CN108780627B

CN108780627B - Backlight power control method of liquid crystal display screen and liquid crystal display screen

Info

Publication number: CN108780627B
Application number: CN201780013528.4A
Authority: CN
Inventors: 罗诚; 韦育伦; 王妙锋; 王苗苗; 禹秀泳
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-06-26
Filing date: 2017-06-26
Publication date: 2020-11-27
Anticipated expiration: 2037-06-26
Also published as: WO2019000157A1; CN108780627A

Abstract

A backlight power control method of a liquid crystal display screen and the liquid crystal display screen are provided. The method comprises the steps that an LCD acquires an LED pulse width modulation signal of the LCD; the LCD adopts a Content Adaptive Backlight Control (CABC) algorithm to determine the backlight reduction ratio; the LCD adjusts at least one of an amplitude or a pulse width of the LED pulse width modulation signal according to the backlight reduction ratio; and the LED backlight light source in the LCD emits backlight according to the adjusted LED pulse width modulation signal. At least one of the width or the amplitude of the LED pulse width modulation signal is adjusted according to the calculated backlight reduction ratio, so that the purpose of reducing the backlight power consumption under the same display effect is achieved.

Description

Backlight power control method of liquid crystal display screen and liquid crystal display screen

Technical Field

The application relates to the technical field of liquid crystal display screens, in particular to a backlight power control method of a liquid crystal display screen and the liquid crystal display screen.

Background

A Liquid Crystal Display (LCD) is formed by placing a Liquid Crystal layer between two parallel glass substrates, a Thin Film Transistor (TFT) is disposed on the lower substrate glass, and a color filter is disposed on the upper substrate glass, and the rotation direction of Liquid Crystal molecules is controlled by changing the signal and voltage on the TFT, so as to control whether polarized light of each pixel point is emitted, thereby displaying different colors.

Because the LCD does not emit light, that is, a user needs to see the display content on the LCD and provide a backlight source on the back of the LCD, there are two types of backlight sources of the current common LCD, one is to use a Cold Cathode Fluorescent Lamp (CCFL) as the backlight source, and the CCFL has the advantages of good color performance and high power consumption; the other is to use a Light Emitting Diode (LED) as a backlight source, and the LED has the advantages of small size and low power consumption, so that the LED is used as a backlight source, and can achieve higher brightness while achieving Light and thin properties. However, with the development of LED technology, the difference is shrinking, and in view of the higher requirement of the current mobile terminal device for the device endurance time, most of the mobile terminal devices employ LED light sources.

In addition, for the LCD, as the display principle of the LCD is that the penetration rate of a liquid crystal layer is changed to reach different gray-scale pixels by changing the driving voltage, namely, a certain time is needed for converting one gray scale into an adjacent gray scale, and the gray scale conversion time for measuring one LCD is the conversion time of the slowest order of the LCD, the conversion reaction time of the slowest order of the traditional LCD can be as high as 30-40 milliseconds, so that the effect that the object which is displayed to move fast has obvious smear is achieved; the conversion reaction time of the slowest order of the fast LCD can be reduced to 5-6 milliseconds, and the smear can be effectively reduced by changing the normally bright display into the impulse display by matching with the backlight black insertion technology.

However, since the liquid crystal layer transmittance of the fast LCD is lower than that of the conventional LCD, the power consumption of the backlight light source must be increased to achieve the display luminance of the conventional LCD.

Disclosure of Invention

The embodiment of the application provides a backlight power control method of a liquid crystal display and the liquid crystal display to solve the problem of high backlight consumption of the conventional fast LCD.

A first aspect of the embodiments of the present application provides a backlight power Control method for a liquid crystal display, in which an LCD first obtains an LED pulse width modulation signal of the LCD, then performs Content Adaptive backlight Control (cabac) processing on Content to be displayed corresponding to the LED pulse width modulation signal to obtain a backlight reduction ratio of the backlight of the Content to be displayed, and then adjusts at least one of an amplitude or a pulse width of the LED pulse width modulation signal according to the backlight reduction ratio, so that a product of the pulse width and the amplitude of the adjusted LED pulse width modulation signal is the backlight reduction ratio of the product of the pulse width and the amplitude of the LED pulse width modulation signal before adjustment; and finally, the LED backlight light source can emit backlight according to the adjusted LED pulse width modulation signal, namely, the LED backlight light source emits light according to the pulse width and the amplitude of the LED pulse width modulation signal.

It can be seen that, since at least one of the width or the amplitude of the LED pwm signal is adjusted according to the calculated backlight reduction ratio before the LED pwm signal is emitted, and the reduction of the backlight ratio will reduce the power consumption, the power consumption of the LED backlight light source emitting light according to the adjusted LED pwm signal is lower than the power consumption of the LED backlight light source emitting light according to the LED pwm signal before the adjustment, thereby achieving the purpose of reducing the backlight power consumption in the same display effect.

In some embodiments, before adjusting at least one of the amplitude or the pulse width of the LED pwm signal according to the backlight reduction ratio, a preset pulse width and a preset amplitude corresponding to the backlight reduction ratio are obtained. The preset pulse width is a backlight reduction ratio of the pulse width of the LED pulse width modulation signal corresponding to the content to be displayed, and the preset amplitude is the backlight reduction ratio of the amplitude of the LED pulse width modulation signal corresponding to the content to be displayed. The preset pulse width and the preset amplitude are set according to the backlight reduction ratio, so that at least one of the pulse width and the amplitude can be used as an adjustment reference value when being adjusted, and the adjustment is more convenient.

