lighting start time 47a is smaller than the time T20L (past), the red LED lighting start time 47a is made equal to the time T20L and stored in the time storage unit 47.

  If the red LED lighting start timing 47a is equal to or greater than the timing T20L (future), the red LED lighting start timing 47a is stored in the timing storage unit 47 without being changed.

  Furthermore, when the red LED lighting end time 47b starts to write the voltage corresponding to the red color of the display data to the display element of the first pixel 78a, the first pixel threshold voltage leaving time 45f (see FIG. 12). ) Is added (corresponding to time T20U in FIG. 11, hereinafter referred to as time T20U).

  If the red LED lighting end time 47b is equal to or greater than the time T20U (future), the red LED lighting end time 47b is made equal to the time T20U and stored in the time storage unit 47.

  If the red LED lighting end time 47b is smaller than the time T20U (past), the red LED lighting end time 47b is stored in the time storage unit 47 without being changed.

  Similar processing is performed for the green LED and the blue LED.

  Thus, even when the lighting ratio is increased by limiting the upper limit of the lighting period of the red LED, the green LED, and the blue LED among the LEDs 13a and 14a that are the light sources of the backlight block, An increase in power consumption of each color LED can be suppressed, and a decrease in contrast can be suppressed.

  FIG. 13 shows a case where the light control unit 18 determines so that the lighting ratios of the LEDs of the respective colors of the backlight block 15a are all 100%. In other words, the lighting ratio storage unit 44 of the light control unit 18 stores information that the lighting ratios of the LEDs of the LEDs 13a and 14a of the backlight 15a are 100%. Even in such a case, by performing the same operation as described above, the calculation unit 46 can obtain the red LED lighting start timing 47a, the red LED lighting end timing 47b, and the like shown in FIG. 8B. I can do it.

  FIG. 14 shows a case where the light control unit 18 determines that the lighting ratios of the LEDs of the respective colors of the backlight block 15a are all 30%. That is, the lighting ratio storage unit 44 of the light control unit 18 stores information that the lighting ratio of the LEDs of the LEDs 13a and 14a of the backlight 15a is 30%. Even in such a case, by performing the same operation as described above, the calculation unit 46 can obtain the red LED lighting start time 47a, the red LED lighting end time 47b, and the like shown in FIG. I can do it.

  As shown in FIG. 14, even when the lighting ratio is lowered to 30%, that is, when the time during which the LEDs 13a and 14a of the backlight block 15a are lit is shortened, the middle scanning line 77b shown in FIG. The timings T20, T21, T22 at which the middle pixel 78b (see FIG. 6) approaches the red writing voltage 71, the green writing voltage 72, and the blue writing voltage 73 respectively coincide with the center of the lighting period of the backlight block 15a. . Then, the time when the first pixel 78a of the first scanning line 77a shown in FIG. 6 is closest to the red writing voltage 71, the green writing voltage 72, and the blue writing voltage 73, respectively, of the LEDs 13a and 14a of the backlight block 15a. It is included in the period when the red LED, the green LED, and the blue LED are lit. Similarly, when the last pixel 78c of the last scanning line 77c shown in FIG. 6 is closest to the red writing voltage 71, the green writing voltage 72, and the blue writing voltage 73, respectively, the LEDs 13a and 14a of the backlight block 15a. The red LED, the green LED, and the blue LED are included in a period for lighting. As shown in FIGS. 11 and 13, the same applies to the case where the lighting ratio is larger than that in FIG.

  Therefore, even when the voltage waveform written to the display element of the pixel is different from that of the first embodiment, the same effect as that of the first embodiment can be obtained.

  Further, in the liquid crystal display device 1 of the second embodiment, as shown in FIG. 14, when the lighting ratio is lowered to 30%, the time during which the LEDs 13a and 14a of the backlight block 15a are lit is shortened. Even in this case, display with high contrast can be performed.

  By utilizing this, the liquid crystal display device 1 of the second embodiment can be used for the purpose of efficiently lighting the LEDs 13a and 14a of the backlight block 15a.

  That is, by shortening the lighting time of the LEDs 13a and 14a of the backlight block 15a and increasing the voltage supplied to the LEDs 13a and 14a of the backlight block 15a, the LEDs 13a and 14a and the like emit light with high luminance. In this way, the liquid crystal display device 1 can perform high-contrast display and can be close to an impulse-type display such as a CRT, so that the video visibility can be improved and the power consumption can be further increased. Can also be reduced.

