Display device and its correction method

Abstract

A display device (120) includes a display panel (150), a backlight module (140) and a circuit (130). The display panel (150) includes a plurality of regions (151-153). The backlight module (140) includes a plurality of light emitting units (141-142), each region corresponding to at least one light emitting unit (141-142). The circuit (130) includes at least one correction lookup table corresponding to a first light emitting unit, the correction lookup table recording a parameter and a plurality of duty cycles. The circuit (130) accesses the correction lookup table and determines an output duty cycle according to the duty cycle. The circuit (130) determines a current value of the first light emitting unit according to the output duty cycle and the parameter to drive the first light emitting unit.

Description

Technical Field

[0001] This disclosure relates to a method for calibrating the light-emitting unit within the backlight module of a display device. Background Technology

[0002] Liquid crystal display (LCD) devices include a liquid crystal display panel and a backlight module. Generally, the backlight module includes multiple light-emitting diodes (LEDs) to provide the light source. The brightness of an LED is determined by the current flowing through it. In some conventional techniques, a maximum current is first set, and then the current is adjusted by changing the duty cycle, thereby adjusting the brightness. However, due to factors such as process variations, even using the same current to drive different LEDs may result in different brightness levels. Therefore, how to calibrate the LEDs to provide the desired brightness is a concern for those skilled in the art. Summary of the Invention

[0003] Embodiments of this disclosure provide a display device including a display panel, a backlight module, and circuitry. The display panel includes multiple regions. The backlight module includes multiple light-emitting units, with each region corresponding to at least one light-emitting unit. The circuitry includes at least one calibration lookup table, which corresponds to a first light-emitting unit, and records parameters and multiple duty cycles. The circuitry accesses the calibration lookup table to obtain the duty cycle and determines an output duty cycle based on the duty cycle. The circuitry determines the current value of the first light-emitting unit based on the output duty cycle and the parameters to drive the first light-emitting unit.

[0004] In some implementations, the circuit drives the first light-emitting unit to generate multiple corresponding luminances based on the duty cycle and parameters. The duty cycle and luminance define the luminance-duty cycle response curve, which is a piecewise linear function composed of multiple linear functions.

[0005] In some embodiments, each linear function has a slope and a corresponding set of duty cycles. The duty cycles corresponding to the linear function include a first set of duty cycles and a second set of duty cycles, where the minimum value of the first set of duty cycles is equal to the maximum value of the second set of duty cycles. The slope of the linear function corresponding to the first set of duty cycles is greater than the slope of the linear function corresponding to the second set of duty cycles.

[0006] In some embodiments, each linear function has a slope and a corresponding set of duty cycles. The duty cycles corresponding to the linear function include a first set of duty cycles and a second set of duty cycles, where the minimum value of the first set of duty cycles is equal to the maximum value of the second set of duty cycles. The slope of the linear function corresponding to the first set of duty cycles is less than the slope of the linear function corresponding to the second set of duty cycles.

[0007] In some embodiments, the circuit obtains a set value, and the piecewise linear function has at least one inflection point, the inflection point including the duty cycle and the corresponding inflection point brightness. The circuit is used to interpolate the output duty cycle based on the set value and the duty cycle.

[0008] In some embodiments, the circuit calculates the output duty cycle according to the following mathematical formula.

[0009]

[0010] D k Indicates the output duty cycle, B k This represents the luminance of the set value, where i represents the i-th inflection point, and the i-th inflection point contains the luminance B of the inflection point. i and duty cycle D i The (i+1)th inflection point contains the inflection point luminance B. i+1 and duty cycle D i+1 luminance B k Brightness B greater than the inflection point i And less than the inflection point luminance B i+1 .

[0011] In some embodiments, the circuit drives the first light-emitting unit to generate a corresponding luminance based on the duty cycle and parameters. The duty cycle and luminance define a luminance-duty cycle response curve, which is a linear function.

[0012] In some embodiments, the circuit obtains a set value and uses it to interpolate the output duty cycle based on a linear function and the set value.

[0013] In some embodiments, the circuit is used to calculate the output duty cycle according to the following mathematical formula.

[0014]

[0015] D k This indicates the output duty cycle, m represents the maximum dimming level, n represents the minimum dimming level, k represents the dimming level corresponding to the set value, and D... m D represents the duty cycle corresponding to the maximum dimming level. n This indicates the duty cycle corresponding to the lowest dimming level.

[0016] In some embodiments, the circuit is used to calculate the output duty cycle according to the following mathematical formula.

[0017]

[0018] D k This indicates the output duty cycle, m represents the maximum luminance, n represents the minimum luminance, k represents the luminance corresponding to the set value, and D...m D represents the duty cycle corresponding to maximum luminance. n This indicates the duty cycle corresponding to the lowest luminance.

[0019] In some embodiments, the circuit executes a local dimming algorithm to calculate a set value corresponding to the first light-emitting unit.

