JP6671850B2 - Display device and control method thereof - Google Patents

Description

  The present invention relates to a display device and a control method thereof.

Conventionally, in a transmissive liquid crystal display device including a single liquid crystal, there is a problem in that contrast is reduced due to leakage of backlight light.
As one method of improving the contrast, there is a technique of forming a double structure in which a liquid crystal (hereinafter, referred to as a secondary liquid crystal) is further interposed between a conventional liquid crystal (hereinafter, referred to as a primary liquid crystal) and a backlight. Was. As a result, the number of gradations equal to the product of the two display gradation numbers can be expressed, so that the contrast can be improved (Patent Document 1).
As another method of improving the contrast, there is a technique of dividing a screen into a plurality of backlight control areas and controlling the luminance of the backlight and the transmittance of the liquid crystal based on the feature amount of the image data. Thus, by controlling the backlight light for each area, it is possible to suppress the floating of black and improve the contrast (Patent Document 2).
The reason for controlling the transmittance of the liquid crystal will be described below. When the lighting state of the backlight is controlled for each area, a luminance distribution of the backlight occurs. In a display device that is required to faithfully reproduce the luminance of an image, the output luminance is affected by the luminance distribution of the backlight, and the luminance distribution of the backlight affects the luminance reproducibility of the image. For this reason, it was necessary to smooth the luminance distribution. In Patent Document 2, in view of this, the brightness distribution smoothing process is controlled in consideration of the transmittance of the liquid crystal.

  Furthermore, when there is unevenness in the liquid crystal panel as well as in the above-described backlight luminance distribution, there is a problem that the display quality deteriorates because the uniformity of the output luminance is impaired. In general, the unevenness of a liquid crystal panel often occurs due to the thickness of liquid crystal molecules and the like, and the characteristics of the unevenness differ from one liquid crystal panel to another. As one of the unevenness correction processes of a liquid crystal panel in a display device including one liquid crystal panel and a backlight, there is a method of performing a correction process in accordance with a pixel having the lowest output luminance. However, in a display device having a structure in which a plurality of liquid crystal panels are superimposed, if unevenness correction processing is performed independently for each liquid crystal panel, the output luminance after passing through the liquid crystal panels is reduced by the number of the superposed liquid crystal panels. In a display device that is required to faithfully reproduce the luminance of an image, it is necessary to correct a decrease in luminance by increasing a backlight control value. Therefore, in a display device in which a plurality of liquid crystal panels are superimposed, as one method for maintaining the uniformity of the output luminance, there is a technique of disposing a black and white panel other than the outermost surface and correcting luminance unevenness with respect to the black and white panel. (Patent Document 3).

JP-A-5-88197 JP-A-2002-99250 JP 2008-122536 A

  However, in Patent Literature 3, since the backlight is lit in all areas, high contrast cannot be achieved by controlling the area of the backlight. The present invention has been made in view of the above circumstances, and in a display device having a dual structure of a liquid crystal panel and area control of a backlight, it is possible to improve unevenness of the liquid crystal panel and to achieve high performance by controlling the area of the backlight. It is an object of the present invention to provide a technique for achieving both contrast enhancement.

The present invention
A first panel capable of controlling light transmittance;
A second panel provided on the back side of the first panel and capable of controlling light transmittance;
A light-emitting means provided on the back side of the second panel and comprising a plurality of control areas capable of independently controlling luminance;
Setting means for setting a control value of each control area based on a feature amount in each divided area of image data corresponding to each control area,
First control means for controlling the transmittance of the first panel based on the image data;
Second control means for controlling the transmittance of the second panel based on the control value of each control area;
With
The light emitting means controls light emission of each of the control areas based on a set control value,
The second control means, for each control area, the brightness distribution from the light emitting means irradiating light irradiated to the second panel based-out out calculated the the control value of the control area, the irradiation light is the A first smoothing gain for smoothing a luminance distribution of light irradiated on the first panel by transmitting the light through the second panel is calculated based on the luminance distribution of the irradiated light, and the first smoothing gain is calculated as the first smoothing gain. A display device, wherein the transmittance of the second panel is controlled based on the control signal.

