JP2007322945A - Display control device, display device, and display control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display control device for suppressing displayed chromaticity change and reducing power consumption, and also to provide a display device, and a display control method thereof. <P>SOLUTION: A calculation part 45 calculates current values to be applied to respective LED elements 31(R), 31(G) and 31(B) so as to obtain brightness of a set backlight 42. For instance, when being changed from first brightness to second higher brightness than it, the calculation part 45 sets so as to raise the current values of respective LED elements 31(R), 31(G) and 31(B). The calculation part 45 calculates chromaticity change equivalent to brightness change from the first brightness to the second brightness when setting the second brightness for instance. The calculation part 45 calculates a ratio of the current value of each LED element 31(R), 31(G), and 31(B) for compensating the chromaticity change so as to cancel the calculated chromaticity change. Each LED element is driven by the ratio of the calculated current quantity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a display device that displays an image by controlling the transmittance of a backlight, a display control device that controls the display device, and a control method therefor.
About.

  In a display device that controls the light transmittance and displays an image, for example, a liquid crystal display device, since a pixel of the liquid crystal panel does not emit light, a backlight is disposed on the back side of the liquid crystal panel, and the backlight uses the backlight of the liquid crystal panel. The back is illuminated to display the image. Recently, an LED (Light Emitting Diode) is often used as the backlight.

  In such an LED backlight, luminance control is performed by PWM (Pulse Width Modulation) driving (see, for example, Patent Document 1). This is to prevent a change in chromaticity caused by a change in the light emission wavelength of the LED by simple current driving.

JP 2006-30309 A (paragraph [0023], FIG. 5)

  However, although the device of Patent Document 1 can solve the change in chromaticity, in the PWM drive, since the nonlinearity of the power-luminance characteristic is significant, for example, a luminance twice as high as a certain luminance (hereinafter referred to as “single luminance”) is obtained. In order to obtain it, it is necessary to input about three times as much power. For this reason, for example, in order to enable driving up to twice the luminance in accordance with the video signal, it is necessary to always give the peak power three times. In this case, in the case of 1 × luminance, it is driven with a duty ratio of 50%, but eventually, an average 1.5 times (3 × 50%) of power is required, resulting in a significant power consumption loss. Will bring. Therefore, in practice, it becomes difficult to realize a peak luminance that varies greatly.

  On the other hand, when current driving is simply performed instead of PWM driving, such a problem of power loss is eliminated, but in this case, as described above, the emission wavelength of the LED changes depending on the current. As a result, there is a problem that the chromaticity displayed on the display screen changes.

  In view of the circumstances as described above, an object of the present invention is to provide a display control device, a display device, and a display control method capable of reducing power consumption and suppressing a change in displayed chromaticity. There is.

  In order to achieve the above object, a display control apparatus according to the present invention includes a backlight having an LED element, luminance setting means for setting the luminance of the backlight, and the LED element to obtain the set luminance. By controlling the amount of current applied, there are provided current driving means for driving the backlight, and compensation means for compensating for chromaticity changes according to changes in the current amount by the current driving means.

  In the present invention, the brightness of the backlight is controlled by controlling the amount of current applied to the LED element by the current driving means, so that power consumption can be reduced. Further, although the emission wavelength of the LED element changes due to the change in the amount of current, the change in chromaticity at that time is compensated by the compensation means, and the change in chromaticity can be suppressed.

  In the present invention, the backlight includes LED elements of three primary colors, and the compensation means includes current ratio control means for controlling a ratio of current amounts applied to the LED elements by the current driving means. Have. That is, by controlling the ratio of each current amount applied to each LED element so as to compensate for the chromaticity change, it is possible to suppress the chromaticity change in the vicinity of white where the three primary colors are combined. Since the color most sensitive to human vision is near white, there is no problem if the change in chromaticity near white is suppressed.

  In the present invention, the backlight is a backlight having a plurality of pixels respectively corresponding to the three primary colors, and irradiating the display device that changes the light transmittance for each pixel, and the compensation means Drive signal ratio control means for controlling a ratio of magnitudes of drive signals applied to the respective pixels corresponding to the three primary colors. That is, the change in the chromaticity can be suppressed by controlling the ratio of the magnitude of the drive signal applied to each pixel of the display device so as to compensate for the chromaticity change. In the case of the present invention, it is possible to compensate not only in the vicinity of white but also in all chromaticities as described above. Therefore, for example, the compensation for the chromaticity change near white is performed by the current ratio control means, and the compensation for the chromaticity change other than the vicinity of white is performed by the drive signal ratio control means.

  “Pixels” here are so-called sub-pixels, and are three pixels corresponding to the three primary colors red, green and blue, respectively.

  Alternatively, in the present invention, the current ratio control means may not be provided, and the drive signal ratio control means may compensate for all chromaticity changes including the vicinity of white.

  In the present invention, the display control device includes a PWM driving unit that drives the backlight by a PWM method so as to obtain the set luminance, luminance control of the backlight by the current driving unit, and the PWM driving unit. And a switching means for switching between brightness control of the backlight. Thus, by providing the switching means for switching between the current driving means and the PWM driving means, one can be appropriately selected as necessary, and balanced display control is performed so as to minimize power consumption. It becomes possible.

  In the present invention, the switching unit is driven by the PWM driving unit when the luminance set by the luminance setting unit is less than or equal to a predetermined value, and when the set luminance exceeds the predetermined value, Driven by current drive means. As a result, when displaying an image with relatively high luminance (brightness higher than a predetermined value), it is driven by switching to the current driving means, so that the chromaticity change is compensated and the luminance is relatively high. Even power consumption can be reduced.

  A display control apparatus according to another aspect of the present invention is a display control apparatus for a display device that displays an image according to an input video signal on a display screen by changing light transmittance for each of a plurality of pixels. A backlight having a LED element that emits the light, and a plurality of light source blocks that are arranged corresponding to a plurality of regions that are configured by the LED elements and into which the display screen is divided, and each of the light source blocks. Storage means for storing display luminance contribution ratio data for each region of the display screen when emitting light, detection means for detecting display luminance of the display screen by the video signal, and the stored contribution ratio Luminance distribution setting means for setting the light emission luminance distribution of each light source block according to the detected display luminance using the data, and the LE so as to obtain the set luminance distribution By controlling the amount of current applied to the device, comprising a current driving means for driving the backlight, and a compensating means for compensating the chromaticity change according to the change of the current amount by the current driving means.

  One light source block among the plurality of light source blocks may be composed of one LED element, or may be composed of a plurality of LED elements. Actually, it is desirable that one light source block is composed of a plurality of LED elements.

  In the present invention, a plurality of light source blocks are arranged corresponding to each area of the display screen, and the luminance of each light source block is individually controlled (hereinafter referred to as partial driving). As a result, the luminance is controlled as necessary for each region, so that power consumption is reduced. Further, the light emission luminance distribution of each light source block is set using the data of the contribution ratio of the display luminance with respect to each area of the display screen. That is, since the influence of each of the light source blocks on each area of the display screen is taken into consideration, the original image can be faithfully reproduced.