In some embodiments, one of the pulse width and amplitude is adjusted by adjusting the pulse width or amplitude of the LED pulse width modulation signal according to the backlight reduction ratio. The pulse width adjustment may specifically be to shorten a pulse width of the LED pulse width modulation signal to a preset pulse width according to the backlight reduction ratio; the amplitude adjustment may specifically be to reduce the amplitude of the LED pwm signal to a preset amplitude according to the backlight reduction ratio. It can be seen that when one of the pulse width and the amplitude is adjusted, only the corresponding preset pulse width or amplitude needs to be adjusted directly. The method can realize quick adjustment and enhance the realizability of the display backlight power control method.

In some embodiments, there is another way to adjust only the pulse width, that is, adjust the pulse width in the LED pulse width modulation signal to at least two sub-pulse widths with intervals according to the backlight reduction ratio, and the sum of the pulse widths of the at least two sub-pulse widths is the preset pulse width. In this manner, the high-frequency pulse is used to replace the original pulse of the LED pwm signal, so that one pulse of the LED pwm signal is changed into a plurality of sub-pulses, but the sum of the pulse widths of the sub-pulses is the predetermined pulse width, and the backlight reduction ratio in which the product of the pulse width and the amplitude of the adjusted LED pwm signal is the product of the pulse width and the amplitude of the LED pwm signal before adjustment can be achieved.

In some embodiments, the adjusting of the pulse width and the amplitude simultaneously may be to shorten the pulse width of the LED pwm signal to be greater than the preset pulse width and to reduce the amplitude of the LED pwm signal to be greater than the preset amplitude according to the backlight reduction ratio. That is, in this manner, the values of the pulse width and the amplitude are made smaller at the same time, so that the backlight reduction ratio is achieved in which the product of the adjusted pulse width and amplitude is the product of the pulse width and amplitude before adjustment. The realizability of the display backlight power control method is enhanced.

In some embodiments, the adjusting of the pulse width and the amplitude simultaneously may further be to shorten the pulse width of the LED pwm signal to be smaller than the preset pulse width and increase the amplitude of the LED pwm signal according to the backlight reduction ratio. In this manner, the pulse width is adjusted to be smaller than the preset pulse width, and in order to make the product of the adjusted pulse width and the amplitude be the backlight reduction ratio of the product of the pulse width and the amplitude before adjustment, the amplitude needs to be increased. The realizability of the display backlight power control method can be enhanced.

In some embodiments, the adjusting of the pulse width and the amplitude simultaneously may further be that the amplitude value of the LED pwm signal is decreased to be smaller than the preset amplitude value according to the backlight reduction ratio, and the pulse width of the LED pwm signal is increased. In this manner, the amplitude is adjusted to be smaller than the preset amplitude, and in order to make the product of the adjusted pulse width and the amplitude be the backlight reduction ratio of the product of the pulse width and the amplitude before adjustment, the pulse width needs to be increased. The realizability of the display backlight power control method can be enhanced.

A second aspect of the embodiments of the present application further provides a liquid crystal display, which includes an LCD panel, an LCD driver Integrated Circuit (IC) electrically connected to the LCD panel for driving the LCD panel, an LED backlight source further disposed on a back surface of the LCD panel, an LED driver IC for driving the LED backlight source further connected to the LED backlight source, the LCD driver IC further connected to the LED driver IC, wherein,

the LCD driving IC is used for acquiring an LED pulse width modulation signal of the LCD;

the LCD driving IC is also used for determining a backlight reduction proportion by adopting a content corresponding backlight control CABC algorithm, wherein the backlight reduction proportion is the backlight reduction proportion of the content to be displayed corresponding to the LED pulse width modulation signal;

the LCD driving IC is further used for adjusting at least one of the amplitude or the pulse width of the LED pulse width modulation signal according to the backlight reduction proportion, wherein the product of the pulse width and the amplitude of the adjusted LED pulse width modulation signal is the backlight reduction proportion of the product of the pulse width and the amplitude of the LED pulse width modulation signal before adjustment;

the LED driving IC is used for driving the LED backlight light source to emit backlight according to the adjusted LED pulse width modulation signal;

the LCD panel is used for displaying the content to be displayed.

In some embodiments, the LCD driver IC is further configured to obtain a preset pulse width and a preset amplitude, where the preset pulse width and the preset amplitude correspond to a backlight reduction ratio of the content to be displayed; the preset pulse width is the backlight reduction proportion of the pulse width of the LED pulse width modulation signal corresponding to the content to be displayed; the preset amplitude is a backlight reduction ratio of the amplitude of the LED pulse width modulation signal corresponding to the content to be displayed.

In some embodiments, the LCD driver IC is specifically configured to: shortening the pulse width of the LED pulse width modulation signal to a preset pulse width according to the backlight reduction proportion; or the amplitude of the LED pulse width modulation signal is reduced to a preset amplitude according to the backlight reduction proportion.

In some embodiments, the LCD driver IC is specifically configured to adjust the pulse width of the LED pwm signal to at least two sub-pulse widths with intervals, wherein the sum of the pulse widths of the at least two sub-pulse widths is the preset pulse width according to the backlight reduction ratio.

In some embodiments, the LCD driver IC is specifically configured to shorten a pulse width of the LED pwm signal to be greater than the preset pulse width and to reduce an amplitude of the LED pwm signal to be greater than the preset amplitude according to the backlight reduction ratio.

