CN108305591B - Display control method and display device - Google Patents
Display control method and display device Download PDFInfo
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- CN108305591B CN108305591B CN201810146037.3A CN201810146037A CN108305591B CN 108305591 B CN108305591 B CN 108305591B CN 201810146037 A CN201810146037 A CN 201810146037A CN 108305591 B CN108305591 B CN 108305591B
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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
- G09G3/36—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 using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3696—Generation of voltages supplied to electrode drivers
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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
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0257—Reduction of after-image effects
Abstract
The embodiment of the invention provides a display control method and a display device, wherein the method comprises the following steps: setting the current driving voltage of the thin film transistor TFT as an initial driving voltage; detecting the continuous display time of the current frame image; determining a target driving voltage corresponding to the continuous display time; and adjusting the current driving voltage according to the target driving voltage. According to the method, the corresponding target driving voltage is determined by detecting the change of the continuous display time of the current frame image, and the current driving voltage of the TFT is further adjusted according to the target driving voltage, so that the number of the current driving voltage can be increased, and the drift of the TFT and the afterimage caused by the drift can be reduced.
Description
Technical Field
The invention relates to the technical field of liquid crystal display, in particular to a display control method and a display device.
Background
In recent years, liquid crystal displays have become popular due to their advantages of low operating voltage, low power consumption, low radiation, low space occupation, light weight, and good appearance, and thus become the mainstream of the market. With the increasing level of understanding and the increasing demand for display, the image quality of the display is also required to be higher and higher, and the current liquid crystal display in the market has the following problems in terms of image quality:
when a TFT-LCD (Thin Film Transistor-Liquid Crystal Display) displays a same sub-picture for a long time, Liquid Crystal molecules cannot normally deflect under the control of signal voltage because the Liquid Crystal is driven by a long-time dc bias voltage, so that the picture generates an afterimage, that is, after the image of the displayed picture is changed, the trace of a static image at the previous time can still be seen on the screen.
Disclosure of Invention
The invention provides a display control method and a display device aiming at the defects of the prior art, and aims to solve the problem that the residual image is generated when a liquid crystal display displays the same picture image for a long time in the prior art.
According to an aspect, an embodiment of the present invention provides a display control method, including:
setting the current driving voltage of the thin film transistor TFT as an initial driving voltage;
detecting the continuous display time of the current frame image;
determining a target driving voltage corresponding to the continuous display time;
and adjusting the current driving voltage according to the target driving voltage.
Further, determining the target driving voltage corresponding to the continuous display time includes:
comparing the continuous display time with at least one preset time, judging whether the continuous display time is greater than any one preset time, and if so, determining a target driving voltage corresponding to the continuous display time;
adjusting the current driving voltage according to the target driving voltage, including: and adjusting the current off-state voltage Vgl of the TFT according to the target driving voltage.
Further, judging whether the continuous display time is longer than any one preset time or not; if yes, determining the target driving voltage corresponding to the continuous display time, including:
judging whether the continuous display time is longer than a first preset time, if so, determining that the target driving voltage is a first target driving voltage; otherwise, judging whether the continuous display time is greater than a second preset time.
Further, judging whether the continuous display time is longer than any one preset time or not; if yes, determining the target driving voltage corresponding to the continuous display time, and further comprising:
if the continuous display time is judged to be longer than a second preset time, determining that the target driving voltage is a second target driving voltage; otherwise, judging whether the continuous display time is greater than a third preset time.
Further, judging whether the continuous display time is longer than any one preset time or not; if yes, determining the target driving voltage corresponding to the continuous display time, and further comprising:
and if the continuous display time is judged to be longer than a third preset time, determining that the target driving voltage is a third target driving voltage.
Further, the method further comprises:
when the continuous display time is judged to be less than or equal to the first preset time and switching to a next frame image for display is detected, determining an image difference value between the next frame image and the current frame image;
and judging whether the image difference value is larger than a preset image difference threshold value, if so, adjusting the current driving voltage of the TFT to the initial driving voltage, and determining the continuous display time of the next frame of image from the beginning.
Further, the method further comprises:
and if the image difference value is less than or equal to the image difference threshold value, accumulating the continuous display time of the next frame image into the continuous display time of the current frame image.
According to another aspect, an embodiment of the present invention further provides a display device, including a voltage setting module, a time detecting module, a voltage determining module, and a voltage adjusting module, which are electrically connected in sequence;
the voltage setting module is used for setting the current driving voltage of the thin film transistor TFT as the initial driving voltage; the time detection module is used for detecting the continuous display time of the current frame image; the voltage determining module is used for determining a target driving voltage corresponding to the continuous display time; and the voltage regulating module is used for regulating the current driving voltage according to the target driving voltage.
