A Voltage Domain Gamma Interpolation Method for AMOLED Displays

Abstract

The present invention provides a Gamma interpolation method and device based on a voltage domain, including a voltage domain look-up table conversion unit, a voltage domain look-up table mixing unit, a voltage domain output look-up unit, an upper and lower limit voltage mixing unit, and a data domain output conversion unit. The voltage domain Gamma interpolation method proposed by the present invention performs interpolation on a virtual voltage domain with higher precision, which can ensure uniform transition of brightness during the dimming process and simultaneously ensure accurate controllability of the data line output voltage.

Description

Technical Field

[0001] The present invention belongs to the technical field of AMOLED display, and relates to a voltage-domain Gamma interpolation method and device for an AMOLED display screen. Background Art

[0002] The driving chip of an AMOLED display screen adjusts the gray-scale brightness by adjusting the output voltage of the data line corresponding to each gray scale. The output voltages of the data lines for different gray scales can be adjusted through a Gamma mapping table or voltage upper and lower limit settings, where the voltage upper and lower limits determine the maximum and minimum values of the actual voltages corresponding to the output data of the Gamma mapping table.

[0003] Generally speaking, different Gammas can share the same voltage upper and lower limit settings, that is, the output data after querying the Gamma mapping table has a linear relationship with the actual voltage it represents. At this time, if Gamma interpolation is required, it is relatively easy, and interpolation can be directly performed on the data domain represented by the Gamma mapping table according to the interpolation ratio. However, in order to improve the expression accuracy of the output voltage of the data line, different voltage upper and lower limits are also used between different Gammas. At this time, the correspondence between the output data after querying different Gamma mapping tables and the actual voltage is not fixed and also depends on the voltage upper and lower limits used by the Gamma. Therefore, traditional interpolation methods cannot be used to calculate the interpolation result.

[0004] To adapt to the situation where different voltage upper and lower limits are applied to different Gammas, it is necessary to propose a Gamma interpolation method and device based on the voltage domain. Summary of the Invention

[0005] The present invention provides a voltage-domain Gamma interpolation method, including:

[0006] Step 1, calculate the output voltages of each binding point of the high-brightness Gamma and the low-brightness Gamma respectively according to the upper and lower limit voltages of the high-brightness Gamma and the low-brightness Gamma and the output data of each binding point;

[0007] Step 2, calculate the output voltages of each binding point of the current Gamma after mixing according to the output voltages of each binding point of the high-brightness Gamma and the low-brightness Gamma according to the mixing ratio under the current dimming;

[0008] Step 3, search and interpolate to calculate the output voltage of the current point among the output voltages of each binding point of the current Gamma after mixing according to the input data of the current point;

[0009] Step 4, calculate the upper and lower limit voltages of the current Gamma after mixing according to the upper and lower limit voltages of the high-brightness Gamma and the low-brightness Gamma according to the mixing ratio under the current dimming;

[0010] Step 5: Calculate the output data of the current point under the current upper and lower limit voltages based on the output voltage of the current point and the upper and lower limit voltages of the current Gamma after mixing.

[0011] Further, in Step 1, the Gamma lookup table consists of P + 1 binding points from X0 to X P and the lookup table can be expressed by the following formula

[0012] LUT[i] = C[X i , i ∈ [0, P]

[0013] where the output C represents the correspondence between the input data of each binding point and LUT[i], and C[X i can represent different voltages under different voltage upper and lower limits, and any input data between X0 and X P can be obtained by interpolation calculation from LUT[0] to LUT[P];

[0014] The output voltages of each binding point can be expressed as

[0015]

[0016] where C[X i is the output data of each binding point, with a range of [0, 2 M - 1], V max and V min are the upper limit voltage and the lower limit voltage respectively, and V[X i is the output voltage of each binding point.

