Patent Publication Number: US-10789882-B2

Title: Optical compensation apparatus applied to panel and operating method thereof

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a panel; in particular, to an optical compensation apparatus applied to the panel and an operating method thereof. 
     2. Description of the Prior Art 
     Current organic light-emitting diode (OLED) panels often suffer from mura and affect their yield. The so-called “mura” refers to various traces caused by non-uniform brightness of the panel. Since the mura generally exists on the background of non-uniform light source, it is impossible for the human eye to effectively distinguish between normal image and mura. As a result, many techniques for correcting mura have emerged. 
     A common demura method at present is to firstly measure the brightness of each sub-pixel of the panel to determine whether each sub-pixel has mura, and then to change the data signal outputted to each sub-pixel of the panel accordingly and then achieve the effect of lightness compensation. 
     However, the severity of mura may be different in different panels. As shown in  FIG. 1 , the severities of a first mura MR 1  and a second mura MR 2  displayed on a first panel PL 1  and a second panel PL 2  respectively are very different. At this time, if the same demura algorithm is used to perform optical compensation on the first panel PL 1  and the second panel PL 2 , it is likely to cause over-compensation or under-compensation and it needs to be overcome. 
     SUMMARY OF THE INVENTION 
     Therefore, the invention provides an optical compensation apparatus applied to a plurality of panels and an operating method thereof to solve the above-mentioned problems of the prior arts. 
     A preferred embodiment of the invention is an optical compensation apparatus. In this embodiment, the optical compensation apparatus is applied to a plurality of panels. A first panel of the plurality of panels includes a plurality of sub-pixels for displaying a display data. The optical compensation apparatus includes an optical measurement module, a data processing module and an optical compensation module. The optical measurement module is used for measuring a plurality of first optical measurement values corresponding to the plurality of sub-pixels of the first panel. The data processing module is coupled to the optical measurement module and used for determining a plurality of first optical compensation values needed for the plurality of sub-pixels according to the first optical measurement values respectively, determining a first overall compensation operation reference of the first panel according to the plurality of first optical compensation values, determining a first demura algorithm suitable for the first panel according to at least one adjustable threshold compensation value and the first overall compensation operation reference and obtaining a plurality of second optical compensation values according to the first demura algorithm. The optical compensation module is coupled to the data processing module and used for outputting the plurality of second optical compensation values to perform optical compensation on the display data provided to the first panel. 
     In an embodiment, the plurality of panels is an organic light-emitting diode (OLED) panel. 
     In an embodiment, the plurality of optical measurement values is lightness values of the plurality of sub-pixels. 
     In an embodiment, the optical measurement module includes a control unit, an optical measuring unit and a data accessing unit. The control unit is used for providing a control signal. The optical measuring unit is coupled to the control unit and used for performing optical measuring on the plurality of sub-pixels of the first panel according to the control signal to obtain the plurality of first optical measurement values. The data accessing unit is coupled to the optical measuring unit and used for accessing the plurality of optical measurement values from the optical measuring unit. 
     In an embodiment, the data processing module includes a data analyzing unit, a data processing unit, an overall compensation operation reference generation unit and a demura algorithm selection unit. The data analyzing unit is coupled to the optical measurement module and used for receiving and analyzing the plurality of first optical measurement values. The data processing unit is coupled to the data analyzing unit and used for determining the first optical compensation values needed for the sub-pixels according to the first optical measurement values respectively. The overall compensation operation reference generation unit is coupled to the data processing unit and used for determining the first overall compensation operation reference of the first panel according to the plurality of first optical compensation values. The demura algorithm selection unit is coupled to the overall compensation operation reference generation unit and used for determining a first demura algorithm suitable for the first panel according to at least one adjustable threshold compensation value and the first overall compensation operation reference and obtaining the plurality of second optical compensation values according to the first demura algorithm. 
     In an embodiment, when the first overall compensation operation reference is smaller than or equal to a first threshold compensation value of the at least one threshold compensation value, the data processing module determines that the first demura algorithm corresponding to the first threshold compensation value is suitable for the first panel. 
     In an embodiment, when the first overall compensation operation reference is smaller than or equal to a first threshold compensation value of the at least one threshold compensation value, the data processing module determines that the first demura algorism corresponding to the first threshold compensation value is suitable for the first panel. 