  In the second embodiment, the voltage waveforms 81a, 81b, 81c of the display elements of the first pixel 78a, the middle pixel 78b, and the last pixel 78c are actually measured, and the measured voltage waveforms 81a, 81b are measured. , 81c, the middle pixel writing voltage closest approach time 45d, the last pixel threshold voltage arrival time 45e, and the first pixel threshold voltage leaving time 45f shown in FIG. Not limited to this.

  The middle pixel writing voltage closest approach time 45d, the last pixel threshold voltage arrival time 45e, and the first pixel threshold voltage departure time 45f are voltages corresponding to the liquid crystal material used for the liquid crystal display panel 10 and black for black insertion driving. Is determined according to the timing of writing the first pixel 78a, the middle pixel 78b, and the last pixel 78c. Accordingly, the first pixel 78a, the middle pixel 78b, based on the timing of writing the liquid crystal material to be used and the voltage corresponding to black for black insertion driving to the first pixel 78a, the middle pixel 78b, the last pixel 78c, etc. The voltage waveform of the display element of the last pixel 78c is predicted, and the middle pixel writing voltage closest approach time 45d, the last pixel threshold voltage arrival time 45e, and the first pixel threshold voltage leaving time 45f are obtained in advance from the predicted voltage waveform. Is also possible.

  Further, in the second embodiment, the calculation unit 46 turns on the red LED at time T20, that is, when the write voltage waveform 81b of the display element of the middle pixel 78b is closest to the red write voltage 71. Although it has been described that the red LED lighting start timing and lighting end timing are obtained among the LEDs 13a and 14a that are the light sources of the backlight block 15a so as to coincide with the middle of the period, the present invention is not limited to this.

  The calculation unit 46 determines the magnitude and fall of the rising slope of the display element of the middle pixel 78b at the time T20, that is, the time when the write voltage waveform 81b of the display element of the middle pixel 78b is closest to the red writing voltage 71. Of the LEDs 13a and 14a, which are the light sources of the backlight block 15a, the red LED lighting start timing and lighting end timing may be corrected in accordance with the ratio to the magnitude of the inclination. Moreover, you may correct | amend the lighting start time and lighting end time of each of green LED and blue LED among LED13a and 14a which are the light sources of the backlight block 15a similarly to red LED.

  For example, in FIG. 14, the magnitude of the slope on the left side of the time T20 of the voltage waveform 81b is smaller than the magnitude of the slope on the right side of the time T20 of the voltage waveform 81b. In such a case, first, the timing T20, that is, the timing T20 at which the writing voltage waveform 81b of the display element of the middle pixel 78b is closest to the red writing voltage 71 coincides with the middle of the lighting period of the red LED. Furthermore, the lighting start timing and lighting end timing of the red LED among the LEDs 13a and 14a which are the light sources of the backlight block 15a are obtained.

  Thereafter, the lighting of the red LED determined in accordance with the ratio of the left slope (falling slope) of the voltage waveform 81b at the time T20 and the right slope (rising slope) of the time T20 is started. The timing and lighting end timing can be corrected.

  In the case of FIG. 14, the magnitude of the left slope (falling slope) at time T20 is smaller than the magnitude of the right slope (rise slope) at time T20. In such a case, in FIG. 14, the lighting start timing and lighting end timing of the red LED are set to the lighting start timing of the red LED in accordance with the ratio between the magnitude of the falling slope and the magnitude of the rising slope. And the lighting end time is shifted to the left side.

  In this way, the obtained lighting start timing and lighting end timing of the red LED are set to a ratio between the magnitude of the falling slope at time T20 of the voltage waveform 81b and the magnitude of the rising slope at time T20 of the voltage waveform 81b. It can be corrected accordingly. The same applies to the green LED and the blue LED among the LEDs 13a and 14a which are the light sources of the backlight block 15a.

  In this way, display with higher contrast becomes possible.

  As another method for obtaining the lighting start timing and lighting end timing of the red LED, the voltage waveform 81b in FIG. 14 is obtained by integrating the time from the lighting start timing of the red LED to the lighting end timing of the red LED. It is also possible to determine the lighting start timing and lighting end timing of the red LED so that the area to be taken has an extreme value. However, the length (time) of the section in which the voltage waveform 81b is integrated is matched with the lighting period of the red LED and integrated. The same applies to the green LED and the blue LED. Even in this case, high contrast display is possible as in the second embodiment.