[0017] Further, in Step 2,

[0018] Assume that the mixing ratio under the current dimming is Ratio, with a range of 0 to 1. Then the output voltages of each binding point of the current Gamma after mixing can be expressed as

[0019] V B [X i = V H [X i * Ratio + V L [X i * (1 - Ratio), i ∈ [0, P]

[0020] where V H [X i is the output voltage of each binding point of the high - brightness Gamma, V L [X i is the output voltage of each binding point of the low - brightness Gamma, and V B [X i is the output voltage of each binding point of the current Gamma after mixing.

[0021] Further, in step three,

[0022] For any N-bit gray scale x, if adjacent binding points X that satisfy the following conditions can be found i and X i+1

[0023] X i ≤x≤X i+1

[0024] then the output voltage of the gray scale x can be obtained by interpolating the output voltages of the adjacent binding points

[0025]

[0026] Further, in step four,

[0027] Assume that the upper and lower limit voltages of the high-brightness Gamma are: upper limit voltage V H_max , lower limit voltage V H_min , and the upper and lower limit voltages of the low-brightness Gamma are: upper limit voltage V L_max , lower limit voltage V L_min , then the upper and lower limit voltages of the current Gamma after mixing can be respectively expressed as:

[0028] Upper limit voltage V B_max =V H_max *Ratio + V L_max *(1 - Ratio)

[0029] Lower limit voltage V B_min =V H_min *Ratio + V L_min *(1 - Ratio).

[0030] Further, in step five,

[0031] Assume that the output voltage of the current point on the Gamma after mixing is V B [x], and the upper and lower limit voltages of the Gamma after mixing are V B_max , V B_min , then the output data of the current point on the Gamma after mixing is:

[0032]

[0033] The present invention also provides a device for a Gamma interpolation method based on a voltage domain, including,

[0034] A voltage domain look-up table conversion unit: reads two adjacent Gamma look-up tables, and respectively converts them into two voltage domain Gamma look-up tables according to their respective upper and lower limit voltages, and sends them to the voltage domain look-up table mixing unit;

[0035] Voltage domain lookup table mixing unit: According to the mixing ratio Ratio under the current dimming, mix the two received voltage domain Gamma lookup tables according to this ratio Ratio to obtain the mixed voltage domain Gamma lookup table, and send it to the voltage domain output lookup unit;

[0036] Voltage domain output lookup unit: According to the input data, look up and calculate the corresponding output voltage on the mixed voltage domain Gamma lookup table, and send it to the data domain output conversion unit;

[0037] Upper and lower limit voltage mixing unit: According to the upper and lower limit voltages of two adjacent Gammas and the mixing ratio Ratio, calculate the mixed upper and lower limit voltages and output them, and at the same time send them to the data domain output conversion unit;

[0038] Data domain output conversion unit: Use the output voltage of the voltage domain output lookup unit and the mixed upper and lower limit voltages of the upper and lower limit voltage mixing unit to calculate the output data under the mixed upper and lower limit voltages.

[0039] The voltage domain Gamma interpolation method proposed by the present invention can ensure the uniform transition of brightness during the dimming process and ensure the accurate controllability of the output voltage of the data line by performing interpolation on a virtual voltage domain with higher precision. Description of the Drawings

[0040] Figure 1 Shown is the flowchart of the Gamma interpolation method of the present invention;

[0041] Figure 2 Shown is the Gamma lookup table of the present invention;

[0042] Figure 3 Shown is the structural schematic diagram of the voltage domain Gamma interpolation device of the AMOLED display screen of the present invention. Detailed Embodiments

[0043] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0044] Embodiment 1

[0045] Please refer to the appendix Figure 1 , the present invention provides a Gamma interpolation method based on a voltage domain, including:

[0046] Step 1: Calculate the output voltages of each binding point for high-brightness Gamma and low-brightness Gamma respectively according to the upper and lower limit voltages of high-brightness Gamma and low-brightness Gamma and the output data of each binding point.

[0047] Step 2: Calculate the output voltages of each binding point of the current Gamma after mixing according to the output voltages of each binding point of high-brightness Gamma and low-brightness Gamma and the mixing ratio under the current dimming.