In some embodiments, the LCD driver IC is specifically configured to shorten a pulse width of the LED pwm signal to be less than the preset pulse width and increase an amplitude of the LED pwm signal according to the backlight reduction ratio.

In some embodiments, the LCD driver IC is specifically configured to decrease the amplitude value of the LED pwm signal to be smaller than the preset amplitude value and increase the pulse width of the LED pwm signal according to the backlight reduction ratio.

Yet another aspect of the present application provides a computer-readable storage medium having stored therein instructions, which when executed on a computer, cause the computer to perform the method of the above-described aspects.

Yet another aspect of the present application provides a computer program product containing instructions which, when run on a computer, cause the computer to perform the method of the above-described aspects.

Drawings

FIG. 1 is a schematic diagram of a VR display system;

FIG. 2 is a schematic diagram of gray scale conversion in a liquid crystal display;

FIG. 3 is a schematic diagram of a fast response LCD using black insertion for conventional LCDs and VRs to display high speed moving pictures;

FIG. 4 is a schematic diagram of a fast response LCD using black insertion;

FIG. 5a is a schematic diagram of a normally bright display without black insertion;

FIG. 5b is a schematic diagram of a display with black inserted pulses;

FIG. 6 is a schematic diagram of an LCD panel according to an embodiment of the present application;

FIG. 7 is a schematic diagram of an LCD panel according to an embodiment of the present application;

FIG. 8 is a diagram of an embodiment of a method for controlling backlight power of a liquid crystal display panel according to an embodiment of the present application;

FIG. 9 is a schematic diagram of dynamic backlight adjustment of display content using CABC;

fig. 10 is a diagram of an embodiment of a backlight power control method of a liquid crystal display panel according to an embodiment of the present application;

fig. 11 is a diagram of an embodiment of a backlight power control method of a liquid crystal display panel according to an embodiment of the present application;

fig. 12 is a diagram of an embodiment of a backlight power control method of a liquid crystal display panel according to an embodiment of the present application;

fig. 13 is a diagram of an embodiment of a method for controlling backlight power of a liquid crystal display panel according to an embodiment of the present application.

Detailed Description

In order to make the technical field better understand the scheme of the present application, the following description will be made on the embodiments of the present application with reference to the attached drawings.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims of the present application and in the drawings described above, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein. Furthermore, the terms "comprises," "comprising," or "having," and any variations thereof, are intended to cover non-exclusive inclusions, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

In the field of Virtual Reality (VR), a head display mode is mainly adopted at present, that is, one or two display screens are arranged in one head display to respectively display two different images to two eyes, the two different images are driven by a display chip of the display screen, the two images have slight difference, the difference is similar to binocular parallax of a human, an enlarged Virtual image is generated between a human eye and the display screen through one lens to simulate, so as to generate immersion feeling of the real world, specifically, referring to fig. 1, fig. 1 is a schematic diagram of a VR display system, a distance between a human eye 101 and an eyepiece 102 is L1, a distance between the eyepiece 102 and a display screen 103 is L2, a distance between the human eye 101 and a Virtual image plane 104 is L3, namely, a picture generated at a distance L3 in front of the human eye 101 is sensed, wherein the eyepiece 102 can be a fresnel lens, also known as a screw lens, the lens is mainly a thin sheet formed by injecting and pressing polyolefin materials and is also made of glass, one surface of the lens is a smooth surface, the other surface of the lens is inscribed with concentric circles from small to large, the texture of the lens is designed according to the requirements of light interference and interference, relative sensitivity and receiving angle, and the phenomena that the corners of a common convex lens are darkened and blurred can be solved.

When the head of a human body wearing the VR head display moves towards different directions, the display screen can display images of changes in the moving process, for example, when the head moves leftwards, the display screen can display a visual picture change which is seen by animation simulation human eyes from left to right in the real world. However, because the frame is moving or even moving at a high speed, when such content is displayed on a conventional LCD, the frame has a serious smear, which may cause a user using VR to feel dizzy and nausea, so the VR head generally uses a fast-response LCD with a backlight black-insertion technology, and the slowest-order transition response event is 5-6 ms. As shown in fig. 2, fig. 2 is a schematic diagram of gray scale conversion in a liquid crystal display panel, wherein the abscissa is time and the ordinate is gray scale percentage, i.e. if gray scale is 256 levels from black to white, black is at 0% position and white is at 100% position. The curve in the figure represents the process of converting the liquid crystal from the gray level N to the gray level M and then from the gray level M to the gray level N, the gray level N is represented by Gray (N) in figure 2, the gray level M is represented by Gray (M) in figure 2, wherein N is smaller than M, N and M are the first order of 256 gray levels, Tr is the reaction time from the gray level N to the gray level M, and Tf is the reaction time from the gray level M to the gray level N.

