Abstract:
Disclosed is a backlight device that suppresses the increase of maximum power consumption. A light-emitting unit ( 121 ) is provided with a plurality of light-emitting areas that individually emit illumination light. A power estimation unit ( 136 ) estimates the power consumption of the light-emitting unit ( 121 ). A duty lower-limit setting unit ( 137 ) varies the range in which drive conditions that include the duty and peak value of a drive pulse for causing each of the plurality of light-emitting areas to emit light can be set, in accordance with changes in the estimated power consumption. A drive condition specification unit specifies the drive conditions for each of the plurality of light-emitting areas within the varied range. An LED driver ( 123 ) drives each of the plurality of light-emitting areas under the specified drive conditions.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a backlight apparatus and a display apparatus using a backlight apparatus. 
       BACKGROUND ART 
       [0002]    A non-self-luminous display apparatus, typified by a liquid crystal display apparatus, has a backlight apparatus (or hereinafter simply referred to as “backlight”) in the back. A display apparatus of this kind displays an image through an optical modulation section, which adjusts the amount of light which is reflected or which transmits, in the light emitted from the backlight, in accordance with image signals. Also, a display apparatus of this kind turns on and off a light source intermittently in synchronization with scanning of images, in order to improve the movie blur with a display apparatus of a hold type drive. 
         [0003]    Generally, as examples of this intermittent lighting, there are a scheme of making an entire light emitting surface of a backlight flash with predetermined timing (which is generally referred to as “backlight blink”) and a scheme of dividing a light emitting surface of a backlight into a plurality of scan areas in vertical directions as shown in  FIG. 1  and making the individual scan areas flash sequentially in synchronization with scanning of images as shown in  FIG. 2  (which is generally referred to as “backlight scan”). 
         [0004]    For example, the liquid crystal display apparatus of the backlight blink scheme disclosed in patent literature 1 controls the drive duty (hereinafter also referred to as “duty”) and drive current (hereinafter also referred to as “peak value”) of a light source by determining whether an input image is a still image or a moving image. 
         [0005]    For example, the liquid crystal display apparatus of the backlight scan scheme disclosed in patent literature 2 controls the drive duty of a light source in accordance with the scale of motion in an image. 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         PTL 1 
         Japanese Patent Publication No. 3535799 
         PTL 2 
         Japanese Patent Application Laid-Open No. 2006-323300 
       