The present invention
A first panel capable of controlling light transmittance;
A second panel provided on the back side of the first panel and capable of controlling light transmittance;
A light-emitting means provided on the back side of the second panel and comprising a plurality of control areas capable of independently controlling luminance;
A control method of a display device comprising:
A setting step of setting a control value of each control area based on a feature amount in each divided area of image data corresponding to each control area,
A first control step of controlling the transmittance of the first panel based on the image data;
A second control step of controlling a transmittance of the second panel based on a control value of each control area;
Has,
The light emitting means controls light emission of each of the control areas based on a set control value,
In the second control step, said each control area, the brightness distribution from the light emitting means irradiating light irradiated to the second panel based-out out calculated the the control value of the control area, the irradiation light is the A first smoothing gain for smoothing a luminance distribution of light irradiated on the first panel by transmitting the light through the second panel is calculated based on the luminance distribution of the irradiated light, and the first smoothing gain is calculated as the first smoothing gain. And controlling the transmittance of the second panel based on the control signal.

  ADVANTAGE OF THE INVENTION According to this invention, in the display apparatus comprised by the dual structure of the liquid crystal panel and the area control of a backlight, the improvement of the unevenness of a liquid crystal panel and the high contrast by the area control of a backlight can be compatible.

Functional block diagram of the display device according to the first embodiment FIG. 2 is a diagram illustrating a configuration of a display device according to the first embodiment. FIG. 9 is a diagram illustrating image data, a divided area, and a maximum pixel value distribution according to the first and second embodiments. FIG. 9 is a diagram illustrating a pixel value distribution of input image data in a line segment AB according to the first and second embodiments. FIG. 5 is a flowchart for illustrating a backlight control value calculation method according to the first embodiment. FIG. 7 is a diagram illustrating a backlight control value, a luminance distribution, and a smoothing gain according to the first embodiment. 5 is a flowchart for illustrating a method of calculating a backlight luminance smoothing gain according to the first embodiment. FIG. 5 is a flowchart showing a backlight control value adjusting method according to the first embodiment. FIG. 7 is a diagram for describing a method for obtaining output luminance of a display device in the first embodiment. FIG. 10 is a diagram illustrating output luminance and a combined unevenness correction gain of the line segment AB according to the first embodiment. FIG. 10 is a diagram illustrating a secondary liquid crystal aperture ratio of the line segment AB of Example 1 and a luminance distribution after transmission of the secondary liquid crystal. FIG. 8 is a diagram for explaining the luminance distribution and effect of the output image of the line segment AB according to the first embodiment. Functional block diagram of a display device according to a second embodiment FIG. 10 is a diagram for explaining the secondary liquid crystal aperture ratio and the effect of the line segment AB in the second embodiment.

(Example 1)
FIG. 1 is a block diagram illustrating the functions of the display device according to the first embodiment, and FIG. 2 illustrates the configuration of the display device.
The display device 1 in FIG. 1 includes a feature amount acquisition unit 101, a control value calculation unit 102, a luminance distribution calculation unit 103, a smoothing processing unit 104, a combined unevenness correction gain storage unit 105, a secondary liquid crystal aperture ratio determination unit 106, It comprises a light unit 107, a secondary liquid crystal unit 108, and a primary liquid crystal unit 109.

In the configuration of FIG. 1, the feature amount obtaining unit 101 obtains input image data, divides the input image data into a plurality of divided areas, and obtains a feature amount of an image in each divided area. In the first embodiment, the feature amount acquiring unit 101 acquires the maximum pixel value of the image in the divided area (hereinafter, the maximum pixel value) as the feature amount. The maximum pixel value is transmitted to the control value calculation unit 102.
The control value calculation unit 102 acquires the feature amount (here, the maximum pixel value) of each divided area from the feature amount acquisition unit 101, and calculates the backlight control value of the control area corresponding to each divided area based on the feature amount. . The control value calculation unit 102 transmits the calculated backlight control value to the luminance distribution calculation unit 103 and the backlight unit 107.

