CN108780627B - A kind of backlight power control method of liquid crystal display screen and liquid crystal display screen - Google Patents

Abstract

A backlight power control method of a liquid crystal display screen and a liquid crystal display screen. The method includes: the LCD obtains the 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 the amplitude or the pulse width of the LED pulse width modulation signal according to the backlight reduction ratio ; The LED backlight source in the LCD emits backlight according to the adjusted LED pulse width modulation signal. Since 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, the purpose of reducing the power consumption of the backlight under the same display effect is achieved.

Description

A kind of backlight power control method of liquid crystal display screen and liquid crystal display screen

technical field

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

Background technique

Liquid Crystal Display (LCD) is a liquid crystal layer placed in two parallel glass substrates, a thin film transistor (TFT) is arranged on the lower substrate glass, and a color filter is arranged on the upper substrate glass. The rotation direction of the liquid crystal molecules is controlled by the signal and voltage changes on the TFT, so as to control whether the polarized light of each pixel is emitted or not to achieve the purpose of displaying different colors.

Since the LCD itself does not emit light, it is necessary to provide a backlight source on the back of the LCD to allow the user to see the display content on the LCD. There are currently two common LCD backlight sources. One is the use of cold cathode fluorescent tubes (Cold Cathode Fluorescent Lamp, referred to as CCFL) is used as a backlight source. The advantage of CCFL is that it has good color performance, but its disadvantage is high power consumption; the other is to use light-emitting diode (Light Emitting Diode, referred to as LED) as the backlight source. , Low power consumption, so using LED as a backlight source can achieve high brightness while taking into account the lightness and thinness. The main disadvantage is that the color performance is worse than that of CCFL. However, with the development of LED technology, this gap is narrowing, and in view of the high requirements on the battery life of the current mobile terminal devices, most mobile terminal devices use LED light sources.

In addition, for LCD, since the display principle of LCD is to change the transmittance of the liquid crystal layer to achieve different grayscale pixels by changing the driving voltage, that is, it takes a certain amount of time to convert from one grayscale to an adjacent grayscale. , and measuring the grayscale transition time of an LCD is its slowest transition time. The slowest transition response time of a traditional LCD will be as high as 30 to 40 milliseconds, resulting in the effect of displaying fast moving objects. Smear; the slowest conversion response time of fast LCD can be reduced to 5 to 6 milliseconds, and with the backlight plug-in technology to change the always-on display into a pulsed display, the smear can be effectively reduced.

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

SUMMARY OF THE INVENTION

Embodiments of the present application provide a backlight power control method for a liquid crystal display screen and a liquid crystal display screen to solve the problem of high backlight consumption of current fast LCDs.

A first aspect of the embodiments of the present application provides a backlight power control method for a liquid crystal display screen. In the method, the LCD first acquires the LED pulse width modulation signal of the LCD, and then the content to be displayed corresponding to the LED pulse width modulation signal is obtained. Performing Content Adaptive Brightness Control (CABC) processing to obtain the backlight reduction ratio of the backlight of the content to be displayed, and then adjusting at least one of the amplitude or pulse width of the LED pulse width modulation signal according to the backlight reduction ratio. One, so that the product of the pulse width and the amplitude of the adjusted LED PWM signal is the backlight reduction ratio of the product of the pulse width and the amplitude of the LED PWM signal before adjustment; The LED pulse width modulation signal emits a backlight, that is, light is emitted according to the pulse width and amplitude of the LED pulse width modulation signal.

It can be seen that since at least one of the width or amplitude of the LED pulse width modulation signal is adjusted according to the calculated backlight reduction ratio before the LED pulse width modulation signal is sent out, the proportional reduction of the backlight will bring The power consumption is reduced, so that the power consumption of the LED backlight light source when emitting light according to the adjusted LED pulse width modulation signal is lower than that of the LED backlight light source according to the LED pulse width modulation signal before adjustment, so as to achieve the same power consumption. The purpose of reducing the power consumption of the backlight under the display effect.