Further, the voltage regulation module includes: the circuit comprises a signal input end, a feedback voltage adjusting unit, a driving voltage adjusting unit, a first resistor and a signal output end;
the first end of the feedback voltage regulating unit is electrically connected with the signal input end, the second end of the feedback voltage regulating unit is electrically connected with the first end of the driving voltage regulating unit, and the third end of the feedback voltage regulating unit is grounded; the second end of the driving voltage regulating unit is electrically connected with the signal output end; the first resistor is connected in parallel with the driving voltage regulating unit;
the feedback voltage regulating unit is used for receiving a control signal corresponding to the target driving voltage through the signal input end, generating a corresponding feedback voltage signal according to the control signal and transmitting the feedback voltage signal to the driving voltage regulating unit; and the driving voltage adjusting unit is used for generating a corresponding adjusted driving voltage signal according to the feedback voltage signal and outputting the driving voltage signal through the signal output end.
Further, the feedback voltage adjusting unit includes at least one set of adjusting circuits, each set of adjusting circuits includes: an amplifier, a switching device and a second resistor;
the anode of the amplifier is electrically connected with the signal input end, and the cathode of the amplifier is electrically connected with the first end of the switching device; a first pole of the switching device is electrically connected with a first end of the second resistor, and a second pole of the switching device is grounded; a second end of the second resistor is electrically connected with the driving voltage adjusting unit and the first resistor;
the amplifier is used for amplifying the control signal input by the signal input end; and the switching device is used for being switched on or off under the control of the control signal so as to realize the on-off of the adjusting circuit of the group.
Compared with the prior art, the embodiment of the invention at least has the following beneficial effects:
1) the number of the current driving voltage can be increased by detecting the change of the continuous display time of the current frame image, determining the corresponding target driving voltage and further adjusting the current driving voltage of the TFT according to the target driving voltage, so that the drift of the TFT and the afterimage caused by the drift can be reduced;
2) the method comprises the steps that through judgment of image difference values, the next frame of image can be properly processed according to different situations, when the image difference values are small, continuous display of the next frame of image is accumulated to the continuous display time of the current frame of image, and the current driving voltage is continuously adjusted to improve afterimages caused by the current frame of image; when the image difference value is larger, the continuous display time of the next frame of image is independently calculated, and the current driving voltage under the next frame of image is adjusted according to the continuous display time so as to improve the afterimage caused by the next frame of image;
3) and outputting the corresponding FB voltage by adopting the voltage regulating module according to the target driving voltage control signal, and further regulating and outputting the corresponding driving voltage signal, so that the current driving voltage of the TFT can be regulated based on the continuous display time.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic diagram of a frame image before switching frames in an afterimage test according to the present invention.
FIG. 2 is a diagram illustrating a screen image after switching the screen in the afterimage test according to the present invention.
Fig. 3 is a graph comparing characteristics of TFTs in regions a and b in fig. 2.
FIG. 4 is a comparison graph of the TFT characteristics at different Vgs obtained by high temperature negative polarity bias test on the TFT in the present invention.
Fig. 5 is a flowchart illustrating a display control method according to an embodiment of the present invention.
Fig. 6 is a flowchart illustrating another display control method according to a second embodiment of the present invention.
Fig. 7 is a flowchart illustrating a specific example of a display control method according to a second embodiment of the present invention.
Fig. 8 is a schematic structural diagram of a display device according to a third embodiment of the present invention.
Fig. 9 is a schematic structural diagram of a voltage regulation module according to a third embodiment of the present invention.
Fig. 10 is a schematic diagram of an operating waveform of a voltage regulation module according to a third embodiment of the present invention.
Fig. 11 is a schematic structural diagram of another display device according to a fourth embodiment of the present invention.
Detailed Description
The afterimage is a Display characteristic of a TFT-LCD (Thin Film Transistor-Liquid Crystal Display), and mainly shows that when the same picture is displayed on the LCD for a long time, the original picture will remain in the next picture when the picture is switched to the next picture. In the development process of TFT-LCD, the problem of image retention has long influenced the picture quality of TFT-LCD, especially the long-term picture quality.
In order to solve the problem of the afterimage, the inventors of the present invention conducted an afterimage test. Fig. 1 and fig. 2 respectively show two successive residual image test pictures obtained when performing a residual image test On a TFT-LCD (Gate Driver On Array) product as an example; fig. 1 is a screen image before switching, and fig. 2 is a screen image after switching. In the switched L127 screen, the a region and the b region should be displayed at the same gray level and have the same brightness, but in fig. 2, the brightness of the a region and the b region is significantly different, and an afterimage is formed. L127 is a luminance parameter indicating that the luminance or the gradation is 127 th level.
