Backlight control method, backlight controller and display device

Abstract

An embodiment of the present application provides a backlight control method, a backlight controller, and a display device. During the light-emitting process of the backlight unit of the display device, the waveform of the driving signal output by the backlight controller is a stepped sine wave, and the values of the sampling points on each step of the stepped sine wave gradually change according to the fluctuation trend of a preset sine wave. Since the high-frequency sine signal component contained in the sine wave is lower than that in the pulse-width modulation signal, the harmonic interference in the power supply unit circuit is reduced, the electromagnetic compatibility of the display device is improved, the influence of the oscillation of the high-frequency sine signal in the inductive components of the display device on the driving signal is reduced, and the stability and accuracy of the driving signal output by the backlight controller are improved.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of display technologies, and in particular, to a backlight control method, a backlight controller, and a display device. Background Art

[0002] A display device includes a power supply unit, a display panel, and a backlight unit. During the imaging process of the display device, the power supply unit supplies power to the display panel and the backlight unit. The display panel adjusts the state of its internal imaging structure and combines the backlight provided by the backlight unit to output a corresponding video image.

[0003] The backlight unit includes a backlight controller and a light-emitting unit group. After obtaining local dimming data, the backlight controller outputs a pulse-width modulation signal to regulate the light-emitting brightness of the light-emitting unit group. The pulse-width modulation signal is composed of superimposed sine wave signals of multiple frequencies, and there are a large number of high-frequency sine signals, which will introduce harmonic interference into the circuit of the power supply unit, affecting the regulation accuracy of the light-emitting brightness and the electromagnetic compatibility of the display device. Summary of the Invention

[0004] The present application provides a backlight control method, a backlight controller, and a display device to solve the technical problems of harmonic interference of the display device, low regulation accuracy of the light-emitting brightness, and poor electromagnetic compatibility of the display device.

[0005] In a first aspect, an embodiment of the present application provides a backlight control method for a display device. The display device includes a backlight unit, and the backlight unit includes a backlight controller and a light-emitting unit group. The method is applied to the backlight controller and includes:

[0006] Obtaining local dimming data, and outputting a driving signal to the light-emitting unit group based on the local dimming data to drive the light-emitting unit group to emit light;

[0007] The waveform of the driving signal is a stepped sine wave. A curve constructed by sequentially connecting multiple sampling points in the stepped sine wave is a preset sine wave. Different effective values of the stepped sine wave correspond one-to-one to different backlight brightness levels generated by the light-emitting unit group, where the multiple sampling points are respectively located at preset positions of multiple steps of the stepped sine wave.

[0008] In the above technical solution, during the light-emitting process of the backlight unit of the display device, the waveform of the driving signal output by the backlight controller is a stepped sine wave. The values of the sampling points on each step of the stepped sine wave gradually change according to the fluctuation trend of the preset sine wave. Since the high-frequency sine signal component contained in the sine wave is lower than that in the pulse-width modulation signal, the harmonic interference in the power supply unit circuit is reduced, the electromagnetic compatibility of the display device is improved, the influence of the oscillation of the high-frequency sine signal in the inductive components of the display device on the driving signal is reduced, and the stability and accuracy of the driving signal output by the backlight controller are improved.

[0009] Optionally, multiple steps of the stepped sine wave are of equal width, and the distance of each sampling point from the same-side end point of the step where it is located is the same;

[0010] The effective value of the stepped sine wave is the average value of the values of the sampling points on multiple steps within one cycle of the stepped sine wave.

[0011] In the above technical solution, multiple steps of the stepped sine wave are of equal width and the distance of each sampling point from the same-side end point of the step is the same, which ensures the standardization of generating the stepped sine wave and makes the stepped sine wave easy to implement.

[0012] Optionally, one frame display period includes a plurality of consecutive stepped sine waves;

[0013] Within one frame display period, the periods of the plurality of stepped sine waves are the same, and the waveforms of the plurality of stepped sine waves are the same.

[0014] In the above technical solution, setting a plurality of consecutive stepped sine waves in one frame display period makes the light-emitting intensity of the light-emitting unit group more uniform, ensuring the display quality of the display device. The periods and waveforms of the plurality of stepped sine waves in one frame display period are the same, which is convenient for controlling the backlight unit group.

[0015] Optionally, the backlight controller includes configuration information;

[0016] Outputting a driving signal to the light-emitting unit group based on the local dimming data includes:

[0017] Determining a dimming mode based on the configuration information; different configuration information corresponds to different dimming modes one by one;

[0018] Outputting a driving signal to the light-emitting unit group based on the dimming mode and the local dimming data.

[0019] In the above technical solution, multiple optional configuration information is set in the backlight controller, corresponding to multiple dimming modes, so as to meet the multiple dimming requirements of users, improve the application universality of the backlight control method, and prevent the display from being abnormal due to the abnormality of some dimming modes, thereby improving the robustness of the application of this method.