[0048] Step 3: Search and interpolate to calculate the output voltage of the current point among the output voltages of each binding point of the current Gamma after mixing according to the input data of the current point.

[0049] Step 4: Calculate the upper and lower limit voltages of the current Gamma after mixing according to the upper and lower limit voltages of high-brightness Gamma and low-brightness Gamma and the mixing ratio under the current dimming.

[0050] Step 5: Calculate the output data of the current point under the current upper and lower limit voltages according to the output voltage of the current point and the upper and lower limit voltages of the current Gamma after mixing.

[0051] Example 2

[0052] Please refer to Appendix Figure 2 , the Gamma lookup table consists of a total of P + 1 binding points from X0 to X P The lookup table can be expressed by the following formula

[0053] LUT[i] = C[X i , i ∈ [0, P]

[0054] Among them, the output C represents the correspondence between the input data of each binding point and LUT[i]. C[X i can represent different voltages under different voltage upper and lower limits. Any input data between X0 and X P can be obtained by interpolation calculation from LUT[0] to LUT[P];

[0055] The output voltage of each binding point can be expressed as

[0056]

[0057] Among them, C[X i is the output data of each binding point, with a range of [0, 2 M - 1]. V max and V min are the upper limit voltage and the lower limit voltage respectively. V[X i is the output voltage of each binding point.

[0058] Example 3

[0059] Assume that the mixing ratio under the current dimming is Ratio, with a range of 0 to 1. Then the output voltage of each binding point of the current Gamma after mixing can be expressed as

[0060] V B [X i = V H [X i * Ratio + V L [X i * (1 - Ratio), i ∈ [0, P]

[0061] Among them, V H [X i is the output voltage of each binding point of the high - brightness Gamma, V L [X i is the output voltage of each binding point of the low - brightness Gamma, and V B [X i is the output voltage of each binding point of the current Gamma after mixing.

[0062] For any N - bit gray - scale x, if adjacent binding points X i and X i+1

[0063] X i ≤ x ≤ X i+1

[0064] can be found, then the output voltage of the gray - scale x can be obtained by interpolation using the output voltages of the adjacent binding points

[0065]

[0066] Example 4

[0067] Assume that the upper and lower limit voltages of the high - brightness Gamma are: upper limit voltage V H_max , lower limit voltage V H_min , and the upper and lower limit voltages of the low - brightness Gamma are: upper limit voltage V L_max , lower limit voltage V L_min . Then the upper and lower limit voltages of the current Gamma after mixing can be expressed as:

[0068] Upper limit voltage V B_max = V H_max * Ratio + V L_max * (1 - Ratio)

[0069] Lower limit voltage V B_min = V H_min * Ratio + V L_min * (1 - Ratio).

[0070] Example 5

[0071] Assume that the output voltage of the current point on the mixed Gamma is V B [x], and the upper and lower limit voltages of the mixed Gamma are V B_max , V B_min , then the output data of the current point on the mixed Gamma is:

[0072]

[0073] Embodiment 6

[0074] Please refer to the appendix Figure 3 , the present invention also provides a device for a Gamma interpolation method based on a voltage domain, including,

[0075] Voltage domain lookup table conversion unit: Read two adjacent groups of Gamma lookup tables, and respectively convert them into two groups of voltage domain Gamma lookup tables according to their respective upper and lower limit voltages, and send them to the voltage domain lookup table mixing unit;

[0076] Voltage domain lookup table mixing unit: According to the mixing ratio Ratio under the current dimming, mix the two received voltage domain Gamma lookup tables according to this ratio Ratio to obtain a mixed voltage domain Gamma lookup table, and send it to the voltage domain output lookup unit;

[0077] Voltage domain output lookup unit: According to the input data, look up and calculate the corresponding output voltage on the mixed voltage domain Gamma lookup table, and send it to the data domain output conversion unit;

[0078] Upper and lower limit voltage mixing unit: According to the upper and lower limit voltages of two adjacent groups of Gamma, and the mixing ratio Ratio, calculate and output the mixed upper and lower limit voltages, and send them to the data domain output conversion unit at the same time;

[0079] Data domain output conversion unit: Use the output voltage of the voltage domain output lookup unit, and the mixed upper and lower limit voltages of the upper and lower limit voltage mixing unit, to calculate the output data under the mixed upper and lower limit voltages.

