Backlight control method, backlight controller and display equipment

Abstract

The embodiment of the invention provides a backlight control method, a backlight controller and a display device, in 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 step sine wave, and the value of a sampling point on each step in the step sine wave gradually changes according to the fluctuation of a preset sine wave. Because 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 circuit of the power supply unit is reduced, the electromagnetic compatibility of the display equipment is improved, the influence of oscillation of the high-frequency sinusoidal signal in an inductive device of the display equipment on the driving signal is reduced, and the display efficiency is improved. And the stability and the 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 technology, and more particularly to a backlight control method, a backlight controller, and a display device. Background Art

[0002] The 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 outputs the corresponding video image in combination with the backlight provided by the backlight unit.

[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 adjust the brightness of the light-emitting unit group. The pulse width modulation signal is composed of multi-frequency sinusoidal signals superimposed. The presence of a large number of high-frequency sinusoidal signals will introduce harmonic interference into the power supply unit line, affecting the brightness control accuracy 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, which are used to solve the technical problems of harmonic interference of the display device, low regulation accuracy of the luminous 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, wherein the display device includes a backlight unit, wherein the backlight unit includes a backlight controller and a light emitting unit group, and the method is applied to the backlight controller, and the method 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 step sine wave, and a curve constructed by sequentially connecting multiple sampling points in the step sine wave is a preset sine wave. Different effective values ​​of the step sine wave correspond one-to-one to different backlight brightnesses generated by the light-emitting unit group, wherein the multiple sampling points are respectively located at preset positions of multiple steps of the step sine wave.

[0008] In the above technical scheme, 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 line 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.

[0009] Optionally, the multiple steps of the step sine wave have equal widths, and the distances between the sampling points and the end points on the same side of the steps are the same;

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

[0011] In the above technical solution, multiple steps of the step sine wave have equal widths and the sampling points on each step are at the same distance from the endpoints on the same side, which ensures the standardization of the generated step sine wave and makes the step sine wave easy to realize.

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

[0013] 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.

[0014] In the above technical solution, multiple continuous step sine waves are set in one frame display cycle to make the luminous intensity of the light-emitting unit group more uniform, thereby ensuring the display quality of the display device. The periods and waveforms of multiple step sine waves in one frame display cycle are the same, which facilitates the control of 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] Determine a dimming mode based on the configuration information; different configuration information corresponds to different dimming modes one by one;

[0018] Based on the dimming mode and the local dimming data, a driving signal is output to the light emitting unit group.

[0019] In the above technical solution, a variety of optional configuration information is set in the backlight controller, corresponding to a variety of dimming modes, to meet the user's various dimming needs, improve the universality of the backlight control method, and prevent the abnormal display caused by abnormalities in some dimming modes, thereby improving the robustness of the application of this method.

[0020] Optionally, within a 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;

[0021] 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 periodic dimming to perform dimming.

[0022] In the above technical solution, when a plurality of step sine waves fluctuate within a preset range, dimming is performed using a standard sinusoidal dimming mode or a non-standard sinusoidal dimming mode, thereby improving the flexibility of dimming.

[0023] Optionally, 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.

[0024] In the above technical solution, since the preset sine wave corresponding to the step sine wave in the standard sinusoidal dimming mode has the same amplitude and duration in the positive half-axis period and the negative half-axis period, the method of calculating the step sine wave is simpler and convenient for controlling the backlight unit.

[0025] Optionally, 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.

[0026] Optionally, when sinusoidal amplitude dimming is used in the non-standard sinusoidal dimming mode, when the duration of the positive half-cycle and the duration of the negative half-cycle in one cycle of the preset sinusoidal wave are the same, the amplitude of the preset sinusoidal wave in the positive half-cycle is different from the amplitude of the preset sinusoidal wave in the negative half-cycle.

[0027] In the above technical solution, when the sinusoidal amplitude dimming method is used for dimming, the positive half-cycle amplitude and negative half-cycle amplitude of the preset sine wave of the step sine wave can be adjusted separately. When the effective value change amplitude of the step 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.

[0028] Optionally, when dimming is performed using sinusoidal periodic dimming in the non-standard sinusoidal dimming mode, within one cycle of the preset sinusoidal wave, 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.

[0029] In the above technical solution, when the sinusoidal cycle dimming method is used for dimming, the duration of the positive half-cycle and the duration of the negative half-cycle of the step sine wave are adjustable. When the effective value of the step sine wave changes slightly, 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 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, which ensures the smoothness of the waveform change between the positive half-cycle and the negative half-cycle and improves the display effect.