[0020] From another perspective, embodiments of this disclosure propose a correction method applicable to a display device. This display device includes a display panel, a backlight module, and circuitry. The display panel includes multiple regions, and the backlight module includes multiple light-emitting units, with each region corresponding to at least one light-emitting unit. The correction method includes: driving a first light-emitting unit to generate a current according to parameters and a first duty cycle, and measuring the first light-emitting unit to obtain a first luminance of the first light-emitting unit; determining whether the first luminance of the first light-emitting unit is less than a preset luminance; if the first luminance is less than the preset luminance, adjusting the parameters so that the first luminance of the first light-emitting unit conforms to a preset luminance, and recording the adjusted parameters in a first correction lookup table corresponding to the first light-emitting unit, and defining a luminance-duty cycle response curve with the preset luminance, the adjusted parameters, and the first duty cycle; and determining whether the luminance-duty cycle response curve of the first light-emitting unit is linear or nonlinear; if the luminance-duty cycle response curve is linear, the circuit obtains the corresponding and adjusted duty cycle according to the luminance on the luminance-duty cycle response curve; if the luminance-duty cycle response curve is nonlinear, the luminance-duty cycle response curve has at least one inflection point, the inflection point including an inflection point luminance and an inflection point duty cycle, and the circuit interpolates the corresponding and adjusted duty cycle according to the inflection point luminance and the inflection point duty cycle.

[0021] In some embodiments, the step of determining whether the luminance-duty cycle response curve of the first light-emitting unit is linear or nonlinear includes: setting multiple candidate duty cycles, driving the first light-emitting unit according to the candidate duty cycles and obtaining the corresponding multiple candidate luminances; calculating multiple slopes of the luminance-duty cycle response curve according to the candidate duty cycles and candidate luminances; and determining that the luminance-duty cycle response curve is nonlinear if the difference between the maximum slope and the minimum slope among these slopes is greater than a critical value.

[0022] In some embodiments, the candidate duty cycle mentioned above includes the initial duty cycle, and the correction method further includes: selecting one of the candidate duty cycles from smallest to largest, calculating the corresponding slope based on the selected candidate duty cycle and the initial duty cycle to update the maximum slope and the minimum slope; and if the difference between the maximum slope and the minimum slope is greater than a critical value, setting the currently selected candidate duty cycle and the corresponding candidate luminance as a new inflection point.

[0023] In some embodiments, the calibration method further includes: when the first luminance obtained by measuring the first light-emitting unit is greater than or equal to the preset luminance, the parameter adjustment step is not performed, the parameter is directly recorded in the first calibration lookup table corresponding to the first light-emitting unit, and a luminance-duty cycle response curve is defined with the preset luminance, the parameter and the first duty cycle.

[0024] In some embodiments, the circuit drives the first light-emitting unit to generate multiple candidate luminances based on multiple candidate duty cycles and parameters. The candidate duty cycles and candidate luminances define the luminance-duty cycle response curve, which is a piecewise linear function composed of multiple linear functions.

[0025] In some embodiments, each linear function has a slope and a corresponding set of duty cycles. The linear function corresponds at least to a first set of duty cycles and a second set of duty cycles, where the minimum value of the first set of duty cycles is equal to the maximum value of the second set of duty cycles. The slope of the linear function corresponding to the first set of duty cycles is greater than the slope of the linear function corresponding to the second set of duty cycles.

[0026] In some embodiments, each linear function has a slope and a corresponding set of duty cycles. The duty cycles corresponding to the linear function include a first set of duty cycles and a second set of duty cycles, where the minimum value of the first set of duty cycles is equal to the maximum value of the second set of duty cycles. The slope of the linear function corresponding to the first set of duty cycles is less than the slope of the linear function corresponding to the second set of duty cycles.

[0027] In some embodiments, the circuit drives the first light-emitting unit to generate a corresponding candidate luminance based on the candidate duty cycle and parameters. The candidate duty cycle and the candidate luminance define the luminance-duty cycle response curve, which is a linear function.

[0028] In some embodiments, the correction method further includes: driving the second light-emitting unit according to parameters and measuring the second luminance of the second light-emitting unit; adjusting the parameters so that the second luminance of the second light-emitting unit conforms to a preset luminance, and recording the adjusted parameters in a second correction lookup table corresponding to the second light-emitting unit; and if there is a turning point in the first correction lookup table, adding the turning point to the second correction lookup table.

[0029] To make the above features and advantages of the present invention more apparent and understandable, embodiments are provided below, and detailed descriptions are given in conjunction with the accompanying drawings. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a current correction system according to one embodiment.

[0031] Figure 2This is a schematic diagram illustrating multiple areas on a display panel and their corresponding light-emitting units according to one embodiment.

[0032] Figure 3 The luminance-duty cycle response curve of the light-emitting unit is plotted according to one embodiment.

