Abstract:
A system and a method of compensating background brightness for a display apparatus are disclosed. The display apparatus has a screen for displaying images, and said method comprises steps of: (a) detecting an intensity of ambient light in the front of the screen; (b) obtaining a representative brightness of an image displayed on the screen; (c) determining a backside spotting reference reflective luminance value according to the ambient light intensity and the image representative brightness; and (d) spotting in the rear of the screen by using a lighting module and thus making a spotting intensity to achieve the reference reflective luminance value. The said method and system can reduce eye fatigue and discomfort of viewers.

Description:
CLAIM OF PRIOIRTY 
       [0001]    This application claims priority to Taiwanese Patent Application No. 100101491 filed on Jan. 14, 2011. 
       TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present invention relates to a background brightness compensating method and system, and more particularly, to a background brightness compensating method and system for a display apparatus. 
       BACKGROUND OF THE INVENTION 
       [0003]    Display apparatuses are successively improved with image quality as the quality demand is significantly increased for users. In current display products, some display apparatuses are equipped with a function for adjusting screen brightness based on ambient light; while some improvements are seeking for a better image performance, the others are focused on power saving. 
         [0004]    However, there is not enough emphasis being put on developing an eyecare function for conventional display apparatuses, such that in a situation where a display apparatus is used in an indoor environment, a screen of the display apparatus may be a little dazzle when the ambient light is too bright. Although a better color performance will be presented when the ambient light is dark, the images displayed on the screen may be considerably bright relative to a wall behind the display apparatus. Such strong contrast may easily cause eye fatigue and discomfort for viewers. 
         [0005]    Therefore, improving the above disadvantages of the conventional display apparatuses, designing a system to compensate the deficiency of the conventional display apparatuses, and developing a display apparatus which is equipped with the eyecare function, are important aspects to improve the problems of this industry. 
       SUMMARY OF THE INVENTION 
       [0006]    An objective of the present invention is to provide a background brightness compensating method and system for a display apparatus to improve viewing comfort for users. 
         [0007]    Another objective of the present invention is to provide a background brightness compensating method and system for a display apparatus for reducing eye fatigue and discomfort when the eyes are kept on a screen for a long time, and when the user is in a dark environment or ambient light is altered drastically. 
         [0008]    According to the above objectives, the present invention provides a method of compensating background brightness for a display apparatus, the display apparatus having a screen for displaying images, and said method comprises steps of: (a) detecting an intensity of ambient light in the front of the screen; (b) obtaining a representative brightness of an image displayed on the screen; (c) determining a backside spotting reference reflective luminance value according to the ambient light intensity and the image representative brightness; and (d) spotting in the rear of the screen by using a lighting module and thus making a spotting intensity to achieve the reference reflective luminance value. 
         [0009]    In another aspect, the present invention provides a background brightness compensating system for a display apparatus. The display apparatus has a screen for displaying images, and said system comprises a first light sensor, a second light sensor, a lighting module, and a controller. The first light sensor is disposed in a front position with respect to the display apparatus for detecting an intensity of ambient light in the front of the screen. The second light sensor is disposed in a rear position with respect to the display apparatus for detecting a reflective luminance of background in the rear of the screen. The lighting module is utilized to spot in the rear of the screen for compensating the reflective luminance of background behind the screen. The controller is coupled to the first light sensor, the second light sensor, and the lighting module, for determining a backside spotting reference reflective luminance value according to the ambient light intensity detected by the first light sensor and a representative brightness of an image displayed on the screen. The controller also outputs a control signal to adjust an illumination intensity of the lighting module and thus makes the reflective luminance of background detected by the second light sensor to achieve the reference reflective luminance value. 
         [0010]    The present invention utilizes to adjust the illumination intensity of the lighting module according to the image brightness on the screen and the ambient light intensity in a place where a user is located, for spotting in the rear of the screen, and in such manner that an encompassing light halo of an appropriate intensity is formed on a background wall so as to carry out the background brightness compensation. Therefore, when a user is in a dark environment or the ambient light is altered drastically, the present invention is capable of reducing eye fatigue and discomfort for viewers by adjusting the illumination intensity of the lighting module in an appropriate time to change the background reflective light. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The present invention will be described in details in conjunction with the appending drawings. 
           [0012]      FIG. 1  is a flow chart illustrating a method of compensating background brightness for a display apparatus according to the present invention. 
           [0013]      FIG. 2A  is a perspective view of a background brightness compensating system according to the present invention. 
           [0014]      FIG. 2B  is a rear view of the background brightness compensating system shown in  FIG. 2A . 
           [0015]      FIG. 3  is a schematic block diagram showing a compensation mechanism of the background brightness compensating system shown in  FIGS. 2A and 2B . 