In order to better understand the mechanism of forming the afterimage, the inventor of the present invention has studied and analyzed the TFT characteristics of the a-region and the b-region after switching the picture, and as for the LCD product, the scanning mode is gate progressive scanning, and as for the black-grid and white-grid TFTs, only 1/768 frames are on, and 767/768 frames are off, so the influence of the on-state voltage Vgh of the TFT can be ignored, and only the influence of the off-state voltage Vgl (-8V) on the TFT characteristics, that is, only the change of the drain-source current Ids when Vgl is-8V is considered.
The above-mentioned relevant parameters have the following meanings: the on-state voltage Vgh is Vgatehigh, which represents the high potential of the gate (gate) of the TFT, i.e., the voltage for turning on the gate, and when this voltage is reached, the TFT is in an on-state (conducting state); the off-state voltage Vgl is Vgatelow, which represents the low potential of the gate of the TFT, i.e., the voltage for turning off the gate, and when the voltage is reached, the TFT is in an off state (cut-off state); the drain-source current Ids is the current between the drain (drain) and source (source) of the TFT, and when the TFT is in the off state, it should theoretically be Ids ═ 0, but there will actually be a drain-source current Ids.
Fig. 3 is a graph showing a comparison of TFT characteristics of an a-region and a b-region after switching of a screen, where a dotted line in fig. 3 indicates the TFT characteristics of the a-region, a dashed-dotted line indicates the TFT characteristics of the b-region, an abscissa indicates an off-state voltage Vgl of the TFT, and an ordinate indicates a drain-source current Ids of the TFT.
As can be seen from fig. 3, Ids of the a region and the b region of the switched picture is most different between the abscissa Vgl-10V to-6V, that is, the TFT characteristics are most different between the a region and the b region when Vgl-10V to-6V; under the same Vgl, Ids of the a region and the b region are different, so that pixel leakage is different, and VHR (voltage holding ratio) of the two regions is also different, which finally causes a difference in luminance between the a region and the b region, thereby forming an afterimage.
For the black and white lattice TFT, the DS voltage difference (drain and source voltage difference) is considered to be 0V when the TFT is in the off state, the pixel voltage Vpixel of the white lattice (the source voltage Vs of the TFT) is in the transition of 0V and 16V (the positive and negative frame inversion, each takes 50% of the time), and the pixel voltage Vpixel of the black lattice is always approximately in the 8V state. The gate-source voltage (or gate bias voltage) Vgs of the TFT is Vg-Vs, and the gate voltage Vg and Vgl are equal without considering Vgh, so that Vgs can be derived to be Vgl-Vs, and when only the influence of Vgl-8V is considered, it can be calculated that when Vpixel of the white lattice jumps between 0V and 16V in the afterimage experiment, the white lattice TFT is actually subjected to the influence of Vgs of-8V and-24V alternately (each occupying 50% of the time length); when the Vpixel of the black lattice is approximately 8V in the afterimage experiment, the black lattice TFT is actually subjected to Vgs of approximately-16V.
The inventor of the present invention further performed NBTPS Test (high Temperature Negative polarity Bias Test) on the TFT, which was performed under a condition similar to actual driving, for testing the influence of different Vgl on the TFT characteristics under the same drain-source voltage Vds, and which can be used to evaluate the stability of the TFT and ensure the reliability of the product. The drain-source voltage Vds is a voltage between the drain and the source of the TFT, and the corresponding current is a drain-source current Ids.
The specific test conditions for the NBTPS test were: irradiating with light at 5000nit (nit), temperature of 25 deg.C, and testing for 2hr (hour); where nit is the unit of luminance, 1nit is 1cd/m2(candela/m squared). After the 2hr test, a comparison graph of the TFT characteristics at different Vgs is obtained as shown in fig. 4, and fig. 4 lists TFT characteristics at different Vgs when Vds is 15V and 8V, respectively, where the values of Vds and Vgs are not shown in the coordinates of fig. 4.
The four TFT characteristics in fig. 4 are from top to bottom: the Vds is a TFT characteristic curve (long-dashed line portion, hereinafter referred to as "first curve") when 15V, Vgs is at-16V, the Vds is a TFT characteristic curve (dotted line portion, hereinafter referred to as "second curve") when 15V, Vgs jumps between-8V and-24V, the Vds is a TFT characteristic curve (solid line portion, hereinafter referred to as "third curve") when 8V, Vgs jumps between-8V and-24V, and the Vds is a TFT characteristic curve (short-dashed line portion, hereinafter referred to as "fourth curve") when 8V, Vgs jumps between-8V and-24V.
Comparing the two previous curves, the ordinate value of the first curve is larger than that of the second curve, and it can be inferred that when Vds is 15V, when Vgs jumps between-8V and-24V, the leakage current Ioff (off-state current of the TFT, i.e. drain-source current Ids of the TFT in an off-state) is relatively small, so that the TFT drift is relatively small, and when Vgs is-16V, Ioff is relatively large, so that the TFT drift is relatively large; similarly, comparing the two curves, it can be seen that the ordinate value of the third curve is greater than that of the fourth curve, and it can be inferred that when Vds is 8V, when Vgs jumps between-8V and-24V, Ioff is relatively small, so that TFT drift is relatively small, and when Vgs is-16V, Ioff is relatively large, so that TFT drift is relatively large.