[0020] Optionally, within one frame display period, the preset sine waves corresponding to the multiple stepped sine waves fluctuate around the same preset horizontal axis within a preset range, and the preset horizontal axis is parallel to the time axis;

[0021] The dimming mode includes a standard sine dimming mode or a non-standard sine dimming mode, and the non-standard sine dimming mode uses a sine amplitude dimming or a sine period dimming method for dimming.

[0022] In the above technical solution, when the multiple stepped sine waves fluctuate within a set preset range, dimming is performed through the standard sine dimming mode or the non-standard sine dimming mode, which improves the flexibility of dimming.

[0023] Optionally, in the standard sine dimming mode, within one period of the preset sine wave, the duration of the positive half-cycle is the same as the duration of the negative half-cycle, and the amplitude of the preset sine wave within the positive half-cycle is the same as the amplitude of the preset sine wave within the negative half-cycle.

[0024] In the above technical solution, since the amplitude and duration of the preset sine wave corresponding to the stepped sine wave in the standard sine dimming mode are the same in the positive half-cycle and the negative half-cycle, the method of calculating the stepped sine wave is simpler and more convenient for the control of the backlight unit.

[0025] Optionally, the stepped sine wave output by the backlight controller in the first display period is the first stepped sine wave, and the stepped sine wave output in the second display period is the second stepped sine wave. When the preset horizontal axis corresponding to the first stepped sine wave is different from the preset horizontal axis corresponding to the second stepped sine wave, the effective value of the first stepped sine wave is different from the effective value of the second stepped sine wave.

[0026] Optionally, when using the sine amplitude dimming method in the non-standard sine dimming mode, within one period of the preset sine wave, when the duration of the positive half-cycle is the same as the duration of the negative half-cycle, the amplitude of the preset sine wave within the positive half-cycle is different from the amplitude of the preset sine wave within the negative half-cycle.

[0027] In the above technical solution, when dimming using the sine amplitude dimming method, the amplitude of the positive half-cycle and the amplitude of the negative half-cycle of the preset sine wave of the stepped sine wave are adjustable independently. When the effective value of the stepped sine wave changes within a relatively small range, the position of the preset horizontal axis is not moved, and only the waveform of the half-cycle is adjusted. When the effective value changes significantly, the preset horizontal axis is adjusted to improve the adjustment accuracy.

[0028] Optionally, when dimming using the sine period dimming method in the non-standard sine dimming mode, within one period of the preset sine wave, the duration of the positive half-cycle and the duration of the negative half-cycle are different, and the ratio of the duration of the positive half-cycle to the duration of the negative half-cycle is equal to the ratio of the amplitude of the positive half-cycle to the amplitude of the negative half-cycle.

[0029] In the above technical solution, when dimming using the sine period dimming method, the duration of the positive half-cycle and the duration of the negative half-cycle of the stepped sine wave are adjustable. When the effective value of the stepped sine wave changes within a relatively small range, the position of the preset horizontal axis is not moved, and only the duration of the half-cycle is adjusted. When the effective value changes significantly, the preset horizontal axis is adjusted to improve the adjustment accuracy. In addition, the ratio of the duration of the positive half-cycle to the duration of the negative half-cycle is equal to the ratio of the amplitude of the positive half-cycle to the amplitude of the negative half-cycle, ensuring the smoothness of the waveform change between the positive half-cycle and the negative half-cycle and improving the display effect.

[0030] Optionally, the backlight controller includes multiple driving chips, and each driving chip includes multiple output terminals;

[0031] Based on the dimming mode and the local dimming data, outputting a driving signal to the light-emitting unit group includes:

[0032] Controlling the driving chips to simultaneously output multiple driving signals from the multiple output terminals, where the periods of the stepped sine waves of the multiple driving signals are the same, the amplitudes of the positive half-cycles are the same, the amplitudes of the negative half-cycles are the same, and the phases are different from each other;

[0033] Wherein, the phases of the stepped sine waves output from any two output terminals are integer multiples of the reference phase, and the reference phase is the quotient of the period phase divided by the number of output terminals of the driving chip.

[0034] In the above technical solution, in the backlight controller, when multiple output terminals of the driving chip drive multiple light-emitting unit groups to emit light, the phases of the driving signals output from the multiple output terminals are evenly staggered, so that the total value change of the driving signals output by the driving chip fluctuates little, which can reduce the interference between adjacent output terminals and further improve the electromagnetic compatibility.

[0035] In a second aspect, the present application provides a backlight controller, and the backlight controller is used to execute any one of the backlight control methods described in the first aspect.

[0036] In a third aspect, the present application provides a display device, including the backlight controller described in the second aspect.

[0037] In a backlight control method, a backlight controller, and a display device provided by an embodiment of the present application, during the light-emitting process of a backlight unit of the display device, the waveform of a driving signal output by the backlight controller is a stepped sine wave, and the values of sampling points on each step in the stepped sine wave gradually change according to the fluctuation trend of a preset sine wave. Since the high-frequency sine signal component included in the sine wave is lower than that in a pulse-width modulation signal, harmonic interference in a power supply unit circuit is reduced, the electromagnetic compatibility of the display device is improved, the influence of oscillation of the high-frequency sine signal in an inductive device of the display device on the driving signal is reduced, and the stability and accuracy of the driving signal output by the backlight controller are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application and used together with the specification to explain the principles of the present application.

