Abstract:
The present disclosure discloses a 3D display method and a display device, relates to the field of display technologies, and can improve the 3D display effects of a Vertical Alignment (VA) liquid crystal display. The 3D display method comprises the steps of: acquiring effective grayscale of an image to be displayed; acquiring compensation data for brightness of the image to be displayed based on the effective grayscale thereof; and driving, during display of the image, a backlight source based on the compensation data for brightness, so as to compensate for brightness of the image to be displayed. The 3D display method is especially suitable for a VA display device. The present disclosure can be used in a display device, such as a liquid crystal television, a liquid crystal display, a mobile phone, a tablet personal computer, etc.

Description:
[0001]    The present application claims benefit of Chinese patent application CN 201410398419.7, entitled “3D display method and display device” and filed on Aug. 13, 2014, the entirety of which is incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present disclosure relates to the field of display technologies, in particular to a 3D display method and a display device. 
       BACKGROUND OF THE INVENTION 
       [0003]    3D liquid crystal displays (LCDs) not only have the benefits of ultra-thinness, energy conservation, and the like of an LCD, but also allow users to directly discern the distances of the objects in an image, so as to obtain more comprehensive and authentic information. Therefore, 3D LCDs have broad application prospects. 
         [0004]    During operation of an LCD, liquid crystal molecules would be deteriorated under a long-term function of an electric field in one and the same direction. Even if the voltage applied to the liquid crystal molecules is removed, the light transmittance of the liquid crystal molecules may not be restored to a level before application of the voltage, thus causing undesirable phenomena, such as severe blurring of images on the LCD, etc. Therefore, in order to prevent deterioration of liquid crystal molecules, it would be necessary to frequently change the direction of the electric field that is applied to the liquid crystal molecules. 
         [0005]    Based on the forgoing, in order to avoid deterioration of liquid crystal molecules in a 3D LCD and meanwhile ensure the display effects of the 3D LCD, a 3D drive method has been proposed in the prior art, in which the direction of the electric field can be reversed. Specifically, the direction of the electric field is reversed after the left eye image and the right eye image of one picture have both been displayed. 
         [0006]    The inventor has discovered, during the effort for achieving the present disclosure, that the above 3D drive method cannot be applied to a Vertical Alignment (VA) LCD. This is because the pixel of a VA LCD generally employs a charge sharing technology in order to guarantee a large viewing angle display of the VA LCD. That is, one pixel is divided into two sub-pixels, and the large viewing angle display of the VA LCD is achieved by lowering the brightness of either of the two sub-pixels. The above 3D drive method in the prior art would cause unfavorable conditions on the VA LCD, such as different brightness between the left and the right images and crosstalk between the left and right eyes&#39; images on one and the same picture, etc., thus reducing the 3D display effects of the VA LCD and affecting users&#39; experience. 
       SUMMARY OF THE INVENTION 
       [0007]    The technical problem to be solved by the present disclosure is to provide a 3D display method and a 3D display device that can improve 3D display effects of a VA LCD. 
         [0008]    In order to solve the above technical problem, the present disclosure adopts the following technical solutions. 
         [0009]    According to a first aspect of the present disclosure, a 3D display method is provided, comprising the steps of:
       acquiring effective grayscale of an image to be displayed;   acquiring compensation data for brightness of the image to be displayed based on the effective grayscale thereof; and   driving, during display of the image, a backlight source based on the compensation data for brightness, so as to compensate for brightness of the image to be displayed.       
 
         [0013]    The 3D display method further comprises pre-setting the compensation data for brightness of the effective grayscale of the image to be displayed, and storing the same in a compensation lookup table for brightness. 
         [0014]    The compensation data for brightness include intensity of driving current or length of driving time of the backlight source. 
         [0015]    Acquiring the effective grayscale of the image to be displayed includes acquiring the grayscale that occupies the largest area in the image to be displayed as the effective grayscale, preferably acquiring the grayscale that occupies the largest area in the middle of the image to the displayed as the effective grayscale. 
         [0016]    Acquiring the effective grayscale of the image to be displayed includes acquiring the effective grayscale of the image to be displayed every other frame. 
         [0017]    The technical solution provided in the embodiments of the present disclosure discloses a 3D display method, through which specific compensation for brightness of a picture displayed on a display device can be performed. Specifically, corresponding compensation data for brightness can be acquired based on the effective grayscale of an image to be displayed, and the brightness of the image to be displayed can be compensated for by using the acquired compensation data for brightness during display of the image. This method is beneficial for ensuring the same brightness of the left and right images on one and the same picture, thus preventing occurrence of undesirable conditions, such as crosstalk between the left and right eyes&#39; images, etc. As a result, the 3D display effects of the VA LCD can be guaranteed, and users&#39; experience can be improved. 
         [0018]    According to a second aspect of the present disclosure, a 3D display device is provided, comprising:
       a first acquisition module, used for acquiring effective grayscale of an image to be displayed;   a second acquisition module, used for acquiring compensation data for brightness of the image to be displayed based on the effective grayscale thereof; and   a driving module, used for driving, during display of the image, a backlight source based on the compensation data for brightness, so as to compensate for brightness of the image to be displayed.       
 