  Further, in the present invention, the luminance of the backlight is controlled by controlling the amount of current applied to the LED element by the current driving unit as described above. Electric power can be realized. Furthermore, although the light emission wavelength of the LED element changes due to the change in the amount of current, the change in chromaticity at that time is compensated by the compensation means, and the change in chromaticity can be suppressed.

  In the present invention, by providing the switching means for switching between the current driving means and the PWM driving means described above, it is further advantageous when, for example, there is a region having a relatively high display luminance among the respective regions. Become.

  A display device according to the present invention includes a plurality of pixels, a display device that displays an image by changing light transmittance for each of the pixels, a backlight having an LED element that emits the light, and the backlight. By brightness setting means for setting the brightness of the light, current drive means for driving the backlight by controlling the amount of current applied to the LED element so as to obtain the set brightness, and by the current drive means Compensation means for compensating for a change in chromaticity according to a change in the amount of current.

  A display device according to another aspect of the present invention includes a plurality of pixels and a display screen including the pixels, and an input video signal by changing light transmittance for each pixel. A display device that displays an image corresponding to the display screen, an LED element that emits the light, and a plurality of light source blocks that are configured by the LED element and are arranged corresponding to a plurality of regions into which the display screen is divided And a storage means for storing data of a contribution ratio of display luminance with respect to each area of the display screen when each light source block emits light, and display luminance of the display screen by the video signal. Detecting means for detecting, luminance distribution setting means for setting a light emission luminance distribution of each of the light source blocks according to the detected display luminance, using the stored contribution rate data; By controlling the amount of current applied to the LED element so as to obtain a luminance distribution, current driving means for driving the backlight, and chromaticity change according to the change in the current amount by the current driving means Compensation means for compensating.

  The display control method according to the present invention includes a step of setting the luminance of a backlight having LED elements, and the amount of current applied to the LED elements so as to obtain the set luminance, thereby controlling the backlight. A step of driving, and a step of compensating for a change in chromaticity according to a change in the amount of current.

  A display control method according to another aspect of the present invention includes a plurality of pixels and a display screen configured by each of the pixels, and an input image by changing light transmittance for each of the pixels. A display device that displays an image corresponding to a signal on the display screen, a plurality of light source blocks that are configured to correspond to a plurality of regions in which the display screen is divided, the LED element emitting light, and the LED element. A display control method for a display device comprising: a backlight comprising: a step of storing contribution data of display luminance with respect to each region of the display screen when each light source block emits light; Detecting the display brightness of the display screen by the video signal, and using the stored contribution rate data, the light emission brightness of each light source block according to the detected display brightness A step of setting a cloth, a step of driving the backlight by controlling an amount of current applied to the LED element so as to obtain the set luminance distribution, and chromaticity according to a change in the amount of current Compensating for the change.

  As described above, according to the present invention, it is possible to reduce power consumption and to suppress a change in displayed chromaticity.

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

  FIG. 1 is a schematic diagram showing a display device according to an embodiment of the present invention. The display device 10 is a liquid crystal display device in which liquid crystal is mounted as a device that changes the light transmittance for each pixel, for example.

  The liquid crystal display device 10 controls the liquid crystal display device 11 that displays an image, the backlight 42 disposed on the back side of the liquid crystal display device 11, and various controls for the backlight 42 and the liquid crystal display device 11. Unit 20 and a memory 16 accessible by the control unit 20. The control unit 20 includes a backlight lighting control circuit 15 that controls lighting of the backlight 42 and a liquid crystal panel control circuit 14 that controls driving of the liquid crystal panel 13 of the liquid crystal display device 11.

  The liquid crystal display device 11 has a source driver 17 and a gate driver 18 for sending drive signals to the liquid crystal panel 13.

  FIG. 2 is a diagram illustrating an example of a single cell in which RGB LED elements constituting the backlight 42 are arranged. As shown in FIG. 1, the single cell 30 includes a red (R) LED element 31 (R), a green (G) LED element 31 (G), and a blue (B) LED element 31 (B). Each of the two is connected in series with their polarities aligned in one direction, and is composed of a total of six LED elements.

  The unit cell 30 has six configurations in this example. However, the light output balance needs to be adjusted in order to make the mixed color a balanced white light according to the rating of the LED element to be used and the light emission efficiency. Therefore, the number distribution of each color may have a configuration example other than the present embodiment.

  A plurality of single cells 30 are connected to form a backlight 42, but the junction between the single cells 30 is arranged in the center as shown in FIG. 2 so that the polarities of the LED elements of each color are aligned in one direction. Connected by double-ended arrows. FIG. 3 shows an equivalent diagram of FIG.

  The backlight 42 includes a plurality of single cells 30 shown in FIG. In the example shown in FIG. 1, a plurality of blocks represented by “6G6R6B” are arranged vertically and horizontally. Hereinafter, this one block is referred to as a “light source block”. The backlight 42 is configured by arranging 5 × 4 = 20 light source blocks 40. “6G6R6B” means that each of the RGB LED elements 31 (R), 31 (G), and 31 (B) is provided in six by connecting three single cells 30 in cascade. To do. That is, one light source block 40 includes three single cells 30 and a total of 18 LED elements, and the backlight 42 includes 360 LED elements.

  The light emitted from each light source block 40 is diffused by a scattering plate or a scattering sheet (not shown) and applied to the back surface of the liquid crystal panel 13.

  Note that the number of single cells 30 included in one light source block is not three, but may be one or four or more.

  The number of light source blocks 40 included in the backlight 42 can be changed as appropriate. As will be described later, when the backlight 42 is controlled so as to maintain uniform luminance, the number of the light source blocks 40 may be simply one. In addition, the backlight 42 is configured to be arranged in a matrix in the XY direction (vertical and horizontal directions), but may be configured to be disposed only in one of the X direction and the Y direction. In this case, one light source block 40 is configured to be vertically long or horizontally long as illustrated.

  FIG. 4 is a diagram showing the configuration of the backlight lighting control circuit 15 and the backlight 42. The backlight lighting control circuit 15 includes a calculation unit 45, a power supply unit 43, and current amount control elements 44 (R), 44 (G), and 44 (B).

  The power supply unit 43 includes a power supply unit 43 that individually supplies power to each light source block 40 by setting a power supply voltage supplied from a primary power supply (not shown) to a predetermined constant voltage. The power supply unit 43 is configured by a switching regulator, for example. Current amount control elements 44 (R), 44 (G), and 44 (B) are provided for each light source block 40, and each LED element 31 (R), 31 (G), and 31 (B) of the light source block 40 is provided. It is an element that controls the amount of applied current. The current amount control elements 44 (R), 44 (G), and 44 (B) are configured by, for example, FETs (Field Effect Transistors), variable resistance elements, or the like. The calculation unit 45 sets the luminance of the backlight 42 according to the external signal.