[0033] Figure 4 This is a schematic diagram illustrating the search for the inflection point on the luminance-duty cycle response curve, based on one embodiment.

[0034] Figure 5 The luminance-duty cycle response curve of the light-emitting unit is plotted according to one embodiment.

[0035] Figure 6 The luminance-duty cycle response curve of the light-emitting unit is plotted according to one embodiment.

[0036] Figure 7 This is a schematic diagram illustrating the interpolation output duty cycle according to one embodiment.

[0037] Figure 8 This is a flowchart illustrating a calibration method for a display device according to one embodiment. Detailed Implementation

[0038] The terms "first" and "second" used in this article do not specifically refer to order or sequence; they are used only to distinguish components or operations described using the same technical terms.

[0039] Figure 1 This is a schematic diagram illustrating a current correction system according to one embodiment. Please refer to... Figure 1 The current correction system 100 includes an electronic terminal 110 and a display device 120. The electronic terminal 110 can be a personal computer, a server, or various electronic devices with computing capabilities. The display device 120 includes a circuit 130, a backlight module 140, and a display panel 150. The circuit 130 includes a timing controller 131 and a microcontroller 132. The microcontroller 132 can also be replaced with a programmable gate array (FPGA), so it should not be limited to the microcontroller 132 disclosed in this embodiment. The backlight module 140 includes multiple light-emitting units, such as light-emitting diodes (LEDs), which are driven by the current of the backlight module 140 to provide a backlight source. The display panel 150 is, for example, a liquid crystal display panel. Figure 2 This is a schematic diagram illustrating multiple areas on a display panel and their corresponding light-emitting units according to one embodiment. Please refer to... Figure 1 and Figure 2 ,exist Figure 2In this embodiment, the display panel 150 includes 15 regions (e.g., regions 151-153), each region corresponding to multiple light-emitting units (e.g., light-emitting units 141-142). Here, the brightness of each light-emitting unit can be controlled by providing different amounts of current to increase screen contrast. For example, when the image to be displayed in a certain region is darker, the brightness of the corresponding light-emitting unit can be reduced; conversely, when the image to be displayed in a certain region is brighter, the brightness of the corresponding light-emitting unit can be increased. When displaying an image, the timing controller 131 calculates a setting value for each region on the display panel 150, which indicates the required backlight brightness. In some embodiments, each light-emitting unit is controlled by a switch (not shown). When the switch is on, current flows through the light-emitting unit; when the switch is off, current does not flow through the light-emitting unit. By controlling the duty cycle of this switch, the magnitude of the current flowing through the light-emitting unit can be effectively determined. Furthermore, Figure 2 This is merely an example; this disclosure does not limit the number of areas the display panel 150 may contain, nor does it limit how many light-emitting units each area may correspond to.

[0040] Please refer to Figure 1 The microcontroller 132 includes multiple calibration lookup tables, each corresponding to a light-emitting unit. Each lookup table records at least one parameter and multiple duty cycles, such as current values ​​or other parameters used to control current values, like amplitude modulation. Based on this parameter and the duty cycle, the magnitude of the current flowing through a light-emitting unit can be determined, thereby determining the brightness of the light-emitting unit. In this embodiment, the current value (mA) of the light-emitting unit is obtained by multiplying the amplitude modulation (mA) by the duty cycle (%). The following explains how this parameter and duty cycle are determined.

[0041] Figure 3 The luminance-duty cycle response curve of the light-emitting unit is shown in one embodiment. Please refer to [reference needed]. Figure 3 The straight line 310 represents the linear relationship between luminance and duty cycle, and the maximum duty cycle D. t Corresponding to luminance B t This maximum duty cycle D t For example, 100%, while luminance B t This is the default (e.g., as specified in product specifications). Curve 320 represents the actual response curve of the light-emitting unit when using the parameter (representing the current value) A. t and maximum duty cycle D t When driving a light-emitting unit, this light-emitting unit only provides a luminance of B. n Among them, luminance B n Less than the preset brightness B tTherefore, the luminance corresponding to the maximum duty cycle must be corrected first.

[0042] Specifically, electronic terminal 110 can, according to parameter A t and duty cycle D t When driving the light-emitting unit, the luminance B on the light-emitting unit is measured using a luminance meter or other suitable measuring element. n And determine the luminance B n Is it less than the preset brightness B? t If the luminance B n Less than the preset brightness B t Then adjust parameter A t So that according to the adjusted parameter A t When driving the light-emitting unit, the brightness of the light-emitting unit conforms to the default brightness B. t (Within a preset error range). The adjusted parameter is represented as A. n_cal This parameter A n_cal This will be recorded in the correction lookup table. In some embodiments, it can also be based on parameter A. t And brightness B n Calculate the corrected parameter A n_cal As shown in the following mathematical formula 1.