         [0022]    The 3D display device further comprises a setting and storage module, used for pre-setting the compensation data for brightness of the effective grayscale of the image to be displayed, and storing the same in a compensation lookup table for brightness. 
         [0023]    The compensation data for brightness include intensity of driving current or length of driving time of the backlight source. 
         [0024]    The first acquisition module is specifically used for acquiring the grayscale that occupies the largest area in the image to be displayed as the effective grayscale, preferably for acquiring the grayscale that occupies the largest area in the middle of the image to be displayed as the effective grayscale. 
         [0025]    The first acquisition module is specifically used for acquiring the effective grayscale of the image to be displayed every other frame. 
         [0026]    Other features and advantages of the present disclosure will be further explained in the following description, and partly become self-evident therefrom, or be understood through implementing the embodiments of the present disclosure. The objectives and advantages of the present disclosure will be achieved through the structure specifically pointed out in the description, claims, and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    In order to explain the technical solution in the embodiments of the present disclosure in a clearer manner, the accompanying drawings used in the following description will be briefly explained, in which: 
           [0028]      FIG. 1  schematically shows a flowchart I of a 3D display method according to the embodiments of the present disclosure; 
           [0029]      FIG. 2  schematically shows a flowchart II of the 3D display method according to the embodiments of the present disclosure; 
           [0030]      FIG. 3  schematically shows reversion of the direction of an electric field according to the embodiments of the present disclosure; 
           [0031]      FIG. 4  schematically shows display brightness before compensation according to the embodiments of the present disclosure; 
           [0032]      FIG. 5  shows a diagram I of the driving effects of a backlight source according to the embodiments of the present disclosure; 
           [0033]      FIG. 6  shows a diagram II of the driving effects of the backlight source according to the embodiments of the present disclosure; 
           [0034]      FIG. 7  schematically shows the display brightness after compensation according to the embodiments of the present disclosure; and 
           [0035]      FIG. 8  schematically shows the structure of a 3D display device according to the embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0036]    The present disclosure will be explained by reference to the following detailed description of embodiments taken in connection with the accompanying drawings, whereby it can be readily understood how to solve the technical problem by the technical means according to the present disclosure and achieve the technical effects thereof, and thus the technical solution according to the present disclosure can be implemented. It is important to note that as long as there is no conflict, combinations of the above-described embodiments and of technical features therein are possible, and technical solutions obtained in this manner are intended to be within the scope of the present disclosure. 
       Embodiment One 
       [0037]    This embodiment of the present disclosure provides a 3D display method. As FIG.  1  shows, the 3D display method can comprise the following steps. 
         [0038]    In step S 101 , the effective grayscale of an image to be displayed is acquired. 
         [0039]    In this embodiment of the present disclosure, the image to be displayed refers to an image which has been read out but not yet output or displayed by a display device. Specifically, the grayscale that occupies the largest area in the image to be displayed can be acquired as the effective grayscale. Preferably, the grayscale that occupies the largest area in the middle of the image to be displayed can be acquired as the effective grayscale. Obviously, there can be a plurality of methods for acquiring the effective grayscale, which are not be restricted by this embodiment of the present disclosure. 
         [0040]    In step S 102 , a compensation data for brightness of the image to be displayed is acquired based on the effective grayscale thereof. 
         [0041]    In step S 103 , during display of the image, a backlight source is driven based on the compensation data for brightness, so as to compensate for brightness of the image. 
         [0042]    In order to guarantee a large viewing angle display of a VA display device, the pixel of the VA display device can generally employ a charge sharing technology. That is, one pixel can be divided into two sub-pixels, and the large viewing angle display of the VA LCD can be achieved by lowering the brightness of either of the two sub-pixels. If a conventional 3D display method is used, in which the direction of an electric field is reversed after the left and right eyes&#39; images of one and the same picture are displayed, different brightness between the left and right images of one and the same picture would arise on the VA display device, thus resulting in unfavorable conditions, such as crosstalk between the left and right eyes&#39; images, etc. 
         [0043]    Therefore, this embodiment of the present disclosure discloses a 3D display method, through which specific compensation for brightness of a picture displayed on a display device can be performed. Specifically, corresponding compensation data for brightness can be acquired based on the effective grayscale of the image to be displayed, and during display of the image, the brightness of the image to be displayed can be compensated for by using the acquired compensation data for brightness. This method is beneficial for ensuring the same brightness of the left and right images on one and the same picture, thus preventing occurrence of unfavorable conditions, such as crosstalk between the left and right eyes&#39; images and the like. As a result, the 3D display effects of the VA LCD can be guaranteed, and users&#39; experience can be improved. 
         [0044]    Further, the 3D display method disclosed by this embodiment of the present disclosure can comprise the following step before step S 101 , as  FIG. 2  shows. 
         [0045]    In step S 201 , the compensation data for brightness of the effective grayscale of the image to be displayed can be pre-set and stored in a compensation lookup table for brightness. 
         [0046]    In the present embodiment of the present disclosure, the compensation data for brightness can be intensity of driving current, or length of driving time of the backlight source. 
         [0047]    Generally, each 3D picture displayed can comprise two frames of images, i.e., a left-eye image and a right-eye image, respectively. The left-eye image and right-eye image may have a slight difference therebetween, and are taken or processed according to a parallax angle which exists between a user&#39;s left eye and right eye at the time of observing one and the same object. Thus, only when the left-eye image and the right-eye image can both be normally displayed at a high quality, can the user observe ideal 3D display effects on the display device. 
         [0048]    Therefore, step S 201  can comprise: pre-setting the compensation data for brightness of the left eye based on the effective grayscale of the left-eye image to be displayed, and storing the same in a compensation lookup table for brightness of the left eye; and pre-setting the compensation data for brightness of the right eye based on the effective grayscale of the right-eye image to be displayed, and storing the same in a compensation lookup table for brightness of the right eye. 
         [0049]    Specifically, in this embodiment of the present disclosure, an ideal brightness value can be pre-set as actually required. Subsequently, the brightness of the left-eye image and the right-eye image of each effective grayscale on a VA display device under a 3D mode can be obtained. The gap between the brightness of each left-eye image and the ideal brightness value can be calculated to obtain backlight compensation data for brightness of the left eye image corresponding to each left-eye brightness gap. The obtained backlight compensation data for brightness of the left eye can be stored in a compensation look-up table for brightness of the left eye as shown in table 1 that follows, and referred to by the display device when compensating for the brightness of the left-eye image. 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Effective 
                 Intensity of driving 
                 Length of driving 
               