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

In some embodiments, the way of adjusting one of the pulse width and the amplitude is to adjust the pulse width or the amplitude of the LED pulse width modulation signal according to the backlight reduction ratio. The pulse width adjustment may specifically be to shorten the 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 adjust the LED pulse width according to the backlight reduction ratio. The amplitude of the signal is reduced to a preset amplitude. It can be seen that when one of the pulse width and the amplitude is adjusted individually, it only needs to be directly adjusted to the corresponding preset pulse width or amplitude. Fast adjustment can be achieved, and the realizability of the display backlight power control method can be enhanced.

In some embodiments, there is another way to adjust only the pulse width, that is, according to the backlight reduction ratio, the pulse width in the LED pulse width modulation signal is adjusted to at least two sub-pulse widths with intervals, The sum of the pulse widths of the at least two sub-pulse widths is the preset pulse width. In this method, it is equivalent to replace the original pulse of the LED pulse width modulation signal with a high frequency pulse, so that one pulse of the LED pulse width modulation signal becomes a plurality of sub-pulses, but the sum of the pulse widths of these sub-pulses is the preset pulse. It can also achieve the purpose that 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 the adjustment.

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

In some embodiments, the adjustment of the pulse width and the amplitude at the same time may also be, according to the backlight reduction ratio, shorten the pulse width of the LED pulse width modulation signal to be smaller than the preset pulse width, and increase the pulse width of the LED pulse width modulation signal. The amplitude of the LED PWM signal. In this method, 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 equal to the ratio of the backlight reduction of the product of the pulse width and the amplitude before adjustment, it is necessary to adjust the amplitude. to increase. The realizability of the display backlight power control method can be enhanced.

In some embodiments, the adjustment of the pulse width and the amplitude at the same time can also be: reducing the amplitude value of the LED pulse width modulation signal to be smaller than the preset amplitude value according to the backlight reduction ratio, and increasing the The pulse width of the LED pulse width modulation signal. In this method, 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 equal to the backlight reduction ratio of the product of the pulse width and the amplitude before adjustment, it is necessary to adjust the pulse width. to increase. 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 screen, which includes an LCD panel, an LCD driving integrated circuit (Integrated circuit, IC for short) electrically connected to the LCD panel and used for driving the LCD panel, the The back of the LCD panel is also provided with an LED backlight source, the LED backlight source is further connected with an LED driver IC for driving the LED backlight source, and the LCD driver IC is also connected with the LED driver IC, wherein,

The LCD driver IC is used to obtain the LED pulse width modulation signal of the LCD;

The LCD driver IC is further configured to use the content-corresponding backlight control CABC algorithm to determine the backlight reduction ratio, where the backlight reduction ratio is the backlight reduction ratio of the backlight of the content to be displayed corresponding to the LED pulse width modulation signal;

The LCD driving IC is further configured to adjust 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;

The LED driver IC is used to drive the LED backlight light source to emit backlight according to the adjusted LED pulse width modulation signal;

The LCD panel is used to display the content to be displayed.

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

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

In some embodiments, the LCD driving IC is specifically configured to adjust the pulse width of the LED pulse width modulation signal into at least two sub-pulse widths with intervals according to the backlight reduction ratio, and the at least two sub-pulse widths are The sum of the pulse widths is the preset pulse width.

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

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

In some embodiments, the LCD driving IC is specifically configured to reduce the amplitude value of the LED pulse width modulation signal to be smaller than the preset amplitude value according to the backlight reduction ratio, and increase the amplitude value of the LED pulse width modulation signal. Pulse Width.

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

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

Description of drawings

Fig. 1 is the schematic diagram of VR display system;

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

Figure 3 shows a schematic diagram of a fast-response LCD that uses black insertion technology for traditional LCD and VR to display high-speed moving pictures;

Fig. 4 is the schematic diagram of fast response LCD using black insertion technology;

Fig. 5a is the schematic diagram of no-insertion black always-on display;

Fig. 5b is a schematic diagram of a black-inserted pulse display;

6 is a schematic structural diagram of a liquid crystal display screen according to an embodiment of the present application;

7 is a schematic structural diagram of a liquid crystal display screen according to an embodiment of the present application;

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

Fig. 9 is the schematic diagram that adopts CABC dynamic backlight to adjust display content;

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

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

12 is a diagram of an embodiment of a backlight power control method for a liquid crystal display screen 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 ways

Embodiments of the present application provide a backlight power control method for a liquid crystal display screen and a liquid crystal display screen to solve the problem of high backlight consumption of current fast LCDs.

In order to make those skilled in the art better understand the solutions of the present application, the embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It is to be understood that data so used may be interchanged under appropriate circumstances so that the embodiments described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" or "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those expressly listed steps or units, but may include other steps or units not expressly listed or inherent to these processes, methods, products or devices.

In the field of Virtual Reality (VR), the head-mounted display is mainly used at present, that is, two different images are displayed to the two eyes by setting one or two display screens in one head-mounted display. Both are driven by the display chip of the display screen. There are subtle differences between the two images. The difference is similar to the human binocular parallax. A lens is used between the human eye and the display screen to generate an enlarged virtual image to simulate, thereby generating a real-world image. For the sense of immersion, please refer to Fig. 1 for details. Fig. 1 is a schematic diagram of a VR display system. The distance of the surface 104 is L3, that is, the picture generated at the distance L3 in front of the human eye 101 perceived by people, wherein the eyepiece 102 can be a Fresnel lens, also known as a threaded lens, which is mostly made of polyolefin material by injection molding The thin sheet is also made of glass. One side of the lens surface is smooth, and the other side is engraved with concentric circles from small to large. Its texture is designed according to the requirements of light interference, interference, relative sensitivity and receiving angle, which can solve the problem. The phenomenon of darkening and blurring of the corners of ordinary convex lenses.

When the head of the human body wearing the VR headset moves in different directions, the changing image during the movement will be displayed on the display screen. Animation simulates the visual changes that the human eye would see in the real world. However, because it is a moving or even high-speed moving picture, when such content is displayed on a traditional LCD, there will be serious smearing on the picture, which will cause dizziness and nausea to users using VR. Therefore, VR headsets are generally used. It is said that the adoption is a fast-response liquid crystal display with backlight insertion black technology, and its slowest-order conversion response event is 5-6 milliseconds. As shown in Figure 2, Figure 2 is a schematic diagram of the grayscale conversion in the liquid crystal display, in which the abscissa in the figure is the time, and the ordinate is the grayscale percentage, that is, if the grayscale has 256 steps from black to white, black is the 0% position , white is the 100% position. The curve in the figure represents the process of the liquid crystal converting from grayscale N to grayscale M, and then from grayscale M to grayscale N. Grayscale N is represented by Gray(N) in Figure 2, and grayscale M is represented by Gray in Figure 2. (M) represents, where N is less than M, both N and M are the first order in the 256-level grayscale, Tr is the response time from grayscale N to grayscale M, and Tf is the response time from grayscale M to grayscale N.

As shown in Figure 3, it is a schematic diagram of the fast-response LCD with black insertion technology used for traditional LCD and VR to display high-speed moving pictures. It can be seen that the smear of the traditional LCD is more serious, while the smear of the fast-response LCD using the black insertion technology is more serious. There is almost no shadow. Among them, the use of the backlight black insertion technology can achieve a pulse type, so that the smear is greatly reduced compared to the always-on display. For details, please refer to Figure 4, Figure 5a and Figure 5b. Figure 4 is a schematic diagram of the fast response LCD using the black insertion technology. , Figure 5a is a schematic diagram of a black always-on display without plugging; Figure 5b is a schematic diagram of a black pulse display; in Figure 4, the P1 stage represents the backlight off stage, the P2 stage represents the backlight on stage, and the S1 stage in the P1 stage is the data In the scanning stage, the voltage of the gray scale that each pixel needs to be displayed will be determined in this stage; the S2 stage in the P1 stage is the liquid crystal response operation part after the data scanning is completed; Each pixel needs to display the gray-scale voltage to rotate the liquid crystal to the corresponding angle. After completing these two operations, you can perform the P2 stage to turn on the backlight for display; the P1 stage plus the P2 stage means the duration of one frame. It can be seen that each frame includes the backlight off section and the backlight on section. Vsync means The synchronization of each frame, for example, the length of the backlight-on segment is one tenth of the display time of a frame.

It can be seen that, in fact, the data scanning stage and the liquid crystal response stage are the parts that do not need to be seen by the user, that is, this part can be carried out without turning on the backlight, and the black insertion technology is carried out using this feature.

In Figures 5a and 5b, each small square represents a pixel. Figure 5a shows the display mode without black insertion, and Figure 5b shows the display mode with 50% black insertion. Comparing Figures 5a and 5b, it can be seen that in the same In the case of the frame, the smear length of the always-on display without black insertion is 4 pixels, and the smear length of the pulse display method with 50% black insertion is only 2 pixels.

In addition, for the traditional LCD, there are two ways to reduce the backlight power consumption of the LCD. There are two methods: Light Adaptive Brightness Control (LABC) and CABC. In the case of VR system, it is basically not used. CABC technology recognizes the content and controls the backlight according to the content.

Among them, the CABC dynamic backlight adjustment is to adjust the backlight according to the specific displayed content. By analyzing the content to be displayed, the brightness of the backlight is reduced. At the same time, in order to ensure that the displayed content is basically the same as before the CABC adjustment is performed, it is necessary to adjust the transmittance of the grayscale in the content to perform brightness compensation. For the liquid crystal display, the display brightness of the liquid crystal display perceived by the human eye is obtained by multiplying the luminous brightness of the LED backlight light source by the transmittance of the gray scale. The penetration rate of a certain grayscale is the voltage corresponding to the grayscale.

For example, if the brightness of the LED backlight source is 1000 units, the transmittance of the X-level gray scale is 60%, and the value of X is between 0 and 255, the final display brightness of the LCD screen is 600 units. If it is found through CABC calculation that the backlight can be reduced to 80%, that is, the backlight becomes 800 units, and in order to make the final display brightness still 600 units, it is necessary to adjust the transmittance of the X-level grayscale, such as the transmittance adjustment. If it is 75% (actually it is the adjustment of the voltage), the final display brightness of the LCD screen is 800 units multiplied by 75%, which is still 600 units. Thereby, the luminous brightness of the LED backlight light source can be reduced without losing the display brightness.

When using CABC, it is necessary to add the content analysis function to the LCD driver IC. The addition of this function can be realized by software or by adding a specific content analysis circuit in the LCD driver IC to realize the content analysis function. The specific working process of CABC is as follows:

First, the application processor sends the content to be displayed (such as picture data) to the LCD driver IC, and the content analysis function analyzes the picture data, and determines the proportion of backlight reduction according to certain rules. For example, in analyzing the image data, if the proportion of dark or black parts exceeds a certain proportion, the backlight reduction ratio is set to a fixed value; of course, the rule can be preset when designing the content analysis function or circuit. In addition, In the LCD driver IC, the corresponding relationship between the backlight reduction ratio and the adjustment of the transmittance of the gray scale is also stored. Next, after the backlight reduction ratio is determined, the grayscale transmittance adjustment is performed according to the corresponding relationship between the backlight reduction ratio and the grayscale transmittance adjustment. Finally, the LCD driver IC drives the LCD panel to use the adjusted grayscale. The transmittance shows the content to be displayed, and the LCD driver IC drives the backlight source of the LCD to reduce the backlight brightness according to the backlight reduction ratio, so that the effect of the final displayed picture is basically the same as that of the picture before CABC. Since the brightness of the backlight light source is reduced, power consumption can be reduced. Therefore, this CABC technology is suitable for use in mobile devices that use batteries as power sources.

Due to the characteristics of the fast response liquid crystal display screen, its backlight power consumption is relatively high. In order to solve this problem, the embodiment of the present application provides a backlight power control method for a fast response liquid crystal display screen, that is, a liquid crystal display screen to solve the problem of backlight power consumption. higher problem. First, the structure of the liquid crystal display screen of the present application will be described. Please refer to FIG. 6 . FIG. 6 is a schematic view of the structure of the liquid crystal display screen of the embodiment of the present application. The liquid crystal display screen includes an LCD panel and an LED backlight source disposed on the back of the LCD panel, wherein the LCD panel is connected with an LCD driver IC, the LED backlight source is connected with an LED driver IC that drives the LED backlight source, and the LCD driver IC is also connected to to the LED driver IC. The specific working process of the liquid crystal display can be as follows: the LCD driver IC receives the content to be displayed, the LCD driver IC generates a PWM signal, and then sends the PWM signal to the LED driver IC, and the LED driver IC drives the LED to emit light according to the PWM signal.

It should be noted that the LED driver IC and the LCD driver IC can be set on different functional modules. For details, please refer to FIG. 7 . FIG. 7 is a schematic diagram of the structure of the liquid crystal display screen according to the embodiment of the present application. The part is provided with MPU or CPU, and LED driver IC. The LED driver IC can be WLED (white LED) driver IC, while the LCD module is provided with LCD panel, LCD driver IC, and a plurality of LED driver ICs arranged on the back of the LCD panel. LEDs, of course, these LEDs can also be WLEDs. The specific working process can be that the MPU or CPU sends the content to be displayed to the LCD driver IC, and then the LCD driver IC generates a PWM signal and sends it to the LED driver IC, and on the other hand, the LCD driver IC also outputs the content to the LCD panel according to the content to be displayed. , and then, after receiving the PWM signal, the LED driver IC will adjust the current input to the LED at the same time, so that the LED emits light.

The following describes the backlight power control method of the liquid crystal display screen of the embodiment of the present application. The backlight power control method of the liquid crystal display screen of the embodiment of the present application can be used in the structure of the liquid crystal display screen shown in FIG. 6 or FIG. 7 . The following describes the backlight power control method of the liquid crystal display screen according to the embodiment of the present application by taking the structure shown in FIG. 6 as an example. Please refer to FIG. 8. FIG. 8 is a diagram of an embodiment of a method for controlling the backlight power of a liquid crystal display screen according to an embodiment of the present application. The method may include:

801. The LCD driver IC acquires the LED pulse width modulation signal of the LCD.

Among them, the liquid crystal display adopts the black insertion technology, so the LED signal output to the LED backlight light source is an LED pulse width modulation signal, and the pulse width of the pulse width modulation signal is the length of time during which the backlight is turned on in one frame.

Among them, PWM is to control the on-off of the switching device of the inverter circuit, so that the output terminal can obtain a series of pulse control methods with equal amplitude. If the amplitude is not changed, the width of each pulse of the PWM signal is modulated according to certain rules, that is, the output voltage of the inverter circuit can be changed by adjusting the duty cycle of the pulse. Of course, the adjustment of the pulse width can also change the PWM The output frequency of the signal.

The way to use PWM technology for LED dimming is to change the on-time of the forward current by periodically turning on and off the LED to control the light and dark time of the LED; since the brightness perceived by the human eye is a cumulative process, that is, in a cycle The larger the proportion of the time the LED is bright in the entire cycle, the brighter the human eye will feel. If the frequency of LED brightness exceeds 100Hz, then the human eye sees the average brightness, not the LED flickering. At this time, when the amplitude remains unchanged, when the pulse width is adjusted, increasing the pulse width will make people The eye perceives an increase in brightness, and vice versa, it perceives a decrease in brightness. The operating frequency of the LED backlight light source of the LCD screen with PWM dimming is generally around 200Hz-1000Hz. Since the essence of PWM lighting is the process of "on-off-on-off", it is equivalent to the visible light in a certain frequency to the human eye. When the PWM frequency is higher, that is, the higher the frequency of flickering, the weaker the perception of the impact to the human eye; at the same time, the higher the brightness, the perception of this flickering impact can also be reduced.

It can be seen that the PWM dimming method is different from the linear dimming method that changes the LED brightness by changing the current size of the LED. PWM dimming only makes the LED work discontinuously, so that the LED brightness can be changed without changing the current size.

It should be noted that, for LCD, due to different refresh rates, the duration of one frame is also different. For example, if the refresh rate of LCD is set to 60hz, it means that the image displayed on the LCD is redrawn 60 times per second. The duration of one frame is 1/60 of a second. Similarly, if the refresh rate of the LCD is 90hz, it means that the image displayed on the LCD is redrawn 90 times in one second, and the duration of one frame becomes 1/90. second. Of course, for the VR field, the higher the refresh rate, the better. In the case of a low refresh rate, for example, the picture seen at 60hz will have obvious flickering and unstable situation, and this situation will appear when the scene moves with the viewing angle. Eye discomfort, dizziness and other symptoms. For the LCD in the embodiment of the present application, the refresh rate may be an LCD with a refresh rate exceeding 90 Hz, which can effectively reduce the above symptoms.

802. The LCD driver IC uses the CABC algorithm to determine the proportion of backlight reduction.

Wherein, the backlight reduction ratio is the backlight reduction ratio of the backlight of the content to be displayed corresponding to the LED pulse width modulation signal. The CABC technology can adjust the backlight reduction ratio in real time according to the content to be displayed. The following describes an example, please refer to FIG. 9 , FIG. 9 is a schematic diagram of using CABC dynamic backlight to adjust the display content. Among them, the first image 901 is the original image, the second image 903 is the content analysis and it is found that the backlight brightness can be reduced by 30%, and the transmittance of the gray scale is adjusted accordingly to the original 10/7; the first backlight brightness 902 is The original backlight brightness, the second backlight brightness 903 is the backlight brightness after content analysis, and it is found that the backlight brightness can be dimmed by 30%. The third image 905 is adjusted to the original 10/7 combined with the grayscale transmittance. And the image finally displayed on the LCD screen when the backlight brightness is adjusted to the second backlight brightness 903 , the display effect of the third image 905 is basically the same as the display effect of the first image 901 .

It should be noted that a 30% reduction in power consumption corresponds to a 30% increase in grayscale is indicative, and a 30% reduction in power consumption does not necessarily correspond to a 30% increase in the grayscale of the image. In the same way, for the LED backlight light source, it is also indicative that the power consumption is reduced by 30% and the backlight brightness is dimmed by 30%, but the actual power consumption reduction of 30% does not necessarily correspond to When the backlight brightness is dimmed by 30%, the specific dimming ratio varies depending on the LED backlight source.

803. The LCD driving IC 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, 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 adjusted LED pulse The product of the pulse width and the amplitude of the 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 reduction is 70% of the original backlight. At this time, the product of the pulse width and the amplitude of the adjusted LED PWM signal is the pulse width of the unadjusted LED PWM signal. 70% of the product of the magnitude. Among them, the pulse width is actually the duration of the backlight lighting, and the amplitude is actually the current value when the backlight is lighting, that is, the product is physically the product of current and time.

It should be noted that the minimum duration unit of the CABC adjustment may be the duration of one frame, and the LED pulse width modulation signal to be sent obtained by the liquid crystal display is an LED pulse width modulation signal including at least one continuous frame. That is to say, different frames on an LED pulse width modulation signal can be adjusted by different CABC, so as to achieve the effect of adjusting the backlight reduction ratio in real time according to the content to be displayed.

Optionally, a preset pulse width and preset amplitude corresponding to the backlight reduction ratio are also set in the liquid crystal display screen. The preset pulse width and preset amplitude can be obtained in multiple ways, such as the preset pulse width and preset amplitude. The pulse width and preset amplitude are directly stored on the LED driver IC, of course, they can also be stored in the memory where the LED driver IC can read data, and the specific method is not limited. The preset pulse width is the backlight reduction ratio 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 adjusting the pulse width so that the product of the pulse width and the amplitude reaches the backlight reduction ratio; The set threshold value is the preset amplitude value of the backlight reduction ratio of the amplitude of the LED pulse width modulation signal corresponding to the content to be displayed, that is, it is equivalent to only adjusting the amplitude value so that the product of the pulse width and the amplitude value reaches the backlight value. Decrease the ratio.

On the basis of having a preset pulse width and a preset amplitude, the liquid crystal display screen can adjust the amplitude and/or pulse width of the LED pulse width modulation signal according to the backlight reduction ratio. Be explained.

In the first category, only the pulse width is adjusted. There are two different situations in this way. The first situation is to shorten the pulse width. The second is to replace the original one pulse by at least two sub-pulses with a higher frequency and spacing than the LED pulse width modulation signal. It is explained below:

The first is to shorten the pulse width. At this time, step 803 can 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 the preset pulse width directly according to the backlight reduction ratio without adjusting the amplitude. 10 and FIG. 11 , FIG. 10 is a diagram of an embodiment of the backlight power control method of the liquid crystal display screen according to the embodiment of the present application, and FIG. 11 is an implementation of the backlight power control method of the liquid crystal display screen according to the embodiment of the present application. For example, Figure 10 and Figure 11 both represent the pulse waveforms of the duration of two frames. In both figures, the backlight reduction ratio is 70% as an example, the abscissa is the time, and the ordinate is the current; the solid line represents the adjustment After the LED pulse width modulation signal, the dotted line represents the LED pulse width modulation signal before adjustment; the difference between Figure 10 and Figure 11 is that the actual adjustment method is slightly different. In Figure 10, the rising edge of the pulse is fixed, and the falling edge is fixed. advance, so that the product of pulse width and amplitude is 70% of the product of pulse width and amplitude before adjustment; while in Figure 11, the falling edge is fixed and the rising edge is delayed, which can also achieve pulse width and amplitude. The product of is 70% of the product of the pulse width and amplitude before adjustment.

Second, the original one pulse is replaced by at least two sub-pulses with higher frequency and spacing than the LED pulse width modulation signal. Step 603 can be changed to adjust the pulse width of the LED pulse width modulation signal into 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. The sum of the widths corresponding to the widths of at least two sub-pulses is 70% of the pulse width of the LED pulse width modulation signal before adjustment. For details, please refer to FIG. 12. FIG. 12 is a diagram of an embodiment of a backlight power control method for a liquid crystal display screen according to an embodiment of the present application, wherein FIG. 12 shows a pulse waveform diagram of the duration of two frames. In FIG. 12, the backlight reduction ratio is used Taking 70% as an example, the abscissa is time, and the ordinate is current; the bottom of Figure 12 is an enlarged schematic diagram of the pulse of the first frame, in which the solid line represents the adjusted LED pulse width modulation signal, and the dotted line represents the LED pulse before adjustment. Width modulation signal; it can be seen that by adjusting a pulse into multiple sub-pulses with the same amplitude, the spacing of these sub-pulses is not limited, as long as the sum of the pulse widths of these sub-pulses reaches the LED pulse width modulation signal before adjustment The product of the pulse width and the amplitude of these sub-pulses can be reached, and the accumulated result is 70% of the product of the pulse width and the amplitude before adjustment.

In the second category, only the amplitude is adjusted. At this time, step 603 can be changed to reduce the amplitude of the LED pulse width modulation signal to a preset amplitude according to the backlight reduction ratio. That is, the amplitude can be directly reduced to a preset amplitude according to the backlight reduction ratio without adjusting the pulse width. For details, please refer to FIG. 13 . FIG. 13 is a diagram of an embodiment of the backlight power control method of the liquid crystal display screen according to the embodiment of the present application, wherein the FIG. 13 shows the pulse waveform diagram of the duration of two frames. In FIG. 13 , the backlight reduction ratio is used. Take 70% as an example, the abscissa is the time, and the ordinate is the current; 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 directly subtract the amplitude If it is as small as 70%, the product of the pulse width and the amplitude can be reached to be 70% of the product of the pulse width and the amplitude before adjustment.

The third type is to adjust the pulse width and amplitude at the same time. When the two are adjusted at the same time, there will be three different situations. The first is that the adjusted pulse width is greater than the preset pulse width and the adjusted amplitude is greater than preset amplitude. The second is that the adjusted pulse width is smaller than the preset pulse width and the adjusted amplitude is increased relative to the pre-adjusted amplitude. The third is that the adjusted pulse width is increased relative to the pre-adjusted pulse width and the adjusted amplitude is smaller than the preset amplitude.

It should be noted that, from various situations in the first and second categories, it can be found that the product of the pulse width and the amplitude, whether before or after adjustment, actually represents the area of the pulse. The ratio of the area before adjustment and after adjustment directly corresponds to the ratio of backlight reduction. For example, the backlight reduction ratio is 70%, which actually reduces the area of one pulse of the LED PWM signal before adjustment to the original 70%. %. On the basis of this approach, two dimensions of the area can be adjusted, namely pulse width and amplitude. Therefore, among the three cases in the third category, the first is to reduce the pulse width and amplitude on the basis of the original, so that the area meets the requirement of 70% before adjustment, and the second It is to shorten the pulse width and increase the amplitude on the original basis to make the area meet the requirement of 70% before adjustment. The third is to increase the pulse width and reduce 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 driver IC completes the adjustment of the LED pulse width modulation signal, it will send the adjusted LED pulse width modulation signal to the LED driver IC, so that the LED driver IC drives the LED backlight light source to emit light.

805. The LED driver 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 driver IC will supply power to the LED backlight according to the adjusted LED pulse width modulation signal according to the pulse of the adjusted LED pulse width modulation signal. The LED backlight light source emits a backlight according to the adjusted LED pulse width modulation signal.

806. The LED backlight light source emits a backlight according to the adjusted LED pulse width modulation signal.

Wherein, after the adjustment of the LED pulse width modulation signal is completed, the LED pulse width modulation signal can be sent to the LED backlight light source, and the LED backlight light source sends out the backlight according to the adjusted LED pulse width modulation signal, so as to make the LCD display The effect of the content to be displayed is basically the same as the effect of the content to be displayed displayed by the backlight according to the LED pulse width modulation signal before adjustment, that is, the loss of image display quality is within a preset acceptable range.

In addition, it should be noted that the embodiment shown in FIG. 8 is an implementation of the liquid crystal display screen using the backlight power control method of the embodiment of the present application. In the LCD structure shown in 7, 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 can also be designed, please refer to Figure 10. Figure 10 shows the The schematic diagram of the IC connection in 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 screen is working, the LCD driver IC first generates an LED pulse width modulation signal, and the adjustment IC receives the LED pulse width modulation signal. At the same time as the pulse width modulation signal, the backlight reduction ratio will be determined by the CABC algorithm, and then the pulse width and amplitude of the LED pulse width modulation signal will be adjusted to obtain the adjusted LED pulse width modulation signal, and then sent to the LED driver. IC.

It should be noted that the adjustment IC can be a chip specially designed for the CABC algorithm and adjusting the LED pulse width modulation signal, or it can be another LCD driver IC, which can receive the LED pulse width sent by the previous LCD driver IC. Modulated signal.

In the above-mentioned embodiments, it may be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented in software, it can 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 the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer may be a general purpose computer, special purpose computer, computer network, or other programmable device. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server, or data center Transmission to another website site, computer, server, or data center is by wire (eg, coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (eg, infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be stored by a computer, or a data storage device such as a server, data center, etc., which includes one or more available media integrated. The usable media may be magnetic media (eg, floppy disks, hard disks, magnetic tapes), optical media (eg, DVDs), or semiconductor media (eg, Solid State Disk (SSD)), among others.

Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, device and unit described above may refer to the corresponding process in the foregoing method embodiments, which will not be repeated here.

In the several embodiments provided in this application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the apparatus embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored, or not implemented. On the other hand, the shown or discussed mutual coupling or direct coupling or communication connection may be through some interfaces, indirect coupling or communication connection of devices or units, and may be in electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution in this embodiment.

In addition, each functional unit in the embodiments of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above-mentioned integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.

The integrated unit, if implemented in the form of a software functional unit and sold or used as an independent product, may be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the present application can be embodied in the form of software products in essence, or the parts that contribute to the prior art, or all or part of the technical solutions, and the computer software products are stored in a storage medium , including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk and other media that can store program codes .

As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: The technical solutions described in the embodiments are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions and scope of the embodiments of the present application.

Claims (16)

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 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 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:

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.

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

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.

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

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.

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

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.

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

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.

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.

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