[0043] [Mathematical Expression 1]

[0044]

[0045] Next, according to the preset luminance B t Adjusted parameter A n_cal and duty cycle D t A luminance-duty cycle response curve 330 can be defined. The luminance-duty cycle response curve 330 can be plotted by measuring the luminance (also known as candidate luminance) at multiple duty cycles (also known as candidate duty cycles). The more luminances measured, the more accurate the luminance-duty cycle response curve 330 will be. Figure 4 This is a schematic diagram illustrating the search for the inflection point on the luminance-duty cycle response curve, based on one embodiment. Please refer to... Figure 4 First, multiple candidate duty cycles D1 to D7 can be set. Based on these candidate duty cycles D1 to D7, the light-emitting units can be driven to obtain the corresponding multiple candidate luminance B. 1～B7Each candidate duty cycle and its corresponding candidate luminance, represented by coordinates (D1, B1), is a point on the luminance-duty cycle response curve 330. These coordinates determine whether the luminance-duty cycle response curve 330 is linear or non-linear. Specifically, multiple segments 401-408 can be defined based on the candidate duty cycles D1-D7 and candidate luminances B1-B7. For example, the coordinate points (D1, B1) and (D2, B2) define segment 402, and so on. The slope of each segment 401-408 can then be calculated. For instance, the slope of segment 402 is shown in Equation 2 below, and the slopes of other segments can be calculated similarly.

[0046] [Mathematical Expression 2]

[0047]

[0048] If the difference between the maximum and minimum slopes among the slopes of these segments 401–408 is greater than a critical value, then the luminance-duty cycle response curve 330 can be determined to be nonlinear; otherwise, it is linear.

[0049] In some embodiments, the inflection point can also be calculated. Specifically, the initial duty cycle is set to 0, and the corresponding luminance is also 0. The coordinate point (0, 0) is the endpoint of the luminance-duty cycle response curve 330. Next, the maximum and minimum slopes are initialized, for example, the maximum slope is set to 0, and the minimum slope is set to a very large value. Then, candidate duty cycles D1 to D7 are selected from smallest to largest. The corresponding slopes are calculated based on the selected candidate duty cycles and the initial duty cycle, and the maximum and minimum slopes are updated. For example, the first selected duty cycle is D1, with a corresponding slope of B1 / D1. If this slope is less than the minimum slope, the minimum slope is set to B1 / D1; if this slope is greater than the maximum slope, the maximum slope is set to B1 / D1. Next, candidate duty cycle D2 is selected, with a corresponding slope of B2 / D2. If this slope is less than the minimum slope, the minimum slope is set to B2 / D2; if this slope is greater than the maximum slope, the maximum slope is set to B2 / D2. Next, determine if the difference between the maximum and minimum slopes is greater than the aforementioned critical value. If so, set the currently selected candidate duty cycle D2 and its corresponding candidate luminance B2 as a new inflection point, i.e., the coordinate point (D2, B2). After finding a new inflection point, reset the maximum and minimum duty cycles. Then, set the new inflection point (D2, B2) as the new initial endpoint, select a candidate duty cycle D3, calculate the corresponding slope (B3-B2) / (D3-D2), and update the maximum and minimum duty cycles. Repeat this process for all candidate duty cycles.