[0039] Figure 1 is a schematic structural diagram of a display device provided by the present application according to an exemplary embodiment;

[0040] Figure 2 is a schematic diagram showing the relationship between a pulse-width modulation signal and a multi-frequency sine wave provided by the present application according to an exemplary embodiment;

[0041] Figure 3 is a schematic flowchart of a backlight control method of a backlight controller provided by the present application according to an exemplary embodiment;

[0042] Figure 4 is a schematic diagram of a stepped sine wave in a standard sine dimming mode provided by the present application according to an exemplary embodiment;

[0043] Figure 5 is a schematic diagram of a stepped sine wave in an application of a sine amplitude dimming method provided by the present application according to an exemplary embodiment;

[0044] Figure 6 is a schematic diagram of a stepped sine wave in an application of a sine period dimming method provided by the present application according to an exemplary embodiment;

[0045] Figure 7 is a schematic structural diagram of a backlight controller provided by the present application according to an exemplary embodiment;

[0046] Figure 8 is a schematic diagram of the phase relationship of multiple stepped sine waves output by a driving chip provided by the present application according to an exemplary embodiment.

[0047] Through the above-mentioned accompanying drawings, specific embodiments of the present application have been shown, and more detailed descriptions will be given hereinafter. These drawings and written descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Detailed Embodiments

[0048] Exemplary embodiments will be described in detail herein, and examples thereof are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numerals in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0049] It should be noted that, in this document, the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article or device comprising such element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or different meanings, and their specific meanings need to be determined based on their explanations in the specific embodiments or further in combination with the context of the specific embodiments.

[0050] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0051] A display device is a device that can output images or videos, that is, a device that generates corresponding images according to input image data or video data. A schematic structural diagram of the display device can be referred to Figure 1 as shown, and it includes a main controller 10, a display panel 20, a backlight unit 30, and a power supply unit 40. The main controller 10 is electrically connected to the display panel 20 and the backlight unit 30 respectively, and the power supply unit 40 is electrically connected to the main controller 10, the display panel 20, and the backlight unit 30 respectively. The backlight unit 30 is overlapped with the display panel 20, and the backlight unit 30 is disposed on a side away from the display surface of the display panel 20.

[0052] After the main controller 10 obtains image data or video data, it outputs local dimming data to the backlight unit 30 and display data to the display panel 20. The display panel 20 adjusts the state of its internal imaging structure based on the display data, and the backlight unit 30 emits light based on the local dimming data, and the backlight is projected onto the display panel 20 to display the corresponding image.

[0053] In some embodiments, the backlight unit 30 includes a backlight controller 301 and a light-emitting unit group 302. The backlight controller 301 is electrically connected to the main controller 10, and the backlight controller 301 is electrically connected to the light-emitting unit group 302. The backlight controller 301 obtains local dimming data and outputs a driving signal to drive the light-emitting unit group 302 to emit light.

[0054] In some embodiments, the driving signal output by the backlight controller 301 is a pulse-width modulation signal. The backlight controller 301 adjusts the light-emitting brightness of the light-emitting unit group 302 by regulating at least one of the duty cycle and amplitude of the pulse-width modulation signal.

[0055] The pulse-width modulation signal is a square-wave signal, and the generation of the square-wave signal is based on the superposition of sine-wave signals of multiple frequencies. In some embodiments, the relationship diagram between the pulse-width modulation signal and the sine signals of multiple frequencies during the rising-edge level change period can be referred to Figure 2 as shown. From Figure 2 it can be seen that when the level of the pulse-width modulation signal changes, in order to modulate the voltage value of the pulse-width modulation signal, a large number of high-frequency signals need to be superimposed. As shown by the high-frequency fluctuations on the pulse-width modulation signal in the figure, it is particularly obvious during the level mutation period. This high-frequency signal is also called a high-frequency harmonic, and this harmonic will interfere with the power supply line and affect the normal operation of other electronic devices.

[0056] More specifically, in the circuit structure of the display device, wires and inductive components are necessary components. Among them, the wires include traces on the printed circuit board and inter-board connections, which can also be equivalent to inductive components. When high-frequency harmonics exist, the high-frequency harmonics will perform frequent charging and discharging operations in the inductive components, generating oscillations, which are likely to cause noise in the circuit, thereby affecting the accuracy of the output driving signal and the regulation accuracy of the light-emitting brightness of the light-emitting unit group 302.

[0057] In addition, the complex magnetic field generated by high-frequency electrical signals will interfere with external devices and affect the operation of external devices. It will also be affected by external electromagnetic fields, resulting in signal distortion and affecting the normal and stable operation of the display device.

