AMOLEDEM dimming brightness correction method and device

Abstract

The invention discloses an AMOLED EM dimming segment brightness correction method. When the EM duty is maximum, gamma0 is debugged to obtain the voltage of each binding point grayscale; at different EMduty, the input voltage of each binding point grayscale is corrected according to the theoretical brightness; the grayscale on gamma0 is converted according to the corrected voltage, and the LUT of EMDuty_Gray is established; when the grayscale G of the input gammaK and the EM duty are known, if the EM dimming mode is used, the G on gammaK is converted to obtain the G′ on gamma0; according to the established EMduty_Gray LUT, a table is looked up and interpolation is performed to calculate the G″ corrected corresponding to the G′ on this EMduty; G″ is input to a DGC module to look up the table and calculate to obtain the voltage data of the corresponding grayscale, and the data is finally output; if the EM dimming mode is not used, G is directly input to the DGC module to perform interpolation calculation to obtain the voltage data of the corresponding grayscale, and the data is finally output.

Description

Technical Field

[0001] The invention relates to a panel display method, and in particular to an AMOLEDEM dimming brightness correction method and device. Background Art

[0002] The commonly used dimming methods of AMOLED (Active Matrix Organic Light Emitting Diode) display technology include data dimming, EM dimming and a combination of the two methods. Data dimming is to change the display brightness by modifying the charging voltage in the subpixel circuit and changing the current flowing through the OLED device; EM dimming is based on fixed data, that is, keeping the current unchanged, changing the time (EM duty) of the current passing through the OLED device within one frame time, and adding a high refresh rate to visually change the display brightness.

[0003] Currently, the more popular dimming method is the dimming method of data and EM segment combination (such as Figure 1 ), in an ideal state, the entire brightness curve can be smoothly transitioned with DCS51, and there will be no connection problems when switching from the EM dimming segment to the data dimming segment or switching different gammas in the EM dimming segment.

[0004] However, in actual applications, it is found that as the EM dimming section of DCS51 gradually decreases, the EM duty decreases accordingly, and the brightness curve gradually deviates from the theoretical brightness value, causing problems at the joints of the entire brightness curve (such as Figure 2 The main reason is that OLED light-emitting diodes have a capacitive effect. EMduty controls the time the current flows through the OLED, and data controls the magnitude of the current flowing through (e.g. Figure 3 ). The smaller the current flowing through the OLED light-emitting diode, the longer it takes for the capacitor to be fully charged. When the current is fixed, the charging time is also fixed, and the EMduty gradually decreases, the proportion of charging time in EMduty becomes larger and larger, which is equivalent to EMduty gradually deviating from the theoretical value, thereby affecting the final display brightness. Summary of the invention

[0005] The present invention provides an AMOLEDEM dimming brightness correction method, comprising the following steps:

[0006] Step 1: Debug gamma0 when EM duty is maximum to obtain the grayscale voltage of each binding point;

[0007] Step 2: At different EMduty, correct the input voltage of each binding point grayscale according to the theoretical brightness;

[0008] Step 3, convert the grayscale corresponding to gamma0 according to the corrected voltage and establish the LUT of EMDuty_Gray;

[0009] Step 4: Convert G on gammaK to G′ on gamma0.

[0010] Step 5: In the DGC (Digital Gamma Control) module, a table is looked up to calculate and obtain the voltage data corresponding to the input grayscale.

[0011] Furthermore, in step 1, a gamma correction system is used to debug the target gamma value γ to obtain the voltage corresponding to the grayscale of each binding point on gamma0, and a LUT1 lookup table is established for the three RGB channels:

[0012] LUT1:[G0,G1,G2……,G n, ]=[f(V0),f(V1),f(V2)……,(fV n )]

[0013] Where X=[V0,V1,V2……V n ] represents the voltage corresponding to the grayscale of the binding point on gamma0, Y=[G0,G1,G2……G n ] is the corresponding binding point grayscale. Any input voltage can be linearly interpolated through LUT1 to obtain the corresponding grayscale value.