[0050] If no inflection point is found, it indicates that the luminance-duty cycle response curve 330 is a linear function. If an inflection point is found, each inflection point indicates that the luminance-duty cycle response curve 330 is cut into a new linear segment (linear function). In other words, the luminance-duty cycle response curve 330 is a piecewise linear function composed of (or approximating) multiple linear functions, defined by candidate duty cycles and candidate luminance. From another perspective, each linear function has a slope and a corresponding set of duty cycles. For example, the linear function of segment 402 has a corresponding slope and a set of duty cycles D1 and D2. The slopes of the linear functions for any two sets of duty cycles will be different. For example, duty cycles D5 and D6 are called the first group of duty cycles, while duty cycles D3 and D4 are called the second group of duty cycles. The minimum value D5 in the first group of duty cycles is greater than the maximum value D4 in the second group of duty cycles. The slope of the linear function (segment 406) corresponding to the first group of duty cycles is greater than the slope of the linear function (segment 404) corresponding to the second group of duty cycles. As another example, duty cycles D5 and D6 are called the first group of duty cycles, while duty cycles D4 and D5 are called the second group of duty cycles. The minimum value D5 in the first group of duty cycles is equal to the maximum value D5 in the second group of duty cycles. The slope of the linear function (segment 406) corresponding to the first group of duty cycles is greater than the slope of the linear function (segment 405) corresponding to the second group of duty cycles. Figure 4 In the embodiment, the slope of the linear function gradually increases. That is, the slope of the linear function increases with increasing input brightness. This method allows for finer adjustments when the duty cycle corresponding to the backlight module 140 at low brightness has more increments (brightness B1-B5 corresponding to D1-D5 is below 50% of maximum brightness), and more drastic adjustments when the duty cycle corresponding to the backlight module 140 at high brightness has fewer increments (brightness B6 and B7 corresponding to D6 and D7 are above 50% of maximum brightness). This is beneficial for fine-tuning brightness when the image is dark. However, depending on the characteristics of the light-emitting unit, the slope of the linear function can also gradually decrease. For example, please refer to... Figure 5The luminance-duty cycle response curve 510 is also a piecewise linear function, composed (or approximately) of the linear functions corresponding to segments 501 to 505, with the slopes of these segments decreasing. For example, duty cycles D3 and D4 are called the first group of duty cycles, and duty cycles D1 and D2 are called the second group of duty cycles. The minimum value of the first group of duty cycles, D3, is greater than the maximum value of the second group of duty cycles, D2. The slope of the linear function corresponding to the first group of duty cycles (segment 504) is less than the slope of the linear function corresponding to the second group of duty cycles (segment 502). Again, for example, duty cycles D3 and D4 are called the first group of duty cycles, and duty cycles D2 and D3 are called the second group of duty cycles. The minimum value of the first group of duty cycles, D3, is equal to the maximum value of the second group of duty cycles, D3. The slope of the linear function corresponding to the first group of duty cycles (segment 504) is less than the slope of the linear function corresponding to the second group of duty cycles (segment 503). In other words, the slope of the linear function decreases as the input brightness increases. This method allows for finer adjustments when the backlight module 140 has a larger duty cycle scale (B2, B3, and B4 corresponding to D2, D3, and D4 are higher than 50% of the maximum brightness) at high brightness, and more drastic adjustments when the backlight module 140 has a smaller duty cycle scale scale (B1 corresponding to D1 is lower than 50% of the maximum brightness). This is beneficial for fine-tuning brightness when the ambient brightness is high (e.g., insufficient screen brightness in sunlight or backlight conditions).

[0051] exist Figure 3 In the embodiment, based on the duty cycle D t With preset parameter A t The measured luminance B n Less than the preset brightness B t Therefore, the updated parameters need to be recorded in the calibration lookup table. In some embodiments, if the measured luminance is greater than or equal to the preset luminance, no parameter adjustment is needed, and the default parameters can be directly recorded in the calibration lookup table. For example, Figure 6 This is a schematic diagram illustrating the luminance-duty cycle response curve 510 according to one embodiment. Figure 6 In one embodiment, according to the preset parameter A t and duty cycle D t After driving the LED, the measured luminance is B. n This brightness B n The luminance is greater than the preset luminance Bt, therefore parameter A does not need to be adjusted. t Parameter A can be t Record this in the corresponding correction lookup table. Next, based on the preset luminance B... t Parameter A t and duty cycle D mTo define the luminance-duty cycle response curve 610, where the duty cycle D m This means that this light-emitting unit provides a default brightness of B. t Duty cycle at that time. When providing preset luminance B... t At that time, the preset parameter A can be used. t and duty cycle D m To drive the LED, if you want to provide lower brightness, you just need to reduce the duty cycle.

[0052] According to the above method, the calibration lookup table records the adjusted or unadjusted parameters and multiple duty cycles. An example of the calibration lookup table is shown in Table 1 below.

[0053]

[0054]

[0055] Table 1

[0056] Table 1 corresponds to the nth light-emitting unit. The first column records the dimming level, and in some embodiments, the luminance can also be recorded. The second column records the parameters; in this example, it records the adjusted parameter A. n_cal The third column records the corresponding duty cycle. If the corresponding brightness-duty cycle response curve is linear, then the correction lookup table has at least two duty cycles, including the duty cycle corresponding to the lowest dimming level (e.g., 0%) and the duty cycle that provides the preset brightness (e.g., ...). Figure 3 D t Or Figure 6 D m If the corresponding luminance-duty cycle response curve is non-linear, the correction lookup table will also record the duty cycle of at least one inflection point and the corresponding dimming level.

[0057] The duty cycle of the nth emitting unit can also be applied to other emitting units because, under the same manufacturing process, the luminance-duty cycle response curves of different emitting units should be similar. However, even using the same duty cycle, the luminance and parameters can still be remeasured. Specifically, another emitting unit (also called the second emitting unit) can be driven according to the default parameters, and the luminance of the second emitting unit can be measured. Then, the parameters can be adjusted so that the luminance of the second emitting unit matches the default luminance, and the adjusted parameters can be recorded in the calibration lookup table corresponding to the second emitting unit (also called the second calibration lookup table). Next, the inflection points (i.e., duty cycles) in Table 1 can be added to the second calibration lookup table, and the luminance corresponding to these duty cycles can be remeasured. The measured luminance or the corresponding dimming level will also be recorded in the second calibration lookup table. In this way, it is not necessary to find the inflection point of the luminance-duty cycle response curve of the second emitting unit again.