[0058] The present application provides a backlight control method, a backlight controller, and a display device, aiming to solve the technical problems of harmonic interference in the display device, low regulation accuracy of the light emission brightness, and poor electromagnetic compatibility of the display device. The technical concept of the present application is as follows: during the light emission process of the backlight unit of the display device, the waveform of the driving signal output by the backlight controller is a stepped sine wave, and the values of the sampling points on each step of the stepped sine wave gradually change according to the fluctuation trend of the preset sine wave. Since the high-frequency sine signal component contained in the sine wave is lower than that in the pulse width modulation signal, the harmonic interference in the power supply unit circuit is reduced, the electromagnetic compatibility of the display device is improved, the influence of the oscillation of the high-frequency sine signal in the inductive components of the display device on the driving signal is reduced, and the stability and accuracy of the driving signal output by the backlight controller are improved.

[0059] The backlight control method provided by the present application will be explained below. Figure 3 It is a schematic flowchart of the backlight control method of the display device provided by the present application according to an exemplary embodiment. As Figure 3 shown, the method includes:

[0060] S101. The backlight controller obtains local dimming data.

[0061] Among them, the local dimming data is the data generated after the main controller obtains the image data or video data, and is used to separately regulate the light emission brightness of multiple regions in the backlight unit, so as to improve the driving accuracy of the backlight. In some embodiments, the backlight unit includes multiple LEDs, and the local dimming data is the data used to control the light emission of the LEDs in each region.

[0062] S102. The backlight controller outputs a driving signal to the light emitting unit group based on the local dimming data to drive the light emitting unit group to emit light. The waveform of the driving signal is a stepped sine wave, and the curve constructed by sequentially connecting multiple sampling points in the stepped sine wave is a preset sine wave. Different effective values of the stepped sine wave correspond one-to-one to different backlight brightnesses generated by the light emitting unit group. Among them, multiple sampling points are respectively located at preset positions of multiple steps of the stepped sine wave.

[0063] In some embodiments, the driving signal output by the backlight controller based on the local dimming data includes a current signal, and the light emitting unit group regulates its light emission brightness based on the current value and the current duration of the current signal. Among them, the larger the current value of the current signal, the brighter the instantaneous brightness of the light emitting unit group, and the longer the duration of the current signal, the brighter the brightness of the light emitting unit group in the frame display period.

[0064] In some embodiments, the waveform of the current signal is a stepped sine wave, that is, the current step value of the current signal changes according to a sine wave. Figure 4Schematic diagram of a step sine wave provided by the present application according to an exemplary embodiment, wherein each step value of the step sine wave 51 is adjusted according to the value change of the preset sine wave 50, wherein the preset sine wave 50 has multiple step sampling points 52, and the multiple sine values determined by the multiple step sampling points 52 on the preset sine wave are used as the values of the sampling points on the multiple steps in the step sine wave, and the values can be as follows Figure 4 The sine value of the step sampling point 52 corresponding to the earlier one of the two adjacent points can also be the sine value of the step sampling point 52 corresponding to the later one of the two adjacent points. The step value change moment is within the time range defined by the two adjacent step sampling points 52. Figure 4 In the example, the step change moment is the moment corresponding to the earlier step sampling point 52 among the two adjacent points.

[0065] The stepped sine wave 51 follows the periodic fluctuations of the preset sine wave 50. In one cycle of the stepped sine wave 51, the sum of the products of each step value and the corresponding step duration, divided by the cycle length, is the effective value of the stepped sine wave 51, which is proportional to the uniform display brightness of the light-emitting unit group within one cycle.

[0066] The backlight controller can adjust the brightness of the light emitting unit group by regulating the effective value of the step sine wave 51 .

[0067] In the above technical solution, when the backlight unit of the display device is emitting light, the waveform of the driving signal output by the backlight controller is a stepped sine wave, and the values of the sampling points on each step in the stepped sine wave gradually change according to the fluctuation trend of the preset sine wave. Since the high-frequency sinusoidal signal component contained in the sine wave is lower than the high-frequency sinusoidal signal component in the pulse width modulation signal, the harmonic interference in the power supply unit circuit is reduced, the electromagnetic compatibility of the display device is improved, the influence of the oscillation of the high-frequency sinusoidal signal in the inductive device of the display device on the driving signal is reduced, and the stability and accuracy of the driving signal output by the backlight controller are improved.

[0068] In some embodiments, the multiple steps of the stepped sine wave 51 are of equal width, and each step sampling point 52 is equidistant from the endpoint on the same side of the step in which it resides. That is, each step sampling point 52 samples the preset sine wave 50 at the same time interval, and the sampled value is used as the value of the step. The duration of each step is the same, and each step sampling point 52 is equidistant from the change point on the left side of the step, that is, the time distance from the change point on the right side of the step is the same, which facilitates unified control. In this case, the effective value of the stepped sine wave 51 is the average of the values of the sampling points on multiple steps within a cycle of the stepped sine wave 51.

[0069] In the above technical solution, the multi-steps of the stepped sine wave have equal widths and the sampling points on each step are at the same distance from the same-side end point, which ensures the standardization of the generated stepped sine wave and makes the stepped sine wave easy to implement.