  Such processing can also be applied to the voltage waveform 75b described with reference to FIG. 7 of the first embodiment. However, in the voltage waveform 75b, the extreme value may not be uniquely determined depending on the time length of the lighting period of the red LED. For example, as shown in FIG. 10, when the time length of the lighting period of the red LED is shortened, the extreme value may not be uniquely determined. As described above, when the extreme value is not uniquely determined, the lighting start timing and lighting end timing of the red LED may be determined by the method described in the first embodiment.

  In this way, the lighting of the red LED is started so that the area obtained by integrating the voltage waveform 81b and the voltage waveform 75b with the time from the lighting start timing of the red LED to the lighting end timing of the red LED becomes an extreme value. By determining the timing and the lighting end timing, and performing the same processing for the green LED and the blue LED, it is possible to display high contrast as in the first and second embodiments. .

  Further, in the first and second embodiments, the OCB mode liquid crystal is used for the liquid crystal layer of the liquid crystal display panel 10, but a liquid crystal other than the OCB mode liquid crystal may be used. For example, a TN (twisted nematic) type liquid crystal layer, an STN (Super-Twisted Nematic) mode liquid crystal layer, a DSM (Dynamic Scattering Mode) liquid crystal layer, an ECB (Electrically Controlled Birefringence mode). ) Liquid crystal layer, VA (Vertically Aligned) mode liquid crystal layer, or the like may be used. In order to bring the liquid crystal display panel 10 closer to an impulse-type display such as a CRT, it is more preferable to use a liquid crystal having high-speed response.

  Furthermore, as described above, the liquid crystal display device 1 of the first embodiment and the liquid crystal display device 1 of the second embodiment are similar to the conventional liquid crystal display device 101 in the OCB mode liquid crystal display element. It has been described as a field sequential type liquid crystal display device using the above. That is, it is preferable to use an OCB mode liquid crystal display element in terms of high-speed response than to use a TN (Twisted Nematic) alignment liquid crystal display panel.

  However, this means that, as described above, the liquid crystal display panel 10 of the liquid crystal display device 1 of the first embodiment or the liquid crystal display panel 10 of the second embodiment uses OCB mode liquid crystal. In addition, the liquid crystal display panel 10 of the liquid crystal display device 1 of the first embodiment or the liquid crystal display panel 10 of the second embodiment is a field sequential type liquid crystal display panel. It is not limited.

  As the liquid crystal display panel 10 of the liquid crystal display device 1 of the first embodiment or the liquid crystal display panel 10 of the liquid crystal display device 1 of the second embodiment, a TN (Twisted Nematic) alignment liquid crystal display panel or the like is used to prevent reverse transition. The first embodiment and the second embodiment described above can also be applied to the case where black insertion driving is performed using a liquid crystal display panel using a liquid crystal layer that does not require driving as described below.

  That is, in the case of such a liquid crystal display device, it is not necessary to perform the transfer driving described in the first embodiment and the second embodiment. The rest is the same as in the first embodiment or the second embodiment.

  Needless to say, the first embodiment and the second embodiment can be applied to a liquid crystal display device in which a color filter is formed on a counter substrate, instead of the field sequential method.

In the case of such a liquid crystal display device, in the above description, it is read that one frame (or one field period) is composed of a red display period (red writing) and a subsequent black insertion period (black writing). Further, if the red display period (red writing) is replaced with the display period (color writing), the above description can be applied as it is.

  Further, in the liquid crystal display device 1 of the first embodiment and the liquid crystal display device 1 of the second embodiment, the liquid crystal display panel is arranged in the order of red writing, black insertion, green writing, black insertion, blue writing, and black insertion. However, the present invention is not limited to this.

  The first embodiment and the second embodiment can also be applied when driving the liquid crystal display panel 10 in the order of red writing, green writing, blue writing, and black insertion. In this way, by reducing the black insertion period once in one frame (or one field) period, each period of red writing, green writing, and blue writing can be lengthened, so that high luminance display is possible. become.

  Also, when black insertion is performed only once before (past) or behind (future) any one of red writing, green writing, and blue writing, high-luminance display can be performed as described above. Further, when black insertion is performed in any two periods of red writing, green writing, and blue writing, high-luminance display can be performed in the same manner as described above.