[0058] Please refer to Figure 1 The established correction lookup table is stored in the microcontroller 132. When a screen needs to be displayed, the timing controller 131 calculates a set value, which can be the dimming level or brightness. The microcontroller 132 receives the signal from the timing controller 131 and accesses the corresponding correction lookup table based on this set value. The output duty cycle is determined based on the duty cycle in the correction lookup table. Then, the current value of the light-emitting unit is determined based on the calculated output duty cycle and parameters to drive the light-emitting unit. Since the output current of each light-emitting area is corrected, uniform brightness characteristics can be obtained to avoid uneven brightness in the light-emitting areas. Combined with existing local dimming technology, it can be ensured that each light-emitting area after local dimming can achieve the desired zone brightness. The following example illustrates how the output duty cycle is determined.

[0059] First, if the luminance-duty cycle response curve is linear, circuit 130 obtains the corresponding and adjusted duty cycle based on the luminance on the luminance-duty cycle response curve as the output duty cycle. In other words, circuit 130 can interpolate the output duty cycle based on a linear function and the desired dimming level (or luminance). For example, the calibration lookup table records the adjusted parameter A. n_cal The duty cycle corresponding to the lowest dimming level (hereinafter referred to as D) n ) and the duty cycle corresponding to the maximum dimming level (hereinafter referred to as D) m (Not necessarily 100%). Based on the desired brightness (or dimming level), the following mathematical formula 3 can be used for calculation.

[0060] [Mathematical Expression 3]

[0061]

[0062] Where D k This indicates the output duty cycle, m represents the maximum dimming level (or maximum brightness), n represents the minimum dimming level (or minimum brightness), k represents the dimming level (or brightness) represented by the set value, and D... m D represents the duty cycle corresponding to the maximum dimming level (or maximum brightness). n This indicates the duty cycle corresponding to the lowest dimming level (or lowest brightness). The microcontroller 132 receives signals from the timing controller 131, thereby accessing the corresponding correction lookup table based on the desired brightness (or dimming level), and determining the output duty cycle D using mathematical formula 3 based on the duty cycle in the correction lookup table. k Next, based on the calculated output duty cycle D... k And the adjusted parameter A recorded in the correction lookup table. n_calThe current value of the light-emitting unit is determined to drive the light-emitting unit.

[0063] On the other hand, if the luminance-duty cycle response curve is non-linear, it has at least one inflection point. Each inflection point contains an inflection point luminance (or inflection point dimming level) and an inflection point duty cycle. These inflection point luminances and duty cycles are recorded in a calibration lookup table. Circuit 130 can interpolate and adjust the corresponding duty cycle based on the set value, the inflection point luminance, and the inflection point duty cycle as the output duty cycle. For example, Figure 7 This is a schematic diagram illustrating the interpolation output duty cycle according to one embodiment. Please refer to... Figure 7 B k The value represents the luminance. First, the closest luminance B is found in the calibration lookup table. k The luminance B of two adjacent inflection points i B i+1 Among them, luminance B k Brightness B greater than the inflection point i And less than the inflection point luminance B i+1 According to the inflection point luminance B i B i+1 The corresponding inflection point duty cycle D can be obtained from the correction lookup table. i D i+1 Next, the output duty cycle D can be interpolated according to the following mathematical formula 4. k .

[0064] [Mathematical Expression 4]

[0065]

[0066] The microcontroller 132 receives the signal from the timing controller 131, thereby accessing the corresponding correction lookup table according to the required brightness (or dimming level), and determining the output duty cycle D according to mathematical formula 4 based on the duty cycle in the correction lookup table. k It is worth noting that if the luminance B k Equivalent to a turning point luminance B in the correction lookup table i Then the duty cycle D at the inflection point can be directly output. i That is, the duty cycle D at the turning point i This means the output duty cycle D k Regardless of the scenario described above, the output duty cycle D is obtained. k Then, based on the output duty cycle D k And the parameter A in the correction lookup table n_cal This drives the corresponding light-emitting unit, and determines the current value of the light-emitting unit to drive it. Through this method, the desired brightness can be obtained.