     In an embodiment, the optical compensation module and the first panel are both coupled to a display driving apparatus, and the display driving apparatus receives the display data and the plurality of second optical compensation values respectively and performs optical compensation on the display data according to the plurality of second optical compensation values and then outputs the optical compensated display data to the first panel. 
     In an embodiment, the data processing module determines the first overall compensation operation reference by summing absolute values of the plurality of first optical compensation values. 
     In an embodiment, the data processing module determines the first overall compensation operation reference by summing a product of absolute values of the plurality of first optical compensation values and a parameter. 
     In an embodiment, when a part of the first optical compensation values has absolute values meeting a specific condition, the data processing module determines the first overall compensation operation reference by summing the absolute values of the part of the first optical compensation values. 
     In an embodiment, when a part of the first optical compensation values has absolute values and a product of the absolute values and a parameter meets a specific condition, the data processing module determines the first overall compensation operation reference by summing the product of the absolute values of the part of the first optical compensation values and the parameter. 
     Another preferred embodiment of the invention is an optical compensation apparatus operating method. In this embodiment, the optical compensation apparatus operating method is used for operating an optical compensation apparatus applied to a plurality of panels, a first panel of the plurality of panels including a plurality of sub-pixels for displaying a display data. The optical compensation apparatus operating method includes steps of: (a) measuring a plurality of first optical measurement values corresponding to the plurality of sub-pixels of the first panel; (b) determining a plurality of first optical compensation values needed for the plurality of sub-pixels according to the plurality of first optical measurement values respectively; (c) determining a first overall compensation operation reference of the first panel according to the plurality of first optical compensation values; (d) determining a first demura algorithm suitable for the first panel according to at least one adjustable threshold compensation value and the first overall compensation operation reference; and (e) obtaining a plurality of second optical compensation values according to the first demura algorithm to perform optical compensation on the display data provided to the first panel. 
     Compared to the prior art, even if the severity of mura varies greatly in different panels, the optical compensation apparatus and the operating method thereof according to the invention can grade the severity of mura exists on all panels at first to obtain the overall compensation operation reference of each panel and use suitable demura algorithm to perform corresponding optical compensation on different panels accordingly; therefore, the over-compensation or under-compensation in the prior art can be avoided to effectively reduce the mura on all panels and achieve the optimized demura effect, and the display quality of the panel can be enhanced to improve the visual enjoyment when users watch the panel. 
     The advantage and spirit of the invention may be understood by the following detailed descriptions together with the appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE APPENDED DRAWINGS 
         FIG. 1  illustrates a schematic diagram of the first mura and the second mura having different seventies appeared on the first panel and the second panel respectively. 
         FIG. 2  illustrates a schematic diagram of an optical compensation apparatus applied to the first panel in a preferred embodiment of the invention. 
         FIG. 3  illustrates an embodiment of the different panels having different overall compensation operation reference curves varied with gray scales respectively. 
         FIG. 4  illustrates a flowchart of an optical compensation apparatus operating method in another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A preferred embodiment of the invention is an optical compensation apparatus. In this embodiment, the optical compensation apparatus is applied to a plurality of panels (e.g., a plurality of OLED panels), but not limited to this. Each of the panels includes a plurality of sub-pixels for displaying a display data. 
     Please refer to  FIG. 2 .  FIG. 2  illustrates a schematic diagram of an optical compensation apparatus  1  applied to a first panel PL 1  of the plurality of panels in this embodiment. As for the case where the optical compensation apparatus  1  is applied to other display panels of the plurality of panels, it can be similarly applied. 
     As shown in  FIG. 2 , the optical compensation apparatus  1  is disposed corresponding to the first panel PL 1 , and the optical compensation apparatus  1  and the first panel PL 1  are both coupled to a display driving apparatus DR. The display driving apparatus DR is used for receiving a display data DAT and outputting the display data DAT to the sub-pixels P 1 ˜Pn of the first panel PL 1  for displaying, wherein n is a positive integer larger than 1. 
     The optical compensation apparatus  1  includes an optical measurement module  12 , a data processing module  14  and an optical compensation module  16 . The data processing module  14  is coupled to the optical measurement module  12 ; the optical compensation module  16  is coupled to the data processing module  14  and the optical compensation module  16  is also coupled to the display driving apparatus DR. 