  Further, when performing field sequential display using a liquid crystal display panel using a liquid crystal layer that does not require reverse transition prevention driving, such as a TN (twisted nematic) alignment liquid crystal display panel, that is, red writing, green writing, blue The first embodiment and the second embodiment can also be applied when the liquid crystal display panel 10 is driven in the order of writing and black insertion is not performed.

  In the first embodiment or the second embodiment, when the light control is performed, the optical sensor unit 26 is arranged so as to match the luminance and / or chromaticity stored in the reference value storage unit 40. Although it has been described that dimming is performed by varying the lighting ratio using the detected luminance of each color, in addition to the dimming operation described in the first embodiment or the second embodiment, By using a dimming operation as described below in combination, more precise dimming is possible.

  First, as described in the first embodiment and the second embodiment, the first dimming method determines the red LED lighting start timing 47a, the red LED lighting end timing 47b, etc. This is a method in which the voltage supplied for lighting the red LED is kept constant during the lighting period of the LED, and the current is varied. The same operation is performed for the green LED and the blue LED.

  The second dimming method determines the red LED lighting start timing 47a, the red LED lighting end timing 47b, etc. as described in the first embodiment and the second embodiment, and then red. This is a method of changing the voltage while keeping the current supplied for lighting the red LED constant during the lighting period of the LED. The same operation is performed for the green LED and the blue LED.

  The third dimming method determines the red LED lighting start timing 47a, the red LED lighting end timing 47b, etc., as described in the first and second embodiments, This is a method in which both the current and voltage supplied to light the red LED are varied during the lighting period of the LED. The same operation is performed for the green LED and the blue LED.

  The fourth dimming method determines the red LED lighting start timing 47a, the red LED lighting end timing 47b, etc., as described in the first embodiment and the second embodiment, and then red. This is a method of performing PWM (Pulse Width Modulation) control of a red LED with a very short period (very high frequency) compared to the lighting period of the red LED during the lighting period of the LED. The same operation is performed for the green LED and the blue LED.

  By combining the first to fourth dimming methods with the dimming method in the first embodiment or the second embodiment, more precise control of luminance, luminance difference, and contrast becomes possible.

  Furthermore, in the first embodiment and the second embodiment, the dimming control unit 33 determines the lighting ratio based on the reference luminance and / or luminance stored in the reference value storage unit 40. And stored in the lighting ratio storage unit 44. And based on the lighting ratio memorize | stored in the lighting ratio memory | storage part 44, the calculating part 46 determines the lighting period of LED of each color, and also the lighting start time and lighting end time about the determined lighting period of LED of each color However, the present invention is not limited to this.

  For example, in the first embodiment, the red display in FIG. 7 will be described. When the calculation unit 46 determines the time (T1 + T2) / 2 in FIG. 7, the determined time (T1 + T2) / 2 is set. Hold. Then, the calculation unit 46 may determine the red LED lighting start time 47a and the red LED lighting end time 47b with reference to the held time (T1 + T2) / 2. The same applies to the green LED and the blue LED. As described above, once the time (T1 + T2) / 2 is determined, it is necessary to calculate the time (T1 + T2) / 2 again every frame (or one field) period by holding the time. Therefore, the calculation amount in the calculation unit 46 can be reduced.

  In the second embodiment, the display of red in FIG. 11 will be described. When the calculation unit 46 determines the time T20 in FIG. 11, the determined time T20 is held. Then, the calculation unit 46 may determine the red LED lighting start time 47a and the red LED lighting end time 47b with reference to the held time T20. The same applies to the green LED and the blue LED. As described above, once the time T20 is determined, the time T20 is held, so that it is not necessary to recalculate the time T20 or the like every frame (or one field) period. Can be reduced.

  Further, in the first and second embodiments, the light source of the backlight 11 has been described as the LEDs 13a to 13e and 14a to 14e. However, the present invention is not limited to this, and a cold cathode tube is used as the light source of the backlight 11. It doesn't matter. Further, a display device using an EL element may be used as the light source of the backlight 11. In short, it is only necessary to use a light source having high-speed response as the light source of the backlight 11.

  Further, in the first and second embodiments, it has been described that one LED is provided as a light source of the backlight 11 on each side of each backlight block, but the present invention is not limited to this. Each backlight block may be provided on one side. In this case, the optical sensor unit 26 may be provided on the side opposite to the side where the LEDs are provided.