[0067] Figure 8 This is a flowchart illustrating a calibration method for a display device according to an embodiment. This calibration method is performed collaboratively by the electronic terminal 110 and the display device 120. Please refer to... Figure 8 In step 801, the first light-emitting unit is driven to generate current according to preset parameters and a first duty cycle, and the first luminance of the first light-emitting unit is measured. In step 802, it is determined whether the first luminance is less than the preset luminance. If the result of step 802 is yes, then in step 803, the parameters are adjusted so that the first luminance of the first light-emitting unit meets the preset luminance, and the adjusted parameters are recorded in the calibration lookup table corresponding to the first light-emitting unit. If the result of step 802 is no, the parameter adjustment step is not performed, and in step 804, the parameters are directly recorded in the calibration lookup table corresponding to the first light-emitting unit. In step 805, the luminance-duty cycle response curve is defined. In step 806, it is determined whether the luminance-duty cycle response curve is linear. If the result of step 806 is yes, in step 807, the corresponding and adjusted duty cycle is obtained according to the luminance on the luminance-duty cycle response curve as the output duty cycle. If the result of step 806 is negative (non-linear), then the luminance-duty cycle response curve has at least one inflection point. In step 808, the corresponding and adjusted duty cycle is interpolated based on the inflection point luminance and duty cycle to serve as the output duty cycle. In step 809, the current value of the first light-emitting unit is determined based on the output duty cycle and the parameters in the correction lookup table to drive the first light-emitting unit. However, Figure 8 Each step has been explained in detail above and will not be repeated here. It is worth noting that... Figure 8 Each step can be implemented as multiple program codes or circuits, but the present invention is not limited thereto. Furthermore, Figure 8 The method can be used in conjunction with the above embodiments, or it can be used alone. In other words, Figure 8 Other steps can also be added between the various steps.

[0068] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

[0069] Explanation of reference numerals in the attached figures

[0070] 100: Current Correction System

[0071] 110: Electronic Terminal

[0072] 120: Display device

[0073] 130: Circuit

[0074] 131: Timing Controller

[0075] 132: Microcontroller

[0076] 140: Backlight Module

[0077] 141, 142: Light-emitting units

[0078] 150: Display panel

[0079] 151-153: Area

[0080] 310: Straight line

[0081] 320: Curve

[0082] 330: Brightness-Duty Cycle Response Curve

[0083] A t A n_cal Current value

[0084] D t D1~D7, D m D i D k D i+1 Duty cycle

[0085] B t B n B1~B7, B i B k B i+1 luminance

[0086] 401-408, 501-505: Fragments

[0087] 510, 610: Luminance-Duty Cycle Response Curves

[0088] 801-809: Steps

Claims

1. A display device, comprising: The display panel includes multiple areas; A backlight module includes a plurality of light-emitting units, wherein each of the plurality of regions corresponds to at least one of the plurality of light-emitting units; as well as The circuit includes at least one calibration lookup table, which corresponds to a first light-emitting unit among the plurality of light-emitting units, and the calibration lookup table records parameters and a plurality of duty cycles; The circuit accesses the correction lookup table to obtain one of the plurality of duty cycles and determines the output duty cycle; The circuit determines the current value of the first light-emitting unit based on the output duty cycle and the parameter, in order to drive the first light-emitting unit. The circuit drives the first light-emitting unit to generate multiple corresponding luminances based on the multiple duty cycles and the parameters. The multiple duty cycles and the multiple luminances define a luminance-duty cycle response curve. The luminance-duty cycle response curve is non-linear and has at least one inflection point. The at least one inflection point includes the inflection point luminance and the inflection point duty cycle. The circuit interpolates and adjusts the corresponding duty cycle based on the inflection point luminance and the inflection point duty cycle.

2. The display device as claimed in claim 1, wherein, The luminance-duty cycle response curve is a piecewise linear function composed of multiple linear functions.

3. The display device as claimed in claim 2, wherein, Each of the plurality of linear functions has a slope and a corresponding group duty cycle. The plurality of duty cycles corresponding to the plurality of linear functions include a first group duty cycle and a second group duty cycle. The minimum value of the first group duty cycle is equal to the maximum value of the second group duty cycle. The slope of the linear function corresponding to the first group duty cycle is greater than the slope of the linear function corresponding to the second group duty cycle.

4. The display device as claimed in claim 2, wherein, Each of the plurality of linear functions has a slope and a corresponding group duty cycle. The plurality of duty cycles corresponding to the plurality of linear functions include a first group duty cycle and a second group duty cycle. The minimum value of the first group duty cycle is equal to the maximum value of the second group duty cycle. The slope of the linear function corresponding to the first group duty cycle is less than the slope of the linear function corresponding to the second group duty cycle.

5. The display device of claim 2, wherein the circuit acquires a set value, the piecewise linear function has at least one inflection point, and the at least one inflection point of the piecewise linear function includes one of the plurality of duty cycles and a corresponding inflection point luminance. The circuit is used to interpolate the output duty cycle based on the set value and the plurality of duty cycles.

6. The display device of claim 5, wherein the circuit calculates the output duty cycle according to the following mathematical formula: Where D k This indicates the output duty cycle, B. k This indicates the luminance represented by the set value, where i represents the i-th inflection point among multiple inflection points, and the i-th inflection point includes the inflection point luminance B. i and duty cycle D i The (i+1)th inflection point contains the inflection point luminance B. i+1 and duty cycle D i+1 The luminance B k Brightness B greater than the inflection point i And less than the luminance B at the turning point i+1 .