The luminance distribution calculation unit 103 acquires a backlight control value for each control area from the control value calculation unit 102, and calculates a luminance distribution of the entire backlight. The luminance distribution calculation unit 103 transmits information on the calculated luminance distribution to the smoothing processing unit 104.
The smoothing processing unit 104 acquires the luminance distribution information from the luminance distribution calculation unit 103, and calculates a smoothing gain (first smoothing gain) for canceling and smoothing the luminance distribution based on the luminance distribution information. . The calculated smoothing gain information is transmitted to the secondary liquid crystal aperture ratio determining unit 106.

  The combined unevenness correction gain storage unit 105 holds the combined unevenness correction gain obtained by combining the unevenness correction gains of the primary liquid crystal and the secondary liquid crystal, and transmits the combined unevenness correction gain to the secondary liquid crystal aperture ratio determining unit 106. The synthetic unevenness correction gain is calculated based on the transmittance of light when light incident on the secondary liquid crystal (second panel) passes through the secondary liquid crystal and the primary liquid crystal (first panel) and exits from the primary liquid crystal. (Variation information). In the first embodiment, it is assumed that the combined unevenness correction gain is obtained by measurement in advance and stored in the combined unevenness correction gain storage unit 105. Further, the combined unevenness correction gain storage unit 105 increases the backlight control value when the minimum value of the luminance distribution of the transmitted light of the secondary liquid crystal is smaller than the reference luminance when measuring the combined unevenness correction gain. Information on the used adjustment gain is also stored. The information on the adjustment gain is output to the control value calculation unit 102, and the control value calculation unit 102 multiplies the adjustment gain calculated based on the feature amount of the image by the adjustment gain to obtain a final backlight control value. Details of the synthesis unevenness correction gain and the adjustment gain will be described later.

The secondary liquid crystal aperture ratio determination unit 106 acquires the smoothing gain information of the smoothing processing unit 104 and the composite unevenness correction gain of the composite unevenness correction gain storage unit 105, and determines the aperture ratio (transmittance) of the secondary liquid crystal unit 108. decide. The secondary liquid crystal aperture ratio information is transmitted to the secondary liquid crystal unit 108.
The backlight unit 107 is a light emitting unit that is provided on the back side of the secondary liquid crystal unit 108 and includes a plurality of control areas that can independently control the luminance. The backlight unit 107 acquires the backlight control value calculated for each control area by the control value calculation unit 102, and turns on the light source of each control area with the backlight control value.

The secondary liquid crystal unit 108 is a second panel (secondary liquid crystal) provided on the back side of the primary liquid crystal unit 109 and capable of controlling the light transmittance. The aperture ratio (transmittance) of each pixel of the secondary liquid crystal unit 108 is controlled based on the aperture ratio of each pixel determined by the secondary liquid crystal aperture ratio determination unit 106.
The primary liquid crystal unit 109 is a functional block including a first panel (primary liquid crystal) capable of controlling light transmittance, and first control means for controlling the transmittance of the first panel based on image data. . The aperture ratio (transmittance) of the primary liquid crystal unit 109 is controlled for each pixel based on the input image data.
In the configuration of the display device according to the first embodiment, as shown in FIG. 2, the primary liquid crystal unit 109 is used as a display surface, and the secondary liquid crystal unit 108 is disposed on the back of the primary liquid crystal unit 109. The backlight unit 107 is disposed.

Hereinafter, the processing contents of the display device according to the first embodiment will be described using the monochrome 8-bit input image data illustrated in FIG. 3A as an example. In the first embodiment, it is assumed that the backlight unit includes two monochrome liquid crystals having the same pixel size and a white backlight. Further, when the pixel value of the input image data is 255, control is performed so that the luminance of the output image becomes the reference luminance. Here, the reference luminance is 200 cd / m ² . The reference luminance is referred to as an output setting luminance value and is represented by LSet. Gamma is assumed to be 1.0. Further, the contrast ratio between the primary liquid crystal and the secondary liquid crystal is assumed to be 100: 1.