Based on the above analysis, the inventors found that the influence of the same Vgs on the TFT characteristics is large, and the residual image is easier to form, and that the influence of different Vgs on the TFT characteristics is small, and the residual image is easier to reduce. It is further inferred that when Vgl does not change or changes little during a long-time display of one screen image, and corresponding Vgs does not change or changes little, it is very easy to cause the formation of afterimages.
Based on the above findings, the inventor of the present invention proposes a method and a device for controlling display of a screen, which increase the number of Vgs transitions of TFTs when displaying the same screen by adjusting the corresponding off-state voltage Vgl at regular time when detecting that the LCD displays the same screen for a long time, so as to reduce the afterimage caused by the drift of the TFT characteristics.
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative only and should not be construed as limiting the invention.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or wirelessly coupled. As used herein, the term "and/or" includes all or any element and all combinations of one or more of the associated listed items.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Example one
In order to solve the afterimage caused by the too small number of Vgs, the first embodiment of the present invention provides a display control method. The flow diagram of the method is shown in fig. 5, and includes:
s101, setting the current driving voltage of a Thin Film Transistor (TFT) as an initial driving voltage;
s102, detecting the continuous display time of the current frame image;
s103, determining a target driving voltage corresponding to the continuous display time;
and S104, adjusting the current driving voltage according to the target driving voltage.
By applying the embodiment of the invention, the number of the current driving voltages can be increased by detecting the change of the continuous display time of the current frame image, determining the corresponding target driving voltage and further adjusting the current driving voltage of the TFT according to the target driving voltage, and the increase of the number of Vgs caused by the increase of the number of the current driving voltages can reduce the drift of the TFT and the afterimage caused by the drift.
The technical solution of the first embodiment of the present invention is explained in detail below:
in step S101, the current driving voltage of the TFT is the off-state voltage Vgl of the TFT, the current driving voltage of the TFT is set as the initial driving voltage, and the initial driving voltage is used as the main voltage of the driving voltage, so that the driving voltage can be fixed at a voltage, and the driving voltage is prevented from being switched among a plurality of voltages, thereby effectively saving power consumption when the LCD does not display the same picture image for a long time.
Setting the current driving voltage of the TFT as the initial driving voltage, which is specifically as follows: setting an initial control signal, and outputting corresponding Vgl under the control of the initial control signal as an initial driving voltage.
Before step S102, the current frame image may also be stored, so as to facilitate subsequent processing of the image.
In step S102, the continuous display time may be represented by time, for example, 10 minutes; the unit time may also be set to be directly expressed by the number of unit times that the image is displayed for, e.g., 36000 unit times for the continuous display time.
When the continuous display time is represented by time, it is further preferable that the step S102 includes: when detecting that the current frame image starts to be displayed, recording the number of unit time by using a counter; and determining the total time according to the unit time and the number of the unit time to be used as the continuous display time of the current frame image. The continuous display time can be accurately detected by the mode.
When the continuous display time is represented by the number of the continuous unit time, it is further preferable that the step S102 includes: when the display of the current frame image is detected, the number of the unit time is recorded by using a counter. By the mode, the continuous display time can be detected more efficiently, and meanwhile, the power consumption can be further reduced due to the fact that the calculation steps are reduced.
Preferably, step S103 includes: and comparing the continuous display time with at least one preset time, judging whether the continuous display time is greater than any one preset time, and if so, determining a target driving voltage corresponding to the continuous display time.
Corresponding to step S102, the preset time in step S103 may be expressed as a specific time value or may be expressed as the number of a certain unit time.
When more than one preset time is set, the sequence of comparison and judgment is not limited, the judgment can be carried out in sequence from large to small or from small to large according to the size of the preset time, and the specific sequence can be set according to the actual requirement of a user.
The embodiment of the invention does not limit the quantity of the preset time, namely the judgment times; the more the number of the preset time is, the more the judgment times are, the more the number of the obtained driving voltages is, the more the improvement of the image retention is facilitated, and the specific numerical value can be flexibly set according to the actual requirement and the limiting condition.
The embodiment of the invention also has no limitation on the length of the preset time, and can be flexibly set according to the actual design mode and the requirement.
When the duration display time is represented by the number of the unit time that is continued, the preset time may also be represented by the number of the preset unit time.