As shown in fig. 3, which is a schematic view of a fast response LCD using a black insertion technique for a conventional LCD and VR displaying a high-speed moving picture, it can be seen that the smear of the conventional LCD is severe, and the smear of the fast response LCD using the black insertion technique is almost none. Specifically, fig. 4, fig. 5a and fig. 5b show that the fast response LCD uses the black insertion technique, and fig. 4 a shows a schematic diagram of the normally bright display without black insertion; FIG. 5b is a schematic diagram of a display with black inserted pulses; in fig. 4, the P1 phase represents the backlight off phase, the P2 phase represents the backlight on phase, and the S1 phase of the P1 phase is the data scanning phase, in which the gray level voltage to be displayed for each pixel is determined; the S2 stage of the P1 stages is a liquid crystal response operation section after completion of data scanning; in this section, the liquid crystal is rotated to a corresponding angle according to the gray scale voltage to be displayed by each pixel in the data scanning stage. After the two-part operation is completed, the stage P2 can be executed to turn on the backlight for displaying; the P1 and P2 phases indicate the duration of one frame, and it can be seen that each frame includes a backlight off section and a backlight on section, and Vsync indicates the synchronization of each frame, for example, the length of the backlight on section is one tenth of the frame display time.

It can be seen that in practice, the data scanning phase and the liquid crystal response phase are parts that are not needed to be seen by a user, that is, the parts can be performed without turning on the backlight, and the black insertion technology is performed by adopting the characteristic.

In fig. 5a and 5b, each small square indicates one pixel, fig. 5a is a display mode without black insertion, fig. 5b is a display mode with 50% black insertion, and comparing fig. 5a and 5b, it can be seen that in the case of the same frame, the smear length for the normally bright display without black insertion is 4 pixels, and the smear length for the impulse display mode with 50% black insertion is only 2 pixels.

In addition, for the conventional LCD, the backlight power consumption of the LCD is reduced, and two modes, namely, Light Adaptive Backlight Control (LABC) and CABC, are also used, and the Brightness adaptation is usually used to adapt to the ambient Light, which is basically not used in the case of VR system.

Among them, the cabac dynamic backlight adjustment adjusts the backlight according to the content of a specific display. The backlight brightness is reduced by analyzing the content to be displayed, and meanwhile, in order to ensure that the displayed content is basically the same as the effect before CABC adjustment is not performed, the transmittance of gray scales in the content needs to be adjusted to perform brightness compensation. For the liquid crystal display, the display brightness of the liquid crystal display sensed by human eyes is obtained by multiplying the luminous brightness of the LED backlight light source by the penetration rate of the gray scale. Wherein, the transmittance of a certain level of gray scale is the voltage corresponding to the level of gray scale.

For example, the brightness of the LED backlight source is 1000 units, the transmittance of the X-level gray scale is 60%, the value of X is between 0 and 255, and the display brightness of the final lcd panel is 600 units. If it is found by the CABC calculation that the backlight can be reduced to 80%, i.e. the backlight becomes 800 units, and in order to make the final display brightness still 600 units, the transmittance of the X-level gray scale needs to be adjusted, for example, the transmittance is adjusted to 75% (actually, the voltage is adjusted), and the final display brightness of the liquid crystal display panel is 800 units multiplied by 75%, still 600 units. Therefore, the light emitting brightness of the LED backlight light source is reduced under the condition of not losing the display brightness.

When the CABC is used, a function of content analysis needs to be added to the LCD driver IC, and the addition of the function can be realized by software or by adding a specific content analysis circuit to the LCD driver IC. The specific working process of CABC is as follows:

first, the application processor sends content to be displayed (e.g., picture data) to the LCD driver IC, the picture data is analyzed by the content analysis function, and the backlight reduction ratio is determined according to a certain rule. The rule analyzes, for example, that if the ratio of dark or black portions in the picture data exceeds a certain ratio, the backlight reduction ratio is set to a fixed value; of course, the rule may be preset when designing a content analysis function or a circuit, and in addition, the LCD driver IC further stores a correspondence relationship between a backlight reduction ratio and a transmittance adjustment of a gray scale. And finally, the LCD driving IC drives the LCD panel to display the content to be displayed according to the penetration rate of the adjusted gray scale, and the backlight light source of the LCD is driven by the LCD driving IC to reduce the backlight brightness according to the backlight reduction ratio, so that the effect of the finally displayed picture is basically the same as that of the picture before CABC. And since the brightness of the backlight light source is reduced, the power consumption can be reduced. Therefore, this CABC technique is suitable for use on mobile devices that employ batteries as a power source.

Because the backlight power consumption of the fast-response liquid crystal display is determined to be higher due to the characteristics of the fast-response liquid crystal display, in order to solve the problem, the embodiment of the application provides a backlight power control method of the fast-response liquid crystal display, namely the liquid crystal display, to solve the problem that the backlight power consumption is higher. First, a structure of the lcd panel of the present application will be described, please refer to fig. 6, where fig. 6 is a schematic diagram of a structure of the lcd panel according to an embodiment of the present application. The liquid crystal display screen comprises an LCD panel and an LED backlight light source arranged on the back of the LCD panel, wherein the LCD panel is connected with an LCD driving IC, the LED backlight light source is connected with an LED driving IC for driving the LED backlight light source, and the LCD driving IC is also connected to the LED driving IC. The specific working process of the liquid crystal display screen can be that the LCD driving IC receives contents to be displayed, the LCD driving IC generates a PWM signal and then sends the PWM signal to the LED driving IC, and the LED driving IC drives the LED to emit light according to the PWM signal.