               
                 grayscale 
                 current (left) 
                 time (left) 
               
               
                   
               
             
             
               
                 0 
                 IL0 
                 TL0 
               
               
                 1 
                 IL1 
                 TL1 
               
               
                 2 
                 IL2 
                 TL2 
               
               
                 3 
                 IL3 
                 TL3 
               
               
                 . . . 
                 . . . 
                 . . . 
               
               
                 254  
                  IL254 
                  TL254 
               
               
                 255  
                  IL255 
                  TL255 
               
               
                   
               
             
          
         
       
     
         [0050]    Similarly, through calculation of the gap between the brightness of each right-eye image and the ideal brightness value, backlight compensation data for brightness of each right-eye image can be obtained. The obtained backlight compensation data can be stored in a compensation look-up table for brightness of the right eye image as shown in table 2 that follows, and referred to by the display device when compensating for the brightness of the right-eye image. 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 Effective 
                 Intensity of driving 
                 Length of driving 
               
               
                 grayscale 
                 current (right) 
                 time (right) 
               
               
                   
               
             
             
               
                 0 
                 IR0 
                 TR0 
               
               
                 1 
                 IR1 
                 TR1 
               
               
                 2 
                 IR2 
                 TR2 
               
               
                 3 
                 IR3 
                 TR3 
               
               
                 . . . 
                 . . . 
                 . . . 
               