  The external signal is, for example, an arbitrary luminance setting signal by the user of the liquid crystal display device 10, a detection signal by a sensor (not shown), a video signal shown in FIG. The sensor is, for example, an illuminance sensor that detects the ambient brightness on which the liquid crystal display device 10 is placed. For example, the calculation unit 45 sets a predetermined luminance according to the ambient brightness. The external signals are not limited to these, and various other signals can be considered.

  In the present embodiment, the calculation unit 45 sets so that the luminance of all the light source blocks 40 is uniform (constant). However, the calculation unit 45 can also be set so that the luminance is individually changed for each of the plurality of light source blocks 40 and the luminance distribution is created in the entire backlight 42 as in other embodiments described later. . When the luminance of the backlight 42 is set, the arithmetic unit 45 sends a drive signal to each of the current amount control elements 44 (R), 44 (G), and 44 (B) for each light source block 40 so that the luminance is obtained. To do.

  Note that the arithmetic unit 45 preferably monitors the amount of current applied to each light source block 40 and feeds back a control signal to the power supply unit 43 so that a stable current is always supplied to each light source block 40.

  The operation of the liquid crystal display device 10 configured as described above will be described. FIG. 5 is a flowchart showing the operation.

  For example, when the arithmetic unit inputs an external signal (step 501), the brightness of the backlight 42 corresponding to the external signal is set (step 502).

  When the luminance of the backlight 42 is set, the calculation unit 45 supplies the current applied to the LED elements 31 (R), 31 (G), and 31 (B) so as to obtain the set luminance of the backlight 42. A value is calculated (step 503). Here, the case where the brightness | luminance of the whole backlight 42 is made uniform as mentioned above is demonstrated. For example, when changing from the first luminance to the second luminance higher than the first luminance, the calculation unit 45 increases the current values of the LED elements 31 (R), 31 (G), and 31 (B). Set to. On the other hand, when trying to change from the first luminance to the third luminance lower than that, the calculation unit 45 reduces the current value of each LED element 31 (R), 31 (G), and 31 (B). Set to. In general, the luminance of the LED element and the current value applied thereto have a linear relationship.

  For example, when the second luminance is set, the calculation unit 45 calculates a chromaticity change corresponding to a luminance change from the first luminance to the second luminance (step 504). The calculation unit 45 cancels the calculated chromaticity change, that is, a ratio of the current amounts of the LED elements 31 (R), 31 (G), and 31 (B) for compensating the chromaticity change (hereinafter, referred to as the chromaticity change). Current ratio) is calculated (step 505). The calculation unit 45 uses the LED element 31 (R), 31 (with the current value calculated in step 503 and the current ratio calculated in step 505 (the current ratio changed from the current ratio at the time of the first luminance). G) and 31 (B) are driven (step 506). In this case, the calculating part 45 drives each LED element 31-33 by controlling each electric current amount control element 44 (R), 44 (G), and 44 (B).

  More specifically, the current values of the red, green, and blue LED elements 31 (R), 31 (G), and 31 (B) are increased so that the first luminance is changed to the second luminance. In this way, when the current value is calculated, when the LED element 31 (G) emits light at the current value, the light is shifted to the shorter wavelength side, that is, shifted to the blue side to emit light. In this case, the current value of the blue LED element 31 (B) is set to be lowered, and the blue color is controlled to be weakened against green or red. For example, the current ratio of red: green: blue = 2: 3: 1 at the first luminance is set to a current ratio of 2.5: 3.5: 1, for example. Note that this is only a simple example for easy understanding of the explanation, and various current ratios are conceivable.

  By compensating for the change in chromaticity in this way, even when the backlight 42 is driven at the second luminance or the third luminance, the vicinity of white of the image displayed on the liquid crystal display device 11 at the first luminance is obtained. Chromaticity is maintained. Since the color most sensitive to human vision is near white, there is no problem if the change in chromaticity near white is suppressed. Moreover, in this Embodiment, since the brightness | luminance of a backlight is controlled by controlling the electric current amount added to each LED element 31 (R), 31 (G), and 31 (B), power consumption is reduced. be able to.

  Note that the current values of the LED elements 31 (R), 31 (G), and 31 (B) at a certain luminance are not the same and are often different.

  Regarding the operations in steps 503 to 505, for example, the calculation unit 45 associates the luminance change data with the current ratio change data for compensating for the chromaticity change corresponding to the luminance change. The backlight 42 may be driven based on the converted table. This conversion table may be stored in advance in the memory (see FIG. 1) 16.

  FIG. 6 is a flowchart showing an operation according to another embodiment of the present invention. The display device that performs the operation of FIG. 6 may be the liquid crystal display device 10 shown in FIG.

  In steps 601 to 604 in the present embodiment, the same operations as in steps 501 to 504 are performed. In step 604, when the chromaticity change corresponding to the luminance change from the first luminance to the second luminance is calculated by the arithmetic unit 45, the liquid crystal panel control circuit 14 (see FIG. 1) calculates the chromaticity change. In order to compensate, a voltage ratio (hereinafter referred to as drive signal ratio) of drive signals applied to the sources corresponding to the red (R), green (G), and blue (B) pixels of the liquid crystal panel 13 is calculated (step). 605). Each of the red (R), green (G), and blue (B) pixels here is a so-called sub-pixel, but in general, one pixel is constituted by these three sub-pixels. The liquid crystal panel control circuit 14 sends a control signal to the source driver 17 so as to drive at the calculated drive signal ratio (step 606).

  Also by the processing shown in FIG. 6, the liquid crystal panel control circuit 14 associates the luminance change amount data with the drive signal ratio change amount data for compensating for the chromaticity change corresponding to the luminance change. The backlight 42 may be driven based on the conversion table. This conversion table may be stored in advance in the memory (see FIG. 1) 16.

  Thus, the change in chromaticity can be suppressed by changing the drive signal ratio of the liquid crystal of the backlight 42. Further, in the case of the present embodiment, it is possible to compensate for all color changes other than the vicinity of white as described above. However, when compensating for the change in chromaticity, the narrowest chromaticity range within the range of change in the drive signal ratio is the target of the chromaticity change to be compensated.

  Moreover, since the example shown in FIG. 6 is not a form in which the ratio of the LED elements 31 (R), 31 (G) and 31 (B) of the backlight 42 is changed as shown in FIG. A white LED may be used as the constituent LED element.

  Next, a mode in which the luminance partially changes in the display screen displayed on the liquid crystal display device 11 by individually controlling the luminance of each light source block of the backlight 42 will be described. Hereinafter, such driving of the backlight is referred to as “partial driving”.