In a preferred embodiment, three preset times are set in consideration of the power consumption requirement, and three judgment processes are performed, specifically including the following steps:
firstly, judging whether the continuous display time is longer than a first preset time, if so, determining that the target driving voltage is a first target driving voltage; otherwise, judging whether the continuous display time is greater than a second preset time;
if the continuous display time is judged to be longer than the second preset time, determining that the target driving voltage is a second target driving voltage; otherwise, judging whether the continuous display time is longer than a third preset time.
And if the continuous display time is judged to be longer than the third preset time, determining that the target driving voltage is a third target driving voltage.
The preset time is set to be three, and compared with the situation that the preset time is less than three, the beneficial effects are as follows: the number of the target driving voltages can be increased for more judgments, so that the number of Vgs is increased, and the afterimage of the picture is effectively improved; compared with the situation of more than three, the beneficial effects are as follows: avoiding excessive power consumption caused by switching Vgs too frequently. On the premise of meeting the requirement of power consumption, the preferred embodiment can increase the number of Vgs to the maximum extent, thereby improving the afterimage of the picture to the maximum extent.
According to the actual requirements of users, on the premise of meeting the actual power consumption requirements, the preset time can be set to be other number.
When it is determined that the continuous display time is longer than the maximum preset time of the plurality of preset times, the determined target driving voltage corresponding to the maximum preset time, and the next frame of image is not detected, the embodiment of the present invention may further include: returning to step S101, the above steps are repeated.
Preferably, step S104 specifically includes: and generating a corresponding control signal according to the target driving voltage, controlling the control signal to generate a corresponding driving voltage signal, and adjusting the current driving voltage from the initial driving voltage to the driving voltage corresponding to the driving voltage signal.
Example two
Based on the same inventive concept, the second embodiment of the invention provides a display control method. Fig. 6 shows a schematic flow chart of the method, and based on S101-S104 in the first embodiment of the present invention, the method further includes:
s105, when the continuous display time is judged to be less than or equal to a first preset time and switching to a next frame image for display is detected, determining an image difference value between the next frame image and the current frame image;
s106, judging whether the image difference value is larger than a preset image difference threshold value; if yes, the next frame image and the current frame image are considered to be different images, and step S101 is executed; if not, the difference is ignored, and step S107 is executed after the next frame image and the current frame image are the same image.
Step S107, detecting the continuous display time of the next frame image, accumulating the continuous display time of the next frame image into the continuous display time of the current frame image, and executing step S103
In step S106, the current driving voltage of the TFT is readjusted to the initial driving voltage, and the next frame image is used as a new current frame image (the current frame image at that time), and the continuous display time of the next frame image is determined from the beginning;
in step S107, the next frame image and the current frame image are regarded as the same image, and the continuous display time of the next frame image is integrated into the continuous display time of the current frame image, which corresponds to the continuous display time of the current frame image being detected continuously.
Through the judgment of the image difference value, the next frame of image can be properly processed according to different situations, when the image difference value is small, the continuous display of the next frame of image is accumulated into the continuous display time of the current frame of image, the Vgs number of the current frame of image can be further increased, and the afterimage caused by the current frame of image can be better improved; when the image difference value is larger, the continuous display time of the next frame image is independently calculated, and the Vgs number of the next frame image is increased according to the continuous display time so as to improve the afterimage caused by the next frame image.
The embodiment of the invention does not limit the specific numerical value of the preset image difference threshold, and the smaller the numerical value is, the more the difference between two frames of images is easy to distinguish accurately, but the smaller the numerical value is, the more the number of cycles from head to head is, the power consumption is increased; in practical applications, a suitable value can be set according to the actual accuracy and the power consumption requirement.
Fig. 7 shows a specific example of the display control method, which specifically includes the following steps:
1) assigning Y0 to 1, Y1 to 0, and Y2 to 0, inputting an initial control signal, and making VGL to VGL0, thereby adjusting the current driving voltage VGL of the TFT to the initial driving voltage VGL 0;
2) the counter is increased by 1 unit time;
3) judging whether the counter is larger than 54000 unit time or not;
if the number of unit times is larger than 54000, the value Y0 is set to 1, Y1 is set to 0, Y2 is set to 0, and a first control signal is input to make VGL set to VGL0, so that the current driving voltage VGL of the TFT is adjusted to VGL 0;
if the continuous display time is less than or equal to 54000 unit times, judging whether the continuous display time is more than 36000 unit times;
if the current driving voltage is more than 36000 unit times, the assigned value Y0 is 0, Y1 is 1, Y2 is 0, and a second control signal is input to enable VGL to be VGL1 so as to adjust the current driving voltage VGL of the TFT to be VGL 1;
if the continuous display time is less than or equal to 36000 unit times, judging whether the continuous display time is more than 18000;
if the current driving voltage VGL is greater than 18000, the assigned value Y0 is 0, Y1 is 0, and Y2 is 1, and the third control signal is input to make VGL be VGL2, thereby adjusting the current driving voltage VGL of the TFT to VGL 2.