  In the first embodiment, as shown in FIG. 3B, the control area of the backlight is divided into 3 areas in the vertical direction and 4 areas in the horizontal direction, and the feature amount acquisition area is also divided into similar areas. Shall be. FIG. 3C shows the relationship between the input image data and the feature amount acquisition area at this time. In the following description, one-dimensional data obtained by cutting the input image data along the line segment AB in FIG. This will be explained. FIG. 4 shows a one-dimensional pixel value distribution when cutting is performed between the line segments AB in FIG. 3C, and FIG. 3D shows an output result for each area by the feature amount acquisition unit 101.

  An example of a method of calculating a backlight control value according to the first embodiment will be described. In the first embodiment, two types of backlight control values are determined depending on whether or not the maximum pixel value is zero for each area. Since the backlight control value and the output setting luminance value have a correlation, in the first embodiment, the backlight control value is set in two stages of 0 or 200 for convenience. Hereinafter, the procedure of the backlight control value calculation method will be described with reference to the flowchart shown in FIG. In step S801, it is determined whether the maximum pixel value of the attention area is zero. If the maximum pixel value is zero, the backlight control value is set to zero in step S802; otherwise, it is set to 200 in step S803. After the above steps, the backlight control value for each area is obtained as FIG.

  An example of a method for calculating a backlight luminance distribution in the first embodiment will be described. In the first embodiment, as shown in FIG. 3B, the backlight light source is located at the center of the area, and the backlight luminance distribution for each area that emits light according to the backlight control value follows a Gaussian distribution. Further, the backlight luminance distribution over the entire screen can be expressed by adding (overlapping) the backlight luminance distribution for each area in accordance with the principle of light superposition. At this time, the backlight luminance distribution for each area generated by the line segment AB and the backlight luminance distribution for all areas have distributions indicated by 1001 and 1002 in FIG. 6B, respectively. If the backlight luminance distribution in the area becomes smooth, it will not depend on the luminance distribution of the backlight, so that the luminance reproducibility in the area can be maintained. A luminance distribution that can maintain luminance reproducibility in the area (hereinafter, referred to as a backlight smoothed luminance distribution) is a luminance distribution indicated by 1003 in FIG. The backlight smoothed luminance distribution is determined based on the backlight control values shown in FIG. One of the reasons that the peak luminance of the backlight for each area allows the output setting luminance value to be exceeded is that when the backlight luminance distribution of all areas is calculated, the lack of luminance at the edge of the area is considered. This is to prevent it. Another reason is to prevent a decrease in luminance value due to a decrease in output luminance after the correction of combining unevenness described later.

  First, the purpose of the backlight luminance distribution smoothing process in the first embodiment will be described. In the backlight luminance distribution smoothing processing, a gain is calculated for converting the backlight luminance distribution of all areas shown by 1002 in FIG. 6B into the backlight smoothed luminance distribution shown by 1003 in FIG. That is the purpose. Hereinafter, the above-mentioned gain is referred to as a backlight luminance smoothing gain.

Next, a processing procedure until a backlight luminance smoothing gain is calculated will be described in detail with reference to a flowchart shown in FIG. In addition, since a mathematical expression is used in the calculation method, the pixel position of the secondary liquid crystal is defined as Y here.
In step S1101, the smoothing processing unit 104 acquires the backlight luminance distribution of all areas calculated by the luminance distribution calculation unit 103 as LReal (Y). As described above, the obtained backlight luminance distribution of all areas is 1002 in FIG. 6B by adding the backlight luminance distribution of each area.
Next, in step S1102, the smoothing processing unit 104 acquires the backlight smoothed luminance distribution as LFlat (Y). Here, as described above, since the backlight control value and the output setting luminance value have a correlation, the backlight smoothing luminance distribution is set at 200 cd / m ² over the entire area and is set to 1003 / m ² in FIG. Becomes

Finally, in step S1103, the smoothing processing unit 104 calculates the backlight luminance smoothing gain from the backlight luminance distribution of all areas and the backlight smoothed luminance distribution. Assuming that the backlight luminance smoothing gain is BlGain (Y), the backlight luminance smoothing gain can be calculated by Expression 101.

BlGain (Y) = LFFlat (Y) / LReal (Y) Equation 101

The distribution of the gain calculated by Expression 101 is shown by reference numeral 1201 in FIG.
Based on the above processing procedure, the backlight smoothed luminance distribution becomes 1003 in FIG.