  FIG. 7 shows another embodiment of the backlight. In the liquid crystal display device mounted with the backlight 12, the configuration other than the backlight 12 is the same as the configuration shown in FIG. In the following description, the description of the same members and functions of the liquid crystal display device 10 according to the embodiment shown in FIG. 1 will be simplified or omitted, and different points will be mainly described.

  The backlight 12 includes the above-described light source block, for example, nine light source blocks 1, 2,. The light source blocks 1, 2,..., 9 are arranged immediately behind the nine areas A 1 to A 9 of the display screen of the liquid crystal panel 13.

  Here, in order to simplify the description, as an example of the backlight 12, the light source blocks 1 to 9 are illustrated as being divided and arranged only in the vertical direction. Actually, as shown in FIG. 1, it is preferable to use a light source block that is divided and arranged in both the vertical direction and the horizontal direction. Alternatively, the light source block may be one in which the light source is divided and arranged only in the horizontal direction. FIG. 7 shows an example in which the display screen area is divided into nine. However, the display screen area may be less or more than nine, but it is preferable that the display screen area is as large as possible.

  Moreover, each area | region A1-A9 of a display screen is not set as an area | region where the light radiate | emitted only from the light source blocks 1-9 located right behind reaches | attains. Therefore, the light emitted from each of the light source blocks 1 to 9 reaches a region other than the region located immediately before by the scattering plate or the like, as will be described later.

  FIG. 8 is a block diagram showing the configuration of the liquid crystal display device according to the present embodiment, and particularly shows the configuration of the control unit 20 and the memory 16 (see FIG. 1). The control unit 20 of the liquid crystal display device 100 includes a video signal detection circuit 19, a light emission luminance distribution setting unit 21, a liquid crystal panel control circuit 14, and a backlight lighting control circuit 15. The memory 16 includes a light emission luminance distribution data storage unit 35 and a display luminance contribution rate data storage unit 37.

  The video signal detection circuit 19 includes a luminance signal detection circuit 25 that detects a luminance signal in the video signal, and a color signal detection circuit 26 that detects a color signal. In the embodiment according to the present invention, the luminance signal detected by the luminance signal detection circuit 25 is particularly handled.

  The light emission luminance distribution setting unit 21 sets the light emission luminance distribution of each of the light source blocks 1 to 9 according to the luminance signal detected by the luminance signal detection circuit 25. The light emission luminance distribution data storage unit 35 stores the light emission luminance distribution of the set light source blocks 1 to 9. In many cases, the emission luminance distribution data storage unit 35 mainly functions as a temporary buffer.

  The display luminance contribution rate data storage unit 37 stores display luminance contribution rate data that the light source blocks 1 to 9 affect the areas A1 to A9.

  The memory 16 is preferably a semiconductor memory or a dielectric memory, but is not limited thereto, and may be a memory using other magnetism or light.

  When a video signal is input to the video signal detection circuit 19, the liquid crystal panel control circuit 14 generates a display drive signal for performing display drive on the liquid crystal panel 13 based on the input video signal.

  The generated display drive signal is sent to the source driver 17 and the gate driver 18 of the liquid crystal panel 13 and input to each pixel of the liquid crystal panel 13 via the source driver 17 and the gate driver 18. The display drive signal is input in one field period or one frame period in synchronization with the field period or frame period of the input video signal. When a display drive signal is input to each pixel of the liquid crystal panel 13, a correction process described later is performed. In the case of the interlace method, one field consists of two frames, and in the case of the progressive method, one field consists of one frame. Hereinafter, “one field or one frame” is simply referred to as “one field”.

  The backlight lighting control circuit 15 individually controls driving of the light source blocks 1 to 9 according to the light emission luminance distribution set by the light emission luminance distribution setting unit 21.

  FIG. 9 is a diagram illustrating an example of the light emission luminance of each of the light source blocks 1 to 9. In FIG. 9, the horizontal axis indicates the position in the vertical direction of the display screen, the vertical axis indicates the light emission luminance, and is an example in which each of the light source blocks 1 to 9 emits light with substantially the maximum uniform luminance. The brightness is shown. Specifically, the value on the vertical axis is a value when the total light emission luminance of each of the regions A1 to A9 is normalized to 1 when each of the light source blocks 1 to 9 emits light at substantially maximum luminance. . In the case of the example shown in FIG. 9, the maximum value of the light emission luminance by one light source block among the light source blocks 1 to 9 is about 0.44 to 0.45, but it is needless to say that the value is not limited to this value.

  In the liquid crystal display device 100, a partition or the like for preventing the light emitted from each of the light source blocks 1 to 9 from reaching an area other than the area located immediately before each of the light source blocks 1 to 9 is provided. Not provided. Therefore, the light emitted from each of the light source blocks 1 to 9 reaches another area other than the area located immediately before, and contributes to the display luminance in the other area.

  FIG. 10 shows the luminance contribution ratio of each light source block to each position on the display screen when the emitted light is incident on the liquid crystal panel 13 when each light source block having the light emission luminance shown in FIG. 9 is used. It is a thing. The horizontal axis represents the position in the vertical direction of the display screen, and the vertical axis represents the luminance contribution ratio to the display luminance of the light emitted from each light source block 1-9.

  As shown in FIG. 10, the luminance contribution ratio of the light emitted from each of the light source blocks 1 to 9 is highest in the corresponding regions A1 to A9 of the light source blocks 1 to 9, respectively, and gradually increases as the distance from the regions A1 to A9 increases. To drop. In other words, taking only the area A1 as an example, the luminance contribution ratio by the light source block 1 is highest in the area A1 corresponding thereto. Taking only the area A2 as an example, the luminance contribution ratio by the light source block 2 is high in the area A2 corresponding thereto. Further, in the vicinity of the boundary between the areas A1 and A2, the luminance contribution ratios of the light source blocks 1 and 2 intersect, and the combined luminance contribution ratio appears to be high. For the light source blocks 1 and 9 arranged at both ends in the vertical direction, the luminance contribution ratio in the corresponding regions A1 and A9 is about 40%, and for the light source blocks 2 to 8 arranged in the middle position, The luminance contribution ratios in the areas A2 to A8 corresponding to the respective areas are about 20 to 30%. The reason why the luminance contribution ratios in the areas A1 and A9 are high is due to the structure of the liquid crystal panel 13 due to the relationship between the reflecting plate and the scattering plate.

  Thus, in the liquid crystal display device 100, the light emitted from each of the light source blocks 1-9 reaches an area other than the area corresponding to the light source blocks 1-9. That is, each light emitted from each of the light source blocks 1 to 9 is not irradiated to only the corresponding areas A1 to A9 separately, but is irradiated to other areas.

  In the liquid crystal display device 100, it is measured in advance how much the light emission luminance of each of the light source blocks 1 to 9 contributes to the display luminance of the regions A1 to A9, and this measured value is a simultaneous equation described later. The data for calculation is stored in the display luminance contribution rate data storage unit 37. The display luminance contribution rate data need not be stored as data in the display luminance contribution rate data storage unit 37 in advance, and can be derived by calculation in some form of function. Therefore, the display luminance contribution rate data storage unit 37 may not be provided, or the display luminance contribution rate data storage unit 37 may function as a temporary buffer.