           [0016]      FIG. 4  is a perspective view of a background brightness compensating system for a display apparatus according to another embodiment of the present invention. 
           [0017]      FIG. 5A  is a perspective view of a display apparatus implemented according to the present invention. 
           [0018]      FIG. 5B  is a rear view of the display apparatus shown in  FIG. 5A . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    Please refer to  FIG. 1  to  FIG. 3 .  FIG. 1  is a flow chart illustrating a method of compensating background brightness for a display apparatus according to the present invention.  FIG. 2A  is a perspective view of a background brightness compensating system according to the present invention.  FIG. 2B  is a rear view of the background brightness compensating system of the present invention.  FIG. 3  is a schematic block diagram showing a compensation mechanism of the background brightness compensating system shown in  FIGS. 2A and 2B . The present invention will be detailedly described as follows and by referring the flow chart of the background brightness compensating method shown in  FIG. 1  in accompany with  FIGS. 2A ,  2 B, and  FIG. 3 . 
         [0020]    As shown in  FIGS. 2A ,  2 B, and  FIG. 3 , the display apparatus  1  can be divided into a front portion  12  and a backside portion  14  opposite to the front portion  12 . The front portion  12  has a screen  120  disposed thereon for displaying images and the screen  120  is surrounded by a side frame  125 . The backside portion  14  of the display apparatus  1  has a power socket  142  and a video connection port (not shown) disposed thereon. The background brightness compensating system mainly includes a lighting module  2 , a first light sensor  51 , a second light sensor  52 , and a controller  80 . The first light sensor  51  can be disposed in an appropriate front position with respect to the display apparatus  1  for detecting an intensity of ambient light in the front of the screen  120 ; the second light sensor  52  can be disposed in an appropriate rear position with respect to the display apparatus  1  for detecting a reflective luminance of background in the rear of the screen  120 . In one embodiment, the first light sensor  51  is disposed on the side frame  125  of the front portion  12  of the display apparatus  1  and the second light sensor  52  is disposed in an appropriate position of the backside portion  14  of the display apparatus  1 . The lighting module  2  includes a reflective plate  22  and at least a light source  21 , such as a light emitting diode (LED). The lighting module  2  is arranged for spotting in the rear of the screen  120  to compensate the reflective luminance of background behind the screen  120 . The lighting module  2  is utilized for spotting along a direction far away from the screen  120  and in such manner that an encompassing light halo of an appropriate intensity is formed on a wall so as to carry out the background brightness compensation. The controller  80  is utilized to adjust an illumination intensity of the lighting module  2  to tune the reflective luminance of background appropriately, in the rear of the screen  120 . 
         [0021]    In addition, the background brightness compensating system may also include an adjustable support bracket  25  and at least a spotting reflective plate  3 . The adjustable support bracket  25  is assembled with the lighting module  2  for supporting the lighting module  2  and adjusting an angular position of the lighting module  2  so as to change its spotting angle. The spotting reflective plate  3  is disposed on side edges around the display apparatus  1 . Between the spotting reflective plate  3  and the side edges of the display apparatus  1 , a movable hinge  35  can be utilized to be assembled. The spotting reflective plate  3  can be rotated to adjust its angular position through the movable hinge  35  and thereby changing a distribution of the light halo. 
         [0022]    In the present invention, the controller  80  is able to adjust the illumination intensity of the lighting module  2  according to the detected ambient light intensity in the front of the screen  120  by the first light sensor  51  and a representative brightness of an image displayed on the screen  120  for compensating the reflective luminance of background behind the screen  120 . Therefore, when watching the screen  120  for a long time, a viewer may not feel tired easily. The background brightness compensating method of the present invention will be described as follows. 
         [0023]    In Step S 10 , the display apparatus  1  and the background brightness compensating system are powered up to enable a compensation function for the background brightness. 
         [0024]    In Step S 12 , the first light sensor  51  detects an intensity of ambient light in the front of the screen  120  and then transmits a detected intensity value of the ambient light to the controller  80 . 
         [0025]    In Step S 14 , it is to obtain a representative brightness of an image displayed on the screen  120 . As shown in  FIG. 3 , the controller  80  may receive, via a display chip  72 , those pixel data and brightness information inputted to the display apparatus, and obtain the image representative brightness by performing a computation of the pixel data and brightness information for each frame. 
         [0026]    In Steps S 16  and S 18 , the controller  80  determines a backside spotting reference reflective luminance value according to the detected ambient light intensity in the front of the screen  120  by the first light sensor  51  and the image representative brightness displayed on the screen  120 . The backside spotting reference reflective luminance value may be determined according to a lookup table. The lookup table may be stored in a memory  81  (see  FIG. 3 ) beforehand. The lookup table contains records of different combinations of the ambient light intensity and the image representative brightness, and the reference reflective luminance value corresponding to each combination. The lookup table can be made according to a specific function or an experimental result based on comfortable or suitable luminance ranges for human eye perception in consideration of relations between the image representative brightness, the ambient light intensity, and a fatigue level of eyes. Also, the system of the present invention may be setup to have several background brightness compensation modes to be selected by users themselves, or allow users to define or assign a reflective luminance of background and this brightness value is stored in the memory  81  via the controller  80 . 