     
       SUMMARY OF INVENTION 
     Technical Problem 
       [0010]    With the liquid crystal display apparatus disclosed in above patent literature 2, even when an input image is a movie, if the image in part of an image display area corresponding to part of scan areas is not moving, the drive duty in that scan area is not lowered and is maintained. That is to say, it is possible to prevent movie blur and improve movie resolution by not lowering the drive duty in part of scan areas and by lowering the drive duty only in the other scan areas. 
         [0011]    In this case, in order to maintain the same brightness in all scan areas, it is necessary to increase the drive current in scan areas where the drive duty is lowered, compared to scan areas where the drive duty is not lowered. 
         [0012]    Now, if the kind of light source that does not lower the rate of light emission even when the drive current is increased is used as the backlight, controlling the light source to increase the drive current simply by the magnitude the drive duty is decreased, is sufficient. 
         [0013]    However, if a general light source to reduce that lowers the rate of light emission when the drive current increases (e.g. LED: Light Emitting Diode) is used, the control to increase the drive current to achieve predetermined brightness needs to be carried out to an extent to compensate for the lowering of light emission rate. In this case, the power consumption increases. 
         [0014]    Furthermore, when the scale of motion in an image is greater in a greater number of image display areas, a light source of a greater number of scan areas operates at low efficiency, and, as a result of this, increase in power consumption becomes distinct. 
         [0015]    Furthermore, regardless of the light emission characteristic of a light source, backlight power consumption increases when the light adjustment value of a light source, which is derived from an image signal, increases (in other words, when the brightness of a light source needs to be increased). Consequently, even when the light adjustment value of a large number of light sources power consumption increases distinctly. 
         [0016]    Thus, a backlight apparatus which controls both drive duty and drive current per divided area such as a scan area has a problem of increasing maximum power consumption and incurring increased costs of a power supply circuit and light source drive circuit. 
         [0017]    It is therefore an object of the present invention to provide a backlight apparatus and display apparatus that can reduce the increases of maximum power consumption. 
       Solution to Problem 
       [0018]    A backlight apparatus according to the present invention has: a light emitting section that has a plurality of light emitting areas to emit light individually; a power estimation section that estimates power consumption of the light emitting section; a drive condition changing section that changes a range that can be designated with respect to drive conditions including duties and peak values of drive pulses for allowing the plurality of light emitting areas to emit light, in accordance with change of estimated power consumption; a drive condition designating section that designates the drive conditions of the plurality of light emitting areas in changing ranges; and a drive section that drives the plurality of light emitting areas individually based on the designated drive conditions. 
         [0019]    A display apparatus according to the present invention has: the above backlight apparatus; and a light modulation section that displays an image by modulating an illuminating light from the plurality of light emitting areas in accordance with an image signal. 
       Advantageous Effects of Invention 
       [0020]    With the present invention, it is possible to reduce the increase of the maximum power consumption of a backlight apparatus. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0021]      FIG. 1  shows an example of a conventional scan area; 
           [0022]      FIG. 2  shows a conventional backlight scanning method; 
           [0023]      FIG. 3  is a block diagram showing a configuration of a liquid crystal display apparatus according to embodiment 1 of the present invention; 
           [0024]      FIG. 4  shows an image display areas on a liquid crystal panel according to embodiment 1 of the present invention; 
           [0025]      FIG. 5  shows light emitting areas and scan areas in a display section according to embodiment 1 of the present invention; 
           [0026]      FIG. 6  is a block diagram showing a configuration of an LED driver according to embodiment 1 of the present invention; 
           [0027]      FIG. 7  shows a macroblock segmented from the image display area according to embodiment 1 of the present invention; 
           [0028]      FIG. 8  is a block diagram showing a configuration for a motion amount detection section according to embodiment 1 of the present invention; 
           [0029]      FIG. 9A  shows a first example of a drive duty calculation method based on the amount of motion, according to embodiment 1 of the present invention; 
           [0030]      FIG. 9B  shows a second example of a drive duty calculation method based on the amount of motion, according to embodiment 1 of the present invention; 
           [0031]      FIG. 9C  shows a third example of a drive duty calculation method based on the amount of motion, according to embodiment 1 of the present invention; 
           [0032]      FIG. 10  shows a relationship between drive duty and drive current according to embodiment 1 of the present invention; 
           [0033]      FIG. 11A  shows examples of ON/OFF signal waveforms controlled by a scan controller according to embodiment 1 of the present invention; 
           [0034]      FIG. 11B  shows the duties of the ON/OFF signals shown in  FIG. 11A ; 
           [0035]      FIG. 12A  shows other examples of ON/OFF signal waveforms controlled by a scan controller according to embodiment 1 of the present invention; 
           [0036]      FIG. 12B  shows the duties of the ON/OFF signals shown in  FIG. 12A ; 
           [0037]      FIG. 13  shows a method of setting a lower-limit duty value based on power consumption, according to embodiment 1 of the present invention; 
           [0038]      FIG. 14  shows an operation of motion amount detection per image display area according to embodiment 1 of the present invention; 
           [0039]      FIG. 15  shows drive pulses per light emitting area, in the event the lower-limit duty value is set on a variable basis, according to embodiment 1 of the present invention; 
           [0040]      FIG. 16  shows drive pulses per light emitting area, in the event the lower-limit duty value is not set on a variable basis, according to embodiment 1 of the present invention; 
           [0041]      FIG. 17  is a block diagram showing a configuration of a liquid crystal display apparatus according to embodiment 2 of the present invention; 
           [0042]      FIG. 18  is a block diagram showing a configuration of a liquid crystal apparatus according to embodiment 3 of the present invention; 
           [0043]      FIG. 19  is a block diagram showing a configuration of a liquid crystal display apparatus according to embodiment 4 of the present invention; 
           [0044]      FIG. 20  is a block diagram showing a configuration of a liquid crystal display apparatus according to embodiment 5 of the present invention; 
           [0045]      FIG. 21  is a block diagram showing a configuration of a liquid crystal display apparatus according to embodiment 6 of the present invention; 
           [0046]      FIG. 22  shows a method of setting the upper-limit current value based on power consumption, base on embodiment 6 of the present invention; 
           [0047]      FIG. 23  is a block diagram showing a configuration of a liquid crystal display apparatus according to embodiment 7 of the present invention; 
           [0048]      FIG. 24  shows a method of correcting the amount of motion, according to embodiment 7 of the present invention; 
           [0049]      FIG. 25  shows a block diagram showing a method of setting the upper-limit motion amount value based on power consumption, according to embodiment 7 of the present invention; 
           [0050]      FIG. 26  is a block diagram showing a configuration of a liquid crystal display apparatus according to embodiment 8 of the present invention; 
           [0051]      FIG. 27  shows a method of reducing the detected amount of motion, according to embodiment 8 of the present invention; and 
           [0052]      FIG. 28  shows a method of setting a motion amount reduction coefficient based on power consumption, according to embodiment 8 of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0053]    Now, embodiments of the present invention will be described below in detail. 
       Embodiment 1 
       [0054]    Embodiment 1 of the present invention will be described below. 
         [0055]    A case will be described here with the present embodiment where power to be consumed is estimated from the drive duty and peak value, and where, based on the estimation result, the lower-limit value of drive duty is set on a variable basis. 
         [0056]    &lt;1-1. Configuration of Liquid Crystal Display Apparatus&gt; 
         [0057]    The configuration of a liquid crystal display apparatus will be described first.  FIG. 3  is a block diagram showing a configuration of a liquid crystal display apparatus according to the present embodiment. Liquid crystal display apparatus  100  has liquid crystal panel section  110 , illuminating section  120  and drive control section  130 . Illuminating section  120  and drive control section  130 , combined, constitute a backlight apparatus. 
         [0058]    The configuration of each component will be described in detail. 
         [0059]    &lt;1-1-1. Liquid Crystal Panel Section&gt; 
         [0060]    Liquid crystal panel section  110  has liquid crystal panel  111 , source driver  112 , gate driver  113  and liquid crystal controller  114 . 
         [0061]    When an image signal is received as input in liquid crystal panel section  110 , a signal voltage is applied to each pixel on liquid crystal panel  111  as a display section, from source driver  112  and gate driver  113 , with timing controlled by liquid crystal controller  114 . Consequently, liquid crystal panel  111  is able to modulate the illuminating light emitted from the back of liquid crystal panel  111  according to image signals, and, by this means, allows an image formed with a plurality of pixels to be displayed on a screen. That is to say, liquid crystal panel section  110  forms an optical modulation section. 
         [0062]    Now, in  FIG. 3 , the screen of liquid crystal panel  111  is divided by broken lines, and this expressly indicates that liquid crystal panel  111  has a plurality of image display areas, not that liquid crystal panel  111  is structurally divided or that these lines are actually displayed in an image. The same applies to the other drawings. 
         [0063]    With the present embodiment, as shown in  FIG. 4 , liquid crystal panel  111  has sixteen image display areas  11 - 44  obtained by dividing the whole screen in a matrix shape. 
         [0064]    Note that liquid crystal panel  111  is able to adopt an IPS (In-Plane Switching) scheme, VA (Vertical Alignment) scheme, and so on, but these are by no means limiting. 
         [0065]    &lt;1-1-2. Illuminating Section&gt; 
         [0066]    Illuminating section  120  emits illuminating light for displaying an image on liquid crystal panel  111  and emits illuminating light on liquid crystal panel  111  from the back side of liquid crystal panel  111 . 
         [0067]    Illuminating section  120  has light emitting section  121 . Light emitting section  121  adopts a direct-type configuration and is formed by placing a large number of point light sources on the back of a diffusion plate in a planar arrangement, so that light is emitted toward the diffusion plate. By this means, light emitting section  121  outputs, from its front surface side, light that is emitted from a light source and is incident from the back. 
         [0068]    The present embodiment uses LEDs  122  as point light sources. LEDs  122  all emit white light, and are configured to emit light at the same brightness if driven by the same drive conditions. Note that each LED  122  emits white light by itself or may be configured to emit white light by mixing RGB lights. 
         [0069]    Also note that elements other than LEDs may be used as point light sources, or elements that emit light other than white light may be used as well. 
         [0070]    Now, in  FIG. 1 , the light output surface of light emitting section  121  is divided by solid lines, and this expressly indicates that light emitting section  121  has a plurality of light emitting areas, not that light emitting section  121  is structurally divided. The same applies to other drawings as well. 
         [0071]    With the present embodiment, as shown in  FIG. 5 , light emitting section  121  has sixteen light emitting areas  11 - 44  obtained by dividing the whole screen in a matrix shape. Light emitting areas  11 - 14  are included in scan area  1 , light emitting areas  21 - 24  in scan area  2 , light emitting areas  31 - 34  in scan area  3 , and light emitting areas  41 - 44  in scan area  4 . 
         [0072]    Illuminating section  120  has LED driver  123  as a drive section to drive LEDs  122 . LED driver  123  has drive terminals which equal the light emitting areas in number, so as to drive each light emitting area individually. 