  Next, a processing example of control related to screen display will be described with reference to the flowchart of FIG. This control is executed by the liquid crystal panel control circuit 14 and the backlight lighting control circuit 15 of the control unit 20 and is performed every time a video signal of one field is input to the liquid crystal panel control circuit 14.

  When a one-field video signal is input to the liquid crystal panel control circuit 14 (step 1101), the luminance signal detection circuit 25 detects the display luminance distribution of one video (original video) generated by the input video signal. (Step 1102). Therefore, the display brightness of each area A1 to A9, for example, the average display brightness obtained by averaging the display brightness of each part for each area A1 to A9 is detected.

  The light emission luminance distribution setting unit 21 sets the light emission luminance distribution of each of the light source blocks 1 to 9 constituting the backlight 12 based on the detected display luminance distribution (step 1103). When setting the light emission luminance distribution, the luminance contribution ratio of the light emission luminances of the light source blocks 1 to 9 with respect to the display luminances of the regions A1 to A9 is considered. Specifically, each light source is expressed by simultaneous equations (2) to (10) using the display luminance contribution rate data (see FIG. 10) stored in advance in the display luminance contribution rate data storage unit 37 of the memory 16. The light emission brightness of blocks 1 to 9 is set.

  Next, the calculation unit 45 sets the current value applied to each LED element 31 (R), 31 (G), and 31 (B) to each light source block 1 so as to obtain the set luminance distribution of the backlight 42. ˜9 are calculated individually (step 1104). For example, in the case where any one or a plurality of blocks among the light source blocks 1 to 9 are to be changed from the first luminance to the second luminance higher than the first luminance, the calculation unit 45 selects the light source block. Is set to increase the current value of each LED element 31 (R), 31 (G), and 31 (B). Hereinafter, among the light source blocks 1 to 9, a target light source block whose luminance is changed is referred to as a “target light source block”. When changing from the first luminance to the third luminance lower than the first luminance, the calculation unit 45 determines the current values of the LED elements 31 (R), 31 (G), and 31 (B) included in the target light source block. Set to lower.

  For example, when the second luminance is set, the calculation unit 45 calculates a chromaticity change corresponding to a luminance change from the first luminance to the second luminance (step 1105). The computing unit 45 calculates the current ratio of each LED element 31 (R), 31 (G), and 31 (B) to compensate for the calculated chromaticity change (step 1106). The computing unit 45 drives the LED elements 31 (R), 31 (G), and 31 (B) of the target light source block with the current value calculated in step 1104 and the current ratio calculated in step 1106 ( Step 1108), which will be described later, can compensate for the chromaticity change near white.

  By compensating for the change in chromaticity in this way, even when the backlight 42 is driven at the second luminance or the third luminance, the vicinity of white of the image displayed on the liquid crystal display device 11 at the first luminance is obtained. Chromaticity is maintained. In the present embodiment, the amount of current applied to each LED element 31 (R), 31 (G), and 31 (B) is controlled, and since partial driving is performed, the luminance of the backlight is controlled. Therefore, power consumption can be reduced.

  Next, after setting the light emission luminance of each of the light source blocks 1 to 9 as in step 1103, the liquid crystal panel control circuit 14 displays the display luminance of the pixels corresponding to the areas A 1 to A 9 of the display screen of the liquid crystal panel 13. A drive signal for the liquid crystal panel 13 is generated so as to be optimized (step 1107). That is, a drive signal for the liquid crystal panel 13 is generated according to the light emission luminance distribution set in step 1103. More specifically, the drive signal is generated based on the amount of deviation between the set light emission luminance of each of the light source blocks 1 to 9 and the optimum value of the display luminance in each part of the display screen. The optimum value is the display luminance required in each part of the display screen when the original video is displayed based on the input video signal. Accordingly, a deviation amount correction value for correcting the deviation amount is required in each part of the display screen when light is emitted from each of the light source blocks 1 to 9 with the light emission luminance set as described above. It is a value for calculating the transmissivity of the liquid crystal required in each pixel in order to obtain a display luminance of the same. To put it simply, for example, when the light emission luminance of a certain region of each of the regions A1 to A9 is ½ of the constant luminance as in the conventional case, the light of the liquid crystal pixel corresponding to that region. Correction is performed so that the transmittance is doubled.

  And the control part 20 sends out the light emission drive signal according to the light emission luminance distribution set in step 1103 from the backlight lighting control circuit 15 to each light source block 1-9, and sets each said light source block 1-9. The light is emitted with the emission luminance distribution. In this case, as described above, the calculation unit 45 controls each current amount control element 44 (R), 44 (G), and 44 (B) to obtain the current based on the current ratio calculated in step 1106 as the target. It adds to each LED element 31 (R), 31 (G), and 31 (B) of a light source block. Further, in synchronization with the partial drive of the backlight 12, the control unit 20 sends the drive signal of the liquid crystal panel 13 generated in step 1107 from the liquid crystal panel control circuit 14 to each pixel of the liquid crystal panel 13, and The video is displayed on the display screen (step 1108). When a display drive signal is sent from the liquid crystal panel control circuit 14 to each pixel of the liquid crystal panel 13, the transmittance of each pixel is varied according to the display drive signal for each field and emitted from the light source blocks 1 to 9. The transmission state of each light for each pixel is controlled.

  Therefore, the video is displayed in each part of the display screen in a state where the display luminance corresponding to the input video signal is obtained.

  Hereinafter, a specific method of control performed in steps 1101 to 1103 and steps 1107 to 1108 will be described.

  If the number of light source blocks of the backlight 12 is N (N is an integer of 2 or more), N = 9 in this example.

  In the liquid crystal display device 100, as described above, the display screen is divided into nine regions A1 to A9 as shown in FIG. 7, with the number corresponding to the number of light source block divisions N (= 9). Has been.

  For each of the regions A1 to A9, the maximum display luminance Ln_max (n = 1 to 9) determined by the input video signal is obtained. The maximum display brightness Ln_max is a value that provides the maximum display brightness in each part of the areas A1 to A9. The maximum display luminance is a value corresponding to the video signal for each field, and is different for each field.

  Here, the display brightness of all white (when the white peak is set for both the liquid crystal panel 13 and the backlight 12 (usually when the transmittance of the liquid crystal panel 13 is 100% and the output of the backlight 12 is 100%)) is L_peak. A ratio αn (n = 1 to 6) of the maximum display luminance Ln_max with respect to the display luminance L_peak of all white is obtained for the regions A1 to A9. Here, Ln_max ≦ L_peak.