  The processing procedure of the method of calculating the combined unevenness correction gain held by the combined unevenness correction gain storage unit 105 according to the first embodiment will be described in detail with reference to a flowchart illustrated in FIG. The calculation of the combined unevenness correction gain described here is performed at the time of assembling the display device 1 or at the time of shipment from the factory, and the calculation result is stored in the combined unevenness correction gain storage unit 105 before the display device 1 is shipped. You. However, the method by which the display device 1 acquires the combined unevenness correction gain is not limited to this. A configuration may be adopted in which the display device 1 acquires the combined unevenness correction gain by supplying information on the combined unevenness correction gain from the outside to the display device 1 in use. In this case, for example, a portable storage medium such as a USB memory or a CD-ROM can be connected to the display device 1 to read out information on the combined unevenness correction gain stored in the portable storage medium. Also, the external device storing the information on the combined unevenness correction gain and the display device 1 are connected by wire such as a USB cable or a LAN cable, or by wireless such as infrared rays, Bluetooth (registered trademark), or wireless LAN, and combined from the external device. The unevenness correction gain can also be obtained.

  FIG. 9 shows a configuration example for calculating the unevenness correction gain. As shown in FIG. 9, a display device 1401, a two-dimensional luminance distribution measuring device 1402, and an unevenness correction gain calculating device 1403 are provided. Here, the two-dimensional luminance distribution measuring device 1402 and the unevenness correction gain calculation device 1403 are described as external devices to the display device 1401, but the display device 1401 may have the function of the unevenness correction gain calculation device 1403. In this case, the configuration of the display device 1 in FIG. 1 further includes a block having the function of the unevenness correction gain calculation device 1403. Information on the combined unevenness correction gain output from the functional block corresponding to the unevenness correction gain calculation device 1403 is stored and held in the combined unevenness correction gain storage unit 105. In the configuration in which the function of the unevenness correction gain calculating device 1403 is included in the display device, even when the unevenness of the primary liquid crystal or the secondary liquid crystal has changed over time in the display device in use, the latest unevenness state is reflected. Display control can be performed using the combined unevenness correction gain. Therefore, display with less unevenness can be performed over a long period of time.

In the flowchart of FIG. 8, first, in step S1301, the unevenness correction gain calculation device 1403 acquires a luminance distribution output from the display device 1401 (hereinafter, referred to as an output luminance distribution). The two-dimensional luminance distribution measuring device 1402 acquires the output luminance distribution in two dimensions.

  Here, the input image data at the time of obtaining the output luminance distribution and the setting of the aperture ratio of the secondary liquid crystal will be described in detail. In order to generate a highly accurate unevenness correction gain, it is necessary to maximize the variation width of the luminance variation. Therefore, when acquiring the output luminance distribution, predetermined image data (in this case, full-screen white Image data). On the other hand, it is necessary to set a backlight luminance smoothing gain as the aperture ratio of the secondary liquid crystal. This is because if the luminance distribution of the backlight is not smoothed, the luminance distribution of the backlight is superimposed on the combined unevenness correction gain, and a highly accurate unevenness correction gain cannot be generated. Since the output luminance distribution obtained by the above procedure is output with only the combined unevenness of the primary liquid crystal and the secondary liquid crystal superimposed, the variation in the brightness distribution is equal to the combined unevenness. Among the output luminance distributions of the display device obtained by the above procedure, the output luminance distribution between the line segments AB in FIG. 3C is shown as 1501 in FIG.

Next, in step S1302, the unevenness correction gain calculation device 1403 obtains the minimum luminance value in the output luminance distribution of the display device. Assuming that the minimum luminance value is LOutMin, LOutMin = 200 cd / m ² from FIG.
Next, in step S1303, the unevenness correction gain calculation device 1403 calculates a combined unevenness correction gain from the output luminance distribution and the minimum luminance value. Assuming that the combined unevenness correction gain is MrGain (Y), the combined unevenness correction gain can be calculated by Expression 102.