         [0073]      FIG. 6  shows an example of LED drivers  123 . LED driver  123  has: constant current circuit  141  that supplies current to a plurality of serially-connected LEDs  122 ; communication interface (I/F)  142  that receives current value data, which represents the peak value to report to constant current circuit  141 , from drive control section  130 , via a communication terminal; a digital-to-analog converter (DAC)  143  that converts current value data into a current command signal, which is an analog signal; and switch  144  that allows or blocks input of a current command signal from DAC  143  to constant current circuit  141 , according to ON/OFF signals provided from drive control section  130  via ON/OFF terminals. That is to say, LED driver  123  is configured such that a current proportional to the signal voltage of a current command signal is supplied from constant current circuit  141  to LED  122  when switch  144  is turned on and this current supply is blocked when switch  144  is turned off. This configuration is provided per light emitting area. 
         [0074]    Given the above configuration, LED driver  123  is able to make a plurality of scan areas be driven and emit light individually by the same drive conditions including the duties (i.e. ON duties) and peak values of drive pulses designated individually on a per scan area basis. 
         [0075]    &lt;1-1-3. Drive Control Section&gt; 
         [0076]    Drive control section  130  is an operation processing apparatus having motion amount detection section  131 , drive duty operation section  133 , drive current operation section  134 , scan controller  135 , power estimation section  136  and lower-limit duty value setting section  137 , and controls drive conditions including the duties and peak values of drive pulses on a per scan area basis based on an input image signal in each image display area. In drive control section  130 , motion amount correction section  132 , drive duty operation section  133 , drive current operation section  134  and scan controller  135 , combined, constitute a drive condition designating section which designate drive conditions on a per scan area basis. 
         [0077]    &lt;1-1-3-1. Motion Amount Detection Section&gt; 
         [0078]    Motion amount detection section  131 , as a motion detection section, detects the amount of motion in an image based on an input image signal. 
         [0079]    As for the method of detecting the amount of motion, there is, for example, a method of determining the amount of motion by performing pattern-matching of all macroblocks with the previous frame, in macroblock units. Here, macroblocks are individual areas that are defined by dividing image display areas smaller.  FIG. 8  shows macroblocks in image display area  2  of liquid crystal panel  111 . Note that, as a simpler method of motion detection, there is a method of using the scale of difference of an image signal from the previous frame in the same pixel position. 
         [0080]    With the present embodiment, motion amount detection section  131  is configured to output the maximum value of the amounts of motion of macro blocks determined by the former method. That is to say, if the maximum value of the amount of motion is the same between a case where an image over all individual image display areas and a case where an image moves only in part, the same value is output. 
         [0081]      FIG. 8  shows a configuration of motion amount detection section  131 . Motion amount detection sections  131  has: 1V delay section  151  that delays an input image signal by one frame, macroblock motion amount operation section  152  that operates the amount of motion in an image per macroblock with reference to the image signal of the previous frame, and maximum value calculation section  153  that calculates the maximum value in the amounts of motion operated. This configuration is provided per image display area. 
         [0082]    In the above configuration, motion amount detection section  131  detects the amount of motion of image per image display area. 
         [0083]    &lt;1-1-3-2. Drive Duty Operation Section&gt; 
         [0084]    Drive duty operation section  133  performs an operation for converting an amount of motion, which is detected in and output from motion amount detection section  131 , into a drive pulse duty value for each light emitting area. Drive duty operation section  133  determines the drive duty for each scan area, by applying a predetermined conversion formula to the amount of motion detected in each image display area, and determines the result as the drive duty to specify for each light emitting area. 
         [0085]      FIG. 9A ,  FIG. 9B  and  FIG. 9C  show the method of calculating drive duty based on the detected amount of motion, by graphs showing the relationships between the detected amount of motion and drive duty. 
         [0086]      FIG. 9A  shows an example case where the lower-limit value of duty is set at 50%. In this example, when an amount of motion of zero is detected, the drive duty calculated then is 100%, which is the upper-limit. Furthermore, when an amount of motion to match the maximum value M MAX  is detected, the drive duty calculated then is 50%, which is the lower-limit. Also, when an amount of motion between zero and the maximum value M MAX  is detected, the drive duty to be calculated becomes gradually lower as the detected amount of motion increases. For example, the drive duty is 95% when the detected amount of motion is 2.5, 67% when the detected amount of motion is 7.5, and 55% when the detected amount of motion is 10. 
         [0087]      FIG. 9B  shows an example case where the lower-limit value of duty that is set changed from 50% to 67%. In this example, when the detected amount of motion is zero, the drive duty to be calculated then is 100%, which is the upper-limit. Then, when the detected amount of motion is the predetermined maximum value M MAX , the drive duty to be calculated then is 67%, which is the lower-limit. Furthermore, until the detected amount of motion of 7.5, at which the drive duty of 67% is calculated, the drive duty to be calculated decreases gradually as the detected amount of motion increases, following the same changes as in the case of  FIG. 9A . Then, when an amount of motion to exceed the amount of motion of 7.5 is detected, the drive duty to be calculated then is fixed at 67%. 
         [0088]    Consequently, by providing a configuration for comparing the value obtained by a conversion formula and the lower-limit duty value that is set, and by making this structure to operate to select the lower-limit duty value when the lower-limit duty value is greater, it is possible to realize the calculation method shown in  FIG. 9B  using the conversion formula in the calculation method shown in  FIG. 9A  on an as is basis. 
         [0089]      FIG. 9C  shows another example case where the lower-limit duty value that is set changes from 50% to 67%. In this example, when the detected amount of motion is zero, the drive duty to be calculated then is 100%, which is the upper-limit. Then, when the detected amount of motion is the predetermined maximum value M MAX , the drive duty to be calculated then is 67%, which is the lower-limit. Furthermore, when an amount of motion between zero and the maximum value M MAX  is detected, the drive duty to be calculated then gradually decreases with smaller changes than shown in  FIG. 9A . 
         [0090]    Consequently, the calculation method shown in  FIG. 9C  cannot be realized by using the conversion formula of the calculation method shown in  FIG. 9A  as is. For example, process to calculate the coefficient in the equation from the increased lower-limit value of duty is required. 
         [0091]    Consequently, regarding the operation when the lower-limit value of duty changes, to compare the calculation methods shown in  FIGS. 9B and 9C , the calculation method shown in  FIG. 9C  requires an operation for deriving a new conversion formula. By contrast with this, the calculation method shown in  FIG. 9B  only requires processing for changing the threshold for comparison, and therefore is advantageous in terms of processing load. 
         [0092]    On the other hand, even when the lower-limit value of duty changes, with the calculation method shown in  FIG. 9B , drive duty changes in a light emitting area where the drive duty is originally large (that is, in a light emitting area where the amount of motion is small). By contrast with this, with the calculation method shown in  FIG. 9C , the drive duty changes in all light emitting areas. A described later, when the lower-limit value of duty is changed depending on power consumption, with the calculation method shown in  FIG. 9C , it is possible to control power in proportion to the lower-limit value of duty. Furthermore, with the calculation method shown in  FIG. 9B , cases might occur where drive duty changes only in part of the light emitting areas yet does not change in the surrounding light emitting areas. When drive conditions change locally like this, there is a likelihood of identifying unnecessary flicker between light emitting areas. With the calculation method shown in  FIG. 9C , drive conditions change in the whole light emitting area, so that it is possible to reduce the likelihood of identifying unnecessary flicker due to local change of drive conditions. 
         [0093]    The specific numerical values shown in  FIGS. 9A ,  9 B and  9 C are examples and may be changed variously. 
         [0094]    &lt;1-1-3-3. Drive Current Operation Section&gt; 
         [0095]    Drive current operation section  134  performs an operation for acquiring the peak value of a drive pulse from drive duty output from drive duty operation section  133 . That is to say, drive current operation section  134  determines the peak value in each light emitting area based on the drive duty calculated in each light emitting area. 
         [0096]    Now, drive current operation section  134  controls the peak values to achieve a predetermined level of brightness regardless of the variation of drive duty values. Consequently, as shown in  FIG. 10 , for example, drive current operation section  134  has a table showing the relationship between drive duty and peak value to make the brightness a predetermined value, and determines a peak value from drive duty with reference to this table. Note that the amount of motion and drive duty are substantially related such that drive duty decreases when the amount of motion increases, and the specific values in  FIG. 10  are given simply by way of example and various changes are possible. 
         [0097]    Drive current operation section  134  generates current value data, which is a digital signal to represent the determined peak value, and outputs this to illuminating section  120 . By this means, a peak value is designated as a drive condition per light emitting area. 
         [0098]    &lt;1-1-3-4. Scan Controller&gt; 
         [0099]    Based on the drive duties determined on a per scan area basis, scan controller  135  generates ON/OFF signals on a per scan area basis, at timing based on a vertical synchronization signal, and outputs the generated ON/OFF signals to illuminating section  120 . By this means, a drive duty is designated as a drive condition in every scan area. By this means, when an ON/OFF signal for one scan area is an ON signal, above LED driver  123  makes that scan area drive and emit light, or, if that ON/OFF signal is an OFF signal, instead of making that scan area drive and emit light, generates a drive pulse and supplies this drive pulse to LEDs  122  included in that scan area. 
         [0100]      FIG. 11A  shows examples of ON/OFF signal waveforms output from scan controller  135 . Here, ON/OFF signals that are output when, as shown in  FIG. 11B , the drive duties determined for four light emitting areas  11 ,  21 ,  31  and  41  are all 50% and identical. Image scan is performed in the order of image display area  11 , image display area  21 , image display area  31  and image display area  41 , and backlight scan is also performed in the order of light emitting area  11 , light emitting area  21 , light emitting area  31  and light emitting area  41 . 
         [0101]    Also, in the examples shown in  FIG. 11A , in the image scan period for image display areas  11 ,  21 ,  31  and  41 , the timing to turn off corresponding light emitting areas  11 ,  21 ,  31  and  41  is controlled, so that it is possible to improve movie resolution. 
         [0102]      FIG. 12A  shows other examples of ON/OFF signal waveforms output from scan controller  135 . Here, as shown in  FIG. 12B , ON/OFF signals that are output when the drive duties that are determined with respect to four light emitting areas  11 ,  21 ,  31  and  41  vary, are shown. As obvious from  FIG. 12A , when changing the drive duty of each light emitting area  11 ,  21 ,  31  or  41 , only the rising phase of the ON/OFF signal of each light emitting area  11 ,  21 ,  31  or  41  is changed, without changing the trailing phase. 
         [0103]    &lt;1-1-3-5. Power Estimation Section&gt; 
         [0104]    Power estimation section  136  performs an operation for estimating the power consumption of light emitting section  121  from the drive duty and peak value determined per light emitting area. 
         [0105]    Drive duty and peak value are both determined on a per light emitting area, so that power estimation section  136  estimates power consumption, individually, on a per light emitting area basis. Then, given that a common lower-limit value of duty is set in all light emitting areas, power estimation section  136  calculates the total power consumption of all light emitting areas—that is, the power consumption of light emitting section  121 —from the power consumptions estimated per light emitting area. 
         [0106]    To be more specific, power consumption Pij of light emitting area ij (i and j are both integers from 1 to 4 according to the present embodiment) can be estimated from following equation 1. Then, power consumption Pa of light emitting section  121  can be obtained by calculating the sum or average value of power consumptions estimated with respect to all light emitting areas. A MAX  in equation 1 is the maximum peak value that can be determined, Aij is the peak value determined with respect to light emitting area ij, and Dij is the drive duty determined with respect to light emitting area ij. 100% in equation 1 means that the maximum value of drive duty that can be determined is 100%. 
         [0000]    
       