[0014] Furthermore, the grayscale of the binding point in step 2 includes but is not limited to the grayscale of the binding point of gamma0. k ], according to the target brightness of each binding point grayscale, the corrected binding point grayscale voltage is obtained through the gamma correction system, and the LUT2 lookup table is generated for R, G, and B respectively:

[0015]

[0016] Where X=[E0,E1,E2……E k ] indicates different EM duties; Y=[G0,G1,G2……G n ] indicates binding point grayscale; Indicates the voltage of different EMduty corresponding to the grayscale of each binding point; any input grayscale can be used to obtain the corresponding voltage through bilinear interpolation of LUT2 table lookup.

[0017] Furthermore, the corrected voltage obtained in step 2 is input into LUT1, and the grayscale that should be output after correction at different EMduty for each binding point can be obtained. The lookup table of LUT3 is generated for R, G, and B respectively:

[0018]

[0019] Where X=[E0,E1,E2……E k ] indicates different EM duties; Y=[G0,G1,G2……G n ] indicates binding point grayscale; Indicates that the grayscale of each binding point corresponds to the grayscale after different EMduty compensation; any input grayscale can be obtained by bilinear interpolation through LUT3 table lookup to obtain the corresponding compensated grayscale;

[0020] Bilinear interpolation is used to obtain the output grayscale at different EMduty. The bilinear interpolation formula is as follows:

[0021]

[0022]

[0023]

[0024] Furthermore, dimming involves the switching of multiple gamma groups. LUT3 is based on gamma0. Other gammas need to be converted to gamma0 for table lookup. The specific conversion formula is as follows:

[0025]

[0026] Where L gammaK and L gamma0 is the maximum brightness of gammaK and gamma0; γ is the gamma value, which is consistent with the target gamma value of gamma0 in step 1.

[0027] Furthermore, the DGC module obtains the voltage data corresponding to the input grayscale by reverse table lookup calculation based on LUT1 established in step 1. The reverse table lookup of LUT1 is equivalent to the table lookup calculation of the following LUT1′:

[0028] LUT1′:[V0,V1,V2……,V n ]=[f(G0),f(G1),f(G2)……,f(G n )]

[0029] Where X=[G0,G1,G2……G n ] represents the grayscale of the binding point on gamma0, Y=[V0,V1,V2……V n ] indicates the voltage corresponding to the grayscale of the binding point. Any input grayscale can be linearly interpolated through the LUT1′ table lookup to obtain the corresponding voltage.

[0030] The present invention also provides an AMOLEDEM dimming brightness correction device, comprising:

[0031] Brightness adjustment unit coordinates EM dimming and Data dimming, determines EM duty size and gamma selection;

[0032] Brightness correction unit, which corrects the brightness of the EM dimming segment according to the input R_Gray / G_Gray / B_Gray;

[0033] The DGC unit converts the gray scale obtained after correction by the brightness correction unit into a voltage output. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The figure shows a dimming method example of the prior art data and EM segment combination;

[0035] Figure 2 The figure shows an example of the prior art causing a problem at the joint of the entire brightness curve;

[0036] Figure 3 The figure shows an example of the application of OLED light emitting diode in the prior art;

[0037] Figure 4 Shown is a flow chart of the method implementation of the present invention;

[0038] Figure 5 Shown is the lookup table of LUT2 of the present invention;

[0039] Figure 6 Shown is the lookup table of LUT3 of the present invention;

[0040] Figure 7 Shown is a schematic diagram of bilinear interpolation of the present invention;

[0041] Figure 8 Shown is a schematic structural diagram of the EM dimming brightness correction device of the present invention. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] See also Figure 1-8 The present invention provides an AMOLEDEM dimming brightness correction method (such as Figure 4 ), including the following steps:

[0044] Step 1: Debug gamma0 when EM duty is maximum to obtain the grayscale voltage of each binding point;

[0045] Step 2: At different EMduty, correct the input voltage of each binding point grayscale according to the theoretical brightness;

[0046] Step 3, convert the grayscale corresponding to gamma0 according to the corrected voltage and establish the LUT of EMDuty_Gray;

[0047] Step 4: Convert G on gammaK to G′ on gamma0.