  Furthermore, in the first and second embodiments, the backlight 11 is divided into five backlight blocks 15a to 15e. However, the present invention is not limited to this. The backlight 11 may not be divided into a plurality of backlight blocks, but may be composed of only one backlight. Further, the backlight 11 may be divided into two or more backlight blocks, and may be divided into at least the number of backlight blocks equal to the number of pixels (the number of scanning lines) in the vertical direction of the liquid crystal display panel. . Note that the number of backlights equal to the number of scanning lines from about 1/5 of the number of pixels in the vertical direction of the liquid crystal display panel (the number of scanning lines) can be configured using, for example, an EL display device. It is.

  The program of the present invention is a program for causing a computer to execute the functions of all or part of the liquid crystal display device of the present invention described above, and is a program that operates in cooperation with the computer.

  The recording medium of the present invention is a recording medium that records a program for causing a computer to execute all or part of the functions of the liquid crystal display device of the present invention described above. It is a recording medium that can be read and the read program executes the function in cooperation with the computer.

  In addition, the above-mentioned “parts and the like” of the present invention means one or several parts of the plurality of parts.

  Further, the above-mentioned “functions of the parts” of the present invention means functions of all or a part of the parts.

  Further, one use form of the program of the present invention may be an aspect in which the program is recorded on a recording medium such as a ROM readable by a computer and operates in cooperation with the computer.

  Also, one use form of the program of the present invention is an aspect in which the program is transmitted through a transmission medium such as the Internet, a transmission medium such as light, radio wave, and sound wave, read by a computer, and operates in cooperation with the computer. Also good.

  The computer of the present invention described above is not limited to pure hardware such as a CPU, but may include firmware, an OS, and peripheral devices.

  As described above, the configuration of the present invention may be realized by software or hardware.

  The liquid crystal display device, the driving method of the liquid crystal display device, the program, and the recording medium according to the present invention have an effect that images can be displayed with good contrast, and can be intermittently lit intermittently. It is useful for a liquid crystal display device having a backlight for illuminating a liquid crystal display panel, a driving method of the liquid crystal display device, a program, a recording medium, and the like.

  The liquid crystal display device, the driving method of the liquid crystal display device, the program, and the recording medium according to the present invention have an effect of suppressing the occurrence of a luminance difference depending on the location of the display screen, and intermittently light up intermittently. The present invention is useful for a liquid crystal display device including a backlight that can be lit and illuminating a liquid crystal display panel, a driving method of the liquid crystal display device, a program, a recording medium, and the like.

  The liquid crystal display device, the driving method of the liquid crystal display device, the program, and the recording medium according to the present invention have an effect that a high-luminance display corresponding to the backlight lighting period and the luminance is possible, and is intermittent. This is useful for a liquid crystal display device having a backlight for illuminating a liquid crystal display panel, a driving method of the liquid crystal display device, a program, a recording medium, and the like.

  The liquid crystal display device, the driving method of the liquid crystal display device, the program, and the recording medium according to the present invention can freely adjust the contrast level of the display screen of the display panel, the magnitude of the luminance, and the degree of the luminance difference as designed values. A liquid crystal display device having a backlight for illuminating a liquid crystal display panel, a liquid crystal display device driving method, a program, a recording medium, and the like Useful for.