         
           
             
               
                 
                   
                     ( 
                     
                       Equation 
                        
                       
                           
                       
                        
                       1 
                     
                     ) 
                   
                    
                   
                       
                   
                 
               
               
                 
                     
                 
               
             
             
               
                 
                   Pij 
                   = 
                   
                     
                       Aij 
                       × 
                       Dij 
                     
                     
                       
                         A 
                         MAX 
                       
                       × 
                       100 
                        
                       % 
                     
                   
                 
               
               
                 
                   [ 
                   1 
                   ] 
                 
               
             
           
         
       
     
         [0107]    Taking into account the linear relationship between the peak value and power if the power supply voltage is constant, and the linear relationship between drive duty and power if the drive pulse waveform is rectangular, it is possible to estimate the an indicator to show the magnitude of power consumption in each light emitting area in a simple manner using the above equation. 
         [0108]    Here, it is possible to use other methods of estimation, by, for example, estimating the power consumption in each light emitting area in watts, and calculating their total as estimated power consumption of light emitting section  121 . 
         [0109]    &lt;1-1-3-6. Lower-limit Duty Value Setting Section&gt; 
         [0110]    Lower-limit duty value setting section  137  performs an operation for setting the lower-limit duty value, which is the lower-limit value of duty, with respect to each light emitting area, by calculating this lower-limit duty value from the estimated power consumption (estimated power consumption) of light emitting section  121 . Lower-limit duty value setting section  137  constitutes a drive condition changing section that changes the range of drive conditions that can be designated. 
         [0111]      FIG. 13  shows the method of calculating the lower-limit value of duty based on estimated power consumption, by graphs representing the relationship between power and lower-limit duty value. In the example shown in  FIG. 13 , when estimated power consumption is the minimum value 0, the lower-limit duty value calculated then is 50%, which is the minimum value. The lower-limit value of duty to be calculated gradually decreases as estimated power consumption increases, and, when estimated power consumption is 1 m, which is the maximum value, the lower-limit value to be calculated then is 100%, which is the maximum value. For example, when estimated power consumption is 0.375, the lower-limit duty value to be calculated then is 67%. The numerical values shown in  FIG. 13  are only examples and can be changed variously. 
         [0112]    The lower-limit duty value, once set, is fed back to drive duty operation section  133 , and drive duty operation section  133  calculates drive duty based on this value. Then, drive current operation section  134  determines the peak value depending on the drive duty calculated in drive duty operation section  133 . 
         [0113]    Consequently, lower-limit duty value setting section  137  sets the lower-limit duty value at 50%, the minimum value of drive duty then calculated by drive duty operation section  133  is 50%. On the other hand, the maximum value of drive duty that can be calculated then by drive duty operation section  133  is 100%. Consequently in this case, the range of drive duty that can be determined in drive duty operation section  133  is 50-100% ( FIG. 9A ). With the present embodiment, the drive duty determined by drive duty operation section  133  is designated as a drive condition, so that the range of drive duty that can be determined as a drive condition in the event the lower-limit duty value 50% is 50-100%. Furthermore, the range of peak values that can be determined based on the calculation result of drive duty is 50-125 mA ( FIG. 10 ). With the present embodiment, the peak value determined by drive current operation section  134  is designated as a drive condition so that the range of peak values that can be designated as a drive condition when the lower-limit value of duty is 50% is 50 to 125 mA. 
         [0114]    Then, when the lower-limit duty value set in lower-limit duty value setting section  137  changes to 67%, the minimum value of drive duty that can be calculated by drive duty operation section  133  changes to 67%. Consequently, the range of drive duty that can be determined in drive duty operation section  133  changes to 67-100% ( FIG. 9B  or  FIG. 9C ), and the range of drive duty that can be designated as a drive condition becomes 67-100%. Furthermore, the range of peak values that can be determined depending on the drive duty calculation result changes to 50-80 mA ( FIG. 10 ), and the range of peak values that can be designated as a drive condition changes to 50-80 mA. 
         [0115]    By this means, lower-limit duty value setting section  137  changes the designatable range of drive conditions depending on estimated power consumption. 
         [0116]    With the present embodiment, the drive duty that is calculated based on the detected amount of motion and the drive duty that is designated as a drive condition are always equal. Consequently, lower-limit duty value setting section  137  is able to change the lower-limit value of drive duty, which can be calculated based on the detected amount of motion, depending on estimated power consumption, and therefore is able to change the range of drive duty that can be designated depending on estimated power consumption. 
         [0117]    With the present embodiment, a peak value is determined based on a result of calculating drive duty based on a detected amount of motion. Consequently, lower-limit duty value setting section  137  does not actively set the value for limiting the range that can be designated with respect to peak values. Instead, lower-limit duty value setting section  137  is able to change the range of peak values that can be designated, based on estimated power consumption, by setting the lower-limit value of drive duty that is calculated based on the detected amount of motion, depending on estimated power consumption. 
         [0118]    That is to say, with the present embodiment, for both drive duty and peak value that are included in drive conditions, it is possible to change the designatable range based on estimated power consumption. 
         [0119]    Furthermore, lower-limit duty value setting section  137  sets only the lower-limit value, without setting the upper-limit value, with respect to drive duty. If drive duty lowers significantly, the peak value increases significantly in response to this, and cases might occur where this causes the lowering of efficiency of light emission and significant increase of power consumption in light emitting section  121 . Consequently, it is possible to reduce the increase of power consumption in light emitting section  121  by setting the lower-limit value of drive duty alone. 
         [0120]    Consequently, lower-limit duty value setting section  137  sets a higher lower-limit duty value when greater power consumption is estimated. Consequently, when lower power consumption is estimated, a lower-limit duty value is set. Consequently, under the circumstance where video blur is prone to occur such as when the amount of motion in an image is large, it is possible to improve image blur by reducing the drive duty, based on need, based on a detection result of the amount of motion. 
         [0121]    The configuration of liquid crystal display apparatus  100  has been described. 
         [0122]    &lt;1-2. Operation of Liquid Crystal Display Apparatus&gt; 
         [0123]    Next, operations to be executed by liquid crystal display apparatus  100  as a whole (that is, overall operations), and especially the characteristic operations of the present invention, will be described. 
         [0124]    &lt;1-2-1. Overall Operations&gt; 
         [0125]    Examples of overall operations will be described using  FIG. 14  and  FIG. 15 . 
         [0126]      FIG. 14  shows a motion amount detection operation with respect to a series of image signals received as input in liquid crystal panel section  110 . Here, a movie is used as an example in which a pair of black vertical lines on a white background move laterally (hereinafter the longer one will be referred to as “long line” and the shorter one will be referred to as “short line”). For ease of explanation, only partial images in image display areas  11 ,  21 ,  31  and  41  will be described. 
         [0127]    In this example, from the N-th frame to the (N+1)-th frame, the long line moves p1 pixels, and the amount of motion 2.5 is detected in each of image display areas  31  and  41 . Consequently, from the (N+1)-th frame to the (N+2)-th frame, the long line moves p2 pixels and the short line moves p3 pixels, so that the amount of motion 7.5 is detected in image display area  31  and the amount of motion 10 is detected in image display area  41 . 
         [0128]    Here, this example assumes that the power consumption 0.375 is estimated with respect to light emitting section  121 , from the drive duties and peak values determined with respect to individual light emitting areas upon displaying the image of the (N+1)-th frame. 
         [0129]    For example, with reference to  FIG. 13 , lower-limit duty value setting section  137  calculates the lower-limit duty value of 67% following the relationship between power and lower-limit duty value. Thus, the lower-limit duty value calculated from the drive conditions determined with respect to the (N+1)-th frame, is used upon determining the drive conditions for the (N+2)-th frame, as will be explained later. 
         [0130]    Drive duty operation section  133  calculates drive duty based on the detected amount of motion, so as not to fall below the lower-limit duty value 67%, as shown in  FIG. 9B . For example, the drive duty calculated with respect to the detected amount of motion 0 is 100%, and the drive duty calculated with respect to the detected amounts of motion 7.5 and 10 is 67%. 
         [0131]    Then, drive current operation section  134  determines a peak value, based on the calculation result of drive duty, according to the relationship between drive duty and peak value shown in  FIG. 10 , for example. For example, the peak value determined in response to the drive duty 100% is 50 mA and the peak value determined in response to the drive duty 67% is 80 mA. 
         [0132]    In the example shown in  FIG. 14 , with respect to the (N+2)-th frame, the amount of motion detected in image display areas  11  and  21  is 0, the amount of motion detected in image display area  31  is 7.5, and the amount of motion detected in image display area  41  is 10. 
         [0133]    Consequently, upon displaying the image of the (N+2)-th frame, as shown in  FIG. 15 , the drive duty 100% and peak value of 50 mA are designated with respect to light emitting areas  11  and  21  corresponding to image display areas  11  and  21 . Regarding light emitting area  31  corresponding to image display area  31 , a drive duty of 67% and peak value 80 mA are designated, and, for image display area  41  corresponding to image display area  41 , a drive duty of 67% and peak value of 80 mA are designated. 
         [0134]    Consequently, in the example of  FIG. 14 , if the lower-limit duty value is not set on a variable basis, the range of drive duty that can be calculated increases to 50-100%, and the range of peak values that can be determined increases to 50-125 mA ( FIG. 9A  and  FIG. 10 ). Then, as shown in  FIG. 16 , with image display area  41  where the detected amount of motion is 10, the drive duty decreases to 55% and meanwhile the peak value increases to 120 mA. 