αn = (Ln_max / L_peak) (1)
The ratio αn is a recovery limit indicating how much the light emission luminance of the light source blocks 1 to 9 corresponding to the regions A1 to A9 can be suppressed. That is, the display brightness of the liquid crystal panel 13 is roughly determined by “the transmittance of the liquid crystal panel (including the polarizing plate) × the light emission brightness of the backlight”. The recovery limit is that the light emission brightness of the backlight 12 is further reduced. Even if the transmittance of the liquid crystal panel is set to 100%, the maximum display luminance Ln_max cannot be obtained. The recovery limit αn corresponds to the luminance signal of the video signal. In step 1102, the recovery limit αn is obtained.

  In the above, the value of the recovery limit αn is obtained based on the maximum display luminance Ln_max of each of the areas A1 to A9. However, depending on the video content, αn ′ = based on the average display luminance Ln_ave of each of the areas A1 to A9. It is also possible to perform luminance control by obtaining the value of the recovery limit αn ′ by (Ln_ave / L_peak). When the control is performed by obtaining the value of the recovery limit αn ′, it is difficult to reproduce a complete original image, but it is possible to reproduce the original image in a range that is less affected by appearance.

  As described above, the light emission luminances of the other light source blocks 1 to 9 contribute to the display luminances of the respective regions A1 to A9 in addition to the light emission luminances of the light source blocks 1 to 9 corresponding to the regions A1 to A9. Therefore, the light source blocks 1 to 9 that do not correspond to the regions A1 to A9 can be controlled only by controlling the emission luminance of the light source blocks 1 to 9 corresponding to the regions A1 to A9 according to the recovery limits αn of the regions A1 to A9. It is not possible to perform control in consideration of light emission luminance.

  Accordingly, the light emission rate βn (n = 1 to 9) for each of the light source blocks 1 to 9 is obtained in consideration of the light emission luminance of the light source blocks 1 to 9 that do not correspond to the regions A1 to A9. The light emission rate βn is a value indicating the ratio of the actual light emission luminance of each light source block 1 to the maximum light emission luminance (when white peak is set) of each light source block 1 to 9, and in the range of 0 ≦ βn ≦ 1. Desired.

The light emission rate βn is calculated using the luminance contribution ratios K _{X, Y} (see FIG. 10) of the light source blocks 1 to 9 for the regions A1 to A9. As described above, the luminance contribution rate data of the light source blocks 1 to 9 shown in FIG. 10 is stored in the display luminance contribution rate data storage unit 37 in advance, and the stored light source block when the light emission rate βn is calculated. Data of luminance contribution ratios 1 to 9 is read out.

In the luminance contribution rate Kx, y, X indicates the regions A1 to A9, and Y indicates the light source blocks 1-9. For example, K _1,1 indicates the luminance contribution ratio of the light source block 1 positioned at the top with respect to the area A1, and for example, K _2,3 indicates the luminance contribution ratio of the light source block 3 positioned at the third position from the top with respect to the area A2. Indicates. As shown in FIG. 10, the luminance contribution rate is not constant in each region for each of the light source blocks 1 to 9, but the display luminance contribution rate data storage unit 37 has, for example, the luminance contribution rate Kx, y as The data at the center of each of the areas A1 to A9 is stored.

  The luminous rate βn is obtained by solving the multiple simultaneous equations (inequality) (2) to (10) shown in FIG.

  In step 1103, the light emission rate βn (0 ≦ βn ≦ 1) is calculated using the multiple simultaneous equations, and the light emission luminance of each of the light source blocks 1 to 9 is set so as to satisfy the light emission rate βn. A luminance distribution is set.

  The multiple simultaneous equations described above can be used regardless of the configuration of the backlight because the number of n only changes according to the number of divisions of the backlight.

  Moreover, although the example which calculates | requires (beta) n for every light source block 1-9 was shown above, for example, for every primary color of red, green, blue, or every luminescent color of the backlight 12, (beta) n is calculated separately, and brightness | luminance It is also possible to perform control.

  FIG. 13 shows a state in which when a video signal for one field is input, the light emission rate βn is calculated using the above method, and the light emission luminance of each of the light source blocks 1 to 9 of the backlight 12 is controlled. It is an example.

  In FIG. 13, the horizontal axis indicates the position of the display screen in the vertical direction. In FIG. 13, the data of each point connected by a broken line indicates the recovery limit αn in each of the regions A1 to A9, and the data of each point connected by a solid line indicates the light emission rate βn of the light source blocks 1 to 9 in each of the regions A1 to A9. Indicates the total value. That is, the graph of FIG. 13 is a graph representing the simultaneous equations. Thus, the light emission rate βn is set to a value close to the recovery limit αn, and the light emission luminance of the light source blocks 1 to 9 is efficiently controlled. In this example, the display brightness of the area A5 is the lowest, the display brightness increases as the distance from the area A5 increases, and the display brightness is the highest in the area A1.

  In this way, by using the recovery limit αn and the luminance contribution rate Kx, y, by solving the multiple simultaneous equations, the light emission rate βn of the light source blocks 1 to 9 is obtained and the light emission luminance of each of the light source blocks 1 to 9 is controlled, The light emission luminance of each of the light source blocks 1 to 9 can be suppressed according to the display state of the video. Thereby, the power consumption of the backlight 12 can be reduced. For example, for black parts in the video, the light source block corresponding to the area is turned off, and for bright parts in the video, the light source block corresponding to the area is turned on to display a high contrast video. It becomes possible to do.

  Further, in the present embodiment, since display luminance contribution ratio data indicating how the luminance of one light source block affects the entire display screen is stored, the original image can be faithfully reproduced, High definition image quality can be obtained.

  In the operation shown in FIG. 11, an example is shown in which the current ratio of each LED element 31 (R), 31 (G), and 31 (B) of the target light source block is changed. However, as shown in FIG. 6, in the partial drive of the backlight 12, a drive signal ratio applied to the pixels of the liquid crystal display device 11 in the region corresponding to the target light source block among the regions A1 to A9 is calculated. The liquid crystal display device 11 may be driven with the calculated drive signal ratio.

  Further, as described above, the display screen of the liquid crystal display device 11 of FIG. 7 shows an example in which the regions A1 to A9 are divided in the vertical direction to make the description easy to understand. However, as shown in FIG. 1, the light source block 40 may be arranged in a matrix on the display screen and the partial driving may be performed, and then the chromaticity change compensation operation may be performed.

  As described above, after the light emission rate βn is set and the light emission luminance distribution by each of the light source blocks 1 to 9 is set, as shown below, the display luminance of each part of the display screen of the liquid crystal panel 13 is set to the video display. A shift amount correction value for each pixel to obtain an optimum value at the time is calculated. This is the process of step 1107 described above. This step 1107 may be performed before step 1104 described above.