MrGain (Y) = LOutMin / LOut (Y) Equation 102

The distribution of the combined unevenness correction gain in Example 1 calculated by Expression 102 is shown by 1601 in FIG.
Next, in step S1304, the unevenness correction gain calculation device 1403 compares the minimum luminance value of the output luminance distribution with the output setting luminance value, terminates the processing if the values match, and proceeds to step 1305 if they do not match. move on. In the example of FIG. 10A, the minimum luminance value is 200, which matches the output setting luminance value, and thus the processing ends in step S1304. Here, an example has been described in which the unevenness correction gain calculation device 1403 calculates the combined unevenness correction gain MrGain (Y) and stores it in the combined unevenness correction gain storage unit 105. However, information on the output luminance distribution LOut (Y) and the minimum luminance value LOutMin may be stored in the combined unevenness correction gain storage unit 105. In this case, the display device 1 may calculate the combined unevenness correction gain MrGain (Y) based on the expression 102.

On the other hand, when the minimum luminance value does not match the output setting luminance value, when the backlight unit 107 is controlled with the backlight control value determined in the above-described step S <b> 803, excessive or insufficient luminance occurs, and luminance reproducibility is reduced. Not maintained. Therefore, in this case, in Step 1305, the unevenness correction gain calculation device 1403 calculates an adjustment gain for matching the minimum luminance value with the output setting adjustment gain. The details of the processing will be described below. The unevenness correction gain calculation device 1403 calculates an adjustment gain for reducing excess or deficiency of the backlight control value from LOutMin which is the minimum value of the output luminance distribution and LSet which is the output setting luminance value. If the adjustment gain at this time is AdGain, it can be calculated by Expression 103.

AdGain = LSet / LOutMin Equation 103

The calculated adjustment gain AdGain is stored in the combined unevenness correction gain storage unit 105 together with the combined unevenness correction gain. The adjustment gain AdGain is output to the control value calculator 102. When the adjustment gain AdGain is input from the combined unevenness correction gain storage unit 105, the control value calculation unit 102 multiplies the adjustment gain AdGain by 200 set in the above-described step S803 to obtain the final backlight control value. And By doing so, it is possible to reduce the excess and deficiency of the backlight luminance and maintain the luminance reproducibility.

The method for determining the aperture ratio of the secondary liquid crystal in the first embodiment will be described in detail. The secondary liquid crystal aperture ratio determination unit 106 determines the secondary liquid crystal aperture ratio by multiplying the combined unevenness correction gain and the backlight luminance smoothing gain. The distribution of the secondary liquid crystal aperture ratio in Example 1 is shown by 1701 in FIG. 1702 shows the distribution of the backlight luminance smoothing gain described above. Using the secondary liquid crystal aperture ratio calculated by the above procedure, the luminance distribution after passing the secondary liquid crystal has a minimum luminance value of 200 cd / m ² , which is the output setting luminance value, as indicated by 1801 in FIG. Is obtained. Here, the reason why the luminance value after the transmission of the secondary liquid crystal varies is because the luminance value for correcting the liquid crystal unevenness of the primary liquid crystal is superimposed on the output setting luminance value.

The effect of the first embodiment will be described. When the pixel value distribution between the line segments AB shown in FIG. 4 is input, the luminance distribution output from the display device is 1901 in FIG. 12 from (A), part of the pixel value 255 is obtained at 200 cd / ^{m 2,} portions of the pixel value 128 can be obtained by 100 cd / ^{m 2.} When the same processing is performed on the entire image data, the output image obtained when the image of FIG. 3A is input, as shown in FIG. Can be smoothed. Further, when the pixel values in the area are all zero, the backlight is turned off, so that the contrast in the screen can be improved.