               
                 254  
                  IR254 
                  TR254 
               
               
                 255  
                  IR255 
                  TR255 
               
               
                   
               
             
          
         
       
     
         [0051]    A current image to be displayed can be either a left-eye image or a right-eye image. Therefore, in step S 102 , the compensation data for brightness of the left eye corresponding to the effective grayscale can be acquired when the image to be displayed is judged as a left-eye image. 
         [0052]    Subsequently, in step S 103 , a backlight source can be driven based on the compensation data for brightness of the left eye during display of the image, so as to compensate for brightness of the image to be displayed. 
         [0053]    Obviously, in step S 102 , the compensation data for brightness of the right eye corresponding to the effective grayscale can also be acquired when the image to be displayed is judged as a right-eye image. 
         [0054]    Subsequently, in step S 103 , a backlight source can be driven based on the compensation data for brightness of the right eye during display of the image, so as to compensate for brightness of the image to be displayed. 
         [0055]    For example, the left-eye image and right-eye image together constitute each 3D picture that is displayed, and the electric fields of two pictures displayed in succession are of opposite directions, as  FIG. 3  shows. A first picture and a second picture will be explained as an example in the following. Since the electric fields displaying the first and second pictures are of opposite directions, a reversion of electric field direction must take place after displaying the right-eye image of the first picture and before displaying the left-eye image of the second picture. Due to the role of the charge sharing technology in the VA display device, the reversion of the electric field will lead to such a small amount of charge carried by a pixel electrode of the display device that the liquid crystal molecules cannot be adequately driven. This would render the brightness of the left-eye image of the second picture rather dim, as  FIG. 4  shows, while the right-eye image of the second picture can be normally displayed. 
         [0056]    The left-eye image of the second picture, after being read out by the display device and before being output by the display device, will be an image to be displayed by the display device. The image to be displayed will be judged as a left-eye image or a right-eye image, and the effective grayscale thereof will be obtained. After the image to be displayed is judged to be a left-eye image by the display device, corresponding compensation data for brightness of the left eye can be obtained from the compensation lookup table for brightness of the left eye based on the effective grayscale. Correspondingly, the compensation data for brightness at this moment is in the form of the intensity of driving current of the backlight source. As a result, the display brightness of the left-eye image of the second picture can be improved. 
         [0057]    Correspondingly, the right-eye image of the second picture, after being read out by the display device and before being output by the display device, will be an image to be displayed by the display device. The image to be displayed will be judged as a left-eye image or a right-eye image, and the effective grayscale thereof will be obtained. After the image to be displayed is judged to be a right-eye image by the display device, corresponding compensation data for brightness of the right eye can be obtained from the compensation lookup table for brightness of the right eye based on the effective grayscale. Correspondingly, the compensation data for brightness of the right eye at this moment is in the form of the intensity of driving current of the backlight source. As a result, the display brightness of the right-eye image of the second picture can be improved. 
         [0058]    As shown in  FIG. 5 , after compensation, the brightness of the backlight source during display of the left-eye image of the second picture can be greater than that of the backlight source during display of the right-eye image of the second picture. 
         [0059]    In addition, the compensation data for brightness may also be the length of driving time of the backlight source. As shown in  FIG. 6 , obviously, the backlight source for the left-eye image and that for the right-eye image of the second picture have the same brightness at this moment. However, influenced by the compensation data for brightness, the illumination duration of the backlight source is longer when the left-eye image is displayed than when the right-eye image is displayed. 
         [0060]      FIG. 7  shows the display effects after compensation for the condition of  FIG. 4  by the manner shown in  FIG. 5  or  FIG. 6 . It is obvious that at this moment, the left-eye image and the right-eye image substantially have the same brightness for users, thus ensuring the users&#39; viewing effects. However, it should be noted that, in this case, the display brightness of  FIG. 4  will be greater after being compensated by the manner shown in  FIG. 6  than being compensated by the manner shown in  FIG. 5 . 
         [0061]    It should be noted that, as an example, the first image frame of each picture has been explained as a left-eye image in the above. Obviously, the first image frame of each picture may also be a right-eye image. This will not be limited by the embodiment of the present invention. 
         [0062]    According to the foregoing description, for a VA display device, the direction of the electric field would be reversed after the display of each picture is completed, so that the brightness of the first image frame of each picture will be reduced, while the brightness of the second image frame can be normal; that is, the brightness of the first image frame is smaller than that of the second image frame. Thus, it will be only necessary to compensate for the brightness of the first image frame or the second image frame of each picture, so as to render the brightness of the first image frame and that of the second image frame equal. 