[0030] Optionally, the backlight controller includes a plurality of driver chips, and the driver chip includes a plurality of 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 chip to simultaneously output a plurality of driving signals from the plurality of output terminals, wherein the stepped sinusoidal waves of the plurality of driving signals have the same period, the same amplitude in the positive half period, the same amplitude in the negative half period, and different phases;

[0033] The phase of the step sine waves output by any two output terminals is an integer multiple of a reference phase, and the reference phase is a quotient of the periodic phase divided by the number of output terminals of the driver chip.

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

[0035] In a second aspect, the present application provides a backlight controller, which 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, comprising the backlight controller involved in the second aspect.

[0037] The embodiments of the present application provide a backlight control method, a backlight controller and a display device. When the backlight unit of the display device is emitting light, the waveform of the driving signal output by the backlight controller is a step sine wave. The values ​​of the sampling points on each step in the step 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

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

[0040] Figure 2 A schematic diagram of 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 A schematic flow chart of a backlight control method of a backlight controller provided by the present application according to an exemplary embodiment;

[0042] Figure 4 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 A schematic diagram of a stepped sine wave in the application of a sine amplitude dimming method according to an exemplary embodiment of the present application;

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

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

[0046] Figure 8 The figure is a schematic diagram of the phase relationship of a plurality of stepped sine waves output by a driver chip according to an exemplary embodiment of the present application.

[0047] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope 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 DESCRIPTION

[0048] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, 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 article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including the 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 by their explanation in the specific embodiment or further combined with the context of the specific embodiment.

[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 based on input image data or video data. Figure 1 As shown, 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. 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 arranged on a side of the display surface away from the display panel 20.

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

[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. The backlight controller 301 is electrically connected to the light-emitting unit group 302. The backlight controller 301 obtains local dimming data, outputs a driving signal, and drives 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, and 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 the amplitude of the pulse width modulation signal.

[0055] The pulse width modulation signal is a square wave signal. The generation of the square wave signal is based on the superposition of sine wave signals of multiple frequencies. In some embodiments, the relationship between the pulse width modulation signal in the rising edge level change period and the sine wave signals of multiple frequencies 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, a large amount of high-frequency signals need to be superimposed to modulate the voltage value of the pulse width modulation signal. For example, the high-frequency fluctuation on the pulse width modulation signal in the figure is particularly obvious during the period of sudden level changes. This high-frequency signal is also called high-frequency harmonics. This harmonic will interfere with the power supply line and affect the normal operation of other electronic equipment.

[0056] More specifically, in the circuit structure of the display device, wires and inductive elements are necessary components, wherein the wires include the wiring on the printed circuit board and the wiring between boards, which can also be equivalent to inductive elements. When high-frequency harmonics exist, the high-frequency harmonics will frequently charge and discharge in the inductive elements, generate oscillations, and easily cause noise in the circuit, thereby affecting the accuracy of the output drive signal and the accuracy of regulating the 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 their operation. It will also be affected by external electromagnetic fields, causing signal distortion and affecting the normal and stable operation of display devices.

[0058] The present application provides a backlight control method, a backlight controller and a display device, which are used to solve the technical problems of harmonic interference of the display device, low control accuracy of the luminous brightness and poor electromagnetic compatibility of the display device. The technical concept of the present application is: during the luminescence process of the backlight unit of the display device, the waveform of the driving signal output by the backlight controller is a step sine wave, and the values ​​of the sampling points on each step in the step 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.

[0059] The backlight control method provided by the present application is explained below. Figure 3 FIG. 1 is a flow chart of a backlight control method for a display device provided in accordance with an exemplary embodiment of the present application. Figure 3 As shown, the method includes:

[0060] S101: A backlight controller obtains local dimming data.

[0061] The local dimming data is data generated by the main controller after obtaining the image data or video data, and is used to adjust the luminous brightness of multiple areas in the backlight unit to improve the driving accuracy of the backlight. In some embodiments, the backlight unit includes multiple LEDs, and the local dimming data is data used to control the light emission of the LEDs in each area.

[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 step sine wave. A curve constructed by sequentially connecting multiple sampling points in the step sine wave is a preset sine wave. Different effective values ​​of the step sine wave correspond one-to-one to different backlight brightnesses generated by the light-emitting unit group, wherein the multiple sampling points are respectively located at preset positions of multiple steps of the step 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 adjusts its light brightness based on the current value and current duration of the current signal, wherein 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 step sine wave, that is, the current step value of the current signal changes according to the 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 a plurality of step sampling points 52, and a plurality of sine values ​​determined by the plurality of step sampling points 52 on the preset sine wave are used as the values ​​of the sampling points on the plurality of steps in the step sine wave, and the values ​​can be as follows Figure 4 The sine value corresponding to the earlier step sampling point 52 of the two adjacent points is shown, and the sine value corresponding to the later step sampling point 52 of the two adjacent points can also be shown. The step value change moment is within the time range defined by the two adjacent step sampling points 52. Figure 4 In the figure, the step change time is the time corresponding to the earlier step sampling point 52 between the two adjacent points.

[0065] The step sine wave 51 follows the periodic fluctuation of the preset sine wave 50. In one cycle of the step sine wave 51, the sum of the products of each step value and the corresponding step duration is divided by the cycle length as the effective value of the step 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 light emitting brightness of the light emitting unit group by adjusting the effective value of the step sine wave 51 .

[0067] In the above technical scheme, 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 line 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 step sine wave 51 are of equal width, and the distances between each step sampling point 52 and the end points on the same side of the steps are the same, that is, each step sampling point 52 samples the preset sine wave 50 at the same time interval, and uses the sampling value as the value of the step, the duration of each step is the same, and the distance between each step sampling point 52 and the change point on the left side of the step is the same, that is, the distance between each step sampling point 52 and the change point on the right side of the step is the same, which is convenient for unified control. At this time, the effective value of the step sine wave 51 is the average of the values ​​of the sampling points of multiple steps of the step sine wave 51 in one cycle.

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

[0070] In some embodiments, a frame display cycle includes a plurality of continuous step sine waves 51. In a frame display cycle, the periods of the plurality of step sine waves are the same, and the waveforms of the plurality of step sine waves are the same. For example, the current frame display cycle (the first frame display cycle) includes 50 continuous step sine waves 51, and the waveform changes of the 50 step sine waves 51 are the same, that is, the period and amplitude changes are the same. When entering the next frame display cycle (the second frame display cycle), the next frame display cycle may still include 50 continuous step sine waves 51, but the amplitude change is irrelevant to the amplitude change of the step sine wave 51 in the first frame display cycle and may be different; it may also include 60 continuous step sine waves 51 when entering the next frame display cycle (the second frame display cycle), and it is only necessary to ensure that the plurality of step sine waves in the second frame display cycle fluctuate according to the period.

[0071] In the above technical solution, multiple continuous step sine waves are set in one frame display cycle to make the luminous intensity of the light-emitting unit group more uniform, thereby ensuring the display quality of the display device. The periods and waveforms of multiple step sine waves in one frame display cycle are the same, which facilitates the control of the backlight unit group.

[0072] In some embodiments, the backlight controller includes configuration information, and 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. The configuration information may be information pre-set in the backlight controller 310, or may be data pre-stored in the main controller 10 and transmitted simultaneously when the main controller 10 transmits the local dimming data, or may be configuration information written into the main controller 10 by the user through the input device of the display device. Different configuration information corresponds to different dimming modes one by one. In 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, a variety of optional configuration information is set in the backlight controller, corresponding to a variety of dimming modes, to meet the user's various dimming needs, improve the universality of the backlight control method, and prevent the abnormal display caused by abnormalities in some dimming modes, thereby improving the robustness of the application of this method.

[0075] The following explains the various dimming modes that can be set by the backlight controller 310 and the waveform of the output driving signal in each dimming mode.

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

[0077] In one frame display period, the preset sine waves 50 corresponding to the multiple step 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 preset range is the fluctuation range that the value of the step sine wave 51 cannot exceed.

[0078] The period of the preset sine wave 50 is the same as the period of the step sine wave 51. One period T of the preset sine wave 50 includes a positive half-period T1 and a negative half-period T2. In the positive half-period T1, the preset sine wave 50 is located on the upper side of the preset horizontal axis 53. In the negative half-period T2, the preset sine wave 50 is located on the lower side of the preset horizontal axis 53.

[0079] In the standard sinusoidal dimming mode, within a cycle T of the preset sine wave 50, the duration of the positive half cycle T1 is the same as the duration of the negative half cycle T1, and the amplitude of the preset sine wave 50 within the positive half cycle T1 is the same as the amplitude of the preset sine wave 50 within the negative half cycle T2. Among them, the amplitude of the preset sine wave 50 in the positive half cycle T1 is the difference between the maximum value of the preset sine wave 50 in the positive half cycle T1 and the corresponding value of the preset horizontal axis 53, and the amplitude of the preset sine wave 50 in the negative half cycle T2 is the absolute value of the difference between the minimum value of the preset sine wave 52 in the negative half cycle T2 and the corresponding value of the preset horizontal axis 53. Figure 4 In the waveform diagram shown, the amplitude of the preset sine wave 50 in the positive half cycle T1 and the negative half cycle T2 is 1, and the effective value of the step 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 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.

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

[0082] In some embodiments, the dimming mode includes a non-standard sinusoidal dimming mode, and the non-standard sinusoidal dimming mode uses sinusoidal amplitude dimming or sinusoidal periodic dimming to perform dimming.

[0083] When the non-standard sinusoidal dimming mode is dimmed by sinusoidal amplitude dimming, the waveform diagram of the step sine wave 51 output by the backlight controller 310 and the corresponding preset sine wave 50 can be referred to Figure 5 shown.

[0084] and Figure 4 The waveforms shown are similar. In one frame display period, the preset sine wave 50 corresponding to the multiple step sine waves 51 fluctuates 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. In the positive half period T1, the preset sine wave 50 is located on the upper side of the preset horizontal axis 53, and in the negative half period T2, the preset sine wave 50 is located on the lower side of the preset horizontal axis 53.

[0085] When the sine amplitude dimming method is used for dimming, within a period T of the preset sine wave 50, when the duration of the positive half period T1 is the same as the duration of the negative half period T2, Figure 4 The difference between the waveforms shown is that the amplitude of the preset sine wave 50 in the positive half cycle T1 is different from the amplitude of the preset sine wave 50 in the negative half cycle T2.

[0086] In some embodiments, for a step sine wave 51 that fluctuates around the same preset horizontal axis, the amplitude of the preset sine wave 50 corresponding to the step sine wave 51 in the positive half cycle T1 is positively correlated with the effective value of the step sine wave 51, and the amplitude of the preset sine wave 50 corresponding to the step sine wave 51 in the negative half cycle T2 is negatively correlated with the effective value of the step sine wave 51. Specifically, the greater the amplitude of the preset sine wave 50 corresponding to the step sine wave 51 in the positive half cycle T1, the greater the effective value of the step sine wave 51; the greater the amplitude of the preset sine wave 50 corresponding to the step sine wave 51 in the negative half cycle T2, the smaller the effective value of the step sine wave 51.

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

[0088] In some other embodiments, when the stepped sine wave output by the backlight controller 301 is as follows: Figure 4When the standard stepped sine wave is shown, when the effective value is increased according to the standard sinusoidal 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 the curve is adjusted according to the sinusoidal amplitude dimming method, the amplitude of the negative half-cycle T2 can be reduced first to increase the effective value. When the step of adjusting the negative half-cycle T2 cannot achieve the target effective value or the effect is not good (such as: the curve connection effect of the preset sine wave 50 of the positive half-cycle T1 and the negative half-cycle T2 is poor), the value of the preset horizontal axis 53 is moved upward to improve the adjustment accuracy of the effective value.

[0089] In the above technical solution, when the sinusoidal amplitude dimming method is used for dimming, the positive half-cycle amplitude and negative half-cycle amplitude of the preset sine wave of the step sine wave can be adjusted separately. When the effective value change amplitude of the step 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 the sinusoidal periodic dimming method is adopted in the non-standard sinusoidal dimming mode, the waveform diagram of the step sine wave 51 output by the backlight controller 310 and the corresponding preset sine wave 50 can be referred to as Figure 6 shown.

[0091] and Figure 4 , Figure 5 The waveforms shown are similar. In one frame display period, the preset sine waves 50 corresponding to the multiple step 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 period T1 and a negative half period T2. In the positive half period T1, the preset sine wave 50 is located above the preset horizontal axis 53, and in the negative half period T2, the preset sine wave 50 is located below the preset horizontal axis 53.

[0093] and Figure 4 , Figure 5 The difference between the waveforms shown is that, when the sinusoidal period dimming method is adopted, within one cycle of the preset sinusoidal wave 50, the duration of the positive half-period T1 is different from the duration of the negative half-period T2, and the ratio of the duration of the positive half-period T1 to the duration of the negative half-period T2 is equal to the ratio of the amplitude of the positive half-period T1 to the amplitude of the negative half-period T2, so that the preset sinusoidal wave 50 can smoothly connect from the curve of the positive half-period T1 to the curve of the lower half-period T2.

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

[0095] In the above technical solution, when the sinusoidal periodic dimming method is adopted, the duration of the positive half-cycle and the duration of the negative half-cycle of the step sine wave are adjustable. When the effective value of the step sine wave changes slightly, 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 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, which ensures the smoothness of the waveform change between the positive half-cycle and the negative half-cycle and improves the display effect.

[0096] When the sinusoidal amplitude dimming method and the sinusoidal period dimming method are used in the non-standard sinusoidal dimming mode, dimming can be performed in a preset order. For example, dimming is performed by first using the sinusoidal amplitude dimming method and then by using the sinusoidal period dimming method, which is not limited here. The following is explained in the order of sinusoidal amplitude dimming first and then sinusoidal period dimming. If the waveform of the positive half-cycle remains unchanged, when adjusting the waveform of the negative half-cycle 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 transform the period and amplitude of 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, so as to further improve the adjustment accuracy.

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

[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 image quality; in some embodiments, the dimming controller 3011 can map and output the local dimming data with the corresponding electrically connected multiple driver chips 3012; in some embodiments, the dimming controller 3011 can perform protocol conversion on the local dimming data obtained and then output it.

[0099] The driver chip 3012 outputs a driving signal based on the processed local dimming data to drive the light emitting unit group 302 to emit light.

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

[0101] The backlight controller 301 controls the driver chip 3012 to simultaneously output multiple drive signals from multiple output terminals, the stepped sine waves of the multiple drive signals have the same period, the same amplitude of the positive half period, the same amplitude of the negative half period, and different phases; wherein 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 driver chip.

[0102] Combine the following Figure 8 The waveform diagram shown is used for explanation. The phase of one cycle of the step sine wave is 2π. When each output terminal of the driver chip 3012 outputs a driving signal, the cycle and waveform of the step sine wave are the same, but there is a phase deviation. The number N of output terminals of the driver chip 3012 is used to divide 2π equally, and N phase values ​​are determined from [0, 2π):

[0103] 0. , ,……, .

[0104] And correspondingly allocated to N output terminals as the phase of the output terminal. Figure 8 As shown in the waveform diagram, the driver chip 3012 is provided with 4 output terminals, and the cycle phase is divided into 4 parts, and the phases of the signals output from the output terminals are sequentially spaced 90° apart, and the reference phase is 90°, and the phase of each step sine wave is 0 to 3 times the reference phase.

[0105] In the above technical solution, in the backlight controller, when the multiple output ends of the driver chip drive the multiple light-emitting unit groups to emit light, the phases of the drive signals output by the multiple output ends are evenly staggered, so that the total value of the drive signal output by the driver chip fluctuates little, which can reduce the interference between adjacent output ends and further improve electromagnetic compatibility.

[0106] In some embodiments, the present application provides a backlight controller 301, which is used to execute the backlight control method in the aforementioned embodiments, which will not be described in detail here.

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

[0108] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0109] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only 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, and 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 step sine wave, and a curve constructed by sequentially connecting multiple sampling points in the step sine wave is a preset sine wave. Different effective values ​​of the step sine wave correspond one-to-one to different backlight brightnesses generated by the light-emitting unit group, wherein the multiple sampling points are respectively located at preset positions of multiple steps of the step sine wave.

2. The method according to claim 1, characterized in that The multiple steps of the step sine wave have equal widths, and the distances between the sampling points and the end points on the same side of the steps are the same; The effective value of the step sine wave is the average of the values ​​of the sampling points on multiple steps in one cycle of the step sine wave.

3. The method according to claim 2, characterized in that One frame display cycle includes a plurality of 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 The backlight controller includes configuration information; Outputting a driving signal to the light emitting unit group based on the local dimming data includes: Determine a dimming mode based on the configuration information; different configuration information corresponds to different dimming modes one by one; 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 4, characterized in that 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; 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 periodic dimming to perform dimming.

6. The method according to claim 5, characterized in that 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.

7. The method according to claim 6, 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.

8. The method according to claim 5, characterized in that When dimming is performed using sinusoidal amplitude dimming in the non-standard sinusoidal dimming mode, when the duration of the positive half-cycle and the duration of the negative half-cycle in one cycle of the preset sinusoidal wave are the same, the amplitude of the preset sinusoidal wave in the positive half-cycle is different from the amplitude of the preset sinusoidal wave in the negative half-cycle.

9. The method according to claim 5, characterized in that When dimming is performed using sinusoidal periodic dimming in the non-standard sinusoidal dimming mode, 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.

10. The method according to claim 4, characterized in that The backlight controller includes a plurality of driver chips, and the driver chips include 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 chip to simultaneously output a plurality of driving signals from the plurality of output terminals, wherein the stepped sinusoidal waves of the plurality of driving signals have the same period, the same amplitude in the positive half period, the same amplitude in the negative half period, and different phases; The phase of the step sine waves output by any two output terminals is an integer multiple of a reference phase, and the reference phase is a quotient of the periodic phase divided by the number of output terminals of the driver chip.

11. A backlight controller, characterized in that: The backlight controller is used to execute the backlight control method as described in any one of claims 1 to 10.

12. A display device, characterized in that: Comprising the backlight controller as claimed in claim 11.

Images