7. The display device of claim 1, wherein the circuit performs a local dimming algorithm to calculate a set value corresponding to the first light-emitting unit.

8. A calibration method applicable to a display device, the display device including a display panel, a backlight module, and circuitry, the display panel including a plurality of regions, the backlight module including a plurality of light-emitting units, each of the plurality of regions corresponding to at least one of the plurality of light-emitting units, the calibration method comprising: Drive the first light-emitting unit among the plurality of light-emitting units according to the parameters and the first duty cycle to generate current, and measure the first light-emitting unit to obtain the first luminance of the first light-emitting unit; Determine whether the first luminance of the first light-emitting unit is less than the preset luminance. If the first luminance is less than the preset luminance, adjust the parameter so that the first luminance of the first light-emitting unit meets the preset luminance. Record the adjusted parameter in the first correction lookup table corresponding to the first light-emitting unit. Define the luminance-duty cycle response curve with the preset luminance, the adjusted parameter, and the first duty cycle. as well as The circuit determines whether the luminance-duty cycle response curve of the first light-emitting unit is linear or nonlinear. If the luminance-duty cycle response curve is linear, the circuit obtains the corresponding and adjusted duty cycle based on the luminance on the luminance-duty cycle response curve. If the luminance-duty cycle response curve is nonlinear, the luminance-duty cycle response curve has at least one inflection point, and the at least one inflection point includes the inflection point luminance and the inflection point duty cycle. The circuit interpolates the corresponding and adjusted duty cycle based on the inflection point luminance and the inflection point duty cycle.

9. The correction method as described in claim 8, wherein the step of determining whether the luminance-duty cycle response curve of the first light-emitting unit is linear or nonlinear includes: Multiple candidate duty cycles are set, and the first light-emitting unit is driven according to the multiple candidate duty cycles to obtain the corresponding multiple candidate luminance; Calculate multiple slopes of the luminance-duty cycle response curve based on the multiple candidate duty cycles and the multiple candidate luminances; as well as If the difference between the maximum and minimum slopes among the plurality of slopes is greater than a critical value, then the luminance-duty cycle response curve is determined to be nonlinear.

10. The correction method of claim 9, wherein the plurality of candidate duty cycles includes an initial duty cycle, and the correction method further comprises: From the plurality of candidate duty cycles, select one candidate duty cycle in ascending order of small to large, and calculate the corresponding slope based on the selected candidate duty cycle and the initial duty cycle to update the maximum slope and the minimum slope; as well as If the difference between the maximum slope and the minimum slope is greater than the critical value, the currently selected candidate duty cycle and the corresponding candidate luminance are set as the new inflection point.

11. The correction method as described in claim 8, further comprising: When the first luminance obtained by measuring the first light-emitting unit is greater than or equal to the preset luminance, the step of adjusting the parameter is not performed. Instead, the parameter is directly recorded in the first calibration lookup table corresponding to the first light-emitting unit, and the luminance-duty cycle response curve is defined with the preset luminance, the parameter, and the first duty cycle.

12. The correction method as described in claim 8, wherein, The circuit generates multiple candidate luminances by driving the first light-emitting unit based on multiple candidate duty cycles and the parameter. The multiple candidate duty cycles and the multiple candidate luminances define the luminance-duty cycle response curve, which is a piecewise linear function composed of multiple linear functions.

13. The correction method as described in claim 12, wherein, Each of the plurality of linear functions has a slope and a corresponding group duty cycle. The plurality of linear functions correspond to at least a first group duty cycle and a second group duty cycle. The minimum value of the first group duty cycle is equal to the maximum value of the second group duty cycle. The slope of the linear function corresponding to the first group duty cycle is greater than the slope of the linear function corresponding to the second group duty cycle.

14. The correction method as described in claim 12, wherein, Each of the plurality of linear functions has a slope and a corresponding group duty cycle. The plurality of duty cycles corresponding to the plurality of linear functions include a first group duty cycle and a second group duty cycle. The minimum value of the first group duty cycle is equal to the maximum value of the second group duty cycle. The slope of the linear function corresponding to the first group duty cycle is less than the slope of the linear function corresponding to the second group duty cycle.

15. The correction method as described in claim 8, wherein, The circuit drives the first light-emitting unit to generate a corresponding candidate luminance based on the candidate duty cycle and the parameter. The candidate duty cycle and the candidate luminance define the luminance-duty cycle response curve, which is a linear function.

16. The correction method of claim 8, wherein the plurality of light-emitting units further includes a second light-emitting unit, and the correction method further includes: The second light-emitting unit is driven according to the parameter, and the second luminance of the second light-emitting unit is measured. Adjust the parameter so that the second luminance of the second light-emitting unit matches the preset luminance, and record the adjusted parameter in the second correction lookup table corresponding to the second light-emitting unit; as well as If the first correction lookup table contains the at least one turning point, then the at least one turning point is added to the second correction lookup table.

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