[0048] Step 5: In the DGC (Digital Gamma Control) module, a table is looked up to calculate and obtain the voltage data corresponding to the input grayscale.

[0049] Use the gamma correction system to debug the target gamma value γ to get the voltage corresponding to the grayscale of each binding point on gamma0, and establish the LUT1 lookup table for the three RGB channels:

[0050] LUT1:[G0,G1,G2……,G n, ]=[f(V0),f(V1),f(V2)……,f(V n )]

[0051] Where X=[V0,V1,V2……V n ] represents the voltage corresponding to the grayscale of the binding point on gamma0, Y=[G0,G1,G2……G n ] is the corresponding binding point grayscale. Any input voltage can be linearly interpolated through LUT1 to obtain the corresponding grayscale value.

[0052] The grayscale of the binding point here includes but is not limited to the grayscale of the binding point of gamma0. k ], according to the target brightness of each grayscale of the binding point, the corrected grayscale voltage of the binding point is obtained through the gamma correction system, and the LUT2 lookup table (such as Figure 5 ):

[0053]

[0054] Where X=[E0,E1,E2……E k ] indicates different EM duties; Y=[G0,G1,G2……G n ] indicates binding point grayscale; Indicates the voltage of different EMduty corresponding to the grayscale of each binding point; any input grayscale can be used to obtain the corresponding voltage through bilinear interpolation of LUT2 table lookup.

[0055] Input the corrected voltage obtained in step 2 into LUT1, and you can get the grayscale that should be output after the grayscale of each binding point is corrected at different EMduty. R, G, and B each generate the lookup table of LUT3 (such as Figure 6 ):

[0056]

[0057] Where X=[E0,E1,E2……E k ] indicates different EM duties; Y=[G0,G1,G2……G n ] indicates binding point grayscale; Indicates that the grayscale of each binding point corresponds to the grayscale after different EMduty compensation; any input grayscale can be obtained by bilinear interpolation through LUT3 table lookup to obtain the corresponding compensated grayscale;

[0058] like Figure 7 As shown, bilinear interpolation is used to obtain the output grayscale at different EMduty. The bilinear interpolation formula is as follows:

[0059]

[0060]

[0061]

[0062] Dimming involves the switching of multiple gamma groups. LUT3 is based on gamma0. Other gammas need to be converted to gamma0 for table lookup. The specific conversion formula is as follows:

[0063]

[0064] Where L gammaK and L gamma0 is the maximum brightness of gammaK and gamma0; γ is the gamma value, which is consistent with the target gamma value of gamma0 in step 1.

[0065] In the DGC module, the voltage data corresponding to the input grayscale is calculated by the reverse table lookup of LUT1 established in step 1. The reverse table lookup of LUT1 is equivalent to the table lookup calculation of LUT1′ below:

[0066] LUT1′:[V0,V1,V2……,V n ]=[f(G0),f(G1),f(G2)……,f(G n)]

[0067] Where X=[G0,G1,G2……G n ] represents the grayscale of the binding point on gamma0, Y=[V0,V1,V2……V n ] indicates the voltage corresponding to the grayscale of the binding point. Any input grayscale can be linearly interpolated through the LUT1′ table lookup to obtain the corresponding voltage.

[0068] The present invention also provides an AMOLEDEM dimming brightness correction device (such as Figure 8 ),include:

[0069] Brightness adjustment unit coordinates EM dimming and Data dimming, determines EM duty size and gamma selection;

[0070] Brightness correction unit, which corrects the brightness of the EM dimming segment according to the input R_Gray / G_Gray / B_Gray;

[0071] The DGC unit converts the gray scale obtained after correction by the brightness correction unit into a voltage output.

[0072] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0073] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is limited by the appended claims and their equivalents.