It should be noted that the LED driving IC and the LCD driving IC may be disposed on different functional modules, specifically, refer to fig. 7, and fig. 7 is a schematic structural diagram of a display screen of the liquid crystal display panel according to an embodiment of the present application, in which an MPU or a CPU and the LED driving IC are disposed on a main board portion, the LED driving IC may be a WLED (white LED) driving IC, and the LCD module is disposed with an LCD panel, an LCD driving IC and a plurality of LEDs disposed on a back surface of the LCD panel, and of course, the LEDs may also be a WLED. The specific working process can be that the MPU or the CPU sends the content to be displayed to the LCD drive IC, then the LCD drive IC generates a PWM signal on one hand and sends the PWM signal to the LED drive IC, on the other hand, the LCD drive IC also outputs the PWM signal to the LCD panel according to the content to be displayed, and then the LED drive IC simultaneously adjusts the current input to the LED after receiving the PWM signal, so that the LED emits light.

Next, regarding the backlight power control method of the liquid crystal display panel according to the embodiment of the present application, the backlight power control method of the liquid crystal display panel according to the embodiment of the present application can be applied to the liquid crystal display panel architecture shown in fig. 6 or fig. 7. The method for controlling the backlight power of the liquid crystal display panel according to the embodiment of the present application will be described below by taking the structure shown in fig. 6 as an example. Referring to fig. 8, fig. 8 is a diagram illustrating an embodiment of a method for controlling backlight power of a liquid crystal display panel according to an embodiment of the present disclosure, the method may include:

801. the LCD driving IC obtains an LED pulse width modulation signal of the LCD.

The liquid crystal display screen adopts a black insertion technology, so that an LED signal output to an LED backlight light source is an LED pulse width modulation signal, and the pulse width of the pulse width modulation signal is the backlight starting time in the time of one frame.

PWM controls the on-off of the switching element of the inverter circuit, so that the output end obtains a series of pulse control modes with equal amplitude. If the width of each pulse of the PWM signal is modulated according to a certain rule without changing the amplitude, that is, the magnitude of the output voltage of the inverter circuit can be changed by adjusting the duty ratio of the pulse, and of course, the output frequency of the PWM signal can be changed by adjusting the pulse width.

The LED dimming method adopting the PWM technology is characterized in that the on-time of forward current is changed by periodically turning on and off the LED to control the bright and dark time of the LED; since the brightness perceived by human eyes is an accumulative process, that is, the greater the proportion of the whole period of the LED on in one period, the brighter the human eyes can perceive. If the frequency of brightness and darkness of the LED exceeds 100Hz, the average brightness is seen by human eyes, but the LED is not flickering, and under the condition that the amplitude is unchanged, when the pulse width is adjusted, the brightness is increased by increasing the pulse width, and otherwise, the brightness is reduced. The working frequency of an LED backlight light source of the liquid crystal display screen adopting PWM dimming is generally about 200Hz-1000Hz, and due to the fact that the nature of PWM light emission is a process of 'on-off-on-off', the process is equivalent to that visible light carries out flicker impact with certain frequency on human eyes, and when the PWM frequency is higher, namely the flicker frequency is higher, the perception of the human eyes on the impact is weaker; while the higher the brightness, the less the human eye perceives this flickering impact.

Therefore, the PWM dimming manner is different from the linear dimming manner in which the brightness of the LED is changed by changing the current level of the LED, and the PWM dimming only causes the LED to operate discontinuously, so that the brightness of the LED can be changed without changing the current level.

It should be noted that, for example, the duration of one frame of the LCD is different due to the difference of the refresh rate, and the refresh rate of the LCD is set to 60hz, which indicates that the image displayed on the LCD is redrawn 60 times per second, and the duration of one frame at this time is 1/60 seconds, and similarly, if the refresh rate of the LCD is 90hz, which indicates that the image displayed on the LCD is redrawn 90 times per second, and the duration of one frame at this time is 1/90 seconds. Of course, for the VR domain, the higher the refresh rate, the better, and in the case of a low refresh rate, the picture seen by 60hz will have a noticeable unstable flicker, which, in addition to the scene moving with the viewing angle, will have symptoms such as eye discomfort and dizziness. For the LCD in the embodiment of the present application, the refresh rate may be more than 90hz, which is effective in reducing the above symptoms.

802. The LCD driver IC determines the backlight reduction ratio using the CABC algorithm.

For example, please refer to fig. 9, where fig. 9 is a schematic diagram illustrating a display content adjusted by a dynamic cabac backlight, in which the backlight reduction ratio is a backlight reduction ratio of a content to be displayed corresponding to the LED pwm signal, and the cabac technology can adjust the backlight reduction ratio in real time according to the content to be displayed. The first image 901 is an original image, the second image 903 is a content analysis result, and then the backlight brightness can be reduced by 30%, and the penetration rate of the gray scale is correspondingly adjusted to 10/7 of the original image; the first backlight brightness 902 is the original backlight brightness, the second backlight brightness 903 is the backlight brightness obtained by performing content analysis and then is found to be capable of dimming the backlight brightness by 30%, the third image 905 is an image finally displayed on the liquid crystal display screen when the gray-scale transmittance is adjusted to 10/7 in the original manner and the backlight brightness is adjusted to the second backlight brightness 903, and the display effect of the third image 905 is substantially the same as that of the first image 901.

It should be noted that 30% of the reduction of the power consumption by 30% corresponds to 30% of the gray scale increase, the reduction of the power consumption by 30% does not necessarily correspond to 30% of the gray scale increase of the picture, in practical situations, the ratio of the gray scale increase is determined according to the actual content of the picture, similarly, for the LED backlight light source, 30% of the reduction of the power consumption by 30% corresponds to 30% of the dimming of the backlight brightness, and in practical situations, 30% of the reduction of the power consumption does not necessarily correspond to 30% of the dimming of the backlight brightness, and the specific dimming ratio is different according to the difference of the LED backlight light source.