         [0135]    As for the range that can be designated with respect to drive conditions, comparing between a case of making the range variable as in  FIG. 15  and a case of making the range not variable as in  FIG. 16 , the power consumption estimated with respect to light emitting area  41  is greater in the non-variable case of  FIG. 16  (80 mAx67%&lt;120 mAx55%). Regarding  FIG. 15  and  FIG. 16 , difference in power consumption is produced only in light emitting area  41 . However, when such difference is observed in a greater number of light emitting areas; the power consumption of light emitting area  121  increases more distinctly. 
         [0136]    Consequently, the range of drive conditions that can be designated is changed based on change of estimated power consumption with respect to light emitting area  121 . By this means, it is possible to reduce the increase of the maximum power consumption of a backlight apparatus including light emitting section  121 . 
       Embodiment 2 
       [0137]    Embodiment 2 of the present invention will be described below. The liquid crystal display apparatus of the present embodiment has the same basic configuration as the liquid crystal display apparatus of the earlier embodiment. Consequently, parts that are the same as in the earlier embodiment or parts that are equivalent to the earlier embodiment will be assigned the same reference numerals without further explanations, and the differences will be mainly explained. 
         [0138]    A case will be described with the present embodiment where a light adjustment value calculation result is reflected in estimation of power consumption, and, based on this estimation result, a lower-limit duty value is set on a variable basis. 
         [0139]    &lt;2-1. Configuration of Liquid Crystal Display Apparatus&gt; 
         [0140]      FIG. 17  shows a configuration of the liquid crystal display apparatus of the present embodiment. Liquid crystal display apparatus  200  has drive control section  230  instead of drive control section  130 . Drive control section  230  is an operation processing apparatus having motion amount detection section  131 , first drive duty operation section  231 , light adjustment value operation section  232 , second drive duty operation section  233 , drive current operation section  134 , scan controller  135 , power estimation section  136  and lower-limit duty value setting section  137 , and controls drive conditions including drive pulse duty and peak value on a per light emitting area basis based on an input image signal of each image display area. First drive duty operation section  231 , second drive duty operation section  233 , drive current operation section  134  and scan controller  135 , combined, constitute a drive condition designating section that designates drive conditions on a per light emitting area basis. 
         [0141]    &lt;2-1-1. First Drive Duty Operation Section&gt; 
         [0142]    First drive duty operation section  231  is basically the same as drive duty operation section  133  of embodiment 1. In particular, the points of calculating drive duty based on a lower-limit duty value set in lower-limit duty value setting section  137  and outputting the calculated drive duty to drive current operation section  134 , are the same. However, there is a difference of outputting the calculated drive duty to second drive duty operation section  233 , not scan controller  135 . 
         [0143]    That is to say, the drive duty that is calculated by first drive duty operation section  231  serves as the base of peak values determined by drive current operation section  134 , do not serve as drive duty to be designated as a drive condition. Second drive duty operation section  233  (which will be described later) determines the drive duty to be designated. 
         [0144]    &lt;2-1-2. Light Adjustment Value Operation Section&gt; 
         [0145]    Light adjustment value operation section  232  performs an operation to calculate the light adjustment value for each light emitting area based on image signals. According to this operation, light adjustment value operation section  232  calculates a greater light adjustment value when an image represented by an image signal is brighter. 
         [0146]    The calculation of light adjustment values based on image signals may be controlled over a full screen or may be controlled on a per area basis. That is to say, in the event of full-screen control, the same light adjustment value is obtained between individual light emitting areas, and, in the event of control on a per area basis, it is possible to calculate different light adjustment values between light emitting areas. In the event of the control per area, the drive duty calculated with respect to a given light emitting area and the light adjustment value calculated with respect to that light emitting areas, are multiplied mutually. 
         [0147]    &lt;2-1-3. Second Drive Duty Operation Section&gt; 
         [0148]    Second drive duty operation section  233  determines a drive duty to designate as a drive condition based on the drive duty calculated by first drive duty operation section  231  and the light adjustment value calculated by light adjustment value operation section  232 . 
         [0149]    To be more specific, second drive duty operation section  233  determines, as a drive duty to designate, the product of the drive duty calculated by first drive duty operation section  231  and the light adjustment value calculated by light adjustment value operation section  232 . 
         [0150]    &lt;2-1-4. Lower-Limit Duty Value Setting Section&gt; 
         [0151]    Lower-limit duty value setting section  137  is different from lower-limit duty value setting section  137  of embodiment 1, as will be explained below. 
         [0152]    When a lower-limit duty value is set based on estimated power consumption, the lower-limit duty value is fed back to first drive duty operation section  231 , and first drive duty operation section  231  calculates drive duty based on this value. For example, when the lower-limit duty value is set to 67% by lower-limit duty value setting section  137 , the minimum value of drive value that can be calculated by first drive duty operation section  231  is 67%. 
         [0153]    With the present embodiment, even when the drive duty calculated by first drive duty operation section  231  is 67%, which matches the lower-limit duty value that is set, this is not necessarily the minimum value in the range that can be designated with respect to drive duty. With the present embodiment, the adjustment light value calculated by light adjustment value operation section  232  falls below 100%, it is possible to make the drive duty to be actually designated as a drive condition lower than 67%. 
         [0154]    Consequently, there are cases where lower-limit duty value setting section  137  of the present embodiment is unable to change the range of drive duty, which can be designated with respect to drive duty, according to changes of estimated power consumption. 
         [0155]    In other words, with the present embodiment, although the lower-limit duty value based on an estimation result of power consumption increases, it is possible to decrease the actual drive duty based on the decrease. 
         [0156]    By the way, peak value is determined based on drive duty calculated by first drive duty operation section  231 . Consequently, when the lower-limit duty value that is set increases, for example, to 67%, and the drive duty that can be calculated by first drive duty operation section  231  increases to 67%, in response to this, the peak value to be determined by drive current operation section  134  decreases to 80 mA. 
         [0157]    Consequently, similar to embodiment 1, lower-limit duty value setting section  137  of the present embodiment is able to change the range of peak values that cane be designated as a drive condition based on change of estimated power consumption. 
         [0158]    In this way, according to the present embodiment, it is possible to change the designatable range of drive conditions based on change of estimated power consumption with respect to light emitting section  121 . Consequently, it is possible to reduce the increase of the maximum power consumption of a backlight apparatus including light emitting section  121 . 
       Embodiment 3 
       [0159]    Embodiment 3 of the present invention will be described now. The liquid crystal display apparatus of the present embodiment has the same basic configuration as the liquid crystal display apparatus of the earlier embodiment. Consequently, parts that are the same as in the earlier embodiment or parts that are equivalent to the earlier embodiment will be assigned the same reference numerals without further explanations, and the differences will be mainly explained. 
         [0160]    A case will be described with the present embodiment where power consumption is estimated from a calculation result of a light adjustment value and a lower-limit value of drive duty is set on a variable basis based on that estimation result. 
         [0161]    &lt;3-1. Configuration of Liquid Crystal Display Apparatus&gt; 
         [0162]      FIG. 18  shows a configuration of a liquid crystal display apparatus according to the present embodiment. Liquid crystal display apparatus  300  has drive control section  330  instead of drive control section  130 . Drive control section  330  is an operation processing apparatus having motion amount detection section  131 , first drive duty operation section  231 , light adjustment value operation section  232 , second drive duty operation section  233 , drive current operation section  134 , scan controller  135 , power estimation section  336  and lower-limit duty value  137 , and controls drive conditions including drive pulse duties and peak values on a per scan area basis based on an input image signal of each image display area. 
         [0163]    &lt;3-1-1. Power Estimation Section&gt; 
         [0164]    Power estimation section  336  performs an operation for estimating power consumption from a calculation result of a light adjustment value. The lower-limit duty value is set in common in all light emitting areas, so that power estimation section  336  estimates the total power consumption of all light emitting areas—that is, the power consumption of light emitting section  121 . 
         [0165]    In this operation, power estimation section  336  ignores change of light emission rate of due to change in light emitting values, estimates the power consumption based on the light adjustment value calculated from an image signal. 
         [0166]    To be more specific, power estimation section  336  acquires the light adjustment value of each light emitting area calculated by light adjustment value operation section  232 . Then, power estimation section  336  acquires an average light adjustment value by calculating an average of the acquired light adjustment values, and estimates this as the power consumption of light emitting section  121 . 
         [0167]    By this means, with the present embodiment, power consumption is estimated based solely on light adjustment value, so that it is possible to estimate power consumption in a more simple manner. 
       Embodiment 4 
       [0168]    Embodiment 4 of the present invention will be described below. The liquid crystal display apparatus of the present embodiment has the same basic configuration as the liquid crystal display apparatus of the earlier embodiment. Consequently, parts that are the same as in the earlier embodiment or parts that are equivalent to the earlier embodiment will be assigned the same reference numerals without further explanations, and the differences will be mainly explained. 
         [0169]    A case will be described with the present embodiment where power consumption estimated from a light adjustment value calculation result is corrected based on a determined peak value, and, based on the corrected estimation result, the lower-limit value of drive duty is set on a variable basis. 
         [0170]    &lt;4-1. Configuration of Liquid Crystal Display Apparatus&gt; 