4) When the continuous display time is less than or equal to 54000 and switching to the next frame image for display is detected, determining an image difference value between the next frame image and the current frame image;
5) judging whether the image difference value is greater than 20%;
if yes, resetting the counter, returning to the step 1), taking the next frame image as a new current frame image, and determining the continuous display time of the next frame image from the beginning;
and if not, returning to the step 5), detecting the continuous display time of the next frame image, and accumulating the continuous display time into the continuous display time of the current frame image.
EXAMPLE III
Correspondingly, the third embodiment of the invention provides a display device. The schematic structural diagram of the display device is shown in fig. 8, and includes a voltage setting module 401, a time detection module 402, a voltage determination module 403, and a voltage adjustment module 404 according to the third embodiment, which are connected in sequence.
The voltage setting module 401 is configured to set a current driving voltage of the TFT to an initial driving voltage; and is specifically used for: an initial control signal of the voltage adjusting module 404 is set, and the corresponding Vgl is output as an initial driving voltage under the control of the initial control signal.
The voltage setting module 401 uses the initial driving voltage as the main voltage of the driving voltage to fix the main voltage of the driving voltage, so that the driving voltage can be prevented from being switched among a plurality of voltage values, and power consumption can be effectively saved when the LCD does not display the same picture for a long time.
The time detection module 402 is configured to detect a continuous display time of the current frame image; and is specifically used for: when the display start of the current frame image is detected, the number of the unit time is recorded by using a counter, and/or the time sum is determined according to the unit time and the number of the unit time as the continuous display time of the current frame image.
The voltage determining module 403 is configured to determine a target driving voltage corresponding to a sustained display time; and is specifically used for: and comparing the continuous display time with at least one preset time, judging whether the continuous display time is greater than any one preset time, and if so, determining a target driving voltage corresponding to the continuous display time.
In a preferred embodiment, the voltage determining module 403 is specifically configured to:
firstly, judging whether the continuous display time is longer than a first preset time, if so, determining that the target driving voltage is a first target driving voltage; otherwise, judging whether the continuous display time is greater than a second preset time or not;
if the continuous display time is judged to be longer than the second preset time, determining that the target driving voltage is a second target driving voltage; otherwise, judging whether the continuous display time is longer than a third preset time.
And if the continuous display time is judged to be longer than the third preset time, determining that the target driving voltage is a third target driving voltage.
The voltage adjusting module 404 is configured to adjust a current driving voltage according to a target driving voltage; and is specifically used for: and generating a corresponding driving voltage signal according to the control signal corresponding to the target driving voltage, and adjusting the current driving voltage from the initial driving voltage to the driving voltage corresponding to the driving voltage signal.
In a preferred embodiment, the voltage regulation module 404 includes: the circuit comprises a signal input end, a feedback voltage adjusting unit, a driving voltage adjusting unit, a first resistor and a signal output end; fig. 9 shows a schematic diagram of the voltage regulation module 404.
The first end of the feedback voltage regulating unit is electrically connected with the signal input end, the second end of the feedback voltage regulating unit is electrically connected with the first end of the driving voltage regulating unit, and the third end of the feedback voltage regulating unit is grounded; the second end of the driving voltage regulating unit is electrically connected with the signal output end; the first resistor is connected in parallel with the driving voltage regulating unit;
the feedback voltage regulating unit is used for receiving a control signal corresponding to the target driving voltage through the signal input end, generating a corresponding feedback voltage (FB voltage) signal according to the control signal and transmitting the feedback voltage signal to the driving voltage regulating unit; the driving voltage adjusting unit is used for generating a corresponding adjusted driving voltage signal according to the feedback voltage signal and outputting the driving voltage signal through the signal output end.
Preferably, the signal input includes at least one input port, such as Y0, Y1, and Y2 shown in fig. 9. A control signal corresponding to the initial driving voltage or the target driving voltage is input to the voltage regulating module 404 through the signal input terminal.
Preferably, the feedback voltage adjusting unit includes at least one set of adjusting circuits, each set of adjusting circuits including: an amplifier, a switching device, and a second resistor (resistor R0, R1, or R2 shown in fig. 7);
the anode of the amplifier is electrically connected with the signal input end, and the cathode of the amplifier is electrically connected with the first end of the switching device; the first pole of the switching device is electrically connected with the first end of the second resistor, and the second pole of the switching device is grounded; the second end of the second resistor is electrically connected with the driving voltage adjusting unit and the first resistor.
The amplifier is used for amplifying the control signal input by the signal input end; the switch device is used for being opened or closed under the control of the control signal so as to realize the on-off of the adjusting circuit of the group.
The first resistor (shown as resistor R in fig. 9) and the second resistor are voltage dividing resistors.