Claims

1. A method for correcting the brightness of an AMOLED EM dimming display, characterized in that: The following steps are involved: Step 1: Debug gamma0 when EM duty is maximum to obtain the grayscale voltage of each binding point; Step 2: At different EMduty, correct the input voltage of each binding point grayscale according to the theoretical brightness; Step 3, convert the grayscale corresponding to gamma0 according to the corrected voltage and establish the LUT of EMDuty_Gray; Step 4: Convert G on gammaK to G′ on gamma0. Step 5, the DGC (Digital Gamma Control) module calculates and obtains the voltage data corresponding to the input grayscale; In step 1, a gamma correction system is used to debug the target gamma value γ to obtain the voltage corresponding to the grayscale of each binding point on gamma0, and a LUT1 lookup table is established for the three RGB channels: LUT1:[G0,G1,G2……,G n, ]=[f(V0),f(V1),f(V2)……,f(V n )] Where X=[V0,V1,V2……V n ] represents the voltage corresponding to the grayscale of the binding point on gamma0, Y=[G0,G1,G2……G n ] is the corresponding grayscale of the binding point. Any input voltage can be linearly interpolated through LUT1 to get the corresponding grayscale value; The grayscale of the binding point in step 2 includes but is not limited to the grayscale of the binding point of gamma0, in different EMduty [E0, E1, E2...E k ], according to the target brightness of each binding point grayscale, the corrected binding point grayscale voltage is obtained through the gamma correction system, and the LUT2 lookup table is generated for R, G, and B respectively: LUT2: Where X=[E0,E1,E2……E k ] indicates different EM duties; Y=[G0,G1,G2……G n ] indicates binding point grayscale; Indicates the voltage of different EMduty corresponding to the grayscale of each binding point; any input grayscale can be obtained by bilinear interpolation through LUT2 table lookup to obtain the corresponding voltage; Input the corrected voltage obtained in step 2 into LUT1, and you can get the grayscale that should be output after the grayscale of each binding point is corrected at different EMduty. R, G, and B each generate the lookup table of LUT3: LUT3: Where X=[E0,E1,E2……E k ] indicates different EM duties; Y=[G0,G1,G2……G n ] indicates binding point grayscale; Indicates that the grayscale of each binding point corresponds to the grayscale after different EMduty compensation; any input grayscale can be obtained by bilinear interpolation through LUT3 table lookup to obtain the corresponding compensated grayscale; Bilinear interpolation is used to obtain the output grayscale at different EMduty. The bilinear interpolation formula is as follows: and as well as Where i, l and j represent any natural numbers, indicating the i, l and jth binding points, m, f and p represent any natural numbers, indicating the m, f and pth grayscales after EMduty compensation corresponding to the grayscale of the binding point, G i , G l , G j , respectively represent the grayscale of the binding point, that is, the grayscale of the i-th, l-th and j-th binding points; dimming involves the mutual switching of multiple groups of gamma, LUT3 is based on gamma0, and other gammas need to be converted to gamma0 for table lookup. The specific conversion formula is as follows: Where L ga,maK and L gamm is the maximum brightness of gammaK and gamma0; γ is the gamma value, which is consistent with the target gamma value of gamma0 in step 1; G is the grayscale G of the input gammaK, and G′ is the grayscale G′ on gamma0.

2. The AMOLEDEM dimming brightness correction method according to claim 1, characterized in that: In the DGC module, the voltage data corresponding to the input grayscale is obtained by reverse table lookup calculation of LUT1 established in step 1. The reverse table lookup of LUT1 is equivalent to the table lookup calculation of LUT1′ below: LUT1′:[V0,V1,V2……,V n ]=[f(G0),f(G1),f(G2)……,f(G n )] Where X=[G0,G1,G2……G n ] represents the grayscale of the binding point on gamma0, Y=[V0,V1,V2……V n ] indicates the voltage corresponding to the grayscale of the binding point. Any input grayscale can be linearly interpolated through the LUT1′ table lookup to obtain the corresponding voltage.

3. An AMOLEDEM dimming brightness correction device, according to any one of the AMOLEDEM dimming brightness correction methods according to claims 1-2, comprising: Brightness adjustment unit coordinates EM dimming and Data dimming, determines EM duty size and gamma selection; Brightness correction unit, which corrects the brightness of the EM dimming segment according to the input R_Gray / G_Gray / B_Gray; The DGC unit converts the gray scale obtained after correction by the brightness correction unit into a voltage output.

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