[0070] In some embodiments, one frame display period includes a plurality of consecutive stepped sine waves 51. Within one frame display period, the periods of the plurality of stepped sine waves are the same, and the waveforms of the plurality of stepped sine waves are the same. For example, within the current frame display period (the first frame display period), there are 50 consecutive stepped sine waves 51. The waveform changes of these 50 stepped sine waves 51 are the same, that is, both the period and amplitude change situations are the same. When entering the next frame display period (the second frame display period), the next frame display period may still include 50 consecutive stepped sine waves 51, but the amplitude change has nothing to do with the amplitude change of the stepped sine waves 51 within the first frame display period and may be different; it may also include 60 consecutive stepped sine waves 51 when entering the next frame display period (the second frame display period), as long as it is ensured that the plurality of stepped sine waves within the second frame display period fluctuate according to the period.

[0071] In the above technical solution, setting a plurality of consecutive stepped sine waves in one frame display period makes the light-emitting intensity of the light-emitting unit group more uniform, ensuring the display quality of the display device. The periods and waveforms of the plurality of stepped sine waves in one frame display period are the same, which is convenient for controlling the backlight unit group.

[0072] In some embodiments, the backlight controller includes configuration information. When the backlight controller 310 outputs a driving signal to the light-emitting unit group based on the local dimming data, it specifically includes:

[0073] The backlight controller 310 determines the dimming mode based on the configuration information, and outputs a driving signal to the light-emitting unit group based on the dimming mode and the local dimming data. Among them, the configuration information can be the information pre-set in the backlight controller 310, or the data pre-stored in the main controller 10 and transmitted by the main controller 10 simultaneously when transmitting the local dimming data, or the configuration information written by the user into the main controller 10 through the input device of the display device. Different configuration information corresponds to different dimming modes one by one. Under the determined dimming mode, the backlight controller 310 modulates the waveform of the driving signal based on the local dimming data to drive the light-emitting unit group 302 to emit light.

[0074] In the above technical solution, multiple optional configuration information is set in the backlight controller, corresponding to multiple dimming modes, to meet the various dimming needs of users, improving the application universality of the backlight control method, and also preventing the situation of abnormal display caused by some abnormal dimming modes, improving the robustness of the application of this method.

[0075] The following explains various dimming modes that can be set by the backlight controller 310 and the waveforms of the output drive signals in each dimming mode respectively.

[0076] In some embodiments, the dimming mode includes a standard sine dimming mode. A schematic diagram of the stepped sine wave 51 output by the backlight controller 310 in the standard sine dimming mode and the corresponding preset sine wave 50 can be referred to Figure 4 as shown.

[0077] Within one frame display period, the preset sine waves 50 corresponding to multiple stepped sine waves 51 fluctuate within a preset range around the same preset horizontal axis 53 within the preset range, and the preset horizontal axis 53 is parallel to the time axis. Among them, the preset range is the fluctuation range that the value of the stepped sine wave 51 cannot exceed. [[ID=I0]]

[0078] The period of the preset sine wave 50 is the same as that of the stepped sine wave 51. One period T of the preset sine wave 50 includes a positive half-period T1 and a negative half-period T2. Within the positive half-period T1, the preset sine wave 50 is located above the preset horizontal axis 53, and within the negative half-period T2, the preset sine wave 50 is located below the preset horizontal axis 53.

[0079] In the standard sine dimming mode, within one period T of the preset sine wave 50, the duration of the positive half-period T1 is the same as that of the negative half-period T1, and the amplitude of the preset sine wave 50 within the positive half-period T1 is the same as the amplitude of the preset sine wave 50 within the negative half-period T2. Among them, the amplitude of the preset sine wave 50 within the positive half-period T1 is the difference between the maximum value of the preset sine wave 50 within the positive half-period T1 and the corresponding value of the preset horizontal axis 53, and the amplitude of the preset sine wave 50 within the negative half-period T2 is the absolute value of the difference between the minimum value of the preset sine wave 52 within the negative half-period T2 and the corresponding value of the preset horizontal axis 53. In Figure 4 the waveform diagram shown, if the amplitude of the preset sine wave 50 within the positive half-period T1 and the negative half-period T2 is 1, then the effective value of the stepped sine wave 51 corresponding to the preset sine wave 50 is equal to the value corresponding to the preset horizontal axis 53.

[0080] In some embodiments, the stepped sine wave output by the backlight controller within the first display period is the first stepped sine wave, and the stepped sine wave output within the second display period is the second stepped sine wave. When the preset horizontal axis corresponding to the first stepped sine wave is different from the preset horizontal axis corresponding to the second stepped sine wave, the effective value of the first stepped sine wave is different from the effective value of the second stepped sine wave.

[0081] In the above technical solution, since the preset sine wave corresponding to the stepped sine wave in the standard sine dimming mode has the same amplitude and duration within the positive half-period and the negative half-period, the method of calculating the stepped sine wave is simpler, which is convenient for the control of the backlight unit.