  The above is the details of the first embodiment. With the above configuration, in the display device configured with the area control of the dual liquid crystal and the backlight, the luminance distribution of the backlight and the smoothing processing of the unevenness of the primary liquid crystal and the secondary liquid crystal are performed on the secondary liquid crystal side. , And the reproducibility of luminance can be maintained. Further, since only the aperture ratio on the secondary liquid crystal side is corrected, signal processing on the primary liquid crystal side becomes easy. In the first embodiment, the input image data is described as a monochrome image. However, the input image data may be configured with a double liquid crystal composed of a color liquid crystal and a color backlight corresponding to a color image. However, from the viewpoint of smoothing the luminance distribution of the backlight on the secondary liquid crystal side, it is preferable to use a monochrome liquid crystal for the secondary liquid crystal when using a white backlight, and to use a color liquid crystal when using an RGB color backlight. desirable. Further, in the first embodiment, the number of divisions of the backlight area is 4 × 3 = 12, but the number of divisions is not limited to this.

(Example 2)
In the first embodiment, the secondary liquid crystal aperture ratio is determined by multiplying the luminance distribution smoothing gain of the backlight by the liquid crystal unevenness smoothing gain, thereby maintaining the luminance reproducibility and reducing the liquid crystal unevenness. Embodiment 2 aims at realizing further higher contrast in addition to the above effects. In the first embodiment, the pixel portion where the input signal is black in the backlight lighting area is 2 cd / m ² as shown in FIG. 12A, and the luminance of the black pixel (hereinafter, referred to as “only”) is the contrast ratio of the primary liquid crystal. Black luminance) was determined. Therefore, the secondary liquid crystal aperture ratio determining unit in the second embodiment sets the aperture ratio corresponding to the pixel of the secondary liquid crystal to zero for the black pixel portion of the input image data.
FIG. 13 shows the configuration of the display device according to the second embodiment. The display device 1 of FIG. 13 has a configuration in which input image data is input to the secondary liquid crystal aperture ratio determination unit 106 in the display device 1 described in the first embodiment.

The effect of the second embodiment will be described. In the first embodiment, as shown in FIG. 11A, the aperture ratio of the secondary liquid crystal is calculated. In the second embodiment, the aperture ratio of the pixel at the position of the black image data of the input image data is set to the minimum value (here, To set to (zero), the aperture ratio of the secondary liquid crystal is as shown in FIG. By this processing, the black luminance of the output image can be calculated as 0.02 cd / m ² from the product of the contrast ratio of the secondary liquid crystal and the primary liquid crystal, so that it is possible to further reduce the black luminance.

(Other Examples)
The present invention supplies a program for realizing one or more functions of the above-described embodiments to a system or an apparatus via a network or a storage medium, and one or more processors in a computer of the system or the apparatus read and execute the program. This processing can be realized. Further, it can also be realized by a circuit (for example, an ASIC) that realizes one or more functions.

101: feature quantity acquisition unit, 102: control value calculation unit, 105: composite unevenness correction storage unit, 106: secondary liquid crystal aperture ratio determination unit, 107: backlight unit, 108: secondary liquid crystal unit, 109: primary liquid crystal Department

Claims (18)