When the NMOS transistor (metal-oxide-semiconductor field effect transistor) shown in fig. 9 is selected, the gate of the NMOS transistor is the control terminal of the switching device, the drain is the first pole of the switching device, and the source is the second pole of the switching device.
The driving voltage adjusting unit may be a BUCK circuit (BUCK converter circuit) as shown in fig. 9.
The voltage regulation module 404 operates on the principle that the signal input terminal is assigned to input a control signal corresponding to the target driving voltage to regulate the magnitude of the FB voltage, and the output of the VGL is further controlled by regulating the magnitude of the FB voltage.
Referring to the waveform diagram of the operation of the voltage regulation module 404 shown in fig. 10, the operation process of the voltage regulation module 404 provided by the embodiment of the present invention is specifically as follows:
when the value of Y0 is 1, Y1 is 0, and Y2 is 0, that is, a first control signal is input, the first control signal is amplified by an amplifier, an NMOS tube M0 is controlled to be opened, and M1 and M2 are controlled to be closed, at this time, only a resistor R0 and GND are in a conducting state, that is, a corresponding FB voltage is obtained, at this time, the FB voltage and the VGL voltage have an operation relationship of FB-VGL × R0/(R0+ R), and a BUCK circuit can generate and output a current driving voltage VGL-VGL 0 of a corresponding TFT according to the FB voltage and the operation relationship;
when the value of Y0 is 0, Y1 is 1, and Y2 is 0, a second control signal is input, the second control signal is amplified by the amplifier, the NMOS transistor M1 is controlled to be turned on, and M0 and M2 are controlled to be turned off, at this time, only the resistor R1 and GND are in a conducting state, and a corresponding FB voltage is obtained, at this time, the FB voltage and the VGL voltage have an operational relationship of FB-VGL × R1/(R1+ R), and the BUCK circuit can generate and output the current driving voltage VGL of the corresponding TFT-VGL 1 according to the FB voltage and the operational relationship;
when the value of Y0 is 0, Y1 is 0, and Y2 is 1, the third control signal is input, the third control signal is amplified by the amplifier, the NMOS transistor M2 is controlled to be turned on, and M0 and M1 are controlled to be turned off, at this time, only the resistor R2 and GND are in a conducting state, and the corresponding FB voltage is obtained, at this time, the FB voltage and the VGL voltage have an operation relationship of FB-VGL × R2/(R2+ R), and the BUCK circuit can generate and output the current driving voltage VGL of the corresponding TFT-VGL 2 according to the FB voltage and the operation relationship.
By applying the voltage regulating module 404 provided by the embodiment of the present invention, the corresponding FB voltage can be output according to the control signal corresponding to the target driving voltage, and the corresponding driving voltage signal is further output through the regulation of the BUCK circuit, so as to realize the current driving voltage regulation of the TFT.
The beneficial effects that can be achieved by the third embodiment of the present invention are the same as those of the first embodiment, and are not described herein again.
Example four
Correspondingly, the fourth embodiment of the invention provides a display device. Fig. 11 shows a schematic structural diagram of the apparatus, and on the basis of the third embodiment of the present invention, the apparatus further includes an image difference determining module 405 and an image difference determining module 406, which are electrically connected to each other, the image difference determining module 405 is further electrically connected to the voltage adjusting module 404, and the image difference determining module 406 is further electrically connected to the voltage setting module 401 and the time detecting module 402.
The image difference determining module 405 is configured to determine an image difference value between a next frame image and a current frame image when it is determined that the continuous display time is less than or equal to a first preset time and it is detected that the next frame image is switched to be displayed.
The image difference determining module 406 is configured to determine whether the image difference value is greater than a preset image difference threshold;
if yes, the control voltage setting module 401 executes step S101 to adjust the current driving voltage of the TFT to the initial driving voltage, use the next frame image as a new current frame image, and determine the continuous display time of the next frame image from the beginning;
if not, the control time detecting module 402 executes step S102 to detect the continuous display time of the next frame image (the current frame image at that time), and control the time detecting module 402 to accumulate the continuous display time of the next frame image into the continuous display time of the current frame image.
The beneficial effects that the fourth embodiment of the present invention can achieve are the same as the second embodiment, and are not described herein again.
It will be understood by those within the art that each block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions. Those skilled in the art will appreciate that the computer program instructions may be implemented by a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, implement the features specified in the block or blocks of the block diagrams and/or flowchart illustrations of the present disclosure.
Those of skill in the art will appreciate that various operations, methods, steps in the processes, acts, or solutions discussed in the present application may be alternated, modified, combined, or deleted. Further, various operations, methods, steps in the flows, which have been discussed in the present application, may be interchanged, modified, rearranged, decomposed, combined, or eliminated. Further, steps, measures, schemes in the various operations, methods, procedures disclosed in the prior art and the present invention can also be alternated, changed, rearranged, decomposed, combined, or deleted.