[0082] In some embodiments, the dimming mode includes a non-standard sine dimming mode, and the non-standard sine dimming mode performs dimming by using sine amplitude dimming or sine period dimming methods.

[0083] When dimming is performed by using the sine amplitude dimming method in the non-standard sine dimming mode, a waveform schematic diagram of the stepped sine wave 51 output by the backlight controller 310 and the corresponding preset sine wave 50 can be referred to Figure 5 as shown.

[0084] Similar to the Figure 4 waveform shown, within one frame display period, the preset sine waves 50 corresponding to multiple stepped sine waves 51 fluctuate around the same preset horizontal axis 53 within a preset range, and the preset horizontal axis 53 is parallel to the time axis. The period T of the preset sine wave 50 includes a positive half-period T1 and a negative half-period T2. Within the positive half-period T1, the preset sine wave 50 is located above the preset horizontal axis 53, and within the negative half-period T2, the preset sine wave 50 is located below the preset horizontal axis 53.

[0085] When dimming is performed by using the sine amplitude dimming method, when the durations of the positive half-period T1 and the negative half-period T2 are the same within one period T of the preset sine wave 50, the difference from the Figure 4 waveform shown is that the amplitude of the preset sine wave 50 within the positive half-period T1 is different from the amplitude of the preset sine wave 50 within the negative half-period T2.

[0086] In some embodiments, for the stepped sine waves 51 fluctuating around the same preset horizontal axis, the amplitude of the preset sine wave 50 corresponding to the stepped sine wave 51 within the positive half-period T1 is positively correlated with the effective value of the stepped sine wave 51, and the amplitude of the preset sine wave 50 corresponding to the stepped sine wave 51 within the negative half-period T2 is negatively correlated with the effective value of the stepped sine wave 51. Specifically, the larger the amplitude of the preset sine wave 50 corresponding to the stepped sine wave 51 within the positive half-period T1, the larger the effective value of the stepped sine wave 51; the larger the amplitude of the preset sine wave 50 corresponding to the stepped sine wave 51 within the negative half-period T2, the smaller the effective value of the stepped sine wave 51.

[0087] In some embodiments, when the set output current value of the display device cannot be lower than a preset threshold (such as 0.5 mA), the standard stepped sine wave that can originally fluctuate between 0 - 2 mA cannot be achieved, and it can be achieved by lowering the value of the preset horizontal axis 53 and reducing the amplitude of the negative half-period T2.

[0088] In some other embodiments, when the stepped sine wave output by the backlight controller 301 is as Figure 4When the standard stepped sine wave shown is adjusted for increasing the effective value according to the standard sine dimming mode, only the value of the preset horizontal axis 53 can be moved upward, and the accuracy of adjusting the effective value is low; when performing curve adjustment according to the sine amplitude dimming method, the amplitude of the negative half-cycle T2 can be preferentially reduced to increase the effective value. When adjusting the steps of the negative half-cycle T2 cannot achieve the target effective value or the achieved effect is not good (for example, the curve connection effect of the preset sine waves 50 in the positive half-cycle T1 and the negative half-cycle T2 is poor), then the value of the preset horizontal axis 53 is moved upward, and the adjustment accuracy of the effective value can be improved.

[0089] In the above technical solution, when dimming using the sine amplitude dimming method, the amplitude of the positive half-cycle and the amplitude of the negative half-cycle of the preset sine wave of the stepped sine wave can be adjusted separately. When the change range of the effective value of the stepped sine wave is small, the position of the preset horizontal axis is not moved, and only the waveform of the half-cycle is adjusted. When the effective value changes greatly, the preset horizontal axis is adjusted again to improve the adjustment accuracy.

[0090] In some embodiments, when using the sine period dimming method in the non-standard sine dimming mode, the waveform diagrams of the stepped sine wave 51 output by the backlight controller 310 and the corresponding preset sine wave 50 can be referred to Figure 6 as shown.

[0091] Similar to Figure 4 、 Figure 5 the waveforms shown, within one frame display period, the preset sine waves 50 corresponding to multiple stepped sine waves 51 fluctuate around the same preset horizontal axis 53 within a preset range, and the preset horizontal axis 53 is parallel to the time axis.

[0092] The period of the preset sine wave 50 includes a positive half-cycle T1 and a negative half-cycle T2. Within the positive half-cycle T1, the preset sine wave 50 is located above the preset horizontal axis 53, and within the negative half-cycle T2, the preset sine wave 50 is located below the preset horizontal axis 53.

[0093] Different from Figure 4 、 Figure 5 the waveforms shown, when using the sine period dimming method, within one cycle of the preset sine wave 50, the duration of the positive half-cycle T1 and the duration of the negative half-cycle T2 are different, and the ratio of the duration of the positive half-cycle T1 to the duration of the negative half-cycle T2 is equal to the ratio of the amplitude of the positive half-cycle T1 to the amplitude of the negative half-cycle T2, so that the curve of the preset sine wave 50 can be smoothly connected from the curve of the positive half-cycle T1 to the curve of the lower half-cycle T2.