     The optical measurement module  12  is disposed corresponding to the first panel PL 1  and used for measuring a plurality of first optical measurement values V 1 ˜Vn (e.g., the lightness, but not limited to this) corresponding to the plurality of sub-pixels P 1 ˜Pn of the first panel PL 1  respectively. 
     In this embodiment, the optical measurement module  12  can include a control unit  120 , a data accessing unit  122  and an optical sensing unit  124 . The control unit  120  and the data accessing unit  122  are both coupled to the optical sensing unit  124 . 
     When the control unit  120  provides a control signal CTL to the optical sensing unit  124 , the optical sensing unit  124  will perform optical sensing on the plurality of sub-pixels P 1 ˜Pn of the first panel PL 1  according to the control signal CTL to obtain the plurality of first optical measurement values V 1 ˜Vn corresponding to the plurality of sub-pixels P 1 ˜Pn. 
     Then, the data accessing unit  122  will access the plurality of first optical measurement values V 1 ˜Vn from the optical measuring unit  124  and transmit the plurality of first optical measurement values V 1 ˜Vn to the data processing module  14 . In practical applications, the optical measuring unit  124  can be optical lens or any other device having the optical measuring function, but not limited to this. 
     In this embodiment, the data processing module  14  can include a data analyzing unit  140 , a data processing unit  142 , an overall compensation operation reference generation unit  144  and a demura algorithm selection unit  146 . 
     The data analyzing unit  140  is coupled to the optical measurement module  142  and used for receiving and analyzing the plurality of first optical measurement values V 1 ˜Vn. The data processing unit  142  is coupled to the data analyzing unit  140  and used for determining the first optical compensation values COMP 1  needed for the sub-pixels P 1 ˜Pn according to the first optical measurement values V 1 ˜Vn respectively. 
     The overall compensation operation reference generation unit  144  is coupled to the data processing unit  142  and used for determining the first overall compensation operation reference REF of the first panel PL 1  according to the plurality of first optical compensation values COMP 1 . 
     In practical applications, the overall compensation operation reference generation unit  144  of the data processing module  14  can use different methods to determine the first overall compensation operation reference REF of the first panel PL 1  according to the plurality of first optical compensation values COMP 1  based on practical needs. 
     For example, the overall compensation operation reference generation unit  144  can generate the first overall compensation operation reference REF by summing absolute values of the first optical compensation values COMM; the overall compensation operation reference generation unit  144  can generate the first overall compensation operation reference REF by summing a product of absolute values of the first optical compensation values COMP 1  and a parameter; when a part of the first optical compensation values COMP 1  has absolute values meeting a specific condition (e.g., larger than a specific value, but not limited to this), the overall compensation operation reference generation unit  144  can generate the first overall compensation operation reference REF by summing the absolute values of the part of the first optical compensation values COMP 1 ; when a part of the first optical compensation values COMP 1  has absolute values and a product of the absolute values of the part of the first optical compensation values COMP 1  and a parameter meets a specific condition (e.g., larger than a specific value, but not limited to this), the overall compensation operation reference generation unit  144  can generate the first overall compensation operation reference REF by summing the product of the absolute values of the part of the first optical compensation values COMP 1  and the parameter, but not limited to this. 
     For example, as shown in  FIG. 3 , it is assumed that the optical compensation apparatus  1  is applied to six panels and the overall compensation operation reference curves REF 1 ˜REF 6  of the six panels are varied with gray scales respectively. Since the overall compensation operation reference of each panel can correspond to the severity of the mura on each panel, it can be found that the overall compensation operation reference curve REF 1  is obviously higher than other overall compensation operation reference curves REF 2 ˜REF 6  no matter under what gray scale in  FIG. 3 . It means that the severity of the mura on the first panel PL 1  corresponding to the overall compensation operation reference curve REF 1  is obviously higher than the severity of the mura on the other panels corresponding to the other overall compensation operation reference curves REF 2 ˜REF 6 . 