         [0171]      FIG. 19  shows a configuration of the liquid crystal display apparatus of the present embodiment. Liquid crystal display apparatus  400  has drive control section  430  instead of drive control section  130 . Drive control section  430  is an operation processing apparatus having motion amount detection section  131 , first drive duty operation section  231 , light adjustment value operation section  232 , second drive duty operation section  233 , drive current operation section  134 , scan controller  135 , power estimation section  436  and lower-limit duty value setting section  137 , and controls drive conditions including drive pulse duty and peak value on a per light emitting area basis based on an input image signal of each image display area. 
         [0172]    &lt;4-1-1. Power Estimation Section&gt; 
         [0173]    Power estimation section  436  performs an operation for estimating power consumption from a calculation result of light adjustment value. The lower-limit duty value is set in common in all light emitting areas, so that power estimation section  436  estimates the total power consumption of all light emitting areas—that is, the power consumption of light emitting section  121 . 
         [0174]    In this operation, power estimation section  436  estimates the power consumption of light emitting section  121  taking into account change of light emission rate due to change of peak value. 
         [0175]    To be more specific, power estimation section  436  acquires a light adjustment value in each light emitting area calculated in light adjustment value operation section  232 , and estimates the acquired light adjustment value as the power consumption of each light emitting area. Then, power estimation section  436  calculates an average of the light adjustment values of all light emitting areas (that is, an average light adjustment value), and estimates the average light adjustment value as the power consumption of light emitting section  121 . 
         [0176]    Furthermore, power estimation section  436  acquires the peak value of each light emitting area determined by drive current operation section  134 , and calculates an average of the peak values (that is, an average peak value) of all light emitting areas. 
         [0177]    Then, power estimation section  436  corrects the power consumption of light emitting section  121  by multiplying the power consumption of light emitting section  121  estimated as above, by a correction coefficient to match the average peak value. The corrected, estimated power consumption acquired this way is output to lower-limit duty value setting section  137  and used to set the lower-limit value of duty on a variable basis. 
         [0178]    By this means, with the present embodiment, the power consumption of light emitting section  121  is corrected based on a determined peak value. Consequently, it is possible to estimate power consumption taking into account changes of light emission rate due to change of peak value, and, maintain the accuracy of estimation to a certain level by simple estimation of power consumption. 
       Variation of Embodiment 4 
       [0179]    In the above configuration  4 , power estimation section  436  might correct power consumption before calculating estimated power consumption of light emitting section  121 . Specific descriptions will be described below. 
         [0180]    Power estimation section  436  acquires the light adjustment value of each light emitting area calculated in light adjustment value operation section  232 , and estimates these acquired light adjustment values as the power consumption in each light emitting area. 
         [0181]    Moreover, power estimation section  436  acquires the peak value of each light emitting area (that is, individual peak value) determined by drive current operation section  134 . 
         [0182]    Then, power estimation section  436  corrects the power consumption of each light emitting area by multiplying the power consumption of each light emitting area estimated as above, by a correction coefficient to match each individual peak value. Here, the power consumption in a given light emitting area is multiplied by a correction coefficient to match the peak value of that light emitting area. 
         [0183]    Then, power estimation section  436  calculates an average of power consumption of individual light emitting areas after correction as the estimated power consumption of light emitting section  121 . The estimated power consumption of light emitting section acquired this way is output to lower-limit duty value setting section  137  and used to set the lower-limit duty value on a variable basis. 
         [0184]    By this means, it is possible to improve the accuracy of estimation of simple power consumption estimation. 
       Embodiment 5 
       [0185]    Embodiment 5 of the present invention will be described in detail. The liquid crystal display apparatus of the present embodiment has the same basic configuration as the liquid crystal display apparatus of the earlier embodiment. Consequently, parts that are the same as in the earlier embodiment or parts that are equivalent to the earlier embodiment will be assigned the same reference numerals without further explanations, and the differences will be mainly explained. 
         [0186]    A case will be described with the present embodiment where power consumption estimated from a calculation result of a light adjustment value is corrected based on the amount of motion detected in an image, and, based on the estimation result after correction, sets the lower-limit value of drive duty based on the corrected, estimation result. 
         [0187]    &lt;5-1. Configuration of Liquid Crystal Display Apparatus&gt; 
         [0188]      FIG. 20  shows a configuration of a liquid crystal display apparatus according to the present embodiment. Liquid crystal display apparatus  500  has drive control section  530  instead of drive control section  130 . Drive control section  530  is an operation processing apparatus having motion amount detection section  131 , first drive duty operation section  231 , light adjustment value operation section  232 , second drive duty operation section  233 , drive current operation section  134 , scan controller  135 , power estimation section  536  and lower-limit duty value setting section  137 , and controls drive conditions including drive pulse duty and peak value on a per light emitting area basis based on an input image signal per light emitting area based on an input image signal of each image display area. 
         [0189]    &lt;5-1-1. Power Estimation Section&gt; 
         [0190]    Power estimation section  536  performs an operation for estimating power consumption from a calculation result of a light adjustment value. When the lower-limit duty value is set in common between all light emitting areas, power estimation section  536  estimates the total power consumption of all light emitting areas—that is, the power consumption of light emitting section  121 . 
         [0191]    According to this operation, power estimation section  536  estimates the power consumption of light emitting section  121  taking into account change in light emission rate due to change of peak values. In this regard, power estimation section  536  is the same as power estimation section  436  of embodiment 4. However, since change of the peak value is caused by change in the amount of motion in an image, power estimation section  536  uses the amount of motion in an image to estimate the power consumption of light emitting section  121 . 
         [0192]    To be more specific, power estimation section  536  acquires a light adjustment value in each light emitting area calculated in light adjustment value operation section  232 , and estimates the acquired light adjustment value as the power consumption of each light emitting area. Then, power estimation section  536  calculates an average of the light adjustment values of all light emitting areas (that is, an average light adjustment value), and estimates the average light adjustment value as the power consumption of light emitting section  121 . 
         [0193]    Furthermore, power estimation section  536  acquires the amount of motion of each image display area output from motion amount detection section  131 , and calculates an average of the amounts of motion of all image display areas (that is, average amount of motion). 
         [0194]    Then, power estimation section  536  corrects the power consumption of light emitting section  121 , by multiplying the power consumption of light emitting section  121  estimated as described above, by a correction coefficient to match the average amount of motion. The estimated power consumption acquired this way is output to lower-limit duty value setting section  137  and used to set the lower-limit duty value on a variable basis. 
         [0195]    By this means, with the present embodiment, the estimated power consumption of light emitting section  121  is corrected based on a detected amount of motion. Consequently, it is possible to estimate power consumption taking into account changes of light emission rate due to change of peak value, and, maintain the accuracy of estimation to a certain level by simple estimation of power consumption. 
       Variation of Embodiment 5 
       [0196]    Given the above configuration of embodiment 5, power estimation section  536  may estimate power consumption before calculating estimated power consumption of light emitting section  121 . Specific explanations will be provided below. 
         [0197]    Power estimation section  536  acquires the light adjustment value of each light emitting area calculated by light adjustment value operation section  232 , and estimates the acquired light adjustment values as the power consumption of each light emitting area. 
         [0198]    Moreover, power estimation section  536  acquires the amount of motion in each image display area output from motion amount detection section  131  (that is, individual amount of motion). 
         [0199]    Then, power estimation section  536  corrects the power consumption of each light emitting area by multiplying the power consumption of each light emitting area estimated as above, by a correction coefficient to match each individual amount of motion. Here, the power consumption in a given light emitting area is multiplied by a correction coefficient to match the amount of motion in that light emitting area. 
         [0200]    Then, power estimation section  536  calculates an average of power consumption of individual light emitting areas after correction, as the estimated power consumption of light emitting section  121 . The estimated power consumption of light emitting section  121  acquired this way is output to lower-limit duty value setting section  137  and used to set the lower-limit duty value on a variable basis. 
         [0201]    By this means, it is possible to improve the accuracy of estimation of simple power consumption estimation. 
       Embodiment 6 
       [0202]    Embodiment 6 of the present invention will be described below. The liquid crystal display apparatus of the present embodiment has the same basic configuration as the liquid crystal display apparatus of the earlier embodiment. Consequently, parts that are the same as in the earlier embodiment or parts that are equivalent to the earlier embodiment will be assigned the same reference numerals without further explanations, and the differences will be mainly explained. 
         [0203]    A case will be described with the present embodiment where a light adjustment value calculation result is reflected in estimation of power consumption and based on that estimation result the upper-limit value of peak value is set on a variable basis. 
         [0204]    &lt;6-1. Configuration of Liquid Crystal Display Apparatus&gt; 
         [0205]      FIG. 21  shows a configuration of a liquid crystal display apparatus according to the present embodiment. Liquid crystal display apparatus  600  has drive control section  630  instead of drive control section  130 . Drive control section  630  is an operation processing apparatus having motion amount detection section  131 , first drive duty operation section  631 , light adjustment value operation section  232 , second drive duty operation section  233 , drive current operation section  634 , scan controller  135 , power estimation section  136  and upper-limit current value setting section  638 , and controls drive conditions including drive pulse duty and peak value on a per light emitting area basis based on an input image signal per light emitting area based on an input image signal of each image display area. First drive duty operation section  631 , second drive duty operation section  233 , drive current operation section  634  and scan controller  135 , combined, constitute a drive condition designating section that designates drive conditions on a per light emitting area basis. 