         [0063]    In this case, step S 101  can comprise acquiring the effective grayscale of the image to be displayed every other frame. That is, steps S 102  and S 103  can be performed after acquiring the effective grayscale of only the first image frame or the second image frame. 
         [0064]    It is obvious that the first image frame can be either a left-eye image or a right-eye image. Correspondingly, the second image frame can also be either a right-eye image or a left-eye image. Thus, if compensation is only necessary for brightness of the first image frame, it needs to determine whether the first image frame is a left-eye image or a right-eye image. Subsequently, the corresponding compensation data for brightness can be obtained based on the determination result, and the backlight source during display of the first image frame can be driven based on the compensation data for brightness, thereby compensating for the brightness of the first image frame. In this case, the brightness of the second image frame may not be processed. It can be ensured that the difference in brightness between the first image frame and the second image frame can be reduced or eliminated as long as the backlight source is normally driven, thus ensuring users&#39; 3D viewing effects. 
       Embodiment Two 
       [0065]    This embodiment provides a 3D display device as shown in  FIG. 8 . The 3D display device can comprise a first acquisition module, which can be used for acquiring effective grayscale of an image to be displayed. 
         [0066]    The first acquisition module can be specifically used for acquiring the grayscale that occupies the largest area in the image to be displayed as the effective grayscale, preferably for acquiring the grayscale that occupies the largest area in middle of the image to be displayed as the effective grayscale. 
         [0067]    The 3D display device can also comprise a second acquisition module, which can be used for acquiring compensation data for brightness of the image to be displayed based on the effective grayscale thereof. 
         [0068]    The 3D display device can further comprise a driving module, which can be used for driving, during display of the image, a backlight source based on the compensation data for brightness, so as to compensate for brightness of the image. 
         [0069]    As  FIG. 8  indicates, the 3D display device can further comprise a setting and storage module, which can be used for pre-setting the compensation data for brightness of the effective grayscale of the image to be displayed, and storing the same in a compensation lookup table for brightness. 
         [0070]    In the embodiment of the present disclosure, the compensation data for brightness can include intensity of driving current or length of driving time of the backlight source. 
         [0071]    Generally, each 3D picture displayed can comprise two frames of images, i.e., a left-eye image and a right-eye image, respectively. The left-eye image and right-eye image may have a slight difference therebetween, and are taken or processed according to a parallax angle which exists between a user&#39;s left eye and right eye at the time of observing one and the same object. Thus, only when the left-eye image and the right-eye image can both be normally displayed at a high quality, can the user observe ideal 3D display effects on the display device. 
         [0072]    Therefore, the setting and storage module can be specifically used for pre-setting the compensation data for brightness of the left eye based on the effective grayscale of the left-eye image to be displayed, and storing the same in a compensation lookup table for brightness of the left eye, and also for pre-setting the compensation data for brightness of the right eye based on the effective grayscale of the right-eye image to be displayed, and storing the same in a compensation lookup table for brightness of the right eye. 
         [0073]    Since a current image to be displayed can be either a left-eye image or a right-eye image, as  FIG. 8  shows, the 3D display device can further comprise a judgment module, which can be used for judging whether the image to be displayed is a left-eye image or a right-eye image. 
         [0074]    Hence, if the judgment module determines the image to be displayed as a left-eye image, the second acquisition module will be used for obtaining, from the setting and storage module, compensation data for brightness of the left eye corresponding to the effective grayscale, while the driving module will be used for, during display of the image, driving the backlight source based on the acquired compensation data for brightness of the left eye. 
         [0075]    Alternatively, if the judgment module determines the image to be displayed as a right-eye image, the second acquisition module will be used for obtaining, from the setting and storage module, compensation data for brightness of the right eye corresponding to the effective grayscale, while the driving module will be used for, during display of the image, driving the backlight source based on the acquired compensation data for brightness of the right eye. 
         [0076]    For a VA display device, after the direction of electric field is changed, the brightness of the first image frame of each picture will be reduced, while the brightness of the second image frame can be normal; that is, the brightness of the first image frame is smaller than that of the second image frame. Thus, it will be only necessary to compensate for the brightness of the first image frame or the second image frame of each picture, so as to render the brightness of the first image frame and that of the second image frame equal. 
         [0077]    The first acquisition module can further be specifically used for acquiring the effective grayscale of the image to be displayed every other frame. 
         [0078]    While the embodiments of the present disclosure are described above, the description should not be construed as limitations of the present disclosure, but merely as embodiments for readily understanding the present disclosure. Anyone skilled in the art, within the spirit and scope of the present disclosure, can make amendments or modification to the implementing forms and details of the embodiments. Hence, the scope of the present disclosure should be subjected to the scope defined in the claims.