The block diagram which shows the structure of the liquid crystal display device in the 1st and 2nd embodiment of this invention (A) A plan view showing an outline of a backlight used in the liquid crystal display device according to the first and second embodiments of the present invention. (B) The liquid crystal display device according to the first and second embodiments of the present invention. Side view showing the outline of the backlight used The block diagram which shows the detailed structure of the illumination system of the liquid crystal display device in the 1st and 2nd embodiment of this invention (A) The top view which shows the outline | summary of the optical sensor part used for the liquid crystal display device in the 1st and 2nd embodiment of this invention (b) The liquid crystal display device in the 1st and 2nd embodiment of this invention Sectional view showing the outline of the optical sensor used in Equivalent circuit showing the configuration of the pixel of the liquid crystal display device in the first and second embodiments of the present invention The figure which shows the relationship between the backlight block in the 1st and 2nd embodiment of this invention, and the part of the display area of the liquid crystal display panel facing a backlight block. The voltage written in the display element of the specific pixel on the specific scan line among the scan lines existing in the display area of the liquid crystal display panel facing the backlight block of the liquid crystal display device in the first embodiment of the present invention Timing chart showing waveforms and lighting / unlit state of each color of backlight block (A) The figure which shows the information memorize | stored in the analysis result memory | storage part in the 1st Embodiment of this invention (b) The information memorize | stored in the time memory | storage part in the 1st Embodiment of this invention is shown Figure The voltage written in the display element of the specific pixel on the specific scan line among the scan lines existing in the display area of the liquid crystal display panel facing the backlight block of the liquid crystal display device in the first embodiment of the present invention Timing chart showing waveforms and lighting / unlit state of each color of backlight block The voltage written in the display element of the specific pixel on the specific scan line among the scan lines existing in the display area of the liquid crystal display panel facing the backlight block of the liquid crystal display device in the first embodiment of the present invention Timing chart showing waveforms and lighting / unlit state of each color of backlight block The voltage written in the display element of the specific pixel on the specific scan line among the scan lines existing in the display area of the liquid crystal display panel facing the backlight block of the liquid crystal display device according to the second embodiment of the present invention Timing chart showing waveforms and lighting / unlit state of each color of backlight block (A) The figure which shows the information memorize | stored in the analysis result memory | storage part in the 2nd Embodiment of this invention (b) The information memorize | stored in the time memory | storage part in the 2nd Embodiment of this invention is shown Figure The voltage written in the display element of the specific pixel on the specific scan line among the scan lines existing in the display area of the liquid crystal display panel facing the backlight block of the liquid crystal display device according to the second embodiment of the present invention Timing chart showing waveforms and lighting / unlit state of each color of backlight block The data is written in the display element of a specific pixel on a specific scanning line among the scanning lines existing in the display area of the liquid crystal display panel facing the backlight block of the liquid crystal display device according to the second embodiment of the present invention. Timing chart showing the voltage waveform and the lighting / extinguishing state of each color of the backlight block (A) It is sectional drawing which showed typically the orientation state of the liquid crystal molecule which the display element of OCB mode has, and is sectional drawing which shows a voltage application state (b) The orientation state of the liquid crystal molecule which the display element of OCB mode has typically (C) A cross-sectional view schematically showing an alignment state of liquid crystal molecules included in an OCB mode display element, and showing a state in which no voltage is applied. Figure Block diagram showing the configuration of a conventional liquid crystal display device FIG. 5 is a timing chart showing voltage waveforms written in display elements of specific pixels of the conventional liquid crystal display device 101 and lighting / lighting states of the respective colors of the backlight 111.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Source driver 3 Gate driver 4 Controller 10 Liquid crystal display panel 11 Backlight 13a, 13b, 13c, 13d, 13e LED
14a, 14b, 14c, 14d, 14e LED
15a, 15b, 15c, 15d, 15e Backlight block 16 Input power supply 17 Liquid crystal drive voltage generation circuit 18 Dimming unit 19 Backlight control unit 21 Signal processing unit 23 Timing control unit 24 D / A conversion unit 25 Shift register 33 Dimming Control unit 40 Reference value storage unit 44 Lighting ratio storage unit 45 Analysis result storage unit 46 Calculation unit 47 Timing storage unit

Claims (15)