  The deviation amount correction value is calculated based on data on display luminance characteristics of the liquid crystal panel 13 shown in FIG. In FIG. 14, the horizontal axis indicates the set gradation (voltage) S_data of the liquid crystal panel 13 when the output of the backlight 12 is 100% (when fully lit), and the vertical axis indicates the liquid crystal panel 13 with respect to the set gradation S_data. Display luminance L_data is shown. Data of the display luminance characteristic f shown in FIG. 14 is obtained in advance and stored in the memory 16, for example.

  For each pixel, γ is the ratio between the display brightness L_peak of all white and the set display brightness L_set. The set display brightness L_set refers to the display brightness when the pixel has a transmittance of 100% when light is emitted from the light source blocks 1 to 9 for which the light emission brightness is set based on the light emission ratio βn.

γ = L_peak / L_set (11)
As described above, the set gradation S_data of the video (original video) displayed when the video signal is input is determined based on the display luminance L_data by the data shown in FIG.

L_data = f (S_data) (12)
The corrected set gradation S_data ′ with respect to the set display brightness L_set is calculated by the following expression based on the ratio γ between the display brightness L_peak of all white and the set display brightness L_set and the set gradation S_data. The correction setting gradation S_data ′ is a shift amount correction value for calculating the transmittance required for each pixel.

S_data ′ = f (γ × L_data) ⁻¹ (13)
By setting the transmissivity of each pixel so that the corrected set gradation S_data ′ is obtained, the original image is reproduced with the optimum display luminance.

  FIG. 15 is a block diagram showing a configuration of a backlight lighting control circuit according to still another embodiment of the liquid crystal display device. In this embodiment, an embodiment in which the backlight 42 is partially driven will be described.

  The backlight lighting control circuit 115 has a configuration in which a PWM signal generator 56 is further added to the backlight lighting control circuit 15 shown in FIG. The PWM signal generator 56 is provided for each light source block 40 and outputs a PWM signal to each of the current amount control elements 44 (R), 44 (G), and 44 (B) according to the control of the arithmetic unit 45. . That is, the PWM signal generator 56 individually performs PWM driving for each light source block 40.

  FIG. 16 is a diagram showing a configuration of the calculation unit 55 of the backlight lighting control circuit 115. As shown in FIG. The calculation unit 55 includes a switching control unit 49 that switches between the luminance control of the backlight 42 by PWM driving by the PWM signal generation unit 56 and the luminance control of the backlight 42 by current driving described above. The switching control unit 49 is provided for each light source block 40.

  The switching control unit 49 includes the current ratio calculation unit 51, the light emission luminance setting unit 53, the luminance threshold setting unit 54, the comparator 57, and the switch 52.

  The current ratio calculation unit 51 processes the operations in steps 503 to 505 described in the embodiment in FIG.

  The light emission luminance setting unit 53 sets the light emission luminance of the corresponding light source block 40. Specifically, the light emission luminance distribution setting unit 21 sets the light emission luminance distribution of the entire backlight 42 as described in the partial drive shown in FIGS.

  The brightness threshold value setting unit 54 sets a predetermined threshold value of the light emission brightness of the corresponding light source block. The luminance threshold setting unit 54 does not necessarily have to be provided for each light source block 40. In practice, one luminance threshold setting unit common to one backlight 42 is often provided.

  The comparator 57 compares the light emission luminance set by the luminance threshold value setting unit 54 with the threshold value, and switches the switch 52 according to the output of High and Low. Thereby, the backlight lighting control circuit 115 performs, for example, PWM driving and current driving on the boundary whether or not the luminance signal of the input video signal becomes a predetermined threshold in a certain area of the display screen. Can be controlled.

  FIG. 17 is a flowchart showing the operation of the liquid crystal display device including the backlight lighting control circuit 115.

  Steps 1701 to 1703 are the same as steps 1101 to 1103 shown in FIG. In step 1704, the light emission luminance distribution (light emission luminance for each light source block 40) set in step 1703 and the luminance threshold value set by the luminance threshold value setting unit 54 are compared by the comparator 57.

  As a result of the comparison in step 1704, for example, if the emission luminance is lower than the threshold value (NO in step 1705), the switching control unit 49 generates a PWM signal from the PWM signal generation unit 56, thereby causing the luminance of the backlight by PWM driving. Are controlled (step 1706). Since this step 1706 is PWM driving, the emission wavelengths of the LED elements 31 (R), 31 (G) and 31 (B) do not change. Accordingly, the chromaticity change compensation operation is not performed. Further, in the PWM driving of step 1706, a driving signal for the liquid crystal panel is generated (step 1706-1) as in steps 1104 and 1105, and the driving signal is sent to the backlight and the liquid crystal panel, respectively (step 1706). -2).

  As a result of the comparison in step 1704, for example, when the emission luminance is higher than the threshold (YES in step 1705), in steps 1707 to 1711, the switching control unit 49 switches to current driving, and the calculation unit 55 performs chromaticity by this current driving. A process for compensating for the change is performed. Steps 1707 to 1711 correspond to steps 1104 to 1108 shown in FIG.

  The threshold set by the brightness threshold setting unit 54 can be set as appropriate. For example, the luminance can be controlled by PWM driving up to the normal 100% emission luminance, and can be switched to current driving when the emission luminance exceeds 100%. That is, when the value of the recovery limit αn = (Ln_max / L_peak) in the above formula (1) exceeds 1, the luminance can be controlled by current driving. Thereby, since it can switch to a current drive only when comparatively big electric power is required, power consumption can be reduced.

  However, the threshold value is not limited to when the value of the recovery limit αn = (Ln_max / L_peak) in the above formula (1) is 1, and may be 0.8 or 0.9. Alternatively, the threshold value may be set in a range of 0.7 to 0.9.

  In particular, as shown in FIG. 18, the present embodiment is effective for processing a “white push-up” image in which a high-luminance portion is included in the central portion of the original image, for example. FIG. 18 schematically shows the operation in the case of YES in step 1705 shown in FIG. FIG. 18 shows an example of an image in which lightning occurs in the night sky.

  In the embodiment shown in FIGS. 15 and 16, the case where the backlight 42 is partially driven has been described. However, this embodiment is a case of driving to obtain uniform luminance over the entire display screen that is not partially driven (FIGS. The embodiment shown in FIG. In that case, the switching control unit 49 may not be provided for each light source block, and only needs to be provided for the entire backlight 42.

  The present invention is not limited to the embodiment described above, and various modifications are possible.

  In each of the above embodiments, the chromaticity change compensation operation by controlling the current ratio as shown in FIG. 5 (or FIGS. 11 and 17), and the driving of the liquid crystal display device 11 as shown in FIG. A mode in which any one of the chromaticity change compensation operations by the signal ratio control is performed is shown. However, both of these operations may be performed. For example, compensation for chromaticity changes near white can be performed by controlling the current ratio, and compensation for chromaticity changes other than near white can be performed by controlling the drive signal ratio.