803. The LCD driving IC adjusts at least one of an amplitude or a pulse width of the LED pulse width modulation signal according to the backlight reduction ratio.

After the backlight reduction ratio of the backlight of the content to be displayed is obtained through the CABC technology, at least one of the amplitude or the pulse width of the LED pulse width modulation signal can be adjusted according to the ratio, and the product of the pulse width and the amplitude of the adjusted LED pulse width modulation signal is the backlight reduction ratio of the product of the pulse width and the amplitude of the LED pulse width modulation signal before adjustment. That is, if the backlight reduction ratio is 70%, that is, the backlight is reduced to 70% of the original backlight, in this case, the product of the pulse width and the amplitude of the adjusted LED pulse width modulation signal is 70% of the product of the pulse width and the amplitude of the LED pulse width modulation signal before adjustment. Where the pulse width is actually the duration of the backlight illumination and the amplitude is actually the current value at the time of the backlight illumination, i.e. the product is physically the product of the current and the time.

It should be noted that the minimum duration unit of the CABC adjustment may be duration of one frame, and the LED pwm signal to be transmitted acquired by the liquid crystal display screen is an LED pwm signal including at least one continuous frame. Namely, different frames on one LED pulse width modulation signal can be adjusted by adopting different CABC, so that the function of adjusting the backlight reduction ratio in real time according to the content to be displayed is achieved.

Optionally, a preset pulse width and a preset amplitude corresponding to the backlight reduction ratio are further set in the liquid crystal display screen, and the preset pulse width and the preset amplitude have multiple obtaining manners, for example, the preset pulse width and the preset amplitude are directly stored in the LED driving IC, and of course, may also be stored in a memory where the LED driving IC can read data, and the specific manner is not limited. The preset pulse width is the backlight reduction proportion of the pulse width of the LED pulse width modulation signal corresponding to the content to be displayed; that is, it is equivalent to only adjust the pulse width so that the product of the pulse width and the amplitude reaches the backlight reduction ratio; the preset threshold is a backlight reduction ratio of the preset amplitude value to the amplitude value of the LED pulse width modulation signal corresponding to the content to be displayed, that is, only the amplitude value is adjusted so that the product of the pulse width and the amplitude value reaches the backlight reduction ratio.

On the basis of the preset pulse width and the preset amplitude, the liquid crystal display screen can adjust the amplitude and/or the pulse width of the LED pulse width modulation signal according to the backlight reduction ratio in the following ways, which are described separately below.

In the first category, only the pulse width is adjusted. There are two different types of situations in this approach, the first being shortening the pulse width. The second is to replace the original one pulse by at least two sub-pulses spaced at a higher frequency than the LED pulse width modulated signal. The following is explained:

first, the pulse width is shortened. At this time, step 803 may be changed to shorten the pulse width of the LED pulse width modulation signal to a preset pulse width according to the backlight reduction ratio. That is, it is only necessary to shorten the pulse width to a preset pulse width directly in accordance with the backlight reduction ratio without adjusting the amplitude. Specifically, referring to fig. 10 and 11, fig. 10 is a diagram of an embodiment of a method for controlling backlight power of a liquid crystal display panel according to an embodiment of the present application, and fig. 11 is a diagram of an embodiment of a method for controlling backlight power of a liquid crystal display panel according to an embodiment of the present application, where fig. 10 and 11 both show pulse waveform diagrams of a duration of two frames, and in both the diagrams, a backlight reduction ratio is taken as an example of 70%, an abscissa is time, and an ordinate is current; wherein the solid line represents the adjusted LED pwm signal, and the dotted line represents the LED pwm signal before adjustment; fig. 10 and 11 differ slightly in the actual adjustment manner, in fig. 10, the rising edge of the pulse is fixed, and the falling edge is advanced, so that the product of the pulse width and the amplitude is 70% of the product of the pulse width and the amplitude before adjustment; while in fig. 11 the falling edge is fixed and the rising edge is delayed, it is also possible to achieve a product of the pulse width and the amplitude of 70% of the product of the pulse width and the amplitude before adjustment.

Second, one pulse is replaced by at least two sub-pulses spaced at a higher frequency than the LED pulse width modulated signal. Step 603 may be changed to adjust the pulse width in the LED pwm signal to at least two sub-pulse widths with intervals according to the backlight reduction ratio, and a sum of the pulse widths of the at least two sub-pulse widths is the preset pulse width. The sum of the widths corresponding to the at least two sub-pulses is 70% of the pulse width of the LED pulse width modulation signal before adjustment. Specifically, referring to fig. 12, fig. 12 is a diagram illustrating an embodiment of a backlight power control method for a liquid crystal display panel according to an embodiment of the present application, where fig. 12 is a diagram illustrating a pulse waveform of a duration of two frames, and fig. 12 illustrates a backlight reduction ratio of 70%, an abscissa is time, and an ordinate is current; FIG. 12 is an enlarged schematic diagram of the pulses of the first frame, wherein the solid line represents the adjusted LED PWM signal and the dashed line represents the LED PWM signal before adjustment; it can be seen that, by adjusting a pulse to a plurality of sub-pulses with the same amplitude, the spacing between the sub-pulses is not limited as long as the sum of the pulse widths of the sub-pulses reaches 70% of the pulse width of the LED pwm signal before adjustment, i.e. the product of the pulse widths and the amplitudes of the sub-pulses can be reached and the sum of the product of the pulse widths and the amplitudes of the sub-pulses is 70% of the product of the pulse widths and the amplitudes before adjustment.