A liquid crystal display panel having signal lines and scanning lines formed in a matrix, and liquid crystal display elements formed corresponding to the intersections of the signal lines and the scanning lines;
A source driver that applies an applied voltage corresponding to display data to a signal line of the liquid crystal display panel;
Intermittent lighting that is intermittently lit is possible, a backlight that illuminates the liquid crystal display panel,
Based on the voltage in which the applied voltage is written to the liquid crystal display element via the signal line, the lighting disclosure timing, the lighting end timing, and the middle of the predetermined lighting period for the predetermined lighting period of the backlight A liquid crystal display device comprising: a backlight control unit that determines at least one of the times. The liquid crystal display panel has a storage capacity for each liquid crystal display element,
The voltage in which the applied voltage is written to the liquid crystal display element via the signal line is a voltage in which the applied voltage held in the storage capacitor via the signal line is written to the liquid crystal display element. The liquid crystal display device according to claim 1.   When the voltage written in the liquid crystal display element reaches the applied voltage, the backlight control unit determines that the middle period of the predetermined lighting period is (1) last in one frame period or one field period. The time when the voltage written in the liquid crystal display element existing on the scanning line to be scanned reaches the applied voltage, and (2) the liquid crystal display existing on the scanning line which is first scanned in one frame period or one field period The liquid crystal display device according to claim 2, wherein the lighting start time and the lighting end time are determined so that a voltage written in the element coincides with a middle time from a time when the voltage leaves the applied voltage.   When the voltage written to the liquid crystal display element does not reach the applied voltage, the backlight control unit writes the middle time of the predetermined lighting period to the liquid crystal display element existing on the middle scanning line. 3. The liquid crystal display device according to claim 2, wherein the lighting start time and the lighting end time are determined so as to coincide with a time when the applied voltage is closest to the applied voltage.   The backlight control unit corrects the lighting start timing and the lighting end timing according to a ratio between the rising slope magnitude and the falling slope magnitude of the voltage written to the liquid crystal display element. The liquid crystal display device according to claim 4.   The backlight control unit includes the lighting start timing and the lighting end timing so that an area obtained by integrating the voltage written in the liquid crystal display element from the lighting start timing to the lighting end timing takes an extreme value. The liquid crystal display device according to claim 2, wherein:   The liquid crystal display device according to claim 2, wherein the predetermined lighting period is variable. The liquid crystal display panel uses OCB mode liquid crystal,
The liquid crystal display panel performs color display with temporal additive color mixing,
The source driver applies the applied voltage corresponding to the color of display data to the signal line during a display period for each color provided within a period of one frame or one field, and after the display period of each color A black applied voltage corresponding to black is applied to the signal line during each black insertion period provided,
During the display period for each color, the backlight is turned on for a predetermined lighting period based on the degree of the voltage at which the applied voltage held in the storage capacitor is written to the liquid crystal display element via the signal line. The liquid crystal display device according to claim 2, wherein at least one of a disclosure time, a lighting end time, and a middle time of the predetermined period is determined.   The liquid crystal display device according to claim 8, wherein the display period for each color is a red display period for displaying red, a green display period for displaying green, and a blue display period for displaying blue. The backlight is divided into a plurality of backlight blocks in parallel to the scanning lines,
The source driver applies an applied voltage corresponding to display data to the signal line during a display period provided within a period of one frame or one field, and turns black during a black insertion period provided after the display period. A corresponding black applied voltage is applied to the signal line,
The backlight control unit, when the portion of the display area of the liquid crystal display panel facing each divided backlight block is the black insertion period, removes the backlight block from the predetermined lighting period. The liquid crystal display device according to claim 2, wherein the liquid crystal display device is turned off.   When the voltage written in the liquid crystal display element reaches the applied voltage, the backlight control unit is configured such that for each of the backlight blocks, the middle period of the predetermined lighting period is (1) 1 frame. A period when the voltage written in the liquid crystal display element existing on the scanning line last scanned for the backlight block in the period or one field period reaches the applied voltage; and (2) in one frame period or one field period. The lighting start of the backlight block is performed so that the voltage written in the liquid crystal display element existing on the scanning line that is scanned first for the backlight block coincides with the middle of the time when the voltage deviates from the applied voltage. The liquid crystal display device according to claim 10, wherein a timing and a lighting end timing are determined.   When the voltage written in the liquid crystal display element does not reach the applied voltage, the backlight control unit, for each of the backlight blocks, the middle time of the predetermined lighting period of the backlight block, The lighting block start timing and the lighting end timing are set so that the voltage written in the liquid crystal display element existing on the scanning line in the middle of the backlight block coincides with the timing when the applied voltage is closest. The liquid crystal display device according to claim 10, which is determined. A liquid crystal display panel having signal lines and scanning lines formed in a matrix, and liquid crystal display elements formed corresponding to the intersections of the signal lines and the scanning lines;
A source driver that applies an applied voltage corresponding to display data to a signal line of the liquid crystal display panel;
A method of driving a liquid crystal display device that can be intermittently lit intermittently and drives a liquid crystal display device including a backlight that illuminates the liquid crystal display panel,
Based on the degree of voltage at which the applied voltage is written to the liquid crystal display element via the signal line, the lighting disclosure timing, the lighting end timing, and the predetermined lighting period of the predetermined lighting period of the backlight. A method for driving a liquid crystal display device, comprising a backlight control step for determining at least one of the middle periods.   The liquid crystal display device according to claim 1, wherein a lighting disclosure timing for a predetermined lighting period of the backlight, lighting based on a degree of voltage in which the applied voltage is written to the liquid crystal display element via the signal line. A program for causing a computer to function as a backlight control unit that determines at least one of an end time and a middle time of the predetermined lighting period.   A recording medium on which the program according to claim 14 is recorded, wherein the recording medium can be processed by a computer.

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