[0080] It should be noted that in this text, noun terms such as "high-brightness Gamma" and "low-brightness Gamma", "upper limit voltage" and "lower limit voltage" are only used to distinguish one entity from another, which is a relative concept, and do not necessarily require or imply any actual numerical value or order between these entities. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0081] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is limited by the appended claims and their equivalents.

Claims

1. A Gamma interpolation method based on a voltage domain, characterized in that Including: Step 1: Calculate the output voltages of each binding point of the high-brightness Gamma and the low-brightness Gamma respectively according to the upper and lower limit voltages of the high-brightness Gamma and the low-brightness Gamma and the output data of each binding point. Step 2: Calculate the output voltages of each binding point of the current Gamma after mixing according to the output voltages of each binding point of the high-brightness Gamma and the low-brightness Gamma and the mixing ratio under the current dimming. Step 3: Search and interpolate to calculate the output voltage of the current point among the output voltages of each binding point of the current Gamma after mixing according to the input data of the current point. Step 4: Calculate the upper and lower limit voltages of the current Gamma after mixing according to the upper and lower limit voltages of the high-brightness Gamma and the low-brightness Gamma and the mixing ratio under the current dimming. Step 5: Calculate the output data of the current point under the current upper and lower limit voltages according to the output voltage of the current point and the upper and lower limit voltages of the current Gamma after mixing. The Gamma lookup table consists of P+1 binding points from X0 to X P and is represented by the following formula LUT[i] = C[X i , i ∈ [0, P] Among them, the output C represents the correspondence between the input data of each binding point and LUT[i]. C[X i represents different voltages under different voltage upper and lower limits. Any input data between X0 and X P is obtained by interpolation calculation of LUT[0] to LUT[P]; The output voltage of each binding point is expressed as Among them, C[X i is the output data of each binding point, with a range of [0, 2 M -1], V max and V min are the upper limit voltage and the lower limit voltage respectively, and V[X i is the output voltage of each binding point; In the said Step 2, Assume that the mixing ratio under the current dimming is Ratio, and the range is 0 to 1. Then the output voltage of each binding point of the current Gamma after mixing is expressed as V B [X i = V H [X i * Ratio + V L [X i * (1 - Ratio), i ∈ [0, P] Among them, V H [X i is the output voltage of each binding point of the high-brightness Gamma, V L [X i is the output voltage of each binding point of the low-brightness Gamma, V B [X i is the output voltage of each binding point of the current Gamma after mixing; In the said Step 3, For any N-bit grayscale x, if adjacent tied points X that satisfy the following conditions can be found i and X i+1 X i ≤x≤X i+1 then the output voltage of the gray level x is obtained by interpolation using the output voltages of adjacent binding points Where V B [x] is the output voltage of gray scale x, V B [X i and V B [X i+1 are the output voltages of adjacent bonding pads X i and X i+1 respectively, In the said Step 4, Assume that the upper and lower limit voltages of the high-brightness Gamma are: upper limit voltage V H_max , lower limit voltage V H_min , and the upper and lower limit voltages of the low-brightness Gamma are: upper limit voltage V L_max , lower limit voltage V L_min . Then the upper and lower limit voltages of the current Gamma after mixing are respectively expressed as: Upper limit voltage V B_max = V H_max *Ratio + V L_max *(1 - Ratio) Lower limit voltage V B_min = V H_min *Ratio + V L_min *(1 - Ratio); In the said Step 5 Assume that the output voltage of the current point on the mixed Gamma is V B [x], and the upper and lower limit voltages of the mixed Gamma are V B_max , V B_min , then the output data of the current point on the mixed Gamma is as follows:

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