         [0206]    &lt;6-1-1. Drive Current Operation Section&gt; 
         [0207]    Drive current operation section  634  performs an operation for converting the amount of motion of each image display area, which is detected in and output from motion amount detection section  131 , into a peak value for each light emitting area. 
         [0208]    For the method of finding a peak value from the amount of motion, the method to utilize the relationship between the amount of motion and peak value derived from the relationship shown in  FIG. 9A  and  FIG. 10  is an example. The amounts of motion and peak values are related such that a peak value to be determined increases gradually as the detected amount of motion increases. 
         [0209]    Moreover, drive current operation section  634  determines the peak value based on the amount of motion, according to the upper-limit current value fed back from upper-limit current value setting section  638 , so as not to exceed the upper-limit current value. 
         [0210]    Drive current operation section  634  generates current value data, which is a digital signal to represent the determined peak value, and outputs this to illuminating section  120 . By this means, peak values are designated as a drive condition on a per light emitting area basis. 
         [0211]    &lt;6-1-2. First Drive Duty Operation Section&gt; 
         [0212]    First drive duty operation section  631  performs an operation for converting a peak value determined in drive current operation section  634 , into a drive pulse duty value for each light emitting area. First drive duty operation section  631  calculates drive duty per light emitting area, based on the peak value determined per light emitting area. In this operation, the relationship between peak values and drive duty shown in  FIG. 10  can be utilized. 
         [0213]    &lt;6-1-3. Upper-Limit Current Value Setting Section&gt; 
         [0214]    Upper-limit current value setting section  638  performs an operation of calculating and setting the upper-limit current value, which is the upper-limit value of the peak values of individual light emitting areas, from estimated power consumption of light emitting section  121 . Upper-limit current value setting section  638  constitutes a drive condition changing section that changes the designatable range of drive conditions. 
         [0215]    Upper-limit current value setting section  638  sets the upper-limit current value on a variable basis based on estimated power consumption of light emitting section  121 . Estimated power consumption and upper-limit current value are related such the upper-limit current value to be calculated decreases gradually as estimated power consumption increases. 
         [0216]      FIG. 22  shows a method of calculating upper-limit current value based on estimated power consumption, by graphs to show the relationship between power and upper-limit current value. In the example shown in  FIG. 22 , when estimated power consumption is the minimum value 0, the upper-limit current value calculated then is 125 mA, which is the maximum value. The upper-limit current value to be calculated decreases gradually as estimated power consumption increases, and when estimated power consumption is 1 m which is the maximum value, the upper-limit current value calculated then is 50 mA, which is the minimum value. The specific numerical values shown in  FIG. 22  are only examples and can be changed variously. 
         [0217]    The upper-limit current value, once set, is fed back to drive current operation section  634 . Drive current operation section  634  determines the peak value to designate as a drive condition, based on the detected amount of motion, so as not to exceed the fed-back value. 
         [0218]    Consequently, upper-limit current value setting section  638  is able to change the range of peak values that can be designated, according to estimated power consumption, by setting the upper-limit value of peak value that can be determined based on the detected amount of motion, on a variable basis, based on estimated power consumption. 
         [0219]    Upper-limit current value setting section  638  sets the upper-limit value alone for the peak value, without setting the lower-limit value. There are cases where the peak value increases significantly and where in turn the light emission rate of LED  122  decreases significantly or the power consumption of light emitting section  121  increases significantly. Consequently, it is possible to reduce the increase of power consumption in light emitting section  121  by setting the upper-limit value of peak value alone. 
         [0220]    Furthermore, upper-limit current value setting section  638  sets a lower upper-limit current value when greater power consumption is estimated. Consequently, when estimated power consumption is lower, a higher upper-limit current value is set. Consequently, it becomes possible to increase the peak value and in accordance with this decrease drive duty. Consequently, under the circumstance where video blur is prone to occur such as when the amount of motion in an image is large, it is possible to improve image blur by reducing the drive duty, based on need, based on a detection result of the amount of motion. 
       Embodiment 7 
       [0221]    Embodiment 7 of the present invention will be described now. The liquid crystal display apparatus of the present embodiment has the same basic configuration as the liquid crystal display apparatus of the earlier embodiment. Consequently, parts that are the same as in the earlier embodiment or parts that are equivalent to the earlier embodiment will be assigned the same reference numerals without further explanations, and the differences will be mainly explained. 
         [0222]    A case will be described with the present embodiment where an upper-limit value of the amount of motion in an image, which serves as the basis of calculation of drive duty, is set on a variable basis according to estimated power consumption. 
         [0223]    &lt;7-1. Configuration of Liquid Crystal Display Apparatus&gt; 
         [0224]      FIG. 23  shows a configuration of a liquid crystal display apparatus according to the present embodiment. Liquid crystal display apparatus  700  has drive control section  730  instead of drive control section  130 . Drive control section  730  is an operation processing apparatus having motion amount detection section  131 , motion amount correction section  732 , drive duty operation section  733 , drive current operation section  134 , scan controller  135 , power estimation section  136  and upper-limit motion amount setting section  737 , and controls drive conditions including the duties and peak values of drive pulses on a per light emitting area basis based on an input image signal in each image display area. Drive duty operation section  733 , drive current operation section  134  and scan controller  135 , combined, constitute a drive condition designating section that designates drive conditions per light emitting area. 
         [0225]    &lt;7-1-1. Motion Amount Correction Section&gt; 
         [0226]    Motion amount correction section  732  performs an operation for correcting the amount of motion detected per image display area output from motion amount detection section  131  (the amount of motion before correction). 
         [0227]    Motion amount correction section  732  corrects the amount of motion before correction, detected per image display area (that is, corrected amount of motion), to output to drive duty operation section  733 , so as not to exceed the upper-limit value, according to the upper-limit motion amount value set by upper-limit motion amount value setting section  737 . 
         [0228]    Assuming that the upper-limit of the amount of motion is set to 7.5, as shown in  FIG. 24 , motion amount correction section  732  outputs the same value as the amount of value before correction, as the corrected amount of motion, when the amount of motion before correction is 7.5 or less, or outputs 7.5 as the corrected amount of motion singularly if the amount of motion before correction exceeds 7.5. Consequently, in this case, even if the amount of motion before correction is M MAX , the corrected amount of motion is 7.5, not M MAX . 
         [0229]    &lt;7-1-2. Drive Duty Operation Section&gt; 
         [0230]    Drive duty operation section  733  performs an operation for converting an amount of motion, which is detected in and output from motion amount detection section  732 , into a drive pulse duty value for each light emitting area. Drive duty operation section  733  determines the drive duty for each light emitting area, by applying a predetermined conversion formula to the corrected amount of motion acquired per image display area, and determines the result as the drive duty to specify for each light emitting area. 
         [0231]      FIG. 9A  shows one example of a method of calculating drive duty based on the corrected amount of motion. 
         [0232]    &lt;7-1-3. Upper-Limit Motion Amount Setting Section&gt; 
         [0233]    Upper-limit motion amount setting section  737  performs an operation for calculating and setting the upper-limit motion amount value, which is the upper-limit value of the corrected amount of motion per image display area, from estimated power consumption of light emitting section  121 . Upper-limit motion amount setting section  737  constitutes a drive condition changing section to change the range of drive conditions that can be designated. 
         [0234]      FIG. 25  shows a method of calculating the upper-limit motion amount value based on estimated power consumption, by graphs showing the relationship between power and the upper-limit amount of motion. In the example shown in  FIG. 24 , when estimated power consumption is 0, which is the minimum value, the upper-limit amount of motion calculated then is M MAX , which is the maximum value. As estimated power consumption increases, the upper-limit value to be calculated decreases gradually, and, when estimated power consumption is 1, which is the maximum value, the upper-limit value of the amount of motion calculated then is 0, which is the minimum value. For example, when estimated power consumption is 0.375, the upper-limit motion amount value to be calculated becomes 7.5. The specific numerical values shown in  FIG. 24  are only examples and can be changed variously. 
         [0235]    The upper-limit motion amount value, once set, is fed back to motion amount correction section  732 , and motion amount correction section  732  corrects the detected amount of motion based on this value. Then, drive duty operation section  733  calculates drive duty based on the corrected amount of motion output from motion amount correction section  732 , and drive current operation section  134  determines the peak value depending on the drive duty calculated in drive duty operation section  733 . 
         [0236]    For example, when upper-limit motion amount setting section  737  sets the upper-limit value of the amount of motion to M MAX , the range of corrected amounts of motion that can be output from motion amount correction section  732  becomes 0-M MAX . In this case, the range of drive duty that can be determined by drive duty operation section  733  is 50-100% ( FIG. 9A ). With the present embodiment, the drive duty that is determined in drive duty operation section  733  is designated as a drive condition, so that the range of drive duty that can be designated as a drive condition when the upper-limit value of the amount of motion is M MAX  becomes 50-100%. Furthermore, the range of peak values that can be determined based on the drive duty calculation result, is 50-125 mA ( FIG. 10 ). With the present embodiment, the peak value determined by drive current operation section  134  is designated as a drive condition, so that the range of peak values that can be designated as a drive condition when the upper-limit value of the amount of motion is 50-125 mA. 