A first panel capable of controlling light transmittance;
A second panel provided on the back side of the first panel and capable of controlling light transmittance;
A light-emitting means provided on the back side of the second panel and comprising a plurality of control areas capable of independently controlling luminance;
Setting means for setting a control value of each control area based on a feature amount in each divided area of image data corresponding to each control area,
First control means for controlling the transmittance of the first panel based on the image data;
Second control means for controlling the transmittance of the second panel based on the control value of each control area;
With
The light emitting means controls light emission of each of the control areas based on a set control value,
The second control means, for each control area, the brightness distribution from the light emitting means irradiating light irradiated to the second panel based-out out calculated the the control value of the control area, the irradiation light is the A first smoothing gain for smoothing a luminance distribution of light irradiated on the first panel by transmitting the light through the second panel is calculated based on the luminance distribution of the irradiated light, and the first smoothing gain is calculated as the first smoothing gain. A display device for controlling the transmittance of the second panel based on the control signal. Storage for storing non-uniformity information, which is information on variation in light transmittance of each pixel when light incident on the second panel passes through the second panel and the first panel and exits from the first panel. Further comprising means,
The display device according to claim 1, wherein the second control unit controls the transmittance of the second panel based on the unevenness information acquired from the storage unit. The second control means controls a transmittance of a region of the second panel corresponding to a black region, which is a region of a black pixel of the image data, to a predetermined transmittance, and controls a transmittance of another region of the second panel. The display device according to claim 1, wherein the transmittance is controlled to be higher than the predetermined transmittance. The non-uniformity information is obtained when the transmittance of the first panel is controlled based on predetermined image data and the transmittance of the second panel is controlled based on the first smoothing gain. 3. The display device according to claim 2, further comprising information obtained by measuring a luminance distribution of the transmitted light by an external measurement unit. 4. The display device according to claim 4, wherein the unevenness information includes information of a second smoothing gain, which is calculated based on the brightness distribution measured by the measuring unit, for canceling and smoothing the brightness distribution. The display device according to claim 5, wherein the second control means controls the transmittance of the second panel based on the first smoothing gain and the second smoothing gain. The unevenness information is information on an adjustment gain calculated based on the minimum luminance in the luminance distribution measured by the measuring unit and a reference luminance corresponding to a control value used for controlling the light emitting unit at the time of the measurement. The display device according to claim 5, comprising: The display device according to claim 7, wherein the setting unit sets a control value of each of the control areas based on the feature amount and the unevenness information. 9. The control unit according to claim 8, wherein the setting unit corrects a control value set based on the feature amount based on the adjustment gain such that a minimum luminance in a luminance distribution of transmitted light of the second panel becomes equal to the reference luminance. 10. Display device. 10. The apparatus according to claim 1, wherein the second control unit controls a transmittance of a region of the second panel corresponding to a black region that is a region of a black pixel of the image data to a minimum value. 11. Display device. A first panel capable of controlling light transmittance;
A second panel provided on the back side of the first panel and capable of controlling light transmittance;
A light-emitting means provided on the back side of the second panel and comprising a plurality of control areas capable of independently controlling luminance;
A control method of a display device comprising:
A setting step of setting a control value of each control area based on a feature amount in each divided area of image data corresponding to each control area,
A first control step of controlling the transmittance of the first panel based on the image data;
A second control step of controlling a transmittance of the second panel based on a control value of each control area;
Has,
The light emitting means controls light emission of each of the control areas based on a set control value,
In the second control step, said each control area, the brightness distribution from the light emitting means irradiating light irradiated to the second panel based-out out calculated the the control value of the control area, the irradiation light is the A first smoothing gain for smoothing a luminance distribution of light irradiated on the first panel by transmitting the light through the second panel is calculated based on the luminance distribution of the irradiated light, and the first smoothing gain is calculated as the first smoothing gain. Controlling the transmittance of the second panel based on the control method. The display device may be configured such that unevenness, which is information on variation in light transmittance of each pixel when light incident on the second panel passes through the second panel and the first panel and exits from the first panel. Further comprising storage means for storing information;
The method according to claim 11, wherein in the second control step, the transmittance of the second panel is controlled further based on the unevenness information acquired from the storage unit. In the second control step, the transmittance of the area of the second panel corresponding to the black area which is the area of the black pixel of the image data is controlled to a predetermined transmittance, and the transmittance of the other area of the second panel is controlled. The method according to claim 11, wherein the transmittance is controlled to be higher than the predetermined transmittance. The non-uniformity information is obtained when the transmittance of the first panel is controlled based on predetermined image data and the transmittance of the second panel is controlled based on the first smoothing gain. The control method for a display device according to claim 12, further comprising information obtained by measuring the luminance distribution of the transmitted light of the light source by an external measuring means. 15. The control of the display device according to claim 14, wherein the unevenness information includes information of a second smoothing gain calculated based on the brightness distribution measured by the measurement unit and for canceling and smoothing the brightness distribution. Method. The method according to claim 15, wherein in the second control step, the transmittance of the second panel is controlled based on the first smoothing gain and the second smoothing gain. The unevenness information is information on an adjustment gain calculated based on the minimum luminance in the luminance distribution measured by the measuring unit and a reference luminance corresponding to a control value used for controlling the light emitting unit at the time of the measurement. The control method for a display device according to claim 15, wherein the control method includes: 18. The method according to claim 11, wherein in the second control step, the transmittance of a region of the second panel corresponding to a black region which is a region of a black pixel of the image data is controlled to a minimum value. A method for controlling a display device.

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