[0094] In some embodiments, for the stepped sine wave 51 that fluctuates around the same preset horizontal axis 53, the duration of the positive half-cycle T1 of the stepped sine wave 51 is positively correlated with the effective value of the stepped sine wave 51, and the duration of the negative half-cycle T2 of the stepped sine wave 51 is negatively correlated with the effective value of the stepped sine wave 51. Specifically, the longer the duration of the positive half-cycle T1 of the stepped sine wave 51, the greater the effective value of the stepped sine wave 51; the longer the duration of the negative half-cycle T2 of the stepped sine wave 51, the smaller the effective value of the stepped sine wave 51.

[0095] In the above technical solution, when adopting the sine cycle dimming method, the duration of the positive half-cycle and the duration of the negative half-cycle of the stepped sine wave are adjustable. When the change range of the effective value of the stepped sine wave is small, without moving the position of the preset horizontal axis, only the duration of the half-cycle is adjusted. When the effective value changes greatly, the preset horizontal axis is adjusted to improve the adjustment accuracy. In addition, the ratio of the duration of the positive half-cycle to the duration of the negative half-cycle is equal to the ratio of the amplitude of the positive half-cycle to the amplitude of the negative half-cycle, ensuring the smoothness of the waveform change between the positive half-cycle and the negative half-cycle and improving the display effect.

[0096] When adopting the sine amplitude dimming method and the sine cycle dimming method in the non-standard sine dimming mode, the dimming can be performed in accordance with a preset order. For example, first use the sine amplitude dimming method for dimming and then use the sine cycle dimming method for dimming, which is not limited here. The following is an explanation in the order of first sine amplitude dimming and then sine cycle dimming. If the waveform of the positive half-cycle remains unchanged and the waveform of the negative half-cycle is adjusted for dimming, first keep the duration of the positive half-cycle and the duration of the negative half-cycle the same, adjust the amplitude of the waveform of the negative half-cycle, and then perform the transformation of the period and amplitude on the waveform of the negative half-cycle. The ratio of the duration of the negative half-cycle before the transformation to the duration of the negative half-cycle after the transformation needs to be consistent with the ratio of the amplitude of the negative half-cycle before the transformation to the amplitude of the negative half-cycle after the transformation to further improve the adjustment accuracy.

[0097] In some embodiments, the structure of the backlight controller 301 is as Figure 7 shown, including at least one dimming controller 3011 and multiple driving chips 3012. The dimming controller 3011 is electrically connected to at least one group of driving chips 3012. Each group of driving chips 3012 includes multiple driving chips 3012, and each driving chip 3012 can be electrically connected in parallel or in cascade. The driving chip 3012 includes multiple output terminals, and the output terminals are correspondingly electrically connected to the light emitting unit group 302. In Figure 7 the shown circuit structure, the driving chip 3012 has 4 output terminals, which are respectively electrically connected to four light emitting unit groups 302.

[0098] The dimming controller 3011 is electrically connected to the main controller 10 and obtains local dimming data from the main controller 10. In some embodiments, the dimming controller 3011 can further process the local dimming data to improve the image quality; in some embodiments, the dimming controller 3011 can map the local dimming data to a plurality of driving chips 3012 to which it is correspondingly electrically connected and output; in some embodiments, the dimming controller 3011 can output the local dimming data obtained after protocol conversion.

[0099] Based on the obtained and processed local dimming data, the driving chip 3012 outputs a driving signal to drive the light-emitting unit group 302 to emit light.

[0100] Then, based on the dimming mode and the local dimming data, the backlight controller 301 outputs a driving signal to the light-emitting unit group 302, specifically including:

[0101] The backlight controller 301 controls the driving chip 3012 to simultaneously output a plurality of driving signals from a plurality of output terminals. The periods of the stepped sine waves of the plurality of driving signals are the same, the amplitudes of the positive half-cycles are the same, the amplitudes of the negative half-cycles are the same, and the phases are different from each other; wherein, the phases of the stepped sine waves output from any two output terminals are integer multiples of the reference phase, and the reference phase is the quotient of the cycle phase divided by the number of output terminals of the driving chip.

[0102] The following is an explanation in combination with Figure 8 the waveform diagram shown. One cycle phase of the stepped sine wave is 2π. When the driving chip 3012 outputs driving signals from its respective output terminals, the periods and waveforms of the stepped sine waves are the same, only the phases are different. Divide 2π evenly by the number of output terminals N of the driving chip 3012, and determine N phase values from [0, 2π):

[0103] 0, , , ……, .

[0104] And correspondingly allocate them to N output terminals as the phases of the output terminals. As shown in the waveform diagram in Figure 8 , if the driving chip 3012 has 4 output terminals to output driving chips, then divide the cycle phase into 4 equal parts, and the phases of the signals output from the output terminals are sequentially spaced 90°, then the reference phase is 90°, and the phases of each stepped sine wave are 0 to 3 times the reference phase.