         [0237]    Then, when the upper-limit value of the amount of motion set by upper-limit motion amount setting section  737  changes to, for example, 7.5, then, the maximum value of the corrected amount of motion that can be output from motion amount correction section  732  changes to 7.5. Consequently, the range of corrected amounts of motion that can be output from motion amount correction section  732  changes to 0-7.5 ( FIG. 24 ). In this case, the range of drive duty that can be designated as a drive condition changes to 67-100% ( FIG. 9A ), and, furthermore, the range of peak values that can be designated as a drive condition changes to 50-80 mA ( FIG. 10 ). 
         [0238]    By this means, upper-limit motion amount setting section  737  changes the rate of drive conditions that can be designated, based on estimated power consumption. 
         [0239]    With the present embodiment, the drive duty that is calculated based on a corrected amount of motion and a drive duty that is designated as a drive condition are always equal. Then, a peak value is determined according to the calculation result of drive duty based on the corrected amount of motion. Consequently, upper-limit motion amount setting section  737  does not actively set the value for limiting the range that can be designated with respect to drive duty and peak values. Instead, upper-limit motion amount setting section  737  is able to change the range of both drive duty and peak values that can be designated, based on estimated power consumption, by setting the upper-limit value of the corrected amount of motion on a variable basis based on estimated power consumption. 
         [0240]    Furthermore, upper-limit motion amount setting section  737  sets the upper-limit value alone, not the lower-limit value, for the corrected amount of motion. If drive duty decreases significantly, the peak value increases significantly in response to this, and cases might occur where this causes the lowering of efficiency of light emission and significant increase of power consumption in light emitting section  121 . Consequently, by setting the upper-limit value of the corrected amount of motion so that excessive decrease of drive duty is prevented, it is possible to reduce the increase of power consumption in light emitting section  121 . 
         [0241]    Furthermore, upper-limit motion amount setting section  737  sets a lower upper-limit motion amount value when greater power consumption is estimated. Consequently, when lower power consumption is estimated, a higher upper-limit motion amount value is set. Consequently, under the circumstance where video blur is prone to occur such as when the amount of motion in an image is large, it is possible to improve image blur by increasing the maximum value of the corrected amount of motion that can be output so that drive duty can be decreased. 
       Embodiment 8 
       [0242]    Embodiment 8 of the present invention will be described below. The liquid crystal display apparatus of the present embodiment has the same basic configuration as the liquid crystal display apparatus of the earlier embodiment. Consequently, parts that are the same as in the earlier embodiment or parts that are equivalent to the earlier embodiment will be assigned the same reference numerals without further explanations, and the differences will be mainly explained. 
         [0243]    A case will be described with the present embodiment where a reduction coefficient for the amount of motion in an image, which serves as the basis of calculation of drive duty, is set on a variable basis, according to estimated power consumption. 
         [0244]    &lt;8-1. Configuration of Liquid Crystal Display Apparatus&gt; 
         [0245]      FIG. 26  shows a configuration of a liquid crystal display apparatus according to the present embodiment. Liquid crystal display apparatus  800  has drive control section  830 , instead of drive control section  130 . Drive control section  830  is an operation processing apparatus having motion amount detection section  131 , motion amount reduction section  832 , drive duty operation section  733 , drive current operation section  134 , scan controller  135 , power estimation section  136  and motion amount reduction coefficient setting section  737 , and controls drive conditions including the duties and peak values of drive pulses on a per light emitting area basis based on an input image signal in each image display area. 
         [0246]    &lt;8-1-1. Motion Amount Reduction Section&gt; 
         [0247]    Motion amount reduction section  832  performs an operation for reducing the detected amount of motion (that is, the amount of motion before reduction) per image display area, output from motion amount detection section  131 . 
         [0248]    Motion amount reduction section  832  reduces the amount of motion before reduction according to the motion amount reduction coefficient set in motion amount reduction coefficient setting section  837 , and outputs the reduced, detected amount of motion per image display area (reduced amount of motion). 
         [0249]    A motion amount reduction coefficient is a function of estimated power consumption, so that p is the estimated power consumption and G(p) [%] is the motion amount reduction coefficient, and motion amount reduction section  832  calculates the reduced amount of motion so that the amount of motion before correction is reduced by G(p) %. Then, as shown in  FIG. 27 , if the amount of correction before reduction is, for example, M MAX , the reduced amount of motion to be output is M MAX ×(100%-G(p)). 
         [0250]    &lt;8-1-2. Motion Amount Reduction Coefficient Setting Section&gt; 
         [0251]    Motion amount reduction coefficient setting section  837  performs an operation of calculating and setting a reduction coefficient for the detected amount of motion per image display area, from the estimated power consumption in light emitting section  121 . Motion amount reduction coefficient setting section  837  constitutes a drive condition changing section that changes the designatable range of drive conditions. 
         [0252]      FIG. 28  shows an example of a method of calculating a motion amount reduction coefficient based on estimated power consumption, by graphs showing the relationships between power and the reduced amount of motion. As stated earlier, the motion amount reduction coefficient, which can be represented as function G(p) of estimated power consumption p, becomes 0%, which is the minimum value, when estimated power consumption is the minimum value 0, or, increasing gradually as estimated power consumption increases, becomes 100% when estimated power consumption is the maximum value 1. 
         [0253]    A motion amount reduction coefficient, once set, is fed back to motion amount reduction section  832 , and motion amount reduction section  832  reduces the detected amount of motion based on this value. Then, drive duty operation section  733  calculates drive duty based on the reduced amount of motion output from motion amount reduction section  832 , and drive current operation section  134  determines the peak value based on the drive duty calculated in drive duty operation section  733 . 
         [0254]    Consequently, when the motion amount reduction coefficient that is set increases or decreases, the magnitude of change, represented by angle θ in  FIG. 27  also changes. As a result, the maximum value of the reduced amount of motion that can be output from motion amount reduction section  832  changes, like the maximum value of the corrected amount of motion that can be output from motion amount correction section  732  ( FIG. 23 ) of embodiment 7. 
         [0255]    Consequently, similar to embodiment 7, without setting the value to limit the designatable range with respect to drive duty and peak value, by setting the reduction coefficient for the detected amount of motion on a variable basis, it is possible to change the designatable range with respect to both drive duty and peak values based on estimated power consumption. 
         [0256]    Also, when greater power consumption is estimated, motion amount reduction coefficient setting section  837  sets a higher motion amount reduction coefficient. Consequently, when lower power consumption is estimated, a lower motion amount reduction coefficient is set. Consequently, under the circumstance where video blur is prone to occur such as when the amount of motion in an image is large, it is possible to improve image blur by increasing the maximum value of the reduced amount of motion that can be output based on need so that drive duty can be decreased. 
         [0257]    Also, according to the present embodiment, drive duty changes in all light emitting areas when the motion amount reduction coefficient changes, and drive conditions do not change locally like described above, so that it is possible to reduce the likelihood of identifying unnecessary flicker due to local change of drive conditions. 
         [0258]    Now, embodiments of the present invention have been described. Note that the above descriptions have encompassed preferred embodiments of the present invention only by way of example and by no means limit the scope of the present invention. That is to say, the configurations and operations of apparatuses described with the above embodiments are examples, and it is obviously and certainly possible to make various changes, additions, and omissions, in part, within the scope of the present invention. 
         [0259]    For example, cases have been described with the above embodiments, by way of example, where the present invention is applied to a liquid crystal display apparatus. However, even if an optical modulation section has a display section that is different from a display section, it is equally possible to employ other configurations insofar as providing a non-self-luminous configuration. That is to say, the present invention is applicable to non-self-luminous display apparatuses other than liquid crystal display apparatuses. 
         [0260]    The above embodiments can be implemented in various combinations. 
         [0261]    The disclosure of Japanese Patent Application No. 2009-228299, filed on Sep. 30, 2009, including the specification, drawings and abstract, is incorporated herein by reference in its entirety. 
       INDUSTRIAL APPLICABILITY 
       [0262]    The backlight apparatus and display apparatus of the present invention provide an advantage of reducing the increase of the maximum power consumption of a backlight apparatus and therefore is useful as a backlight apparatus and display apparatus of a backlight scan scheme. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           100 ,  200 ,  300 ,  400 ,  500 ,  600 ,  700 ,  800  Liquid crystal display apparatus 
           110  Liquid crystal panel section 
           111  Liquid crystal panel 
           112  Source driver 
           113  Gate driver 
           114  Liquid crystal controller 
           120  Illuminating section 
           121  Light emitting section 
           122  LED 
           123  LED driver 
           130 ,  230 ,  330 ,  430 ,  530 ,  630 ,  730 ,  830  Drive control section 
           131  Motion amount detection section 
           133 ,  733  Drive duty operation section 
           134 ,  634  Drive current operation section 
           135  Scan controller 
           136 ,  336 ,  436 ,  536  Power estimation section 
           137  Lower-limit duty value setting section 
           141  Constant current circuit 
           142  Communication OF 
           143  DAC 
           144  Switch 
           151  1V delay section 
           152  Macroblock motion amount operation section 
           153  Maximum value calculation section 
           231 ,  631  First drive duty operation section 
           232  Light adjustment value operation section 
           233  Second drive duty operation section 
           638  Upper-limit current value setting section 
           732  Motion amount correction section 
           737  Upper-limit motion amount setting section 
           832  Motion amount reduction section 
           837  Motion amount reduction coefficient setting section