     The demura algorithm selection unit  146  is coupled to the overall compensation operation reference generation unit  144  and used for determining a first demura algorithm AG 1  suitable for the first panel PL 1  according to at least one adjustable threshold compensation value TH and the first overall compensation operation reference REF, obtaining a plurality of second optical compensation values COMP 2  according to the first demura algorithm AG 1  and then outputting the plurality of second optical compensation values COMP 2  to the optical compensation module  16 . 
     From the above-mentioned example, since the severity of the mura on the first panel PL 1  is obviously higher than the severity of the mura on the other panels, the demura algorithm selection unit  146  will correspondingly select the first demura algorithm AG 1  suitable for the serious mura for the first panel PL 1  to effectively reduce the serious mura on the first panel PL 1 . As for the selection of the demura algorithm of the other display panels, it can be similarly described here without further description. 
     Then, the optical compensation module  16  will output the second optical compensation values COMP 2  to the display driving apparatus DR, and the display driving apparatus DR will perform optical compensation on the display data DAT according to the second optical compensation values COMP 2  to generate an optically compensated display data DAT′. And then, the display driving apparatus DR will output the optically compensated display data DAT′ to the first panel PL 1  for displaying. 
     In practical applications, the demura algorithm selection unit  146  can store the at least one adjustable threshold compensation value TH and N demura algorithms AG 1 ˜AGN, and there can be a specific relationship between the at least one adjustable threshold compensation value TH and the N demura algorithms AG 1 ˜AGN, wherein N is a positive integer larger than 1. 
     It should be noticed that the N demura algorithms AG 1 ˜AGN can include different mura detections, different calculation formulas, different compression methods and different parameters, etc, but not limited to this. 
     For example, when the first overall compensation operation reference REF is smaller than or equal to a first threshold compensation value of the at least one threshold compensation value TH, the demura algorithm selection unit  146  of the data processing module  14  will select the first demura algorithm AG 1  corresponding to the first threshold compensation value from the N demura algorithms AG 1 ˜AGN to be the demura algorithm suitable for the first panel PL 1 , and so on, but not limited to this. 
     Another preferred embodiment of the invention is an optical compensation apparatus operating method. In this embodiment, the optical compensation apparatus operating method is used for operating an optical compensation apparatus applied to a plurality of panels and each panel of the plurality of panels includes a plurality of sub-pixels for displaying a display data. And, the severities of mura are different on different panels. 
     Please refer to  FIG. 4 .  FIG. 4  illustrates a flowchart of the optical compensation apparatus operating method in this embodiment. As shown in  FIG. 4 , taking a first panel of the plurality of panels for example, the optical compensation apparatus operating method includes following steps. 
     Step S 10 : Measuring first optical measurement values corresponding to the sub-pixels of the first panel (e.g., the lightness values of the sub-pixels, but not limited to this). 
     Step S 12 : Determining first optical compensation values needed for the sub-pixels according to the first optical measurement values respectively. 
     Step S 14 : Determining a first overall compensation operation reference of the first panel according to the first optical compensation values. 
     Step S 16 : Determining a first demura algorithm suitable for the first panel according to at least one adjustable threshold compensation value and the first overall compensation operation reference. 
     Step S 18 : Obtaining second optical compensation values according to the first demura algorithm to perform optical compensation on the display data provided to the first panel. 
     Similarly, the above steps can be also applied to each of the other display panels (e.g., the second display panel, the third display panel, etc.) and not be repeated herein. Therefore, the optical compensation apparatus operation method in this embodiment can determine the overall compensation operation reference value of each panel respectively and then determine the appropriate demura algorithm for each panel accordingly to perform different optical compensations on the display data provided to each panel, so that each panel can achieve the optimized demura effect without any occurrence of over-compensation or under-compensation. 
     Compared to the prior art, even if the severity of mura varies greatly in different panels, the optical compensation apparatus and the operating method thereof according to the invention can grade the severity of mura exists on all panels at first to obtain the overall compensation operation reference of each panel and use suitable demura algorithm to perform corresponding optical compensation on different panels accordingly; therefore, the over-compensation or under-compensation in the prior art can be avoided to effectively reduce the mura on all panels and achieve the optimized demura effect, and the display quality of the panel can be enhanced to improve the visual enjoyment when users watch the panel. 
     With the example and explanations above, the features and spirits of the invention will be hopefully well described. Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teaching of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.