The foregoing is only a partial embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (9)
1. A display control method, comprising:
setting the current driving voltage of the thin film transistor TFT as an initial driving voltage;
detecting the continuous display time of the current frame image;
determining a target driving voltage corresponding to the continuous display time, including: comparing the continuous display time with at least one preset time, judging whether the continuous display time is greater than any one preset time, and if so, determining a target driving voltage corresponding to the continuous display time;
adjusting the current driving voltage according to the target driving voltage, including: and adjusting the current off-state voltage Vgl of the TFT according to the target driving voltage.
2. The method according to claim 1, wherein said determining whether said duration is longer than any of said predetermined times; if yes, determining the target driving voltage corresponding to the continuous display time, including:
judging whether the continuous display time is longer than a first preset time, if so, determining that the target driving voltage is a first target driving voltage; otherwise, judging whether the continuous display time is greater than a second preset time.
3. The method according to claim 2, wherein said determining whether said duration is longer than any of said predetermined times; if yes, determining the target driving voltage corresponding to the continuous display time, and further comprising:
if the continuous display time is judged to be longer than a second preset time, determining that the target driving voltage is a second target driving voltage; otherwise, judging whether the continuous display time is greater than a third preset time.
4. The method according to claim 3, wherein said determining whether said duration is longer than any of said predetermined time; if yes, determining the target driving voltage corresponding to the continuous display time, and further comprising:
and if the continuous display time is judged to be longer than a third preset time, determining that the target driving voltage is a third target driving voltage.
5. The method of claim 2, further comprising:
when the continuous display time is judged to be less than or equal to the first preset time and switching to a next frame image for display is detected, determining an image difference value between the next frame image and the current frame image;
and judging whether the image difference value is larger than a preset image difference threshold value, if so, adjusting the current driving voltage of the TFT to the initial driving voltage, and determining the continuous display time of the next frame of image from the beginning.
6. The method of claim 5, further comprising:
and if the image difference value is less than or equal to the image difference threshold value, accumulating the continuous display time of the next frame image into the continuous display time of the current frame image.
7. A display device is characterized by comprising a voltage setting module, a time detection module, a voltage determination module and a voltage regulation module which are electrically connected in sequence;
the voltage setting module is used for setting the current driving voltage of the thin film transistor TFT as the initial driving voltage;
the time detection module is used for detecting the continuous display time of the current frame image;
the voltage determining module is used for determining a target driving voltage corresponding to the continuous display time; the method is specifically used for: comparing the continuous display time with at least one preset time, judging whether the continuous display time is greater than any one preset time, and if so, determining a target driving voltage corresponding to the continuous display time;
the voltage adjusting module is used for adjusting the current driving voltage according to the target driving voltage; the method is specifically used for: and adjusting the current off-state voltage Vgl of the TFT according to the target driving voltage.
8. The apparatus of claim 7, wherein the voltage regulation module comprises: the circuit comprises a signal input end, a feedback voltage adjusting unit, a driving voltage adjusting unit, a first resistor and a signal output end;
the first end of the feedback voltage regulating unit is electrically connected with the signal input end, the second end of the feedback voltage regulating unit is electrically connected with the first end of the driving voltage regulating unit, and the third end of the feedback voltage regulating unit is grounded; the second end of the driving voltage regulating unit is electrically connected with the signal output end; the first resistor is connected in parallel with the driving voltage regulating unit;
the feedback voltage regulating unit is used for receiving a control signal corresponding to the target driving voltage through the signal input end, generating a corresponding feedback voltage signal according to the control signal and transmitting the feedback voltage signal to the driving voltage regulating unit; and the driving voltage adjusting unit is used for generating a corresponding adjusted driving voltage signal according to the feedback voltage signal and outputting the driving voltage signal through the signal output end.
9. The apparatus of claim 8, wherein the feedback voltage regulating unit comprises at least one set of regulating circuits, each set of regulating circuits comprising: an amplifier, a switching device and a second resistor;
the anode of the amplifier is electrically connected with the signal input end, and the cathode of the amplifier is electrically connected with the first end of the switching device; a first pole of the switching device is electrically connected with a first end of the second resistor, and a second pole of the switching device is grounded; a second end of the second resistor is electrically connected with the driving voltage adjusting unit and the first resistor;
the amplifier is used for amplifying the control signal input by the signal input end; and the switching device is used for being switched on or off under the control of the control signal so as to realize the on-off of the adjusting circuit of the group.
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| CN103778897B (en) * | 2014-01-28 | 2016-03-02 | 北京京东方显示技术有限公司 | A kind of image display control method and device |
| KR20170123400A (en) * | 2016-04-28 | 2017-11-08 | 엘지디스플레이 주식회사 | Organic light emitting display panel, organic light emitting display device, and the method for driving the organic light emitting display device |
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