In the second category, only amplitude adjustments are made. At this time, step 603 may be changed to reduce the amplitude of the LED pwm signal to a preset amplitude according to the backlight reduction ratio. That is, the amplitude is directly reduced to the preset amplitude according to the backlight reduction ratio without adjusting the pulse width. Referring to fig. 13 in detail, fig. 13 is a diagram illustrating an embodiment of a backlight power control method for a liquid crystal display panel according to an embodiment of the present application, where fig. 13 illustrates a pulse waveform diagram of a duration of two frames, and fig. 13 illustrates a backlight reduction ratio of 70%, an abscissa is time, and an ordinate is current; wherein the solid line represents the adjusted LED pwm signal, and the dotted line represents the LED pwm signal before adjustment; it can be seen that by directly reducing the amplitude to 70%, it is possible to achieve a product of the pulse width and the amplitude of 70% of the product of the pulse width and the amplitude before adjustment.

And the third type is that the pulse width and the amplitude are adjusted simultaneously, and when the two types of pulse width and amplitude are adjusted simultaneously, three different situations exist, wherein the first type is that the adjusted pulse width is larger than the preset pulse width and the adjusted amplitude is larger than the preset amplitude. The second is that the adjusted pulse width is smaller than the preset pulse width and the amplitude after adjustment is increased relative to the amplitude before adjustment. And the third is that the pulse width after adjustment is increased relative to the pulse width before adjustment and the amplitude after adjustment is smaller than the preset amplitude.

It should be noted that, from the first and second classes, the product of the pulse width and the amplitude, both before and after adjustment, actually represents the area of the pulse. The ratio of the areas before and after adjustment corresponds directly to the backlight reduction ratio, for example, 70% backlight reduction ratio, which actually reduces the area of one pulse of the LED pwm signal before adjustment to 70% of the original area. On the basis of this approach, the two dimensions of the area can thus be adjusted, i.e. pulse width and amplitude. Therefore, in three cases in the third category, the first case is to adjust both the pulse width and the amplitude to be small on the original basis, so that the area meets the requirement of 70% before adjustment, and the second case is to shorten the pulse width and increase the amplitude on the original basis, so that the area meets the requirement of 70% before adjustment. The third is to increase the pulse width and decrease the amplitude on the original basis so that the area meets the requirement of 70% before adjustment.

804. The LCD driving IC outputs the adjusted LED pulse width modulation signal to the LED driving IC.

It can be understood that, after the LED driving IC completes the adjustment of the LED pwm signal, the LED driving IC sends the adjusted LED pwm signal to the LED driving IC, so that the LED driving IC drives the LED backlight light source to emit light.

805. And the LED driving IC controls the LED backlight light source to emit light according to the adjusted LED pulse width modulation signal.

It can be understood that, after receiving the adjusted LED pulse width modulation signal, the LED driving IC supplies power to the LED backlight light source according to the adjusted LED pulse width modulation signal, so that the LED backlight light source emits backlight according to the adjusted LED pulse width modulation signal.

806. And the LED backlight light source sends out backlight according to the adjusted LED pulse width modulation signal.

After the adjustment of the LED pwm signal is completed, the LED pwm signal is sent to the LED backlight source, and the LED backlight source sends backlight according to the adjusted LED pwm signal, so that the effect of the content to be displayed on the LCD is substantially the same as the effect of the content to be displayed sent from the backlight according to the LED pwm signal before the adjustment, that is, the loss of the image display quality is within the preset acceptable range.

In addition, it should be noted that the embodiment shown in fig. 8 is an implementation manner of a liquid crystal display panel adopting the backlight power control method of the embodiment of the present application, in the liquid crystal display panel of the embodiment of the present application, except that the liquid crystal display panel architecture shown in fig. 6 or fig. 7 is adopted, the LCD driver IC determines the backlight reduction ratio through the CABC algorithm and adjusts the LED pulse width modulation signal, a separate adjustment IC may be designed, please refer to fig. 10, fig. 10 is an IC connection schematic diagram of the embodiment of the present application, wherein the adjustment IC is located between the LCD driver IC and the LED driver IC, when the liquid crystal display panel works, the LCD driver IC generates the LED pulse width modulation signal first, the adjustment IC determines the backlight reduction ratio through the CABC algorithm while receiving the LED pulse width modulation signal, and then adjusts the pulse width and the amplitude of the LED pulse width modulation signal, and obtaining the adjusted LED pulse width modulation signal, and sending the adjusted LED pulse width modulation signal to the LED driving IC.

It should be noted that the adjusting IC may be a chip specially designed for the CABC algorithm and adjusting the LED pwm signal, or may be another LCD driver IC, and the LCD driver IC can receive the LED pwm signal sent by the previous LCD driver IC.

In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product.