It is a schematic diagram which shows the display apparatus which concerns on one embodiment of this invention. It is a figure which shows an example of the single cell in which each LED element of RGB which comprises a backlight is arranged. It is a figure which shows the equivalent circuit of FIG. It is a figure which shows the structure of a backlight lighting control circuit and a backlight. It is a flowchart which shows operation | movement of a liquid crystal display device. It is a flowchart which shows the operation | movement which concerns on other embodiment of this invention. It is a figure which shows the structure of the backlight which concerns on other embodiment. It is a block diagram which shows the structure of a control part and memory. It is the figure which showed the example of the light-emitting luminance distribution of each light source block. FIG. 10 shows the luminance contribution ratio of each light source block to each position on the display screen when the emitted light is incident on the liquid crystal panel when each light source block having the light emission luminance shown in FIG. 9 is used. It is a flowchart which shows operation | movement of the liquid crystal display device carrying the backlight shown in FIG. An example of a multiple simultaneous equation for setting the emission luminance distribution will be shown. This is an example showing a state in which when a video signal for one field is input, the light emission rate βn is calculated using the above method, and the light emission luminance of each light source block of the backlight is controlled. It is a graph which shows the display-luminance characteristic with respect to the setting gradation of a liquid crystal panel. It is a block diagram which shows the structure of the backlight lighting control circuit which concerns on another embodiment of a liquid crystal display device. It is a figure which shows the structure of the calculating part of this backlight lighting control circuit shown in FIG. It is a flowchart which shows operation | movement of the liquid crystal display device containing the backlight lighting control circuit shown in FIG. It is a figure which shows the operation | movement of a partial drive typically.

Explanation of symbols

A1 to A9: Display screen area 1 to 9, 40 ... Light source block 10, 100 ... Liquid crystal display device 11 ... Liquid crystal display device 12, 42 ... Backlight 13 ... Liquid crystal panel 14 ... Liquid crystal panel control circuit 15, 115 ... Backlight Lighting control circuit 16 ... Memory 19 ... Video signal detection circuit 20 ... Control unit 21 ... Luminance distribution setting unit 25 ... Luminance signal detection circuit 26 ... Color signal detection circuit 31 (R), 31 (G), 31 (B) ... LED element 35... Emission luminance distribution data storage unit 37... Display luminance contribution rate data storage unit 44 (R), 44 (G), 44 (B)... Current amount control element 45, 55. ... Current ratio calculator 56 ... PWM signal generator

Claims (11)

A backlight having an LED element;
Brightness setting means for setting the brightness of the backlight;
Current driving means for driving the backlight by controlling the amount of current applied to the LED element so as to obtain the set brightness;
Compensating means for compensating for a change in chromaticity according to a change in the amount of current by the current driving means. A display control apparatus comprising: The display control device according to claim 1,
The backlight has LED elements of three primary colors,
The display control apparatus according to claim 1, wherein the compensation means includes current ratio control means for controlling a ratio of current amounts applied to the LED elements by the current driving means. The display control device according to claim 2,
The backlight is
A backlight having a plurality of pixels respectively corresponding to the three primary colors and irradiating the light to a display device that changes the light transmittance for each pixel,
The display control apparatus, wherein the compensation means includes drive signal ratio control means for controlling a ratio of magnitudes of drive signals applied to the pixels corresponding to the three primary colors. The display control device according to claim 1,
The backlight is
A backlight having a plurality of pixels respectively corresponding to the three primary colors and irradiating the light to a display device that changes the light transmittance for each pixel,
The display control apparatus, wherein the compensation means controls a ratio of magnitudes of drive signals applied to the pixels corresponding to the three primary colors. The display control device according to claim 1,
PWM driving means for driving the backlight by a PWM method so as to obtain the set luminance;
The display control apparatus further comprising: switching means for switching between brightness control of the backlight by the current driving means and brightness control of the backlight by the PWM driving means. The display control device according to claim 5,
The switching means is driven by the PWM drive means when the brightness set by the brightness setting means is less than or equal to a predetermined value, and when the set brightness exceeds the predetermined value, the current drive means A display control device that is driven. A display control device for a display device that displays a video corresponding to an input video signal on a display screen by changing light transmittance for each of a plurality of pixels,
A backlight having an LED element that emits the light, and a plurality of light source blocks that are arranged corresponding to a plurality of regions that are configured by the LED element and into which the display screen is divided;
Storage means for storing data of a contribution ratio of display luminance with respect to each area of the display screen when each light source block emits light;
Detecting means for detecting display brightness of the display screen by the video signal;
Luminance distribution setting means for setting a light emission luminance distribution of each light source block according to the detected display luminance using the stored contribution rate data;
Current driving means for driving the backlight by controlling the amount of current applied to the LED element so as to obtain the set luminance distribution;
Compensating means for compensating for a change in chromaticity according to a change in the amount of current by the current driving means. A display control apparatus comprising: A display device having a plurality of pixels and displaying an image by changing light transmittance for each pixel;
A backlight having an LED element emitting the light;
Brightness setting means for setting the brightness of the backlight;
Current driving means for driving the backlight by controlling the amount of current applied to the LED element so as to obtain the set brightness;
Compensating means for compensating for a change in chromaticity in accordance with a change in the amount of current by the current driving means. A display having a plurality of pixels and a display screen constituted by each of the pixels, and displaying an image corresponding to an input video signal on the display screen by changing a light transmittance for each pixel. The device,
A backlight having an LED element that emits the light, and a plurality of light source blocks that are arranged corresponding to a plurality of regions that are configured by the LED element and into which the display screen is divided;
Storage means for storing data of a contribution ratio of display luminance with respect to each area of the display screen when each light source block emits light;
Detecting means for detecting display brightness of the display screen by the video signal;
Luminance distribution setting means for setting a light emission luminance distribution of each light source block according to the detected display luminance using the stored contribution rate data;
Current driving means for driving the backlight by controlling the amount of current applied to the LED element so as to obtain the set luminance distribution;
Compensating means for compensating for a change in chromaticity in accordance with a change in the amount of current by the current driving means. Setting the brightness of a backlight having LED elements;
Driving the backlight by controlling the amount of current applied to the LED element to obtain the set brightness;
Compensating a change in chromaticity according to a change in the amount of current. A display control method comprising: A display having a plurality of pixels and a display screen constituted by each of the pixels, and displaying an image corresponding to an input video signal on the display screen by changing a light transmittance for each pixel. Display of display device comprising device and backlight having LED element that emits light and a plurality of light source blocks that are configured by the LED element and are arranged corresponding to a plurality of areas into which the display screen is divided A control method,
Storing display luminance data for each area of the display screen when each light source block emits light; and
Detecting display brightness of the display screen by the video signal;
Using the stored contribution rate data, setting a light emission luminance distribution of each light source block according to the detected display luminance;
Driving the backlight by controlling the amount of current applied to the LED elements to obtain the set luminance distribution;
Compensating a change in chromaticity according to a change in the amount of current. A display control method comprising: