CN113129845B - Backlight driving method and display panel - Google Patents
Backlight driving method and display panel Download PDFInfo
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- CN113129845B CN113129845B CN202110389512.1A CN202110389512A CN113129845B CN 113129845 B CN113129845 B CN 113129845B CN 202110389512 A CN202110389512 A CN 202110389512A CN 113129845 B CN113129845 B CN 113129845B
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
- G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2300/00—Aspects of the constitution of display devices
- G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
- G09G2300/0809—Several active elements per pixel in active matrix panels
- G09G2300/0842—Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/08—Details of timing specific for flat panels, other than clock recovery
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/06—Adjustment of display parameters
- G09G2320/0626—Adjustment of display parameters for control of overall brightness
- G09G2320/064—Adjustment of display parameters for control of overall brightness by time modulation of the brightness of the illumination source
Abstract
The application discloses a backlight driving method and a display panel. The backlight driving method provided by the application modulates the low-level pulse width of the scanning signal by adopting a pulse width modulation technology. The number of high level pulses is reduced by increasing the low level pulse width to increase the pulse period, thereby reducing the high level pulse time. The time that the TFT is subjected to the high level voltage is also reduced, thereby improving the stability of the TFT and also improving the problem of threshold voltage shift of the TFT.
Description
Technical Field
The application relates to the technical field of display, in particular to a backlight driving method and a display panel.
Background
The Mini-LED (Mini LED) backplane drive currently includes Active Matrix (AM) drive and Passive Matrix (PM) drive. Since a Thin Film Transistor (TFT) in the Mini-LED AM driver can perform a switching function, many Integrated Circuits (ICs) can be omitted compared to the PM, and thus, the AM driver has a lower cost than the PM driver. The AM-driven backplane technology currently uses amorphous silicon (α -Si), Indium Gallium Zinc Oxide (IGZO) and Low Temperature Polysilicon (LTPS), and the stability of the TFT greatly affects the brightness and taste of the MiniLED. In the course of research and practice on the prior art, the inventors of the present application found that the stability of the TFT is strongly correlated with the time of scanning a high level (Scan high) of a signal, and that an excessively long high level time aggravates the threshold voltage shift (Vth shift) of the TFT, resulting in a decrease in stability.
Disclosure of Invention
The application provides a backlight driving method and a display panel, which can enhance the stability of a thin film transistor.
The application provides a backlight driving method, comprising the following steps:
providing a pulse width modulation signal;
modulating the low-level pulse width of a scanning signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scanning signal to be modulated, so that the number of high-level pulses of the scanning signal after modulation is less than that of the scanning signal to be modulated;
and outputting the modulated scanning signal to a backlight driving circuit.
Optionally, in some embodiments of the present application, in a frame, the scan signal to be modulated includes a plurality of initial pulse periods, and the modulating a low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase a pulse period of the scan signal to be modulated, so that a number of times of high-level pulses of the modulated scan signal is less than a number of times of high-level pulses of the scan signal to be modulated, including:
and increasing the pulse width of a low level, and modulating at least one initial pulse period into a first pulse period, wherein the time of the first pulse period is the time of at least two initial pulse periods, so that the modulated scanning signal comprises a plurality of first pulse periods.
Optionally, in some embodiments of the present application, the scanning signal to be modulated in one frame includes 127 initial pulse periods, and the modulating the low-level pulse width of the scanning signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scanning signal to be modulated, so that the number of high-level pulses of the modulated scanning signal is less than the number of high-level pulses of the scanning signal to be modulated, including:
modulating the scanning signal to be modulated in one frame to comprise one initial pulse period and p first pulse periods, wherein the time of the first pulse period is the time of two initial pulse periods; wherein p has a value of 63.
Optionally, in some embodiments of the present application, in a frame, the scan signal to be modulated includes a plurality of initial pulse periods, and the modulating a low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase a pulse period of the scan signal to be modulated, so that a number of times of high-level pulses of the modulated scan signal is less than a number of times of high-level pulses of the scan signal to be modulated, including:
increasing the low-level pulse width, modulating at least one initial pulse period into a first pulse period, and modulating at least one initial pulse period into a second pulse period, so that the modulated scanning signal comprises a plurality of first pulse periods and a plurality of second pulse periods, wherein the time of the initial pulse period is less than that of the first pulse period, and the time of the first pulse period is less than that of the second pulse period.
Optionally, in some embodiments of the present application, the time of the first pulse period is the time of two initial pulse periods, and the time of the second pulse period is the time of four initial pulse periods.
Optionally, in some embodiments of the present application, in a frame, the scan signal to be modulated includes a plurality of initial pulse periods, and the modulating a low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase a pulse period of the scan signal to be modulated, so that a number of times of high-level pulses of the modulated scan signal is less than a number of times of high-level pulses of the scan signal to be modulated, including:
increasing the pulse width of a low level, and modulating a plurality of initial pulse periods in one frame into n first pulse periods and m second pulse periods, so that the modulated scanning signal in one frame comprises one initial pulse period, n first pulse periods and m second pulse periods, the time of the first pulse period is the time of two initial pulse periods, and the time of the second pulse period is the time of four initial pulse periods; wherein the sum of n and m is 32, and m and n are positive integers more than 1.
Optionally, in some embodiments of the present application, in a frame, the scan signal to be modulated includes 127 initial pulse periods, and the modulating a low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase a pulse period of the scan signal to be modulated, so that a number of times of high-level pulses of the modulated scan signal is less than a number of times of high-level pulses of the scan signal to be modulated, including:
and modulating the scanning signal to be modulated in one frame to comprise one initial pulse period, one first pulse period and 31 second pulse periods.
Optionally, in some embodiments of the present application, the modulated scanning signal includes one of the initial pulse periods, one of the first pulse periods, and 31 of the second pulse periods, which are sequentially arranged.
Optionally, in some embodiments of the present application, the backlight driving method is applied to a backlight driving circuit, where the backlight driving circuit includes a first transistor, a second transistor, a storage capacitor, and a light emitting device;
the source electrode of the first transistor is connected to the cathode of the light-emitting device, the drain electrode of the first transistor is grounded, and the grid electrode of the first transistor is electrically connected with a first node;
A source electrode of the second transistor is connected with a data signal, a drain electrode of the second transistor is electrically connected with a first node, and a grid electrode of the second transistor is connected with a modulated scanning signal;
the first end of the storage capacitor is electrically connected with the first node, and the second end of the storage capacitor is grounded;
and the anode of the light-emitting device is connected with a power supply signal.
Optionally, in some embodiments of the present application, when the modulated scanning signal is at a high level, the data signal is at a high level, and a high-level pulse width of the data signal is greater than a high-level pulse width corresponding to the modulated scanning signal.
Correspondingly, the application provides a display panel, the display panel includes a backlight module, a backlight driving circuit is arranged on the backlight module, and the backlight driving circuit is driven by the backlight driving method.
The application discloses a backlight driving method and a display panel. The backlight driving method provided by the application modulates the low-level pulse width of the scanning signal by adopting a pulse width modulation technology. The number of high level pulses is reduced by increasing the low level pulse width to increase the pulse period, thereby reducing the high level pulse time. The time that the TFT is subjected to the high level voltage is also reduced, thereby improving the stability of the TFT and also improving the problem of threshold voltage shift of the TFT.
Drawings
In order to more clearly illustrate the technical solutions in the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic flow chart of a backlight driving method provided in the present application;
FIG. 2 is a schematic diagram of a scanning signal provided herein;
FIG. 3 is a first schematic diagram of a scanning signal before and after modulation provided by the present application;
FIG. 4 is a second schematic diagram of the scanning signal provided by the present application before and after modulation;
FIG. 5 is a circuit diagram of a backlight driving circuit in the backlight driving method provided in the present application;
FIG. 6 is a timing diagram of a backlight driving circuit in the backlight driving method provided in the present application;
fig. 7 is a schematic structural diagram of a display panel provided in the present application.
Detailed Description
The technical solutions in the present application will be clearly and completely described below with reference to the accompanying drawings in the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In the present application, it is to be understood that terms such as "including" or "having," etc., are intended to indicate the presence of the disclosed features, numbers, steps, actions, components, parts, or combinations thereof, and are not intended to preclude the possibility that one or more other features, numbers, steps, actions, components, parts, or combinations thereof may be present or added.
The application provides a backlight driving method and a display panel. The following are detailed descriptions. It should be noted that the following description of the embodiments is not intended to limit the preferred order of the embodiments.
Referring to fig. 1, fig. 1 is a schematic flow chart of a backlight driving method provided in the present application. The backlight driving method provided by the application specifically comprises the following steps:
11. a pulse width modulation signal is provided.
The Pulse Width Modulation (PWM) technique is to equivalently obtain a desired waveform by modulating the width of a series of pulses. The PWM technique is a very effective technique for controlling an analog circuit using a digital signal of a microprocessor. The pulse width modulation control technology has the advantages of simple structure, easy realization and mature technology, and is widely applied. The PWM signal of the present application is obtained by PWM technology, and will not be described herein.
12. And modulating the low-level pulse width of the scanning signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scanning signal to be modulated, so that the number of high-level pulses of the scanning signal after modulation is less than that of the scanning signal to be modulated.
Referring to fig. 2, fig. 2 is a schematic diagram of a scan signal provided in the present application. Generally, in a display panel, a plurality of rows of backlight driving units are provided, and each row of backlight driving units corresponds to one row of backlight driving circuit. The backlight driving circuits of each row are respectively controlled by scanning signals so as to scan the backlight driving circuits row by row. As shown in fig. 2, for example, the display panel has n rows of backlight driving circuits, and n rows of scanning signals are respectively corresponding to the n rows of scanning signals, which are respectively indicated as Scan1, Scan2, … … Scan (n-1) and Scan (n). Wherein, a high level pulse width plus an adjacent low level pulse width is a pulse period T. That is, the pulse period T indicates the time from the high-level pulse to the next high-level pulse. Here, the low-level pulse width D may also be referred to as a pulse interval.
In the scanning signal of the backlight driving circuit shown in fig. 2, the time from the first line scanning signal Scan1 to the nth line scanning signal Scan (n) is turned on line by line, and the vertical blanking interval (vertical blanking interval) from the next scanning after scanning n lines is added is referred to as a minimum subfield time t. Wherein, the minimum subfield time t is determined according to the gray scale and the resolution of the display panel. For example, for a display panel with 128 gray levels and a resolution of 240Hz, a frame time is 4.17 milliseconds (ms), and 128 gray levels are displayed in a frame, the minimum subfield time t is 32.6 microseconds (μ s). The above is merely an example, and is for better explaining the concept of the minimum subfield time t, and not as a limitation to the present application.
Referring to fig. 3, fig. 3 is a first schematic diagram before and after modulation of a scanning signal provided by the present application. Fig. 3 is a schematic diagram illustrating a pulse period compression of a scan signal in one frame, taking a scan signal of a certain row in fig. 2 as an example.
In some embodiments, the method modulates the low-level pulse width of the scan signal ScanO to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal ScanO to be modulated, so as to reduce the number of high-level pulses of the scan signal ScanO to be modulated, specifically including the following steps:
the low level pulse width is increased to modulate at least one initial pulse period P0 to a first pulse period P1. The first pulse period P1 is at least two initial pulse periods P0, so that the number of high level pulses of the modulated scanning signal is less than that of the scanning signal to be modulated. The scan signal to be modulated ScanO includes a plurality of initial pulse periods P0, and the scan signal to be modulated ScanM includes a plurality of first pulse periods P1.
The number of the initial pulse period P0 and the first pulse period P1 in the modulated scan signal ScanM is not limited in the present application, and only the sum of the pulse periods of the modulated scan signal ScanM occupies one frame. For example, the modulated scan signal ScanM may include one initial pulse period P0 and a plurality of first pulse periods P1. The modulated scan signal ScanM may include a plurality of initial pulse periods P0 and a first pulse period P1.
Specifically, the time of the first pulse period P1 may be two initial pulse periods P0, three initial pulse periods P0, four initial pulse periods P0, five initial pulse periods P0, six initial pulse periods P0, seven initial pulse periods P0, eight initial pulse periods P0, ten initial pulse periods P0, sixteen initial pulse periods P0, or thirty-two initial pulse periods P0.
Further, please continue to refer to fig. 3. The low-level pulse width is increased to modulate a plurality of initial pulse periods P0 within one frame into P first pulse periods P1. The scan signal to be modulated ScanO in one frame includes 127 initial pulse periods P0, and the scan signal to be modulated ScanM in one frame includes one initial pulse period P0 and P first pulse periods P1. The first pulse period P1 is the time of two initial pulse periods P0. Wherein p has a value of 63.
Specifically, the display panel with 127 gray scales has 127 minimum subfield times t within one frame time. Then one row of the scan signal to be modulated ScanO has 127 initial pulse periods P0. At this time P is 127, the duration of the first pulse period P1 is equal to the duration of two initial pulse periods P0, so that 126 initial pulse periods P0 in one frame are modulated into 63 first pulse periods P1. The modulated scan signal ScanM includes one initial pulse period P0 and 63 first pulse periods P1. Finally, 127 high-level pulses in one frame of the scan signal ScanO to be modulated are modulated into 64 high-level pulses of the modulated scan signal ScanM. That is, the time for which the TFT is applied with the high level voltage is reduced by half, thereby improving the shift of the threshold voltage.
In fig. 3, the arrangement order of the initial pulse period P0 and the first pulse period P1 is merely illustrative and not intended to limit the present application.
Referring to fig. 4, fig. 4 is a second schematic diagram of a scanning signal before and after modulation provided by the present application. Similarly, fig. 4 illustrates a scan signal of a certain line in fig. 2, and the pulse period of the scan signal in a frame is compressed.
In some embodiments, modulating the low-level pulse width of the scan signal ScanO to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal ScanO to be modulated, so that the number of high-level pulses of the scan signal ScanM after modulation is less than the number of high-level pulses of the scan signal ScanO to be modulated, includes:
increasing the low-level pulse width, modulating at least one initial pulse period P0 into a first pulse period P1, and modulating at least one initial pulse period P0 into a second pulse period P2, so that the number of high-level pulses of the modulated scanning signal ScanM is less than that of the scanning signal ScanO to be modulated; the scan signal ScanO to be modulated includes a plurality of initial pulse periods P0, the scan signal ScanM after being modulated includes a plurality of first pulse periods P1 and a plurality of second pulse periods P2, the time of the initial pulse period P0 is less than the time of the first pulse period P1, and the time of the first pulse period P1 is less than the time of the second pulse period P2.
The number of the initial pulse period P0, the first pulse period P1, and the second pulse period P2 in the modulated scan signal ScanM is not limited in the present application, and only the sum of the pulse periods of the modulated scan signal ScanM is required to occupy one frame. For example, the modulated scan signal ScanM may include an initial pulse period P0, a first pulse period P1, and a plurality of second pulse periods P2. The modulated scan signal ScanM may include an initial pulse period P0, a plurality of first pulse periods P1, and a second pulse period P2.
Specifically, the time of the first pulse period P1 may be the time of two initial pulse periods P0, the time of three initial pulse periods P0, the time of four initial pulse periods P0, the time of five initial pulse periods P0, the time of six initial pulse periods P0, the time of seven initial pulse periods P0, the time of eight initial pulse periods P0, the time of ten initial pulse periods P0, or the time of sixteen initial pulse periods P0.
Specifically, the second pulse period P2 can be two initial pulse periods P0, three initial pulse periods P0, four initial pulse periods P0, five initial pulse periods P0, six initial pulse periods P0, seven initial pulse periods P0, eight initial pulse periods P0, ten initial pulse periods P0, sixteen initial pulse periods P0, or thirty-two initial pulse periods P0.
In some embodiments, the first pulse period P1 is two initial pulse periods P0, and the second pulse period P2 is four initial pulse periods P0.
Further, please continue to refer to fig. 4. The plurality of initial pulse periods P0 are modulated into n first pulse periods P1 and m second pulse periods P2. The modulated scan signal ScanM includes an initial pulse period P0, n first pulse periods P1, and m second pulse periods P2. The duration of the first pulse period P1 is two initial pulse periods P0, and the duration of the second pulse period P2 is four initial pulse periods P0. Wherein the sum of n and m is 32, and m and n are positive integers more than 1.
In some embodiments, n has a value of 1 and m has a value of 31. The following description will be made by taking a 127 gray scale display panel as an example. The display panel with 127 gray scales has 127 minimum subfield times t within one frame time. Then one row of the scan signal to be modulated ScanO has 127 initial pulse periods P0. n has a value of 1 and m has a value of 31. Thus, 126 initial pulse periods P0 within one frame are modulated into 1 first pulse period P1 and 31 second pulse periods P2. The modulated scan signal ScanM includes one initial pulse period P0, 1 first pulse period P1, and 31 second pulse periods P2. Finally, 127 high-level pulses in one frame of the scan signal ScanO to be modulated are modulated into 33 high-level pulses of the modulated scan signal ScanM. Namely, the time of the TFT under the high level voltage is reduced to one third of the original time. This greatly reduces the TFT stressing time and also greatly improves the TFT stability, thereby improving the threshold voltage drift.
In fig. 4, the arrangement sequence of the initial pulse period P0, the first pulse period P1 and the second pulse period P2 is only illustrative and is not intended to limit the present application.
In one embodiment, the display panel is a 127 gray scale display panel. The 127 gray-scale display panel has 127 minimum subfield times t within one frame time. One row of the scan signal to be modulated ScanO has 127 initial pulse periods P0. The scan signal ScanO to be modulated is modulated according to the pwm signal, and the modulated scan signal ScanM has an initial pulse period P0, a first pulse period P1, a second pulse period P2, a third pulse period P3, a fourth pulse period P4, and three fifth pulse periods P5.
The time of the first pulse period P1 is the time of two initial pulse periods P0. The second pulse period P2 is the time of the four initial pulse periods P0. The third pulse period P3 is the time of the eight initial pulse periods P0. The fourth pulse period P4 is the same time as the sixteen initial pulse periods P0. The fifth pulse period P5 is a period of thirty-two initial pulse periods P0.
Thereby, 127 high-level pulses in the scan signal ScanO to be modulated are modulated into 8 high-level pulses of the modulated scan signal ScanM. The number of high-level pulses is greatly reduced, and the high-level pulse time is greatly shortened. The high-voltage action time of the scanning signals on the TFT is greatly reduced, the stability of the TFT is improved, and the problem of drift of the threshold voltage is well solved.
In practical tests, modulating the pulse period to be greater than thirty-two initial pulse periods P0 will have an effect on the luminance of the display panel. Therefore, to ensure the display effect, the pulse period after modulation is controlled to range from 2 to 32 initial pulse periods P0.
13. And outputting the modulated scanning signal to a backlight driving circuit.
Referring to fig. 5, fig. 5 is a circuit diagram of a backlight driving circuit in the backlight driving method provided by the present application. The backlight driving circuit 10 includes a first transistor T1, a second transistor T2, a storage capacitor C, and a light emitting device LED. The source of the first transistor T1 is connected to the cathode of the light emitting device LED, the drain of the first transistor T1 is grounded, and the gate of the first transistor T1 is electrically connected to the first node N. The source of the second transistor T2 is connected to the Data signal Data, the drain of the second transistor T2 is electrically connected to the first node N, and the gate of the second transistor T2 is connected to the modulated scan signal ScanM. The first end of the storage capacitor C is electrically connected with the first node N, and the second end of the storage capacitor C is grounded. The anode of the light emitting device LED is connected to a power signal VDD.
Referring to fig. 4 and 5, in an embodiment, the modulated scan signal ScanM includes an initial pulse period P0, a first pulse period P1, and 31 second pulse periods P2, which are sequentially arranged. By adopting the sequence, the potential of the first node N can be raised in the first initial pulse period P0, and the storage capacitor C is charged, so that the light-emitting effect of the light-emitting device LED is ensured. And then the low-level pulse width is prolonged, so that the influence of the low-level pulse width on the subsequent light emission of the LED can be reduced.
Referring to fig. 6, fig. 6 is a timing diagram of a backlight driving circuit in the backlight driving method provided in the present application. When the modulated scan signal ScanM is at a high level, the Data signal Data is at a high level, and a high-level pulse width of the Data signal Data is greater than a high-level pulse width corresponding to the modulated scan signal ScanM.
The modulated scanning signal ScanM provided by the application reduces the high-level pulse times and increases the low-level pulse width. The high-level pulse width of the Data signal Data is greater than that of the modulated scan signal ScanM, so that the Data signal Data can be input when the modulated scan signal ScanM controls the second transistor T2 to be turned on. When the modulated scan signal ScanM controls the second transistor T2 to be turned off, the potential of the first node N is kept high, so that the light emitting device LED can still emit light uniformly when the modulated scan signal ScanM is at a low level.
Due to the time sequence setting, the influence of the modulated scanning signal ScanM on the light emission of the display panel can be avoided.
According to the backlight driving method, the low-level pulse width of the scanning signal is modulated through a pulse width modulation technology. The number of high level pulses is reduced by increasing the low level pulse width to increase the pulse period, thereby reducing the high level pulse time. The time that the TFT is subjected to the high level voltage is also reduced, thereby improving the stability of the TFT and also improving the problem of threshold voltage shift of the TFT.
Please refer to fig. 7, wherein fig. 7 is a schematic structural diagram of a display panel according to the present application. The display panel 100 provided by the present application includes a backlight module, and the backlight module is provided with a plurality of rows of backlight driving circuits, and the backlight driving circuits are driven by the above-mentioned backlight driving method.
The display panel 100 provided in the present application may be used in an electronic device, and the electronic device may be at least one of a smart phone (smartphone), a tablet personal computer (tablet personal computer), a mobile phone (mobile phone), a video phone, an electronic book reader (e-book reader), a desktop computer (desktop PC), a laptop computer (laptop PC), a netbook computer (netbook computer), a workstation (workstation), a server, a personal digital assistant (personal digital assistant), a portable media player (portable multimedia player), an MP3 player, a mobile medical machine, a camera, a game machine, a digital camera, a car navigation device, an electronic billboard, an automatic teller machine, or a wearable device (wearable device).
The display panel 100 provided by the present application includes a backlight module, and a backlight driving circuit is disposed on the backlight module. The backlight driving circuit is driven by a backlight driving method which modulates a low level pulse width of a scanning signal by a pulse width modulation technique. The number of high level pulses is reduced by increasing the low level pulse width to increase the pulse period, thereby reducing the high level pulse time. The time that the TFT is subjected to the high level voltage is also reduced, thereby improving the stability of the TFT and also improving the problem of threshold voltage shift of the TFT.
The backlight driving method and the display panel provided by the present application are described in detail above, and the principle and the implementation of the present application are explained in the present application by applying specific examples, and the description of the above examples is only used to help understanding the method and the core idea of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.
Claims (14)
1. A backlight driving method, comprising:
providing a pulse width modulation signal;
modulating the low-level pulse width of a scanning signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scanning signal to be modulated, so that the number of high-level pulses of the scanning signal after modulation is less than that of the scanning signal to be modulated;
outputting the modulated scanning signal to a backlight driving circuit;
the scanning signal to be modulated in a frame includes 127 initial pulse periods, and the modulating the low-level pulse width of the scanning signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scanning signal to be modulated, so that the number of high-level pulses of the scanning signal after modulation is less than the number of high-level pulses of the scanning signal to be modulated, including:
Increasing the pulse width of a low level, and modulating at least one initial pulse period into a first pulse period, wherein the time of the first pulse period is the time of at least two initial pulse periods, so that the modulated scanning signal comprises a plurality of first pulse periods;
the modulating the low-level pulse width of the scanning signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scanning signal to be modulated, so that the number of times of the high-level pulse of the scanning signal after modulation is less than that of the high-level pulse of the scanning signal to be modulated, including:
modulating the scanning signal to be modulated in one frame to comprise one initial pulse period and p first pulse periods, wherein the time of the first pulse period is the time of two initial pulse periods; wherein p has a value of 63.
2. The backlight driving method according to claim 1, wherein the scan signal to be modulated in one frame includes a plurality of initial pulse periods, and the modulating the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated so that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated comprises:
Increasing the pulse width of a low level, and modulating a plurality of initial pulse periods in one frame into n first pulse periods and m second pulse periods, so that the modulated scanning signal in one frame comprises one initial pulse period, n first pulse periods and m second pulse periods, wherein the time of the first pulse period is the time of two initial pulse periods, and the time of the second pulse period is the time of four initial pulse periods; wherein the sum of n and m is 32, and m and n are positive integers more than 1.
3. The backlight driving method according to claim 2, wherein the scan signal to be modulated in one frame includes 127 initial pulse periods, and the modulating the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated so that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated comprises:
and modulating the scanning signal to be modulated in one frame to comprise one initial pulse period, one first pulse period and 31 second pulse periods.
4. The backlight driving method according to claim 3, wherein the modulated scanning signal comprises one of the initial pulse periods, one of the first pulse periods, and 31 of the second pulse periods, which are sequentially arranged.
5. The backlight driving method according to claim 1, wherein the backlight driving method is applied to a backlight driving circuit including a first transistor, a second transistor, a storage capacitor, and a light emitting device;
the source electrode of the first transistor is connected to the cathode of the light-emitting device, the drain electrode of the first transistor is grounded, and the grid electrode of the first transistor is electrically connected with a first node;
a source electrode of the second transistor is connected with a data signal, a drain electrode of the second transistor is electrically connected with a first node, and a grid electrode of the second transistor is connected with a modulated scanning signal;
the first end of the storage capacitor is electrically connected with the first node, and the second end of the storage capacitor is grounded;
and the anode of the light-emitting device is connected with a power supply signal.
6. The backlight driving method according to claim 5, wherein when the modulated scanning signal is at a high level, the data signal is at a high level, and a high-level pulse width of the data signal is greater than a high-level pulse width corresponding to the modulated scanning signal.
7. A backlight driving method, comprising:
Providing a pulse width modulation signal;
modulating the low-level pulse width of a scanning signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scanning signal to be modulated, so that the number of high-level pulses of the modulated scanning signal is less than that of the scanning signal to be modulated;
outputting the modulated scanning signal to a backlight driving circuit;
the method for modulating the scanning signal to be modulated in a frame comprises a plurality of initial pulse periods, modulating the low-level pulse width of the scanning signal to be modulated according to the pulse width modulation signal so as to increase the pulse period of the scanning signal to be modulated, and enabling the number of high-level pulses of the scanning signal to be modulated to be less than that of the scanning signal to be modulated, and comprises the following steps:
increasing the low-level pulse width, modulating at least one initial pulse period into a first pulse period, and modulating at least one initial pulse period into a second pulse period, so that the modulated scanning signal comprises a plurality of first pulse periods and a plurality of second pulse periods, wherein the time of the initial pulse period is less than that of the first pulse period, and the time of the first pulse period is less than that of the second pulse period.
8. The backlight driving method according to claim 7, wherein the first pulse period is two initial pulse periods in time, and the second pulse period is four initial pulse periods in time.
9. The backlight driving method according to claim 7, wherein the scan signal to be modulated in one frame includes a plurality of initial pulse periods, and the modulating the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated so that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated comprises:
increasing the pulse width of a low level, and modulating a plurality of initial pulse periods in one frame into n first pulse periods and m second pulse periods, so that the modulated scanning signal in one frame comprises one initial pulse period, n first pulse periods and m second pulse periods, wherein the time of the first pulse period is the time of two initial pulse periods, and the time of the second pulse period is the time of four initial pulse periods; wherein the sum of n and m is 32, and m and n are positive integers more than 1.
10. The backlight driving method according to claim 9, wherein the scan signal to be modulated in one frame includes 127 initial pulse periods, and the modulating the low-level pulse width of the scan signal to be modulated according to the pulse width modulation signal to increase the pulse period of the scan signal to be modulated so that the number of high-level pulses of the modulated scan signal is less than the number of high-level pulses of the scan signal to be modulated comprises:
and modulating the scanning signal to be modulated in one frame to comprise one initial pulse period, one first pulse period and 31 second pulse periods.
11. The backlight driving method according to claim 10, wherein the modulated scanning signal comprises one of the initial pulse periods, one of the first pulse periods, and 31 of the second pulse periods, which are sequentially arranged.
12. The backlight driving method according to claim 7, wherein the backlight driving method is applied to a backlight driving circuit including a first transistor, a second transistor, a storage capacitor, and a light emitting device;
the source electrode of the first transistor is connected to the cathode of the light-emitting device, the drain electrode of the first transistor is grounded, and the grid electrode of the first transistor is electrically connected with a first node;
A source electrode of the second transistor is connected with a data signal, a drain electrode of the second transistor is electrically connected with a first node, and a grid electrode of the second transistor is connected with a modulated scanning signal;
the first end of the storage capacitor is electrically connected with the first node, and the second end of the storage capacitor is grounded;
and the anode of the light-emitting device is connected with a power supply signal.
13. The backlight driving method according to claim 12, wherein when the modulated scanning signal is at a high level, the data signal is at a high level, and a high-level pulse width of the data signal is greater than a high-level pulse width corresponding to the modulated scanning signal.
14. A display panel, comprising a backlight module, wherein a backlight driving circuit is disposed on the backlight module, and the backlight driving circuit is driven by the backlight driving method according to any one of claims 1 to 13.
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| CN202110389512.1A CN113129845B (en) | 2021-04-12 | 2021-04-12 | Backlight driving method and display panel |
| US17/289,291 US20240127761A1 (en) | 2021-04-12 | 2021-04-25 | Backlight driving method and display panel |
| PCT/CN2021/089595 WO2022217642A1 (en) | 2021-04-12 | 2021-04-25 | Backlight driving method and display panel |
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| CN202110389512.1A CN113129845B (en) | 2021-04-12 | 2021-04-12 | Backlight driving method and display panel |
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| US20070262732A1 (en) * | 2006-05-10 | 2007-11-15 | Vastview Technology Inc. | Method for controlling LED-based backlight module |
| CN101419789B (en) * | 2008-12-04 | 2010-12-01 | 上海广电光电子有限公司 | Restoration device for liquid crystal device and driving method thereof |
| JP5307527B2 (en) * | 2008-12-16 | 2013-10-02 | ルネサスエレクトロニクス株式会社 | Display device, display panel driver, and backlight driving method |
| US8907884B2 (en) * | 2010-01-06 | 2014-12-09 | Apple Inc. | LED backlight system |
| CN104575399A (en) * | 2015-02-13 | 2015-04-29 | 广东威创视讯科技股份有限公司 | Light-emitting diode pixel circuit and light-emitting diode display |
| US10127859B2 (en) * | 2016-12-29 | 2018-11-13 | Lg Display Co., Ltd. | Electroluminescent display |
| CN107452344A (en) * | 2017-08-18 | 2017-12-08 | 京东方科技集团股份有限公司 | The adjusting method and device of a kind of backlight |
| CN111951736B (en) * | 2019-05-17 | 2022-08-12 | 京东方科技集团股份有限公司 | Backlight module, driving method and driving device thereof and display device |
| CN112331130A (en) * | 2019-07-31 | 2021-02-05 | Tcl集团股份有限公司 | Drive method and drive device of quantum dot light-emitting diode and display device |
| CN110782831B (en) * | 2019-11-05 | 2021-02-26 | 京东方科技集团股份有限公司 | Pixel driving circuit, display device, and pixel driving circuit driving method |
| CN111276097B (en) * | 2020-03-26 | 2022-05-20 | 京东方科技集团股份有限公司 | Pixel driving circuit, driving method thereof and display substrate |
| CN111508430B (en) * | 2020-04-28 | 2021-07-09 | 昆山国显光电有限公司 | Frequency conversion refreshing method, pixel driving method, device and electronic equipment |
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| WO2022217642A1 (en) | 2022-10-20 |
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