The computer program product includes one or more computer instructions. When loaded and executed on a computer, cause the processes or functions described in accordance with the embodiments of the invention to occur, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, from one website site, computer, server, or data center to another website site, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can store or a data storage device, such as a server, a data center, etc., that is integrated with one or more available media. The usable medium may be a magnetic medium (e.g., floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., Solid State Disk (SSD)), among others.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be substantially implemented or contributed to by the prior art, or all or part of the technical solution may be embodied in a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. A backlight power control method of a liquid crystal display screen is applied to Virtual Reality (VR), and comprises the following steps:

the method comprises the steps that a Liquid Crystal Display (LCD) acquires a Light Emitting Diode (LED) pulse width modulation signal of the LCD, the LCD adopts a backlight black insertion technology, the pulse width of the LED pulse width modulation signal is the backlight starting time in the time of one frame, and the backlight starting time is one tenth of the display time of one frame;

the LCD adopts a content corresponding backlight control CABC algorithm to determine a backlight reduction proportion, wherein the backlight reduction proportion is the backlight reduction proportion of the content to be displayed corresponding to the LED pulse width modulation signal;

the LCD adjusts at least one of the amplitude or the pulse width of the LED pulse width modulation signal according to the backlight reduction ratio, wherein the product of the pulse width and the amplitude of the adjusted LED pulse width modulation signal is the backlight reduction ratio of the product of the pulse width and the amplitude of the LED pulse width modulation signal before adjustment;

and the LED backlight light source in the LCD emits backlight according to the adjusted LED pulse width modulation signal.

2. The method of claim 1, wherein before the LCD adjusts at least one of an amplitude or a pulse width of the LED PWM signal according to the backlight reduction ratio, the method further comprises:

the LCD acquires a preset pulse width and a preset amplitude, and the preset pulse width and the preset amplitude correspond to the backlight reduction ratio; the preset pulse width is the backlight reduction proportion of the pulse width of the LED pulse width modulation signal corresponding to the content to be displayed; the preset amplitude is a backlight reduction ratio of the amplitude of the LED pulse width modulation signal corresponding to the content to be displayed.

3. The method of claim 2, wherein the adjusting the pulse width or amplitude of the LED pwm signal according to the backlight reduction ratio comprises:

shortening the pulse width of the LED pulse width modulation signal to a preset pulse width according to the backlight reduction proportion; or the like, or, alternatively,

and reducing the amplitude of the LED pulse width modulation signal to a preset amplitude according to the backlight reduction proportion.

4. The method of claim 3, wherein the shortening the pulse width of the LED PWM signal to a preset pulse width according to the backlight reduction ratio comprises:

and adjusting the pulse width in the LED pulse width modulation signal into at least two sub-pulse widths with intervals according to the backlight reduction proportion, wherein the sum of the pulse widths of the at least two sub-pulse widths is the preset pulse width.

5. The method of claim 2, wherein the adjusting the pulse width and the amplitude of the LED pwm signal according to the backlight reduction ratio comprises:

and according to the backlight reduction proportion, shortening the pulse width of the LED pulse width modulation signal to be larger than the preset pulse width, and reducing the amplitude of the LED pulse width modulation signal to be larger than the preset amplitude.

6. The method of claim 2, wherein the adjusting the pulse width and the amplitude of the LED pwm signal according to the backlight reduction ratio comprises:

and shortening the pulse width of the LED pulse width modulation signal to be smaller than the preset pulse width according to the backlight reduction proportion, and increasing the amplitude of the LED pulse width modulation signal.

7. The method of claim 2, wherein the adjusting the pulse width and the amplitude of the LED pwm signal according to the backlight reduction ratio comprises:

and according to the backlight reduction proportion, reducing the amplitude value of the LED pulse width modulation signal to be smaller than the preset amplitude value, and increasing the pulse width of the LED pulse width modulation signal.

8. A liquid crystal display screen is applied to VR, comprising a liquid crystal display screen LCD panel, an LCD driving integrated circuit IC electrically connected with the LCD panel and used for driving the LCD panel, a light emitting diode LED backlight source arranged on the back of the LCD panel, an LED driving IC connected with the LED backlight source and used for driving the LED backlight source, and a LED driving IC connected with the LED driving IC,

the LCD driving IC is used for obtaining an LED pulse width modulation signal of the LCD, the LCD adopts a backlight black insertion technology, the pulse width of the LED pulse width modulation signal is the backlight starting time in the time of one frame, and the backlight starting time is one tenth of the display time of one frame;

the LCD drive IC is also used for determining a backlight reduction proportion by adopting a content corresponding backlight control CABC algorithm, wherein the backlight reduction proportion is the backlight reduction proportion of the content to be displayed corresponding to the LED pulse width modulation signal;

the LCD panel is used for displaying contents to be displayed.

9. The LCD display of claim 8, wherein the LCD driver IC is further configured to:

acquiring a preset pulse width and a preset amplitude, wherein the preset pulse width and the preset amplitude correspond to the backlight reduction proportion of the content to be displayed; the preset pulse width is the backlight reduction proportion of the pulse width of the LED pulse width modulation signal corresponding to the content to be displayed; the preset amplitude is a backlight reduction ratio of the amplitude of the LED pulse width modulation signal corresponding to the content to be displayed.

10. The LCD display of claim 9, wherein the LCD driver IC is specifically configured to:

11. The LCD display of claim 10, wherein the LCD driver IC is specifically configured to:

12. The LCD display of claim 9, wherein the LCD driver IC is specifically configured to:

13. The LCD display of claim 9, wherein the LCD driver IC is specifically configured to:

14. The LCD display of claim 9, wherein the LCD driver IC is specifically configured to:

15. A computer-readable storage medium comprising instructions that, when executed on a computer, cause the computer to perform the method of any of claims 1-7.

16. A computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of any one of claims 1 to 7.