[0105] In the above technical solution, in the backlight controller, when a plurality of output terminals of the driving chip drive a plurality of light-emitting unit groups to emit light, the phases of the driving signals output from the plurality of output terminals are evenly staggered, so that the total value change of the driving signals output by the driving chip is small, the interference between adjacent output terminals can be reduced, and the electromagnetic compatibility can be further improved.

[0106] In some embodiments, the present application provides a backlight controller 301, which is used to execute the backlight control method in the foregoing embodiments, and will not be elaborated herein.

[0107] In some embodiments, the present application provides a display device, including the backlight controller 301 in the foregoing embodiments.

[0108] Those skilled in the art will readily conceive of other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include common general knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and embodiments are only regarded as exemplary, and the true scope and spirit of the present application are pointed out by the following claims.

[0109] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A backlight control method for a display device, characterized in that The display device includes a backlight unit, the backlight unit includes a backlight controller and a light emitting unit group, the method is applied to the backlight controller, the backlight controller includes configuration information; the method includes: Obtain local dimming data; outputting a driving signal to the light emitting unit group based on the local dimming data to drive the light emitting unit group to emit light; The waveform of the driving signal is a stepped sine wave, a curve constructed by sequentially connecting a plurality of sampling points in the stepped sine wave is a preset sine wave, different effective values of the stepped sine wave correspond one-to-one to different backlight brightnesses generated by the light-emitting unit groups, wherein the plurality of sampling points are respectively located at preset positions of a plurality of steps of the stepped sine wave; The method further comprises: In one frame display period, the preset sine waves corresponding to the plurality of step sine waves fluctuate around the same preset horizontal axis within a preset range, and the preset horizontal axis is parallel to the time axis; A dimming mode is determined based on the configuration information; the dimming mode includes a standard sinusoidal dimming mode or a non-standard sinusoidal dimming mode, and the non-standard sinusoidal dimming mode adopts sinusoidal amplitude dimming or sinusoidal period dimming for dimming; wherein different configuration information corresponds one-to-one to different dimming modes.

2. The method according to claim 1, wherein The multiple steps of the stepped sine wave have equal widths, and the distances between each sampling point and the endpoint on the same side of the step where it is located are the same; The effective value of the step sine wave is the average of the values of the sampling points on multiple steps within one cycle of the step sine wave.

3. The method according to claim 2, wherein One frame display period includes multiple continuous step sine waves; In one frame display period, the periods of the multiple step sine waves are the same, and the waveforms of the multiple step sine waves are the same.

4. The method according to any one of claims 1 to 3, characterized in that Outputting a driving signal to the light emitting unit group based on the local dimming data includes: Based on the dimming mode and the local dimming data, a driving signal is output to the light emitting unit group.

5. The method according to claim 1, wherein In the standard sinusoidal dimming mode, within one cycle of the preset sine wave, the duration of the positive half cycle is the same as the duration of the negative half cycle, and the amplitude of the preset sine wave in the positive half cycle is the same as the amplitude of the preset sine wave in the negative half cycle.

6. The method according to claim 5, characterized in that, The step sine wave output by the backlight controller in the first display period is a first step sine wave, and the step sine wave output in the second display period is a second step sine wave. When the preset horizontal axis corresponding to the first step sine wave is different from the preset horizontal axis corresponding to the second step sine wave, the effective value of the first step sine wave is different from the effective value of the second step sine wave.

7. The method according to claim 1, wherein When sinusoidal amplitude dimming is used in the non-standard sinusoidal dimming mode, if the duration of the positive half cycle and the duration of the negative half cycle are the same within one cycle of the preset sinusoidal wave, the amplitude of the preset sinusoidal wave in the positive half cycle and the amplitude of the preset sinusoidal wave in the negative half cycle are different.

8. The method according to claim 1, characterized in that When dimming in the non-standard sine dimming mode using the sine period dimming method, the duration of the positive half-cycle is different from the duration of the negative half-cycle, and the ratio of the duration of the positive half-cycle to the duration of the negative half-cycle is equal to the ratio of the amplitude of the positive half-cycle to the amplitude of the negative half-cycle.

9. The method according to claim 4, wherein The backlight controller includes a plurality of driving chips, and each driving chip includes a plurality of output terminals; Based on the dimming mode and the local dimming data, outputting a driving signal to the light-emitting unit group includes: Controlling the driving chips to simultaneously output a plurality of driving signals from the plurality of output terminals, where the periods of the stepped sine waves of the plurality of driving signals are the same, the amplitudes of the positive half-cycles are the same, the amplitudes of the negative half-cycles are the same, and the phases are different from each other; Among them, the phases of the stepped sine waves output from any two output terminals are integer multiples of a reference phase, and the reference phase is the quotient of the period phase divided by the number of output terminals of the driving chip.

10. A backlight controller, characterized in that, The backlight controller is configured to execute the backlight control method according to any one of claims 1 to 9.

11. A display device, characterized in that, It includes the backlight controller according to claim 10.

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