         [0027]    In Step S 20 , the second light sensor  52  detects a reflective luminance of background in the rear of the screen  120  and then transmits the detected reflective luminance of background to the controller  80 . 
         [0028]    In Step S 22 , the controller  80  compares the detected reflective luminance of background in the rear of the screen  120  by the second light sensor  52  with the backside spotting reference reflective luminance value to determine whether the reflective luminance of background achieves the reference reflective luminance value or not. 
         [0029]    In Step S 24 , when the reflective luminance of background is inconsistent with the reference reflective luminance value, the controller  80  outputs a control signal (CS) to adjust an illumination intensity of the lighting module  2 . In this step, the controller  80  may gradually adjust the illumination intensity of the lighting module  2  in a piecewise adjustment to prevent the reflective luminance of background from suddenly changing and thereby preventing a disturbance of eye comfort. 
         [0030]    When the second light sensor  52  detects the reflective luminance of background in the rear of the screen  120  to achieve the backside spotting reference reflective luminance value, it is an indication that a current reflective luminance of background has been adjusted to a suitable reflective luminance. When the image brightness on the screen  120  is changed or the illumination in an environment where a user is located is altered, the controller  80  will automatically adjust the illumination intensity of the lighting module  2  again to alter the reflective luminance of background behind the screen  120 . 
         [0031]    The present invention utilizes to adjust the illumination intensity of the lighting module  2  according to the image brightness on the screen  120  and the ambient light intensity in a place where a user is located, for spotting in the rear of the screen  120 , and in such manner that an encompassing light halo of an appropriate intensity is formed on a background wall so as to carry out the background brightness compensation. Therefore, when a user is in a dark environment and the image presented on the screen  120  is relatively brighter, by compensating the reflective luminance of background in the rear of the screen  120 , the present invention is capable of reducing eye fatigue for viewers. Further, the present invention can adjust the illumination intensity of the lighting module  2  in an appropriate time so as to change the reflective luminance of background. When the ambient light is altered drastically, the present invention can reduce the eye fatigue as well. 
         [0032]      FIG. 4  is a perspective view of a background brightness compensating system for a display apparatus according to another embodiment of the present invention. The difference between the background brightness compensating system shown in  FIG. 4  and the embodiment illustrated in  FIG. 1  is that the background brightness compensating system in this embodiment further includes a diffusion plate  6  disposed on an illumination path of an lighting module  2   a  (including a reflective plate  22   a  and at least a light source  21   a ) for diffusing light beams emitted from the lighting module  2   a,  and in such manner that an encompassing light halo is formed more uniformly on a background wall and the compensation effect of background brightness is more preferred. In addition, the diffusion plate  6  also can be arranged in combination with a color filter so as to illuminate with a specific color, and thereby improving the atmosphere. 
         [0033]      FIG. 5A  is a perspective view of a display apparatus implemented according to the present invention.  FIG. 5B  is a rear view of the display apparatus shown in  FIG. 5A . For the display apparatus  1   b  shown in  FIGS. 5A and 5B , the first light sensor  51  is disposed on the side frame  125  of the front portion  12  of the display apparatus  1   b  and the second light sensor  52  is disposed on the backside portion  14  of the display apparatus  1   b.  Further, the lighting module  2   a  can be assembled to the backside portion  14  of the display apparatus  1   b  in an appropriate position. The controller (not shown) can be arranged together with a circuit board inside the display apparatus  1   b.  In addition, the display apparatus  1   b  may include at least a detachable spotting reflective plate  3 . 
         [0034]    The present invention is not limited to be applied to a particular type of display apparatus. Those conventional 2D flat panel displays, developing 3D stereoscopic displays, and integrated 2D/3D displays all are within the scope of the present invention. For example, the display apparatus of the present invention can be implemented by liquid crystal displays (LCDs), organic light emitting displays (OLEDs), plasma display panels (PDPs), field emission displays (FEDs), and the likes. Further, the present invention can be implemented by stereoscopic displays with glasses or without glasses. 
         [0035]    While the preferred embodiments of the present invention have been illustrated and described in detail, various modifications and alterations can be made by persons skilled in this art. The embodiment of the present invention is therefore described in an illustrative but not restrictive sense. It is intended that the present invention should not be limited to the particular forms as illustrated, and that all modifications and alterations which maintain the spirit and realm of the present invention are within the scope as defined in the appended claims.